Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “IOTHALAMIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Absorption of iothalamate after oral administration and absorption enhancement by amino acids in dogs and rats.

The oral absorption of iothalamate and the effect of amino acids on its absorption were studied in 6 dogs and 6 rats using a simple HPLC assay. The results showed that iothalamate was absorbed in dogs, averaging 9.9, 8.5, and 10.0 per cent following the administration of 40 and 100 mg kg-1 of iothalamic acid capsules and 50 mg kg-1 of sodium iothalamate solution, respectively. The absorption from the capsule was slower and more sustained than that from the solution. In rats, the absorption appeared to be dose-independent (averaging about 4.2 per cent) in the dose range of 20-800 mg kg-1. The low bioavailability obtained was mainly due to the high polarity of iothalamate molecules as suggested by the GI recovery and in vitro partition studies. Among several amino acids tested as possible ion-pair formers, only homoarginine hydrochloride increased the partition of iothalamate into chloroform layer. However, both homoarginine hydrochloride and arginine hydrochloride at the amino acid/iothalamate molar ratio of 25 were found to significantly enhance (about 70 per cent) the iothalamate absorption in dogs. The in situ rat small intestinal loop study indicated that the absorption-enhancing effect of arginine was sodium dependent. At the sodium chloride concentration of 0.09 M, no significant increase in the absorption was observed, while at the concentration of 0.3 M or higher, a marked increase (about twofold) was obtained in both upper and lower intestine. Thus, the mechanism of the amino acids in facilitating the iothalamate absorption may be more closely related to the active amino acid transport system rather than the possible increase in lipophilicity of the ion-pair formed. The potential use of such naturally occurring, relatively non-toxic amino acids for increasing the GI absorption of water-soluble weak acids or bases through ion-pair formation remains to be fully investigated.

Administration, Oral↗
PubMed1987

Animal evaluation of technetium-99m triamide mercaptide complexes as potential renal imaging agents.

Technetium-99m mercaptoacetylglycylglycylglycine (MAG3), a [99mTc]triamide mercaptide (N3S) compound has been synthesized in an attempt to obviate the stereochemistry problems associated with the diamide dimercaptide (N2S2) ligands. Because initial studies have been promising, the terminal glycine on the MAG3 compound has been varied to create a new series of N3S compounds. Twelve new N3S complexes were initially screened in mice and the more promising complexes, 99mTc mercaptoacetylgylcylglycyl-glycine [( 99mTc]MAG3), 99mTc mercaptoacetylgylcylglycyl-L-alanine [( 99mTc]MAG2-Ala), and both complexes of 99mTc mercaptoeacetylglycylglycyl-L-asparagine [( 99mTc]MAG2-Asn) and 99mTc mercaptoacetylglycylglycyl-L-glutamine [( 99mTc]MAG2-Gln), were further evaluated in rats utilizing constant infusion blood clearances, extraction efficiencies and protein binding assays. The renal excretion of all these complexes compared favorably with simultaneously administered [131I]OIH and [125I]iothalamate. The triamide mercaptide complexes represent a new ligand class for 99mTc, which may provide a variety of complexes for the evaluation of renal tubular function.

Animals↗
PubMed1986

A comparison of simplified and standard methods for the measurement of glomerular filtration rate and renal tubular function.

Two methods of measuring the clearance of 99Tcm DTPA, OIH and iothalamate were compared with standard techniques of measuring the clearance rates of inulin and sodium para-aminohippurate. The best correlation was between the clearance of subcutaneously injected radiolabelled iothalamate or 99Tcm DTPA and that of inulin. 99Tcm DTPA and 131I OIH clearances measured by a two blood sample technique did not give as good a correlation with inulin and PAH clearances respectively. When measurements of GFR and tubular function were repeated on the same patients the changes measured by inulin and PAH clearances did not correlate with those measured by the two blood sample technique using 99Tcm DTPA and OIH. Our results suggest that the clearance of subcutaneously injected iothalamate or DTPA can replace inulin clearance measurements. The two blood sample technique of measuring DTPA and OIH clearance does not directly reflect inulin and PAH clearance and is insufficiently reproducible to be used to follow changes in renal function.

Adult↗
PubMed1995

99mTc-MAG3 kinetics in the normal pig. A comparison to 131I-OIH and 125I-iothalamate after single injection and during continuous infusion.

