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S J Chen

Publications and source records attributed to S J Chen.

At least 91 records · Page 5Linked to original sources

Arsenic trioxide-induced apoptosis and differentiation are associated respectively with mitochondrial transmembrane potential collapse and retinoic acid signaling pathways in acute promyelocytic leukemia.

Recent studies showed that arsenic trioxide (As2O3) could induce apoptosis and partial differentiation of leukemic promyelocytes. Here, we addressed the possible mechanisms underlying these two different effects. 1.0 microM As2O3-induced apoptosis was associated with condensation of the mitochondrial matrix, disruption of mitochondrial transmembrane potentials (DeltaPsim) and activation of caspase-3 in acute promyelocytic leukemia (APL) cells regardless of their sensitivity to all-trans retinoic acid (ATRA). All these effects were inhibited by dithiothreitol (DTT) and enhanced by buthionine sulfoximine (BSO). Furthermore, BSO could also render HL60 and U937 cells, which had the higher cellular catalase activity, sensitive to As2O3-induced apoptosis. Surprisingly, 1.0 microM As2O3 did not induce the DeltaPsim collapse and apoptosis, while 0.1 microM As2O3 induced partial differentiation of fresh BM cells from a de novo APL patient. In this study, we also showed that 0.2 mM DTT did not block low-dose As2O3-induced NB4 cell differentiation, and 0. 10.5 microM As2O3 did not induce differentiation of ATRA-resistant NB4-derived sublines, which were confirmed by cytomorphology, expression of CD11b, CD33 and CD14 as well as NBT reduction. Another interesting finding was that 0.10.5 microM As2O3 could also induce differentiation-related changes in ATRA-sensitive HL60 cells. However, the differentiation-inducing effect could not be seen in ATRA-resistant HL60 sublines with RARalpha mutation. Moreover, low-dose As2O3 and ATRA yielded similar gene expression profiles in APL cells. These results encouraged us to hypothesize that As2O3 induces APL cell differentiation through direct or indirect activation of retinoic acid receptor-related signaling pathway(s), while DeltaPsim collapse is the common mechanism of As2O3-induced apoptosis.

Antineoplastic Agents↗

Gene expression in CD34(+) cells from normal bone marrow and leukemic origins.

INTRODUCTION: To address the molecular regulation of hematopoiesis and the complex mechanism in leukemogenesis, we established the first catalogs of genes expressed in normal bone marrow and leukemia CD34(+) cells. MATERIALS AND METHODS: CD34(+) cell cDNA libraries were constructed using mRNA from adult bone marrow and from a case of acute myeloid leukemia-M5 transformed from myelodysplastic syndrome (MDS-AML). Expressed sequence tags (ESTs) and full-length cDNAs were generated by sequencing and were annotated using bioinformatic tools. RESULTS: From a total of 4142 ESTs obtained from normal bone marrow, 3424 meaningful tags were integrated into 1630 clusters, representing 622 known genes, 522 dbEST entries and 486 novel sequences. Out of 5382 ESTs from MDS-AML, 1985 clusters were produced based on the analysis of 4321 useful ESTs, including 711 known genes, 657 known ESTs and 617 novel sequences. Among 251 transcripts found in both bone marrow and MDS-AML EST datasets and those present in only one dataset, 58 showed statistically significant differences in EST copy numbers between the two tissues (P<0.05). Twenty putative full-length cDNAs for novel genes were also cloned from the MDS-AML library. CONCLUSION: The distinct gene expression patterns in MDS-AML-CD34(+) cells as compared to normal control cells may contribute to the development and/or maintenance of the malignant phenotypes of leukemia cells.

Adult↗

Bioadhesives for intraocular use.

