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J Testart

Publications and source records attributed to J Testart.

At least 109 records · Page 6Linked to original sources
PubMed1991

Distribution and characterization of endogenous benzodiazepine receptor ligand (endozepine)-like peptides in the rat gastrointestinal tract.

Endozepine is the generic name for a family of peptides that are capable of displacing benzodiazepines and the 3-carboxylate ester of beta-carboline from their specific binding sites on synaptosomal membranes. The 104-amino acid polypeptide diazepam-binding inhibitor (DBI) and the octadecaneuropeptide (ODN) generated by tryptic digestion of DBI are two members of the endozepine family. In the present study we have used RIA, HPLC, in situ hybridization, and immunohistochemical techniques to identify and localize endozepine-like molecules in the rat gastrointestinal tract. Significant amounts of endozepine-like immunoreactivity (LI) were detected throughout the gut; the highest concentrations were found in the duodenum and antrum. HPLC analysis revealed that the immunoreactive material eluted as a major peak with a higher retention time than that of synthetic ODN. The distribution of the immunoreactive peptide(s) was studied using the peroxidase-antiperoxidase technique at the light microscope level. Endozepine-LI was localized only in the epithelial cell layer of the intestine in both goblet cells and enterocytes. In the stomach, endozepine-LI appeared to be restricted to deep layer of the epithelial cells. The diffuse neuroendocrine cells (amine precursor uptake and decarboxylation system) as well as myenteric and neuronal cells were devoid of immunoreactivity. A good correlation was observed between RIA and immunocytochemical data, in that the esophagus, which contained very low concentrations of endozepine-LI, also exhibited weak immunostaining of secretory cells. In situ hybridization using a 35S-labeled cRNA probe showed that endozepine mRNA was located in the mucosa. Taken together, these results show that in the rat, epithelial cells synthesize endozepine-LI material. Since epithelial cells also contain a high density of peripheral-type benzodiazepine-binding sites, our data indicate that endozepines may play a role in water, electrolyte, and/or mucus regulation in the rat gastrointestinal tract. The occurrence of high levels of endozepine-LI in the rat stomach also suggests that endozepines can be involved in the regulation of gastric acid secretion through modulation of local gamma-aminobutyric acid-ergic neurotransmission.

Animals↗
PubMed1991

Sequential transformations of human sperm nucleus in human egg.

In-vitro insemination of human zona-free oocytes prepared from oocytes that failed to fertilize in an in-vitro fertilization programme was used as an experimental model to study the time course and morphological events during the development of sperm nuclei into male pronuclei. At 30 min after insemination, 22 eggs were cultured in a CO2 incubator for further 3.5 h and 17 eggs were placed individually between a slide and coverslip for randomly repeated microscopical observations in a controlled environment for at least 3.5 h. Simultaneous arrest of maternal meiosis and sperm nuclear development occurred in 36.4% (8/22) eggs cultured in the CO2 incubator and 47.1% (8/17) of those cultured between a slide and coverslip. Sequential transformation of the human sperm nucleus in human eggs was studied in 6 eggs that showed continuous development of sperm nuclei into male pronuclei during at least 3.5 h after insemination. The early sperm nuclear development in human egg ooplasm can be divided into three phases: the sperm nucleus first decondenses (phase 1) then partly recondenses (phase 2) before expanding again to form an early male pronucleus (phase 3). The prepronuclear stages (phases 1 and 2) took about 60 min each and the pronuclear formation (phase 3) began between 120 and 170 min after insemination. Early pronuclear formation was associated with the occurrence of dense outline material, probably a precursor of the future pronuclear membrane, around the recondensed nucleus in re-expansion (phase 3). Between 30 and 60 min after the beginning of phase 3, numerous (greater than 20) dense grains, considered as nucleolar precursors, were clearly visible inside the growing male pronucleus. Moreover, we have examined sperm nuclear changes in some eggs in which the progression of late meiosis was abnormal. Meiotic arrest of maternal chromatin was always associated with arrest of sperm head development. In 75% (6/8) of the eggs arrested in the metaphase II stages and in 87.5% (7/8) of the eggs arrested in late anaphase II, sperm nuclear development was stopped at the decondensed and recondensed stages, respectively. We have always observed male pronuclei when a maternal pronucleus was present in the egg. These observations suggested that maternal chromatin and sperm nuclear development are probably regulated by common factor(s).

Cell Nucleus↗
PubMed1991

Could recurrent cholangitis after Roux-en-Y hepaticojejunostomy be explained by motor intestinal anomalies? A manometric study.

