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Biomedical subjects

P Guérin

Publications and source records attributed to P Guérin.

At least 19 recordsLinked to original sources
PubMed2006

[Bi-directional ventricular tachycardia and pheochromocytoma: a case report].

We present the case of a 48 year old woman who was admitted to our university hospital in cardiogenic shock with bi-directional ventricular tachycardia degenerating into polymorphic venricular tachycardia which resolved spontaneously. Investigation revealed healthy coronary arteries but severe left ventricular dysfunction due to akinesia involving the entire base. There was a rapid improvement within several days. The diagnosis of bilateral phaeochromocytoma was made on the biochemistry and CT scan of the adrenals.

Adrenal Gland Neoplasms↗
PubMed2005

[Impact of sperm DNA fragmentation on ART outcome].

We have used the sperm chromatin structure assay (SCSA) test in order to determine if correlations can be found between sperm DNA fragmentation and spermogram parameters. Only necrospermia and DNA fragmentation index are strongly correlated (P<0.0001). Neither fertilization rates for ICSI and IVF, nor blastocyst formation rates are impaired by a high DFI. However when the critical DFI>30% is reached, the chances of having ongoing pregnancies after blastocyst transfer are reduced by three. Treatments with antioxidants are of limited efficacy even though we obtained 2 deliveries after DFI treatments with such treatments. New strategies in order to improve the pregnancy rates for these peculiar cases of reduced fertility are discussed.

Adult↗
PubMed2005

[Follicular morphology after ovarian cortex cryopreservation in the rabbit doe(Oryctolagus cuniculus)].

OBJECTIVE: To compare the effects of two cryoprotective agents (DMSO and 1,2-PROH) used at two concentrations (1,5 and 2 M) on the morphology of small ovarian cortex follicles in doe. MATERIALS AND METHODS: Ovarian cortexes (n=40) were frozen in TCM199+10% FCS medium added to 1.5 or 2 M of DMSO or 1,2-PROH. Two controls were realized (fresh and frozen without cryoprotectant). The equilibration in cryoprotective solutions before freezing, and the elimination of the cryoprotective agents after thawing, was performed step by step. The effects induced by cryopreservation were evaluated by histological examination. RESULTS: Fresh ovarian tissue showed 68.6% of intact follicles. After freezing, only 1.5 M of 1,2-PROH preserved 48.0% of normal follicles, with no significant difference compared to the fresh control. The proportion of follicles without morphological defect observed after cryopreservation with DMSO was significantly reduced (respectively 28.8 and 34.8% for 1,5 and 2 M of DMSO). DISCUSSION AND CONCLUSIONS: Our results suggest that 1,2-PROH is a more effective cryoprotectant than DMSO, for the cryopreservation of doe ovarian cortex. These results differ from those that were obtained for other species, credibly because of a higher fragility of the ovarian tissue of the doe. Nevertheless, this species is an interesting animal model which allows rapid results after cryopreserved ovarian tissue graft.

Animals↗
PubMed2005

[Arterial rigidity of patients operated successfully for coarctation of the aorta without residual hypertension].

In patients successfully operated for coarctation of the aorta, the prevalence of hypertension is higher than that observed in the general population although the exact mechanism is not known. The hypothesis of increased arterial rigidity despite satisfactory correction of the coarctation has been proposed. The authors undertook 24 hour ambulatory blood pressure monitoring coupled with measurement of the QKD interval (pulse wave velocity) in order to evaluate the rigidity of the large arteries. These results were compared with those obtained in control patients paired with respect to gender, age, height and weight. Twenty-six patients with an average age of 14.5 +/- 2.9 years were included (age at time of surgery 6.3 +/- 3.7 years). The statistical data confirmed a higher systolic blood pressure (p<0.05) in the operated patients compared with controls. The results confirm the hypothesis of increased residual arterial rigidity in children operated for coarctation of the aorta which could predispose to secondary hypertension, especially on effort. In the long term, this could be an unquestionable cardiovascular risk factor explaining the increased cardiovascular morbid-mortality compared with the general population.

Adolescent↗
PubMed2005

[Septal alcoholisation of hypertrophic obstructive cardiomyopathy in childhood].

The authors report a case of septal alcoholisation in a 6 year old child with hypertrophic obstructive cardiomyopathy responsible for congestive cardiac failure despite optimal betablocker therapy. The indication was retained in a context of mucoviscidosis complicated by multiresistant bacterial infection. At catheterisation, the dominant septal artery was identified and an alcoholisation was performed by the classic technique described in adults. The immediate result was satisfactory with regression of the signs of cardiac failure and reduction of 70 mmHg of the maximal instantaneous pressure gradient (from 160 to 90 mmHg). However, 10 months later, the signs of right heart failure reappeared with a partial increase in the maximal instantaneous pressure gradient (100 mmHg) leading to surgical myectomy while the patient's condition had considerably improved from the pulmonary point of view. Septal alcoholisation would appear to be a therapeutic alternative in children especially in cases with a temporary or permanent contraindication to conventional surgery.

