Biomedical subjects

W Li

Publications and source records attributed to W Li.

At least 469 records · Page 26Linked to original sources

PubMed2000

Aminoguanidine and the effects of modified LDL on cultured retinal capillary cells.

PURPOSE: Compared with normal low density lipoprotein (N-LDL), LDL minimally modified in vitro by glycation, minimal oxidation, or glycoxidation (G-, MO-, GO-LDL) decreases survival of cultured retinal capillary endothelial cells and pericytes. Similar modifications occurring in vivo in diabetes may contribute to retinopathy. The goal of this study was to determine whether low concentrations of aminoguanidine might prevent cytotoxic modification of LDL and/or protect retinal capillary cells from previously modified LDL. METHODS: Minimal in vitro modification of LDL (3 days, 37 degrees C) was achieved with glucose (0, 50 mM), under antioxidant conditions (for N-LDL, G-LDL), or under mild oxidant conditions (for MO-, GO-LDL) in the presence/absence of aminoguanidine (0, 1, 10, 100 microM). Glucose and aminoguanidine were then removed by dialysis. Confluent bovine retinal capillary endothelial cells (n = 13) and pericytes (n = 14) were exposed to LDL (100 mg/l) for 3 days, with and without aminoguanidine (100 microM) in media. Cell counts were determined by hemocytometer. RESULTS: A decrease in cell counts after exposure to modified compared with N-LDL was confirmed (P < 0.001) but was significantly mitigated if LDL had been modified in the presence of aminoguanidine (P < 0.001). Aminoguanidine was as effective at 1 microM as at the higher concentrations. Aminoguanidine (100 microM) present in culture media conferred no additional protection, and showed slight evidence of toxicity. Aminoguanidine present during LDL modification had no effect on measured glycation or oxidation products, or on LDL oxidizability. CONCLUSIONS: Very low concentrations of aminoguanidine mitigate toxicity of LDL exposed to stresses that simulate the diabetic environment. This action may contribute to the beneficial effects of aminoguanidine observed in experimental diabetic retinopathy.

Animals↗

PubMed2000

[Polymorphisms of four STRs and their associations with IDDM in Chinese Han population].

OBJECTIVE: To obtain the polymorphic data of short tandem repeat(STR) loci of D15S657, D11S1369, D6S2420 and D6S503 in Chinese Han population and to study the association of these four STR loci with insulin-dependent diabetes mellitus(IDDM). METHODS: The polymorphisms of the four STRs were studied by polymerase chain reaction-polyacrylamide gel electrophoresis(PCR-PAGE) followed by direct sequencing of PCR products in 105 normal Chinese Hans and 48 patients with IDDM. RESULTS: Seven alleles at D15S657 locus, 5 alleles at D11S1369 locus, 7 alleles at D6S2420 locus and 4 alleles at D6S503 locus were found. No deviation from Hardy-Weinberg equilibrium was observed. The heterozygosities of these loci were 0. 7524, 0.6000, 0.6286, 0.6571 and the polymorphic information contents(PIC) 0.7616, 0.4430, 0.5345 and 0.5932, respectively. The allele frequencies of allele A(5) at D15S657 locus, allele A(5) at D11S1369 locus and allele A(4) at D6S2420 locus were increased significantly in patients with IDDM, compared to those in the control group. CONCLUSION: The four STRs, used as genetic markers, were suitable for case-control study, forensic medicine identification and population genetic study. There is an association between the polymorphisms of D15S657, D11S1369, D6S2420 and IDDM.

Adult↗

PubMed2000

Signal transduction and biochemical targeting of ovarian carcinoma.

