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E Dupont

Publications and source records attributed to E Dupont.

At least 163 records · Page 9Linked to original sources
PubMed1990

Changes in the expression of connexin 43, a cardiac gap junctional protein, during mouse heart development.

A cDNA probe coding for rat connexin 43 (Beyer et al., 1987), a gap junctional protein, was used to detect specific mRNA and estimate its relative abundance in mouse heart at different developmental stages: 11, 14 and 19 days post-coïtum (dpc); 1, 2 and 3 weeks post-partum (wpp), and at the adult stage. On Northern blots of total cellular RNA, a single 3.0 kb message was detected at all stages of development, and the differential intensities of labeling indicated developmental changes in mRNA abundance. mRNA levels were further investigated by dot-blotting. Densitometric analyses of dot-blot autoradiograms showed a five-fold increase of the mRNA level between 11 dpc and 1 wpp, then a gradual decrease until the adult stage where it reached a value close to that detected at 11 dpc. By comparison, myosin heavy chains and glycerldehyde-3-phosphate dehydrogenase mRNAs were found to peak at 3 wpp and 14 dpc, respectively. The presence and the relative abundance of connexin 43 were investigated at the same developmental stages as previously by immunoblotting of whole-ventricle fractions using antipeptide antibodies specific for this junctional protein. Quantitative data obtained from densitometric analyses of immunoblots showed that from 14 dpc to 1 wpp intensity of labeling of connexin 43 was roughly multiplied by a factor of 10. It peaked at 3 wpp before dropping to about 20% at the adult stage. The data obtained with both the cDNA probe and the antibodies were significant as shown by variance analyses. They suggest that expression of cardiac connexin 43 is developmentally-regulated: at the early stages of heart development the expression levels of the protein would seem to be mainly regulated by mRNA abundance; beyond 2 weeks after birth, the levels of connexin 43 would seem rather to depend upon its stability and/or the efficiency of the translation.

Amino Acid Sequence↗
PubMed1990

Light microscopic immunocytochemical localization of 3 beta-hydroxy-5-ene-steroid dehydrogenase/delta 5-delta 4-isomerase in the gonads and adrenal glands of the guinea pig.

The enzyme complex 3 beta-hydroxy-5-ene-steroid dehydrogenase/delta 5-delta 4-isomerase (3 beta HSD) is involved in the biosynthesis of all classes of active steroids, namely glucocorticoids, mineralocorticoids, progesterone, and sex hormone steroids. To obtain precise information about the cellular and subcellular localization of 3 beta HSD in the gonads and adrenals of the guinea pig, we have proceeded to immunocytochemical localization of the enzyme using antibodies developed against purified human placental 3 beta HSD. In the testis, specific immunostaining was restricted to the cytoplasm of the interstitial cells. In the ovary, on the other hand, immunostaining was found in the cytoplasm of the cells of the corpus luteum and theca interna. The granulosa cells of the follicles were not immunolabeled, with the exception of one layer of cells in contact with the zona pellucida. This restricted labeling was observed in growing and mature follicles, but not in primordial and small primary follicles. In the adrenals, the three zones of the cortex were labeled, whereas no staining could be detected in the medulla. Contrary to findings in the testis and ovary, staining was found in both the cytoplasm and nuclei of adrenocortical cells. The present data suggest a functional interaction between the ovocyte and the specialized layer of 3 beta HSD-containing granulosa cells which might play a role in ovocyte maturation.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

Localization of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase in rat gonads and adrenal glands by immunocytochemistry and in situ hybridization.

