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Biomedical subjects

G H Yang

Publications and source records attributed to G H Yang.

At least 19 recordsLinked to original sources

Inducible nitric oxide synthase expression and nuclear factor-kappaB activation in alveolar type II cells in lung injury.

Alveolar type II cells (type II cells) play a crucial role in the progression and repair of lung inflammation and injury. We investigated whether inducible nitric oxide synthase (iNOS) was expressed and nuclear factor-kappaB (NF-kappaB) was activated in type II cells in lung injury. After injecting lipopolysaccharide (LPS) or saline in the rat, the lungs were excised and type II cells were isolated. iNOS and its mRNA were expressed both in lung tissue and isolated type II cells in response to LPS. The lungs from saline-treated rats showed only minimal expression of iNOS. Electrophoretic mobility shift assay revealed that expression of NF-kappaB in the nuclear extracts was augmented by LPS, and p5O/NFkappaB was expressed in type II cells in LPS-treated rats. Intraperitoneal dexamethasone almost completely inhibited the iNOS expression and attenuated the activation of NF-kappaB in the LPS-treated lung. These findings suggest that type II cells can be a source of NO production in lung injury,and that the effects of corticosteroids may be in part through inhibition of both iNOS expression and NF-kappaB activation.

Animals↗

[Effects of simulated weightlessness on T cell subpopulations and activity of IL-2 and IL-6 in mice].

OBJECTIVE: To observe the effects of simulated weightlessness on the immunogenic activities in mice. METHOD: T cell subpopulations and the activity of IL-2 and IL-6 were observed in mice after exposure to head-down (-30 degrees) tail suspension for 3 d and 7 d. RESULT: The activity of IL-2 and IL-6 in mice showed no change after simulated weightlessness for 3 d compared with the control group. But after simulated weightlessness for 7 d, CD3+ and CD4+ were markedly reduced (both P< 0.01) and CD8+ and CD4+/CD8+ also tended to decrease; the activity of IL-2 was significantly decreased, while the activity of IL-6 tended to increase. CONCLUSION: Simulated weightlessness for 7 d had significant effects on T cell subpopulations and the activity of certain cytokines in mice.

Animals↗

[A study on quality standard of Sambucus chinensis Lindl].

OBJECTIVE: To offer evidences for exploiting the plant resources and drafting the quality standards. METHOD: Studies of pharmacognosy. RESULT: The medicinal properties and the microscopic characteristics of the stem, leaves, rhizome and powder were described, drawn and physicochemically identified. CONCLUSION: A convenient and effective method for identifying the herb has been established.

Plant Leaves↗

Apoptosis induction by the satratoxins and other trichothecene mycotoxins: relationship to ERK, p38 MAPK, and SAPK/JNK activation.

The satratoxins are members of the trichothecene mycotoxin family that are produced by the fungus Stachybotrys and that have been etiologically associated with building-related health problems. The purpose of this study was to relate cytotoxic and apoptotic capacities of satratoxins and other trichothecenes to the activation of three groups of mitogen-activated protein kinases (MAPKs) (extracellular signal-regulated protein kinase (ERK), p38 MAPK, and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK)). Two myeloid models, RAW 264.7 murine macrophage and U937 human leukemic cells were used. Upon evaluating representative trichothecenes in the 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) cleavage assay, cytotoxicity was evident according to the following rank order: satratoxin G, roridin A, and verrucarin A > T-2 toxin, satratoxin F, H > nivalenol, and vomitoxin. Comparable results were found when measuring trichothecene-mediated apoptosis using DNA fragmentation and fluorescence microscopy assays, thus suggesting that cytotoxicity was mediated through an apoptotic process. Assessment of MAPK activation using Western blot analysis revealed that trichothecenes activated not only SAPK/JNK and p38 MAPK but also ERK. Activation of MAPKs by satratoxins and other trichothecenes correlated with and preceded apoptosis. The concentration of satratoxin G sufficient for protein synthesis inhibition correlated with that required for apoptosis and activation of all three MAPKs. Cycloheximide had similar effects to trichothecenes, suggesting that ribosome binding or protein synthesis inhibition may play roles in MAPK activation and apoptosis induction. Apoptosis induction by satratoxin G and vomitoxin was markedly enhanced when ERK activation was selectively inhibited by ERK-specific inhibitor PD98059, thus indicating a negative role for ERK. Inhibition of p38 MAPK activity with the p38-specific inhibitor SB203580 had no effect on apoptosis induction by the highly toxic satratoxin G. However, SB203580 moderately inhibited apoptosis induction by the less toxic trichothecene vomitoxin, thus implying a partial role of p38 MAPK in trichothecene-induced apoptosis. The results suggest that the satratoxins are among the most potent trichothecenes and that MAPKs may play integral roles in the diverse toxic manifestations of these mycotoxins.

