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Biomedical subjects

G Pelletier

Publications and source records attributed to G Pelletier.

At least 325 records · Page 18Linked to original sources
PubMed1991

Effect of human growth hormone-releasing factor and(or) thyrotropin-releasing factor on growth, carcass composition, diet digestibility, nutrient balance, and plasma constituents in dairy calves.

Sixty male dairy grain-fed calves, raised from 70 to 223 kg BW in individual crates, were used in a 2 X 2 factorial arrangement to determine the effect of administration of human growth hormone-releasing factor (1-29)NH2 (GRF) and(or) thyrotropin-releasing factor (TRF). Calves received twice-daily s.c. injections of .9% NaCl (control), GRF (5 micrograms/kg BW), TRF (1 micrograms/kg BW) or GRF (5 micrograms/kg BW) plus TRF (1 micrograms/kg GTRF). Average daily gain and days on feed were not affected by treatments, but TRF treatment increased (P less than .05) total intake of dry matter (DM) and feed conversion ratio: 3.00, 3.02, 3.08, and 3.22 kg DM/kg weight gain for control, GRF, TRF, and GTRF, respectively. During two 7-d periods, after 66 and 75 d of treatment, feces and urine were collected from 40 calves (5 per treatment per period). Treatment with GRF increased (P less than .05) digestibility of DM, nitrogen (N), and energy and tended (P less than .20) to increase N retention. At slaughter, withers height was increased (P = .05) by GRF and carcass length was increased (P less than .05) by TRF. Pituitary and liver weights were increased (P less than .05) by TRF. The combination of GRF and TRF slightly increased (P less than .10) protein content and decreased (P less than .05) fat content of the 9-10-11th rib section. After d 1, GRF treatment chronically increased (P less than .05) insulin concentrations and also increased (P less than .10) IGF-I concentrations on d 29 and 57. In summary, chronic treatment with GRF and(or) TRF did not improve growth or efficiency, although GRF increased digestibility of DM, N, and energy and the GRF plus TRF combination resulted in slightly leaner carcasses.

Animals↗
PubMed1991

[Long-term outcome of alcoholic patients after a stay in a hospital hepatogastroenterology unit].

The long term results of psychologically oriented treatment for alcoholism were evaluated in 147 patients hospitalized in a liver unit and followed for 1-5 years. Twenty-three percent of the patients were hospitalized for treatment of alcoholism, while 61 percent were hospitalized for alcohol-related disease. The main patient characteristics were: males: 71 percent; age: 48 +/- 10 years (mean +/- SD); alcoholic cirrhosis: 48 percent; initial request for help in abstinence: 9 percent; and unemployment: 35 percent. During the hospitalization (16 +/- 10 days), each patient had 1 to 4 psychotherapeutic interviews. Seventy-four percent of patients responded to follow-up after discharge and contact was maintained in 23 percent of patients 2 years thereafter. The only two independent prognostic variables for long-term follow up were the need for medical supervision (P less than 0.001) and employment (P less than 0.005) (Cox model). Only 10 percent of the patients attended a post-hospitalisation psychotherapeutic program. Among the 108 patients who were followed, 35 percent were totally abstinent immediately after discharge and 17 percent did not relapse during the 2 following years. Relapse was unpredictable according to any of the initial variables. Half of the patients who were abstinent immediately after discharge remained totally so at long-term follow-up. Total abstinence was obtained for 39 percent of patients during a mean period of 27 +/- 34 months. Medical, social, or psychological improvement was observed more often in abstainers (61 percent) than in non abstainers (11 percent, P less than 0.001). We conclude that: a) long-term follow-up and abstinence were infrequently obtained in unselected alcoholic patients hospitalized in a liver unit; b) no initial criteria could predict the alcoholic relapse or select patients for alcoholism treatment; c) long-term results seemed more favorable when the patients where totally abstinent immediately after discharge.

