Comparison of plasma clearance of [51Cr]CrEDTA based on three, two and single samples to measure the glomerular filtration rate in patients with solid tumors: a prospective cross-sectional analysis.

OBJECTIVES: [51Cr]CrEDTA is used to measure the Glomerular Filtration Rate (GFR) in different clinical conditions. However, there is no consensus on the ideal number of blood samples to be taken and at what time points to measure its clearance. This study aimed to compare Slope Intercept (SI) and Single-Sample (SS) methods for measuring GFR in patients with solid tumors, stratified by age, GFR, and Body Mass Index (BMI). METHODS: 1,174 patients with cancer were enrolled in this prospective study. GFR was calculated by the SI method using blood samples drawn 2-, 4-, and 6-hours after [51Cr]CrEDTA injection (246-GFR). GFR was also measured using the SI method with samples at 2 and 4 hours (24-GFR) and at 4 and 6 hours (46-GFR), and SS methods according to Groth (4Gr-GFR) and Fleming (4Fl-GFR). Statistical analysis was performed to assess the accuracy, precision, and bias of the methods. RESULTS: Mean 246-GFR was 79.2 ± 21.9 mL/min/1.73 m2. ANOVA indicated a significant difference between 4Gr-GFR and the reference 246-GFR. Bias was lower than 5 mL/min/1.73 m2 for all methods, except for SS methods in subgroups BMI > 40 kg/m2; GFR > 105 or < 45. Precision was adequate and accuracy of 30 % was above 98% for all methods, except for SS methods in subgroup GFR < 45. CONCLUSION: 46-GFR and 246-GFR have high agreement and may be used to evaluate kidney function in patients with solid tumors. Single-sample methods can be adopted in specific situations, for non-obese patients with expected normal GFR.

Postoperative Renal Function in Patients Undergoing Unilateral Nephrectomy: Development of a Prediction Model Using Preoperative Risk Factors and 51Cr-EDTA Clearance.

Objectives: To analyze the preoperative variables associated to the postoperative glomerular filtration rate (GFR) outcomes after nephrectomy for benign and malignant conditions, measured by the reference isotopic technique 51Cr-ethylene diamine tetra-acetic (51Cr-EDTA) and to create a model to predict the short-term postoperative GFR. Secondary aim was to evaluate which of the common equations for GFR estimation (Cockcroft-Gault, Modification of Diet in Renal Disease [MDRD] or Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]) has the best correlation with the 51Cr-EDTA. Methods: Patients undergoing unilateral nephrectomy from 2014 to 2018 were selected. Pre- and postoperative variables were prospectively collected. Univariate and multivariate analyses were done to identify independent risk factors associated with renal function outcomes and to create a model to predict the postoperative GFR. Correlation analyses were performed to evaluate the performance of various serum creatinine-based equations for GFR estimation compared with 51Cr-EDTA. Results: In total, 107 patients were evaluated. After univariate and multivariate analyses, older age (p = 0.008), higher split function of the operated kidney on dimercaptosuccinic acid (DMSA) scintigraphy (p < 0.001), and lower preoperative 51Cr-EDTA (p < 0.001) were independent risk factors for higher GFR decline. Correlation analyses showed that GFR estimated by CKD-EPI equation had the best concordance to GFR measured by 51Cr-EDTA. Conclusions: Based on our findings age, DMSA and lower preoperative 51Cr-EDTA are predictors of postoperative renal function after unilateral nephrectomy. For the assessment of estimated GFR, CKD-EPI equation appears to have the best concordance with 51Cr-EDTA.

Intestinal permeability in strongyloidiasis

The objective of the present study was to assess intestinal permeability in patients with infection caused by Strongyloides stercoralis. Twenty-six patients (16 women and 10 men), mean age 45.9, with a diagnosis of strongyloidiasis were evaluated. For comparison, 25 healthy volunteers (18 women and 7 men), mean age 44.9, without digestive disorders or intestinal parasites served as normal controls. Intestinal permeability was measured on the basis of urinary radioactivity levels during the 24 h following oral administration of chromium-labeled ethylenediaminetetraacetic acid (51Cr-EDTA) expressed as percentage of the ingested dose. The urinary excretion of 51Cr-EDTA was significantly reduced in patients with strongyloidiasis compared to controls (1.60 + or - 0.74 and 3.10 + or - 1.40, respectively, P = 0.0001). Intestinal permeability is diminished in strongyloidiasis. Abnormalities in mucus secretion and intestinal motility and loss of macromolecules could explain the impaired intestinal permeability

Autonomic dysfunction and urinary albumin excretion rate are associated with an abnormal blood pressure pattern in normotensive normoalbuminuric type 1 diabetic patients.