An invasive comparative study of some pharmacokinetic aspects of 99mTc-mercaptoacetyltriglycine (MAG3), 131I-orthoiodohippurate (OIH), and 125I-iothalamate (iothalamate) was performed in six pigs 0-150 min after a simultaneous single injection (SI) and during a subsequent 90 min of continuous infusion (CI). The total plasma clearance and the renal clearance of MAG3 were about 75% that of OIH. The renal clearance of MAG3 was about 2 1/2 times the glomerular filtration rate. The distribution volume of MAG3 was 71% that of iothalamate and only 47% that of OIH. There was a significant hepatic plasma clearance of MAG3 of 5.9 ml min-1 and 3.9% of the injected dose was excreted in the bile. HPLC analysis revealed that technetium was excreted in urine and bile mainly labelled to MAG3. The average red blood cell (RBC) binding after single injection/during continuous infusion was 1.0%/2.3% for MAG3, 13.5%/9.0% for OIH, and 3.1%/5.3% for iothalamate. The binding of OIH to RBC in arterial blood increased from 8% at 1 min post-injection to 21% at 150 min post-injection. The RBC binding was higher in the renal vein, indicating incomplete back diffusion from RBC to plasma. The protein binding was 90% for MAG3, 49% for OIH and 16% for iothalamate. The renal plasma extraction of MAG3 was constant but significantly smaller after SI (0.54) than during CI (0.62). Following SI, the renal plasma extraction of OIH decreased continuously from 0.85 to 0.52, 3-150 min post-injection. On the average there was no significant difference in renal plasma extraction after SI and during CI of either OIH (0.72 versus 0.77) or iothalamate (0.26 versus 0.27). It is concluded that MAG3 is preferential to OIH as a tracer for renal function studies using a single injection technique mainly due to the constant renal extraction of MAG3.

Animals↗
PubMedDate not supplied

Toxicity of X-ray contrast media in cell cultures.

Monolayer cell culture techniques for neuronal and glial cells and fibroblasts were used for the investigation of the direct toxicity of x-ray contrast media. The effect of various concentrations of sodium diatrizoate, methylglucamine salts of diatrizoate, iothalamate, iodamide, metrizamide, iocarmate, ioserate, and ioglycamate were studied. The intravenous biliary contrast medium--ioglycamate--was most toxic to all cell types. All the contrast media studied were somewhat toxic to neurons in the concentration of 50 mmol/l and showed variable glial toxicity. In equiosmolar concentrations the contrast media studied showed toxicity on neurons in the following order: iothalamate, diatrizoate, iodamide, ioserate, iocarmate, ioglycamate. Fresh metrizamide solution in equimolar concentrations showed the least toxic effects on neurons but interfered considerably with the growth and survival of glial cells. Metrizamide solution proved to be highly toxic to neurons when refrigerated for two weeks. Methylgucamine iocarmate produced a peculiar swelling of fibroblasts.

Cell Survival↗
PubMedDate not supplied

Osmotic effect and solubility of amipaque (metrizamide) in the gastrointestinal tract.

Loops of small intestine in seven rabbits were resected with intact pedicle and ligated at both ends after instillation of 0.5 ml of Gastrografin, Urografin 76%, Amipaque 370 mg I/ml, Amipaque 170 mg I/ml or physiologic saline. After half an hour, the amount of fluid in the loops containing Gastrografin and Urografin 76% increases about twice as much as in the loops containing Amipague with the same iodine concentration because of their greater osmolality. The differences between the loops with isotonic Amipaque (170 mg I/ml) and physiologic saline are not significant. Precipitation occurs when sodium and meglumine salts of diatrizoate, metrizoate, iothalamate, iocarmate and ioglycamate are mixed with 0.05 N HCl. No precipitation occurs with Amipaque, not even when the HCl concentration is as high as 1.2 N. Precipitation occurs when Gastrografin is added to gastric juices with low pH, but is not seen with Amipaque should be a suitable contrast medium for gastrointestinal examinations because of its low osmolality and toxicity and good solubility in gastric juice.

Animals↗
PubMedDate not supplied

Pharmacokinetics of 125I-iothalamate and 131I-o-iodohippurate in man.

