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Biomedical subjects

X W Li

Publications and source records attributed to X W Li.

At least 19 recordsLinked to original sources
PubMed2006

Seasonal and photoperiodic regulation of secretion of hormones associated with reproduction in Magang goose ganders.

This study examined the reproductive endocrine profile under natural and artificial photoperiods in Magang goose ganders. Group 1 ganders (n=8) served as non-treated controls and were exposed to natural photoperiod throughout the experiment from 13th January to 17th December 2004. Group 2 ganders (n=8) were exposed to 18 h long daily photoperiod for 60 days from 13 January till 15 March 2004 and again to 16 h photoperiod for 75 days till 10th October 2004, and the 11h short photoperiod in the remainder periods of the experiment. In control ganders, plasma LH concentrations were high in normal breeding seasons (August-March) and decreased to low levels in non-breeding season from April to July. Testosterone concentrations changed similarly to that of LH throughout the seasons. Seasonal pattern of PRL concentrations was opposite to those of LH and testosterone, with low values in breeding season and high values in non-breeding season. In artificial photoperiod treated ganders, increasing photoperiod increased PRL and decreased LH and testosterone concentrations, while decreasing photoperiod reversed these changes. There were no seasonal or photoperiod caused changes in plasma T3 concentrations in both control ganders and artificial photoperiod treated ganders. These results demonstrated that in Magang goose ganders that long photoperiod stimulates PRL secretion and decreases LH secretion, which terminates reproductive season in spring and early summer, and short photoperiod stimulates LH secretion and inhibits PRL secretion rendering ganders enter into reproductive season.

Animals↗
PubMed2006

Bioactive ceramic composites sintered from hydroxyapatite and silica at 1,200 degrees C: preparation, microstructures and in vitro bone-like layer growth.

Bioceramic composites were synthesized by sintering the powders of hydroxyapatite (HAp) mixed directly with additive of 0.5, 1.0, 2.0, 5.0 and 10 wt.%SiO(2), respectively, at 1,200( composite function)C. X-ray diffraction (XRD) analysis indicated that the phase transformation from HAp to tricalcium phosphate (TCP) comprising alpha-TCP and Si-TCP occurred and became more prominent with the addition of SiO(2) and the increase in SiO(2) content. The observations of their surface microstructures showed that the addition of SiO(2) suppressed the grain growth and promoted the formation of crystalline-glassy composites denoted HAp + TCP/Bioglass. As the SiO(2) content is as high as 5 wt.%, the composite made a feature of crystalline clusters with different sizes consisting of HAp and TCP grains surrounded by the matrix of glassy phase. Furthermore, the dependence of in vitro bioactivity of these composites on the SiO(2) content was biomimetically assessed by determining the changes in surface morphology, i.e., bone-like apatite layer growth, after soaking in an acellular stimulated body fluid (SBF) for 3 days at 36.5( composite function)C. It was found that the HAp-SiO(2) composites showed a much faster bone-like layer growth than pure HAp, and the propensity of composites to exhibit a better bioactivity was getting more notable with increasing SiO(2) content, except for the case of the highest content of 10 wt.%. It was believed that the formation of the bone-like layer on the surfaces of these bio-composites is closely related to the increasingly provided silanol groups and transformed TCP phase in materials associated with the content of SiO(2) added.

Biocompatible Materials↗
PubMed2006

Further evidence for the association between G72/G30 genes and schizophrenia in two ethnically distinct populations.

Recently, the nested genes G72 and G30 on chromosome 13q32-q33 have been implicated in the etiology of schizophrenia. We genotyped six single-nucleotide polymorphisms (SNPs: rs3916965, rs3916967, rs2391191, rs778294, rs779293 and rs3918342), which span approximately 82.5 kb in the region encompassing the G72/G30 genes in 1176 Han Chinese subjects (588 cases and 588 controls) and 365 Scottish subjects (183 cases and 182 controls). Significant association between an allele of marker rs778293 and schizophrenia was found in our Chinese samples (P = 0.0013), and was replicated in the Scottish samples (P = 0.022). LD analysis revealed that four SNPs between rs3916965 and rs778294 were in LD, called block I, and the two distal SNPs (rs778293 and rs3918342) constituted a block II in both the Chinese and Scottish samples. We selected one SNP from each block (rs778294 from block I and rs778293 from block II), and then analyzed the haplotypes. A significant difference was observed for the common haplotype GC in the Chinese sample (P = 0.0145), and was replicated in the Scottish sample (P = 0.003). On meta-analysis, we separately analyzed the studies in Asian and European populations because of significant heterogeneity in the homogeneity test. We found a statistically significant association between rs778293 and schizophrenia in Asian populations, but no difference was found between cases and controls in the European populations. Overall, our data give further support to the existing evidence that G72/G30 genes are involved in conferring susceptibility to schizophrenia.

