Search PubMed⌕ Search

Biomedical subjects

J Fang

Publications and source records attributed to J Fang.

At least 181 records · Page 10Linked to original sources
PubMed1999

[Expression and stability of fragment of Plasmodium merozoite major surface protein 1 in recombinant attenuated Salmonella typhimurium].

OBJECTIVE: To determine the invasive ability of recombinant attenuated Salmonella typhimurium X4064 (pQEM1) strain containing gene fragment of Plasmodium falciparium merozoite surface protein 1 (MSP1), the stability of its plasmid, and its re-expression. METHODS: BALB/c mice were fed with recombinant attenuated S. typhimurium containing No. 1 gene fragment of P. falciparium MSP1 by gastric tube. Plate incubation, plasmid endonuclease analysis and Western blot were used to identify the recombinant attenuated S. typhimurium strains isolated from mice and the ability of re-expression, and its growth were determined in vitro. RESULTS: The attenuated strain X4064 of S. typhimurium isolated from mice contained recombinant plasmid pQEM1, no. 1 MSP1 fragment of P. falciparium was expressed in vitro in S. typhimurium X4064 (pQEM1) strain, and its growth curve of X4064 (pQEM1) strain in mice was basically similar to that of X4064. CONCLUSION: The recombinant plasmid pQEM1 could steadily exist in the X4064 strain of S. typhimurium, without influence on its invasion into host cells. X4060 (pQEM1) strain isolated from infected mice still had the ability to re-express M1 protein.

Animals↗
PubMed1999

[Quality of life as a time-dependent covariable in cox regression analysis and its application].

OBJECTIVE: To present a statistical method for combined evaluation of the quality of life and survival time and to study some issues in its application. METHODS: Based on Cox regression model, quality of life was used as a time-dependent covariable in analysis of the influence factors for the effectiveness of detoxification in 212 drug addicts. RESULTS: The influence factors entered the regression equation were ways of detoxification for drug abusers, marital status, mode of drug abuse, frequency of detoxification, maternal educational level, maternal occupation, family atmosphere and help and encourage from their relatives and friends, with their hazard ratios of 0.673, 1.315, 1.319, 0.867, 1.120, 1.318, 0.724 and 1.150, respectively. CONCLUSION: Combined statistical analysis of quality of life and survival time was a better method for the evaluation of the effectiveness of detoxification and its influence factors, which depended mainly on their mother's qualification, family atmosphere, mode and length of drug abuse, etc.

Humans↗
PubMed1999

[Cloning and sequencing of the genes coding for the histidine-rich protein II of Plasmodium falciparum].

AIM: To compare and analyze the homology of genes encoding histidine-rich proteinII (HRPII) of different Plasmodium falciparum isolates. METHODS: Using PCR technique, the complete genes coding for HRPII of P. falciparum isolates FCC1/HN and VN isolates were amplified. PCR products were digested by HindIII/BamHI and cloned into plasmid pUC19. The recombinant plasmid HRPII/pUC19 was screened and identified by PCR and restriction analysis. The cloned HRPII genes were sequenced by Sanger's method. RESULTS: HRPII genes of FCC1/HN and VN isolates were successfully amplified and cloned into pUC19. DNA sequencing showed that the coding length of HRPII gene was 1,020 bp without introns in FCC1/HN and VN isolates, however, there were ten points mutations between them. FCC1/HN isolate exhibited 98.8%, 92.2% and 98.7% homology in amino acids with isolates VN, IMTM22, and Itg2, respectively. Though the numbers of repeat sequences were different in four isolates, they had the same hydrophobic leader sequence and a single putative glycosylation site. The secondary structure analysis showed that the main antigenic determinants of four isolates were located on 5' end non-repeat region (amino acids 1-60). CONCLUSION: FCC1/HN isolate was highly homologous in the coding region of HRPII with VN, IMTM22, and Itg2 isolate. Four isolates exhibited similar structural characteristics and antigenic determinants in HRPII.

Amino Acid Sequence↗
PubMed1999

[Determination of zinc in vegetable oils by FAAS with trace injection method].

A method for the determination of zinc in the soybean, cottonseed and sesame oils by FAAS with trace injection technique was discribed in this paper. The injection volume was 30 microL. The characteristic concentration and the detection limit were 0.098 and 0.00368 microg/g, respectively. The relative standard deviation was 2.6% and the recoveries were in the range of 92.9%-107.8%. The contents of zinc in the samples were 9.67, 1.42 and 1.77 microg/g, respectively.

Limit of Detection↗
PubMed1999

Synthetic influenza viral double-stranded RNA induces an acute-phase response in rabbits.

