51
|
Lin MT, Chen LC, Chen CK, Chen Liu KC, Lee SS. Chemical constituents from Drypetes littoralis. JOURNAL OF NATURAL PRODUCTS 2001; 64:707-709. [PMID: 11421728 DOI: 10.1021/np0005964] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Chemical investigation of Drypetes littoralis yielded three new tricyclic diterpenes, drypetenones A, B, and C (1--3), and one new xanthone (4). Spectral analyses and chemical correlations established the structures as 10S-12-hydroxy-11-methoxy-13-methylpodocarpa-1,5,8,11,13-pentaene-3,7-dione, (1), 10S-12-hydroxy-11-methoxy-13-methylpodocarpa-5,8,11,13-tetraene-3,7-dione (2), 10S-12-hydroxy-6,11-dimethoxy-13-methylpodocarpa-1,5,8,11,13-pentaene-3,7-dione (3), and 1-hydroxy-7-hydroxymethyl-6-methoxyxanthone (4). Complete (13)C NMR assignment of boehmenan D (5) is also made.
Collapse
|
52
|
Chen LC, Chen JW, Wu MH, Liu JC, Lan GY, Wu TC, Chern MS, Chang CY, Chang MS, Ding PY. Differential coronary artery calcification detected by electron beam computed tomography as an indicator of coronary stenosis among patients with stable angina pectoris. Can J Cardiol 2001; 17:667-76. [PMID: 11420578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
BACKGROUND The detection of coronary artery calcification by electron beam computed tomography (EBCT) has been suggested as an indicator of atherosclerosis and coronary artery disease (CAD). There is no consensus on the correlation between coronary calcification and angiographically significant stenosis on an artery-by-artery basis. OBJECTIVE To examine the relationship between coronary calcification score (CCS) and the presence of significant CAD on an artery-by-artery basis in patients with stable angina pectoris. METHODS AND RESULTS EBCT and coronary angiogram (CAG) were evaluated in 71 patients with stable angina and in nine control subjects. The CCSs of each of the four major coronary arteries were highest in patients with significant CAD (n=43), followed by patients with insignificant CAD (n=5), patients with syndrome X (n=23) and control subjects, respectively. Calcification scores of the four major coronary arteries appeared to have different predictive power for significant stenosis on the same vessel. For left main (LM) and left anterior descending (LAD) coronary arteries, CCSs of vessels with significant stenoses were not different from those without significant stenoses (values expressed as medians: LM 0 versus 1; LAD 98.5 versus 70; not significant). Calcification scores of left circumflex (LCX) and right coronary arteries (RCA) were significantly higher in vessels with significant stenosis (LCX 49.5 versus 0; RCA 53 versus 1; P<0.05). CCSs appeared to be moderately useful to predict significant stenoses in these two vessels (areas under receiver operating characteristic curves: LCX 0.68+/-0.08, 95% CI 0.52 to 0.81; RCA 0.71+/-0.08, 95% CI 0.55 to 0.84). CONCLUSIONS The CCSs of RCA and LCX arteries, but not those of LM and LAD arteries, may predict significant angiographic stenosis on an artery-by-artery basis among patients with stable angina pectoris.
Collapse
|
53
|
Chen CC, Yeh CC, Chen CH, Yu MY, Liu HL, Wu JJ, Chen KH, Chen LC, Peng JY, Chen YF. Catalytic growth and characterization of gallium nitride nanowires. J Am Chem Soc 2001; 123:2791-8. [PMID: 11456965 DOI: 10.1021/ja0040518] [Citation(s) in RCA: 463] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The preparation of high-purity and -quality gallium nitride nanowires is accomplished by a catalytic growth using gallium and ammonium. A series of catalysts and different reaction parameters were applied to systematically optimize and control the vapor-liquid-solid (VLS) growth of the nanowires. The resulting nanowires show predominantly wurtzite phase; they were up to several micrometers in length, typically with diameters of 10-50 nm. A minimum nanowire diameter of 6 nm has been achieved. Temperature dependence of photoluminescence spectra of the nanowires revealed that the emission mainly comes from wurtzite GaN with little contribution from the cubic phase. Moreover, the thermal quenching of photoluminescence was much reduced in the GaN nanowires. The Raman spectra showed five first-order phonon modes. The frequencies of these peaks were close to those of the bulk GaN, but the modes were significantly broadened, which is indicative of the phonon confinement effects associated with the nanoscale dimensions of the system. Additional Raman modes, not observed in the bulk GaN, were found in the nanowires. The field emission study showing notable emission current with low turn-on field suggests potential of the GaN nanowires in field emission applications. This work opens a wide route toward detailed studies of the fundamental properties and potential applications of semiconductor nanowires.
