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Biomedical subjects

Q Shi

Publications and source records attributed to Q Shi.

At least 73 records · Page 4Linked to original sources
PubMed2001

Recombinant single chain cardiac troponin I-C polypeptides: superior calibration and control materials for cardiac troponin I immunoassays.

There has been a need to create stable and reproducible calibration and control materials for cardiac troponin I assays. Free troponin I, native or recombinant, has been known to be unstable, while troponin CI complex can be easily dissociated in low concentrations or in the presence of chelating agents. In order to overcome these difficulties, two single chain troponin I-C polypeptides have been engineered and expressed separately in Escherichia coli. One consists of a full-length of human cardiac troponin I and C, termed as ScTnI-C and the other consists of a stable fragment (aa28-110) of human cardiac troponin I and a full-length troponin C, termed as ScTnI-C-2. Both ScTnI-C and ScTnI-C-2 were purified to homogeneity by affinity chromatography using anti-cTnI monoclonal antibodies. ScTnI-C and ScTnI-C-2 have apparent molecular weights of 45 kD and 30 kD by SDS-PAGE, respectively. Stability studies by Stratus showed that ScTn I-C and ScTnI-C-2 were stable for 4 months at 2-8 degrees C and at least one year at -20 degrees C. When incubated in human serum at 37 degrees C, ScTnI-C-2 was more resistant to proteolysis than ScTnI-C. ScTnI-C can be recognized by all commercial TnI immunoassays with excellent activity. ScTnI-C-2 can be recognized by all immunoassays that target the stable region of cardiac troponin I. Judging by their performances, ScTnI-C and ScTnI-C-2 are both superior materials to be used as calibrators and controls in clinical laboratories.

Antibodies, Monoclonal↗
PubMed2001

[Studies on the supercritical-CO2 fluid extraction of complex prescription Danshen-Jiangxiang].

This paper first reported the supercritical-CO2 fluid extraction of complex prescription Danshen-Jiangxiang. With the active constituents and yield of extracts as index, the each other effect of each drug and effect on total complex prescription in extraction were studied. And the effects of pressure and temperature were also studied. The results showed the effects were different in complex prescription extraction and single prescription. Active constituents can be extracted, but a obvious effect exist each other and effects together the yield of extract, extraction rate and content of active constituents of complex prescription extraction, which are concerned in extraction conditions. These study results have important reference on the modernization of traditional Chinese medicines.

Carbon Dioxide↗
PubMed2001

[Bo tuo, a study on the reasons of its denomination].

Research is made on the reasons of Bo tuo's denomination by studying its got - up method and the evolution of these two characters' font, in order to get a more rational commentary. Discussion is made on each variant forms of Bo tu, so as to explain the reasons of the variation.

China↗
PubMed2001

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma of the salivary gland.

OBJECTIVE: To study the histopathologic features and pathogenesis of mucosa-associated lymphoid tissue lymphoma (MALT-oma) of salivary glands. METHODS: Clinical data, paraffin-embedded sections, immunohistochemical slides (SP method) and electron microscopic features of surgical specimens of 32 cases of salivary gland MALT-oma were studied. RESULTS: The patients were 27 males and 5 females, with a mean age of 54.76 years. The lesions were located in the parotid area in 17 cases, and in the submandibular gland in the remaining 15 cases. Much of the MALT-oma was replaced by infiltration of a great amount of centrocyte-like cells (CCL) as background and occasional large cells (centroblast- or immunoblast-like). In MALT-omas "lymphoepithelial lesions" were present. Immunohistochemically, CD20 expression was found to be positive and CD45RO expression was negative in all MALT-omas. CONCLUSION: Most of the MALT-omas are low grade malignant tumors and have a "homing back" phenomenon. The cases were managed by surgery and chemotherapy. In a few MALT-omas which turned into high grade malignant tumors, the prognosis was poor. Acquired MALT may develop as a reaction to autoimmune disease and infection. Hyper-immune reaction and MALT hyperplasia under stimulation may result in myoepithelial sialadenitis and lead to MALT-oma of the salivary gland.

Adolescent↗
PubMed2001

The relationship between cartilage end-plate calcification and disc degeneration: an experimental study.

