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Biomedical subjects

A V Greco

Publications and source records attributed to A V Greco.

At least 145 records · Page 8Linked to original sources
PubMed1986

Electrophysiologic effects of somatostatin in man.

Experimental and clinical studies suggest that somatostatin, a regulatory peptide widely distributed in human tissues may have electrophysiologic effects. We studied a group of 14 patients who underwent a complete electrophysiologic study for different rhythm disturbances. Somatostatin significantly increased the spontaneous cycle length, the atrial and atrioventricular nodal effective refractory periods, and the Wenckebach cycle length. The AH and HV intervals during sinus rhythm remained unchanged. The effectiveness of somatostatin to interrupt paroxysmal supraventricular tachycardias was assessed in 18 patients. Termination was obtained in 15 (82.5%). Our results show that somatostatin has a significant electrophysiologic effect on the human heart, and confirm its clinical effectiveness in some arrhythmias.

Arrhythmias, Cardiac↗
PubMed1986

Somatostatin response to a mixed meal in normals and in type I diabetics.

Somatostatin has been proposed as a regulatory peptide of nutrient entry and fuel homeostasis because of its ability to inhibit the release of substances involved in food digestion and metabolism. The aim of the study was to evaluate the somatostatin response to a test meal in type I diabetics at the clinical onset of the disease and after two months of intensive insulin therapy. Normal subjects and diabetics in good metabolic control showed a characteristic biphasic somatostatin rise after a test meal; this response was lacking in diabetics at the onset of the disease. The response of somatostatin to a mixed meal in normals confirms its involvement in nutrient digestion and metabolism. The lacking somatostatin response in newly diagnosed type I diabetics might be related to deficient GIP response to the test meal or to other factors such as the insulinopenia or metabolic derangement characteristic of the clinical onset of the disease.

Adult↗
PubMed1986

The role of cAMP and prostaglandins in gastric acid secretion after pentagastrin administration.

The role of cAMP and prostaglandins as specific intracellular effectors of gastrin action at the level of the parietal cells has not been sufficiently clarified. For this reason we studied the responses of the parietal cells to stimulation with pentagastrin (6 micrograms/kg i.m.) during theophylline infusion (which causes an increase in the intracellular cAMP) and during acetylsalicylic acid infusion (which inhibits the prostaglandin synthesis) in 28 healthy volunteers. Both theophylline and acetylsalicylic acid provoked a significant increase of gastric acid secretion after pentagastrin. Our results suggest that: 1. an increase in intracellular cAMP may be the basis of the stimulatory effect of gastrin on gastric acid secretion 2. a decrease in the synthesis of prostaglandins may lead to a greater gastric acid response after pentagastrin.

Adolescent↗
PubMed1986

Evidence of extragastric gastrin release in postoperative ulcer patients.

The principal sites of gastrin production in man are localized at the level of the gastric antrum; both the oral glucose load and the protein meal stimulate the gastrin secretion. The aim of this study was to verify the gastrin response in patients with gastric resections presented with various stimuli. In the operated patients, the behavior of serum gastrin after a protein meal was different with respect to that observed in control subjects. After glucose, on the contrary, a very similar result was seen when compared to controls. The increase in serum gastrin of patients with Billroth II provides a further confirmation of an extragastric origin of gastrin.

Dietary Proteins↗
PubMed1986

The effect of lysine acetylsalicylate on somatostatin inhibition of insulin secretion induced by arginine.

The inhibitory effect of somatostatin (SRIF) on immunoreactive insulin release and on many other hormonal secretions has been widely studied in both animal and man. However, the mechanism by which SRIF acts on these functions remains poorly defined. Aim of this study is to determine the inhibitory effect of SRIF on insulin secretion induced by arginine after the administration of lysine acetylsalicylate (LAS) in a dose which inhibits the endogenous synthesis of prostaglandins. Ten healthy informed volunteer subjects were studied. Four studies were carried out in randomized order, each one separated by a three day interval. The first study was a test of arginine (25 g i.v. in 30 min). The second study was a test of arginine with SRIF infusion (150 micrograms bolus followed by 100 micrograms/h for 120 min). The third study was a test of arginine with an infusion of SRIF and LAS (66 mg/min for 120 min). The fourth study was a test of arginine with LAS infusion. Plasma insulin levels were determined by radioimmunoassay. After arginine administration the typical biphasic insulin response was observed with a precocious peak at 3 min and a late peak at 30 min. This response is not significantly modified under LAS infusion. With the infusion of SRIF at a dose of 100 micrograms/hr after arginine administration only a very modest insulin response was observed. The addition of LAS does not modify the inhibitory effect of SRIF on insulin secretion induced by arginine. This result demonstrates that the inhibitory action of SRIF on the secretion of insulin is not dependent upon the activation of the endocellular prostaglandin system.

