Search PubMed⌕ Search

Biomedical subjects

Z Li

Publications and source records attributed to Z Li.

At least 559 records · Page 31Linked to original sources
PubMed2000

[Autogenous costochondral graft applied in the reconstruction of the temporomandibular joint].

OBJECTIVE: To study the surgical treatment of ankylosis of the temporomandibular joint. METHODS: Autogenous costochondral grafts were applied in the reconstruction of the temporomandibular joint in 27 cases with condyle ankylosis from 1988-1998. The follow up period was 1-10 years. The pre- and post-operative degree of mouth opening and the TMJ function was examined. RESULTS: Postoperative mouth opening was improved up to 2 cm in the 27 cases. All the results were successful without recrudescence of condyle ankylosis. CONCLUSION: The use of autogenous costochondral grafts in TMJ reconstruction is the best method in the treatment of TMJ ankylosis.

Adolescent↗
PubMed2000

[Landscape heterogeneity of urban vegetation in Guangzhou].

Seven indexes were used to study the landscape heterogeneity of vegetation in Guangzhou City. The results show that the patch density was 11.8 patches.km-2 and the line corridor density was 1.87 km.km-2. In old urban area, the vegetation landscape was characterized by small patches, heavy fragmentation, high diversity and random distribution, showing a highly heterogeneous spatial pattern, while in new urban area, the vegetation landscape was characterized by big patches and even distribution. Therefore, when the size of vegetation area was the same, the even distribution of vegetation could improve the landscape heterogeneity and make the ecological function more effective.

China↗
PubMed2000

[Accumulation of ABA and ODAP in Lathyrus sativus under water stress].

The roots of fifteen days old Lathyrus sativus seedlings were treated by PEG, PEG + ABA and ABA, and their leaves were sampled to determine the contents of endogenic ABA, ODAP, MDA and H2O2 and the activity of superoxide dismutase, catalase, peroxidase and glutathione reductase. The results showed that after treated, the contents of ABA and ODAP in leaves increased markedly. The addition of exogenous ABA decreased the increment of MDA and H2O2 contents and retarded the attenuation of CAT activity, which were induced by PEG stress, and enhanced the GR activity. In addition, when materials were treated with exogenous ABA in a long time, the ABA content in leaves was increased markedly, and ODAP was then accumulated. There was no significant effect on metabolism of active oxygen in the early days(0-3 days) of ABA treatment, but the activities of SOD, POD, CAT and GR decreased, and the contents of MDA and H2O2 increased in leaves of Lathyrus sativus with the duration of ABA treatment(7-15 days). The results indicated that ABA could promote the accumulation of ODAP in leaves of Lathyrus sativus.

Abscisic Acid↗
PubMed2000

[Effect of cadmium on soil animal community structure].

A indoor simulating test showed that there existed a close relationship between the community structure of soil animal and the concentration of soil Cd. When the concentration of soil Cd was high (99.48 mg.kg-1), the species, quantity, diversity index, homogeneous index, and abundance of soil animal were low. With the concentration going down, all indexes above increased gradually. When the concentration of soil Cd was 2.27 mg.kg-1, all the indexes were the same as control. The species and individuals of soil animal were negatively related with the natural logarithm of Cd concentration in soil.

Animal Population Groups↗
PubMed2000

[Effect of combined treatment of 60Co gamma-ray and EMS on antioxidase activity and ODAP content in Lathyrus sativus].

Lathyrus sativus seeds were treated with 60Co gamma-ray and EMS(ethyl methane sulfonate), and their emergence rate and SOD, POD and CAT activities were determined. The result indicated that the treatment decreased the emergence rate. The activities of SOD and POD were changed in accordance with the increase of irradiation dose and EMS concentration, while that of CAT had no obvious change. After treatment, the ODAP content in Lathyrus sativus decreased. Amutant was developed, with toxin content of 0.1%, compared to 0.2% in control.

Amino Acids, Diamino↗
PubMed2000

[Nutrient content in litterfall and its translocation in plantation forests in south China].

