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Biomedical subjects

W C Thomas

Publications and source records attributed to W C Thomas.

At least 37 records · Page 2Linked to original sources
PubMed1984

The subchronic oral toxicity of polyphenylene sulfide.

Polyphenylene sulfide was offered to Charles River CD rats for 6 months in the diet at concentrations of 0.00, 0.50, 2.75 and 5.00% (w/w). In this study, animals of both sexes consumed polyphenylene sulfide for 6 months without exhibiting compound-related effects. Parameters studied were: body weight, hematology, clinical chemistry, urinalysis, organ weights, gross pathology and histopathology.

Animals↗
PubMed1984

Relationship between experimentally induced crystalluria and relative supersaturation of various stone salts in rats.

Calcium oxalate crystalluria was induced in laboratory rats by subcutaneous implantation of potassium oxalate containing mini-osmotic pumps in their intercapsular region. Concentrations of major urinary ions were measured and urinary supersaturations of various urinary salts were calculated using a computer programme. The urines of experimental animals that received oxalate had calcium oxalate crystals and higher supersaturations for calcium oxalate compared to their controls. Oxalate levels of the urines of experimental animals were higher than their controls and this increase was proportional to the increase in urinary supersaturation of calcium oxalate. No significant difference was found in the calcium levels of urines from experimental and control animals.

Animals↗
PubMed1982

Trace metal-citric acid complexes as inhibitors of calcification and crystal growth. I. Effects of Fe(III), Cr(III) and Al(III) complexes on calcium phosphate crystal growth.

The crystal growth of calcium phosphate has been shown to be inhibited by a low molecular weight Fe(III)-citric acid complex formed when there are high ratios of citrate:iron at neutral pH in aqueous solution. Synergism with citric acid was also observed in systems containing Al(III) or Cr(III) ion, but different unknown complexes seemed to be involved. These results are in qualitative agreement with a preceding study involving calcification of an organic matrix. Since chelating agents like citric acid can compete with the storage proteins for iron, we suggest that the Fe(III)-citrate complexes studied here may be formed in vivo and participate in regulating biologic calcification.

Aluminum↗
PubMed1982

Trace metal-citric acid complexes as inhibitors of calcification and crystal growth. II. Effects of Fe(III), Cr(III) and Al(III) complexes on calcium oxalate crystal growth.

The high molecular weight Fe(III)-citric acid complex, formed at low ratios of citrate:iron in solution, has been shown to be an effective inhibitor of calcium oxalate crystal growth. This appears to be a specific reaction, since 2 other similar metal ions. Al(III) and Cr(III), exhibit no synergism with citric acid in this system. Because the low molecular weight Fe(III)-citric acid complex, formed at high ratios of citrate:iron, inhibits calcium phosphate precipitation but has no effect on calcium oxalate, the Fe(III)-citric acid system might have a selective biologic role in regulating the growth of calcium-containing urinary calculi in vivo.

Aluminum↗
PubMed1981

Evaluation of the genetic activity of industrially produced carbon black.

Commercially produced oil furnace carbon black (Chemical Abstract Service Registry No. 1333-86-4) has been evaluated by five different assay for genetic activity. These were the Ames Salmonella typhimurium reverse mutation test, sister chromatid exchange test in CHO cells, mouse lymphoma test, cell transformation assay in C3H/10T1/2 cells, and assay for genetic effects in Drosophila melanogaster. Limited cellular toxicity was exhibited but no significant genetic activity was noted.

Air Pollutants↗
PubMed1979

Cushing's disease with cyclic hormonogenesis and diabetes insipidus.

A cyclic excess of cortisol secretion was detected in a patient with diabetes insipidus and diabetes mellitus. The cycles of hypercortisolism were of 7 days' duration, but during the nadir of these cycles urinary excretion of corticosteroids and 17-ketosteroids was within the normal range. The radiological appearance of the sella turcica was normal; however, computerized axial tomography of the head revealed a small tumor immediately superior to the sella turcica. At operation a small chromophobe adenoma superior to the diaphragma sellae and involving the hypophysial stalk was partially resected. Postoperatively, the patient continued to have 7-day cycles of increased corticosteroid excretion, but the amounts excreted were less than they had been preoperatively. Other patients have been described in whom Cushing's disease has been due to cyclic hypercortisolism. These cycles have been remarkably regular in individual patients, but of variable duration in different patients. Furthermore, cyclic hormonogenesis probably occurs in a variety of endocrinopathies. (Neurosurgery, 5: 598--603, 1979).

17-Hydroxycorticosteroids↗