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Biomedical subjects

Wei Zhang

Publications and source records attributed to Wei Zhang.

At least 343 records · Page 19Linked to original sources
PubMed2006

[Establishment of method for cytochrome P450 of earthworms (Eisenia fetida) as a biomarker].

Earthworm (Eisenia fetida) was chosen as test soil fauna to establish the method for determination of cytochrome P450 content. By means of thoroughly washing with salt solution, changing centrifugal acceleration and dissolving microsomal membranes of earthworms with sodium cholate, the determination of cytochrome P450 was performed. Base on the method, dynamic relationships of dose-response for cytochrome P450 contents in earthworm and phenanthrene concentrations were conducted by contact filter paper and soil contaminated with phenanthrene. Results indicate that cytochrome P450 are covered up by interferential material in earthworm, which makes the classic peak lag and appear at 455 - 457nm in the CO difference spectrum with a spectrophotometer. Through increasing centrifugal acceleration and adding reagent of solubilization, the interference is removed mostly and the classic peak of P450 returns to appear at 450nm +/- 1nm. The exposure tests of phenanthrene with contact filter paper (10(-6), 10(-5), 10(-4), 10(-3) and 10(-2) mg x mL(-1)) and soil (1, 2, 4 and 8 mg x kg(-1)) reveal that the dose-response relationships exist between the pollutant and cytochrome P450. Soil tests of different exposure durations (1, 3, 7, 14 and 28d) show the effects of different phenanthrene concentration on earthworm cytochrome P450 contents are to activate (7d) and to inhibit (14d and 28d), and the content of P450 is 0.99 - 1.41 and 0.77 - 0.88 (p < 0.05) times of control respectively. From this study, cytochrome P450 content of earthworm has the merit of simpleness, speediness and economy for determination, and it could be used as a sensitive biomarker for monitoring the exposure of sublethal pollution in terrestrial ecosystem.

Animals↗
PubMed2006

[Soil-based eco-toxicity of petroleum to terrestrial higher plant after phytoremediation].

Petroleum-contaminated soil after five-year phytoremediation was taken as tested soil initially spiked with a serial diesel concentration of 5 000, 15 000 and 30 000 mg/kg (dry weight). Residual concentrations of mineral oil by chemical analysis of gravimetry, as well as the soil-based eco-toxicity to wheat (Triticum aestivum L.), the terrestrial higher plant by several ecotoxicological bioassays including seed germination and root elongation test, early seedling growth test, contents of cytochrome P450 monooxygenases, activities of antioxidant enzymes (superoxide dismutase, SOD, and peroxidase, POD), and lipid peroxide (malondialdehyde, MDA content in wheat seedling leaves, etc. were evaluated. Results showed that mineral oil was well removed in each treatment by chemical analysis, with residual concentrations ranging from 199 to 877 mg/kg (dry weight) and with total removal rates between 90.1% and 97.2%. The evaluating results by eco-toxicological assays differed to some extent from those by chemical analysis, meanwhile, eco-toxicity of each treatment differed depending on endpoints by different bioassays. Among the ecotoxicological indexes, root length (48 h), root fresh weight (7 d), contents of P450, activities of SOD, and contents of MDA, etc. exhibited better indication to the soil toxicity. The general evaluation by combining the two analyses chemical and eco-toxicological indicated that the ecological risk was higher in most intermediately- and heavily-contaminated treatments (initially spiked with diesel concentration of 15,000 mg/kg and 30,000 mg/kg).

Ecology↗
PubMed2006

[Expression of glutathione-S-transferase fusion protein and human CCL3L1 protein].

