369 research outputs found

    Mutations in the EXT1 and EXT2 genes in hereditary multiple exostoses.

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    Hereditary multiple exostoses (EXT; MIM 133700) is an autosomal dominant bone disorder characterized by the presence of multiple benign cartilage-capped tumors (exostoses). Besides suffering complications caused by the pressure of these exostoses on the surrounding tissues, EXT patients are at an increased risk for malignant chondrosarcoma, which may develop from an exostosis. EXT is genetically heterogeneous, and three loci have been identified so far: EXT1, on chromosome 8q23-q24; EXT2, on 11p11-p12; and EXT3, on the short arm of chromosome 19. The EXT1 and EXT2 genes were cloned recently, and they were shown to be homologous. We have now analyzed the EXT1 and EXT2 genes, in 26 EXT families originating from nine countries, to identify the underlying disease-causing mutation. Of the 26 families, 10 families had an EXT1 mutation, and 10 had an EXT2 mutation. Twelve of these mutations have never been described before. In addition, we have reviewed all EXT1 and EXT2 mutations reported so far, to determine the nature, frequency, and distribution of mutations that cause EXT. From this analysis, we conclude that mutations in either the EXT1 or the EXT2 gene are responsible for the majority of EXT cases. Most of the mutations in EXT1 and EXT2 cause premature termination of the EXT proteins, whereas missense mutations are rare. The development is thus mainly due to loss of function of the EXT genes, consistent with the hypothesis that the EXT genes have a tumor- suppressor function

    Recommended conventions for reporting results from direct dark matter searches

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    The field of dark matter detection is a highly visible and highly competitive one. In this paper, we propose recommendations for presenting dark matter direct detection results particularly suited for weak-scale dark matter searches, although we believe the spirit of the recommendations can apply more broadly to searches for other dark matter candidates, such as very light dark matter or axions. To translate experimental data into a final published result, direct detection collaborations must make a series of choices in their analysis, ranging from how to model astrophysical parameters to how to make statistical inferences based on observed data. While many collaborations follow a standard set of recommendations in some areas, for example the expected flux of dark matter particles (to a large degree based on a paper from Lewin and Smith in 1995), in other areas, particularly in statistical inference, they have taken different approaches, often from result to result by the same collaboration. We set out a number of recommendations on how to apply the now commonly used Profile Likelihood Ratio method to direct detection data. In addition, updated recommendations for the Standard Halo Model astrophysical parameters and relevant neutrino fluxes are provided. The authors of this note include members of the DAMIC, DarkSide, DARWIN, DEAP, LZ, NEWS-G, PandaX, PICO, SBC, SENSEI, SuperCDMS, and XENON collaborations, and these collaborations provided input to the recommendations laid out here. Wide-spread adoption of these recommendations will make it easier to compare and combine future dark matter results

    Motorcyclists' reactions to safety helmet law: a qualitative study

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    <p>Abstract</p> <p>Background</p> <p>Extensive body of the literature reveals that proper use of helmets is an effective way to reduce the severity of injuries and fatalities among motorcyclists. However, many motorcyclists do not use safety helmet properly. This study aimed to empirically explore reactions of motorcyclists to the safety helmet laws, in Iran.</p> <p>Methods</p> <p>Qualitative data were collected via four focus groups and 11 in-depth interviews. Participants were 28 male motorcyclists who never used a safety helmet during rides, and 4 male police officers. All transcripts, codes and categories were read for several times to exhaust identifiable major themes. During this process data were reduced from text to codes and themes.</p> <p>Results</p> <p>Five major themes emerged from the data analyses, including themes related to the following: (1) circumventing or dodging police officers; (2) simulating a helmet wearing behavior; (3) accepting the probability of receiving a ticket; (4) taking advantage of the police neglect and carelessness; and (5) using a cheap or convenient helmet.</p> <p>Conclusion</p> <p>Our findings suggest certain levels of reckless driving among the participating motorcyclists in this study. They also point to a system of law enforcement that operates haphazardly and fails to consistently penalize those who deviate from it. Further studies are needed to investigate how "risks" are perceived and relate to "reactions", and how a 'culture of masculinity' may encourage risk tolerance and a disposition toward lawlessness and carelessness among male motorcyclists. Also, there is a need for the development and implementation of multidimensional interventions that would offer socio-culturally sensitive educational and motivational messages to the motorcyclists and the in-service traffic-enforcement officers in Iran.</p

