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Chung-I Chang

Publications and source records attributed to Chung-I Chang.

At least 19 recordsLinked to original sources
PubMed2006

Coronary artery anatomy in children with congenital heart disease by computed tomography.

AIMS: To evaluate electron beam computed tomography (EBCT) for recognition of coronary artery patterns in children with congenital heart diseases. METHODS: Institutional review board approval was obtained; informed consents were not required. A total of 226 children diagnosed with Tetralogy of Fallot (n=122), double outlet right ventricle (n=52), transposition of the great arteries (n=34), and congenitally corrected transposition (n=18) who had undergone cardiac EBCT at our institution between 1995 and 2002 were identified. Iodinated contrast medium was injected with arterial phase acquisition. The two radiologists and one pediatric cardiologist that interpreted the EBCT images and cardiac angiograms, respectively, were blinded to each other's results. Surgical and cardiac angiogram findings were compared to the EBCT results. Descriptive statistics were used to compare efficacy. RESULTS: Numerous aberrant patterns were clearly identified on the EBCT images. Pattern IX occurred in most patients with Tetralogy of Fallot or double outlet right ventricle. Patterns I and 0 are the most common coronary artery types in transposition of the great arteries and congenitally corrected transposition, respectively. Overall diagnostic accuracy for all disease groups was 82.7%. The diagnostic accuracy of the coronary arterial anatomy by EBCT increased with older age, and was more than 90% in individuals aged over 3 months. CONCLUSION: EBCT is effective for identification of the coronary anatomy of children with specific congenital heart diseases, except for neonates and small infants less than 3 months of age.

Adolescent↗
PubMed2006

Structure of tracheal cytotoxin in complex with a heterodimeric pattern-recognition receptor.

Tracheal cytotoxin (TCT), a naturally occurring fragment of Gram-negative peptidoglycan, is a potent elicitor of innate immune responses in Drosophila. It induces the heterodimerization of its recognition receptors, the peptidoglycan recognition proteins (PGRPs) LCa and LCx, which activates the immune deficiency pathway. The crystal structure at 2.1 angstrom resolution of TCT in complex with the ectodomains of PGRP-LCa and PGRP-LCx shows that TCT is bound to and presented by the LCx ectodomain for recognition by the LCa ectodomain; the latter lacks a canonical peptidoglycan-docking groove conserved in other PGRPs. The interface, revealed in atomic detail, between TCT and the receptor complex highlights the importance of the anhydro-containing disaccharide in bridging the two ectodomains together and the critical role of diaminopimelic acid as the specificity determinant for PGRP interaction.

Amino Acid Sequence↗
PubMed2006

Clinical implication of blood levels of B-type natriuretic peptide in pediatric patients on mechanical circulatory support.

BACKGROUND: B-type natriuretic peptide (BNP) is a marker of heart failure. In adult patients with heart failure, decreased BNP levels after implantation of ventricular assist devices may be indicative of recovery. However, BNP levels among pediatric patients receiving mechanical support are largely unknown. METHODS: Fifteen pediatric patients with cardiogenic shock who were supported by extracorporeal membrane oxygenation (ECMO) were evaluated. The BNP levels were determined before ECMO initiation, during ECMO support, and after ECMO removal. RESULTS: All patients had elevated BNP levels before initiation of ECMO (median, 1,430 pg/mL; range, 361 to 5,000 pg/mL). Among the 15 patients, 1 received heart transplantation. Extracorporeal membrane oxygenation was withdrawn in 2 patients, and the other 12 patients were weaned from ECMO. Four patients died after initially successful weaning from ECMO. The BNP levels of the nonsurvivors (median, 3,685 pg/mL; range, 2,494 to 5,000 pg/mL) were higher than those of the survivors (median, 1,127pg/mL; range, 108 to 3,030 pg/mL) on the next few days after ECMO removal (p = 0.016). The BNP levels on the fourth day after removal of ECMO among the survivors (median, 498 pg/mL; range, 108 to 890 pg/mL) were lower than those among the nonsurvivors (median, 3,900 pg/mL; range, 3,230 to 5,000 pg/mL; p = 0.017). CONCLUSIONS: Among pediatric patients supported with ECMO, the survivors had lower BNP levels than those who did not survive. We suggest that serial blood BNP levels can be potential markers for monitoring pediatric patients on mechanical circulatory support, and the concept merits further study.

Biomarkers↗
PubMed2006

Noninvasive diagnosis of aortic coarctation in neonates with patent ductus arteriosus.

