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Biomedical subjects

X R Wang

Publications and source records attributed to X R Wang.

At least 37 records · Page 2Linked to original sources
PubMed2001

Genetic composition and diploid hybrid speciation of a high mountain pine, Pinus densata, native to the Tibetan plateau.

Pinus densata has been suggested to have originated from hybridization events involving P. tabulaeformis and P. yunnanensis. In this study, allozyme differentiation at 12 loci was studied in 14 populations of P. tabulaeformis, P. densata, and P. yunnanensis from China. The observed genetic composition of P. densata supported the hybrid hypothesis and showed varying degrees of contribution from P. yunnanensis and P. tabulaeformis among its populations. These data, together with previous chloroplast DNA results, indicated different evolutionary histories among P. densata populations. To examine the possibility of ongoing hybridization among the three species, we analyzed patterns of linkage disequilibria between allozyme loci in ovule, pollen, and zygote pools. None of these tests suggested that there is significant ongoing gene exchange, implying that populations of P. densata have a stabilized hybrid nature. The normal fertility and high fecundity of P. densata indicate that this hybrid is maintained through sexual reproduction. P. densata represents an example of diploid hybrid speciation in an extreme ecological habitat that is both spatially and ecologically separated from that of its parents.

Alleles↗
PubMed2001

Adverse effects of low-level air pollution on the respiratory health of schoolchildren in Hong Kong.

To evaluate the respiratory effects of long-term exposure to air pollution, schoolchildren (ages 8 to 12 years) from two districts in Hong Kong with contrasting air quality were studied. Parents of 1660 children completed questionnaires on respiratory symptoms, and 1294 children had their ventilatory function tested with a spirometer. After adjustment for relevant covariates, children living in the more polluted district had increased odds ratios for frequent cough (1.74), frequent sputum (1.87), chronic sputum (1.84), and doctor-diagnosed asthma (1.98). Children of both sexes in the more polluted district had significantly poorer lung function, and the differences among girls were more marked. The study provides additional evidence for the adverse effects of long-term exposure to relatively low-level air pollution.

Air Pollutants↗
PubMed2001

Pulmonary function in long-term asbestos workers in China.

The relationship of pulmonary function to exposure to asbestos and radiographic abnormalities has been controversial, especially when smoking is present as a confounder. The aim of the study was to provide further understanding on the radiographic-physiologic associations in nonsmoking and smoking asbestos workers. Radiographic asbestosis, pleural lesion, and pulmonary function were studied in 269 Chinese asbestos workers, with average exposure years of 23 for male workers and 18 for female workers. Their functional data were compared with those of 274 controls without exposure to dust. Although most of the male workers were smokers, none of the female workers smoked. In comparison with controls, asbestos workers had significantly lower lung volume and diffusing capacity, irrespective of gender. Female workers and smoking male workers had lower measurements of forced expiratory volume in 1 second and instantaneous forced expiratory flow at 50% and 25% of forced vital capacity. After adjustment for relevant covariates, asbestos exposure, asbestosis, and pleural abnormalities were associated with decreased parameters of pulmonary function, including lung volume, diffusing capacity, and airway flow. These data indicate that asbestos-related functional defects manifested by lung restriction and mild airway obstruction correlate with exposure to asbestos and with parenchymal and pleural abnormalities, independent of smoking.

Adult↗
PubMed2001

Longitudinal changes in pulmonary function and respiratory symptoms in cotton textile workers. A 15-yr follow-up study.

