PubMed Health⌕ Search

Biomedical subjects

Yun Li

Publications and source records attributed to Yun Li.

At least 73 records · Page 4Linked to original sources
PubMed2005

[The value of mediastinoscopy in the diagnosis of thoracic sarcoidosis].

OBJECTIVE: To evaluate the role of mediastinoscopy in the diagnosis of thoracic sarcoidosis. METHODS: This study was retrospective. Mediastinoscopy was performed in a total of 30 patients who had enlarged mediastinal lymph nodes on chest CT and were clinically suspected of having sarcoidosis from November 1999 to June 2004. Biopsy tissues from peritracheal, retrosternal, subcarinal, or bilateral hilar regions were obtained for pathological study. RESULTS: All the patients had a definitive pathologic diagnosis, consisting of 24 cases of stage I and 6 stage II thoracic sarcoidosis. The diagnostic consistency between preoperation and postoperation was 40% (12/30), and the misdiagnosis rate preoperation was 60% (18/30). In this series, the initial diagnosis had been malignancy in 17 cases (57%), of whom 3 had received chemotherapy at local hospitals. The overall incidences of postoperative complication and mortality were 0. CONCLUSION: Our experience showed that mediastinoscopy is a valuable procedure which helps confirm the diagnosis of mediastinal disease. Given its safety and efficacy, it should be considered in the diagnosis and differential diagnosis of thoracic sarcoidosis of stage I or II.

Adult↗
PubMed2005

Circulating levels of nitric oxide and vascular endothelial growth factor throughout ovine pregnancy.

Nitric oxide (NO) production has been shown to increase uterine blood flow and be elevated in ewes carrying multiple fetuses during late gestation. Vascular endothelial growth factor (VEGF) has been reported to increase eNOS expression and NO production in endothelial cell cultures. As angiogenesis and vasodilatation of the uterine and placental vascular beds are important at all stages of pregnancy, it is important to understand how VEGF and NO change throughout gestation in circulation. Therefore the objectives of the current study were to evaluate the systemic levels of VEGF and NO metabolite (NOx) throughout ovine gestation and to determine if there was an effect of sheep carrying singletons versus multiple fetuses. NOx and VEGF concentrations were analysed in systemic blood from pregnant ewes starting on day 27 of pregnancy and at multiple intermittent intervals throughout pregnancy until term. Blood samples from non-pregnant and postpartum ewes were also analysed. NOx concentrations in maternal blood expressed a biphasic pattern with NOx concentrations increasing (P < 0.05) over non-pregnant values on days 40-69 of gestation, returning to non-pregnant concentrations from days 70-100, and again increasing (P < 0.05) until term. Postpartum NOx concentrations were similar to non-pregnant values. While ewes carrying multiple fetuses had increased (P < 0.05) concentrations of NOx on days 60-69, there were no differences in NOx concentrations in ewes carrying singletons or multiples from day 70-99 of gestation. Starting on day 100 and continuing throughout the duration of pregnancy, ewes carrying multiple fetuses had increased (P < 0.05) concentrations of NOx compared to ewes carrying singletons. Concentrations of VEGF showed a different pattern from NOx with VEGF decreasing (P < 0.05) from day 20-69 of pregnancy compared to non-pregnant ewes. Concentrations of VEGF returned to non-pregnant levels by day 70 and remained constant throughout the duration of pregnancy. On days 20-39, ewes carrying singleton fetuses had an increased VEGF concentration (P < 0.05), whereas ewes carrying multiple fetuses demonstrated elevated VEGF concentrations from day 90-109 of gestation. Concentrations from non-pregnant and postpartum ewes did not differ (P > 0.1). While there was no effect of fetal number on circulating VEGF concentrations, circulating levels of NOx were substantially increased (P < 0.05) in ewes carrying multiple fetuses, compared to ewes carrying singletons. The pattern of the rise in NOx in circulating plasma was not directly associated with changes in VEGF regardless of the number of fetuses present. However, circulating concentrations of NOx and VEGF appear to, respectively, follow patterns of uterine blood flow and angiogenesis of the uterus. An understanding of these circulatory patterns may have important implications for fetal size, birth weight and fetal/developmental origins of adult disease.

