2001 Vol. 14, No. 3
2001, 14(3): 171-179.
Objective To test the effect of hypothermia on Na+/H+ exchange, activated by shrinkage and cytoplasmic acidosis. Method Amiloride-sensitive Na+ influx in guinea pig red cells was traced with isotope 22Na and intracellular Na+ concentration was measured by emission flame photometry. Result Amiloride-sensitive Na+ influx decreased linearly as a function of temperatures (about 37℃) in shrunken cells, but increased in acidified cells. The up-regulation of acid-induced Na+／H+ exchange by elevated temperature was enhanced by hypo-osmolarity. Less sensitivity of intracellular H+ site at 41℃ may be the mechanism for the inhibition of shrinkage-induced Na+/H+ exchange by elevated temperature. Heating-mediated explosive increase in the activity of acid-induced Na+/H+ exchange may be due to enhanced extracellular Na+ sensitivity and lower intracellular pH caused by acidic metabolites. Acid-induced Na+/H+ ewxchange contributes to cytoplasmic Na+ accumulation. Conclusion These two modes of Na+/H+ exchange with different response to elevated temperature may play different roles in the cellular pathogenesis of heatstroke.
2001, 14(3): 180-188.
Objective In order to study the relationship between alcohol abuse and oxidative stress, and to identify oxidative damage of alcohol abuse in human bodies. Methods 80 cases of male alcoholics (AL) aged 40 years old and 80 cases of male healthy volunteers (HV) of the same age without drinking history were investigated by measuring concentrations of vitamin C (VC), vitamin E (VE) and β-carotene (β-CAR) in plasma as well as activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in RBC with spectrophotometric assays. Results Compared with the average values (AV) of the above biochemical parameters in the HV group, the average values of VC, VE and β-CAR in plasma and the activities of SOD, CAT and GSH-Px in RBC in the AL group were significantly decreased (P = 0.0000). The findings in linear regression and correlation analysis for 80 alcoholics showed that with the prolonged drinking duration and increased daily drinking quantity, the values of VC, VE and β-CAR in plasma as well as SOD, CAT and GSH-Px in RBC in the alcoholics were gradually decreased (P = 0.000), representing a respectively significant linear negative correlation. The analysis of stepwise regression and correlation revealed that the drinking duration had the closest correlation with the values of VE in plasma as well as CAT and GSH-Px in RBC, while the daily drinking quantity had the closest correlation with the values of VC, VE and β-CAR in plasma as well as SOD and GSH-Px in RBC. Conclusion The findings of the present study suggested that the oxidative stress in the alcoholics became pathologically intensified, leading to potential oxidative damages in their bodies. Therefore, alcoholics should abstain from alcohol drinking, and should take as supplements suitable dosage of antioxidants per day such as VC, VE, β-CAR and others to moderate potential oxidative damages in their bodies.
Low Cholesterol in Erythrocyte Membranes and High Lipoperoxides in Erythrocytes Are the Potential Risk Factors for Cerebral Hemorrhagic Stroke in Human
2001, 14(3): 189-198.
Objective To explore the association of risk for human cerebral hemorrhage with blood cholesterol, free radicals, oxidatation and lipoperoxidation. Methods 351 cerebral hemorrhage patients (CHP) in the acute phase and 100 healthy adult volunteers (HAV) were investigated by testing the contents of cholesterol (CH), lipoperoxides (LPO), nitric oxide (NO), vitamin C (VC) and vitamin E (VE) and activities of superoxide dismutase (SOD) in plasma and erythrocytes (RBC), and by assessing the contents of CH and LPO in RBC with spectrophotometric assays. Results Compared with the average values (AV) of the above biochemical parameters (BP) in the HAV group, the AV of CH in plasma and RBC, VC and VE in plasma as well as SOD in plasma and RBC in the CHP group were significantly decreased (P=0.0000), while the AV of the LPO in plasma and RBC as well as NO in plasma in the CHP group were significantly increased (P=0.0000). The findings of linear correlation analysis for the CHP group showed that the above biochemical parameters were significantly correlated with both intracranial hemorrhagic sizes (IHS) and neurotic functional defective scales (NDS). The findings of stepwise correlation analysis for the CHA group suggested that HIS was closely correlated with the values of CH and LPO in RBC as well as NO and VE in plasma, and that NDS was closely correlated with the values of CH and LPO in RBC as well as NO and VC in plasma. Conclusions The findings of the present study suggest that marked low RBC cholesterol and marked high RBC lipoperoxides may constitute the potential main risk factors for human cerebral hemorrhage, and that the oxidative and lipoperoxidative stress in the CHP bodies is pathologically aggravated, leaeing to the oxidative and lipoperoxidative damages in the CHP.
Chromium(VI)-induced Production of Reactive Oxygen Species, Change of Plasma Membrane Potential and Dissipation of Mitochondria Membrane Potential in Chinese Hamster Lung Cell Cultures
2001, 14(3): 199-206.
