Use of monofilament sutures and triclosan coating to protect against surgical site infections in spinal surgery: a laboratory-based study.

PURPOSE: We investigated bacterial propagation through multifilament, monofilament sutures and whether sutures coated with triclosan would exhibit a different phenomenon. METHODS: One centimetre (cm) wide trenches were cut in the middle of Columbia blood Agar plates. We tested a 6 cm length of two Triclosan-coated (PDS plus®, Vicryl plus®) and two uncoated (PDS ®, Vicryl ®) sutures. Each suture was inoculated with a bacterial suspension containing methicillin-sensitive Staphylococcus aureus (MSSA), Escherichia coli (E. coli), Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus (MRSA) at one end of each suture. The plates were incubated at 36C for 48 h, followed by room temperature for a further 5 days. We established bacterial propagation by observing for any bacterial growth on the Agar on the opposite side of the trench. RESULTS: Bacterial propagation was observed on the opposite side of the trench with both suture types, monofilament PDS and multifilament Vicryl, when tested with the motile bacterium (E. coli). Propagation was not observed on the other side of the trench with the monofilament PDS suture following incubation with MSSA and S. epidermidis, and in 66% of MRSA. With multifilament suture Vicryl, propagation was observed on the other side of the trench in 90% (MSSA), 80% (S. epidermidis), and 100% (MRSA) of plates tested. No bacterial propagation was observed in any of the triclosan-coated sutures (monofilament or multifilament). CONCLUSIONS: Monofilament sutures are associated in vitro with less bacterial propagation along their course when compared to multifilament sutures. Inhibition in both sutures can be further enhanced with a triclosan coating.

Who moves in vulnerable Caribbean neighborhoods? Positive deviance for physical activity: Findings from the Jamaica health and Lifestyle Survey 2017 (JHLS III).

Decreased physical activity (PA) has been associated with residents living in neighborhoods perceived as being disordered or having high crime levels. What is unknown are the characteristics of individuals who engage in moderate to vigorous levels of PA (MVPA) despite living in these vulnerable neighborhoods, or who may be referred to as positive deviants (PD). We examined the factors associated with PD for PA among Jamaicans. Between 2016 and 2017 the Jamaica Health and Lifestyle Survey, a cross-sectional nationally representative survey (n = 2807), was conducted on individuals aged 15 years and older. Regression analyses were performed to identify associations with PD, defined using engagement in MVPA among persons living in vulnerable neighborhoods (N = 1710). Being female (odds ratio [OR]a = 0.64 (0.48, 0.86); p = 0.003), obese while living in an urban area (ORa = 0.39; 95 % CI = 0.26, 0.59; p < 0.0001), unemployed (ORa = 0.53; 95 % CI = 0.39, 0.73; p < 0.0001), or a student (ORa = 0.62; 95 % CI = 0.39, 0.98); p = 0.041) was associated with a significantly lower likelihood of PD, while having a personal medical history of at least one chronic disease significantly increased likelihood (ORa = 1.43; 95 % CI = 1.08, 1.90; p = 0.014). Taking a PD approach may be one angle to consider in trying to determine what is working and for whom, so that this may be harnessed in policy, prevention and intervention programming to increase PA.

In the shadow of the dam - Hydrology of the Little Conemaugh river and its South Fork, with insights about past and future flooding.

