In Pakistan, only 59-73% of children 12-23 months of age are fully immunized. This randomized, controlled trial was conducted to assess the impact of a low-literacy immunization promotion educational intervention for mothers living in low-income communities of Karachi on infant immunization completion rates.≤ 6 weeks, were enrolled and randomized into either the intervention or control arm between August - November 2008. The intervention, administered by trained community health workers, consisted of three targeted pictorial messages regarding vaccines. The control group received general health promotion messages based on Pakistan's Lady Health Worker program curriculum. Assessment of DPT/Hepatitis B vaccine completion (3 doses) was conducted 4-months after enrollment. A Poisson regression model was used to estimate effect of the intervention. The multivariable Poisson regression model included maternal education, paternal occupation, ownership of home, cooking fuel used at home, place of residence, the child's immunization status at enrollment, and mother's perception about the impact of immunization on child's health.Three hundred and sixty-six mother-infant pairs, with infants aged Baseline characteristics among the two groups were similar. At 4 month assessment, among 179 mother-infant pairs in the intervention group, 129 (72.1%) had received all 3 doses of DPT/Hepatitis B vaccine, whereas in the control group 92/178 (51.7%) had received all 3 doses. Multivariable analysis revealed a significant improvement of 39%  in DPT-3/Hepatitis B completion rates in the intervention group.A simple educational intervention designed for low-literate populations, improved DPT-3/Hepatitis B vaccine completion rates by 39%. These findings have important implications for improving routine immunization rates in Pakistan. Haemophilus influenzae type b vaccine to be administered with the three doses of DPT/Hepatitis B vaccines. Despite recent efforts, immunization coverage rates in Pakistan remain low, with 59-73% of children aged 12 - 23 months receiving all three doses of DPT/Hepatitis B vaccine [Vaccinating infants against childhood communicable diseases is one of the most cost-effective public health interventions worldwide . PakistaMany studies have looked at factors that affect immunization completion rates. Low parental, specifically maternal literacy and knowledge regarding vaccines and immunization schedule, poor socioeconomic status, and residence in rural areas are associated with low immunization coverage -12. HealIncreasing health awareness, knowledge about diseases, and their prevention or management has successfully improved many different health outcomes in high-income countries, especially among less literate populations -16. EducTo our knowledge, no study has looked at the impact of home-based vaccine promotion education among a population of mothers of newborns at high risk for not seeking immunization services for their children. Our study aims to close this gap. The main objective of this study was to assess the effect of short, home-based information sessions on importance of vaccines on DPT-3/Hepatitis B immunization rates in low-income urban and peri-urban communities in Karachi, Pakistan known for very low demand and care-seeking for vaccination services.This was a multi-site community-based, randomized controlled educational intervention trial conducted at five low-income sites in Karachi. Among these, one community was urban, whereas the other four were peri-urban, located about 45 minutes travel outside of Karachi. The population in the study areas has low literacy, with only 24% of the population being literate. The total combined population of all five study sites is approximately 260,000, with high infant and maternal mortality rates. The major income generating activities include fishing and livestock rearing, or employment in local small industries (garment and leather).The Department of Pediatrics and Child Health, Aga Khan University has well-established household-based surveillance for pregnancy and neonatal outcomes in these areas. A demographic surveillance round of the entire area is completed every three months. All pregnant women identified during this surveillance are visited frequently around the time of birth so that new births can be captured.All mothers living in the study areas, and having a live child ≤ 6 weeks old, were eligible to be enrolled in the study. Twin births, infants > 6 weeks of age, or infants born to mothers living outside the study surveillance areas were excluded. The cutoff of 6 weeks was used to ensure that the intervention was implemented before the first dose of DPT/Hepatitis B came due.Mothers of possibly eligible infants were identified through computerized surveillance databases of pregnant women and newborns maintained at each site. Families were approached with the help of local women, trained as community health workers (CHWs). The CHWs also obtained verbal consent from the mother of each eligible infant. The study protocol was approved by the Ethical Review Committee of the Aga Khan University. Informed consent was obtained from each participant at enrollment, and no breaches of confidentiality occurred.Each mother-infant pair, who consented to participate in the study, was assigned a unique study identification number. Information on household demographics and socio-economic status was collected using a pre-tested structured questionnaire. Data collected on the infant included age, sex, place of birth, and health status. The baseline interview also recorded mother's knowledge and beliefs about vaccines. A follow-up questionnaire was used to assess the outcome. Subjects were enrolled from August 2008 to November 2008. Study participants were followed up for assessment of outcome from December 2008 to March 2009, with each individual mother-infant pair approached four months after the educational intervention session.Randomization lists, stratified for each of the five enrollment sites were generated by a computer and provided to the CHWs Upon consent, mother-infant pairs were assigned either to intervention or control arms through block randomization (n = 4), according to the computer-generated list. As the intervention was educational, blinding of study staff and participants was not possible. Outcome assessment was done by an investigator (BH) at each participant's house, four months after initial enrollment. The investigator was blinded to the exposure status of participants.To address the needs of low literacy populations, easy-to-understand pictorial cards, using very simple language, to convey three key messages as part of the educational intervention were designed. The first key message highlighted how vaccines save children's lives. The second message provided logistic information about the address and location of the local vaccination centers. The third key message emphasized the significance of retaining immunization cards, and the role they could play at the time of the child's school admissions. A copy of these pictorial messages was left with the mother. These messages took about 5 minutes to impart, and were given by the trained CHWs to each participant at their household.The control group verbally received the general health promotion messages adapted from the curricula developed by the Pakistan Ministry of Health for the Lady Health Worker Program. These messages included information on hand-washing, breast-feeding, clean water, benefits of using oral rehydration solutions during diarrhea, bringing the infant to nearby health center when there are symptoms of acute respiratory illnesses, importance of antenatal check-ups for mothers, and some general information on vaccines. These messages were also given by trained CHWs. The length of each educational session in the control group was approximately 10-15 minutes.The study outcome in each study group was the immunization status of DPT-3/Hepatitis B at 4 months after enrollment (4 to 5 months of infant's age). Immunization rates of DPT-3/Hepatitis B vaccines for intervention and control groups were assessed by an investigator, and were divided into two categories:1) Infants receiving all three doses of DPT/Hepatitis B vaccines (assessed through vaccination cards) were considered "DPT-3/Hepatitis B fully immunized".2) Infants missing any dose of DPT/Hepatitis B or who had lost their vaccination cards were termed"DPT-3/Hepatitis B non-immunized".A participant was considered to be "DPT-3/Hepatitis B fully immunized" only if the mother/caretaker of the child was able to produce an EPI-issued or another health facility-issued vaccination card. Verbal responses of mothers regarding vaccine receipt without documentation on a vaccination card were not considered satisfactory evidence of their infant being fully immunized.We assumed a DPT-3/Hepatitis B immunization rate of 55% in the control group, and hypothesized a difference of 15% in the immunization rates between the intervention and control group. With 80% power and α = 0.05, we estimated a sample size of 163 in each arm. Adjusting for possible lost to follow-up, we enrolled 183 mother-infants pairs in each study group.Statistical analysis was performed using SAS Version 9.2 . Baseline characteristics of study participants were compared using proportions. Unadjusted risk ratio (RR) and 95% confidence interval (CI) were estimated for the study outcome (DPT-3/Hepatitis B fully immunized) using bivariate Poisson regression ,20. A muA total of 1157 mother-infant pairs were identified from surveillance databases at the five community sites were approached, and assessed for eligibility. Among these, 479 (41.4%) did not meet inclusion criteria, whereas 312 (27%) declined participation in the study . Adjusting for this variable did not change the effect estimate  Table . Place oThe number needed to treat (NNT) in order to increase the completion of DPT-3/Hepatitis B immunization by 1 child was also calculated. An estimated 5 mothers need to be educated in order to have one more child complete his/her DPT-3/Hepatitis B vaccinations.We also assessed if our results were subject to misclassification bias due to the requirement of documentation of vaccine receipt through vaccination cards for the infant to be classified as fully immunized at outcome assessment, and those without vaccination card as not fully immunized. There were 10 cases (3 in the intervention group and 7 in the control group) that could have been misclassified as "DPT-3/Hepatitis B non-immunized" due to lack of a vaccination card, but whose mothers recalled receipt of all three doses. Including these 10 children in the "DPT-3/Hepatitis B fully immunized" group, 132 (73.7%) infants in the intervention group had completed primary immunization with three doses of DPT and Hepatitis B vaccine, compared to 99 (55.6%) in the control group. Therefore, DPT-3/Hepatitis B immunization rates in the intervention group were improved by 33% . In the multivariable model, the child's immunization status at enrollment was the only variable significantly associated with the study outcome (p < 0.05). After adjusting for it, DPT-3/Hepatitis B immunization rates in the intervention group were improved by 32% .This study demonstrates that providing vaccine-related targeted education to mothers at home is an effective and practical strategy to improve childhood immunization rates in low literacy settings such as ours. In this randomized controlled trial, a significant improvement in infant DPT-3/Hepatitis B vaccine immunization rates was observed in the group of mothers who received home-based education on the importance of vaccines, compared to those who received standard health promotion messages only.In low-income countries, efforts to improve infant vaccination completion rates have focused primarily on supply and/or provider factors, with little focus on creating demand for infant immunization services. The major thrust of the supply-side interventions to improve vaccination rates has been through mass immunization campaigns. These campaigns have been successful in improving vaccine coverage rates . HoweverEducational interventions have been successful in raising awareness regarding vaccine and increasing demand. Jacobson et al  were sucThe success of educational interventions in modifying health-seeking behavior may also be attributed to the focused nature of the interventions. This is certainly true in our study. The intervention group received a 5-minute educational session, focusing on the importance of immunization for a child's health. The control group, on the other hand, received a 10-15 minute verbal session on general child health promotion. Therefore, the group receiving the focused message may have been more likely to understand and retain its content, and modify their behavior, compared to the control group who may have had "information overload".We observed that maternal knowledge/perception regarding importance of vaccines was significantly associated with higher DPT-3/Hepatitis B immunization rates . Our results are consistent with findings of other studies [It is worth noting that even with the educational intervention specific to vaccines, only 72% of infants were fully immunized in the