Biomedical subjects

W Fan

Publications and source records attributed to W Fan.

At least 91 records · Page 5Linked to original sources

PubMed1998

[Effect of up-regulation of S-AdoMet synthetase on taxol-induced apoptosis in human breast cancer cells].

OBJECTIVE: To investigate the gene regulation of taxol-induced apoptosis. METHODS: Northern blot hybridization, enzyme activity assay of S-AdoMet synthetase and flow cytometry were performed in the investigation of expression in the mRNA level and biological action of S-AdoMet synthetase in taxol-induced apoptosis in human breast cancer cell line (BCap 37). RESULTS: Up-regulation of S-AdoMet synthetase expression was resulted by taxol treatment and the expression peaked at 48 hours. Moreover, the up-regulation of S-AdoMet synthetase was associated with cytotoxicity of antimicrotubule agents including taxol and colchicine. Inhibition rate of S-AdoMet synthetase activity by 1% DMSO was 34% in taxol-treated cells and 14% in taxol-untreated cells compared to control groups, respectively. Posttreatment with 1% DMSO following pretreatment with individual antitumor agent for 3 hr promoted apoptotic cell death of taxol-, colchicine-, and adriamycin-treated BCap37 cells. CONCLUSION: The induction of apoptosis enhanced by post-treatment with DMSO in taxol-treated cells is probably linked to its inhibition on enzyme activity of S-AdoMet synthetase, suggesting that the increased expression of S-AdoMet synthetase possibly plays an important role in protecting cells from DNA fragmentation in taxol-induced apoptosis.

Antineoplastic Agents, Phytogenic↗

PubMed1998

[Experimental study on reducing effect of shexiang baoxin pill from damage of arterial wall caused by hyperlipemia].

OBJECTIVE: To study the protecting effect of Shexiang Baoxin Pill (SXBXP) on arterial wall in hyperlipemia rabbit model. METHODS: Thirty-six male, New Zealand rabbits were randomized into three groups: control group, fed with common diet for 8 weeks: Hypercholesterolemia group (HC) and SXBXP group (SX), fed with 1% cholesterol and 3% lard diet for 8 weeks. In SX group, SXBXP was iven from 7th week for 2 weeks. The plasma levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were measured at the first, 6th and the 8th week of experiment. Serum superoxide dismutase (SOD) and electrocardiography (ECG) were also evaluated at the 8th week. Light microscopy and transmission electron microscopy were adopted to assess the degree of pathologic damage of arterial wall. RESULTS: SXBXP could reduce the levels of serum TC and LDL-C, as compared with the HC group, P < 0.05. It could also reduce the extent of atherosclerotic lesion and the severity of intimal proliferation. CONCLUSION: SXBXP has the effect of inhibiting development of experimental atherosclerosis.

Animals↗

PubMed1998

[Studies on flavonoids from Fenugreek (Trigonella foenumgraecum L.)].

OBJECTIVE: To study the flavonoids in fenugreek (Trigonella foenumgraecum) produced in China. METHOD: The flavonoids were isolated with silica gel, polyamide and Sephadex LH-20 chromatography, and their structures were identified by physical, chemical properties and spectral analysis. RESULT: Five flavonoid compounds were isolated from fenugreek seeds and identified as vitexin, tricin, naringenin, quercetin and tricin-7-O-beta-D-glucopyranoside. CONCLUSION: Three flavonoids, tricin, naringenin and tricin-7-O-beta-D-glucopyranoside, were isolated from fenugreek as well as from the plants of Trigonella for the first time.

Apigenin↗

PubMed1998

[Chinese Chlorella viruses and their molecular biological properties].

An extensive survey for Chlorella viruses revealed that Chlorella viruses are widely distributed over China. Eleven isolates of Chlorella viruses have been isolated, which lysis the Chlorella viruses sp. (strain NC64A). These isolates were named BJ-1, BJ-2, BJ-3, BJ-4, FJ-1, FJ-2, NJ-1, CDT-1, HCJ-1, SCB-1 and SCC-1 respectively. They have several common properties, including polyhedral morphology, and linear dsDNA genomes. However, the restriction patterns of viral DNA, the concentration of m5dC and m6dA in viral DNA, and the composition of viral structure protein are different among these isolates. All of viral major capsid proteins are 54,000 except FJ-1, whose major capsid protein is smaller than 54,000. Western blot analysis showed strong immunological cross reaction among all of viral proteins with PBCV-1's antiserum except FJ-1. It indicates that the homology between these isolates and PBCV-1 is high. Among these isolates, FJ-1 has some special properties.

