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Kidney International Jun 2013Chronic kidney disease risk factors may associate with the estimated glomerular filtration rate (eGFR) differently than with the measured GFR. To examine this, we... (Comparative Study)
Comparative Study
Chronic kidney disease risk factors may associate with the estimated glomerular filtration rate (eGFR) differently than with the measured GFR. To examine this, we evaluated 1150 patients (mean age 65 years) in two community cohorts for risk factors, measured GFR by iothalamate clearance, and eGFR based on creatinine (Cr), cystatin C (CysC), or both. The interaction between each risk factor and eGFR (relative to measured GFR) identified risk factor associations with eGFR along non-GFR pathways. In a subset of 40 patients with two visits, the mean coefficient of variation was 8.2% for measured GFR, 6.4% for eGFRCr, 8.2% for eGFRCr-CysC, and 10.7% for eGFRCysC. The measured GFR was better correlated with eGFRCr-CysC (r, 0.74) than eGFRCr (r, 0.70) or eGFRCysC (r, 0.68). Lower measured GFR associated with lower 24-hour urine creatinine, albuminuria, hypertension, diabetes, higher triglycerides, and higher uric acid. Lower eGFRCr had these same associations except for an association with higher 24-hour urine creatinine along a non-GFR pathway. Lower eGFRCysC and eGFRCr-CysC also had these same associations but also associated with obesity, albuminuria, hypertension, diabetes, higher triglycerides, higher C-reactive protein, and higher uric acid along non-GFR pathways. Thus, cystatin C improves estimation of GFR over creatinine alone; however, the association between most of the risk factors and GFR was more accurate by eGFR based on creatinine alone. This is explained by the association of these risk factors with the non-GFR determinants of cystatin C.
Topics: Aged; Albuminuria; Biomarkers; Creatinine; Cystatin C; Diabetes Mellitus; Female; Glomerular Filtration Rate; Humans; Hypertension; Iothalamic Acid; Kidney; Linear Models; Male; Middle Aged; Minnesota; Models, Biological; Multivariate Analysis; Predictive Value of Tests; Renal Insufficiency, Chronic; Risk Factors; Triglycerides; Uric Acid
PubMed: 23423253
DOI: 10.1038/ki.2013.7 -
Kidney International Aug 2011Tolvaptan and related V(2)-specific vasopressin receptor antagonists have been shown to delay disease progression in animal models of polycystic kidney disease. Slight... (Clinical Trial)
Clinical Trial
Tolvaptan and related V(2)-specific vasopressin receptor antagonists have been shown to delay disease progression in animal models of polycystic kidney disease. Slight elevations in serum creatinine, rapidly reversible after drug cessation, have been found in clinical trials involving tolvaptan. Here, we sought to clarify the potential renal mechanisms to see whether the antagonist effects were dependent on underlying renal function in 20 patients with autosomal dominant polycystic kidney disease (ADPKD) before and after 1 week of daily split-dose treatment. Tolvaptan induced aquaresis (excretion of solute-free water) and a significant reduction in glomerular filtration rate (GFR). The serum uric acid increased because of a decreased uric acid clearance, and the serum potassium fell, but there was no significant change in renal blood flow as measured by para-aminohippurate clearance or magnetic resonance imaging (MRI). No correlation was found between baseline GFR, measured by iothalmate clearance, and percent change in GFR induced by tolvaptan. Blinded post hoc analysis of renal MRIs showed that tolvaptan significantly reduced total kidney volume by 3.1% and individual cyst volume by 1.6%. Preliminary analysis of this small cohort suggested that these effects were more noticeable in patients with preserved renal function and with larger cysts. No correlation was found between changes of total kidney volume and body weight or estimated body water. Thus, functional and structural effects of tolvaptan on patients with ADPKD are likely due to inhibition of V(2)-driven adenosine cyclic 3',5'-monophosphate generation and its aquaretic, hemodynamic, and anti-secretory actions.
