Identification of somatic JAK1 mutations in patients with acute myeloid leukemia

Somatic mutations in JAK2 are frequently found in myeloproliferative diseases, and gain-of-function JAK3 alleles have been identified in M7 acute myeloid leukemia (AML), but a role for JAK1 in AML has not been described. We screened the entire coding region of JAK1 by total exonic resequencing of bone marrow DNA samples from 94 patients with de novo AML. We identified 2 novel somatic mutations in highly conserved residues of the JAK1 gene (T478S, V623A), in 2 separate patients and confirmed these by resequencing germ line DNA samples from the same patients. Overexpression of mutant JAK1 did not transform primary murine cells in standard assays, but compared with wild-type JAK1, JAK1^T478S, and JAK1^V623A expression was associated with increased STAT1 activation in response to type I interferon and activation of multiple downstream signaling pathways. This is the first report to demonstrate somatic JAK1 mutations in AML and suggests that JAK1 mutations may function as disease-modifying mutations in AML pathogenesis.     

Renal Hemodynamics in AKI: In Search of New Treatment Targets

Novel therapeutic interventions are required to prevent or treat AKI. To expedite progress in this regard, a consensus conference held by the Acute Dialysis Quality Initiative was convened in April of 2014 to develop recommendations for research priorities and future directions. Here, we highlight the concepts related to renal hemodynamics in AKI that are likely to reveal new treatment targets on investigation. Overall, we must better understand the interactions between systemic, total renal, and glomerular hemodynamics, including the role of tubuloglomerular feedback. Furthermore, the net consequences of therapeutic maneuvers aimed at restoring glomerular filtration need to be examined in relation to the nature, magnitude, and duration of the insult. Additionally, microvascular blood flow heterogeneity in AKI is now recognized as a common occurrence; timely interventions to preserve the renal microcirculatory flow may interrupt the downward spiral of injury toward progressive kidney failure and should, therefore, be investigated. Finally, development of techniques that permit an integrative physiologic approach, including direct visualization of renal microvasculature and measurement of oxygen kinetics and mitochondrial function in intact tissue in all nephron segments, may provide new insights into how the kidney responds to various injurious stimuli and allow evaluation of new therapeutic strategies.     

A multi-institutional analysis of clinical outcomes and patterns of care of 1p/19q codeleted oligodendrogliomas treated with adjuvant or salvage radiation therapy

Journal of Neuro-Oncology - Practice patterns vary for adjuvant treatment of 1p/19q-codeleted oligodendroglioma patients. This study evaluates the outcomes of adjuvant (aRT) versus salvage...     

Dialytic care of patients with acute renal failure

Acute renal failure remains a common and life-threatening disease with a very high mortality. Renal replacement therapy only provides supportive care. The purpose of this review is to discuss the indications and complications of renal replacement therapies in acute renal failure. Various controversial issues such as biocompatibility of membranes, adequacy of dialysis and utilization of continuous renal replacement therapies in acute renal failure are also covered. The nutritional needs of a patient with acute renal failure receiving renal replacement therapy are also explained. Finally, the outcome of patients with acute renal failure requiring dialysis is discussed.     

Intravital imaging of the kidney using multiparameter multiphoton microscopy

Intravital optical microscopy provides a powerful means of studying the cell biology in the most physiologically relevant setting. The ability of multiphoton microscopy to collect optical sections deep into biological tissues has opened up the field of intravital microscopy to high-resolution studies of multiple organs. Presented here are examples of how two-photon microscopy can be applied to intravital studies of kidney physiology and the study of disease processes. These include studies of cell vitality and apoptosis, fluid transport, receptor-mediated endocytosis, blood flow, and leukocyte trafficking. Efficient two-photon excitation of multiple fluorophores permits comparison of multiple probes and simultaneous characterization of multiple parameters. Two-photon microscopy can now provide a level of investigation previously unattainable in intravital microscopy, enabling kinetic analyses and physiological studies of the organs of living animals with subcellular resolution. Therefore, application of this technology will provide direct visualization of organ-specific and cell-specific responses to an array of stimuli and therapeutic approaches, enhancing our understanding and treatment of disease processes.     

