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Biomedical subjects

Yan Li

Publications and source records attributed to Yan Li.

At least 541 records · Page 30Linked to original sources
PubMed2004

[Study on the polymorphism of interleukin-1 gene and the susceptibility to essential hypertension].

OBJECTIVE: To make investigations on the polymorphism of interleukin-1 (IL-1)gene in Chinese Han population, on its association with essential hypertension, and on the relationship between the genotype of IL-1 and susceptibility to essential hypertension. METHODS: The polymorphisms of IL-1 gene in Han population of Hubei province, including polymorphisms of IL-1alpha (-889C/T), IL-1beta (-511C/T),IL-1beta (+3953C/T), IL-1Ra(+8006T/C) and IL-1Ra (variable number of tandem repeat, VNTR), were analyzed by polymerase chain reaction (PCR) and a combination of PCR-restriction fragment length polymorphism methods in 152 patients with essential hypertension and 168 healthy controls. RESULTS: The polymorphism distributions of IL-1alpha (-889C/T), IL-1beta (+3953C/T), IL-1Ra (+8006T/C) and IL-1Ra (VNTR) showed no differences between the essential hypertension group and control group, but the IL-1beta (-511C/T) exhibited a significant difference between the two groups. CT genotype carriers were at increased risk for essential hypertension (OR=2.54, 95%CI: 1.41-4.58), compared with healthy controls. CONCLUSION: The polymorphism of promotor region -511C/T in IL-1beta gene is probably associated with the susceptibility to essential hypertension.

Aged↗
PubMed2004

[Study on thermo-sensitive intelligent targeting type drug carriers (I) porous membranes with grafted thermo-sensitive gates].

Thermo-responsive intelligent membranes with linear grafted poly(N-isopropylacrylamide) (PNIPAM) gates on the inner pore surface were prepared, and experiments were carried out on the thermo-responsive gating characteristics. Plasma-graft pore-filling polymerization was used to graft PNIPAM into the pore of the porous flat membranes. The experimental results showed that PNIPAM-grafted PVDF (PNIPAM-g-PVDF) membranes were featured with thermo-responsiveness due to the thermo-responsive swollen-shrunken property of PNIPAM chains grafted on the inner pore surface of the membrane. At temperatures below the lower critical solution temperature (LCST), the linear grafted PNIPAM chains on the inner pore surface were in the swollen state, and the pores in the membrane were closed; in contrast, the grafted PNIPAM chains were in the shrunken state at temperatures above the LCST, and therefore the pores in the membrane were open. The LCST of the thermo-sensitive gates could be adjusted by adding acrylamide (AAM) in the N-isopropylacrylamide (NIPAM) monomer solution, the LCST of the poly(NIPAM-co-AAM) gates increased simply with the increase of the AAM fraction.

Acrylic Resins↗
PubMed2004

[Association between tumor necrosis factor-beta polymorphisms and coronary heart disease in a Chinese population].

OBJECTIVE: To investigate the association between tumor necrosis factor-beta (TNF-beta) gene polymorphisms and coronary heart disease (CHD). METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequence specific primer-PCR (PCR-SSP) were used for the detection of TNF-beta genotype in 210 patients with CHD and 186 healthy controls. The serum TNF-beta levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: The frequencies of CC, CA and AA genotypes of C804A in patients and controls were 25.7% and 37.1%, 49.5% and 45.7%, 24.8% and 17.2%, respectively; there were statistically significant differences in the distributions of the genotypes (P<0.05) and the allele frequencies (P<0.05) between the two groups; the risk of suffering from CHD in those of AA and CA genotypes was 1.704 times that in those of CC genotype (OR=1.704, 95%CI: 1.109-2.617). However, there was no significant difference in the distribution of the genotype of G252A between the patients and controls, though significant difference was seen between the subgroups of the CHD group. The serum TNF-beta and high sensitive C-reactive protein (hsCRP) levels of the patients were significantly higher than those of the controls (P<0.05); however, there were no significant differences in regard to different TNF-beta genotypes among the patients and controls respectively. CONCLUSION: The single nucleotide polymorphism (SNP) at position 804 in the exon 3 of TNF-beta gene is associated with CHD and the allele A may be a risk factor for CHD in Chinese. The polymorphism of G252A may not play an important role in the pathogenesis of CHD.

Aged↗
PubMed2004

[Intoxication induced by unsymmetrical dimethylhydrazine: characteristics and mechanism of its acute and chronic injuries].

