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Biomedical subjects

G Squadrito

Publications and source records attributed to G Squadrito.

At least 91 records · Page 5Linked to original sources
PubMed1991

[Changes in the QT interval caused by autonomic cardiovascular involvement in diabetes mellitus].

The aim of the study was to assess the role of altered autonomic regulation on changes in the QT interval. Fifty-three diabetic patients, comprising 32 men and 21 women with a mean age of 49.4 +/- 15.9 years (range 13-73 years), underwent sympathetic and parasympathetic stimulatory tests (changes in heart rate between clino- and orthostatism, lying to standing, while deep breathing, Valsalva's manoeuvre, changes of arterial pressure related to posture) to study cardiovascular reflexes. Patients who were positive for at least two of the tests were considered to be affected by autonomic neuropathy. Ten non-diabetic age-matched subjects (44.8 +/- 14.8 years) with no cardiovascular diseases were included in the study as a control group. The QTc interval was measured in basal conditions and during sympathetic and parasympathetic stimulatory tests, in clino- and orthostatism, during deep breathing and Valsalva's manoeuvre. A significantly greater QTc interval (p less than 0.05) was found in neuropathic patients compared to controls and non-neuropathic patients both in basal conditions and following stimulatory tests at the lowest heart rate (phase IV of Valsalva's manoeuvre and slow exhalation during deep breathing), while at a higher heart rate (orthostatism, L-S, deep inhalation during deep breathing, phase II of Valsalva's manoeuvre) there was no difference in QTc between controls, and neuropathic and non-neuropathic patients due to a lesser extension of the QTc in neuropathic patients. This difference appears to be the expression of autonomic dysregulation in neuropathic patients, given the lack of correlation with diabetes or duration of disease, and is only conditioned by the presence or absence of autonomopathic damage. Among other causes, the observed extension of the QT interval might therefore justify the increased frequency of sudden death in diabetic patients with cardiovascular autonomic neuropathy.

Adolescent↗
PubMed1990

Hepatitis B virus (HBV) markers and HBV-DNA in serum and liver tissue of patients with acute exacerbation of chronic type B hepatitis.

We analysed the serum samples and the liver biopsies of six consecutive chronic HBsAg/anti-HBe carriers admitted to hospital because of an episode of acute hepatitis. The six patients became positive for IgM anti-HBc and negative for HBeAg, hepatitis Delta virus (HDV) markers, IgM anti-hepatitis A virus (HAV), anti-cytomegalovirus (CMV) and anti-Epstein-Barr virus (EBV). Two patients showed positivity for hepatitis B virus (HBV)-DNA in serum obtained on admission, with no positivity in the subsequent weeks; the results of the other four patients were always negative for seric HBV-DNA. The Southern-blot analysis of the DNA extracted from the liver tissue of four subjects showed the presence of HBV-DNA in the form of replicative intermediates; focal positivity of HBcAg was detected in the liver of only one. The liver biopsies of the last two patients were negative for HBV-DNA and for HBcAg. The analysis of HBV-DNA in the liver extracts and the demonstration of an increase of the IgM anti-HBc titre at the time of the abrupt elevation of the aminotransferase levels seem to be the most useful tools in revealing HBV activation as a cause of acute hepatitis in chronic HBsAg carriers, overall when the phase of viremia is transient.

Antigens, Viral↗
PubMed1990

Latency and reactivation of a precore mutant hepatitis B virus in a chronically infected patient.

