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Biomedical subjects

J Drouet

Publications and source records attributed to J Drouet.

At least 19 recordsLinked to original sources
PubMed1991

Oxygen-induced modifications of benzodiazepine receptors and D2 dopamine receptors in the rat under hyperoxia.

Peripheral-type benzodiazepine Receptors (PBR) in the kidney and Central-type Benzodiazepine Receptors (CBR) in the cerebral cortex were not affected in rats exposed to chronic hyperoxia (85% O2, ATA, 6 days). Nevertheless, cortical CBR showed a significant decrease (29%) after hyperbaric hyperoxia (100% O2, 3.5 ATA, 2 h) in rats at a preconvulsive stage, with no concomitant alteration of kidney PBR. A similar down-regulation of striatal D2 dopamine receptors was noticed (27%)--after hyperbaric hyperoxia--without any modification of cortical PBR. On the contrary, an up regulation of liver PBR was obtained in the same conditions (20%). It is likely that receptors implicated in neurotransmission are particularly down regulated or altered under hyperbaric hyperoxia.

Animals↗
PubMed1979

Differential radiosensitivity of neurons and neuroglia of the hippocampus in the adult rabbit.

Adult rabbits were subjected to 4.5 Gy of whole-blody or brain alone gamma-irradiation, and their hippocampus was examined with the light and electron microscope. Pycnotic cells were found at the base of the granular layer of the dentate gyrus in the so-called subgranular zone, as soon as 3 h after irradiation, and were cleared up by active phagocytosis after 48 h. Some of these cells appeared as undifferentiated, whereas others were differentiating granule cells, and possibly immature neuroglia. The extent of cell necrosis was contingent upon the age of the animal, the oldest animal studied (27 months) showing only sparse lesion of that type. Astrocytes and microglia were responsible for the phagocytosis of dead cells. Another type of lesion was found in the nuclei of the mature granule cells and consisted of light spots which appeared 1 h after the irradiation and disappeared almost completely after 48 h. Pyramidal cells did not show any of these two lesions. It is concluded that the laterations in the electrical activity of pyrimidal cells, following irradiation, are at least partly due to lesions affecting the dentate gyrus. Radionecrosis in the subgranular zone is related to the presence of immature cells in this region.

Age Factors↗
PubMed1979

Simultaneous occurrence in the same serum of hepatitis B surface antigen and antibody to hepatitis B surface antigen of different subtypes.

The simultaneous occurrence of hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) of different subtypes in the serum of a hemodiaylzed patient was studied. The w(a) subdeterminants were involved. The HBsAg belonged to the ayw3 subtype, and the anti-HBs exhibited monospecific anti-w2 activity. Both the HBsAg and the anti-HBs were detectable by counterelectrophoresis (CEP). The specificity of the antibody was demonstrated by CEP in tests against 128 sera containing HBsAg of 12 different subtypes and in absorption experiments with eight sera containing HBsAg of eight different subtypes, as well as by radioimmunoassay in the liquid phase. The monospecific antibody was selectively directed against the w2 subdeterminant of the adw2 subtype and was designated anti-w2.

Absorption↗
PubMed1978

IgG versus albumin for measurement of plasma volume in normal and hypertensive men.

Labeled IgG was evaluated versus labeled albumin for measurement of plasma volume, to see whether it would give a smaller initial dilution volume (indicating a smaller premixing extravascular loss of label) and a smaller difference between initial dilution volume and dilution volume at time 10 min (indicating a negligible extravascular loss in the first 10 min after mixing). IgG was found to have a lower transcapillary escape rate than albumin (P less than 0.01) in eight normal volunteers and in eight hypertensive subjects, hypertension being associated with an increased transcapillary escape of both proteins. Despite this, the dilution volumes obtained were indistinguishable and the need for a correction through a retropolation procedure was the same with both proteins. Albumin and IgG dilution volumes were highly correlated in 21 subjects (r=0.977) so that use of labeled IgG is a proper alternative to use of labeled albumin for plasma volume determination. However, since IgG brings no consistent advantage, labeled albumin remains the best available tracer for that purpose.

