Search PubMed⌕ Search

Biomedical subjects

W Y Tseng

Publications and source records attributed to W Y Tseng.

12 recordsLinked to original sources
PubMed2005

Anti-rheumatic gold compounds as sublethal modulators of monocytic LPS-induced cytokine secretion.

The objective of this study was to quantify the ability of sublethal concentrations of several gold compounds to differentially modulate the monocytic secretion of key cytokines that are important in the etiology of rheumatic diseases. Human THP1 monocytic cells were exposed to the anti-rheumatic drugs auranofin (AF), gold sodium thiomalate (GSTM) or HAuCl4 (Au(III)) for 24-72 h. Succinate dehydrogenase (SDH) activity of the monocytes was used to determine sublethal concentrations. Monocytes were then exposed to sublethal concentrations of gold compounds for 72 h, and the activator lipopolysaccharide (LPS) was added (or not) to cultures for the last 6h. The secretion of IL6, IL8, IL10, and TNFalpha were measured in cell supernatants using ELISA. Cytokine secretion was compared among concentrations and gold compounds. SDH experiments established a sublethal concentration range of 0-75 microM for GSTM and Au(III) and 0-0.5 microM for AF. In cytokine experiments, none of the compounds alone activated secretion of any of the cytokines, but all differentially (50-440%, p<0.05) increased LPS-induced secretion of IL6 and IL8 over TNFalpha and IL10. In conclusion, sublethal concentrations of AF, GSTM, and Au(III) all may differentially modulate activation of monocytic cells, and this differential modulation may be important in the mechanisms of action of these compounds.

Antirheumatic Agents↗
PubMed2001

Local capsaicin application to the stellate ganglion and stellatectomy attenuate neurogenic inflammation in rat bronchi.

The present study investigated the contributions of vagal and nonvagal sensory nerve fibers on neurogenic inflammation in rat bronchial airways. A surgical procedure was developed via the rat mediastinum ventral intercostal space to prepare an intercostal opening without causing pneumothorax for performing stellate ganglionectomy alone, thoracic vagus nerve section alone, and stellatectomy plus thoracic vagotomy, and for injecting capsaicin (2 microl, 10 mg/ml) and 6-hydroxydopamine (2 microl, 50 mg/ml) into the ganglion. One week later in our procedure, we investigated if neurogenic inflammation induced by an intravenous injection of capsaicin (300 nmol/ml/kg) and innervation density of substance P-immunoreactive sensory axons could be decreased after chronic denervation in the rat lower airways. The major findings were that surgical removal of the right stellate ganglion and local capsaicin application resulted in a significant attenuation of neurogenic plasma extravasation in the right bronchial tree evoked by systemic capsaicin application. Reduction of neurogenic plasma extravasation was totally abolished by combined stellatectomy and thoracic vagotomy. The number of substance P-containing axons was also greatly decreased following these surgical and capsaicin treatments. It is concluded that sensory nerve fibers from both vagal source and nonvagal (spinal) source, which associated with the stellate ganglion, contributed significantly to neurogenic inflammation in the bronchial airways with a slightly higher contribution from the vagus nerve.

Animals↗
PubMed2001

Validation of diffusion tensor magnetic resonance axonal fiber imaging with registered manganese-enhanced optic tracts.

Noninvasive mapping of white matter tracts using diffusion tensor magnetic resonance imaging (DTMRI) is potentially useful in revealing anatomical connectivity in the human brain. However, a gold standard for validating DTMRI in defining axonal fiber orientation is still lacking. This study presents the first validation of the principal eigenvector of the diffusion tensor in defining axonal fiber orientation by superimposing DTMRI with manganese-enhanced MRI of optic tracts. A rat model was developed in which optic tracts were enhanced by manganese ions. Manganese ion (Mn(2+)) is a potent T1-shortening agent and can be uptaken and transported actively along the axon. Based on this property, we obtained enhanced optic tracts with a T1-weighted spin-echo sequence 10 h after intravitreal injection of Mn(2+). The images were compared with DTMRI acquired with exact spatial registration. Deviation angles between tangential vectors of the enhanced tracts and the principal eigenvectors of the diffusion tensor were then computed pixel by pixel. We found that under signal-to-noise (SNR) of 30, the variance of deviation angles was (13.27 degrees). In addition, the dependence of this variance on SNR obeys stochastic behavior if SNR is greater than 10. Based on this relation, we estimated that an rms deviation of less than 10 degrees could be achieved with DTMRI when SNR is 40 or greater. In conclusion, our method bypasses technical difficulties in conventional histological approach and provides an in vivo gold standard for validating DTMRI in mapping white matter tracts.

