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Biomedical subjects

Yan Li

Publications and source records attributed to Yan Li.

At least 631 records · Page 35Linked to original sources
PubMed2003

[Study on the application of bio-heat transfer science to the quantitative analysis of tongue inspection].

OBJECTIVE: To research the mechanism of the tongue inspection in traditional Chinese medicine and to study the special relationship between temperature distribution of the tongue and the tongue color. METHODS: The temperature field of human and pig's tongue was measured by infrared thermal vision system and thermal-couple probe. The blood perfusion rates in the human tongue and the pig's tongue were obtained with laser Doppler rheometer and CBI-8000 physiology research system. The temperature field of the profile of tongue was computed by numerical method. RESULTS: The quantitative curve of the temperature distribution on the surface of tongue and the relationship between temperature and blood perfusion rate were obtained. And the temperature in the profile of tongue was obtained by finite element method. CONCLUSION: The research involves that the different tongue color can reflect different tongue temperature and blood perfusion rate. This proved that it is acceptable to apply the bio-heat transfer theory to the tongue inspection research. The results provided a new method to research the tongue inspection in traditional Chinese medicine.

Animals↗
PubMed2003

Antiproliferative effect of octreotide on gastric cancer cells mediated by inhibition of Akt/PKB and telomerase.

AIM: To investigate the antiproliferative effect of octreotide, a long-acting analogue of somatostatin, on gastric cancer cell line SGC7901 and its possible molecular mechanisms. METHODS: Gastric cancer cell line SGC7901 employed in the study was treated with 0.008, 0.04, 0.2, 1, 5 and 25 microg.ml(-1) of octreotide respectively for 24 h to evaluate the antiproliferative effect of somatostatin analog on the tumor cells by MTT assay method. To elucidate the underlying mechanism, the cells were exposed to 1 microg.ml(-1) of octreotide for 0, 12, 24 and 48 h, when their Akt/PKB and telomerase activities were respectively determined using PCR-ELSIA and nonradioactive protein kinase assay protocols. The same experimental procedures were also performed in the control cells that were treated with corresponding vehicles instead of somatostatin analog. RESULTS: After exposed to octreotide for 24 h at the concentrations of more than 1 microg.ml(-1), SGC7901 cells exhibited a dose-dependent inhibition of growth with the inhibiting rate to be as high as 34.66% when 25 microg.ml(-1) of octreotide was applied. The Akt/PKB and telomerase activity of SGC7901 cells was significantly inhibited when the cells were exposed to 1 microg.ml(-1) of octreotide for 12, 24 and 48 h compared with that of their control counterparts (P<0.01), both of which exhibited in a time-dependent manner. CONCLUSION: The antiproliferative effect of octreotide on SGC7901 cells might be mediated by the inhibition of Akt/PKB and telomerase.

Antineoplastic Agents, Hormonal↗
PubMed2003

Epoxide hydrolase Tyr113His polymorphism is not associated with susceptibility to esophageal squamous cell carcinoma in population of North China.

AIM: To investigate the possible association of microsomal epoxide hydrolase (mEH) Tyr113His polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC) in a population of North China. METHODS: The mEH Tyr113His genotypes were determined by polymerase-chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis in 257 patients with esophageal squamous cell carcinoma (ESCC) and 252 healthy subjects as a control group. RESULTS: The frequencies for Tyr and His alleles were 44.2%, 55.8% in ESCC patients, and 44.0% and 56.0% in healthy subjects, respectively. No statistic difference in allele distribution was observed between ESCC patients and controls (chi2=0.008, P=0.929). The overall genotype distribution difference was not observed between cancer cases and controls (chi2=2.116, P=0.347). Compared with Tyr/Tyr genotype, neither His/His genotype nor in combination with Tyr/His genotype significantly modified the risk of the development of ESCC, the adjusted odds ratio was 1.076 (95% CI=0.850-1.361) and 0.756 (95% CI=0.493-1.157), respectively. When stratified for sex, age, smoking status and family history of upper gastrointestinal cancer, His/His genotype alone or in combination with Tyr/His genotype also did not show any significant influence on the risk of developing ESCC. CONCLUSION: MEH Tyr113His polymorphism may not be used as a stratification marker in screening individuals at a high risk of ESCC.

