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Biomedical subjects

L Mazzanti

Publications and source records attributed to L Mazzanti.

At least 127 records · Page 7Linked to original sources
PubMed1989

Growth and sport.

In order to investigate sport's influence on growth during puberty, we examined 398 boys 10-16 yr old. 192 of these subjects had been playing football as a competitive sport, and 206 were considered as controls, having never practised sports regularly. Both groups were divided into prepubertal (with testicular volume less than or equal to 2.5 cc) and pubertal, with the latter further divided into the following chronological and bone age groups: 10-11.99, 12-13.99, 14-16 yr. In these subjects we evaluated auxological-anthropometric and biological maturity characteristics and endocrine parameters (cortisol, dehydroepiandrosterone sulphate, testosterone). No significant difference was found between prepubertal athletes and controls concerning anthropometric and biological maturation parameters, whereas testosterone basal levels were significantly lower (p less than 0.05) and DHEAS values were significantly higher (p less than 0.05). Pubertal football players were significantly taller than controls (particularly at 14-16 yr chronological age), with a greater biacromial diameter after 12 yr chronological and bone age and thinner skinfolds at 12-13.99 chronological and bone age. They were more advanced in all biological maturation parameters i.e. pubic hair, testicular volume and bone age, particularly those subjects playing football for the greatest number of years and training time. In pubertal football players the increase in DHEAS (p less than 0.05) already seen in prepubertals is also combined with a significant increase in testosterone (p less than 0.0001) and cortisol (p less than 0.05). Thus football players DHEAS is already higher during prepuberty and this increase chronologically precedes the advance in all the auxological-maturative parameters typical of our pubertal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Differences in carbohydrate tolerance in Turner syndrome depending on age and karyotype.

Carbohydrate homeostasis was evaluated in 47 girls with Turner syndrome and in 25 "short normal" girls by means of an oral glucose tolerance test. Of the Turner patients 34% showed an impaired glucose tolerance vs 8% of the controls (chi 2 = 5.9, P less than 0.05). Mean glucose levels were significantly higher and mean insulin levels and insulinogenic index significantly lower in young Turner patients aged 5-12 years but not in adolescents aged 12-16 years. In both groups of patients, insulin levels and the insulinogenic index were significantly lower than those of the controls. In Turner patients between 12 and 16 years, carbohydrate tolerance improved and this may be explained by the lack of oestrogen release in these patients. Glucose tolerance was normal in patients with mosaicism. We conclude that (1) carbohydrate tolerance is defective in young children with Turner syndrome but improves in puberty due to the almost complete absence of oestrogen-progestogen secretion; (2) a difference in carbohydrate tolerance is evident depending on karyotype.

Adolescent↗
PubMed1988

Abnormal membrane cation transport in pregnancy-induced hypertension.

An abnormality of sodium handling has been suggested as one of the mechanisms responsible for the development of pregnancy-induced hypertension. We analysed the plasma and urinary concentrations, and the intraerythrocyte activities of Na and K, and the RBC membrane Na+/K+-ATPase activity of 77 hypertensive and 133 normal pregnant women. Umbilical cord blood of infants from 21 hypertensive and 28 control women was studied. The Na+/K+-ATPase activity was determined by measuring the inorganic phosphate released by incubation in a reaction medium in the presence and absence of K ions or ouabain. The intra-erythrocyte sodium and potassium activities were measured by ion-selective electrode analysis of the haemolysates, after washing the RBCs in 110 mmol/l MgCl2. We found a significant increase in intracellular sodium and a reduction in Na+/K+-ATPase activity in the hypertensive women in comparison with the control subjects during pregnancy. No difference was observed in early puerperium. Cord blood from infants of pregnancy-induced hypertensive women showed an increase in intracellular Na+ activity and a decrease in the erythrocyte membrane Na+/K+-ATPase activity in comparison with cord blood samples from control subjects. The observed abnormalities in the plasma membrane sodium transport may play a major role in the pathophysiology of pregnancy-induced hypertension.

Biological Transport↗
PubMed1988

Abnormal membrane fluidity and acetylcholinesterase activity in erythrocytes from insulin-dependent diabetic patients.

An alteration in the enzymatic properties of the erythrocyte membrane acetylcholinesterase (AchE) and Na+,K+-ATPase has been described in experimental diabetes mellitus. We studied erythrocyte membrane fluidity and AchE and Na+,K+-ATPase activities in 15 insulin-dependent diabetic patients and 11 normal subjects. Fluidity was assessed by fluorescence polarization, using 1,6-diphenyl-1,3,5-hexatriene as a probe, and AchE and Na+,K+-ATPase activities were measured enzymatically. We found a significant increase in the enzymatic activity of AchE and a change in its enzymatic properties in diabetic patients compared with those in normal subjects. AchE activity correlated inversely with membrane fluorescence polarization, which was decreased in the diabetic patients, indicating an increase in membrane fluidity. Na+,K+-ATPase activity was reduced in the diabetic patients and correlated positively with the fluorescence polarization values. We hypothesize that the abnormal dynamic properties of the erythrocyte membrane may play a major role in determining the described change in enzymatic activity.

Acetylcholinesterase↗
PubMed1988

Sodium/potassium-adenosine triphosphatase on erythrocyte ghosts from pregnant women and its relationship to pregnancy-induced hypertension.

