Biomedical subjects

J Z Zhang

Publications and source records attributed to J Z Zhang.

At least 19 recordsLinked to original sources

PubMed1995

Prostaglandin I1 analogues, SM-10902 and SM-10906, affect human keratinocytes and fibroblasts in vitro in a manner similar to PGE1: therapeutic potential for wound healing.

The newly synthesized prostaglandin (PG) I1 analogues, SM-10902 and SM-10906, were compared with PGE1 in terms of their biological effects on cultured normal human keratinocytes (NHKs) and human dermal fibroblasts (HDFs) in order to evaluate their therapeutic potential for cutaneous wound healing. The PGI1 analogues had a direct effect on cell proliferation of HDFs as did PGE1, but inhibited cell growth of NHKs in contrast to the stimulatory effect observed with PGE1. In contrast to NHKs stimulated with PGI1 analogues, which exhibited low levels of adenosine 3,5-cyclic monophosphate (cAMP). HDFs stimulated with these analogues responded in a dose-dependent manner with extremely high levels of cAMP. Conditioned media (CM) derived from media in which HDFs had been incubated with both the PGI1 analogues promoted NHK proliferation. HDF production of interleukin (IL)-6 increased in response to the PGI1 analogues. Since IL-6 was shown to promote cell growth of NHKs, enhancement of NHK proliferation by CM was thought to be due to IL-6 derived from HDFs stimulated with the PGI1 analogues.

Alprostadil↗

PubMed1995

Secretory component (polymeric immunoglobulin receptor) as an intrinsic inhibitor of biological functions of interferon gamma in keratinocytes.

Secretory component (SC) acts as a transmembrane polymeric immunoglobulin receptor of epithelial cells and is known to bind to polymeric IgA and to contribute to the secretion of secretory IgA (sIgA). We describe a new biological function for free SC (FSC) by which the expression of intercellular adhesion molecule-1 (ICAM-1) and HLA-DR induced by interferon gamma (IFN gamma) is inhibited in human keratinocytes. This activity coincided with suppression of adenosine cyclic 3,5-monophosphate (cyclic AMP) production in keratinocytes. Keratinocytes produced SC after stimulation with IFN gamma and this production was suppressed by the addition of H-7 or propranolol. The addition of propranolol resulted in prolongation of ICAM-1 expression on keratinocytes induced by IFN gamma. These results suggest that endogenously produced SC, as well as exogenously added FSC, acts as an inhibitor of IFN gamma. Therefore, our results suggest that SC plays an antiinflammatory role in the pathogenesis of inflammatory skin diseases via inhibition in keratinocytes of IFN gamma induced expression of ICAM-1 and HLA-DR.

Cells, Cultured↗

PubMed1995

A study of cytokines in burn blister fluid related to wound healing.

This report indicates that retention fluid from blisters of partial skin thickness burns, which contains relatively large amounts of cytokines and growth factors, stimulates the wound healing process. Although epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) levels were low, relatively large amounts of cytokines including platelet derived growth factor (PDGF), interleukin (IL-6) and transforming growth factor (TGF) alpha were present and these exercised stimulatory effects on wound healing. TGF beta, which plays an important role in collagen metabolism and in scar formation, was also detected. Contrary to our expectations, IL-1 alpha and beta, both of which initiate inflammation, were detected at relatively low levels whereas IL-8 levels were rather high. Various cytokines were shown to coexist in a balanced state in the retention fluids, suggesting that epithelialization might be regulated via a cytokine network operating on the wound surface. The growth of keratinocytes in culture significantly increased with the addition of 1 per cent or more of blister fluid to the medium.

Blister↗

PubMed1994

Electrochemical therapy for intermediate and advanced liver cancer: a report of 50 cases.

Fifty cases of primary liver cancer were treated by electrochemical therapy (ECT). Tumour size ranged from 3.5 to 21.0 cm. ECT was performed by administration of 6-10 V, 50-100 mA and an electric quantity of 300-1000 C. Duration of treatment was one and a half to four hours. There was an inverse relationship between tumour size and curative effect. There was no death within three months of treatment. Six- and 12-month survival was 88% and 69%, respectively. In conclusion, ECT is an effective treatment which prolongs the patients' life. We have found the method to be of practical value in the management of liver cancers in the intermediate or advanced stage.

