Biomedical subjects

G Huang

Publications and source records attributed to G Huang.

At least 91 records · Page 5Linked to original sources

PubMed2000

[Cost-effectiveness analysis of Beijing Fangshan cardiovascular prevention program in 1992 - 1997].

OBJECTIVE: To determine whether a community-based cardiovascular disease (CVD) intervention program, undertaken over six years, was cost-effective. METHODS: Based on Beijing Fangshan Cardiovascular Disease Comprehensive Prevention Program, the cost for intervention and expenditure saved from caring for CVD in the communities with intervention from 1992 to 1997 were calculated, and cost-effectiveness analysis was performed using disability-adjusted life years (DALYs) gained as an indicator of effectiveness. RESULTS: The cost for one DALY gained reduced gradually from 1992 to 1997, with an average ratio of cost to effectiveness of four to one (4:1). It cost annually 1,586.00, 1,380.20, -2,350.80, -905.30, -1,495.60 and -1,766.70 RMB yuan for one life-year saved, from 1992 to 1997 respectively, in a gradually decreasing trend with the increase in length of intervention. After intervention for two years, ratio of cost to effectiveness has become negative since 1994, which meant a positive benefit from intervention. Sensitivity analysis showed that ratio of cost to effectiveness was little sensitive to the changes in discount rate, weight of age and increase in cost of hospitalization for stroke and coronary heart disease, which reflected its reliability. CONCLUSION: Community-based comprehensive intervention for CVD in rural population is cost-effective.

Aged↗

PubMed2000

[Toxic effects of aluminum on human embryonic cerebral neurocytes in vitro studies].

OBJECTIVE: To study the toxic effect of aluminum on human embryonic cerebral neurocytes in vitro studies. METHODS: Human embryonic cerebral neurocytes were divided into three groups (control, low Al and high Al groups). The growth, development and morphology of neurocytes were observed by light and electron microscopy. The protein, DNA, lipid peroxide (LPO) contents and the activity of neuron-specific enolase (NSE) and cholinesterase (CHE) of neurocytes were detected. RESULTS: The number of viable cells in high Al group was significantly lower than that in the control group (P < 0.05). The number of swelling, degenerated and necrotic cells was significantly increased in high Al group. The DNA content and the activity of NSE and CHE of neurocytes were significantly decreased with the increase of Al concentrations (P < 0.05). The LPO content of neurocytes in the high Al group was significantly higher than that in the control group (P < 0.05). There was a positive correlation between the Al dose and LPO content of neurocytes (P < 0.05). The electron microscopy study showed that the membrane structure of cell was damaged in the high Al group and the arrangement of microtubules in the processes was disordered. CONCLUSIONS: The growth, development and function of human embryonic cerebral neurocytes was inhibited in the high Al group. The neurotoxicity of Al may be caused by lipid peroxidation and the damage of cell membrane.

Aluminum↗

PubMed2000

[A study on incidence of injury and its socio-economic loss in children and young adults].

OBJECTIVES: To study the current status of incidence of injury among children and young adults and the causes of common injuries, and to estimate its socio-economic loss and extent of harmfulness. METHODS: Pupils in 19 primary and middle schools aged 7 to 18 years, totaling 14,533, were recruited with stratified cluster sampling during 1998 to 1999 in Guangzhou, Maoming, Jiangmen and Shantou. Judgement for injury was based on the following criteria: (1) diagnosed and treated in hospitals or school clinics, (2) a half-day off or more due to injury, and (3) emergency management by pupils' parents or teachers. RESULTS: There were 6 941 pupils suffered from varied injures during the year, with an incidence rate of 47.76% (50.08% for boys and 45.02% for girls). Incidence rate of injury was higher in the middle school pupils (13 - 18 years old, 58.49%) than that in the primary school pupils (7 - 12 years old, 40.08%). The incidence increased significantly with age, with a peak at ages of 13 - 15. Major causes of injuries resulted from falls, injury by sharp articles, collision, traffic injuries and burn/scalds, etc, which usually occurred due to carelessness in sports, playing, walking, bike-riding and working. Frequency of multiple injuries related to the educational level of parents and depended on whether or not an only-child in family. There were 2,173 injured pupils (accounting for 31.3% of the total) visited clinics or emergency department in hospitals and 627 (9.0%) hospitalized for treatment. Twenty-eight percent of the injured pupils were absent from school, with an average absenteeism of 5.6 days. There were 154 injured pupils with transient disability and 53 with permanent disability, with a disability rate of 410.47 per 100,000. Cost for their medical care averaged 81.5 yuan RMB per injured pupil. CONCLUSIONS: Injury was a common and frequently-happened incident among children and young adults and could seriously affect their health, development and growth, studying and their future of children and young adults. Health education, safety-promotion and removing hidden danger for injury are the major measures to prevent from injury, and the government and the whole society should pay great attention to injury issues in children and young adults.

