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Biomedical subjects

Z Chen

Publications and source records attributed to Z Chen.

At least 541 records · Page 30Linked to original sources
PubMed2000

[Evaluation of the effect of streptomycin perfusion of the labyrinth in the treatment of Meniere's disease and endolymphatic hydrops].

OBJECTIVE: To investigate the clinical effect of streptomycin perfusion of the labyrinth (SPL) in the treatment of Meniere's disease. METHOD: 13 patients with Meniere's disease and 3 patients with delayed endolymphatic hydrops (DEH) underwent SPL. The follow-up time was between 5 and 7 years (average 6.3 years). RESULT: Vertigo was completely controlled in 9 patients, substantialy controlled in 4, limitedly controlled in 2 and not controlled in 1. Hearing was improved in 1 patients, stabilized in 5 and worse in 10. Tinnitus was improved in 3 patients, stabilized in 5 and worse in 8. CONCLUSION: SPL is a safe and effective method in the treatment of Meniere's disease and DEH, but the hearing may be insulted and tinnitus may be worse in some patients.

Adult↗
PubMed2000

[Effect of natrahagin, a Chinese cobra venom proteinase on hemorrheology in rat].

The effects of natrahagin, a Chinese cobra venom proteinase on hemorrheology and plasma fibrinogen level in rat was investigated. The results showed that intravenous injection of natrahagin (0.025-0.1 mg/kg) dose-dependently decreased the whole blood viscosity and the plasma viscosity (P < 0.05 or P < 0.01) in rat, but caused no significant effect on hematocrit (P > 0.05). Natrahagin also decreased the plasma fibrinogen level (P < 0.05 or P < 0.01) of rat in a dose-dependent manner at these doses.

Animals↗
PubMed2000

[Morphological and commercial identification on semen torreyae].

The morphological characters and commercial identification on Semen Torreyae has been reported. The results of identification of commercial samples indicated that Torreya grandis was mainly used; T. fargesii, T. yunnanensis and T. jackii were used in their producing areas.

Pharmacognosy↗
PubMed2000

[Determination of amino acids in seeds of genus Torreya in China].

OBJECTIVE: To determine the contents and analyze the ingredients of the amino acids in seeds of genus Torreya. METHODS: The amino acid contents and ingredients were determined by amino acid analyzer. RESULTS: There were 19 amino acids in the seeds of T. grandis, T. grandis cv. merrillii, T. yunnanensis, T. jackii and T. fargesii, and their amino acid contents are 9.10%, 9.90%, 5.03%, 7.26% and 6.07% respectively. There were 17 amino acids in the seeds of T. jiulongshanensis, T. nucifera and T. grandis cv. merrillii (baked) and their amino acid contents are 14.11%, 9.87% and 9.22% respectively. tively.

Amino Acids↗
PubMed2000

[The identification of Bungarus multicinctus multicinctus and its confused species by SDS-PAGE].

The comparative study of the proteins of Bungarus multicinctus multicinctus and Natrix annularis was carried out by SDS-PAGE. The results showed that there were significant differences between their SDS-PAGE figures. On the basis of the study the molecular weights of their characteristic proteins were determined. The results could be regarded as a reference for identification of Bungarus multicinctus multicinctus and its confused species.

Animals↗
PubMed2000

[The preventive effect of the oil from the seed of Torreya grandis cv. merrillii on experimental atherosclerosis in rats].

OBJECTIVE: To determine the preventive effect of the oil from the seed of Torreya grandis cv. merrillii (OTM) on experimental atherosclerosis in rats. METHODS: The concentration of blood lipids, plasma thromboxane (TXA2), prostacyclin (PGI2), the ratio of TXA2/PGI2 and endothelin (ET) were investigated in male Wistar rats fed high-fat feed (HFF) containing OTM(2%) for 12 weeks. RESULTS: OTM could reduce the level of serum total cholesterol (TC), triglyceride (TG) and the atherosclerosic index (AI), and increase the level of serum high-density-lipoprotein cholesterol (HDL-C). The plasma concentration of TXA2, ET and the ratio of TXA2/PGI2 in group supplemented with OTM were lower than those in HFF group. Moreover, the level of plasma PGI2, was higher than that in HFF group. CONCLUSION: OTM is beneficial in preventing atherosclerosis.

Animals↗
PubMed2000

[The hereditary liability of otosclerosis and the strategies for treatment and prevention].