Adult↗
PubMed1991

[Nodular regenerative hyperplasia and primary biliary cirrhosis].

We report two cases of nodular regenerative hyperplasia of the liver associated with primary biliary cirrhosis. Cholestasis and presence of antimitochondrial antibodies were noted in both patients. In one patient, the diagnosis of nodular regenerative hyperplasia was supported by the demonstration of disseminated small hepatic nodules without perinodular fibrosis. Twelve years later, the histopathological picture was one of primary biliary cirrhosis. The other patient presented an histological picture of regenerative hyperplasia of the liver and primary biliary cirrhosis. The association of regenerative hyperplasia of the liver and primary biliary cirrhosis is discussed.

Biopsy↗
PubMed1991

Anatomy of the hypothalamic-pituitary axis.

The recent discovery of several hypothalamic factors involved in the regulation of anterior pituitary function and the development of sensitive immunocytochemical techniques have greatly contributed to a better identification of the hypothalamic nuclei and individual neurons involved in the production of the hypophysiotropic factors. Each peptidergic factor is produced by a group of parvocellular neurons located in different hypothalamic areas and projecting to the external zone of the median eminence. These results obtained in the last few years fully confirm previous data obtained on the basis of lesion experiments which had established that the hypophysiotropic areas were localized in the hypothalamus. Studies performed at the electron-microscopic level indicate that hypophysiotropic peptidergic factors are contained in dense core vesicles within the cytoplasm of neuronal cell bodies. From there, the dense core vesicles migrate along the axons to reach the external zone of the median eminence where they are stored in endings. On appropriate stimulation, the hormones are released into the capillaries of the pituitary portal plexus. These parvocellular neurosecretory systems then appear to be very similar to the classic magnocellular neurosecretory systems involved in the secretion of vasopressin and oxytocin (fig. 1).

Animals↗
PubMed1991

Accelerated coronary atherosclerosis after cardiac transplantation: major threat to long-term survival.

Accelerated coronary atherosclerosis (ACA) has been documented at autopsy and was noted at coronary angiography in seven patients, 11 to 48 months after cardiac transplantation. To delineate the importance of this problem, the risk factors and the therapeutic approaches in 7 patients who had ACA after heart transplantation were compared with those in 28 patients free of ACA at annual coronary angiography. Ischemic cardiomyopathy was the preoperative diagnosis in all but one patient in the ACA group. The age of the transplant recipients, total myocardial ischemic times and arterial blood pressures at follow-up were similar in both groups. Donor age averaged 31 +/- 3 years in the ACA group and 22 +/- 1 years in patients free of ACA. Preoperative cholesterol, triglyceride and high-density lipoprotein levels were lower in ACA-free patients and the low-density lipoprotein level was higher. At the last follow-up visit, serum lipid levels were similar in both groups. The incidence of acute rejection and of infection was slightly, but not significantly, higher in patients with ACA. The actuarial survival of ACA patients 4 years after transplantation was 30% +/- 20% compared with 100% for patients free of ACA (p less than 0.01). Actuarial rates of freedom from ACA and from death due to ACA were 73% +/- 11% and 81% +/- 11% respectively. Stepwise discriminant analysis showed that older donors and higher pretransplant triglyceride levels were independently related to the development of ACA after cardiac transplantation. In conclusion ACA remains an important cause of late death after heart transplantation. Although therapeutic measures are limited, prevention should focus on strict control of serum lipid levels after transplantation.

Adult↗
PubMed1990

Ontogeny of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) in human adrenal gland performed by immunocytochemistry.

