Perceptions of pediatric deceased donor consent: A survey of organ procurement organizations.

BACKGROUND: Children awaiting transplantation face a high risk of waitlist mortality due to a shortage of pediatric organ donors. Pediatric donation consent rates vary across Organ Procurement Organizations (OPOs), suggesting that some OPOs might utilize more effective pediatric-focused donor recruitment techniques than others. An online survey of 193 donation requestor staff sheds light on the strategies that OPO staff utilize when approaching potential pediatric deceased organ donors. METHODS: In collaboration with the Association of Organ Procurement Organizations, the research team contacted the executive directors and medical directors of all 57 of the OPOs in the US. Of these, 51 OPOs agreed to participate, and 47 provided contact information for donation requestor staff. Of the 379 staff invited to participate in the survey, 193 provided complete responses. RESULTS: Respondents indicated more comfort approaching adult donors than pediatric donors, and they endorsed approach techniques that were interpersonal and emotional rather than professional and informative. Respondents were accurate in their perceptions about which donor characteristics are associated with consent. However, respondents from OPOs with high consent rates (according to data from the Scientific Registry of Transplant Recipients), and those from OPOs with low consent rates were very similar in terms of demographics, training, experience, and reported techniques. CONCLUSIONS: Additional research is needed to better determine why some OPOs have higher consent rates than others and whether the factors that lead to high consent rates in high-performing OPOs can be successful when implemented by lower-performing OPOs.

Tistrellabactins A and B Are Photoreactive C-Diazeniumdiolate Siderophores from the Marine-Derived Strain Tistrella mobilis KA081020-065.

The C-diazeniumdiolate group in the amino acid graminine is emerging as a new microbially produced Fe(III) coordinating ligand in siderophores, which is photoreactive. While the few siderophores reported from this class have only been isolated from soil-associated microbes, here we report the first C-diazeniumdiolate siderophores tistrellabactins A and B, isolated from the bioactive marine-derived strain Tistrella mobilis KA081020-065. The structural characterization of the tistrellabactins reveals unique biosynthetic features including an NRPS module iteratively loading glutamine residues and a promiscuous adenylation domain yielding either tistrellabactin A with an asparagine residue or tistrellabactin B with an aspartic acid residue at analogous positions. Beyond the function of scavenging Fe(III) for growth, these siderophores are photoreactive upon irradiation with UV light, releasing the equivalent of nitric oxide (NO) and an H atom from the C-diazeniumdiolate group. Fe(III)-tistrellabactin is also photoreactive, with both the C-diazeniumdiolate and the ß-hydroxyaspartate residues undergoing photoreactions, resulting in a photoproduct without the ability to chelate Fe(III).

On the origin of amphi-enterobactin fragments produced by Vibrio campbellii species.

Amphi-enterobactin is an amphiphilic siderophore isolated from a variety of microbial Vibrio species. Like enterobactin, amphi-enterobactin is a triscatecholate siderophore; however, it is framed on an expanded tetralactone core comprised of four L-Ser residues, of which one L-Ser is appended by a fatty acid and the remaining L-Ser residues are appended by 2,3-dihydroxybenzoate (DHB). Fragments of amphi-enterobactin composed of 2-Ser-1-DHB-FA and 3-Ser-2-DHB-FA have been identified in the supernatant of Vibrio campbellii species. The origin of these fragments has not been determined, although two distinct isomers could exist for 2-Ser-1-DHB-FA and three distinct isomers could exist for 3-Ser-2-DHB-FA. The fragments of amphi-enterobactin could originate from hydrolysis of the amphi-enterobactin macrolactone, or from premature release due to an inefficient biosynthetic pathway. Unique masses in the tandem MS analysis establish that certain fragments isolated from the culture supernatant must originate from hydrolysis of the amphi-enterobactin macrolactone, while others cannot be distinguished from premature release during biosynthesis or hydrolysis of amphi-enterobactin.

Ruckerbactin Produced by Yersinia ruckeri YRB Is a Diastereomer of the Siderophore Trivanchrobactin Produced by Vibrio campbellii DS40M4.