Adult↗
PubMed2005

Interleukin-10 -1082 promoter polymorphism is associated with schizophrenia in a Han Chinese sib-pair study.

The interleukin-10 (IL-10) gene has been identified as a susceptibility gene for schizophrenia in Caucasians. A previous case-control study conducted by our group revealed a weak association between polymorphism, -592C/A, of the IL-10 gene promoter and schizophrenia. Our present study was aimed at confirming the association of the IL-10 promoter with schizophrenia using 197 Han Chinese sib-pair families. A family-based association test (FBAT) and haplotype analysis was undertaken using the FBAT v1.5.5. The global TDT was significant for a different polymorphism, -1082G/A (chi2=13.16, P=0.000285) and that the allele -1082G was preferentially transmitted to schizophrenia-affected children. Furthermore, haplotype TDT analysis showed that haplotype "GCC" was significantly associated with the disease (chi2=8.1, P=0.00443). Our results also indicate that the IL-10 gene may play a significant role in the etiology of schizophrenia among Han Chinese.

Adult↗
PubMed2005

Possible association of the MAG locus with schizophrenia in a Chinese Han cohort of family trios.

Neurotransmitter-based hypotheses have so far led to only moderate success in predicting new pathogenetic findings in etiology of schizophrenia. On the other hand, the more recent oligodendroglia hypotheses of this disorder have been supported by an increasing body of evidence. For example, the expression level of the myelin associated glycoprotein (MAG) gene has been shown to be significantly lower in schizophrenia patient groups compared to control groups. Such an effect might be a result of genetic variations of the MAG gene. In order to test this hypothesis, we genotyped four markers within the MAG locus in 413 trios sample of the Han Chinese using allele-specific PCR. None of the four markers revealed noticeable allelic significance. However, the four-marker and two-marker haplotypes covering components rs720309 and rs720308 were observed to be significantly associated with schizophrenia (P < 0.0001) in this study. In addition, we identified one common risk haplotype TA (rs720309-rs720308, present in 78.5% of the general population) that showed increased evidence of overtransmission from parents to affected offspring (P = 0.0001). The results demonstrated MAG might play a role in genetic susceptibility to schizophrenia. Furthermore, our finding of a possible association between the MAG locus and schizophrenia is in agreement with the hypotheses of oligodendrltic and myelination dysfunction.

Adult↗
PubMed2001

[Somatic embryogenesis and plant regeneration in vitro from young shoots of Aralia elate (Miq.) Seem].

Explants excised from the young shoots of Aralia elata (Miq.) Seem. were cultured on MS media. Calli were induced from the explants on MS medium supplemented with 0.5 mg/L 2, 4-D, 0.5 mg/L BA and 0.5 mg/L NAA. Then these calli were transferred onto the MS medium containing 2.0 mg/L 2,4-D + 0.5 mg/L BA + 0.5 mg/L NAA and 0.2% activated charcoal. Under these conditions the somatic embryoids were observed and regenerated plants were obtained from somatic embryogenesis. Then, a experimental system with stability and high regenerating efficiency has been set up for the propagation of the young plants, the cell breeding technology and the control of somatic embryogenesis of Aralia elata (Miq.).

Aralia↗
PubMed2001

[Study on reference laboratory diagnostic index of liver-fire ascending syndrome].

OBJECTIVE: To explore the binding point of Syndrome Differentiation of TCM and disease differentiation by western medicine. METHODS: Selected laboratory diagnostic indexes were tested in 59 cases of Liver-Fire Ascending Syndrome (LFAS). Referring to clinical typing and staging, the data obtained were analysed by same syndrome with different diseases and same disease with different syndrome as well as the values determined in related syndrome-types were compared. RESULTS: The levels of prostaglandin F2 alpha (PGF2 alpha) and arginine vasopressin (AVP) in patients of LFAS were higher than those in patients with Liver-Kidney Yin-Deficiency Syndrome and Liver-Yang Hyperactivity Syndrome. As for linking between Syndrome-type and stage of disease, most cases (70%) of herpes simplex viral keratitis of LFAS were deep matrix layer type; and 100% hypertension patients with LFAS belonged to stage II. CONCLUSION: PGF2 alpha and AVP could be used as the reference laboratory diagnostic indexes of LFAS.

Adult↗
PubMed2001

[Effects of lovastatin combined with cyclosporine A on cultured human peripheral blood mononuclear cells proliferation, cytokines expression and cytotoxicity].

