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P Forte

Publications and source records attributed to P Forte.

32 records · Page 2Linked to original sources
PubMed1995

Membrane expression of HLA-Cw4 free chains in activated T cells of transgenic mice.

Transgenic mice were produced in which human HLA-Cw4 is stably integrated, behaves as a single Mendelian trait, and, being under the transcriptional control of human CD2, is selectively and efficiently expressed in T lymphocytes. These mice were used as a model system to determine whether HLA-type C molecules can be exposed on the surface of activated lymphocytes as free heavy chains, non-associated with beta2-microglobulin (beta2m). In our transgenic mice we could identify HLA-Cw4 molecules either as free chains or as beta2m-associated molecules by the use of monoclonal antibodies specific for either conformation of HLA class I and nonreactive to mouse H2 molecules. Resting mouse lymphocytes were shown by western transfer analysis to contain sizeable amounts of HLA-Cw4 free chains, but they exposed on their surface HLA-Cw4 only in association with beta2m, as indicated by flow cytometric measurements. Conversely, where the content of total HLA-Cw4 was increased, lectin-activated mouse lymphocytes exposed on their outer cell membrane HLA-Cw4 molecules in both conformations, namely, also as free heavy chains. Isoelectrofocusing analysis confirmed the presence of both HLA-Cw4 molecular conformations in activated T cells and indicated that HLA-Cw4 heavy chains can bind to mouse beta2m with the same low affinity displayed for human beta2m. The results of our experiments led us to conclude that (1) association with beta2m is not necessary for the exposure of HLA-C on the surface of activated T lymphocytes and (2) cell activation affects the balance between the two conformational forms of HLA-C.

Animals↗
PubMed1995

Metoclopramide blocks bromocriptine induced antihypertensive effect in hypertensive patients.

Two groups of patients with essential hypertension were studied at the Vargas Hospital of Caracas. The first group of 9 patients under placebo treatment for 1 week received a single 2.5 mg oral dose of bromocriptine. Cardiovascular and biochemical parameters including arterial pressure, heart rate, plasma renin activity, and plasma aldosterone levels were evaluated during the 6-hour period before and after the administration of drugs. The second experimental design was as follows: 9 patients received 30 mg metoclopramide daily (divided in 3 doses) for 1 week. At the end of the period a single oral dose of 2.5 mg of bromocriptine was given to each patient. The cardiovascular and biochemical parameters were also determined. Bromocriptine reduced both systolic and diastolic arterial pressure. The peak antihypertensive effect was shown 3 hours after administration of the drug, but the reduction of arterial pressure lasted approximately 6 hours. At the same time bromocriptine reduced plasma aldosterone levels and plasma renin activity. This reduction persisted 6 hours after its administration. Metoclopramide reversed the antihypertensive effect of bromocriptine and its effect on aldosterone secretion and plasma renin activity. We conclude from these findings that bromocriptine acts as an antihypertensive agent by stimulating DA2 dopaminergic receptor, the dopaminergic receptor involved in aldosterone and renin secretion is possibly DA2.

Aldosterone↗
PubMed1994

Dopamine-induced antihypertensive effects and plasma insulin rise are blocked by metoclopramide in labetalol-treated patients.

Eleven patients with moderate to severe hypertension were studied at the Vargas Hospital of Caracas. The patients were pretreated with labetalol, 800 to 1200 mg/day, orally, over a period of 1 week, after which an intravenous infusion of dopamine, .5 to 3 micrograms/kg/minute, was given. Two intravenous dopamine infusions (30 minutes each) were performed before and after the injection of metoclopramide (30 mg, intravenous bolus). Two washout periods were also included before and after metoclopramide administration. Dopamine induced a decrease of blood pressure from 171.9 + 6.35/103.6 +/- 3.12 to 152.7 +/- 7.55/93.8 +/- 2.97 mm Hg (P < .001) without altering heart rate, and it increased plasma insulin levels from 8.29 +/- .70 microU/mL to 12.09 +/- 1.83 microU/mL (P < .01). Metoclopramide caused no changes of blood pressure or plasma insulin levels. Hypotensive responses and plasma insulin increases due to dopamine were blocked by metoclopramide, however. The authors conclude that a dopaminergic receptor may be involved in some cardiovascular responses and in modulating insulin secretion in humans.

Blood Glucose↗
PubMed1993

Effect of intravenous dopamine on blood pressure and plasma insulin in hypertensive patients.

