Tuberculin hypersensitivity was significantly reduced in BCG sensi-tized guinea pigs preinjected with sensitizing quantities of beryllium sulfate, but the same reduction was not observed in animals preinjected with beryllium citrate. These results support the view that the suppressed tuberculin responses in beryl-lium factory workers may result from beryllium sensitization rather than from the toxicity of beryllium salts. Studies on chronic beryllium patients and factory workers exposed to beryllium have indicated that their Mantoux responses may be reduced compared to the non-exposed population1-3). However, Hardy4) found no difference between the two populatons. Recently, Nishikawa et al5) reported that the percentage of Mantoux negative workers, previously exposed to beryllium oxide, declined from a high to normal level over a period of three years. Reduced Mantoux reactivity in patients with chronic beryllium diseases, is probably a result of debility. However, in beryllium factory workers it may be due to toxicity or to sensitization to beryllium salts. We have carried out a study using BCG sensitized guinea pigs, to determine the effects of beryllium exposure on the skin and " in vitro " tuberculin hyper-sensitivity. Sensitizing (beryllium sulfate) and nonsensitizing (beryllium citrate) injections of beryllium were givens6).
From observations on load carriage on subjects engaged solely for the manual carriage of compact loads of a given range of weights, over a range of self selected speeds, Gross Load (Body weight plus weight of external load) and the speed of carriage were found to be the principal influences in determining the energy expenditures of the tasks and the cardiorespiratory changes during their performance. Based on the data collected a chart has been developed which allows the strenuousness of load carriage tasks to be suitably altered by adjustments of Gross loads and speeds of carriage so that they may not become unduly fatiguing for those employed in them.
A simple and specific method for the quantitative determination of hippuric acid and methylhippuric acids is described. Urine samples were applied to a silica gel plate (silicagel, 60 F254), and developed with chloroform-acetone-acetic acid. The spots of hippuric acid and methylhippuric acids were identified by illuminating the silica gel plate with an ultraviolet lamp, scratched out and ex-tracted with pyridine. The color was then developed with acetic anhydride and p-dimethylaminobenzaldehyde (DAB) in pyridine at 40°C for 60 min. The absor-bance at 458 nm was determined against a blank containing pyridine, acetic anydride and DAB.
A 19-year-old man who had sniffed lacquer thinner for 8 months was found to suffer from cerebellar dysfunction and visual disorders. He had blurred vision, dysarthria, nystagmus, slight intention tremor, staggering gait and an abnormal EEG. The thinner contained 68% toluene, 18% ethyl acetate, 9% methyl isobutyl ketone (MIBK), 3% isopropyl alcohol (IPA) and 3% butyl acetate. The concentration of each solvent in the plastic bag used for sniffing was 12, 000 ppm toluene, 11, 500 ppm ethyl acetate, 6, 000 ppm IPA and 2, 000 ppm MIBK. Previ-ously reported cerebellar dysfunctions due to toluene or toluene-containing solvents are summarized and discussed. Based on these reports and the present case, toluene is presumed to impair function in the order of the vermis, cerebellar hemispheres, and cerebrum, when a relatively high concentration of toluene is inhaled. The effects of organic solvents, especially toluene, on the cerebellum are considered to be very important from the viewpoint of occupational health, since toluene is widely used in industry and many workers are exposed to it.
It it well known that itai-itai disease with the osteopathy is broken out among multiparas, 40 years of age and up Japanese residents. In this paper we described an experimental study of effect of pregnancy on cadmium treated rats. Female mature rats were administered drinking water containing 50 and 200 ppm cadmium as CdCl2. During 180 days of the experiment, three times of pregnancy were succesful, though slight depression of body weight gain was noticed in the 200 ppm group. The cadmium was accumulated in the kidneys, liver and bone proportionally to the amount of cadmium administered. No significant change was recognized in serum calcium, phosphorus and alkaline phosphatase levels after 180 days. Though cadmium 200 ppm treated rats showed slight histological lesions in the proximal convoluted tubles of the kidney, there appeared to be no osteo-malacia including excess formation of osteoid tissue.
