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Biomedical subjects

S J Liu

Publications and source records attributed to S J Liu.

At least 73 records · Page 4Linked to original sources
PubMed1993

Dose-dependent increase in subjective symptoms among toluene-exposed workers.

A factory survey on dose-response relationship in toluene toxicity was conducted in 1985-1989 in four cities in China. The examination items consisted of personal diffusive sampling for TWA exposure measurement, questionnaires on subjective symptoms, hematology and serum biochemistry, and clinical examination including simple neurology tests. Hippuric acid was also determined in urine samples collected at the end of the shift. With selection criteria that (1) complete results were available on all study items and (2) valid toluene exposure data (i.e., toluene shared 90% or more of the exposure) were obtained for the exposed, 452 toluene-exposed workers (206 men and 246 women; toluene exposure at 24.7 ppm as GM) and 517 nonexposed controls (246 men and 271 women) were selected. The subjective symptoms increased in close association with the intensity of exposure to toluene; the threshold concentration appeared to exist at 100 ppm in the case of symptoms during work, and it might be at 50-100 ppm when symptoms off work were evaluated. During the work with exposure at higher concentrations, various symptoms possibly related to CNS or local effects (e.g., eyes, nose, and throat) were complained, and dizziness and floating sensations were identified as typical symptoms with significant dose-response relationship. Several symptoms persisted off work, most of which were apparently related but not necessarily limited to CNS effects. Hematology and serum biochemistry were essentially negative.

Adolescent↗
PubMed1993

Effects of smoking and drinking on excretion of hippuric acid among toluene-exposed workers.

In order to investigate possible effects of smoking and drinking on the metabolism of toluene in occupational settings, 206 toluene-exposed men (mean age: 31.4 years) in shoemaking, painting, or surface-coating workshops together with 246 nonexposed control men (36.8 years) were studied for the time-weighted average intensities of exposure to toluene, hippuric acid concentration in shift-end urine samples, and the two social habits of smoking and drinking. The mean daily consumptions of cigarettes and ethanol were about 20 pieces and 10 g among smokers and drinkers, respectively. The geometric mean toluene concentration among the exposed subjects was about 20 ppm, with a maximum of 521 ppm. Regression analysis after classification of the subjects by smoking and drinking clearly demonstrated that the two social habits, when combined, markedly reduce the hippuric acid level in the urine of workers exposed to toluene. There was a significant association between smoking and drinking habits, which hindered separate evaluation of the effects of the two habits on toluene metabolism. Comparison of the present results with the findings reported in the literature, however, suggested that the observed effects may be attributable to smoking rather than to drinking habits.

Adult↗
PubMed1993

Calcitonin gene-related peptide- and substance P-like-immunoreactive innervation of the anterior pituitary in the rat.

In our previous studies substantial amounts of substance P- and calcitonin gene-related peptide-like-immunoreactive nerve fibers have been identified in the anterior pituitary of the monkey and the dog. They were found to be in close proximity to the gland cells, even making synaptic contacts with some types of the gland cells. The present study investigated in detail the calcitonin gene-related peptide- and substance P-like immunoreactivities of the anterior pituitary in the rat. Though the immunoreactive fibers were not as abundant as in the anterior pituitary of the monkey and the dog, they still appeared in notable amounts. The calcitonin gene-related peptide- and substance P-like-immunoreactive nerve fibers occurred mostly as thin, tortuous, and densely varicose fibers, weaving among the gland cells. They are widely distributed, more in the central part of the gland. Double-immunostaining proved nearly complete co-localization of these two peptides in the nerve fibers. It is hypothesized that the anterior pituitary can be regulated by direct neural factors as well as humoral factors.

Animals↗
PubMed1993

Chronic mastoiditis mimicking recurrence of nasopharyngeal carcinoma: report of a case.

A nasopharyngeal mass with cranial neuropathies usually indicates an advanced neoplastic process. We present a case of nasopharyngeal carcinoma diagnosed and treated 38 years ago. A nasopharyngeal mass recurred with cranial neuropathies and concurrent otologic infection in June, 1990. Repeated nasopharyngeal biopsies were negative with respect to tumors. Suspecting direct extension of the otologic infection, modified radical mastoidectomy was performed. The nasopharyngeal mass resolved after the surgical intervention. Spread of otologic infection from the temporal bone to the nasopharynx may be more common than was previously thought. Clinicians should modify diagnostic approaches in patients with a nasopharyngeal mass and concurrent otologic disease.

Chronic Disease↗
PubMed1992

Toluene vapor exposure and urinary excretion of hippuric acid among workers in China.

