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S Belisle

Publications and source records attributed to S Belisle.

At least 19 recordsLinked to original sources
PubMed2006

Critical oxygen delivery during cardiopulmonary bypass in dogs: pulsatile vs. non-pulsatile blood flow.

BACKGROUND AND OBJECTIVE: To determine the minimal oxygen delivery and pump flow that can maintain systemic oxygen uptake during normothermic (37 degrees C) pulsatile and non-pulsatile cardiopulmonary bypass in dogs. METHODS: Eighteen anaesthetized dogs were randomly assigned to receive either non-pulsatile (Group C; n = 9) or pulsatile bypass flow (Group P; n = 9). Oxygen delivery was reduced by a progressive decrease in pump flow, while arterial oxygen content was maintained constant. In each animal, critical oxygen delivery was determined from plots of oxygen uptake vs. oxygen delivery and from plots of blood lactate vs. oxygen delivery using a least sum of squares technique. Critical pump flow was determined from plots of lactate vs. pump flow. RESULTS: At the critical point, oxygen delivery obtained from oxygen uptake was 7.7 +/- 1.1 mL min(-1) kg(-1) in Group C and 6.8 +/- 1.8 mL min(-1) kg(-1) in Group P (n.s.). These values were similar to those obtained from lactate measurements (Group C: 7.8 +/- 1.6 mL min(-1) kg(-1); Group P: 7.6 +/- 2.0 mL min(-1) kg(-1)). Critical pump flows determined from lactate measurements were 55.6 +/- 13.8 mL min(-1) kg(-1) in Group C and 60.8 +/- 13.9 mL min(-1) kg(-1) in Group P (n.s.). CONCLUSIONS: Oxygen delivery values greater than 7-8 mL min(-1) kg(-1) were required to maintain oxygen uptake during normothermic cardiopulmonary bypass with either pulsatile or non-pulsatile blood flow. Elevation of blood lactate levels during bypass helps to identify inadequate tissue oxygen delivery related to insufficient pump flow.

Algorithms↗
PubMed1993

Low-dose aprotinin infusion is not clinically useful to reduce bleeding and transfusion of homologous blood products in high-risk cardiac surgical patients.

A high-dose regimen of aprotinin 5-6 million KIU is effective in reducing bleeding and the need for homologous blood products (HBP) associated with cardiopulmonary bypass (CPB). These high doses aim at achieving plasmin and plasma kallikrein concentrations which in vitro are inhibitory but, theoretically, smaller doses could suffice in vivo. Also, aprotinin is an expensive drug, so efficiency requires using the smallest effective dose. Therefore, the efficacy of prophylactic aprotinin 1 million KIU (the maximal dose approved currently) was evaluated in a patient population at high risk of bleeding and of being transfused. Forty-one patients undergoing reoperation or a complex surgical procedure were included in a prospective, randomized, placebo-controlled, double-blind study. Before skin incision, a bolus of 200,000 KIU aprotinin was administered in 20 min, followed by an infusion of 100,000 KIU.hr-1 over eight hours. Control patients received an equal volume of saline. Dryness of the operative field, chest drainage, transfusion of HBP, haemoglobin concentrations, and coagulation variables (including bleeding time) were compared. There were no differences between aprotinin and placebo-treated patients for all clinical and laboratory variables. The apparent ineffectiveness of aprotinin may be explained by the use of an insufficient dose, by a different protocol of administration (e.g., no bolus in CPB prime), or by the inability of aprotinin to decrease bleeding and transfusions any further. Also, the number of patients studied does not exclude the possibility of a Type II error.(ABSTRACT TRUNCATED AT 250 WORDS)

Aprotinin↗
PubMed1993

Inotropic support of the heart that fails to successfully wean from cardiopulmonary bypass: the Montreal Heart Institute experience.

The selection of an appropriate therapeutic regimen, especially in patients with preexisting cardiac dysfunction prior to surgery, is a crucial element for successful separation from cardiopulmonary bypass (CPB). At the present time there are no definitive studies to determine which treatment modality, or combination of treatments, is optimal in this patient population. A brief review of the literature is presented to answer the following questions: (1) Should inotropic support be administered in anticipation of failure to wean from CPB? and (2) Which inotrope or combination of drugs is best? There is no evidence at present that the prophylactic administration of inotropes to assist separation from CPB may result in damaging effects to the myocardium in humans. Inasmuch as tachycardia is avoided and coronary perfusion pressure is maintained within the normal range, prophylactic inotropes may be of benefit to patients with preexisting myocardial dysfunction during weaning from CPB by allowing a smoother separation and a shorter time on CPB. While no specific drug has been proven superior, the use of phosphodiesterase inhibitors as part of the regimen to provide inotropic support in these patients may exert a beneficial effect on myocardial ischemia and reperfusion injury. Prophylactic support of the circulation during separation from CPB, especially with phosphodiesterase inhibitors, may be indicated in this specific patient population as part of the strategy to ensure maximal preservation of myocardial function.