To evaluate the chronic effects of exposure to cotton dust, a 15-yr follow-up study in cotton textile workers was performed in Shanghai, China from 1981 to 1996. Testing occurred four times during the 15-yr period. The achieved follow-up rates were 76-88% of the original 447 cotton textile workers, and 70-85% of the original 472 silk textile workers (as a control group). Identical questionnaires, equipment, and methods were used throughout the study. The prevalence of byssinosis increased over time in cotton workers, with 15.3% at the last survey versus 7.6% at the baseline, whereas no byssinosis was found in silk workers. More workers in the cotton group consistently reported symptoms than in the silk group, although symptom reporting varied considerably from survey to survey. Cotton workers had small, but significantly greater, adjusted annual declines in FEV(1) and FVC than did the silk workers. Years worked in cotton mills, high level of exposure to endotoxin, and across-shift drops in FEV(1) were found to be significant determinants for longitudinal change in FEV(1), after controlling for appropriate confounders. Furthermore, there were statistically significant associations between excessive loss of FEV(1) and byssinosis, chest tightness at work, and chronic bronchitis in cotton workers. Workers who consistently (three or four of the surveys) reported byssinosis or chest tightness at work had a significantly greater 15-yr loss of FEV(1). We conclude that long-term exposure to cotton dust is associated with chronic or permanent obstructive impairments. Consistent reporting of respiratory symptoms, including byssinosis and chest tightness at work, is of value to predict the magnitude and severity of chronic impairments in textile workers.

Adult↗
PubMed2001

Effect of long-term fertilization on soil nitrate distribution.

A thirteen years long-term field fertilizer experiment was conducted to monitor the effect of different fertilization on soil nitrate distribution. The results showed: (1) Applying relative excessive N fertilizer could result large quantities of NO3- residue and NO3- movement downward in soil profiles; amending phosphate fertilizer or organic manure with nitrogen fertilizer together could significantly improve the status of NO3- leaching downward due to the balanced uptake of nutrients by crops. (2) Appropriate amounts of nitrogen fertilizer which was equal or smaller than the optimal fertilization rate could not result in more NO3- leaching in Northern China. (3) Precipitation influenced the amounts and depth of soil NO3- leaching: NO3- could move to 80 cm depth or below at autumn or at the next spring when rainfall was higher during the rainy season through July to September in North China.

Agriculture↗
PubMed2001

Effects of cadmium on rat sperm motility evaluated with computer assisted sperm analysis.

OBJECTIVE: To study effects of cadmium on rat sperm motility evaluated with computer assisted sperm analysis. METHODS: Different doses of cadmium chloride (0.2, 0.4, 0.8 mg Cd/kg BW) were administrated i.p. to adult male Sprague-Dawley rats. Control animals received the same volume of 0.9% NaCl solution. After 7 days, the rats were sacrificed with their testes removed. A part of one testis was used for testicular sperm head counts and daily sperm production observation. The motility of spermatozoa obtained from cauda epididymides using the "diffusion" method was measured by computer assisted sperm analysis (CASA). RESULTS: The sperm head counts and daily sperm production decreased significantly in the high dose group. The motility of spermatozoa in the middle dose group was reduced significantly. No motile sperm was found in the high dose group. The results suggest that germinal epithelium was impaired irreversibly in a short time to produce toxic effects on spermatogenesis at high cadmium doses. CONCLUSION: Cadmium may reduce sperm motility at a dose far below the dose affecting sperm production at this time point. The motility of sperm is an early and sensitive endpoint for the assessment of cadmium toxicity on male reproduction.

Animals↗
PubMed2001

[Preliminary separation and identification of the neurotrophic substances from dorsal spinal cord of chicken embryos].

Extracts of spinal dorsal horn and ventral horn of chicken embryos hatched for 9 days were separated by Sephadex G-75 gel filtration, and different chromatographic fractions of DI and DII, VI and VII were obtained. The neurite-outgrowth promoting effects of the various fractions were assayed by the dorsal root ganglion (DRG) culture in vitro. It was shown that DII, but not DI, fraction of the dorsal horn extract exhibited a significant neurite-outgrowth promoting effect on DRG. By means of SDS-PAGE, the molecular weight of DII fraction ranged from 61 to 15 kD. VI and VII fraction of ventral horn showed no obvious effect on neurit-outgrowth of DRG in vitro.

Animals↗
PubMed2001

[Protective mechanism of tianmacuzhi granules in brain].

