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Sample records for 51cr-edta clearance method

  1. Determination of optimal sampling times for a two blood sample clearance method using (51)Cr-EDTA in cats.

    Vandermeulen, Eva; De Sadeleer, Carlos; Piepsz, Amy; Ham, Hamphrey R; Dobbeleir, André A; Vermeire, Simon T; Van Hoek, Ingrid M; Daminet, Sylvie; Slegers, Guido; Peremans, Kathelijne Y

    2010-08-01

    Estimation of the glomerular filtration rate (GFR) is a useful tool in the evaluation of kidney function in feline medicine. GFR can be determined by measuring the rate of tracer disappearance from the blood, and although these measurements are generally performed by multi-sampling techniques, simplified methods are more convenient in clinical practice. The optimal times for a simplified sampling strategy with two blood samples (2BS) for GFR measurement in cats using plasma (51)chromium ethylene diamine tetra-acetic acid ((51)Cr-EDTA) clearance were investigated. After intravenous administration of (51)Cr-EDTA, seven blood samples were obtained in 46 cats (19 euthyroid and 27 hyperthyroid cats, none with previously diagnosed chronic kidney disease (CKD)). The plasma clearance was then calculated from the seven point blood kinetics (7BS) and used for comparison to define the optimal sampling strategy by correlating different pairs of time points to the reference method. Mean GFR estimation for the reference method was 3.7+/-2.5 ml/min/kg (mean+/-standard deviation (SD)). Several pairs of sampling times were highly correlated with this reference method (r(2) > or = 0.980), with the best results when the first sample was taken 30 min after tracer injection and the second sample between 198 and 222 min after injection; or with the first sample at 36 min and the second at 234 or 240 min (r(2) for both combinations=0.984). Because of the similarity of GFR values obtained with the 2BS method in comparison to the values obtained with the 7BS reference method, the simplified method may offer an alternative for GFR estimation. Although a wide range of GFR values was found in the included group of cats, the applicability should be confirmed in cats suspected of renal disease and with confirmed CKD. Furthermore, although no indications of age-related effect were found in this study, a possible influence of age should be included in future studies. PMID:20452793

  2. 51Cr-EDTA plasma clearance in severe renal failure determined by one plasma sample

    Kamper, A L; Nielsen, S L

    1989-01-01

    sample clearance' formulas disregarding exact time of plasma sampling. This method might provide values 3.1 ml/min below or 2.9 ml/min above the established method of total 51Cr-EDTA plasma clearance, and would thus provide insufficient agreement. In the other method an estimate of plasma activity at......Two hundred and thirty-four measurements of standard 51Cr-EDTA plasma clearance were made in 50 patients with severe chronic renal failure. Based on these data two calculation methods were attempted using one plasma sample drawn 24 h after injection of 51Cr-EDTA. One of the methods used the 'one...... zero-time was derived from injected dose and body surface area. This method might provide values 1.5 ml/min below or 0.8 ml/min above the established method of 51Cr-EDTA plasma clearance, which would be acceptable for clinical purposes. It is concluded that exact plasma clearance of 51Cr-EDTA in severe...

  3. Conventional measurements of GFR using 51Cr-EDTA overestimate true renal clearance by 10 percent

    It is widely believed that measurement of the area under the plasma clearance curve (AUC) following a single intravenous injection of chromium-51 labelled ethylene diamine tetra-acetic acid (51Cr-EDTA) is a gold standard method for determining glomerular filtration rate (GFR). However, there are reports that 51Cr-EDTA may have a significant extrarenal clearance. The aim of this study was to identify the non-renal component of 51Cr-EDTA plasma clearance contributing to the AUC measurement of GFR. Seventy healthy postmenopausal women (mean age 60 years, range 45-79 years) were injected with 3 MBq 51Cr-EDTA and 0.25 MBq iodine-125 labelled human serum albumin and 11 blood samples taken between 0 and 4 h through an indwelling venous cannula. For the first 21 subjects, two complete urine collections were made 0-2 h and 2-4 h after injection, and for the final 49 patients, four 1-h urine collections were made. The mean 51Cr-EDTA total plasma clearance was 84 ml/min (range 50-132 ml/min). The mean ratio (SEM) of urine to total clearance determined from the cumulative 1-, 2-, 3- and 4-h data was 0.903 (0.018), 0.891 (0.013), 0.898 (0.011) and 0.899 (0.010) respectively and remained constant despite the mean urine concentration decreasing from 122% to 15%/litre during this period. A least squares fit to data from the 238 individual urine collections was used to determine the fraction of the total plasma clearance attributable to renal clearance, α0, and the residual urine volume, ΔV. The results were α0=0.910 (95% CI: 0.889-0.932) and ΔV=14 ml (95% CI: -4 to +34 ml). The overestimation of the true renal clearance of 51Cr-EDTA by the AUC method is believed to be due to the failure of the plasma clearance curve to reach the true terminal exponential by 2 h after injection as usually assumed. As a result, conventional measurements of GFR using 51Cr-EDTA overestimate the true renal clearance of tracer by approximately 10%. (orig.)

  4. Total plasma clearance versus urinary plasma clearance of (51)Cr-EDTA in patients with cirrhosis with and without fluid retention

    Henriksen, Ulrik Lütken; Hansen, Hanne B; Ring-Larsen, Helmer;

    2015-01-01

    Abstract Background and aim. In patients with fluid retention, the total plasma clearance of (51)Cr-EDTA (ClP) may overestimate the glomerular filtration rate (GFR). The present study was therefore undertaken in order to compare ClP with the urinary plasma clearance of (51)Cr-EDTA (ClU) in patients...... with cirrhosis with and without fluid retention. Material and methods. A total of 136 patients with cirrhosis (24 without fluid retention, 112 with ascites) received a quantitative intravenous injection of (51)Cr-EDTA followed by plasma and quantitative urinary samples for 5 hours. ClP was determined...... from the injected dose relative to the plasma concentration-time area, extrapolated to infinity. ClU was determined as urinary excretion relative to the plasma concentration-time area up to voiding. Results. In patients without fluid retention, the difference between ClP and ClU (ClP - ClU = ClΔ) was...

  5. Comparison of 51Cr-EDTA- with 99mTc-DTPA-slope-clearance for estimation of glomerular filtration rate using the one-compartment model

    Aim of this study is to determine the relationship between 51Cr-EDTA and 99mTc-DTPA slope clearance applying the 'one-compartment model'. Methods: The 'one-compartment model' was chosen to calculate and to compare the glomerular filtration rates of 25 patients with normal and pathological creatinin values after injection of 51Cr-EDTA and 99mTc-DTPA simultaneously. Results: The two clearance values correlated well (r=0.996), and the 99mTc-DTPA clearance was systematically higher (28%). The 99mTc-DTPA was calculated and compared after taking three plasma samples. Taking two samples, only minor differences were seen and the correlation was high (r=0.992). Conclusion: The results of this study encouraged us to adopt the use of 99mTc-DTPA instead of 51Cr-EDTA in determining the glomerular filtration applying the 'one-compartment model' in slope with two plasma samples. (orig.)

  6. Comparative study of conventional PAH and inulin clearance and slope clearance of 131I-o-hippuric acid and 51Cr-EDTA

    ''Classic'' PAH and inulin clearance were determined in 81 patients with renal anomalies or renal diseases of different genesis and severity. In addition, radioisotope nephrography was carried out after administration of I-131-o-hippuric acid, followed by administration of Cr-51-EDTA. The activity decrease was recorded by a sensor located over the patient's right shoulder; the activities of a serum sample and of the urine excreted after 21 or 31 min were measured, and the findings were compared with those of the classic method. The clearance data calculated on the basis of the soulder measurements were hardly compatible with those of the conventional method in the case of 131I-o-hippuric acid (r=0.54) and totally incompatible in the case of 51Cr-EDTA. This means that the method described by Oberhausen is the only accurate method available for a quantitative assessment of the renal function on the basis of measurements of the activity decrease in the body. The activity of urine excreted after 31 min (131I-hippuric acid:r=0.992, 51Cr-EDTA:r=0.79) is a sufficiently accurate parameter although it is inaccurate at PAH clearance, values > 130 ml/min and inulin clearance values > 30 ml/min. Of the many parameters of radioisotope nephrogram curves, in the case of 131I-o-hippuric acid only the parameters related to the ascent between 48 and 120 sec or to the secant ascent yield sufficient quantitative information for certain functional regions (r=0.9 resp. r=0.93). In the case of 51Cr-EDTA, semiquantitative information on the renal function can be obtained by constructing secants on the nephrogram curves (r=0.7 resp. r=0.72). Here as in the case of 131I-hippuric acid, the contribution of each kidney can be determined individually from the functional analysis of both kidneys. (orig.)

  7. What method to use for the renal clearance with {sup 51}Cr-E.D.T.A.: retrospective study among 1157 adults and 286 children; Quelle methode de mesure utiliser pour la clairance renale au 51Cr-EDTA: etude retrospective chez 1157 adultes et 286 enfants

    Lacoeuille, F.; Machefert, N.; Vervueren, L.; Berthelot, C.; Rakotonirina, H.; Le Jeune, J.J.; Couturier, O. [CHU d' Angers, Service de medecine nucleaire, 49 (France); Drablier, G.; Cahouet-Vannier, A. [CHU d' Angers, Service de pharmacie, 49 (France); Denizot, B. [CH Annemasse, service de medecine nucleaire, 74 (France)

    2010-07-01

    Purpose: in the objective to make our practices evolve and to limit the numbers of sampling for patients, we searched to determine if the methods used (4,2 or 1 sampling) to measure the renal clearance to {sup 51}Cr-EDTA give results comparable on the population of patients concerned by this examination. Conclusions: This study allowed to enlighten interchangeability between the four points and two points method for the population studied. It allows to consider a change in our practice for the profit of a two points methods. (N.C.)

  8. Gamma-variate plasma clearance versus urinary plasma clearance of (51) Cr-EDTA in patients with cirrhosis with and without fluid retention

    Fuglsang, Stefan; Henriksen, Ulrik L; Hansen, Hanne B;

    2016-01-01

    In patients with fluid retention, the plasma clearance of (51) Cr-EDTA (Clexp obtained by multiexponential fit) may overestimate the glomerular filtration rate (GFR). The present study was undertaken to compare a gamma-variate plasma clearance (Clgv) with the urinary plasma clearance of (51) Cr......-EDTA (Clu ) in patients with cirrhosis with and without fluid retention. A total of 81 patients with cirrhosis (22 without fluid retention, 59 with ascites) received a quantitative intravenous injection of (51) Cr-EDTA followed by plasma and quantitative urinary samples for 5 h. Clgv was determined from the...... injected dose relative to the plasma concentration-time area, obtained by a gamma-variate iterative fit. Clexp and Clu were determined by standard technique. In patients without fluid retention, Clgv , Clexp and Clu were closely similar. The difference between Clgv and Clu (Clgv - Clu = ΔCl) was mean -0...

  9. Over-estimation of glomerular filtration rate by single injection [51Cr]EDTA plasma clearance determination in patients with ascites

    Henriksen, Jens Henrik Sahl; Brøchner-Mortensen, J; Malchow-Møller, A; Schlichting, P

    1980-01-01

    The total plasma (Clt) and the renal plasma (Clr) clearances of [51Cr]EDTA were determined simultaneously in nine patients with ascites due to liver cirrhosis. Clt (mean 78 ml/min, range 34-115 ml/min) was significantly higher than Clr (mean 52 ml/min, range 13-96 ml/min, P < 0.005). The ascitic...... fluid-plasma activity ratio of [51Cr]EDTA increased throughout the investigation period (5h). The results suggest that [51Cr]EDTA equilibrates slowly with the peritoneal space which indicates that Clt will over-estimate the glomerular filtration rate by approximately 20 ml/min in patients with ascites...

  10. Evaluation of renal function in rats: Renal clearance of 99mTc-DTPA underestimates glomerular filtration rate (GFR) as compared with renal clearance of eH-inulin or 51 CR-EDTA

    The rat is the most commonly used experimental animal and frequently being used to examine the pathophysiology in renal disease. Thus, it is important to apply techniques where renal function is assessed accurately. A special challenge exists in chronic unilateral renal disease for accurate measurement of single kidney GFR (SKGFR). We therefore examined the possibility of developing a method where SK GFR is measured in rats from the plasma clearance of 99mTc-DTPA and the reno graphically determined renal split function. A detailed comparison of renal clearance (Clr) and plasma clearance (Clp) of 99mTc-DTPA with that of 51-Cr-EDTA and 3H-inulin was performed in conscious rats with permanent catheters in the carotic artery, jugular vein and the urinary bladder using the following protocols: 1) Comparison of Clr of 99mTc-DTPA with 3H-inulin using a constant infusion clearance technique with four periods (P1-P4)(n=11), 2) comparison of Clr of 99m Tc-DTPA with that of 51Cr-EDTA or 3H-inulin (n=8) 3) comparison of Clr of 51Cr-EDTA and 3H-inulin using a constant infusion clearance technique with Clp of 99mTc-DTPA using a single injection technique with plasma sampling 4 hours after injection (n=11) and 4) comparison of Clp of 51Cr-EDTA with 99mTc-DTPA using the single injection technique (n=5). The results surprisingly showed that Clr of 99mTc-DTPA consistently was significantly lower than Clr of 51Cr-EDTA (548±146 vs. 860±49 □1/min/100g (avg±std);p<0.01) and of 3H-inulin (548±146 vs. 975±135 □1/min/100g; p<0.01: Interestingly, Clr of 99mTc-DTPA was progressively reduced with time in contrast to a constant Clr of inulin (P1:693±108 vs 939±118; P2:591±94 vs 877±17, P3:594±74 vs 947±131; P4:569±78 vs 991±122). Furthermore, Clp of 99mTc-DTPA was significantly lower than Clp of 51Cr-EDTA (874±130 vs. 1092±43 □1/min/100g;p<(0.01). The average clearance ratio DTPA/EDTA using constant infusion was 0.65±0.15 and 0.80±0.15 after single injection. In

  11. Glomerular filtration rate measured by 51Cr-EDTA clearance: evaluation of captopril-induced changes in hypertensive patients with and without renal artery stenosis

    Anna Alice Rolim Chaves

    2010-01-01

    Full Text Available INTRODUCTION: Renal artery stenosis can lead to renovascular hypertension; however, the detection of stenosis alone does not guarantee the presence of renovascular hypertension. Renovascular hypertension depends on activation of the renin-angiotensin system, which can be detected by functional tests such as captopril renal scintigraphy. A method that allows direct measurement of the baseline and post-captopril glomerular filtration rate using chromium-51 labeled ethylenediamine tetraacetic acid (51Cr-EDTA could add valuable information to the investigation of hypertensive patients with renal artery stenosis. The purposes of this study were to create a protocol to measure the baseline and post-captopril glomerular filtration rate using 51Cr-EDTA, and to verify whether changes in the glomerular filtration rate permit differentiation between hypertensive patients with and without renal artery stenosis. METHODS: This prospective study included 41 consecutive patients with poorly controlled severe hypertension. All patients had undergone a radiological investigation of renal artery stenosis within the month prior to their inclusion. The patients were divided into two groups: patients with (n=21 and without renal artery stenosis, (n=20. In vitro glomerular filtration rate analysis (51Cr-EDTA and 99mTc-DMSA scintigraphy were performed before and after captopril administration in all patients. RESULTS: The mean baseline glomerular filtration rate was 48.6±21.8 ml/kg/1.73 m² in the group wuth renal artery stenosis, which was significantly lower than the GFR of 65.1±28.7 ml/kg/1.73m² in the group without renal artery stenosis (p=0.04. Captopril induced a significant reduction of the glomerular filtration rate in the group with renal artery stenosis (to 32.6±14.8 ml/kg/1.73m², p=0.001 and an insignificant change in the group without RAS (to 62.2±23.6 ml/kg/1.73m², p=0.68. Scintigraphy with technetium-99m dimercapto-succinic acid (DMSA did not show

  12. Glomerular filtration rate measured by {sup 51}Cr-EDTA clearance: evaluation of captopril-induced changes in hypertensive patients with and without renal artery stenosis

    Chaves, Anna Alice Rolim; Buchpiguel, Carlos Alberto; Praxedes, Jose Nery; Bortolotto, Luiz Aparecido; Sapienza, Marcelo Tatit, E-mail: annaalice100@yahoo.com.b [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina. Dept. de Neurologia

    2010-07-01

    Introduction: renal artery stenosis can lead to renovascular hypertension; however, the detection of stenosis alone does not guarantee the presence of renovascular hypertension. Renovascular hypertension depends on activation of the renin-angiotensin system, which can be detected by functional tests such as captopril renal scintigraphy. A method that allows direct measurement of the baseline and post-captopril glomerular filtration rate using chromium-51 labeled ethylenediamine tetraacetic acid ({sup 51}Cr-EDTA) could add valuable information to the investigation of hypertensive patients with renal artery stenosis. The purposes of this study were to create a protocol to measure the baseline and post-captopril glomerular filtration rate using {sup 51}Cr-EDTA, and to verify whether changes in the glomerular filtration rate permit differentiation between hypertensive patients with and without renal artery stenosis. Methods: this prospective study included 41 consecutive patients with poorly controlled severe hypertension. All patients had undergone a radiological investigation of renal artery stenosis within the month prior to their inclusion. The patients were divided into two groups: patients with (n=21) and without renal artery stenosis, (n=20). In vitro glomerular filtration rate analysis ({sup 51}Cr-EDTA) and {sup 99m}Tc-DMSA scintigraphy were performed before and after captopril administration in all patients. Results: the mean baseline glomerular filtration rate was 48.6+-21.8 ml/kg/1.73 m{sup 2} in the group with renal artery stenosis, which was significantly lower than the GFR of 65.1+-28.7 ml/kg/1.73m{sup 2} in the group without renal artery stenosis (p=0.04). Captopril induced a significant reduction of the glomerular filtration rate in the group with renal artery stenosis (to 32.6+-14.8 ml/kg/1.73m{sup 2}, p=0.001) and an insignificant change in the group without RAS (to 62.2+-23.6 ml/kg/1.73m{sup 2}, p=0.68). Scintigraphy with technetium-99m dimercapto

  13. Validation of calculated eGFR compared with 51Cr-EDTA clearance on a patient population from northern Jutland in Denmark

    Nielsen, Nikolaj Schandorph

    I mange år har man anvendt patienters plasma-creatinin niveau i blodet som et estimat for nyrefunktionen. I september 2010 blev der i Aalborg indført eGFR som etstimat på nyrefunktion ud fra plasma-creatinin. Det er kendt at GFR bestemt ved 51Cr-EDTA clearence er det bedste bud på patienters...... nyrefunktion, og derfor undersøges validiteten af eGFR i forhold til GFR bestemt ved 51Cr-EDTA clearence....

  14. Effect of background region of interest and time-interval selection on glomerular filtration ratio estimation by percentage dose uptake of (99m)Tc-DTPA in comparison with (51)Cr-EDTA clearance in healthy cats.

    Debruyn, Katrien; Vandermeulen, Eva; Saunders, Jimmy H; Dobbeleir, André A; Ham, Hamphrey R; Peremans, Kathelijne

    2013-08-01

    Evaluation of glomerular function is a useful part of the diagnostic approach in animals suspected of having renal disease. Time-interval and background region of interest (bg ROI) selection are determining factors when calculating the glomerular filtration ratio (GFR) based on percentage uptake of (99m)technetium-labelled diethylene triamine penta-acetic acid ((99m)Tc-DTPA). Therefore, three different time intervals (60-120 s, 120-180 s, 60-180 s) and three different bg ROIs (C-shape, caudolateral, cranial + caudal) were investigated. In addition, global GFRs based on percentage dose uptake of (99m)Tc-DTPA for the different time-intervals and bg ROIs were compared with the global GFR based on (51)chromium-ethylene diaminic tetra-acetic acid ((51)Cr-EDTA) plasma clearance in nine healthy European domestic shorthair cats. Paired Student's t-tests and linear regression analysis were used to analyse the data. Different time intervals seemed to cause significant variation (P <0.01) in absolute GFR values, regardless of the choice of bg ROI. Significant differences (P <0.01) between bg ROIs were only observed in the 120-180s time interval between the C-shape and cranial + caudal bg ROI, and between the caudolateral and cranial + caudal bg ROI. The caudolateral bg ROI in the 60-180 s time interval showed the highest correlation coefficient (r = 0.882) between (99m)Tc-DTPA and (51)Cr-EDTA, although a significant difference (P <0.05) was present between both techniques. PMID:23349527

  15. 51Cr-EDTA: a marker of early intestinal rejection in the rat

    Intestinal permeability was studied after accessory intestinal transplantation in Lewis rats. Five groups were evaluated: Group 1--isografts (N = 6); Group 2--Lewis X Brown Norway F1 (LBN-F1) allografts (N = 6); Group 3--isografts treated with CsA 2 mg/kg/day X 10 days (N = 6); Group 4--LBN-F1 allografts treated with CsA 2 mg/kg/day X 10 days (N = 6); Group 5--LBN-F1 allografts treated with CsA 4 mg/kg/day X 28 days (N = 6). Chromium-labeled ethylenedimianetetraacetate (51Cr-EDTA) was given through the proximal stoma of the graft. Renal clearance of 51Cr-EDTA and mucosal biopsies were followed post-transplant. The biopsies of the intestinal graft showed no rejection in Groups 1, 3, and 5; fulminant rejection in Group 2; and mild atypical rejection in Group 4. 51Cr-EDTA clearance was elevated in all groups during the first 7 days post-transplant. Thereafter, 51Cr-EDTA excretion fell to lower levels in the animals with histologically normal grafts (Groups 1, 3, and 5). 51Cr-EDTA excretion in Group 4 was increased with the first histological evidence of rejection on Day 14 and remained elevated until sacrifice (P less than 0.02 compared to Groups 3 and 5). A transient permeability defect occurs after intestinal grafting. Once the graft has recovered from this injury, 51Cr-EDTA is a sensitive marker for intestinal rejection

  16. Estimating GFR in children with 99mTc-DTPA renography: a comparison with single-sample 51Cr-EDTA clearance

    Gutte, Henrik; Møller, Michael L; Pfeifer, Andreas K; Thorup, Jørgen Mogens; Borgwardt, Line; Borgwardt, Lise; Kristoffersen, Ulrik S; Kjaer, Andreas

    2010-01-01

    Glomerular filtration rate (GFR) measurement by (51)Cr-ethylenediaminetetraacetic acid (EDTA) and blood sampling in children is usually cumbersome for the patient, parents and laboratory technicians. We have previously developed a method accurately estimating GFR in adults. The aim of the present...

  17. Intestinal permeability assessed by 51Cr-EDTA in rats with CCl4 - induced cirrhosis Permeabilidade intestinal ao 51-Cr-EDTA em ratos com cirrose induzida por CCl4

    Ana Regina L. Ramos

    2010-06-01

    Full Text Available CONTEXT: The straight relationship between cirrhosis and impaired intestinal barrier has not been elucidated yet. OBJECTIVES: To verify 51Cr-EDTA-intestinal permeability in rats with CCl4-induced cirrhosis and controls. METHOD: Fifty male Wistar rats weighing 150-180 g were separated in three groups: 25 animals received CCl4 0.25 mL/kg with olive oil by gavage with 12 g/rat/day food restriction for 10 weeks (CCl4-induced cirrhosis; 12 received the same food restriction for 10 weeks (CCl4-non exposed. Other 13 rats received indomethacin 15 mg/kg by gavage as positive control of intestinal inflammation. RESULTS: The median (25-75 interquartile range 51Cr-EDTA-IP values of cirrhotic and CCl4-non exposed rats were 0.90% (0.63-1.79 and 0.90% (0.60-1.52 respectively, without significant difference (P = 0.65. Animals from indomethacin group showed 51Cr-EDTA-IP, median 7.3% (5.1-14.7, significantly higher than cirrhotic and CCl4-non exposed rats (PCONTEXTO: A relação direta entre cirrose e alterações na barreira intestinal ainda não foi devidamente esclarecida. OBJETIVO: Verificar a permeabilidade intestinal ao 51Cr-EDTA em ratos com cirrose induzida por tetracloreto de carbono (CCl4 e controles. MÉTODO: Cinquenta ratos Wistar machos pesando 150-180 g foram separados em três grupos: 25 animais receberam CCl4 0,25 mL/kg diluído em óleo de oliva por gavagem com restrição dietética de 12 g/rato/dia por 10 semanas (grupo cirrose induzida por CCl4; 12 receberam a mesma restrição dietética por 10 semanas (grupo não exposto ao CCl4. Outros 13 ratos receberam indometacina 15 mg/kg por gavagem como controle positivo de inflamação intestinal. RESULTADOS: A mediana (intervalo interquartil 25-75 dos valores de permeabilidade intestinal ao 51Cr-EDTA dos grupos cirrose induzida por CCl4 e não exposto ao CCl4 foram 0,90% (0,63-1,79 e 0,90% (0,60-1,52, respectivamente, sem significância estatística (P = 0,65. Os animais do grupo indometacina

  18. (51Cr)EDTA intestinal permeability in children with cow's milk intolerance

    Schrander, J.J.; Unsalan-Hooyen, R.W.; Forget, P.P.; Jansen, J. (Academic Hospital Maastricht (Netherlands))

    1990-02-01

    Making use of ({sup 51}Cr)EDTA as a permeability marker, we measured intestinal permeability in a group of 20 children with proven cow's milk intolerance (CMI), a group of 17 children with similar complaints where CMI was excluded (sick controls), and a group of 12 control children. ({sup 51}Cr)EDTA test results (mean +/- SD) were 6.85 +/- 3.64%, 3.42 +/- 0.94%, and 2.61 +/- 0.67% in the group with CMI, the sick control, and the control group, respectively. When compared to both control groups, patients with cow's milk intolerance (CMI) showed a significantly increased small bowel permeability. We conclude that the ({sup 51}Cr)EDTA test can be helpful for the diagnosis of cow's milk intolerance.

  19. [51Cr]EDTA intestinal permeability in children with cow's milk intolerance

    Making use of [51Cr]EDTA as a permeability marker, we measured intestinal permeability in a group of 20 children with proven cow's milk intolerance (CMI), a group of 17 children with similar complaints where CMI was excluded (sick controls), and a group of 12 control children. [51Cr]EDTA test results (mean +/- SD) were 6.85 +/- 3.64%, 3.42 +/- 0.94%, and 2.61 +/- 0.67% in the group with CMI, the sick control, and the control group, respectively. When compared to both control groups, patients with cow's milk intolerance (CMI) showed a significantly increased small bowel permeability. We conclude that the [51Cr]EDTA test can be helpful for the diagnosis of cow's milk intolerance

  20. Intestinal permeability to [51Cr]EDTA in children with cystic fibrosis

    Intestinal permeability was investigated in 14 children with cystic fibrosis making use of [51Cr]EDTA as probe molecule. Ten normal young adults and 11 children served as controls. After oral administration of [51Cr]EDTA, 24 h urine was collected. Urinary radioactivity was calculated and results expressed as percentage of oral dose excreted in 24 h urine. Mean and SEM were as follows: 2.51 +/- 0.21, 2.35 +/- 0.24, and 13.19 +/- 1.72 for control children, normal adults, and cystic fibrosis patients, respectively. The permeability differences between cystic fibrosis patients and either control children or control adults are significant (p less than 0.001)

  1. Reversibility of increased intestinal permeability to 51Cr-EDTA in patients with gastrointestinal inflammatory diseases

    Intestinal permeability in adults with inflammatory gastrointestinal diseases was investigated by measuring the 24-h urinary excretion of orally administered 51Cr-EDTA. Eighty controls along with 100 patients with Crohn's disease, 46 patients with ulcerative colitis, 20 patients with gluten-sensitive enteropathy, and 18 patients with other diseases were studied. In controls, the median 24-h excretion was 1.34%/24 h of the oral dose. Patients with Crohn's disease (median 2.96%/24 h), ulcerative colitis (median 2.12%/24 h), and untreated gluten-sensitive enteropathy (median 3.56%/24 h) had significantly elevated urinary excretion of the probe compared to controls (p less than 0.0001). Increased 24-h urinary excretion of 51Cr-EDTA had a high association with intestinal inflammation (p less than 0.0001). Test specificity and sensitivity were 96% and 57%, respectively. A positive test has a 96% probability of correctly diagnosing the presence of intestinal inflammation, whereas a negative test has a 50% probability of predicting the absence of disease

  2. Intestinal permeability to (/sup 51/Cr)EDTA in children with Crohn's disease and celiac disease

    Turck, D.; Ythier, H.; Maquet, E.; Deveaux, M.; Marchandise, X.; Farriaux, J.P.; Fontaine, G.

    1987-07-01

    (/sup 51/Cr)EDTA was used as a probe molecule to assess intestinal permeability in 7 healthy control adults, 11 control children, 17 children with Crohn's disease, and 6 children with untreated celiac disease. After subjects fasted overnight, 75 kBq/kg (= 2 microCi/kg) /sup 51/Cr-labeled EDTA was given by mouth; 24-h urinary excretion of (/sup 51/Cr)EDTA was measured and expressed as a percentage of the total oral dose. Mean and SD were as follows: control adults 1.47 +/- 0.62, control children 1.59 +/- 0.55, and patients with Crohn's disease or celiac disease 5.35 +/- 1.94. The difference between control children and patients was statistically significant (p less than 0.001). These results show that intestinal permeability to (/sup 51/Cr)EDTA is increased among children with active or inactive Crohn's disease affecting small bowel only or small bowel and colon, and with untreated celiac disease. The (/sup 51/Cr)EDTA permeability test could facilitate the decision to perform more extensive investigations in children suspected of small bowel disease who have atypical or poor clinical and biological symptomatology.

  3. Arterio-venous concentration difference of [51Cr]EDTA after a single injection in man. Significance of renal function and local blood flow

    Rehling, M; Hyldstrup, L; Henriksen, Jens Henrik Sahl

    1989-01-01

    The present investigation was undertaken in order to study (1) the difference in arterial (Ca) and venous (Cv) concentration of [51Cr]EDTA (ethylenediaminetetraacetate) after a single intravenous injection, (2) the impact of different physiological variables on this difference, and (3) the error...

