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Biomedical subjects

Yan Zhang

Publications and source records attributed to Yan Zhang.

At least 145 records · Page 8Linked to original sources
PubMed2006

Gene expression of ornithine decarboxylase in lung cancers and its clinical significance.

Lung cancer is one of the most lethal cancers in China because of its high incidence and high mortality. Ornithine decarboxylase (ODC), an important enzyme in polyamine biosynthesis, is increased in cancer cells. Some chemotherapeutic agents aimed at reducing ODC expression show inhibitory effects on cancer cell growth, so ODC can be useful in gene diagnosis and gene therapy of cancers. In this study, we examined the effect of antisense ODC on lung cancer cells. A-549 cells were infected with rAd-ODC/Ex3as, a recombinant adenovirus containing the cytomegalovirus promoter, green fluorescent protein gene and 120 bp antisense ODC. The cell cycle was evaluated by flow cytometry. A nude mouse xenograft model was used in the tumorigenicity test. Reverse transcription-polymerase chain reaction, Western blot and immunohistochemistry were used to study the expressions of ODC on lung cancers. It was found that the growth of cells infected with rAd-ODC/Ex3as was substantially inhibited and cells were arrested at G1 phase. Cells infected with rAd-ODC/Ex3as can suppress tumor formation in a nude mouse xenograft model. The expression of ODC mRNA and ODC protein levels in lung cancer tissues was significantly higher than that in normal tissues (P<0.05), which correlated significantly with the stage of lung cancer (P<0.05). This study suggested that rAd-ODC/Ex3as has antitumor activity in human lung cancer cells. The ODC gene might play an important role in lung cancer and the overexpression of ODC might be related to the occurrence and development of lung cancer.

Animals↗
PubMed2006

Molecular profiling of the Clostridium leptum subgroup in human fecal microflora by PCR-denaturing gradient gel electrophoresis and clone library analysis.

A group-specific PCR-based denaturing gradient gel electrophoresis (DGGE) method was developed and combined with group-specific clone library analysis to investigate the diversity of the Clostridium leptum subgroup in human feces. PCR products (length, 239 bp) were amplified using C. leptum cluster-specific primers and were well separated by DGGE. The DGGE patterns of fecal amplicons from 11 human individuals revealed host-specific profiles; the patterns for fecal samples collected from a child for 3 years demonstrated the structural succession of the population in the first 2 years and its stability in the third year. A clone library was constructed with 100 clones consisting of 1,143-bp inserts of 16S rRNA gene fragments that were amplified from one adult fecal DNA with one forward universal bacterial primer and one reverse group-specific primer. Eighty-six of the clones produced the 239-bp C. leptum cluster-specific amplicons, and the remaining 14 clones did not produce these amplicons but still phylogenetically belong to the subgroup. Sixty-four percent of the clones were related to Faecalibacterium prausnitzii (similarity, 97 to 99%), 6% were related to Subdoligranulum variabile (similarity, approximately 99%), 2% were related to butyrate-producing bacterium A2-207 (similarity, 99%), and 28% were not identified at the species level. The identities of most bands in the DGGE profiles for the same adult were determined by comigration analysis with the 86 clones that harbored the 239-bp group-specific fragments. Our results suggest that DGGE combined with clone library analysis is an effective technique for monitoring and analyzing the composition of this important population in the human gut flora.

Adult↗
PubMed2006

Human CD4+ CD25hi Foxp3+ regulatory T cells are derived by rapid turnover of memory populations in vivo.

While memory T cells are maintained by continuous turnover, it is not clear how human regulatory CD4+ CD45RO+ CD25hi Foxp3+ T lymphocyte populations persist throughout life. We therefore used deuterium labeling of cycling cells in vivo to determine whether these cells could be replenished by proliferation. We found that CD4+ CD45RO+ Foxp3+ CD25hi T lymphocytes were highly proliferative, with a doubling time of 8 days, compared with memory CD4+ CD45RO+ Foxp3- CD25- (24 days) or naive CD4+ CD45RA+ Foxp3- CD25- populations (199 days). However, the regulatory population was susceptible to apoptosis and had critically short telomeres and low telomerase activity. It was therefore unlikely to be self regenerating. These data are consistent with continuous production from another population source. We found extremely close TCR clonal homology between regulatory and memory CD4+ T cells. Furthermore, antigen-related expansions within certain TCR Vbeta families were associated with parallel numerical increases of CD4+ CD45RO+ CD25hi Foxp3+ Tregs with the same Vbeta usage. It is therefore unlikely that all human CD4+ CD25+ Foxp3+ Tregs are generated as a separate functional lineage in the thymus. Instead, our data suggest that a proportion of this regulatory population is generated from rapidly dividing, highly differentiated memory CD4+ T cells; this has considerable implications for the therapeutic manipulation of these cells in vivo.