A factory survey was conducted in three provinces in China from 1985 to 1989. The time-weighted average toluene concentrations in breathing zone air were monitored by diffusive sampling, whereas hippuric acid (HA) concentrations in shift-end urine samples were measured by high performance liquid chromatography (HPLC). Exposed workers (456 men and women) were those for whom toluene (up to 548 ppm toluene) accounted for greater than or equal to 90% of total exposure (by vapor concentration in ppm), whereas 517 nonexposed controls were recruited from the same factories or from factories of the same region. There was a linear correlation between the intensity of toluene exposure and HA concentration in the shift-end urine. Comparison of the results with findings in the literature shows that the toluene-induced increase in urinary HA concentration among workers in China is significantly smaller than the published values, whereas HA concentrations in urine samples from nonexposed controls are comparable to the levels previously reported.

Air Pollutants, Occupational↗
PubMed1992

Critical levels of blood and urinary cadmium, urinary beta 2-microglobulin and retinol-binding protein for monitoring cadmium health effects.

The critical levels for monitoring cadmium health effects in 358 workers engaged in ore crushing/roasting (cadmium concentration in the workplace air 2.5-6.5 mg/m3), dry smelting (10.8-23.3 mg/m3), cadmium melting (0.01-0.16 mg/m3), and ingot making (2.8-4.7 mg/m3), were investigated. Exposure parameters such as blood and urinary cadmium were determined, together with biological parameters such as proteinuria, amino acids, glucose, beta 2-microglobulin, retinol-binding protein, albumin, plasma beta 2-microglobulin, creatinine clearance, tubular reabsorption of beta 2-microglobulin and phosphate, and blood and urinary levels of zinc, copper and lead. Factor analysis and stepwise regression analysis were then applied to the data to classify parameters and to find the main contributing parameter. Blood and urinary cadmium, urinary beta 2-microglobulin, retinol-binding protein and the ratio of urinary beta 2-microglobulin to albumin were also subjected to multiple correlation analysis, multiple regression analysis and the Chi-square test was applied to contingency tables. It is concluded, based on the data, that cadmium health effects may be assessed by using the following critical levels: blood cadmium: 10 micrograms/l, urinary cadmium: 10 micrograms/g creatinine; urinary beta 2-microglobulin: 2000 micrograms/g creatinine, urinary retinol-binding protein: 200 micrograms/g creatinine and a ratio of urinary beta 2-microglobulin to albumin of 0.001.

Adult↗
PubMed1991

Silica increases cytosolic free calcium ion concentration of alveolar macrophages in vitro.

Rat alveolar macrophages were exposed to silica dust (quartz) suspended in culture medium (SiO2, dry particle size less than 5 microns in diameter) and fluctuation in their cytosolic free calcium content ([Ca2+]i) was detected in cell monolayers with a fluorescent calcium probe (Indo-1AM). Cytosolic free calcium content was correlated with lactate dehydrogenase (LDH) release, an index of cell damage. SiO2 induced a concentration- and time-dependent increase of cytosolic free Ca2+ ion concentration and LDH release. [Ca2+]i was increased about fivefold when cells were exposed to 200 micrograms of SiO2 per milliliter (3 ml per dish) for 2 hr. [Ca2+]i changed within 15 min of SiO2 treatment, whereas LDH release was measurably increased only after 30 min. Chelation of extracellular Ca2+ by 2 mM ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetate did not prevent SiO2-induced fluctuation of macrophage [Ca2+]i, but did partially prevent the SiO2-induced increase in LDH release (p less than 0.01). We conclude that a very early event in SiO2-induced damage of alveolar macrophages involves mobilization of intracellular calcium pools to increase [Ca2+]i. These results suggest that SiO2-induced macrophage damage, a key event in the development of silicosis, may involve perturbation of intracellular calcium homeostasis.

Animals↗
PubMed1991

Magnetic resonance imaging of hyperbaric oxygen treated rats with spinal cord injury: preliminary studies.

Magnetic resonance imaging (MRI) has been performed to assess the efficacy of hyperbaric oxygen (HBO) treatment on experimental spinal cord injury in a rat animal model. A moderately severe injury, similar to Type III injury seen in humans (Kulkarni et al. Radiology 164:837;1987) has been chosen for these studies. An improvement in the neurologic recovery (based on Tarlov scale) has been observed following HBO treatment over a period of 72 hr. Based on MRI, HBO treatment appears to arrest the spread of hemorrhage and resolve edema.

Animals↗
PubMed1991

Peptidergic innervation of the pars distalis of the adenohypophysis.

Substance P-like immunoreactive nerve fibers have been found in the pars distalis of the adenohypophysis in the monkey, dog, and rat. Calcitonin gene-related peptide-like immunoreactive nerve fibers have also been identified in the dog and rat. The peptidergic fibers are closely related to the glandular cells with synaptic contacts demonstrated between them. It is suggested that neural factors may be directly involved in the regulation of the activities of the anterior pituitary.

Animals↗
PubMed1991

Prevalence of hepatitis B virus infection markers among factory workers in Beijing, China.