The amounts of litterfall, nutrient content in it and leaves of five plantation forests in south China were determined. The order of litterfall biomass was in sequence of Acacia mangium (11.1 t.hm-2) > Pinus elliotii (7.3 t.hm-2) > Schima superba (6.5 t.hm-2) > Acacia auriculaiformis (4.8 t.hm-2) > Eucalyptus citriodora (2.6 t.hm-2). A. mangium returned soil much more nutrient to soil through litterfall than other forests did. N, P and K were largely translocated from senescing leaves for all the five forests, and especially for A. mangium. Nutrient translocated varied greatly with seasons. The translocation of other elements was not definite.

Biomass↗
PubMed2000

[Changes of plasma levels of type C natriuretic peptide in patients with pregnancy induced hypertension].

OBJECTIVE: To investigate the changes and clinical significance of plasma type C natriuretic peptide (CNP) concentration in patients with pregnancy induced hypertension (PIH). METHODS: Plasma CNP levels were detected by radioimmunoassay in 89 patients with PIH, 193 normal pregnant women and 46 normal non-pregnant women. Outcomes were statistically analyzed by one-way analysis of variance and Student-Nawman-Kenls (SNK) test. RESULTS: The plasma CNP levels in patients with PIH [(30.51 +/- 33.61) ng/L] were significantly higher than those of normal non-pregnant women and normal pregnancies [(17.15 +/- 3.82) ng/L, (19.43 +/- 5.13) ng/L, respectively; F = 13.61, P < 0.01]. There was significant difference among plasma CNP levels from patients with mild, moderate, and severe PIH (P < 0.0001). CONCLUSIONS: The changes of plasma CNP levels are believed to be the reflection of patients in progression of PIH and can be used as a biochemical marker for judging the progression and guiding the therapy of PIH.

Adult↗
PubMed2000

[Prediction of malignant transformation of hydatidiform mole by mRNA determination of matrix metalloproteinases and tissue inhibitor of metalloproteinases].

OBJECTIVE: To investigate the relationship between the messenger RNA(mRNA) levels of matrix metalloproteinases(MMP-9, MMP-2) and tissue inhibitor of metalloproteinase (TIMP-1, TIMP-2) and malignant transformation of hydatidiform mole. METHODS: Total RNA were isolated from tissues of 22 normal chorionic villi samples and 37 cases of hydatidiform mole. The mRNA expression of MMP-9, MMP-2, TIMP-1, TIMP-2 genes were determined by RT-PCR. RESULTS: The differences of the mRNA expression of MMP-9, MMP-2, TIMP-1, TIMP-2 genes in the tissues of hydatidiform mole and normal preganacy villus were not significant (P > 0.05). The ratio of MMP-9/TIMP-1 in molar tissues with malignant transformation was higher than those in molar tissues without malignant transformation and in normal villus. CONCLUSION: It is a correlative relation beween MMP-9/TIMP-1 and malignancy of hydatidiform mole. The ratio of MMP-9/TIMP-1 might be used as an index for prediction of malignant transformation of hydatidiform mole.

Adult↗
PubMed2000

von Willebrand disease in China.

PURPOSE: To review the molecular pathogenesis in Chinese patients with von Willebrand disease (vWD) and polymorphisms of von Willebrand factor (vWF) in Chinese population. DATA SOURCES: Both Chinese and English language literature search using MEDLINE (1985-1998), and original articles published in main Chinese and international journals. STUDY SELECTION AND DATA EXTRACTION: After reviewing of the literature, 19 articles of them were selected that specifically addressed the stated purpose. RESULTS: The molecular pathogenesis of vWD was variant. Six cases of point mutation have been found in Chinese patients with vWD. The system of site-directed mutagenesis and expression of vWF gene was constructed. The polymorphisms of vWF gene are very different between Chinese and Gaucasians. CONCLUSION: Combining to gene mutant in vWD patients, the use of site- directed mutagenesis and expression of vWF will help to understand the vWF function. The polymorphisms of vWF gene are useful marker in Chinese for carrier detection and prenatal diagnosis of vWD.

Humans↗
PubMed2000

Basic and clinical study on the antithrombotic mechanism of glycosaminoglycan extracted from sea cucumber.

