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Biomedical subjects

R Mauri

Publications and source records attributed to R Mauri.

At least 19 recordsLinked to original sources
PubMed1991

[Serology study for HBV and HIV-1 in a cohort of parenteral drug addicts].

We studied 335 subjects, all drug addicts for the presence of the following serological markers: HIV1 antibody, HBsAg, HBsAb, HBcAb totals. We conclude that subjects HIV1 positive (n. 149) present HBsAb in a significantly lower number (p greater than 0.001) than HIV1 negative subjects (n. 95). The presence of HBcAb isolated is significantly higher (p greater than 0.001) in subjects HIV1 positive. They show an altered serological response to HBV compared to subjects HIV1 negative.

Adolescent↗
PubMed1988

The pineal gland-opioid system relation: melatonin-naloxone interactions in regulating GH and LH releases in man.

Several observations have demonstrated that the opioid system can modulate melatonin secretion from the pineal gland and that the effects of opioids may require a pineal participation. In contrast, the role played by the pineal gland in regulating the synthesis and secretion of endorphins and enkephalins in still obscure. To establish whether the neuroendocrine activity of melatonin are mediated by endogenous opioids and to demonstrate a possible action exerted by the pineal gland on opioid peptides, GH and LH serum mean levels were evaluated by RIA in 12 healthy subjects of both sexes after melatonin injection alone (0.4 mg/kg bw im at 09:00 h) and on a separate occasion after a simultaneous administration of melatonin and naloxone (1.2 mg iv as a bolus, followed by an iv infusion of 1.6 mg/h for 3h). On an other occasion, the study was performed during saline or naloxone infusion alone. In each test, venous blood samples were collected at -20, 0, 30, 60, 90, 120 and 180 min. A significant rise of GH was observed after melatonin injection alone. The simultaneous infusion of naloxone blocked melatonin-induced GH rise. Melatonin did not affected LH serum levels, while it was able to reduce LH increase induced by naloxone. These preliminary results suggest that some neuroendocrine effects of melatonin might be mediated by a modulation on the opioid tone.

Adult↗
PubMed1987

The clinical significance of melatonin serum determination in oncological patients and its correlations with GH and PRL blood levels.

In order to investigate the pineal function and its relation with the hypophysis in human neoplasms, melatonin and GH serum levels were determined in 63 patients, 42 affected by solid tumours and 21 by lymphoma or leukaemia. In women with breast cancer PRL was also measured. Melatonin, GH and PRL were evaluated in 52 healthy subjects acting as controls. The oncological patients showed significantly higher mean melatonin serum levels than the control subjects. Mean melatonin values were lower in patients with solid tumours who had metastases, than in cases without metastases. Chemotherapy caused an evident decrease in melatonin levels. Surgery was followed by a fall in melatonin in patients without metastases. Mean GH serum levels observed in oncological patients were similar to those in control subjects and were not influenced by therapy. PRL levels were within the normal range in women suffering from breast cancer.

Adolescent↗
PubMed1986

A clinical study of the pineal gland activity in oncologic patients.

It has been known for many years that the pineal gland is involved in regulating tumor growth. In order to evaluate the functional activity of the pineal gland in neoplastic diseases, melatonin serum levels and its light/dark rhythm have been determined with the RIA method in patients affected by various forms of tumor. Irrespectively of the type of the tumor and of its localization, existence of two subpopulations has been observed within the oncologic patients, the former with normal levels of melatonin, and the latter with high ones. The light/dark rhythm of melatonin was anomalous in some cases. An evident decrease of serum melatonin values was seen after chemotherapy. It might be interesting to establish whether melatonin levels may conditionate the prognosis of patients with cancer.

Adolescent↗
PubMed1986

A clinical study on the relationship between the pineal gland and the opioid system.

Recent reports point to a link between the pineal gland and the opioid system. In order to investigate this relationship, two separate studies were performed on humans. Beta-endorphin plasma levels were determined after melatonin administration (0.2 mg/kg b.w. i.m. at 2 p.m.). Melatonin serum values were evaluated after administration of FK 33-824, a met-enkephalin analogue (0.3 mg i.v. infusion at 9 a.m.). A significant decrease of beta-endorphin plasma levels was observed 120 minutes after melatonin injection. Melatonin release was stimulated by FK 33-824, with a peak at 30 minutes. The present results provide evidence of the inhibitory effect of melatonin on beta-endorphin secretion and the stimulatory action of the opioid peptides on the pineal gland. However, further studies will be required to clarify the relationship between the opioid system and the pineal gland.

Adolescent↗
PubMed1986

Growth hormone and somatomedin-C response to synthetic human pancreatic tumor GH-releasing factor in hypopituitary and constitutionally short children.

GH and somatomedin-C response to acute hpGRF-44 iv administration (1 microgram/Kg bw) was studied in 16 patients with hypopituitarism (GHD) and in 7 constitutionally short subjects. GH-deficient patients evidenced a significant GH increase peaking between 15 and 60 min. (4.95 +/- 0.88 ng/ml, mean +/- SE) (p less than 0.01 vs placebo). In non GH-deficient subjects GH increase was more pronounced (peak 18.00 +/- 3.01 ng/ml; p less than 0.01 vs both placebo and GHD group). Acid-extractable somatomedin-C was slightly, but significantly higher than baseline at 12th h (p less than 0.01) in both patients with hypopituitarism (basal value: 0.067 +/- 0.021 U/ml; 12 h: 0.096 +/- 0.024 U/ml) and constitutionally short subjects (basal value 0.62 +/- 0.13; 12h 0.72 +/- 0.16 U/ml). In 3 subjects with hypopituitarism multiple iv administrations (1 microgram/kg bw at 09:30 and 21:30 h for 4 days) produced on the average a modest increase of the GH responsiveness, were more effective to enhance somatomedin-C concentration, but not sufficient to reach normal levels. Sc administration of the same dose at 4-h intervals by a programmable portable pump - performed on 6 GHD subjects - produced an increase of GH peak response on the 4th day of treatment (1.38 +/- 0.31 ng/ml) with respect to the one observed on the first day (0.42 +/- 0.09 ng/ml). Somatomedin-C increase was low and inconstant. These data support the use of a 4-5-day pulsatile treatment in the differentiation between hypothalamic and pituitary deficiency, and the possibility of therapeutical use of GRF with the same protocol when a response is evidenced.

