Biomedical subjects

K Shi

Publications and source records attributed to K Shi.

At least 19 recordsLinked to original sources

PubMed2006

Different effects of chilling on respiration in leaves and roots of cucumber (Cucumis sativus).

The effects of chilling on respiration (SHAM-resistant, cytochrome pathway and KCN-resistant, alternative pathway), temperature sensitivity, relative electrolyte conductivity, and degrees of oxidative stress (H(2)O(2) and malonaldehyde (MDA) contents) were separately examined in leaves and roots of cucumber (Cucumis sativus L.). After chilling at 8 degrees C for 4 days, both total respiration and KCN-resistant respiration in roots increased at different measurement temperatures. In contrast, SHAM-resistant respiration remained unchanged. In comparison, chilling significantly decreased the total respiration in leaves and this decrease was mostly due to a decrease in SHAM-resistant respiration. Chilling apparently decreased the sensitivity of KCN-resistant respiration to changes of temperature. The reduction levels of ubiquinone pool (UQr/UQt) increased both in chilled leaves and roots whilst pyruvate content increased only in chilled roots, but not in chilled leaves. Furthermore increases of H(2)O(2) and MDA contents were much greater in leaves than in roots. The same trend was also observed for ion leakage from tissues. Taken together, the results suggested that the higher chilling tolerance of roots was associated with their high total respiration and KCN-resistant respiration.

Cold Temperature↗

PubMed2006

Wavelength division scanning for two-photon excitation fluorescence imaging.

We investigate wavelength division scanning for two-photon excitation fluorescence imaging. Two-photon imaging using lateral wavelength division scanning is demonstrated. In addition, we theoretically analyse the spatial and temporal properties of a femtosecond laser beam focused by a Fresnel lens and investigate the feasibility of axial scanning using wavelength division.

Microscopy, Confocal↗

PubMed2004

Comparison of the activities of multinucleated bone-resorbing giant cells derived from CD14-positive cells in the synovial fluids of rheumatoid arthritis and osteoarthritis patients.

OBJECTIVE: To investigate the morphology and function of multinucleated bone-resorbing giant cells derived from CD14-positive cells in the synovial fluids (SF) of patients with rheumatoid arthritis (RA) or osteoarthritis (OA). METHODS: CD14-positive cells were obtained by magnetic-activated cell sorting of primary cultures of mononuclear cells from the SF. Multinucleated bone-resorbing giant cells were induced from the CD14-positive cells in the presence or absence of cytokines. We examined various characteristics, including osteoclast markers, fusion index and bone-resorption activities of the multinucleated giant cells. RESULTS: Multinucleated giant cells were induced from the CD14-positive cells in the SF of the RA and OA patients by the addition of interleukin (IL)-3, IL-5 and IL-7, or granulocyte-macrophage colony-stimulating factor (GM-CSF), respectively. These multinucleated giant cells were positive for tartrate-resistant acid phosphatase (TRAP), carbonic anhydrase II, actin, vitronectin receptor and the calcitonin receptor. However, the average values for the number of nuclei, fusion index and bone-resorption functions of the SF cells from the RA patients were significantly higher than those derived from the OA patients. CONCLUSION: These results suggest that the induction and activities of multinucleated bone-resorbing giant cells may play a pivotal role in bone destruction, and that these processes may be enhanced significantly in RA patients.

Adult↗

PubMed2002

Early closure of growth plate causes poor growth of long bones in collagen-induced arthritis rats.

Abnormalities of the epiphyseal growth plate that occur in collagen-induced arthritis (CIA) were studied. CIA was induced in 6-week-old Lewis rats by immunization with type II collagen. Radiographic examination revealed the early closure of the epiphyseal growth plate with growth retardation of the femur and tibia. Histological evaluation confirmed the early closure of the epiphyseal growth plate accompanied by decreased intensity of safranin-O staining indicating decreased amounts of proteoglycans in the extracellular matrix (ECM) of the cartilage. Immunohistochemical methods showed that the number of chondrocytes expressing matrix metalloproteinase (MMP)-3 and/or vascular endothelial growth factor (VEGF) increased in the growth plates of CIA rats. This study confirmed that disturbances of long bone growth with early closure of the epiphyseal growth plates occur in CIA. There appeared to be overexpression of MMP-3, which may be involved with proteoglycan degradation. Additionally, VEGF, which is associated with cartilage ossification and angiogenesis, might also play a role in this event. Further clarification of the mechanism of the growth disturbance in CIA may yield clinical benefits, especially in prevention of the premature closure of growth plate that is seen in juvenile rheumatoid arthritis and other diseases.

