Decreased insulin clearance in individuals with elevated 1-h post-load plasma glucose levels.

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Maria Adelaide Marini

Full Text Available Reduced insulin clearance has been shown to predict the development of type 2 diabetes. Recently, it has been suggested that plasma glucose concentrations ≥ 8.6 mmol/l (155 mg/dl at 1 h during an oral glucose tolerance test (OGTT can identify individuals at high risk for type 2 diabetes among those who have normal glucose tolerance (NGT 1 h-high. The aim of this study was to examine whether NGT 1 h-high have a decrease in insulin clearance, as compared with NGT individuals with 1-h post-load glucose <8.6 mmol/l (l (155 mg/dl, NGT 1 h-low. To this end, 438 non-diabetic White individuals were subjected to OGTT and euglycemic-hyperinsulinemic clamp to evaluate insulin clearance and insulin sensitivity. As compared with NGT 1 h-low individuals, NGT 1 h-high had significantly higher 1-h and 2-h post-load plasma glucose and 2-h insulin levels as well as higher fasting glucose and insulin levels. NGT 1 h-high exhibited also a significant decrease in both insulin sensitivity (P<0.0001 and insulin clearance (P = 0.006 after adjusting for age, gender, adiposity measures, and insulin sensitivity. The differences in insulin clearance remained significant after adjustment for fasting glucose (P = 0.02 in addition to gender, age, and BMI. In univariate analyses adjusted for gender and age, insulin clearance was inversely correlated with body weight, body mass index, waist, fat mass, 1-h and 2-h post-load glucose levels, fasting, 1-h and 2-h post-load insulin levels, and insulin-stimulated glucose disposal. In conclusion, our data show that NGT 1 h-high have a reduction in insulin clearance as compared with NGT 1 h-low individuals; this suggests that impaired insulin clearance may contribute to sustained fasting and post-meal hyperinsulinemia.

Glomerular filtration in kidney recipients measured by plasma clearance of 169Yb-DTPA

International Nuclear Information System (INIS)

Stribrna, J.; Oppelt, A.; Jirickova, E.; Janata, V.; Kocandrle, V.; Sup, I.; Woller, P.; Franke, W.G.

1986-01-01

Values of 169 Yb-DTPA clearance (C DTPA ) calculated after a single injection were compared in 26 recipients of kidneys with renal clearance of inulin (C in ), polyfructosan S (C pf ) and creatinine (C cr ). In 21 patients the examinations were made simultaneously, in 5 patients C DTPA was measured within a short interval after the examination of renal clearance. The mean C DTPA values did not significantly differ from C cr but were significantly higher (p in and C pf (by 33% on average). Investigation of changes in C DTPA as compared with C in and C pf showed no significant difference in glomerular filtration (GF). This was measured using inulin and polyfructosan. The results showed that the differing molecular weight of inulin and polyfructosan S had no detectable effect on the GF of kidney recipients. The plasma clearance of 169 Yb-DTPA similarly to C cr overestimates the GF measured by inulin and polyfructosan clearance. (author)

Enzyme-inducing anticonvulsants increase plasma clearance of dexmedetomidine: a pharmacokinetic and pharmacodynamic study.

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Flexman, Alana M; Wong, Harvey; Riggs, K Wayne; Shih, Tina; Garcia, Paul A; Vacas, Susana; Talke, Pekka O

2014-05-01

Dexmedetomidine is useful during mapping of epileptic foci as it facilitates electrocorticography unlike most other anesthetic agents. Patients with seizure disorders taking enzyme-inducing anticonvulsants appear to be resistant to its sedative effects. The objective of the study was to compare the pharmacokinetic and pharmacodynamic profile of dexmedetomidine in healthy volunteers with volunteers with seizure disorders receiving enzyme-inducing anticonvulsant medications. Dexmedetomidine was administered using a step-wise, computer-controlled infusion to healthy volunteers (n = 8) and volunteers with seizure disorders (n = 8) taking phenytoin or carbamazapine. Sedation and dexmedetomidine plasma levels were assessed at baseline, during the infusion steps, and after discontinuation of the infusion. Sedation was assessed by using the Observer's Assessment of Alertness/Sedation Scale, Ramsay Sedation Scale, and Visual Analog Scale and processed electroencephalography (entropy) monitoring. Pharmacokinetic analysis was performed on both groups, and differences between groups were determined using the standard two-stage approach. A two-compartment model was fit to dexmedetomidine concentration-time data. Dexmedetomidine plasma clearance was 43% higher in the seizure group compared with the control group (42.7 vs. 29.9 l/h; P = 0.007). In contrast, distributional clearance and the volume of distribution of the central and peripheral compartments were similar between the groups. No difference in sedation was detected between the two groups during a controlled range of target plasma concentrations. This study demonstrates that subjects with seizure disorders taking enzyme-inducing anticonvulsant medications have an increased plasma clearance of dexmedetomidine as compared with healthy control subjects.

Isotope determinations of renal clearance equivalent with physiological clearance measurements

International Nuclear Information System (INIS)

Junges, R.

1983-01-01

The concept of renal clearance in nuclear medicine describes the tubular secretion and glomerular filtration of a substance being removed from the blood plasma. The concept of clearance as used physiologically is rather wider and includes consideration of the outflow of the substances remained back in the kidneys. The present paper discusses clearance measurements as seen from a thermodynamic point of view, in which isotope clearances become equivalent with the physiological concept of clearance. In addition, it is possible to quantify each single step of the excretory function of each kidney separately. (orig.) [de

Estimation of chromium-51 ethylene diamine tetra-acetic acid plasma clearance: A comparative assessment of simplified techniques

International Nuclear Information System (INIS)

Picciotto, G.; Cacace, G.; Mosso, R.; De Filippi, P.G.; Cesana, P.; Ropolo, R.

1992-01-01

Chromium-51 ethylene diamine tetra-acetic acid ( 51 Cr-EDTA) total plasma clearance was evaluated using a multi-sample method (i.e. 12 blood samples) as the reference compared with several simplified methods which necessitated only one or few blood samples. The following 5 methods were evaluated: Terminal slope-intercept method with 3 blood samples, simplified method of Broechner-Mortensen and 3 single-sample methods (Constable, Christensen and Groth, Tauxe). Linear regression analysis was performed. Standard error of estimate, bias and imprecision of different methods were evaluated. For 51 Cr-EDTA total plasma clearance greater than 30 ml.min -1 , the results which most approximated the reference source were obtained by the Christensen and Groth method at a sampling time of 300 min (inaccuracy of 4.9%). For clearances between 10 and 30 ml.min -1 , single-sample methods failed to give reliable results. Terminal slope-intercept and Broechner-Mortensen methods were better, with inaccuracies of 17.7% and 16.9%, respectively. Although sampling times at 180, 240 and 300 min are time-consuming for patients, 51 Cr-EDTA total plasma clearance can be accurately calculated for values greater than 10 ml.min -1 using the Broechner-Mortensen method. In patients with clearance greater than 30 ml.min -1 , single-sample techniques provide a good alternative to the multi-sample method; the choice of the method to be used depends on the degree of accuracy required. (orig.)

Improved the accuracy of 99mTc-MAG3 plasma clearance method. The problem of the calculated plasma volume and its modification

International Nuclear Information System (INIS)

Watanabe, Nami; Komatani, Akio; Yamaguchi, Koichi; Takahashi, Kazuei

1998-01-01

The 99m Tc-MAG 3 plasma clearance method (MPC method), reported by Oriuchi et al., is a simple and useful count-based gamma camera method for calculating the 99m Tc-MAG 3 plasma clearance (CL MAG ). However, a discrepancy of CL MAG calculated by MPC method (MPC-CL MAG ) from the tubular extraction rate (TER) calculated by Russell's single-sample clearance determination (Russell-TER) was noted. The calculated plasma volume is assumed to be the cause. Since the plasma volume is reported to have a linear correlation with body surface area, Dissmann's formula was applied to calculate the plasma volume. Then Dissmann's formula was replaced by Ogawa's formula in the MPC method, and the procedure was then called the modified MPC method. The CL MAG were obtained using MPC method, modified MPC method and the TER was obtained Russell's method in 95 patients with urological disorders. Then the MPC-CL MAG and modified MPC-CL MAG were compared with Russell-TER. Comparison of the MPC-CL MAG with the Russell-TER demonstrated a coefficient of correlation of 0.82, but dissociation of the slope of regression lines was found between males and females. The modified MPC-CL MAG improved the coefficient of correlation to 0.92, and diminished the dissociation of the slope of regression lines between males and females. We verified that the dissociation was due to the plasma volume calculated by Ogawa's formula. Ogawa's formula included hematocrit, body weight, body height and different coefficients for gender. The plasma volume calculated by Ogawa's formula were lower in males and higher in females than that calculated by Dissmann's formula. And marked discrepancy in the plasma volume in patients with a body surface area below 0.5 m 2 was observed. So the MPC method might become more accurate by substituting Dissmann's formula for Ogawa's formula resoluting in a method that is applicable to both males and females, children and adults in clinical use. (author)

The effect of insulin deficiency on the plasma clearance and exchange of high-density-lipoprotein phosphatidylcholine in rats.

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Martins, I J; Redgrave, T G

1992-01-01

Triolein/cholesteryl oleate/cholesterol/phosphatidylcholine emulsions designed to model the lipid composition of chylomicrons were injected intravenously into control and streptozotocin-treated insulin-deficient rats. As previously described for lymph chylomicrons, the emulsion triolein was hydrolysed and phosphatidylcholine was transferred to the plasma high-density lipoproteins (HDL). This mechanism was used to introduce a phospholipid label into HDL in vivo. The subsequent clearance of phospholipid radioactivity from the plasma of insulin-deficient rats was significantly slower than in controls (P less than 0.025). Plasma clearance was similarly slower in insulin-deficient rats after injection of HDL that was previously labelled with radioactive phospholipids. After injection, the phospholipid label redistributed rapidly between the large-particle fraction of plasma lipoproteins (very-low- and low-density lipoproteins), and the lighter and heavier fractions of HDL. Compared with control rats, in insulin-deficient rats less of the phospholipid label was distributed to the lighter HDL fraction and more to the heavier HDL fraction, and this difference was not due to changes in activity of lecithin: cholesterol acyltransferase or in the apparent activity of phospholipid transfer protein. In insulin-deficient rats the changes in HDL phospholipid clearance and exchange appeared to be secondary to the associated hypertriglyceridaemia and the related changes in distribution of phospholipids between classes of plasma lipoproteins. PMID:1536661

Evaluation of serum iohexol clearance for use in predicting carboplatin clearance in cats.

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Bailey, Dennis B; Rassnick, Kenneth M; Prey, Joshua D; Dykes, Nathan L

2009-09-01

To determine whether a glomerular filtration rate (GFR) assay based on serum iohexol clearance can be used to predict carboplatin clearance in cats. 10 cats with tumors. GFR was measured concurrently by use of plasma clearance of technetium Tc 99m-labeled diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) to yield GFR(99mTc-DTPA) and serum clearance of iohexol to yield GFR(Iohexol). A single dose of carboplatin was administered IV as a bolus. Dose was calculated by use of a target value for the area under the plasma platinum concentration-versus-time curve (AUC(Target)) and estimation of platinum clearance (CL(PT)) derived from GFR(99mTc-DTPA) as follows: dose = AUC(Target) x 2.6 x GFR(99mTc-DTPA) x body weight, where AUC(Target) is 2.75 min.mg.mL(-1). Plasma platinum concentrations were measured via atomic absorption spectrophotometry. Values for GFR(99mTc-DTPA) and GFR(Iohexol) were compared by use of least-squares regression and Bland-Altman analysis. Least-squares regression was used to determine whether CL(PT) could be predicted from GFR(99mTc-DTPA) or GFR(Iohexol) (or both). GFR(99mTc-DTPA) and GFR(Iohexol) were strongly correlated (r = 0.90), but GFR(Iohexol) values were significantly larger by a factor of approximately 1.4. Platinum clearance had a significant linear relationship to GFR(99mTc-DTPA) (CL(PT) = 2.5 x GFR(99mTc-DTPA)) and to GFR(Iohexol) (CL(PT) = [1.3 x GFR(Iohexol)] + 1.4). In cats, serum iohexol clearance was an accurate predictor of CL(PT) and can be used to calculate the carboplatin dose as follows: dose = AUC(Target) x ([1.3 x GFR(Iohexol)] + 1.4) x body weight.

Single-sample 99mTc-diethylenetriamine penta-acetate plasma clearance in advanced renal failure by the mean sojourn time approach.

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Gref, Margareta C; Karp, Kjell H

2009-03-01

The single-sample Tc-diethylenetriamine penta-acetate (DTPA) clearance method by Christensen and Groth is recommended by the Radionuclides in Nephrourology Committee on Renal Clearance for use in adults with an estimated glomerular filtration rate (GFR) > or = 30 ml/min. The purpose of this study was to test a new Tc-DTPA single-sample low clearance formula for GFR lesser than 30 ml/min. Twenty-one adult patients (29 investigations) were included. Reference clearance was calculated with both Cr-EDTA and Tc-DTPA according to Brøchner-Mortensen with samples drawn between 3 and 24 h. Single-sample clearance was calculated from a 24 h sample using the low clearance formula(Equation is included in full-text article.) C(t) is the activity of the tracer in the plasma sample t minutes after the injection and Q0 is the injected amount. ECV is the extracellular volume in ml defined as the distribution volume of the tracer. ECV is estimated from the body surface area as ECV=8116.6xbody surface area-28.2. The mean difference between reference and Tc-DTPA single-sample clearance was -0.5 ml/min (SD 1.0 ml/min) for Tc-DTPA and -0.8 ml/min (SD 1.2 ml/min) for Cr-EDTA as reference clearance. In adult patients it is possible, even with GFR lesser than 30 ml/min, to get an accurate determination of Tc-DTPA plasma clearance from a single sample using the mean sojourn time approach. The blood sample should be obtained about 24 h after injection of the GFR tracer.

Iohexol plasma clearance measurement in older adults with chronic kidney disease-sampling time matters.

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Ebert, Natalie; Loesment, Amina; Martus, Peter; Jakob, Olga; Gaedeke, Jens; Kuhlmann, Martin; Bartel, Jan; Schuchardt, Mirjam; Tölle, Markus; Huang, Tao; van der Giet, Markus; Schaeffner, Elke

2015-08-01

Accurate and precise measurement of GFR is important for patients with chronic kidney disease (CKD). Sampling time of exogenous filtration markers may have great impact on measured GFR (mGFR) results, but there is still uncertainty about optimal timing of plasma clearance measurement in patients with advanced CKD, for whom 24-h measurement is recommended. This satellite project of the Berlin Initiative Study evaluates whether 24-h iohexol plasma clearance reveals a clinically relevant difference compared with 5-h measurement in older adults. In 104 participants with a mean age of 79 years and diagnosed CKD, we performed standard GFR measurement over 5 h (mGFR300) using iohexol plasma concentrations at 120, 180, 240 and 300 min after injection. With an additional sample at 1440 min, we assessed 24-h GFR measurement (mGFR1440). Study design was cross-sectional. Calculation of mGFR was conducted with a one compartment model using the Brochner-Mortensen equation to calculate the fast component. mGFR values were compared with estimated GFR values (MDRD, CKD-EPI, BIS1, Revised Lund-Malmö and Cockcroft-Gault). In all 104 subjects, mGFR1440 was lower than mGFR300 (23 ± 8 versus 29 ± 9 mL/min/1.73 m(2), mean ± SD; P clearance up to 5 h leads to a clinically relevant overestimation of GFR compared with 24-h measurement. In clinical care, this effect should be bore in mind especially for patients with considerably reduced GFR levels. A new correction formula has been developed to predict mGFR1440 from mGFR300. For accurate GFR estimates in elderly CKD patients, we recommend the Revised Lund Malmö equation. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Diminished creatinine clearance in anorexia nervosa: reversal with weight gain.

OpenAIRE

Boag, F; Weerakoon, J; Ginsburg, J; Havard, C W; Dandona, P

1985-01-01

To assess whether patients with anorexia nervosa have abnormalities in creatinine clearance, we measured plasma creatinine concentration, urinary creatinine excretion, and creatinine clearance in 10 patients with anorexia nervosa before and during treatment. Urinary creatinine excretion and creatinine clearance were diminished in all patients. Nine patients had significant decreases in their plasma creatinine and creatinine clearance was increased even when corrected for body weight and body ...

Prediction of clearance, volume of distribution and half-life by allometric scaling and by use of plasma concentrations predicted from pharmacokinetic constants: a comparative study.

