Search PubMed⌕ Search

Biomedical subjects

Lin Yang

Publications and source records attributed to Lin Yang.

At least 91 records · Page 5Linked to original sources
PubMed2005

Biotransformation of alpha-santonin by cell suspension cultures of five plants.

Cell suspension cultures of five plants (Catharanthus roseus, Ginkgo biloba, Platycodon grandiflorum, Taxus cuspidata, Phytolacca asinosa) were employed to bioconvert the eudesmanolide compound, alpha-santonin. Reactions occurring were hydroxylation (C-1, C-11 and C-15), reduction of the double bond [1(2) or 3(4)], rearrangment of the eudesmanolide skeleton to a guaianolide skeleton and lactone-ring hydrolysis. Four new compounds were identified.

Biotransformation↗
PubMed2005

Molecular orientation of collagen in intact planar connective tissues under biaxial stretch.

Understanding of the mechanical behavior of collagenous tissues at different size scales is necessary to understand their physiological function as well as to guide their use as heterograft biomaterials. We conducted a first investigation of the kinematics of collagen at the molecular and fiber levels under biaxial stretch in an intact planar collagenous tissue. A synchrotron small angle X-ray scattering (SAXS) technique combined with a custom biaxial stretching apparatus was used. Collagen fiber behavior under biaxial stretch was then studied with the same specimens using small angle light scattering (SALS) under identical biaxial stretch states. Both native and glutaraldehyde modified bovine pericardium were investigated to explore the effects of chemical modification to collagen. Results indicated that collagen fiber and molecular orientation did not change under equibiaxial strain, but were observed to profoundly change under uniaxial stretch. Interestingly, collagen molecular strain initiated only after approximately 15% global tissue strain, potentially due to fiber-level reorganization occurring prior to collagen molecule loading. Glutaraldehyde treatment also did not affect collagen molecular strain behavior, indicating that chemical fixation does not alter intrinsic collagen molecular stiffness. No detectable changes in the angular distribution and D-period strain were found after 80 min of stress relaxation. It can be speculated that other mechanisms may be responsible for the reduction in stress with time under biaxial stretch. The results of this first study suggest that collagen fiber/molecular kinematics under biaxial stretch are more complex than under uniaxial deformation, and warrant future studies.

Animals↗
PubMed2005

ST-segment elevation in the early repolarization syndrome, idiopathic ventricular fibrillation, and the Brugada syndrome: cellular and clinical linkage.

ST-segment elevation in a structurally normal heart is associated with an electrocardiographic (ECG) J wave, which can be observed in the early repolarization syndrome (ERS), idiopathic ventricular fibrillation (VF), and the Brugada syndrome. Animal studies have demonstrated that the J wave is the consequence of a transmural voltage gradient resulting from an Ito-mediated action potential notch (spike and dome) in epicardium but not endocardium. Ito-mediated spike and dome morphology predisposes loss or depression of the dome in epicardium, leading to ST-segment elevation. Despite the fact that 3 clinical syndromes share many common ECG features, their clinical consequences are remarkably different. The ERS is a benign ECG finding characterized by a distinct J wave and ST segment in left precordial leads V4 through V6. In contrast, idiopathic VF and the Brugada syndrome, characterized by a J wave and ST-segment elevation in the inferior and right precordial leads, respectively, are the leading causes for sudden cardiac death in young Southeast Asian males. The underlying mechanism for such a difference in clinical consequences among these syndromes is due to a difference in Ito density and Ito-mediated epicardial spike and dome. When Ito is prominent, complete loss of the dome may occur due to either a decrease in inward currents or an increase in outward currents, leading to phase 2 reentry capable of initiating VF as in idiopathic VF and the Brugada syndrome. When Ito is relatively small as in the ERS, partial depression of the dome occurs without the development of phase 2 reentry.

Animals↗
PubMed2005

Alpha-linolenic acid but not conjugated linolenic acid is hypocholesterolaemic in hamsters.