Eleven patients with moderate to severe hypertension were pre-treated with oral labetalol 800-1200 mg/day for one week, prior to receiving two i.v. infusions of dopamine 1-3 micrograms/kg/min each of 30 min each, before and after the i.v. bolus injection of metoclopramide 30 mg. There were washout periods before and after the metoclopramide administration. Dopamine induced a significant decrease of blood pressure from 172/104 to 153/94 mm Hg without altering heart rate, and it increased the plasma insulin level from 8.3 to 12.1 microU.ml-1. Metoclopramide did not itself affect blood pressure or plasma insulin, but it did block the hypotensive response and rise in plasma insulin due to dopamine. We conclude that the pharmacological actions of intravenous dopamine on the cardiovascular system and on insulin secretion may be mediated by dopaminergic receptor stimulation.

Blood Glucose↗
PubMed1993

Effects of dopaminergic antagonists on dopamine-induced cardiovascular and insulin secretion actions in hypertensive patients.

A comparative study between two dopaminergic antagonists: metoclopramide and domperidone, was undertaken in nineteen (19) hypertensive patients at the Vargas Hospital, Caracas. The patients were pretreated with labetalol, 800-1,200 mg/day, orally, over a period of one week, after which they were divided into two groups: group A, a total of eleven patients were intravenously infused with dopamine hydrochloride 0.5-3 micrograms/kg/min, before and after treatment with metoclopramide (10 mg, i.v. as a bolus); group B (n = 8), was pretreated with domperidone, 20 mg b.i.d., p.o. over a period of one week and intravenously infused with dopamine hydrochloride, 0.5-3 micrograms/kg/min. In group A, dopamine induced a decrease of blood pressure from 171.9 +/- 6.35/103.6 +/- 3.12 to 152.7 +/- 7.55/93.8 +/- 2.97 mmHg (p < 0.001) without altering heart rate, and it increased plasma insulin levels from 8.29 +/- 0.70 microunits/ml to 12.09 +/- 1.83 microunits/ml (p < 0.01). Metoclopramide caused no changes of blood pressure or plasma insulin levels. However, hypotensive responses and plasma insulin rises due to dopamine were blocked by metoclopramide. In group B, domperidone also blocked dopamine-induced antihypertensive effect (from 170.0 +/- 9.23/102.8 +/- 3.80 to 160.2 +/- 9.84/95.5 +/- 2.50 mmHg) although it was less effective than metoclopramide. Domperidone also blocked dopamine-induced increase of plasma insulin levels from 9.65 +/- 4.50 microunits/ml to 11.78 microunits/ml. We conclude that a dopaminergic receptor may be involved in some cardiovascular responses and in modulating insulin secretion in man.

Blood Glucose↗
PubMed1992

Tetanus immunity in a partially vaccinated population of children in a district of Naples (Secondigliano).

A general opinion is that compliance with the compulsory immunization programme of children is excellent in Italy. We have studied antitetanus immunity in relation to vaccination history in a sample of 444 school children born between 1977 and 1981 in a district of Naples. Information on vaccination history was collected by interviewing the parents and validated using the official vaccination certificates. Titration of antibodies against tetanus was carried out by the immunoenzymatic method. 0.9% of our study subjects had not been vaccinated at all and only 21.2% had received 4 vaccine doses. In 18 children the presence of antitetanus antibodies was not detected; 14 of them had received one or more doses of vaccine. The lack of compliance with the vaccination programme was associated with a remarkable delay in administering the tetanus vaccine. In the population reported here, the percentage of subjects only partially covered is higher than that found in other regions of Italy.

Child↗
PubMed1989

Cooperativity in nucleosomes assembly on supercoiled pBR322 DNA.

Many studies have shown that in reconstituted chromatin model systems, containing only purified DNA and histone octamer, nucleosomes can adopt well defined locations with respect to DNA nucleotide sequence. Recently, nucleosome-nucleosome interactions were suggested as one of the factors underlying preferential nucleosomes positioning. In the present paper this aspect has been studied by topological analysis and electron microscopy visualization of minichromosomes reconstituted at different histone/DNA ratios. Both methods suggest that cooperativity plays a role in nucleosomes formation. A linear cooperative model in which nucleosomes are formed on discrete sites with cooperative interactions occurring only between nearest neighbours allows to calculate the cooperative constant. The reported results show that basic interactions, which are of relevance in the process of chromatin folding, are present also in very simple model system.

