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Biomedical subjects

Yan Li

Publications and source records attributed to Yan Li.

At least 649 records · Page 36Linked to original sources
PubMed2003

[Error analysis of temperature measurement by Boltzmann plot in atomic emission spectroscopy for a high-density plasma produced by electrothermal capillary discharge].

The present paper analysed in detail the reasons for the errors found in the literature when Boltzmann plot was used for the temperature measurement of a high-density plasma produced by electrothermal capillary discharge. The reliability of experiment can reach as high as 98%-99.5% and the error is only +/- 6.5% when the spectroscopic parameters, such as transition probability A, statistical weight of upper level g, and the energy of upper level Ei, are selected correctly for the temperature measurement of a high-density plasma produced by electrothermal capillary discharge by Boltzmann plot in atomic emission spectroscopy.

English Abstract↗
PubMed2003

[Combustion temperature measurement of solid propellant and the effect of organic compound on combustion temperature].

The FTIR emission spectra in the spectral range of 4,500-300 cm-1 for the solid propellants were measured by a remote sensing FTIR system. The P-branch of fine structure of HCl fundamental band lying at 3.46 microns was used for precise combustion temperature measurement of the solid propellant. The effect of the organic compound in the solid propellant on the combustion temperature was discussed.

English Abstract↗
PubMed2003

[Platelet phospholipase A2 mRNA content changes and cDNA cloning in rat blood with bacteria infection].

AIM: To explore the changes of rat platelet phospholipase A2 (PLA2) mRNA content in bacteria infected rat and study the cDNA and amino acid sequences of the PLA2 structure to lay a good foundation for the development of new antibiotics. METHODS: The PLA2 mRNA level in blood was determined by RT-PCR. The DNA sequence was cloned and analyzed. RESULTS: After injection of bacteria in rats, the mRNA level of PLA2 in blood increased markedly. The cDNA and amino acid sequence were highly homologous to other PLA2 cDNA from different tissues of the rat. CONCLUSION: Platelet PLA2 in blood responded quickly to bacteria infection in gene level. Therefore, the PLA2 protein was produced increasingly which was shown to control the infection with bacteria. Although there are little difference between PLA2 cDNA cloned from blood and other sources in DNA and amino acid sequences, the catalytic site for enzymatic activity and basic structure are identical.

Amino Acid Sequence↗
PubMed2003

[Real time diagnostics of instantaneous temperature of combustion and explosion process by modern spectroscopy].

The combustion temperature is one of the important parameters to express flame combustion and explosion characteristics. It will effectively guide the design and manufacture of new model explosives, industrial explosive materials, and weapons. The recent developments and applications of real time diagnostics of instantaneous temperature of combustion and explosion processes by modern spectroscopic methods, such as atomic absorption-emission method, atomic emission two-line spectroscopy, atomic emission multiline spectroscopy, molecular rotation-vibration spectroscopy, coherent anti-stokes Raman scattering (CARS) and plane laser-induced fluorescence (PLIF), were reviewed in this paper. The maximum time resolution of atomic absorption-emission method is 25 microseconds. The time resolution of atomic emission two-line spectroscopy can reach 0.1 microsecond. These two methods can completely suit the need of real time and instantaneous temperature diagnostics of violent explosion and flame combustion. Other methods will also provide new effective research methods for the processes and characteristics of combustion, flame and explosion.

English Abstract↗
PubMed2003

[Analysis of HLA matching probability in Guangzhou Cord Blood Bank].

The HLA matching results for 1 060 patients searching donors within 3 000 units of umbilical cord blood in Guangzhou Cord Blood Bank from 1998 to 2002 were analyzed. There were 119 (11.23%) and 992 (93.58%) patients found 6/6 and more than 4/6 of HLA matched loci of unrelated cord blood donors respectively. 61.29% of probability in all patients could find one or more cord blood with 4/6 or more matched loci and total nucleated cell (TNC) dose of >or= 3.7 x 10(7)/kg. The highest mean body weight in these supplied patients was 79 kg. The probability was 89.79% for those patients with TNC dose of >or= 2.0 x 10(7)/kg and >or= 4/6 of HLA loci matched. In these patients, the highest weight was 175 kg. In conclusion, a cord blood bank with 3 000 units or more of cord blood in stock shows a high probability of HLA matching and can meet the requirement of TNC >or= 3.7 x 10(7)/kg dose in child and part of adult patients. The umbilical cord blood is a good alternative stem cell source for all patients including adults.

