Publications by authors named "Michael E Ullian"

Background: Peritoneal dialysis (PD) is a commonly used form of renal replacement therapy for patients that have reached end-stage renal disease. Acute bacterial peritonitis (ABP) in chronic PD patients results in pain, increased costs, injury to the peritoneal membrane, and PD modality failure. Optimal antibiotic treatment of acute bacterial peritonitis (ABP) in chronic PD patients should be intraperitoneal, outpatient-based, appropriate, prompt, and uninterrupted.

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Article Synopsis
  • Chronic peritoneal dialysis (PD) patients commonly experience low potassium levels (hypokalemia), but hyperkalemia (high potassium levels) is also a concern, occurring in 14% of serum samples from a study of 33 patients over varying durations of PD.
  • The study found that hyperkalemia was mostly mild, yet some cases were extreme, and its occurrence did not significantly change over the years on PD.
  • Factors leading to hyperkalemia in PD patients could include dietary intake of potassium, noncompliance with dialysis, increased muscle mass, shifts in potassium levels, and periods without dialysis.
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Background: Chronic in-center hemodialysis (HD) patients may experience more morbidity and mortality after the weekend. Since our Veterans Administration Hospital HD unit is closed on the weekend, non-traditional HD schedules were created. Some schedules contained a 4-day weekend compared to the usual 3-day weekend.

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Background: To come into compliance with South Carolina statute, we changed how nurses handle medications (antibiotics, erythropoietin [EPO], calcitriol and heparin) in our outpatient home dialysis clinic. Nurses continued to administer medications in the clinic but no longer dispensed medications for patients to take home; instead, medications were dispensed from pharmacies to the patients by mail. We hypothesized that the abovementioned change in medication handling worsened clinical outcomes.

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The vasoactive hormone angiotensin II initiates its major hemodynamic effects through interaction with AT1 receptors, a member of the class of G protein-coupled receptors. Acting through its AT1R, angiotensin II regulates blood pressure and renal salt and water balance. Recent evidence points to additional pathological influences of activation of AT1R, in particular inflammation, fibrosis and atherosclerosis.

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The major effects of Angiotensin II (AngII) in vascular tissue are mediated by AngII AT1A receptor activation. Certain effects initiated by AT1A receptor activation require receptor internalization. In rat aortic vascular smooth muscle cells (RASMC), AngII stimulates cyclooxygenase 2 protein expression.

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Objective: Since peritoneal dialysis causes peritoneal fibrosis, we examined how glucose (osmotic factor), mannitol (osmotic control), and angiotensin II (AngII) regulate proinflammatory cyclooxygenase 2 (COX-2) in primary rat peritoneal mesothelial cells. Materials and Methods: For this study, we used the following material (n = 4-8 cell lines): cells, passages 1-2; I-AngII receptor surface binding (AT1R antagonist losartan, AT2R antagonist PD123319; both 10 µM); intracellular calcium probe calcium-5; COX-2 immunoblotting (β-actin normalized); real-time PCR of COX-2 gene PTGS2, and NF-κB inhibitor Ro-1069920 (5 µM). Results: AngII surface receptors were predominantly AT1R (minimally AT2R).

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Activation of the angiotensin type 1A receptor (AT1AR) in rat aorta vascular smooth muscle cells (RASMC) results in increased synthesis of the proinflammatory enzyme cyclooxygenase-2 (COX-2). We previously showed that nuclear localization of internalized AT1AR results in activation of transcription of the gene for COX-2, i.e.

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We report the case of acute peritonitis caused by a rapidly growing mycobacterium in a chronic peritoneal dialysis patient, whose renal failure had been caused by diabetic glomerulosclerosis. The organism cultured from the peritoneal dialysis fluid was Mycobacterium wolinskyi. Peritonitis caused by M.

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Background: We tested the hypothesis that patterns of serum creatinine concentrations (S-cr) prior to percutaneous renal biopsy (PRB) predict the utility of PRB in safely making renal diagnoses, revealing treatable disease, and altering therapy in chronic kidney disease patients.

