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E Dupont

Publications and source records attributed to E Dupont.

At least 145 records · Page 8Linked to original sources
PubMed1991

Characterization of rat 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase cDNAs and differential tissue-specific expression of the corresponding mRNAs in steroidogenic and peripheral tissues.

The conversion of 3 beta-hydroxy-5-ene steroids by the enzyme complex 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) is an essential step in the biosynthesis of all classes of hormonal steroids. We report the characterization of two types of cDNA clones encoding rat 3 beta-HSD isolated from a rat ovary lambda gt11 cDNA library with a human 3 beta-HSD cDNA probe. Both type I and type II cDNAs encode proteins of 372 amino acids having 94% homology. Transient expression of the type I and the type II 3 beta-HSD cDNAs in HeLa human cervical carcinoma cells reveals that both proteins possess 3 beta-hydroxysteroid dehydrogenase as well as delta 5-delta 4 isomerase activities for both delta 5-pregnene and delta 5-androstene precursors, although the type I 3 beta-HSD protein is more active than the type II. RNA blot analysis using type I 3 beta-HSD cDNA identifies major mRNA transcripts of 1.7 kilobase in rat ovary, testis, and adrenal poly(A)+ RNA. RNase protection assay using type I- and type II-specific cRNA probes revealed the existence of the two corresponding mRNAs in male and female rat adrenals and gonads as well as in female adipose tissue while only type I mRNA is present in male and female kidney. Moreover, in situ hybridization performed using type-specific labeled 24-mer oligonucleotides confirms that type I is the major mRNA species in the ovary and further indicates that both mRNA species have a similar cellular distribution in the ovarian tissue with the highest level of expression found in corpora lutea. Immunoblot analysis using polyclonal antibodies raised against purified human placental 3 beta-HSD identified a single 42-kDa band in rat ovary, testis, and adrenal, which agrees with the calculated molecular masses of 41,911 and 42,150 daltons for the type I and II proteins, respectively. Determination of 3 beta-HSD enzymatic activity using [14C]pregnenolone and [14C]dehydroepiandrosterone as substrates shows that 3 beta-HSD activity is present not only in the gonads and adrenals of animals of both sexes, but also in many peripheral tissues including adipose tissue, mammary gland, kidney, liver, prostate, seminal vesicle, uterus, skin, brain, heart, thymus, pancreas, lung, and spleen. The present data indicate the existence of two mRNAs encoding rat 3 beta-HSD and their differential tissular distribution in both steroidogenic and peripheral tissues.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed1991

The hemodynamic effects of triglycyl-lysine-vasopressin (Glypressin) in patients with parkinsonism and orthostatic hypotension.

The hemodynamic effects of triglycyl-lysine-vasopressin (TGLVP) were investigated in a single-blind study in seven patients with chronic orthostatic hypotension and parkinsonism. Blood pressure, heart rate, and stroke volume were measured in the supine position before and after bolus injection of either placebo or TGLVP (5.0, 7.5, or 10.0 micrograms/kg of body weight). After 40 min in the supine position, the patients were head-up tilted to 45 degrees for 20 min. All patients underwent four tilt studies with different medication. The TGLVP increased supine blood pressure by approximately 25% and total peripheral resistance by approximately 46%, and reduced heart rate by approximately 13%. No changes in supine stroke volume or cardiac output were seen. The TGLVP slightly reduced the relative fall in blood pressure and increased heart rate during the tilt. After TGLVP, blood pressure levels during tilt were similar to supine levels prior to medication. The TGLVP did not change the effects of tilt on stroke volume or cardiac output. Only few and mild side effects were experienced and no cardiotoxic effects were observed. In conclusion, TGLVP showed marked blood pressure effects of very small doses in this category of patients. The clinical effects of TGLVP and other vasopressor-specific analogs of vasopressin should be tested in these patients.

Aged↗
PubMed1991

Interleukin-6 administration has no acute hemodynamic or hematologic effect in the dog.

