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Biomedical subjects

X Wang

Publications and source records attributed to X Wang.

At least 577 records · Page 32Linked to original sources
PubMed2001

[Measurement of formaldehyde in disinfectant with spectrophotometry].

Formaldehyde in disinfectant was measured by acetylacetone spectrophotometry. The regression equation was linear when the formaldehyde concentration was smaller than 10 micrograms/ml. The detection limit was 0.08 microgram/ml. The accuracy was less than 3.9% and the recovery varied between 100.2%-108.2% for formaldehyde disinfectant with different concentration, which was similar to titrimetry. It was demonstrated that the method was simple, reproducible, sensitive, precise and accurate, making it important for assay of formaldehyde in disinfectant when disturbance caused titrimetry unavailable.

Disinfectants↗
PubMed2001

[Collecting of trichloroaniline in the air by micropore filter membrane and determination by gas chromatography].

Trichloroaniline in the air was collected with micropore filter membrane and desorbed with cyclohexane, separated with a column OV-17, OV-210 and determined by GC-ECD. The materals for the filter of collection, solution of desorping and flow-rate of sampling were selected. The detectable limit is 0.01 mg/L. When the concentration of standard solutions is 1-10 mg/L, the relative standard deviation (RSD) is 4.5%-2.3%. There is a linear relation within the range of 0.005-30 mg/L. The sampling efficiency is 98.7%-100%. The samplers were stable for at least 15 days. This method is proved to be accurate, sensitive, fast and simple for sampling and carrying, and it is method is suitable for the determination of trichloroaniline in air, for personal detection and detection in the fields.

Air Pollutants↗
PubMed2001

[Toxicokinetics of terephthalic acid].

In order to study the toxicokinetics of terephthalic acid(TPA) in rats, and provide scientific basis for its biological exposed index (BEI), the concentrations of urine TPA in rats after single oral administration in dose of 100 mg/kg BW were determined by high pressure liquid chromatography. The toxicokinetic parameters were computed by using 3P97 program. The results showed that the first-order kinetics and two-compartment model were noted on the elimination of TPA. The main toxicokinetic parameters were as follows: Ka = 0.51/h, T1/2ka = 0.488 h, T1/2 alpha = 2.446 h, Tpeak = 2.160 h, Ku = 0.143/h, T1/2 beta = 31.551 h, Xu(max) = 10.00 mg. The excretion rates of TPA in urine were about 50%, 52% and 53% in 0-24 h, 0-48 h and 0-72 h respectively after administration. TPA is well absorbed when given orally and rapidly eliminated via urine. Urine TPA at the end of work shift should be considered as a biomarker of exposure for the occupational workers.

Animals↗
PubMed2001

Prostaglandin A(1) protects striatal neurons against excitotoxic injury in rat striatum.

Prostaglandin A(1) (PGA1) reportedly inhibits NF-kappaB activation and induces expression of heat shock proteins. Since both these effects could be neuroprotective, the therapeutic potential of PGA1 in neurodegenerative disorders, where excitotoxicity may contribute to pathogenesis, was evaluated in rat striatal neurons exposed to the N-methyl-D-aspartate (NMDA) receptor agonist quinolinic acid (QA). Intrastriatal administration of PGA1 (5-80 nmol) attenuated QA (60 nmol)-induced internucleosomal DNA fragmentation. The inhibitory effects of a single dose of PGA1 (80 nmol) on QA (60 nmol)-induced DNA fragmentation were observed 12 to 48 h after treatment. PGA1 (80 nmol) also attenuated QA-induced DNA fragmentation when administered up to 4 h after QA exposure. PGA1 significantly decreased the loss of D1 dopamine receptors and GAD(67) mRNA in QA-injected striatum as measured by quantitative receptor autoradiography and in situ hybridization histochemistry, suggesting that it reduced the neuronal loss induced by QA. Protection of striatal neurons against QA-induced death by PGA1 was further indicated by Nissl staining 10 days after QA administration. PGA1 (5-80 nmol) significantly inhibited QA-induced NF-kappaB activation by blocking inhibitory kappaB-alpha degradation but had no effect on activator protein-1 binding activity. PGA1 (80 nmol) treatment substantially increased 70- and 72-kDa heat shock protein levels in striatum. These results indicate that PGA1 blunts NMDA receptor-mediated neuronal apoptosis by a mechanism possibly involving the up-regulation of neuroprotective heat shock proteins and inhibition of NF-kappaB activation. In view of its potent neuroprotective activity, PGA1 could prove useful in the treatment of certain neurodegenerative disorders related to excitotoxicity.