In vitro activities of MK-826 (L-749,345) against 363 strains of anaerobic bacteria

The activity of MK-826 was compared to the activities of cefoxitin, ceftriaxone, imipenem, and meropenem against 363 gram-negative and gram-positive anaerobes by using NCCLS procedures. At least 98% of the strains were susceptible to the carbapenems. All strains of Clostridium perfringens, Fusobacterium nucleatum, Peptostreptococcus, and Sutterella wadsworthensis were susceptible to all agents tested.     

Acute renal failure

Acute renal failure remains an important clinical problem with little progress made in the therapeutic approach over the past 20-30 years. The purpose of this review is to discuss possible etiologies, their diagnosis, differentiation and possible prevention. The pathophysiology of prerenal azotemia and ischemic acute renal failure are also discussed. The importance of understanding different body volume components, the urine analysis and the FE Na(+) are explained.     

Erythropoietin requirements increase following hospitalization in end-stage renal disease patients.

The effect of hospitalization on an ESRD patient's hemoglobin (Hgb) level and erythropoietin (Epo) requirement has not been investigated. We postulated patients with end stage renal disease required an increased Epo dose to maintain stable Hgb during hospitalization and for a period following discharge. To evaluate this hypothesis, we conducted a retrospective chart review on 65 hemodialysis patients. All hemodialysis patients admitted for more than 2 days who did not have more than the index hospitalizations for 2 months prior to and following discharge were included. Multiple parameters including Hgb, Epo dose, intravenous iron dose, serum iron, TIBC, and ferritin during the 2 months before and the two months after hospitalization, Hgb at admission and discharge, Hgb trough, surgery, blood transfusions and co-morbid factors were evaluated. Statistical significance was evaluated using ANOVA or rank-sum testing, as appropriate. In 65 hemodialysis patients (24 M/41 F, age 58 +/- 2.2 years, mean +/- SEM), Hgb levels following discharge and for 2 subsequent months were significantly lower than 2 months prior to admission (11.4 +/- 0.25 vs. 10.7 +/- 0.22 g/dl, p < 0.01). This occurred in spite of an increase in Epo dose (128 +/- 14 vs. 185 +/- 21 U/kg/week, p < 0.0001) over this 2-month period. There was no difference in the iron saturation before and after hospitalization (22 vs. 23%,p > 0.05). There were also no apparent effects of comorbid factors, including surgery, or discharge diagnosis on the changes in Hgb or Epo requirements. However, patients who required a blood transfusion during the hospitalization had lower Hgb levels and higher Epo doses both prior to and after hospitalization, as well as lower Hgb trough levels. In addition, females had lower Hgb levels than males both prior to and after hospitalization, and were receiving a higher Epo dose 191 +/- 18 vs. 129 +/- 20 U/kg/week at 1 month and 215 +/- 18 U/kg/week vs. 134 +/- 22, p < 0.005 at 2 months after hospitalization. CONCLUSION: This study points out that hemodialysis patients experience a significant and prolonged decrease in Hgb levels after hospitalization, even despite a moderate increase in Epo dosing.     

Concentration of Myo-inositol in Skeletal Muscle of the Rat Occurs without Active Transport

The cellular uptake of nonphosphorylated myo-inositol (MI) and its incorporation into phosphoinositide in the rat epitrochlearis muscle was measured. Cellular uptake of [2-³H]MI was determined by the difference between total uptake and [2-³H]MI present in the extracellular fluid determined with [1-¹⁴C]mannitol. Cellular uptake was parabolic and directly proportional to medium MI concentrations between 25 and 3,200 μM. Saturation of a MI carrier was not evident. Moreover, uptake was not inhibited by 2 mM ouabain, 0.3 mM 2,4-dinitrophenol, or 22 mM glucose. Insulin, 100 mU/ml, was without effect on either cellular uptake of [2-³H]MI or its incorporation into phosphoinositides. In muscles that were preloaded with [2-³H]MI and then incubated in media that contained a constant amount of MI but no [2-³H]MI, 44.3% of the [2-³H]MI was released after 10 min increasing to 62.5% by 120 min. Cellular MI concentrations were 0.18 μmol/g wet tissue (four times plasma levels) in rapidly isolated and frozen epitrochlearis muscle. When muscle was incubated without MI, 48% of endogenous MI was lost rapidly. Restoration of cellular MI in 50 μM MI media occurred in two phases, a rapid uptake phase lasting 10 min and a subsequent slow phase of MI uptake.