To investigate the possible hemodynamic effects of interleukin-6 (IL-6), a single dose of 15 mcg/kg of recombinant IL-6 isolated from Escherichia coli was injected intravenously in six pentobarbital-anesthetized dogs. After 30 min, saline infusion was performed to maintain the pulmonary artery balloon-occluded pressure at baseline level. The animals were observed for up to 5 hours. No other hemodynamic alteration was observed than a gradual decline in cardiac output attributed to anesthesia. Hematologic variables, blood glucose, and total serum proteins were also constant. IL-6 levels were markedly elevated in the blood, but no tumor necrosis factor activity was detected. Thus a primary role for IL-6 in the early cardiovascular alterations associated with septic shock seems unlikely.

Animals↗
PubMed1991

Glutathione peroxidase in early and advanced Parkinson's disease.

A defective antioxidant scavenging system plays a major role in one of the theories of the pathogenesis of Parkinson's disease. The aim of this study was to investigate whether there is a general difference in antioxidant activity between early and advanced cases of Parkinson's disease. Twenty five recently diagnosed patients, without any clinical fluctuations (group A), and 25 patients in a late phase of the disease with severe fluctuations in response to levodopa therapy (group B) were included in the study. Erythrocyte glutathione peroxidase was determined as a measure of antioxidant activity and significantly lower values were found in group B than in group A. Regression analyses in groups A and B showed significant correlation between glutathione peroxidase and duration of disease, but not between glutathione peroxidase and age of patients.

Aged↗
PubMed1991

Localization of 17 beta-hydroxysteroid dehydrogenase throughout gestation in human placenta.

17 beta-Hydroxysteroid dehydrogenase (17 beta-HSD) is the enzyme responsible for the formation of all sex steroids in gonadal as well as extragonadal tissues. To obtain more information about the age-specific expression of 17 beta-HSD in the human placenta, we have localized this enzyme by immunocytochemistry at the light microscopic level at different periods of gestation. In the 7- and 9-week-old placenta, immunostaining was detected exclusively in the cytoplasm of the syncytiotrophoblast. Between the tenth and thirteenth weeks of gestation, immunolabeling was also observed in the cytoplasm of the cytotrophoblastic cells, suggesting that these cells could be transiently involved in the biosynthesis of sex steroids. Interestingly, between the fourteenth and twenty-fifth weeks of gestation, 17 beta-HSD was observed in both the cytoplasm and nucleus of the syncytiotrophoblast. The reaction product was much more intense in nuclei than in cytoplasm. During the last trimester of gestation, strong immunocytochemical staining was observed in all the nuclei of the syncytiotrophoblast, the cytoplasm being unstained. The meaning of this nuclear staining for 17 beta-HSD is still unclear and remains to be extensively investigated.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

Ontogenesis of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase in the rat adrenal as revealed by immunocytochemistry and in situ hybridization.

The enzyme 3 beta-hydroxy-5-ene-steroid dehydrogenase/5-ene-4-ene isomerase (3 beta-HSD) catalyzes an essential step in the biosynthesis of all classes of active steroids, namely glucocorticoids, mineralocorticoids, progesterone, and sex steroids. To obtain further information on the expression and localization of 3 beta-HSD during development in the rat adrenal, two complementary cytochemical techniques were used: immunocytochemical localization with antibodies against purified human placental 3 beta-HSD, and 3 beta-HSD messenger RNA localization achieved by in situ hybridization with a rat 3 beta-HSD complementary DNA probe. During foetal development, the first detection of 3 beta-HSD messenger RNA was achieved on day 16 by in situ hybridization, the silver grains being located on the cortical cells. Between days 17 and 20, on the other hand, immunostaining became positive in the cytoplasm of the same cortical cells, the capsule being negative by both immunostaining and in situ hybridization. Interestingly, two distinct zones of intensity of 3 beta-HSD localization could be distinguished, namely the highly labeled reticular and fascicular zones and the less positive glomerular zone. This observation coincides with the onset of fetal ACTH secretion on days 17-18 and with accelerated adrenocortical growth and differentiation. After birth and until day 25, strong immunolabeling was observed in the cytoplasm of adrenocortical cells, the glomerular zone being labeled at a lower degree than the remaining cortex. The same localization was obtained by in situ hybridization. This low labeling of the glomerular zone might be related to the low plasma levels of angiotensin II observed in the immature rat. From day 25 after birth, the three zones of the cortex were uniformly labeled and no immunostaining was seen in the medulla or capsule. Similarly, by in situ hybridization, silver grains were located exclusively in the adrenal cortex. The present data suggest that 3 beta-HSD expression could well play a major role in regulating adrenal function during foetal and postnatal development.