Animals↗
PubMed2005

Putative association between a new polymorphism in exon 3 (Arg109Cys) of the pancreatic colipase gene and type 2 diabetes mellitus in two independent Caucasian study populations.

The protein encoded by the pancreatic colipase (CLPS) gene is an essential cofactor needed by pancreatic triglyceride lipase (PNLIP) for efficient dietary lipid hydrolysis. Since the inhibition of lipase activity was shown to reduce the incidence of type 2 diabetes mellitus, we tested the hypothesis that genetic variations in the CLPS and PNLIP genes are associated with type 2 diabetes; 47 unrelated subjects were screened for polymorphisms of the CLPS and PNLIP genes. A nested-case control study of 192 incident type 2 diabetes subjects and 384 sex- and age-matched controls taken from the European Prospective Investigation into Cancer and Nutrition Potsdam Cohort (EPIC) was employed for association studies. The Metabolic Intervention Cohort Kiel (MICK) consisting of 716 males was used for verification. A novel putative functional polymorphism (Arg109Cys) was identified in the CLPS gene. The frequencies of the Arg/Cys genotype were 2.6% in EPIC and 2.2% in MICK study subjects. No homozygotes for the Cys/Cys genotype were found in either study population. Logistic regression analysis showed a statistically significant association of the Arg/Cys genotype with an increased risk of type 2 diabetes. The odds ratios estimated by the model were 3.75 (95%CI = 1.13-12.49, p = 0.03) in EPIC and 4.86 (95%CI = 1.13-20.95, p = 0.03) in MICK. No comparable associations were found with other traits of the insulin-resistance syndrome (e. g.; body mass index, waist to hip ratio). In conclusion, we obtained evidence in two German Caucasian study populations that the variant of the rare CLPS Arg109Cys polymorphism might contribute to increased susceptibility of type 2 diabetes.

Aged↗
PubMed2005

Influence of timing of troponin elevation on clinical outcomes and use of evidence-based therapies for patients with non-ST-segment elevation acute coronary syndromes.

STUDY OBJECTIVE: Previous studies in clinical trial populations have demonstrated that patients presenting with positive troponin levels have a higher risk of mortality than patients with later positive troponin levels, but the influence of the timing of troponin elevation has not been previously characterized. We evaluate the impact of the timing of troponin elevation on clinical outcomes and adherence to the American College of Cardiology/American Heart Association acute care guidelines for patients with non-ST-segment elevation acute coronary syndromes. METHODS: We examined inhospital outcomes and use of acute (<24 hours) medications and invasive cardiac procedures in 23,184 high-risk patients with non-ST-segment elevation acute coronary syndromes (positive cardiac markers or ischemic ST-segment changes) during 2001 to 2002 from 396 US hospitals participating in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress ADverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines (CRUSADE) Initiative. Baseline and peak troponin values were recorded and were designated as positive if above the cutoff value used at each institution to designate definite myocardial necrosis. RESULTS: In the study cohort, 53.2% of patients presented with baseline positive troponin levels, 30.6% had baseline negative/later positive troponin levels, and 16.2% had negative troponin levels during the entire hospitalization. Patients with baseline positive troponin levels had a higher risk of inhospital mortality than patients with baseline negative/later positive troponin levels (6.5% versus 4.1%) and were less likely to undergo early cardiac catheterization or percutaneous coronary intervention. The use of acute aspirin (in approximately 91% of patients), heparin (85%), and beta-blockers (78%) was similar in patients with baseline-positive versus later-positive troponin levels. CONCLUSION: These findings demonstrate that evidence-based therapies and interventions for non-ST-segment elevation acute coronary syndromes are underused in patients with elevated troponin levels, but baseline troponin elevations, which are associated with a higher risk of inhospital mortality, do not stimulate more aggressive care.

Acute Disease↗
PubMed2005

Multiple effects of hyperbaric oxygen on the expression of HIF-1 alpha and apoptotic genes in a global ischemia-hypotension rat model.