Accidents↗

PubMed2000

[Effects of methyl tertiary butyl ether on cell cycle and cell apoptosis].

OBJECTIVE: To explore the effects of the new gasoline additive, methyl tertiary butyl ether (MTBE) on cell cycle and cell apoptosis. METHODS: Flow cytometry was used to evaluate the effect of MTBE (1, 2, 4 microl/ml, 24 h) on NIH/3T3 cell cycles; and the effect of MTBE on Hela cell apoptosis was evaluated by detecting cell survival using crystal violet staining. RESULTS: Flow cytometry showed that MTBE could change NIH/3T3 cell cycles, decrease the number of cells in S stage, and arrest cells at G(2) + M stage. The results suggested that MTBE could affect NIH/3T3 cell cycles and induce cell proliferation. This situation existed 48 hours after the treatment, and cell cycles came back normal 96 hours after the treatment. By detecting cell survival using crystal violet staining, we found that MTBE could inhibit the apoptosis of Hela cells which was induced by tumor necrosis factor (TNF)alpha and cycloheximide. CONCLUSION: MTBE's carcinogenicity to animals may relate to induction of cell proliferation and inhibition of cell apoptosis.

3T3 Cells↗

PubMed2000

[Tangent time constant and wave-speed mechanism of F-V curve configuration in smokers and clinical significance].

This study was conducted to explore the mechanical mechanism of the formation of F-V curve configuration with tangent time constant (tau 1) and wave-speed theory for smokers. F-V curves were measured on 22 passive smokers and 94 active ones. FVC, V75, V50 and V25 were obtained, and tangent time constants at high, mid, low lung volumes, tau t75, tau t50 and tau t25 were calculated, and analysed with wave-speed theory. The results showed that the chief changes taking place only in heavy smokers and convex type of F-V curve were: decreased V50 and V25; tau t25 > or = 1s; tau t75-tau t50 < tau t25 in "trumpet fashion" change; and tau t75 < tau t50 < tau t25 in "tower fashion" change. Then, tau t25 > or = 1s, tau t75-tau t50 < tau t25 and tau t75 < tau t50 < tau t25 were assigned as three tau t characters of smoking effect. They led to an increased convexity of the convex type of F-V curve, and reflected the decrease of small airway functions. Similar to the decrease of V50 and V25, they have important significance in assessing small airway functions and thus merit clinical use.

Adult↗

PubMed2000

[Relationship of p53 gene mutation with pathological characteristics and prognosis of thyroid carcinoma].

This study was directed to the role of p53 gene in the carcinogenesis of thyroid carcinomas and to the correlation between p53 gene and the clinicopathological characteristics of the cancer. Single-stranded conformation polymorphism of PCR was used in detecting p53 gene point mutations in exons 7, 8. The result showed that ten of thirty-one thyroid carcinomas had mutations in exons 7 and 8 (32.3%). The frequency of p53 gene mutations was significantly higher in relapse group than in no relapse group (P < 0.01). No statistically significant differences in p53 mutation were found relating to metastasis, histological type and differentiation (P > 0.05). These data suggest that the mutation of p53 gene may play an important role in thyroid carcinoma and the mutations of p53 gene be associated with the prognosis of thyroid carcinoma.

Adenocarcinoma, Follicular↗

PubMed2000

[Configurations of F-V curve and their transformation rule in COPD patients analysed with wave-speed theory].

