Biomedical subjects

L De Marinis

Publications and source records attributed to L De Marinis.

At least 19 recordsLinked to original sources

PubMed1992

Influence of pyridostigmine on growth hormone (GH) response to GH-releasing hormone pre- and postprandially in normal and obese subjects.

The effect of pyridostigmine (PYR), an inhibitor of acetylcholinesterase, on the GH response to GH-releasing hormone (GHRH) before and after a meal was studied in 14 normal subjects (8 females and 6 males) and 21 obese subjects (13 females and 8 males). In normal subjects tested in a fasting state, PYR was capable of stimulating GH secretion and increasing the GH response to GHRH. These effects were not apparent after food, suggesting a reduction in cholinergic hypothalamic activity. In obese subjects tested in a fasting state, PYR was ineffective when administered alone. On the contrary, it was able to increase the GH response to GHRH. After food, the augmenting effect of PYR on the GH response to GHRH was not observed, whereas a delayed inhibition of the GH response was found after PYR plus GHRH treatment. Our findings support the hypothesis that cholinergic hypothalamic activity plays a pivotal role in impaired GH regulation and the altered sensitivity of GH secretion to metabolic fuels in obese subjects.

Adult↗

PubMed1992

Acromegalic cardiomyopathy. Left ventricular filling and hypertrophy in active and surgically treated disease.

Myocardial hypertrophy and interstitial fibrosis are common in acromegalic hearts and may induce left ventricular (LV) dysfunction. The transmitral flow pattern was examined by pulsed-wave Doppler in 20 patients with active acromegaly and nine with acromegaly cured by pituitary microsurgery. Control groups consisted of 25 normal subjects and 13 patients with systemic hypertension. We related Doppler indices of LV filling (E and A peak velocities and E/A ratio) to the duration of acromegalic disease, the GH plasma levels and LV mass. The LV mass/BSA was significantly greater in active acromegaly (187 +/- 53 g/sq m) and systemic hypertension groups (161 +/- 48 g/sq m) than in cured acromegaly (125 +/- 35 g/sq m) and the normal control group (109 +/- 36 g/sq m) (p < 0.01 for both). No differences were found in the E peak velocity, A peak velocity, and E/A ratio in the groups with active acromegaly (E/A: 0.9 +/- 0.2), cured acromegaly (E/A: 0.9 +/- 0.3), and systemic hypertension (E/A: 0.8 +/- 0.5). An E/A ratio < 1 was found in 13 patients with active and four with cured acromegaly; (p = NS). In the active acromegaly group, the E/A ratio was related to either LV mass or the duration of disease (r:-0.45 and -0.47, respectively; p < 0.05). In the cured acromegaly group, the E/A ratio was related to the duration of disease before surgery (r:-0.70; p < 0.05) and not to LV mass (r:0.12). In conclusion, an impairment in LV filling may be present not only in the patients with active acromegaly but also in those successfully treated by surgery after a long duration of the disease, despite normal LV mass. These LV filling abnormalities may be in part determined by nonreversible myocardial changes, such as interstitial tissue fibrosis.

Acromegaly↗

PubMed1992

Calcium antagonists and hormone release. VIII. Effects of verapamil infusion on C-peptide to insulin molar ratio in normal subjects and obese subjects with normal glucose tolerance.

It is known that calcium-antagonist drugs can modify the insulin response to various secretagogues. In order to clarify whether calcium-antagonist effect was directed at the level of pancreatic insulin secretion or hepatic insulin extraction and further investigate the pathogenesis of hyperinsulinemia in obesity, an oral glucose tolerance test (OGTT) was performed in basal conditions and during a Verapamil infusion (VE, 5 mg/h x 3.5 h) in 12 normal subjects and 14 obese patients with normal glucose tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

GH response to GHRH before and after meals at different hours of the day in obese patients.

