The paper of When gentamicin-loaded bone cement  became available in Germany in the 1970s, efforts to treat osteomyelitis by filling the debrided cavity with solid plugs of antibiotic-loaded bone cement were not successful in patients in France and Germany, nor in animal experiments in the Mayo Clinics . Thus, KOne of the arguments against the use of antibiotic-loaded beads is the lack of proof of effectivity in good randomized clinical trials (RCTs). The most cited RCT was performed in the US in an attempt to get FDA approval, in 380 patients with osteomyelitis: systemic antibiotic treatment versus gentamicin beads. However, the protocol was violated because surgeons worried about withholding systemic antibiotics from patients who were treated with beads. In this trial, however, the costs were lower when beads were used, and there were less systemic adverse events with antibiotics when local antibiotics were used (as compared to treatment with systemic antibiotics) . AnotherAn RCT was even performed in a developing country. This rarely cited study was done in an isolated Himalayan region of Nepal. Lars Lindberg  and Margareta Höök treated 45 patients with debridement followed by the use of gentamicin beads or open treatment package of the debrided cavity . The ranIn the developing countries surgeons also became aware of the benefit of local antibiotic treatment of bone infections. The Septopal beads were, however, too expensive and surgeons had to look for alternative solutions. Beads made of plaster of Paris were an important alternative in the beginning.The use of plaster of Paris in bone defects had been known since 1892, when Trendelenburg in Bonn (Germany) filled bone defects . AdmixtuFor many years, a group of Dutch orthopedic surgeons used preformed gentamicin-containing plaster of Paris beads during their visits to Indonesia and Africa; these were made by a pharmacist at the hospital in Arnhem . So gent-1) than Septopal beads (8.6 cm -1), so the release is worse. The paper of Rasyid et al. describes how a method can be developed to create hand-made gentamicin-loaded PMMA beads with very good pharmacokinetic properties in combination with substantially reduced costs when compared with the commercially available beads : 112 USD instead of 350 USD.The production by orthopedic surgeons in Indonesia of hand-made beads was originally done by mixing bone cement with fosfomycin, an antibiotic often used in developing countries . They foThese authors used an elegant method to increase the antibiotic release: simply the reduction of the monomer content by 50%, which causes large pores in the incompletely polymerized polymer particles. Porosity is one of the most important factors in the process of sustained release of bone cement . In SeptIn western countries, improvement of antibiotic release from bone cement is also important. Spacers have a low surface area to volume ratio, resulting in a limited and often insufficient release of antibiotic . In the Staphylococcus aureus and S. epidermidis, possibly in combination with gentamicin  that made it possible to order vancomycin-gentamicin PMMA beads for an individual patient, based on the resistance pattern of a causative agent . For 5 yFinally, molds are helpful in the production of hand-made beads. Surgeons should be aware that beads or spacers that they make themselves must have good pharmacokinetic properties to be effective, and that not all kinds of antibiotics may be released properly from bone cement. With the special technique for improvement of antibiotic release properties of bone cement described in the article of Neut et al., and the use of a mold, it is now possible for the surgeon to make customized antibiotic-loaded PMMA beads with different antibiotics and with an improved antibiotic release. We will need this technique increasingly for prosthetic joint infections and osteomyelitis, since resistant bacteria such as CNS, MRSE and MRSA are becoming ever more frequent. It is remarkable that the scientific help of a western university (Groningen) to solve a problem in a developing country may improve the treatment of bone and joint infections in many centres in the western world itself.


Carotid intima-media thickness (CIMT) measured by B-mode ultrasonography is a marker of atherosclerosis and is commonly used as an outcome in intervention trials. We have developed DICOM-based software that measures CIMT rapidly on multiple end-diastolic image frames. The aims of this study were to compare the performance of our new software with older bitmap-based CIMT measurement software and to determine whether a ten-fold increase in the number of measurements used to calculate mean CIMT would improve reproducibility.Two independent sonographers recorded replicate carotid scans in thirty volunteers and two blinded observers measured CIMT off-line using the new DICOM-based software and older bitmap-based software. A Bland-Altman plot was used to compare CIMT results from the two software programs and t-tests were used to compare analysis times. F-tests were used to compare the co-efficients of variation (CVs) from a standard six-frame measurement protocol with CVs from a sixty-frame measurement protocol. Ordinary least products (OLP) regression was used to test for sonographer and observer biases.The new DICOM-based software was much faster than older bitmap-based software  but CIMT measurements were larger than those made using the alternative software . The sixty-frame measurement protocol had worse reproducibility than the six-frame protocol  and inter and intra-observer biases were more pronounced in the sixty-frame than the six-frame results.While the use of DICOM-based software significantly reduced analysis time, a ten-fold increase in the number of measurements used to calculate CIMT did not improve reproducibility. In addition, we found that observer biases caused differences in mean CIMT of a magnitude commonly reported as significant in intervention trials. Our results highlight the importance of good study design with concurrent controls and the need to ensure that no observer drift occurs between baseline and follow-up measurements when CIMT is used to monitor the effect of an intervention. Carotid intima-medial thickness (CIMT), measured with B-mode ultrasound, is a marker for atherosclerosis. CIMT is correlated with the known risk factors for cardiovascular disease and is an independent predictor of myocardial infarction and ischemic stroke -6. ConseEdge-detection software has become the accepted standard for CIMT measurement. The use of software improves CIMT reproducibility and reduces observer bias compared with manual techniques ,15. UntiWe have developed software that measures CIMT rapidly on the multiple end-diastolic image frames contained in a single DICOM file. We hypothesize that increasing the number of measurements used to estimate CIMT will reduce random measurement error and improve reproducibility. In addition, DICOM-based software will reduce CIMT measurement time compared with older software by eliminating the requirement to open multiple individual image files. The aims of this study are to compare our new DICOM-based CIMT measurement software with older bitmap-based software and to determine whether a ten-fold increase in the number of image frames used to estimate CIMT improves reproducibility. We have also conducted a systematic review of previously published CIMT reproducibility data.The study protocol was approved by the Royal Perth Hospital Ethics Committee and all subjects gave written informed consent prior to taking part.30 volunteers chosen to have a range of CIMT values were recruited for the study. Eight subjects were normal healthy volunteers, seven had disordered lipid metabolism and fifteen subjects had a history of stroke or transient ischemic attack. Subject characteristics are presented in Table The subject lay supine on an examination couch with their head turned 45 degrees away from the side being scanned. The sonographers obtained longitudinal B-mode images of the left and right common carotid arteries, immediately proximal to the carotid bifurcation. Each sonographer adjusted focus and gain settings to optimise far-wall echoes and to minimise noise in the arterial lumen. Dynamic range and image presets, including persistence, edge tracking and pre and post-processing, were not changed between scans. A three lead ECG trace was recorded simultaneously with the B-mode images. The sonographers recorded image sequences for twenty seconds from each of three standardised probe angles  in both the left and right common carotids. Each subject thus had four scans (two visits and two sonographers) and each scan consisted six twenty-second image sequences (three from the left carotid and three from the right) stored as a single DICOM file. The 120 scans were recorded to a computer hard-drive using the digital acquisition system described below. A unique four digit ID was used to identify each scan so that observers measuring the CIMT were blinded to subject, visit number and sonographer.A 10 MHz multi-frequency linear array probe attached to a high-resolution ultrasound machine  was used to record the ultrasound images. A 75Ω coaxial cable from the video output port of the ultrasound machine was plugged into the video input port of a National Instruments IMAQ-PCI-1411, single channel, 8-bit colour image-acquisition board. The analogue video output from the ultrasound machine was converted into a digital DICOM 3.0 file in real time by proprietary DICOM Encoder software and stored on the hard-drive of a standard personal computer running Windows 2000. Image sequences recorded in the DICOM format are stored in a single file as a series of JPEG images that can be viewed individually frame by frame or played as a continuous video sequence. The ultrasound image sequences were acquired at a rate of 25 frames per second and at a resolution of 768 × 576 pixels. A typical scan was two minutes in length, contained approximately 3000 individual image frames and was approximately 250 megabytes in size.The CIMT analysis software is written in the icon-based graphical programming language LabVIEW 6.1™ and uses an IMAQ™ vision tool kit for image handling and analysis routines. The software is designed to read DICOM files but can also read single bitmap, TIFF or JPEG image files.The observer opens a DICOM file in the analysis software and draws a rectangular region of interest (ROI) around the ECG trace Figure . An autoThe software uses an automated edge-detection algorithm to locate the arterial wall interfaces within the user-selected ROI. The program automatically detects the centre of the artery and divides the ROI into an upper half that contains the near wall lumen-intima interface and a lower half that contains the far wall interfaces. A particle erosion routine is used to condition the image for edge detection by eliminating noise in the lumen of the artery. The threshold used to identify noise is calculated separately for the upper and lower ROI's using a statistical clustering method. The same threshold is also used in the edge detection algorithm. The near-wall intimal edge is initially identified by a Rake routine that scans from the bottom to the top of the upper half of the ROI. The Rake routine uses three parameters of contrast, filter width and steepness to identify and confirm the location of the edge. Contrast is dynamically adjusted for each frame using the calculated threshold value and represents the difference in the average pixel intensity before and after the edge. Filter width specifies the number of pixels averaged either side of the edge and steepness refers to the rate of change of pixel intensity across the edge. The edge is further defined by removing any point outside a pre-set statistical limit.The same algorithm is used to find the far wall lumen edge, by scanning from the top to bottom of the lower half of the ROI. When the lumen edge has been detected, all the pixels of the intima and media are set to zero (black) and the Rake routine is employed again to find the far wall media-adventitia interface. The edge-detection algorithm identifies the near and far wall lumen edges and the far wall media-adventitia interface on every frame selected for analysis. This process is almost instantaneous for a single frame and takes approximately 10 seconds for 400 consecutive frames.When edge detection is complete, the software displays a magnified ROI and marks the lumen margins and the far wall media-adventitia interface with coloured lines Figure . The sofIf a single frame is selected for analysis, the length of each pixel column is displayed as a data point on a graph below the image. If multiple frames are selected for analysis the software calculates the mean lumen diameter and the mean CIMT for each frame and displays these values as data