intervention group. This is because our study included very low-income, low-literacy populations of Sindh province where baseline immunization rates are 48% . The natOur study also has a few limitations. First, the third key message provided education on retaining vaccination cards. Therefore, mothers in the intervention group were 17% more likely to save the card and provide proof of vaccination for outcome assessment. However, as shown above, using the stringent proof-of-vaccination via card to determine outcome did not bias our results significantly if infants with maternal recall of vaccine receipt were also included as fully immunized. Including these infants as fully immunized, DPT-3/Hepatitis B immunization rates in the intervention group were still 18 percentage points higher than the control group.A second limitation is the lack of blinding of CHWs and participants as the intervention was educational in nature. However, the investigator (BH) assessing the outcome four months after the intervention was administered was blinded to the exposure status of the study participants. Furthermore, chances of spillover effect, or contamination between the intervention and control arms were minimized by choosing mother-infant pairs from five different communities in Karachi, lowering the probability that households participating in our study with an eligible newborn would be located close to each other. We also observed a trend for mothers in the intervention group to be more educated compared to those in the control group (34% vs. 25%). However, this difference was not statistically significant and other measures of parental knowledge about vaccines did not favor the control group. Our study also had a high refusal rate (27%) which may have excluded participants less likely to accept vaccines from the trial. However, the most common stated reason for refusal was absence of the child's father when study staff visited the household for initial recruitment.Our educational intervention has the potential to be cost-effective. The cost of the intervention per CHW was estimated to be Pakistan Rs. 80 ($1). This includes the cost of laminated colored pictorial cards used by the CHWs to educate the mothers in the intervention group, as well as pamphlets of the pictorial messages left at each participant's house. We also estimated the cost of scaling-up this intervention nationally, through the Lady Health Worker Program. Given that there are 100,000 lady health workers working all over Pakistan, we estimate that the cost of the national scale-up will be approximately $200,000 for the national program .This study offers firm evidence that providing home-based focused education to mothers regarding the importance of vaccines, through pictorial messages using very simple language, is effective in improving infant immunization rates in low-income and low-literacy populations. Our trial intervention offers novel options to the current vaccine coverage enhancement efforts in low-income countries like Pakistan. Given the low "number needed to treat" to increase immunization completion by 20%, this intervention may prove to be quite cost-effective. The National Lady Health Worker Program is an ideal platform for building a more focused immunization promotion campaign, similar to what we designed, and drive up the demand for infant immunization services in Pakistan. However, the operational and logistical challenges involved in large-scale implementation of such an intervention need further evaluation.EPI: Expanded Program on Immunization; BCG: Bacillus Calmette-Guérin; OPV: Oral Polio Vaccine; DPT: Diphtheria Pertussis Tetanus; CHW: Community health worker.The authors declare that they have no competing interests.AO provided the design and execution of the data analysis, as well as wrote the manuscript. BH contributed to manuscript writing and supervised field operations. ARS supervised manuscript preparation. AA supervised data analysis. AKMZ contributed to the design of the study, data analysis, and manuscript writing. All authors have read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2458/11/239/prepub


Switchgrass has increasingly been recognized as a dedicated biofuel crop for its broad adaptation to marginal lands and high biomass. However, little is known about the basic biology and the regulatory mechanisms of gene expression in switchgrass, particularly under stress conditions. In this study, we investigated the effect of salt and drought stress on switchgrass germination, growth and the expression of small regulatory RNAs. The results indicate that salt stress had a gradual but significant negative effect on switchgrass growth and development. The germination rate was significantly decreased from 82% for control to 36% under 1% NaCl treatment. However, drought stress had little effect on the germination rate but had a significant effect on the growth of switchgrass under the severest salinity stress. Both salt and drought stresses altered the expression pattern of miRNAs in a dose-dependent manner. However, each miRNA responded to drought stress in a different pattern. Salt and drought stress changed the expression level of miRNAs mainly from 0.9-fold up-regulation to 0.7-fold down-regulation. miRNAs were less sensitive to drought treatment than salinity treatment, as evidenced by the narrow fold change in expression levels. Although the range of change in expression level of miRNAs was similar under salt and drought stress, no miRNAs displayed significant change in expression level under all tested salt conditions. Two miRNAs, miR156 and miR162, showed significantly change in expression level under high drought stress. This suggests that miR156 and miR162 may attribute to the adaption of switchgrass to drought stress and are good candidates for improving switchgrass as a biofuel crop by transgenic technology. Panicum virgatum L.) is a warm-season perennial grass that is native to North America. It has been widely used as a forage crop and thrives well on marginal lands and can tolerate semi-arid conditions. Its broad adaptation and rapid growth rate provide stable and high supply of biomass for biofuel production Switchgrass (MicroRNAs (miRNAs) are an extensive class of newly discovered non-coding small RNAs that regulate gene expression at the post-transcription levels by mRNA cleavage or translation repression Solanum and rice More than 40 miRNA families have been associated with abiotic stress in plants miRNAs in switchgrass have been recently studied using computational and experimental approaches Switchgrass cv Alamo was used in this experiment. Alamo is a lowland cultivar of switchgrass adapted well to the southeastern United States To avoid the individual difference in gene expression, at least four seedlings were used for total RNA extraction. Total RNA was isolated from the grinded samples using the mirVana™ miRNA Isolation Kit  following the user manual. The quantity and quality of total RNA were assessed using a Nanodrop ND-1000  and gel electrophoresis.Twelve miRNAs were selected for this study, which included miR156, miR 157, miR 159, miR 162, miR167, miR169, miR172, miR395, miR396, miR397, miR398, and miR399. A majority of these miRNAs have been reported to play a role under stress conditions in model plant species. Nine of these–miR156, miR167, miR169, miR172, miR395, miR396, miR397, miR398, and miR399–were identified in previous studies Real-time RT-PCR was used to characterize the expression of 12 miRNAs  of single factor was performed to compare the expression difference of miRNAs under different salt and drought treatments.Because there is no reliable reference gene for switchgrass miRNA analysis, to better present the results, the expression levels of each miRNA were calculated using the mean CWe studied several response variables in salt and drought stress treatments: switchgrass germination rate, biomass accumulation, development of leaves and roots, and gene expression dynamics of multiple miRNA genes. Salt stress significantly impacted switchgrass growth . Under nDrought stress did not have a great effect on switchgrass seed germination; however, it did significantly decrease switchgrass biomass p<0.001, . AlthougAll the 12 tested miRNAs were expressed in switchgrass young seedlings, but their expression level varied from each other . Among tSalinity treatment affected the expression of miRNAs in switchgrass young seedlings with a dose-dependent manner . The expAlthough salinity treatment affected the expression of all tested miRNAs, the changes in miRNA expression were small. The highest fold change in expression was miR157 and only 2.8-fold up-regulation was observed under moderate salt treatment. All the other 11 miRNAs only showed less than 0.8-fold up-regulation in expression level and the 0.8-fold up-regulation was observed in miR162 under the most severe salt stress. miR397 was the most down-regulated of all miRNAs evaluated with a change in expression of 0.7-fold at 1% salt treatment; miR157 showed the second greatest change in expression of 0.4-fold down-regulated at 0.1% salt stress.Similar to those effects under salt stress, drought stress also altered the expression level of miRNAs in young switchgrass seedlings, and in a dose-dependent manner . miR156,The expression of miRNAs was less sensitive to drought treatment than salinity treatment evidenced by the narrow fold change in expression levels. The expression change ranged from 0.9-fold up-regulation to 0.6-fold down-regulation after the drought treatments. The expression level of miR162 showed the highest 0.9-fold up-regulation under the highest drought stress; miR156 showed the second largest 0.7-fold change in expression level under 7.5% PEG; all the other 11 miRNAs shows less than 0.6-fold up-regulation in expression level. The largest down-regulated expression, 0.6-fold change, was observed in miR157 at 2.5% PEG and in miR397 at 7.5% PEG.ANOVA analysis indicated that the expression level of two miRNAs, miR156 and miR162, significantly changed under high drought stress (p<0.001). Compared with the expression level under untreated control conditions, miR156 was significantly up-regulated under 7.5% PEG concentration; in contrast, the expression level of miR162 was significantly inhibited by 5% and 7.5% PEG treatment.One reason why switchgrass has gained attention as a dedicated biofuel crop is that it can grow on suboptimal land that has relatively low available water. Our results indicated that salt stress had a significant effect on the germination rate and growth of switchgrass in almost all tested abiotic stresses. Interestingly, drought stress had no obvious effect on the germination rate of switchgrass; the significant effect of drought stress on switchgrass growth was observed only when switchgrass was exposed to high water stress conditions. Barney and colleagues also reported that switchgrass demonstrated great tolerance to drought stress Arabidopsis thaliana and the monocot Oryza sativa. Our results indicate that both salt and drought stresses altered the expression pattern of miRNAs in a dose-dependent manner. Salt and drought stress changed the expression level of miRNAs mainly from 0.9-fold up-regulation to 0.7-fold down-regulation, and drought stress altered the expression of miRNAs from 0.9-fold up-regulation to 0.6-fold down-regulation. Although the range of change in expression level of miRNAs was similar under salt and drought stress, no miRNAs displayed significant change in expression level under all tested salt conditions, however, two miRNAs, miR156 and miR162, showed significantly change in expression level under high drought stress. This suggests that miR156 and miR162 may attribute to the adaption of switchgrass to drought stress and are good candidates for improving switchgrass as a biofuel crop by transgenic technology.miRNAs are an extensive class of newly discovered gene regulators. They have been reported to play important roles under abiotic stress in model plant species. Using qRT-PCR, we studied the expression change of 12 conserved miRNAs in 11 days old switchgrass seedlings exposed to salt and drought stress. Of the 12 miRNAs, 11 have been demonstrated to be involved in salt or drought stress in previous study, eight of these in both the dicot Arabidopsis, rice, and maize led to a prolonged vegetative phase together with the production of significantly higher number of total leaves, which resulted in enhanced biomass accumulation Arabidopsis; miR156 was induced by 1.6-fold by salinity stress miR156 is one class of conserved miRNAs, which play an important role in multiple biological process. By targeting squamosal promoter binding protein-like (SPL) genes, miR156 has been demonstrated to temporally regulate shoot development miR162 has been reported to involve in miRNA biogenesis by negatively regulating dicer-like 1 (DCL1) gene Table S1Primers used in reverse transcription (RT) and qPCR for amplifying 12 miRNAs. The reverse primer is provided by the kit. The nucleotides in green are the same as or complementary to the miRNA sequences. RT and FP in the primer name indicate that the primer is reverse transcription primer or forward PCR primer respectively.(DOC)Click here for additional data file.


