The effect of adaptation to cold and re-adaptation to room temperature on the level of glutathione in rat tissues

1. Glutathione (GSH) was assayed in plasma, liver and IBAT in control (22±1°C) and cold adapted rats (45 days in 5±1°C), and in rats cold adapted and brought back to room temperature after 1, 3, 7 and 15 days.

2. Adaptation to the cold led to reduced GSH in the liver and plasma while the level in intrascapular brown adipose tissue (IBAT) was increased in comparison to controls.

3. On the first day of re-adaptation, plasma GSH was similar to the control level, as were hepatic levels on the first and fifteenth day, but GSH in IBAT remained higher even after fifteen days.

Work at cold storage

1. 1. Work activities in cold storage rooms were assessed by a mailed questionnaire survey of cold storage facilities in Japan.

2. 2. There are nearly 4000 cold storage facilities and about 80% are being kept at temperatures below −20°C.

3. 3. The chief items of stock in storage were marine products, livestock products, frozen food and agricultural products.

4. 4. Methods used for loading and unloading in cold storage rooms are forklift, manual handling, and automatic machines.

5. 5. Use of forklifts appeared to be widespread.

6. 6. Working time differed according to the ambient temperature of the cold storage rooms.

7. 7. Common ailments of cold storage workers are lumbago, bronchitis, neuralgia etc.

Thermal acclimation and hardening in tadpoles of the bullfrog, Rana catesbeiana

1. 1.|Critical thermal maxima (CTMax) and minima (CTMin) were measured to evalute thermal hardening in Rana catesbeiana.

2. 2.|Tadpoles show heat hardening and CTMax acclimation, and both responses are influenced by developmental stage.

3. 3.|The first evidence of cold hardening in vertebrates is reported here.

4. 4.|Heat hardening significantly reduces cold tolerance, but there is otherwise no evidence of a cross-hardening effect.

Heat death and cellular heat injury

1. 1.|Evidence is presented implicating cellular membranes in cellular heat injury. It is proposed this is the site of the primary lesion.

2. 2.|Secondary and tertiary events, resulting from the primary lesion, cause organism death. Those events may be unique to the life style and grade of organisation of the organism.

3. 3.|Thus hyperthermia may cause “excessive” fluidisation of membranes and so cause impairment of membrane permeability and disrupt the stability of membrane enzymes.

4. 4.|Homeoviscous adaptation of membrane fluidity may well have an important role in resistance acclimation as well as resistance adaptation.

Comparison of thermal responses with and without cold protective clothing in a warm environment after severe cold exposures

1. 1. Ten male students remained in a severely cold room (-25°C) for 20 min. thereafter, they transferred in a warm room (25°C) for 20 min.

2. 2. This pattern was repeated three times, total cold exposure time amounting to 60 min.

3. 3. In the warm room, the subjects removed their cold-protective jackets, or wore them continously.

4. 4. Rectal temperature, skin temperatures, manual performance and thermal comfort were measured during the experiment.

5. 5. Removing cold-protective jackets after severe cold exposure increased peripheral skin temperatures and reduced the discomfort in the warm room.

6. 6. However, these results were accompanied by a greater decrease in rectal temperature and manual performance.

7. 7. It is recommended that workers continue to wear cold-protective clothing in the warm areas outside of the cold storage to prevent decreases in deep body temperature and work efficiency caused by repated cold exposures.

Hatching of freshwater sponge gemmules after low temperature exposure: Ephydatia mülleri (Porifera: Spongillidae)

1. 1.|Gemmules of Ephydatia mülleri can withstand exposure to temperatures down to −80°C for 63 days without loss of hatchability.

2. 2.|Hatching is slowed following exposure to temperatures below −27°C.

3. 3.|There is a slight but significant relationship between gemmule size and the time to hatch.

4. 4.|This species can withstand long-term exposure to winter air temperatures occurring within its known geographic range.

A study on thermal environment for physically handicapped persons. Results from Japanese-Hungarian joint experiment in 1990

1. 1. For the scientific evaluation of thermal environment in relatin to human health and comfort, a number of indices have been proposed in the recent 70 years.

2. 2. However, even the newest indices are still not sufficient to explain the general thermal environment for all people including infants, the aged, the disabled etc., because such indices are based more or less on experiments using college age persons.

3. 3. Series of studies to find required thermal conditions for the disabled and the aged have been carried out from 1976 in Japan and from 1988 in Hungary.

4. 4. In 1990, the Japanese and Hungarian research groups have collaborated in an international joint experiment on the thermal environment for the disabled.

5. 5. This paper reports on the results from the first step examinations of the data from above mentioned joint experiment.

Lactate modeling and its application to endurance training

1. 1. In this short review, previous studies regarding the modeling of lactate (La) response to exercise and its application to endurance training have been summarized.

2. 2. Additionally the result of a recent study by the present authors are shown.

