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R Giorgino

Publications and source records attributed to R Giorgino.

136 records · Page 8Linked to original sources
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[Individual characteristics and biological rhythms. VI. Circadian variations of body temperature].

It has been reported that body temperature fluctuates differently in evening and morning type subjects. In order to assess this finding in 779 university students the body temperature has been measured between 1986 and 1989. Body temperature exhibits circadian rhythm in 78.6% of subjects, but no differences between morning and evening type crest phases were found. Since this result contradicts literature data, the finding is discussed also on the basis of the difference of the percentage between our grouping and that of the other authors. Further studies are in progress in order to detect if the subjects of the two groups differ for other biological and psychological parameters as well.

Adult↗
PubMedDate not supplied

[Adenylate cyclase response to beta-adrenergic agonists in heart and brown adipose tissue].

Some sympathomimetic compounds (i.e. BRL37344) increase brown adipose tissue (BAT) thermogenesis with minimal cardiac effects. They act through an "atypical" beta-adrenergic receptor (beta-AR). Since beta-AR responses involve Adenylate Cyclase (AC) activation, we investigate the AC answer to isoproterenol and BRL37344 in rat plasmamembranes of heart (beta 1-ARs) and BAT (atypical beta-ARs). AC dose-response curves were obtained by incubating membrane fractions with different concentrations of isoproterenol and BRL37344 (1 nM-100 microM) at 25 degrees C for 15 min. In our study BRL37344 is 40-times more potent than isoproterenol in stimulating AC activity of BAT (EC50s: BRL37344 = 0.02 microM, isoproterenol = 0.7 microM). Furthermore it is more potent in stimulating BAT AC than heart AC (BRL37344 EC50 ratio heart/BAT = 38). However on BAT membranes, BRL37344 intrinsic sympathomimetic activity (ISA) vs. Isoproterenol is 0.87. Since isoproterenol and BRL37344 show a similar ISA for BAT respiration and lipolysis, we may argue that AC maximal activity is not required for maximal lipolytic and thermogenic responses.

Adenylyl Cyclases↗
PubMedDate not supplied

[Assessment of the use of hemoglobin AIc in diabetes mellitus screening].

A population of 495 volunteer subjects who applied to the screening diabetes Centre of Hôtel-Dieu hospital in Paris has been studied and divided into two samples. In the first 300 subjects sample the sensitivity and the specificity of different fasting blood glucose threshold values, of different glycosylated hemoglobin threshold levels and of various combinations of the above mentioned parameter have been evaluated as a test for diabetes diagnosis defined by a 2-hr OGTT value greater than or equal to 200 mg/dl. The predictive values for both positive and negative diagnosis were also evaluated. The combination of a fasting blood glucose greater than or equal to 120 mg/dl with a glycosylated hemoglobin greater than 5.8% was found to be the best association with a good relative specificity (97.9%), a fair sensitivity (64.7%) and a fair predictive value for a positive diagnosis (64.7%). A second sample includes 195 subjects. These were classified according to either the above criterion or either the 2-hr OGTT value greater than or equal to 200 mg/dl. A great majority of subjects (95.4%) was classified in concordance by the two methods. The characteristics of the subjects that were identically classified as diabetic subjects (n = 5) were compared to those of differently classified subjects (n = 9). Longitudinal surveys are needed in order to assess the validity of HbA1c measurement as a tool for diabetes screening by reference to unquestionable criteria of the disease.

Adult↗
PubMedDate not supplied

Beta-adrenoceptors desensitization may modulate catecholamine induced insulin resistance in human pheochromocytoma.

