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H Gerard

Publications and source records attributed to H Gerard.

At least 19 recordsLinked to original sources
PubMed2006

Evidence of a high proportion of premature unbalanced separation of sister chromatids in the first polar bodies of women of advanced age.

BACKGROUND: Maternal ageing is the only aetiological factor unequivocally linked to aneuploidy. Two mechanisms seem to explain these abnormalities in oocytes: non-disjunction and premature unbalanced separation of sister chromatids (PSSC). Previous studies of unfertilized oocytes argue for a major role of PSSC in the aetiology of aneuploidy for women of advanced age, but in vitro ageing of the oocytes could influence the results. METHODS: Owing to the high prevalence of aneuploidy in women of advanced age, chromosomal screening of the first polar body just before ICSI was offered to women (from 38 years of age) included in an assisted reproduction programme. RESULTS: Among 141 oocytes from 29 women (mean age 40 years and 2 months), 43 (30.5%) were abnormal. Sixty-five abnormalities were found and PSSC was involved in 80% of cases. CONCLUSION: These results are in accordance with previous studies and confirm, in 'fresh' oocytes, the major role of PSSC in the aetiology of aneuploidy in women of advanced age.

Adult↗
PubMed2004

[Negative impact of cigarette smoking on male fertility: from spermatozoa to the offspring].

Cigarette smoking has negative effects on male fertility. Recent studies showed an active transfer of several components of cigarettes through the blood-testis barrier. The presence of these components in the seminal plasma may induce a degradation of sperm parameters and nuclear quality of spermatozoa, and compromise the chances of pregnancy. Moreover, smoking may have a negative impact on the smokers'offspring: poor quality embryos, development of childhood cancers. Oxidative stress-induced DNA damage seems to be one of the major causes of sperm quality alteration. Several methods are now available to analyze the degree of DNA fragmentation. In order to optimize the success rate of assisted reproduction technologies, the deleterious effects of smoking on male fertility and the necessity of cessation have to be explained in detail to these patients.

Blood-Testis Barrier↗
PubMed2003

Flow-induced enhancement of concentration fluctuations in polymer mixtures.

Many mixtures of high-molecular-weight polymers are partially miscible, separating into two co-existing phases in some ranges of temperature and concentration. Generally these binary blends exhibit lower critical solution temperature (LCST) behaviour, becoming phase separated as the temperature is raised. We have been undertaking a systematic study of the effect of simple shear flow on the miscibility limits of a number of high-molecular-weight binary polymer blends exhibiting lower critical-solution temperatures. Using a parallel-plate shear cell and light-scattering detection, we have observed large shifts in the cloud-point curves as blends are heated while shear is applied, and we have been able to show, using ancillary measurements of glass-transition temperatures on quenched samples, that these effects are the results of changes in the miscibility of the blends and not artefacts of the scattering techniques. Both shear-induced 'mixing' and 'demixing' have been observed-the latter in temperature ranges well below the quiescent cloud points. We have investigated the kinetics of the appearance of the two-phase structures, and this is very reminiscent of the spinodal decomposition processes observed in zero shear from these blends. Small-angle neutron scattering is very sensitive to the rather short wavelength concentration fluctuations (a few nanometres) in binary systems, both in the stable one-phase region and in the early stages of instability in the two-phase region. Small-angle neutron-scattering results on blends sheared and quenched at temperatures far below the spinodal temperature show the effects of the shear in modifying the blend's structure factors.

Light↗
PubMed2000

Use of PRINS for preconception screening of polar bodies for common aneuploidies.

It has been shown that preconceptional screening for oocyte aneuploidies could help increase the pregnancy rate after in vitro fertilization (IVF), particularly in cases of advanced maternal age. The FISH (fluorescent in situ hybridization) technique is usually used to examine the first polar body (I-PB) for oocyte screening and so avoid fertilizing and transferring embryos from aneuploid oocytes. We have tested the feasibility of using another technique, the primed in situ (PRINS) reaction for this purpose. PRINS is a rapid, inexpensive method of labelling chromosomes. Chromosomes were labelled by in situ annealing with chromosome-specific oligonucleotide primers, followed by primer extension with labelled nucleotides using Taq DNA polymerase. A total of 183 PRINS reactions were performed with primers for chromosomes 13, 16, 18, 21 or X on 63 I-PBs removed from oocytes that failed to become fertilized during IVF. Each I-PB underwent three successive double-labelling reactions and intense signals were obtained in less than 40 min. Our data suggest that PRINS may be a useful alternative or a complement to FISH for detecting the main aneuploidies in all oocytes obtained after follicular puncture.