Conjugated linolenic acid (CLN) refers to a group of octadecatrienoic acid isomers that have three double bonds in conjugation. Both pomegranate and tung seed oils are rich in CLN but the major isomer in the former is cis9,trans11,cis13 while in the latter it is cis9,trans11,trans13. The present study examined the effects of CLN, isolated from either pomegranate seed oil or tung seed oil, and alpha-linolenic acid (LN), isolated from flaxseed oil, on serum cholesterol levels in male hamsters (body weight 105 g; age 10 weeks) fed a 0.1% cholesterol and 10% lard diet, for a period of 6 weeks. All hamsters were allowed free access to food and fluid. The blood samples were taken by bleeding from the retro-orbital sinus into a heparinized capillary tube under light ether anaesthesia after overnight fasting at weeks 0, 2, 4 and 6. It was found that supplementation of CLN at levels of 12.2-12.7 g/kg diet exhibited no significant effect on serum cholesterol level while LN at a similar level of supplementation had serum cholesterol reduced by 17-21% compared with the control diet containing no LN and CLN. Supplementation of CLN and LN significantly decreased hepatic cholesterol but no effect was observed on heart and kidney cholesterol levels. It was concluded that LN possessed hypocholesterolaemic activity while CLN had no effect on blood cholesterol, at least in hamsters.

Animals↗
PubMed2005

Unsupervised segmentation based on robust estimation and color active contour models.

One of the most commonly used clinical tests performed today is the routine evaluation of peripheral blood smears. In this paper, we investigate the design, development, and implementation of a robust color gradient vector flow (GVF) active contour model for performing segmentation, using a database of 1791 imaged cells. The algorithms developed for this research operate in Luv color space, and introduce a color gradient and L2E robust estimation into the traditional GVF snake. The accuracy of the new model was compared with the segmentation results using a mean-shift approach, the traditional color GVF snake, and several other commonly used segmentation strategies. The unsupervised robust color snake with L2E robust estimation was shown to provide results which were superior to the other unsupervised approaches, and was comparable with supervised segmentation, as judged by a panel of human experts.

Algorithms↗
PubMed2005

[Bcl-xl blocks tumor necrosis factor alpha-induced caspase 8 activation and apoptosis].

OBJECTIVE: To explore the effect of Bcl-xl on tumor necrosis factor-alpha (TNFalpha)-induced apoptosis signal pathway and apoptosis. METHODS: A dominant negative mutant of ikB (pmi kappaB) and Green Fluorescent Protein (GFP) expression plasmid pEGFP-C1, pmi kappab and pEGFP-C1 and Bcl-xl expression construct pBcl-xl/HA, were co-transfected into HeLa cells. Expression plasmid pBcl-xl/HA was introduced into p65-/-MEF cells in which nuclear factor-kappaB (NF-kappaB)/p65 was deficient, to establish cell line p65-/-Bcl-xl expressing Bcl-xl by selection with puromycin. These cells were treated with TNFalpha at a concentration of 10 ng/ml, and apoptotic cell death was examined microscopically with trypan blue staining. The proteins were abstracted from treated cells, and caspase 8 activation and cleavage of poly (ADP-ribose) polymerase (PARP) were examined by western blot using a specific antibody that recognized cleaved caspase 8 and cleaved PARP, respectively. RESULTS: HeLa cells transfected with pmi kappaB, TNFalpha showed significant cell death as they became rounded, shrank, and detached. However in HeLa cells co-transfected with pBcl-xl and pmi kappaB, no cell death was observed after treatment with TNFalpha. In p65-/- MEF cells; cell death was observed at 4 hours after treatment with TNFalpha, and cell death reached 90% at 12 hours after the treatment. However, in p65-/-Bcl-xl/HA cells expressing Bcl-xl, no cell death was seen even when treated with TNFa for 24 hours. Meanwhile, in pmikB/HeLa cells transfected with pmi kappaB, TNFalpha induced caspase 8 activation and PARP cleavage, but in the HeLa cells co-transfected with pBcl-xl and pmi kappaB, no activated caspase 8 and cleaved PARP were observed after treatment with TNFalpha. CONCLUSION: In the experimental system in which NF-kB was inhibited, Bcl-xl blocked TNFalpha-induced apoptosis signal pathway and apoptosis. These results bring to light that further studies of the pathogenesis and therapy of TNFa-related diseases are needed.

