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C I Chang

Publications and source records attributed to C I Chang.

At least 37 records · Page 2Linked to original sources
PubMed1998

An automatic diagnostic system for CT liver image classification.

Computed tomography (CT) images have been widely used for liver disease diagnosis. Designing and developing computer-assisted image processing techniques to help doctors improve their diagnosis has received considerable interests over the past years. In this paper, a CT liver image diagnostic classification system is presented which will automatically find, extract the CT liver boundary and further classify liver diseases. The system comprises a detect-before-extract (DBE) system which automatically finds the liver boundary and a neural network liver classifier which uses specially designed feature descriptors to distinguish normal liver, two types of liver tumors, hepatoma and hemageoma. The DBE system applies the concept of the normalized fractional Brownian motion model to find an initial liver boundary and then uses a deformable contour model to precisely delineate the liver boundary. The neural network is included to classify liver tumors into hepatoma and hemageoma. It is implemented by a modified probabilistic neural network (PNN) [MPNN] in conjunction with feature descriptors which are generated by fractal feature information and the gray-level co-occurrence matrix. The proposed system was evaluated by 30 liver cases and shown to be efficient and very effective.

Algorithms↗
PubMed1998

Arginase modulates nitric oxide production in activated macrophages.

In macrophages and many other cell types, L-arginine is used as a substrate by both nitric oxide synthase (NOS) and arginase to produce nitric oxide (NO) and urea, respectively. Because the availability of L-arginine is a major determinant for NO synthesis in the activated macrophage, we hypothesized that NO production may be reduced by arginase via depleting the common substrate in this cell type. To test this hypothesis, we investigated the effect of an arginase inhibitor, L-norvaline, on NO production in J774A.1 mouse macrophages activated by lipopolysaccharide (LPS, 1.0 microgram/ml) for 22 h. In the absence of LPS, macrophages produced a low level of NO. In contrast, NO production from these cells was significantly increased in the presence of LPS. Increasing extracellular levels of L-arginine (0.01-0.8 mM) produced a concomitant increase in NO production of activated macrophages. L-Norvaline (10 mM), which specifically inhibits arginase activity (i.e., reducing urea production by 50%) without altering NOS activity, enhanced NO production (by 55%) from activated macrophages. The enhancement of NO production by L-norvaline was inversely related to the extracellular level of L-arginine. A more pronounced increase in NO production was observed at the lower level of extracellular L-arginine, i.e., a 55 vs. 28% increase for 0.05 and 0.1 mM extracellular L-arginine, respectively. When the L-arginine concentration exceeded 0.5 mM, the L-norvaline effect was abolished. These results indicate that arginase can compete with NOS for their common substrate and thus inhibit NO production. This regulatory mechanism may be particularly important when the extracellular supply of L-arginine is limited.

Animals↗
PubMed1997

An image capture and communication system for emergency computed tomography.

An image capture and communication system for emergency computed tomography (CT) is presented. The system, named ICCS, integrates CT scanners, personal computers (PC), network systems, an IBM API gateway and an IBM mainframe platform. The ICCS was implemented in the emergency unit in the Taichung Veterans General Hospital (TCVGH) and has received considerable support from the doctors, nurses and staff of the TCVGH emergency unit who have shown great interest in ICCS. This is because ICCS allows physicians in the emergency unit to examine patients' images on image viewing stations immediately after the patients are CT scanned. It also makes remote consultation possible for doctors who can stay where they are and consult with radiologists through the system and a hot line without leaving the emergency unit. This advantage greatly reduces the consultation time and saves many unnecessary trips between the emergency unit and the Department of Radiology.

Emergency Service, Hospital↗
PubMed1997

Cytotoxic constituents from the stems of Diospyros maritima.

One novel coumaric acid ester of lupeol, dioslupecin A (1), three naphthoquinones, 8'-hydroxyisodiospyrin (2), isodiospyrin (3), and plumbagin (4), three triterpenes, lupeol, lupenone and taraxerone, and four sterols, beta-sitosterol, stigmasterol, stigmast-4-en-3-one and ergosta-4,6,8(14),22-tetraen-3-one were isolated from the n-hexane extract of the stems of Diospyros maritima Blume. The structural determination of 1 was based on 1D and 2D NMR spectra (including 1H-1H COSY, 1H-13C COSY, and HMBC). All compounds were evaluated for in vitro cytotoxicity in 4 cancer cell lines. Compound 2 showed similar cytotoxicity against hepatoma (HEPA-3B, ED50 = 1.72 micrograms/ml), nasopharynx carcinoma (KB, ED50 = 1.85 micrograms/ml), colon carcinoma (COLO-205, ED50 = 2.24 micrograms/ml) and cervical carcinoma (HELA, ED50 = 1.92 micrograms/ml). Compounds 3 and 4 exhibited strong cytotoxicity against HEPA-3B, KB, COLO-205 and HELA (ED50 = 0.25, 1.81, 0.13 and 0.27 micrograms/ml for 3; ED50 = 0.87, 3.27, 0.56 and 0.35 micrograms/ml for 4, respectively.