Blood Banks↗
PubMed2003

[Measurement and analysis of different serum PSA in patients with benign prostatic hyperplasia].

OBJECTIVES: To analyze the stability of different serum prostate-specific antigens (PSA) in patients with benign prostatic hyperplasia (BPH), and investigate their application value in the diagnosis of prostate disease. METHODS: One hundred and five patients with BPH were divided into 3 groups by their total PSA (tPSA) level, 67 in group A (tPSA < 4 micrograms/L), 26 in group B (4 micrograms/L < or = tPSA < or = 10 micrograms/L) and 12 in group C (tPSA > 10 micrograms/L). These patients were also divided into another 3 groups by age, 18 in group a (< or = 55 years old), 33 in group b (from 56 to 69 years old) and 54 in group c (> or = 70 years old). tPSA, free PSA (fPSA) and complexed PSA (cPSA) were measured by magnetism-particulate-immuno-chemistry luminescence method, the ratios of cPSA/tPSA, fPSA/tPSA, fPSA/cPSA were calculated in 105 patients with BPH, and their stabilities were compared in different tPSA level and age groups. RESULTS: The ratios of cPSA/tPSA, fPSA/tPSA and fPSA/cPSA were steadier than other PSAs in different tPSA level and age groups with BPH. CONCLUSION: The ratios of cPSA/tPSA, fPSA/tPSA and fPSA/cPSA probably have more application value in the diagnosis of prostate disease.

Adult↗
PubMed2003

[Experimental study and numerical calculation on cross-sectional temperature fields of animal's tongue].

Bio-heat transfer in the tongue body is studied combining the mechanism of tongue inspection in Traditional Chinese Medicine. Parameters such as the temperature of lingual surface, the blood perfusion of the dog's tongue and so on are measured and the influences of the blood perfusion, the arterial blood temperature, the arterial cross-sectional areas and positions on the temperature distribution in the cross-sections are studied. Then the two-dimensional temperature fields in different cross-sections are numerically solved by the finite element method (FEM). The results show that the vascular cross-sectional areas vary with the elasticity change of the vessel walls resulting from the variation of the blood perfusion. And the temperature distribution in the cross-section mainly depends on the arterial cross-sectional areas and positions. The results can help to analyze the bio-heat transfer characteristic of the tongue. According to this method, the sectional temperature fields in whatever place of the tongue can be calculated under different blood perfusion and on the condition that the influence of the venous blood temperature on the temperature field of the tongue is considered. We can further probe into the relationship between the temperature fields of the lingual surface and that of cross-sections. This can provide the foundation for further investigation into the bio-heat transfer mechanism and the calculation on three-dimensional temperature fields of the tongue.

Animals↗
PubMed2003

[Diagnostic value of complexed prostate-specific antigen for prostate cancer].

OBJECTIVE: To assess the clinical value of serum complexed prostate-specific antigen(cPSA) in the diagnosis of prostate cancer (PCa). METHODS: Serum samples were obtained from 110 men with untreated benign prostatic hyperplasia (BPH) and 78 men with untreated PCa. The levels of cPSA, total PSA (tPSA) were determined by autoimmunochemistry luminescence method. RESULTS: Both cPSA and cPSA/tPSA ratio were significantly different between patients with PCa and BPH (P < 0.005), especially, in men with tPSA values between 4.0-10.0 micrograms/L (the diagnostic gray zone). When cPSA/tPSA > or = 0.78 was taken as the cut-off value conjugated with tPSA < or = 10.0 micrograms/L, the sensitivity, specificity, negative predictive value and positive predictive value were as high as 97.8%, 95.8%, 81.9% and 96.5%. CONCLUSIONS: With the introduction of cPSA and cPSA/tPSA ratio, early diagnosis of PCa by the assessment of tPSA has been made more sensitive and reliable, especially when the tPSA is within the diagnostic gray zone.