Collapse
|
54
|
Lee WI, Yang MH, Lee KF, Chen LC, Lin SJ, Yeh KW, Huang JL. PFAPA syndrome (Periodic Fever, Aphthous stomatitis, Pharyngitis, Adenitis). Clin Rheumatol 2001; 18:207-13. [PMID: 11206345 DOI: 10.1007/s100670050086] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
This paper aims to remind paediatric clinicians to suspect and confirm 'PFAPA' syndrome (Periodic Fever, Aphthous stomatitis, Pharyngitis and cervical Adenitis syndrome). We report two cases of PFAPA syndrome: a 3-year-old healthy boy with atopic rhinitis and a boy aged 8 years 5 months who simultaneously had lymphocytic vasculitis syndrome treated with immunosuppressive drugs. Both met Marshall's criteria. The literature regarding PFAPA syndrome was complied using a Medline search for articles published between 1963 and 1998 and we then reviewed the reference lists of the articles. The Medline search revealed 28 cases with available clinical manifestations, management and prognosis. Our study describes two additional cases. We divided the cases into typical (28 cases) and atypical (two cases) PFAPA syndrome. In typical PFAPA, the age of onset was less than 5 years in most cases and the patients presented 4.9 +/- 1.4 days of fever (100%), pharyngitis (89.3%), cervical adenitis (72.1%), stomatitis (71.4%), malaise (64.3%), headache (60.7%), abdominal pain (53.6%) and nausea/vomiting (17.9%). Afebrile intervals were 3.2 +/- 2.4 months and increased with age. The time from initial onset to final episode was 3 years 7 months +/- 3 years 6 months. The total number of episodes was 8.3 +/- 2.5 (range 6-14). Effective treatment included steroids, tonsillectomy/adenoidectomy and cimetidine. The general outcome was good. In atypical PFAPF, the clinical manifestations were similar to those of typical PFAPA except that the age of onset was more than 5 years, and life-threatening intestinal perforation happened once in a patient with underlying Fanconi's anaemia. It was concluded that typical PFAPA syndrome is benign and can be diagnosed by detailed history-taking and from physical findings during repeated febrile episodes with tests to rule out other periodic fever syndromes. A review of the literatures since the first report in 1987 has shown that typical PFAPA syndrome is not associated with significant long-term sequelae and has a good response to steroids. One patient with atypical PFAPA, who received low-dose steroids for over 1 year, developed intestinal perforation after an increment of the 7-day steroid dose. If an underlying problem requires long-term immunosuppressive medication, it is wiser to choose cimetidine rather than increasing the steroid dosage to resolve atypical PFAPA.
Collapse
|
55
|
Jan JC, Asokan K, Chiou JW, Pong WF, Tseng PK, Chen LC, Chen FR, Lee JF, Wu JS, Lin HJ, Chen CT. X-ray absorption spectroscopy investigations on oxidized Ni/Au contacts to p-GaN. JOURNAL OF SYNCHROTRON RADIATION 2001; 8:827-829. [PMID: 11512946 DOI: 10.1107/s0909049501001911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 01/24/2001] [Indexed: 05/23/2023]
Abstract
X-ray absorption spectroscopy was used to investigate the electronic structure of as-deposited and oxidized Ni/Au contacts to p-GaN and to elucidate the mechanism responsible for low impedance. X-ray absorption near edge spectra of Ni K- and L3,2-edges clearly indicate formation of NiO on the sample surface after annealing. The reason for low impedance may be attributed to increase in hole concentration and existence of p-NiO layer on the surface.
Collapse
|
56
|
Lin YL, Huang JL, Chen LC, Wang CR. Correlation of total and specific serum immunoglobulin E levels with the severity of chronic sinusitis in children. Asian Pac J Allergy Immunol 2001; 19:1-6. [PMID: 11495293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Chronic sinusitis is frequently associated with allergy and asthma. Previous studies have shown that serum immunoglobulin E (IgE) levels correlate with allergy and asthma in adults. Because the role of allergic inflammation in the severity of chronic sinusitis remains controversial in children, we set out to determine whether a correlation exists between serum levels of total and specific IgE and the severity of chronic sinusitis in children. Forty-four children with chronic sinusitis were enrolled in the study. Computed tomographic scans were reviewed and scored for the severity of sinusitis. All children were mite-sensitive. Serum samples were assayed for total IgE and specific IgE antibodies to mite allergen using a fluoroimmunoassay. Fourteen subjects had extensive sinus disease. There was no significant difference in the average of total and specific IgE between the subjects with extensive and limited disease (p = 0.562 and 0.755, respectively). Thirty-four subjects were diagnosed with asthma. The subjects with extensive sinus disease had a higher prevalence of moderate to severe asthma than the subjects with limited disease (p = 0.006), but there was no significant difference in the average of total and specific IgE between the subjects with different severities of asthma. (p = 0.833 and 0.425, respectively). The data suggests that levels of total or specific IgE do not correlate with severity of chronic sinusitis in children. Nonetheless, the severity of chronic sinusitis and asthma correlate well with each other irrespective of total and specific IgE.
Collapse
|
57
|
Pong WF, Yueh CL, Chang YD, Tsai MH, Chang YK, Chen YY, Lee JF, Wei SL, Wen CY, Chen LC, Chen KH, Lin IN, Cheng HF. X-ray absorption studies of carbon-related materials. JOURNAL OF SYNCHROTRON RADIATION 2001; 8:145-149. [PMID: 11512713 DOI: 10.1107/s0909049500019750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2000] [Accepted: 12/05/2000] [Indexed: 05/23/2023]
Abstract
X-ray absorption near-edge structure (XANES) measurements have been performed on nitrogen-doped diamond films with three different dopant concentrations and iron-layer-stabilized carbon nanotube (CNT) structures with various diameters at the C K-absorption edge using the sample drain current mode. The C K-edge XANES spectra of these N-doped diamond films resemble that of the undoped diamond regardless of the dopant concentration, which suggest that the overall bonding configuration of the C atom is unaltered. N dopants are found to reduce the intensities of both the sp2- and sp3-bond-derived resonance features in the XANES spectra. On the other hand, the C K-edge XANES spectra of CNTs indicate that the intensities of the pi* and sigma* bands and the interlayer-state features vary with the diameter of the CNT. This phenomenon may be caused by the Fe-layer-catalysed bending of the graphite sheet and the interaction between C and Fe atoms.
