Evidence for Association of Non-acetylated Histones with Newly Replicated Epstein-Barr Virus DNA

Epstein-Barr Virus (EBV) has two states of infection, latent and lytic. During the latent state the viral genome remains stable in cells as episomes and replicates with cellular DNA. During the lytic cycle the viral DNA becomes amplified and packaged in newly formed virions. An unsolved problem is whether newly replicated EBV DNA produced upon lytic cycle activation is associated with histones, and if so, whether these histones are acetylated. This question has biological significance as knowing the chromatin structure of genes is important in determining their function and expression profile. Our hypothesis is that newly synthesized EBV lytic DNA is associated with histones and the histone tails are selectively acetylated. To investigate our hypothesis we performed chromatin immunoprecipitation (ChIP) in HH514-16 cells, a Burkitts Lymphoma cell line, during latent and lytic replication. We used quantitative PCR (qPCR) to detect the relative concentration of DNA among the different samples. We tested three different variables: type of inducing agent, duration of treatment, and different regulatory regions in the genome of Epstein-Barr Virus. We found that in cells induced into the lytic cycle with Trichostatin A (TSA), a histone deacetylase inhibitor (HDACi), association of newly replicated EBV DNA with acetylated histone 3 (H3) increased ~ 6-10 fold. This increase in association was greatest 72 hrs after treatment. Furthermore, activation of lytic viral replication in HH514-16 cells using a different inducing agent, Azacytidine (AZC), which is known to function as a DNA methyltransferase inhibitor, increased binding of H3 with viral DNA ~8 fold. However, unlike TSA, AZC increased the acetylation state of histones bound to newly synthesized viral DNA only ~ 2 fold. Changing the regulatory region of the EBV genome analyzed in qPCR did not affect our results. Our results suggest that newly replicated viral DNA is associated with histones, a fraction of which are acetylated. The degree of acetylation likely depends on the agent used to induce the lytic cycle. H3 is highly acetylated when an HDACi is used and less acetylated when AZC is used. Our study provides new insight on the epigenetic profile of newly replicated viral DNA during the lytic cycle. It remains to be determined whether histones are packaged together with viral genomes into virions and whether the chromatin state of virion DNA affects gene expression after the virus enters uninfected cells

Unexpected Widespread Hypophosphatemia and Bone Disease Associated with Elemental Formula Use in Infants and Children

OBJECTIVE: Hypophosphatemia occurs with inadequate dietary intake, malabsorption, increased renal excretion, or shifts between intracellular and extracellular compartments. We noticed the common finding of amino-acid based elemental formula [EF] use in an unexpected number of cases of idiopathic hypophosphatemia occurring in infants and children evaluated for skeletal disease. We aimed to fully characterize the clinical profiles in these cases. METHODS: A retrospective chart review of children with unexplained hypophosphatemia was performed as cases accumulated from various centres in North America and Ireland. Data were analyzed to explore any relationships between feeding and biochemical or clinical features, effects of treatment, and to identify a potential mechanism. RESULTS: Fifty-one children were identified at 17 institutions with EF-associated hypophosphatemia. Most children had complex illnesses and had been solely fed Neocate® formula products for variable periods of time prior to presentation. Feeding methods varied. Hypophosphatemia was detected during evaluation of fractures or rickets. Increased alkaline phosphatase activity and appropriate renal conservation of phosphate were documented in nearly all cases. Skeletal radiographs demonstrated fractures, undermineralization, or rickets in 94% of the cases. Although the skeletal disease had often been attributed to underlying disease, most all improved with addition of supplemental phosphate or change to a different formula product. CONCLUSION: The observed biochemical profiles indicated a deficient dietary supply or severe malabsorption of phosphate, despite adequate formula composition. When transition to an alternate formula was possible, biochemical status improved shortly after introduction to the alternate formula, with eventual improvement of skeletal abnormalities. These observations strongly implicate that bioavailability of formula phosphorus may be impaired in certain clinical settings. The widespread nature of the findings lead us to strongly recommend careful monitoring of mineral metabolism in children fed EF. Transition to alternative formula use or implementation of phosphate supplementation should be performed cautiously with as severe hypocalcemia may develop

Long-Term Follow-up of Hypophosphatemic Bone Disease Associated With Elemental Formula Use: Sustained Correction of Bone Disease After Formula Change or Phosphate Supplementation