OBJECTIVE: To study the relationship between cartilage end-plate calcification and intervertebral disc degeneration. METHODS: An experimental model of cervical disc degeneration in rabbits was established by resection of the cervical supraspinous and interspinous ligaments and detachment of the posterior paravertebral muscles from the cervical vertebrae. Mechanical instability in the cervical spine elicited by this surgical intervention accelerated the process of intervertebral disc degeneration. The extent of intervertebral disc degeneration was graded in morphologically, and the thicknesses of the calcified layer and the uncalcified layer of the cartilage end-plate were measured in each degenerated cervical disc. RESULTS: In less severely degenerative cervical discs, the morphology of the cartilage end-plate showed nearly normal construction, and the tidemark was clear. In severely degenerative discs, the matrix and cells showed fibrosis, the tidemark advanced, and the calcified cartilage thickened. There exists a positive correlation between the thickness of the calcified layer of the cartilage end-plate and the degree of cervical disc degeneration. CONCLUSION: The calcification of the cartilage end-plate is the key factor that initiates and promotes cervical disc degeneration.

Animals↗
PubMed2001

[Primary cutaneous CD30-positive anaplastic large cell lymphoma].

OBJECTIVE: To analyse the clinical manifestations, pathological and immunohistochemical features of 9 cases of primary cutaneous CD30-positive anaplastic large cell lymphoma (ALCL) in order to improve the criteria for its early and differential diagnosis. METHODS: Histopathological method was used to study the morphological characteristics. Immunohistochemical stainings (SP or ABC method) for leukocyte common antigen (LCA), CD20, CD30, CD45RO, CD68, epithelium membrane antigen (EMA), cytokeratin (CK) and HMB45 were applied to the routine paraffin sections of all the 9 cases. RESULTS: The 9 cases of primary cutaneous CD30-positive ALCL consisting of 6 males and 3 females, aged 31 to 84 years (mean 58.2 years). All patients presented with subcutaneous masses or papular eruptions on lower trunk and extremities. Histopathologically, the lesions were composed of numerous large round, oval or pleomorphic cells with abundant cytoplasm, amphophilic or basophilic, and large nucleus with distinct nucleolus. Mitosis was often observed. Multinucleated giant cells and Reed-Sternberg cells may be seen. The neoplastic cells displayed positive antigen markers for CD30 in 9 cases, 6 positive for CD45RO and 3 cases negative for both CD45RO and CD20. Two patients died of metastasis, 2 patients experienced recurrence and 5 patients still well during follow-up. CONCLUSIONS: Primary cutaneous CD30-positive ALCL is a morphologically distinctive neoplasm with a comparatively favorable prognosis. This tumor can be differentiated from other malignant tumors on the basis of histopathologic features and positive CD30 which is of significance.

Adult↗
PubMed2001

[Dynamic observation on imbalance of dynamic and static forces and degenerated cervical intervertebral disc in rats].

OBJECTIVE: To study the relation between biomechanical imbalance and the degree and course of degeneration of cervical intervertebral disc in rats. METHODS: Sixty SD rats, 8 months old, were randomly divided into 6 groups, the control and model groups of 3, 5, 7 months, 10 in each group. The cervical disc dynamic and static forces imbalance of degeneration model was established to assess the degree of degeneration as well as the content some inflammatory mediators (prostaglandin E2, 6-keto-prostaglandin F1 alpha) and collagenase (MMP-1) activity. RESULTS: (1) In 3 months model group and 5 months control group, fibrous ring of intervertebral disc showed some fissure and slight irregular arrangement, nucleus pulposus shrunken or became smaller, mild herniation of nucleus pulposus was seen in some disc. The nucleus pulposus of intervertebral disc in 5 months model group was fibrosed completely and the disc in 7 months model group herniated or became osteophytosis. (2) Compared with the control group of same time period, MMP-1 was increased significantly in the 5 months and 7 months model groups (P < 0.05), and prostaglandin E2 and 6-keto-prostaglandin F1 alpha elevated in the model groups (P < 0.05, P < 0.01). (3) Comparison between model groups, MMP-1 activity in 5 months and 7 months groups was higher than that in the 3 months group (P < 0.05), and 6-keto-prostaglandin F1 alpha was higher in 7 months group than that in 3 months group (P < 0.05). CONCLUSION: Cervical intervertebral disc undergoes a progressive degenerating process. By breaking the dynamic-static balance of neck in rats could accelerate the progression of degeneration. The fact could be used to elucidate the theory of pathogenesis of cervical spondylopathy, dynamic force imbalance in priority and static force imbalance in predominance.

