Differential Eye Expression of Xenopus Acyltransferase Gnpat and Its Biochemical Characterization Shed Light on Lipid-Associated Ocular Pathologies.

Purpose: Plasmalogens (Plgs) are highly abundant lipids in the retina, and their deficiency leads to severe abnormalities during eye development. The first acylation step in the synthesis of Plgs is catalyzed by the enzyme glyceronephosphate O-acyltransferase (GNPAT), which is also known as dihydroxyacetone phosphate-acyltransferase (EC 2.3.1.42). GNPAT deficiency produces rhizomelic chondrodysplasia punctata type 2, a genetic disorder associated with developmental ocular defects. Despite the relevance of retinal Plgs, our knowledge of the mechanisms that regulate their synthesis, and the role of GNPAT during eye development is limited. Methods: Using the Xenopus laevis model organism, we characterized by in situ hybridization the expression pattern of gnpat and compared it to glycerol 3-phosphate acyltransferase mitochondrial (gpam or gpat1) during eye neurogenesis, lamination, and morphogenesis. The Xenopus Gnpat was biochemically characterized in a heterologous expression system in yeast. Results: During development, gnpat is expressed in proliferative cells of the retina and lens, and post-embryogenesis in proliferative cells of the ciliary marginal zone and lens epithelium. In contrast, gpam expression is mainly restricted to photoreceptors. Xenopus Gnpat expressed in yeast is present in both soluble and membrane fractions, but only the membrane-bound enzyme displays activity. The amino terminal of Gnpat, conserved in humans, shows lipid binding capacity that is enhanced by phosphatidic acid. Conclusions: Enzymes involved in the Plgs and glycerophospholipid biosynthetic pathways are differentially expressed during eye morphogenesis. The gnpat expression pattern and the molecular determinants regulating Gnpat activity advance our knowledge of this enzyme, contributing to our understanding of the retinal pathophysiology associated with GNPAT deficiency.

The HeartMate 3 left ventricular assist device as a strategy to bridge to transplant.

PURPOSE: Recent changes in the market for left ventricular assist devices have resulted in the HeartMate 3 (HM3) being the only commercially-available device. This study evaluates the outcomes of patients with a HM3 waitlisted for and undergoing orthotopic heart transplantation (OHT). METHODS: Patients waitlisted for isolated OHT with a HM3 or undergoing OHT after bridge-to-transplant (BTT) with a HM3 between 2015 and 2021 were identified from the UNOS registry and included in this study. Propensity matching was used to compare outcomes of BTT-HM3 versus primary OHT. RESULTS: A total of 1321 patients supported with a HM3 underwent OHT during our study period. Unadjusted 30-day, 90-day, and 1-year survival following OHT in the BTT-HM3 cohort was 96.5%, 94.4%, and 90.7%, respectively. In propensity-matched analysis, 1103 BTT-HM3 patients were compared with 1103 primary OHT patients. Rates of post-OHT stroke were higher in the BTT-HM3 group (4.4% vs. 2.0%, p = .001). The BTT-HM3 group had lower 30-day survival (96.2% vs. 97.4%, p = .033) although 90-day (94.2% vs. 95.3%, p = .103) and 1-year survival (90.4% vs. 91.7%, p = .216) were comparable. A total of 1251 patients were supported with a HM3 at the time of OHT listing during the study period. At the time of this analysis, 60 (4.5%) remained on the waitlist, 991 (75.0%) underwent OHT, and 119 (9.0%) died or clinically deteriorated with waitlist removal. CONCLUSIONS: The HM3 is a viable method for BTT with acceptable waitlist outcomes. Although 1-year survival is comparable to primary OHT, early outcomes are worse, suggesting that refinement of patient selection and perioperative management is prudent to optimizing outcomes.

"Triple low" free-breathing CTPA protocol for patients with dyspnoea.

