Biomedical subjects

E Dupont

Publications and source records attributed to E Dupont.

At least 127 records · Page 7Linked to original sources

PubMed1992

Ontogeny and subcellular localization of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) in the human and rat adrenal, ovary and testis.

Primates are unique in having adrenals that secrete large amounts of the precursor sex steroids (PSS) dehydroepiandrosterone (DHEA) and especially DHEA-sulfate. The adrenal PSS require the action of 3 beta-hydroxysteroid dehydrogenase/5-ene-4 ene isomerase (3 beta-HSD), 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD), 5 alpha-reductase and/or aromatase to form the androgen dihydrotestosterone (DHT) or the estrogens 17 beta-estradiol and androst-5-ene-diol. Knowing the crucial role of 3 beta-HSD and 17 beta-HSD in sex steroid biosynthesis both in classical as well as in peripheral steroidogenic tissues, we have concentrated our efforts on the elucidation of the molecular structure of these enzyme families. We have thus characterized two types of human 3 beta-HSD cDNA clones and their corresponding genes which encode deduced proteins of 371 and 372 amino acids and share 93.5% homology. Human type I 3 beta-HSD is the almost exclusive mRNA species expressed in the placenta and skin, while human type II is the predominant mRNA species in the adrenals, ovaries and testes. We have also recently elucidated the structure of three types of rat 3 beta-HSD cDNAs which all encode a 372 amino acid protein. The predicted rat type I and II 3 beta-HSD proteins expressed adrenals, gonads and adipose tissue share 94% homology while they share 80% similarity with the liver-specific type III 3 beta-HSD. Transient expression of human type I and II as well as rat type I and II 3 beta-HSD cDNAs in HeLa human cervical carcinoma cells reveals that 3 beta-ol dehydrogenase and 5-ene-4-ene isomerase activities reside within a single protein and that these cDNAs encode functional 3 beta-HSD proteins. The expressed rat type III protein possesses a unique property catalyzing selectively the reduction of 3 beta-androstane 5 alpha-steroids such as DHT. Furthermore, we have also demonstrated by site-directed mutagenesis that the lower activity of expressed rat type II compared to rat type I 3 beta-HSD protein is due to a change of four amino acid residues potentially involved in a membrane-spanning domain. In parallel, we have characterized the complete nucleotide sequence of human 17 beta-HSD cDNA clones encoding a 327 amino acid protein as well as two in tandem 17 beta-HSD genes. Two major 17 beta-HSD mRNA species have been detected in several tissues due to a tissue-specific alternative site of initiation of transcription.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal Glands↗

PubMed1992

Characterization, expression, and immunohistochemical localization of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase in human skin.

Three beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) catalyses an obligatory step in the biosynthesis of all classes of hormonal steroids, namely, the oxidation/isomerization of 3 beta-hydroxy-5-ene steroids into the corresponding 3-keto-4-ene steroids in gonadal as well as in peripheral tissues. Because humans are unique with some primates in having adrenals that secrete large amounts of the steroid precursors dehydropiandrosterone (DHEA) and its sulfate (DHEA-S) and its exceptionally large volume makes the skin an important site of steroid biosynthesis, we have isolated and characterized cDNA clones encoding 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase from a human skin lambda gt11 library. The longest clone obtained contains the entire coding sequence for type I 3 beta-HSD (372 amino acids) as well as an additional 131 nucleotides in the 5'-untranslated region. The insert of 1647 bp containing the entire coding region has been inserted in a pCMV expression vector and transfected into human cervical carcinoma cells (HeLa). The expressed enzyme efficiently catalyzes the transformation of pregnenolone, DHEA, and dihydrotestosterone into progesterone, 4-androstenedione, and 5 alpha-androstane-3 beta, 17 beta-diol, respectively. Using the enzyme expressed in HeLa cells, we have shown cyproterone acetate, a progestin used in the treatment of acne and hirsutism, as well as norgestrel and norethindrone, two steroids widely used as oral contraceptives, to be relatively potent inhibitors, with Ki values of 0.38 microM, 1.3 microM, and 1.2 microM, respectively. Immunohistochemical localization of 3 beta-HSD, illustrated by using an antibody raised against human placental 3 beta-HSD, shows that the enzyme is localized in sebaceous glands.

Amino Acid Sequence↗

PubMed1992

Driving with Parkinson's disease. A controlled laboratory investigation.