Animals↗
PubMed2000

Retinoic acid-mediated activation of the mouse renin enhancer.

Previous studies demonstrate that the mouse renin gene is regulated by a complex enhancer of transcription located 2.6 kilobases upstream of the transcription start site which is under both positive and negative influence. We demonstrate herein that a positive regulatory element (Eb) is repeated 10 bp upstream (Ec), and both are required for baseline activity of the enhancer. The Eb and Ec core sequences are identical to the consensus sequence for the nuclear hormone receptor superfamily of transcription factors, and transcriptional activity of constructs containing the enhancer is increased after treatment with retinoic acid. Maximal induction requires both Eb and Ec. Expression of endogenous renin and a renin-promoter controlled transgene in As4.1 cells, and kidney renin mRNA in C57BL/6J mice was induced after retinoid treatment. Gel mobility supershift analysis revealed the binding of RARalpha and RXRalpha to oligonucleotides containing both Eb and Ec. Reverse transcriptase-polymerase chain reaction analysis revealed that As4.1 cells express both receptor isoforms, along with RARgamma, but do not express RARbeta, RXRbeta, or RXRgamma. Co-transfection of an expression vector encoding wild-type RARalpha increased enhancer activity, whereas a dominant negative mutant of RARalpha significantly attenuated retinoic acid-induced activity of the enhancer. These results demonstrate the importance of the Eb and Ec motifs in controlling baseline activity of the renin enhancer, and suggest the potential importance of retinoids in regulating renin expression.

Animals↗
PubMed2000

Increased nondisjunction of chromosome 21 with age in human peripheral lymphocytes.

Fluorescence in situ hybridization (FISH) on binucleated cells with chromosome-specific DNA probes provides a convenient way to visualize reciprocal segregation patterns in daughter nuclei, and overcomes most problems related to the artefactual loss or gain of chromosomes that flaw chromosome preparations. In this study, FISH was employed to evaluate age- and sex-effects on spontaneous malsegregation, nondisjunction and loss of chromosome 21 in human lymphocytes after the first division in culture. A total of 68 healthy nonsmokers and nondrinkers of alcohol (37 males and 31 females) were grouped by age as Group I (0-10 years), Group II (20-30 years), Group III (40-50 years) and Group IV (60-70 years), with at least seven subjects per group and sex. FISH with a pericentric chromosome 21 specific DNA probe was carried out on binucleated lymphocytes, cytokinesis-blocked by cytochalasin B (6 microg/ml for 26 h) at 44 h after initiation of cultures. Linear regression analyses demonstrated a significant age-related increase in the frequency of micronuclei without chromosome 21 (MN-21)(r=0.73, p<0.001 in females; r=0.69, p<0.001 in males) in all binucleated cells, with a steeper slope in females (0.1758) than in males (0. 1241). Analysis using the 2x2 chi-square (chi(2)) test on the frequencies of MN-21 showed significant age-related differences in both males and females, except males in Group III and Group IV (p>0. 05). A significant sex-related difference was found only in subjects over 60 years (p<0.05), with females having more MN-21 (12.57 per thousand vs. 8.43 per thousand) than males. Loss of chromosome 21, occurring at mean levels of 0.38 per thousand in all binucleated cells and 0.24 per thousand in binucleated cells containing four FISH signals, was shown not to be age- or sex-related. A positive age-related increase in nondisjunction of chromosome 21 was shown in males (r=0.50, p<0.01), females (r=0.61, p<0.001) and all subjects (r=0.55, p<0.001) by linear regression analysis. An age effect was found only between children and adults (p<0.01 for females, p<0.05

Adolescent↗
PubMed2000

Multicolor fluorescence in situ hybridization analysis of meiotic chromosome segregation in a 47,XYY male and a review of the literature.