Numerous studies have characterized the physiological effects of synthetic, high-molecular-weight, homopolymeric, double-stranded RNA (dsRNA), particularly polyriboinosinic.polyribocytidylic acid [Carter and De Clercq (1974): Science 186:1172-1178], but limited information exists regarding the physiological effects of dsRNA of viral composition and size. In this report, we determined sleep and fever responses of rabbits to intracerebroventricular injection of different doses of synthetic viral dsRNA (either 108 base pairs or 661 base pairs) derived from the N-terminal sequence of gene segment 3 of the A/PR/8/34-H1N1 (PR8) influenza virus. Both the108-mer and the 661-mer dsRNAs increased nonrapid eye movement sleep, suppressed rapid eye movement sleep, and induced fever. The 661-mer dsRNA had more potent somnogenic and pyrogenic effects than the 108-mer dsRNA on the basis of weight. Neither single-stranded RNA from the corresponding sequences had significant effects on sleep or brain temperature. These results demonstrate for the first time that low-molecular-weight, viral dsRNA has the stability in vivo that is required to induce the fever and sleep changes found in natural viral infections, and the hypothesis is supported that virus-associated dsRNA may be responsible for initiating the acute-phase response during viral infections.

Acute-Phase Reaction↗
PubMed1998

Design and synthesis of novel alpha1a adrenoceptor-selective dihydropyridine antagonists for the treatment of benign prostatic hyperplasia.

We report the synthesis and evaluation of novel alpha1a adrenoceptor subtype-selective antagonists. Systematic modification of the lipophilic 4,4-diphenylpiperidinyl moiety of the dihydropyridine derivatives 1 and 2 provided several highly selective and potent alpha1a antagonists. From this series, we identified the 4-(methoxycarbonyl)-4-phenylpiperidine analogue SNAP 5540 (-) [(-)-63] for further characterization. When examined in an isolated human prostate tissue assay, this compound was found to have a Ki of 2.8 nM, in agreement with the cloned human receptor binding data (Ki = 2.42 nM). Further evaluation of the compound in isolated dog prostate tissue showed a Ki of 3.6 nM and confirmed it to be a potent antagonist (Kb = 1.6 nM). In vivo, this compound effectively blocked the phenylephrine-stimulated increase in intraurethral pressure (IUP) in mongrel dogs, at doses which did not significantly affect the arterial pressure (diastolic blood pressure, DBP), with a DBP Kb/IUP Kb ratio of 16. In addition, (-)-63 also showed greater than 40 000-fold selectivity over the rat L-type calcium channel and 200-fold selectivity over several G protein-coupled receptors, including histamine and serotonin subtypes. These findings prove that alpha1a adrenoceptor-subtype selective antagonists such as (-)-63 may be developed as uroselective agents for an improved treatment of BPH over nonselective alpha1 antagonists such as prazosin and terazosin, with fewer side effects.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1998

Measurements of the Surface Elasticity in Medium Frequency Range Using the Oscillating Bubble Method.

Various experimental techniques are available for the investigation of dynamic surface tension, and a generally accepted theoretical model of these dynamics has been established. However, reliable rheological parameters of a fluid surface are very scarce. Therefore, comparisons of rheological parameters resulting from slow and faster processes or from theoretical calculations are required. In particular, a comprehensive experimental verification of the complex surface elasticity modulus which characterizes the dynamic behavior of a fluid surface in an appropriate manner is desirable. For this reason a new version of oscillating bubble method was developed which allows exact measurements of the complex elasticity modulus in the frequency range 3-500 Hz. With this method the assumptions of the theory of dynamic surface tension can be verified for medium frequencies. The new experimental results, in particular the experimental determination of the Gibbs elasticity, reveal that these assumptions are only approximately valid for faster processes. However, with a slight modification of the established model the experimental results can be explained. These experiments were carried out with solutions of tridecyl dimethyl phosphine oxide, fatty acids, n-alkanols, and triton X-100 at different surfactant concentrations. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Human CYP2D6 and metabolism of m-chlorophenylpiperazine.

