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Biomedical subjects

G Perret

Publications and source records attributed to G Perret.

At least 73 records · Page 4Linked to original sources
PubMed1982

Failure of in vivo and in vitro resialosylation of VCN-desialylated erythrocytes in mammalian and non-mammalian species: evidence from agglutination studies with peanut-agglutinin.

1. In distinction to mammalian erythrocytes, splitting of sialic acids of non-mammalian erythrocytes (chicken and newt) by Vibrio cholerae neuraminidase (VCN) does not lead to a dramatic decrease in their viability. 2. One of the possibilities to explain this discrepancy is the ability of chicken and newt desialosylated erythrocytes to repair the enzymatic injury. 3. To test this hypothesis we used the property of peanut agglutinin (PNA) to agglutinate desialosylated erythrocytes. 4. Desialosylated erythrocytes of all the species tested remain PNA-agglutinable throughout their whole life time in the blood stream. The absence of effect of VCN on chicken and newt erythrocytes is therefore not due to their resialosylation.

Animals↗
PubMed1982

Effects of cimetidine on thyroid hormones.

Short-term administration of the H2-antagonist cimetidine (400 mg three times/day for 5 days) was performed in eight healthy male volunteers and its effects on both thyroid hormone levels and on hypophyseal hormone release induced by acute hypoglycaemia and TRH were tested. Absolute values of basal and post-TRH serum T3 were decreased by treatment, while basal and stimulated serum rT3 and T4 levels were not altered significantly. Cimetidine administration did not change the hormone release induced by acute hypoglycaemia but significantly enhanced the prolactin and TSH responses to TRH. Our results suggest that cimetidine administration can modify the peripheral metabolism rather than the secretion of thyroid hormones.

Adult↗
PubMed1982

[Study of the interaction between desialylated erythrocytes and Kupffer cells using perfusion of liver in situ].

Desialylated erythrocytes, when perfused in mice liver in situ, were shown to be sequestered. This sequestration was inhibited by dihydrocytochalasin B and a neoglycoprotein: N-Acetylgalactosaminyl-albumin. Our results confirm that, under physiological conditions, the recognition of desialylated erythrocytes appear to be related to the presence of N-Acetylgalactosamine or galactose receptor on the surface of Küpffer cells.

Animals↗
PubMed1981

[Effect of ethanol, acetazolamide, and cyclophosphamide on protein and lecithin concentrations in broncho-alveolar liquid film of mice].

An original approach to reveal in Mice, the impact of some xenobiotics and drugs on the alveolo-capillary barrier...(ethanol, acetazolamide, cyclophosphamide is described. Drugs are injected I.P. during five days in subacute dose size. Concentrations of lecithines and proteins are settled in bronchoalveolar lavage fluids from animals having or not undergone an important blood loss just before the lavage.

Acetazolamide↗
PubMed1981

In vivo ageing of human erythrocytes and cell-surface labeling by D-galactose oxidase and sodium borotritide.

Young and old, human erythrocytes, separated in vitro according to their age in vivo, were radioactively labeled at the cell-surface D-galactosyl and 2-acetamido-2-deoxy-D-galactosyl residues by treatment with D-galactose oxidase, followed by reduction with sodium borotritide. The labeling was quantitatively determined for each type of erythrocyte by measuring the molar amounts of borohydride necessary for the complete reduction of the oxidized residues. The number of surface residues per blood-group A+ erythrocyte was found to be 37.6 +/- 1.8 x 10(6) (n = 8) for young, 21.8 +/- 4.9 x 10(6) (n = 8) for old, and 24.8 +/- 6.4 x 10(6) (n = 8) for middle-aged erythrocytes, indicating a significant decrease of the residues during ageing.

ABO Blood-Group System↗
PubMed1981

Decrease of carbohydrate in membrane glycoproteins during human erythrocyte ageing in vivo.

