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Biomedical subjects

R C Williams

Publications and source records attributed to R C Williams.

At least 505 records · Page 28Linked to original sources
PubMed1975

In vivo effect of bile salts and cholestyramine on intestinal anaerobic bacteria.

In vitro studies have shown that some bile salts inhibit the growth of intestinal bacteria. We investigated the possibility that bile salts might have a similar action in vivo in the ileum by performing serial anaerobic cultures and bile salt analyses on postprandial ileal fluid obtained anaerobically via intestinal tube. Five subjects were studied under control conditions, and after a 1-week course of orally administered cojugated bile salts in a dose shown to increase the bile salt pool. Three of the subjects were also studied after a 1-week course of cholestyramine. The numebr of ileal anaerobic microorganisms decreased significantly after both bile salt and cholestyramine treatment. Ileal bile salt concentrations were generally high (mean 9.2 mM) and did not change significantly after either bile salt or cholestyramine treatment. The results of this study are unexplained. Although it is possible that bile salts play a role in the regulation of small intestinal anaerobic flora, the lack of a relationship between ileal bile salt concentration and population levels of anaerobic organisms is puzzling and raises further questions about such a role for bile salts.

Adult↗
PubMed1974

Microtubules from mammalian brain: some properties of their depolymerization products and a proposed mechanism of assembly and disassembly.

Depolymerization products of purified microtubules from porcine brain were examined by sedimentation analysis and electron microscopy. The complete depolymerization mixture exhibited 36S and 6S components in concentration-dependent equilibrium, whether depolymerization was caused by low temperature or by calcium ion. These components were recognized by electron microscopy as spirals and rings, and small particles. Agarose column chromatography yielded two major fractions, a leading one comprising mostly 36S and some 6S material and a trailing one of solely 6S material. The latter had high specific colchicine-binding activity and no tendency to polymerize. For the leading peak material these properties were the converse. It is proposed that tubulin molecules (of mass 110,000 daltons) exist in two states, here called X and Y, with those of the X-state equivalent to the material found predominantly in the trailing fraction, and those of the Y-state equated with the material in the leading fraction. Participation of tubulin molecules in microtubule assembly and disassembly is discussed, based on the assumption that those of both states have longitudinal and lateral binding domains whose strengths differentially depend upon temperature and calcium-ion concentration.

Animals↗
PubMed1974

The quaternary structure of delta-aminolevulinic acid dehydratase from bovine liver.

The quaternary structure of delta-aminolevulinic acid dehydratase (5-aminolaevulinate hydrolyase, EC 4.2.1.24) from bovine liver was examined by analytical ultracentrifugation, polyacrylamide gel electrophoresis, and electron microscopy. The molecular weights, determined by sedimentation-velocity and sedimentation-equilibrium experiments, were 289,000 and 282,000, respectively. The molecular weight of the subunit in 6 M guanidine. HCl was 34,900 as determined by sedimentation-equilibrium and 35,000 as estimated by polyacrylamide gel electrophoresis. No evidence was obtained for the presence of a smaller polypeptide. It appears therefore that delta-aminolevulinic acid dehydratase from liver is composed of eight subunits. The molecules of the enzyme deposited in thin layers of negative stain were generally square with an edge length of 85-90 A. On the assumption that the subunits are spherical in shape with a diameter of 44 A and a density of 1.36 g/cm(3), the molecular weight of the octamer is calculated to be 292,000. The particles appear to consist of four discrete lobes arrayed at the four corners of a square. The above conclusion that the dehydratase possesses eight subunits can be readily reconciled with the appearance of the enzyme in the electron microscope if it is postulated that the eight subunits are arranged at the corners of a cube. Therefore, it would follow that the subunits are arranged with dihedral (D(4)) symmetry.

Animals↗
PubMed1974

Immunological studies of anergic patients.

Sixty-one patients with a variety of different illnesses were studied with respect to skin test anergy and the presence of serum chemotactic inhibitors. In initial testing, 55% of the patient tests demonstrated negative skin test responses to all six test antigens. Sera from 65% of these anergic patients were capable of suppressing the migration of normal polymorphonuclear leukocytes toward chemotactic factors. Statistical analysis of the association of anergy and chemotactic inhibitory sera resulted in a P value of <0.0005. Chemotactic inhibitory sera were also capable of suppressing monocyte chemotaxis. No association of chemotactic inhibitory activity and lymphocytotoxic antibody or suppressors of mitogen-induced lymphocyte blast transformation were noted. In addition, T-cell populations in some anergic patients were studied by the erythrocyte-binding technique. Erythrocyte-binding lymphocytes in anergic patients were significantly suppressed when compared to normal controls, but not when compared to skin test-positive patients. The data presented here indicate a close parallel between skin test anergy and the presence of serum chemotactic inhibitory activity. The exact relationship is yet undefined but may indicate the involvement of chemotactic inhibitors as immunological regulators in the host during a variety of systemic illnesses.

Journal Article↗
PubMed1974

Studies of peripheral blood T-and B-lymphocytes in acute infections.

E-binding (T) and immunoglobulin-bearing (B) lymphocytes were determined in 22 patients with acute infections. The percentage of T-cells was depressed in most patients in the early stages of disease, whereas the B-cell proportion was usually elevated compared with convalescence and controls. The B-cell increase occurred earlier in a small group of viral or mycoplasmal infections than in bacterial infections. Four patients with unusually high numbers of B-cells had no corresponding increase in EAC3-binding lymphocytes. Almost all lymphocytes from pleural effusion in a patient with tuberculosis were found to be T-cells.

Acute Disease↗
PubMed1974

T and B lymphocytes in peripheral blood and tissue lesions in Sjögren's syndrome.

Lymphocyte heterogeneity was studied in peripheral blood and salivary gland lesions in 24 patients with Sjögren's syndrome. Peripheral blood B cells, measured by immunofluorescence with specific antiserum to immunoglobulins or by rosette assay with complementcoated erythrocytes, were increased in most patients. Peripheral blood T cells, measured by immunofluorescence with rabbit antiserum to human thymocytes or by rosette assay with sheep erythrocytes, were reduced in eight patients. Three had associated rheumatoid arthritis, two had a generalized lymphoproliferative disorder, and one each had scleroderma, systemic lupus erythematosus, and neuropathy. The salivary gland lymphocytic infiltrates present in labial biopsy specimens were compared in 10 patients using an indirect immunofluorescent method with anti-human T cell serum and a quantitative focus-scoring method. In general, there was a correlation between the number of T cells and the extent of the infiltrate. Striking accumulations of T cells were present in some patients, but clusters of presumed B cells were also seen. These results indicate an increase in peripheral blood B cells in most patients, a decrease in T cells in some, and a mixed T and B cell infiltrate in the salivary gland lesions.

Adult↗