Animals↗
PubMed2000

Myocardial fiber shortening in humans: initial results of MR imaging.

PURPOSE: To use diffusion-sensitive magnetic resonance (MR) imaging to obtain images of fiber orientation in vivo and to map fiber shortening in humans by means of integrating such data with strain images. MATERIALS AND METHODS: Images of fiber shortening for midventricular short-axis sections were acquired in eight healthy subjects. Fiber orientation maps obtained by means of diffusion-sensitive MR imaging were coregistered with systolic strain maps obtained by means of velocity-sensitive MR imaging. Fiber shortening was quantified by use of the component of systolic strain in the fiber direction. RESULTS: The results were reproducible among subjects and were consistent with published values. MR imaging of myocardial fibers showed axisymmetric progression of fiber angles from -90 degrees epicardially to +90 degrees endocardially, with maxima near 0 degrees. Fiber shortening (mean, 0.12 +/- 0.01 [SD]) was more uniform than radial, circumferential, longitudinal, or cross-fiber strain or any principal strain. Fiber orientation coincided with the direction of maximum contraction epicardially, with that of minimum contraction endocardially, and varied between these extremes linearly with wall depth (r = 0.6). CONCLUSION: Registered diffusion and strain MR imaging can be used quantitatively to map fiber orientation and its relations to myocardial deformation in humans.

Adult↗
PubMed2000

Magnetic resonance imaging assessment of left ventricular function and wall motion.

Assessment of left ventricular (LV) function is essential for the diagnosis and treatment of cardiac patients. A reliable and noninvasive tool for quantifying global and local LV function is needed. Magnetic resonance (MR) imaging has several unique features that are well suited to clinical examinations: it is noninvasive, does not expose the patient to ionizing radiation, and provides images of high spatial resolution and excellent soft tissue contrast without the need for contrast medium injection. In this paper, I review the reported evidence concerning the validity of MR imaging assessment of LV volume, including end-diastolic volume, end-systolic volume, and ejection fraction, and the validity of using MR imaging to monitor LV wall motion. Abundant evidence from phantom, animal, and human studies supports that MR imaging provides accurate and reproducible information that is substantially superior to that from conventional modalities such as angiographic ventriculography, radionuclide scintigraphy, and echocardiography. A fast MR imaging technique, cine MR imaging, further enhances the clinical feasibility of MR imaging by reducing the scanning time to about 20 minutes. Today, cine MR imaging is widely accepted as a reliable clinical tool. It may be considered an in vivo standard for quantification of LV volume and wall motion. Faster MR imaging techniques, such as TurboFLASH and echo-planar imaging, decrease the examination time to several seconds. This allows evaluation of transient functional changes during pharmacologically or physically induced stress tests.

Humans↗
PubMed1999

Cardiac diffusion tensor MRI in vivo without strain correction.

Cardiac diffusion MRI with diffusion encoding that spans a cardiac cycle is complicated by myocardial strains. This paper presents a method to obtain accurate diffusion data without strain correction. Owing to the synchrony of normal cardiac motion, there are time points in the cardiac cycle, "sweet spots," when the cardiac configuration approximates its temporal mean. If the diffusion is encoded then, the net effect of strain on the observed diffusion approximates zero. To test this, MRI diffusion and strain-rate movies are performed on cyclically deformed gel phantoms and in five normal subjects. In phantoms, the sweet spots predicted from the strain time curves agree with the times when the observed diffusion equals the true diffusion. In humans, the strain prediction of the sweet spots and the locations determined by the diffusion trace show a high correlation, r = 0.99. In all subjects, diffusion MRI presents a fiber orientation pattern comparable to that obtained from a stationary specimen. Magn Reson Med 42:393-403, 1999.

Adult↗
PubMed1997

NMR study of solid C60(gamma-cyclodextrin)2.

A solid complex of C60 with gamma-cyclodextrin (gamma-CyD) was examined with NMR spectroscopic methods in order to understand the dynamics of C60, and the interaction between C60 and gamma-CyD. A 13C solid-state cross-polarization magic angle spinning (CP/MAS) NMR spectra shows C60 resonance at 142.6 ppm. This provides the evidence of interaction between 13C spins in C60 and 1H spins in the gamma-CyD host. Ambient temperature experiments on the 13C CP/MAS NMR, with varying contact time, shows that the water associated with gamma-CyDs plays an important role in the nuclear relaxation processes. The dynamics of C60 in gamma-CyD was investigated using temperature and field-dependent 13C spin-lattice relaxation time measurements. The influence of water on the dynamics of C60 was less significant below 250 K.