BACKGROUND/PURPOSE: A safe, effective adhesive could be useful in the management of retinal holes or tears and selected complicated retinal detachments, as well as for attaching a small electronic device (retinal prosthesis) to the retina. In this study, we examined nine commercially available compounds for their suitability as intraocular adhesives. METHODS: The following materials were studied: commercial fibrin sealant, autologous fibrin, Cell-Tak, three photocurable glues, and three different polyethylene glycol hydrogels. An electronic strain gauge measured the adherence forces between different glues and the retina. The stability of hydrogels at body temperature and the impermeability of the hydrogel adhesive to dextran blue were examined. Long-term biocompatibility testing of the most promising glues in terms of adhesive force, consistency, and short-term safety (hydrogels) were done in rabbits. Funduscopy, electroretinogram, and histology of the retina were performed. RESULTS: Hydrogels had 2 to 39 times more adhesive force (measured in mN) than the other glues tested. They liquefied at body temperature after 3 days to a few months. Hydrogels were impermeable to dextran blue. One type of hydrogel proved to be nontoxic to the retina. CONCLUSIONS: Hydrogels proved to be superior for intraocular use in terms of consistency, adhesiveness, stability, impermeability, and safety.

Adhesiveness↗

Terbutaline prevents circulatory failure and mitigates mortality in rodents with endotoxemia.

Septic shock is characterized by a decrease in systemic vascular resistance. Nevertheless, regional increases in vascular resistance can occur that may predispose mammals to organ dysfunction, including the acute respiratory distress syndrome. In the host infected by endotoxin (lipopolysaccharide, LPS), the expression and release of proinflammatory tumor necrosis factor-alpha (TNFalpha) rapidly increases, and this cytokine production is regulated by agents elevating cyclic AMP. In this report, we present evidence that terbutaline, a beta2-agonist, inhibits TNFalpha production and enhances interleukin-10 (IL-10) release in the anesthetized rat treated with LPS. In addition, an overproduction of nitric oxide (NO, examined by its metabolites nitrite/nitrate) by inducible NO synthase (iNOS, examined by western blot analysis) is attenuated by pretreatment of LPS rats with terbutaline. Overall, pretreatment of rats with terbutaline attenuates the delayed hypotension and prevents vascular hyporeactivity to norepinephrine. In addition, pretreatment of mice with terbutaline also improves the survival in a model of severe endotoxemia. The infiltration of polymorphonuclear neutrophils into organs (e.g., lung and liver) from the surviving LPS mice treated with terbutaline was reduced almost to that seen in the normal controls. These findings suggest that the inhibition of TNFalpha and NO (via iNOS) production as well as the increment of IL-10 production contribute to the beneficial effect of terbutaline in animals with endotoxic shock.

Acetylcholine↗

Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells.

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58-752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon-intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3' UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

Alternative Splicing↗

3-D reconstruction of coronary arterial tree to optimize angiographic visualization.

Due to vessel overlap and foreshortening, multiple projections are necessary to adequately evaluate the coronary tree with arteriography. Catheter-based interventions can only be optimally performed when these visualization problems are successfully solved. The traditional method provides multiple selected views in which overlap and foreshortening are subjectively minimized based on two dimensional (2-D) projections. A pair of images acquired from routine angiographic study at arbitrary orientation using a single-plane imaging system were chosen for three-dimensional (3-D) reconstruction. After the arterial segment of interest (e.g., a single coronary stenosis or bifurcation lesion) was selected, a set of gantry angulations minimizing segment foreshortening was calculated. Multiple computer-generated projection images with minimized segment foreshortening were then used to choose views with minimal overlapped vessels relative to the segment of interest. The optimized views could then be utilized to guide subsequent angiographic acquisition and interpretation. Over 800 cases of coronary arterial trees have been reconstructed, in which more than 40 cases were performed in room during cardiac catheterization. The accuracy of 3-D length measurement was confirmed to be within an average root-mean-square (rms) 3.5% error using eight different pairs of angiograms of an intracoronary guidewire of 105-mm length with eight radiopaque markers of 15-mm interdistance. The accuracy of similarity between the additional computer-generated projections versus the actual acquired views was demonstrated with the average rms errors of 3.09 mm and 3.13 mm in 20 LCA and 20 RCA cases, respectively. The projections of the reconstructed patient-specific 3-D coronary tree model can be utilized for planning optimal clinical views: minimal overlap and foreshortening. The assessment of lesion length and diameter narrowing can be optimized in both interventional cases and studies of disease progression and regression.

