Audiological and vestibular features in affected subjects with USH3: a genotype/phenotype correlation

The aims were to compare the genotype/phenotype relationship between USH3 mutations and the consequent hearing and vestibular phenotype; and to compare hearing loss (HL) progression between Usher syndrome types IB, IIA and USH3. Genetic, audiometric and vestibular examinations were performed in 28 subjects with USH3. Five different mutations in USH3 were identified. Severe HL was present from an early age (4 to 6 years) in 35% of subjects with USH3. Progression of HL begins in the first decade, and approximately 50% of subjects with USH3 become profoundly deaf by age 40. Various vestibular abnormalities were found in about half (10/22) of the tested subjects with USH3. Depending on the severity of HL, subjects with USH3 might be misdiagnosed as either Usher type IB or IIA. The results from this study can be used as discriminatory features in differential diagnosis of this syndrome.     

Why do studies show different associations between intrauterine exposure to maternal smoking and age at menarche?

Purpose

Studies suggests that intrauterine exposure to maternal smoking both accelerates or delays age at menarche. We hypothesize that these opposing findings relate to different infant and childhood growth patterns across cohorts.

Founder effect in spinal and bulbar muscular atrophy (SBMA)

We analyzed the polymorphic (CAG)n and (GGC)n repeats of the androgen receptor gene in 113 unrelated X-linked spinal and bulbar muscular atrophy (SBMA) X chromosomes and 173 control X chromosomes in Japanese males. The control chromosomes had an average CAG repeat number of 21 +/- 3 with a range from 14-32 repeat units, and SBMA chromosomes had a range from 40-55 with a median of 47 +/- 3 copies. The control chromosomes had seven different alleles of the (GGC)n repeat with the range of 11 to 17; the most frequent size of (GGC)n was 16 (79%), while (GGC)17 was very rare (1%). However, in SBMA chromosomes only two alleles were seen; the most frequent size of (GGC)n was 16 (61%) followed by 17 (39%). (GGC)n size distribution was significantly different between SBMA and control chromosomes (P < 0.0001), indicating the presence of linkage disequilibrium. There was no allelic association between the (CAG)n and (GGC)n microsatellites among control subjects as well as SBMA patients, which suggests that a founder effect makes a more significant contribution to generation of Japanese SBMA chromosomes than new mutations.      

Self-selecting albino rats exhibit differential preferences for pure macronutrient diets: Characterization of three subpopulations

Analyses of natural feeding behavior in albino male Sprague-Dawley rats demonstrate that, when allowed to self-select from pure macronutrient diets (protein, carbohydrate and fat), these rats of the same genetic strain can be categorized into 3 subpopulations according to either their 24-h or their 12-h nocturnal patterns of nutrient intake. A majority of the animals (HC for high carbohydrate, 50% of the total population) consumed a diet rich in carbohydrate relative to protein or fat, while a smaller population of rats (HF, 30%) preferred the fat diet, and an even smaller population (HP, 20%) chose a high-protein diet. These 3 subpopulations, after a few weeks of maintenance on the diets, differed in their body weight, with the HF rats having a higher body weight than the HP animals, who tended to weigh more than the lightest HC rats. Whereas all subgroups exhibited a similar bimodal distribution of feeding during the nocturnal cycle, with peaks during the early and late dark periods, they were distinguishable on the basis of their nutrient consumption during specific phases of the dark cycle. This difference was most apparent in the early dark phase, when the 3 subgroups exhibited exaggerated preferences for the specific nutrient that was generally preferred over the 24-h cycle. This is in contrast to the middle dark phase, when diet preferences were attenuated or lost, and the late dark phase, when most rats were similar in showing an increased preference for protein and fat and a decreased preference for carbohydrate. The HF group was further distinguished by an unusually strong burst of feeding during the first 2 h of the dark period and an extra peak of feeding in the middle dark period (7th h), both of which were relatively high in fat content.     

Effect of chemotherapy delays and dose reductions on progression free and overall survival in the treatment of epithelial ovarian cancer

Introduction

Hematologic, gastrointestinal, and neurologic complications are common side effects of the platinum and taxane-based chemotherapy used in the primary treatment of epithelial ovarian cancer (EOC). These side effects and the impact of the resultant chemotherapy dose modification on disease free interval have not been extensively studied. The goal of this study was to determine the effect of chemotherapy delays and dose reductions on progression free survival (PFS) and overall survival (OS).

Methods

A review of patients with primary epithelial ovarian, peritoneal, and fallopian tube carcinoma treated between 1/2000 and 12/2007 was performed. Inclusion criteria were advanced stage disease and first line chemotherapy with a platinum and taxane regimen. Cox proportional hazard models were used to determine the effect of chemotherapy reductions and delays on PFS and OS.

Results

One hundred and fifty seven patients met the inclusion criteria. Patients were divided into four groups: no delays or reductions (48%), delay only (27%), reduction only (8%), and both delay and reduction (18%). The mean number of delays/reductions per patient was 1.1 (range = 0-5) and therapy was delayed a mean of 8 days. The most common reasons for delays/reductions were neutropenia (n = 51), thrombocytopenia (n = 45), and neuropathy (n = 18). There were no differences detected in PFS or OS between groups.

Conclusions

There were no differences detected in survival between patients who required dose adjustments and treatment delays and those who did not. The lack of association between survival and chemotherapy alterations suggests that in specific circumstances patients with advanced ovarian cancer should have individualized treatment plans.     

Compositional and structural analysis of PELA biodegradable block copolymers degrading under in vitro conditions

This paper describes an investigation of the in vitro degradation of some polyethylene oxide/polylactic acid block copolymers. It has been found that the faster the degradation, the more basic the incubation medium and, as expected, the higher the temperature. The addition of enzyme proved to have no effect. This study shows that some polyethylene oxide/polylactic acid copolymers exhibit a steady increase in polylactic acid content, as degradation proceeds. This behaviour was attributed to the solubilization effect of the hydrophilic polyethylene oxide chains on the extraction of polyethylene oxide/polylactic acid-degrading fragments. Our findings indicate that polylactic acid blocks are cleaved randomly, the lactoyl end unit playing no special role. In accordance with data published for other biodegradable polymers, the crystallinity of polyethylene oxide/polylactic acid increases as degradation proceeds.     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.