3-Hydroxysteroid Dehydrogenases↗
PubMed1991

Immunolocalization of an extracellular domain of connexin43 in rat heart gap junctions.

Antipeptide antibodies directed to residues 55 to 66 (NTQQPGCENVCY) of connexin43 (cx43) specifically recognize this protein on Western blots of intact and urea-split gap junctions isolated from rat heart. These antibodies detect a single protein of 43 kDa, corresponding to cx43, on Western blots of whole fractions of various vertebrate hearts. Immunogold labeling by electron microscopy shows that the epitopes recognized by these antibodies are not localized on the cytoplasmic surfaces of intact gap junctions but only at the edges of these junctions. In urea-split gap junctions the gold particles are seen in the junctional space, associated with the extracellular faces of junctional membranes. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analyses of rat heart gap junctions treated with trypsin show that they are constituted with either two polypeptides of Mr 12,000 and 14,000 or a single polypeptide of Mr 22,000 according to whether the analyses are performed under reducing or non-reducing conditions, respectively. The antibodies directed to residues 55 to 66 of cx43 cross-react with both the 12 and 22 kDa polypeptides. These results suggest that the two protected domains of 12 and 14 kDa which contain the first extracellular loop and a putative second extracellular loop, respectively, are linked by disulfide bonds. In adult rat heart sections analyzed by indirect immunofluorescence the intercalated discs are labeled with antibodies directed to a cytoplasmic carboxy-terminal domain of cx43 (El Aoumari et al., J. Membr. Biol. 115, 229-240 (1990)). The same intercalated discs are also labeled in adjacent sections incubated with the antibodies directed to residues 55 to 66. Two hypotheses might explain these results: either the antibodies have access to the extracellular domain of cx43 molecules localized at the edges of the gap junctions, or cx43 molecules are present in the non-junctional membranes of the intercalated discs.

Amino Acid Sequence↗
PubMed1991

IgA triggers tumor necrosis factor alpha secretion by monocytes: a study in normal subjects and patients with alcoholic cirrhosis.

Under endotoxin-free conditions, peripheral blood mononuclear cells and purified monocytes isolated from healthy control subjects and patients with alcoholic cirrhosis disclose elevated tumor necrosis factor alpha messenger RNA level and produce tumor necrosis factor alpha in response to stimulation by either soluble polymeric IgA or monomeric IgA bound to the surface of culture dishes but not by soluble monomeric IgA. Polymeric IgA induces tumor necrosis factor alpha secretion in a dose-dependent fashion. These results suggest that cross-linking of Fc alpha receptors on human monocytes induces the messenger RNA accumulation and the secretion of the cytotoxic and immunoregulatory cytokine tumor necrosis factor alpha. Furthermore, it is shown that lipopolysaccharide-induced tumor necrosis factor alpha secretion by peripheral blood mononuclear cells is synergistically enhanced in the presence of solid phase monomeric IgA but not in the presence of either soluble monomeric or polymeric IgA. Although increased lipopolysaccharide-induced tumor necrosis factor alpha secretion is observed at baseline in alcoholic cirrhotic patients, this synergism is also expressed in this group of patients. These observations could be of pathophysiological relevance in alcoholic cirrhosis because monomeric IgA deposits along the liver sinusoids and increased serum levels of polymeric IgA are common even in the early stages of this disease.

Female↗
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

Allodeterminants and evolution of a novel HLA-B5 CREG antigen, HLA-B SNA.

