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Biomedical subjects

M de Vries

Publications and source records attributed to M de Vries.

At least 37 records · Page 2Linked to original sources
PubMed1996

Veterinary practice and occupational health. An epidemiological study of several professional groups of Dutch veterinarians. I. General physical examination and prevalence of allergy, lung function disorders, and bronchial hyperreactivity.

The prevalence of allergy, lung function disorders, and bronchial hyperreactivity was studied in 102 Dutch veterinarians, subdivided into five professional groups (predominantly working with either swine, cattle, poultry, companion animals, or as a non-practitioner). The mean age of the participants was 43 years; 6 participants were females. Twenty-two per cent of the participants were overweight, and relatively more non-practitioners than practitioners were overweight. Approximately 23% of the vets reported complaints of prolonged fatigue. The data suggest a relationship between complaints of prolonged fatigue and a more than average number of daily working hours. Only a small proportion of vets were sensitized against several allergens. There were no significant differences in prevalence of distinct lung function disorders or bronchial hyperreactivity between professional groups. It is hypothesized that the respiratory complaints (chronic coughing, chronic phlegm production, stuffed nose, sneezing) reported by the vets predominantly working in swine and/or poultry practice could be caused by irritation and/or inflammation of the first part of the trachea-bronchial tree that has no measurable and permanent consequences for changes in lung function or increased bronchial hyperreactivity. The results of a skin test against allergens and determination of allergen-specific IgE in blood indicated that the respiratory complaints were probably not related to allergy against the panel of allergens tested.

Adult↗
PubMed1996

Veterinary practice and occupational health. An epidemiological study of several professional groups of Dutch veterinarians. II. Peak expiratory flow variability, dust and endotoxin measurements, use of respiratory protection devices, and time distribution of professional activities.

Dust and endotoxin exposure was measured in the Spring and Autumn in 96 veterinary practitioners, subdivided in four professional groups ((predominantly working with either swine, cattle, poultry, or companion animals). Furthermore, peak expiratory flow (PEF) variability was measured four times a day over a week in Spring and Autumn in order to detect occupation-related respiratory disorders. The participants kept a log book in which they recorded their activities during these periods. Practitioners working with swine, cattle, or poultry had a significantly higher exposure to dust (+/- 5 times) and endotoxin (+/- 10 times) than companion animal practitioners. PEF variability measurements gave no indications for an increased prevalence of bronchial hyperreactivity related to occupational activities. Respiratory protective devices (RPD) were used selectively. Only a small proportion of the practitioners used them at any time when entering a animal confinement building. Swine and cattle practitioners worked for approximately 3.6 hours per day in animal buildings, whereas poultry practitioners worked in the environment of poultry buildings for approximately 2.8 hours per day.

Animals↗
PubMed1995

Development and mapping of ten porcine microsatellite markers.

Thirty (TG)n microsatellite clones were isolated from a pig genomic library, sequenced, and tested for their suitability to detect polymorphism on a panel of animals by means of the polymerase chain reaction. Ten of these clones were developed into suitable markers and subsequently segregation of these markers was determined in the five PiGMaP reference pedigrees. A linkage analysis was performed on these 10 microsatellites together with 365 other loci that have been typed on these reference families. Eight of the microsatellites have been mapped to eight different linkage groups that have been previously assigned to different chromosomes (chromosomes 1, 6, 7, 9, 14, 15, 17 and 18). Of the remaining two markers, one is X-linked and the other shows no linkage. The number of alleles detected by these microsatellites, in the reference pedigrees, varied from six to sixteen and the heterozygosity varied from 42 to 85% in the 26 unrelated founder animals of these reference pedigrees.

Animals↗
PubMed1993

Sulphation and glucuronidation of ritodrine in human foetal and adult tissues.