Topics: Adult; Antidiuretic Hormone Receptor Antagonists; Benzazepines; Biomarkers; Contrast Media; Creatinine; Diuresis; Female; Glomerular Filtration Rate; Hormone Antagonists; Humans; Iothalamic Acid; Kidney; Magnetic Resonance Imaging; Male; Middle Aged; Minnesota; Organ Size; Polycystic Kidney, Autosomal Dominant; Potassium; Receptors, Vasopressin; Renal Circulation; Time Factors; Tolvaptan; Treatment Outcome; Uric Acid; p-Aminohippuric Acid
PubMed: 21544064
DOI: 10.1038/ki.2011.119 -
Reproductive Biomedicine Online Jan 2021What are the long-term costs and effects of oil- versus water-based contrast in infertile women undergoing hysterosalpingography (HSG)? (Comparative Study)
Comparative Study
RESEARCH QUESTION
What are the long-term costs and effects of oil- versus water-based contrast in infertile women undergoing hysterosalpingography (HSG)?
DESIGN
This economic evaluation of a long-term follow-up of a multicentre randomized controlled trial involved 1119 infertile women randomized to HSG with oil- (n = 557) or water-based contrast (n = 562) in the Netherlands.
RESULTS
In the oil-based contrast group, 39.8% of women needed no other treatment, 34.6% underwent intrauterine insemination (IUI) and 25.6% had IVF/intracytoplasmic sperm injection (ICSI) in the 5 years following HSG. In the water-based contrast group, 35.0% of women had no other treatment, 34.2% had IUI and 30.8% had IVF/ICSI in the 5 years following HSG (P = 0.113). After 5 years of follow-up, HSG using oil-based contrast resulted in equivalent costs (mean cost difference -€144; 95% confidence interval [CI] -€579 to +€290; P = 0.515) for a 5% increase in the cumulative ongoing pregnancy rate compared with HSG using water-based contrast (80% compared with 75%, Relative Risk (RR) 1.07; 95% CI 1.00-1.14). Similarly, HSG with oil-based contrast resulted in equivalent costs (mean cost difference -€50; 95% CI -€576 to +€475; P = 0.850) for a 7.5% increase in the cumulative live birth rate compared with HSG with water-based contrast (74.8% compared with 67.3%, RR 1.11; 95% CI 1.03-1.20), making it the dominant strategy. Scenario analyses suggest that the oil-based contrast medium is the dominant strategy up to a price difference of €300.
CONCLUSION
Over a 5-year follow-up, HSG with an oil-based contrast was associated with a 5% increase in ongoing pregnancy rate, a 7.5% increase in live birth rate and similar costs to HSG with water-based contrast.
Topics: Contrast Media; Cost-Benefit Analysis; Ethiodized Oil; Female; Follow-Up Studies; Humans; Hysterosalpingography; Iothalamic Acid; Pregnancy; Pregnancy Rate; Randomized Controlled Trials as Topic
PubMed: 33077355
DOI: 10.1016/j.rbmo.2020.09.015 -
Clinical Journal of the American... Jun 2013Although iothalamate clearances have been widely used to measure GFR, the need for transportation of plasma samples under refrigerated conditions obviates its use in...
BACKGROUND AND OBJECTIVES
Although iothalamate clearances have been widely used to measure GFR, the need for transportation of plasma samples under refrigerated conditions obviates its use in resource-poor situations. Spots of blood or plasma dried on filter paper may provide a solution.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
Using a validated HPLC technique, iothalamate in dried blood spots of different hematocrits was measured. GFR was measured over 5 hours in 10 subjects with CKD using dried plasma spots and standard methods.
