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Biomedical subjects

H Zeng

Publications and source records attributed to H Zeng.

At least 91 records · Page 5Linked to original sources
PubMed2000

[Response to milrinone treatment in patients with chronic congestive heart failure].

The objective of this study was to examine the efficacy of milrinone in chronic congestive heart failure. In this randomized, double-blind, placebo-controlled trial, 30 patients with class III or IV chronic congestive heart failure were randomly assigned to receive milrinone (n = 15) or placebo (n = 15). The results showed that in the milrinone group, stroke volume increased from 38.50 +/- 5.34 to 64.93 +/- 6.46 ml (P < 0.001), cardiac output increased from 3.39 +/- 0.42 to 5.28 +/- 0.55 L/min (P < 0.001), cardiac index increased from 2.01 +/- 0.42 to 3.21 +/- 0.57/min/m2 (P < 0.001) and ejection fraction increased from 0.23 +/- 0.05 to 0.35 +/- 0.06(P < 0.001). In the placebo group, no hemodynamic effects were found. Milrinone favourably influenced the symptoms and heart function in 11/15(73.3%) patients. In the placebo group, only 4/15(26.7%) patients had such response (P < 0.05). These data indicate that milrinone is effective for improving the hemodynamics status and heart function in patients with chronic heart failure.

Adolescent↗
PubMed2000

[Studies on chemical components of the volatile oil from the leaves of Hypericum perforatum].

OBJECTIVE: To determine the volatile oil of the leaves from Hypericum perforatum L.. METHOD: The essential oil was obtained by simultaneous distillation and solvent extraction. The chemical components were seperated and identified by GC-MS. The relative contents in the volatile oil were determined by area nomalization. RESULTS: 54 chemical constituents were separated and identified representing 92.32% of the total contents. CONCLUSION: Sesquiterpenes are major chemical constituents in the oil from the leaves of Hypericum perforatum L.. They are very different from those of the essential oil from the same species from the other country.

Gas Chromatography-Mass Spectrometry↗
PubMed2000

[Infrared spectra and Raman spectra of monoclinic RblnS2 and CsInS2].

Monoclinic RbInS2 and CsInS2 were prepared by the traditional flux method and their IR and Raman spectra were studied. The IR and Raman absorption bands of CsInS2 shift to lower frequency compared with RbInS2. IR and Raman spectra show that monoclinic RbInS2 and CsInS2 exhibit good infrared transmission.

English Abstract↗
PubMed1999

Expression of multidrug resistance protein-3 (multispecific organic anion transporter-D) in human embryonic kidney 293 cells confers resistance to anticancer agents.

Multidrug resistance-associated protein (MRP)1 and canalicular multispecific organic anion transporter (cMOAT)/MRP2 are ATP-binding cassette (ABC) transporters that confer resistance to natural product cytotoxic drugs. We recently described the complete coding sequences of four human MRP/cMOAT subfamily members and found that, among these proteins, MRP3/MOAT-D is most closely related to MRP1 (58% identity; M. G. Belinsky and G. D. Kruh, Br. J. Cancer, 80: 1342-1349, 1999). In the present study, we sought to determine whether MRP3 is capable of conferring resistance to cytotoxic drugs. To address this question, human embryonic kidney 293 cells were transfected with an MRP3 expression vector, and the drug resistance phenotype of the transfected cells was analyzed. The MRP3-transfected cells displayed approximately 4-fold resistance to etoposide and approximately 2-fold resistance to vincristine, compared with control transfected cells. In addition, approximately 1.7-fold resistance was observed for the antimetabolite methotrexate. Increased resistance was not observed for several other natural product agents, including anthracyclines and Taxol. The MRP-transfected cells exhibited reduced accumulation of radiolabeled etoposide, consistent with the operation of a plasma membrane efflux pump. These results indicate that MRP3 confers resistance to some anticancer agents but that its resistance pattern is distinct from the resistance patterns of other ABC transporters involved in resistance to natural product chemotherapeutic agents.

ATP-Binding Cassette Transporters↗
PubMed1999

A Supramolecular Tetra-Keggin Polyoxometalate

Giant polyoxometalates with catalytic, magnetic, and antiviral properties, which are in part attributable to their structures, are currently of great interest. Herein is described the synthesis and characterization of 1, a structurally novel tetrameric complex from Keggin ions (see picture). This complex is stable under the physiological conditions of the stomach (pH 1-2), which is interesting since related keggin anions are among the least toxic and yet most potent antiviral agents of the more than 300 polyoxometalates investigated biologically and pharmacologically.

Journal Article↗
PubMed1999

New method for detection of heart allograft rejection: validation of sensitivity and reliability in a rat heterotopic allograft model.