Aged↗
PubMed2003

[The use of Juniper's asthma quality of life questionnaire in Chinese asthmatics].

OBJECTIVE: One of the most important objectives in the management of asthma is to improve the quality of life of patients. We summarized our experience in using Juniper's asthma quality of life questionnaire (AQLQ) in Chinese asthmatics. METHODS: Measurement instruments included self-administered AQLQ mandarin Chinese version and its standardized version. The data were from 210 AQLQ evaluations from 96 patients. RESULTS: AQLQ and its four domains weakly correlated with forced expiratory volume in 1 second (FEV(1)) except the environment domain (r: 0.201 - 0.284). If the asthmatic patients were graded into 4 groups based on FEV(1), AQLQ and its four domains significantly detected the differences among the groups. The change of AQLQ, however, was not correlated with the change of FEV(1). The change of AQLQ domain of symptoms was correlated with the change of peak expiratory flow. CONCLUSION: The Juniper's AQLQ performs well in Chinese asthmatics. AQLQ is correlated with pulmonary function and probably more sensitive and accurate than pulmonary function in the evaluation of disease severity.

Adult↗
PubMed2003

[Relationship of interleukin-1B and interleukin-1 receptor antagonist gene polymorphisms with chronic hepatitis B].

OBJECTIVE: To investigate the polymorphisms of interleukin-1B (IL-1B) promoter region -511C/T and interleukin-1 receptor antagonist (RN) gene, the relationship between the genotype of IL-1B and IL-1RN, and the susceptibility to chronic hepatitis B in Chinese population. METHODS: Genomic DNA was extracted from the peripheral blood of 190 patients with chronic hepatitis B and 249 normal controls and then was subjected to PCR amplification. The PCR product was digested by restriction endonuclease Ava I. The product of digestion was subjected to 2% gel-electrophoresis and ethidium bromide staining. RESULTS: The IL-1B -511C allele was detected in 0.50 of normal controls and 0.48 of patients, while the IL-1B -511T allele was detected in 0.50 of normal controls and 0.52 of patients. The frequency of CC genotype was 0.26 (65/249) and in normal controls 0.24 (45/190) in patients. The frequency of CT genotype was 0.47 (118/249) in normal controls and 0.49 (94/190) in patients. The frequency of TT genotype was 0.27 (66/249) in normal controls and 0.27 (51/190) in patients. The HBV-DNA copies in chronic hepatitis B with CC genotype were significantly decreased, compared with controls (P<0.05). Only four (1/1, 1/2, 2/2 and 1/4) of the five kinds of polymorphism of IL-1RN were found in this study. The frequencies of 1/1, 1/2, 2/2 and 1/4 were 0.88, 0.09, 0.01 and 0.02 in chronic hepatitis B patients respectively, while in controls were 0.81, 0.16, 0.01 and 0.02. The IL-1 RN*1 allele was detected in 0.94 of chronic hepatitis B patients and in 0.90 of controls, while the IL-1RN*2 allele was detected in 0.05 of patients and in 0.09 of normal controls. The frequencies of 1/2 genotype and IL-1RN*2 allele were lower in chronic hepatitis B than in controls (P<0.05). CONCLUSION: The polymorphisms of the promoter region -511C/T of IL-1B gene and IL-1RN intron 2 gene are associated with the development of chronic hepatitis B. The people with IL-1RN*2 allele may be protected against HBV infection, and the IL-1B -511 CC genotype may be linked to HBV-DNA copy.

Adolescent↗
PubMed2003

[The NAD(P)H: quinone oxidoreductase 1 C609T polymorphism and susceptibility to esophageal cancer].

