Prediction of renal function improvement in azotemic patients using glomerular filtration rate from 99mTc-DTPA renal scan: An observational study.

ABSTRACT: This study aimed to evaluate the ratio of glomerular filtration rate (GFR) from 99mTc-diethylenetriamine-pentaacetic acid dynamic renal scan (GFRSCAN) to estimated GFR (eGFR) as a predictor of renal function improvement in patients with azotemia.A retrospective review of medical records was conducted to identify consecutive patients with newly discovered or aggravated azotemia who underwent 99mTc-diethylenetriamine-pentaacetic acid renal scan. Significant renal function improvement was defined as ≥100% and ≥10 mL/min improvement of eGFR at 12 weeks compared to eGFR on the day of renal scan (eGFR0). The GFRSCAN/eGFR0 ratio was evaluated as a predictor of significant renal function improvement using logistic regression and receiver operating characteristic (ROC) curve analyses. Added value of the GFRSCAN/eGFR0 ratio in the prediction of significant renal function improvement were demonstrated by adjusting for best clinical predictor variables.The eligibility criteria were met by 224 patients, among whom 22 patients (9.8%) showed significant renal function improvement. The odds ratios of the GFRSCAN/eGFR0 ratio for predicting significant renal function improvement were 1.76 (95% confidence interval [CI]: 1.26-2.45, P < .001) in the univariable analysis and 1.70 (95% CI: 1.19-2.42, P = .003) after adjusting for clinical variables. The area under the ROC curve of the GFRSCAN/eGFR0 ratio for predicting significant renal function improvement was 0.762 (95% CI: 0.648-0.871). The addition of the GFRSCAN/eGFR0 ratio to the best clinical prediction model raised the area under the ROC curve from 0.726 to 0.794, and this increment was statistically significant (P = .02).The GFRSCAN/eGFR ratio can predict renal function improvement in patients with azotemia. Future prospective studies are necessary to validate its potential clinical utilities.

Compare serum creatinine versus Renal 99mTc-DTPA scan determined glomerular filtration rates in veterans with traumatic spinal cord injury and meurogenic bladder.

OBJECTIVE: This observational study: (a) compared serum creatinine (estimated glomerular filtration rate (EGFR)) to renal isotope 99mTc-DTPA (GFR) determined glomerular filtration rate, and evaluated whether either method (b) better determined the state of renal function, and (c) predict urinary tract infection (UTI), renal and urological structural lesions or mortality in veterans with traumatic spinal cord injury (SCI) and neurogenic bladder (NGB). DESIGN: Observational study. SETTING: VA Medical Center affiliated with Oklahoma University. PARTICIPANTS: Veterans with SCI and regularly followed in SCI clinic. Demographic and clinical data, as well as, EGFR, GFR, blood urea nitrogen (BUN) and serum creatinine levels, and presence of UTI, renal and urinary bladder lesions on renal nuclear scan, renal ultrasound, and cystoscopy studies were recorded. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Urological lesions, UTI, and Mortality. RESULTS: For 161 patients with SCI and NGB the mean ± SD for EGFR was 104 ± 36 and 84 ± 32 for GFR. EGFR and GFR were positively correlated (r = 0.34, P = 0.015). GFR was significantly (P < 0.05) more sensitive and specific in determining renal functional state. Neither measures were significant indicator for UTI, renal or urological lesions; GFR was a significant predictor of risk of death (1.2 times increase in risk per 10 unit drop in GFR) even after adjusting for age (P = 0.040). CONCLUSION: While GFR and EGFR are comparable measures of glomerular filtration, GFR was a more informative measure of renal functional state and risk of mortality than EGFR. Neither method predicted the presence of UTI related renal or urological lesions.

Scintigraphic assessment of renal function in steel plant workers occupationally exposed to lead.

