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Lin Zhang

Publications and source records attributed to Lin Zhang.

At least 325 records · Page 18Linked to original sources
PubMed2002

Generation of a syngeneic mouse model to study the effects of vascular endothelial growth factor in ovarian carcinoma.

Vascular endothelial growth factor (VEGF) performs multifaceted functions in the tumor microenvironment promoting angiogenesis, suppressing anti-tumor immune response, and possibly exerting autocrine functions on tumor cells. However, appropriate syngeneic animal models for in vivo studies are lacking. Using retroviral transfection and fluorescence-activated cell sorting, we generated a C57BL6 murine ovarian carcinoma cell line that stably overexpresses the murine VEGF164 isoform and the enhanced green fluorescent protein. VEGF164 overexpression dramatically accelerated tumor growth and ascites formation, significantly enhanced tumor angiogenesis, and substantially promoted the survival of tumor cells in vivo. In vitro, VEGF164 overexpression significantly enhanced cell survival after growth factor withdrawal and conferred resistance to apoptosis induced by cis-platin through an autocrine mechanism. VEGF/green fluorescent protein-expressing tumors were not recognized by the adaptive immune system. After vaccination, a specific anti-tumor T-cell response was detected, but tumor growth was not inhibited. This engineered murine carcinoma model should prove useful in the investigation of the role of VEGF in modulating the tumor microenvironment and affecting the complex interactions among angiogenesis mechanisms, anti-tumor immune mechanisms, and tumor cell behavior at the natural state or during therapy in ovarian carcinoma.

Animals↗
PubMed2002

Role of the proposed pore-forming segment of the Ca2+ release channel (ryanodine receptor) in ryanodine interaction.

In earlier studies we showed that point mutations introduced into the proposed pore-forming segment, GVRAGGGIGD (amino acids 4820-4829), of the mouse cardiac ryanodine receptor reduced or abolished high affinity [3H]ryanodine binding. Here we investigate the effects of these mutations on the affinity and dissociation properties of [3H]ryanodine binding and on ryanodine modification of the ryanodine receptor channel at the single channel and whole cell levels. Scatchard analysis and dissociation studies reveal that mutation G4824A decreases the equilibrium dissociation constant (K(d)) and the dissociation rate constant (k(off)), whereas mutations G4828A and D4829A increase the K(d) and k(off) values. The effect of ryanodine on single G4828A and D4829A mutant channels is reversible on the time scale of single channel experiments, in contrast to the irreversible effect of ryanodine on single wild-type channels. Ryanodine alone is able to induce a large and sustained Ca2+ release in HEK293 cells transfected with the R4822A or G4825A mutant cDNA at the resting cytoplasmic Ca2+ but causes little or no Ca2+ release in cells transfected with the wild-type cDNA. Mutation G4826C diminishes the functional effect of ryanodine on Ca2+ release but spares caffeine-induced Ca2+ release in HEK293 cells. Co-expression of the wild-type and G4826C mutant proteins produces single channels that interact with ryanodine reversibly and display altered conductance and ryanodine response. These results are consistent with the view that the proposed pore-forming segment is a critical determinant of ryanodine interaction. A putative model of ryanodine-ryanodine receptor interaction is proposed.

Amino Acid Sequence↗
PubMed2002

Accuracy and reliability of the endoscopic classification of portal hypertensive gastropathy.

BACKGROUND: There is no consensus regarding the endoscopic classification of the severity of portal hypertensive gastropathy. This study compared the accuracy and reproducibility of the 2-category classification system (2-CCS) with the 3-category classification system (3-CCS). METHODS: Ninety-eight endoscopic pictures of portal hypertensive gastropathy and 22 of nonspecific gastritis were selected. Eight duplicate sets were generated, each in a different random order. These were shown to 6 experienced endoscopists during 2 sessions 1 week apart with 4 slide sets at each session. Each picture was scored by using either the 2-CCS or 3-CCS. Kappa statistics and percent agreement were used to estimate the reproducibility and agreement. RESULTS: The mean percentage agreement among the 4 separate readings for each observer was significantly lower for the 3-CCS compared with the 2-CCS (mean [standard deviation] = 33.5% [8.9%] vs. 64.9% [9.1%]; p = 0.0001). The mean (SD) interobserver kappa values were 0.44 (0.03) for the 3-CCS and 0.52 (0.04) for the 2-CCS (p = 0.02), and the respective intraobserver kappa values were 0.43 (0.1) and 0.63 (0.06) (p = 0.002). CONCLUSIONS: Even though both the 2-CCS and 3-CCS have substantial limitations with regard to specificity and reliability, there were better agreement and reproducibility with the simpler classification system for portal hypertensive gastropathy.

