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Biomedical subjects

F Christiaens

Publications and source records attributed to F Christiaens.

29 records · Page 2Linked to original sources
PubMed1997

The effect of propofol on parthenogenetic activation, in vitro fertilization and early development of mouse oocytes.

OBJECTIVE: To assess the effect of propofol on fertilization and early embryo development in a mouse IVF model. DESIGN: Controlled study. SETTING: Mouse IVF. INTERVENTION(S): Mouse oocytes were exposed in vitro to propofol at a concentration of 0 (control), 50, 250, 500, 1,000, or 5,000 ng/mL for 30 minutes, washed, and inseminated. Thereafter, fertilization was assessed. Subsequent in vitro development to the blastocyst stage was monitored daily. The potential to activate parthenogenetically oocytes also was evaluated by looking for spontaneous extrusion of the second polar body or development to the two-cell stage. In a second step, a pure propofol solution was added to culture medium and used as a standard. MAIN OUTCOME MEASURE(S): Two-cell and blastocyst-stage embryo. RESULT(S): Where fertilization occurred, subsequent embryo cleavage and development up to the blastocyst stage was affected significantly by the presence of propofol solution in the medium, (i.e., 3% to 41%) in comparison with the control group (76%). Exposure of unfertilized oocytes for 30 minutes to propofol results in a parthenogenetic activation of 33% to 60%, which was significantly higher than the control (10%). When oocytes were kept in propofol for 24 hours, a mean of 30% of activation was observed as compared with 0.5% for the control. CONCLUSION(S): We can conclude from these experiments that even a brief exposure of cumulus-enclosed oocytes to a low concentration of propofol is deleterious to subsequent cleavage. Exposure of unfertilized oocytes to propofol results in a high degree of parthenogenetic activation.

Anesthetics, Intravenous↗
PubMed1997

Anaesthetic management of caesarean section in a parturient with acute myelodysplastic syndrome.

A 34-year-old pregnant woman developed a myelodysplastic syndrome during pregnancy which resulted in a refractory anaemia and an extreme thrombocytopenia. The report describes the anaesthetic management of elective caesarean section and successful childbirth in this patient. Following replacement therapy with packed red cells and platelets, general anaesthesia was used for the procedure.

Journal Article↗
PubMed1997

Combined cesarean section and clipping of a ruptured cerebral aneurysm: a case report.

We present a case of subarachnoid hemorrhage due to a ruptured cerebral aneurysm of the right internal carotid artery in a patient at 34 weeks of gestation (G2P1). A combined surgical procedure (cesarean section followed by clipping of the aneurysm) was performed with good maternal and fetal outcome. The differential diagnosis, the timing of neurosurgery, and the anesthetic techniques used are discussed.

Adult↗
PubMed1995

Human albumin and colloid fluid replacement: their use in general surgery.

This review considers the pharmacology and indications for use of human albumin and synthetic colloids in general and transplantation surgery. The selection of a particular agent should be based on sound knowledge of their pharmacokinetic and pharmadynamic properties together with some consideration of cost. For correction of hypovolemia, human serum albumin solutions can adequately be replaced by present day colloids such as hydroxyethyl starch solutions. The duration of their effect in the intravascular space and their properties for plasma volume substitution or expansion are the main factors that will influence their selection. Albumin solutions, however, remain useful for treatment of all acute situations of hypovolemia accompanied by hypoalbuminemia during and after surgery.

Colloids↗
PubMed1995

Malignant hyperthermia suggestive hypermetabolic syndrome at emergence from anesthesia.

A 6-year old female child received succinylcholine (1 mg.kg-1) and isoflurane (concentrations of 1.5-2 percent) and developed at the end of surgery a hypermetabolic syndrome suggestive of malignant hyperthermia (MH) with masseter muscle spasm, muscle rigidity, tachypnea, systolic hypertension (140 mm Hg), tachycardia (205 beats.min-1), hypercarbia (end expiratory CO2 71 mmHg), and an increase in body temperature (39.2 degrees C). The child responded well to therapy which included cooling, hyperventilation with pure oxygen and dantrolene administration. However, blood creatine kinase and myoglobin elevations were moderate (respectively 375 IU.L-1 and 114 micrograms.L-1) and an in vitro halothane and caffeine contracture test was negative. Differential diagnostic proposals are discussed and compared to the clinical incident.

Caffeine↗
PubMed1990

An augmented escape of beta-endorphins to suppression by dexamethasone in severely depressed patients.

