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Biomedical subjects

Y X Liang

Publications and source records attributed to Y X Liang.

30 records · Page 2Linked to original sources
PubMed1991

Distribution and excretion of 3H-sterigmatocystin in rats.

In order to investigate the distribution and excretion of sterigmatocystin, a carcinogenic mycotoxin, radioactively labelled compound was studied in rats. The highest concentration of radioactivity in serum appeared 3 h after administration of 0.5 microCi/g bw. The half-lives of distribution and excretion were 0.51 h and 43.9 h, respectively. The radioactivity was concentrated mainly in liver, stomach, kidney, duodenum and lung and to a lesser extent in fat, muscle, testis, rectum and bone. By 48 h, 56.4% had been excreted in faeces and 20.1% in urine. Biliary excretion may be the major route of excretion of sterigmatocystin.

Animals↗
PubMed1985

Effects of occupational lead exposure.

Fifty-three workers in a battery factory, 52 solderers in a television factory, and 50 embroidery workers (a reference group) were studied. The average air lead levels of the three workplaces were 0.578 mg/m3, 0.002 mg/m3, and 0.001 mg/m3, respectively. Adverse effects in terms of clinical manifestations and biochemical criteria were evident among the battery factory workers. A significant dose-response relationship existed between the toxic effects and the air lead levels. The solderers showed no apparent abnormalities in comparison with the embroidery workers. The early clinical manifestations were dysfunction of the central nervous system, indigestion, arthralgia, and myalgia in the extremities. A positive association was observed between the prevalence of fatigue, mild abdominal pain, and arthralgia and the blood lead (PbB), urinary lead (PbU), and zinc protoporphyrin (ZPP) levels. The symptomatic threshold values of PbB, PbU, and ZPP were 30 micrograms/dl (1.5 mumol/l), 0.045 mg/l (0.2 mumol/l), and 40 micrograms/dl (0.7 mumol/l), respectively. The PbB, PbU, free erythrocyte protoporphyrin, and ZPP levels and the blood aminolevulinic dehydratase ratio could be used as indicators of lead exposure, although ZPP is preferred for a preventive monitoring program. The motor and sensory conduction velocities of the median nerve were slower in the exposed groups than in the reference group. No effects on behavioral function were observed among the solderers.

Central Nervous System Diseases↗
PubMed1985

Cost-benefit analysis of the recovery of carbon disulfide in the manufacturing of viscose rayon.

Constraints in the management of occupational hazards include problems with technical feasibility and costs of control measures. A pilot investigation of the effectiveness of a carbon disulfide (CS2) recovery system in the manufacturing of viscose rayon by means of cost-benefit analysis was conducted at a Shanghai viscose rayon factory. The annual amount of carbon disulfide recovered with the new system reached approximately 1 500 t in 1982. It is estimated that the company has made a net profit of 1 million yuan (about USD 500 000 at the time of the study) per year from this system (almost equal to 10% of the production value of the factory). This study documented a control measure that was both effective in reducing a hazard for workers and economically beneficial to the company.

Air Pollutants, Occupational↗
PubMed1984

An epidemiological study on carbon disulfide angiopathy in a Chinese viscose rayon factory.

To assess long-term vascular effects of occupational carbon disulfide (CS2) exposure, we examined 376 exposed and 325 unexposed Chinese workers with a medical and work-history questionnaire, a chest-pain questionnaire, blood pressure and blood cholesterol measurements, routine urinary tests, monochromatic fundus photography and other tests. Data from 354 exposed and 177 age- and sex-matched reference workers were evaluated. Personal exposure monitorings were performed simultaneously with a passive dosimeter using gas chromatography. Monochromatic fundus photography revealed no CS2-retinopathy characterized by microaneurysms and/or small dot hemorrhages, and no effects of CS2 on blood pressure and blood cholesterol were found. These negative results may have been due to the low daily exposure averages, which varied between 0.01 and 12.8, with a mean of 1.5 ppm. The present study suggested that the no-effect level of CS2 exposure on the development of retinopathy was around 2 ppm (8-h time weighted average), and the absence of adverse CS2 effects among the workers studied supported the current standard for occupational CS2 exposure of 10 mg m-3 in China.

Adult↗
PubMedDate not supplied

Lead cytotoxicity in primary cultured rat astrocytes and Schwann cells.

The cytotoxic effects of lead acetate on primary cultured astrocytes and Schwann cells (SCs) were studied for comparing the sensitivity of the two kinds of cells and exploring the possible mechanism of lead cytotoxicity. The results indicated that the number of astrocytes detached from the culture surfaces were dependent on the concentration and time of lead exposure. Under phase contrast microscopy, increases in the number of vacuoles were observed at doses of 50 and 100 micrograms ml-1 lead after 96 h of lead exposure for astrocytes and 1, 5 and 10 micrograms ml-1 lead after 24 h of lead exposure for SCs. By scanning electron microscopy, the surface changes in astrocytes began to appear at the dose of 10 micrograms ml-1 lead, whereas in SCs it began in 1 microgram ml-1 lead. By transmission electron microscopy, astrocytes exposed to 10, 50 and 100 micrograms ml-1 lead had increased lysosomal densities, the presence of nuclear inclusions and enlargement of rough endoplasmic reticulum, whereas SCs exposed to 1 microgram ml-1 lead began to show swelling of mitochondria and endoplasmic reticulum, cytoplasmic vacuolizations and numerous myelinoid bodies. Increases in the content of lactic dehydrogenase (LDH) leakage from the astrocytes exposed to 100 micrograms ml-1 lead and SCs exposed to 1, 5 and 10 micrograms ml-1 lead were observed, respectively. Decreases in sulphydryl group (SH) levels in astrocytes exposed to 50 and 100 micrograms ml-1 lead and SCs exposed to 1, 5 and 10 micrograms ml-1 lead were also observed. A dose of 1.0 mmol l-1 reduced glutathione (GSH) and 2.0 mmol l-1 dithiothreitol (DTT) could protect astrocytes from lead-induced SH decrease and LDH leakage. Doses of 10-100 mumol l-1 cAMP were shown to have a protective effect on lead-induced SH decrease in SCs. No significant changes of GSH or lipid peroxidation (LPO) were observed in astrocytes. The results indicated that SH was involved in lead-induced cytotoxicity of astrocytes and SCs, and SCs were more sensitive to lead-induced cytotoxicity than astrocytes.

