Impact of the pulmonary venous entry site morphology on postoperative pulmonary vein stenosis in total anomalous pulmonary venous connection patients.

Background: To evaluate the association between the pulmonary vein (PV) entry site morphology after total anomalous pulmonary vein repair (TAPVC) and postoperative pulmonary vein stenosis (PVS).

Methods: Computed tomography (CT) examination was performed to determine the PV entry site morphology. The width of the PV confluence was divided by the width of the left atrium (LA) to obtain the cPV/LA index.

Results and Complications After Single-Stage Repair of Aortopulmonary Window and Interrupted Aortic Arch in a 32-Week Preterm and a Full-Term Neonate.

BACKGROUND An aortopulmonary window (APW) is an uncommon congenital defect of the septation between the ascending aorta and pulmonary trunk. The combination of APW and interrupted aortic arch (IAA) is even rarer, with the hallmark characteristics of high peri-operative mortality and postoperative obstruction of the aortic arch, pulmonary artery, and left main bronchus. These complications often need re-interventions.

A 5+1 assemble-to-activate mechanism of the Lon proteolytic machine.

Many AAA+ (ATPases associated with diverse cellular activities) proteins function as protein or DNA remodelers by threading the substrate through the central pore of their hexameric assemblies. In this ATP-dependent translocating state, the substrate is gripped by the pore loops of the ATPase domains arranged in a universal right-handed spiral staircase organization. However, the process by which a AAA+ protein is activated to adopt this substrate-pore-loop arrangement remains unknown.

Structural basis for the hydrolytic activity of the transpeptidase-like protein DpaA to detach Braun's lipoprotein from peptidoglycan.

Cross-linking reaction of Braun's lipoprotein (Lpp) to peptidoglycan (PG) is catalyzed by some members of the YkuD family of transpeptidases. However, the exact opposite reaction of cleaving the Lpp-PG cross-link is performed by DpaA, which is also a YkuD-like protein. In this work, we determined the crystal structure of DpaA to provide the molecular rationale for the ability of the transpeptidase-like protein to cleave, rather than form, the Lpp-PG linkage.

Clinical outcomes of handmade polytetrafluoroethylene trileaflet-valved conduit used for pulmonary valve replacement.

Objectives: To mitigate the shortage of homograft sources, the use of handmade trileaflet expanded polytetrafluoroethylene valves in pulmonary valve replacement has shown excellent results from multicentre studies conducted in Japan. However, world-wide data outside Japan are relatively insufficient. This study presents the long-term results of a single surgeon's use of flipped-back trileaflet method in a 10-year case series.

Associated factors with parental pregnancy decision-making and use of consultation after a prenatal congenital heart disease diagnosis.

Background: Prenatal diagnosis of congenital heart disease (CHD) often leads affected families to experience psychological stress. Pediatric cardiology consultation is important in providing parents with sufficient information and reducing their anxiety to make an informed pregnancy decision. Involving a fetal nurse coordinator may optimize fetal anomaly care.

Resuscitated Sudden Cardiac Arrest of a Neonate with Congenital LQT Syndrome-Associated Torsades de Pointes: A Case Report and Literature Review.

Sudden infant death syndrome (SIDS), the most common cause of infant death in developed countries, is attributed to diverse trigger factors. Malignant cardiac dysrhythmias are potentially treatable etiologies, and congenital long QT syndrome (LQTS) is the most common cardiac ionic channelopathy confronted. β-Blockers or class Ib agents are the drugs of choice for the control of arrhythmias, and an implantable cardioverter defibrillator (ICD) should be considered for secondary prevention in survivors of lethal cardiac death.

Structural Basis for the Peptidoglycan-Editing Activity of YfiH.

Bacterial cells are encased in peptidoglycan (PG), a polymer of disaccharide -acetylglucosamine (GlcNAc) and -acetyl-muramic acid (MurNAc) cross-linked by peptide stems. PG is synthesized in the cytoplasm as UDP-MurNAc-peptide precursors, of which the amino acid composition of the peptide is unique, with l-Ala added at the first position in most bacteria but with l-Ser or Gly in some bacteria. YfiH is a PG-editing factor whose absence causes misincorporation of l-Ser instead of l-Ala into peptide stems, but its mechanistic function is unknown.

Processive cleavage of substrate at individual proteolytic active sites of the Lon protease complex.

The Lon protease is the prototype of a family of proteolytic machines with adenosine triphosphatase modules built into a substrate degradation chamber. Lon is known to degrade protein substrates in a processive fashion, cutting a protein chain processively into small peptides before commencing cleavages of another protein chain. Here, we present structural and biochemical evidence demonstrating that processive substrate degradation occurs at each of the six proteolytic active sites of Lon, which forms a deep groove that partially encloses the substrate polypeptide chain by accommodating only the unprimed residues and permits processive cleavage in the C-to-N direction.

Complete three-dimensional structures of the Lon protease translocating a protein substrate.

Lon is an evolutionarily conserved proteolytic machine carrying out a wide spectrum of biological activities by degrading misfolded damaged proteins and specific cellular substrates. Lon contains a large N-terminal domain and forms a hexameric core of fused adenosine triphosphatase and protease domains. Here, we report two complete structures of Lon engaging a substrate, determined by cryo–electron microscopy to 2.

Molecular basis for ATPase-powered substrate translocation by the Lon AAA+ protease.

The Lon AAA+ (adenosine triphosphatases associated with diverse cellular activities) protease (LonA) converts ATP-fuelled conformational changes into sufficient mechanical force to drive translocation of a substrate into a hexameric proteolytic chamber. To understand the structural basis for the substrate translocation process, we determined the cryo-electron microscopy (cryo-EM) structure of Meiothermus taiwanensis LonA (MtaLonA) in a substrate-engaged state at 3.6 Å resolution.