UNLABELLED: The purpose was to identify novel targets for the chemotherapy of ovarian carcinoma. METHODS: Assays were worked out to measure the activities of P1 kinase, PIP kinase and PLC in ovarian carcinoma samples and in OVCAR-5 cells and to compare the activities to those in normal ovaries. A method was also designed for measuring the concentration of the end product of signal transduction, IP3. RESULTS AND DISCUSSION: Signal transduction activity was markedly increased in ovarian cancer cells as shown by the increased steady-state activities of the three enzymes and the elevated concentrations of IP3. Inhibitors blocked activities of PI kinase (quercetin), PIP kinase (genistein), and lowered GTP concentration required for PLC (tiazofurin). Combinations of tiazofurin with quercetin, tiazofurin with genistein, and quercetin with genistein yielded a synergistic kill of ovarian cancer cells. Tiazofurin, quercetin and genistein are in various stages of clinical trials. CONCLUSION: The increased signal transduction activity provides novel, sensitive targets to chemotherapy in ovarian cancer cells.

Cell Survival↗

PubMed2000

[Effects of heparin on the growth, extracellular matrix and matrix metalloproteinase gene expression in rat hepatic stellate cells].

OBJECTIVE: To study the effects of heparin on the growth, extracellular matrix and matrix metalloproteinase (MMP) gene expression in rat hepatic stellate cells (HSC). METHODS: Activated HSC was treated by heparin or fetal calf serum without heparin. The cell growth was evaluated by actual cell count and BrdU-labelled immunocytochemical stain. The gene expressions of type I and IV procollagen, fibronectin, MMP-2 and membrane type matrix metalloproteinase (MT-MMP) were investigated by immunocytochemical stain and digoxigenin-labeled in situ hybridization technique, respectively. In addition, the gelatinase activity of MMP-2 was examined by zymography. RESULTS: Heparin could obviously reduce HSC growth, inhibit the synthesis of type I procollagen and fibronectin protein, and the gene expressions of type I procollagen, fibronectin and MT-MMP. The expressions of type IV procollagen, MMP-2 and MMP-2 activity were not affected by heparin. CONCLUSION: The results demonstrate that heparin can inhibit HSC proliferation, down-regulate interstitial collagen synthesis and inhibit MT-MMP gene expression.

Animals↗

PubMed2000

TCM treatment of diabetic hearing loss--an audiological and rheological observation.

35 cases (48 ears) of diabetic hearing loss were randomly assigned to 2 groups: the treatment group of 19 cases (25 ears) treated with drugs for nourishing the kidney-yin, invigorating blood circulation and removing blood stasis based on differentiation of symptoms and signs, and the control group of 16 cases (23 ears) treated with euglucon and other routine drugs. The results showed that the total effective rate for audition elevation in the treatment group was 52.0%, and that in the control group, 26.1%. In the treatment group, the rheological indexes were improved after treatment, the difference being very significant in comparison with those before treatment (P < 0.05 and P < 0.01); while in the control group, except the whole blood low shearing specific viscosity, all the other 4 indexes were not statistically significant before and after treatment (P > 0.05).

Adult↗

PubMed2000

[Isolation and characterization of promoters from Phanerochaete chrysosporium].

Promoter-probe vector pSUPV8 was used to clone promoters from Phanerochaete chrysosporium directly in Escherichia coli. Six hygromycin B-resistant recombinants were obtained and two inserted fragments of them were sequenced. The results indicated that they contain several sequences similar to eukaryotic cis regulatory elements. Only pCH6 could transform P. chrysosporium into hygromecin B resistance. PCR and dot hybridization analysis indicated that it was introduced into P. chrysosporium successfully and leaded to the HmB-resistance. The results demonstrated that HmB-resistant gene (hph) could be used as an ideal reporter gene for P. chrysosporium transformation.

Base Sequence↗

PubMed2000

[A study of sleep apnea monitoring method and instrument].

In this paper the fundamental principle and great significance of sleep apnea monitoring are introduced, and the status quo of this field at home and abroad is described. Several kinds of methods for sleep apnea monitorin are analyzed, and on this basis the authors have developed a cheap and portable sleep apnea monitoring instrument. Experiment results demonstrate that the instrument is of convenience, high accuracy and good performance.

