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Biomedical subjects

P Wu

Publications and source records attributed to P Wu.

At least 55 records · Page 3Linked to original sources
PubMed2001

In vivo and in vitro measurement of apoptosis in breast cancer cells using 99mTc-EC-annexin V.

OBJECTIVE: The purpose of this study was to develop an imaging technique to measure and monitor tumor cells undergoing programmed death caused by radiation and chemotherapy using 99mTc-EC-annexin V. Annexin V has been used to measure programmed cell death both in vitro and in vivo. Assessment of apoptosis would be useful to evaluate the efficacy and mechanisms of therapy and disease progression or regression. METHODS: Ethylenedicysteine (EC) was conjugated to annexin V using sulfo-N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-HCl as coupling agents. The yield of EC-annexin V was 100%. In vitro cellular uptake, pre- and post-radiation (10-30 Gy) and paclitaxel treatment, was quantified using 99mTc-EC-annexin V. Tissue distribution and planar imaging of 99mTc-EC-annexin V were determined in breast tumor-bearing rats at 0.5, 2, and 4 hrs. To demonstrate in vivo cell apoptosis that occurred during chemotherapy, a group of rats was treated with paclitaxel and planar imaging studies were conducted at 0.5-4 hrs. Computer outlined region of interest (ROI) was used to quantify tumor uptake on day 3 and day 5 post-treatment. RESULTS: In vitro cellular uptake showed that there was significantly increased uptake of 99mTc-EC-annexin V after irradiation (10-30 Gy) and paclitaxel treatment. In vivo biodistribution of 99mTc-EC-annexin in breast tumor-bearing rats showed increased tumor-to-blood, tumor-to-lung and tumor-to-muscle count density ratios as a function of time. Conversely, tumor-to-blood count density ratios showed a time-dependent decrease with 99mTc-EC in the same time period. Planar images confirmed that the tumors could be visualized clearly with 99mTc-EC-annexin. There was a significant difference of ROI ratios between pre- and post-paclitaxel treatment groups at 2 and 4 hrs post injection. CONCLUSION: The results indicate that apoptosis can be quantified using 99mTc-EC-annexin and that it is feasible to use 99mTc-EC-annexin to image tumor apoptosis.

Animals↗
PubMed2001

The inhibition and selectivity of bacterial topoisomerases by BMS-284756 and its analogues.

Analogues of BMS-284756, a novel des-F(6)-quinolone, were synthesized and evaluated in order to determine the effects of modification of substituents on in vitro target inhibition. BMS-340281 (stereoisomer of BMS-284756), BMS-340280 (C-6 fluorinated analogue of BMS-284756), BMS-340278 (C-8-H derivative), BMS-433366 (C-8 methoxy analogue) and fluoroquinolone comparators were evaluated for antibacterial activity. The MICs of BMS-284756 were generally found to be within two-fold of the MICs of BMS-284756 analogues against a panel of Gram-positive and -negative organisms. BMS-284756 had MICs of 0.03-0.125 mg/L against Streptococcus pneumoniae strains with GyrA and ParC mutations, and was the most active quinolone. BMS-284756 and its analogues had similar activity compared with ciprofloxacin and moxifloxacin against topoisomerase IV decatenation, but were three times more active than levofloxacin. The IC(50) of BMS-284756 for human topoisomerase II (hTopo II) was 3000 times higher than its IC(50) for DNA gyrase, and no whole-cell cytotoxicity was noted. Two analogues, BMS-340280 and BMS-340278, demonstrated moderate inhibition against hTopo II and cytotoxicity in the cellular assay. BMS-284756 demonstrated greater Gram-positive antibacterial activity and similar inhibition of targets compared with other fluoroquinolones, and more favourable selectivity compared with the other BMS-284756 analogues.

Anti-Infective Agents↗
PubMed2001

Effect of cytosine protonation and cation on thermodynamic properties of parallel DNA triplex family.

The conformational and thermodynamic properties of three modified parallel triplexes, which have the same base composition but differ in the orientation of the Hoogsteen third strand with respect to the core duplex, were comparatively discussed. The results show that the intermolecular triplex is unstable relatively to the intramolecular triplex and the thermodynamic properties are slightly dependent on the 3' or/and 5' junctions. Furthermore, mono- and divalent cations compete each other in stabilizing the triple helix structure and a higher concentration of the monovalent cation would shield the effect of divalent cations on the triplex stability.

Base Sequence↗
PubMed2001

Identification of protein kinases dysregulated in CD4(+) T cells in pathogenic versus apathogenic simian immunodeficiency virus infection.