Ritodrine is a beta 2-adrenoceptor agonist used for the management of preterm labour. It is inactivated by conjugation with sulphate and glucuronic acid. There is more ritodrine sulphate than ritodrine glucuronide in urine from the newborn whereas equal amounts of ritodrine glucuronide and sulphate are excreted in maternal urine [Clin. Pharmacol. Ther 44, 634-641, 1988]. We show that, in the mid-gestational human fetal liver, ritodrine sulphotransferase is well expressed, whereas the glucuronidation of ritodrine is little developed compared to the adult liver. The average sulphotransferase activity was 308 pmol.min-1 per mg protein in fetal (N = 48) and 145 pmol.min-1 per mg protein in adult (N = 32) liver. The rates of ritodrine sulphation in fetal gut, lung and kidney were higher than in the corresponding adult tissues. The development and tissue distribution patterns of ritodrine sulphotransferase are consistent with those of dopamine sulphotransferase. Ritodrine and dopamine are sulphated by thermolabile enzymes. The activity of glucuronyl transferase was measurable in only 5 of the 48 foetal livers assayed, and in those in which could be assayed, the average activity was 44.6 pmol.min-1 per mg protein, one-tenth of that in adult livers (524 pmol.min-1 per mg protein).

Adult↗
PubMed1992

Calibrating microwave-incubation times for droplet immunostaining: reversible Thermo-Paint as a low cost alternative.

Reversible Thermo-Paint R50 (Manufactured by Thermographic Measurements, Ltd., Burton, UK and imported in The Netherlands by Blanken Controls, Loenen (Vel.)) has a yellow colour that changes to orange when a temperature of 50 degrees C is reached. Microscopical glass slides can be painted with R50. Under the droplet on the painted slide an orange disk will appear at the moment the droplet has reached the temperature of 50 degrees C. This test provides us with information about how much energy per minute is available to be absorbed by that precisely defined "test droplet" using a certain setup of the microwave oven. The obtained data can be used to calibrate incubation times for various microwave ovens. The results explain why, when short cycle times are used, immunostaining is highly reproducible.

Calibration↗
PubMed1991

Simultaneous measurement of serotonin and 5-hydroxyindoleacetic acid in rat brain using a liquid chromatographic method with electrochemical detection.

A simple and sensitive method for the simultaneous measurement of 5-hydroxytryptamine and its main metabolite 5-hydroxyindoleacetic acid in rat brain is described. Brain tissue samples were only deproteinated and, without further extraction, were injected directly onto a high-performance liquid chromatography column and detected electrochemically. The detection limit for 5-hydroxytryptamine and 5-hydroxyindoleacetic acid was 16 and 8 g per injection, respectively. Within 8 min, the total separation of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid is achieved. With this method over 100 analyses can be performed in a single working day. Brain samples from young and old, male and female Brown Norway rats were analysed for indoles by this method. The ratio 5-hydroxytryptamine 5-hydroxyindoleacetic acid, an index for serotonin turnover, showed significant differences between age groups and genders in the cortex, and a significant difference between genders in the hypothalamus.

Aging↗
PubMed1988

Cisplatin-induced changes of selenium levels and glutathione peroxidase activities in blood of testis tumor patients.

Haematocrit and glutathione peroxidase activity in blood, as well as selenium levels in blood, erythrocytes and plasma, were determined in 15 patients during four courses of cisplatin combination treatment for testicular teratoma. The haematocrit steadily declined, necessitating frequent blood transfusions during or after treatment. For patients without blood transfusions during treatment the reduction of the haematocrit averaged 40%. Glutathione peroxidase activity in blood declined also; for patients without blood transfusion the reduction was 30%, which is fully explained by the decrease of the haematocrit. The enzyme activity per volume of erythrocytes remained constant during the treatment. Erythrocyte selenium level did not change significantly, but plasma selenium levels of all patients dropped within each course of chemotherapy, and progressively with each subsequent course. Between cycles the levels were largely restored to almost normal values. These results may be explained by a decreasing availability of selenium in the body to maintain the normal plasma level, due to increased retention of cisplatin in tissues and subsequent alteration of selenium metabolism.

Adolescent↗