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Hong Wei

Publications and source records attributed to Hong Wei.

At least 19 recordsLinked to original sources
PubMed2006

Spinal and pontine alpha2-adrenoceptors have opposite effects on pain-related behavior in the neuropathic rat.

Descending noradrenergic pathways contribute to feedback inhibition of pain by releasing norepinephrine in the spinal cord. Noradrenergic nuclei in the pons contain abundant alpha(2)-adrenoceptors. We assessed the contribution of pontine alpha(2)-adrenoceptors to endogenous regulation of pain in nerve-injured rats. Tactile allodynia and mechanical hyperalgesia were assessed in the injured dermatome and heat nociception in an uninjured dermatome. Atipamezole, an alpha(2)-adrenoceptor antagonist, or saline was administered systemically or microinjected into the locus coeruleus, the lateral parabrachial nucleus, the central nucleus of the amygdala, the midbrain periaqueductal gray, and/or through an intrathecal (i.t.) catheter to the spinal cord. Atipamezole administered systemically, into the amygdala or the periaqueductal gray had no significant effects on pain behavior. Atipamezole (0.3-5 microg) microinjected into the pons, the locus coeruleus or the lateral parabrachial nucleus, produced a selective and dose-related antiallodynia, which was reversed by i.t. administration of atipamezole (5 microg). I.t. administration of atipamezole alone (5 microg) produced thermal hypersensitivity in the non-neuropathic segment (tail) of nerve-injured animals. In sham-operated controls, i.t. administration of atipamezole had no effect. Suppression of heat nociception in uninjured dermatomes of nerve-injured but not the control animals following i.t. administration of atipamezole indicates that nerve injury produced a tonic activation of noradrenergic feedback inhibition acting on spinal alpha(2)-adrenoceptors. In parallel, antiallodynia induced by pontine administration of atipamezole indicates that nerve injury induces a tonic activation of pontine alpha(2)-adrenoceptors that promotes neuropathic hypersensitivity by attenuating descending inhibition. Thus, spinal and pontine alpha(2)-adrenoceptors have opposite effects on pain-related behavior in neuropathic animals.

Adrenergic alpha-Antagonists↗
PubMed2006

5-HT(1A) receptors in endogenous regulation of neuropathic hypersensitivity in the rat.

The role of medullary and spinal 5-HT(1A) receptors in endogenous regulation of neuropathic hypersensitivity was studied. When administered in the rostroventromedial medulla or subcutaneously, WAY-100635, a 5-HT(1A) receptor antagonist, attenuated mechanical hypersensitivity in rats with a spinal nerve injury. Thermal or mechanical nociception outside of the injured area was not influenced by medial medullary or subcutaneous administration of WAY-100635. Intrathecal administration of WAY-100635 had no significant effect on pain-related behavior. Suppression of mechanical hypersensitivity induced by medial medullary administration of WAY-100635 was reversed by intrathecal administration of WAY-100635 or atipamezole, an alpha2-adrenoceptor antagonist, but not by naloxone, an opioid receptor antagonist. The results indicate that endogenous release of 5-HT, via action on medial medullary 5-HT(1A) receptors, tonically suppresses descending inhibition in neuropathic animals. Following medial medullary administration of a 5-HT(1A) receptor antagonist, descending pain regulatory pathways are disinhibited. This leads to selective attenuation of neuropathic hypersensitivity, due to action on spinal 5-HT(1A) receptors and alpha2-adrenoceptors.

Adrenergic alpha-Antagonists↗
PubMed2006

Efficacy of subcutaneous administration of gonadotropin-releasing hormone agonist on idiopathic central precocious puberty.