OBJECTIVES: Occupational exposure to lead may produce kidney damage, but existing data on the dose range associated with nephrotoxicity are inconclusive. We here assessed renal function under conditions of low to moderate lead exposure using renal scintigraphy. METHODS: Fifty-three male foundrymen (exposed group) and fourty male office workers (control group) from a steel plant were included in the study. Glomerular and tubular renal function were assessed by means of (99m)Tc-DTPA and (99m)Tc-EC clearance, respectively. Urinary markers of glomerular dysfunction (albumin) and tubular damage (α1-microglobulin (α1M), ß2-microglobulin (ß2M), retinol-binding protein (RBP), N-acetyl-ß-glucosaminidase (NAG) activity) were determined using latex beads tests or colorimetry. The lead concentration in blood was measured with atomic absorption spectrometry. RESULTS: The blood lead concentrations were 145.8 (121.3-175.3) and 39.3 (35.1-44.1) µg/l (geometric mean, 95(th) CI, p<0.001) in the exposed and control groups, respectively. Subjects exposed to lead presented with increased (99m)Tc-DTPA clearance (158.3 (148.4-168.8) vs. 135.9 (127.9-144.4) ml/min; p<0.01) and urinary albumin excretion (7.61 (6.28-9.22) vs. 4.78 (4.05-5.65) mg/g creatinine; p<0.001). (99m)Tc-EC clearance and excretion of α1M, ß2M, RBP and NAG were not significantly different between the groups. Significant correlations between (99m)Tc-DTPA clearance and blood lead concentrations (r=0.45; p<0.01) and between urinary albumin excretion and blood lead concentrations (r=0.71; p<0.001) were noted. CONCLUSIONS: Use of renal scintigraphy in present study revealed measurable alterations of renal function under the conditions of low-level lead exposure and suggest that increased glomerular filtration may be an early indicator of kidney damage in subjects occupationally exposed to lead.

Validation of a new standardized cystatin C turbidimetric assay: evaluation of the three novel CKD-EPI equations in hypertensive patients.

OBJECTIVES: Analytical and clinical performances of the new standardized cystatin C particle-enhanced turbidimetric immunoassay (PETIA) using DiaSys reagents on Olympus AU2700® analyzer were evaluated. DESIGN AND METHODS: We have studied imprecision, linearity, limit of detection and limit of quantification of this new immunoassay. Method comparison was assessed in relation to results generated by the standardized Siemens-particle-enhanced nephelometric immunoassay (PENIA). In order to evaluate the clinical relevance of this assay, estimated glomerular filtration rate (GFR) was calculated using MDRD, CKD-EPI creatinine, CKD-EPI cystatin C 2012 and CKD-EPI creatinine-cystatin C 2012 equations and compared to GFR measured using urinary clearance of (99m)Tc-DTPA in 100 hypertensive patients. RESULTS: Cystatin C measurements using DiaSys reagents have reliable analytical performances and are comparable to the standardized Siemens-PENIA method (bias of 0.01 mg/L). The mean measured GFR was 90.0±29.7 mL/min/1.73 m². Bias and accuracy of the three CKD-EPI equations were better than the MDRD. Both CKD-EPI creatinine-based and cystatin C-based formulae had similar bias, precision and accuracy. The combined creatinine-cystatin C equation was significantly more accurate and precise than the CKD-EPI creatinine equation in patients with GFR above 60 mL/min/1.73 m². CONCLUSIONS: The use of cystatin C in a combined equation with creatinine could improve the accuracy of eGFR in the reference interval.

Comparison of estimating equations for the prediction of glomerular filtration rate in kidney donors before and after kidney donation.

The aim of this study is to investigate the usefulness of the GFR-estimating equations to predict renal function in kidney donors before and after transplantation. We compared the performance of 24-hour-urine-based creatinine clearance (24 hr urine-CrCl), the Cockcroft-Gault formula (eGFRCG), the Modification of Diet in Renal Disease equation (eGFRMDRD), and the Chronic Kidney Disease Epidemiology Collaboration equation (eGFRCKD-EPI) with technetium-diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) clearance (mGFR) in 207 potential kidney donors and 108 uninephric donors. Before donation, eGFRCKD-EPI showed minimal bias and did not show a significant difference from mGFR (P = 0.65, respectively) while 24 hr urine-CrCl and eGFRMDRD significantly underestimated mGFR (P<0.001 for each). Precision and accuracy was highest in eGFRCKD-EPI and this better performance was more dominant when renal function is higher than 90 mL·min(-1)·1.73 m(-2). After kidney donation, eGFRMDRD was superior to other equations in precision and accuracy in contrast to before donation. Within individual analysis, eGFRMDRD showed better performance at post-donation compared to pre-donation, but eGFRCKD-EPI and eGFRCG showed inferior performance at post-donation. In conclusion, eGFRCKD-EPI showed better performance compared to other equations before donation. In a uninephric donor, however, eGFRMDRD is more appropriate for the estimation of renal function than eGFRCKD-EPI.