Adult↗
PubMed1986

Stimulatory effect of pentagastrin on growth hormone and prolactin secretion in normal subjects.

Gastrin-like immunoreactive substances have been reported as occurring in both digestive tract tissues and nervous system, including the hypothalamus and the anterior and posterior pituitary. The carboxyterminal tetrapeptide shared by gastrin and cholecystokinin, which represents the bioactive site of both hormones, has been shown to be a secretagogue for insulin and glucagon and it might have a neurotrasmitter function. As small gastrin-like peptides may also play a role in the regulation of anterior pituitary hormones, the present study deals with the in vivo effect of pentagastrin on the release of growth hormone (GH) and prolactin (PRL). Six healthy volunteer males and six healthy volunteer females were studied. All females subjects were in the early follicular phase of the normal menstrual cycle and all subjects were not taking or had been taking any drug known to affect GH or PRL secretion. A continuous intravenous infusion of pentagastrin (1.5 micrograms/kg/h) was administered to all the subjects for a time of 3 hours. In males pentagastrin infusion resulted in a significant increase in GH concentration from basal values (P less than 0.01 at 60 min). In females pentagastrin infusion did not affect GH levels. PRL levels were not affected at all by intravenous pentagastrin infusion both in males and females. The exact understanding of pentagastrin action on GH release awaits further investigation. The different pattern between male and female subjects suggests a sexual hormone influence on the hypothalamic-pituitary sites of action of pentagastrin in vivo. Our data did not confirm a stimulatory effect of pentagastrin on PRL secretion in normal subjects.

Adult↗
PubMed1986

Somatostatin plasma levels and biological effects following subcutaneous administration of somatostatin in man.

The rate at which somatostatin appears in the circulation after subcutaneous bolus injection and continuous administration by pump was determined in normal subjects by serial radioimmunoassays of immunoreactive somatostatin. Following a single subcutaneous injection of 250 micrograms, the somatostatin peak in plasma appeared after 5 min and had only a transient effect on insulin levels. During continuous administration, somatostatin reached levels able to reduce significantly insulin and glucagon. Somatostatin plasma levels exerting biological effects were observed during the subcutaneous administration of the peptide.

Adult↗
PubMed1986

White cells transfusion in recent onset type 1 diabetes.

Two HLA-identical brothers developed Type 1 diabetes simultaneously. In the light of present knowledge of the pathogenesis of Type 1 diabetes, immunosuppression was adopted in one brother by means of white cell transfusion from the father. The other brother acted as a control. This immunosuppressive approach has been shown to be effective in kidney transplantation and, as far as Type 1 diabetes is concerned, in the BB Wistar rat. An immunological and metabolic follow-up study of 1 yr only revealed slight differences between the 2 brothers (who are both on insulin) but the pattern of lymphocyte activation appeared to become normalized earlier in the transfused brother.

Adolescent↗
PubMed1985

[Behavior of GH and prolactin during enflurane anesthesia and neuroleptoanesthesia in man].

The present study was designed to investigate the effects of neuraleptanesthesia (NLA) and enflurane (Ethane) anesthesia on plasma levels of growth hormone (GH) and prolactin (PRL) in man. A total of 18 patients aged between 20 and 65 years scheduled for elective open-heart surgery were divided in two groups. In the first group (9 patients) general anaesthesia was induced with sodium thiopental (TPS) (3-5 mg/kg) and was maintained with enflurane administered with an inspired concentration of 1.5% in nitrous oxide (2 litres/min) and oxygen (2 litres/min). In the second group (9 patients) anaesthesia was induced with dihydrobenzopyridol (BPS) (0.1-0.2 mg/kg), fentanyl (5-8 gamma/kg) and TPS (3-5 mg/kg) and was maintained with fentanyl (0,65 mg in average). The patients had neither hepatic, renal or endocrine disease nor did they have a history of steroid therapy. All subjects received atropine (0.01 mg/kg) and diazepam (0.2 mg/kg) i.m. 2 hours before induction of anaesthesia. Blood samples for GH and PRL was collected before induction of anaesthesia (0) and at 30, 60, 90 and 120 minutes after induction: the 90' sample was taken immediately after sternal incision. The sampling was stopped at the start of the cardiopulmonary by-pass. A significative reduction of GH at 60' and of PRL at 30' was observed in both groups. Surgical stress at 90' does not evoke a significant increase of PRL and GH levels in both groups. In conclusion NLA and enflurane induced a decrease of GH and PRL plasma levels; in both groups the anaesthetic agents, at the dosage used during anaesthesia, blocked the response of these hormones to the surgical stress likely due to a block of the hypothalamic-pituitary response.

Adult↗
PubMed1985

[Blood catecholamines in liver cirrhosis].