AIM: To assess the performance of a "triple-low" free-breathing protocol for computed tomography pulmonary angiography (CTPA) evaluated on patients with dyspnoea and suspected pulmonary embolism and discuss its application in routine clinical practice for the study of the pulmonary parenchyma and vasculature. MATERIAL AND METHODS: This study was conducted on a selected group of dyspnoeic patients referred for CTPA. The protocol was designed using fast free-breathing acquisition and a small, fixed volume (35 ml) of contrast agent in order to achieve a low-exposure dose. For each examination, radiodensity of the pulmonary trunk and ascending aorta, and the dose-length product (DLP) were recorded. A qualitative analysis was performed of pulmonary arterial enhancement and the pulmonary parenchyma. RESULTS: This study included 134 patients. Contrast enhancement of the pulmonary arteries (409 ± 159 HU) was systematically >250 HU. The duration of acquisition ranged from 0.9 to 1.3 seconds for free-breathing imaging. The mean DLP was in the range of low-dose chest CT acquisitions (145 ± 73 mGy·cm). The analysis was deemed optimal in 90% (120/134) of cases for the pulmonary parenchyma. Sixty-nine per cent (92/134) of cases demonstrated homogeneous enhancement of the pulmonary arteries to the subsegmental level. Only 6% (8/134) of examinations were considered uninterpretable. CONCLUSION: The present "triple-low" CTPA protocol allows convenient analysis of the pulmonary parenchyma and arteries without hindrance by respiratory motion artefacts in dyspnoeic patients.

How We Perform a David Procedure With an Upper Hemisternotomy Approach.

OBJECTIVE: Valve-sparing aortic root replacement (David procedure) is the technique of choice in appropriately selected patients with aortic root aneurysms. These procedures are seldom performed in a minimally invasive fashion. We describe our systematic approach to the David procedure using an upper hemisternotomy (UHS). Methods: Our method involves a J-type UHS exiting the right third or fourth intercostal space. Ascending aortic and femoral venous cannulation are performed using the Seldinger technique under transesophageal echocardiographic guidance. Between August 2005 and August 2014, 27 patients underwent an isolated elective David procedure using a full sternotomy (FS). Sixteen underwent an isolated elective UHS David procedure from May 2015 to February 2019. Perioperative safety outcomes were compared between the 2 cohorts. Results: The UHS and FS David cohorts were primarily male (87.5% and 85.2%, respectively) and 51 and 50 years old on average, respectively. Custodiol-histidine-tryptophan-ketoglutarate cardioplegia (93.8% vs 37.0%, P < 0.001) and Cor-Knot (100% vs 0%, P < 0.001) were used significantly more in the UHS David cohort. There were no significant differences in cardiopulmonary bypass (200 [183-208] vs 212 [183-223] min, P = 0.309) and aortic cross-clamp (169 [155-179] vs 188 [155-199] min, P = 0.128) times in the UHS and FS cohorts. There were no instances of hospital or 30-day mortality in either cohort. Intensive care unit and hospital stays were comparable between the 2 cohorts. Conclusions: The David procedure via UHS is a safe and reproducible technique for aortic root replacement.

The mini-Bentall approach: Comparison with full sternotomy.

