Elucidating the structure and function of the nucleus-The NIH Common Fund 4D Nucleome program.

Genomic architecture appears to play crucial roles in health and a variety of diseases. How nuclear structures reorganize over different timescales is elusive, partly because the tools needed to probe and perturb them are not as advanced as needed by the field. To fill this gap, the National Institutes of Health Common Fund started a program in 2015, called the 4D Nucleome (4DN), with the goal of developing and ultimately applying technologies to interrogate the structure and function of nuclear organization in space and time.

Single-Pass Albumin Dialysis as Rescue Therapy for Pediatric Calcium Channel Blocker Overdose.

Calcium channel blocker ingestions remain one of the leading causes of death related to cardiovascular medication ingestion in both adults and pediatric patients. We report a case of a 17-year-old, 103 kg female presenting after an intentional polypharmacy ingestion, including 500 to 550 mg of amlodipine. She presented with profound vasoplegia and cardiovascular collapse requiring high-dose inotropes and eventual life support with extracorporeal membrane oxygenation (ECMO). Current available treatments, designed for adults, including lipid emulsion and methylene blue, provided no sustained clinical improvement. This resulted in the initiation of single-pass albumin dialysis (SPAD). We aim to describe the clinical implications, amlodipine toxic dose effects, and clinical challenges associated with large pediatric patients and high-dose medications. We also discuss several challenges encountered related to dosing and concentration of medications, which led to fluid overload. Given the ongoing obesity epidemic, we routinely see pediatric patients of adult size. This will continue to challenge pediatric use of adult dosing and concentrations to avoid excessive fluid administration for high-dose medications, such as insulin and vasoactive agents. To our knowledge, this is the first successful case of using SPAD in conjunction with ECMO for salvage therapy after refractory life-threatening calcium channel blocker toxicity.

Pregnancy associated TMA in 13-year-old patient successfully treated with Eculizumab: case report.

BACKGROUND: This report introduces an unusual cause of kidney failure in a previously healthy pediatric patient. She developed thrombotic microangiopathy (TMA) that was diagnosed post-partum, requiring dialysis and eculizumab, with eventual recovery of kidney function ([chronic kidney disease (CKD) stage 3]. CASE PRESENTATION: The patient was induced at term due to preeclampsia, with delivery complicated by severe postpartum hemorrhage from uterine atony. She continued to have severe hypertension post-delivery and further developed acute kidney injury (AKI) with decreased urinary output and respiratory distress requiring dialysis therapy. Labs revealed hemolysis with elevated lactate dehydrogenase, low haptoglobin, anemia, and thrombocytopenia, but otherwise unremarkable immunology labs. Once clinically stabilized the patient underwent kidney biopsy, which was consistent with TMA. Treatment was initiated with eculizumab, a monoclonal antibody for terminal complement blockade. Her clinical status improved (including markers of hemolysis and inflammation) with kidney replacement therapy and complement blockade. On discharge, she had increasing urine output and was prescribed 3 day per week hemodialysis and twice monthly eculizumab infusions. By 6 weeks post-delivery, hemodialysis was discontinued and her eculizumab was weaned to monthly infusions. Eculizumab was discontinued at 12 months postpartum. Genetic testing for mutations of the complement system was negative. The patient has residual stage 3 CKD with stable kidney function, requiring two agents for blood pressure control, including an ACE inhibitor for antiproteinuric effect. CONCLUSIONS: This case report showcases an unusual cause of renal failure in a pediatric patient due to TMA in the post-partum period. She required intermittent hemodialysis (iHD) for a brief period, however she was treated successfully with eculizumab that was able to be weaned off 1 year after delivery. She has residual stage 3 CKD and no further signs or symptoms of TMA.

Hypervitaminosis A in Pediatric Patients With Advanced Chronic Kidney Disease.