The Little Conemaugh River watershed and its South Fork sub-basin figure prominently in historical flooding of Johnstown, Pennsylvania and nearby communities with catastrophic flooding in 1889, 1936, and 1977 (reviewed herein). Historical stream gage data and data from a new gage on the South Fork (established via a novel, portable cableway system) are used with Nexrad rainfall data to assess watershed response and provide novel analysis of flood hydrology in the Little Conemaugh basin and the sub-basin. Using unit hydrograph estimates for longer duration storms (>8 h) and different baseflow conditions, we probe possible effects of several design storms, including those stemming from a hurricane remnant scenario (Agnes in 1972) and 50-, 100-, and 500-year 12-hour precipitation depths. The unit hydrographs provided peak discharge (Qpeak) estimates for 1977 (the only flood event with available hourly rainfall data) that are in good agreement with empirical peak discharges. Significant channel improvements completed in 1943 were designed to carry the largest known natural flow on record at that time (1936 Qpeak). Preliminary results from design storm scenarios indicate the need for a careful evaluation of extreme discharges and their return periods (including snowmelt-related contributions), as future flood levels in Johnstown may occur more frequently than originally thought. The 1977 flood, which triggered 7 dam failures and eclipsed 1936 Qpeak, resulted from less than 40% the estimated probable maximum precipitation (PMP) for a 12-hour storm. Peak discharges of similar magnitude would have ensued in 1972 had remnants of Hurricane Agnes tracked slightly westward. Flooding and infrastructure problems could be compounded for storms of 24-hour or longer durations, similar to record flooding seen in central Pennsylvania and New York in 1972. Flood recurrence, emergency procedures, and dam safety (particularly, spillway capacity in the Little Conemaugh basin and surrounding region) should likely be reassessed and protective early-warning measures (ineffective in 1977) implemented for the people of Johnstown.

Beyond epidermal growth factor receptor: MET amplification as a general resistance driver to targeted therapy in oncogene-driven non-small-cell lung cancer.

The rapidly changing treatment paradigm for patients with metastatic oncogene-driven lung cancer continues to evolve, and consequently our understanding of the landscape of resistance must also advance. MET amplification is an established and frequent driver of resistance in EGFR-mutant non-small-cell lung cancer (NSCLC). Recently, the combination of MET proto-oncogene (MET) and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has shown promise in overcoming this molecularly defined resistance in clinical trials, and this combination strategy is being pursued in ongoing trials. Emerging data also demonstrate MET amplification as a resistance driver to TKI-treated ALK-, RET-, and ROS-1-fusion NSCLC, consistently at the range of 15%, while the resistance profiling data are maturing for other molecular targets. In this review, we discuss MET amplification as a driver of acquired resistance in well-defined molecular subsets of NSCLC, explore the biology behind this mechanism of resistance, and summarize the recently published clinical data, including the proposed combination strategies in the clinic achieving success in overcoming acquired MET amplification-dependent resistance.

Concurrent occurrence of a wandering spleen, organoaxial gastric volvulus, pancreatic volvulus, and cholestasis - A rare cause of an acute abdomen.

The concurrence of wandering spleen, organoaxial gastric volvulus, and pancreatic volvulus is very rare. They have been associated with symptoms such as severe abdominal pain, abdominal distention, and vomiting. However, the diagnosis remains complicated and any delay can result in ischemia and necrosis of the organs involved. In this case presentation, we present a unique case involving a 14-year-old girl who presented initially with acute abdominal pain. Assessment with enhanced computed tomography scan led to the diagnosis of wandering spleen, organoaxial gastric volvulus, and pancreatic volvulus, in addition to cholestasis, making it the first study to report on the simultaneous occurrence of this triad and cholestasis.

Sachet water quality and product registration: a cross-sectional study in Accra, Ghana.

The study's objectives were to assess the extent to which packaged water producers follow product registration procedures and to assess the relationship between product registration and drinking water quality in Accra, Ghana. Following preliminary analysis of a national water quality survey, 118 packaged sachet water samples were collected by sampling all brands sold by 66 vendors. A sample of vendors was selected from two high-income and two low-income areas of Accra, Ghana. Sachet packaging and labelling details were recorded and compared to a regulatory database to assess product registration. All samples were weighed and tested for faecal indicator bacteria and selected physico-chemical parameters. Product registration numbers and brand names could be matched to regulatory records for 77 of 118 sachets (65.2%). All samples tested were compliant with national water quality standards for faecal indicator bacteria and nitrate. Brand registration was not associated with any of the quality indicators considered. The results of this study suggest that while a substantial proportion of sachet water is sold without formal product registration, the microbial quality of the unlicensed water is consistently high in Accra, Ghana. Further examination of regulatory enforcement and monitoring will be needed to ensure sustained high water quality over time.

Parish Prevalence Estimates of Obesity, Diabetes and Hypertension in Jamaica: Is It Now Time for More Targeted Public Health Interventions? / Estimados de la Prevalencia de la Obesidad, la Diabetes y la Hipertensión por Parroquia en Jamaica: ¿Es ya Tiempo de Realizar Intervenciones de Salud Pública Más Específicas?

