Biomedical subjects

S Leoni

Publications and source records attributed to S Leoni.

111 records · Page 7Linked to original sources

PubMedDate not supplied

Functional changes of endoplasmic reticulum membranes associated with liver regeneration.

The fluidity and lipid composition of microsomal membranes have been studied at the earliest stage of liver regeneration in the rat (16 h after partial hepatectomy). The physical properties of the membranes have been measured by electron paramagnetic resonance analysis of freedom of motion of lipid and protein analogue probes. The fluidity of the hydrophobic core and of the microenvironment surrounding membrane proteins appeared to be modified, while no modifications were detectable in the fluidity at the surface or in bulk biochemical composition. The kinetic parameters of two enzymes of the endoplasmic reticulum (3-hydroxy-3-methyl glutaryl coenzyme A reductase and glucose-6-phosphatase) which are differentially localized within the membrane bilayer, were also measured. The temperature dependence of both enzymes was modified in the proliferating system, but these modifications were not consistent with the changes detectable in their specific activity. A model to explain the changes that occur in this proliferating membrane system is presented.

Animals↗

PubMedDate not supplied

Electrophoretic analysis of normal and regenerating rat liver membrane proteins.

It is known that the cell surface of transformed cells shows a composition different from that of normal cells. Since the growth response is one of the parameters which appears to be altered, i.e. transformed cells continue to proliferate under such conditions in which normal cells do not, each alteration of the membrane connected with transformation could be involved in proliferation control mechanisms. Therefore such modifications could be expected to occur also in normal cells undergoing mitotic stimulations. Our work aimed to test whether this hypothesis is true also in the case of regenerating liver following partial hepatectomy. Electrophoresis was performed with polyacrylamide gel additioned with SDS in liver membranes from rats partially hepatectomized from 4h, 15h and 24h and solubilized with different detergents (solutions A, B and C). From the results we observed that liver membranes from 4h hepatectomized rats show a decrease in the amount of high molecular weight proteins; the appearance of two additional bands with molecular weight about 40,000 was also detected. At 15h after operation we observed a percent increase in the high molecular weight areas and a decrease in the low molecular weight one.

Animals↗

PubMedDate not supplied

Human herpesvirus-7 DNA in cerebrospinal fluid.

An infection by HHV-7 with presence of virus DNA in the spinal fluid was ascertained in a twenty five month old boy with an epileptic syndrome shortly after birth. The child was frequently admitted to hospital due to his basal disease and frequent bacterial infections. In the occasion of one of these hospital admissions for bacterial infections in conjunctiva, spleen and a lung, virological investigations were also carried out disclosing the presence of HHV-7 DNA in a sample of spinal fluid and of serum and the absence of DNAs from the other herpesviruses. The patient's monitoring for HHV-7 showed the presence of HHV-7 DNA in a sample of serum and in various samples of peripheral blood lymphocytes and saliva, but not in the cerebrospinal fluid sample successive to that positive for HHV-7 DNA. Forty seven days before the diagnosis of HHV-7 infection, the patient received a human gamma-globulin therapy which obscured the humoral response mounted against the virus by the host, so, whether the HHV-7 presence in the central nervous system was associated with a primary or a reactivated infection remained uncertain. The absence of detectable HHV-7 serum IgM antibody, however, suggests the HHV-7 DNA finding on the occasion of a virus reactivation rather than a primary infection. The virological data suggest that HHV-7 may have possibly reached the central nervous system in the course of a viremia. The absence of HHV-6 and HHV-7 antibodies, present in the patient's serum at a high level, support the integrity of the blood-brain barrier. A possible pathogenetic role of HHV-7 in the child's disease seems unlikely, since the epileptic syndrome was pre-existing.

Antibodies, Viral↗