OBJECTIVE: To investigate the effects of lovastatin combined with cyclosporine A (CsA) on cultured human peripheral blood mononuclear cells (PBMC) proliferation, cytokines expression and cytotoxicity in vitro. METHODS: The PBMC was isolated by using Ficoll-Hypague density gradient centrifugation method and its viability was evaluated with LDH-release assay. The effects of lovastatin combined with CsA on cultured PBMC proliferation and cytotoxicity were observed in 3H-TdR incorporation assay. The levels of supernatant IFN-gamma and IL-2 were quantitated respectively with RIA and ELISA-SPOT assay. The IL-2 and IFN-gamma mRNA expressions were determined by RT-PCR. RESULTS: Both lovastatin and CsA inhibited PBMC proliferation, expression of IL-2 and IFN-gamma, and NK cell cytotoxicity in a dose-dependent manner. Combination of the two drugs produced synergism. CONCLUSION: Statins combined with cyclosporine A have a synergic effect and can delay the incidence and development of allograft rejection and prolong the graft life-span in animal models and clinical trials.

Cell Division↗
PubMed2001

[Tuberculosis in patients with chronic renal failure undergoing hemodialysis].

OBJECTIVE: To improve the level of early diagnosis and outcome of tuberculosis (TB) in patients with chronic renal failure on regular hemodialysis (HD). METHODS: Thirteen cases among 306 patients undergoing HD from January 1995 to May 2000 were identified, and the clinical presentations, diagnostic procedures and management were analyzed. RESULTS: The incidence of TB in HD patients was 4.2%. The extrapulmonary TB is common, accounting for 76.9%. The main site of TB was pleural in 4 (30.8%) patients. Most of patients were sensitive to anti-TB agents with the total effective rate of 84.6%. CONCLUSIONS: The TB should be diagnosed carefully and treated promptly if suspected in patients with CRF during the period of HD.

Adult↗
PubMed2000

[A further research on physiopathological basis of "Liver Yang Forming Wind Syndrome"].

The multiple experimental parameters of different aspects in this study were determined in the patients with "Liver Yang Forming Wind Syndrome (LYFWS)", "Qi Deficiency Blood Stagnation Syndrome (QDBSS)" and "Yin Deficiency Forming Wind Syndrome (YDFWS)". The results showed that cerebral hemorrhage was similar to cerebral infarction in almost all parameters and the two diseases were with LYFWS. It was found that there were several characteristics in LYFWS, i.e. 1. Hyperfunction of sympathetic adrenal medullary system. 2. Hypotriiodothyroidoglobulin syndrome. 3. The marked changes of the active substance regulating vessel smooth muscle function. 4. The increased inflammatory medicators. The pathophysiological parameters in patients with QDBSS were the same as those with YDFWS, but the changes of QDBSS and YDFWS weRe milder than those of LYFWS.

6-Ketoprostaglandin F1 alpha↗
PubMed2000

[Effect of anticancer polypeptide from Buthus Martensii venom on immune function in the H22-bearing mice].

OBJECTIVE: To observe the effect of anticancer polypeptide from Buthus Martensii Venom (APBMV) on Immune function in the H22-bearing mice. METHODS: The MTT colorimetric method, homolysin assay, lymphocyte transformation test, delayed hypersensitivity assay and WBC-count of peripheral blood were used in this study. RESULTS: APBMV could obviously augment NK activity, promote proliferation of lymphocytes induced by Con A, potentiate the response of DTH induced by DNCB, antagonize the decrease of WBC in peripheral blood induced by 5-Fu in the H22-bearing mice. CONCLUSION: APBMV can obviously increase immune function in the H22-bearing mice and antagonize hypoimmunity immunodeficiency or immunodeficiency induced by chemotherapy or the tumor.

Animals↗
PubMed2000

[The development of a brain surgery path planning system].

Based on the patient's CT/MRI Section images, the brain surgery path Planning system makes surgeon freely draw out the interesting regions through the use of feasible interactive drawing contour function. And by fast judgement, the system is able to give out the risky value of the path. Finally, the system would directly show the surgery path in 3-D display.

Brain↗
PubMed1999

Wild-type p53 protein potentiates phototoxicity of 2-BA-2-DMHA in HT29 cells expressing endogenous mutant p53.