OBJECTIVE: Hypervitaminosis A is well-described but overlooked in chronic kidney disease (CKD) and has been associated with hypercalcemia, contributing to mineral bone disease. Our objective is to assess prevalence of hypervitaminosis A and its association with bone health in an advanced-CKD population. METHODS: We performed a retrospective review of 58 children with CKD 4-5 to examine the association between vitamin A levels and bone health and compared these values between a primarily formula-fed (FF) and nonprimarily formula-fed cohort (NFF). RESULTS: Fifty-six of 58 patients (97%) had hypervitaminosis A with a mean vitamin A level of 1,475 ± 597 mcg/dL. When compared with the upper limit of normal vitamin A level for age, the FF group's vitamin A level was 2.9x upper limit of normal and the NFF group's vitamin A level was 2.2x upper limit of normal (P = .02). The mean calcium level was 10.3 mg/dL in the FF group and 9.8 mg/dL in the NFF group (P = .057). Percent of patients lower than, within, or greater than goal parathyroid hormone range was statistically significant with 15 (62%) of the FF group lower than goal and 16 (72%) of the NFF cohort greater than goal (P = .006). CONCLUSIONS: We concluded vitamin A and calcium levels are higher in the FF versus the NFF population. FF patients are more likely to have parathyroid hormone levels lower than the goal range, placing them at risk for adynamic bone disease. We recommend monitoring vitamin A levels as part of routine nutritional assessments and dietary interventions to prevent hypervitaminosis A to improve bone health in late CKD.

Trends and Variation in Care and Outcomes for Children Hospitalized With Acute Gastroenteritis.

OBJECTIVES: Assess trends in inpatient acute gastroenteritis (AGE) management across children's hospitals and identify elements of AGE management associated with resource use. METHODS: We examined inpatient stays for children 6 months to 18 years hospitalized with AGE from 2009 to 2018 using the Pediatric Health Information System database. We characterized demographics, hospital-level resource use (ie, medications, laboratories, and imaging), and outcomes (ie, cost per case, 14-day revisit rates, and length of stay [LOS]). We compared demographic characteristics and resource use between 2009 to 2013 and 2014 to 2018 using χ2 and Wilcoxon rank-sum tests. We grouped hospitals on the basis of 2009 use of each resource and trended use over time using logistic regression. Annual change in mean cost and LOS were estimated by using models of log-transformed data. RESULTS: Across 32 354 hospitalizations at 38 hospitals, there was a high use of electrolyte testing (85.4%) and intravenous fluids (84.1%) without substantial changes over time. There were significant reductions in the majority of laboratory, medication, and imaging resources across hospitals over the study period. The most notable reductions were for rotavirus and stool testing. Many hospitals saw a decrease in LOS, with only 3 noting an increased revisit rate. Reductions in cost per case over time were most associated with decreases in imaging, laboratory testing, and LOS. CONCLUSIONS: Significant variation in resource use for children hospitalized with AGE coupled with high use of resources discouraged in AGE guidelines highlights potential opportunities to improve resource use that may be addressed in future AGE guidelines and quality improvement initiatives.

Composite Health Outcomes in Pediatric and Young Adult Kidney Transplant Recipients.

OBJECTIVE: To assess composite health outcomes in pediatric and young adult kidney transplant recipients following kidney transplantation. STUDY DESIGN: We conducted a cross-sectional study of all recipients at our center who had a 1-, 3-, 5-, and/or 10-year transplant anniversary visit between October 2008 and February 2015. The kidney transplant recipients were assessed at each time point according to an outcome measure consisting of 15 pass/fail criteria in 5 domains: allograft health, rejection and immunology, infection, cardiovascular health, and growth. RESULTS: We analyzed 148 patients at 231 transplantation anniversary visit time points; 52 of 82 (63%) patients assessed at 1 year had an ideal outcome, meeting at least 13 of the 15 criteria. This decreased to 37% at year 3, 40% at year 5, and 26% at year 10 (P < .01). The most common failures across all time points occurred in the domains of growth (43%-52% passing) and cardiovascular health (33%-51% passing). Allograft health declined significantly, decreasing from 74% at year 1 to 33% at year 10 (P < .01). The percentage of patients with graft failure increased from 2.4% at 1 year to 39.5% at 10 years (P < .01), and patient deaths increased from 0 to 11% (P < .01) in the same time frame. CONCLUSIONS: Ideal outcomes for pediatric kidney transplant recipients decrease over time with growth, cardiovascular health, and allograft health as the primary failure modes. Understanding the composite health of young recipients will allow primary care providers and nephrologists alike to evaluate the overall health of kidney transplant recipients and focus clinical care on the most common sequelae.