Adult↗

PubMed2000

New approaches in the management of choroidal neovascular membrane in age-related macular degeneration.

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly population. The prevalence is reported to be 1.2-1.4% in several population-based epidemiological studies. Currently 25-30 million people worldwide are blind due to AMD. With the aging world population it is bound to increase significantly, and could become a significant public health problem in next two decades, with serious socio-economic implications. Several strategies are today available to treat the wet form of AMD, which is responsible for significant visual loss. These were until recently confined to laser photocoagulation, and subretinal surgery, but today two other modalities, namely, radiation and photodynamic therapy, are available. These treatment modalities however, are aimed at preservation of vision only, and not at reversing the process of the disease. Further research on antiangiogenic drugs and gene therapy could significantly help AMD patients.

Blindness↗

PubMed2000

[Diagnosis and management of Mycoplasma pneumonia with cold agglutinin disease].

OBJECTIVE: To study the Mycoplasma pneumonia (MP) with cold agglutinin disease (CAD) and inquire into its diagnosis and treatment. METHODS: 3 report of cases and literature were reviewed. RESULTS: Accompanying with hemolysis and microcirculatory retardation, 3 patients with acute respiratory infection were finally diagnosed MP with CAD. Antimicrobial therapy and plasmapheresis showed favorable effect. CONCLUSIONS: MP patients would be highly suspected to be associated with CAD, if accompanying with hemolysis and microcirculatory retardation. Laboratory examinations are helpful for diagnosis. On the basis of combined therapy, plasmapheresis is effective.

Adult↗

PubMed2000

[Expression of glycoprotein gene of the rabies virus 3aG strain by E-3 deleted adenovirus recombinant].

OBJECTIVE: To analyze Chinese rabies virus vaccine strain 3aG glycoprotein (GP) gene and further produce GP by E3-deleted human adenovirus recombinant. METHODS: Chinese rabies virus vaccine strain 3aG glycoprotein gene was cloned by RT-PCR and its sequence was determined by DNA sequencing. Cotransfection was performed to obtain adenovirus recombinant. The expressed glycoprotein was examined by ELISA and its immunogenicity was evaluated by testing neutralizing antibody level of mice inoculated with the recombinant virus. RESULTS: DNA sequencing showed that the open reading frame of GP gene contains 1,575 nucleotides and five of the deduced amino acids are different from the previous report. The recombinant adenovirus containing GP gene in E3 region was obtained by cotransfecting 293 cells and rounds of plaque purification. ELISA assay demonstrated that the GP gene can be efficiently expressed and rapid fluorescent focus inhibition test (RFFTT) showed it can also elicit GP specific neutralizing antibody. CONCLUSIONS: Chinese rabies virus vaccine strain 3aG glycoprotein was successfully expressed by E3-deleted human adenovirus recombinant and specific neutralizing antibody can be elicited in mice after immunization by the recombinant.

Adenovirus E3 Proteins↗

PubMed2000

[Discussion on the contribution of Thousand golden prescriptions to the art of tuina].

Thousand Golden Prescriptions, including Thousand Golden Prescriptions for Emergencies and Supplements to Thousand Golden Prescriptions is an important medical book containing the main medical achievements before the Tang dynasty. It attaches great attention to daily tuina for health-care, enriches its contents, and makes a description to the method of tuina for children, offering detailed materials for later ages with significant reference value, and makes an important contribution to the art of tuina.

China↗

PubMed2000

[A wintering habitat model for red crown crane].

A mathematical model was established based on GIS and RS to simulate and predict the habitat distribution of red crown crane(Grus japonensis) in Yancheng Biosphere Reserve, Jiangsu Province, China. The model was tested through calculating the match coefficience of observed and predicted presence/absence data, which was 72.63%, showing that the model could be used to reflect the habitat distribution of red crown crane.

Animals↗

PubMed2000

[A method for designing buffer zone in Yancheng Biosphere Reserve: taking red crown crane as objective species].