  4. Reassessment of a classical single injection 51Cr-EDTA clearance method for determination of renal function in children and adults. Part I: Analytically correct relationship between total and one-pool clearance

    Jødal, Lars; Brøchner-Mortensen, Jens

    2009-01-01

    and adults. Material and methods. Cl was determined in 149 subjects (M/F/children: 71/46/32) from a complete plasma concentration curve followed for 4-5 h after injection of 51Cr-EDTA (range of clearance: 8-183 mL/min/1.73 m²). Plasma volume, PV and the "missing" area under the plasma fraction curve......Background. Total plasma clearance of 51Cr-EDTA, Cl, is widely used as a measure of GFR. Commonly, only the final part of the plasma concentration curve is measured, and a one-pool clearance (slope-intercept clearance), Cl1, is computed. Empirically determined second-order polynomials of the......, a (minutes), not used for determination of Cl1, were measured. Results. The true relationship between Cl and Cl1 is given by Cl = Cl1/(1+f·Cl1), where f = a/PV. For men, women and children alike, the equation f = 0.0032·BSA-1.3 was applicable (BSA = body surface area in m²). Estimation errors on...

  5. Excretion of radionuclides in human breast milk following administration of 125I-fibrinogen, 99Tc/sup m/-MAA and 51Cr-EDTA

    Very few biokinetic and dosimetric data for estimating the absorbed dose to a breast-feeding child are available in the literature. The few available are usually case reports. We have measured the activity concentration in breast milk from one patient after administration of 125I-fibrinogen, from two patients after administration of 99Tc/sup m/-macroaggregated albumin, and from one patient after administration of 51Cr-EDTA. We have compared our data with earlier published results and estimated the absorbed dose to the breast-feeding child using biokinetic data presented in this work and recently published S-values for new-born children

  6. Mean retention time of 51Cr-EDTA and 103Ru-phenanthroline in the digestive tract of sheep and bulls after feeding on straw pellets

    Two lots of straw pellets (supplemented with 10% molasses), produced either with a 5 mm sieve in a hammer mill (lot A) or with a 12 mm sieve (lot B) from wheat straw, were tested with 4 sheep (wethers, average live weight 43 kg) and 4 bulls (average live weight 170 kg). After carrying out a digestibility experiment, the mean retention time, the 80% excretion of the markers and the transit time were ascertained with the help of 51Cr-EDTA and 103Ru-phenanthroline. The digestibility of carbohydrates (both crude fiber and N-free extractives) was significantly higher for the bulls than for the sheep. (author)

  7. Rapid decline in 51Cr-EDTA measured renal function during the first weeks following lung transplantation

    Hornum, M.; Iversen, M.; Steffensen, I.;

    2009-01-01

    We previously described a 54% decline in renal function at 6 months after lung transplantation (LTx). We hypothesized that this decline is a very early event following LTx. Thirty-one consecutive patients (16 females/15 males), mean age 49 (+/-13) years, with emphysema, cystic fibrosis....../bronchiectasis or idiopathic pulmonary fibrosis were included in an analysis of renal function before and after LTx. The glomerular filtration rate (GFR) was measured using the (51)Cr-ethylenediaminetetra acetic acid plasma clearance single injection technique (mGFR) at baseline before transplantation and at 1, 2.......0001), acute renal failure within 2 weeks post-LTx (p = 0.0003), use of heart and lung machine (p = 0.04), and the use of ephedrine (p = 0.048), as well as increasing age, older than 18 years at LTx (p = 0.006). These data demonstrate that renal function, measured with an isotope method, decreases dramatically...

  8. Rapid decline in 51Cr-EDTA measured renal function during the first weeks following lung transplantation

    Hornum, Mads; Iversen, Martin; Steffensen, Ida; Hovind, Peter; Carlsen, Jørn; Andersen, Lars Willy; Steinbrüchel, Daniel Andreas; Feldt-Rasmussen, Bo Friis

    2009-01-01

    /bronchiectasis or idiopathic pulmonary fibrosis were included in an analysis of renal function before and after LTx. The glomerular filtration rate (GFR) was measured using the (51)Cr-ethylenediaminetetra acetic acid plasma clearance single injection technique (mGFR) at baseline before transplantation and at 1, 2......We previously described a 54% decline in renal function at 6 months after lung transplantation (LTx). We hypothesized that this decline is a very early event following LTx. Thirty-one consecutive patients (16 females/15 males), mean age 49 (+/-13) years, with emphysema, cystic fibrosis...

  9. Arterio-venous concentration difference of [51Cr]EDTA after a single injection in man. Significance of renal function and local blood flow

    Rehling, M; Hyldstrup, Lars; Henriksen, Jens Henrik

    1989-01-01

    The present investigation was undertaken in order to study (1) the difference in arterial (Ca) and venous (Cv) concentration of [51Cr]EDTA (ethylenediaminetetraacetate) after a single intravenous injection, (2) the impact of different physiological variables on this difference, and (3) the error...... 180-300 min post-injection (p.i.) Cv was 5.9% higher than Ca (range 0.5-13.9%, P less than 0.001). The more reduced renal function, the smaller was the concentration difference. The areas under the arterial and the venous plasma concentration curves did not differ significantly at either 0-infinity or...... 0-300 min p.i. whereas the venous area 0-100 min p.i. underestimated the arterial area in the same period by 4.1% (P less than 0.05). In a computer simulation model, variation in the forearm capillary permeability-surface area product did not have any significant influence on the Cv-Ca difference...

  10. Kidney function measured by clearance. Methods and indications. An update; Zur Messung der Nierenfunktion durch Clearancebestimmungen. Methoden und Indikationen. Ein Update

    Durand, E. [Universitaetskrankenhaus Bicetre, Paris (France); Mueller-Suur, R. [Karolinska Inst., Danderyds Krankenhaus und Aleris Fysiologlab, Stockholm (Sweden)

    2010-09-15

    Renal function impairment can be monitored by many tests. Measurement of plasma-creatinine level is the most used method, 24 h plasma-creatininclearance with urine collection is used by others and also other alternative but indirect methods exist. However, the use of radionuclide-clearances is by far the easiest performed method with the highest accuracy and precision and gives very low irradiation dose. In the following we will discuss the different radiopharmaceuticals in use, their plus and minus, the different clearance methods in use, their limitations and give some clinically important indications to perform clearance investigations according to consensus reports. Summarizing the use of plasma clearance of 51-Cr-EDTA after a single injection with one blood sample can be generally recommended, however with some modifications in special clinical situations, which are pointed out. Please note, that this paper is, for a significant part, an update of a previous paper published 2003 in ''Der Nuklearmediziner'' (orig.)

  11. Simplified methods for assessment of renal function as the ratio of glomerular filtration rate to extracellular fluid volume

    Jødal, Lars; Brøchner-Mortensen, Jens

    2012-01-01

    contact with the ‘regulator’ (i.e. the kidneys). Aim: The aim of the present study was as follows: to analyse two published calculation methods for determining ECV and GFR/ECV; to develop a new simple and accurate formula for determining ECV; and to compare and evaluate these methods. Materials and...... methods: GFR was determined as 51Cr-EDTA clearance. The study comprised 128 individuals (35 women, 66 men and 27 children) with a full 51Cr-EDTA plasma concentration curve, determined from injection until 4–5 h p.i. Reference values for GFR and ECV were calculated from the full curve. One......-pool approximations Cl1 and V1 were calculated using only the final-slope curve. Four calculation methods were compared: simple one-pool values; GFR/ECV according to Peters and colleagues; ECV according to Brøchner-Mortensen (BM); and ECV according to a new method (JBM): y=2x – 1, where x = Cl1/Cl and y = V1/ECV...

  12. Method of mucociliary clearance assessment

    Danilova, Tatiana V.; Manturov, Alexey O.; Ermakov, Igor Y.; Mareev, Gleb O.; Mareev, Oleg V.

    2016-04-01

    The article is devoted to the research capabilities of mucociliary clearance in the nasal cavity and paranasal sinuses using modern techniques of digital video recording and processing. We describe the setup and software for this method and the results of our research. Using microscope and digital camera we can provide a good method to study mucociliary clearance and by usage of special software we able to measure some characteristic of nasal mucosae and its main function.

  13. Revisiting normal {sup 51}Cr-ethylenediaminetetraacetic acid clearance values in children

    Piepsz, A.; Tondeur, M. [Department of Radioisotopes, CHU St Pierre, Brussels (Belgium); Ham, H. [Department of Nuclear Medicine, UZ Ghent, Ghent (Belgium)

    2006-12-15

    Normal {sup 51}Cr-ethylenediaminetetraacetic acid (EDTA) clearance values as a function of age were published a number of years ago. These values were based on data from children with a normal left to right ratio and a normal appearance on DMSA scintigraphy, despite the presence of an acute renal infection. At that time, the authors were unaware that hyperfiltration is a common phenomenon in patients with acute renal infection and that their normal values could have been significantly overestimated. The present work therefore aimed to re-appraise these normal values. In a first step, in order to verify the previous results, the same type of population was selected, namely patients with present or past urinary tract infection but normal images and a normal left to right ratio on DMSA scintigraphy. In a second step, the selection was based on patients who had had no recent urinary tract infection. In both series, a single blood sample method was used for the evaluation of {sup 51}Cr-EDTA clearance. In the first group of patients, the results obtained were almost identical to those previously published. In the second group of patients, the results were significantly lower: after 2 years of age, the mean GFR value was 104 ml/min/1.73 m{sup 2} (10th and 90th percentiles 81 and 135 ml/min/1.73 m{sup 2}, respectively), compared with 117 ml/min/1.73 m{sup 2} in the first group. The data of the second group are probably more representative of the true normal GFR values and can be applied to the entire paediatric population. (orig.)

  14. The clearance concept with special reference to determination of glomerular filtration rate in patients with fluid retention

    Henriksen, Ulrik L; Henriksen, Jens H

    2014-01-01

    be assessed to obtain a correct measurement of the glomerular filtration rate (GFR). In theory, total plasma clearance with late samples (24-h, 48-h) may be applied in patients with fluid retention, but validation hereof has not been performed. Until such studies are completed, it is recommended that......In subjects without fluid retention, the total plasma clearance of a renal filtration indicator (inulin, (99m) Tc-DTPA, (51) Cr-EDTA) is close to the urinary plasma clearance. Conversely, in patients with fluid retention (oedema, pleural effusions, ascites), there is a substantial discrepancy...... patients with fluid retention have their GFR measured by a urinary plasma clearance technique with controlled quantitativeurinary sampling within a few hours after indicator injection....

  15. Måling af nyrefunktion under cytostatisk behandling

    Hartlev, Louise Brøndt; Bøje, Charlotte Rotbøl; Bluhme, Henrik;

    2008-01-01

    INTRODUCTION: Some cytostatics, used in the treatment of cancer, are excreted by the kidneys and may be nephrotoxic. The glomerular filtration rate (GFR) represents a method for reliable assessement of the 51Cr-EDTA plasma clearance before and during treatment with nephrotoxic drugs. The aim of...

  16. Clearance detector and method for motion and distance

    Xavier, Patrick G. (Albuquerque, NM)

    2011-08-09

    A method for correct and efficient detection of clearances between three-dimensional bodies in computer-based simulations, where one or both of the volumes is subject to translation and/or rotations. The method conservatively determines of the size of such clearances and whether there is a collision between the bodies. Given two bodies, each of which is undergoing separate motions, the method utilizes bounding-volume hierarchy representations for the two bodies and, mappings and inverse mappings for the motions of the two bodies. The method uses the representations, mappings and direction vectors to determine the directionally furthest locations of points on the convex hulls of the volumes virtually swept by the bodies and hence the clearance between the bodies, without having to calculate the convex hulls of the bodies. The method includes clearance detection for bodies comprising convex geometrical primitives and more specific techniques for bodies comprising convex polyhedra.

  17. Aspects of osseous, peritoneal and renal handling of bisphosphonate during peritoneal dialysis: a methodological study

    Joffe, P; Henriksen, Jens Henrik Sahl

    1996-01-01

    -acetic acid (51Cr-EDTA). Eight patients on CAPD were studied cross-sectionally. The mean plasma clearances of 99mTc-MBP and 51Cr-EDTA in the steady state (4h) were 38.2 and 12.2 ml min-1 (p < 0.01), the peritoneal clearances (0-4 h) were 5.2 and 7.2 ml min-1 (p < 0.01), and the renal clearances (0-4 h) were 2......Tc-MBP equal the clearances of 51Cr-EDTA is correct from a clinical point of view. We found that the uptake of the tracers in soft tissue and the renal handling of 51Cr-EDTA and 99mTc-MBP are also similar. The differences between the clearance values for 51Cr-EDTA and 99mTc-MBP may be explained by their...

  18. Stability, protein binding and clearance studies of [99mTc]DTPA. Evaluation of a commercially available dry-kit

    Rehling, M

    1988-01-01

    quality of a commercial [99mTc]DTPA preparation (C.I.S., France) with reference to stability, protein binding and accuracy of the determined plasma clearance values as a measure of GFR. The stability of the preparations was studied by thin-layer chromatography, the in vitro protein binding by Sephadex...... filtration after incubation with human serum albumin and in vivo protein binding by filtration of human plasma. The accuracy of the plasma clearance values was investigated by comparison with the simultaneously measured plasma clearance of [51Cr]EDTA. There was no detectable free pertechnetate or hydrolysed...... reduced technetium in eight vials five and six hours after the preparation. The in vitro protein binding 10 (20), 120 and 300 min after the preparation of eight vials was 2.3% (0.8%), 0.2% and 0.1%, respectively. The in vivo protein binding in 12 patients 5, 90 and 180 min after the injection was 0.3%, 0...

  19. Reliability of a 99sp(m)Tc-DTPA gamma camera technique for determination of single kidney glomerular filtration rate

    In a recent paper we described a method for calculation of single kidney glomerular filtration rate (SKGFR) from the 99sp(m)Tc-DTPA renogram obtained by gamma camera. In this paper the reliability of the method was compared to other methods for estimation of GFR in 20 unilaterally nephrectomized patients. The values for SKGFR obtained from the renograms and from the estimated endogenous creatinine clearances according to serum creatinine concentration and a nomogram were both accurate. The reliability of the renography method was significantly better judged by less variance in the estimates. SKGFR calculated from the plasma clearance of 51Cr-EDTA overestimated the renal clearance of inulin on an average by 11.3%. No difference was found in the variance of the values obtained from the renograms and from the plasma clearances of 51Cr-EDTA compared to the renal clearance of inulin. Apart from the inaccuracy in the GFR values calculated from the plasma clearance of 51Cr-EDTA, the reliability of these two methods was equal. (author)

  20. Influence of renal function on the elimination of morphine and morphine glucuronides

    Wolff, Jesper; Bigler, Dennis Richard; Christensen, C B; Rasmussen, S N; Andersen, H B; Tønnesen, K H

    1988-01-01

    The influence of renal function, measured by 51Cr-EDTA clearance, on morphine and morphine glucuronide kinetics has been studied in 13 patients after a single i.v. injection of morphine. Unconjugated morphine and morphine glucuronides were measured by a sensitive, specific RIA after extraction from...... plasma. No significant correlation was found between total body clearance of unconjugated morphine and 51Cr-EDTA clearance. However, patients with renal insufficiency had impaired elimination of morphine glucuronides, and the apparent clearance was significantly correlated with the 51Cr-EDTA clearance (r...

  1. A simple method for the verification of clearance levels for non-radioactive solid waste

    ANSTO's radiopharmaceutical production laboratories generate 25 m3 of solid waste per month. Most of this waste is not radioactive. Up until recently the non-radioactive waste was cleared from the controlled area and stored for 10 halflives prior to disposal as normal solid refuse. To eliminate the storage and ''double handling'' of the large quantities of non-radioactive waste a simple clearance method was devised to allow direct disposal. This paper describes how clearance levels were determined. Here the term ''clearance level'' is used as a general term for the release of material regardless of whether it was previously subject to regulatory control. This contrasts with the IAEA definition of a clearance level and highlights a potential problem with the implementation of exemption levels to keep material out of regulatory control and the use of clearance levels to allow removal of materials from regulatory control. Several common hand held contamination monitors were tested to determine their limits of detection and ability to meet these clearance levels. The clearance method includes waste segregation and size limitation features to ensure the waste is monitored in a consistent manner, compatible with the limits of detection. The clearance levels achieved were subsequently found to be compatible with some of the unconditional clearance levels in IAEA-TECDOC-855 and the measurement method also meets the required features of that document. The ANSTO non-radioactive waste clearance system has been in operation for more than 12 months and has proved simple and effective to operate. Approximately 12m3 of the solid waste is now been treated directly as normal solid refuse. This paper describes the ANSTO clearance system, the contamination monitor tests and details practical problems associated with the direct monitoring of solid waste, including averaging of the activity in the package. The paper also briefly highlights the potential problem with the use of exempted

  2. Evaluation of total renal function from 99mTc-MAG3 scintigraphy in children

    Aim: The aim of the present study was to evaluate the usefulness of dynamic scintigraphy in the assessment of total renal function in children. The Patlak slope of 99mTc-MAG3 renography curves were compared to the plasma clearance values of 51Cr-EDTA. Material and methods: The study sample consisted of 53 boys and 33 girls with various nephrologic disorders, referred for routine clinical reasons. The median age of the subjects was 5.1 years (range 0.3 - 14.1 years). Imaging procedure. In supine position, the patient received a bolus injection of 1 MBq/kg, (minimum 10 MBq) 99mTc-MAG3 and a posterior dynamic gamma camera registration was performed for 21 min using 1 frame per second during the first minute and thereafter 10 seconds frames. Data analysis. Time-activity curves were generated from manually drawn heart and renal regions of interest. The MAG3 uptake was calculated from the Patlak-Rutland plot of each kidney by linear curve fitting until the beginning of the excretory phase. A sum of the slope values was used as a measure of total renal MAG3 uptake. Cr-EDTA clearance. Glomerular filtration rate (GFR) was measured from the plasma clearance of 51Cr-EDTA using single injection, multiple-sample technique. After intravenous injection of 51Cr-EDTA (74 kBq/kg for children up to 7 years, 37 kBq/kg for children older than 7 years), blood samples were drawn at 5, 10, 15, 45, 60, 120 and 180 min for radioactivity measurement. The GFR was calculated according to Broechner-Mortensen and expressed in ml/min. Results: The absolute 51Cr-EDTA clearance varied from 9 to 143 ml/min. There was a close linear relationship between 51Cr-EDTA clearance and MAG3 uptake (Fig). The correlation coefficient was 0.90 and the regression equation (y=43.5 x + 664). Conclusions: In the present study, there was a good correlation between plasma clearance of 51Cr-EDTA and the sum of the Patlak slopes. The regression equation can be utilised to transform the 99mTc-MAG3 uptake to an estimate

  3. Glomerular filtration rate estimated from the uptake phase of 99mTc-DTPA renography in chronic renal failure

    Petersen, L J; Petersen, J R; Talleruphuus, U;

    1999-01-01

    The purpose of the study was to compare the estimation of glomerular filtration rate (GFR) from 99mTc-DTPA renography with that estimated from the renal clearance of 51Cr-EDTA, creatinine and urea.......The purpose of the study was to compare the estimation of glomerular filtration rate (GFR) from 99mTc-DTPA renography with that estimated from the renal clearance of 51Cr-EDTA, creatinine and urea....

  4. A computer program for unilateral renal clearance calculation by a modified Oberhausen method

    A FORTAN program is presented which, on the basis of data obtained with NUKLEOPAN M, calculates the glomerular filtration rate with sup(99m)Tc-DTPA, the unilateral effective renal plasma flow with 131I-hippuran, and the parameters for describing the isotope rephrogram (ING) with 131I-hippuran. The results are calculated fully automatically upon entry of the data, and the results are processed and printed out. The theoretical fundamentals of ING and whole-body clearance calculation are presented as well as the methods available for unilateral clearance calculation, and the FORTAN program is described in detail. The standard values of the method are documented, as well as a comparative gamma camera study of 48 patients in order to determine the accuracy of unilateral imaging with the NUKLEOPAN M instrument, a comparison of unilateral clearances by the Oberhausen and Taplin methods, and a comparison between 7/17' plasma clearance and whole-body clearance. Problems and findings of the method are discussed. (orig./MG)

  5. A camera based calculation of 99m Tc-MAG-3 clearance using conjugate views method

    Background: measurement of absolute or different renal function using radiotracers plays an important role in the clinical management of various renal diseases. Gamma camera quantitative methods is approximations of renal clearance may potentially be as accurate as plasma clearance methods. However some critical factors such as kidney depth and background counts are still troublesome in the use of this technique. In this study the conjugate-view method along with some background correction technique have been used for the measurement of renal activity in99mTc- MAG3 renography. Transmission data were used for attenuation correction and the source volume was considered for accurate background subtraction. Materials and methods: the study was performed in 35 adult patients referred to our department for conventional renography and ERPF calculation. Depending on patients weight approximately 10-15 mCi 99 Tc-MAG3 was injected in the form of a sharp bolus and 60 frames of 1 second followed by 174 frames of 10 seconds were acquired for each patient. Imaging was performed on a dual-head gamma camera(SOLUS; SunSpark10, ADAC Laboratories, Milpitas, CA) anterior and posterior views were acquired simultaneously. A LEHR collimator was used to correct the scatter for the emission and transmission images. Buijs factor was applied on background counts before background correction (Rutland-Patlak equation). gamma camera clearance was calculated using renal uptake in 1-2, 1.5-2.5, 2-3 min. The same procedure was repeated for both renograms obtained from posterior projection and conjugated views. The plasma clearance was also directly calculated by three blood samples obtained at 40, 80, 120 min after injection. Results: 99 Tc-MAG3 clearance using direct sampling method were used as reference values and compared to the results obtained from the renograms. The maximum correlation was found between conjugate view clearance at 2-3 min (R=0.99, R2=0.98, SE=15). Conventional posterior

  6. Body counter

    The paper gives a survey on some applications of the whole body counter in clinical practice and a critical study of its application as a routine testing method. Remarks on the necessary precautions are followed by a more detailed discussion of the determination of the natural potassium content, the iron metabolism, the vitamin B12 test, investigations of the metabolism of the bone using 47Ca and 85Sr, investigations with iodine and iodine-labelled substances, clearance investigations (in particular the 51Cr EDTA clearance test), as well as the possibilities of neutron activation in vivo. (ORU/AK)

  7. Measuring method for clearance of slightly contaminated scrap-metal

    The method is based on the measurement of dose rates by means of thermoluminescent dosemeters. It can be used for activity levels down to 400 Bq per kg and it has a measuring error of +-40%. The necessary recording time is approx. one week. (G.B.)

  8. A parameters optimization method for planar joint clearance model and its application for dynamics simulation of reciprocating compressor

    Hai-yang, Zhao; Min-qiang, Xu; Jin-dong, Wang; Yong-bo, Li

    2015-05-01

    In order to improve the accuracy of dynamics response simulation for mechanism with joint clearance, a parameter optimization method for planar joint clearance contact force model was presented in this paper, and the optimized parameters were applied to the dynamics response simulation for mechanism with oversized joint clearance fault. By studying the effect of increased clearance on the parameters of joint clearance contact force model, the relation of model parameters between different clearances was concluded. Then the dynamic equation of a two-stage reciprocating compressor with four joint clearances was developed using Lagrange method, and a multi-body dynamic model built in ADAMS software was used to solve this equation. To obtain a simulated dynamic response much closer to that of experimental tests, the parameters of joint clearance model, instead of using the designed values, were optimized by genetic algorithms approach. Finally, the optimized parameters were applied to simulate the dynamics response of model with oversized joint clearance fault according to the concluded parameter relation. The dynamics response of experimental test verified the effectiveness of this application.

  9. Estimation of hurdle clearance parameters using a monocular human motion tracking method.

    Krzeszowski, Tomasz; Przednowek, Krzysztof; Wiktorowicz, Krzysztof; Iskra, Janusz

    2016-09-01

    This paper presents a method of monocular human motion tracking for estimation of hurdle clearance kinematic parameters. The analysis involved 10 image sequences of five hurdlers at various training levels. Recording of the sequences was carried out under simulated starting conditions of a 110 m hurdle race. The parameters were estimated using the particle swarm optimization algorithm and they are based on analysis of the images recorded with a 100 Hz camera. The proposed method does not involve using any special clothes, markers, inertial sensors, etc. As the quality criteria, the mean absolute error and mean relative error were used. The level of computed errors justifies the use of this method to estimate hurdle clearance parameters. PMID:26838547

  10. Interscapular brown adipose tissue blood flow in the rat. Determination with 133xenon clearance compared to the microsphere method

    Astrup, A; Bülow, J; Madsen, J

    1984-01-01

    The xenon clearance method was adapted to continuous measurement of interscapular brown adipose tissue (ISBAT) blood flow in anesthetized rats. The ISBAT-blood partition coefficient for xenon was determined to 3.6 ml X g-1. The blood flow values obtained by Xe clearance were compared with flow...

  11. Comparison of 99mTc-MAG3 plasma clearance calculating methods [Bubeck and Russell (1996) methods] by single blood sampling

    This study was a comparison of the Bubeck and Russell (1996) methods, both of which are used to calculate 99mTc-MAG3 plasma clearance by single blood sampling in consideration of the distribution volume of patients. Quadratic polynominal approximation showed a strong correlation between the plasma clearance values obtained by the two methods. The quantitative values obtained by the Bubeck method tended to be lower than those obtained by the Russell (1996) method in the high clearance range. However, in the low to medium clearance range (below 250 ml/min/1.73 m2), there was almost no difference between the values, and the relationship between the values obtained by the two methods could be expressed by a straight regression line. A comparison of plasma clearance values according to difference in blood sampling time (35 min and 44 min sampling) in adults showed that there was no significant change in clearance regardless of the state of renal function. Correlation of the renal uptake rate obtained by the Bubeck method using a gamma camera could be expressed by a good straight regression line that passed around the origin of the coordinates. The results showed that, although the plasma clearance values obtained by the Bubeck method tended to be underestimated in the high clearance range compared with the values obtained by the Russell (1996) method, there was a very good correlation between the values obtained by the Bubeck method and renal uptake rate. (author)

  12. Measurement of glomerular filtration rate in adults: accuracy of five single-sample plasma clearance methods

    Rehling, M; Rabøl, A

    1989-01-01

    After an intravenous injection of a tracer that is removed from the body solely by filtration in the kidneys, the glomerular filtration rate (GFR) can be determined from its plasma clearance. The method requires a great number of blood samples but collection of urine is not needed. In the present...... determined simultaneously. Using these clearance values as reference the accuracy of six simplified methods were studied: five single-sample methods and one five-sample method. The standard error of estimate (SEE) of the single-sample methods ranged from 4.2 to 7.5 ml min-1 using EDTA, and from 3.8 to 6.3 ml...... min-1 using DTPA. SEE of the five-samples method was 3.0 ml min-1 (EDTA) and 3.1 ml min-1 (DTPA). The single-sample methods given by Christensen & Groth (1986) and by Tauxe (1986) are recommended for daily use, as SEE was small even at low GFR values. In patients with GFR less than 80 ml min-1, in...

  13. Large kidneys predict poor renal outcome in subjects with diabetes and chronic kidney disease.

    Vendrely Benoit; Beauvieux Marie-Christine; Barthe Nicole; Raffaitin Christelle; Montaudon Michel; Laurent François; Lasseur Catherine; Garcia Magalie; Rigalleau Vincent; Chauveau Philippe; Combe Christian; Gin Henri

    2010-01-01

    Abstract Background Renal hypertrophy occurs early in diabetic nephropathy, its later value is unknown. Do large kidneys still predict poor outcome in patients with diabetes and Chronic Kidney Disease (CKD)? Methods Seventy-five patients with diabetes and CKD according to a Glomerular Filtration Rate (GFR, by 51Cr-EDTA clearance) below 60 mL/min/1.73 m2 or an Albumin Excretion Rate above 30 mg/24 H, had an ultrasound imaging of the kidneys and were cooperatively followed during five years by ...

  14. Stress analysis method for clearance-fit joints with bearing-bypass loads

    Naik, R. A.; Crews, J. H., Jr.

    1989-01-01

    Within a multi-fastener joint, fastener holes may be subjected to the combined effects of bearing loads and loads that bypass the hole to be reacted elsewhere in the joint. The analysis of a joint subjected to search combined bearing and bypass loads is complicated by the usual clearance between the hole and the fastener. A simple analysis method for such clearance-fit joints subjected to bearing-bypass loading has been developed in the present study. It uses an inverse formulation with a linear elastic finite-element analysis. Conditions along the bolt-hole contact arc are specified by displacement constraint equations. The present method is simple to apply and can be implemented with most general purpose finite-element programs since it does not use complicated iterative-incremental procedures. The method was used to study the effects of bearing-bypass loading on bolt-hole contact angles and local stresses. In this study, a rigid, frictionless bolt was used with a plate having the properties of a quasi-isotropic graphite/epoxy laminate. Results showed that the contact angle as well as the peak stresses around the hole and their locations were strongly influenced by the ratio of bearing and bypass loads. For single contact, tension and compression bearing-bypass loading had opposite effects on the contact angle. For some compressive bearing-bypass loads, the hole tended to close on the fastener leading to dual contact. It was shown that dual contact reduces the stress concentration at the fastener and would, therefore, increase joint strength in compression. The results illustrate the general importance of accounting for bolt-hole clearance and contact to accurately compute local bolt-hole stresses for combined bearings and bypass loading.