OBJECTIVES: To find a noninvasive method to detect coarctation of the aorta (CoA) in the presence of a patent ductus arteriosus (PDA) in neonates. STUDY DESIGN: From 1994 to 1998, 36 neonates with CoA and PDA confirmed by surgery or cardiac catheterization were studied; another 19 neonates with isolated PDA served as control patients. The prospective study was conducted from 2001 to 2002 on 162 neonates. RESULTS: Among the 36 neonates in the CoA group, 14 patients (39%) had blood pressure discrepancy, 26 patients (72%) had a visualized posterior shelf by echocardiogram, and the ratio of isthmus/descending aorta diameters (I/D ratio) was below 0.64 in 32 patients (89%). None of the control patients had these features. A diagnostic approach was subsequently proposed, according to which a neonate with PDA who fulfilled any of the above features was diagnosed as CoA plus PDA. In the prospective study, the sensitivity and positive predictive values of this method were both 91.7%, whereas the specificity and negative predictive values were both 99.3%. CONCLUSIONS: Echocardiographic measurements of I/D ratio along with the delineation of posterior shelf and a BP discrepancy can satisfactorily identify CoA in the presence of PDA in neonates.

Aorta↗
PubMed2006

Surgical outcome of aortopulmonary window repair in early infancy.

BACKGROUND/PURPOSE: Aortopulmonary window (APW) is a rare congenital heart disease and surgical correction is advised as early as possible. However, few studies have focused on infants. This study sought to define the clinical features and outcomes in patients who underwent surgical repair of APW in early infancy. METHODS: Between 1983 and 2004, there were 14 patients (0.15%) with APW out of 9414 patients with congenital heart disease. Ten underwent surgical repair of APW when they were younger than 4 months of age and constituted the study population. RESULTS: There were four patients with type I APW, three with type II and three with type III. Concomitant cardiovascular anomalies were present in all patients, mainly aortic arch anomalies (80%, including right aortic arch, interrupted aortic arch [IAA] and severe coarctation of the aorta [CoA]). Patients were further grouped according to the presence (n = 5) or absence (n = 5) of IAA or severe CoA. All patients underwent surgical repair of APW with various techniques, including direct ligation, division and patch or flap closure. There was one early postoperative death. None of the survivors died during a median follow-up of 34 months (range, 8-116 months). Patients with IAA or severe CoA had longer intubation time, intensive care unit stay and hospital stay. Early reintervention was required only in patients with IAA or severe CoA (n = 3, 60%). Among them, two had significant residuals and both had type III APW. CONCLUSION: Long-term outcomes are generally good in patients with APW who have undergone surgical correction in early infancy. However, associated IAA or severe CoA may predict a prolonged hospital course and an increased risk of early reintervention. In patients with type III APW requiring early reintervention, significant hemodynamic residuals may be common even after reintervention.

Aortopulmonary Septal Defect↗
PubMed2006

Effects of sildenafil on pulmonary hypertension and levels of ET-1, eNOS, and cGMP in aorta-banded rats.

Sildenafil, an oral phosphodiesterase Type 5 inhibitor, has vasodilatory effects through a cGMP-dependent mechanism. We previously showed that aortic banding could result in left ventricular overloading and pulmonary hypertension (PH). In this study, we investigated whether early administration of sildenafil, either immediately after or 2 weeks after aortic banding, could ameliorate the development of PH and alter gene expression of endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS), and alter the levels of cGMP in rats undergoing an ascending aortic banding. Rats (n = 32) were divided into sham-operated and banding groups with or without treatment. The banded rats were further divided into three groups: (i) receiving saline on Days 1-28 (AOB28; n = 8), (ii) receiving saline on Days 1-14 followed by treatment with 50 mg/kg/day sildenafil on Days 15-28 (AOB28/Sil(15-28); n = 8), and (iii) receiving 50 mg/kg/day sildenafil on days 1-28 (AOB28/Sil(1-28); n = 8). The sham-operated rats were administrated saline on Days 1-28 (n = 8). Four weeks after banding, there was a significant development of PH with pulmonary vascular remodeling. Although both sildenafil-treatment groups had significant increases in cGMP and had reductions in the thickening in the medial layer of pulmonary arteriole, notable attenuation of PH occurred only in the AOB28/Sil(1-28) group. PreproET-1 and eNOS messenger RNA (mRNA) expressions were measured by competitive reverse transcription polymerase chain reaction, and eNOS protein was determined by Western blotting. Sildenafil did not alter the elevated ET-1 or preproET-1 mRNA in banded rats. Interestingly, pulmonary eNOS increased in the AOB28/Sil(1-28) group. In conclusion, early treatment with sildenafil inhibited the rise in pulmonary arterial pressure and pulmonary vascular remodeling in PH secondary to heart failure, and cGMP, but not ET-1, might be involved. Clinically, early repeated administration of sildenafil may offer an alternative in protecting against PH in heart failure.