BACKGROUND: The upper mini sternotomy Bentall (mini-Bentall) procedure may result in less trauma and earlier recovery compared with the full sternotomy Bentall procedure (full Bentall). This study compares immediate and 1- and 3-year survival rates after mini- and full Bentall procedures. METHODS: Between February 2009 and July 2019, 48 patients underwent a mini-Bentall and 49 underwent a full Bentall. Patients who required concomitant procedures, reoperations, or hypothermic circulatory arrest were excluded from our analysis. The mean patient age was 60.7 years in the mini-Bentall group and 59.0 years in the full Bentall group. RESULTS: There were no in-hospital mortalities. The median cardiopulmonary bypass time (mini-Bentall: 165 minutes [interquartile range (IQR), 155.5-183 minutes]; full Bentall: 164 minutes [IQR, 150-187 minutes]; P = .619) and aortic cross-clamp times (139 minutes [IQR, 128.5-153 minutes] vs 137 minutes [IQR, 125-156 minutes]; P = .948) were not significantly different between the 2 groups. The mini-Bentall group had a significantly shorter median ventilation time compared with the full Bentall group (5.5 hours [IQR, 3-14 hours] vs 17 hours [IQR, 11-23 hours]; P < .001). None of the patients in the mini-Bentall group had postoperative bleeding necessitating reoperation, whereas 4 patients (8.2%) underwent reoperation after full Bentall (P = .043). The mini-Bentall group also had a shorter median hospital length of stay (6 days [IQR, 5-8 days] vs 7 days [IQR, 6-8 days]; P = .086). Survival at 1 and 3 years was 100% in both cohorts. CONCLUSIONS: Patients required significantly less ventilation time and reoperations for bleeding after the mini-Bentall procedure. There were no significant differences in cardiopulmonary bypass, aortic cross-clamp times, or intensive care unit and hospital length of stay between the mini-Bentall and full Bentall groups. The mini-Bentall approach is associated with low morbidity and mortality.

The impact of coronavirus 2019 on general surgery residency: A national survey of program directors.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has had a widespread impact on graduate medical education. This survey aims to assess how general surgery residency programs adapted to the initial wave of the COVID-19 pandemic in the United States (US). MATERIALS AND METHODS: General surgery program directors (PDs) in the US were invited to partake in a 16-question survey between April 17 and May 1, 2020. The survey included questions about basic program information, clinical practice changes, changes to education structure, surgery resident clinical duties, and perceived impact on resident operative experience and future career choices. RESULTS: Forty-eight PDs completed the survey in the designated two-week period. Almost all (44/48, 91.7%) programs changed their didactic education to an online video conference-based format. Thirteen programs (27.1%) decreased the amount/frequency of formal education, and 13 (27.1%) reported canceling didactic education for some period of time. The majority of PDs (26/48, 54.2%) felt these changes had no impact on resident didactic participation, 14 (29.2%) reported an increase in participation, and 8 (16.7%) reported decreased participation. Ten programs (20.8%) redeployed residents to non-surgical services at the time of this survey, 30 (62.5%) have not redeployed residents but plan to if needed, and 8 (16.7%) did not have any plans to redeploy residents. CONCLUSIONS: The outbreak of COVID-19 has required general surgery residency PDs to change numerous aspects of resident education and clinical roles. Future inquiry is needed to assess if these changes lead to appreciable differences in resident preparedness and career selection.

Giant coronary artery aneurysm in infantile Kawasaki disease: When to use cardiac computed tomography angiography.

Transthoracic echocardiography is the imaging modality of choice for the detection of coronary artery aneurysms (CAAs) in Kawasaki disease. However, cardiac computed tomography angiography is useful in the diagnosis of distal CAAs.

Left innominate vein creation using left internal jugular vein tunneled to right internal jugular vein.

BACKGROUND: Left innominate vein occlusion is a known complication of pacemaker and central venous catheter placement. For dialysis-dependent patients with an arteriovenous fistula (AVF), this can prevent successful hemodialysis and may require surgical intervention. CASE REPORT: An 8-month-old male was diagnosed with hemolytic uremic syndrome and became dialysis-dependent at 11 months of age. After multiple vascular access and peritoneal dialysis complications, the patient had construction of a brachiobasalic AVF in his left arm at 13 years old. While waiting for the AVF to mature, an attempt to remove a previously placed left subclavian vein port-a-cath was unsuccessful and a follow-up imaging revealed that the vessel had become occluded. The fistula remained patent, but due to arm swelling and venous obstruction, his fistula was not accessible. Multiple attempts to percutaneously cross the left innominate vein were unsuccessful and the patient was referred for surgical intervention. At 15 years old, the patient was taken to the operating room for transposition of the left internal jugular vein (LIJ) to the right internal jugular vein (RIJ). The LIJ was transected under the mandible and anastomosed to the RIJ. Subsequently the patient underwent VWING insertion rather than venous transposition for constant site dialysis. Although he has required frequent transcatheter dilation of the LIJ-RIJ anastomosis, the patient was successfully dialyzed using this fistula for 5 years. The patient received a cadaveric renal transplant at 5 years 20 days. CONCLUSIONS: In cases of left innominate vein stenosis, transposing the LIJ can create a new left innominate vein that can alleviate venous hypertension and preserve fistula function. This procedure avoids sternotomy and only requires one anastomosis.

