PubMed · 14146725
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J G ADAMS. 1964. HYPERBARIC OXYGEN THERAPY.. https://pubmed.ncbi.nlm.nih.gov/14146725/
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Tobacco mosaic virus (TMV) is an intensely studied model of viruses. This paper reports an investigation into the dissociation of TMV by pH and pressure up to 220 MPa. The viral solution (0.25 mg/ml) incubated at 277 K showed a significant decrease in light scattering with increasing pH, suggesting dissociation. This observation was confirmed by HPLC gel filtration and electron microscopy. The calculated volume change of dissociation (DeltaV) decreased (absolute value) from -49.7 ml/mol of subunit at pH 3.8 to -21.7 ml/mol of subunit at pH 9.0. The decrease from pH 9.0 to 3.8 caused a stabilization of 14.1 kJ/mol of TMV subunit. The estimated proton release calculated from pressure-induced dissociation curves was 0.584 mol H(+)/mol of TMV subunit. These results suggest that the degree of virus inactivation by pressure and the immunogenicity of the inactivated structures can be optimized by modulating the surrounding pH.
Food safety represents one of the main issues of national and international agencies appointed to health control. In April 2003, a French agency disclosed that powdered or smashed hot chili pepper imported from India and Pakistan was heavily contaminated with a carcinogenic azo dye known as Sudan I. This paper deals with a modern approach for assaying the content of this colorant in foodstuff down to a limit of a few tens of parts per billion. The isotope dilution method combined with APCI tandem mass spectrometry was used. The internal standard, 1-(d5-phenylazo)-2-naphthalenol, was obtained by simple chemistry, and its structure was determined by 1H NMR spectroscopy. The mass spectrometric method is more sensitive than the HPLC approach by a factor of 20.
Hereditary paraganglioma (PGL) is characterized by the development of slow-growing and vascularized tumors in the paraganglionic system. PGL is caused by germ line heterozygous inactivating mutations in the SDHB (PGL4), SDHC (PGL3), or SDHD (PGL1) genes, which encode three of the four subunits of mitochondrial complex II (succinate dehydrogenase; SDH). Common tumor sites include the carotid body in the neck and paraganglia in the abdomen. The risk of tumor development associated with SDHD mutations is determined by the sex of the transmitting parent, because only a paternal transmission leads to tumorigenesis in the progeny. This transmission pattern suggests operation of genomic imprinting on the SDHD gene. There is also evidence that the risk of tumor development increases at higher altitudes among SDHD mutation carriers. Accordingly, the increased prevalence of SDHD mutations in the Netherlands, attributable to multiple founder mutations, has been explained in part by the low altitudes in this country, which presumably reduce gene penetrance and relax the natural selection. Thus, PGL caused by SDHD mutations represents an unusual example of an inherited monogenic tumor syndrome because the risk of tumorigenesis shows an absolute dependence on the sex of the transmitting parent and may be modified by a ubiquitous environmental factor.