Biomedical subjects
J V Martin
Publications and source records attributed to J V Martin.
Lipid profiles in dioxin-exposed workers.
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Elevation of serum alkaline phosphatase activity and related enzymes in diabetes mellitus.
Of 101 consecutive hospitalised diabetic patients, 29 had elevated serum enzyme activities attributable to recognized clinical entities; 17% of the remainder had raised alkaline phosphatase (AP) activity, 15% had raised aspartate aminotransferase (GOT) activity, and 12% raised lactate dehydrogenase (LDH) activity in serum. Ketoacidosis and death within 3 months were commoner among patients with elevated serum enzyme activities than among those with normal enzymes. Study of 200 consecutive new untreated diabetics when first seen at an out-patient clinic revealed 15 with clinically explainable abnormal serum enzyme activities. Of the remainder, 11% had raised AP activity, 12% raised GOT activity, and 21% raised LDH activity in serum; these patients tended to have higher blood sugar concentrations than the subjects with normal serum enzymes. These abnormalities seem to be an intrinsic feature of diabetes mellitus which do not relate to duration, complications, or treatment of the disease. They do not seem to be directly related to hepatic involvement.
Enzyme inducation as a possible cause of increased serum-trigylcerides after oral contraceptives.
Serial studies on twenty patients before and during oral-contraceptive therapy demonstrated a significant positive association between serum gamma-glutamyl-transpeptidase (G.G.T.) activity and triglyceride concentrations, both of which rose after treatment. The association between serum G.G.T. and triglyceride, and their increase after treatment with oral contraceptives, may reflect hepatic microsomal enzyme induction of both the rate-limiting enzymes of triglyceride synthesis, and G.G.T.
The association between serum triglycerides and gamma glutamyl transpeptidase activity in diabetes mellitus.
A study conducted on 228 diabetic patients has shown a significant positive association between serum gamma-glutamyl transpeptidase (GGT) and triglyceride levels. Both fall with treatment, the most marked reduction occurring in patients on insulin. We suggest that the association between serum GGT and triglyceride levels and also the higher incidence of raised GGT and triglyceride levels in new diabetics may reflect hepatic microsomal enzyme induction of the rate-limiting enzymes of triglyceride synthesis. Serum GGT does not seem to correlate with hepatomegaly in diabetes mellitus.
The excitation and inhibition of sexual receptivity in female hamsters by progesterone: time and dose relationships, neural localization and mechanisms of action.
Ovariectomized hamsters were administered estradiol benzoate (EB) and 44 h later, progesterone (P.) Lordosis behavior was induced. When an additional dose of P was given up to 24 h prior to or 24 h after the EB, EB-P facilitation of lordosis was inhibited. Additional hamsters were given varying doses of P (25-200 mu) following EB using both excitatory and inhibitory paradigms. Inhibition of EB-induced lordosis was effected with a lower dose of P than was the facilitation of EB induced lordosis by P. Hamsters were also given intracerebral implants of P using excitatory and inhibitory paradigms. No excitatory loci were found. Inhibition of EB-induced lordosis was effected by implants in the posterior hypothalamus and anterior mesencephalon, but not by diencephalic implants. Other hamsters were administered tritiated estradiol (E2) plus P prior to, concurrent with, or shortly after the E2. P had no effect upon the accumulation of E2 by any brain sites, although E2 was found to concentrate to a greater degree in the diencephalon than in the mesencephalon or cortex. The estrogen-induced depletion and replenishment of hypothalamic cytosol estrogen receptors was also studied. Concurrent P treatment had no effect upon the receptor depletion-replenishment process. It was concluded that P can both facilitate and inhibit estrogen-induced lordosis and that the inhibitory effects of P are not upon estrogen-sensitive cells in the brain.
Effect of oestrogen antagonist on hypothalamic oestrogen receptors.
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Pitfalls in assay and interpretation of serum gammaglutamyl transpeptidase activity.
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Gamma-glutamyl transpeptidase, triglycerides, and enzyme induction.
A study conducted on 109 consecutive patients submitted for routine lipid and lipoprotein screening has shown a significant positive association between serum gamma-glutamyl transpeptidase (gamma-GT) activity and the serum triglyceride concentration and between serum gamma-GT activity and the serum pre-beta-lipoprotein concentration. We suggest that these associations may reflect hepatic microsomal enzyme induction in hyperlipidaemic subjects which increases the hepatic content of the rate-limiting enzyme(s) for triglyceride synthesis.
Role of gamma-glutamyl transpeptidase activity in the diagnosis of hepatobiliary disease.
The enzyme gamma-glutamyl transpeptidase is widely distributed throughout the body, notably kidney, seminal vesicles, pancreas, liver, spleen and brain. Being one of the enzymes of the gamma-glutamyl cycle, it is involved in aminoacid transport, catalysing a transpeptidation reaction between gamma-glutamyl peptides and most common amino acids. Methods of assay of the enzyme are based on its ability also to act on synthetic amides of glutamic acid; kinetic methods monitoring the release of p-nitroaniline from the substrate L-gamma-glutamyl p-nitroanilide are the most satisfactory. In diseases of the liver, the highest levels occur in association with cirrhosis, alcoholism, hepatic secondaries and cholestasis. As the enzyme is present in the endoplasmic reticulum of the hepatocyte, its activity is increased in situations leading to microsomal enzyme induction. Raised levels can also occur in pancreatitis, diabetes, myocardial infarction, congestive cardiac failure, chronic renal failure, cerebrovascular accidents, cerebral tumours and chronic obstructive pulmonary disease. Although the lack of specificity must be recognised, the estimation can be useful in the elucidation of some clearly defined problems arising during investigation of patients with suspected hepatic disease, especially where performed as part of a biochemical profile.
Regional intestinal absorptive capacities for triolein: an alternative to markers.
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