Collapse
|
58
|
Wesselkamper SC, Chen LC, Gordon T. Development of pulmonary tolerance in mice exposed to zinc oxide fumes. Toxicol Sci 2001; 60:144-51. [PMID: 11222881 DOI: 10.1093/toxsci/60.1.144] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
As a result of repeated exposures to inhaled toxicants such as zinc oxide (ZnO), numerous individuals acquire tolerance to the exposures and display reduced symptoms. To ascertain whether tolerance is developed in an animal model, NIH-Swiss mice were exposed to 1.0 mg/m(3) ZnO for 1, 3, or 5 days (1X, 3X, or 5X), and polymorphonuclear leukocyte (PMN) and protein levels in bronchoalveolar lavage (BAL) were measured. Mice acquired tolerance to neutrophil infiltration into the lungs, as total PMNs returned near baseline in 5X-exposed animals as compared to that of the 1X exposure group (1X = 2.7 +/- 0.4 x 10(4), 5X = 0.2 +/- 0.1 x 10(4), mean +/- SE, p < 0.05). Development of tolerance to changes in lavageable protein, however, was not observed (1X = 313 +/- 29 microg/ml, 5X = 684 +/- 71 microg/ml, p < 0.05). Tolerance to PMN influx did not persist following re-exposure to ZnO after 5 days of rest. In contrast to ZnO exposure, following single and repeated exposure to aerosolized endotoxin there was development of tolerance to protein in BAL (1X = 174 +/- 71 microg/ml, 5X = 166 +/- 14 microg/ml, p > 0.05), but not to PMN influx (1X = 5.5 +/- 1.7 x 10(4), 13.9 +/- 1.7 x 10(4), p < 0.05). Induction of lung metallothionein (MT) was also observed in mice exposed once or repeatedly exposed to ZnO, suggesting that MT may play a role in its molecular mechanism.
Collapse
|
59
|
Lo SC, Kai JJ, Chen FR, Chang L, Chen LC, Chiang CC, Ding P, Chin B, Zhang H, Chen F. Four-dimensional dielectric property image obtained from electron spectroscopic imaging series. QJM 2001; 50:497-507. [PMID: 11918416 DOI: 10.1093/jmicro/50.6.497] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/18/2023] Open
Abstract
We have demonstrated a new quantitative method to characterize two-dimensional distributions of energy-dependent dielectric function of materials from low loss electron spectroscopic image (ESI) series. Two problems associated with extracted image-spectrum from the low-loss image series, under-sampling and loss of energy resolution, were overcome by using fast Fourier transformation (FFT) interpolation and maximum entropy deconvolution method. In this study, Black Diamond/Si3N4/SiO2/Si-substrate dielectric layer designed for copper metallization was used as the sample. We show that the reconstructed (FFT interpolated and maximum entropy deconvoluted) image-spectrum obtained from ESI series images can be quantified with the same accuracy as conventional electron energy-loss spectroscopy spectra. Since the analysis of the dielectric function is sensitive to the local thickness of the specimen using Kramers-Kronig analysis, we also developed a new method to quantitatively determine the dielectric constant for low-k materials. We have determined the thickness of the Black Diamond using the extrapolated thickness method from the materials of known dielectric constants. Using Kramers-Kronig formula, the dielectric function map can be deduced from two-dimensional reconstructed single scattering spectra with providing the information of thickness. We proposed a four-dimensional data presentation for revealing the uniformity of the energy dependent property. The accuracy of our methods depends on the thickness determination and on the quality of the reconstructed spectra from the image series.
