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Biomedical subjects

M Bogaert

Publications and source records attributed to M Bogaert.

At least 37 records · Page 2Linked to original sources
PubMed1989

EEG and SEMG monitoring during induction and maintenance of anesthesia with propofol.

Propofol has been used as IV induction (2 mg/kg) and maintenance agent (150 micrograms/kg/min and 100 micrograms/kg/min after 30 min), combined with N2O/O2 in 16 premedicated (atropine 0.5 mg, Thalamonal 2 ml IM) and mechanically ventilated patients, having ear surgery or arthroscopy. Cranial biopotentials were analysed by 2 different techniques: 1. The Anesthesia and Brain Activity Monitor (ABM Datex) providing the zero crossing frequency (ZXF) as a value for the mean frequency of the EEG signal during a considered time interval, the mean integrated voltage (MIV) as a mean value of the amplitude of the same EEG signal and the spontaneous electromyography of the frontal muscle (SEMG). 2. The EEG trend monitor (rough signal, spectral analysis (S.A.), procentual display). The EEG changes, recorded during propofol anesthesia, are comparable with both techniques. Induction is characterised by a decrease in ZXF, caused by a procentual increase in the low frequency bands (the delta band represents more than 80% of the total power). During the perfusion period an increase in the power of the alpha band (10% to 40%) and a decrease in the delta band is noticed. The ZXF regains its original value. At the end of the procedure the ZXF increases (beta band to more than 30%). A correlation was looked for between the EEG changes and the propofol blood concentrations. The higher the propofol blood concentrations, the more pronounced the low frequency bands. The appearance of beta waves or a ZXF greater than 10 Hz indicates pending arrousal.

Adolescent↗
PubMed1989

[Patient-oriented package inserts for drugs. Historical overview and current status].

After a short note on terminology, in this review article a survey is given of former and existing initiatives concerning the Patient Package Insert (PPI) in the USA and in Western Europe, with emphasis on the situation in Belgium. Arguments in favour of and against the PPIs are given, based upon the literature. The need for drug information for the general public is illustrated by a number of studies. Content and presentation of the PPI as a source of drug information are discussed. Studies on the impact of PPIs on satisfaction, knowledge, compliance, adverse drug reactions emotions, risk/benefit-decisions etc. are reviewed. Finally, attention is drawn to remaining problems and to the needs for further research.

Belgium↗
PubMed1988

The dissolution rate and bioavailability of hydrochlorothiazide in pellet formulations.

The influence of non-active ingredients in the manufacture of pellets on in-vitro dissolution rate and on bioavailability of hydrochlorothiazide has been studied. Pellets were formulated using either microcrystalline cellulose or microcrystalline cellulose-carboxymethylcellulose sodium blends as matrix, and hydrochlorothiazide as the active ingredient. In-vitro drug release from the different pellet formulations was retarded in comparison to a conventional tablet formulation and was dependent on the nature of the non-active ingredient and, for the microcrystalline cellulose-carboxymethylcellulose sodium blend, of the dissolution medium. In-vivo bioavailability of both pellet formulations was low compared with that of the conventional tablet and the plasma concentration-time profiles did not suggest slow release.

Adult↗
PubMed1984

In vitro study of the influence of dopamine on rat and dog gastric fundus.

The effect of dopamine was studied in rat longitudinal fundus strips and in dog circular and longitudinal fundus strips. Contractions of similar amplitude were induced by transmural stimulation and by methacholine. In the rat, dopamine inhibits the electrically induced contractions partially by a post-junctional influence on the smooth muscle cells and partially by inhibiting the release of acetylcholine from the intramural cholinergic neurons. The latter effect is antagonized by phentolamine, while the former is antagonized by propranolol. Dopamine antagonists change the inhibitory effect of dopamine to a small degree but have a similar influence on the inhibitory effect of noradrenaline. The inhibitory effect of dopamine is largely indirect through the liberation of noradrenaline, since in the presence of cocaine or after reserpine-pretreatment the inhibition by dopamine is markedly reduced. In the presence of propranolol, cocaine and hydrocortisone, the inhibitory effect of dopamine is equally antagonized by the alpha 1-antagonist prazosin and the alpha 2-antagonist rauwolscine. In the dog, the inhibition of the electrically induced contractions by dopamine is mainly due to inhibition of the release of acetylcholine from the intramural cholinergic neurons. This effect is not influenced by the presence of cocaine and is completely antagonized by phentolamine and rauwolscine, while prazosin has no effect. From the dopamine antagonists tested, only metoclopramide had some antagonistic effect against dopamine but it antagonized to the same degree the inhibition by noradrenaline.