Clinical Exposure to Cardiothoracic Surgery for Medical Students and General Surgery Residents.

BACKGROUND: The introduction of integrated 6-year cardiothoracic surgery (CTS) residency programs has shifted recruitment efforts to encompass not only general surgery (GS) residents, but also medical students. OBJECTIVE: The aim of this paper is to assess medical student and GS resident clinical exposure to CTS. DESIGN: Data from the Association of American Medical Colleges Visiting Student Application Service and the Accreditation Council for Graduate Medical Education Case Log Reports were collected from 2010 to 2017 and 2010 to 2018, respectively. The data extracted included medical students who applied and received an offer for elective rotations and the cases performed as a GS resident. RESULTS: A mean of 95 ± 28.5 medical students applied for CTS rotations annually and the applicants for CTS rotations increased by an average of 11.8% per year. However, significantly less students received an offer compared to other specialties (53.4% CTS vs 74.1% GS, 79.3% plastic surgery, 86.3% urology, 85.7% otolaryngology, 88.6% neurological surgery, and 89.6% orthopedic surgery) (p < 0.001). GS residents performed a mean of 39.3 ± 0.8 CTS procedures during residency: 32.9 ± 1.0 performed as a junior resident and 6.3 ± 0.7 as a chief resident. Out of all CTS procedures, 7.3% were cardiac procedures, with rates increasing from 5.6% to 8.4% during the study period (p = 0.001). CONCLUSIONS: Elective rotation opportunities in CTS are high in demand for medical students while GS residents receive limited CTS exposure, especially cardiac cases. Increasing clinical opportunities in both groups will aid in recruiting young talent to the field.

Adult congenital pulmonary valve insertion using a new bioprosthetic aortic valve: Inspiris.

We describe successful placement of the Inspiris Resilia aortic valve in the pulmonary position. This valve has advantages for immediate benefit and future percutaneous interventions, making it a promising prosthesis for adult congenital patients.

Why Teachers and Learners of Medicine Need Portraiture.

Medical and especially surgical teaching stresses the importance of careful observation, developing tolerance for ambiguity, and cultivating empathy for patients' and colleagues' experiences of receiving and giving health care. Portraiture is defined by portraitist Mark Gilbert as a collaborative process between subject and artist; sitting is as critical to this process as painting or drawing. This article draws upon the second author's work with Gilbert to examine how portraiture can motivate key teaching and learning goals in health professions education by facilitating learners' explorations of their own and others' biases, limitations, and approaches to gathering information from and about a source (eg, a subject or a patient).

Efficient approach to superior vena cava baffle stenosis following the Mustard procedure: Expanding the role of a mechanical rotating dilator sheath for lead extraction.