OBJECTIVE: To investigate the association of the NAD(P)H: quinone oxidoreductase 1 (NQO1) C609T polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC) in a northern Chinese population. METHODS: The NQO1 C609T genotypes were determined by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) analysis in 193 patients with ESCC and 141 unrelated healthy controls. RESULTS: The frequency of the T allele (null) among ESCC patients was significantly higher than that among healthy controls (Chi-square=4.86, P=0.028). The NQO1 C/C and C/T genotype distribution among ESCC patients was not significantly different from that among healthy controls (Chi-square= 2.27 and 0.127; P=0.132 and 0.721, respectively). However, the T/T genotype frequency among ESCC patients was significantly higher than that among healthy controls (Chi-square=4.39, P=0.036). The NQO1 T/T genotype significantly increased the risk for developing ESCC, compared to the combination of C/C and C/T genotypes, with the adjusted odds ratio (OR) of 1.81 (95%CI: 1.04-3.15). This increased susceptibility exhibited pronouncedly in patients with family history of upper gastrointestinal cancers (adjusted OR=2.22, 95%CI 1.18-4.17). CONCLUSION: Determination of the NQO1 C609T genotype may be used as a stratification marker to predicate high-risk individuals for ESCC.

Esophageal Neoplasms↗
PubMed2003

[Refolding and purification of Plasmodium falciparum glutamate dehydrogenase fusion protein].

OBJECTIVE: To establish the method for renaturation and purification of the fusion protein of Plasmodium falfiparum (FCC1/HN ) glutamate dehydrogenase (GDH) with glutathione S-transferase (GST). METHODS: The recombinant plasmid GDH/pGEX-4T-1, encoding the full-length GDH gene, was transformed into E.coli BL21 (DE3) to achieve IPTG-induced high expression of GDH/GST in the form of inclusion bodies identified by SDS-PAGE. After denaturation with 8 mol/L urea, the inclusion bodies were subjected to 3 different renaturation methods, namely Sephacryl S-200 chromatography, dialysis and dilution, for refolding of the fusion protein. The refolded GDH/GST was then purified by different chromatographic approaches. RESULTS: SDS-PAGE analysis showed that the expression GDH/GST fusion protein mounted up to approximately 25% of the total bacterial protein. The dilution was better than the other two methods for the refolding of the fusion protein, with the optimized renaturation condition necessitating the presence of 20 mmol/L Tris-HCl and 1 mmol/L EDTA at pH8.5 with GSSG/GSH ratio of 1 10, which resulted in a recovery rate exceeding 90%. Two-step ion exchange chromotography was optimal for purification of the fusion protein. CONCLUSION: The high-purity and biologically active GDH/GST can be acquired by dilution renaturation followed by two-step ion exchange chromatography.

Animals↗
PubMed2003

Expression of killer cell inhibitor receptors on immunocompetent cells with relation to graft-versus-host disease after hematopoietic stem cell transplantation.

The study was aimed at the exploration of relationship between T cells expressing killer cell inhibitor receptors (KIR, CD158 and CD94) and graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation. The expression rates of CD158a, CD158b and CD94 on T cells and NK cell were detected by flow cytometry and donor/recipient HLA-Cw was analyzed using PCR after peripheral blood stem cell transplantation (PBSCT) and umbilical cord blood transplantation (UCBT). After both PBSCT and UCBT, the rates of CD3(+)CD158a(+) and CD3(+)CD158b(+) T cells increased, especially the rate of CD8(+)CD158b(+) T cells. In both acute and chronic GVHD groups, the rate of CD3(+)CD158b(+) T cells increased, especially in acute GVHD. The CD94 mainly expressed on CD3(+)CD8(+) T cells. The percentage of the expression of CD94 on CD4(+) and CD8(+) cells after UCBT and PBSCT increased significantly. The expression of KIR in GVHD (early stage of transplantation) increased but the expression of KIR in chronic GVHD (advanced stage of transplantation) decreased. Five patients who HLA-Cw matched had no severe GVHD. In four patients who underwent allo-PBSCT and UCBT from related HLA-matched donors, only 2 patients had no aGVHD. Four patients underwent transplantation from unrelated HLA-matched donors had GVHD. These observations suggested that there is some relationship between GVHD and KIR expression on T cells. CD158b might be an inhibitory molecule of T cell activated at early stage after transplantation. Understanding the mechanism of GVHD with the expression of KIR on T cells, especially those binding the HLA-Cw might shed light on the establishment of the specific immunotolerance for the prevention of GVHD. To pay attention to HLA-Cw typing is very important to reduce GVHD and increase GVL effect in related or unrelated HLA-matched transplantation.

