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Biomedical subjects

A Caiazza

Publications and source records attributed to A Caiazza.

At least 37 records · Page 2Linked to original sources
PubMed1992

Luteinizing hormone response to an intravenous infusion of substance P in normal men.

The effect of synthetic substance P (SP), infused intravenously in doses of 0.5, 1.0, or 1.5 pmol/kg-1/min-1 for 60 minutes, on gonadotropin secretion was evaluated in seven healthy men. SP tests and a control test with normal saline were randomly performed at weekly intervals. During the tests, SP infusion did not produce untoward side effects or changes in blood pressure. Plasma testosterone concentrations were normal in all subjects and remained unmodified during all tests, regardless of the infused dose of SP. Plasma luteinizing hormone (LH) levels were not modified when either normal saline or the lowest dose of SP were infused, whereas they were significantly increased in a dose-dependent fashion when larger amounts of SP were administered. In contrast, plasma follicle-stimulating hormone (FSH) concentrations did not change significantly during any test. These data demonstrate for the first time in normal men that the systemic infusion of SP stimulates LH release, without modifications of FSH secretion.

Adult↗
PubMed1992

Effect of potentiation of cholinergic tone by pyridostigmine on the GH response to GHRH in elderly men.

The plasma GH response to GHRH (100 micrograms i.v.) was evaluated either alone or after pretreatment with pyridostigmine (120 mg orally 1 h prior to GHRH) in 9 younger men (age range: 22-39 years) and in 9 healthy elderly men (age range: 63-77 years). On a different occasion, subjects were tested with pyridostigmine alone. Basal concentrations of glucose, cortisol, androgens, estrogens, thyroid hormones and GH were similar in all subjects, whereas insulin-like growth factor was lower in elderly men. The GH response to GHRH was significantly lower in the older (mean peak was 6 times higher than baseline) than in the younger group (mean peak was 11.3 times higher than baseline). The pretreatment with pyridostigmine induced a striking increase in the GH response to GHRH in the younger subjects (mean peak was 26 times higher than baseline), whereas it produced only a slight increase in the GHRH-induced GH response in elderly men (mean peak was 8.7 times higher than baseline). When pyridostigmine was given alone, plasma GH levels rose significantly in both groups; however, the pyridostigmine-stimulated GH response was significantly higher in younger (mean peak was 6 times higher than baseline) than in older subjects (mean peak was 2.5 times higher than baseline). These data indicate that the cholinergic stimulatory regulation of GH release is reduced in elderly subjects. Since acetylcholine inhibits hypothalamic somatostatin release, the reduced cholinergic tone in elderly subjects may result in an increased somatostatinergic tone.

Adult↗
PubMed1991

Oxytocin does not modify the prolactin response to metoclopramide in normal women.

The present study was undertaken in order to establish whether oxytocin (OT) affects the dopaminergic control of PRL secretion in normal women during follicular, periovulatory and luteal phase of their menstrual cycle. For this purpose, 22 normal women were tested with a lower (1 mg) or higher (10 mg) dose of the dopaminergic antagonist metoclopramide (MCP) with or without the concurrent treatment with OT (2 IU injected plus 0.033 IU/min infused for 2 h). Since OT was found unable to modify the effect of either 1 or 10 mg MCP, in additional experiments the same doses of MCP and OT were administered after dopamine (0.04 micrograms/kg/min for 2 h) infusion. Also in these experimental conditions OT failed to modify the PRL response to MCP. These data argue against a role of OT in modulation of the dopaminergic control of PRL secretion in normal women.

Adult↗
PubMed1991

Abnormal arginine vasopressin response to cigarette smoking and metoclopramide (but not to insulin-induced hypoglycemia) in elderly subjects.