Human immunodeficiency virus infection in humans and simian immunodeficiency virus (SIV) infection in rhesus macaques (RM) leads to a generalized loss of immune responses involving perturbations in T-cell receptor (TCR) signaling. In contrast, naturally SIV-infected sooty mangabeys (SM) remain asymptomatic and retain immune responses despite relatively high viral loads. However, SIV infection in both RM and SM led to similar decreases in TCR-induced Lck phosphorylation. In this study, a protein tyrosine kinase (PTK) differential display method was utilized to characterize the effects of in vivo SIV infection on key signaling molecules of the CD4(+) T-cell signaling pathways. The CD4(+) T cells from SIV-infected RM, but not SIV-infected SM, showed chronic downregulation of baseline expression of MLK3, PRK, and GSK3, and symptomatically SIV-infected RM showed similar downregulation of MKK3. In vitro TCR stimulation with or without CD28 costimulation of CD4(+) T cells did not lead to the enhancement of gene transcription of these PTKs. While the CD4(+) T cells from SIV-infected RM showed a significant increase of the baseline and anti-TCR-mediated ROR2 transcription, SIV infection in SM led to substantially decreased anti-TCR-stimulated ROR2 transcription. TCR stimulation of CD4(+) T cells from SIV-infected RM (but not SIV-infected SM) led to the repression of CaMKKbeta and the induction of gene transcription of MLK2. Studies of the function of these molecules in T-cell signaling may lead to the identification of potential targets for specific intervention, leading to the restoration of T-cell responses.

Animals↗
PubMed2001

Human skeletal muscle PDH kinase activity and isoform expression during a 3-day high-fat/low-carbohydrate diet.

The increase in skeletal muscle pyruvate dehydrogenase kinase (PDK) activity was measured in skeletal muscle of six healthy males after a eucaloric high-fat/low-carbohydrate (HF/LC; 5% carbohydrate, 73% fat, and 22% protein of total energy intake) diet compared with a standardized prediet (50% carbohdyrate, 30% fat, and 21% protein). Biopsies were obtained from the vastus lateralis muscle after 3 days on the prediet (day 0) and after 1, 2, and 3 days of the HF/LC diet. Intact mitchondria were extracted from fresh muscle and analyzed for PDK activity and Western blotting of PDK2 and PDK4 protein. A second biopsy was taken at each time point and frozen for Northern blot analysis of PDK2 and PDK4 mRNAs. PDK activity increased in a linear fashion over the 3-day HF/LC diet and was significantly higher than control by 1 day. PDK activity was 0.09 +/- 0.03, 0.18 +/- 0.05, 0.30 +/- 0.07, and 0.37 +/- 0.09 min(-1) at 0, 1, 2, and 3 days, respectively. PDK4 protein and mRNA increased maximally by day 1, and PDK2 protein and mRNA were unaffected by the HF/LC diet. Resting respiratory exchange ratios decreased after 1 day of the HF/LC diet (from 0.79 +/- 0.02 to 0.72 +/- 0.02) and remained depressed throughout the 3-day dietary intervention (0.68 +/- 0.01). The immediate shift to fat utilization was accompanied by increased blood glycerol, beta-hydroxybutyrate, and plasma free fatty acid concentrations. These results suggest that the continuing increase in PDK activity over the 3-day HF/LC diet is not due to increasing PDK protein beyond 1 day. This could be due to the contribution of another isoform to the total PDK activity or to a continual increase in PDK4 or PDK2 specific activity.

Adult↗
PubMed2001

Effects of long-term enalapril and losartan therapy of hypertension on cardiovascular aldosterone.

BACKGROUND: Plasma aldosterone escape is found during long-term angiotensin-converting enzyme inhibitor therapy. Evidence for aldosterone production in cardiovascular tissues raised the question of whether or not aldosterone escape occurs in these tissues. METHOD: Spontaneously hypertensive rats were treated with enalapril (20 mg/kg/day) and losartan (50 mg/kg/day) for 20 weeks; untreated spontaneously hypertensive and Wistar rats were used as positive and normal controls, respectively. Ex vivo mesenteric artery and heart perfusion, high-performance liquid chromatography, and radioimmunoassay for aldosterone were performed. RESULTS: The results showed that enalapril failed to significantly inhibit aldosterone production in mesenteric artery, myocardium and plasma. Losartan significantly inhibited aldosterone production to that of Wistar rats in the mesenteric artery, myocardium and plasma. CONCLUSION: This study provides the first evidence that long-term angiotensin-converting enzyme inhibition therapy induces aldosterone escape in hypertensive cardiovascular tissues, and angiotensin II subtype 1 receptor antagonist does not induce aldosterone escape in mesenteric artery, myocardium and plasma of spontaneously hypertensive rats.