3. 3. Several models for La response to step and ramp exercise are already proposed and deductions derived from them are used for practical purposes such as the prediction of race performance in middle-and long-distance runners as well as for construction of their training regimens.

4. 4. Only a limited number of models however have tried to quantify whole body La kinetics to exercise in humans concomitantly with describing physiological mechanisms underlying the observed phenomenon.

5. 5. In a recent study described further in this paper a 2 compartment model was used for the purpose of clarifying the current “La production vs degradation” controversy during La adaptation to training.

6. 6. It was determined from this investigation that the La metabolic clearance rate during recovery is enhanced by the endurance training.

7. 7. This is in accordance with another recent observation of an increased La metabolic clearance rate at high absolute work rates and all relative work rates during exercise.

Temperature gradients in the nasal cavity of the rabbit

1. 1.|Temperatures at four sites along the ventral nasal concha were recorded in four unrestrained rabbits exposed to ambient temperatures from 0 to 35°C.

2. 2.|The nasal temperatures decreased and temperature gradients from proximal to distal parts of the concha increased in cold-exposed rabbits.

3. 3.|The temperature gradients increased also during panting in heat-stressed rabbits.

4. 4.|The ventral nasal concha is suggested to be an efficacious heat exchanger both in cold and hot ambient, due to its geometry and vascularization.

The hypothalamus neurons response to the signals from surface and deep skin thermoreceptors

1. 1.197 neurons have been studied in the anterior and posterior hypothalamus of 30 rabbits; 28 of them responded to the thermal skin stimulation. The response latencies were different and varied from 2–5 to 50–80 s; the response latencies of the same neuron were constant under repeated stimulation.

2. 2.These differences were concluded to be accounted for by some neurons being connected to the surface skin layers thermoreceptors, and others to the deeper ones. These facts support the hypotheses that the thermoregulatory system measures the intensity of the heat flow through the skin.

Indoor environmental study and post occupancy evaluation in an office environment

1. 1. The objective of this paper is to investigate the indoor environment from the viewpoint of interaction between physical environment and the human responses. The field survey has been conducted over 1 year.

2. 2. A continuous measurement has been carried out for 1 week and distribution of variables have been measured for 1 day.

3. 3. The attitude of workers was investigated by a questionnaire.

4. 4. As the result, average luminance represented more than 1000 lx in the new building, in contrast with less tha 300 lx in the existing building.

5. 5. There was a significant difference of the occupants' response to the light environment between the two buildings.

6. 6. Measured thermal conditions are on the edge of the ASHRAE comfort envelope in summer, and in the neighborhood of the lower dry limit of the envelope in spring.

7. 7. The occupants' evaluations were remarkably changed before and after the moving. The office environment is better than that of the factory.

Biochemical changes in tissue composition of Periplaneta americana (Linn.) acclimated to high and low temperatures

1. 1.|Cold acclimation apparently favours an increase of water content in fat body, but not in coxal muscle, of cockroaches.

2. 2.|A remarkable enhancement in the accumulation of total protein in fat body characterizes the cold acclimation of cockroaches, particularly adult males (175% increase in protein/DNA ratio). The increase in protein content of coxal muscle during acclimination to 15°C, observed in nymphs (16%) and males (16%) but not in females, is less pronounced than that of fat body.

3. 3.|A diminution (28–32%) in the free amino acid/DNA ratio due to cold acclimation has been recorded in both coxal muscle and fat body of nymphs and females, but not in males.

4. 4.|No qualitative change occurs in the free amino acid spectrum of haemolymph and tissues of this insect during acclimation to 15 and 35°C.

5. 5.|An augmentation (15–30%) of the RNA/DNA ratio occurs in fat body and coxal muscle of nymphs and males but in fat body alone of females following cold acclimation.

6. 6.|The glycogen reserve has been shown to increase by up to 30% in fat body and coxal muscle of cold acclimated cockroaches compared to warm acclimated ones.

TLV in cold environments

1. 1. The risks encountered during cold exposure are general body cooling or local cooling of parts of th body.

2. 2. Measures of cold stress must account for the effects of climate, clothing and metabolic heat production on heat balance.

3. 3. The combinaed effect of air temperature, mean radiant temperature, humidity and air velocity determines the cooling power of the environment.

4. 4. The cooling power can be easily converted into a required insulation value (IREQ) for whole body heat balance.

5. 5. Extensive cooling of hands and feet may be a limiting factor, even when sufficient total insulation is provided. In addition the cooling effect of wind on unprotected skin must be considered.

6. 6. Recommendation regarding acceptable exposures can be expressed as lowest ambient temperatures and time limits as function of available protection and activity level, with due attention to both general and local effects.

Numerical analysis of thermal structure in heated room

1. 1. Two-dimensional numerical analysis is carried out on the thermal structure in an empty heated room of actual size under a steady state.