Gastric Mucosa↗
PubMed2002

Decreased thyroid uptake of Tc-99m pertechnetate in patients with advanced-stage Sjögren syndrome: evaluation using salivary gland scintigraphy.

PURPOSE: The authors assessed the uptake of Tc-99m pertechnetate in the thyroid using salivary gland scintigraphy in patients with Sjögren syndrome and in healthy controls. MATERIALS AND METHODS: Salivary gland scintigraphy and a labial biopsy were performed in 73 patients with Sjögren syndrome. Based on the labial biopsy findings, 32 patients with a histopathologic grade of 1 or 2 were regarded as having early-stage Sjögren syndrome and 41 patients with a grade of 3 or 4 were regarded as having an advanced stage. After the administration of 370 MBq (10 mCi) Tc-99m pertechnetate, dynamic salivary gland scintigraphy was performed for 50 minutes. Lemon juice was used to stimulate the salivary glands, and the thyroid gland was included in the imaging area. Scintigraphy was also performed in an age- and sex-matched control group of 25 healthy persons. The thyroid uptake ratio was calculated for the scintigraphic images and compared among the three groups: healthy controls, patients with early-stage Sjögren syndrome, and those with advanced-stage Sjögren syndrome. RESULTS: When compared with the control group, the thyroid uptake ratio of the early-stage Sjögren syndrome group was not significantly different, whereas that of the advanced-stage group was significantly lower. CONCLUSIONS: Thyroid uptake of Tc-99m pertechnetate was less in patients with advanced-stage Sjögren syndrome than in patients with early-stage Sjögren syndrome or in healthy controls. Measuring the thyroid uptake of Tc-99m pertechnetate using salivary gland scintigraphy is an easy and useful method for assessing thyroid disorders in Sjögren syndrome and thus should be performed routinely.

Adolescent↗
PubMed2002

[Study on the construction of standard D12S391 allelic ladder and its genetic polymorphism in six populations].

OBJECTIVE: To resolve the problem of the accuracy and standardization of short tandem repeat-polymerase chain reaction (STR-PCR) typing in forensic practice, the authors have designed a new method of producing standard D12S391 allelic ladder. METHODS: Nine different PCR amplified D12S391 allelic fragments were isolated from the gel, eluted into the distilled water and re-amplified by PCR. The purified allelic fragments were then blunt-end subcloned individually into the pUC plasmid vectors and transfected into competent E.coli DH5 alpha(TM) cells. The sequencing results confirmed that the size and the structure of the inserts were correct. The recombinant plasmids DNA with 9 inserts were then used as templates for PCR re-amplification to generate D12S391 standard ladder. RESULTS: With the ladder, the authors studied the genetic polymorphisms of D12S391 locus in six populations (German, Japanese and Chinese south-western Han, northern Han, Weiwu'er and Hui populations), and the respective primary data in the six populations were obtained. D12S391 locus showed high polymorphism in all six populations, and its exclusion power and discrimination power are 0.609-0.786 and 0.940-0.952 respectively. CONCLUSION: The results demonstrate that the standard ladder generated via this method is excellent, and D12S391 locus is robust for genetic research and forensic application.

Alleles↗
PubMed2002

Remove volatile organic compounds (VOCs) with membrane separation techniques.

Membrane separation, a new technology for removing VOCs including pervaporation, vapor permeation, membrane contactor, and membrane bioreactor was presented. Comparing with traditional techniques, these special techniques are an efficient and energy-saving technology. Vapor permeation can be applied to recovery of organic solvents from exhaust streams. Membrane contactor could be used for removing or recovering VOCs from air or wastewater. Pervaporation and vapor permeation are viable methods for removing VOCs from wastewater to yield a VOC concentrate which could either be destroyed by conventional means, or be recycled for reuse.

Bioreactors↗
PubMed2002

Autoantibodies against the myocardial beta1-adrenergic and M2-muscarinic receptors in patients with congestive heart failure.