The Gram-negative bacterium Yersinia ruckeri is the causative agent for enteric red mouth disease in salmonids. The genome of Y. ruckeri YRB contains a biosynthetic gene cluster encoding the biosynthesis of catechol siderophores that are diastereomeric with the known vanchrobactin class of siderophores, (DHBDArgLSer)(1-3). Ruckerbactin (1), produced by Y. ruckeri YRB, was found to be the linear tris-l-serine ester composed of l-arginine and 2,3-dihydroxybenzoic acid, (DHBLArgLSer)3. The biscatechol, (DHBLArgLSer)2 (2), and monocatechol, DHBLArgLSer (3), compounds were also isolated and characterized. The macrolactone of ruckerbactin was not detected. The presence of LArg in ruckerbactin makes it the diastereomer of trivanchrobactin with DArg. The electronic circular dichroism spectra of Fe(III)-ruckerbactin and Fe(III)-trivanchrobactin reveal the opposite enantiomeric configurations at the Fe(III) sites. Fe(III)-ruckerbactin adopts the Δ configuration, and Fe(III)-trivanchrobactin adopts the Λ configuration. Y. ruckeri YRB was also found to produce the antimicrobial agent holomycin (4).

Genomic analysis of siderophore ß-hydroxylases reveals divergent stereocontrol and expands the condensation domain family.

Genome mining of biosynthetic pathways streamlines discovery of secondary metabolites but can leave ambiguities in the predicted structures, which must be rectified experimentally. Through coupling the reactivity predicted by biosynthetic gene clusters with verified structures, the origin of the ß-hydroxyaspartic acid diastereomers in siderophores is reported herein. Two functional subtypes of nonheme Fe(II)/α-ketoglutarate-dependent aspartyl ß-hydroxylases are identified in siderophore biosynthetic gene clusters, which differ in genomic organization-existing either as fused domains (IßHAsp) at the carboxyl terminus of a nonribosomal peptide synthetase (NRPS) or as stand-alone enzymes (TßHAsp)-and each directs opposite stereoselectivity of Asp ß-hydroxylation. The predictive power of this subtype delineation is confirmed by the stereochemical characterization of ß-OHAsp residues in pyoverdine GB-1, delftibactin, histicorrugatin, and cupriachelin. The l-threo (2S, 3S) ß-OHAsp residues of alterobactin arise from hydroxylation by the ß-hydroxylase domain integrated into NRPS AltH, while l-erythro (2S, 3R) ß-OHAsp in delftibactin arises from the stand-alone ß-hydroxylase DelD. Cupriachelin contains both l-threo and l-erythro ß-OHAsp, consistent with the presence of both types of ß-hydroxylases in the biosynthetic gene cluster. A third subtype of nonheme Fe(II)/α-ketoglutarate-dependent enzymes (IßHHis) hydroxylates histidyl residues with l-threo stereospecificity. A previously undescribed, noncanonical member of the NRPS condensation domain superfamily is identified, named the interface domain, which is proposed to position the ß-hydroxylase and the NRPS-bound amino acid prior to hydroxylation. Through mapping characterized ß-OHAsp diastereomers to the phylogenetic tree of siderophore ß-hydroxylases, methods to predict ß-OHAsp stereochemistry in silico are realized.

Patients and their family members prioritize post-transplant survival over waitlist survival when considering donor hearts for transplantation.

Heart transplant providers often focus on post-transplant outcomes when making donor decisions, potentially at the expense of higher waitlist mortality. This study aimed to assess public opinion regarding the selection of donor hearts and the balance between pre- and post-transplant risk. The authors generated a survey to investigate public opinion regarding donor acceptance. The survey was shared freely online across social media platforms in April-May 2019. A total of 718 individuals responded to the survey, with an equal distribution between patients and family members. Respondents consistently favored post-transplant outcomes over waitlist outcomes. About 83.9% of respondents favored a hospital with longer waitlist times, worse waitlist outcomes, but excellent post-transplant survival over a hospital with short waitlist times, a high waitlist survival, and inferior post-transplant survival. This preference was no different between pediatric and adult populations (P = .7), patient and family members (P = .935), or those with a pre- vs post-transplant perspective (P = .985). Patients and their family members consistently favor improved post-transplant survival over waitlist survival when considering the risks of accepting a donor organ. These findings suggest that current practice patterns of donor selection align with the opinions of patients and family members with heart failure or who have undergone heart transplantation.

