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Biomedical subjects

H Yang

Publications and source records attributed to H Yang.

At least 973 records · Page 54Linked to original sources
PubMed1990

Plant regeneration from protoplasts of a super Chinese rice (Oryza sativa L.) cultivar--Zhonghua NO.8.

Green rice plants were regenerated from protoplasts, which were derived from cell suspension of Oryza sativa L. cut. Zhonghua No. 8, a super Chinese rice cultivar with high productivity, good quality and high resistance to both bacterial blight and blast. The embryogenic calli were initiated from mature embroys. It took about 4 months to establish the cell suspenion. The regeneration plants from protoplasts were obtained in 2 months after the isolation of protoplasts.

Cells, Cultured↗
PubMed1990

[Degradation of acetonitrile by Acinetobacter sp. 51-2].

A strain of Acinetobacter sp. 51-2 was capable of degrading acetonitrile and utilizing various nitrile compounds, such as propionitrile, butyronitrile, acrylonitrile and so on. The ability and speed of degrading acetonitrile were quite strong and fast. Strain 51-2 could degrade 25 g/L acetonitrile in 48 h by adapted cells. The efficiency of degrading acetonitrile was closely related to the conditions of culturing bacterial cells. The reaction temperature and present metals appeared to have a little effect on degradation of acetonitrile.

Acetonitriles↗
PubMed1990

The frequencies and doses of medical exposure in China.

A sampling survey of medical exposure frequency covered 15,000 hospitals in 24 provinces, while a sampling measurement of patient doses covered 2,000 hospitals in 14 provinces. From these surveys and measurements, we compiled survey data of 11 million cases. The data were analyzed by computer, and the frequencies, averages of skin and organic dose per examination, and population doses per capita (He, LSD, GSD, SSD) were found. The possible risks of medical exposure in China are also estimated in this paper.

Adolescent↗
PubMed1990

[Application of ion chromatography to identification of anaerobic bacteria].

The fatty acids of anaerobic bacteria were detected by ion chromatography (IC). The results showed that 11 kinds of standard fatty acids could be analyzed within 15 min, and just needed 1 injection sample. The fatty acids patterns of 40 strains of anaerobic bacteria detected by IC were essentially the same as that by gas chromatography (GC) reported by VPI. In comparison with GC, IC has further advantages: pretreatment is simpler, both volatile and non-volatile fatty acids can be analyzed at the same time, and formic and lactic acid can be well analyzed.

Bacteria, Anaerobic↗
PubMed1989

Infusion of human insulin-like growth factor I (IGF-I) into malnourished rats reduces hepatic IGF-I mRNA abundance.

To determine whether the serum level of IGF-I influences its hepatic synthesis through negative feedback regulation, we infused 200 micrograms/d of human IGF-I subcutaneously into young male rats eating either an energy-restricted or ad lib diet. In energy-restricted rats, a two-fold increase in serum IGF-I concentration produced a 41% increase in growth rate at the end of one week, and a 30% decrease in steady state hepatic IGF-I mRNA and 56% drop in serum GH at the end of two weeks. In ad lib fed rats, the increased serum IGF-I concentration neither enhanced growth rate nor significantly reduced hepatic IGF-I mRNA abundance or serum GH levels. These data suggest that the abundance of hepatic IGF-I mRNA in energy-restricted rats is controlled, in part, by serum IGF-I levels via negative feedback regulation.

Animals↗
PubMed1989

Active specific immunotherapy with antiidiotypic antibodies in patients with solid tumors.

Tumor-associated antigens (TAA) provide appropriate targets for selective manipulation of the patient's immune response in the immunotherapy of cancer. Active specific immunotherapy utilizing antiidiotypic antibodies to anti-TAA antibodies has been implemented in phase I clinical trials both in patients with colorectal carcinoma and in those with melanoma. The theoretical basis for immunotherapy with antiidiotypic antibodies, the results of these clinical trials, and an evaluation of appropriate parameters for future clinical trials of active specific immunotherapy with antiidiotypic antibodies in patients with solid tumors are reviewed.

