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Biomedical subjects

X D Fan

Publications and source records attributed to X D Fan.

At least 19 recordsLinked to original sources
PubMed2005

Magnetic resonance arthrography applied to the diagnosis of intraarticular adhesions of the temporomandibular joint.

The purpose of this study is to investigate the diagnostic accuracy of magnetic resonance arthrography (MRAr) on the diagnosis of intraarticular adhesions of the temporomandibular joint (TMJ). Twenty-four patients (31 joints) diagnosed as internal disorders of TMJ were examined to establish the presence, suspicion or absence of intraarticular adhesions through MRAr according to the MRAr radiographic criteria in a blind fashion, subsequent arthroscopy were performed on all 31 joints. The findings were compared to MRAr with those of arthroscopy. The comparison data were assessed by generating receiver operating characteristic curve (ROC curve) and analyzing the area (Az) under the curve with SPSS11.0 software. The area under the ROC curve was 0.91 (0.86, 0.95), P<0.05. MRAr proves to be an excellent modality to diagnose intraarticular adhesions of TMJ.

Adolescent↗
PubMed2001

[The diagnostic value of CT for arteriovenous malformations of jaws].

OBJECTIVE: To evaluate the diagnostic value of CT for arteriovenous malformations (AVM) of jaws. METHODS: 12 cases of central vascular malformations of jaws comprised this study group, 5 cases in maxilla and 7cases in mandible, respectively. The X-ray projection included panoramic radiography, Water's position and posterioanterior and lateral oblique view of mandible. The CT scans were obtained on Somatom ART and the axial and coronal scanning modalities were applied. RESULTS: Radiographically different signs of the AVM of jaws were demonstrated, X plain film has no pathognomic features. The CT features included lytic expansion of bone, expanded space of marrow, obliteration of trabeculae and intact cortex of jaws. These signs were demonstrated very well in bone window setting. There were three forms of demonstrations of AVM of jaws as following: (1) local unilocular, (2) diffused unilocular, (3) multilocular. CONCLUSION: CT is helpful for early diagnosis of AVM of jaws, and can provide the guidance for the direct puncture embolization.

English Abstract↗
PubMed2001

[The DSA features of AVM of jaws].

OBJECTIVE: To evaluate the vascular architecture of AVM of jaws on DSA. METHODS: 12 cases of AVM of jaws comprised this study group, and 5 cases in maxilla and 7 cases in mandible, respectively. Seldinger technique was applied to carry out carotid angiography under the guidance of DSA machine (PHILIPS V3000). RESULTS: The DSA features of AVM of jaws included varix into the posterior area of jaws. The varix of the maxilla was supplied by the posterior superior alveolar artery and transversal facial artery when the soft tissue was involved, and the varix of the mandible was supplied by the inferior alveolar artery, maxillary and facial artery. CONCLUSION: Angiography is considered necessary for the diagnosis and embolization of AVM of jaws, and the varix is the center of lesion.

English Abstract↗
PubMed2001

[Embolization of AVM of jaws].

OBJECTIVE: To report our experience to embolize the AVM of jaws by direct percutaneous puncture. in conjunction with endovascular therapy. METHODS: 3 cases of AVM of mandible and 3 cases of AVM of maxilla comprised this study group. The patients were embolized with fibered coils, PVA and NBCA. The coils were placed directly into the center of the intraosseous lesion. The procedure was under the guidance of DSA machine (PHILIPS V3000). RESULTS: The acute arterial bleeding in 4 patients was controllable. The other two cases with oozing bleeding and a warm soft mass on the left face with a palpable pulse respectively, their symptoms and signs got improved a lot. The pericoronal oozing of blood in all patients disappeared during a 3 to 24 months follow-up and new bone formation was found in the follow-up radiography. CONCLUSION: The embolization of the AVM of jaws by direct percutaneous puncture in conjunction with endovascular therapy is effective and safe, however the longer follow-up is expected.

English Abstract↗
PubMed2000

Substantia nigra pars reticulata lesion facilitates kainic acid-induced seizures.

The administration of subconvulsive doses of kainic acid (5 mg/kg, intraperitoneally) to rats, with lesion of the substantia nigra pars reticulata (1 week), produced high frequency wet dog shakes and severe convulsive behavior (observed in 60% of the rats). The behavior was not observed in rats treated with kainic acid but without reticulata lesion. The results show that rats with unilateral lesion of the substantia nigra pars reticulata are more vulnerable to seizure stimuli.

