PubMed Health⌕ Search

Biomedical subjects

J C Costa

Publications and source records attributed to J C Costa.

12 recordsLinked to original sources
PubMed1979

Determination of lecithin:cholesterol acyltransfer in mouse plasma and the influence of mercaptoethanol and sulphydryl blocking agents on its activity.

1. The cholesterol esterifying activity in mouse plasma has been identified as lecithin:cholesterol acyltransferase (LCAT) on the basis of stoichiometric data, predominant transfer of polyunsaturated fatty acids, wide pH optimum and inhibition of esterification by phospholipase A2 and sulphydryl blocking agents. The esterifying activity differed from that present in plasma of man, rat and other species since it was partially inhibited by mercaptoethanol and other thiols. 2. Stoichiometric correlations between unesterified cholesterol, lecithin and lysolecithin were not exact, suggesting possible involvement of other enzymes in the overall esterification process during in vitro incubation of mouse plasma. 3. The initial rate of cholesterol esterification was determined by in vitro incubation of mouse plasma, whose cholesterol had been labelled by prior in vivo injection of 3H-mevalonic acid. The mean rate was 281 +/- 74 nmol/ml/hr (mean +/- S.D., n = 12) and correlated with unesterified cholesterol concentration (r = 0.73, P less than 0.01).

Animals↗
PubMed1979

Plasma lipid concentrations for some Brazilian lizards.

1. Plasma concentrations of cholesterol, cholesteryl esters, phospholipids and triglycerides were determined for ten species of Brazilian lizards, Iguana iguana, Tropidurus torquatos and T. semitaeniatus (Iguanidae), Tupinambis teguixin, Ameiva ameiva and Cnemidophorus ocellifer (Teiidae), Mabuya maculata (Scincidae), Hemidactylus mabouia (Gekkonidae), Amphisbaenia vermicularis and Leposternon polystegum (Amphisbaenidae). 2. Considerable inter- and intra-species variations in plasma lipid concentrations were observed. 3. The percentage of total cholesterol esterified and the individual phospholipid composition of plasma were relatively constant for each species. 4. Over 60% of the cholesteryl esters present in plasma from three species each of iguanid and teiid lizards were polyenoic.

Animals↗
PubMed1979

Meyenburg complexes of the liver and bile cysts as a consequence of hepatic ischemia.

Meyenburg complexes and simple bile cysts are described in a patient having polyarteritis nodosa with involvement of the intrahepatic arterial tree. Similar lesions are found in the liver of monkeys subjected to experimental occlusion of the peripheral hepatic arterial tree. It is proposed that a pathogenetic mechanism conducive to the formation of Meyenburg complexes may be hepatic ischemia.

Animals↗
PubMed1979

Latent infection by herpes simplex virus.

The experimental evidence contributing to the understanding of herpes simplex virus latent infection has been reviewed. The site of residence of the virus during silent periods of the disease appears to be, in the majority of instances, the sensory ganglion innervating the territory of prime infection. Little is known about the factors that bring about latent infection, maintain it, and regulate the production of infectious particles that cause recurrences.

Adolescent↗
PubMed1976

Persistence of the viral genome in interferon-treated cells infected with oncogneic or nononcogenic viruses.

In AKR mouse cells chronically infected with a murine leukemia virus, treatment with interferon for nine days resulted in sustained inhibition of extracellular production of murine leukemia virus but no inhibition of viral intracellular p30 antigen or of reverse transcriptase. Removal of interferon resulted in rapid reversal of these effects. Interferon-treated mouse L-cells were infected with high multiplicities of vesicular stomatitis virus or herpes simplex virus type 1. Infectious virus and intracellular viral antigen were rapidly eliminated from the interferon-treated cultures infected with herpes simplex virus. In cultures infected with vesicular stomatitis virus, titers of virus remained low in interferon-treated cells, but after about two weeks they rose rapidly and the cultures were destroyed. If treatment with interferon was reinstituted as late as nine days after primary infection, infectious vesicular stomatitis virus was eliminated, and there was no evidence for survival of the viral genome in these cultures. In the cultures infected with murine leukemia virus, inhibition of production of virus by treatment with interferon was possible, but the viral genome was not eliminated. In cells acutely infected with vesicular stomatitis virus or herpes simplex virus, however, the viral genomes were apparently eliminated from cultures treated with interferon.

Animals↗
PubMed1975

Role of Fc receptors in herpes simplex virus infection.

It is suggested that Fc receptors which appear on the surface of cells infected by herpes-simplex virus confer a biological advantage on the virus--perhaps by binding immunoglobulin molecules or antigen-antibody complexes on the cell surface, thus blocking viral antigenic sites, or by consuming antibody directed at surface viral antigen or by modifying replication of the virus.

Antibodies, Viral↗