Social, economic, ecological and geomorphic factors are needed to be considered when designing the buffer zone of natural reserve. In this paper, the Analytic Hierarchy Process(AHP) was applied to design the width of buffer zone. Under considerating the influences in different sections around the reserve, different widths of the buffer zone were designed, and a case study was carried out in Yancheng Biosphere Reserve. The results showed that the proposed method was reasonable and practicable in designing the buffer zone of nature reserve.

Animals↗

PubMed2000

Effect of intravenous nitroglycerin on hemodynamics in infants and children with congestive heart failure.

OBJECTIVE: To understand the effect of intravenous nitroglycerin (NTG) on hemodynamics in infants and small children with congestive heart failure secondary to congenital cardiac defect of left to right shunt. METHODS: Heart rate, blood pressure and total peripheral resistance were monitored continuously. Echocardiography was used to measure ejection fraction, fractional shortening, end-diastolic volume index of left ventricle, pulmonary capillary wedge pressure, pulmonary artery mean pressure and left ventricular wall stress before the use and during 0.5, 1.0, 1.5, 2.5, and 5.0 micrograms.kg-1.min-1 dosages of nitroglycerin (NTG). RESULTS: There was no significant difference in the indexes of heart rate, blood pressure, ejection fraction and fractional shortening of left ventricle, stroke volume index, cardiac output index, end-diastolic volume index before the use and after the use of NTG. Pulmonary capillary wedge pressure decreased from 15.5 +/- 2.3 mm Hg before the use of NTG to 14.3 +/- 2.2 mm Hg after the use of 0.5 microgram.kg-1.min-1 NTG (P < 0.05), minimum to 12.3 +/- 2.4 mm Hg; left ventricular wall stress I, II and III decreased from 407 +/- 65 dyn.cm-2.10(3), 166 +/- 48 dyn.cm-2.10(3), 255 +/- 52 dyn.cm-2.10(3) to 357 +/- 75 dyn.cm-2.10(3), 136 +/- 48 dyn.cm-2.10(3), 218 +/- 52 dyn.cm-2.10(3) (P < 0.05), minimum to 321 +/- 50 dyn.cm-2.10(3), 114 +/- 42 dyn.cm-2.10(3), 187 +/- 42 dyn.cm-2.10(3), respectively. Total peripheral resistance and pulmonary artery mean pressure were decreased when the dosage of intravenous NTG was increased to above 2.5 micrograms.kg-1.min-1 (P < 0.05). There was no statistical difference in the above indexes of the different dosages. CONCLUSION: Congestive heart failure secondary to congenital cardiac defect of left to right shunt in infants and small children is the indication of using intravenous NTG which could improve hemodynamics. There was different selectivity in dosage between arterial and venous vasodilatation, and the change in hemodynamics was independent of dosage. The dosages of 0.5-1.0 microgram.kg-1.min-1 NTG are recommended when the decrease of cardiac preload is the main point of therapy of heart failure.

Dose-Response Relationship, Drug↗

PubMed2000

[Automatic modulation of refractoriness of His-Purkinje system during atrioventricular nodal reentrant tachycardia].

OBJECTIVE: To illustrate the automatic modulation of refractoriness of His-Purkinje system during atrioventricular nodal reentrant tachycardia (AVNRT) and to discuss the possible mechanisms. METHODS: Programmed electrical stimulations were performed in high right atrium (HRA) in 8 patients with AVNRT before ablation to induce tachycardia and electrocardiagraphic recordings were done synchronically when AVNRT appeared. RESULTS: All the patients had 2:1 atrioventricular (A-V) conduction when AVNRT began, 2 of whom were blocked below His bundle, 5 above His bundle and 1 unclear. After a duration of 14.03 +/- 10.03 s of 2:1 A-V conduction, 1:1 A-V conduction with bundle banch block appeared, 3 of which were right bundle branch block (RBBB), 3 left bundle branch block (LBBB), and 2 with both. Bundle branch block disappeared after a duration of 6.87 +/- 11.26 s. CONCLUSION: Effective refractory period (ERP) of His-Purkinje system at the beginning of AVNRT was modulated automatically within less than 30-60 s and thus facilitated nodal-ventricular conduction. The mechanism of this is electrical remodeling.