RESULTS
Lower hematocrit produced greater area of blood spreading and lowered the recovery of iothalamate from dried blood spots. However, the relationship between iothalamate concentrations in dried plasma spots and plasma showed a regression slope of 0.95 (95% confidence interval=0.92-0.98, P<0.001). Bland-Altman plot of paired sample points (n=116) showed a bias of -4 μg/ml and limits of agreement of -38 to +30 μg/ml. The relationship between GFRs using dried plasma spots and plasma methods also showed an excellent relationship (slope of 0.95, 95% confidence interval=0.82-1.17). Bland-Altman plot of paired GFRs showed a bias of 2 ml/min, with limits of agreement of -6 to +10 ml/min. Precision was generally between 5% and 10%, and accuracy was within 5%.
CONCLUSIONS
Although dried blood spots are unsuitable for studies among those patients with very low hematocrit, dried plasma spots correct for this limitation, and this small pilot study shows that it is a reasonably reliable method for quantifying iothalamate and subsequently, determining GFR.
Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Chromatography, High Pressure Liquid; Dried Blood Spot Testing; Female; Glomerular Filtration Rate; Hematocrit; Humans; Iothalamic Acid; Kidney; Male; Middle Aged; Pilot Projects; Predictive Value of Tests; Renal Insufficiency, Chronic; Reproducibility of Results; Spectrophotometry, Ultraviolet; Time Factors
PubMed: 23411426
DOI: 10.2215/CJN.10471012 -
British Journal of Pharmacology Jul 19731. In the anaesthetized dog bombesin had a potent antidiuretic effect, and sometimes arrested urine flow completely. Threshold doses, by i.v. infusion, were of the order...
1. In the anaesthetized dog bombesin had a potent antidiuretic effect, and sometimes arrested urine flow completely. Threshold doses, by i.v. infusion, were of the order of 0.5-1 (ng/kg)/minute. Antidiuresis was the result of a reduction in glomerular filtration rate provoked by a fall in intraglomerular hydrostatic pressure. This, in its turn, was due to afferent vasoconstriction.2. The spasmogenic effect of bombesin on the smooth muscle of the afferent arterioles was directly demonstrated by the radioactive microspheres technique and indirectly by the (85)Kr washout method and by [(3)H]-p-aminohippurate clearance. The vascular compartment most sensitive to bombesin was that of the outer cortical zone, especially in its external half.3. Filtration fraction decreased under the influence of bombesin, indicating that the effect of the polypeptide on postglomerular arterioles was, if present, only of minor importance.4. At high infusion rates (above 6 (ng/kg)/min), bombesin produced a decrease in [(3)H]-p-aminohippurate extraction. The effect of the polypeptide on fractional distal delivery of sodium varied with the dose: at moderate infusion rates it decreased, at high infusion rates it increased. The total glucose appearing in urine following a glucose load was sharply reduced by bombesin. However, the glomerular filtration rate/maximum tubular glucose transport ratio did not show any appreciable change.5. Afferent vasoconstriction produced by bombesin was accompanied by an intense activation of the renin-angiotensin system, as shown by a conspicuous increase in renin secretion, followed by increases in renin activity and angiotensin II concentration in arterial blood. When bombesin was infused into one renal artery only the infused kidney showed afferent vasoconstriction and increased renin secretion. The time-course of renin secretion produced by bombesin depended upon the rate of infusion of the polypeptide. At low rates an increased renin secretion was observed throughout the infusion period, at high rates two peaks of renin secretion could be seen, one at the beginning of the infusion, the other soon after the infusion had finished.6. The mechanism of action of bombesin is discussed and the interest of the polypeptide as a possible hormonal regulator of the circulation and function of the kidney is pointed out.
Topics: Anesthesia, General; Angiotensin II; Animals; Anura; Blood Flow Velocity; Catheterization; Creatinine; Diuresis; Dogs; Female; Glomerular Filtration Rate; Glucose; Hippurates; Iothalamic Acid; Kidney; Male; Microspheres; Peptides; Renin; Sodium; Ureter; Urinary Bladder
PubMed: 4357960
DOI: 10.1111/j.1476-5381.1973.tb08352.x -
PloS One 2014N-acetylcysteine (NAC) or sodium bicarbonate (NaHCO3), singly or combined, inconsistently prevent patients exposed to radiographic contrast media from developing... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
N-acetylcysteine (NAC) or sodium bicarbonate (NaHCO3), singly or combined, inconsistently prevent patients exposed to radiographic contrast media from developing contrast-induced acute kidney injury (CI-AKI).
