Anopheles populations capable of withstanding lethal doses of insecticides has weakened the efficacy of most insecticide based strategies of vector control and, has highlighted the need for further studies on the mechanisms of insecticide resistance and the various factors selecting resistant populations of mosquitoes. This research targeted the analysis of breeding sites and the oviposition behaviour of susceptible and resistant populations of Anopheles in localities of spilled petroleum products. The aim was to establish the possible contribution of oil spillage in the selection of pyrethroid resistance in malaria vectors.The emergence of Anopheles breeding sites were identified and the insecticide susceptibility of the Anopheles gambiae populations mapped in 15 localities of South Western Nigeria. The presence of oil particles as well as the turbidity, the dissolved oxygen and the pH of each identified breeding site was recorded. Data were cross-analysed to correlate the habitat types and the insecticide susceptibility status of emerging mosquitoes. The second phase of this study was basically a laboratory model to provide more information on the implication of the spillage of petroleum on the selection of pyrethroid resistance in An. gambiae.An. gambiae samples collected in the South Western Nigeria. Data from this study established a link between the constituency of the breeding sites and the resistance status of the emerging Anopheles.Moderate levels of resistance following exposure to permethrin-impregnated papers were recorded with the majority of An. gambiae in south-western Nigeria. Compiled results from field and laboratory research point out clear relationships between oil spillage and pyrethroid resistance in malaria vectors. The identification of this factor of resistance could serve as strong information in the management of insecticide resistance in some West African settings.This study has revealed the segregational occupation of breeding habitats by pyrethroid resistant and susceptible strains of  Anopheles gambiae, Anopheles arabiensis and Anopheles funestus. These species co-exist geographically across sub-Saharan Africa and can inhabit the same villages, shelter in the same houses, and feed on the same individuals [Malaria morbidity and mortality in tropical Africa remains high compared to other malaria-endemic areas of the world . This isividuals . Vector Anopheles resistant to insecticides used in public health has been recorded [An. gambiae s.l. [An. funestus s.l. [An. gambiae to pyrethroids is documented in several parts of Africa [et al [An. gambiae in particular, lay their eggs in breeding sites located around agricultural settings. These eggs undergo a selection pressure from agricultural pesticides, which leads to the emergence of resistant strains [Anopheles species [An. gambiae in south-western Nigeria. In the laboratory, the oviposition behaviours and the larval growth of resistant and susceptible populations of An. gambiae from the field were monitored in reconstituted oily and non oily breeding sites. The identification of this factor of resistance could serve as strong indicator to help in the management of insecticide resistance in some West African settings.In the last decade in many African countries, the emergence of populations of recorded ,4. This iae s.l.  and An. tus s.l. . The resf Africa -9 and haf Africa  and factf Africa . Accordia [et al , many mo strains . This ev species , has guiAnopheles larvae were recognized by their morphology and their horizontal position on water surface [This study was conducted in the south-western region of Nigeria. Samples were collected from five states in the region namely Ogun, Oyo, Osun, Ondo and Ekiti states Figure . Standin surface . Larvae  surface . A Globain situ using the multi-meter . Macroscopical parameters considered in this study include the presence of petroleum particles in the water, the thickness of the water and the presence of oil layer at the surface of the breeding sites.Water samples collected from each identified breeding site were macroscopically described, and their pH and dissolved oxygen analyzed Anopheles emerging from the identified breeding sites, were bio-assayed using discriminating doses of insecticides. Bio-assays were carried out following WHO protocols [An. gambiae were exposed for one hour to papers impregnated with diagnostic dosages of permethrin (0.75%). For each test, five test tubes were used: one for the control and four for exposed mosquitoes. Control tubes contained filter papers impregnated with silicon oil (insecticide carrier), whereas treated papers were impregnated with diagnostic doses of insecticide plus carrier. An average of twenty mosquitoes was introduced in each tube. After one hour, mosquitoes were transferred to holding containers and provided with cotton pads with 10% sucrose solution. Mortalities were recorded at 24 hours and the susceptibility status of the population was graded according to the WHO protocol [Two to five-day old rotocols . Femalesprotocol .Anopheles from WHO Bio-assays were analysed at molecular level. PCR-species [Anopheles to identify the various members of An. gambiae complex encountered in each site. The next set of PCR focused on molecular forms [An. gambiae sensu stricto (s.s.) from the previous screening. The PCR forms sub-grouped the An. gambiae s.s. into two molecular forms: An. gambiae s.s. (M) and An. gambiae s.s. (S). The last series of PCRs was to assess the presence of the kdr mutations in An. gambiae ss. populations [In each locality, 20–30 females -species  was condar forms  and invoulations An. gambiae Ojoo was selected in the locality of Ojoo in Ibadan, Oyo state. This strain is resistant to pyrethroids . These samples (crude samples from the field) were used in the laboratory for the simulation of breeding sites. "un-sieved or crude or oily sites" indicated in this study was directly reconstituted by putting two litres of the water from the field into laboratory containers.An. gambiae ready to lay eggs were introduced into a cage provided with 2 types of breeding sites for their oviposition: a breeding site with petroleum products from the field and a breeding site with no trace of petroleum products (control)  Figure . This exAnopheles in the breeding site with petroleum products was counted and compared with that in the breeding site with no petroleum products. Statistical comparisons conducted on data generated during this experiment led to determination of the oviposition preference of each species and to comment on the level of selection pressure exercised by oily breeding sites during oviposition.The number of eggs laid by each strain of An. gambiae were introduced into breeding sites containing two liters of water collected in areas of spilled petroleum products in the south-western Nigeria. This experiment was replicated four times. The hatching rate and the number of larvae getting to pupae stage was determined for each strain of Anopheles (Ojoo and UI). Control breeding sites using clean water from the field with no trace of petroleum products were also seeded with eggs of the same species and monitored in tandem with test breeding sites. The number of hatched eggs and the number of larvae progressing to the pupae stage in each type of breeding sites and for each strain of Anopheles were determined. Statistical comparisons were used to determine the impact of oil spillage in the development of larvae of Anopheles Ojoo and UI and to identify the level of selection pressure exercised by oily breeding sites during larval development.Two hundred eggs of Anopheles, their physico-chemical properties, the resistance status of each tested population of Anopheles. The cross-analysis of these parameters led to identifying the impact of the quality of breeding sites on the emergence of resistant populations of Anopheles. Statistical tests of comparison were used to highlight the oviposition preference and the level of selection pressure exercised by oily breeding sites during larval development.Analysis using computer software  were performed on sets of data gathered from surveyed localities. Parameters for analysis include: the full description of the breeding sites of An. gambiae to permethrin impregnated papers, a good spread of resistance was recorded in all the five states surveyed. Out of the 15 tested populations of An. gambiae s.l., 12 populations were clearly resistant to permethrin, whereas three were within the range of susceptibility as defined by WHO standards [Following the exposure of females tandards .Anopheles spp. from UI . In Osun state, susceptibility was recorded at Modakeke  and resistance at Lagere  localities.In Oyo state, out of the five localities studied , resistance was clearly recorded at Basorun , Ojoo , Challenge  and Oja-tuntun . No case of resistance was recorded among Anopheles populations from the two localities surveyed: Ilesha garage (Akure) and Owena (Owena) were all resistant to permethrin .In Ondo state, the Anopheles from the two localities sampled; 85% mortality rate was recorded at Ati-kankan1 (Ado-ekiti) and 88% at Ati-kankan2 (Ado-ekiti).In Ekiti state, resistance was recorded with In Ogun state, resistance was recorded at Ogere1  and Ogere2 , situated on the Lagos-Ibadan express way and at Mobalufon  in Ijebu-ode. A susceptibility pattern was noticed at Imowo , locality of Ijebu-ode.In most screened breeding sites, cadavers of larvae were recorded: probably due to lethal activities of petroleum products. The summary of the results of bio-assays is shown in Table .Using geographical information recorded with the GPS, localities screened were projected on a map of Nigeria and areas of permethrin resistance demarcated. The map generated from this study showed a spread of resistance in most states of South Western Nigeria. The levels of resistance registered in the localities of Basorun, Owena, and Ogere were relatively consistent compare to other sites. On the other hand, no resistance was found in UI. A reduced susceptibility to permethrin was recorded in Modakeke and Imowo Figure .An. gambiae. Very slight differences were obtained between the pH of breeding sites producing resistant populations of An. gambiae and those producing susceptible populations. Contrary to data on the pH, breeding sites having petroleum particles and therefore low levels of oxygen seemed to produce resistant strains of mosquito. It