Animals↗
PubMed2006

The effects of debanding on the lung expression of ET-1, eNOS, and cGMP in rats with left ventricular pressure overload.

Pulmonary hypertension (PH) usually develops secondary to left ventricular (LV) dysfunction; therefore, it is also called retrograde PH. To investigate our hypothesis that PH is at least partially reversible, as in some congenital heart diseases, in a rat model we investigated whether release of constriction could attenuate pulmonary vascular remodeling and change the expression of endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS). We used rats with LV dysfunction produced by an ascending aortic banding. In this study, there were four groups enrolled: 4-weeks banded (AOB(1-28); n = 7), 7-weeks banded (AOB(1-49); n = 7), debanded groups (AOB(1-28)/DeB(29-49); n = 7), and rats receiving a sham operation (n = 7). Subsequently, there was significant attenuation of medial hypertrophy in pulmonary arterioles and reversal of PH in the AOB(1-28)/DeB(29-49) group (sham, 19 +/- 1.3 mm Hg; AOB(1-28), 31 +/- 2.7 mm Hg; AOB(1-49), 32 +/- 2.7 mm Hg; and AOB(1-28)/DeB(29-49), 20 +/- 1.3 mm Hg). PreproET-1 mRNA and eNOS mRNA were measured by competitive reverse transcriptase (RT) polymerase chain reaction (PCR), and eNOS was measured by Western blotting. Compared with the banded groups, debanding significantly decreased pulmonary preproET-1 mRNA, pulmonary ET-1 (sham, 210 +/- 12 pg/g protein; AOB(1-28), 242 +/- 12 pg/g protein; AOB(1-49), 370 +/- 49 pg/g protein; and AOB(1-28)/DeB(29-49), 206 +/- 1.9 pg/g protein), and plasma ET-1 levels (sham, 10.1 +/- 1.5 pg/ml; AOB(1-28), 13.4 +/- 2.0 pg/ml; AOB(1-49), 15.4 +/- 2.0 pg/ml; and AOB(1-28)/DeB(29-49), 10.3 +/- 0.9 pg/ml protein). Debanding could not, however, alter pulmonary eNOS, eNOS mRNA, or cGMP. These findings suggest that pulmonary vascular remodeling, increased pulmonary arterial pressure, and upregulation of ET-1 gene expression are all reversible. We infer that it is the upregulated gene expression of ET-1, not eNOS, that is closely related to the development of the PH secondary to 4 weeks of aortic banding.

Animals↗
PubMed2005

Structure of the ectodomain of Drosophila peptidoglycan-recognition protein LCa suggests a molecular mechanism for pattern recognition.

The peptidoglycan-recognition protein LCa (PGRP-LCa) is a transmembrane receptor required for activation of the Drosophila immune deficiency pathway by monomeric Gram-negative peptidoglycan. We have determined the crystal structure of the ectodomain of PGRP-LCa at 2.5-A resolution and found two unique helical insertions in the LCa ectodomain that disrupt an otherwise L-shaped peptidoglycan-docking groove present in all other known PGRP structures. The deficient binding of PGRP-LCa to monomeric peptidoglycan was confirmed by biochemical pull-down assays. Recognition of monomeric peptidoglycan involves both PGRP-LCa and -LCx. We showed that association of the LCa and LCx ectodomains in vitro depends on monomeric peptidoglycan. The presence of a defective peptidoglycan-docking groove, while preserving a unique role in mediating monomeric peptidoglycan induction of immune response, suggests that PGRP-LCa recognizes the exposed structural features of a monomeric muropeptide when the latter is bound to and presented by the ectodomain of PGRP-LCx. Such features include N-acetyl glucosamine and the anhydro bond in the glycan of the muropeptide, which have been demonstrated to be critical for immune stimulatory activity.

Animals↗
PubMed2005

Aortic valve prolapse associated with outlet-type ventricular septal defect.