points on the graphical display. The results from a multiple frame analysis are shown in Figure When the observer is confident that the three interfaces have been accurately identified on the selected frames, the software calculates the mean, maximum and minimum CIMT and lumen diameter. The results of the calculation are displayed in a table to the left of the image  on all 120 scans were used for the sonographer comparisons. A random sample of 41 scans was selected for the observer comparisons and was analysed twice by each observer with a minimum of one week between first and second analyses.carotid intima medial thickness or IMT or intima media and validation or reproducibility or software or edge-tracking. We also searched for reproducibility statistics in the method sections of papers reporting CIMT as an outcome. We included all studies that reported inter- and intra-sonographer and observer CVs and calculated CVs for other papers when the appropriate data was given (mean CIMT and SD of absolute differences).We also conducted a systematic review of the literature to allow comparison of our reproducibility results with previous studies. We conducted Medline and Google searches and manually searched citation lists of relevant papers. The keywords we used were A Bland-Altman plot was used to compare the new software with alternative CIMT measurement software. We used a paired t-test to compare the mean CIMT measurement time for each program. The co-efficients of variation (CVs) from a standard six-frame measurement protocol were compared with CVs from the sixty-frame measurement protocol using F-tests. Ordinary least products (OLP) regression was used to test for sonographer and observer biases. We chose OLP regression to test for bias as it allows for both the x and y values to be attended by random error and thus requires no judgement about whether the y variable or the x variable provides 'true' values . It is tFigure The sixty-frame measurement protocol did not significantly improve reproducibility compared with the standard six-frame protocol Figure . An appaTable We identified twenty-eight published studies that reported suitable reproducibility data for CIMT measurement. The CVs from these studies, along with data from the current project, are presented in Table This study has produced several results of interest to investigators using CIMT as a marker of cardiovascular risk. Our new DICOM-based software halved CIMT measurement time compared with an alternative system designed to read bitmap files. However, increasing the number of measurements used to estimate CIMT did not improve reproducibility and measuring CIMT on sixty-frames appeared to increase the risk of bias within and between observers compared with measuring CIMT on fewer frames.The strengths of this study were that we validated our software in subjects with a wide range of CIMT values and tested it against an alternative software program. We used blinded observers and the study was designed so we could measure sonographer and observer reproducibility separately. We also conducted a systematic review of previously published CIMT reproducibility data. A limitation of this study was that one observer did not perform replicate measures with the multiple-frame protocol, reducing our ability to detect improvements in intra-observer reproducibility.The CIMT values from our software were approximately half a pixel larger than CIMT values from the alternative software  with evidence of an increase in the size of the differences for larger CIMT values  in measured CIMT. Although this difference may seem trivial, it should be noted that CIMT progresses very slowly in most people, at the rate of 0.001 mm to 0.03 mm per year ,33. ReduWhile the use of DICOM-based software significantly reduced analysis time, a ten-fold increase in the number of measurements used to calculate CIMT did not improve reproducibility. In addition, we found that observer biases caused differences in mean CIMT of a magnitude commonly reported as significant in intervention trials. Our results highlight the importance of good study design with concurrent controls and the need to ensure that no observer drift occurs between baseline and follow-up measurements when CIMT is used to monitor the effect of an intervention.The author(s) declare that they have no competing interests.KP was participated in the design of the study, recorded the ultrasound scans, made the CIMT measurements, wrote the manuscript and performed the statistical analysis. DJG participated in the design of the study, obtained funding for the software development, and critically reviewed the manuscript. CJR wrote and developed the software, gave technical assistance and critically reviewed the manuscript. RFW recorded the ultrasound scans, assisted with interpretation of the data and statistical analysis, and assisted with manuscript preparation. GFW participated in the design of the study, obtained funding for the software and critically reviewed the manuscript. BMM participated in the design of the study and critically reviewed the manuscript. VB participated in the design of the study, assisted with statistical analysis and critically reviewed the manuscript. GJH critically reviewed the manuscript. LFA participated in the design of the study and critically reviewed the manuscript. All authors read and approved the final manuscript.


A well-documented fact for a group of persistent, bioaccumulating organohalogens contaminants, namely polychlorinated biphenyls (PCBs), is that appropriate regulation was delayed, on average, up to 50 years. Some of the delay may be attributed to the fact that the science of toxicology was in its infancy when PCBs were introduced in 1920's. Nevertheless, even following the development of modern toxicology this story repeats itself 45 years later with polybrominated diphenyl ethers (PBDEs) another compound of concern for public health. The question is why? One possible explanation may be the low coherence between experimental studies of toxic effects in animal models and human studies. To explore this further, we reviewed a total of 807 PubMed abstracts and full texts reporting studies of toxic effects of PCB and PBDE in animal models. Our analysis documents that human epidemiological studies of PBDE stand to gain little from animal studies due to the following: 1) the significant delay between the commercialisation of a substance and studies with animal models; 2) experimental exposure levels in animals are several orders of magnitude higher than exposures in the general human population; 3) the limited set of evidence-based endocrine endpoints; 4) the traditional testing sequence  postpones investigation of the critical developmental stages; 5) limited number of animal species with human-like toxicokinetics, physiology of development and pregnancy; 6) lack of suitable experimental outcomes for the purpose of epidemiological studies. Our comparison of published PCB and PBDE studies underscore an important shortcoming: history has, unfortunately, repeated itself. Broadening the crosstalk between the various branches of toxicology should therefore accelerate accumulation of data to enable timely and appropriate regulatory action. The history of research on a group of persistent, bioaccumulating organohalogen environmental contaminants, namely polychlorinated biphenyls (PCBs), shows serious delays in the accumulation of necessary data for the purpose of toxic-substance policy making and regulatory action . Delays Could delays in regulatory action be at least partly attributable to the low coherence between experimental studies of toxic effects in animal models and human studies? In other words, to what extent the outputs of animal studies aid in the design of human studies? Animal models play an important role in studying the toxic effects of hazardous substances, determining dose-response relationships, and pinpointing the most susceptible developmental stages. The results of animal experiments form an important input for human studies which influence directly the policy making process. Any discordance between them may slow down the regulatory process. Hence, an important question is to what extent the outputs of existing animal experiments correspond to the input requirements for human studies?To answer this question, we compared the animal-study histories of two groups of well known organohalogen contaminants: PCBs and PBDEs (polybrominated diphenyl ethers). PCBs have been relatively well studied compared to PBDE which are a relatively new group with a much shorter history of studies. In addition, we also ask what lessons, if any, are to be drawn from history?in vitro experiments with animal cells and tissues; (2) reviews; (3) experiments whose exposure was not controlled ; (4) strictly toxicokinetic reports not addressing health effects; (5) experiments using various metabolites and derivatives of PBDEs and/or PCBs; (6) experiments using heterogeneous mixtures of contaminants (i.e. mixtures consisting not only of PCB or PBDE congeners). Mixtures of PBDEs or PCBs congeners were included. In other words, only reports of in vivo animal experiments addressing health effects of controlled exposure to PCBs or PBDEs were selected. No other restrictions were applied. 748 out of a total of 6076 PCB articles and 59 out of 649 PBDE articles met our selection criteria and were retained for analysis . The following reports of experiments with animal models were excluded from the subsequent analysis: (1) It should be noted that PubMed databases do not effectively capture the older scientific literature that predated the internet and existed only in print media. Thus, the first PCB studies we analysed were from 1971 ,4 althouOur study is not a systematic review but rather reflection based on analysis of history. We analyse existing experiments with animals in order to see if the level of coherence with human studies can be a limitation for the development of the latter.In an attempt to approach existing animal data in a systematic fashion and determine whether they are compatible with existing and ongoing epidemiologic investigations on environmental contaminants, we designed a non-exhaustive set of basic requirements in order to better "harmonize" animal experiments for the purpose of data transfer to human studies.When considering animal toxicology studies with a view to timely toxic-substance policy making and regulatory action, "harmonized" experiments with animal models should fulfill at least six basic requirements. These are summarized below.1. Experiments must be completed long before the substance can become a public health concern and well enough in advance to allow timely policy making and regulatory action. Obviously, once a persistent, toxic substance has already accumulated in the environment, as was the case with PCBs, the problem is greatly compounded.To study time-trends in animal research we analysed the temporal distribution of all selected 748 PCB and 59 PBDE reports using the print publishing date with respect to the dates of the beginning of production, initial detection in human tissues, and subsequent ban.et al [2. The doses studied must be relevant to human exposure levels. Toxic effects and biomarkers drawn from exposures several fold higher than the levels of exposure of the general human population cannot be transferred directly to the studies of the general population since most of toxic substances exert different effects at different doses. Moreover, toxic effects obtained from dose-response studies performed at high doses cannot be extrapolated to existing low-dose exposures of the general population. This is so because a number of environmental toxicants display non-linear dose-response relationships. Non-monotonic dose-response curves were already reported for PCBs -7 and foet al  number oet al  reportedet al  pups expet al ,12 suggeIn short, the use of doses several fold higher than exposure levels for the general human population contributes little to our understanding of the risks incurred by that population.To analyse doses of PCB and/or PBDE used in animal experiments we extracted, when available, data on dosing protocols from all selected PCB and PBDE reports, namely dose of compound per individual administration (daily dose) and total number of administrations. Total dose was calculated by multiplying daily dose by number of administrations. An average daily and average total dose was calculated for each year as mean ± SE for all experiments reported in the respective year. In number of cases, more than one experiment was presented in single paper. We estimated as separate experiments, trials with animals within one paper if they differed at least in one of the following: animal species/strains, treated stages of development, administered compounds, daily exposure doses and total