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At least 1,063 records · Page 59Linked to original sources
PubMed1998

Estimation of the glomerular filtration rate in NIDDM patients from plasma creatinine concentration after cimetidine administration.

OBJECTIVE: Glomerular filtration rate (GFR) can be estimated in patients with renal disease from plasma creatinine concentration, age, sex, and body weight according to the formula of Cockcroft and Gault. The hypothesis that this method can be improved when tubular secretion of creatinine is inhibited by cimetidine was studied in NIDDM patients. RESEARCH DESIGN AND METHODS: In 30 outpatients with NIDDM and normo- (n = 10), micro- (n = 9), or macroalbuminuria (n = 11), GFR was measured as the urinary clearance during continuous infusion of 125I-labeled iothalamate. Plasma creatinine concentration was analyzed with an enzymatic assay before and after 800 mg t.i.d. oral cimetidine was given during a 24-h period. RESULTS: Plasma creatinine rose in all patients after cimetidine administration and, as a consequence, the clearance calculated with the Cockcroft-Gault formula fell. The ratio of this formula and GFR decreased from 1.16 +/- 0.20 to 0.97 +/- 0.16 (means +/- SD). This ratio tended to be smaller in the normo- (0.93) than in the micro- (0.98) and macroalbuminuric (1.00) groups. Also, 20 patients with a BMI < 30 kg/m2 had a smaller ratio than those with a BMI > 30 kg/m2 (0.92 vs. 1.07; P < 0.05). Bland and Altman analysis showed a difference of the Cockcroft-Gault formula and GFR of 12.0 +/- 17.4 ml.min-1 (1.73 m2)-1, which decreased to -3.8 +/- 14.8 ml.min-1.(1.73 m2)-1. The same analysis of 24-h creatinine clearance with urine collection and GFR showed larger standard deviations. CONCLUSIONS: GFR can be estimated in an acceptable way from plasma creatinine concentration after cimetidine administration in outpatients with NIDDM. Despite a nonsignificant underestimation in normoalbuminuric and overestimation in overweighted patients, this method is superior to 24-h creatinine clearance with outpatient urine collection.

Administration, Oral↗
PubMed1995

Elimination of the non-ionic X-ray contrast media iodixanol and iohexol in patients with severely impaired renal function.

Iodixanol (Visipaque) and iohexol (Omnipaque) are dimeric and monomeric, respectively, non-ionic X-ray contrast media (CM), with well-characterized pharmacokinetics in healthy volunteers. This study was undertaken to study the pharmacokinetics of the contrast media in patients with severely impaired renal function. A total of 16 patients referred for preoperative abdominal angiography were randomized to form two groups of eight patients, receiving either iodixanol 320 mgI ml-1 or iohexol 350 mgI ml-1. Urine and faeces were sampled before the examination and collected quantitatively for five days afterwards, and blood samples were drawn frequently. The concentrations of iodine and contrast medium in urine and in serum, and the amount of iodine in faeces were determined. Mean baseline creatinine clearance was 13.6 and 9.9 ml min-1 1.73 m-2 in the iodixanol and iohexol groups, respectively. Patients in the iodixanol group received on average 0.34 gI per kg bodyweight (bw) and those in the iohexol group 0.39 gI per kg bw. The semilogarithmic plots of serum concentration of CM vs. time indicated elimination according to a two-compartment model. The mean elimination half-life was 23.0 h for iodixanol and 27.2 h for iohexol, and the mean apparent volume of distribution was similar for the two CM, ranging from 0.20 to 0.30 1 per kg bw. Mean plasma clearance of iodixanol was 10.4 ml min-1 1.73 m-2 and 6.9 ml min-1 1.73 m-2 for iohexol, whereas the mean renal clearances were 8.7 and 6.1 ml min-1 1.73 m-2, respectively. Mean faecal recovery was 8.2% for iodixanol and 6.1% for iohexol, and the respective figures for that in urine were 76.1 and 74.8%. Renal clearance of radiolabelled iothalamate, a marker of glomerular filtration rate (GFR), measured simultaneously, indicated that both CM were eliminated by the kidneys by glomerular filtration only. Thus, both media are suitable as GFR markers.

