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Biomedical subjects

W Keane

Publications and source records attributed to W Keane.

14 recordsLinked to original sources
PubMed2000

Pathophysiological role of T lymphocytes in renal ischemia-reperfusion injury in mice.

Mononuclear cell infiltrates are found in human renal ischemia-reperfusion injury (IRI), and peritubular T lymphocytes have been identified in experimental IRI. However, the role of T cells in the pathogenesis of renal IRI is unknown. We hypothesized that T cells are one of the important mediators of renal IRI. To test this hypothesis, we used an established mouse model of renal IRI, and evaluated mice with genetically engineered deficiency of both CD4+ and CD8+ T cells. At 48 h postischemia, CD4/CD8-knockout (KO) mice had marked improvement in renal function compared with control C57BL/6 mice (serum creatinine: 0.7 +/- 0.4 vs. 2.5 +/- 0.3 mg/dl, respectively; P < 0.05). Neutrophil infiltration into postischemic kidney was reduced in CD4/CD8 KO mice, compared with control mice, at both 24 h [polymorphonuclear neutrophils (PMNs)/10 high power fields: 714 +/- 354 vs. 3,514 +/- 660, respectively; P < 0.05] and 48 h (88 +/- 32 vs. 1,979 +/- 209, respectively; P < 0.05). Tubular necrosis score in CD4/CD8 KO mice, compared with control mice, was significantly less at 48 h (0.4 +/- 0.1 vs. 2.4 +/- 0.2, respectively; P < 0.05). Because adhesion between T cells and renal tubular epithelial cells (RTECs) may underlie the pathophysiological role of T cells in renal IRI, we also measured T cell adhesion to primary murine RTECs in vitro. Exposure of RTECs to 2 h of hypoxia followed by 1 h of reoxygenation increased T cell adhesion more than twofold. Phorbol ester treatment, which activates integrins, increased T cell adhesion threefold. These data suggest that T lymphocytes can mediate experimental renal IRI. Moreover, adhesion of infiltrating T cells to renal tubular cells may provide a potential mechanism underlying postischemic tubular dysfunction.

Acute Kidney Injury↗
PubMed2000

The future of clinical trials in chronic renal disease: outcome of an NIH/FDA/Physician Specialist Conference. Evaluation of Clinical Trial Endpoints in Chronic Renal Disease Study Group.

For people with chronic renal insufficiency, the therapeutic goal is to prevent progression to end-stage renal disease, a serious condition that can only be treated with dialysis and kidney transplantation. Although restriction of dietary protein slows the progression of renal disease somewhat, the principal treatment to slow chronic renal disease is appropriate reduction of blood pressure. Antihypertensive agents, particularly those that produce sustained, long-term reductions in proteinuria, such as angiotensin-converting enzyme inhibitors, not only decrease blood pressure but also preserve renal function. Clinical trials to evaluate these and other drug therapies in renal disease progression have used both "hard end points" (e.g., dialysis, transplantation, death) and intermediate end points of renal disease progression (e.g., doubling of serum creatinine concentration, reductions in proteinuria). Trials that have used hard end points typically recruited patients with advanced renal disease to demonstrate a difference in therapies within a period of 2 to 5 years. However, proteinuria reduction, along with a decrease in the time to doubling of serum creatinine in very early diabetic renal disease, could demonstrate an altered natural history of renal disease. Although hard end points are indicators of a drug's efficacy in reducing cardiovascular events or preserving renal function, they do not assess the impact of a treatment on altering the natural history of early renal disease. For clinical trials of people with all but the most advanced renal disease, use of intermediate end points of renal disease progression is the only practical option for assessment of treatment efficacy and effectiveness. Given the available data on proteinuria reduction and doubling of serum creatinine from clinical trials, these end points, taken together, appear to provide an acceptable means of assessing a treatment's impact on slowing renal disease progression.

Antihypertensive Agents↗
PubMed1997

Assessment of structure and function in progressive renal disease.

The incidence and prevalence rates of end-stage renal disease (ESRD) in the United States continue to increase. In 1995, the incidence rate was 262 per million population, with a point prevalence rate of 975 per million population. The exact number of individuals with abnormal renal function but not yet at end stage is difficult to assess. Crude estimates suggest that approximately 0.4% of the U.S. population has serum creatinine values greater than 2.0 mg/dl. In some sub-populations, such as African Americans, the estimate is + as high as 1.0%. The rate of progression, likewise, is difficult to assess. In general, renal manifestations of certain systemic diseases such as diabetes mellitus and systemic lupus erythematosus, and those with significant proteinuria (usually greater that 3.0 g/24 hr) seem to have a more rapid progressive course to end stage. If intervention is expected to be successful in halting or slowing down progression, accurate assessment of the early manifestations of renal disease, structure, and function need to be established. Currently accepted methods of assessment of renal disease include measurement of renal function such as serum creatinine and glomerular filtration rate, measurement of proteinuria, assessment of tubular function, glomerular sieving and permselectivity, radiologic imaging techniques, and evaluation of histo-morphometry. Interventions that have been shown to slow progression include control of hypertension, and treatment modalities that reduce proteinuria, such as, the use of angiotensin converting enzyme inhibitors. Further clinical and basic science studies are needed to accurately define the important predictors of progression, and interventions that are effective in slowing or halting progression.