OBJECTIVE
We asked whether intravenous isotonic saline and either NaHCO3 in 5% dextrose or else a high dose of NAC in 5% dextrose prevent CI-AKI in outpatients exposed to high-osmolal iodinated contrast medium more than does saline alone.
METHODS
This completed prospective, parallel, superiority, open-label, controlled, computer-randomized, single-center, Brazilian trial (NCT01612013) hydrated 500 adult outpatients (214 at high risk of developing CI-AKI) exposed to ioxitalamate during elective coronary angiography and ventriculography. From 1 hour before through 6 hours after exposure, 126 patients (group 1) received a high dose of NAC and saline, 125 (group 2) received NaHCO3 and saline, 124 (group 3) received both treatments, and 125 (group 4) received only saline.
RESULTS
Groups were similar with respect to age, gender, weight, pre-existing renal dysfunction, hypertension, medication, and baseline serum creatinine and serum cystatin C, but diabetes mellitus was significantly less prevalent in group 1. CI-AKI incidence 72 hours after exposure to contrast medium was 51.4% (257/500), measured as serum creatinine > (baseline+0.3 mg/dL) and/or serum cystatin C > (1.1 · baseline), and 7.6% (38/500), measured as both serum creatinine and serum cystatin C > (baseline+0.3 mg/dL) or > (1.25 · baseline). CI-AKI incidence measured less sensitively was similar among groups. Measured more sensitively, incidence in group 1 was significantly (p<0.05) lower than in groups 2 and 3 but not group 4; adjustment for confounding by infused volume equalized incidence in groups 1 and 3.
CONCLUSION
We found no evidence that intravenous isotonic saline and either NaHCO3 or else a high dose of NAC prevent CI-AKI in outpatients exposed to high osmolal iodinated contrast medium more than does saline alone.
TRIAL REGISTRATION
ClinicalTrials.gov NCT01612013.
Topics: Acetylcysteine; Acute Kidney Injury; Administration, Intravenous; Contrast Media; Coronary Angiography; Female; Humans; Iothalamic Acid; Male; Middle Aged; Osmolar Concentration; Sodium Bicarbonate
PubMed: 25254489
DOI: 10.1371/journal.pone.0107602 -
AJR. American Journal of Roentgenology Sep 2012The purpose of this study is to determine a concentration of iodinated contrast media in saline and 5% dextrose in water (D5W) for organ hydrodissection, a technique...
OBJECTIVE
The purpose of this study is to determine a concentration of iodinated contrast media in saline and 5% dextrose in water (D5W) for organ hydrodissection, a technique used to physically separate and protect tissues adjacent to thermal ablations.
MATERIALS AND METHODS
A total of 28 samples were prepared from 1:1000-1:1 iohexol or iothalamate meglumine contrast media in either normal saline or D5W. Samples alone or juxtaposed with a homogeneous liver-mimicking phantom were imaged by CT using 80-120 kVp and 10-300 mAs. Mean CT numbers and noise were measured from the fluid, background air, phantom adjacent to the fluid, and phantom distant from the fluid. Visibility was determined from the contrast-to-noise ratio between the fluid and phantom, whereas streaking artifact was quantified by relative noise in the phantom. Measures were individually fit using multiple linear regression to determine an optimal contrast-to-fluid ratio for increased visualization without streaking. Contrast media- and blood-doped saline and D5W were also tested to determine whether such doping altered their electrical conductivity.
