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Biomedical subjects

C Desgranges

Publications and source records attributed to C Desgranges.

At least 127 records · Page 7Linked to original sources
PubMed1983

Cytomegalovirus isolations from cell cultures derived from Epstein-Barr virus-associated nasopharyngeal carcinoma.

Cytomegalovirus (CMV) was isolated in cell cultures derived from 2 of 11 nasopharyngeal carcinoma (NPC) biopsy specimens from North African patients. All these cases were Epstein-Barr virus (EBV)-associated NPC. Morphologic cytopathic changes and viral replication not associated with EBV were observed after 2 months in culture. Virus identification was achieved by immunofluorescence studies, and cell culture antigens were tested by the use of complement fixation and indirect hemagglutination. All these NPC patients had been infected by herpes simplex virus, varicella-zoster virus, and CMV, but the antibody titers determined by complement fixation and immunofluorescence were normal. CMV, which is not associated with this cancer, could nevertheless favor carcinogenesis in facilitating fusion between epithelial cells and EBV-positive lymphocytes.

Adolescent↗
PubMed1983

[Complexes of "pancreatic elastase-seric inhibitors" in swine: their behavior in the presence of homologous aortic elastin].

The present paper deals with the particular behavior of the complexes formed between pancreatic elastase and seric inhibitors in the Pig, when they were set in contact with homologous elastin. The previously known values of dissociation constants of alpha 1-antiprotease-elastase and alpha 2-macroglobulin-elastase complexes indicated they were very stable and almost irreversible. Nevertheless, our results suggest that, when the overall complexes between porcine pancreatic elastase and seric inhibitors were isolated in non drastic conditions, they might develop an elastolytic activity against elastin fibers. This result is important as regards atherosclerosis--in Human--where a destruction of elastin is involved at a early stage of the disease.

Animals↗
PubMed1983

[Demonstration of elastinolytic activity in blood or plasma].

The complexes between "elastases" and their seric inhibitors (a. 1. AP and a2. M) which could be formed in the blood, are exhibited in vitro: after incubation of serum or plasma with 125iodine labelled elastin at pH = 6, followed by extensive washing, pH was increased from 6 to 8.6: labelled peptides are released in supernatant.

Animals↗
PubMed1982

The human blood platelet: a cellular model to study the degradation of thymidine and its inhibition.

Intact platelets catabolize extracellular thymidine into thymine. Studies of the concentration dependent degradation of thymidine by intact platelets indicate a Michaelis mechanism with an apparent Km of about 0.12 mM and a Vmax of 2.5 nmoles/min for 3 X 10(8) platelets. This degradation process is inhibited by various nucleosides, pyrimidine bases and C-5 or C-6 substituted uracils. Cytidine, deoxycytidine, adenosine and deoxyadenosine seem to inhibit thymidine degradation by reducing the intracellular transport of thymidine. Uridine inhibits both the thymidine transport and the activity of the phosphorolytic enzyme, thymidine phosphorylase (EC 2.4.2.4). Some substituted uracils are specific inhibitors of thymidine phosphorylase activity. 6-Amino-5-bromouracil, the most active of them, either with acellular extracts or purified thymidine phosphorylase, is also the best inhibitor of thymidine degradation in intact human platelets. Platelets constitute a new model to study the efficiency of specific inhibitors on thymidine catabolism in an 'human intact cell' which contains only one pyrimidine nucleoside phosphorylase, the thymidine phosphorylase.

Biotransformation↗
PubMed1982

Detection of Epstein-Barr viral DNA internal repeats in the nasopharyngeal mucosa of Chinese with IgA/EBV-specific antibodies.

Fifty-six South Chinese individuals exhibiting IgA antibodies to EBV for 18 months and presenting nasopharyngeal abnormalities were biopsied. Four nasopharyngeal carcinomas, two at a very early stage, were detected. In 14 further individuals, without clinical or histopathological evidence of tumor, EBV/DNA internal repeats and/or EBNA were detected in the biopsied mucosae. The presence of IgA/EBV antibodies and/or EBV markers in the nasopharyngeal mucosa may characterize pre-cancerous conditions.

Adult↗
PubMed1981

Catabolism of thymidine in human blood platelets: purification and properties of thymidine phosphorylase.

A pyrimidine nucleoside phosphorylase was partially purified from human blood platelets. The purified enzyme, as well as crude enzyme preparations, catalyses the phosphorolysis of thymidine and deoxyuridine, but not of uridine, and is able to catalyse direct pentosyl transfer from these deoxyribonucleosides to uracil or thymine; this enzyme has the properties of a thymidine phosphorylase. It has a molecular weight of about 110,000 and is composed of two identical subunits; it is phosphate dependent, has a maximal activity at a pH value of 5.7, and an isoelectric point of 4.4. This enzyme was mainly of cytoplasmic origin. Although platelet thymidine phosphorylase could promote the degradation or synthesis of thymidine, intact platelets degraded thymidine but were not able to synthesize thymidine from thymine. Blood platelets may play an important role in the degradation of plasma thymidine.