Structure of the Regulator of G Protein Signaling 8 (RGS8)-Gαq Complex: MOLECULAR BASIS FOR Gα SELECTIVITY.

Regulator of G protein signaling (RGS) proteins interact with activated Gα subunits via their RGS domains and accelerate the hydrolysis of GTP. Although the R4 subfamily of RGS proteins generally accepts both Gαi/o and Gαq/11 subunits as substrates, the R7 and R12 subfamilies select against Gαq/11. In contrast, only one RGS protein, RGS2, is known to be selective for Gαq/11. The molecular basis for this selectivity is not clear. Previously, the crystal structure of RGS2 in complex with Gαq revealed a non-canonical interaction that could be due to interfacial differences imposed by RGS2, the Gα subunit, or both. To resolve this ambiguity, the 2.6 Å crystal structure of RGS8, an R4 subfamily member, was determined in complex with Gαq. RGS8 adopts the same pose on Gαq as it does when bound to Gαi3, indicating that the non-canonical interaction of RGS2 with Gαq is due to unique features of RGS2. Based on the RGS8-Gαq structure, residues in RGS8 that contact a unique α-helical domain loop of Gαq were converted to those typically found in R12 subfamily members, and the reverse substitutions were introduced into RGS10, an R12 subfamily member. Although these substitutions perturbed their ability to stimulate GTP hydrolysis, they did not reverse selectivity. Instead, selectivity for Gαq seems more likely determined by whether strong contacts can be maintained between α6 of the RGS domain and Switch III of Gαq, regions of high sequence and conformational diversity in both protein families.

Synovial sarcoma presenting as an avascular mass: radiologic-pathologic correlation.

Synovial sarcoma is a well-recognized soft tissue malignancy that typically arises in young adults. It is now generally accepted that its origin is likely from undifferentiated mesenchymal tissue with variable epithelial differentiation and a highly specific chromosomal translocation in more than 95% of cases. The lesion typically presents as a slow-growing soft tissue mass, with MR imaging demonstrating a heterogeneous mass with variable amounts of low-, intermediate- and high-signal intensity on fluid-sensitive images and prominent heterogeneous enhancement, reflecting its vascularity. The relative hypervascularity of synovial sarcoma has been well established and is reflected in its enhancement on MR imaging studies. Contrast enhancement on MR imaging has been long used as a marker for tissue vascularization and perfusion, with malignant lesions generally being more vascular and enhancing more rapidly. We recently encountered a patient with a high-grade synovial sarcoma with no discernable necrosis and no vascularity on contrast-enhanced MR images with the subtraction technique, despite enhancement in adjacent regional metastatic lymph nodes. The pathologic basis for this unusual imaging appearance was a paucity of small-caliber vessels within the sarcoma due to extensive hyalinization of the mass.

Strike a pose: Gαq complexes at the membrane.

The heterotrimeric G protein Gαq is a central player in signal transduction, relaying signals from activated G-protein-coupled receptors (GPCRs) to effectors and other proteins to elicit changes in intracellular Ca(2+), the actin cytoskeleton, and gene transcription. Gαq functions at the intracellular surface of the plasma membrane, as do its best-characterized targets, phospholipase C-ß, p63RhoGEF, and GPCR kinase 2 (GRK2). Recent insights into the structure and function of these signaling complexes reveal several recurring themes, including complex multivalent interactions between Gαq, its protein target, and the membrane, that are likely essential for allosteric control and maximum efficiency in signal transduction. Thus, the plasma membrane is not only a source of substrates but also a key player in the scaffolding of Gαq-dependent signaling pathways.

Ethnic differences in F cell levels in Jamaica: a potential tool for identifying new genetic loci controlling fetal haemoglobin.