Animals↗
PubMed1992

Single-dose pharmacokinetics of pravastatin and metabolites in patients with renal impairment.

The disposition of a single 20-mg oral dose of pravastatin was assessed in subjects with various degrees of renal function. Sixteen subjects (13 males, 3 females) with creatinine clearance values ranging from 15 to 112 mL/min/1.73 m2 completed the study. Area under the serum concentration-time curve, maximum serum concentration, time to maximum serum concentration, terminal serum elimination half-life, apparent clearance, and apparent volume of distribution for pravastatin were not affected by renal impairment, whereas the renal clearance of pravastatin decreased as creatinine clearance decreased (r2 = 0.697, P less than .001). The area under the serum concentration-time curve and time to maximum serum concentration of SQ 31,945 (a hepatic metabolite) increased in patients with renal impairment, whereas the terminal elimination rate constant and renal clearance of SQ 31,945 significantly decreased as a function of creatinine clearance. The renal clearance of another metabolite (SQ 31,906) also significantly declined with decreasing renal function. This single-dose study demonstrates that pravastatin pharmacokinetics were not affected in patients with renal impairment, probably because of its dual route of elimination.

Administration, Oral↗
PubMed1991

Tracheo-gastric fistula following gastric pull-up.

Tissue damage from gastric acid may be more prevalent than currently believed following gastric pull-up. An intense anti-acid medical regimen should be instituted peri- and postoperatively. In cases where significant peptic ulcer disease exists preoperatively, an alternative means of reconstruction following laryngo-pharyngo-esophagectomy should be considered.

Fistula↗
PubMed1984

Mesangial immune injury, hypertension, and progressive glomerular damage in Dahl rats.

Hypertension frequently accompanies chronic glomerulonephritis. Mesangial injury and glomerulosclerosis are common in glomerulonephritis and are often harbingers of progressive glomerular destruction. Thus, in a model of mesangial immune injury we studied the relationship between hypertension, mesangial injury, and glomerulosclerosis. We induced mesangial ferritin-antiferritin immune complex disease (FIC) in Dahl salt-sensitive (S) and salt-resistant (R) rats. S and R rats with FIC were fed chow containing 0.3% NaCl until 14 weeks of age and then switched to 8.0% NaCl chow until 28 weeks of age. Groups of control S and R rats (no FIC) were either fed 0.3% NaCl for 28 weeks or switched to 8.0% NaCl chow at 14 weeks of age. Blood pressure, serum creatinine, urinary protein, and glomerular injury (assessed by semiquantitative morphometric analysis) were determined at 14 and 28 weeks of age. R rats with or without FIC did not develop hypertension; mesangial injury was minimal. At 14 weeks of age, only S FIC rats developed hypertension, proteinuria, significant mesangial expansion and early glomerulosclerosis. At 28 weeks of age, proteinuria, mesangial expansion, and glomerulosclerosis were significantly more severe in hypertensive S rats with FIC than in those without FIC. These studies show that despite a normal salt intake, mesangial injury hastened the onset of hypertension, but only in rats genetically predisposed to hypertension (S FIC at 14 weeks). High dietary salt further aggravated hypertension, which, in turn, magnified both mesangial injury and glomerulosclerosis. Clinically, the different rates of progression of human glomerulonephritis associated with hypertension may be in part dependent on similar mechanisms.

Animals↗
PubMed1983

Human peritoneal macrophage phagocytic, killing, and chemiluminescent responses to opsonized Listeria monocytogenes.

Opsonization with normal human serum, purified immunoglobulin G, or immunoglobulin G-deficient serum promoted phagocytosis of Listeria monocytogenes by human peritoneal macrophages. However, normal human serum was the most effective opsonin in elicting killing and chemiluminescent responses. Macrophages phagocytized and killed almost as much as polymorphonuclear leukocytes but produced considerably less chemiluminescence.

Ascitic Fluid↗
PubMed1976

Carbenicillin inactivation of aminoglycosides in patients with severe renal failure.

Carbenicillin appears to produce clinically important inactivation of aminoglycoside antibiotics in patients with severe renal failure. If combination carbenicillin/aminoglycoside therapy is used in patients with severe renal failure, the dose of carbenicillin must be adjusted to renal function and serum levels of both drugs should be monitored. Even with therapeutic serum carbenicillin levels (100-200 mug/ml), large doses of aminoglycosides may be required to achieve therapeutic serum levels and this may increase the risk of toxicity.

Aged↗
PubMed1976

C.A.T. scans.

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Humans↗