			Home About us Contact

Tubular Function (tubular + function)

Distribution by Scientific Domains

Medical Sciences	85%
Life Sciences	14%

Kinds of Tubular Function

renal tubular function

Selected Abstracts

Long-term follow-up of renal function after high-dose methotrexate treatment in children

PEDIATRIC BLOOD & CANCER, Issue 4 2008
Marika H. Grönroos MD
Abstract Background High-dose methotrexate (HD-MTX) is commonly used in treatment of pediatric leukemias and lymphomas. Transient deterioration in renal function is frequently noted during HD-MTX treatment, but possible long-term changes are less well known. In this study we aimed to study long-term renal prognosis after HD-MTX treatment, and to find possible underlying risk factors for reduced renal function. Procedure Medical records of pediatric cancer patients treated with HD-MTX were reviewed retrospectively after follow-up of 1,10 years. Renal function before and after chemotherapy was investigated in a total of 28 patients. Assessment of glomerular and tubular function was prospectively evaluated in each case. Glomerular function was evaluated by either 51Cr-EDTA or 99mTc-DTPA clearance methods, and by urinary albumin excretion. Tubular function was assessed by measuring blood electrolyte levels and urinary ,1 - or ,2 -microglobulin. Results A decrease in glomerular filtration rate (GFR) was statistically significant as follow-up time increased (P,=,0.02). Age at the time of diagnosis and exposure to potentially nephrotoxic antibiotics during cancer treatment had no influence on GFR. However, albuminuria was observed more often in patients treated with amphotericin B or gentamycin (P,=,0.04). No changes in tubular function were observed. Conclusions Our results show that HD-MTX treatment significantly decreases GFR and may cause albuminuria in pediatric cancer patients several years after treatment. Long-term renal follow-up of these patients is therefore important. Pediatr Blood Cancer 2008;51:535,539. © 2008 Wiley-Liss, Inc. [source]

Prolonged exposure to inhaled nitric oxide transiently modifies tubular function in healthy piglets and promotes tubular apoptosis

ACTA PHYSIOLOGICA, Issue 4 2009
W. Go, dzik
Abstract Aim:, Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator. We hypothesized that those piglets exposed to prolonged iNO react with a modified renal function. Methods:, Randomized, placebo-controlled exposure to 40 p.p.m. iNO (30 h) in piglets (n = 20). Plasma and urine were sampled during three periods (first and second 12 h periods, and finally a 6 h period). We measured urine volumes, plasma and urine electrolytes (UNa, UK, UCl), plasma creatinine and urea. We calculated creatinine clearance (Ccr), and fractional excretions of sodium and potassium (FENa, FEK) and urinary excretions of electrolytes (UENa, UEK, UECl). Haemodynamic data were recorded and renal tubular apoptosis detected. Results:, For the first 12 h, certain parameters significantly increased in the iNO group (mean ± SD): UNa (mmol L,1), 87.7 (±35.0) vs. 39.3 (±22.9), UCl (mmol L,1) 80.4 (±32.8) vs. 48.0 (±26.7), FENa (%) 2.1 (±0.8) vs. 0.7 (±0.5), FEK (%) 31.7 (±7.0) vs. 20.7 (±12.3), as well as UENa (mmol) 61.0 (±21.1) vs. 27.6 (±17.9) and UECl (mmol) 57.3 (24.5) vs. 37.6 (29.0). These changes were absent in the second and third periods of the study. Significant differences in percentage of apoptotic cell nuclei in the renal cortex and medulla were found after iNO exposure: 39% vs. 15%. Conclusion:, Exposure to 40 p.p.m. iNO in healthy anaesthetized piglets has a transient natriuretic effect that disappears after 12 h. We also found evidence of renal tubular apoptosis promotion after 30 h of iNO. [source]

Time course of the renal functional response to partial nephrectomy: measurements in conscious rats