exposure doses.3. The most sensitive endpoints must be screened, i.e. health effects emerging at the lowest exposure levels. Adequate risk assessment for the general population must be based on the analysis of toxic effects on the most sensitive target organs and functions. Obviously it is impossible to start research of new substance with unknown properties with the most sensitive endpoints. It is thus necessary to screen a series of endpoints to identify the most sensitive as well as to use previously studied substances with similar structures (PCB for PBDE) to predict possible endpoints.To detect health effects in the general population exposed to low doses of environmental contaminants, biomarkers of effect are essential. Biomarker epidemiology is undergoing a rapid development and expansion and is quickly becoming one of the most promising areas of environmental research . Animal Therefore, comprehensive screening of the most sensitive endpoints and peripheral biomarkers of exposure is another necessary requirement for animal studies.We extracted data on the health effects of PCB or PBDE exposure for each experiment of each selected article when available and assigned them according to a slightly modified classification of the health effects used in ATSDR's (US Agency for Toxic Substances and Disease Registry) Toxicological Profiles. All effects were classified among the following groups: mortality, respiratory, cardiovascular, gastrointestinal, haematological, musculoskeletal, hepatic, renal, endocrine, dermal, ocular, metabolic, other systemic, immunological and lymphoreticular, neurological, reproductive, developmental effects, cancer and genotoxicity. We modified the classifications with respect to two aspects. First, endpoints dealing with endocrine activity of reproductive organs were considered as endocrine rather than reproductive effects. Second, all endpoints addressing different organs at early stages of development were assigned to the effect corresponding to the organ rather than development and only growth changes were considered as developmental, including developmental malformations, developmental landmarks and endpoints addressing foetal development.4. The most sensitive stages of development must be screened. A number of substances  are known developmental toxicants at low doses but do not display toxic properties for adults at the same concentrations. Therefore, the most sensitive stages of development must be screened so as avoid underestimation of the risks posed to the most susceptible and vulnerable populations. Obviously, it is impossible to start research on a new substance with unknown properties with the most sensitive stages. It is necessary however to screen of most sensitive ages as well as use already studied substances with similar structure (PCB for PBDE) to predict them. The particular sensitivity of early developmental stages to PCB exposure was shown in number of animal and human studies (see reviews -17). PBDWe extracted data on animal stages of development exposed to PCB or PBDE from all selected articles when available and assigned them to one of the following: prenatal exposure; neonatal exposure; perinatal exposure; adult exposure. All these types of exposures were further united into two groups: developmental exposures  and adult exposures. The temporal distribution of experiments with different types of exposure was analysed.et al [5. Ideally animal models should have human-like physiology and toxicokinetics. Differences in toxicokinetics predetermine different toxic effects in different species . For exaet al  estimateet al . This diIt is becoming increasingly clear that prenatal and neonatal stages of development are highly susceptible to a number of toxic substances . TherefoWe extracted data on animal species used in each experiment reported in selected articles to analyse time-trend distribution of taxa in PCB and PBDE experiments.6. Exposures must be verified by measurement of the internal dose. For animal data to transfer correctly to human studies, it is especially important to measure the internal dose since exposure levels are rarely measured in epidemiological studies and all the health effects are correlated with the internal dose.There is no universally accepted protocol for the correct estimation of internal dose of exposure. In fact, there is a broad range of protocols using different tissues, time-points, dose-parameters and chemical species. PBPK models are of use also. Given the large number of protocols for determining of internal dose, we simply verified presence or absence of any estimation of internal dose in the selected articles.We extracted from all selected papers, when available, data on estimation of internal dose of the administered substance in exposed animals. We considered that the internal dose had indeed been estimated if there was any type of measurement of residuals or metabolites of administered congeners done at any time point in any tissues of directly exposed animals or their offspring, in the case of developmental exposures.We used these basic requirements in order to "harmonize" reports of animal experiments for the purpose of data transfer to human studies. Our short list is by no means exclusive and may be extended by others. We assume that applying such requirements to the analysis of animal data is the first step to document the level of coherence between animal and human studies.We also added the route of exposure to our analysis of PCB and PBDE studies because it is, according to our personal experience, the subject of intense debate (in peer review processes) with experts often displaying widely varying opinions.It is commonly accepted that studying the mechanisms of toxicity greatly increases the relative value of animal model studies. Albeit highly interesting in itself, knowledge of toxicity mechanisms impacts only slightly on policy making and regulatory action. For instance, in spite of some 30 years of intensive research, we are still unclear on the specific mechanisms of PCB toxicity. What is clear, however, is that this knowledge gap should not have precluded the ban on PCB in the 1970's. That is why our short list does not include analysis of toxicity mechanisms for harmonizing purposes.Both PCB and PBDE are ubiquitous, persistent organohalogens. Until their ban in the 1970's, PCB accumulated in biota. The bioaccumulation of PBDE, which are still massively produced, continues.PCBs was first manufactured commercially in 1927. They were used as coolants and insulating fluids for transformers and capacitors, as stabilizing additives in flexible PVC coatings of electrical wiring and electronic components, as pesticide extenders, as cutting oils, flame retardants, hydraulic fluids, sealants , adhesives, wood floor finishes, paints, de-dusting agents, and in carbonless copy paper. Manufacture peaked in the 1960's when the total global production of PCB was estimated at 1.5 million tons per year . In 1966PCB-associated toxicity was recognized quite early due to a variety of industrial incidents . The mosPCB production was banned in most countries during the 1970's, some 50 years after its commercial introduction in the 1920's.PBDE are a group of flame retardant chemicals which are added to synthetic polymers. PBDE are thus found in various building materials, electronics, furnishings, motor vehicles, plastics, polyurethane foams, and textiles. The first patent for PBDE use as a flame retardant was issued in 1960 and manufacturing of commercial products containing PBDE begins in 1965  several PBDEs were first detected in the environment in 1979  and in bAlthough their health effects, especially at low doses, need to be studied further, PBDEs are nevertheless known to be associated with neurodevelopmental toxicity and thyroid hormone imbalance in rodents ,43-47.The European Union banned the use of penta- and octa-BDE in 2004 and recently banned deca-BDE in 2008. Penta-and octa-BDE were withdrawn from the North American market in 2004  but DecaThe introduction of PBDE coincided with the development of the modern environmental movement inspired partly by the scandalous story of PCB and including the development of toxicological sciences, the establishment of public environmental institutions and environmental legislation in countries around the world.via photochemical reactions [However, more than 40 years elapsed between the start of PBDE production in 1965 and the ban of most of the PBDE congeners. Deca-BDE is still in use in North America, but unfortunately produces banned lower-brominated congeners by natural debromination eactions -51, anaeeactions ,53 and meactions -56.The oldest experimental reports on PCB found through our PubMed search were published in 1971. This likely reflects the limitations of the electronic database rather than the first toxicological studies of PCB. The number of publications increased steadily every year thereafter Fig . The groIt is noteworthy that the number of PCB reports continued to rise despite PCB ban . The number of publications peaked in 1984 and then again in 1994. The first wave of interest was presumably triggered by current exposures and observed toxic effects, whereas the next was consecutive to emerging results from long-term epidemiological studies on the general population.The two oldest experimental studies on PBDE found through our PubMed search were published in 1980 ,58, seveHence, intensive research only started once PBDE had become ubiquitous, with high concentrations in biota. In Sweden, PBDE concentrations in breast milk increased by approximately two order of magnitude during last 30 years  and relaTo characterise actual rate of studies: 161 PCB papers and 44 PBDE papers (27% of number of PCB papers) were published during the last 5 years (2002–2007), while the ban was completed for PCB approximately 30 years before and was in the process for PBDE.It took approximately 40 years to detect PCB in human tissues since the start of production. The discovery of the ubiquitous presence of PCBs in fat tissues of humans was an important step in the recognition of their potential danger. This discovery was delayed by the inability to measure PCB residues with sensitive analytical methods. The PCB designation as ubiquitous environmental contaminants occurred in 1966 , one yeaOver a 30-year period, the average daily PCB doses used in experiments with animal models decreased steadily from hundreds of milligrams per kilogram of bodyweight (mg/kg bw) in the early 1970's, to hundreds of micrograms/kg bw presently Fig . Meanwhiet al. [With the benefit of hindsight from the PCB experience, investigators would be expected to choose PBDE doses closer to human daily exposures. However, PBDE experiments were nevertheless initially conducted Fig  with higet al.  at 0.2 μWe hypothesize that doses increased after 2005 because the no observed adverse effect level (NOAEL) was reached at doses used in 2005. To test this hypothesis we tested the developmental effects of subchronic exposures at low doses of PBDE with rat and sheep animal models.th to the 15th week of gestation. Decreased total triiodothyronine was observed in lambs of least exposed group upon delivery [Pregnant rats were exposed to vehicle or low doses of BDE-47 , the most prevalent PBDE congener found in human samples, by intravenous injections every 5 days, from gestational day 15 to postnatal day 20. Hyperactivity and decreased total thyroxine in offspring were observed in all tested groups . Similardelivery . BDE-47 Each new environmental contaminant poses the challenging quest for sensitive endpoints of toxicity. In spite of the large body of knowledge from toxicology, predicting the toxic properties of new contaminants on the basis of their chemical structure remains difficult. Systematic screening of the most sensitive endpoints is necessary for each potentially hazardous substance. The powerful new tools of "omics" research which appeared over the last decades will no doubt increasingly contribute to intensifying the investigation into the sensitive endpoints of toxicity. Two reports, both published in 2007, investigate PCB toxicity using microarray technology ,63. AnotIn general, similar profiles of endpoints are addressed in PCB and PBDE studies Fig . The ranSurprisingly, in spite of the important number of experiments on PCB carcinogenicity, information on the carcinogenicity of PBDE in animal models is still lacking. Although a number of studies indicate that certain congeners exhibit aryl hydrocarbon receptor (Ah-R)-mediated effects and are potent inducers of ethoxyresorufin-o-deethylase (EROD), direct studies of the carcinogenic properties of PBDE have yet to be reported.Because of the well known endocrine disruptive properties of organohalogens, we considered endocrine endpoints in more detail Fig . DespiteOne possibility is that