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At least 181 records · Page 10Linked to original sources

Natural course of kidney function in Type 2 diabetic patients with diabetic nephropathy.

AIMS: To determine the natural course of kidney function and to evaluate the impact of putative progression promoters in Caucasian Type 2 diabetes mellitus (DM) patients with diabetic nephropathy who had never received any antihypertensive treatment. METHODS: A long-term observational study of 13 normotensive to borderline hypertensive Type 2 DM patients with diabetic nephropathy. Glomerular filtration rate (GFR) was measured approximately every year (51Cr-EDTA plasma clearance technique). Albuminuria, blood pressure (BP) and haemoglobin A1c (HbA1c) was determined 2-4 times per year and serum cholesterol every second year. RESULTS: The patients (12 males/one female), age 56+/-9 (mean +/- SD) years, with a known duration of diabetes of 10+/-6 years, were followed for 55 (24-105) (median (range)) months. GFR decreased from 104 (50-126) to 80 (39-112) ml x min(-1) x 1.73 m(-2) (P = 0.002) with a median rate of decline of 4.5 (-0.4 to 12) ml x min(-1) x year(-1). During follow-up, albuminuria rose from 494 (301-1868) to 908 (108-2169) mg/24 h (P = 0.25), while BP, HbA1c and serum cholesterol remained essentially unchanged. In univariate analysis the rate of decline in GFR did not correlate significantly with neither baseline nor mean values during follow-up of BP, albuminuria, HbA1c and serum cholesterol. CONCLUSIONS: Our study suggests that normotensive to borderline hypertensive Type 2 DM patients with diabetic nephropathy have a rather slow decline in kidney function, but we did not unravel the putative progression promoters responsible for the variation in rate of decline in GFR.

Adult↗

Kidney function during hydropenia nad water diuresis in patients with idiopathic recurring nephrolithiasis.

The kidney function of 41 patients with idiopathic recurring kidney stones was investigated by inulin- and PAH-clearances and by measuring the excretion of electrolytes during hydropenia and water diuresis. All patients had normal inulin- and PAH-clearances and normal concentrating capacity as indicated by free water reabsorption (Tc H2O). Seven patients, all of whom had previously been found to have low excretion of magnesium in urine, were unable to dilute their urine. During water diuresis these patients also had lower osmolar clearance and lower excretion of sodium than the other patients. A defective dilution capacity may be of pathogenetic significance for stone formation; the causes of the defect, however, are not clear.

Adult↗

Kidney function in rats with corticomedullary nephrocalcinosis: effects of alterations in dietary calcium and magnesium.

Single-nephron and whole-kidney function were studied in female rats with corticomedullary nephrocalcinosis, and in animals where the lesion had been prevented either by a dietary magnesium supplement or by using a diet with a calcium:phosphorus ratio in excess of 1. At the single-nephron level, rats with nephrocalcinosis had prolonged tubular fluid transit times. Proximal transit time was 19.42 +/- 1.98 (mean +/- S.E. of mean) vs. 11.58 +/- 0.19 s for controls; distal transit time was 62.64 +/- 9.16 vs. 31.50 +/- 1.03 s for controls. Although single-nephron function is altered in nephrocalcinosis, data obtained from rats in metabolism cages indicate that whole-kidney function is largely unaffected by the lesion.

Animals↗

Creatinine excretion rates for evaluation of kidney function in children.

A protein load protocol for evaluation of kidney function was tested in normal children and pediatric renal patients. An overnight, timed urine collection was used for calculation of the baseline creatinine clearance and creatinine excretion rate. One hour following ingestion of a standardized protein meal (baked chicken), a 2-3 h urine collection was begun. The post-protein meal changes in creatinine clearance showed considerable variation in both the normal children and those with renal disorders. In contrast, the rate of excretion of creatinine was consistently increased in the normal children following the protein meal (73.4 +/- 18%; range 48.2%-122.4%). Of 33 renal patients, 14 showed less than a 48% increase in creatinine excretion rate, even though 9 of these children had baseline creatinine clearances within the normal range. These 9 patients have evidence of less than normal quantities of functioning renal tissue. Serial studies over a year on 2 children who presented with acute renal failure showed a progressive increase in creatinine clearance with scant increases in creatinine excretion rate. These studies provide indirect evidence that a less than normal enhancement of the rate of creatinine excretion following a protein load reflects the presence of adaptive glomerular hyperfiltration and hyperperfusion.