OBJECTIVE: To investigate the antithrombotic mechanism of glycosaminoglycan (GAG) extracted from sea cucumber. METHODS: We studied the effects of GAG on the coagulant pathway by measuring cloting time. The antithrombin mechanism of GAG was checked by assaying its effects on the thrombin activity in normal human pooled plasma, purified human heparin cofactor II system and antithrombin III system. The effects of GAG on the assembly, dispersion, and structure of fibrin gels as well as on the activity of plasmin were studied by means of turbidimetry, electron microscopy, and chromogenic substrate assay. We studied the effect of GAG on the expression and transcription of tissue factor (TF) and thrombomodulin (TM) in LPS (lipopolysaccharide)-stimulated human umbilical vein endothelial cells (HUVECs), and used heparin as a control. HUVECs were treated with different concentrations of GAG (1 microgram/ml, 5 micrograms/ml, and 10 micrograms/ml respectively) and 5 micrograms/ml heparin as a control together with LPS (1 microgram/ml). After incubation for 6 hours, TF and TM were investigated by ELISA and the mRNA study was carried out by RT-PCR. In a clinical trail, a series of variables were observed before and after treatment with GAG in patients recovering from cerebral ischemic stroke or suffering from ischemic heart disease. RESULTS: The TT and APTT were significantly prolonged by GAG (0.1 microgram/ml). GAG inhibited thrombin activity in the presence of HCII with a second order rate constant of 1.14 x 10(7) m-1.min-1, which was 4.6 times higher than that of ATIII. GAG significantly inhibited the polymerization of fibrin monomer and enhanced the activity of plasmin in a concentration dependent manner. GAG could impair TF mRNA expression and up-regulate TM mRNA expression. The result of clinical trail showed that the fat metabolism was enhanced in addition to the anticoagulant and the blood viscosity reducing effects. No side-effect was found. CONCLUSIONS: GAG mainly affected on the intrinsic pathway of blood coagulation. GAG was similar to dermatan sulfate both in the efficiency and in the mechanism of antithrombin. The acceleration of colt lysis by GAG depended on its ability to increase the activity of plasmin, to inhibit the polymerizing of fibrin monomer, and consequently, to alter the architecture of the fibrin net work. This effect on HUVECs appears to be at a transcriptional level and might be relevant for the antithrombotic action of GAG. GAG possess anticoagulant activity in vivo and it is a promising drug for antithrombotic therapy.

Animals↗
PubMed2000

Effect of immunoglobulin G from patients with Graves' ophthalmopathy and interferon gamma in intercellular adhesion molecule-1 and human leucocyte antigen-DR expression in human retroocular fibroblasts.

OBJECTIVE: To detect the expression of intercellular adhesion molecule-1 (ICAM-1) and human leucocyte antigen-DR (HLA-DR) on retroocular fibroblasts (RFs) by immunoglobulin G (IgG) from patients with Graves' ophthalmopathy (GO) and interferon gamma (IFN-gamma) and to study the possible mechanism of humoral immunity and cellular immunity in the pathogenesis of GO. METHODS: Purified IgG was obtained from 23 patients (GO 10, Graves' disease 9, toxic multinodular goiter 4) and 8 normal persons. Cytokine IFN-gamma and thyroid stimulating hormone (TSH) were incubated with normal human RF cultured in vitro. Antigen expression on RFs induced by stimulators was examined using immunofluoresence staining and a flow cytometer. RESULTS: RFs spontaneously expressed ICAM-1, but did not express HLA-DR. All IgGs from patients with GO and other thyroid diseases as well as from normal persons could not stimulate the expression of ICAM-1 on RFs. IFN-gamma and TSH significantly enhanced the expression of ICAM-1 in dose-dependent manner (P < 0.05). Only IFN-gamma could stimulate RFs to express HLA-DR (P < 0.05). CONCLUSIONS: IgG from patients with GO did not stimulate the expression of ICAM-1 and HLA-DR on the surface of cultured normal human RFs. IFN-gamma was the important factor for intiating and promoting autoimmune reactions in GO. We need to pay more attention to TSH, as it may possibly play a promoting role in the pathogenesis in GO.

Adult↗
PubMed2000

Transient retinal ischemia-reperfusion in rats.