the adrenal gland is insensitive to organohalogens. To test this hypothesis, we studied adrenal endpoints of low-dose PBDE toxicity in our developmental subchronic exposure rat model described hereinabove . In the There are no specific biomarkers of effects for PCBs. Numerous studies have attempted to correlate serum PCB levels with liver-associated enzymes in PCB-exposed workers and general population subjects; however, no conclusive association has been found [Further studies to identify specific biomarkers of effects of PCBs would facilitate medical surveillance leading to early detection of potentially adverse health and possible treatment." . Only t, the same trend was observed for PBDE reports . Moreover, the number of pre- and perinatal exposures versus neonatal exposures increased within PCB developmental experiments . The number of PBDE reports is too small to conclude any similar trend.The ratio of developmental Hence, investigators test adult animals before the more susceptible neonates. Foetuses, which are in fact the most susceptible, are tested last whereas they should logically be tested first.The diversity of the taxonomic groups used as animal models for both PCB and PBDE studies is shown in Figure Rodents are thus becoming the sole mammalian order used in most toxicological experiments. Each animal model presents advantages and limitations depending on the endpoints of interest. Advantages and role of rodent models in toxicological studies are well known. The use of the rodent models only in experimental toxicology is not sufficient however, since rodent models have some limitations, not covered in modern studies by any other species. For example, speaking about PCB and PBDE it has to be mentioned, that organohalogen toxicokinetics is very different in rodents and humans . RodentsArtiodactyla order (even-toed ungulates) are presumably good models for simulating human-like pregnancy and toxicokinetics [Although primates are the ideal model to simulate human physiology, development and toxicokinetics, their use is dwindling for ethical and financial considerations. An important problem stems from the fact that no other group with human-like parameters is used in most toxicological studies. Although having limitation as precocial species certain mammals of the kinetics , there aThe choice of dosing paradigm is a challenge. Estimation of the internal dose is thus a means of "quality control" and yields valuable information for the transfer of data from animal to human studies .β = 6.32; p = 0.01), it surprisingly tends to decrease slowly in PCB studies .The data on estimation of internal doses in PBDE and PCB studies are summarized in Figure via injections. Both routs named here are generic as oral administration may be performed by oral gavage or by addition of the substance to food; injections include subcutaneous, intravenous and intraperitoneal and may be further divided by point of injection. Each certain type of substance administration has its unique advantages and disadvantages. However the main advantage of all oral routes is that they better mimic natural conditions of exposure  and are less stressful for animals. Oral routes add uncertainty to the estimation of exposure since rate of absorption and transformation of substance in the intestine are often poorly known. On the contrary generic routes via injections allow for better control of the internal dose, especially at low doses. They do not simulate in majority of cases environmental exposures however and are stressful.The two major routes of exposure used in experiments with animals are the oral routes and β = 1.09; p < 0.0001). Surprisingly, only 4 PBDE studies reported using injections. Thus PCB and PBDE studies seem to be at odds with respect to route of exposure.According to the data summarized in Figure Critical analysis of reports of PCB and PBDE toxicity testing in animal models shows that the logistics of toxicological experiments makes animal data difficult to transfer to human studies. Moreover, analysis of the history of animal studies shows that the hindsight offered by PCB experimental history had little impact on experimental toxicology and future investigations into PBDE. Indeed the studies on PBDE display the same flaws as their PCB counterparts, indicating that lessons were not drawn from the history of PCB.One important inconsistency between animal and human research was shown recently in a critical review of PCB experimental studies : the lacFor animal-model data to benefit human studies, our survey highlights that the following important lessons must be drawn.• Intensive animal testing must precede marketing of a new substance or be concomitant to its arrival upon the market in order to avoid contamination of the environment and human population by chemicals with unknown hazardous properties. As research activity is dependent on funding this lesson is relevant not only for toxicologist but for organizations providing financial support.• Toxic effects in experimental studies are obtained at levels of exposure several orders of magnitude higher than exposure levels of the general population, preventing direct transfer of animal results to human studies. Hence, there is a need for toxic-substances testing with doses relevant to human exposures and measurement of internal dose.• There is a need to use animal species with human-like toxicokinetics and physiology of development and pregnancy. Rodents are becoming the sole model for toxicological experiments. Toxic effects investigation, especially in developmental toxicology, should extend to other mammalian species.• For endocrine disruptors, all endocrine glands must be addressed. The role of environmental contaminants in increasingly prevalent endocrine disorders such as childhood obesity and diabetes mellitus is an important research avenue.• According to the existing paradigm, investigation into the most sensitive stages of development occurs in the following sequence: adult animals – neonates – foetuses. However, the reverse sequence would accelerate data accumulation for risk assessment.• Animal experiments specifically designed to uncover outcomes suitable for epidemiological research are needed. There is increasing demand for this information to design human studies.We conclude that poor integration of the human and experimental branches of toxicology can and does hamper use of data obtained in experiments with animal models. Hence, broadening of the dialogue between the various branches of the field of toxicology is needed.ATSDR: US Agency for Toxic Substances and Disease Registry; BDE-47: 2,2',4,4'-tetrabromodiphenyl ether; deca-BDE: deca-bromodiphenyl ether; NOAEL: no observed adverse effect level; octa-BDE: octa-bromodiphenyl ether; PBDE: polybrominated diphenyl ether; PBPK: physiologically-based pharmacokinetic; PCB: polychlorinated biphenyl; PND: postnatal day; PVC: polyvinyl chloride.The authors declare that they have no competing interests.AS has made substantial contributions to conception, design of review, acquisition, analysis and interpretation of data; LT has been involved in drafting the manuscript and revising it critically. Both authors have approved the final version of the manuscript.Includes data  on articles addressing health effects of PCB toxicity in experiments with animal models that were selected according to the criteria described in background.Click here for fileIncludes data  on articles addressing health effects of PBDE toxicity in experiments with animal models that were selected according to the criteria described in background.Click here for file


Desmoglein 1 and 3 are distributed in the outer root sheath (ORS) of the hair follicle. Direct immunofluoresence (DIF) pattern of ORS in cases of pemphigus resembles the DIF pattern of the perilesional skin. We performed a DIF of the anagen and telogen hair ORS in a case of pemphigus and correlated it with the DIF findings of perilesional skin. Telogen hair ORS promises to be a useful tool in performing DIF for the purpose of diagnosis and follow-up in cases of pemphigus Pemphigus is a group of autoimmune blistering disease of the skin and mucosa characterized by antibodies against desmoglein (Dsg) 3 and Dsg 1. The outer root sheath (ORS) of the hair follicle is structurally analogous to epidermal keratinocytes.-4 Dsg 3 A 36-year-old male presented with multiple flaccid blisters and oozy erosions over the scalp, trunk, and oral cavity of 20 days duration. There was no history of similar complaints in the past. On examination, he had severe erosions with oozing over the scalp and patchy hair loss. Flaccid blisters were seen on the trunk and upper limbs. The oral cavity showed erosins. Nikolsky's sign was positive. With the above findings, a clinical diagnosis of pemphigus vulgaris was made. Skin biopsy revealed features consistent with pemphigus vulgaris. DIF of perilesional skin revealed the typical fish net pattern of intercellular immunoglobulin (Ig) G and C3 deposits . TelogenPemphigus is a group of autoimmune blistering disease of the skin and mucosa characterized by antibodies against Dsg 3 and, to a lesser extent, against Dsg 1. DIF of perilesional skin and mucosa has been established as the confirmatory test for diagnosis. DIF in pemphigus shows IgG antibodies deposited in a fish net or chicken wire pattern against Dsg 1 and Dsg 3. The cell adhesion proteins of the desmosome, Dsg and desmocollin are members of the cadherin family of cell adhesion molecules. They are transmembrane proteins that bridge the space between adjacent epithelial cells by way of homophilic binding of their extracellular domains to other desmosomal cadherins on the adjacent cell. Within stratified squamous epithelia, such as the epidermis and ORS, Dsg are generally expressed in a differentiation-zspecific manner. Dsg 1 iset al.[et al.[Immunodeposits specific to pemphigus were previously shown in the ORS and matrix of hair follicle biopsy specimens. Schaereret al. demonstrl.[et al. reportedIn our case, pemphigus-specific DIF pattern was seen in the ORS of telogen hair, which correlated with the DIF findings of anagen and perilesional skin. DIF positivity in the ORS of telogen hair has not been reported. Because telogen hair is rich in Dsg 3, it may act as a good substrate for performing DIF in cases of pemphigus. Telogen hair is readily obtained by gentle pulling or combing the hair and is less painful than plucking. Telogen hair ORS promises to be a useful tool in performing DIF for the purpose of diagnosis and follow-up in cases of pemphigus. For processing the hair as a substrate for DIF, we mounted the hair directly on the slide without sectioning. This method may overcome the technical difficulties encountered during the earlier studies. However,


Book review of "Primate Parasite Ecology: The dynamics and study of host-parasite relationships" by Michael A. Huffman and Colin A. Chapman (Eds.) No one can doubt that disease played a major role in human history and still continues to impact human health. Also, many human diseases, such as HIV, Ebola and malaria, have been acquired from our close primate relatives. The potential transmission of infectious agents from monkeys and apes to humans is why the study of primate parasites is so significant. The present work, which is divided into several Parts, consists of 25 chapters authored by one or more of 62 contributors.Oesophagostomum). This is followed by a discussion on the use of endocrinological analyses to interpret social relationships, anthropogenic disturbances and nutrition of primates. Part 1 ends with a chapter on the use of agent-based modeling to investigate the role played by infectious diseases of primates.Part 1 deals with methods used in studying primate parasite interactions. It begins with a chapter on collecting and diagnosing primate parasites. This is followed with a chapter on extracting and identifying minute nematodes, mostly pin worms, recovered from fecal samples. The next chapter discusses the use of molecular methods for comparing populations of stomach worms , fleas, ticks, leeches and trematodes. Included is American trypanosomiasis or Chagas disease, caused by Trypanosoma cruzi. Reservoir hosts include rodents, but also probably bats since a member of the latter group carried a Trypanosoma very similar to T. cruzi 20-30 million years ago in Hispaniola. Curiously, the authors omitted reports of simian infections by Leishmania, an important human disease in both the New and Old Worlds.The next chapter discusses disease avoidance in gorillas and chimpanzees in relation to social organization. The amount of Pediculus, Pthrius and Pedicinus) as markers of primate evolutionary history. Pinworms, Pneumocystis fungae, Plasmodium malaria and simian foamy virus are other agents that could be used as markers for non-human primate evolution.The following chapter