ABSTRACT Objective: Geographic variation in obesity, Diabetes mellitus (DM) and hypertension (HTN) prevalence at the parish level was examined using the Jamaica Health and Lifestyle Survey 2008 (JHLS II). Methods: Total and sex-specific parish age-adjusted prevalence estimates of obesity, DM and HTN were obtained and ranked. Binary logistic regression models were adjusted for age, urbanicity, educational level, physical activity and diet. Results: Parish prevalence ranges were obesity 19.5-37.8% (1.7-31.0% in men versus 27.39-48.30% in women); DM 5.08-37.82% (0-26.45% in men versus 7.11-14.17% in women) and HTN 19.50-36.02% (10.94-48.39% in men versus 18.85-36.61% in women). The highest parish prevalences were St Elizabeth for obesity, Portland for DM and St Mary for HTN. Men residing in St Elizabeth were 16 times more obese compared to those in Portland [(Odds Ratio) OR = 15.84; 95% CI = 2.00, 125.51, p < 0.01], while women in St Elizabeth had twice the odds of being obese compared to those in St Ann [OR = 2.3; 95% CI, 1.007, 5.3). Men in Portland were eight times more likely to have HTN compared to those residing in St Ann (OR = 7.70; 95% CI = 2.34, 25.40, p = 0.001) whilst women in St Mary were three times more likely to be hypertensive compared to those living in St Thomas (OR = 3.05; 95% CI = 1.63, 5.72, p = 0.001). No significant associations were seen with DM. Conclusion: Significant heterogeneity exists at the parish level in obesity, DM and HTN, with important sex differences. Further analyses are needed to understand the determinants and work toward context-specific prevention and intervention programming.

RESUMEN Objetivo: La variación geográfica de la prevalencia de la obesidad, la diabetes mellitus (DM) y la hipertensión (HT) a nivel parroquia, se examinó usando la Encuesta 2008 sobre Salud y Estilo de Vida de Jamaica (JHLS-2). Métodos: Los estimados totales y específicos por género, ajustados por edad y a nivel de parroquia, de la prevalencia de la obesidad, DM y HT, fueron obtenidos y clasificados. Los modelos de regresión logística binaria fueron ajustados por edad, urbanidad, nivel educacional, actividad física, y dieta. Resultados: Los rangos de prevalencia por parroquia fueron como sigue: obesidad 19.5- 37.8% (1.7-31.0% en hombres versus 27.39-48.30% en mujeres); DM 5.08-37.82% (0- 26.45% en hombres versus 7.11-14.17% en mujeres); y HT 19.50-36.02% (10.94-48.39% en hombres versus 18.85-36.61% en mujeres). Las prevalencias más altas por parroquia fueron: Saint Elizabeth en obesidad, Portland en DM, y Saint Mary en HT. Los hombres de Saint Elizabeth eran 16 veces más obesos en comparación con los de Portland [(Odds Ratio) OR = 15.84; 95% IC = 2.00, 125.51, p < 0.01], mientras que las mujeres de Saint Elizabeth tenían el doble de probabilidades de ser obesas en comparación con las de Saint Ann (OR = 2.3; 95% IC, 1.007, 5.3). Los hombres de Portland eran ocho veces más propensos a padecer de HT en comparación con los residentes en Saint Ann (OR = 7.70; 95% IC = 2.34, 25.40, p = 0.001) en tanto que las mujeres de Saint Mary tenían tres veces más probabilidades de ser hipertensas comparadas con las que viven en Saint Thomas (OR = 3.05; 95% IC = 1.63, 5.72, p = 0.001). No se observaron asociaciones significativas con DM. Conclusión: Existe una heterogeneidad significativa a nivel de parroquias en cuanto a obesidad, DM, y HT, con importantes diferencias de género. Se necesitan más análisis para entender las determinantes y trabajar hacia la programación de intervenciones y prevenciones específicas del contexto.

The impact of Er:YAG laser enamel conditioning on the microleakage of a new hydrophilic sealant--UltraSeal XT hydro.