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Mahmood, I

1999-08-01

Pharmacokinetic parameters (clearance, CL, volume of distribution in the central compartment, VdC, and elimination half-life, t1/2beta) predicted by an empirical allometric approach have been compared with parameters predicted from plasma concentrations calculated by use of the pharmacokinetic constants A, B, alpha and beta, where A and B are the intercepts on the Y axis of the plot of plasma concentration against time and alpha and beta are the rate constants, both pairs of constants being for the distribution and elimination phases, respectively. The pharmacokinetic parameters of cefpiramide, actisomide, troglitazone, procaterol, moxalactam and ciprofloxacin were scaled from animal data obtained from the literature. Three methods were used to generate plots for the prediction of clearance in man: dependence of clearance on body weight (simple allometric equation); dependence of the product of clearance and maximum life-span potential (MLP) on body weight; and dependence of the product of clearance and brain weight on body weight. Plasma concentrations of the drugs were predicted in man by use of A, B, alpha and beta obtained from animal data. The predicted plasma concentrations were then used to calculate CL, VdC and t1/2beta. The pharmacokinetic parameters predicted by use of both approaches were compared with measured values. The results indicate that simple allometry did not predict clearance satisfactorily for actisomide, troglitazone, procaterol and ciprofloxacin. Use of MLP or the product of clearance and brain weight improved the prediction of clearance for these four drugs. Except for troglitazone, VdC and t1/2beta predicted for man by use of the allometric approach were comparable with measured values for the drugs studied. CL, VdC and t1/2beta predicted by use of pharmacokinetic constants were comparable with values predicted by simple allometry. Thus, if simple allometry failed to predict clearance of a drug, so did the pharmacokinetic constant

Metabolic clearance rate and urinary clearance of purified beta-core

International Nuclear Information System (INIS)

Wehmann, R.E.; Blithe, D.L.; Flack, M.R.; Nisula, B.C.

1989-01-01

We injected a highly purified preparation of the beta-core molecule, a fragment of hCG beta excreted in pregnancy urine, into five men and three women to determine its kinetic parameters, MCR, and urinary clearance. The beta-core molecule was distributed in an initial volume [1950 +/- 156 (mean +/- SEM) mL/m2 body surface area] approximately equal to the estimated plasma volume. Its disappearance was multiexponential on a semilogarithmic plot, with a rapid phase t1/2 of 3.5 +/- 0.7 min and a slow phase t1/2 of 22.4 +/- 4.2 min. The transit time (the mean time spent by a molecule of beta-core in transit) was 20.6 +/- 2.1 min. The MCR was 192.0 +/- 8.0 mL/min.m2 body surface area. About 5% of the injected dose of beta-core was excreted into the urine in the first 30 min after injection, and low levels of excretion persisted for up to 7 days. The urinary clearance rate of beta-core was 13.7 +/- 1.4 mL/min.m2, accounting for about 8% of the elimination of beta-core from the plasma. The beta-core immunoreactivity in serum and urine was characterized by gel filtration and three independent RIA systems to show that its properties were indistinguishable from those of the injected beta-core. Serum levels of beta-core in pregnant women were less than 0.2 ng/mL, while the amounts excreted in their urine were as much as 5 mg/day. Based on these clearance parameters of beta-core in normal subjects, less than 0.2% of the beta-core excreted in pregnancy urine is derived by urinary clearance of plasma beta-core. Therefore, more than 99% of the beta-core excreted in pregnancy urine is derived from beta-core in a compartment separate from plasma. In particular, these data indicate that there is relatively little placental secretion of beta-core into plasma and that placental secretion does not account for the vast majority of beta-core in pregnancy urine

Allometric scaling for predicting human clearance of bisphenol A

International Nuclear Information System (INIS)

Collet, Séverine H.; Picard-Hagen, Nicole; Lacroix, Marlène Z.; Puel, Sylvie; Viguié, Catherine; Bousquet-Melou, Alain; Toutain, Pierre-Louis; Gayrard, Véronique

2015-01-01

The investigation of interspecies differences in bisphenol A (BPA) pharmacokinetics (PK) may be useful for translating findings from animal studies to humans, identifying major processes involved in BPA clearance mechanisms, and predicting BPA PK parameters in man. For the first time, a large range of species in terms of body weight, from 0.02 kg (mice) to 495 kg (horses) was used to predict BPA clearance in man by an allometric approach. BPA PK was evaluated after intravenous administration of BPA in horses, sheep, pigs, dogs, rats and mice. A non-compartmental analysis was used to estimate plasma clearance and steady state volume of distribution and predict BPA PK parameters in humans from allometric scaling. In all the species investigated, BPA plasma clearance was high and of the same order of magnitude as their respective hepatic blood flow. By an allometric scaling, the human clearance was estimated to be 1.79 L/min (equivalent to 25.6 mL/kg.min) with a 95% prediction interval of 0.36 to 8.83 L/min. Our results support the hypothesis that there are highly efficient and hepatic mechanisms of BPA clearance in man. - Highlights: • Allometric scaling was used to predict BPA pharmacokinetic parameters in humans. • In all species, BPA plasma clearance approached hepatic blood flow. • Human BPA clearance was estimated to be 1.79 L/min

Allometric scaling for predicting human clearance of bisphenol A

Energy Technology Data Exchange (ETDEWEB)

Collet, Séverine H., E-mail: s.collet@envt.fr; Picard-Hagen, Nicole, E-mail: n.hagen-picard@envt.fr; Lacroix, Marlène Z., E-mail: m.lacroix@envt.fr; Puel, Sylvie, E-mail: s.puel@envt.fr; Viguié, Catherine, E-mail: c.viguie@envt.fr; Bousquet-Melou, Alain, E-mail: a.bousquet-Melou@envt.fr; Toutain, Pierre-Louis, E-mail: pltoutain@wanadoo.fr; Gayrard, Véronique, E-mail: v.gayrard@envt.fr

2015-05-01

The investigation of interspecies differences in bisphenol A (BPA) pharmacokinetics (PK) may be useful for translating findings from animal studies to humans, identifying major processes involved in BPA clearance mechanisms, and predicting BPA PK parameters in man. For the first time, a large range of species in terms of body weight, from 0.02 kg (mice) to 495 kg (horses) was used to predict BPA clearance in man by an allometric approach. BPA PK was evaluated after intravenous administration of BPA in horses, sheep, pigs, dogs, rats and mice. A non-compartmental analysis was used to estimate plasma clearance and steady state volume of distribution and predict BPA PK parameters in humans from allometric scaling. In all the species investigated, BPA plasma clearance was high and of the same order of magnitude as their respective hepatic blood flow. By an allometric scaling, the human clearance was estimated to be 1.79 L/min (equivalent to 25.6 mL/kg.min) with a 95% prediction interval of 0.36 to 8.83 L/min. Our results support the hypothesis that there are highly efficient and hepatic mechanisms of BPA clearance in man. - Highlights: • Allometric scaling was used to predict BPA pharmacokinetic parameters in humans. • In all species, BPA plasma clearance approached hepatic blood flow. • Human BPA clearance was estimated to be 1.79 L/min.

Single injection 51Cr EDTA plasma clearance determination in children using capillary blood samples

International Nuclear Information System (INIS)

Broechner-Mortensen, J.; Christoffersen, J.

1977-01-01

The reliability of a determination of the total 51 Cr EDTA plasma clearance (e) (and with it the glomerular filtration rate), by a simplified single injection method (injected dose: 4.5 μCi per kg b.w.) using capillary blood samples (0.2 ml), was investigated in twenty children. Clearance values determined from capillary blood samples did not differ significantly from those measured simultaneously from venous blood samples, the mean ratio+-SD being 1.02+-0.06(n = 10). The reproducibility (total day-to-day variation) of E determined from capillary blood samples was 6.7% in children with decreased renal function (n = 3) and 6.9% in children with normal renal function (n = 7). The present data indicate that the use of capillary blood samples is an accurate and very precise approach for determination of E in children. (Auth.)

Determination of renal clearance of 131I-hippuran

International Nuclear Information System (INIS)

Ridzon, S.

1982-01-01

The author presents his own method for the determination of total renal clearance of 131 I-hippuran under conditions of its diminishing plasma concentration following single intravenous administration. Total renal clearance is determined as the ratio of the amount of activity excreted into the urine over a certain time interval and of the area limited by the curve of activity decrease in plasma and by the time axis in the corresponding interval. The results are demonstrated in five investigated healthy subjects, and very good agreement of the calculated values of total renal clearance for different time intervals in the same subject is pointed out. When isotope nephrography is simultaneously performed, the method allows to determine also the values of isolated renal clearance for each kidney separately. (author)

Whole body and regional clearances of noradrenaline and adrenaline in man

DEFF Research Database (Denmark)

Christensen, N J; Galbo, H; Gjerris, A

1984-01-01

the clearance values based on arterial and venous sampling averaged 1.4 and 2.5 l/min, respectively (p less than 0.02). The difference in clearance values was due to peripheral uptake of NA averaging 45%. The plasma appearance rate on NA averaged 2.4 nmol/min before surgery and it increased to 9.5 nmol...... we found no correlation between clearance values based on venous and arterial sampling. In other experiments we measured the influence of physical exercise in young healthy subjects on the clearance rate of plasma adrenaline (A). The clearance of A, which at rest averaged 1.9 l/min tended to increase...

Assessment of glomerular filtration rate in diabetic nephropathy using the plasma clearance of 51Cr-EDTA

DEFF Research Database (Denmark)

Hansen, H P; Rossing, P; Mathiesen, E R

1998-01-01

Plasma clearance of 51Cr-EDTA is widely used to assess the glomerular filtration rate (GFR) in diabetic nephropathy. Originally, the ratio between the intravenously injected amount of tracer and the total area under the plasma concentration curve was used for the calculation of total 51Cr...... and rate of decline in GFR based upon these three methods. Bland & Altman plots were used to illustrate the range of agreement. We investigated 76 insulin-dependent diabetic (IDDM) patients with microalbuminuria or diabetic nephropathy. GFR was measured after a single intravenous injection of 3.7 MBq 51Cr...

Bile acid sequestration reduces plasma glucose levels in db/db mice by increasing its metabolic clearance rate.

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Maxi Meissner

Full Text Available AIMS/HYPOTHESIS: Bile acid sequestrants (BAS reduce plasma glucose levels in type II diabetics and in murine models of diabetes but the mechanism herein is unknown. We hypothesized that sequestrant-induced changes in hepatic glucose metabolism would underlie reduced plasma glucose levels. Therefore, in vivo glucose metabolism was assessed in db/db mice on and off BAS using tracer methodology. METHODS: Lean and diabetic db/db mice were treated with 2% (wt/wt in diet Colesevelam HCl (BAS for 2 weeks. Parameters of in vivo glucose metabolism were assessed by infusing [U-(13C]-glucose, [2-(13C]-glycerol, [1-(2H]-galactose and paracetamol for 6 hours, followed by mass isotopologue distribution analysis, and related to metabolic parameters as well as gene expression patterns. RESULTS: Compared to lean mice, db/db mice displayed an almost 3-fold lower metabolic clearance rate of glucose (p = 0.0001, a ∼300% increased glucokinase flux (p = 0.001 and a ∼200% increased total hepatic glucose production rate (p = 0.0002. BAS treatment increased glucose metabolic clearance rate by ∼37% but had no effects on glucokinase flux nor total hepatic or endogenous glucose production. Strikingly, BAS-treated db/db mice displayed reduced long-chain acylcarnitine content in skeletal muscle (p = 0.0317 but not in liver (p = 0.189. Unexpectedly, BAS treatment increased hepatic FGF21 mRNA expression 2-fold in lean mice (p = 0.030 and 3-fold in db/db mice (p = 0.002. CONCLUSIONS/INTERPRETATION: BAS induced plasma glucose lowering in db/db mice by increasing metabolic clearance rate of glucose in peripheral tissues, which coincided with decreased skeletal muscle long-chain acylcarnitine content.

Intra-operative colloid administration increases the clearance of a post-operative fluid load

DEFF Research Database (Denmark)

Borup, Tine; Hahn, Robert; Holte, K

2009-01-01

using volume kinetics based on the plasma dilution alone. The pre-operative plasma clearance was compared with the post-operative plasma clearance and patients served as their own control. RESULTS: The urinary excretion averaged 350 ml for the pre-operative infusion and 612 ml post-operatively, which...

Use of a Microsoft Excel based add-in program to calculate plasma sinistrin clearance by a two-compartment model analysis in dogs.

Science.gov (United States)

Steinbach, Sarah M L; Sturgess, Christopher P; Dunning, Mark D; Neiger, Reto

2015-06-01

Assessment of renal function by means of plasma clearance of a suitable marker has become standard procedure for estimation of glomerular filtration rate (GFR). Sinistrin, a polyfructan solely cleared by the kidney, is often used for this purpose. Pharmacokinetic modeling using adequate software is necessary to calculate disappearance rate and half-life of sinistrin. The purpose of this study was to describe the use of a Microsoft excel based add-in program to calculate plasma sinistrin clearance, as well as additional pharmacokinetic parameters such as transfer rates (k), half-life (t1/2) and volume of distribution (Vss) for sinistrin in dogs with varying degrees of renal function. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

DEFF Research Database (Denmark)

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

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 ... 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...

The efficiency of microbial protein production from tropical forages and its measurement using spot samples of urine and CrEDTA clearance from the plasma

International Nuclear Information System (INIS)

King, A.; Poppi, D.P.; McLennan, S.R.

1999-01-01

The efficiency of microbial crude protein production (MCP) expressed as g MCP/kg digestible organic matter (DOM) was much lower (P 0.75 /d). The fractional disappearance rate of CrEDTA from the plasma was similar for cattle consuming either hay (1.26-1.54%/min). The glomerular filtration rate (GFR) estimated from urinary creatinine excretion was significantly different (289 L/d vs 793 L/d, P vs R respectively). The ratio of predicted allantoin clearance determined by reference to plasma volume and FDR of CrEDTA to the actual urinary excretion was 6.7 and 9.6 for R and P respectively. This difference meant that clearance of CrEDTA could not be used as a technique in association with plasma concentration of allantoin to estimate urinary excretion of allantoin. (author)

Whole body and regional clearances of noradrenaline and adrenaline in man

DEFF Research Database (Denmark)

Christensen, N J; Galbo, H; Gjerris, Anne Cathrine Roslev

1984-01-01

we found no correlation between clearance values based on venous and arterial sampling. In other experiments we measured the influence of physical exercise in young healthy subjects on the clearance rate of plasma adrenaline (A). The clearance of A, which at rest averaged 1.9 l/min tended to increase...

Improved tumor imaging with radiolabeled monoclonal antibodies by plasma clearance with anti-antibody column

International Nuclear Information System (INIS)

Lear, J.L.; Kasliwal, R.; Feyerabend, A.; Bunn, P.; Dienhart, D.G.; Johnson, T.K.; Glenn, S.D.; Maddock, S.W.

1990-01-01

This paper reports on imaging of tumors with use of radiolabeled monoclonal antibodies (MoAs) that often hindered by high levels of background activity. The ability to lower blood pool MoA activity at a selected time after injection offers a potential method to reduce background while preserving tumor uptake. Toward this goal, the authors investigated the process of clearing MoA from patients' plasma with use of an anti-antibody column. One patient with breast cancer and four with lung cancer were given intravenous injection of 5 mCi of indium-111 KC4 (Coulter Immunology) and imaged at 20, 24, 48, and 72 hours with use of a whole-body canner coupled to a computer. Plasma clearance was performed between the 20- and 24-hour images with use of a COBEIA system. Images were inspected visually and analyzed by region-of-interest quantification

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

International Nuclear Information System (INIS)

Zuo Li; Ma Ying-Chun; Wang Mei; Zhang Chun-Li; Wang Rong-Fu; Wang Hai-Yan

2005-01-01

The objective of this study was to develop an equation to predict dual plasma sample method (DPSM) 99m Tc-diethylene triamine pentaacetic acid ( 99m Tc-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 99m Tc-DTPA plasma clearance by SPSM (sGFR). The equation recommended by the Nephrourology Committee of the Society of Nuclear Medicine was used to calculate 99m Tc-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 m 2 , ranging from 1-180 ml/min/1.73 m 2 . sGFR was significantly correlated with tGFR (r=0.9194, p 2 ; in contrast, then tGFR was±30 ml/min/1.73 m 2 , 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 m 2 )=7 4244+0.7318 x sGFR+0.0022 x sGFR 2 (n=299, r 2 =0.9428, p 2 , the diagnostic sensitivity of a cut off value of aGFR=45 ml/min/1.73 m 2 was 91.8%, and recommended as a criterion in the selection of DPSM and SPSM. When GFR ≥30 ml/min/1.73 m 2 , t

The effect of insulin deficiency on the plasma clearance and exchange of high-density-lipoprotein phosphatidylcholine in rats.

