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Biomedical subjects

H Wetzel

Publications and source records attributed to H Wetzel.

At least 73 records · Page 4Linked to original sources
PubMed1988

Improving depression severity assessment--I. Reliability, internal validity and sensitivity to change of three observer depression scales.

The Hamilton Depression Scale (HAMD) is the most commonly used scale for depression severity assessment and for antidepressant treatment evaluation. Alternative scales have been proposed by Bech and Rafaelsen (BRMS) and by Montgomery and Asberg (MADRS) to try to overcome the shortcomings of HAMD: they are based on different concepts of severity and different scaling procedures. Comparisons with respect to reliability, validity and ability to detect change have been performed using these scales in different samples. The BRMS proved superior. This result makes it necessary to question the usual procedure of testing the efficacy of antidepressants by means of HAMD alone. Problems in defining the severity of depression and in testing the validity of severity scales are discussed.

Adult↗
PubMed1987

Stupor and affective state: alleviation of psychomotor disturbances by lorazepam and recurrence of symptoms after Ro 15-1788.

In a single patient suffering from a major depressive episode with melancholia (DSM-III), both severe psychomotor symptoms, such as stupor and mutism, and mood disturbances could be abolished completely and promptly by administration of the benzodiazepine lorazepam. Remission of symptoms was entirely and immediately reversed by the benzodiazepine antagonist Ro 15-1788. These drug effects were constantly reproducible. Possible mechanisms of action and the influence of GABAergic neurotransmission on affective and psychomotor state are discussed.

Adult↗
PubMed1980

[Contamination of Baltic Sea fish with polychlorinated biphenyls].

Using a reaction gas chromatographic method, the authors determined the PCB contents of important fish species from three major fishing-grounds in the Baltic sea. They found that the PCB contents had but insignificantly changed in the period 1975--1979. Due to the simultaneous considerable reduction in total DDT content, there is a drift in the PCB/total DDT ratio. The causes of regional and seasonal variations are discussed.

Animals↗
PubMed1980

The use of freeze-dried blood in the membrane feeding of tsetse flies (Glossina p. palpalis, Diptera: Glossinidae).

Rearing of tsetse flies using membrane feeding became a method of routine during recent years. HOwever, the use of blood does require donor animals. Now, for the first time, a technique has been developed using freeze-dried blood as nutrient for Glossina p. palpalis. This report contains an account of the experiments carried out in obtaining a freeze-dried blood product. Initially, fresh bovine blood was processed prior to freeze-drying. It was later reconstituted with distilled water and the osmolarity adjusted to that of fresh blood. ATP was necessary for optimal blood uptake and the addition of albumin increased the weights of puparia. A colony of flies was reared for more than two years by feeding the flies with this reconstituted blood formulation. Later, in a modified freeze-drying programme the processing of the blood prior to drying was eliminated. The addition of ATP was still required, but the quality of the product was not improved anymore by enrichment with albumin, plasma or serum. In comparisons between freeze-dried blood, fresh blood and in vivo feeding of tsetse flies, no differences were found, except the puparial weights were considerably higher in the colony fed on freeze-dried blood than those of the fresh blood colony. This membrane feeding technique eliminates the dependence on blood donor animals for rearing of tsetse flies and can be recommended for breeding colonies in Africa.

Adenosine Triphosphate↗
PubMed1979

[Effect of bacterial infections and antibiotics on tsetse flies (Diptera, Glossinidae) (author's transl)].

The membrane feeding technique (in vitro feeding) used for the rearing of tsetse flies has advantages over the conventional method of feeding the flies on host animals. However, as long as blood remains the sole source of tsetse fly nutrition, the risk remains of blood being contaminated during collection, storage or feeding with bacteria pathogenic to the flies. The resulting high mortality of the tsetse flies endangers the success of this rearing. The experiments described here have shown that Glossina m. morsitans Westw. are more sensitive to Pseudomonas aeruginosa than G. p. palpalis Rob.-Desv. Rearing experiments over several years have confirmed this finding in that the latter species has never been threatened by high bacterial-induced mortality, whereas in 1973-74, due to contamination of the in vitro fed blood, a population of G. m. morsitans was difficult to colonize. The quantity of infected blood intake (14 to 70 mg) had no influence on the survival rate. However, when flies were infected once with Pseudomonas aeruginosa (dilution stage of 10(-3)), the organisms were eliminated after only nine days in living G. p. palpalis, but after 14 days in living G. m. morsitans. Females were infected at different stages of pregnancy but the same bacteria were not isolated in any puparia. Therefore, transmission of the bacteria to larvae growing in the uterus could not be demonstrated. All antibiotics used, to which bacteria isolated from tsetse flies in the laboratory were sensitive, caused a reduction in productivity. Parental females as well as females which emerged from larvae deposited by these flies (= F1-generation) 6 days after the administration of the drug to the pregnant females showed a similar loss in productivity. This corresponds with a degeneration of mesenteric symbionts. The most successful way to cope with bacterial infection in the membrane feeding technique in the rearing of tsetse flies has proved to be prophylactic measures, i.e. sterile membranes, sterile underlying aluminium trays and sterile blood. The methods employed at this laboratory, where up to 20 000 flies are being fed daily through membranes, have prevented dangerous bacterial infections in both species.

Animals↗
PubMed1978

The use of deep frozen, stored bovine blood for in vitro feeding of tsetse flies.

A method of blood preparation is described which resulted in the successful rearing of Glossina p. palpalis with in vitro feeding. Cells of defibrinated bovine blood were washed in 0.89% NaCl solution prior to deep-freezing. Cells and serum were stored (--28 degrees C) for up to four months. For feeding, both components were mixed in the volumetric proportion 1 : 1. Adenosine triphosphate was added at a concentration of 10-3 M to stimulate uptake of blood. Survival rate and mean weight of puparia remained constant over three generations while productivity increased.

Adenosine Triphosphate↗