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Biomedical subjects

S Kira

Publications and source records attributed to S Kira.

At least 181 records · Page 10Linked to original sources
PubMed1980

Comparison of several methods for the measurement of urinary hippuric acid as an index of toluene exposure.

The levels of hippuric acid in the urine of people exposed to toluene vapour were measured by paper chromatography, direct colorimetry, high performance liquid chromatography and gas chromatography. The control was a similar group not exposed to toluene vapour. The values were analyzed statistically, conversion equations calculated, and the propriety of these equation discussed. Since the three chromatographic methods gave similar values, the measurement of urinary hippuric acid by these methods can be used as an index of toluene exposure. The colorimetric method gave higher levels the chromatographic methods, especially for the urine of people not exposed to toluene. This may have been due to glycine conjugates (other than hippuric acid) developing a similar color, resulting in elevated values for hippuric acid. This colorimetric method should be used with caution for biological evaluation of workers with low toluene exposure.

Air Pollutants, Occupational↗
PubMed1979

Ultrasonographic evaluation of ventilatory effect on inferior vena caval configuration.

Ventilatory effect on inferior vena caval configuration was studied by ultrasonography in 14 subjects, including 5 with chronic obstructive pulmonary disease, 3 with cardiac tamponade due to carcinomatous pericardial effusion, one with tuberculous constrictive pericarditis, and 5 normal subjects. The inferior vena caval lumen decreased in the early inspiratory phase, reached a minimum at the end of inspiration, distended again during expiration, and closed transiently 2 to 3 cm below the diaphragm during maximal inspiration. These ventilatory changes of the inferior vena cava reversed with increase in intrathoracic pressure during the Valsalva maneuver and positive-pressure ventilation. When the central venous pressure was increased, as in cardiac tamponade, the inferior vena cava was fully distended through the entire phase of inspiration and expiration. Collapsibility of the inferior vena cava was inversely proportional to central venous pressure when the pressure was less than 10 cm H2O, but not when the pressure was greater than approximately 10 cm H2O. Our results suggest that the study of inferior vena caval configuration with ultrasonogrphy is a valuable noninvasive clinical aid for estimating central venous pressure and for analyzing inferior vena caval hemodynamics in various clinical conditions.

Central Venous Pressure↗
PubMed1979

Sampling and analysis of organic solvent vapours--with special reference to sampling tubes for a short time and for the working period.

The present paper concerns the sampling and analysis of organic solvent vapours for a short period of time and for the working period. Porous polymer beads, Porapak Q, was applied to the adsorbent of the sampling tube for mixed vapours of aromatic compounds (benzene, toluene and xylenes). The adsorbent was packed in stainless steel column of a suitable size, and the adsorbed vapours were released by heating in the flasher then analysed by gas chromatography. The concentrations of the mixed vapours could be measured simultaneously with sufficient recoveries at the ordinary concentrations in the working yeard. The sampling conditions by pumps and the practical recoveries were tested. Being sucked with the vacuum pump using a Gastek detection tube (100 ml), the recoveries proved to be almost 100%. Being sucked with portable diaphragmatic pumps at a slow flow rate (22 ml/min), the recoveries were constant with only small variations. At a relatively fast flow rate (220-230 ml/min), the recoveries were not so high as those at the slow flow rate. These findings indicate that the sampling tube with Porapak Q is useful for aromatic compounds not only as a room air sampler for a short period of time but also as a personal air sampler.

Air Pollutants↗
PubMed1977

Measurement by gas chromatography of urinary hippuric acid and methylhippuric acid as indices of toluene and xylene exposure.

A gas chromatographic method was applied to the determination of the urinary glycine conjugates, hippuric, o-, m- and p-methylhippuric acids. These were extracted with ethyl acetate from urine after acidification with hydrochloric acid. The internal standard solution (heptadecanoic acid methanol solution) was added before extraction and a diazomethane-ether-ethanol solution was subsequently added to the dried extracts. The methylated residues were dissolved in methanol and injected into a gas chromatograph as described by Buchet and Lauwerys (1973). By the combined use of gas chromatography and mass spectrometry the methyl esters of hippuric acid and m-methylhippuric acid were identified in the urine of a volunteer who had been exposed to toluene and m-xylene vapours. When the urine specimen contained salicyluric acid (a urinary metabolite of salicylic acid) two sharp peaks were observed. The faster peak coincided with m- or p-methylhippuric acid. The upper limit of urinary hippuric acid concentration in healthy subjects with no occupational exposure was calculated by this method to be 1.026 microgram/ml (fiducial limit 5%) after correction to 1.024 for variation in urinary density.

Adult↗