In normal subjects several factors are involved in the regulation of the GH response to GHRH, such as nutritional status, metabolic fuels and neurotransmitters. We previously have shown a paradoxical increase in the GH response to GHRH after meals in obese patients, in contrast to the blunted GH response observed after feeding in normal subjects. We have further investigated this phenomenon, studying the GH response to GHRH before and after meal at three different hours during the day in 10 obese patients, aged 18-35 yr, in comparison to that in eight normal women, aged 20-35 yr. GHRH was injected in a fasting state or 1 hr after a standard meal (800 KCal). In obese subjects, after food ingestion the peak GH response to GHRH was increased at 0900h and 1300h and was significant when the patients were tested after lunch (1300h). On the contrary, in the evening the GH response to GHRH remained unchanged, both before and after feeding. These data point to an altered sensitivity of GH secretion to metabolic signals in patients with obesity.

Adolescent↗

PubMed1991

Influence of naloxone infusion on prolactin and growth hormone response to growth hormone-releasing hormone in anorexia nervosa.

Anorexia nervosa (AN) is frequently associated with anomalies of growth hormone (GH) and prolactin (PRL) secretion. We studied the GH and PRL responses to GHRH1-44 (50 micrograms IV) and the effect of a naloxone infusion (1.6 mg/hr), started 1 hr before GHRH administration, on this response in 12 female patients with AN, aged 15-30 yr, and in seven normal women, aged 19-27 yr, during the follicular phase as controls. In AN, GHRH induced an increase in GH levels similar to that observed in normal subjects. A significant inhibition of the GH response to GHRH was observed during naloxone infusion, similar to the inhibition in normal female subjects during the follicular phase. PRL levels showed a significant increment after GHRH alone and a slight, nonsignificant, PRL increment after GHRH during naloxone infusion in AN patients. In contrast a slight PRL decrease was observed after GHRH, both before and during naloxone infusion, in the normal subjects. Our study demonstrates that endogenous opioids play a role in influencing PRL secretion in patients with AN different from their role in normal subjects.

Adolescent↗

PubMed1991

Evaluation of dopaminergic tone in postmenopausal women: effects of piribedil on anterior pituitary hormones.

In order to evaluate the relationships between gonadal steroid hormones and central dopaminergic (DA) tone, we have administered a "weak" dopamine agonist drug (piribedil) in 12 normal women, who were postmenopausal for at least 5 yrs, and we have studied the effects on anterior pituitary hormone release. We observed a decrease of plasma PRL levels and an increase of plasma GH values with all doses (40, 60, 100 mg p.o.) of the drug employed. No consistent changes in plasma FSH, LH, ACTH and TSH were observed and no side effects were reported. These results were greatly different from those previously described in premenopausal women in whom dose-related effects were observed and were similar to those observed in normal male subjects. The differences in the response to piribedil observed in women before and after the menopause could be due to a different sexual steroid environment.

Adrenocorticotropic Hormone↗

PubMed1991

Endocrine status in patients with mammary gland diseases: correlation between steroid hormones and sex steroid binding globulin.

We have studied 131 women affected by benign or malignant breast disease, in order to explore their endocrine status. We evaluated basal concentrations of the following hormones: FSH, LH, PRL, estrone (E1), estradiol (E2), testosterone (T), androstenedione (A), DHEAS and SHBG. Basal hormone levels in these patients were not significantly different from those in normal age-matched subjects. However, in premenopausal women, 31% of patients with benign disease and 34.4% with malignant lumps exhibited an elevated FSH/LH ratio (greater than 1) and lower T levels, compared to those having a normal FSH/LH ratio. The difference in T levels was not coupled with the expected specular variations in SHBG levels. Moreover, in none of the group considered, T concentrations or E2/T were significantly correlated with SHBG levels. These data seem to suggest an altered regulation of SHBG in these patients, in whom the modulation of SHBG by circulating sexual steroids appears to be different when compared with normal subjects.

Adult↗

PubMed1991

Calcium antagonists and hormone release. VII. Effects of gallopamil infusion on insulin and C peptide release in normal subjects.