In order to assess the feasibility of subcutaneous administration of Triptorelin with 6-week intervals for the suppression of pituitary-gonadal axis and changes of clinical signs in girls with idiopathic central precocious puberty (ICPP), 46 girls with ICPP were treated with GnRHa. Triptorelin (Decapeptyl, 3.75 mg) was administered subcutaneously (SC) at 6-weeks intervals or intramuscularly (IM) at 4-weeks intervals randomly for more than 12 months consecutively. During GnRHa therapy, clinical parameters and laboratory data, including height, weight, pubertal stage, bone age, uterine volume and ovarian size, serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and estradiol (E2), were monitored and analyzed. It was found that both treatment regimes led to regression of precocious puberty and reversal of secondary sexual characteristics. Breast developments regressed. Uterine volume was decreased after treatment, but there was no statistically significant difference. Mean ovarian volume did not change significantly during treatment. The height velocity was decreased significantly from 6.3+/-1.4 cm/year to 5.8+/-1.2 cm/year in group SC and 6.7+/-1.3 cm/year to 5.4+/-1.0 cm/year in group IM, respectively. The rate of bone maturation was reduced significantly during treatment. The ratio of deltaBA/deltaCA was 1.2+/-0.2 or 1.3+/-0.3 at the onset of therapy and decreased significantly after the treatment to 0.7+/-0.2 or 0.9+/-0.1, respectively. The predicted adult height was increased significantly and progressively during therapy. The levels of serum LH, FSH and E2 returned to the prepubertal condition. No significant side effects of therapy were noted. The most common side effect during SC treatment was that a non-irritating, 1 cm in diameter mass was palpated at the site of subcutaneous injection in the abdominal wall of patients, which disappeared after 6-12 weeks. Two girls had minimal withdrawal vaginal bleeding episodes after the first injection. It was concluded that both IM and SC triptorelin administrations were clinically effective. They induce profound suppression of hypothalamic-pituitary-gonadal axis while stabilizing height velocity, slowing bone maturation and increasing predicted adult height. These results suggest that subcutaneous injection of triptorelin in 6-weeks intervals at a dosage of 3.75 mg be a safe and acceptable regimen for ICPP

Bone Development↗
PubMed2006

The role of thickness transitions in convective assembly.

Here we examine the microscopic details of convective assembly, a process in which thin colloidal crystals are deposited on a substrate from suspensions of nearly monodisperse spheres. Previously, such crystals have been shown to exhibit a strong tendency toward the face-centered cubic structure, which is difficult to explain on thermodynamic grounds. Using real-time microscopic visualization, electron microscopy, and scanning confocal microscopy, we obtain clues about the crystallization mechanism. Our results indicate that the regions at which a growing crystal transitions from n to n + 1 layers can play an important and previously unrecognized role in the crystallization. For thin crystals, we show both from experiment and through simple modeling that these transition regions can generate specific crystal structures. In thicker crystals, the crystallization is more complicated, but the transition regions must still be considered before a complete understanding of convective assembly can be obtained.

Colloids↗
PubMed2006

Stable skin-specific overexpression of human CTLA4-Ig in transgenic mice through seven generations.

Skin graft rejection is a typical cellular immune response, mainly mediated by T cells. Cytotoxic T lymphocyte associated antigen 4-immunoglobin (CTLA4-Ig) extends graft survival by blocking the T cell co-stimulation pathway and inhibiting T cell activation. To investigate the efficacy of CTLA4-Ig in prolonging skin graft survival, human CTLA4-Ig (hCTLA4-Ig) was engineered to overexpress in mouse skin by transgenesis using the K14 promoter. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot assay indicated that the expression of CTLA4-Ig remained skin-specific and relatively constant compared to the internal control protein, AKT, through seven generations. The presence and concentration of the hCTLA4-Ig protein in transgenic mouse sera was determined by enzyme-linked immunosorbent assay (ELISA), and the results indicated that the serum CTLA4-Ig concentration also remained constant through generations. Survival of transgenic mouse skins grafted onto rat wounds was remarkably prolonged compared to that of wild-type skins from the same mouse strain, and remained comparable among all seven generations. This suggested that the bioactive hCTLA4-Ig protein was stably expressed in transgenical mice through at least seven generations, which was consistent with the stable skin-specific CTLA4-Ig expression. The results demonstrated that the transgenic expression of hCTLA4-Ig in skin driven by the K14 promoter remained constant through generations, and a transgenic line can be established to provide transgenic skin with extended survival reproducibly.