Apoptosis↗
PubMed2005

[Mathematical model of cardiac action potential and its computer simulations].

Malignant arrhythmias and ventricular fibrillation are generally accepted as one of the major causes of death in cardiovascular diseases. Based on the H-H equations, the mathematical model of the cardiac cell action potential consists of the ion channels, pumps, exchangers and transporters that are closely connected with intra- and extra-cellular ion concentrations, the channel's conditions, nerve transductors and drugs. It can build the link between cell electrophysiology and clinical pathophysiology. By altering the cellular environments the computer simulating study on this kind of model can help us look into the electrophysiological changes of the cardiac tissue and even the whole heart and investigate the mechanisms of the cardiac arrhythmias as well. The components of the model and its computer simulating study are introduced in the paper.

Action Potentials↗
PubMed2005

[Study on IR of interaction of three modified-starchs and crystallization of calcium carbonate].

Three types of CaCO3 can be synthesized through biomimetic synthesis. In the present work, carboxymethyl-starch, etherified-starch, and phosphate-starch, used as organic matrices, were studied by FTIR. The result shows that the intensity of C-O peaks of the three modified-starchs changed. In addition, the intensity of C-O peaks was weakened or vanished obviously with the increase in time. The action mechanism of the modified-starchs and CaCO3 was briefly discussed.

Calcium↗
PubMed2005

[Detection of CBFbeta/MYH11 fusion transcripts and study of the mechanism of leukemogenesis of CBFbeta/SMHHC fusion protein].

OBJECTIVE: To explore CBFbeta/MYH11 fusion transcripts and its expressing product CBFbeta/SMHHC fusion protein in mechanism of leukemogenesis. METHODS: CBFbeta/MYH11 fusion transcripts were detected by combined RT-PCR with sequencing. Transcription assays were examined using pM-CSFR-Luc as reporting plasmid, and subcellular localization of encoding proteins were assayed by double immunofluorescent staining and Western blot. RESULTS: Two types of CBFbeta/MYH11 fusion transcripts were found in 26 patients with acute leukemia, most being of type A (23/26 cases, 92%) and a few of type D (2/26 cases, 8%). The inhibition of CBF-mediated M-CSFR promotor transactivation by CBFbeta/SMHHC fusion protein was increasing with the increase in amount of the fusion protein. CBFalpha subunit (AML1) located in nucleus, both CBFbeta subunit (CBFbeta) and CBFbeta/SMHHC located in cytoplasm. When AML1 and CBFbeta were coexpressed, CBFbeta still located mainly in cytoplasm, but when AML1 and CBFbeta/SMHHC were coexpressed, CBFbeta/SMHHC located mainly in nucleus. CONCLUSIONS: (1) The types of CBFbeta/MYH11 fusion transcripts of Chinese leukemia patients are almost the same as that reported in western literature. (2) CBFbeta/SMHHC inhibits CBF-mediated transactivation through competing with CBFbeta for binding to AML1.

Adult↗
PubMed2005

[Clinical study of feiyanqing rectum condensed liquid in treating 36 cases of children syncytial viral pneumonia].

OBJECTIVE: To evaluate the clinical efficacy and mechanism of Feiyangqin Rectum Condensed Liquid (FRCL) in treating children syncytial viral pneumonia. Methods Seventy-two patients were randomly divided into two groups, the 36 patients in the treated group were treated with FRCL, and the other 36 patients in the control group simply treated with Western medicine. Efficacy of treatment on clinical condition and some immune function (IgA, IgG, CD3, CD4) were observed. RESULTS: In the treated group, 28 patients were cured (77.8%), treatment was markedly effective in 4 patients (11.1%), effective in 2 (5.5%) and ineffective in 2 (5.6%), with the total effective rate of 94.4%. The corresponding number in the control group was 20 (55.6%), 7 (19.4%), 6 (16.7%), 3 (8.3%) and 91.7%, respectively. The cure rate in the treated group was obviously superior to that in the control group (P < 0.05). FRCL could improve serum IgA, IgG, CD3, CD4, and CD4/CD8, lower serum IgE, these indexes in the treated group were significantly different to those in the control group (P < 0.05). CONCLUSION: FRCL had the action in treating children syncytial viral pneumonia without any adverse reaction, one of its mechanisms might be related to its regulation on immune function.

