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Pan-Chyr Yang

Publications and source records attributed to Pan-Chyr Yang.

At least 109 records · Page 6Linked to original sources
PubMed2004

Detection of SARS-associated coronavirus in throat wash and saliva in early diagnosis.

The severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is thought to be transmitted primarily through dispersal of droplets, but little is known about the load of SARS-CoV in oral droplets. We examined oral specimens, including throat wash and saliva, and found large amounts of SARS-CoV RNA in both throat wash (9.58 x 10(2) to 5.93 x 10(6) copies/mL) and saliva (7.08 x 10(3) to 6.38 x 10(8) copies/mL) from all specimens of 17 consecutive probable SARS case-patients, supporting the possibility of transmission through oral droplets. Immunofluorescence study showed replication of SARS-CoV in the cells derived from throat wash, demonstrating the possibility of developing a convenient antigen detection assay. This finding, with the high detection rate a median of 4 days after disease onset and before the development of lung lesions in four patients, suggests that throat wash and saliva should be included in sample collection guidelines for SARS diagnosis.

Adult↗
PubMed2004

Comparison of histidine-tryptophan-ketoglutarate and Euro-Collins solutions for lung preservation using the minipig in situ warm ischemia model.

BACKGROUND AND PURPOSE: Reperfusion injury remains a common problem in lung transplantation. This study compared the effect of lung preservation with histidine-tryptophan-ketoglutarate (HTK), a relatively low potassium solution, and Euro-Collins (EC) solution by using a minipig in situ model of warm ischemia. METHODS: The left lungs of 5 minipigs were selectively flushed with EC solution. HTK was used for flush perfusion in 6 other minipigs. After 60 minutes of warm ischemia, the left lungs were reperfused. Hemodynamics, aerodynamics, and arterial blood gas were measured after the blood flow and ventilation of the contralateral lungs were temporally blocked. Bronchoalveolar lavage fluid (BALF) analysis, lung wet-to-dry weight ratio (W/D ratio) and histological analysis were done before perfusion (right lung) and 2 hours after reperfusion (left lung). RESULTS: This in situ model of warm ischemia induced significantly increased pulmonary arterial pressure, pulmonary vascular resistance, BALF albumin contents and neutrophil counts, histological injury score, lung W/D ratio and tissue myeloperoxidase assay. The HTK perfusion group had a significantly lower degree of lung injury than the EC perfusion group. CONCLUSIONS: Lung preservation with HTK solution resulted in better lung function after reperfusion than preservation by EC solution in this minipig model.

Animals↗
PubMed2004

Using senior residents as standardized patients for evaluating basic clinical skills of medical students.

BACKGROUND AND PURPOSE: The use of standardized patients (SPs) is a powerful method for performance evaluation in medical education. It has gained increasing popularity in teaching and evaluation of clinical skills of medical students in the last decade. Maintaining an active and effective SP program requires a tremendous amount of financial and manpower investment, which may be difficult for many medical schools to provide. This study investigated the feasibility and effectiveness of using senior residents as SPs (SRSPs) to alleviate the financial and manpower burdens of an SP program. METHODS: A total of 112 fifth year medical students and 26 third year senior residents from a university hospital participated in this research in 2000. Students at the end of a 9-week rotating clerkship in internal medicine formed groups of 7 members. Senior residents took multiple roles as case developers, SPs, teachers, and evaluators. Test and recess stations were integrated, and sequential individual and group discussion with SRSPs was used to provide feedback immediately after the completion of the examination. Students were given a test report including scores and written narrative feedback. Semi-constructive questionnaires were used for opinion survey from students as well as the SRSPs. RESULTS: All SRSPs demonstrated their ability to function in multiple roles and regarded the SRSP experience as helpful to improve this ability. Most SRSPs (89%) considered the experience beneficial in improving their clinical teaching skills. Ninety percent of SRSPs thought that a case should be portrayed for no more than 4 hours in order to maintain the consistency and accuracy. Seventy two percent of medical students reported that SRSPs' status as teachers did not interfere with their performance, 68% reported being able to treat SRSPs as real patients, and 96% reported that the evaluation was helpful to their professional development. CONCLUSIONS: An SRSP program is feasible, practical, and easy to establish. It can provide benefits to both students and senior residents with clinical training responsibilities, and serve as an alternative method for performance evaluation of students in medical schools with limited resources.