In human patients infected with hepatitis B virus (HBV) seroconversion from HBe to anti-HBe often signals virus elimination. Occasionally, a second viremic phase is observed which may be due to superinfection with a variant or reactivation of a latent virus. To differentiate between these two possibilities we investigated the nucleotide sequences of virus populations from sera of a chronically infected patient who had two distinct viremic phases, one e-antigen positive and one anti-HBe antibody positive. By direct sequencing of amplified HBV C- and pre-S gene sequences we found that the viruses in the two populations differed by only two point mutations, one of which prevents expression of precore derived e-antigen. In the nonviremic phase viral DNA and antigen were found in the liver but nucleocapsid protein expression appeared drastically downregulated. These data demonstrate that HBV can enter a latent phase with low expression of core protein and selection for HBV variants which cannot synthesize e-antigen. This suggests that e-antigen expression can be a critical target for virus elimination and that loss of its expression can prolong chronicity and provoke latency of HBV infection.

Antigens, Viral↗
PubMed1990

Effects of intracerebroventricular administration of magnesium sulphate on blood pressure and heart rate in anesthetized normotensive and hypertensive rats.

Intracerebroventricular (i.c.v.) injection of magnesium sulphate (MgSO4:2.5, 5 and 10 mumol in 5 microliters) decreased blood pressure and heart rate in both anesthetized normotensive (WKY) and hypertensive rats (SHR). The effects were greater in WKY than in SHR. Moreover, a pretreatment with hexamethonium (2 mg/kg, i.v.) significantly blunted the hypotensive and bradycardic effects induced by i.c.v. injection of 10 mumol of MgSO4 in both WKY and SHR. Our data suggest that MgSO4 produces hypotensive and bradycardic effects when injected i.c.v. in both WKY and SHR.

Anesthesia↗
PubMed1989

Hepatitis B-DNA replication and histological patterns in liver biopsy specimens of chronic HBsAg positive patients with and without hepatitis delta virus superinfection.

The role of active hepatitis B virus (HBV) infection in chronic HBsAg positive hepatitis with and without hepatitis delta virus (HDV) superinfection was analysed in percutaneous liver biopsy specimens from 50 patients. Each specimen was divided into two--one part for histological evaluation and for the detection of HBcAg and delta antigen; the other part was tested for HBV-DNA using Southern blotting. Ten cases were of chronic lobular hepatitis, 10 of chronic persistent hepatitis, and 30 of chronic active hepatitis. Ten cases were delta antigen positive and showed high grade lobular activity but no evidence of HBV-DNA episomal forms or HBcAg reactivity. Twenty one cases showed HBV-DNA replicative intermediate forms; 19 had high grade lobular activity, which occurred in five cases without evidence of free viral DNA. Of the 21 biopsy specimens with HBV-DNA episomal forms, 14 were positive for HBcAg; only one of the 19 cases without detectable viral DNA was positive for such antigen. These data indicate that the presence of HBV or HDV active infection correlates with the histological finding of prominent lobular necrosis. Moreover, intrahepatic HBV-DNA seems to be a more sensitive marker than the presence of viral antigens for indicating HBV replication.

Carrier State↗
PubMed1989

A comparison of synthetic human and rat ANP administered intracerebroventricularly in freely moving normotensive and hypertensive rats.

The effects of intracerebroventricular (i.c.v.) injection of alpha-human atrial natriuretic peptide (alpha-hANP) and alpha-rat atrial natriuretic peptide (alpha-rANP) were studied in normotensive [Wistar-Kyoto (WKY)] and spontaneously hypertensive rats (SHR). Intracerebroventricular injection of alpha-hANP (200, 400, and 800 ng in 5 microliters) did not modify mean arterial pressure (MAP), heart rate (HR), and water intake in both WKY rats and SHR. On the contrary, alpha-rANP (200, 400, and 800 ng in 5 microliters) caused strong dipsogenic, pressor, and bradycardic effects that were greater in hypertensive than in normotensive rats. Saralasin (9 microns in 5 microliters), injected 2 min prior to alpha-rANP, abated these effects, thus indicating an involvement of brain angiotensin. Our results suggest that, at least as far as the cerebral effects of ANP are concerned, some difference exists between alpha-rANP and human atrial natriuretic peptide.

Animals↗
PubMed1987

Central dipsogenic effect of synthetic rat atrial natriuretic polypeptide in normotensive rats.

