Combining allele frequency uncertainty and population substructure corrections in forensic DNA calculations

In forensic DNA calculations of relatedness of individuals and in DNA mixture analyses, at least two sources of uncertainty are present concerning the allele frequencies used for evaluating genotype probabilities when evaluating likelihoods. They are: (i) imprecision in the estimates of the allele frequencies in the population by using an inevitably finite database of DNA profiles to estimate them; and (ii) the existence of population substructure. Green and Mortera [6] showed that these effects may be taken into account individually using a common Dirichlet model within a Bayesian network formulation, but that when taken in combination this is not the case; however they suggested an approximation that could be used. Here we develop a slightly different approximation that is shown to be exact in the case of a single individual. We demonstrate the numerical closeness of the approximation using a published database of allele counts, and illustrate the effect of incorporating the approximation into calculations of a recently published statistical model of DNA mixtures.     

Surveillance of patients with gastric precancerous conditions

Intestinal-type gastric adenocarcinoma arises from a multistep process starting with Helicobacter pylori infection followed by gastric atrophy, gastric intestinal metaplasia and dysplasia.Indeed, patients with gastric precancerous conditions or lesions (GPC) are at increased risk to develop gastric cancer even in regions with low incidence. Thus, the identification and surveillance of a high risk subgroup could lead to the diagnosis of cancer at early stage and improve survival. However, both endoscopic and histological accuracy and interobserver agreement in the diagnosis of GPC are still far from optimal. Also, there are conceptual differences between the West and the East in the diagnosis and surveillance of patients. In the former, multiple gastric biopsies are still recommended but Eastern gastroenterologists select patients to surveillance according to the results of endoscopy or serology.In this literature review we describe the cascade of GPC and we highlight the differences between eastern and western clinical practice.     

The Association between the Low Muscle Mass and Osteoporosis in Elderly Korean People

The purpose of this study was to predict osteoporosis risk as decreasing muscle mass and to declare the cut-off value of low muscle mass in an elderly Korean population. This study was based on data from the 2008-2010 Korea National Health and Nutritional Examination Surveys (KNHANES). The subjects included 1,308 men and 1,171 women over 65 yr. Bone mineral density (BMD) and appendicular skeletal muscle (ASM) were measured by dual energy X-ray absorptiometry (DXA), and appendicular skeletal muscle was adjusted by height as a marker of sarcopenia. After confirming the correlation between low muscle mass and BMD, the best cut-off value of muscle mass to estimate osteoporosis was suggested through the receiver operating characteristic (ROC) curve. For both men and women, BMD correlated positively with low muscle mass when ASM/Ht² was used as a marker for sarcopenia. The ROC curve showed that ASM/Ht² was the best marker for osteoporosis at a cut-off value of 6.85 kg/m² for men and 5.96 kg/m² for women. When these cut-off values were used to determine sarcopenia, the risk of osteoporosis increased 4.14 times in men and 1.88 times in women. In particular, men (OR 2.12) with sarcopenia were more greatly affected than women (OR 1.15), even after adjusting for osteoporosis risk factors. In elderly Korean people, sarcopenia is positively correlated with BMD and there is a strong correlation between sarcopenia and osteoporosis with risk of bone fracture.     

Alcohol as a Risk Factor for Cancer: Existing Evidence in a Global Perspective

The purpose of the present review is to give an overview of the association between alcohol intake and the risk of developing cancer. Two large-scale expert reports; the World Cancer Research Fund (WCRF)/American Institute of Cancer Research (AICR) report from 2007, including its continuous update project, and the International Agency for Research of Cancer (IARC) monograph from 2012 have extensively reviewed this association in the last decade. We summarize and compare their findings, as well as relate these to the public health impact, with a particular focus on region-specific drinking patterns and disease tendencies. Our findings show that alcohol intake is strongly linked to the risk of developing cancers of the oral cavity, pharynx, larynx, oesophagus, colorectum (in men), and female breast. The two expert reports diverge on the evidence for an association with liver cancer and colorectal cancer in women, which the IARC grades as convincing, but the WCRF/AICR as probable. Despite these discrepancies, there does, however, not seem to be any doubt, that the Population Attributable Fraction of alcohol in relation to cancer is large. As alcohol intake varies largely worldwide, so does, however, also the Population Attributable Fractions, ranging from 10% in Europe to almost 0% in countries where alcohol use is banned. Given the World Health Organization’s prediction, that alcohol intake is increasing, especially in low- and middle-income countries, and steadily high in high-income countries, the need for preventive efforts to curb the number of alcohol-related cancers seems growing, as well as the need for taking a region- and gender-specific approach in both future campaigns as well as future research. The review acknowledges the potential beneficial effects of small doses of alcohol in relation to ischaemic heart disease, but a discussion of this lies without the scope of the present study.     