With recent improvement in hardware and software techniques, magnetic resonance angiography (MRA) has undergone significant changes in technique and approach. The advent of 3.0 T magnets has allowed reduction in exogenous contrast dose without compromising overall image quality. The use of novel intravascular contrast agents substantially increases the image windows and decreases contrast dose. Additionally, the lower risk and cost in non-contrast enhanced (NCE) MRA has sparked renewed interest in these methods. This article discusses the current state of both contrast-enhanced (CE) and NCE-MRA. New CE-MRA methods take advantage of dose reduction at 3.0 T, novel contrast agents, and parallel imaging methods. The risks of gadolinium-based contrast media, and the NCE-MRA methods of time-of-flight, steady-state free precession, and phase contrast are discussed. Clinical applications for Magnetic Resonance Angiography (MRA) are rapidly expanding as technological advances in both hardware and imaging techniques overcome previous limitations, and the risks from intravenous contrast agents and repeated ionizing radiation exposure become more salient for the clinician and patient . MagnetiAt 3.0T, twice as many protons are aligned with the magnetic field as compared to 1.5T, resulting in a theoretically doubled signal-to-noise ratio (SNR). This gain in SNR can be taken advantage of to increase the spatial resolution, decrease acquisition time, or a combination of the two to achieve the same SNR characteristics as 1.5T in less time. Increased spatial resolution allows for improved visibility of lesions, and faster acquisition times helps reduce motion artifact and decrease breath-holding requirements . AdditioTypically, CE-MRA techniques are used more often than NCE-MRA techniques. Advantages of CE-MRA relative to other MRA techniques, such as time-of-flight (TOF) and phase-contrast (PC), include shorter acquisition times, improved anatomical coverage, and decreased susceptibility to artifacts caused by blood flow and pulsatility. To avoid combined arterial and venous enhancement, shorter acquisition times are necessary to obtain purely "arterial" phase images. This can be done using acquisitions with a parallel imaging or time-resolved techniques. At 3.0T, the gain in SNR can allow higher acceleration factors in parallel imaging to decrease scan times and improve spatial resolution even further .While 3.0T opens many possibilities for the future of MRA, it also carries with it a new set of clinical and technological problems that need to be addressed before gaining widespread use. Pulse sequences that have been optimized for 1.5T may need to be adjusted for 3.0T applications. Additionally, the high magnetic field strength increases energy deposition in the patient and field inhomogeneity, as discussed below.Although gadolinium based agents have an excellent safety record, reports linking gadolinium to nephrogenic systemic fibrosis have sparked renewed interest in "low-dose" CE-MRA and NCE-MRA -8. In adCE-MRA has been established as a non-invasive alternative to conventional angiography in evaluating peripheral vascular disease -12 and cRenal CE-MRA quality at 3.0T has also been evaluated with low-dose Gd. Attenberger et al. demonstrated equal image quality for evaluation of the renal arteries comparing 0.1 mmol/kg of gadobenate dimeglumine at 3.0T with 0.2 mmol/kg of gadobutrol at 1.5T . Kramer Current CE-MRA techniques using conventional Gd-contrast agents are limited by the need to acquire images relatively quickly during the first pass of contrast material through the vessels of interest. Newer, intravascular Gd-based contrast agents can help overcome these limitations. Gadofosveset trisodium, a protein-binding intravascular contrast agent that has recently obtained FDA approval for use in CE-MRA of the aorto-iliac segments, differs from other gadolinium-based contrast media by having a considerably longer intravascular lifetime and higher relaxivity . GadofosParallel imaging further enhances the benefits of 3.0T by undersampling the area of interest as a tradeoff for increased image acquisition speed. Parallel imaging has been applied to CE-MRA to reduce scan time and improve spatial resolution by improving anatomic coverage and removing aliasing artifact with the use of multiple channel coils Figure  19]. Th. Th19]. The stronger magnetic field at 3.0T results in significant challenges and limitations that are yet to be fully overcome. Constructive and destructive interference due to RF field inhomogeneity and increased Specific Absorption Rate (SAR) are major concerns when imaging at 3.0T.RF field inhomogeneity can result in areas of interference and loss of complete anatomic coverage within the image field. At 3.0T, the resonance frequency of protons in water is 128 MHz, double the value in a 1.5T system, which means that the radiofrequency wavelength is halved from 52 cm to 26 cm. This shortened wavelength can span the dimensions of the field of view for abdominal and pelvic imaging, occurring more frequently in persons with a large body habitus . As two RF pulses transfer energy to protons within the patient and ultimately generate heat as a byproduct of energy release. Heat produced within the patient can have detrimental physiologic effects and is carefully monitored within the imaging setting, with current limits of total body heating set by the FDA at 4 W/kg for the whole body over a 15 minute period ,27. SAR The widespread use NCE-MRA has been limited by prolonged acquisition times and motion artifacts that favor CE-MRA. However, several factors have contributed to a renewed interest in NCE-MRA methods, including improvements in MR hardware and software and concerns over the safety of gadolinium-based contrast in high-risk patient groups. The latter is particularly concerning, as patients with moderate to severe renal insufficiency and vascular or metabolic disorders are at risk for developing the debilitating and possibly life-threatening disease of nephrogenic systemic fibrosis (NSF) -8. A recNCE-MRA has been available since the beginning of MR imaging and is routinely used for intracranial imaging. It has also been validated for use in coronary, thoracic, renal and peripheral vascular disease . In a reCoronary MRA has been validated primarily at 1.5T -37, but Time-of-flight (TOF) is the most commonly used NCE MRA technique, especially for peripheral and intracranial applications. TOF relies on the suppression of the background signal by rapid slice-selective radiofrequency excitation pulses that saturate the signal from stationary tissue, resulting in suppressed background signal ,46. BecaTOF acquisitions can be performed using 2D or 3D sampling, with 3D TOF being most commonly used for intracranial vasculature due to the tortuous nature of the arterial tree, tendency for flow within the imaging plane, and need for high spatial resolution . 2D TOF ECG-gating has been successfully applied to CE-MRA techniques in the thoracic aorta, where cardiac motion can result in blurring of the vessel wall in the ascending portion of the aorta . For imaBalanced steady-state free precession (SSFP) techniques are popular for NCE MRA because image contrast is determined by T2/T1 ratios, which leads to inherently bright blood images with little dependence upon blood inflow . Both arIn a retrospective analysis by François et al.  of 23 pa3D SSFP MRA has also been applied to the evaluation of the renal arteries. Maki, et al. compared Arterial spin labeling (ASL) is a technique that can be combined with SSFP to enhance image quality through improved background tissue suppression. Protons upstream of the imaging field are "tagged" with an inversion pulse to provide contrast. Background tissue can be suppressed by subtracting the untagged image from the tagged blood image in two acquisitions  or by apASL is limited by relying on arterial velocity to replace blood in the imaging plane with tagged blood. In peripheral arteries with slower flow, the inflow of tagged blood can approach the T1 of the surrounding tissues, thus eliminating the tagging effect. This can be partially overcome by the multiple, thinner-slab acquisitions, but at the expense of longer imaging times.Phase-Contrast (PC) MRA generates an image by applying a bipolar velocity-encoding gradient during the pulse sequence twice in opposing directions, which results in a net phase change of zero in stationary tissues while applying a phase change in moving blood, producing a signal. Signal strength is proportional to the velocity of moving blood, and the strength of the bipolar flow encoding gradient, which is prescribed by setting the Velocity Encoding (Venc) value. The Venc describes the maximum velocity that can be accurately encoded without aliasing, similar to Doppler velocity measurement. Thus, phase-contrast MRA provides anatomic images of vessels, in addition to hemodynamic data, about flow, unlike TOF and CE-MRA techniques. The intravascular signal loss on 3D PC MRA at and distal to a hemodynamically significant stenosis Figure  is due tpost priori evaluation of flow velocities of any vessel within the imaging volume from the same acquisition. In addition, the 4D PC MRA techniques can be used to qualitatively evaluate the complex flow patterns within the cardiovascular system (Figure Traditionally, PC MRA was performed with three-directional velocity encoding without any temporal information to obtain a "complex-difference" MR angiogram. With this approach, each acquisition was repeated three times with a different velocity-compensation direction and once without flow compensation. Because four acquisitions are needed for 3D PC MRA, the scan times are long and the imaging volume is limited. Parallel imaging techniques  and 3D rm Figure  [65,67-6In summary, recent improvements in MRI hardware and software have lead to dramatic changes in the techniques used for MRA. The greater use of 3.0T scanners for MRA combined with improved parallel imaging methods have brought about a paradigm shift in CE-MRA toward a "less is more" approach. Further reductions in intravenous contrast administration have been made possible with the availability of novel intravascular contrast agents. The other recent major development in MRA has been the renewed use of NCE-MRA methods. Although NCE-MRA methods still require longer scan times than CE-MRA methods, they do offer several advantages over CE-MRA, including reduced risk to patients and lower costs. Interestingly, phase-contrast NCE-MRA methods offer the potential to provide additional hemodynamic information that currently is obtained using invasive methods.The authors declare that they have no competing interests.All authors participated in literature review, manuscript preparation and final approval of submitted manuscript.


