Averaged auditory evoked response (AER) from the brain surface in rats injected intraabdominally with three kinds of gasoline: nonleaded white gasoline (WG), tetrae-thyl lead containing gasoline (LG), and gasoline containing tetraethyl lead, benzene, toluene, and xylene (LBTX), was analysed. Aftear the gasoline injection the mean peak latency of each wave in AER was delayed in direct proportion to the degree of poisoning. The amplitude of AER also increased or decreased proportionally to the degree of gasoline intoxication. In the WG group, AER showed little variation in latency and amplitude. However, in the LG group, characteristic delay in latency and decreased amplitude of AER were observed. In the LBTX group, one to three days after injection, AER variation was similar but larger than the VER of the LG group. When the rat was in a moveless lethargic condition the peak latencies of the positive and the negative waves were remarkably delayed and the amplitudes increased. he poisonous and anesthetic effects of gasoline on the synaps and on the nerve cells were very strong in the order of WG<LG<LBTX.
Stress responses induced in healthy young men by three types of task (MT: mental task of addition-subtraction of two figures, ST: static physical task of holding 2 kg load with both hands, DT: dynamic physical task of pedalling at 360 kgm/min) were compared. Pulse rate rose significantly during every task though at the different rates and quickly raturned to control level in the recovery period of 30 min. Systolic pressure rose markedly only during DT, while diastolic pressuae tended to rise during ST and MT. Every task was accompanied by significant increases in specific gravity of plasma and plasma protein concentration, and by a significant decrease in plasma water per cent. This gave an evidence of hemoconcentration. Although these three indices returned wholly to their control levels in the recovery period for DT and ST, none did in the recovery period for MT. From the calculations of the net change in plasma volume, of the ratio of plasma protein concentration to plasma water per cent and of the correlation between them, a suggestion was obtained that the movement of plasma fluid due to the mental task might be different from that due to the physical tasks.
Individual difference in catecholamine excretion was studied. The amine excre-tion, some mental abilities, physique and physical capacities were investigated on 119 senior high school students. By factor analysis, five factors were extracted from these data. The three factors have considerable loadings in catecholamine excretion and mental or physical characteristics, and suggest that catecholamine excretion, especilly adrenaline, has some relation not only to mental abilities but also to physical characteristics.
Blood volume changes were determined using 51Cr tagged red cells during and after the experimental CO exposure. Blood volume reduced by more than 20% of the initial volume during the CO exposure, and it was mainly due to the reduction of plasma volume caused by the increased vascular permeability. This hemocon-centration was reversible by the application of the hyperbaric oxygenation. Our present findings would offer a possible explanation of the hemoconcentration and its recovery by the hyperbaric oxygen therapy observed in the patients with acute CO poisoning.
GOT, GPT, LDH, total Ac-P, prostatic Ac-P, Al-P, cholesterol, free fatty acid, Ca, and P in plasma were measured once a week on rabbits injected subcutaneously with 0.5 and 1.0 mg Cd/kg daily for 11 weeks respectively, and Cd, Cu, Mn, and Zn contents in organs were determined at the termination of the experiment. Prostatic Ac-P activity, cholesterol, and free fatty acid levels in plasma rose in the early stage of administration, and GOT, GPT, LDH, and Al-P activities rose in the latter stage of administration. Ca and P levels in plasma did not change in all periods of the experiment. From these results, it could be concluded that a measurement of prostatic Ac-P, cholesterol, and free fatty acid is available for knowing an excess intake of Cd. Cd contents in heart, lungs, spleen, and testes of rabbits injected with 1.0 mg Cd/kg increased significantly compared with those with 0.5 mg Cd/kg, but a difference between the two groups in Cd contents in liver, kidneys and submandibular glands which contained high concentration of Cd was not recognized. Zn contents in organs of rabbits injected with Cd increased remarkably, while Cu contents decreased generally. This phenomenon was especially remarkable in liver and kidneys.
Effect of pre-synthesized metallothionein in livers of rats on cadmium distri-bution in the soluble fractions was investigated in vitro and in vivo. The liver of a mail rat injected with cadmium (1 mg/kg, intraperitoneally) was removed at 24 hr after the injection and soluble fraction was prepared from the tissue. Cadmium was concentrated in a low molecular weight portion corresponding to metallothionein in the soluble fraction, and zinc was also included in this portion. When this soluble fraction was added with cadmium in vitro, most of cadmium was found in this portion, and zinc was replaced by cadmium. The proportion of these metals was 1 : 1 in molar ratio. Male rats were pretreated with a small amount of cadmium (0.3 mg/kg, intraper-itoneally) at 24 hr before injection with a challenge dose of cadmium (3 mg/kg, in-traperitoneally). Cadmium intake in the livers was significantly promoted, and cadmium concentration in the soluble fraction was higher in comparison with non-pretreated rats. A large amount of cadmium was also found in the low molecular weight portion, whereas zinc in this portion disappeared at 2 hr after the challenge injectien. It was probable that this promotion of cadmium intake was brought predominantly by the replacement of zinc in zinc-thionein by cadmium; the proportion being estimated to be the same as in vitro. Thus, cadmium may be more rapidly immobilized in the livers of cadmium pretreated rats than that of non-pretreated rats. On the basis of these findings, the protective effect of the pretreatment against cadmium toxicity was discussed in relation with metallothionein induced by the pre-treatment.
Rapid separation of dopa, noradrenaline, octopamine, adrenaline and dopamine was accomplished by means of high speed liquid chromatography with gradient elution of SCX column by Na+-containing aqueous solution. After this chromatographic separation, adrenaline and noradrenaline were fluorometrically determined by an automated trihydoxyindole method and dopamine was measured by an automated ethylenediamine method. By the present procedure 1 ng of adrenaline and noradrena-line and 10 ng of dopamine were easily detected. And, the former two amines in urine-alumina extract can be analyzed very rapidly such as 3 samples per hour.