OBJECTIVE: To provide pharmacological evidence for the protective effects of Tianmacuzhi Granules (TMC) in mouse brain in a ischemia--reperfusion model. METHOD: Receptor binding test of NMDA receptor and M receptor in brain, GPx activity determination in brain and liver effected by different dose of TMC were performed. RESULT: TMC could reduce the NMDA receptor activity, increase the M receptor activity and GPx activity of cerebral cortex and hippocampus tissues significantly. CONCLUSION: TMC might antagonize ischemia-reperfusion injury of brain by reducing the glutamate neurotoxicity and increasing the function of cholinergic nerve and effects of anti-peroxidization in brain.

Animals↗
PubMed2001

[The role of immune enhanced enteral nutrition on plasma amino acid, gut permeability and clinical outcome (a randomized, double blind, controlled, multi-center clinical trail with 120 cases)].

OBJECTIVE: To evaluate the role of arginine, RNA and omega 3 fatty acid enriched enteral nutrition. METHODS: The study was designed as a prospective, randomized, double blind, multi-central trial. It was an isocaloric and isonitrogenous intake in both groups. The protocol was approved by the Ethic Committee and, written informed consents were obtained. RESULTS: There were 120 patients enrolled in this protocol. After data were input to computer, open the code. 118 out of 120 patients completed the study and, 2 of them were dropped out. One is because the nasal jejunum tubes dropped and not willing to be replaced. Second patient had fistula of anastomosis on 4th days after operation. There were finally 60 patients in the study group and 58 in the control group. There were no liver or renal functions damage and, obvious adverse in both groups. Plasma amino acid profile: There was significant difference (delta) of plasma arginine levels pre- and after study [(33.7 +/- 58.5) mumol/L vs (-2.4 +/- 30.7) mumol/L] (P = 0.004). Intestinal Permeability (lactulose/mannitol ratio): The differences (delta) of lactulose/mannitol ratio pre- and after the study were 0.017 +/- 0.012 in study group and, 0.027 +/- 0.016 in control group. (P = 0.047). Immunological markers: Humoral immunity: The differences of IgM levels pre- and after the study were (0.6 +/- 0.4) g/L in study group and, (0.2 +/- 0.4) g/L in control group(P = 0.006). Cellular immunity: The differences (delta) of CD3 levels pre- and after the study were (3.8 +/- 5.2)% in study group and (0.3 +/- 6.5)% in control group (P = 0.01). In CD4, (3.4 +/- 5.3)% in study group and, (-0.3 +/- 5.7)% in control group (P = 0.032). Clinical Outcomes: There was no infection-related in study group and, 2 abdominal infection patients in control group. No significant difference was found between groups (P = 0.46). The hospital stays were (13 +/- 2.5) days in study group and, (14.5 +/- 3.0) days in control group (P = 0.004). The cost for full hospitalization was (15,122 +/- 6,279) Yuan in study group and, (17,403 +/- 7,091) Yuan in control group. There was 2,281 Yuan lower in study group (P = 0.07). The costs for nutritional drugs were (1,383 +/- 242) Yuan in study group and, (707 +/- 111) Yuan in control group. The difference was 676 Yuan higher in study (P = 0.001). CONCLUSION: Immune enhanced enteral nutrition had better plasma arginine level, intestinal permeability marker, IgM, CD3 and CD4. Also had less hospital stay and, less totaled hospital cost in study group.

Adult↗
PubMed2000

Respiratory symptoms and functional status in workers exposed to silica, asbestos, and coal mine dusts.

This study aims to provide further understanding of physiologic and symptomatic changes and radiographic abnormalities due to exposure to silica, asbestos, and coal dusts. Questionnaires and pulmonary function tests were given to 220 silica, 277 asbestos, and 511 coal workers from three different industries in China. Posteroanterior chest radiographs were classified as stages 0, I, II, and III according to degree of parenchymal fibrosis. Significantly poorer pulmonary function and a higher prevalence of dyspnea and chronic cough were observed in workers with pneumoconiosis than those without, irrespective of dust type. Workers with stages II and III silicosis had worse pulmonary function and more common symptoms relative to workers with equivalent coal workers' pneumoconiosis or asbestosis. After adjusting for relevant confounders, reductions in the spirometric parameters and single breath diffusing capacity for carbon monoxide (DLCO) and the occurrence of respiratory symptoms were associated with increasing stage of silicosis, whereas lower DLCO and the occurrence of symptoms were associated with increasing stage of asbestosis and coal workers' pneumoconiosis. The study suggests that despite the differences in degree and pattern due to exposure to different fibrogenic dusts, respiratory impairments of all of the workers are associated with the presence and progression of parenchymal fibrosis and smoking.