UltraSeal XT hydro is a new hydrophilic, light-cured, methacrylate-based pit and fissure sealant which has been developed by Ultradent Products, USA. The sealant is highly filled with a 53 wt.% mixture of inorganic particles which confer both thixotropy and radiopacity. The principal purpose of this study was to investigate the microleakage of UltraSeal XT hydro as a function of different enamel etching techniques. The occlusal surfaces of sound, extracted human molars were either acid etched, Er:YAG laser irradiated or successively laser irradiated and acid etched. UltraSeal XT hydro was applied to each group of teeth (n = 10) which were subjected to a thermocycling process consisting of 2500 cycles between 5 and 50 °C with a dwell time of 30 s. Microleakage assessments were then carried out using 0.5% fuchsin dye and optical microscopy. The microleakage score data were analysed using the Kruskal-Wallis, Mann-Whitney U test with Bonferroni adjustment. No significant differences in microleakage were noted between the individually acid etched and laser-irradiated groups (p > 0.05); however, teeth treated with a combination of laser irradiation and acid etching demonstrated significantly lower microleakage scores (p < 0.001). Electron microscopy with energy-dispersive X-ray analysis revealed that the mineral filler component of UltraSeal XT hydro essentially comprises micrometre-sized particles of inorganic silicon-, aluminium- and barium-bearing phases. Laser etching increases the roughness of the enamel surface which causes a concentrated zoning of the filler particles at the enamel-sealant interface.

HPV16 oncogene expression levels during early cervical carcinogenesis are determined by the balance of epigenetic chromatin modifications at the integrated virus genome.

In cervical squamous cell carcinomas, high-risk human papillomavirus (HRHPV) DNA is usually integrated into host chromosomes. Multiple integration events are thought to be present within the cells of a polyclonal premalignant lesion and the features that underpin clonal selection of one particular integrant remain poorly understood. We previously used the W12 model system to generate a panel of cervical keratinocyte clones, derived from cells of a low-grade premalignant lesion naturally infected with the major HRHPV type, HPV16. The cells were isolated regardless of their selective advantage and differed only by the site of HPV16 integration into the host genome. We used this resource to test the hypothesis that levels of HPV16 E6/E7 oncogene expression in premalignant cells are regulated epigenetically. We performed a comprehensive analysis of the epigenetic landscape of the integrated HPV16 DNA in selected clones, in which levels of virus oncogene expression per DNA template varied ~6.6-fold. Across the cells examined, higher levels of virus expression per template were associated with more open chromatin at the HPV16 long control region, together with greater loading of chromatin remodelling enzymes and lower nucleosome occupancy. There were higher levels of histone post-translational modification hallmarks of transcriptionally active chromatin and lower levels of repressive hallmarks. There was greater abundance of the active/elongating form of the RNA polymerase-II enzyme (RNAPII-Ser2P), together with CDK9, the component of positive transcription elongation factor b complex responsible for Ser2 phosphorylation. The changes observed were functionally significant, as cells with higher HPV16 expression per template showed greater sensitivity to depletion and/or inhibition of histone acetyltransferases and CDK9 and less sensitivity to histone deacetylase inhibition. We conclude that virus gene expression per template following HPV16 integration is determined through multiple layers of epigenetic regulation, which are likely to contribute to selection of individual cells during cervical carcinogenesis.

Prevalence of Chronic Kidney Disease among Patients Attending a Specialist Diabetes Clinic in Jamaica.