Adrenergic beta-Agonists↗
PubMed1992

Characterization of 3,5,3'-triiodothyronine receptors in primary cultures of hepatocytes and neurons from chick embryo.

We have detected the presence of nuclear 3,5,3'-triiodothyronine (T3) receptors in primary cultures of chick embryo hepatocytes and neurons. Hepatocytes were isolated from livers of embryos of 12, 16 and 19 days by treatment with 0.2% collagenase and hyaluronidase. They were plated at a density of 3-4 x 10(5)/35-mm petri dish in Ham's F-10 medium containing fetal calf serum, tryptose phosphate, and antibiotics. Cells were used for the binding assay at Day 3 of culture. Neurons from 8-day-old embryo brains were cultured in a serum-free medium at a density of 1.2 x 10(6) cells/35-mm petri dish and used for the binding assay after 7 days of culture. Biological activity of hepatocytes was determined by measuring insulin binding, inositol phosphate formation, and 5'-monodeiodinase activity. Neurons or glial cells in culture were identified by immunostaining with anti-neurofilaments and anti-glial fibrillary acidic protein antisera. Binding assay was performed with isolated nuclei and 0.4 M NaCl nuclear extracts. With the latter preparation, the Scatchard analysis showed, in both cells, a single, high-affinity, low-capacity T3 receptor. In the hepatocytes of 12-, 16-, and 19-day-old embryos association constants (Ka) were, respectively, 0.93 +/- 0.02, 0.74 +/- 0.03, and 0.56 +/- 0.04 nM-1, whereas the maximal binding capacities (MBC) were 2.26 +/- 0.2, 2.72 +/- 0.33, and 1.83 +/- 0.19 fmol/microgram DNA (mean +/- SE, n = 3). In neurons Ka was 1.25 +/- 0.53 nM-1 and MBC 0.59 +/- 0.14 fmol/microgram DNA (n = 3). The receptor had a sedimentation coefficient of 3.4 S, an estimated Mr of 59 kDa, and the following relative affinity for thyroid hormone analogues: TRIAC greater than L-T3 greater than L-T4. These data indicate that cultured hepatocytes and neurons of chick embryo contained T3 receptors with properties similar to those described in intact tissues from this and other species. Only the MBC of neurons was 50% lower than that observed in whole brain of embryo, but was comparable to values observed in cultured neurons from other species.

Animals↗
PubMed1991

Inwardly rectifying currents in human term placental cells.

Using the whole cell voltage clamp technique, inwardly rectifying currents were observed in most cells isolated from human term placentas. Reversal potentials, estimated by extrapolation, as well as those estimated by tail currents, were found to be between -80mV and -90mV. These potentials are close to the potassium equilibrium potential (theoretical value: -82 mV). In addition, the inwardly rectifying currents were blocked by 1 mM CsCl. The elevation of [K]e increased the current amplitudes. Furthermore, the holding currents were inwardly shifted when the holding potential was kept at -70mV. The extrapolated reversal potentials changed linearly on a semilogarithmic graph with a slope of 57 mV/decade of [K]e. This value is close to the theoretical calculation (58 mV/decade). Consequently, it is suggested from these studies, that inwardly rectifying currents observed in human term placental cells are carried mainly by potassium ions.

Cesium↗
PubMed1991

Are consumers of modern fertility treatments satisfied?

OBJECTIVE: To determine the extent of patients satisfaction with fertility treatments, its antecedents, and its correlates. DESIGN: This is a two-wave correlational panel study in which consumer satisfaction was assessed 6 and 12 months after admission to the clinic. PATIENTS: The sample consisted of 385 couples who consulted the fertility clinic of a large metropolitan hospital. MEASURES: After their admission, patients completed scales measuring psychosocial disturbances. These variables were reassessed 6 and 12 months later along with a consumer satisfaction questionnaire. RESULTS: Patients were generally satisfied with modern fertility treatments. Approximately 10% of the sample expressed dissatisfaction with received services. Analyses revealed that consumer satisfaction was significantly related to poor psychosocial functioning at intake and after 6 months. CONCLUSIONS: Our results suggest that consumers of fertility treatments are generally satisfied with the quality and quantity of service they received at the clinic. The more patients exhibited personal, marital, and social symptoms of distress when they were admitted to the clinic, the more they were likely to be later dissatisfied with fertility treatments.