is possible that the survival rate of eggs laid by susceptible mosquitoes in oily breeding sites is low. This inhibition of eggs or larvae development (P = 0.0015) could explain the low presence of susceptible populations of Anopheles in oily breeding sites. In the three breeding sites with little or no oil particles , a consistent number of pyrethroid susceptible populations of An. gambiae was recorded  and the pyrethroid susceptibility status of emerging adults of ed Table  and 3.Anopheles exhibited a high reluctance for laying eggs in breeding sites containing petroleum products. Out of a mean number of 1,900 eggs laid in each cage by the susceptible strain Anopheles UI, 4.5% (86 eggs) of these eggs were deposited in oily breeding sites and 95.5% (1814 eggs) in the clean breeding site (control site). With the resistant strain Anopheles Ojoo, Out of a mean number of 2,425 eggs laid in cages, 77% (1875 eggs) of these eggs were deposited in breeding sites with clean water (control site) whereas 23% (550 eggs) of these eggs were laid in breeding site with petroleum debris . The very low tolerance to oily breeding sites by pyrethroid susceptible populations of Anopheles during oviposition translates the high selection pressure exercised on this mosquito species in localities where most breeding sites are covered with petroleum products.In the laboratory, both pyrethroid susceptible and resistant strains of Anopheles UI monitored during this experiment, 200 eggs were introduced in breeding sites containing oil particles (test) and the remaining 200 in the breeding site with no oil (control). Results generated showed that 61% (122 eggs) of the 200 eggs hatched in oily breeding sites and 87% (174 eggs) of 200 eggs hatched in breeding site with no petroleum products (control). With the Ojoo strain, 84% (168 out of 200 eggs) hatching rate was recorded in the control breeding site whereas 63% (126 out of 200 eggs) hatching rate was found in the breeding site with oil products. These results point to a significant impact of oil products on the hatching of eggs of both tested strains but with a more pronounced hatching inhibition on the susceptible strain Anopheles UI   could reach the pupae stage in breeding sites polluted with petroleum products (only 1 pupa from the 122 L1-larvae emerging from hatched eggs). With Anopheles Ojoo 27%  of larvae were able to reach the pupae stage when reared in water with oily debris. When the rearing was conducted in clean breeding sites (control breeding sites), we recorded a relatively high number of pupae from both strains (64% and 66% of L1-larvae emerging from hatched eggs got to the pupae stage in non oily breeding sites with the susceptible and resistant strain respectively)  Figure . Althougs Figure .An. gambiae populations when they are challenged with petroleum products. The main goal of this study was to identify the relationship between oil spillage and the emergence of pyrethroid resistance in malaria vectors in the South Western Nigeria. Results from insecticide bio-assays revealed a spread of pyrethroid resistance in the South Western Nigeria. The presence of Anopheles populations capable of withstanding diagnostic doses of permethrin was initially reported in this part of Nigeria [This study investigated the possible changes into  Nigeria ,20.Anopheles populations [An. gambiae lay their eggs in breeding sites containing insecticide residues. Larvae from these eggs are subjected to a selection pressure leading to the pyrethroid resistance [Anopheles breeding sites probably exercise a severe selection pressure by killing most susceptible strains of An. gambiae and allowing the emergence of mainly resistant individuals as observed in the laboratory. Projected in the field, it is possible that this laboratory model could explain the absence of susceptible strains of An. gambiae in oily breeding sites and the predominance of resistant populations of Anopheles in areas where most breeding sites are covered by spilled petroleum products (Figure kdr mutations on samples analysed during this study suggests the selection of mechanisms different from kdr mutations by petroleum products. The use of petroleum products against malaria vectors has been reported in several communities in the Western part of Africa [The massive use of pesticides in agricultural settings has been well documented as a factor contributing to the emergence of resistance in ulations . As reposistance . It is ps Figure  and 7. Ts Figure . The absf Africa . SimilarAnopheles may lay their eggs in these oily breeding sites and selection pressures may be exercised during series of larval development cycles. A cross-resistance seems to exist between the capability to survive petroleum exposures and lethal doses of pyrethroids.Nigeria is among the first oil producers in the world . Oil dumAn. gambiae from the South Western Nigeria using the "detox chip" are in progress at the Liverpool School of Tropical Medicine, UK. This may elucidate the gene expression profile of species of Anopheles selected with petroleum products and further contribute to highlighting the implication of petroleum products in the emergence of pyrethroid resistance in South Western Nigeria.The molecular mechanism developed by populations of Anopheles against spilled petroleum products is unclear. Further investigations using advanced molecular techniques and technologies to investigate the molecular pathways involved in the emergence of pyrethroid resistance from series of exposures to petroleum products are needed. Microarray analyses of samples of An. gambiae and, has highlighted the potential contribution of spilled petroleum products in the development and spread of pyrethroid resistance in malaria vector in south-western Nigeria. Similar to the implication of agricultural pesticides in the emergence of pyrethroid resistance in mosquito populations, spilled petroleum products are washed by rains and accumulate in low-lying areas where, mixed with water, they constitute breeding spots for mosquitoes. Anopheles will lay their eggs in these oily breeding sites; both the eggs and the larvae emerging from hatched eggs will undergo series of selection pressure which ends with the emergence from these oily breeding spots of adult populations of An. gambiae capable of withstanding lethal doses of pyrethroids. This massive elimination of susceptible populations of mosquitoes by spilled petroleum products implicates oil spillage in the selection of pyrethroid resistant populations of Anopheles in the south-western Nigeria.This study analysed the potential impact of oily breeding sites in the development of both susceptible and resistant strains of RFD conceived the study and participated in the implementation, data interpretation and manuscript preparation. HSB, ONC contributed in the study design and were fully involved in the implementation of this research and the write up of the manuscript. JMCD contributed in the study design and data analysis. HK, HB, PKOK and MT participated in the design of the study and substantially helped in drafting the manuscript. MCA and AAB guided the study from conception to the manuscript finalization. All authors read and approved the final manuscript.


New Zealand Black (NZB) mice are a well-known animal model of human autoimmune disease. Although the mechanism for development of autoimmunity is unclear, NZB mice are well known for severe thymic microarchitecture abnormalities. It is thought that thymic dendritic cells (DC) may play a role in thymic education and contribute to the autoimmune process. To address this issue and, in particular, that qualitative and/or quantitative differences exist in thymic DC, we took advantage of a novel restriction analysis system that allow definition of differences in the expression of tyrosine kinases using highly enriched populations of thymic DC from NZB compared to BALB/c and C57BL/6 mice. The method chosen, restriction analysis of gene expression, allowed the determination of protein tyrosine kinase transcription profiles. We report herein that NZB mice have a significant upregulation of C-met compared to the control strains. The abnormality of the C-met transcription was confined to thymic DC. We believe that its abnormal expression reflects the resistance of thymic cells to apoptosis, which will ultimately lead to defects and/or abnormal signaling by the interaction of thymic DC and thymocytes. Further studies involving such interactions are under way.


A rare case of grade IV frostbite is presented resulting in bilateral below knee amputations. This case highlights the importance of early versus late amputation as well as the importance of close collaboration between the rehabilitation, surgical, psychosocial, and public health disciplines in this rare and challenging problem that still may be encountered in the United Kingdom. This is the case of a 50-year old homeless man who sustained grade IV frostbite injuries to both feet after sleeping out in sub-zero temperatures. The patient first presented with ischaemic feet with well demarcated areas around the ankle Figure . The feeDelayed amputation had a positive effect on psychological acceptance of bilateral amputations by the patient as well as preparation for rehabilitation.Bilateral below-knee amputations are rarely performed. The predisposing factors include diabetic foot sepsis, atherosclerosis, frostbite, burns, trauma, calciphylaxis-related gangrene, suicide attempt, sensory loss and calf-wound healing failure after coronary revascularisation ,2. One oFrostbite can be graded into stages I to IV depending on tissue depth involvement. Two main approaches can be adopted with deep frostbite, either (a) early necrectomy with subsequent local treatment of wounds and (b) long-term conservative treatment until formation of demarcation line of necrotic tissue with subsequent resection and formation of a stump to facilitate rehabilitation.This case highlights the importance of careful consideration of early versus late amputation as well as the importance of close collaboration between the rehabilitation, surgical, psychosocial, and public health disciplines in this rare and challenging problem that still may be encountered in the United Kingdom.Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.The author declares that he has no competing interests.MJR is the sole author to this article and has written and researched the case himself.


