Publications by authors named "Duner E"

Viral triggers at the intestinal mucosa can have multiple global effects on intestinal integrity, causing elevated intestinal barrier strength and relative protection from subsequent inflammatory bowel disease (IBD) induction in various models. As viruses can interfere with the intestinal immune system both directly and indirectly through commensal bacteria, cause-effect relationships are difficult to define. Due to the complexity of putatively causative factors, our understanding of such virus-mediated protection is currently very limited.

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Background: The primary aim of our study was to determine provider variation in diagnostic yield in a pediatric endoscopy center. Secondary aims were to examine ileal intubation rates as well as procedural complications at the provider level.

Methods: A retrospective review of sequential pediatric patients who underwent a colonoscopy, completed by June 2018, determined the rates of endoscopically abnormal (EA) and isolated histologically abnormal (IHA) colonoscopies; the overall diagnostic yield was the combination of EA and IHA.

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The most common causes of morbidity and mortality in myeloproliferative neoplasms (MPN) are thrombotic and hemorrhagic complications. The JAK2V617F mutation, commonly found in MPN, correlates with several clinical and laboratory characteristics even if the relevance of JAK2V617F allele burden in the natural history of these diseases is unclear. In this study we searched, a relation between thrombotic and hemorrhagic complications and JAK2V617F allele burden level in MPN patients.

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Background: Though the presence of platelets-derived microparticles (MPs) have previously been described in heparin-induced thrombocytopenia (HIT), the mechanism of thrombosis in HIT remains poorly understood. We aimed to assess the presence and origin of MPs in patients with HIT and their possible contribution to HIT with thrombosis (HITT).

Methods: Forty-five patients with HIT and 45 matched hospitalized patients with not confirmed HIT (HIT-negative) were enrolled.

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Sporadic essential thrombocythaemia (ET) is rare in paediatrics, and the diagnostic and clinical approach to paediatric cases cannot be simply copied from experience with adults. Here, we assessed 89 children with a clinical diagnosis of ET and found that 23 patients (25·8%) had a clonal disease. The JAK2 V617F mutation was identified in 14 children, 1 child had the MPL W515L mutation, and 6 had CALR mutations.

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Essential thrombocythemia (ET) is extremely rare in the pediatric population. In most patients no molecular abnormality can be found, with about 40% of pediatric patients harboring a JAK2 V617F mutation. Another recurrent mutation, involving a W to L or K transversion at MPL codon 515, has been reported in about 3-8% of adult ET patients.

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Background: JAK2V617F mutation occurs in 90% of polycythemia vera (PV) and in 50% of essential thrombocythemia (ET) patients.

Materials And Methods: 253 consecutive patients affected by myeloproliferative disorders (MPD, 121 PV, 132 ET) were evaluated and stratified in 4 age groups: 18-39, 40-59, 60-75 and over 75 years (>75). The JAK2V617F mutation was searched and its allele burden was evaluated.

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Article Synopsis
  • Philadelphia-negative myeloproliferative disorders (Ph-MPD) can lead to unusual vein thrombosis, commonly treated with heparin, which poses a risk for heparin-induced thrombocytopenia (HIT).
  • A study reviewed 29 patients with Ph-MPD who were treated with heparin, finding that 17% developed new thrombotic events like pulmonary embolism, with 6.8% diagnosed with HIT.
  • The results emphasize the need for careful monitoring of platelet counts in Ph-MPD patients undergoing heparin therapy, as new thrombosis may indicate HIT.
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More than 20 DNA mutations with different inheritance pattern have been described in patients with Bernard-Soulier Syndrome (BSS), leading to abnormal or absent synthesis and/or expression of GPIbalpha. Clinical phenotype shows considerable variation between individuals, such as bleeding, platelet count and the percentage of large platelets. We describe in a BSS patient the first case of homozygous four bases deletion (TGAG) in the gpIbalpha gene coding sequence, leading to a premature stop codon.