Adult↗

PubMed1992

Identification of B beta chain domains involved in human fibrinogen assembly.

Fibrinogen chains are assembled in a stepwise manner in the rough endoplasmic reticulum prior to secretion of the final six-chain dimeric molecule. Previous studies indicated that the synthesis of B beta may be a rate-limiting factor in the assembly of human fibrinogen. To determine the domains of B beta which interact with the other two component chains of fibrinogen, deletion mutants of B beta were transiently co-expressed, together with A alpha and gamma chains, in COS cells, and fibrinogen assembly and secretion were measured. Deletion of the COOH-terminal half of the B beta chain (amino acids 208-461) did not affect assembly and secretion. Assembly of A alpha, gamma, and B beta also occurred when the first NH2-terminal 72 amino acids of B beta were deleted, but not when 93 amino acids were deleted. This indicates that the B beta domain between amino acids 73 and 93 is necessary for the assembly of the three fibrinogen chains. This domain marks the start of the alpha-helical "coiled-coil" region of fibrinogen.

Amino Acid Sequence↗

PubMed1992

Effect of total percent polyacrylamide in capillary gel electrophoresis for DNA sequencing of short fragments. A phenomenological model.

Polyacrylamide capillary gels were prepared with constant (5% C) cross-linker concentration and with total acrylamide concentration ranging from 2.5 to 6% T. At each acrylamide concentration, peak spacing was constant for DNA sequencing fragments ranging from 25 to 250 nucleotides in length. Peak spacing increased linearly with the total acrylamide concentration. The intercept of the retention time vs. fragment length plot was independent of % T. Ferguson plots were constructed for short DNA fragments; the polyacrylamide pore size falls in the 2.5 to 3.5 nm range for the gels studied. Theoretical plate count is independent of total acrylamide concentration; longitudinal diffusion, and not thermal gradients, limit the plate count. A phenomenological model is presented that predicts retention time, plate count, and resolution for sequencing fragments ranging in size from 25 to 250 bases and gels that range from 2.5 to 6% total acrylamide.

Acrylic Resins↗

PubMed1992

Attachment of a single fluorescent label to peptides for determination by capillary zone electrophoresis.

Complicated electropherograms are produced in the separation of fluorescently labeled peptides. Incomplete labeling of epsilon-amino groups on lysine residues results in the production of 2n-1 reaction products, where n is the number of alpha and epsilon amino groups in the peptide. A single label is attached to the peptide by first taking the peptide through one cycle of the Edman degradation reaction. All epsilon-amino groups are converted to the phenyl thiocarbamyl and the cleavage step exposes one alpha-amino group at the N-terminus of the peptide; the fluorescent label is attached to the N-terminus.

Amino Acid Sequence↗

PubMed1992

[Island flap with anastomosis of small saphenous vein to great saphenous vein].

We have devised a small saphenous island flap and successfully used in 6 patients for repairing soft tissue defect of the hell and the sole. After its transference, the small saphenous vein was anastomosed to the large saphenous vein over the ankle in order to obtain the blood supply from the small saphenous vein and blood return through the large saphenous vein. The advantage of this flap is that the vessels are superficial with large caliber so that it is easy to do anastomosis without any influence to the donor area. We believe that this flap can be used to repair soft tissue defect of the leg and foot. In this article, the operative method and advantages and shortcoming are introduced.

Adult↗

PubMed1992

[Combined gu chi wan and spiramycin in the treatment of periodontal disease].

The purpose of the present study is to evaluate clinical effect of the integrated traditional Chinese and western medicine in the treatment of periodontal disease. 90 patients suffered from mild to advanced periodontitis were divided into two groups. The gu chi wan (tooth firming pills) group was administered tooth firming pills 4 mg twice daily for 3-6 months combined with spiramycin 0.2 four times daily for 5 days and routine periodontal treatment. The spiramycin group, as control, was administered spiramycin 0.2 four times daily for 5 days combined with routine periodontal treatment. The clinical parameters: GI, PLI, PDI and serial radiographs were checked on the beginning of study and through 3, 6, 12, 24 months follow up study. The results showed that the GI and PDI of the gu chi wan group decreased significantly than the control group (P less than 0.001). The inflammatory recurrence rate was 33% in the control group and 12% in gu chi wan group and the serial radiographs demonstrated that a higher incidence of bone fill occurred in gu chi wan group than in the control group (P less than 0.01).