The part played in traffic safety by illness or disability is unknown, as is the identity and degree of the disorders which necessitate the use of driving aids or completely incapacitate a person from driving. By means of a mock car, 28 persons suffering from Parkinson's disease were compared with 109 healthy controls. Only patients in presumed optimal drug regimen and without complicating disorders were included in the study group. The main results were failure to react to stimuli on several occasions, a high frequency of erroneous reactions in particular directional errors, reduced strength and speed of movement and increased reaction times. Typically the latter would entail a prolongation of the reaction distance with more than 1/3, i.e. 6 m when driving a car at a speed of 80 km/h. The Webster score proved to be an unreliable predictor of the results of the mock car test, and the UPDRS is suggested for future studies.

Accidents, Traffic↗

PubMed1992

TCR V alpha- and V beta-gene segment use in T-cell subcultures derived from a type-III bare lymphocyte syndrome patient deficient in MHC class-II expression.

Previously, we and others have shown that MHC class-II deficient humans have greatly reduced numbers of CD4+CD8- peripheral T cells. These type-III Bare Lymphocyte Syndrome patients lack MHC class-II and have an impaired MHC class-I antigen expression. In this study, we analyzed the impact of the MHC class-II deficient environment on the TCR V-gene segment usage in this reduced CD4+CD8- T-cell subset. For these studies, we employed TcR V-region-specific monoclonal antibodies (mAbs) and a semiquantitative PCR technique with V alpha and V beta amplimers, specific for each of the most known V alpha- and V beta-gene region families. The results of our studies demonstrate that some of the V alpha-gene segments are used less frequent in the CD4+CD8- T-cell subset of the patient, whereas the majority of the TCR V alpha- and V beta-gene segments investigated were used with similar frequencies in both subsets in the type-III Bare Lymphocyte Syndrome patient compared to healthy control family members. Interestingly, the frequency of TcR V alpha 12 transcripts was greatly diminished in the patient, both in the CD4+CD8- as well as in the CD4-CD8+ compartment, whereas this gene segment could easily be detected in the healthy family controls. On the basis of the results obtained in this study, it is concluded that within the reduced CD4+CD8- T-cell subset of this patient, most of the TCR V-gene segments tested for are employed. However, a skewing in the usage frequency of some of the V alpha-gene segments toward the CD4-CD8+ T-cell subset was noticeable in the MHC class-II deficient patient that differed from those observed in the healthy family controls.

Base Sequence↗

PubMed1992

Immunocytochemical localization of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase in human ovary.

The enzyme complex 3 beta-hydroxy-5-ene-steroid dehydrogenase and steroid delta 5----4-ene-isomerase (3 beta HSD) is involved in the biosynthesis of all classes of active steroids, namely glucocorticoids, mineralocorticoids, progesterone, and sex steroids. To obtain more information about the age-specific expression of 3 beta HSD in the human ovary, we have localized this enzyme by immunocytochemistry at the light microscopic level during fetal and postnatal periods of development in the human. Immunocytochemical localization was achieved using specific polyclonal antibodies developed against purified human placental 3 beta HSD. In the fetal ovary of 28-34 weeks, specific immunostaining for 3 beta HSD was exclusively detected in thecal cells surrounding primary follicles and in interstitial cells. From birth until puberty, no significant immunostaining for 3 beta HSD could be observed, while from puberty to menopause, staining was detected in theca interna cells as well as granulosa cells of growing follicles. The intensity of staining in the theca interna cells was always much higher than that in granulosa cells. Immunostaining was also found in the cytoplasm of luteinized granulosa and theca interna cells of the corpus luteum. Interestingly, there was an absence of immunoreactivity for 3 beta HSD in one to several layers of theca interna cells lying just beneath the basement membrane. These negative cells may correspond to fibroblast-like cells that are devoid of 3 beta HSD activity. In postmenopausal ovaries, immunolabeling was only found in dispersed interstitial cells, thus suggesting that the ovaries of postmenopausal women might be involved in sex steroid hormone secretion.

Aged↗

PubMed1992

Immunohistochemical localization of 3 beta-hydroxy-5-ene-steroid dehydrogenase/delta 5----delta 4 isomerase in human placenta and fetal membranes throughout gestation.