BACKGROUND: Metabolic drug-drug interactions can occur between drugs that are substrates or inhibitors of the same cytochrome P450 (CYP) isoenzymes, but can be prevented by knowing which isoenzymes are primarily responsible for a drug's metabolism. m-Chlorophenylpiperazine (mCPP) is a psychopharmacologically active metabolite of four different psychiatric drugs. The present experiments were designed to identify the CYP isoenzymes involved in the metabolism of mCPP to its main metabolite p-hydroxy-mCPP (OH-mCPP). METHODS: The rate of production of OH-mCPP from mCPP was correlated with isoform activities in a panel of human liver microsomes, was assessed using a panel of individual complementary DNA-expressed human CYP isoenzymes, and was investigated in the presence of a specific inhibitor of CYP2D6. RESULTS: OH-mCPP production correlated significantly with CYP2D6 activity in human liver microsomes. Furthermore, incubations with microsomes from cells expressing CYP2D6 resulted in OH-mCPP formation, whereas no mCPP was formed from incubations with microsomes from cells expressing other individual isoforms. Finally, when the specific CYP2D6 inhibitor quinidine was preincubated with either human liver microsomes or cells expressing human CYP2D6, there was a concentration-dependent decrease in the production of OH-mCPP. CONCLUSIONS: These results confirm that CYP2D6 is the isoform responsible for the p-hydroxylation of mCPP, and indicate that caution should be exercised in coprescribing inhibitors or substrates of CYP2D6 with drugs that have mCPP as a metabolite.

Cytochrome P-450 CYP2D6↗
PubMed1998

Role of endogenous interferon-gamma on the enhancement of splenic NK cell activity by electroacupuncture stimulation in mice.

Successive electro-acupuncture (EA) stimulation applied to bilateral anterior tibial muscles, where Zusanli (ST36) acupoints are located, once a day (30 min) for 3 successive days significantly enhanced splenic natural killer (NK) cell activity in BALB/c mice. The percentage of splenic NK cells, as measured by flow cytometry, was not affected in these mice. Interferon (IFN)-gamma level in splenic aqueous extract, prepared from the ST36 acupoint-stimulated mice, was significantly higher than that of the controls. In vivo treatment with neutralizing monoclonal antibody against mouse IFN-gamma completely abrogated the increase in splenic NK cell activity induced by ST36 acupoint stimulation. The same stimulation also significantly increased the concentration of splenic beta-endorphin, which coincided with the significant increase in splenic IFN-gamma production. Pre-administration of 10 mg/kg naloxone before initiation of EA stimulation every day reduced the enhancements of NK cell activity and IFN-gamma level. These observations strongly suggest that endogenous IFN-gamma mediates the up-regulation of NK cell activity by EA stimulation at the ST36 acupoints. Furthermore, endogenous beta-endorphin secreted by EA stimulation also plays an important role in the up-regulation of NK cell function, which may be realized through regulating IFN-gamma production.

Animals↗
PubMed1998

Increased caveolin-3 levels in mdx mouse muscles.

The density of skeletal muscle caveolae is increased in Duchenne muscular dystrophy and its genetic homologue, the mdx mouse. This structural change is significant as it may indicate muscle regeneration. We identified in mdx mouse tibialis anterior muscles significantly increased levels of caveolin-3, the chief protein in muscle caveolae, and reduced levels of neuronal nitric oxide synthase, an enzyme regulated by caveolin-3. Similar changes occurred in the corresponding mRNA levels. These data suggest that induction of caveolin-3 occurs and this may at least partly be responsible for increased number of caveolae, altered nNOS-caveolin cycle, and regeneration of dystrophic muscles.

Animals↗
PubMed1998

Identification of a dihydropyridine as a potent alpha1a adrenoceptor-selective antagonist that inhibits phenylephrine-induced contraction of the human prostate.

A number of novel dihydropyridine derivatives based upon 1, 4-dihydro-3-(methoxycarbonyl)-2, 6-dimethyl-4-(4-nitrophenyl)-5-((3-(4, 4-diphenylpiperidin-1-yl)propyl)aminocarbonyl)pyridine (4) have been synthesized and tested at cloned human alpha adrenoceptors as well as the rat L-type calcium channel. Within this compound series, 5-(aminocarbonyl)-1,4-dihydro-2, 6-dimethyl-4-(4-nitrophenyl)-3-((3-(4, 4-diphenylpiperidin-1-yl)propyl)aminocarbonyl)pyridine (19) displayed good binding affinity and selectivity for the alpha1a adrenoceptor (pKi = 8.73) and potently inhibited (pA2 = 9.23) phenylephrine-induced contraction of the human prostate.

Adrenergic alpha-Agonists↗
PubMed1998

Cellobiose dehydrogenase from Schizophyllum commune: purification and study of some catalytic, inactivation, and cellulose-binding properties.