Behavioral economics-A framework for donor organ decision-making in pediatric heart transplantation.

The high discard rate of pediatric donor hearts presents a major challenge for children awaiting heart transplantation. Recent literature identifies several factors that contribute to the disparities in pediatric donor heart usage, including regulatory oversight, the absence of guidelines on pediatric donor heart acceptance, and variation among transplant programs. However, a likely additional contributor to this issue are the behavioral factors influencing transplant team decisions in donor offer scenarios, a topic that has not yet been studied in detail. Behavioral economics and decision psychology provide an excellent foundation for investigating decision-making in the pediatric transplant setting, offering key insights into the behavior of transplant professionals. We conducted a systematic review of published literature in pediatric heart transplant related to behavioral economics and the psychology of decision-making. In this review, we draw on paradigms from these two domains in order to examine how existing aspects of the transplant environment, including regulatory oversight, programmatic variation, and allocation systems, may precipitate potential biases surrounding donor offer decisions. Recognizing how human decision behavior influences donor acceptance is a first step toward improving utilization of potentially viable pediatric donor hearts.

Impact of Molecular Architecture and Adsorption Density on Adhesion of Mussel-Inspired Surface Primers with Catechol-Cation Synergy.

Marine mussels secrete proteins rich in residues containing catechols and cationic amines that displace hydration layers and adhere to charged surfaces under water via a cooperative binding effect known as catechol-cation synergy. Mussel-inspired adhesives containing paired catechol and cationic functionalities are a promising class of materials for biomedical applications, but few studies address the molecular adhesion mechanism(s) of these materials. To determine whether intramolecular adjacency of these functionalities is necessary for robust adhesion, a suite of siderophore analog surface primers was synthesized with systematic variations in intramolecular spacing between catechol and cationic functionalities. Adhesion measurements conducted with a surface forces apparatus (SFA) allow adhesive failure to be distinguished from cohesive failure and show that the failure mode depends critically on the siderophore analog adsorption density. The adhesion of these molecules to muscovite mica in an aqueous electrolyte solution demonstrates that direct intramolecular adjacency of catechol and cationic functionalities is not necessary for synergistic binding. However, we show that increasing the catechol-cation spacing by incorporating nonbinding domains results in decreased adhesion, which we attribute to a decrease in the density of catechol functionalities. A mechanism for catechol-cation synergy is proposed based on electrostatically driven adsorption and subsequent binding of catechol functionalities. This work should guide the design of new adhesives for binding to charged surfaces in saline environments.

Comparison of a high throughput day case atrial fibrillation ablation service in a local hospital with standard regional tertiary cardiac centre care.

AIMS: We investigated safety and efficacy of a high throughput atrial fibrillation (AF) ablation service within a local non-cardiac centre compared with matched patients at the regional tertiary cardiac centre. METHODS AND RESULTS: Patients were consented in clinic and pre-assessed by clerical staff. Locally, other than physicians, staff had no experience of ablation and were trained with simulations. Pulmonary vein isolation (PVI) was performed with conscious sedation, on uninterrupted anticoagulation for at least 4 weeks. No transoesophageal echocardiogram (TOE) was performed. A 28 mm Arctic Front Advance Cryoballoon was used. A 20 mm Achieve wire demonstrated PVI on a portable laptop-based EP recording system. Phrenic nerve function was monitored during right PVI. Finally, a transthoracic echocardiogram excluded a pericardial effusion. A Femostop was applied. Two hundred and seventy-six patients were matched. Average age was 61 ± 0.7 years, 39% female. CHA2DS2 VASc score varied from 0 to 7. Procedure time was significantly shorter at the local hospital (63.5 ± 1.1 vs. 101.7 ± 2.9 min, P < 0.0001). Fluoroscopy time (5.5 ± 0.2 vs. 12.6 ± 0.6 min, P < 0.0001) and fluoroscopy dose were lower (17.2 ± 2.1 vs. 97.6 ± 14.6 mGy, P < 0.0001). Successful PVI was achieved in all. The complication rate was low (5.4% vs. 6.3%, P = not significant). Four (1.4%) patients were not day case discharges. At 3 month follow-up, 54.3% had complete resolution, and 26.1% had improvement of symptoms. A total of 16.6% patients requested repeat procedures for ongoing symptoms. CONCLUSION: In experienced hands, cryoballoon for paroxysmal AF is delivered safely and effectively in a local centre. Outcomes remain excellent. These short, day case procedures allow utilization of non-cardiac centres. The service provides a model to meet increasing demands.