The regulation of electrolytes has been proposed as a possible determinant in hypertensive conditions, including pregnancy-induced hypertension. We report a study of sodium/potassium-adenosine triphosphatase in erythrocyte membranes of 59 patients with pregnancy-induced hypertension and 48 normotensive pregnant controls. The kinetics of the enzyme were also investigated, and the enzyme activity related to different degrees of pathology. A marked reduction of the enzyme activity was found in hypertensive patients, compared with controls. This reduction was greater when hypertension was associated with worse prognostic signs, such as proteinuria. These features are in agreement with the increased sodium content and the increased vascular reactivity found in pregnancy-induced hypertension. The enzyme activity appears to be decreased by means of a conformational modification of the enzyme sites, a phenomenon related to the hypertensive condition.

Edema↗
PubMed1988

Heart disease in Turner's syndrome.

Fifty-five consecutive patients with Turner's syndrome and different karyotypes underwent full cardiological evaluation (physical examination, electrocardiogram, chest X-ray and echocardiogram). Congenital heart disease was found in 17%. When compared with the general population, a significantly higher incidence was present only for aortic coarctation and partial anomalous pulmonary venous drainage (p less than 0.001). Among cardiac anomalies in Turner's syndrome patients, aortic malformations (aortic coarctation, aortic stenosis, bicuspid aorta) are the most frequent, followed by partial anomalous pulmonary venous drainage, the incidence of which has been much higher than that previously reported. We have observed that the most severe malformations are preferably found in 45,X, while the ring pattern is characterized by a very high incidence of bicuspid aorta. No anomaly was found in the patients with X isochromosome.

Adolescent↗
PubMed1988

Effect of general anesthesia on syncytiotrophoblast plasma membranes from human placenta.

This investigation shows that a general anesthetic produces similar effects in vivo and in vitro. Anesthesia with a barbituric drug, Thiopental, induces an increase in membrane fluidity and a decrease in the activity of acetylcholinesterase in syncytiotrophoblast plasma membranes (SPM) obtained from placentas after caesarean section. The same effects can be reproduced in vitro after anesthetic addition to the isolated plasma membranes. Morphological and freeze-fracturing studies also suggest that membrane protein components are affected by anesthetics.

Acetylcholinesterase↗
PubMed1988

Aclacinomycin tissue distribution in the rat.

This study was undertaken to investigate aclacinomycin distribution in the rat, using a method based on the histofluorescence of tissues treated in vivo with anthracyclines. The target organs were the kidney, lung and pancreas; a fainter fluorescence was also detected in the heart compared with adriamycin due to a quantitatively different fixing of the two anthracyclines. Our findings revealed a preferential uptake into the cell nucleus in all tissues examined except the adrenal gland medulla where a slight fluorescence appeared only in the cytoplasm.

Aclarubicin↗
PubMed1987

Growth and growth factors in diabetes mellitus.

Growth of 79 children with diabetes was analysed at diagnosis and again after one to 10.7 years of treatment with insulin. Both sexes were tall at onset, whereas at the last observation boys alone showed significant growth retardation. Height standard deviation score (SDS), however, showed no significant fall either in 32 subjects reassessed after five years of disease or in 18 subjects examined at full stature. Skeletal maturity was not significantly impaired after treatment. Pubertal growth spurt was reduced, especially in girls and in subjects with onset of disease at or around puberty. We found no significant correlation between height and height velocity SDS and glycosylated haemoglobin values or secretion of growth hormone during the arginine test. Somatomedin C values were correlated with height velocity SDS in prepubertal boys. The results of this study suggest that there are interferences in the growth of children with diabetes but that they do not seem to have a significant influence on adult height.

Adolescent↗
PubMed1986

Effects of ketamine anesthesia on rat-brain membranes: fluidity changes and kinetics of acetylcholinesterase.

This investigation shows that the effects of general anesthetics previously observed in vitro on membrane fluidity and on enzymic activities and occurring at concentrations calculated to be clinically relevant can be reproduced in vivo in anesthetized animals. Anesthesia with 2-chlorophenyl-2-methylaminocyclohexanone (ketamine) induces a more fluid state of rat-brain synaptic and mitochondrial membranes, as shown by the rotational correlation times of the spin labels 16-doxylstearate and 5-doxylstearate. Changes in acetylcholinesterase activity, with a decrease in Vmax and no change in the Km for acetylcholine, closely follow the fluidity increase.

Acetylcholinesterase↗
PubMed1986

The pharmacokinetic profile of clofoctol in rat plasma and tissues after oral and rectal administration.

The pharmacokinetics of clofoctol was investigated in rat plasma and tissues after both oral and rectal treatment at a single dose of 300 mg/kg. After oral administration the plasmatic peak was 2.12 +/- 0.92 microgram/ml, occurring at the 90th min, with T/2 of 121.45 +/- 23.41 min. After rectal administration a plasmatic peak of 1.97 +/- 0.61 microgram/ml was reached at the 20th min with T/2 of 41.07 +/- 12.30 min. The kinetic profile of the drug in tissues exhibited a pattern similar to that in the plasma, since the maximal peak of clofoctol in tissues following rectal administration occurred before that obtained after oral administration. Tissue concentrations significantly higher than plasmatic ones were obtained through both administration routes. The present results indicate that clofoctol is well absorbed after both oral and rectal administration; however rectal treatment produces more rapid absorption and elimination compared with oral treatment.

Animals↗