Cardiac Catheterization↗

Hypoxia reduces atrial natriuretic peptide clearance receptor gene expression in ANP knockout mice.

We tested the hypotheses that hypoxic exposure is associated with exacerbated pulmonary hypertension and right ventricular (RV) enlargement, reduced atrial natriuretic peptide (ANP) clearance receptor (NPR-C) expression, and enhanced B-type natriuretic peptide (BNP) expression in the absence of ANP. Male wild-type [ANP(+/+)], heterozygous [ANP(+/-)], and homozygous [ANP(-/-)] mice were studied after a 5-wk hypoxic exposure (10% O(2)). Hypoxia increased RV ANP mRNA and plasma ANP levels only in ANP(+/+) and ANP(+/-) mice. Hypoxia-induced increases in RV pressure were significantly greater in ANP(-/-) than in ANP(+/+) or ANP(+/-) mice (104 +/- 17 vs. 45 +/- 10 and 63 +/- 7%, respectively) as were increases in RV mass (38 +/- 4 vs. 26 +/- 5 and 29 +/- 4%, respectively). NPR-C mRNA levels were greatly reduced in the kidney, lung, and brain by hypoxia in all three genotypes. RV BNP mRNA and lung and kidney cGMP levels were increased in hypoxic mice. These findings indicate that disrupted ANP expression worsens hypoxic pulmonary hypertension and RV enlargement but does not alter hypoxia-induced decreases in NPR-C and suggest that compensatory increases in BNP expression occur in the absence of ANP.

Animals↗

Evaluation of serum interleukin-8 as a marker of disease activity in acute asthma in children.

Cytokine-mediated interactions among the inflammatory cells may play a role in the pathogenesis of bronchial asthma. Interleukin-8 (IL-8) is a major cytokine in the recruitment of neutrophils to the area of inflammation. Serum IL-8 is a marker of disease activity and treatment efficacy in bronchial asthma. To understand the role of IL-8 in disease activity in acute asthma, changes in serum concentrations of IL-8 elaborated by activated eosinophil before and after prednisolone therapy with clinical improvement were determined in the present study. Circulating levels of IL-8 in 15 normal control subjects and in sera from 20 allergic asthmatic children with acute exacerbation and in stable condition were determined by using commercially available assay kits. The mean concentration of serum IL-8 was statistically significantly higher in asthmatic children with acute exacerbation (63.62 +/- 11.41 pg/mL) and in stable asthmatics (64.22 +/- 10.31 pg/mL) compared to the control group subjects (50.40 +/- 30.70 pg/mL; p < 0.01). However, the difference was not statistically significant between the acute exacerbation and stable asthmatics groups (p > 0.05). Serum IL-8 is a poor indicator of disease activity in acute asthma; therefore, monitoring by serum IL-8 concentration is of limited value. The clinical value of serum IL-8 as a marker of disease activity remains to be established.

Acute Disease↗

Fibrinofibrous pericarditis mimicking a pericardial tumor.

Primary pericardial disease is rare in children. The clinical features usually reflect limited venous return and cardiac output. Tuberculous pericarditis is the leading cause of pericardial disease in developing nations. A definitive diagnosis in children is frequently difficult and the manifestations are protean. We report a 10-month-old girl with fibrinofibrous pericarditis that manifested as constrictive pericarditis with prolonged fever, hepatomegaly, edema, and poor appetite. Echocardiography showed a solid mass that originated from the thickened pericardium and compressed the whole heart. In contrast, computed tomography revealed pericardial thickening with fluid collection. The symptoms and signs dramatically improved after surgical pericardiectomy. Pathologic analysis confirmed the diagnosis of tuberculous fibrinofibrous pericarditis. The patient received a 1-year course of antituberculosis therapy and has remained symptom free for 2 years. We suggest that a discrepancy between echocardiography and computed tomography (CT) findings might indicate a diagnosis of fibrinofibrous pericarditis.