To better understand the effects of p53 on the process of photodynamic therapy (PDT)-induced cell death, we introduced a wild-type p53 gene into the HT29 colorectal carcinoma cell line, which bears an endogenous mutant p53, using a lipofectin system. The influence of p53 status on the sensitivity induced by 2-butylamino-2-demethoxy-hypocrellin A (2-BA-2-DMHA) photosensitization was then examined. The results indicate that infection with wild-type p53 induces a growth arrest but does not induce cell death, and sensitizes the cells to PDT. At a concentration of 5 microM 2-BA-2-DMHA with a red light of 18 J/cm2 (lambda = 600-700 nm), the survival is reduced from 58.72% in HT29 cells to 13.49% in wild-type p53-infected HT29 cells. Apoptosis following PDT appears earlier in HT29 cells infected with wild-type p53 than in parent HT29 cells and empty vector-infected HT29 cells. These findings suggest that although wild-type p53 is, by itself, insufficient to induce apoptosis in cells with p53 mutation, it enhances the photosensitivity of 2-BA-2-DMHA by strongly potentiating the induction of apoptosis.

Apoptosis↗
PubMed1998

Enhanced sensitivity of the nucleus accumbens proenkephalin system to alcohol in rats selectively bred for alcohol preference.

Evidence suggests that alcohol-induced activation of the endogenous opioid system is part of a neurobiological mechanism that may be functionally involved in alcohol reinforcement and high alcohol drinking behavior. We postulate that a genetic predisposition toward alcohol drinking is accompanied by increased responsiveness of the opioid system to alcohol. To test this hypothesis, the present study compared the effect of an acute alcohol challenge on enkephalin gene expression in discrete brain regions which are high in preproenkephalin (PPENK) mRNA content and/or are important in mediating alcohol reward in rats selectively bred for alcohol preference (P) or nonpreference (NP). PPENK mRNA content was measured by in situ hybridization performed with a 36 base oligonucleotide probe for PPENK mRNA and was quantified using a computerized image-analysis system. Blood alcohol concentration (BAC) and rate of alcohol elimination following alcohol infusion were similar in P and NP rats. P and NP rats did not differ in basal content of PPENK mRNA in any of the brain areas examined prior to onset of infusion. An intragastric (I.G.) infusion of alcohol (2.5 g/kg b.wt) produced a significant increase in PPENK mRNA in the nucleus accumbens (both shell and core) of P but not NP rats at 1 h after the onset of infusion which coincided with the time at which peak BAC was attained. In contrast, at 8 h after the onset of the alcohol infusion, when BAC was falling toward baseline, PPENK mRNA was decreased in the nucleus accumbens of both P and NP rats and in the anterior striatum and amygdala of NP rats. The results suggest that enhanced responsiveness of the enkephalinergic system to alcohol is associated with, and may be functionally involved in, mediating high alcohol drinking behavior.

Alcohol Drinking↗
PubMed1998

Effect of mu opioid receptor blockade on alcohol intake in rats bred for high alcohol drinking.

Beta-funaltrexamine (beta-FNA), a selective mu opioid receptor antagonist, when administered in doses of 10.0, 15.0, and 20.0 mg/kg b.wt., decreased alcohol but not water intake in a dose-dependent manner in rats selectively bred for high alcohol intake (HAD line). Beta-FNA also suppressed the intake of a saccharin solution containing alcohol without altering the intake of a similar solution without alcohol. The results suggest that beta-FNA may prove useful as a pharmacotherapeutic agent for the treatment of alcohol dependence. In a second study, pituitary beta-endorphin gene expression (proopiomelanocortin or POMC messenger ribonucleic acid-mRNA) was compared in another pair of rat lines selectively bred for high or low alcohol intake (alcohol-preferring or P and alcohol-nonpreferring or NP lines). A repeated alcohol challenge (1.0 g/kg b.wt./day, IP for 4 days) produced a greater increase in POMC mRNA in the anterior and neurointermediate lobes of the pituitary of P rats compared with NP rats. The results suggest that a genetic predisposition toward high alcohol drinking may be associated with increased responsiveness of the opioid system to alcohol.

Alcohol Drinking↗
PubMed1997

Immunoaffinity column cleanup procedure for analysis of ivermectin in swine liver.

A simple and sensitive method for the analysis of ivermectin (22,23-dihydroavermectin B1) in swine liver based on immunoaffinity column cleanup is described. The immunosorbent was prepared by coupling polyclonal anti-ivermectin antibodies to carbonyl diimidazole-activated Sepharose CL-4B. After extraction with methanol, ivermectin was cleaned up on an immunoaffinity column, and determined by reversed-phase liquid chromatography with UV absorbance detection at 245 nm. Recoveries of ivermectin from fortified samples of 5-10 micrograms kg-1 levels ranged 85-102%, with coefficients of variation of 6-12%. The limit of detection was 2 micrograms kg-1 in a 5-g samples.

Animals↗