Adolescent↗

PubMed1992

[Clinico pathologic analysis of 1503 thyroid tumors].

A clinicopathologic analysis of 1503 thyroid tumors was conducted revealing 82.9% of benign and 17.8% of malignant lesions. The most common type of benign tumor was simple adenoma (62.1%) and of malignant tumor, papillary adenocarcinoma (52.5%). The malignant to benign tumor ratio was 1:4.8. The male to female sex ratio was 1:2.6 in the malignant and 1:3.8 in the benign tumors. The overall 5- and 10-year survival rates for all cancers were 67.7% and 47.6%, respectively. It is suggested that the follicular carcinoma could further be divided into well differentiated (papillary and follicular), poorly differentiated (including squamous cell carcinoma) and undifferentiated types.

Adenocarcinoma↗

PubMed1991

Three DNA sequencing methods using capillary gel electrophoresis and laser-induced fluorescence.

Capillary gel electrophoresis is demonstrated for the four-spectral-channel sequencing technique of Smith, the two-spectral-channel sequencing technique of Prober, and the one-spectral-channel sequencing technique of Richardson and Tabor. Sequencing rates up to 1000 bases/h are obtained at electric field strengths of 465 V/cm. At lower electric field strengths, capillary electrophoresis produces useful data for fragments greater than 550 nucleotides in length with 2 times better resolution than slab gel electrophoresis. An on-column detector produces detection limits of 200 zmol (1 zmol = 10(-21) mol = 600 molecules) for the four-spectral-channel technique. A postcolumn detector, based on the sheath flow cuvette, produces detection limits of 20 and 2 zmol for the two- and one-spectral-channel techniques, respectively.

Base Sequence↗

PubMed1991

Low-cost, high-sensitivity laser-induced fluorescence detection for DNA sequencing by capillary gel electrophoresis.

A low cost, 0.75-mW helium neon laser, operating in the green region at 534.5 nm, is used to excite fluorescence from tetramethylrhodamine isothiocyanate-labelled DNA fragments that have been separated by capillary gel electrophoresis. The detection limit (3 sigma) for the dye is 500 ymol [1 yoctomole (1 ymol) = 10(-24) mol] or 300 analyte molecules in capillary zone electrophoresis; the detection limit for labeled primer separated by capillary gel electrophoresis is 2 zmol [1 zeptomole (1 zmol) = 10(-21) mol]. The Richardson-Tabor peak-height encoded sequencing technique is used to prepare DNA sequencing samples. In 6% T, 5% C acrylamide, 7 M urea gels, sequencing rates of 300 bases/hour are produced at an electric field strength of 200 V/cm; unfortunately, the data are plagued by compressions. These compressions are eliminated with addition of 20% formamide to the sequencing gel; the gel runs slowly and sequencing data are generated at a rate of about 70 bases/hour.

Base Sequence↗

PubMed1991

Mechanistically significant diastereoselection in the sulfoximine inhibition of carboxypeptidase A.

The diastereomers of L-alpha-[ [S-(2-phenylethyl)sulfonimidoyl]methyl]benzenepropanoic acid bind differentially to carboxypeptidase A. These putative transition state-analogue inhibitors show unique and interpretationally significant pH dependences for Ki, as well as for the visible absorption spectra of their E.I complexes in the case of the cobalt-substituted enzyme. From the geometry of the enzymically preferred isomer, it may be concluded that the mechanism of peptide scission by the enzyme entails addition of a nucleophile to the si face of the bound-substrate prochiral carboxamide linkage. New interpretational constraints on the mode of action of the enzyme are thereby imposed.

Binding Sites↗

PubMed1991

Immunocompetence and oxidant defense during ascorbate depletion of healthy men.