  15. A simple method for the separation and quantitation of radiolabeled thyroid hormones in thyroxine clearance studies

    A method was developed to facilitate the separation and quantitation of radiolabeled thyroxine in plasma for thyroxine clearance studies. Following intravenous injection of radioactive thyroxine, the radiolabeled thyroid hormones were isolated from plasma protein and polar metabolites by solid phase extraction on a C18 sorbent bed. The individual thyroid hormones were then separated by ion-pair reversed phase chromatography and sequentially eluted through a UV detector and radiochromatographic detector. The radioactivity of individual radiolabeled thyroid hormones was corrected for recovery of carrier as determined from UV absorbance. The recoveries of thyroxine and 3,5,3'-triiodothyronine (T3) were 96% and 101%, respectively

  16. On the method for calculating unilateral renal clearance using 99mTc-MAG3 renal uptake ratio

    It has been reported that the renal clearance of 99mTc-mercaptoacetyltriglycine (99mTc-MAG3), a newly developed 99mTc-labeled renal tubular agent, effectively reflects renal plasma flow and serves as a useful parameter of renal function. In this study, we investigated on the method for calculating unilateral renal clearance of 99mTc-MAG3 using renal uptake ratio (RUR) and the conversion formula between RUR and renal clearance. Renography by 99mTc-MAG3 was performed in 38 cases with various renal functions and the renal clearance was estimated by three reported methods of one-point-venous-sampling. The results by Bubeck method were most consistent with the individual clinical data. The difference in the methodology of sample measurement or the type of scintillation camera did not affect the values of RUR. The correlation between renal clearance and RUR was not significantly different among the three groups of data acquisition time for RUR, i.e., 1-2 min., 1.5-2.5 min., and 2-3 min. after tracer injection. In summary, Bubeck method and RUR between 1-3 min. after injection seems to be suitable for the establishment or the conversion formula. Using this formula unilateral renal clearance of 99mTc-MAG3 could be reliably estimated without venous sampling. (author)

  17. Escaping the correction for body surface area when calculating glomerular filtration rate in children

    Piepsz, Amy; Tondeur, Marianne [CHU St. Pierre, Department of Radioisotopes, Brussels (Belgium); Ham, Hamphrey [University Hospital Ghent, Department of Nuclear Medicine, Ghent (Belgium)

    2008-09-15

    {sup 51}Cr ethylene diamine tetraacetic acid ({sup 51}Cr EDTA) clearance is nowadays considered as an accurate and reproducible method for measuring glomerular filtration rate (GFR) in children. Normal values in function of age, corrected for body surface area, have been recently updated. However, much criticism has been expressed about the validity of body surface area correction. The aim of the present paper was to present the normal GFR values, not corrected for body surface area, with the associated percentile curves. For that purpose, the same patients as in the previous paper were selected, namely those with no recent urinary tract infection, having a normal left to right {sup 99m}Tc MAG3 uptake ratio and a normal kidney morphology on the early parenchymal images. A single blood sample method was used for {sup 51}Cr EDTA clearance measurement. Clearance values, not corrected for body surface area, increased progressively up to the adolescence. The percentile curves were determined and allow, for a single patient, to estimate accurately the level of non-corrected clearance and the evolution with time, whatever the age. (orig.)

  18. Measurement of blood flow volume of ocular muscles by Xe-133 clearance method

    The blood flow volume of the ocular muscles was measured in 8 normal volunteers and 12 cases with miscellaneous opthalmic diseases by Xe-133 clearance method. The average of blood flow volume in the normal subjects was 7.45 ± 2.07 ml/min/100 g, and the blood flow volume ratio of right eye to left eye was 0.94 ± 0.07. The blood flow volume of the ocular muscles was decreased in the cases with stenosis of the internal carotid artery (n = 4, 4.3 ± 2.1 ml/min/100 g), glaucoma (n = 3, 4.7 ± 4.1 ml/min/100 g), arterial scleroses (n = 2, 3.8 ± 0.2 ml/min/100 g) and Takayasu's disease (n = 2, 5.6 ± 0.4 ml/min/100 g), and was increased in the acute inflammatory disease (n = 2, 21.5 ± 2.5 ml/min/100 g). Measurement of the blood flow volume of the ocular muscles using Xe-133 clearance method is useful to evaluate the circulatory abnormality in the ophthalmic diseases. (author)

  19. Radiolabel ratio method for measuring pulmonary clearance of intratracheal bacterial challenges

    Calculation of bacterial clearance is a fundamental step in any study of in situ lung antibacterial defenses. A method is described whereby about 85% of a radiolabeled bacterial inoculum was consistently introduced into the bronchopulmonary tree of a mouse by the intratracheal route. Mice were then killed 1 and 4 hours later; their lungs were removed aseptically and homogenized, and viable bacteria and radiolabel counts were determined. Radiolabel counts fell slowly, and more than 80% of the original radiolabel was still present in homogenized lung samples from animals sacrificed 4 hours after challenge. Bacteria/isotope ratios for the bacterial inoculum and homogenized lung samples from animals sacrificed immediately after challenge were very similar. Bacterial clearance values were the same whether computed from bacterial counts alone or according to a radiolabel ratio method whereby the change in the bacteria/isotope ratio in ground lung aliquots was divided by a similar ratio from bacteria used to inoculate animals. Some contamination resulted from oral streptococci being swept into the bronchopulmonary free during the aspiration process. This contamination was not a problem when penicillin was incorporated into the agar and penicillin-resistant strains were used for the bacterial challenges

  20. COMPARISON OF TWO METHODS TO INCREASE TIP CLEARANCE AND ITS EFFECT ON PERFORMANCE OF TURBOCHARGER CENTRIFUGAL COMPRESSOR STAGE

    SYED Noman Danish; MA Chaochen; YANG Ce; L(U) Wei

    2007-01-01

    Tip clearance between the blade tip and casing of a centrifugal compressor can be varied through two methods: by changing the blade height (M1) or by changing the casing diameter (M2). Numerical simulations are carried out to compare these two methods and their effect on the stage and impeller performance. The impeller and diffuser are connected through rotor Stator boundary using frozen rotor approach. Overall stage performance and the flow configuration have been investigated for nine tip clearance levels from no gap to 1 mm. Impeller and diffuser performances are also presented separately. It has been found that the overall and impeller performance are comparatively better for Ml below tip clearance of 0.5 mm whereas M2 is found advantageous above 0.5 mm of tip clearance. Both M1 and M2 show performance degradation with the increase in tip clearance. Two models have been proposed for the stage total pressure ratio and efficiency, which are found to be in agreement with experimental results. The impeller efficiency and the pressure ratio are found to be maximum at tip clearance of 0.1 mm for both the cases however minimum diffuser effectiveness is also observed at the same clearance level. Diffuser effectiveness is found to be maximum at zero gap for both cases. As it is practically impossible to have zero gap for unshrouded impellers so it is concluded that the Optimum thickness is 0.5 mm onwards for Ml and 0.5 mm for M2 in terms of diffuser effectiveness. Mass averaged flow parameters, entropy, blade loading diagram and relative pressure fields are presented, showing the loss production within the impeller passage with tip clearance.

  1. Method to improve the blade tip-timing accuracy of fiber bundle sensor under varying tip clearance

    Duan, Fajie; Zhang, Jilong; Jiang, Jiajia; Guo, Haotian; Ye, Dechao

    2016-01-01

    Blade vibration measurement based on the blade tip-timing method has become an industry-standard procedure. Fiber bundle sensors are widely used for tip-timing measurement. However, the variation of clearance between the sensor and the blade will bring a tip-timing error to fiber bundle sensors due to the change in signal amplitude. This article presents methods based on software and hardware to reduce the error caused by the tip clearance change. The software method utilizes both the rising and falling edges of the tip-timing signal to determine the blade arrival time, and a calibration process suitable for asymmetric tip-timing signals is presented. The hardware method uses an automatic gain control circuit to stabilize the signal amplitude. Experiments are conducted and the results prove that both methods can effectively reduce the impact of tip clearance variation on the blade tip-timing and improve the accuracy of measurements.

  2. Measuring glomerular filtration rate using 51Cr-EDTA: body surface area normalization before or after Bröchner-Mortensen correction?

    Pottel, Hans; Hoste, Liesbeth; De Waele, Liesbeth; Braat, Elke; Baete, Kristof; Goffin, Karolien; Levtchenko, Elena; Gheysens, Olivier

    2014-01-01

    Guidelines for measuring glomerular filtration rate (GFR) using Cr-EDTA require normalizing of GFR for body surface area (BSA) before applying the Bröchner-Mortensen (BM) correction. The guideline explicitly mentions the importance of performing BSA normalization before BM correction and that this is particularly important in children in whom the effects of BSA normalization are largest.

  3. Novel Cytochrome P450 Reaction Phenotyping for Low-Clearance Compounds Using the Hepatocyte Relay Method.

    Yang, Xin; Atkinson, Karen; Di, Li

    2016-03-01

    A novel cytochrome P450 (P450) reaction phenotyping method for low-clearance compounds has been developed for eight P450 enzymes (CYP1A2, 2B6, 2D6, 2C8, 2C9, 2C19, 3A, and 3A4) and pan-cytochrome using the hepatocyte relay approach. Selective mechanism-based inhibitors were used to inactivate the individual P450 enzymes during preincubation, and inactivators were removed from the incubation before adding substrates to minimize reversible inhibition and maximize inhibitor specificity. The inhibitors were quite selective for specific P450 isoforms using the following inhibitor concentrations and preincubation times: furafylline (1 µM, 15 minutes) for CYP1A2, phencyclidine (20 µM, 15 minutes) for 2B6, paroxetine (1.8 µM, 15 minutes) for CYP2D6, gemfibrozil glucuronide (100 µM, 30 minutes) for 2C8, tienilic acid (15 µM, 30 minutes) for 2C9, esomeprazole (8 µM, 15 minutes) for 2C19, troleandomycin (25 µM, 15 minutes) for 3A4/5, CYP3cide (2 µM, 15 minutes) for 3A4, and 1-aminobenzotriazole (1 mM, 30 minutes) supplemented with tienilic acid (15 µM, 30 minutes) for pan-cytochrome. The inhibitors were successfully applied to the hepatocyte relay method in a 48-well format for P450 reaction phenotyping of low-clearance compounds. This novel method provides a new approach for determining the fraction metabolized of low-turnover compounds that are otherwise challenging with the traditional methods, such as chemical inhibitors with human liver microsomes and hepatocytes or human recombinant P450 enzymes. PMID:26700955

  4. The parasite clearance curve

    White NJ

    2011-01-01

    Abstract Parasite clearance rates are important measures of anti-malarial drug efficacy. They are particularly important in the assessment of artemisinin resistance. The slope of the log-linear segment in the middle of the parasite clearance curve has the least inter-individual variance and is the focus of therapeutic assessment. The factors affecting parasite clearance are reviewed. Methods of presentation and the approaches to analysis are discussed.

  5. Optical Method for Real-Time Turbine Blade Tip Clearance Measurement Project

    National Aeronautics and Space Administration — Monitoring and controlling blade tip clearance of high pressure turbines are important for maintaining the integrity of the engine during its operating points and...

  6. Calculating Clearances for Manipulators

    Copeland, E. L.; Peticolas, J. D.; Ray, L. D.

    1983-01-01

    Set of algorithms rapidly calculates minimum safe clearances for remote manipulators. Such calculations are used in design of trajectories for manipulators to ensure they do not accidentally strike surrounding objects. Structural parts are considered as cylindrical shells having circular plane areas for ends. Clearance calculation method offers special benefits in industrial robotics, particularly in automated machining.

  7. Beta-2-microglobulin excretion: an indicator of long term nephrotoxicity during cis-platinum treatment?

    Sørensen, P G; Nissen, Mogens Holst; Groth, S; Rørth, M

    1985-01-01

    To evaluate the value of beta-2-microglobulin as an indicator of acute and long-term cis-platinum-induced nephrotoxicity, 51Cr-EDTA clearance and serum concentration and urinary excretion of beta-2-microglobulin were measured in 18 patients treated with a regimen including cis-platinum. Before......-microglobulin remained unchanged. The decrease in 51Cr-EDTA clearance was not correlated to either the peak increase in the beta-2-microglobulin excretion or to the time of occurrence of the peak (R = 0.3). Thus, it is not possible to predict the long-term nephrotoxicity of cis-platinum by measuring the beta-2...

  8. Monitoring kidney function in type 2 diabetic patients with incipient and overt diabetic nephropathy

    Rossing, Peter; Rossing, Kasper; Gaede, Peter;

    2006-01-01

    The purpose of this study was to assess agreement between glomerular filtration rate (GFR) and the decline in GFR estimated with the Modification of Diet in Renal Disease (MDRD) Study Group equation or the Cockcroft-Gault formula and measured by the plasma clearance of 51Cr-EDTA.......The purpose of this study was to assess agreement between glomerular filtration rate (GFR) and the decline in GFR estimated with the Modification of Diet in Renal Disease (MDRD) Study Group equation or the Cockcroft-Gault formula and measured by the plasma clearance of 51Cr-EDTA....

  9. Mucociliary clearance

    Munkholm, Mathias; Mortensen, Jann

    2014-01-01

    Mucociliary clearance has long been known to be a significant innate defence mechanism against inhaled microbes and irritants. Important knowledge has been gathered regarding the anatomy and physiology of this system, and in recent years, extensive studies of the pathophysiology related to lung...... diseases characterized by defective mucus clearance have resulted in a variety of therapies, which might be able to enhance clearance from the lungs. In addition, ways to study in vivo mucociliary clearance in humans have been developed. This can be used as a means to assess the effect of different...... pharmacological interventions on clearance rate, to study the importance of defective mucus clearance in different lung diseases or as a diagnostic tool in the work-up of patients with recurrent airway diseases. The aim of this review is to provide an overview of the anatomy, physiology, pathophysiology, and...

  10. Method and system for measuring gate valve clearances and seating force

    Casada, Donald A.; Haynes, Howard D.; Moyers, John C.; Stewart, Brian K.

    1996-01-01

    Valve clearances and seating force, as well as other valve operational parameters, are determined by measuring valve stem rotation during opening and closing operations of a translatable gate valve. The magnitude of the stem rotation, and the relative difference between the stem rotation on opening and closing provides valuable data on the valve internals in a non-intrusive manner.

  11. Catchment conceptualisation for examining applicability of chloride mass balance method in an area of historical forest clearance

    H. Guan; Love, A.; C. T. Simmons; Ding, Z; Hutson, J

    2009-01-01

    Among various approaches for estimating groundwater recharge, chloride mass balance (CMB) method is one of the most frequently used, in particular, for arid and semiarid regions. Widespread native vegetation clearance, common history in many areas globally, has changed land surface boundary condition, posing a question whether the current system has reached new chloride equilibrium for CMB application. To examine CMB applicability for catchments, conceptual catchment types of various chloride...

  12. Catchment conceptualisation for examining applicability of chloride mass balance method in an area with historical forest clearance

    H. Guan; Love, A. J.; C. T. Simmons; Hutson, J; Ding, Z

    2010-01-01

    Of the various approaches for estimating groundwater recharge, the chloride mass balance (CMB) method is one of the most frequently used, especially for arid and semiarid regions. Widespread native vegetation clearance, common in many areas globally, has changed the land surface boundary condition, posing the question as to whether the current system has reached new chloride equilibrium, required for a CMB application. Although a one-dimensional CMB can be applied at a point where the water a...

  13. PC-1 amino acid variant (K121Q) has no impact on progression of diabetic nephropathy in type 1 diabetic patients

    Jacobsen, Peter; Grarup, Niels; Tarnow, Lise; Parving, Hans-Henrik; Pedersen, Oluf

    2002-01-01

    Recently, an amino acid variant (K121Q) in the glycoprotein PC-1 (Q allele) has been associated with faster progression of diabetic nephropathy, as estimated by calculated creatinine clearance. We tested the impact of the PC-1 (K121Q) variant on loss of glomerular filtration rate (GFR) measured b...... the [(51)Cr]EDTA plasma clearance technique....

  14. In situ method for measurements of community clearance rate on shallow water bivalve populations

    Hansen, Benni W.; Dolmer, Per; Vismann, Bent

    2011-01-01

    air lift connected to a SCUBA diver pressure tank generating a continuous and gentle water circulation. This ensures a complete mixture of suspended particles, and thereby, a maximum filtration by the bivalves. An in situ fluorometer was mounted to record plant pigment reduction due to mussel...... clearance in real-time. To calibrate the in situ fluorometer triplicate water samples were obtained initially in each of the bivalve filtration measurements. The water samples were filtrated, extracted, and later analyzed for plant pigment concentration on a laboratory spectrophotometer. The main conclusion......An open-top chamber was designed for measuring ambient community clearance rate on undisturbed bivalve populations in the field. The chamber was pressed 5-10 cm down in the sediment on the mussel bed. It holds approximately 30-40 cm water column equal to a volume of 43-77 L. It was provided with an...

  15. Experimental and clinical studies on dynamic circulation of intervertebral discs by radiation clearance method

    Few studies on the mechanism of dynamic circulation in intervertebral discs are reported. The purpose of this study is to clarify the dynamic mechanism of circulation in the lumbar intervertebra discs with radioisotope clearance, experimentally and clinically. Rabbits were used as experimental animals and were divided into two groups, normal and artificially injured. I131-sodium was injected into them and the clearance was followed. Injected I131-sodium was cleared in the order of; 1) discs with injured annulus fibrosus, 2) discs with injection of α-chymotrypsin, 3) discs with injuries in the border between vertebral body and annulus fibrosus, 4) and normal discs. Human degenerated discs were also used for this study. In the clinical cases, I131-sodium was cleared faster in the degenerated discs than in the normal. The pathway for I131-sodium to be cleared is supposed to be extravascular and interstitial spaces in the disc. (author)

  16. Analysis of Robot Accuracy Assessed via its Joint Clearance by Virtual Prototyping Method

    GUO Ling; WANG Li-hong; ZHANG Yu-ru

    2004-01-01

    This paper discusses how joint clearance influences robot end effector positioning accuracy and a robot accuracy analysis approach based on a virtual prototype is proposed. First, a 5-DOF( Degree of freedom) rneurosurgery robot was introduced. Then we built its virtual prototype, made movement planning and measured the manipulator tip accuracy, through which this robot accuracy portrait was obtained. Finally,in order to validate the robot accuracy analysis approach which is based on a virtual prototype, the result was compared with that from a model built by robot forward kinematics and robot differential kinematics.The robot accuracy analysis approach presented in this paper gives a new way to enhance robot design quality, and help to optimize the control and programming of the robot.

  17. Effect of renal nerve activity on tubular sodium and water reabsorption in dog kidneys as determined by the lithium clearance method

    Abildgaard, U; Holstein-Rathlou, N H; Leyssac, P P

    1986-01-01

    reabsorption of sodium and water increased significantly by 9 +/- 2% and 8 +/- 2%. Low-frequency electrical stimulation of the distal nerve bundle of the denervated kidney caused a significant decrease in urine flow rate (37 +/- 6%), sodium clearance (31 +/- 4%), lithium clearance (17 +/- 5%) and in fractional......The reliability of the lithium clearance method in studies of the effect of renal nerve activity upon tubular sodium and water handling in the dog kidney was investigated. Following unilateral acute surgical denervation of the kidney a significant increase in urinary flow rate (40 +/- 7%), sodium...... lithium clearance (18 +/- 5%). Calculated absolute proximal reabsorption rate increased significantly by 17 +/- 3%, while calculated absolute rates of distal sodium and water reabsorption decreased significantly by 16 +/- 5% and 16 +/- 5%. These changes in tubular sodium and water reabsorption during...

  18. Study on clearance system

    The clearance system is a legal word to define as 'the waste not requiring treatment as radioactive waste' on the regulatory control. JNES supports NISA on the approval and the confirmation of clearance measurement by the operator. The objective of this study is to establish technical base of the validation method of the clearance measurement for various objects. In reactor facilities, the statistical sampling measurement technique may be applied to large scale objects. In this study, the criteria of the techniques were examined, and the strategy for setting of radioactivity concentration evaluation level was prepared. In uranium processing facilities, simulation sources to apply to a validity confirmation examination of the measuring equipment were made, and these applicability and problem were studied. The method of the validity evaluation of the performance confirmation of the measuring equipment was devised by measurement experiment using this source. The manual for unexpected incidents which maintained in FY2011 was reviced by reflection of the experience of the radioactivity concentration measurement of disaster waste contaminated by the accident of Fukushima Dai-ichi NPS. JNES also supports NISA technically for the issue on influence of fall out from Fukushima Dai-ichi NPS on clearance system and NR system. In addition, the latest situation of a clearance system operated in Europe was studied. (author)

  19. Validation of the flow-through chamber (FTC and steady-state (SS methods for clearance rate measurements in bivalves

    Poul S. Larsen

    2011-09-01

    To obtain precise and reliable laboratory clearance rate (filtration rate measurements with the ‘flow-through chamber method’ (FTC the design must ensure that only inflow water reaches the bivalve's inhalant aperture and that exit flow is fully mixed. As earlier recommended these prerequisites can be checked by a plot of clearance rate (CR versus increasing through-flow (Fl to reach a plateau, which is the true CR, but we also recommend to plot percent particles cleared versus reciprocal through-flow where the plateau becomes the straight line CR/Fl, and we emphasize that the percent of particles cleared is in itself neither a criterion for valid CR measurement, nor an indicator of appropriate ‘chamber geometry’ as hitherto adapted in many studies. For the ‘steady-state method’ (SS, the design must ensure that inflow water becomes fully mixed with the bivalve's excurrent flow to establish a uniform chamber concentration prevailing at its incurrent flow and at the chamber outlet. These prerequisites can be checked by a plot of CR versus increasing Fl, which should give the true CR at all through-flows. Theoretically, the experimental uncertainty of CR for a given accuracy of concentration measurements depends on the percent reduction in particle concentration (100×P from inlet to outlet of the ideal ‘chamber geomety’. For FTC, it decreases with increasing values of P while for SS it first decreases but then increases again, suggesting the use of an intermediate value of P. In practice, the optimal value of P may depend on the given ‘chamber geometry’. The fundamental differences between the FTC and the SS methods and practical guidelines for their use are pointed out, and new data on CR for the blue mussel, Mytilus edulis, illustrate a design and use of the SS method which may be employed in e.g. long-term growth experiments at constant algal concentrations.

  20. Study on clearance system

    The clearance system is a legal system to release 'the radioactive waste not requiring treatment as radioactive waste' from the regulatory control. JNES supports NISA on approval and confirmation of clearance measurement and judgment developed by the operator. The objective of this study is to establish technical base of the validation method of the clearance measurement for various objects. In reactor facilities, the bulk measurement technique or the statistical sampling measurement technique may be applied to large scale objects or concrete walls. In this study, the criteria of those techniques were examined. In uranium processing facilities, it is important to confirm surface state of the object in case of detecting alpha rays. The result of the examination about the influence of the surface rust in the uranium clearance measurement by the alpha ray measurement showed that the pollution was distributed in rust layer uniformly. This result will be reflected to the revision of the Ministerial Ordinance on Clearance in 2011FY. To develop a manual for unexpected incidents, the response procedure for an unexpected incident was prepared, including a response system. (author)

  1. Study on the delay phenomenon in various types of deltopectoral flaps using the xenon-133 clearance method

    During the past five years, we have measured the skin blood flow in various types of deltopectoral flaps by the Xenon-133 clearance method and have studied the delay phenomenon and optimum transfer time. The clearance rate of the first component, indicating the skin blood flow, was compared individually before and successively after a delay procedure at the deltoid region by taking the pre-operative value as 100 percent. The changes in the skin blood flow in the flaps were studied for the following five groups in order to ascertain if there were any differences in recovery patterns. 1) Type I (U-shaped, undermined D-P flap): In 25 cases, the regional blood flow decreased once, recovering to control values within one to three weeks. In some cases, the recovery exceeded the control values after 10 days. 2) Type II (U-shaped, raised deltoid flap): In 18 cases, recovery of the skin blood flow was slower than in Type I, reaching control values in the second to third week. 3) Type III (lining D-P flap with a split-skin graft): In 10 cases, the skin blood flow was better than in Type I, with recovery exceeding control values after one week and continuing to increase with time. 4) Type IV (tubed D-P flap): Recovery of the skin blood flow was observed at two to four days showing better than in Type I. This procedure was considered to be highly reliable and to have wide indications. 5) Type V (bipedicled, raised D-P flap): Recovery of the skin blood flow was higher in the base than in the deltoid region, but the difference gradually decreased post-operatively with time. The time of the lateral incision was found to be critical because of the influence of the possibility of occurrence of a post-operative inversion of the recovery rate. (author)

  2. Catchment conceptualisation for examining applicability of chloride mass balance method in an area with historical forest clearance

    H. Guan

    2010-07-01

    Full Text Available Of the various approaches for estimating groundwater recharge, the chloride mass balance (CMB method is one of the most frequently used, especially for arid and semiarid regions. Widespread native vegetation clearance, common in many areas globally, has changed the land surface boundary condition, posing the question as to whether the current system has reached new chloride equilibrium, required for a CMB application. Although a one-dimensional CMB can be applied at a point where the water and chloride fluxes are locally in steady state, the CMB method is usually applied at a catchment scale owing to significant lateral flows in mountains. The applicability of the CMB method to several conceptual catchment types of various chloride equilibrium conditions is examined. The conceptualisation, combined with some local climate conditions, is shown to be useful in assessing whether or not a catchment has reached new chloride equilibrium. The six conceptual catchment types are tested with eleven selected catchments in the Mount Lofty Ranges (MLR, a coastal hilly area in South Australia having experienced widespread historical forest clearance. The results show that six of the eleven catchments match a type VI chloride balance condition (chloride non-equilibrium with a gaining stream, with the ratios of stream chloride output (O over atmospheric chloride input (I, or catchment chloride O/I ratios, ranging from 2 to 4. Two catchments match a type V chloride balance condition (chloride non-equilibrium with a losing stream, with catchment chloride O/I ratios about 0.5. For these type V and type VI catchments, the CMB method is not applicable. The results also suggest that neither a chloride O/I ratio less than one nor a low seasonal fluctuation of streamflow chloride concentration (a factor below 4 guarantees a chloride equilibrium condition in the study area. A large chloride O/I value (above one and a large fluctuation of streamflow chloride

  3. Study on clearance system

    The clearance system is a legal system to release 'the radioactive waste not requiring treatment as radioactive waste' from the regulatory control. JNES supports Nuclear Regulatory Agency on approval and confirmation of clearance measurement and judgment developed by the operator. The objective of this study is to establish technical base of the validation method of the clearance measurement for various objects. In uranium processing facilities, simulation sources emitting alpha-rays is used in a validity confirmation examination of the measuring equipment. In this study, these sources were examined by measuring alpha and beta spectra to evaluate the applicability and problem of these sources. In addition, the measuring method detecting gamma-rays was examined. This method can be applied to complicated objects. As a part to develop a manual for unexpected incidents in clearance system, a quick method for measurement of Strontium 90 was examined. In addition, the measuring methods for the judgment of the influence of fallout and for NR (Non-Radioactive) confirmation were examined. (author)

  4. Dynamic Ground Clearance

    Hamache, Violette

    2013-01-01

    The purpose of this work is to develop a test method which will consider the variation of the ground clearance when driving, the so-called dynamic ground clearance. This has been done through the analysis of a specific application: the tractors in grain used in Brazil. Series of real life tests are run in order to obtain data on the tire compressions and the suspension travels. The tractor used is a 6x4 and is loaded with a trailer. When investigating critical cases, the minimum dynamic groun...

  5. Determination of the liver clearance of 131 J-bromosulfophthalein with partially shielded whole-body counter - method and clinical results

    The aim of the study consisted first of all in working out a procedure to determine the liver clearance of 131J-bromosulfophthalien according to the Oberhausen method and to inquire into the usability and sphere of validity of the Oberhausen approach. Subsequently a collective of patients was to be tested in order to find out whether it is possible with the aid of the clearance value to differentiate between persons with healthy livers and persons with liver disturbances respectively to assess the severity of a functional liver disorder. As the investigations were carried through as a part of the clinical routine, the information obtained by the clearance concept as compared to sequential scintiscanning and compartment analysis was to be investigated at the same time. (orig./MG)

  6. Prediction of two-sample 99mTc-diethylene triamine pentaacetic acid plasma clearance from single-sample method

    The objective of this study was to develop an equation to predict dual plasma sample method (DPSM) 99mTc-diethylene triamine pentaacetic acid (99mTc-DTPA) plasma clearance from single plasma sample method (SPSM), and to clarify the condition in which DPSM can be substituted by SPSM in measurement of glomerular filtration rate (GFR). Patients with chronic kidney disease (CKD) were selected. Watson modified Christensen and Groth equation was used to calculate 99mTc-DTPA plasma clearance by SPSM (sGFR). The equation recommended by the Nephrourology Committee of the Society of Nuclear Medicine was used to calculate 99mTc-DTPA plasma clearance by DPSM (tGFR) in each patient. The difference between sGFR and tGFR was expressed as percent of the average of these two methods, and tGFR was predicted from sGFR. Plasma creatinine was measured by the kinetic picrate method, and GFR estimated by abbreviated modification of diet in renal disease (MDRD) equation (aGFR) and Cockcroft-Gault equation (cGFR) were evaluated as criteria in selection of DPSM and SPSM. Three hundred and sixty-nine patients with CKD were selected (208 male and 161 female). The average age and body weight were 51.4±15.5 years and 67.2±12.5 kg, respectively. The causes of CKD were glomerular disease, renal arterial stenosis, chronic tubulointerstitial disease, and other causes or causes unknown. The average tGFR was 62.9±36.5 ml/min/1.73 m2, ranging from 1-180 ml/min/1.73 m2. sGFR was significantly correlated with tGFR (r=0.9194, p2; in contrast, then tGFR was±30 ml/min/1.73 m2, the difference was constant (-1.1%, 95% confidence interval -18.3%, 16.1%), and tGFR could be predicted from sGFR using the equation: predicted tGFR (ml/min/1.73 m2)=7 4244+0.7318 x sGFR+0.0022 x sGFR2 (n=299, r2=0.9428, p2, the diagnostic sensitivity of a cut off value of aGFR=45 ml/min/1.73 m2 was 91.8%, and recommended as a criterion in the selection of DPSM and SPSM. When GFR ≥30 ml/min/1.73 m2, tGFR can be predicted from s

  7. A single-injection, two-sample method for measuring renal 99mTc-MAG3 clearance in both children and adults

    We present a method for estimating 99mTc-MAG3 clearance from both a single injection and two blood samples that is valid for both adults and children. It was obtained by fitting a scaled two-compartment model (having only two adjustable parameters) to adult and pediatric data from multiple centers

  8. Identifying Minefields and Verifying Clearance: Adapting Statistical Methods for UXO Target Detection

    Gilbert, Richard O.; O' Brien, Robert F.; Wilson, John E.; Pulsipher, Brent A.; McKinstry, Craig A.; J. T. Broach, Russell S. Harmon, John H. Holloway, Jr.