Adult↗
PubMed2006

A testing scheme for the detection of Mycobacterium avium subsp. paratuberculosis in bovine feces utilizing the ESP para-JEM liquid culture system.

A testing scheme for the detection of Mycobacterium avium subsp. paratuberculosis (MAP) in broth cultures of bovine fecal samples carried out in ESP para-JEM System was evaluated. The scheme included acid-fast staining (on signal-positive and signal-negative samples), and confirmation by PCR for 2 MAP-specific targets and subculture of all acid-fast positive PCR-negative samples. Two hundred and fifty bovine fecal samples were evaluated for the presence of MAP using this scheme. Thirty-seven (15%) of 250 fecal samples had a positive culture result when the proposed testing scheme was used, compared to 14 (6%) positive results when using the standard ESP para-JEM protocol (requiring samples to have a positive signal from the system, a positive acid-fast stain, and a positive IS900 PCR result), and 20 (8%) positives when conventional culture was performed on Herrold egg yolk (HEY) media. A preliminary comparison of real-time and conventional PCR on DNA extracted from 15 MAP-positive broth cultures by 3 different protocols suggested that conventional PCR may be a better choice for the confirmation of the presence of MAP in the liquid cultures than real-time PCR.

Animals↗
PubMed2006

Effects of Fructus Ligustri Lucidi extract on bone turnover and calcium balance in ovariectomized rats.

The aim of this study was to evaluate the effect of Fructus Ligustri Lucidi (FLL), a kidney-tonifying Chinese herbal medicine, on the biochemical markers of bone turnover, calcium metabolism and balance in osteoporotic rat model developed by ovariectomy. Four weeks after surgical operation, animals were randomly assigned to one of the four treatments for 14 weeks: sham-operated control treated with vehicle (sham, n=8), ovariectomized group treated with vehicle (OVX, n=8), OVX group treated with 17beta-estradiol (E(2), n=10, 2 microg/kg/d) and OVX group treated with FLL extracts (FLL, n=10, 550 mg/kg/d). Serum osteocalcin and urinary deoxypyridinoline levels were upregulated in rats in response to OVX, suggesting that the bone turnover rate was accelerated in these animals. Treatment of OVX rats with FLL extract could prevent OVX-induced increase in bone turnover by suppression of both serum osteocalcin (p<0.05, vs. OVX) and urinary deoxypyridinoline (p<0.05, vs. OVX) levels. In addition, FLL extract could prevent OVX-induced loss of calcium in rats by increasing the intestinal calcium absorption rate (p<0.01, vs. OVX), suppressing urinary Ca excretion (p<0.05, vs. OVX) as well as increasing bone calcium content (p<0.05, vs. OVX). Our study is the first to report that FLL can modulate bone turnover and calcium balance in OVX rats and it might be a potential candidate for prevention and treatment of postmenopausal osteoporosis.

Animals↗
PubMed2006

Contribution of cooperativity and the Bohr effect to efficient oxygen transport by hemoglobins from five mammalian species.

