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Biomedical subjects

B Zhang

Publications and source records attributed to B Zhang.

At least 613 records · Page 34Linked to original sources
PubMed1993

Clinicopathologic analysis of 60 cases of basal cell carcinoma.

An analysis of 60 cases of basal cell carcinoma is reported. Among the 60 patients were 29 men and 31 women (1:1.1). Their ages ranged from 22 to 88, with an average of 58.8 years. The courses were from 2 months to more than 20 years, with 50% being less than 5 years. The head and face were the main sites involved. The etiology, clinical appearance, pathologic classification, and clinical therapy of the basaloma are discussed briefly. To minimize the patient's psychological burden, and according to the low rate of metastasis, we suggest that the tumor be designated basaloma or basal cell epithelioma rather than basal cell carcinoma.

Adult↗
PubMed1993

[A matched case-control study on 87 cases of congenital malformations].

In order to investigate the risk factors of congenital malformations, a case-control study on congenital malformations with 87 matched pairs was carried out in hospitals of Yinchuan area. The results showed that the risk factors of the congenital malformations in this area were mainly nocuous mental stimulation during early pregnancy, hyperemesis gravidarum, parturient personality (high scores of psychoticism and neuroticism), degree to parturient education and exposure to other detrimental factors in early pregnancy, smoking habit of neonate's father, and so on.

Case-Control Studies↗
PubMed1993

Long-term administration of probucol and QTc interval prolongation.

Electrocardiographic QTc intervals were measured in twenty-one hypercholesterolemic patients before and after long-term probucol (500-1,000 mg/day for 30 months) treatment. Probucol reduced serum total cholesterol (TC), triglyceride (TG), and high density lipoprotein-cholesterol (HDL-C). Mean QTc interval prolongation after probucol was 17 msec. A positive correlation was found between the change in QTc interval after probucol (delta QTc) and the total amount of probucol administered. delta QTc was negatively correlated to the pre-treatment QTc interval. No correlation was observed between serum probucol concentrations and delta QTc. Neither clinical evidence of cardiotoxicity nor critical arrhythmias were noted during the treatment period.

Aged↗
PubMed1992

The insulin receptor-related receptor. Tissue expression, ligand binding specificity, and signaling capabilities.

In 1989, Shier and Watt identified a gene which was predicted to encode a new member of the insulin receptor (IR) family, and they called it the insulin receptor-related receptor (IRR) (Shier, P., and Watt, V. M. (1989) J. Biol. Chem. 264, 14605-14608). However, the tissues expressing this receptor, its ligand binding specificity and its signaling capability have remained unknown. In the present studies we report Northern blot analyses and polymerase chain reaction data, which indicate that the IRR mRNA is expressed in a variety of tissues, including the human kidney, heart, skeletal muscle, liver, and pancreas. In order to examine the ligand(s) recognized by IRR, we constructed a chimeric receptor with the extracellular domain of the IR replaced with that of IRR. This chimera was found not to bind radioactively labeled insulin, insulin-like growth factor I (IGF-I), or IGF-II. These ligands and relaxin, the only other known member of the mammalian insulin family, also failed to stimulate the tyrosine kinase activity of this chimeric receptor. A second chimeric receptor with the extracellular domain of IR and the kinase domain of IRR was also constructed and utilized to study the signaling capabilities of the kinase domain of IRR. This chimera exhibited high affinity insulin binding and insulin-stimulated tyrosine kinase activity. The kinase domains of the IR and IRR were found capable of phosphorylating the same spectrum of exogenous and endogenous substrates. However, Chinese hamster ovary (CHO) cells stably overexpressing the kinase domain of IRR exhibited elevated basal thymidine incorporation and 2-deoxyglucose uptake compared with CHO cells and CHO cells overexpressing wild-type IR. We conclude that: 1) IRR is expressed in the human kidney, heart, skeletal muscle, liver, and pancreas, 2) IRR does not appear to be the receptor of any known member of the insulin family, and 3) the tyrosine kinase of IRR appears to be similar to that of IR in both the spectrum of substrates phosphorylated and the biological responses stimulated.

1-Phosphatidylinositol 4-Kinase↗
PubMed1992

Identification of a peroxisome proliferator-responsive element upstream of the gene encoding rat peroxisomal enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase.