Cardiac Catheterization↗
PubMed2004

Effect of injecting collagenase into the uterine artery during a caesarean section on the placental separation of cows induced to calve with dexamethasone.

A caesarean section was performed on 30 cows before normal term and 16 to 20 hours after the induction of parturition with dexamethasone. During the surgical procedure, 20,000 U of bacterial collagenase was injected into the uterine artery of 15 of the cows. The average periods of retention of the fetal membranes were 40 hours in the treated cows and 114 hours in the control cows (P<0.001). At 36 hours after the surgery six of the treated cows (40 per cent) but all 15 of the control cows had retained fetal membranes. The collagenase-treated cows showed no abnormal clinical signs during the 10 days after the operation.

Animals↗
PubMed2004

Neointimal hyperplasia after stenting in a human mammary artery organ culture.

Although the use of stents has limited the incidence of restenosis, in-stent restenosis remains an important problem. In-stent restenosis is the result of a healing process that induced neointimal hyperplasia through mechanisms that are still not understood. The aim of this study was to analyze the histological consequences of the healing process following stent implantation. Internal mammary arteries from atheroslerotic patients undergoing coronary artery bypass surgery were stented and maintained in culture for 0-28 days. Stent implantation after predilatation induced an extensive loss of endothelial cells whereas direct stenting preserved endothelium between the struts. Morphometric analysis shows that stent placement induced neointimal thickening. Smooth muscle alpha-actin labeling indicates that neo-intimal formation was mainly due to proliferation and migration of smooth muscle cells. Smooth muscle cell proliferation, assessed by MIB-1 staining, was maximal at day 14 after stent insertion. Human mammary artery organ culture thus provides valuable information on histological consequences of stent implantation with or without predilatation regarding endothelial cell disappearance and neointimal hyperplasia. These data also demonstrate that neointimal thickening induced by stent implantation comprises an intrinsic component resulting from the vessel wall response to stent insertion and suggest that blood factors could play an amplifying but not necessary role.

Cell Division↗
PubMed2002

[Endocarditis and congenital heart disease in the adult].

The prevalence of congenital cardiopathy is approximately 8% of live births, and 80 to 85% of patients reach adulthood thanks to the progress in the management of even complex malformations. Congenital cardiopathies represent 10 to 18% of adulthood cardiopathies complicated by infectious endocarditis, and in the specialist units for adolescent and adult congenital cardiac patients, 5% of admissions are provoked by endocarditis. The majority of malformations have a risk of infected graft, but patients who have a complex cyanogenic cardiopathy or an operated cardiopathy requiring insertion of prosthetic material, and those who have already had previous episodes of endocarditis are at a very high risk. Longitudinal studies show evolution of the responsible microbes, with an increase of the HACEK group; nevertheless, the streptococci and staphylococci remain uppermost. Diagnosis relies on the classic Duke University criteria but Doppler echocardiography is sometimes difficult to interpret in complex malformations or extra-cardiac sites of infection, and in 6 to 11% of cases the microbe is not identified. Infectious endocarditis remains a particularly serious complication: 50% of patients have aggravation of their cardiopathy and 20 to 30% require surgery; however the mortality has fallen by 20% to a little less than 5% in the most recent series. It is vital that patient education should be pursued even if, in certain circumstances, prophylaxis is not always either possible or effective....

Diagnosis, Differential↗
PubMed2001

Taurine and hypotaurine in spermatozoa and epididymal fluid of cats.

Taurine and hypotaurine have been found in spermatozoa and seminal plasma of numerous species and are known to have beneficial effects on sperm characteristics in mammals. Taurine is considered an essential dietary constituent in cats. Dietary deficiency has been associated with a range of serious clinical disorders. Quantification of taurine and hypotaurine in the genital tracts of male cats has not been reported. In this study, the concentrations of taurine and its precursors were measured in serum, spermatozoa, epididymal fluid and seminal plasma from cats. The concentrations of taurine measured in serum samples confirmed that the cats were not deficient in taurine. Significant amounts of taurine and hypotaurine were found in spermatozoa, seminal plasma and epididymal flushing fluid. Hypotaurine was not detected in serum samples. These results indicate that hypotaurine may be synthesized in cat testes or epididymides. Cysteamine was not detected in any of the samples.