Adult↗
PubMed2003

Effects of long-term tea polyphenols consumption on hepatic microsomal drug-metabolizing enzymes and liver function in Wistar rats.

AIM: To investigate the effects of long-term tea polyphenols (TPs) consumption on hepatic microsomal drug-metabolizing enzymes and liver function in rats. METHODS: TPs were administered intragastrically to rats at the doses of 833 mg.kg(-1).d(-1) (n=20) and 83.3 mg.kg(-1).d(-1) (n=20) respectively for six months. Controlled group (n=20) was given same volume of saline solution. Then the contents of cytochrome P450, b5, enzyme activities of aminopyrine N-demethylase (ADM), glutathione S-transferase (GST) and the biochemical liver function of serum were determined. RESULTS: The contents of cytochrome P450 and b5 in the livers of male rats in high dose groups (respectively 2.66 +/- 0.55, 10.43 +/- 2.78 nmol.mg MS pro(-1)) were significantly increased compared with the control group (1.08 +/- 1.04, 5.51 +/- 2.98 nmol.mg MS pro(-1); P<0.01, respectively). The enzymatic activities of ADM in the livers of female rats in high dose groups (0.91 +/- 0.08 mmol.mg MS pro(-1)min(-1)) were increased compared with the control group (0.82 +/- 0.08 mmol.mg MS pro(-1).min(-1); P<0.05). The GST activity was unchanged in all treated groups, and the function of liver was not obviously changed. CONCLUSION: The antidotal capability of rats' livers can be significantly improved after long-term consumption of TPs. There are differences in changes of drug-metabolizing enzymes between the sexes induced by TPs and normal condition.

Aminopyrine N-Demethylase↗
PubMed2003

Expression, purification and serological analysis of hepatocellular carcinoma associated antigen HCA587 in insect cells.

AIM: In order to assess hepatocellular carcinoma associated antigen HCA587 as a potential target for immunotherapy, the Bac-to-Bac expression system was used to express recombinant protein HCA587 in insect cells. METHODS: The cDNA encoding HCA587 gene was cloned into donor vector pFasBacHtb and recombinant pFasBac Htb-587 was transformed into competent cells DH10Bac. Recombinant Bacmid-587 was transfected into Sf9 insect cells using CELLFECTIN, Recombinant HCA587 protein was produced in Sf9 insect cells after infection with recombinant baculovirus, and was purified using Ni-NTA resin. Sera from HCC patients were also screened using recombinant protein HCA587. RESULTS: The molecular weight of the recombinant protein HCA587 expressed in insect cells was approximately 43kd. Western blot results proved the recombinant protein HCA587 had the similar antigenicity with its native counterpart. Serological analysis told that the rate of seroreactivity to HCA587 was not high in HCC patients. CONCLUSION: The recombinant protein HCA587 was successfully expressed and purified using Bac-to-Bac expression system. It paved the way for generation of specific antibody and investigation of immunohistochemical analysis and immune responses of HCC in the future.

Animals↗
PubMed2003

NQO1 C609T polymorphism associated with esophageal cancer and gastric cardiac carcinoma in North China.