Ciprofibrate, a hypolipidemic drug that acts as a peroxisome proliferator, induces the transcription of genes encoding peroxisomal beta-oxidation enzymes. To identify cis-acting promoter elements involved in this induction, 5.8 kilobase pairs of promoter sequence from the gene encoding rat peroxisomal enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase (EC 4.2.1.17/EC 1.1.1.35) was inserted upstream of a luciferase reporter gene. Transfection of this expression vector into rat hepatoma H4IIEC3 cells in the presence of ciprofibrate resulted in a 5- to 10-fold, cell type-specific increase in luciferase activity as compared to cells transfected in the absence of drug. A peroxisome proliferator-responsive element (PPRE) was localized to a 196-nucleotide region centered at position -2943 from the transcription start site. This PPRE conferred ciprofibrate responsiveness on a heterologous promoter and functioned independently of orientation or position. Gel retardation analysis with nuclear extracts demonstrated that ciprofibrate-treated or untreated H4IIEC3 cells, but not HeLa cells or monkey kidney cells, contained sequence-specific DNA binding factors that interact with the PPRE. These results have implications for understanding the mechanisms of coordinated transcriptional induction of genes encoding peroxisomal proteins by hypolipidemic agents and other peroxisome proliferators.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1992

A panel of monoclonal antibodies for the type I insulin-like growth factor receptor. Epitope mapping, effects on ligand binding, and biological activity.

We obtained 20 mouse monoclonal antibodies specific for human type I insulin-like growth factor (IGF) receptors, using transfected cells expressing high levels of receptors (IGF-1R/3T3 cells) as immunogen. The antibodies immunoprecipitated receptor.125I-IGF-I complexes and biosynthetically labeled receptors from IGF-1R/3T3 cells but did not react with human insulin receptors or rat type I IGF receptors. Several antibodies stimulated DNA synthesis in IGF-1R/3T3 cells, but the maximum stimulation was only 25% of that produced by IGF-I. The antibodies fell into seven groups recognizing distinct epitopes and with different effects on receptor function. All the antibodies reacted with the extracellular portion of the receptor, and epitopes were localized to specific domains by investigating their reaction with a series of chimeric IGF/insulin receptor constructs. Binding of IGF-I was inhibited up to 90% by antibody 24-60 reacting in the region 184-283, and by antibody 24-57 reacting in the region 440-586. IGF-I binding was stimulated up to 2.5-fold by antibodies 4-52 and 16-13 reacting in the region 62-184, and by antibody 26-3 reacting downstream of 283. The latter two groups of antibodies also dramatically stimulated insulin binding to intact IGF-1R/3T3 cells (by up to 50-fold), and potentiated insulin stimulation of DNA synthesis. Scatchard analysis indicated that in the presence of these antibodies, the affinity of the type I IGF receptor for insulin was comparable with that of the insulin receptor. These data indicate that regions both within and outside the cysteine-rich domain of the receptor alpha-subunit are important in determining the affinity and specificity of ligand binding. These antibodies promise to be valuable tools in resolving issues of IGF-I receptor heterogeneity and in studying the structure and function of classical type I receptors and insulin/IGF receptor hybrids.

3T3 Cells↗
PubMed1992

Substrates and signalling complexes: the tortured path to insulin action.

In the last few years several potential substrates of the insulin receptor tyrosine kinase have been identified, purified, and their cDNAs isolated. These putative substrates include: 1) pp15, a fatty acid-binding protein; 2) pp120, a plasma membrane ecto-ATPase; 3) pp42, a MAP serine/threonine kinase; 4) pp85, a subunit of the Type 1 phosphatidylinositol kinase; and 5) pp185, a phosphatidylinositol kinase binding protein. Although the tyrosine phosphorylation of several of these substrates correlates with the signalling capabilities of various mutant receptors, the role of these substrates in mediating any one of insulin's many biological responses is still unknown. In addition, recent data indicate that the tyrosine phosphorylation of pp42 may in fact be due to autophosphorylation, thereby removing it from the list of putative substrates of the insulin receptor kinase. Finally, the present review discusses the question of whether signalling occurs as a result of the tyrosine phosphorylation of substrates or via the formation of signalling complexes.

1-Phosphatidylinositol 4-Kinase↗
PubMed1992

Low-molecular-weight heparin exerts an early antithrombotic effect in small arteries and veins following severe trauma.