The development of chemical sensors for environmental analysis based on fluorescence, phosphorescence and chemiluminescence signals continues to be a dynamic topic within the sensor field. This review covers the fundamentals of this type of sensors, and an update on recent works devoted to quantifying organic pollutants in environmental waters, focusing on advances since about 2005. Among the wide variety of these contaminants, special attention has been paid polycyclic aromatic hydrocarbons, pesticides, explosives and emerging organic pollutants. The potential of coupling optical sensors with multivariate calibration methods in order to improve the selectivity is also discussed. The relevance of applying chemical sensors to environmental measurements lies in the many advantages these devices offer, such as online detection, miniaturization enabling at-site measurements and minimal waste production, which contributes to green chemistry. In the present review we include selected works devoted to the development of both sensors themselves and probes for the study of organic pollutants in environmental waters since 2005.It should be noted that some of the literature terminology related to sensor is ambiguous. A chemical sensor is commonly defined as a device that, as the result of its chemical interaction with an analyte, transforms either qualitative or quantitative chemical information into an analytically useful signal . A sensoChemical sensors are classified according to different criteria ; a usualCommonly, in luminescence sensors the emitted fluorescence, phosphorescence or chemiluminescence signals are measured after the analyte is immobilized in a suitable solid support, giving origin to the expression solid-phase luminescence (SPL) or to its equivalent solid-matrix luminescence (SML). Under certain conditions, these analytical signals can be related to the concentration of analyte in the sample and a quantitative analysis is performed.et al. pyrene (BaP), one of the most carcinogenic PAHs anthracene (DBA) were determined at parts-per-trillion levels in a very interfering environment fluoranthene, benzo[k]fluoranthene and benz[a]anthracene [Very recently, a flow-through optosensor, using silica gel Cthracene . Second-3.−1 for individual and total pesticides, respectively [et al. [Agrochemicals are defined as chemicals, such as fertilizers, hormones, pesticides  which improve the production of crops. Many of these products represent a potential risk for human health and, therefore, worldwide government agencies have manifested their concern, establishing strict maximum limits depending on the corresponding toxicity. The European Union has set drinking water limits of 0.1 and 0.5 ng mLectively . To comp [et al. .3.1.Most research works for residual fungicide detection involve gas and liquid chromatographies, including both conventional and mass spectrometric detection . Howevero-phenylphenol in waters obtained from wells and rivers [o-phenylphenol and thiabendazole, coupling a first-order multivariate approach to a flow-through optosensor system [The coupling of multi-commutation and multi-optosensing was developed for the analysis of fuberidazole and d rivers . The samr system . The selNylon membranes represented a satisfactory phosphorescence probe for thiabendazole , allowinBased on this ability of nylon membranes, it was investigated whether this capability was preserved in nylon powder when used as an optosensor packing. Nylon powder showed outstanding properties as a fluorescence optosensor for the determination of thiabendazole in tap, underground, mineral and river water samples . Nylon p18-membrane surface [The simultaneous determination of carbendazim and thiabendazole was performed using fluorescence excitation-emission matrices obtained after the extraction of the analytes over a C surface . The abi18-bonded phase support and were processed by different algorithms. U-PLS/RBL allowed to reach selectivity using a commercial but non-selective sensing support. The sample frequency, including excitation/emission fluorescence matrix measurements, was 12 samples h−1.The simultaneous determination of thiabendazole and fuberidazole at part-per-billion levels in river, underground, mineral and tap water samples was performed coupling a flow-through optosensor to second-order chemometric analysis . Excitat3.2.et al. have described a fiber-optic fluorescent-based biosensor for the detection of organophosphate insecticides and chemical warfare agents [18 silica gel placed in the flow-cell. The greatest advantage introduced by the developed optosensor is its high throughput and the low cost of reagents in comparison it with batch methods.Viveros e agents . The bioe agents . The insThe insecticide pentachlorophenol was determined in water through the room temperature phosphorescence developed by anchoring an MIP layer on the surface of Mn-doped ZnS quantum dots via a surface molecular imprinting process .3.3.et al. [2O2 flows towards the enzyme region where the chemiluminescence reaction takes place, and the light produced is detected through an optical fiber. The presence of herbicides in the thylakoid samples reduces the hydrogen peroxide measured in a concentration-dependent manner. The system combines the production and detection of hydrogen peroxide in a single flow assay by coupling the individual steps , and a detector module) in a portable device. Preliminary results obtained with real water matrices indicated that the biosensor could be satisfactory applied to real samples.An optical in-house sensor for herbicide detection was developed by Varsami et al. . The sena fluorescence [−1 using chlorophyll fluorescence as the biosensor response signal.A biosensor based on immobilization of microalgal strains in a polycarbonate membrane was constructed for the detection of atrazine, simazine, diuron, isoproturon and paraquat, which affect algae photosynthesis, either increasing or decreasing the chlorophyll rescence . The bioet al. proposed a flow-through immunosensor for the analysis of simazine in fortified river waters [Herranz r waters . The ass18 silica gel filling the flow-cell. The system showed a high throughput, about 35 samples h−1, depending on the injection volume.A flow-through optosensor based on PIF in a micellar medium was developed for the determination of metsulfuron-methyl in river, well and irrigation waters . The mic18 silica support, being HTAC (hexadecyltrimethylammonium chloride) the surfactant that rendered better statistical results. Despite the sensitivity improvement provided by the optosensor, a preconcentration step had to be performed when linuron concentrations below 0.1 μg mL−1 were analyzed.Linuron was determined in both environmental and drinking water samples employing a flow-through PIF optosensor . The pre−1.Isoproturon was analyzed in drinking water using a flow-through fluoroinmunosensor constituted by a sol-gel glass doped with antimonoclonal antibody placed in the flow cell . A compe3.4.A flow-through-phosphorescence optosensor, using a non-ionic polymeric resin (Amberlite XAD-7) as sensor material, was developed for the quantitation of 1-naphthaleneacetic acid in both river and fountain water . The anaThe same research group carried out the determination of 2-naphthoxyacetic acid using both fluorescence and phophorescence flow–through optosensors . While A3.5.18 silica gel) as the flow-through cell [−1 for carbendazim, benomyl and carbofuran, respectively, are obtained using 2 mL of sample.Because different agrochemicals are often applied simultaneously for different purposes, many works are devoted to multiresidue determinations. The fungicides carbendazim and benomyl, and the very toxic insecticide carbofuran were determined in spiked environmental waters using an optosensor implemented with a previous separation of the analytes on a minicolumn placed just before the sensor. The latter was packed with the same solid support  have been determined using an MIP sensor technique ,80. Dete−1 by the Environmental Protection Agency [et al. prepared a cross-linked molecularly imprinted fluorescent conjugated polymer for the detection of TNT and related nitroaromatic compounds [An explosive of great concern is 2,4,6-trinitrotoluene (TNT), which can readily enter groundwater supplies, and has been classified as toxic at concentrations above 2 ng mLn Agency . Li et aompounds . Althouget al. developed a method for detecting TNT in solution and vapor using resonance energy transfer-amplifying fluorescence quenching at the surface of silica nanoparticles as substrate [Gao ubstrate .−1 for TNT and DNT, respectively), future optimizations have been proposed by the authors in order to improve the method sensitivity.A fluorescent-labeled imprinted polymer sensor  was developed to detect aqueous concentrations of TNT and 2,4-dinitrotoluene (DNT) . AlthougA fluorescent sensor was made from commercially available fluorescent polymers coated onto glass beads, and its ability to discriminate explosives and explosive-related compounds in water was tested . The cheQuenching of room-temperature phosphorescence and enhancement of Rayleigh scattering based on Mn-doped ZnS QDs were used as a dual-recognition probe for TNT in water .5.et al. for the determination of 2,6-DNP in water [2,6-Dinitrophenol  is one of the six possible dinitrophenol forms used in the synthesis of dyes, picric acid, picramic acid, wood preservatives, explosives and insecticides, and is a compound of environmental concern . An optiin water . FPVC exThe same group described bifurcated optical fiber chemical sensors  for the −1.An optical inmunosensor to determine BPA in water samples was described . This se−1.A micro-flow immunosensor chip  was conset al. established a fluorescent probe for the qualitative detection of formaldehyde  based on the signal produced by reaction of the analyte and the Nash reagent  embedded in silica gel beads [Zhen el beads . The reaet al. have proposed a flow-through optosensor, based on the luminescence of Eu(III)-TCs complex retained on polymeric Amberlite XAD-4 particles packed in a flow-cell, to determinate four TCs  in bovine milk and water [−1 [Tetracyclines (TCs) are considered as emergent pollutants , and thend water . Recentlater [−1 .−12 mol L−1.A fluorescence resonance energy quenching method using mercaptosuccinic acid-capped CdTe QDs immobilized on silica nanoparticles was developed for the quantification of 1,4-dihydroxybenzene (DHB) in water samples . DHB is et al. [−1 and 10 μg mL−1 for ethylbenzene and xylenes respectively.Sainz Gonzalo et al. ,99 synthet al. developed a polyurethane-based magnetic MIP probe for the optical determination of 1-naphthylamine in tap and mineral water [−1, allowed the determination of 1-naphthylamine in the presence of four structurally related compounds .Valero Navarro al water . The metFinally, a summary of all reviewed works is shown in 6.An important increase in activity for the development of luminescence sensors can be observed during the reviewed period. In general, optosensor methodologies are easily adaptable to green-chemistry principles, and therefore they offer a way to detect/quantify toxic pollutants without contaminating the environment which they want to preserve. Although measurements performed in batch mode are still applied, a significant increase in flow-injection approaches is noticed. The coupling of optosensors to second-order multivariate calibration brought about a significant increase in selectivity, allowing determinations in highly interferent media.


