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Biomedical subjects

Douglas D Richardson

Publications and source records attributed to Douglas D Richardson.

3 recordsLinked to original sources

Determination, by inductively coupled plasma mass spectrometry, of changes in cellular metal content resulting from herpes simplex virus-1 (HSV-1) infection.

Metals and metal-containing compounds are known to play important roles in many biological processes, including metabolic and detoxification pathways and the formation and function of proteins. Like all organisms, viruses are expected to contain different metals. These metals, either by themselves or in the form of metalloproteins, may be involved in the virus's ability to infect healthy cells and replicate within them. Identification and speciation of metals in control cells and in cells affected by a virus could be helpful in elucidating infection and replication mechanisms; these might, in turn, be vital to the development of more effective treatments. There has, however, been no extensive investigation of the metals specific viruses contain or affect. The objective of this study was to investigate changes in cellular metal content resulting from herpes simplex virus 1 (HSV-1) infection. Inductively coupled plasma mass spectrometry was used to identify differences between metal concentrations in uninfected and HSV-1-infected mammalian cells. Although it can be assumed that decreases in metal content are a result of cellular response to the virus, increases can be attributed either to cellular response or to the HSV-1 virus itself. Microwave digestion and flow injection methods suitable for small sample volumes were used, and the effects of different virus inactivation procedures were explored. This work is the first step in the identification of metals pertinent to HSV-1 infection and lays the foundation for future studies concentrating on characterization of these metal-associated or containing molecules.

Animals↗

Enhanced cadmium-induced testicular necrosis and renal proximal tubule damage caused by gene-dose increase in a Slc39a8-transgenic mouse line.

Resistance to cadmium (Cd)-induced testicular necrosis is an autosomal recessive trait defined as the Cdm locus. Using positional cloning, we previously identified the Slc39a8 (encoding an apical-surface ZIP8 transporter protein) as the gene most likely responsible for the phenotype. In situ hybridization revealed that endothelial cells of the testis vasculature express high ZIP8 levels in two sensitive inbred mouse strains and negligible amounts in two resistant strains. In the present study, we isolated a 168.7-kb bacterial artificial chromosome (BAC), carrying only the Slc39a8 gene, from a Cd-sensitive 129/SvJ BAC library and generated BAC-transgenic mice. The BTZIP8-3 line, having three copies of the 129/SvJ Slc39a8 gene inserted into the Cd-resistant C57BL/6J genome (having its normal two copies of the Slc39a8 gene), showed tissue-specific ZIP8 mRNA expression similar to wild-type mice, mainly in lung, testis, and kidney. The approximately 2.5-fold greater expression paralleled the fact that the BTZIP8-3 line has five copies, whereas wild-type mice have two copies, of the Slc39a8 gene. The ZIP8 mRNA and protein localized especially to endothelial cells of the testis vasculature in BTZIP8-3 mice. Cd treatment reversed Cd resistance (seen in nontransgenic littermates) to Cd sensitivity in BTZIP8-3 mice; reversal of the testicular necrosis phenotype confirms that Slc39a8 is unequivocally the Cdm locus. ZIP8 also localized specifically to the apical surface of proximal tubule cells in the BTZIP8-3 kidney. Cd treatment caused acute renal failure and signs of proximal tubular damage in the BTZIP8-3 but not nontransgenic littermates. BTZIP8-3 mice should be a useful model for studying Cd-induced disease in kidney.

Acute Kidney Injury↗

Hydride generation interface for speciation analysis coupling capillary electrophoresis to inductively coupled plasma mass spectrometry.

A novel hydride generation (HG) interface for coupling capillary electrophoresis (CE) with inductively coupled plasma mass spectrometry (ICPMS) is presented in this work. The CE-HG-ICPMS interface was applied to the separation and quantitation of common arsenic species. Lack of a commercially available HG interface for CE-ICPMS led to a three concentric tube design allowing alleviation of back pressure commonly observed in CE-HG-ICPMS. Due to the high sensitivity and element-specific detection of ICPMS, quantitative analysis of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid was achieved. Optimization of CE separation conditions resulted in the use of 20 mmol L(-1) sodium borate with 2% osmotic flow modifier (pH 9.0) and -20 kV applied potential for baseline resolution of each arsenic species in the shortest time. Hydride generation conditions were optimized through multiple electrophoretic separation analyses with 5% HCl and 3% NaBH(4) (in 0.2% NaOH) determined to be the optimum conditions. After completion of system optimization, detection limits obtained for the arsenic species were less than 40 ng L(-1) with electromigration time precision less than 1% within a total analysis time of 9.0 min. Finally, the interface was used for speciation analysis of arsenic in river and tap water samples.

Arsenic↗