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Biomedical subjects

S J Chen

Publications and source records attributed to S J Chen.

At least 55 records · Page 3Linked to original sources
PubMed2001

The assessment of the proximal left pulmonary artery by transesophageal echocardiography and computed tomography in neonates and infants: a case series.

IMPLICATIONS: Transesophageal echocardiography (TEE) is often used during surgical repair of congenital heart disease. In our case series of 256 newborns and infants, we found that a left paracarinal view of TEE could visualize the proximal left pulmonary artery, a frequent blind spot for TEE, in most patients, except in a few cases with anatomic variations of the esophagus in the right lateral to the vertebra.

Cardiac Surgical Procedures↗
PubMed2001

Pulsatile ocular blood flow in asymmetric exudative age related macular degeneration.

BACKGROUND/AIMS: Decreased perfusion or increased vascular resistance of the choroidal vessels had been proposed as the vascular pathogenesis for age related macular degeneration (AMD). This study planned to answer the question whether pulsatile ocular blood flow (POBF) was different in patients with asymmetric exudative AMD between eyes with drusen, choroidal neovascularisation (CNV), or disciform scar. METHODS: 37 patients with asymmetric exudative AMD were enrolled in this observational case series study. POBF were measured in both eyes of each subject. Eyes with high myopia, anisometropia, recent laser treatment, and glaucoma were excluded. RESULTS: After adjusting for ocular perfusion pressure, intraocular pressure, and pulse rate, multivariate regression analysis with generalised estimating equation showed POBF was significantly higher in eyes with CNV (1217 (SD 476) microl/min) than the contralateral eyes with drusen (1028 (385) microl/min) (p = 0.024). Eyes with disciform scar had lower POBF than the contralateral eyes with drusen (999 (262) microl/min and 1278 (341) microl/min, respectively, p<0.001). There was no significant correlation between the POBF and the lesion size of the CNV. CONCLUSION: The POBF in eyes with drusen was lower than their fellow eyes with CNV, but higher than their fellow eyes with disciform scar. This finding suggests that haemodynamic differences between fellow eyes in individuals are relevant to the development of CNV and the formation of disciform scar. Further studies on the follow up patients might shed light on the pathogenesis of exudative AMD.

Aged↗
PubMed2001

Preoperative diagnosis by electron beam computed tomography and perioperative management of primary tracheal anomalies in tetralogy of Fallot.

PURPOSE: To investigate the usefulness of electron beam computed tomography (EBCT) in the preoperative detection and perioperative management of insidious concomitant primary tracheobronchial anomalies in patients with tetralogy of Fallot (TF). METHODS: From July 1995 to October 1999, 88 children (38 girls, 50 boys) with TF were enrolled in this study. EBCT examinations provided information needed to plan management. The final diagnoses of airway abnormalities were correlated with the findings of bronchoscopy in five patients and confirmed during surgery. RESULTS: Fourteen (16%) of the 88 patients had associated primary tracheobronchial anomalies. Nine patients had tracheal bronchi, which were combined with tracheobronchial stenosis in two patients and with tracheal stenosis in one patient. Two patients had tracheal diverticulum, which was combined with lower tracheal stenosis in one patient. Two patients had congenital tracheal stenosis. Tracheomalasia was found in one patient. Three patients with ventilation difficulties died postoperatively. Special attention was given to the care of the diseased airways perioperatively, and the remaining 11 patients had a smooth course of hospitalization and discharge. CONCLUSIONS: Our results show that EBCT provides good delineation of both cardiac and tracheobronchial anomalies and suggest that it should be used perioperatively to detect associated airway anomalies in TF, to facilitate the design of an appropriate ventilation care strategy.

Adolescent↗
PubMed2001

Combined atrial and arterial switch operations for congenitally corrected transposition.