Journal Article↗

PubMed2001

Lymphoid chemokine B cell-attracting chemokine-1 (CXCL13) is expressed in germinal center of ectopic lymphoid follicles within the synovium of chronic arthritis patients.

A unique feature in inflammatory tissue of rheumatoid arthritis (RA) is the formation of ectopic lymphoid aggregates with germinal center (GC)-like structures that can be considered to contribute to the pathogenesis of RA, because local production of the autoantibody, rheumatoid factor, is thought to be a causative factor in tissue damage. However, the factors governing the formation of GC in RA are presently unknown. To begin to address this, the expression of B cell attracting chemokine (BCA-1) (CXCL13), a potent chemoattractant of B cells, was examined in the synovium of patients with RA or with osteoarthritis (OA). Expression of BCA-1 mRNA was detected in all RA samples, but in only one of five OA samples. Lymphoid follicles were observed in four of seven RA samples and in two of eight OA samples, and in most of them BCA-1 protein was detected in GC. BCA-1 was not detected in tissues lacking lymphoid follicles. Notably, BCA-1 was detected predominantly in follicular dendritic cells in GC. CD20-positive B cells were aggregated in regions of BCA-1 expression, but not T cells or macrophages. These data suggest that BCA-1 produced by follicular dendritic cells may attract B cells and contribute to the formation of GC-like structures in chronic arthritis.

Adult↗

PubMed2001

Expression of proteinases and inflammatory cytokines in subchondral bone regions in the destructive joint of rheumatoid arthritis.

OBJECTIVE: We previously described abnormalities in the bone marrow of patients with rheumatoid arthritis (RA), but were able to shed little light on the pathogenic roles of inflammatory cytokines and proteinases in joint destruction in the subchondral region in RA. This is the first report to describe the co-localization of cytokines and proteinases in this area. METHODS: Decalcified paraffin-embedded sections from 10 patients with RA and five patients with osteoarthritis (OA) were examined for the immunolocalization of cathepsins B, K and L and the localization of messenger RNAs for interleukin 1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha) and matrix metalloproteinase 9 (MMP-9). The cells were double-stained with anti-CD68 or anti-prolyl 4-hydroxylase (PH) antibody. RESULTS: An immunohistochemical study confirmed the expression of cathepsins B and L by CD68-positive mononuclear cells at the sites of significant cartilage and bone erosion from the subchondral region in all RA specimens. Osteoclast-like cells showed intense staining for cathepsin K and MMP-9. Osteoblast-like cells strongly expressed MMP-9. Analysis of serial sections revealed that expression of the IL-1beta and TNF-alpha genes occurred near that of the cathepsins and MMP-9 in the subchondral region. CONCLUSION: We conclude that inflammatory cytokines and tissue-damaging proteinases play important roles in joint destruction in the subchondral region in RA.

Adult↗

PubMed2001

Crystal structures of two forms of a 14-mer RNA/DNA chimer duplex with double UU bulges: a novel intramolecular U*(A x U) base triple.

The RNA/DNA 14-mer, (gguauuucgguaCc)2 with consecutive uridine bulges (underlined) on each strand has been determined in two crystal forms, spermine bound (Sp-form) and spermine free (Sp-free). The former was solved by the MAD method with three-wavelength data collected at Brookhaven National Laboratory (BNL); the later isomorphous structure was solved by the molecular replacement method using data collected on our Raxis IIc imaging plate system. The two crystal forms belong to the space group C2 with one molecule of double-stranded 14 mer in the asymmetric unit. The Sp-form has cell constants, a = 60.06, b = 29.10, c = 52.57 A, beta = 120.79 degrees and was refined to 1.7 A resolution with a final Rwork/Rfree of 19.8%/22.7% using 8,549 independent reflections. The Sp-free structure has cell constants, a = 60.06, b = 29.58, c = 52.50 A, beta = 120.85 degrees and was refined to 1.8 A with a final Rwork/ Rfree of 20.8%/23.2% using 6,285 unique reflections. The two structures are identical, except that the Sp-form has a spermine bound in the major groove, parallel to the RNA helical axis. One of the uridine bulges forms a novel intramolecular U*(A x U) base triple. The helices are in the C3'-endo conformation (A-form), but the bulges adopt the C2'-endo sugar pucker. Furthermore, the bulges induce a kink (30 degrees) in the helix axis and a very large twist (55 degrees) between the base pairs flanking the bulges. The Sp-form has one Mg2+ ion whereas the Sp-free form has two Mg2+ ions.