OBJECTIVE: Otosclerosis is a disease of hereditary liability. It might be related to an autosomal dominant inheritance. The genetic penetrance is determined by multifactorial influences. This paper was designed to study the reasonable strategies for prevention and treatment of this disease. METHODS: A retrospective review derived from data of the management and follow-up of 14 cases in 6 families. According to the special pathological features of active phase of the otospongiosis, the suitable strategies for prevention and treatment of this disease were suggested. RESULTS: Diagnosis of 14 cases were confirmed by audiological, operative and/or pathological examinations. Eleven of fourteen cases underwent stapedectomy, in which 10 cases had the surgery on the ear with severer hearing loss, and one case on both sides. In all of the surgical cases, hearing levels improved significantly. Three cases have not yet received the stapedectomy, in which two cases scheduled for the surgery are currently treated by chondroitin sulfate and one case refused the surgical treatment due to financial shortage. CONCLUSION: Examination of the ear function at regular intervals (6-12 months) is recommended for the adults among the family members with high-incidence of otosclerosis. Audiological and radiological examination play an important role in early diagnosis and treatment. Attention should be paid to the medicine for management and prevention of this disease. Stapedectomy is an optimal choice for clinical otosclerosis not only due to its capacity to improve the hearing level but also to prevent the advance of hearing loss. Hearing aid is the suitable choice if stapedectomy is contraindicated.

Audiometry↗
PubMed2000

[Precise map of allelic loss on chromosome 3p14 in nasopharyngeal carcinoma].

OBJECTIVE: To determine the precise allelic loss on chromosome 3p14 and discuss the possible relations between loss of heterozygosity (LOH) and EBV infection, clinical stage and clinic-pathology of nasopharyngeal carcinoma (NPC). METHODS: Six high dense microsatellite marker on chromosome 3p14 were selected to examine LOH in 32 cases of NPC. RESULTS: 23 of 32 (71.9%) tumors were deleted for at least one locus of six loci. High frequencies of LOH (> 40%) were observed at loci D3S1300(50.0%), D3S1313(46.4%) and D3S1312(44.4%). 12 cases showed LOH in one contiguous and nonrandom region. The smallest common deletion region seems likely to lie between D3S1313 and D3S1312. Relations between LOH on 3p14 and clinical stage and EBV infection were observed. The frequency of LOH was 70.0% in 30 cases of poor-differentiated squamous cell carcinoma. 2 cases of vesicular nucleus cell carcinoma had LOH at two loci. CONCLUSION: The high deletion rate on 3p14 in NPC indicates that there might be a putative tumor suppressor gene related to the development and progression of NPC.

Alleles↗
PubMed2000

Protection against leptospirosis by immunization with plasmid DNA encoding 33 kDa endoflagellin of L. interrogans serovar lai.

OBJECTIVE: To evaluate how the efficacy of DNA inocutation affects the ability to raise protective immunity against Leptospira. METHODS: A pair of oligonucleotide primers were designed to amplify the endoflagellar gene of L. interrogans sensu stricto serovar lai. An approximately 840bp fragment was generated with PCR and inserted into VR1012, a plasmid DNA expression vector, after the fragment and VR1012 were digested respectively with EcoRV and Sal I. A recombinant plasmid designated as VR1012+flaB2 was obtained. The vector, VR1012 consits of a pUC18 backbone with the cytomegalovirus (CMV) IE1 enhancer, promoter, and intron A, transcription regulatory elements and the BGH polyadenylation sequences driving the expressing of leptospiral endoflagellar gene of L. interrogans sensu stricto serovar lui. Plasmid encoding leptospiral endoflagellin gene was injected into quadriceps of NZW rabbits. RESULTS: This resulted in the generation of specific leptospiral antibody with high ELISA titer (1:32768) in the rabbits. Immuno/protection was performed in guinea pigs without adjuvant. The group "VR1012 + flaB2" showed higher survival rate (90%, 9/10 animals), compared with the group "VR1012 lack flaB2" and the group "normal saline". CONCLUSION: The technique of DNA vaccine has potential advantages over certain other vaccine preparation technologies. However whether DNA vaccine will be useful for vaccine development remains to be tested.

Animals↗
PubMed2000

[Study on the IR and UV dual-spectrum radiation].

