A Palm-Sized Cryoprobe System With a Built-In Thermocouple and Its Application in an Animal Model of Epilepsy.

OBJECTIVE: The purpose of this study is to propose a palm-sized cryoprobe system with a built-in thermocouple (TC) for highly accurate and sensitive temperature measurements, and to verify the effectiveness of the system. METHODS: Conventional cryoprobe systems based on the boiling effect of a refrigerant have triple coaxial tubes. In the proposed system, the outer and middle coaxial tubes are made of two different metals that are welded only at the probe tip, thereby forming a TC. The thermoelectric properties of the built-in TC and measurement accuracy were investigated in agar in a constant-temperature chamber. The system was also applied in a penicillin G-induced rat brain epilepsy model. RESULTS: We verified that the built-in TC has appropriate thermoelectric properties and that the system more accurately and sensitively measured transient temperature changes at the probe tip wall compared to conventional systems, showing the cooling performance of the system. In the rat model, epileptiform activities disappeared on freezing, and reliable cell necrosis was achieved at an end temperature of -45.2 ± 1.6 °C. CONCLUSIONS: The proposed system is suitable for reliable cryosurgery. SIGNIFICANCE: The system is probably to be valuable for clarifying the relationship between freezing temperature and cell necrosis in vivo.

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.

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

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 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.

Contents of various elements in the organs of seabirds killed by an oil spill around Tsushima Island, Japan.

Twenty nine oil-soaked birds were collected from around the Coast of Tsushima Island. The contents of eight elements in the livers and kidneys of the birds were investigated. Statistically higher concentrations of vanadium and thallium in the liver and of titanium in the kidney were found in the birds that were found dead compared with those that died after rescued. A significant correlation (r=0.695, P<0.01) was observed only for the molybdenum content between the kidneys and livers from the birds found dead. Although the controls of the eight elements of birds investigated in the present study remain unexplained, some of lower concentration in rescued birds can be blamed on a decrease in food intake of birds. The relation between oil contamination and concentration of elements need to be further explored.

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

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.