OBJECTIVE: To clone human CCL3L1 cDNA and to express and purify the glutathione-S-transferase (GST) fusion protein and human CCL3L1 protein. METHODS: Total RNA was isolated from breast cancer cell line MCF7. CCL3L1 cDNA including open reading frame was obtained by RT-PCR. PCR product was digested with EcoR I and cloned into the pGEX-4T-1 vector. The plasmids from positive clone was prepared and sequenced to confirm the CCL3L1 in correct fusion form. pGEX-4T-CCL3L1 was transfected to BL21 E. coli via isopropyl-beta-D-thiogalactoside (IPTG) induction to produce GST-CCL3L1 fusion protein, which was further detected by SDS-PAGE and Western blotting. RESULTS: As shown and confirmed by restriction endonuclease digestion analysis, CCL3L1 was correctly inserted into pGEX-4T-1 vector. The expressed fusion protein had a relative molecular weight of approximately 34 kD. CONCLUSION: GST-CCL3L1 fusion protein can be successfully expressed using appropriate vector.

Cell Line, Tumor↗
PubMed2006

[Apoptosis in male germ cells induced by testicular denervation].

OBJECTIVE: To evaluate the role of spermatic nerves in the regulation of spermatogenesis. METHODS: Fifty-four mature SD male rats (350-375 g) were randomized into a sham operation group (SO) and three experiment groups, and the latter underwent bilateral surgical removal of the superior spermatic nerve (SSN) or/and the inferior spermatic nerve (ISN). The animals were killed 1 month and 2 months after the operation. HE stain was used to observe spermatogenesis. Transmission electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) were employed to detect apoptosis. RESULTS: Impaired spermatogenesis was observed 2 months after the operation, with only Sertoli cells and a few spermatogonia remaining in the regressed tubules in all the treatment groups. The abnormal tubules in the SSN, ISN and SSN + ISN denervated testes accounted for (13.25 +/- 2.03)%, (11.0 +/- 4.36)% and (34.17 +/- 3.78)% respectively. Chromosome condensation and fragmentation in the germ cells were observed under the electron transmission microscope in all the denervated testes. TUNEL showed the spermatogonia and Leydig cells to be apoptotic in all the denervated testes and the incidence of the apoptotic cells in the SSN + ISN denervated testes was significantly higher than in the SSN or ISN denervated ones. CONCLUSION: Spermatic nerves play an important role in spermatogenesis.

Animals↗
PubMed2006

[Antisperm-antibodies induced by testicular torsion and its influence on testicular function].

OBJECTIVE: To investigate the changes of antisperm antibodies (AsAb), sexual hormones, and inhibin B (INH B) in patients before and after testicular torsion, as well as the effects of these factors on testicular function and reproduction. METHODS: Ten patients with single acute testicular torsion (left side 9 and right side 1), aged 16-45 years (19.6 on average), disease course of 3-6 days (averaging 4.7 days), underwent surgical removal of the damaged testis. Before and after the operation, serum AsAb (IgG, IgM, IgA) and INH B were measured by ELISA, and serum follicle-stimulating hormone (FSH), luteotropic hormone (LH), and testosterone (T) determined by chemoluminescence autoanalyzer. RESULTS: After the operation, the AsAb levels rose significantly and remained high for at least 26 weeks. The level of INH B was the lowest in the 3rd week and restored to normal in the 12th week, with significant difference between preoperation and the 3rd or the 6th week after the operation. The levels of LH and INH B in the 26th week were elevated significantly compared with the 6th. CONCLUSION: Testicular injury induced the elevation of AsAb, which would last a very long time. The change of INH B was closely related with the injury of the testis, which reflected the degree of testicular injury and functional restoration of the patients after the operation. Our study showed that AsAb and INH B can be used as useful tools for monitoring testicular function and reproduction.

Adolescent↗
PubMed2006

[Alcohol consumption and drug use among middle school students aged 13-15 in 4 cities of China].