This study sought to analyse the mechanism on the formation of configurations of F-V curve and their transformation rule in COPD and cor pulmonale patients with wave-speed theory. The F-V curves were measured in 90 COPD patients (43 with chronic bronchitis, 47 with emphysema) and 31 complicated with cor pulmonale, all of them were in the ameliorated period. The indices selected were FVC, V75, V50, V25. Both the measured value and the measured value/predicted value (%) of all indices showed chronic bronchitis > emphysema > cor pulmonale. Never was there the concave type of normal humans in the F-V curves of COPD and cor pulmonale patients; however, the convex type was much increased in the curves and the hyperbolic type specific to COPD and cor pulmonale appeared. The mechanisms of formation for plateau, convex and hyperbolic types were analysed with the wave-speed theory. In summary, the unifying rule for the transformation of F-V curve configuration from normal adolescents to old persons, smokers, COPD and cor pulmonale patients in various degrees can be outlined as, concave type normality convex type abnormality hyperbolic type. This implicates a unifying process of pulmonary functions from healthy state to weakness and from slight to serious abnormality.

Adult↗

PubMed2000

[Spectroscopy performances of Yb3+ doped YAG crystal].

The absorption and emission properties of Yb:YAG with different Yb3+ doped concentration have been studied systematically. The emission cross section has been evaluated using the absorption cross section and principle of reciprocity, which was consistent with previous reports. The absorption spectra of Yb2+ and color center were observed in as-grown Yb:YAG boules, which are removed by annealing the boules in oxygen at 1,300 degrees C for 24 h. The photon excited and X-ray excited optical luminescence of Yb:YAG were first discussed. The results indicated that Yb:YAG crystal was favourable for high-power diode-pumping.

Chemical Phenomena↗

PubMed2000

[Spectrometric determination of nutritional elements in the medicine-food flowers].

A study was carried out on the contents of nutritional elements in some medicine-food flowers by atomic absorption spectrometry. The results showed that flowers contain much more contents Fe, Ca, Mg and Co. The range of the average recovery in this method is 94%-108%, which indicate that the method we used is practicable. And flower is a kind of typical food source of containing high content of K and low content of Na. It is worth much more comprehensive utilization.

Asteraceae↗

PubMed1999

The role of CCR7 in TH1 and TH2 cell localization and delivery of B cell help in vivo.

Subsets of murine CD4+ T cells localize to different areas of the spleen after adoptive transfer. Naïve and T helper 1 (TH1) cells, which express the chemokine receptor CCR7, are home to the periarteriolar lymphoid sheath, whereas activated TH2 cells, which lack CCR7, form rings at the periphery of the T cell zones near B cell follicles. Retroviral transduction of TH2 cells with CCR7 forces them to localize in a TH1-like pattern and inhibits their participation in B cell help in vivo but not in vitro. Thus, differential expression of chemokine receptors results in unique cellular migration patterns that are important for effective immune responses.

Adoptive Transfer↗

PubMed1999

Risk factors for meningioma in adults: a case-control study in northeast China.

A hospital case-control study of meningioma was conducted in Heilongjiang Province in northeast China between September 1989 and December 1996. It included 183 cases of newly diagnosed primary meningioma and 366 individually matched hospital controls with non-neoplastic and non-neurological disease selected from six major hospitals. Cases and controls were matched by sex, age and area of residence and interviewed in the hospital wards to obtain information on medical history, occupation and lifestyle. No association with liquor or beer consumption was apparent. Cigarette smoking was positively associated with meningioma risk in women but not in men. In women, compared with non-smokers, the adjusted OR for pack-years of smoking above the median (124) was 6.2 (CI 2.04-18.87). Both of these observations contrast with the results of a study of glioma in the same population, using similar methods. The risk of meningioma was positively associated with reported occupational exposure to lead, tin, cadmium and ionising radiation in both genders.

Adult↗

PubMed1999

Distinct immunological and biochemical properties of thyroid peroxidase purified from human thyroid glands and recombinant protein produced in insect cells.