Animals↗
PubMed1989

Intrathecal injection of bombesin inhibits gastric acid secretion in the rat.

Bombesin (100-500 ng) injected intrathecally (T9-10) inhibited gastric acid secretion stimulated by pentagastrin and the GABAB agonist baclofen in urethane-anesthetized rats and basal gastric acid secretion in conscious, pylorus-ligated rats. Peptide action was dose-related, occurred within 30 min, and lasted for greater than 1 h. Bombesin-induced inhibition of pentagastrin-stimulated gastric acid secretion was not altered by cervical cord transection. Intravenous infusion of the monoclonal bombesin antibody 2A11 abolished intravenous bombesin (10 micrograms/kg.h)-induced 33% inhibition of gastric response to pentagastrin but did not alter intrathecal bombesin (200 ng)-induced 38% inhibition of gastric response to pentagastrin. The inhibitory effect of bombesin (200 ng) on pentagastrin-stimulated gastric secretion was reversed by bilateral adrenalectomy or removal of celiac and mesenteric ganglia. Intrathecal injections of rat calcitonin gene-related peptide, neuromedin B, neuromedin U, and the stable substance P analogue (pGlu5, MePhe8, MeGly9)-substance P(5-11) did not alter pentagastrin-stimulated gastric acid secretion. These results demonstrate that bombesin injected into the subarachnoid space of the spinal cord inhibits vagally stimulated and pentagastrin-stimulated gastric secretion in rats. Bombesin action is peptide specific, exerted at a spinal site, and expressed through the sympathetic nervous system.

Adrenalectomy↗
PubMed1989

Effect of gastrin monoclonal antibody 28.2 on acid response to chemical vagal stimulation in rats.

The role of gastrin in mediating the acid response to chemical vagal stimulation was evaluated by intravenous injection of the gastrin monoclonal antibody 28.2 (2.6 mg/rat). The antibody was injected 30 min prior to the administration of vagal stimulants in urethane-anesthetized rats equipped with a double lumen gastric cannula. The gastrin monoclonal antibody 28.2 prevented gastrin-17- but not carbachol-stimulated gastric acid secretion. The gastric acid response to vagal stimulation produced by thyrotrophin-releasing hormone (TRH) injected into the cisterna magna or the dorsal vagal complex and by the GABAB agonist, baclofen, infused intravenously was reduced by 33, 22 and 33% respectively in rats administered with gastrin monoclonal antibody 28.2. These immunoneutralization studies provide evidence that approximately 75% of the acid response to vagal stimulation is not mediated by gastrin in urethane-anesthetized rats.

Animals↗
PubMed1989

Synthesis and antiviral activity of several 2,5'-anhydro analogues of 3'-azido-3'-deoxythymidine, 3'-azido-2',3'-dideoxyuridine, 3'-azido-2',3'-dideoxy-5-halouridines, and 3'-deoxythymidine against human immunodeficiency virus and Rauscher-murine leukemia virus.

Several 2,5'-anhydro analogues of 3'-azido-3'-deoxythymidine (AZT), 3'-azido-2'3'-dideoxyuridine (AZU), 3'-azido-2'3'-dideoxy-5-bromouridine, 3'-azido-2',3'-dideoxy-5-iodouridine, and 3'-deoxythymidine and the 3'-azido derivative of 5-methyl-2'-deoxyisocytidine have been synthesized for evaluation as potential anti-HIV (human immunodeficiency virus) agents. These 2,5'-anhydro derivatives, compounds 13-17, demonstrated significant anti-HIV-1 activity with IC50 values of 0.56, 4.95, 26.5, 27.1, and 48 microM, respectively. Compared to that of the parent compounds AZT and AZU, the respective 2,5'-anhydro analogues, compounds 13 and 14, were somewhat less active. Whereas AZT was cytotoxic with a TCID50 of 29 microM, the toxicity of the 2,5'-anhydro derivative of AZT, compound 13, was reduced considerably to a TCID50 value of greater than 100 microM. The 2,5'-anhydro analogue of 5-methyl-2'-deoxyisocytidine also demonstrated anti-HIV-1 activity with an IC50 value of 12 microM. These compounds were also evaluated against Rauscher-Murine leukemia virus (R-MuLV) in cell culture. Among them, AZT, 3'-azido-2',3'-dideoxy-5-iodouridine, 3'-azido-2',3'-dideoxy-5-bromouridine, and 2,5'-anhydro-3'-azido-3'-deoxythymidine (13) were found to be most active, with IC50 values of 0.023, 0.21, 0.23, and 0.27 microM, respectively.