EXPERIMENTAL PHYSIOLOGY, Issue 1 2007
R. M. Chamberlain
Previous investigations into the functional responses of the surviving nephrons following reductions in renal mass have been performed largely in anaesthetized animals and have taken little account of how the compensatory changes develop with time. The present study has assessed a method for determining glomerular filtration rate (GFR) in unrestrained, uncatheterized, conscious rats (plasma disappearance of 99mTc-diethylenetriamene pentaacetic acid (DTPA)) and has used this method to document the time course of the changes in GFR over a 32 day period following uninephrectomy or 5/6 nephrectomy. Concurrent measurements of excretion rates and of the clearance of lithium (the latter being an index of end-proximal fluid delivery) provided information on changes in overall tubular function and segmental reabsorption. After uninephrectomy, the GFR of the remaining kidney (compared with that of a single kidney of sham-operated animals) increased maximally (by ,50%) within 8 days; after 5/6 nephrectomy, the increase in the GFR of the remnant kidney was maximal (at ,300%) within 16 days. Overall excretion rates of sodium and potassium were well maintained in partially nephrectomized animals throughout the period of study, while the excretion of water increased (by ,30% after uninephrectomy and by ,120% after 5/6 nephrectomy), partly as a result of the compensatory increases in GFR but mainly as a consequence of moderate (after uninephrectomy) or marked (after 5/6 nephrectomy) reductions in fractional reabsorption. During the early period after 5/6 nephrectomy, potassium excretion sometimes exceeded the filtered load, indicating net secretion. Lithium clearance data indicated that the changes in tubular function after 5/6 nephrectomy include a reduction in fractional reabsorption in the proximal tubule, whereas after uninephrectomy any such effect on the proximal tubule is minor and transient. [source]

Clinicopathology of childhood-onset renal systemic lupus erythematosus

NEPHROLOGY, Issue 4 2007
WASIU A OLOWU
SUMMARY: Aims: To determine the clinicolaboratory renal manifestations; glomerular, extra-glomerular histopathologic lesions; renal tubular dysfunction (RTD) frequency and outcome of a short-term renal follow up in Nigerian children with systemic lupus erythematosus (SLE). Methods: A non-randomized prospective study of consecutive cases of childhood-onset SLE with nephropathy was conducted. Baseline/follow-up clinicolaboratory data were collected. Each patient was followed up for 12 months. Results: Seven of the 11 children studied were girls. The median age at diagnosis was 11.0 years. Median diagnosis time interval (1.9 years) and median time of renal disease onset (1.0 year) were similar. Hypertension, nephrotic syndrome and acute renal failure (ARF) occurred in 45.5%, 54.5% and 63.7% of the patients, respectively. The glomerular lesions were non-proliferative lupus nephritis (LN) in 9.0% (class II LN); focal (class III LN) and diffuse (class IV LN) proliferative LN (PLN) in 27.0% and 64.0%, respectively. Tubulointerstitial nephritis (TIN, 91.0%) and RTD (64.0%) were common. ARF (P = 0.033) and RTD (P = 0.015) were significantly associated with severe TIN. Complete renal remission rate at end-point was 71.4%. Relapse and renal survival rates were 14.3% and 86.0%, respectively. RTD was persistent in 43.0%. Conclusion: Renal function disorders, diffuse PLN and extra-glomerular lesions were frequent. Significant association of ARF and RTD with severe TIN in this series suggests the need for early renal tubular function (RTF) assessment in our SLE patients. Deranged RTF may be marker of severe TIN in SLE warranting early confirmatory renal biopsy and aggressive interventional treatment. [source]

Evaluation of renal tubular function in children taking anti-epileptic treatment

NEPHROLOGY, Issue 6 2006
BULENT UNAY
SUMMARY: Aim: To assess the effects of anti-epileptic drugs on renal tubular function. Methods: Urinary N-acetyl-,-D-glucosaminidase activity was measured in 114 epileptic children (mean age 5.6 ± 1.1 years) who were undergoing monotherapy with valproate (n = 46), carbamazepine (n = 34), lamotrigine (n = 13) and combined therapy with valproate+carbamazepine (n = 21). Results: The urinary N-acetyl-,-D-glucosaminidase index of valproate (P < 0.01), carbamazepine (P < 0.05) and polytherapy group (P < 0.01) were significantly elevated when compared with that of the control group. No significant difference in N-acetyl-,-D-glucosaminidase levels was found between the lamotrigine group and the control subjects. We found that the distribution of the N-acetyl-,-D-glucosaminidase values of patients depended significantly on the length of therapy (P < 0.01). The level of urinary excretion of N-acetyl-,-D-glucosaminidase was significantly higher in the patients who were taking long-term treatment (>10 years) with valproate, carbamazepine and combined therapy than those taking therapy shorter than 10 years (P < 0.01). The mean serum concentrations of valproate and carbamazepine were 68.7 ± 17.44 µg/mL and 5.41 ± 1.23 µg/mL, respectively. There was a significant correlation between the serum concentration of valproate and urinary N-acetyl-,-D-glucosaminidase levels (r = 0.44, P < 0.01). There was also a significant correlation between the serum concentration of carbamazepine and N-acetyl-,-D-glucosaminidase excretion (r = 0.52, P < 0.01). Conclusion: The present study demonstrated that in patients treated with valproate and carbamazepine, an impairment of tubular function can be present, whereas lamotrigine does not cause any significant change. [source]