Self-reported anthropometric data are commonly used to estimate prevalence of obesity in population and community-based studies. We aim to: 1) Determine whether survey participants are able and willing to self-report height and weight; 2) Assess the accuracy of self-reported compared to measured anthropometric data in a community-based sample of young people.2. Differences between measured and self-reported values were assessed using paired t-test/Wilcoxon signed ranks test. Accurate report of height and weight were defined as <2cm and <2kg difference between self-report and measured values, respectively. Agreement between classification of overweight/obesity by self-report and measured values was assessed using McNemar’s test.Participants (16–29 years) of a behaviour survey, recruited at a Melbourne music festival (January 2011), were asked to self-report height and weight; researchers independently weighed and measured a sub-sample. Body Mass Index was calculated and overweight/obesity classified as ≥25kg/mOf 1405 survey participants, 82% of males and 72% of females self-reported their height and weight. Among 67 participants who were also independently measured, self-reported height and weight were significantly less than measured height (p=0.01) and weight (p<0.01) among females, but no differences were detected among males. Overall, 52% accurately self-reported height, 30% under-reported, and 18% over-reported; 34% accurately self-reported weight, 52% under-reported and 13% over-reported. More females (70%) than males (35%) under-reported weight (p=0.01). Prevalence of overweight/obesity was 33% based on self-report data and 39% based on measured data (p=0.16).Self-reported measurements may underestimate weight but accurately identified overweight/obesity in the majority of this sample of young people. In Australia, obesity is a national health priority, and approximately one quarter of young adult Australians are overweight or obese . This isBody mass index (BMI) is widely used as a measure of obesity due to its simple derivation from height and weight. Height and weight are commonly self-reported in population health surveys for ease of collection . In contSelf-reported height and weight may be affected by response or recall bias. It is commonly found that weight is underestimated while height is often overestimated -8, leadiIn spite of these findings, there remains a lack of data reporting the willingness and accuracy of young people to self-report height, weight, and derived BMI, particularly in community-based settings. Traditional methods of recruiting young people into population surveys, such as random digit dialling and school-based recruitment, are subject to increasing barriers affecting participation, tracking, and retention, such as high mobility, changes in telephone use and technology, and non-school attendance ,16. CommHere we use participants in a risk behaviour survey to determine the accuracy of self-reported height and weight in Australian 16–29 year olds in a community-based setting. Specifically, the aims of this study were:1) To determine whether young people participating in a risk behaviour survey are able and willing to provide self-reported height and weight data; and2) To assess the accuracy of self-reported height, weight and BMI compared to measured values in a community-based sample of young people.Participants were recruited at the Melbourne Big Day Out (BDO) - one day music festival in January 2011 - as part of an ongoing behavioural surveillance system that has been undertaken at the BDO since 2005 -19. A coThe structure of the market stall set up meant there was one measuring station for height and weight. After completing the questionnaire, participants were invited to have their height and weight measured if approximately three or less participants were waiting to use the measuring station.A core set of questions about drug and alcohol use and sexual risk behaviours is asked annually in the BDO survey ,18. In 2When submitting their completed survey, a subset of individuals was invited to have their height and weight measured by a trained research assistant Figure . As outlTo link measurements to the participants’ surveys, measurements were labelled using either the survey identification number or a “porn star name”, a novel anonymous identifier derived from name of first pet and name of first street , which w2). For participants aged 18 years and older, overweight and obesity were classified using the standard international adult BMI ranges: underweight (BMI <18.5), healthy weight (BMI = 18.5-24.9), overweight (BMI = 25.0-29.9), or obese (BMI >30). [BMI for both self-reported and measured values was calculated as weight (kg) divided by height squared (mMI >30). ,22 For pMI >30).  For the A range of self-reported demographic indicators were assessed: sex ; age ; born in Australia ; area of residence ; living arrangements ; post-high school education ; recreational income . Area of residence was classified from Australian postcodes of residence using the Australian Standard Geographical Classification (ASGC) Remoteness Areas system . RecreatData were entered into a Microsoft Access database and statistical analysis was conducted in Stata version 11 .To assess factors associated with survey participants’ n=1405) ability and willingness to provide self-report height and weight measurements, participants who did and did not self-report height and weight were compared by demographic indicators using chi-square tests of proportion , participants with and without measurements taken were compared using chi-square tests of proportion and Wilcoxon rank-sum test.The final analysis was limited to participants with both self-reported and measured height and weight (n=67) Figure . Accuraci. Test of equality between measured and self-reported mean or median was assessed using a paired t-test or Wilcoxon signed ranks test, respectively, both overall and stratified by sex, age group, and obesity classification categories.ii. Correlation of self-report to measured values was calculated using Pearson correlation coefficient or Spearman rank correlation coefficient according to distribution of both self-reported and measured height, weight and BMI.iii. The proportion of individuals who accurately, under- and over- reported their weight/height was compared using a Fisher’s exact test. Accurate report of weight/height was defined as less than 2kg/2cm absolute difference between self-report and measured weight/height given an acceptable margin of error, based on previous studies . Under-riv. Prevalence of overweight/obesity based on self-report and measured data was compared using two-sided exact McNemar’s test. Misclassification of overweight/obesity was measured in terms of sensitivity and specificity with exact binomial 95% confidence intervals (CI), whereby 100% indicates maximum agreement between self-reported and measured classification.Significance level was 0.05 in all analyses.Ethical approval was granted by the Alfred Hospital Human Research Ethics Committee (number 326/08).In total, 1405 questionnaires were completed  and without (94%) independent anthropometric measurement did not differ by demographic characteristics .The final sample is based on 67 participants with complete self-reported and measured height and weight Figure ; 51% werAs a continuous variable, self-reported and measured height did not significantly differ overall (p=0.06), but mean self-reported height was 2.3 cm less than mean measured height among females (p=0.01) , 30% under-reported, and 18% over-reported their height , 52% under-reported and 13% over-reported their weight  males and 9 (27%) females inaccurately self-reported their height by five centimetres or more (p=0.05), and 12 (35%) males and 5 (15%) females inaccurately self-reported their weight by five kilograms or more (p=0.06). Overweight/obese participants were more likely to misreport their weight by at least 5kg than non-overweight participants .Based on self-report data, 22 (33%) participants were classified as overweight or obese, compared to 26 (39%) participants based on measured data (p=0.29). In total, 59 (88%) were correctly classified. The sensitivity of self-reported data was 77% (95%CI 56%-91%) and specificity was 95% (95%CI 83%-99%).In this study of young people attending a music festival, we determined the feasibility and accuracy of collecting self-reported height and weight. Our results confirm that at a group level, self-report measures in a community-based setting is a useful tool for estimating the prevalence of overweight and obesity, particularly when impractical to take independent measurements.Three-quarters of survey participants provided both self-report height and weight. In the remainder, the majority reported not knowing their height and/or weight, with only a few missing values, although the “don’t know” category might have also included some refusals. Of concern, participants who did not self-report their height or weight were systematically different from those who did; they were more likely to be female, younger, and less educated. Because height and weight measurements were not taken for all participants, we could not determine whether self-reporting height and weight was influenced by bodyweight status. Further research is needed to explore if there are biases in bodyweight status influencing willingness and ability to self-report height and weight in a community-based setting.Self-reported and measured height did not significantly differ, and approximately half of males and females reported their height within two centimetres of measured height. However, females were more likely than males to underreport their height, and approximately one quarter of females misreported their height by more than five centimetres, compared to only nine percent of males. Previous studies have observed over-report of height ,7 or decThe difference between self-reported and measured weight was more pronounced than for height, particularly among females and overweight or obese individuals. Although one third of all individuals reported their weight within two kilograms of measured weight, a notable 35% of males and 15% of females misreported their weight by five or more kilograms. Females were more likely than males to under-report their weight. Our results are consistent with previous studies reporting systematic under-reporting of weight by females and overweight/obese individuals ,12. It hIn this study we found that self-report height and weight is a reasonable predictor of overweight and obesity among young people, particularly when pertaining to population-level applications such as monitoring trends in overweight, program evaluation, and advocacy for funding . NotwithObesity prevention and control is a national priority in Australia, with increasing millions of dollars being invested to its cause . CommuniThis study has a number of