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Biomedical subjects

G H Yang

Publications and source records attributed to G H Yang.

At least 37 records · Page 2Linked to original sources
PubMed1996

Pioglitazone attenuates the inhibitory effect of phorbol ester on epidermal growth factor receptor autophosphorylation and tyrosine kinase activity.

A new anti-diabetic drug, pioglitazone, was tested as to whether it could ameliorate the decreased kinase activity of epidermal growth factor (EGF) receptor induced by phorbol ester (PMA) in A431 cells. The treatment of A431 cells with PMA decreased the tyrosine kinase activity of EGF receptors to 37% of normal in autophosphorylation and to 24% in tyrosine kinase activity toward Glu/Tyre synthetic polymers. Co-incubation of the cells with pioglitazone and PMA improved the receptor tyrosine kinase activity to 81% of control. Pioglitazone treatment alone did not change the kinase activity of EGF receptors. Pioglitazone did not decrease the PMA-activated protein kinase C activity and did not affect the protein tyrosine phosphatases activity in A431 cells. These results suggest that pioglitazone may act as a specific antagonist to the inhibitory effect by protein kinase C on the EGF receptor tyrosine kinase.

Carcinoma, Squamous Cell↗
PubMed1996

Organization and nucleotide sequence of genes for hemagglutinin components of Clostridium botulinum type B progenitor toxin.

The genes for hemagglutinin components (33 kD, 17 kD, and 21.5 kD) of Clostridium botulinum type B progenitor toxin were cloned and sequenced. Analysis of the nucleotide sequence showed that the 33 kD, 17 kD, and 21.5 kD hemagglutinin genes were organized into an operon in the 5'upstream region of the toxin gene and their ORF orientation were opposite to that of the toxin gene. A comparison of amino acid sequences between the hemagglutinin components in type B and type C progenitor toxin showed significant homology. Northern blot analysis also revealed that all of the genes for the hemagglutinin components were transcribed as a polycistronic RNA.

Amino Acid Sequence↗
PubMed1996

[Priorities of disease control in China--analysis on mortality data of National Disease Surveillance Points System].

The leading health problems in the Chinese population are analyzed with indices as standard death rate, YPLL and DALY, using data from The Chinese Diseases Surveillance Points System (DSP). Disease pattern in China is different from that in the 1950's owing to demographic transition (aging of the population), decrease of both morbidity and mortality of communicable disease etc. That made chronic disease relatively more important the increase of some risk factors, directly cause the rising of mortality and morbidity of some chronic diseases and injuries related to lung cancer and transportation. At present the character of the disease pattern is as follows: there is still a long way to go to control communicable diseases, although the incidence rates and proportion have decreased. Meanwhile, chronic diseases and injuries are becoming major health issues. Hence, China is facing double challenges.

Accidents↗
PubMed1995

An extracellular domain of the beta subunit is essential for processing, transport and kinase activity of insulin receptor.

The extracellular portion of the insulin receptor (IR) beta-subunit has four cysteine and four asparagine residues which are potentially involved in disulphide bond formation between the alpha- and beta-subunits and N-linked glycosylation respectively. However, the function of this portion is not fully understood. In order to investigate the role of the extracellular domain of beta-subunit, we created a deletion mutant of IR cDNA which lacked 47 amino acid residues encoded by 141 bp corresponding to exon 13 of the IR gene. Insulin binding and surface labelling of COS 7 cells transiently expressing the mutant insulin receptors (IR delta Ex13) showed that the mutated receptors were not expressed on the cell surface. However, immunoblot analysis showed that uncleaved form (190 kDa) of the mutant receptors were intracellularly expressed. Deglycosylation with endoglycosidase H showed that the mutant receptors had mainly high-mannose oligosaccharide chains. The mutant IRs bound with high affinity to lentil lectin but with low affinity to wheat germ agglutinin. Therefore, it is suggested that misfolding of the mutant receptors inhibits transport to the Golgi apparatus where processing of oligosaccharide chains, as well as proteolytic cleavage into subunits, takes place. The binding affinity of the mutant receptors for insulin was 50% of normal. Furthermore, insulin-stimulated autophosphorylation of IR delta Ex13 was markedly impaired. These data provide the evidence for a critical role of the extracellular domain of IR beta-subunit for processing and transport as well as the intramolecular signal transduction to activate IR tyrosine kinase.

Base Sequence↗
PubMed1994

Leu 193 mutation in the cysteine rich region of the insulin receptor inhibits the cleavage of the insulin receptor precursor but not insulin binding.

To characterize the Leu 193 mutant insulin receptor, which was found in a patient with extreme insulin resistance, the mutant insulin receptor was overexpressed in Rat-1 fibroblasts by transfection of mutated insulin receptor cDNA. In the pulse-chase experiment, the cleavage of the proreceptors to the matured receptor subunits was impaired in the cells expressing Leu 193 insulin receptor and therefore, the mutant proreceptors were accumulated in the cell. Insulin bound to the Leu 193 insulin receptor on the cell surface with normal affinity, although the mutation was in the alpha-subunit of the insulin receptor. Therefore, the Leu 193 mutation impaired proreceptor cleavage but not insulin binding.

