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Biomedical subjects

G Grignon

Publications and source records attributed to G Grignon.

At least 19 recordsLinked to original sources
PubMed1998

Evaluation of human sperm acrosome reaction and viability by flow cytometry.

We report in this work a quantitative procedure developed to evaluate the acrosomal reaction and vitality of human spermatozoa, with three color staining simultaneously. Twenty normal human sperm were labeled with GB24 monoclonal antibody, a fluorescein isothiocyanate conjugated lectin and propidium iodide (supravital stain). Four conjugated lectins were investigated: WGA, Con-A, PNA and UEA-1. Acrosome reaction was induced with calcium ionophore A-23187. Analyses were made by flow cytometry and electron microscopy. A high percentage of spermatozoa that stained with propidium iodide was found. The results of four lectins show an interaction between GB24 and lectin binding. Significant differences of fluorescence index were obtained between the samples with calcium ionophore A-23187 and the samples without it. The WGA-GB24 association shows an independent behavior and this may depend on the fact that WGA binds to the cytoplasmic membrane of human spermatozoa and GB24 antibody bind inner acrosome membrane. Using Con-A, PNA and UEA-I a crowded staining is likely to occur because these lectins and GB24 antibody mainly bind to acrosome membranes, and our results then show a close relation.

Acrosome Reaction↗
PubMed1996

A morphometric and functional study of the toxicity of atmospheric ammonia in the extrathoracic airways in pigs.

The effects of atmospheric ammonia (NH3) on the nasal and tracheal mucosa of pigs were investigated by morphometric and functional methods. Pigs were exposed to four concentrations of NH3 [5 (control), 25, 50 and 100 ppm] for 6 days in a specially designed air-pollutant exposure chamber. Samples were taken from the turbinates and the trachea, and the respiratory mucosa was examined by light and scanning electron microscopy. Dose-response curves to carbachol and isoproterenol were constructed using isolated strips of tracheal smooth muscle, with or without epithelium. In pigs exposed to ammonia, considerable mucosal injuries were observed in the turbinates but not in the trachea. The number of neutrophils in the epithelial layer and in the lamina propria, and epithelial hyperplasia were closely and significantly correlated with the concentrations of ammonia (r = 0.894, p < 0.001; r = 0.727, P < 0.001; and r = 0.818, p < 0.001, respectively). Except for the lamina propria, all these changes were significant (p < 0.05) at ammonia concentrations as low as 25 ppm. The percentage of the surface of the turbinate mucosa that was ciliated tended to decrease with increasing ammonia concentration (r = 0.439, p < 0.082). Ammonia induced smooth-muscle hyperresponsiveness to carbachol with a close linear correlation between individual values of the carbachol-induced maximal effect and the NH3 concentrations (r = 0.526, p < 0.003). While mechanical destruction of the epithelium induced an increase in Emax in the control group, no difference was observed between the intact and denuded strips from animals exposed to ammonia. The response to isoproterenol was not influenced by ammonia. It was concluded that quantitative histological analysis of the inflammatory infiltration and epithelial hyperplasia in the turbinates is a useful tool for quantifying the effects of atmospheric pollutants in pigs; a 6-day exposure to ammonia induces nasal irritation and functional disturbances of the tracheal smooth-muscle contractions at concentrations as low as 25 ppm.

Adrenergic beta-Agonists↗
PubMed1996

Ultrastructural changes in the duodenal mucosa induced by ingested histamine in patients with chronic urticaria.

Histamine in food may be responsible for some cases of food intolerance. We previously demonstrated disturbances in the metabolism of ingested histamine in patients with chronic urticaria (CU) and proposed that this could be related to increased intestinal permeability to histamine. The present study was undertaken to look for ultrastructural changes in the intestinal tract that might explain this abnormality. We examined duodenal biopsies from seven patients with CU before and after intraduodenal administration of histamine (120 mg). Five subjects had clinical symptoms (diarrhea, urticaria, headache, accelerated heart rate, and drop in blood pressure) within 1 h of duodenal histamine challenge (DHC). Ultrastructural changes, including edema of the interstitial tissue, enlargement of the basal intercellular spaces, slight congestion of the endothelial cells, and pericapillary edema, were observed in six subjects 45 min after DHC. In all the biopsies, the epithelium was normal, and the tight junctions were not modified by DHC. This morphologic study demonstrates that histamine can induce edema in the basal intercellular spaces of the duodenal mucosa and in the submucosa without evident change in the integrity of intercellular junctions. The most plausible route for histamine to have taken would appear to be an intracellular one.