We present an 82-year-old woman with a 3-month history of progressive dysphagia and a normal initial upper gastrointestinal endoscopy. The diagnosis of pseudoachalasia was suspected by oesophageal manometric and barium swallow studies, and confirmed by biopsies revealing an intestinal type carcinoma of the stomach at a repeated endoscopy. In view of the history of heart disease, diabetes, and old age, this patient was treated by a partially covered Ultraflex self-expanding metal stent  placed into the oesophageal body with no direct complications and obtaining the relief from dysphagia. During the 11-month follow-up she was treated for an iron deficiency anaemia due to reflux oesophagitis with ulcerations in the oesophageal body and died from myocardial infarction. According to the localization of the cancer, the old age, and the presence of comorbidities, we should recommend the insertion of a partially covered self-expanding metal stent as a reasonable palliative treatment in selected subjects with pseudoachalasia. Pseudoachalasia was firstly recognized by Ogilvie in 1947 due to the involvement of the distal oesophagus, with submucosal infiltration of the lower oesophageal sphincter (LES) and cardia by a carcinoma as the most usual cause –6. It miAn 82-year-old white woman was referred to our Unit with a 3-month history of dysphagia initially for solids, then also for liquids, and weight loss. She was diagnosed with diabetes and heart failure with arrhythmia because of a mitral valve insufficiency 10 years before. An upper endoscopy performed elsewhere 3 months before showed a normal oesophagus and gastrooesophageal junction. She was unsuccessfully treated with a 1-month course of proton pump inhibitors (PPIs) because of the suspicion of a nonerosive reflux disease. To rule out the diagnosis of achalasia we initially performed an oesophageal manometry, which showed loss of peristalsis in the oesophageal body, but it failed to investigate the LES function because the manometric catheter could not be passed across the cardia. Thereafter, a barium swallow study found a dilated oesophagus containing some food residue with an irregular tapered narrow cardia. At this point a new upper endoscopy confirmed a dilated oesophagus containing food. Moreover, by pushing hard the scope through the narrow cardia, a mild irregularity of the cardia mucosa was evident. Biopsies revealed an intestinal cell type carcinoma. To assess the extent of the cancer, a CT scan was performed, disclosing only the thickening of the gastric wall confined to the cardia without evidence of metastasis. Neither surgical treatment nor radiotherapy or chemotherapy were considered suitable in such a patient with a long history of diabetes and heart disease, whereas the insertion of self-expanding metal stent was optioned as a low risk procedure to rapidly improve her quality of life. We chose the Ultraflex self-expanding midsection covered distally releasing oesophageal metal stent  because it provided the most favourable results as far as stent placement, migration, long-term relief of dysphagia, and occurrence of fewer complications –18. The stent had a length of 7 cm, with an 18 mm diameter of the body and its flared proximal end 23 mm, and consisted of a knitted nitinol wire tube with a polyurethane layer, which covered the midsection of the stent, and it was distally released under fluoroscopic control . The proPseudoachalasia is a rare entity, which has only been described in a small subgroup of patients (5%) with two patterns of malignant tumor infiltrating the mucosa at the cardia. The most common type consists of malignant stricture of the cardia which acts as a physical barrier to the passage of food. A less frequent type is strictly related to the malignant submucosal infiltration with secondary impairment of oesophageal postganglionic LES innervations, maintaining the manometric pattern of achalasia stable even after treatment . Pseudoachalasia may be difficult to diagnose because multiple diagnostic procedures may fail to indicate the neoplastic origin . In partIn the pseudoachalasia the removal of the obstruction at the cardia by either surgery and/or chemotherapy and/or radiation may often allow the return of normal peristalsis into the oesophagus . HoweverRecently, the use of expandable oesophageal metal stents have been proposed as additional therapeutic option in achalasia and in a few cases of pseudoachalasia when the other palliative options, that is, oesophageal dilation or surgery or botox, failed. Moreover, temporary use of self-expanding metal stents have been used for benign oesophageal stenosis and fistula in patients who failed other conventional treatments –27. DespAs far as the use of oesophageal metal stents in pseudoachalasia is concerned, data are scanty and basically disappointing  25]. Ba. Ba25]. In conclusion, the insertion of a self-expanding metal stent into the oesophageal body should be proposed in particular types of pseudoachalasia caused by a cancer at the cardia when a short-life expectancy is presumed or other therapeutic approaches are impracticable.


Teratomas of anterior mediastinum are rare tumors and are often slow growing, asymptomatic and detected incidentally on chest imaging. Results of surgical resection are very satisfactory.A 19-years old male presented with an asymptomatic cystic neck mass. X-ray and CT scan of chest and neck showed an extrathyroidal multi-septate, predominantly cystic neck mass, that was continuous with a solid intrathoracic mass extending up to the level of right atrium and which contained areas of calcification and cystic necrosis. The mediastinal structures did not show any features of compression or infiltration. Fine needle aspiration cytology from the neck mass was suggestive of a dermoid cyst. In view of the extent and uncertain pathological nature of the tumor, it was excised via a combined cervical and trans-sternal route. Histo-pathology of the resected specimen confirmed the diagnosis of a mature cystic teratoma. The patient made an uneventful recovery, and after five years of follow-up, he has been symptom free with no clinical or radiological evidence of recurrent disease. We discuss the role of imaging and the need for surgical treatment to avoid possible catastrophic complications in patients with cervical and mediastinal masses of uncertain histological nature.A mediastinal teratoma may rarely present as a cystic neck swelling due to its cephalad extension. This entity needs to be considered in cases where clinical and investigative work-up fail to provide a convincing clue to a primary neck pathology as cause of a cystic neck swelling. Teratomas of the anterior mediastinum account for 8–13% of tumors in this region -4. TheseWe report the case of a young adult male who presented with a cystic neck mass, due to degeneration of a cervical extension of a mature teratoma of the anterior mediastinum. This is an unusual presentation of an uncommon pathology.A 19 years old male presented with a rapidly progressing painless neck swelling of 3 months duration. There were no complaints of fever or weight loss or symptoms suggestive of compression of adjacent structures. The patient was afebrile and had a cystic, non-tender, non-translucent and smooth swelling occupying the whole of the neck anteriorly, extending from the hyoid bone to the suprasternal notch. The lower limit of the swelling could not be reached. There were no neck nodes or dilated tortuous neck or chest wall veins.99mTc-thyroid scan ruled out a thyroid lesion. Contrast enhanced CT of neck and mediastinum  declare that they have no competing interests.GA conceived the case report, contributed to collection of clinical details and writing, reviewing and finalization of the manuscript; DKK prepared the first draft besides contribution to collection of clinical details and illustrations. Both authors reviewed and finally approved the final manuscript.Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.


In 1988, the SPILI project was established in order to evaluate the cardiovascular disease (CVD) risk profile of the inhabitants of Spili, in rural Crete, Greece. The first reports from this project revealed that against the unfavourable risk factors' profile observed, only a few men with a previous myocardial infarction were encountered. A follow-up study (SPILI II) was performed twelve years after the initial examination, and the unfavourable cardiovascular risk profile was re-confirmed.This paper presents a hypothesis formulated on the basis of previous research to investigate if dynamic psycho-social determinants, including social coherence of the local community, religiosity and spirituality, are protective against the development of coronary heart disease in a well-defined population.A follow-up examination of this Cretan cohort is currently being performed to assess the link between psychosocial factors and CVD. Psychosocial factors including sense of control, religiosity and spirituality are assessed in together with conventional CVD risk factors. Smoking and alcohol consumption, as well as dietary habits and activity levels are recorded. Oxidative stress and inflammatory markers, as well as ultrasound measurement of carotid intima media thickness, a preclinical marker of atherosclerosis, will also be measured.The issue of the cardio-protective effect of psycho-social factors would be revisited based on the results of this Cretan cohort; nevertheless, further research is needed across different sub-populations in order to establish a definite relationship. A comprehensive approach based on the aspects of bio-social life may result in more accurate CVD risk management. Cardiovascular disease (CVD) represents the leading cause of mortality in both the industrialised and developing world . Major rIn 1988, a research project was launched, aiming to explore the cardiovascular risk profile of the inhabitants of Spili in rural Crete, Greece . The stuA follow-up study was performed twelve years after the initial examination , with the aim of describing the trends of CHD risk factors over time and discussing some key points on the natural course of the disease (SPILI II) . The tarThis article illustrates potential links between dynamic psycho-social determinants  and coronary heart disease in a well-defined population sub-group on Crete with the aim to formulate a new Cretan hypothesis and discuss the design of a further ongoing follow-up study.Certain studies have attempted an explanation for the low CHD incidence on Crete, with a main focus on the Mediterranean diet . Furtherand Streptoe discussed certain mechanisms through which social and psychological factors impact on coronary atherogenesis, and inflammation was among these , markers of diabetes , markers of inflammation  ,26, as wDietary patterns (MedDietScore) , activitSpecific attention will be given to the social coherence of the local community  and theiA further dimension will be added to the study by the performance of interviews with a sample of the cohort, which could provide additional insight into the qualitative findings. This could represent an opportunity to capture informants' understandings and explanations of their personal experiences of religiosity, spirituality and social coherence accessed within the context of a group defined by geography and common culture.Incidence rates of CHD and related risk factors will be calculated as the ratio of new cases developed during the preceding years to the number of person-years. Continuous variables will be presented as mean values ± standard deviation and categorical variables will be presented as frequencies. Associations between categorical variables will be tested using the chi-squared test. Comparisons of mean values of normally distributed variables between those who developed a CVD event and the rest of the participants will be performed using Student's t-test. For the continuous variables that were not normally distributed, the Mann-Whitney non-parametric test will be applied to evaluate the differences in the distributions of the skewed variables between those who developed a CVD event and the remaining participants. Cox PH models with first order interactions will be estimated to test the potential mediating effect of bio-social aspects on the effect of the traditional CVD risk factors on CVD incidence. Sample size calculation revealed that to assess a log{hazard ratio} equal to 0.08 (or hazard ratio = 1.20) with a standard deviation of 1.5, a sample of 550 cases is needed in order achieve 80% power at a 0.05 significance level (two sided hypotheses) .Approval for this study was obtained by the Institutional Ethics Committee of the University Hospital of Crete (No Protocol:9989/02.09.2008). Written informed consent will be obtained from all participants. The anonymity of the patients' data will be carefully approached. The collected data will be stored at the Clinic of Social and Family Medicine, School of Medicine, University of Crete in which will be accountable from any public access.The current proposed study aims to explore the extent to which Cretan individuals with greater sense of coherence and high religiosity and spirituality levels, are less likely to be affected by chronic inflammation and atherosclerosis related burden and abnormal levels of the relative bio-markers examined.The findings will help researchers further explore possible links between biological and psychosocial health determinants. The study could also provide further evidence on the association of other factors such as the Mediterranean diet, which may explain a part of the CVD variation in the population studied. To achieve this, carefully designed research efforts are required in order to explore hypothetical patho-physiological pathways (direct and indirect) through which dynamic psycho-social determinants exert a protective biological effect and counterbalance a negative bio-profile. Furthermore, future interventions and health promotion programmes which take into consideration not only classical cardiovascular morbidity determinants  but also adverse psycho-social risk factors may influence our understanding of CVD features in relation to its presentation and natural history. The proposed study may provide an explanation of the so-called "Cretan paradox", by interpreting a range of factors, which may have contributed to the low CVD incidence on the island of Crete during the last decades .and Streptoe underline, it is often difficult to isolate the effects of independent psychosocial variables because they interact and tend to cluster together [A weakness of the proposed study is the inevitably small population size and time related losses with regard to follow-up, since this group has already been monitored for almost two decades. Furthermore, we cannot easily reject or adopt scenarios such as the presence of other confounding factors due to genetic patterns within the study population and the beneficial effects of Christian Orthodox fasting on serum lipids and obesity. As Strike together .In this collaborative proposal, researchers intend to return to the Spili cohort and link biological, psycho-social and socio-cultural data into an overarching model that may provide a clearer understanding of how biological and psycho-social determinants of health intersect and impact on morbidity. The Spili cohort presents a rare opportunity to build on an already solid body of research by way of asking broader questions regarding the relevance of traditional practices and cultural heritage on morbidity and mortality at the individual and community level. We anticipate that certain patterns will be identified which could have both immediate applicability for current clinical and public health concerns, and which may also generate a new round of research questions with regard to the significance of the community for the health and well-being of the individual.The authors declare that they have no competing interests.CL conceived and shaped the idea. DA, EKS and CL prepared the first draft of the manuscript. DP provided intellectual input and information on future statistical analysis. SS corrected the manuscript and provided useful suggestions on content, together with editorial support. EC provided scientific and technical input. All authors read and approved the final manuscript.


