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Biomedical subjects

T Yasugi

Publications and source records attributed to T Yasugi.

At least 91 records · Page 5Linked to original sources
PubMed1991

A personal diffusive sampler for occupational acetone vapor exposure monitoring.

A commercially produced badge-type personal sampler, with water as absorbent and originally designed for monitoring of formaldehyde, was investigated for possible application to monitoring of occupational exposure to acetone, one of the hydrophilic solvents which cannot be monitored so far with activated carbon cloth-equipped diffusive samplers. Under the experimental condition of exposure at constant acetone concentration, the amount of acetone absorbed was proportional to the acetone exposure concentration up to 1500 ppm and duration of exposure for up to 8 h. Inter-sampler variation became wider, however, at 8 h of exposure to 1500 ppm acetone. Loss of acetone in the absorbent water due to spontaneous desorption became significant at 6 h after acetone impregnation of absorbent water. In practice, therefore, limitation of the duration of exposure up to 4 h is recommended.

Absorption↗
PubMed1991

Polymorphisms of serum proteins in Japanese patients with vascular diseases. I. Factor XIIIB, plasminogen and complement types in primary varicose veins.

The polymorphisms of the B subunit of coagulation factor XIII (F13B), plasminogen (PLG), complement C6, C7, factor B (BF) and factor I (IF) were studied among 21 unrelated Japanese patients with primary varicose veins (PVV) by isoelectric focusing followed by immunoblotting. The allele frequencies for F13B*2 and IF*A in PVV patients were significantly higher (F13B*2, p = 0.0047; IF*A, p = 0.0006) than those in healthy controls (n = 60). Significant associations of F13B 2 allotype [p = 0.0220, relative risk (RR) = 13.9] and IF A allotype (p = 0.0006, RR = 10.0) with PVV were observed; however, no significant association of PLG, C6, C7 or BF allotype with the disease was found.

Adult↗
PubMed1990

The method of choice for the determination of 2,5-hexanedione as an indicator of occupational exposure to n-hexane.

To identify the method of choice for analysis of urine for 2,5-hexanedione (2,5-HD) as an indicator of occupational exposure to n-hexane, the end-of-shift urine samples of 36 n-hexane exposed male workers and 30 non-exposed male workers were analyzed for 2,5-HD under three conditions of hydrolysis, i.e. enzymic hydrolysis at pH 4.8, acid hydrolysis at pH 0.5, and without hydrolysis. The 2,5-HD concentrations thus determined were examined for correlation with 8-h, time-weighted average exposure concentrations of n-hexane measured by diffusive sampling. The regression analysis showed that the 2,5-HD concentrations without any hydrolysis correlated best with the intensity of exposure to n-hexane. No 2,5-HD was detected in the urine of the non-exposed subjects under the analytical conditions with no hydrolysis. Thus, the analysis without hydrolysis was considered to be the method of choice from the viewpoint of simplicity in analytical procedures, sensitive separation of the exposed from the non-exposed, and quantitative increase in the amount of 2,5-HD after n-hexane exposure.

Environmental Monitoring↗
PubMed1990

Biological monitoring of occupational exposure to isopropyl alcohol vapor by urinalysis for acetone.

The relationship of the intensity of occupational vapor exposure to isopropyl alcohol (IPA) with urinary excretion of acetone and unmetabolized IPA was studied in 99 printers of both sexes, who were exposed to up to 66 ppm IPA (as time-weighted average), together with toluene, xylenes, methyl ethyl ketone and/or ethyl acetate. Acetone and IPA concentrations in urine were studied also in 34 non-exposed subjects. Acetone was detectable in the urine of most of the non-exposed, and the urinary acetone concentration increased in proportion to the IPA exposure intensity (r = 0.84 for observed, non-corrected values), whereas the correction for creatinine concentration or specific gravity of urine did not give a larger correlation coefficient. IPA itself was not found in the urine of the non-exposed, and was detectable in urine of only those who were exposed to IPA above a certain level, e.g. 5 ppm. The present study results suggest that urinary acetone is a valuable index for biological monitoring of occupational exposure to IPA as low as 70 ppm.

1-Propanol↗
PubMed1990

Urinary excretion of unmetabolized acetone as an indicator of occupational exposure to acetone.

Acetone concentrations in urine samples from 28 workers exposed to acetone in a fiber-reinforced plastics factory were determined by directly injecting urine supernate into a gaschromatograph with FID detectors. Acetone concentrations in the urine from ten nonexposed subjects were also determined. The 8-h time-weighted exposure intensity of individual workers was monitored by means of diffusive sampling. Acetone concentration in urine and acetone concentration in the breathing zone showed a linear correlation to each other. The study results indicate that the correlation coefficient is high enough to enable use of the urinary level of acetone as an indicator of occupational exposure to acetone.