Aged↗
PubMed1975

Renal function in experimental chronic hydronephrosis. II. Backflow studies with radionuclides.

Studies of backflow in experimental unilateral chronic hydronephrosis in dogs with a known residual renal function and renal pelvic volume were performed with radioactively labelled substances with molecular weights of ca. 600, 5 200 and 68 000 placed in the hydronephrotic renal pelvis. Three different pressure levels in the renal pelvis were used. Isotope concentrations were determined in the thoracic duct lymph, 0lood and urine from the contralateral kidney. The greater part of the test substances appeared to pass to the blood circulation, while a smaller part was found in the lymphatic ducts. The largest molecule, however, was only able to leave the renal pelvis to any appreciable extent at the highest pressure. In kidneys with a low grade of hydronephrosis and well preserved function, a relatively large amount of test substance left the renal pelvis (ca. 10-15%). In more advanced grades of hydronephrosis with greater impairment of renal function, the backflow was considerably less.

Animals↗
PubMed1980

Cellular and renal toxicity of a urographic contrast medium used in high concentration in uremic patients.

The potential toxicity of the urographic contrast medium sodium iothalamate (Conray) has been tested after a bolus injection of 160 ml (66 g iodine) on patients with advanced renal insufficiency. Experiments were performed to investigate the effect of uremic plasma from 5 patients sampled before and after contrast injection on human mononuclear phagocytes cultured in vitro. To investigate the nephrotoxicity, endogenous creatinine clearance was measured before, during and after urography in 25 patients with advanced renal insufficiency (group 1) and in 9 transplanted patients with chronic kidney rejection (group 2). Uremic plasma did not exert further depressive effect on the mononuclear phagocytes after contrast injection when compared to normal plasma indicating no toxicity on this cell model. Neither did the contrast injection exert any depressive effect on creatinine clearance in any of the groups indicating no measurable nephrotoxicity. The urographic technique, particularly the control of fluid balance is found to be very important.

Cell Nucleus↗
PubMed1999

Hypoperfusion in the renal outer medulla after injection of contrast media in rats.

PURPOSE: The effect on regional renal blood was studied after injection of nonionic iso-osmolar iotrolan or ionic high-osmolar iothalamate. MATERIAL AND METHODS: Laser-Doppler flowmetry was used to measure outer medullary (OMBF) and superficial cortical blood flow (CBF) simultaneously in anesthetized rats. Iotrolan (320 mOsm/kg H2O) was injected i.v. at a dose of 600 mg I/kg b.w. (normal dose) over 2 min or 1,600 (high dose) mg I/kg b.w. over 2 or 8 min. Iothalamate (2,580 mOsm/kg H2O) was injected i.v. at a dose of 1,600 (high dose) or 2,900 (extremely high dose) mg I/kg b.w. over 2 min. RESULTS: At the normal dose and 2-min injection of iotrolan, OMBF was reduced by 25+/-9% over 20 min. The high dose of iotrolan injected over 8 min resulted in a reduction in OMBF slightly smaller (17+/-9%) than that induced by the normal dose but lasting longer (30 min). Compared to the normal dose, the high dose and fast (2 min) injection of iotrolan resulted in a greater and more prolonged decrease in OMBF (32+/-6% lasting 50 min). After the high dose of iothalamate (1,600 mg I/kg) there was a decrease in OMBF by 21+/-6%, lasting 30 min. An extremely high dose (2,900 mg I/kg b.w.) gave a heterogeneous response with a mean increase in OMBF of 48+/-24% occurring 60 min after the injection. CONCLUSION: Iso-osmolar and high-osmolar contrast media (CM), at normal and high doses, decrease OMBF, while an extremely high dose of iothalamate may result in an increase. The depression of outer medullary perfusion may have implications for CM-induced acute renal failure in view of the vulnerability of this region to a decrease in oxygen tension.