In this article, we describe the long-term outcomes of children who were previously reported to have developed hypophosphatemic bone disease in association with elemental formula use. An extended chart review allowed for an updated report of 34 children with regard to severity/duration of bone disease, extent of recovery, and time to correction using radiology reports and biochemical data. After implementation of formula change and/or phosphate supplementation, we found that serum phosphorus concentration increased and serum alkaline phosphatase activity decreased in all patients, normalizing by 6.6 ± 4.0 (mean ± SD) months following diagnosis. The decrease in serum alkaline phosphatase from diagnosis to the time of correction was moderately correlated with the concurrent increase in serum phosphorus (R = 0.48, P < .05). Age at diagnosis significantly correlated with time to resolution (R = 0.51, P = .01). This study supports the earlier report that bone disease associated with hypophosphatemia during elemental formula use responds to formula change and/or phosphate supplementation

The Incidence of Erosive Esophagitis as a Complication of Pediatric Diabetic Ketoacidosis

Introduction. Gastrointestinal (GI) symptoms commonly occur during diabetic ketoacidosis (DKA) and typically resolve with treatment. However, GI complications can persist after DKA resolves. The incidence of upper GI bleeding during DKA in adults has been described, with erosive esophagitis one of the most common lesions. The incidence of GI bleeding or erosive esophagitis in children with DKA has not been previously reported. We performed a retrospective chart review of DKA admissions in children 0 to <18 years with type 1 diabetes mellitus (T1DM) at a pediatric hospital between January 2009 and July 2016. Among 395 episodes of DKA over 7.5 years, erosive esophagitis occurred during two DKA admissions (0.5%) and there were no episodes of GI bleeding. Case presentations. Both episodes of erosive esophagitis occurred in adolescent males with known T1DM who presented with severe DKA. Both developed odynophagia after resolution of DKA and were readmitted for DKA recurrence. Upper endoscopy for both patients showed erosive esophagitis. Biopsies were negative for infection, though candida was found during one patient’s endoscopy. Both had resolution of their esophagitis symptoms with medication management; neither has had recurrence. Conclusion. Erosive esophagitis, a rare complication of pediatric DKA, can manifest with odynophagia or substernal chest pain. This complication can lead to DKA recurrence, likely due to increased insulin resistance from inflammation and pain and from reduced oral intake and insulin administration. Patients with odynophagia associated with DKA should be monitored closely to allow timely evaluation and treatment of esophagitis

Unexpected widespread hypophosphatemia and bone disease associated with elemental formula use in infants and children

Objective Hypophosphatemia occurs with inadequate dietary intake, malabsorption, increased renal excretion, or shifts between intracellular and extracellular compartments. We noticed the common finding of amino-acid based elemental formula [EF] use in an unexpected number of cases of idiopathic hypophosphatemia occurring in infants and children evaluated for skeletal disease. We aimed to fully characterize the clinical profiles in these cases. Methods A retrospective chart review of children with unexplained hypophosphatemia was performed as cases accumulated from various centres in North America and Ireland. Data were analyzed to explore any relationships between feeding and biochemical or clinical features, effects of treatment, and to identify a potential mechanism. Results Fifty-one children were identified at 17 institutions with EF-associated hypophosphatemia. Most children had complex illnesses and had been solely fed Neocate® formula products for variable periods of time prior to presentation. Feeding methods varied. Hypophosphatemia was detected during evaluation of fractures or rickets. Increased alkaline phosphatase activity and appropriate renal conservation of phosphate were documented in nearly all cases. Skeletal radiographs demonstrated fractures, undermineralization, or rickets in 94% of the cases. Although the skeletal disease had often been attributed to underlying disease, most all improved with addition of supplemental phosphate or change to a different formula product. Conclusion The observed biochemical profiles indicated a deficient dietary supply or severe malabsorption of phosphate, despite adequate formula composition. When transition to an alternate formula was possible, biochemical status improved shortly after introduction to the alternate formula, with eventual improvement of skeletal abnormalities. These observations strongly implicate that bioavailability of formula phosphorus may be impaired in certain clinical settings. The widespread nature of the findings lead us to strongly recommend careful monitoring of mineral metabolism in children fed EF. Transition to alternative formula use or implementation of phosphate supplementation should be performed cautiously with as severe hypocalcemia may develop