Aging is known to reduce arginine vasopressin (AVP) response to volumetric stimulations and to increase AVP responses to osmotic stimuli and to administration of metoclopramide (MCP). In order to gain a better insight into the effect of age on AVP secretion, we evaluated AVP responses to cigarette smoking, MCP, and insulin-induced hypoglycemia in 30 male subjects aged 22-81 and divided into 3 groups by age. Basal AVP concentrations were similar in all groups. The AVP response during the insulin tolerance test had a similar pattern and magnitude (2.5-fold increase) in all groups. AVP responses to MCP and cigarette smoking were similar in the two younger groups, with plasma AVP levels increased 2 times by MCP and 2.5 times by cigarette smoking. In contrast, both MCP- and cigarette smoking-induced AVP rises were significantly higher in the oldest group, where plasma AVP concentrations increased 2.5 times after MCP and 3.25 times after smoking. When data of the MCP and cigarette smoking tests were combined, regression analyses showed a significant positive correlation between AVP peak responses to MCP and cigarette smoking in the oldest subjects. These data show that elderly humans have increased AVP responses not only to MCP but also to cigarette smoking, suggesting a common disorder for both alterations. In contrast, the lack of age-related changes in AVP response during the insulin tolerance test demonstrates that the mechanism underlying the AVP response to hypoglycemia is not affected by aging.

Adult↗
PubMed1991

[Endoscopic surgery of the digestive system: state of the art. Opinion of an endoscopic surgeon].

The Authors review the possible applications of surgical endoscopy in oesophageal, gastric, biliary, pancreatic and colic diseases. This critical assessment, performed under the abdominal endoscopic surgeon's point of view, is based on the overall experience of about 20 years of surgery, with particular regard to the sclerosis of oesophageal varices, neoplastic obstructions of oesophagus, biliary tract, colon and localized Laser treatment of neoplasms. Based on the results achieved, thanks to selective indications and monitoring by conventional surgical experience, the Authors conclude by staging a better reliability of the surgeon who performs surgical endoscopy to obtain good results after an accurate selection of those cases which can really benefit from endoscopic management.

Attitude of Health Personnel↗
PubMed1990

Effect of obesity and weight loss on arginine vasopressin response to metoclopramide and nicotine from cigarette smoking.

We have previously reported an impaired arginine vasopressin (AVP) response to insulin-induced hypoglycemia in obese men, suggesting a hypothalamic-posterior pituitary disorder in obesity. In the present study, we examined the AVP response to other releasing stimuli with a central site of action. The AVP response of 10 obese men to metoclopramide (MCP) or nicotine inhaled with cigarette smoking was compared with that obtained in eight sex- and age-matched controls. The AVP increase during nicotine and MCP tests were significantly lower in the obese patients than in the normal controls. Obese men were restudied after substantial weight loss. The AVP response to nicotine and MCP administration was significantly higher than before slimming and did not differ from that observed in the normal weight subjects. These results demonstrate obesity-related alterations in the AVP responsiveness to nicotine inhaled with cigarette smoking and MCP, supporting the hypothesis for a hypothalamic-posterior pituitary disorder in obesity.

Adult↗
PubMed1990

Abnormal arginine-vasopressin responses to metoclopramide and insulin-induced hypoglycemia in type I diabetes mellitus.

Alterations in the control of arginine-vasopressin (AVP) secretion have been described in type I diabetes mellitus. In order to gain a better insight into this problem, we examined whether insulin-dependent diabetics in good metabolic conditions and without diabetic complications had an abnormal AVP responsiveness to metoclopramide (MCP), an AVP-stimulating agent with a central site of action. In addition, we tested the AVP response to insulin-induced hypoglycemia in the same subjects. Twenty insulin-dependent diabetic men without neuropathy or other diabetic complications were divided into two groups according to the duration of their illness (10 patients who had been diabetic for less than 10 years, group 1, and 10 patients who had been diabetic for more than 10 years, group 2). Eleven age- and weight-matched normal men participated as controls. All groups were tested with MCP (20 mg in an intravenous bolus) and, on a different occasion, with insulin-induced (0.15 IU/kg) hypoglycemia. Experiments started after optimization of the metabolic status of the diabetic men by 3 days of treatment with continuous subcutaneous insulin infusion. Basal concentrations of AVP were similar in all groups (diabetics of group 1: 2.2 +/- 0.2 pmol/l, mean +/- SE; group 2: 2.3 +/- 0.2 pmol/l; normal controls: 2.2 +/- 0.2 pmol/l). Administration of MCP induced a striking elevation of plasma AVP levels in the normal controls and in the diabetic subjects of groups 1 and 2. All subjects showed a mean peak response at 15 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

5-HT1-, but not 5-HT2-serotonergic, M1-, M2-muscarinic cholinergic or dopaminergic receptors mediate the ACTH/cortisol response to metoclopramide in man.