Using male mice of ICR strain, the effect of cycloheximide on metal-lothionein production and the acute toxicity of Cd were studied. Followiug ad-ministration of Cd alone (2.5 mg/kg body weight), most of the Cd accumulated in the lives and kidney was found in the metallothionein (MT) region. Zn was also detected in this region, being enhanced with increasing time after Cd injection. Following combined treatment with Cd and cycloheximide (total dose 2.0 mg), the proportions of Cd and Zn in the cell sap were slightly decreased. In the MT region, the proportion of Cd was markedly decreased by cycloheximide. In par-ticular, in the Cd + Cy-10 hr group, this proportion in the liver and kidney was half of that in the Cd-10 hr group treated with Cd only. The proportion of Cd increased at 24 hr after Cd injection, even though the mice were treated with cycloheximide. Simultaneously, the proportion of Zn in the MT region also in-creased. Mice injected with 2.5 mg Cd/kg body weight did not die up to 24 hr after this metal injection. Following the combined treatment with Cd and cycloheximide, however, 6 out of 10 mice died within 24 hr after Cd injection. These results suggest that the toxicity of Cd is modified by cycloheximide, and MT synthesis contributes to the appearance of this toxicity.
Copper sulfate was given to male rabbits intraperitoneally and the copper concentrations in the plasma, red cells and EtOH-CHCl3 treated fraction of the cells were determined. The concentration of copper in the plasma increased markedly and in the red cells increased slightly after administration of 1 mg copper/kg of body weight, while the copper level in the EtOH-CHCl3 treated fraction remained constant. In this experiment, the ceruloplasmin activity in the plasma increased, while the superoxide dismutase activity in the red cells remained unchanged. The form of the copper present in the plasma was also examined by gel filtra-tion on a Sephadex G-150 column. Most of the copper absorbed in the plasma appeared at first in the albumin fractions and was then incorporated into cerulo-plasmin fractions.
In order to measure human head vibration, rigid tooth impressions which were closely fitting to the upper central incisors of the subjects were made from acrylic resin. The head vibration was measured with small vibration pickups which had been attached to the tooth impressions. In PART I, three subjects' heads were exposed to a sinusoidal vertical vibra-tion at 15 frequencies in the range of 5 to 125 Hz with a constant acceleration amplitude of 0.08 G (RMS). The head vibration was measured on the tooth im-pressions and the results were compared with those on the forehead. The measuring method with the tooth impression was found to be highly reproducible. Based on the results, the head was estimated to hava a resonance of between 50 and 80 Hz. In PART II, the transmissibility of three subjects to sinusoidal vertical vi-bration was assessed on the tooth impressions at 16 frequencies in the range of 3.15 to 100 Hz with a constant acceleration amplitude of 0.1 G (RMS). Measure-ments of the fore-and-aft (X) and vertical (Z) vibration were made in the sitting and standing postures. The mean transmissibility of the subjects was estimated. In both postures, the mean transmissibility of the subjects showed a peak at 5 Hz, and decreased as the frequency increased from 6.3 Hz. The utility of tooth impressions for the measurement of head vibration is discussed.
Occupational lung diseases are caused by fibrogenic dust, numerous allergenic materials, irritant gases and chemical vapours. Beside the improvement of working conditions an effective prevention depends on safe diagnostic methods. During the last decade the forced oscillation technique has become a practicable method to diagnose an airway obstruction. The oscillatory resistance is a parameter which is to obtain during normal ventilation of the patient. In order to get a resistance versus volume curve the oscillatory resistance can be plotted in the course of a complete exspiration. For standardized evalution of the resistance versus volume curve we propose a gradient angle a between the abscissa and a tangent between the neutral point of the system of coordinates and the point of curve, where its sharp rise due to narrowing of small airways begins. In 180 healthy persons we found a mean angle α of 27± 7° for men and 39± 8° for women. Between men and women the difference of the angle a was statisti-cally significant on the 1% level. For smoking and nonsmoking men we found a significant difference on the 1% level. The practical applicability of oscillatory measurement of airway resistance in occupational medicine is demonstrated by examples.