Chimera↗

PubMed2000

Stromal cell-derived factor-1-CXC chemokine receptor 4 interactions play a central role in CD4+ T cell accumulation in rheumatoid arthritis synovium.

Rheumatoid arthritis (RA) is characterized by the accumulation of CD4(+) memory T cells in the inflamed synovium. To address the mechanism, we analyzed chemokine receptor expression and found that the frequency of CXC chemokine receptor (CXCR)4 expressing synovial tissue CD4(+) memory T cells was significantly elevated. CXCR4 expression could be enhanced by IL-15, whereas stromal cell-derived factor (SDF)-1, the ligand of CXCR4, was expressed in the RA synovium and could be increased by CD40 stimulation. SDF-1 stimulated migration of rheumatoid synovial T cells and also inhibited activation-induced apoptosis of T cells. These results indicate that SDF-1-CXCR4 interactions play important roles in CD4(+) memory T cell accumulation in the RA synovium, and emphasize the role of stromal cells in regulating rheumatoid inflammation.

Adjuvants, Immunologic↗

PubMed2000

The crystal structure of the octamer [r(guauaca)dC]2 with six Watson-Crick base-pairs and two 3' overhang residues.

The crystal structure of an alternating RNA octamer, r(guauaca)dC (RNA bases are in lower case while the only DNA base is in upper case), with two 3' overhang residues one of them a terminal deoxycytosine and the other a ribose adenine, has been determined at 2.2 A resolution. The refined structure has an Rwork 18.6% and Rfree 26.8%. There are two independent duplexes (molecules I and II) in the asymmetric unit cell, a = 24.95, b = 45.25 and c = 73.67 A, with space group P2(1)2(1)2(1). Instead of forming a blunt end duplex with two a+.c mispairs and six Watson-Crick base-pairs, the strands in the duplex slide towards the 3' direction forming a two-base overhang (radC) and a six Watson-Crick base-paired duplex. The duplexes are bent (molecule I, 20 degrees; molecule II, 25 degrees) and stack head-to-head to form a right-handed superhelix. The overhang residues are looped out and the penultimate adenines of the two residues at the top end (A15) are anti and at the bottom (A7) end are syn. The syn adenine bases form minor groove A*(G.C) base triples with C8-H...N2 hydrogen bonds. The anti adenine in molecule II also forms a triple and a different C2-H...N3 hydrogen bond, while the other anti adenine in molecule I does not, it stacks on the looped out overhang base dC. The 3' terminal deoxycytosines form two stacked hemiprotonated trans d(C.C)+ base-pairs and the pseudo dyad related molecules form four consecutive deoxyribose and ribose zipper hydrogen bonds in the minor groove.

Adenine↗

PubMed2000

Is there immune dysregulation in symptomatic Gulf War veterans?

Many Gulf War veterans complain of a variety of symptoms including skin rashes and joint pain which may have a common immunological basis. Other Gulf War veterans have post-traumatic stress disorder (PTSD), an anxiety disorder associated with chronic stress. Whether or not chronic stress may affect the capacity to resist disease has not been fully delineated, but recent work suggests that a dysregulated balance of cytokines produced by T helper cells of the immune system may play a role in stress-related illnesses. It is known that a balanced immune response (cell-mediated and humoral immunity) is an important defense mechanism. Although the mechanism(s) by which a change in immune system balance occurs is not clear, it may be secondary to stress-induced changes in hormones such as cortisol and catecholamines, both of which have been implicated in altering levels of cellular or humoral immunity. For these reasons, we are investigating the function of both the cellular and humoral arms of the immune system as well as the cytokine patterns associated with these different functions in symptomatic Gulf War veterans and control groups consisting of asymptomatic Gulf War veterans and symptomatic non-Gulf War veterans.

Adult↗

PubMed2000

Nonunited avulsion fractures of the intercondylar eminence of the tibia.

We report 3 cases of nonunited avulsion fracture of the intercondylar eminence of the tibia. Characteristics of the clinical symptoms were limitation of knee extension, pain at knee extension, and a small amount of anterior instability. For the patient with a normal anterior cruciate ligament (ACL), the fragment was fixed by sutures with a button after curettage of the fibrous tissue. Two patients underwent endoscopic ACL reconstruction using quadrupled semitendinosus tendon because their ACLs had degenerated. Since the technique of ACL reconstruction under arthroscopic control has been well refined, endoscopic ACL reconstruction is considered to be 1 of the surgical options for nonunited avulsion fracture with symptomatic anterior instability if the ACL is degenerated.

Adult↗

PubMed2000

Transcription factor decoy for NFkappaB inhibits cytokine and adhesion molecule expressions in synovial cells derived from rheumatoid arthritis.

