Anthelmintic treatment to eradicate cutaneous capillariasis in a colony of South African clawed frogs (Xenopus laevis).

The nematode Capillaria xenopodis (Pseudocapillaroides xenopi), a skin parasite of South African clawed frogs (Xenopus laevis), is quite common in laboratory animal facilities. It causes serious skin changes and may further lead to wasting and death of affected frogs. Various treatment protocols, using the anthelmintics ivermectin and levamisole, were successively tested for practicability of elimination of the parasite from a colony of clawed frogs. Nematodes were reduced below diagnostic levels by various methods of application of ivermectin (orally or by injection into the dorsal lymph sac, twice at intervals of 10 to 14 days). However, nematodes were found again in the treated animals 1 to 3 months later. Treatment by use of ivermectin-medicated tank water is not feasible due to its low water solubility. Elimination of the parasite was reliably achieved by use of levamisole-medicated tank water. Relapses were not seen during the 18-month posttreatment observation period. Levamisole concentration was 12 mg/L of water, with 4.17, 5.00, or 6.25 L of tank water/frog, and 50, 60, or 75 mg of levamisole available/frog, for at least 4 days, with treatments repeated after 10 to 14 days. Results were reproducible in two trials each with five tanks containing, in turn, four or five frogs each. A treatment trial carried out with a group of 20 adult frogs exposed to 12 mg of levamisole/L of tank water, but with only 2.5 L of tank water/frog (i.e., only 30 mg of levamisole available/animal), was not effective in eradicating the parasites. Not only the drug concentration, but also the amount of drug available per animal seems to be of importance. In contrast to thiabendazole, which is often reported in literature as treatment for cutaneous capillariasis, negative side effects were not observed with use of levamisole.

Hereditary compulsive self-mutillating behaviour in laboratory rabbits.

During the last few years an increasing number of cases of extensive automutilation has been observed in a rabbit breeding colony of Checkered crosses. Digits and pads of the front feet were traumatized. No other behavioural abnormalities or signs of disease were evident. Self-mutillation was seen both in stock, breeding and experimental animals, in rabbits kept singly in cages and in those housed in groups on the ground, in rabbits kept in different buildings and under the care of different staff members. This behavioural abnormality of Checkered crosses has also been observed in animals after being placed into other institutions or private homes. No evidence of an agent responsible for the occurrence of self-injury could be found with parasitological, mycological, histological, clinical or haematological examination. Twelve to 16 animals are affected yearly in a colony varying in size between 130 and 230 rabbits. Following complete healing, relapses occurred up to 3 times per year, on either the same or the opposite front foot. In the last 21 cases episodes of automutillation could be regularly interrupted with the dopamine antagonist, haloperidol. Similar signs of auto-mutillation were never seen in animals of another breeding line kept in the same building and under the same conditions nor in animals brought in from other breeding colonies. A relatively high coefficient of inbreeding can be presupposed in this 15-year-old breeding colony of Checkered crosses. A genetic predisposition for the behavioural anomaly described appears very likely.

Growth of Xenopus laevis under different laboratory rearing conditions.

Since the European frogs (Rana spp.) have fallen under the German endangered species regulation, Xenopus laevis (South African Clawed Frog) is being used increasingly in animal research and education. Optimal growth rates and homogeneity of groups have not necessarily been attained as little statistical analysis of growth data has been available. Following metamorphosis, an as yet not understood variability of growth is exhibited by X. laevis. In this study the effect of environmental factors on this variability was determined. Feeding, population density, background colouring, water temperature, the availability of hiding places, water level and water care were each examined separately. Development of body weight and body length were recorded. A definite correlation between the feeding programme, population density, cover and water care on the one hand and growth on the other were seen. Of lesser importance were water temperature, water level and background colouring. The observed variability of growth is assumed to also be of ethological origin.

[Transplantation of human renal adenocarcinoma tissue on the nude mouse (author's transl)]. / Transplantation von menschlichem nierenadenokarzinomgewebe auf die nackte maus.

Tissues of human renal cell carcinoma and of its lymph-node metastases were transplanted between the 1st and the 4th passage on 80 nu/nu mice. Growth of tumor was observed in all cases. Chromosomal analyses proved the tumor origin of the transplants. The primary tumor showed two histological patterns: a granular solid cell carcinoma and sarcomatoid elements. The lymph nodes showed only sarcomatoid tissue of the primary tumor. Light-and electron-microscopic examinations showed that the transplanted tumor contained only the sarcomatoid tissue of the original tumor. The solid carcinomatous tissue was not found and, therefore, probably not transplanted. Flow cytometric investigations of the primary tumor revealed two cell populations with a DNA content of 6 and 10.8 pg. Both cell colonies were also discovered in the transplanted tumors as well. The transplants of the primary tumors grew significantly slower than those of the lymph-node metastases. After an initial inert phase, the transplanted tumors grew more rapidly in the male than in the female animals. Neither hematogenous nor lymphatic metastases were observed. After local excision, recurrent tumor development was found in 80% of the experimental animals.

[Possibilities of cytostatic therapy in adenocarcinoma of the kidney. I. Influence of vinblastine on the growth of transplanted tumors]. / Möglichkeiten der zytostatischen therapie beim adenokarzinom der niere. I. Einfluss von vinblastin auf das wachstum transplantierter tumoren.

The effect of vinblastine sulfate on the acceptance and growth of a very malignant, human adenocarcinoma of the kidney (RCCI) on nude mice was investigated. Without any treatment, this tumor has an acceptance rate of 100%. Subcutaneously transplanted pieces of tumor, measuring 3 X 3 X 1 mm, commence to grow rapidly 1 week after transplantation and reach a diameter of approximately 2 cm, 6 weeks thereafter. Tumors with a diameter of approximately 2 cm, treated during 6 weeks with vinblastine (0.6 mg/kg/week), continued to grow during treatment and thereafter. However, when these growing, pretreated tumors were transplanted on new experimental animals, they either were not accepted by them or grew very slowly. When animals with tumor transplants were treated for 6 weeks with vinblastine (same schedule as above), beginning on the 1st day after transplantation, tumor growth was markedly retarded in every case, but only very seldom the tumor was not accepted.