The frequencies of aneuploid and diploid sperm were determined in a 47,XYY male using multi-color fluorescence in situ hybridization (FISH) analysis, and compared with those from 10 control donors. A total of 30,078 sperm from the patient was scored, 15,044 by two-color FISH for chromosomes 13 and 21, and 15,034 by three-color FISH for the sex chromosomes using chromosome 1 as an internal autosomal control for diploidy and lack of hybridization. The frequencies of X-bearing (49.73%) and Y-bearing sperm (49.46%) in control males were not significantly different from the expected 50% (chi(2)-test for goodness of fit). The ratio of 24,X (50.60%) to 24, Y sperm (48.35%) in the patient, however, was significantly different from the controls (P = 0.0144, chi(2)-test for independence) and from the expected 1:1 ratio (P = 0.0055, chi(2)-test for goodness of fit). There was no significant increase in the frequency of diploid sperm when compared with the controls (chi(2)-test for independence). Significantly increased frequencies were found for 24,YY (0.07% vs. 0.02%, P = 0.0009) and 24,XY (0.44% vs. 0.29%, P = 0.0025), but not for 24,XX (0.05% vs. 0.05%, P > 0. 05), 24,+13 (0.07% vs. 0.07%, P > 0.05) or 24,+21 sperm (0.21% vs. 0. 18%, P > 0.05) in the 47,XYY male when compared with control donors (chi(2)-test for independence). Our results support the theory that loss of the extra Y chromosome occurs during spermatogenesis in most cells. In this XYY patient there was a significant increase in the frequency of sperm with sex chromosomal abnormalities but no suggestion of an inter-chromosomal effect on autosomes. All 3-color FISH studies in the literature demonstrate a significantly increased risk of gonosomal aneuploidy in XYY males, with the risk being on the order of 1%.

Adult↗
PubMed2000

Influence of nitric oxide synthase II gene disruption on tumor growth and metastasis.

The relationship between nitric oxide (NO) synthase II (NOS II) expression and the metastatic ability of tumor cells is inconclusive. We determined the role of host NOS II expression in the growth and metastasis of the B16-BL6 murine melanoma and M5076 murine ovarian sarcoma cell lines. The cells were either s.c. or i.v. injected into syngeneic wild-type (NOS H+/+) and NOS II-null (NOS H-/-) C57BL/6 mice. Both cell lines produced slightly larger s.c. tumors in NOS H-/- mice than in NOS II+/+ mice. However, B16- BL6 cells produced more and larger experimental lung metastases in NOS II+/+ mice than in NOS II-/- mice, whereas M5076 cells produced fewer and smaller experimental lung metastases in NOS II+/+ mice than in NOS II-/- mice. After activation with IFN-gamma and lipopolysaccharide, macrophages isolated from NOS II+/+ C57BL/6 mice produced NO-dependent cytotoxicity in sarcoma cells, whereas macrophages from NOS II-/- C57BL/6 mice did not. In contrast, activated macrophages produced little to no NO-mediated cytotoxicity in melanoma cells. Immunostaining analyses indicated that NOS II expression was apparent in the metastases growing in NOS H+/+ mice and correlated with increased cell proliferation in B16-BL6 lung metastases but with decreased cell proliferation in M5076 liver metastases. Our data suggest that disruption of host NOS II expression enhanced the growth and metastasis of NO-sensitive tumor cells but suppressed the metastasis of NO-resistant tumor cells, proposing that host-derived NO may differentially modulate tumor progression.

Animals↗
PubMed2000

Position-dependent linkages of fibronectin- integrin-cytoskeleton.