Ambiguity of NRPS Structure Predictions: Four Bidentate Chelating Groups in the Siderophore Pacifibactin.

Identified through a bioinformatics approach, a nonribosomal peptide synthetase gene cluster in Alcanivorax pacificus encodes the biosynthesis of the new siderophore pacifibactin. The structure of pacifibactin differs markedly from the bioinformatic prediction and contains four bidentate metal chelation sites, atypical for siderophores. Genome mining and structural characterization of pacifibactin is reported herein, as well as characterization of pacifibactin variants accessible due to a lack of adenylation domain fidelity during biosynthesis. A spectrophotometric titration of pacifibactin with Fe(III) and 13C NMR spectroscopy of the Ga(III)-pacifibactin complex establish 1:1 metal:pacifibactin coordination and reveal which of the bidentate binding groups are coordinated to the metal. The photoreaction of Fe(III)-pacifibactin, resulting from Fe(III) coordination of the ß-hydroxyaspartic acid ligands, is reported.

ß-Hydroxyaspartic acid in siderophores: biosynthesis and reactivity.

A growing number of siderophores are found to contain ß-hydroxyaspartic acid (ß-OH-Asp) as a functional group for Fe(III) coordination, along with the more common catechol and hydroxamic acid groups. This review covers the structures, biosynthesis, and reactions of peptidic ß-OH-Asp siderophores. Hydroxylation of Asp in siderophore biosynthesis is predicted to be carried out either through discrete aspartyl ß-hydroxylating enzymes or through hydroxylating domains within non-ribosomal peptide synthetases, both of which display sequence homology to known non-heme iron(II), α-ketoglutarate-dependent dioxygenases. Ferric complexes of ß-OH-Asp siderophores are photoreactive, resulting in reduction of Fe(III) and oxidative cleavage of the siderophore to yield distinct types of photoproducts. Probing the photoreactivity of synthetic Fe(III)-α-hydroxycarboxylate clusters yields mechanistic insights into the different photoproducts observed for ß-OH-Asp and other α-hydroxycarboxylate siderophore Fe(III) complexes.

Correction to: Amphi­enterobactin commonly produced among Vibrio campbellii and Vibrio harveyi strains can be taken up by a novel outer membrane protein FapA that also can transport canonical Fe(III)­enterobactin.

In the original publication, third author's name was incorrectly published as Aneta L. Jelowicki.

Amphi-enterobactin commonly produced among Vibrio campbellii and Vibrio harveyi strains can be taken up by a novel outer membrane protein FapA that also can transport canonical Fe(III)-enterobactin.