Blood Pressure↗
PubMed1978

Hepatitis B in children. II. Study of children born to chronic HBsAg carrier mothers.

A survey of 4,452 pregnant women taken to find hepatitis B surface antigen revealed 28 asymptomatic chronic carriers. At birth, 16 of 17 infants studied were negative for HBsAg, whereas anti-HBc was present in all patients at a titer similar to that of the mother. Twelve children were followed for 6 to 18 months. In four of them, HBsAg remained negative and anti-HBc titers progressively decreased and were undetectable when tested after the age of 6 months. In eight infants, HBsAg became positive after an average time of 48 days. Elimination of HBsAg occurred in seven infants; five of them had clinical and biological manifestations of mild hepatitis. Sequential determinations of total complement and C components in three patients of the latter group showed dperession of complement at the time of appearance of clinical manifestations. In the patient who became an HBsAg carrier as well as in three infants who remained HBsAg negative, no decrease in complement titers was observed. These results indicate that vertical transmission from carrier mothers can occur in a low prevalence area and that neonatally infected children are capable of active elimination of HBV.

Antibodies, Viral↗
PubMed1978

[HBs antigen screening with Groupamatic. Inhibition of passive hemagglutination and latex test].

Some agglutination tests for HBs Ag and anti-HBs detection may be easily automated. Reverse hemagglutination, needing a lengthy incubation and several steps to carry out is unfit for Groupamatic, but hemagglutination inhibition and latex agglutination may be used. Hemagglutination inhibition using selected human red cells (ORh+) coated with cesium chloride purified HBs Ag, has been now routinely used at the C.N.T.S. with visual reading for almost 2 years. Negative and positive controls are necessary. The anti-HBs serum utilized has to be checked daily to get sensitive detection. Every new batch of coated red cells (valid 4 to 6 weeks) is checked in microtiter plates in the laboratory, before being used on Groupamatic. Both positive and dubious results are systematically retested in RIA. We found only 0,5% of false positive. The sensibility of the test compared favourably with other third generation test as reverse hemagglutination. It was close to the results obtained with radio-immuno-assay or enzyme-immuno-assay and it was more sensitive than counter-immuno electrophoresis. 65,472 samples were tested in parallel: we were able to detect 97% of HBs Ag detected by RIA. False negative results were less than 1 per 10 000 and may be avoided by using citrated solution for the anti-HBs serum dilution (suppression of auto-agglutination of the red cells). Antigex TG (the most active batch of latex coated with guinea pig, anti-HBs antibody) made by Pfizer, gave good results on Groupamatic and automatic reading was possible. But more results are necessary using various batches, before to recommend such reagent.

Autoanalysis↗
PubMed1977

Detection of hepatitis B antigen in circulating immune complexes in acute and chronic hepatitis.

By using polyethylene glycol precipitation at low concentration (PEG test) and the radiolabeled C1q binding test, immune complexes were detected sera from acute (23/28) and chronic (28/32) hepatitis patients, hemodialyzed patients with chronic hepatitis B surface (HBs) antigenemia (7/19), and asymptomatic HBs antigen carriers (2/11). After treatment of PEG precipitates with acidic pH, heating, or proteolytic enzyme (protease), electroimmunodiffusion or radioimmunoassay revealed the presence of HBs antigen or antibody in dissociated immune complexes in sera from several acute and chronic hepatitis patients. Electron microscopy showed immune complexes of HB virus in 9 of 12 PEG precipitates obtained from PEG-test-positive sera; these 9 precipitates were from patients with acute or chronic hepatitis and the other three from chronic HBs Ag carriers. Free HB virus particles were observed after protease digestion of PEG precipitates. Neither immune complexes nor virus particles were seen in precipitates from PEG-test-negative but HBs-Ag-positive sera from chronic carriers.

