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Biomedical subjects

M S Zhang

Publications and source records attributed to M S Zhang.

At least 19 recordsLinked to original sources
PubMed2001

Model calculating annual mean atmospheric dispersion factor for coastal site of nuclear power plant.

This paper describes an atmospheric dispersion field experiment performed on the coastal site of nuclear power plant in the east part of China during 1995 to 1996. The three-dimension joint frequency are obtained by hourly observation of wind and temperature on a 100 m high tower; the frequency of the "event day of land and sea breezes" are given by observation of surface wind and land and sea breezes; the diffusion parameters are got from measurements of turbulent and wind tunnel simulation test. A new model calculating the annual mean atmospheric dispersion factor for coastal site of nuclear power plant is developed and established. This model considers not only the effect from mixing release and mixed layer but also the effect from the internal boundary layer and variation of diffusion parameters due to the distance from coast. The comparison between results obtained by the new model and current model shows that the ratio of annual mean atmospheric dispersion factor gained by the new model and the current one is about 2.0.

Air Pollutants, Occupational↗
PubMed2001

[Determination of solanesol in the extracts of tobacco leaves by high performance liquid chromatography].

A method for the determination of solanesol in the extracts of tobacco leaves by high performance liquid chromatography has been developed. The column used was Shim-pack CLC-SIL(5 microns, 5 mm i.d. x 150 mm) and the UV detector was set at 215 nm. The eluent was a mixture of n-hexane and isopropyl alcohol (98:2, V/V). As the results showed, the linear range was 1 microgram-10 micrograms(r = 0.9997), the average recovery of solanesol was 98.1% and the relative standard deviation was 1.9%. This method is fast, accurate and reproducible.

Chromatography, High Pressure Liquid↗
PubMed2000

[Determination of phenols in environmental water with bromination derivatization and gas chromatography].

A method for the determination of phenols in environmental water with bromination derivatization and gas chromatography is described. The phenols were transformed to bromophenols and then extracted with toluene and separated by the FFAP wide-bore capillary column and detected by electron capture detector (ECD). The results showed that the linear ranges were 0.06-80 micrograms/L for o-methylphenol and p-methylphenol, 0.03-40 micrograms/L for phenol and m-methylphenol. The detection limits for o-methylphenol, p-methylphenol, phenol and m-methylphenol were 0.03, 0.06, 0.01, 0.015 microgram/L respectively. The method is simple, rapid and reliable for determining phenols in environmental water.

Chromatography, Gas↗
PubMed2000

[The determination of cantharidin in AIDI liquid injection by gas chromatography].

A method for the determination of cantharidin in AIDI liquid injection with gas chromatography is described. The cantharidin was extracted with dichloromethane and then determined by gas chromatography with OV-17 packed column and FID detector. Its distribution constant between dichloromethane and water was 480. The extraction recoveries of cantharidin were 99%-102%. The calibration curve was Y = -113 + 35,900X, r = 0.9999 and the detection limit was 0.02 mg/L in liquid injection. As the results showed, the method is simple, rapid, sensitive and precise for determining cantharidin in AIDI liquid injection.

Antineoplastic Agents↗
PubMed1997

[Epidemiological trend and its impact on malaria control programme in Shenzhen from 1950-1995].

Shenzhen has been developed as the first economic special zone in China. Two large scale outbreaks of vivax malaria have occurred in the history. Anopheles anthropophagus has been identified as the major vector. For the last 45 years, we have adopted an effective measure for malaria control based on the epidemiological characteristics in different period. As a result, the morbidity rate of malaria has been under control given the condition of social and economy development and the big increase of mobile population.

Animals↗
PubMed1995

A field study of tritium migration in groundwater.

A field study of tritium migration from an underground nuclear explosion was carried out for more than 7 years. A series of satellite wells was drilled around the explosion cavity, which is within a nuclear test site water-supply aquifer. Samples from various wells were analysed. In this way, variations in the tritium concentration of water from different wells were determined, and the extent of tritium migration during the 7 years after the detonation was examined. The maximum tritium concentration reached in water from various wells is just 52-times higher than the maximum permissible concentration for drinking water and decreased afterwards. According to the results obtained, the flow rate of groundwater was inferred to be about 91 m per year and the maximum contamination distance of water supplies by the tritium were < or = 2 km from the explosion cavity.

