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Biomedical subjects

Li Zhang

Publications and source records attributed to Li Zhang.

At least 397 records · Page 22Linked to original sources
PubMed2005

[Changes of masticatory muscles after occlusal recovery in rats with unilateral chew].

PURPOSE: To study the effect of occlusal recovery on masticatory muscles in rats with unilateral chew. METHODS: 40 white rats were divided into two experimental groups and two control groups. The right upper and lower posterior teeth of all the rats were ground to the gingival level without occlusal contact. The rats of the first experimental and control group were killed 10 weeks late,those of the second groups were killed 16 weeks late. The pathological changes of masticatory muscles were studied. SPSS 10.0 software package was used for statistical analysis. RESULTS: There was significant correlation between the first experimental group and control group in the damage of masticatory muscles (Chi(2)=40, P<0.01). However,there was no significant correlation between the second experimental group and control group in the damage of masticatory muscles (Chi(2)=3.66, P>0.05). CONCLUSION: Early occlusal recovery can rehabilitate the damage of masticatory muscles in rats with unilateral chew.

Animals↗
PubMed2005

[Intergration and epression of porcine endogenous retrovinus in the immortal cell line of Banna Minipig Inberd Line-Mesenhymal Stem Cells].

OBJECTIVE: To detect the integration and expression of porcine endogenous retrovirus (PERV) in the immortal cell line of Banna Minipig Inbred Line-Mesenchymal Stem Cells (BMI-MSCs). METHODS: DNA and total RNA of the immortal cell line of BMI-MSCs were extracted and PCR, RT-PCR were performed to detect PERV-gag, pol and env gene, and the type of PERV was also detected. RESULTS: PERV-gag, pol and env gene were all detected in the primary culture and immortal cell line (passage 150 and passage 180) of BMI-MSCs, and the type of PERV was PERV-A, B. Functional expression of PERV-gag and pol mRNA was also detected. CONCLUSION: In this laboratory, PERV was not lost during the proceeding of pig inbred and since has been in long-term culture of pig cells in vitro. PERV has integrated into the genome of its natural host, and virus mRNA can effectively express. So it is very essential to evaluate the possibility of xenozoonoses in pig-to-human xenotransplantation.

Animals↗
PubMed2005

[Influence of obstructive sleep apnea-hypopnea syndrome in children on hearing problem].

OBJECTIVE: To analyze the effects of obstructive sleep apnea hypopnea syndrome on hearing among children. METHODS: One hundred and forty three apnea children proved with overnight polysomnography received pure tone audiometry, acoustic impedance test, and lateral nasopharyngeal airway X-ray. Hearing threshold level and blood oxygen's saturation, apnea hypopnea index were analyzed. RESULTS: Among the 127 cases,63 cases had type C or B tympanograms, and 33 of them had lifted hearing threshold level. The remaining 64 cases had normal hearing and tympanograms. It was found correlation between the A/N ratio and blood oxygen's saturation, and no correlation between the A/N ratio and average of hearing threshold level. There was no correlation between AHI and average of hearing threshold level of each group. Hearing level can be improved after adenoidectomy or adenotonsillectomy. CONCLUSIONS: The upper airway obstruction due to adenotonsillar enlargement is common in children. It also affects the middle-ear impedance. Although short -term and mild degree of hypoxemia has few influence on hearing threshold level, it may affect cochlear function.

Acoustic Impedance Tests↗
PubMed2005

[Clinical analysis of liver damage of 116 malignant lymphoma patients with chronic HBV infection after cytotoxic chemotherapy].

BACKGROUND & OBJECTIVE: Chronic hepatitis B virus (HBV) infection increases the prevalence of liver damage and related death of malignant tumor patients. This study was to investigate the prevalence of liver damage and clinical results in lymphoma patients with chronic HBV infection after standard chemotherapy, and assess high risk factors associated with liver damage for better guidance in clinic. METHODS: Records of 116 lymphoma patients with chronic HBV infection, treated with standard chemotherapy from Jan. 1985 to Jan. 2002 in Cancer Center of Sun Yat-sen University, were reviewed to analyze the prevalence of liver damage, clinical results, and related high risk factors. RESULTS: Of the 116 patients, 60 (51.7%) suffered liver damage. According to WHO criteria of liver toxicity, 4 (3.4%) were in grade I, 14 (12.1%) in grade II, 15 (12.9%) in grade III, and 27 (23.3%) in grade IV. After treatment for liver damage, 11 (9.5%) patients completed chemotherapy without delay, 27(23.3%) completed chemotherapy with delay of more than 8 days, 16 (13.8%) terminated chemotherapy, 6 (5.2%) died. Logistic multivariate analysis showed that steroid was a high risk factor of liver damage after chemotherapy. CONCLUSIONS: The prevalence of liver damage is high in lymphoma patients with chronic HBV infection after standard chemotherapy, which led to treatment delay or discontinue, even death. Steroid is a high risk of liver damage.