Animals↗
PubMed2001

CD86 expression correlates with amounts of HIV produced by macrophages in vitro.

Primary macrophages from different donors produce variable levels of HIV; however, the mechanisms are unclear. We tested whether variations in cell-surface or cell-cycle characteristics influenced HIV production. We found that greater basal proliferation of the macrophages prior to infection resulted in more arrested in G2M 3 days post-infection (r2=0.7, P<0.04). Likewise, the number of G2M-arrested macrophages correlated with p24 production (r2=0.78, P<0.02) and apoptosis (r2=0.67, P<0.05) later in the infection. Serum-starvation or reduction, which limit HIV spread, reduced G2M arrest and HIV amounts. Surprisingly, the amount of HIV produced correlated with expression levels of the costimulating ligand, CD86, but not with other important molecules, including class II, CD40, or CD54 (r2=0.96, P<0.0005). These data establish donor characteristics related to variable HIV production in vitro and suggest that altered expression of costimulatory ligands may influence HIV production in vivo.

Antigens, CD↗
PubMed2001

Interaction between nitric oxide and renal myogenic autoregulation in normotensive and hypertensive rats.

Blood pressure fluctuates continuously throughout life and autoregulation is the primary mechanism that isolates the kidney from this fluctuation. Compared with Wistar rats, Brown Norway (B-N) rats display impaired renal myogenic autoregulation when blood pressure fluctuation is increased. They also are very susceptible to hypertension-induced renal injury. Because blockade of nitric oxide augments myogenic autoregulation in Wistar rats, we compared the response of the myogenic system in B-N rats to nitric oxide blockade with that of other strains [Wistar, Sprague-Dawley, Long-Evans, spontaneously hypertensive (SHR)]. Renal blood flow dynamics were assessed in isoflurane anesthetized rats before and after inhibition of nitric oxide synthase by Lomega-nitro-arginine methyl-ester (L-NAME, 10 mg/kg, iv). Under control conditions, myogenic autoregulation in the B-N rats was weaker than in the other strains. Myogenic autoregulation was not augmented after L-NAME administration in the SHR, but was augmented in all the normotensive rats. The enhancement was significantly greater in B-N rats so that after L-NAME the efficiency of autoregulation did not differ among the strains. The data suggest that nitric oxide is involved in the impaired myogenic autoregulation seen in B-N rats. Furthermore, the similarity of response in Wistar, Long-Evans, and Sprague-Dawley rats suggests that modulation by nitric oxide is a fundamental property of renal myogenic autoregulation.

Animals↗
PubMed2001

[Fasting insulin level and hypertensive family history in overweighted children].

In order to analyze the relationship between fasting insulin level and body mess index (BMI), blood pressure and lipids, and to discuss the effect of hypertensive family history, 317 healthy children aged 8-11 years including 74 overweighted and 243 non-overweighted were selected randomly from 4 primary schools in Beijing. Anthropometry, fasting insulin and lipids were measured, and the family history of hypertension (FHH) was recorded. After adjusting of age and sex, the levels of blood fasting insulin, cholesterol and triglyceride were significantly higher (P < 0.01) and the ratio of HDL/LDL and apoA/apoB were significantly lower (P < 0.01) in the overweighted than that in non-overweighted children. After controlling BMI, the partial correlation coefficients between fasting insulin and TG, systolic pressure was 0.20 (P < 0.01) and 0.12 (P < 0.01) respectively. Moreover, among the overweighted children, but not among non-overweighted children, those with FHH had a significantly higher fasting insulin than those without FHH (P < 0.01). It is concluded that hypertensive family history may play an important role in contributing to the higher level of serum insulin of overweighted children, and higher serum insulin may concerted with some metabolic disorders in overweighted children.

Body Mass Index↗
PubMed2001

[Analysis on effect of inspection and maintenance (I/M) program for vehicle emission reduction].

An Inspection and maintenance(I/M) programme aims to ensure that motor vehicle emission control systems are functioning properly throughout the two stage idle test. Based on three factors including data from inspection, standard for inspection and failure rate, the effectiveness of the current I/M program was studied through the cumulative distributions. The disadvantages of the cutpoints, institution settings, management, and supervision was also analyzed. The fundamental law of emission limits was proposed.

Carbon Monoxide↗
PubMed2001

[Toxic effects of Cu, Zn and Mn on the inhibition of Chlorella pyrenoidosa's growth].

