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Biomedical subjects

F Béguin

Publications and source records attributed to F Béguin.

At least 19 recordsLinked to original sources
PubMed2006

Thermodynamic and neutron scattering study of hydrogen adsorption in two mesoporous ordered carbons.

Two mesoporous ordered carbon materials (MOCs) have been synthesized from silica templates by using sucrose as the carbon precursor. The textural characterization using Ar, N2, and CO2 adsorption combined with neutron diffraction showed that the two samples exhibit a significant microporous volume close to 0.5 cm3/g and an ordered network of mesopores. For both MCM48 and SBA15 templated carbons, adsorption first proceeds with the filling of micropores and then by the filling of mesopores with an adsorption energy close to the enthalpy of vaporization of bulk hydrogen. The hydrogen isosteric heat of adsorption in the micropores (6-8 kJ/mol) is significantly larger than that on the graphite surface (approximately 4 kJ/mol) but still too small for a reasonable use of these MOCs as hydrogen adsorbents for storage at room temperature. The neutron scattering study showed that the structure at 10 K of the adsorbed deuterium phase is poorly organized; it exhibits short and medium range orders of about 13 angstroms in micropores and about 20 angstroms in mesopores, respectively. The average distance between adsorbed molecules decreases with coverage by about 10%. In the mesopores, the diffracted line is consistent with a pseudohexagonal packing.

Journal Article↗
PubMed1996

Is intrapartum vibratory acoustic stimulation a valid alternative to fetal scalp pH determination?

OBJECTIVES: To determine the association between fetal heart rate accelerations, whether spontaneous or induced by vibratory acoustic stimulation, and subsequent scalp pH values in presence of a suspicious intrapartum fetal heart rate tracing, and thereby assess the ability of accelerations to predict a concurrent normal fetal scalp blood pH. DESIGN: Prospective observational study of 253 labours involving 421 pH samples. SETTING: Tertiary care university hospital of Genoeva. INTERVENTION: Vibratory acoustic stimulation through the maternal abdominal wall for five seconds prior to fetal blood sampling. MAIN OUTCOME MEASURES: Spontaneous fetal heart rate reactivity (accelerations) in the 10 min preceding vibratory acoustic stimulation, vibratory acoustic-induced reactivity prior to fetal blood sampling, and scalp pH value. RESULTS: The positive predictive value of a reactive fetal heart rate response after vibratory acoustic stimulation was 78% (95% CI 73-84%) and 97% (95% CI 94-99%) for scalp pH values of > 7.25 and > or = 7.20, respectively. Similar observations occurred with spontaneous reactivity. Of concern, 7 out of 31 (23%) occasions where the scalp blood pH was less than 7.20 appeared to be associated with a normal fetal heart rate response to vibratory acoustic stimulation. CONCLUSION: Fetal heart rate acceleration induced by vibratory acoustic stimulation was significantly associated with a normal scalp blood pH higher than 7.25. However, vibratory acoustic stimulation offers no advantage over observation of spontaneous fetal heart rate tracings and cannot safely replace fetal blood sampling during labour.

Acoustic Stimulation↗
PubMed1995

Successful term pregnancy after Mustard operation for transposition of the great arteries.

Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring.

Adult↗
PubMed1992

Serum and intracellular magnesium during normal pregnancy and in patients with pre-eclampsia.

OBJECTIVE: To determine the serum and lymphocyte magnesium concentrations during normal pregnancy and to compare the magnesium status in the third trimester of pregnancy between women with normal pregnancy and those with gestational hypertension (GH) or pre-eclampsia (PE). DESIGN: A prospective cross-sectional study followed by a prospective comparative study. SETTING: Department of Obstetrics and Gynecology, Department of Pediatrics and Genetics, Hôpital Cantonal Universitaire Genève, Switzerland. SUBJECTS: Seventy-one healthy pregnant women, with normal pregnancies between 6 and 38 weeks gestation. The second part included 43 women in the third trimester of pregnancy, 11 had GH, 11 had PE and 21 formed the comparison group of healthy normotensive women. MAIN OUTCOME MEASURES: Total serum and intralymphocytic Mg concentrations and urinary Mg excretion. RESULTS: There was a progressive reduction in total serum magnesium concentrations during normal pregnancy, thought to be partly due to haemodilution, because the decline in concentration of serum proteins paralleled that of Mg (P less than 0.001). In the three groups studied in the third trimester the serum Mg concentration was very similar in the GH and the comparison groups, but it was significantly higher in the PE group (P less than 0.01). The intralymphocytic Mg concentrations and the urinary Mg excretion were similar in all three groups. In five patients treated with MgSO4 there was a large increase in the serum Mg concentration and in the urinary Mg excretion. The intralymphocytic Mg concentration remained remarkably stable. CONCLUSIONS: Our data does not support the conclusion that Mg deficiency is the primary cause of pre-eclampsia.

Cross-Sectional Studies↗
PubMed1990

Pregnancy in a patient with treated Wilson's disease: a case report.