Adult↗
PubMed2000

Changes in tissue metals after cadmium intoxication and intervention with chlorpromazine in male rats.

Cadmium (Cd), one of the most dangerous heavy metals, has a very similar ionic radius to calcium (Ca). The interference of cadmium in calcium homeostasis may play an important role in cadmium toxicity. Recent reports indicate that calmodulin (CaM) inhibitors such as trifluoperazine and chlorpromazine (CPZ) could protect rodents against cadmium toxicity. It was also reported that pretreatment of mice with zinc (Zn) could reduce the adverse effects induced by cadmium. The aim of this study is to determine whether Cd changes the balance of other essential metals such as Zn and copper (Cu) in rat tissues, and whether CPZ can reverse these changes which are induced by cadmium intoxication. Adult male Sprague-Dawley (SD) rats were injected intraperitoneally (i.p.) with cadmium chloride (CdCl2) (0.2, 0.4, 0.8 mg Cd/kg body weight) alone and 0.4 mg Cd/kg in association with CPZ (5 mg/kg) daily for a week. The control animals were injected with normal saline only. The results showed that the cadmium content in the liver, kidney and testis increased significantly with a dose-response relationship. Cadmium treatment markedly increased the Zn and Ca content in some of the tissues. Hepatic and renal metallothionein (MT) increased significantly after cadmium intoxication. CPZ treatment, however, reduced cadmium content in liver, but not blood and kidney. CPZ seemed to decrease the content of MT in liver and significantly increase the amounts of MT in kidney. These data suggest that the intervention of cadmium with tissue essential metals may play a role in cadmium toxicity in rats, and calmodulin inhibitors to some extent can reduce the adverse effect of cadmium by decreasing the cadmium load in tissues and reversing the unbalance of essential metals.

Animals↗
PubMed2000

Effect of TCDD on maternal toxicity and chorionic gonadotropin--bioactivity in the immediate post-implantation period of macaque.

The purpose of this experiment was to observe the alterations in bioactivity of chorionic gonadotropin (CG) associated with early fetal loss (EFL), induced by the environmental toxin TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) in the cynomolgus macaque. Ten of twelve females administered single doses of 1, 2 or 4 microg/kg TCDD on gestational day (GD) 12 had EFL from ten to twenty days later. Seven control animals treated only with the vehicle had normal pregnancies. Blood samples were repeatedly collected for hormone evaluation, from two days before treatment to thirty-one days following treatment. Immunoreactive monkey chorionic gonadotropin (mCG) was measured in serum using ELISA, and bioactive mCG was measured using a luminescence LH/CG bioassay. No change in immunoreactive mCG levels was detected as a result of TCDD, treatment, but bioactive mCG levels were significantly lower in TCDD-treated animals compared to controls. This change in bioactivity of mCG was also reflected in the ratio of mCG bioactivity to mCG immunoreactivity (B/I ratio) which began to rise in normal pregnancies by GD 20, but did not rise in TCDD treated animals. These results demonstrate that normal pregnancy in the monkey, as in humans, is characterized by a post-implantation change in the B/I ratio of CG. These findings therefore suggest that changes in the production of bioactive CG may be used as a biomarker of environmental toxicant exposures which lead to EFL.

Animals↗
PubMed2000

Overview of occupational health research in Hong Kong.