Vibrio campbellii BAA-1116 (formerly Vibrio harveyi) is a model organism for quorum sensing study and produces the siderophores anguibactin and amphi-enterobactin. This study examined the mechanisms and specificity of siderophore uptake in V. campbellii and V. harveyi, and surveyed the diversity of siderophore production in V. campbellii and V. harveyi strains. The amphi-enterobactin gene cluster of BAA-1116 harbors a gene, named fapA, that is a homologue of genes encoding Fe(III)-siderophore-specific outer membrane receptors. Another strain, V. campbellii HY01, a strain pathogenic to shrimp, also carries this cluster including fapA. Our siderophore bioassay results using HY01-derived indicator strains show that the FapA protein localized in the outer membrane fraction of V. campbellii HY01 is essential for the uptake of Fe(III)-amphi-enterobactin as well as exogenous siderophores, including enterobactin from E. coli, but not vanchrobactin from V. anguillarum RV22 while Fe(III)-amphi-enterobactin can be utilized by V. anguillarum. Electrospray ionization mass spectrometry as well as bioassay revealed that various V. campbellii and V. harveyi strains produce a suite of amphi-enterobactins with various fatty acid appendages, including several novel amphi-enterobactins, and these amphi-enterobactins can be taken up by V. campbellii HY01 via FapA, indicating that amphi-enterobactin production is a common phenotype among V. campbellii and V. harveyi, whereas our previous work, confirmed herein, showed that anguibactin is only produced by V. campbellii strains. These results along with the additional finding that a 2,3-dihydroxybenzoic acid biosynthesis gene, aebA, located in the amphi-enterobactin gene cluster, is essential for both anguibactin and amphi-enterobactin biosynthesis, suggest the possibility that amphi-enterobactin is a native siderophore of V. campbellii and V. harveyi, while the anguibactin system has been acquired by V. campbellii during evolution.

Province-wide Biliary Atresia Home Screening Program in British Columbia: Evaluation of First 2 Years.

BACKGROUND AND OBJECTIVES: Biliary atresia (BA), a rare newborn liver disease, is the leading cause of liver-related death in children. Early disease recognition and timely surgical Kasai hepatoportoenterostomy (KP) offers long-term survival without liver transplant. Universal BA screening in Taiwan using infant stool color cards (ISCCs) has proven effectiveness. We report our experience with infant stool color card (ISCC) BA screening in a province-wide program in British Columbia (BC). The objective of this study is to assess program performance and cost from launch April 1, 2014 to March 31, 2016. METHODS: ISCCs distributed to families upon maternity ward discharge. Parents were instructed to monitor their infant's stool color for 1 month and contacted the screening center with concerns. The number of live births, ISCC distribution, BA cases, and costs were recorded. Cases with Program screen success had both acholic stool recognition (ISCC screen success) and timely referral for BA. RESULTS: All 126 maternity units received ISCCs. Of 87,583 live births there were 6 BA cases. Of the 5 cases with ISCC Screen Success 3 had Program Screen Success. The median KP age in the program screen success and failure groups was 49 (42-52) and 116 (49-184) days, respectively. Program sensitivity was 50%, specificity 99%, positive predictive value 4%, and negative predictive value 99%. A random sample of 1054 charts at BC Children's Hospital found an ISCC distribution rate of 94%. After a phase-in period, the annual program cost was $30,033.82, and the ISCC cost per birth was $0.68. CONCLUSIONS: The screening program has high specificity and distribution with low cost. Successful program case identification had earlier age at KP. Program modifications aim to improve sensitivity. Longer-term studies will determine program impact on health outcomes.

Siderophores and mussel foot proteins: the role of catechol, cations, and metal coordination in surface adhesion.

Metal coordination, hydrogen bonding, redox reactions, and covalent crosslinking are seemingly disparate chemical and physicochemical processes that are all accomplished in natural materials by the catechol functional group. This review focuses on the reactivity of catechols in tris-2,3-dihydroxybenzoyl-containing microbial siderophores and synthetic analogs, as well as Dopa-(3,4-dihydroxyphenylalanine)-containing mussel foot proteins that adhere to surfaces in aqueous conditions. Mussel foot proteins with a high content of Dopa and cationic amino acids, Lys and Arg, adhere strongly to mica, an aluminosilicate mineral, in aqueous conditions. The siderophore cyclic trichrysobactin, tris-(2,3-dihydroxybenzoyl-D-Lys-L-Ser) and related synthetic analogs in which the tri-Ser macrolactone is replaced by Tren, tris-(2-aminoethyl)amine, also adheres strongly to mica. Variation in the nature of the catechol and cationic groups in synthetic analogs reveals a synergism between the cationic amino acid and the catechol, required for strong aqueous adhesion. Autoxidation and iron(III)-catalyzed oxidation of 2,3-dihydroxy and 3,4-dihydroxy catechols are also considered. These siderophore analogs provide a platform to understand catechol interactions and reactivity on surfaces, which may ultimately improve the design of synthetic materials that address diverse challenges in medicine, materials science, as well as other disciplines, in which surface adhesion in aqueous conditions is important.