Antineoplastic Agents, Phytogenic↗
PubMed1996

Malalignment-type ventricular septal defect in double-chambered right ventricle.

Double-chambered right ventricle (DCRV) is commonly associated with ventricular septal defect (VSD). In this study, an assessment was made of the relevance of a malalignment-type VSD to hemodynamic and morphologic features in DCRV. During an 8.5-year period, 53 patients with DCRV were enrolled after study with echocardiography, catheterization, and angiography. Patients were divided into 2 groups: group I included 40 patients, aged 3.7 +/- 3.2 years, with a malalignment-type VSD; group II consisted of 13 patients, aged 8.6 +/- 2.7 years, without a malalignment-type VSD. History of congestive heart failure in infancy was present in 21 group I and 2 group II patients (53% vs 15%, respectively, p <0.05). The mean pulmonary-to-systemic flow ratio was significantly higher in group I than in group II (1.89 +/- 0.74 vs 1.14 +/- 0.21, respectively, p <0.05). The mean pressure gradient across the right ventricular outflow tract was lower in group I than in group II (41 +/- 16 vs, 73 +/- 33 mm Hg, respectively, p <0.05). Among 42 patients who had a series of echocardiograms recorded, progression of pressure gradient was evident in 35: 28 in group I and 7 in group II. A subaortic ridge was present exclusively in 29 group I patients (73%). Prolapse of the aortic valve was present in 26 (49%): 20 group I (50%) and 6 group II (46%) patients. Aneurysm formation of the septal defect was found in 17 (43%) and 7 (54%) group I and II patients, respectively. It can be concluded that a history of congestive heart failure was more common in DCRV patients with a malalignment-type VSD. Malalignment-type VSD is significantly associated with a larger pulmonary-to-systemic flow ratio and subaortic ridge.

Adolescent↗
PubMed1996

Efficacy of ultrafiltration in removing inflammatory mediators during pediatric cardiac operations.

BACKGROUND: Conventional and modified ultrafiltration was used in pediatric cardiac operations to reduce volume overload and total body water. The purpose of this study was to compare the efficacy of these techniques in removing inflammatory mediators during cardiopulmonary bypass. METHODS: Fifty pediatric patients undergoing cardiac operations were randomized into a modified or conventional ultrafiltration group. Blood samples were obtained before and after ultrafiltration to assess the plasma concentrations of leukocyte elastase, tumor necrosis factor-alpha, interleukin-6, and interleukin-8. RESULTS: Except for plasma concentrations of tumor necrosis factor-alpha in the modified ultrafiltration group, the plasma concentrations of all the mediators measured increased after ultrafiltration in both groups of patients. The volume of ultrafiltrate and the total amounts of tumor necrosis factor-alpha and interleukin-6 removed by ultrafiltration were significantly greater in the modified group. The concentrations of mediators in the ultrafiltrate and the ratio of ultrafiltrate to plasma concentrations of the mediators did not differ between the groups. Ultrafiltration was more efficient in removing tumor necrosis factor-alpha than the other mediators. CONCLUSIONS: The efficacy in removing the inflammatory mediators generated during cardiopulmonary bypass did not differ between modified and conventional ultrafiltration.

Analysis of Variance↗
PubMed1996

[The development of shrimp blood agar for testing the hemolysis of shrimp's haemocyte by bacteria].

A new plating medium, shrimp blood agar, was developed by using the haemolymph of shrimp plus 200 ppm rose bengal as the substrate. The colorless shrimp haemocytes were dyed by rose bengal to red. On the present agar, the hemolytic bacteria strain may show a clear zone surrounding the bacterial colony. The result on hemolysis of 45 bacteria representing 12 genera isolated from aquaculture environments against shrimp blood agar and sheep blood agar was also evaluated. There are 11 strains with different results. The study showed that, with the aim of screening the hemolytic bacteria to shrimp, shrimp blood agar might reveal a relatively quick and accurate results than that of sheep blood agar.

Agar↗
PubMed1996

Continuous monitoring of venous oxygen saturation in critically-ill infants.

A 4-French gauge Opticath catheter, inserted into a neonate's right atrium through the right internal jugular vein, can be used to continuously monitor venous blood oxygen saturation in the right atrium. This method instantly detects subtle changes in cardiopulmonary function in small infants and neonates and enables the appropriate treatment to be given in cases of critical infantile and neonatal cardiopulmonary deterioration. This report discusses four neonatal and infantile patients who underwent continuous monitoring of venous blood oxygen saturation in the right atrium. Continuous monitoring allowed appropriate treatment to be given earlier compared to conventional monitoring methods of blood pressure and heart rate.