Adolescent↗
PubMed1986

Effect of an acute injection of melatonin on the basal secretion of hypophyseal hormones in prepubertal and pubertal healthy subjects.

It is well known that the pineal gland can modulate the secretion of pituitary hormones. Melatonin, the main hormone produced by the pineal gland, acts at the hypothalamic site, whereas hypophyseal sensitivity to melatonin seems to change with age. To investigate the influence of pubertal development on the role of the pineal gland in the regulation of the secretion of pituitary hormones, FSH, LH, Prl, TSH and GH responses to melatonin were evaluated in a group of 9 prepubertal and 10 pubertal healthy subjects of both sexes. Melatonin was given im at a dose of 0.2 mg/kg body weight at 3 p.m. Venous blood samples were drawn -20, 0, 20, 40, 60, 90, 120, 180 and 240 min, after melatonin injection. According to the same experimental protocol, venous blood samples were collected during a saline infusion on a separate occasion. FSH, LH, Prl, TSH and GH plasma levels were measured with RIA. In pubertal subjects, a significant rise in the mean Prl levels was seen 90 min after melatonin as compared with those during saline infusion. The Prl melatonin response area was significantly lower in prepubertal treated subjects and significantly higher in pubertal ones compared with the respective controls. The mean GH values showed a significant decrease 120 min after melatonin only in prepubertal subjects; no significant variations were seen in 8 of 10 pubertal subjects, whereas in the last 2 a marked increase was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

[Daily secretion of parathyroid hormone in adult subjects].

Data reported in the literature on the existence of a circadian rhythm in PTH secretion are contradictory. In order to assess whether haematic PTH levels vary over a 24 hour period, the plasma levels of the hormone were evaluated at 6 different times during the day (12, 19, 24, 2, 4, 6 hours) in a group of 10 healthy adults (5 males, 5 females), aged from 24.8 to 48.7 years. PTH values were determined by the double antibody radioimmunological method using commercially available kits (PTH-K Sorin-Saluggia), whose antiserum reacts with C terminal fraction of the hormone. No statistically significant differences were observed, either between the sexes or among the samples collected during the 24 hour period. The results therefore seem to preclude the existence of a circadian rhythm in PTH secretion. However, further studies and more data - based on RIA methods, whose antiserum reacts with the N terminal of the hormone - would be necessary to preclude the existence of rapid circadian variations in PTH over the 24 hour period.

Adult↗
PubMed1985

Effects of melatonin on PRL secretion during different photoperiods of the day in prepubertal and pubertal healthy subjects.

The effect of melatonin on PRL secretion has not been established yet. In an attempt to establish whether PRL response to melatonin changes in relation to the photoperiods of the day and pubertal maturation, we evaluated PRL plasma levels after melatonin administration in 19 prepubertal and pubertal healthy subjects of both sexes in two different periods of the day: in the morning, when the sensitivity to melatonin is low, and in the afternoon, when the responsiveness to melatonin is higher. Melatonin was given im at a dose of 0.2 mg/kg BW PRL plasma levels were determined with double antibody RIA method. When melatonin was administered in the morning, all pubertal subjects and 7 of 9 prepubertal ones showed no significant variation of PRL levels; a significant decrease was observed in the other 2 prepubertal subjects. On the contrary, when melatonin was given in the afternoon, a significant increase in PRL plasma levels was seen in all pubertal subjects; no significant changes were found in 6 prepubertal ones, while in the other 3 a marked decrease could be observed. The results reveal that the response of PRL to melatonin depends upon the times of day of administration and on pubertal development.

Adolescent↗
PubMed1984

Cirrhosis associated with multiple transfusions in thalassaemia.

The study of surgical liver biopsy specimens obtained during splenectomy in 86 children with thalassaemia indicated that such patients may develop liver disease that evolves into cirrhosis. Histological characteristics suggest that it is post-necrotic cirrhosis. Onset of cirrhosis in some patients may occur as early as 7-8 years old, and at age about 15-16 years most children with thalassaemia show features of cirrhosis. In addition to fibrosis, hepatitis, or even aggressive hepatitis may develop as has also been observed in patients without thalassaemia who have undergone multiple transfusions. This study presents the current probable evolution of liver disease in patients with thalassaemia and may thus serve as a reference from which to evaluate any future progress in the treatment and care of patients with Cooley's disease.

Adolescent↗
PubMed1982

Haemoglobin levels and blood requirement in thalassaemia.

The relationship between blood requirement and the mean level of maintained haemoglobin was examined in 392 patients with homozygous beta-thalassaemia. Pre- and post-transfusional haemoglobin levels and the amounts of blood transfused were measured during a 1-year period. No significant differences were noted in the blood requirements of patients (splenectomised or not) irrespective of the haemoglobin level. It may be supposed that if the mean haemoglobin level is high the haematopoietic activity is inhibited, and hence the bone marrow mass and total blood volume are reduced. High haemoglobin levels may thus be obtained with no increase in blood intake.

Adolescent↗