Conventional repair of congenitally corrected transposition of the great arteries (CCTGA) is directed at eliminating the associated defects and leaves the right ventricle in a systemic position. The long-term outcome of this procedure may involve deterioration of right ventricular function with tricuspid regurgitation and failure of the conduction system. We describe two consecutive patients with CCTGA, one of whom had apicocaval juxtaposition. The patients were aged 19 and 16 months, respectively, and both underwent a combination of atrial and arterial switch. These are the first two reported cases of successful completion of this type of operation in Taiwan. Our review of previously reported cases suggested that no significant difference exists in the outcome of patients with this condition who undergo either arterial switch or Rastelli-type repair plus atrial redirection. However, reported patients who underwent anatomic repair had lower early mortality, late mortality, and incidence of complete heart block than those who underwent conventional repair. The present two cases and our review of the literature suggest that, among patients with apicocaval juxtaposition, 1) Mustard operation is optimal for patients with small atrial volume; 2) one-and-one-half ventricular repair may be helpful to the outcome, especially when treatment is combined with Rastelli-type repair; and 3) excellent access to the ventricular septal defect through the tricuspid valve is afforded via a left atriotomy. From the present two cases and our review of the literature, we conclude that anatomic repair is superior to conventional repair of CCTGA in terms of protection against dysfunction and failure of the anatomic right ventricle, tricuspid valve, and conduction system. Long-term follow-up is mandatory.

Cardiac Surgical Procedures↗
PubMed2001

Langerhans' cell histiocytosis presenting with a para-aortic lesion and heart failure.

Langerhans' cell histiocytosis (LCH) is an uncommon disease with variable manifestations. We report a case of LCH with the unusual initial presentations of chest pain and progressive heart failure in a 5-year-old boy. Chest radiography revealed a wide mediastinum with cardiomegaly. Electrocardiography showed first-degree atrioventricular block and an inverted T wave over V4-V6. Echocardiography, computed tomography, and magnetic resonance imaging of the chest all showed an infiltrating lesion that enveloped the entire heart, great vessels, and coronary arteries. Pathologic examination of the biopsy specimen revealed LCH. Chemotherapy, which included prednisolone, vincristine, methotrexate, and 6-mercaptopurine, had only a minimal effect on the tumor. After the addition of etoposide, the lesion decreased in size, and the symptoms and signs of heart failure and chest pain were ameliorated.

Aortic Diseases↗
PubMed2001

Modified arterial switch operation by sharing the common wall between the great arteries.

BACKGROUND: Suprapulmonary stenosis and coronary arterial obstruction still remain as problems after an arterial switch operation (ASO). We used a modified ASO applying the common wall and in situ transfer techniques to improve the current procedure. METHODS: From October 1996 to December 1997, 11 babies aged 6 days to 3 months with transposition of the great arteries underwent a modified ASO which included sharing the common wall between the great arteries until above the anterior neoaortic suture-line for coronary and pulmonary artery reconstruction. Coronary arteries were of usual type in three cases, juxtacommissural origin in five, and a high takeoff in one; all were redirected almost in situ. RESULTS: There was no early death (< 30 d), coronary or bleeding problems. One late death occurred after a repeat surgery for suprapulmonary stenosis. This was caused by upward stretching of the left pulmonary artery, which was placed above the high left-sided neoaortic anastomosis for in situ transfer of the high takeoff coronary arteries. Intraluminal growth of the adventitia also contributed to suprapulmonary stenosis, which decreased significantly when the common wall adventitia was cleaned in the last two cases we operated on. Ten patients were doing well at follow-up (30.9 +/- 5.2 mo). CONCLUSIONS: This modified ASO by common wall and in situ transfer might avoid coronary kinking and lessen the chance of postoperative bleeding. To avoid suprapulmonary stenosis, common wall adventitia inside the pulmonary pathway should be cleaned, and the left and right pulmonary arteries should also be kept in situ as possible as in coronary redirection.

Humans↗
PubMed2001

Valveless outflow reconstruction using autologous tissue as a posterior wall for pulmonary atresia with ventricular septal defect.

BACKGROUND AND PURPOSE: Reoperation is inevitable for some patients with pulmonary atresia who receive a heterograft or homograft in a primary Rastelli operation. Nonetheless, the need for reoperation in patients with classic Fallot's tetralogy who have undergone total correction with a transannular patch is unusual. We sought to change pulmonary atresia into Fallot's tetralogy and used a transannular patch instead of the conventional Rastelli operation. PATIENTS AND METHODS: Valveless outflow direct reconstruction was performed on 10 consecutive patients with pulmonary atresia and ventricular septal defect between August 1997 and 1999. Patient ages ranged from 1.3 to 11.5 years. A Blalock-Taussig shunt was previously constructed in four of these patients and a central shunt was constructed in five. The major aortopulmonary collateral arteries were occluded in one patient by repeated coil embolization after the central shunt. The strategy was to connect the right ventriculotomy with the pulmonary arteries directly, even if there was a gap with a long atretic cord. In patients with a previous central shunt covered with a Gore-Tex membrane, the reactive visceral pericardium over the in situ tissue (the left atrium, right ventricle, or aorta) was used as the autologous posterior wall. Thus, only autologous, fresh pericardium without a valve was used to cover the anterior part of the right ventricular outflow tract, as in the repair of classic Fallot's tetralogy with a transannular patch. RESULTS: There was no mortality, and the postoperative central venous pressure was low in all patients. No gradient was noted across the right ventricular outflow tract. Follow-up echocardiography revealed a competent tricuspid valve with mild pulmonary regurgitation in all patients. CONCLUSIONS: The results of this study suggest that valveless outflow direct reconstruction provides adequate pulmonary circulation without hypertension in pulmonary atresia patients with a ventricular septal defect if the tricuspid valve is competent.