Adult↗

PubMed2000

Molecular cloning and protein expression of EC1-2 and EC3-4 epitopes of pemphigus vulgaris antigen.

OBJECTIVE: To clone and express EC1-2 and EC3-4 epitopes of PVA (pemphigus vulgaris antigen, desmoglein-3) in order to diagnose pemphigus and study the relationship between epitopes of PVA and anti-PVA antibody. METHODS: RNA was extracted from keratinocytes and the cDNA of epitopes EC1-2 and EC3-4 was synthesized by reverse transcription. Amplified genes of EC1-2 and EC3-4 were inserted into the expression plasmid, PGEX-4T-1, and transformed into E. coli BL21 by electric transduction. Recombinant fusion proteins of EC1-2 and EC3-4 epitopes were expressed by IPTG induction. These proteins were separated on SDS-PAGE gels and electroblotted to nitrocellulose to detect the anti-PVA antibody. RESULTS: The sequences of cloned EC1-2 and EC3-4 genes were identical to the sequence registered in PC/GENE. Expressed recombinant proteins reacted only to sera from patients with pemphigus vulgaris, not to sera from patients with bullous pemphigoid, systemic lupus erythematosus or normal persons. CONCLUSIONS: These recombinant proteins are very specific in antigenicity. This may provide a new method for the diagnosis of pemphigus vulgaris (PV) or the differential diagnosis of other bullous cutaneous diseases via patient sera. It is also helpful in understanding the relationship between adhesion molecules and the pathogenic mechanism of pemphigus vulgaris.

Autoantibodies↗

PubMed2000

Cerebral venous sinus thrombosis: a clinical study of 23 cases.

OBJECTIVE: To describe the etiologies, clinical features and diagnosis of cerebral venous sinus thrombosis. METHODS: We reviewed the records of 23 patients admitted with a documented diagnosis of cerebral venous sinus thrombosis from 1991 through 1999 in the Beijing Tiantan Hospital. RESULTS: Infection was the major condition associated with cerebral venous sinus thrombosis. Pseudotumor cerebri syndrome was the most common manifestation, while hemiplegia, seizure and unconsciousness may occur alone or in association. The diagnostic sensitivity of computed tomography (CT), magnetic resonance imaging (MRI) and digital subtract angiography (DSA) were 59%, 86% and 100%, respectively. The sensitivity of MRI with magnetic resonance angiography (MRA) reached 96%. CONCLUSION: As the clinical findings were found to be nonspecific, CT combined with DSA, or MRI with MRA turns out to be valuable for the early diagnosis of cerebral venous sinus thrombosis.

Adolescent↗

PubMed2000

[Double semitendinous reconstruction of posterior cruciate ligament with invasive mini-plate technique].

OBJECTIVE: To probe the clinical results of a new designed operation-double semitendinous reconstruction of posterior cruciate ligament (PCL) with invasive mini-plate. METHODS: The new surgical technique was performed on 28 patients with PCL deficient knee in our department from September 1994 to October 1997. Protection of popliteal nerves and blood vessels was emphasized in the operation, and the femoral and tibial tunnel placement was critical to the procedure's success. RESULTS: All patients were followed up 18 to 36 months, averaged 22 months, they gained stable knees. The knee function of 28 patients recovered to normal after the operation, 1 patients had a small range of limitation of the knee flexion, but no obvious dysfunction. CONCLUSION: Double semitendinous reconstruction of PCL with invasive mini-plate has advantages in the operated field exposure, adequate tibial and femoral fixation and excellent results in motion, stability and function of the knee after the operation.

Adolescent↗