    2003-09-01

    It may not be feasible to completely survey large tracts of land suspected of containing minefields. It is desirable to develop a characterization protocol that will confidently identify minefields within these large land tracts if they exist. Naturally, surveying areas of greatest concern and most likely locations would be necessary but will not provide the needed confidence that an unknown minefield had not eluded detection. Once minefields are detected, methods are needed to bound the area that will require detailed mine detection surveys. The US Department of Defense Strategic Environmental Research and Development Program (SERDP) is sponsoring the development of statistical survey methods and tools for detecting potential UXO targets. These methods may be directly applicable to demining efforts. Statistical methods are employed to determine the optimal geophysical survey transect spacing to have confidence of detecting target areas of a critical size, shape, and anomaly density. Other methods under development determine the proportion of a land area that must be surveyed to confidently conclude that there are no UXO present. Adaptive sampling schemes are also being developed as an approach for bounding the target areas. These methods and tools will be presented and the status of relevant research in this area will be discussed.

  9. Prediction of renal function (GFR) from cystatin C and creatinine in children: Body cell mass increases accuracy of the estimate

    Andersen, Trine Borup; Jødal, Lars; Bøgsted, Martin; J. Erlandsen, Erland; Eskild-Jensen, Anni; Frøkiær, Jørgen; Brøchner-Mortensen, Jens

    using robust regression in a forward, stepwise procedure. GFR (mL/min) was the dependent variable. The accuracy and precision of the prediction model were compared to other prediction models from the literature, using k-fold cross-validation. Local constants and coefficients were calculated for all...... glomerular filtration followed by catabolization in the tubular cells. We hypothesized that production rate is proportional to body cell mass (BCM) and inferred GFR (mL/min) to be proportional to BCM/CysC. MATERIAL AND METHODS: GFR was determined with 51Cr-EDTA-clearance in 131 children (52 girls, 79 boys....... CONCLUSION: The new equation predicts GFR with higher accuracy than other equations. Endogenous methods are, however, still not accurate enough to replace exogenous markers when GFR must be determined with high accuracy....

  10. Catchment conceptualisation for examining applicability of chloride mass balance method in an area of historical forest clearance

    H. Guan

    2009-11-01

    Full Text Available Among various approaches for estimating groundwater recharge, chloride mass balance (CMB method is one of the most frequently used, in particular, for arid and semiarid regions. Widespread native vegetation clearance, common history in many areas globally, has changed land surface boundary condition, posing a question whether the current system has reached new chloride equilibrium for CMB application. To examine CMB applicability for catchments, conceptual catchment types of various chloride equilibrium conditions are defined. The conceptualization, combined with some local climate conditions, is demonstrated to be useful in examining whether a catchment has reached new chloride equilibrium. The six conceptual catchment types are tested with eleven selected catchments in the Mount Lofty Ranges (MLR, a coastal hilly area in South Australia having experienced historical widespread forest clearance. The results show that six of the eleven catchments match type VI chloride balance condition (chloride non-equilibrium with a gaining stream, with the ratio of stream chloride output over atmospheric chloride input (catchment chloride O/I ranging from 2 to 4. Two catchments match type V chloride balance condition (chloride non-equilibrium with a losing stream, with catchment chloride O/I values about 0.5. For these catchments, the CMB method is not appropriate to apply. The results also suggest that neither a below-one chloride O/I value nor a low seasonal fluctuation of streamflow chloride concentration (a factor below 4 guarantees a chloride equilibrium condition in the study area. But a large chloride O/I value (above one and a large fluctuation of streamflow chloride concentration (a factor of 10 and above generally indicates either a chloride disequilibrium, or cross-catchment water transfer, or both, for which CMB is not applicable. Based on the regression between chloride O/I values and annual precipitation for type VI catchments, a catchment with

  11. Comparison of glomerular filtration rates by dynamic renal scintigraphy and dual-plasma sample clearance method in diabetic nephropathy

    Objective: To evaluate the accuracy of renal scintigraphy for the estimation of glomerular filtration rates (dGFR) in patients with diabetic nephropathy as compared to the conventional dual-plasma sample clearance method (pscGFR). Methods: Forty-six patients with diabetic nephropathy underwent both dynamic renal scintigraphy and dual-plasma sample measurement after 99Tcm-DTPA injection. Paired student t-test and correlation analysis were performed to compare dGFR and pscGFR (normalized to body surface area, 1.73 m-2). Results: The mean dGFR was higher than mean pscGFR ((51.08±26.78)ml·min-1 vs (44.06±29.43)ml·min-1, t=4.209, P=0.000). The dGFR correlated with pscGFR (r=0.923, P=0.000) linearly (regression equation: pscGFR=1.015 x dGFR -7.773, F=254.656, P=0.000). Conclusions: dGFR correlated well with pscGFR. Although it could not absolutely replace the latter in patients with diabetic nephropathy, dGFR could reasonably evaluate the filtration function for these patients. (authors)

  12. Renal impairment and late toxicity in germ-cell cancer survivors

    Lauritsen, J.; Mortensen, M. S.; Kier, M. G. G.; Christensen, I. J.; Agerbaek, M.; Gupta, Ramneek; Daugaard, G.

    2015-01-01

    cohort of germ-cell cancer survivors. Patients and methods BEP-treated patients (N = 1206) were identified in the Danish DaTeCa database, and merged with national registers to identify late toxicity. GFR were measured (51Cr-EDTA clearance) before and after treatment and at 1, 3 and 5-year follow-up. The...... renal function, had an increased risk of CVD and death. This risk depended on chronic kidney disease stage before treatment but not after treatment. ΔGFR had no influence on risk of late toxicity [death: hazard ratio (HR) 1.06, P = 0.50; CVD: HR 0.97, P = 0.61]. Conclusions Renal function after BEP is...

  13. 50 years follow-up on plasma creatinine levels after spinal cord injury

    Elmelund, Marlene; Oturai, P S; Biering-Sørensen, F

    2014-01-01

    119 patients with a traumatic SCI during the years 1944-1975 were included in the study. P-creatinine measurements, results from renography and glomerular filtration rate (GFR) measured with 51Cr-EDTA clearance were obtained from medical records and analyzed using a linear mixed model and linear...... regression analyses. RESULTS: When compared with median p-creatinine level in the first 5-year period after injury, the level of p-creatinine was stable throughout the first 30 years and decreased significantly after the 30th until 45th year post injury. Only patients with a functional distribution outside......STUDY DESIGN: Retrospective chart review. OBJECTIVES: To investigate the role of plasma creatinine (p-creatinine) in monitoring renal deterioration in patients up to 50 years after spinal cord injury (SCI). SETTING: The Clinic for Spinal Cord Injuries, Rigshospitalet, Denmark. METHODS: A total of...

  14. GFR Prediction From Cystatin C and Creatinine in Children

    Andersen, Trine Borup; Jødal, Lars; Boegsted, Martin; Erlandsen, Erland Jørn; Morsing, Anni; Frøkiær, Jørgen; Brøchner-Mortensen, Jens

    2012-01-01

    area, and SCr is serum creatinine level. The accuracy and precision of these models were compared with 7 previously published prediction models using random subsampling cross-validation. Local constants and coefficients were calculated for all models. Root mean square error, R2, and percentage of...... predictions within ±10% and ±30% of the reference GFR were calculated for all models. Based on 1,000 runs of the cross-validation procedure, median values and 2.5th and 97.5th quantiles of the validation parameters were calculated. Reference Test GFR measurement by 51Cr-EDTA clearance. Results The BCM model...... GFR <60 mL/min/1.73 m2. Lack of independent validation cohort. Conclusions The novel BCM model predicts GFR with higher accuracy than previously published models. The weight model is almost as accurate as the BCM model and allows for GFR estimation without knowledge of BCM. However, endogenous methods...

  15. Clearance gap flow: extended pneumatic measurements and simulations by discontinuous Galerkin finite element method

    Hála Jindřich

    2016-01-01

    Full Text Available In the present paper, new results of measurements of the compressible viscous fluid flow in narrow channels with parallel walls under the conditions of aerodynamic choking are presented. Investigation was carried out using the improved test section with enhanced capability to accurately set the parallelism of the channel walls. The measurements were performed for the channels of the dimensions: length 100 mm, width 100 mm and for various heights in the range from 0.5 mm to 4 mm. The results in the form of distribution of the static pressure along the channel axis including the detailed study of the influence of the deviation from parallelism of the channel walls are compared with previous measurements and with numerical simulations performed using an in-house code based on Favre averaged system of Navier-Stokes equations completed with turbulence model of Spalart and Allmaras and a modification of production term according to Langtry and Sjolander. The spatial discretization of the governing equations is performed using the discontinuous Galerkin finite element method which ensures high order spatial accuracy of the numerical solution.

  16. Clearance gap flow: extended pneumatic measurements and simulations by discontinuous Galerkin finite element method

    Hála, Jindřich; Luxa, Martin; Bublík, Ondřej; Prausová, Helena; Vimmr, Jan

    2016-03-01

    In the present paper, new results of measurements of the compressible viscous fluid flow in narrow channels with parallel walls under the conditions of aerodynamic choking are presented. Investigation was carried out using the improved test section with enhanced capability to accurately set the parallelism of the channel walls. The measurements were performed for the channels of the dimensions: length 100 mm, width 100 mm and for various heights in the range from 0.5 mm to 4 mm. The results in the form of distribution of the static pressure along the channel axis including the detailed study of the influence of the deviation from parallelism of the channel walls are compared with previous measurements and with numerical simulations performed using an in-house code based on Favre averaged system of Navier-Stokes equations completed with turbulence model of Spalart and Allmaras and a modification of production term according to Langtry and Sjolander. The spatial discretization of the governing equations is performed using the discontinuous Galerkin finite element method which ensures high order spatial accuracy of the numerical solution.

  17. In vitro catheter and sorbent-based method for clearance of radiocontrast material during cerebral interventions

    Background: Contrast-induced acute kidney injury is a severe condition resulting from the use of radiology contrast in patients with predisposing factors. Hypothesis: We hypothesized that a novel system including a device containing polymer resin sorbent beads and a custom-made suctioning catheter could efficiently remove contrast from an in vitro novel model of circulatory system (MOCS) mimicking the cerebral circulation. Methods: A custom-made catheter was built and optimized for cerebral venous approach. The efficiency of a system made of a polymer resin sorbent beads column (CST 401, Cytosorbents) and this particular catheter was tested in the MOCS running a solution composed of 0.9% saline and radio-contrast. During two series of 18 cycles of first-pass experiments we assessed the catheter's suctioning efficiency and the system's ability to clear radio-contrast injected into the MOCS's cerebral arterial segment. We also assessed the functioning and reliability of the MOCS. Results: Mean suctioning efficiency of the catheter was 84% ± 24%. The polymer sorbent column contrast removal rate was initially 96% and gradually decreased with subsequent cycles in a linear fashion during an experiment lasting approximately 90 minutes. The MOCS had a reliability of 0.9946×min−1 where 1 × min−1 was the optimum value. Conclusion: A system including a polymer resin sorbent beads column and a custom-made suctioning catheter had an excellent initial efficiency in quickly removing contrast from an artificial MOCS mimicking the cerebral circulation. MOCS is an inexpensive and relatively reliable custom-made system that can be used for training or testing purposes

  18. In vitro catheter and sorbent-based method for clearance of radiocontrast material during cerebral interventions

    Angheloiu, George O., E-mail: goangheloiu@drmc.org [Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Department of Cardiology, Dubois Regional Medical Center, Dubois, PA (United States); Hänscheid, Heribert; Reiners, Christoph [Department of Nuclear Medicine, University of Würzburg, Würzburg (Germany); Anderson, William D. [Cardiology Department, Exempla Healthcare, Denver, CO (United States); Kellum, John A. [CRISMA Center, Department of Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA (United States)

    2013-07-15

    Background: Contrast-induced acute kidney injury is a severe condition resulting from the use of radiology contrast in patients with predisposing factors. Hypothesis: We hypothesized that a novel system including a device containing polymer resin sorbent beads and a custom-made suctioning catheter could efficiently remove contrast from an in vitro novel model of circulatory system (MOCS) mimicking the cerebral circulation. Methods: A custom-made catheter was built and optimized for cerebral venous approach. The efficiency of a system made of a polymer resin sorbent beads column (CST 401, Cytosorbents) and this particular catheter was tested in the MOCS running a solution composed of 0.9% saline and radio-contrast. During two series of 18 cycles of first-pass experiments we assessed the catheter's suctioning efficiency and the system's ability to clear radio-contrast injected into the MOCS's cerebral arterial segment. We also assessed the functioning and reliability of the MOCS. Results: Mean suctioning efficiency of the catheter was 84% ± 24%. The polymer sorbent column contrast removal rate was initially 96% and gradually decreased with subsequent cycles in a linear fashion during an experiment lasting approximately 90 minutes. The MOCS had a reliability of 0.9946×min{sup −1} where 1 × min{sup −1} was the optimum value. Conclusion: A system including a polymer resin sorbent beads column and a custom-made suctioning catheter had an excellent initial efficiency in quickly removing contrast from an artificial MOCS mimicking the cerebral circulation. MOCS is an inexpensive and relatively reliable custom-made system that can be used for training or testing purposes.

  19. Gfr estimation using 99mTc DTPA gates method for assessment of early diabetic nephropathy - a comparison with 24-hour creatinine clearance

    To correlate Gates glomerular filtration rate (GGFR) using technetium-99m diethylene triaminepentacetic acid (99mTc DTPA) with 24-hour creatinine clearance (CRCL) and to establish relationship with duration of diabetes in patients with early diabetic nephropathy. Study Design: A cross-sectional comparative study carried out in Nuclear Medical Centre from Aug 2009 to Jan 2010 at Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan. Patients and Methods: A total of eighty three subjects were enrolled, who were divided into three groups; group 1 comprised 31 normotensive diabetics, group 2 had 37 hypertensive diabetics while group 3 had 15 normal subjects. The DTPA GFR and creatinine clearance in healthy subjects as well as diabetic patients were compared using the unpaired student's t-test. The linear association between GFR, creatinine clearance and disease duration was expressed by Pearson's correlation coefficient 'r' along with their significance levels. Results: Gates GFR showed hyperfiltration in normotensive diabetics (96.6 +- 3.3 ml/min/1.73 m/sub 2/), significantly (p<0.05) higher than controls (85.5 +- 5 ml/min/1.73 m/sub 2/), whereas hypertensive diabetics had a significantly lower (p<0.05) Gates GFR (76.8 +- 3.7) than that of controls. Significant degree of correlation existed between GGFR and CRCL in hypertensive diabetics (p<0.05, r=0.716) and controls (r=0.546). Gates GFR also showed good correlation with duration of diabetes in both diabetic groups as compared to that of CRCL. GGFR also correlated well with duration of hypertension 0.37 (0.31-0.43) as compared to CRCL 0.155 (0.15-0.16) in all groups. Conclusions: The 99mTc-DTPA clearance correlates significantly with 24-hour creatinine clearance as well as with disease duration and can provide a simple and convenient index of kidney function in patients of early diabetic nephropathy. (author)

  20. Re-entry flight clearance

    Juliana, S.

    2006-01-01

    The objective of the research was to identify and evaluate promising mathematical techniques for re-entry flight clearance. To fulfil this objective, two mathematical methods were investigated and developed: μ analysis for linear models and interval analysis for both linear and non-linear models. The stability of re-entry vehicles in the presence of model uncertainties was chosen as the clearance criterion, which is represented by two mathematical criteria: worst-case eigenvalues (linear...

  1. A combined study of Xe-133 clearance method and plethysmography for the estimate of shunt flow in the limb of the diabetic patients

    Disturbance of limb circulation is one of the major sign in the diabetic patients. Estimation of non-nutrient blood flow, ''Steal phenomenon'', in the legs of diabetic patients is useful for decision of therapy and prevention of diabetic gangrene. In this communication, the Xe-133 clearance method and the admittance plethysmography were simultaneously performed to estimate the non-nutrient shunt flow in the normal subjects and in the diabetic patients. From the Xe-133 clearance curve, blood flow rates in the muscle (Fm) and in the skin (Fs) were separately measured. When the volume percent of the calf tissues was expressed as 70% for the muscle and 10% for the skin, the relationship between the total blood flow (Fy) measured by the admittance plethysmography and the nutrient flow in the muscle and skin (Fn = 0.7Fm - 0.1Fs) was Fy = 1.09Fn + 0.05(ml/min/100g tissue). The sum of the blood flow in the bone and the non-nutrient shunt flow was about 11% of total blood flow in the calf. This value augmented by the peripheral heating, suggesting an increase of shunt flow. In the diabetic patients, the non-nutrient shunt flow increased associated with a reduction of the total flow in the calf. A combined study of the Xe-133 clearance method and the plethysmography is useful to estimate the non-nutrient flow in the pathologic condition of lower extremities

  2. Reliability of two different methods, whole body measurement and shoulder probe measurement, as judged from determinations of the renal clearance of orthoiodine hippuric acid

    This retrospective study was based on 1300 patients subjected to a series of radiopharmaceutical renal function studies, during which parallel determinations of the renal clearance rate were carried out using whole body measurements and shoulder probe measurements. It was the aim of this analysis to assess the reliability of shoulder probe measurements as compared to that of whole body measurements as well as their suitability for the diagnosis of postural perfusion disorders associated with nephroptosis and to define the generally acceptable normal ranges of the clearance of ortho-iodine hippuric acid on the basis of age and sex groups. As long as the values measured remained within normal limits, no major differences were discernable between the two methods. In reduced renal function, however, the shoulder probe measurements were biassed in a consistent way and tended to an overestimation of the renal performance that was proportionate to the degree of insufficiency. The intra-assay variations observed for the two methods did not differ from each other at a statistically significant level. The systematic error seen in connection with the shoulder probe measurements can in fact be easily eliminated. This method also offers the advantage of greater simplicity and can be carried out with the patient being in an upright position. Its suitability for the detection of postural perfusion disorders still remains to be proven in further studies. The results of the study are of clinical relevance inasfar as it was possible to determine lower limits of OJH clearance for the individual age and sex groups. (orig.)

  3. Validation of the flow-through chamber (FTC) and steady-state (SS) methods for clearance rate measurements in bivalves

    Larsen, Poul Scheel; Riisgård, Hans Ulrik

    2012-01-01

    a uniform chamber concentration prevailing at its incurrent flow and at the chamber outlet. These prerequisites can be checked by a plot of CR versus increasing Fl, which should give the true CR at all through-flows. Theoretically, the experimental uncertainty of CR for a given accuracy of...... can be checked by a plot of clearance rate (CR) versus increasing through-flow (Fl) to reach a plateau, which is the true CR, but we also recommend to plot percent particles cleared versus reciprocal through-flow where the plateau becomes the straight line CR/Fl, and we emphasize that the percent of...... be employed in e.g. long-term growth experiments at constant algal concentrations....

  4. Skeletal muscle oxygen pressure fields in artificially ventilated, critically ill patients

    The MDO (Mehrdraht Dostmund Oberflaeche) oxygen electrode was used in a study of skeletal muscle oxygen pressure fields, presented as histograms, in critically ill patients artificially ventilated with gas mixtures of different oxygen concentrations. The histograms were compared with forearm blood flow measurements performed with strain gauge plethysmography. Local blood flow and permeability-surface area product (PS) were also studied by the simultaneous clearances of 133xenon and 51Cr-EDTA. The histogram distribution type was normal, i.e. approximately Gaussian, at arterial oxygen pressure levels between 10 and 18 kPa. At arterial oxygen pressures outside this range the histogram distribution types were abnormal, i.e. they showed a non-symmetrical distribution of oxygen pressure values, but their mean was approximately the same as in the normal histogram. However, there were significantly higher tissue oxygen pressure mean values in the patients (3.43 kPa) than in a group of healthy human volunteers (2.25 kPa). Mean forearm blood flow and the clearances of 133xenon and 51Cr-EDTA showed marked variations during the measurements both intraindividually and interindividually. Mean forearm blood flow and mean clearances of 133xenon showed opposite trends compared with arterial oxygen pressures. Mean clearances of 51Cr-EDTA and mean PS showed minor variations at the different arterial oxygen pressure levels. (author)

  5. Role of mucus in gastric mucosal injury induced by local ischemia/reperfusion.

    Seno, K; Joh, T; Yokoyama, Y; Itoh, M

    1995-09-01

    The role of gastric mucus was evaluated in a rat model of gastric epithelial damage induced by local ischemia/reperfusion (I/R) stress. In this model, blood-to-lumen chromium 51-labeled ethylenediaminetetraacetic acid (51Cr-EDTA) clearance served as an index of injury. Tetraprenyl acetone (TPA; 100 mg, 200 mg/kg IP) was used to stimulate mucus production. Administration of TPA increased both the hexosamine content in gastric tissue and the amount of alcian blue-periodic acid Schiff (AB-PAS) stained mucus in the mucosa in a dose-dependent manner. Increases in 51Cr-EDTA clearance induced by I/R were significantly attenuated by TPA in a dose-dependent manner. N-acetyl-L-cysteine (NAC; 0.6%, 0.8%) was perfused into the gastric lumen to assess the effect of reduction in mucus on the injury induced by I/R. Although mean values of hexosamine content were increased by perfusion with NAC, AB-PAS-stained mucus in the mucosa was significantly decreased in a dose-dependent manner. Perfusion of NAC did not change basal 51Cr-EDTA clearance but significantly exacerbated the increase in clearance induced by I/R in a dose-dependent manner. These results indicate that gastric mucus protects the gastric mucosa against I/R stress in vivo. PMID:7665977

  6. Calculation of the renal clearance by dynamic measurement of the excreted activity

    Aim: In this paper we present a new method to measure the renal slope-clearance of Tc-99m-MAG-3 in a single-shot model (Excretion-clearance). Method: A renal scintigraphy with Tc-99m-MAG-3 was performed in 22 patients. The excreted activity of the tracer in the kidneys and the bladder was dynamically measured using a double-head gamma-camera. Additionally, the total absorption over the kidneys and the bladder was determined. The Excretion-clearance was calculated in a differential and an integral variant. Simultaneously the 2-compartment-clearance (Sapirstein-clearance), the Oberhausen-clearance and the Bubeck-clearance were calculated. Results: The Sapirstein-clearance is considered as the 'goldstandard' in a single-shot modell. The correlation of the Bubeck-clearance and the Oberhausen-clearance ranged from r=0.96 to r=0.97, the Excretion-clearance (differential-method) correlated with r=0.90. The absolute difference of the clearance-values was lowest comparing the Bubeck-clearance with the Sapirstein-clearance with an average difference of 11%, whereas the Excretion-clearance revealed at least an average difference of 21% and the Oberhausen-clearance of 24%. Discussion: The Excretion-clearance requires a more complicated protocoll measuring the clearance in comparison to the Bubeck-clearance. The results of the excretion-clearance differ more from the Sapirstein-clearance with regard to the examined patient population than the Bubeck-clearance. Regarding the theoretical basis of the methods, we expect advantages of the Excretion-clearance compared with the Bubeck-clearance in patients with compartmental disproportion or with a low clearance. We are going to prove this in combination with the above mentioned methodical improvements in a further study. (orig.)

  7. In vitro-in vivo extrapolation of quantitative hepatic biotransformation data for fish - I. A review of methods, and strategies for incorporating intrinsic clearance estimates into chemical kinetic models

    Nichols, John W.; Schultz, Irv R.; Fitzsimmons, Patrick N..

    2006-06-10

    Mammalian researchers have developed a stepwise approach to predict in vivo hepatic clearance from measurements of in vitro hepatic metabolism. The resulting clearance estimates have been used to screen drug candidates, identify potential drug-drug interactions, investigate idiosyncratic drug responses, and support toxicology risk assessments. In this report we review these methods, discuss their potential application to studies with fish, and describe how extrapolated values could be incorporated into well-known compartmental kinetic models. Empirical equations that relate extrapolation factors to chemical log Kow are given to facilitate the incorporation of metabolism data into bioconcentration and bioaccumulation models. Because they explicitly incorporate the concept of clearance, compartmental clearance volume models are particularly well suited for incorporating hepatic clearance estimates. The manner in which these clearance values are incorporated into a given model depends, however, on the measurement frame of reference. Procedures for the incorporation of in vitro metabolism data into physiologically based toxicokinetic (PBTK) models are also described. Unlike most compartmental models, PBTK models are developed to describe the effects of metabolism in the tissue where it occurs. In addition, PBTK models are well suited to modeling metabolism in more than one tissue.

  8. Renal clearance of melatonin

    Editorial Office

    1996-01-01

    Only two publications exist in which actual values for the renal clearance of intact melatonin in man is described. The melatonin clearance values were, however, obtained either after the oral intake of melatonin, or by applying different techniques for the determination of melatonin in urine and plasma. In this study, renal clearance of melatonin was determined during the hours where melatonin concentrations are relatively constant. Melatonin levels in plasma and urine respectively were e...

  9. Application of measuring 99mTc-MAG3 plasma clearance based on one-compartment model (MPC method) to renal transplantation

    Measurement of 99mTc-MAG3 plasma clearance (CLmag) based on one-compartment model (MPC method) was applied to renal transplantation and evaluated for the factors which might affect the calculated results, especially concerning renal depth. Correlation coefficient of CLmag between MPC method using real renal depth and Russell or Bubeck single sampling method was good (r=0.852 or 0.876, respectively). Regression equation between MPC method and Russell method was y=1.044x-3.0 and was more closer to y=x than that between MPC method and Bubeck method. CLmag of MPC method calculated by estimated renal depth from the abdominal thickness was also similar to that by real renal depth. Even if the fixed renal depth, 4 cm, was applied, the coefficient and regression equation between MPC method and Russell method were r=0.884 and y=1.004x-10.2. In conclusion, MPC method is applicable to the evaluation of renal transplants. Though measuring renal depth is best, calculation with fixed renal depth of 4 cm might be practically acceptable. (author)

  10. Security Clearance Tracking System

    National Archives and Records Administration — SCTS supports the adjudication process of private background investigations and clearances for potential employees, contractors, interns and student workers.

  11. Comparative animal studies for the determination of the extracellular space with several radioactively labelled substances

    The volume of the total extracellular space and of the extracellular space of the organs (liver, lungs, heart, spleen, brain) was determined with the aid of 5 radioactively labelled substances, each in 10 rats. The test substances (inulin-3H, 51Cr-EDTA, thiosulfate-35S, NH4-82Br, 60Co-vitamin B12) are described in the relevant literature as substances for the determination of the extracellular space and as clearance substances. (BSC/AK)

  12. Methods of precisely estimating the jacket pressure coefficient of controlled-clearance piston-cylinders at pressures up to 1 GPa

    Kajikawa, Hiroaki; Ide, Kazunori; Kobata, Tokihiko

    2011-10-01

    Deformational characteristics of a controlled-clearance piston-cylinder (CCPC) have been evaluated to precisely estimate the pressure dependence of its effective area. Among the experimentally accessible characteristics, the jacket pressure coefficient d, which denotes the relative change in the effective area due to applied jacket pressure pj, is examined in this paper. Two methods for precisely determining d at pressures up to 1 GPa are proposed. One is a comparative method that uses a set of a pressure balance and a multiplier as the tare gauge. The other is a new method that uses precise pressure transducers as monitoring devices. Both pj and weights loaded on the CCPC are changed so that the pressure generated by the CCPC remains constant, which is monitored by the transducers. d is estimated by the relative change in the weights loaded on the CCPC itself. Using the two methods, d for a 1 MPa kg-1 CCPC is measured at pressures up to 1 GPa. At each system pressure, d obtained by each method is approximated by a linear function of pj. The consistency of the fit values of d by the two methods is confirmed. The method using pressure transducers as monitoring devices is advantageous in terms of efficiency and operability especially at higher pressures.

  13. Turbomachinery Clearance Control

    Chupp, Raymond E.; Hendricks, Robert C.; Lattime, Scott B.; Steinetz, Bruce M.; Aksit, Mahmut F.

    2007-01-01

    Controlling interface clearances is the most cost effective method of enhancing turbomachinery performance. Seals control turbomachinery leakages, coolant flows and contribute to overall system rotordynamic stability. In many instances, sealing interfaces and coatings are sacrificial, like lubricants, giving up their integrity for the benefit of the component. They are subjected to abrasion, erosion, oxidation, incursive rubs, foreign object damage (FOD) and deposits as well as extremes in thermal, mechanical, aerodynamic and impact loadings. Tribological pairing of materials control how well and how long these interfaces will be effective in controlling flow. A variety of seal types and materials are required to satisfy turbomachinery sealing demands. These seals must be properly designed to maintain the interface clearances. In some cases, this will mean machining adjacent surfaces, yet in many other applications, coatings are employed for optimum performance. Many seals are coating composites fabricated on superstructures or substrates that are coated with sacrificial materials which can be refurbished either in situ or by removal, stripping, recoating and replacing until substrate life is exceeded. For blade and knife tip sealing an important class of materials known as abradables permit blade or knife rubbing without significant damage or wear to the rotating element while maintaining an effective sealing interface. Most such tip interfaces are passive, yet some, as for the high-pressure turbine (HPT) case or shroud, are actively controlled. This work presents an overview of turbomachinery sealing. Areas covered include: characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitations issues.

  14. Wear analysis of revolute joints with clearance in multibody systems

    Bai, ZhengFeng; Zhao, Yang; Wang, XingGui

    2013-08-01

    In this work, the prediction of wear for revolute joint with clearance in multibody systems is investigated using a computational methodology. The contact model in clearance joint is established using a new hybrid nonlinear contact force model and the friction effect is considered by using a modified Coulomb friction model. The dynamics model of multibody system with clearance is established using dynamic segmentation modeling method and the computational process for wear analysis of clearance joint in multibody systems is presented. The main computational process for wear analysis of clearance joint includes two steps, which are dynamics analysis and wear analysis. The dynamics simulation of multibody system with revolute clearance joint is carried out and the contact forces are drawn and used to calculate the wear amount of revolute clearance joint based on the Archard's wear model. Finally, a four-bar multibody mechanical system with revolute clearance joint is used as numerical example application to perform the simulation and show the dynamics responses and wear characteristics of multibody systems with revolute clearance joint. The main results of this work indicate that the contact between the joint elements is wider and more frequent in some specific regions and the wear phenomenon is not regular around the joint surface, which causes the clearance size increase non-regularly after clearance joint wear. This work presents an effective method to predict wear of revolute joint with clearance in multibody systems.