limitations. First, the results are based on a convenience-sample and may not be representative of young people in Australia. Second, the sample size for the independent measurement of height and weight was relatively small and may have limited our ability to detect differences and associations with self-reported height and weight. This sample size was limited by the use of only one measuring station, and in the future we recommend more stations are utilised to obtain a larger sample. Third, small differences in self-reported and measured values may be attributable to non-differential measurement bias; multiple researchers were responsible for taking measurements throughout the day and the recruitment day was characterised by high temperatures, reaching up to 40 degrees Celsius. Some participants may have been dehydrated while others were drinking large quantities of water (the study team was distributing water); both factors may have impacted on the accurate measurement of weight. Natural daily weight fluctuation may also partly explain some weight discrepancies; at the festival measurements were taken between 10am-3pm, which may differ to participants’ customary time for weighing themselves. Fourth, selection bias may have been introduced because individuals were not systematically randomised to have their height and weight measured by a researcher; there was potential unrecognised selection bias by the investigators inviting participants to be measured, as well in participants who declined to be measured. However, no demographic differences were identified between those with and without measurements taken. Further research is needed to confirm findings in a larger sample and to see whether a convenience music festival audience differs from the general young adult population in terms of self-reported weight and height accuracy.In conclusion, our results suggest that the majority of young people participating in a risk behavioural survey are able and willing to self-report their height and weight. The classification of overweight/obesity based on derived self-report BMI has high sensitivity against independent measurement in this setting. Given the wide reach and efficiency of surveys including self-reported measures, these results suggest that that self-reported height and weight are a suitable proxy to estimate the prevalence of overweight and obesity by BMI in a community-based sample of young people, but some underestimation of overweight/obesity is likely and should be taken into consideration.The authors declare that they have no competing interests.The following co-authors have contributed to the work: AB in data collection, data analysis, manuscript preparation and manuscript review; AP in study design, manuscript preparation and manuscript review; MG in data analysis and manuscript review; RFP in manuscript preparation and manuscript review; MSCL in study design and manuscript review; MH in study design, manuscript preparation and manuscript review. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2288/12/175/prepub


Examine whether false-positive HIV enzyme immunoassay (EIA) test results occur more frequently among pregnant women than among women who are not pregnant and men (others).To obtain a large number of pregnant women and others tested for HIV, we identified specimens tested at a national laboratory using Genetic Systems HIV-1/HIV-2 Plus O EIA from July 2007 to June 2008.Specimens with EIA repeatedly reactive and Western blot-negative or indeterminate results were considered EIA false-positive. We compared the false-positive rate among uninfected pregnant women and others, adjusting for HIV prevalence. Among all reactive EIAs, we evaluated the proportion of false-positives, positive predictive value (PPV), and Western blot bands among indeterminates, by pregnancy status.HIV prevalence was 0.06% among 921,438 pregnant women and 1.34% among 1,103,961 others. The false-positive rate was lower for pregnant women than others . Pregnant women with reactive EIAs were more likely than others (p<0.01) to have Western blot-negative (52.9% vs. 9.8%) and indeterminate results (17.0% vs. 3.7%) and lower PPV (30% vs. 87%). The p24 band was detected more often among pregnant women (p<0.01).False-positive HIV EIA results were rare and occurred less frequently among pregnant women than others. Pregnant women with reactive EIAs were more likely to have negative and indeterminate Western blot results due to lower HIV prevalence and higher p24 reactivity, respectively. Indeterminate results may complicate clinical management during pregnancy. Alternative methods are needed to rule out infection in persons with reactive EIAs from low prevalence populations. Universal screening to identify HIV infection in pregnant women is recommended so that infected women can be linked to care, start prophylaxis, plan for delivery, and avoid transmission through breastfeeding Although a previous study indicated that parity is associated with false-positive HIV test results We retrospectively collected testing data without personal identifiers from serum and plasma specimens from persons 12 years of age and older that had been tested using the peptide-based Genetic Systems HIV-1/HIV-2 Plus O EIA  at laboratories operated by a national laboratory from July 1, 2007, through June 30, 2008. Specimens with repeatedly reactive EIA results had been tested using the Genetic Systems HIV-1 Western blot kit . EIA and Western blot tests were conducted according to manufacturer instructions. Specimens were categorized by pregnancy status based on whether they were obtained from persons who were pregnant, not pregnant, or persons for whom pregnancy status was unknown. A specimen was considered to be from a woman who was pregnant on the day the blood was collected for GS EIA testing if at least one of the following criteria was met: i) positive urine or serum human chorionic gonadotropin (HCG)-based pregnancy test, ii) a simultaneous request for either a cytogenetic test, a maternal serum screen panel, rubella serology as part of an obstetric panel, a one-hour glucose tolerance test for gestational diabetes, or iii) provision of an ICD-9 code for normal pregnancy or high-risk pregnancy or other pregnancy-related ICD-9 code. A specimen was categorized as being from a person who was non-pregnant when it was from: i) a male, ii) a female with a negative pregnancy test or ICD-9 code for a negative pregnancy test; iii) a woman age 55 or over, or iv) a female with an unspecified age who did not meet the above described pregnancy criteria. Specimens were categorized as being from a person whose pregnancy status was unknown when either: i) a female did not meet any of the pregnant or non-pregnant criteria listed above, ii) the submitted test requisition specified the individual as a male, but they simultaneously met one of the pregnancy-related criteria, or iii) gender was not specified. Criteria for these categories were based on discussions with staff from the American College of Obstetrics and Gynecologists coding department. Further, in a prospective study conducted at the same laboratories, all specimens from persons categorized as pregnant using these criteria (n = 474) were found to be pregnant on a quantitative HCG pregnancy test and 1430/1431 (99.93%) labeled as not pregnant using these criteria were found not to be pregnant using a quantitative HCG pregnancy test.The number and percent of specimens with HIV test results in each of the following HIV infection categories were quantified. Specimens with HIV-negative EIA results were considered uninfected. Specimens with a repeatedly reactive EIA and positive Western blot were considered HIV-infected. A false-positive HIV test result was defined as a repeatedly reactive EIA followed by a negative or indeterminate Western blot result. The false-positive rate was defined as [# false-positive/# uninfected persons] where uninfected persons were considered those who were EIA-negative and those with false-positive results. The false-positive rate is equivalent to [1-specificity]. The false-positive rate was compared for: i) pregnant women versus persons who were non-pregnant, ii) for pregnant women versus women of reproductive age (12 to 55 years) who were non-pregnant, and iii) for pregnant women versus persons whose pregnancy status was unknown. We also examined the false-positive rate by the following co-factors: age, month of testing, and laboratory facility. Race/ethnicity data were not available. We analyzed the risk of false-positive HIV test result for pregnant women compared to persons who were not pregnant using a Mantel Haenszel odds ratio (OR) which was adjusted for HIV prevalence at each laboratory facility. The Centers for Disease Control and Prevention (CDC) received de-identified study data in aggregate, so multivariable regression techniques to adjust for co-factors beyond HIV prevalence at laboratories, which were related to pregnancy and false-positive HIV EIA test results, could not be performed.Among all specimens with repeatedly reactive EIAs, we evaluated the proportion of specimens that were Western blot-negative, indeterminate, or positive, and the positive predictive value of the EIA test, by pregnancy status. Among those with Western blot-indeterminate results, we evaluated whether antibody reactivity to specific HIV polypeptide bands was detected more frequently among pregnant women than others. Statistical comparisons were made using the chi-square test to assess the difference between two proportions. The statistical software package SAS v9.1  was used for data analysis.Since the laboratory dataset was based on distinct patient encounters, individuals may have been included in the analysis dataset more than once . It is unlikely that persons with EIA negative results had more than one test result during the analysis period, with the possible exception of pregnant women from areas of high HIV prevalence Probabilistic sensitivity analyses with 10,000 repetitions were conducted to evaluate the false-positive rate among pregnant women assuming that the proportion of specimens from persons of unknown pregnancy status to be categorized as pregnant was binomially distributed This study was determined to be research not involving identifiable human subjects by the National Center for HIV, Viral Hepatitis, STD, and TB Prevention at the Centers for Disease Control and Prevention. According to HIPPA regulations, protected health information can be disclosed, without the written authorization of the individual, to a public health entity for public health activities and purposes, such as this investigation. For this project, a laboratory shared health information (test results), without personal identifiers, with CDC.During the analysis period, 3,357,200 specimens had an EIA test result. Of those, 921,501 (27.5%) were from pregnant women, 1,104,118 (32.9%) were from persons who were