Baseline beta-endorphin and cortisol levels and their responses to 1 mg dexamethasone were measured in 11 healthy controls and in 35 depressed patients, categorized according to the DSM-III. Dexamethasone significantly suppressed beta-endorphin levels. Depressed patients with melancholia/psychotic features exhibited significantly increased post-dexamethasone beta-endorphin levels compared with healthy controls, minor and simple major depressives; the baseline beta-endorphin levels did not differ between those study samples. Post-dexamethasone beta-endorphin and cortisol values were found to be significantly and positively correlated. Accordingly, cortisol non-suppressors showed significantly higher post-dexamethasone beta-endorphin levels. Post-dexamethasone beta-endorphin may be the most sensitive and specific reflection of the disorder in negative feedback exerted by dexamethasone in depression.

Adult↗
PubMed1990

Suppressant effects of dexamethasone on the availability of plasma L-tryptophan and tyrosine in healthy controls and in depressed patients.

Formation in the brain of serotonin from L-tryptophan (L-TRP) and noradrenaline from tyrosine are pathways related to the pathophysiology of major depression and to the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. In the past, decrements in L-TRP availability and disorders in the HPA axis have repeatedly been observed in major depressed patients; both factors were shown to be inversely correlated. In order to investigate the relationships between glucocorticosteroid activity and the availability of L-TRP and tyrosine, the authors measured L-TRP, tyrosine, valine, leucine, isoleucine and phenylalanine in baseline conditions and after treatment with 1 mg dexamethasone in 16 healthy controls and in 50 depressed patients. The ratios between L-TRP and tyrosine and the sums of the amino acids known to compete with them during transport across the blood-brain barrier were computed as an index of (respectively) the serotonin and noradrenaline synthesis in the brain. We found significantly decreased plasma L-TRP and tyrosine levels after treatment with dexamethasone compared with basal levels. Accordingly, the plasma ratios between L-TRP and tyrosine and the sum of the competing amino acids were significantly reduced by dexamethasone administration. It was hypothesized that through these actions of dexamethasone on peripheral amino acids, the central noradrenaline and serotonin control over the HPA-axis could be altered.

Adult↗
PubMedDate not supplied

Effects of diluent volume of a single dose of epidural bupivacaine in parturients during the first stage of labor.

BACKGROUND AND OBJECTIVES: 0.1% bupivacaine for obstetric epidural analgesia is given by infusion, using a loading dose of a higher concentration alone or in combination with opioid analgesics. A single dose of 0.1% without any additive for relief of first-stage labor pain has not yet been documented. METHODS: Fifty-eight primiparae in active labor and with less than 5 cm cervical dilatation received 20 mg epidural bupivacaine diluted in 4 mL [group 1: 0.5% (I)], 10 mL [group 2: 0.2% (II)], or 20 mL [group 3: 0.1% (III)]. Pain relief, dermatomal spread, and motor block were assessed. RESULTS: Visual analog pain scale (VAS) was significantly lower in group 2 (0.88 +/- 1.34) and group 3 (0.25 +/- 0.61) than in group 1 (4.37 +/- 2.57). Onset and time to maximum analgesia was significantly shorter in group 2 than in group 3. Mean duration of analgesia was 120 +/- 21 minutes in group 3, 100 +/- 26 in group 2, and 43 +/- 21 in group 1. The mean numbers and upper limits of dermatomes blocked did not differ between groups 2 and 3, but were higher than in group 1. Motor blocks in groups 2 and 3 were more extensive than in group 1 with no difference between groups 2 and 3. Ten mL 0.2% or 20 mL 0.1% epidural bupivacaine results in a similar degree of pain relief, superior to that following 4 mL 0.5%, while duration was longest after 20 mL 0.1%. CONCLUSIONS: Analgesia lasts significantly longer following 20 mL 0.1% bupivacaine than following 10 mL 0.2% bupivacaine when given for first-stage labor pain. Four milliliters 0.5% bupivacaine results in inadequate pain relief.

Adult↗
PubMedDate not supplied

Auditory neuropathy with preserved cochlear microphonics and secondary loss of otoacoustic emissions.

Auditory neuropathy is defined as absent or severely distorted auditory brainstem responses with preserved otoacoustic emissions and cochlear microphonics. This entity can be found in various circumstances including pre-lingual children. An almost universal characteristic reported from adult patients is the ineffectiveness of traditional hearing aids. Adequate management of pre-lingual cases therefore remains an open problem. This paper describes two pre-lingual children whose follow-up data demonstrated a selective loss of the otoacoustic emissions, whereas the cochlear microphonics remained preserved. In one of the patients, hearing aid fitting as soon as she lost her otoacoustic emissions proved successful. These findings have important implications for the operational definition of the condition, since one must be prepared to encounter cases with absent otoacoustic emissions. The present data also demonstrate that conventional amplification can benefit pre-lingual auditory neuropathy cases, at least once they have lost their otoacoustic emissions.

Adult↗