High levels of fetal haemoglobin (HbF) are protective in beta-haemoglobinopathies. The proportion of erythrocytes containing HbF (F-cells, FC) was measured in healthy adults of African and Caucasian ancestry to assess the feasibility of localizing genes for the FC trait using admixture mapping. Participants were Afro-Caribbean (AC) blood donors and residents of a rural enclave with a history of recent German admixture (Afro-German, AG) recruited in Jamaica, and Caucasian Europeans recruited in Jamaica and the UK. FC levels were significantly different between groups (P < 0.001); the geometric mean FC level in the AC sample (n = 176) was 3.75% [95% confidence interval (CI) 3.36-4.18], AG sample (n = 631) was 2.77% (95% CI 2.63-2.92), and among Caucasians (n = 1099) was 3.26% (95% CI 3.13-3.39). After adjustment for age, sex, haemoglobin electrophoresis pattern, and HBG2 genotype, FC levels in the AC group remained significantly different (P < 0.001) from those in the Caucasian and the AG group but the difference between the Caucasian and AG groups became non-significant (P = 0.46) despite substantial differences in average ancestry. The data confirm ethnic differences in FC levels and indicate the potential usefulness of these populations for admixture mapping of genes for FC levels.

Genetic variation on chromosome 6 influences F cell levels in healthy individuals of African descent and HbF levels in sickle cell patients.

Fetal haemoglobin (HbF) is a major ameliorating factor in sickle cell disease. We investigated if a quantitative trait locus on chromosome 6q23 was significantly associated with HbF and F cell levels in individuals of African descent. Single nucleotide polymorphisms (SNPs) in a 24-kb intergenic region, 33-kb upstream of the HBS1L gene and 80-kb upstream of the MYB gene, were typed in 177 healthy Afro-Caribbean subjects (AC) of approximately 7% European admixture, 631 healthy Afro-Germans (AG, a group of African and German descendents located in rural Jamaica with about 20% European admixture), 87 West African and Afro-Caribbean individuals with sickle cell anaemia (HbSS), as well as 75 Northern Europeans, which served as a contrasting population. Association with a tag SNP for the locus was detected in all four groups (AC, P = 0.005, AG, P = 0.002, HbSS patients, P = 0.019, Europeans, P = 1.5 x 10(-7)). The association signal varied across the interval in the African-descended groups, while it is more uniform in Europeans. The 6q QTL for HbF traits is present in populations of African origin and is also acting in sickle cell anaemia patients. We have started to distinguish effects originating from European and African ancestral populations in our admixed study populations.

Efficacy of different Lysigin formulations in the prevention of Staphylococcus aureus intramammary infection in dairy heifers.

The objective was to compare the efficacy of two experimental Staphylococcus aureus mastitis bacterins and a currently marketed five-isolate-based Staph. aureus bacterin (Lysigin, Boehringer Ingelheim Vetmedica, Inc.) with unvaccinated controls. Forty-seven Holstein-Friesian heifers were randomly assigned to one of four groups such that Group 1 (n=11) received a three-isolate experimental bacterin, Group 2 (n=11) received a five-isolate experimental bacterin, Group 3 (n=14) received Lysigin, and Group 4 (n=11) served as unvaccinated controls. Vaccinations were administered twice 28 d apart in late gestation. All groups were challenged with a heterologous strain of Staph. aureus (ATCC 29740) on days 6, 7, and 8 of lactation. Mastitis score, somatic cell count (SCC), milk culture yield, and total daily milk yield data were collected before and after challenge. All 47 cattle developed a Staph. aureus IMI post-challenge with three animals in Group 1 and one animal in Group 3 clearing their Staph. aureus IMI by the end of the study. However, there was no evidence of a difference between vaccinates and control with regard to Staph. aureus clearance rates post-challenge (P> or =0.214). Cattle vaccinated with Lysigin had a lower mean duration of clinical mastitis and lower total mastitis score post-challenge than controls (P=0.045 and P=0.046, respectively). Overall, there was no evidence that any of the vaccinated groups had a lower mean SCC than control (P> or =0.148) for the tested study days. Likewise there was no evidence that vaccinates had greater milk yield than controls post-challenge (P=0.617). Hence, there was no evidence that the vaccines reliably prevented Staph. aureus IMI, but Lysigin showed benefit in reducing the clinical severity and duration of clinical disease post-challenge. Neither of the experimental bacterins appeared to perform better than Lysigin.