Relationship between acute lethal doses of various matal cations to rabbit, rat or mouse and their physico-cnemical properties was investigated in due consideration of binding strength between metal cations and biological important substances. It was found that logarithm of the acute lethal dosesof metal cations decreased linearly with the increase of the following physico-chemical properties of metal cations; logarithm of stability constant of metal-EDTA chelate, product of electronegativity and ionic charge, and standard electrode potential.
Distribution of benzene in the body with special reference to the bone marrow was measured after theinjection of 14C-labelled benzene into rabbits. By a single dose of benzene, no metabolites of benzene were measured in the bone marrow, but by injecting daily for several days, a large amount of metabolites was accumulated. It was assumed that these metabolites detected in the bone marrow were present in free state or in com-bined state with proteins. They were not detected in the DNA fraction ofthe bone marrow prepared according to the method of Key et al, whilst the basic composition of DNA molecule prepared from poisoned rabbits differed from the normal as reported previ-ously. Therefore, the appearance of this abnormal DNA molecule may be caused by a disturbed synthetic process of DNA in the bone marrow of poisoned rabbits. The physical structure of this abnormal DNA molecule was alsodiscussed.
In order to study the mechanisms of the toxicity of quartz particles on the intraperi-toneal monocyte, the chemical composition of the cells which were treated with two sorts of quartz particles with different surface were determined. That is, the amount of amino acid, total nitrogen, acid-soluble nucleotide, nucleic acid and the number of cells were measured on the monocytes with LI2M (quartz treated with alkaline after 2 minutes grind-ing) or QI-1001I (quartz ground for 100 hours) and withoutquartz particles. The amounts of these substances in monocytes with QI-100H were almost equal to those in monocytes without quartz particles. In the monocytes with LI2M the change of the amounts of amino acid, total nitrogen and nucleic acids corresponded with the change of the number of cells, whereas the amount of acid-soluble nucleotide decreased very rapidly and remarkably. The amount of acid-soluble nucleotide decreased with increasing dust doses and the linear relationship was observed between the amount of LI2M added to monocytes and the amount of acid-soluble nucleotide in these cells.In column chromatographic analysis, the acid-soluble fraction of monocyte showed apparent 11 peaks of nucleotides, that is, CMP, DPN, AMP, GMP, UMP, ADP, GDP, ATP, UTP and GTP. Among acid-soluble nucleotides in monocytes with LI2M, the amount of adenine nucleotide decreased clearly, especially the amount of ADP was about 42% of the control.
In 24 healthy volunteer males, changes of pulmonary airway resistance were measured in the following sequence of inhalation ; 1) after short term inhalation of hydrogen peroxide aerosols in two groups of 4.6μ and 1.8μ of their count median diameter, 2) sulfur dioxide (1-60 ppm), 3) mixture aerosols of hydrogen peroxide and sulfur dioxide, 4) bronchodilator, 5) the mixture aerosols of the same to 3), and their effects were compared with the preexperi-mental control level. A synergistic increase of the response was observed by the mixture aerosols which were recognized as sulfuric acid mist. Difference of the particle size resulted in different response to the respiratory tracts.
Applying the theory and the technique of gas chromatography, adsorption effectiveness of surface was studied on a pulse flow system of active carbon and acetone. The adsorp-tion effectiveness "f" was defined as the ratio of the following two distribution coefficients at the same vapor pressure and temperature; one (μ1) was for the pulse flow adsorption obtained gas chromatographically and the other (μ2) was that for the adsorption equilibrium from the adsorption isotherm measurements. Gas chromatographic observations were carried out on the column packed with active carbon, and under helium carrier gas, liquid acetone of 0.05 ml, 0.10 ml and 0.20 ml was injected respectively. Values of μ1 varied with sample volumes, whereas the μ2 values were remained con-stant in this experimental conditions, in which the vapor pressure was as low as 10-2 to 10-4 mmHg. Consequently the adsorption effectiveness of the surface "f" varied with the change of μ1 values, and the maximum obtained was 53% at the smallest sample volume and the higher temperature. The ratio of "f" to the gas-solid contact time was almost constant in this experimental range. This fact indicates that the "f" increases with increasing contact time. Greater ratio of surface effectiveness to contact time at 72°C may be due to higher adsorption velocity at higher temperature.
The circuit, in which the photoelectric current of photomultiplier was transformed to digital amount, was developed. This A-D transformation circuit is very simple and has a high sensitivity. The photoelectric current of 5 × 10-4 μA is transformed into one pulse per minute by this circuit. Three kinds of apparatus for the determination of aerosol concentration were devised by means of measuring the intensity of scattered light by this circuit. Responses of these devices are linearly proportional to dust concentration in the same aerosol systems. These apparatus can measure the concentration of the order of 10-3mg/m3 of quartz dust. Significance of dust determination by these devices was also disscussed.