Adolescent↗

Nitrite and nitrate levels in patients with cirrhosis of the liver: influence of kidney function and fasting state.

BACKGROUND: Increased serum nitrite/nitrate (NOx) levels, the stable metabolites of nitric oxide (NO), have been reported in patients with cirrhosis. NOx levels, however, are influenced not only by endogenous NO synthesis but also by urinary NOx excretion and dietary intake. We attempted to elucidate factors that influence NOx levels independently of endogenous NO production and to determine the conditions under which NOx levels reflect endogenous production in patients with cirrhosis and healthy controls. METHODS: NOx serum concentrations and urinary NOx excretion were determined by means of the Griess reaction in relation to Child-Pugh score, kidney function, fasting state, and after exposure to tap water. RESULTS: Multifactor regression analysis showed inulin clearance (P = 0.0074) and Child-Pugh score (P = 0.0001) to be independent factors predicting NOx levels in patients with cirrhosis. NOx serum levels correlated negatively with the inulin clearance (P < 0.0001), which deteriorated with progressive loss of liver function. NOx levels decreased by about 30% within a 24-h fasting period. After 24 h fasting urinary NOx excretion was not significantly increased in patients with advanced cirrhosis. CONCLUSION: NOx serum levels, taken as a surrogate for endogenous NO formation, have to be viewed with caution in patients with cirrhosis because they often have impaired kidney function. However, in steady-state conditions after an adequate fasting period NOx levels might be good prognostic markers in patients with cirrhosis since they reflect two possible sequelae of liver insufficiency-namely, increased NO formation and impaired kidney function.

Case-Control Studies↗

Efficacy and safety of revascularization in patients with chronic limb-threatening ischemia by kidney function.

BACKGROUND: The optimal revascularization strategy for patients with chronic limb-threatening ischemia (CLTI) with chronic kidney disease (CKD) remains unknown. We evaluated whether the efficacy and safety of surgical vs endovascular revascularization differ by kidney function. METHODS: In this post hoc secondary analysis of BEST-CLI trial (NCT02060630), 1,704 patients with CLTI were stratified by baseline estimated glomerular filtration rate (eGFR, mL/min/1.73 m&#xb2;): non-CKD (eGFR &#x2265; 90), mild-moderate CKD (eGFR 45-89), advanced CKD (eGFR < 45 or dialysis). The primary outcome was a composite of major adverse limb events (MALE) or death. We estimated the difference in restricted mean time lost (RMTL, in days) adjusted for inverse probability treatment weights. RESULTS: Surgical revascularization was significantly associated with fewer days with MALE or death in non-CKD (RMTL difference: -127.8 days; 95% CI -176.1, -79.6) and mild-moderate CKD (-63.2 days; 95% CI -104.7, -21.8) but not in advanced CKD (-16.4 days; 95% CI -78.8, 46.0; P interaction = .02). This attenuation reflected a diminishing mortality benefit with more severe CKD (P interaction = .01), whereas the association with fewer days with MALE remained consistent across CKD strata (P interaction = .34). Major adverse cardiovascular events and serious adverse events were more common with more severe CKD but did not differ significantly by treatment. CONCLUSIONS: Surgical vs endovascular revascularization was consistently associated with fewer days with MALE across CKD strata. However, its association with mortality varied by kidney function, attenuating the overall benefit for the composite endpoint of MALE or death. These results support individualized revascularization strategies, but require prospective confirmation. TRIAL REGISTRATION: The BEST CLI trial is registered at ClinicalTrials.gov (NCT02060630).