OBJECTIVE: To investigate the characteristics and mechanism of the acute and chronic injuries induced by unsymmetrical dimethylhydrazine (UDMH). METHODS: A total of 128 male rats were randomly divided into four groups: UDMH intoxication acute response group and chronic response group, and corresponding control groups. UDMH was administrated through inhalation at the concentration of 8x10(-4)g/m(3) for 15 minutes. Animals of each group were sacrificed at 3, 6, 12, 24, 48 and 72 hours respectively after the intoxication. Pathologic changes and blood gas were examined. Chronic injuries and pathologic changes were also observed 1 year after the intoxication. RESULTS: Major pathological changes in the intoxication group were cerebral edema, degeneration and necrosis of neuron, enlargement and hemorrhage of capillary. Damages of different degree were found in liver, kidney, lung, heart, spleen, stomach, intestine, thymus, blood, bone marrow. Pallium ischemia was also found in the intoxicated rats 1 year after the intoxication, including ischemia damage of neuron in cerebral cortex, hemorrhage and focal liquefaction of thalamus and medulla conducting bind, dissociation, rupture, not uniform circuitry in conducting fibers. CONCLUSION: Our study reveals the basic pathological induced by intoxication of UDMH. The most severe stage of the injury appears 2-6 hours after intoxication. Long term investigation reveals pallium ischemia, thalamus hemorrhage and liquefaction in the medulla oblongata 1 year after the intoxication with UDMH. All the changes are significant.

Animals↗
PubMed2004

[Identification bcr-abl fusion gene in leukemia cells with oligonucleotide microarray].

To explore the application value of bcr-abl fusion gene deterction microarray in diagnosis, typing, choosing of treatment variant and prognosis judgment, probe for fusion gene detection was designed, oligonucleotide microarray was prepared; total RNA was extracted, reverse-transcripted and labeled by fluorescence, then cDNA was hybridized with microarray in order to detect bcr-abl fusion gene in leukemia cells. The results showed that better reaction conditions were gained by exploration of hybridizotion temperature and elution conditions, bcr-abl fusion gene in leukemia cells was detected by prepared miccroarray. In conclusion, oligonucleotide microarray is effective in detecting the fusion gene and has some unique advantages and certain clinical application value, but has some deficiency too. If microarray can be improved further, it could be used widely in the field of hematology.

Fusion Proteins, bcr-abl↗
PubMed2004

[Association of p53 gene polymorphism with susceptibility to ovarian cancer].

OBJECTIVE: To investigate the association of p53 codon 72 and p53 intron 3 (PIN3) polymorphism with susceptibility to epithelial ovarian cancer in northern Chinese women. METHODS: p53 codon 72 and PIN3 genotyping was performed by DNA fragments with sequence specific primers among 124 patients with ovarian cancer and 128 healthy control women. RESULTS: The frequency of the Pro and Arg allele among ovarian cancer patients and healthy controls were 53.2%, 46.8% and 46.1%, 53.9%. No significant difference in distribution of allelotype was shown between the two groups (chi(2) = 2.563, P = 0.109). The genotype frequencies of Pro/Pro, Pro/Arg, and Arg/Arg among ovarian cancer and healthy controls were 29.0%, 48.4%, 22.6% and 21.1%, 50.0%, 28.9% respectively. No significant difference was shown between the cases and controls (chi(2) = 2.598, P = 0.273). When the epithelial ovarian cancer patients were grouped according to the pathological characteristics, no significant difference was observed between the patients with serous cystadenocarcinoma or endometrioid carcinoma and the control group or between the two carcinoma groups for p53 codon 72 Pro/Arg (P > 0.05). When the epithelial ovarian cancer patients were divided into two subgroups according to the International Federation of Gynecology and Obstetrics (FIGO) standard, there was a significant difference between the early group (I approximately II) and the late group (III approximately IV) for Arg allelotype and Arg/Arg genotype (chi(2) = 7.494, P = 0.006 and chi(2) = 8.318, P = 0.004). The frequency of A, A'allelotype among ovarian cancer patients and healthy controls was 94.8%, 5.2% and 94.5%, 5.5%, no significant difference was shown between two groups (chi(2) = 0.013, P = 0.91). The genotype frequency of AA, AA', A'A' was not significantly different between the ovarian cancer and healthy controls (chi(2) = 0.301, P = 0.583). There was no significant difference in the frequencies of allelotypes and genotypes between patients with serous systadenocarcinoma and those with endometrioid carcinoma and between patients with ovarian cancers and the control subjects (all P > 0.05). The frequencies of allelotypes and genotypes were not significantly different between early and late ovarian cancers (chi(2) = 0.014, P = 0.906 and chi(2) = 0.137, P = 0.711). CONCLUSIONS: In northern Chinese women, p53 codon 72 Pro/Arg and p53 PIN3 gene polymorphisms are not associated with development of ovarian cancer. Arg/Arg genotype may be used as a stratification marker according to the standards of FIGO for ovarian cancer.