Renal tubular function in children with ,-thalassemia minor

NEPHROLOGY, Issue 5 2005
SÜLEYMAN KALMAN
SUMMARY: Background: , -thalassemia minor is a common heterozygous haemoglobinopathy that is characterized by both microcytosis and hypochromia. It requires no treatment. It has been postulated that low-grade haemolysis, tubular iron deposition and toxins derived from erythrocytes might cause renal tubular damage in adult patients with , -thalassemia minor. Our aim was to investigate the renal tubular functions in children with ,-thalassemia minor and to determine its possible harmful effects. Methods: The study was conducted on 32 children (14 female and 18 male) at the age of 5.8 ± 3.1 years (range 2,14 years) with , -thalassemia minor. The patients were classified as anaemic (haemoglobin (Hb) , 11 g/dL) (Group 1, n = 14) and non-anaemic (Hb > 11 g/dL) (Group 2, n = 18). A control group was formed with 18 healthy children whose ages and sexes match those in other groups (Group 3, n = 18). Fractional excretion of sodium (FENa, %), fractional excretion of magnesium (FEMg, %), fractional excretion of uric acid (FEUA, %) and tubular phosphorus reabsorption (TPR,%) were calculated with standard formulas. Urinary calcium excretion (mg/kg per 24 h), zinc (Zn) (µg/dL), glucosuria (mg/dL), , -2 microglobulin (mg/dL) and N -acetyl- ,,D-glycosaminidase (NAG, U/mmol creatinine) levels were measured through biochemical methods. Results: There was no statistically significant difference among the three groups in terms of the results of FENa (%), FEMg (%), FEUA (%), TPR (%), calciuria (mg/kg per 24 h), NAG, urine Zn, proteinuria, glucosuria or urine , - 2 microglobulin levels (P > 0.05). Conclusion: On the contrary of children with , -thalassemia major, renal tubular dysfunction has not been determined in children with , -thalassemia minor in the present study. [source]

Changes in renal hemodynamics and urodynamics in rats with chronic hyperoxaluria and after acute oxalate infusion: Role of free radicals

NEUROUROLOGY AND URODYNAMICS, Issue 2 2003
Ho-Shiang Huang
Abstract Aims The aim of this study was to evaluate possible changes in renal hemodynamic and urodynamic parameters in rats with chronic hyperoxaluria and after acute oxalate challenge. We also evaluated the possible association between free radical (FR) production, hyperoxaluria, and calcium oxalate (CaOx) calculi formation. Methods Chronic hyperoxaluria was induced by adding 0.75% ethylene glycol (EG) to the drinking water of male Wistar rats. After 7, 21, and 42 days of treatment, urinary biochemistry, oxalate levels, and lipid peroxides were measured. Kidney calculi were examined by polarizing microscopy. In the second part of the experiments, 1, 10, 20, and 30 mg kg,1 hr,1 oxalate was infused, by means of an intrarenal arterial catheter (IRA), into normal rats sequentially. Superoxide dismutase (SOD) infusion by means of IRA, in addition to oxalate, was also performed to check its influence on the altered renal function after oxalate infusion. In both the acute and chronic groups, renal blood flow (RBF), cortical microvascular blood flow (CMVBF), glomerular filtration rate (GFR), urine flow (UV), and urinary sodium excretion (UNaV) were measured, and chemiluminescence (CL) was examined in the renal venous blood. Results Levels of urinary lipid peroxides and enzymuria had increased since day 7, and increased the size of numbers of CaOx crystals in the kidney were noted beginning on day 21, but elevated CL was detectable only on day 7 after 0.75% EG treatment. Decreased UV and UNaV were noted in the 42-day EG group, although the 24-hr creatinine clearance values were normal in all experimental groups. On the other hand, RBF, GFR, and CMVBF were attenuated with elevated FR when the oxalate concentration was higher than 10 mg kg,1 hr,1 in the acute oxalate infusion group. With SOD pretreatment, the decreased RBF, GFR, and CMVBF could be reversed at 10 mg kg,1 hr,1 of oxalate, and be partially reversed at 20. FR also could be reduced significantly at 10 and 20 mg kg,1 hr,1 of oxalate. Conclusions Decreased urine flow and sodium excretion were the main renal functions affected by chronic hyperoxaluria. However, that only the 42-day EG group had a decreased tubular function cannot be fully explained by the persistent tubular enzymuria and increased lipid peroxides that began on day 7 after EG treatment. With acute oxalate infusion, the major insult to renal function was renal hemodynamics. Pretreated SOD could reverse the attenuated hemodynamics and reduce the elevated FR partly, which suggested that FR is responsible for oxalate toxicity. Neurourol. Urodynam. 22:176,182, 2003. © 2003 Wiley-Liss, Inc. [source]