Humans↗

[Pharmacokinetics of sulfamerazine after a single intravenous dose in healthy calves and calves with diarrhea of different severity with consideration of the influence of an existing kidney function restriction].

Blood levels of Sulfamerazine were examined in 16 calves with different severity of diarrhoea in consideration of kidney function and compared with the values of 5 clinically intact animals. Urea and creatinine levels in plasma as well as urea and creatine clearance were tested to check kidney function. A single dose of 60 mg Sulfamerazine/kg body weight was administered to all animals via catheter into the vena jugularis. Blood samples were collected for 48 hours. The mean concentration of Sulfamerazine in calves with severe diarrhoea was significantly higher 24 hours post application than in the healthy control group and in animals with low and middle intensive diarrhoea (healthy animals: 37.61 +/- 7.18 micrograms/ml; animals with severe diarrhoea: 57.3 +/- 7.5 micrograms/ml). Animals with severe diarrhoea showed significantly higher values of half life time of elimination t1/2 (healthy animals: 7.08 +/- 1.25 h; animals with severe diarrhoea: 11.39 +/- 2.11 h) and of area under the curve AUC (healthy animals: 2023.4 +/- 397.21 micrograms*h/ml; animals with severe diarrhoea: 2990.6 +/- 594.9 micrograms*h/ml) than the others. Low and middle intensive diarrhoea has no important influence on the pharmacokinetics of Sulfamerazine.

Animals↗

Kidney function of pyelonephritis patients with impaired renal function treated with mezlocillin.

Ten patients with pyelonephritis and impaired renal function were treated with 2.0 g mezlocillin (Baypen) 8-hourly. They all recovered from urinary tract infection and showed a distinct improvement of their kidney function measured by blood urea nitrogen, serum creatinine and creatinine clearance. No side effects were seen and the blood coagulation remained within normal limits. An overview of the literature on urinary tract infections treated in patients with impaired kidney function is given.

Adult↗

The effect of rapamycin on kidney function in the Sprague-Dawley rat.

The effects of rapamycin (RAPA) on kidney function and histology were investigated in the Sprague-Dawley rat and compared with cyclosporine. Drugs were administered orally in a Cremophor-ethanol formulation for 14 days in two separate studies. RAPA, at 1 mg/kg, had no effect either functionally or histologically on the kidney. At 10 mg/kg, RAPA depressed the gain in body weight by 20% in the rat but had only minor functional disturbances on urine output, plasma creatinine, and creatinine clearance in the kidney. It did not induce any histomorphologic abnormalities. CsA, at 25 mg/kg, produced functional alterations in the kidney including elevated plasma creatinine and depressed clearance of creatinine as well as depressed body weight gain (17%). Histologically, CsA induced proximal tubule damage. These results demonstrate that RAPA (10 mg/kg) does not produce nephrotoxicity in the Sprague-Dawley rat at doses three times higher than its effective immunosuppressive doses established in the rat.

Animals↗

[Unilateral catheterless determination of kidney function in hydronephrosis].

Whereas the value of quantitative separate determination of kidney functioning is undisputed for most urological and nephrological problems, its value for the judgement of hydronephrotic kidneys is doubted by various working groups. Using 15 mongrel dogs, the nuclide excretion at certain times, various calculation intervals and the results of separate functional analysis of hydronephrotic and non-hydronephrotic kidneys were compared. Due to the early nuclide excretion with an advanced secretion peak it is no longer acceptable to use a 2-minute calculation interval for hydronephrotic kidneys in dogs. If the upper limit of the calculation interval is prior to the secretion peak, there will be no overestimation of the hydronephrotic kidneys.

Animals↗

Residual kidney function after unilateral nephrectomy. Pre- and postoperative estimation by renography and clearance measurements.