  15. Comparative evaluation of iohexol and inulin clearance for glomerular filtration rate determinations

    The authors have evaluated iohexol as a filtration marker in 150 children. The clearance of iohexol was compared with that of inulin or with a formula clearance. The single-sample clearance of iohexol showed a good correlation with the clearance of inulin. The clearance of iohexol correlated well with the formula clearance. The optimal blood sampling time for iohexol clearance determinations appears to be between 120 and 180 min after injection, at least in patient with relatively normal filtration rates. It is concluded that iohexol clearance is an accurate method of determining the glomerular filtration rate in clinical practice. 25 refs., 5 figs

  16. Noninvasive clearance of airway secretions.

    Hardy, K A; Anderson, B D

    1996-06-01

    or airway malacia. Use of positive pressure to maintain airway patency in these children allows cephalad clearance of secretions. Patients with segmental atelectasis, particularly related to asthma, may benefit from intrapulmonary percussive ventilator, positive expiratory pressure, or PDPV. Prevention of postoperative atelectasis is particularly well suited to positive expiratory pressure, which is not as painful as techniques using oscillations. Neurologically abnormal patients who are unable to cooperate with any active method are also treated using intrapulmonary percussive ventilator, PDPV, and suctioning, if necessary. Musculoskeletal abnormalities, muscular dystrophies, myasthenia gravis, poliomyelitis, or other similar diseases require stabilization of bellows function. Optimizing ventilation in patients with such abnormalities may require positive pressure ventilation either during sleep or continuously. Externally applied pressure, such as with the In-Exsufflator or the cyclically inflated pneumatic belt, can augment the patient's own efforts and is sometimes helpful. Normalizing the vital capacity and functional residual capacity typically helps to improve the ability to cough and clear secretions. Assisted cough devices or maneuvers are described in other papers by Bach and Hill. Not all patients who have weak muscles require nocturnal or continuous support, and may benefit from positive expiratory pressure mask treatments. Further studies are sorely needed for this population. Long-term controlled trials are urgently needed to help establish the best types of treatment for patients with CF and bronchiectasis. Such studies will become more complicated by the introduction of new treatments, such as DNase and other therapies that alter secretions, and may begin to change mucociliary or cough clearance. The selection of appropriate outcome measures is central to studying these questions, and it is unclear which are the most important. (ABSTRACT TRUNCATED

  17. Renal Clearance of Nanoparticles

    Choi, Hak Soo; Liu, Wenhao; Misra, Preeti; Tanaka, Eiichi; Zimmer, John P.; Ipe, Binil Itty; Bawendi, Moungi G.; Frangioni, John V.

    2007-01-01

    The field of nanotechnology holds great promise for the diagnosis and treatment of human disease. However, the size and charge of most nanoparticles preclude their efficient clearance from the body as intact nanoparticles. Without such clearance or their biodegradation into biologically benign components, toxicity is potentially amplified and radiological imaging is hindered. Using quantum dots (QDs) as a model system, we have precisely defined the requirements for renal filtration and urinar...

  18. Optimisation-based clearance

    Varga, Andras

    2002-01-01

    The basic feature of the optimisation-based clearance approach is to reformulate the clearance problems as equivalent minimum distance problems for which ”anti”-optimisation is performed to determine the worst-case parameter combination/ flight condition leading to worst performance. The basic requirements for the applicability of the optimisation-based approach are the availability of suitable parametric models describing the overall nonlinear dynamics of the augmented aircraft and of accomp...

  19. Antiepidermal growth factor variant III scFv fragment: effect of radioiodination method on tumor targeting and normal tissue clearance

    Shankar, Sriram [Department of Radiology, Duke University Medical Center, Durham, NC 27710 (United States); Vaidyanathan, Ganesan [Department of Radiology, Duke University Medical Center, Durham, NC 27710 (United States); Kuan, C.-T. [Department of Pathology, Duke University Medical Center, Durham, NC 27710 (United States); Bigner, Darell D. [Department of Pathology, Duke University Medical Center, Durham, NC 27710 (United States); Zalutsky, Michael R. [Department of Radiology, Duke University Medical Center, Durham, NC 27710 (United States) and Department of Pathology, Duke University Medical Center, Durham, NC 27710 (United States) and Department of Biomedical Engineering, Duke University, Durham, NC 27708 (United States)]. E-mail: zalut001@duke.edu

    2006-01-15

    Introduction: MR1-1 is a single-chain Fv (scFv) fragment that binds with high affinity to epidermal growth factor receptor variant III, which is overexpressed on gliomas and other tumors but is not present on normal tissues. The objective of this study was to evaluate four different methods for labeling MR1-1 scFv that had been previously investigated for the radioiodinating of an intact anti-epidermal growth factor receptor variant III (anti-EGFRvIII) monoclonal antibody (mAb) L8A4. Methods: The MR1-1 scFv was labeled with {sup 125}I/{sup 131}I using the Iodogen method, and was also radiohalogenated with acylation agents bearing substituents that were positively charged-N-succinimidyl-3-[*I]iodo-5-pyridine carboxylate and N-succinimidyl-4-guanidinomethyl-3-[*I]iodobenzoate ([*I]SGMIB)-and negatively charged-N-succinimidyl-3-[*I]iodo-4-phosphonomethylbenzoate ([*I]SIPMB). In vitro internalization assays were performed with the U87MG{delta}EGFR cell line, and the tissue distribution of the radioiodinated scFv fragments was evaluated in athymic mice bearing subcutaneous U87MG{delta}EGFR xenografts. Results and Conclusion: As seen previously with the anti-EGFRvIII IgG mAb, retention of radioiodine activity in U87MG{delta}EGFR cells in the internalization assay was labeling method dependent, with SGMIB and SIPMB yielding the most prolonged retention. However, unlike the case with the intact mAb, the results of the internalization assays were not predictive of in vivo tumor localization capacity of the labeled scFv. Renal activity was dependent on the nature of the labeling method. With MR1-1 labeled using SIPMB, kidney uptake was highest and most prolonged; catabolism studies indicated that this uptake primarily was in the form of {epsilon}-N-3-[*I]iodo-4-phosphonomethylbenzoyl lysine.

  20. Generic Clearance Values

    This paper analyzes the Generic Clearance Values established for natural and artificial radionuclides with the objective of evaluating their degree of conservatism in views of adopting them into the regulatory body. Generic clearance values for natural radionuclides have been chosen by experts judgments as the optimum boundary between, on the one hand, the ubiquitous unmodified soil concentrations and, on the other hand, activity concentrations in ores, mineral sands, industrial residues and wastes. For artificial radionuclides the clearance levels have been derived from the scenarios postulated in the document Safety Reports Series 44 of the IAEA considering quantitative exemption criteria. A set of 8 scenarios were postulated covering external, ingestion and inhalation exposure pathways. For each radionuclide, the generic clearance level was derived as the more restrictive value obtained from the scenarios, that is the lowest ratio between the applicable individual dose and the dose per unit activity concentration (Bq/g). The individual dose was calculated by a formula depending on each scenario and pathway, with different parameters, such as exposure time, dosimetric factors, dilution factor, density of the material, geometric factors, etc. It was concluded that the basis and parameters used for the derivation of the generic clearance levels are quite conservative and therefore its the adoption in Argentina has been recommended. It is expected that their implementation will contribute to optimize the regulatory management system. (authors)

  1. Generic clearance values

    This paper analyzes the Generic Clearance Values established for natural and artificial radionuclides with the objective of evaluating their degree of conservatism in views of adopting them into the regulatory body. Generic clearance values for natural radionuclides have been chosen by experts judgments as the optimum boundary between, on one hand, the ubiquitous unmodified soil concentrations and, on the other hand, activity concentrations in ores, mineral sands, industrial residues and wastes. For artificial radionuclides the clearance levels have been derived from the scenarios postulated in the document 'Safety Reports Series Nr 44' of the IAEA considering quantitative exemption criteria. A set of 8 scenarios were postulated covering external, ingestion and inhalation exposure pathways. For each radionuclide, the generic clearance level was derived as the more restrictive value obtained from the scenarios, that is the lowest ratio between the applicable individual dose and the dose per unit activity concentration (Bq/g). The individual dose was calculated by a formula depending on each scenario and pathway, with different parameters, such as exposure time, dosimetric factors, dilution factor, density of the material, geometric factors, etc. It was concluded that the basis and parameters used for the derivation of the generic clearance levels are quite conservative and therefore its the adoption in Argentina has been recommended. It is expected that their implementation will contribute to optimize the regulatory management system. (author)

  2. Gamma-scintigraphy as a novel method to study the distribution and clearance rate of different muco adhesive nasal delivery systems

    Nasal route has a high potential for drug delivery. One important limiting factor for nasal drug delivery is the rapid clearance of drugs from the nasal cavity. Several nasal drug delivery systems including different kinds of microspheres and liposomes have been tried for encapsulation of drugs and increasing the residence time in nasal cavity. In this study clearance rate of three kinds of microspheres (Alginate, PLGA and Dextran) and four kinds of liposomes (neutral, cationic, fusogenic and cationic-fusogenic) was determined. Lactose powder was used as negative control. Technetium pertechnetate labeling and gamma scintigraphy was used for precise and quantitative measurement of clearance rate of these delivery system. 99mTc labeled microspheres and liposomes were prepared using technetium pertechnetate in the presence of a potent reducing agent, st annus chloride. The labeling procedure was set in a manner that each 150 micro litter of liposome suspensions and each 3-5 mg of microspheres contained 2 MBq of radioactivity. Labeling efficiency was calculated by paper chromatography using acetone as mobile phase. Each delivery system containing 2 MBq of activity was sprayed into right nostril of four healthy volunteers and immediately after spraying, anterior view of nasal cavity was measured by a large field gamma camera equipped with a low-energy high resolution parallel collimator. One minute static views were repeated each half hour until 4 hours. Clearance rates were compared using two ROI; the initial site of deposition of sprays, and all of nasal cavity to nasopharynx. Clearance rate of each one of microspheres and liposomes was calculated after applying the physical decay corrections. The labeling efficiency for liposomes and microspheres calculated as 41.2% and 60.7% respectively. The cleared percent of delivery systems after 4 hours was determined as follows: neutral liposomes 18.7±3.9% cationic liposomes 43.7±2.1%; fusogenic liposomes 32.8±2

  3. Mucociliary clearance in chronic sinusitis

    Birdi, Surinder Mohan; Singh, Sunder; Singh, Ajit

    1998-01-01

    Mucociliary clearance is an important defence mechanism of upper and lower respiratory tracts. Any disturbance in the mechanism leads to stagnation of secretions and secondary infection with prolonged mucociliary clearance time. The present study was undertaken to establish normal mucociliary clearance time in our region and to evaluate its diagnostic and prognostic potential in chronic sinusitis of variable duration with and without obstructive diseases.

  4. Segmental tubular sodium reabsorption in type 1 diabetes

    Dieperink, H; Eshøj, O; Leyssac, P P;

    1993-01-01

    Segmental tubular sodium reabsorption in Type 1 (insulin-dependent) diabetes was measured in 36 patients in a cross-sectional study including one group (n = 13) without significant albuminuria (UalbV < 30 mg 24 h-1), one group (n = 16) with albuminuria in the range from 30 to 300 mg 24 h-1, and a...... group (n = 7) with nephropathy (UalbV > 300 mg 24 h-1). Lithium clearance was used to measure end proximal delivery. From end proximal delivery, 51Cr-EDTA clearance (GFR) and sodium clearance, segmental tubular reabsorption was calculated. For all patients, GFR was directly correlated with end proximal...

  5. Phagocytic Clearance in Neurodegeneration

    Sokolowski, Jennifer D.; Mandell, James W.

    2011-01-01

    The cellular and molecular mechanisms of phagocytic clearance of apoptotic cells and debris have been intensely studied in invertebrate model organisms and in the mammalian immune system. This evolutionarily conserved process serves multiple purposes. Uncleared debris from dying cells or aggregated proteins can be toxic and may trigger exaggerated inflammatory responses. Even though apoptotic cell death and debris accumulation are key features of neurodegenerative diseases, relatively little ...

  6. Modelling mucociliary clearance

    Smith, D.J.; Gaffney, E.A.; Blake, J R

    2008-01-01

    Mathematical modelling of the fluid mechanics of mucociliary clearance (MCC) is reviewed and future challenges for researchers are discussed. The morphology of the bronchial and tracheal airway surface liquid (ASL) and ciliated epithelium are briefly introduced. The cilia beat cycle, beat frequency and metachronal coordination are described, along with the rheology of the mucous layer. Theoretical modelling of MCC from the late 1960s onwards is reviewed, and distinctions between ‘phenomenolog...

  7. Comparison of quantitative autoradiographic and xenon-133 clearance methods: correlation of gray and white matter cerebral blood flow with compartmental blood flow indices

    The relationships between CBF in gray and white matter to those of the fast and slow components of xenon-133 clearance curves remain uncertain. CBF was measured in 13 anaesthetized baboons under a variety of conditions, using both the xenon-133 clearance technique and [14C]iodoantipyrine quantitative autoradiography. There was a linear relationship between CBF, as determined by the stochastic (height/area) analysis of the clearance curve, and mean CBF determined from the autoradiograms (r = 0.94, p less than 0.001, slope = 0.86 +/- 0.09). There was also a linear correlation between the fast-flow component (measured with xenon-133) and blood flow in the cerebral gray matter (measured with [14C]iodoantipyrine) (r = 0.92, p less than 0.001, slope = 0.69 +/- 0.15) and between the slow-flow component (with xenon-133) and blood flow in white matter (with [14C]iodoantipyrine) (r = 0.79, p less than 0.01, slope = 0.81 +/- 0.10). In the primate brain, the fast- and slow-flow indices therefore appear to be representative of CBF in gray matter and white matter, respectively, whereas the stochastic analysis provides a stable measure of mean CBF within the tissue monitored

  8. Comparison of quantitative autoradiographic and xenon-133 clearance methods: correlation of gray and white matter cerebral blood flow with compartmental blood flow indices

    Tuor, U.I.; Fitch, W.; Graham, D.I.; Mendelow, A.D.

    1986-08-01

    The relationships between CBF in gray and white matter to those of the fast and slow components of xenon-133 clearance curves remain uncertain. CBF was measured in 13 anaesthetized baboons under a variety of conditions, using both the xenon-133 clearance technique and (14C)iodoantipyrine quantitative autoradiography. There was a linear relationship between CBF, as determined by the stochastic (height/area) analysis of the clearance curve, and mean CBF determined from the autoradiograms (r = 0.94, p less than 0.001, slope = 0.86 +/- 0.09). There was also a linear correlation between the fast-flow component (measured with xenon-133) and blood flow in the cerebral gray matter (measured with (14C)iodoantipyrine) (r = 0.92, p less than 0.001, slope = 0.69 +/- 0.15) and between the slow-flow component (with xenon-133) and blood flow in white matter (with (14C)iodoantipyrine) (r = 0.79, p less than 0.01, slope = 0.81 +/- 0.10). In the primate brain, the fast- and slow-flow indices therefore appear to be representative of CBF in gray matter and white matter, respectively, whereas the stochastic analysis provides a stable measure of mean CBF within the tissue monitored.

  9. Cystatin C or Creatinine for Detection of Stage 3 Chronic Kidney Disease in Anorexia Nervosa.

    Delanaye, Pierre; Cavalier, Etienne; RADERMECKER, Régis; Paquot, Nicolas; Depas, Gisèle; Chapelle, Jean-Paul; Scheen, André; Krzesinski, Jean-Marie

    2008-01-01

    Background: Patients with anorexia nervosa (AN) are at a high risk of renal failure. Chronic kidney disease (CKD) is often missed in these patients because the serum creatinine is a poor marker of kidney function. We studied the utility of cystatin C to detect renal failure in this population. Method: Twenty-seven AN patients were studied. Glomerular filtration rates (GFR) were measured with the chromium-51- ethylenediaminetetraacetate ((51)Cr-EDTA) method. We compared the ability of creatini...

  10. Experimental inflammation following dural application of complete Freund's adjuvant or inflammatory soup does not alter brain and trigeminal microvascular passage

    Lundblad, Cornelia; Haanes, Kristian A; Grände, Gustaf;

    2015-01-01

    migraine for many patients, their site of action remains unidentified. It has been suggested that during migraine attacks the leakiness of the blood-brain barrier (BBB) is altered, increasing the passage of anti-migraine drugs. This study aimed to investigate the effect of experimental inflammation......, following dural application of complete Freund's adjuvant (CFA) or inflammatory soup (IS) on brain and trigeminal microvascular passage. METHODS: In order to address this issue, we induced local inflammation in male Sprague-Dawley-rats dura mater by the addition of CFA or IS directly on the dural surface....... Following 2, 24 or 48 h of inflammation we calculated permeability-surface area product (PS) for [(51)Cr]-EDTA in the trigeminal ganglion (TG), spinal trigeminal nucleus, cortex, periaqueductal grey and cerebellum. RESULTS: We observed that [(51)Cr]-EDTA did not pass into the central nervous system (CNS) in...

  11. Glomerular filtration rate by 51chomium and 113mindium labeled EDTA in horses

    The glomerular filtration rate was determined in nine healthy horses, six male and three female, aged two to 12-year-old, by means of 51Cr and 113mIn labeled EDTA single injection technique. The glomerular filtration rate was calculated from the plasma disappearance curve and the volume of distribution of the radiotracer, 51Cr-EDTA or 113mIn-EDTA. The result (mean +- standard deviation) was 148.80 +- 26.42 m L.min-1.100 kg. It is concluded that the measurement of glomerular filtration rate by 51Cr-EDTA or 113mIn-EDTA by single injection technique eliminates the bladder catheterization, and for its simplicity, convenience, accuracy, and low dose of radiation, can be used in horses as a method of choice in clinical routine. (author)

  12. Glomerular filtration rate by {sup 51}chomium and {sup 113m}indium labeled EDTA in horses; Taxa de filtracao glomerular pelo EDTA marcado com {sup 51}cromo e com {sup 113m}indio em equinos

    Maliska, C.; D' Almeida, J.; Pellegrini, P.M.; Schimit, T.S. [Hospital Central do Exercito (HCE), Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear; Pinho, W.R. [Centro de Ensino Superior, Valenca, RJ (Brazil). Fac. de Medicina Veterinaria; Lima, J.E.T. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear

    2009-07-01

    The glomerular filtration rate was determined in nine healthy horses, six male and three female, aged two to 12-year-old, by means of {sup 51}Cr and {sup 113m}In labeled EDTA single injection technique. The glomerular filtration rate was calculated from the plasma disappearance curve and the volume of distribution of the radiotracer, {sup 51}Cr-EDTA or {sup 113m}In-EDTA. The result (mean +- standard deviation) was 148.80 +- 26.42 m L.min{sup -1}.100 kg. It is concluded that the measurement of glomerular filtration rate by {sup 51}Cr-EDTA or {sup 113m}In-EDTA by single injection technique eliminates the bladder catheterization, and for its simplicity, convenience, accuracy, and low dose of radiation, can be used in horses as a method of choice in clinical routine. (author)

  13. Site clearance working group

    NONE

    1997-03-01

    The Gulf of Mexico and Louisiana continue to be areas with a high level of facility removal, and the pace of removal is projected to increase. Regulations were promulgated for the Gulf of Mexico and Louisiana requiring that abandoned sites be cleared of debris that could interfere with fishing and shrimping activities. The site clearance regulations also required verification that the sites were clear. Additionally, government programs were established to compensate fishermen for losses associated with snagging their equipment on oil and gas related objects that remained on the water bottoms in areas other than active producing sites and sites that had been verified as clear of obstructions and snags. The oil and gas industry funds the compensation programs. This paper reviews the regulations and evolving operating practices in the Gulf of Mexico and Louisiana where site clearance and fisherman`s gear compensation regulations have been in place for a number of years. Although regulations and guidelines may be in place elsewhere in the world, this paper focuses on the Gulf of Mexico and Louisiana. Workshop participants are encouraged to bring up international issues during the course of the workshop. Additionally, this paper raises questions and focuses on issues that are of concern to the various Gulf of Mexico and Louisiana water surface and water bottom stakeholders. This paper does not have answers to the questions or issues. During the workshop participants will debate the questions and issues in an attempt to develop consensus opinions and/or make suggestions that can be provided to the appropriate organizations, both private and government, for possible future research or policy adjustments. Site clearance and facility removal are different activities. Facility removal deals with removal of the structures used to produce oil and gas including platforms, wells, casing, piles, pipelines, well protection structures, etc.

  14. Family study of antipyrine clearance.

    Blain, P G; Mucklow, J C; Wood, P; Roberts, D F; Rawlins, M D

    1982-01-01

    Antipyrine clearance was measured in 208 healthy volunteers from 78 families. After the values had been corrected for weight and sex, antipyrine clearance was observed to be significantly correlated between siblings (r = 0.590) and between spouses (r = 0.320), but not between parents and their offspring. After the clearance values had been corrected for tobacco and oral contraceptive use, there was still no significant correlation between parents and offspring. These results are incompatible ...

  15. Study to improve the precision of calculation of split renal clearance by gamma camera method using 99mTc-MAG3

    Both fundamental and clinical studies were performed to improve the precision with which split renal clearance is calculated from the relation between renal clearance and the total renal uptake rate by using 99mTc-MAG3, which is mainly excreted into the proximal renal tubules. In the fundamental study, the most suitable kidney phantom threshold values for the extracted renal outline were investigated with regard to size, radioactivity, depth of the kidney phantom, and radioactivity in the background. In the clinical study, suitable timing to obtain additional images for making the ROI and the standard point for calculation of renal uptake rate were investigated. The results indicated that, although suitable threshold values were distributed from 25% to 45%, differences in size, solution activity, and the position of the phantom or BG activity did not have significant effects. Comparing 1-3 min with 2-5 min as the time for additional images for ROI, we found that renal areas using the former time showed higher values, and the correlation coefficient of the regression formula improved significantly. Comparison of the timing for the start of data acquisition with the end of the arterial phase as a standard point of calculating renal uptake rate showed improvement in the latter. (author)

  16. An accredited infrastructure for clearance of decommissioning waste

    The nuclear research reactors and a hot-cell facility at the Riso site in Denmark have been closed and are in the process of being decommissioned. This has prompted the development of an accredited infrastructure called the Clearance Function. This function is responsible for the activity concentration measurements of the clearance candidates and for the demonstration of compliance with the clearance levels for the released objects. The Clearance Function comprises laboratory facilities, measuring equipment, measuring procedures, waste handling software, software for clearance related calculations and trained personnel. An accreditation of the Clearance Function has been granted from the accreditation body, DANAK, according to the international standard ISO/IEC 17025:2005. DANAK is a member of ILAC, the International Laboratory Accreditation Cooperation. The Clearance Function has been accredited to measure surface-specific and mass-specific activities using surface contamination monitors and high purity germanium detectors. The germanium detectors are characterised and in each measurement they are calibrated using the ISOCS (registered) calibration software. Activity concentration measurements can be made on items as a whole (one or several combined measurements) or on samples from an item. In the latter case a statistical method is used to evaluate whether the activity concentration is above or below the clearance level. The paper describes the different elements of the Clearance Function and the processing of items through the flow routes depending on the likely activity content and the distribution of activity. It is shown how uncertainties are incorporated in the clearance criteria. Experience from the first year of operation of the Clearance Function is reported. (author)

  17. An accredited infrastructure for clearance of decommissioning waste

    The nuclear research reactors and a hot-cell facility at the Riso site in Denmark have been closed and are in the process of being decommissioned. This has prompted the development of an accredited infrastructure called the Clearance Function. This function is responsible for the activity concentration measurements of the clearance candidates and for the demonstration of compliance with the clearance levels for the released objects. The Clearance Function comprises laboratory facilities, measuring equipment, measuring procedures, waste handling software, software for clearance related calculations and trained personnel. An accreditation of the Clearance Function has been granted from the accreditation body, DANAK, according to the international standard ISO/IEC 17025:2005. DANAK is a member of ILAC, the International Laboratory Accreditation Cooperation. The Clearance Function has been accredited to measure surface-specific and mass-specific activities using surface contamination monitors and high purity germanium detectors. The germanium detectors are characterised and in each measurement they are calibrated using the ISOCS calibration software. Activity concentration measurements can be made on items as a whole (one or several combined measurements) or on samples from an item. In the latter case a statistical method is used to evaluate whether the activity concentration is above or below the clearance level. The paper describes the different elements of the Clearance Function and the processing of items through the flow routes depending on the likely activity content and the distribution of activity. It is shown how uncertainties are incorporated in the clearance criteria. Experience from the first year of operation of the Clearance Function is reported. (author)

  18. Reforming Customs Clearance in Pakistan

    Ahmad, Manzoor

    2010-01-01

    Simple, fast, transparent customs clearance procedures encourage trade-and the resulting tariffs and related taxes raise government revenue and stimulate economic development. After outsourcing failed to make customs more efficient or increase revenue, in 2002 Pakistan began pursuing a modern single window system for customs clearance. In 2005 the system was introduced at the port of Karac...

  19. RATIONAL CUSTOMS CLEARANCE TECHNOLOGY CHOICE

    Shramenko, N.; Andriets, V.

    2008-01-01

    Issues concerning cargo delivery efficiencyincrease by choice of rational customs clearance technology have been considered. Three possible variants of customs clearance andmethods which allow to define the most rational version of cargo delivery in international road communication based on main efficiency criteria for definite distance have been presented.

  20. Analysis of conservativity analysis for clearance levels. Final report

    When deriving clearance levels for material from nuclear installations it is necessary to proceed with a certain degree of conservativity. This can, however, differ between various sets of clearance levels leading to inconsistencies between clearance pathways. The aim of the work therefore is to compare levels of conservativity for the following two sets of clearance levels: clearance levels for disposal as conventional waste and for metallic materials for recycling/reuse. A method was developed to quantify the degree of conservativity and make it comparable. The actual and future situation for disposal of (conventional) wastes in Germany was analysed. In addition, the masses, nuclide vectors, geographical distribution etc. for slightly radioactive material being cleared for conventional disposal was analysed and modelled and the resulting dose distributions were calculated. The values for the clearance levels were taken from the 1995 recommendation by the German Commission on Radiation Protection (SSK). By using realistic scenarios, the exposure was calculated for the personnel on the landfills and for persons of the general public being exposed via groundwater pathways. It could be shown that the trivial dose range will not be exceeded even if the masses of cleared material per landfill site exceed 100 Mg/a. Because of the types and distribution of nuclear installations in Germany and because of the nuclide vectors it is therefore not necessary to limit the masses per landfill sites. Clearance levels that are determined by the exposure pathways external exposure to and the inhalation of dust by the landfill personnel show a similar level of conservativity as those for metal scrap. This means that the clearance levels for gamma emitting nuclides are not overly restrictive. Although radiologically justified, raising the clearance levels would not lead to an increase of the material quantities because other nuclides of the respective nuclide vectors are limiting. In

  1. Antipyrene clearance in Indian villagers.

    Desai, N K; Sheth, U K; Mucklow, J C; Fraser, H S; Bulpitt, C J; Jones, S.W.; Dollery, C. T.

    1980-01-01

    1 Antipyrine clearance has been measured using saliva samples in 50 Maharashtrans from a village to the north of Bombay. 2 All subjects were very lean and were also anaemic probably as a result of hookworm infestation. 3 Antipyrine clearance was 36% faster than in White Londoners studied previously and more than twice as fast as in Asian immigrants living in London. 4 Clearance was 25% faster in men than in women but volume of distribution was also greater in men and mean half-lives did not d...

  2. Clearance of von Willebrand factor. : Clearance of von Willebrand factor

    Denis, Cécile; Christophe, Olivier; Oortwijn, Beatrijs,; Lenting, Peter,

    2008-01-01

    The life cycle of von Willebrand factor (VWF) comprises a number of distinct steps, ranging from the controlled expression of the VWF gene in endothelial cells and megakaryocytes to the removal of VWF from the circulation. The various aspects of VWF clearance have been the objects of intense research in the last few years, stimulated by observations that VWF clearance is a relatively common component of the pathogenesis of type 1 von Willebrand disease (VWD). Moreover, improving the survival ...

  3. Improved survival and renal prognosis of patients with type 2 diabetes and nephropathy with improved control of risk factors

    Andrésdóttir, Gudbjörg; Jensen, Majken; Carstensen, Bendix;

    2014-01-01

    become standard of care. RESEARCH DESIGN AND METHODS: All patients with type 2 diabetes and DN (n = 543) at the Steno Diabetes Center were followed during 2000-2010. GFR was measured yearly with 51Cr-EDTA plasma clearance. Annual decline in GFR was determined in patients with at least three measurements...... over a minimum of 3 years (∆GFR cohort, n = 286). Results were compared with historical data, obtained using identical criteria at our hospital, before implementation of current treatment guidelines. RESULTS: Baseline mean (SD) GFR was 74 (32) mL/min/1.73 m2. More than 93% received RAS inhibition...... onset of DN in the ∆GFR cohort was compared with that of our prior ∆GFR cohort from 1983 to 2003 (n = 227). Crude mortality risk was reduced by 42% and after age adjustment by 50% (P < 0.001 for both). In a multistate model accounting for competing risks of ESRD and death, prior cardiovascular disease...

  4. GFR prediction from cystatin C and creatinine in children: body cell mass increases accuracy of the estimate

    Andersen, Trine Borup; Jødal, Lars; Bøgsted, Martin;

    ) aged 2-14 years (mean 8.8 years). GFR was 14-147 mL/min/1.73m2 (mean 97 mL/min/1.73m2). BCM was estimated using bioimpedance spectroscopy (Xitron Hydra 4200). Log-transformed data on BCM/CysC, serum creatinine (SCr), body-surface-area (BSA), height x BSA/SCr, serum CysC, weight, sex, age, height, serum......AIM: To derive an accurate prediction model for estimating glomerular filtration rate (GFR) in children based primarily on the endogenous renal function marker cystatin C (CysC) and body cell mass (BCM). THEORY: Cystatin C is produced at a constant rate in all cells of the body and is excreted by...... glomerular filtration followed by catabolization in the tubular cells. We hypothesized that production rate is proportional to body cell mass (BCM) and inferred GFR (mL/min) to be proportional to BCM/CysC. MATERIAL AND METHODS: GFR was determined with 51Cr-EDTA-clearance in 131 children (52 girls, 79 boys...