Abatacept↗
PubMed2006

Topotecan is a substrate for multidrug resistance associated protein 4.

Topotecan (TPT) is a semisynthetic water-soluble derivative of camptothecin (CPT) used as second-line therapy in patients with metastatic ovarian carcinoma, small cell lung cancer, and other malignancies. However, both dose-limiting toxicity and tumor resistance hinder the clinical use of TPT. The mechanisms for resistance to TPT are not fully defined, but increased efflux of the drug by multiple drug transporters including P-glycoprotein (PgP), multidrug resistance associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) from tumor cells has been highly implicated. This study aimed to investigate whether overexpression of human MRP4 rendered resistance to TPT by examining the cytotoxicity profiles using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide (MTT) assay and cellular accumulation of TPT in HepG2 cells stably overexpressing MRP4. Two kinds of cell lines, HepG2 with insertion of an empty vector plasmid (V/HepG2), HepG2 cells stably expressing MRP4 (MRP4/HepG2), were exposed to TPT for 4 or 48 hr in the absence or presence of various MRP4 inhibitors including DL-buthionine-(S,R)-sulphoximine (BSO), diclofenac, celecoxib, or MK-571. The intracellular accumulation of TPT and paclitaxel (a PgP substrate) by V/HepG2 and MRP4/HepG2 cells was determined by incubation of TPT with the cells and the amounts of the drug in cells were determined by validated HPLC methods. The study demonstrated that MRP4 conferred a 12.03- and 6.86-fold resistance to TPT in the 4- and 48-hr drug-exposure MTT assay, respectively. BSO, MK-571, celecoxib, or diclofenac sensitised MRP4/HepG2 cells to TPT cytotoxicity and partially reversed MRP4-mediated resistance to TPT. In addition, the accumulation of TPT was significantly reduced in MRP4/HepG2 cells compared to V/HepG2 cells, and one-binding site model was found the best fit for the MRP4-mediated efflux of TPT, with an estimated K(m) of 1.66 microM and V(max) of 0.341 ng/min/106 cells. Preincubation of MRP4/HepG2 cells with BSO (200 microM) for 24 hr, celecoxib (50 microM), or MK-571 (100 microM) for 2 hr significantly increased the accumulation of TPT over 10 min in MRP4/HepG2 cells by 28.0%, 37.3% and 32.5% (P < 0.05), respectively. By contrast, there was no significant difference in intracellular accumulation of paclitaxel in V/HepG2 and MRP4/HepG2 cells over 120 min. MRP4 also rendered resistance to adefovir dipivoxil (bis-POM-PMEA) and methotrexate, two reported MRP4 substrates. MRP4 did not exhibit any significant resistance to other model drugs including vinblastine, vincristine, etoposide, carboplatin, cyclosporine and paclitaxel in both long (48 hr) and short (4 hr) drug-exposure MTT assays. These findings indicate that MRP4 confers resistance to TPT and TPT is the substrate for MRP4. Further studies are needed to explore the role of MRP4 in resistance to, toxicity and pharmacokinetics of TPT in cancer patients.

Antineoplastic Agents↗
PubMed2006

Characterization of hepatic drug-metabolizing activities of Bama miniature pigs (Sus scrofa domestica): comparison with human enzyme analogs.

