Community acquired Panton-Valentine Leukocidin (PVL) positive Methicilin Resistant Staphylococcal aureus cerebral abscess in an 11-month old boy: a case study.

BACKGROUND: Brain abscess are uncommon childhood infection. Brain abscess caused by Panton-Valentine Leukocidin positive Community acquired Methicillin Resistant Staphylococcal aureus have never been reported in the United Kingdom. CASE PRESENTATION: We report a case of a previously well 11-month old boy of Indian origin who developed a parietal lobe abscess from PVL positive CA-MRSA. CONCLUSION: This case is one of the few described cases of brain abscess caused by PVL CA-MRSA in children. The unusual (insidious) presentation, the absence of a clear staphylococcal focus and the unexpected finding of a CA-MRSA in this patient highlight the challenges of managing such cases in clinical settings and the potential future risk to public health

Unusual Structure of a Human Middle Repetitive DNA

The L2Hs sequences are a polymorphic, interspersed, middle repetitive DNA family unique to human genomes. Genomic fingerprinting indicates that these DNAs vary from one individual to another and between tissues of the same individual. Sequence analysis reveals that they are AT-rich (76%) and contain many unusual sequence arrangements (palindromes, inverted and direct repeats). These sequence properties confer on the L2Hs elements the potential to fold into non-B-form structures, a characteristic of recombination hot spots. To test this hypothesis carbodiimide, osmium tetroxide and S\sb1 nuclease were used as single-strand specific probes to study a recombinant plasmid, pN6.4.39, containing a single L2Hs segment. Different forms of the plasmid substrate were analyzed, including linear molecules and circular forms of low, intermediate and high superhelical densities. In addition, plasmid DNA in growing E. coli cells were analyzed. Modified plasmid DNA was analyzed by primer extension in a sequencing-type reaction format. These studies demonstrate that the L2Hs sequences: (1) assume non-B-form structures both in vitro and in vivo, (2) map to predicted cruciform structures, (3) behave as C-type extrusion sequences, and (4) that these unusual DNA structures are dependent on plasmid superhelicity

Optimization of the absorber layer thicknesses and the surface defect densities of CdTe/Si tandem device

In this research, the performance variation of a newly modeled tandem device was investigated. A thin-film photovoltaic tandem device was created with a CdS/CdTe top cell configuration and a thick Si bottom cell configuration. The goal of this numerical simulation study was to enhance the performance of the tandem photovoltaic device. Therefore several modifications and optimizations were done to the device structure. An Mg-doped ZnO-based (MZO) layer was used as a High Resistance Transparent (HRT) layer with a very thin CdS layer. The thickness of the CdS was reduced to minimize its parasitic absorption property. The top and the bottom cell models were developed by using a special script introduced in SCAPS-1D solar cell capacitance simulator software. An artificial surface defect layer (SDL) was introduced between the window and the absorber of the top cell. The optimization procedure was carried out by altering the thicknesses of the top and the bottom absorbers and also varying the defect concentrations of the CdS/SDL interface and SDL/CdTe interface. The current matching condition of the tandem device and the device performance under the AM1.5G spectrum were also investigated. As the outcomes, we have identified the minimum possible defect density concentrations required for the window to absorber interfaces of the top cell to achieve the optimum performance. The experimental research work is suggested to further confirm the modeling results of the tandem device structure. KEYWORDS: Thin-film, Tandem, Surface Defect Layer, Defect Density, Bandgap, SCAPS-1

Letter to the Editor: Presence of Evolutionary Pressures or Genotyping Error

I have read with great interest the recent study by Ryu et al., whic

Estimates of benefits and harms of prophylactic use of aspirin in the general population

Background: Accumulating evidence supports an effect of aspirin in reducing overall cancer incidence and mortality in the general population. We reviewed current data and assessed the benefits and harms of prophylactic use of aspirin in the general population. Methods: The effect of aspirin for site-specific cancer incidence and mortality, cardiovascular events was collated from the most recent systematic reviews. Studies identified through systematic Medline search provided data regarding harmful effects of aspirin and baseline rates of harms like gastrointestinal bleeding and peptic ulcer. Results: The effects of aspirin on cancer are not apparent until at least 3 years after the start of use, and some benefits are sustained for several years after cessation in long-term users. No differences between low and standard doses of aspirin are observed, but there were no direct comparisons. Higher doses do not appear to confer additional benefit but increase toxicities. Excess bleeding is the most important harm associated with aspirin use, and its risk and fatality rate increases with age. For average-risk individuals aged 50–65 years taking aspirin for 10 years, there would be a relative reduction of between 7% (women) and 9% (men) in the number of cancer, myocardial infarction or stroke events over a 15-year period and an overall 4% relative reduction in all deaths over a 20-year period. Conclusions: Prophylactic aspirin use for a minimum of 5 years at doses between 75 and 325 mg/day appears to have favourable benefit–harm profile; longer use is likely to have greater benefits. Further research is needed to determine the optimum dose and duration of use, to identify individuals at increased risk of bleeding, and to test effectiveness of Helicobacter pylori screening–eradication before starting aspirin prophylaxis