The biosynthesis of thyroid hormone from thyroglobulin is catalysed by thyroid peroxidase (TPO), an integral membrane protein. TPO is also a major autoantigen in autoimmune thyroid disease and autoantibodies to TPO are markers for disease activity. Large quantities of purified TPO are essential for elucidating its structure and understanding its role in disease activity. We describe the high yield purification of full-length recombinant human TPO from baculovirus infected insect cells and compare it to purified native TPO from human thyroid glands. In contrast to native human TPO, the human TPO produced in insect cells as a recombinant protein was insoluble and resistant to solubilisation in detergents. Reversible substitution of lysine residues with citraconic anhydride led to increased solubility of the recombinant TPO, allowing high-yield purification by monoclonal antibody chromatography. The purified enzyme preparation was shown to be TPO by its reactivity with monoclonal and polyclonal antibodies by enzyme linked immunosorbent assay and Western blotting. Both the human and recombinant purified TPO preparations also react with sera from patients with autoimmune thyroid disease, although the binding of conformational dependent autoantibodies was considerably lower to the recombinant TPO than to the native TPO. This suggests that the recombinant TPO may differ in some aspects of its tertiary structure. The purified recombinant TPO was devoid of enzyme activity, in contrast to the enzymatically active, purified human TPO preparations. Both preparations contained comparable amounts of haem (R(z)=0.269), but a shift in the Soret band of recombinant TPO (402 nm) from that of natural TPO (409 nm) indicates that the lack of enzymatic activity of the recombinant enzyme may be due to changes in the protein backbone surrounding the haem. Both the purified native and recombinant TPO, under non-denaturing conditions, show evidence of high molecular mass oligomers, although the latter preparation is prone to a greater degree of aggregation. In conclusion, our studies indicate that recombinant TPO generated in insect cells is conformationally distinct from the native TPO, is insoluble and enzymatically inactive, consistent with the difficulties associated with its purification and crystallisation.

Animals↗

PubMed1999

Block of granulocytic differentiation of 32Dcl3 cells by AML1/ETO(MTG8) but not by highly expressed Bcl-2.

The chimeric gene, AML1/ETO (MTG8), generated in t(8;21) acute myeloid leukemia enhances the expression of Bcl-2. To evaluate whether this enhancement is the primary role of AML1/ETO in leukemogenesis, effects of over-expression of Bcl-2 in the murine myeloid precursor cell line, 32Dcl3, were examined. When 32Dcl3 cells expressing exogenous Bcl-2 were induced to differentiate, the onset of morphological differentiation was delayed. However, even the cells expressing very high levels of exogenous Bcl-2 eventually underwent differentiation without a significant decrease in the synthesis of Bcl-2. On the contrary, 32Dcl3 cells stably expressing AML1/ETO were completely resistant to differentiation and continued to grow in the presence of G-CSF. These results are consistent with the interpretation that stimulation of Bcl-2 expression is not the primary target of AML1/ETO.

Animals↗

PubMed1999

Overexpression of ErbB2 impairs ligand-dependent downregulation of epidermal growth factor receptors via a post-transcriptional mechanism.

The mechanism by which ErbB2 exerts its oncogenic effect is poorly defined. In this article we show that ErbB2 co-expression slows ligand-dependent growth factor receptor downregulation in NIH 3T3 transfectants. Ligand dependence of cell growth and MAP kinase signaling are retained in epidermal growth factor receptor (EGFR) transfectants but are abolished in ErbB2-expressing cells, which grow and signal constitutively. In association with this phenomenon, we have noticed that ErbB2-expressing cells contain increased amounts of EGFR, which is hyperphosphorylated. EGFR overexpressors do not contain increased levels of ErbB2, however, tending to exclude a transfection artifact caused by saturation of receptor processing. EGF treatment of EGFR transfectants results in more rapid EGFR downregulation than occurs in ErbB2 transfectants, but Northern blot analysis demonstrates reduced basal EGFR gene expression in ErbB2 transfectants. We conclude that ErbB2 expression impairs EGFR downregulation via a posttranscriptional mechanism and propose that ErbB2 overexpression may sensitize tumor cells to the mitogenic effects of heterologous growth factors by retarding degradation of liganded heterodimers.

3T3 Cells↗

PubMed1999

[Effect of methyl tertiary butyl ether on the expression of proto-oncogenes and function genes].