Collapse
|
60
|
Chen LC, Chou MH, Lin MF, Yang LL. Lack of pharmacokinetic interaction between valproic acid and a traditional Chinese medicine, Paeoniae Radix, in healthy volunteers. J Clin Pharm Ther 2000; 25:453-9. [PMID: 11123499 DOI: 10.1046/j.1365-2710.2000.00313.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE In addition to the standard antiepileptic drugs, traditional Chinese medicines (TCMs) are used for the treatment of epilepsy in oriental countries. The interactions between antiepileptic drugs and TCMs represent a potential problem in clinical application. Because valproic acid (VPA), one of the most widely prescribed antiepileptic drugs, may be administered concomitantly with Paeoniae Radix (PR), one of the famous TCMs, in some epileptic patients, the present study was conducted to evaluate the influences of PR on the pharmacokinetics of VPA. METHOD The pharmacokinetics of VPA were investigated in a randomized, open-label, two-way crossover study. Six healthy volunteers received the following treatments in a crossover design: (i) 1.2 g extract powder of Paeoniae Radix once daily for 7 days and one 200 mg VPA gastro-resistant tablet on day 7 and (ii) one 200 mg VPA gastro-resistant tablet alone on day 7. Serial plasma samples were obtained on day 7. Total and free (unbound) VPA plasma concentrations were determined by fluorescence polarization immunoassay (FPIA). Safety measures included laboratory tests (haematology, serum chemistry and urinalysis) and adverse event monitoring. Statistical comparisons of pharmacokinetic parameters were performed with the Student paired t-test. RESULTS Overall clinical safety was satisfactory. The mean maximum plasma concentration of VPA was attained at within 6 h after oral administration of VPA alone and 3-4 h after oral administration of VPA in combination with PR. The plasma level of VPA declined with a half-life of 11.71 and 11.91 h, respectively. No statistically significant difference was obtained in any of the pharmacokinetic parameters (Tmax, Cmax, AUC, t1/2, MRT, CL/F and Vd/F) of VPA between the two treatments. Also, there was no significant difference in the protein binding rates of VPA. CONCLUSION PR did not significantly affect the absorption, distribution, metabolism and elimination of VPA in healthy volunteers.
Collapse
|
61
|
Fine JM, Gordon T, Chen LC, Kinney P, Falcone G, Sparer J, Beckett WS. Characterization of clinical tolerance to inhaled zinc oxide in naive subjects and sheet metal workers. J Occup Environ Med 2000; 42:1085-91. [PMID: 11094787 DOI: 10.1097/00043764-200011000-00010] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Clinical tolerance to the acute effects of zinc oxide inhalation develops in workers during periods of repeated exposure. The aims of this study were to determine whether clinical tolerance is accompanied by a reduction in the acute pulmonary inflammatory and cytokine responses to zinc oxide exposure and whether tolerance can be demonstrated in sheet metal workers who chronically inhale low levels of zinc oxide. Naive (never-exposed) subjects inhaled 5 mg/m3 zinc oxide on 1 or 3 days and underwent bronchoalveolar lavage 20 hours after the final exposure. Sheet metal workers inhaled zinc oxide on 1 day and control furnace gas on another day. Among naive subjects in whom tolerance was induced, bronchoalveolar lavage fluid percent neutrophils and interleukin-6 (IL-6) levels were significantly decreased compared with subjects who underwent only a single exposure. Sheet metal workers were much less symptomatic, but they still experienced a significant increase in plasma IL-6. The results indicate that clinical tolerance to zinc oxide is accompanied by reduced pulmonary inflammation and that chronically exposed sheet metal workers are not clinically affected by exposure to zinc oxide fume at the Occupational Safety and Health Administration Permissible Exposure Limit. The increase in IL-6 levels observed in the clinically responsive, and to a lesser extent, tolerant, states following zinc oxide inhalation is consistent with the dual role of IL-6 as a pyrogen and anti-inflammatory agent.
Collapse
|
62
|
Schlesinger RB, Snyder CA, Chen LC, Gorczynski JE, Ménache M. Clearance and translocation of aluminum oxide (alumina) from the lungs. Inhal Toxicol 2000; 12:927-39. [PMID: 10989369 DOI: 10.1080/08958370050137996] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Significant respiratory-tract exposure to insoluble aluminum compounds, such as alumina (aluminum oxide, Al(2)O(3)), can occur in occupational settings, yet little is known about the temporal pattern of pulmonary clearance of these materials from the lungs with repeated exposures, and potential subsequent translocation to other organs. This study evaluated the clearance pattern of alumina from the lungs of rats, and burdens in selected extrapulmonary organs (brain, bone, liver, spleen, kidney). Rats were instilled with alumina once weekly for 20 wk. Quantification of retention was performed by measuring aluminum burdens in the lungs and extrapulmonary organs during the exposure period, and then weekly for an additional 19 wk after the exposures ended. Lung burdens of aluminum were found to steadily increase during exposure. Clearance of the material following the end of the exposure regime was extremely slow; only approximately 9% of the amount in the lungs following the 20 weekly exposures was cleared by the end of the postexposure period. This study supports the concept of gradual accumulation and long-term retention of aluminum within the respiratory tract of individuals repeatedly exposed to alumina in occupational settings.
Collapse
|
63
|
Jeng SF, Yau KI, Liao HF, Chen LC, Chen PS. Prognostic factors for walking attainment in very low-birthweight preterm infants. Early Hum Dev 2000; 59:159-73. [PMID: 10996272 DOI: 10.1016/s0378-3782(00)00088-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The purpose of this study was to compare the age of walking attainment between very low-birthweight (VLBW) preterm infants and normal term infants, and to determine the variables that affect the walking attainment in VLBW infants. Ninety-six VLBW preterm infants and 82 normal term infants were prospectively followed to determine their age of walking attainment and to monitor gross motor development with sequential clinic visits at 6, 9, 12 and 18 months corrected age. Perinatal and sociodemographic data were collected through review of medical records. The VLBW infants were significantly older at attainment of walking (median 14 months) than the term infants (median 12 months) after correction for prematurity. By the age of 18 months, all term infants had attained walking ability; while 11% of VLBW infants were still unable to walk. Multivariate proportional hazards regression analysis revealed that low gestational age was significantly associated with late attainment of walking in VLBW infants. With the adjustment for gestational age, prolonged ventilation (or oxygen therapy) and severe retinopathy of prematurity were significant predictors of late walking attainment. Our findings indicate that VLBW preterm infants have an increased risk of delayed attainment of walking. Furthermore, the contribution of low gestational age to the delayed walking attainment in VLBW infants may occur via the plausible pathways of neonatal respiratory distress and severe retinopathy of prematurity.