Animals↗
PubMed1978

The usefulness of 125I-sodium lothalamate as a GFR-indicator in single intravenous injection tests.

Clearance of sodium iothalamate was estimated from plasma elimination curves obtained from 90 patients having varying renal function, after a single intravenous injection of 125I-sodium iothalamate. The usefulness of sodium iothalamate as a GFR-indicator with this technique was tested by a strict statistical comparison with conventional inulin clearance as a reference. The regression line, covering the clearance range 2-163 ml min-1, Clinulin = 1.08.Clsodiumiothalamate-3.7, (n = 84, r = 0.85, SEE = 2.3 ml.min-1) was not significantly different from the identity line, which means (i) that extrarenal elimination could not be detected, and (ii) that I125-sodium iothalamate should be regarded as a useful glomerular marker for single intravenous injection studies. An open two-compartment model of mamillary type was found to give an adequate representation of the plasma disappearance curve. The results are not critically dependent on the choice of approximating function. The method by Sapirstein et al., the method by Nosslin and a power-law method were used for comparison and were found to give the same results. However, the present type of curve fitting analyses requires frequent blood sampling or external counting over a long period in order to give reliable estimates of GFR. This circumstance makes these methods less attractive for clinical use.

Adult↗
PubMed1983

A double-blind clinical trial of iopamidol versus metrizamide for lumbosacral myelography.

A double-blind study was performed to compare metrizamide with the new iodinated water-soluble nonionic contrast medium, iopamidol, for conventional and computerized tomography lumbosacral myelography. Both contrast agents were used in 30 patients, and were equivalent in terms of image quality and clinical accuracy. Headaches and nausea were less severe using iopamidol. The most striking difference was found in adverse neurobehavioral reactions and associated electroencephalographic abnormalities, which were noted in 17% of the metrizamide group but were not seen with the use of iopamidol. Iopamidol appears to be superior to metrizamide for intrathecal applications. An explanation of the differential neurotoxicity is provided.

Clinical Trials as Topic↗
PubMed1984

Significance of contrast enhancement in cranial computerized tomography after subarachnoid hemorrhage.

Eighty patients with subarachnoid hemorrhage underwent computerized tomography (CT) scanning before and after administration of Conray contrast medium. Abnormal enhancement was seen in visual evaluation of the CT scans in 26 cases, in the regions bordering the subarachnoid spaces. Abnormal enhancement was associated with a poor clinical condition, angiographic spasm, and a poor outcome. Measurements of absorption values in the thalamus revealed significant increases in density after contrast enhancement in those patients whose scans showed abnormal enhancement in the regions bordering the subarachnoid spaces on visual evaluation. The authors suggest that the abnormal enhancement is parenchymal, in the gyri, and is not "subarachnoid." They suggest that it is due to gyral hyperemia or extravasation of contrast material into the cortex resulting from breakdown of the blood-brain barrier, or a combination of both factors.

Adult↗
PubMed1975

Apparent volumes of distribution of 125-I-lothalamate and inulin in chickens.

The suitability of utilizing 125-I-iothalamate to estimate the volume of extracellular fluid was assessed in ureterally ligated chickens. Subsequent to intravenous administration the movement of labeled iothalamate from the plasma compartment follows closed two-compartment kinetics and equilibration between vascular and extravascular phases is attained in about 20 minutes. The volume of distribution of 125-I-iothalamate prior to and following the influsion of 0.15 M NaCl (equal to 15% of the estimated ECFV) averaged 23.6 plus or minus 0.61 and 28.4 plus or minus 0.22% of the body weight, respectively. The observed postsaline labeled iothalamate space did not differ statistically from the expected value. When administered simultaneously inulin penetrates into an apparent volume that is 75% of the labeled iothalamate space after 60 minutes. The content of 125-I-iothalamate is relatively high in liver and kidney tissue and suggests that these are major sites where removal of the indicator from plasma occur. It is suggested that 125-I-iothalamate, under appropriate conditions, could be used to measure the plasma volume and the extravascular fluid with which plasma is in rapid diffusion equilibrium.

Animals↗