Molecular insights into substrate recognition and discrimination by the N-terminal domain of Lon AAA+ protease.

The Lon AAA+ protease (LonA) is a ubiquitous ATP-dependent proteolytic machine, which selectively degrades damaged proteins or native proteins carrying exposed motifs (degrons). Here we characterize the structural basis for substrate recognition and discrimination by the N-terminal domain (NTD) of LonA. The results reveal that the six NTDs are attached to the hexameric LonA chamber by flexible linkers such that the formers tumble independently of the latter.

Evolution of pulmonary valve reconstruction with focused review of expanded polytetrafluoroethylene handmade valves.

Objectives: Many surgeons develop unique techniques for unmet needs for right ventricular outflow reconstruction to resolve pulmonary regurgitation after corrective surgery for congenital heart diseases. Expanded polytetrafluoroethylene (ePTFE) stands out as a reliable synthetic material, and clinical results with handmade ePTFE valves have been promising. This review focuses on the historical evolution of the use of ePTFE in pulmonary valve replacement and in the techniques for pioneering the translation of the handmade ePTFE trileaflet design for the transcatheter approach.

Outflow tract geometries are associated with adverse outcome indicators in repaired tetralogy of Fallot.

Objectives: A wide variety of right ventricular outflow tract (RVOT) and pulmonary artery (PA) geometries has been reported in patients with repaired tetralogy of Fallot (rTOF). We aimed to investigate the associations between RVOT/PA geometries and outcome indicators in a large rTOF cohort receiving non-conduit repair.

Methods: Three-dimensional magnetic resonance angiographic images of 206 patients with rTOF who had a pulmonary regurgitation (PR) fraction ≥20% were reviewed.

In vitro study of trileaflet polytetrafluoroethylene conduit and its valve-in-valve transformation.

Objectives: Handmade trileaflet expanded polytetrafluoroethylene valved conduit developed using the flip-over method has been tailored for pulmonary valve reconstruction with satisfactory outcomes. We investigated the in vitro performance of the valve design in a mock circulatory system with various conduit sizes. In our study, the design was transformed into a transcatheter stent graft system which could fit in original valved conduits in a valve-in-valve fashion.

Structural Basis for the Differential Regulatory Roles of the PDZ Domain in C-Terminal Processing Proteases.

Carboxyl (C)-terminal processing proteases (CTPs) participate in protective and regulatory proteolysis in bacteria. The PDZ domain is central to the activity of CTPs but plays inherently different regulatory roles. For example, the PDZ domain inhibits the activity of the signaling protease CtpB by blocking the active site but is required for the activation of Prc (or Tsp), a tail-specific protease that degrades SsrA-tagged proteins.

Prenatal diagnosis of coarctation of the aorta with ventricular septal defect: A case report.

Objective: To present an accurate prenatal diagnosis of coarctation of the aorta with ventricular septal defect and to illustrate how early diagnosis in prenatal period with proper referral and counseling can optimize management.

Case Report: A case with coarctation of the aorta with ventricle septal defect was found to have an abnormal three vessel view at 12 weeks, and with close follow-ups, coarctation of the aorta with ventricle septal defect was diagnosed at 24 weeks. Following the support from a multidisciplinary team that provided counseling, diagnosis, and follow-ups, the pregnant woman decided to continue with the pregnancy and had a vaginal delivery at a medical center.

Structural basis of adaptor-mediated protein degradation by the tail-specific PDZ-protease Prc.

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.

Surgical Strategy Toward Biventricular Repair for Severe Ebstein Anomaly in Neonates and Infancy.

Background: Neonates with severe forms of Ebstein anomaly present a surgical challenge, and the Starnes operation as single ventricle palliation is highly advocated. Cone reconstruction for tricuspid valvuloplasty (TVP) has become a widely accepted technique, although very few cases of TVP have been reported in neonates. This report describes a surgical strategy for neonatal Ebstein anomaly, with an aim toward biventricular repair.

The Concept of the Arch Window in the Spiral Switch of the Great Arteries.

When the arterial switch operation includes the Lecompte maneuver, the arterial trunks are reconnected in parallel, rather than the spiral fashion observed in the normal heart. Thus, although the ventriculo-arterial connections are hemodynamically corrected, the anatomic arrangement cannot be considered normal. We hypothesized that, if feasible, it would be advantageous to restore a spiral configuration for the arterial trunks.

Outcome of Tricuspid Valve Plasty in Norwood Stage I Operation.

Background: Significant tricuspid valve regurgitation (TR) is considered a poor prognosis factor for patients with hypoplastic left heart syndrome (HLHS). Performing a tricuspid valve plasty (TVP) during Norwood Stage I palliation (S1P) has rarely been reported. We report mid-term results of performing TVP during Norwood S1P.

Structural Basis for the Magnesium-Dependent Activation and Hexamerization of the Lon AAA+ Protease.

The Lon AAA+ protease (LonA) plays important roles in protein homeostasis and regulation of diverse biological processes. LonA behaves as a homomeric hexamer in the presence of magnesium (Mg(2+)) and performs ATP-dependent proteolysis. However, it is also found that LonA can carry out Mg(2+)-dependent degradation of unfolded protein substrate in an ATP-independent manner.

Structural Insights into the Allosteric Operation of the Lon AAA+ Protease.

The Lon AAA+ protease (LonA) is an evolutionarily conserved protease that couples the ATPase cycle into motion to drive substrate translocation and degradation. A hallmark feature shared by AAA+ proteases is the stimulation of ATPase activity by substrates. Here we report the structure of LonA bound to three ADPs, revealing the first AAA+ protease assembly where the six protomers are arranged alternately in nucleotide-free and bound states.