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Biomedical subjects

G T Wu

Publications and source records attributed to G T Wu.

8 recordsLinked to original sources
PubMed1997

[Experimental study on antagonism of ginkgolides against effect of platelet-activating factor on lung strip of guinea pigs].

OBJECTIVE: To investigate the action of ginkgolides antagonizing the contraction of guinea pigs' lung strip induced by the mixture of platelet-activating factor (PAF) and platelets and its effect of preventing the PAF caused damage of beta-adrenergic receptors. METHODS: The contraction of guinea pigs' isolated lung strip was measured. RESULTS: The mixture of PAF and platelet could produce a serious contraction of lung strip, the IC50 reached 4.69 x 10(-7) mol/L, while the contraction induced by PAF alone was relatively mild, its IC50 only 6.66 x 10(-4) mol/L, the difference between them was significant (P < 0.05). When the platelets were preincubated with ginkgolides for 10 minutes in Tris-Tyrode's buffered saline, the effects of PAF and platelets mixture were significantly inhibited (P < 0.05). Exposure of guinea pigs' lung strip to PAF in vitro resulted in a loss of beta-adrenergic receptors and weakened its respones to isoproterenol, a receptor activating factor, the EC50 would be increased from 1.38 x 10(-6) mol/L to 6.25 x 10(-6) mol/L, P < 0.05. This effect of PAF could also be inhibited by ginkgolides (P < 0.05). CONCLUSION: Ginkgolides is a promising PAF antagonist, and might be used in treating bronchial asthma.

Animals↗
PubMed1996

[Effect of hemin in treating hemorrhagic anemia and toxicity].

AIM: To study the effect of hemin in treating hemorrhagic anemia and toxicity. METHODS: Fifty rats with hemorrhagic anemia were randomly divided into 5 groups with different dosage of hemin (93, 168, 300 mg.kg-1.d-1), ferrous gluconate (FG 300 mg.kg-1.d-1), and water, ig for 7 d. Twenty mice fed with hemin (6.0 g.kg-1.d-1) in 24 h for observing acute toxicity effects. Long-term toxicity were observed in 80 rats given hemin (0.65, 1.3, 2.6 g.kg-1.d-1) in 3 months. RESULTS: Hb of the rats of corresponding groups were 66-->121, 71-->141, 66-->148, 69-->140, and 67-->112 g.L-1. There were no adverse effects observed on acute toxicity test. No abnormalitis were found in hemogram, liver renal function test, and autopsy. CONCLUSION: Hemin had a better effect than FG and no adverse effect was found in hemin.

Anemia, Iron-Deficiency↗
PubMed1995

Inhibitory effects of 2-[(diethylamino)acetyl]-1,2,3,4-tetrahydro-6, 7-dimethoxyl-1-[1'-(6"-methoxy-2"-naphthalenyl)ethyl]-isoquinoline on isolated guinea pig papillary muscle and heart atrium.

AIM: To investigate the cardiac actions of 2-[(diethylamino)acetyl]-1,2,3,4-tetrahydro-6, 7-dimethoxyl-1-[1'-(6"-methoxy-2"-naphthalenyl) ethyl]-isoquinoline (CPU57) by comparison with nifedipine and focus on its mechanism of actions. METHOD: The following were measured and recorded: 1) the rate and contraction of spontaneous beating of the guinea pigs right heart atrium, 2) the isometric tension of the electrically stimulated left heart atrium and the right papillary muscles. RESULTS: CPU57 had negative inotropic and negative chronotropic actions in isolated heart of guinea pigs as the typical calcium antagonist, nifedipine. However, CPU57 0.01-100 mumol.L(-1) produced less cardiac inhibitory potency than nifedipine and had much stronger negative inotropic action than negative chronotropic action. The decrease in external CaCl2 concentration from 1.5 to 0.3 mmol.L(-1) or increase to 7.5 mmol.L(-1), potentiated or reduced respectively, the inhibitory action of CPU57 on the contraction in paced left heart atrium in normal CaCl2 solution. CPU57 1-10 mumol.L(-1) also inhibited contractile response to CaCl2 in paced left heart atrium with pD2' value of 4.77. CONCLUSION: CPU57 has calcium antagonism on the heart of guinea pigs.

Animals↗
PubMed1978

Alcohol dehydrogenases from a facultative methylotrophic bacterium.

Alcohol-oxidizing enzymes of the facultative methylotroph PAR were investigated after growth of the bacteria on methanol and ethanol. During methanol growth only a phenazine methosulfate-linked alcohol dehydrogenase was detected. This enzyme had broad specificity for primary alcohols and was also capable of oxidation of secondary alcohols. It had a molecular weight of 112,000, was composed of two subunits of equal molecular weight, and showed an absolute requirement for ammonium ion for activation. During ethanol growth this enzyme was absent and was replaced by a typical nicotinamide adenine dinucleotide-linked alcohol dehydrogenase of molecular weight 150,000. The latter enzyme also had broad specificity but could not oxidize methanol. This enzyme was not found during methanol growth. These data show that the organism has two distinctly separate mechanisms for oxidation of alcohols.

Alcohol Oxidoreductases↗
PubMed1976

Sample stability: a suggested definition and method of determination.

We propose defining the stability of any chemical constituent of stored samples in terms that are quantitatively related to the precision of the measurement by which it is determined. We suggest that a constituent may be considered stable, for a stated period and under exactly defined conditions, when the average change in its measured value is less than a chosen number, K, of standard deviations of the data obtained by the measuring method over the concentration range in question. Based on this definition a technique utilizing a graphical truncated normal sequential test is presented as the appropriate experimental and statistical design for measuring stability. The statistical basis for the proposal is presented.

Chemistry, Clinical↗
PubMed1975

Statistical evaluation of method-comparison data.

Comparison of two methods for determining a substance is a common procedure in clinical chemistry. Almost without exception, normal theory statistics are used with the tacit assumption that the data under test show gaussian distributions. Experience has led us to question this assumption for populations of differences between values obtained by two methods applied to common samples and for populations of paired values for each method as used in correlation analysis. Data are presented from our laboratory to illustrate these points, as well as an examination of data from relevant papers that appeared in this journal from 1968 through 1973. These examples indicate that incorrect interpretation of results because of insufficient attention to non-gaussian distribution is a real and present danger. We present a systematic approach to the statistical aspect of comparing methods that enables one to avoid this problem.

Blood Chemical Analysis↗