Adaptation, Psychological↗
PubMed1990

Hypothalamic-pituitary axis during reproductive aging in mice.

We correlated the content of hypothalamic (HT) GnRH and pituitary (PT) GnRH receptor sites with PT and plasma gonadotropin levels throughout aging in C57BL/6J mice. Female mice of 4-6 months (young), 10-12 months (middle-age) or 15-18 months (old) of age were studied either intact or 15 days post-ovariectomy (OVX) with or without E2 therapy. In intact mice, HT GnRH content increased twofold during aging while GnRH receptor sites in PT remained unchanged. PT content of both FSH and LH gradually rose during aging while plasma concentration rose even more. OVX resulted in a significant decrease in both HT GnRH content and PT receptor sites and no age difference was observed. OVX also resulted in a significant increase in both PT content and plasma levels of gonadotropin in young and middle-age mice while old mice showed a blunted response. After E2 therapy for 7 days, HT GnRH content and PT GnRH receptor sites returned to normal levels in all age groups. By contrast, E2 therapy resulted in no change in PT content of FSH:LH in any age group. Whereas plasma FSH:LH levels returned to intact levels in young mice, they remained elevated to OVX levels in middle-age and old ones. Our results demonstrate an age related dichotomy in the PT production of FSH:LH unrelated to changes in either HT GnRH content or its PT receptor sites, thus suggesting cellular defects in post-receptor binding events within the pituitary.

Aging↗
PubMed1990

An islet-activating protein-sensitive G-protein is involved in dopamine inhibition of both angiotensin-stimulated inositol phosphate production and human placental lactogen release in human trophoblastic cells.

In isolated human trophoblastic cells, dopamine (DA) significantly inhibited the angiotensin-II (AII)-stimulated inositol phosphate (IP) accumulation by 44 +/- 8% (EC50, 0.5 +/- 0.2 microM) and human placental lactogen (hPL) release by 85 +/- 5% (EC50, 1.0 +/- 0.8 microM). These effects were blocked by sulpiride, a specific D2 antagonist. On the contrary, scherring 23390 (a specific D1 antagonist) and propranolol (a specific beta-adrenergic antagonist) were ineffective, suggesting that these DA effects are mediated through a DA receptor of the D2 subtype. The mechanism by which DA inhibited AII-stimulated inositol phosphate production implicates a GTP-binding protein sensitive to the islet-activating-protein (IAP), since DA's effects on IP accumulation and hPL release were blocked by this toxin. To further characterize this GTP-binding protein, particulate fractions of placental cells were incubated with [alpha-32P]NAD and IAP. Solubilized extracts were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two proteins of 40 and 41 kDa mol wt were specifically ADP ribosylated. They were probably involved in the DA inhibitory processes, since IAP treatment, known to suppress the effects of DA, also reduced the labeling of these two molecules by around 40%. The effects of AII and DA on hPL release appear to be insensitive to the external calcium concentration, since the results were not significantly different in normal (1.8 mM Ca2+) and low Ca2+ (10(-5) M Ca2+) concentrations. On the other hand, increasing the intracellular concentration of cAMP by adding forskolin did not modify the effect of DA on either IP accumulation or hPL release, suggesting that cAMP is not implicated in hPL release from freshly isolated human trophoblastic cells.

Adenosine Diphosphate↗
PubMed1989

Estradiol receptor-nuclear interactions in aging mouse uteri: the role of DNA and nuclear matrix.

We have studied the interactions of estradiol receptor (ER) with nuclear DNA or matrix (NM) in the uteri from young, middle-aged and old mice. Recombination studies using heat-activated ER and nuclear subfractions from various age groups suggested a 30% reduction for DNA binding (P less than 0.05) but not for NM with aging. Cross-incubation studies of heat-activated ER with nuclear subfractions from mice of all three age subgroups showed that this reduced DNA binding ability followed the onset of anestrous and did not result from proteolytic degradation of ER complexes.

Aging↗
PubMed1989

Angiotensin II stimulates both inositol phosphate production and human placental lactogen release from human trophoblastic cells.