Various treatment options for the prosthetic treatment of jaws where all molars are lost are under discussion. Besides the placement of implants, two main treatment types can be distinguished: replacement of the missing molars with removable dental prostheses and non-replacement of the molars, i.e. preservation of the shortened dental arch. Evidence is lacking regarding the long-term outcome and the clinical performance of these approaches. High treatment costs and the long time required for the treatment impede respective clinical trials.This 14-center randomized controlled investigator-initiated trial is ongoing. Last patient out will be in 2010. Patients over 35 years of age with all molars missing in one jaw and with at least both canines and one premolar left on each side were eligible. One group received a treatment with removable dental prostheses for molar replacement (treatment A). The other group received a treatment limited to the replacement of all missing anterior and premolar teeth using fixed bridges (treatment B). A pilot trial with 32 patients was carried out. Two hundred and fifteen patients were enrolled in the main trial where 109 patients were randomized for treatment A and 106 for treatment B. The primary outcome measure is further tooth loss during the 5-year follow-up. The secondary outcome measures encompassed clinical, technical and subjective variables. The study is funded by the Deutsche Forschungsgemeinschaft .The particular value of this trial is the adaptation of common design components to the very specific features of complex dental prosthetic treatments. The pilot trial proved to be indispensable because it led to a number of adjustments in the study protocol that considerably improved the practicability. The expected results are of high clinical relevance and will show the efficacy of two common treatment approaches in terms of oral health. An array of secondary outcome measures will deliver valuable supplementary information. If the results can be implemented in the clinical practice, the daily dental care should strongly profit thereof.The trial is registered at ClinicalTrials.gov under ISRCTN68590603  and ISRCTN97265367 . Tooth loss is the consequence of the most common oral diseases caries and periodontitis -3. It of• no prosthetic treatment if the shortened dental arch is complete up to the second premolar• the restoration of a shortened dental arch up to the second premolar with crowns and bridges on natural teeth or dental implants (no replacement of the molars)• the replacement of missing molars with implant-retained crowns and bridges• the replacement of missing molars with removable dental prostheses (RDPs) of various designs.The minimum treatment with a preservation or restoration of the shortened dental arch was described by Käyser as the shortened dental arch (SDA) concept in 1981 . This co(1) higher rates of temporomandibular disorders(2) tooth migration, overeruption and increased wear(3) insufficient chewing efficiency and performance(4) compromised aesthetics -11.Missing teeth can be replaced using implant-retained restorations, tooth-borne bridges, and RDPs. Dental professionals consider the replacement of missing posterior teeth with implants a No. 1 choice especially with regard to the prevention of bone loss after tooth loss . The acc"The randomized shortened dental arch study" (RaSDA) was designed to evaluate the efficacy of the treatment with RDPs for molar replacement (treatment A) compared to the treatment limited to the replacement of all missing anterior and premolar teeth by means of fixed bridges (treatment B). Both treatment approaches chosen are considered as acceptable dental care. In many ways, shortened dental arches are borderline conditions in terms of the differential indication between fixed and removable restorations. Therefore, they are an ideal field to gather comparable data on the clinical performance of these fundamentally differing treatment concepts.This study was designed as a randomized multi-center trial. It will be reported according to the CONSORT statement . The stu▪ World's Medical Association's Declaration of Helsinki▪ International Organization for Standardization/European Standard (ISO/EN 540), Clinical Investigation of Medical Devices for Human Subjects, and▪ Guidelines of Good Clinical Practice in Europe, July 1995http://www.zahnreihe.de. The study design was approved by the Ethics Commission of the Medical Faculty Carl Gustav Carus of the Technical University Dresden (processing number: EK 260399).A consensus concerning all design aspects including treatment and dental laboratory procedures, basic dental materials, data collection, length, and frequency of the follow-ups was achieved and gathered in a detailed protocol. A manual describes the two treatment concepts in detail and is also available at the study homepage The enrollment period for the pilot study was originally set to 6 months. A total of 78 patients should have been enrolled within this time. However, this target patient number could not be reached even after a prolongation. The enrollment phase for the pilot trial started in December 2000 and was finished in October 2001. Diagnostic measures commonly used in clinical dentistry were applied in the pilot study  or grade 2 of the anamnestic Helkimo Index ,23▪ malocclusion of Angle class 2 or 3 with distal bite or mesial bite > one premolar width▪ ongoing orthodontic treatment▪ intention to undergo orthodontic treatment▪ clinically acceptable prosthetic status▪ rejection of RDPs▪ request of complete molar replacement▪ general health according to American Society of Anesthesiologists' (ASA) classification > 2 Dental schools in Germany interested in clinical research were contacted describing the aims and the scope of the trial. Fourteen prosthetic departments of dental schools and one biometrical center joined the trial. The study team consists of the principle investigator, his deputy responsible for quality control, and the treatment coordinator. Every participating dental clinic appointed a local investigator and a dentist responsible for all treatment measures. The patients were recruited from the clientele of the according dental schools. All patients exhibiting a suitable dental status and requesting dental treatment were considered eligible for participation.Two treatment groups were defined:Treatment A: Molars were replaced. This replacement was conducted by means of an RDP. A conventional cast framework retained by precision attachments (Mini SG No. 055 675) was supplemented with acrylic teeth. The male part of the attachment was part of a splinted crown or bridge retainer crown on the posterior-most tooth on each side. Retainer crowns were manufactured as porcelain fused to high noble metal crowns. If anterior teeth or first premolars were missing, they were replaced by bridges. If the second premolar was missing, this tooth was replaced by the RDP Fig. .Treatment B: Molars were not replaced. No prosthetic treatment was performed if the shortened dental arch was complete up to the second premolar. Any missing tooth up to the second premolar was replaced with tooth-borne bridges with or without cantilevers Fig. .In most cases, an appropriate pretreatment had to precede the final prosthetic phase. After completion of the pretreatment, the following conditions had to be achieved:▪ all abutment teeth are either sound or had successfully undergone a periodontal treatment . If necessary, the opposing jaw was restored with fillings, crowns, bridges, or RDPs. In the opposing jaw, the missing teeth were replaced at least up to the first molar (treatment A) or up to the second premolar (treatment B) in order to achieve adequate occlusion.All restorations were made according to a standardized operating procedure (SOP) given by the study protocol. Common high noble alloys and common dental porcelain materials were used for the fixed restorations; non-precious alloys were chosen for the frameworks of the removable denture. The local investigator supervised the treatment procedure and had to give his/her approval prior to the final insertion.The specific objective of this trial was to gain reliable outcome data with regard to different treatment options in SDA cases considering a multidimensional understanding of health. The study focused on general factors as tooth loss and treatment failure as well as on psychic aspects and aspects related to the patients' quality of life. Specific dental and oral factors encompassed caries, periodontitis, temporomandibular disorders, and aesthetics. In addition, technical factors  were included. The hypothesis was that the outcomes of treatments A and B would differ.The primary and secondary outcome measures are listed in Table Independent experts in the fields of periodontology, cariology and TMD performed the training and calibration of the local investigators and dentists responsible for treatment measures. During the first calibration meeting, videos demonstrating the clinical procedures were recorded and made available to all participating clinics. The information is also available on the study homepage in a password-protected area.Both the dentist and the local investigator were trained to complete the data forms in a defined order to ensure data integrity. The clinical training and the calibration comprised the collection of the measurable biological parameters (pocket depths etc.) and the assessment and scoring of the softer variables related to the condition of the prostheses and aesthetics. For the quality assessment of the prosthetic appliances, the quality evaluation criteria of the California Dental Association (CDA)  were adaThe analysis and the discussion of the pilot study results took place at an international workshop held in October 2001 in Dresden. Based on the results and experience gained during the pilot study, conclusions were drawn and changes in the study design were made.The baseline examination was performed 4 to 8 weeks after the insertion