Biomedical subjects

J Tian

Publications and source records attributed to J Tian.

At least 91 records · Page 5Linked to original sources

PubMed1999

Detection of p53 gene mutations: analysis by single-strand conformation polymorphism and Cleavase fragment length polymorphism.

We have generated a collection of clones containing single point mutations within the exon 5-9 hot spot regions of the p53 gene by using polymerase chain reaction (PCR) to amplify select regions of the gene from characterized cell lines. These clones were then used to address the sensitivity of mutation detection using slab-gel single-strand conformation polymorphism (SSCP) and Cleavase fragment length polymorphism (CFLP) assay systems. Both methods exhibited high sensitivities for the detection of mutations in cloned p53 mutations in this study: 97% for CFLP and 94% for SSCP. In addition to resulting in higher sensitivity of mutation detection, CFLP has the capability to analyze longer fragments. In this study, CFLP identified five intronic mutations which were not investigated in the exon-specific SSCP assay. These results agree with those found elsewhere and demonstrate that CFLP scanning can have practical advantages when used for the identification of sequence alterations within the p53 gene.

Genes, p53↗

PubMed1999

Antigen-based immunotherapy for autoimmune disease: from animal models to humans?

Insights into tolerance and autoimmune processes have led to novel immunotherapeutics for inhibiting autoimmune disease in animal models. However, recent studies question the immune basis of some of these therapeutic strategies and raise concerns about their efficacy and safety. Here, we discuss the feasibility of extending the success of antigen-based immunotherapeutics for T-cell-mediated autoimmune diseases from animal models to humans.

Animals↗

PubMed1999

New human hepatocellular carcinoma (HCC) cell line with highly metastatic potential (MHCC97) and its expressions of the factors associated with metastasis.

A new human hepatocellular carcinoma (HCC) cell line with a highly metastatic potential was established from subcutaneous xenograft of a metastatic model of human HCC in nude mice (LCI-D20) by means of alternating cell culture in vitro and growth in nude mice. The line, designated MHCC97, has been cultivated for 18 months and subcultured for more than 90 passages. The line was showed to be of human origin by karyotype analysis. The cells were either grown as compact colonies (in clusters) or as a monolayered sheet with about 31 h of population-doubling time, exhibited typical malignant epithelial in morphology and were positive for alpha-fetoprotein (AFP). Flow cytometric analysis of the cell DNA content showed an aneuploid pattern, and its index was 1.5 as compared to that of normal human peripheral blood lymphocytes. Karyotypic analyses of G- and C-banding techniques revealed that all cells presented chromosome abnormalities in number and structure. The number of cell line MHCC97 chromosome ranged from 59 to 65 with a modal number of 60 and 61. At least two common chromosome markers, i(1q) and der(4)t(4;?)(4pter-->q35::?), were present in all cells, and deletion of Y chromosome also occurred in all cells. The subcutaneous and intrahepatic xenografts were formed and metastatic lesions in lungs were found after the cells were inoculated into nude mice. The rate of metastasis to lungs was 100% using orthotopic inoculation. Reverse transcription polymerase chain reaction products revealed positive expressions of integrin alpha5 and beta1, urokinase type plasminogen activator receptor (uPAR), vascular endothelial growth factor and nm23-H1 mRNAs of cell line MHCC97. Immunostaining of c-Met, uPAR showed strongly positive in both subcutaneous xenografts and lung metastatic lesions; while positive in xenografts and negative in metastatic lesions for integrin alpha5, beta1. E-cadherin and P53 was not expressed either in xenograft or in the metastatic lesions. PCR products of HBsAg and HBxAg were both positive. The cell line MHCC97 still retained some characteristic features of original tumour. Establishment of cell line MHCC97 should be beneficial to the studies of HCC metastatic mechanisms.