Cardiac Catheterization↗
PubMed1995

Implication of anterior septal malalignment in isolated ventricular septal defect.

OBJECTIVE: The aim was to define the long term prognosis of isolated ventricular septal defect (VSD) with anteriorly malaligned outlet septum. DESIGN: Cohort study. SETTING: University hospital, tertiary medical care centre. PATIENTS: Between July 1986 and June 1993, 63 patients were studied with an isolated VSD and anteriorly malaligned outlet septum (59 perimembranous; 4 muscular outlet). MAIN OUTCOME MEASURES: The diagnosis of septal malalignment, aneurysmal transformation, right ventricular obstruction, subaortic ridge, and aortic valve prolapse was based on echocardiographic criteria, then confirmed by angiography in 33 patients and by surgery in 28. An actuarial curve for each event was obtained by Kaplan-Meier non-parametric analysis and the significance was examined by log-rank test. RESULTS: Aneurysmal transformation decreased the size of the VSD in 52% of the patients, but was also associated with the appearance of subaortic ridge (p < 0.05). Progressive obstruction in the right ventricle was observed in 51%, more often in those without aneurysmal transformation (p < 0.05). Aortic valve prolapse was quite common whether or not aneurysmal transformation occurred (33% and 23%, respectively). This was attributed to the location of the VSD and the anterior malalignment of the outlet septum. Surgery was performed in 28 patients at a median age of 50 months because of significant left to right shunt (n = 5), or the development of obstruction in right ventricle (n = 9), aortic valve prolapse (n = 3), or combinations (n = 11). The presence of subaortic ridge per se was not considered to be a surgical indication. CONCLUSIONS: Anteriorly malaligned VSDs have variable presentation. Careful echocardiographic evaluation is needed to identify various combinations of progressive right ventricular obstruction, aneurysmal transformation, subaortic ridge, or aortic valve prolapse. In extreme cases a patient may have a pathology complex comprising right ventricular outflow obstruction, subaortic ridge, aortic valve prolapse, and anteriorly malaligned VSD.

Child, Preschool↗
PubMed1995

[The first successful case or Norwood operation for hypoplastic left heart syndrome in Taiwan].

UNLABELLED: Hypoplastic left heart syndrome is not infrequently seen in Taiwan, but all died previously. An 8 day-old-male baby suffering from hypoplastic left heart syndrome was transferred to our hospital after cardiopulmonary resuscitation. Oral prostaglandin E2 was used to maintain ductal patency and carbon dioxide was used through a respirator to control his pulmonary blood flow. He underwent Norwood operation at age 15 days under deep hypothermia and circulatory arrest. The postoperative course was smooth and occasional tachypnea was controlled by carbon dioxide inhalation through a mask. A follow up echocardiogram showed patent shunt and neoaortic pathway, good interatrial communication and mild tricuspid regurgitation. The baby survived and has fared well 2 years postoperatively. CONCLUSION: We recommend carbon dioxide manipulation before and after the Norwood operation for hypoplastic left heart syndrome with increased pulmonary blood flow uncontrollable by the respirator.

Carbon Dioxide↗
PubMed1994

Stenosis of pulmonary veins with ventricular septal defect: visualization of the pulmonary veins after pulmonary arterial banding.

A case of 'absent' left pulmonary vein with ventricular septal defect was diagnosed based on echocardiography, magnetic resonance imaging and cardiac catheterization at newborn stage. Pulmonary arterial banding was performed at the age of 1 month to ameliorate the pulmonary flow. At a cardiac catheterization 1 year later, the left pulmonary veins were visualized with moderate stenosis at their entrance into the left atrium. The patient has been stable after surgical repair of the ventricular septal defect and dilation of the pulmonary venous stenosis.

Cardiac Catheterization↗
PubMed1994

Characterization of aneurysmal transformation in perimembranous ventricular septal defects: an adhered anterior leaflet of tricuspid valve predisposes to the development of left ventricular-to-right atrial shunt.