The article gives a method to produce dual spectrum radiation in IR and UV. Relying on theoretical analysis, the relative data are computed, some atomic materials are selected and added to a double-base propellants. When the UV pyrotechnics is ignited together with traditional IR pyrotechnics, the spectrum of IR and UV is emitted at the same time. The final measuring curves show that all results are satisfying.

English Abstract↗
PubMed1999

Modulation of Ca(2+) entry by polypeptides of the inositol 1,4, 5-trisphosphate receptor (IP3R) that bind transient receptor potential (TRP): evidence for roles of TRP and IP3R in store depletion-activated Ca(2+) entry.

Homologues of Drosophilia transient receptor potential (TRP) have been proposed to be unitary subunits of plasma membrane ion channels that are activated as a consequence of active or passive depletion of Ca(2+) stores. In agreement with this hypothesis, cells expressing TRPs display novel Ca(2+)-permeable cation channels that can be activated by the inositol 1,4,5-trisphosphate receptor (IP3R) protein. Expression of TRPs alters cells in many ways, including up-regulation of IP3Rs not coded for by TRP genes, and proof that TRP forms channels of these and other cells is still missing. Here, we document physical interaction of TRP and IP3R by coimmunoprecipitation and glutathione S-transferase-pulldown experiments and identify two regions of IP3R, F2q and F2g, that interact with one region of TRP, C7. These interacting regions were expressed in cells with an unmodified complement of TRPs and IP3Rs to study their effect on agonist- as well as store depletion-induced Ca(2+) entry and to test for a role of their respective binding partners in Ca(2+) entry. C7 and an F2q-containing fragment of IP3R decreased both forms of Ca(2+) entry. In contrast, F2g enhanced the two forms of Ca(2+) entry. We conclude that store depletion-activated Ca(2+) entry occurs through channels that have TRPs as one of their normal structural components, and that these channels are directly activated by IP3Rs. IP3Rs, therefore, have the dual role of releasing Ca(2+) from stores and activating Ca(2+) influx in response to either increasing IP3 or decreasing luminal Ca(2+).

Amino Acid Sequence↗
PubMed1999

Molecular cloning of six novel Krüppel-like zinc finger genes from hematopoietic cells and identification of a novel transregulatory domain KRNB.

To clone zinc finger genes expressed in hematopoietic system, we designed primers based on conserved Cys(2)/His(2) zinc finger sequences to amplify corresponding domains from mRNA of normal bone marrow and leukemia cell line NB4. DNA fragments of novel zinc finger genes were chosen and used as probe pool to screen cDNA libraries or subject to rapid amplification of cDNA ends in order to obtain full-length cDNA. Six cDNAs including whole open reading frame of zinc finger proteins, named as ZNF191, ZNF253 (BMZF-1), ZNF255 (BMZF-2), ZNF256 (BMZF-3), ZNF257 (BMZF-4), and ZNF254 (BMZF-5) were obtained. All six belong to the Krüppel-like zinc finger gene family, and typical transcriptional regulatory motifs exist in the N-terminal moiety, such as the SCAN box in ZNF191, and the KRAB domains in ZNF253, ZNF254, ZNF256, and ZNF257. A previously undefined sequence nominated as Krüppel-related novel box, which may represent a new transregulatory motif, was revealed at the N terminus of ZNF255. The transregulatory function of non-zinc finger regions of ZNF191, ZNF253, and ZNF255 were addressed in yeast and mammalian cells. The results indicated that ZNF255 might be a conditional transactivator, whereas ZNF253 and ZNF191 displayed a suppressive effect on the transcription in yeast and/or mammalian systems.

Amino Acid Sequence↗
PubMed1999

The refined crystal structure of cowpea mosaic virus at 2.8 A resolution.

Comoviruses are a group of plant viruses in the picornavirus superfamily. The type member of comoviruses, cowpea mosaic virus (CPMV), was crystallized in the cubic space group I23, a = 317 A and the hexagonal space group P6(1)22, a = 451 A, c = 1038 A. Structures of three closely similar nucleoprotein particles were determined in the cubic form. The roughly 300-A capsid was similar to the picornavirus capsid displaying a pseudo T = 3 (P = 3) surface lattice. The three beta-sandwich domains adopt two orientations, one with the long axis radial and the other two with the long axes tangential in reference to the capsid sphere. T = 3 viruses display one or the other of these two orientations. The CPMV capsid was permeable to cesium ions, leading to a disturbance of the beta-annulus inside a channel-like structure, suggesting an ion channel. The hexagonal crystal form diffracted X rays to 3 A resolution, despite the large unit cell. The large ( approximately 200 A) solvent channels in the lattice allow exchange of CPMV cognate Fab fragments. As an initial step in the structure determination of the CPMV/Fab complex, the P6(1)22 crystal structure was solved by molecular replacement with the CPMV model determined in the cubic cell.

