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Biomedical subjects

G de Groot

Publications and source records attributed to G de Groot.

88 records · Page 5Linked to original sources
PubMed1983

A portable lightweight Douglas bag instrument for use during various types of exercise.

A construction outline of lightweight portable equipment for VO2 measurements by the Douglas bag method is given. The equipment consists of three separate units: an inspiration-expiration valve, a switch directing the expiratory flow, and a disconnectable bag with stopcock. The ease of operation assures good reproducibility of the results. Experiences during maximal speed skating are described. Use of the equipment demands only simple operations by the subject, which do not interfere with the exercise.

Adult↗
PubMed1982

Physical work capacity and daily physical activities of handicapped and non-handicapped children.

In this study physical work capacity, mechanical efficiency on the bicycle ergometer and daily physical activities were compared between 24 physically handicapped and 24 non-handicapped children. As a measure of mechanical efficiency and physical work capacity, the oxygen uptake per kg body weight at 0.5 watt . kg-1 and oxygen uptake per kg body weight at a heart rate of 150 beats . min-1 were used. The daily physical activities were recorded during a 24-h period by means of a scoring list. The load imposed by the daily physical activities was investigated by registration of heart rate. The mean value of the physical work capacity of the group of handicapped children was found to be lower compared with the non-handicapped children. The mechanical efficiency of 7 of the 24 handicapped children was lower when compared with the mechanical efficiency of 23 of the 24 non-handicapped children. A significant correlation between mechanical efficiency and nature of the handicap (spastic hemi-, di-, tetraplegic) was found (p less than 0.05). During light daily physical activities the handicapped children showed the same mean heart rate as the non-handicapped children, but the mean heart rate during heavy daily physical activities was lower for the handicapped group than for the non-handicapped group. The non-handicapped children spent more time in physical activities with relatively high heart rates. From the results obtained of oxygen uptake and heart rate measurements it is to be expected that non-handicapped children are able to maintain a higher state of training by means of their daily physical activities than are handicapped children.

Activities of Daily Living↗
PubMed1981

Buformin concentrations in a case of fatal lactic acidosis.

A fatal case of lactic acidosis in a 84 year old diabetic woman taking buformin is reported. Buformin concentrations in serum, other body fluids and tissues were measured by gas chromatography. Serum buformin concentration at admission was 5.5 mg/l. Postmortem concentrations were: in serum 3.2 mg/l; in lung 2.8 mg/kg wet weight; in heart 3.0 mg/kg; in pericardial fluid 3.5 mg/l; in liver 5.2 mg/kg; in bile 6.3 mg/l; and in kidney 98 mg/kg.

Acidosis↗
PubMed1981

Development of hypertension in spontaneously hypertensive rats after gonadectomy: effects of secobarbital anesthesia on the blood pressure.

Male spontaneously hypertensive rats (SHR) were gonadectomized at an age of 5 weeks. Systolic blood pressure and heart rate were measured up till an age of 12 weeks in trained unanesthetized rats. The development of the hypertension and heart rate were not significantly affected by removal of the testes and epididymis or removal of the testes only. Kidney, adrenal and thymus weight did differ from the values in sham-operated rats. After the administration of secobarbital sodium, however, a significant lower blood pressure had been observed in gonadectomized rats compared with sham-operated rats. Significantly higher levels of secobarbital were detected in plasma and brain of gonadectomized SHR. It is concluded that gonadectomy does not effect blood pressure of SHR and that the previously reported retardation of development of hypertension in gonadectomized SHR is caused by the different effect of anesthesia on blood pressure of gonadectomized and sham-operated rats.

Animals↗
PubMed1979

Chloral hydrate poisoning: its mechanism and therapy.

Chloral hydrate is a dangerous hypnotic drug to prescribe. Lethal dose can be a small as 4 gm. Nowadays the effects on the circulatory system are most dangerous. Which metabolite is responsible remains to be investigated. Haemoperfusion seems to be best method of lowering plasma levels of the metabolites, although the clearance of trichloroacetic acid is considered lower than of trichloroethanol.