  5. Detecting reduced renal function in children

    Andersen, Trine Borup; Jødal, Lars; Erlandsen, Erland J;

    2013-01-01

    using two cut-off levels, dividing renal function into normal or reduced, with an intermediate "gray zone" of indeterminable results.Methods Glomerular filtration rate was measured by plasma clearance of 51Cr-EDTA (13.7–147.4 mL/min/1.73 m2) in 119 children (age range 2.3–14.9 years).Reduced renal...... function was defined as a GFR of<82 mL/min/1.73 m2. SCr, SCysC, age-normalized creatinine (SCr-ratio), and eight published GFR-models were compared for their ability to correctly classify renal function as normal or reduced. Cut-off levels were determined so as to give 99 % certainty outside the gray zone.......Results The multivariable GFR-models by Schwartz et al. (J Am Soc Nephrol 2009; 20:629–637) and Zappitelli et al. (Am J Kidney Dis 2006; 48:221–230) and two models by Andersen et al. [Am J Kidney Dis 2012; 59(1):50–57: body cell mass (BCM)-model and Weight-model] performed significantly better than all other...

  6. Prediction of renal function (GFR) from cystatin C and creatinine in children: Body cell mass increases accuracy of the estimate

    Andersen, Trine Borup; Jødal, Lars; Bøgsted, Martin;

    ) aged 2-14 years (mean 8.8 years). GFR was 14-147 mL/min/1.73m2 (mean 97 mL/min/1.73m2). BCM was estimated using bioimpedance spectroscopy (Xitron Hydra 4200). Log-transformed data on BCM/CysC, serum creatinine (SCr), body-surface-area (BSA), height x BSA/SCr, serum CysC, weight, sex, age, height, serum......AIM: To derive an accurate prediction model for estimating glomerular filtration rate (GFR) in children based primarily on the endogenous renal function marker cystatin C (CysC) and body cell mass (BCM). THEORY: Cystatin C is produced at a constant rate in all cells of the body and is excreted by...... glomerular filtration followed by catabolization in the tubular cells. We hypothesized that production rate is proportional to body cell mass (BCM) and inferred GFR (mL/min) to be proportional to BCM/CysC. MATERIAL AND METHODS: GFR was determined with 51Cr-EDTA-clearance in 131 children (52 girls, 79 boys...

  7. Large kidneys predict poor renal outcome in subjects with diabetes and chronic kidney disease

    Vendrely Benoit

    2010-03-01

    Full Text Available Abstract Background Renal hypertrophy occurs early in diabetic nephropathy, its later value is unknown. Do large kidneys still predict poor outcome in patients with diabetes and Chronic Kidney Disease (CKD? Methods Seventy-five patients with diabetes and CKD according to a Glomerular Filtration Rate (GFR, by 51Cr-EDTA clearance below 60 mL/min/1.73 m2 or an Albumin Excretion Rate above 30 mg/24 H, had an ultrasound imaging of the kidneys and were cooperatively followed during five years by the Diabetology and Nephrology departments of the Centre Hospitalier Universitaire de Bordeaux. Results The patients were mainly men (44/75, aged 62 ± 13 yrs, with long-standing diabetes (duration:17 ± 9 yrs, 55/75 type 2, and CKD: initial GFR: 56.5 (8.5-209 mL/min/1.73 m2, AER: 196 (20-2358 mg/24 H. Their mean kidney lenght (108 ± 13 mm, 67-147 was correlated to the GFR (r = 0.23, p Conclusions Large kidneys still predict progression in advanced CKD complicating diabetes. In these patients, ultrasound imaging not only excludes obstructive renal disease, but also provides information on the progression of the renal disease.

  8. Renal function analysis by CT. CT clearance versus [sup 131]I-Hippuran clearance. Eine Nierenfunktionsanalyse durch die Computertomographie. CT-Clearance versus [sup 131]Jod-Hippuran-Clearance

    Kaltenborn, H.; Klose, K. (Johannes-Gutenberg-Universitaet Mainz, Radiologische Klinik (Germany))

    1992-06-01

    The CT clearance in a number of urological patients (39 patients, 25 with normal renal function) was studied by means of an ''area under curve'' (AUC) method, using a region of interest. 31 patients were given meglumine ioxithalamate and 8 patients Iopamidol as a contrast medium. Both for total and partial function there was highly significant correlation with isotope clearance with good reproducibility. The difference in the pharmacokinetics of the contrast media affected the absolute clearance values. (orig.).

  9. Lithium clearance in chronic nephropathy

    Kamper, A L; Holstein-Rathlou, N H; Leyssac, P P;

    1989-01-01

    1. Lithium clearance measurements were made in 72 patients with chronic nephropathy of different aetiology and moderate to severely reduced renal function. 2. Lithium clearance was strictly correlated with glomerular filtration rate, and there was no suggestion of distal tubular reabsorption of...... clearance data were independent of whether renal disease was of primarily glomerular or tubular origin and, further, were not influenced by long-term conventional antihypertensive treatment. 6. It is concluded that, even with a reduced kidney function, the data are compatible with the suggestion that...... lithium clearance may be a measure of the delivery of sodium and water from the renal proximal tubule. With this assumption it was found that adjustment of the sodium excretion in chronic nephropathy initially takes place in the distal parts of the nephron (loop of Henle, distal tubule and collecting duct...

  10. Measurement of nasal mucociliary clearance.

    Corbo, G M; Foresi, A; Bonfitto, P; Mugnano, A; Agabiti, N.; Cole, P J

    1989-01-01

    The saccharin test was carried out in a randomly selected sample of schoolchildren (142 boys and 153 girls, age range 11-14 years) to determine the variability and reproducibility of the test and to assess whether it could be used as a screening test for nasal mucociliary clearance. Nasal mucociliary clearance times were analysed according to clinical history (asthma, rhinitis, asthma with rhinitis, and acute upper respiratory tract infections), laboratory findings (positive skin test respons...

  11. Inherited Disorders of Bilirubin Clearance

    Memon, Naureen; Weinberger, Barry I; Hegyi, Thomas; Aleksunes, Lauren M

    2015-01-01

    Inherited disorders of hyperbilirubinemia may be caused by increased bilirubin production or decreased bilirubin clearance. Reduced hepatic bilirubin clearance can be due to defective 1) unconjugated bilirubin uptake and intrahepatic storage, 2) conjugation of glucuronic acid to bilirubin (e.g. Gilbert syndrome, Crigler-Najjar syndrome, Lucey-Driscoll syndrome, breast milk jaundice), 3) bilirubin excretion into bile (Dubin-Johnson syndrome), or 4) conjugated bilirubin re-uptake (Rotor syndrom...

  12. Distribution and clearance of radioactive aerosol on the nasal mucosa.

    McLean, J A; Bacon, J R; Mathews, K P; Thrall, J H; Banas, J M; Hedden, J; Bayne, N K

    1984-03-01

    The distribution and clearance of aerosolized radioactive technetium 99m pertechnate in physiologic buffered saline was analyzed in four human adult asymptomatic volunteers following delivery into one nostril in the same manner as for nasal challenge testing (i.e., 0.1 ml via a 251 DeVilbiss atomizer powered by a compressor delivering 0.10 +/- 0.01 gm/spray). For comparison, squeeze bottles and spray bottles from commercial sources, a 114 and a 127 DeVilbiss atomizer, and a pipette were employed. Lateral imagery via minicomputer processing was used to determine both distribution and clearance of the radiotracer. The counts after 1 minute were lower following pipette delivery than with the other devices. None yielded discernable , wide-spread distribution of aerosol throughout the nasal cavity. Following delivery from the 251 atomizer, mean clearance at 17 minutes was 60.0%. Similar clearance rates were obtained with the other spraying methods except for lower values with the squeeze bottle. Analysis of six hour clearance studies by linear regression showed a relatively rapid initial phase, which is probably due largely to mucociliary clearance, and a prolonged late phase related to the very slow disappearance of residual material located far anteriorly in the nose. Achieving good initial retention and rapid clearance of material deposited anteriorly in the nose are desirable attributes of devices employed for administering materials intranasally. PMID:6328631

  13. Comparison of renal clearance of 99mTc-DTPA and inulin 131I-hippurate and PAH as well as creatinine clearance in Wistar-rats

    Averages and standard deviations of 99mTc-DTPA and 131I-hippurate slope clearance were consecutively determined for 56 male Wistar rats, with a body-weight of 271 ± 69 g in a single investigation. Clearance of 99mTc-DTPA was 17.4 ± 3.4, that of 131I-hippurate was 34.3 ± 7.2 μl · s-1 per 100 g body weight. For 17 rats inulin and PAH clearances were determined after 3 days with the steady-state method with continuous infusion and 3-4 periods of urine collection. During the same periods endogeneous creatinine clearance was determined. 99mTc-DTPA slope clearance correlated well with inulin clearance, also the hippurate with the PAH clearance. The high values of the filtration fraction, calculated from radioisotope and chemical methods, and the low PAH extraction of 42% lead to the conclusion, that PAH and hippurate are incompletely eliminated by the rat kidney from plasma and therefore are inadequate for determining renal blood flow in rats. Creatinine clearance was 4.7 ± 1.38 μl · s-1 per 100 g body weight, much lower than that of inulin and 99mTc-DTPA. Therefore is assumed, that tubular reabsorption of creatinine occurs and creatinine clearance cannot serve for the evaluation of GFR in rats. For this, however, the clearance of 99mTc-DTPA seems well applicable in Wistar rats. (author)

  14. Nasal mucociliary clearance in coal mine workers

    Cinar, F.; Beder, L. [Karaelmas University, Kozlu Zonguldak (Turkey)

    2004-06-01

    The purpose of this study was to analyze the effect of coal dust particles on nasal mucociliary function in coal mine workers. Using the saccharin method, nasal mucociliary clearance was determined for 77 subjects, of which 39 who worked in a coal mine were actively exposed to coal dust whereas 38 were unexposed control subjects. The measurements were performed in the coal mine, at the level of 170 m below sea level. The average saccharin nasal transit time in coal mine workers, 12.61 (SD: 4.30) minutes, is longer, than that of the control subjects, 10.97 (SD: 3.22). Although the findings of this study demonstrate that the coal particles affect the nasal mucociliary clearance, the difference in saccharin nasal transit time between the two groups (exposed vs unexposed) is not statistically significant (P = 0.063).

  15. Comparison of renal clearance of 99mTc-DTPA and inulin, 131I-hippurate and PAH as well as of the creatinine clearance in Wistar rats

    Order of magnitude and standard deviation of 99mTc-DTPA and 131I-hippurate slope clearance were analyzed successively in 56 male Wistar rats. The clearance of 99mTc-DTPA was 17.4 ± 3.43 μl · s-1 (100 g b-w)-1, of 131I-hippurate 34.3 ± 7.21 μl · s-1 (100 g b-w)-1. In 17 rats inulin and PAH clearances were analyzed by steady state method with permanent infusion and 3 to 4 urine collection periods 3 days later. The endogeneous creatinine clearance was determined within the same periods. The 99mTc-DTPA slope clearance corresponded to the inulin clearance, as well as the hippurate clearance to the PAH clearance. The high filtration fraction calculated from nuclear medicine and chemical clearance methods and the low PAH extraction (42%) let suggest that PAH and hippurate are eliminated only incompletely from plasma in rat kidney and are unsuitable for determination of renal blood supply in rats. The creatinine clearance with 4.7 ± 1.38 μl · s-1 (100 g b-w)-1 was far beneath the clearance of inulin and 99mTc-DTPA, supposing that creatinine is reabsorbed tubularly in part and the creatinine clearance can not be used for valuation of the GFR in rats. However, for this the 99mTc-DTPA clearance in Wistar rats seems to be well suited. (author)

  16. SKIN KINETICS AND DERMAL CLEARANCE

    Prakash Shashi

    2012-08-01

    Full Text Available Availability of several therapeutic and cosmetic formulations for topical application has made the research on skin kinetics as a topic of current interest. Topical formulations are typically meant for local effect although there is always a chance that the low molecular weight chemicals are easily transported across the skin layer and make it available in the systemic circulation. Thus there is a major concern about the transport of chemical moieties following the topical application of cosmetics and therapeutic formulations and the real time measurement of the molecules in the skin layer has become obligatory. It is well known that the properties of both drug and the excipients have identical role in determining the skin permeability of chemical moieties. In the last decade several investigations have been carried out in this filed using several in vitro and in vivo models. This review provides a brief account on the basics of skin kinetics, parameters assessed, various techniques and methods adapted in skin kinetic studies. Moreover, we have also discussed about the micro-environment inside the skin layer and the possible mechanism of drug depot formation, skin metabolism and clearance of molecules from the skin layers.

  17. The renal handling of sodium and water is not affected by the standard-dose cisplatin treatment for testicular cancer

    Daugaard, G; Strandgaard, S; Holstein-Rathlou, N H;

    1987-01-01

    Renal clearances of 51Cr-EDTA, lithium, sodium and potassium were measured before and after each of four consecutive treatment series with cisplatin in 15 men with testicular cancer. Since lithium is reabsorbed like sodium and water in the proximal tubules, but not reabsorbed to any measurable...... all other parameters of glomerular filtration and renal sodium handling remained normal throughout the study (with the exception of a fall in fractional sodium excretion after the first treatment series). Plasma magnesium declined during all four treatment periods, signifying renal magnesium wasting....

  18. Pathogenesis and treatment of diabetic glomerulopathy

    Diabetic glomerulopathy is the consequence, at the glomerular level, of diabetes. Diagnosis is based on the association of proteinuria, arterial hypertension and an early reduction of glomerular filtration in a diabetic patient, generally insulin-dependent. Diabetic glomerulopathy is a complication of type I diabetes, which begins in childhood or adolescence, but can also be discovered in type II diabetes. A definite diagnosis requires histological evidences ; glomerular clearance measurements (125I-iodothalamate or 51Cr-EDTA) yield important information concerning glomerular filtration. The authors subsequently address pathogenesis and therapeutic regimens, and they report on the particularities of this condition in type II diabetes. (authors). 30 refs., 2 tabs

  19. [Bromsulphalein clearance in persons in occupational contact with pesticides].

    Mechkov, G; Petkova, V; Zakhariev, N

    1987-01-01

    In 46 persons (sprayers, disinfectors, technicians of the agricultural aviation) the bromsulphalein clearance is traced, during the active work season with pesticides, after the method of Caroly, Nys and Alliot. It is established, that the mean value of bromsulphalein clearance (8.91%) is lower than that of the referent group healthy persons (14.5%). In 14 (31.34%) of the examined the values of the clearance are under 10%. The changes of the last do not correlate closely to other indices of the liver function. As an explanation of the results the authors presuppose general pathogenetic relations between the metabolism of pesticides and of bromsulphalein in the liver cell, with inclusion of glutathione-S-transferase systems. The study allows to give a practical conclusion for the meaning of the bromsulphalein clearance and assessment of the pesticides effect in persons who are in professional contact with them. PMID:3441475

  20. Lithium clearance in chronic nephropathy

    Kamper, A L; Holstein-Rathlou, N H; Leyssac, P P;

    1989-01-01

    1. Lithium clearance measurements were made in 72 patients with chronic nephropathy of different aetiology and moderate to severely reduced renal function. 2. Lithium clearance was strictly correlated with glomerular filtration rate, and there was no suggestion of distal tubular reabsorption of...... lithium or influence of osmotic diuresis. 3. Fractional reabsorption of lithium was reduced in most patients with glomerular filtration rates below 25 ml/min. 4. Calculated fractional distal reabsorption of sodium was reduced in most patients with glomerular filtration rates below 50 ml/min. 5. Lithium...... lithium clearance may be a measure of the delivery of sodium and water from the renal proximal tubule. With this assumption it was found that adjustment of the sodium excretion in chronic nephropathy initially takes place in the distal parts of the nephron (loop of Henle, distal tubule and collecting duct...

  1. Lactate clearance in cardiorespiratory emergency

    Serena Greco

    2007-08-01

    Full Text Available Early goal directed therapy has been found to improve prognosis in septic patients, if the therapeutic goal is achieved within the first six hours. The aim of our study is to demonstrate that in patients with acute cardiorespiratory failure, rapid (within 2 hours lactate clearance can help define patients’ prognosis. 67 consecutive patients, admitted to our 16-bed Emergency Medicine ward for acute cardiorespiratory failure (age 75,9 ± 9,8 (APACHE II score 19,0 ± 4,1, were included in the study. Blood lactate concentration was read at admission and after 2, 6 and 24 hours. We evaluated mortality at seven days and the use of orotracheal intubation (patients with negative outcome vs. discharge or transfer to a non-emergency ward with subsequent discharge (patients with negative outcome. Lactate concentration at admission was 4,6 ± 2,5 mmol/l; lactate clearance (% at 2 hours was 40,4 ± 32,1 in patients with a positive outcome and –8,3 ± 5,0 in patients with a negative outcome (p < 0,05. Lactate clearance at 2 hours < 25% is correlated to a negative outcome with an 84,2% sensitivity and a 79,2% specificity. The positive predictive value was 61,5% and the negative predictive value was 92,2%. Systematic lactate clearance monitoring can be used in cases of acute cardiorespiratory insufficiency to identify patients with a high risk of negative outcome. In our study, low clearance at two hours was associated with an increase in mortality and/or the need for orotracheal intubation. Conversely, a clearance at two hours of > 25% in most cases confirms the therapeutic strategy undertaken. Serial evaluation of blood lactate concentration may therefore be useful in guiding treatment strategies.

  2. Inherited Disorders of Bilirubin Clearance

    Memon, Naureen; Weinberger, Barry I; Hegyi, Thomas; Aleksunes, Lauren M

    2016-01-01

    Inherited disorders of hyperbilirubinemia may be caused by increased bilirubin production or decreased bilirubin clearance. Reduced hepatic bilirubin clearance can be due to defective 1) unconjugated bilirubin uptake and intrahepatic storage, 2) conjugation of glucuronic acid to bilirubin (e.g. Gilbert syndrome, Crigler-Najjar syndrome, Lucey-Driscoll syndrome, breast milk jaundice), 3) bilirubin excretion into bile (Dubin-Johnson syndrome), or 4) conjugated bilirubin re-uptake (Rotor syndrome). In this review, the molecular mechanisms and clinical manifestations of these conditions are described, as well as current approaches to diagnosis and therapy. PMID:26595536

  3. Application of clearance automatic laser inspection system to clearance measurement of concrete waste

    Recently, the Clearance Automatic Laser Inspection System (CLALIS) has been developed for the clearance measurement of metal scraps. It utilizes three-dimensional (3D) laser scanning, y-ray measurement and Monte Carlo calculation, and has outstanding detection ability. For the clearance measurement of concrete segments, the effect of background (BG) gamma rays from natural radionuclides in the measurement target, such as K-40 and the radioactive decay products of Th-232 and U-238, should be compensated for to ensure adequate waste management. Since NE102A plastic scintillation detectors are used for y-ray measurement in CLALIS, it is impossible to distinguish between count rates of natural radionuclides and contaminants on the basis of gamma-ray energy information. To apply CLALIS to the clearance measurement of concrete segments, the original activity evaluation method was improved by adding a new compensation procedure. In this procedure, BG count rate due to natural radionuclides is estimated by a Monte Carlo calculation with pre-analyzed data of a representative sample of the measurement target. The activity concentration of natural radionuclides in concrete differs markedly depending on the production location of its components, such as cement and aggregates. In this study, using six mock concrete waste samples, which were composed of cement and fine aggregate from various production locations, the accuracy of BG compensation was experimentally estimated. In addition, the accuracy of calibration for concrete waste was also estimated using a number of mock concrete segments of small and large triangular prisms. By considering the uncertainties of BG compensation and calibration, the detection limit of CLALIS for concrete waste was estimated. As a result, it was revealed that CLALIS could be applied to the clearance measurement of concrete segments when the mass of the measurement target is greater than approximately 1.1 kg and the key radionuclide is Co-60

  4. The optimal clearance design of micro-punching die

    K.S. Lee

    2008-07-01

    Full Text Available Purpose: The purpose of this research paper is focused on the optimal clearance design of micro-punching die by abductive network and SA method.Design/methodology/approach: The punching data (input and wear size (output were collected for a training database. In order to select proper clearance to evaluate the wear of die, the abductive network was used to establish an efficient relationship between input parameters and output result. This can help to predict wear size under any degree of clearance and hence to replace worn punches and dies at the right time. A simulated annealing (SA optimization algorithm with a performance index is then applied to the neural network for searching the optimal clearance parameters, and obtains rather satisfactory result as compared with the corresponding experiment verification.Findings: This study aims to identify the relationship between clearance and service life of micro punches using the Neural Network, and to find relational data involving the service life of punches and punching parameters in non-metal blanking processes. The result can be used to estimate optimal clearance between punch and die for industrial applications.Research limitations/implications: In this study, the practical punching processes with different punching conditions were carried out for a set of training data. A trained model exhibited a relationship between service life and clearance of micro punch and die through an abductive network system. The predicted value of wear by abductive network is very close to the actual experimental value, with an error of less than 8%. This result satisfies the required standard for IC factory production.Originality/value: A good clearance design not only increases the quality of product manufactured, but also reduces product’s burr. As a result, the wear of punches and dies can be greatly reduced and the life expectancy of punching dies increased.

  5. Experimental study on fluid flow in arciform clearance

    邵俊鹏; 汤卉; 贾慧娟

    2002-01-01

    The system damping and dynamic characteristics can be further improved by properly increasing thedamping coefficient ξh. For a special hydraulic damping structure, an arciform damping clearance often used inFCS, a mathematical model has been established for fluid flow using the theory of laminar flow in the clearanceof parallel plates. Analytical calculations are made for fluid flow in the arciform clearance and relational expres-sion is deduced for flow rate along the arciform cleaance height, pressure difference, maximum arciform clear-ance height, the flow rate for the fluid flow in arciform clearance as well, and its simplified formula is obtainedby using the theory of hydrodynamics and the curve - fitting method. This paper consists of two sections: the firstsection focuses on the theoretical analysis by using the simplified mathematical model and the second sectionmainly describes experimental analysis. The simplified formula is corrected with experimental results by consid-erig various boundary conditions of the damping clearance. Experimental results show that this study of arciformdamping clearance is reliable and practical.

  6. Determination of glomerular filtration rate from plasma clearance with Tc99m.DTPA by single; two and multi-sample methods

    Background.The plasma sample method following a single injection of radioactive markers has been proved to be simple and accurate for the determination of glomerular filtration rate (GFR) in clinical practice. The aim of this study was to assess clinical accuracy of single-, two-and multi-sample methods. Patients and Methods. The study was performed on 50 patients with various degrees of renal dysfunction (29 males and 21 females; aged 27-90 years). As a reference the true GFR was determined by means of the two compartment model curve fitting 10 plasma following a single-injection of Tc99m-DTPA. The GFR was estimated by the three methods of single-, two and multi-sample between 75 and 300 min after the injection. The GFR by two and multi-sample methods was determined with the slope and intercept algorithm and its overestimation was corrected by Brochner-Mortensen's formula. Results. In all patients with a GFR between 12 and 169 ml/min/1.73m2, accuracy for the determination of GFR was identical in both the single-and five-sample methods. In 46 patients with a GFR higher than 30 ml/min/1.73m2, the single-sample method exhibited the lowest standard error of mean of difference in GFR. In 38 patients with a GFR lower than 120 ml/min/1.732, the two and five sample methods were more accurate than the single-sample one. The best combination of sampling time for the two samples was 120 min and 240 min after the injection. Conclusion. Accuracy of each plasma sample method depends on the preserved GFR. As a matter of practice, the single-sample method is the first choice for a patient who is expected to have a GFR higher than 30 ml/min/1.73m2. The two-sample method is indicated only in a patient with severe renal failure with a GFE lower than 30 ml/min/1.73m2 (au)

  7. 14 CFR 25.925 - Propeller clearance.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller clearance. 25.925 Section 25.925 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated,...

  8. 32 CFR 154.48 - Issuing clearance.

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Issuing clearance. 154.48 Section 154.48 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE SECURITY DEPARTMENT OF DEFENSE PERSONNEL SECURITY PROGRAM REGULATION Issuing Clearance and Granting Access § 154.48 Issuing clearance. (a) Authorities designated in paragraph...

  9. 30 CFR 56.11010 - Stairstep clearance.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stairstep clearance. 56.11010 Section 56.11010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Travelways § 56.11010 Stairstep clearance. Vertical clearance...

  10. 49 CFR 192.325 - Underground clearance.

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Underground clearance. 192.325 Section 192.325... Lines and Mains § 192.325 Underground clearance. (a) Each transmission line must be installed with at least 12 inches (305 millimeters) of clearance from any other underground structure not associated...

  11. Vest Chest Physiotherapy Airway Clearance is Associated with Nitric Oxide Metabolism

    Sisson, Joseph H.; Wyatt, Todd A.; Pavlik, Jacqueline A.; Pawanjit S. Sarna; Murphy, Peter J

    2013-01-01

    Background. Vest chest physiotherapy (VCPT) enhances airway clearance in cystic fibrosis (CF) by an unknown mechanism. Because cilia are sensitive to nitric oxide (NO), we hypothesized that VCPT enhances clearance by changing NO metabolism. Methods. Both normal subjects and stable CF subjects had pre- and post-VCPT airway clearance assessed using nasal saccharin transit time (NSTT) followed by a collection of exhaled breath condensate (EBC) analyzed for NO metabolites (NO x ). Results. VCPT s...

  12. 76 FR 47917 - Lead; Clearance and Clearance Testing Requirements for the Renovation, Repair, and Painting Program

    2011-08-05

    ... August 5, 2011 Part IV Environmental Protection Agency 40 CFR Part 745 Lead; Clearance and Clearance... AGENCY 40 CFR Part 745 RIN 2070-AJ57 Lead; Clearance and Clearance Testing Requirements for the... 2008 Lead Renovation, Repair, and Painting Program (RRP) rule, the EPA agreed to propose a number...

  13. Measurement of single kidney contrast media clearance by multiphasic spiral computed tomography: preliminary results

    Objective. We present preliminary results of a new method (hereinafter called 'CT-clearance') to measure single kidney contrast media clearance by performing multiphasic helical CT of the kidneys. CT-clearance was calculated according to an extension of the Patlak-Plot. In contrast to prior investigators, who repeatedly measured a single slice, this method makes it possible to calculate single kidney clearance from at least three spiral CTs, utilizing the whole kidney volume. Methods. Spiral CT of the kidneys was performed unenhanced and about 30 and 100 s after administration of about 120 ml iopromide. Sum-density of the whole kidneys and aortic density was calculated from this data. Using this data, renal clearance of contrast media was calculated by CT-clearance in 29 patients. As reference, Serum-clearance was calculated in 24 patients by application of a modified one-exponential slope model. Information on the relative kidney function was gained by renal scintigraphy with Tc99m-MAG-3 or Tc99m-DMSA in 29 patients. Results. Linear regression analysis revealed a correlation coefficient of CT-clearance with Serum-clearance of r=0.78 with Cl (CT) [ml/min]=22.2+1.03 * Cl (serum), n=24. Linear regression of the relative kidney function (rkf) of the right kidney calculated by CT-clearance compared to scintigraphy results provided a correlation coefficient r=0.89 with rkf(CT)[%]=18.6+0.58 * rkf(scintigraphy), n=29. Conclusion. The obtained results of contrast media clearance measured by CT-clearance are in the physiological range of the parameter. Future studies should be performed to improve the methodology with the aim of higher accuracy. More specifically, better determination of the aortic density curve might improve the accuracy

  14. Impaired tracheobronchial clearance in bronchiectasis.

    Currie, D C; Pavia, D; Agnew, J E; Lopez-Vidriero, M T; Diamond, P D; Cole, P J; Clarke, S. W.

    1987-01-01

    Tracheobronchial clearance was measured by a radioaerosol technique in 12 patients with bronchiectasis, seven patients with chronic obstructive lung disease expectorating mucoid sputum daily (group X), eight patients with chronic obstructive lung disease but negligible sputum expectoration (group Y), and 10 healthy subjects. The patients with bronchiectasis all expectorated purulent sputum daily (mean wet weight 47 g/day), had reduced forced expiratory volume in one second (FEV1) (mean 47.5% ...

  15. Age-dependence and intersubject variability of tracheobronchial particle clearance

    Robert Sturm

    2011-01-01

    Full Text Available SUMMARY.Background: The detailed study of tracheobronchial clearanceof inhaled particles represents one of the basic research questionsin lung medicine. The clearance efficiency varies in different agegroups and between males and females.The differences can bepartly clarified by the application of a well validated theoreticalapproach. This study applied a relevant model to children (1 year,5 years, 10 years, juveniles (15 years, and adults of different ages(18, 21, 25, 34, 50, and 60 years and to both sexes. Methods: Themathematical model used for clearance simulation is based on theconcept of a stochastic lung structure and considers both early fastmucociliary clearance and a later, slow clearance fraction, fs, effectedby particular uptake by tracheobronchial cells, e.g., macrophagesand epithelial cells. According to this model, the calculated mucusvelocities for each airway generation of the tracheobronchial compartmentare normalized to a respective tracheal mucus velocitythat is estimated for each of the age groups studied from an allometricfunction. Results: In general, tracheobronchial clearanceefficiency undergoes a significant increase from childhood to youngadulthood, reaching a maximum at 25-30 years and decreasingagain from about 30 years to 60 years. Conversely to the improvementof clearance, the continuous change of airway morphometrywith increasing age causes a decrease of the filtering effect in thetrachea and main bronchi, which is of marked importance in infants.The modelling results demonstrate differences in tracheobronchialclearance between males and females, generally in the range from0 to 5%, which are exclusively determined by the individual lunggeometry. Conclusions: Based on theoretical computations itcan be concluded that tracheobronchial clearance is a phenomenonthat depends on both age and sex. Biological studies are necessaryto determine the cellular and molecular mechanisms underlyingthe age-dependent development of

  16. Periodic response of multi-disk rotors with bearing clearances

    Kim, Y. B.; Noah, S. T.; Choi, Y. S.

    1991-02-01

    The forced steady state response of a multi-disk rotor system involving a clearance at one of the bearings is determined by using a harmonic balance approach. The impedance method is applied to each of the harmonic steady state components in order to reduce the system to its displacement at the non-linear bearing support. The results reveal the interrelated roles of the bearing clearance, mass eccentricity and side force in producing dangerous subharmonics. The significant effects of the strong non-linearity of a bearing clearance are studied as related to the various system parameters. The results show that the approach developed in this study is computationally superior to numerical integration methods in analyzing multi-disk rotor systems with strong non-linearity.