Animals↗
PubMed2000

Substantia nigra pars reticulata lesion induces preconvulsive behavior and changes in glutamate receptor gene expression in the rat brain.

The substantia nigra pars reticulata (SNpr) has been proposed to play an important role in the control of the propagation and/or the generation of epileptic seizures. Earlier studies have shown differential effects of the lesion of the SNpr on seizure genesis that demonstrated a regional difference in the anterior and posterior parts of the SNpr in preconvulsive behavior induced by unilateral reticulata injection of dopamine (DA). This study was aimed to investigate some of the underlying mechanisms of the preconvulsive behavior elicited by unilateral SNpr DA injection by the study of changes in the gene expression of glutamate receptor subunits (GluR1, GluR2 and NMDAR1) and of changes in animal behavior following coinfusion of DA and a DA D1 antagonist SCH 23390 into the SNpr. Unilateral injection of exogenous DA into the anterior region of the SNpr induced rapid and short lasting preconvulsive behavior up to wet dog shakes stage and a significant reduction of gene expression for GluR1, GluR2 and NMDAR1 subunits in rat hippocampal subfields including CA1 through CA4 and dentate gyrus (DG) at 1 day after nigral DA injection. The effect was long lasting and persisted for at least 3 weeks. Both preconvulsive behavior and downregulation of glutamate receptor subunit genes were completely blocked by simultaneous coinfusion of DA and SCH 23390. The results suggest, for the first time, that DA D1 receptor in the SNpr may mediate the nigral-involved seizure development. Glutamate desensitization, and/or selective early neuronal damage might be responsible for the downregulation of glutamate receptor subunits by transient preconvulsive activity.

Animals↗
PubMed2000

[Embolization in arteriovenous malformations of maxillofacial region with PVA].

OBJECTIVE: To evaluate the embolization of arteriovenous malformations of the maxillofacial region with PVA. METHODS: 8 cases (male:3, female:5) of arteriovenous malformations of the maxillofacial region comprised this study group. The embolic material used was PVA (Polyvinyl Alcohol Foam) particles (250-500 microm) injected using 4.0 to 3.0 French-size catheters, catheterized selectively in the feeding pedicles of the AVM under the guidance of DSA machine (PHILIPS V3000). RESULTS: Five patients were embolized an a single session, and three patients needed two sessions. Immediate angiographical results showed total disappearance of the AVMs in all patients. Swelling, pulsation, and bruit were disappeared after embolization. Pericoronal oozing of blood and acute arterial bleeding was controllable. Local pain, swelling,and low-grade fever usually lasted from 3 to 7 days after embolization. CONCLUSION: The embolization of arteriovenous malformations of the maxillofacial region with PVA is effective and safe, and the longer follow-up is expected.

English Abstract↗
PubMed1999

Lesion of the substantia nigra pars compacta downregulates striatal glutamate receptor subunit mRNA expression.

This is a study of the effect of the unilateral administration of dopamine (DA) in the pars compacta of the substantia nigra (SN) of the rat on striatal glutamate receptor subunit (GluR1, GluR2 and NMDAR1) gene expression determined by in situ hybridization. The location of the nigral lesion was determined by tyrosine hydroxylase (TH) immunohistochemistry and its extent by the striatal DA and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations. The DA-induced lesions produce significant bilateral reductions in the expression of GluR1 and NMDAR1 subunit mRNA in the medio-lateral striatum, whereas the expression of striatal GluR2 receptors was not changed. The reduction in GluR1 and NMDAR1 subunit mRNA may be the consequence of glutamatergic hyperactivity developed in the presence of a damaged nigro-striatal system and these may be associated with the genesis of some neurodegenerative diseases.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1999

[The Value of CT Scanning in the Diagnosis of Temporomandibular Joint Dysfunction]

OBJECTIVE:To evaluate the role of CT in the diagnosis of temporomandibular joint dysfunction MATERIAL: 48 temporomandibular joints of 26 patients suspecting osseous changes were examined by CT, with 1mm of layer thickness. All patients had Sch llers position projection as comparison. RESULTS:CT is more sensitive to detect the osseous changes of TMJ than Sch llers position projection, but not well demonstrating sclerosis of TMJ. The Sch llers position projection can only shows the lesion of lateral 1/3 of condyle, but CT including total condyle. CONCLUSION: CT is an important and sensitive tool in detecting osseous changes of temporomandibular joint.