BACKGROUND: Patients with inflammatory heart muscle diseases would benefit from a safe, convenient, rapidly performed diagnostic technique with real-time results not involving tissue removal. We have performed a detailed evaluation of detection of heart allograft rejection by autofluorescence in a heterotopic abdominal rat heart allograft model ex vivo. METHODS AND RESULTS: Recipient rats with allograft (Lewis to Fisher 344; n=71) and isograft (Lewis to Lewis; n=33) hearts, treated with cyclosporine or untreated, were killed at days 2, 4, 7, 14, 21, 28, and 56 after transplant. Nontransplant controls with (n=24) or without (n=24) immunosuppressive therapy were also studied. When the rats were killed, autofluorescence spectra were acquired under blue-light excitation from midtransverse ventricular sections of native and transplanted hearts. Corresponding sections were then evaluated pathologically by a modified International Society for Heart and Lung Transplantation (ISHLT) grading schema. The spectral differences between rejecting and nonrejecting hearts were quantified by linear discriminant functions, producing scores that decreased progressively with increasing severity of tissue rejection. Mean+/-SD discriminant function scores were 2.9+/-1.6, 1.8+/-2.2, -0.1+/-2.8, -1.2+/-2.3, and -2.3+/-3.0 for isografts and allograft ISHLT grades 0, I, II, and III, respectively (Spearman rank-order correlation -0.6; P<0.001, test for trend). Cyclosporine had no detectable effect on the spectra. CONCLUSIONS: The correlation between changes in autofluorescence spectra and ISHLT rejection grade strongly supports the possibility of catheter-based, fluorescence-guided surveillance of rejection.

Animals↗
PubMed1999

Stimulation with carbachol alters endomembrane distribution and plasma membrane expression of intracellular proteins in lacrimal acinar cells.

The events that lead to Sjögren's autoimmune processes in the lacrimal gland remain poorly understood. The acinar cell's responses to acute cholinergic stimulation include release of secretory products across the apical plasma membrane (apm) and a number of processes related to traffic between endomembrane compartments and the basal-lateral plasma membranes (blm), such as recruitment of Na, K-ATPase, accelerated recycling, and accelerated transcytosis of secretory IgA. We tested the hypothesis that stimulation-induced acceleration of endomembrane traffic is accompanied by changes in compartmentation and increased blm expression of proteins that are normally sequestered in endomembrane compartments. Isolated rabbit lacrimal gland acinar cells were cultured in serum-free media for 2 days. After harvesting, cells were incubated with or without 10 microm carbachol at 37 degrees C for 20 min. Cells were lysed, and lysates were analysed by isopycnic centrifugation on sorbitol gradients. Galactosyltransferase catalytic activity was determined biochemically. Different forms of cathepsin B were detected by Western blotting. Carbachol stimulation decreased the contents of beta-hexosaminidase, alpha-glucosidase, and protein in secretory vesicles and increased them in specific compartments of the trans-Golgi network (ld-tgns). Stimulation also caused levels of galactosyltransferase, preprocathepsin B, and procathepsin B to increase two- to three-fold in the blm as well as increasing in the ld-tgns. Other changes caused by sustained stimulation included: (a) increased levels of protein and procathepsin B in compartments of the lysosomal pathway; (b) changes in the distributions of Rab5 within the endomembrane system; (c) changes in the distribution of Rab6 within the Golgi complex and tgn; (d) decreased expression of acid phosphatase and MHC class II molecules in the blm; and (e) decreased total content of Na,K-ATPase, which appeared to have been selectively depleted from the tgn and blmre. We propose that the normal compartmentation of certain proteins may allow them to remain cryptic, such that they are not subject to central tolerance. Stimulation-induced increases in the levels expressed at the blm or secreted to the interstitium may, therefore, contribute to initiation of local autoimmune responses.

Acid Phosphatase↗
PubMed1999

The experimental study on mixed culture of osteoblasts and tricalcium phosphate ceramics in vitro.

To study the effects of tricalcium phosphate (TCP) ceramics on osteoblasts, the rat osteoblasts were cultured with the TCP ceramics in vitro. Scanning electron microscopy and the colorimetric methyl-thiazol-tetrazolium assay showed that the osteoblasts could adhere well to the surface of the ceramics and the culture dish, and the proliferation of the cells was not inhibited. The results demonstrated that TCP ceramics possessed an excellent cytocompatibility with the osteoblasts, and had some promoting effects on proliferation of osteoblasts.

Animals↗
PubMed1999

Analysis of bovine serum albumin adsorption on calcium phosphate and titanium surfaces.