A review was undertaken to collect and collate information on studies that have been done in Hong Kong in the field of occupational health. Both published and unpublished reports related to occupational health research in Hong Kong during the period 1966-1997 were sought. The data collection was performed through various means, including electronic Medline searches and manual searches of local academic and professional journals. Relevant information for each report was abstracted and collated. A total of 357 studies/reports related to occupational health in Hong Kong were identified during the period 1964 to 1997. Few reports were available before 1980. Roughly similar numbers of reports were found for chemical hazards, dust and ergonomics (including psychosocial factors). In addition, there were substantial numbers of reports on physical hazards. Organic solvents, silica dust, compressed air and noise were the specific hazards more frequently reported. The manufacturing and construction industries were the more frequently studied groups. Recent studies have focused more attention on the non-industrial sectors, including the service sector, offices, schools, hospitals and transport. The vast majority of the reports were based on cross-sectional surveys. A significant number of published reports were discussion or review papers. Most studies were less than adequate in terms of documenting causal relationships. Despite the limited resources, occupational health researchers in Hong Kong have made great achievements in the past decades. The study subjects and the numbers of studies reflected major health problems accompanying the development and changes of local industries and trades from time to time.

Bibliometrics↗
PubMed2000

[Comparison of several rib rings with intercostal muscles for tracheal replacement in dogs].

OBJECTIVE: To compare the effect of several types of rib rings with intercostal muscles for the replacement of trachea in thorax. METHODS: The surface layer of the third rib of dogs were ripped off and curved into triangular, quadrilateral and polygonal form. These three types of rib rings with intercostal muscles were used to replace a segment of trachea in thorax. RESULTS: The stability of triangular rib ring was very well, but stricture of ring were often happened because of its smaller internal diameter. These stability of quadrilateral rib ring was the worst. The polygonal rib ring presented the biggest diameter and good stability compared to the other two kinds of rings. If silicone tube was supplemented in the polygonal rib ring, the quality of artificial trachea was excellent. CONCLUSION: The rib rings with intercostal muscles are successfully used for replacing the defect of trachea in canine thorax. The polygonal rib rings have the best quality in the three types of rib ring for tracheal replacement.

Animals↗
PubMed2000

[Protective effect of xinxin capsule on learning and memory impairment in mice].

OBJECTIVE: To investigate the effect of Xinxin Capsule on the scopolamine or ethanol induced impairment of learning and memory retention in mice. METHOD: Step-through and Morris Water-maze methods, wer used to the protective effect of Xinxin Capsule(0.4, 0.8, 1.6 g.kg-1, ig, 16 d) on the scopolamine or ethanol induced impairment of learning and memory retention in mice. RESULT: The Capsule(0.8, 1.6 g.kg-1, ig,) can turn over the Scope so as to induce the impairment of learning, and the Capsule((0.4, 0.8, 1.6 g.kg-1, ig) can improve the ethanol induced impairment of memory retention in mice. CONCLUSION: Xinxin Capsule helps regain as well as impair the learning and memory retention in mice.

Animals↗
PubMed2000

[Determination of six ginsenosides in Panax species by high performance liquid chromatography].

A method for the determination of six major ginsenosides in panax species by high performance liquid chromatography (HPLC) with UV detection at 203 nm is described. The six major ginsenosides, which were reported to account for more than 90% of the total ginsenosides content of the panax species' root, were successfully separated using gradient HPLC. The column to be used was a Cosmosil-C18 reversed-phase, 4.6 mm i.d. x 250 mm, 5 microns (Japan), connected with a C18 guard column and the mobile phase was acetonitrile and water. The calibration curves of the six ginsenosides were all linear over the range of 25 mg/L-300 mg/L with good correlation coefficients (> 0.99). The recoveries for the ginsenosides were all above 80%. For real samples and recovery study, the major ginsenosides were ultrasonically extracted by methanol. The extracts were evaporated to 1 mL, under vacuum, at about 50 degrees C and then diluted by methanol. Just prior to HPLC analysis, the sample solutions were filtered using a C18 cartridge. This method has been successfully applied to the analysis of four commercial panax samples.

Chromatography, High Pressure Liquid↗