OBJECTIVE: To determine whether autoantibodies against beta(1)-adrenergic and M(2)-muscarinic receptors are related to patients with congestive heart failure (CHF). METHODS: Both synthetic peptides corresponding to amino acids sequence 197-222 and 169-173 of the second extracellular loops of the beta(1) and M(2) receptors were used as antigens to screen sera from 265 patients.188 were congestive heart failure ( CHF) patients with different heart diseases, among them 42 were ischemic cardiomyopathy (ICD) and 52 were idiopathic dilated cardiomyopathy (IDCM) 44 were hypertensive heart disease (HHD) 50 were rheumatic valvular heart disease (RVHD); 77 were controls, among them 36 were simple hypertension and 41 were healthy donors (NC). RESULTS: Positive sera for beta(1)-adrenergic receptor was found in 45.73% (86/188) of CHF patients, while in the controls it was 10.4% (8/77) (P < 0.01); positive sera for M(2)-muscarinic receptor in CHF patients was found in 49.5% (99/188), while in the control it was 11.7% (9/77) (P < 0.01). The positive ratio of autoantibodies against beta(1)-adrenergic and M(2)-muscarinic receptors in CHF patients with cardiac function class II-III (NYHA) were significantly higher than cardiac function class IV. The average titer of autoantibodies against beta(1)-adrenergic and M(2)-muscarinic receptors of the former was significantly higher than the latter; 56.1% of patients with autoantibodies against beta(1)-adrenergic receptor had autoantibodies against M(2)-muscarinic receptor. CONCLUSIONS: Autoantibodies against beta(1)-adrenergic receptor and M(2)-muscarinic receptor were found in sera from heart failure patients with different cardiac diseases. We propose that autoantibodies against beta(1) and M(2) receptors are not only related to the IDCM, but also to cardiac structural and functional changes.

Adult↗
PubMed2002

Expression and purification of human endostatin in Pichia pastoris and its inhibition on the growth of mouse pulmonary adenocarcinoma cell line LA795.

OBJECTIVE: To obtain yeast strain Pichia pastoris that highly expresses human endostatin by gene recombination technology, and to evaluate the inhibitory effect of recombinant human endostatin (rhES) on the growth of mouse pulmonary adenocarcinoma cell line LA795. METHODS: The gene coding for human endostatin was cloned into the genome of Pichia pastoris through LiCl transformation method, and the clones with high soluble rhES expression were selected. Purification of rhES was performed with heparin affinity chromatography. Effects of rhES on bFGF-induced proliferation of human endothelial cell line ECV-304 cells were observed. T739 mice with subcutaneous inoculation of LA795 cells were treated with injections of either rhES or PBS for 14 consecutive days, and the volume of the tumors were measured. RESULTS: Clones with high rhES expression were obtained and purified rhES potently inhibited the proliferation of ECV-304 cells and the growth of LA795 cells in T739 mice. CONCLUSION: rhES produced by Pichia pastoris possesses good biological activities and conspicuously inhibits the growth of LA795 cells.

Adenocarcinoma↗
PubMed2002

[Inhibitory effects of endostatin on interleukin-6 and interleukin-8 release by human umbilical vein endothelial cells].

OBJECTIVE: To investigate the inhibitory effects exercised by endostatin on the production of interleukin-6 (IL-6) and IL-8 by human umbilical vein endothelial cells (HUVECs). METHODS: (HUVECs were isolated and cultured in vitro with endostatin (treated group) or PBS (control group), and the supernatant was harvested from the primary culture medium daily for 9 consecutive days starting from the first day of culture, followed by centrifugation. IL-6 and IL-8 contents in the supernatant were measured using sandwich enzyme-linked immunosorbent assay (ELISA). RESULTS: IL-6 and IL-8 were detected in the supernatant of the control cell culture, and their amounts increased as the cell culture was prolonged, reaching the peak levels on day 6 (2 979.32+/-19.65 pg/ml and 6 018.87+/-56.74 pg/ml, respectively). In the treated group, however, the amounts of IL-6 and IL-8 were significantly lower than the control levels (P<0.01). CONCLUSION: Endostatin can inhibit the growth and proliferation of endothelial cells, reducing their biological activities.

Angiogenesis Inhibitors↗
PubMed2002

[T(1) carcinoma of the lung: characteristics of lymph node metastasis and its clinical significance].