By using published experimental values of the standard oxygen (O2) equilibrium curve and the in vivo arterial and venous O2 pressure (PO2) of fetal and maternal blood in five mammalian species (human, cow, pig, sheep, and horse), we investigated the relationship between the efficiency of O2 delivery and the effectiveness of the Bohr shift, and discussed the significance of cooperativity for mammalian Hb. The O2 delivery of fetal blood was more efficient than that of maternal blood, and the effectiveness of the Bohr shift at both O2 loading and release sites of fetal blood was high. A linear relationship was observed between the efficiency of O2 delivery and the effectiveness of the Bohr shift at O2 loading sites of the five mammalian species. In both fetal and maternal blood, the theoretically obtained optimal P50 value for O2 delivery (optP50(OD)) was nearly equal to the optimal P50 value for the effectiveness of the Bohr shift at the O2 loading site (optP50(BS)(loading)). This phenomenon was favorable for fetal blood to uptake O2 from maternal blood with the aid of the Bohr shift and to deliver a large amount of O2 to the tissues. The optP50s for the effectiveness of the Bohr shift at given arterial PO2 (PaO2) and venous PO2 (PvO2) were derived as follows: optP50(BS)(loading) = PaO2((n+1)/(n-1))(1/n), and optP50(BS)(release) = PvO2((n+1)/(n-1))(1/n). The relationship between in vivo PO2s and n, PaO2/PvO2 = ((n+1)/(n-1))(2/n), was derived by letting optP50 for the efficiency of O2 delivery be equal to that for the effectiveness of the Bohr shift.

Animals↗
PubMed2006

[Application of multi-slice spiral CT in the diagnosis of pulmonary hypertension].

OBJECTIVE: To evaluate the utility of multi-slice spiral CT in the diagnosis of pulmonary hypertension. METHODS: The clinical and multi-slice spiral CT data of 22 patients with pulmonary hypertension were retrospectively analyzed. The diagnoses included chronic thromboembolic pulmonary hypertension (CTEPH) (n = 9), primary pulmonary hypertension (PPH) (n = 7), connective tissue diseases (n = 2), portal-pulmonary hypertension (n = 2), eosinophilia-myalgia syndrome (n = 1), and fibrosing mediastinitis (n = 1). Lung parenchyma, such as ground-glass opacity, mosaic attenuation and septal thickness, mediastinum, pulmonary vascular, right ventricular enlargement and interventricular septum displacement were evaluated on CT. RESULTS: CT pulmonary angiography (CTPA) accurately diagnosed 95% of pulmonary hypertension and the signs of right ventricular dysfunction. Pulmonary embolism was found in 9 patients. The incidence of mosaic attenuation was significantly higher in CTECH than in PPH (P = 0.034). CONCLUSION: CTPA can accurately diagnose pulmonary hypertension and thereby provide useful information for the etiological diagnosis.

Adult↗
PubMed2006

[Application of 16-slice spiral CT in lower extremity arterial occlusive diseases].

OBJECTIVE: To determine the diagnostic accuracy of 16-slice spiral CT in assessing the lower extremity arterial occlusive diseases. METHODS: Thirty patients with suspected peripheral arterial occlusive diseases underwent 16-slice spiral CT angiography (CTA) of lower extremity arteries. All these patients also underwent digital subtraction angiography (DSA) two weeks before or after CTA. CT angiograms were produced using maximal intensity projection, volume rendering technique, and curved planar reconstruction. Using DSA as the standard reference, the diagnostic accuracy of CTA was determined. RESULTS: When detecting segments with > or = 50% stenosis, the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of CTA were 94.3% (115/122), 98.4% (548/557), 97.6% (663/679), 92.7% (115/124), and 98.7% (548/555), respectively. CONCLUSION: 16-slice spiral CT has high sensitivity, specificity, and accuracy in detecting lower extremity arterial occlusive diseases and may partially substitute DSA examinations.

Aged↗
PubMed2006

[Effects of sensitized donor lymphocyte infusion on the chimerism and graft-versus-host disease after nonmyeloablative allogeneic stem cell transplantation].