A novel HLA-B5 CREG gene, HLA-B SNA was cloned and the primary structure was determined. The sequence data showed that HLA-B SNA was identical to HLA-B51 except the alpha 1 domain in which one amino acid substitution at residue 74 and 5 amino acid substitutions associated with the Bw4/Bw6 epitopes were observed between these Ag. The comparison with other HLA-B locus genes suggested that HLA-B SNA evolved from HLA-B51 by gene exchange or recombination at the exon 2 between HLA-B51 and B8. A total of 10 of 14 HLA-B51-specific CTL clones showed significantly weak or no recognition of HLA-B SNA Ag. They also gave the same degree of a lysis of Hmy2CIR cells expressing the HLA-B35/51 chimeric Ag composed of the alpha 1 domain of HLA-B35 and other domains of HLA-B51 as that of Hmy2CIR cells expressing the HLA-B SNA Ag. These results demonstrated that amino acid substitutions within positions 77-83 associated with the HLA-Bw4/Bw6 epitopes have an influence on recognition of the HLA-B SNA antigen by HLA-B51-specific CTL.

Alleles↗
PubMed1990

Excessive in vitro bacterial lipopolysaccharide-induced production of monokines in cirrhosis.

The objective of this study was to analyze monokine production by peripheral blood mononuclear cells from patients with alcoholic cirrhosis. The capacity of peripheral blood mononuclear cells and purified monocytes from these patients to produce tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 was investigated. Spontaneous production of tumor necrosis factor alpha, interleukin 6 and interleukin 1 beta was similar in cirrhotic and healthy subjects, but serum levels of interleukin 6 (less than 2 U/ml vs. 9.5 +/- 3 U/ml) and tumor necrosis factor alpha (3.1 +/- 1.2 pg/ml vs. 12.0 +/- 1.2 pg/ml) were significantly higher in cirrhotic patients. However, peripheral blood mononuclear cells or purified monocytes from patients with alcoholic liver cirrhosis, stimulated in vitro with Escherichia coli lipopolysaccharide, displayed a marked increase of tumor necrosis factor alpha, interleukin 1 beta and interleukin 6 secretions compared with healthy controls. A striking feature of this overproduction was its reversibility as assessed by allowing cells to rest in vitro without lipopolysaccharide for 1 to 7 days before stimulation. In such conditions, tumor necrosis factor alpha and interleukin 6 secretions declined to levels present in healthy subjects in whom production remained stable, whereas interleukin 1 beta secretion markedly decreased in both groups to the point where no difference could be seen. This reversible oversecretion of cytokines after lipopolysaccharide stimulation, along with the lack of abnormality of spontaneous cytokine secretion, suggests that monocytes in these patients may have undergone an in vivo activation process analogous to a priming phenomenon. The in vitro activation with lipopolysaccharide may represent the correlate of in vivo endotoxemia observed during acute events such as sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1990

Conservation of a cytoplasmic carboxy-terminal domain of connexin 43, a gap junctional protein, in mammal heart and brain.

According to the sequence of connexin 43, a cardiac gap junctional protein, the domain contained within residues 314-322 is located 60 amino acids away from the carboxy-terminus. Antibodies raised to a peptide corresponding to this domain label a unique 43-kD protein on immunoblots of both purified gap junctions and whole extracts from rat heart. Immunofluorescence investigations carried out on mammal heart sections reveal a pattern consistent with the known distribution of intercalated discs. Immunogold labeling performed with ultrahin frozen sections of rat heart or partially purified rat heart gap junctions demonstrate that antigenic determinants are associated exclusively with the cytoplasmic surfaces of gap junctions. The antibodies were shown to cross-react with a 43-kD protein on immunoblots of whole extracts from human, mouse and guinea pig heart. However, no labeling was seen when heart of lower vertebrates such as chicken, frog and trout, was investigated. These results, confirmed by immunofluorescence investigations, were interpreted as a loss of antigenic determinants due to sequence polymorphism of cardiac connexin 43. Proteins of Mr 43 and 41 kD, immunologically related to cardiac connexin 43, were detected in immunoblots of mouse and rat brain whole extracts. mRNAs, homologous to those of cardiac connexin 43 and of the same size (3.0 kb), are also present in brain. Immunofluorescence investigations with primary cultures of unpermeabilized and permeabilized mouse neural cells showed that the antigenic determinants recognized by the antibodies specific for connexin 43 are cytoplasmic and that the labeling observed between clustered flat cells, is punctate, as expected for gap junctions. Double labeling experiments demonstrated that the immunoreactivity is associated with GFAP-positive cells, that is to say, astrocytes.

Amino Acid Sequence↗