Base Composition↗

PubMed1997

Identification of a novel human RAD51 homolog, RAD51B.

The highly conserved Saccharomyces cerevisiae RAD51 protein functions in both mitotic and meiotic homologous recombination and in double-strand break repair. Screening of the public cDNA sequence database for RAD51-like genes led to the identification of a partial sequence from a breast tissue library present in the I.M.A.G.E. (Integrated Molecular Analysis of Genes and their Expression) collection. An extended 1764-bp cDNA clone encoding an open reading frame of 350 amino acids was isolated. This clone showed significant amino acid identity with other human RAD51 homologs. The new homolog, named RAD51B, was mapped to human chromosome 14q23-q24.2 using a panel of human-hamster somatic cell hybrids and fluorescence in situ hybridization. Northern blot analysis demonstrated that RAD51B mRNA is widely expressed and most abundant in tissues active in recombination. Functions associated with known RAD51 homologs suggest a role for RAD51B in meiotic recombination and/or recombinational repair.

Amino Acid Sequence↗

PubMed1997

Cloning, sequencing, gene organization, and localization of the human ribosomal protein RPL23A gene.

The intron-containing gene for human ribosomal protein RPL23A has been cloned, sequenced, and localized. The gene is approximately 4.0 kb in length and contains five exons and four introns. All splice sites exactly match the AG/GT consensus rule. The transcript is about 0.6 kb and is detected in all tissues examined. In adult tissues, the RPL23A transcript is dramatically more abundant in pancreas, skeletal muscle, and heart, while much less abundant in kidney, brain, placenta, lung, and liver. A full-length cDNA clone of 576 nt was identified, and the nucleotide sequence was found to match the exon sequence precisely. The open reading frame encodes a polypeptide of 156 amino acids, which is absolutely conserved with the rat RPL23A protein. In the 5' flanking region of the gene, a canonical TATA sequence and a defined CAAT box were found for the first time in a mammalian ribosomal protein gene. The intron-containing RPL23A gene was mapped to cytogenetic band 17q11 by fluorescence in situ hybridization.

Amino Acid Sequence↗

PubMed1997

Role of melanocortinergic neurons in feeding and the agouti obesity syndrome.

Dominant alleles at the agouti locus (A) cause an obesity syndrome in the mouse, as a consequence of ectopic expression of the agouti peptide. This peptide, normally only found in the skin, is a high-affinity antagonist of the melanocyte-stimulating hormone receptor (MC1-R), thus explaining the inhibitory effect of agouti on eumelanin pigment synthesis. The agouti peptide is also an antagonist of the hypothalamic melanocortin-4 receptor (MC4-R). To test the hypothesis that agouti causes obesity by antagonism of hypothalamic melanocortin receptors, we identified cyclic melanocortin analogues that are potent agonists or antagonists of the neural MC3 (refs 11, 12) and MC4 receptors. Intracerebroventricular administration of the agonist, MTII, inhibited feeding in four models of hyperphagia: fasted C57BL/6J, ob/ob, and A(Y) mice, and mice injected with neuropeptide Y. Co-administration of the specific melanocortin antagonist and agouti-mimetic SHU9119 completely blocked this inhibition. Furthermore, administration of SHU9119 significantly enhanced nocturnal feeding, or feeding stimulated by a prior fast. Our data show that melanocortinergic neurons exert a tonic inhibition of feeding behaviour. Chronic disruption of this inhibitory signal is a likely explanation of the agouti obesity syndrome.

Agouti Signaling Protein↗

PubMed1997

Basic fibroblast growth factor treatment delays age-related photoreceptor degeneration in Fischer 344 rats.