OBJECTIVE: To analyze the role of autonomic function and other possible factors associated with a blunted fall in nocturnal blood pressure. RESEARCH DESIGN AND METHODS: A total of 39 normotensive normnoalbuminuric type 1 diabetic patients were studied. Glomerular filtration rate (51Cr-EDTA technique), extracellular volume (51Cr-EDTA distribution volume), and urinary albumin excretion rate (UAER) (by radioimmunoassay) were measured. The subjects' 24-h ambulatory blood pressure and a 24-h electrocardiogram were recorded simultaneously Heart rate variability was calculated in the time domain for 24 h, in the frequency domain at night, at rest in the supine position, and during tilt. Patients were classified according to diastolic blood pressure (dBP) night/day ratio as dipper patients (< or =0.9) and nondipper patients (>0.9). RESULTS: Nondipper patients presented a higher low-frequency (LF) component (a sympathetic index) and higher LF/high-frequency (HF) ratio during sleep than dipper patients (0.29 +/- 0.12 vs. 0.19 +/- 0.10 normalized units [n.u.], P = 0.008; and 0.98 +/- 0.53 vs. 0.55 +/- 0.45 n.u., P = 0.007, respectively). At rest, the LF component in nondipper patients (0.38 +/- 0.13 n.u.) was higher than in dipper patients (0.27 +/- 0.12 n.u., P = 0.04). After the tilt, nondipper patients did not show an increase in the LF component (P = 0.32), but in dipper patients, the increase was significant (P = 0.001). In both groups, tilting promoted a decrease in the HF component (a parasympathetic index). In a stepwise multiple linear regression analysis, the LF component during sleep and the UAER accounted for 24% of the variability in the dBP night/day ratio. CONCLUSIONS: The predominance of sympathetic activity and increased levels of UAER, although within the normal range, are associated with a blunted fall in nocturnal dBP in normoalbuminuric normotensive type 1 diabetic patients.

Absorçäo de líquido de irrigaçäo na ressecçäo transuretral da próstata em cäes / Irrigating fluid absorption during transurethral resection of the prostate in dogs

Trinta e dois cäes submetidos a entubaçäo do ducto torácico e cateterismo bilateral dos ureteres, foram divididos em 3 grupos: A- 4 cäes inoculados com RISA 131 I ou EDTA 51 Cr por via intravenosa ou peri-prostática; B- controle de 8 cäes submetidos a irrigaçäo vesical e prostática com 8 litros de glicina a 1,2 por cento contendo os marcadores radioativos; C- 8 cäes manejados como em B mas sujeitos à RTU da próstata. Os cäes foram acompanhados por 5 horas. A absorçäo de líquido de irrigaçäo foi calculada pelos métodos volumétrico e radioisotópico. Em 5 horas, 97 por cento da RISA 131 I inoculada via intravenosa permanecia neste espaço enquanto apenas 4,6 por cento da injetada no espaço peri-prostático penetrou no compartimento vascular. Para o EDTA 51 Cr, 63,6 por cento da massa inoculada no espaço peri-prostático foi recuperada na urina após 5 horas. O método volumétrico mostrou absorçäo média de 22,7 ml no grupo B e 276 ml no C, e o radioisotópico de 6,3 ml e 165,4 ml, respectivamente. O modelo experimental tem similaridades com o ser humano

Aumento da permeabilidade intestinal ao 51Cr-EDTA em crianças com diarréia persistente / Increased intestinal permeability to 51Cr-EDTA among children with persistent diarrhea