China↗
PubMed1994

[Effects of methylflavonolamine hydrochloride on tension and cAMP of isolated guinea pig trachea].

Effects of methylflavonolamine (4'-methyl-7-(2-hydroxy-3-isopropylaminopropoxy)-flavone hydrochloride, MFA) on the tension and cAMP content of isolated guinea pig tracheal smooth muscle strips were studied. MFA (0.03-0.6 mmol.L-1) dose-dependently reduced KCl, acetylcholine (ACh) and histamine (Hist)-induced contractions with intracellular increase in cyclic AMP. The reduction in contraction and increase in cAMP were well correlated positively. MFA (0.03 mmol.L-1) showed synergism with isoprenaline (Iso) and aminophylline (Ami) in bronchodilation. The synergism with Iso but not Ami was accompanied by an increase in cAMP levels. It is suggested that the MFA-induced bronchodilation is related to the increase in intracellular cAMP level. The calcium antagonistic effect may be involved in MFA-induced bronchodilation.

Aminophylline↗
PubMed1993

Methylflavonolamine protects aorta from atherosclerosis in cholesterol-fed rabbits.

The effect of methylflavonolamine [4'-methyl-7-(2-hydroxy-3-isopropylamino-propoxy)-flavone hydrochloride, MFA], synthesized recently by the Shanghai Institute of Pharmaceutical Industry, on the development of atherosclerosis was studied in male New Zealand white rabbits fed cholesterol for 10 wk. MFA, 7 mg.kg-1 daily ip, did not significantly alter the serum total cholesterol, HDL, and triglyceride levels, but significantly lowered the aortic cholesterol and calcium contents. Atheromatous lesions covered 53.3 +/- 11.8% of the intimal surface of the aorta in the saline group and 11.3 +/- 2.3% in the MFA group (P < 0.01). We conclude that MFA suppresses cholesterol-induced atherosclerosis.

Animals↗
PubMed1992

Transplantation of cultured premyelinating oligodendrocytes into normal and myelin-deficient rat brain.

Cultures of oligodendroglial cells at various stages of maturation, from progenitors to maturing oligodendrocytes, were prepared from neonatal rat brain primary cultures and then were prelabeled in the culture dish with the fluorescent dye, fast blue (FB). Single cell suspensions were grafted into normal or myelin-deficient rat brains. The normal as well as the myelin-deficient in vivo environment allowed cell survival, migration, and differentiation. The FB+ cells expressed the oligodendroglial markers, glycerol phosphate dehydrogenase, galactocerebroside, and myelin basic protein. In the normal rat transplanted cells were identifiable at all times studied up to 24 weeks. Extensive migration of FB+ cells was observed in whole-brain sagittal sections. Our results show that the plasticity of oligodendroglia differentiation, extensively studied in vitro, can now be investigated in the normal and myelin-deficient in vivo environment.

Animals↗
PubMed1992

[Effects of methylflavonolamine hydrochloride on contractility of isolated rabbit ileum].

Methylflavonolamine hydrochloride (MFA), verapamil (Ver), and trifluoperazine (Tri) inhibited the contractions induced by submaximal concentrations of acetylcholine (ACh) and serotonin (5-HT). IC50 values (mumol.L-1) were 33.2 +/- 0.7, 0.276 +/- 0.018, 3.83 +/- 0.23, and 15.31 +/- 0.10, 0.233 +/- 0.017, 2.33 +/- 0.20, respectively. MFA, Ver, and Tri inhibited the contractions induced by CaCl2 and pD'2 values were 4.3 +/- 0.3, 6.23 +/- 0.22, 4.99 +/- 0.24, respectively. MFA 3 mumol.L-1, Ver 0.03 mumol.L-1, and Tri 3 mumol.L-1 inhibited the contractions induced by ACh in Ca(2+)-free medium, while MFA 60 mumol.L-1, Tri 30 mumol.L-1, but not Ver 0.6 mumol.L-1, had pronounced inhibitions on extracellular calcium-dependent contractions induced by ACh. These results suggest that MFA has a calcium antagonistic effect and that MFA is similar to Tri, but not Ver, in mechanism.

Animals↗
PubMed1991

Disruption of the Golgi apparatus by brefeldin A inhibits the cytotoxicity of ricin, modeccin, and Pseudomonas toxin.