Animals↗
PubMed2000

Mammalian oviduct and protection against free oxygen radicals: expression of genes encoding antioxidant enzymes in human and mouse.

Genetic expression of five antioxidant enzymes involved in mechanisms protecting embryos against reactive oxygen species (ROS) was studied in human and mouse oviducts. The presence of transcripts encoding for gamma-glutamylcysteine synthetase (GCS), glutathione peroxidase (GPX), Cu-Zn-superoxide dismutase (Cu-Zn-SOD), Mn-superoxide dismutase (Mn-SOD) and catalase was analysed by use of the reverse transcription-polymerase chain reaction (RT-PCR). Different expression profiles of transcripts encoding for these enzymes were observed between human and mouse oviducts. In the mouse, all transcripts encoding for the enzymes tested were present in oviduct. In human, only transcripts encoding for GPX, Cu-Zn-SOD and catalase were also detected in oviduct. However, GCS and Mn-SOD transcripts were never observed in human oviduct. Cu-Zn-SOD transcripts are relatively highly expressed whatever species. These results suggest that different gene expression patterns of these antioxidant enzymes between human and mouse may reflect the variations in the ability of embryos to develop in vivo and in vitro. However, hormone related-expression of the missing transcripts in human cannot be ruled out.

Animals↗
PubMed2000

[Osler endocarditis of a ventricular septal defect in a 21-month old child].

The authors report a case of streptococcus mitis endocarditis of a ventricular septal defect in a 21 months old girl admitted for necrotic purpura of the lower limbs and a history of general ill health and pyrexia for two months. The severity of this case of endocarditis was illustrated by the importance of the vasculitis, the biological signs of infection (disseminated intravascular coagulation), and the size of the vegetation. The vegetation extended from the tricuspid valve as far as the pulmonary orifice which was partially obstructed, causing signs of right ventricular failure. The portal of entry was not found. Surgical ablation of the vegetation with tricuspid valvuloplasty was necessary after 48 hours of antibiotherapy. The outcome after one year's follow-up is good. The diagnosis of bacterial endocarditis must be considered even in very young children, especially those with congenital heart disease, and, in particular, ventricular septal defect.

Echocardiography↗
PubMed1999

In vitro capacitation of dog spermatozoa as assessed by chlortetracycline staining.

We developed an assay for detecting capacitation and acrosome status in dog spermatozoa using chlortetracycline (CTC) as a fluorescent probe. Sperm cells were stained after incubation in modified canine capacitation medium (mCCM). Calcium ionophore A23187 permitted the induction of acrosomal exocytosis of capacitated sperm cells. Spermac staining and transmission electron microscopy were used as control tests to detect acrosome-reacted spermatozoa. Three different patterns of CTC distribution in the spermatozoa were found. These patterns were similar to those observed in other mammalian species. The CTC test was used to monitor the time course of the capacitation process in dogs. It was found that the kinetics of capacitation in canine sperm cells are similar to those observed in other mammals.

Acrosome Reaction↗
PubMed1999

Expression of genes encoding antioxidant enzymes in human and mouse oocytes during the final stages of maturation.

The mRNA expression of five enzymes: catalase, Cu-Zn-superoxide dismutase (Cu-Zn-SOD), Mn-superoxide dismutase (Mn-SOD), glutathione peroxidase (GPX), and gamma-glutamylcysteine synthetase (GCS) each involved in protection against free radicals was studied in human and mouse oocytes. In the mouse, oocytes were collected at different stages of maturation in order to determine the storage of these transcripts. For the human, germinal vesicle (GV) oocytes harvested during intracytoplasmic sperm injection (ICSI) procedures and failed fertilized metaphase II (MII) oocytes were analysed. Human and mouse were compared in order to determine whether the differential developmental capacity of mouse and human preimplantation embryos in culture could be explained by the variations in the patterns of expression for these enzymes. mRNA expression for these enzymes was examined using reverse transcription-polymerase chain reaction (RT-PCR). In the mouse, all transcripts (except for catalase) were detected, whatever the maturation stage. No qualitative differences were detected between GV and MII oocytes. In human, all the enzymes (except for catalase) were expressed in MII oocytes and Cu-Zn-SOD was particularly highly expressed. Transcripts corresponding to GPX and Mn-SOD were not detected at GV stage but only at MII stage, suggesting that storage could occur between GV and MII stages. However, using 3' end-specific primers for GPX and Mn-SOD, instead of the oligo(dT)(12-18) primer, for the reverse transcription reaction, the transcripts for these antioxidants enzymes have been detected in human oocytes at the GV stage. This suggests the presence of maturation-specific polyadenylation of these transcripts. These enzymes can be considered as markers of cytoplasmic maturation.