Numerical Investigation of the Best Efficient Tandem Solar Cell Structures Using the Base Cell Models of MZO/CdTe and CdS/CIGS Cell Structures

Tandem solar cells have been researched to enhance the performance of the second generation (II-VI) thin-film solar cells. In this study, we have developed an efficient tandem solar cell model by optimizing the thickness of the (II-VI) layers and by introducing Mg doped ZnO as the window material for the top cell. The tandem solar cell model consists of a top cell, n-MZO/p-CdTe and a bottom cell, n-CdS/p-Cu(In, Ga)Se2 (CIGS). The parameters of the computational model, such as thicknesses of n-CdS, p-CIGS. p-CdTe has been varied to improve the efficiency of the tandem solar cell and compared with the previous researched single junction thin-film solar cells. All the numerical experiments were conducted under one sun illumination condition with AM 1.5 G solar spectrum by using the Analysis of Microelectronic and Photonic Structures simulation software (AMPS-1D) and Solar Cell Capacitance Simulator (SCAPS 1-D) software. The observed open circuit voltage was 1.413 V and the efficiency wa sincreased to 28.84% and this is a huge improvement compared to the reported recorded best research cell values of 0.8 V and 24.2% respectively for single junction solar cell. KEYWORDS : AMPS-1D, SCAPS-1D, Tandem solar cell, II-VI photovoltaics, AM1.5G, Thin-film P

Association between Polymorphisms in Glutathione Peroxidase and Selenoprotein P Genes, Glutathione Peroxidase Activity, HRT Use and Breast Cancer Risk.

Breast cancer (BC) is one of the most common cancers in women. Evidence suggests that genetic variation in antioxidant enzymes could influence BC risk, but to date the relationship between selenoproteins and BC risk remains unclear. In this report, a study population including 975 Danish cases and 975 controls matched for age and hormone replacement therapy (HRT) use was genotyped for five functional single nucleotide polymorphisms (SNPs) in SEPP1, GPX1, GPX4 and the antioxidant enzyme SOD2 genes. The influence of genetic polymorphisms on breast cancer risk was assessed using conditional logistic regression. Additionally pre-diagnosis erythrocyte GPx (eGPx) activity was measured in a sub-group of the population. A 60% reduction in risk of developing overall BC and ductal BC was observed in women who were homozygous Thr carriers for SEPP1 rs3877899. Additionally, Leu carriers for GPX1 Pro198Leu polymorphism (rs1050450) were at ∼2 fold increased risk of developing a non-ductal BC. Pre-diagnosis eGPx activity was found to depend on genotype for rs713041 (GPX4), rs3877899 (SEPP1), and rs1050450 (GPX1) and on HRT use. Moreover, depending on genotype and HRT use, eGPx activity was significantly lower in women who developed BC later in life compared with controls. Furthermore, GPx1 protein levels increased in human breast adenocarcinoma MCF7 cells exposed to β-estradiol and sodium selenite.In conclusion, our data provide evidence that SNPs in SEPP1 and GPX1 modulate risk of BC and that eGPx activity is modified by SNPs in SEPP1, GPX4 and GPX1 and by estrogens. Our data thus suggest a role of selenoproteins in BC development

Decision Forest Analysis of 61 Single Nucleotide Polymorphisms in a Case-Control Study of Esophageal Cancer; a novel method