To determine nonscorbutic effects of moderate vitamin C deficiency we measured immune function and oxidative damage in eight healthy men (25-43 y) who consumed 5-250 mg/d of ascorbic acid over 92 d on a metabolic unit. During ascorbic acid intakes of 5, 10, or 20 mg/d, subjects attained a state of moderate ascorbic acid deficiency as ascorbic acid concentrations in plasma, leucocytes, semen, and buccal cells dropped to less than 50% of baseline with no scorbutic symptoms observed. No changes in cell proliferation, erythrocyte antioxidant enzymes, and DNA strand breaks were observed; however, blood levels of glutathione and NAD(P) decreased during ascorbic acid deficiency, as did delayed hypersensitivity responsiveness. Concentrations of the oxidatively modified DNA base, 8-hydroxydeoxyguanosine in sperm DNA and fecapentaenes, ubiquitous fecal mutagens, were increased during ascorbic acid depletion. Moderate vitamin C deficiency, in the absence of scurvy, results in alteration of antioxidant chemistries and may permit increased oxidative damage.

Adult↗

PubMed1991

Glutathione blood levels and other oxidant defense indices in men fed diets low in vitamin C.

Because ascorbic acid is an important contributor to the oxidant defense system in body tissues, we studied the effects of a low dietary intake of ascorbic acid on various indicators of oxidant defense and oxidant damage. During a 13-wk study eight healthy men (25-43 y), residing in a live-in metabolic unit, were fed controlled diets containing different amounts of ascorbic acid for four consecutive periods: period 1 = 250 mg/d for 4 d; period 2 = 5 mg/d for 32 d; period 3 = 10 or 20 mg/d for 28 d and period 4 = 60 or 250 mg/d for 28 d. Measurements were made at several time intervals of the activities of glutathione peroxidase and superoxide dismutase in RBC, DNA strand breaks in mononuclear leucocytes, glutathione concentrations in plasma and RBC and NAD and NADP in RBC. After 60 d of low ascorbic acid intakes and associated with plasma ascorbic acid levels less than 6 mumol/L, the total glutathione concentration and the reduced glutathione:oxidized glutathione ratio were decreased in plasma. At the same time NAD and NADP levels in RBC were elevated. It seems that chronic marginal vitamin C deficiency states may be associated with selected biochemical changes in oxidant defense indices.

Adult↗

PubMed1991

Bacteriological study of juvenile periodontitis in China.

The predominant cultivable bacteria associated with juvenile periodontitis (JP) in China were studied for the first time. Subgingival plaque samples were taken on paper points from 23 diseased sites in 15 JP patients and from 7 healthy sites in 7 control subjects. Serially diluted plaque samples were plated on nonselective blood agar and on MGB agar, a selective medium for the isolation of Actinobacillus actinomycetemcomitans. Fifteen or more isolated colonies from each sample (in sequence without selection) were purified for identification. The results indicated that the microflora in healthy sulci of the 7 control subjects was significantly different from that in diseased sites of JP patients. The predominant species in healthy sulci were Streptococcus spp. and Capnocytophaga gingivalis. In JP patients, Eubacterium sp. was found in significantly higher frequency and proportion. Actinobacillus actinomycetemcomitans was not detected in any samples. It appears that this species is not associated with juvenile periodontitis in China.

Actinobacillus↗

PubMed1991

[Clinical analysis and epidemiological investigation of proteinoid corneal degeneration].

A series of corneal degeneration similar to Labrador keratopathy occurring in the Mongol nationalities is reported. Epidemiological survey indicated the incidence to be 8.11%, mostly among people over 30 years, and to increase with age. The majority of cases were bilateral and asymptomatic, showing proteinoid guttate opacities in the superficial layers and lower quadrants of the cornea. The etiology was believed to be related to altitude, cold windy and dusty environment, and probably alcohol.

Adult↗

PubMed1991

Cepholosporium acremonium. A new strain of fungus causing white piedra.

A strain of fungus (CZ408) was isolated from white piedra of a female child. Mycological identification showed that it is the first case in the world. Asymptomatic white nodules were noted on the hair of the scalp, and they were distributed irregularly along the shaft 4-10 cm from the scalp. The nodules, hard, not easily broken or removed, consist of hyphae, spores and metabolic materials around the hair. Oral antimycotic drugs are effective in treating this disease.

Acremonium↗