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S De Cooman

Publications and source records attributed to S De Cooman.

13 recordsLinked to original sources
PubMed2001

Air-oxygen mixtures in circle systems.

STUDY OBJECTIVE: To determine the effect of different air-O(2) mixtures and fresh gas flows (FGF) on the relationship between the delivered (F(Del)O(2)) and inspired O(2) fraction (FIO(2)) in a circle system. STUDY DESIGN: Randomized clinical study. SETTING: Large teaching hospital. PATIENTS: 160 ASA physical status I, II, and III patients undergoing a variety of cardiovascular procedures with general endotracheal anesthesia. INTERVENTIONS: 160 patients were randomly assigned to one of 20 groups (n = 8 each), depending on the combination of total FGF (0.5, 1, 2, 4, or 8 L/min) and air-O(2) mixture used (ratios of 4/1, 3/2, 2/3, or 1/4), corresponding to a F(Del)O(2) of 0.37, 0.53, 0.68, and 0.84. For each combination of FGF and air-O(2) mixture, FIO(2) after equilibration was compared with F(Del)O(2). MEASUREMENTS AND MAIN RESULTS: With any air-O(2) mixture with a FGF < or = 2 L/min, FIO(2) became lower than F(Del)O(2). Because FIO(2) decreased below 0.25 after 13 and 26 minutes in the first two patients of the 4/1 0.5 L/min air-O(2) group, this study limb was terminated. CONCLUSIONS: When using air-O(2) mixtures in a circle system, FIO(2) becomes lower than the F(Del)O(2) with FGF < or = 2 L/min. The relative proportion of O(2) in the FGF has to be increased accordingly.

Air↗
PubMed2001

The ADU vaporizing unit: a new vaporizer.

UNLABELLED: We determined the performance of the vaporizer of the ADU machine (Anesthesia Delivery Unit; Datex-Ohmeda, Helsinki, Finland). The effects of carrier gas composition (oxygen, oxygen/N(2)O mixture, and air) and fresh gas flow (0.2 to 10 L/min) on vaporizer performance were examined with variable concentrations of isoflurane, sevoflurane, and desflurane across the whole range of each vaporizer's output. In addition, the effects of sudden changes in fresh gas flow and carrier gas composition, back pressure, flushing, and tipping were assessed. Vaporizer output depended on fresh gas flow, carrier gas composition, dial settings, and the drug used. Vaporizer output remained within 10% of dial setting with fresh gas flows of 0.3-10 L/min for isoflurane, within 10% of dial setting with fresh gas flows of 0.5-5 L/min for sevoflurane, and within 13% of dial setting with fresh gas flows of 0.5 to 1 L/min for desflurane. Outside these fresh gas flow ranges, output deviated more. The effect of sudden changes in fresh gas flow or carrier gas composition, back pressure, flushing, and tipping was minimal. We conclude that the ADU vaporizer performs well under most clinical conditions. Despite a different design and the use of complex algorithms to improve accuracy, the same physical factors affecting the performance of conventional vaporizers also affect the ADU vaporizer. IMPLICATIONS: The ADU vaporizer performs well under most clinical conditions. Despite a different design and the use of complex algorithms to improve accuracy, the same physical factors affecting the performance of conventional vaporizers also affect the ADU vaporizer.

Anesthesiology↗
PubMed1994

The probability of a successful treatment of infertility by in-vitro fertilization.

The objective of this study was to define several estimates of the success rate of in-vitro fertilization and embryo transfer treatment in relation to treatment outcome. The data were collected in a retrospective study of 591 patients treated during 3 years in one Belgian university hospital. Several models used for evaluating the treatment of infertility were fitted to the data (logistic model, binomial model, double binomial model, exponential model, the Speirs model. The number of oocytes retrieved and the proportion of fertilized oocytes at the first attempt can be used as prognostic factors. According to these factors, the success rate after five attempts varies from 28 to 88%.

Belgium↗
PubMed1993

Plasminogen activator activity and fertilizing ability of human spermatozoa.

Mature spermatozoa contain a number of proteases that are supposed to contribute to their fertilizing ability. The present study was directed at plasminogen activator (PA), a protease that belongs to the group of serine proteases and converts the zymogen plasminogen to the active broad-spectrum protease plasmin. To investigate the possible role of PA in the fertilization process, we have measured sperm-bound PA activity in 63 patients included in an in-vitro fertilization (IVF) programme and assessed their relationship to standard semen parameters and the rate of fertilization. PA activity was correlated significantly with the sperm count, as well as with sperm motility and morphology. Using logistic regression analysis, specific PA (pmol pNA 10(-6) cells min-2) was found to significantly influence the probability of fertilization. Other significantly predictive factors were motility and the percentage of spermatozoa with normal morphology. The sperm concentration (10(6) cells ml-1) did not significantly affect the outcome of IVF. We suggest that sperm-bound PA is involved in the fertilization process and may represent a potential indicator of sperm fertilizing capacity.

Female↗
PubMed1993

Effects of hyaluronate, strontium and prolonged incubation on different sperm parameters.