The regulation of steroid production by the placenta and fetal membranes is important for both the maintenance of pregnancy and the timing of parturition. 3 beta-Hydroxy-5-ene-steroid dehydrogenase/delta 5----delta 4-isomerase (3 beta HSD) catalyzes an obligatory step in the biosynthesis of steroid hormones. We have determined the localization of 3 beta HSD in the human placenta, fetal membranes, and umbilical cord throughout gestation by immunohistochemical analysis, using a polyclonal antibody raised in rabbits against a purified preparation of human placental 3 beta HSD. In placenta, immunoreactive (IR-) 3 beta HSD was localized in the syncytiotrophoblast and intermediate trophoblast cells at both villous and extravillous sites, but not in cytotrophoblast cells from 6 weeks gestation to term. At 6-7 weeks gestation, IR-3 beta HSD was distributed in the cytoplasm of syncytiotrophoblast in about half of placental villi. By 12-14 weeks, the syncytiotrophoblast of all placental villi stained positively for 3 beta HSD. In the fetal membranes, strong IR-3 beta HSD staining was found in the trophoblast and reticular layers of chorion and in invasive trophoblast cells in decidua, and weakly in decidual stromal cells and amniotic epithelium. No IR-3 beta HSD was found in amnion on the placental plate, but in the umbilical cord, IR-3 beta HSD was present in the amniotic epithelium and also in fibroblast cells in Warton's jelly. These observations demonstrate that the localization of 3 beta HSD immunoreactivity and, therefore, the presumed sites of delta 5- to delta 4-steroid interconversion throughout gestation are principally the syncytiotrophoblast and intermediate trophoblast cells in placenta and the trophoblast cells in chorion and decidua in fetal membranes.

Extraembryonic Membranes↗

PubMed1992

Administration of anti-TNF antibody improves left ventricular function in septic shock patients. Results of a pilot study.

In this pilot study, murine monoclonal anti-TNF antibody (2 mg/kg) was administered to ten patients within 24 h of septic shock which persisted after initial resuscitation with intravenous fluids and adrenergic agents. This treatment resulted in a reduction in heart rate (from 122 +/- 10 to 113 +/- 10 beats per minute at 4 h, p less than 0.01) associated with an increase in LVSWI (from 26.5 +/- 5.6 to 31.5 +/- 10.5 g.m2 at 2 h, p less than 0.05), indicating in the absence of change in cardiac filling pressures, an improvement in ventricular function. Arterial oxygenation improved concurrently in six patients. These changes, however, appeared transient. The improvement in cardiac function following anti-TNF antibody administration in patients is in keeping with recent experimental studies indicating the role of TNF in the myocardial depression characterizing septic shock.

Aged↗

PubMed1992

[Anti-neutrophil cytoplasmic antibodies (ANCA): major progress in the diagnosis of vasculitis].

ANCA antibodies represent a family of autoantibodies directed against neutrophil enzymes. Immunofluorescence patterns allow to distinguish c-ANCAs from p-ANCAs. The detection of ANCAs is often a key element for the diagnosis of Wegener's granulomatosis, microperiarteritis, Churg-Strauss syndrome and idiopathic rapidly progressive glomerulonephritis. Although the pathogenic role of ANCAs is not firmly established, their detection often allows an early therapeutic decision in necrotizing vasculitides.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1992

[Immunotherapy of recurrent spontaneous miscarriages (idiopathic abortive disease): preliminary results].

Recurrent spontaneous abortion (greater than or equal to 3 spontaneous miscarriages) represents an entity defined by negative criteria (absence of anatomical, hormonal, autoimmune and chromosomal abnormalities). The immune hypothesis is corroborated by the successes (greater than or equal to 80 %) of specific (paternal leucocytes) or non-specific (intravenous gammaglobulins) immunotherapeutic trials. Studies on the mechanisms of action of those two methods will afford information on the pathogenesis of this condition.

Abortion, Habitual↗

PubMed1992

Differential effects of pentoxifylline on the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) by monocytes and T cells.

Pentoxifylline (PTX) is a methylxanthine compound known to inhibit the production of tumour necrosis factor-alpha (TNF-alpha) by monocytic cells. In this study, we found that PTX differentially regulates the production of TNF-alpha and interleukin-6 (IL-6). Indeed, PTX at high concentrations triggers the production of IL-6 but not of TNF-alpha by peripheral blood mononuclear cells (PBMC). Further experiments indicated that monocytes are responsible for this PTX-induced IL-6 production. When PBMC were stimulated with LPS, PTX was found to inhibit the secretion of TNF-alpha as well as the accumulation of TNF-alpha messenger RNA (mRNA). In contrast, no inhibitory effect was observed on the induction of IL-6. Similar results were obtained when PBMC were stimulated with OKT3 monoclonal antibody (mAb). In addition, the in vivo administration of PTX in transplant patients receiving the first dose of OKT3 allowed to decrease the systemic release of TNF-alpha but not of IL-6. Since monocytes represent a major source of TNF-alpha and IL-6 in these settings, additional experiments were performed in vitro on purified T cells stimulated with the CLB-T3/3, an anti-CD3 mAb which does not require the presence of accessory cells to activate T cells. In this system, PTX was found to inhibit the secretion of both TNF-alpha and IL-6 by T cells. We suggest that cAMP could be involved in these differential effects of PTX on production of TNF-alpha and of IL-6.