AIM: To investigate the association of the NQO1 (C609T) polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) in North China. METHODS: The NQO1 C609T genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in 317 cancer patients (193 ESCC and 124 GCA) and 165 unrelated healthy controls. RESULTS: The NQO1 C609T C/C, C/T and T/T genotype frequency among healthy controls was 31.5 %, 52.1 % and 16.4 % respectively. The NQO1 T/T genotype frequency among ESCC patients (25.9 %) was significantly higher than that among healthy controls (chi(2)=4.79, P=0.028). The NQO1 T/T genotype significantly increased the risk for developing ESCC compared with the combination of C/C and C/T genotypes, with an age, sex and smoking status adjusted odds ratio (OR) of 1.78 (1.04-2.98). This increased susceptibility was pronounced in ESCC patients with family histories of upper gastrointestinal cancers (UGIC) (adjusted OR=2.20, 95 % CI=1.18-3.98). Similarly, the susceptibility of the NQO1 T/T genotype to GCA development was also observed among patients with family histories of UGIC, with an adjusted odds ratio of 2.55 (95 % CI=1.21-5.23), whereas no difference in NQO1 genotype distribution was shown among patients without family histories of UGIC. CONCLUSION: Determination of the NQO1 C609T genotype may be used as a stratification marker to predicate the individuals at high risk for developing ESCC and GCA in North China.

Adenocarcinoma↗
PubMed2003

Autologous cell transplantation and cardiac tissue engineering: potential applications in heart failure.

The promising concept of cell transplantation and cardiac tissue engineering has been developed in the last few years and focused on strategies attempting to replace dysfunctional, necrotic, and/or apoptotic cardiomyocytes with new cells of mesodermal origin. Transplantation of autologous cells minimizes the risk of neoplasia and avoids immune rejection associated with allogenic or xenogenic cells and recent data hold enormous hopes for short term clinical practices. Tissue engineering represents another promising approach that makes possible the creation of new functional tissues to replace the lost or failing one. Three-dimensional polymeric scaffolds provide the mechanical support for the candidate cells until the formation of cardiac-like tissue prior to surgical repair of the infarcted myocardium. For ultimate clinical applications, further investigations have to select the appropriate cell types, to determine the sufficient number of grafted cells and to provide the long term evaluation of these strategies in the global improvements of cardiac function (neoangiogenesis, synchronous contraction and extracellular matrix remodelling).

Biocompatible Materials↗
PubMed2003

[Biological analysis of a novel gene related with interleukin-6].

OBJECTIVE: To understand the action mechanism of interleukin (IL)-6 through investigation of its related genes. METHODS: Using electronic cloning with IL-6-related expressed sequence tags (ESTs), a novel gene at its full length of 924 bp was acquired. Reverse transcriptase-PCR method was subsequently employed to amplify the cDNA of this gene from the total RNA of human U937 cells, which were previously activated with 100 ng/ml IL-6 for 8 h. The fragment was then ligated into the pGEM-Teasy vector and sequence analysis was conducted. RESULT: The whole cDNA gene was successfully fished. CONCLUSION: Electronic cloning technology can be instrumental in identifying novel genes.

Amino Acid Sequence↗
PubMed2003

Differentiation of endothelial progenitor cells from human umbilical cord blood CD 34+ cells in vitro.

AIM: To study the time course of the expression of stem cell marker and endothelial cell markers on human cord blood CD34+ cells during in vitro differentiation process of endothelial progenitor cells (EPC). METHODS: CD34+ cells were selected and enriched from human cord blood by magnetically activated cell sorting (MACS), and cultured in dishes coated with or without fibronectin (Fn). Endothelial cells were identified by staining the cells with anti Flk-1 and vWF antibodies. The percentage of AC133+ cells in adherent CD34+ cell population was analyzed by fluorescence-activated cell sorting (FACS). RESULTS: The expression of Flk-1 and vWF on adherent CD34+ cells increased during the culture time, with 27.0 % positive for Flk-1 and negative for vWF at d 3, and 100 % positive for both Flk-1 and vWF at d 7. When cells were cultured in Fn-treated dishes, the percentages of Flk-1 and vWF positive cells increased to 34 % and 47 %, respectively at d 3, and 100 % at d 7. In contrast, the percentages of AC133+ cells among the adherent cell population decreased rapidly, and similar changes occurred in cells cultured in the presence of Fn. CONCLUSION: The gradual appearance of endothelial cell markers and the disappearance of stem cell marker characterized the in vitro differentiation of endothelial progenitor cells. Fibronectin accelerated the differentiation process of EPC.