To explore whether the complete donor chimerism could be achieved and graft-versus-host disease could be alleviated by donor lymphocyte infusion which was sensitized by the skin of the recipient, female C57BL/6 mice (H-2(b), B6) as recipients received total body irradiation (TBI) of 5.5 Gy ((60)Co gamma-ray) on day 0 followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). The allo-grafts consisted of 2 x 10(7) peripheral hematopoietic stem cells from mobilized male BALB/c (H-2(d)) donor mice with the granulocyte colony-stimulating factor (G-CSF). Day 2 after allo-HSCT, the recipient mice were given 200 mg/kg cyclophosphamide intraperitoneally. Afterwards these recipient mice were infused 2 x 10(6) sensitized or unsensitized-donor lymphocytes at the 28 days after transplantation. The results showed that the mice receiving sensitized-donor lymphocyte infusion did not suffer from GVHD and the phenotypic character of the recipient mice (black color) converted to that of the donor mice (white color), and to become full-donor chimerism. It was found that the ratio of CD4(+)/CD8(+) T lymphocytes of them decreased at the earlier period and increased after half month, but which were also lower than that of the normal value. While various grades of acute GVHD was observed in that of the control group and the mixed-chimeras were maintained, though it increased a little, and the ratio of CD4(+)/CD8(+) T lymphocytes increased at first, then decreased to the normal level half month later. It is concluded that sensitized DLI converted mixed to complete donor chimerism without GVHD, and the rate of CD4(+)/CD8(+) has close relation to the incidence of GVHD.

Animals↗
PubMed2006

[Reference values of blood lymphocyte immunophenotype in the normal healthy adults of Ugyur and Han nationalities in Xinjiang].

This study was aimed to establish the reference values of blood lymphocyte immunophenotype in healthy adult between Ugyur and Han nationalities in Xinjiang and to compare the difference between these two nationalities in respect to nationality and gender, anticoagulated peripheral blood samples of 75 Ugyur people and 104 Han people were stained with monoclonal antibodies; the lymphocytes were analyzed by flow cytometry for the expression of lymphocyte-population bearing surface markers, the data were analyzed by SPSS 11.0. The results showed that the reference ranges of blood lymphocyte subsets in Uygur and Han adults were as follows: total T cells amounted to 67.85 +/- 8.97% and 69.98 +/- 10.14% respectively; helper T cell to 36.86 +/- 5.74% and 40.07 +/- 6.10% respectively; inhibitor T cell to 26.67 +/- 6.15% and 27.16 +/- 6.29% respectively; CD4/CD8 ratio to 1.46 +/- 0.47 and 1.56 +/- 0.47 respectively; NK cell to 16.91 +/- 9.89% and 12.81 +/- 7.34% respectively; B cell to 10.09 +/- 3.33% and 11.78 +/- 3.81% respectively; CD3(+)/HLA-DR(+) to 10.05 +/- 2.95% and 11.27 +/- 4.98% respectively; CD25(+) cell to 1.76 +/- 5.26% and 4.10 +/- 4.30% respectively. The differences of those two nationalities were mainly in total T cells, NK cell, B cell and CD25(+) cell. Furthermore there were also some differences between male and female. There might exist differences in helper T cells, CD4/CD8 ratio between Ugyur male and female, while this difference in Han lied in inhibitor cell and NK cell. Compared to those of two nationalities, the helper T cell percentage and CD4/CD8 ratio of Uygur male were lower than those in Han male. And in female, Uygur people had higher percent of NK cell (P < 0.01), but lower CD25(+) cell than those in Han's (P < 0.01). In conclusion, the nationalities and gender could influence the reference value of lymphocyte immunophenotype, the reference values of blood lymphocyte immunophenotype in the normal healthy adults of Ugyur and Han nationalities in Xinjiang were defined, and the differences between these two nationalities in respect to nationality and gender were elucidated.

Adult↗
PubMed2006

[Chemical stabilization technology in treating with flyash using apatite].

Toxicity leaching characteristics and chemical compositions of sample flyash collected from municipal solid waste incinerator was analyzed, it was clear that different heavy metals were contained in flyash and the heavy metal leaching concentration for Pb, Zn, Cd was 11.8, 164.9 and 31.2 mg/L respectively which was much higher than that in Hazardous Waste Toxicity Leaching Standards. A new kind of inorganic chemical agent apatite was chosen to treat with this kind of incineration flyash, the results indicate that the heavy metals (not including Cd in some samples) in the treated flyash using apatite at dosage 7% can reach the landfilling standards for hazardous waste, and the treated flyash can have better stabilization when the size of apatite was 74 microm, and the heavy metal leaching concentration of the treated flyash keep stable at a curing time of 1 day, and it can keep stabilization with a broader pH value of 3 to 11. Thus the risk of secondary pollution for the treated flyash was reduced dramatically when the environment conditions change.