Adult↗

PubMed1999

Stability, activity and flexibility in alpha-lactalbumin.

alpha-Lactalbumins and the type-c lysozymes are homologues with similar folds that differ in function and stability. To determine if the lower stability of alpha-lactalbumin results from specific substitutions required for its adaptation to a new function, the effects of lysozyme-based and other substitutions on thermal stability were determined. Unblocking the upper cleft in alpha-lactalbumin by replacing Tyr103 with Ala, perturbs stability and structure but Pro, which also generates an open cleft, is compatible with normal structure and activity. These effects appear to reflect alternative enthalpic and entropic forms of structural stabilization by Tyr and Pro. Of 23 mutations, only three, which involve substitutions for residues in flexible substructures adjacent to the functional site, increase stability. Two are lysozyme-based substitutions for Leu110, a component of a region with alternative helix and loop conformations, and one is Asn for Lys114, a residue whose microenvironment changes when alpha-lactalbumin interacts with its target enzyme. While all substitutions for Leu110 perturb activity, a Lys114 to Asn mutation increases T(m) by more than 10 degrees C and reduces activity, but two other destabilizing substitutions do not affect activity. It is proposed that increased stability and reduced activity in Lys114Asn result from reduced flexibility in the functional site of alpha-lactalbumin.

Amino Acid Sequence↗

PubMed1999

[Transcranial approach to the orbit: a microanatomical study].

OBJECTIVE: To provide detailed knowledge of microanatomy and parameters for transcranial approach to the orbit. METHOD: Three intraorbital approaches were studied by dissecting and measuring 20 adult cadaveric heads under x5 to 25 magnification. RESULTS: The medical approach was directed through the space between the superior oblique and the levator palpebrae superior muscles, which was selected for lesions located in the medial part of the orbital apex. The central approch was directed through the space between the levator palpebrae superior and the superior rectus muscles. There were two variants of the central approach, the choice of which depends on whether the frontal nerve was retracted medially or laterally. The approach was selected for lesions located in the midportion of the intraorbital segment of the optic nerve. The lateral approach was directed through the space between the superior and the lateral rectus muscle. There were two variants of the lateral approach, the choice of which was determined by whether the superior ophthalmic vein is retracted medially or laterally. This approach was selected for lesions located in the superior, inferior or lateral part of the orbital apex as well as the superior orbital fissure. CONCLUSION: This research provides a microanatomical foundation for avioding the important nerves and vessels damage in transcranial to orbital surgery.

Adult↗

PubMed1999

[Expressions of the metastasis-associated factors of a new human hepatocellular carcinoma cell line with highly metastatic potential].

OBJECTIVE: To explore the expressions of some metastasis-related factors in a new human hepatocellular carcinoma cell line with a highly metastatic potential by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. METHODS: A human hepatocellular carcinoma (HCC) cell line (MHCC97) was established derived from subcutaneous xenograft of a metastatic model of human HCC in nude mice (LCI-D20) by means of alternating cell culture in vitro and grown in nude mice. RT-PCR and immunohistochemistry were performed on this line and its intrahepatic xenografts and metastatic lesions to explore the expressions of metastasis-related factors. RESULTS: The tumorigenicity and metastatic rate to lungs of MHCC97 cell line was 100% by orthotopic inoculation. RT-PCR products for integrin alpha 5 and beta 1, uPAR, VEGF and nm23-H1 mRNA from MHCC97 cell line were positive. Immunostaining showed strongly positive for c-Met, uPAR in both of xenografts and lung metastatic lesions, and also positive in xenografts, but negative in lung metastatic lesions for integrin alpha 5 and beta 1. E-cadherin was not expressed either in xenografts or in the metastatic lesions. The PCR productions for HBsAg and HBxAg were positive, and negative for HBcAg. CONCLUSIONS: MHCC97 cell line has a ability to express some metastasis-associated factors. DNA for virus hepatitis B may be integrated into the genome of MHCC97 cells.

Animals↗

PubMed1999

Surgical treatment of hepatocellular carcinoma and related basic research with special reference to recurrence and metastasis.