Diagnosis, Differential↗

Diffuse toxoplasmic retinochoroiditis as the initial manifestation of acquired immunodeficiency syndrome.

Toxoplasmic retinochoroiditis is an important opportunistic retinal infection in human immunodeficiency virus (HIV)-infected patients. It may present as diffuse necrotizing retinochoroiditis instead of a focal lesion and may be the initial manifestation of HIV infection. A 50-year-old heterosexual man presented with blurred vision in his left eye of 3 months' duration. Fundus examination revealed diffuse necrotizing retinochoroiditis, mainly at the posterior pole, with marked vitritis in the left eye. Serologic studies and aqueous fluid antibody titers indicated recent toxoplasmic infection. Positive enzyme immunoassays (EIA) and Western blot tests proved HIV infection. The retinochoroiditis and vitritis improved after an antitoxoplasmic regimen with trimethoprim-sulfamethoxazole (TMP-SMX). Nonetheless, toxoplasmic encephalitis developed 6 months after the onset of ocular toxoplasmosis and responded well to TMP-SMX. This is the first case of toxoplasmic retinochoroiditis as the initial manifestation of AIDS reported in Taiwan. We suggest that Toxoplasma infection should be included in the differential diagnosis of diffuse necrotizing retinochoroiditis and vitritis. We also recommend that adults with newly diagnosed ocular toxoplasmosis be screened for HIV infection.

AIDS-Related Opportunistic Infections↗

Intravenous injection of an adenovirus encoding hepatocyte growth factor results in liver growth and has a protective effect against apoptosis.

BACKGROUND: Hepatocyte growth factor/scatter factor (HGF/SF) is a pleiotropic cytokine with mitogenic, motogenic and morphogenic effects for a wide variety of cells. Previous studies have reported that the in vivo infusion in normal, untreated mice of recombinant HGF results in low levels of DNA synthesis and liver proliferation. In this study, we examined whether liver regeneration could be obtained by the in vivo injection of a recombinant adenoviral vector encoding human HGF (Ad.CMV.rhHGF) in normal, intact mice. MATERIALS AND METHODS: C57BL/6 mice were infused intravenously with doses increasing from 1 to 4 x 1011 particles of the recombinant human HGF (rhHGF) adenoviral vector or with a control virus encoding Escherichia coli beta-galactosidase (Ad.CMV.lacZ). At day 5, mice were sacrificed and evaluated for the presence of hepatocyte mitogenesis and liver regeneration (5-bromo-2'-deoxyuridine (BrdU) assays and liver weight determination) and for the presence of liver damage (serum alanine amino-transferase (ALT) measurements and TUNEL assays). RESULTS: In vivo administration of rhHGF stimulated DNA synthesis of hepatocytes and liver weight in a dose-dependent fashion. The maximal effect was seen after the infusion of 3 x 1011 particles which resulted at day 5 in >130% increase in relative liver mass with little cytopathic effect. In contrast, administration of the lacZ adenoviral vector caused little hepatocyte replication, but induced high levels of serum ALT (approximately 3 times higher than the rhHGF vector) and significant apoptotic cell death. CONCLUSIONS: This study shows that a single injection of Ad.CMV.rhHGF alone is able to induce in vivo and in a very short period of time, robust DNA synthesis and liver proliferation in normal mice without liver injury or partial hepatectomy. This recombinant adenoviral vector has a lower toxicity than the control lacZ adenovirus. This suggests that HGF may have a protective effect against adenovirus-induced pathology.

Adenoviridae↗

First successful ventricular septation of double inlet left ventricle in Taiwan.