Animals↗
PubMed1989

Decline in the exposure to hepatitis A and B infections in children in Naples, Italy.

In May 1988, the hepatitis A antibody (anti-HAV) and hepatitis B virus (HBV) markers were studied by radioimmunoassay in 484 apparently healthy children between the ages of 7 and 12, attending a primary school in Naples, Italy. The overall anti-HAV prevalence was 11.2%, increasing from 5.2 in 7-year-old children to 28.2% in children between the ages of 11 and 12 years old. The overall prevalence of the hepatitis B surface antigen (HBsAg) and of other HBV markers were 0.8 and 6.8 respectively. Compared with a similar previous study conducted in Naples in 1980, the results show a significant reduction in the prevalence of anti-HAV in each of the two age-groups (P less than 0.01), in the prevalence of any HBV marker in the 11 to 12-year-old group, as well as in the total population (P less than 0.05). The findings of the present study indicate that today, children in Naples are less exposed to the hepatitis A virus than in the past, most likely because of improvements in both the socioeconomic conditions and in health education during recent years. These same reasons, as well as decreased family size and a lower prevalence of HBeAg among HBsAg carriers could explain the decline, although to a lesser degree, of exposure to HBV infection.

Child↗
PubMedDate not supplied

Adhesive interactions between human NK cells and porcine endothelial cells.

Human natural killer (NK) cells are able to adhere to xenogeneic porcine endothelial cells (EC) and evidence from in vitro studies as well as animal models suggests a potential role for NK cells in the cellular recognition and damage of porcine xenogeneic tissues. One possible explanation for the observed NK cell-mediated xenogeneic cytotoxicity against porcine EC is the molecular incompatibility between porcine major histocompatibility complex (MHC) class I molecules and MHC-specific inhibitory receptors on human NK cells. In this review we attempt to summarize the current knowledge concerning adhesive interactions between human NK cells and porcine EC under special considerations of the cross-species receptor-ligand interactions. Methodological differences in assessing adhesion between various studies are reviewed and comparisons to the syngeneic/allogeneic adhesion mechanisms are made. Finally, the therapeutic potential of blocking antibodies and transgenic HLA expression in preventing NK-cell adhesion and xenogeneic cytotoxicity is discussed.

Animals↗
PubMedDate not supplied

Approach to respiratory failure in emergency department.

OBJECTIVES AND BACKGROUND: The goal of this review is to provide update recommendations that can be used by emergency physicians who provide primary cares to patients with Acute Respiratory Failure (ARF), from the admission to an emergency department through the first 24 to 48 hours of hospitalization. This work wants to address the diagnosis and emergency medical care of ARF and the management of medical complications. STATE OF THE ART: A lot of statement has been developed for the early management and treatment of ARF; moreover, over the last fifteen years, we have assisted to the rise of a new technique of ventilation, in the Emergency Department: Non Invasive Ventilation. This kind of ventilation was firsthy applied in intensive Care and in Respiratory Care Unit. Randomized controlled clinical trials have showed its usefulness in the early treatment of several forms of ARF, together with medical therapy.

Acute Disease↗
PubMedDate not supplied

[Association of pulmonary and portal hypertension].

The association between portal venous hypertension and pulmonary arterial hypertension has received scarce attention in the italian medical literature. Nevertheless the association is relatively frequent, it needs a multidisciplinary approach and it is a stimulus for the search of causes of so-called primary pulmonary hypertension. The purpose of the article is to review the frequency of the association, the main pathogenetic hypothesis formulated to explain the appearance of pulmonary hypertension, the clinical and the laboratory findings, the evolution of the association and to present briefly a personal series of cases. The pulmonary arterial hypertension has been found in approximately 2% of patients with portal hypertension due to either hepatic cirrhosis or extraepatic lesions. Microembolism from the portocavat system or a number of vasoactive substances which enter the pulmonary circulation without being inactivated by the liver have been held responsible for the appearance of pulmonary hypertension in predisposed patients. Clinical and laboratory findings do not differ from those a patients with primary pulmonary hypertension. Also the prognosis is similar. In conclusion on accurate examination of the pulmonary circulation by noninvasive methods, in particular by echocardiography, appears to be mandatory in patients with chronic hepatic lesions. When pulmonary arterial hypertension is detected the study of the biochemical factors which at present are known to determine pulmonary hypertension may be warranted. The study may enhance our knowledge of the pathogenesis of the so-called primary pulmonary hypertension.

Adult↗