The possible mediation of dopaminergic, muscarinic cholinergic and/or serotonergic receptors in the response of ACTH/cortisol to metoclopramide (MCP) was evaluated in 27 normal men. All subjects were tested with MCP (10 mg in an intravenous bolus plus placebo or saline, NaCl 0.9%, control test). For the other tests (experimental tests), the men were divided into three groups of 9 subjects each. One group was tested with MCP in the presence of the dopaminergic agonist bromocriptine (5 mg p.o. 3 h before MCP), another group was tested with MCP plus the M1- and M2-muscarinic-cholinergic antagonist atropine (1.2 mg in an intravenous bolus, just before MCP) or the M1-muscarinic receptor blocker pirenzepine (40 mg in an intravenous bolus 10 min before MCP). The third group was tested with MCP after treatment with the selective 5-HT1-serotonergic receptor blocker metergoline (10 mg/day p.o. in 5 divided doses for 4 days before MCP) or the 5-HT2-serotonergic receptor antagonist ketanserin (10 mg as a slow 3-min intravenous injection, 5 min before MCP). ACTH and cortisol rose by 45 and 55%, respectively, in response to MCP. The basal levels of ACTH and cortisol were not modified by bromocriptine, atropine, pirenzepine, metergoline or ketanserin treatment. Both ACTH and cortisol responses to MCP did not change significantly after bromocriptine, atropine, pirenzepine or ketanserin administration, whereas they were completely abolished by pretreatment with metergoline. Additional experiments were performed in order to evaluate whether the effect of metergoline on the ACTH/cortisol response to MCP depends on the amount of the serotonergic antagonist (dose-response study).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1989

Antihypertensive effect of slow-release nicardipine. A placebo-controlled cross-over study.

The magnitude and duration of the antihypertensive effect of slow-release nicardipine (SR-Nicardipine) have been compared with placebo in 36 uncomplicated essential hypertensives (diastolic BP 95 to 115 mm Hg after 1-month placebo washout). According to a double-blind, randomized, cross-over design they received SR-Nicardipine 40 mg b.d. and placebo for 1 month. At the end of each treatment period, blood pressure and heart rate were measured 12 h after the evening dose and 1, 2, 3 and 4 h after the morning dose. SR-Nicardipine significantly reduced systolic (SBP) and diastolic (DBP) blood pressure at each time after dosing. The absolute decrements peaked 4 h after dosing (-18.3 and -11.7 mm Hg, respectively) and more than 90% of the peak effect persisted 12 h after dosing, both for SBP and DBP. The heart rate was slightly increased by SR-Ni-cardipine. Adverse effects monitored with a check-list occurred in 31% of patients during SR-Nicardipine treatment and in 28% on placebo. Thus, SR-Nicardipine 40 mg b.d. has a maintained and significant antihypertensive effect lasting up to 12 h in essential hypertension.

Adult↗
PubMed1989

Dopaminergic, but not cholinergic, involvement in regulation of hypoglycemia-induced oxytocin release in man.

The plasma oxytocin response to insulin-induced hypoglycemia was evaluated in 20 normal male subjects in the basal state (insulin tolerance test (ITT) alone) and after pretreatment with the muscarinic antagonist pirenzepine (40 mg IV 10 min before the ITT in six subjects), the nicotinic antagonist trimethaphan (0.3 mg/min IV for 30 min before the ITT in six subjects), and the dopaminergic receptor agonist bromocriptine (2.5 mg PO 1 hr before the ITT in eight subjects). The drugs did not modify arterial blood pressure nor produce side effects capable of altering oxytocin secretion. Neither pirenzepine nor trimethaphan administration changed the oxytocin response to hypoglycemia, whereas bromocriptine significantly reduced the oxytocin increase during the ITT. These data suggest the involvement of dopaminergic, but not of cholinergic, muscarinic or nicotinic, receptors in the oxytocin response to hypoglycemia.