of the prosthetic restorations by external investigators chosen randomly among the investigators of the other participating dental schools. The examinations had to be pooled to reduce the traveling costs. Approximately 10% of the patients were examined twice on a random basis by both the local and the external investigator. This applied also to all follow-up examinations.The outcome measure "further tooth loss" required a sufficient number of patients in order to yield significant results in the primary efficacy analysis offering a high probability. In the course of the determination of the sample size, the number of the potentially eligible patients at the participating clinics per year was determined. Due to the small number of suitable patients, only a multi-site approach could provide an adequate number of participating patients. Furthermore, to ensure an impartial sampling, it was necessary to involve as many centers as possible.Calculating the necessary number of patients to be treated, a two-year recruitment period and a five-year follow-up period were scheduled. During the follow-up, the expected tooth loss was presumed to reach 20% with treatment A and 5% with treatment B -15, and The randomization was performed using randomly permuted blocks for each dental clinic with stratification into two age groups: up to 50 years und above 50 years of age.The randomization concealment was warranted because the randomization was conducted centrally after the patient enrollment phase.The data of any potentially eligible patient, who contacted one of the participating study centers, were documented during the screening process. Once a patient had given his/her informed consent, the data forms with clinical findings and treatment planning were sent to the treatment coordinator (TC). The TC checked the data regarding their conformity with the study protocol and sent a randomization request to the biometrical center. Finally, the TC forwarded the randomization results to the dental clinics.Due to the visible discrepancy of the treatments, neither the dentist nor the patient could be blinded.All statistical analyses are intended to be performed on the basis of the intention-to-treat principle, i.e. according to the patient's randomized treatment allocation regardless of any later protocol violations. In order to assure that treatment groups are balanced and provide structural equality, baseline patient characteristics will be compared between groups. For the primary outcome measure, Kaplan-Meier survival analyses will be performed. The Mantel-Cox log-rank test will be applied to test the null hypothesis of the equal progression of tooth loss in both treatment groups. This particular hypothesis test constitutes the primary study result and provides confirmatory statistical evidence. In order to quantify to what extent the risk to lose teeth differs between the treatment groups, the hazard ratio will be estimated on the basis of a univariate proportional hazards model. Beyond the primary analysis, analyses of prespecified secondary outcome measures will be performed. In further exploratory analyses, possible prognostic factors of tooth loss will be identified applying the multivariate Cox regression as well as classification and regression tree (CART) analyses.Descriptive analyses generally comprise the calculation of location and scale statistics (mean and standard deviation) as well as rates of target events. Point estimates will be supplemented by 95% confidence intervals. Inductive statistical analyses will be performed using appropriate significance tests. In order to compare both treatment groups with respect to quantitative measures, the Mann-Whitney U test will be applied, and Fisher's exact test will be used for the qualitative factors. The statistical analyses will be performed by means of the software packages SPSS  and SAS .The enrollment for the pilot study was stopped at 36 patients, with 19 patients randomized for therapy A and 17 randomized for therapy B. Three patients dropped out after the randomization; in one of these cases, the treatment had been performed already. Two hundred and fifteen patients were enrolled in the main trial, with 109 patients randomized for treatment A and 106 for treatment B Fig. . The folTraditionally, the treatment decisions in dentistry were based on empirical knowledge and in-vitro investigations of dental materials. During the last decade, clinical trials were carried out more frequently. However, high-level evidence is lacking regarding many treatment-related questions in dentistry due to:(1) controversial opinions concerning feasible outcome measures in clinical studies ,(2) long observation periods, particularly for the research in restorative dentistry,(3) high treatment expenses and laboratory costs, and(4) difficulties with regard to randomization and blinding respectively.The aim of the majority of studies in restorative dentistry was to prove whether or not a treatment can be considered effective. The outcome measures used in dentistry usually focused on technical failures  so far. Some studies considered biological aspects, for example periodontal condition and need of endodontic treatment. In recent years, the evaluation of patient-related factors and the oral health related quality of life have been gaining importance. While the majority of the previous studies had a retrospective design and relatively limited variable sets, this trial is aiming at a more comprehensive evaluation of the prosthetic treatment. This approach required the collection of a large-scale variable set. However, some of the very specific examinations used in the pilot study proved to be less meaningful than expected. Furthermore, it was difficult to train some of the respective diagnostic measures Table . A multiDiscussions at the international symposium held after the recruitment phase of the pilot study revealed the treatment workflow as further cause for the limited number of patients recruited. The pilot study protocol demanded a completed pretreatment  before randomization. The pretreatment sometimes required the removal of existing restorations without being able to give the patient a clear treatment perspective. Therefore, the treatment workflow was changed to randomization at an earlier stage.Clinical trials on the long-term outcomes of prosthetic treatments are extremely costly and time-consuming. The observation periods required are long. The complexity of the prosthetic treatment measures and the common allocation practice with regard to the differential indication of fixed versus removable restorations  turn theThe most important confounders in prosthetic treatment studies are the dentists themselves, the applied treatment principles, and the treatment environment. The multi-center approach involving almost half of the German dental schools and the extensive training of the dentists are considered appropriate to reduce this bias and appear to be suitable to deliver results that are representative for the basic conditions of German dental-schools.The main inclusion criteria define a certain topography where all molars are missing in one jaw and at least both canines and one premolar are present on each side Fig. . This isFollowing the holistic approach, clinical findings were applied that are commonly used in the daily practice. Only few diagnostic measures applied in clinical dentistry have been validated  including the possibility to gather clinical data in a reproducible way and, thus, allow the calibration of the clinical investigators. In general, surrogate parameters as caries and attachment loss have widely been used in prosthetic treatment studies. They are suitable to deliver relatively early results and were, therefore, included as secondary outcome measures. However, tooth loss as the irreversible sequel of the main dental diseases has a high reliability and a high impact on health and was, therefore, chosen as a very viable indicator of oral health.The study can be considered as one of the most comprehensive randomized trials in prosthetic dentistry. The design with its basic principles established the basis for clinical research in restorative dentistry on a contemporary level. Considering the basic aim of the trial, it was vital to focus on those clinical findings that might offer an explanation for the success or failure of a treatment concept, the occurrence of TMD, and, not least important, patient satisfaction.ASA: American Society of Anesthesiologists; CART: Classification and Regression Trees; CDA: California Dental Association; DFG: Deutsche Forschungsgemeinschaft (German Research Foundation); EN: Europäische Norm (European Standard); ISO: International Organization for Standardization; OHIP: Oral Health Impact Profile; RaSDA: The Randomized Shortened Dental Arch Study; RDP: Removable Dental Prosthesis; RDPs: Removable Dental Prostheses; SDA: Shortened Dental Arch; SOP: Standardized Operating Procedure; TC: Treatment Coordinator; TMD: Temporomandibular Disorders.The authors declare that they have no competing interests.RL made substantial contributions to the conception and design and was involved in drafting the manuscript. MW is the principal investigator. BM made substantial contributions to the acquisition of data. MW and BM were involved in drafting the manuscript. AH and JG accomplished the statistical consultancy and computation, JG was also involved in drafting the manuscript. HA, EB, PD, IG, SH, and FJ made substantial contributions to the acquisition of data. WH, MK, TM, PP, HS, and MW made substantial contributions to the conception and design. GH made substantial contributions to the acquisition of data and to the analysis and interpretation of data. BW made substantial contributions to the conception and design and provided the data base to enter the data of the study into SPSS. HA, EB, PD, IG, AH, SH, WH, FJ, MK, TM, PP, and HS were involved in critically revising the manuscript. All authors read and approved the final manuscript.


