Evolving Impact of COVID-19 on Transplant Center Practices and Policies in the United States

In our first survey of transplant centers in March 2020, >75% of kidney and liver programs were either suspended or operating under restrictions. To safely resume transplantation, we must understand the evolving impact of COVID-19 on transplant recipients and center-level practices. We therefore conducted a six-week follow-up survey May 7-15, 2020, and linked responses to the COVID-19 incidence map, with a response rate of 84%. Suspension of live donor transplantation decreased from 72% in March to 30% in May for kidneys and from 68% to 52% for livers. Restrictions/suspension of deceased donor transplantation decreased from 84% to 58% for kidneys and from 73% to 42% for livers. Resuming transplantation at normal capacity was envisioned by 83% of programs by August 2020. Exclusively using local recovery teams for deceased donor procurement was reported by 28%. Respondents reported caring for a total of 1166 COVID-19–positive transplant recipients; 25% were critically ill. Telemedicine challenges were reported by 81%. There was a lack of consensus regarding management of potential living donors or candidates with SARS-CoV-2. Our findings demonstrate persistent heterogeneity in center-level response to COVID-19 even as transplant activity resumes, making ongoing national data collection and real-time analysis critical to inform best practices.     

Neuroimaging manifestations and genetic heterogeneity of Walker-Warburg syndrome in Saudi patients

BackgroundWalker-Warburg syndrome (WWS), an autosomal recessive disease, is the most severe phenotype of congenital muscular dystrophies. Its diagnosis remains primarily clinical and radiological. Identification of its causative variants will assist genetic counseling. We aim to describe genetic and neuroimaging findings of WWS and investigate the correlation between them.MethodsWe retrospectively reviewed the clinical, genetic and neuroimaging findings of eleven Saudi neonates diagnosed with WWS between April 2012 and December 2018 in a single tertiary care center. Correlation between neuroimaging and genetic findings was investigated.ResultsAll patients had macrocephaly except one who had intrauterine growth restriction. Dysmorphic features were identified in nearly half of the patients. Creatine kinase levels were available in nine patients and were always elevated. Homozygous pathogenic variants were identified in all patients spanning POMT1 (n = 5), TMEM5 (n = 3), ISPD (n = 2) and POMT2 (n = 1) including one patient who had a dual molecular diagnosis of ISPD and PGAP2. On neuroimaging, all patients showed cobblestone cortex, classical infratentorial findings, and hydrocephalus. Other cerebral cortical malformations included subependymal heterotopia, polymicrogyria and open-lip schizencephaly in four, two and one patients, respectively. Buphthalmos and microphthalmia were the most prevalent orbital findings and found in all patients either unilaterally or bilaterally.ConclusionWWS is a genetically heterogeneous disorder among Saudis. The case with an additional PGAP2-related phenotype exemplifies the increased risk of dual autosomal recessive disorders in consanguineous populations. MRI is excellent in demonstrating spectrum of WWS brain and orbital malformations; however, no definite correlation could be found between the MRI findings and the genetic variant.     

Nitroxide‐Mediated Radical Polymerization of N‐tert‐Butylacrylamide

The nitroxide‐mediated polymerization of N‐tert‐butylacrylamide (TBAM) in DMF at 120 °C using SG1/DEPN and AIBN has been investigated. Linear growth in number‐average molecular weight ( ) versus conversion and narrow molecular weight distributions (MWDs) with high livingness were obtained up to ≈8 000 g · mol^?1. For higher molecular weights, the MWDs gradually became broader with low molecular weight tailing, and deviated downwards from theoretical values. Quantitative analyses of MWDs, along with specifically designed conventional radical polymerizations at 120 °C, were consistent with chain transfer to monomer limiting the attainable . This finding can be equally applied to existing literature polymerizations of TBAM.