The aim of this study was to describe the motor patterns found in two patients with recurrent cholangitis episodes after Roux-en-Y hepaticojejunostomy. In one patient, cholangitis was due to a stenosis of the anastomosis between the limb and the left intrahepatic bile duct, while motility of the limb, duodenum, and distal jejunum was normal. In the second patient, no anatomical explanation was found for cholangitis attacks. However, although the duodenal motor activity was normal, the motility of the limb and of the jejunum below the jejunojejunal anastomosis was grossly abnormal: permanent minute rhythm, phase IIIs absent or rare and slowly propagated, all motor abnormalities that could promote bacterial overgrowth in the limb. This stresses the interest in performing motor studies of the Roux-limb when cholangitis remains unexplained after Roux-en-Y hepaticojejunostomy.

Anastomosis, Roux-en-Y↗
PubMed1991

[Collis's operation for brachyesophagus. (49 patients)].

The results of infradiaphragmatic Collis' gastroplasty for the treatment of gastroesophageal reflux associated with acquired short brachyesophagus (Barrett's esophagus) were prospectively studied in 49 patients (50 operations). Clinical and endoscopic findings, and 3-hour postprandial pH measurement including Kaye's score were evaluated at short (3 to 8 months), medium (1 to 4 years), and long-term (more than 4 years) for all patients. Postoperative morbidity was 16 percent; there were 3 deaths (6 percent). Short term results, evaluated in 45 patients, were considered satisfactory in 30, poor (pyrosis and esophagitis) in 2, and incomplete (pyrosis without esophagitis in 2, dysphagia in 5, mild esophagitis in 6) in 13. Long term results (32 patients) were satisfactory in 24, poor in 5, and incomplete in 3 (pyrosis without esophagitis in one, gastric outlet disorder in 2). Long term pH measurements were obtained in 21 patients: 3 out of 6 patients with high scores had clinical or endoscopic signs of esophagitis. Analysis of late results showed that: a) satisfactory short term outcome was maintained in all but 2 patients (deterioration was observed in one patient 4 years later because of aggressive treatment for terminal bronchopulmonary carcinoma; the other was observed 5 years later after steroid therapy for aspergilloma with severe asthma); b) pH scores were variable in 11 patients. This variability and discordance of pH measurements was most likely due to the presence of acid secretion above the new esogastric junction, which was observed in half of the cases. We conclude that Collis' gastroplasty provided good results in Barrett's esophagus and might be compared to duodenal diversion in ulterior studies in this setting.

Adolescent↗
PubMed1991

[Leiomyosarcoma of the inferior vena cava. Report of 3 cases].

Three cases of leiomyosarcoma of the inferior vena cava are reported. With the help of a review of the literature, the value of ultrasonography, computed tomography and cavography is recalled. Surgical possibilities and results are described together with the necessity of adjuvant treatments.

Echinococcosis, Hepatic↗
PubMed1990

[Artificial insemination].

The first artificial inseminations (AI), performed some 200 years ago, took place during menstruations since the ovulation and fertilization processes were then totally unknown. Nowadays, AI is usually carried out during the "ovulation period", which means a lack of accuracy in the estimated gametes meeting time which may reach several days. We formulate the hypothesis, supported by an analysis of international results, that AI is more effective when performed at the time of, or soon after follicular rupture, i.e. 36 to 48 hours after an endogenous (LH surge) or exogenous (hCG injection) induction, especially in case of male infertility. Under these conditions, it seems that intrauterine (rather than intracervical) AI performed after ovarian stimulation (and not in a spontaneous cycle) helps solve the problems of many infertile women before a more complex medical assistance is contemplated.

Female↗
PubMed1990

Influence of human menopausal gonadotropin on the recruitment of human ovarian follicles.

Human menopausal gonadotropin (hMG) was administered once (225 IU) to 16 women during different phases of the menstrual cycle: either late-luteal, early-follicular, midfollicular, or late-follicular phases before surgical ovarian resection or ablation. The mitotic index (MI) of follicular granulosa cells and the proportion of recruitable healthy follicles were analyzed 4 to 5 days after hMG injection, the findings being compared with those in unstimulated ovaries from 22 normally cycling patients. The percentages of healthy recruitable follicles greater than or equal to 2 mm in diameter was not altered by hMG as compared with controls. The granulosa cell MI was highly stimulated by hMG when administered in late-luteal or early-follicular phases; however, no granulosa cell MI stimulation was noted when hMG was administered in the midfollicular or late-follicular phases. The progressive abolition of the ability of hMG to stimulate follicular growth as ovulation approaches supports the existence of an inhibitory activity (possibly ovarian) designed to suppress the selection and the maturation of the less developed antral follicles from the midfollicular phase of the spontaneous human menstrual cycle.

Adult↗
PubMed1990

Reversible inhibition of fertility in mice by passive immunization with anticumulus oophorus antibodies.

