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Biomedical subjects

H Gao

Publications and source records attributed to H Gao.

At least 181 records · Page 10Linked to original sources
PubMed1996

Immunostimulating polysaccharides from Panax notoginseng.

PURPOSE: The main purpose of this study is to prepare and characterize polysaccharides from Panax notoginseng, investigate their effects on immune system in vitro in order to find new immunostimulants for the prevention and supporting treatment of infection and immunodeficiency related diseases. METHODS: Polysaccharides were extracted with aqueous solution, separated with column chromatography. Their anticomplementary activities were investigated by using human serum and antibody-sensitized sheep red blood cells. Interferon-gamma and tumor necrosis factor inductive activities were studied by using isolated mouse spleen lymphocytes and peritoneal macrophages, respectively. RESULTS: Four polysaccharides, homogeneous in gel-filtration chromatography, were prepared and designated PF3111, PF3112, PBGA11, and PBGA12. Component sugar analysis revealed that they are heteroglycans with MWs ranging from 37 kD to 760 kD, composed of glucose, galactose, arabinose, mannose, and xylose in different molar ratios. Fraction PBGA12 has the most anticomplementary activity which is mediated through both alternative and classical pathways. All the polysaccharides except PBGA11 induced the production of interferon-gamma in the presence of concanavalin A. They induced the production of significant amount of TNF-alpha in cell cultures. CONCLUSIONS: The polysaccharides from P.notoginseng have immunostimulating activities in vitro.

Adjuvants, Immunologic↗
PubMed1996

Hypoxia/reoxygenation selectively impairs alpha 1b-adrenoceptor function in small mesenteric arteries.

The present study examined whether hypoxia/reoxygenation (H/R) attenuates norepinephrine (NE) effectiveness in small arteries by interfering with function of alpha 1a- and/or alpha 1b- adrenoceptor subtypes. Small mesenteric arteries (approximately 150 microns) were obtained from rats mounted on a small vessel myograph in oxygenated physiological salt solution (PSS), and the relationship between NE concentrations and contractile tension was assessed. Hypoxia was induced by bubbling the vessels with 95% N2-5% CO2 for 15 min. Vessels were then reoxygenated for 30 min, and NE responses were reevaluated. Superoxide dismutase (SOD) and catalase (CAT) were added to the PSS in one group of vessels to investigate the role of reactive oxygen metabolites. In other groups, alpha 1b-receptors were blocked with chloroethylclonidine and alpha 1a-receptors were blocked with 5-methylurapidil or WB-4101 to produce exclusive alpha 1a- or alpha 1b-responses to NE. H/R decreased the NE negative logarithm of the mean effective concentration (pD2: i.e., -log[EC50], where EC50 is mean effective concentration) from 6.26 +/- 0.24 to 5.84 +/- 0.12 (P < 0.05). SOD and CAT prevented the H/R-induced contractile dysfunction. alpha 1a-Receptor responses to NE were not altered by H/R. In contrast, alpha 1b-receptor responses were significantly attenuated after H/R. The results indicate that alterations in NE responsiveness after H/R are due to dysfunction of the alpha 1b signal transduction pathway.

Adrenergic alpha-Antagonists↗
PubMed1996

The efficiency of respiratory muscle strengthening training programs in pilots.

OBJECTIVE: To evaluate the efficiency of respiratory muscle training programs in pilots. METHODS: Twenty-four male pilots were divided into two groups. The training group (12 pilots) underwent respiratory strengthening training programs besides routine physical exercises. The other 12 pilots in the control group only did routine physical exercises, but the training time was the same in these two groups. Before and after training programs in the two groups, the respiratory muscle functions were examined. RESULTS: 24 pilots in these two groups completed training programs within four weeks. The pilots in the training group got improvement of respiratory muscle functions which was much better than those of the control group. CONCLUSION: It suggests that the strengthening training programs of respiratory muscles can improve and strengthen the respiratory muscle functions in pilots.

Adult↗
PubMed1996

[The protective effect of nicotinamide on interleukin-1 beta induced damage to rat islets of Langerhans and its mechanism].

OBJECTIVE: To investigate the protective effects of nicotinamide (NA) on newborn rat islets of Langerhans. METHODS: Newborn rat islets were isolated by digestion of collagenase V. The effects of IL-1 beta and/or NA on insulin release and nitric oxide (NO) production and 3H-thymidine incorporation were studied. RESULTS: NA had no effects on both accumulated insulin release and insulin release at an acute glucose challenge, but increased 3H-thymidine incorporation. 25 mmol/L of NA reduced the inhibition of accumulated insulin release and 3H-thymidine incorporation induced by 40/ml of IL-1 beta. However. NA was not able to reverse the reduced ability of IL-1 beta-treated islets to respond to an acute glucose challenge. NA dose-dependently reduced NO production induced by IL-1 beta. CONCLUSION: There is the protective effect of NA on IL-1 beta-induced damage to islets of Langerhans. The mechanism of this effect might be related to that NA stimulates islet cells replication and reduces NO production induced by IL-1 beta.

Animals↗
PubMed1996

[Difference of the discharges from the postganglionic fibers of the celiac ganglion induced by electroacupuncture at zusanli and yanglingquan].

The changes of the discharge from postganglionic fibers of the celiac ganglion induced by electroacupuncture (EA) at Zusanli and Yanglingquan were measured on 25 healthy rabbits. The result shows that the sympathetic activity can be inhibited by EA at both acupoints above. The depression of the sympathetic activity resulted from EA at Zusanli was significant stronger than that at Yanglingquan (P < 0.05). This result indicates that there is the relative individuality in the function of the different acupoints on the different channels.

Acupuncture Points↗
PubMed1996

[Functional evaluation of the mitochondria from Warthin tumor].

The mitochondria were isolated from 8 surgical specimens of Warthin tumor of the parotid and the activity of the respiration was evaluated. The average respiratory control rate (RCR) of the mitochondria of the tumors (1.12 +/- 0.50) was lower than that of the normal mitochondria (2.10 +/- 0.75). The preliminary experiment showed a loosely coupled state of oxidative phosphorylation. It indicates that the hyperplasia of the mitochondria in the Warthin tumor results from the metabolic disturbance of the tumor and it is a compensation in the cellular level.

Adenolymphoma↗
PubMed1995

Circulation of oligonucleotides by disulfide bridge formation.

An effective, convenient method for the circularization of oligonucleotides has been developed. This procedure involved preparation of an oligonucleotide with backbone-linked 5'- and 3'-terminal hexamethylenethiol groups, followed by oxidation of the thiol groups with air of oxygen to produce the corresponding circular sequence bridged via a bis(hexamethylene)-disulfide moiety. The method has been applied to the circularization of oligodeoxynucleotide sequences of varying lengths (5, 10, 15, 20, 30 and 40 bases), and the circularization process was highly efficient as shown by HPLC or gel electrophoresis of the crude reaction mixtures. Competing reactions such as dimerization were not significant except for the longer sequences (30 and 40 bases). The circularization of an eight base RNA sequence was also accomplished, as well as hexa-ethylene glycol bridged poly-T sequences capable of triplex formation.

Base Sequence↗