The residual kidney function was predicted from preoperative renography and determination of the glomerular filtration rate (GFR) in 57 patients undergoing unilateral nephrectomy for cancer, postrenal obstruction or renovascular hypertension. Postoperative GFR measurements were carried out 6-36 months after the operation. In eleven patients where the kidney removed had no function, no significant difference was found between pre- and postoperative GFR values. In 46 patients where the kidney removed had some function, the preoperative estimate was a little too high in only two patients. In this group, the postoperative GFR on an average amounted to 42% above the preoperatively predicted value. We conclude that the combination of 51Cr-EDTA clearance and renography is a reliable, non-invasive method for determination of the minimum residual kidney function before unilateral nephrectomy is carried out.

Adult↗

Differential effect of swelling and anoxia on kidney function and its consequences on the mechanism of action of intracellular organ preservation solutions.

In order to differentiate the effects of swelling and anoxia on kidney function, a canine experimental model is used. After complete liberation of kidneys and their vessels from adjacent tissues, each kidney is submitted to 10 min of hypotonic flushing, or to 60 min of normothermic anoxia. Swelling resulting from these two procedures are equal and permit the study of the consequences of anoxia independently from swelling. Edema is determined by water content and renal blood flow is measured. Kidney function is studied by time of restoration of urinary flow, creatinine, and inulin clearances and fractional water reabsorption. The results show that nonanoxic edema is much less damaging than anoxic edema and consequently that anoxic injury is not the simple consequence of spatial disruption of cell architecture. Since many works have shown the beneficial effects of intracellular organ preservation solutions and consequently that anoxia is better tolerated in the absence of swelling, it can be deduced that injuries induced by anoxia and by swelling are cumulative and that the efficiency of intracellular solutions cannot be attributed solely to the preventive effect on swelling, considered as lethal for the cell.

Animals↗

Comparison of planar and SPECT 99Tcm-dimercaptosuccinic acid scintigraphy in calculating differential kidney function.

An extensive study to compare planar and single photon emission computed tomographic (SPECT) 99Tcm-dimercaptosuccinic acid (DMSA) determination of differential kidney function (DKF) has been carried out. The study has demonstrated that it is possible to use SPECT differential kidney function in place of that obtained using planar scintigraphy. The SPECT DKF value correlated with the planar DKF value. Gradient shaded three-dimensional surface images, reoriented transaxial, sagittal and coronal slices were produced during the same processing method.

Adolescent↗

Kidney function in the severely jaundiced dog.

An attempt was made to prepare experimental models of jaundice in order to study the relation between jaundice and kidney function. Choledochal ligation and surgical division as a conventional means of achieving this aim proved useless in satisfying our requirements. The use of the choledochocaval shunt technique that we devised resulted in successful preparation of models of severe jaundice with a resultant total bilirubin value of 19.2 +/- 8.0 mg/dl at 1 week and 23.9 +/- 8.7 mg/dl 3 weeks postoperatively. Through these models the relation between jaundice and kidney function and the resultant histopathologic features of the kidneys were studied. In the animal models a significantly lower value was obtained for both glomerular filtration rate and renal plasma flow at 1 and 3 weeks postoperatively than in the other groups (undergoing choledochal ligation with division and unilateral nephrectomy, respectively). Histopathologic examination of the kidneys of these animals revealed no marked changes in the glomeruli or Bowman's capsule. Characteristic histopathologic features of the kidneys included swelling and exfoliation of epithelial cells because of reabsorption of bile in the proximal tubules and disintegration of the cell membrane.

Acute Disease↗

Elucidation of kidney function by micropuncture: an historical perspective.

An understanding of the fundamental mechanisms of kidney function awaited the advent of micropuncture techniques. The initial micropuncture study by Wearn and Richards in 1924 presented the first direct evidence that the initial step in urine formation was the process of ultrafiltration at the glomerulus and that certain solutes were reabsorbed in the renal tubules. Subsequent micropuncture studies and the development by Burg and colleagues for in vitro perfusion of surviving tubular segments have provided an enormous amount of information about glomerular function and the transport characteristics of all nephron segments in the normal and diseased kidney.