Animals↗
PubMed1994

[Nuclear morphometric analysis of colorectal adenocarcinoma and its clinicopathologic significance].

A nuclear morphometric analysis was performed on the histologic sections of 64 colorectal adenocarcinomas with a 5-year follow-up. The parameters selected in this study were nuclear area (NA), nuclear perimeter (NP), standard deviation of nuclear area (SDNA), nuclear volume (NV), nuclear diameter of an equivalent circle (ND). No clear correlation was found between the five parameters and the clinicopathologic data of colorectal adenocarcinomas. The five parameters were important prognostic factors in colorectal adenocarcinomas. It was found that the grade II colorectal adenocarcinomas were a heterogenous group and could be divided prognostically into various subgroups by nuclear morphometry.

Adenocarcinoma↗
PubMed1993

Effect of subconjunctival daunorubicin on glaucoma surgery in rabbits.

Daunorubicin (DNR), an antibiotic-antimetabolite, was used as an adjunct to standardized partial-thickness filtration surgery in 21 rabbits to determine its effects on that surgery. Postoperatively, one of the eyes of each rabbit received subconjunctival injections of DNR 25 micrograms or 50 micrograms, while the fellow eyes received only diluent, daily for 2 to 14 days. Bleb survival, fistula patency, the thickness of the subconjunctival connective tissue, and postoperative complications were investigated. The filtration blebs lasted significantly longer (P < .005), the rate of fistula closure was significantly lower (P < .005), and the subepithelial connective tissue was much looser and thicker in the experimental eyes than in the control eyes. Corneal toxicity occurred more frequently in the eyes treated with the higher-dose DNR than in those treated with the lower dose and in the control eyes.

Animals↗
PubMed1990

Medicinal protection with Chinese herb-compound against radiation damage.

Experiments were carried out on mice and the subjects irradiated for cancer therapy to evaluate the protective efficacy of a Chinese medicinal herb-compound (CMHC). The lethality and the degree of leucopenia caused by radiation in mice medicated with CMHC were significantly less in comparison with control mice (p less than 0.01 and p less than 0.001, respectively). CMHC significantly improved the WBC and the thrombocytes in irradiated workers (p less than 0.01 and p less than 0.001, respectively). The WBC count of 40 patients under radiotherapy while treated with CMHC recovered from 3450 +/- 77/c.mm to 5425 +/- 264/c.mm (p less than 0.001); whereas, in the control group, without any medication, the WBC count dropped significantly (p less than 0.001). Our results revealed the applicabilities of CMHC in protection against radiation damage in spaceflight and in other fields.

Animals↗
PubMed1989

[Selection of treatment modality for developmental glaucoma].

53 cases of developmental glaucoma were analyzed with regard to results of treatment and factors involved. Poor compliance was found a major problem, and a number of patients did not respond well to medical treatment. Surgical intervention was indicated for patients with (1) unsatisfactory medical control of IOP, (2) inadequate recognition of the severity of their case, (3) inaccessibility to prompt treatment when needed, (4) occurrence of progressive visual field defects and optic disk damages, and (5) the other eye already in the terminal stage of glaucoma.

Adolescent↗
PubMed1989

[Experimental study of a decoction of yiguan jian].

In this paper, the decoction of Yiguan Jian is reported to have significant fatigue-resisting, hypoxia-resisting, antiinflammatory, sedative, analgesic, extracorporal bacterio-static actions, and also to strengthen the phagocytosis of Phagocytes. Besides, the drug can antagonize acetylcholine-induced spasm of isolated intestinal muscles in rabbits. The decoction has proved safe for use. This study provides some experimental basis for clinical use in nourishing yin, invigorating the liver and treating many diseases.

Animals↗
PubMed1989

[Primary study of histogenesis and diagnosis of synoviosarcoma].

Fourteen cases of synoviosarcoma were investigated by electron microscopy and immunohistochemical technique (PAP) using keratin and EMA as epithelial markers, vimentin as a mesenchymal marker. Of the 14 cases 9 were biphasic (BS) and 5 were monophasic synoviosarcoma (MS). In BS, epithelial-like cells, glandular, tubular of slit-like structures, junctional complex, microvilli at the luminar surface and basal lamellae at bottom could be easily seen. Spindle cells both in BS and MS were similar. These cells had somewhat similarity with epithelia-like cells, such as slender cell processes or microvilli, the external lamellae and cell junctions. The spindle cells also formed some slit-like structures. Collagenization was mild in matrix. Whether in BS or MS, epithelial or spindle cells, there were positive reactions for keratin, EMA and vimentin. The present study suggests that synoviosarcoma is neither a tumor of synovium origin nor a sarcoma of synovial differentiation, but a carcinosarcoma or adenosarcoma of soft tissues; the monophasic type is not a variant of fibrosarcoma either. It really is a distinct variant of synoviosarcoma. The expressions of both epithelial and mesenchymal features are useful criteria for diagnosis of synoviosarcoma.

Humans↗