Apatites↗
PubMed2006

[Sequencing the Rhesus boxes and determining the homozygosity of RHD gene in Han Chinese with RhD negative].

OBJECTIVE: To analyze the sequences of Rhesus boxes of RhD gene, and explore the genetic mechanism of RhD negative phenotype in Chinese Han population. Meanwhile the PCR product of Rhesus boxes is analyzed for determining RHD gene homozygosity. METHODS: DNA of 74 RhD negative samples were firstly analyzed with multiplex PCR-sequence specific primer(SSP). The further analysis was given to Rhesus boxes specific sequencing and RHD gene homozygosity determined by PCR-restriction fragment length polymorphism(RFLP) analysis to Rhesus boxes. RESULTS: In DNA samples of 74 RhD negative individuals, 46 samples(62%) showed the absence and homozygous negative of RHD gene; 22 samples(30%) all showed the existence of RHD specific exons, of which 19 were RHD gene heterozygous and 3 were homozygous; regardless of PCR-RFLP analysis showing no RHD specific exons, but further analysis of RHD specific PCR revealed one RHD gene, at least RHD gene exon 1 and 10 existing in 5 DNA samples(7%); 1 sample(1%) was lacking RHD exon 6 although the multiplex PCR showed the RHD gene to be positive. Analyzing the hybrid Rhesus box of 27 RhD negative samples revealed the Han Chinese population to have the same DNA sequence of hybrid Rhesus box as Caucasians. CONCLUSION: The RHD gene deletion is the main molecular mechanism of causing RhD negative formed in Han Chinese population, who have had the RHD gene deletion taken place within the defined breakpoint region as Caucasians.

Asian People↗
PubMed2006

[Development of a new hydrophobic interaction chromatography absorbent and its application to the purification of recombinant hepatitis B surface antigen].

A new hydrophobic absorbent based on homemade highly cross-linked agarose beads was synthesized by immobilizing butyl derivative onto the matrix linkage. The density of ligand was controlled by adjusting the concentration of butanethiol and the synthesis route was optimized by evaluating the purification efficiency of recombinant Hepatitis B surface antigen (HBsAg) expressed by Chinese hamster ovary (CHO) cell line. A high performance absorbent was finally screened out with up to 80% of HBsAg recovery and purification-fold (PF) about 20. Furthermore, the column pressure was about 0.06 MPa under the flow rate of 500cm/h, and no leaked butyl were detected after exposing the gel in common buffers, chaotropic agents, high concentrations of denaturing agents such as guanidine hydrochloride, urea and polar organic solvents. These results demonstrated that the absorbent have high physico-chemical stability, so it was available for the downstream process. Finally, after scaled up to 2L wet gel/batch, the absorbent was applied to the integration of three-step chromatography and obtained the purified CHO-HBsAg with 95% purity by SDS-PAGE and HPLC, which meet the requirements of SFDA. The purification efficiency and the reproducible ability of the absorbents were also evaluated from batch-to-batch. The results demonstrated that the absorbent met the requirement of scalable, reproducible, economic effect as well. This absorbent is a promising alternative exported HIC gel for wildly being used in Chinese pharmaceutical industries.

Animals↗
PubMed2006

[Effects of enhanced external counterpulsation in atherosclerosis and NF-kappaB expression: a pig model with hypercholesterolemia].

OBJECTIVE: To study the effects of enhanced external counterpulsation (EECP) on the vascular morphology, and endothelial function using experimentally induced hypercholesterolemic pigs. METHODS: Thirty five male pigs were randomly divided into three groups: 7 normal control animals, 11 hypercholesterolemic animals, and 17 hypercholesterolemic animals receiving EECP. Serum cholesterol was measured. The coronary arteries and aortas were sampled for histopathologic and ultrastructural examination. The NF-kappaB protein expression of porcine coronary arteries was investigated by immunofluorescence. RESULTS: Compared with the normal controls, serum cholesterol levels were significantly higher in the hypercholesterolemic animals with or without EECP. The plaque/intimal area ratio of the aorta decreased significantly in animals receiving EECP [(3.33 +/- 2.40)%, versus (12.03 +/- 7.12)% in those without EECP, P < 0.05]. Lipid deposition, endothelial damage and proliferation of smooth muscle cells were less severe in animals receiving EECP than those not. Moreover, activation and expression of NF-kappaB also decreased significantly (P < 0.05) in animals receiving EECP. CONCLUSIONS: EECP improves the morphology and function of vascular endothelium, and retards the development and progression of atherosclerosis, likely through the inhibition of NF-kappaB signaling pathway.