AC133 Antigen↗
PubMed2003

[The evaluation of LFH or LFPH in the treatment of advanced cancer of gastric cardia and colorectal cancer].

OBJECTIVE: To evaluate the therapeutic effects of hydroxycamptothecin (H) combined with leucovorin (L), fluorouracil (F) and cisplatin (P) on advanced cancer of gastric cardia and colorectal cancer. METHODS: Sixty-five patients with advanced cancer of gastric cardia or colorectal cancer were treated by LFH or LFPH regimen. All patients completed four cycles of treatment, in 21 days per cycle. RESULTS: The overall response rate (RR) was 26.2% (17/65) with partial response (PR) in 17 patients, stable disease (SD) in 31 and progressive disease (PD) in 17. The clinical benefit response rate (CR + PR + SD) was 73.8% (48/65). The RR were 32.3% (10/31) for untreated patients and 20.6% (7/34) for retreated patients. The stable rate was 47.7% (31/65). The RR of patients with cancer of gastric cardia were 33.3% (5/15) for untreated treatment and 29.4% (5/17) for retreated ones. Median survival time (MST) was 10 months. Median time to progression (MTTP) was 8 months. Grade 3 - 4 toxicities were stomatitis (10.8%), nausea and vomiting (12.3%) and leukopenia (6.2%). Most patients (> 80%) developed Grade 1 - 2 alopecia. CONCLUSION: The regimen of HCPT combined with LV, 5-Fu and DDP appears to be an effective and tolerable therapeutic option for advanced cancer of gastric cardia and colorectal cancer, especially for the former and retreated patients, giving a satisfactory stable rate though not very high.

Adult↗
PubMed2003

[Microscopy identification of Caltha palustris L. var. membranacea Turcz].

OBJECTIVE: To identify Caltha palustris L. var. membranacea Turcz. METHODS: Morphological and histological identification. RESULTS: There are crystals in root and mesophyll from Caltha palustris L. var. membrancea Turcz.. Anomocytic type stomata are visible. CONCLUSION: Above mentioned characters can be used for the identification of Caltha palustris L. var. membranacea Turcz.

Calcium Oxalate↗
PubMed2003

[Comparison of corneal wound healing of photorefractive keratectomy and laser in situ keratomileusis in rabbits].

OBJECTIVE: To compare effects of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) on the cornea and corneal wound healing and to investigate the possible mechanism of corneal haze and myopic regression histopathologically. METHODS: Twenty-four New Zealand white rabbits were allocated randomly to correct -4.00 and -8.00 diopters and were operated with PRK on right eyes and LASIK on left eyes. At 10 days and 1, 3, and 6 months, corneal haze was observed, refraction was evaluated, and 3 rabbits were randomly selected for each time point to be enucleated, and corneas to be bisected. One half of each cornea was evaluated using transmission electron microscopy, and the other half was evaluated using either light microscopy or immunohistochemical staining for collagen type III, IV, fibronectin (FN) and transforming growth factor-beta(1) (TGF-beta(1)). RESULTS: Different degrees of corneal haze and myopic regression were observed after PRK: the higher the desired myopic correction, the heavier the haze. Corneal wound healing response was greater and lasted longer after PRK than after LASIK. Various pathological findings such as epithelial hyperplasia, basal membrane reforming and extracellular matrix deposits were found in the ablation zone and repair mechanisms were still active at 6 months after PRK. Whereas after LASIK, the interface between the flap and stromal bed was transparent except for growing epithelial plugs and lightly proliferating stroma coinciding with the flap margins. After both PRK and LASIK, all corneal cell types were consistently positive for TGF-beta(1) antibody during the corneal wound healing time. TGF-beta(1) antibody positivity decreased as the wound healing approached completion. The histopathological changes of corneal haze and myopic regression are as follows: epithelial hyperplasia, basal membrane immaturity, anterior stromal keratocyte increase and activity, new collagen III production and irregular arrangement thereof, and FN deposition in the extracellular matrix under the epithelium. CONCLUSIONS: Compared with PRK, LASIK ensures refractive stability with quick wound healing and minimal tissue proliferation resulting in a more promising corneal refractive surgery to correct myopia, especially more severe cases of myopia. The corneal wound healing especially the stromal healing is the key to the cause of haze and myopic regression. TGF-beta(1) may be involved in scar formation during wound healing by stimulating expression of collagen III and FN and is believed to be an important regulating factor.