We used various substrates and selective inhibitors of human cytochrome P450 (CYP) isozymes as probes to study the metabolism of liver microsomes from Chinese Bama miniature pigs. Nifedipine oxidation (NOD) and testosterone 6beta-hydroxylation (6beta-OHT) activities were similar between human liver microsomes and those from Bama miniature pigs. However, compared with those from humans, liver microsomes from Bama miniature pigs showed decreased phenacetin O-deethylation, coumarin 7-hydroxylation, and chlorzoxazone 6-hydroxylation activities, whereas dextromethorphan O-demethylation activity was increased. Ketoconazole selectively inhibited NOD and 6beta-OHT activities in microsomes from Bama pigs, and 8-methoxypsoralen and tranylcypromine inhibited coumarin 7-hydroxylation in pig microsomes. However, furafylline and quinidine failed to selectively inhibit phenacetin O-deethylation and dextromethorphan O-demethylation in microsomes from Bama pigs, whereas chlormethiazole more efficiently inhibited coumarin 7-hydroxylation activity than chlorzoxazone 6-hydroxylation in pig microsomes. Our results suggest that liver microsomes from Chinese Bama miniature pigs are similar to those from humans in regard to metabolism of nifedipine and testosterone (both are probe substrates for human CYP3A4). In addition, chemical inhibitors used as specific probes for human P450 enzymes did not always show the same selectivity toward corresponding enzyme activities in liver microsomes from Bama pigs. However, ketoconazole (a potent inhibitor of human CYP3A4) could be used as a selective inhibitor probe for the NOD and 6beta-OHT activities in liver microsomes from Chinese Bama miniature pigs.

Adult↗
PubMed2005

[Fluid distribution abnormalities and influence of hemodialysis on fluid distribution in patients on maintenance hemodialysis].

OBJECTIVE: To study the fluid distribution abnormalities in patients on hemodialysis and fluid shift between intracellular and extracellular compartment during hemodialysis (HD). METHODS: Eighty stable end stage renal disease patients on maintenance hemodialysis were selected. Conventional low flux dialyses at dialysate sodium concentration of 138 mmoL/L were performed for all of the patients. Fresenius polysulphons or Gambro hemophon dialyzers were used. All of the patients showed no clinical signs of over ultrafiltration during HD sessions and dry body weights were considered adequate. Intracellular water (ICW), extracellular water (ECW) and total body water (TBW) were measured and standardized by body weight (nICW, nECW, nTBW) before and after HD sessions. Sixty-seven cases of sex, age and body weight matched normal individuals were used as controls. Bio-impedance spectrum (BIS) analysis (Xitron, Technologies, San Diego, CA, USA) was used in body fluid measurement. Pre and post HD nICW, nECW, and nTBW were compared with these of the controls. RESULTS: There were no differences in age, post-dialysis body weight and body mass index between patients on hemodialysis and the controls. Patients on hemodialysis had less nICW [male (0.28+/-0.05) vs (0.33+/-0.04), P<0.01; female (0.22+/-0.03) vs (0.27+/- 0.04), P<0.001], more nECW [male (0.28+/-0.02) vs (0.25+/-0.02), P<0.001; female (0.25+/-0.03) vs (0.23+/-0.01), P<0.05], and less nTBW [male (0.56+/-0.04) vs (0.58+/-0.05), P<0.05; female (0.47+/-0.05) vs (0.49+/-0.03), P<0.05] compared with the controls. The average ultra-filtration volume was (2.2+/-0.9)L. After dialysis, there was an increase in nICW [male (0.28+/-0.05) vs (0.30+/-0.05), P<0.001; female (0.22+/-0.03) vs (0.25+/-0.03), P<0.001), an decrease in nECW [male (0.28+/-0.02) vs (0.26+/-0.03), P<0.001; female (0.24+/-0.03) vs (0.21+/-0.03), P<0.001],and decrease of ECW/ICW ratio [male (1.06+/-0.30) vs (0.89+/-0.25) P<0.001; female (1.10+/-0.17) vs (0.88+/-0.17) P<0.001] which reached the levels of the normal individuals (0.79+/- 0.10 for male, 0.86+/-0.10 for female]. CONCLUSION: Our results show that (1) Before HD sessions, patients on HD had less nICW and more nECW; (2) During conventional low flux HD sessions at dialysate sodium concentration of 138 mmoL/L, fluid shifted from extracellular space to intracellular space.(3) nECW and ECW/ICW ratio from normal population are reasonable for evaluation of dry weight in patients on hemodialysis, but nTBW and nICW are not.

