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Biomedical subjects

G Neale

Publications and source records attributed to G Neale.

At least 91 records · Page 5Linked to original sources

Effect of bile-duct ligation on organelle marker enzymes in the liver and serum of rats.

1. Marker enzymes for the principal subcellular organelles of rat liver were asayed in the liver of rats 1 day and 8 days after bile-duct ligation or after laparotomy as a control procedure. 2. The microsomal enzymes in liver tissue showed complex changes. Benz[alpha]pyrene hydroxylase activity, predominantly found in the smooth endoplasmic reticulum, was decreased. Glucose 6-phosphatase activity and ribonucleic acid, which are localized predominantly in the rough endoplasmic reticulum, were increased. 3. The plasma membrane enzyme, alkaline phosphatase, increased in activity after bile-duct ligation. 4. No changes in mitochondrial enzyme activities were noted after 1 day but there was a 50% reduction 8 days after ligation. Lysosomal enzyme activities did not change in the liver tissue. 5. Liver catalase and D-amino acid oxidase activities showed a slight increase at 1 day postligation but a significant fall by 8 days. 6. Lactate dehydrogenase, a cytosol enzyme, showed a decrease in activity after 1 day but an increase in tissue activities 8 days after ligation. 7. Serum activities of mitochondrial, plasma membrane, microsomal, lysosomal and cytosol marker enzymes tended to increase post-ligation, particularly at 8 days. 8. Monoamine oxidase, a predominantly mitochondrial enzyme, was greatly elevated in the serum after 1 day but had returned to normal activities by 8 days.

Acetylglucosaminidase↗

Indices of granulocyte activity in inflammatory bowel disease.

In conditions with increased neutrophil production, the serum total vitamin B(12)-binding capacity (TBBC) is considered to correlate with the blood pool size of neutrophil granulocytes. The serum lysozyme, on the other hand, is a measure of neutrophil (and monocyte) turnover. The mean serum TBBC was significantly raised in patients with ulcerative colitis (range 1.23-5.51 ng/ml; mean 2.64 ng/ml) and patients with Crohn's disease (range 1.58-9.29 ng/ml; mean 2.93 ng/ml). The elevated values were shown to be due to rises in the granulocyte-secreted binding proteins, transcobalamins I and III. The TBBC was shown to rise with increasing activity of disease and to correlate roughly with the blood neutrophil granulocyte count. Patients with inflammatory bowel disease also had a significantly raised mean level of serum lysozyme (range 3.1 to 10.4 mug/ml; mean 6.8 mug/ml), but there was no correlation in individual patients between serum lysozyme and total B(12)-binding capacity. These results are taken to indicate an enlarged granulocyte pool and increased granulocyte turnover in inflammatory bowel disease.

Adolescent↗

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↗

Liver structure and function following small bowel resection.

The observation that patients with extensive small bowel resection have impaired hepatocellular function with reduced BSP clearance and fatty change in biopsies from the liver led to a systematic study of liver structure and function following proximal and distal small bowel resection in the rat. While anaesthesia and surgery impaired BSP clearance per se, small bowel resection further reduced BSP clearance with impairment of both uptake and excretion phases of BSP excretion. The increased BSP retention was more marked after distal than after proximal small bowel resection, but in both experimental groups the abnormalities of BSP excretion spontaneously returned to normal three to four weeks after surgery. Circulating liver enzymes were normal but serum alkaline phosphatase was significantly depressed, particularly after distal resection. Isoenzyme studies showed that the depression of serum AP was due to a reduced intestinal isoenzyme. While serum levels remained consistently depressed up to eight weeks after proximal resection, in parallel with mucosal regeneration, serum AP returned to normal two to four weeks after ileectomy. While these minor changes in hepatic structure and function would normally be of little clinical importance, the additional insult of hepatic dysfunction may well be important in malnourished patients after extensive small bowel resection.

Adult↗

Serum -glytamyl transpeptidase activity in liver disease.

Serum gamma-glutamyl transpeptidase (GGT) activity correlates closely with the activities of alkaline phosphatase (ALP) and 5'-nucleotidase (5NT) in various forms of liver disease. Maximum elevations of all three enzyme activities are observed in diseases which particularly affect the biliary tract. Compared with the other two enzymes GGT is generally increased to a greater extent and is thus the most sensitive indicator of biliary-tract disease, while estimations of serum GGT are more reproducible than those of 5NT. However, a group of patients who had been treated with phenytoin and barbiturates were found to have elevated serum GGT activities without any other evidence of liver disease. The apparent effect of certain drugs on serum GGT activity indicates the need for caution in interpreting the results of this test.

Acyltransferases↗