We have studied the cytotoxicity of ricin in cells treated with brefeldin A (BFA), which dramatically disrupts the structure of the Golgi apparatus causing Golgi content and membrane to redistribute to the ER. BFA inhibits the cytotoxicity of ricin in Chinese hamster ovary, normal rat kidney, and Vero cells and abolishes the enhancement of ricin cytotoxicity by NH4Cl, nigericin, swainsonine, and tunicamycin or by a mutation in endosomal acidification. BFA protects cells from the cytotoxicities of modeccin and Pseudomonas toxin, but has no effect on the intoxication by diphtheria toxin. Pretreatment of BFA does not protect cells from ricin treatment in the absence of BFA. Our results suggest that ricin, modeccin, and Pseudomonas toxin share a common pathway of intracellular transport from endosomes to the Golgi region where they are released into the cytosol. In contrast, the lack of protection of Vero cells from diphtheria toxin by BFA indicates that diphtheria toxin is released from acidified endosomes without involving the Golgi region.

ADP Ribose Transferases↗
PubMed1990

Developmental regulation of myelin-associated genes in the normal and the myelin deficient mutant rat.

Oligodendrocyte development and myelinogenesis, both in vivo and in vitro, are characterized by the sequential and coordinate expression of markers which participate in the differentiation of oligodendrocytes as a prerequisite for myelination. The myelin deficient (md) rat shows greatly reduced mRNA expression for several oligodendrocyte markers: glycerol phosphate dehydrogenase (GPDH), myelin basic protein (MBP) and proteolipid protein (PLP). Brain GPDH mRNA levels are initially equivalent in md and unaffected littermates, but the mutant rats fail to display the normal developmental increase in gene expression. Immunostaining of brain tissue sections also reveals decreased expression of these oligodendrocyte markers. The number of oligodendrocytes containing GPDH-like immunoreactivity is reduced in mutant rats, and in general these cells appear morphologically less complex with shorter processes. However, the intensity of staining in many oligodendrocytes appears equivalent to that observed in unaffected rats. Expression of the neuronal marker, glutamic acid decarboxylase, and the astrocyte markers, glutamine synthetase and glial fibrillary acidic protein, are largely unaffected at either the mRNA or protein level. Mixed glial cultures prepared from the brains of neonatal male md rats possess fewer oligodendrocytes compared to cultures derived from unaffected littermates, and the temporal sequence of marker development is delayed. Although an abnormality in the PLP gene is suspected in the md rat, these findings document profound deficits in many oligodendrocyte gene products.

Animals↗
PubMed1990

Increased cytotoxicity of ricin in a putative Golgi-defective mutant of Chinese hamster ovary cell.

We have studied the cytotoxicity of ricin in a monensin-resistant mutant (MonR-31) of Chinese hamster ovary (CHO) cell line which is presumably altered in Golgi functions/structures. The cytotoxicity of ricin was increased in MonR-31 mutant cells compared with that in its parental CHO cells. In wild-type CHO cells, the cytotoxicity of ricin was enhanced by HN4Cl, bafilomycin A1, or nigericin. The enhancement of ricin cytotoxicity by these compounds was greatly reduced in MonR-31 mutant cells. Brefeldin A (BFA), which disrupts the structure of the Golgi apparatus, inhibits the cytotoxicity of ricin in both CHO and MonR-31 cells. We have also examined the effects of glycosylation inhibitors and the removal of high mannose oligosaccharide chains in ricin on the ricin hypersensitivity in MonR-31 cells. The hypersensitivity of MonR-31 cells to ricin is apparently not due to any difference in glycosylation between CHO and MonR-31 cells or in the processing of oligosaccharides on ricin by the target cells. Nigericin at low concentration (10 nM), which has no effect on the cytotoxicity of diphtheria toxin, enhances the ricin cytotoxicity, but inhibits the modeccin cytotoxicity. Our results suggest that important step(s) in the intoxication process of CHO cells by ricin and modeccin take place in the Golgi region.

Alkaloids↗
PubMed1989

[Cost-effectiveness analysis of two-dimensional/Doppler echocardiography, cardiac catheterization and angiography in the diagnosis of congenital heart disease].