Membrane glycoproteins from young human erythrocytes and erythrocytes aged in vivo were fractionated by gel filtration. Three major groups of glycoproteins were obtained. The neutral hexoses and sialic acid contents of each group of glycoproteins from the old cells were found to be significantly reduced by comparison to the values found in the glycoproteins of the young cells. Thus, the previously observed decrease in neutral hexoses and in sialic acid contents of the full erythrocyte membrane during in vivo ageing does not affect only one particular group of glycoproteins but each of the groups of glycoproteins tested, including the major glycoproteins of the erythrocyte membrane, that is to say glycophorins. It is shown in addition, that the previously observed decrease per cell of the surface galactose and N-acetylgalactosamine residues of the ageing erythrocyte affect several groups of membrane glycoproteins including band 3, PAS-1, PAS-4 and PAS-3. The physiological significance of these experimental data is discussed.

Chromatography, Gel↗
PubMed1981

Further purification of gastrozymin and spectrum of activities.

Gastrozymin differed from secretin in several chromatographic and solubility characteristics. However, it showed a spectrum of activities which resembled those of secretin, including stimulation of pepsin, hepatic bile secretion, and pancreatic bicarbonate secretion. This study revealed differences in the quantitative ratios of these activities when induced by secretin or gastrozymin. In particular, if the ratio of the stimulation of pepsin secretion to that of pancreatic juice bicarbonate was 1:1 for secretin, it was 4:1 for gastrozymin. Further purification will show whether all these effects are induced by one molecule or by several peptides. It will also determine whether there is a structural relationship between gastrozymin and secretin or its precursor(s).

Animals↗
PubMed1981

[Interest of the determination of reference values for the monosaccharide composition of the human erythrocyte membrane (author's transl)].

The carbohydrate composition of the human erythrocyte membrane was just established ten years ago. Carbohydrates have crucial functions in the membrane structures and the determination of this composition may have an important semeiological signification. In this way, reference values are necessary. The existence of possible variations of the composition with two physiological parameters: the groups in the ABO system and the age of erythrocytes have been investigated and are reported. Their repercussion on the determination of reference values is discussed.

Blood Group Antigens↗
PubMed1981

[Thyroid disorders during sarcoidosis (author's transl)].

A clinical, scintigraphic and hormonal study of the thyroid was performed in 50 patients with intrathoracic sarcoidosis. The patients were divided into two groups: T - : n = 32, no thyroid abnormality; T +, 18 cases, with thyroid disorders (9 moderate diffuse goitres, 2 thyroid nodules, 7 nodular goitres). All had normal T4, T3 and TSH levels, except one patient with Graves's disease. Scarce sarcoid granulomas were found in 3 out of 4 patients who underwent thyroidectomy. Dissemination, activity, type of sarcoid thoracic involvement were not different in the two groups. In contrast, T + group had higher seric IgG levels than T - group (p less than 0,05). The association of sarcoidosis and goitre is not fortuitous but thyroid enlargement and sarcoid diffusion do not seem interrelated. Auto-immune thyroiditis seems unlikely in our cases, according to the low frequency of thyroid auto-antibodies. We discuss the possible role of seric immunoglobulins in the constitution of thyroid hypertrophy with or without hyperthyroidism in sarcoidosis.

Adult↗
PubMed1980

Individual variations of the seven carbohydrate components of human erythrocyte membrane during aging in vivo.

The contents of fucose, mannose, galactose, glucose, 2-acetamido-2-deoxy-D-glucose and -D-galactose, and sialic acid, when the results were expressed as nmol per mg of membrane dry-weights, were found to be significantly lower in the membranes of old erythrocytes than in the membranes of young ones. No significant difference was found between young and old membranes when the compositions were expressed as residues per one hundred carbohydrate residues, suggesting that a homogeneous decrease of the carbohydrate moieties may occur during aging in vivo.

Erythrocyte Aging↗
PubMed1980

The role of T-agglutinin in the disappearance of erythrocytes artificially aged by desialylation.

The chance discovery of two mouse strains, one with and one without a high presence of serum T-agglutinin, permitted the investigation of the role of this antibody in the disappearance of desialylated erythrocytes, which may be regarded as a model for ageing. The proportional relationship between the quantity of sialic acid removed and the diminution of half-life is not affected by the presence or absence of T-agglutinin. Opsonization by T-agglutinin would therefore appear to be an improbable mechanism. Other possible theories are discussed.