OBJECTIVE: To investigate the frequency, distribution and features of lymph node metastasis in T(1) carcinoma of the lung, and to provide evidence for lymph node dissection. METHODS: Two hundred and fifteen patients with T(1) carcinoma of the lung underwent R2 surgery plus extended dissection of hilar, interlobular and mediastinal lymph nodes according to the mapping system developed by Naruke. RESULTS: 1 674 groups of lymph nodes were dissected. The metastatic rates of N(1) and N(2) were 11% and 6% respectively. Lymph node metastatic rates in carcinoma of the lung with maximum diameters less than 1.5 cm and between 1.6 cm approximately 3.0 cm were 5% and 8% respectively. N(1) and N(2) metastasis was not found in squamous cell carcinoma of the lung with a maximum diameter less than 1.5 cm. N(2) metastatic rates were 5% in squamous cell carcinoma 23% in adenocarcinoma and 3/9 in small cell carcinoma, the difference being significant (P < 0.01). 3/4 squamous cell carcinoma invaded only one group of N(2) nodes, but over 3 groups of lymph nodes were positive in 40% of adenocarcinoma. Saltatory metastasis accounted for 41% of N(2) metastasis. Fourteen percent of N(2)-positive tumors in upper lobes metastasized to the lower mediastinum, whereas 60% of N(2)-positive cancers in lower lobes invaded the upper mediastinum. CONCLUSIONS: The frequency of lymph node metastasis increases with the growth of tumors. Metastasis in adenocarcinoma occurs more frequently than in squamous cell carcinoma, but most common in small cell carcinoma. Tumors at any site can metastasize to the distant mediastinum. Except for squamous cell carcinoma with maximum diameter less than 1.5 cm which are likely to be cured without lymph node dissection, other types of T(1) carcinoma of the lung need extended lymph node dissection.

Adult↗
PubMed2002

[Gene diagnosis and prognosis of mediastinal lymph node occult micrometastasis in non-small cell lung carcinoma].

OBJECTIVE: To investigate gene diagnosis of occult micrometastasis in the mediastinal lymph node in patients with non-small cell lung carcinoma (NSCLC) and to evaluate its prognostic significance. METHODS: With mRNA expression of mucoid1 (MUC1) gene examined by RT-PCR, 168 mediastinal lymph nodes taken from 37 pN(0) (negative lymph nodes) NSCLC patients (stage Ia approximately IIb) made up the experiment group. Thrity negative lymph nodes from 14 benign lesions and 30 positive lymph nodes from 15 NSCLC patients served as control. The survival difference between MUC1 mRNA-negative and MUC1 mRNA-positive groups was compared by the chi(2) test. RESULTS: UC1 mRNA was not identified in the negative-control group (specificity = 100%), but it was identified in 26 of 30 positive-control samples (sensitivity = 86.7%). MUC1 mRNA was identified in 16 (9.5%) of the experiment group from 12 patients whose TNM stage was up-regulated to stage IIIa. The 3-year survival rate (58.3%) of MUC1 mRNA positive group patients with occult micrometastasis in mediastinal lymph node was lower than the 88.0% of MUC1 mRNA negative group (P < 0.05). CONCLUSION: Occult micrometastasis in the mediastinal lymph node in NSCLC patients can be diagnosed by MUC1 mRNA expression through RT-PCR. Poor prognosis in some pN(0) NSCLC patients may be associated with nodal occult micrometastasis.

Adult↗
PubMed2002

[A study on the protective mechanism of yisheng injection against the anoxia-reoxygenation injury to endothelial cells].

OBJECTIVE: To explore the mechanism of ischemia reperfusion injury (IRI) and the protective effect of Yisheng injection on endothelial cells (ECs). METHODS: Human umbilical veins endothelial cell line ECV304 was cultured in RPMI medium 1640 without glucose under 100% N2 for one and a half hours, and then in RPMI medium 1640 with glucose under normal conditions for 5 hours to mimic ECs' IRI posttransplantaion. A pure nature medicine, Yisheng injection was added into the medium in experimental group. Intracellular calcium and mitochondrial were shown through flourescent staining. The activities of succinic dehydrogenase (SDH) and lactic dehydrogenase (LDH) were detected by cytochemical staining. The concentrations of superoxide dismutase (SOD), malonaldehyde (MDA) and nitrous oxide (NO) in culture medium were determined. RESULTS: After treatment with anoxia-reoxygenation, the ECs' morphologic changes were observed, and intracellular calcium concentration, LDH activity, MDA concentration became higher. Meanwhile, mitochondrial membrane potential, concentrations of SOD and NO were lower. Yisheng injection made these changes disappear or become less. CONCLUSION: Anoxia-reoxygenation induces lipid peroxidation, calcium superrcharge in ECs, and damage to mitochondrial function. Yisheng injection can reverse these changes, thus protecting the endothelial cells.