OpenAIRE

Martins, I J; Redgrave, T G

1992-01-01

Triolein/cholesteryl oleate/cholesterol/phosphatidylcholine emulsions designed to model the lipid composition of chylomicrons were injected intravenously into control and streptozotocin-treated insulin-deficient rats. As previously described for lymph chylomicrons, the emulsion triolein was hydrolysed and phosphatidylcholine was transferred to the plasma high-density lipoproteins (HDL). This mechanism was used to introduce a phospholipid label into HDL in vivo. The subsequent clearance of pho...

The influence of body posture on lithium clearance

DEFF Research Database (Denmark)

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

1988-01-01

To establish appropriate standard circumstances for lithium clearance measurements, a study was undertaken in 12 healthy volunteers. In each subject, the glomerular filtration rate (GFR), as estimated by [51Cr]EDTA plasma clearance, and the renal clearances of lithium, sodium and potassium were...... 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....... 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...

The influence of body posture on lithium clearance

DEFF Research Database (Denmark)

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

1988-01-01

To establish appropriate standard circumstances for lithium clearance measurements, a study was undertaken in 12 healthy volunteers. In each subject, the glomerular filtration rate (GFR), as estimated by [51Cr]EDTA plasma clearance, and the renal clearances of lithium, sodium and potassium were...... 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...... 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....

Application of measuring 99mTc-MAG3 plasma clearance based on one-compartment model (MPC method) to pediatric patients

International Nuclear Information System (INIS)

Koizumi, Kiyoshi; Higashida, Kousuke; Arbab, A.S.; Toyama, Keiji; Arai, Takao; Yoshitomi, Tatsuya.

1997-01-01

Measurement of 99m Tc-MAG3 plasma clearance based on 1-compartment model (MPC method) were applied to 12 pediatric patients and evaluated for the factors which might affect the calculated results. Depth correction is a critical factor for the measurement of renal uptake. Three different equations for estimating renal depth were compared with the real depth measured by ultrasonography. The equation proposed by K. Itoh was suitable though the equations by T. Ito and Raynaud were insufficient. Estimation of distribution volume, which is regarded as circulating plasma volume (CPV), is also critical for the calculation of MAG3 clearance by MPC method. Precisely, hematocrit measured by venous sampling and circulating blood volume (CBV) calculated as 7.5% of body weight are used for estimation of CPV. However, assumed CPV as 5% of body weight was acceptable if the hematocrit was not severely deviated from the normal value. Simplified MPC method utilizing two factors mentioned above gave a positive correlation with Russell's one point sampling method. In conclusion, MPC method is applicable for pediatric patients. (author)

[Plasma clearance of ethanol and its excretion in the milk of rural women who consume pulque].

Science.gov (United States)

Argote-Espinosa, R M; Flores-Huerta, S; Hernández-Montes, H; Villalpando-Hernández, S

1992-01-01

Women from rural areas of the central plateau of Mexico drink during pregnancy and lactation a mild alcoholic beverage called pulque as a galactogogue. Ethanol present in milk could have a harmful effect on growth and development of breast-fed children. The purpose of this study was to quantify the ethanol consumed as pulque by eleven lactating rural women as well as its clearance rate in blood and milk. Mothers were separated in two groups depending upon the ethanol ingested in a single dose of pulque 0.21 +/- 0.08 g/kg of body weight (group A) and 0.44 +/- 0.11 g/kg (group B). Maximal concentration of ethanol was reached in milk at 60 minutes and almost equaled that in plasma. Both groups showed a similar clearance pattern regardless of the volume of pulque ingested. Clearance rates between groups were different: ethanol concentration in milk at 60 min were 8.4 +/- 3.0 mg/dL for group A and 26.2 +/- 7.0 mg/dL for group B. Two hours later ethanol levels were 3.6 +/- 3.4 mg/dL and 23.3 +/- 9.4 mg/dL respectively. Clearance rates were slower in mothers showing the highest concentration of ethanol in milk. The present data demonstrate that there is no differential elimination of ethanol in maternal blood and milk following ingestion of a moderate amount of pulque during lactation. The amount of ethanol received by infants through milk is relatively low and therefore it is unlikely to have harmful effects on them. Pulque consumption adds about 350 kcal/day to the customary dietary intake of these lactating women.

Uncertainty analysis of 99mTc-HEPIDA liver clearance determination

International Nuclear Information System (INIS)

Surma, M. J.

2005-01-01

The aim of the study was to obtain information on the accuracy and precision of 99mT c-HEPIDA hepatic (Cl H p) and plasma (Cl P l) clearances and selection of an appropriate estimator of the measurement uncertainty of a single determination of these quantities. In a simulation (Monte Carlo) experiment, it was assumed that the recorded results of plasma and hepatic clearances, as obtained from 185 patients, provided authentic information about 99mT c-HEPIDA behaviour in the body over a wide range of the clearances studied. The time-course 99mT c-HEPIDA concentration in blood plasma has been described by means of biexponential function with parameter values derived for each patient. For each patient, using these data and urinary excretion data, there had been 5000 simulations performed; in each of the latter, the directly measured numbers have been substituted by simulated ones, obtained by means of varying the real ones, using random generated values. These reflected errors of plasma and radioactive standard pipetting (from 1 to 5%) and stochasticity of counting radioactive decay (1%). The time of blood sampling and urine voiding was also varied, assuming realistic uncertainty. The varied values were then used for computation of the simulated clearances. From the 5000 calculated clearances for each patient, mean-values were calculated, as well as mean standard errors, standard deviations and mean uncertainty of measurements using a widely accepted rule of partial error propagation, and, in addition, a modified rule of the latter. Accuracy of clearance (Cl P l, Cl H p, Cl U r) determination was assessed on the basis of comparison of mean values from simulations with those from directly recorded values. Precision was identified with standard deviation of each of the 5000 simulations. The uncertainty thus obtained was compared with results of calculated traditional and modified uncertainty. There was good agreement between standard deviation of the simulations with

A comparison of analytic procedures for measurement of fractional dextran clearances

NARCIS (Netherlands)

Hemmelder, MH; de Jong, PE; de Zeeuw, D

Fractional dextran clearances have been extensively used to study glomerular size selectivity. We report on an analysis of different laboratory procedures involved in measuring fractional dextran clearances. The deproteinization of plasma samples by 20% trichloroacetic acid (TCA) revealed a protein

Transfer of plasma lipoprotein components and of plasma proteins into aortas of cholesterol-fed rabbits. Molecular size as a determinant of plasma lipoprotein influx

International Nuclear Information System (INIS)

Stender, S.; Zilversmit, D.B.

1981-01-01

The arterial influx of esterified and free cholesterol from low density lipoproteins and very low density lipoproteins in 20 hypercholesterolemic rabbits was measured simultaneously by the use of lipoproteins labeled in vivo with [ 3 H]- and [ 14 C]-cholesterol. The simultaneous arterial influx of either [ 3 H]-leucine-labeled very low density lipoproteins, low density lipoproteins, high density lipoproteins, or plasma proteins was also measured in each rabbit. The arterial influx was calculated as intimal clearance, i.e., the influx of a given fraction divided by its plasma concentration. The intimal clearance of low density lipoprotein esterified cholesterol was equal to that for the apolipoproteins of that fraction, which is compatible with an arterial influx of intact low density lipoprotein molecules. The intimal clearance of very low density apolipoprotein or cholesteryl ester was less than that for low density lipoprotein, whereas high density lipoprotein and albumin clearances exceeded low density lipoprotein clearance by 1.5- to 3-fold. The intimal clearances of plasma proteins, high density, low density, and very low density lipoproteins decreased linearly with the logarithm of the macromolecular diameter. This indicates that the arterial influx of three plasma lipoprotein fractions and of plasma proteins proceeds by similar mechanisms. Apparently the relative intimal clearances of lipoproteins are more dependent on their size relative to pores or vesicular diameters at the plasma-artery interface than on specific interactions between lipoproteins and the arterial intimal surface

The metabolic clearance rate of corticosterone in lean and obese male Zucker rats

International Nuclear Information System (INIS)

White, B.D.; Corll, C.B.; Porter, J.R.

1989-01-01

The obese Zucker rat is an animal model of human juvenile-onset obesity. These rats exhibit numerous endocrine and metabolic abnormalities. Adrenalectomy of obese rats has been shown to reduce or reverse several of these abnormalities, thereby implying that corticosterone may contribute to the expression of obesity in this animal. Furthermore, it has been shown that the circadian rhythm of plasma corticosterone is disturbed in obese Zucker rats resulting in elevated morning plasma corticosterone concentrations in obese rats as compared to lean rats. In a effort to better elucidate the mechanism of the elevated morning levels of plasma corticosterone, the metabolic clearance rate of corticosterone was determined in the morning for lean and obese male Zucker rats (12 to 20 weeks). Additionally, the biliary and urinary excretion of labeled corticosterone and/or its metabolites were determined. The metabolic clearance rate of corticosterone was significantly greater in obese rats than in their lean counterparts. Both the metabolic clearance rate and the volume of compartments significantly correlated with body weight. No correlation was found between body weight and the elimination rate constant. The increased metabolic clearance rate of obese rats appeared to be due to an increase in the physiologic distribution of corticosterone and not to an alteration in the enzymes responsible for corticosterone metabolism. It appears that the metabolic clearance rate of corticosterone in obese Zucker rats does not contribute to elevated morning concentrations of plasma corticosterone previously observed in these animals. It suggests that the adrenal corticosterone secretion rate must actually be greater than one would expect from the plasma corticosterone concentrations alone

[Proceeding: Production rate, metabolic clearance rate and mean plasma concentration of cortisol in hyperthyroidism (author's transl)].

Science.gov (United States)

Linquette, M; Lefebvre, J; Racadot, A; Cappoen, J P

1975-01-01

The adrenocortical function was studied in 23 patients with hyperthyroidism and compared with a group of 15 normal subjects. Parameters of adrenal function were determined with 1,2(3)H-cortisol. The half-life of cortisol is significantly shortened in hyperthyroidism, as compared to normal subjects (49,5 +/- 6,6 min vs 68,3 +/- 10,5 min) and metabolic clearance rate is increased (418,5 +/- 89,5 L/24 h vs 237,5 +/- 48,5 L/24 h, for normal subjects). The production rate of cortisol, calculated from specific and cumulate activities of THE and THF is increased in hyperthyroidism expressed as mg/24 h or mg/m2/24 h (respectively : 26,7 +/- 7,8 mg/24 h vs 15,7 +/- 3 mg/24 h and 16,9 +/- 4,6 mg/m2/24 h vs 9,5 +/- 1,8 mg/m2/24 h). The mean plasma concentration, calculated as the radio (see article) is not statiscally different in hyperthyroid and normal subjects (6,8 +/- 2,1 microg/100 ml vs 7,3 +/- 1,9 microg/100 ml). 7 patients were reinvestigated after treatment of thyrotoxicosis when they were clinically and biologically in euthyroid state. All the values were normalized, without statistically significant difference from control (T 1/2 = 65,4 +/- 18 min, Metb Cl. Rate : 255 +/- 64,5 L/24 h, production rate : 15,6 +/- 1,8 mg/24 h and 9 +/- 1,4 mg/m2/24 h. mean plasma concentration : 6,8 +/- 2,8 microg/100 ml). Shortened cortisol half life, increased metabolic clearance rate and production rate, and normal mean plasma concentration have been reported in hyperthyroidism (Peterson, Copinschi, Gallagher). These changes, secondary to thyroid hormone excess, are the consequences of increased hepatic catabolism of cortisol. The activity of 11 OH steroid deshydrogenase is increased, as demonstrated by increased ratio (see article) in normal subjects (0,001 less than p less than 0,005). There is a high proportion of 17 kéto metabolites (E, DHE, THE) whose feed-back effect is weak as compared to 17 OH metabolites (F, DHF, THF). The hypothalamo-hypophyso-adrenal system is

Online feedback-controlled renal constant infusion clearances in rats.

Science.gov (United States)

Schock-Kusch, Daniel; Shulhevich, Yury; Xie, Qing; Hesser, Juergen; Stsepankou, Dzmitry; Neudecker, Sabine; Friedemann, Jochen; Koenig, Stefan; Heinrich, Ralf; Hoecklin, Friederike; Pill, Johannes; Gretz, Norbert

2012-08-01

Constant infusion clearance techniques using exogenous renal markers are considered the gold standard for assessing the glomerular filtration rate. Here we describe a constant infusion clearance method in rats allowing the real-time monitoring of steady-state conditions using an automated closed-loop approach based on the transcutaneous measurement of the renal marker FITC-sinistrin. In order to optimize parameters to reach steady-state conditions as fast as possible, a Matlab-based simulation tool was established. Based on this, a real-time feedback-regulated approach for constant infusion clearance monitoring was developed. This was validated by determining hourly FITC-sinistrin plasma concentrations and the glomerular filtration rate in healthy and unilaterally nephrectomized rats. The transcutaneously assessed FITC-sinistrin fluorescence signal was found to reflect the plasma concentration. Our method allows the precise determination of the onset of steady-state marker concentration. Moreover, the steady state can be monitored and controlled in real time for several hours. This procedure is simple to perform since no urine samples and only one blood sample are required. Thus, we developed a real-time feedback-based system for optimal regulation and monitoring of a constant infusion clearance technique.

Lipoprotein lipase activity and chylomicron clearance in rats fed a high fat diet

International Nuclear Information System (INIS)

Brown, C.M.; Layman, D.K.

1988-01-01

The relationships of tissue and plasma lipoprotein lipase (LPL) activities to tissue uptake and plasma clearance of 14 C-labeled chylomicron-triglyceride ( 14 C-CM-TG) were studied in female rats fed isoenergetic and isonitrogenous control (12% kJ from fat) or high fat diets (72% kJ from fat) for 8 wk. Animals fed the high-fat diet had higher levels of fasting plasma triglycerides and lower LPL activities in heart, renal adipose tissue and post-heparin plasma. Changes in LPL activities of skeletal muscles varied among muscles with higher values in the soleus and plantaris (32-61%) and no differences in the gastrocnemius. The lower LPL activity in renal adipose tissue was associated with lower uptake of fatty acids from 14 C-CM-TG by adipose. Fatty-acid uptake from labeled TG was not associated with tissue LPL activity in other tissues. Clearance of 14 C-CM-TG from plasma and the half-lives of 14 C-CM-TG were similar in both dietary groups. These data indicate that tissue and plasma LPL activities are not a direct index of uptake of fatty acids by tissues or clearance of chylomicron triglycerides

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

International Nuclear Information System (INIS)

Brueggemann, G.

1980-01-01

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 131 I-hippuran, and the parameters for describing the isotope rephrogram (ING) with 131 I-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) [de

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

DEFF Research Database (Denmark)

Henriksen, Ulrik L; Henriksen, Jens H

2014-01-01

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...

Plasma clearance of sup(99m)Tc-N/2,4-dimethyl-acetanilido/iminodiacetate complex as a measure of parenchymal liver damage

International Nuclear Information System (INIS)

Studniarek, M.; Durski, K.; Liniecki, J.; Akademia Medyczna, Lodz

1983-01-01

Fifty-two patients were studied with various diseases affecting liver parenchyma. Any disorders of bile transport were excluded on the basis of dynamic liver scintigraphy using intravenously injected N/2,4-dimethyl acetanilid/iminodiacetate sup(99m)Tc complex (HEPIDA). The activity concentration of sup(99m)Tc-HEPIDA in plasma was measured from 5 through 60 min post injection. Clearance of the substance (Clsub(B)) was calculated from blood plasma disappearance curves and compared with results of 13 laboratory tests used conventionally for assessment of damage of the liver and its functional capacity; age and body weight was also included in the analysis. Statistical relations were studied using linear regression analysis of two variables, multiple regression analysis as well as multidimensional analysis of variance. It was demonstrated that sup(99m)Tc-HEPIDA clearance is a simple, accurate and repeatable measure of liver parenchyma damage. In males, values of Clsub(B) above 245 ml min - 1 /1.73 m 2 exclude hepatic damage with high probability; values below 195 ml min - 1 /1.73 m 2 indicate evident impairment of liver parenchyma function. (orig.) [de

Lithium clearance method and the renal response to low-dose dopamine in man

DEFF Research Database (Denmark)

Olsen, N V; Olsen, M H; Fogh-Andersen, N

1993-01-01

.00 hours on three different occasions. After an overnight fast, the subjects were water-loaded and clearance studies were started at 09.00 hours with a 1h baseline period and three 1h periods during dopamine infusion. 2. Baseline sodium clearance with placebo was 0.65 +/- 0.35 ml/min, but with lithium......-induced changes in effective renal plasma flow, glomerular filtration rate or osmolal clearance. Neither lithium nor dopamine influenced plasma concentrations of renin, aldosterone or atrial natriuretic peptide. 4. In conclusion, single test doses of lithium, as normally used in lithium clearance studies......1. The effect of a single dose of lithium on renal function before and during intravenous infusion of dopamine (3 micrograms min-1 kg-1) was investigated in 12 healthy males. In a double-blind and randomized design, 450mg or 600mg of lithium carbonate or placebo was administered orally at 22...