Animals↗
PubMed2006

[Establishment of a pig model of chronic ally enhanced external counterpulsation].

OBJECTIVE: To establish a pig model of chronic external counterpulsation. METHODS: Twelve pigs were anaesthetized with sodium pentobarbital (< or =30 mg/kg.b.w.) and 846 mixture (< or =0.1 ml/kg.b.w.) and counterpulsed in a lateral position for 2 h every two days (totally 36 h) with 0.025 to 0.04 MPa/cm(2) pressure. RESULTS: External counterpulsation was successfully completed in all the animals. Combined administration of sodium pentobarbital and 846 mixture resulted in good anesthetic effect with reduced anesthetic dosage and minimal side effect on the viscera (the liver, kidney and heart, etc). CONCLUSION: The pig model of chronic external counterpulsation has been successfully established. Combined use of sodium pentobarbital and 846 mixture is recommended for chronic external counterpulsation.

Anesthesia, General↗
PubMed2006

[Impact of gender and age on in-hospital mortality after coronary artery bypass graft].

OBJECTIVE: The purpose of this study was to explore the association of gender and age on in-hospital mortality after coronary artery bypass graft (CABG) among the Chinese population. METHODS: A total of 2682 patients (male: 2316, female: 366) who underwent CABG surgery were retrospectively investigated between January 1st, 1997 and December 31st, 2001 for perioperative risk factors and in-hospital mortality rate after CABG. RESULTS: Preoperative comorbidity rate and postoperative complication rate were higher in women than that in men, although left ventricular ejection fraction was higher and the number of diseased vessels fewer in women than in men. The in-hospital mortality rate was three times higher in women than that in men (3.01% vs. 1.12%, P = 0.001), especially in the younger age group (2.6% vs. 0.5%, P = 0.001, risk-adjusted odds ratio 4.844, 95% CI: 1.549 - 15.142). In older patients, there was no notable difference in in-hospital mortality between the genders (3.7% for women vs. 2.4% for men, P = 0.383). CONCLUSIONS: Chinese woman, especially in younger age, had a higher in-hospital mortality rate post CABG than that in men, suggesting that younger female gender is an independent risk factor for in-hospital mortality after CABG. Future studies are warranted to clarify the underlying mechanisms.

Age Factors↗
PubMed2006

[Serum triglyceride distribution characteristics and their correlation with abnormal glucose metabolism in different ethnics in Ili Prefecture].

OBJECTIVE: To study the serum triglyceride (TG) distribution characteristics and their relation with abnormal glucose metabolism in populations of different nationalities in Ili Prefecture of Xinjiang Uygur Autonomous Region to provide a basis for extending the prevention and treatment of abnormal glucose metabolism. METHODS: With stratified cluster sampling method, epidemiological survey was conducted together with tests blood lipid and abnormal blood glucose metabolism among the permanent resident populations of six major nationalities, i.e Kazak, Uygur, Han, Hui, Xibe and Mongolia; they account for 96.8% of the total population in Ili Prefecture. In the meantime of conducting questionnaire survey and physical examination, blood glucose and blood lipid levels of the surveyed subjects were examined. RESULTS: Among all the people surveyed in Ili Prefecture, the prevalence of hypertriglyceridemia was 36.10%, being higher in urban than in rural areas and higher in males than females (P < 0.001). The prevalence of hypertriglyceridemia in Uygur and Han people (51.73% and 46.56%) was higher than that of Kazak and Mongolian people (16.39% and 18.42%). The prevalence of hypertriglyceridemia increased with the increase of age to different extent (RR value: 1.10 - 2.48). The prevalence of abnormal glucose metabolism also increased with the increase of blood TG levels. CONCLUSION: The levels of serum triglyceride in the population of different nationalities in Ili Prefecture are different in different nationalities, areas, ages and sexes. In those with hypertriglyceridemia, the prevalence of abnormal glucose metabolism increases also.

Adult↗