Objective To examine whether Reactive Oxygen Species (ROS) is generated, and whether plasma membrane potential and mitochondrial membrane potential are depolarized in Chinese Hamster Lung (CHL) cell lines exposed to Cr (VI). Methods CHL cells were incubated with Cr(VI) at 10 μmol/L, 2.5 μmol/L, 0.65 μmol/L for 3 and 6 hours, respectively. The production of ROS was performed by using 2,7_dichlorofluorescin diacetate; The changes in plasma membrane potential were estimated using fluorescent cationic dye DiBAC4; And the changes in mitochondria membrane potential were estimated using fluorescent dye Rhodamine 123. Results The ROS levels in CHL cells increased in all treated groups compared with the control group (P<0.01); The plasma membrane potential and mitochondrial membrane potential in CHL cells dissipated after incubated with Cr(VI) at 10 μmol/L for 3 hours and 6 hours (P<0.01), at 2.5 μmol/L for 6 hours (P<0.01 or 0.05). Conclusion Cr(VI) causes the dissipation of plasma membrane potential and mitochondrial membrane potential in CHL cell cultures, and Cr(VI)_induced ROS may play a role in the injuries.
2001, 14(3): 207-213.
Objective The objective of the study was to evaluate toxicity, anti_stress activity and hepato_protective properties of Kombucha tea. Method Kombucha tea was fed orally for 15 days using three different doses i.e. normal dose, five and ten times the dose. Rats were then sacrificed and various biochemical, and histological parameters were estimated. Anti_stress activity was evaluated either by 1) by exposing animals to cold and hypoxia and estimating the levels of malondialdehyde and reduced glutathione in plasma/ blood or 2) by subjecting the animals to restraint stress and recording faecal output. Hepato_toxicity was induced by challenging the animals to an acute dose of paracetamol (1 gm/kg) orally and determining the plasma levels of SGPT, SGOT and MDA. Results The effect of oral administration of different doses of K_tea to albino rats was examined and the results indicate that K_tea has no significant toxicity as revealed by various biochemical and histopathological parameters. K_tea has been found to prevent lipid peroxidation and fall in reduced glutathione level when rats were exposed to cold and hypoxia in simulated chamber. Further, K_tea has also been found to decrease the Wrap_restraint faecal pellet output in rats. K_tea has also been found to decrease paracetamol induced hepatotoxicity significantly. Conclusion The study shows that K_tea has anti_stress and hepato_protective activities.
2001, 14(3): 214-219.
Objective To validate the use of Allium sativum as a reliable test model for genotoxicity, isoproturon, a substituted phenylalkylurea herbicide, was evaluated on the root meristem cells by this plant system. Method Test concentrations were selected by determining EC50 and root tips were exposed to various concentrations for 6 or 24 hr. EC50 concentration was calculated to be 70.8 ppm for the root growth. In addition to root growth retardation exposure to isoproturon induced morpholoogical changes like discolouration and stiffness of roots. Results Exposure to various experimental concentrations of isoproturon (35-280 ppm), including EC50, significantly and dose-dependently inhibited the mitotic index and induced chromosome breaks/mitotic aberrations at 6 or 24 hr. Conclusion The frequency of aberrations was found to be decreased in a dose dependant manner at 24 or 48 hr post exposure, however in comparison of control cells the frequency of aberrations was considerably high which indicates genotoxicity potentials of isoproturon. Further, present study also suggests that Allium sativum is a sensitive, efficient, and reliable test system for measuring the genotoxicity potential of environmental chemicals.
Ameliorated Chrysotile-induced DNA Damage in Human Embryo Lung Cells by Surface Modification of Chrysotile With Rare Earth Compounds
2001, 14(3): 220-228.
Objective In view of the fact that asbestos is not only a key occupational hazard, but also an important environmental pollutant, it is necessary to develop a proper method to decrease the carcinogenecity of asbestos fibers. This study was designed to determine if the surface modification of chrysotile asbestos fiber (CAF) with rare earth compounds (REC) can ameliorate CAF-induced DNA damages in human embryo lung (HEL) cells. Methods After incubation with REC solution at different concentrations at room temperature for 1 h, natural and REC-pretreated CAF was added to cell culture at various doses. At the selected time as the experiment designed, DNA damages of the HEL cells were detected by Unscheduled DNA Synthesis (UDS) and Single Cell Gel Electrophoresis (SCGE) assays. Results The UDS induced by natural CAF was elevated with the increase of CAF doses. There was a good dose-response relationship between the UDS and the amount of CAF in the medium and the coefficient of correlation (R) was 0.958 at P<0.05. In REC-pretreated CAF groups, the UDS declined with the increase of REC doses. Both catalase (CAT) and dimethylsulfoxide (DMSO) also reduced the CAF-induced enhancement of UDS. In SCGE assay, CAF induced DNA chain breakage and the magnitude of DNA chain breakage increased in a dose-dependent manner and the coefficient of correlation (R) was 0.992 at p<0.01, while REC-pretreated CAF significantly decreased the induction of DNA chain breakage in a dose-dependent manner(r=0.989, p<0.05). Conclusion It can be concluded that CAF-induced DNA damages in HEL cells may be partly mediated by oxygen derivatives, and the surface modification of CAF with REC might hide critical sites on the fiber surface, thereby reducing the fiber-mediated production of oxygen derivation and lowering the CAF-induced UDS and DNA chain breakage in HEL cells.