Blood Platelets↗
PubMed1981

A specific one step method for the isolation of pancreatic elastase; its use to characterize aortic elastase.

Elastase was purified from an acetone-ether powder of porcine pancreas by a one step affinity chromatography procedure on IgG-Sepharose 4B. The IgG was derived from a rabbit immunized with porcine pancreatic elastase and was itself isolated by affinity chromatography on elastase immobilized on the same matrix. The column was calibrated with a known elastase preparation under standardized conditions. Direct isolation of elastase from pancreatic extracts yielded approximately 90 mg from two pancreas. The enzymatic activity and electrophoretic migration in SDS-polyacrylamide gel of the purified elastase were equal to those of the purest commercially available enzymes. Application of this method to aorta of young pigs suggests the presence of active elastase in the aorta.

Animals↗
PubMed1980

[Anti-elastase of human pancreas: preparation and biological interest].

The present paper deals with the use of a new technique in type II human pancreatic elastase studies based on the use of a reversible immune-adsorbent which provides a unique specificity. According to the type of ligand linked on activated Sepharose, the elastase or its antibody in Rabbit could be obtained, in very pure form, in a one step process. The anti-human pancreatic elastase II, which specifically inhibits the enzyme, may be used in therapy whenever the elastase-inhibitor system becomes unbalanced.

Animals↗
PubMed1980

Persistence of human adenovirus 5 in human cord blood lymphoblastoid cell lines transformed by Epstein-Barr virus.

Lymphoblastoid cell lines derived from human cord blood leukocytes were persistently infected with human adenovirus 5. These cell lines expressed the Epstein-Barr nuclear antigen, but no other Epstein-Barr virus-related antigen. They continually produced infectious adenovirus 5 particles, but this production could be inhibited by the presence of specific neutralizing antibody to adenovirus 5. This suggests that the persistent infection might be due to the continual reinfection of susceptible cells by complete virus.

Adenovirus Infections, Human↗
PubMed1979

Epstein-Barr virus specific IgA serum antibodies in nasopharyngeal and other respiratory carcinomas.

In order to better understand the relationship between IgA and IgG antibodies to Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC), we analyzed 230 NPC sera but also a series of sera from patients with other carcinomas selected for their high EBV/IgG antibody titres. We were surprised to find that 21 out of 46 sera from bronchopulmonary carcinomas (BPC) and 6 out of 7 carcinomas of nasal fossae were IgA anti-VCA positive, and 9 BPC sera and 5 nasal fossae sera were also positive for IgA and anti-EA. Bronchial undifferentiated small-cell carcinomas may represent a particular group associated with high EBV profile.

Antibody Specificity↗
PubMed1979

DNA polymerases of anucleated cells. Isolation and characterization of two DNA polymerases from human platelets.

Two different DNA polymerases have been purified and characterized from human platelets. In the mitochondrial fraction a unique activity of the polymerase gamma type has been found. The same enzyme is found in the extramitochondrial supernatant. A second DNA polymerase, called 'cytoplasmic' DNA polymerase has been found in the 10000 x g supernatant of human platelets. The following properties of the latter DNA polymerase from human platelets are identical to those of DNA polymerase alpha from normal cells: DEAE-cellulose and phosphocellulose chromatography, size, thermal stability, phosphonoacetic acid and ethidium bromide inhibition. However, some of its properties, like high resistance to N-ethylmaleimide and the lack of DNA polymerization using synthetic RNA primers, are those of DNA polymerase beta.

Blood Platelets↗
PubMed1979

In vitro transforming activity of Epstein-Barr virus (EBV). II. Differences between M81 and B95-8 EBV strains.

Lymphocytes from 38 human cord blood and 9 adult circulating blood were aliquoted and infected in parallel either with the B95-8 EBV strain (produced by cotton-top marmoset lymphocytes transformed by EBV originating from an infectious mononucleosis line) or with the M81 EB virus (produced by callithrix jacchus marmoset lymphocytes transformed by EBV originating from a nasopharyngeal carcinoma (NPC) derived line). Significant differences were observed in the lymphoblastoid lines obtained and involved cell morphology, cell growth and synthesis of viral antigen. Cord blood lymphocytes infected with M81 virus resulted in lymphoblastoid lines where EA and VCA synthesis and production of virions took place, whereas this was not observed in B95-8 induced lines.

Adult↗
PubMed1978

[DNA polymerases in human platelets].

Human platelets have two DNA polymerases. In the mitochondrial-free cytoplasm we have found a DNA polymerase gamma and another DNA polymerase very closely related to the polymerase alpha from animal cells. In the mitochondria only the gamma activity is present.

Blood Platelets↗