Investigation of the risk of fracture of the polyethylene (PE) inlay in constrained total knee prostheses.Three unused and seven polyethylene inlays that had been implanted in a patient's knee for an average of 25.4 months  were investigated using scanning electron microscopy (SEM). All inlays were of the same type and size . The PE surface at the transition from the plateau to the post was analyzed.The unused inlays had fissure-free surfaces. All inlays that had been implanted in a patient's knee already had distinct fissures at the front and backside of the post.The fissures of the transition from the plateau to the post indicated a loading-induced irreversible mechanical deformation and possibly cause the fracture of the inlay. Due to the growing number of revision total knee arthroplasties, posterior stabilized and constrained total knee prostheses have become more and more popular in recent years. They allow intrinsic stabilization in knees with ligamentous instability. So far, clinical results of constrained total knee arthroplasty (TKA) have been reported only in medium-term follow-up . NeverthPosterior stabilized total knee prostheses that are similar in design to constrained prostheses also tend to increasing axis deviations and inlay breakage after a few years, especially in patients with severe preoperative axis deviation of the leg axis of more than 10° in the coronal plane . SeveralDue to the increasing deviation of the mechanical leg axis and breakage of the post, the post has to be regarded as the weak point of the constrained total knee joint arthroplasty, where the tibial post is not reinforced with a metal rod. From the mechanical point of view, however, the transition between the post and the femoral cam cause extensive loads on the post and occurs as a weak point of this design. This proved to be a serious problem with constraint prostheses, which are expected to provide a higher stability and tolerate these acting forces. The following investigation of unloaded and loaded constraint polyethylene inlays was performed to elucidate initially this problem in polyethylene inlays without metal rod reinforcement.Ten polyethylene inlays were investigated using scanning electron microscopy. All inlays were of the same type and size. The model used was an 11 mm thick constrained inlay of the Genesis II total knee . The size is called "5–6" which is identical for sizes 5 and 6 of the tibial component. The inlays consist exclusively of ultrahigh-molecular weight polyethylene  without any metal reinforcement and were formed by milling to its final shape. All inlays were sterilized by gas sterilization using ethylene oxide.Three polyethylene inlays were unused and acted as controls. The samples were subsequently prepared according to a standardized preparation protocol, mentioned below.2 .Seven inlays had been retrieved from patients, four men and three women, with a constrained prosthesis during revision surgery. The mean age of the patients was 66.4 years . The patients had a body mass index at the time of surgery of 31 kg/cmAll UHMWPE inlays were retrieved during second revision TKA. The first revision was carried out for aseptic loosening in four cases, septic loosening in one case, and mediolateral instability in two cases. In this first revision, a condylar constrained implant was used for reconstruction. After a period of in average 25.4 months after the first revision , a second revision was necessary. The reasons for the second revision were aseptic loosening in three cases, deep infection in two cases and in two cases a painful combined medial and lateral instability. Preoperatively, the patients showed no significant deviation of the mechanical axis in coronal plane and had no trauma in their history.The retrieved implants were cleaned with sterile water and afterwards prepared according to the same preparation protocol applied to the other inlays.The polyethylene inlays, which have an overall size of about 75 mm mediolateral, 50 mm posteroanterior and a height of 36 mm Fig. , had to Imaging was performed on a scanning electron microscope (SEM) S-450  with secondary electrons (SE) at 20 keV and at room temperature ,12. The The scanning electron microscopic investigations of the unused inlays showed typical traces and small unevenness on the surface caused by the milling-treatment during the manufacturing process. These traces occur on the entire surface area of the inlay. The SE-micrographs did not show microfissures in the material Fig.  and 3. IAll inlays that had been explanted from a patient's knee showed clefts and some micro-fissures. Especially the corners or the tibial post showed polyethylene damage. The anteromedial corner corresponds to the location 12/1 Fig.  and 5h. The exemplary scanning electron microscopy investigations demonstrated significant differences between the unused and the loaded inlays in a patient's knee. These findings support the hypothesis that load-induced damaging of PE-inlays in constrained total knee prostheses preferentially occur in the transition zone where the tibial post merges into the plateau of the PE-inlay. Mainly the zones at the ventral and dorsal corners of the tibial post showed distinct serious micro-fissures and micro-clefts after load application after implantation in a short-term follow-up. Hence, it can be assumed that this region involves a certain danger of fracture. Even these micro-fissures potentially can expand to macroscopic fissures of the post or may become regions of preferential polyethylene wear. If they can act as a predetermined breaking point of the post must be evaluated in further examinations. The small number and only a qualitative analysis of examined inserts could not elaborate the main mechanism for the observed damages in our collective.Reports already described the problem of the fracture of the tibial post in different posterior-stabilized knee arthroplasties ,6,7. A sAnymore movement in the normal knee joint contained a combination of rolling and sliding of the femoral condyles on the tibial plateau . RollingFinally, other specific factors like the patient's height, weight and activity, the surgical technique considering soft tissue preservation and alignment, the design of the prosthesis, its quality, the mechanical processing of the form, the thickness, the kind of sterilization of the polyethylene inlay as well as the polyethylene itself play also an important role. Muratoglu et al.  could shWith this investigation we furthermore would like to point out that scanning electron microscopy enables a local inspection of surfaces. Therefore different types of defects like micro-fissures or scratches having a size far below 1 μm can be detected as well as be characterized. Obviously, this is a unique advantage over rather simple macroscopic methods like microabrasive wear testing of UHMWPE  in casesThis investigation demonstrates that PE inlays of constrained total knee prostheses have a weak point at the zone where the post merges into the plateau. Already short periods of weight bearing cause significant damage inform of micro-fissures and clefts especially at the post corners and the posterior area. Particularly, in overweight patients as well as in patients with ligamentous insufficiency, a mechanically more solid PE-inlay is required. Furthermore, an extended examination of the patient after a constraint total knee arthroplasty with the symptoms of unknown discomfort, persistent effusion of the joint, instability or deviation of the leg axis should be performed because of a suspicion of a PE inlay failure.Further investigations are needed to find out if lower acting loads can cause a tibial post breakage in polyethylene inlays with this demonstrated damage. Also the role of rotational forces and ligament insufficiencies must be evaluated in following studies.polyethylene: PE; scanning electron microscopy: SEM; secondary electrons: SE; total knee arthroplasty: TKA; ultra-high-molecular weight polyethylene: UHMWPE; nanometers: nm; micrometers: μm; kilo electron volt: keV.The authors declare that they have no competing interests.AS participated in the design of the study, collected patients' inlays and data, drafted the manuscript. COT participated in the design of the study, collected patients' inlays and data, drafted the manuscript and revised the manuscript for grammar and content. RR participated in the design of the study, performed the scanning electron microscopy with his assistants, helped to draft the manuscript and revised the manuscript for grammar and intellectual content. SF–W participated in the design of the study, was responsible for the organization of the study, helped to draft the manuscript and revised the manuscript for intellectual content.The pre-publication history for this paper can be accessed here:


Diversity in rates of gene expression is essential for basic cell functions and is controlled by a variety of intricate mechanisms. Revealing general mechanisms that control gene expression is important for understanding normal and pathological cell functions and for improving the design of expression systems. Here we analyzed the relationship between general features of genes and their contribution to expression levels.Genes were divided into four groups according to their core promoter type and their characteristics analyzed statistically. Surprisingly we found that small variations in the TATA box are linked to large differences in gene length. Genes containing canonical TATA are generally short whereas long genes are associated with either non-canonical TATA or TATA-less promoters. These differences in gene length are primarily determined by the size and number of introns. Generally, gene expression was found to be tightly correlated with the strength of the TATA-box. However significant reduction in gene expression levels were linked with long TATA-containing genes  whereas intron length hardly affected the expression of TATA-less genes. Interestingly, features associated with high translation are prevalent in TATA-containing genes suggesting that their protein production is also more efficient.Our results suggest that interplay between core promoter type and gene size can generate significant diversity in gene expression. The wide range of gene expression levels in the cell is strictly controlled by a variety of complicated mechanisms. Major contributors to gene expression rates are DNA regulatory elements that vary between individual genes. Among these sequences key roles are played by specific combinations of enhancer elements and their binding factors. Revealing additional features that influence gene expression level is central to understanding how cells work and what has been changed in diseased states.A common element important to the overall expression level of the gene is the core promoter. The core promoter is located around the transcription start point and serves as the site of pre-initiation complex formation by RNA polymerase II and general transcription factors . The TATTo examine whether there is a link between promoters and general features of genes, we first used the DBTSS to retrieve promoters with verified TSSs and analyzed them for their core promoter type according to the presence/absence of a minimal canonical TATA box (TATAWA) at the expected location (-40 to -15 relative to the TSS)  of median gene length   Fig.  and 1D. -45) , their introns or both. To examine this we compared lengths of mRNAs and introns in the TATA, TATA-1, TATA-2 and TATA-less groups. The results show small but highly significant differences in the median mRNA length between the TATA containing groups Fig.  and 1D. 45) Fig.  and 1D wWe next determined the number of exons in the different groups and here again we found the exon number is inversely correlated with the strength of the TATA box Fig.  and 2D. While the core promoter is well known for its critical role in transcription, much less is known about the impact of intron size on gene expression. A previous analysis revealed that short introns are correlated with high expression levels . HoweverWe first determined the average expression of each gene in all tissues, setting a threshold value of 200, a value that is above background. Then we determined the 25%, median and 75% quartile of the average expression for each group Fig. . Since aThe overall level of expression correlates well with the strength of the TATA box as the expression is gradually increased with the compatibility to the TATA box consensus Fig. . Thus itThe effect of intron length on expression was determined by dividing each group into genes with short or long introns. As the TATA gene set has the shortest introns we defined genes whose intron length was less than the median intron length of the TATA (~8000) as short Fig. . A notabIn addition we see that the advantage of having a TATA core promoter for expression is more significant for genes bearing short introns compared to genes with long introns. For instance, the median expression of short intron genes in the TATA group is 3–4 fold higher than short intron genes from TATA-2 or TATA-less groups, but this advantage is reduced to only 1.6 fold in long genes. It therefore appears that for the TATA groups  both the strength of the TATA box and the intron length strongly influence expression. By contrast, genes with TATA-less promoters are weakly expressed regardless of their intron length. It is likely that these genes have specific features that overcome the negative effect of long introns.Given that general features such as core promoter and gene size act together to affect the levels of mRNA production, we next wished to test whether there is a link between core promoter type and protein translation efficiency. Although mRNA and protein levels are generally correlated -23, therThe statistical analysis of structural and functional features of mammalian genes associated with core promoter variants revealed surprisingly close ties between different steps of gene expression from transcription initiation and elongation to protein production. These findings extend further the links found in yeast between core promoter type and features that are seemingly not directly associated with transcription initiation such as gene function , evolutiThe most remarkable observation of the statistical analysis of genes divided according to their core promoters is that small variations relative to the TATA-box consensus are associated with large differences in gene length as a consequence of intron size and number. Specifically genes containing canonical TATA were found to be significantly shorter than genes bearing non-canonical TATA or TATA-less promoters. Analysis of expression of genes in the different groups highlighted several points. First, the level of expression is highly correlated with the strength of the TATA box confirming previous gene-specific studies showing that deviations from the TATA consensus reduce transcription -18. SecoGiven the high cost of transcription, extending intron size in higher eukaryotes must be beneficial. Varying intron size and core promoter type may be an economic way for utilizing the same cellular constituents to modulate gene expression levels. In addition large introns with small exons may serve to reduce mutational rate in coding sequences (dilution effect). This possibility is consistent with the observations from yeast that TATA containing genes evolve at a higher rate ,14.The mechanistic basis underlying the links between core promoter and gene length remains to be investigated but is likely to involve RNA polymerase II, an entity present both in the core promoter and throughout the gene. Our previous findings that core promoter variants dictate recruitment of different elongation factors upon activation by NF-κB, through formation of distinct pre-initiation complexes , provideH. sapiens genes appearing in the DBTSS version 6, with experimentally-determined transcription start site (TSS), were used in the current study. The genes were divided into groups according to their core promoter type. Core promoters with a minimal canonical TATA box (TATA), a TATA-box with one mismatch (TATA-1), a TATA-box with two mismatches (TATA-2) and the remainder of the genes (TATA-less) comprised the four gene groups. Our criteria demanded that the TATA motif (TATAWA) and its alternatives were strictly located between -40 and -15 with respect to the TSS. Using the 'pattern matching' tool of the Regulatory Sequence Analysis Tools (available on the internet) we were able to direct each gene to its appropriate group. The TATA, TATA-1, TATA-2 and TATA-less groups finally comprised 527, 694, 3916 and 9491 genes respectively.The 14,728 Genes were classified according to their function using the gene-annotation enrichment analysis (DAVID Bioinformatics Resources 2007). The data of the various gene features were retrieved from the UCSC genome browser March 2006 assembly. In this browser we used the 'Tables' to obtain coordinates of different tracks  in order to calculate the following features: gene length, mRNA length, intron length, exon number, 5' UTR length and 3' UTR length with the Excel program. UCSC Table Browser was also used to retrieve DNA sequences of the translation initiation site of each mRNA which was scanned for the presence of the Kozak motif (RNNAUGG).Gene expression data (gcRMA) for each group of genes was downloaded from SymAtlas v1.2.4 (available on the internet at the Novartis Research Foundation site). For each gene only the major probe set was used. Expression values below 200 were considered background and omitted from the analysis. The average and maximum expression values of each gene were calculated. Genes were then divided into two sets according to their intron size (less or more than 8000 nt) and the median, 25% and 75% quartiles of average expression of each set were determined and are presented as boxplots.The range of measurements for each gene feature within the groups was wide, making it statistically inappropriate to compare their means, particularly since we did not wish to exclude any gene that did not appear to fit the general observed pattern. We therefore determined the 25%, median and 75% quartile values for the different features. We measured the significance of the differences between the median values (6 groups) by the Kruskal-Wallis test with the Bonferroni correction using the Statistics Toolbox of the MATLAB program (The MathWorks). The Spearman's rank correlation coefficient analysis between expression levels and intron size was performed using the MATLAB program. The likelihood of there being significant differences between the groups regarding the absence of introns and the presence of the Kozak motif sequences was calculated using the Chi-square test.SM participated in the design of this study, performed the bioinformatic and statistical analyses of the various gene features and wrote this paper. RE participated in the bioninformatic analysis of core promoters. MG performed the bioinformatic analysis of the gene expression data. HS participated in the intellectual and statistical analyses. RD conceived the study, participated in its design, analyzed the data and wrote the paper. All authors read and approved the final manuscript.A. The gene sets were divided into all (white bars) short  or long genes , and the median of the maximal expression for each gene set is shown. The numbers show the fold change between short and long in each group. B. The p-values of the differences in the median value between each two gene sets as indicated. NS is non-significant difference (p > 0.05).Analysis of the maximal expression level in gene sets. Click here for file


SIRS (susceptible-infectious-recovered-susceptible) infection dynamics in a very large (assumed infinite) population of households, with the simplifying assumption that each household is of the same size . For this households model we present efficient methods for studying several quantities of epidemiological interest: (i) the threshold for invasion; (ii) the early growth rate; (iii) the household offspring distribution; (iv) the endemic prevalence of infection; and (v) the transient dynamics of the process. We utilize these methods to explore a wide region of parameter space appropriate for human infectious diseases. We then extend these results to consider the effects of more realistic gamma-distributed infectious periods. We discuss how all these results differ from standard homogeneous-mixing models and assess the implications for the invasion, transmission and persistence of infection. The computational efficiency of the methodology presented here will hopefully aid in the parameterisation of structured models and in the evaluation of appropriate responses for future disease outbreaks.Early mathematical representations of infectious disease dynamics assumed a single, large, homogeneously mixing population. Over the past decade there has been growing interest in models consisting of multiple smaller subpopulations , with the natural assumption of strong homogeneous mixing within each subpopulation, and weaker transmission between subpopulations. Here we consider a model of  The earliest models proposed for infectious disease dynamics assumed that the population afflicted by the pathogen was large and homogeneously mixed such that deterministic equations with simple frequency-dependent transmission were appropriate Household structured models offer an attractive trade-off between fine-scale detail and computational feasibility, and for this reason they increasingly form the basis of studies in disease management. For example, it has been known for some time that household structure influences the critical threshold for invasion and vaccination SIRS (susceptible-infected-recovered-susceptible) model. We model the spread of such a pathogen amongst individuals occupying a very large (assumed infinite) set of households. The infection dynamics within each household is captured by a Markov chain representation, accounting for the stochastic effects due to the small number of individuals within each household. We assume that transmission between households results from (effective) contacts between individuals in the population occurring at a fixed rate. Models of this form have been studied widely recently Here we consider a pathogen for which individuals develop transient immunity following infection, with the immunity waning resulting in the individual eventually returning to full-susceptibility to the disease: the In this paper we investigate a range of epidemiologically important quantities over a large region of parameter space; as such we present and utilise efficient methods for evaluating these quantities. Some of the methods we adopt have been described elsewhere, and alternative methods exist for evaluating several of the quantities. In particular the classic work on households models such as Malthusian parameterFive epidemiologically important quantities are evaluated: (i) the threshold for invasion, SIR model). We then proceed to apply this methodology to our structured households models to investigate the impact of household size, within- and between-household transmission rates, rate of waning immunity, and infectious period distribution on dynamics. We conclude by discussing the general implications of our results.In the next section we introduce the basic model of within- and between-household transmission, before detailing the methodology adopted, and illustrate several of the techniques with respect to a model for households of size one  distribution of secondary infections: the offspring distribution is Poisson with random mean, and the probability density function of the mean is Now, for future use, consider the distribution of the path integral. We have from (2): Malthusian parameter of the branching process approximation of Ball et al.Finally, we consider the early growth rate We now turn our attention to evaluating each of the desired quantities for households of arbitrary, but homogeneous, size. Populations of mixed household sizes are achievable through the same basic methodology, but the ensuing behaviour is more difficult to visualise and the relationships to the distribution of household sizes is naturally more complex. When dealing with household dynamics we initially consider a Markov chain model of an epidemic occurring within the initially infected household, effectively setting The household basic reproduction number fzero routine.The early growth rate The household offspring distribution during the early stages of the epidemic is again Poisson with random mean:To evaluate the endemic prevalence, we could evaluate the full transient dynamics of the process, as explained in the next section, and evaluate the endemic prevalence via convergence to equilibrium of these dynamics. However, it is possible to develop a more efficient procedure, which does not rely on numerically solving the differential equations.eig, we find the eigenvector corresponding to the zero eigenvalue; normalised to sum to We exploit the fact that at equilibrium the rate of import of infection into a household, ode45.To model the full dynamics of the system we need to both include the external rate of infection method of stages: the infectious class is decomposed into several sub-classes, with an identical rate of transition between these classes chosen to retain the same expected infectious period. Such an approach maintains the Markov property of the underlying model and thus the applicability of the methodology outlined above  in the first we hold the transmission rate parameter Examining the critical level of between-household transmission (Plot 1A) indicates that two factors contribute to the success of an infection. For large household sizes, the main determinant of epidemic success is whether within-household transmission  shows a significant probability that a newly infected household will fail to infect any further households; often because the infection fails to spread within the household. This failure probability is relatively unaffected by the waning immunity rate, The complete model dynamics at a given parameter set (Plot 1E) demonstrates that our methods for calculating early growth (green line) and the endemic state (blue line) are sound, and also that the proportion of households with a given prevalence assumes a unimodal distribution around the mean, with significant variance.With respect to the critical transmission rate, With respect to the offspring distributions (C), once again the incorporation of gamma-distributed infectious period, and choice of what is held constant between epidemics, has a significant impact. In both cases the probability of no secondary households infected decreases, and by a substantial margin in the case of Finally, we consider the influence of gamma-distributed infectious period, and what is held constant, by studying the full dynamics of infection. Holding SIRS disease paradigm. Solutions of the kind we have found provide a useful bridge between formal work In this paper, we have focused on appropriate numerical methods for efficient calculation of epidemiologically relevant quantities in households models obeying an In essence the behaviour of the households model can be explained by two different processes. Firstly, compared to purely individual-based transmission Click here for additional data file.File S2Calculation of disease dynamics in a population of households. In this Supporting Information File S2 we provide MATLAB code.(0.01 MB ZIP)Click here for additional data file.


