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Biomedical subjects

W Huang

Publications and source records attributed to W Huang.

At least 631 records · Page 35Linked to original sources
PubMed1990

[Nutritive physiology of Psoralea corylifolia L].

Our study has shown that P. corylifolia absorbs and accumulates N2 and K2O most speedily in the periods of branching, flowering and fruiting, while P2O5 in the period of full flowering and fruiting. P2O5 is accumulated mainly in the seed and K2O in the stem. The nutriment accumulation is positively correlated with that of dry substances. To produce 100 kg of P. corylifolia an absorption of 10.59 kg of N2, 3.68 kg of P2O5 and 10.21 kg of K2O is needed.

Fabaceae↗
PubMed1990

[The role and mechanism of berberine on coronary arteries].

Berberine increased coronary artery flow of anesthetized open-chest canines and isolated guinea pig hearts with ventricular fibrillation induced by electric stimulus. The rabbits were protected by berberine from ischemic ECG changes caused by posterior pituitary hormones. Spasm of isolated swine coronary arterial rings responded to ergometrine was able to be prevented and treated effectively by berberine. On isolated swine coronary arterial strips, berberine shifted norepinephrine cumulative dose-response curve rightward parallelly without decreasing the maximal response. The pA2 value was 6.7. Contraction treatment effects post-PBMV, the cardiac function tended to decline with time, the decrease of ejection fraction, stroke volume and cardiac output were 0.03 +/- 0.007, 5.44 +/- 1.04 ml and 0.44 +/- 0.08 L/min respectively. This might be due to the unsuccessful control of activity of rheumatism after PBMV and it is necessary to pay attention to in the future.

Adrenergic alpha-Antagonists↗
PubMed1990

Hepatitis delta virus superinfection in Guangzhou area.

Biopsy and autopsy specimens of liver tissues of two series of patients, one of adults and the other children suffering from hepatitis B virus (HBV) infection were used to evaluate hepatitis delta virus antigen (HDAg) by direct immunoperoxidase staining method. The results showed that four HDAg positive cases were found among 30 cases of HBV infected adult patients (13.3%), and 6 were found in 44 cases in the children series (13.6%). Therefore, we are convinced that hepatitis delta virus (HDV) superinfection does exist in Guangzhou area. The superinfection rates in adults and children are almost identical.

Adult↗
PubMed1990

[Biological characteristics of Psoralea corylifolia L].

A study has been made on the biological characteristics of Psoralea corylifolia under general cultivating conditions. To search for the laws of growth and development so as to facilitate further studies on the cultivating techniques for higher production of Psoralea corylifolia.

Fabaceae↗
PubMed1990

[Electron microscopic observations on Pseudomonas cocovenenans].

A strain of food-poisoning bacterium has been isolated by Jin Jiexiang (1963) in China from the fermented cornflour that has gone bad. These pathogenic microorganism has been identified and named Pseudomonas by Zhao Naixin in 1988, which is the same species as P. cocovenenans. The characteristics of them were conformed to these of the species P. cepacia of section 2 of the genus Pseudomonas. In view of the fact that the fine structures of the above mentioned three strains of Pseudomonas have not been described yet, we decided to observe them with electron microscope. Results indicate there are many things in common among the three strains, such as: appearing short rods, 0.6-0.8 microns in diameter by 1.5-2.0 microns in length, one polar multiflagella; non-pili, non-capsules, non-endospores; containing intranuclear inclusions (electron-dense bodies or concentric laminae bodies), accumulating intracytoplasmic PHB granules; forming filaments, minicells and bizarrecells; producing extracellular cellulose-like materials by the three strains have not been reported previously.

Microscopy, Electron↗
PubMed1989

On the role of long incubation periods in the dynamics of acquired immunodeficiency syndrome (AIDS). Part 1: Single population models.