Aldosterone↗
PubMed2001

Factors associated with use of mental health services for depression by children and adolescents.

OBJECTIVE: This study examined patterns of mental health service use among depressed children and adolescents and factors associated with help seeking and treatment modalities. METHODS: The sample consisted of 206 children and adolescents aged 9 to 17 years who were assessed as part of a larger survey of mental health service use in five service systems and in the community and who met DSM-III-R criteria for depressive disorders (major depression or dysthymia). RESULTS: Among the 206 children, 75 (36 percent) never received professional help for depressive symptoms. Among the 131 children who received professional help for depression, antidepressants were prescribed for 40 (31 percent) in the year before the interview. The findings indicate possible undertreatment of depression among children and adolescents, especially among African Americans. Socioeconomic factors, such as the mother's education and the child's health insurance, were not associated with receiving professional help for depressive symptoms but were associated with receiving antidepressants. Parental perception of a child's mental health service need was associated with receiving professional help but not with receiving antidepressants. Also, depressed children were more likely to receive antidepressants when they had life-threatening or severe symptoms, such as a suicide attempt or drug abuse. CONCLUSIONS: Whether a depressed child receives mental health services and the types of treatment received are influenced by different individual and family factors and by the type of symptoms exhibited. Better understanding of these factors will help in meeting the service needs of depressed children and adolescents.

Adolescent↗
PubMed2001

Differentiation of stromal-vascular cells isolated from canine adipose tissues in primary culture.

A culture condition supporting adipocyte differentiation of stromal-vascular (S-V) cells isolated from canine adipose tissues was established. Morphological observation and determination of glycerol-3-phosphate dehydrogenase (GPDH) activity were used as the criteria for adipocyte differentiation. After reaching confluence, the cells were able to undergo terminal adipocyte differentiation by treatment with 100 microM indomethacin, 10 microg/ml insulin and 0.5 mM 1-methyl-3-isobutylxanthine (MIX) in medium supplemented with 5% fetal calf serum (FCS). In the absence of either indomethacin or insulin, the S-V cells did not undergo adipose conversion and GPDH activity was not increased, indicating that both indomethacin and insulin play essential roles in this culture system. The S-V cells from inguinal adipose tissues exhibited the greatest increase in GPDH activity among the four depots (inguinal > abdominal-subcutaneous > perirenal > omental). demonstrating that adipocyte differentiation was also intensely dependent on anatomic sites from which the S-V cells were derived. Interestingly, dimethylsulfoxide (DMSO) was found to accelerate adipocyte differentiation in combination with indomethacin and insulin. Under this condition, up to 90% of the cells displayed adipocyte phenotypes and the GPDH activity reached 1288 +/- 441 mU/mg protein. This culture system may be useful for investigating other adipogenic factors as well as anti-adipogenic factors involved in the regulation of canine adipose tissue development.

1-Methyl-3-isobutylxanthine↗
PubMed2001

[QTL analysis for epistatic effects and QTL x environment interaction effects on final height of rice (Oryza sativa L.)].

QTLs with epistatic effects and environmental interaction effects for final height of rice were studied by mixed-model based QTL mapping with a doubled haploid population from IR64/Azucena in four environments. The results demonstrated the importance of epistasis as a genetic basis of the quantitative traits and also revealed several important features of this phenomenon. In the results, 100 per cent of QTLs were involved in epistasis, of which 64 per cent were found with significant additive effects. This might mean that the usual estimates of the QTL additive effects could be confounded by epistatic interactions and result in biased estimation unless epistatic effect is separated. The other 36 per cent did not have any significant additive effects of their own but were involved in 48 per cent of the identified epistatic interactions. Such loci might play the role of modifying agents that tend to activate other loci or modify the action of other loci. The other features of epistasis include as follows: it was fairly common for the same locus to get involved in interactions with more than one locus; the QTLs with relatively high magnitude of effects might also be involved in epistasis; and epistasis was sensitive to environmental interactions for their expression. QTL x environment (QE) interaction effects were detected more often than QTL main effects for plant height behavior, as might indicate that gene expression could be greatly affected by environments.

Chromosome Mapping↗
PubMed2001

[CYP11B2 expression in rat liver and the efficacy of antisterone on liver fibrosis].