    Changes in Weight, Waist Circumference and Compensatory Responses with Different Doses of Exercise among Sedentary, Overweight Postmenopausal Women

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    It has been suggested that exercise training results in compensatory mechanisms that attenuate weight loss. However, this has only been examined with large doses of exercise. The goal of this analysis was to examine actual weight loss compared to predicted weight loss (compensation) across different doses of exercise in a controlled trial of sedentary, overweight or obese postmenopausal women (n = 411).Participants were randomized to a non-exercise control (n = 94) or 1 of 3 exercise groups; exercise energy expenditure of 4 (n = 139), 8 (n = 85), or 12 (n = 93) kcal/kg/week (KKW). Training intensity was set at the heart rate associated with 50% of each woman's peak VO(2) and the intervention period was 6 months. All exercise was supervised. The main outcomes were actual weight loss, predicted weight loss (exercise energy expenditure/ 7700 kcal per kg), compensation (actual minus predicted weight loss) and waist circumference. The study sample had a mean (SD) age 57.2 (6.3) years, BMI of 31.7 (3.8) kg/m(2), and was 63.5% Caucasian. The adherence to the intervention was >99% in all exercise groups. The mean (95% CI) weight loss in the 4, 8 and 12 KKW groups was -1.4 (-2.0, -0.8), -2.1 (-2.9, -1.4) and -1.5 (-2.2, -0.8) kg, respectively. In the 4 and 8 KKW groups the actual weight loss closely matched the predicted weight loss of -1.0 and -2.0 kg, respectively, resulting in no significant compensation. In the 12 KKW group the actual weight loss was less than the predicted weight loss (-2.7 kg) resulting in 1.2 (0.5, 1.9) kg of compensation (P<0.05 compared to 4 and 8 KKW groups). All exercise groups had a significant reduction in waist circumference which was independent of changes in weight.In this study of previously sedentary, overweight or obese, postmenopausal women we observed no difference in the actual and predicted weight loss with 4 and 8 KKW of exercise (72 and 136 minutes respectively), while the 12 KKW (194 minutes) produced only about half of the predicted weight loss. However, all exercise groups had a significant reduction in waist circumference which was independent of changes in weight.(ClinicalTrials.gov) NCT00011193

    Genetic Basis of Growth Adaptation of Escherichia coli after Deletion of pgi, a Major Metabolic Gene

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    Bacterial survival requires adaptation to different environmental perturbations such as exposure to antibiotics, changes in temperature or oxygen levels, DNA damage, and alternative nutrient sources. During adaptation, bacteria often develop beneficial mutations that confer increased fitness in the new environment. Adaptation to the loss of a major non-essential gene product that cripples growth, however, has not been studied at the whole-genome level. We investigated the ability of Escherichia coli K-12 MG1655 to overcome the loss of phosphoglucose isomerase (pgi) by adaptively evolving ten replicates of E. coli lacking pgi for 50 days in glucose M9 minimal medium and by characterizing endpoint clones through whole-genome re-sequencing and phenotype profiling. We found that 1) the growth rates for all ten endpoint clones increased approximately 3-fold over the 50-day period; 2) two to five mutations arose during adaptation, most frequently in the NADH/NADPH transhydrogenases udhA and pntAB and in the stress-associated sigma factor rpoS; and 3) despite similar growth rates, at least three distinct endpoint phenotypes developed as defined by different rates of acetate and formate secretion. These results demonstrate that E. coli can adapt to the loss of a major metabolic gene product with only a handful of mutations and that adaptation can result in multiple, alternative phenotypes

    The importance of iron in long-term survival of maintenance hemodialysis patients treated with epoetin-alfa and intravenous iron: analysis of 9.5 years of prospectively collected data