Collapse
|
64
|
Connelly CA, Chen LC, Colquhoun SD. Metabolic activity of cultured rat brainstem, hippocampal and spinal cord slices. J Neurosci Methods 2000; 99:1-7. [PMID: 10936637 DOI: 10.1016/s0165-0270(00)00205-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The use of cultured brain slices has become an accepted technique for the ex vivo analysis of neural mechanisms, yet the viability of this preparation is not routinely measured. The tetrazolium dye 3-(4, 5-dimethlythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) is reduced by active mitochondria to an insoluble purple precipitate which accumulates within living cells and is easily visualized with bright field or phase contrast microscopy. In this study, the MTT assay was used to assess the viability of cultured brainstem, hippocampal and spinal cord slices (150-300 micrometer) from 0 to 22 day-old neonatal rats at post-explant time points ranging from 2 to 29 days. After 2 weeks, 180-300 micrometer cultured slices from 4-13 day old rats remained 90-100% viable. Those from 0-1 day old rats had similar viability but displayed peripheral tissue outgrowth. Slices from older 18-22 day rats were no longer viable after 10-14 days. After 4 weeks, the thicker (300 micrometer) slices of hippocampus and spinal cord retained 75-89% viability, in contrast to the 50-74% viability of the brainstem. Thinner brainstem and hippocampal slices (150-220 micrometer) slices were less than 50% viable at 4 weeks. Morphologic characteristics of the brain regions gradually degenerated over the 4-week culture period. Slice viability was markedly influenced by tissue thickness, donor age and brain region. Use of the MTT assay provides an inexpensive and expeditious means to assess a significant functional parameter of regional slice viability under variable conditions and enhances the feasibility of this preparation for functional studies, such as those concerned with genetic and protein expression within circumscribed areas of the brain.
Collapse
|
65
|
Wu TC, Chen YH, Chen JW, Chen LC, Lin SJ, Ding PY, Wang SP, Chang MS. Impaired forearm reactive hyperemia is related to late restenosis after coronary stenting. Am J Cardiol 2000; 85:1071-6. [PMID: 10781754 DOI: 10.1016/s0002-9149(00)00698-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To investigate whether systemic endothelial function on forearm resistance vessels is related to angiographic restenosis after coronary stenting, 47 men who underwent elective coronary stenting were divided into 2 groups according to the presence (n = 20) or absence (n = 27) of in-stent restenosis 6 months after the procedure. Another 19 risk factor-matched men with normal coronary angiograms served as the control group. Forearm blood flow was assessed by venous occlusive plethysmography. Basal forearm blood flow was similar between restenosis, nonrestenosis, and control groups (2.63 +/- 0.19, 2.58 +/- 0.14, and 3.23 +/- 0.13 ml/100 ml forearm tissue per minute, respectively). In all 3 groups, forearm blood flow increased significantly during reactive hyperemia (5.75 +/- 0.7, 11. 32 +/- 1.23, and 14.52 +/- 1.36 ml/100 ml forearm tissue per minute, p <0.05, respectively) and remained unchanged after sublingual administration of nitroglycerin. The percentage change of forearm blood flow during reactive hyperemia was significantly lower in the restenosis group (117.3 +/- 18.3%) than in the nonrestenosis group (354.2 +/- 46.5%, p <0.01). This difference was still present after sublingual nitroglycerin (37.6 +/- 21.2% vs 226.4 +/- 40.5%, p <0. 01). In contrast, percentage change of hyperemic forearm blood flow was significantly lower in patients with angina (117.5 +/- 49.5%) than in those without angina (290.1 +/- 37.4%, p <0.05) at follow-up. In all patients, the angiographic loss index was correlated negatively to the percentage change of hyperemic forearm blood flow (r = -0.33, p <0.01) and positively to the percentage change of forearm vascular resistance during reactive hyperemia (r = 0.33, p <0.01). In patients with angiographic restenosis after coronary stenting, forearm reactive hyperemia was more impaired compared with those without angiographic restenosis. Systemic endothelial dysfunction might be either a marker or one of the confounding factors in the development of late restenosis after coronary stenting.