OBJECTIVE: To estimate the prevalence of chronic kidney disease (CKD) among patients attending the University Hospital of the West Indies (UHWI) Diabetes Clinic and to determine the proportion of patients at high risk for adverse outcomes. METHODS: We conducted a cross-sectional study among patients attending the UHWI Diabetes Clinic between 2009 and 2010. Trained nurses administered a questionnaire, reviewed dockets, and performed urinalyses. Estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Albuminuria was assessed using urine test strips for protein and microalbumin. Chronic kidney disease was defined as an eGFR < 60 ml/min/1.73m2 or albuminuria ≥ 30 mg/g creatinine. Risk of adverse outcome (all-cause mortality, cardiovascular disease and kidney failure) was determined using the Kidney Disease: Improving Global Outcome (KDIGO) 2012 prognosis grid. RESULTS: Participants included 100 women and 32 men (mean age, 55.4 ± 12.9 years, mean duration of diabetes, 16.7 ± 11.7 years). Twenty-two per cent of participants had eGFR < 60 ml/min/1.73m2. Moderate albuminuria (30-300 mg/g) was present in 20.5% of participants and severe albuminuria (> 300 mg/g) in 62.1%. Overall prevalence of CKD was 86.3% (95%CI 80.4%, 92.2%). Based on KDIGO risk categories, 50.8% were at high risk and 17.4% at very high risk of adverse outcomes. CONCLUSION: Most patients at the UHWI Diabetes Clinic had CKD and were at high or very high risk of adverse outcomes. Further studies to determine the burden of CKD in other clinical settings and to identify the best strategies for preventing adverse outcomes in developing countries need to be conducted.

Biology of childhood germ cell tumours, focussing on the significance of microRNAs.

Genomic and protein-coding transcriptomic data have suggested that germ cell tumours (GCTs) of childhood are biologically distinct from those of adulthood. Global messenger RNA profiles segregate malignant GCTs primarily by histology, but then also by age, with numerous transcripts showing age-related differential expression. Such differences are likely to account for the heterogeneous clinico-pathological behaviour of paediatric and adult malignant GCTs. In contrast, as global microRNA signatures of human tumours reflect their developmental lineage, we hypothesized that microRNA profiles would identify common biological abnormalities in all malignant GCTs owing to their presumed shared origin from primordial germ cells. MicroRNAs are short, non-protein-coding RNAs that regulate gene expression via translational repression and/or mRNA degradation. We showed that all malignant GCTs over-express the miR-371-373 and miR-302/367 clusters, regardless of patient age, histological subtype or anatomical tumour site. Furthermore, bioinformatic approaches and subsequent Gene Ontology analysis revealed that these two over-expressed microRNAs clusters co-ordinately down-regulated genes involved in biologically significant pathways in malignant GCTs. The translational potential of this finding has been demonstrated with the detection of elevated serum levels of miR-371-373 and miR-302/367 microRNAs at the time of malignant GCT diagnosis, with levels falling after treatment. The tumour-suppressor let-7 microRNA family has also been shown to be universally down-regulated in malignant GCTs, because of abundant expression of the regulatory gene LIN28. Low let-7 levels resulted in up-regulation of oncogenes including MYCN, AURKB and LIN28 itself, the latter through a direct feedback mechanism. Targeting LIN28, or restoring let-7 levels, both led to effective inhibition of this pathway. In summary, paediatric malignant GCTs show biological differences from their adult counterparts at a genomic and protein-coding transcriptome level, whereas they both display very similar microRNA expression profiles. These similarities and differences may be exploited for diagnostic and/or therapeutic purposes.

Serum levels of mature microRNAs in DICER1-mutated pleuropulmonary blastoma.

DICER1 is a critical gene in the biogenesis of mature microRNAs, short non-coding RNAs that derive from either -3p or -5p precursor microRNA strands. Germline mutations of DICER1 are associated with a range of human malignancies, including pleuropulmonary blastoma (PPB). Additional somatic 'hotspot' mutations in the microRNA processing ribonuclease IIIb (RNase IIIb) domain of DICER1 are reported in cancer, and which affect microRNA biogenesis, resulting in a -3p mature microRNA strand bias. Here, in a germline (exon11 c.1806_1810insATTGA) DICER1-mutated PPB, we first confirmed the presence of an additional somatic RNase IIIb hotspot mutation (exon25 c.5425G>A [p.G1809R]) by conventional sequencing. Second, we investigated serum levels of mature microRNAs at the time of PPB diagnosis, and compared the findings with serum results from a comprehensive range of pediatric cancer patients and controls (n=52). We identified a panel of 45 microRNAs that were present at elevated levels in the serum at the time of PPB diagnosis, with a significant majority noted be derived from the -3p strand (P=0.013). In addition, we identified a subset of 10 serum microRNAs (namely miR-125a-3p, miR-125b-2-3p, miR-380-5p, miR-125b-1-3p, let-7f-2-3p, let-7a-3p, let-7b-3p, miR-708-3p, miR-138-1-3p and miR-532-3p) that were most abundant in the PPB case. Serum levels of two representative microRNAs, miR-125a-3p and miR-125b-2-3p, were not elevated in DICER1 germline-mutated relatives. In the PPB case, serum levels of miR-125a-3p and miR-125b-2-3p increased before chemotherapy, and then showed an early reduction following treatment. These microRNAs may offer future utility as serum biomarkers for screening patients with known germline DICER1 mutations for early detection of PPB, and for potential disease-monitoring in cases with confirmed PPB.

