Hiroshi Kajigaya

Metastatic melanoma appearing to originate from the beak of a racing pigeon (Columba livia).

Abstract A 12-year-old male pigeon (Columba livia) was reported to have a small lesion on the lower beak, which was diagnosed as malignant melanoma. After surgery to remove it, the general condition of the bird worsened and the bird died. Post mortem examination revealed gross, black-colored lesions in the liver, kidney, spleen, and femur bone marrow. Lesions were not found in the adrenals. Histopathologically, the neoplastic cells had a large amount of melanin pigment and showed severe anisokaryosis and prominent nucleoli. Mitotic activity was infrequent but varied considerably where it was observed.

Tetragomphius melis Infection of the Pancreas in Japanese Badger (Meles meles anakuma)

Hisashi Yoshimura, Yoko Matsuda, Masami Yamamoto, Tomohiko Endo, Hiroshi Kajigaya, Toshihiro Tokiwa, Toshiyuki Ishiwata and Shinji Kamiya Division of Physiological Pathology, Department of Applied Science, School of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University Department of Pathology, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology Division of Conservation Biology, Department of Applied Science, School of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University Division of Pathobiological Analysis, Department of Veterinary Pathobiology, School of Veterinary Medicine, Nippon Veterinary and Life Science University Department of Integrated Diagnostic Pathology, Graduate School of Medicine, Nippon Medical School Division of Animal Higher Function, Department of Applied Science, School of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University

The Palm-Sized Cryoprobe System Based on Refrigerant Expansion and Boiling and Its Application to an Animal Model of Epilepsy

Goal: The purpose of this study is to propose the palm-sized cryoprobe system based on a new concept and to suggest that the freezing technique could be used for treatment of epilepsy. Methods: We propose herein a cryoprobe system based on the boiling effect that uses a specific refrigerants with a boiling point higher than that of liquid nitrogen yet low enough to result in cell necrosis. To evaluate and verify the effectiveness of the proposed system, cooling characteristics are investigated in agar. In addition, the system is applied to a Wistar rat brain-model, in which the epileptic activities are induced in advance by a potent epileptogenic substance. Results: The design concept yielded the following benefits: 1) the selected refrigerant promotes sealing in the tank; 2) the tank can be made as compact as possible, limited only by the volume required for the refrigerant; 3) because the tank and probe units can be separated by a nonconducting, flexible, and high-pressure tube, the tank unit can be manipulated without disturbing the probe tip with mechanical vibrations and electrical noise. Although the agar experiments, we verified that the proposed system can uniquely and reproducibly create an ice ball. Moreover, in the rat experiments in vivo, it was confirmed that penicillin G-induced epileptic activities disappeared on freezing with the proposed system. Conclusions: The palm-sized system has desired characteristics and can apply for an animal model of epilepsy. Significance: Results of in vivo experiments suggest that cryosurgery may be an effective treatment for epilepsy.

TERATOMA OF THE OVARY IN A FREE-RANGING JAPANESE RACCOON DOG (NYCTEREUTES PROCYONOIDES VIVERRINUS)

Abstract A young adult, female, free-ranging Japanese raccoon dog (Nyctereutes procyonoides viverrinus) with scabies infection was found dead as a result of traumatic injuries presumed to reflect vehicular trauma. Necropsy showed a large solid mass located on the left ovarian region, occupying a third of the abdominal cavity. Histologically, the mass contained complex tissues derived from three germinal layers, with areas of cuboidal or columnar epithelium, keratinized squamous epithelium, bone, cartilage, and adipose tissue. This paper presents the first morphologic description of ovarian teratoma in a raccoon dog.

The Number of Louse Eggs on Wild Japanese Macaques (Macaca fuscata) Varies with Age, but Not with Sex or Season

During grooming, primates remove harmful ectoparasites, such as ticks and lice, and there is direct evidence for a health benefit of tick removal. Grooming behaviors differ among primates with respect to age and sex. Moreover, the number of ectoparasite may exhibit seasonal variation. Therefore the number of ectoparasites on a host may vary with effects, host age and sex, and season. However, these effects have not been a focus of louse infestation studies of primates. Grooming in Japanese macaques is related to sex and age, with developmental changes in behavior corresponding to the timing of tooth eruption. Moreover, behavioral data for Japanese macaques suggest that lice load may differ with the season. Thus, we examined whether the number of louse eggs varies according to host macaque sex, age, and season, and whether it changes in response to tooth eruption. We counted unhatched and hatched eggs attached to the hair on six 1-cm2 areas on the left wrist skin of culled macaques, using a stereoscopic microscope. We sampled five winter coats and three summer coats for each age class: infant, juvenile, adolescent, and adult. The number of unhatched and hatched eggs was related to age, but not to sex and season. There were significant differences in the number of unhatched eggs between infants and adults, juveniles and adults, and adolescents and adults. There were also significant differences in the number of hatched eggs between infants and adults, juveniles and adults, adolescents and adults. Tooth eruption did not influence the number of louse eggs. These results suggest that researchers should consider the age of host animals when assessing the relationship between grooming and ectoparasites.

Structural Changes in the Ovaries and Oviducts of the Green Iguana (Iguana iguana) Based on Developmental Stage and Reproductive Cycle

Abstract This report represents an investigation of the anatomical and histopathological structures associated with the female reproductive organs of Iguana iguana. The gross anatomy and histology of the ovary and oviduct of I. iguana were compared between immature and mature stages, and at different times in the estrous cycle. Although the structure of the reproductive organs of I. iguana was similar to historic descriptions, there were significant morphologic differences depending on the growth stage and phase of the reproductive cycle. Our results provide basic information related to the occurrence of ovarian and oviductal disease, which can be used when interpreting pathologic changes of the reproductive tract of female I. iguana.