Amino Acid Sequence↗
PubMed1999

Ezrin, a membrane-cytoskeletal linking protein, is involved in the process of invasion of endometrial cancer cells.

In order to study ezrin function in tumor growth and invasion, we used two cell lines of human endometrial cancers. Ishikawa, the low-metastatic endometrial cancer cell line, and its subclone (mEIIL) with high-metastatic activity and higher ezrin expression were treated with a ezrin antisense phosphorothioate oligonucleotides (ePONs) pulse four times before the in vitro growth assay and Matrigel invasion assay. ePONs significantly suppressed the number of both cells that penetrated through Matrigel membrane (inhibition rate; 40.1 +/- 7.5% (Ishikawa), 42.7 +/- 2.4% (mEIIL), mean +/- SD, n = 6, P < 0.05, Student's t-test), whereas they showed no effect on cell proliferation. Ezrin expression at the protein level was inhibited by ePONs. These data suggest that ezrin expression is required for invasion. The association of high ezrin expression in mEIIL and its higher ability to migrate through Matrigel may at least in part indicate functional significance of ezrin in endometrial cancer metastasis.

Adenocarcinoma↗
PubMed1999

Human signal-regulatory protein is expressed on normal, but not on subsets of leukemic myeloid cells and mediates cellular adhesion involving its counterreceptor CD47.

Signal-regulatory proteins (SIRPs) comprise a novel transmembrane glycoprotein family involved in the negative regulation of receptor tyrosine kinase-coupled signaling pathways. To analyze the expression and function of SIRPs, we prepared soluble recombinant fusion proteins of the extracellular regions of SIRPalpha1 and SIRPalpha2, as well as a variety of monoclonal antibodies (MoAbs) against these domains. The antibodies reacted predominantly with monocytes, granulocytes, dendritic cells, and their precursors, as well as with bone marrow CD34(+), AC133(+), CD90(+) hematopoietic stem/progenitor cells. In contrast, SIRP expression was absent or significantly reduced on the majority of myeloid blasts from patients with acute myeloid leukemia (AML) or chronic myeloid leukemia (CML). Functional studies showed that the extracellular domains of SIRPalpha1 and SIRPalpha2 support adhesion of a number of primary hematopoietic cells and cell lines. This interaction could be blocked by 4 of 7 SIRPalpha1-reactive MoAbs. In addition, SIRPalpha1 and SIRPalpha2 competed for the same cell binding site, suggesting a common widely expressed SIRP ligand. In an approach to identify this molecule, MoAbs were generated against the SIRP-binding cell line CCRF-CEM, and MoAb CC2C6 was selected because of its capacity to inhibit cell binding to SIRPalpha1. Further analysis showed that this antibody recognized CD47, a ubiquitously expressed plasma membrane protein previously implicated in integrin function, host defense action, and neutrophil migration. In this study, we identify CD47 as the extracellular ligand for human SIRP and show that these two counterreceptors are involved in cellular adhesion.

Antigens, CD↗
PubMed1999

The earliest angiosperms: evidence from mitochondrial, plastid and nuclear genomes.

Angiosperms have dominated the Earth's vegetation since the mid-Cretaceous (90 million years ago), providing much of our food, fibre, medicine and timber, yet their origin and early evolution have remained enigmatic for over a century. One part of the enigma lies in the difficulty of identifying the earliest angiosperms; the other involves the uncertainty regarding the sister group of angiosperms among extant and fossil gymnosperms. Here we report a phylogenetic analysis of DNA sequences of five mitochondrial, plastid and nuclear genes (total aligned length 8,733 base pairs), from all basal angiosperm and gymnosperm lineages (105 species, 103 genera and 63 families). Our study demonstrates that Amborella, Nymphaeales and Illiciales-Trimeniaceae-Austrobaileya represent the first stage of angiosperm evolution, with Amborella being sister to all other angiosperms. We also show that Gnetales are related to the conifers and are not sister to the angiosperms, thus refuting the Anthophyte Hypothesis. These results have far-reaching implications for our understanding of diversification, adaptation, genome evolution and development of the angiosperms.

Biological Evolution↗