Adult↗
PubMed2004

[Tumor necrosis factor-alpha gene polymorphisms and risk of coronary heart disease].

Tumor necrosis factor-alpha(TNF-alpha) is a cytokine that has multiple functions. It could be involved in cardiovascular pathophysiology. Given this possibility, we measured serum TNF-alpha level by ELISA and use PCR-RFLP methods to examine the distribution of TNF-alpha locus gene polymorphism at -857 and -863 sites in coronary heart disease(CHD) patients and matched controls. We found the serum level of TNF-alpha of CHD is higher than that of controls(P<0.05),-863 genotype and allele have significant difference between two groups(P<0.05),and there are no difference in two groups at -857 site.

Aged↗
PubMed2004

[Study on thermo-sensitive intelligent targeting type drug carriers (II) microcapsules with grafted thermo-sensitive gates].

Environmental stimuli-responsive microcapsules are getting more and more interests because of their potential applications in site-specific and time- and rate-programmed controlled-release. In this study, thermo-responsive microcapsules with linear grafted poly(N-isopropylacrylamide) (PNIPAM) gates on the inner pore surface were prepared, and the thermo-responsive controlled-release experiments were carried out. Interfacial polymerization was introduced to prepare polyamide porous microcapsules, and plasma-graft pore-filling polymerization was used to graft PNIPAM into the pore of the microcapsule membranes. The experimental results showed that PNIPAM-grafted microcapsules were featured with thermo-responsiveness due to the thermoresponsive swollen-shrunken property of PNIPAM chains grafted on the inner pore surface of the microcapsule membrane. At temperatures below the lower critical solution temperature (LCST), the linear grafted PNIPAM chains on the inner pore surface were in the swollen state, and the pores in the membrane were closed and the solute molecules were restrained to pass, as a result the release rate was low. In contrast, the grafted PNIPAM chains were in the shrunken state at temperatures above the LCST, and therefore the pores in the membrane were open, and a high release rate was the result.

Acrylic Resins↗
PubMed2004

[Intelligent polymeric systems for glucose-responsive insulin delivery].

Polymeric drug delivery system for insulin controlled-release is one of the most active fields of research and development in the world. Up to date, several kinds of intelligent drug carriers for glucose-responsive insulin delivery have been reported. On the basis of a large quantity of references on this topic, a review has been made on the developments of the intelligent polymeric systems for glucose-responsive insulin delivery.

Delayed-Action Preparations↗
PubMed2004

[Evaluation of anti-HCV detection kits using recombinant antigens derived from various HCV regions].

OBJECTIVE: To evaluate the first and second assay kits currently used in blood centers for screening HCV infected blood, and to provide basis for a better match of the two assay kits. METHODS: Using the newly developed multi-recombinant-HCV-antigen supplementary assay kit, the authors evaluated concurrently the specificity and sensitivity of two domestic and one imported anti-HCV detection kits. RESULTS: Discrepancy in specificity and sensitivity existed among the two domestic HCV kits, and overall quality was slightly below that of leading or main stream imported HCV kit. CONCLUSION: The newly developed multi-recombinant-HCV-antigen supplementary assay kit is useful in the evaluation of HCV antibody detection kit currently in use. It provides qualified assessing kit to capture antibodies against various HCV antigens. The present paper provided guidance for selecting a better match of the two screening kits and improved screening efficiency.

Blood Donors↗
PubMed2004

[Synthesis and in vitro antitumor activity of multi-methoxyl carbazole analogues].

