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Biomedical subjects

S Pan

Publications and source records attributed to S Pan.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Changes of leukocyte rheologic characteristics and cell adhesion molecules in patients with multiple organ failure after severe trauma].

OBJECTIVE: To explore the changes of leukocyte rheologic characteristics and of cell adhesion molecule in patients with multiple organ failure (MOF) after severe trauma. METHODS: By using the erythrocyte deformability apparatus, platelet and thrombus adhesion dual-purpose apparatus and enzyme-linked immunosorbent assay (ELISA), We measured the leukocyte deformability (LD), leukocyte adhesion function (LAF), leukocyte CD18 expression, soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule (sVCAM-1) concentration in 36 MOF patients, 31 trauma patients, and 35 to be controls. RESULTS: The leukocyte filtration index (LFI), leukocyte adhesion rate (LAR), leukocyte CD18 expression, and sICAM-1 and sVCAM-1 concentration were significantly higher in MOF patients than in controls and trauma patients (F = 68.45 - 116.20, q = 12.161 - 21.374, P < 0.00), and the changes of these indicators in MOF deaths were more obvious than those in MOF survivors (t = 6.920 - 11. 665, P < 0.00). The LFI and LAR in MOF patients were positively related to leukocyte CD18 expression, sICAM-1, and sVCAM-1 concentration (r = 0.691 - 0.844, P < 0.001); LFI was positively related to LAR (r = 0.711, P < 0.001). CONCLUSION: The abnormalities of leukocyte rheologic characteristics and CAMs might be closely related to the occurrence of MOF and the severity of pathologic changes.

Adult↗
PubMed2000

[Effect of raw radish on pharmacological action of ginseng].

Ginseng decoction can increase the memory-improvement, weary-resistance, antihypoxia, sedation in mice, and increase the weight of spleen and accessory sexual gland, but reduce the weight of thymus. Raw radish can decrease these pharmacological effects in varying degrees, except the sedation.

Animals↗
PubMed1999

The regulation of caveolin expression and localization by serum and heparin in vascular smooth muscle cells.

Caveolae have been implicated in growth factor receptor and G-protein coupled receptor signaling in vascular cells. It has been postulated that caveolin, the structural protein of caveolae, may act as a general tyrosine kinase inhibitor by binding and inhibiting signaling molecules involved in the activation of the MAP kinase proliferation cascade. Using an in vitro model of VSMC proliferation, we found that serum stimulation caused a dose dependent decrease in both caveolin-1 and caveolin-2 protein levels in human coronary artery smooth muscle cells. Heparin, an inhibitor of VSMC proliferation, inhibited the serum-induced loss of caveolin-1 and caveolin-2. In addition, heparin caused an increase in both caveolin-1 and caveolin-2 localization to caveolae-enriched sucrose gradient membrane fractions when compared to serum alone. Taken together, caveolin may play an important role in the regulation of VSMC proliferation and heparin and serum have opposing effects on caveolin expression and localization in VSMC.

Caveolin 1↗
PubMed1999

[Influence of aging and sex on chromosome 21 segregation in human lymphocytes]

OBJECTIVE: To determine the influence of aging and sex on the segregation of chromosome 21. METHODS: Lymphocytes were obtained from healthy donors of different ages, both sexes, and were treated with cytochalasin B. Binucleated cells were hybridized with chromosome 21 specific probe, and simultaneously, chromosome 21 loss and non-disjunction were detected. RESULTS: The coefficients of correlation between age and binucleated cells containing 4, 2 and 6 signals were -0.35(P<0.01), 0.18 and 0.38(P<0.01) respectively. The coefficients of correlation between age and nondisjunction of chromosome 21 and micronuclei were 0.56(P<0.01) and 0.70(P<0.01) respectively. CONCLUSION: There is a significant increase with age in the number of micronuclei and missegregation. Nondisjunction of chromosome 21 is much more frequent than loss in vivo and in vitro. No significant difference in nondisjunctioin between male and female was noted. Age effect is more significant in female than in male.

Journal Article↗
PubMed1999

Ferrocene-conjugated m-phenylenediamine conducting polymer-incorporated peroxidase biosensors.

