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Biomedical subjects

D Williamson

Publications and source records attributed to D Williamson.

At least 91 records · Page 5Linked to original sources
PubMed1983

A radioimmunoassay for tauro-beta-muricholic acid suitable for use with isolated rat liver cells.

A new radioimmunoassay which can be used to measure the amounts of tauro-beta-muricholic acid produced by isolated rat hepatocytes in vitro is described. Cross reactivities of other bile acids known to be present in rat liver with the antiserum used in the assay were not sufficient to interfere with the measurement of tauro-beta-muricholic acid. Exogenous taurochenodeoxycholic acid was metabolised by isolated rat hepatocytes concurrently with the appearance of tauro-beta-muricholic acid in the cell.

Animals↗
PubMed1983

Hepatitis B surface antigen in human subretinal fluid.

Body fluids containing hepatitis B surface antigen are considered to be potential sources of hepatitis B infection. This antigen has been detected in blood, oral secretions, synovial fluid, urine, feces, bile cerebrospinal fluid, pleural and peritoneal fluid, semen, vaginal secretions, breast milk, and tears. These fluids are probably not equally infectious, however, because the concentration of virus in a particular fluid may be low when compared to that in blood. For instance, in hepatitis B carriers whose tears were positive for hepatitis B surface antigen, the concentration of hepatitis B surface antigen in the tears averaged less than one-fifteenth the average value found in serum.

Adult↗
PubMed1983

Two unstable hemoglobins in one individual: Hb Atlanta (beta 75 Leu leads to Pro) and Hb Coventry (beta 141 Leu deleted).

A 25-year-old male had a life long history of a hemolytic anemia which was shown to be due to the presence of an unstable hemoglobin, Hb Atlanta beta 75 Leu leads to Pro. Two dimensional peptide maps of isopropanol precipitated globin also showed the presence of a second variant, Hb Coventry beta 141 Leu deleted. HPLC separation of the tryptic peptides consistently demonstrated both the abnormal and normal beta 9 and beta 14 peptides in the digest of total globin. Neither of the abnormal peptides was apparent on similar maps of globin from his parents or his two siblings. The proportion of the variants measured from the peptide maps was 11% beta-Coventry, 34% beta-Atlanta and the remainder beta-A. The possible basis for the presence of three beta-globins is discussed and it is concluded that this is likely to be due to some mechanism other than a beta-delta cross-over.

Adult↗
PubMed1981

Unstable haemoglobin haemolytic crises: contributions of pyrexia and neutrophil oxidants.

Pyrexia and the production of oxidants by phagocytic cells have been examined as two possible causes of haemolytic crises associated with infections in carriers of unstable haemoglobins. Three unstable haemoglobins were examined, both in red cells and after purification. Incubation at 40 degrees C rather than 37 degrees C resulted in only a slight increase in autoxidation rate, but a considerable increase in the rate of precipitation of the haemoglobins as Heinz bodies. Oxidants produced by activated neutrophils were capable of oxidizing haemoglobin both in solution and red cells, though there was no preferential effect on the unstable as opposed to the normal haemoglobin. It is concluded that haemolytic crises associated with infections in carriers of unstable haemoglobins can be explained by increased intracellular precipitation of the haemoglobin as Heinz bodies caused by the accompanying pyrexia.

Heinz Bodies↗
PubMed1981

Oxidative hemoglobin breakdown induced by a rubber additive.

An antioxidant commonly present in black rubber, N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD) caused very rapid oxidation and denaturation of purified hemoglobin. In the red cells, the reaction resulted in the formation of Heinz bodies, a decrease in reduced glutathione concentration, and stimulation of the hexose monophosphate shunt. IPPD appears therefore to have the potential to induce hemolysis in glucose-6-phosphate dehydrogenase deficiency. It would be expected to be more potent than most redox reagents of this type. It does not require further metabolism to be reactive, and its reactivity is similar to that of phenylhydrazine. But in particular since both IPPD and its oxidized form can oxidize hemoglobin it can act catalytically, and at low concentrations is much more effective than phenylhydrazine. Oxidation of blood stored in contact with rubber seals containing IPPD has been observed. It is also possible that prolonged contact of susceptible individuals either with rubber containing IPPD or to IPPD itself during rubber manufacture could result in hemolysis.

Anemia, Hemolytic↗
PubMed1980

A note on the transformation of the dbrB carcionoma.

A heterofore strain-specific mammary carcinoma of the mouse was found to have acquired altered characteristics. The dbrB transplantable tumor originated in a DBA mouse as a spontaneous carcinoma in 1918. It was not until recently, when this tumor was transferred from mice to storage in the frozen state, that a marked transformation occurred both in vivo and in vitro. Certain morphologic differences were also noted.

Animals↗
PubMed1980

Hemoglobin Volga, beta 27 (B9) Ala replaced by Asp: functional and clinical correlations of an unstable hemoglobin.

Hb Volga (beta 27 Ala replaced by Asp) on the basis of physical tests is only a mildly unstable hemoglobin yet it is associated with a gross reticulocytosis. This is partly explicable by an increased oxygen affinity with a compensating erythrocytosis but there is also brisk hemolysis. It is not certain that this hemolysis is due to precipitation of the hemoglobin as in vitro inclusion body formation is not remarkable and there is no evidence of preferential proteolysis of the abnormal subunits, at least in the reticulocytes. There is increased autoxidation and it may be the consequence of this that is the prime cause of hemolysis.

Alanine↗