This study was undertaken to investigate the potential of basic fibroblast growth factor (bFGF) to delay photoreceptor cell loss in retinas of Fischer 344 rats which exhibit an age-related peripheral retinopathy. Eight male 16-month-old Fischer 344 rats were injected intravitreally with 2.0 micrograms bFGF in the right eye, while the vehicle was injected into the left eye and all rats were killed at two months post-injection. Eight other Fischer rats were injected with either bFGF or vehicle at 16 and again at 18 months, then killed two months later. After enucleation, eyes were processed for light and electron microscopic and morphometric analyses. The distance from the ora serrata to the point where the outer nuclear layer (ONL) in the superior retina was two cells in thickness, called the die-back zone, that represents the extent of the peripheral retinopathy, was compared in bFGF- and vehicle-injected Fischer rats. These measurements revealed that the die-back zone in retinas of eyes injected twice with bFGF was significantly reduced (P < 0.01) when compared to this zone in retinas of age-matched rats that received vehicle injections. However, there was no significant difference (P > 0.05) in this degeneration zone in retinas of 18-month-old rats that received a single-bFGF injection when compared to retinas of respective vehicle-injected rats. In addition, the ONL at 2 and 3 mm from the ora serrata in the superior retina of bFGF-injected 20-month-old Fischer rats was significantly thicker than corresponding regions in retinas of vehicle-control rats. Furthermore, the photoreceptor cells in the superior retina of 20-month-old rats which received two injections of bFGF had normal-appearing inner and outer segments, while the few photoreceptors had short inner and outer segments in vehicle-injected retinas of Fisher rats. These findings reveal that injections of bFGF into eyes of Fischer 344 rats significantly delays the progress of photoreceptor cell degeneration suggesting that exogenous bFGF may act as a survival-promoting factor in these aged retinas.

Aging↗

PubMed1997

A transformed neonatal rat retinal pigment epithelial cell line: secreted protein analysis and fibroblast growth factor and receptor expression.

PURPOSE: A newly-derived transformed neonatal rat retinal pigment epithelial (tnrRPE) cell line was investigated: for secreted proteins by electrophoresis, and for basic and acidic fibroblast growth factor (FGF) by immunocytochemistry, Northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR). The FGFR-1 (flg) receptor, which is recognized by aFGF and bFGF, was studied by RT-PCR. METHODS: Retinal pigment epithelial (RPE) cells were isolated from 6-day-old pigmented normal Long Evans rats, and became spontaneously transformed after the second passage. RESULTS: RPE cells at the 5th through 28th passages expressed the epithelial cell marker cytokeratin and cellular retinaldehyde binding protein (CRALBP), an RPE cell marker, but were negative for glial fibrillary acidic protein (GFAP), as shown by immunofluorescence. Secreted proteins of late passage tnrRPE cells were in a narrow molecular weight range of 60-80kDa, while early passage cells exhibited multiple proteins from 20-200kDa. These tnrRPE cells increased by 17-30 fold over a 4-day culture period. At 5th and 28th passage, immunostaining for bFGF and aFGF was dense within nuclei, but light and diffuse within the cytoplasm of transformed RPE cells. As shown by Northern blot, similar levels of message for bFGF were detected in 5th and 30th passage RPE cells. As shown by Northern blot, similar levels of message for bFGF were detected in 5th and 30th passage RPE cells. Furthermore, as shown by RT-PCR, bFGF mRNA was found in freshly isolated and transformed neonatal rat RPE cells. However, the message for FGFR-1(flg) receptor was detected only in the transformed RPE cells. CONCLUSIONS: This study demonstrated a neonatal rat RPE cell line that proliferated rapidly in vitro, expressed high levels of message for hFGF and FGFR-1(flg) receptor, and continued to express RPE-cell characteristics. Importantly, mRNA levels of confluent cultures of these cells were sufficient for bFGF mRNA blot analysis, which eliminates the necessity for PCR and for using excessive numbers of animals for such studies.

Animals↗

PubMed1997

Anisotropic repolarization in ventricular tissue.

