Right palms of 10 healthy subjects were exposed to vibration of 5 minutes' duration and a series of skin temperature changes was measured from both middle fingers and both great toes, with a view to clarifying the remote effect of hand-transmitted vibration on vasoconstrictor tone in exposed and unexposed digits. While the skin temperature changes varied widely from subject to subject, significant skin temperature decreases occurred in the presence of the vibratory load. In addition, a positive correlation of significance was demonstrated in skin temperature decrease between the vibration-exposed fingers and each of the other unexposed three digits. It was hence concluded that local vibratory application yielded vasoconstriction in the remote digits as well as in the neighbouring region, and it was considered that the somatosympathetic reflex mechanism probably contributed to this response.
Lead acetate treatment intraperitoneally at the dosages of 1 mg, 2 mg, 4 mg and 6 mg/kg over a period of 30 days altered spermatogenesis in rats. Inhibition of Δ5-3β-hydroxysteroid dehydrogenase was parallel with the high concentration of testicular cholesterol and low concentration of ascorbic acid, alkaline phosphatase and protein in most of the treated groups. Gradual increase in blood and testis lead alongwith the proportional inhibition of δ-aminolevulinic acid dehydratase levels indicated the intensity of lead toxicity in rats. Data revealed that alteration of spermatogenesis in lead treated rats might be due to the inhibition of steroidogenesis.
The quality of adsorbents used for commercial adsorption samplers or for previous empirical studies of adsorption sampling was surveyed with regard to specific surface area and pore size distribution derived from N adsorption isotherms. Five kinds of grain coconut-shell active carbons, 3 kinds of sheet-type active carbon preparations, 2 kinds of grain silica gels and 3 kinds of porous polymer beads were submitted to N2 adsorption isotherms measurements. The grain active carbons had BET-specific surface areas ranging from 812 to 1309 m2/g, sheet-type active carbons from 348 to 625 m2/g, silica gels from 332 to 637 m2/g and porous polymers from 320 to 491 m2/g. Transformation of the isotherms into V-t plots showed that the surface areas of active carbons were almost entirely borne by micropores with radii less than 3.54Å, but the surface areas of silic agels and porous polymers o were more borne by pores with radii larger than 3.54Å. These surface properties should be referred to in the design and handling of adsorption sampling devices.
The velocity of spontaneous desorption of various solvents from carbon cloth K-filter TF-1500 (CC) housed in a diffusive sampler holder was examined. Among the 16 most popular organic solvents (acetone, benzene, butyl acetate, ethanol, ethyl acetate, n-hexane, isopropyl alcohol, methanol, methyl ethyl ketone, methyl isobutyl ketone, styrene, tetrachloroethylene, toluene, 1, 1, 1-trichloroethane, trichloroethylene and m-xylene), the desorption half-time (T1, 2) was various depend-ing on the solvent and was shortest with methanol (57 min) followed by ethanol (20 h) and acetone (38 h). As T1, 2 values observed were mostly larger than 24 h, it was possible to conclude that diffusive sampling with CC is generally applicable to the exposure monitoring of a wide range of solvents. The application to methanol is, however, practically impossible due to its rapid spontaneous desorp-tion. The solvent with short T1, 2 of spontaneous desorption can be best predicted from log (n-octanol/water partition coefficient) [log (Po/w)] ; a solvent with log (Po/w) of less than zero will have T1, 2 of less than 24 h, and diffusive sampling may not be applicable to monitoring of such solvents. Packing of CC in aluminum foil immediately after the termination of exposure and storage at 4°C jointly im-proved the preservation of the impregnated solvents so that no significant loss was detected for any solvent tested except for methanol in 4 days.