Hypoxia-inducible factor-1alpha (HIF-1alpha) is a transcription factor specifically activated by hypoxia. Activation of proapoptotic caspase-9 and caspase-3 pathways, by binding with tumor suppressor p53, HIF-1alpha could lead to harmful actions such as apoptosis. We examined whether increasing oxygen levels by hyperbaric oxygen (HBO) offers neuroprotection, at least partially by suppression of HIF-1alpha and apoptotic genes. Male SD rats (n = 78) were randomly divided into 13 groups: 1 sham group, 6 groups of global ischemia-hypotension (GI), and 6 groups of HBO treatment after global ischemia-hypotension (GI + HBO). HBO (3 ATA for 2 h) was applied at 1 h after global ischemia-hypotension. Rats were sacrificed at 6, 12, 24, 48, and 96 h and 7 days. Global ischemia-hypotension (10 min ischemia, 30-35 mm Hg) produced a marked increase of HIF-1alpha expressions in the hippocampus and cortex at 6 h and peaked at 48-96 h. The expressions of p53, caspase-9, and caspase-3 were all increased in a similar time course. These molecular changes were accompanied by massive cell loss in the hippocampal regions and to a lesser degree in the cortex, with features of apoptosis. HBO treatment reduced expressions of HIF-1alpha, p53, caspase-9, and caspase-3 and decreased cell death. The protein levels of proapoptotic caspase-8 and antiapoptotic bcl-2 were increased after global ischemia-hypotension and HBO potentiated the expression of caspase-8 and decreased expression of bcl-2. These results indicate that HBO has multiple actions on apoptotic genes even though the overall effect of HBO was decreased HIF-1alpha expression and reduced apoptosis after global ischemia-hypotension.

Animals↗
PubMed2005

A single gene directs both production and immunity of halocin C8 in a haloarchaeal strain AS7092.

Halocin C8 (HalC8) is an extremely stable and hydrophobic microhalocin with 76 amino acids, and has a wide inhibitory spectrum against the haloarchaea. It is derived from the C-terminus of a 283-amino-acid prepro-protein (ProC8), which was demonstrated by molecular cloning of the halC8 gene, and verified by the N-terminal amino acid sequencing as well as MALDI-TOF-MS analysis of the purified HalC8. The production of this halocin is controlled through both transcription regulation and protein processing: the halC8 transcripts and HalC8 activity rapidly increased to maximal levels upon transition from exponential to stationary phase. However, while halC8 transcripts remained abundant, the HalC8 processing was inhibited during stationary phase. Remarkably, agar-diffusion test revealed the unprocessed ProC8 and its 207-amino-acid N-terminal peptide (HalI), with or without the putative Tat signal sequence, were capable to block the halocin activity of HalC8 in vitro. In addition, heterologous expression of HalI in Haloarcula hispanica rendered this sensitive strain remarkable resistance to HalC8, indicating that HalI encodes the immunity property of the producer. In accordance with this immunity function, HalI and ProC8 were both found localized on the cellular membrane. Protein interaction assay revealed that HalI likely sequestrated the HalC8 activity by specific binding. To our knowledge, this is the first report on halocin immunity, and our results that a single gene encodes both peptide antibiotic and immunity protein also provide a novel immune mechanism for peptide antibiotics.

Amino Acid Sequence↗
PubMed2005

TAF1 histone acetyltransferase activity in Sp1 activation of the cyclin D1 promoter.

A missense mutation within the histone acetyltransferase (HAT) domain of the TATA binding protein-associated factor TAF1 induces ts13 cells to undergo a late G(1) arrest and decreases cyclin D1 transcription. We have found that TAF1 mutants (Delta844-850 and Delta848-850, from which amino acids 844 through 850 and 848 through 850 have been deleted, respectively) deficient in HAT activity are unable to complement the ts13 defect in cell proliferation and cyclin D1 transcription. Chromatin immunoprecipitation assays revealed that histone H3 acetylation was reduced at the cyclin D1 promoter but not the c-fos promoter upon inactivation of TAF1 in ts13 cells. The hypoacetylation of H3 at the cyclin D1 promoter was reversed by treatment with trichostatin A (TSA), a histone deacetylase inhibitor, or by expression of TAF1 proteins that retain HAT activity. Transcription of a chimeric promoter containing the Sp1 sites of cyclin D1 and c-fos core remained TAF1 dependent in ts13 cells. Treatment with TSA restored full activity to the cyclin D1-c-fos chimera at 39.5 degrees C. In vivo genomic footprinting experiments indicate that protein-DNA interactions at the Sp1 sites of the cyclin D1 promoter were compromised at 39.5 degrees C in ts13 cells. These data have led us to hypothesize that TAF1-dependent histone acetylation facilitates transcription factor binding to the Sp1 sites, thereby activating cyclin D1 transcription and ultimately G(1)-to-S-phase progression.