discusses the use of primate sucking lice  of lice on primates. The human body louse and head louse are considered cryptic species and various methods by which they can be distinguished, including molecular, are discussed. The next chapter discusses the prevalence of Pan paniscus) in Congo's Lomako Forest reports protozoan trophozoites, trematodes and nematodes. This is followed by a chapter on habitat disturbance and seasonal fluctuations of lemur parasites (Sifakas) in Madagascar. Tapeworm and nematode populations were higher in Sifakas (Propithecus edwardsi) in disturbed rather than in undisturbed forests. The following chapter questions if climatic differences might influence self-medicative behavior  in gorillas. Apparently this behavior stimulates peristalsis that serves to cleanse the gut of helminths.A chapter on gasterointestinal parasites from fecal samples of bonbos  in Uganda. Results showed no difference in numbers of protozoa and nematodes between large and small monkey troops. The next chapter discussed whether the diet of mountain gorillas in Uganda influenced their nematode and tapeworm parasites. No correlation between parasite load and protein intake was noted, but ingestion of tannin decreased pinworm (Probstmayria sp.) infections in females and juveniles. This Part ends with a discussion on host-parasite dynamics and future areas of study in primate-parasite ecology.Possible differences in the parasite load in wild-feeding and crop raiding baboons were investigated in the next chapter. Significant differences were found regarding some of the parasites. Whether parasites can be a selective force on primate group size is discussed in the following chapter. This hypothesis was tested with red colobus monkeys (This book contains a wealth of information and provides a solid base for future studies of primate-parasite interactions. A higher classification of the primates, down to the species level with those members discussed in the book, would have been a helpful addition.The author declares that he has no competing interests.


Most malaria-endemic countries are implementing a change in anti-malarial drug policy to artemisinin-based combination therapy (ACT). The impact of different drug choices and implementation strategies is uncertain. Data from many epidemiological studies in different levels of malaria endemicity and in areas with the highest prevalence of drug resistance like borders of Thailand are certainly valuable. Formulating an appropriate dynamic data-driven model is a powerful predictive tool for exploring the impact of these strategies quantitatively.A comprehensive model was constructed incorporating important epidemiological and biological factors of human, mosquito, parasite and treatment. The iterative process of developing the model, identifying data needed, and parameterization has been taken to strongly link the model to the empirical evidence. The model provides quantitative measures of outcomes, such as malaria prevalence/incidence and treatment failure, and illustrates the spread of resistance in low and high transmission settings. The model was used to evaluate different anti-malarial policy options focusing on ACT deployment.The model predicts robustly that in low transmission settings drug resistance spreads faster than in high transmission settings, and treatment failure is the main force driving the spread of drug resistance. In low transmission settings, ACT slows the spread of drug resistance to a partner drug, especially at high coverage rates. This effect decreases exponentially with increasing delay in deploying the ACT and decreasing rates of coverage. In the high transmission settings, however, drug resistance is driven by the proportion of the human population with a residual drug level, which gives resistant parasites some survival advantage. The spread of drug resistance could be slowed down by controlling presumptive drug use and avoiding the use of combination therapies containing drugs with mismatched half-lives, together with reducing malaria transmission through vector control measures.This paper has demonstrated the use of a comprehensive mathematical model to describe malaria transmission and the spread of drug resistance. The model is strongly linked to the empirical evidence obtained from extensive data available from various sources. This model can be a useful tool to inform the design of treatment policies, particularly at a time when ACT has been endorsed by WHO as first-line treatment for falciparum malaria worldwide. Plasmodium falciparum malaria in much of the world. The World Health Organization (WHO) now recommends artemisinin-based combination therapy (ACT) as first-line treatment for all falciparum malaria in endemic areas [For the past half-century, the malaria parasites of humans have been under tremendous selection pressure to evolve mechanisms of resistance to the prevailing anti-malarial drugs. Chloroquine and, increasingly, sulphadoxine-pyrimethamine (SP), have become largely ineffective as monotherapy for the treatment of ic areas .in-vivo resistance to artemisinin derivatives has not yet been confirmed, and stable resistance has been very difficult to produce in the laboratory [The artemisinin-based combinations are efficacious, rapidly acting, well-tolerated and safe. They are available in various formulations, which are generally given over three days. The various forms of ACT are effective against both asexual and early sexual parasite stages , and, thboratory . As for boratory .Although malaria-endemic countries are switching to ACT with increasing momentum, even at prices as low as US$1 per dose, it is still too costly for communities and governments in poorer countries (5 – 10 times higher than the prices of chloroquine or SP in Africa ). DoubtsIn the current study, a comprehensive mathematical model describing malaria transmission and evolution of anti-malarial drug resistance is constructed to answer the questions on treatment strategies focusing on the deployment of ACT in different transmission settings.de novo or the initial emergence of resistance, and its subsequent spread. Resistance spreads because of the higher reproductive rate of resistance infections in the presence of anti-malarial drugs. In this paper, the focus is on modeling the spread of resistance assuming that drug resistance has already emerged among the human population. Combinations prevent resistance by preventing de novo emergence. Modeling the de novo emergence of drug resistance is discussed elsewhere [The development of drug resistance is a two-step process, the lsewhere ,10.. A stochastic component of new imported infections (migrant) is added to the model making it more realistic.Transmission and anti-malarial drug resistance are modeled on an age-structured population-based model, where the size and age-structure of the human population were assumed to be constant over time and based on an average African age-structure in-vivo effect of drugs on parasite density can be measured, allowing quantification of the pharmacodynamic properties of anti-malarial drugs [The dynamic of mosquito population was summarized into vectorial capacities (VC) and estimated from several epidemiological studies. It is assumed that all humans are equally attractive to biting mosquitoes. Malaria is transmitted when a susceptible human is bitten by an infected Anopheline mosquito. The rate at which a susceptible person becomes infected or the inoculation rate is a function of contact rate with infective mosquitoes and level of host susceptibility, based on the formula given by Dietz  see equ. By assual drugs . The avetreated and untreated infections. The host susceptibility and the duration of infection for any given age group in any transmission intensity setting are then determined by the shape of the immunity curve. As the shape of the age effect on treatment failure is similar to the relationship between age and severe malaria [The dynamic in human mainly consists of the development of immunity by age and transmission intensity. Making the model data-driven, the parameters for immunity functions and malaria infection in the human host  were obtained from clinical, laboratory and epidemiological studies. Appropriate curve fitting including multiple linear and non-linear regressions was fitted to different data from age-stratified epidemiological studies in areas with different transmission intensities to derive immunity functions of age and EIR  artemisinin or its derivatives, or a completely new drug can also be introduced and used in a combination with drug A, or it can be used as a monotherapy. Resistance can then be tracked for a specified length of 10 years after steady state to gauge the impact on model outcomes over time. The model provides a number of outputs including estimated EIR, proportion of symptomatic infections, proportion of treatment failure, malaria prevalence and percentage of resistant infections. Those relevant to policy, the proportion of infections with resistant parasites, the malaria prevalence, and the incidence of malaria are presented here. The sensitivity of the model was tested in the four baseline scenarios (scenario A – D). The details of fixed and variable parameters with their respective distributions are given in Tables S1 – S6, Additional File At the outset, a human population is assumed to have little or no exposure to malaria and, therefore, the population has no immunity to malaria. Infected mosquitoes bite randomly and infect humans with drug susceptible infections i.e. malaria infections initially are all drug-sensitive and symptomatic humans receive only monotherapy (drug A). As the population becomes exposed to malaria and gains some level of immunity, the model updates the age-stratified immunity of the population according to the Entomological Inoculation Rate (EIR) , low transmission setting with high ACT coverage (scenario B), high transmission setting with low ACT coverage (scenario C) and high transmission with high ACT coverage (scenario D)). The model consistency is expressed as the Coefficient of Variation (CV) i.e. the variations in the model outputs given that there are uncertainties in the input parameter estimated , with low ACT coverage, variations in the estimated prevalence of malaria stay consistently high over time (CV ~ 90%) after the steady state is obtained, while the variation in the estimated resistance falls substantially till year 8 (CV ~ 9%) with resistance approaching fixation at 100% in our 10-year time horizon. In low transmission settings with high ACT coverage, the mean prevalence of malaria stays below 1% over 10 years. Migration plays an important role in sustaining malaria. Without imported cases, malaria is readily eradicated. Mean resistance increases at a slower rate than in a low coverage setting, reaching 80% in year 10. Compared to scenario A, variation in the estimated prevalence is slightly lower (CV ~ 75%) while variation in the rate of resistance is higher (CV > 30%). This indicates some levels of uncertainty in the consequences of deploying a high coverage of ACT on the malaria prevalence and the rate of resistance. Once resistance to the slowly eliminated partner drug has emerged the spread of drug resistance and the malaria prevalence could be slowed down only by deploying ACT at a high coverage rate while the resistance prevalence is still reasonably low.In the low transmission setting, VC was the most influential parameter affecting malaria prevalence (PRCC ~ 0.6), while VC (PRCC ~ 0.7) and the proportion of treated infections (PRCC ~ 0.4) were the most influential parameters affecting the spread of drug resistance.In the high transmission setting (EIR > 100), malaria cannot be eradicated by anti-malarial treatment of symptomatic cases alone because the major transmission reservoir is in asymptomatic persons who do not take anti-malarial drugs. In the high transmission setting with low ACT coverage, malaria prevalence increases from 36% to 44% within 10 years due to the spread of resistance. Resistance spreads more slowly compared to the low transmission setting, reaching 80% in year 10. Variation in estimated prevalence is small (CV < 30%) while variation in the rate of resistance is consistently high (CV > 45%) compared to estimates in the low transmission setting. Both outcomes and their variations are unaltered by deploying a high coverage of ACT. Treatment of symptomatic infections in the high transmission setting has much less effect than in the low transmission setting. Consequently, the spread of drug resistance is driven by the fraction of the population with some residual anti-malarial drug in their blood and not by treatment failure.In the high transmission setting, the parameters influencing malaria prevalence are the characteristics of the infection in immune subjects with untreated