Adolescent↗
PubMed2005

[The pharmacokinetics of rhein in 12 healthy volunteers after oral administration of rhubarb extract].

OBJECTIVE: To study the pharmacokinetics of rhein in 12 healthy volunteers after oral administration of rhubarb extract. METHOD: The blood sample were obtained at 0,0.083,0.5,1,1.5,2,3,4,5,7,10 h after a single dose oral administration of rhubarb (50 mg x kg(-1)). The plasma rhein concentration was determined by HPLC. The pharmacokinetics of rhein were analysed by 3P97 program. RESULT: The absorption of rhein was very fastafter oral administration of rhubarb extract in the healthy volunteers. The main pharmacokinetic parameters of rhein were C(max) (3.20 +/- 1.08) microg x mL(-1); t(max) (1.03 +/- 0.41) h; t(1/2alpha) (0.21 +/- 0.02) h; t(1/2beta) (2.68 +/- 1.09) h; MRT(5.31 +/- 1.78) h; AUC(0-infinity) (1 573.08 +/- 366.48) microg x mL(-1) min(-1), respectively. CONCLUSION: Rhein could be absorbed rapidly and its pharmacokinetics was consistent with two-compartment model.

Administration, Oral↗
PubMed2005

[Study on an epidemic caused by the vaccine-derived poliovirus circulation in Guizhou province, 2004].

OBJECTIVE: To study the circulating vaccine-derived poliovirus (cVDPVs) that occurred in Zhenfeng county, Guizhou province in 2004 and to discover wild-poliovirus, vaccine-derived poliovirus (VDPVs) and other vaccine-associated poliovirus which could cause clinical poliomyelitis. METHODS: Field epidemiological studies at the epidemic area and collecting acute flaccid paralysis (AFP) case and contact stool specimen for virus identification and nucleotide sequencing. Analysis on data related to annual reports on stool specimens surveillance which involved AFP case and contacts in the resent years in Zhenfeng county. RESULTS: Type-I VDPVs had been isolated from 2 AFP cases and 3 contact stool specimen in Wanlan village of Zhenfeng. After the first cVDPVs case was identified, there were 3 cases identified of having other vaccine-associated poliovirus of type-I or type-II in the 5 case of AFP that met the criteria of clinical poliomyelitis. The result of virological surveillance on polio showed that the EV isolation rate (55.1%) of Zhenfeng county was higher than the rate from the whole province of the same year (23.2%). The poliovirus (PV) isolation rate (36.8%) was obviously higher in 2004 than in the previous years. In the 16 PVs strains, the type-I accounted for 43.8% which was significantly higher than the average level (18.3%) from the whole province. CONCLUSIONS: Data indicated that the type-I VDPVs had been circulating (cVDPVs) in Zhenfeng county in Guizhou province. Clinical poliomyelitis was caused by non-VDPVs. The increased PV infection and the decreasing rate of vaccination in the general population were responsible for the epidemic of type-I cVDPVs at this time. Monitoring and evaluation on the rate of routine immunization program and prediction of the trend of epidemic should be strenthened.

Adolescent↗
PubMed2005

[Effects of extract from Cornus officinalis on nitric oxide and NF-kappaB in cortex of cerebral infarction rat model].

OBJECTIVE: To observe the change of nitric oxide (NO) and expression of nuclear factor-kappa B (NF-kappaB) in the cortex of cerebral infarction rat induced by photochemical reaction, and study the effect of extract from Cornus officinalis (whose main ingredient is iridoid glycoside) in the course of disease. METHOD: After rats were fed with experimental drugs for 7 days, the model of cerebral infarction was induced. Spectrophotography and immunohistochemistry were used to detect the change of the content of NO, NOS and the expression of NF-kappaB in the cortex. RESULT: Compared with control group, distinct infarction was visible in the model group, and the content of NO, the activity of NOS and the positive cell number of NF-kappaB were increased obviously. Compared with model group, the extract of C. officeinalis decreased the area of infarction, the content of NO, the activity of NOS and the positive cell number of NF-kappaB. CONCLUSION: The iridoid glycoside of C. officinalis may have therapeutical effect on cerebral infarction through regulating the content of NO and NF-kappaB.