In this study, we investigate systematically the role played by the reproductive number (the number of secondary infections generated by an infectious individual in a population of susceptibles) on single group populations models of the spread of HIV/AIDS. Our results for a single group model show that if R less than or equal to 1, the disease will die out, and strongly suggest that if R greater than 1 the disease will persist regardless of initial conditions. Our extensive (but incomplete) mathematical analysis and the numerical simulations of various research groups support the conclusion that the reproductive number R is a global bifurcation parameter. The bifurcation that takes place as R is varied is a transcritical bifurcation; in other words, when R crosses 1 there is a global transfer of stability from the infection-free state to the endemic equilibrium, and vice versa. These results do not depend on the distribution of times spent in the infectious categories (the survivorship functions). Furthermore, by keeping all the key statistics fixed, we can compare two extremes: exponential survivorship versus piecewise constant survivorship (individuals remain infectious for a fixed length of time). By choosing some realistic parameters we can see (at least in these cases) that the reproductive numbers corresponding to these two extreme cases do not differ significantly whenever the two distributions have the same mean. At any rate a formula is provided that allows us to estimate the role played by the survivorship function (and hence the incubation period) in the global dynamics of HIV. These results support the conclusion that single population models of this type are robust and hence are good building blocks for the construction of multiple group models. Our understanding of the dynamics of HIV in the context of mathematical models for multiple groups is critical to our understanding of the dynamics of HIV in a highly heterogeneous population.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Stimulus interaction between CO2 and almitrine in the cat carotid chemoreceptors.

The hypothesis that augmentation of the carotid chemoreceptor response to hypoxia by almitrine is due in part to an increased response to CO2 was tested by using single or few fiber preparation of carotid body chemosensory fibers in 12 cats anesthetized with alpha-chloralose. To differentiate between the plausible mechanisms of effects, we also tested the responsiveness of the afferents to cyanide and nicotine before and after almitrine. After a saturation dose of almitrine (1 mg.kg-1 followed by 0.5 mg.kg-1.h-1) the chemosensory responses to CO2 strikingly increased even during hyperoxia: the afferents showing an increased transient peak activity at the onset of hypercapnia, an augmented steady-state response to CO2 stimulus, and a decreased arterial PCO2 stimulus threshold. Thus, the effect of almitrine on carotid chemoreceptor response to hypoxia could be explained, at least in part, by its multiplicative stimulus interaction with CO2. After almitrine, the chemoreceptor response to cyanide, which is dependent on arterial PO2, was not particularly augmented relative to those of nicotine. Accordingly, the O2-sensing mechanism does not appear to be the primary site of almitrine effect. The results also indicate that the site of CO2 chemoreception resides downstream from those of hypoxia.

Almitrine↗
PubMed1989

[Determination of flecainide concentration in blood plasma by HPLC and pharmacokinetic parameters in volunteers].

A high performance liquid chromatographic method (ultraviolet detection) for the determination of flecainide concentration in human plasma was reported. Flurazepam (dalmadorm) was used as the internal standard. A mixture of methanol and deionized water containing ion paired reagent served as the mobile phase. The regression equation of flecainide was: y = 0.0017x + 0.0131, r = 0.9975. The extraction recoveries exceeded 94%, and the coefficients of variation (both within the same day and in different days) were less than 5%. The pharmacokinetic parameters in Chinese volunteers after taking flecainide were: Ka = 0.908h-1, T1/2 = 8.131h, peats time = 3.487h, AUC = 441.8ng.h/ml. The mean plasma concentration of flecainide in cases responded well to this drug was 423.6 +/- 227.4ng/ml.

Adult↗
PubMed1989

[Electrocochleography and the glycerol test in the diagnosis of Meniére's disease].

ECochG and glycerol test are two kinds of objective examinations for the diagnosis of Ménière's disease. Previous reports showed that the positive rates in both methods vary widely. In the present study, the incidence of abnormal SP enhancement was 63% (51 out of 81 ears in 70 patients). The SP enhancement correlated with the symptoms, especially aural fullness and high frequency hearing loss. The glycerol test was preformed in 25 patients (29 ears). The positive rate was 55.2%. There was a high positive rate of glycerol test in patients with low frequency and fluctuant hearing loss. Both examinations had a complementary effect in the diagnosis of Ménière's disease.

Adolescent↗
PubMed1988

Relationship between sympathetic and phrenic nerve responses to peripheral chemoreflex in the cat.

To test the hypothesis that peripheral chemoreflex effect on the preganglionic cervical sympathetic nerve (PSN) activity is entirely mediated by the central respiratory drive (CRD), as expressed in the phrenic nerve (PN) activity, we studied the relationship between PN and PSN activities under controlled conditions of carotid chemosensory excitation in the anesthetized cats. The cats were vagotomized, paralyzed and artificially ventilated. Tracheal pO2 and pCO2, systemic blood pressure, activities of single or a few PSN and PN fibers and a PN bundle were simultaneously recorded. The PSN preparations, which were responsive to hypoxia and showed PN rhythm, were selected for the study. Carotid chemoreceptor excitation, produced by hypoxia (end-tidal pO2 approximately equal to 50 Torr) or by sodium cyanide injection (50-100 micrograms, i.v.), elicited 3 types of responses: (1) the PSN discharged during the silent period of PN activity, although the PSN peak activity was still coupled to the PN peak activity, (2) PSN discharged only during PN activity, and (3) during the absence of PN discharge induced by hyperventilation hypocapnia, cyanide injection stimulated the PSN without PN activity. These observations suggest a model of chemoreflex control of sympathetic nerve activity which consists of two parts: one is dependent on PN activity and the other is not. Accordingly, all PSN chemoreflex responses may not be integrated with all inspiratory chemoreflexes.