Animals↗

Modulation of transcription factor AP-1 activity in murine EL-4 thymoma cells by vomitoxin (deoxynivalenol).

Trichothecene mycotoxins have been reported to suppress or superinduce cytokine mRNA expression by leukocytes both in vitro and in vivo. Modulation of transcription factor activities may be critical for these observations. Here, the effect of trichothecene vomitoxin (VT, deoxynivalenol) on activator protein-1 (AP-1) activity was determined in the murine EL-4 thymoma. Electrophoretic mobility shift assay (EMSA) revealed that VT modulated AP-1 binding activity in a concentration- and time-dependent manner when using a synchronous model in which VT was added concurrently with phorbol 12-myristate 13-acetate (PMA) and ionomycin (ION) to EL-4 cells. Induction of AP-1 binding activity by PMA/ION was suppressed in the presence of VT for a short period (1 to 12 h), but was enhanced upon prolonged VT exposure (48 to 72 h). VT also enhanced AP-1 binding activity when added to the cell culture 12 h after PMA/ION activation (delayed synchronous model). Using specific antibodies against AP-1 complex proteins, it was demonstrated by gel supershift assay that VT preferentially affected phosphorylated c-Jun, Jun B, c-Fos, and Fra-2 binding activities, whereas it did not alter Jun D and Fra-1 binding. A transient transfection assay demonstrated that these increased binding activities are associated with enhanced AP-1 transactivation potential. Elevation of AP-1 activity may contribute to cytokine dysregulation and immunotoxic effects associated with exposure to trichothecene mycotoxins such as VT.

Animals↗

Down-regulation of the endoplasmic reticulum chaperone GRP78/BiP by vomitoxin (Deoxynivalenol).

The mechanisms by which trichothecene mycotoxins cause immunological effects in leukocytes such as cytokine up-regulation, aberrant IgA production, or apoptotic cell death are not fully understood. In the present study, mRNA differential display analysis was used to evaluate changes in gene expression induced by the trichothecene vomitoxin (VT or deoxynivalenol) in a T-cell model, the murine EL-4 thymoma, that was stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin (ION). Ten differentially expressed fragments of cDNA were isolated and sequenced and three of these were identified as the known genes GRP78/BiP, P58(IPK), and RAD17. Most notably, expression of GRP78/BiP (a 78-kDa glucose-regulated protein), a stress-response gene induced by agents or conditions that adversely affect endoplasmic reticulum (ER) function, was found to decrease in VT-exposed cells. Competitive RT-PCR analysis revealed that 250 ng/ml VT decreased GRP78/BiP mRNA expression in both unstimulated and PMA/ION-stimulated EL-4 cells at 6 and 24 h after VT treatment. Western blotting confirmed that VT (50 to 1000 ng/ml) also significantly diminished GRP/BiP protein levels in a dose-response manner in PMA/ION-stimulated cells. GRP78/BiP has been shown to play a role in regulation of protein folding and secretion, and to protect cells from apoptosis. When PMA/ION-stimulated cells were incubated with 50 to 1000 ng/ml VT for 24 h, 200-bp DNA laddering, a hallmark of apoptosis, increased in a dose-dependent manner. In addition to GRP78, mRNA expression of the cochaperone P58(IPK), which is the 58-kDa cellular inhibitor of the double-stranded RNA-regulated protein kinase (PKR), was also shown to be suppressed by VT-treatment. GRP78 and P58(IPK) are critical for maintenance of cell homeostasis and prevention of apoptosis. The down-regulation of these molecular chaperones by VT represent a novel observation and has the potential to impact immune function at multiple levels.