Extracellular recording and stimulation techniques have been used to demonstrate that the effective refractory period of epicardial ventricular cells is significantly influenced by the sequence of activation. Whether myocardial fiber orientation is also important in determining the repolarization process is unclear. To determine the importance of fiber orientation on the repolarization process, we studied 12 blocks of pig right ventricular tissue in vitro. The size of each tissue block was 30 x 30 x 2 mm. Transmembrane action potentials were recorded, and effective refractory periods were measured from the preparation's epicardial surface, which showed nearly uniform fiber orientation. Tissues were paced at 500- and 1,000-ms cycle lengths. Sequential recordings were made at 1, 4, 7, 10, 13, and 16 mm from the stimulation site along and across the fibers. The results show that propagation of depolarization was much slower in the transverse direction than in the longitudinal direction. In the transverse direction, action potential duration was longest at the closest observation point, i.e., 1 mm from the stimulation, site (188 +/- 14 and 267 +/- 18 ms for 500- and 1,000-ms pacing cycle lengths, respectively). Action potential duration progressively shortened as the recording site was moved farther from the stimulation site (P < 0.001). The action potential duration 16 mm from the stimulation site was 165 +/- 11 and 247 +/- 12 ms for 500- and 1,000-ms pacing cycle lengths, respectively. In contrast, the action potential duration in the longitudinal direction did not change as the distance between the recording site and stimulation site increased. We conclude that, at physiological temperature and pacing cycle lengths, sequence of activation significantly influenced action potential duration when the propagation of activation was transverse to myocardial fiber orientation. When activation propagated parallel to fiber orientation, there was little or no change of action potential duration as distance increased.

Action Potentials↗

PubMed1997

Molecular cloning of TA16, a transcriptional repressor that may mediate glucocorticoid-induced growth arrest of leiomyosarcoma cells.

The DDT1 MF2 smooth muscle tumor cell line was derived from an estrogen/androgen-induced leiomyosarcoma that arose in the ductus deferens of a Syrian hamster. The growth of this cell line is arrested at the G0/G1 phase of the cell cycle after treatment with glucocorticoids. To identify the putative gene(s) that are potentially involved in this hormone-induced cell growth arrest, we have used a differential screening technique to clone those genes whose expression is induced or up-regulated by glucocorticoids. A number of glucocorticoid response genes were thereby isolated from the leiomyosarcoma cells. One of these clones, termed TA16, was found to be markedly up-regulated by glucocorticoids in DDT1 MF2 cells, but only marginally changed in GR1 cells, a glucocorticoid-resistant variant that was selected from the wild type DDT1 MF2 cell. Isolation and sequencing of its intact cDNA indicated that the TA16 encodes a protein 485 amino acids long, and its sequence is closely homologous to a novel transcriptional repressor that presumably represses the transcription activity of some zinc finger transcriptional factors through a direct interaction. Transfection assays demonstrated that introduction of an antisense TA16 cDNA expression vector, controlled by an MMTV promoter, into the DDT1 MF2 cell significantly relieved the glucocorticoid-induced cell growth arrest. This finding suggests that TA16 might participate in the mediation of glucocorticoid-induced cell cycle arrest in leiomyosarcoma cells.

Amino Acid Sequence↗

PubMed1997

[Cloning of genes associated with taxol-induced apoptosis of human breast cancer cells].

The method of mRNA differential display was employed to isolate expressing genes involved in taxol-induced apoptosis of human breast cancer cells (BCap 37). Results demonstrated that the expressive alteration of twelve clones isolated was associated with taxol-induced apoptosis identified by Northern blot. cDNA sequence of clone C3P3 was highly homologous (99%) to human S-adenosylmethionine (S-AdoMet) synthetase. Increased transcriptional level of clone C3P3 induced by taxol was parallel to enhanced enzyme activity of S-AdoMet synthetase. These results suggested that the expression of these clones isolated by the mRNA differential display be possibly involved in the regulation of taxol-induced apoptosis. Their function in details need further study.

Antineoplastic Agents, Phytogenic↗

PubMed1997

[Influence of intercellular adhesion molecule-1 transcription on nasal epithelial cell by airborne allergenic pollens].

Eleven patients with Artemisia allergic rhinitis were evaluated. Among them 8 were studied during pollen season and 3 out of pollen season. Intercellular adhesion molecule-1(ICAM-1) was detected on nasal epithelial cells by reverse transcription polymerase chain reaction (RT-PCR). The results showed that ICAM-1 was detectable from all samples in the pollen season. However, during off-pollen season 2 of the 3 samples were negative, 1 was positive (who was also positive to house dust). It is suggested that ICAM-1 is detectable on nasal epithelial cells during exposure to specific allergen.

Adolescent↗

PubMed1997

[CT diagnosis of maxillary sinus diseases].