The aim of this study was to evaluate the effect of hyaluronate and strontium with short and prolonged incubation periods on different sperm parameters. For sperm intended for in vitro fertilization good progressive motility, a high percentage of normal form, a suitable linear velocity and a low acrosome-reacted proportion of sperm are required. The semen washing procedure in the self-migration method with medium containing hyaluronate Ca2+ after 3 h of incubation complies better with these criteria.

Acrosome↗
PubMed1992

Low bone mass in hypogonadal males. Effect of testosterone substitution therapy, a densitometric study.

Sixteen (16) male patients who were suffering from hypogonadism but who were free from bone symptoms were recruited from the Andrology Clinic. Their bone mineral density (BMD) was assessed by single photon absorptiometry in the non-dominant radius, at both the distal radius (DR) (27% trabecular bone) and the midshaft radius (MR) (90% cortical bone). Measurements were carried out before and during testosterone substitution therapy. BMD was found to be lower in the subjects than in the controls, to a similar extent at both the DR (0.47 +/- 0.02 g/cm2, i.e. 83.1 +/- 4.3% of the value in the controls, or Z score -1.42 +/- 0.39; P less than 0.01) and the MR (0.68 +/- 0.02 g/cm2, i.e. 87.8 +/- 2.4% of the value in the controls, or Z score -1.49 +/- 0.33; P less than 0.01). There was no correlation between testosterone levels and BMD at either the DR or the MR at the beginning of the study. Following testosterone substitution therapy, bone mineral content (BMC) increased significantly at the DR (+5.9 +/- 1.4% per year; P less than 0.01) and at the MR (+1.1 +/- 0.9% per year; P less than 0.01). If the study is limited to the subjects who had achieved full bone age maturity before the start of therapy, the bone gain remains significant only at the DR, a site with a sizeable proportion of trabecular bone.

Adolescent↗
PubMed1987

Feminizing testicular Leydig cell tumor: hormonal profile before and after unilateral orchidectomy.

The effect of chronic hyperestrogenism on gonadal function was studied in three men who had estrogen-secreting Leydig cell tumors before unilateral orchidectomy and for 11-43 months after surgery. All three men had low plasma gonadotropin and testosterone levels and increased estradiol levels. Impairment of testicular steroidogenesis was also suggested by increased progesterone to 17-hydroxyprogesterone and 17-hydroxyprogesterone to androstenedione ratios in both spermatic venous plasma and the medium of Leydig tumor cells from one patient incubated in vitro. Before surgery, spermatogenesis was abnormal in two men. Testicular endocrine function and spermatogenesis did not return to normal after surgery. During the follow-up period, plasma gonadotropin levels were high in all three men, and testosterone was low normal. Estradiol levels decreased to normal immediately after surgery and then returned to the upper normal limit. The response to hCG stimulation in one man was subnormal. We conclude that chronic hyperestrogenism produced hypothalamo-pituitary inhibition as well as direct steroidogenic blockade at the testicular level. Long term impairment of both endocrine and exocrine testicular functions may be secondary to slowly reversible (or irreversible) estrogen-induced damage to tubular and Leydig cells.

Adult↗
PubMed1985

Fertility of male workers exposed to mercury vapor or to manganese dust: a questionnaire study.

The fertility of male workers exposed to mercury vapor or to manganese dust was assessed with the use of the questionnaire developed by Levine et al [1980]. In the mercury group (concentration of mercury in urine ranging from 5.1 to 272.1 micrograms/g creatinine), no statistically significant difference was found between the observed number of children and that expected on the basis of the reproductive experience of a well-matched control group. On the contrary, by comparison with their corresponding controls, the manganese-exposed workers exhibited a statistically significant deficit in the number of children during their period of exposure to the metal. The airborne concentration of manganese dusts at the different workplaces ranged from 0.07 to 8.61 mg/m3 with a geometric mean of 0.94 mg/m3.

Adolescent↗
PubMed1983

Immunoreactive relaxin-like substance in human split ejaculates.

Immunoreactive relaxin-like substance concentrations were estimated in whole seminal plasma of normozoospermic patients, in seminal fluid of both fractions of split ejaculates, as well as in the seminal plasma of patients affected by excretory azoospermia of various causes. The relaxin concentration was significantly higher in the first fraction of partitioned ejaculates (P less than 0.001). In cases of azoospermia after vasectomy or after epididymal obstruction, the relaxin levels were similar to the values observed in normozoospermia. Relaxin concentrations, however, were high in cases of congenital agenesis of vasa deferentia and seminal vesicles. Relaxin traced in human male seminal plasma seems thus to have an important extragonadic source, probably localized in the prostate.

Ejaculation↗
PubMed1980

Immunoreactive relaxin-like substance in human seminal plasma.

Large amounts of an immunoreactive relaxin-like peptide were demonstrated in human seminal plasma. The concentrations of this peptide were determined in seven healthy volunteers, and in twenty-eight non-selected male patients seeking advice for sterility. A wide range of immunoreactive relaxin concentrations was observed, varying between 1,240 pg and 73,000 pg of relaxin porcine equivalents per ml of seminal plasma. Given the very special assay medium of seminal plasma, particular attention was paid to the validity of the radioimmunoassay system when applied to this medium.

Fertility↗
PubMed1972

[Vasectomy].

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Humans↗