The effect of intracerebroventricular (i.c.v.) injection of synthetic rat atrial natriuretic polypeptide (alpha-rANP) on drinking behavior was studied in normotensive rats, alpha-rANP (0.2, 0.4 or 0.8 micrograms in 5 microliter) caused a dose-dependent dipsogenic effect which was abated by i.c.v. pretreatment with saralasine (9 micrograms in 5 microliter). These results suggest that alpha-rANP possesses dipsogenic effects in water repleted rats and that brain angiotensin is involved. In addition, our data indicate that, at least as far as the effect of cerebral ANP is concerned, there are some differences between alpha-rANP and human atrial natriuretic polypeptide.

Animals↗
PubMed1985

Role of brain cholinergic system in the antihypertensive effect of clonidine in different models of rat hypertension.

Acetylcholine in the central nervous system appears to be involved in some aspects of hypertension. Clonidine and methyldopa may inhibit acetylcholine (Ach) release in several brain areas. The present study was therefore designed to determine whether a depletion of brain Ach could modify the antihypertensive effect of clonidine in freely moving spontaneously hypertensive (SHR), Grollman hypertensive (GHR) and DOCA-salt hypertensive (DHR) rats. Intravenous injection of clonidine (15, 30 and 75 micrograms/kg) reduced mean arterial pressure (MAP) and heart rate (HR) in all hypertensive animals. The hypotensive effect was more marked in SHR than in DHR and GHR. The effect was also reproducible when the drug dose was repeated 3 h later in rats pretreated with saline (5 microliters) in the lateral cerebral ventricle (i.c.v.). When clonidine administration was repeated in hypertensive animals 3 h after i.c.v. hemicholinium-3 (20 micrograms/5 microliters), the decrease in MAP and HR was significantly reduced compared with that observed in the same animals after the first injection. The data suggest that the antihypertensive effect of clonidine depends partially upon the integrity of central cholinergic neurons.

Acetylcholine↗
PubMed1984

Delta agent infection in acute hepatitis and chronic HBsAg carriers with and without liver disease.

Hepatitis B virus (HBV) is a major cause of chronic liver disease in southern Italy. In the same area superinfection with the delta agent is endemic. To assess the prevalence of delta infection in a large population of patients with acute and chronic HBV related liver disease and to look for differential features among delta infected and uninfected subjects sera from 592 consecutive HBsAg positive patients were tested for the delta/anti-delta system by RIA. In no case was delta Ag found in serum. The prevalence of anti-delta was low in acute hepatitis (6.6%) and in asymptomatic carriers (6.4%) but raised in chronic active hepatitis with or without cirrhosis (52.3%). A decrease in frequency of anti-delta was seen in inactive cirrhosis (38.8%) and in hepatocellular carcinoma (11.9%). A younger mean age of delta-infected subjects was observed in each type of chronic liver disease. Our data confirm that delta agent superinfection is definitely associated with severe chronic active liver disease. The difference in age between anti-delta positive and negative patients suggests that delta infection accelerates the natural history of HBV related liver disease.

Acute Disease↗
PubMed1981

[The vasoactive effects of captopril (SQ 14225). Preliminary research].

The Authors examined the behaviour of the humeral arterial pressure, of the heart frequency and of the muscular blood flow in inferior limbs. This study was performed before and after treatment with Captopril (SQ 14225), 100 mg per os, a selective inhibitor of the converting enzyme. Both resting blood flow (RBF) and maximal blood flow (NBF) were studied by Xenon 133 clearance. The A.A. observed that the drug induced a significant (P less than 0.01) increase of both RBF and MBF. Therefore, the Authors hypothesize that the Captopril is able to produce peripheral vasodilatation, without any significant variation of the cardiac index and frequency. Such an effect is considered to depend not only upon the inhibited angiotensin II production, but also upon stimulation of bradikinins and prostaglandins.

Adult↗