Adult↗
PubMed1989

Muscarinic cholinergic, but not serotoninergic mediation of arginine vasopressin response to metoclopramide in man.

The possibility that metoclopramide (MCP) stimulates arginine vasopressin (AVP) secretion in man through a serotoninergic and/or a cholinergic muscarinic pathway was studied. Twenty normal male subjects were tested with MCP (10 mg in an i.v. bolus) alone or in the presence of the 5HT1 serotoninergic antagonist metergoline (10 mg/day p.o. in five divided doses for 4 days), the 5HT2 receptor blocker ketanserin (10 mg i.v. 5 min before MCP) (n = 10), the M1 and M2 muscarinic antagonist atropine (1.2 mg i.v. just before MCP administration) or the M1 muscarinic receptor blocker pirenzepine (40 mg i.v. 10 min before MCP) (n = 10). AVP doubled in response to MCP. the MCP-induced AVP rise did not change after metergoline, ketanserin or pirenzepine administration, whereas it was abolished by atropine. Additional experiments were performed in order to evaluate the effect of 1.2 mg atropine, given alone, on circulating AVP levels and whether the effect of atropine on the AVP response to MCP depends on the amount of the muscarinic antagonist (dose-response study). For these purposes, atropine was given alone to the same subjects previously tested with MCP plus atropine; furthermore, eight additional male subjects were tested with MCP plus atropine given in doses ranging from 0.8 to 1.4 mg. The results of these additional studies failed to show an effect of atropine alone on AVP secretion and demonstrated a dose-related inhibition of MCP-induced AVP rise by increasing atropine administration from 0.8 mg to 1.2 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The combination of a low-Na/high-K salt with metoprolol in the treatment of mild-moderate hypertension. A multicenter study.

To extend our previous findings that a low-Na/high-K salt (S) reduces BP in hospitalized patients, a multicenter study was performed. After a placebo period during which patients were informed by written instruction how to avoid only foods with a high Na content, 143 out-patients (84 males and 59 females, mean age 50.7 years, range 28-69) with DBP greater than or equal to 95 mm Hg randomly received for 4 weeks either metoprolol (M) 200 mg SR qd (67 patients), or S, 2 g bid to add to foods (76 patients). At the end of this period patients with DBP still greater than 90 mm Hg combined the two treatments for a further 4 weeks. Mean blood pressure (mm Hg), HR (bpm), 24-hrs urinary Na and K excretion were measured fortnightly. In comparison to pretreatment values MBP was significantly (P less than 0.01) reduced by both treatments, although to a greater extent in the M group already at the second week, without any further decrement thereafter. In the S group MBP decreased by 4.4 mm Hg and 27/76 patients were responders (DBP less than or equal to 90 mm Hg), while in the M group it was reduced by 9.0 mm Hg and 28/67 patients were responders. In the S group urinary Na excretion was significantly (P less than 0.01) lower than in the M group, and this difference was present until the end of period 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Prevention of pulmonary complications by 6-methylprednisolone in major abdominal surgery.

Methylprednisolone sodium succinate (MPSS) was compared in a randomized, double blind study to placebo in the prevention of respiratory complications in patients submitted to abdominal (vascular, pancreatic or hepatic) surgery. Two out of 42 (4.8%) patients treated with MPSS and 9 patients out of 40 (22.5%) who received placebo experienced a pulmonary complication (p less than 0.05) The results indicate that methylprednisolone could prevent the onset of respiratory complications in patients undergoing major abdominal surgery.

Abdomen↗
PubMed1987

Lysine-vasopressin does not affect basal and LH-RH-stimulated LH and FSH release during the menstrual cycle of normal women.

In order to test possible effects of lysine-vasopressin (LVP) on basal and LH-RH-stimulated LH and FSH release, an intravenous bolus of LVP (0.06 IU/kg body weight) was injected alone or 10 min before LH-RH (100 micrograms i.v.) in 33 normal women in the follicular, periovulatory and luteal phase of their menstrual cycle. The administration of LVP modified neither the basal secretion of the gonadotropins nor the LH-RH-induced LH and FSH release. These data suggest that in humans, vasopressin is not involved in the control of gonadotropin release at the level of the anterior pituitary.

Adult↗