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    <p>Abstract</p> <p>Background</p> <p>In patients treated by maintenance hemodialysis the relationship to survival of hemoglobin level and administered epoetin-alfa and intravenous iron is controversial. The study aim was to determine effects on patient survival of administered epoetin-alfa and intravenous iron, and of hemoglobin and variables related to iron status.</p> <p>Methods</p> <p>The patients were 1774 treated by maintenance hemodialysis in 3 dialysis units in New York, NY from January 1998 to June, 2007. A patient-centered, coded, electronic patient record used in patient care enabled retrospective analysis of data collected prospectively. For survival analysis, patients were censored when transplanted, transferred to hemodialysis at home or elsewhere, peritoneal dialysis. Univariate Kaplan-Meier analysis was followed by multivariate analysis with Cox's regression, using as variables age, race, gender, major co-morbid conditions, epoetin-alfa and intravenous iron administered, and 15 laboratory tests.</p> <p>Results</p> <p>Median age was 59 years, epoetin-alfa (interquartile range) 18,162 (12,099, 27,741) units/week, intravenous iron 301 (202, 455) mg/month, survival 789 (354, 1489) days. Median hemoglobin was 116 (110, 120)g/L, transferrin saturation 29.7 (24.9, 35.1)%, serum ferritin 526 (247, 833) μg/L, serum albumin 39.0 (36.3, 41.5) g/L. Survival was better the higher the hemoglobin, best with > 120 g/L. Epoetin-alfa effect on survival was weak but had statistically significant interaction with intravenous iron. For intravenous iron, survival was best with 1–202 mg/month, slightly worse with 202–455 mg/month; it was worst with no intravenous iron, only slightly better with > 455 mg/month. Survival was worst with transferrin saturation ≤ 16%, serum ferritin ≤ 100 μg/L, best with transferrin saturation > 25%, serum ferritin > 600 μg/L The effects of each of hemoglobin, intravenous iron, transferrin saturation, and serum ferritin on survival were independently significant and not mediated by other predictors in the model.</p> <p>Conclusion</p> <p>Long term survival of maintenance hemodialysis patients was favorably affected by a relatively high hemoglobin level, by moderate intravenous iron administration, and by indicators of iron sufficiency. It was unfavorably influenced by a low hemoglobin level, and by indicators of iron deficiency.</p

    The First Sequenced Carnivore Genome Shows Complex Host-Endogenous Retrovirus Relationships

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    Host-retrovirus interactions influence the genomic landscape and have contributed substantially to mammalian genome evolution. To gain further insights, we analyzed a female boxer (Canis familiaris) genome for complexity and integration pattern of canine endogenous retroviruses (CfERV). Intriguingly, the first such in-depth analysis of a carnivore species identified 407 CfERV proviruses that represent only 0.15% of the dog genome. In comparison, the same detection criteria identified about six times more HERV proviruses in the human genome that has been estimated to contain a total of 8% retroviral DNA including solitary LTRs. These observed differences in man and dog are likely due to different mechanisms to purge, restrict and protect their genomes against retroviruses. A novel group of gammaretrovirus-like CfERV with high similarity to HERV-Fc1 was found to have potential for active retrotransposition and possibly lateral transmissions between dog and human as a result of close interactions during at least 10.000 years. The CfERV integration landscape showed a non-uniform intra- and inter-chromosomal distribution. Like in other species, different densities of ERVs were observed. Some chromosomal regions were essentially devoid of CfERVs whereas other regions had large numbers of integrations in agreement with distinct selective pressures at different loci. Most CfERVs were integrated in antisense orientation within 100 kb from annotated protein-coding genes. This integration pattern provides evidence for selection against CfERVs in sense orientation relative to chromosomal genes. In conclusion, this ERV analysis of the first carnivorous species supports the notion that different mammals interact distinctively with endogenous retroviruses and suggests that retroviral lateral transmissions between dog and human may have occurred

    Worldwide Distribution of the MYH9 Kidney Disease Susceptibility Alleles and Haplotypes: Evidence of Historical Selection in Africa