Human foetal adrenal plays a major role in the synthesis and secretion of steroids which are essential to several physiological events during foetal development. Since 3 beta-hydroxysteroid dehydrogenase 5-ene-4-ene isomerase (3 beta-HSD) is involved in the biosynthesis of all classes of hormonal steroids, namely progesterone, glucocorticoids, mineralocorticoids, androgens and estrogens, knowledge of the ontogeny of 3 beta-HSD should lead to a better understanding of steroidogenesis in the foetal adrenal. Polyclonal antibodies raised against purified human placental 3 beta-HSD were used to localize the enzyme in 22-week, 28-week, and term foetal adrenals as well as in the adrenals of 2-month-, 8-month- and 2-year-old infants. 3 beta-HSD has been identified in the outer cortex, neocortex and zona glomerulosa zone of foetal adrenal, respectively. In 2-month- and 8-month-old infant adrenals, the enzyme was localized in the zona glomerulosa and zone fasciculata while in 2-year-old infants, the immunoreaction was observed also in the zona reticularis, the medulla being devoid of any reaction.

Adrenal Glands↗
PubMed1990

Effects of human chorionic gonadotropin (hCG) and prolactin (PRL) on 3 beta-hydroxy-5-ene-steroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) expression and activity in the rat ovary.

Using a recently cloned rat ovary 3 beta-HSD cDNA and antibodies raised against purified human placental 3 beta-HSD, we have studied the effects of treatment with human chorionic gonadotropin (hCG) and hyperprolactinemia achieved by pituitary implants, alone or in combination, on the expression and activity of ovarian 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) in intact adult rats. 32P- and 35S-labeled cDNA probes were used to evaluate the effects of treatments on 3 beta-HSD mRNA levels by dot blot and in situ hybridization, respectively, while enzymatic activity was measured by the conversion of [14C]dehydroepiandrosterone into [14C]androstenedione. The present data show that hCG exerts a marked trophic effect on rat corpora lutea with an increase in total ovarian 3 beta-HSD mRNA levels, 3 beta-HSD protein content as well as enzymatic activity, resulting in an increase in serum progesterone levels. Prolactin-secreting pituitary implants alone, on the other hand, while exerting small effects on 3 beta-HSD expression and activity, led to a marked potentiation of the stimulatory effect of hCG on all parameters. The present data show that hCG and PRL act synergistically to stimulate ovarian progesterone secretion via an increase in 3 beta-HSD mRNA levels, protein content and enzymatic activity.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

Localization and characterization of neuropeptide Y in the brain of Microcebus murinus (Primate, Lemurian).

The distribution of neuropeptide Y (NPY) in the brain of the lemur Microcebus murinus was determined by immunocytochemistry with the aid of a highly specific antiserum against synthetic porcine NPY. When compared with previous immunohistochemical data obtained in primates and other mammalian species, the localization of NPY-immunoreactive (IR) structures in the Microcebus murinus brain revealed particular features. (1) Numerous NPY-IR perikarya and a dense network of IR nerve terminals were found in the supraoptic and suprachiasmatic nuclei, respectively. The occurrence of NPY-IR perikarya in the supraoptic nucleus, also reported in the squirrel monkey, seems to be specific to primates. In the squirrel monkey, the suprachiasmatic nucleus exhibits only a moderate innervation, whereas in humans it appears totally devoid of NPY-IR fibers. (2) IR perikarya and axon processes were observed in many upper brainstem areas, in particular in the interpeduncular, raphe pontine, dorsal tegmental, parabrachial, and dorsal raphe nuclei, in the locus coeruleus, the nucleus of the solitary tract, and the reticular formation; in this latter area, the occurrence of two categories of NPY-IR neurons was demonstrated on the basis of their morphology and localization, suggesting that they may play distinct roles. (3) NPY-IR nerve processes could be traced over a long distance. (4) For the first time, numerous NPY-IR terminals were observed close to the lumen of the various cerebral ventricles. The immunoreactive NPY-like peptide was characterized by combining high performance liquid chromatography (HPLC) analysis and radioimmunoassay quantification. The dilution curves obtained with synthetic porcine NPY and serial dilutions of occipital cortex, paraventricular and supraoptic hypothalamus, posterior hypothalamus, medulla oblongata, or preoptic area extracts were parallel. The highest amounts of NPY were measured in the hypothalamus and telencephalon. HPLC analysis resolved a single peak of NPY-like immunoreactivity that exhibited the same retention time as synthetic porcine NPY. The distribution of NPY in the lemurian brain is discussed with respect to phylogeny and putative functions.

