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Biomedical subjects

H De Bruin

Publications and source records attributed to H De Bruin.

5 recordsLinked to original sources
PubMed1995

Effect of an evening dose of regular and effervescent formulations of ranitidine or cimetidine on intragastric pH in healthy volunteers.

AIMS: To compare the effects on intragastric acidity of a single evening dose of either standard or effervescent formulations of ranitidine (300 mg) or cimetidine (800 mg). METHODS: Twelve healthy subjects were studied, using a four-period randomized cross-over design and an ambulatory intragastric pH monitoring technique. The subjects received a standard evening meal at 17.00 hours and one of the H2-receptor antagonist formulations was given at 23.00 hours. RESULTS: Both effervescent formulations caused a transient rapid increase in intragastric pH, reaching a maximum at about 3 min after ingestion. After both effervescent formulations a significantly higher pH was measured during the first 45 min after ingestion (P < 0.05), compared to the regular formulations. The onset of action of the H2-receptor antagonists was similar for both formulations of ranitidine and the effervescent cimetidine, but tended to be slower for the regular cimetidine (P = 0.06). Nocturnal intragastric pH was significantly increased by all four formulations, but more effectively so by the two ranitidine formulations. The duration of action (taken as time with pH > 4) of both ranitidine formulations was longer than that of both cimetidine formulations (P < 0.002). CONCLUSIONS: A single evening dose of 300 mg ranitidine produces a stronger decrease of nocturnal gastric acid secretion than 800 mg cimetidine. The effervescent formulations of both drugs offer the advantage of a rapid decrease (within minutes) of intragastric acidity, with preservation of the sustained systemic effect.

Adolescent↗
PubMed1993

Electrophysiologic and pharmacokinetic profile of the new antiarrhythmic drug TYB-3823 in humans.

In an open-label study, electrophysiology and pharmacokinetics of TYB-3823, a new antiarrhythmic compound, were investigated. Sixteen patients underwent an electrophysiologic study before and after intravenous (i.v.) administration of TYB-3823. Two patients each received the following increasing doses: 0.2, 0.4, 0.8, and 1 mg/kg. Eight patients received 1.2-mg/kg. TYB-3823 concentrations followed a biexponential decrease with a terminal half-life (t1/2) of 3.88 +/- 0.87 h. Clearance was 47.2 +/- 18.5 L/h, and volume of distribution was 250 +/- 77 L. Dose-dependent pharmacokinetics were evident. Significant effects of TYB-3823 were apparent at doses > or = 0.8 mg/kg (n = 12), including increase in the AH and HV interval from 92 +/- 17 to 105 +/- 19 ms (p < 0.002) and 47 +/- 7 to 60 +/- 12 ms (p < 0.005), respectively. QRS duration was prolonged from 100 +/- 16 to 126 +/- 22 ms (p < 0.001), accompanied by an increase of the corrected QT interval from 425 +/- 28 to 465 +/- 37 ms (p < 0.002). The corrected JT interval remained unchanged, however, refractoriness did not change, but monophasic action potential duration (APD) tended to decrease. TYB-3823 appeared effective against reinduction of all arrhythmias observed during the control study [atrial fibrillation, atrioventricular (AV) nodal tachycardias]. TYB-3823 depresses conduction velocity significantly without prolonging refractoriness. Therefore, TYB-3823 may be classified as a class 1C antiarrhythmic. On the basis of the present results, additional class 1B activity cannot be excluded. TYB-3823 has antiarrhythmic properties, appears to be devoid of proarrhythmic effects, and is well tolerated.

Action Potentials↗
PubMed1992

Absence of guar efficacy in complex spaghetti meals on postprandial glucose and C-peptide levels in healthy control and non-insulin-dependent diabetes mellitus subjects.

The effects of guar incorporated into a complex spaghetti meal on the glycaemic response in 11 healthy and 6 non-insulin dependent diabetic (NIDDM) subjects was studied. To this end, subjects consumed spaghetti made of either Triticum aestivum or Triticum durum wheat with or without 20 g% guar, as part of a complex meal containing 27% fat, 19% protein and 51% carbohydrate. In both the healthy as well as the NIDDM subjects the incremental integrated postprandial glucose and C-peptide responses after ingestion of a guar spaghetti meal were not different from the values found after a spaghetti meal without guar. In NIDDM subjects the incremental glucose and C-peptide levels were lower at 60 and 90 min and 90 and 150 min respectively after ingestion of guar aestivum spaghetti. Our negative results of effects of guar on postprandial glucose values may be explained by the presence of normal quantities of fat and protein in the meal and imply that addition of dietary fibre to a complex meal is not useful in the dietary management of NIDDM.

Adolescent↗
PubMed1986

Classification of brain-stem auditory evoked potentials by syntactic methods.

A syntactic pattern recognition procedure for classification of brain-stem auditory evoked potential (BSAEP) is presented. A pre-processing stage of zero-phase bandpass filtering enhances the peaks and suppresses the noise. A finite-state grammar was designed to identify the peaks. Attributes of the peaks (latencies and amplitudes) that are identified are checked for their acceptability. A training run on 70 subjects of known diagnosis was performed to fine-tune the system and build up necessary acceptance criteria. Peak latency differences are used for the classification rather than absolute peak latencies. Acceptance criteria for peak latency differences were empirically optimized. A data base of normal BSAEPs, created during the training run, was updated and used during the test run. Test of the classifier using 60 subjects yielded a classification accuracy of 83%. The classifier has acceptable accuracy and can be modified for other evoked potentials such as visual and somatosensory by establishing relevant attribute tables.

Brain Stem↗