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Biomedical subjects

M J Thomas

Publications and source records attributed to M J Thomas.

At least 217 records · Page 12Linked to original sources
PubMed1976

Vasectomy: a long-term study of its effects on testicular endocrine function in man.

Plasma testosterone, luteinizing hormone (L.H.) and follicle stimulating (F.S.H.) were measured before operation in 39 males, aged 26 to 53 years with 2 to 5 children, seeking vasectomy for contraceptive purposes. These measurements were repeated at 3 and 12 months after vasectomy. Levels of L.H. at 12 months were significantly higher than pre-vasectomy levels, suggesting some degree of decreased Leydig cell function. However, testosterone and F.S.H. levels were similar at the three sampling times. Continuing yearly measurements for at least 5 years are planned.

Adult↗
PubMed1976

A considered approach to sterilization of mentally retarded youth.

A protocol of response to families requesting sterilization for retarded youths was developed, utilizing the multidisciplinary approach already structured in a project of sex education and family planning for handicapped juveniles. We operated on 20 patients over a 3 1/2 -year period. Specific criteria for sterilization eligibility were applied, based on medical diagnosis and psychometric and psychosocial maturity evaluation. Long-term follow-up indicates parental satisfaction, improved school attendance for patients after hysterectomy who were previously unable to cope with menstrual hygiene, and no postoperative depression or increase of sexual activity or sexual exploitation.

Adolescent↗
PubMed1975

Secificity of mouse endocervical cell response progesterone: presence of receptors.

The mouse cervical cell response to progesterone, corticosterone, and androgens was studied in vitro and comparatively by grafts on males. Contrary to the exocervical cells which responded more or less to the three steroid hormones, the endocervical cells responded exclusively to progesterone even in an estrogen free system. This result suggests the existence in the mouse endocervical cells of specific receptors to progesterone and indicates that the squamons cells of the uterine cervix have a different response to steroid hormones depending on where these cells are located.

Androgens↗
PubMed1975

[Effect of acetaldehyde upon the oxidative degradation of glucose by baker's yeast].

Acetaldehyde and glucose are simultaneously oxided by baker's yeast. By the use of 14C-U-glucose, as well as 14C-1 or 14C-6 glucose, it has been possible to demonstrate that glucose oxidation can partially be substituted by acetaldehyde oxidation. Acetaldehyde increases the 14C-1/14C-6 ratio of the evolved carbon-dioxide, thus stimulating the amount of glucose degraded by the phosphogluconate route and decreasing the amount metabolised by the glycolytic pathway.

Acetaldehyde↗
PubMed1972

Radioimmunoassay of human growth hormone: technique and application to plasma, cerebrospinal fluid, and pituitary extracts.

A radioimmunoassay for human growth hormone using activated charcoal is described and its precision, accuracy, and sensitivity are defined. Results are presented for growth hormone measurements in plasma obtained during hypoglycaemia induced with insulin in patients of short stature and during glucose tolerance tests in patients with acromegaly. The method was used to measure growth hormone concentrations in cerebrospinal fluid and in extracts of pituitary tumours. No growth hormone was detected in the cerebrospinal fluid of patients without acromegaly. In patients with acromegaly, the concentration of growth hormone in cerebrospinal fluid was measurable and was considerably elevated in one patient with extrasellar extension of a pituitary tumour. Extracts of chromophobe pituitary tumours contained very small concentrations of growth hormone. In extracts of pituitary tumours removed from acromegalic patients, concentrations fell either below or within the normal range.

Acromegaly↗
PubMed1967

Use of diethylenetriamine penta-acetic acid (D.T.P.A.) in the clinical assessment of total body iron stores.