OBJECTIVE: To summarize the progress of surgical treatment of hepatocellular carcinoma (HCC) and related basic research at the Liver Cancer Institute of Shanghai Medical University in the recent years, with special reference to recurrence and metastasis. METHODS: Published and unpublished update clinical and experimental data in the above-mentioned areas are summarized. RESULTS: Surgical resection has played an important role in improving prognosis of HCC, the 5-year survival were 63.4% for small HCC resection (n = 806), 39.6% for large HCC resection (n = 1061), 64.7% for cytoreduction (using hepatic artery cannulation and ligation) and sequential resection of initially unresectable HCC (n = 93), 56.0% for cytoreduction using transcatheter arterial chemoembolization (TACE) and followed by resection (n = 65), and 22.4% for hepatic resection with removal of tumor thrombi in portal vein (n = 103). Unfortunately, the 5-year recurrent rate after curative resection of HCC was up to 61.5%, which was mainly a result of intrahepatic "metastasis" and multicentric origin of HCC. Clinically, re-resection of subclinical recurrence yielded 56% of 5-year survival (n = 202); prevention of recurrence by transcatheter arterial chemoembolization (TACE) + Interferon, or LAK/IL-2 therapy have decreased 3-year recurrent rate from 33% to 11%-18%. In experimental aspect, metastatic human HCC model in nude mice (LCI-D20) and HCC cell line with metastatic potential (MHCC97) have been established; studies on HCC invasiveness in the molecular level revealed similar results that reported in other solid cancers, and small HCC showed slightly better biological characteristics as compared with large HCC; microvessel density (MVD) that reflecting angiogenesis adversely correlated with 5-year survival of small HCC; experimental interventions using antisense H-ras, bispecific antibody, BB94, as well as anti-angiogenic agents (TNP470, suramin, CAI, heparin, antisense VEGF, etc.) have been demonstrated to inhibit tumor growth and lung metastasis in nude mice model. CONCLUSIONS: Recurrence and metastasis are the major obstacle to further improve prognosis of HCC, studies should be conducted both in clinical and experimental aspects, "HCC invasiveness" will be the major target to be studied, particularly in the molecular level, and anti-angiogenesis will be one of the important approach.

Angiogenesis Inhibitors↗

PubMed1999

[Development of partially sintered alumina block for dental CAD/CAM and mechanical properties testing].

OBJECTIVE: It is a new way to fabricate all ceramic crowns by combining dental CAD/CAM with glass infiltration technology. METHODS: A partially alumina sintered block made of a high purity, fine alumina powder was shaped by isostastic pressure and sintered at 1,400 degrees C. Its mechanical properties were tested and microstructure was observed by SEM. RESULTS: The Vicker's hardness, three-point bending strength, fracture toughness of partially sintered alumina block were 1.65 MPa, 210 MPa, 1.90 MPam1/2 respectively. Micrographs of SEM indicated that partially sintered alumina contained the structure of continuous three-dimensional open pores through the neck growth and surface diffusion of the interparticles. CONCLUSION: The partially sintered alumina block that developed in this way may be used to mill for CAD/CAM and fabricate the shrinkage-free all ceramic crown.

Aluminum Oxide↗

PubMed1999

[Application of X-ray diffraction to the analysis of traditional Chinese medicine].

OBJECTIVE: To approach the application of powder Xray diffraction in analysis of traditional Chinese medicine(TCM). METHOD: Studying the references published in recent years and making a summary on the subject of application of Xray in the pharmaceutical analysis of TCM. RESULT: This method is effective in identifying and analyzing TCM. CONCLUSION: This technique may have broad prospects for pharmaceutical analysis.

Drug Contamination↗

PubMed1999

[Infrared spectral identification of rhizoma Corydalis and rhizoma Corydalis repentis].

OBJECTIVE: To study the IR spectra of Rhizoma Corydalis and Rhizoma Corydalis Repentis. METHOD: The petroleum ether, ethyl ether and water extracts obtained by the same isolating procedure from Rhizoma Corydalis and Rhizoma Corydalis Repentis were determined by IR spectrophotometry. RESULTS: The IR spectral evidences of the two samples showed distinct characteristics and good repeatability. CONCLUSION: The IR spectral evidences can be used to differentiate Rhizoma Corydalis and Rhizoma Corydalis Repentis.

Corydalis↗

PubMed1999

[Effects of alumina particle-size on mechanical properties of alumina-glass composite].