OBJECTIVE: To provide data on alcohol consumption and drug use among middle-school students aged 13-15 in 4 cities of China, and to provide evidence for developing intervention strategies on adolescents alcohol and drug use. METHODS: Standardized sample selection process of two-stage cluster-sampling was used in middle-school students in Beijing, Hangzhou, Wuhan and Urumchi. A self-administered questionnaire survey was conducted in Sept. 2003 and data was analyzed by Epi Info software. RESULTS: Among 7344 students from grade 1 to 3, 36.5% had tasted while 14.4% had drunk alcohol in the past 30 days. 9.9% had experienced drunkness, 5.1% had been in trouble because of drinking, and 1.6% had ever used illegal drugs. Significant differences had been found in all the cities. Higher graders, older students and boys had higher rates of alcohol and addictive drug use than low graders, younger students and girls. 51.9% had been taught on take alcohol safety and another 27.6% on skills of rejecting alcohol, during the past school year. CONCLUSIONS: The current situation of alcohol and addictive drug use among Chinese middle-school students aged 13-15 seemed to be quite critical, suggesting that it is necessary to carry out relevant health education in accordance with different characteristics in area, gender and age of the students.

Adolescent↗
PubMed2006

[Inhibitory effects of RNA interference on expression of matrix metalloproteinase-9 gene and invasiveness and adhesion in ovarian cancer cells].

OBJECTIVE: To investigate the inhibitory effects of RNA interference (RNAi) on the expression of matrix metalloproteinase-9 (MMP-9) gene and invasiveness and adhesion of ovarian cancer cells. METHODS: Four groups of different specific target sequence in coding region of MMP-9 and one non-specific sequence were chosen, which were Site1, Site2, Site3, Site4 and Site5. Small interference RNA (siRNA) expression cassettes (SEC) were constructed by PCR and transfected into ovarian cancer HO-8910PM cells. RT-PCR and western blot were used to detect mRNA and protein expression of MMP-9 gene; the abilities of invasion and adhesion were detected by Matrigel invasion assay and cell adhesion assay. RESULTS: The expression of MMP-9 was inhibited and the inhibitory effects of different sequence were varied. The mRNA expression was 0.64 +/- 0.06, 0.47 +/- 0.07, 0.55 +/- 0.10 in Site1, Site2, Site3 group, and protein expression was 0.30 +/- 0.09, 0.27 +/- 0.08, 0.37 +/- 0.12, respectively. Site2 group had the most efficient inhibitory effect, followed by Site1 and Site3 groups. Cell growth curve revealed that cell growth was significantly inhibited in Site2 group. Invasiveness and adhesion were significantly reduced, the inhibitory rate on invasion in Site1, Site2, Site3 groups were 50.0%, 50.0% and 37.5%, respectively; the inhibitory rate on adhesion in Site1, Site2, Site3, Site4 groups were 43.8%, 48.8%, 33.9%, 24.2% at 60 min and 41.6%, 40.2%, 35.1%, 16.0% at 90 min, respectively. CONCLUSIONS: RNAi exists in ovarian HO-8910PM cells. MMP-9 siRNA can specifically down-regulate MMP-9 expression and lead to the inhibition of invasiveness and adhesion in ovarian cancer cells.

Blotting, Western↗
PubMed2006

[Effects of drug cupping therapy on immune function in chronic asthmatic bronchitis patients during protracted period].

UNLABELLED: To observe the clinical effect of drug cupping therapy (DCT, cupping therapy with pingchuan ointment made by the authors themselves in the cups) on chronic asthmatic bronchitis (CAB) during the protracted period, and explore its effect on immune function. METHODS: Seventy-seven patients were randomly divided into two groups:the treated group (n=40) treated by orally taken Liuwei Dihuang Pill (LDP) and DCT and the control group (n=37) with LDP and common cupping therapy without drug in cups. The changes of T-lymphocyte subset, levels of interferon-gamma (IFN-gamma), interleukin (IL), immunoglobulin (Ig), complement 3 and 4 (C3 and C4) were detected before and after treatment. RESULTS: The total effective rate was higher in the treated group than that in the control group (90.0% vs. 59.5%, P < 0.01). The levels of CD4+, CD4+ /CD8+, IL-2, IFN-gamma, C3, C4, IgA, IgG and IgM increased, while the levels of IgE, IL-4, IL-10 and CD8+ decreased after treatment in both groups (P < 0.05 or P < 0.01), the improvements were better in the treated group than that in the control group (P < 0.05). CONCLUSION: DCT shows better curative effects than that of common cupping therapy without drug, it could improve the cellular and humoral immunity in CAB patients.