Animals↗
PubMed1990

[Diagnosis and monitoring of acute viral hepatitis A, B and C].

Acute viral hepatitis A, B and D share a common clinical complex including 4 phases: incubation, pre-icteric phase, icteric phase and convalescence. The diagnosis, suggested by clinical symptoms and by biochemical abnormalities that are often characteristic, must be confirmed by viral serology. Hepatitis A never becomes chronic. With hepatitis B or B and D, evolution to chronicity is possible, and the patients should be investigated for the return to normal values of transaminases, the disappearance of the HBs antigen and the appearance of anti-HBs antibodies. There is no specific treatment of acute viral hepatitis, but in case of hepatitis B prophylactic measures must be taken in the husband, the wife or the partner.

Acute Disease↗
PubMed1990

Regulation of proopiomelanocortin messenger ribonucleic acid content by sex steroids in the arcuate nucleus of the female rat brain.

It has been recently demonstrated that sex steroids can negatively regulate beta-endorphin content as well as proopiomelanocortin (POMC) mRNA levels in the rat basal hypothalamus. In order to verify whether or not all the POMC neurons are equally affected by sex steroids, we arbitrarily divided the arcuate nucleus rostro-caudally into four equal portions and used an in situ hybridization technique to evaluate POMC gene expression in these different regions of the arcuate nucleus in the female rat. It was shown that ovariectomy induced an increase in mRNA levels in the most rostral region of the arcuate nucleus, an effect which was reversed by the concurrent administration of estradiol and dihydrotestosterone. On the other hand, estrogen administration to ovariectomized animals produced a marked depression of mRNA levels in all the regions of the arcuate nucleus with the exception of the most caudal one. These results suggest that sex steroids exert their action in subpopulations of POMC neurons.

Animals↗
PubMed1990

Synthetic progestins stimulate prostatic binding protein messenger RNAs in the rat ventral prostate.

In order to assess the intrinsic androgenic activity of the synthetic progestins currently used as antiandrogens for the treatment of prostate cancer and other androgen-sensitive diseases, cyproterone acetate (CPA), medroxyprogesterone acetate (MPA) and megestrol acetate (MEG) were administered for 4 days to adult rats castrated 4 days previously. The effects of these compounds were measured on highly specific and sensitive markers of androgen action in the rat ventral prostate, namely the levels of messenger RNAs encoding the C1 (PBP-C1) and C3 (PBP-C3) components of rat prostatic binding protein (PBP). Steady-state mRNA levels were measured by dot-blot hybridization as well as by in situ hybridization. Treatment with CPA or MEG, at the twice daily dose of 10 mg, caused respective 2- and 4.5-fold increases in the steady-state levels of mRNA encoding PBP-C1. MPA, at the dose of 0.45 mg, twice daily, was approximately 40 times as potent as MEG, leading to an 8-fold increase in PBP-C1 mRNA levels. While the pure nonsteroidal antiandrogen flutamide (10 mg, twice daily) did not cause accumulation of PBP mRNAs when administered to castrated rats, it completely reversed the stimulatory effects of the synthetic progestins CPA, MPA and MEG. The results obtained by in situ hybridization were similar to those obtained by dot-blot analysis. Moreover, the synthetic progestins caused similar androgenic effects on PBP-C3 mRNA levels. The present data indicate that all three synthetic progestins currently used for the treatment of prostate cancer possess significant intrinsic androgenic activity as evidenced by their stimulatory effects on the accumulation of mRNAs sensitive to androgen action. Consequently, as indicated by this sensitive and androgen-specific in vivo rat model, such compounds are not recommended for the treatment of conditions requiring an optimal blockade of androgens, especially prostate cancer.