Animals↗
PubMedDate not supplied

Study on OELs for enzyme-containing detergent in China.

This study is aimed at setting occupational exposure levels for total detergent dust and enzymes in detergent industries. The study population consisted of 795 workers from four enzyme-containing detergent manufacturing plants (A1, A2, B1 and B2), and 156 control workers from an electronic assembly factory. Work environment monitoring was conducted using high volume of air sampler fro measuring the concentration of total dust (mg/m3), and analyzing the level of enzyme (ng/m3) by ELISA method. A standard questionnaires, pulmonary function test, and skin prick test are used to assess health effects. The levels of detergent total dust varied from 0.2 mg/m3 to 12.54 mg/m3. For enzyme levels, in A1, B1 and B2, the concentration ranged from non-detectable to 9.92 ng/m3 and in A2, the concentration was analyzed by enzyme activity methods and was expressed as Gu/m3 (1 Gu/m3 = 16 ng/m3). The concentration is between 0.16-31.36 ng/m3. Non-specific irritation rates in exposed workers were significantly higher than that in controls. Based on the data collected from A1, B1 and control plants, 95% benchmark dose lower bound were calculated as 1.17 mg/m3. The difference of pulmonary function between exposed workers and controls is not significant. The results of SPT showed that neither Savinase- nor Alcalase-induced sensitization was found in controls. The prevalence rates of sensitization for Savinase and Alcalase were ranged between 3.2% and 31% in all enzyme-containing detergent manufacturers investigated. No case of occupational asthma was observed. For total dust, 1 mg/m3 is suggested as permissible concentration-time weighted average (PC-TWA), and 2 mg/m3 as permissible concentration-short term exposure limit (PC-STEL). For the enzyme Subtilisins, 15 ng/m3 is suggested as PC-TWA, and 30 ng/m3 as PC-STEL.

China↗
PubMedDate not supplied

Posttraumatic stress disorder in co-workers following exposure to a fatal construction accident in China.

To assess the mental disturbances induced by accidents at work, 41 male workers who had witnessed a fatal work accident were evaluated utilizing the criteria for posttraumatic stress disorder (PTSD) from the ICD-10 Classification of Mental and Behavioral Disorders. The Hamilton Depression Rating Scale (HDRS) was also administered to the exposed workers, as well as to 47 non-exposed construction-worker controls. The two groups were well matched with respect to age, years of employment, and years of education. They were all of Han sect; and lifestyles, incomes, and living conditions were similar. The exposed workers had a high rate of PTSD: 11 of 41 (26.8%) at one month and five of 39 (12.9%) four months after the fatal accident. The exposed groups' scores for depressive symptoms were significantly higher than those of the controls, including: 1) depressed mood, 2) guilt, 3) initial insomnia, 4) middle insomnia, 5) delayed insomnia, 6) decreased interest in work and other activities, 7) anxiety, 8) somatization, and 9) gastrointestinal symptoms (p < 0.05, p < 0.01, p < 0.001). Fatal work accidents, a major hazard in the construction industry, affect not only the victims but also the mental health of other workers. PTSD and associated emotional disorders related to exposure to serious work accidents deserve more attention for clinical and research purposes.

Accidental Falls↗
PubMedDate not supplied

A neurophysiological study among Chinese CS2-exposed workers.

A neurophysiological study was carried out to examine peripheral neurotoxicity of extremely low levels of CS2, that is, less than 2 ppm (TWA-8hr) among Chinese viscose rayon workers. From the subjects who participated in a 1981 cross-sectional medical survey, 70 male workers exposed to CS2 and age-matched unexposed workers were randomly selected for the present neurophysiological examination. The conduction velocities of motor, sensory and slower motor fibres of the right ulnar nerve were measured using the same methods as those in the study by Seppäläinen (1974). Skin temperature was measured at the middle of the volar surface of the right forearm with a Thermistor thermometer. According to an earlier occupational hygiene survey in the plant, current personal exposures determined by a passive dosimeter method were very low; the average of daily exposure of 7 jobs studied was 1.45 ppm (range 0.2-5.0). Past and current area sampling data also suggested that occupational hygiene conditions regarding CS2 exposure in the plant had been extremely good for the previous 6 years. The present neurophysiological study clearly showed that significant reduction in the conduction velocities of motor and slower motor fibres of the ulnar nerve was detected as a consequence of chronic exposure to low levels of CS2. In the previous cross-sectional medical survey, no retinopathy was found among Chinese workers exposed to CS2 at this level. These results suggested that an effect of CS2 on the peripheral nerve would appear earlier than that on the retina.

Adult↗