OBJECTIVE: To identify aldosterone synthase gene-CYP11B2 mRNA expression in rat livers and evaluate the efficacy of antisterone. METHODS: One hundred and twenty male Wistar rats were divided into 3 groups: model group (subcutaneous injection of CCl(4), 0.25 ml/100 mg, 3 times/week), antisterone group (besides same dosage of CCl(4) given, gastropufusion of antisterone of 20mg x kg(-1) x d(-1)), and control group (subcutaneous injection of olive oil). The area of collagen was examined by image analyzing system. The expression of aldosterone synthase gene-CYP11B2 mRNA was detected by RT-PCR and in situ hybridization. RESULTS: The expression of CYP11B2 mRNA, which located in the endoplasm of HSC, was upregulated when fibrogenesis occurred. The grade of fibrosis and the area of collagen in antisterone group were less than those in model group before 6th week (P<0.05). After the 6th week however, there was no significant difference between the two groups (P>0.05). CONCLUSIONS: The expression of CYP11B2 mRNA is upregulated in fibrotic liver. Antisterone can partly have a fibrogenesis-inhibiting effect on the early stage of CCl(4)-induced hepatic fibrosis.

Animals↗
PubMed2001

Effects of moxa-cone moxibustion at Guanyuan on erythrocytic immunity and its regulative function in tumor-bearing mice.

In the sarcoma S180 ascitic mice, the effects of moxa-cone moxibustion at Guanyuan (CV 4) on erythrocytic immunity and its regulative function were investigated. The results indicated that moxibustion at Guanyuan (CV 4) could significantly increase the decreased erythrocytic C3b receptor rosette forming rate (RBC-C3bRR), lower the raised erythrocytic immunocomplex rosette forming rate (RBC-ICR, P < 0.05 or P < 0.01), increase the decreased activity of erythrocytic immuno-accelerative factor, and reduce the increased activity of erythrocytic immunosuppressive factor (P < 0.05) in the tumor-bearing mice. This suggests that moxibustion at Guanyuan (CV 4) can strengthen erythrocytic immunity and promote its regulative function.

Acupuncture Points↗
PubMed2001

Elevated interleukin-13 in patients with active lupus nephritis.

OBJECTIVE: To investigate the significance of interleukin-13 (IL-13) in patients with active lupus nephritis (LN). METHODS: Ten healthy volunteers and 16 patients with active LN were included in this study. The protein level of IL-13 in plasma was examined by enzyme linked immunosorbent assay (ELISA), and gene expression of IL-13 in peripheral blood mononuclear cells (PBMCs) by reverse transcription polymerase chain reaction (RT-PCR). Expression of IL-13 mRNA in renal tissue was studied by in situ hybridization (ISH) techniques. RESULTS: The level of IL-13 in plasma and the expression of IL-13 mRNA in PBMCs were significantly higher in LN patients than those in the controls (P < 0.001). Increased expression of IL-13 mRNA was detected in renal tissue of active LN patients compared to those in the controls (P < 0.001). Analysis of the linear correlation indicated that the level of IL-13 mRNA in the tubulointerstitial area in patients with active LN correlated with the concentration of serum creatinine (Scr), the glomerular activity index (GAI), the activity index of tubulointerstitium, and the level of serum C3 (P < 0.05 for each). CONCLUSION: The elevation of IL-13 may play an important role in the molecular pathogenesis of active LN.

Adult↗
PubMed2001

[The resource conservation and utilization of wild Sika deer in China].

There had once been six subspecies of Sika deer (Cervus nippon) in China, but now only three subspecies in wild, i.e. Northeast China, Sichuan and South China subspecies, and all the three subspecies lie in the endangered status. Most of population are very small, and their distribution ranges have already been broken up into many isolated patches, furthermore, their habitats have been deteriorating. So it is very necessary to enhance the protecting of wild sika deer. Some endangered and small populations of wild deer can be saved by inflows of domestic health deer. Wild deer can help farm deer to acquire some good characters again by interbreeding between them. So we think that the purposes of protecting wild population and developing domestic population can be achieved by cooperating between reserves and deer farms.

Animals↗
PubMed2001

Gene-CYP11B2 expression in rat liver in hepatic fibrogenesis induced by CCl4.