Administration, Oral↗
PubMed1995

Effect of clofibrate on the peroxisomes of the intestine of the rat during foetal development.

The aim of the present work was to study the action of clofibrate, known as peroxisomal proliferator, on the intestinal peroxisomes in the foetus of treated pregnant females. The Novikoff technique (catalase activity detection) shows an increase in the number and size of intestinal peroxisomes in the treated females and in the foetus. Significant differences were observed between enterocyte peroxisomal enzymatic activities (catalase and PBE: peroxisomal bifunctional enzyme) in treated and control females on the one hand, and in the foetus of treated and control mothers on the other. The ultrastructural immunocytochemical study of the PPAR (peroxisome proliferator activated receptor) shows labelling of the enterocyte nucleus and mitochondria by the gold particles.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1994

Immunolocalization of albumin and transferrin in germ cells and Sertoli cells during rat gonadal morphogenesis and postnatal development of the testis.

The localization of albumin and transferrin was examined immunohistochemically in germ cells and Sertoli cells during rat gonadal morphogenesis and postnatal development of the testis. These proteins appeared as early as the 13th day of gestation in migrating primordial germ cells before Sertoli cell differentiation. In the fetal testis, strong immunoreactivity was only detected in the gonocytes. In the prepubertal testis, spermatogonia, primary spermatocytes, and some Sertoli cells accumulate albumin and transferrin. At puberty, different patterns of immunostaining of the germ cells were observed at the various stages of the cycle of the seminiferous epithelium. Diplotene spermatocytes at stage XIII, spermatocytes in division at stage XIV, and round spermatids at stages IV-VIII showed maximal staining. Labeling was evident in the cytoplasm of adult Sertoli cells. Albumin and transferrin staining patterns paralleled each other during ontogenesis.

Animals↗
PubMed1994

[Mesangial IgA deposits nephropathy].

Idiopathic IgA nephropathy of Berger's disease is characterized by prominent and diffuse IgA deposits in the mesangium. In many countries, it is the most common type of primary chronic glomerulonephritis. Typically, it is revealed by recurrent episodes of gross hematuria in association with ENT infection, but it can progress insidiously with microscopic hematuria and proteinuria. Serum IgA levels are increased in about 50% of cases. IgA nephropathy is not a minor condition: 20% of patients develop end-stage chronic renal failure 10 years after diagnosis and 50% after 20 years. IgA nephropathy can recur in a transplanted kidney suggesting that this disease is a systemic disorder although it has a remarkable tropism for the kidney. Even though many points remain to be elucidated, its pathogenesis appears to be linked to a genetic factor responsible for a lymphocyte dysfunction and an acquired environmental factor such as penetration of an antigen via the mucosa which may give rise to an excessive and inappropriate IgA immune response with the deposition of IgA in the mesangium and the development of progressive renal alterations. No treatment has been shown to be effective but tonsillectomy advised in case of a recurrent tonsillar focal infection is most often accompanied by a decrease in the incidence of gross hematuria. Corticosteroid therapy can be of benefit in cases involving a nephrotic syndrome associated with minimal glomerular lesions. In all cases, control of possible hypertension is of value in slowing the progression of this disease.

Adolescent↗
PubMed1994

[Electron microscopic studies of the action of erythromycin, doxycycline and ofloxacin on the growth cycle of Chlamydia trachomatis].