Catecholamines acutely exert a pronounced insulin-antagonistic effect, which is mediated by beta-adrenergic receptors stimulation. Nevertheless, several patients with pheochromocytoma fail to exhibit an overt diabetic syndrome, in spite of steadily elevated plasma levels of catecholamines. This prompted us to investigate a 16 years old male patient, bearing an extra-adrenal pheochromocytoma, who displayed a slightly impaired glucose tolerance to oral glucose tolerance test, whereas fasting and post-prandial blood glucose, as well as glycaemic response to intravenous glucagon, were in the normal range. Peripheral insulin sensitivity, as evaluated by intravenous insulin tolerance test, was slightly decreased. Supine norepinephrine plasma levels were steadily upon 9 ng/ml; plasma insulin, both fasting and post-prandial, was within the normal range. beta-adrenergic receptors density of peripheral mononuclear cells was strongly reduced when compared to controls (0.97 +/- 0.08 vs 2.82 +/- 0.37 fmol/10(6) cells), without any concomitant change of affinity. Insulin binding to circulating monocytes was reduced as well (2.38 +/- 0.27 vs 5.1 +/- 0.4%/10(7) monocytes); insulin receptor affinity was quite normal (1.7 ng/ml) and total receptor number was 9,200 sites/cell. In desensitization experiments, 1 microM isoproterenol caused only a 20% decrease of beta-adrenergic receptors density in the patient's cells (70% decrease in controls). Six months after surgery, all the above modifications of receptor binding, as well as the mild glucose intolerance, were almost completely reversed. Thus, high levels of norepinephrine were able to induce a decrease of both beta-adrenoceptor and insulin receptor binding, together with a marked reduction of in vitro agonist-induced redistribution of beta-adrenergic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

17-a-OH-progesterone to testosterone plasma ratios and their modification after HCG in normal men and in patients with idiopathic infertility.

We have investigated on eventual relationships existing in men between plasma levels of 17-a-OH-Progesterone (17-a-OH-P) and, plasma levels of Testosterone (T) and on the modifications of these relationships after stimulation of the testicles by HCG (Human Chorionic Gonadotropin). An inverse correlation exists between basal plasma levels of the two steroids and their delta max (%max increase 96 h after the injection of 5000 I.U. of hCG): r = -06, p 0.01. This suggests that the enzymatic steps of the delta -4 steroidogenic pathway are rate-limiting for the synthesis of T. The delta max of the two-steroids are also inversely correlated with the circulating levels of LH (Luteinizing Hormone) (r = -05, -06; p less than 0.01) suggesting that the rate-limiting activity of the delta 4 pathway is under endogenous LH control. A desensitized state of this pathway can be expected in presence of high circulating levels of LH. Similarly to LH also the FSH plasma levels, an index of function of the seminiferous tubules, are inversely correlated with the 17-a-OH-P and T delta max (r = -0.4, -05; p 0.005) indicating close relationships between tubular and interstitial functions. In men with idiopathic oligozoospermia and high circulating levels of FSH we have found increased 17-a-OH-P/T ratios after hCG.

17-alpha-Hydroxyprogesterone↗
PubMedDate not supplied

Combining three different sources as a valid tool to identify known diabetic patients: use in a prevalence study in an Italian local health unit.

This study was carried out to validate the prevalence of known diabetes estimated from three different simultaneous sources (medical records from out-patient departments, registers and pharmaceutical prescriptions) as against the diagnosis of family doctors who had received ad hoc training before the study. To this effect, a selected Local Health Unit (Unità Sanitaria Locale or USL) in Bari, southern Italy, was examined. 2917 diabetic patients were found, with a 2.82% prevalence. The prevalence of known diabetes estimated from separate sources was 1.41% from medical records, 1.52% from the registers and 1.59% from prescriptions. With reference to the family doctor's conclusions, sensitivity, positive predictive value and efficiency of medical records were 49.8%, 92.5% and 57.4% of USL registers 53.8%, 95.6% and 61.8% of prescriptions 56.3%, 71.2% and 47.9%. 46% of the diabetic subjects were only identified from one source. In conclusion, by combining several sources of information together, a higher number of diabetic patients are identified than would be done by using separate sources; also, active cooperation from the family practitioners seems to be needed to correct the large number of false positive patients (n = 798) mostly identified from prescriptions.

Diabetes Mellitus↗