Administration of low-molecular-weight heparin (LMWH) and standard heparin was studied by evaluating vessel bleeding, patency, and thrombotic material following severe vascular trauma. Arteriotomy and intimectomy or venotomy and intimectomy were performed on small rabbit arteries or veins in two separate blinded studies. All vessels were closed using a continuous microvascular suture. Patency and weight of thrombotic materials were evaluated 2 hr after reperfusion. In the arterial study, two groups of 23-24 arteries were treated with saline or LMWH systemically. Bleeding times were 89 +/- 15 sec in the control group and 103 +/- 27 sec in the LMWH group; there was no significant difference between the groups. Patency was significantly increased in the LMWH group (79%) compared to the control group (52%). The weight of thrombotic material in the LMWH group (1.39 +/- 0.20 mg per artery) was significantly different compared to the control group (2.19 +/- 0.22 mg per artery). In the venous study, 65 veins were divided into three groups (21-23 vessels/group) and treated with systemic saline, heparin, or LMWH. Bleeding times in the conventional heparin group (37 +/- 7 sec), the control group (23 +/- 3 sec), and LMWH group (22 +/- 4 sec) were not significantly different. The patency rates were significantly increased in the heparin (42%) and LMWH (39%) groups compared to the control group (0%). The weight of thrombotic material in each vein was significantly less in the LMWH (1.07 +/- 0.24 mg) and heparin (1.78 +/- 0.52 mg) groups than in the control group (3.78 +/- 0.29 mg).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Detection and analyses by gel electrophoresis of cisplatin-mediated DNA damage.

DNA damage induced by cis-diamminedichloroplatinum (II) (cisplatin: cis-DDP), an anticancer drug, was studied in vitro by monitoring the drug-induced conformational change of pUC18 plasmid DNA, the sensitivity to some restriction enzymes of the damaged DNA and the sequence-dependent termination of DNA synthesis caused by cisplatin. Closed circular, superhelical pUC18 DNA was treated at 37 degrees C for 16 h with various concentrations of cisplatin. Cisplatin-dose-dependent conformational change due to unwinding of the treated DNA was detected by agarose gel electrophoresis. To analyze the base-specificity of the cisplatin damage, the measurement for sensitivity of cisplatin-treated DNA to various types of restriction enzyme and sequence gel analysis of the treated DNA were conducted. The results suggested that cisplatin attacked preferentially the sequence of GG > AG > GNG in the order. In the present assay condition, the cisplatin/DNA nucleotide ratios required for the DNA damage detection were roughly 0.025 for the conformational analysis, 0.001 or more for the restriction enzyme analysis, and less than 0.001 for the sequence gel analysis. By using the present method, it was demonstrated that the cisplatin-mediated DNA damage was inhibited by NaCl, KCl, CaCl2 or MgCl2 at their nearly physiological concentrations, and by reducing agents such as thiourea and 2-mercaptoethanol in the reaction mixture.

Base Sequence↗
PubMed1992

[Studies on the chemical constituents from the skin of Bufo bufo gargarizans Cantor].

Four bufotoxins were isolated by means of preparative reversed phase HPLC from the water soluble fraction of the skin of Bufo bufo gargarizans Cantor. On the basis of their spectral data (UV, IR, 1HNMR, 13CNMR, EIMS and FDMS), amino acid analyses and chemical properties, they were identified as bufotalin 3-succinoylarginine ester(I), bufalin 3-succinoylarginine ester(II), cinobufagin 3-succinoylarginine ester(III), and resibufogenin 3-succinoylarginine ester(IV). Compound I is a new bufotoxin.

Animals↗
PubMed1992

[A case of acute lymphocytic leukemia transformed from malignant lymphoma].

We report a case of malignant lymphoma in a 15-year-old male. He had erythema and nodular lesions, hepatomegaly, and splenomegaly with high fever for one month. Laboratory examination revealed a normal blood routine test, a few lymphomatic cells in the bone marrow, and histopathologic changes characteristic of malignant lymphoma in a skin biopsy. Two months later, a second bone marrow examination showed 90% prolymphoblasts. The peripheral blood count revealed WBC 108 x 10(9)/L; among these, prolymphoblasts accounted for 92%. The patient was diagnosed as acute lymphocytic leukemia, and died 2 days later. The diagnosis and transformation from malignant lymphoma to acute lymphocytic leukemia are discussed.

Adolescent↗
PubMed1992

Application of ABCD double feedback management in quality assurance of diagnostic radiology.

This method combines modern management and statistical methods with traditional film-reading systems to form a new retrospective and prospective film-reading system for quality assurance in X-ray diagnostic imaging. This method also provides feedback information with A, B, C, D and W factors which reflect the drawbacks of the radiographs. The ABCD double-feedback management system is an imaging quality evaluation system which concentrates on several important time and space periods in the radiographic engineering process. It incorporates adjustment of the X-ray apparatus and its functional capacity, selection of X-ray equipment, and application of the technician's experience and duty in the X-ray room and dark room.

Feedback↗
PubMed1992

[A 12-year clinical experience of cardiac valve replacement with domestic tilting disc valve prostheses in 1013 cases].