infections. These are the parasite biomass (PRCC ~ 0.4), the gametocyte switch rate (PRCC ~ 0.4) and the duration of infection (PRCC ~ 0.3). The proportion of residual drug in the population (PRCC ~ 0.9) is the dominant factor driving the spread of drug resistance in this setting. The strong correlation between the fraction of population with residual drug concentrations and the levels of resistance from this model suggests that controlling the use of presumptive treatment and encouraging the use of combination therapy with matching half-lives to reduce the selective window would slow the spread of resistance down within this setting.In the first scenario, the model is used to predict the impact of varying the timing of switch to a high coverage  by combining an artemisinin derivative with a failing partner drug (e.g. mefloquine), where the timing of the switch is governed by an observed prevalence of resistance to the partner drug in low and high transmission settings Figure  and 3.In the low transmission setting, treatment dependent parameter values are given in Table S8, Additional File de novo resistance selection probability.In the high transmission settings, immunity prevents most acquired infections transmitting . Approximately 94% of all infections are asymptomatic and untreated. In the absence of anti-malarial treatment, the resistant infections have no survival advantage over the sensitive ones, and may have a fitness disadvantage. The main driving force for resistance is created from the selective filter provided by people carrying low residual concentrations of drugs, which protect against the establishment of new sensitive infections but not the resistant ones ,33. WithCombining an artemisinin with a drug to which resistance has arisen delays the spread of resistance in the low transmission setting Figure , but thiIn this scenario, it is assumed that the monotherapy is the artemisinin and that drug resistance emerges to the artemisinin compound, rather than to the partner drug in an ACT (e.g. either piperaquine or lumefantrine), which is assumed to remain effective . In order to make an impact on malaria transmission and resistance, vector control strategies need to be applied to reduce the VC. Reduction in the transmission intensity results in fewer infections, which, as host immunity declines, are more likely to be symptomatic and eventually this makes malaria control by drugs more effective.P. falciparum has been developed. The similarities between this and a prior simulation model by Cross are pronounced [A mathematical model always represents a simplified version of the true biological system. Complexity is traded against robustness. Malaria modeling has proven to be a useful tool for predicting the potential consequences of malaria control strategies ,35. In tonounced . Both moet al. (2008), it was suggested that high level of clinical immunity create ecological refuge for drug-sensitive parasites. This implied that resistance is relatively easier to spread in a low transmission setting compared to a high transmission setting [The model predicts rapid spread of drug resistance in low transmission settings, and slower spread in high transmission settings. This is consistent with epidemiological observations. In low transmission settings a higher proportion of potentially transmissible infections are exposed to anti-malarial drugs and lower immunity increases the individual probability of treatment failure and transmission of resistant parasites. This prediction is also agreed by previous models -41. The  setting . In low Plasmodium falciparum malaria can be eliminated, although micro-heterogeneities in transmission intensity in remote areas will often ensure a protracted "end-game". The impact of ACT on drug resistance in high transmission intensity settings is limited because the majority of population is immune, many infections are asymptomatic, and therefore a smaller proportion of the infections are treated. An important weakness in the understanding of the epidemiology of malaria is the relative contribution of asymptomatic and symptomatic infections to transmission. The smaller the contribution of asymptomatic infections, the greater is the effect of ACT in slowing resistance spread. The main force driving the spread of drug resistance in these circumstances is the chemoprophylactic effect of presumptive therapy, which provides a selective filter for resistant parasites. The model also predicts that at low transmission intensities malaria transmission is readily eradicated without the continued influx of infected migrants. This has important implications for eliminating malaria [In low transmission settings, increasing ACT coverage is essential if the dramatic effects on malaria incidence observed recently in north-west Thailand, KwaZulu Natal and Zanzibar are to be extended to other areas ,43. Plas malaria ,45.The question of whether it is possible to reduce malaria transmission sufficiently to eliminate malaria eventually in high malaria transmission areas remains unresolved . In highA major obstacle to achieving the benefits of high coverage is the current cost of the drugs. The outputs provided by this model constitute a strong argument for a global subsidy to make ACT generally available and affordable in endemic areas. In addition, other interventions to reduce malaria transmission and to control usage of anti-malarial drugs may be required for slowing down the spread of drug resistance in high transmission intensity settings.The spread of resistant parasites presents a very real public health risk and, in the absence of surveillance data, data-driven theoretical models provide the best information to assist policy making. This relatively complex model of malaria transmission and drug resistance provides a good framework for further development of the model to guide decision-making of other public health policies.SP: sulphadoxine – pyrimethamine; ACT: artemisinin combination therapy; GSR: gametocyte switching rate, proportion of asexual parasites committing to sexual stage differentiation; EIR: entomological inoculation rate; VC: vectorial capacity; AIC: the Akaike information criterion; AUCgam: area under the curve of time versus blood gametocyte density; PRR: parasite reduction ratio, fractional reduction in parasitaemia per asexual cycle; LHS: Latin hypercube sampling; CV: coefficient of variation; PRCC: partial rank correlation coefficient; ITN: insecticide-treated bednet.WP developed and programmed the model and co-wrote the paper. SY developed the model, focusing on parameterization and co-wrote the paper. IH provided intellectual guidance on the mathematical modeling. AD provided suggestions on parasite dynamics and edited the paper. ND provided input on model design. NJW conceived of the study, provided overall intellectual guidance and edited the paper.Model formalism.Click here for fileTables of parameters for sensitivity and scenario analyses.Click here for fileSensitivity analysis results.Click here for file


Closed subtalar dislocations associated with talus and navicular fractures are rare injuries. We report on a case of a 43-year-old builder man with medial subtalar dislocation that was further complicated by minimally displaced talar and navicular fractures. Successful closed reduction under general anesthesia was followed by non-weight bearing and ankle immobilization with a below-knee cast for 6 ;weeks. At 3 years post-injury, the subtalar joint was stable, the foot and ankle mobility was in normal limits and the patient could still work as a builder. However, he complained for occasionally mild pain due to the development of post-traumatic arthritis in subtalar and ankle joints. Our search in literature revealed that conservative treatment of all the successfully reduced and minimally displaced subtalar fracture-dislocations has given superior results compared to surgical management. However, even in cases with no or slight fracture displacement, avascular necrosis of the talus or arthritis of the surrounding joints can compromise the final functional outcome. Subtalar dislocation is a rare ankle injury. Although it can occur in any direction, medial dislocation is the most common injury pattern . The lesWe report a case of closed subtalar dislocation with concomitant and ipsilateral talus and navicular fractures. At 3 years postoperatively, the foot scored well in terms of stability and range of motion but post-traumatic arthritis compromised the final result. We also present our results from the review of English literature regarding the incidence and the main characteristics of the injury, as well as the outcome of the applied treatment options.The Hospital’s Scientific Research Board approved this study, which was conducted in accordance with the World Medical Association Declaration of Helsinki of 1975 as revised in 2000. The patient was informed about his participation in the study and gave informed consent.A 43-year-old Greek male builder admitted to the Accident and Emergency Department of the Hospital due to fall from a height of about 2.5 m. The patient complained of severe right ankle pain and inability to bear any weight on his extremity. In clinical examination the ankle was substantially swollen and ecchymotic, while the talonavicular and medial subtalar joints were very tender and painful to palpation. However, no neurovascular or tendon disturbances were identified. Both oblique and anteroposterior radiographs showed medial displacement of the midfoot without any evidence of bone fracture.  and b.Under general anesthesia, the subtalar dislocation was successfully reduced with manual pressure on the head of the talus and traction, plantar flexion and pronation of the forefoot. The knee was kept flexed throughout the relocation process for eliminating the tension of the soleus muscle. Afterwards, the quality of the reduction and the stability of the subtalar joint were evaluated under fluoroscopy. As no signs of anteroposterior or mediolateral instability were recognized, the ankle was immobilized in a short leg non-weight-bearing cast for 6 weeks. A post-reduction compute tomography (CT) scan was also performed to confirm the anatomic reduction of the subtalar joint dislocation and reveal any potential fractures. The CT scan showed a nondisplaced fracture of the talus body, an osteochondral fracture of the head of the talus and a nondisplaced navicular fracture . Due to After cast removal, an intensive foot and ankle physiotherapy program was commenced for restoring the foot and ankle mobility and preventing stiffness. The patient was limited to partial weight bearing for another 2 weeks and after that time he progressed to weight bearing as tolerated.At 3 year follow up examination, the patient performed well in terms of foot and ankle range of motion. No signs of instability were identified. The good clinical result was also illustrated from the AOFAS , ankle hClosed subtalar dislocations may be associated with concomitant intra-articular fractures of the osseous elements of foot and ankle . CombineOur search in English literature revealed 26 published studies with 328 patients suffering from closed subtalar dislocations . In the Pure dislocations seem to have a more favorable prognosis compared to combined injuries and associated fractures ,13. In aAccording to the published studies, there is no general agreement regarding the proper immobilization period after successful reduction of the subtalar dislocation. DeLee and Curtis , found tThe direction of dislocation seems to play also a significant role in the final functional outcome. Medial subtalar dislocations usually have shown good results when treated conservatively, while lateral dislocations have been associated with important disability -28. HoweIn the current case report, we emphasize that even careful scrutinize of the initial radiographs could not be always adequate for identifying any associated fractures. In this case, the clinical result may be complicated by stiffness and painful deformity. Therefore, we advocate further examination with CT scan after reduction of the dislocation. However, and despite the meticulous evaluation of the injured area, the current treatment methods cannot preclude the possibility of avascular necrosis of the talus and post-traumatic arthritis. These findings, which were also evident in our case, underline the severity of the injury and the magnitude of damage in both bone and soft tissue structures.In conclusion, additional radiologic examination may be of clear benefit in all the subtalar dislocations. Conservative treatment remains the optimal treatment choice for the all the dislocation types without concomitant displaced fractures. However, the long-term performance of the foot is unpredictable due to the risks of avascular necrosis of the talus and degenerative arthritis.