Antigens, CD↗

PubMed1992

[Creation of a planned autologous transfusion unit in a hospital distinct from a transfusion center].

Autologous blood predonation now widely used for programmed surgery has been recently regulated by a law from january 9 1992. It establishes that the procedure must be performed under the responsibility of an accredited blood transfusion center. This work discloses that the establishment of an autotransfusion unit in a hospital endowed with an active surgical program is feasible, the major objective being improvement of the quality of life of elderly patients with invalidating diseases. We report the one year experience of a collaboration between the Braine-l'Alleud-Waterloo hospital and the Red Cross Erasme-Brabant Wallon blood transfusion center. Eighty patients enrolled in programmed surgery consisting mostly in orthopedic surgery have given 187 units of packed red blood cells and fresh frozen plasma. Sixty two patients (83%) were transfused solely with autologous blood. Tolerance was excellent as only 4 slight malaise episodes were observed. Our study also indicates that programmed predonation should be proposed mainly to patients for whom the prescribed blood is effectively transfused. Creation of such autotransfusion units in hospitals distinct from a blood transfusion center is feasible with the deep collaboration between physicians in charge of the patients, the hospital laboratory and the blood transfusion center.

Adult↗

PubMed1992

[Recurrent spontaneous miscarriage].

Spontaneous recurrent miscarriages still represent a poorly defined entity. It is commonly accepted that they include early (1st trimester) spontaneous abortion thus excluding those related to well documented chromosomal, anatomical, hormonal or autoimmune causes such as SLE or anticardiolipin syndrome. There is also a general consensus based upon historical series to require at least three consecutive miscarriages. In a series of 58 consecutive couples with recurrent miscarriages studied at the clinics of immunology of pregnancy, a careful investigation could demonstrate the high incidence of anatomical abnormalities detected by hysterosalpingography and consisting mostly of uterus bicornis or uterus septus. This finding emphasises the importance of this examination. Some of these cases required surgical or endoscopic therapy. Only one patient displayed chromosome abnormalities excluding her from the definition of spontaneous recurrent miscarriage. The other patients were treated either with paternal leucocytes or gammaglobulins.

Abortion, Habitual↗

PubMed1992

[Alloimmune neonatal thrombocytopenia].

Neonatal alloimmune thrombocytopenia (NAIT) is due to fetomaternal incompatibility for platelet specific antigens, most frequently HPA-1a (PLA1) and HPA-5b (BRa). It occurs in approximately 1/2.000-1/5.000 births. The most serious complication of NAIT is intracranial hemorrhage. The risk of life-threatening hemorrhage must lead to prompt diagnosis and effective therapy. Improvements in antenatal diagnosis and in utero therapy facilitate appropriate management of pregnancy at risk for NAIT. We report our experience with the serological diagnosis of 14 NAIT cases using new performing techniques such as western blotting (WB) and MAIPA (monoclonal antibody specific immobilization of platelet antigens).

Antigens, Human Platelet↗

PubMed1992

[Immunological selection of bone marrow donors].

In the last twenty years bone marrow transplantation has become the treatment of choice for many hematological malignancies and immunologic defects. The ideal donor is a perfectly HLA-identical family member. Given the limited proportion of patients who can benefit of such a donor, unrelated bone marrow donors are increasingly being used. The immunological methods of selection used for siblings have been shown to be inadequate for the new type of donors. New techniques of molecular biology detecting a new micropolymorphism have been developed. This paper discusses the techniques and interpretations of the immunological tests of selection.

Bone Marrow Transplantation↗

PubMed1991

Lack of association between HLA-DR antigens and sleep-onset REM periods in major depression.