The pharmacokinetics of 125I-iothalamate (IOT125I) and 131I-o-iodohippurate (OIH131I) have been studied in patients with varying degrees of renal insufficiency. Both compounds have been shown to obey two-compartment model kinetics after intravenous administration. The clearances are closely related to renal function, but poor correlations were obtained between renal function and compartmental distribution characteristics. This study provides further evidence that IOT125I and OIH131I may be used as indicators of renal function in patients after a single intravenous injection.

Blood Urea Nitrogen↗
PubMedDate not supplied

Activation of serum complement by contrast media.

Evidence is presented for the activation of serum complement by contrast media, in vitro and in vivo. Activation as a function of concentration was measured and the increasing order of effectiveness was found to be metrizamide, iothalamate, diatrizoate, acetrizoate, iodipamide and iopanoate. This order is the same as for protein binding and enzyme inhibition. The activation mechanism for iodipamide, and by inference for the other compounds, does not involve gamma-globulin aggregation. Serial daily injections in normal dogs resulted in substantial declines in serum complement over several days. Guinea pigs which were depleted of serum complement with cobra venom factor were found to be no less sensitive to lethal doses of iodipamide than those with normal complement. Implications of these findings are discussed.

Acetrizoic Acid↗
PubMed1977

Error dependent on renal function when monoexponential equation assumed. Serum clearances of 125I-iothalamate and 131I-o-iodohippurate.

An example from the literature has been used to demonstrate errors involved in calculating drug clearance by inappropriate use of the apparent drug distribution volume Vdext. The Vdext is always an overestimate of the true volume of distribution in a multicompartment system, and the degree of overestimation in using it to calculate clearance for such a system will increase as renal function increases. Drug dosages calculated on the basis of overestimated clearance values may give rise to overdosage in normal individuals, or therapeutic failure in severely uremic patients. Problems associated with the use of an oversimplified pharmacokinetic model for clearance calculations are discussed, together with the concept of model-independent calculations.

Humans↗
PubMed1998

Can continuous intraperitoneal infusion of 125I-iothalamate and 131I-hippuran be used for measurement of GFR in conscious rats?

We previously described a method to measure GFR in conscious spontaneously voiding rats. This method circumvents the need for anesthesia and for bladder instrumentation. It's main principle is the correction of renal 125I-iothalamate clearance for incomplete urine collection by the ratio of plasma and renal clearance of co-infused 131I-Hippuran. A disadvantage of this technique is the requirement of an intra-arterial catheter for infusion of the renal function tracers. We therefore tested whether intraperitoneal infusion of 125I-iothalamate and 131I-Hippuran can be used for such a GFR measurement in conscious spontaneously voiding rats. We found that during intraperitoneal administration, stable plasma levels of 131I-Hippuran could be obtained. However, urinary recovery of 131I-Hippuran was incomplete (66 +/- 32%), leading to a significant overestimation of GFR by 140 +/- 13% in comparison with the GFR measured by the intra-arterial technique. Thus intraperitoneal infusion of renal function tracers cannot replace intra-arterial infusion.

Animals↗
PubMed1976

Antibiotics and chemotherapeutics in renal lymph. An experimental study in dogs.

Renal lymph concentrations of ampicillin, carbenicillin, cephacetrile, cephaloridine, and nitrofurantoin were determined in a total of 28 dogs during constant infusion of the drugs together with [125I]iothalamate and [131I]o-iodohippurate for simultaneous determination of glomerular filtration rate and effective renal plasma flow. The lymph concentrations of the radiolabeled clearance substances, serving as a standard were compared to those of the antimicrobial agents. The lymph concentrations of the four antibiotics were all significantly lower than the respective simultaneous arterial plasma concentrations. The nitrofurantoin lymph concentrations were equal to the simultaneous plasma concentrations. It is concluded that the renal lymph concentrations of antibiotics and chemotherapeutics do not exceed the simultaneous plasma concentrations unless the urine flow is obstructed.

Ampicillin↗
PubMed1978

Use of the double-isotope, single-injection method for estimating renal function in normal and polybrominated biphenyl-exposed dairy cows.