It is known that insulin release is calcium-dependent and that calcium-antagonists, blocking calcium transport across cell membranes, inhibit it, especially interfering with the second phase of insulin secretion. Gallopamil (GAL) is a new calcium-antagonist that, although structurally similar to verapamil, has more potency. It blocks slow calcium channels and fast sodium channels. Even if it has been demonstrated in vitro, there is no evidence that GAL is able to impair the glucose-induced insulin release in humans. We have submitted five normal subjects (24-36 yr old) to oral glucose tolerance test (OGTT, 75 g of glucose p.o.) and OGTT plus GAL infusion test (1 mg i.v. as a bolus, followed by a 2 mg/hr infusion for 2.5 hr, starting 30 min before glucose load), in two different days, to determine the effects of GAL on insulin and C peptide release after oral glucose load. In opposite with verapamil effects, we found that GAL did not reduce the peak levels of insulin and C peptide, but the peak response was delayed and the incremental areas tended to increase during GAL infusion, so that an impairment of glucose tolerance was equally obtained. This study indicates that different calcium-antagonist drugs exert differential effects on insulin release and their action on glucose homeostasis should be kept in mind because of the large use of these drugs in cardiac patients.

Adult↗

PubMed1990

Association of Graves' disease and prekallikrein congenital deficiency in a patient belonging to the first CRM+ prekallikrein-deficient Italian family.

Severe prekallikrein (Fletcher factor) deficiency was diagnosed in a 49-year-old woman and in 3 of her siblings. Functional prekallikrein (PKK) activity was found below 1% by clotting assay and 20% by amidolytic assay in all the affected subjects; PKK cross-reacting material (CRM) was present in all the patients (antigen levels from 34% to 54%). This is the first CRM+ PKK-deficient family identified in Italy. The index patient was affected from Graves' disease: such association was previously reported in another patient with PKK congenital defect.

Cross Reactions↗

PubMed1990

[Immunogenetic and functional study of first-degree relatives of patients with type I diabetes mellitus for identifying prediabetic subjects].

Insulin dependent diabetes mellitus is an autoimmune disease with HLA-related genetic susceptibility. There is a latent phase before overt disease. During this phase islet cell antibodies (ICA) as a marker of humoral autoimmunity are detected and i.v. glucose tolerance test (IVGTT) is decreased. The aim of our work was to correlate IVGTT, HLA typing and ICA testing in all siblings of IDDM patients in order to identify high risk subjects (HRS). IVGTT showed significantly lower insulin levels in siblings vs controls (P less than 0.0001). This phenomenon could be caused by HLA unrelated genetic predisposition to low insulin secretion. Insulin level values of ICA+ siblings were lower than those of ICA- siblings, even if the difference was not significant.

Autoantibodies↗

PubMed1990

Prolactin-secreting adenomas--surgical results.

The long-term follow-up of the transsphenoidal microsurgical treatment in 119 consecutively operated women with a PRL-secreting adenoma is presented. An apparent total removal of the tumor was achieved in 98 cases with an enclosed tumor (58 grade 1 and 40 grade II). In the remaining cases the removal was considered partial. The achievement of persistent normal PRL basal levels was verified in 61 patients (44 grade I and 17 grade II) who had an apparent total removal of the adenoma. In the 37 remaining patients who were thought at surgery to have had total removal we have distinguished two groups: 30 patients showed a "relapse" or "persistence" of PRL levels below 200 ng/ml without clinical and radiological signs of tumor regrowth, and 7 patients with a PRL level higher than 200 ng/ml who had evidence of PRL-secreting tumor recurrence.

Adolescent↗

PubMed1990

Cerebrospinal fluid pressure and prolactin in empty sella syndrome.