Ischaemic Heart Disease at the University Hospital of the West Indies: Trends in Hospital Admissions and Inpatient Mortality Rates 2005-2010.

OBJECTIVES: This study aimed to estimate hospital admission rates and inpatient mortality rates for ischaemic heart disease (IHD) and its subtypes at the University Hospital of the West Indies (UHWI) for the years 2005─2010, and to identify factors associated with inpatient mortality. METHODS: Data from electronic discharge summaries for patients diagnosed with acute myocardial infarction (A-MI), unstable angina (UA) or other IHD were obtained from the Patient Information Management Systems database of the Medical Records Department of the UHWI. Data were entered into an electronic database and analysed using Stata 10.1. Random effects logistic regression was used to identify factors associated with inpatient mortality. RESULTS: Analysis included 3794 admissions (2821 persons: 1415 males, 1406 females; mean age 63.9 ± 13.5 years). Overall admission rates for IHD were 12.1% (95% CI 11.7, 12.5) for medical admissions and 4.02% (95% CI 3.89, 4.15) for non-paediatric admissions. Admission rates were higher among males compared to females. There was a statistically significant trend for an overall increase in the rates for IHD admissions over the study period. Inpatient mortality rate was 18.9% for A-MI, 1.6% for UA and 7.8% for other IHD. In multivariable models, adjusted for age and gender, A-MI was associated with higher mortality compared to other IHD (OR 3.38, p < 0.001). CONCLUSIONS: Ischaemic heart disease admission rate is increasing at the UHWI and accounts for approximately one of every eight medical admissions. Inpatient mortality for acute myocardial infarction is approximately 19%. Further studies are required to determine the factors associated with inpatient mortality and to inform strategies for improving outcomes.

Bioactivity and biocompatibility of a chitosan-tobermorite composite membrane for guided tissue regeneration.

A polymer-mineral composite membrane of the mucopolysaccharide derivative, chitosan, and calcium silicate hydrate phase, tobermorite, was prepared by solvent casting and characterised by scanning electron microscopy (SEM) and Fourier Transform infrared spectroscopy (FTIR). The bioactivity and biocompatibility of the chitosan-tobermorite composite were evaluated in vitro with respect to its potential for use as a biodegradable guided tissue regeneration (GTR) membrane. The in vitro bioactivity of the composite was confirmed by the formation of crystalline substituted hydroxyapatite on the surface of the embedded tobermorite particles in simulated body fluid. The presence of the composite membrane was found to enhance the growth of MG63 human osteosarcoma cells by up to 30%. The findings of this initial study have indicated that this novel chitosan-tobermorite composite may be a suitable material for GTR applications.

A paucity of liver disease in Canadian Inuit with chronic hepatitis B virus, subgenotype B6 infection.

