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Biomedical subjects

S Hall

Publications and source records attributed to S Hall.

302 records · Page 17Linked to original sources
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Bon voyage.

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Communicable Disease Control↗
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Proficiency testing of eight French laboratories in using the AOAC mouse bioassay for paralytic shellfish poisoning: interlaboratory collaborative study.

In an interlaboratory study, 8 French laboratories were tested for their proficiency in using the AOAC mouse bioassay for paralytic shellfish poisoning (PSP). Each laboratory received 1 saxitoxin (STX) standard solution, 1 STX acidified water solution for determination of the titer, 1 noncontaminated shellfish sample, 1 naturally contaminated shellfish sample, and 2 shellfish samples spiked, respectively, at low (152.8 microg STX/100 g meat) and moderate (334.7 microg STX/100 g meat) levels. All samples were analyzed in duplicate. Mean recoveries were 35.1% for the low level and 46.6% for the moderate level. Relative standard deviations (RSD) for within-laboratory variations (repeatability) ranged from 5.4 to 9.8%; RSD for between-laboratory variations (reproducibility) varied from 7.8 to 39.6%, depending on STX level. On the basis of overall performance, all 8 participating laboratories were proficient in their use of the AOAC mouse bioassay.

Animals↗
PubMedDate not supplied

A study of ten toxins associated with paralytic shellfish poison using prechromatographic oxidation and liquid chromatography with fluorescence detection.

Ten paralytic shellfish toxins [saxitoxin, neosaxitoxin, B-1, B-2, gonyautoxin 1, 2, and 3 (i.e., GTX-1, GTX-2, and GTX-3), C-1, C-2, and C-3] were oxidized at room temperature under mildly basic conditions with hydrogen peroxide or periodic acid. The products were then analyzed by liquid chromatography (LC). The N-1-hydroxylated toxins (neosaxitoxin, B-2, GTX-1, and C-3) formed fluorescent products after periodate oxidation at ca pH 8.7, but did not form fluorescent derivatives with peroxide oxidation. The non-N-1-hydroxylated toxins (saxitoxin, B-1, GTX-2, GTX-3, C-1, and C-2) formed highly fluorescent derivatives with both peroxide and periodate oxidations. Individual toxins produced mainly single fluorescent peaks by reverse-phase LC. However, all GTX toxins eluted with the same retention time. Also, C-1 and C-2 eluted together, as did neosaxitoxin and B-2. The non-N-1-hydroxylated toxins could be detected in quantities as low as 20-50 pg/injection, while the N-1-hydroxy analogues could be detected at levels as low as 100-500 pg/injection. UV absorption and fluorescence emission spectra were similar for the oxidation products of all toxins examined (max. 333 +/- 2 nm absorption, 389 +/- 4 nm fluorescence emission).

Animals↗
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New bone formation in acromegaly: pathogenetic implications for diffuse idiopathic skeletal hyperostosis.

Radiographs of spinal and heel entheseal areas and the skull were examined for new bone formation in 30 acromegalic patients. Forty-seven percent satisfied accepted criteria for Diffuse Idiopathic Skeletal Hyperostosis (DISH), 67% had marked heel enthesopathic change and 87% had Hyperostosis Frontalis Interna (HFI). Such hyperostotic changes were indistinguishable from those seen in DISH and the extent and degree of such changes increased with duration of acromegaly. It is proposed that a common metabolic factor, e.g., hyperinsulinaemia, may be responsible for the hyperostotic changes seen in both DISH and acromegaly.

Acromegaly↗
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Functional ambulation in myelodysplasia: the effect of orthotic selection on physical and physiologic performance.

The metabolic demands of ambulation in a reciprocation gait orthosis (RGO) were compared with those in conventional bracing (hip-knee-ankle-foot orthosis) and wheelchair use in eight myelodysplastic children. Heart rate was significantly increased during swing-through gait compared with that during wheelchair use (p less than 0.01). Oxygen consumption studies showed a significant increase in swing-through gait over that in wheelchair use. These values for RGO use approximated wheelchair use. These results suggest a more favorable prognosis for long-term functional ambulation in higher-level myelodysplastic patients if they are fitted with an RGO.

Adult↗
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Control of renal carcinoma TC-1 growth, cyclin/kinase and nm23 expression by IFN-gamma and TGF-beta.

To gain mechanistic insights into the growth control of renal cell carcinoma cells by IFN-gamma and TGF-beta, a recently established human renal carcinoma TC-1 cell line was treated with different concentrations of IFN-gamma and TGF-beta. Cell growth and changes in specific gene expression were evaluated. IFN-gamma exerted an antimitogenic effect on TC-1 cells, whereas TGF-beta was essentially without effect. The growth-suppressed cells had reduced expression of proliferating cell nuclear antigen (PCNA), the G2/M cell cycle transition regulatory proteins cyclin B/p34cdc2, the tumor suppressor gene pRB, and the antimetastatic gene nm23. However, levels of other cell cycle regulatory protein molecules such as cyclin D and p53 were unaffected by IFN-gamma. Thus, the antimitogenic effect of IFN-gamma may be mediated by its ability to modulate specific oncogene changes.

Carcinoma, Renal Cell↗
PubMedDate not supplied

A dose of the UN's medicine.

Mariam Hamza hit the headlines when she was whisked to Britain from sanctions-hit Iraq to receive leukaemia treatment. Susannah Hall and David Olafimihan report from Iraq on the patients and nurses who were left behind.

Child↗
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Righting human wrongs.

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Ethics, Medical↗
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A guide to common parasitic diseases.

The Primary Health Care Guide to UK Parasitic Diseases is aimed at health professionals working in primary care and offers an easy reference and practical advice on prevention, recognition and management of parasitic disease. Here, some of the key points are summarised.

Humans↗