The development and characteristics of a reagentless amperometric biosensor employing horseradish peroxidase incorporated in an electrochemically deposited ferrocene-modified phenylenediamine film on a glassy carbon electrode is reported. The horseradish peroxidase/poly(m-aminoanilinomethylferrocene)- modified glassy carbon electrode reagentless biosensor measured hydrogen peroxide and other organic peroxides in both aqueous and organic medium by reduction at a low applied potential of -0.05 V (vs Ag/AgCl) without interference from molecular oxygen. When modified with glucose oxidase, the new bienzyme electrode measured glucose sensitively and selectively, demonstrating the suitability of the above peroxide biosensor for other oxidoreductase enzyme-based biosensors.

Biosensing Techniques↗
PubMed1999

Complementation between HLA-DR4 (DRB1*0401) and specific H2-A molecule in transgenic mice leads to collagen-induced arthritis.

We generated transgenic mice with DRB1*0401 gene with mutation in the beta2 domain (aa 110 and 139) for better interaction with mCD4. The DR4 transgene was introduced into H2-Aq (B10RQB3) and H2-Af (B10RFB3) to examine the role of DR4 in collagen arthritis. The HLA-DR molecules in these mice were found to be functional on the basis of their positive/negative selection of the Vbeta T cell repertoire. H2-Aq mice are resistant to porcine CII-induced arthritis. The RQB3/DR4 mice (H2Aq/DR4) developed severe collagen induced arthritis (CIA) when immunized with Porcine type II collagen while the negative littermates were resistant. RQB3.DR4 mice were also highly susceptible to CIA induced by Human CII while negative littermates got only mild disease. However, RFB3/DR4 mice (H2Af/ DR4) did not get CIA with any type II collagen. Therefore, the DR4 gene in the context of H2-Aq predisposes to severe arthritis but not in the context of H2-Af. Antibodies to renatured cyanogen bromide (CB) cleaved fragments of PII in RQB3/DR4 mice and negative littermates suggest that the presence of DR4 does not result in any differences in specificity of antibody response to CB fragments. These results indicate that a specific gene complementation occurring between DR4 and H2.Aq but not DR4 and H2Af promotes the induction of arthritis with PII and HII in these mice. A similar interaction may be involved between DR and DQ molecules in human RA.

Animals↗
PubMed1999

Specific interactions with TBP and TFIIB in vitro suggest that 14-3-3 proteins may participate in the regulation of transcription when part of a DNA binding complex.

The 14-3-3 family of multifunctional proteins is highly conserved among animals, plants, and yeast. Several studies have shown that these proteins are associated with a G-box DNA binding complex and are present in the nucleus in several plant and animal species. In this study, 14-3-3 proteins are shown to bind the TATA box binding protein (TBP), transcription factor IIB (TFIIB), and the human TBP-associated factor hTAF(II)32 in vitro but not hTAF(II)55. The interactions with TBP and TFIIB were highly specific, requiring amino acid residues in the box 1 domain of the 14-3-3 protein. These interactions do not require formation of the 14-3-3 dimer and are not dependent on known 14-3-3 recognition motifs containing phosphoserine. The 14-3-3-TFIIB interaction appears to occur within the same domain of TFIIB that binds the human herpes simplex virus transcriptional activator VP16, because VP16 and 14-3-3 were able to compete for interaction with TFIIB in vitro. In a plant transient expression system, 14-3-3 was able to activate GAL4-dependent beta-glucuronidase reporter gene expression at low levels when translationally fused with the GAL4 DNA binding domain. The in vitro binding with general transcription factors TBP and TFIIB together with its nuclear location provide evidence supporting a role for 14-3-3 proteins as transcriptional activators or coactivators when part of a DNA binding complex.

14-3-3 Proteins↗
PubMed1999

[Influence of aging and sex on chromosome 21 segregation in human lymphocytes].