Lithium clearance method and the renal response to low-dose dopamine in man

DEFF Research Database (Denmark)

Olsen, Niels Vidiendal; Olsen, M H; Fogh-Andersen, N

1993-01-01

.00 hours on three different occasions. After an overnight fast, the subjects were water-loaded and clearance studies were started at 09.00 hours with a 1h baseline period and three 1h periods during dopamine infusion. 2. Baseline sodium clearance with placebo was 0.65 +/- 0.35 ml/min, but with lithium...... in effective renal plasma flow, glomerular filtration rate or osmolal clearance. Neither lithium nor dopamine influenced plasma concentrations of renin, aldosterone or atrial natriuretic peptide. 4. In conclusion, single test doses of lithium, as normally used in lithium clearance studies, increase baseline......1. The effect of a single dose of lithium on renal function before and during intravenous infusion of dopamine (3 micrograms min-1 kg-1) was investigated in 12 healthy males. In a double-blind and randomized design, 450mg or 600mg of lithium carbonate or placebo was administered orally at 22...

Dextran fractional clearance studies in acute dengue infection.

Directory of Open Access Journals (Sweden)

Julie Nguyen-Pouplin

2011-08-01

Full Text Available Although increased capillary permeability is the major clinical feature associated with severe dengue infections the mechanisms underlying this phenomenon remain unclear. Dextran clearance methodology has been used to investigate the molecular sieving properties of the microvasculature in clinical situations associated with altered permeability, including during pregnancy and in various renal disorders. In order to better understand the characteristics of the vascular leak associated with dengue we undertook formal dextran clearance studies in Vietnamese dengue patients and healthy volunteers.We carried out serial clearance studies in 15 young adult males with acute dengue and evidence of vascular leakage a during the phase of maximal leakage and b one and three months later, as well as in 16 healthy control subjects. Interestingly we found no difference in the clearance profiles of neutral dextran solutions among the dengue patients at any time-point or in comparison to the healthy volunteers.The surface glycocalyx layer, a fibre-matrix of proteoglycans, glycosaminoglycans, and plasma proteins, forms a complex with the underlying endothelial cells to regulate plasma volume within circumscribed limits. It is likely that during dengue infections loss of plasma proteins from this layer alters the permeability characteristics of the complex; physical and/or electrostatic interactions between the dextran molecules and the glycocalyx structure may temporarily restore normal function, rendering the technique unsuitable for assessing permeability in these patients. The implications for resuscitation of patients with dengue shock syndrome (DSS are potentially important. It is possible that continuous low-dose infusions of dextran may help to stabilize the permeability barrier in patients with profound or refractory shock, reducing the need for repeated boluses, limiting the total colloid volume required. Formal clinical studies should help to assess

Contrast media and glomerular filtration: dose dependence of clearance for three agents

International Nuclear Information System (INIS)

Baeck, S.E.K.; Krutzen, E.; Nilsson-Ehle, P.

1988-01-01

Determination of plasma clearance of contrast agents has been advocated as a means to assess glomerular filtration rate. To evaluate the feasibility of different agents for this purpose, we have compared, in healthy volunteers, the dose dependence of plasma clearance for three contrast media (iohexol, a nonionic agent, and iothalamate and metrizoate, which are ionic substances), with special emphasis on the lower dose range (2-20 mL corresponding to 0.9-12.9 g, depending on dose and agent). Iohexol and iothalamate were cleared at constant rates, irrespective of given dose, whereas metrizoate clearance increased significantly at lower doses. In general, the clearances or iothalamate and metrizoate were, respectively, moderately and markedly higher than that of iohexol. The clearance of different doses of metrizoate (2 mL versus a radiographic dose of 40 mL or more) was also compared with the clearance of [ 51 Cr]EDTA in two groups of patients with reduced renal function. When compared with [ 51 Cr]EDTA in patients with renal dysfunction, metrizoate was cleared significantly faster after a 2-mL dose, whereas clearances were identical when the metrizoate dose was 40 mL or more. These findings indicate that tubular secretion plays an active role in the elimination of metrizoate. The pharmacokinetic properties of iohexol, in combination with its low toxicity, make it a suitable agent for determination of glomerular filtration rate in clinical practice

Optimization of protein and peptide drugs based on the mechanisms of kidney clearance.

Science.gov (United States)

Huang, Jiaguo; Wu, Huizi

2018-05-30

Development of proteins and peptides into drugs has been considered as a promising strategy to target certain diseases. However, only few proteins and peptides has been approved as new drugs into the market each year. One major problem is that proteins and peptides often exhibit short plasma half-life times, which limits the application for their clinical use. In most cases a short half-life time is not effective to deliver sufficient amount of drugs to the target organs and tissues, which is generally caused by fast renal clearance and low plasma stability due to proteolytic degradation during systemic circulation, because the most common clearance pathway of small proteins and peptides is through glomerular filtration by the kidneys. In this review, enzymatic degradation of proteins and peptides were discussed. Furthermore, several approaches to lengthen the half-life of peptides and proteins drugs based on the unique structures of glomerular capillary wall and the mechanisms of glomerular filtration were summarized, such as increasing the size and hydrodynamic diameter; increasing the negative charge to delay the filtration; increasing plasma protein binding to decrease plasma clearance. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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

International Nuclear Information System (INIS)

Hagemann, J.; Li Min Su; Strangfeld, D.; Schuerer, M.; Siewert, H.; Pietsch, R.; Kruse, I.; Priem, F.

1988-01-01

Order of magnitude and standard deviation of 99m Tc-DTPA and 131 I-hippurate slope clearance were analyzed successively in 56 male Wistar rats. The clearance of 99m Tc-DTPA was 17.4 ± 3.43 μl · s -1 (100 g b-w) -1 , of 131 I-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 99m Tc-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 99m Tc-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 99m Tc-DTPA clearance in Wistar rats seems to be well suited. (author)

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

International Nuclear Information System (INIS)

Hagemann, J.; Li Min Su; Strangfeld, D.; Schuerer, M.; Siewert, H.; Pietsch, R.; Kruse, I.; Priem, F.

1988-01-01

Averages and standard deviations of 99m Tc-DTPA and 131 I-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 99m Tc-DTPA was 17.4 ± 3.4, that of 131 I-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. 99m Tc-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 99m Tc-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 99m Tc-DTPA seems well applicable in Wistar rats. (author)

Quantitative assessment of caffeine partial clearances in man.

Science.gov (United States)

Lelo, A; Miners, J O; Robson, R A; Birkett, D J

1986-01-01

Five subjects who participated in an earlier study (Lelo et al., 1986b) of the comparative pharmacokinetics of caffeine (CA) and its primary monodemethylated metabolites paraxanthine (PX), theobromine (TB) and theophylline (TP) were administered CA to steady-state. Using areas under the plasma concentration-time curves for each of the dimethylxanthines derived from CA in the steady-state study and individual plasma clearances of PX, TB and TP determined in the previous study, the fractional conversion of CA to PX, TB and TP and the individual partial clearances of CA have been defined. The mean (+/- s.d.) fractional conversion of CA to PX, TB and TP was 79.6 +/- 21.0%, 10.8 +/- 2.4% and 3.7 +/- 1.3%, respectively. When only demethylation pathways are considered PX, TB and TP accounted for 83.9 +/- 5.4%, 12.1 +/- 4.1% and 4.0 +/- 1.4%, respectively of the CA demethylations. The mean partial clearance of CA to PX was approximately 8-fold and 23-fold greater than those to TB and TP respectively. These data confirm earlier reports that PX is the major metabolite of CA in humans but suggest that PX formation is quantitatively more important than previously believed. PMID:3756066

CVVHD treatment with CARPEDIEM: small solute clearance at different blood and dialysate flows with three different surface area filter configurations.

Science.gov (United States)

Lorenzin, Anna; Garzotto, Francesco; Alghisi, Alberta; Neri, Mauro; Galeano, Dario; Aresu, Stefania; Pani, Antonello; Vidal, Enrico; Ricci, Zaccaroa; Murer, Luisa; Goldstein, Stuart L; Ronco, Claudio

2016-10-01

The CARdiorenal PEDIatric EMergency (CARPEDIEM) machine was originally designed to perform only continuous venovenous hemofiltration (CVVH) in neonatal and pediatric patients. In some cases, adequate convective clearance may not be reached because of a limited blood flow. In such conditions, the application of diffusive clearance [continuous venovenous hemodialysis (CVVHD)] would help optimize blood purification. In this study, the CARPEDIEM™ machine was modified to enable the circulation of dialysis through the filter allowing testing of the performance of CARPEDIEM™ machine in CVVHD. Three different polyethersulfone hemodialyzers (surface area = 0.1 m(2), 0.2 m(2), and 0.35 m(2), respectively) were tested in vitro with a scheduled combination of plasma flow rates (Qp = 10-20-30 ml/min) and dialysis fluid flow rate (Qd = 5-10-15 ml/min). Three sessions were performed in co-current and one in counter-current configuration (as control) for each filter size. Clearance was measured from the blood and dialysate sides and results with mass balance error greater than 5 % were discarded. Urea and creatinine clearances for each plasma/dialysate combination are reported: clearance increase progressively for every filter proportionally to plasma flow rates. Similarly, clearances increase progressively with dialysate flow rates at a given plasma flow. The clearance curve tends to present a steep increase for small increases in plasma flow in the range below 10 ml/min, while the curve tends to plateau for values averaging 30 ml/min. As expected, the plateau is reached earlier with the smaller filter showing the effect of membrane surface-area limitation. At every plasma flow, the effect of dialysate flow increase is evident and well defined, showing that saturation of effluent was not achieved completely in any of the experimental conditions explored. No differences (p > 0.05 for all values) were obtained in experiments using whole blood instead of

Depressed reticuloendothelial clearance of platelets in rats after trauma.

Science.gov (United States)

Kaplan, J E; Moon, D G; Minnear, F L; Saba, T M

1984-02-01

Platelet microembolization may contribute to microcirculatory and organ damage following trauma and shock. It is hypothesized that posttraumatic reticuloendothelial depression predisposes to such microembolization by failure to clear altered platelets from the circulation. The present study evaluated the short-term (1 h) clearance and organ localization of radiolabeled homologous damaged platelets in normal rats and in rats following sublethal Noble-Collip drum trauma. Platelets were collected in citrated platelet-rich plasma from normal rats and labeled with 51Cr in citrated saline. Platelets were altered by repeated centrifugation in protein-free medium. These platelets differed functionally and morphologically from normal platelets. Disappearance of iv injected damaged platelets conformed to a two-compartment exponential clearance. Velocity of clearance in the rapid compartment correlated with hepatic platelet localization, whereas velocity of clearance in the second compartment correlated with splenic platelet localization. Clearance rate of the rapid compartment was depressed at 1 h after trauma and elevated at 24 h. These changes were associated with a decrease in hepatic platelet localization at 1 h and an increase above normal at 24 h. Splenic platelet localization was decreased by 3 h following trauma. Pulmonary platelet localization was increased at all times following trauma. It is concluded that the posttrauma state is associated with a defect in the reticuloendothelial system clearance of altered platelets, which may augment embolization of platelets in the lung.

Hepatic and muscle clearance of physostigmine in the rat after i.v. administration

International Nuclear Information System (INIS)

Somani, S.M.; Unni, L.K.

1986-01-01

This study presents a method to calculate the extraction ratio (ER) from in vivo time course of liver metabolism using the physiological and pharmacokinetic parameters such as plasma flow rate, partition coefficient of drug between tissue and plasma and the elimination rate constant from tissues. Rats were administered 3 H-physostigmine (Phy), 100 μg/kg i.v.; and were sacrificed at various times. Tissues were removed and Phy and its metabolites were determined by HPLC. Half-life of Phy in liver and muscle was 24 and 20 min, respectively. ER of Phy in liver was .71 which showed a slight decrease at 10 min. Muscle ER was found to be .347 up to 5 min. Hepatic clearance was calculated to be 23.08 ml/min/kg (34.9% of systemic clearance) and the intrinsic clearance was 83.73 ml/min/kg which indicates that the changes in blood flow to the liver can cause a variation in the systematic clearance. Percentage dose of Phy retained in muscle was maximum and the clearance was 5.2 ml/min/kg suggesting that muscle might be acting as a storage depot for Phy prolonging the pharmacological effects. About 30-40% of radioactivity in the liver could not be washed off by 10% TCA or organic solvents indicating the irreversible binding of drug or metabolite to liver macromolecule

Effect of hyperthyroidism on clearance and secretion of glucagon in man.

Science.gov (United States)

Dimitriadis, G; Hatziagelaki, E; Mitrou, P; Lambadiari, V; Maratou, E; Raptis, A E; Gerich, J E; Raptis, S A

2011-04-01

Glucagon has been proposed to contribute to the increased glucose production found in hyperthyroidism. However, fasting plasma glucagon levels are not increased in hyperthyroidism suggesting that the activity of the α-cell is normal. Nevertheless, an increase in the clearance rate of glucagon may mask increased glucagon secretion. This study was designed to examine the effects of hyperthyroidism on the kinetics of glucagon. A primed-continuous infusion of glucagon was administered to 9 euthyroid and 9 hyperthyroid subjects at 3 sequential rates (1,200, 3,000 and 6,000 pg/kg/min, each given for 2 h). Arterialized blood was drawn at 15-30 min intervals for determination of glucagon. Fasting plasma glucagon levels were comparable in euthyroids (195±8 pg/ml) and hyperthyroids (231±16 pg/ml). During infusions (1,200, 3,000 and 6,000 pg/kg/min), plasma glucagon increased to 387±19, 624±44 and 977±51 pg/ml in euthyroids and to 348±23, 597±42 and 938±56 pg/ml in hyperthyroids respectively. At these infusion rates, metabolic clearance of glucagon (ml/kg/min) was 6.6±0.5, 7.4±0.6 and 7.9±0.5 in euthyroids and 12.6±2, 8.9±1 and 8.8±0.6 in hyperthyroids, respectively. Metabolic clearance of glucagon differed between hyperthyroids and euthyroids at 1 200 pg/kg/min infusion rate (p=0.001). The basal delivery rate of glucagon (ng/kg/min) was 1.3±0.1 in euthyroids and 2.9±0.6 in hyperthyroids (p=0.0005). In hyperthyroidism, the secretion and metabolic clearance rates of glucagon are increased. These effects may explain the changes in plasma glucagon levels observed in hyperthyroidism and support the important role of glucagon in increasing endogenous glucose production in this condition. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

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

International Nuclear Information System (INIS)

Xie Peng; Huang Jianmin; Pan Liping; Liu Xiaomei; Wei Lingge; Gao Jianqing

2010-01-01

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 99 Tc m -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)

Detection of Viral RNA in Tissues following Plasma Clearance from an Ebola Virus Infected Patient.

Directory of Open Access Journals (Sweden)

Mirella Biava

2017-01-01

Full Text Available An unprecedented Ebola virus (EBOV epidemic occurred in 2013-2016 in West Africa. Over this time the epidemic exponentially grew and moved to Europe and North America, with several imported cases and many Health Care Workers (HCW infected. Better understanding of EBOV infection patterns in different body compartments is mandatory to develop new countermeasures, as well as to fully comprehend the pathways of human-to-human transmission. We have longitudinally explored the persistence of EBOV-specific negative sense genomic RNA (neg-RNA and the presence of positive sense RNA (pos-RNA, including both replication intermediate (antigenomic-RNA and messenger RNA (mRNA molecules, in the upper and lower respiratory tract, as compared to plasma, in a HCW infected with EBOV in Sierra Leone, who was hospitalized in the high isolation facility of the National Institute for Infectious Diseases "Lazzaro Spallanzani" (INMI, Rome, Italy. We observed persistence of pos-RNA and neg-RNAs in longitudinally collected specimens of the lower respiratory tract, even after viral clearance from plasma, suggesting possible local replication. The purpose of the present study is to enhance the knowledge on the biological features of EBOV that can contribute to the human-to-human transmissibility and to develop effective intervention strategies. However, further investigation is needed in order to better understand the clinical meaning of viral replication and shedding in the respiratory tract.