The aim of this work is to realise an ultra structural study of the action of antibiotics (doxycycline, erythromycin and ofloxacin) on the intracellular growth cycle of chlamydia. All assays were done on McCoy cells. Antibiotics were added to the culture medium two hours after inoculation with C. trachomatis. 24 and 48 hours, cells were removed and treated by standard procedure for transmission electron microscopy. No difference between control-cells and cells treated with doxycycline, erythromycin (0.015 mg/l) and ofloxacin (0.15 mg/l), was observed in the inclusions (number and size). However 48 hours, the quantity of elementary bodies (E.B.) was lower in treated culture. The organisms were not morphologically different from those seen in untreated culture. At higher concentrations of doxycycline and erythromycin (0.03 mg/l - 0.06 mg/l), the inclusions were smaller. Reticulate bodies (RB) were each in separate inclusion indicating that no fission has taken place. At 48 hours, no infectious forms (EB) were observed. Small or large RBs appeared with an apparent normal cytoplasmic membrane within an inflated cell wall. With ofloxacin (0.3 - 0.6 mg/l), inclusions contained enlarged and sometimes empty bacterial cells. Doxycycline and erythromycin (0.03 mg/l) inhibit the division of RBs and there maturation to EBs Ofloxacin (0.3 mg/l) induces the production of large abnormal forms which may not be able to revert towards viable bacteria.

Cell Division↗
PubMed1993

Tumour necrosis factor alpha and interleukin 2 in normal and infected human seminal fluid.

The presence of cytokines such as the tumour necrosis factor alpha (TNF alpha) and interleukin 2 (IL2) in human spermatozoa is still to be defined. The aim of this study was to measure the concentration of both soluble factors in seminal fluid. Data from normal semen samples (n = 24) confirmed the presence of IL2 (258 +/- 84 fmol/ml corresponding to 953 +/- 369 fmol/total volume of ejaculate) and TNF alpha (62.2 +/- 16.4 fmol/ml corresponding to 231.3 +/- 86 fmol/total volume of ejaculate). A significant positive correlation (r = 0.59; P < 0.01) was observed between the TNF alpha and the IL2 concentrations. The concentrations of these cytokines were not related to sperm parameters. In contrast, IL2 concentrations (196.9 +/- 60.4 fmol/ml; 686.2 +/- 236.7 fmol/total volume of ejaculate) evaluated in 16 seminal fluids with identified bacterial agents were lower than in the control group, whereas TNF alpha concentrations (68.6 +/- 12.3 fmol/ml; 241.3 +/- 78.9 fmol/total volume of ejaculate) were not significantly different from the controls. Further studies are needed to determine the potential role of these cytokines in the physiology of semen and their usefulness as indicators of reproductive pathology.

Bacteria↗
PubMed1993

[Interleukin-2 and human seminal fluid].

Involvement of the cytokines in male infertility were considered from in vitro studies, however the nature and the role of the mediator susceptible of arising in vivo is not completely elucidated. The purpose of this study is to measure the concentrations of interleukin-2 (IL-2) in normal and pathologic seminal fluid and to analyse their relationship with semen parameters. Our results demonstrate the presence of IL-2 in seminal fluid. Comparatively to normal seminal fluid, significant lower IL-2 concentrations were observed in infected semen samples or with sperm antibodies. No correlation was found between the cytokines values and the sperm parameters.

Autoimmune Diseases↗
PubMed1992

Intrinsic factor receptor during fetal development of the human intestine.

Intrinsic factor receptor activity was observed in mucosal homogenates from whole small intestine and colon of 10-19-week fetuses, whereas it was only detected in the distal part of the small intestine of a 25-week fetus. The receptor-intrinsic factor-cobalamin complex was eluted into the void-volume position when ileum mucosal extract was assayed for receptor activity by gel filtration after incubation with either fetal gastric extract or human gastric juice. The intrinsic-factor-binding capacity of intestinal mucosal extracts ranged from 2.6 to 30.5 fmol/mg and was correlated with the gestational age of six fetuses. The dissociation constant of the receptor for the intrinsic factor-cobalamin complex was estimated at 0.24-0.36 nM at pH 7.4. In conclusion, intrinsic-factor-receptor activity was detected in the whole intestine in 10-19-week fetuses, whereas it was only present in the distal ileum at the end of fetal development.

Chromatography, Gel↗
PubMed1992

Immunolocalization of high molecular weight kininogen (HKg) and T kininogen (TKg) in the rat hypothalamus.

Specific HKg immunostaining detected with antiserum against the light chain (LC) of HKg was restricted to SRIF neurons of the hypothalamic periventricular area projecting to median eminence (ME). Heavy chain (HC) immunoreactivity related to HKg and/or low molecular weight kininogen (LKg) was found in some other hypothalamic territories. Specific TKg was mainly associated with vasopressin in neurons of suprachiasmatic (SCN), supraoptic (SON) and paraventricular (PVN) nuclei. By direct RIA, hypothalamus was found to contain the highest level of TKg (10ng/mg protein) and after trypsin hydrolysis and HPLC separation of kinins, 10.3 pg BK and 7.3 pg T-kinin/mg protein.