To evaluate the diagnostic value of CT scan in maxillary sinus diseases, CT findings in 100 cases of maxillary sinus diseases, which included 64 inflammatory diseases; 14 benign tumors; 17 malignant tumors and 5 fractures The result showed that the accordance rate between CT scan and operative diagnosis was 95.0%; between CT scan and pathology was 92.6%(88/95). It is concluded that CT scan showed a better visualization of maxillary sinus than X-ray tomogram.

Adolescent↗

PubMed1997

[The relationship between smoking and periodontal diseases].

The oral hygiene, periodontal status and smoking habits of 432 males were surveyed in order to study the relationship between smoking and periodontal disease. The results showed that there was no difference between smokers and non-smokers on oral hygiene and gingivitis. The percentage of smokers with periodontitis was higher than that of non-smokers. The prevalence of periodontitis in heavy smokers was higher than that of light and middle smokers and non-smokers. It was indicated that smoking may be one of the risk factors in the development of periodontal disease.

Adult↗

PubMed1997

[Extraction-flame atom absorption determination of trace copper, zinc, cadmium and iron in bones].

Trace content of Cu, Zn, Cd and Fe in bones is determined by flame atomic absorption spectrometry after preceding preconcentration using the extraction system O-phenanthroline-sodium perchlorate/1, 2-dichloroethane. Also, the factors of influence were studied. The method was simple, accurate and reliable, The detection limits were Cu: 0.038microg/ml, Zn: 0.0042microg/ml, Cd: 0.0019microg/ml, Fe: 0.02microg/ml. The recovery rate was between 92.8 and 105%.

Analytic Sample Preparation Methods↗

PubMed1997

Coxsackievirus B3-induced myocarditis. Characterization of stable attenuated variants that protect against infection with the cardiovirulent wild-type strain.

Coxsackievirus B3 (CVB3) is the enterovirus most frequently involved in human myocarditis or dilated cardiomyopathy. Attenuated variants were derived from a cardiovirulent CVB3 reactivated from a sequenced, full-length cDNA clone. The prophylactic potential of these variants was assessed in SWR/Ola (H-2q) mice. Animals immunized with attenuated variants of CVB3 were protected from myocarditis when challenged subsequently with the cardiovirulent wild-type virus. In contrast to nonimmunized controls, the wild-type virus was not isolated from myocardium of protected mice, nor was viral RNA detected in myocardium by reverse transcription nested polymerase chain reaction. Specific antibody to CVB3 was demonstrated by virus neutralization assay and by indirect immunofluorescence. The attenuated phenotype of one variant, p14V-1, remained stable throughout 20 consecutive passages in SWR mice and induced a markedly lower level of autoantibody against mouse cardiac myosin heavy chain than the cardiovirulent wild type. These data demonstrate that attenuated strains protect against CVB3-induced myocarditis in mice, that the attenuated phenotype is stable, and that they do not persist in myocardium nor induce a significant level of anti-heart anti-body against myosin heavy chain. These attenuants may be the basis of a live vaccine against CVB3 in the prevention of enteroviral heart muscle disease.

Animals↗

PubMed1997

Tissue and differentiation specific expression on the endogenous retrovirus ERV3 (HERV-R) in normal human tissues and during induced monocytic differentiation in the U-937 cell line.

ERV3 (HERV-R) is a complete, single copy human endogenous retrovirus located on the long arm of chromosome 7. The open reading frame in its envelope gene has been conserved during evolution but the gag and pol genes contain in-frame termination codons. To find a suitable experimental model system for analysis of the functions of the ERV3 genome, an extensive screening study of different normal and neoplastic human tissues was performed. Most tissues express low levels of the ERV3 env mRNA although high expression levels are observed in placenta, sebaceous glands, adrenals, testis, bronchial, epithelium and the monocytic cell line U-937. In U-937 cells the ERV3 env expression varied in a manner related to the differentiation status of the cells; being highest in the terminally differentiated non proliferating cells. U-937 cells can be induced to differentiate from the monoblastic to the mature monocyte/macrophage stage upon stimulation by several substances such as phorbolesters (TPA), Vitamin D3, Retinoic Acid (RA) and combinations of some cytokines. We conclude that the ERV3 locus is expressed in a tissue and differentiation specific way and that the U-937 cell line is a suitable model system to further analyze the proposed functions of ERVs such as immunomodulation, cell fusion and protection against exogenous retroviral infections.

Cell Differentiation↗