OBJECTIVE: To investigate the effect of transient ischemia-reperfusion on the retina in rats. METHODS: Retinal ischemia-reperfusion was induced in rats by increasing the intraocular pressure. After 1 or 5 minutes of ischemia, retinal neuronal cell death at different periods of reperfusion was studied using the TdT-deoxynucleotide terminal nick-end labeling (TUNEL) method and light microscopy. Retinal IL-1 beta and TNF alpha were quantified by an enzyme-linked immunosorbent assay (ELISA). RESULTS: A few migrating leukocytes were noticed in the retina after transient retinal ischemia-reperfusion. Rare TUNEL-positive (T+) cells were noticed in the outer granular layer or the rod and cone layer, and not in ganglion cell layer in control eyes, but they were significantly increased in the outer granular layer, the inner granular layer, and ganglion cell layer in the eyes treated with 1 or 5 minutes of retinal ischemia-reperfusion (P < 0.05). Retinal IL-1 beta was significantly increased at 6 hours after reperfusion in the eyes treated with 1 or 5 minutes ischemia over the control eyes (P < 0.05), but retinal TNF alpha was not significantly increased (P > 0.05). CONCLUSION: Transient retinal ischemia-reperfusion for only 1 or 5 minutes of ischemia can induce the upregulation of retinal IL-1 beta and apoptosis of retinal neuronal cells. This kind of apoptosis in individual cells, however, was not sufficient to affect the whole retinal function.

Animals↗
PubMed2000

Intravesical immunotoxin as adjuvant therapy to prevent the recurrence of bladder cancer.

OBJECTIVE: To assess the intravesical application of immunotoxin as adjuvant therapy to prevent recurrence after tumor resection in bladder cancer patients. METHODS: An anti-human immunotoxin against bladder carcinoma, BDI-1-RT, was prepared and its in vitro targeting cytotoxicity estimated. The immunoreactivity of BDI-1-RT with human bladder cancer tissue of different grades and stages was detected by immunohistochemical analysis. After safety test, intravesical administration of BDI-1-RT was performed in 31 patients while mitomycin C (MMC) was used in 36 patients serving as a control group. The recurrence rates and side effects in both groups were recorded. In addition, the development of human anti-mouse antibodies (HAMA) was determined by ELISA, to assess the potential safety of this immunotoxin. RESULTS: In our study, BDI-1-RT had immunoreactivity with 81.6% of bladder transitional cell carcinomas. The immunoreactivity of BDI-1-RT correlated with tumor grade. High-grade carcinoma had stronger staining than low-grade (P < 0.05). There was no significant difference between the BDI-1-RT group (10%) and MMC group (19.3%) in recurrence rate (P > 0.05). Side effects, including systemic and local, were more frequent in the MMC group (11 of 36 patients versus 2 of 31, P < 0.05). HAMA was not detected in any of 7 patients. CONCLUSION: Immunotoxin may have considerable potential in the prophylaxis of bladder transition cell carcinoma.

Administration, Intravesical↗
PubMed2000

[Susceptibility to lung cancer in Chinese is associated with genetic polymorphism in cytochrome P4502E1].

OBJECTIVE: To investigate the genetic polymorphism of cytochrome P4502E1 (CYP2E1) as a susceptibility factor for lung cancer in Chinese population. METHODS: The genotype frequencies of RsaI restriction fragment length polymorphisms were analyzed in 92 lung cancer cases and 137 frequency-matched normal controls. RESULTS: The CYP2E1 c1/c1 genotype was found in 72.8% of lung cancer cases, which was significantly higher (P < 0.01) than that in controls (54.7%). By multivariate analysis, this genotype was found to be associated with a 2.5-fold increased risk of lung cancer (adjusted OR 2.5, 95% CI 1.8-3.8). Stratified analysis suggested an interaction between CYP2E1 c1/c1 genotype and cigarette smoking. The odds ratio (OR) for the CYP2E1 c1/c1 genotype, cigarette smoking and both factors combined was 3.9 (95% CI 1.1-15.2), 4.1 (95% CI 1.1-15.9) and 7.9 (95% CI 2.4-29.4), respectively. The interaction between CYP2E1 c1/c1 genotype and pack-years of cigarette smoking followed the same pattern, with a markedly increased risk in the heaviest smokers. CONCLUSION: The CYP2E1 c1/c1 genotype is a susceptibility factor for development of lung cancer in Chinese and there is an apparent gene-environment interaction between the susceptible genotype and cigarette smoking.