Collapse
|
66
|
Gordon T, Nadziejko C, Chen LC, Schlesinger R. Effects of concentrated ambient particles in rats and hamsters: an exploratory study. Res Rep Health Eff Inst 2000:5-34; discussion 35-42. [PMID: 10897487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Considerable controversy surrounds the biological plausibility of adverse effects from exposure to ambient particulate matter (PM)*, chiefly because these adverse effects have been observed at particle mass concentrations below those that have been shown to produce effects in healthy animals and human volunteers in the laboratory. To address this research gap, we examined the potential for concentrated ambient PM to produce pulmonary and cardiovascular changes in compromise rodent models. Normal healthy and monocrotaline-treated rats received single or multiple exposures to concentrated ambient PM, and their responses were tested using functional, cellular, biochemical, and histological endpoints. Analyses determined that no changes in pulmonary function or structure occurred after exposure to concentrated ambient PM. Cardiac arrhythmias did not increase after PM exposure in normal or monocrotaline-treated rats. Increased atrial conduction time, accompanied by a decrease in the duration of the T wave portion of the electrocardiogram (ECG) waveform, was observed in PM-exposed monocrotaline-treated rats in one experiment. In addition, on several but not all exposure days, small yet statistically significant increases in heart rate and peripheral blood cell differential counts were observed in normal and monocrotaline-treated rats within 6 hours after exposure to concentrated ambient PM. The observed changes in cardiovascular parameters in rats returned to control values by 24 hours after exposure. In a hamster cardiomyopathy model, no adverse cardiac or pulmonary changes were detected after exposure to concentrated ambient PM. Thus, these studies found that cardiopulmonary effects could be produced in rats, but not in hamsters with cardiomyopathy, exposed to concentrated ambient PM. None of the changes occurred on every exposure day and none appeared to be life threatening. Thus, the cardiac changes may reflect changes in homeostasis that could affect individuals who are critically ill, and these findings do not resolve the biological plausibility of adverse health effects associated with ambient PM in epidemiologic studies.
Collapse
|
67
|
Chen LC, Chen YF, Yang LL, Chou MH, Lin MF. Drug utilization pattern of antiepileptic drugs and traditional Chinese medicines in a general hospital in Taiwan - a pharmaco-epidemiologic study. J Clin Pharm Ther 2000; 25:125-9. [PMID: 10849190 DOI: 10.1046/j.1365-2710.2000.00271.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Studies on antiepileptic drug utilization are important for the optimization of drug therapy and drug control. The present study was to evaluate the drug utilization pattern of standard antiepileptic drugs and traditional Chinese medicines (TCMs) in the treatment of different types of epilepsy in a general hospital in Taiwan. METHOD The epileptic patients under antiepileptic drug treatment at Veterans General Hospital-Taipei were considered in the analysis. Current diagnosis was obtained by the neurologist in charge of the patient. All patients were interviewed by standard questionnaire designed to provide specific information on the types of antiepileptic drugs and details of their use. The questionnaire also sought to determine whether TCMs were used, and whether patients were using TCMs in combination with hospital standard treatment. The results were analysed by descriptive statistics. RESULTS 729 patients with epilepsy definitely diagnosed were analysed in the study. 445 patients (61.04%) were prescribed with one antiepileptic drug. Combinations of two antiepileptic drugs were prescribed to 261 patients (35.80%), and combinations of three or more antiepileptic drugs to 23 patients (3.16%). A total of 1039 antiepileptic drugs was prescribed, corresponding to an average 1.42 drugs per patient. The most frequently prescribed antiepileptic drug was carbamazepine (56.93%), followed by phenytoin (31.96%), valproate (30.73%) and clonazepam (14.13%). Among the 729 epileptic patients, 83.68% used standard antiepileptic drugs alone, 16.32% used antiepileptic drugs in combination with TCMs. CONCLUSION Monotherapy is the type of therapy most frequently used in all types of seizures. The selection of antiepileptic drugs is based on efficacy for specific seizure types and epileptic syndromes. The most frequently prescribed antiepileptic drug was carbamazepine, followed by phenytoin, valproate and clonazepam. As some of the patients used TCMs for treatment of epilepsy even when scientific medicine has been provided, further studies on the possible interactions between TCMs and antiepileptic drugs are in progress.
Collapse
|
68
|
Huang JL, Lee WY, Chen LC, Kuo ML, Hsieh KH. Changes of serum levels of interleukin-2, intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1 and Th1 and Th2 cell in severe atopic dermatitis after intravenous immunoglobulin therapy. Ann Allergy Asthma Immunol 2000; 84:345-52. [PMID: 10752921 DOI: 10.1016/s1081-1206(10)62785-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To evaluate the effect of intravenous immunoglobulin (IVIG) in the treatment of severe intractable atopic dermatitis (AD) in children and to investigate the inflammatory markers used to measure their disease activity. MATERIALS AND METHODS Serum levels of interleukin-2 receptor (sIL-2R), intercellular adhesion molecule-1 (ICAM-1), endothelial leukocyte adhesion molecule (ELAM-1), and eosinophil cationic protein (ECP) were measured in five children with AD (group A) who had a mean age of 9.4 months (range 7 to 12 months) before and after IVIG therapy. Seven age-matched patients with similar severity of AD who only received topical corticosteroid therapy served as the control group (group B). Ten normal control serum samples were collected from well-baby clinic (group C). T helper 1 (Th1) was defined by IFN-gamma/CD4+ and Th2 by IL4/CD4+, using 3-colored flow cytometry. Clinical severity of AD was evaluated with the SCORAD index. Intravenous immunoglobulin (2 g/kg/dose) was administered monthly for a total of 3 doses. RESULTS The serum levels of ICAM-1, ELAM-1, and IL-2R in patients with AD were significantly higher than normal control infants. After IVIG therapy, the SCORAD index and the inflammatory markers (ICAM-1, ELAM-1, and ECP) in group A were significantly decreased (P = .01 for SCORAD index; .034, .043, and .03 for ICAM-1, ELAM-1 and ECP, respectively). The serum levels of ICAM-1, ELAM-1, ECP and IL-2R in group B did not show a significant reduction after 3 months of topical corticosteroid therapy. In comparison to normal healthy children, patients with AD had decreased Th2 cells (P = .009) and higher ratio of Th1/Th2 (P = .009) in peripheral blood mononuclear cells (PBMC). There was no significant difference of Th1, Th2 cells, and ratio of Th1/Th2 in PBMC before and after IVIG therapy in patients with AD. CONCLUSION Intravenous immunoglobulin can be safely and effectively given for the treatment of severe intractable AD. The determination of ICAM-1, ELAM-1, and ECP levels may be useful in monitoring disease activity of AD in childhood. The IVIG may play a role in treatment.