BACKGROUND: Systematic evaluation and study of single nucleotide polymorphisms (SNPs) made possible by high throughput genotyping technologies and bioinformatics promises to provide breakthroughs in the understanding of complex diseases. Understanding how the millions of SNPs in the human genome are involved in conferring susceptibility or resistance to disease, or in rendering a drug efficacious or toxic in the individual is a major goal of the relatively new fields of pharmacogenomics. Esophageal squamous cell carcinoma is a high-mortality cancer with complex etiology and progression involving both genetic and environmental factors. We examined the association between esophageal cancer risk and patterns of 61 SNPs in a case-control study for a population from Shanxi Province in North Central China that has among the highest rates of esophageal squamous cell carcinoma in the world. METHODS: High-throughput Masscode mass spectrometry genotyping was done on genomic DNA from 574 individuals (394 cases and 180 age-frequency matched controls). SNPs were chosen from among genes involving DNA repair enzymes, and Phase I and Phase II enzymes. We developed a novel adaptation of the Decision Forest pattern recognition method named Decision Forest for SNPs (DF-SNPs). The method was designated to analyze the SNP data. RESULTS: The classifier in separating the cases from the controls developed with DF-SNPs gave concordance, sensitivity and specificity, of 94.7%, 99.0% and 85.1%, respectively; suggesting its usefulness for hypothesizing what SNPs or combinations of SNPs could be involved in susceptibility to esophageal cancer. Importantly, the DF-SNPs algorithm incorporated a randomization test for assessing the relevance (or importance) of individual SNPs, SNP types (Homozygous common, heterozygous and homozygous variant) and patterns of SNP types (SNP patterns) that differentiate cases from controls. For example, we found that the different genotypes of SNP GADD45B E1122 are all associated with cancer risk. CONCLUSION: The DF-SNPs method can be used to differentiate esophageal squamous cell carcinoma cases from controls based on individual SNPs, SNP types and SNP patterns. The method could be useful to identify potential biomarkers from the SNP data and complement existing methods for genotype analyses

Polymorphisms of XRCC1 genes and risk of nasopharyngeal carcinoma in the Cantonese population

BACKGROUND: Nasopharyngeal carcinoma (NPC) is one of the most common cancers in southern China. In addition to environmental factors such as Epstein-Barr virus infection and diet, genetic susceptibility has been reported to play a key role in the development of this disease. The x-ray repair cross-complementing group 1 (XRCC1) gene is important in DNA base excision repair. We hypothesized that two common single nucleotide polymorphisms of XRCC1 (codons 194 Arg→Trp and 399 Arg→Gln) are related to the risk of NPC and interact with tobacco smoking. METHODS: We sought to determine whether these genetic variants of the XRCC1 gene were associated with the risk of NPC among the Cantonese population in a hospital-based case control study using polymerase chain reaction-restriction fragment length polymorphism analysis. We conducted this study in 462 NPC patients and 511 healthy controls. RESULTS: After adjustment for sex and age, we found a reduced risk of developing NPC in individuals with the Trp194Trp genotype (OR = 0.48; 95% CI, 0.27–0.86) and the Arg194Trp genotype (OR = 0.79; 95% CI, 0.60–1.05) compared with those with the Arg194Arg genotype. Compared with those with the Arg399Arg genotype, the risk for NPC was not significantly different in individuals with the Arg399Gln genotype (OR = 0.82; 95% CI, 0.62–1.08) and the Gln399Gln genotype (OR = 1.20; 95% CI, 0.69–2.06). Further analyses stratified by gender and smoking status revealed a significantly reduced risk of NPC among males (OR = 0.32; 95% CI, 0.14–0.70) and smokers (OR = 0.34; 95% CI, 0.14–0.82) carrying the XRCC1 194Trp/Trp genotype compared with those carrying the Arg/Arg genotype. No association was observed between Arg399Gln variant genotypes and the risk of NPC combined with smoking and gender. CONCLUSION: Our findings suggest that the XRCC1 Trp194Trp variant genotype is associated with a reduced risk of developing NPC in Cantonese population, particularly in males and smokers. Larger studies are needed to confirm our findings and unravel the underlying mechanisms

Awareness of cancer symptoms and anticipated help seeking among ethnic minority groups in England

<p>Objective: Little is known about ethnic differences in awareness of cancer-warning signs or help-seeking behaviour in Britain. As part of the National Awareness and Early Diagnosis Initiative (NAEDI), this study aimed to explore these factors as possible contributors to delay in cancer diagnosis.</p> <p>Methods: We used quota sampling to recruit 1500 men and women from the six largest minority ethnic groups in England (Indian, Pakistani, Bangladeshi, Caribbean, African and Chinese). In face-to-face interviews, participants completed the newly developed cancer awareness measure (CAM), which includes questions about warning signs for cancer, speed of consultation for possible cancer symptoms and barriers to help seeking.</p> <p>Results: Awareness of warning signs was low across all ethnic groups, especially using the open-ended (recall) question format, with lowest awareness in the African group. Women identified more emotional barriers and men more practical barriers to help seeking, with considerable ethnic variation. Anticipated delay in help seeking was higher in individuals who identified fewer warning signs and more barriers.</p> <p>Conclusions: The study suggests the need for culturally sensitive, community-based interventions to raise awareness and encourage early presentation.</p&gt