Clinical Clerkship↗
PubMed2004

Drug resistance pattern of Mycobacterium tuberculosis in a university hospital in Taiwan, 1998-2002.

BACKGROUND AND PURPOSE: During 1998-2002, most specialized tuberculosis (TB) hospitals in Taiwan were closed; as a result, more TB patients are being managed in general hospital settings. This study investigated the prevalence, patterns and risk factors of drug-resistant Mycobacterium tuberculosis at a university hospital in the 5 years after decentralization of the TB administrative and clinical control infrastructure which occurred during the implementation of the national health insurance system in Taiwan. METHODS: A total of 1411 initial isolates of M. tuberculosis from specimens collected during January 1998 through December 2002 were tested for drug susceptibility of first-line anti-TB drugs using the agar proportional method. RESULTS: The numbers of newly diagnosed culture-positive TB patients increased from 139 in 1998 to 380 in 2002. The drug resistance pattern of M. tuberculosis among these isolates was as follows: 268 (19.0%) strains were resistant to isoniazid, 86 (6.1%) to rifampin, 221 (15.7%) to ethambutol, 141 (10.0%) to streptomycin, and 430 (30.5%) to 1 of these 4 drugs. Multidrug resistance (MDR), i.e., resistance to at least rifampin and isoniazid, was observed in 72 isolates (5.1%). Of the 1411 patients, isolates from patients with age < 65 years had a higher multiple drug resistance rate than those from patients with age > or = 65 years (57/781, 7.3% vs 15/630, 2.4%; p < 0.001). In the analysis of risk factors for MDR, patients with MDR isolates had a significantly higher incidence of previous TB history, anti-TB therapy, longer duration of symptoms, cavitary lesions in chest X-ray, and mortality. CONCLUSION: A dramatic increase in cases of TB among patients treated at this university hospital was seen after the decentralization of the TB control infrastructure in Taiwan. The prevalence of drug resistance in isolates from culture-positive TB patients was 30.5% and the prevalence of MDR was 5.1%.

Adult↗
PubMed2003

Effect of frying-meat emission particulate on 17beta-estradiol 2- and 4-hydroxylation in human lung adenocarcinoma CL5 cells.

The effect of airborne frying-meat emission particulate (FMEP) on metabolism of 17beta-estradiol (E(2)) to potentially toxic catechol estrogens 2- and 4-hydroxyestradiol (2- and 4-OH-E(2)) was determined using human lung adenocarcinoma CL5 cells treated with organic extracts of beef FMEP. E(2) was incubated with microsomes prepared from untreated CL5 cells or cells treated with 200 microg/ml FMEP extract for 6 h. E(2) metabolites formed were analyzed by high-performance liquid chromatography (HPLC). The results revealed that treatment with FMEP produced three-and twofold increases of 2- and 4-hydroxylation of E(2), respectively. Monooxygenase activity and immunoblot analyses showed that FMEP markedly induced microsomal 7-ethoxyresorufin O-deethylase (EROD) activity and cytochrome P-450 (CYP) IAI and CYPIBI protein levels. Similar increases in E(2) hydroxylation, EROD activity, and CYP protein levels were observed with HepG2 human hepatoma and MCF-7 human breast cancer cells treated with FMEP or 1 microM dibenz[a,h]anthracene. Cotreatment of CL5 cells with FMEP extract and 2 microM alpha-naphthoflavone, an arylhydrocarbon receptor antagonist, blocked the inductive effects of FMEP on E(2) hydroxylation and EROD activity. Additions of 0.01, 0.1, or 1 microM alpha-naphthoflavone, a CYP inhibitor, to microsomes produced concentration-dependent decreases in E(2) 2-hydroxylation and EROD activity of CL5 cells induced by dibenz[a,h]anthracene. The present finding demonstrates that FMEP can increase formation of 2-OH-E(2) and 4-OH-E(2) by human lung cells, and induction of CYP1A1 and CYP1B1 is a potential mechanism underlying increased E(2) metabolism. The toxicological significance of FMEP and estrogen interaction warrants further investigation.