Animals↗

Effects of interleukin-1 beta on DNA synthesis in rat alveolar type II cells in primary culture.

Proliferation of alveolar type II cells is critical for restoration of the integrity of alveolar epithelium in alveolar injuries caused by a number of different aetiologies. Because effects of inflammatory cytokines on the proliferation of alveolar type II cells are not clear, we investigated the effects of interleukin-1 beta (IL-1 beta) on [3H]-thymidine incorporation into DNA in rat alveolar type II cells in primary culture. Interleukin-1 beta enhanced the [3H]-thymidine incorporation dose and time dependently. The increase of [3H]-thymidine incorporation was observed in parallel with increased number of rat alveolar type II cells. The effect of IL-1 beta on [3H]-thymidine incorporation was additive to effects of growth factors which were known to act as mitogenic factors for type II cells. Anti-interleukin-1 beta antibody or IL-1 receptor antagonist partially inhibited the effects of IL-1 beta on [3H]-thymidine incorporation. Their combination completely inhibited the effects of IL-1 beta. In the absence of IL-1 beta, the combination inhibited the [3H]-thymidine incorporation to a level under that in the control. Isolated alveolar type II cells were immunocytochemically stained positive with anti-IL-1 beta antibody. Reverse transcriptase-polymerase chain reaction (RT-PCR) showed the presence of the mRNA for IL-1 beta in cultured alveolar type II cells. These results demonstrate that exogenous IL-1 beta stimulates DNA synthesis in alveolar type II cells and that the cells also produce IL-1 beta endogenously and suggest that endogenous IL-1 beta may mediate basal DNA synthesis of alveolar type II cells.

Animals↗

[Lung tissue injury caused by oxidant-antioxidant imbalance].

The lung is susceptive to excess oxidants from inhaled air and marginated large portion of circulating leukocytes. Oxygen radicals generated from sequestrated leukocytes injure endothelial cells to increase permeability. Excessively generated oxidants in the mitochondria, such as in ischemia-reperfusion injury, changes mitochondrial function and cause Ca++ leak from the organelle, which leads to induction of apoptosis. Reactive oxygen intermediates induce some cytokine gene expression such as IL-8. Hydrogen peroxide activates phospholipase C and the subsequent signal transduction pathways resulting in change of cytoskeletal configuration and cell shape. It is expected that understanding of contribution of oxidant-antioxidant imbalance in lung diseases may develop new strategy of 'antioxidant' therapies.

Antioxidants↗

Application of YLD calculation in assessing disease data--an analysis of 4 diseases in 2 regions.

The objective of the current study is to discuss the problems related to how data is used to calculate Years Lost with Disability (YLD) with the method recommended by the World Bank. The study includes collecting useful data, estimating disease duration and average age of disease onset, adjusting incidence and prevalence data by means of a software programme, DISMOD (Harvard University Incidence & Prevalence Model), and assessing the importance of YLD calculation for different diseases. Remission and fatality rates of 3 diseases were estimated by experts at 2 round consultations. Incidence rates, disease duration and average age of disease onset were calculated and adjusted by DISMOD. YLD due to schizophrenia is the highest among 4 diseases in two regions. YLD is 18.88% in disability adjusted life year for 4 diseases in Xiacheng District, and 19.97% in Fuyang County. Available data can be used for the calculation of YLD after being adjusted. DISMOD is a useful instrument to test the internal consistency of incidence, prevalence, remission and fatality rate. The adjusted data are acceptable to experts and DISMOD. To get rational remission and fatality rates, we can use a cohort method through expert consultations. To reflect overall burden of disease, YLD calculation should be used.

Accidents, Traffic↗

[Changes of blood circulation, muscle and skeletal systems in 30 d tail-suspended [correction of tail-suspented] rats].