Child, Preschool↗
PubMed2001

[Neocartilage of predetermined shapes].

OBJECTIVE: To study chondrogenesis of calcium alginate-chondrocytes predetermined shapes. METHODS: Chondrocytes isolated from ears of rabbit by type II collagenase digestion, and then were mixed with 1.5% solidium alginate solution. The suspension was gelled to create three spatial shapes as triangle, circle and quadrilateral by immersed into 2.5% CaCl2 for 90 minutes, and then was implanted into the subcutaneous pocket on the dorsum of the rabbit. Samples were harvested at 6 and 12 weeks after implantation. RESULTS: Gross examination of excised specimens at 6 and 12 weeks after implantation revealed the presence of new cartilage of approximately the same dimensions as the original construct. Histologic evaluation using hematoxylin and eosin stains confirmed the presence of cartilage nodules at 6 weeks after implantation. After 12 weeks, mature cartilage was observed and histologic analysis confirmed the presence of well formed cartilaginous matrix. CONCLUSION: Predetermined shapes neocartilage can be regenerated using calcium alginate as a carrier of chondrocytes in the bodies of immune animals.

Alginates↗
PubMed2001

Pulmonary function during exercise in obese children.

BACKGROUND: Obesity imposes additional stress to ventilation during exercise. The purpose of this study is to evaluate the pulmonary function changes with graded exercise and the habitual level of physical activity in obese children. METHODS: This study recruited 42 obese and 10 normal students, aged 11, from Tamsui Elementary School. Measurements of cardiopulmonary fitness were recorded after a jump rope test. Height, weight and body mass indices were determined before testing. RESULTS: A significant correlation was found between triceps skin-fold thickness and the body mass index (BMI; r = 0.65, p < 0.05). Blood systolic pressure significantly increased in the obese subjects in their post-exercise test. There was no significant difference between the obese and the non-obese groups in any of the lung function test measurements. Forced expiratory volume in the first second (FEV1), peak expiratory flow rate (PEFR) and forced vital capacity (FVC) were similar in both groups. CONCLUSIONS: Physiologic responses are not sufficiently different from between the obese subjects and the non-obese children. We should pay more attention to fostering confidence in the obese child exercise.

Child, Preschool↗
PubMed2001

Preoperative diagnosis and localization of aldosterone-producing adenoma by adrenal venous sampling after administration of metoclopramide.

BACKGROUND AND PURPOSE: Adrenal venous sampling is the most reliable test to distinguish aldosterone-producing adenoma (APA) from idiopathic hyperaldosteronism (IHA). The diagnostic accuracy can be improved by administration of adrenocorticotropin to minimize pulsatile secretion of aldosterone. Metoclopramide (MCP), a dopamine antagonist, can increase aldosterone secretion promptly without affecting cortisol secretion. This study investigated the diagnostic accuracy of adrenal venous sampling after MCP injection for the preoperative diagnosis and localization of APA. METHODS: Prospective diagnosis and adrenalectomy was based on adrenal venous sampling in 23 patients with a diagnosis of primary aldosteronism. Plasma aldosterone concentrations from adrenal veins and the inferior vena cava were measured before and 30 minutes after intravenous administration of 10 mg MCP. The ratio of bilateral adrenal venous aldosterone concentrations after MCP was used for diagnosis as follows: a ratio greater than 5 indicated APA, less than 3 indicated IHA, and 3-5 indicated an intermediate diagnosis. RESULTS: Catheterization of the right adrenal vein was unsuccessful in three patients. Twelve of 13 patients with an aldosterone ratio greater than 5 after MCP underwent unilateral adrenalectomy, and APA was confirmed in 11 of these patients. One patient with an intermediate diagnosis also had surgically confirmed APA. Six patients had a ratio less than 3. Before MCP administration, 10 of 13 patients with APA had a ratio greater than 5, and three patients had a ratio between 3 and 5; one patient with IHA had a ratio greater than 5. MCP improved the diagnosis of APA to an accuracy of 92% (12/13). Correct diagnosis of APA based on computerized tomography (CT) was 85% (11/13). There was discordance between the findings of adrenal venous sampling and CT in four of 20 patients. CONCLUSIONS: Administration of MCP to stimulate aldosterone secretion during adrenal venous sampling can improve the accuracy of differential diagnosis between APA and IHA.