We studied the functional significance of the binding of angiotensin-II (AII) to human placentas. Human trophoblastic cell suspensions were prepared by trypsin digestion of minced tissue. Cell incubations with increasing doses of [125I](SAR1)AII, ranging from 0.01-2.5 nmol/L, were carried out for 20 min at 37 C. The results indicated the presence of specific low capacity [4300 +/- 1300 (+/- SE) sites/cell], high affinity (Kd = 0.38 +/- 0.06 nmol/L) binding sites for [125I](Sar1)AII. This binding was specific for AII analogs. When placental cells were preloaded with 40 microCi/mL [3H]myoinositol for 2 h at 37 C, AII stimulation resulted in a dose-dependent increase in inositol phosphate (InsP) production [EC50 = 1.4 +/- 0.4 (+/- SE) nmol/L], as measured by ion exchange chromatography. (Sar1)AII also stimulated InsP production, with an EC50 of 0.3 +/- 0.2 nmol/L. AII-stimulated production of InsP was completely blocked by the antagonist (Sar1,Ala8)AII. AII also stimulated human placental lactogen release from trophoblastic cells in a dose-dependent fashion. The EC50 was 18 +/- 9 pmol/L, and the stimulation was blocked by (Sar1,Ala8)AII, as found for AII-stimulated InsP production. These results suggest that stimulation of human placental lactogen release by AII may be mediated by activation of phospholipase-C, which, in turn, produces phosphoinositide breakdown. The results, therefore, provide evidence of a physiological role for the renin-angiotensin system within the human placenta.

Angiotensin II↗
PubMed1989

Basal and stimulated LHRH receptor sites in the pituitary of aging female mice.

We studied the regulation of pituitary luteinizing hormone-releasing hormone (LHRH) receptors in female mice aged 4-8 months (young), 10-14 months (middle-aged) and 15-18 months (old). In intact animals the mean +/- SE pituitary content of LHRH receptor sites ranged from 34.4 +/- 6.3 fmoles to 41.5 +/- 5.0 fmoles and remained constant throughout aging. Similarly, receptor affinity for LHRH was unaltered (range 1.0-4.0 X 10(9) M-1) by age. Ovariectomy (ovx) resulted in a 30-50% decrease in pituitary LHRH receptor sites (p less than 0.05) and the pattern of LHRH receptor fall after ovx was similar in all three age groups. Administration of estrogens (E2) at either a low (0.2 mg) or a high (2.0 mg) concentration to ovx mice prevented this fall in LHRH receptor sites and, in all three age groups, increased pituitary values to levels comparable to those measured in intact animals. We conclude that there are no significant differences in the basal and stimulated number or affinity of pituitary LHRH receptors between young, middle-aged and aged female mice.

Aging↗
PubMed1988

Functional opioid receptor sites in human placentas.

We characterized the presence of opioid peptide receptor sites in plasma membranes and cells from human midterm and term placentas. Incubations with [3H]ethylketo-cyclazocine (EKC) at increasing doses revealed the presence of high affinity, low capacity, opioid peptide receptor-specific binding of the kappa-type. Scatchard analysis of the binding data showed, in the plasma membranes, linear plots at both stages of pregnancy with similar mean equilibrium association constants of 1.31 +/- 0.29 (+/- SE) X 10(9) mol/L-1 (n = 4) at midterm and 0.52 +/- 0.63 X 10(9) mol/L-1 at term (n = 4). In placental cells (n = 4) from term gestations, the binding plots were curvilinear; the first component had a Ka of 5.51 +/- 0.50 X 10(9) mol/L-1, and the second component had a Ka of 1.33 +/- 0.81 X 10(8) mol/L-1 (P less than 0.01). When standardized per mg tissue protein, the number of binding sites in plasma membranes increased from 13.8 +/- 9.8 fmol at midterm to 50.0 +/- 18.6 fmol at term (P less than 0.05). For term placental cells, the concentration of binding sites was 81.2 +/- 36.0 fmol for the high affinity sites and 713 +/- 390 fmol for the lower affinity sites. Specificity for the kappa-type of OPR was found based on the inability of mu- or delta-opioid peptides, as well as LHRH and TRH, to compete for [3H]EKC binding. Term placental cells incubated with various doses of opioid peptides had a 50% increase in placental lactogen production. The increase was significantly higher than controls only with kappa-agonists (P less than 0.05), maximal with 10(-9) mol/L EKC, and completely inhibited by 5 X 10(-6) mol/L naloxone. These results expand on previous data demonstrating the presence of opioid peptide receptor in placental plasma membranes and suggest a role for opioid peptides in regulating secretion of placental lactogen by placental cells.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1987

The relationship of tubal infertility to barrier method and oral contraceptive use.