OBJECTIVE: To confirm the tail-suspended rat model for the study of countermeasures against weightlessness. METHOD: The changes of blood circulation, muscle and skeletal systems in control group rats (n = 15) and 30 d tail-suspended rats (n = 15) were compared. RESULT: Compared with the control group, the hemorrheology and erythrocyte deformability decreased significantly, muscle-fiber atrophy, muscle contraction function decreased, the type I muscle fibers transformed to the type II muscle fibers, bone-mineral content of L3 and load capacity of femur declined, bone metabolism changed in the suspended rats. CONCLUSION: The tail-suspended rat is a suitable animal model for the study of countermeasures against weightlessness.

Animals↗

[Effect of -6 degrees head-down-bed-rest on human cellular immune function].

OBJECTIVE: To observe the effect of -6 degrees head-down bed-rest on proliferation of lymphocyte and production of certain cytokines. METHODS: 6 healthy young men served as the subjects. Peripheral blood lymphocyte was assayed 1d prior to and on the 3rd day and 6th day of bed rest. RESULTS: The production of IFN-alpha on the 3rd day was markedly decreased (P < 0.05), but killing activity of NK was significantly enhanced (P < 0.05), production of IFN-gamma and expression of IL-2 receptor were all slightly reduced. Both production of IFN-alpha and killing activity of NK resumed to the control level on the 6th day, production of IFN-r and CD25 were significantly lowered (P < 0.05) on the 6th day, a lymphocyte proliferation and production of IL-2 were gradually decreased with time, but production of IL-6 was gradually increased. CONCLUSION: -6 degrees head-down bed-rested has certain effect on cellular immune function in man.

Adult↗

Emerging tobacco hazards in China: 2. Early mortality results from a prospective study.

OBJECTIVE: To monitor the evolving epidemic of mortality from tobacco in China following the large increase in male cigarette use in recent decades. DESIGN: Prospective study of smoking and mortality starting with 224 500 interviewees who should eventually be followed for some decades. SETTING: 45 nationally representative small urban or rural areas distributed across China. SUBJECTS: Male population aged 40 or over in 1991, of whom about 80% were interviewed about smoking, drinking, and medical history. MAIN OUTCOME MEASURE: Cause specific mortality, initially to 1995 but later to continue, with smoker versus non-smoker risk ratios standardised for area, age, and use of alcohol. RESULTS: 74% were smokers (73% current, only 1% former), but few of this generation would have smoked substantial numbers of cigarettes since early adult life. Overall mortality is increased among smokers (risk ratio 1.19; 95% confidence interval 1.13 to 1.25, P<0.0001). Almost all the increased mortality involved neoplastic, respiratory, or vascular disease. The overall risk ratios currently associated with smoking are less extreme in rural areas (1.26, 1.12, or 1.02 respectively for smokers who started before age 20, at 20-24, or at older ages) than in urban areas (1.73, 1.40, or 1.16 respectively). CONCLUSION: This prospective study and the accompanying retrospective study show that by 1990 smoking was already causing about 12% of Chinese male mortality in middle age. This proportion is predicted to rise to about 33% by 2030. Long term continuation of the prospective study (with periodic resurveys) can monitor the evolution of this epidemic.

Adult↗

Cloning and characterization of the upstream region of Clostridium botulinum type B neurotoxin gene.

The upstream region of the gene coding for Clostridium botulinum type B (BoNT/B) neurotoxin was cloned and sequenced. There were two open reading frames, which were identified as a nontoxic-nonhemagglutinin component (ntnh/B) and a 22 kDa adjacent open reading frame (orf22/B). Deduced primary structure of ntnh/B showed that it was composed of 1,197 amino acid residues. Pairwise comparisons of the ntnh/B component with other botulinum toxin types showed high degree of homology to ntnh/A (82% identity). Northern blot analysis revealed that toxin gene could be transcribed alone or co-transcribed with the ntnh gene. The orf22/B gene encoding for 178 amino acids (M.W. 21.6 kDa) was located between the 33 kDa hemagglutinin gene and the ntnh gene. Orf22/B also showed high degree of homology to orf22/A (98.9% identity). These results suggested that the upstream region of the BoNT/B gene (containing the ntnh/B and orf22/B genes) might be evolutionarily closely related to the counterparts of the BoNT/A.