[Comparison of four methods for measuring glomerular filtration rate by inulin clearance in healthy individuals and patients with renal failure]. / Comparación de cuatro métodos de medición de la tasa de filtración glomerular con depuración de inulina en individuos sanos y en pacientes con insuficiencia renal.

BACKGROUND: A proper measurement of renal function is important for diagnosis and stratification of kidney disease. Several methods have been used to predict glomerular filtration rate, however the results have been variable depending on the population studied. We aimed to compare the performances of 4 glomerular filtration rate tests with inulin clearance in patients with chronic renal insufficiency and in healthy subjects. METHODS: Inulin clearances performed in 51 individuals with stable renal function were selected. For each of them, we computed 4 estimates: the 24-hour creatinine clearance, technetium (99mTc-DTPA) clearance, Cockcroft-Gault and Levey formulas. Their respective performance was assessed by correlation (Pearson's correlation coefficient) and agreement (Bland and Altman method). RESULTS: Each glomerular filtration rate test closely correlated with inulin clearance. Nevertheless, all GFR tests displayed considerable lack of agreement with lower limits ranging from 15 to 42 ml / min, for comparison with inulin-technetium and inulin with Levey formula, respectively and upper limits of agreement that could range from 20 to 56 ml / min, for comparison with inulin-technetium and Inulin with Levey formula,respectively. CONCLUSION: The measurement of glomerular filtration rate determined via different methods shows a wide range of variation when compared with inulin clearance, which should be considered in daily clinical practice during the evaluation of renal function.

The preliminary experimental and clinical study of the relationship between the pigment gallstone and intestinal mucosal barrier.

AIMS: To investigate the relations between the formation of pigment gallstone and the function of the intestinal mucosal barrier, as well as the underlying mechanism. METHODS: Eighty guinea pigs were randomly divided into three groups in which they were respectively given normal diet, gallstone-causing diet, and gallstone-formation diet with a supplementary intestinal mucosal protection compound known as glutamine. The model of pigment gallstone was established after 8 weeks of dietary administration. Indices about the function of the intestinal mucosal barrier and bacterial translocation were measured. Clinical cases were divided into three groups: control, cholesterol gallstone, and pigment gallstone, where the levels of plasma diamine oxidase (DAO), plasma endotoxin and the excretion rates of technetium 99m-diethylene triamine pentaacetic acid (99mTC-DTPA) in the urine of each group were measured. RESULTS: In the pigment gallstone group, the level of plasma DAO and endotoxin, the excretory ratio of lactulose and mannitol in urine, the bacterial translocation ratio in the celiac lymph nodes and the activities of beta-glucuronidase increased comparing to the control group. The gallstone-formation rate for the intestinal mucosal protection group (GLN) decreased, and other indices, except the activity of beta-glucuronidase, were all lower than that of gallstone-formation group. In the clinical experiment, the levels of plasma DAO and endotoxin, as well as the excretory rate of 99mTC-DTPA in urine were higher in the patients with gallstones than that in the control group. CONCLUSIONS: The formation of pigment gallstone was related to the abnormal function of the intestinal mucosal barrier. The abnormality in the function of the intestinal mucosal barrier probably induced the formation of gallstone by a bacterial translocation mechanism.

[Determination of intestinal permeability in cholelithiasis patients by oral administration of technetium-99m-diethylenetriaminepentaacetatic acid].