Adult↗
PubMed1999

Chlamydia trachomatis nucleic acids can be found in the synovium of some asymptomatic subjects.

OBJECTIVE: The recent identification of antigens or nucleic acids of infectious agents in the joints of patients with reactive arthritis has raised questions about whether chlamydial or other infectious agent nucleic acids are also present in normal joints. We had the opportunity to study synovium from 30 asymptomatic volunteer subjects by use of polymerase chain reaction (PCR) for attempted identification of Chlamydia and other infectious agents. METHODS: All subjects had blind needle synovial biopsies with the Parker-Pearson needle. DNA was extracted and PCR performed using primers for Chlamydia trachomatis, Chlamydia pneumoniae, Borrelia burgdorferi, and pan bacterial 16S ribosomal RNA (rRNA). RESULTS: Two subjects were identified with nucleic acid for the 16S rRNA gene of C trachomatis. All other PCR reactions were negative except for the pan bacterial 16S rRNA in the C trachomatis-positive subjects. Both subjects, although symptom free, had some evidence of synovial reaction. CONCLUSION: C trachomatis appears to occasionally be disseminated to joints without producing overt disease.

Adult↗
PubMed1999

[Rapid prototyping and bone reconstruction].

The authors describe the main techniques for rapid prototyping used in the medical field, with particular emphasis on Laser stereolithography. They describe the basics of the technique as well as the procedures they currently use to construct anatomic specimens from scanned images. For more than 10 years, the targets of researchers in the field of bone reconstruction in craniofacial surgery have been: to design a system to acquire data directly from CT-scans, to optimize modelling, processing and materials, to verify the possibility of producing prefabricated prostheses with data from preoperative models (22 cases). The target of integrating this technique into therapeutic protocols has been reached. The current trend in research is to produce prostheses from biocompatible materials directly from CT scan data by Laser stereolithography.

Computer-Aided Design↗
PubMed1996

Influences of type of anaesthesia on cortisol, beta-endorphin and heart rate in pigs.

Two experiments were carried out using a total of 20 growing pigs of approximately 20 kg in order to investigate the effect of different types of anaesthesia (metomidate versus ketamine) on plasma levels of cortisol and beta-endorphin on the heart rate. The animals were housed individually within a zone of thermal neutrality. Feed and water were available ad libitum. After becoming accustomed to human contact (being approached and touched), a catheter was implanted in the jugular vein, exteriorized in the neck region. This operation was performed under halothane anaesthesia. After recovery, hourly blood samples were taken over a 27 hour period, and cortisol and beta-endorphin concentrations were measured in the sample plasma. After this reference period, half of the animals were anaesthetized with metomidate, the other half with ketamine, and blood samples were taken at regular intervals. During a second experiment the heart rate was monitored after being anaesthetized as described before. An influence of the type of anaesthesia was observed on the plasma concentration of cortisol, but no effect was observed with respect to the beta-endorphin concentration. A fivefold increase of cortisol concentration was observed after injection with ketamine, while a twofold increase was observed after injection with metomidate. This finding suggests a suppressive effect of metomidate on the plasma cortisol levels. A fivefold increase was also observed for the beta-endorphin concentration after injection with either ketamine or metomidate. The increase in the heart rate was related to the awakening activity, which was more difficult after the ketamine injection.

Anesthesia↗
PubMed1994

Spermatogenic cells do internalize Sertoli androgen-binding protein: a transmission electron microscopy autoradiographic study in the rat.

