Chromosomal Evolution in Aspredinidae (Teleostei, Siluriformes): Insights on Intra- and Interspecific Relationships with Related Groups.

The family Aspredinidae comprises a clade of complex systematic relationships, both from molecular and morphological approaches. In this study, conventional and molecular cytogenetic studies coupled with nucleotide sequencing were performed in 6 Aspredininae species (Amaralia hypsiura, Bunocephalus cf. aloikae, Bunocephalus amaurus, Bunocephalus aff. coracoideus, Bunocephalus verrucosus, and Platystacus cotylephorus) from different locations of the Amazon hydrographic basin. Our results showed highly divergent diploid numbers (2n) among the species, ranging from 49 to 74, including the occurrence of an XX/X0 sex chromosome system. A neighbor-joining phylogram based on the cytochrome c oxidase I (COI) showed that Bunocephalus coracoideus is not a monophyletic clade, but closely related to B. verrucosus. The karyotypic data associated with COI suggest an ancestral karyotype for Aspredinidae with a reduced 2n, composed of bi-armed chromosomes and a trend toward chromosomal fissions resulting in higher diploid number karyotypes, mainly composed of acrocentric chromosomes. Evolutionary relationships were discussed under a phylogenetic context with related species from different Siluriformes families. The karyotype features and chromosomal diversity of Aspredinidae show an amazing differentiation, making this family a remarkable model for investigating the evolutionary dynamics in siluriforms as well as in fish as a whole.

OXYTOCIN REDUCES SEIZURE BURDEN AND HIPPOCAMPAL INJURY IN A RAT MODEL OF PERINATAL ASPHYXIA.

CONTEXT: Foetal asphyxia, a frequent birth complication, detrimentally impacts the immature brain, resulting in neuronal damage, uncontrolled seizure activity and long-term neurological deficits. Oxytocin, a neurohormone mediating important materno-foetal interactions and parturition, has been previously suggested to modulate the immature brain's excitability, playing a neuroprotective role. Our aim was to investigate the effects of exogenous oxytocin administration on seizure burden and acute brain injury in a perinatal model of asphyxia in rats. ANIMALS AND METHODS: Asphyxia was modelled by exposing immature rats to a 90-minute episode of low oxygen (9% O2) and high CO2 (20% CO2). Control rats were kept in ambient room-air for the same time interval. In a third group of experiments, oxytocin (0.02 UI/g body weight) was nasally administered 30 minutes before the asphyxia episode. Seizure burden was assessed by the cumulative number of loss of righting reflex (LRR) over a two-hour postexposure period. Acute brain injury was assessed through hippocampal S-100 beta, a biomarker of cellular injury, 24-hours after exposure. RESULTS: Asphyxia increased both LRR and hippocampal S-100 beta protein compared to controls, and these effects were significantly reduced by oxytocin administration. CONCLUSION: Oxytocin treatment decreased both seizure burden and hippocampal injury, supporting a potential neuroprotective role for oxytocin in perinatal asphyxia.

The Bunocephalus coracoideus Species Complex (Siluriformes, Aspredinidae). Signs of a Speciation Process through Chromosomal, Genetic and Ecological Diversity.

Bunocephalus is the most species-rich Aspredinidae genus, corresponding to a monophyletic clade with 13 valid species. However, many species have their classification put in question. Here, we analyzed individuals from four Amazonian populations of Bunocephalus coracoideus by cytogenetic and molecular procedures. The geographic distribution, genetic distances and karyotype data indicate that each population represents an Evolutionary Significant Unit (ESU). Cytogenetic markers showed distinct 2n and karyotype formulas, as well as different numbers and locations of the rDNA sites among ESUs. One of such populations (ESU-D) highlighted an extensive polymorphic condition, with several cytotypes probably due to chromosomal rearrangements and meiotic non-disjunctions. This resulted in several aneuploid karyotypes, which was also supported by the mapping of telomeric sequences. Phylograms based on Maximum Likelihood (ML) and Neighbor Joining (NJ) analyses grouped each ESU on particular highly supported clades, with the estimation of evolutionary divergence indicating values being higher than 3.8-12.3% among them. Our study reveals a huge degree of chromosomal and genetic diversity in B. coracoideus and highly points to the existence of four ESUs in allopatric and sympatric speciation processes. In fact, the high divergences found among the ESUs allowed us to delimitate lineages with taxonomic uncertainties in this nominal species.