RESULTS
Iohexol concentration most influenced CT number; volumetric ratios of 1:1000-1:1 produced 20 HU to over 3000 HU. CT numbers were weakly dependent on x-ray tube voltage, whereas contrast-to-noise ratio and streaking artifacts were somewhat dependent on tube output. An optimal ratio of iohexol in fluid was determined to be 1:50. There was no significant difference between the electrical impedances of doped and pure saline or D5W (p > 0.5, all cases).
CONCLUSION
A 1:50 ratio of iohexol in saline or D5W provides an optimal combination of increased visibility on CT without streaking artifacts.
Topics: Aged; Artifacts; Catheter Ablation; Contrast Media; Dissection; Female; Glucose; Humans; Iohexol; Iothalamate Meglumine; Liver; Male; Middle Aged; Multidetector Computed Tomography; Phantoms, Imaging; Radiographic Image Enhancement; Radiography, Interventional; Sodium Chloride
PubMed: 22915411
DOI: 10.2214/AJR.11.7999 -
Kidney International Sep 2002Inulin remains the gold standard for measurements of fluid reabsorption (Jv) and single nephron glomerular filtration rate (SNGFR) in micropuncture experiments. However,... (Comparative Study)
Comparative Study
BACKGROUND
Inulin remains the gold standard for measurements of fluid reabsorption (Jv) and single nephron glomerular filtration rate (SNGFR) in micropuncture experiments. However, the method used to measure cold inulin in nanoliter samples is time-consuming, while the use of radiolabeled inulin is disadvantaged by possible radioactive contamination, disposal of radioactive material and cost of the isotope. It has been reported that non-radiolabeled iothalamate may be a suitable alternative for estimation of whole kidney GFR. The present study tested whether iothalamate can be used to measure Jv in microperfusion and free-flow micropuncture experiments.
METHODS
Superficial loops of Henle (LOH) were perfused from late proximal to early distal tubules with an end-like proximal solution. In the first set of experiments, the perfusate contained both iothalamate (1.9 mmol/L) and 3H-methoxy-inulin (50 microCi. mL(-1)). To test if iothalamate was able to detect changes in Jv, two additional sets of experiments were performed: (1) mannitol (61 mmol/L) was added to the perfusate to partially replace NaCl, a condition known to inhibit Jv; (2) LOH of remnant kidneys were perfused, which in previous experiments we showed to have a higher Jv. Lastly, free-flow micropuncture experiments were performed by infusing iothalamate IV at 18.3 mg. h(-1). Iothalamate analysis in nanoliter samples of renal tubular fluid obtained in vivo was performed by capillary electrophoresis (CE).
RESULTS
In the first set of experiments, liquid scintillation counting of 3H-methoxy-inulin versus iothalamate analysis with CE resulted in almost identical calculated perfusion rates (20.4 +/- 0.6 vs. 20.6 +/- 0.7 nL. min(-1), N = 20) and tubular fluid/perfusate ratios (TF/P; 1.35 +/- 0.04 vs. 1.36 +/- 0.04) and thus also Jv (5.17 +/- 0.50 vs. 5.38 +/- 0.59 nL. min(-1)). In the mannitol experiments, iothalamate measurements showed that the addition of mannitol significantly reduced Jv from 4.98 +/- 0.40 (N = 19) to 0.72 +/- 0.58 nL. min(-1) (N = 33; P < 0.0001). Iothalamate determinations by CE were able to detect a significant increase in Jv in LOH of remnant rats perfused at 40 nL. min(-1)[from to 8.40 +/- 0.73 (N = 20) in sham-operated to 17.8 +/- 2.9 nL. min(-1) (N = 6) in remnant animals; P < 0.0001]. In free flow micropuncture experiments the ratio of tubular fluid to plasma iothalamate (TF/P) along the proximal tubule was 1.62 +/- 0.10 (N = 15).
CONCLUSIONS
These data demonstrate that iothalamate can replace inulin to measure Jv in microperfusion and free-flow micropuncture experiments. Since iothalamate analysis by CE technique is a fast, easy and highly reproducible technique, it may become the gold standard method for the detection of fluid reabsorption in microperfused nephron segments.