Patients with a double inlet ventricle may undergo surgery using a modified Fontan procedure, in which the pulmonary ventricle is not utilized, or a procedure in which a pulmonary ventricle is created through ventricular septation. Ventricular septation is preferred to the Fontan procedure because there is better cardiorespiratory response to exercise after surgery. A 4-year-old girl with Holmes heart underwent ventricular septation on 12 May 1998. Pulmonary artery banding had been performed at 3 months of age and rebanding 16 days later. She was well and continued to grow. Ultrafast computed tomography and cardiac catheterization prior to surgery showed a double inlet left ventricle (LV) connected to a right posterior aorta with a right-sided rudimentary right ventricle that drained to the left anterior pulmonary trunk. Left ventricular end diastolic volume was 218% of normal and the ejection fraction was 79%. After debanding and enlargement of the bulboventricular foramen, a 3 x 4-cm composite patch of equine pericardium and Dacron velour was used to septate the ventricle, with transmural stitching at the apical portion. The patient survived the operation with complete atrioventricular block, and was extubated 6 days later. A permanent pacemaker was implanted 1 month later. One year after surgery, she was doing well. Echocardiography revealed paradoxical septal motion with good ventricular function. This is the first report of successful ventricular septation of a double inlet left ventricle performed in Taiwan.

Cardiac Surgical Procedures↗

Population-based study on prevalence and risk factors of age-related cataracts in Peitou, Taiwan.

BACKGROUND: Age-related cataracts are the main cause of blindness throughout the world. Nonetheless, population-based data on the epidemiology of age-related cataracts among Taiwanese populations are not readily available. This study was conducted to estimate the prevalence of age-related cataracts and to determine the relationships of age, gender, blood pressure, diabetes and smoking to the risks of age-related cataracts in an urban Taiwanese population. METHODS: The study was part of a population-based survey of eye diseases among residents aged 50 years or older in Peitou Precinct, Taipei, Taiwan. Of the 2,700 eligible persons, 2,038 (75.5%) underwent a standard evaluation protocol including dilated slit-lamp examination, a questionnaire of medical and ophthalmic histories and blood pressure measurement. RESULTS: Among the participants, 1,040 were diagnosed with age-related cataracts. The prevalence was 51.0% (95% confidence interval, 48.9%-53.2%). Nuclear opacity was the most prevalent type (718/1,040; 35.2%) of cataracts, followed by posterior subcapsular opacity (311/1,040; 15.3%) and cortical opacity (163/1,040; 7.8%). An increased risk of age-related cataracts was associated with female gender (p = 0.002). When a single type of lens opacity was considered, diabetes was significantly associated with a posterior subcapsular cataract (p = 0.022). Overall, older women with diabetes and relatively lower diastolic blood pressure were more likely to have age-related cataracts. CONCLUSIONS: The study provided the first prevalence data on age-related cataracts in an urban Taiwanese population and highlighted the relationships of age, gender, blood pressure and diabetes to the frequency and type of age-related cataracts. The results can assist in the design and implementation of intervention programs to reduce the prevalence of age-related cataracts.

Age Factors↗

Evaluation of different blood culture media in neonatal sepsis.

Blood drawn from neonatal patients is available in only limited amounts for blood cultures. The BACTEC Pediatrics (PEDS) Plus aerobic nonradiometric blood culture bottle was designed to aid the diagnosis of pediatric bacteremia. To assess the value of PEDS Plus blood culture medium for neonatal patients, we prospectively compared the PEDS Plus blood culture medium with the standard BACTEC aerobic medium (NR6A). From January to December 1999, 192 pairs of PEDS Plus and NR6A blood culture bottles were collected by the pediatric microbiology laboratory of Taipei Veterans General Hospital. Seventeen (8.85%) isolates were considered to be clinically significant microorganisms. Isolation rate of the PEDS Plus culture bottles was significantly higher than that of the NR6A culture bottles (p < 0.001). Six isolates were detected at least 1 day earlier by using the PEDS Plus culture bottles (p < 0.001). Among those patients who were under antibiotic therapy, the PEDS Plus culture bottle showed more significant growth than the NR6A culture bottle (p < 0.001). After weighing their benefits, we suggest substituting PEDS Plus bottles for NR6A bottles when culturing blood from neonatal patients or from those who are receiving antibiotic therapy.

Bacteremia↗

Pseudophakic Penicillium endophthalmitis.