Specific binding sites for androgen-binding protein (ABP) have been demonstrated recently to be present on germ cells from the rat and on membrane-enriched fractions from rat germ cells. The present study was undertaken to test if such receptors could lead to the activation of a specific internalization pathway as in other cells. Isolated rat germ cells and in situ rat germ cells, maintained within the seminiferous epithelium with either an intact or a bypassed blood testis barrier, were exposed to culture medium containing 12,000 cpm/ml [3H] delta 6-testosterone (2.5 pg) photoaffinity-labeled ABP, purified from rat testis. The follow-up of labeled ABP/germ cell interactions was based on qualitative and quantitative transmission electron microscopy autohistoradiography. Attention was focused on adluminal germ cells from pachytene spermatocytes to mature spermatids, which are normally present above the Sertoli cell tight junctions. Our observations revealed the presence in rat germ cells of structures related to specific endocytosis, namely coated pits and vesicles which stained positively with anticlathrin antibodies. When exposed to the [3H] delta 6-testosterone-ABP complex, adluminal germ cells showed marked labeling of these endocytic organelles. Preincubation either with excess unlabeled ABP or pretreatment by EDTA reduced the labeling significantly. Once internalized, ABP was found to be confined to the endocytic and nuclear compartments. The nuclear labeling was high in primary spermatocytes and round spermatids but was absent in elongated spermatids with condensed chromatin, in which transcriptional activity had almost stopped. In contrast, at later steps of spermiogenesis, the cytoplasm became heavily labeled, especially in the postnuclear part of elongated spermatids and in residual bodies about to be phagocytozed by Sertoli cells. Experiments using ligated seminiferous tubules, with an intact blood-testis barrier, clearly showed that ABP was captured at the basal part of Sertoli cells, transported up to the adluminal compartment and delivered to germ cells which finally internalized the protein. Experiments using largely opened seminiferous tubules allowing ABP to bypass the blood-testis barrier led to a delay in adluminal germ cell labeling compared with that in isolated germ cells. In all experiments in which germ cells were incubated in teh presence of Sertoli cells, the labeling observed at the surface of the germ cell line, especially over coated pits, was mostly found facing thin Sertoli cell processes, suggesting the possible existence of a specific mechanism for the presentation of ABP by the Sertoli cells to adluminal germ cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Androgen-Binding Protein↗
PubMed1994

Transport of pigs different with respect to the halothane gene: stress assessment.

Two transport experiments were carried out with 18 pigs each. These pigs originated from three genetic lines (homozygous halothane-positive and -negative and heterozygotes). Half the pigs were unfed for 12 h before transport. All pigs were transported twice for 2 h. Before and after transport pigs were anesthetized to take blood samples from the jugular vein and biopsies from the biceps femoris. At the same time equipment to measure body temperature and heart rate were attached or detached. Plasma cortisol and beta-endorphin concentrations were measured as well as the glycogen concentration in the muscle sample. Line differences were detected with respect to body temperature (P < .04), heart rate (P < .05), and cortisol (P < .01). The withholding of feed influenced (P < .04) plasma beta-endorphin concentration. Body temperature (P < .02), heart rate (P < .001), cortisol (P < .01), and beta-endorphin (P < .001) were different before and after transport, whereas a training effect of the transport number was observed for heart rate (P < .07) and plasma beta-endorphin (P < .02). No interactions between treatments were observed. The relationship between cortisol and beta-endorphin suggests a nonconcomitant release of ACTH and beta-endorphin.

Animal Welfare↗
PubMed1993

Endocytosis of transcobalamin in male rabbit germ cells: electron microscope radioautography study.

The binding of 125I-iodinated transcobalamin to a suspension of isolated rabbit germ cells was studied by Scatchard plot. The number of binding sites was evaluated to about 1000 per cell, and its association constant (Kass) in order of 14.6 l/nmole. The distribution to structures related to endocytosis was determined by ultrastructural histomorphometric studies. Both coated and uncoated structures were present regardless of maturation stage. The number of coated vesicles was at its highest in the initial maturation steps, whereas the number of uncoated vesicles was highest in the final maturation steps. The endocytosis of 125I-iodinated transcobalamin by the suspension of germ cells was studied by electron microscope radioautography. The tracer was mostly detected over the plasma membrane, coated vesicles and multivesicular bodies of germ cells. The grains were observed mainly over spermatocytes and round spermatids; 31.6% and 32% of these cells, respectively, were labeled. In contrast the tracer was detected in only 8.11% of elongated spermatids. In conclusion, iodinated transcobalamin is internalized in rabbit germ cells by receptor-mediated endocytosis. This phenomenon was predominant in the early stages of germ cell maturation.

Animals↗
PubMed1992

[Drug-induced pulmonary diseases: diagnostic, therapeutic and prognostic aspects. Apropos of 10 personal case reports].