2. 2. Three types of heater, floor heating, side-wall heating and hot-air heating were used.

3. 3. The thermal structure in a room formed by each heating type is investigated in consideration of the energy transfer through the window of the room.

4. 4. The results indicate that floor heating is most suitable in a room without window from a viewpoint of the thermal comfort.

5. 5. In a windowed room, it is desirable that a heater should be located by the side of the window to prevent the cold draft.

Preferred temperature of the elderly after cold and heat exposures determined by individual self-selection of air temperature

1. 1. The purpose of the study was to investigate the preferred temperature of the elderly after cold and heat exposures.

2. 2. Eight elderly and 9 young females wearing the same type of clothing were exposed to cold (10°C), moderate (25°C) or hot (35°C) environments for 30 min in the exposure room.

3. 3. Then they moved to the self-control room in which the temperature was set at 25°C, and the room temperature increased or decreased continuously by 0.4°C every minute.

4. 4. The subjects were instructed to operate the switch when they felt uncomfortably warm or cool during a 90-min period.

5. 5. In operating the switch, the changing in room temperature shifted to the opposite direction.

6. 6. The ambient temperature was recorded continuously and analyzed as the preferred temperature, which was defined as the midpoint temperature of the crest and trough of temperature records.

7. 7. The preferred temperatures after the cold exposure were significantly higher than those of other exposure conditions in the elderly.

8. 8. On the other hand, in the young, there was no significant difference in the preferred temperature among the exposure conditions.

9. 9. Although the effect of exposure to cold or hot environments decreased in the latter parts of self-control, the elderly still preferred the higher temperature after cold exposure.

Characteristics of the temperature regulation system in the human body

1. 1. To study a complex biological system such as human temperature regulation, it is necessary to consider both physiological experiments and theoretical analysis.

2. 2. This paper presents the characteristics of this temperature regulation system obtained from a mathematical model, together with experimental data and the influence of exercise and clothing.

3. 3. The experimental results showed a good agreement with the theoretical results.

Interactions of season and temperature acclimation in the control of metabolism in Amphibia

1. 1.|Studies concerning the seasonal variation and the temperature acclimation of metabolism and their control in Amphibia are reviewed.

2. 2.|Both season and temperature acclimation affect the activities of the central and autonomic nervous systems.

3. 3.|These changes are mediated especially by alterations in the activity of the thyroid and through the autonomic nerves.

4. 4.|The fact that common control mechanisms are involved may explain some of the often observed metabolic interactions of season and temperature acclimation.

Muscle potentials and temperature acclimation and acclimatization in flight muscles of workers and drones of Apis mellifera

1. 1.Muscle potentials in fibrillar flight muscles of worker and drone honeybees were recorded extracellularly at thoracic temperatures from 30 to 10°C.

2. 2.Extinction temperatures for muscle potentials were higher in drones for all treatments.

3. 3.Cold acclimation (15°C) lowered extinction temperatures significantly in workers and drones. Acclimitization changed extinction temperatures significantly only in drones.

4. 4.Cold acclimitization had a bigger effect on the rate of muscle potential amplitude decline with decreasing temperature than acclimation.

5. 5.Acclimation and acclimitization had no effect on the increase of muscle potential duration with falling temperature.

6. 6.Muscle potential frequency during shivering was not much different between cold and warm treated bees.

Acclimatory responses in enzymatic activity and metabolite concentrations in the tropical scorpion Heterometrus fulvipes

1. 1.|Changes in tissue metabolite concentrations and enzyme activities in the pedipalpal (PM) and heart (HM) muscles of the tropical scorpion Heterometrus fulvipes show that the metabolism in PM and HM is fundamentally reorganized following low (18°C) and high (38°C) temperature acclimation.

2. 2.|Changes in metabolite concentrations show that metabolite biosynthesis showed increases after cold acclimation but decreases after warm acclimation.

3. 3.|Similarly, changes in enzyme activities show a preponderance of glycolysis and HMP shunt activity after cold acclimation, while after warm acclimation glycogenolysis, oxidative metabolism and gluconeogenesis predominated.

4. 4.|Higher metabolite concentrations and enzyme activities both before and after thermal acclimation in HM reflect its greater compensatory abilities.

Experimental study on convective heat transfer coefficient of the human body

1. 1. The convective heat transfer coefficient of the human body is essential to predict convective heat loss from the body.

2. 2. The object of this paper is to calculate the convective heat transfer coefficient of the human body using heat flow meters and to estimate the thermally equivalent sphere and cylinder to the human body.

3. 3. The experimental formulae of the convective heat transfer coefficient for the whole body were obtained by regression analysis for natural, forced and mixed convection.

4. 4. Diameters of the thermally equivalent sphere and cylinder of the human body were calculated as 12.9 and 12.2 cm, respectively.