Adenocarcinoma↗
PubMed2003

Posterior mediastinal arteriovenous malformation with atypical color Doppler sonographic findings.

An arteriovenous malformation (AVM) is an anomaly of capillary development that results in a direct connection between branches of an artery and veins, with no intervening capillary network. A definite diagnosis of AVM is usually made with angiography. We report the case of a posterior mediastinal AVM found on routine sonography in a 64-year-old woman with neglected hypertension and severe back pain. Color Doppler imaging showed 2 adjoined vascular structures without a typical mosaic-like flow pattern, and spectral Doppler analysis showed low-resistance flow and arteriovenous shunting in 2 adjoined vascular structures. The diagnosis was subsequently confirmed by angiography. Because disastrous bleeding could result if needle biopsy were performed inadvertently in the case of a suspected mediastinal AVM, we suggest that color Doppler sonography be attempted if there is an adequate acoustic window.

Arteriovenous Malformations↗
PubMed2003

Diagnostic value of negative expiratory pressure for airway hyperreactivity.

STUDY OBJECTIVES: To examine the value of negative expiratory pressure (NEP) in the assessment of methacholine bronchoprovocation testing (BPT). DESIGN: Prospective, observational study. SETTING: Pulmonary function laboratory in a university hospital. PARTICIPANTS: Fifty-nine patients with chronic cough referred from outpatient clinics for methacholine BPT. METHODS: Each subject inhaled successive doubling concentrations of methacholine (from 0.049 to 25 mg/mL) until the FEV(1) decreased for > 20% or the maximum concentration of methacholine was inhaled. NEP was measured in the sitting position during tidal breathing before and after methacholine BPT. The FEV(1) and forced oscillation airway resistance (Rrs) and interrupter airway resistance (Rint) were also obtained simultaneously. A positive BPT result was defined as a fall in FEV(1) > or = 20%. RESULT: At baseline, only five patients had expiratory flow limitation as demonstrated by NEP (EFL-N). There were 39 patients with positive BPT results, and the other 20 patients had negative results. Among the BPT-positive patients, only 13 patients (33.3%) had EFL-N after methacholine challenge. The sensitivity indexes (absolute change/SD) of FEV(1), NEP, Rrs, and Rint were 16.0 +/- 9.6%, 1.1 +/- 1.6%, 3.8 +/- 4.5%, and 5.89 +/- 4.4% (mean +/- SD), respectively. The percentage changes in FEV(1) in BPT-positive patients correlated with the percentage changes in Rrs (r = 0.419, p = 0.008) and only marginally with the percentage changes in Rint (r = 0.307, p = 0.058), but not with the changes in EFL-N (r = 0.048, p = 0.77). CONCLUSION: These data suggest that NEP at sitting position is not sensitive in the assessment of methacholine bronchoprovocation as compared to FEV(1) and airway resistance measurements.

Adult↗
PubMed2003

Collapsin response mediator protein-1: a novel invasion-suppressor gene.

Numerous genetic changes are associated with metastasis of cancer cells. Previously, we used microarray to identify that collapsin response mediator protein-1 (CRMP-1) was involved in cancer invasion and metastasis. We further characterized that CRMP-1 was a novel invasion-suppression gene. Members of the CRMP gene family are intracellular phosphoproteins involved in the mediation of semaphorin induced F-actin depolymerization and growth cone collapse. The precise mechanism by which CRMP-I inhibits invasion is not yet clear. However, CRMP-1 transfected cells had fewer filopodia and less Matrigel-invasion abilities. A low expression of CRMP-I mRNA in lung cancer tissue was significantly associated with advanced disease, lymph node metastasis, early post-operative relapse, and shorter survival. In this article, we reviewed the functions of CRMPs and semaphorins and analyzed the structure and motifs of CRMP-1 by bioinformatics. As such, we hoped to shed further light on the mechanism by which CRMP-1 suppresses the invasion of cancer cells.