BACKGROUND: The most common type of left ventricular-to-right atrial shunts are those associated with perimembranous ventricular septal defect when the defects diminish in size via aneurysmal transformation. This study is to characterize the echocardiographic features and to determine the possible mechanisms. METHODS AND RESULTS: From January 1986 to December 1992, of 930 consecutive patients with isolated perimembranous ventricular septal defect, 692 showed evidence of aneurysmal transformation. Excluding those with subaortic ridge, echocardiographic analysis was based on 664 of them. Of these, 94 patients had left ventricular-to-right atrial shunts, 115 had their defects spontaneously closed and in 455 only interventricular shunt persisted. Four types of echocardiographic findings featured in the aneurysmal transformation process: type A, both the anterior and septal leaflets of tricuspid valve contributed to the process; type B was similar to type A, but the arc-like structure from the anterior leaflet is much less evident; in type C, only the septal leaflet, and in type D, other adjacent tissues, contribute to the aneurysmal transformation. Type A morphology was closely associated with the development of left ventricular-to-right atrial shunt while types C and D were most commonly seen in those spontaneously closed defects and those with only interventricular shunt. The vegetations of infective endocarditis were located at the atrial side of the tricuspid valve in patients with left ventricular-to-right atrial shunts, while they were in the right ventricle in those with only interventricular shunt. CONCLUSION: The morphology of the aneurysmal transformation in perimembranous ventricular septal defect can be characterized by echocardiograms. Although the septal leaflet of the tricuspid valve is usually involved in this process, it is the incorporation of the anterior leaflet that predisposes to the development of left ventricular-to-right atrial shunts.

Cardiac Catheterization↗
PubMed1993

Implication of aneurysmal transformation in isolated perimembranous ventricular septal defect.

Defects on the membranous ventricular septum (perimembranous ventricular septal defect [VSD]) may spontaneously close or diminish in size by "aneurysmal transformation" (i.e., adherence of the tricuspid valve or adjacent tissue onto the VSD). It was recently shown that the appearance of aneurysmal transformation may be associated with subaortic ridges, as well as left ventricular (LV)-to-right atrial (RA) shunts. In all, 877 consecutive patients with isolated perimembranous VSD were retrospectively studied. Results of actuarial analysis showed that patients with a perimembranous VSD had a 98% probability of aneurysmal transformation by the age of 240 months. Of these patients, the expected probabilities of developing LV-RA shunt, spontaneous closure and subaortic ridge were 45, 35 and 6%, respectively. Patients with LV-RA shunts had higher probabilities of developing infective endocarditis (p = 0.002) and persistent left-to-right shunts (p < 0.001). The presence of a subaortic ridge may be accompanied by LV outflow tract obstruction (10 of 25 patients), infundibular pulmonary stenosis (n = 3), or aortic valve deformity or aortic regurgitation (n = 5), and none of those with a subaortic ridge closed spontaneously. It was confirmed that a substantial proportion of aneurysmal transformation of isolated perimembranous VSD is associated with LV-RA shunts and subaortic ridges.

Age Factors↗
PubMed1993

Pericardial color Doppler flow in postpericardiotomy effusive constrictive pericarditis.

A laminar color Doppler flow was discovered in the pericardial space in a 35-year-old man with postpericardiotomy effusive constrictive pericarditis. The flow was detected by transesophageal color Doppler echocardiography. A further pulsed Doppler study revealed a to-and-fro flow, which was synchronized with the cardiac rhythm. We hypothesized that this flow was generated by the rhythmic cardiac contraction. It was then augmented by hard fibrous pericardium and became detectable by color Doppler echocardiography. Pericardial effusion is a frequent echocardiographic finding but little attention has been paid to the flow in it. The laminar flow in the pericardial space in our patient is related to his hard pericardium and can aid in making the diagnosis of effusive constrictive pericarditis. We suggest that flow in the pericardial space deserves more attention and may provide valuable diagnostic aid.

Adult↗
PubMed1992

Nuclear localization signals, but not putative leucine zipper motifs, are essential for nuclear transport of hepatitis delta antigen.

Hepatitis delta antigen (HDAg) is the only known protein of hepatitis delta virus and was previously shown to localize in the nucleoplasm of infected liver cells. In this study, nuclear localization signals of HDAg were defined by expressing various domains of the antigen in both hepatic and nonhepatic cells as beta-galactosidase fusion proteins. A cytochemical staining assay demonstrated that a domain from amino acid residues 35 to 88 of HDAg was able to facilitate transport to the nucleus of the originally cytoplasm-localized protein beta-galactosidase. Two nuclear localization signals, NLS1 and NLS2, which are similar to those of simian virus 40 T antigen and polyomavirus T antigen, respectively, were identified. Either NLS1 or NLS2 alone was sufficient for the nuclear transport of HDAg. However, a fusion protein (N65Z) containing beta-galactosidase and the N-terminal 65 amino acids of HDAg, containing NLS1, was localized exclusively in the cytoplasm and perinuclear region. A possible hydrophobic subdomain between amino acid residues 50 and 65 may block the function of NLS1. Nevertheless, N65Z could enter the nuclei of transfected cells when it was coexpressed with full-length HDAg. Entry into the nucleus may be mediated by the coiled-coil structure rather than the putative leucine zipper motif located between amino acid residues 35 and 65. The existence of two independent nuclear localization signals may ensure the proper functioning of HDAg in the multiplication of delta virus in the nucleus. In addition, two putative casein kinase II sites (SRSE-5 and SREE-126) that may be important in controlling the rate of nuclear transport were found in HDAg.

Amino Acid Sequence↗