Acetylation↗
PubMed2005

Application of bioinformatics in search for cleavable peptides of SARS-CoV M(pro) and chemical modification of octapeptides.

According to the "distorted key" theory as elaborated in a review article years ago (Chou, K.C.: Analytical Biochemistry, 1996, 233, 1-14), the knowledge of the cleavable peptides by SARS-CoV M(pro) (severe acute respiratory syndrome coronavirus main proteinase) can provide very useful insights on developing drugs against SARS. In view of this, the softwares, ZCURVE_CoV 1.0 and ZCURVE_CoV 2.0 (http://tubic.tju.edu.cn/sars/), developed recently for SARS-Coronavirus are used to analyze the 36 complete SARS-Coronavirus RNA sequences in the gene bank NCBI (http://www.ncbi.nlm.nih.gov/) from different sources for protein coding genes, and to search for the cleavage sites of SARS-CoV M(pro) in polyproteins pp1a and pp1ab. A total of 396 cleavage points are found in the 36 SARS-Coronavirus and 11 cleavable octapeptides abstracted from the 396 cleavage sites. The statistical distributions of amino acids for the cleavable octapeptides at the subsites R4, R3, R2, R1, R1', R2', R3' and R4' are calculated. The cleavage-specific positions are on R2, R1 and R1', and the positions R3 and R4 are featured by some certain specificity for SARS-CoV M(pro). The structural characters of amino acid residues around the cleavage-specific positions are discussed. Two most promising octapeptides, i.e., NH(2)-ATLQ downward arrowAIAS-COOH and NH(2)-ATLQ downward arrowAENV-COOH, are selected to be the candidates for chemical modification, converting into the inhibitors of SARS-CoV M(pro). A possible strategy to convert a cleavable octapeptide by SARS enzyme into a drug candidate against SARS is elucidated.

Amino Acid Sequence↗
PubMed2005

[Effects of recombinant human growth hormone (GH) replacement therapy on bone metabolism in children with GH deficiency].

OBJECTIVE: To study the changes of bone turnover markers and bone mass in children with growth hormone (GH) deficiency before and after recombinant human GH replacement therapy. METHODS: Serum levels of bone turnover markers (OC, BAP and ICTP), IGF1 and distal radius bone mass (SOS SDS) of 37 cases with complete growth hormone deficiency (CGHD), 31 partial growth hormone deficiency (PGHD) and 31 age- and sex-matched healthy controls were measured. Twenty-nine patients received rhGH replacement therapy at dose of 0.03 mg/kg. day and the above parameters were measured every 3 or 6 months after treatment. RESULT: Compared with the control, baseline serum levels of BAP, ICTP and IGF1 in CGHD group were significantly decreased (P<0.05), so was IGF1 in PGHD group (P<0.05). Significantly positive correlation was found between IGF1 and ICTP (r=0.32, P=0.01) in CGHD group. There was no significant difference between GHD group and the control in other biochemical parameters. All bone turnover markers and IGF1 increased significantly in both CGHD and PGHD children after rhGH replacement therapy for 3 months (P<0.05). ICTP and IGF1 were increasing with the prolonged rhGH replacement therapy. A tendency of increase in distal radius SOS SDS was also seen after rhGH-treatment, though not statistically significant (P>0.05). CONCLUSION: Compared with the control, bone turnover markers BAP and ICTP are lower in children with CGHD, with lower IGF1 but unchanged bone mass in both CGHD and PGHD. All bone turnover markers can be significantly improved in GHD children after rhGH replacement treatment for 6 months, with a tendency of increase in bone mass.

Alkaline Phosphatase↗
PubMed2005

[The effect of gamma-aminobutyric acid in superoxide dismutase, peroxidase and catalase activity response to salt stress in maize seedling].