A method is described for conducting a rapid and efficient renal function test in dairy cattle. The method, adapted from methods used for man and dogs, utilizes radiolabeled 131I-sodium iodohippurate to determine effective renal plasma flow (ERPF) and 125I-sodium iothalamate to determine glomerular filtration rate (GFR). The mean GFR for adult cattle was determined to be 2.8 +/- 0.4 ml/kg/minute with a biological half-life of 35.5 +/- 1.4 minutes. The mean ERPF was found to be 10.5 +/- 1.9 ml/kg/minute with a half-life of 17.9 +/- 0.6 minutes. These values are comparable with those in man, but are lower than values in dogs. A toxcity study was done with dairy cattle exposed to polybrominated biphenyls (PBB). Efforts were made to determine the amount of time required for kidney lesions to develop and, if possible, to delineate the potential site of action of PBB. Apparently PBB do not affect GFR or ERPF, even though they produce nephrotoxic effects. Potential mechanisms to explain these results are described.

Animals↗
PubMed1996

Angiotensin-converting enzyme inhibition-induced changes in hippurate renography and renal function in renovascular hypertension.

UNLABELLED: We studied the mechanism of angiotensin-converting enzyme (ACE) inhibition-induced changes in hippurate renography of the poststenotic kidney. METHODS: Ten male mongrel dogs, six with unilateral and four with bilateral renal artery stenosis, were equipped with renal artery blood flow probes and catheters in the aorta, atrium and both renal veins. RESULTS: Enalaprilat (10 mg intravenously) in conscious dogs with renal artery stenoses produced changes in all stenotic (n = 11) but not in nonstenotic kidney 123I-hippurate renograms (n = 6). Renographic changes correlated significantly with initiation of intrarenal 131I-hippurate retention, a decrease in mean arterial pressure (MAP), renal extraction of 131I-hippurate and 125I-iothalamate (r = 0.68, r = 0.62, r = 0.84, r = 0.83, respectively) but not with renal blood flow changes (r = 0.34). Furthermore, renal uptake of 131I-hippurate and 125I-iothalamate decreased in stenotic kidneys with a grade II renogram (-52 +/- 11% and -79 +/- 6%, respectively). Iodine-125-hippurate autoradiograms of stenotic kidneys during ACE inhibition showed tracer retention mainly in the proximal tubular cells. Results during osmotic diuresis supported our findings. CONCLUSION: Angiotensin-converting enzyme inhibition-induced hippurate retention curves of poststenotic kidneys appear to result from a sequence of events. A decrease in MAP combined with efferent vasodilation leads to a decrease in intraglomerular capillary pressure. This decrease in pressure causes a decrease in glomerular filtration rate and proximal tubular urine flow. This decrease in turn hampers tubular hippurate transit and transport across the luminal membrane, leading to intrarenal hippurate retention and, in more severe cases, decreased renal hippurate uptake.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Age-dependent enzymuria, proteinuria and changes in renal blood flow and glomerular filtration rate in rats.

The time course of urinary excretion of two enzymatic indicators of renal damage, N-acetyl-beta-D-glucosaminidase (NAG) and alanine aminopeptidase (AAP) was measured in female Wistar rats at different ages. NAG and AAP are localized at different sites of the nephron and are released into the urine when kidney damage occurs. Total protein flow, urinary volume and creatinine flow were also determined. In a parallel experiment, the effect of aging on renal blood flow (RBF) and glomerular filtration rate (GFR) was examined in young (1.5-month) adult (3-month) and elderly (20-month) female rats. Clearance following a single injection of [131I]o-iodohippurate (hippuran, OIH) was used for the measurement of effective RBF and as an index of tubular cell function. [125I]Iothalamate (IOT) clearance was used to measure GFR. With advancing age, an increase in NAG and AAP urinary flow appeared. The increases in protein excretion were greater than and previous to those of enzyme excretion. It is shown that absolute RBF and GFR (ml/min) in old rats are greater than in young or adult animals. When absolute RBF or GFR was divided by kidney weight (ml/min/g) no clearance changes appeared in any age group studied; only when clearance was expressed in relation to body weight (ml/min/100 g), a decrease in RBF and GFR was evidenced. This indicates that the rate of increase of both RBF and GFR with age is similar to that of kidney weight and lower than that of body weight. The present findings indicate that urinary markers of renal injury increase with age, whereas GFR and RBF only decrease when expressed as clearance related to body weight.

Aging↗