Agglutinins↗
PubMed1979

Carbohydrate content of human erythrocyte membrane. Variations with ABO-blood group.

The study of the carbohydrates of human erythrocyte membranes has been mainly focused on their glycopeptidic and glycolipidic complexes. Modifications of these carbohydrates have been described in subjects with various pathological states. In order to characterize possible changes of the glycopeptides, or glycolipids obtained from erythrocyte membrane in various pathological situations, the determination of the carbohydrate content of the whole membrane appeared a necessary preliminary. This study concerns the determination of the normal values of the main carbohydrates of whole human erythrocyte membranes, with respect to their blood group. Erythrocyte membranes were prepared from donors of the four ABO blood groups. After acidic hydrolysis, the contents of fucose, mannose, galactose, glucose, glucosamine, galactosamine and N-acetylneuraminic acid in each blood group were determined and compared with one another. The galactosamine content of A, B and AB erythrocyte membranes is significantly higher than that of the O-erythrocyte. For galactose, the differences are significant for the following pairs: A/O; B/O; AB/O; A/B; A/AB. Significant differences in the mannose contents of O-erythrocytes and A, B and AB erythrocytes have also been found. This result suggests that a basic difference, in the core of the oligosaccharide chains, may exist between O and A, B, AB erythrocyte membranes.

ABO Blood-Group System↗
PubMed1979

[TRH response in 53 patients with chronic alcoholism (author's transl)].

A study of thyroid function was undertaken in 53 patients with chronic alcoholism the following tests were performed: T3 RIA, T4 RIA, T3 test and I.V. TRH-test. The patients were divided into 3 groups according to the degree of liver injury: histologically documented fibrosteatosis (group 1), cirrhosis (group 2); group 3 consisted of severe cirrhosis with coagulation defects precluding liver biopsy. 32 healthy subjects served as controls. Free thyroxine index was normal in the 3 groups of patients; on the contrary, serum T3 RIA was significantly reduced in the 2nd and the 3rd group. The decrease of T3 correlated with the degree of hepatocellular failure. TRH test was almost always normal. If patients are separated into two groups according to their circulating T3 levels, it appears that subjects with low T3 show a TRH-induced increase in TSH lower than in the other group, but not significantly different from normal subjects, suggesting an inadequate hypothalamic reactivity.

Adult↗
PubMed1978

[Comparison of the survival of desialylated erythrocytes and demonstration of the presence of T-agglutinin in rabbits and ducks].

Rabbit as well duck erythrocytes desialization leads to a dramatic decrease of their survival time. Rabbit erythrocytes are trapped transiently by the liver ; in contrast splenic uptake is gradual. Serum from the two species contains a T-agglutinin directed against autologous desialyated erythrocytes. In the two cases, this T-agglutinin is from the IgM class and its immunodominant sugar is galactose in the beta configuration.

Agglutinins↗
PubMed1978

Effects of chronic alcoholism on the pituitary-gonadal function of women during menopausal transition and in the post menopausal period.

The hypothalamo-pituitary gonadal function was evaluated in eleven chronically alcoholic menopausal women by measurement of basal serum oestradiol, FSH, LH and prolactin, followed by LHRH-TRH test and administration of clomiphene citrate. All patients had hepatic damage, fibrosteatosis or cirrhosis. Two subgroups have been isolated according to urinary and serum estrogen levels: seven patients with urinary estrogen output less than 14 microgram per 24 h and plasma oestradiol less than 40 pg per ml were considered as post menopausal women: basal values of FSH and LH and their response to LHRH did not differ from that observed in normal menopausal women; clomiphene citrate induced a significant suppression of FSH and LH blood levels. Four women with urinary estrogen output greater than 14 microgram per 24 h and plasma oestradiol greater than 40 pg per ml were considered in menopausal transition. Their basal and post LHRH-FSH blood levels were lower than in the control group. These results suggest a normal hypothalamo-pituitary-gonadal axis at least in the post menopausal alcoholic women.

Aged↗