1013 patients with cardiac valve replacement during a 12-year period from 1978 to 1990 were reported. 566 cases were implanted with Shanghai-made tilting disc valve prostheses and 447 with Lanzhou-made (C-L valves). Mitral valve replacement (MVR) in 753 patients, aortic valve replacement (AVR) in 102 and double valves replacement (DVR) in 158. The overall early mortality rate was 6.2% with 4.9%, 7.8% and 11.3% after MVR, AVR and DVR respectively. Follow-up study was made in 3097.43 patient-year (mean 3.26 years). The late death rate was 1.6% patient-years and with 1.4, 1.8 and 3.2 after MVR, AVR and DVR respectively. The incidence of late valve-related complication (% patient-years) were: thromboembolism 0.39, anticoagulant-related hemorrhages 0.77, prostheses failure 0.22, prosthetic valve endocarditis 0.38, periprosthetic leak 0.12, and reoperations 0.38. The domestic tilting disc valve prostheses are considered to be qualified valves with low mortality and satisfactory results.

Adolescent↗
PubMed1992

Effects of Chinese herbal drugs on serum lipids, lipoproteins and apolipoproteins in mild to moderate essential hypertensive patients.

We investigated the effects of the traditional Chinese herbal drugs, Dai-saiko-to (D) and Saiko-ka-ryukotsuboreito (S) on blood pressure, pulse rates, serum lipids, lipoproteins and apolipoproteins in 30 patients with mild to moderate hypertension in an open, randomised trial. After the drug treatment, BP remained unchanged, but pulse rates declined significantly after 3 months in the S treated group. Serum total cholesterol and triglyceride values did not change, but high density lipoprotein-cholesterol increased significantly (P < 0.05) in both groups. Apo-AI (P < 0.1 in S group) and apo-AII (P < 0.05 in D group, P < 0.1 in S group) tended to increase 3 months after treatment. These data indicate that both of these traditional Chinese medicines have a preferential effect on lipid metabolism with little antihypertensive action.

Apolipoproteins↗
PubMed1991

Insulin-stimulated serine and threonine phosphorylation of the human insulin receptor. An assessment of the role of serines 1305/1306 and threonine 1348 by their replacement with neutral or negatively charged amino acids.

Insulin promotes insulin receptor beta-subunit phosphorylation on tyrosine, serine, and threonine residues in a variety of cells, including simian COS cells which transiently express human insulin receptors following transfection with a cDNA encoding the wild-type receptor protein. To examine the potential roles of serines 1305 and 1306 and threonine 1348 as sites of insulin-stimulated phosphorylation in these cells, these residues (i.e. either serines 1305 and 1306, or threonine 1348) were replaced with neutral (alanine) or negatively charged (aspartate) amino acids. Following transient expression of each of these mutant receptors in COS cells, two-dimensional phosphopeptide mapping reveals that threonine 1348 is the major, if not the only, insulin-stimulated threonine phosphorylation site. In contrast, while serines 1305 and/or 1306 are phosphorylated in an insulin-dependent manner, these sites comprise only a minor proportion of insulin receptor serine phosphorylation in these cells. Substitution of either serines 1305 and 1306 or threonine 1348 with neutral or negatively charged amino acids has no effect on insulin-stimulated tyrosine autophosphorylation of these mutant receptors in intact cells. Furthermore, insulin-stimulated exogenous protein-tyrosine kinase activity of the mutant receptors is unaffected, as assessed following either phosphorylation of receptors in intact cells or following immunopurification of receptors and their autophosphorylation in vitro.

Amino Acid Sequence↗
PubMed1991

A region of the insulin receptor important for ligand binding (residues 450-601) is recognized by patients' autoimmune antibodies and inhibitory monoclonal antibodies.

Chimeric receptors containing different portions of the homologous human insulin receptor, insulin-like growth factor I receptor, and insulin receptor-related receptor were utilized to identify the epitopes recognized by various anti-insulin receptor antibodies. The antibodies studied included 12 monoclonal antibodies to the extracellular domain of the human insulin receptor as well as 15 patients' sera with autoimmune anti-insulin receptor antibodies. All of the patients' sera and all 8 monoclonal antibodies that inhibit insulin binding were found to recognize an epitope contained within residues 450-601 of the alpha subunit of the receptor. In contrast, 2 monoclonal antibodies that do not inhibit insulin binding were found to recognize the cysteine-rich region of the alpha subunit. Chimeric insulin receptors that had residues 450-601 replaced with the homologous residues of the insulin-like growth factor I receptor exhibited a decreased ability to bind insulin. In contrast, insulin-like growth factor I receptors that have had the comparable region replaced with that of the insulin receptor showed no decrease in their ability to bind ligand. These results indicate that residues 450-601 of the insulin receptor are important for insulin binding and include the major site for recognition by inhibitory monoclonal antibodies and patients' autoimmune anti-receptor antibodies.

Antibodies, Monoclonal↗