OBJECTIVE: To identify aldosterone synthase gene-CYP11B2 mRNA expression in normal and fibrotic liver in rats and evaluate the curative effect of antisterone. METHODS: 160 Wistar rats weighing about 250 g were divided into 4 groups. In the model group (n = 40), the rats were injected with 40% CCl4 (0.25 ml/100 g) subcutaneously three times a week. In the antisterone group (n = 40), the rats were injected with 40% CCl4 (0.25 ml/100 g) subcutaneously three times a week. Antisterone equivalent to 20 mg.kg-1.d-1 was given intragastrically (ig). In the malotilate group (n = 40), the rats were injected with 40% CCl4 (0.25 ml/100 g) subcutaneously three times a week. Malotilate equivalent to 50 mg/kg-1.d-1 was given ig. In the control group (n = 40), the rats were injected with olive oil only. After 2, 4, 6, 8 and 10 weeks, animals were sacrificed, and morphological examination was carried out. The area of collagen was examined with an Image Analyse System. Expression of the aldosterone synthase gene, CYP11B2 mRNA, in fibrotic and normal liver was detected by means of reverse transcriptase polymerase chain reaction (RT-PCR) and in situ hybridization. RESULTS: In situ hybridization and RT-PCR showed that the expression of CYP11B2 mRNA, which localized in the endoplasm of hepatic stellate cells (HSCs), was up regulated when fibrogenesis occurred. Histological observation indicated that the grade of fibrosis and the area of collagen in the antisterone group were less than those in model group before 6 weeks (P < 0.05). There was no significant difference between the antisterone and malotilate groups (P > 0.05). After that, however, the grade of fibrosis and the area of collagen in the antisterone group were higher than those in the malotilate group (P < 0.05). There was no significant difference between the antisterone and model groups (P > 0.05). CONCLUSIONS: The expression of CYP11B2 mRNA is up regulated in fibrotic liver. Antisterone can have a partial fibrogenesis-inhibiting effect in the early stages.

Animals↗
PubMed2001

[A study on mechanism for cytotoxicity of nitrobenzene to hepatocarcinoma cell line].

OBJECTIVE: To study the mechanism for cytotoxicity of nitrobenzene to hepatocarcinoma cell line. METHODS: Cytotoxicity was determined with MTT assay in SMMC-7721 cell strain, human hepatocarcinoma cell, incubated with nitrobenzene at varied concentrations in vitro for 24 hours. The effect of an agent to clear reactive oxygen on protection from cell death was observed. Cell cycle of hepatocytes was also observed using flow cytometry and their DNA damage was detected with single-cell gel electrophoresis assay. RESULTS: Nitrobenzene at concentration of 8 mmol/L or over could induce death of hepatocytes obviously with a survival rate of less than 82%, and addition of superoxide dismutase, hydrogen peroxidase or mannitol to the incubation media could inhibit its cytotoxicity partly, with survival rates of 93.7%, 96.6% and 93.2%, respectively. Nitrobenzene could affect cell cycle of hepatocytes, showing a decreased fraction of G(1) phase and increased fraction of S and G(2)/M phase, but could not induce DNA strand breaks in them. CONCLUSIONS: Nitrobenzene had cytotoxicity to hepatocytes cultured in vitro, in which reactive oxygen species may play a certain role. Nitrobenzene was a non-genotoxicant and could cause cancer by promotion of cell proliferation.

Cell Cycle↗
PubMed2001

[Enantioseparation of twelve pharmaceutical racemates with high performance capillary electrophoresis using L-leucine as chiral selector].

A rapid enantiomeric separation method using L-leucine as chiral selector was established. Capillary zone electrophoresis (CZE) has been used for the enantiomeric separation of twelve pharmaceutical racemates with bare fused silica capillary and employing L-leucine as chiral selector. The enantiomeric resolution was influenced by L-leucine concentration and pH of background electrolyte (BGE). The effects of the BGE types and concentrations on the enantiomeric separation were also investigated. The results showed that in the solution containing 50 mmol/L borax and 70 mmol/L L-leucine (pH 9.0), all the twelve drugs were on baseline separated in less than 11 minutes.

Electrophoresis, Capillary↗
PubMed2001

[Effect of the Purariae-isofiavones on atrophic nasal mucosas in ovariectomized rats].

OBJECTIVE: To study the effect of Purariae-isoflavone on atrophic nasal mucosas in ovariectomized rats. METHOD: 60 rats were divided into four groups randomly, every group with 15 rats. The first group was studied as normal control group. Rats of the second group were ovariectomized and not given any treatment. Rats of the third group were given Weinian by gastrogavage from 30 days after being ovariectomized to being killed. Rats of the forth group were given purariae isoflavone by gastrogavage from 30 days after operation to being killed. Level of Estrodiol (E2) of every rat was measured. Morphological changes of the nasal mucosas were observed by light-microscopy and electron-microscopy. RESULT: 30 days after being ovariectomized, atrophic nasal mucosas occured, and average E2 level was lower significantly than that of control group (P < 0.05). Atrophic mucosas recovered after being treated with Weinian or Purariae isoflavone. E2 level of the third group was lower significantly than that of the first group and the second group (P < 0.05). E2 level of the forth group recovered (P > 0.05). CONCLUSION: Purariae-isoflavone have effects on treating the atrophic nasal mucosas and recovering E2 level in ovariectomized rats.

Animals↗