Animals↗
PubMed2005

[Spectroscopic studies of interaction of brilliant cresyl blue and DNA].

The interaction of dye brilliant cresyl blue (BCB), which features a phenoxonium group, with hydroxypropyl-beta-cyclodextrinl and DNA in aqueous solution was studied by spectroscopic methods. The experimental results indicate that BCB can be included into the hydrophobic cavity of HP-beta-CD to form an inclusion, a complex with a stability constant of 1.98 x 10(3) L x mol(-1). At low DNA concentrations, BCB can be bound to DNA to form a 1:1 association complex with the binding constant of 4.3 x 10(4) mol x L(-1), and the major binding model of BCB to DNA is "electrostatic binding". However, the major binding model changes to "intercalative binding" at high DNA concentrations. In addition, the interactions of BCB-(HP-beta-CD) inclusion complex and DNA have been investigated. The results suggest that BCB displayed a high affinity for DNA and the inclusion complex decomposed when it was bound to DNA.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed2005

[Chemical forms of heavy metals in the soils and plants of copper tailings yard].

The study on the chemical forms of heavy metals in the soils and plants at the copper tailings yard in Tongling City indicated that the soils were extremely poor, with organic mater content being 2.6-5.8 g x kg(-1), only 1/15 of the control, while their Cu, Cd, Pb and Zn contents were higher than the control, with Cu 809.30-1395.54 mg x kg(-1) and Cd 3.25-6.35 mg x kg(-1), as 30-60 times as those of the control. The heavy metals contents in Zoysia japonica and Trifolium pratense had a significantly positive correlation with the contents of their exchangeable and organic forms in soils, a significantly or very significantly negative correlation with the forms of Fe-Mn oxides and carbonate, and no correlation with residual form. The main forms of Cu, Zn and Pb in Z. japonica and T. pratense were HAC-and HCl-extractable, and residual. The NaCl-extractable Zn content in the roots, stems and leaves of Z. japonica and T. pratense occupied a higher proportion, while NaCl-extractable Cd was the main form of Cd in both of the plants, not only in their roots but also in their leaves.

China↗
PubMed2005

[Long-term outcomes of 392 non-Hodgkin's lymphoma patients treated with pirarubicin based regimens].

OBJECTIVE: To analyse the effectiveness and toxicity of combined chemotherapy regimen containing pirarubicin (THP) in the treatment of non-Hodgkin's lymphoma (NHL). METHODS: Three hundred and ninety two patients with NHL were treated by THP containing regimen with or without involved field radiotherapy. The clinical characteristics, response, toxicity and long-term survival rates were analysed. RESULTS: The median age of the patients was 47 (5 - 87) years and 26.0% aged more than 60 years. 61.0% of the patients were males and 39.0% females. B-cell and T/NK cell NHL accounted for 68.4% and 23.2% respectively with 56.9% of diffuse large B cell lymphoma and 12.5% of peripheral T cell lymphoma. 92.6% of the patients were ECOG < 1, 63.2% in stage I + II, 84.7% with IPI score 0 - 2 and 25% with B symptoms, 93.9% (368/392) of the patients received CTOP (containing THP) regimen chemotherapy and among them 28.5% (112/392) plus involved field radiotherapy. Altogether 1598 courses were administered on 368 patients. The overall response rate was 88.5% (341/385) with a complete remission (CR) rate of 63.6%, major toxicity was myelosuppression with 12.8%, 1.0% and 1.5% of grade III - IV neutropenia, thrombocytopenia and anemia, respectively. G-CSF support was given for 553 courses (34.6%). Alopecia account for 19.8%. The incidence of mild cardiotoxicity was 5.8%. Treatment-related mortality was 1.6% (6/368). Median follow-up was 24 months. The 1, 3 and 5 year actuarial survival rates were 86.4% , 66.5% and 59.2%, respectively. Median survival time has not been achieved. CONCLUSION: The efficacy of THP based regimen CTOP for the treatment of aggressive NHL is promising. Further clinical trial is warranted.

Adolescent↗
PubMed2005

[Analysis on the changing of age patterns among rubella patients after rubella vaccine immunization for children in Shandong Province, China].