Nearly 1,000 serum samples were obtained from apparently healthy workers of both sexes in various factories in Beijing during 1988-1989 and were examined for hepatitis B virus infection markers by radioimmunoassay. The overall prevalence (all ages and both sexes combined) of cases positive for HBsAg, anti-HBs and anti-HBc were 3.7%, 36.6% and 37.7%, respectively and the rate of those negative to any of the three markers studied was 56.1%. The infection rate was lower than the values reported early in the 1980s for Beijing populations or the values for populations in other parts of China.

Adolescent↗
PubMed1990

Substance P-like immunoreactive nerve fibers in the pars distalis of the anterior pituitary in the dog.

The pars distalis of the anterior pituitary is known to be regulated by hypothalamic hormones. Recently, we have discovered the presence of substance P-like immunoreactive nerve fibers in the pars distalis of the monkeys. Substance P-like immunoreactivity in the pars distalis of the dog was investigated in this study. A substantial amount of substance P-like immunoreactive nerve fibers with a large amount of varicosities were found. They were widely distributed in the gland, more abundant along its periphery. Most of them were closely related to the glandular tissue, some were located on vascular walls. Substance P-like immunoreactive nerve fibers were also found in the meningeal sheath of the anterior pituitary. They could be followed into the parenchyma of the gland.

Animals↗
PubMed1990

Blood lead levels of Beijing (China) citizens.

Lead levels were determined in 856 blood samples obtained from Beijing citizens who were either factory workers or clerks with no known occupational exposure to heavy metals including lead. Additional analyses were conducted on 74 samples from factory workers in the small city of Jinxi, China. The geometric mean blood lead level (Pb-B) among the general Beijing population 99.2 and 76.1 micrograms 1-1 for non-drinking and non-smoking men and women, respectively, with a statistically significant difference between the two sexes. The effect of drinking was not detectable, whereas that of smoking was suggested, but not conclusive. The Pb-B levels among Jinxi workers did not differ from the levels among Beijing citizens. The Pb-B for inhabitants of Beijing was similar to the levels of inhabitants of a medium-sized city, Hefei, and lower than the values for residents of two heavily industrialized large cities, Shanghai and Shenyang. The values for Chinese citizens appear to be higher than those for Japanese and Korean farmers, but the possibility of urban-rural differences remains to be examined.

Adolescent↗
PubMed1990

Preventive effect of aluminium citrate on silicosis.

Aluminium citrate (Al-cit) was shown to be biologically effective in preventing silicosis. A total of 917 cases selected from both engineering corps of railway and coalmines with stage 0 or 0+ by radiographs were studied. Cases were randomly divided into Al-cit treatment group and control group with continuing dust exposures. Workers in the treatment group were injected with Al-cit at a dose of 120 mg Al/year and these in the control group received a consolatant or nothing during the period of five years. The radiographic changes demonstrated that Al-cit showed clear-cut effects in both retardation of the dust-induced fibrosis and decrease of the morbidity of silicosis.

Adult↗
PubMed1989

Erythropoiesis in cancer patients undergoing immunotherapy.

We studied ten patients with various types of cancer who were being treated with Interleukin-2 (IL-2) and lymphokine activated killer cells (LAK). All patients developed a reticulocytopenic, normochromic, normocytic anemia. We noted some variability but no significant suppression of circulating erythroid progenitors. The levels of erythropoietin were lower than expected for the hemoglobin/hematocrit values. We could not detect Interferon or Tumor Necrosis Factor (TNF) in the serum of these patients; however, the supernatant of LAK cells did contain Interferon and TNF which could be neutralized with appropriate antibodies. These results suggest that the etiology of this anemia is multi-factorial. Administration of recombinant erythropoietin (Ep) may be of benefit in some of these patients.

Anemia↗
PubMed1989

Risk factors in chronic obstructive pulmonary malfunction and "chronic bronchitis" symptoms in Beijing district: a joint study between Japan and China.

A cross sectional study of risk factors in respiratory diseases was carried out in August 1986, in Beijing, China. Inhabitants greater than or equal to 40 years old were selected at random from a rural area, a residential area and an industrial area, using a two stage sampling method. The analysis presented here is based on the sample population of adults who (1) were prepared to be interviewed, using the British Medical Research Council's questionnaire translated into Chinese (n = 3423) and (2) had lung function measurements at the same time (n = 3373). Obstructive lung disease was defined as forced expiratory volume in 1s (FEV1) less than 68% of forced vital capacity (FVC). Seven variables were considered as potential risk factors or confounding factors: area of residence, sex, age, cigarette smoking, history of respiratory disease, socio-economic status and familial component. A modified binary variable regression method developed by Feldstein was used for the adjustment of rate ratios. The adjusted prevalence of obstructive lung disease was highest in the rural area and lowest in the residential area(s). An increase in age, cigarette smoking, low socio-economic status and positive history of respiratory diseases were associated with significantly higher rates of impaired pulmonary function. The other measured factors did not appear to be related to impaired pulmonary function.

Adult↗