INTRODUCTION: In adult congenital patients with transposition of the great arteries originally treated with the Mustard (atrial switch) procedure, the most common reason for re-intervention is baffle stenosis. This may be exacerbated by permanent transvenous pacemaker lead placement across the baffle. CASE REPORT: A 47-year-old female status post Mustard procedure performed at 15 months old presented with a high-grade stenosis of the superior vena cava (SVC) baffle from the SVC to the left atrium, with a nonfunctional permanent pacemaker lead passing through the baffle. A mechanical rotating dilator sheath was used for attempted lead extraction, relieving the baffle stenosis almost completely as a secondary effect, before the placement of a 10 × 27 mm Visipro balloon-expandable stent in the SVC baffle. CONCLUSIONS: Use of the mechanical rotating dilator sheath is an evolving treatment strategy in adult congenital heart disease to minimize the risk of bleeding, trauma to surrounding structures, and death. Its ability to fully alleviate baffle stenosis even when full lead extraction is not feasible or is associated with significant procedural risk, further demonstrates its expanded role in this patient population. A multidisciplinary approach and great diligence must be employed to avoid potential complications.

Fontan procedure: Early outcomes of 87 consecutive patients in a tertiary care center.

Al Absi and colleagues report their early results of the Fontan procedure in 87 consecutive patients between August 2008 and July 2017 in a tertiary care hospital. The use of the intra/extracardiac fenestration is a promising modification because it is unlikely to be occluded by surrounding tissue and may be associated with decreased pleural effusions, length of hospital stay, and incidence of postoperative arrhythmias.

Nanocomposite structure of two-line ferrihydrite powder from total scattering.

Ferrihydrite is one of the most important iron-containing minerals on Earth. Yet determination of its atomic-scale structure has been frustrated by its intrinsically poor crystallinity. The key difficulty is that physically-different models can appear consistent with the same experimental data. Using X-ray total scattering and a nancomposite reverse Monte Carlo approach, we evaluate the two principal contending models-one a multi-phase system without tetrahedral iron(III), and the other a single phase with tetrahedral iron(III). Our methodology is unique in considering explicitly the complex nanocomposite structure the material adopts: namely, crystalline domains embedded in a poorly-ordered matrix. The multi-phase model requires unphysical structural rearrangements to fit the data, whereas the single-phase model accounts for the data straightforwardly. Hence the latter provides the more accurate description of the short- and intermediate-range order of ferrihydrite. We discuss how this approach might allow experiment-driven (in)validation of complex models for important nanostructured phases beyond ferrihydrite.

Qualitative and quantitative contrast-enhanced ultrasonography for the characterisation of non-palpable testicular tumours.

AIM: To assess the diagnostic performance of conventional ultrasound (US) and contrast-enhanced ultrasonography (CEUS) in the differential diagnosis of non-palpable intratesticular tumours. MATERIALS AND METHODS: The local ethics review board approved the protocol, and all of the patients provided written informed consent. Between December 2011 and February 2014, men with non-palpable testicular tumours and normal tumour markers who were referred for surgery were included. The tumours were analysed by conventional US, including B-mode and colour Doppler US (CDUS) as well as by CEUS. Morphological aspects and qualitative and quantitative CEUS criteria, based on visual enhancement and time-intensity curves, were assessed for each lesion. RESULTS: Forty patients were ultimately included. Based on histopathological results, the tumours were classified into three groups: benign tumours (n=16), malignant tumours (n=15), and burned-out tumours (n=9). In B-mode, the morphological aspects were significantly different between benign and malignant tumours (p-values from 0.0002 to 0.008). Qualitative and quantitative analyses of the CEUS images revealed that burned-out tumours exhibited significantly less enhancement than malignant and benign tumours: in burned-out tumours, time-intensity curves were flat, whereas in both benign and malignant tumours the curves had a bell-shaped pattern. All intensity parameters were lower for burned-out tumours compared to benign and malignant tumours (p-value from 0.0001 to 0.026). Both benign and malignant tumours enhanced strongly, however, and no significant difference between the two was noted (p-value from 0.0721 to 0.0953). CONCLUSION: Unlike conventional US, which enable benign lesions to be differentiated from malignant or burned-out tumours, CEUS failed to enabled differentiation between benign lesions and malignant vascularised testicular tumours. CEUS appears to have the potential, however, to differentiate burned-out tumours from vascularised testicular tumours.