OBJECTIVE: To investigate the intestinal permeability of patients with cholelithiasis of different types. METHODS: Technetium-99m-diethylenetriaminepentaacetatic acid (99mTc-DTPA) at the dose of 185 MBq (5 mCi) was administered orally to 56 patients of cholelithiasis, 15 cases of cholesterol stone (CS group) and 41 cases of pigment stone (PS group) based on the cross section of the stone during operation, and 17 healthy controls. A 24 h urine collection was obtained after the ingestion of the tracer to calculate the urinary excretion of DTPA. RESULTS: The mean percentage of the total ingested dose of 99mTc-DTPA excreted in a 24 h urinary excretion was 5.0%+/-3.6% in the CS group, not significantly different from that in the control group (4.5%+/-3.4%. F=2.18, P>0.05), and the mean percentage of the total ingested dose of 99mTc-DTPA excreted in a 24 h urinary excretion of the PS group was 10.5%+/-6.9%, significantly higher than that in the control group (F=7.62, P<0.05), showing a significantly increase of intestinal permeability (P<0.05). CONCLUSION: The intestinal permeability of the patients of pigment stone is higher than that of the healthy subjects. Hyperpermeability may be a factor of the pathogenesis of pigment stone.

Small-bowel permeability in collagenous colitis.

OBJECTIVE: Collagenous colitis (CC) is a chronic inflammatory bowel disease that affects the colon. However, some patients with CC present with accompanying pathologic small-bowel manifestations such as coeliac disease, defects in bile acid absorption and histopathologic changes in small-intestinal biopsies, indicating that CC is a pan-intestinal disease. In small-intestinal disease, the intestinal barrier function may be impaired, and the permeability of the small intestine altered. The purpose of this research was to study small-bowel function in patients with CC as expressed by intestinal permeability. MATERIAL AND METHODS: Ten patients with CC and chronic diarrhoea participated in the study. Coeliac disease was excluded by small-bowel biopsy and/or serology. Intestinal permeability was assessed as urinary excretion (ratios) 2, 4 and 6 h after ingestion of 14C-labelled mannitol (14C-mannitol) and 99mTc-labelled diethylenetriamine-pentaacetic acid (99mTc-DTPA). Data were compared with the results from healthy controls. RESULTS: No difference was found between groups in urinary excretion of 14C-mannitol and 99mTc-DTPA after 2, 4 or 6 h, respectively. Likewise, no significant differences in the 99mTc-DTPA/14C-mannitol ratios between patients and controls were detected after 2 h: 0.030 (0.008-0.130) versus 0.020 (0.007-0.030), p = 0.19, after 4 h: 0.040 (0.009-0.180) versus 0.020 (0.008-0.040), p = 0.14 or after 6 h: 0.040 (0.012-0.180) versus 0.020 (0.010-0.040), p = 0.17. CONCLUSIONS: No alterations in intestinal permeability in patients with CC could be demonstrated. Impairment of the integrity of the mucosa of the small bowel and the presence of a general dysfunction of the small intestine in patients with CC seem unlikely.

Oral (99m)Tc-DTPA simultaneous determination of duodenobiliary reflux and intestinal permeability in patients after choledocholithotomy plus T-tube drainage.

BACKGROUND: The high choledocholithiasis recurrence rate after choledocholithotomy plus T-tube drainage is related to biliary bacterial infection. These bacteria are from the intestine, either via the major duodenal papilla, or the penetrating intestinal mucosa. It is therefore possible that duodenobiliary reflux and increased intestinal permeability exist in patients who have undergone choledocholithotomy. This study was undertaken to find the evidence of duodenobiliary reflux and to assess intestinal permeability in these patients. METHODS: Twenty-one patients who underwent choledocholithotomy plus T-tube drainage 2 months ago, and 11 healthy volunteers (controls) took orally 185MBq of (99m)Tc-DTPA. The patients' bile was collected in the next 2 hours via a T-tube and the (99m)Tc-DTPA radioactivity in the bile was counted. Intestinal permeability was evaluated by measuring the 24-hour urinary excretion rate of ingested (99m)Tc-DTPA in both patients and controls. RESULTS: In 6 of the 21 patients, radioactivity in the bile was detected. The intestinal permeability was significantly higher in patients (11.45%+/-6.16%) than that in controls (3.61%+/-1.63%, t=3.28, P<0.05). CONCLUSIONS: Duodenobiliary reflux exists in patients who have undergone choledocholithotomy plus T-tube drainage. The intestinal permeability is higher in these patients than in healthy subjects. Duodenobiliary reflux and increased intestinal permeability may be factors of cholelithiasis recurrence.