Adenoma↗
PubMed2001

Retinopathy of prematurity: screening, incidence and risk factors analysis.

BACKGROUND: The sequela of retinopathy of prematurity (ROP) is an important cause of infant blindness. This study was designed to screen the high-risk premature infants and investigate the incidence and risk factors associated with the development of ROP. METHODS: From October 1997 to October 1998, all premature infants with birth body weight (BBW) less than 2000 gm or gestational age (GA) less than 36 weeks were enrolled and underwent ophthalmologic examination at 4 to 6 weeks of age at Taipei Veterans General Hospital. The perinatal variables were analyzed to evaluate their correlation with the development of ROP. RESULTS: In totally 108 premature infants, the incidence for development of ROP was 25% (27 in 108 patients). The threshold ROP occurred in 15 eyes (7%). The average BBW and GA (1267+/-341 gm and 29.7+/-2.7 weeks) were significantly lower in ROP group than in the non-ROP group (1703+/-368 gm and 32.3+/-2.2 weeks). The artificial ventilation for more than 5 days, chronic lung disease and periventricular leukomalacia were significant risk factors associated with highest rate of ROP. The respiratory distress syndrome, intraventricular hemorrhage, congenital heart disease and sepsis were significant risk factors accompanied by moderate rate of ROP. CONCLUSION: Low birth body weight and young gestational age are the most important risk factors in the development of ROP. The analysis of risk factors will be helpful in understanding and prediction of ROP formation in high-risk neonates. The timely clinical screening retina examination of high-risk premature infants is important to prevent the development of advanced ROP.

Female↗
PubMed2001

[Researches on morphology and anatomy of root system of Dendrobium nobile Lindl].

OBJECTIVE: To understand the morphological and anatomical characteristics of Dendrobium nobile so as to provide scientific basis for its domestication and cultivation. METHOD: The root's morphological development and interior structure were investigated. RESULT AND CONCLUSION: Dendrobium has peculiar structure which determines that this plant requires a growing environment with high water and air ventilation properties.

Dendrobium↗
PubMed2001

[Studies on anamorph of Cordyceps sinensis (Berk) from Naqu Tibet].

OBJECTIVE: To isolate and determine the strain of anamorph of Cordyceps sinensis collected from Naqu Tibet. METHOD: Isolating the strains of anamorph of Cordyceps sinensis collected from Baqing Shuoxian, Biru Counties by means of the ascope, tissue, ossified larva and body liquid. RESULT: Same strain of anamorph of Cordyceps sinensis was obtained with 4 different methods. CONCLUSION: The strain of Hirsutella sinensis is the anamorph of C. sinensis from Naqu Tibet.

Animals↗
PubMed2001

[Studies on Paecilomyces muscardine of Cordyceps sinensis host insect].

OBJECTIVE: To Clarify the cause of the disease of Cordyceps sinensis host insect Paecilomyces muscardine. METHOD: Separately observing eggs, larvals, pupals, adults and their circumstances causing diseases in every stage. Adopting separately Hemolymph, bodies of dead insects and conidiospores; separating and culturing them, them observing and identifying the inoculum. Inoculating healthy larvals from the purely separated and cultured plants of inoculum. RESULT AND CONCLUSION: The original inoculum of the disease is Paecilongces frinoues, which may often be found in the period of larvals and seldom found in the period of pupals but never in that of adults and eggs. The main symptom of larval is dullness and weakness. But the typical Symptom is a layer of a kind of white power of conidiospore on the surface of the dead body which comes into being later stage.

Animals↗
PubMed2000

Hyperpolarization contributes to vascular hyporeactivity in rats with lipopolysaccharide-induced endotoxic shock.

