Ventricular tachycardia initiated solely by reduced pacing rate during routine pacemaker follow-up

Ventricular arrhythmias during a pacemaker follow-up have been previously reported, usually in conjunction with temporary asynchronous stimulation of a demand pacemaker through magnet application or by increased myocardial excitability, for example, following a myocardial infarction. The subject of this report, an 82-year-old pacemaker patient, had been VVI-paced without problems for the past 11 years. As an aid in determining the sensing threshold, the pacemaker lower rate was reduced from 70 to 40 beats/min. A ventricular tachycardia of 240 beats/min was induced, most likely following short-long cycles; syncope resulted. To our knowledge, this is the first report of induction of a ventricular tachycardia during pacemaker follow-up solely by reduction of pacing rate and not by asynchronous pacing. This case demonstrates an additional potential risk associated with pacemaker rate manipulation during pacemaker follow-up.

[Performance of broiler chickens and quality of litter in various housing conditions (stocking density)]

In the present study the influence of a reduced stocking density on body weight, feed and water intake as well as the dry matter and nitrogen-centent (N) of bedding was examined in 3 fattening periods (2 x conventional closed stable, each 36 days, 1 x Louisiana stable, 40 days). In the controlls (stocking density 38 kg/m2) the broilers achieved a mean slaughter weight of 1497, 1411 and 1681 g, under experimental conditions (stocking density on average 33 kg/m2) the compareable figures were 1555, 1431 and 1793 g. Feed conversion ratios were better and the mortality during the fattening periods were lower in groups with reduced stocking density than in the controlls. There was no remarkable improvement of litter quality during the fattening periods in dependence on reduced stocking density. The dry matter content of litter decreased to 60%. At end of fattening the bedding contained 6-9g NH3-N, 7-17 g urea-N and 0,4-4 g uric acid-N/kg wet weight. The lowest uric acid values were found in the bedding samples from Louisiana stables. Effects of a reduced stocking density became obvious only in conventional closed stables by lowered NH3-N-concentrations. The stocking density had no influence on the distribution of the different fractions of NPN with regard to total N.

Response of rat colonic mucosa to a high fiber diet

Secreting lubricating mucins, colonic crypt goblet cells, contribute to the intestinal protection against mechanical challenge. After feeding germ-free (GF) and specific pathogen-free (SPF) AS/Ztm rats for 6 weeks, the proliferative response of colonic goblet to a commercial bulky diet (37.1% fiber) was compared to that of a standard diet. (4.4% fiber). An increased uptake of the high fiber diet by GF rats significantly augmented the capacity for mucin secretion as indicated by the amount and length of crypts, crypt cells and mature goblet cells. The response of SPF rats was limited to a crypt elongation, generated by more crypt cells. In both study groups, the goblet cell replication activity was similar to their controls. The increase in the mucin-secreting capacity, induced by a constant mechanical challenge, highly suggests an improved intestinal protection.

Response of the germfree rat colonic mucosa to dietary endotoxins

Suggestive to induce an immunoreactive response in the colon mucosa of germfree rats 3 diets, autoclaved or gamma-irradiated, respectively, were administered to groups of 30 days old GF Ztm:SPRD rats. Diets and rats were studied in parallel after a feeding period of 20 days. The microbiological controls confirmed the sterility of diets and animals. The aqueous suspensions of one diet displayed obviously dead yeast and Gram positive and negative bacteria, which consistently were evident in colonic cast preparations of animals fed with this diet. These findings apparently were not related to the pathohistological alterations, observed in hematoxilin-eosin stained colon sections. However, dietary endotoxin concentrations between 0.6 and 10 micrograms LPS/g corresponded with the endotoxin concentrations in feces (0.3 to 3.1 micrograms LPS/g wet weight) and in colonic tissue (0.01 to 0.6 microgram LPS/g wet weight). These endotoxins obviously mediated a dose-dependent immunoreactive response of the colonic mucosa: in parallel to the dietary endotoxin content, the cellular infiltrations ranged from single mononuclear cells to severe, cell mediated, mucosal alteration. GF rats, used as an experimental animal model for inflammatory disorders of the intestine obviously necessitate diets with low endotoxin concentrations.

[Animal nutrition for veterinarians--recent cases: yew poisoning in goats with lethal results as a result of improper disposition of hedge clippings]

Mini goats (n = 40) were kept in a paddock. During October hay and supplementary mixed feed were given in a addition to grass; water was available ad libitum. About 3 hours after a last control (at about 2 p.m.) 8 animals were found dead and further 3 in a moribund condition; 2 of them died within 2 hours and the last one during the following night. Branches of yew were found in the paddock, obviously wastes of a neighbored garden. Therefore an intoxication by Taxus sp. was suspected. For a further clarification the rumen contents of two died goats were investigated. The rumen contained 1190 and 1710 g ingesta, which were interspersed by visible leaves of Taxus and their fragments. The identification was ensured by control under a magnifier; also some leaves in an arrangement typical for male Taxus were observed. Taxus leaves in the 2 rumens were counted and in consideration of the fragments 2190 and 230 leaves per kg rumen content were estimated. Assuming a mean weight for Taxus leaves in autumn of 18.4 mg/leave (+/- 3.9, n = 50, fresh cut leaves) a consumption of 2.4 and 0.4 g Taxus leaves/kg body weight is derived. An overview in literature is given and documents a high number of cases in horses and ruminants. Important by forensic point of view is the endangering of animals by mistakes in keeping conditions, as pasturing meadows with neighbouring yews, or the wrong handling of hedge cut as well as the evidence of Taxus leaves in the stomach to ensure diagnosis.

[Observations of the liver copper content in sheep in northwest Germany]

Samples of liver tissue from sheep (n = 231), which were send to the Institute on Animal Nutrition, School of Veterinary Sciences Hannover, were analyzed for copper; the results were evaluated in reference to animal's age and race. In tissue of young sheep (up to 4 weeks) the copper concentration was about 250 (56-770) mg/kg dry matter (DM); values < 120 as well as > 300 mg/kg DM were observed in few cases only. From 198 data of adult sheep 28% suggested a copper deficiency (< 50 mg/kg DM), while 21% were the result (> 500 mg/kg DM) of a critically elevated copper intake. Sheep of the typical heath race presented the main part of those affected by copper deficiency; the races merino and Texel dominated in the group with elevated copper concentrations in liver tissue.