Carbon↗
PubMed1992

Multiplanar gradient recalled images of the knee: comparison of different flip angles and echo times.

To determine the most appropriate combination of echo time (TE) and flip angle in gradient echo images of the knee, the authors used different TEs (10, 20 and 30 msec) and flip angles (10, 30, 50, 70, 90, 120 and 150 degrees) to perform a systematic study of MRI on 10 volunteer knees. Contrast-to-noise ratios of cartilage-fat, fluid-cartilage, fluid-fat and fluid-ligament were calculated and compared. Images with a 30-degree flip angle combined with 20 msec of TE were found to have the best contrast-to-noise ratios in both objective data analysis and subjective observation. Hyaline cartilage of the knee was hyperintense and was well delineated on this pulse sequence, appearing distinct in contrast to the intra-articular fluid. It is concluded that this T2-weighted gradient echo pulse sequence is an alternative to conventional spin echo T2-weighted imaging of the knee.

Echo-Planar Imaging↗
PubMed1991

Burkitt's and non-Burkitt's type lymphoma: clinicopathological and radiological manifestations.

Nine cases of Burkitt's type and 5 case of non-Burkitt's type small, non-cleaved cell lymphoma were retrospectively studied to evaluate their clinical and radiological manifestations. In the Burkitt's group, the median age of onset was 9 years old; the male to female ratio was 2:1; and the most frequent presentation was abdominal mass. These features conformed to those of non-endemic (or American) type Burkitt's lymphoma. In comparison with the Burkitt's group, less male-predominance (M:F = 2:3) and cervical mass as the most frequent initial symptom were found in the non-Burkitt's group. Plain films and computed tomographies were collected to evaluate the encroachment of the disease into various organs or compartments. There was a statistically significant correlation in site of the main mass between these two types; the Burkitt's type prefers extranodal, whereas the non-Burkitt's type prefers nodal, involvement. Computed tomographic appearance of Burkitt's lymphoma was also analyzed and summarized by the following five aspects: (1) tumor location-predominantly in the abdomen or head/neck region; (2) tumor density-rather homogeneous and slightly less than that of muscle; (3) tumor margin-often well-localized with distinct contrast to adjacent normal tissue; (4) extranodal predilection- the most frequent pattern of involvement; and (5) bony chang-often mild, despite the size of the mass.

Adolescent↗
PubMed1991

Solid and papillary neoplasm of the pancreas: report of three cases.

We report 3 cases of solid and papillary neoplasm of the pancreas, which is a rare pancreatic tumor with distinct clinicopathologic characteristics. Sonographic, computed tomographic (CT) and gross pathologic findings of these 3 patients were obtained and compared. The tumors had a smooth, enhanced capsule and variable internal architecture. Two of the tumors appeared to be of the heterogeneous soft tissue density type, while one of the tumors was of the mixed solid and cystic type. Because the CT appearance of this tumor is subject to variation, it should be differentiated from other pancreatic lesions with variable CT appearances. Several CT features such as soft tissue density of the mass in a precontrast study, a well-enhanced capsule and the absence of pancreatic or biliary duct dilatation, as well as the characteristic young-female predilection, may aid in a correct diagnosis before surgery.

Adolescent↗
PubMedDate not supplied

The effect of curing light intensity on the cytotoxicity of a dentin-bonding agent.

Various dentin-bonding agents (DBAs) have been widely used to improve the bonding strength of dental resins and to prevent microleakage at the resin-dentin interface, although DBA may exert potentially detrimental effects upon dental pulp. In this study, a DBA (Scotchbond Multi-purpose) cured at different light intensities (100, 200 and 300-mW/cm2) for 10 seconds was extracted with Dulbecco's modified Eagle's medium (DMEM) for 24 hours. Thereafter, pulp cells (1 x 10(4) cells/well) were exposed to DMEM with or without DBA extract for 12 hours, 24 hours and five days. Pulp-cell cytotoxicity was measured with a modified 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. No significant cytotoxicity of DBA eluents on pulp cells was found for the 12-hour exposure group. Following 24-hour exposure of cells to DBA cured at 100-mW/cm2, pulp cells became rounder, more retracted and lost some cellular processes as compared to controls. Five-day exposure of pulp cells to DBA extract cured by light at levels of 100, 200 and 300 mW/cm2, respectively, led to a growth retardation of 26%, 48% and 70% as analyzed by the inhibition of mitochondrial dehydrogenase activity. These results indicate that DBA may exert some cytotoxic effects upon dental pulp, especially when DBA-curing is insufficiently complete, as may occur at a low light intensity.

Cell Division↗