Surface plasmon resonance imaging and surface plasmon induced fluorescent are sensitive tools for surface analysis. However, existing instruments in this area have provided limited capability for concurrent detection, and may be large and expensive. We demonstrate a highly cost-effective system capable of concurrent surface plasmon resonance microscopy (SPRM) and surface plasmon resonance-enhanced fluorescence (SPRF) imaging, allowing for simultaneous monitoring of reflectivity and fluorescence from discrete spatial regions. The instrument allows for high performance imaging and quantitative measurements with surface plasmon resonance, and surface plasmon induced fluorescence, with inexpensive off-the-shelf components. Laboratories in the developing world may be severely resource-constrained in terms of funding, physical infrastructure, and high-end technical support personnel Surface plasmons are charge density-oscillations created at the interface of two media with dielectric constants of different signs, for example between a noble metal and glass. The resonance of these surface plasmons can occur when the wavevector of p-polarized light incident upon an interface matches the wavevector of the surface plasmons; this matching of wavevectors is characterized by a drop in the photon flux reflected from the interface. Fields associated with surface plasmons extend into the media surrounding the interface and decay exponentially, and are thus sensitive to changes in the media around them The schematic of our system is shown in −4 RI units; this is a useful range, in that such a change in RI can be created by less than 5% of a monolayer of bovine serum albumin (BSA) adsorbed to the surface To calibrate the SPR microscopy system response to different refractive indices (RI) present over the metal surface, we measured the changes in reflectivity with changes in RI utilizing a protocol established previously in our laboratory In order to test the linearity of the fluorescence system with dye concentrations, a Mylar flowcell was assembled over a freshly cleaned Au-coated slide as mentioned above. Different concentrations of Alexa Fluor 647 non-reactive dye were prepared through serial dilutions and passed through the flowcell, from which fluorescence intensity measurements were taken. Apart from the SPRF, the fluorescence signal may have a strong component caused by scattered light. To measure the contribution of any scattered light, the angle of the prism was tuned to be just off the resonance angle, and the drop in fluorescence intensity measured. We observed the scattering to be less sensitive to small changes in angle compared to the SPRF signal (data not shown). Thus difference between the fluorescence intensities at resonance (SPRF + scattering) and just off-resonance (scattering) allows the determination of the fraction of the fluorescence signal due to scattering (∼35%); this was subtracted from our fluorescence measurements. The results from the calibration experiments are illustrated in In conclusion, an instrument capable of concurrent surface plasmon resonance microscopy and surface plasmon resonance-enhanced fluorescence imaging has been constructed and demonstrated. Whilst sensitive independent instruments are available with these capabilities, our instrument uniquely provides both these capabilities in one compact and highly cost-effective unit. Potential uses include point-of-care diagnostics and lab-on-a-chip applications for global health, where the quantitation of labelled and unlabelled proteins on the same device may be necessary and cost efficacy is highly relevant.


Nonagenarians and centenarians represent a quickly growing age group worldwide. In parallel, the prevalence of dementia increases substantially, but how to define dementia in this oldest-old age segment remains unclear. Although the idea that the risk of Alzheimer's disease (AD) decreases after age 90 has now been questioned, the oldest-old still represent a population relatively resistant to degenerative brain processes. Brain aging is characterised by the formation of neurofibrillary tangles (NFTs) and senile plaques (SPs) as well as neuronal and synaptic loss in both cognitively intact individuals and patients with AD. In nondemented cases NFTs are usually restricted to the hippocampal formation, whereas the progressive involvement of the association areas in the temporal neocortex parallels the development of overt clinical signs of dementia. In contrast, there is little correlation between the quantitative distribution of SP and AD severity. The pattern of lesion distribution and neuronal loss changes in extreme aging relative to the younger-old. In contrast to younger cases where dementia is mainly related to severe NFT formation within adjacent components of the medial and inferior aspects of the temporal cortex, oldest-old individuals display a preferential involvement of the anterior part of the CA1 field of the hippocampus whereas the inferior temporal and frontal association areas are relatively spared. This pattern suggests that both the extent of NFT development in the hippocampus as well as a displacement of subregional NFT distribution within the Cornu ammonis (CA) fields may be key determinants of dementia in the very old. Cortical association areas are relatively preserved. The progression of NFT formation across increasing cognitive impairment was significantly slower in nonagenarians and centenarians compared to younger cases in the CA1 field and entorhinal cortex. The total amount of amyloid and the neuronal loss in these regions were also significantly lower than those reported in younger AD cases. Overall, there is evidence that pathological substrates of cognitive deterioration in the oldest-old are different from those observed in the younger-old. Microvascular parameters such as mean capillary diameters may be key factors to consider for the prediction of cognitive decline in the oldest-old. Neuropathological particularities of the oldest-old may be related to “longevity-enabling” genes although little or nothing is known in this promising field of future research. The rapid growth of the world population's oldest-old age segment has prompted awareness of age-related diseases including dementia as well as considerable interest in the study of the aging human brain. By 2020, people older than 60 years will account for more than 20% of the total population with those individuals reaching very old ages corresponding to the fastest growing age group worldwide. Rare at the beginning of the 20th century in Switzerland with about 650 people aged 90 or more, a steady increase occurred with a total of 2000 oldest-old persons by 1945. Near exponential growth of this oldest-old group occurred after 1945 with the total number of oldest-old citizens amounting to 47000 by 2001, that is, a multiplication of 25 in 56 years [Our ancestral fascination for extreme aging and the steady increase of the number of centenarians worldwide prodded the research community to look into psychobiological particularities of the “longevity outliers”. The known socio demographic predictors of mortality such as smoking and obesity are less important in this age group –11. CentLife expectancy with or without incapacity has increased markedly: some subjects may remain independent for long periods into older age while others require help and care over extended periods of their lives. In Switzerland, the proportion of persons living in nursing homes increases from only 5% for those below 80 years to 40% for those between 90 and 94 years of age. Dementia clearly contributes to this reality. However, it remains unclear how to define dementia in the frail oldest-old and what it means to be a dementia-free centenarian despite the claim of some researches that up to a quarter of all centenarians may be cognitively intact , 18. ThuBrain aging is characterized by the formation of neurofibrillary tangles (NFTs) and senile plaques (SPs) as well as neuronal and synaptic loss in both cognitively intact individuals and patients with AD. The first cited diagnostic criteria for AD were intended to aid in the development of uniform procedures by proposing minimally required SP densities as a function of age , 35. TheWhile the definite diagnosis of AD is based on neuropathological criteria, the clinical diagnosis of probable and possible AD in clinical settings is usually made according to the NINCDS-ADRDA criteria . TypicalIn terms of clinicopathological correlations, several lines of evidence indicate that the primary progressive amnestic syndrome so characteristic of the initial stages of typical AD is the consequence of the neuropathological changes in the medial temporal structures, in particular the entorhinal cortex and the hippocampus. Although there is still ongoing controversy as to the exact roles of these structures in cognition, they are likely to be important in encoding new information –52. The Most of the above studies have not included very old subjects. The question, thus, arises whether or not the pattern of lesion distribution and neuronal loss changes in extreme aging. A recent study using the CERAD criteria for neuropathological diagnosis found a progressive increase of moderate to severe AD-type pathology with age in subjects between 69 and 103 years in those without dementia . In the The magnitude of neuronal loss in the entorhinal cortex and CA1 field in older subjects was significantly lower than that reported in younger AD cases , 72, 73.Strong relationships between NFT counts and neuron loss in the hippocampal formation and neocortex have been reported and suggest that neuronal loss is NFT-dependent . However3 versus 100–800 mm3) [Unlike younger cohorts where SP formation does not correlate with neuronal depletion and cognitive status –81, both800 mm3) . As mentioned above, the association between AD-type pathology and dementia, in a cohort of 456 subjects between 69 and 103 years was stronger in the younger old persons than in the older old ones . Oldest-Several cases with minimal AD pathology and preserved cognitive functions , 33, 67,Indeed, neuritic dystrophy  may be aSynaptic loss may be an important factor . RecentlIn the longitudinal Oregon Brain Aging study, NFT and SP densities in neocortical areas were significantly related to cognitive scores . Overt cThe controversy over the continuity versus discontinuity between normal brain aging and dementia goes on. The hypothesis that AD is an ageing-related condition is supported by the nearly ubiquitous presence of AD pathologic changes in the course of brain aging and the exponential increase of AD prevalence after 65 years of age. However, contrasting with this view of the aging process, the study of oldest-old individuals indicates that the occurrence of AD pathology is not a mandatory phenomenon of increasing chronologic age. In particular, the neuropathology of advanced aging strongly suggests that very old individuals with AD display a striking resistance to the neurodegenerative process with only mild neuronal loss in the hippocampal formation. Our hospital-based findings support a dissociation between the clinical expression and traditionally assessed AD pathology. These findings are consistent with the recent neuropathological observations of the New England Centenarian Study , 113 andThe biological background of the increased resistance to AD lesion development after 90 years is still poorly understood. Oldest-old people may show genetic variations that influence basic mechanisms of brain aging resulting in a decreased susceptibility to age-associated diseases . In part