Eye Irritation Caused by Formaldehyde as an Indoor Air Pollution——A Controlled Human Exposure Experiment
2001, 14(3): 229-236.
Obejective The present study focuses on health assessment of wood based panels which are widely used in interior decoration practices over the recent years in China. Formaldehyde has been identified as chemical indicator of (IAO) and an indoor air pollutant. To test its health effects experiment was undertaken. Method A small environmental test chamber (60/L) was used as the generator of emission gas from new panels, and was operating at a temperature of 22.7±0.6℃ and a humidity of 44.4±2.5 % with an air exchange rate of 1.0±0.15h-1. On the three experimental days the values of product loading in chamber were 4, 2 and 6 m2/m3, respectively. Eight people were selected randomly from the students and employees of Wuhan Health and Anti-epidemic Station as subjects, with an average age of 21.9±5.9 years, and a gender ratio of 1:1, and two of them were smokers (one male and one female). The subjects' eyes were exposed to formaldehyde through a pair of goggles. Each goggle had its flow inlet and outlet, and connected to chamber exhaust of emission gas and to an exhaust from the room. The exposure time was very short, just 5 minutes and the formaldehyde doses were at 1.65±0.01, 2.99±0.07 and 4.31±0.02 ppm. A 60-mm linear visual analogue rating scales was used to measure the intensity of sensory eye irritation and a video tape recorder was used to record eye blinking frequency. Results The results demonstrated that tests of sensory eye irritation and eye blinking can be used for materials testing, and that a dose-effect as well as a time-variance of the effect can be measured. Conclusion The tests showed that eye irritation was perceived at all of the three levels.
2001, 14(3): 237-240.
Objective Localization of the glutathione dependent Nitroblue tetrazolium (NBT) reductase in fresh frozen sections of mouse skin and possible dependence of NBT reductase on tissue thiol levels has been investigated. Methods The fresh frozen tissue sections (8m thickness) were prepared and incubated in medium containing NBT, reduced glutathione (GSH) and phosphate buffer. The staining for GSH was performed with mercury orange. Results The activity of the NBT-reductase in mouse skin has been found to be localized in the areas rich in glutathione and actively proliferating area of the skin. Conclusion The activity of the NBT-reductase seems to be dependent on the glutathione contents.
2001, 14(3): 241-247.
Objective The purpose of this study is to investigate the effect of superoxide anion on the apoptosis of cultured fibroblasts and the protective role of selenium and Vitamin E. Methods Cultured fibroblasts (NIH3T3), with or without selenium or vitamin E in the medium, were treated by superoxide anion produced by xanthine/xanthine oxidase reaction system and changes in cell structure and DNA were observed microscopically and electrophoretically. Results Apoptosis was observed when superoxide anion at a concentration of 5 nmol/L or 10 nmol/L had acted on the fibroblasts for 5-10 h. Selenium and Vitamin E in the medium inhibited the apoptosis significantly when their concentrations reached 1.15 mol/L and 2.3 mol/L respectively. Conclusion Selenium and vitamin E have protective effect against the apoptosis induced by superoxide anion. The effect of selenium is more remarkable than that of vitamin E.
2001, 14(3): 248-255.
Objective Effects of low dose radiation on signal transduction of neurons in mouse hypothalamus were investigated. Methods In the present study competitive protein binding assay, radioimmunoassay, in situ hybridization and immunohistochemistry were used to observe the effects of whole-body irradiation with 75 mGy X-rays on the contents of cAMP and cGMP and the expressions of c-fos mRNA, Fos protein and proopiomelanocortin (POMC) mRNA in the neurons of mouse hypothalamus. Results The results showed that cAMP content in mouse hypothalamus immediately increased significantly and reached the peak value in 15 min after irradiation, and then returned to near sham-irradiation level 1 h after irradiation, followed by a small fluctuation of increase and decrease; the changes of cGMP content were basically opposite to those of cAMP content, while the changes of cAMP/cGMP ratio were basically consistent with those of cAMP content. The expression of c-fos mRNA in the neurons of hypothalamus appeared 15 min after irradiation, reached its peak value within 1 h, began to abate 2 h with its total disappearance 8 h after irradiation; the expression of Fos protein reached its peak value 8 h after irradiation, and then gradually returned to sham-irradiation level 48 h after irradiation; the expression of POMC mRNA decreased significantly 1 h after irradiation and remained at a lower level in the observation period of 12 h. Conclusion These findings implicate that low dose radiation may potentiate the activity of the neurons in mouse hypothalamus, expedite their signal transduction, and down-regulate the functions of hypothalamus-pituitary-adrenocortical axis.