Who mixes with whom among men who have sex with men? Implications for modelling the HIV epidemic in southern India.

In India, the identity of men who have sex with men (MSM) is closely related to the role taken in anal sex (insertive, receptive or both), but little is known about sexual mixing between identity groups. Both role segregation (taking only the insertive or receptive role) and the extent of assortative (within-group) mixing are known to affect HIV epidemic size in other settings and populations. This study explores how different possible mixing scenarios, consistent with behavioural data collected in Bangalore, south India, affect both the HIV epidemic, and the impact of a targeted intervention. Deterministic models describing HIV transmission between three MSM identity groups (mostly insertive Panthis/Bisexuals, mostly receptive Kothis/Hijras and versatile Double Deckers), were parameterised with behavioural data from Bangalore. We extended previous models of MSM role segregation to allow each of the identity groups to have both insertive and receptive acts, in differing ratios, in line with field data. The models were used to explore four different mixing scenarios ranging from assortative (maximising within-group mixing) to disassortative (minimising within-group mixing). A simple model was used to obtain insights into the relationship between the degree of within-group mixing, R0 and equilibrium HIV prevalence under different mixing scenarios. A more complex, extended version of the model was used to compare the predicted HIV prevalence trends and impact of an HIV intervention when fitted to data from Bangalore. With the simple model, mixing scenarios with increased amounts of assortative (within-group) mixing tended to give rise to a higher R0 and increased the likelihood that an epidemic would occur. When the complex model was fit to HIV prevalence data, large differences in the level of assortative mixing were seen between the fits identified using different mixing scenarios, but little difference was projected in future HIV prevalence trends. An oral pre-exposure prophylaxis (PrEP) intervention was modelled, targeted at the different identity groups. For intervention strategies targeting the receptive or receptive and versatile MSM together, the overall impact was very similar for different mixing patterns. However, for PrEP scenarios targeting insertive or versatile MSM alone, the overall impact varied considerably for different mixing scenarios; more impact was achieved with greater levels of disassortative mixing.

Differences between seven measures of self-reported numbers of clients of female sex workers in southern India: implications for individual- and population-level analysis.

Quantifying sexual activity of sub-populations with high-risk sexual behaviour is important in understanding HIV epidemiology. This study examined inconsistency of seven outcomes measuring self-reported clients per month (CPM) of female sex workers (FSWs) in southern India and implications for individual/population-level analysis. Multivariate negative binomial regression was used to compare key social/environmental factors associated with each outcome. A transmission dynamics model was used to assess the impact of differences between outcomes on population-level FSW/client HIV prevalence. Outcomes based on 'clients per last working day' produced lower estimates than those based on 'clients per typical day'. Although the outcomes were strongly correlated, their averages differed by approximately two-fold (range 39.0-79.1 CPM). The CPM measure chosen did not greatly influence standard epidemiological 'risk factor' analysis. Differences across outcomes influenced HIV prevalence predictions. Due to this uncertainty, we recommend basing population-based estimates on the range of outcomes, particularly when assessing the impact of interventions.

Impact of insurance type on survivor-focused and general preventive health care utilization in adult survivors of childhood cancer: the Childhood Cancer Survivor Study (CCSS).

BACKGROUND: Lack of health insurance is a key barrier to accessing care for chronic conditions and cancer screening. The influence of insurance type (private, public, none) on survivor-focused and general preventive health care in adult survivors of childhood cancer was examined. METHODS: The Childhood Cancer Survivor Study is a retrospective cohort study of childhood cancer survivors diagnosed between 1970 and 1986. Among 8425 adult survivors, the relative risk (RR) and 95% confidence interval (CI) of receiving survivor-focused and general preventive health care were estimated for uninsured (n = 1390) and publicly insured (n = 640), compared with for the privately insured (n = 6395) RESULTS: Uninsured survivors were less likely than those privately insured to report a cancer-related visit (adjusted RR, 0.83; 95% CI, 0.75-0.91) or a cancer center visit (adjusted RR, 0.83; 95% CI, 0.71-0.98). Uninsured survivors had lower levels of utilization in all measures of care in comparison with privately insured. In contrast, publicly insured survivors were more likely to report a cancer-related visit (adjusted RR, 1.22; 95% CI, 1.11-1.35) or a cancer center visit (adjusted RR, 1.41; 95% CI, 1.18-1.70) than were privately insured survivors. Although publicly insured survivors had similar utilization of general health examinations, they were less likely to report a Papanicolaou test or a dental examinations CONCLUSIONS: Among this large, socioeconomically diverse cohort, publicly insured survivors utilize survivor-focused health care at rates at least as high as survivors with private insurance. Uninsured survivors have lower utilization of both survivor-focused and general preventive health care.