OBJECTIVE: To study the effects of alumina particle-size on mechanical properties of alumina-glass composite. METHODS: Alumina compacts were prepared by isostatic press method and sintered at 1400 degrees C for 2 hours with two various particle-size alumina. Alumina-glass composite was made by infiltrating partially sintered porous alumina with glass at 1200 degrees C for 4 hours. RESULTS: The strength and fracture toughness of nanometre alumina-glass composite were 358.2 MPa, 2.38 MPam1/2 respectively. The strength and fracture toughness of micrometer alumina-glass composite were 432.2 MPa, 5.12 MPam1/2 respectively. Image analysis of SEM micrograph showed that porous rate was about 11.5% in the nanometer alumina-glass composite, 1.2% in the micrometer alumina-glass composite, and there was more glass composition in the nanometer alumina-glass composite than that in the micrometer alumina-glass composite. CONCLUSION: The alumina volume percentage and porous rate play an important role in the strength and fracture toughness of alumina-glass composite.

Aluminum Oxide↗

PubMed1999

[Two-dimensional finite element analysis for morphology of craniofacial hard tissue of people with anterior crossbite at early permanent dentition].

OBJECTIVE: To analyze the morphology of craniofacial hard tissue of people with anterior crossbite at early at early permanent dentition. METHODS: The craniofacial morphology of hard tissue of 80 cases anterior crossbite of the early permanent dentition was analyzed by a special computer software system for finite element analysis of two-dimensional cranio-facial structure. RESULTS: The size change of each element was smaller than shape change in cross-bite group, which suggested that the shape change was the main element change; The posterior cranial base was found abnormal in both male and female groups, with counterclockwise rotation occurring at posterior cranial base to some extent; The upper part of face and the maxillary suffered underdevelopment in both male and female groups; The most outstanding change in size and shape occurred at anterior and superior part of mental, with each component of counterclockwise rotation to varying degree. CONCLUSION: Abnormality that occurs in craniofacial hard tissue of people with anterior crossbite at early permanent dentition period is highlighted by abnormal skeletal shape change and rotation, and may be one of the fundamental factors causing crossbite.

Adolescent↗

PubMed1999

[Mechanism study of muscle injury from high tension (I)--The biomechanical effect of training on muscle injury from downhill running in rats].

In this experiment, we tested the biomechanical characteristics of rat's fast and slow skeletal injury from downhill running at different times. The result indicates that the mechanical properties of fast and slow skeletal muscle, including maximum tensile strength, maximum strain, elasticity and energy absorption, gradually stregthen with extended time (not more than 48 hours) after eccentric exercise-induced injury. On the other hand, the maximum strain of slow muscle is higher than that of fast muscle.

Animals↗

PubMed1999

[Prevention of keloids of the earlobes].

OBJECTIVE: To investigate the causing of keloids of the earlobes. METHOD: We have treated 41 keloides of earlobes in 28 cases, and analyzed the factors. RESULT: It has been found that infections, inappropriate supporter, allergy to nickel and gold, local delayed allergy are the chief factors to form keloides of the earlobes. CONCLUSION: Some measures to prevent those cousing mentioned above have been proposed.

Adolescent↗

PubMed1999

[Bone mineral analysis of whole body in 292 normal subjects assessed by dual X-ray absorptiometry].

OBJECTIVE: To understand whole body bone mineral changes in normal subjects. METHODS: Bone mineral was measured by dual X-ray absorptiometry (DXA) in 292 normal subjects aged 10-79, including 152 females and 140 males. They were divided into age-groups by decade. RESULTS: In males, peak value ages of total bone mineral content(TBMC), total bone mineral density(TBMD), anteroposterior spine BMD(L2-4 BMD) were in the 30-39, 20-39, 20-29 age-groups respectively. In females, they were all in the 30-39 age-group. Peak values of TBMC, TBMD, L2-4BMD were higher in males than those in females. Loss of bone mineral for females was more pronounced than that for males. There was a tendency of increased BMD among the 70-79 age-group for males. Loss of L2-4 BMD was more pronounced than TBMD. CONCLUSIONS: This study provides the normal bone mineral data of whole body for males and females, and the characteristic of changes.

Absorptiometry, Photon↗

PubMed1999

Comparison of bone mass in forearm, lumbar vertebra and hip by single and/or dual energy X-ray absorptiometry.