Adult↗
PubMed2005

Phenotyping and genotyping studies of thiopurine S-methyltransferase in Kazaks.

OBJECTIVE: This study was conducted to investigate the thiopurine S-methyltransferase (TPMT) activity distribution and gene mutations in Kazaks, and compared the results with those of other ethnic groups. METHODS: Erythrocyte TPMT activity was measured in Kazaks (n = 327) via a validated high-performance liquid chromatography assay. Polymerase chain reaction-based methods were used to analyze three commonly reporter-inactivating mutations: G238C, G460A, and A719G. RESULTS: Unimodal distribution of TPMT activity was found in Kazaks. Six TPMT*3C heterozygotes and two TPMT*3A heterozygotes were found in 327 Kazaks, with allele frequencies of 0.9 and 0.3%, respectively. The subjects with TPMT*3A and TPMT*3C heterogygotes had substantial TPMT activity over the range of 6.40-11.75 U/ml RBC. CONCLUSION: Unlike in most Caucasians, TPMT*3C is a common mutant allele in Kazaks, whereas TPMT*3A is a rare mutant allele. Further studies are needed to explore the clinical impact of these TPMT mutants to thiopurine therapy in Kazak patients.

Adolescent↗
PubMed2005

Mitochondrial DNA sequence analysis of two mouse hepatocarcinoma cell lines.

AIM: To study genetic difference of mitochondrial DNA (mtDNA) between two hepatocarcinoma cell lines (Hca-F and Hca-P) with diverse metastatic characteristics and the relationship between mtDNA changes in cancer cells and their oncogenic phenotype. METHODS: Mitochondrial DNA D-loop, tRNA(Met+Glu+Ile) and ND3 gene fragments from the hepatocarcinoma cell lines with 1 100, 1 126 and 534 bp in length respectively were analysed by PCR amplification and restriction fragment length polymorphism techniques. The D-loop 3' end sequence of the hepatocarcinoma cell lines was determined by sequencing. RESULTS: No amplification fragment length polymorphism and restriction fragment length polymorphism were observed in tRNA(Met+Glu+Ile), ND3 and D-loop of mitochondrial DNA of the hepatocarcinoma cells. Sequence differences between Hca-F and Hca-P were found in mtDNA D-loop. CONCLUSION: Deletion mutations of mitochondrial DNA restriction fragment may not play a significant role in carcinogenesis. Genetic difference of mtDNA D-loop between Hca-F and Hca-P, which may reflect the environmental and genetic influences during tumor progression, could be linked to their tumorigenic phenotypes.

Animals↗
PubMed2005

The absence of mitochondrial DNA diversity among common laboratory inbred mouse strains.

Mitochondrial DNA (mtDNA), which exhibits a maternal inheritance and a high rate of evolution, has been widely used as a genetic marker when analyzing maternal lineage and inferring phylogenetic relationships among species. In this study, mtDNA variations among four classical (BALB/c, C3H, C57BL/6J and DBA/2) and three Chinese (TA2, 615 and T739) inbred strains of laboratory mice were analyzed by PCR-RFLP (polymerase chain reaction coupled with restriction fragment length polymorphism) and PCR-SSCP (polymerase chain reaction coupled with single-stranded conformational polymorphism) techniques. PCR-RFLP analyses on 46 restriction sites revealed no variations in mtDNA D-loop (displacement loop), tRNA(Met+Glu+Ile) and ND3 (NADH dehydrogenase subunit 3) gene fragments in these strains. Furthermore, PCR-SSCP analyses demonstrated no variations in D-loop 5' and 3' end fragments in them. In view of enormous polymorphisms in mtDNA among mice and dramatic differences in nuclear genomes of these seven strains, our findings were surprising. However, in light of the maternal inheritance of mtDNA, the results indicate that the three Chinese strains, including TA2, T739 and 615, and the four classical strains, share a common maternal lineage.

