Chuhei Yamauchi

Allergy to laboratory animals: an epidemiological study

A large cross sectional survey was carried out using a self administered questionnaire to examine the prevalence of laboratory animal allergy (LAA) and the factors associated with its development. Out of 5641 workers who were exposed to animals at 137 laboratory animal facilities in Japan, 23.1% had one or more allergic symptoms related to laboratory animals. The commonest symptom as rhinitis. About 70% of LAA subjects developed symptoms during their first three years of exposure. Atopy (past and family history), the number of animal species handled, and the time spent in handling correlated significantly with the development of LAA as did some types of job. A close relation between nasal symptoms and exposure to rabbits and between skin symptoms and exposure to rats were found. LAA subjects developed symptoms most quickly to rabbits.

Evaluation of a one-way airflow system in an animal room based on counts of airborne dust particles and bacteria and measurements of ammonia levels

Air cleanliness in the working area of an animal room equipped with a conventional turbulent flow air distribution systems was compared with that in a similar room fitted with a one-way-flow air distribution system; in this, the supply air flowed from the working area through the racks of cages and was removed from the exhaust side. Before the introduction of animals, the air in the working and exhaust areas of both rooms was ascertained to be Class 100. With animals in situ, however, whereas in the turbulent airflow room both the workspace and exhaust air reached about Class 10 000 (with particle counts, bacterial counts and ammonia levels being almost the same) in the one-way-flow room, the air in the work space only went up to about Class 1000. With the addition of sliding doors or curtains in front of the rack in the one-way-flow room the work space air was maintained at Class 100 with almost no dust particles over 1 μm in size, airborne bacteria or ammonia being detectable. A comparison of all factors measured showed that whereas in the turbulent flow room the contamination of the work space air was 91% of that of the exhaust air, in the one-way-flow room it was only 47%, with curtains added this was reduced to 7% and with sliding doors to only 2%. In the latter case, contamination levels increased markedly on both sides during and immediately after cage changing, but recovered to the pre-cage changing levels within 30 min in the personnel working area and within 60 min on the exhaust side.

Efficiency of Heat Exchanging Equipment in a Laboratory Animal Facility

The efficiency of the so-called econovent heat exchanging equipment located in the Institute of Laboratory Animal Sciences, Faculty of Medicine, Kagoshima University, was measured as follows: The air velocity was decreased to about 64% of that with the fresh air ducts, but a sufficient air volume was supplied maintaining an air change of 12 times per hour or more. The efficiency of the econovent showed a little difference depending upon air conditioning systems. The average efficiencies were 81%, 75% and 76% for temperature, absolute humidity and enthalpy, respectively. The energy required for the air conditioning in this facility in September 1975 and January 1976 estimated by enthalpy hour almost agreed with that estimated using a calorie meter or steam meter. It was assumed that a total of 63% and 60% energy were saved in the cooling and heating seasons, respectively, using the econovent.

Influences of the Complex of Environmental Temperature, Relative Humidity and Air Velocity on the Body Temperature of Restrained Mice

Effects of the complexes of environmental factors, such as ambient-temperature, relative humidity and air velocity, on the body temperature were investigated in restrained mice. Observations were carried out before and after 60 min-exposure to various triple combinations among environmental temperatures of 15, 25 and 35 degreesC, relative humidities of 40, 65 and 90%, and air velocities of 0.2, 1.0 and 2.0 m/sec. The analysis of variance about the differences of body temperature revealed significant effects of the environmental temperature and the air velocity levels, while no significant effects were recognized of the relative humidity. Effects of the double factors, either the environmental temperature plus the relative humidity or the environmental temperature plus the air velocity, were significant at 5 or 1% level respectively. However, effects of the double factors the relative humidity plus the air velosity, as well as the triple factors were not significant. Under the environments consisted of triple factors, the environmental temperature of 20 and 25 degreesC, the relative humidities of 40 and 70% and the air velocities of 0.1 and 0.5 m/sec, significant effects at 1% level were recognized only in the environmental temperature levels. In the relative humidty or the air velocity levels, and the double or triple factor levels, no significant effects were recognized. From the results obtained, the effective temperature (Te) was indicated by the formula, Te=t+100x-v square root 38-t, in which were given the environmental temperature in t degrees C, the absolute humidity in x kg/kg and the air velocity in v m/sec.