In 58 female patients with the primary empty sella (PES) syndrome, a study of the CSF dynamics was done by evaluating both the absorptive reserve by a lumbar infusion test at constant rate, and/or the ICP increase occurring during REM phase of nocturnal physiological sleep. In 33, prolactin (PRL) dynamics were also investigated evaluating both the response to sequential stimulating test with thyrotropin-releasing hormone (TRH) and metoclopramide (MCP) and/or the circadian variation of PRL levels. Impairment of CSF dynamics was found in the 84% who had a hormonal pattern characterized by an increase of the PRL response to TRH and MCP and a decrease of the PRL circadian variation. Twenty-one patients with impaired CSF dynamics underwent CSF shunting procedures with disappearance of the signs of intracranial hypertension. They also had restoration of normal PRL dynamics but the endocrine alterations improved only moderately. Altered CSF dynamics play a role in the pathogenesis of the PES syndrome. A correlation between elevated ICP and the hypothalamo-hypophyseal control of PRL secretion may exist.

Adult↗

PubMed1990

Periovulatory plasma prolactin response to gonadotropin-releasing hormone: role of endogenous opiates.

It has been previously shown that in normal women during the periovulatory period, prolactin (PRL) levels increase after the administration of nonspecific stimuli, such as growth hormone-releasing hormone or gonadotropin-releasing hormone (GnRH). In order to gain insight into the mechanism of this response, we have tested the effect of a naloxone infusion (1.6 mg/h) on the PRL response to GnRH in 5 normal females, aged 20-27 years, tested during the periovulatory period. Naloxone was administered starting 60 min before GnRH administration (100 micrograms as an i.v. bolus). Naloxone clearly blunted the PRL response (basal 10.7 +/- 1.7 ng/ml, peak 11.8 +/- 0.2 ng/ml at 30 min, versus: basal 9.0 +/- 0.5 ng/ml, peak 20.6 +/- 3.9 ng/ml at 45 min after GnRH alone; significance of difference between peaks: p less than 0.05). A secondary late increase of PRL levels was observed, reaching about 60% of basal levels at 120 min (16.8 +/- 2.6 ng/ml). These data indicate that periovulatory PRL dynamics are altered by naloxone administration and suggest a possible involvement of opioid peptides in the 'paradoxical' PRL response to GnRH in normal subjects.

Adult↗

PubMed1990

Paradoxical growth hormone response to thyrotropin-releasing hormone in acromegaly. Clinical correlations and prognostic value.

We have investigated the effect of TRH on the release of GH in 20 acromegalic patients (14 females and 6 males) before and after selective removal of a pituitary tumour via transsphenoidal route. The follow-up period was 8 years. Pre-operatively the paradoxical response was present in 15 patients (75%). Mean GH values in TRH responders were significantly lower than in non-responders. According to the size and expansion diffusion of the adenoma, the patients were divided into 3 classes. The percentage of paradoxical response in patients in class III was significantly lower than in the other two classes. Postoperatively, mean GH values in pre-operative TRH responders were significantly lower than in non-responders; among 15 responders, 13 (86%) had postoperative GH levels under 5 micrograms/l; among 5 non-responders only 2 (40%) had GH values under 5 micrograms/l. Postoperatively 8 patients still had GH responsiveness to TRH: 6 with GH levels persistently (follow-up 8 years) under 5 micrograms/l and 2 with elevated GH values. The other 7 patients, who were responders pre-operatively and non-responders postoperatively, persistently exhibited low GH levels, except one subject who showed an increase in GH levels with reappearance of the paradoxical response, two years after surgery. These results suggest: 1. the paradoxical response may be expressed only when the hypothalamus-pituitary interactions are intact; 2. the disappearance of the paradoxical response cannot surely suggest a remission, and 3. the presence of a pre-operative paradoxical response is a good prognostic feature.

Acromegaly↗

PubMed1990

[The role of autoimmune mechanisms in the hyperthyroidism-viral hepatitis syndrome: a possible noncausal association. A review of the literature and the authors' own cases].

Several patients with both Basedow-Graves' hyperthyroidism and viral hepatitis were observed and it was hypothesised that this association could be explained by the individual genetic pattern in which an immunological fragility conditioned a predisposition to autoimmune diseases. This paper reports on the cases observed, the patients' histocompatibility antigen profile and the experimental data found in the literature on autoimmune involvement in the two diseases, whose association may not be coincidental.