OBJECTIVE: To analyze the changing of age patterns among rubella patients after implementing rubella vaccine immunization to children in Shandong province since 1995. METHODS: Epidemiologic data on rubella through surveillance system for suspected measles from 1999 to 2004 and data on rubella vaccination were used and analyzed. RESULTS: The annual average incidence rate of rubella from 1999 to 2004 had been 0.59 per 100 thousands population while 81.17% of cases were concentrated during the outbreaks. 77.77% of the cases were school children between 7-15 years old and 7.93% of the cases were under 7 years old. The age-median of cases were 10.37, 11.66, 11.41, 12.81, 14.28 and 13.96 years old from 1999 to 2004, respectively. The estimated coverage of rubella vaccine for pre-school children was about 60% but only 20% were for school children. CONCLUSION: The peak age of cases moved from youth towards adolescence which indicated that women with child-bearing age might have been under risk of developing the congenital rubella syndrome (CRS). It is necessary to carry out screening test of rubella antibody and vaccination to women with child-bearing age and the immunization strategy should be established to guide the control of rubella and CRS.

Adolescent↗
PubMed2004

Dual function for a unique site within the beta2I domain of integrin alphaMbeta2.

Integrin activation has been postulated to occur in part via conformational changes in the I domain of the beta subunit (the betaI domain), especially near the F-alpha(7) loop, in response to "inside-out" signaling. However, direct evidence for a role of the F-alpha(7) loop in ligand binding and activity modulation is still lacking. Here, we report our finding that the F-alpha(7) loop (residues 344-358) within the beta(2)I domain has dual functions in ligand binding by alpha(M)beta(2). On the one hand, it supports intercellular adhesion molecule 1 (ICAM-1) binding to alpha(M)beta(2) directly as part of a recognition interface formed by five noncontiguous segments (Pro(192)-Glu(197), Asn(213)-Glu(220), Leu(225)-Leu(230), Ser(324)-Thr(329), and Glu(344)-Asp(348)) on the apex of the beta(2)I domain. On the other hand, it controls the open and closed conformation of the alpha(M)beta(2) receptor, thereby indirectly affecting alpha(M)beta(2) binding to other ligands. Switching the five constituent sequences of the ICAM-1-binding site within the beta(2)I domain to their beta(1) counterparts destroyed ICAM-1 binding but had no effect on the gross conformations of the receptor. Of the five ICAM-1 binding-defective mutants, four had normal or even stronger interaction with Fg and C3bi, as reported in our previous study. Synthetic peptides derived from the identified site inhibited alpha(M)beta(2)-ICAM-1 interaction and supported direct binding to ICAM-1. Most importantly, perturbation of the F-alpha(7) loop caused conformational changes within the beta(2)I domain, which was further propagated to other regions of alpha(M)beta(2). Altogether, our data demonstrate that inside-out signaling could modulate ligand binding directly by changing the ligand-binding pocket per se and/or indirectly by inducing multiple conformational changes within the receptor.

Antibodies, Monoclonal↗
PubMed2004

Evaluation of the first-pass glucuronidation of selected flavones in gut by Caco-2 monolayer model.

PURPOSE: Four flavones, namely Apigenin, Baicalein, Chrysin and Luteolin, were selected for study and comparison of their absorption and metabolism in gut using the in vitro Caco-2 monolayer model. METHODS: Transport of the four flavones in the Caco-2 monolayer model was studied in both Apical-to-Basolateral and Basolateral-to-Apical directions. RESULTS: All of the selected flavones were able to pass through the Caco-2 cell monolayer with no significant efflux. The permeability coefficients of the four compounds were all greater than 10(-6) cm/sec and those of Apigenin and Baicalein were even greater than 10(-5) cm/sec. Glucuronides of the tested flavones were all formed in the Caco-2 cell monolayer model and a structure-activity relationship has been proposed for this glucuronidation. In addition, Apical-to-Basolateral transport studies were performed in Caco-2 models pre-treated with Chrysin, an UGT inducer. Quantities of the corresponding glucuronides formed were all significantly higher in Chrysin-treated groups than the controls. CONCLUSIONS: It demonstrated that all selected flavones were substrates of the UGT isoforms that are inducible by Chrysin.

Biological Transport↗
PubMed2004

Kinetics of haloacetic acid reactions with Fe(0).