The mucified cumulus oophorus represents an outer enveloping layer around ovulated mammalian oocytes. This coat in its definitive expanded form appears late in the preovulatory development as a result of intensive secretion of intercellular matrix by cumulus cells. We have shown recently that antibodies to the cumulus matrix inhibit human fertilization in vitro. This study was undertaken to assess, in an animal model, the effects of anticumulus oophorus antibodies on fertility by use of different passive immunization protocols. A purified anticumulus immunoglobulin fraction was prepared from hyperimmune rabbit serum and administered at different times before and after mating to mice superovulated with equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG). A dose-dependent negative effect of this anticumulus antibody preparation on the number of fertilized eggs recovered from the oviducts of treated animals was observed when the antibodies were given before mating. High antibody doses also interfered with oocyte maturation and ovulation if applied on the day of eCG treatment, but no effects on these processes were found when the antibodies were given on the day of hCG treatment. The antifertility effect of anticumulus antibodies was reversible and the antibodies did not affect postfertilization development. These findings make cumulus oophorus antigens serious candidates for the development of a contraceptive vaccine.

Animals↗
PubMed1990

Acrosin activation follows its surface exposure and precedes membrane fusion in human sperm acrosome reaction.

Evidence has accumulated suggesting multiple roles of acrosin in fertilization, including its participation in early steps of gamete recognition and binding. However, the implication of acrosin in many of these processes is not compatible with its presumptive sequestration within the sperm acrosome until a late phase of the acrosome reaction. In an earlier study (J. Tesarik, J. Drahorad, J. Peknicova, 1988, Fertil. Steril. 50, 133-141), we reported the binding of an anti-acrosin monoclonal antibody (MO-AKR.1) to the plasma membrane overlying the acrosome of human spermatozoa starting the acrosome reaction. In this study, we characterized further this antibody with regard to its reactivity with different forms of acrosin and found that it recognizes specifically an active form of this enzyme and does not react with its proenzyme form. MO-AKR.1 was thus used as a probe for in situ analysis of acrosin activation during the acrosome reaction. When suspensions of living spermatozoa were incubated with MO-AKR.1 and with another monoclonal antibody (T6) directed to an intra-acrosomal cytoskeletal protein, significantly more spermatozoa reacted with the former antibody than with the latter; this indicated that some of the spermatozoa showing acrosin immunoreactivity carried activated acrosin on the cell surface, while their acrosome was still impermeable to intra-acrosomal-directed probes. The size of this particular sperm subpopulation was increased by the action of follicular fluid (a natural acrosome reaction inducer), but not ionophore A23187 (an artificial acrosome reaction inducer); it corresponded to the proportion of spermatozoa showing acrosin immunoreactivity on the plasma membrane but neither intra-acrosomal staining nor perceptible membrane perturbations when examined by immunoelectron microscopy. When spermatozoa were pre-incubated with protease inhibitors before the addition of acrosome reaction-inducing agents, the percentage of cells binding MO-AKR.1 was markedly reduced. These data suggest that limited acrosin activation on the sperm plasma membrane is an early event in the physiological acrosome reaction.

Acrosin↗
PubMed1990

Effect of the human cumulus oophorus on movement characteristics of human capacitated spermatozoa.

The effect of human cumulus oophorus on movement characteristics of human spermatozoa previously incubated in vitro under capacitating conditions was studied using automated digital image analysis. When spermatozoa were incubated for a short time with whole cumuli, most of those that penetrated the cumulus intercellular matrix were characterized by a linear movement with small amplitudes of lateral head displacement, but with elevated values of beat cross frequency. Short (5 min) incubation with solubilized cumulus intercellular matrix of spermatozoa preincubated in capacitating conditions (6 h) significantly reduced the percentage of spermatozoa showing the 'hyperactivated' type of motility characterized by high curvilinear velocity, low progressive velocity and elevated values of lateral head displacement. Moreover, a subpopulation of spermatozoa with very high values of progressive velocity and beat cross frequency and with reduced amplitudes of lateral head displacement appeared in these conditions. This cumulus-related motility pattern was not seen in fresh spermatozoa or in those incubated in the absence of cumulus material. Changes in the sperm movement characteristics similar to those observed in the presence of the solubilized cumulus matrix could also be induced by some of its h.p.l.c. fractions. These results show that the intercellular matrix of the human cumulus oophorus exerts a specific effect on human sperm motility, probably acting preferentially on the 'hyperactivated' sperm subpopulation.

Cells, Cultured↗
PubMed1990

Effects of prolonged administration of anti-cumulus oophorus antibody on reproduction in mice.

Mice were passively immunized over 6 weeks with contraceptive doses of an anti-cumulus oophorus antibody preparation. The persistence of oestrus, accompanied by complete inhibition of conception, was observed throughout treatment. After cessation of treatment, fertility was restored within 2 weeks. Histological examination did not reveal any depletion of the ovarian oocyte stock. These results warrant further research into the nature of cumulus antigens and their use in active immunization studies.