OBJECTIVE: To determine the influence of aging and sex on the segregation of chromosome 21. METHODS: Lymphocytes were obtained from healthy donors of different ages, both sexes, and were treated with cytochalasin B. Binucleated cells were hybridized with chromosome 21 specific probe, and simultaneously, chromosome 21 loss and non-disjunction were detected. RESULTS: The coefficients of correlation between age and binucleated cells containing 4, 2 and 6 signals were -0.35(P<0.01), 0.18 and 0.38(P<0.01) respectively. The coefficients of correlation between age and nondisjunction of chromosome 21 and micronuclei were 0.56(P<0.01) and 0.70(P<0.01) respectively. CONCLUSION: There is a significant increase with age in the number of micronuclei and missegregation. Nondisjunction of chromosome 21 is much more frequent than loss in vivo and in vitro. No significant difference in nondisjunctioin between male and female was noted. Age effect is more significant in female than in male.

Adult↗
PubMed1999

Three-dimensional finite element analysis and comparison of stress distribution in overdentures supported with bar attachments and telescopic crowns.

OBJECTIVE: To determine which one of the overdenture (OD) retainers was more beneficial to the abutments--the bar or the telescopic crown--and if a tooth could be used as an OD abutment when the supporting bone decreased to half of the root. MATERIALS AND METHODS: The three-dimensional finite element method was used to investigate the stress distribution in a mandible with an overdenture supported by the roots of two canines. The two teeth were either connected with a bar attachment or restored with telescopic crowns, and were then restored with a complete overdenture. For each type of superstructure, the influence of bone height around the roots (no alveolar resorption and resorption to half of the root length) was analyzed under three loading conditions. RESULTS: The most extreme stress values were located at the alveolar ridge crest of the bone around the root of the abutment. In the case of anterior loading, the largest compressive stress (LCS) in telescopic crown overdenture (TOD) was lower. When loaded posteriorly there was no obvious difference between bar attachment overdenture (BOD) and TOD. At the alveolar ridge crest around the root of the abutment, the stress value in the model with decreased bone level was higher than in the model with normal bone level, but the range was not significant. CONCLUSION: 1. In terms of stress in the alveolar bone, complete overdenture over telescopic crowns is more convenient than over bar attachments. 2. Stress increases as the height of the bone around the roots decreases, but the increment is less than 30%. It is important for an abutment with bone resorption to perform root amputation to obtain an acceptable crown/root ratio.

Alveolar Bone Loss↗
PubMed1999

MRI evaluation of bone marrow of normal lumbar vertebra in the Chinese: normal patterns and preliminary quantitative study.

OBJECTIVES: To establish the normal patterns of lumbar vertebral marrow in normal Chinese, to determine its normal value of relaxation times (T1 and T2), and to investigate the relationship between relaxation time and age or sex. METHODS: 320 of 1000 cases (sampled randomly) received MR imaging. According to the MRI findings of sagittal T1WI, marrow patterns were established. 268 cases were studied quantitatively (T1 and T2 measurements). RESULTS: The normal bone marrow patterns of lumbar vertebra were divided into four main patterns (six subgroups). The normal values of relaxation times (T1 and T2) were measured. T1 or T2 value decreased with aging. No significant difference in T1 value between two sexes (< 40 years old: u = 0.4307, P > 0.50; > or = 40 years old: u = 0.554, P > 0.05). No significant difference was seen in T2 value between two sexes before 40 years old (u = 1.3628, P > 0.10), but significant difference after 40 years old (u = 2.1498, P < 0.05). CONCLUSIONS: To establish the normal patterns of lumbar vertebral marrow and determine its normal values of relaxation times have important clinical value in the diagnosis of bone marrow diseases.

Adolescent↗
PubMed1999

Distribution of human lens crystallins and their sulphydryl contents of different age in two-dimension electrophoresis.

PURPOSE: To analyze water-soluble (WS) human lens proteins of fetus, adult and age-related cataract by two-dimensional IEF/SDS-PAGE electrophoresis. METHODS: DACM [N-(7-Dimethylamino-4-methyl-3-coumarinyl) maleimide] was used to determine the lens proteins sulphydryl (SH) content. RESULT: Protein SH contents in WS lens proteins have no significant difference among fetus, adult and age-related cataract lens. This is different from the relative published results obtained in lens proteins of animal cataract model using similar SH detecting methods. CONCLUSIONS: IEF/SDS-PAGE electrophoresis demonstrated that there were much more fragmentation of crystallins during lens development and cataractogenic process. It is suggested that this phenomenon is likely to be due to further conformational changes in the fragmented cyrstallins during aging and cataractogenic process.