Androgen-Binding Protein↗
PubMed1990

Expression of the 2S albumin from Bertholletia excelsa in Brassica napus.

The methionine rich 2S albumin seed storage protein of Bertholletia excelsa has been expressed in seeds of Brassica napus (rapeseed). A chimeric gene driven by the soybean lectin 5' flanking regions was used to produce a fusion protein consisting of the soybean lectin signal peptide and the propeptide of the Brazil nut 2S albumin. Several transgenic plants were studied at the RNA and protein levels; in each case the chimeric gene was expressed and the protein detected at levels ranging from 0.02% to 0.06% of total protein. Transcriptional studies in a particular transgenic plant show that expression of the gene is tissue specific and developmentally regulated during seed maturation. The endogenous napin genes and the introduced gene are regulated differently, with expression of the chimeric gene paralleling that seen when the soybean lectin gene is expressed in other plant species. Western analysis using antibodies to Brazil nut 2S albumins resulted in the detection of a protein whose size is consistent with correct processing of the precursor.

Amino Acid Sequence↗
PubMed1990

The origin of the intrinsic glycoproteins of the rabbit vitreous body: an immunohistochemical and autoradiographic study.

A cartilage matrix glycoprotein (CMGP), previously identified in human and bovine vitreous, now has been found in the vitreous body of rabbits aged 1-22 months by immunohistochemical techniques. Epithelial cells of the inner layer of the ciliary epithelium contain material that has immunologic cross-reactivity with a specific antibody to CMGP. These cells also secrete glycoproteins, as determined by autoradiography after intravitreal injection of [3H]fucose. Approximately 14 bands, representing intrinsic glycoproteins containing fucose residues, can be identified in fluorograms of SDS-polyacrylamide gels of vitreous bodies from 6- and 22-month-old rabbits. Fluorograms of gels of samples of vitreous and ciliary bodies from several time points after intravitreal injection of [3H]fucose reveal at least seven comigrating protein bands and also demonstrate turnover of the labeled ciliary body glycoproteins. These results suggest that the inner layer of the ciliary epithelium is the source of the glycoproteins of the vitreous body and that these glycoproteins undergo turnover, probably throughout the entire life of the animals.

Animals↗
PubMed1990

Nodular regenerative hyperplasia of the liver, peliosis hepatis, and perisinusoidal fibrosis. Association with angioimmunoblastic lymphadenopathy and severe hypoxemia.

Three different liver lesions were found in a 20-year-old woman with angioimmunoblastic lymphadenopathy. The lesions included nodular regenerative hyperplasia of the liver, perisinusoidal fibrosis, and peliosis hepatis. It is suggested that the association of angioimmunoblastic lymphadenopathy with this broad spectrum of liver lesions was not fortuitous.

Adult↗
PubMed1990

Ontogeny of proopiomelanocortin (POMC) gene expression in the intermediate lobe of the rat pituitary gland.

The ontogeny of proopiomelanocortin (POMC) gene expression in the intermediate lobe of the pituitary was studied in rats of both sexes using quantitative in situ hybridization performed on fixed pituitary sections. Electron microscopic studies revealed in the adult animal the hybridization signal was found in all the secretory cells of the intermediate lobe and only in the POMC cells in the anterior lobe, thus indicating the specificity of the technique used. Hybridization signal was first detected on day 15 of gestation and progressively increased during foetal life. After birth, POMC and mRNA levels markedly increased so that, in one-day old animals, they were 4.5-fold higher than at the end of gestation. Thereafter, mRNA concentrations steadily increased to reach a plateau at 60 days of age in both sexes. No sexual dimorphism was observed at any ages. The results indicate that the development of intermediate lobe cells occurs mostly after birth. They are consistent with previous results indicating a 200-fold increase in the levels of POMC-derived peptides from birth to adulthood.

Animals↗