Narcolepsy is the disease disclosing the strongest association with the HLA system. Almost 100% of cases are associated with HLA-DR2 antigen. Moreover, narcolepsy is often characterized by the occurrence of sleep-onset REM (SOREM) periods. SOREM has also been demonstrated in major depression. To further investigate the relationship between SOREM and HLA-DR2, HLA-DR and HLA-DQ antigens were assessed in 50 research diagnostic criteria (RDC) major depressed patients. Depressed patients were elected for HLA typing on the basis of the presence of at least one SOREM period (n = 29) or three REM latencies above 50 min (n = 21) during three consecutives EEG nights recording. No significant differences were observed in the frequency of HLA-DR or HLA-DQ antigens between patients and controls. These results demonstrate a lack of association between SOREM and HLA-DR2 in major depression, and also do not confirm the presence of an association between antigens encoded by the HLA region of the chromosome 6 and major depressive illness.

Adult↗

PubMed1991

[Favourable effects of some HLA-DR disparities on kidney graft survival. Proposal for a new recipient selection policy].

In a previous retrospective study conducted from 1980 to 1987 on 275 renal cadaveric transplants, we have shown that HLA-DR disparities between donor and recipient exerted differential effects on graft survival. Thus, the presence of DR4, DR5 and DR7 in the donor, or of DR5 in the recipient was associated with an excellent survival, whereas disparities due to the presence of DR1 and DR2 in the donor, or of DR2, DRw6 and DR7 in the recipient were detrimental for the graft. A prospective study on 158 renal cadaveric transplants performed from 1988 to 1990 yielded results that were similar to those of the retrospective study. Graft survival at 18 months was similar in recipients who had either the same DR antigens as those present in their donor or beneficial DR disparities only (83-90 percent), and significantly higher than in recipients with DR detrimental disparities only (62-65 percent). Graft survival in recipients with either mixed or neutral DR disparities occupied an intermediate position (77-78 percent). In conclusion, grafts with excellent outcome, similar to that observed in DR identical pairs, may be proposed to an ever increasing number of patients awaiting a renal transplant by adopting a selection policy based on the choice of beneficial DR disparities when a DR identical recipient is not available in the pool.

Actuarial Analysis↗

PubMed1991

[Apomorphine in the treatment of Parkinson disease].

In later stages of the disease, patients with Parkinson's disease treated with levodopa may become severely disabled by pronounced and sudden motor fluctuations called "the on-off syndrome". In spite of optimal individual adjustment of doses and combinations, orally administered antiparkinson drugs are often not able to eliminate the off-conditions which may last from minutes to hours and sometimes are accompanied by dystonic pain. Apomorphine, a potent dopamine receptor agonist, administered subcutaneously as single injections or continuously by means of a pump, quickly passes on to striatal dopamine receptors. With suitable individually adjusted doses, a rapid, and in some cases, more stable anti-parkinson effect may be achieved. Peripheral side-effects can be avoided by concomitant treatment with domperidone. Nine levodopa treated patients with Parkinson's disease and severe on-off syndrome received apomorphine. Seven experienced considerable and long-term improvement of the disabling symptoms, and some patients reduction of levodopa and/or bromocriptine doses. Treatment with apomorphine should only be considered in patients whose on-conditions are not accompanied by pronounced dyskinesias and/or impairment of balance or to patients suffering from severe dystonic pain.

Adult↗

PubMed1991

Affinity purification of a rat-brain junctional protein, connexin 43.

Immunocytochemical investigations have previously shown that antibodies specific for mammal connexins labeled in situ rat and mouse brain gap junctions. However brain gap-junction proteins have neither been identified with certainty, nor purified. By immunoblotting, anti-peptide antibodies directed against rat heart connexin 43 (CX43) detect a major protein of 41 kDa in rat brain homogenates. The specificity of these antibodies made it possible to establish an affinity-chromatography purification procedure of the 41-kDa protein. Purified antibodies specific for the sequence SAEQNRMGQ (residues 314-322) of rat heart CX43 were covalently bound to a protein-A-Sepharose-CL-4B matrix. Rat brain homogenates were recycled through the immunomatrix and the material specifically bound to the matrix was then competitively eluted with the peptide SAEQNRMGQY. Analysis by SDS/PAGE of eluates demonstrated that they contain a 41-kDa protein associated with low amounts of high-molecular-mass proteins. By immunoblotting, these proteins were shown to be specifically recognized by antibodies directed against residues 5-17, 55-56, and 314-322 of rat heart CX43. The NH2-terminal partial sequence for the 41-kDa protein was determined by microsequencing and shown to be similar to alpha 1 connexins. This is the first successful purification of a junctional protein from brain tissue and provides direct evidence that the 41-kDa protein is a CX43 gene product.

Amino Acid Sequence↗