Acute Disease↗
PubMed1977

Screening of HBs antigen and detection of corresponding antibodies on groupamatic equipment.

The widespread utilization of Groupamatic equipment for routine immunohaematological tests has increased the demand for serological procedures that can be performed with this machine. We describe the test method which was developed and with which the detection of HBs antigen has now been carried out routinely for 1 year. It is an automated haemagglutination inhibition reaction which is called GIPHA (Groupamatic inhibition of passive haemagglutination). The sensitivity corresponds to 2 CNTS units, the antigen weight for 1 unit being from 1 to 4 ng. The reproducibility is good; the percentage of false positive reactions is about 0.5% and that of technical problems 0.7%. The additional advantages of the machines are numerous, among which we have the possibility of 11 other simultaneous reactions. One of them is the detection of antibodies against HBs antigen, which is a passive haemagglutination test called PHAG (passive haemagglutination on Groupamatic).

Antibodies↗
PubMed1976

[Functional study of cultured bone cells].

Osseous cells in culture synthesize and excrete glycosaminoglycans, collagen and alkaline phosphatases, revealed by the classical histochemical reactions. Observation of the living cells iwth the polarizing microscope, after a five day-culture, reveals the presence of micro-crystals of mineral salts only at the level of cells and cellular groupings.

Alkaline Phosphatase↗
PubMed1976

[A technic for culturing bone cells].

A technique of osseous cells culture has been perfected through discontinuous enzymatic digestion of young Mice prietal bones and using a chemically defined medium buffered by means of hepes. The cultural characteristics observed seem to correspond to those of osteogenic cells.

Animals↗
PubMed1975

[Evaluation of various radioimmunological techniques for the detection of antigen HBs].

The different radioimmunoassay technics routinely used for detection of HBs Antigen are Ausria I, Ausria II, RIA and CLB/RIA. Classification of these techniques either liquid or solide phase, is realized by nature of the tracer (Antigen or Antibody radioiodinated). The sensitivity and the specificity are presented as the comparison with other reactions. There is no significative difference on 1089 tested samples between Ausria I and RIA. The percentage of false positives in RIA or CLB/RIA reactions is 1.5% when the incubation is at 20 degrees C and 1% when it is at 37 degrees C. Advantages, disadvantages, cost prices, automation and possibility of computer treatment are discussed. The utilization of reference sera is proposed and the problem of the utilization en France of the radioactive products is approached.

Hepatitis B Antigens↗
PubMed1975

Platelet indirect radioactive Coombs test. Its utilization for PLA1 grouping.

A platelet indirect radioactive Coombs test (PIRC) has been described. The technique for purification and labelling the antiglobulin has been precised. This test allowed the typing of platelets in the PLA system by using an absorbed serum from a mother of a thrombocytopenic child. Six other families of neonatal thrombocytopenias were tested. In three of them, the mothers were found PLA1 negative (PLA2, PLA2). Among a panel of 93 platelets, two (0.022) were found PLA1, negative. This PIRC test has many advantages compared to other tests such as platelet complement fixation, assay for blocking antibodies or antiglobulin consumption: it gives objective and quantitative results and is highly reproducible; anticomplementary serum may be tested.

Animals↗
PubMed1975

HBs antigen in human plasma fractions.

Therapeutic fractions were obtained by fractionating human plasma containing HBs antigen, by the Cohn ethanol technique modified by Nitschmann. Plasmas with various HBs antigen titers were selected. The antigen was sought in each fraction by the techniques of counterelectrophoresis and radioimmunological detection in liquid phase. With the exception of very pure albumins, all fractions were found to contain the HBs antigen, though in variable proportions. A technique for the purification of albumin, applicable on an industrial scale, is proposed. It makes it possible to obtain an albumin fraction in which the HBs antigen cannot be detected by the most sensitive techniques, even starting with a plasma which is very rich in HBs antigen (titer 1/64 by counterelectrophoresis).

Blood Coagulation Factors↗