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Amiodarone (AMI) is a potent antiarrhythmic agent; however, its clinical use is limited due to numerous side effects. In order to investigate the structure--cytotoxicity relationship, AMI analogues were synthesized, and then, using rabbit alveolar macrophages, were tested for viability and for the ability to interfere with the degradation of surfactant protein A (SP-A) and with the accumulation of an acidotropic dye. Our data revealed that modification of the diethylamino-beta-ethoxy group of the AMI molecule may affect viability, the ability to degrade SP-A and vacuolation differently.

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Article Synopsis
  • Surfactant-associated protein B (SP-B) is essential for pulmonary surfactant function, but human synthesis and kinetics were previously unknown.
  • Researchers infused newborn infants with a specific carbon isotope to track SP-B synthesis and measured its levels alongside surfactant components using advanced chromatography.
  • The study found that SP-B had a fractional synthesis rate of 30% per day, with a half-life of 21 hours, indicating it may be produced and cleared more rapidly than other surfactant components, aligning with animal studies.
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Amiodarone, an antiarrhythmic drug toxic toward the lung, is metabolized through sequential modifications of the diethylaminoethoxy group to mono-N-desethylamiodarone (MDEA), di-N-desethylamiodarone (DDEA), and amiodarone-EtOH (B2-O-EtOH), whose effects on lung cells are unclear. To clarify this, we exposed rabbit alveolar macrophages to analogs with different modifications of the diethylaminoethoxy group and then searched for biochemical signs of cell damage, formation of vacuoles and inclusion bodies, and interference with the degradation of surfactant protein A, used as a tracer of the endocytic pathway. The substances studied included MDEA, DDEA, and B2-O-EtOH, analogs with different modifications of the diethylaminoethoxy group, fragments of the amiodarone molecule, and the antiarrhythmic agents dronedarone (SR-33589) and KB-130015.

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Background & Aims: The biliary epithelium is involved both in bile production and in the inflammatory/reparative response to liver damage. Recent data indicate that inflammatory aggression to intrahepatic bile ducts results in chronic progressive cholestasis.

Methods: To understand the effects of nitric oxide on cholangiocyte secretion and biliary tract pathophysiology we have investigated: (1) the effects of proinflammatory cytokines on NO production and expression of the inducible nitric oxide synthase (NOS2), (2) the effects of NO on cAMP-dependent secretory mechanisms, and (3) the immunohistochemical expression of NOS2 in a number of human chronic liver diseases.

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Primary biliary cirrhosis (PBC) is a disorder of unknown origin with autoimmune features. Recently, impaired biliary secretion of bicarbonate has been shown in patients with PBC. Here we have investigated whether bile duct epithelial cells isolated from PBC patients exhibit defects in transepithelial bicarbonate transport by analyzing the activities of 2 ion exchangers, Cl(-)/HCO3(-) anion exchanger 2 (AE2) and Na(+)/H(+) exchanger (NHE) in isolated cholangiocytes.

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Background And Aims: Cholestatic disorders often are associated with portal inflammation, but whether or how inflammation contributes to cholestasis is unknown. Thus we studied the effects of proinflammatory cytokines on bile duct epithelia secretory mechanisms.

Methods: Isolated bile duct units (IBDUs) were cultured with interleukin (IL)-6, interferon gamma, tumor necrosis factor (TNF)-alpha, and IL-1 alone or in combination.

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As arterial hypertension is frequently associated with diabetes, it is possible that altered intracellular free calcium ([Ca2+]i) handling, as reported in non-insulin-dependent diabetic patients, is accounted for by abnormalities caused by hypertension rather than diabetes. Our aim was to investigate [Ca2+]i transients triggered by two extracellular agonists, bradykinin and angiotensin II, with or without chronic insulin exposure, in cultured skin fibroblasts from 10 normotensive and 10 hypertensive non-insulin-dependent patients, matched for age, body mass index, and metabolic control, with fibroblasts from 10 healthy control subjects. Long-term cultured fibroblasts were loaded with fura 2-AM for measurement of [Ca2+]i.