Cellobiose dehydrogenase (CDH) of Schizophyllum commune was purified to homogeneity. It is a glycoprotein with a molecular mass of 102, 000. Cellulosic substrates can serve as substrates for CDH. Cytochrome c, dichlorophenol-indophenol, ferricyanide, and oxygen can be reduced by the enzyme. CDH is stable in the pH range of 4-11 and up to 35 degrees C. The enzyme keeps active at high concentrations of H2O2. In the presence of cellobiose and Fe3+, incubation of CDH resulted in its inactivation and the degree of the inactivation was dependent mainly on the amount of CDH and cellobiose present. CDH has a distinct and specific affinity to cellulose and showed the strongest binding to acid-treated cellulose. The adsorption isotherm data fitted the Langmuir-type equation. The uv-visible spectra of the oxidized and reduced states of CDH showed a typical cytochrome b-type pattern. Addition of dithionite eliminated the adsorption between 440 and 500 nm, which indicates the presence of a flavin group in CDH.

Carbohydrate Dehydrogenases↗
PubMed1998

Epstein-Barr virus growth-transformed cells are converted to malignancy following transfection of a 1.3-kb CATR1 antisense construct independent of a change in the level of c-myc expression followed by a 8;14 chromosomal translocation.

The AGLCL Epstein-Barr virus (EBV) growth-transformed cell line is incapable of inducing tumors in nude mice. When the cells were transfected with a 1.3-kb CATR1 antisense cDNA construct, progressively growing lymphomas could be induced in nude mice. Chromosome analysis of the parental, transfected, and tumor cells revealed that a chromosomal translocation t(8;14)(q24.1;q32) had occurred in the transfected cells and was retained in cells derived from tumors. Moreover, enhanced c-myc expression, usually associated with this translocation, was either unchanged or under-expressed. These data suggest that the malignant transformation of the EBV growth-transformed cells was independent of c-myc expression and suggest that the CATR1 gene may act synergistically with the chromosomal translocation facilitating the conversion of AGLCL cells from a growth-transformed state to a malignant phenotype.

Animals↗
PubMed1998

8-Cysteine TGF-BP structural motifs are the site of covalent binding between mouse LTBP-3, LTBP-2, and latent TGF-beta 1.

The small latent TGF-beta complex often is associated with the latent TGF-beta binding protein (LTBP). Three LTBPs (LTBP-1, -2, and -3) have been isolated to date. Previous studies have shown that LTBP-1 binds the small latent TGF-beta 1 complex through a disulfide bond between an 8-cysteine structural motif of LTBP-1 (TGF-bp repeat) and the propeptide dimer of latent TGF-beta 1 (TGF-beta 1 latency associated peptide). There is indirect evidence that LTBP-2 and LTBP-3 also bind the latent TGF-beta complex, but the nature and location of the binding interaction are unknown. We have used immunoprecipitation, SDS-PAGE, and autoradiography to characterize the association between mouse LTBP-3 and the small latent TGF-beta 1 complex. We report that the second and third TGF-bp repeats of LTBP-3 covalently bind the latent complex, and we show a similar capability for the homologous TGF-bp repeats of mouse LTBP-2. The second TGF-bp repeat of LTBP-3 is unusual in that it has 9 cysteine residues instead of 8, and our results provide the first evidence that a TGF-bp repeat with an odd number of cysteine residues can covalently bind latent TGF-beta 1. Altogether, these results have important implications for TGF-beta biosynthesis and the regulation of TGF-beta activity.

Adaptor Proteins, Signal Transducing↗
PubMed1998

An interleukin-1 receptor fragment blocks ambient temperature-induced increases in brain temperature but not sleep in rabbits.

The effects of intracerebroventricular injection (i.c.v.) of an interleukin-1 (IL-1) inhibitor, a soluble IL-1 receptor fragment (IL-1RF), on sleep and brain temperature (Tbr) responses of rabbits induced by mild increases in ambient temperature (Tamb) were determined. Each rabbit was recorded under three conditions: (1) 21 degrees C Tamb plus pyrogen-free saline (PFS); (2) 27 degrees C Tamb plus PFS; (3) 27 degrees C Tamb plus the IL-1RF. The higher Tamb significantly increased Tbr during the warming period; this effect was attenuated by pretreatment with the IL-1RF. The higher Tamb alone (6 h exposure) significantly increased non-rapid eye movement sleep (NREMS) across the 23-h recording period. However, during the 6-h warming period NREMS values, obtained after IL-1 RF treatment, were not significantly different from those obtained from PFS-treated animals at 27 degrees C Tamb. The ability of the IL-1 RF to block Tamb-induced changes in Tbr and the failure of the IL-1RF to block Tamb-induced NREMS responses is different from previous results which indicated that a tumor necrosis factor receptor fragment (TNF-RF) inhibits warm Tamb-induced sleep but not Tbr responses. Thus, brain IL-1 and TNF sleep and thermo mechanisms are, in part, different.

Animals↗