AIM: To design and synthesize new methoxyl carbazole analogues as antitumor compounds. METHODS: Methoxyl-nitrobiphenyls (3a-3c) were prepared through the Ullmann reaction of 4,5-dimethoxyl-2-bromonitrobenzene and methoxyl-iodobenzene compounds with the catalysis of copper powder, and then reduced by P(EtO)3 to obtain methoxyl carbazoles 4a-4c. The modification at 9-position of the methoxyl carbazoles (4a-4c) gives 16 carbazole derivatives (5a-5p). These compounds were confirmed by 1HNMR, MS, IR and elemental analysis. RESULT: In vitro antitumor activities evaluation in vitro demonstrated that IC50 value of the target compounds 4c, 5a, 5b, 5g, 5h, 5i, 5l, 5n and 5p against HT-29 cells were 12.1, 10.6, 8.1, 3.1, 4.4, 10.1 and 9.2 micromol x L(-1) respectively, and IC50 value of the target compound 4a against KB was 17.7 micromol x L(-1). CONCLUSION: Some of the target compounds have better inhibitory effects against H-29 and KB cells.

Antineoplastic Agents↗
PubMed2004

[Influence of chemotherapy on Th1/Th2 cytokine switching in stomach cancer patients].

OBJECTIVE: To observe the influence of chemotherapy on the switching of Th1/Th2 cytokines in stomach cancer patients. METHODS: Th1/Th2 cytokine genes expressed by peripheral blood mononuclear cells of stomach cancer patients before and after chemotherapy were detected by RT-PCR. RESULTS: The expression of Th2 cytokines was dominant in patients before chemotherapy, and the dominancy became less marked after chemotherapy. CONCLUSION: The immune deviation with Th2 predominance in stomach cancer patients has a tendency to become reversed after chemotherapy.

Adenocarcinoma↗
PubMed2004

[Flame temperature distribution measurement of solid propellants].

Many high temperature bodies such as flame, in which chemical reactions are very complex, emit their own spectra. These emission spectra usually consist of the spectral lines, spectral bands and the continuous spectra. In some cases, the spectral lines gather together. It is very difficult to find the right single spectral line when the spectral line intensity method is used. To deal with this problem, the idea that the single spectral line intensity is replaced by the total intensity of many spectral lines to measure the temperature is mentioned. And the relative intensity method is also changed to deal with this idea. The measurement of the temperature distribution based on this improved method is successful, and the measurement results are compared with the results of the thermocouple method.

English Abstract↗
PubMed2004

[Combustion temperature measurement of solid propellant by remote sensing FTIR].

The combustion temperature of solid propellant was measured in this paper. Emission spectra of the combustion flame were collected with remote sensing FTIR at the resolution of 4 cm(-1). The combustion temperatures with the burning time were calculated from the maximum spectral line intensity and the molecular rotation-vibration spectra of HF molecule, respectively. Combustion temperatures at each time were all 1 788.8 K from the maximum spectral line intensity method. For comparison, the temperatures calculated from the molecular rotation-vibration spectra were 1 859.7, 1 848. 3, 1 804.0 and 1 782.7 K, respectively. Results show that the two methods are all dependable in measuring combustion temperature of solid propellant. But the maximum spectral line intensity method is more convenient and rapid than the other when the combustion is relatively stable.

English Abstract↗
PubMed2004

[Enhanced ergosterol production by recombinant Saccharomyces cerevisiae 1190 harboring Vitreoscilla hemoglobin gene (vgb)].

Ergosterol is a principal sterol of fungi. It is a raw material for production of vitamin D2, hydrocortisone, progesterone and brassinolide. Synthesis of ergosterol requires molecular oxygen, and low oxygen tensions was reported to dramatically reduce ergosterol concentration. Vitreoscilla Hemoglobin Gene (vgb), a homodimeric hemoglobin gene from Gram-negative obligate aerobic bacterium Vitreoscilla, enables a higher specific cellular oxygen uptake rate, it also improves the oxygen transportation. In this study, recombinant plasmid pVgb-kanMX4 containing Vitreoscilla Hemoglobin Gene (vgb) and geneticin (G418) was constructed and transformed into Saccharomyces cerevisiae 1190 for enhanced ergosterol production. With sufficient oxygen supply, the ergosterol contents of recombinant and wild type strains grown in shake flasks were 1.07% and 0.573%, respectively. Under oxygen limitation condition, ergosterol contents in recombinant and wild type strains were reduced to 0.39% and 0.25%, respectively. In a 30 hours fermentation study conducted in a 5 liter fermentor, 15.1 g/L Cell Dry Weight (CDW) containing 1.38% ergosterol was obtained from growth of the recombinant strains; Only 14.8 g/L CDW containing 0.9% ergosterol was produced by the wild type strain. These results demonstrated that vgb played a role in enhancing ergosterol production.

Bacterial Proteins↗