Amino Acid Sequence↗

Child mortality patterns in rural areas of Anhui and Henan provinces in China, 1990.

County-based IMR and U5MR in Anhui and Henan provinces in China were estimated and analyzed by using the 1990 Census Data. Census was conducted on July 1, 1990, the number of deaths only occurred in the first half year of 1990 was collected. In order to obtain the total population and total number of deaths in the same year, the total number of deaths in each age-sex group for the whole 1990 was then estimated by taking the death number in the first half of 1990 as the base and multiplying a coefficient, which varied in different age-sex-region groups. Two major adjustments for some possible under-reporting cases in female birth and infant death were made. If the sex ratio at age 0 in some counties was beyond 1.2, then it was taken as 1.15 for rural counties and 1.10 for urban cities, which were the estimates of sex ratios for the children at age 5 in the national 1% Population Sampling Survey in 1995. The adjustment for IMR were made by comparing the segment of the county lift table from age 15 through 59 with that from the same age groups in the international and Chinese Model Life Tables. The IMR in the county life table would be substituted by the one in the closest Model Life Talbe, if it was less than in the latter. The findings of the analysis may be summarized as follows: (i) Total county-based IMR and U5MR were 33.4 per 1,000 and 41.4 per 1,000 respectively, with great variations between urban cities (25.4 per 1,000 for IMR and 31.4 per 1,000 for U5MR) and rural counties (35.1 per 1,000 for IMR and 43.6 per 1,000 for U5MR). There were also significant differences in child mortality between nationally identified poor counties and other counties in rural areas. In the poor counties the total IMR was 40.7 per 1,000 living births in average while in non-poor counties it was only 33.2 per 1,000 in average (P < 0.05). The U5MR in poor counties was 25 percent higher than in non-poor counties (51.5 vs 40.9 per 1,000 living births). (ii) Statistically significant correlation between child mortality and socio-economic variables was revealed from the data set, among which gross social economic products per capita was found to have the strongest relationship with child mortality. The negative correlation was found between child mortality and a set of so-called 'rich' variables including the gross social products, gross agricultural products, gross industrial products and the proportions of high-educated population at county level, whereas the positive correlation was found between child mortality and a set of 'poor' variables, such as proportions of residents with lower level of education and illiteracy rate. (iii) Differences in child mortality between these two provinces were found, which were identical to the trends of differences in socio-economic indicators between them. Lower child mortality proved to be associated with better socio-economic conditions (higher per capita products, higher proportions of residents with higher level of education, lower proportion of less educated people and illiteracy) in province Henan. (iv) A simple linear regression model was developed separately for Henan and Anhui to predict the IMR and U5MRs in each stage of economic development, where the dependent variables were the logarithm of IMR and U5MR, and the independent variables were the quintiles of the output value of gross products (GOP). It was found that at the first quintile, which was equivalent to 800 yuan of GOP in average, the predicted IMR and U5MR would reach 40 per 1,000 and 51 per 1,000 respectively. It would decline to 38 per 1,000 for IMR and 47 per 1,000 for U5MR in the second lowest quintile. Dramatic drop of child mortality was found between the second quintile and the third quintile, where 6 per 1,000 decline would occur for both IMR and U5MR. The decline would continue subsequently, but slower. The prediction of child mortality in rural counties could be used as a reference to assess counties at different stages of socio-

Adolescent↗

Cleavage of the synaptobrevin/vesicle-associated membrane protein (VAMP) of the mouse brain by the recombinant light chain of Clostridium botulinum type B toxin.