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    MYH9 was recently identified as renal susceptibility gene (OR 3–8, p<10−8) for major forms of kidney disease disproportionately affecting individuals of African descent. The risk haplotype (E-1) occurs at much higher frequencies in African Americans (≥60%) than in European Americans (<4%), revealing a genetic basis for a major health disparity. The population distributions of MYH9 risk alleles and the E-1 risk haplotype and the demographic and selective forces acting on the MYH9 region are not well explored. We reconstructed MYH9 haplotypes from 4 tagging single nucleotide polymorphisms (SNPs) spanning introns 12–23 using available data from HapMap Phase II, and by genotyping 938 DNAs from the Human Genome Diversity Panel (HGDP). The E-1 risk haplotype followed a cline, being most frequent within sub-Saharan African populations (range 50–80%), less frequent in populations from the Middle East (9–27%) and Europe (0–9%), and rare or absent in Asia, the Americas, and Oceania. The fixation indexes (FST) for pairwise comparisons between the risk haplotypes for continental populations were calculated for MYH9 haplotypes; FST ranged from 0.27–0.40 for Africa compared to other continental populations, possibly due to selection. Uniquely in Africa, the Yoruba population showed high frequency extended haplotype length around the core risk allele (C) compared to the alternative allele (T) at the same locus (rs4821481, iHs = 2.67), as well as high population differentiation (FST(CEU vs. YRI) = 0.51) in HapMap Phase II data, also observable only in the Yoruba population from HGDP (FST = 0.49), pointing to an instance of recent selection in the genomic region. The population-specific divergence in MYH9 risk allele frequencies among the world's populations may prove important in risk assessment and public health policies to mitigate the burden of kidney disease in vulnerable populations

    Ionizing radiation modulates human macrophages towards a pro-inflammatory phenotype preserving their pro-invasive and pro-angiogenic capacities

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    In order to improve the efficacy of conventional radiotherapy, attention has been paid to immune cells, which not only modulate cancer cell response to therapy but are also highly recruited to tumours after irradiation. Particularly, the effect of ionizing radiation on macrophages, using therapeutically relevant doses, is not well understood. To evaluate how radiotherapy affects macrophage behaviour and macrophage-mediated cancer cell activity, human monocyte derived-macrophages were subjected, for a week, to cumulative ionizing radiation doses, as used during cancer treatment (2Gy/fraction/day). Irradiated macrophages remained viable and metabolically active, despite DNA damage. NF-kappaB transcription activation and increased Bcl-xL expression evidenced the promotion of pro-survival activity. A significant increase of pro-inflammatory macrophage markers CD80, CD86 and HLA-DR, but not CCR7, TNF and IL1B was observed after 10Gy cumulative doses, while anti-inflammatory markers CD163, MRC1, VCAN and IL-10 expression decreased, suggesting the modulation towards a more proinflammatory phenotype. Moreover, ionizing radiation induced macrophage morphological alterations and increased their phagocytic rate, without affecting matrix metalloproteases (MMP)2 and MMP9 activity. Importantly, irradiated macrophages promoted cancer cell-invasion and cancer cell-induced angiogenesis. Our work highlights macrophage ability to sustain cancer cell activities as a major concern that needs to be addressed to improve radiotherapy efficacy

    Paradigms in multiple sclerosis: time for a change, time for a unifying concept

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    It has recently been suggested that, rather than being an autoimmune disease, multiple sclerosis (MS) is an example of a neurocristopathy, a pathological process resulting from a faulty development of the neural crest. Whilst several characteristics of the disease suggest a neurocristopathy, other aetiological factors require consideration, including hygiene-related factors that alter the immune responses to common pathogens resulting in an eclipse of immune reactivity that could protect against MS, the possible role of human endogenous retroviruses (HERVs) in pathogenesis and autoimmune phenomena, HLA polymorphism, vitamin D levels before and after birth and immune repair mechanisms. A postulated aetiological factor in MS, associated with altered vitamin D metabolism and abnormal HERV expression, is a long-lasting disturbed redox regulation in the biosynthesis of a melanoma-like melanin pigment. Although intensive further studies on melanin pigments in nerve tissue in MS are required, the known properties of a pathological form of such pigments in melanoma could explain a number of observations in MS, including the impact of light, UV-light, and vitamin D, and could explain the clinical manifestations of MS on the basis of an oscillating process of oxidative charge and discharge of the pigments and a threshold phenomenon with a change of the quasi-catalytic function of the pigment from destroying reactive oxygen radicals or species to transforming them to more harmful long-persisting highly reactive species. Taken together with the consequences of an adaptive process in partly demyelinated neurons, resulting in an increase in number of mitochondria, and the impact of stressful life events, these conditions are necessary and sufficient to explain the disease process of MS with its spatial (plaques) and temporal (attacks and remissions) characteristics. This suggested unifying concept of the pathogenesis of MS may open perspectives for prevention, diagnosis and therapy. In particular, prevention may be achieved by vaccinating against Epstein-Barr virus in early childhood
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