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Peptidoglycan (PG) is a highly cross-linked, protective mesh-like sacculus that surrounds the bacterial cytoplasmic membrane. Expansion of PG is tightly coupled to growth of a bacterial cell and requires hydrolases to cleave the cross-links for insertion of nascent PG material. In Escherichia coli, a proteolytic system comprising the periplasmic PDZ-protease Prc and the lipoprotein adaptor NlpI contributes to PG enlargement by regulating cellular levels of MepS, a cross-link-specific hydrolase. Here, we demonstrate how NlpI binds Prc to facilitate the degradation of its substrate MepS by structural and mutational analyses. An NlpI homodimer binds two molecules of Prc and forms three-sided MepS-docking cradles using its tetratricopeptide repeats. Prc forms a monomeric bowl-shaped structure with a lid-like PDZ domain connected by a substrate-sensing hinge that recognizes the bound C terminus of the substrate. In summary, our study reveals mechanistic details of protein degradation by the PDZ-protease Prc bound to its cognate adaptor protein. [ABSTRACT FROM AUTHOR]

Ebstein's anomaly is a rare, congenital cardiac anomaly that may result in cyanosis, right heart failure, and tachyarrhythmia during the newborn stage or after adolescence. This study investigated the data of 77 patients diagnosed between 1980 and 2006 at a tertiary care center in Taiwan. Patients were grouped into either an early group or a late group. Survival declined rapidly within the newborn stage in the early group, but declined only during the third decade in the late group. Surgical results were poor (20% success rate) for neonatal systemic-to-pulmonary shunts in those cases with associated pulmonary atresia, but were satisfactory for other surgical modes. Supraventricular tachyarrhythmia occurred in 31 (41%) patients at a median age of 10 years and could be eliminated by radiofrequency ablation (81% success rate), though the recurrence rate was high (41%). In conclusion, other than those cases requiring shunts at the newborn stage, the long-term outcome was favorable. [ABSTRACT FROM AUTHOR]

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital cardiac defect that usually presents as dilated cardiomyopathy in infancy. From 1984 to 2005, 13 (five males and eight females, 0.13%) out of 9,950 patients with congenital heart disease were identified as ALCAPA at our institute. Corrective surgery was performed at a median age of 9 months (range: 2 months to 5 years). Eleven patients underwent direct reimplantation of the left coronary artery (LCA) to the aorta, while two received extrapulmonary baffling. The overall survival rate was 92%. Only one patient died 5 months after reimplantation of the LCA due to acute myocardial ischaemia. Left ventricular ejection fraction (LVEF) was significantly lower in the eight (62%) patients operated during infancy than in those operated beyond 5 months (median: 35% vs. 75%). Left ventricle function was normalised in 11 patients (85%). Among the eight patients without concomitant mitral annuloplasty, mitral regurgitation (MR) improved to a mild or trivial degree in six patients and remained at the pre-operative level in two patients. Pathologic Q wave was noted in 11 patients, which eventually regressed in all except two cases. The median interval of recovery was 16 days, 6 months and 24 months for MR, LVEF and electrocardiogram (ECG) changes, respectively. In conclusion, ALCAPA is also a rare disease in Asian countries, such as Taiwan. The subsequent recovery of MR, left ventricular (LV) function and even pathologic Q wave can be expected after dual coronary repair, regardless of the age at repair. [ABSTRACT FROM AUTHOR]

This study is based on a database of 16 years; we sought to define the incidence and outcome of scimitar syndrome. Of 8,771 patients, 5 (0.057%) with scimitar syndrome were identified and constituted the study population. Follow-up ranged from 1 to 16 years (median: 10 years). Diagnosis was assured by computed tomography in four patients and by cardiac catheterization in one. Two patients presented with respiratory distress soon after birth and required early pneumonectomy in one case and coil embolization of the abnormal feeding arteries to the right lower lung followed by surgical rerouting of the abnormal pulmonary vein and repair of the atrial septal defect in the other case. The former was supported by ventilator therapy for 3 years after pneumonectomy, but was finally weaned from the ventilator. Among the other three, two had repeated pneumonia that resolved after rerouting of the abnormal right pulmonary vein and cardiac repair. The asymptomatic child did not receive any intervention. In spite of the abnormal orientation of the airways, none of the four patients with detailed computed tomography imaging showed any significant compression of the airways. All five patients were doing well as of the last follow-up. In conclusion, scimitar syndrome is a very rare disease in this Asian country and the varied symptoms, such as tachypnea and repeated infection, could be improved after interventions. [ABSTRACT FROM AUTHOR]