Acetone↗
PubMed1989

Changes in density and architecture of microvessels of the rat mammary gland during pregnancy and lactation.

This paper deals with changes in intralobular microvascular density and architecture of the rat mammary gland during the reproductive cycle. Morphometrical analysis of india ink-perfused histological sections showed that the vascular density (the percentage of the total area of the vascular lumen to the whole lobular area), was consistently low before pregnancy and slightly increased by the 5th day of gestation. The vascular density increased twofold from the 5th to 10th days and decreased gradually thereafter. This substantial increase may presumably be associated with rapid glandular development, and the subsequent decrease may reflect the hypertrophy of individual acini. Scanning electron microscopy of corrosion casts showed that blood vessels were sparse before the 5th day of gestation and proliferated by capillary sprouts and globular outgrowths of venules by the 18th day. After the 12th day, the blood vessels were organized into round lumps which appeared to correspond in size to individual lobules. By the 18th day, the vessels were remodeled into highly ordered basket like units which disintegrated by the 20th day. The findings suggest that homogenious acini, formed temporally, eventually undergo uneven growth.

Animals↗
PubMed1988

Small polydisperse low density lipoproteins in familial hyperalphalipoproteinemia with complete deficiency of cholesteryl ester transfer activity.

Lipoprotein abnormalities were analyzed in 3 cases of marked hyperalphalipoproteinemia caused by complete deficiency of cholesteryl ester transfer activity. The probands were all men, aged 34, 43 and 48 years, respectively. The serum high density lipoprotein (HDL)-cholesterol levels of these patients were higher than 150 mg/dl (157-254 mg/dl), while serum total cholesterol levels ranged from 227 to 360 mg/dl. Sequential flotation-ultracentrifugation analysis disclosed that low density lipoprotein (LDL)-cholesterol was slightly decreased and that cholesteryl ester accumulated solely in the HDL2 fraction, which was also enriched with apolipoprotein E. Cholesteryl ester transfer activity was completely absent in all of these cases. High-performance liquid chromatography showed a decrease of LDL particle size in combination with a marked enlargement of HDL particle size. Analytical ultracentrifugation disclosed heterogeneity of LDL with the presence of small LDL subpopulations. We conclude that hyperalphalipoproteinemia due to complete deficiency of cholesteryl ester transfer activity is characterized by the presence of both small polydisperse LDL and markedly large HDL enriched with cholesteryl ester and apolipoprotein E.

Adult↗
PubMed1988

Effects of ketanserin tartrate on serum lipids in patients with essential hypertension.

Several antihypertensive agents such as thiazide diuretics and some beta-blockers have recently been shown to adversely affect lipid metabolism. Moreover, there is a growing suspicion that the adverse effect on plasma lipids might outweigh the favourable effect of lowering blood pressure. The effect of ketanserin tartrate (20 to 60 mg daily), a new antihypertensive drug, on blood lipids was evaluated in a 12-week non-comparative clinical trial in 34 patients with mild or moderate hypertension. Ketanserin reduced systolic and diastolic blood pressure by 12.2 and 9.8%, respectively, without altering heart rates. Total cholesterol and low density lipoprotein (LDL)-cholesterol levels in the fasting plasma were observed to decrease significantly by 6.3 and 8.8% respectively, whereas mean triglyceride and high density lipoprotein (HDL)-cholesterol remained almost unchanged. These changes were consistent irrespective of their initial values. Significant decrease in apolipoprotein B and E was also observed. Apolipoprotein A-I, A-II, C-II and C-III were not altered significantly. It is speculated that ketanserin affects mainly LDL-cholesterol. Based on these findings, ketanserin is considered to have a potentially beneficial effect on coronary risk profile and should be given full consideration when drug therapy is selected for patients with mild to moderate hypertension.

Adult↗
PubMed1983

Changes of serum total cholesterol and triglyceride levels in normal subjects in Japan in the past twenty years. Research committee on familial hyperlipidemia in Japan.

Serum lipid levels of 10,977 normal Japanese subjects in 1980 were determined by a joint study of 14 institutions, specializing in lipid research, located in 9 districts of Japan. The data obtained were compared with those in 1960 and 1970. Total cholesterol (TC) levels in 1980 increased with age except for the 1st decade and reached maximum (205 mg/dl) at the 7th decade. The mean value in any age was higher than that of 20 years ago by 10-15 mg/dl. Triglyceride (TG) levels also increased with age and reached maximum (130 mg/dl) at the 7th decade. The mean values of subjects over the 5th decade were higher than those of 10 years ago by 10-20 mg/dl. In contrast with TC and TG, HDL-cholesterol levels were highest at the 1st decade and declined gradually with age. TC and TG levels of younger age (1st to 3rd decade) were equal to or even higher than those of Americans in 1972-76. It was concluded that serum lipid levels of Japanese have increased in the past 20 years and approached to the levels of Europeans and Americans.

Adolescent↗