We studied past contraceptive use in 283 nulliparous infertile women who had a diagnosis of tubal adhesions or occlusion and in 3833 women admitted for delivery at seven collaborating hospitals from 1981 to 1983. The relative risk of tubal infertility associated with barrier contraceptive use or oral contraceptive use was calculated using multivariate logistic regression to control for confounding by region, age, religion, education, smoking, number of sexual partners, time since menarche, and use of other contraceptive methods. Women who had ever used barrier methods of contraception were at a significantly decreased risk of tubal infertility (relative risk = 0.6; 95% confidence limits, 0.5 and 0.8). When type of barrier method used for the longest time was evaluated, those who used the diaphragm or condoms plus spermicides were at lower risk than those who used condoms or spermicides alone. Overall, past use of oral contraceptives neither increased nor decreased a woman's risk of tubal infertility, but there was evidence that the association between oral contraceptives and tubal infertility may vary by the amount of estrogen and type of progestogen in the oral contraceptive used. We conclude that contraceptive users who use barrier methods that combine both a mechanical and chemical barrier, such as diaphragms, cervical caps, and condoms plus spermicides, have the clearest protection against tubal damage.

Adult↗
PubMed1987

Enhanced inhibition of estrogen receptor nuclear binding in the uterus of aged mice.

We have studied why uteri from aging mice show a decrease nuclear concentration of estrogen receptors (UER). While 50-60% of available cytosolic UER from ovariectomized (OVX) mice aged 4-8 months, upon physiochemical activation, are able to bind either to DNA-cellulose or nuclear suspensions from young animals, only 20-30% of comparable concentrations of cytosolic UER from mice aged 15-18 months did so under identical experimental conditions. Nuclear dilutions with uterine cytosolic fractions from estrogen treated OVX mice prior to determination of [3H] UER binding sites in nuclear suspensions decreased the number of nuclear ER sites in both age groups. However, we observed that cytosols from aged animals showed a greater ability to prevent [3H]E2 binding to nuclear sites when compared to young ones (inhibition index: 0.286 +/- 0.013 (SE) vs. 0.137 +/- 0.025, P less than 0.05). These changes occur independently of protein concentration and result from dilution of a specific endogenous inhibitor of [3H]E2 binding to nuclear sites. The significance of these observed differences is discussed.

Aging↗
PubMed1987

Tamoxifen citrate therapy in male infertility.

A prospective, randomized, double-blind study with crossover, using tamoxifen (TAM) (Nolvadex, ici Pharma, Missisauga, Canada) 20 mg/day and placebo (p) for 6 months each, was conducted in 16 infertile men with idiopathic oligozoospermia. Baseline sperm count was 17.092 +/- 3.09 (10(6)/ml). Hormonal profile was performed and included follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), testosterone (T), prolactin (PRL), thyroid-stimulating hormone (TSH), and luteinizing hormone-releasing hormone (LH-RH) stimulation tests. The sperm analysis and hormonal profile were repeated at 6 and 12 months of the study. A sperm penetration assay (SPA) was performed on zona-free hamster egg. Compared with the placebo group, the TAM group showed a significant increase in plasma FSH, LH, E2, and T levels (P less than 0.001), but not in PRL and TSH levels. However, LH-RH stimulation tests and SPA were found to be comparable in the two treatment groups, and there was no significant effect on sperm analysis. Tamoxifen appeared to be no more effective than the placebo in the treatment of idiopathic oligozoospermia.

Adult↗
PubMed1987

The association between smoking and female infertility as influenced by cause of the infertility.

Smoking histories were compared in 901 women with infertility of different types and 1264 women admitted for delivery at seven collaborating hospitals. The relative risk for infertility associated with cigarette smoking prior to the infertility diagnosis for nulliparous cases or first live birth for controls was calculated using a multivariate logistic-regression model to control for potential confounding factors, including center, age, religion, education, number of sexual partners, and contraceptive use. The adjusted risk for infertility attributed primarily to cervical factor (n = 96) was 1.7 (P = 0.04), to tubal disease unrelated to endometriosis (n = 225) was 1.6 (P = 0.009), to ovulatory factor (n = 389) was 1.0 (not significant [NS]), and to endometriosis (n = 191) was 0.9 (NS). The authors conclude that cigarette smoking is significantly associated only with certain types of primary female infertility.

Adult↗