Journal Article↗
PubMed1999

[Clinical Application of CT assisted Double Contrast Arthrography of Temporomandibular Joint]

OBJECTIVE:To introduce double-contrast arthrography of TMJ with reformatted sagittal and coronal CT imaging and to evaluate the value of its application in the diagnosis of temporomandibular joint dysfunction. METHODS: 14 patients in whom diagnosis can not be established with conventional arthrography were examined by double contrast arthrography with reformatted sagittal and coronal CT imaging. RESULTS: In double-contrast arthrography with CT imaging, 1 case was normal;1 case had anterior displacement with reduction;2 cases were anterior displacement without reduction, and 8 cases were with disk adhesion. CONCLUSION:The double contrast arthrography with reformatted sagittal and coronal CT imaging was a very important alternative to conventional arthrography, and has special value to demonstrate adhesion of TMJ.

Journal Article↗
PubMed1999

[A Comparative Study of MRI and CT Double-Contrast Arthrography in Diagnosis of Disc Adhesion of TMJ]

OBJECTIVE:To compare the results of CT-assisted double-contrast arthrography and MRI in the diagnosis of adhesion of TMJ. MATERIAL:18 patients with adhesion of TMJ were examined by CT-assisted double-contrast arthrography and MRI, and their results were analysed including position, degree and with or without osseous changes. RESULTS:18 cases of adhesion were demonstrated on CT-assisted double-contrast arthrography, and that only 6 cases of them were diagnosed on MRI.CONCLUSION: CT-assisted double-contrast arthrography is more sensitive and accurate than MRI in demonstrating the disk adhesion of TMJ.

Journal Article↗
PubMed1998

Development of a CD28 receptor binding-based screen and identification of a biologically active inhibitor.

CD28 is a T-cell costimulatory receptor which plays a pivotal role in antigen-induced T-cell response. We have developed a cell-free and scintillation-proximity assay-based screen to search for molecules that inhibit ligand binding to CD28. The assay was shown to be versatile and adaptable to automation for high-throughput screening. Using this assay, we identified an inhibitor of CD28, NP2214. The inhibitor was shown to be active in vitro by suppressing IL-2 synthesis and proliferation of peripheral blood mononuclear cells in response to CD28 costimulation. We also demonstrated the additive effects of NP2214 and cyclosporine A which act mechanistically distinctly in inhibiting costimulation-induced IL-2 synthesis.

Abatacept↗
PubMed1997

Induction of preconvulsive behavior and Fos expression by dopamine-induced nigral lesion in the rat.

The substantia nigra pars reticulata (SNpr) has been proposed to play an important role in controlling the propagation and/or the generation of limbic seizures. Earlier work has shown that SN lesions have differential effects on seizure activity, suggesting that at least two discrete topographical regions mediate anticonvulsant or proconvulsant effects. The present investigation showed that exogenous dopamine (DA; 1.5-2.0 mumol) unilaterally injected into the anterior SNpr induced preconvulsive behavior (starting, immobilization, facial and mouth movements and wet-dog shakes). In addition, these rats showed Fos oncoprotein expression in the limbic system. These effects were observed in 90% of the rats with anterior SNpr DA injection. Rats with posterior SNpr injection did not show preconvulsive behavior nor Fos expression. These results show for the first time that unilateral DA lesion of the anterior portion of SNpr elicits Fos expression and preconvulsive behavior. In addition, the results suggest that lesion of the anterior and posterior regions of SNpr appear to exert different influences in the generation of preconvulsive behavior. The time course of behavior changes and Fos expression was also studied.

Animals↗
PubMed1992

A major T cell antigen of Mycobacterium leprae is a 10-kD heat-shock cognate protein.