Clinical observations suggest that chronic hepatitis B virus (HBV) infections in the Canadian Inuit are less often associated with serious adverse outcomes than has been described in other HBV-infected patient populations. The aim of this study was to document the clinical and biochemical features, liver-related morbidity and all-cause mortality in Canadian Inuit with chronic HBV infections. Administrative databases were reviewed for individuals identified as hepatitis B surface antigen (HBsAg) positive during a 1983-85 seroepidemiological survey of viral hepatitis in Baffin Island, Canada. An equal number of age- and gender-matched HBsAg-negative individuals from the same communities served as controls. Baseline HBV viral loads, genotypes and specific mutations were compared in HBsAg-positive survivors and nonsurvivors. A subset of surviving HBsAg-positive carriers were reassessed 25-30 years following their initial diagnosis for evidence of advanced liver disease and changes to their serological/virological findings. One hundred and forty four HBsAg-positive individuals were identified. All were Canadian Inuit. The mean age at diagnosis was 38 ± 17 years and 69 (61%) were male. Median follow-up was 23 years (range: 2-28 years). Viral quantitation from stored sera could be performed in 70 infected individuals. The median viral load was 4.3 log 10 IU/ml (range: 2.3-8.8 log 10 IU/ml), and all were genotype B, subgenotype B6. Liver biochemistry, morbidity and all-cause mortality rates were similar in HBsAg-positive carriers and controls. Following multivariate analyses, only age at diagnosis predicted mortality in HBsAg carriers. In a subset of 30 HBsAg-positive survivors who underwent follow-up assessments, clinical, biochemical and radiological examinations of the liver were essentially normal. 23/30 (77%) remained HBsAg positive and 17/19 (90%) HBV-DNA positive. The genotype and prevalence of genomic mutations in this cohort remained largely unchanged, but quantifiable viral loads were significantly lower (P < 0.003). The results of this study suggest that chronic HBV infections in the Canadian Inuit are infrequently associated with serious adverse outcomes. Whether this finding reflects unique features of the host, presence or absence of external factors that influence the course of HBV and/or intrinsic properties of the HBV B6 subgenotype remains to be determined.

DICER1 hotspot mutations in non-epithelial gonadal tumours.

BACKGROUND: Non-epithelial gonadal tumours largely comprise sex cord-stromal tumours (SCSTs) and germ cell tumours (GCTs). Specific somatic mutations in DICER1, a microRNA maturation pathway gene, have been identified in these tumours. We conducted a study that aimed to confirm, refine and extend the previous observations. METHODS: We used Sanger sequencing to sequence the RNase IIIa and IIIb domains of DICER1 in 154 gonadal tumours from 135 females and 19 males, as well as 43 extra-gonadal GCTs from 26 females and 17 males. RESULTS: We identified heterozygous non-synonymous mutations in the RNase IIIb domain of DICER1 in 14/197 non-epithelial tumours (7.1%). Mutations were found in 9/28 SCSTs (32%), 5/118 gonadal GCTs (4.2%), 0/43 extra-gonadal GCTs and 0/8 miscellaneous tumours. The 14 mutations affected only five residues: E1705, D1709, E1788, D1810 and E1813. In all five patients where matched and constitutional DNA was available, the mutations were only somatic. There were no mutations found in the RNase IIIa domain. CONCLUSION: More than half (8/15) of Sertoli-Leydig cell tumours (SLCTs) harbour DICER1 mutations in the RNase IIIb domain, while mutations are rarely found in GCTs. Genetic alterations in SLCTs may aid in classification and provide new approaches to therapy.

Lack of correlation between predicted and actual off-target effects of short-interfering RNAs targeting the human papillomavirus type 16 E7 oncogene.

BACKGROUND: When designing therapeutic short-interfering RNAs (siRNAs), off-target effects (OTEs) are usually predicted by computational quantification of messenger RNAs (mRNAs) that contain matches to the siRNA seed sequence in their 3' UTRs. It is assumed that the higher the number of predicted transcriptional OTEs, the greater the size of the actual OTE signature and the more detrimental the phenotypic consequences in target-negative cells. METHODS: We tested this general assumption by investigating the OTEs of potential therapeutic siRNAs targeting the human papillomavirus (HPV) type-16 E7 oncogene. We studied HPV-negative squamous epithelial cells, from normal cervix (NCx) and skin (HaCaT), which would be vulnerable to 'bystander' OTEs following transfection in vivo. RESULTS: We observed no correlation between the number of computationally predicted OTEs and the actual number of seed-dependent OTEs (P=0.76). On average only 20.5% of actual transcriptional OTEs were seed-dependent (i.e., predicted). The unpredicted OTEs included stimulation of innate immune pathways, as well as indirect (downstream) effects of other OTEs, which affected important cancer-associated pathways. Although most significant OTEs observed were seen in both NCx and HaCaT cells, only 0-5.9% of differentially expressed genes overlapped between the two cell types. CONCLUSION: These data do not support the assumption that actual OTEs correlate well with predicted OTEs.