The light chain of Clostridium botulinum type B toxin was expressed in Escherichia coli using the expression vector pEt-3a containing phage T7 promoter. The expressed protein was then purified by DEAE-cellulose and phosphocellulose chromatography and the proteolytic activity of the purified light chain was studied. The purified recombinant light chain cleaved synaptobrevin when mixed with the mouse brain microsome and the proteolytic activity of the light chain was inhibited if a metal chelating agent such as EDTA or 2,2'-dipyridyl was added. The recombinant light chain cleaved synaptobrevin more effectively than the native type B toxin. When the native toxin was trypinized and was reduced with DTT, its proteolytic activity was similar to that of the recombinant light chain.

2,2'-Dipyridyl↗

Effect of topical aclacinomycin on glaucoma filtration surgery in rabbits.

A prospective, randomized, double-masked and placebo-controlled study was performed to compare the effects of a single 5-minute intraoperative exposure to aclacinomycin (AMC) 0.4 mg/ml or 0.8 mg/ml with control eyes treated with saline solution on the success of glaucoma filtration surgery in 26 rabbits. Intraocular pressure (IOP), bleb survival, fistula patency and complications were evaluated. The results showed that IOP in the eyes treated with AMC was significantly lower than that in the control eyes from days 5-40 in the 0.4 mg/ml group and from days 5-20 in the 0.8 mg/ml group. The bleb survival lasted significantly longer in the two treated groups than in the control group and in the AMC 0.4 mg/ml group than in the AMC 0.8 mg/ml group. At 40 days, the rate of sclera fistula occlusion was 0% in the AMC 0.4 mg/ml eyes, 43.8% in the AMC 0.8 mg/ml eyes, and 100% in the control eyes. Significant complications, such as anterior chamber inflammation, hyphema, moderate and severe corneal haze, dense corneal neovascularization and mild cataract occurred only in the eyes treated with AMC 0.8 mg/ml. The results indicated that intraocular treatment with AMC at a dose of 0.4 mg/ml had a markedly beneficial effect on IOP, bleb appearance and fistula patency after experimental filtration surgery in rabbits.

Aclarubicin↗

National public health surveillance in China: implications for public health in China and the United States.

STUDY OBJECTIVE: Throughout the world, political developments have brought new demands to communities to prevent and intervene in the incidence of infectious and noninfectious conditions. Historically, these developments have required new and more effective public health surveillance activities. This report describes public health surveillance practice in the People's Republic of China, making comparisons with selected aspects of surveillance in the United States with respect to collection, analysis, dissemination, and use of data. MAIN RESULTS: In both the People's Republic of China and the United States, political change has affected health, and multiple surveillance system are used in public health practice. Surveillance of acute infectious diseases based on the reporting of legally notifiable diseases and the use of vital records for surveillance have the longest established history in both countries. In both countries, data from the surveillance systems have been used to affect public health policy. CONCLUSIONS: In comparing surveillance practices in these countries, we find similarities in conditions reported and in the dissemination of the data. At the same time, legal, social, cultural, and economic differences between the nations have affected the practice of surveillance in analysis and evaluation. We make explicit recommendations for improvement and evaluation of systems in both countries, including sentinel surveillance system and data quality measures in China and computer networking and data analysis in the United States.

Centers for Disease Control and Prevention, U.S.↗

[Level and trend on injuries among Chinese population].

In this paper, epidemiological distribution and trend on injuries of Chinese population are described, and at the same time, characters and proportion of injuries to the total deaths are analyzed according to data in National Disease Surveillance Point system (DSP). Some important injuries and variance in population by different sexes, age groups and places are analyzed in detail. The death rate on suicide of Chinese population is high, reaching 19.58/10(5). The rate of suicide among females is higher than males, especially in female population of 20-34 age group, proportion is 46.70% to female total suicide. Rate of suicide of old people is also very high, population of over 60 years olds. It counts 29.72% to the total. The death rate due to transportation is going up, from 9.82/10(5) in 1991 to 14.32/10(5) in 1995, with an annual average incseasing ratio 7.84%. Drowning is the major cause of injuries for children of 0-14 years old, proportion of their death is 56.56% to the total death of drowning, 46.48% among them is children of 1-4 years old.

Accidents, Traffic↗