Endothelial Growth Factors↗
PubMed2003

Usefulness of computed tomography-guided transthoracic small-bore coaxial core biopsy in the presence of a pneumothorax.

Transthoracic needle biopsy (TNB) is usually avoided in the presence of pneumothorax. The authors performed computed tomography (CT)-guided transthoracic core biopsy in the presence of pneumothorax in 13 patients (4.9%) selected from 265 patients who received CT-guided TNB over 4 years. These iatrogenic pneumothoraces were induced by previous ultrasound (US)-guided TNB (n = 5), transbronchial lung biopsy (n = 4), and CT-guided biopsy (n = 4). The time interval between previous thoracic intervention and CT-guided TNB ranged from 0 hours to 9 days after transbronchial lung biopsy (average, 4 days). A diagnostic core biopsy was performed in 12 of the 13 patients. Seven lesions proved to be malignant and five were benign. Failure of CT-guided transthoracic core biopsy occurred in a single patient with a previous US-guided biopsy within 24 hours. This patients demonstrated a progressively enlarging pneumothorax and was treated with air aspiration with CT guidance. A successful second biopsy was performed 7 days later after full expansion of the lung. There were no complications related to the procedures. The authors' experience suggests that CT-guided transthoracic core biopsy using small-bore coaxial technique can be safely performed with high-diagnostic yield in patients with stable iatrogenic pneumothorax.

Adult↗
PubMed2003

Ultrasound in the diagnosis and management of pleural disease.

The authors summarize the current applications of chest ultrasonography in the diagnosis and management of various pleural diseases. Ultrasound has been proved to be valuable for the evaluation of a wide variety of chest diseases, particularly when the pleural cavity is involved. Chest ultrasound can supplement other imaging modalities of the chest and guides a variety of diagnostic and therapeutic procedures. Pleural effusion, pleural thickening, pleural tumors, tumor extension into the pleura and even the chest wall, pleuritis, and pneumothorax can be detected easily and accurately with chest ultrasound. Many ultrasound features and signs of these diseases have been well characterized and widely applied in clinical practice. Under real-time ultrasound guidance the success rates of invasive procedures on pleural diseases increase significantly whereas the risks are greatly reduced. The advantages of low-cost, bedside availability and no radiation exposure have made ultrasound an indispensable diagnostic tool in modern pulmonary medicine.

Humans↗
PubMed2003

Changes of heart rate variability during ventilator weaning.

STUDY OBJECTIVES: Despite the recognition that ventilator weaning is associated with a change in autonomic nervous system activity, there has not been any report concerning the change of heart rate variability (HRV), a reliable method to detect autonomic nervous system activity, in patients during weaning. The aim of this study was to investigate the change of autonomic nervous system activity during ventilator weaning by HRV analysis. DESIGN: Prospective study. SETTING: A 16-bed medical ICU of a tertiary university hospital. PATIENTS: Twenty-four patients receiving mechanical ventilation were included. Twelve patients with successful extubation after a spontaneous breathing trial (SBT) [T-piece trial] were classified as the success group; otherwise, the patients were placed in the failure group. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Variables, including the total power (TP), and the high-frequency (HF) and low-frequency (LF) components of HRV, were measured in three phases: assist/control mandatory ventilation, pressure support ventilation (PSV), and SBT. While shifting from PSV to SBT, the HRV components decreased significantly in the failure group (TP, p = 0.025; LF, p = 0.007; HF, p = 0.031), but not in the success group. CONCLUSIONS: By HRV analysis, reduced HRV and vagal withdrawal of the autonomic nervous system activity are the main changes in patients with weaning failure.

Aged↗
PubMed2003

Microbiologic characteristics, serologic responses, and clinical manifestations in severe acute respiratory syndrome, Taiwan.