Metformin lowers plasma triglycerides by promoting VLDL-triglyceride clearance by brown adipose tissue in mice.

Science.gov (United States)

Geerling, Janine J; Boon, Mariëtte R; van der Zon, Gerard C; van den Berg, Sjoerd A A; van den Hoek, Anita M; Lombès, Marc; Princen, Hans M G; Havekes, Louis M; Rensen, Patrick C N; Guigas, Bruno

2014-03-01

Metformin is the first-line drug for the treatment of type 2 diabetes. Besides its well-characterized antihyperglycemic properties, metformin also lowers plasma VLDL triglyceride (TG). In this study, we investigated the underlying mechanisms in APOE*3-Leiden.CETP mice, a well-established model for human-like lipoprotein metabolism. We found that metformin markedly lowered plasma total cholesterol and TG levels, an effect mostly due to a decrease in VLDL-TG, whereas HDL was slightly increased. Strikingly, metformin did not affect hepatic VLDL-TG production, VLDL particle composition, and hepatic lipid composition but selectively enhanced clearance of glycerol tri[(3)H]oleate-labeled VLDL-like emulsion particles into brown adipose tissue (BAT). BAT mass and lipid droplet content were reduced in metformin-treated mice, pointing to increased BAT activation. In addition, both AMP-activated protein kinase α1 (AMPKα1) expression and activity and HSL and mitochondrial content were increased in BAT. Furthermore, therapeutic concentrations of metformin increased AMPK and HSL activities and promoted lipolysis in T37i differentiated brown adipocytes. Collectively, our results identify BAT as an important player in the TG-lowering effect of metformin by enhancing VLDL-TG uptake, intracellular TG lipolysis, and subsequent mitochondrial fatty acid oxidation. Targeting BAT might therefore be considered as a future therapeutic strategy for the treatment of dyslipidemia.

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

Energy Technology Data Exchange (ETDEWEB)

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.)

CYP2B6*6 allele and age substantially reduce steady-state ketamine clearance in chronic pain patients: impact on adverse effects.

Science.gov (United States)

Li, Yibai; Jackson, Kate A; Slon, Barry; Hardy, Janet R; Franco, Michael; William, Leeroy; Poon, Peter; Coller, Janet K; Hutchinson, Mark R; Currow, David C; Somogyi, Andrew A

2015-08-01

Ketamine analgesia is limited by low intrinsic efficacy compounded by large interindividual variability in drug responses, possibly due to the heterogeneity in drug concentration. The CYP2B6*6 allele is associated with substantially reduced ketamine metabolism in vitro and, therefore, may affect ketamine clearance. Our aims were to examine the impact of the CYP2B6*6 allele on ketamine plasma clearance and on adverse effects in chronic pain patients. CYP2B6 genotypes were identified in 49 chronic pain patients who received 24 h continuous subcutaneous infusions of ketamine. Steady-state plasma concentrations of ketamine (Css,k ) and norketamine (Css,nk ) were determined using HPLC. The median plasma clearance of ketamine after 100 mg 24 h(-1) dose was significantly lower in patients with the CYP2B6*6/*6 (21.6 l h(-1) ) and CYP2B6*1/*6 (40.6 l h(-1) ) genotypes compared with patients with the CYP2B6*1/*1 genotype (68.1 l h(-1) , P ketamine : norketamine plasma metabolic ratio was significantly higher in patients with the CYP2B6*6/*6 genotype than in those with the CYP2B6*1/*6 and the CYP2B6*1/*1 genotypes (P ketamine plasma clearance in chronic pain patients. The decreased clearance and resultant higher plasma concentrations may be associated with a higher incidence of ketamine adverse effects. © 2015 The British Pharmacological Society.

Lung mucociliary clearance

International Nuclear Information System (INIS)

Mortensen, J.; Lange, P.; Nyboe, J.; Groth, S.

1994-01-01

The aim of this study was to establish reference values for mucociliary clearance and mucociliary clearance reserve capacity as determined by β 2 -adrenergic agonist-induced increase in mucociliary clearance. We studied 62 healthy females (n=33) and males (n=29). Their ages ranged evenly between 18 and 84 years. Fifty-three of the subjects were life-long non-smokers, while nine were ex-smokers. Multiple linear regression analyses showed that mucociliary clearance was significantly faster when the radioaerosol was deposited in the central airways than when it was deposited in the peripheral airways, and faster in life-long non-smokers than in ex-smokers. There was no influence of age, and no convincing association with sex. The variation was less within than between subjects. Mean mucociliary clearance reserve capacity was 21.3% (SD: 10.0%, P 2 agonist-induced increase in lung mucociliary clearance was significantly larger (P<0.05) than the stimulation which has previously been reported in patients with asthma, bronchiectasis or cystic fibrosis. The signal-to-noise ratio of the mucociliary clearance reserve capacity in relation to measurement of baseline mucociliary clearance indicates that measurement of mucociliary clearance reserve capacity may be a more efficient means of distinguishing between ''normal'' and ''abnormal'' mucociliary clearance than single measurement of baseline mucociliary clearance. (orig.)

A simple estimation of the renal plasma flow

International Nuclear Information System (INIS)

Shinpo, Takako

1987-01-01

The renal plasma flow was determined conventionally by the excretive ratio to urine using a 131 I-Hippuran renogram. In this report, we proposed the renal clearance, the product of the disappearance rate coefficient and the maximum counts of the bladder, for the simple quantitative value of renal plasma flow. The disappearance rate coefficient was calculated by approximating the exponential function of the initial slope from the disappearance curve of the heart. The renal clearances was compared with the renal plasma flow calculated by the conventional method. The results gave a high correlation coefficient of r = 0.91. The renal clearances can be calculated easily and it offers useful renogram information. (author)

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

DEFF Research Database (Denmark)

Rehling, M

1988-01-01

[99mTc]DTPA has achieved widespread use for the measurement of glomerular filtration rate (GFR) with the single injection plasma clearance technique and for gamma-camera renography. However, the quality of the commercial preparations varies. The purpose of the present investigation was to study...... the 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.......7% and 1.1%, respectively. The plasma clearance of [99mTc]DTPA was on an average 3.7% higher than that of [51Cr]EDTA in 27 patients. It is concluded that the [99mTc]DTPA preparation is reliable for the measurement of GFR. The preparation is stable for at least six hours at room temperature...

Comparison of the endogenous creatinine clearance, the creatinin clearance calculated without urine collection and the isotope clearance

International Nuclear Information System (INIS)

Mohacsi, Gabor; Lang, Jenoe; Csernay, Laszlo; Sonkodi, Sandor; Orvostudomanyi Egyetem, Szeged

1987-01-01

Observations are reported relating to the endogenous creatinine clearance, the Tc-99m-EDTA-complex clearance and the creatinine clearance estimated via a selected mathematical formula, with special regard to the problems of renal insufficiency and the nephrotic syndrome. The activity applied was in the range of 3.7-7.4 MBq. It was observed that measurement of the isotope clearance can also be applied to determine the endogeneous creatinine clearance in otherwise less suitable patients. A reliable result is obtained even if the renal function is restricted, but the accuracy of the method may be reduced in nephrotic syndrome cases. (author) 24 refs

Creatinine clearance test

Science.gov (United States)

Serum creatinine clearance; Kidney function - creatinine clearance; Renal function - creatinine clearance ... Creatinine is a chemical waste product of creatine. Creatine is a chemical the body makes to supply ...

Estimation of Hepatic Function Using 99mTc-DISIDA Plasma Clearance Rate

International Nuclear Information System (INIS)

Lee, M. S.; Yoo, H. S.; Lee, J. T.; Park, C. Y.

1983-01-01

Various methods to determine hepatic function have been studied, and among these, calculated maximal removal rate of ICG (ICG R-max) is more accurate and sensitive index for quantification of hepatic function. But calculation of ICG R-max is time-consuming, invasive, and expensive study, and even ICG R-max 1 day study is still complicated. So we tried to evaluated of hepatic function test using 99mTc-DISIDA plasma clearance rate. The author studied 11 cases of normal control, 4 cases of acute hepatitis, 8 cases of chronic hepatitis, and 19 cases of liver cirrhosis. The results were as follows: 1. In normal control, DISIDA-K was 0.70 min -1 , in liver cirrhosis 0.25 min -1 , in acute hepatitis 0.46 min -1 , and in chronic hepatitis 0.14min -1 . The most severe depressed DISIDA-K value was observed in liver cirrhosis. 2. Comparison of DISIDA-K value to liver function indices revealed no correlation between DISIDA-K value and serum albumin, prothrombin time, total bilirubin, SGOT, and alkaline phosphatase. 3. DISIDA-K value in liver cirrhosis with complication such as ascites, splenomegaly, esophageal varices, and hepatic coma was more decreased than without complication. With the above result, calculation of DISIDA-K value was found easily available, accurate, and simple index for quantification of hepatic function.

Estimation of 131J-Jodohippurateclearance by a simplified method using a single plasma sample

International Nuclear Information System (INIS)

Botsch, H.; Golde, G.; Kampf, D.

1980-01-01

Theoretical volumes calculated from the reciprocal of the plasma concentration of 131 J-Jodohippurate were compared in 95 patients with clearance values calculated by the 2-compartment-method and in 18 patients with conventional PAH-clearance. For estimating Hippurate-clearance from a single blood sampling the most favorable time is 45 min. after injection (r = 0.96; clearance 400/ml/min.: r = 0.98). Clearance values may be derived from the formula: C = 0.4 + 7.26 V - 0.021 x V 2 (V = injected activity/activity per l plasma taken 45 min. after injection). The simplicity, precision and reproducibility of the above mentioned clearance-method is emphasized. (orig.) [de

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

DEFF Research Database (Denmark)

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

2015-01-01

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 mean 4.5 m...

Iodine-clearance-equivalent (123I) for delineation of thyroid dysfunctions

International Nuclear Information System (INIS)

Licht, E.

1981-01-01

In 138 patients whose thyroid function was proved by R T 3 -uptake, T 4 -RIA, T 3 -RIA, FT 4 , FT 3 the iodine uptake of the thyroid 2 and 4 hours after application of 200 μCi 123 iodine p.o. or i.v., respectively after application of 34 μCi 131 iodine p.o. was determined. 2 hours after application of radioiodine plasma acitivity was measured. The ratio between increase/hour of uptake and plasma level of activity after 2 hours was taken as clearance equivalent, which does not measure the correct value of iodine clearance but is sufficiently related to it. The type of radioiodine and the method of application had no influence on the results. There was significant difference between euthyroid adenoma, euthyroid adenoma and hyperthyroid adenoma. The advantage of the technique is the practicability, the short occupancy of the uptake system and the reduction of radiation dosage by consequent use of 123 iodine. The second uptake measurement coincides with thyroid imaging, which results in time saving for the patient. (orig.) [de

Serum creatinine and creatinine clearance for predicting plasma methotrexate concentrations after high-dose methotrexate chemotherapy for the treatment for childhood lymphoblastic malignancies.

Science.gov (United States)

Xu, Wei-qun; Zhang, Ling-yan; Chen, Xue-ying; Pan, Bin-hua; Mao, Jun-qing; Song, Hua; Li, Jing-yuang; Tang, Yong-min

2014-01-01

Monitoring of plasma methotrexate (MTX) concentrations allows for therapeutic adjustments in treating childhood acute lymphoblastic leukemia (ALL) or non-Hodgkin lymphoma (NHL) with high-dose MTX (HDMTX). We tested the hypothesis that assessment of creatinine clearance (CrCl) and/or serum Cr may be a suitable means of monitoring plasma MTX concentrations. All children in the study had ALL or NHL, were in complete remission, and received HDMTX (3 or 5 g/m(2))+leucovorin. Plasma MTX concentrations were measured at 24, 48, and 96 h. CrCl was determined at 24 and 48 h. Correlations between 24- and 48-h plasma MTX concentrations and CrCl and serum Cr concentrations were determined. CrCl and serum Cr concentrations were compared over time between children who had delayed and non-delayed MTX elimination. A total of 105 children were included. There were significant negative correlations between CrCl at 24 and 48 h and plasma MTX concentrations at 24 (both p < 0.001) and 48 h (both p < 0.001). There were significant positive correlations between serum Cr concentrations at both 24 and 48 h and plasma MTX concentrations at 24 (both p < 0.001) and 48 h (both p < 0.001). There were 88 (30.2 %) instances of elimination delay. Children with elimination delay had significantly lower CrCl and higher Cr concentrations at 24 and 48 h compared with children without elimination delay (all p < 0.05). Our findings suggest that, with further refinement, assessment of renal function may be a useful means of monitoring plasma MTX concentrations during HDMTX for ALL and NHL.

Mucociliary clearance

DEFF Research Database (Denmark)

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...... 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...

Gastric clearance of alpha-1-antitrypsin under cimetidine perfusion. New test to detect protein-losing gastropathy

International Nuclear Information System (INIS)

Florent, C.; Vidon, N.; Flourie, B.; Carmantrand, A.; Zerbani, A.; Maurel, M.; Bernier, J.J.

1986-01-01

Gastric losses of plasma are usually measured with radiolabeled macromolecules. This method is expensive and cumbersome. Direct measurement of exudated plasma proteins are ineffective since proteins are denaturated by acidic gastric juice and pepsin. It was recently shown that albumin measurement after immediate neutralization allowed detection of gastric protein losses, but this method is quite complex and time consuming. We studied alpha 1-antitrypsin and 51Cr-labeled protein clearance in gastric juice during normal saline and cimetidine (1.5 mg/kg/hr) infusion in six healthy volunteers and six patients with exudative gastropathy. alpha 1-Antitrypsin was measurable in all samples during cimetidine infusion: alpha 1-AT and 51Cr losses were significantly correlated (P less than 0.001). The upper limit of gastric alpha 1-AT clearance in controls was 0.86 ml/hr (mean + 2 SD). Using this value, there was no overlapping between patients and controls. The upper limit of 51Cr test was 1.87 ml/hr (mean + 2 SD) in controls but gastric clearance of 51Cr was below this value in one patient. This suggests that the measurement of alpha 1-AT gastric clearance during cimetidine perfusion is a good test to detect an exudative gastropathy. This test is inexpensive and lasts only 3 hr

Determination of separate kidney clearance by means of the Tc-DTPA complex and the scintillation camera

International Nuclear Information System (INIS)

Piepsz, A.; Dobbeleir, A.; Erbsmann, F.

1975-01-01

A new quantitative method to determine the separate kidney is described. This method is based on the use of the Tc-DTPA complex administered in a single intraveinous injection, a scintillation camera and continuous computerized data recording for 20 minutes at 20 sec. intervals. By definition the slope of the kidney radioactivity curve, divided by the corresponding plasma concentration, represents at each instant the glomerular clearance of the kidney. This only applies before the 3rd minute following the intraveinous tracer injection, when the filtered radioactivity has not yet left the kidney area. Between the 60th and 180th sec., 6 clearance values may be determined for each kidney. For each 20-sec. time interval the renal activity increase per minute is divided by the plasma concentration during the same interval and the average of these values is taken as the glomerular clearance figure. Some results have been analysed. The test could end 3 min. after the intraveinous injection. Continuation of the recording for 20 min. gives a complete dynamic picture of the kidney function [fr

Impairment of aminopyrine clearance in aspirin-damaged canine gastric mucosa

International Nuclear Information System (INIS)

Miller, T.A.; Henagan, J.M.; Loy, T.M.

1983-01-01

Using an in vivo canine chambered stomach preparation, the clearance of [ 14 C]aminopyrine across mucosa when intravenously infused and the back-diffusion of this substance from gastric lumen to mucosa when topically applied to gastric epithelium were evaluated in aspirin-damaged gastric epithelium. In mucosa damaged by either 20 mM or 40 mM aspirin, the recovery of [ 14 C]aminopyrine, when topically mixed with acid (pH . 1.1) perfusate solution, was not significantly different from nondamaged control mucosa. In addition, the degree of ''trapping'' of this substance from back-diffusion was not different in damaged mucosa from that observed in nondamaged epithelium. In contrast, when [ 14 C]aminopyrine was intravenously infused, its clearance was significantly impaired in aspirin-damaged mucosa when compared with control studies, as evidenced by the increased ''trapping'' of this substance in injured epithelium. These findings indicate that movement of aminopyrine from plasma to gastric lumen is impaired in damaged epithelium, making the aminopyrine clearance technique an unreliable method to accurately measure absolute gastric blood flow in this experimental setting

Dimerization of glycoprotein Ibα is not sufficient to induce platelet clearance.