Methods: PRB specimens (170 patients) were assigned to 1 of 5 groups: S-cr never greater than 0.11 mM for at least 6 months prior to PRB (Group 1); S-cr greater than 0.

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Angiotensin II (AngII) initiates cellular effects via its G protein-coupled angiotensin 1 (AT(1)) receptor (AT(1)R). Previously, we showed that AngII-induced expression of the prostanoid-producing enzyme cyclooxygenase 2 (COX-2) was dependent upon nuclear trafficking of activated AT(1)R. In the present study, mastoparan (an activator of G proteins), suramin (an inhibitor of G proteins), 1-[6-[[17beta-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122; a specific inhibitor of phospholipase C), and sarcosine(1)-Ile(4)-Ile(8)-AngII (SII-AngII; a G protein-independent AT(1)R agonist) were used to determine the involvement of G proteins and AT(1A)R trafficking in AngII-stimulated COX-2 protein expression in human embryonic kidney-293 cells stably expressing AT(1A)/green fluorescent protein receptors and cultured vascular smooth muscle cells, respectively.

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Background: We compared the effects of the sulfhydryl-containing (thiol) antioxidant dithiothreitol (DTT), which disrupts disulfide bonds, on cell signaling through angiotensin II (AngII) Type 1 receptors (AT1Rs) and arginine vasopressin (AVP) V1 receptors (V1Rs). The AT1R contains two extracellular disulfides bonds but its ligand contains none, whereas the V1R contains no extracellular disufides bonds but its ligand contains 1.

Methods: We measured radioligand binding, intracellular calcium responses, and extracellular signal-regulated kinase phosphorylation in cultured rat aortic vascular smooth muscle cells and alterations in urine osmolality in intact rats.

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Previously, we demonstrated that nuclear localization of the Angiotensin II AT1A receptor was associated with the activation of transcription for the COX-2 gene, PTGS-2. The hypothesis of the present study is that AT1AR internalization from the plasma membrane is a first step in the nuclear localization of the endogenous AT1AR of rat aortic vascular smooth muscle cells and the resultant increase of COX-2 protein expression. Angiotensin II produced both a time- and concentration-dependent increase in COX-2 protein expression in these cells.

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Angiotensin II (ANG II) type 1 (AT(1)) receptors, similar to other G protein-coupled receptors, undergo desensitization and internalization, and potentially nuclear localization, subsequent to agonist interaction. Evidence suggests that the carboxy-terminal tail may be involved in receptor nuclear localization. In the present study, we examined the carboxy-terminal tail of the receptor for specific regions responsible for the nuclear translocation phenomenon and resultant nuclear activation.

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We describe a patient receiving long-term peritoneal dialysis who experienced 2 episodes of peritonitis in successive months caused by unusual bacteria of environmental origin: Agrobacterium radiobacter, Pseudomonas oryzihabitans, and Corynebacterium aquaticum. A radiobacter and P oryzihabitans occurred simultaneously in the first episode of peritonitis, and C aquaticum, in the second episode. The patient's vocation necessitated exposure to moist soiled conditions.

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Background: Sitosterolemia is a recessively inherited disorder in humans that is associated with premature atherosclerotic disease. Mutations in ABCG5 or ABCG8, comprising the sitosterolemia locus, STSL, are now known to cause this disease. Three in-bred strains of rats, WKY, SHR and SHRSP, are known to be sitosterolemic, hypertensive and they carry a missense 'mutation' in a conserved residue of Abcg5, Gly583Cys.

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Antioxidants seem to inhibit angiotensin II (Ang II) actions by consuming stimulated reactive oxygen species. An alternative hypothesis was investigated: Antioxidants that are also strong reducers of disulfide bonds inhibit the binding of Ang II to its surface receptors with consequent attenuation of signal transduction and cell action. Incubation of cultured vascular smooth muscle cells, which possess Ang II type 1a receptors, with the reducing agent n-acetylcysteine (NAC) for 1 h at 37 degrees C resulted in decreased Ang II radioligand binding in a concentration-dependent pattern.

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