Animals↗
PubMed1984

8-Methoxypsoralen plasma levels and phototoxic effect.

In 8 normal volunteers, the minimal phototoxic dose was determined at 15 min intervals up to 60 min and thereafter every 30 min up to 4 h; 8-methoxypsoralen (8-MOP) was administered as a solution and small additional doses were given during the course of the experiment, so that a more or less predictable and stable plasma concentration was obtained and maintained for about 2 h. Three of the subjects absorbed 8-MOP very rapidly, already reaching plasma concentrations above 200 ng/ml after 15 min; in the other 5, absorption was slower and comparable levels were achieved only after 30 to 90 min. In the fastest absorbers, there was a 15 to 30 min lag between reaching a high plasma level and a low MPD. In the other cases, such a delay was not seen. This suggests that the time to reach peak concentration in the skin is not influenced by changes in absorption rate: simulations based on the classical plasma concentration equations for a two-compartmental model also show this. Afterwards, the skin sensitivity decreased in most cases parallel to the plasma concentrations.

Female↗
PubMed1983

The progress of patients in the European Working Party on Hypertension in the Elderly trial.

792 hypertensive patients above the age of 60 have entered the double-blind multicentre trial of the European Working Party on High blood pressure in the Elderly (EWPHE). Half were treated with hydrochlorothiazide and triamterene and half were given placebo and a second capsule was given and if necessary up to 2 g of methyldopa/day. The measurements in a sample of 157 patients suggested 80-86% compliance rate. A significant blood pressure difference of 25/10 mm Hg was obtained between the groups and maintained during five years of follow-up. The increase in serum creatinine found in the actively treated group was related to the decrease in sitting systolic blood pressure. Changes in serum uric acid correlated with changes in serum creatinine both in the placebo and in the actively treated group. Fasting blood glucose changed significantly in the active treatment group. The balance between this decreased risk on the basis of the blood pressure reduction and the increase produced by the rise in blood glucose and the other treatment effects remains to be determined. The trial continues and more patients are being admitted.

Aged↗
PubMed1983

The production in high yield of N'-(4-[11C]methyl)-imipramine.

A method for the routine production in high yield of N'-(4-[11C]methyl)-imipramine is presented. The label is incorporated by reaction of C-11 methyl iodide (11CH3I) upon desipramine in dimethylsulfoxide. Quaternization of the tertiary amine by 11CH3I is minimized by using an excess of desipramine. The reaction proceeds at room temperature for 10 min and the product is isolated by means of high-performance liquid chromatography (HPLC). The entire production takes only 40 min and results in a radiochemical yield of 60%. About 60 mCi of labeled product are available for medical application; the specific activity, at the time of use, is 50 mCi/mumole. The product was characterized by chromatographic and spectrometric methods.

Carbon Radioisotopes↗
PubMed1983

Peritoneal pharmacokinetics of gentamicin in man.

The peritoneal pharmacokinetics of gentamicin were investigated in patients on continuous ambulatory peritoneal dialysis. Gentamicin was added to the dialyzate, and gentamicin concentrations were measured repeatedly in serum and dialyzate. After administration of a single dose of gentamicin, equilibrium between serum and dialyzate levels is achieved within 24 hours; dialyzate levels of gentamicin are lower and mass transfer coefficients higher in patients with peritonitis. With chronic intraperitoneal gentamicin treatment for peritonitis, steady state serum levels around 4 to 5 mg/l are achieved and otovestibular toxicity should be feared.

Ascitic Fluid↗
PubMed1982

Antihypertensive therapy in patients above age 60 with systolic hypertension. A progress report of the European Working Party on High Blood Pressure in the Elderly (EWPHE).

1. Although systolic blood pressure elevation is responsible for increased incidence of cardiovascular accidents in old people, the preventive benefit of lowering systolic hypertension in elderly has not been confirmed. 2. A double blind study comparing the effects of a placebo and of an active regimen (hydrochlorothiazide-triamterene with or without methyldopa) in people over 60 years with isolated systolic hypertension has been undertaken by the European Working Party on High blood pressure in the Elderly (EWPHE). 3. The actively treated group shows a lowered sitting blood pressure (-15/6 mm Hg), a mild increase of serum creatine, serum uric acid and blood glucose and a mild decrease of serum potassium after two years of treatment when compared to the spontaneous changes observed in the placebo treated group. 4. The study is continuing to evaluate if the blood pressure reduction prevents or reduces the incidence of cardiovascular accidents, although some biochemical changes were provoked by the treatment.