Adolescent↗
PubMed2006

[Sequence analysis of HLA-B*4061 allele newly found].

The aim of this study was aimed to investigate the molecular genetic basis for a novel HLA allele, HLA-B*4061, in Chinese population. DNA was extracted from whole blood by salting-out method. The HLA-B exons 1 - 8 of the proband was amplified and the amplified product was cloned using TOPO TA cloning sequencing kit to split the two alleles apart. Both strands of exons 2, 3 and 4 of chosen colonies were sequencing. The PCR-SSP was performed to confirm the mutations detected by sequencing. The sequencing results showed HLA-B alleles of the proband as B*4601 and the novel allele. The sequences of the novel allele have been submitted to GenBank (DQ089628, DQ089629, DQ089630). After HLA blast analysis, the novel allele showed a single nucleotide mismatch with B*400101 in exon 2 at position 272 C-->A, as the results, changing amino acid from Ser to Tyr at codon 67. It is concluded that this allele is a novel one and has been officially named B*4061 by the WHO Nomenclature Committee.

Alleles↗
PubMed2006

[Risk factors for cardiovascular autonomic neuropathy and their prognostic implications in type 2 diabetes mellitus].

OBJECTIVE: Risk factors for diabetic cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes were analyzed to establish a regression model for evaluating the diagnosis of CAN. METHODS: 325 patients with type 2 diabetes were divided into four groups according to the results of four standard function tests. Every patient was required to offer detailed disease history and accept physical examination, serum and urine tests and examinations including ECG, nerve conduction velocity, retinoscope and Doppler of carotid and lower limb arteries. RESULTS: 64.0% of the patients had abnormal autonomic function and 30.2% definite CAN. There was significant difference among groups about age, average glycosylated forms of hemoglobin (HbA1c), systolic blood pressure, corrected 24 h albumin excretion and heart rate at rest (P < 0.001). The incidence of diabetic complications and accompanying diseases increased with deterioration of CAN (P < 0.05). The regression model showed that age, average HbA1c, hypertension, peripheral neuropathy, retinopathy, tachycardia at rest and duration of peripheral neuropathy were significant related factors for CAN. With these factors, a mathematic formula was established which could be used for evaluating the diagnosis of CAN. CONCLUSION: Except for age and hypertension, risk factors were all induced by hyperglycemia. It is suggested that control of hyperglycemia is of primary importance in preventing diabetic complications.

Adult↗
PubMed2005

Selective loss of fine tuning of Gq/11 signaling by RGS2 protein exacerbates cardiomyocyte hypertrophy.