A diarréia persistente, uma condiçäo altamente prevalente em países em desenvolvimento, ocasiona diferentes alteraçöes morfológicas e funcionais na mucosa do intestino delgado, incluindo aumento da permeabilidade a diversas moléculas de prova. Investiga-se, pela primeira vez, a permeabilidade intestinal ao Cr-EDTA em crianças brasileiras com diarréia persistente. O teste de absorçäo do Cr-EDTA foi realizado em 13 crianças controle e em 14 com diarréia persistente, oferecendo-se 50 µCi da substância teste, por via oral, com posterior detecçäo da radioatividade excretada na urina de 24 horas. Houve diferença estatisticamente significante entre o grupo controle (mediana = 1,26 variaçäo = 0,20-3,31 por cento) e com diarréia persistente (mediana = 4,68; variaçäo = 1,40-10,29 por cento). Estabelecendo como padräo de referência de normalidade para o teste de absorçäo urinária de Cr-EDTA os valores mínimo e máximo encontrados no grupo controle, observaram-se que 61,5 por cento dos pacientes com diarréia persistente apresentaram resultado alterados. Nos pacientes com diarréia persistente, a excreçäo do Cr-EDTA foi significativamente maior no grupo que fez uso de dieta à base de hidrolisado protéico e/ou nutriçäo parenteral total, em comparaçäo com o que näo fez, demonstrando sua possível utilidade como indicador de gravidade. Em quatro pacientes com diarréia persistente, o teste foi realizado após a recuperaçäo clínica, sendo que houve queda nos valores de excreçäo em todos os casos. A partir destes dados, pode-se concluir que: 1) na diarréia persistente deve haver alteraçäo na permeabilidade intestinal, que permitiria a entrada aumentada de antígenos alimentares locais, com subseqüente sensibilizaçäo e enteropatia alérgica, contribuindo para a perpetuaçäo do ciclo de diarréia, má absorçäo e desnutriçäo; 2) o teste do Cr-EDTA pode ser útil como indicador de gravidade na diarréia persistente; 3) a alteraçäo da permeabilidade intestinal é um fenômeno secundário na diarréia persistente e, com a reconstruçäo da barreira intestinal, ocorre normalizaçäo da mesma.

[Increased intestinal permeability to 51 Cr-EDTA among children with persistent diarrhea]. / Aumento da permeabilidade intestinal ao 51Cr-EDTA em crianças com diarréia persistente.

Persistent diarrhea, a condition highly prevalent in developing countries, causes different morphological and functional alterations of the mucosa of the small intestine, including increased permeability to different test molecules. In the present study we investigate for the first time the intestinal permeability to 51Cr-EDTA of Brazilian children with persistent diarrhea. The test of 51Cr-EDTA absorption was performed in 13 control children and in 14 children with persistent diarrhea by offering 50 microCi of the test substance by the oral route, with later detection of radioactivity excreted in 24-hour urine. There was a statistically significant difference between the control group (median = 1.26; range = 0.20-3.31%) and the group with persistent diarrhea (median = 4.68; range = 1.40-10.29%). Using the minimum and maximum values detected in the control group as the normal reference standard for the test of urinary 51Cr-EDTA absorption, we observed that 61.5% of the patients with persistent diarrhea showed altered results. Among the patients with persistent diarrhea, 51Cr-EDTA excretion was significantly higher in the group fed a protein hydrolysate diet and/or total parenteral nutrition than in the group that did not receive this diet. In four patients with persistent diarrhea, the test was performed after clinical recovery, with a fall in the excretion levels in all cases. On the basis of these data, we may conclude that: 1) in persistent diarrhea there must be alteration of intestinal permeability that might permit an increased entry of local alimentary antigens, with subsequent sensitization and allergic enteropathy, contributing to the perpetuation of the diarrhea, malabsorption and malnutrition cycle; 2) the 51Cr-EDTA test may be useful as an indicator of severity in persistent diarrhea; 3) alteration of intestinal permeability is a secondary phenomenon in persistent diarrhea, with normalization occurring after reconstruction of the intestinal barrier.

Impairment of the murine mononuclear phagocyte system function by antigenic stimulation.

This study examined the mononuclear phagocyte system (MPS) capacity to eliminate IgG-sensitized syngeneic erythrocytes (EA) after antigenic challenge. Survival data of EA in normal and preimmunized mice showed that a single dose of T-dependent antigen was able to delay Fc gamma R-dependent clearance. This impairment in EA elimination was dependent on the dose of antigen injected. On the other hand, T-independent antigens, B cell mitogen, and the inflammatory agent Freund's incomplete adjuvant were ineffective in modulating MPS function. As expected, the liver and the spleen were the main sites of EA trapping, but the spleen of immunized mice sequestered significantly less EA than that of control mice. Impaired clearance capacity was observed as soon as 24 hr after immunization and was persistent up to the seventh day after antigenic stimulation. Moreover, mice decomplementation by cobra venom factor treatment did not prevent the impairment of MPS by antigenic stimulation, suggesting that it is strictly Fc gamma R dependent. Our results indicate that stimulation of the immune system by T-dependent antigens can diminish the Fc gamma R-mediated clearance capacity of the MPS. The possible mechanisms involved in this regulation are discussed.