Antibody Formation↗

PubMed1989

Evaluation of metabolic status in amiodarone-induced thyroid disorders: plasma coenzyme Q10 determination.

In previous works we have demonstrated that Coenzyme Q10 (CoQ10) levels have a significant inverse correlation with thyroid hormone concentration in patients with spontaneous hyper- or hypothyroidism. In order to verify whether this correlation is maintained in patients on long-term amiodarone therapy, in whom thyroid metabolism is altered by the iodine contained in the drug, we have studied 30 patients with thyroid dysfunction induced by chronic amiodarone treatment. We have distinguished four groups of patients: group A (n = 8): patients with true hyperthyroidism induced by drug administration; group B (n = 11): patients with mild hyperthyroid symptoms, but isolated thyroxine increase or dissociation between different indexes of thyroid function; group C (n = 5): patients with normal thyroid hormone levels, but increased TSH levels; group D (n = 6): patients who appeared really clinically euthyroid, with normal thyroid hormone levels and normal TSH response to TRH. In group A patients, plasma CoQ10 levels averaged 0.49 +/- 0.03 micrograms/ml, significantly lower than those in normal subjects and similar to those observed in spontaneous hyperthyroid patients. In group B patients, CoQ10 levels were in the normal range (0.88 +/- 0.10 microgram/ml). In group C patients, CoQ10 levels were lower than those in normal subjects and similar to those of group A patients (0.49 +/- 0.04 microgram/ml); they differed, in regards to CoQ10 values, in comparison with spontaneous primary hypothyroid patients, who had very high levels of plasma CoQ10. Finally, in group D patients, CoQ10 levels were in the normal range (0.77 +/- 0.04 microgram/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Periovulatory plasma prolactin response to synthetic growth hormone-releasing hormone in normal women.

Following the demonstration of a positive prolactin (PRL) response to growth hormone-releasing hormone (GHRH) in acromegalic and anorexic women, we have injected GHRH (50 micrograms intravenously as a bolus) in normal women during various phases of their menstrual cycle in order to establish whether a positive response was present also in normal subjects. Synthetic GHRH 1-44 elicited a significant increase in circulating PRL levels in eight women studied during the periovulatory phase of the menstrual cycle. In contrast, no significant changes in circulating PRL levels after GHRH administration were found in nine women during the midfollicular phase or in five women during the midluteal phase. A temporal correlation between the midcycle gonadotropin peak and the positive response to GHRH has been observed. Synthetic GHRH elicited the expected increase in GH levels during all phases of the cycle studied. Our data demonstrate that GHRH is capable of stimulating a PRL response in normal subjects and raise the possibility that PRL secretion is regulated by several hormones of hypothalamic origin.

Adult↗

PubMed1989

Corticotropin-releasing hormone inhibition of gonadotropin secretion during the menstrual cycle.

To determine whether corticotropin-releasing hormone (CRH) exerts an inhibitory action on gonadotropin secretion in normal fertile women, the effects of CRH on luteinizing hormone (LH), follicle-stimulating hormone (FSH), and cortisol secretion were studied during the menstrual cycle. CRH had no effect on LH release during the midfollicular phase of the cycle. By contrast, IV injection of 100 micrograms CRH elicited significant decreases in LH concentrations during late follicular (-50%) and midluteal (-52%) phases of the cycle. LH concentrations decreased during the four-hours following injection of CRH and returned to those observed during the control period five hours after injection. Similarly, CRH elicited a significant decrease in FSH secretion during the midluteal phase of the cycle. CRH injection induced an increase in cortisol release during all phases of the cycle. These data demonstrate that exogenous CRH administration results in inhibition of gonadotropin secretion in late follicular and midluteal phases of the cycle. These results suggest that elevated endogenous CRH levels resulting in increased cortisol secretion could contribute to decreased gonadotropin secretion and, thus, disruption of reproductive function during stressful conditions in women.

Adult↗