公共场所集中空调通风系统现场采样释义

近年来,公共场所内的集中空调越来越深受人们的欢迎。其通风系统现场样品采集样是监测工作的前提基础和关键控制点,为提高现场采样工作的效率,确保采集样品具有代表性,根据在现场采样的实际工作遇到的问题,从采样前期准备、现场采集、采样后贮藏等方面对公共场所集中空调通风系统现场采样进行探讨。     

Measures of initiation and progression to increased smoking among current menthol compared to non-menthol cigarette smokers based on data from four U.S. government surveys

There are no large-scale, carefully designed cohort studies that provide evidence on whether menthol cigarette use is associated with a differential risk of initiating and/or progressing to increased smoking. However, questions of whether current menthol cigarette smokers initiated smoking at a younger age or are more likely to have transitioned from non-daily to daily cigarette use compared to non-menthol smokers can be addressed using cross-sectional data from U.S. government surveys. Analyses of nationally representative samples of adult and youth smokers indicate that current menthol cigarette use is not associated with an earlier age of having initiated smoking or greater likelihood of being a daily versus non-daily smoker. Some surveys likewise provide information on cigarette type preference (menthol versus non-menthol) among youth at different stages or trajectories of smoking, based on number of days smoked during the past month and/or cigarettes smoked per day. Prevalence of menthol cigarette use does not appear to differ among new, less experienced youth smokers compared to established youth smokers. While there are limitations with regard to inferences that can be drawn from cross-sectional analyses, these data do not suggest any adverse effects for menthol cigarettes on measures of initiation and progression to increased smoking.     

Characterization of 114 insertion/deletion (INDEL) polymorphisms,and selection for a global INDEL panel for human identification

Bi-Allelic Insertions and Deletions (INDELs) are a powerful set of genetic markers for Human Identification (HID). They have certain desirable features, such as low mutation rates, no stutter, and potentially small amplicon sizes that could prove effective in some circumstances. In this study, we analyzed the distribution of 114 INDELs in four North American populations (Caucasian, African American, Southwest Hispanic, and Asian) to estimate their distribution in major global populations. Of the 114 INDELs a primary panel of 38 candidate markers was selected that met the criteria of (1) a minimum allele frequency of greater than 0.20 across the populations studied; (2) general concordance with Hardy–Weinberg equilibrium (HWE) expectations; (3) relatively low F_ST based on the major populations; (4) physical distance between markers greater than 40 Mbp; and (5) a lack of linkage disequilibria between syntenic markers. Additionally, another 11 supplemental markers were selected for an expanded panel of 49 markers which met the above criteria, with the exception that they are separated at least by 20 Mbp. The resulting panels had Random Match Probabilities that were at least 10⁻¹⁶ and 10⁻¹⁹, respectively, and combined F_ST values of approximately 0.02. Given these findings, these INDELs should be useful for HID.     

The Genetic Link Between Diabetes and Atherosclerosis

Epidemiological studies have indicated that the risk of atherothrombotic coronary artery disease (CAD) is higher in patients with diabetes, but these results have not been consistently observed across clinical trials. To address this apparent discrepancy, we can apply the results of genome-wide association studies (GWAS) to provide a better understanding of the shared genetic architecture of diabetes and atherothrombotic CAD. For instance, a large GWAS has identified 16 novel loci that are associated with both diabetes and atherothrombotic CAD. These genetic variants may also be used to assess potential causal relationships reported in observational studies and clinical trials through Mendelian randomization analyses. For example, several Mendelian randomization analyses have shown that diabetes is associated with CAD independent of other risk factors (odds ratio [OR]: 1.63, 95% confidence interval [CI]: 1.23–2.07; P = 0.002). Furthermore, Mendelian randomization analyses can provide more insight into the perceived risk of diabetes among patients without diabetes receiving statin therapy. Here, genetically lower activity of HMG-CoA reductase (HMGCR) was associated with a modest increase in diabetes (OR per allele: 1.02, 95% CI: 1.00–1.05). These results highlight the biological mechanisms that link diabetes with the use of statins. In addition, this work illustrates the great potential value of genetic studies to clarify the mechanistic relationships among atherosclerotic vascular disease, dysglycemia, and diabetes. More research is needed to delineate and subsequently better understand the genetic links between diabetes and atherosclerosis.