Aged↗
PubMed2000

[Changes on the protein kinase C activity of alveolar macrophages in patients with idiopathic pulmonary fibrosis].

OBJECTIVE: To study the changes on protein kinase C(PKC) activity of alveolar macrophages (AM) in patients with idiopathic pulmonary fibrosis(IPF). METHOD: The PKC activity of AM in 9 healthy volunteers and 15 patients with IPF was investigated by radioactivity measuring. RESULTS: The total, cytosolic and particulate fraction PKC activity of AM in bronchoalveolar lavage fluid(BALF) from patients with IPF were higher than those from control group(P < 0.01 and P < 0.05). The total and the membrane fraction PKC activity had positive correlation with the number of cells in BALF(r = 0.8135, P < 0.01 and r = 0.5917, P < 0.05) respectively. CONCLUSION: As a bypass of transmembrane signal transduction, PKC was suggested to be involved in the development of IPF.

Adult↗
PubMed2000

[Comparison of effect of the mandible setbacked by SSRO and IVRO on gnathostomatic system].

OBJECTIVE: To compare the effect of the mandible setbacked by sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) on gnathostomatic system. METHODS: 27 cases with mandibular prognathism were treated, 16 received SSRO and 11 IVRO. Their occlusal force and masticatory efficiency were measured preoperatively and at 3 and 6 months after operation. The condylar positions were assessed by radiography before surgery and at 6 months postoperatively. RESULTS: In three months postoperatively, the occlusal force and masticatory efficiency of IVRO group was decreased more than that of SSRO group. At six months postoperatively, the occlusal force and masticatory efficiency of SSRO group recovered quicker than IVRO group and better than that of before operation. In IVRO group, the occlusal force approached the preoperative level, the masticatory efficiency was better than preoperative value. 26/32 (81.2%) condyles were relatively retropositioned in SSRO group, 14/22 (63.6%) condyles were relatively forward positioned in IVRO group. CONCLUSIONS: The function recovery time after surgery was shorter in SSRO group. The masticator muscles were detached in varying degree and the bone segments healed slowly, the effect on gnathostomatic system was greater and recovery time after surgery was longer in the IVRO group.

Adult↗
PubMed2000

[Carcinogenesis effects of gastric and duodenal refluxate on esophageal mucosa].

OBJECTIVE: To investigate the effects of different refluxant on esophageal carcinogenesis in rats. METHODS: The animal models of gastroesophageal reflux (G), duodenoesophageal reflux (D) and duodenogastroesophageal reflux (DG) and no reflux as control (C) were made by operations. The rats in all of the groups were given carcinogen (methyl-n-amyl nitrosamine, MANA). They were killed at 4, 20, 26, 40-week, then their esophagi were taken to the morphologic study and the expression of p53, cyclinD(1), CDK(4) studied with immunohistochemical studies. RESULTS: At 4-week without carcinogen, most of rats in reflux groups displayed evidence of esophageal mucosal injury. The degree of mucosal injury in D group was greater than that in DG which was greater than that in G; and became severity with the time. At 40 weeks, the incidences of papillomas in group D, DG, G were 94.7%, 95.2%, 70.5%, respectively. All of them compared to the group C (38.5%) were significant difference. Only in both D and DG group, there were 24 with esophageal columnar metaplasia, 20 with dysplasia and 11 with cancer. The overexpression of p53, CDK(4), cyclin D(1) was seen in D and DG groups, while in G group, the overexpression of p53 and cyclin D(1) were seen only. CONCLUSION: Both of gastric juice and duodenal contents reflux can promote tumourgenesis of MANA on esophagi by changing the expression of cell cycle-related protein. The effect of duodenal contents is stronger. It may play an important role in tumourgenesis of gastroesophageal reflux disease.

Animals↗