OBJECTIVE: Numerous cytokines are expressed in lesions of synovial hyperplasia of patients with rheumatoid arthritis (RA), and their pathophysiological contributions have been the subject of speculation. These genes are regulated by the transcription factor NFkappaB which in turn is activated by tumour necrosis factor-alpha (TNF-alpha) and cytokines. In this study we examined the inhibition of the production of pro-inflammatory cytokines, adhesion molecule and matrix metalloproteinase (MMP) from synovial tissue of patients with RA by the introduction of synthetic double-stranded DNA with high affinity for the NFkappaB binding site. METHOD: NFkappaB decoy oligonucleotides (ODN) were introduced with the aid of the haemagglutinating virus of Japan (HVJ)-liposome method into synovial tissue or synovial cells derived from patients with RA. The levels of interleukin-1beta (IL-1beta), IL-6, TNF-alpha, intercellular adhesion molecule-1 (ICAM-1) and MMP-1 were determined by means of enzyme-linked immunosorbent assay (ELISA) and Northern blotting analysis. A cell counting kit was used to study the effect of NFkappaB decoy ODN on synovial cell proliferation. RESULTS: The production of these mediators was significantly inhibited by the introduction of NFkappaB decoy ODN compared with the effect of scrambled decoy ODN. Transfection of NFkappaB decoy ODN resulted in a significant inhibition of synovial cell proliferation as compared with that of scrambled decoy ODN. CONCLUSION: The results demonstrated in this study suggest the potential usefulness of NFkappaB decoy ODN for gene therapy of inflammatory synovitis of RA.

Arthritis, Rheumatoid↗

PubMed2000

Foot deformities in rheumatoid arthritis and relevance of disease severity.

OBJECTIVE: To investigate foot deformities in rheumatoid arthritis (RA) in relation to the disease severity. METHODS: Radiographs of 100 weight bearing feet of 50 patients who had had RA for >10 years (mean 13.5 years) were studied. The patients were classified into 2 study groups according to the severity of disease. We measured hallux valgus angle (HVA), intermetatarsal angle between first and 2nd (M1/2), and intermetatarsal angle between first and 5th (M1/5) on anteroposterior (AP) radiographs, as well as calcaneal pitch (CP) and first metatarsal pitch (MP) on lateral radiographs. The differences in these angles between the 2 groups (Inter-group study) and the correlations among angles within each group (Intra-group study) were examined. RESULTS: Inter-group study showed significant differences between the 2 groups for all variables. Intra-group study, on the other hand, showed no correlation between variables of the 2 deformities, i.e., splaying of forefoot (M1/2 and M1/5) and flattening of longitudinal arch (CP and MP). Only HVA correlated with the splaying (M1/2 and M1/5) in both study groups. CONCLUSION: Disease severity is related to the progression of foot deformities in RA, but the flattening and the splaying are not correlated with each other. We believe that foot deformities should be treated properly and early, especially for patients who are expected to have severe disease.

Adult↗

PubMed2000

[A molecular cytogenetic study on chromosome anomalies of chronic myeloid leukemia].

OBJECTIVE: To study the bcr/abl fusion gene in chronic myeloid leukemia (CML) cases with Philadelphia chromosome(Ph) negative, and variant Ph translocations and other chromosome anomalies. METHODS: The status of bcr/abl fusion gene in 8 kinds of chromosome anomalies was tested with dual-color fluorescence in situ hybridization (D-FISH) technique. RESULTS: The positive hybridization was demonstrated in 3 cases of variant Ph CML and other 7 cases of standard Ph, respectively. In 2 cases of Ph-negative CML, one case that had karyotype such as 46,XY,t(9;18) showed positive hybridization, the other case with 46,XY,inv(2) showed negative result. CONCLUSION: The result demonstrates that D-FISH technique is reliable for detecting bcr/abl fusion gene. The existence of negative bcr/abl fusion gene CML implies that some other initial events inducing CML might have occurred in such cases.

Adult↗

PubMed2000

[Magnetic drug delivery system--adriamycin-carboxymethyl dextran magnetic nanoparticles].