Methyl tertiary butyl ether (MTBE) is a new gasoline additive, which is used to increase the combustion of gasoline and to reduce the emission of harmful exhaust from automobile. The mechanism for the carcinogenesis of MTBE in animals is not clear. Immunohistochemistry method was used to detect the effect of MTBE on the expression of c-myc and p21 proteins in NIH3T3 cells. Dot hybridization method was used to explore the expression of c-myc gene and GST-P(glutathione S-transferase-P) gene in the of MTBE treated rats. The results showed that MTBE could enhance the expression of c-myc protein, but had no effect on p21 protein. MTBE could induce high expression of c-myc gene, and had no effect on the expression of GST-P gene. These results suggest that the high expression of c-myc gene induced by MTBE might be one of the mechanisms of its carcinogenicity in animal.

3T3 Cells↗

PubMed1999

Diet and brain cancer in adults: a case-control study in northeast China.

A hospital-based case-control study was conducted in the Heilongjiang Province of northeast China between May 1993 and May 1995. A total of 129 histologically confirmed brain cancer cases (73 gliomas and 56 meningiomas) and 258 matched controls were interviewed in 6 major hospitals to examine the influence of dietary factors in developing brain cancer. Information was obtained about frequency of consumption of 57 food items. Odds ratios (ORs) were obtained from conditional logistic regression, including allowance for socio-demographic factors, alcohol, tobacco and total energy intake. Consumption of fresh vegetables (OR = 0.29 for the highest quartile compared with the lowest one), and specifically of Chinese cabbage and onion, fruit (OR = 0.15), fresh fish (OR = 0.38) and poultry (OR = 0.16) was inversely related to the risk of developing brain cancer. A protective effect was also seen for vitamin E intake, calcium and, although non-significantly, beta-carotene and vitamin C. Risk of brain cancer increased with consumption of salted vegetables (OR = 2.54) and salted fish.

Adult↗

PubMed1999

Transforming growth factor-alpha short-circuits downregulation of the epidermal growth factor receptor.

Transforming growth factor-alpha (TGFalpha) is an epidermal growth factor receptor (EGFR) ligand which is distinguished from EGF by its acid-labile structure and potent transforming function. We recently reported that TGFalpha induces less efficient EGFR heterodimerization and downregulation than does EGF (Gulliford et al., 1997, Oncogene, 15:2219-2223). Here we use isoform-specific EGFR and ErbB2 antibodies to show that the duration of EGFR signalling induced by a single TGFalpha exposure is less than that induced by equimolar EGF. The protein trafficking inhibitor brefeldin A (BFA) reduces the duration of EGF signalling to an extent similar to that seen with TGFalpha alone; the effects of TGFalpha and BFA on EGFR degradation are opposite, however, with TGFalpha sparing EGFR from downregulation but BFA accelerating EGF-dependent receptor loss. This suggests that BFA blocks EGFR recycling and thus shortens EGF-dependent receptor signalling, whereas TGFalpha shortens receptor signalling and thus blocks EGFR downregulation. Consistent with this, repeated application of TGFalpha is accompanied by prolonged EGFR expression and signalling, whereas similar application of EGF causes receptor downregulation and signal termination. These findings indicate that constitutive secretion of pH-labile TGFalpha may perpetuate EGFR signalling by permitting early oligomer dissociation and dephosphorylation within acidic endosomes, thereby extinguishing a phosphotyrosine-based downregulation signal and creating an irreversible autocrine growth loop.

3T3 Cells↗

PubMed1999

[A prevalence study on injuries among 2,553 children 7-16 years old].

OBJECTIVE: In order to find out the present situation and cause of injuries among children. METHODS: A cluster sampling study on the conditions of injuries was conducted among 2,553 children 7-16 years old during the period of October 1996 to September 1997 in Shantou City, Guangdong Province. RESULTS: There was a trend that the incidence of injuries increased with age among children. The overall incidence of injuries was 37.96% with schoolboys higher than schoolgirls (P < 0.05). There were 38.1% children who had more than two episodes. Falls took the leading type of incidence among both sexes and all age groups. Among the causes of injuries, playing, motion, riding and walking ranked the consecutive leading 4 places. The places where injuries occurred were mainly at home and then on campus. Self injured was mostly seen followed with hurt by others (classmate, sibling, et al). Medium and serious injuries took up 8% with a disability rate of 121.4/100,000. CONCLUSION: Some preventive measures were preliminarily suggested.

Adolescent↗