Salt stress induced Gamma-aminobutyric acid (GABA) accumulation in maize plants. The germination of maize seeds was inhibited seriously by NaCl treatment, while exogenous GABA reduced the inhibition of NaCl on the seeds germination. Effects on SOD, POD and CAT activity of GABA were detected. 1-2 mmol/L GABA induced the increase of the activity of SOD, POD and CAT about 20%. Because of SOD, CAT and POD are important protective enzymes which can eliminate active oxygen, so GABA can alleviate the damage of salt stress through promoting the activity of the protective enzyme system.

Catalase↗
PubMed2005

[Monoclonal antibodies prepared and used for detection of acute virus necrobiotic disease virus in scallop Chlamys farreri by indirect ELISA].

For developing monoclonal antibodies against acute virus necrobiotic disease (AVND) virus, mice of Balb/c strain were immunized with AVND virions which were isolated from the infected scallop Chlamys farreri. The spleen cells from immunized mice were then fused with NS-1 myeloma cells and the hybridomas were screened by means of enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). Finally, 4 stable MAbs of IgG isotype were obtained. Moreover, the combined position of these 4 MAbs to this virus was examined by immunogold electron microscopy (IEM). The results demonstrate that all 4 MAbs recognized epitopes on the envelope of the virions. Subsequently, a MAb-based ELISA was developed and used for detection of the infection rate and densities of the scallops which were sampled during different seasons from mid-April to mid-October, 2003. The result exhibited that both of the infection rate and infection densities sharply rose in mid-July and reached to the spikes, which right corresponds with their mortality during this period.

Animals↗
PubMed2005

[Study of large-volume electrokinetic injection of capillary zone electrophoresis by using transient isotachophoresis].

A sample pre-concentration method that combined field-amplified sample injection (FASI) induced by acetonitrile with transient isotachophoresis was applied to achieve effective concentration and the separation of cations in high-salt samples. Several important factors are discussed, such as buffer systems, terminating ions, column effective length and injection time of sample and terminating solution. A capillary column of 50 microm i. d. x 65 cm (effective length of 50 cm) was employed. Solutions of 400 mmol/L LiAc-HAc (pH 4.5) and 400 mmol/L beta-alanine-HAc (pH 4.5) were used as buffer solution and terminating electrolyte, respectively. The injection times of sample solution and terminating electrolyte were 270 and 90 s, respectively. Compared with conventional electrokinetic injection, the sensitivity of the proposed method was improved about 280-fold. The detection limits of propranolol and metoprolol achieved 2 x 10(-3) and 8 x 10(-3) mg/L, respectively.

Acetonitriles↗
PubMed2005

[Association of polymorphisms in ACE and CYP11B2 genes with antihypertensive effects of hydrochlorothiazide].

OBJECTIVE: To determine whether the blood pressure (BP) response to hydrochlorothiazide (HCTZ) was associated with the angiotensin converting-enzyme (ACE) I/D and aldosterone synthase (CYP11B2)-344T/C polymorphisms. METHODS: The BP response to HCTZ 12.5 mg once daily for 6 weeks was assessed in 829 subjects with mild or moderate essential hypertension, and compared across the ACE and CYP11B2 genotypes. RESULTS: Of the 829 enrolled subjects, 785 completed the study. The systolic BP response differed according to the ACE (DD 9.4 +/- 15.7 mm Hg, ID 4.8 +/- 16.3 mm Hg, and II 5.1 +/- 14.8 mm Hg, P < 0.01), but not the CYP11B2 genotype (P > 0.05). Subjects with the combination of ACE DD and CYP11B2 CC genotypes tended to have a more pronounced systolic BP reduction than the other genotypic combinations of these 2 genes. Multiple linear regression analyses showed that the ACE DD genotype and serum aldosterone concentration at baseline were associated with the systolic BP reduction after treatment. None of the genetic associations with changes in diastolic BP or mean arterial pressure reached statistical significance (P > 0.05). CONCLUSIONS: The present study suggested that the ACE DD genotype was associated with the systolic BP response to HCTZ, and that the subjects with the combination of ACE DD and CYP11B2 CC genotypes might have a better BP response to HCTZ than the other genotypic combinations of these 2 genes.