Lower-than-expected incidence of HIV undermines sample size calculations and compromises the power of a HIV prevention trial. We evaluated the effectiveness of interim monitoring of HIV infection rates and on-going modification of recruitment strategies to enroll women at higher risk of HIV in the Cellulose Sulfate Phase III study in Nigeria.We analyzed prevalence and incidence of HIV and other sexually transmitted infections, demographic and sexual behavior characteristics aggregated over the treatment groups on a quarterly basis. The site investigators were advised on their recruitment strategies based on the findings of the interim analyses.A total of 3619 women were screened and 1644 enrolled at the Ikeja and Apapa clinics in Lagos, and at the Central and Peripheral clinics in Port Harcourt. Twelve months after study initiation, the overall incidence of HIV was less than one-third of the pre-study assumption, with rates of HIV that varied substantially between clinics. Due to the low prevalence and incidence rates of HIV, it was decided to close the Ikeja clinic in Lagos and to find new catchment areas in Port Harcourt. This strategy was associated with an almost two-fold increase in observed HIV incidence during the second year of the study.Given the difficulties in estimating HIV incidence, a close monitoring of HIV prevalence and incidence rates during a trial is warranted. The on-going modification of recruitment strategies based on the regular analysis of HIV rates appeared to be an efficient method for targeting populations at greatest risk of HIV infection and increasing study power in the Nigeria trial.http://clinicaltrials.gov/ct2/show/NCT00120770The trial was registered with the ClinicalTrials.gov registry under #NCT00120770  Lower-than-expected incidence of HIV in a HIV prevention trial may undermine sample size calculations and compromise study power . Even ifWe conducted a trial to evaluate the efficacy of cellulose sulfate (CS) for preventing HIV in Nigeria. In designing our trial, we based our estimate of HIV incidence on the national HIV prevalence in Nigeria reported two years before study initiation -6, and oWe conducted a Phase III, randomized, placebo-controlled trial in Lagos and Port Harcourt, Nigeria between November 2004 and March 2007. Three Institutional Review Boards approved the study: those of the College of Medicine, University of Lagos; the University of Port Harcourt Teaching Hospital; and Family Health International. All participants signed written informed consent forms before enrollment. The study was monitored by a Data Monitoring Committee.Historical data were used to justify our sample size calculations. Roddy et al.  reportedThe admission criteria and study procedures for this study have been described elsewhere . BrieflyStudy data were collected at the sites and entered by local staff into FHI's database. Blinded datasets were used to assess recruitment strategies one year after study initiation and quarterly, thereafter. We assessed the following parameters, aggregated over the treatment groups: number of screened and enrolled participants, prevalence and incidence of HIV and other sexually transmitted infections (STIs) , demographic characteristics and self-reported sexual behavior. HIV/STI prevalence was defined as a proportion of infected participants among women screened for the study. HIV/STI incidence was defined as the rate of new infections in the study. The site investigators were advised on their recruitment strategies based on the findings of the interim analyses.A total of four such interim analyses were conducted between the initiation of the study in November 2004 and its closure in January 2007: on January 17, 2006 (i.e. approximately one year after study initiation); May 02, 2006; July 31, 2006; and November 21, 2006. The first review demonstrated that the overall incidence of HIV was less than one-third of the pre-study estimate . The observed correlation between risk of HIV and study retention suggested that demographics played a major role in loss to follow-up. We compromised our retention rates by recruiting young women at highest risk of HIV infection, residential mobility, and poor compliance with the protocol procedures. While the problem of lower-than-expected incidence can be solved, among other means, by increasing sample size without threatening validity of the results, the consequences of poor retention on interpretation of the data are difficult to overcome. Difficult and prolonged enrollment as well as potential detriment to study retention are serious limitations of conducting a prevention trial among high-risk populations in a low-prevalence country and should be taken into careful consideration before choosing a country and/or site for future HIV-prevention trials.The observed inverse association between the prevalence of HIV and self-reported measures of sexual activity among the two clinics in Port Harcourt and the Apapa clinic in Lagos could have several explanations. Additional information collected informally by the site investigators in Port Harcourt suggested that recruitment in brothel-like structures and hotels, in many of which the use of condoms was mandatory, was one possible reason for the low HIV rates despite high sexual activity at this site. Seemingly, women in these hotels practiced safe sex and, as a result, were not at high risk of HIV in spite of their high level of sexual activity. However, the self-reported data on condom use does not support this speculation Table . AnotherWhile the interim data monitoring and on-going modification of recruitment strategies appeared to be successful in increasing the overall incidence of HIV, the early closure of the CS trial in Nigeria limited our ability to thoroughly evaluate the effectiveness of this approach. Clearly, the closure of the Ikeja clinic in Lagos was the single most important contributing factor in the increase of the observed overall HIV incidence. The effect would have been more profound if this decision had been made sooner. At the same time it is unclear to what extent the modification of recruitment strategies in Port Harcourt contributed to the increase of the observed overall HIV incidence, or if it would have resulted in further substantial increase if the trial had continued as planned.In planning future HIV prevention trials, researchers should use all available means of accurate incidence estimation and, if possible, measurement of HIV incidence in a potential study population. However, given the limitations of the existing methods, a close monitoring of HIV prevalence and incidence rates during the trial seems prudent. The on-going modification of recruitment strategies based on the regular analysis of HIV rates, although not without limitations, appeared to be an efficient method for targeting populations at greatest risk of HIV infection in Nigeria. Direct access to study data and early initiation of regular interim monitoring are important for producing measurable results within a limited time frame.The authors declare that they have no competing interests.VH designed the study, provided overall supervision of its implementation and wrote the paper. FO OKO implemented the study. NM JUO SO acquired and facilitated management of the data. VH FO OKO CW analyzed and interpreted the data. FO OKO NM CW critically revised the paper for important intellectual content. All authors reviewed, approved and take responsibility for the manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2288/9/44/prepub


There is an important global need to improve early detection of oral cancer. Recent reports suggest that optical imaging technologies can aid in the identification of neoplastic lesions in the oral cavity; however, there is little data evaluating the use of optical imaging modalities in resource limited settings where oral cancer impacts patients disproportionately. In this article, we evaluate a simple, low-cost optical imaging system that is designed for early detection of oral cancer in resource limited settings. We report results of a clinical study conducted at Tata Memorial Hospital (TMH) in Mumbai, India using this system as a tool to improve detection of oral cancer and its precursors.Reflectance images with white light illumination and fluorescence images with 455 nm excitation were obtained from 261 sites in the oral cavity from 76 patients and 90 sites in the oral cavity from 33 normal volunteers. Quantitative image features were used to develop classification algorithms to identify neoplastic tissue, using clinical diagnosis of expert observers as the gold standard.Using the ratio of red to green autofluorescence, the algorithm identified tissues judged clinically to be cancer or clinically suspicious for neoplasia with a sensitivity of 90% and a specificity of 87%.Results suggest that the performance of this simple, objective low-cost system has potential to improve oral screening efforts, especially in low-resource settings. Oral cancer is a major health problem worldwide, causing over 127,000 deaths each year . PatientNo satisfactory mechanism exists currently to screen and detect early neoplastic changes of the oral cavity in the general population. Possible explanations include: 1) There is limited public awareness and insufficient education of health care workers about oral cancer risk factors, signs and symptoms. 