Long-term follow-up of renal function after high-dose methotrexate treatment in children

Effect of perioperative steroids on renal function after liver transplantation,

ANAESTHESIA, Issue 3 2006
S. Turner
Summary Subclinical renal dysfunction is thought to occur as a systemic manifestation of ischaemia-reperfusion injury of other organs. Liver transplantation is associated with major ischaemia-reperfusion injury. Thirty-four patients undergoing elective liver transplantation were randomly allocated to receive either saline or 10 mg.kg,1 methylprednisolone on induction of anaesthesia. Urine was taken for N-acetyl-,-D-glucosaminidase, creatinine and other markers of tubular function. Serum chemistry was measured for 7 days. Creatinine concentration increased in the saline group but not in the methylprednisolone group (p < 0.0001), with the greatest difference on the third postoperative day (mean (SD) 164.8 (135.8) ,mol.l,1vs 88.5 (39.4) ,mol.l,1, respectively). Similar changes were seen in postoperative alanine transferase (865 (739) U.l,1vs 517 (608) U.l,1, respectively; p <,0.0001) on the second postoperative day. Both groups exhibited increases in markers of renal tubular dysfunction and of glomerular permeability. Patients in the saline group sustained more adverse events (8/17 (47%) vs 2/17 (12%); p = 0.02). The data confirm increased proximal tubular lysosomal turnover, consistent with an increased tubular protein load, following liver transplantation, and suggest that methylprednisolone protects against renal and hepatic dysfunction. [source]

Increased Hepatic and Decreased Urinary Metallothionein in Rats after Cessation of Oral Cadmium Exposure

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2010
Yihuai Liang
Wistar rats of both genders were given CdCl2 in drinking water at daily doses of 0, 2.5, 5.0 or 10.0 mg Cd/kg body-weight for 12 weeks. Half of the animals were then killed; the others were given Cd-free water for the following 16 weeks, i.e. until 28 weeks after start of the experiment (28-week rats). We observed dose-dependent increases in the levels of MT in the tissues of rats 12 weeks after beginning the experiment (12-week rats). After the exposure ceased, levels of MT in the 28-week rats changed in three ways: an increase in the liver, persistence in the kidney cortex and a decrease in the medulla, relative to those levels in their 12-week counterparts. Biomarkers of kidney dysfunction were determined to be urinary MT (UMT) and urinary N -acetyl-,- d -glucosaminidase (UNAG). After 12 weeks, we observed dose-related statistically significant increases in UMT and UNAG in all of the Cd-exposed groups. A statistically significant decrease for UNAG between the 12- and 28-week rats occurred among males at the lowest Cd dose and for UMT in all of the Cd-exposed groups. The unchanged tissue levels of MT in the kidney cortex suggest that decreased UMT is a sign either of (i) decreased transport of Cd-MT from the liver via blood plasma to the renal tubules or (ii) increased tubular reabsorption and recovery of renal tubular function. [source]

Renal concentrating capacity as a marker for glomerular filtration rate

ACTA PAEDIATRICA, Issue 1 2008
Víctor M García Nieto
Aim: We have studied 160 children with a variety of renal diseases, 14 of them with chronic renal failure (CRF), to evaluate maximum urinary osmolality as a predictor of glomerular filtration rate (GFR) testing the hypothesis that a normal GFR is necessary to have a normal urinary concentrating capacity. Methods: All patients had a serum creatinine measured. GFR was calculated according to the Schwartz formula. All patients underwent desmopressin (DDAVP) test to evaluate renal concentrating capacity. Results: Patients with CRF were unable to concentrate the urine beyond 486 mosm/kg whereas all patients with a normal concentrating capacity (urine osmolality > 835 mosm/kg) had a normal GFR. Desmopressin test sensitivity to detect CRF was 100% and specificity 70.5%. A significant negative correlation was found between urinary osmolality after DDAVP administration and serum creatinine levels and between urinary volume corrected by 100 mL of GFR (V/GFR) and urinary osmolality. Conclusion: In our series, a normal concentrating capacity was always associated with a normal GFR while all patients with decreased GFR had a concentrating capacity defect. Thus, in the evaluation of infants and children with renal disease, the finding of a normal urinary concentrating capacity will suggest and intact glomerular and tubular function. [source]