OBJECTIVE: Bone mineral density (BMD) was measured in normal Chinese women with single X-ray absorptiometry (SXA) and dual energy X-ray absorptiometry (DEXA). These two methods were compared to evaluate the sensitivity in reflecting bone loss. METHODS: Measurements were performed in 300 women aged 20 to approximately 79 (5 for each age). The 8mm distal, 1/4 distal, ultra distal site of the nondominant forearm were measured with SXA; the AP spine (L2-4), right femoral neck (Neck), Ward's triangle (Ward) and trochantor (Troch) were measured with DEXA. Ten women had 5 repeated measurements to evaluate the reproducibility of the equipments. RESULTS: The BMD peak for Neck and Ward was found between age 20 to approximately 29, for ultra distal and L2-4 at age 30 to approximately 39, for 8mm distal, 1/4 distal and Troch at age 40 to approximately 49. After reaching the peak values, BMD at all sites decreased with increasing age. The highest rate of yearly loss of BMD was at 8mm distal. Results of measurement showed significant correlation between SXA and DEXA. Comparing with premenopausal women, the bone loss rate in postmenopausal women was faster and highest up to 11 to approximately 15 years and the highest rate was at the Ward. CONCLUSION: The present study gives the normal values of BMD at seven sites for normal Chinese women. The ages of BMD peak were different at seven sites. The yearly loss of BMD was highest at 8mm distal, it seemed to be the sensitive region for bone loss with age. The postmenopausal women had highly significantly loss bone mass than the premenopausal women. Comparing with premenopause, postmenopause BMD for Ward's triangle with DEXA seemed to be most sensitive to the effect of menopause.

Absorptiometry, Photon↗

PubMed1998

Attenuation of inducible Th2 immunity with autoimmune disease progression.

Autoantigen-based immunotherapeutics have been shown to activate regulatory responses capable of inhibiting T cell-mediated autoimmune disease in animal models. However, their efficacy generally declines, as treatment occurs later in the disease process, and their mechanism of action is a matter of intense debate. Here, we report that the early administration of beta cell autoantigens (betaCAAs) to nonobese diabetic (NOD) mice broadly diverts the natural development of potentially pathogenic Thl-biased autoimmune responses toward the Th2 phenotype through Th2 spreading. With disease progression, there was a steady decline in the ability of betaCAA treatment to promote Th2-type cellular and humoral autoimmunity. Late in the disease process, some betaCAAs were still able to induce Th2 responses and Th2 spreading (although to a much lesser extent), while other autoantigens were not. This attenuation of inducible Th2 immunity with disease progression is likely to reflect a reduction in the availability of uncommitted autoantigen-reactive precursor T cells. These findings suggest that there are inherent differences in the frequency of betaCAA-reactive T cells and that, in advanced stages of autoimmune disease, regulatory responses may be best elicited with target tissue Ags against which large uncommitted T cell pools are still available. Since individuals presenting the first signs of autoimmune disease are likely to already have an advanced disease process, these findings may be useful for the rational design of Ag-based immunotherapeutics.

Animals↗

PubMed1998

Interaction of the adenovirus 14.7-kDa protein with FLICE inhibits Fas ligand-induced apoptosis.

Adenovirus type 5 encodes a 14.7-kDa protein that protects infected cells from tumor necrosis factor-induced cytolysis by an unknown mechanism. In this report, we demonstrate that infection of cells with an adenovirus vector expressing Fas ligand induced rapid apoptosis that was blocked by coinfection with a virus expressing 14. 7K. Moreover, AdFasL/G infection resulted in the rapid activation of DEVD-specific caspases, and caspase activation was blocked by coinfection with Ad14.7/G. Cell death induced by the overexpression of Fas ligand, Fas-associated death domain-containing protein (FADD)/MORT1, or FADD-like interleukin-1beta-converting enzyme (FLICE)/caspase-8 in a virus-free system was efficiently blocked by 14.7K expression. Moreover, we demonstrate that 14.7K interacts with FLICE. These results support the idea that FLICE is a cellular target for the 14.7-kDa protein.

Adaptor Proteins, Signal Transducing↗