Administration, Rectal↗
PubMed2005

Biotransformation of 6beta-santonin by Phytolacca acinosa cell suspension cultures.

AIM: To obtain more valuable derivatives for the further structural modification of 6beta-santonin (1) via biotransformation by using cell suspension cultures of Phytolacca acinosa. METHODS: The substrate 1 was incubated with cell suspension cultures of P. acinosa, the products were obtained by chromatography, and identified on the basis of their physical and spectral data (HRMS, 1D NMR, 2D NMR, NOE and IR). RESULTS: After incubation with cell suspension cultures of P. acinosa, 1 was converted into five products. Among them, 3 is a new compound. CONCLUSION: 6beta-santonin could be selectively reduced and hydroxylated by the cell suspension cultures of P. acinosa, which would provide valuable intermediates for its further structural modification.

Biotransformation↗
PubMed2005

Comparative study of expressions of cytoplasmic CD79a and other B-lymphoid immunomarkers in acute leukemic cells.

To evaluate the expression of cytoplasmic CD79a (CyCD79a) and other commonly used B-lymphoid immunomarkers including cytoplasmic CD22 (CyCD22), CD19, CD20 and CD10 in various acute leukemia cells and to define the most sensitive and specific markers in the diagnosis of precursor B-cell acute lymphoblastic leukemia (pB-ALL), the immunophenotypic data from 221 de novo adult and pediatric acute leukemia patients as studied using multi-parameter flow cytometry in addition to routine morphologic and enzyme cytochemical assay, were retrospectively analyzed. Cytogenetic and/or molecular biological data in all 45 cases of acute promyelocytic leukemia (APL) and 13 cases of acute leukemia suspected as AML with the fusion genes such as AML1/ETO and CBFbeta/MYH11 were investigated. The results showed that CyCD79a and CyCD22 were the most sensitive and specific markers respectively for pB-ALL. Expression of CyCD79a was seen in 100% of 58 cases of pB-ALL. At the same time, none (0%) of all 147 cases of acute myeloid leukemia (AML) and 15 cases of precursor T-cell acute leukemia (pT-ALL) was positive for CyCD22. The conclusion is made that united detection of CyCD79a and CyCD22 is the optimal immune combination for the diagnosis pB-ALL and the distinguishing pB-ALL with AML and pT-ALL.

Acute Disease↗
PubMed2005

[Postoperative respiratory failure in patients with cancer of esophagus and gastric cardia].

OBJECTIVE: We retrospectively analyzed the cause and death risk of 114 postoperative respiratory failure patients found in 3519 patients with esophageal cancer and 1495 patients with carcinoma of gastric cardia surgically treated between January 1992 and May 2003. METHODS: To analyze the reasons causing postoperative respiratory failure in surgically treated esophageal or gastric cardia cancer patients, and the correlation between the death risk of postoperative respiratory failure and preoperative pulmonary function tests, postoperative complications, operation modes, history of preoperative accompanying diseases and so on using Binary Logistic Regression analysis and Chi-square tests (chi(2)) in SSPS statistics software. RESULTS: In this series, postoperative respiratory failure developed in 97 of 3519 (2.76%) esophageal cancer patients and 17 of 1495 (1.14%) gastric cardia cancer patients, which were mainly caused by severe respiratory tract infection (37.7%, 43/114) and operative complications (35.1%, 40/114) such as: anastomotic leakage or perforation of thoracic stomach, extensive bleeding during operation, chylothorax, etc, totally accounting for 72.8% (83/114). In contrast with lung cancer patients, most of the postoperative respiratory failure (69.3%) occurred in the patients who had perioperative complications but almost always normal preoperative pulmonary function tests. Other reasons to cause postoperative respiratory failure were: extubation in unconscious patients at the end of general anesthesia; over-infusion during operation; pulmonary artery embolism; severe arrhythmia and so on. All patients except 2 were treated in ICU by mechanic ventilation through intubation and/or tracheotomy. Eighty patients (70.2%) were intubated and/or had tracheotomy within 3 days postoperatively. Seventy patients (61.4%) were rescued successfully, whereas 44 cases (38.6%) died of postoperative respiratory failure and/or other postoperative complications. Univariate analysis and multivariate analysis by binary logistic regression indicated that: severe perioperative complications, more postoperative complications, poor preoperative pulmonary function, radical preoperative radiotherapy, intubation and/or tracheotomy after the second postoperative day and long period of mechanic ventilation were the major risk factors leading to death once the postoperative respiratory failure developed. The former 3 factors were independent risk factors leading to death with OR of 2.50, 2.37, 1.68, respectively. Age, sex, operation modes, history of preoperative accompanying disease, prophylactic antibiotics were not demonstrated as statistically significant risk factors correlated with death. CONCLUSION: Severe perioperative complications and respiratory tract infection are the two major causes of postoperative respiratory failure in patients with cancer of esophagus and gastric cardia. Patients with severe perioperative complications or poor preoperative pulmonary function or association with more than two kinds of postoperative complications have much higher death risk than other patients when they develop postoperative respiratory failure. Careful manipulation during operation and effective perioperative management are the most important measures to avoid postoperative respiratory failure and high mortality.