  17. Collimated in-situ gamma spectrometry: a new method for fast clearance measurements of large areas or building structures of nuclear facilities under decommissioning

    The ideas in the late sixties which led to the use of bare spectrometric radiation detectors like NaI(Tl), Ge(Li) or nowadays high-purity germanium detectors (wage) for field measurements (in-situ gamma spectrometry) were to get easy and rapid information about the radiological state of outdoor grounds after nuclear weapon tests or to estimate dose rates created by natural radioactive nuclides in the soil. In this cases, it was assumed, that there was no disturbance of the source-detector geometry for many hundred square meters around the detector. After the nuclear accident in Chernobyl in 1986 these advantages focussed strong scientific interest at the in-situ technique and in 1993 it was established in the German regulatory for immission surveillance after significant radioactive emissions. For unrestricted release in decommissioning 'in-situ gamma spectrometry may be the only method of achieving validation of the release criteria, particularly for large areas outside the buildings'. In a late phase of the decommissioning of a nuclear power plant all components containing a significant inventor of radioactivity are removed, leaving large surfaces with often poorly knows contamination levels. Taking in account only buildings of restricted areas in the next 50 years in Germany 7E3 Mg activated and 5E6 Mg contaminated concrete must be released from facilities under decommissioning. Before the ground and the building structures of the facility can be conventionally pulled down, the remaining radioactivity must be determined in order to check the radiological relevance of the concerned part of the plant and to decide the possible path of material release. The basis of assessment may be the so-called '10 μSv-concept'. (author)

  18. Development of the clearance level verification evaluation system. 2. Construction of the clearance data management system

    Clearance is defined as the removal of radioactive materials or radioactive objects within authorized practices from any further regulatory control by the regulatory body. In Japan, clearance level and a procedure for its verification has been introduced under the Laws and Regulations, and solid clearance wastes inspected by the national authority can be handled and recycled as normal wastes. The most prevalent type of wastes have generated from the dismantling of nuclear facilities, so the Japan Atomic Energy Agency (JAEA) has been developing the Clearance Level Verification Evaluation System (CLEVES) as a convenient tool. The Clearance Data Management System (CDMS), which is a part of CLEVES, has been developed to support measurement, evaluation, making and recording documents with clearance level verification. In addition, validation of the evaluation result of the CDMS was carried out by inputting the data of actual clearance activities in the JAEA. Clearance level verification is easily applied by using the CDMS for the clearance activities. (author)

  19. The influence of body posture on lithium clearance

    Kamper, A L; Strandgaard, S; Holstein-Rathlou, N H;

    1988-01-01

    fall in the sitting position, and fell significantly to 26 +/- 5 ml/min (p less than 0.025) in walking subjects. Absolute proximal tubular reabsorption rate of fluid correspondingly rose from 83 +/- 16 to 92 +/- 15 ml/min (p less than 0.005) and sodium clearance fell from 1.52 +/- 0.81 to 1.00 +/- 0...... during moderate physical activity. Hence, when renal tubular function is studied with the lithium clearance method, standardization of posture and physical activity is important. In such studies physical activity such as walking should particularly be avoided....

  20. The influence of body posture on lithium clearance

    Kamper, A L; Strandgaard, S; Holstein-Rathlou, N H; Munck, O; Leyssac, P P

    1988-01-01

    measured four times at 1-week intervals: two in the supine and one in the sitting position, and one when the subject was walking around. Glomerular filtration rate was not influenced by posture changes. On the contrary, lithium clearance, which in the supine position was 30 +/- 9 ml/min (1 SD), tended to...... during moderate physical activity. Hence, when renal tubular function is studied with the lithium clearance method, standardization of posture and physical activity is important. In such studies physical activity such as walking should particularly be avoided....

  1. Exploring the influential factors in incident clearance time: Disentangling causation from self-selection bias.

    Ding, Chuan; Ma, Xiaolei; Wang, Yinhai; Wang, Yunpeng

    2015-12-01

    Understanding the relationships between influential factors and incident clearance time is crucial to make effective countermeasures for incident management agencies. Although there have been a certain number of achievements on incident clearance time modeling, limited effort is made to investigate the relative role of incident response time and its self-selection in influencing the clearance time. To fill this gap, this study uses the endogenous switching model to explore the influential factors in incident clearance time, and aims to disentangle causation from self-selection bias caused by response process. Under the joint two-stage model framework, the binary probit model and switching regression model are formulated for both incident response time and clearance time, respectively. Based on the freeway incident data collected in Washington State, full information maximum likelihood (FIML) method is utilized to estimate the endogenous switching model parameters. Significant factors affecting incident response time and clearance time can be identified, including incident, temporal, geographical, environmental, traffic and operational attributes. The estimate results reveal the influential effects of incident, temporal, geographical, environmental, traffic and operational factors on incident response time and clearance time. In addition, the causality of incident response time itself and its self-selection correction on incident clearance time are found to be indispensable. These findings suggest that the causal effect of response time on incident clearance time will be overestimated if the self-selection bias is not considered. PMID:26373988

  2. Determination of Glomerular Filtration Rate with 51Cr, 58Co, 114mIn, 115mIn and 169Yb- Labelled EDTA and DTPA Complexes

    Some metal complexes are suitable for determination of the glomerular filtration rate (GFR). A series of labelled EDTA and DTPA complexes have been produced during the last two years by the Isotope Institute of the Hungarian Academy of Sciences. The common property of EDTA and DTPA complexes is their great stability, which is a major advantage over the iodinated compounds. We have demonstrated that none of the complexes used by us combine with plasma proteins or penetrate into the red blood cells. There is evidence that EDTA and DTPA leave the body exclusively by way of glomerular filtration. The results of more than 600 cases are presented. 169Yb EDTA was used in 315, 51Cr EDTA in 126, 114mIn EDTA in 83, 58Co DTPA in 72 and 115mIn EDTA in 28 cases for determination of GFR. The injected activity was 0.3 -4.0 μCi/kg body weight. In most cases the result has been compared with the 24-h endogenous creatine clearance, and in 50 cases with inulin clearance also. In general the single-shot method was used. Blood samples were taken about the first and the second hour after injection of the isotope. A formula is given for calculating GFR. In a few cases we administered the isotope in the same way as inulin (priming dose and constant plasma concentration sustained by an infusion pump). Our results show that the single-shot method is a very suitable one in routine clinical practice either in states of normal or reduced kidney function. Using the single-shot method for GFR determination is especially important in those cases where the collection of urine is impossible without using a catheter, which always entails the risk of infection. Results are reliable even in disorders of the urinary tract. During or after the procedure no side effects could be observed. (author)

  3. The role of neutrophilic mediators in acute inflammation of the gut

    Activation of granulocytes within the lamina propria by luminally derived bacterial products may represent an important mechanism in the pathogenesis of inflammatory bowel disease. One objective of this thesis was to determine the effects of luminal perfusion with N-formyl-methionyl-leucyl-phenylalanine (FMLP), a bacterial product that attracts and activates granulocytes, on mucosal permeability in different regions of the rat small intestine and colon. Mucosal permeability was measured using the blood-to-lumen clearance of 51Cr-EDTA during luminal perfusion with FMLP dissolved in Tyrode's solution. Of the bowel segments studied, mucosal permeability was significantly increased only in the distal 10 cm of the ileum. In order to define the role of neutrophilic oxidants in FMLP-induced ileitis, we evaluated the protective effect of several free radical scavengers and antioxidant enzymes. Pretreatment with the either superoxide dismutase or catalase had no effect on the FMLP-induced increase in mucosal permeability. However, treatment with either Mn-desferrioxamine, PZ51, desferrioxamine, or dimethylsulfoxide significantly attenuated FMLP-induced mucosal damage. Non-oxidative toxins released from activated neutrophil may be another mechanism by which FMLP increases mucosal permeability. In order to investigate the role of neutrophilic proteases in FMLP-induced ileitis, the effects of the nonspecific protease inhibitor soybean trypsin inhibitor, and the elastase inhibitors MeOSuc-Ala-Ala-Pro-Val-CH2Cl(MAAPV) and Eglin C on the FMLP-induced increases in 51Cr-EDTA clearance were determined

  4. 55Co-EDTA for renal imaging using positron emission tomography (PET): a feasibility study

    The feasibility of imaging renal function with 55Co-ethylene diamine tetraacetic acid (EDTA) and dynamic positron emission tomography was investigated. A group of normal Wistar rats was injected intravenously with 55Co-EDTA and underwent dynamic positron emission tomography (PET) imaging in order to study the biodistribution. The time-activity curves of the heart (blood pool), both kidneys, liver, and bladder were observed. In two animals, blood and urinary clearances of 55Co-EDTA were compared with those for 51Cr-EDTA. In one animal, unilateral reduction in kidney function was induced and the right/left ratio for the kidneys was determined. The time-activity curves showed that 55Co-EDTA cleared rapidly from the blood pool (heart), whereas prompt and high target-to-background ratios for both kidneys were obtained. The entire tracer was cleared from the renal parenchyma by urinary excretion and collection of the activity in the bladder. No specific activity uptake was noticed in any other organ or tissue. The clearances of 55Co-EDTA and 51Cr-EDTA in blood were not significantly different, showing that the nature of the M++ has no influence on the in vivo behavior of EDTA. 55Co can be produced easily by cyclotron irradiation and 55Co-EDTA is a promising physiological tracer for nephrological research using PET

  5. Kidney and lung injury in irradiated rats protected from acute death by partial-body shielding

    Ninety-six CD-1 male rats were exposed to gamma-ray doses (0-25 Gy) in increments of 5 Gy. One femur, the surgically exteriorized GI tract, and the oral cavity were shielded during irradiation to protect against acute mortality from injury to the hematopoietic system, small intestine, and oral cavity. In addition, the thoraxes of half of the animals from each dose group were shielded. At approximately monthly intervals from 2 to 10 months after irradiation the hematocrit, plasma urea nitrogen (PUN), and 51Cr-EDTA clearance were measured. During the study 20 thorax-shielded and 19 thorax-irradiated animals died. All rats whose thoraxes received 25 Gy irradiation and three out of seven rats whose thoraxes received 20 Gy died 1 to 3 months postirradiation with massive pleural fluid accumulation. Shielding the thoraxes prevented this mode of death at these doses. Kidney injury was judged to be the primary cause of death of all thorax-shielded animals and 15- and 20-Gy thorax-irradiated animals. Animals with kidney damage had elevated PUN and reduced 51Cr-EDTA clearance and hematocrits. The relative merits of each of these end points in assessing radiation-induced kidney injury after total-body exposure are discussed

  6. Lactate clearance in cardiorespiratory emergency

    Serena Greco; Giovanna Guiotto; Antonino Maffei; Stefania Martino; Giuseppe Romano; Fernando Schiraldi

    2007-01-01

    Early goal directed therapy has been found to improve prognosis in septic patients, if the therapeutic goal is achieved within the first six hours. The aim of our study is to demonstrate that in patients with acute cardiorespiratory failure, rapid (within 2 hours) lactate clearance can help define patients’ prognosis. 67 consecutive patients, admitted to our 16-bed Emergency Medicine ward for acute cardiorespiratory failure (age 75,9 ± 9,8) (APACHE II score 19,0 ± 4,1), we...

  7. Mucociliary and cough clearance as a biomarker for therapeutic development

    Bennett, William D; Daviskas, Evangelia; Hasani, Amir;

    2010-01-01

    A workshop/symposium on “Mucociliary and Cough Clearance (MCC/CC) as a Biomarker for Therapeutic Development” was held on October 21–22, 2008, in Research Triangle Park, NC, to discuss the methods for measurement of MCC/CC and how they may be optimized for assessing new therapies designed to...

  8. Mucociliary clearance, airway inflammation and nasal symptoms in urban motorcyclists

    Brant, Tereza C S; Yoshida, Carolina T; Tomas de S. Carvalho; Nicola, Marina L; Jocimar. A. Martins; Lays M. Braga; Regiani C. de Oliveira; Vilma Leyton; Carmen S. de André; Saldiva, Paulo H. N.; Rubin, Bruce K.; Naomi K. Nakagawa

    2014-01-01

    OBJECTIVES: There is evidence that outdoor workers exposed to high levels of air pollution exhibit airway inflammation and increased airway symptoms. We hypothesized that these workers would experience increased airway symptoms and decreased nasal mucociliary clearance associated with their exposure to air pollution. METHODS:...

  9. Mucociliary and cough clearance as a biomarker for therapeutic development

    Bennett, William D; Daviskas, Evangelia; Hasani, Amir;

    2010-01-01

    A workshop/symposium on “Mucociliary and Cough Clearance (MCC/CC) as a Biomarker for Therapeutic Development” was held on October 21–22, 2008, in Research Triangle Park, NC, to discuss the methods for measurement of MCC/CC and how they may be optimized for assessing new therapies designed to impr...

  10. The Clearance of Cyclosporine by Hemodialysis

    Venkataramanan, Raman; Ptachcinski, Richard J.; Burckart, Gilbert J.; YANG, SHIN L.; Starzl, Thomas E.; VAN THEIL, DAVID H.

    1984-01-01

    The pharmacokinetics of cyclosporine were studied in five liver transplant patients when they were on and off hemodialysis. There was no significant difference in the blood clearance of cyclosporine between these two periods. Less than 1 per cent of the dose of cyclosporine was recovered in the dialysate. The mean dialysis clearance was less than 1 ml/min. This represents less than 1 per cent of the total blood clearance of cyclosporine. Dosage alterations of cyclosporine during or after hemo...

  11. Revolute joints with clearance in multibody systems

    Flores, Paulo; Ambrósio, Jorge

    2004-01-01

    A computational methodology for dynamic analysis of multibody mechanical systems with joint clearance is presented in this work. Clearances always exist in real joints in order to ensure the correct relative motion between the connected bodies being the gap associated to them a result of machining tolerance, wear, and local deformations. Clearance at different joints is the source for impact forces, resulting in wear and tear of the joints, and consequently the degradation of the system perfo...

  12. Mucociliary clearance in early simple chronic bronchitis

    Tracheobronchial mucociliary clearance was measured in 37 patients with early simple chronic bronchitis. A non-invasive radio-aerosol technique with inhalation of 99Tcm labelled 5-μm polystyrene particles followed by assessment of radio-nuclide distribution by posterior gamma-camera scans was employed. The mucociliary clearance of the bronchitics was significantly slower than clearance of a non-smoker control group. An interim analysis of the effect of treatment with a surfactant stimulating drug, ambroxol, suggested a dosage-dependent tendency to a faster mucociliary clearance than seen in placebo-treated bronchitics. (author)

  13. Clearance of materials, buildings and land with low content of radioactive materials. Methodology and documentation

    The concepts and methods of clearance of materials originating from the decommissioning af the nuclear facilities at Risoe National Laboratory are described as well as procedures for clearance of buildings and land. The recommendations from international organisations as well as national regulation on clearance are presented. Methods for characterisation and separation of waste being candidate for clearance are presented.Di .erent methodologies for determining the content of radionuclides in candidate waste for clearance are discussed,and the need for and construction of a low-level laboratory for activity analyses in both bulky and less bulky subjects is described. Laboratory analyses, documentation of results and education of health physics personnel is presented. (au)

  14. Mucociliary clearance, airway inflammation and nasal symptoms in urban motorcyclists

    Tereza C.S. Brant

    2014-01-01

    Full Text Available OBJECTIVES: There is evidence that outdoor workers exposed to high levels of air pollution exhibit airway inflammation and increased airway symptoms. We hypothesized that these workers would experience increased airway symptoms and decreased nasal mucociliary clearance associated with their exposure to air pollution. METHODS: In total, 25 non-smoking commercial motorcyclists, aged 18-44 years, were included in this study. These drivers work 8-12 hours per day, 5 days per week, driving on urban streets. Nasal mucociliary clearance was measured by the saccharine transit test; airway acidification was measured by assessing the pH of exhaled breath condensate; and airway symptoms were measured by the Sino-nasal Outcome Test-20 questionnaire. To assess personal air pollution exposure, the subjects used a passive-diffusion nitrogen dioxide (NO2 concentration-monitoring system during the 14 days before each assessment. The associations between NO2 and the airway outcomes were analyzed using the Mann-Whitney test and the Chi-Square test. Clinicaltrials.gov: NCT01976039. RESULTS: Compared with clearance in healthy adult males, mucociliary clearance was decreased in 32% of the motorcyclists. Additionally, 64% of the motorcyclists had airway acidification and 92% experienced airway symptoms. The median personal NO2 exposure level was 75 mg/m3 for these subjects and a significant association was observed between NO2 and impaired mucociliary clearance (p = 0.036. CONCLUSION: Non-smoking commercial motorcyclists exhibit increased airway symptoms and airway acidification as well as decreased nasal mucociliary clearance, all of which are significantly associated with the amount of exposure to air pollution.

  15. Bronchoscintigraphy and pulmonary clearance of 99mTc-albumin colloid in study of mucociliary clearance

    A radioaerosol based method for measuring MC was introduced. It included an inhalation protocol that resulted in a predominant deposition of radioaerosol in the central bronchi and two simple procedures of evaluation: 1) a visual semi-quantitative bronchoscintigraphic analysis, and 2) a quantitative analysis of the retention of the radioactivity at different points after the inhalation. The results showed that bronchoscintigraphy was a simple technique that may be used to visualize a stimulation of mucociliary transport in the central airways of individuals that do not suffer from too much mucus hypersecretion. Comparison of the MC between individuals, however, should preferably be performed by the method of quantitative analysis of the radioactivity disappearance. A change of MC was found to be one of the first detectable effects on lung function of tobacco smoking. It could be effectively detected by measurement of radioaerosol clearance both by bronchoscintigraphy and simple quantification of the MC. The MC may be either acutely enhanced, reduced or not changed by smoking. Long-term smoking impairs MC. The enhancement of MC by β2-agonists was very limited in most patients with CF. In the hope of increasing mucus transport in patients with CF, these are treated with various chest physiotherapy techniques. The radioaerosol based method of measurement of MC could assess mucus clearance by chest physiotherapy and cough. (au)

  16. 14 CFR 23.925 - Propeller clearance.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller clearance. 23.925 Section 23.925 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless...

  17. 30 CFR 56.7018 - Hand clearance.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hand clearance. 56.7018 Section 56.7018 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7018 Hand clearance....

  18. Cortisol does not inhibit prednisolone clearance.

    Meffin, P J; Sallustio, B C; Purdie, Y J; Robson, R A; Wing, L M; Brooks, P M

    1985-01-01

    The disposition of prednisolone has been studied in eight male subjects with and without the concomitant administration of cortisol which produced plasma cortisol concentrations 10-fold higher than endogenous levels. The clearance and steady-state distribution volume of total prednisolone were increased as was the prednisolone free fraction but the clearance of unbound prednisolone was unaltered by cortisol co-administration.

  19. 30 CFR 56.11008 - Restricted clearance.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Restricted clearance. 56.11008 Section 56.11008 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Travelways § 56.11008 Restricted clearance. Where...

  20. 28 CFR 524.74 - Activities clearance.

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Activities clearance. 524.74 Section 524.74 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INMATE ADMISSION, CLASSIFICATION, AND TRANSFER CLASSIFICATION OF INMATES Central Inmate Monitoring (CIM) System § 524.74 Activities clearance. (a) Except as provided for in...

  1. Vest Chest Physiotherapy Airway Clearance is Associated with Nitric Oxide Metabolism

    Joseph H. Sisson

    2013-01-01

    Full Text Available Background. Vest chest physiotherapy (VCPT enhances airway clearance in cystic fibrosis (CF by an unknown mechanism. Because cilia are sensitive to nitric oxide (NO, we hypothesized that VCPT enhances clearance by changing NO metabolism. Methods. Both normal subjects and stable CF subjects had pre- and post-VCPT airway clearance assessed using nasal saccharin transit time (NSTT followed by a collection of exhaled breath condensate (EBC analyzed for NO metabolites (. Results. VCPT shorted NSTT by 35% in normal and stable CF subjects with no difference observed between the groups. EBC concentrations decreased 68% in control subjects after VCPT (before = 115 ± 32 μM versus after = 37 ± 17 μM; . CF subjects had a trend toward lower EBC . Conclusion. We found an association between VCPT-stimulated clearance and exhaled levels in human subjects. We speculate that VCPT stimulates clearance via increased NO metabolism.

  2. Effect of prior immobilization on muscular glucose clearance in resting and running rats

    In vitro studies have shown that prior disuse impairs the glucose clearance of red skeletal muscle because of a developed insensitivity to insulin. We studied whether an impaired glucose clearance is present in vivo in 42-h immobilized muscles of resting rats and, furthermore, whether the exercise-induced increase in glucose clearance of red muscles is affected by prior immobilization. The 2-[3H]deoxy-D-glucose (2DG) bolus injection method was used to determine glucose clearance of individual muscles. At rest, glucose clearance was markedly impaired in rats with previously immobilized red muscles compared with nonimmobilized control rats. During running, glucose clearance did not differ between muscles in previously immobilized and control rats. Insulin levels were always similar in the two groups and decreased during exercise. Intracellular nonphosphorylated 2DG was present in tissues with high glucose clearances. In conclusion, 42 h of immobilization markedly impairs glucose clearance of resting red muscle fibers in vivo. Apparently, physical inactivity in particular affects steps involved in insulin-mediated action that are not part of contraction-induced glucose uptake and metabolism. Presence of intracellular 2DG shows that separate determination of phosphorylated 2DG is necessary for accurate estimates of glucose metabolism and that accumulation of phosphorylated 2DG does not accurately reflect glucose transport

  3. Active generalized predictive control of turbine tip clearance for aero-engines

    Peng Kai; Fan Ding; Yang Fan; Fu Qiang; Li Yong

    2013-01-01

    Active control of turbine blade tip clearance continues to be a concern in design and con-trol of gas turbines. Ever increasing demands for improved efficiency and higher operating temper-atures require more stringent tolerances on turbine tip clearance. In this paper, a turbine tip clearance control apparatus and a model of turbine tip clearance are proposed;an implicit active generalized predictive control (GPC), with auto-regressive (AR) error modification and fuzzy adjustment on control horizon, is presented, as well as a quantitative analysis method of robust per-turbation radius of the system. The active clearance control (ACC) of aero-engine turbine tip clear-ance is evaluated in a lapse-rate take-off transient, along with the comparative and quantitative analysis of the stability and robustness of the active tip clearance control system. The results show that the resultant active tip clearance control system with the improved GPC has favorable steady-state and dynamic performance and benefits of increased efficiency, reduced specific fuel consump-tion, and additional service life.

  4. A pre- and postoperative study of split isotope clearance in childhood

    In 1978 43 patients have been operated in the Department of Pediatric Surgery, Krankenhaus Muenchen-Schwabing, because of recurrent urinary-tract infections with ureterovesical reflux or obstructive urinary-tract diseases. In all patients a split whole body clearance-study with a method modified after the method of Muehle with 131J-Hippuran was carried out pre- or postoperatively, respectively. In 78,5% of these cases the clearance-results were corresponding to the results of X-ray examination; 6 of the remaining patients had a worse clearance result and 3 had a better result than the X-ray findings would have suggested. (orig.)

  5. Numerical analysis of bump foil bearings without nominal radial clearance

    LIU Zhan-sheng; XU Huai-jin; ZHANG Guang-hui

    2008-01-01

    Bump foil bearings without nominal radial clearance were analyzed. An air film thickness model and a bearing theoretical analytical model were developed accounting for air compressibility and foil deformation. To analyze hydrodynamic characteristics of bump foil beatings with different operating eccentricities, the air film thickness equation and Reynolds equation were coupled through pressure and solved by Newton-Raphson Method(NRM) and Finite Difference Method (FDM). The characteristics of an bump foil bearing model were dis-cussed including load carrying capacity, film thickness and pressure distributions. The results of simulation show that bump foil beating without nominal radial clearance can provide better stability and greater load capaci-ty. This numerical analytical method also reveals a good convergence in numerical calculation.

  6. Radial Clearance Control and Internal Leakage Analysis of a Tri-Proportion Controller

    LI Dai-jin; ZHANG Yu-wen; TANG Hao; DANG Jian-jun; LUO Kai

    2009-01-01

    The tri-propellant thermal propulsion system is one of the hottest subjects in the.field of underwater vehicles recently. To improve efficiency of underwater vehicles, a method of radial clearance control of the tri-proportion has been proposed. Based on analyzing the factors which influence the pressure decrease and leakage of the tri-proportion controller, a method is used for precision analysis and proportion adjustment by using the median optimizing theory. Analysis results show that accuracy of the proportion controller is dependent on all the leakage, while the leakage is decided by radial clearance and pressure; the leakage can be controlled effectively and the accuracy of the proportion can be improved with the radial clearance control method. The method of accuracy analysis and clearance control has value on the design of various hydraulic motors.

  7. Factors contributing to delay in parasite clearance in uncomplicated falciparum malaria in children

    Sijuade Abayomi

    2010-02-01

    Full Text Available Abstract Background Drug resistance in Plasmodium falciparum is common in many endemic and other settings but there is no clear recommendation on when to change therapy when there is delay in parasite clearance after initiation of therapy in African children. Methods The factors contributing to delay in parasite clearance, defined as a clearance time > 2 d, in falciparum malaria were characterized in 2,752 prospectively studied children treated with anti-malarial drugs between 1996 and 2008. Results 1,237 of 2,752 children (45% had delay in parasite clearance. Overall 211 children (17% with delay in clearance subsequently failed therapy and they constituted 72% of those who had drug failure, i.e., 211 of 291 children. The following were independent risk factors for delay in parasite clearance at enrolment: age less than or equal to 2 years (Adjusted odds ratio [AOR] = 2.13, 95% confidence interval [CI]1.44-3.15, P 50,000/ul (AOR = 2.21, 95% CI = 1.77-2.75, P 20000/μl a day after treatment began, were independent risk factors for delay in clearance. Non-artemisinin monotherapies were associated with delay in clearance and treatment failures, and in those treated with chloroquine or amodiaquine, with pfmdr 1/pfcrt mutants. Delay in clearance significantly increased gametocyte carriage (P Conclusion Delay in parasite clearance is multifactorial, is related to drug resistance and treatment failure in uncomplicated malaria and has implications for malaria control efforts in sub-Saharan Africa.

  8. Capillary permeability in adipose tissue

    Paaske, W P; Nielsen, S L

    1976-01-01

    A method for measurement of capillary permeability using external registration of gamma emitting isotopes after close arterial bolus injection was applied to the isolated inguinal fat pad in slightly fasting rabbits. An average extraction of 26 per cent for 51Cr-EDTA was found at a plasma flow of...... about 7 ml/100 g-min. This corresponds to a capillary diffusion capacity of 2.0 ml/100 g-min which is half the value reported for vasodilated skeletal muscle having approximately twice as great capillary surface area. Thus, adipose tissue has about the same capillary permeability during slight metabolic...

  9. Characterization and Clearance of m/s Sigyn

    M/s Sigyn was a 2044 ton ship that transported contaminated material between 1982 and 2013. Most of the transports were with spent nuclear fuel between Swedish nuclear power plants and the Swedish fuel repository, Clab. In addition to spent fuel, m/s Sigyn also transported big contaminated components, from nuclear power plants in Europe, to Studsvik for analysis or decontamination and melting. She also transported components from Swedish nuclear power plants to final disposal of short lived waste, SFR. Even though all transported items have been cleaned, checked and wrapped with plastics, some activity ended up as contamination onboard. In December 2013 it was decided that m/s Sigyn was subject for decommissioning due to her age. This Paper describes the method in which the activity onboard m/s Sigyn was characterized and clearance levels were calculated. This method for radiological characterization and clearance has recently been developed in Sweden, the method is efficient in that it does not need a big pre characterization survey. Only the nuclide distribution and history of the object, is needed to start the final survey. In the future there will be further development of the method, making it possible to reduce the number of measurements even more. This will further optimize the method and reduce the cost for final surveys and clearance. (authors)

  10. Influence of chronic dosing on theophylline clearance.

    Efthimiou, H; Morgan, D. J.; Ioannides-Demos, L; Raymond, K.; McLean, A. J.

    1984-01-01

    Theophylline clearance was studied in normal healthy volunteers before and after chronic oral dosing. Oral theophylline clearance showed a significant decrease (P less than 0.001) from 59.3 +/- 6.48 ml/min (mean +/- s.e. mean, n = 10) to 48.0 +/- 6.4 ml/min. Steady-state intravenous clearance decreased by 26 +/- 2% from 55.1 +/- 7.7 ml/min to 41.0 +/- 5.96 ml/min (mean +/- s.e. mean, n = 6; P less than 0.001) at constant steady-state intravenous test concentrations (mean 15.0 +/- 1.6 microgra...

  11. Nucleotide-mediated airway clearance.

    Schmid, Andreas; Clunes, Lucy A; Salathe, Mathias; Verdugo, Pedro; Dietl, Paul; Davis, C William; Tarran, Robert

    2011-01-01

    A thin layer of airway surface liquid (ASL) lines the entire surface of the lung and is the first point of contact between the lung and the environment. Surfactants contained within this layer are secreted in the alveolar region and are required to maintain a low surface tension and to prevent alveolar collapse. Mucins are secreted into the ASL throughout the respiratory tract and serve to intercept inhaled pathogens, allergens and toxins. Their removal by mucociliary clearance (MCC) is facilitated by cilia beating and hydration of the ASL by active ion transport. Throughout the lung, secretion, ion transport and cilia beating are under purinergic control. Pulmonary epithelia release ATP into the ASL which acts in an autocrine fashion on P2Y(2) (ATP) receptors. The enzymatic network describes in Chap. 2 then mounts a secondary wave of signaling by surface conversion of ATP into adenosine (ADO), which induces A(2B) (ADO) receptor-mediated responses. This chapter offers a comprehensive description of MCC and the extensive ramifications of the purinergic signaling network on pulmonary surfaces. PMID:21560046

  12. Kinetics of various sup(99m)Tc-Sn-pyrophosphate compounds in the rat. Pt. 1

    The kinetic data of two different sup(99m)Tc-Sn-pyrophosphate compounds (compound A and B) were evaluated in non-adult rats. Only compound A concentrated in bone. Both compounds dispersed rapidly in the intravascular as well as the extravascular space. The plasma protein bond of both compounds increased with time after injection and impaired both the renal clearance of both compounds and the bone clearance of compound A. The renal clearance of both compounds was somewhat above that of 51Cr-EDTA. It is concluded that compound A and B is mainly excreted by glomerular filtration. About one fourth of the glomerular filtrate of compound B is reabsorbed and accumulated by the tubular cells. (orig.)