Detailed kinetic studies of the reactions of haloacetic acids (HAAs) with Fe(0) were performed in longitudinally mixed batch reactors. The reactions of tribromoacetic acid (TBAA), bromodichloroacetic acid, and chlorodibromoacetic acid were mass transfer limited, with corrected mass transfer coefficients of 3.7-3.9 x 10(-4) m/s. The reactions of trichloroacetic acid (TCAA), dichloroacetic acid (DCAA), chloroacetic acid (CAA), and bromoacetic acid (BAA) were reaction limited. Bromochloroacetic acid (BCAA) and dibromoacetic acid (DBAA) were partially reaction limited. For the reaction limited species and partially reaction limited species, intra- and interspecies competition effects were observed. A Langmuir-Hinshelwood-Hougen-Watson kinetic model incorporating a mass transfer term was adopted to account for these effects. The lumped kinetic parameters for the HAAs ranged from 0.04 to 248 microM min(-1) for an iron loading of 0.3 g of Fe/125 mL and followed the trend DBAA > BCAA > TCAA > BAA > DCAA. The adsorption parameters ranged from 0.0007 to 0.0065 microM(-1). The effect of dissolved oxygen (DO) on the reaction of TBAA or BAA with Fe(0) was also investigated. No significant effect of DO on the reaction rate of TBAA, which is a mass transfer limited species, was observed. A lag phase, however, was observed for the reaction of BAA, which is a reaction limited species, until the DO was depleted. Simulations were performed to investigate the potential significance of the reactions of HAAs with Fe(0) in water distribution systems.

Acetates↗
PubMed2004

Investigation of intestinal absorption and disposition of green tea catechins by Caco-2 monolayer model.

The current study was designed to investigate the absorption mechanism and identify the possible disposition pathways of green tea catechins (GTC), including epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), during their absorption across small intestine by Caco-2 monolayer model. The transport of each GTC from both apical to basolateral and basolateral to apical directions was measured in the absence and the presence of MK571, an MRP inhibitor. HPLC and LC/MS were employed to identify the possible metabolites of the four GTC formed during their bidirectional transport processes. The results indicated that the four GTC showed limited transepithelial absorption with relatively small P(app) values. However, significant efflux mediated by MRP was observed during the secretion of GTC, especially the non-gallated catechins. Methylation and sulfation were the main biotransformation pathways of GTC during their secretion transport and the efflux of the related metabolites seem to be mediated by MRP.

Biological Transport↗
PubMed2004

Direct fluorimetric determination of ascorbic acid by the supramolecular system of AA with beta-cyclodextrin derivative.

We established a simple and selective fluorimetric method for the determination of ascorbic acid (AA) with the novel mono-[6-N(4-carboxy-phenyl)]-beta-cyclodextrin (ACD). The method is based on the fluorescence intensity of ACD decreases as the ACD-AA supramolecular complexes form. The fluorescence intensity is measured at excitation and emission wavelengths of 270 and 352 nm, respectively. Under optimum condition, a linear relationship is obtained between the fluorescence intensity and the concentration of AA in the range of 0.05-8.0 microgml(-1). The detection limit is 0.012 microgml(-1). The method has been applied to the direct analysis of AA in real samples with satisfactory results.

Absorption↗
PubMed2004

Expression of the ammonia transporter proteins Rh B glycoprotein and Rh C glycoprotein in the intestinal tract.

Ammonia metabolism is important in multiple aspects of gastrointestinal physiology, but the mechanisms of ammonia transport in the gastrointestinal tract remain incompletely defined. The present study examines expression of the ammonia transporter family members Rh B glycoprotein (RhBG) and Rh C glycoprotein (RhCG) in the mouse gastrointestinal tract. Real-time RT-PCR amplification and immunoblot analysis identified mRNA and protein for both RhBG and RhCG were expressed in stomach, duodenum, jejunum, ileum, and colon. Immunohistochemistry showed organ and cell-specific expression of both RhBG and RhCG. In the stomach, both RhBG and RhCG were expressed in the fundus and forestomach, but not in the antrum. In the forestomach, RhBG was expressed by all nucleated squamous epithelial cells, whereas RhCG was expressed only in the stratum germinativum. In the fundus, RhBG and RhCG immunoreactivity was present in zymogenic cells but not in parietal or mucous cells. Furthermore, zymogenic cell RhBG and RhCG expression was polarized, with apical RhCG and basolateral RhBG immunoreactivity. In the duodenum, jejunum, ileum, and colon, RhBG and RhCG immunoreactivity was present in villous, but not in mucous or crypt cells. Similar to the fundic zymogenic cell, RhBG and RhCG expression in villous epithelial cells was polarized when apical RhCG and basolateral RhBG immunoreactivity was present. Thus the ammonia transporting proteins RhBG and RhCG exhibit cell-specific, axially heterogeneous, and polarized expression in the intestinal tract suggesting they function cooperatively to mediate gastrointestinal tract ammonia transport.

Animals↗