BACKGROUND: Aortic valve prolapse is frequently associated with juxta-arterial ventricular septal defect. The significance of its association with other outlet types of ventricular septal defect, however, remains unclear. METHODS: From 1987 to 2002, 677 patients (male:female ratio, 424:253) who received surgical repair for ventricular septal defect extending to the outlet septum were reviewed. Based on surgical findings, ventricular septal defects were classified as juxta-arterial, perimembranous outlet, or muscular outlet type. RESULTS: Aortic valve prolapse occurred in 373 of 677 patients (57.2%) with 209 juxta-arterial, 103 perimembranous outlet, and 61 muscular outlet type. Significant aortic regurgitation developed in 51 of 373 (14%). Among 252 patients with regular follow-up, the mean onset ages of aortic valve prolapse in juxta-arterial, perimembranous outlet, and muscular outlet type were 4.9, 5.0, and 5.1 years, respectively (no statistical difference). The presence of larger shunt and probably anterior malalignment predicted an earlier onset of aortic valve prolapse. Perimembranous outlet and muscular outlet type ventricular septal defect were frequently associated with infundibular hypertrophy and subaortic ridge, and perimembranous outlet type was associated with anterior septal malalignment. In juxta-arterial ventricular septal defect and ventricular septal defect with anterior malalignment, prolapsed cusp was always the right coronary cusp, but noncoronary cusp involvement was also common in perimembranous outlet type (17 of 103, 16.5%). CONCLUSIONS: The association with anterior septal malalignment, infundibular stenosis and subaortic ridge is related to the location of the outlet ventricular septal defect. The age of onset of aortic valve prolapse in each type was quite similar, and a larger shunt may predict an earlier onset.

Adolescent↗
PubMed2005

The safe use of intraoperative transesophageal echocardiography in the management of total anomalous pulmonary venous connection in newborns and infants: a case series.

BACKGROUND: Intraoperative transesophageal echocardiography (TEE) is useful in evaluating the repair of lesions in patients with congenital heart disease. But the use of TEE in infants with total anomalous pulmonary venous connection (TAPVC) remains unclear. We reviewed the safety and efficacy of intraoperative TEE during TAPVC repair. METHODS: Twenty-eight consecutive 1 day to 7 month-old infants with TAPVC (14 supracardiac, six intracardiac and eight infracardiac type) had surgical repair with intraoperative TEE monitoring. RESULTS: Four patients received immediate surgical revision after primary surgery for residual anastomotic stenosis diagnosed by TEE. In addition, two unsuspected ventricular septal defects and three persistent ductus arteriosus were detected before surgery. Eight infants (29%) had hypotension and hypoxemia associated with TEE probe insertion before surgery, but this hemodynamic disturbance returned to baseline value after withdrawing the TEE probe from the esophagus. However, these eight patients had uneventful TEE probe insertion following sternotomy. The mechanism was probably because of the reduction of intrathoracic pressure when the chest was opened. CONCLUSIONS: TEE probe insertion in TAPVC patients may pose a potential risk of compression of pulmonary venous confluence resulting in hemodynamic instability. Therefore, we suggest that the use of TEE in such TAPVC patients appears to be safer after sternotomy.

Echocardiography, Transesophageal↗
PubMed2005

Clinical manifestations and outcomes of constrictive pericarditis in children.

BACKGROUND AND PURPOSE: Constrictive pericarditis (CP) is rare in children. The purpose of this study was to define the clinical manifestations and outcomes of this disease. METHODS: From January 1985 through December 2003, 8 patients with surgically confirmed CP were enrolled. Data on clinical characteristics, disease manifestations, treatment, and outcomes were collected and analyzed. RESULTS: One patient had l-transposition of the great arteries (l-TGA); the other 7 patients had no underlying cardiovascular diseases. None of the patients had direct evidence of tuberculous infection. Age at disease onset ranged from 8 months to 13 years (median, 10 years), and the interval between symptom onset and correct diagnosis ranged from 2 to 31 months (median, 12 months). Major symptoms and signs included abdominal distension, hepatomegaly, neck vein engorgement and ascites. Evidence of calcification on chest roentgenogram was found in 1 patient (12.5%). Computed tomography or magnetic resonance image studies showed pericardial thickening in 6 patients (75%). Seven patients underwent cardiac catheterization, and all hemodynamic data met the diagnostic criteria for CP. All patients with structurally normal hearts survived during a median follow-up of 31 months after pericardiectomy (range, 5 to 103 months). The patient with l-TGA died of pneumonia 1 year after pericardiectomy. CONCLUSIONS: Symptoms and signs of right heart failure were common in children with CP. The etiology of CP remains largely unknown. Patients with structurally normal hearts have good outcomes after pericardiectomy.

Adolescent↗
PubMed2005

Ross procedure for pediatric aortic valve disease.