Collapse
|
69
|
Jeng SF, Yau KI, Chen LC, Hsiao SF. Alberta infant motor scale: reliability and validity when used on preterm infants in Taiwan. Phys Ther 2000; 80:168-78. [PMID: 10654063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND AND PURPOSE The goal of this study was to examine the reliability and validity of measurements obtained with the Alberta Infant Motor Scale (AIMS) for evaluation of preterm infants in Taiwan. SUBJECTS Two independent groups of preterm infants were used to investigate the reliability (n=45) and validity (n=41) for the AIMS. METHODS In the reliability study, the AIMS was administered to the infants by a physical therapist, and infant performance was videotaped. The performance was then rescored by the same therapist and by 2 other therapists to examine the intrarater and interrater reliability. In the validity study, the AIMS and the Bayley Motor Scale were administered to the infants at 6 and 12 months of age to examine criterion-related validity. RESULTS Intraclass correlation coefficients (ICCs) for intrarater and interrater reliability of measurements obtained with the AIMS were high (ICC=.97-.99). The AIMS scores correlated with the Bayley Motor Scale scores at 6 and 12 months (r=.78 and.90), although the AIMS scores at 6 months were only moderately predictive of the motor function at 12 months (r=.56). CONCLUSION AND DISCUSSION The results suggest that measurements obtained with the AIMS have acceptable reliability and concurrent validity but limited predictive value for evaluating preterm Taiwanese infants.
Collapse
|
70
|
Torres AM, Peterson KE, de Souza AC, Orav EJ, Hughes M, Chen LC. Association of diarrhoea and upper respiratory infections with weight and height gains in Bangladeshi children aged 5 to 11 years. Bull World Health Organ 2000; 78:1316-23. [PMID: 11143191 PMCID: PMC2560637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
INTRODUCTION The association between infection and growth delay is not well documented in school-age children in developing countries. We conducted a prospective cohort study to examine the association between infectious disease and weight and height gains among Bangladeshi children. METHODS A one-year follow-up study was performed to elucidate the determinants and consequences of physical growth of children under five years of age. The study included 135 households randomly selected from four villages in the Matlab area. RESULTS The most frequent infections were upper respiratory infections (mean = 4 episodes or 27 days per year) followed by non-dysenteric diarrhoea (mean = 2.3 episodes or 15 days per year) and dysentery (mean = 0.2 episodes or 2 days per year). The number of episodes and their duration decreased significantly with age. Over a 12-month period the mean weight gain was 1.3 kg and the mean increase in height was 2.9 cm. The total number of days when diarrhoea occurred was negatively associated with annual weight gain (regression coefficient beta = -7 g per day, P = 0.02), with adjustment for age, sex, energy and protein intake, and household land ownership. The incidence of diarrhoeal disease was significantly associated with weight gain in intermediate models but only marginally associated with it in the final multivariate model (P = 0.08). Neither the incidence nor the duration of upper respiratory infections was associated with weight gain. Height gain was not significantly associated with the duration or incidence of either category of illness. Diarrhoea was a significant correlate of retarded weight gain among children above preschool age, whereas upper respiratory infections were not. DISCUSSION Diarrhoeal morbidity slowed growth in children well beyond the weaning age, suggesting that increased attention should be given to the study of the continuous impact of diarrhoea in children aged over 5 years. An understanding of the determinants of growth in school-age children in developing countries would maximize the health and developmental outcomes that are the target of international child survival strategies at younger ages.
Collapse
|
71
|
Thorpe DS, Edith Chan AW, Binnie A, Chen LC, Robinson A, Spoonamore J, Rodwell D, Wade S, Wilson S, Ackerman-Berrier M, Yeoman H, Walle S, Wu Q, Wertman KF. Efficient discovery of inhibitory ligands for diverse targets from a small combinatorial chemical library of chimeric molecules. Biochem Biophys Res Commun 1999; 266:62-5. [PMID: 10581165 DOI: 10.1006/bbrc.1999.1775] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Living systems are mainly composed and regulated by compounds in four biochemical classes and their polymers-nucleotides, carbohydrates, lipids, and amino acids. Early combinatorial chemistry libraries consisted of peptides. The present report describes the general bioactivity and biophysical properties of a combinatorial chemical library that used glyco, nucleotidyl, and lipid building blocks. The resulting chimeric combinatorial library of 361 compounds had a confirmed cumulative hit rate of 0.16%, which is 8-fold higher than a commonly claimed industrial benchmark of 0. 02%. It produced 7 structurally confirmed hits for a third of 12 proprietary drug discovery projects, and these comprised a variety of molecular targets. Diversity analyses demonstrated that despite the small number of compounds, a wider range of diversity space was covered by this library of biochemical chimeras than by a branched tripeptide library of the same size and similar generic formula.