Use of plasma clearance of technetium Tc 99m pentetate to estimate renal clearance during postnatal development in pigs.

OBJECTIVE: To compare renal clearance of technetium Tc 99m pentetate with plasma clearance by use of a glomerular filtration rate technique in pigs from 3 to 24 weeks of age. ANIMALS: 24 female pigs. PROCEDURE: At the time of investigation, 5 pigs were 3 weeks old, 6 pigs were 6 weeks old, 8 pigs were 12 weeks old, and 5 pigs were 24 weeks old. Plasma clearance of technetium Tc 99m pentetate was measured by the use of a single injection technique followed by collection of multiple blood samples until 5 hours after the injection. Simultaneously, urine was collected through a urinary catheter, and the renal clearance of technetiumTc 99m pentetate was calculated. Plasma clearance of technetium Tc 99m pentetate was correlated with the renal clearance (r = 0.95). Plasma clearance was higher than renal clearance at all ages (mean, 5.8%), indicating extrarenal clearance of technetium Tc 99m pentetate or methodologic errors. Volume of distribution increased with increasing age but decreased as a fraction of body weight. CONCLUSIONS: Plasma clearance of technetium Tc 99m pentetate estimates renal clearance with acceptable precision when using single injection technique and multiple biood samples in pigs from 3 to 24 weeks of age.

A comparison of bedside renal function estimates and measured glomerular filtration rate (Tc99mDTPA clearance) in cancer patients.

BACKGROUND: The aim of this study was to compare measured glomerular filtration rate (GFR) with estimates of GFR derived from the population pharmacokinetic methods of Martin and Wright, and the creatinine clearance (CrCl) estimates of Cockcroft and Gault, and Jelliffe. PATIENTS AND METHODS: GFR was determined by technetium-99m diethyl triamine penta-acetic acid (Tc99DTPA) clearance in adult cancer patients. Height, actual body weight and serum creatinine were measured, and GFR and CrCl estimates calculated. RESULTS: One hundred and twenty-two patients were included. The mean measured GFR was 87 ml/min (range 30-174 ml/min). The mean bias (mean percentage error) was 2, 1, -10 and -17%, and the mean precision (mean absolute percentage error) was 18, 19, 21 and 23% for the Wright, Martin, Cockcroft and Gault, and Jelliffe formulas, respectively. The Martin formula significantly underestimates GFR for females (mean bias -10%) and overestimates GFR for males (mean bias 8%) (P <0.001 for bias of males versus females). The Wright and Martin formulas significantly overestimate GFR <50 ml/min (mean bias 39 and 30%; P = 0.03 and 0.05, respectively) and all formulas underestimate GFR >100 ml/min (mean bias -18, -16, -24 and -32% for Wright, Martin, Cockcroft and Gault, and Jelliffe formulas, respectively; P <0.001). CONCLUSIONS: All the assessed estimates for renal function were found to have significant limitations.

Protozoon infections and intestinal permeability.

Intestinal permeability (IP) studies using some macromolecules have been assumed to demonstrate the intactness of intestinal mucosa. The aim of the present study is to determine the changes in IP among patients with protozoan infections. Thirty nine patients with protozoan infections and ten healthy controls were enrolled in the study. Protozoa were diagnosed by Native-lugol, Richie and Trichrome staining of faeces. IP was evaluated by diethyl triamine penta acetic acid labeled with 99m Technetium (99mTc labeled DTPA) assay. The IP was found to have increased in patients with protozoan infections compared with control patients (7.20+/-5.52 vs. 4.47+/-0.65%, P=0.0017). The IP values were 9.91+/-10.05% in Giardia intestinalis group, 6.81+/-2.25% in Blastocystis hominis group, 5.78+/-2.84% in Entamoeba coli group. In comparison with the control group, the IP was significantly higher in G. intestinalis and B. hominis patients (P=0.0025, P=0.00037, respectively), but not in E. coli patients. In conclusion, the IP increases in patients with G. intestinalis and B. hominis but not with E. coli infection. This finding supports the view that IP increases during the course of protozoan infections which cause damage to the intestinal wall while non-pathogenic protozoan infections have no effect on IP. The increase in IP in patients with B. hominis brings forth the idea that B. hominis can be a pathogenic protozoan.