We have examined the role of membrane hyperpolarization in mediating vascular hyporeactivity induced by bacterial lipopolysaccharide (LPS) in endothelial-denuded strips of rat thoracic aorta ex vivo. The injection of rats with LPS caused a significant fall of blood pressure and a severe vascular hyporeactivity to norepinephrine. The membrane potential recording showed that endotoxemia caused a hyperpolarization when compared to the control. This hyperpolarization was fully restored by methylene blue (MB; 10 microM) and partially reversed by Nomega-nitro-L-arginine methyl ester (L-NAME; 0.3 mM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 microM), tetraethylammonium (TEA; 10 mM), charybdotoxin (CTX; 0.1 microM), or glibenclamide (GB; 10 microM), however, this hyperpolarization was not significantly affected by apamin (0.1 microM), 4-aminopyridine (4-AP; 1 mM), or Ba2+ (50 microM). In addition, the basal tension of the tissues obtained from endotoxemic rats was enhanced by the following order: MB > or = ODQ > TEA > or = L-NAME > or = CTX > GB; whereas apamin, 4-AP or Ba2+ had no significant effects on these tissues. In contrast, none of these inhibitors had significant effects on the membrane potential or the basal tension in control tissues. Our electrophysiological results further confirmed previous studies showing that in addition to nitric oxide, the large conductance Ca2+-activated K+-channels and ATP-sensitive K+-channels are, most likely, responsible for endotoxin-mediated hyporeactivity to vasoconstrictor agents in vascular smooth muscle.

Animals↗
PubMed2000

Genomic organization of the JEM-1 (BLZF1) gene on human chromosome 1q24: molecular cloning and analysis of its promoter region.

The Jem-1 (JEM-1, HGMW-approved symbol BLZF1) gene mapping to human chromosome 1q24 codes for a ubiquitously expressed 3-kb mRNA, translated in a 45-kDa nuclear protein. Recent studies have shown a deficient expression of this gene in acute promyelocytic leukemia (APL). However, treatment with retinoids was able to upregulate JEM-1 mRNA in maturing NB4 leukemia cells. Here, we report the characterization of the structural organization of JEM-1. By hybridization screening of a human genomic library derived from blood mononuclear cells, five overlapping genomic DNA clones were isolated. These clones extend over 34 kb of the human genome and comprise the complete JEM-1 gene and a 4-kb 5'flanking region. Determination of the exon-intron structure of Jem-1 revealed seven exons whose junctions with introns exhibited typical splice sequences. A shorter transcript (Jem-1s, 1.3 kb) generated by exon 3 extension and polyadenylation was identified. Its translation generated a 23-kDa protein that exhibited a cytoplasmic localization. 5'RACE-PCR identified a major transcription start site (TSS) located at 403 nt upstream of the ATG. Computer analysis of the 1. 8-kb 5'flanking region showed that it lacks a TATA box, Inr motifs or DPE motifs, but it contains a typical CCAAT box located 95 bp upstream of the TSS. Sequencing also revealed potential cis-acting elements for multiple transcription regulators including Sp1, GATA, C/EBP, AP-1, and Pu1. No retinoic acid receptor elements or retinoic X receptor elements were detected. This 1.8-kb DNA sequence showed a strong constitutive promoter activity determined by a luciferase-reporter gene assay in transiently transfected HeLa cells. Retinoids further increased luciferase expression 2.7-fold. We demonstrated that the 1-kb distal sequence contains yet unidentified elements reducing constitutive transcription. Thus, the maximal constitutive promoter activity was assigned to a -432 + 101 region overlapping the TSS. These data support the idea of a constitutive expression of JEM-1, but a negative regulation in APL released by retinoids.

5' Untranslated Regions↗
PubMed2000

TAS+(Z)-Me3CNSN- and TAS+(E)-Me3SiNSN-: does the anion-cation interaction influence the configuration?

TAS+ salts (TAS = (Me2N)3S) of the sulfur diimide anions Me3XNSN- (X = C (1a), Si (1b)) were prepared by Si-N bond cleavage from the corresponding sulfur diimides Me3XNSNSiMe3 and TAS-fluoride ((Me2N)3S+Me3SiF2-) and characterized by X-ray crystallography and multinuclear NMR spectroscopy. According to the experimentally determined bond lengths and theoretical calculations, the Me3XNSN- anions are best described as thiazylamides Me3X-N-S identical to N rather than sulfur diimides Me3X-N=S=N. In agreement with the calculated and experimentally determined structures of the isoelectronic thionylimides RNSO, 1a adopts the Z-configuration, which is electronically favored due to anomeric effects. The electronically disfavored E-configuration of 1b in the solid state can be explained by weak anion-cation interaction.

Journal Article↗