The authors report ten cases of drug induced lung diseases, complicated by respiratory failure of whom five were attributed to cytotoxic drugs and five to non cytotoxic drugs. The drug induced lung disease presented as acute respiratory distress syndrome in two cases, alveolar interstitial lung disease in three cases, purely interstitial in five cases. There was acute respiratory failure (ARF) in eight cases and chronic respiratory failure (CRF) in two cases. Among the five patients admitted for cytotoxic drug induced lung disease and ARF, four recovered and one died of diffuse destructive pulmonary fibrosis. Among the five patients having non cytotoxic drug induced lung disease, three were in ARF and recovered. The other two had CRF and died of diffuse pulmonary fibrosis. The diagnostic of drug induced lung disease was established in each case with the chronology of the clinical events, the exclusion of other possible causes of the lung disease and the evolution after removal of the incriminated drug. Broncho-alveolar lavage (BAL) had a major diagnostic value. It was contraindicated by respiratory failure in five cases. The predominant alveolar cell type was lymphocyte (four cases), eosinophil (three cases) and neutrophil (one case), BAL was realized with a provocation test and demonstrated the pathogenic role of cyclothiazide in one case. No specific information was given by histology. The prognosis did not seem to be linked to the severity of the initial clinical picture, or to the nature of the underlying neoplastic disorder, but to the degree and evolution of the pulmonary fibrosis.

Adrenal Cortex Hormones↗
PubMed1992

[Fibrosing pneumopathy induced by cyclothiazide. Apropos of a case].

A diffuse interstitial pulmonary fibrosis associated with an idiopathic hepatic cirrhosis occurred in a 79 years old man treated during five years with cyclothiazide and triamterene for a mild systemic hypertension. The outcome was fatal. A provocation test was positive with BAL lymphocytic reaction. Cyclothiazide induced fibrosis is likely.

Aged↗
PubMed1991

Endocytosis of human sex steroid-binding protein in monkey germ cells.

We investigate in this study the hypothesis of human sex steroid-binding protein hSBP internalization into germ cells in a primate model. Human SBP was purified from late-pregnancy serum and labeled either with colloidal gold particles (18 nm) or with [3H]delta 6-testosterone by photoaffinity treatment. The germ cells were isolated from sexually mature monkey testis or caput epididymis (Macaca fascicularis) by mechanical means and cell suspensions (4 x 10(6) per 100 microliters culture medium) were incubated in presence of hSBP-gold complex (60 ng/100 microliters) or hSBP-[3H]delta 6-testosterone complex (66 ng/100 microliters, 20,000 cpm) for 2, 5, 15, 45, and 60 min. The samples were processed for electron microscopy followed by autoradiographic treatment for the radiolabeled samples. Localization of the label occurred over the whole germ cell lineage whichever tracer was used. Spermatogonia, spermatocytes, spermatids, testicular and epididymal spermatozoa exhibited specific binding sites over the plasma membrane associated with clathrin-like coated pits and vesicles. At 34 degrees C, intracellular localization of the labeled ligand was found within coated vesicles, in early and late endosomes. In addition, in early spermatogenic cells, labeled ligand was detected in the nuclei and/or associated with the nuclear envelope whereas in late spermatids and residual bodies, the labeling was accumulated in multivesicular, prelysosomal structures. Quantitative analysis of the "labeled cells/total cells" ratio exhibited a negative correlation to the maturation steps, epididymal spermatozoa being the least labeled. The cellular distribution is similar with one or the other protein in the same spermatogenic cells. Unlabeled hSBP treatment prior to labeled hSBP reduced significantly the internalization. Lowering the temperature to 4 degrees C prevented endocytosis and enhanced membrane binding. EDTA pretreatment strongly decreased hSBP internalization and modified the early endocytic steps, namely, the pinching off of the coated vesicles. It is concluded that monkey germ cells are able to internalize the human sex steroid-binding protein through specific endocytic organelles. This endocytosis leads to the labeling of the nuclei in the early spermatogenic cells and of the multivesicular bodies in the late germ cells. This strongly suggests that steroid-binding proteins may be required for spermatogenesis in acting at the germ cell lineage level either by themselves or by serving as steroid transmembrane carriers.

Animals↗
PubMed1991

Evidence that androgen-binding protein endocytosis in vitro is receptor mediated in principal cells of the rat epididymis.