Adult↗
PubMed1979

An evaluation of the use of hemoperfusion in acute poisoning.

We considered the use of hemoperfusion in the treatment of severe intoxications frequently seen in the Netherlands, primarily involving barbiturates and especially Vesparax (a combination of secobarbital, brallobarbital and hydroxyzine HCl) overdoses. In about 60% of the cases in which hemoperfusion seemed indicated, at least one barbiturate was involved; in about 20%, a Vesparax poisoning was found. From the obtained results it has been proven that for an adapted evaluation of hemoperfusion, in most cases it is not sufficient to determine merely the pre- and post-perfusion plasma levels, but also plasma levels have to be monitored during perfusion at the in- and out-let of the hemoperfusion column. Using these data, clearances and the total amount of drug removed were calculated. A comparison has been made with the elimination by forced diuresis. In some cases plasma elimination half-life values during and after perfusion have been computed and compared.

Adult↗
PubMed1976

Determination of lorazepam in plasma by electron capture GLC.

A method is described for the determination of lorazepam plasma levels involving extraction from the sample and analysis of the intact lorazepam by electron capture gas-liquid chromatography. Using mass spectrometry it is demonstrated, that lorazepam shows a thermal rearrangement under gas chromatographic conditions. The limit of detection is 0.01 mg/l and the assay shows a linearity from 0.01-0.80 mg lorazepam per liter of plasma.

Anti-Anxiety Agents↗
PubMedDate not supplied

A simple enzymic digestion procedure of intact tissue samples in pharmacokinetic drug analysis.

A simple procedure is described for the enzymic digestion of intact solid tissue samples. The samples are digested in an enzyme suspension containing collagenase and subtilisin Carlsberg without additional grinding or homogenizing. Bacterial growth during digestion is reduced by addition of an antibiotic solution. The resulting digests contain only very small tissue fragments. The total digestion is carried out at physiological conditions of temperature and pH, which makes the procedure suitable for inclusion in extraction procedures in a broad pH range. Since a minimum of sample manipulation is required, the procedure can be appropriately included in pharmacokinetic studies in which large series of samples are involved.

Anti-Bacterial Agents↗
PubMedDate not supplied

A rapid, simple, and reliable technique for preparation of antisera against idiotypes of homogeneous immunoglobulins.

One-step immunization of guinea pigs with homogeneous immunoglobulins partly purified by micro-agar electrophoresis represents a rapid and reliable microtechnique for the preparation of antisera against the idiotype of the homogeneous immunoglobulins. Testing of these antisera by immunodiffusion techniques requires agar plates containing 3% polyethyleneglycol 6000.

Animals↗
PubMedDate not supplied

Validation of spontaneous morphine withdrawal symptoms in rats.

Spontaneous morphine withdrawal has been studied in rats after induction of dependence using administration of morphine via the food (+/- 160 mg/kg/day on the basis of body weight). In the present paper, the decrease of the nocturnal locomotor activity and of food intake were validated as real morphine withdrawal symptoms. During the withdrawal phase, morphine was readministered either by subcutaneous injection of morphine or admixed in the food. Subcutaneous administration resulted in short-lasting enhancements (of 50%) of the locomotor activity (peak effects) followed by a decrease of 50%, while food intake and loss of body weight were hardly affected. Administration via the food resulted in a dose-dependent reduction of the decrease of the nocturnal locomotor activity, the decrease in food intake and the loss of body weight. Chronic naloxone infusion (0.03 or 0.1 mg/kg/hr) via osmotic minipumps appeared to have similar effects on locomotor activity, food intake and body weight, compared with spontaneous withdrawal of morphine. However, the recovery to normal values appeared to occur faster after naloxone infusion. It is concluded that the observed withdrawal symptoms, i.e. decrease of the locomotor activity, decrease of food intake and loss of body weight, can be interpreted as real withdrawal symptoms not caused by additional manipulations occurring in the course of the experiments.

Administration, Oral↗