The protein adsorption behavior of thin films of calcium phosphate (CaP) bioceramic and titanium (Ti) was studied in this research. The thin films were produced with an ion beam sputter deposition technique using targets of hydroxyapatite (HA), fluorapatite (FA) and titanium (Ti). Fourier transform infrared spectroscopy (FTIR) with attenuated total internal reflectance (ATR) was used to evaluate protein adsorption on these surfaces. This study showed that surface composition and structure influenced the kinetics of protein adsorption and the structure of adsorbed protein. CaP surfaces adsorbed greater amount of protein than the Ti surface, and caused more alteration of the structure of adsorbed BSA than did the Ti surface. The differences in protein adsorption behavior could result in very different initial cellular behavior on CaP and Ti implant surfaces.

Adsorption↗
PubMed1999

Dissolution/reprecipitation of calcium phosphate thin films produced by ion beam sputter deposition technique.

The dissolution, reprecipitation and protein adsorption properties of amorphous CaP bioceramic thin films produced with an ion beam sputter deposition technique using hydroxyapatite (HA) and fluorapatite (FA) as starting materials were studied using Fourier transform infrared spectroscopy (FTIR) with attenuated total internal reflectance (ATR). Our studies showed that these amorphous CaP coatings dissolved to a greater extent when exposed to bovine serum albumin (BSA) in saline solution when compared to a protein free saline solution. Analysis of changes in infrared spectra revealed that coatings exposed to BSA solution exhibited a higher degree of crystalline structure after dissolution/reprecipitation than those exposed to saline alone. There was the indication that the association of inorganic and organic contents was achieved on the coating surface in BSA solution. We could detect no significant difference between the coatings produced from HA and FA targets.

Adsorption↗
PubMed1999

Effects of quenched disorder on the orientational order of the octylcyanobiphenyl liquid crystal.

Deuteron NMR (DNMR) measurements were performed with high-temperature and spectral resolution on the octylcyanobiphenyl (8CB) liquid crystal confined to the randomly interconnected pores of silica aerogel as a function of temperature and silica density. The aerogel density was varied by one order of magnitude and the temperature spanned the isotropic (I), nematic (N), and smectic-A (SmA) phases of 8CB. For all samples, the liquid crystal was confined to pores smaller than the micron-sized magnetic coherence length. Thus the observed line shapes reflect the director pattern, n(r-->), and the orientational order, Q, as dictated by the porous host. The DNMR spectral patterns are consistent with powder line shapes representative of a randomized n(r-->) characterized by a single Q. The nematic domains formed are of finite dimension that likely exceeds the confining size. The weakly first-order nematic-to-isotropic phase transition becomes less discontinuous with decreasing pore size, eventually becoming continuous at an aerogel density between 0.36 and 0.5 g/cm(3). In the most severe confinement, no phase transitions are observed with only a continuous evolution of Q present. The orientational order is suppressed from the bulk's with no enhancement upon the onset of the SmA phase. This indicates a decoupling of nematic and smectic order parameters and a severe suppression of the SmA phase by this porous media.

Journal Article↗
PubMed1999

Molecular cloning of the Pasteurella haemolytica pomA gene and identification of bovine antibodies against PomA surface domains.

The gene (pomA) encoding PomA, an OmpA-like major outer membrane protein of the bovine respiratory pathogen Pasteurella haemolytica, was cloned, and its nucleotide sequence was determined. The deduced amino acid sequence of PomA has significant identity with the sequences of other OmpA family proteins. Absorption of three different bovine immune sera with whole P. haemolytica cells resulted in a reduction of bovine immunoglobulin G reactivity with recombinant PomA in Western immunoblots, suggesting the presence of antibodies against PomA surface domains.

Amino Acid Sequence↗
PubMed1999

MHC class II molecules, cathepsins, and La/SSB proteins in lacrimal acinar cell endomembranes.

Sjögren's syndrome is a chronic autoimmune disease affecting the lacrimal glands and other epithelia. It has been suggested that acinar cells of the lacrimal glands provoke local autoimmune responses, leading to Sjögren's syndrome when they begin expressing major histocompatibility complex (MHC) class II molecules. We used isopycnic centrifugation and phase partitioning to resolve compartments that participate in traffic between the basolateral membranes and the endomembrane system to test the hypothesis that MHC class II molecules enter compartments that contain potential autoantigens, i.e., La/SSB, and enzymes capable of proteolytically processing autoantigen, i.e., cathepsins B and D. A series of compartments identified as secretory vesicle membranes, prelysosomes, and microdomains of the trans-Golgi network involved in traffic to the basolateral membrane, to the secretory vesicles, and to the prelysosomes were all prominent loci of MHC class II molecules, La/SSB, and cathepsins B and D. These observations support the thesis that lacrimal gland acinar cells that have been induced to express MHC class II molecules function as autoantigen processing and presenting cells.

