Search PubMed⌕ Search

Biomedical subjects

M Piazza

Publications and source records attributed to M Piazza.

At least 37 records · Page 2Linked to original sources
PubMed1989

Mycelium-yeast transition in Histoplasma capsulatum. Early ultrastructural changes.

The ultrastructural changes which occur during the first 24 h of mycelium to yeast transition have been studied in the dimorphic fungus Histoplasma capsulatum. A temperature shift controls mycelial to yeast transition. During the first 24 h respiratory rate, ATP and cytochrome concentration fall to very low levels. Ultrastructural observations showed that the plasma membrane became undulated and the cell wall lost its characteristic fibrous outer layer. At 8 h the ordered lamellar structure of the mitochondria was no longer apparent. 24 h after the temperature shift 70% of the cells were lysed. The remaining cells contained many cytoplasmic membrane structures; mitochondria were rarely observed. These changes are considered to be the morphological expression of the physiological events characteristic of stage one in mycelial to yeast transition.

Histoplasma↗
PubMed1989

Immunogenicity of a DNA-recombinant hepatitis B vaccine (Engerix B) given at 3, 5 and 11 months of age with a new schedule suitable for mass vaccination programmes.

Following the demonstration of a fully satisfactory immunogenic activity of a hepatitis B vaccination protocol consisting of three doses given at the 3rd and 5th months of age with a booster at 11, it was possible to administer this vaccine at the same times as the vaccinations for diphtheria, tetanus and polio which are mandatory in Italy at those ages. A field trial of this protocol in a hyperendemic area near Naples (prevalence of HBsAg about 14%) started on January 1987. The French vaccine, Hevac B, Pasteur, was used. At this time compliance is 99%, and fully satisfactory results both in terms of seroconversion rate (96.3%) and of mean anti-HBs titre (4,352 mIU/ml) two months after the booster dose have been obtained. In this paper we demonstrate that even for a new hepatitis B vaccine prepared by a DNA-recombinant technique (Engerix B, SK & F) recently introduced in Italy, the same schedule can be used. In fact two doses of this vaccine, the first given at three months of age and the second two months later, resulted in a 100% seroconversion rate and a mean anti-HBs titre of 560 mIU/ml. Two months after the booster given at 11 months of age the mean anti-HBs titre was 12,100.

Drug Evaluation↗
PubMed1989

Prevalence of intranuclear particles in liver pathologies.

An ultrastructural study of the prevalence of electron dense 23-27 nm intranuclear particles was carried out on liver biopsies from patients with NANB chronic active hepatitis (CAH), Delta + CAH, HBsAg + CAH, nonviral liver pathologies and in one healthy volunteer. The particles were classified according to aggregation pattern and were found to be correlated with NANB CAH and Delta + CAH. No particles were observed in nonviral liver pathologies. A close antigenic relationship has been shown between the cytoplasmic alterations observed in NANB and delta hepatitis in chimpanzees. Our data indicate that there is a structural similarity between the intranuclear particles seen in both Delta and NANB hepatitis, thus reinforcing the hypothesis that the NANB and Delta agents are closely related.

Adult↗
PubMed1985

Hepatitis B immunisation with a reduced number of doses in newborn babies and children.

74 healthy babies born to mothers positive for hepatitis B surface antigen (HBsAg) were randomly divided at birth to receive either HB immunoglobulin and 2 doses of HB vaccine 2 months apart, or HB immunoglobulin and 3 doses of HB vaccine 1 month apart. 80 healthy babies born to HBsAg, anti-HBs, and anti-HB core (c) negative mothers were randomly divided at birth to receive either 2 doses of vaccine 2 months apart or 3 doses 1 month apart. The seroconversion rates and the geometric means of anti-HBs titres were lower in both groups of babies given 2 doses of vaccine than in the groups given 3 doses. 60 pairs of children at risk, aged 1 to 12 years and HBsAg, anti-HBs, and anti-HBc negative, were randomly divided to receive either the 2-dose regimen or the 3-dose regimen. The seroconversion rates and the geometric means of anti-HBs titres were satisfactory in both groups.

Child↗
PubMed1984

[Unusual ultrastructural findings in a case of asymptomatic primary biliary cirrhosis].

The investigators report an ultrastructural study of a case of primary biliary cirrhosis histologically in stage II (Scheuer), a rare disease which has not been investigated extensively at the ultrastructural level. Biliary canaliculi are dilated and microvilli are scarce. Large granular formations are observed in the perisinusoidal cytoplasm. The plasma membrane between adjacent hepatocytes appears convoluted. The ultrastructural alterations of the biliary canaliculi which we observed have been described in the literature in cholestatic patients and ascribed to cholestasis. Our patients, however, has never suffered episodes of jaundice or itching and has no histological signs indicating cholestasis. We suggest that these are precocious alterations which precede the appearance of clinical and histological signs of cholestasis. It is necessary to study other cases in order to evaluate the significance of the large granular formations and the changes observed in the plasma membrane.

Adult↗
PubMed1983

Pathological anatomy of the heart in noncardiogenic shock.

The main study methods used in situations of cardiogenic shock were applied to the hearts of patients who died of noncardiogenic shock, namely, the macroscopic nitro-BT test and histological examination for waves, contraction bands and coagulation necrosis. The hearts studied were obtained at autopsy from 20 patients who had died of hemorrhage due to the rupture of esophageal varices, from 18 patients who had died of massive pulmonary embolism and 15 patients who had died of noncardiogenic shock of different origin as well as 20 Wistar albino rats subjected to hemorrhagic shock. It was seen that all the forms of shock that were examined led to severe ischemic myocardial damage, as demonstrated by a positive nitro-BT test.

Adult↗