A standard method of algal bioassay for evaluating the toxicity of toxic chemicals was applied in the study. It was found that safety concentrations of Cu, Zn and Mn for Chlorella pyrenoidosa's growth were 31.8 micrograms/L, 65.0 micrograms/L and 5.5 mg/L, and 96 h-EC50 were 67.3 micrograms/L, 473.0 micrograms/L and 17.0 mg/L, respectively. According to both safety concentration and 96 h-EC50, the toxic sequences of these metals from high to low on the inhibition of C. pyrenoidosa's growth were Cu, Zn and Mn. The different affinities between different metal ions and algal cells are mainly responsible for the different inhibitions of C. pyrenoidosa's growth.

Chlorella↗
PubMed2001

[Study on the relationship between methylenetetrahydrofolate reductase gene C677T mutation and coronary heart disease].

OBJECTIVE: To investigate whether methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism is linked with coronary heart disease (CHD). METHODS: Transmission/disequilibrium test(TDT), sib transmission/disequilibrium test(STDT), and sibship disequilibrium test(SDT) were used. Forty-five CHD pedigrees with at least one CHD patient in the first degree relatives of probands were recruited from Oct. 1998 to Feb. 1999. Among those recruited were 21, 2 and 22 pedigrees with the genotypes of both parents known, one parental genotype unknown and both unknown, respectively. MTHFR genotype was measured by PCR-RFLP technique. RESULTS: Neither the TDT for 23 nuclear families with at least one parental genotype known or the STDT and SDT for 40 sibships found significant difference between the transmitted and untransmitted MTHFR gene 677T allele distributions. CONCLUSION: The above results suggest that MTHFR gene 677T allele is probably not linked with CHD in Chinese population.

Coronary Disease↗
PubMed2001

Effects of ethanol and naltrexone in a model of traumatic brain injury with hemorrhagic shock.

BACKGROUND: Ethanol predisposes to traumatic injury and causes respiratory depression and cardiovascular compromise in models of traumatic brain injury (TBI) and hemorrhagic shock (HS). Endogenous opioids may play a role in ethanol intoxication and TBI. We studied the effects of ethanol and the opiate antagonist agent naltrexone (NTX) in a TBI/HS model. METHODS: Fifty-six pigs (20 kg) were anesthetized with isoflurane, intubated, instrumented, and subjected to fluid percussion TBI with concurrent 30 ml/kg hemorrhage over 30 min. Seven groups were studied: Control, EtOH, NTX, INJ, INJ/EtOH, INJ/NTX, and INJ/EtOH/NTX. Ethanol (2 g/kg IV) was given preinjury, followed by infusion of 0.4 g/kg/hr. NTX 0.3 mg/kg intravenous was given 5 min postinjury. Parameters monitored for 120 min postinjury included minute ventilation (VE), blood pressure (MAP), cerebral perfusion pressure (CPP), cerebral venous lactate (Lac), arterial and cerebral venous blood gases, and brain tissue PtiO2. RESULTS: Ethanol levels at injury were 220 mg/dL. Ethanol-treated animals had depression of hypercapnic ventilatory response, which was reversed by administration of naltrexone. MAP and CPP were significantly lower in injured animals, but were not significantly improved by NTX. Cerebral venous pH was lower and lactate was higher in ethanol-treated animals. CONCLUSION: In this TBI/HS model, NTX reverses ethanol-induced depression of hypercapnic ventilatory response but does not improve MAP, CPP, or metabolic acidosis. This suggests that the respiratory effects of ethanol in TBI, but not the hemodynamic effects, may be mediated by opiate receptor activation.

Animals↗
PubMed2001

[Effects of comprehensive intervention on prognosis of isolated systolic hypertension in the elderly].

OBJECTIVE: To study the effects of comprehensive intervention on prognosis of isolated systolic hypertension in the elderly. METHODS: A 12-years prospective and controlled study was conducted with 207 elderly patients of isolated systolic hypertension enrolled. According to the study project and procedure, 99 patients were allocated to the intervention group and 108 patients in the control group. All the events of cardiovascular diseases, cerebrovascular disorders, nephrovascular diseases and death were recorded and analyzed. RESULTS: A 12-year consecutive follow-up showed that the incidence and mortality of cardiovascular diseases, cerebrovascular disorders, nephrovascular diseases and their ages at death were 41.49%, 26.60% and 75.6 years, respectively, in the intervention group, and 77.45%, 53.92% and 70.2 years, respectively, in the control group, with statistically significant difference. Survival rate in the intervention group was higher than that in the control group. CONCLUSION: Comprehensive intervention for a long time could remarkably improve their clinical prognosis of the elderly patients with isolated systolic hypertension.