A novel magnetic drug carrier-carboxymethyl dextran magnetic nanoparticles(CMD MNPs) was prepared. Adriamycin (ADR) was coupled with two types of carrier-neutral dextran MNPs and anionic CMD MNPs, by periodate oxidation. The physico-chemical characteristics and the magnetic guidance effects in vitro and in vivo of ADR-CMD MNPs were studied. The distribution profiles of liver and spleen in mice were studied for both ADR-dextran conjugate MNPs and ADR-CMD conjugate MNPs. The results showed ADR-CMD conjugate MNPs possessed superparamagnetism, the mean diameter was 56 nm, the mass magnetic susceptibility was 1.06 x 10(-4) emu.g-1, and the drug loading was 12.4%. The distribution profiles in liver and spleen revealed that conjugation with neutral dextran MNPs, excessive accumulation of loaded ADR was found in liver and spleen after intravenous administration, while conjugation with CMD MNPs gave a markedly lower concentration in these organs, which indicated less uptake of ADR-CMD conjugate MNPs by reticuloendothelial system(RES) and the advantage of delivering loaded drug to sites other than the RES; thus it opens a new perspective for the active delivery of drug.

Animals↗

PubMed2000

[Detection of fetal cells in maternal blood by fluorescence in situ hybridization].

OBJECTIVE: To isolate fetal nucleated cells from maternal blood and determine its fetal origin. METHODS: Enrichment and isolation of nucleated cells in maternal blood from 20 samples in the first trimester of pregnancy, 20 samples in the mid-trimester of pregnancy, and 15 samples after delivery. Fluorescence in situ hybridization was performed using Y specific probe PY3.4 to identify fetal cells. RESULTS: Fifteen women in the first trimester and 15 women in the mid-trimester of pregnancy carried male fetuses. The rates of positive cells were 1:6528.0 and 1:2783.8 respectively, and there was a highly significant difference when these rates were compared with the positive cells rate of the 10 female fetuses in the same trimesters. No significant difference in positive cells rate was found between 1 week after delivery and the mid-trimester of pregnancy, nor was it found between 3 months after delivery and the 10 samples of female fetuses in the same time. CONCLUSION: These data suggest that fetal cells can be detected as early as from 50 days of gestation in maternal blood, in the meantime, the rate of fetal cells will increase with gestational age. One week after delivery, fetal cells still exist, and 3 months after delivery, the fetal cells will no longer be detected.

Female↗

PubMed1999

[Detection of cytomegalovirus antigens and virus DNA in the peripheral blood after organ transplantation].

OBJECTIVE: To diagnose timely the cytomegalovirus(CMV) infection of recipients after organ transplantation. METHODS: Thirty two organ transplanted recipients were demonstrated for CMV infection based on detection of antigenemia by immunoperoxidase assay, viremia with virus isolation, DNAemia by polymerase chain reaction (PCR) and in situ hybridization (ISH) in peripheral blood samples. RESULTS: Of 89 blood specimens examined, 35(39.3%) were positive for antigenemia, 25(28.1%) for viremia, 37(41.6%) for DNAemia by ISH, and 51(57.3%) for DNAemia by PCR. The results indicated that DNAemia assay with ISH and PCR and antigenemia assay were suitable methods for rapid, early, and sensitive detection of CMV infection. The results correlated with clinical symptoms. CONCLUSION: We suggest that detection of antigenemia, viremia, and DNAemia can monitor CMV infection of organ transplaned recipients and provide indication to antiviral therapy.

Adult↗

PubMed1999

Crystal structure of an RNA duplex r(G GCGC CC)2 with non-adjacent G*U base pairs.

The crystal structure of a self-complementary RNA duplex r(GGGCGCUCC)2with non-adjacent G*U and U*G wobble pairs separated by four Watson-Crick base pairs has been determined to 2.5 A resolution. Crystals belong to the space group R3; a = 33.09 A,alpha = 87.30 degrees with a pseudodyad related duplex in the asymmetric unit. The structure was refined to a final Rworkof 17.5% and Rfreeof 24.0%. The duplexes stack head-to-tail forming infinite columns with virtually no twist at the junction steps. The 3'-terminal cytosine nucleosides are disordered and there are no electron densities, but the 3' penultimate phosphates are observed. As expected, the wobble pairs are displaced with guanine towards the minor groove and uracil towards the major groove. The largest twist angles (37.70 and 40.57 degrees ) are at steps G1*C17/G2*U16 and U7*G11/C8*G10, while the smallest twist angles (28.24 and 27.27 degrees ) are at G2*U16/G3*C15 and C6*G12/U7*G11 and conform to the pseudo-dyad symmetry of the duplex. The molecule has two unequal kinks (17 and 11 degrees ) at the wobble sites and a third kink at the central G5 site which may be attributed to trans alpha (O5'-P), trans gamma (C4'-C5') backbone conformations. The 2'-hydroxyl groups in the minor groove form inter-column hydrogen bonding, either directly or through water molecules.

Base Pairing↗