Aged↗
PubMed1982

The combined effect of theophylline and terbutaline in patients with chronic obstructive airway diseases.

Using a double-blind, cross-over design the acute bronchodilating effect of 375 mg microcrystalline theophylline, 5 mg terbutaline, a combination of both drugs and placebo was studied in 11 patients suffering from moderate to severe chronic obstructive lung disease with partially reversible airway obstruction. Plasma concentrations both theophylline and terbutaline were measured. The bronchodilation produced by oral intake of 5 mg terbutaline and 375 mg theophylline was comparable. The maximal median value of terbutaline in plasma was 4.6 ng/ml 2 h after intake of medication, followed by a decline with a double peak in some patients. The maximal median increase of FEV1 was 37% 3 h after intake of medication. The maximal median plasma level of theophylline reached 12.5 ng/ml 30 min after intake of the medication. The median maximal increase of FEV1 was 24%. One hour after intake of medication and throughout the whole test period up to 7 h, the combination of 5 mg terbutaline and 375 mg theophylline produced a significantly greater bronchodilation than each drug alone. It is concluded that 375 mg microcrystalline theophylline produced a significantly greater bronchodilation than each drug alone. It is concluded that 375 mg microcrystalline theophylline and 5 mg terbutaline produces almost equal bronchodilating activity: a combination of both drugs, however, results in further bronchodilation.

Administration, Oral↗
PubMed1981

Lidocaine plasma concentrations obtained with a standardized infusion in the awake and anaesthetized dog.

Lidocaine was administered intravenously on several occasions to three healthy mongrel dogs. The lidocaine treatment consisted of an infusion of 0.8 mg/kg/min over 10 min, followed by an infusion of 0.085 mg/kg/min over 3 h. This lidocaine treatment was given once in the awake state and on two other occasions the infusion was started before or during the following anaesthetic regimen: atropine-meperidine premedication, thiopental induction and maintenance nitrous oxide-methoxyflurane anaesthesia. In most instances plasma levels were somewhat higher at the end of the loading infusion (greater than 5 micrograms/ml) than subsequently, but steady-state values were obtained soon after starting the 3-h infusion. There were no striking differences between the plasma profiles and half-lives found in the three series of experiments: mean plasma concentrations of lidocaine during steady state were between 3.5 and 5.0 micrograms/ml and the half-life of lidocaine was 1 to 2 h. Signs of intoxication were not seen in any of the dogs at any stage of the procedures. It is concluded that with the loading and maintenance doses used in this study steady-state values, probably within the therapeutic range, are obtained within a few minutes. The plasma concentrations are not influenced by the anaesthetic regimen used.

Anesthesia↗
PubMed1980

Randomized trial of two beta-mimetic drugs (ritodrine and fenoterol) in acute intra-partum tocolysis.

The uterine inhibitory effect and potential maternal and fetal side effects of two beta-mimetic compounds, ritodrine hydrochloride and fenoterol hydrobromide, were compared in a randomized trial. The drugs were administered by intravenous infusion to 24 healthy term nulliparous women during effective first-stage labour; each of them received fenoterol (1, 2, or 4 microgram/min) or ritodrine (100, 200, or 400 microgram/min). There was no difference between the drugs in the intensity of the uterine inhibition. However, for a similar inhibitory effect, the duration of tocolysis was longer after ritodrine. During the intrapartum and neonatal periods, neither compound induced any change in the fetal parameters investigated, and their effects on maternal parameters were comparable.

Blood Pressure↗
PubMed1980

Adaptation of the dose of mexiletine according to pharmacokinetic data.

Although pharmacodynamic factors are very important in regard to the need for dose adaptation of mexiletine, pharmacokinetic factors also play a role. Pharmacokinetic variability for mexiletine is mainly due to interindividual differences in biotransformation rate in patients with normal hepatic function. Whether the existence of a compromised renal, hepatic or cardiac function alters dosage requirements is not clear. Oral administration of three times 250 mg daily is probably a good starting dose but adaptation will be necessary in many patients. The need for a loading dose depends on the urgency of the situation. For the intravenous administration a loading dose is always necessary. A regimen consisting of 100 to 250 mg mexiletine over 10 minutes, followed by 200 mg over 1 hour has been proposed. This is then followed by a continuous infusion of 0.5-2.5 mg/min. Pharmacodynamic variations notwithstanding, it is of interest to obtain plasma levels of mexiletine within the range of 1-2 microgram/ml.

Administration, Oral↗