A simple method for measuring severely reduced glomerular filtration rate.

OBJECTIVE: The purpose of this study was to develop a simpler method to measure severely reduced glomerular filtration rate (GFR) for patients with a GFR below 30 mL/min. METHOD: The GFR was measured in 24 patients using both the 51Cr EDTA slope-intercept method (the conventional method) and 99mTc-DTPA with our proposed simpler GFRn method. RESULTS: The correlation coefficient was 0.92 between the 2 methods, with a slope of 0.97 and an intercept of 2 mL/min. CONCLUSION: Our simplified method for measuring GFR is accurate for most patients with severely reduced GFR. Errors are acceptably small in patients with severely reduced GFR when edema or dehydration are present. If extrarenal (liver) clearance is significant, however, a urine sampling method is required for an accurate GFR measurement.

Effect of propranolol on the factors promoting bacterial translocation in cirrhotic rats with ascites.

Bacterial translocation appears to be an important mechanism in the pathogenesis of spontaneous infections in cirrhosis. Cirrhotic patients are commonly treated with beta-adrenoceptor blockers, but the impact of this treatment in the factors promoting bacterial translocation has not been investigated. This study was aimed at investigating in cirrhotic rats with ascites the effect of propranolol on intestinal bacterial load, transit, and permeability of the bowel and on the rate of bacterial translocation. Bacterial translocation to mesenteric lymph nodes and intestinal bacterial overgrowth, permeability (urinary excretion of (99m)Tc-diethylenetriaminepentaacetic acid [(99m)Tc-DTPA]), and transit (geometric center ratio of (51)Cr) were assessed in 29 rats with carbon tetrachloride (CCl(4)) cirrhosis and 20 controls. These variables were then measured in 12 placebo- and in 13 propranolol-treated ascitic cirrhotic rats. Bacterial translocation was present in 48% of the cirrhotic rats and in none of the controls. Cirrhotic rats with intestinal bacterial overgrowth had a significantly higher rate of translocation and slower intestinal transit than those without it. Among the 15 rats with overgrowth and a (99m)Tc-DTPA excretion greater than 10%, 15 had translocation and 2 had bacterial peritonitis. Only 1 of the 14 rats with either intestinal overgrowth or a (99m)Tc-DTPA excretion greater than 10% presented translocation. Compared with the placebo group, propranolol-treated animals had significantly lower portal pressure, faster intestinal transit, and lower rates of bacterial overgrowth and translocation. In ascitic cirrhotic rats, bacterial translocation results from intestinal overgrowth and severe damage to gut permeability. In this setting, intestinal overgrowth is associated with intestinal hypomotility. Propranolol accelerates the intestinal transit, decreasing the rates of bacterial overgrowth and translocation.

A comparison of the renal handling of 99Tcm-DTPA and 99Tcm-MAG3 in hypertensive patients using an uptake technique.

The renal uptake and outflow of 99Tcm-DTPA and 99Tcm-MAG3 were compared by analysing renal studies performed in two different departments, but with analysis techniques and computer programs using algorithms that were almost identical. Comparison was performed by a retrospective review of results from patients who were referred for renal investigations because of hypertension but who had apparently normal kidneys. The analysis of tracer outflow rates in the form of whole-kidney transit times and renal cortical transit times showed no significant difference between the two tracers. The fractional uptake rate of tracer for each patient (both kidneys) indicated that MAG3 was extracted from the blood 3.3 times faster than DTPA in patients aged 20-69 years, with a lower ratio above the age of 70. When used to measure relative renal function, there was no overall difference between the two tracers. The fractional uptake rates were also converted to flow rates, producing values of 95.8 +/- 28.0 ml.min(-1).1.73 m-2 for DTPA and 320 +/- 75 ml.min(-1).1.73 m-2 for MAG3, in hypertensive patients aged 20-40 years. These values showed a good correlation with other published GFR and MAG3 clearance rates (obtained using blood sampling methods) in normal patients of similar ages.