Science.gov (United States)

Liang, X; Syed, A K; Russell, S R; Ware, J; Li, R

2016-02-01

ESSENTIALS: Many anti-glycoprotein (GP)Ibα antibodies induce platelet clearance in a dimer-dependent manner. Characterization of monoclonal antibodies that bind the mechanosensitive domain (MSD) of GPIbα. An anti-MSD antibody binds two copies of GPIbα in platelets but does not induce platelet clearance. The prevailing clustering model of GPIbα signaling is incorrect or needs revision. The mechanism of platelet clearance is not clear. Many antibodies binding the membrane-distal ligand-binding domain of glycoprotein (GP)Ibα induce rapid clearance of platelets and acute thrombocytopenia, which requires the bifurcated antibody structure. It was thought that binding of these antibodies induced lateral dimerization or clustering of GPIbα in the plasma membrane, which leads to downstream signaling and platelet clearance. However, many antibodies targeting GPIbβ and GPIX, which are associated with GPIbα in the GPIb-IX complex, do not induce platelet clearance, which is in contradiction to the clustering model. To test whether dimerization or clustering of GPIbα is sufficient to transmit the signal that leads to platelet clearance. We have recently raised several mAbs targeting the mechanosensitive domain (MSD) of GPIbα. Binding of these anti-MSD antibodies was characterized with biochemical methods. Their ability to stimulate platelets and induce platelet clearance in mice was assessed. Infusion of anti-MSD antibodies does not cause thrombocytopenia in mice. These antibodies show no detectable effects on platelet activation and aggregation in vitro. Further biochemical investigation showed that the anti-MSD antibody 3D1 binds two copies of GPIbα on the platelet surface. Therefore, lateral dimerization of GPIbα induced by antibody binding is not sufficient to initiate GPIb-IX signaling and induce platelet clearance. Our results suggest that a factor other than or in addition to clustering of GPIbα is required to induce platelet clearance. © 2015 International

No evidence for a direct effect of von Willebrand factor's ABH blood group antigens on von Willebrand factor clearance

NARCIS (Netherlands)

Groeneveld, D J; van Bekkum, T; Cheung, K L; Dirven, R J; Castaman, G; Reitsma, P H; van Vlijmen, B; Eikenboom, J

BACKGROUND: One of the major determinants of von Willebrand factor (VWF) plasma levels is ABO blood group status, and individuals with blood group O have ~ 25% lower plasma levels. The exact mechanism behind this relationship remains unknown, although effects on clearance have been postulated.

Caloric Restriction and Exercise Increase Plasma ANGPTL4 Levels in Humans via Elevated Free Fatty Acids

NARCIS (Netherlands)

Kersten, A.H.; Lichtenstein, L.L.; Steenbergen, E.; Mudde, C.M.; Hendriks, H.F.J.; Hesselink, M.K.; Schrauwen, P.; Müller, M.R.

2009-01-01

Objective - Plasma lipoprotein levels are determined by the balance between lipoprotein production and clearance. Recently, angiopoietin-like protein 4 (ANGPTL4) was uncovered as a novel endocrine factor that potently raises plasma triglyceride levels by inhibiting triglyceride clearance. However,

Caloric restriction and exercise increase plasma ANGPTL4 levels in humans via elevated free fatty acids.

NARCIS (Netherlands)

Kersten, S.; Lichtenstein, L.; Steenbergen, E.; Mudde, K.; Hendriks, H.F.; Hesselink, M.K.; Schrauwen, P.; Muller, M

2009-01-01

OBJECTIVE: Plasma lipoprotein levels are determined by the balance between lipoprotein production and clearance. Recently, angiopoietin-like protein 4 (ANGPTL4) was uncovered as a novel endocrine factor that potently raises plasma triglyceride levels by inhibiting triglyceride clearance. However,

Caloric restriction and exercise increase plasma ANGPTL4 levels in humans via elevated free fatty acids

NARCIS (Netherlands)

Kersten, S.; Lichtenstein, L.; Steenbergen, E.; Mudde, K.; Hendriks, H.F.J.; Hesselink, M.K.; Schrauwen, P.; Müller, M.

2009-01-01

OBJECTIVE-: Plasma lipoprotein levels are determined by the balance between lipoprotein production and clearance. Recently, angiopoietin-like protein 4 (ANGPTL4) was uncovered as a novel endocrine factor that potently raises plasma triglyceride levels by inhibiting triglyceride clearance. However,

Colloid clearance rate changes in children with homozygous-β-thalassemia in relation to blood transfusion

International Nuclear Information System (INIS)

Dimitriou, P.A.; Karpathios, T.E.; Antipas, S.E.; Fretzayias, A.M.; Kasfiki, A.G.; Melissinos, K.G.; Matsaniotis, N.S.

1980-01-01

The plasma clearance rate of heat denatured human serum albumin (DHAI-125, 5 mg/kg body weight) was studied in 20 children with homozygous-β-thalassemia before and 7-10 days after blood transfusion. A significant increase of the DHAI-125 clearance rate (P < 0.02) was found 7-10 days after blood transfusion while the spleen presented its minimum size. This finding may be relevant to the improved intrasplenic blood circulation after blood transfusion due to the release of the blood trapped within the spleen. (orig.)

Factor XIII as a modulator of plasma fibronectin alterations during experimental bacteremia.

Science.gov (United States)

Kiener, J L; Cho, E; Saba, T M

1986-11-01

Fibronectin is found in plasma as well as in association with connective tissue and cell surfaces. Depletion of plasma fibronectin is often observed in septic trauma and burned patients, while experimental rats often manifest hyperfibronectinemia with sepsis. Since Factor XIII may influence the rate of clearance and deposition of plasma fibronectin into tissues, we evaluated the temporal changes in plasma fibronectin and plasma Factor XIII following bacteremia and RE blockade in rats in an attempt to understand the mechanism leading to elevation of fibronectin levels in bacteremic rats, which is distinct from that observed with RE blockade. Clearance of exogenously administered fibronectin after bacteremia was also determined. Rats received either saline, Pseudomonas aeruginosa (1 X 10(9) organisms), gelatinized RE test lipid emulsion (50 mg/100 gm B.W.), or emulsion followed by Pseudomonas. Plasma fibronectin and Factor XIII were determined at 0, 2, 24, and 48 hours post-blockade or bacteremia. At 24 and 48 hr following bacteremia alone or bacteremia after RE blockade, there was a significant elevation (p less than 0.05) of plasma fibronectin and a concomitant decrease (p less than 0.05) of plasma factor XIII activity. Extractable tissue fibronectin from liver and spleen was also increased at 24 and 48 hours following R.E. blockade plus bacteremia. In addition, the plasma clearance of human fibronectin was significantly prolonged (p less than 0.05) following bacterial challenge. Infusion of activated Factor XIII (20 units/rat) during a period of hyperfibronectinemia (908.0 +/- 55.1 micrograms/ml) resulted in a significant (p less than 0.05) decrease in plasma fibronectin (548.5 +/- 49.9 micrograms/ml) within 30 min. Thus Factor XIII deficiency in rats with bacteremia may contribute to the elevation in plasma fibronectin by altering kinetics associated with the clearance of fibronectin from the blood.

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

International Nuclear Information System (INIS)

Kubota, Shintaro; Usui, Hideo; Kawagoshi, Hiroshi

2014-06-01

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)

Iohexol clearance is superior to creatinine-based renal function estimating equations in detecting short-term renal function decline in chronic heart failure.

Science.gov (United States)

Cvan Trobec, Katja; Kerec Kos, Mojca; von Haehling, Stephan; Anker, Stefan D; Macdougall, Iain C; Ponikowski, Piotr; Lainscak, Mitja

2015-12-01

To compare the performance of iohexol plasma clearance and creatinine-based renal function estimating equations in monitoring longitudinal renal function changes in chronic heart failure (CHF) patients, and to assess the effects of body composition on the equation performance. Iohexol plasma clearance was measured in 43 CHF patients at baseline and after at least 6 months. Simultaneously, renal function was estimated with five creatinine-based equations (four- and six-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Cockcroft-Gault adjusted for lean body mass, Chronic Kidney Disease Epidemiology Collaboration equation) and body composition was assessed using bioimpedance and dual-energy x-ray absorptiometry. Over a median follow-up of 7.5 months (range 6-17 months), iohexol clearance significantly declined (52.8 vs 44.4 mL/[min ×1.73 m2], P=0.001). This decline was significantly higher in patients receiving mineralocorticoid receptor antagonists at baseline (mean decline -22% of baseline value vs -3%, P=0.037). Mean serum creatinine concentration did not change significantly during follow-up and no creatinine-based renal function estimating equation was able to detect the significant longitudinal decline of renal function determined by iohexol clearance. After accounting for body composition, the accuracy of the equations improved, but not their ability to detect renal function decline. Renal function measured with iohexol plasma clearance showed relevant decline in CHF patients, particularly in those treated with mineralocorticoid receptor antagonists. None of the equations for renal function estimation was able to detect these changes. ClinicalTrials.gov registration number: NCT01829880.

Modelling hemoglobin and hemoglobin:haptoglobin complex clearance in a non-rodent species– pharmacokinetic and therapeutic implications

Directory of Open Access Journals (Sweden)

Felicitas S Boretti

2014-10-01

Full Text Available Preclinical studies suggest that haptoglobin (Hp supplementation could be an effective therapeutic modality during acute or chronic hemolytic diseases. Hp prevents Hb extravasation and neutralizes Hb’s oxidative and NO scavenging activity in the vasculature. Small animal models such as mouse, rat and guinea pig appear to be valuable to provide proof-of-concept for Hb neutralization by Hp in diverse pre-clinical conditions. However, these species differ significantly from human in the clearance of Hb:Hp complexes, which leads to long persistence of circulating Hb:Hp complexes after administration of human plasma derived Hp. Alternative animal models must therefore be explored to guide pre-clinical development of these potential therapeutics. In contrast to rodents, dogs have high Hp plasma concentrations comparable to human. In this study we show that like human macrophages, dog peripheral blood monocyte derived macrophages express a glucocorticoid inducible endocytic clearance pathways with a high specificity for the Hb:Hp complex. Evaluating the Beagle dog as a non-rodent model species we provide the first pharmacokinetic parameter estimates of free Hb and Hb:Hp phenotype complexes. The data reflect a drastically reduced volume of distribution (Vc of the complex compared to free Hb, increased exposures (Cmax and AUC and significantly reduced total body clearance (CL with a terminal half-life (t1/2 of approximately 12 hours. Distribution and clearance was identical for dog and human Hb (± glucocorticoid stimulation and for dimeric and multimeric Hp preparations bound to Hb. Collectively, our study supports the dog as a non-rodent animal model to study pharmacological and pharmacokinetic aspects of Hb clearance systems and apply the model to studying Hp therapeutics.

RENAL CLEARANCE AND URINARY EXCRETION OF CIPROFLOXACIN IN GOATS

Directory of Open Access Journals (Sweden)

Z. IQBAL, I. JAVED, B. ASLAM, F. MUHAMMAD AND I. U. JAN

2007-10-01

Full Text Available The renal clearance and urinary excretion of ciprofloxacin were investigated in eight healthy female goats. In each animal, ciprofloxacin was administered intramuscularly at the rate of 5 mg/kg body weight. Following drug administration, blood and urine samples were collected at different time intervals and analyzed for ciprofloxacin and creatinine. High performance liquid chromatography (HPLC was used to determine the drug concentration in the plasma and urine. The value of diuresis after single administration of ciprofloxacin was 0.073 ± 0.014 ml/min/kg. Mean (± SE values for renal clearance of creatinine and ciprofloxacin were 1.870 ± 0.385 and 0.982 ± 0.166 ml/min/kg, respectively. The ratio between the renal clearance of ciprofloxacin and that of creatinine remained less than one, which was indicative of back diffusion. The mean (± SE value for the cumulative percent of ciprofloxacin dose excreted at 10 hours following its intramuscular administration was 13.03 ± 2.07. Based on these results, it was evident that besides glomerular filtration, renal handling of drug involved back diffusion also. It was concluded that in local goats glomerular filtration rate (GFR was lower than that reported for their foreign counterparts.

Lansoprazole increases testosterone metabolism and clearance in male Sprague-Dawley rats: implications for leydig cell carcinogenesis

International Nuclear Information System (INIS)

Coulson, Michelle; Gibson, G. Gordon; Plant, Nick; Hammond, Tim; Graham, Mark

2003-01-01

Leydig cell tumours (LCTs) are frequently observed during rodent carcinogenicity studies, however, the significance of this effect to humans remains a matter of debate. Many chemicals that produce LCTs also induce hepatic cytochromes P450 (CYPs), but it is unknown whether these two phenomena are causally related. Our aim was to investigate the existence of a liver-testis axis wherein microsomal enzyme inducers enhance testosterone metabolic clearance, resulting in a drop in circulating hormone levels and a consequent hypertrophic response from the hypothalamic-pituitary-testis axis. Lansoprazole was selected as the model compound as it induces hepatic CYPs and produces LCTs in rats. Male Sprague-Dawley rats were dosed with lansoprazole (150 mg/kg/day) or vehicle for 14 days. Lansoprazole treatment produced effects on the liver consistent with an enhanced metabolic capacity, including significant increases in relative liver weights, total microsomal CYP content, individual CYP protein levels, and enhanced CYP-dependent testosterone metabolism in vitro. Following intravenous administration of [ 14 C]testosterone, lansoprazole-treated rats exhibited a significantly smaller area under the curve and significantly higher plasma clearance. Significant reductions in plasma and testicular testosterone levels were observed, confirming the ability of this compound to perturb androgen homeostasis. No significant changes in plasma LH, FSH, or prolactin levels were detected under our experimental conditions. Lansoprazole treatment exerted no marked effects on testicular testosterone metabolism. In summary, lansoprazole treatment induced hepatic CYP-dependent testosterone metabolism in vitro and enhanced plasma clearance of radiolabelled testosterone in vivo. These effects may contribute to depletion of circulating testosterone levels and hence play a role in the mode of LCT induction in lansoprazole-treated rats

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

International Nuclear Information System (INIS)

Hojabr, M.; Rajabi, H.; Eftekhari, M.

2004-01-01

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 in 99m Tc- MAG 3 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-MAG 3 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-MAG 3 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, R 2 =0.98, SE=15). Conventional

Metabolic clearance and production rates of human growth hormone

Science.gov (United States)

Taylor, Andrew L.; Finster, Joseph L.; Mintz, Daniel H.

1969-01-01

The metabolic clearance rate (MCR) of human growth hormone (HGH) was determined by the constant infusion to equilibrium technique utilizing HGH-125I. 22 control subjects had a MCR of 229 ±52 ml/min (mean ±SD). No difference was evident between sexes, or between various age groups. Patients with acromegaly demonstrated normal MCR's. Moreover, acute elevations of plasma growth hormone concentrations in normal subjects did not alter the MCR of HGH. The MCR was relatively constant from day to day and within the day when subjects were evaluated in the supine position. In contrast, the assumption of the upright position was associated with a mean 24% decrease in the MCR. These results were contrasted with the MCR of HGH observed in a small number of patients with altered thyroid function or diabetes mellitus. In six patients with hypothyroidism the MCR (131 ±36 ml/min) was significantly decreased (P < 0.001); whereas the MCR in eight patients with hyperthyroidism (240 ±57 ml/min) did not differ from control subjects. The MCR in eight patients with insulin-independent diabetes mellitus (IID) (185 ±41 ml/min) and in eight patients with insulin-dependent diabetes mellitus (IDD) (136 ±31 ml/min) were significantly different from control subjects (P = < 0.05 and P = < 0.001, respectively). These data were interpreted to indicate that the plasma HGH-removing mechanism(s) is not saturated at physiologic plasma HGH levels, that plasma HGH levels alone may not permit distinction between variations in pituitary release of the hormone and its rate of clearance from the plasma, and that the estimation of the MCR of HGH may help clarify the mechanism of abnormal plasma HGH responses to various stimuli. Production rates of HGH (PR) in control subjects (347 ±173 mμg/min) were contrasted with hyperthyroid patients (529 ±242 mμg/min, P < 0.05), hypothyroid patients (160 ±69 mμg/min, P < 0.02), IID (245 ±100 mμg/min, NS), and IDD (363 ±153 mμg/min, NS). Considerable

Differential proteomics analysis of the surface heterogeneity of dextran iron oxide nanoparticles and the implications for their in vivo clearance.

