Image Analysis Using Nuclear Magnetic Resonance with 9.4 Tesla of Static Magnet Field

Magnetic resonance image (MRI) is characteristic of a fine spatial resolution compared with Computer tomography and Ultrasonic tomography. The intensity of the external static magnet field of MRI is important factor on the spatial resolution. The tomogram depend on the conditions of measurements and intensity of the external static magnetic field. Further more, difference of measurement conditions depends on tissues. We show measurement conditions of chest and abdomen and the principle of MRI

Insulative Adaptation to Cold and Absence of Circadian Body Temperature Rhythm in Afghan Pikas : Ochotona rufescens rufescens

The pika inhabiting cold climate and high mountains is thought to be adapted to its environment. The autonomic characteristics of the high body temperature, high metabolism and poor heat loss ability such as poor panting, small ear pinnae and absence of thermal salivation as well as the behavioral characteristics, i.e. living in burrows under the ground or in the shelter among rocks and hoarding grasses for food to survive winter have been reported. However, insulative cold defense in pikas have not been studied and the pika\u27s circadian activity rhythm remains controversial. In this study, the skin thickness and hairs length were histologically studied and the body temperature and locomotive activity were monitored in the freely moving pikas with a bio-telemetry system to clarify the pika\u27s circadian rhythm. The hairs in the pikas were longer than the rats and more dense and 2 times longer on the dorsal region than the ventral region, though the skin was thinner. 20 mm of the hair length of the pikas was estimated to provide 3 Clo of insulative property. In contrast with the robust nocturnal rhythms in the rabbits and the rats, neither diurnal nor nocturnal body temperature rhythm was observed in the pikas, except for a slight increase at dawn and dusk consistent with the previous field observations. The pika is considered to be adaptive to cold not only ecologically and autonomically but also due to the insulative cold defense mechanisms. Though further investigation should be done, the absence of circadian body temperature rhythm in the pika is quite unique and attractive for the research field of circadian rhythm

Haulage Methods in Different Areas of Nepal and the Health Condition of the Porters in Kathmandu

The complicated geographical features of Nepal make transport of goods difficult. People have to depend on human power even today, especially porters who use a number of different transport styles. The objectives of this study were to document (1) the characteristics of haulage methods in relation to the geographical conditions, and (2) the diurnal activities and health of porters in Kathmandu. The observed methods used by the porters in Nepal to carry loads were divided into four main classes: (1) on the top of the head, (2) by handcart, (3) in baskets on a yoke across the shoulders, and (4) on the back using a tumpline. The method of carrying a load on the back with a tumpline was most commonly observed, although this style might cause damage to the spinal vertebrae. The study of the diurnal activities and health condition of porters was limited to those in Kathmandu. For this purpose seven porters were interviewed orally. The results can be summarised as follows: (1) luggage of about 60kg to 110kg could be carried, (2) six of the seven porters habitually smoked tobacco and drank alcohol, (3) many porters wore cloth tightly twisted around their waist, and (4) complaints of severe neck pain were not made, but all porters complained of knee and/or back pains. The cervical and lumbar vertebrae of these porters were examined by roentgenological analysis, but no abnormal changes were observed

A Field Study of Telemetry-Recording of The Body Temperature in Wild Mongolian Pikas

The pika inhabiting in cold zone or in high mountains is thought to be adapted to cold as well as high-altitude environment. We have reported pika\u27s high body temperature (39.6℃), high metabolism and poor heat loss ability such as poor panting, small ear pinnae and lack of thermal salivation. In this study, we measured the body temperature of wild pikas (Ochotona daurica) with a telemetry device in their natural burrows in Mongolia. Two pikas captured at Undur Dov were implanted with transmitters in the abdominal cavity under anesthesia, and were returned to the own habitat. The mean body temperatures of the pikas were 39.65℃ and 39.96℃ though the data were limited to a short period of less than one day. The present results in wild pikas support pika\u27s high body temperature in our previous studies

Relationship between the Duration of Stay in Japan of Malaysian Subjects and the Suppression of Sweat Gland Sensitivity by lontophoretically Applied Acetylcholine

Tropical African and Thai Subjects regulate core temperature with less amount of sweat against heat compared to temperate Japanese subjects. Reduced sweating in tropical subjects was attributed to suppression of both central and peripheral sudomotor mechanisms. The objective of the study is to compare the local sweating response activated by acetycholine (ACh) applied iontophoretically among the Malaysians (n=12) of varying duration of stay in Japan. Based on their length of stay, Malaysian subjects were divided into 2 groups, MS (n=6) with a duration of stay of 3 to 15 months and ML (n=6) with 27 to 60 months. ACh, the primary transmitter for sudomotor innervation, was iontophoretically administered on the forearm. Sweating response elicited directly (DIR) and indirectly via axon reflex (AXR) were evaluated by quantitative sudomotor axon reflex test. Although the sweat onset time was tend to reduce with longer duration of stay among Malaysian subjects, there was no significant difference among the two groups. AXR (1), sweat volume elicited by axon reflex for 0-5 min was 0.96ﾂｱ0.11 mg/cm2 in MS and 1.40ﾂｱ0.23 mg/cm2 in ML. AXR(2), that for 6-11 min, was 1.09ﾂｱ0.13 mg/cm2 and 1.45ﾂｱ0.20 mg/cm2. DIR, sweat volume directly induced by ACh for 6-11 min, was 3.40ﾂｱ0.18 mg/cm2 and 3.96ﾂｱ0. 24 mg/cm2 in MS and ML , respectively. A slight positive correlation between DIR and the duration of stay in Japan was observed in Malaysian subjects, though not significant (p=0.14). From these results, suppressed neuroglandular response to ACh was confirmed in Malaysians. It is suggested that long-term heat-acclimatization acquired in tropical subjects may decay after immigration to temperate area