Cell Line↗
PubMed2002

[A method for rapid and early diagnosis of trisomy 21 using molecular techniques].

OBJECTIVE: Using molecular techniques, we typed 2 short tandem repeat (STR) loci on 21 chromosome to establish the method for rapid and accurate diagnosis of trisomy 21. METHODS: Genomic DNA samples from 50 individuals diagnosed previously by karyotype as trisomy 21 and 40 children with severe mental retardation (IQ < 50) suspected of trisomy 21 were analyzed for 2 short tandem repeat loci on 21 chromosome, D21S1435 and D21S2055. Typing was carried out after polymerase chain reaction (PCR) and silver staining. The trisomy was identified by the number of alleles: 3 alleles bands whose density is same, two alleles bands with one obvious higher density compared to the other and one allele band whose density is three times than the normal control. RESULTS: All of the complete trisomy 21 were detected by this method; the parental source was easily determined. CONCLUSION: This method for diagnosing trisomy 21 is rapid and accurate.

Chromosomes, Human, Pair 21↗
PubMed2002

[Study of autoantibodies against the G-protein-coupled beta 2- and alpha 1-adrenergic and AT1 receptors in patients with primary hypertension].

OBJECTIVE: To determine whether autoantibodies against the cardiac G-protein-coupled beta 2- and alpha 1-adrenergic and AT1 receptors are related to patients with primary hypertension. METHODS: Synthetic peptides corresponding to amino acid sequences of the second extracellular loops of the beta 2- and alpha 1-adrenergic and AT1 receptors were respectively used as antigens to screen sera from patients with hypertensive heart diseases (n = 50) as well as simple hypertension (n = 40) and healthy blood donors (n = 40) using ELISA test. RESULTS: The positive ratio of autoantibodies against beta 2 and alpha 1 and AT1 receptors in patients with hypertensive heart diseases were significantly higher than patients with simple hypertension and healthy donors. The geometric mean titers of autoantibodies against beta 2- and alpha 1-adrenergic and AT1 receptors had no difference between the patients with hypertensive heart diseases and the patients with simple hypertension, but the geometric mean titers of two groups were higher than healthy donors. In the patients with hypertensive heart diseases, 81.0% of the patients with autoantibodies against beta 2-adrenergic receptor had autoantibodies against alpha 1-adrenergic receptor and 76.2% had autoantibodies against AT1 receptors. The percent of the autoantibodies against three receptors in patients with hypertensive heart diseases were 52.4%. CONCLUSIONS: Autoantibodies against beta 2- and alpha 1-adrenergic and AT1 receptors play an important role in the pathophysiological changes of primary hypertension, and may participate myocardial and vessel remodeling.

Adult↗
PubMed2002

[Expression and purification of gene transfer vehicle mediated by epidermal growth factor receptor].

OBJECTIVE: To create a gene transfer vehicle for targeting gene therapy of cancer with epidermal growth factor receptor overexpressing. METHODS: Encoding sequences of the first domain of histone gene (H1) and EGF C-loop (EGFc) were obtained by PCR amplification. These two DNA fragments were ligated by EcoR I site, and cloned and sequenced. E. coli expression vector of the fusion gene was then constructed. The fusion protein H1EGFc was purified by specific band isolation from SDS-PAGE. RESULTS: The molecular weight of purified protein was consistent with the designed request. Its purity reached 94.02%. CONCLUSION: A fusion protein H1EGFc was expressed and purified.

Amino Acid Sequence↗
PubMed2002

[Study on the function of HSD-3.8 gene encoding a testis-specific protein with yeast two-hybrid system].

OBJECTIVE: To explore the protein factors that could interact with the testis-specific protein encoded by HSD-3.8 gene (GenBank Accession Number AF311312) related with female fertilization. METHODS: Yeast two-hybrid system was used to screen the human ovary MATCHMAKER cDNA library with constructed "bait plasmid" containing the 0.7 kb fragment (HSD-0.7) of HSD-3.8. The interaction with the positive fragments using a series of truncated bait plasmids was investigated. RESULTS: One positive gene fragment was obtained, which coded for 144 amino acids of the C-terminus of human G protein beta subunit 1. Truncated bait plasmids couldn't interact with the fish protein fragment in yeast. CONCLUSIONS: The protein encoded by HSD-3.8 gene may function through G protein signal transduction pathway and the interaction depends on the integration of the bait protein.

Adenosine Triphosphate↗