  13. Pressure losses and flow field distortion induced by tip clearance of centrifugal and axial compressors

    Senoo, Yasutoshi

    1987-03-01

    The flow field near the tip of compressor rotor blades is distorted by leakage through the tip clearance and the performance of the compressor is deteriorated. The literature regarding the tip clearance of compressor blades consists of computational fluid mechanics and experimental studies on the flow field and the pressure loss. Empirical equations expressing the pressure loss and the efficiency drop are varied. They relate to the lift coefficient in different ways, depending upon the ways of understanding the mechanics of pressure losses. These methods are examined and compared. Also, a brief discussion is made on the optimum value of the tip clearance.

  14. Dual roles for hepatic lectin receptors in the clearance of chilled platelets

    Rumjantseva, Viktoria; Grewal, Prabhjit K; Wandall, Hans H;

    2009-01-01

    Rapid chilling causes glycoprotein-Ib (GPIb) receptors to cluster on blood platelets. Hepatic macrophage beta(2) integrin binding to beta-N-acetylglucosamine (beta-GlcNAc) residues in the clusters leads to rapid clearance of acutely chilled platelets after transfusion. Although capping the beta......-Morell receptor binding, become increasingly involved in platelet removal. Macrophages rapidly removed a large fraction of transfused platelets independent of their storage conditions. With prolonged platelet chilling, hepatocyte-dependent clearance further diminishes platelet recovery and survival after...... transfusion. Inhibition of chilled platelet clearance by both beta(2) integrin and Ashwell-Morell receptors may afford a potentially simple method for storing platelets in the cold....

  15. Compressor airfoil tip clearance optimization system

    Little, David A.; Pu, Zhengxiang

    2015-08-18

    A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary. During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.

  16. Clearance of germ granules in the soma

    Sugimoto, Asako

    2009-01-01

    Germ granules are ribonucleoprotein complexes specifically segregated into germ cell lineages in diverse organisms. Recent studies indicate that multiple mechanisms are involved in the clearance of germ granules and their components in somatic cells in Caenorhabditis elegans embryos.

  17. Glial K(+) Clearance and Cell Swelling

    Macaulay, Nanna; Zeuthen, Thomas

    2012-01-01

    space into the glial cell are debated. Although spatial buffer currents may occur, their quantitative contribution to K(+) clearance is uncertain. The concept of spatial buffering of K(+) precludes intracellular K(+) accumulation and is therefore (i) difficult to reconcile with the K(+) accumulation...... repeatedly observed in glial cells during K(+) clearance and (ii) incompatible with K(+)-dependent glial cell swelling. K(+) uptake into non-voltage clamped cultured glial cells is carried out by the Na(+)/K(+)-ATPase and the Na(+)/K(+)/Cl(-) cotransporter in combination. In brain slices and intact optic...... nerve, however, only the Na(+)/K(+)-ATPase has been demonstrated to be involved in stimulus-evoked K(+) clearance. The glial cell swelling associated with K(+) clearance is prevented under conditions that block the activity of the Na(+)/K(+)/Cl(-) cotransporter. The Na(+)/K(+)/Cl(-) cotransporter is...

  18. The curious world of apoptotic cell clearance

    Weitzman, Jonathan B

    2004-01-01

    Analysis of knockout mice has brought into question the previously proposed role of the phosphatidylserine receptor (Ptdsr) in the clearance of apoptotic cell corpses, and has suggested important functions in regulating differentiation and inflammation.

  19. Exclusion, exemption, clearance European Union approach

    The presentation overviews the following issues: Euratom Basic Safety Standards; administrative requirements; radiation protection of the population. Scope of the Standards: natural radiation sources; exclusion. Exemption; Clearance; Import of radioactive scrap metal

  20. Deposition of aerosols and bronchial clearance measurements

    A special inhalative device is described for reproducible deposition patterns of radioactive aerosols to measure mucociliary and tussive clearance and to evaluate the effect of drugs on the bronchial tree is described. Additive actions on mucus transport exist between β2-agonists and theophylline, but not incombination with inhalative quarternary ammonium compounds (ipatropium and oxitropium bromide). Mucolytics are generally less effective on mucociliary clearance than β2-agonists and theophylline, positive, negative and nonresponders are ofter seen due to the different viscoelastic properties of the mucus. Mucus transport is more than mucociliary clearance. Two-phase gas/liquid movement and coughing are also important transport mechanisms for bronchial mucus. Therefore, bronchodilators enhance mucus transport by increasing airway patency, which increases total and regional air flow and improves cough clearance. (orig.)

  1. Mucociliary clearance, airway inflammation and nasal symptoms in urban motorcyclists

    Brant, Tereza C S; Yoshida, Carolina T; de S. Carvalho, Tomas; Marina L. Nicola; Jocimar A. Martins; Lays M. Braga; de Oliveira, Regiani C; Leyton, Vilma; Carmen S. de André; Saldiva, Paulo H N; Rubin, Bruce K; Naomi K. Nakagawa

    2014-01-01

    OBJECTIVES: There is evidence that outdoor workers exposed to high levels of air pollution exhibit airway inflammation and increased airway symptoms. We hypothesized that these workers would experience increased airway symptoms and decreased nasal mucociliary clearance associated with their exposure to air pollution. METHODS: In total, 25 non-smoking commercial motorcyclists, aged 18-44 years, were included in this study. These drivers work 8-12 hours per day, 5 days per week, driving on urba...

  2. Blade by Blade Tip Clearance Measurement

    A. G. Sheard

    2011-01-01

    This paper describes a capacitance-based tip clearance measurement system which engineers have used in the most demanding turbine test applications. The capacitance probe has survived extended use in a major European gas turbine manufacturer's high-temperature demonstrator unit, where it functioned reliably at a turbine entry temperature in excess of 1800 degrees Kelvin. This paper explores blade by blade tip clearance measurement techniques and examines probe performance under laboratory con...

  3. Clearance of inhaled particles in ankylosing spondylitis.

    Farquhar, D R; Chamberlain, M. J.; McCain, G A; Morgan, W K

    1989-01-01

    Patients with ankylosing spondylitis may uncommonly develop apical fibrobullous lung disease, the cause of which is unknown. It is postulated here that rigidity of the thoracic cage leads to reduced apical clearance of inhaled particles and may thereby predispose to chronic infection. Deposition and clearance of inhaled technetium-99m sulphur colloid particles were studied in eight male patients with ankylosing spondylitis who had chest wall rigidity (mean (SD) chest expansion 1.8 (1.07) cm) ...

  4. Reduction of antipyrine clearance in psoriasis.

    Marsden, J R; Williams, F M; Keys, B; Rawlins, M D; Shuster, S

    1984-01-01

    Antipyrine clearance was determined in 41 psoriatics and age-sex matched controls, using sequential measurements of salivary concentration. Antipyrine clearance and elimination rate constant were less in psoriatics (P less than 0.05) and apparent volumes of distribution were similar. These differences were greater between female psoriatics and controls (P less than 0.025; P less than 0.05) and the differences between male psoriatics and controls were not significant. Correlation of simultaneo...

  5. Extreme contagion in global habitat clearance

    Boakes, Elizabeth H.; Mace, Georgina M; Philip J K McGowan; Fuller, Richard A.

    2009-01-01

    Habitat clearance remains the major cause of biodiversity loss, with consequences for ecosystem services and for people. In response to this, many global conservation schemes direct funds to regions with high rates of recent habitat destruction, though some also emphasize the conservation of remaining large tracts of intact habitat. If the pattern of habitat clearance is highly contagious, the latter approach will help prevent destructive processes gaining a foothold in areas of contiguous in...

  6. Hemodialysis clearance of metronidazole and its metabolites.

    Lau, A. H.; Chang, C W; Sabatini, S

    1986-01-01

    Metronidazole is now being used with increasing frequency for various infectious conditions in patients with renal failure. It is commonly administered to septic patients who have developed acute renal failure requiring hemodialysis. The hemodialysis clearances of metronidazole and its metabolites were evaluated in nine renal failure patients on maintenance hemodialysis. The mean +/- standard deviation clearance and the extraction ratio were 106.9 +/- 16.3 ml/min and 0.65 +/- 0.08, respective...

  7. Modelling of Outer and Inner Film Oil Pressure for Floating Ring Bearing Clearance in Turbochargers

    Zhang Hao; Shi Zhanqun; Gu Fengshou; Ball, Andrew, E-mail: h.zhang3@hud.ac.uk [University of Huddersfield, Huddersfield, HD1 3DH (United Kingdom)

    2011-07-19

    Floating ring bearing is widely used in turbochargers to undertake the extreme condition of high rotating speed and high operating temperature. It is also the most concerned by the designers and users alike due to its high failure rate and high maintenance cost. Any little clearance change may result in oil leakage, which in turn cause blue smoke or black smoke according to leakage types. However, there is no condition monitoring of this bearing because it is almost impossible to measure the clearance especially the inner clearance, in which the inner oil film directly bears the high speed rotation. In stead of measuring clearance directly, this paper has proposed a method that uses film pressure as a measure to monitor the bearing clearance and its variation. A non-linear mathematical model is developed by using Reynolds equations with non-linear oil film pressure. A full description of the outer and inner film is provided along both axial and radial directions. A numerical simulation is immediately carried out. Variable clearance changes are investigated using the mathematical model. Results show the relationship between clearance and film pressure.

  8. Turbulent Heat Transfer of a Finned Plate in a Duct as Tip Clearance Changes

    Fins are employed to enhance the cooling performance of a system. There are a number of studies relevant to geometry of fins. Meanwhile, the studies relevant to tip clearance, have not performed enough, which is the distance between the tips of the fins and the wall. We investigated the optimal tip clearance, which maximizes the heat transfers by experimental and numerical analyses with wider range of ReDh than the previous studies. Turbulent heat transfers of a finned plate were measured. For an extended range of tip clearance and ReDh than other studies. A joint experimental and numerical analyses was performed to measure heat transfers. Mass transfer experiments using electroplating system was used and FLUENT 6.3.26 was used for the calculation. For the narrow tip clearances below 5 mm, were investigated by numerical method only. The bypass flow to the tip clearance region contributes to heat transfer area at the tip clearance region and does not contributes that of the fin region. Thus, the optimal tip clearance was founded and it exists vicinity of 0.2 mm

  9. Turbulent Heat Transfer of a Finned Plate in a Duct as Tip Clearance Changes

    Park, Hae-Kyun; Chung, Bum-Jin [Kyung Hee University, Yongin (Korea, Republic of)

    2015-05-15

    Fins are employed to enhance the cooling performance of a system. There are a number of studies relevant to geometry of fins. Meanwhile, the studies relevant to tip clearance, have not performed enough, which is the distance between the tips of the fins and the wall. We investigated the optimal tip clearance, which maximizes the heat transfers by experimental and numerical analyses with wider range of Re{sub Dh} than the previous studies. Turbulent heat transfers of a finned plate were measured. For an extended range of tip clearance and Re{sub Dh} than other studies. A joint experimental and numerical analyses was performed to measure heat transfers. Mass transfer experiments using electroplating system was used and FLUENT 6.3.26 was used for the calculation. For the narrow tip clearances below 5 mm, were investigated by numerical method only. The bypass flow to the tip clearance region contributes to heat transfer area at the tip clearance region and does not contributes that of the fin region. Thus, the optimal tip clearance was founded and it exists vicinity of 0.2 mm.

  10. Modelling of Outer and Inner Film Oil Pressure for Floating Ring Bearing Clearance in Turbochargers

    Zhang, Hao; Shi, Zhanqun; Gu, Fengshou; Ball, Andrew

    2011-07-01

    Floating ring bearing is widely used in turbochargers to undertake the extreme condition of high rotating speed and high operating temperature. It is also the most concerned by the designers and users alike due to its high failure rate and high maintenance cost. Any little clearance change may result in oil leakage, which in turn cause blue smoke or black smoke according to leakage types. However, there is no condition monitoring of this bearing because it is almost impossible to measure the clearance especially the inner clearance, in which the inner oil film directly bears the high speed rotation. In stead of measuring clearance directly, this paper has proposed a method that uses film pressure as a measure to monitor the bearing clearance and its variation. A non-linear mathematical model is developed by using Reynolds equations with non-linear oil film pressure. A full description of the outer and inner film is provided along both axial and radial directions. A numerical simulation is immediately carried out. Variable clearance changes are investigated using the mathematical model. Results show the relationship between clearance and film pressure.

  11. 19 CFR 4.61 - Requirements for clearance.

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Requirements for clearance. 4.61 Section 4.61 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY VESSELS IN FOREIGN AND DOMESTIC TRADES Foreign Clearances § 4.61 Requirements for clearance. (a) Application for clearance. A...

  12. 48 CFR 801.602-76 - Business clearance review.

    2010-10-01

    ... obtain a business clearance review prior to award of any contract, task or delivery order, or blanket... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Business clearance review... Authority, and Responsibilities 801.602-76 Business clearance review. (a) A business clearance review is...

  13. Effects and outcome of Tamsulosin more than just stone clearance after extracorporeal shock wave lithotripsy for renal calculi

    Objective: To determine the effect of Tamsulosin, as adjunctive medical therapy after Extracorporeal Shock Wave Lithotripsy for renal stones on rate of stone clearance, clearance time, pain intensity during stone clearance, steinstrasse formation and auxiliary surgical intervention required. Method: A prospective randomized controlled study was carried out in 120 patients who underwent ESWL for renal stones of 0.5-2.0 cm. They were randomized into study and control group in which Tamsulosin 0.4mg/day was given in former as an adjunctive medical therapy. All patients underwent ESWL every 2 weeks until complete stone clearance for 8 weeks. The parameters assessed were stone clearance, clearance time, pain intensity and effect on steinstrasse. Results: Of the 120 patients 60 were in each group. The stone clearance rate was greater in study than in control group, 58(96.7%) vs. 48(80%) respectively, (p<0.004). The mean stone clearance time was observed earlier in study group as compared to control group with significant statistical difference in stone size between 0.6-1.5 cm. The mean intensity of pain patients experienced according to Visual analogue scale (VAS) was significantly less in study group (p<0.002). The rate of steinstrasse formation was observed to be higher in control than in study group 15(25%) vs 6(10%) respectively(p<0.003), while its spontaneous clearance was higher in study group than in control group 83.3% vs 33.3% (p<0.03). Conclusion: Tamsulosin significantly increases stone clearance after shock wave lithotripsy for renal stones. It also appeared to facilitate earlier stone clearance, reduces severity of pain, reduces the incidence of steinstrasse formation and tends to facilitate its spontaneous clearance. (author)

  14. Preparation of iodine-125-labeled iothalamate for renal clearance measurements

    Iothalamate, a derivative of benzoic acid, is used as a contrast medium for renal function studies, particularly for measurement of glomerular filtration rate. Its chemical composition and clearance properties are similar to those of diatrizoate. The structural differences between these groups of iodinated benzoic acid derivatives are dependent on the groups attached at the 3- and 5-positions of 2,4,6-tri-iodobenzoic acid. The renal clearance of sodium iothalamate in humans closely approximates that of inulin, and it is used as a replacement for inulin in determining glomerular filtration rate. /sup 125/I-labeled iothalamate sodium can be prepared by the exchange-labeling method at pH 4.0. Iothalamate must first be isolated from the contrast medium preparation and purified before radioiodination. After radioiodination, the product is purified by means of precipitation and is then converted to the sodium salt

  15. Relationship of Insulin Sensitivity, Insulin Secretion, and Adiposity With Insulin Clearance in a Multiethnic Population

    Lorenzo, Carlos; Hanley, Anthony J.G.; Wagenknecht, Lynne E; Rewers, Marian J.; Stefanovski, Darko; Goodarzi, Mark O.; Haffner, Steven M

    2012-01-01

    OBJECTIVE We aimed to examine insulin clearance, a compensatory mechanism to changes in insulin sensitivity, across sex, race/ethnicity populations, and varying states of glucose tolerance. RESEARCH DESIGN AND METHODS We measured insulin sensitivity index (S I), acute insulin response (AIR), and metabolic clearance rate of insulin (MCRI) by the frequently sampled intravenous glucose tolerance test in 1,295 participants in the Insulin Resistance Atherosclerosis Study. RESULTS MCRI was positive...

  16. Clearance from the mouse brain by convection of interstitial fluid towards the ventricular system

    Bedussi, Beatrice; van Lier, Monique G. J. T. B.; Bartstra, Jonas W.; de Vos, Judith; Siebes, Maria; VanBavel, Ed; Bakker, Erik N.T.P.

    2015-01-01

    Background In the absence of a true lymphatic system in the brain parenchyma, alternative clearance pathways for excess fluid and waste products have been proposed. Suggested mechanisms for clearance implicate a role for brain interstitial and cerebrospinal fluids. However, the proposed direction of flow, the anatomical structures involved, and the driving forces are controversial. Methods To trace the distribution of interstitial and cerebrospinal fluid in the brain, and to identify the anat...

  17. Transient Proteolytic Modification of Mesenchymal Stromal Cells Increases Lung Clearance Rate and Targeting to Injured Tissue

    Kerkelä, Erja; Hakkarainen, Tanja; Mäkelä, Tuomas; Raki, Mari; Kambur, Oleg; Kilpinen, Lotta; Nikkilä, Janne; Lehtonen, Siri; Ritamo, Ilja; Pernu, Roni; Pietilä, Mika; Takalo, Reijo; Juvonen, Tatu; Bergström, Kim; Kalso, Eija

    2013-01-01

    This study showed that an alternative cell detachment of mesenchymal stromal/stem cells (MSCs) with pronase instead of trypsin significantly accelerated the lung clearance of the cells and, importantly, increased their targeting to an area of injury. Pronase detachment could be used as a method to improve the MSC lung clearance and targeting in vivo. This may have a major impact on the bioavailability of MSCs in future therapeutic regimes.

  18. Effect of Guide Vane Clearance Gap on Francis Turbine Performance

    Ravi Koirala

    2016-04-01

    Full Text Available Francis turbine guide vanes have pivoted support with external control mechanism, for conversion of pressure to kinetic energy and to direct them to runner vanes. This movement along the support is dependent on variation of load and flow (operating conditions. Small clearance gaps between facing plates and the upper and lower guide vane tips are available to aid this movement, through which leakage flow occurs. This secondary flow disturbs the main flow stream, resulting performance loss. Additionally, these increased horseshoe vortex, in presence of sand, when crosses through the gaps, both the surfaces are eroded. This causes further serious effect on performance and structural property by increasing gaps. This paper discusses the observation of the severity in hydropower plants and effect of clearance gaps on general performance of the Francis turbine through computational methods. It also relates the primary result with the empirical relation for leakage flow prediction. Additionally, a possible method to computationally estimate thickness depletion has also been presented. With increasing clearance gap, leakage increases, which lowers energy conversion and turbine efficiency along with larger secondary vortex.

  19. 75 FR 38959 - Lead; Clearance and Clearance Testing Requirements for the Renovation, Repair, and Painting...

    2010-07-07

    ... established in the Federal Register of May 6, 2010 (75 FR 25038) (FRL-8823-5). In that document, EPA proposed... AGENCY 40 CFR Part 745 RIN 2070-AJ57 Lead; Clearance and Clearance Testing Requirements for the... Federal Register of May 6, 2010, concerning several revisions to the 2008 Lead Renovation, Repair,...

  20. 75 FR 25037 - Lead; Clearance and Clearance Testing Requirements for the Renovation, Repair, and Painting Program

    2010-05-06

    ... Protection Agency 40 CFR Part 745 Lead; Clearance and Clearance Testing Requirements for the Renovation..., 2010 / Proposed Rules#0;#0; ] ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 745 RIN 2070-AJ57 Lead... 2008 Lead Renovation, Repair, and Painting Program (RRP) rule that established accreditation,...

  1. Technetium 99m mercaptoacetyltriglycine gamma camera clearance calculations: Methodological problems

    Major sources of errors in the gamma-camera methods for the calculation of renal clearance are the accuracy of background correction for obtaining the true renal time-activity curve and the validity of the externally recorded pre-cordial activity as an estimate of the plasmatic time-activity curve. With technetium 99m mercaptoacetyltriglycine (99mTc-MAG3), because of its high protein plasma binding, one could expect minimal extravascular diffusion and hence a more accurate externally detected plasmatic curve. The high extraction rate should reduce the influence of the background, but, on the other hand, the effect of hepatobiliary excretion on the calculation of renal clearance might be significant. Our results suggest that the hepatobiliary excretion of 99mTc-MAG3 does not influence the gamma-camera renal clearance determination, even in patients with low renal function. However, the pre-cordial curve does not reflect accurately the plasmatic disappearance curve; its calibration with a single plasma sample taken at the 20th min is responsible for significant errors, probably because of an unfavourable ratio between the intravascular and extravascular activities at the 20th min. (orig.)

  2. DOES BODY MASS INDEX INFLUENCE NASAL MUCOCILIARY CLEARANCE?

    Tamilselvan K, Latha R, Nirmala N, Susiganeshkumar E, Thananjayam A

    2015-01-01

    Full Text Available Background: The respiratory system is constantly exposed to particulate matter suspended in the inhaled air and one among the efficient mechanisms to trap and expel the particulate substances is the nasal and bronchial mucociliary clearance mechanism. This mucociliary clearance mechanism is influenced by both physiological and pathological factors that alter the functioning of the respiratory cilia and the overlying mucosal layer that traps the particulate agents. As Body mass index (BMI determines the health of a person by influencing various physiological parameters, this study has been planned to study the effect of normal and abnormal BMI (overweight and obese range on the nasal mucociliary clearance (NMC. Aim: To evaluate the effect of BMI on nasal mucociliary clearance (NMC. Materials & Methods: NMC was measured in 20 volunteers with normal BMI (18.5-22.9 Kg/m2 and 20 volunteers with BMI in overweight and obese range (23 Kg/m2 and above. The NMC time was recorded by the time the volunteers appreciated the sweet taste following the placement of ¼ of saccharin tablet (1mm x 1mm in the nostril referred as saccharin transit time (STT.Results: NMC was found to be prolonged in overweight and obese population and BMI has positive correlation with NMC as calculated by Pearson correlation with r value of 0.591 and p value 0.001 which is statistically significant. Conclusion: NMC time is prolonged in abnormal BMI referring to the impairment in the mucociliary escalator mechanism thus predisposing to disease states.

  3. Effect of high mannose glycan pairing on IgG antibody clearance.

    Liu, Yaoqing Diana; Flynn, Gregory C

    2016-05-01

    IgG antibodies contain N-linked glycans on the Fc portion of each heavy chain. The glycan on one heavy chain can either match the glycan on the other heavy chain (symmetrical pairing) or be different (asymmetrical pairing). These Fc glycans influence effector functions and can alter clearance rates. Previous studies showing that high mannose forms result in faster mAb clearance in humans were incapable of differentiating the impact of symmetrically vs. asymmetrically paired HM forms, and, therefore, the effect of pairing on clearance was not clear. Traditional analytical methods, which are used to measure glycans in such studies, do not determine the number of HM glycans per antibody. With a sensitive method designed to measure HM pairing, we followed the levels of symmetrically and asymmetrically paired HM on antibodies in human pharmacokinetic serum samples to determine the impact of Fc HM glycan pairing on therapeutic human IgG clearance in humans. The two HM paired forms cleared at the same rate, indicating that the effect on clearance was not proportional to the degree of modification. Since both forms can exist on therapeutic antibodies and the ratio can differ between products, measuring their relative levels is necessary to properly estimate effects on clearance. PMID:26992607

  4. Establishment and use of surgical rat models for assessment of organ specific in vivo clearance.

    Vestergaard, Bill

    2016-06-01

    models previously used as tools to investigate renal and hepatic clearance. An overview of the surgical procedures previously described for establishment of in vivo nephrectomy and hepatectomy models is given. Many different surgical methods have been employed in the attempt to make anephric or anhepatic in vivo models. The overall conclusion of the literature review was that a suitable clearance model would require only one surgical procedure. Furthermore, the clearance studies should be conducted immediately after completed surgery to decrease the impact on other clearance pathways and physiology in general. Paper II "The kidneys play an important role in the clearance of rFVIIa in rats" describes the establishment, validation and use of an in vivo model for assessment of renal clearance. The model employed was a rat nephrectomy model and the compounds investigated were inulin and rFVIIa. General physiology was assumed to be close to normal as rectal temperature, oxygen saturation and pulse were within normal range during the pharmacokinetic studies. Nephrectomy significantly reduced clearance of rFVIIa and almost completely abolished clearance of inulin. Thus, it was concluded that the nephrectomy model could be used in assessment of the relative importance of the kidneys in the clearance of rFVIIa and the data obtained indicate that renal clearance accounts for 50% of total body clearance of rFVIIa. Paper III "The kidneys play a central role in the clearance of rhGH in rats" addresses renal clearance of rhGH. The in vivo model established in Paper II was used in a pharmacokinetic study of rhGH to assess the relative importance of the kidneys in the clearance of rhGH. The conclusion drawn based on this study was that the kidneys account for 90% of total body clearance of rhGH in anaesthetized rats. Furthermore, it was noted that anaesthesia reduced clearance of rhGH by 36% compared to non-anaesthetized rats. In conclusion, establishment, validation and use of a rat

  5. Effect of metabolic regulation on renal leakiness to dextran molecules in short-term insulin-dependent diabetics

    Parving, H H; Rutili, F; Granath, K;

    1979-01-01

    were normalized within one to three weeks of effective insulin treatment. This rapid reversibility can hardly be explained by the previously demonstrated enlargement in glomerular size and filtration surface area, since these alterations remain unchanged after more than one month of insulin treatment......Renal clearance of dextran of two ranges of molecular size and glomerular filtration rate (GFR, 51Cr-EDTA) were measured in seven short-term insulin-dependent diabetics (mean age 25 years). Measurements were carried out in the same patient during good and poor metabolic regulation (plasma glucose....... The metabolic regulation did not influence the size-selective properties of the glomerular wall. Therefore, we suggest that the dominating mechanism involved in the GFR and renal dextran clearance alterations is functional, viz. increased filtration pressure....

  6. Atrial natriuretic peptide and renal adaptation to contralateral nephrectomy in healthy man

    Kamper, A L; Pedersen, E B; Strandgaard, S; Holstein-Rathlou, N H; Leyssac, P P; Skaarup, P; Hemmingsen, L; Holm, J; Munck, O

    1991-01-01

    adaptation to acute reduction in renal mass. Glomerular and tubular function was studied by measurements of the clearances of 51Cr-EDTA, lithium, sodium, potassium, and albumin. ANP was 7.4 +/- 3.1 pmol l-1 (mean +/- SD) before Nx and 8.7 +/- 6.1 pmol l-1 at 5 days after Nx and remained at this level through...... clearance had risen from 13 +/- 2 ml min-1 before Nx to 20 +/- 7 ml min-1 (p less than 0.01), and sodium and water balance was normal. To conclude, plasma ANP, AII, Aldo and AVP do not appear to be responsible for the hyperfiltration and depression of fractional proximal sodium and water reabsorption...... observed in recently uninephrectomized man with normal sodium and water balance....

  7. Short-term effects of liraglutide on kidney function and vasoactive hormones in type 2 diabetes

    Skov, J.; Pedersen, M.; Holst, Jens Juul;

    2016-01-01

    change local renal blood perfusion or oxygenation. The fractional excretion of lithium increased 14% (p = 0.01) and sodium clearance tended to increase (p = 0.06). Liraglutide increased diastolic and systolic blood pressure (3 and 6 mm Hg) and heart rate (3 min(-1) ) (all p < 0.05). Angiotensin II...... diabetes. Measurements included (51) Cr-EDTA plasma clearance estimated glomerular filtration rate (GFR) and MRI-based renal blood flow (RBF), tissue perfusion and - oxygenation. RESULTS: Liraglutide had no effect on GFR (95% CI -6.8 to 3.6 ml/min/1.73 m(2) ) or RBF (95% CI -39 to 30 ml/min) and did not...

  8. Studies on diphosphonate kinetics. Pt. 1

    To improve the understanding of diphosphonate affinity to metabolically active bone, the underlying diphosphonate kinetics have been evaluated and compared to Cr-EDTA kinetics. MDP binds to plasma proteins, varying from 25% initially to approximately 70% after 24 h. The renal clearance of diphosphonate is found to be equal to Cr-EDTA clearance. Using simultaneous bolus injection of 99Tc-MDP and 51Cr-EDTA, it has been possible to obtain a coarse estimate of bone uptake of MDP. This uptake is found to correlate well with s-alkaline phosphatase, but since MDP binding to bone is reversible, the plasma elimination curve is not monoexponential. Therefore it has not been possible to describe the uptake of MDP in bone mathematically. (orig.)

  9. Clearance Laboratory - Capability and measurement sensitivity

    A new low-level Clearance Laboratory has been built at the Risoe-site. Building materials with a low content of naturally occurring radionuclides have been used. To minimize transport of radon gas from soil into the laboratory the foundation has been supplied with a membrane. The laboratory has been equipped with two high-efficiency germanium detectors. These detectors will be used for clearance measurements on the predicted amount of 15,000 - 18,000 tonnes of non-active or nearly non-active materials, which will originate from the decommissioning of all the nuclear facilities at the Risoe-site. They will be used also for clearance measurements on buildings and land. Objects and materials to be measured for clearance are placed on a rotation table that can carry up to one tonne and can rotate once a minute to simulate some averaging of inhomogeneously distributed activity. Sensitivity and background measurements reveal that measuring times of 20 - 50 minutes would normally be sufficient to detect radionuclide concentrations of only a small fraction of the nuclide-specific clearance levels with a sufficiently low uncertainty. Probability calculations of the measurement capacity of the Clearance Laboratory indicate that the mean value of the total measuring time for all materials that potentially can be cleared would be 13 years with a 95% probability of being less than 25 years. The mean value of the annual amount of materials that can be measured in the laboratory is 600 tonnes with a 95% probability of being less than 1,200 tonnes. If needed, there is room for additional measuring systems to increase the capacity of the laboratory. (au)

  10. Mucociliary clearance from the calf lung.

    C.D. Jones

    1983-01-01

    Mucociliary clearance rate constants for ten calves were obtained using Technetium 99m-sulphur colloid complex. The mean rate constant measured at the lung for all calves was 0.012 (+/- 0.009) min-1 (half-life 58 minutes). The clearance rate constants obtained from measurements made at the larynx were higher (0.02 +/- 0.007 min-1), although not significantly higher, than those determined from measurements taken at the lung. The constants can be used to predict the particle burden on the lungs...