non-pregnant, and 1,331,581 (39.7%) were from persons whose pregnancy status was unknown . The criOf 3,356,764 (99.9%) specimens with interpretable HIV test results, 541 (0.06%) of 921,438 from pregnant women and 14,788 (1.34%) of 1,103,961 from persons who were non-pregnant were Western blot-positive . The falThe false-positive rate was lower in those study subjects who were the median age of 30.2 years or younger [0.17% ] compared with those who were older than 30.2 . The median monthly HIV EIA false-positive rate for this one-year study period was 0.17%, and ranged from 0.16% to 0.21%. The occurrence of false-positives did not appear to be seasonal (not shown). The median false-positive rate by individual laboratory facility was 0.14% (range 0.04% to 0.65%). The two laboratory facilities with the highest HIV EIA false-positive rates function primarily as reference laboratories for hospitals and other facilities, and are more likely to receive specimens that initially screened HIV-repeatedly reactive than those tested at other regional facilities within the same laboratory system. The HIV prevalence at the laboratory facilities ranged from 0.17% to 2.8%, and the two reference laboratories mentioned previously had the highest prevalence rates. After adjusting for prevalence at each laboratory facility, pregnant women were less likely to have false-positive screening test results than non-pregnant persons  .Among all specimens with repeatedly reactive HIV EIA results, those from pregnant women were more likely to test Western blot-negative and indeterminate than those from persons who were not pregnant  and , respectively . Among pOf 4,329 specimens with repeatedly reactive EIA and Western blot-negative results, 346 (8.0%) had at least one follow-up testing event by July 2008: 106/951 (11.2%) pregnant females, 119/1675 (7.1%) non-pregnant persons, and 121/1703 (7.1%) persons with unknown pregnancy status. Of those with follow-up test results within a month following the initial EIA-reactive and Western blot-negative result, fewer pregnant women than non-pregnant persons had a Western blot-positive result . Nine non-pregnant persons and no pregnant women had follow-up results between 31 days and one year that were Western blot-positive.Of 1,640 specimens with repeatedly-reactive HIV EIA and Western blot-indeterminate results, 187 (11.4%) had at least one follow-up testing event by July 2008: 70/306 (22.9%) pregnant women, 57/633 (9.0%) non-pregnant, and 60/701 (8.6%) unknown pregnancy status. Slightly more than half (57.2%) of the persons with follow-up test results within a month after the initial indeterminate Western blot result had follow-up testing. Fewer pregnant women than non-pregnant persons had a positive Western blot result within one month of their indeterminate result . Two pregnant women and seven non-pregnant persons with initial results that were indeterminate had follow-up results between 31 days and one year that were Western blot-positive.Following the sensitivity analysis in which specimens were re-categorized as pregnant from the pregnancy-unknown category, the false-positive rate among pregnant persons was 0.15%. After specimens were categorized as non-pregnant from the pregnancy-unknown category and approximately 18% (21/119) of repeatedly reactive EIA and Western blot-negative and 35% (20/57) of indeterminate specimens were reclassified because they may have represented true infections, the false-positive rate among non-pregnant persons was 0.16%. If the proportion misclassified as false-positive were twice the rate observed among those designated as false-positive with follow-up testing, the false-positive rate among non-pregnant persons would be higher than 0.15%, the false-positive EIA rate among pregnant women based on this sensitivity analysis.We examined over three million HIV EIA test results and found that false-positive results were rare (less than two in a thousand) and occurred at a rate similar to that described in the manufacturer's package insert . Further, they occurred less frequently among persons who were pregnant (0.14%) than among persons who were not pregnant (0.21%). It is possible that the false-positive rate was higher in non-pregnant persons because some were actually infected, and in the process of seroconversion, particularly non-pregnant persons with indeterminate results showing viral bands who reside in areas of high prevalence and have other risk factors for HIV. Ideally, truly HIV-infected persons would have positive confirmatory results instead of indeterminate Western blot results, but new EIAs can detect infections earlier than the Western blot develops the bands needed to be considered positive In this study and others, repeatedly reactive HIV EIA results were unlikely to be indicative of HIV infection in pregnant women Pregnant women with reactive HIV EIA results would benefit from a testing algorithm which would accurately rule-out HIV infection status in a timely way before the onset of labor, without the provision of indeterminate results which may cause undue stress in someone who is not infected. It is not yet known whether an algorithm using two antibody EIAs with different antigen or binding properties in series could be used in pregnant women with a reactive screening result or whether both EIAs would have concurrent non-specific reactivity in uninfected persons This study was subject to several limitations. Study participants could have been included in the study more than one time, but it is unlikely that de-duplicating would impact the findings, as few subjects repeated testing even when this testing was recommended. Persons with negative EIA results are unlikely to have had follow-up testing, and slight changes to the large number of non-reactive tests would have little impact on false-positive rates. Pregnant women with false-positive HIV EIA screening results were more likely to have recommended repeat testing, so if these follow-up specimens were de-duplicated, the number of false-positives among pregnant women would decrease and the rate would still be lower than that among non-pregnant persons. The rate of false-positive EIAs in pregnant women and others may vary by the EIA and supplemental test used, although since the prevalence of HIV in pregnant women in the US tends to be low, the predictive value of a positive EIA screening test result is likely to remain low regardless of the screening test used. There is a possibility of misclassification of pregnancy status because few persons classified as pregnant had concomitant pregnancy tests, however, most persons were categorized as pregnant based on an ICD-9 code for pregnancy, so misclassification is unlikely to be extensive, and HCG tests conducted on prospectively collected specimens indicate that this misclassification was likely very limited. Precise estimates of the proportion of pregnant women and others with repeatedly reactive EIA results and negative or indeterminate Western blot results which are truly infected based on nucleic acid testing or other follow-up testing are not available. The precision of the sensitivity analyses reported here could be improved with better estimates of the rate of such misclassification. Ideally, additional variables such as age and race could have been included in a multivariable model examining false-positive results by pregnancy status. The false positive rate was statistically lower in persons younger than the median age, but the difference was 2 in 10,000, which may not be meaningfully different, so it may not be a strong confounder. Finally, 359 women with an unspecified age should have been included in the pregnancy unknown category instead of the not pregnant category, but they could not be re-categorized because we did not receive line level data. However, they constituted approximately 0.03% of the not pregnant group, so the impact of re-categorizing their pregnancy status on study findings would be negligible.Approximately 70% of pregnant women in the United States receive prenatal antibody screening for HIV infection, and increasing this proportion is necessary given that approximately one quarter of new HIV infections occur among women, many of whom are of child-bearing age


Ground-based studies on space radiation indicate that exposure to charged particle radiation at relatively low doses may impair neuronal functions. Decrements in excitatory synaptic transmission and plasticity in the hippocampus have been previously reported in mouse brains irradiated with iron nuclei, but relatively little is known about the effects of protons on the synaptic activity in the hippocampus. Behavioral and neurophysiological decrements in irradiated subjects are also commonly observed in Alzheimer's disease (AD), and we hypothesized that irradiation with protons may exacerbate AD-like neurodegenerative pathology. We used transgenic (TG) mice with AD-like neurodegeneration to test whether whole-body irradiation with protons  accelerates the onset of AD and/or exacerbates synaptic impairments. We measured evoked excitatory synaptic potentials, synaptic plasticity and spontaneous oscillations in hippocampal slices prepared from APP/PSEN1 double TG mice  at 6 and 9 months post-irradiation.Our electrophysiological recordings indicate that most of the radiation-induced synaptic decrements can be observed at 9 months rather than 6 months post-irradiation and they are differently expressed in TG and wild-type (WT) mice. Presynaptic excitability evaluated by the amplitude of fiber volleys was significantly increased in non-irradiated TG mice when compared with non-irradiated WT mice, and irradiation did not cause further alterations. The post-synaptic, dendritic excitability, evaluated by the initial slope of the excitatory post-synaptic potentials (EPSPs), was reduced in TG mice exposed to 0.5 Gy, but increased relative to WT mice at the same dose. Interestingly, the suppressive effect on EPSP in TG mice was not observed at 1 Gy. Post-synaptic firing of action potentials, evaluated by the amplitude of population spikes (PS), was increased in non-irradiated TG mice when compared with WT controls. However, these increases were significantly reduced by irradiation at 0.1 and 1 Gy. Long-term potentiation of the EPSPs, a widely used electrophysiological correlate of memory formation, was not significantly affected by irradiation. Last, in WT mice, we observed a significant radiation-induced decrease in the frequency of epileptiform oscillations in the CA3–CA1 network triggered by reduced concentration of extracellular magnesium. These spontaneous waveforms (SW) are reminiscent of ‘sharp-wave/ripple complexes’ that have been associated with memory consolidation in the hippocampus. Interestingly, in the behavioral part of our project, irradiation impaired hippocampal learning in WT mice, while it did not affect performance in TG mice [