The enzyme complex delta 5-3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta HSD) is involved in the biosynthesis of all classes of steroids, namely glucocorticoids, mineralocorticoids, progesterone, and sex steroids. To obtain information on the precise localization of 3 beta HSD in rat gonads and adrenal glands, two complementary cytochemical techniques were used; immunocytochemical localization was achieved with antibodies developed against purified human placental 3 beta HSD, while 3 beta HSD mRNA localization was achieved by in situ hybridization performed with a recently cloned rat 3 beta HSD cDNA. In the testis, specific immunostaining was restricted to the cytoplasm of the interstitial cells, while by in situ hybridization, specific silver grains were also seen over the interstitial cells. In the ovary, immunostaining was found in the cytoplasm of cells of the corpus luteum and theca interna, while the granulosa cells of the follicles showed no positive reaction. By in situ hybridization, a specific hybridization signal was observed over granulosa cells of the corpus luteum, which are mainly responsible for progesterone secretion, and to a lesser extent over theca interna cells, known for their role in secreting C19 androgens. In the adrenals, the three zones of the cortex were equally immunolabeled, whereas no staining could be detected in the medulla. Similarly, by in situ hybridization, silver grains were located over the zona glomerulosa, fasciculata, and reticularis, while no specific autoradiographic reaction could be observed on the chromaffin cells of the medulla. The present study provides new information about the precise cellular localization of 3 beta HSD in the adrenal glands and gonads in the rat, thus providing useful information about the site of action of 3 beta HSD, especially in the gonads. Moreover, the approaches used for localization studies, especially quantitative in situ hybridization, should provide a useful tool for assessing the role of hormones on 3 beta HSD expression in the different compartments of the gonads and adrenal glands.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

Changes in 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase messenger ribonucleic acid, activity and protein levels during the estrous cycle in the bovine ovary.

A 1169 base pair fragment of bovine 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) cDNA was used to quantitate 3 beta-HSD messenger RNA (mRNA) levels in the bovine ovary during the estrous cycle. The content of 3 beta-HSD protein was measured by immunoblot analysis using an antiserum developed in rabbits against human 3 beta-HSD, whereas 3 beta-HSD activity was measured using [3H]pregnenolone, [3H] dehydroepiandrosterone, and [3H]androst-5-ene-3 beta,17 beta-diol as substrates. There was a parallel increase in 3 beta-HSD mRNA, protein content, and enzymatic activity levels from days 1-3 after estrus to maximal values at 50-100% above control on days 8-11 after estrus. Thereafter, all values decreased progressively until days 16-17 before a dramatic fall to 5% or less than maximal values on days 18-20 after estrus. Almost superimposable results of enzymatic activity were obtained with the three substrates, thus suggesting a unique 3 beta-HSD or parallel changes in the activity of multiple 3 beta-HSDs. The above-described changes observed during the luteal phase are almost exclusively due to variations in corpora lutea. In fact, 3 beta-HSD activity in ovarian follicles was approximately 10,000 lower than that measured in corpora lutea. The close correlation observed over a wide range of 3 beta-HSD mRNA, protein content, and activity levels suggests that changes of ovarian 3 beta-HSD activity are controlled at the level of 3 beta-HSD gene expression and/or 3 beta-HSD mRNA stability.

Animals↗
PubMed1990

Regulation of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase expression and activity in the hypophysectomized rat ovary: interactions between the stimulatory effect of human chorionic gonadotropin and the luteolytic effect of prolactin.

The enzyme 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) catalyzes an obligatory step in the conversion of pregnenolone and other 5-ene-3 beta-hydroxysteroids into progesterone as well as precursors of all androgens and estrogens in the ovary. Since 3 beta-HSD is likely to be an important target for regulation by pituitary hormones, we have studied the effect of chronic treatment with LH (hCG), FSH, and PRL on ovarian 3 beta-HSD expression and activity in hypophysectomized adult female rats. Human CG (hCG) [10 IU, twice a day (bid)], ovine FSH (0.5 microgram, bid), and ovine PRL (1 mg, bid) were administered, singly or in combination, for a period of 10 days starting 15 days after hypophysectomy. In hypophysectomized rats, PRL exerted a potent inhibitory effect on all the parameters studied. In fact, PRL caused a 81% decrease in ovarian 3 beta-HSD mRNA content accompanied by a similar decrease in 3 beta-HSD activity and protein levels. In addition, ovarian weight decreased by 40% whereas serum progesterone fell dramatically from 1.92 nmol/liter to undetectable levels after treatment with PRL. Whereas hCG alone had only slight stimulatory effects on 3 beta-HSD mRNA, protein content and activity levels, treatment with the gonadotropin partially or completely reversed the potent inhibitory effects of oPRL on all the parameters measured. FSH, on the other hand, had no significant effect on 3 beta-HSD expression and activity. In situ hybridization experiments using the 35S-labeled rat ovary 3 beta-HSD cDNA probe show that the inhibitory effect of PRL is exerted primarily on luteal cell 3 beta-HSD expression and activity. On the other hand, it can be seen that hCG stimulates 3 beta-HSD mRNA accumulation in interstitial cells. The present data show that hCG and PRL exert potent and opposite cell-specific effects on ovarian 3 beta-HSD expression, activity, and content in the rat ovary. Moreover, the present study could suggest that female infertility associated with hyperprolactinemia in women could well be related, at least in part, to the potent inhibitory effect of PRL on ovarian 3 beta-HSD expression and activity.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