Animals↗
PubMed1990

[Primates in the study of oocyte maturation].

In the mammalian oocyte, meiosis is initiated during fetal life. Meiosis proceeds up to the diplotene stage of the first prophase and is arrested at birth and the oocyte presents a nuclear structure known as germinal vesicle (GV). Meiotic arrest persists until sexual maturity, when one or more oocytes, the number dependent on the species, reinitiate their reduction division at each cycle. The series of event, initiated by the breakdown of the germinal vesicle (GVBD) and completed with formation of the polar body, leads to the production of a mature, fertilizable oocyte, and is defined as oocyte maturation. Maturation of the oocyte is an essential prelude to fertilization. Normally the meiosis is reinitiated by the preovulatory LH peak but when meiotically arrested oocytes are removed from the antral follicles, they resume meiosis spontaneously in vitro. However primate (human and monkeys) oocytes isolated from antral follicles and cultured within their cumuli for two days, spontaneously resumed meiosis at a very low rate (less than 30%) compared to other mammals. Cynomolgus monkey oocyte then appears as a good model for in vitro studies of maturation initiation. Follicular atresia improve significantly the GVBD rate (about 50%). The cumulus cell mass takes an important part in the maintenance of the meiotic arrest since its mechanical removal is followed by an increase of the GVBD (P less than 0.02). A gonadotropin releasing hormone agonist (GnRHa) and a protein kinase C activator added to the culture medium both improve the GVBD (54% and 55% respectively, P less than 0.01). The GnRHa oocyte maturation induction is probably protein kinase C dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[The role of colorectal resection in severe constipation after promontory rectopexy].

Abdominal rectopexy to the promontory is an effective treatment for total rectal prolapse, internal procidentia and solitary ulcer. This paper is designed to stress the risk of severe constipation following rectopexy, a complication which required surgical resection in 5 cases. This raises the problems of the physiological mechanisms of this complication, the definition of a possible high risk population (young women, patients who were constipated preoperatively?), and an alternative to promontory rectopexy: sacral fixation of the rectum, associated sigmoidectomy, Delorme's operation?

Adult↗
PubMed1990

[Physiopathology of the cerebral arterial circulation. Application to cerebro arterial surgery].

Autoregulation of cerebral arterial circulation corresponds to a hemodynamic reserve enabling normal cerebral blood flow to be assured when arterial blood pressure drops. However, the capacity of this autoregulatory system is exceeded when pressure drops below 60 +/- 10 mmHg, at which time metabolic disturbances appear followed by the arrest of electric activity and the death or neurons. These ischemic phenomena involve more or less extended regions: cerebral or choroidal arterioles or arteries, or even those of the entire brain. They can occur in series as, for example, the embolism of a cerebral arteriole or artery in a brain already globally hypoperfused downstream from a carotid occlusion or narrow stenosis. The association of these phenomena accounts for the different clinicopathologic cerebrovascular accidents. These disturbances of cerebral blood flow can be explored clinically by isotopic techniques. A cerebral perfusion blood pressure drop can be suspected, when nonhemispheric symptoms appear, on the basis of ophthalmodynamometry, oculoplethysmography or changes in intracranial arterial velocity (transcranial Doppler examination) during the Diamox (Acetazolamide) test. After release of carotid clamping or correction of a "hemodynamically significant" stenosis, increased cerebral blood flow can be observed, with sometimes a "cerebral hyperperfusion" syndrome similar to that of hypertensive events which exceed the capacities of cerebral arterial autoregulation.

Brain Ischemia↗
PubMed1990

[Repeated subinguinal bypass. Report of 85 cases].

From 1975 to 1987, 68 patients were operated with repeated subinguinal bypass (SIB) following early or late thrombosis os an initial bypass graft; 10 were operated with a third SIB, 4 with a fourth SIB. The indication for the second SIB was acute ischemia in 15 cases and chronic ischemia in 53. The graft material used was venous in 21 cases, prosthetic in 29 cases and mixed in 53. The distal anastomosis was performed on the upper popliteal artery in 12 cases, the lower popliteal artery in 34 cases or an artery in leg in 22 cases. The actuarial permeability rate of 84 repeated SIBs, whatever the material, was 21.7% at 1 year (50.2% for venous grafts and 13.6% for prosthetic grafts). The limb preservation rate was 47.9% at 5 years. Operative mortality was about 1%. The analysis of the results suggests that the repeated SIB should be performed only: for limb salvage, if the downstream arterial bed is in good condition, with usable venous material. The risk of having to perform a thigh amputation rather than a leg amputation when attempting repeated SIB is of 13.9% only.

Actuarial Analysis↗