Science.gov (United States)

Simberg, Dmitri; Park, Ji-Ho; Karmali, Priya P; Zhang, Wan-Ming; Merkulov, Sergei; McCrae, Keith; Bhatia, Sangeeta N; Sailor, Michael; Ruoslahti, Erkki

2009-08-01

In order to understand the role of plasma proteins in the rapid liver clearance of dextran-coated superparamagnetic iron oxide (SPIO) in vivo, we analyzed the full repertoire of SPIO-binding blood proteins using novel two-dimensional differential mass spectrometry approach. The identified proteins showed specificity for surface domains of the nanoparticles: mannan-binding lectins bound to the dextran coating, histidine-rich glycoprotein and kininogen bound to the iron oxide part, and the complement lectin and contact clotting factors were secondary binders. Nanoparticle clearance studies in knockout mice suggested that these proteins, as well as several previously identified opsonins, do not play a significant role in the SPIO clearance. However, both the dextran coat and the iron oxide core remained accessible to specific probes after incubation of SPIO in plasma, suggesting that the nanoparticle surface could be available for recognition by macrophages, regardless of protein coating. These data provide guidance to rational design of bioinert, long-circulating nanoparticles.

Optimum time of blood sampling for determination of glomerular filtration rate by single-injection [51Cr]EDTA plasma clearance

International Nuclear Information System (INIS)

Broechner-Mortensen, J.; Roedbro, P.

1976-01-01

We have investigated the influence on reproducibility of total [ 51 Cr]EDTA plasma clearance (E) of various times and numbers of blood samples in patients with normal (13 patients) and low (14 patients) renal function. The study aims at fixing a clinically useful procedure suitable for all levels of renal function. Six different types of E were evaluated with time periods for blood sampling between 3 and 5 h after tracer injection, and the variation from counting radioactivity, s 1 , was determined as part of the total variation, s 2 . Optimum mean time, t(E), for blood sampling was calculated as a function of E, as the mean time giving the least change in E for a given change in the 'final slope' of the plasma curve. For patients with normal E, s 1 did not contribute significantly to s 2 , and t(E) was about 2h. For patients with low renal function s 1 contributed significantly to s 2 , and t(E) increased steeply with decreasing E. The relative error in s 1 from fixed Etypes was calculated for all levels of renal function. The results indicate that blood sampling individualized according to predicted E values is not necessary. A sufficient precision of E can be achieved for all function levels from three blood samples drawn at 180, 240, and 300 min after injection. (Auth.)

Optimal sampling strategies to assess inulin clearance in children by the inulin single-injection method

NARCIS (Netherlands)

van Rossum, Lyonne K.; Mathot, Ron A. A.; Cransberg, Karlien; Vulto, Arnold G.

2003-01-01

Glomerular filtration rate in patients can be determined by estimating the plasma clearance of inulin with the single-injection method. In this method, a single bolus injection of inulin is administered and several blood samples are collected. For practical and convenient application of this method

Diagnostic value of renal clearance techniques using iodo-hippuran /sup 131/I and /sup 99m/-DTPA

Energy Technology Data Exchange (ETDEWEB)

Heidenreich, P; Hoer, G [Technische Univ. Muenchen (Germany, F.R.). Nuklearmedizinische Klinik und Poliklinik

1976-01-01

Methods and clinical indications of divided renal clearance determination using /sup 131/I-hippuran are presented and their value as a diagnostic tool in urology is shown by two case reports. For quantitative assessment of renal function we prefer the whole body clearance (with partial shielding of kidneys and bladder) which obviates the necessity of the theoretical assumption of compartmental distribution of radiopharmaceuticals. Using simplified clearance techniques only based on analysis of plasma disappearance curves (slope clearance one- and two-compartment model), clinically useful results are also obtainable, especially in follow up studies. The evaluation of tubular and glomerular kidney function by simultaneous application of /sup 131/I-hippuran and sup(99m)Tc-DTPA is suitable for estimation of filtration fraction in patients with urological and nephrological diseases. Even with regard to therapy and follow up studies of urinary tract tuberculosis, remarkable dignostic informations may be achieved.

Determination of the technetium-99m mercaptoacetyltriglycine plasma clearance in children by means of a single blood sample: a multicentre study

International Nuclear Information System (INIS)

Piepsz, A.; Gordon, I.; Hahn, K.; Kolinska, J.; Kotzerke, J.; Sixt, R.

1993-01-01

A multicentree European study was undertaken in order to determine a reasonable algorithm allowing the determination of overall technetium-99m mercaptoacetyltriglycine clearance using a single blood sample. Employing multiple blood sample clearance as a reference method, it was shown that an acceptable estimation of the MAG3 renal clearance could be obtained using a blood sample taken at any time between 30 and 40 min after tracer injection. After correction for body surface area comparison of clearance determined using (a) the single blood sample and (b) the multiple blood samples provided a coefficient of correlation of 0.949 and an SEE of 27 ml/min. This algorithm is valid for clearance values higher than 100 ml/min/1.73 m 2 and for children older than 1 year of age. (orig.)

Surface code—biophysical signals for apoptotic cell clearance

International Nuclear Information System (INIS)

Biermann, Mona; Maueröder, Christian; Brauner, Jan M; Chaurio, Ricardo; Herrmann, Martin; Muñoz, Luis E; Janko, Christina

2013-01-01

Apoptotic cell death and the clearance of dying cells play an important and physiological role in embryonic development and normal tissue turnover. In contrast to necrosis, apoptosis proceeds in an anti-inflammatory manner. It is orchestrated by the timed release and/or exposure of so-called ‘find-me’, ‘eat me’ and ‘tolerate me’ signals. Mononuclear phagocytes are attracted by various ‘find-me’ signals, including proteins, nucleotides, and phospholipids released by the dying cell, whereas the involvement of granulocytes is prevented via ‘stay away’ signals. The exposure of anionic phospholipids like phosphatidylserine (PS) by apoptotic cells on the outer leaflet of the plasma membrane is one of the main ‘eat me’ signals. PS is recognized by a number of innate receptors as well as by soluble bridging molecules on the surface of phagocytes. Importantly, phagocytes are able to discriminate between viable and apoptotic cells both exposing PS. Due to cytoskeleton remodeling PS has a higher lateral mobility on the surfaces of apoptotic cells thereby promoting receptor clustering on the phagocyte. PS not only plays an important role in the engulfment process, but also acts as ‘tolerate me’ signal inducing the release of anti-inflammatory cytokines by phagocytes. An efficient and fast clearance of apoptotic cells is required to prevent secondary necrosis and leakage of intracellular danger signals into the surrounding tissue. Failure or prolongation of the clearance process leads to the release of intracellular antigens into the periphery provoking inflammation and development of systemic inflammatory autoimmune disease like systemic lupus erythematosus. Here we review the current findings concerning apoptosis-inducing pathways, important players of apoptotic cell recognition and clearance as well as the role of membrane remodeling in the engulfment of apoptotic cells by phagocytes. (paper)

Iohexol clearance is superior to creatinine-based renal function estimating equations in detecting short-term renal function decline in chronic heart failure

Science.gov (United States)

Cvan Trobec, Katja; Kerec Kos, Mojca; von Haehling, Stephan; Anker, Stefan D.; Macdougall, Iain C.; Ponikowski, Piotr; Lainscak, Mitja

2015-01-01

Aim To compare the performance of iohexol plasma clearance and creatinine-based renal function estimating equations in monitoring longitudinal renal function changes in chronic heart failure (CHF) patients, and to assess the effects of body composition on the equation performance. Methods Iohexol plasma clearance was measured in 43 CHF patients at baseline and after at least 6 months. Simultaneously, renal function was estimated with five creatinine-based equations (four- and six-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Cockcroft-Gault adjusted for lean body mass, Chronic Kidney Disease Epidemiology Collaboration equation) and body composition was assessed using bioimpedance and dual-energy x-ray absorptiometry. Results Over a median follow-up of 7.5 months (range 6-17 months), iohexol clearance significantly declined (52.8 vs 44.4 mL/[min ×1.73 m2], P = 0.001). This decline was significantly higher in patients receiving mineralocorticoid receptor antagonists at baseline (mean decline -22% of baseline value vs -3%, P = 0.037). Mean serum creatinine concentration did not change significantly during follow-up and no creatinine-based renal function estimating equation was able to detect the significant longitudinal decline of renal function determined by iohexol clearance. After accounting for body composition, the accuracy of the equations improved, but not their ability to detect renal function decline. Conclusions Renal function measured with iohexol plasma clearance showed relevant decline in CHF patients, particularly in those treated with mineralocorticoid receptor antagonists. None of the equations for renal function estimation was able to detect these changes. ClinicalTrials.gov registration number NCT01829880 PMID:26718759

Recent activities on clearance in IAEA and clearance automatic laser inspection system (CLALIS)

International Nuclear Information System (INIS)

Hattori, Takatoshi; Sasaki, Michiya

2005-01-01

Exemption levels for bulk amounts of materials have been described in RS-G-1.7 published as a safety guide in IAEA on August 2004. In Japan, the Nuclear Safety Commission adopted the RS-G-1.7 values as Japanese clearance levels after the careful review of dose assessment results. After completing revises of regulatory laws in relation to clearance level, solid wastes from decommissioning and operating nuclear power plants will be targets of clearance inspection. In CRIEPI, Clearance Automatic Laser Inspection System (CLALIS) has been developed, which can give high reliability and objectivity to the measurement data. The CLALIS is a new monitoring system coupling with 3D laser shape measurement, Monte-Carlo calculation and gamma measurement techniques, which can keep a high accuracy in the measurement data using an automatic correction technique for self-shielding effects of metal waste itself and is expected to apply as a practical use in actual clearance inspections. (author)

Generic clearance values

International Nuclear Information System (INIS)

Bossio, M.C.; Muniz, C.C.

2009-01-01

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)

Generic Clearance Values

International Nuclear Information System (INIS)

Bossio, M.C.; Muniz, C.C.

2010-01-01

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) [es

Changes in glomerular filtration rate, lithium clearance and plasma protein clearances in the early phase after unilateral nephrectomy in living healthy renal transplant donors

DEFF Research Database (Denmark)

Strandgaard, S; Kamper, A; Skaarup, P

1988-01-01

1. Glomerular and tubular function was studied before and 2 months after unilateral nephrectomy in 14 healthy kidney donors by measurement of the clearances of 51Cr-labelled ethylenediaminetetra-acetate, lithium, beta 2-microglobulin, albumin and immunoglobulin G. 2. The glomerular filtration rat...

Novel lanthanide-labeled metal oxide nanoparticles improve the measurement of in vivo clearance and translocation

Directory of Open Access Journals (Sweden)

Abid Aamir D

2013-01-01

Full Text Available Abstract The deposition, clearance and translocation of europium-doped gadolinium oxide nanoparticles in a mouse lung were investigated experimentally. Nanoparticles were synthesized by spray flame pyrolysis. The particle size, crystallinity and surface properties were characterized. Following instillation, the concentrations of particles in organs were determined with inductively coupled plasma mass spectrometry. The protein corona coating the nanoparticles was found to be similar to the coating on more environmentally relevant nanoparticles such as iron oxide. Measurements of the solubility of the nanoparticles in surrogates of biological fluids indicated very little propensity for dissolution, and the elemental ratio of particle constituents did not change, adding further support to the contention that intact nanoparticles were measured. The particles were intratracheally instilled into the mouse lung. After 24 hours, the target organs were harvested, acid digested and the nanoparticle mass in each organ was measured by inductively coupled plasma mass spectrometry (ICP-MS. The nanoparticles were detected in all the studied organs at low ppb levels; 59% of the particles remained in the lung. A significant amount of particles was also detected in the feces, suggesting fast clearance mechanisms. The nanoparticle system used in this work is highly suitable for quantitatively determining deposition, transport and clearance of nanoparticles from the lung, providing a quantified measure of delivered dose.

Identification of the transcripts associated with spontaneous HCV clearance in individuals co-infected with HIV and HCV

Directory of Open Access Journals (Sweden)

Yue Chen

2016-11-01

Full Text Available Abstract Background Infection with human immunodeficiency virus (HIV influences the outcome and natural disease progression of hepatitis C virus (HCV infection. While the majority of HCV mono-infected and HCV/HIV co-infected subjects develop chronic HCV infection, 20–46% of mono- and co-infected subjects spontaneously clear HCV infection. The mechanism underlying viral clearance is not clearly understood. Analysis of differential cellular gene expression (mRNA between HIV-infected patients with persistent HCV infection or spontaneous clearance could provide a unique opportunity to decipher the mechanism of HCV clearance. Methods Plasma RNA from HIV/HCV co-infected subjects who cleared HCV and those who remained chronically infected with HCV was sequenced using Ion Torrent technology. The sequencing results were analyzed to identify transcripts that are associated with HCV clearance by measuring differential gene expression in HIV/HCV co-infected subjects who cleared HCV and those who remained chronically infected with HCV. Results We have identified plasma mRNA, the levels of which are significantly elevated (at least 5 fold, False Discovery Rate (FDR <0.05 before HCV infection in subjects who cleared HCV compared to those who remained chronically infected. Upon further analysis of these differentially expressed genes, before and after HCV infection, we found that before HCV infection 12 genes were uniquely upregulated in the clearance group compared to the chronically infected group. Importantly, a number of these 12 genes and their upstream regulators (such as CCL3, IL17D, LBP, SOCS3, NFKBIL1, IRF are associated with innate immune response functions. Conclusions These results suggest that subjects who spontaneously clear HCV may express these unique genes associated with innate immune functions.

Airway Clearance Techniques (ACTs)

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Full Text Available ... Treatments and Therapies Airway Clearance Airway Clearance Techniques (ACTs) There are different ways to clear your airways. ... or caregiver. Older kids and adults can choose ACTs that they can do on their own. Share ...

Airway Clearance Techniques (ACTs)

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Airway Clearance Techniques (ACTs)

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Airway Clearance Techniques (ACTs)

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Airway Clearance Techniques (ACTs)

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Study on clearance system

International Nuclear Information System (INIS)

Onishi, Yuko; Miura, Hiroshi; Kawasaki, Satoru

2011-01-01

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)

Airway Clearance Techniques (ACTs)

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A Physiologically Based Pharmacokinetic Model to Predict the Pharmacokinetics of Highly Protein-Bound Drugs and Impact of Errors in Plasma Protein Binding

Science.gov (United States)

Ye, Min; Nagar, Swati; Korzekwa, Ken

2015-01-01

Predicting the pharmacokinetics of highly protein-bound drugs is difficult. Also, since historical plasma protein binding data was often collected using unbuffered plasma, the resulting inaccurate binding data could contribute to incorrect predictions. This study uses a generic physiologically based pharmacokinetic (PBPK) model to predict human plasma concentration-time profiles for 22 highly protein-bound drugs. Tissue distribution was estimated from in vitro drug lipophilicity data, plasma protein binding, and blood: plasma ratio. Clearance was predicted with a well-stirred liver model. Underestimated hepatic clearance for acidic and neutral compounds was corrected by an empirical scaling factor. Predicted values (pharmacokinetic parameters, plasma concentration-time profile) were compared with observed data to evaluate model accuracy. Of the 22 drugs, less than a 2-fold error was obtained for terminal elimination half-life (t1/2, 100% of drugs), peak plasma concentration (Cmax, 100%), area under the plasma concentration-time curve (AUC0–t, 95.4%), clearance (CLh, 95.4%), mean retention time (MRT, 95.4%), and steady state volume (Vss, 90.9%). The impact of fup errors on CLh and Vss prediction was evaluated. Errors in fup resulted in proportional errors in clearance prediction for low-clearance compounds, and in Vss prediction for high-volume neutral drugs. For high-volume basic drugs, errors in fup did not propagate to errors in Vss prediction. This is due to the cancellation of errors in the calculations for tissue partitioning of basic drugs. Overall, plasma profiles were well simulated with the present PBPK model. PMID:26531057

Airway Clearance Techniques (ACTs)

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Airway Clearance Techniques (ACTs)

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A Simple Method to Measure Renal Function in Swine by the Plasma Clearance of Iohexol

Science.gov (United States)

Luis-Lima, Sergio; García-Contreras, Consolación; Carrara, Fabiola; Negrín-Mena, Natalia; Jiménez-Sosa, Alejandro; Jiménez-Hernández, Hugo; Porrini, Esteban

2018-01-01

There is no simple method to measure glomerular filtration rate (GFR) in swine, an established model for studying renal disease. We developed a protocol to measure GFR in conscious swine by using the plasma clearance of iohexol. We used two groups, test and validation, with eight animals each. Ten milliliters of iohexol (6.47 g) was injected into the marginal auricular vein and blood samples (3 mL) were collected from the orbital sinus at different points after injection. GFR was determined using two models: two-compartment (CL2: all samples) and one-compartment (CL1: the last six samples). In the test group, CL1 overestimated CL2 by ~30%: CL2 = 245 ± 93 and CL1 = 308 ± 123 mL/min. This error was corrected by a first-order polynomial quadratic equation to CL1, which was considered the simplified method: SM = −47.909 + (1.176xCL1) − (0.00063968xCL12). The SM showed narrow limits of agreement with CL2, a concordance correlation of 0.97, and a total deviation index of 14.73%. Similar results were obtained for the validation group. This protocol is reliable, reproducible, can be performed in conscious animals, uses a single dose of the marker, and requires a reduced number of samples, and avoids urine collection. Finally, it presents a significant improvement in animal welfare conditions and handling necessities in experimental trials. PMID:29329247

A Simple Method to Measure Renal Function in Swine by the Plasma Clearance of Iohexol

Directory of Open Access Journals (Sweden)

Sergio Luis-Lima

2018-01-01

Full Text Available There is no simple method to measure glomerular filtration rate (GFR in swine, an established model for studying renal disease. We developed a protocol to measure GFR in conscious swine by using the plasma clearance of iohexol. We used two groups, test and validation, with eight animals each. Ten milliliters of iohexol (6.47 g was injected into the marginal auricular vein and blood samples (3 mL were collected from the orbital sinus at different points after injection. GFR was determined using two models: two-compartment (CL2: all samples and one-compartment (CL1: the last six samples. In the test group, CL1 overestimated CL2 by ~30%: CL2 = 245 ± 93 and CL1 = 308 ± 123 mL/min. This error was corrected by a first-order polynomial quadratic equation to CL1, which was considered the simplified method: SM = −47.909 + (1.176xCL1 − (0.00063968xCL12. The SM showed narrow limits of agreement with CL2, a concordance correlation of 0.97, and a total deviation index of 14.73%. Similar results were obtained for the validation group. This protocol is reliable, reproducible, can be performed in conscious animals, uses a single dose of the marker, and requires a reduced number of samples, and avoids urine collection. Finally, it presents a significant improvement in animal welfare conditions and handling necessities in experimental trials.

