Biomedical subjects

R Wenkel

Publications and source records attributed to R Wenkel.

6 recordsLinked to original sources

PubMed2005

Indicators for post-surgery recovery in Mongolian gerbils (Meriones unguiculatus).

Telemetric investigations of various parameters are widely used to estimate an animal's state. However, the implantation of the transmitters includes anaesthesia and surgery and has short and longer lasting impacts on the studied object. The aim of the present paper was to evaluate these effects in Mongolian gerbils, namely the hypothermia caused by the anaesthetic and the enduring disturbance of daily rhythmicity until complete recovery. The surgery associated with the implantation of the transmitters differed both in severity and type of anaesthesia. Whereas normal values of body temperature were restored within hours, restoration of daily rhythm required several days, depending on the severity of the surgical procedure. Also, the sensitivity of the body temperature to activity changes was different until the rhythms were re-established. A method based on the rhythm magnitude and shape was proposed to estimate the time until complete recovery of the animals.

Anesthetics, Inhalation↗

PubMed1998

[Urinary calculi in small and other animals--a retrospective study of the years 1980-1989].

More than 500 uroliths from dogs, cats, minks, rabbits and 9 further animal species originating from various regions of former East Germany were analysed. The observations were made between 1980 and 1989 using X-ray diffraction and infrared spectroscopy. The urinary stones consisted of struvite, whewellite, weddellite, cystine, ammonium urate, brushite, whitlockite, hydroxyapatite or carbonate-apatite, calcium carbonate, silicon dioxide and organic matrix stones. In dogs, the most frequent types were struvite and apatite concrements, followed by calcium oxalate and cystine uroliths. Among the diseased animals poodles, dachshunds and terriers ranked first. In the analysed material from cats apatite and struvite predominated. With few exceptions, minks formed struvite uroliths only. The analysed calculi from rabbits consisted principally of calcium phosphate or calcium carbonate concrements. The present analysis has been compared with results of former studies, differences are discussed.

Animals↗

PubMed1992

Hippocampal mossy fiber distribution does not correlate with two-way active avoidance performance in backcross lines derived from inbred mouse strains DBA/2 and C3H.

To elucidate the relation of genetically induced variations in two-way active avoidance performance and the extent of the hippocampal infra/intrapyramidal mossy fiber system (IIP-Mf) in inbred mouse strains DBA/2 (high performance, small IIP-Mf) and C3H (low performance, large IIP-Mf) we investigated a backcross line containing the DBA/2-derived genetic determinants for high avoidance performance in a C3H background. In the seventh backcross generation variations in performance analogous to the original strains were observed whereas the extent of mossy fibers was nearly homogeneous. This result suggests that both variables are determined by separate genetic factors at least in these strains and that differences in mossy fiber distribution are not an essential prerequisite for different active avoidance performance.

Afferent Pathways↗

PubMed1988

[Fluctuations in neuronal activity and sexual dimorphism in the medial preoptic nucleus of the hypothalamus during postnatal development of the rat].

The medial preoptic nucleus of the hypothalamus of the rat is characterized by a sexual dimorphism of one of its substructures, the "sexually dimorphic nucleus of the preoptic area (SDN-POA)" (Gorski et al. 1980), which becomes light microscopically visible at lower magnification. The SDN-POA, showing up as a concentration of perikarya, is principally larger in males than in females. Furthermore, the sexual dimorphism of the medial preoptic nucleus is reflected in temporary significant differences of the nuclear size of its neurons, which again are discussed as the correlate of differences of the neuronal activities. Karyovolumetrically verified variations of activities of the medial preoptic nucleus were observed during continuous studies at totally 180 rats (90 females and 90 males), aged between 5 (P 5) and 60 (P 60) days. These are already known in other cerebral structures and also typical for the comparably studied neurons of the granular layer. They are especially distinct during the first 3-4 days of the postnatal development and characterized by larger amplitudes in male than in female rats. Typical are peaks of activities at P 10 and P 20 as also--especially in males--at P 45. The variations of the neuronal activities are discussed as summarizing reflection of gene activities, correlated with cytological processes of development and differentiation, which again are superimposed by a total of age related and sex specific performances of the Nucleus-preopticus-medialis-neurons. The karyovolumetrically verified sexual dimorphism of the medial preoptic nucleus, appearing as a differently developed SDN-POA, is a reflection of the sex specific morphological-functional differentiation of the central nervous system. A more for-reaching, specifying discussion of the results, complicated by the functional complexity of the medial preoptic nucleus, will be obtained by directed experimental studies.

Action Potentials↗

PubMed1982

[Automatic semicontinuous peritoneal dialysis with volumetric cycle control].

An automatic peritoneal dialyser constructed by the authors is presented. It works on the principle of so-called semi-continuous peritoneal dialysis. Only 200 ml of dialysate are exchanged per cycle after the peritoneum has been filled. Whereas with the time control used by Di Paolo the outflow can fluctuate considerably due to various disturbing factors, volume control makes it possible to balance inflow and outflow precisely. The advantages of this procedure of peritoneal dialysis are that it functions automatically and that it therefore requires little attention from staff.

Humans↗

PubMed1981

[A simple method for the reinfusion of ascitic fluid in hemodialysis patients].

A simple method for the ascites reinfusion in patients undergoing chronic dialysis, which is easily to be performed using the dialysis apparatuses during the regular haemodialyses and scarcely needs expenditure. When an ascites derivation is indicated in patients undergoing haemodialysis should, in order to avoid a loss of protein, always a reinfusion of the ascites be performed.

Ascites↗