Animals↗
PubMed2005

[Establishment of transgenic mouse line skin-specifically expressing hCTLA4-Ig].

hCTLA4-Ig,which is capable of inhibiting T cell activation and rendering T cell to be anergy by blocking co-stimulatory signal pathway, is recognized as a potential therapeutic molecule to extend the survival of skin graft in burn medicine. To investigate whether the survival of skin graft can be further extended by skin-specific expression of hCTLA4-Ig, a skin-specific expression vector was constructed by pacing the encoding sequence of hCTLA4-Ig under the drive of K14 promoter, and a transgenic mouse line was established with the vector. RT-PCR and Northern blot assay indicated that hCTLA4-Ig was skin-specifically expressed in transgenic mice at a rather high level. Compared with the expression of GAPDH, the expression of hCTLA4-Ig remained constant through generations and over lifetime. The results of this paper indicated that a transgenic mouse line skin-specifically and constitutively expressing hCTLA4-Ig had been established.

Abatacept↗
PubMed2005

[Study on dechlorination of p-chlorophenol by Ni/Fe bimetallic particles].

Dechlorination property of p-chlorophenol (p-CP) by Ni/Fe bimetallic particles was studied in this work. The experimental results show that adsorbed hydrogen atom is the main reductive agent for dechlorination of p-CP and chemical reaction at the surface of catalyst is the rate-determing step in this process. The catalyst with mass ratio of 2.96% Ni had the largest specific surface area and also had the highest dechlorination efficiencies (64% in 90 min) under the same conditions. The apparent kinetics of p-CP dechlorination by Ni/Fe was the first order reaction and apparent rate constant (kappa) was proportional to the specific surface of catalyst. The apparent rate constant per specific surface area (kappa') was also calculated (7.61 x 10(-4) min(-1) m(-2)). Temperature was also an important parameter in this system. The dechlorination efficiency was proportional to temperature when it is below 43 degrees C, when temperature exceeded 43 degrees C, increasing temperature had inverse effect on dechlorination efficiency.

Chlorophenols↗
PubMed2005

[Isolation and identification of a photosynthetic bacteria producing coenzyme Q10].

13 isolates producing Coenzyme Q10 (CoQ10) of purple non sulfur photosynthetic bacteria were enriched out of pond sludge, one isolate named 2c was selected based on its high CoQ10 content and identified systematically. The gram-negative and short-rod shaped strain 2c is 0.6microm - 0.9microm x 1.2microm - 2.0 microm, has one long flagellum on one end of the cell and contains lamellar intracytoplasmic membrane(ICM) system parallel to cytoplasmic membrane. Cultures produce red pigments in the light. Live cells under phototrophic conditions contain bacteriochlorophyll a and carotenoids. 2c grows anaerobically in the light and aerobically in the dark. Optimal growth occurs at 30degreesC - 35degreesC and at pH7.0 -pH8.0. Various organic compounds are used as photosynthetic electron donors and carbon sources. Peptone and (NH4 )2SO4 are its better nitride source,yeast extracts stimulates its growth. A phylogenetic analysis based on 16S rDNA gene sequences reveales that strain 2c gathers a cluster with 3 strains of Rhodopseudomonas palustris whose accession number in GenBank are AY751758, DQ001155, DQ001158, respectively. 2c subcultures 15 generations stably at least. The results presented here demonstrated strain 2c is Rhodopseudomonas palustris.

Base Sequence↗
PubMed2004

Gene mutation of thiopurine S-methyltransferase in Uygur Chinese.

OBJECTIVE: This study was to investigate the gene mutation of thiopurine S-methyltransferase (TPMT) in Uygur Chinese. METHODS: Polymerase chain reaction-based methods were used to analyze three commonly reported inactivating mutations-G238C, G460A and A719G. RESULTS: One TPMT*3A heterozygote and five TPMT*3C heterozygotes were found in 160 Uygur Chinese subjects, and allele frequencies of TPMT*3A and TPMT*3C were 0.3% and 1.6%, respectively. CONCLUSION: TPMT*3C is a common mutant allele in Uygur Chinese, while TPMT*3A is a rare mutant allele in Uygur Chinese.

Adolescent↗