Adult↗
PubMed2005

[Study on the postive frequency and distribution of glutamic acid decarboxylase antibody in phenotypic type 2 diabetec patients].

OBJECTIVE: To investigate the positive frequency and distribution of glutamic acid decarboxylase antibody(GAD-Ab) in phenotypic type 2 diabetic(T2DM) patients. METHODS: Sera of 2035 phenotypic T2DM patients were screened for GAD-Ab with radioligand assay. The positive frequency of GAD-Ab and its relation with clinical features were analyzed. RESULTS: (1) The positivity of GAD-Ab in clinic-based, phenotypic T2DM patients was 7.1% (145/2035), comparable to that of data from Caucasians as shown by UKPDS(8.7% vs. 9.8%, P = 0.391) and ADOPT (8.0% vs. 4.2%, P = 0.000) but higher than that of Japanese in Ehime study(7.1% vs. 3.8%, P = 0.000). (2) The positive frequency and distribution of GAD-Ab titer were related to clinical features, including age at onset, body mass index (BMI) and fasting C peptide levels. Patients with younger age at onset (0.33 vs. 0.11, P < 0.05), less BMI (0.34 vs. 0.10, P < 0.05) and lower C peptide levels (0.38 vs. 0.11, P < 0.05) would have higher GAD-Ab titers. CONCLUSION: (1)The positivity of GAD-Ab in adult-onset phenotypic T2DM in Chinese was similar to that of Caucasians but higher than that of the Japanese. (2) The distribution of GAD-Ab titers was associated with clinical features, with high GAD-Ab titers for those having younger age at onset, less BMI and lower C peptide levels.

Adolescent↗
PubMed2005

[Investigation of GSTT1, GSTM1 and NQO1 genes polymorphisms in myelodysplastic syndromes].

OBJECTIVE: To investigate the relationship between GSTM1, GSTT1 and NQO1(C609T) genotypes and myelodysplastic syndromes (MDS) susceptibility and chromosome abnormalities. METHODS: GSTT1, GSTM1 and NQO1(C609T) genotypes were detected in 52 MDS patients and 241 unrelated controls by PCR or PCR-RFLP. RESULTS: The incidence of GSTT1 and GSTM1 null genotype was significantly increased in MDS patients as compared with controls (P = 0.001 and P < 0.001, respectively). In individuals with GSTT1 and GSTM1 null genotype, the odds ratios for MDS risk were elevated to 2.873 (95% CI: 1.491-5.537) and 3.591 (95% CI: 1.717-7.508), respectively. A significantly increased frequency of GSTT(1) null genotype among MDS patients with normal karyotype and increased frequency of GSTM1 null genotype among MDS patients with chromosome abnormalities were found as compared to controls (OR = 5.336, P = 0.005 and P = 0.003, OR = 3.740, respectively). There was no difference in the incidence of NQO1(C609T) genotypes between MDS patients and controls. CONCLUSION: Determination of the GSTM1 and GSTT1 genotypes may be used as a stratification marker to predicate high-risk individuals for MDS.

Adolescent↗