In a screening study for silent atrial fibrillation (AF), which is a frequent source of cardiac emboli with ischemic stroke, the proportion of non-participants was considerable and their clinical profile differed from the participants’ profile. We intended to geo-map the target population and non-participation in an attempt to understand factors related to screening uptake and, thereby, obtain useful information needed to intervene for improved uptake.In the municipality of Halmstad, Sweden, all residents born in 1934–1935 were invited to the screening study during April 2010 to February 2012. The total study group included 848 participants and 367 non-participants from 12 parishes. Geo-maps displaying participation, along with target-population-based geo-maps displaying proportion of immigrants and ischemic stroke incidence, were used.Smoothed non-participation ratios (SmNPR) varied from 0.81 to 1.24 across different parishes . Among high risk individuals, the geographical variation was more pronounced (SmNPR range 0.75–1.51). Two parishes with higher share of immigrants and elevated population-based ischemic stroke incidence showed markedly lower participation, particularly among high-risk individuals.AF screening uptake varied evidently between parishes, particularly among high-risk individuals. Geo-mapping of target population and non-participation yielded useful information needed to intervene for improved screening uptake. Atrial fibrillation (AF) is the most frequently encountered clinical arrhythmia. Outcome is affected among patients with AF with a higher mortality, higher risk of stroke, and higher risk for hospitalizations -3. At leAF can sometimes be present without symptoms, often referred to as silent AF. When silent AF is paroxysmal, diagnosis might be difficult. The actual frequency of silent AF in the population is not yet known. Silent AF is connected to an increased risk of stroke . FurtherOral anticoagulation (OAC) therapy is the recommended treatment for stroke prophylaxis in patients with AF and thromboembolic risk factors.Hence, screening for silent AF seems suitable in risk populations. We (JE and MR) have initiated such a screening program aiming at stroke prevention. Results from our initial screening study have been reported elsewhere . In our A few determinants of non-participation have reported from a two other AF screening studies. In a study in the UK including individuals over 65 years of age, problem getting to the clinic was the most frequent stated reason for not attending . ClearlyOur objective was to geo-map the target population and non-participation in an attempt to understand factors related to screening uptake and, thereby, obtain useful information needed to intervene for improved uptake. In the present report we apply a novel approach, using geo-maps, to analyze participation in a community-wide screening program for AF and its geographical (neighborhood area) relation to cardiovascular risk and immigrant group status.st 2010. Figure st 2012, the municipality had 14.6% immigrants and the five largest immigrant groups were from former Yugoslavia, Bosnia & Hercegovina, Iraq, Poland and Finland.The municipality of Halmstad is located in the southwest of Sweden and consists of 12 parishes. The total population was 91,800 inhabitants by January 1Statistics Sweden provided parish-level data on the proportion of immigrants among all residents aged 75–79 years. The Swedish population registry contains information on birth country, as well as residence area in Sweden, for each citizen.Population-based data on ischemic stroke incidence were obtained for the residents aged 70+ years in the calendar period 2006–2010. For each calendar year, we stratified the population by sex and age group . The ischemic stroke cases in each stratum were obtained from the regional in-patient registry . The resulting parish-specific standardized incidence ratios (SIRs)  reasonably reflect the predicted SIRs for the target population, provided unchanged impact of underlying risk factors. In other words, assuming that the target population will be followed prospectively, the SIRs provide reasonable information regarding the expected ischemic stroke risk variation in the study area. Data on stroke incidence derive from Swedish inpatient statistics, provided by The National Board of Health and Welfare. Stroke diagnosis is derived from discharge reports without conditions regarding level of care or investigations undertaken.The screening study was approved by the regional health research ethics board at Lund University, Sweden, and conducted according to the declaration of Helsinki.All residents in Halmstad municipality born in 1934 and 1935 were invited to the AF screening program, which was performed during April 2010 to February 2012. The study invitation was sent by mail; if there was no response within 4–6 weeks, a reminder was sent. Screening visits were undertaken at a single centre at the hospital. The total study group included 848 participants (484 women) and 367 non-participants (213 women) from the 12 parishes . We had to disregard 75 persons who actively declined study inclusion since we could not geo-code those persons, nor collect clinical data on ethical grounds. Hence, the present definition of “non-participation” refers to those who did not respond to the invitation. The absolute overall non-participation reported elsewhere  was ther2  risk classification [At the index visit, all participants were asked to report their medical history including presence of AF, antithrombotic treatment and thromboembolic risk factors according to the CHADSfication . If a pa2-score of at least 2 and with no known AF after index visit were offered extended ECG recording with a hand-held event recorder  and instructed to record 20 or 30 seconds of ECG twice daily for two weeks. Further details on the screening study are reported elsewhere [2. Both hospital and primary care records and prescriptions were studied. Non-participants were informed via letter and advertisement about this data collection and were thereby offered the possibility to withdraw their participation in this part of the study.A 12-lead ECG was recorded at index visit. We hypothesized that the diagnostic yield would be higher among patients with at least one of these risk factors, hence participants with a CHADSlsewhere . Medical2) were available for the 848 participants and 354 non-participants. We also analyzed data restricted to high risk individuals, defined as having CHADS2 ≥ 2.Individual data on stroke risk factor scores (CHADSEach inhabitant was geo-coded with respect to his/her neighborhood area (parish). Geo-maps of were produced by using ESRI® ArcGIS system . The geo-map on ischemic stroke incidence was produced by computing the smoothed standardized incidence ratios (SIRs) for each parish, using the free software Rapid Inquiry Facility, which provides an extension to ESRI® ArcGIS functions ,19. The lower participation than expected based on the data from total study group. Moreover, for each parish, a smoothed NPR (SmNPR) were obtained by running the empirical Bayesian mapping model, using a prior Gamma-model for the parish-specific non-respondent rate ratios [i/Ei) to estimate the parish-specific non-participation ratios (NPRi for parish i). We applied the conventional statistical Poissonmodel for the observed numbers: Oi ~ Poisson(NPRi×Ei). The empirical Bayes smoothing of the NPRi:s across the parishes was performed using a prior Gamma-model: NPRi ~ Gamma. Such Bayesian smoothing yielded “shrinkage” of the conventional observed-to-expected ratios (NPRs) towards the expected average NPR = 1. We underline that, for a parish with few study persons, more pronounced shrinkage of an elevated/lowered NPR was obtained, as compared with a parish with a large number of study persons. Hence, by presenting smoothed geo-maps of participation, rational adjustments of the parish-specific NPRs are taken into account [A parish-level non-participation ratio (NPR) was calculated as the observed-to-expected ratio, where the expected number of non-participants was obtained from the sex-specific non-participation rates for the total study group. Hence, NPR > 1 indicates e ratios ,20. More account -21: the 2 scores between the participants and non-participants were compared by the Mann–Whitney test.The proportions of high risk individuals and stroke risk factors among the participants and non-participants, respectively, were compared by Fisher’s exact test. Moreover, for the high risk individuals, the CHADSThe proportion of immigrants among the residents aged 75–79 years varied notably across the parishes . Consequently, the corresponding SmNPRs became more pronounced when considering participation among the high risk individuals  considered, however, the fully Bayesian approach in Rapid Inquiry Facility along with free software for Bayesian data analysis, WinBugs  yielded Regarding individual-level data for the non-participants, there was limited access to socio-demographic characteristics due to ethical restrictions. In fact, the individuals of the study population could only be stratified on stroke risk factors (we used the CHADS2-score) and sex, in order the perform Bayesian smoothing of non-participation rates across the parishes. Provided richer data, geographically-weighted regression offers an interesting alternative method to identify spatial discrepancies in observed-to-expected ratios .Data on thromboembolic risk factors among non-participants were collected from medical records which has certain limitations.2 ≥ 2.Our data were too spare for analyzing participation among high risk individuals defined by a more strict definition than CHADSIn conclusion, participation in an initial AF screening program varied notably between parishes, in particular among high risk individuals. Low participation was linked to higher stroke incidence and higher proportion of immigrants in the target population. Geo-maps on different aspects of participation provided useful information needed to intervene for improved screening uptake.Dr Engdahl has received lecture fees from AstraZeneca, Medtronic and Boehringer Ingelheim and consultant fees from Sanofi Aventis. Dr Rosenqvist has received lecture fees from Sanofi Aventis, Merck Sharpe & Dome, Bayer, Boehringer Ingelheim, Pfizer and Medtronic, consultant fees from Sanofi Aventis, Merck Sharpe & Dome, Nycomed, Bristol Meyers Squibb, Bayer, Medtronic and research grants from Sanofi Aventis, Merck Sharpe & Dome boehringer Ingelheim.JE conducted the screening study, extracted data from the screening study dataset and drafted the manuscript. AH retrieved data from population and stroke registries and made statistical analyses. MR conducted the screening study and participated in study design. US contributed to study design, made statistical analysis including data for geo-maps and drafted the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2458/13/715/prepub