Acid Phosphatase↗
PubMed1999

Enrichment of transiently transfected mesangial cells by cell sorting after cotransfection with GFP.

Early passage mesangial cells, like many other nonimmortalized cultured cells, can be difficult to transfect. We devised a simple method to improve the efficiency of transient protein expression under the transcriptional control of promoters in conventional plasmid vectors in rat mesangial cells. We used a vector encoding modified green fluorescent protein (GFP) and sterile fluorescence-activated cell sorting (FACS) to select a population consisting of >90% GFP-expressing cells from passaged nonimmortalized cultures transfected at much lower efficiency. Only 10% transfection efficiency was noted with a beta-galactosidase expression vector alone, but cotransfection with GFP followed by FACS and replating of GFP+ cells yielded greater than fivefold enrichment of cells with detectable beta-galactosidase activity. To demonstrate the expression of a properly oriented and processed membrane protein, we cotransfected GFP with a natriuretic peptide clearance receptor (NPR-C) expression vector. Plasmid-dependent cell surface NPR-C density was enhanced by 89% after FACS, though expression remained lower in selected mesangial cells than in the CHO cell line transfected with the same vector. We conclude that cotransfection of rat mesangial cells with GFP, followed by FACS, results in improvement in transient transfection efficiencies to levels that should suffice for many applications.

Adenoviridae↗
PubMed1999

[Influence factors in hepatic artery infusion chemotherapy and embolization of liver metastases from alimentary tract cancer].

OBJECTIVE: To evaluate the efficacy and the value of hepatic artery infusion chemotherapy and embolization in the treatment of liver metastases from alimentary tract cancer with Cox's proportional hazard model. METHODS: A total of 92 patients with unresectable liver metastases from alimentary tract cancer were treated by hepatic artery infusion chemotherapy and embolization in 316 times. Of 92 patients, 29 were given infusion chemotherapy only, 63 were given infusion chemotherapy together with embolization. Anticancer agents were the combination of epirubicin and/or cisplatin, mitomycin-C and fiuorouracil plus calcium folinate, added to embolization with lipiodol ultrafluid or lipiodol ultra-fluid and gelatin sponge. Cox's proportional hazard model was used in multivariate analysis. RESULTS: The results showed that the therapeutic efficacy of 9 cases with single liver metastasis was the best. The mean survival period > 30 months (P < 0.05). Comprehensive treatment significantly improves therapeutic efficacy (P < 0.01). Response rates were assessed by CT scan. An overall response rate (CR + PR) of the cases was 45.65%. The mean survival period of 92 patients were 19.6 months. The 0.5, 1, 2, 3, and 5-year survival rates were 95.7%, 73.8%, 36.3%, 20.6% and 11.6% respectively. These was no severe side effect or complication. CONCLUSION: The hepatic artery infusion chemotherapy and embolization were of benefit to patients with liver metastases from alimentary tract cancer. It contributes not only to improving therapeutic efficacy, but also to an improved quality of life for the patients. Single liver metastasis and comprehensive treatment were the most important influence factors in hepatic artery infusion chemotherapy and embolization of the liver metasetases from alimentary tract cancer.

Adult↗
PubMed1999

[Study on the expression of interleukin-8 and its receptors in acute leukemia].

OBJECTIVE: To evaluate the expression of interleukin 8 (IL-8) and its A, B type receptors (IL-8RA, IL-8RB) in acute leukemia (AL). METHODS: Plasma IL-8 concentrations in peripheral blood and IL-8R expressions on bone marrow mononuclear cell (MNC) membrane of 77 newly diagnosed AL patients were assayed by ELISA and FACS, respectively. IL-8 concentration in cerebral spinal fluid (CSF) of 15 AL patients in complete remission (CR) were kinetically measured. RESULTS: Plasma IL-8 levels in newly diagnosed AL patients were increased. IL-8 levels were higher in AML than in ALL, in AML-M4, M5 were higher than in AML-M1-M3, and in B-ALL were higher than in T-ALL, respectively (P < 0.05). In ALL, CR rate in patients with IL-8 > 100 ng/L was lower than in those with IL-8 < or = 100 ng/L (P < 0.05). 36.36% of the patients were MNC IL-8R positive. Peripheral blood WBC and blasts amounts in IL-8R(+) group were significantly higher than IL-8R (-) group (P < 0.05). CSF IL-8 levels in CR patients were not different from newly diagnosed patients (P > 0.05) and were increased while central nervous system leukemia (CNSL) developed. CONCLUSION: Detection of IL-8 and IL-8R might help to identify AL types and predict prognosis and the development of CNSL.

Adolescent↗