Alterations in cardiac G protein-mediated signaling, most prominently G(q/11) signaling, are centrally involved in hypertrophy and heart failure development. Several RGS proteins that can act as negative regulators of G protein signaling are expressed in the heart, but their functional roles are still poorly understood. RGS expression changes have been described in hypertrophic and failing hearts. In this study, we report a marked decrease in RGS2 (but not other major cardiac RGS proteins (RGS3-RGS5)) that occurs prior to hypertrophy development in different models with enhanced G(q/11) signaling (transgenic expression of activated Galpha(q)(*) and pressure overload due to aortic constriction). To assess functional consequences of selective down-regulation of endogenous RGS2, we identified targeting sequences for effective RGS2 RNA interference and used lipid-based transfection to achieve uptake of fluorescently labeled RGS2 small interfering RNA in >90% of neonatal and adult ventricular myocytes. Endogenous RGS2 expression was dose-dependently suppressed (up to 90%) with no major change in RGS3-RGS5. RGS2 knockdown increased phenylephrine- and endothelin-1-induced phospholipase Cbeta stimulation in both cell types and exacerbated the hypertrophic effect (increase in cell size and radiolabeled protein) in neonatal myocytes, with no major change in G(q/11)-mediated ERK1/2, p38, or JNK activation. Taken together, this study demonstrates that endogenous RGS2 exerts functionally important inhibitory restraint on G(q/11)-mediated phospholipase Cbeta activation and hypertrophy in ventricular myocytes. Our findings point toward a potential pathophysiological role of loss of fine tuning due to selective RGS2 down-regulation in G(q/11)-mediated remodeling. Furthermore, this study shows the feasibility of effective RNA interference in cardiomyocytes using lipid-based small interfering RNA transfection.

Animals↗
PubMed2005

[Diffuse muscular calcification with subcutaneous cysts].

OBJECTIVE: Diffuse muscular calcification was rare myopathological change due to abnormal metabolism of calcium, which was mainly found in dermatomyositis and myositis ossificans progressiva. Here we reported a case of diffuse muscular calcification that clinically mimicked myositis ossificans progressiva. The disease might be a new type of congenital calcium metabolic disease. METHODS: A 15-year-old girl developed subcutaneous cysts in the wrist and ankle when she was 1 year old. At the age of 9, she developed recurrent fever with myalgia, fatigue and diffuse muscular calcification. It was difficult for her to squat, run or walk. Protuberance presented in the subcutaneous tissue of her trunk. Some nodules ruptured with outflow of chalky material. ESR, ENA, RF, CRP, PTH, CK were in normal limits. EMG was unremarkable. X-ray confirmed diffuse calcification in the muscle and subcutaneous tissues. Biceps muscle biopsy was performed. RESULTS: Numerous inflammatory cells infiltrated around vessels in the perimyosium with perifascicular muscle fiber atrophy and degeneration. Many RRF and SDH positive fibers were also observed. EM showed tubular reticular inclusions in vascular endothelium. CONCLUSION: Diffuse muscular calcification indicated existence of systemic calcium metabolic abnormality. As the clinical symptoms and distribution pattern of calcification were different from dermatomyositis with subcutaneous calcification and myositis ossificans progressiva, our case might be a new type of disease. The microvascular changes might result in the lesion of muscle fibers.

Adolescent↗
PubMed2005

Analysis of angiogenesis using in vitro experiments and stochastic growth models.

The global properties of vascular networks grown with an in vitro angiogenesis assay are compared quantitatively, using automated image analysis, with the global properties of networks obtained with discrete, stochastic growth models. The model classes that are investigated are invasion percolation and diffusion limited aggregation. By matching global properties to experimental data, one can infer which model classes and parameters are most reflective of angiogenesis in experimental cells. This sheds light on large-scale emergent properties of angiogenesis from a systems perspective. It is found that invasion percolation is better than diffusion limited aggregation at matching experimental data. We also present evidence that the distribution of the lengths of real tubule complexes follows a power law.

Animals↗
PubMed2005

Characterization of transferrin receptor-dependent GaC-Tf-FeN transport in human leukemic HL60 cells.