CQA 206-291: a novel dopamine agonist in the treatment of Parkinson's disease.

The antiparkinsonian efficacy and tolerability of CQA 206-291, a novel ergoline derivative with potent dopamine agonist properties, were studied during 2 months of treatment in 72 parkinsonian patients. In 36 de novo patients (patients who have not previously been treated with levodopa or dopamine agonists), CQA 206-291 was studied in an open design, while in 36 levodopa-treated patients, CQA 206-291 was studied in a randomized, double-blind, parallel-group, placebo-controlled design. CQA 206-291 induced in both groups a significant antiparkinsonian effect with an effective dose range of 5-30 mg/day. The spectrum of adverse events was similar to what is commonly observed with dopamine agonists. Further studies are required to assess the putative therapeutic advantages of CQA 206-291 when compared to other antiparkinsonian drugs.

Aged↗
PubMed1990

[Recurrence of Wegener's granulomatosis in a cadaver kidney graft].

Early recurrence of Wegener's granulomatosis on a kidney graft is described in a 35-year-old patient. The differential diagnosis of renal microvasculitides is discussed as well as the problem related to characterization and specificity of antineutrophil cytoplasmic antibodies. Possible factors influencing the risk of recurrence of Wegener's granulomatosis on the graft are detailed after reviewing five cases from the literature.

Adult↗
PubMed1989

Cross-linking of cardiac gap junction connexons by thiol/disulfide exchanges.

SDS-polyacrylamide gel electrophoresis and immunoblotting were used to investigate inter- and intramolecular disulfide bonds to connexin 43 (the cardiac gap junctional protein) in isolated rat heart gap junctions and in whole heart fractions. In gap junctions isolated in the absence of alkylating agent, connexin 43 molecules are cross-linked by disulfide bonds. The use of iodoacetamide (100 mM) for the first steps of isolation procedure prevents the formation of these artifactual linkages. Investigation of connexin 43 in whole heart fractions by means of antibodies confirms the results obtained with isolated gap junctions; that is, connexin 43 molecules are not interconnected with disulfide bridges. In whole heart fractions treated with alkylating agents, a 38 kD protein, immunologically related to connexin 43, and containing intramolecular disulfide bonds is detected. It is hypothesized that this protein might be a folded form of connexin 43, a precursory form of the molecules embedded in the gap junctions.

Animals↗
PubMed1989

Release of tumor necrosis factor, interleukin-2, and gamma-interferon in serum after injection of OKT3 monoclonal antibody in kidney transplant recipients.

High levels of tumor necrosis factor-alpha, interleukin-2, and gamma-interferon appeared in the circulation of kidney transplant recipients after the first injection of the monoclonal antibody OKT3. This initial injection was systematically followed by fever. The three cytokines were released in all patients (n = 9), with peak serum levels of tumor necrosis factor occurring 1 hr after OKT3 injection and those of interleukin-2 and gamma-interferon after 2 hr. Cytokines were not released after the second and third OKT3 injections, when CD3+ cells had disappeared from blood. These findings suggest that circulating cytokines are released by T cells after activation by OKT3. These cytokines are probably involved in the systematic reactions observed after injection of OKT3.