Thermobiological Characteristics of Pikas, Rabbits and Rats

Animals are provided by nature with biological defense mechanisms against the deleterious effects of the environment. Three different animal species: pikas, rabbits and rats were compared in their thermobiological characteristics. Results revealed significant dissimilarities of the characteristics of pikas from both rabbits and rats that they called morphologically and physiologically unique. Compared to the two, these animals have relatively high body temperature and absence of circadian rhythm in core body temperature. These probably explain the non-manifestation of thermal panting and salivation which are evidences of the absence of natural heat losing ability in these animals. Since 1975 up to the present blood glucose has never been studied in pikas. Thus, in this experiment, this substance was determined to explain some biochemical related peculiarities in these animals. Findings revealed a low blood glucose level in pika in contrast to the rats but relatively similar to that of the rabbits. Conclusively, pikas have peculiarities which enable them to exist in environments with low temperature. It seems that blood glucose does not bear any relationship with this physiological nature. The same characteristics make them different from Lagomorpha and other lower animals

Study on Mechanisms of Heat Acclimatization Due to Thermal Sweating : Comparison of Heat-tolerance between Japanese and Thai Subjects

Heat tolerance and sweat response to heat load of tropical subjects in Chiang Mai and temperate subjects in Nagasaki were compared under identical conditions. Male students in Chiang Mai (n=10) and in Nagasaki (n=10) volunteered for this study. The Thai subjects were a little shorter and slightly leaner than the Japanese. Heat load was applied on the legs by immersion into hot water (43℃) for 30 min in the room at 26.6℃ and 33%rh. Sublingual (oral) temperature was measured with a thermistor probe and local sweat rate was measured by the capacitance hygrometer-sweat capsule method. Change in oral temperature, sweat onset time and local sweat volume were compared between Japanese and Thai. Initial oral temperatures (36.76±0.11℃ in Japanese, 36.71±0.23℃ in Thai) were identical, and no sweat was observed before heat load. Mean sweat onset time (9.3±2.1 min chest in Japanese, 16.6±5.6 min chest in Thai) were significantly longer and local sweat volume (10.19±5.00 mg/cm^2, chest in Japanese, 1.39±0.91 mg/cm^2, chest in Thai) was significantly smaller in Thai subjects than Japanese, however, oral temperature (37.18±0.32℃) of Thai subjects was kept slightly lower than oral temperature (37.42±0.10℃) of Japanese even under a 30 min heat load. Sweat volume on the abdomen was larger than on the chest in 9 of 10 Thai subjects. On the contrary, sweat volume on the chest was larger than that on the abdomen in 7 of 10 Japanese subjects. These results suggest that heat tolerance of tropical subjects in due to a more efficient evaporative ability due to a greater heat loss brought about by their long term exposure to heat. Furthermore, the habituation phenomenon related to the reduction of thermoregulatory effector mechanisms were also considered so as to clarify the mechanisms of thermal acclimatization

Evaluation of the Applicability of Infrared and Thermistor-Thermometry in Thermophysiology Research

The accuracy and reliability of temperature measuring devices in thermal physiology research and clinical practice has been subject of various investigations. Research data have been conflicting in some cases. Further investigations are therefore needed to elucidate the reliability and sensitivity of these devices under different temperature settings. The aim of this study was to evaluate the reliability and sensitivity of the tympanic thermistor (TT), infrared tympanic thermometer (ITT) and oral thermistor (OT) in the detection of body temperature changes in adults exposed to heat load. A single set of three simultaneous temperatures i.e. oral, left and right tympanic membrane were measured. At rest, core temperature (Tc) measured by TT was 0.45℃ and+0.10～-0.12℃ (changed range) higher than that measured with OT and ITT respectively. At the end of 30min 43℃ water bath leg immersion, Tc measured by TT was 0.48℃ and 0.04℃ higher than that measured with OT and ITT. This showed that when subjects were exposed to heat load, there was no difference in Tc measured by TT and ITT, although both were significantly higher than that measured with OT. From these results, it might be thought that the sensitivity for Tc detection increased in the order tympanic thermistor>infrared thermometer>oral thermistor. Further-more, in addition to the merits of infrared thermometer, the hazards and difficulties of tympanic temperature measurement were discussed from the view of development of the various kinds of thermometers

Heat Loss Response Induced by Local Heating of Spinal Cord with Argon Laser

The parts of spinal cord were locally heated with an argon laser in order to induce the heat loss responses in rabbits. And the spinal cord touched with a guide tube for a glass fiber (0.4mm in diameter) was heated by the argon laser irradiation inside the guide tube. This local heating method is possible selectively to heat a part of spinal cord within length of implanted guide tube. The guide tube was implanted into the peridural space from lumbar vertebrae (L4/L5) to thoracic vertebra (Th7) of the rabbit in anesthesia. Two days after implantation of the guide tube, the lateral portion of spinal cord was locally heated in 10 mm sections. Then the heat loss responses such as increases in an ear skin temperature and a respiratory rate were induced by local heating of only 10 mm length in lumbar spinal cord. However, every 10 mm sections of spinal cord could not induce the marked heat loss responses when the spinal cord was locally heated in 10 mm sections