Animals↗
PubMed1988

Multiple forms of growth inhibitors secreted from cultured rat liver cells: purification and characterization.

It was found that a non-tumorigenic epithelial cell line from the liver of a Buffalo-strain rat (BRL) secreted into the culture medium various inhibitors of the growth of BRL and RSV-BRL (tumorigenic BRL transformed by infection of Rous sarcoma virus). The secreted inhibitors were classified into two types: one inhibited the growth of BRL to a greater extent than that of RSV-BRL (non-tumorigenic BRL growth inhibitor, NGI), and the other, vice versa (tumorigenic BRL growth inhibitor, TGI). Two NGI (NGI-I and NGI-II) and two TGI (TGI-I and TGI-II) were highly purified from the serum-free conditioned medium. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis without 2-mercaptoethanol, NGI-I and II gave protein bands with molecular weights (Mr) of 56,000 and 21,000, respectively. TGI-I and II gave a band that migrated faster than bromophenol blue marker dye, but they did not pass through an ultrafiltration membrane with an Mr cutoff of 5,000. In the presence of a reducing reagent, only NGI-II showed a decrease of Mr, from 21,000 to 11,000. NGI and TGI showed 50% growth inhibition with BRL and RSV-BRL, respectively, at 5-15 ng/ml in the medium containing 10% fetal calf serum. NGI and TGI all were stable to 1 M acetic acid (pH 2.3) and 6 M urea, but labile to 5 mM dithiothreitol or trypsin. Of the eight cell lines tested, NGI-I was most effective on BRL, NGI-II on BRL and HSC-3 (human tongue squamous carcinoma), and both TGI-I and II on RSV-BRL.

Animals↗
PubMed1987

Growth inhibitors in serum, platelets, and normal and malignant tissues.

The non-malignant epithelial cell line from Buffalo rat liver (BRL) and its malignant transformant obtained by Rous sarcoma virus infection (RSV-BRL) were used as the indicators. A survey was made in animals for growth inhibitors which could inhibit the growth of BRL, but not the growth of RSV-BRL in culture, under the consideration that the loss of the sensitivity to such inhibitors might be the most dominant cause for acquisition of tumorigenicity. From human platelets, a growth inhibitor was extracted with acid-ethanol and prepared to a homogeneous purity, separated from the major TGF-beta activity, which stimulated the anchorage-independent growth of NRK cells in the presence of EGF. The purified inhibitor (Mr 25-27k; pI 8.7-9.1) showed 50% inhibition on the growth of BRL at 20 pg/ml (0.7 pM), but hardly influenced the growth of RSV-BRL. Its inhibition was specific to epithelial cell lines, thus called epithelial growth inhibitor (EGI). It consisted of two subunits with practically identical Mr, which were cross-linked with disulfide bonds. Its sequence of N-terminal 10 amino acids was consistent with that of TGF-beta. In rats, serum contained a growth inhibitor with Mm 220k. The inhibitor, when treated with high concentrations of urea or guanidine-HCl, liberated an active component with Mr 30k and pI 5.2. When the growth inhibitor with Mm 220k was treated with ethanol-acetone or 1 M acetic acid, its activity increased more than 10-fold. Growth inhibitors were extracted with acid-ethanol from various tissues of rats. The activities of the extracts to inhibit the growth of BRL cells were high in spleen, lung and tumors with relatively high mitotic activities, but low in muscle, heart and brain. Acid-ethanol extract from BRL cells showed growth inhibitory activity toward BRL cells themselves significantly higher than that from RSV-BRL cells. The serum-free media conditioned with BRL and RSV-BRL cells showed a little growth inhibitory activity toward BRL cells. On treatment with acetic acid, their activities increased significantly, comparable for both types of cells. The media thus activated inhibited the growth of BRL cells, but not that of RSV-BRL cells. All the growth inhibitors described above including human platelet inhibitor, whether present in extracts or purified, resembled one another in stability against acid, heat and reducing reagents.

Animals↗