Antibodies, Monoclonal↗
PubMed1989

HLA-B SNA antigen: a BW6 associated B locus antigen belonging to the B5 CREG.

A new B locus antigen has been found in members of two unrelated families and in a patient originating from Morocco belonging to the Berber population. A complete analysis has been performed with antisera from the 9th and 10th IHWS defining the B5 CREG antigens. Serology, absorption experiments and family studies indicate that SNA antigen is a Bw6 associated subtype of B5 antigen closely related to but clearly distinct from each of the B5 CREG antigens. One-dimensional isoelectric focusing study (1D-IEF) confirms that the SNA antigen precipitates as a B locus gene product and has an isoelectric point identical to that of Bw52 and one of the charge variants of B51.

Cross Reactions↗
PubMed1989

Selegiline and levodopa in early or moderately advanced Parkinson's disease: a double-blind controlled short- and long-term study.

Selegiline 10 mg per day was compared to placebo as an adjunct to levodopa treatment in this double-blind study of early or moderately advanced Parkinson's disease. Thirty-eight patients completed an initial cross-over trial comprising two treatment periods, each of eight weeks, with a four weeks' wash-out period between them. Thirty of the patients continued in a long-term, double-blind parallel trial with a mean duration of 16 months (range 6-30 months). Selegiline treatment allowed a significant reduction of the necessary daily levodopa dose in both parts of the study and of the daily dosing frequency in the long-term investigation. In spite of this reduction of levodopa dose, an improvement was noted in tremor during the short-term selegiline periods. The side-effects were slight and related to dopamine effects and disappeared after reduction of levodopa-dose. The results support the use of selegiline as an early adjunctive treatment in Parkinson's disease.

Aged↗
PubMed1989

Regulation of pro-gonadotropin-releasing hormone gene expression by sex steroids in the brain of male and female rats.

The fine modulation of gonadotropin gene expression and secretion is well recognized to be regulated by sex steroids through their direct action both at the anterior pituitary level and on the pulsatile pattern of GnRH secretion at the hypothalamic level. Since the influence of sex steroids on hypothalamic GnRH mRNA levels remains to be elucidated, quantitative in situ hybridization was used to study the effect of sex steroids on cellular levels of pro-GnRH mRNA in adult rats of both sexes. The effects of 14-day gonadectomy as well as administration of 17 beta-estradiol (E2, 0.25 micrograms) or dihydrotestosterone (DHT, 100 micrograms) twice a day during 14 days to gonadectomized animals were evaluated. In addition, the effect of progesterone (P, 2 mg, twice daily) alone or in the presence of E2 was also studied in ovariectomized animals. Hybridization was performed using a 35S-labeled cDNA probe encoding rat pro-GnRH and the corresponding mRNA levels were assessed by counting the number of silver grains overlying labeled neurons. In male rats, castration induced a highly significant 65% increase (compared to intact rats) in the mean number of grains per neuron. Administration of E2 or DHT to castrated animals completely prevented the post castration rise in pro-GnRH mRNA levels. In female animals, the effect of ovariectomy was less striking than in the male, a 25% increase (P less than 0.001) being observed. Treatment with E2 or DHT also completely prevented the increase in pro-GnRH mRNA levels induced by ovariectomy. Moreover, treatment with P in ovariectomized animals markedly potentiated the inhibitory effect of E2 on pro-GnRH mRNA levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

High interleukin-6 serum levels and increased production by leucocytes in alcoholic liver cirrhosis. Correlation with IgA serum levels and lymphokines production.

Hypergammaglobulinaemia and enhanced serum IgA levels are common in alcoholic liver cirrhosis. Interleukin-6 (IL-6), which is identical to B cell differentiation factor BSF2 and is implicated in various autoimmune diseases, has been studied in patients with alcoholic liver cirrhosis. Increased serum levels and spontaneous or induced production of IL-6 by peripheral blood monoclonal cells have been found. IL-6 production correlates closely with IgA serum levels and negatively with impaired interleukin-2 and interferon gamma production. This abnormality could be related to overproduction of immunoglobulins and immune disturbances observed in this disease.

Female↗