Pregnancy should have a successful outcome in a patient with treated Wilson's disease if complications are excluded before conception. Chelating treatment must be maintained, although there is some concern about its teratogenicity. We describe the course of pregnancy in a patient followed up in our department.

Adult↗
PubMed1987

[The contraction stress test by nipple stimulation: an alternative to the oxytocin test].

Breast stimulation as a "contraction stress test" has been proposed as an alternative test to oxytocin to check the well being of the fetus. 162 breast stimulation tests were carried out in 146 patients with an indication for a "contraction stress test". The stress rate was 66.6%. 8% of the tests showed hyperstimulation without any fetal complications. There was no difference between the types of patients where the test was successful, failed or resulted in hyperstimulation. Where the tests failed, oxytocin tests were carried out. The time needed for these was, on the whole, double that taken for the breast stimulation tests. The two techniques can be comparable, both from correlation of the results with the indication and the outcome for the infant. The mothers tolerated the breast stimulation test very well indeed.

Adult↗
PubMed1986

[Maternal serum gamma-glutamyltransferase and prenatal diagnosis of the fetal alcohol syndrome].

In order to investigate prospectively the relationship between maternal serum levels of a biologic marker of alcohol and the outcome of pregnancy, we measured serum gamma-glutamyltransferase in 541 women between 14 and 20 weeks of pregnancy. An abnormally elevated value was observed in 6.8% of the cases but only 16.2% of these suspected alcohol abusers admitted drinking practices during pregnancy. Analysis of obstetrical issue and blind examination of the newborns showed a significant correlation between raised gamma-glutamyltransferase levels and an increased incidence of pre-/perinatal complications, congenital anomalies and intrauterine growth retardation. However, the sensitivity of this test is weak, limiting its use in the early recognition and prevention of fetal alcohol effects.

Adult↗
PubMed1985

[Dynamic tests for monitoring fetal cardiac rhythm].

The oxytocic test was compared in 354 cases of "high risk" pregnancy with the simple recording of fetal heart rate. When the tracing of the simple recording was normal, the oxytocic test revealed a frankly pathological tracing in only 2.5 p. cent of cases. By contrast, if there were abnormal signs in the simple record, the oxytocic test was pathological in only 18.8 p. cent of cases. The test has only a relative value, as indicated by analyses of modes of labor and of the state of the child at birth.

Female↗
PubMed1984

In vitro production of pregnancy-associated plasma protein A by human decidua and trophoblast.

Immunohistochemical techniques and direct measurements of pregnancy-associated plasma protein A (PAPP-A) have demonstrated the presence of PAPP-A in trophoblast and decidua. The purpose of the present study was to investigate the possibility that these tissues are capable of producing PAPP-A in vitro. Trophoblast and decidua were obtained from term deliveries and from legal surgical terminations of pregnancy (7 to 12 weeks). In addition to trophoblast and decidua, myometrium was also obtained during two hysterectomies in the first trimester of pregnancy. Tissues were incubated in medium 199 at 37 degrees C under an oxygen/carbon dioxide atmosphere. Media containing either pregnancy-associated serum or non-pregnancy-associated serum were changed after 8 hours of incubation in medium 199 alone. In addition to PAPP-A, human placental lactogen (hPL) and prolactin (Prl) were measured in homogenates and media by radioimmunoassays in order to confirm the viability of the cultured tissues. Addition of pregnancy-associated serum to the media induced a significant release of PAPP-A from trophoblast and decidua when compared to that in control cultures. Non-pregnancy-associated serum had no effect. Myometrium did not release any measurable PAPP-A into the medium even in the presence of pregnancy-associated serum. Cycloheximide added to pregnancy-associated serum significantly inhibited the release of PAPP-A from trophoblast and decidua. These last tissues, irrespective of the culture condition, released significantly more PAPP-A as well as hPL and Prl than was initially present in the tissue. These data demonstrate that PAPP-A is released in vitro by trophoblast and decidua (but not by myometrium) and that this release can be magnified by a factor present only in pregnancy-associated serum. The release of PAPP-A, hPL, and Prl is considered as a de novo production since concentration of these proteins are higher in media and tissues after incubation compared to concentrations initially present in the tissue before culture and since cycloheximide significantly inhibits the release of PAPP-A, Prl, and hPL from the cultured tissues.

Culture Media↗
PubMed1984

[Gamma-glutamyltransferase in maternal serum and prenatal screening for the fetal alcohol syndrome].

In order to investigate prospectively in pregnant women a correlation between serum levels of a biological marker of alcohol and the clinical status of the newborn, we measured the gamma-glutamyltransferase (GGT) in 630 women between 14 and 20 weeks of pregnancy. In 7% of the cases, an elevated value was observed while history confirmed alcohol consumption in only 1%. Preliminary statistical analysis established upon the blind examination of 308 newborns show a correlation between maternal GGT levels and birthweight as well as the pre- and perinatal complications. However, the sensitivity of this test is weak.

Female↗