Defining the Catechol-Cation Synergy for Enhanced Wet Adhesion to Mineral Surfaces.

Mussel foot proteins (Mfps) exhibit remarkably adaptive adhesion and bridging between polar surfaces in aqueous solution despite the strong hydration barriers at the solid-liquid interface. Recently, catechols and amines-two functionalities that account for >50 mol % of the amino acid side chains in surface-priming Mfps-were shown to cooperatively displace the interfacial hydration and mediate robust adhesion between mineral surfaces. Here we demonstrate that (1) synergy between catecholic and guanidinium side chains similarly promotes adhesion, (2) increasing the ratio of cationic amines to catechols in a molecule reduces adhesion, and (3) the catechol-cation synergy is greatest when both functionalities are present within the same molecule.

The Canadian Biliary Atresia Registry: Improving the care of Canadian infants with biliary atresia.

Biliary atresia is the most common cause of end-stage liver disease and liver cirrhosis in children, and the leading indication for liver transplantation in the paediatric population. There is no cure for biliary atresia; however, timely diagnosis and early infant age at surgical intervention using the Kasai portoenterostomy optimize the prognosis. Late referral is a significant problem in Canada and elsewhere. There is also a lack of standardized care practices among treating centres in this country. Biliary atresia registries currently exist across Europe, Asia and the United States. They have provided important evidence-based information to initiate changes to biliary atresia care in their countries with improvements in outcome. The Canadian Biliary Atresia Registry was initiated in 2013 for the purpose of identifying best standards of care, enhancing public education, facilitating knowledge translation and advocating for novel national public health policy programs to improve the outcomes of Canadian infants with biliary atresia.

L'atrésie des voies biliaires est la principale cause d'insuffisance hépatique terminale et de cirrhose chez les enfants, et la première indication de transplantation du foie au sein de la population d'âge pédiatrique. Aucun traitement ne guérit l'atrésie des voies biliaires, mais un diagnostic rapide et le jeune âge du nourrisson au moment de l'intervention chirurgicale par hépato-porto-entérostomie de Kasai optimisent le pronostic. L'orientation tardive vers un spécialiste constitue un problème important au Canada et ailleurs. Par ailleurs, il n'existe pas de protocole de soins standardisés dans les centres de traitement du pays. On trouve des registres d'atrésie des voies biliaires en Europe, en Asie et aux États-Unis, lesquels ont fourni de l'information importante fondée sur des données probantes pour susciter des changements aux soins de cette affection dans ces pays et favoriser une amélioration des résultats. Le Registre canadien d'atrésie des voies biliaires a été créé en 2013 pour définir les meilleures normes de soins, améliorer l'éducation publique, favoriser le transfert des connaissances et prôner de nouveaux programmes de politiques en santé publique en vue d'améliorer le sort des nourrissons canadiens présentant une atrésie des voies biliaires.

Fatty acid hydrolysis of acyl marinobactin siderophores by Marinobacter acylases.

The marine bacteria Marinobacter sp. DS40M6 and Marinobacter nanhaiticus D15-8W produce a suite of acyl peptidic marinobactin siderophores to acquire iron under iron-limiting conditions. During late-log phase growth, the marinobactins are hydrolyzed to form the marinobactin headgroup with release of the corresponding fatty acid tail. The bntA gene, a homologue of the Pseudomonas aeruginosa pyoverdine acylase gene, pvdQ, was identified from Marinobacter sp. DS40M6. A bntA knockout mutant of Marinobacter sp. DS40M6 produced the suite of acyl marinobactins A-E, without the usual formation of the marinobactin headgroup. Another marinobactin-producing species, M. nanhaiticus D15-8W, is predicted to have two pvdQ homologues, mhtA and mhtB. MhtA and MhtB have 67% identical amino acid sequences. MhtA catalyzes hydrolysis of the apo-marinobactin siderophores as well as the quorum sensing signaling molecule, dodecanoyl-homoserine lactone. In contrast to hydrolysis of the suite of apo-marinobactins by MhtA, hydrolysis of the iron(III)-bound marinobactins was not observed.