Studies on otitis externa in dogs. I. Survey of aetiological agents: fungi

The mechanism of the teratogenic effect of thalidomide is unknown. The hypothesis that this drug acts on the sensory nerves of the embryo was derived from radiological observations of two series of thalidomide-deformed children. Supplementary evidence was found in neurological, embryological and other literature, to support the hypothesis of embryonic neuropathy. The concept can be extended to include visceral as well as skeletal deformities. Evidence for and against the hypothesis is presented, and its application to a broad spectrum of congenital deformities provides an explanation of a number of previously unrelated facts. Areas for further research are suggested.     

Emissions of chromium, copper, arsenic, and PCDDs/Fs from open burning of CCA-treated wood

Aged and weathered chromated copper arsenate (CCA) treated wood was burned in an open burn research facility to characterize the air emissions and residual ash. The objectives were to simulate, to the extent possible, the combustion of such waste wood as might occur in an open field or someone's backyard; to characterize the composition and particle size distribution (PSD) of the emitted fly ash; to determine the partitioning of arsenic, chromium, and copper between the fly ash and residual ash; and to examine the speciation of the CCA elements. This work reports preliminary air emission concentrations and estimated emission factors for total particulate matter, arsenic (As), chromium (Cr), copper (Cu), and polychlorinated dibenzodioxins/dibenzofurans (PCDD/F) totals and toxic equivalents (TEQs). The partitioning of As, Cr, and Cu between the emitted fly ash and residual ash is examined and thermochemical predictions from the literature are used to explain the observed behavior. Results indicate a unimodal fly ash PSD between 0.1 and 1.0 microm diameter. In addition to a large carbonaceous component, between 11 and 14% of the As present in the burned CCA treated wood was emitted with the air emissions, with the remainder present in the residual ash. In contrast, less than 1% of both the Cr and Cu present in the wood was emitted with the air emissions. PCDD/F levels were unremarkable, averaging 1.7 ng TEQ/kg of treated wood burned, a value typical for wood combustion. Scanning electron microscopy (SEM) was unable to resolve inorganic particles consisting of Cu, Cr, or As in the wood samples, but X-ray absorption fine structure (XAFS) spectroscopy confirmed that the oxidation states of the CCA elements in the wood were Cu2+, Cr3+, and As5+. SEM examination of the fly ash samples revealed some inorganic microcrystals within the mostly carbonaceous fly ash, while XAFS spectroscopy of the same samples showed that the oxidation states after combustion were mixed Cu+ and Cu2+, Cr3+, and mixed As3+ and As5+. Estimates of the ratios of the mixed oxidation states based on the XAFS spectra were As3+/(total As) = 0.8-0.9 and Cu+/(total Cu) = 0.65-0.7. The Cu and Cr present in the fly ash were determined to coexist predominantly in the two oxide phases CuCrO2 and CuCr2O4. These results indicate that the open burning of CCA-treated wood can lead to significant air emissions of the more toxic trivalent form of As in particle sizes that are most respirable.     

Hyperthyroidism in elderly patients

Hyperthyroid disorders occur in older people and often are present with atypical findings or as apathetic hyperthyroidism. Hyperthyroidism exacerbates underlying chronic disease, especially cardiovascular conditions. Elderly people can be treated successfully and stabilized with careful screening, astute diagnostics, and appropriate therapy.     

Lack of association between the polyadenylation polymorphism in the NAT1 (acetyltransferase 1) gene and colorectal adenomas

Smoking and a high intake of red meat are risk factors for colorectal tumors. These effects could be due to aromatic amine carcinogens. Individual susceptibility to aromatic amines has been related to acetylation phenotype, which plays a role in the bioactivation of arylamines. Polymorphisms in both N-acetyltransferase genes, NAT1 and NAT2, have been associated with an increased risk of colorectal tumors. We studied the NAT1*10 fast acetylator allele (1088 T-->A mutation) and distal adenomas in a sigmoidoscopy-based case-control study (441 cases, 484 controls). We found neither an increased adenoma prevalence in subjects homozygous or heterozygous for the NAT1*10 fast acetylator allele (odds ratio 1.04; 95% confidence interval 0.79-1.36), nor a gene-gene interaction between NA1 and NAT2 (P(interaction) = 0.59). Further NAT1 alleles must be considered for more conclusive results regarding the relevance of NAT1 activity to colorectal tumorigenesis.