Animals↗
PubMed2003

[Expression of survivin gene and its relation with the expression of bcl-2 and bax protein in epithelial ovarian cancer].

OBJECTIVE: To study the expression of apoptosis related gene survivin and its relation with expression of bcl-2, bax protein in epithelial ovarian cancer. METHODS: Expression of survivin gene was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 35 cases of epithelial ovarian cancer, and compared with that in 10 cases of borderline cancer, 10 cases of benign tumors and 10 cases of normal tissue. Expression of bcl-2 and bax was detected by immunohistochemistry streptomycin-avidin-biotin-peroxidase complex (SABC) method, and correlation between them was analyzed. RESULTS: Expression of survivin gene was detected in a significantly greater proportion in epithelial ovarian cancer and borderline tumors than benign tumors and normal tissue. There was no relationship between survivin gene expression and FIGO stage, histologic grade, pathological type and lymphatic metastasis. Expression of bcl-2 and bax protein was positively and negatively correlated with expression of survivin gene respectively. CONCLUSION: survivin gene may play an important role in pathogenesis of ovarian cancer, apoptosis related gene bcl-2 may have a synergic role and bax have an antagonistic role with survivin gene in formation and progression of ovarian cancer.

Adolescent↗
PubMed2003

[Non-diabetic renal disease in type II diabetes mellitus].

OBJECTIVE: Several studies have suggested that non-diabetic renal disease (NDRD) was common among non-insulin dependent diabetes mellitus (NIDDM) patients with renal involvement. METHODS: The prevalence of NDRD among Chinese NIDDM population in PUMC hospital center was retrospectively studied. Renal biopsy specimens were evaluated with light-, immunofluorescence- and electron-microscopy. The cohort consisted of 33 NIDDM patients who received renal biopsy. RESULTS: Patients with both isolated diabetic nephropathy (DN, n = 7) and NDRD (n = 22) had comparable duration of DM, creatinine clearance, serum creatinine, albumin and 24 hours proteinuria, as well as incidences of retinopathy, neuropathy and hypertension. Significantly more patients with NDRD had haematuria (P = 0.030) or non-nephrotic proteinuria (P = 0.016). IgA nephropathy accounted for 40.9% of the NDRD identified. CONCLUSIONS: In this study, haematuria and non-nephrotic proteinuria predicted the presence of NDRD among NIDDM patients complicated with renal disease. IgA nephropathy is the most frequent type of NDRD in Chinese.

Adult↗
PubMed2003

[p53 gene polymorphism with susceptibility to esophageal cancer and lung cancer in Chinese population].