Adult↗
PubMed1999

Effect of liposome-encapsulated total alkaloid of harmaline on rabbit lens epithelial cells: experimental study on the prevention of posterior capsule opacification.

PURPOSE: To investigate whether liposome encapsulated total alkaloid of Harmaline (TAH) as a therapeutic agent is beneficial to prevention of posterior capsular opacification (PCO). METHODS: Liposome-encapsulated TAH was prepared by modified freeze-thawing method. 0.1 ml of liposome-encapsulated TAH (0.2 mg/ml) was injected into the capsular bag during extracapsular lens extraction (ECLE) of each eye in total 10 rabbit eyes. Blank liposome or balance salt solution (BSS) was used as control. Slit-lamp examination and histopathological examination was used to evaluated capsule opacification. Intraocular pressure (IOP), density and morphology of corneal endothelia cells, the amplitude and latency of b wave of ERG were measured. RESULTS: The inflammatory response was mild both in TAH treated and the control group. PCO formation occurred in the control group 2 weeks postoperatively, but the posterior capsule was clear in TAH treated eyes. 4 weeks and 8 weeks after operation, PCO occurred both in TAH treated and control eyes. However, it was milder in the TAH treated eyes. IOP remained at the normal level in all eyes. There was no difference in the density of corneal endothelial cells, and the amplitude and latency of b wave of ERG between TAH treated and control eyes. Histopathological study revealed that lens epithelial proliferation occurred 4 weeks and the Soemmerings ring developed 8 weeks postoperatively in the control eyes. However, only mild vacuolization and pkynotic changes of lens epithelial cells were found in TAH treated eyes. Transmmission electronic microscopy demonstrated that there were mild cytoplasm vacuolization and mitochondria swelling of lens epithelial cells in TAH treated eyes. CONCLUSION: The results suggest that liposome encapsulated TAH can inhibit metaplasia and proliferation of lens epithelial cells in the rabbit eye without obvious toxicity to the eye tissue. It may be used as a potential agent to prevent the development of PCO.

Alkaloids↗
PubMed1998

[Detection of Hep-2 and hepatoma cell line chromosomal aberration by using fluorescence in situ hybridization].

OBJECTIVE: To study the chromosomal aberration of hepatoma cell line (1172) and laryngocarcinoma cell line (Hep-2). METHODS: Fluorescence in situ hybridization (FISH) was used with nine chromosomal special libraries. RESULTS: The abnormal signals indicated that very complicated aberrations existed in the two cell lines. This suggested that the aberrations also existed in other chromosomes not yet studied. In 1172, the major type was structure aberration, but in Hep-2, numerical abnormality was shown in almost all chromosomes studied. CONCLUSION: Compared with traditional cytological methods, this technique has the advantages of being quicker and more accurate and sensitive.

Carcinoma↗
PubMed1998

HLA-DR4 (DRB1*0401) transgenic mice expressing an altered CD4-binding site: specificity and magnitude of DR4-restricted T cell response.

Optimum function of HLA-DR molecules in transgenic mice requires efficient interaction between the class II molecules on APCs and CD4 on T cells. Residues 110 and 139 of the second domain of class II molecules are considered to be critical for recognition of CD4. We generated an HLA-DR4beta(NT) transgene construct in which positions 110 and 139 were altered to resemble endogenous mouse H2 Abeta molecules. This construct was introduced into (B10 x SWR) embryos, and DR4beta(NT) transgenic mice were produced. The transgene was transferred into B10.RFB3 (Ebeta0 EalphaP) mice. The transgene-encoded DR4beta molecules paired with endogenous Ealpha chains to form stable DR4beta/Ealpha dimers expressed on the cell surface. The hybrid dimers showed similar Ag-binding specificity to HLA-DR4 molecules and positively selected CD4+ T cells in vivo. Immunization of HLA-DR4beta(NT) transgenic mice with DR4-restricted peptides induced T cell proliferation in vitro. While the purified T cells from DR4beta(NT) transgenic mice responded strongly to the HA(307-319) presented by M12C3 transfectants expressing altered DR4beta/Ealpha heterodimers, the response to the same peptides presented by transfectants expressing wild-type DR4beta/Ealpha molecules was substantially reduced. Taken together, these data confirmed in vitro studies on the importance of these residues in CD4-MHC class II interaction. The altered HLA-DR4beta transgenic mice were able to overcome the species barrier and generate efficient HLA-DR4-restricted CD4-specific immune responses. Thus, residues 110 and 139 were critical for the interaction of class II with CD4 T cells during thymic selection as well as peripheral immune responses.