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1. Whether an alteration in cell membrane cation transport after exposure to insulin and angiotensin II (two important growth promoters that have been shown to be involved in the pathogenesis of atherosclerosis and hypertension) is present in cells from non-insulin-dependent diabetes patients with microalbuminuria, a known risk factor for cardiovascular and renal disease, is unknown. We therefore examined intracellular pH and calcium changes after acute exposure to insulin and angiotensin II in cultured skin fibroblasts from eight non-insulin-dependent diabetes patients with and eight others without microalbuminuria and from a group of seven matched, normal control subjects.

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An increased activity of Na+/H+ antiport has been reported in leukocytes and fibroblasts from insulin-dependent diabetic (IDDM) patients with nephropathy. To test whether a similar abnormality is present in fibroblasts from non-insulin-dependent diabetic (NIDDM) patients with microalbuminuria and hypertension, we examined intracellular pHi and Na+/H+ antiport activity, using the pH sensitive dye 2', 7'-bis (2-carboxyethyl-5(6)-carboxyfluorescein (BCECF), in cultured skin fibroblasts obtained from 34 NIDDM patients, divided into four groups based upon whether they had microalbuminuria or hypertension, or both: Group 1, nine NIDDM patients with microalbuminuria and hypertension. Group 2, nine NIDDM patients with hypertension and normal albumin excretion rate.

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We assessed the metabolism of the two KBs, AcAc and 3-BOH; the relationships between ketogenesis and FFA inflow rate; and the effect of chronic sulfonylurea treatment in mild NIDDM patients (plasma glucose less than 10 mM). We studied 10 nonobese NIDDM patients in a crossover, randomized, double-blind, placebo-controlled fashion. Each patient was studied 4 times: after a run-in period with placebo, after 3 mo of placebo treatment, after 3 mo of glibenclamide treatments, respectively, and after 3 mo of sulfonylurea treatment during an acute exogenous Intralipid infusion.

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In insulin deficiency, there is excessive arterial delivery of free fatty acid (FFA) to muscles where they are converted to acetoacetyl-CoA and acetyl-CoA. These intermediates may be metabolized further to acetoacetate and beta-hydroxybutyrate, which can be released into the venous circulation. When ketone body (KB) tracers are infused in vivo, they are diluted across muscle tissue.

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This study was performed to verify: (1) the ability of different insulin concentrations to restrict the lipolytic and ketogenic responses to exogenous epinephrine administration; (2) whether the ability of insulin to suppress the lipolytic and ketogenic responses during epinephrine administration is impaired in Type 1 (insulin-dependent) diabetic patients. Each subject was infused on separate occasions with insulin at rates of 0.2, 0.

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To evaluate the anabolic effects of hyperinsulinemia and hyperaminoacidemia on amino acid (and protein) metabolism in type 1 (insulin-dependent) diabetes mellitus (IDDM), we studied leucine and phenylalanine kinetics in nine IDDM and seven control subjects, both at basal euglycemic conditions and during a euglycemic hyperinsulinemic clamp (approximately 60-80 microU/ml of plasma free insulin), combined with an intravenous infusion of amino acids (AA), which doubled plasma concentrations of most AA. In the basal state, euglycemia was maintained in IDDM subjects at the expense of a peripheral free insulin level (16 +/- 2 microU/ml) greater (P less than 0.05) than controls (9 +/- 1 microU/ml).

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The pathogenesis of diabetic nephropathy remains elusive. A role for renal prostaglandins in antagonizing the hormonal effects of renin-angiotensin II has been postulated as a putative factor leading to hyperfiltration in patients with Type 1 (insulin-dependent) diabetes mellitus. Our aim was to elucidate the effects of angiotensin II on kidney haemodynamics and on blood pressure in eight normal subjects, in nine normotensive, in nine hypertensive with normal sodium-lithium countertransport activity in erythrocytes, in seven hypertensive without and in eight hypertensive Type 1 diabetic patients with microalbuminuria and with high sodium-lithium countertransport activity in erythrocytes.

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