We have studied the binding of [125I-iodo]androgen-binding protein (ABP) and of [3H]delta 6-testosterone photoaffinity-labelled ABP to receptors in the plasma membrane of rat epididymal cells in three ways: ABP binding to a Triton X-100-solubilized membrane extract, ABP binding to isolated epithelial cells in suspension and autoradiography of segments of dissected epididymides after in-vitro intraluminal injection of labelled ABP. The binding of iodinated ABP to the receptor was similar to that of photoaffinity-labelled ABP in gel filtration. The ABP-receptor complex was eluted from Superose 6 gels as an aggregate, with a molecular mass of 2000 kDa. It was separated into two peaks by sucrose gradient ultracentrifugation, with respective sedimentation coefficients of 18.4 and 9.0 s. The activity of the receptor (ABP-binding capacity/mg protein) was tenfold higher in the caput than in the cauda. The binding of ABP to the receptor was pH dependent, being almost abolished at pH less than 4. The binding at 4 degrees C of photoaffinity-labelled ABP to epithelial cells corresponded to two types of binding sites. The numbers of high-affinity and low-affinity sites per cell were 1600 and 7700 respectively; the association constants of these sites were 67.9 and 2.8 litres/nM respectively. The binding was decreased by treatment of the cells with trypsin or incubation in the presence of EDTA. The binding in vitro of labelled ABP to the epididymis epithelium reached a maximum after about 20 min at 4 degrees C. In the autoradiographic study the tracer was found to be closely associated with coated pits, coated vesicles, endosomes and pale multivesicular bodies. Treatment of rats with cycloheximide significantly reduced the uptake of the tracer. Perfusion in vitro of epididymides with chloroquine produced a fourfold increase of the tracer in endosomes and multivesicular bodies.

Androgen-Binding Protein↗
PubMed1990

Simultaneous anaphylaxis to thiopentone and a neuromuscular blocker: a study of two cases.

Two women experienced anaphylactoid reactions after induction of general anaesthesia. Prick tests, intradermal tests (IDT), human basophil degranulation tests (HBDT) and a quaternary ammonium sepharose radioimmunoassay were undertaken several weeks later and repeated together with a leucocyte histamine release (LHR) test after 4 months. Anaphylaxis to suxamethonium was documented by four tests in patient 1 and to pancuronium by four tests in patient 2. Anaphylaxis to thiopentone was shown with IDT, HBDT and LHR in both women. It was concluded that simultaneous anaphylaxis to thiopentone and a neuromuscular blocker had occurred in these patients.

Adult↗
PubMed1990

Internalization of human sex steroid-binding protein in the monkey epididymis.

Human sex steroid-binding protein (hSBP) has been purified from late-pregnancy serum and labelled either by iodination (125I) or by photoaffinity with [3H]delta 6-testosterone. Using a micromanipulator, each labelled protein was separately injected into the lumen of epididymal tubules isolated from the head epididymis of the cynomologus monkey (Macaca fascicularis). Tubules were sampled from 3 to 90 min after the injection and processed for electron microscope autoradiography. Localization of the label occurred over the epididymal epithelium whichever tracer was used. The labelling was not randomly distributed over the different cell types constituting the epithelium, since only the 'principal cells' exhibited a silver grain count significantly greater than the background count. In these cells, labelled protein was found over endocytic organelles (coated structures, endosomes, multivesicular bodies and the trans Golgi network) and nuclei (including the nuclear envelope). Quantitative analysis demonstrated the same pattern of cellular and subcellular distribution for each tracer. Pretreatment with excess unlabelled protein significantly reduced the uptake of radioactivity by the principal cells, demonstrating the specificity of this phenomenon. This is the first study to show direct histological evidence for the internalization of hSBP in the primate epididymis, consistent with earlier immunohistochemical or biochemical localization of this protein. It is concluded that head epididymal cells are able to take up labelled hSBP across their apical membrane. The mechanism of internalization seems to involve endocytosis by the principal cells and leads to labelling of the nuclear compartment. This is strikingly similar to the pattern of uptake of rat androgen-binding protein (rABP) by rat epididymal cells previously demonstrated by our group. To what extent the chemical and structural homology between hSBP and rABP can be held responsible for the common cytophysiological behaviour of these sex steroid-binding proteins remains to be determined.

Affinity Labels↗
PubMed1989

[Probable allergy to polyvidon, responsible for a reaction to iodinated contrast medium: a case of asthma after hysterosalpingography].

A case of asthma induced by a iodinated medium (ICM) is reported. The ordinary ICM for urography were well tolerated. The suspected drug included polyvidon (PVP). Skin test, human basophil degranulation tests and leukocyte histamine release are negative for meglumine ioxitalamate, and positive for PVP. PVP is a macromolecule, used in different drugs, and as a clarifying agent of alcohols. An IgE-dependent allergy to PVP is postulated.

Asthma↗