A healthy 76-year-old woman complained of redness and a painful sensation in her right eye after cataract surgery 5 months previously. The eye was treated with topical corticosteroid and ciprofloxacin, and a soft exudative mass on the nasal lower iris was noted later. Fungal endophthalmitis was suspected and a repeat aqueous culture grew Penicillium spp. After treatment with topical natamycin and an intracameral injection of amphotericin B, the endophthalmitis was cured. We describe the disease course and management and discuss topical corticosteroids as a possible risk factor for increasing the dissemination of Penicillium infection. This was a unique case of successful therapy resulting in the cure of Penicillium endophthalmitis in an immunocompetent patient.

Aged↗

Statistics in ophthalmic research: two eyes, one eye or the mean?

BACKGROUND: Ophthalmic data, while different among individuals, are usually similar between fellow eyes of the same individual. This study was designed to illustrate alternative approaches to account for the correlation between fellow eyes. This is important for making inferences using data from both eyes. METHODS: With the use of a real data set from a population-based study, we described the distribution of intraocular pressure (IOP) by estimating the mean and standard deviation (SD) and evaluated the potential risk factors of higher IOP based on the regression method. The units of observation studied were of both eyes, right eye only, left eye only, the eyes with higher IOP and the mean value of both eyes. Furthermore, the generalized estimating equation (GEE) method was used to account for the correlation between fellow eyes in the regression analysis. Results and inferences from the different approaches were compared. RESULTS: The analysis included all the eyes, providing the largest sample size and unbiased estimates of the mean and SDs. There were some discrepancies among different approaches in the regression analysis. The GEE method simultaneously evaluated the effects of both eyes, and increased precision and enhanced inferences. CONCLUSIONS: Inconsistent results among different ophthalmic studies result from variations in not only study design and courses but also statistical methods. Making the best use of appropriate statistical techniques, which account for between eye correlation, provides valid statistical inferences.

Blood Pressure↗

A study of injectable tissue-engineered autologous cartilage.

OBJECTIVE: To test the effectiveness of the new techniques of tissue-engineered cartilage. METHODS: Chondrocytes were harvested through type II collagenase digestion from the auricle of New Zealand rabbits. The cells were mixed with alginate to generate chondrocytes/alginate composites with final cellular density of 50 x 10(6) per mL. Calcium chloride was used as the cross-linking agent to gel the aqueous alginate solution. The chondrocytes/alginate composites were injected into the dorsal subcutaneous tissue of New Zealand rabbits through autologous cells grafts. The specimens were observed during cartilage formation at 4, 8, and 12 weeks after injection. RESULTS: Prior to harvesting, chondrocytes/alginate composites were easily visualized under the dorsal skin of animals. The appearance of experimental specimens was similar to that of native cartilage in gross morphology. Using a standard hematoxylin and eosin stain, the histologic features of all experimental specimens demonstrated new cartilage formation. With a Masson's trichrome and safranin O stain, the presence of collagen and glycosaminoglycan (GAG) was observed at 8 and 12 weeks. CONCLUSION: This study demonstrated that polymerization of alginate hydrogel can be controlled to allow injection of chondrocytes that produce new autologous cartilage at subcutaneous dorsal site of rabbits. Injectable tissue-engineered autologous cartilage is promising for potential use in oral and maxillofacial surgery.

Alginates↗

[Distinguish of the original fungi of the Chinese traditional medicine, hongqu with gas chromatography fuzzy clustering analytical method].

OBJECTIVE: To establish a gas chromatography fuzzy clustering analytical method for classifying of origin fungi of the Chinese traditional medicine, Hongqu. METHODS: The volatile and nonvolatile components of 7 ordinary species of Monascus including M. aurantiacus Lee, etc. were analyzed by capillary gas chromatog raphy using FID: Inlet temperature 280 degrees C, detector temperature 280 degrees C, temperature program 130 degrees C, 5 min-->10 degrees C.min-1-->200 degrees C, 10 min. RESULTS: In the peak number and contents of volatile and nonvolatile components of Monascus exist obviously differences through which Monascus can be distinguished easily by the main fingerprint peaks within 20 minutes. CONCLUSION: The capillary gas chromatography fuzzy clustering analytical method is useful to the identification of Monascus fungi.

Chromatography, Gas↗