Several mycobacterial antigens, identified by monoclonal antibodies and patient sera, have been found to be homologous to stress or heat-shock proteins (hsp) defined in Escherichia coli and yeast. A major antigen recognized by most Mycobacterium leprae-reactive human T cell lines and cell wall-reactive T cell clones is a 10-kD protein that has now been cloned and sequenced. The predicted amino acid sequence of this protein is 44% homologous to the hsp 10 (GroES) of E. coli. The purified native and recombinant 10-kD protein was found to be a stronger stimulator of peripheral blood T cell proliferation than other native and recombinant M. leprae proteins tested. The degree of reactivity paralleled the response to intact M. leprae throughout the spectrum of leprosy. Limiting-dilution analysis of peripheral blood lymphocytes from a patient contact and a tuberculoid patient indicated that approximately one third of M. leprae-reactive T cell precursors responded to the 10-kD antigen. T cell lines derived from lepromin skin tests were strongly responsive to the 10-kD protein. T cell clones reactive to both the purified native and recombinant 10-kD antigens recognized M. leprae-specific epitopes as well as epitopes crossreactive with the cognate antigen of M. tuberculosis. Further, the purified hsp 10 elicited strong delayed-type hypersensitivity reactions in guinea pigs sensitized to M. leprae. The strong T cell responses against the M. leprae 10-kD protein suggest a role for this heat-shock cognate protein in the protective/resistant responses to infection.

Amino Acid Sequence↗
PubMed1992

[Function of lymphocyte beta-adrenergic receptor in depression].

Lymphocyte beta-adrenergic receptor function of 20 depressed patients and 18 healthy volunteers were measured using radioligand binding technique. It was found that the affinity and sensitivity of this receptor were significantly higher in endogenous depressed patients than those in normal controls. After the electro-acupuncture-treatment (EAT), lymphocyte beta-receptor function decreased in patients who responded well to EAT, but still not reached normal level.

Acupuncture Therapy↗
PubMed1991

Lipoarabinomannan, a possible virulence factor involved in persistence of Mycobacterium tuberculosis within macrophages.

Mycobacterium tuberculosis and Mycobacterium leprae, the causative agents of tuberculosis and leprosy, respectively, produce large quantities of lipoarabinomannan (LAM), a highly immunogenic, cell wall-associated glycolipid. This molecule has been previously reported to be a potent inhibitor of gamma interferon-mediated activation of murine macrophages. Studies of the mechanism by which this mycobacterial glycolipid down-regulates macrophage effector functions provide evidence that LAM acts at several levels and that it can (i) scavenge potentially cytotoxic oxygen free radicals, (ii) inhibit protein kinase C activity, and (iii) block the transcriptional activation of gamma interferon-inducible genes in human macrophage-like cell lines. These results suggest that LAM can inhibit macrophage activation and triggering and cytocidal activity and that it may represent a chemically defined virulence factor contributing to the persistence of mycobacteria within mononuclear phagocytes.

Cells, Cultured↗
PubMed1990

Divergent activities of protein kinases in IL-6-induced differentiation of a human B cell line.

Lymphokines including IL-2, IL-4, and IL-6 are involved in the induction of Ig production by activated B cells. We have investigated the role of protein kinases in IL-6-induced IgM secretion by SKW6.4 cells, an IL-6 responsive B cell line. IL-6-stimulated IgM production was inhibited by elevated intracellular cAMP induced either by the addition of dibutyryl cAMP or cholera toxin. The inhibitory effect of elevated intracellular cAMP was blocked by n-(2-(Methylamino)ethyl)-5-isoquinolinesulfonic dihydrochloride (H8), an inhibitor of protein kinase A. H8 did not affect IgM secretion induced by IL-6. In contrast, the addition of 1-(5-isoquinolinesulfonyl)-2-methylpiperizine dihydrochloride (H7), an inhibitor of protein kinase C activity, markedly inhibited IL-6-stimulated IgM production by SKW6.4 cells. H7 and elevated intracellular cAMP inhibited IgM mRNA expression and subsequent IgM synthesis by SKW6.4 cells. SKW6.4 proliferation, as determined by [3H]thymidine incorporation, was not markedly affected by IL-6, dibutyryl cAMP, cholera toxin, H7 or H8. PMA, an activator of protein kinase C, directly stimulated significant IgM secretion by SKW6.4 cells. When added to PMA-stimulated SKW6.4 cells, IL-6 stimulated additional IgM production. This observation suggested that IL-6 could stimulate differentiation without activating protein kinase C. This was confirmed by demonstrating that IL-6 did not stimulate production of diacylglycerol, did not induce the translocation of protein kinase C from the cytosolic compartment to the plasma membrane and could induce SKW6.4 cells to produce IgM after depletion of their cellular protein kinase C by PMA. Taken together these results suggests that IL-6-stimulated IgM production requires utilization of an H7-inhibitable protein kinase that can be inhibited by a protein kinase A-dependent pathway. Despite the fact that PMA can stimulate IgM production in SKW6.4 cells, IL-6 appears to use a protein kinase pathway other than protein kinase C to induce IgM production.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