Adult↗
PubMed2005

[Combination effects of vitamin A and zinc on human's PMBC DNA damage in vitro].

OBJECTIVE: To study the combination effects of vitamin A (Vit. A) and zinc on human's PBMC DNA damage in vitro. Methods The PBMC from healthy volunteer was purification and cultured in the basic culture medium with Vit.A of 10(-4), 10(-5) and 10(-6) mol/L, or/and with Zn of 10(-6), 10(-5) 10(-4) and 10(-3) mol/L. The basic culture medium with K2Cr2O7 of 1 mmol/L was the male control. The damage of PBMC DNA was respectively examined by SCGE and the image analyzer measured the comet tail rate and length. The apoptosis of each group PBMC was detected by FCM. RESULTS: The overdose supplement of zinc and Vit. A can damage the PBMC DNA in vitro culture (P < 0.01), while the suitable supplement doesn't find. When the Vit. A supplement has been excessive, giving suitable zinc could repair the damage of DNA, but would expand the injured cell. While when the zinc supplement has been excessive, giving suitable Vit. A could protect the healthy cells, but would aggravate the damage degree of injured cell. CONCLUSION: In vitro culture, the overdose Vit. A and zinc supplement could damage the human's PBMC DNA significantly. This need more researches to provide.

Cells, Cultured↗
PubMed2005

[Recent pharmacological study on sanshengwan decoction].

OBJECTIVE: To investigate the pharmacological function of Sanshengwan decoction with modern medical and rheological techniques, and also to discuss the differences between injury blood stasis syndrome and yang deficiency blood stasis syndrome. METHOD: Animal model for injury blood stasis syndrome was found by bruise; Animal model for yang deficiency blood stasis syndrome was done by exhausting the animals in a - 15 degrees C freezer for 4 hours. RESULT: Blood fibrinogen content, platelet aggregation and blood coagulation time were significantly increased, plasma viscosity and blood coagulation slope was significantly decreased in injury blood stasis syndrome group. Blood fibrinogen content, platelet aggregation and blood coagulation time were dropped markedly. Blood coagulation slope was raised noticeably in yang deficiency blood stasis syndrome group. Sanshengwan decoction behaved very good effects on removing blood stasis on both of the two kinds of animal models. CONCLUSION: Though hemorheological index and experimental data in the two kinds of animal models were behaved statistically significance, but the experimental representative indexes were obviously difference. Sanshengwan the tipical herbal medicine for eliminating blood stasis syndrome showed significantly effects on both of the two kinds of animal models, but the effects on injury blood stasis syndrome group was better than the other animal model's.

Angelica sinensis↗
PubMed2005

[Analysis of TCR Vbeta clonotypes of T lymphocytes infiltrating in the joints of rats with collagen-induced arthritis].

AIM: To investigate the TCR Vbeta clonetypes of T lymphocytes infiltrating in the synovium of rats with collagen induced arthritis (CIA). METHODS: Type II collagen was used to induce arthritis in Lewis rats. CD4(+) and CD8(+) T lymphocytes in peripheral blood of the rats were analyzed by flow cytometry (FCM). Total RNA was extracted from rat joint tissues and TCR Vbeta clonotypes were identified by RT-PCR and single-strand conformation polymorphism (SSCP). Splenic lymphocytes from CIA rats were transferred into normal Lewis rats. TCR Vbeta clonotypes of T lymphocytes infiltrating in the joints of the recipient rats were also analyzed by RT-PCR/SSCP. RESULTS: FCM analysis of the T lymphocytes indicated that CD8(+) T lymphocytes decreased in CIA rats and the CD4(+)/CD8(+) T lymphocytes ratio was >2, which suggested that there was a disproportion of the T lymphocyte subsets in CIA rats. RT-PCR/SSCP analysis showed that TCR Vbeta5.2 and TCR Vbeta8.2 clonotypes predominated in the T lymphocytes infiltrating in the joints of CIA rats. T lymphocytes infiltrating in the joints of the recipient rats displayed the same TCR Vbeta clonotypes as those in the donor rats. CONCLUSION: CIA rats may have a limited number of dominant TCR Vbeta clonotypes of T lymphocytes accumulating in the synovium, of which TCR Vbeta5.2 and 8.2 predominate.

Animals↗