Collapse
|
72
|
Chen LC, Lee MH, Chou MH, Lin MF, Yang LL. Pharmacokinetic study of paeoniflorin in mice after oral administration of Paeoniae radix extract. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 735:33-40. [PMID: 10630888 DOI: 10.1016/s0378-4347(99)00408-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Quantification of paeoniflorin, the principal bioactive component of Paeoniae radix, in mice plasma following oral administration of Paeoniae radix extract was achieved by using a simple and rapid high-performance liquid chromatographic method. The calibration curve for paeoniflorin was linear (r2 = 0.998) over the concentration range 10-200 ng/ml. The coefficients of variation of intra- and inter-day assays were 15.04, 7.31, 6.14, 6.55, 6.63% and 12.71, 6.07, 3.61, 5.51, 4.52% at concentrations of 10, 60, 100, 160, 200 ng/ml, respectively. The recoveries of paeoniflorin from mice plasma were found to be 74.49, 76.83, 80.38 and 80.56% for concentrations of 30, 80, 120 and 160 ng/ml, respectively. The plasma concentration-time curves were fitted with mean terminal half-lives (t(1/2)) of 94.16 min.
Collapse
|
73
|
McManus MF, Chen LC, Vallejo I, Vallejo M. Astroglial differentiation of cortical precursor cells triggered by activation of the cAMP-dependent signaling pathway. J Neurosci 1999; 19:9004-15. [PMID: 10516318 PMCID: PMC6782746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
In the developing brain, differentiation of neural precursors into neurons or glial cells occurs in response to neurotrophic factors acting on the cell surface. Intracellular signaling mechanisms that relay information to initiate differentiative responses of neural precursor cells are poorly understood. To investigate whether stimulation of the cAMP-dependent signaling pathway participates in differentiative responses of cells in the developing CNS, we performed experiments using both conditionally immortalized neural precursor cells (RC2.E10 cells) and primary cultures of cells from developing rat cortex. Initially, we determined that RC2.E10 cells retain phenotypic features of neural precursors after inactivation of the immortalizing oncogene, a temperature-sensitive mutant of the simian virus 40 large-T antigen (SV40T). We found that, once SV40T is inactivated, RC2.E10 cells cease to divide and die. However, RC2. E10 cells can proliferate in the presence of basic fibroblast growth factor. In addition, they express nestin, a marker of neural precursor cells. Both RC2.E10 cells and primary cortical precursor cells undergo astroglial differentiation in response to cAMP stimulation by treatment with 8-bromo-cAMP. In both cases, cAMP-induced astrocyte differentiation is characterized by morphological changes, stimulation of glial fibrillary acidic protein expression, downregulation of nestin expression, and decreased proliferation. No increases in the expression of neuronal or oligodendrocytic markers were observed. Our results support the notion that the developing CNS contains neural precursor cells with the capacity of undergoing astrocyte differentiation in response to increased intracellular cAMP concentrations.
Collapse
|
74
|
Chen LC, Kepka-Lenhart D, Wright TM, Morris SM. Salicylate-enhanced activation of transcription factors induced by interferon-gamma. Biochem J 1999; 342 Pt 3:503-7. [PMID: 10477259 PMCID: PMC1220489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Salicylate enhanced the interferon-gamma-dependent activation of two transcription factors in a murine macrophage cell line: signal transducer and activator of transcription (STAT)1 and interferon-gamma-responsive factor 1. Salicylate alone did not activate these transcription factors. This enhancement was reflected by increased DNA-binding activities and was the consequence of prolonged tyrosine phosphorylation of these transcription factors following interferon-gamma treatment. However, salicylate did not directly inhibit protein-tyrosine phosphatase activity in nuclear extracts of interferon-gamma-treated cells. The enhanced activation of STAT1 resulted in increased induction of mRNA encoding interferon regulatory factor-1. These results not only demonstrate that aspirin and its metabolite salicylate may have pro-inflammatory as well as anti-inflammatory effects but also raise the possibility that new cellular targets may be identified for modulating the Janus kinase-STAT signalling pathway.
Collapse
|
75
|
Chen LC, Huang JL. Intractable wheezing and swallowing problem in an infant: report of one case. ACTA PAEDIATRICA TAIWANICA = TAIWAN ER KE YI XUE HUI ZA ZHI 1999; 40:341-3. [PMID: 10910546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
A 9-month-old female infant with intractable wheezing and frequent aspiration pneumonia was poor response to the usual treatment for respiratory disease. The barium swallow test revealed barium aspirating into trachea directly. Because of the high-risk nature for aspiration in the swallowing disorder infant, a nasogastric tube feeding therapy was prescribed. Fortunately, her symptoms were greatly reduced. One month later, the clinical and roentgenographic findings strongly support a causal relationship between swallowing problem and wheezing. Therefore, swallowing problem should be considered when a young infant has refractory wheezing, even when there is no developmental problem.
Collapse
|