Animals↗
PubMed1998

The EWS/ATF1 fusion protein contains a dispersed activation domain that functions directly.

Naturally occurring chromosomal fusion of the Ewings Sarcoma Oncogene (EWS) to distinct cellular transcription factors, produces aberrant transcriptional activators that function as dominant oncogenes. In Malignant Melanoma of Soft Parts the N-terminal region of EWS is fused to C-terminal region of the cAMP-inducible transcription factor ATF1. The EWS/ATF1 fusion protein binds to ATF sites present in cAMP-responsive promoters via the ATF1 bZIP domain and activates transcription constitutively in a manner that is dependent on an activation domain (EAD) present in EWS. To further define the requirements for trans-activation we have performed mutational analysis of EWS/ATF1 in mammalian cells and report several new findings. First, trans-activation by EWS/ATF1 does not require dimerisation with other ATF family members present in mammalian cells. Second, in contrast to the earlier suggestion of an allosteric role, the EAD can act directly. Third, determinants of trans-activation are dispersed throughout the EAD and cooperate synergistically to produce potent trans-activation. We also report that the region of EWS containing the EAD can activate transcription in Yeast. This latter finding might enable a genetic approach to understanding the mechanism of transcriptional activation by EWS and development of high-throughput screens for EWS inhibitors.

Amino Acid Sequence↗
PubMed1998

Experimental System for X-ray Cone-Beam Microtomography

: A laboratory test of X-ray tomography employing a diverging beam of X-rays rather than the usual parallel X-ray beam is described. We chose to test and demonstrate the advantages of divergent beam tomography by imaging an extracted juvenile human premolar using an ordinary dental X-ray source and a cooled CCD camera. Experiments with a three-piece cover-glass sample and with the human tooth demonstrated that three-dimensional reconstruction can be achieved at 34 µm per pixel resolution employing an X-ray tube spot 800 µm in its smallest direction without requiring close contact with the fluorescent screen. Reconstruction of a 256 x 256 pixel single-plane image from 100 projection images took only 45 sec on a personal computer with a Pentium 166 MHz processor. We have also demonstrated a volume reconstruction of 256 x 256 x 256 voxels from the data. Successful extension of this work to submicrometer projection X-ray microscopy is predicted. Improved resolution of medical tomography is another possible application.

Journal Article↗
PubMed1998

Profibrinolytic properties characterize a stably transformed human endothelial cell line.

A stable immortalized venous endothelial cell (IVEC) line, obtained by transfection of human umbilical vein endothelial cells (HUVEC), retains many normal differentiated endothelial characteristics. We compared the fibrinolytic activities of IVEC and HUVEC, and observed that IVEC express a more profibrinolytic phenotype than HUVEC, since they bind and activate plasminogen more efficiently, produce more tissue plasminogen activator and urokinase-type plasminogen activator antigens, and secrete less plasminogen activator inhibitor-1 antigen both under basal conditions and after stimulation with lipopolysaccharide, phorbol ester and tumor necrosis factor. Moreover, immunostaining and Western blotting of IVEC for the plasminogen/tissue plasminogen activator receptor annexin II, as well as Northern blotting of annexin II mRNA, revealed similar patterns of surface expression in IVEC and HUVEC. Plasminogen activator inhibitor-2 is expressed similarly in both cell types. IVEC may be a useful human model for functional and pharmacological explorations and modulations of fibrinolytic system components.

Annexin A2↗