Animals↗
PubMed1992

The plasma membrane of epididymal epithelial cells has a specific receptor which binds to androgen-binding protein and sex steroid-binding protein.

The binding of [3H] delta 6-testosterone photoaffinity-labelled rat androgen-binding protein (rABP) has been studied in an enriched fraction of plasma membranes of epithelial epididymal cells in immature (15 days) and adult rats (40 days). The binding was maximal in less than 30 min and more rapid at 4 degrees C than at 34 degrees C. It was calcium and pH dependent. Scatchard plots of the binding data gave curvilinear plots with two types of binding sites corresponding to a K(ass1) of 18.2 nM-1 and K(ass2) of 1.6 nM-1 (2.2 x 10(11) sites/mg protein and 5.4 x 10(11) sites/mg protein, respectively). In adult rats, only one type of binding site was found, with a K(ass) of 3.7 nM-1 (4.5 x 10(11) sites/mg protein). The number of receptors was 5-fold lower in the cauda than in the caput of the epididymis. The pretreatment of the isolated intact cells with streptozotocin induced a 45% reduction of the binding. Only unlabelled rABP and hSBP (human sex steroid-binding protein) but not other proteins (lactotransferrin, serotransferrin, asialofetuine, fetuine and bovine serum albumin) competed with the labelled ligand to bind plasma membranes. The membrane fraction was solubilized by triton X-100. Its incubation with labelled rABP and hSBP provoked the elution of the tracer as an aggregate into the void volume fraction of superose 6B mini-gel filtration columns. Structural homology between hSBP and rABP could be responsible for the common behaviour of the steroid-carrier molecules for the ABP receptor of rat epididymal epithelial cells.

Age Factors↗
PubMed1992

[DIfferentiation of enthesis and the synovial membrane in the rat].

The development of the knee joint in Wistar rats was observed from the 14th fetal day to the 40th postnatal day by light microscopy, transmission electron microscopy and scanning electron microscopy. The differentiation of the capsular ligamentous and tendinous attachments, synovial cavity, and A and B cells were particularly compared. Capsular attachments appeared for the first time at the 15th day of fetal life. The formation of the cavity started at the 17th day of fetal life. The differentiation of A and B cells was observed by the 20th fetal day by T.E.M., and only by the 15th postnatal day by S.E.M.

Animals↗
PubMed1992

[Study of cells harvested in nasal secretions after lavage. Improvement of the cytologic technique and application to ORL and bronchial pathology].

The study of the cells found in the nasal lavage fluid is now a very used method. It has many advantages and it is better than the study of nasal smears obtained by nose blowing and/or swabbing. In this work, we have studied the nasal cytology of patients with a nasal or bronchial pathology. A count of inflammatory cells in a hemocytometer is performed in 301 noses then the percentage of various cell types (eosinophils, lymphocytes and neutrophils) is performed on a glass slide stained by May Grunwald Giemsa. The results are correlated with the literature. The patients with a known NARES have a mean nasal eosinophilia of 26.8%; in the allergic rhinitis, the eosinophilia is 41.4%; the patients with a Fernand Widal Syndrome or with a nasosinusal polyposis have respectively a eosinophil percentage of 24.2% and 18.8%.

Bronchial Diseases↗
PubMed1991

Immunocytochemical localization of albumin, transferrin, angiotensinogen and kininogens during the initial stages of the rat liver differentiation.

Rat albumin, transferrin, angiotensinogen, T kininogen (TKg) and high molecular weight kininogen (HKg) gene expression was examined immunocytochemically in embryonic and fetal livers. All these plasmatic proteins, angiotensinogen excepted, are detected as early as day 11 of gestation in intestine epithelial cells and embryonic hepatocytes. Angiotensinogen becomes expressible only at day 13 of gestation. During the early fetal period, the protein immunostaining increases strikingly in parallel with the hepatocyte differentiation. Albumin and transferrin are highly expressed comparatively to kininogens and angiotensinogen. For the first time, specific HKg is demonstrated in the rat liver.

Albumins↗