To compare the costs and effectivenesses of 2-dimensional/Doppler echocardiography (2D/DE), cardiac catheterization (CC) and angiography (CA) in the evaluation of cardiac anatomy in patients with congenital heart disease, these three kinds of examinations were performed in 100 patients before operation. The 100 patients had 120 separate cardiovascular abnormalities, of which 100 (83.3%) were prospectively identified by 2D/DE. The sensitivity and specificity of 2D/DE were: ASD, 87.9% and 100%; VSD, 97.9% and 96.1%; PDA, 86.7% and 98.2%, Tetralogy of Fallot, 6 of 6 patients; the overall sensitivity and specificity of the less common defects, 31.6% and 95.8%. Ninety-seven (80.8%) were prospectively identified by catheterization. The sensitivity and specificity of catheterization were: ASD, 87.9% and 100.0%; VSD, 80.9% and 94.6%; PDA 93.3% and 96.6%; Tetralogy of Fallot, 6 of 6 patients, the less common defects, 52.6% and 95.5%. Forty-five (81.8%) were prospectively identified by angiography in 55 patients. The sensitivity and specificity of angiography: ASD, 5 of 7 patients, VSD, 88.0% and 94.3%; PDA, 2 of 2 patients; Tetralogy of Fallot, 5 of 5 patients; the less common defects, 68.8% and 100.0%. The economic evaluations were performed. The costs of the depreciation (including equipments and houses), hospital bed, water and electricity, management and staffs' wage were: 2D/DE, RMB 46.09 per patient; catheterization, RMB 314.17 per patient; angiography, RMB 314.17. The ratios of cost to outcome (cost per correct diagnosis) of 2D/DE, CC and CA were: 55.33, 388.82 and 384.07 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Short-term multidrug therapy in multibacillary leprosy--review of 80 cases in two provinces of China (1983-1988).

Thirty-three active multibacillary patients from nine counties of Weifang Prefecture, Shandong Province, and 47 active cases from Menla County, Yunnan Province, People's Republic of China, were treated with 24 and 27 months of multidrug therapy (MDT), respectively, in 1983. Clinical assessments, smears, and histopathologic examinations were carried out independently by study teams from the Institutes of Dermatology of these two provinces. Reexaminations at 12-14 months and at termination of therapy showed marked improvement, and there was continued improvement at 12-18 and 33 months on follow up. Conversion of the bacterial index to negativity was 0/33, 5/47 for the patients from Shandong and Yunnan provinces, respectively, at the end of MDT and 2/33 at 12 months' and 17/47 at 18 months' follow up, which increased to 21/33 and 26/44 at 33 months' follow up. Regression of specific infiltration was about 21%-100% after 24-27 months of MDT; further regression to 95%-100% occurred at 33 months' follow up.

Adult↗
PubMed1988

Methylflavonolamine hydrochloride inhibits contractions induced by noradrenaline, calcium and potassium in rabbit isolated aortic strips.

1. The effects of methylflavonolamine hydrochloride (4'-methyl-7-(2-hydroxy-3-isopropylamino-propoxy)-flavone hydrochloride, MFA) were investigated and compared with verapamil and papaverine on rabbit isolated aortic strips, which were contracted by noradrenaline, calcium and potassium. 2. Pre-incubation for 25 min with either MFA (0.03 to 0.2 mM) or papaverine (0.03 to 0.2 mM) induced non-parallel and concentration-dependent rightward displacements of the curves to noradrenaline (0.00001 to 0.1 mM) with the maximal response depressed. The calculated pD2' values (mean +/- s.d.) were 3.89 +/- 0.15 for MFA and 3.93 +/- 0.05 for papaverine, respectively. Verapamil (0.03 to 0.2 mM) inhibited the contraction induced by noradrenaline in a competitive manner with a pA2 value of 5.91 +/- 0.83. 3. In depolarized aortic strips of the rabbit, prior exposure to MFA (0.03 to 0.3 mM) and papaverine (0.03 to 0.2 mM) shifted the cumulative curves to Ca2+ (0.003 to 100 mM) parallel to the right with the maximal responses depressed, pD'2 values being 3.88 +/- 0.05 and 3.89 +/- 0.13, respectively. Verapamil produced comparable inhibition of the contraction at much lower concentrations (30 to 300 nM). 4. MFA (0.03 and 0.1 mM) inhibited the contraction elicited by graded depolarization at a constant Ca2+ concentration with a pD'2 value of 4.09 +/- 0.07. 5. The present results show that MFA has some actions consistent with a calcium antagonist. It resembles papaverine more closely than verapamil.

Animals↗