Aged↗
PubMed2001

[Effects of exposure to low-level benzene and its analogues on reproductive hormone secretion in female workers].

OBJECTIVE: To study the effects of exposure to low level of mixed benzene on reproductive hormone secretion during menstrual cycle in female workers. METHODS: Concentrations of benzene, toluene and xylene in the expiratory air of 50 exposed female workers from their breathing zone were determined with gas chromatography. Their menstrual cycles of 50 exposed workers and 35 internal control and 35 external control workers were studied prospectively. Urine pregnandiol-3-glucuronide (PdG), follicle stimulating hormone (FSH) and estrone conjugate (E1C) were measured by enzyme immunoassay. RESULTS: Mixed benzene existed mainly in the form of low-level benzene in the air of workplaces, with a detection rate of 29.10% at an average level of 8.88 (0.90-876.47) mg/m3, and 21% of measurements exceeded the national maximum allowable concentration with the highest one as 20.91 folds high as that of the national hygienic standard. Length of luteal phase in the exposed group (13.7 +/- 1.5) days was significantly shorter than that in the internal and external control groups (14.5 +/- 1.2) days and (15.2 +/- 1.1) days (P < 0.05 or P < 0.01). Urine level of E1C before ovulation, that of FSH at early follicular phase and that of PdG in luteal phase after ovulation in the exposed group were significantly lower than those in the internal control group (P < 0.05 or P < 0.01). CONCLUSION: Exposure to low level of mixed benzene in workspaces could interrupt the function of hypothalamic-pituitary-ovarian axis and affect their normal levels of FSH, PdG and E1C.

Adult↗
PubMed2001

[Chemical characteristics of fresh snow in Mount Everest Region].

The chemistry of fresh snow samples collected in August and September, 1998 from Mount Everest was studied and compared with other fresh snow samples collected in different seasons in this region. The results indicated that major species in precipitation were very low in late summer in Mount Everest region and may be representative of the background of precipitation chemistry of remote regions in the wold. Chemical Characteristics of fresh snow in different seasons had distinct differences and they may reflect different moist source and climatic status. The precipitation in August and September was mainly come from Indian summer monsoon and in April and May it was influenced deeply by the dust of semi-arid and arid regions in central Asia. This indicates the precipitation in this region is climatic sensitively.

Calcium↗
PubMed2001

[Multimedia environmental behavior of herbicide atrazine].

In the paper, taking the Baiyangdiang Lake area as a study field, on the basis of soil characterization, environmental monitoring, and studies of adsorption, biodegradation, hydrolysis and photolysis, the atrazine concentrations in soil, groundwater and corn plant during 30 years were predicted by multimedia environmental fugacity model.

Adsorption↗
PubMed2001

[Detection of TORCH genom in the cardiac tissue of congenital heart disease].

OBJECTIVE: To explore relationships of TORCH (cytomegalovirus/CMV, toxoplasma/TOX, rubella virus/RV, herpes simplex virus-2 HSV2) infection with congenital heart disease (CHD). METHODS: We conducted comparison to detection TORCH pathogenic gene in 42 cases of CHD and 38 controls by polymerase chain reaction (PCR). RESULTS: 1. The positive rate of CMV, HSV2 and TOX in 66 cases of CHD were 26.2%, 4.7% and 16.7%, respectively, while those of 38 cases in control groups were 21.1%, 2.6% and 2.6%, respectively. The infection condition of TOX was significantly different (P = 0.0378), while those of CMV and HSV were not statistically different (P > 0.05) between CHD and control groups. 2. 7 of 30(23.3%) were positive for RV-RNA, compared with control group which were all negative, it was significantly higher (P = 0.0328). CONCLUSION: This is the first report of the presence of TORCH genes in CHD cardiac tissue by PCR. It might lay the foundation for studying the relationship of TORCH infection with CHD in molecular level.

Animals↗
PubMed2001

[A biomechanical model of human knee-joint elastic articulate contact].

In this paper, based on the characterizations of human knee-joint anatomical structures and reports of the literature and experiments, a biomechanical model of the human knee-joint elastic articulate contact is developed under the conditions of sampling the human knee-joints. This model is believed to be a powerful tool for functional analysis of the knee, for evaluation of surgical and diagnostic procedures and for design of artificial joints.

Elasticity↗