The genome of one Taiwanese severe acute respiratory syndrome-associated coronavirus (SARS-CoV) strain (TW1) was 29,729 nt in length. Viral RNA may persist for some time in patients who seroconvert, and some patients may lack an antibody response (immunoglobulin G) to SARS-CoV <21 days after illness onset. An upsurge of antibody response was associated with the aggravation of respiratory failure.

Adult↗
PubMed2003

Up-regulation of tumor interleukin-8 expression by infiltrating macrophages: its correlation with tumor angiogenesis and patient survival in non-small cell lung cancer.

PURPOSE: To evaluate the interaction between tumor-infiltrating macrophages and cancer cells and its effect on the expression of a potent angiogenic factor, interleukin-8 (IL-8), tumor angiogenesis, and patient outcome in non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: We measured tumor IL-8 mRNA expression (by real-time quantitative reverse transcription-PCR), intratumor microvessel counts, and tumor-infiltrating macrophage density (by immunohistochemical staining) in 35 NSCLC surgical specimens and correlated with the patient's clinical outcome. We then investigated the interaction between macrophages (cell line THP-1) and six different human cancer cell lines (four NSCLCs, one osteosarcoma, and one hepatoma) and its effect on IL-8 mRNA expression using a macrophage/cancer cell coculture system, IL-8 mRNA expression in lung cancer cells, and macrophages being measured separately after coculture in the presence or absence of six anti-inflammatory agents, i.e., pentoxifylline, aspirin, indomethacin, dexamethasone, celecoxib (a selective cyclooxygenase-2 inhibitor), and pyrrolidine dithiocarbamate, a specific nuclear factor kappaB (NF-kappaB) inhibitor. NF-kappaB transcriptional activity and protein levels were measured by reporter gene assay and Western blot. RESULTS: The tumor-infiltrating macrophage density correlated significantly and positively with tumor IL-8 mRNA expression and intratumor microvessel counts and significantly and negatively with patient survival. In addition, after cell-cell interaction in cancer cell:macrophage cocultures, marked IL-8 mRNA expression was induced in lung cancer cells (approximately 270-fold) and, to a lesser degree, in macrophages (4.5-fold). The increase in IL-8 mRNA expression correlated with the in vitro metastatic potential of the cancer cells. All six anti-inflammatory agents suppressed induction of IL-8 mRNA expression in lung cancer cells by >90%, four (pentoxifylline, celecoxib, pyrrolidine dithiocarbamate, and dexamethasone) having a dose-dependent effect. NF-kappaB transcriptional regulation and protein levels were simultaneously increased in the nuclei of cancer cells in macrophage/cancer cell cocultures, this effect also being suppressed by all six anti-inflammatory agents. CONCLUSIONS: The interaction between infiltrating macrophages and cancer cells up-regulates IL-8 mRNA expression, especially in the cancer cells; this may contribute greatly to the increased tumor angiogenesis and adverse outcome in NSCLC patients with a high density of tumor-infiltrating macrophages. Anti-inflammatory agents can suppress the induction of IL-8 mRNA expression seen in lung cancer cells after coculture with macrophages, and this suppression is mediated, in part, through the NF-kappaB pathway.

Carcinoma, Non-Small-Cell Lung↗
PubMed2003

Diffuse alveolar damage associated with ticlopidine use: a case report.

Ticlopidine-induced lung disease is rare. A 52-year-old man with acute myocardial infarction developed respiratory distress 2 days after receiving ticlopidine for coronary artery stenting. The dosage of ticlopidine was 500 mg orally followed by maintenance of 250 mg twice daily. Chest radiography revealed bilateral haziness predominantly over upper lung fields. He did not respond to treatment for suspected cardiogenic lung edema and mechanical ventilation was instituted. Open lung biopsy documented diffuse alveolar damage. After discontinuing ticlopidine and treatment with systemic corticosteroid, his pulmonary condition improved gradually. Within 2 weeks, the patient was successfully weaned from the ventilator. Although rare, diffuse alveolar damage is a potential side effect of ticlopidine treatment and should be included in the differential diagnoses of heart failure patients taking ticlopidine who respond poorly to optimal therapy.

Humans↗