History, 20th Century↗

Mesangial expansion as a central mechanism for loss of kidney function in diabetic patients.

Diabetic nephropathy leading to kidney failure is a major complication of both type I (insulin-dependent) and type II (non-insulin-dependent) diabetes mellitus, and glomerular structural lesions (especially expansion of the mesangium) may constitute the principal cause of decline in kidney function experienced by a significant fraction of diabetic patients. Although the biochemical bases of these mesangial abnormalities remain unknown, an understanding of the natural history of diabetic nephropathy from a combined structural and functional approach can lead to greater pathophysiological insight. Work in animals has supported the concept that the metabolic disturbances of diabetes mellitus cause diabetic nephropathy, with structural and functional lesions prevented or reversed with improved or normalized glycemic control. Additional research must address this fundamental issue in humans, especially the response of advancing mesangial lesions to improved glycemic control. Factors not directly related to the metabolic perturbations of diabetes may serve to accelerate or diminish the pathophysiological processes of diabetic nephropathy. The elucidation and management of these factors, when coupled with improved glycemic control, may moderate the development or progression of diabetic kidney lesions in humans.

Albuminuria↗

Electric modification of kidney function. The excretion of radiographic contrast media and adriamycin.

The body consists of systems of conductive pathways for ionic flow of current induced by metabolic or injury potentials among tissues and cells. In vivo electrophoresis in biologically closed electric circuits (BCEC) are coupled to the mechanical transports of blood and lymph. Connections also exist with conductive media such as cerebrospinal fluid, bile, and urine. Artificial induction of current was applied over the kidneys in order to study modification of kidney function. It is thought that studies of this kind will increase our understanding of kidney function from a new angle of view and possibly add new therapeutic possibilities. In anesthetized pigs, one kidney was made anodic (electropositive) and the other cathodic (electronegative). Current was applied between electrodes in each ureter. Intravascularly injected, electronegatively charged aminotrizoate and ioxaglate were excreted mainly by the anodic kidney. Nonionic iohexol was urographically excreted by both kidneys. Excretion of electropositively charged Adriamycin by the cathodic kidney was identified macroscopically and by chemical analysis. Functional effects on the kidneys can be induced electrophoretically without causing injury.

Animals↗

Effect of the novel T-selective calcium channel antagonist mibefradil on kidney function in comparison with amlodipine.

In the present study, the renal effects of mibefradil (CAS 116666-63-8), a novel calcium channel antagonist which more selectively blocks T-type than L-type calcium channels, was tested by applying clearance techniques to anaesthetized rats. The effects of mibefradil on kidney function and on arterial blood pressure were compared with those of the long acting dihydropyridine-type calcium antagonist amlodipine (CAS 88150-42-9). The results show that, within a dosage range of 0.1 to 1.0 mg/kg i.v., mibefradil induced a dose-dependent decrease of arterial blood pressure. Kidney function was not significantly affected at a dose of 0.1 mg/kg. By increasing the dose to 0.3 mg/kg, mibefradil induced a significant increase in urine flow, renal sodium, chloride and potassium excretion. Also fractional sodium and chloride excretions were significantly enhanced at this dose. The diuretic and saluretic effects of mibefradil were accompanied by a significant increase in the glomerular filtration rate. At the highest dose of 1 mg/kg used, the blood pressure lowering effect of mibefradil was most pronounced and glomerular filtration rate rose only slightly and not significantly. At this dose, the enhancement of urine flow and urinary electrolyte excretion was smaller than at the dose of 0.3 mg/kg. The actions of mibefradil were qualitatively similar to those of the dihydropyridine derivate amlodipine which at a dose of 0.3 mg/kg produced nearly identical renal effects to mibefradil, but exerted stronger antihypertensive effects. This study demonstrates that mibefradil shares with amlidopine the property to induce, at appropriate doses, diuretic and saluretic effects with a concomitant increase in glomerular filtration rate.

Amlodipine↗