Topics: Animals; Contrast Media; Electrophoresis, Capillary; Glomerular Filtration Rate; Inulin; Iothalamic Acid; Loop of Henle; Male; Nephrons; Perfusion; Rats; Rats, Sprague-Dawley; Tritium
PubMed: 12164892
DOI: 10.1046/j.1523-1755.2002.00510.x -
American Journal of Physiology. Renal... Jan 2007Idiopathic hypercalciuria (IH) is common among calcium stone formers (IHSF). The increased urinary calcium arises from increased intestinal absorption of calcium, but it...
Idiopathic hypercalciuria (IH) is common among calcium stone formers (IHSF). The increased urinary calcium arises from increased intestinal absorption of calcium, but it is unclear whether increased filtered load or decreased renal tubular reabsorption of calcium is the main mechanism for the increased renal excretion. To explore this question, 10 IHSF and 7 normal subjects (N) were studied for 1 day. Urine and blood samples were collected at 30- to 60-min intervals while subjects were fasting and after they ate three meals providing known amounts of calcium, phosphorus, sodium, protein, and calories. Fasting and fed, ultrafiltrable calcium levels, and filtered load of calcium did not differ between N and IHSF. Urine calcium rose with meals, and fractional reabsorption fell in all subjects, but the change was significantly higher in IHSF. The changes in calcium excretion were independent of sodium excretion. Serum parathyroid hormone levels did not differ between N and IHSF, and they could not account for the greater fall in calcium reabsorption in IHSF. Serum magnesium and phosphorus levels in IHSF were below N throughout the day, and tubule phosphate reabsorption was lower in IHSF than N after meals. The primary mechanism by which kidneys ferry absorbed calcium into the urine after meals is via reduced tubule calcium reabsorption, and IHSF differ from N in the magnitude of the response. Parathyroid hormone is not likely to be a sufficient explanation for this difference.
Topics: Adult; Calcium; Diet; Dietary Proteins; Fasting; Female; Humans; Iothalamic Acid; Kidney; Kidney Tubules; Magnesium; Male; Middle Aged; Nephrolithiasis; Parathyroid Hormone; Phosphates; Postprandial Period; Sodium
PubMed: 17210796
DOI: 10.1152/ajprenal.00115.2006 -
Neurotoxicity of nonionic iodinated water-soluble contrast media in myelography: experimental study.AJNR. American Journal of Neuroradiology 1983The neurotoxicity of four contrast media--iotrol, iopamidol, metrizamide, and ioglunide--was studied by subarachnoid injection in 14 rabbits implanted with four cerebral...
The neurotoxicity of four contrast media--iotrol, iopamidol, metrizamide, and ioglunide--was studied by subarachnoid injection in 14 rabbits implanted with four cerebral electrodes. Thirty-four recordings and quantitative analyses were carried out of spontaneous electrical brain activity, seizure activity, and visual- and somatosensory-evoked potentials. The quantitative study of the electroencephalograms showed differences among the four products. All four of the contrast media induced a general slowing of the electroencephalographic activity and, 30 min after injection, slow waves and a shift of the spectrum energy toward the slow frequencies (0.5-3.5 Hz). The slowing of the recording was the least marked with iotrol and recovery of a normal recording was also quickest with iotrol. The quantitative study of electrical seizures and paroxysms revealed higher seizure activity with ioglunide and iopamidol. The study of the evoked potentials does not permit any distinction among the four contrast agents. Metrizamide induced the fewest seizures, but, considering the slow waves and the seizures, iotrol appears to be the least neurotoxic.
Topics: Animals; Brain; Contrast Media; Electroencephalography; Evoked Potentials; Iodobenzenes; Iodobenzoates; Iopamidol; Iophendylate; Iothalamic Acid; Metrizamide; Myelography; Rabbits; Seizures; Triiodobenzoic Acids
PubMed: 6419559
DOI: No ID Found