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Biomedical subjects

D W Moss

Publications and source records attributed to D W Moss.

At least 127 records · Page 7Linked to original sources
PubMed1976

Reactivation of the apoenzyme of aspartate aminotransferase in serum.

Apoenzyme of aspartate aminotransferase in serum can be reactivated conveniently by addition of 100 mumoles/l pyridoxal phosphate to the reaction mixture, without extending the usual minimum pre-incubation period in the operation of the LKB 8600 reaction rate analyzer. Normal sera contain some apoenzyme, the amount of which, as well as that of holoenzyme, is greatly increased by damage to skeletal muscle. This may be due to direct injury or to the indirect effects of anoxia; e.g., following surgery with extracorporeal circulation. Myocardial infarction also increases the levels of both apo- and holoenzymes, but changes in the two levels follow similar time courses and apo- and holo-aminotransferases disappear from the circulation at similar rates.

Apoenzymes↗
PubMed1975

Some properties of alkaline-phosphatases in parenchymal and biliary tract cells separated from rat liver.

Livers of both normal and bile-duct ligated rats have been separated into parenchymal cells and fractions enriched in biliary tract cells. The specific activity of alkaline phosphatase increases in both types of cells after occlusion of the bile duct but the increase is more marked in the case of parenchymal cells. The enzyme from parenchymal cells migrates as a single zone on electrophoresis, whereas additional zones of lower anodal mobility occur in extracts of biliary tract preparations. The alkaline phosphatase activity of the slower zones is significantly less stable to heat than that of the zone characteristic of parenchymal cells. It is postulated that the increase in heat stability of alkaline phosphate in extracts of whole rat liver after bile-duct ligation is due to an increase in the proportion of the more stable form of the enzyme predominant in parenchymal cells.

Alkaline Phosphatase↗
PubMed1975

A simplified heat-inactivation method for investigating alkaline phosphatase isoenzymes in serum.

A method is described for the determination of the percentage of liver alkaline phosphatase in serum samples in which measurements of residual activity are made after incubating the samples for 15 and 25 min at 56 degrees C. This method has the advantage of taking into account quantitative variations in the heat stability characteristics of liver alkaline phosphatase from one sample to another, in contrast to methods in which only a single period of exposure to 56 degrees C is employed.

Alkaline Phosphatase↗
PubMed1975

Incidence and some properties of an electrophoretically slow form of alkaline phosphatase in sera of patients with diseases of the intestine.

A zone of alkaline phosphatase activity migrating at about 40 percent of the rate of liver phosphatase in gel electrophoresis has been detected in sera from 2 out of 22 cases of ulcerative colitis and 1 out of 32 cases of Crohn's disease, but in no other specimen from 33 patients with other diseases of the digestive tract. This rare form of alkaline phosphatase was unlike small-intestinal alkaline phosphatase in several properties. Its appearance in association with diseases of the colon suggests that the rare isoenzyme may originate in that organ. However, the slowly migrating alkaline phosphatase was equally prominent in serum specimens taken before and after operation in one patient who underwent a pan-proctocolectomy for the alleviation of uncontrollable ulcerative colitis.

Alkaline Phosphatase↗
PubMed1975

Analysis of heat inactivation curves of alkaline phosphatase isoenzymes in serum.

The course of the decline in alkaline phosphatase activity during exposureof serum samples to a temperature of 56 degree C can be resolved into two phases. These represent the exponential decay of an enzyme component with an average half-inactivation time of 112 seconds and of a second component with an average half-inactivation time of 456 seconds. The more rapid fall is due to inactivation of bone alkaline phosphatase and the slower to inactivation of liver and, when present, intestinal phosphatases. The half-inactivation times of the different enzyme species show considerable variation from one serum sample to another. The implications of this variation for methods of estimating the relative proportions of alkaline phosphatase isoenzymes by selective inactivation procedures are discussed.

Alkaline Phosphatase↗
PubMed1973

Changes in plasma -glutamyl transpeptidase activity associated with alterations in drug metabolism in man.

A significant rise in plasma gamma-glutamyl transpeptidase activity (GGT) was observed on 13 out of 14 occasions on which patients on long-term treatment with the oral anticoagulant warfarin were given amylobarbitone, quinalbarbitone, or phenazone (antipyrine) for 30 days. In 13 of these 14 studies there was evidence that drug administration had stimulated the rate of warfarin metabolism. One patient showed no increase in plasma GGT activity, yet a significantly increased rate of warfarin metabolism, and another patient showed an increase in plasma GGT activity without a change in warfarin metabolism. When alterations in both plasma GGT activity and plasma warfarin concentration occurred together in response to drug administration the changes followed a similar time course, occurring after about one week of drug administration with maximal changes at about 10 or 15 days. Administration of chlordiazepoxide, diazepam, nitrazepam, and methaqualone did not stimulate the rate of warfarin metabolism in four patients studied, but plasma GGT activity increased significantly in two of these four instances. The implications of these observations in the interpretation of plasma GGT activities are discussed.

Acyltransferases↗