2) Detection relies heavily on clinical experience at recognition of suspicious lesions during physical examination, with variable effectiveness ,5. It ca® [in situ, or invasive carcinoma, using histology as the gold standard. An important finding was the ability of fluorescence visualization to aid clinicians in identifying early neoplastic lesions that were initially missed during traditional white light examination (WLE) [Recent advances in optical imaging have the potential to improve early detection of oral cancer and its precursors. Several groups have demonstrated that imaging systems that record the spatial distribution of tissue fluorescence at specific excitation/emission wavelength combinations can be used to survey large areas of oral cavity mucosa to non-invasively detect early changes associated with oral cancer in real-time ,7-12. La® . The syson (WLE) .To address the need for objective image interpretation, Roblyer recently described a multimodal digital microscope to obtain digital images of oral tissue fluorescence and reflectance and evaluated the ability of objective image analysis techniques to recognize OPLs and early oral cancer. Using 405 nm excited fluorescence images, algorithms could detect OPLs and oral cancer with a sensitivity of 94% and specificity of 87% in 64 patients . The resWhile digital image analysis can provide more objective interpretation, lower cost devices are needed for use in developing countries. To address the need for low-cost imaging, Rahman recently developed a multi-modal imaging system for screening and detection of oral cancer in high-risk populations in low-resource and remote settings . This poThe portable imaging system used in this study consisted of a modified commercial headlamp system; details of the device have been described previously . BrieflyThe study was conducted at Tata Memorial Hospital (TMH) in Mumbai, India. Patients who were referred to the Cancer Prevention Clinic at Tata Memorial Hospital because of suspicious oral lesions or were waiting for head & neck surgery in the hospital ward were recruited to participate in the study. In addition to patients, healthy volunteers with and without a history of using tobacco were recruited to participate in the study. The clinical study was reviewed and approved by the Hospital Ethics Committee (HEC) at TMH and the image analysis study was reviewed and approved by the Institutional Review Board at Rice University. Written informed consent was obtained from each subject enrolled in the study.In vivo imaging measurements from subjects were obtained in the Cancer Prevention Clinic. All measurements were taken in a darkened room to avoid room light interference. The imaging system was positioned approximately 20 cm away from the subjects. Reflectance image exposure was a few milliseconds while fluorescence image exposure was approximately 500 milliseconds.A head & neck specialist at the clinic assessed each participating patient by conducting a conventional examination of the oral cavity. Initial clinical impression of each site as normal or abnormal was noted. In addition, the presence of either melanosis - darkly pigmented lesions - or oral submucous fibrosis - rigid, fibrotic white lesions - was noted if visible. After clinical examination, digital reflectance and fluorescence images were obtained from clinically abnormal sites and contralateral clinically normal sites. Images were also obtained from the lateral border of the tongue, the buccal mucosa, and the lip of each subject whenever these sites were accessible. A quality control check was performed on all images before further analysis. Sites with poor image quality (e.g. out-of-focus images) were excluded from analysis.For sites with an initial clinical impression of abnormal, the white light reflectance images were reviewed by three expert observers who were blinded to the fluorescence images . At each site, the observer assigned a single clinical impression of 'Normal', 'Low Risk for Neoplasia', 'High Risk for Neoplasia', or 'Cancer'. Consensus clinical impression was used to determine the final diagnostic category for each site imaged. In cases where the impression of one of the expert observers differed from the other two, the clinical impression assigned by two of the three observers was used as the consensus. Measurements in which all three observers disagreed on the clinical impression were excluded from the analysis; a total of four sites were excluded for this reason. Sites with an initial clinical impression of normal were categorized with a diagnosis of 'Normal'. Performances of algorithms based on features of digital optical image analysis are reported relative to this consensus clinical impression.White light reflectance images of each site were first examined; if the area was clinically abnormal, a region of interest (ROI) corresponding to the lesion was defined. If the area was clinically normal, a representative ROI was selected from the white light reflectance image. The same ROI was identified in each color fluorescence image of that site, and quantitative image features were calculated for each ROI.Reflectance and fluorescence images were analyzed to yield possible features for use in classification algorithms. The following metrics were generated for ROIs corresponding to lesions and contralateral normal measurements: the average intensity in the red, green and blue (RGB) channels, average values of the ratios of the R/G, R/B and B/G intensities, the average intensity following grayscale conversion, and the standard deviation of the RGB and grayscale intensity values. In addition, for each ROI corresponding to a clinically abnormal site, we calculated the ratio of the metric for the lesion relative to that measured from the contralateral normal ROI in the same patient. We refer to these metrics as 'normalized ratios'. For measurements from clinically normal sites, normalized ratios were obtained by dividing each ROI in two and calculating the ratio of the metrics from the two resulting regions.We explored which of these features provided the best separation between non-neoplastic oral mucosa and neoplastic oral mucosa. For calculation of sensitivity and specificity, sites with a diagnosis of 'Cancer' or 'High Risk' were considered to be neoplastic, while sites with a clinical diagnosis of 'Normal' or 'Low Risk' were considered to be non-neoplastic. Prior to feature selection, sites with a clinical descriptor of melanosis were excluded from the data set. Binary classification algorithms were developed using linear discriminant analysis with a single image feature as input. The same clinical dataset was used to both develop the algorithm and to assess classification accuracy. For each image feature, diagnostic performance was assessed as the threshold was varied from the minimum to the maximum of its value to generate a receiver operating characteristic (ROC) curve. Classification performance measures, such as the area under the receiver operating curve (AUC), sensitivity and specificity at the Q-point, were calculated for each of the input metrics using consensus clinical impression as the gold standard.Images from a total of 351 different sites were included in the analysis ; Table Figure Figure This pilot study demonstrates that objective analysis of fluorescence images obtained with a low-cost imaging system can classify sites as neoplastic or non-neoplastic with high sensitivity and specificity relative to the gold standard of consensus clinical impression. The performance of this low-cost, objective system compares favorably to results reported for pilot studies of other optical imaging systems. A recent review by De Veld summarizes several clinical studies of optical imaging with qualitative image analysis for detection of oral neoplasia and reports sensitivity ranging from 63% to 100% and specificity from 79% to 96% . More reIt should be noted that most studies of optical imaging based adjunctive techniques for oral cancer detection have been carried out in high prevalence populations, and recent reviews stress the need for randomized controlled studies in low prevalence populations ,16. To bThe optical characteristics of oral lesions found in this South Asian population are similar to those in other studies. Our finding of decreased fluorescence associated with neoplastic lesions is consistent with reports in the literature. This loss of autofluorescence has been attributed to a decrease in collagen cross-links associated with neoplastic transformation . Our resIn addition, we found the normalized red to green MFI ratio to be amongst the top three best-performing features. Roblyer also reported that this parameter was the best performing feature for quantitative identification of oral premalignant lesions and oral cancer using a multispectral digital microscope . Figure The ability of fluorescence-based screening aids to differentiate precancerous lesions from benign lesions such as inflammation must also be validated in larger trials and the optical properties of other potentially confounding lesions, which may be population specific, must be characterized. For example, betel quid use is common in south Asia and is associated with a high incidence of OPLs as well as other potentially confounding oral lesions, including melanosis and oral submucous fibrosis (OSF) ,19. A reWe characterized the optical properties of two types of potentially confounding lesions, melanosis and OSF, specific to the geographic region. Melanosis is usually benign and not considered to be precancerous . Our resWhile the sensitivity and specificity reported here are encouraging, there are a number of limitations of this study. First, the same dataset was used both to develop classification algorithms and to assess their performance; in this situation, potential over-training can inflate estimates of sensitivity and specificity. Results must be verified in an independent validation set. Second, the gold standard used to assess algorithm performance was consensus clinical impression; due to resource limitations, histopathologic diagnosis was not available from all sites. Finally, a large number of 'Low Risk' sites were misclassified as neoplastic by the optical algorithms presented here. It is interesting to note that 'Low Risk' sites with consensus among all three expert observers were more likely to be classified by the optical algorithms as non-neoplastic (6/10 = 60%) than were 'Low Risk' sites where only two of the expert observers agreed (13/30 = 43%). Additional studies with histologic endpoints for all sites are required to assess the ability of quantitative optical image analysis to aid in the evaluation of low risk oral lesions.in vivo objectively using the low-cost, portable imaging system. Although further work is needed to address the limitations in this study, results from this pilot study suggest that this simple imaging device can potentially improve oral screening efforts in low-resource settings where clinical expertise and resources are often limited.The clinical study presented here demonstrates the ability to identify neoplastic and non-neoplastic oral tissue Dr. Richards-Kortum serves as an unpaid scientific advisor to Remicalm LLC, holds patents related to optical diagnostic technologies that have been licensed to Remicalm LLC, and holds minority ownership in Remicalm LLC. Dr. Gillenwater holds patents related to optical diagnostic technologies that have been licensed to Remicalm LLC, and serves as an unpaid scientific advisor to Remicalm LLC.MSR participated in the design of the study, carried out the clinical measurements, analyzed data and drafted the manuscript. NI recruited the subjects and provided clinical background for the measurements. DR provided analysis tool to develop classification algorithm. VS provided clinical background for the measurements. RR contributed to conception and design of the study, and provided critical review of the manuscript for important intellectual content. AG conceived of the study, participated in its design and provided clinical background for the measurements. SS participated in coordination and design of the study. PC participated in the design of the study and coordination, and provided clinical background for the measurements. All authors read and approved the final manuscript.