OBJECTIVE: To investigate the association of p53 codon 72 polymorphism with susceptibility to esophageal cancer and lung cancer in the northern Chinese population. METHODS: p53 codon 72 genotyping was performed by amplifying DNA fragments with sequence specific primers among 173 patients with esophageal squamous cell carcinoma, 98 with non-small cell lung carcinoma as well as 136 healthy controls. RESULTS: No significant difference of p53 allelotype and genotype distribution was observed between esophageal cancer and lung cancer patients. The Pro allele frequency was significantly higher among esophageal cancer and lung cancer patients than among healthy controls (P value was 0.024 and 0.027 respectively). There were no significant differences in Pro/Arg and Arg/Arg genotype frequency among cancer patients and healthy controls (P > 0.05). However, the Pro/Pro genotype frequency was significantly higher among esophageal cancer and lung cancer patients than among healthy controls (P value was 0.041 and 0.026 respectively). The risk of Pro homozygotes for both esophageal cancer and lung cancer was about 2 times against Arg homozygotes with adjusted odds ratio of 2.12 (95% CI = 1.13 - 4.01) and 2.30 (95% CI = 1.13 - 4.93), respectively. There was no interaction between p53 Pro/Pro genotype and smoking status to the risk for esophageal cancer and lung cancer. CONCLUSION: In the northern Chinese population, p53 Pro/Pro genotype is an independent risk factor for both esophageal cancer and lung cancer. The possible common genetic basis of the development of these two cancers is suggested by this study.

Alleles↗
PubMed2003

[Analysis of genetic structure of Magnaporthe grisea in the fields of different rice varieties].

The DNA of 251 Magnaporthe grisea isolates from Shiping County, which originated from monoculture and mixture fields, was extracted and amplified by rep-PCR which primer was from palindromes Pot2 of Magnaporthe grisea. The result showed that all isolates were amplified 9-17 DNA bands, the size was about from 400 bp to 23 kb, but mainly between 5-10 kb. 65% bands were polymorphism bands, and 35% were the same bands. Genetic structures of Magnaporthe grisea in the different rice varieties fields were compared by clustering analysis. The complexions of isolates genetic lineages were related to culture patterns. There were more genetic lineages in mixture field than in monoculture one. The dominant lineages were not distinct in mixture field. The result proved that biodiversity might provide a convincing basis for the steady selection of rice variety to pathogen.

Genetic Structures↗
PubMed2003

[Quantitative analysis of expression of TEY1 gene in liver cancer cells with different metastatic potential].

BACKGROUND & OBJECTIVE: The authors' previous study suggested there could be metastasis suppressor gene for liver cancer on human chromosome 8p. TEY1 was a newly discovered metastasis suppressor gene for prostate cancer located on human chromosome 8p. In order to explore whether TEY1 gene could be a metastasis suppressor gene for liver cancer, the expression of TEY1 was quantitated in liver cancer cell strains with different metastatic potential. METHODS: RNA was extracted from liver cancer cell strains, MHCC97-H, MHCC97-L, and HCCLM3, and normal liver cell line L02. The first strand cDNA was synthesized by reverse transcription, which was then used as the template to perform fluorescent quantitative polymerase chain reaction (FQ-PCR). The quantity of the expression of TEY1 gene was normalized by dividing with that of the housekeeping gene, GAPDH for each sample. One-way analysis of variance (ANOVA) was performed for the normalized values. RESULTS: The normalized initial cDNA concentrations of TEY1 in MHCC97-H, MHCC97-L, HCCLM3, and L02 were (3.57+/-2.62) x 10(-4), (5.02+/-1.95) x 10(-4), (2.82+/-0.78) x 10(-5), and (15.20+/-0.58) x 10(-4), respectively. The expression level of TEY1 in L02 was significantly different from those of liver cancer strains (P< 0.001). The expression level of TEY1 in HCCLM3 was also significantly different from those in MHCC97-H and MHCC97-L (P< 0.05). But there was no significant difference between MHCC97-H and MHCC97-L although the expression level of TEY1 gene in MHCC97-L was 1.4 times higher than that in MHCC97-H. CONCLUSION: The expression levels of TEY1 gene in liver cancer cells were negatively correlated with their different metastatic potentials; it could be conjectured that TEY1 may possibly be a metastasis suppressor gene for liver cancer.

Cell Line, Tumor↗