Antiviral Agents↗
PubMed1989

Autoradiographic study of smooth muscle cell proliferation in spontaneously hypertensive rats.

1. The rate of smooth muscle cell proliferation in age-matched 1-4-week-old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats was compared using autoradiography. 2. Labelling index, defined as labelled cells/sum of labelled and unlabelled cells x 1000, was obtained from perfusion-fixed superior mesenteric and large mesenteric arteries. 3. In the large mesenteric arteries, the smooth muscle cell labelling indices were similar between the SHR and WKY at all age groups, except at 1 week of age when the smooth muscle labelling index was higher in the SHR. 4. In the superior mesenteric arteries, labelling indices were similar between the rat strains at all age groups. 5. We conclude that, in the SHR, a rapid proliferation of smooth muscle cells in the large mesenteric arteries occurred during the first week of life. This resulted in a higher number of smooth muscle cell layers in the media of muscular arteries. 6. The increased proliferation may play a role in the subsequent development of hypertension in the SHR.

Animals↗
PubMed1989

Morphological and functional studies on microencapsulated human fetal pancreatic tissue.

Fifty human fetal pancreases of 4-6 months gestation obtained from legal abortions were microencapsulated with alginate, poly-lysine after culture for 4-7 days. The microcapsules were studied morphologically and functionally. Immunocytochemical staining for insulin indicated B-cells were morphologically intact at 48 days. Insulin and C-peptide of the culture medium measured with radioimmuno-assay (RIA) showed that the microcapsules still retained the function of insulin secretion after culture for 25 days. There was no statistical difference when compared with noncapsulated tissues. No exocrine function was detected as evidenced by the amylase determination. We conclude that microencapsulated human fetal pancreatic tissues retain viability in culture for more than 25 days and can be used as transplants in the treatment of diabetes mellitus.

Amylases↗
PubMed1989

The effect of edible black tree fungus (Auricuaria auricula) on experimental atherosclerosis in rabbits.

The effects of edible black tree fungus (BFF) compared with aspirin on serum lipid level and experimental atherosclerosis and thrombosis in rabbits were studied. The results showed that total serum cholesterol and B-lipoprotein of the BTF group were significantly decreased (P less than 0.01) than the aspirin group and the group with neither BTF nor aspirin. There were less aortic atherosclerotic plaque and intramyocardial arterial lumen stenosis in the BTF group. The development of thrombus and platelet aggregation and thromboxane TXB2 level were inhibited both in the BTF and aspirin group (P less than 0.01). These findings indicate BTF may be used as a healthy food in preventing atherosclerosis and coronary heart disease, but its mechanism requires further investigation.

Animals↗
PubMed1989

[Dynamic changes of superoxide dismutase in patients with myocardial infarction. A clinical study].

The activity of serum superoxide dismutase (SOD) was studied in 35 cases of acute myocardial infarction (AMI) and 12 cases of angina pectoris (AP). The results suggested that serum MnSOD activity reached its peak value (18.7 +/- 6.39) immediately after AMI attack and gradually dropped down on the second day. The activity was no more detected on the seventh day. The value of serum MnSOD in patients with AMI within 24 hours was significantly different (P less than 0.05) or very significantly different (P less than 0.01-0.001) from that in patients with AMI after 2 days and AP and in the control group. The positive rate of early diagnosis in the three groups was 100%, 71% and 66% respectively. It was found that the height of serum MnSOD activity was closely correlated with the seriousness of myocardial damage, therefore, serum MnSOD activity may be one of the sensitive indices for the early diagnosis of AMI. In has also certain clinical value in the judgement of the extent of infarction and of prognosis.

Aged↗