As a quantitative test of iron storage the six-hour urinary excretion of iron was measured after the intravenous infusion of the iron-chelating agent diethylenetriamine penta-acetic acid (D.T.P.A.). The value of this test in determining the presence and magnitude of the total body iron stores was assessed in patients with diseases of iron storage. In patients with idiopathic haemochromatosis and in their first-degree relatives with increased iron stores as measured by hepatic biopsy, the result of the D.T.P.A. test fell progressively as iron stores were reduced by venesection therapy. There was a significant correlation between the result of the D.T.P.A. test and the excess iron storage as measured retrospectively by the effects of venesection therapy, and also between the D.T.P.A. test and the unsaturated iron-binding capacity (U.I.B.C.) in these patients. In patients with excess iron stores due to diseases other than idiopathic haemochromatosis (e.g., alcoholic cirrhosis, haemochromatosis associated with refractory anaemia) the D.T.P.A. test demonstrated the presence of excess iron stores, but the results were very variable and did not correlate closely with the U.I.B.C. or the degree of hepatic haemosiderin deposits. Unexpectedly high results for the D.T.P.A. test were found in some patients with iron-deficiency anaemia.

Adult↗
PubMedDate not supplied

Ultrastructural contributions to the study of morphological differentiation in malignant mixed (pleomorphic) tumors of salivary gland.

Ultrastructural studies of pleomorphic adenoma have shown a coordinated differentiation of luminal epithelial and modified myoepithelial cells with the latter cells related to processes resulting in the myxochondroid stroma. Five examples of various histologic types of malignant mixed tumor of parotid origin were examined by electron microscopy to see if underlying patterns of tumor cell differentiation and organization matched those of pleomorphic adenoma. Whether they were intracapsular tumors (with or without identifiable pleomorphic adenoma), carcinomas ex pleomorphic adenoma, or a true malignant mixed tumor, all lesions had cell types and organizations either identical to those in pleomorphic adenoma or, as in less-differentiated examples, displayed features suggesting origin from luminal cells, myoepithelial cells, or both. Even the chondroid cells in the true malignant mixed tumor expressed ultrastructural features indicating their epithelial derivation. On the basis of these findings, some alterations to the classification and terminology of the subtypes of malignant mixed tumor are suggested.

Adenoma, Pleomorphic↗
PubMedDate not supplied

Blood usage in transfusion-dependent patients. A theoretical model.

A model for blood requirements of transfusion-dependent patients is presented to relate the transfusion interval in days (I), the percentage fall in hemoglobin (F), and the time in days after a transfusion during which no red cell loss occurs (S). The model applies to both normal blood (S = 0) and to young red cell (YRBC) transfusions, giving I = (S + 120)/(200/F - 1) The model predicts prolongation of transfusion interval by use of YRBCs, and is also of use in establishing whether excess red cell destruction or significant red cell production is present in a transfusion-dependent patient receiving either normal blood or YRBCs.

Anemia, Aplastic↗
PubMedDate not supplied

Relationship between dietary retinol and alpha-tocopherol and lipid peroxidation in rat liver cytosol.

The effects of retinol and alpha-tocopherol-deficient and supplemented diets on the cytosolic concentration of thiobarbituric acid reactive substances (TBARS) in rat liver have been studied. Physiological lipoperoxidation (LPO) was observed in liver cytosol of control rats (TBARS = 0.315 +/- 0.034 nmol of MDA equivalents/mg of liver cytosolic proteins). In retinol-deficient diets there was a decrease in retinolaemia and the absence of retinol in liver cytosol while cytosolic TBARS increased significantly (P less than 0.001). Vitamin E was not found in cytosolic fractions, except in alpha-tocopherol-supplemented diet rats. alpha-Tocopherol-deficient diets induced an absence of vitamin E in the serum and cytosolic TBARS were increased compared to controls (P less than 0.001). Supplementation of the diet with retinol and alpha-tocopherol or both in combination induced a significant decrease in liver cytosolic TBARS (P less than 0.001). Finally the combination of low dietary supplementation with retinol and alpha-tocopherol (ten times the normal diet each) induced the maximum anti-LPO effect.

Animals↗