BACKGROUND AND PURPOSE: Currently, prosthetic selection for aortic valve replacement is still debatable in pediatric patients with aortic valve disease. Ross procedure is a time-consuming and demanding technique which may produce good results. This study assessed the results obtained with various methods of right ventricle outflow tract (RVOT) reconstruction in patients receiving Ross procedure. METHODS: From September 1996 to December 2003, 13 pediatric patients underwent Ross procedure for aortic valve disease. Their ages ranged from 1 month to 17 years (mean, 6.29 +/- 3.62 years; median, 7 years) and 2 patients were less than 1 year of age. Previous procedures in these patients included balloon dilation of the aortic valve in 10 and surgical aortic valvuloplasty in 2. RVOT was reconstructed with heterografts in 3, homografts in 3 or without extracardiac conduits in 7. RESULTS: There was 1 in-hospital death (7.7%) and 1 late death from a non-cardiac cause. One patient developed infective endocarditis with periaortic abscess 2 weeks after the Ross procedure. Eleven patients were followed for a mean of 3.3 years (range, 8 months to 8 years). There was no significant pressure gradient across the neoaorta. Severe stenosis developed gradually in 3 patients who had RVOT reconstruction with heterograft conduits. All 3 had received RVOT redo operation. None of the patients who received RVOT reconstruction without extracardiac conduits had significant pulmonary stenosis but 6 had regurgitation (nil 1, mild 3, moderate 3). No redo operation was required during follow-up (range, 8 months to 4 years). All of the 11 survivors were in New York Heart Association functional class I. CONCLUSIONS: This study found satisfactory results of Ross procedure in pediatric aortic valve disease. RVOT reconstruction without extracardiac conduit is a feasible alternative despite the availability of homograft.

Adolescent↗
PubMed2004

A Drosophila pattern recognition receptor contains a peptidoglycan docking groove and unusual L,D-carboxypeptidase activity.

The Drosophila peptidoglycan recognition protein SA (PGRP-SA) is critically involved in sensing bacterial infection and activating the Toll signaling pathway, which induces the expression of specific antimicrobial peptide genes. We have determined the crystal structure of PGRP-SA to 2.2-A resolution and analyzed its peptidoglycan (PG) recognition and signaling activities. We found an extended surface groove in the structure of PGRP-SA, lined with residues that are highly diverse among different PGRPs. Mutational analysis identified it as a PG docking groove required for Toll signaling and showed that residue Ser158 is essential for both PG binding and Toll activation. Contrary to the general belief that PGRP-SA has lost enzyme function and serves primarily for PG sensing, we found that it possesses an intrinsic L,D-carboxypeptidase activity for diaminopimelic acid-type tetrapeptide PG fragments but not lysine-type PG fragments, and that Ser158 and His42 may participate in the hydrolytic activity. As L,D-configured peptide bonds exist only in prokaryotes, this work reveals a rare enzymatic activity in a eukaryotic protein known for sensing bacteria and provides a possible explanation of how PGRP-SA mediates Toll activation specifically in response to lysine-type PG.

Amino Acid Sequence↗
PubMed2003

Usefulness of three-dimensional electron beam computed tomography for evaluating tracheobronchial anomalies in children with congenital heart disease.

This study was undertaken to delineate tracheobronchial anomalies associated with congenital heart disease. From June 1995 to December 2000, 1,245 children with congenital heart disease underwent cardiac electron beam computed tomography with 3-dimensional reconstruction on an independent workstation. Tracheobronchial anomalies are strongly associated with congenital heart disease and accompanying tracheal stenosis is not uncommon. With 3-dimensional reconstruction, electron beam computed tomography provided excellent anatomic definition of the central tracheobronchial abnormalities.

Abnormalities, Multiple↗
PubMed2003

Electron beam computed tomography appearance of endocardial fibroelastosis EBCT appearance of endocardial fibroelastosis.

Recent reports of endocardial fibroelastosis (EFE) have not reported the disease to be correctly diagnosed during the patients' life spans. Our purpose in this communication is to provide some feasible approaches toward correct diagnosis at the primitive stage and possible correlations to the prognosis. We analyzed five cases of EFE from 1997 to 2001. Four had pathology proven EFE. Data were sampled from the clinical symptoms, eletrocardiography, echocardiography, electron beam computed tomography (EBCT), management, and prognosis. A case of anomalous left coronary artery originating from main pulmonary artery diagnosed EFE correctly before death by utilizing an EBCT. The second case was double outlet of the right ventricle with severe calcification and fibrosis shown on EBCT studies, while the third case had severe calcification over both apices. Both patients required heart transplantation. The fourth case, with a decreasing ejection fraction, was idiopathic hypertropic subaortic stenosis with mild calcification and fibrosis on the EBCT images. The last stationary case had severe aortic stenosis with trivial fibrotic change and calcification. We propose that EBCT may accurately help to diagnose EFE before pathology confirmation. The magnitude of calcification and fibrotic thickness in the myocardium of the EBCT imaging may predict the outcome of EFE.

Adult↗