Haematic concentrations of catecholamines were found to be higher in cirrhotic patients with ascites, than cirrhotic patients without ascites and controls. In compensated and decompensated cirrhosis, different forms of sympathetic nervous activity were observed. The high catecholamine values in cirrhotic patients and the activation of the renin angiotensin-aldosterone system suggest the use of beta-blockers to reduce sodium-water retention.

Adrenergic beta-Antagonists↗
PubMed1985

[Gastroenterologic aspects of connective tissue diseases].

The connective tissue disorders are a protean group of acquired diseases which have in common widespread immunologic and inflammatory alterations of connective tissue. The acquired connective tissue diseases generally include the following clinical entities: rheumatoid arthritis, systemic lupus erythematosus, polymyositis, polyarteritis nodosa, scleroderma, mixed connective tissue disease, Sjögren's and Behcet's sindromes. These entities have certain features in common which include sinovitis, pleuritis, myocarditis, endocarditis, pericarditis, peritonitis, vasculitis, myositis, changes in skin, alteration of connective tissue and nephritis. Gastrointestinal and hepatic involvement in connective tissue disorders are not the most important features, nevertheless appear almost regularly. Anorexia, nausea, vomiting, abdominal pain, malabsorption may affect patients suffering by rheumatoid arthritis, systemic lupus erythematosus and other collagenophaties. In some cases mesenteric vasculitis may cause intestinal ischemia which may result in bowel infarction, mucosal ulceration, hemorrhage, perforation. After an extensive review of the existing literature the Authors make an accurate evaluation of gastrointestinal and hepatic alterations in connective tissue diseases.

Arthritis, Rheumatoid↗
PubMed1985

Relapsing polychondritis with severe aortic insufficiency.

Relapsing polychondritis (RP) is a rare disease characterized by auricular, nasal and respiratory tract chondritis, ocular inflammation, inflammatory polyarthritis and cardiovascular abnormalities. Here we describe a patient with a five-year history of mild nasal and auricular chondritis, which suddenly developed into a severe aortic insufficiency with rest dyspnea. The pathogenesis and the management of this rare connective tissue disease are discussed.

Adult↗
PubMed1985

Chronic active hepatitis and Behçet's syndrome.

In a patient with Behcet's syndrome the finding of five times the normal level of serum transaminase accompanied by weakness may be correlated to the syndrome itself. We performed needle biopsy of the liver in our patient which showed piecemeal necrosis and portal lympho-monocytic infiltration extending into the lobule. It is interesting that HLA B5 and B27 antigens were present. Simultaneous occurrence of chronic active hepatitis and Behcet's syndrome may imply the same autoimmune pathogenesis, as we suggest in this work.

Alanine Transaminase↗
PubMed1985

[Somatostatin and the cardiovascular system: experiences and prospective use].

The recent demonstration that intravenous administration of somatostatin, an ubiquitous peptide-like substance, may interrupt paroxysmal supraventricular tachycardia in man has disclosed new perspectives in the assessment of the mechanisms of neuro-humoral cardiac regulation in normal and pathologic conditions. Prospective studies on normal subjects and diabetics with and without autonomic cardiac neuropathy, helped in giving an outlook on the mechanism by which somatostatin acts on the human heart. This substance exerts in vivo a powerful chronotropic and dromotropic influence on sinoatrial and A-V node cells both in normals and diabetics with and without autonomic cardiac neuropathy. This influence is blocked by preventive administration of atropine or atropine plus metoprolol (intrinsic heart rate). Since somatostatin-like-substances have been found in cholinergic postganglionic neurons of the cardiac vagus of some animals, the demonstrated "vagomimetic" action of somatostatin on human cardiac cells seems to support the hypothesis that also the human heart may contain vagal somatostatinergic neurons with modulatory function on the heart rate and rhythm. Present observations disclose new perspectives in the pathophysiology and therapy of cardiac arrhythmias.

Adult↗
PubMed1984

[Serum bile acids in dyslipidemic patients].

The sensitivity of total serum bile acid concentration as an index of hepatic damage has long been recognised. In addition serum bile acid measurement is significantly more specific than conventional hepatic function tests. However the concentration might be affected by factors other than hepatic dysfunction. Several authors have reported variations in the synthesis of serum bile acids in dyslipidaemic patients. This might potentially reduce the value of concentration measurement in the diagnosis of hepatic diseases especially considering the relative prevalence of hyperlipidaemia. The present article reports on radioimmunological serum bile acid measurement before and after meals in 10 patients with dyslipidaemia and in 22 controls. No difference was revealed between the two groups. Therefore dyslipidaemia appears not to affect the specificity of the test nor does it invalidate the use of radioimmunological measurement of total serum bile acids in the study of hepatic function.

Aged↗