Association between receipt and timing of adjuvant chemotherapy and survival for patients with stage III colon cancer in Alberta, Canada.

BACKGROUND: Surgery followed by adjuvant chemotherapy has been standard treatment for stage III colon cancer since 1990. However, to date, clinical trials have not been conducted to determine the definitive outer time limit by which adjuvant chemotherapy should be received for optimal survival benefit. The objective of the current study was to assess the association between the receipt/timing of adjuvant chemotherapy and patient survival in clinical practice. METHODS: Residents of Alberta who were diagnosed with stage III colon adenocarcinoma in years 2000 to 2005 who underwent surgery were included in the study. Patients were identified from the Alberta Cancer Registry and were linked to hospital data and neighborhood-level socioeconomic data from the 2001 Canadian Census. Cox proportional hazards models were used to estimate hazard ratios of death according to the timing of chemotherapy. RESULTS: There were 1053 patients in the study; 648 (61%) initiated adjuvant chemotherapy within 16 weeks of surgery. There was no difference in overall survival or colon cancer-specific survival between those who received adjuvant chemotherapy from 8 to 12 weeks postsurgery compared with those who received it within 8 weeks. However, those who received chemotherapy 12 to 16 weeks after surgery and those who either received it >16 weeks after surgery or received no treatment had a 43% and 107% greater risk of dying, respectively, than those who received chemotherapy within 8 weeks of surgery (hazard ratio, 1.43 [95% confidence interval, 0.96-2.13] and hazard ratio, 2.07 [95% confidence interval, 1.56-2.76], respectively). Analyses were controlled for age, year, and region of residence at diagnosis; sex; neighborhood-level socioeconomic factors; and number of comorbidities. CONCLUSIONS: The results from this study were consistent with current guideline recommendations in Alberta that patients with stage III adenocarcinoma should receive chemotherapy within 12 weeks of surgery.

An exploratory study of body composition as a determinant of epirubicin pharmacokinetics and toxicity.

PURPOSE: Although body composition has emerged as an important predictor of drug efficacy and toxicity, explanations for this association are unclear. Our goal was to investigate relationships between lean body mass (LBM), liver size/function and epirubicin pharmacokinetics (PK) and toxicity. METHODS: Data from a clinical study (n = 24) of patients with breast cancer receiving adjuvant intravenous FE(100)C chemotherapy were used to examine relationships between LBM, liver size, and epirubicin clearance. Muscle tissue and liver mass were measured by analysis of computerized tomography cross-sectional images, and an extrapolation of muscle mass to total LBM compartment was employed. Population PK analysis of epirubicin was undertaken to test effects of body composition on epirubicin clearance and area under the curve (AUC). RESULTS: Estimated LBM was extremely variable in this cohort ranging from 32.9 to 67.3 kg. LBM was associated with neutrophil nadir (r = 0.5, P = 0.023), and mean LBM was lower for patients presenting with toxicity compared to those where toxicity was absent (41.6 vs. 56.2 kg, P = 0.002); 33% of variance in clearance was explained by LBM and aspartate aminotransferase (AST). Liver mass was not related to epirubicin clearance likely due to larger livers presenting with larger fat content, but liver attenuation (degree of fat infiltration) and AST were associated with AUC. CONCLUSION: To our knowledge, this is the first study to examine relationships between LBM, liver mass/function and epirubicin PK and toxicity. This exploratory work investigates the notion of organs and tissues having distinctive contributions to the distribution and metabolism of antineoplastic drugs.