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Biomedical subjects

M Vasta

Publications and source records attributed to M Vasta.

13 recordsLinked to original sources

Alterations in Na+/K(+)-ATPase activity and fluidity of erythrocyte membranes from relatives of insulin dependent diabetic patients.

Several plasma membrane alterations have been described in diabetes mellitus. Data reported in gestational diabetes mellitus (GDM) suggested that these alterations might be present before the onset of overt metabolic derangement. On the basis of these data it is tempting to hypothesize that the reduction in the sodium pump activity might be due to a genetic factor acting at the membrane level before the onset of diabetes. In order to verify this hypothesis 11 insulin-dependent diabetic patients, 15 first degree relatives of the patients and 10 healthy subjects with a negative family history for diabetes mellitus were studied. Fluidity, Na+/K(+)-ATPase activity and membrane cholesterol content (C) were evaluated on plasma membranes obtained from red blood cells (RBCs). Na+/K(+)-ATPase activity was reduced with a contemporary increase in membrane fluidity in RBCs from IDDM patients in comparison to either relatives and controls. The same alterations were observed also in RBCs from the relatives in comparison to controls. We did not find any significant difference in the C content among the three groups. Data herein reported provide evidence that a reduction in the Na+/K(+)-ATPase activity is present in the plasma membrane of relatives of diabetic subjects. Furthermore, the present work suggests that the change in enzymatic activity might be related to modifications in membrane fluidity.

Adolescent

Influence of environmental iodine deficiency on neonatal thyroid screening results.

During a multicentric pilot screening program for congenital hypothyroidism a comparison between the results obtained from Urbino, an area characterized by low iodine supply and endemic goiter, and Rome, a non-endemic area, has been made. The evaluation of neonatal urinary iodine excretion in the two areas showed significantly lower iodine urinary excretion levels in Urbino than in Rome. A shift of TSH at screening toward higher values as well as a higher percentage of recall in Urbino area than in Rome was observed. This finding, which well correlates with a low environmental iodine supply, emphasizes the importance of screening for congenital hypothyroidism as a suitable index of the presence and action of goitrogenic factors in the environment.

Child, Preschool

Isolation and characterization of "Methanosphaera cuniculi" sp. nov.

A nonmotile, gram-positive, spherical organism was isolated from the intestinal tracts of rabbits. Both hydrogen and methanol were required for growth. No methane was produced from hydrogen-carbon dioxide, formate, acetate, methylamines, ethanol, or isopropanol. The optimum pH was 6.8, and the optimum temperature was 35 to 40 degrees C. The DNA G+C content is 23 mol%. The pseudomurein cell wall contained serine. These characteristics and the immunological fingerprinting results are consistent with its placement in the genus Methanosphaera as a new species.

Animals

[Relation between hypoxia and thyroid function].

In view of the preponderant role of thyroid hormone in the regulation of oxygen consumption it is easy to understand the interest that has always been aroused by the study of the relationships between thyroid function and hypoxia. Thus far the results obtained have often been contrasting, demonstrating now an increase, now a reduction in thyroid function as evidenced by variations in the thyroid function parameters investigated (T3, T4, TSH, PBI), Thyroscintigraphy, captation curves, histological studies on thyroid tissue). Results obtained by various workers on the basis of physiopathology studies of altitude sickness (Bert, 1879; Mosso, 1909 and Barcroft, 1925) up to the more recent studies of Cramarossa, Donati and Bramati (1965), Moncloa (1966) and Galton (1972) are examined. The apparent discrepancy in results obtained is explained by the heterogeneity of experimental conditions ruling in the different investigations (difference of atmospheric pressure and PAO2, temperatures, diet, stress, duration of the experiment) and the diversity of the objects involved in the experiment (various animals, humans). It is concluded that research methods should be standardised more so as to achieve a more certain, definitive evaluation of the problem.

Altitude

Polyamine levels in human semen of unfertile patients: effect of S-adenosylmethionine.

Polyamine content has been determined in the seminal plasma of unfertile men before and after S-adenosylmethionine treatment. Spermine and spermidine levels in azoospermic patients were found very low (80 and 24 microgram/ml) with respect to normospermic (1500 and 60 microgram/ml): S-adenosylmethionine treatment enhanced polyamine content (50-300%) in oligospermic patients. Furthermore, an increase of sperm count and motility has been observed in these patients.

Humans