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Biomedical subjects

R W Carrell

Publications and source records attributed to R W Carrell.

At least 163 records · Page 9Linked to original sources
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

Zinc acetate as a precipitant of unstable haemoglobins.

Whereas the addition of four moles of zinc acetate to one of normal human haemoglobin at pH 7.4 results in a clear solution, addition to unstable haemoglobin results in precipitate formation. Within certain limits no false-positive results are obtained with methaemoglobin, and with fetal haemoglobin. With excess zinc, normal haemoglobin also precipitates, but this process is reversible and can be used for a rapid concentration of dilute solutions of normal haemoglobin.

Acetates↗
PubMed1981

Hemoglobin Brisbane: beta68 Leu replaced by His. A new high oxygen affinity variant.

Hemoglobin Brisbane is a new hemoglobin variant which produces a mile erythrocytosis. It is not detectable by electrophoresis at pH 8.6 or by isoelectric focusing but it is mildly unstable and gives a positive result with standard stability tests. The new hemoglobin has increased oxygen affinity and reduced co-operativity with a normal Bohr effect and 2,3-DPG binding. Structural analysis shows that a histidine residue has replaced the leucine normally found at position beta 68 (E12).

Adult↗
PubMed1980

Ligand-binding properties of proalbumin Christchurch.

Proalbumin Christchurch, a circulating variant of human serum albumin, is secreted from the liver without cleavage of the hexapeptide situated at the N-terminal end of the peptide chain of proalbumin. We compared ligand-binding properties of proalbumin Christchurch and of normal albumin A from the same individual in order to test the effect of the presence of the hexapeptide. The two albumin forms exhibited similar affinities for palmitate, bilirubin, 8-anilinonaphthalene-1-sulphonate and Bromocresol Green. The patterns of endogenous fatty acids bound to the two forms of albumin were slightly different, although the differences were probably not of physiological significance. From these studies it would appear that the propeptide of proalbumin does not alter the protein conformation in such a way as to alter binding sites for organic anions.

Anilino Naphthalenesulfonates↗
PubMed1980

Functional abnormality of proalbumin Christchurch.

Proalbumin Christchurch is a varient of human albumin in which the C-terminal basic residue of the propeptide has undergone a mutation to glutamine. In this investigation spectral and equilibrium dialysis studies have shown that the variant lacks the high affinity copper binding site of normal albumin. A simple electrophoretic procedure is described using 63Ni(II), which allow discrimination of proalbumins from other variants of albumin. The finding that Proalbumin Christchurch is readily cleaved in vitro by trypsin but is secreted uncleaved in vivo is evidence that propeptide cleavage is due to specific proteolysis with paired basic residues being a pre-requisite.

Amino Acid Sequence↗
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↗
PubMed1978

Routine serum lipid analysis in New Zealand.

For two years pairs of serum specimens with a wide range of cholesterol and triglyceride concentrations were regularly dispatched each month to all New Zealand medical laboratories known to measure blood lipids. Four weeks after specimen dispatch each laboratory received a report which displayed all results along with the overall means, standard deviations, and results from "reference laboratories". Six-monthly summaries were prepared for each laboratory in which the previous 12 results were compared with the corresponding "target values" by regression analysis. This allowed classification of inaccuracy into one or more of three categories. Random error (imprecision) explained most of the discrepancies, but systematic errors also contributed strongly to the observed interlaboratory variation. No single class of laboratories performed significantly differently from any others. Approximately 60 percent of the 16000 cholesterol analyses done each month in New Zealand, and 40 percent of the 10000 triglyceride analyses, are performed with precision thought to be adequate for clinical usage.

Cholesterol↗
PubMed1978

Mechanism of oxyhaemoglobin breakdown on reaction with acetylphenylhydrazine.

The reaction of oxyhaemoglobin and acetylphenylhydrazine, which results in haemoglobin denaturation and precipitation, was found to be influenced by H202 and superoxide (O2-.) generated during the reaction. By analysing the different haemoglobin oxidation products, it was found that by influencing the rate at which oxyhaemoglobin was oxidized, H2O2 accelerated the overall haemoglobin breakdown, and O2-. inhibited it. By adding GSH (reduced glutathione) or ascorbate, it was possible to slow down the rates of both oxyhaemoglobin oxidation and O2-. production, and the overall rate of haemoglobin breakdown. These results are compatible with a mechanism involving production of the acetylphenylhydrazyl free radical, and with GSH, ascorbate and O2-. acting as radical scavengers and preventing its further reactions. The reaction produced choleglobin, as well as acetylphenyldiazine and methaemoglobin, which combined to form a haemichrome. The haemichrome was less stable and precipitated first. It was also less stable than the haemichrome formed by direct reaction of acetylphenyldiazine with methaemoglobin, and it is proposed that this is because the methaemoglobin produced from oxyhaemoglobin and acetylphenylhydrazine was modified by the free radicals and H2O2 produced in the reaction.

Azo Compounds↗