Antigens, CD↗
PubMed2003

[Photorefractive keratectomy for correction of anisometropia after cataract surgery].

OBJECTIVE: To determine the visual and refractive outcome of photorefractive keratectomy (PRK) in patients with anisometropia after cataract surgery. METHODS: We studied a series of 31 eyes of 24 patients who underwent PRK for the correction of anisometropia after cataract surgery. Pre- and post-operative vision, refraction, anisometropia and surgical complications were observed. These patients were followed-up at 12.2 months after laser ablation. RESULTS: One week following PRK, the uncorrected visual acuity (UCVA) and the best correct visual acuity (BCVA) were improved significantly (P < 0.01). Mean spherical equivalent refraction (MSER) was decreased significantly to (1.12 +/- 0.55) D after PRK. The MSER was (1.27 +/- 0.56) D in myopia eyes and (0.81 +/- 0.38) D in hyperopia eyes one week after PRK, the difference between these two groups was statistically significant (P < 0.01). Astigmatism was decreased significantly after PRK (P < 0.01), the mean astigmatism was (0.49 +/- 0.38) D one week after the operation. Anisometropia was decreased from (3.44 +/- 1.07) D to (0.58 +/- 0.31) D after PRK, the difference between the pre-operative and post-operative anisometropia was statistically significant (P < 0.01). No serious complications occurred during or after the operation. CONCLUSION: PRK is a safe, reliable and effective method for correction of anisometropia after cataract surgery.

Adult↗
PubMed2003

[Expression of PTEN protein in oromaxillofacial tumor cell lines].

AIM: To investigate expression of PTEN protein in oromaxillofacial tumor cell lines and to compare the difference of PTEN protein expression between highly metastatic cancer cell lines and their parent cell lines. METHODS: ABC immunohistochemical staining was applied for detecting expression of PTEN protein in 8 kinds of cancer cell lines, including tongue cancer cell lines Tca8113 and HSC-3,oral bottom cancer cell line HSC-2, buccal cancer cell line BcaCD885, mucoepidermoid carcinoma cell line MEC-1, adenoid cystic carcinoma cell line SACC83, highly metastatic tongue cancer cell line Tb-TLP and highly metastatic mucoepidermoid carcinoma cell line M3SP2. RESULTS: Of the 8 kinds of cancer cell lines, 5 kinds of cancer cell lines were positive for PTEN protein expression. PTEN protein was located in cytoplasm around nucleus. 3 kinds of cancer cell lines, BcaCD885, Tb-TLP and M3SP2, lacked expression of PTEN protein. CONCLUSION: Deficiency of PTEN protein expression may play a certain role in cancer cell metastasis.

Animals↗
PubMed2003

Comparison of IL-6-induced STAT1 activation in different responsive cells.

AIM: To investigate the activation status of signal transducer and activator of transcription 1 (STAT1) induced by interlerkin-6 (IL-6) in different responsive cells. METHODS: Immunoblot analysis was performed with antibodies against STAT1 and tyrosine-phosphorylated STAT1. RESULTS: It's found that IL-6 had growth-promoting effects on 7TD1 and TF1 cells but had little effect on the tyrosine-phosphorylation of STAT1. On the other hand, IL-6 activated STAT1 in a dose and time-dependent manner in M1, R2 and U937 cells which underwent growth arrest and macrophage differentiation upon IL-6 induction. CONCLUSION: These results suggest that IL-6-induced STAT1 activation might be associated with growth-inhibitory effects, and our data might help to explain why IL-6 exerts distinct biological effects in different target cells.

DNA-Binding Proteins↗