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Biomedical subjects

L R Purves

Publications and source records attributed to L R Purves.

At least 37 records · Page 2Linked to original sources
PubMed1980

Sites of D-domain interaction in fibrin-derived D dimer.

We have examined the plasmic digestion products of fibrin formed in the presence of dansylcadaverine, the fluorescent D dimer, to determine whether they are held together not only by the cross-link region on the gamma chain but also by other interactions on the D domain. Antibodies to the D dimer reacted 8X more strongly with sites on the D dimer (purified or in the presence of E) than with sites on fibrinogen or plasmin-digested fibrinogen. The reactivity of this surface site was lost when the gamma chain was cleaved by plasmin after the molecule had been destabilized by the removal of calcium ions, thus breaking the covalent linkage of the homodimer. The noncovalent D dimer retained its dimeric structure by the criteria of molar volume, measured by fluorescence polarization, and molecular sieving. The noncovalently attached, cross-link-containing peptide bound tightly to the parent molecules at higher temperatures but rotated more freely below 15 degrees C, and could be lost from the parent molecules without destroying the dimeric structure. We therefore propose that the forces maintaining the dimeric structure of the noncovalently joined molecule are not solely located at the gamma-chain cross-link region. These other sites on the D domain are therefore candidates for the initial fibrinogen polymerization site and may also have a role in fibrinogen half-molecule assembly.

Animals↗
PubMed1979

An abnormal macro lactate dehydrogenase isoenzyme not due to immunologlobulin binding.

We report here on the lactate dehydrogenase (LD) of a patient who presented with an additional LD isoenzyme band between LD 3 and LD4 found during routine examination. The abnormal LD was found to be of increased molecular size, which was not due to complexing with immunoglobulins. The abnormal LD was purified by affinity chromatography, labelled and electrophoresed on a SDS-polyacrylamide gel. Autoradiography suggested abnormal aggregation as the cause of increased molecular size.

Aged↗
PubMed1979

The carbohydrate prosthetic groups of rat fibrinogen plasmic fragment E.

Rat fibrinogen plasmic fragment E was found to contain one oligosaccharide chain per gamma-chain attached by a glycosylamine linkage. The oligosaccharide was composed of 1 sialic acid, 1 galactose, 2 mannose and 2 glucosamine residues. The probable sequence from the nonreducing end was sialic acid leads to galactose beta leads to mannose alpha leads to mannose alpha leads to glucosamine leads to glucosamine. No difference in the rate of clearance from the rat circulation could be detected between native and desialated fragment E. A non-denaturing method for the purification of fragment E is described.

Animals↗
PubMed1978

The hyperviscosity syndrome in an IgA-2 myeloma patient.

We have compared serum viscosities in 2 patients with the IgA type of multiple myeloma. One patient had the rare condition of IgA-2 myeloma. We confirm that hyperviscosity is associated with higher polymers. It would appear that there is no barrier to polymer formation with the IgA-2 subclass.

Blood Protein Electrophoresis↗
PubMed1978

alpha-Fetoprotein in liver disease.

Ther serum concentration of alpha-fetoprotein (AFP) was measured by radio-immunoassay in 98 patients with liver disease including hepatoma, chronic active hepatitis, alcoholic cirrhosis, and acute virus B hepatitis. Raised AFP levels, above 30 ng/ml, were found in 87% of patients with acute viral hepatitis, in 82% of patients with primary liver cell carcinoma, in 58% with chronic active hepatitis and in 14% of patients with alcoholic cirrhosis. However, levels above 1 000 ng/ml were found only in patients with hepatoma and in acute viral hepatitis.

Adolescent↗
PubMed1975

A spatial and temporal analysis of four cancers in African gold miners from Southern Africa.

The pattern of cancer in African gold miners over the 8-year period 1964-71, comprising 2,926,461 man-years of employment was studied. Of the 1344 cancers found, primary liver cancer accounted for 52-8%, oesophageal cancer 12-1%, cancer of the respiratory system 5-4% and cancer of the bladder 4-8%. Analysis of the spatial distribution of these four cancers, both on subcontinental and local scale, showed distinct gradients of occurrence between areas of significantly higher and lower incidence than expected. In the case of primary liver cancer in Mozambique and oesophageal cancer in the Transkei, the spatial distribution reflects closely that found in the general resident population of each territory. The crude incidence rate of primary liver cancer in gold miners from Mozambique dropped sharply over the period of the survey.

Africa, Southern↗
PubMed1973

Serum alpha-fetoprotein levels in acute viral hepatitis.

Serum alpha-fetoprotein levels were measured serially by radioimmunoassay in 32 patients with acute viral hepatitis. With one exception, the levels were increased during the course of the illness. Raised concentrations of the protein occurred almost equally in patients with and without the hepatitis-B antigen. In the majority of patients the rise was modest but in seven levels were reached at which alpha-fetoprotein could be detected by immunodiffusion. Very high levels were more likely to occur in children. In eight patients the concentration increased as the serum glutamic pyruvic transaminase (SGPT) level, used as an index of hepatocyte damage, was returning to normal, a pattern which favoured increased synthesis of the protein during hepatocellular regeneration. In the remainder, the alpha-fetoprotein level paralleled that of SGPT, suggesting rather an acutephase reaction to liver injury.

Adolescent↗