BACKGROUND: Understanding the uptake of GaC-Tf-FeN by cells will provide key insights into studies on transferrin-mediated drug delivery. METHODS: The mechanism of GaC-Tf-FeN transporting into and out of HL60 cells has been investigated by comparing transports between GaC-Tf-FeN and apoTf by means of 125I-labeled transferrin. RESULTS: An association constant for GaC-Tf-FeN was 2 times that for apoTf. GaC-Tf-FeN and apoTf of cell surface-bound displayed similar kinetics during the uptake, but the release rates of internalized GaC-Tf-FeN and apoTf from cells were different which showed characteristic disparate. The release continued to occur during the incubation of GaC-Tf-FeN in the presence of nonradioactive apoTf. Neither NaN3 nor NH4Cl could completely block internalization of GaC-Tf-FeN, but they prevented the release of GaC-Tf-FeN from the cells. Excess cold unlabeled apoTf could overcome the block in the release due to NH4Cl but not NaN3. The binding and internalization of GaC-Tf-FeN could be competitively inhibited by nonradioactive apoTf. It implies that both bind to the same receptor on the membrane and the localization of GaC-Tf-FeN resembles that of apoTf inside cells. Pretreated cells with pronase abolished the binding of GaC-Tf-FeN significantly. CONCLUSION: On the basis of these findings, we proposed the "transferrin receptor" for the mechanism of GaC-Tf-FeN transport by HL60 cells.

Ammonium Chloride↗
PubMed2005

The co-chaperone p23 arrests the Hsp90 ATPase cycle to trap client proteins.

The action of the molecular chaperone Hsp90 is essential for the activation and assembly of an increasing number of client proteins. This function of Hsp90 has been proposed to be governed by conformational changes driven by ATP binding and hydrolysis. Association of co-chaperones and client proteins regulate the ATPase activity of Hsp90. Here, we have examined the inhibition of the ATPase activity of human Hsp90beta by one such co-chaperone, human p23. We demonstrate that human p23 interacts with Hsp90 in both the absence and presence of nucleotide with a higher affinity in the presence of the ATP analogue AMP-PNP. This is consistent with an analysis of the effect of p23 on the steady-state kinetics that revealed a mixed mechanism of inhibition. Mass spectrometry of the intact Hsp90.p23 complex determined the stoichiometry of binding to be one p23 to each subunit of the Hsp90 dimer. p23 was also shown to interact with a monomeric, truncated fragment of Hsp90, lacking the C-terminal homodimerisation domain, indicating dimerisation of Hsp90 is not a prerequisite for association with p23. Complex formation between Hsp90 and p23 increased the apparent affinity of Hsp90 for AMP-PNP and completely inhibited the ATPase activity. We propose a model where the role of p23 is to lock individual subunits of Hsp90 in an ATP-dependent conformational state that has a high affinity for client proteins.

Adenosine Triphosphatases↗
PubMed2005

Tiagabine for posttraumatic stress disorder: effects of open-label and double-blind discontinuation treatment.

RATIONALE: Preliminary results suggest a potential benefit of agents that enhance gamma-aminobutyric acid (GABA) neurotransmission in treating posttraumatic stress disorder (PTSD). OBJECTIVES: It is the aim of this study to evaluate the effect of a selective GABA reuptake inhibitor (SGRI), tiagabine, in patients with PTSD. METHODS: Twenty-nine adult outpatients with PTSD were treated with open-label tiagabine for 12 weeks. Those who responded to treatment (i.e., demonstrated at least minimal clinical improvement) were randomly assigned to double-blind treatment with either tiagabine or matching placebo. Efficacy assessments included measures of PTSD, anxiety, depression, sleep quality, resilience, and disability. Safety evaluation included changes in vital signs and weight and treatment-emergent adverse events. RESULTS: In subjects completing open-label treatment (n=19), significant improvement was observed on all outcome measures (P<0.05) and the treatment was well tolerated. Eighteen subjects responded and were randomized into the double-blind phase. Following randomization, benefits of treatment were generally upheld, but there was no greater incidence of relapse in the placebo group. However, continued treatment with tiagabine was associated with a greater trend toward likelihood of remission than if one was switched to placebo (P<0.08). CONCLUSIONS: These findings suggest a possible role for the SGRI tiagabine in the treatment of PTSD. As the role of GABAergic drugs in PTSD is poorly defined, larger, randomized, double-blind, placebo-controlled trials are needed.

Adult↗