Animals↗
PubMed1998

Precursors of taurine in female genital tract: effects on developmental capacity of bovine embryo produced in vitro.

Two precursors of taurine have been studied: cysteamine and hypotaurine. Cysteamine has been quantified in genital secretions and found in follicular fluids of all species tested. On the contrary cysteamine was not detected (or traces) in tubal fluids of the same species. Addition of 50, 100 or 250 microM of cysteamine to the maturation medium used in the culturing of bovine oocytes did not improve the cleavage rate nor the embryo's developmental potential in vitro. Furthermore, at 250 microM, cysteamine seems to be toxic to the embryo. Addition of 0.5-1 mM hypotaurine to the bovine embryo culture medium improved significantly blastocyst production and quality. The respective roles of these 2 taurine precursors on maturation and embryo development are discussed.

Animals↗
PubMed1998

[Study of the cardiorespiratory response and chronotropic function after correction of tetralogy of Fallot. Important role of residual pulmonary regurgitation].

Effort tolerance is reduced after correction of Tetralogy of Fallot. This prospective study investigated the cardiorespiratory response and the chronotropic function (mean follow-up 11.1 years) of 70 patients (43 boys and 27 girls) with an average age of 14.9 +/- 7.2 years (group 1) compared with 65 normal, sedentary subjects paired red for age and gender (group 2). All underwent exercise testing (Bruce protocol) with measurement of respiratory gases. Quantification of pulmonary regurgitation was performed by Doppler echocardiography. The chronotropic response to exercise was assessed by calculating the mean of slopes established by chronotropic metabolic relationship of Wilkoff. The cardiorespiratory response to exercise was abnormal in group 1: the duration of exercise (11.3 vs 13.6 min; p = 0.005), peak VO2 (35.5 vs 46 ml/min/kg; p < 0.001) and anareobic threshold (8.3 vs 9.2 min; p = 0.001) were decreased. Maximal heart rate (172 vs 190bpm; p < 0.001) and the mean of the metabolic-chronotropic slopes (0.68 vs 0.83; p < 0.001) were decreased in the patient group, showing abnormal chronotropic response to exercise. The latter seemed to be related to the severity of pulmonary regurgitation. The duration of exercise (10.6 vs 11.5 min; p = 0.001), peak VO2 (33 vs 37 ml/min/kg; p < 0.001), maximal heart rate (161 vs 177 bpm; p = 0.002) and the mean of the slopes of the metabolic-chronotropic relationship (0.59 vs 0.72; p < 0.001) were decreased in patients with moderate to severe pulmonary regurgitation. This study shows that significant pulmonary regurgitation is responsible for a poor cardiorespiratory response to exercise and for an abnormal chronotropic response which seems to be multifactorial but probably related to an adaptation favouring left ventricular filling during exercise.

Adolescent↗
PubMed1998

[Double stenosing valve disease after mediastinal radiotherapy: a case report of a 31 year-old man].

Cardiac complications of radiotherapy for cancer, especially lymphoma and breast cancer, are well documented. The three tunics of the heart can be affected. However, valvular disease is rare and, when present, is usually regurgitant. Stenosis is very rare. The authors report the case of a 31 year old man who developed double mitro-aortic valvular stenosis 20 years after mediastinal radiotherapy associated with aortic regurgitation, right coronary stenosis and inflammatory epicardo-pericarditis with effusion. Surgery was undertaken and associated double aortic and mitral valve replacement and right coronary by pass grafting.

Adult↗
PubMed1997

Bioclinical profiles of autism and other developmental disorders using a multivariate statistical approach.

To study the relationships between clinical and biological data that are necessary for physiopathological analysis in the field of developmental disorders, we developed a quantified grouping system, based on four developmental assessment parameters. Parallel with this clinical research, we developed electrophysiological procedures adapted to the pathology of autism. In this paper, we report the utilization of an original multivariate descriptive statistical approach (correspondence analysis followed by cluster analysis) that allowed us to identify different bioclinical profiles using these clinical and electrophysiological data conjointly. These profiles are believed to be evidence for different underlying cerebral dysfunctions. This procedure proved effective in identifying two main bioclinical dimensions in a population of 145 developmentally disordered children. These dimensions reflect the association of intellectual impairment and centroparietal electrophysiological reactivity on the one hand, and autistic behavior and temporal electrophysiological reactivity on the other. This study, performed on a large population of children using objective methods of data analysis, provides validation of numerous multidisciplinary studies of autism and other developmental disorders carried out on small samples of children.

Autistic Disorder↗