Position-dependent cycling of integrin interactions with both the cytoskeleton and extracellular matrix (ECM) is essential for cell spreading, migration, and wound healing. Whether there are regional changes in integrin concentration, ligand affinity or cytoskeleton crosslinking of liganded integrins has been unclear. Here, we directly demonstrate a position-dependent binding and release cycle of fibronectin-integrin-cytoskeleton interactions with preferential binding at the front of motile 3T3 fibroblasts and release at the endoplasm-ectoplasm boundary. Polystyrene beads coated with low concentrations of an integrin-binding fragment of fibronectin (fibronectin type III domains 7-10) were 3-4 times more likely to bind to integrins when placed within 0.5 microns vs. 0.5-3 microns from the leading edge. Integrins were not concentrated at the leading edge, nor did anti-integrin antibody-coated beads bind preferentially at the leading edge. However, diffusing liganded integrins attached to the cytoskeleton preferentially at the leading edge. Cytochalasin inhibited edge binding, which suggested that cytoskeleton binding to the integrins could alter the avidity for ligand beads. Further, at the ectoplasm-endoplasm boundary, the velocity of bead movement decreased, diffusive motion increased, and approximately one-third of the beads were released into the medium. We suggest that cytoskeleton linkage of liganded integrins stabilizes integrin-ECM bonds at the front whereas release of cytoskeleton-integrin links weakens integrin-ECM bonds at the back of lamellipodia.

3T3 Cells↗
PubMed2000

Enhanced endothelialization and microvessel formation in polyester grafts seeded with CD34(+) bone marrow cells.

The authors have shown accelerated endothelialization on polyethylene terephthalate (PET) grafts preclotted with autologous bone marrow. Bone marrow cells have a subset of early progenitor cells that express the CD34 antigen on their surfaces. A recent in vitro study has shown that CD34(+) cells can differentiate into endothelial cells. The current study was designed to determine whether CD34(+) progenitor cells would enhance vascular graft healing in a canine model. The authors used composite grafts implanted in the dog's descending thoracic aorta (DTA) for 4 weeks. The 8-mm x 12-cm composite grafts had a 4-cm PET graft in the center and 4-cm standard ePTFE grafts at each end. The entire composite was coated with silicone rubber to make it impervious; thus, the PET segment was shielded from perigraft and pannus ingrowth. There were 5 study grafts and 5 control grafts. On the day before surgery, 120 mL bone marrow was aspirated, and CD34(+) cells were enriched using an immunomagnetic bead technique, yielding an average of 11.4 +/- 5. 3 x 10(6). During surgery, these cells were mixed with venous blood and seeded onto the PET segment of composite study grafts; the control grafts were treated with venous blood only. Hematoxylin and eosin, immunocytochemical, and AgNO(3 )staining demonstrated significant increases of surface endothelialization on the seeded grafts (92% +/- 3.4% vs 26.6% +/- 7.6%; P =.0001) with markedly increased microvessels in the neointima, graft wall, and external area compared with controls. In dogs, CD34(+) cell seeding enhances vascular graft endothelialization; this suggests practical therapeutic applications. (Blood. 2000;95:581-585)

Animals↗
PubMed2000

Dynamic Changes of Smooth Muscle and Endothelial Markers in the Early Healing Process of Dacron Vascular Grafts in the Dog, Using RT-PCR.

Previous studies of neointima formation on Dacron vascular grafts mainly focused on the late stages using immunohistochemistry staining for von Willebrand factor (vWF) and smooth muscle (SM) alpha-actin. However, it is impossible to use immunohistochemistry to study the early events of neointima formation, because graft samples lack sufficient cellular material. Therefore, we used reverse transcriptase-polymerase chain reaction (RT-PCR) to demonstrate dynamic changes of SM and endothelial markers during the early stages of neointima formation. Preclotted Dacron grafts were implanted in the descending thoracic aorta of 14 mongrel dogs. Specimens were retrieved at 1-4 weeks. Total RNAs were extracted from mid-portion of graft flow surfaces, and RT-PCR for vWF, SM myosin heavy chain (MHC), and SM alpha-actin were performed and expressed as a ratio to the ribosome s17 signal. SM MHC and vWF mRNA expression was low at 1-2 weeks but elevated at 3-4 weeks (P < 0.05). However, SM alpha-actin mRNA levels were expressed consistently throughout the study period. At 3-4 weeks, vWF mRNA expression was inversely correlated to thrombus formation on the graft flow surface. Increased expressions of SM MHC and vWF mRNA corresponded to the formation of neointima and an endothelial layer at the later stages. However, SM alpha-actin mRNA expression did not vary during the healing process. The application of RT-PCR should permit further studies of gene regulation in the early vascular graft healing process in vivo. This model can also be used to study the molecular events that are involved in SM cell differentiation.

Journal Article↗