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Biomedical subjects

C Andre

Publications and source records attributed to C Andre.

At least 91 records · Page 5Linked to original sources
PubMed1980

Anti-alprenolol anti-idiotypic antibodies bind to beta-adrenergic receptors and modulate catecholamine-sensitive adenylate cyclase.

Rabbit antibodies induced against alprenolol, a potent beta-adrenergic antagonist, bind to other antagonists, and, with less avidity, to catecholamine agonists. Anti-idiotypic antibodies were raised against the anti-alprenolol immunoglobulins. The anti-idiotypic antibodies specifically bind and agglutinate turkey erythrocytes; this is not observed for human agglutinate turkey erythrocytes; this is not observed for human or sheep erythrocytes, which are devoid of beta-adrenergic receptors. The anti-idiotypic antibodies compete with (--)-[3H]-dihydroalprenolol for binding on the beta-adrenergic receptors on purified turkey erythrocyte membranes. The binding to the membrane-bound receptors is prevented by preincubation of the anti-idiotypic antibodies with their immunogen, the antialprenolol immunoglobulins. The binding to the receptor is not merely passive: the anti-idiotypic antibodies stimulate basal adenylate cyclase activity [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] and enhance adenylate cyclase activation by catecholamine. These observations support the notion that antiidiotypic antibodies may constitute an "internal image" of the original antigen and may mimic its biological effects.

Adenylyl Cyclases↗
PubMed1980

Interaction between beta-adrenergic receptors and guanine nucleotide sites in turkey erythrocyte membranes.

beta 1-Adrenergic receptors from turkey erythrocyte membranes have been identified by specific binding of the radiolabeled antagonist (-)-[3H]dihydroalprenolol. These receptors are inactivated by the alkylating agent N-ethylmaleimide when occupied by beta-adrenergic agonists but not when occupied by antagonists or when unoccupied. A time-dependent decrease of the number of receptor sites is observed. Inactivation affects 45-60% of the sites, regardless of the agonist or N-ethylmaleimide concentration. The guanine nucleotides GTP and 5'-guanylyl imidodiphosphate effectively protect the receptors against agonist-mediated inactivation by N-ethylmaleimide. Protection by ATP necessitates a 100-fold higher concentration; 10 mM NaF is ineffective. The guanine nucleotide effect is reversible and occurs via interaction with N-ethylmaleimide-insensitive sites. These observations establish that guanine nucleotide sites interact with and caused structural modification of the agonist-occupied beta-adrenergic receptors in turkey erythrocyte membranes.

Allosteric Regulation↗
PubMed1979

Measurement of glycoprotein content and cell kinetics in preulcerous gastric mucosa.

In an attempt to evaluate the role of gastric mucosal defense factors in ulcerogenesis, we measured the levels of glycoproteins in the mucosa as well as mucosal cell turnover in the preulcerous phase and compared these parameters to the normal mucosa in the same animal. Ovalbumin-presensitized Praomys (Mastomys) natalensis were challenged in the gastric wall with ovalbumin and a gastric ulcer developed at the challenge site 3 days later as a result of a mucosal anaphylactic reaction. This model enabled us to study the events occurring at the site of a future ulceration. Gas-liquid chromatographic determination of mucosal glycoproteins showed that the normal and preulcerous mucosae had similar levels. Cell turnover, determined by [3H]thymidine incorporation, was stimulated as a result of the preulcerous anaphylactic reaction at 24 hours postchallenge whereas at 48 hours the values were not different from those obtained in controls. These results suggest that the pathogenesis of anaphylactic gastric ulcer involves a change in cell turnover but no changes in the production of gastric mucus.

Anaphylaxis↗
PubMed1979

A monoclonal macroglobulin with antinuclear activity.

Serum containing a monoclonal IgM protein from a patient with Waldenstroms' macroglobulinaemia gave intense immunofluorescent staining of kidney nuclei. The Fab mu fragments of this immunoglobulin were obtained. The IgM and Fab fragments reacted in vitro with kidney nuclei using unfixed cryostat sections of rat or mouse kidney. After treatment of the patient with chemotherapy, the monoclonal IgM disappeared, and no more antinuclear activity could be detected in the serum. The results strongly suggest that this IgM protein had antinuclear activity.

Adult↗
PubMed1978

Prevention of experimental anaphylactic ulcer by antigen prefeeding.

Studies were performed in animals to establish whether antigen prefeeding could present homocytotropic antibody synthesis and the induction of gastric ulcer resulting from mucosal anaphylaxis. A single digestive exposure to 1 or 10 mg ovalbumin induced a state of specific immunologic tolerance. Inhibition of the formation of specific reagins was shown by the study of mast cell degranulation. Tolerant animals presented a reduced incidence of gastric ulcer after subsequent mucosal challenge. These results are important for the development of methods of prevention and treatment of allergic diseases.

Anaphylaxis↗
PubMed1978

Study of human T and B lymphocytes with heterologous antisera. III. Immunofluorescence studies on tonsil sections.

Lymphoid cells from human palatine tonsils were identified on tissue sections by membrane or intracellular immunofluorescence (IF) staining. Used in an indirect technique, an anti-IgM and an anti-HTLA (human T lymphocyte antigen) antiserum gave complementary patterns of membrane IF, characteristic of the follicular organization. When serial sections were stained for each of the five classes, immunoglobulin-containing cells from all classes were found. Their relative frequencies were, in decreasing order: IgG: 61.6%; IgA: 17.3%; IgM: 12%; IgE: 7.5%; IgD: 1.6%. These differed from those of the gut-associated lymphoid tissue (IgA greater than IgG greater than IgM) and of the peripheral lymph nodes (IgG greater than IgM greater than IgA), but were close to those of mesenteric nodes. The absence of secretory component in tonsil was an additional difference from gut-associated lymphoid tissue and the relatively high proportion of IgE-containing cells, in the absence of recognized atopy, is another feature in common with mesenteric lymph nodes. Finally, slight differences between these results and those obtained on tonsil cell suspensions suggest that some degree of selection probably occurs during the isolation procedure.

Adolescent↗
PubMed1977

A random blood sugar diabetes detection survey.

In a co-operative study undertaken between various groups in the community, 3212 persons were screened at the Agricultural and Pastoral Summer Show in Christchurch. The mean glucose value was 88.4 mg/dl (4.9mmol/l) which roughly equates to 91 mg/dl (5.1mmol/l) plasma value. There was a standard deviation of 19.5mg/dl (1.08mmol/l) the 22.5 percentile was 63mg (3.5mmol/l), the 97.5 percentile was 125 (6.5mmol/l). One hundred and twenty persons of the total of 3212 were advised to contact their family doctors as a result of higher than normal blood sugar levels on the day. Twenty-five probable diabetics were diagnosed.

Adult↗
PubMedDate not supplied

Comparison of MultiMap and TSP/CONCORDE for constructing radiation hybrid maps.

Radiation hybrid (RH) map construction allows investigators to locate both type I and type II markers on a given genome map. The process is composed of two steps. The first consists of determining the pattern distribution of a set of markers within the different cell lines of an RH panel. This is mainly done by polymerase chain reaction (PCR) amplification and gel electrophoresis, and results in a series of numbers indicating the presence or the absence of each marker in each cell line. The second step consists of a comparison of these numbers, using various algorithms, to group and then order markers. Because different algorithms may provide (slightly) different orders, we have compared the merits of the MultiMap and TSP/CONCORDE packages using a data set of information currently under analysis for construction of the canine genome RH map.

Animals↗