Transient alteration in intestinal permeability to technetium Tc99m diethylenetriaminopentaacetate during the prodromal stages of alimentary laminitis in ponies.

OBJECTIVES: To determine whether mucosal permeability is altered during the prodromal stages of alimentary laminitis. ANIMALS: 15 healthy adult ponies. PROCEDURES: intestinal permeability was evaluated for control ponies (n = 5) and for ponies 4 to 12 (n = 5) and 20 to 28 (n = 5) hours after administration of carbohydrate overload. Mucosal permeability was determined by measuring the percentage of orally administered technetium Tc99m diethylenetriaminopentaacetate (99mTc-DTPA) excreted in urine during an 8-hour period, then measuring blood radioactivity at hourly intervals. Plasma endotoxin-like activity was measured by use of a chromogenic Limulus amebocyte assay. RESULTS: Urinary excretion of 99mTc-DTPA was 2.45% of administered dose for control ponies, and was 16.67% of administered dose 4 to 12 hours and 3.57% of administered dose 20 to 28 hours after administration of carbohydrate. CONCLUSIONS: A marked but transient increase in intestinal permeability was observed early in the prodromal stages of alimentary laminitis. CLINICAL RELEVANCE: Absorption of substances from the intestine may be an initiating event in alimentary laminitis.

Early glomerular effects of contrast media in rats: evaluation with a simple method.

The aim of this study was to evaluate the early effects of high and low-osmolar contrast media on glomerular function in rats by using a new method based on the measurement of the urinary excretion of 99mTc-DTPA. Thirty-six Sprague-Dawley male rats were examined: nine rats were injected with diatrizoate (ionic high-osmolar contrast medium), nine rats with iohexol (nonionic low-osmolar contrast medium), and nine rats with saline as controls. The urinary excretion of 99mTc-DTPA in the first minutes after i.v. injection was assumed as an index of glomerular filtration rate. A lower urinary excretion of 99mTc-DTPA was found in rats treated with contrast media in comparison with control rats. This effect was more evident after diatrizoate but was statistically significant also after iohexol. In conclusion, a reduction in the glomerular filtration rate probably occurs in the first few minutes after contrast media administration. The measurement of urinary excretion of 99mTc-DTPA could be a simple method to detect acute glomerular effects due to contrast media or to other drugs.

Induction of an experimental Fanconi syndrome in mice: its effect on the glomerular filtration function studied by 99mTc-DTPA.

An experimental mice model of maleate (MAL)-induced Fanconi syndrome has been used to test 99mTc-DTPA ability to detect hampered glomerular filtration rate (GFR) early in drug-induced Fanconi syndrome. In fact, declining GFR has been reported both in idiopathic and acquired Fanconi syndrome. The above MAL model shows urine biochemistry changes similar to those reported in patients suffering from Fanconi syndrome. Moreover, biodistribution study and whole-body autoradiographies performed after IV injection of 99mTc-DTPA in MAL and control mice show significantly delayed pharmacokinetics of the above radiopharmaceutical in a MAL dose-dependent effect. After administration of a MAL dose of 6 mM/kg BW, the 5-min biodistribution of 99mTc-DTPA, a radiopharmaceutical freely excreted by glomerular filtration, is significantly changed in all organs. In blood of MAL mice, 27.62 +/- 2.86% of the injected dose is still circulating compared to 13.67 +/- 1.22% of the injected dose in control mice, and only 1.37 +/- 0.31% of the injected dose has been excreted in urine of MAL mice compared to 24.66 +/- 4.12% of the injected dose in urine of control mice. The obtained results suggest that 99mTc-DTPA may be efficient both in the early detection of abnormal GFR in acquired Fanconi syndrome after application of a nephrotoxic treatment, and in the follow-up of patients in recovery phase after discontinuation of the therapy.