Loss of Acetylcholine Signaling Reduces Cell Clearance Deficiencies in Caenorhabditis elegans.

Directory of Open Access Journals (Sweden)

Sérgio M Pinto

Full Text Available The ability to eliminate undesired cells by apoptosis is a key mechanism to maintain organismal health and homeostasis. Failure to clear apoptotic cells efficiently can cause autoimmune diseases in mammals. Genetic studies in Caenorhabditis elegans have greatly helped to decipher the regulation of apoptotic cell clearance. In this study, we show that the loss of levamisole-sensitive acetylcholine receptor, but not of a typical neuronal acetylcholine receptor causes a reduction in the number of persistent cell corpses in worms suffering from an engulfment deficiency. This reduction is not caused by impaired or delayed cell death but rather by a partial restoration of the cell clearance capacity. Mutants in acetylcholine turn-over elicit a similar phenotype, implying that acetylcholine signaling is the process responsible for these observations. Surprisingly, tissue specific RNAi suggests that UNC-38, a major component of the levamisole-sensitive receptor, functions in the dying germ cell to influence engulfment efficiency. Animals with loss of acetylcholine receptor exhibit a higher fraction of cell corpses positive for the "eat-me" signal phosphatidylserine. Our results suggest that modulation by ion channels of ion flow across plasma membrane in dying cells can influence the dynamics of phosphatidylserine exposure and thus clearance efficiency.

Comparative study for small computer supported clearance determination with 131iodine hippuran using CdTe detectors

International Nuclear Information System (INIS)

Duerr, G.

1986-01-01

With the goal to work out a simple, non-invasive method for the total clearance determination also for immobile patients, we carried out this clearance study with CdTe semi-conductor detectors. The 131 iodine hippuran clearance determination was carried out on 69 patients in the nuclear medicine department of the Radiological Policlinic in the framework of a routine diagnosis with ambulant and stationary patients with a gamma camera and a connecting evaluation system. At the same time we recorded the shoulder curves using two CdTe semi-conductor detectors and deposited the data in a portable semi-conductor memory. Next the hypotheses for the routine use with the inclusion of commercially common small computers was worked out. The plasma disappearance curves which were recorded over the shoulder region were evaluated with a small computer according to the method of the modified Oberhausen tables and the Oberhausen formula. (orig./DG) [de

Clearance Kinetics and Clearance Routes of Molecules From the Suprachoroidal Space After Microneedle Injection.

Science.gov (United States)

Chiang, Bryce; Wang, Ke; Ethier, C Ross; Prausnitz, Mark R

2017-01-01

To determine clearance kinetics and routes of clearance of molecules from the suprachoroidal space (SCS) of live New Zealand White rabbits. Suprachoroidal space collapse rate and pressure changes after microneedle injection into SCS were determined. Fluorescent fundus images were acquired to determine clearance rates of molecules ranging in size from 332 Da to 2 MDa. Microneedle injections of fluorescein were performed, and samples were taken from various sites over time to determine amount of fluorescein exiting the eye. Clearance transport was modeled theoretically and compared with experimental data. After injection, pressures in SCS and vitreous humor spiked and returned to baseline within 20 minutes; there was no difference between these two pressures. Suprachoroidal space collapse occurred within 40 minutes. One hour after fluorescein injection, 46% of fluorescein was still present in the eye, 15% had transported across sclera, 6% had been cleared by choroidal vasculature, and 4% had exited via leakage pathways. Characteristic clearance time increased in proportion with molecular radius, but total clearance of 2 MDa FITC-dextran was significantly slower (21 days) than smaller molecules. These data generally agreed with predictions from a theoretical model of molecular transport. Guided by experimental data in the context of model predictions, molecular clearance from SCS occurred in three regimes: (1) on a time scale of approximately 10 minutes, fluid and molecules exited SCS by diffusion into sclera and choroid, and by pressure-driven reflux via transscleral leakage sites; (2) in approximately 1 hour, molecules cleared from choroid by blood flow; and (3) in 1 to 10 hours, molecules cleared from sclera by diffusion and convection.

Study on clearance system

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

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)

Extrapolation of plasma clearance to understand species differences in toxicokinetics of bisphenol A.

Science.gov (United States)

Poet, Torka; Hays, Sean

2017-10-13

1. Understanding species differences in the toxicokinetics of bisphenol A (BPA) is central to setting acceptable exposure limits for human exposures to BPA. BPA toxicokinetics have been well studied, with controlled oral dosing studies in several species and across a wide dose range. 2. We analyzed the available toxicokinetic data for BPA following oral dosing to assess potential species differences and dose dependencies. BPA is rapidly conjugated and detoxified in all species. The toxicokinetics of BPA can be well described using non-compartmental analyses. 3. Several studies measured free (unconjugated) BPA in blood and reported area under the curve (AUC) of free BPA in blood of mice, rats, monkeys, chimpanzees and humans following controlled oral doses. Extrinsic clearance was calculated and analyzed across species and dose using allometric scaling. 4. The results indicate free BPA clearance is well described using allometric scaling with high correlation coefficients across all species and doses up to 10 mg/kg. The results indicate a human equivalent dose factor (HEDf) of 0.9 is appropriate for extrapolating a point of departure from mice and rats to a human equivalent dose (HED), thereby replacing default uncertainty factors for animal to human toxicokinetics.

Mice lacking prostaglandin E receptor subtype 4 manifest disrupted lipid metabolism attributable to impaired triglyceride clearance.

Science.gov (United States)

Cai, Yin; Ying, Fan; Song, Erfei; Wang, Yu; Xu, Aimin; Vanhoutte, Paul M; Tang, Eva Hoi-Ching

2015-12-01

Upon high-fat feeding, prostaglandin E receptor subtype 4 (EP4)-knockout mice gain less body weight than their EP4(+/+) littermates. We investigated the cause of the lean phenotype. The mice showed a 68.8% reduction in weight gain with diminished fat mass that was not attributable to reduced food intake, fat malabsorption, or increased energy expenditure. Plasma triglycerides in the mice were elevated by 244.9%. The increase in plasma triglycerides was independent of changes in hepatic very low density lipoprotein (VLDL)-triglyceride production or intestinal chylomicron-triglyceride synthesis. However, VLDL-triglyceride clearance was drastically impaired in the EP4-knockout mice. The absence of EP4 in mice compromised the activation of lipoprotein lipase (LPL), the key enzyme responsible for trafficking of plasma triglycerides into peripheral tissues. Deficiency in EP4 reduced hepatic mRNA expression of the transcriptional factor cAMP response element binding protein H (by 36.8%) and LPL activators, including apolipoprotein (Apo)a5 (by 40.2%) and Apoc2 (by 61.3%). In summary, the lean phenotype of EP4-deficient mice resulted from reduction in adipose tissue and accretion of other peripheral organs caused by impaired triglyceride clearance. The findings identify a new metabolic dimension in the physiologic role played by endogenous EP4. © FASEB.

Renal clearance of an ionic high-osmolar and a nonionic low-osmolar contrast medium

International Nuclear Information System (INIS)

Thomsen, H.S.; Vestergaard, A.; Nielsen, S.L.; Fogh-Andersen, N.; Golman, K.; Dorph, S.

1991-01-01

One hundred patients with normal serum creatinine concentration underwent intravenous urography with either an ionic high-osmolar (diatrizoate) or a nonionic low-osmolar (iopamidol) contrast medium after randomization. Before injection of the contrast medium, a blood sample was drawn for determinating serum creatinine concentration, and a urine sample for measurement of urine osmolality. Using x-ray fluorescence, the plasma concentration of iodine (contrast medium) was determined on blood samples drawn approximately 3 and 4 hours after injection of the contrast medium. The glomerular filtration rate was calculated by two different formulas: one requiring only a single sample and one requiring at least two samples (standard). There were poor correlations between the standard contrast medium clearance and the serum creatinine concentration, the estimated creatinine clearance (calculated from a nomogram), as well as the urine osmolality. The 3-hour and the 4-hour single-sample values correlated well with the two-sample values for both contrast media. In patients with normal serum creatinine, the glomerular filtration rate determined by measuring the contrast medium concentration in a single plasma sample obtained at 3 hours, is almost identical to the value determined from two samples. Consequently, two samples are unnecessary

A physiologically based pharmacokinetic model to predict the pharmacokinetics of highly protein-bound drugs and the impact of errors in plasma protein binding.

Science.gov (United States)

Ye, Min; Nagar, Swati; Korzekwa, Ken

2016-04-01

Predicting the pharmacokinetics of highly protein-bound drugs is difficult. Also, since historical plasma protein binding data were often collected using unbuffered plasma, the resulting inaccurate binding data could contribute to incorrect predictions. This study uses a generic physiologically based pharmacokinetic (PBPK) model to predict human plasma concentration-time profiles for 22 highly protein-bound drugs. Tissue distribution was estimated from in vitro drug lipophilicity data, plasma protein binding and the blood: plasma ratio. Clearance was predicted with a well-stirred liver model. Underestimated hepatic clearance for acidic and neutral compounds was corrected by an empirical scaling factor. Predicted values (pharmacokinetic parameters, plasma concentration-time profile) were compared with observed data to evaluate the model accuracy. Of the 22 drugs, less than a 2-fold error was obtained for the terminal elimination half-life (t1/2 , 100% of drugs), peak plasma concentration (Cmax , 100%), area under the plasma concentration-time curve (AUC0-t , 95.4%), clearance (CLh , 95.4%), mean residence time (MRT, 95.4%) and steady state volume (Vss , 90.9%). The impact of fup errors on CLh and Vss prediction was evaluated. Errors in fup resulted in proportional errors in clearance prediction for low-clearance compounds, and in Vss prediction for high-volume neutral drugs. For high-volume basic drugs, errors in fup did not propagate to errors in Vss prediction. This is due to the cancellation of errors in the calculations for tissue partitioning of basic drugs. Overall, plasma profiles were well simulated with the present PBPK model. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Pooled population pharmacokinetic model of imipenem in plasma and the lung epithelial lining fluid.

Science.gov (United States)

van Hasselt, J G Coen; Rizk, Matthew L; Lala, Mallika; Chavez-Eng, Cynthia; Visser, Sandra A G; Kerbusch, Thomas; Danhof, Meindert; Rao, Gauri; van der Graaf, Piet H

2016-06-01

Several clinical trials have confirmed the therapeutic benefit of imipenem for treatment of lung infections. There is however no knowledge of the penetration of imipenem into the lung epithelial lining fluid (ELF), the site of action relevant for lung infections. Furthermore, although the plasma pharmacokinetics (PK) of imipenem has been widely studied, most studies have been based on selected patient groups. The aim of this analysis was to characterize imipenem plasma PK across populations and to quantify imipenem ELF penetration. A population model for imipenem plasma PK was developed using data obtained from healthy volunteers, elderly subjects and subjects with renal impairment, in order to identify predictors for inter-individual variability (IIV) of imipenem PK. Subsequently, a clinical study which measured plasma and ELF concentrations of imipenem was included in order to quantify lung penetration. A two compartmental model best described the plasma PK of imipenem. Creatinine clearance and body weight were included as subject characteristics predictive for IIV on clearance. Typical estimates for clearance, central and peripheral volume, and inter-compartmental clearance were 11.5 l h(-1) , 9.37 l, 6.41 l, 13.7 l h(-1) , respectively (relative standard error (RSE) imipenem into ELF was described using a time-independent penetration coefficient of 0.44 (RSE 14%). The identified lung penetration coefficient confirms the clinical relevance of imipenem for treatment of lung infections, while the population PK model provided insights into predictors of IIV for imipenem PK and may be of relevance to support dose optimization in various subject groups. © 2016 The British Pharmacological Society.

Protein clearance from the air spaces and lungs of unanesthetized sheep over 144 h

International Nuclear Information System (INIS)

Berthiaume, Y.; Albertine, K.H.; Grady, M.; Fick, G.; Matthay, M.A.

1989-01-01

We studied the rate, the routes, and the mechanisms for protein clearance from the air spaces and lungs of 20 unanesthetized sheep over 144 h. We instilled 100 ml of autologous serum labeled with 125I-albumin into one lung. At the end of 24, 48, 96, or 144 h, the lungs were removed and the residual native protein and 125I-albumin in the air spaces were determined by bronchoalveolar lavage. Also the fraction of the instilled 125I-albumin remaining in the rest of the lung was measured in the lung homogenate. Clearance of the 125I-albumin from the lung into the plasma, lymph, thyroid, urine, and feces was also determined. The removal of both the 125I-albumin and the native protein from the air spaces was slow, following a monoexponential decline. The removal rate of the 125I-albumin from the air spaces was slightly but significantly faster (1.6%/h) than the clearance rate of the native protein (0.9%/h). Clearance of the 125I-albumin from the lung also followed a slow monoexponential decline at a rate of 1.4%/h. At all time periods, 75% of the 125I-albumin remaining in the lung was located in the air spaces, thus indicating that the pulmonary epithelium is the principal barrier to protein clearance from the normal lung. Macrophages appeared to play a minor role in alveolar protein clearance because the quantity of 125I-albumin present in the phagocytic cells in the air spaces was less than 1% of the instilled 125I-albumin at all time periods. However, macrophages may play some role in protein clearance after 48 h because we visualized phagolysosomes in macrophages, and there was an increase in free iodine in lung lavage, urine, thyroid, and feces after 48 h. However, gel electrophoretic studies showed that most of the 125I-albumin was cleared from the lung as an intact molecule, although only 24.7 +/- 4.7% of the 125I-albumin was cleared by the lymphatics

Dynamics of formation and resolution of vasogenic brain oedema. 1. Measurement of oedema clearance into ventricular CSF

Energy Technology Data Exchange (ETDEWEB)

Tsuyumu, M; Reulen, H J; Prioleau, G [Mainz Univ. (Germany, F.R.). Neurochirurgische Klinik

1981-01-01

Previous studies showed that resolution of brain oedema may occur by clearance into the CSF. The present study was performed to measure quantitatively the amount of oedema clearance in cold-induced oedema in cats. In order to determine the minute amounts of oedema fluid entering the CSF the oedema fluid was labelled with a high concentration of an extracellular marker (S/sup 35/-sodiumthiosulphate). Ventriculo-cisternal perfusion was used to collect the marker in the cisternal outflow. By using the assumption that oedema fluid has the same marker concentration as the plasma, the distribution profile of extracellular space as well as the clearance rate of oedema into CSF could be computed. Oedema and thiosulphate space were most pronounced in the white matter underlying the cortical cold injury. The values then declined progressively with the distance from the lesion towards the ventricle. Oedema fluid clearance into the ventricular CSF at 24 hours following the cold injury amounted to 0.8-1.2 ..mu..l/min or 1.15 ml/day. These data support the assumption that this may be one of the main mechanisms of the resolution of vasogenic brain oedema.

Clearance of materials from accelerator facilities

Directory of Open Access Journals (Sweden)

Rokni Sayed H.

2017-01-01

Full Text Available A new Technical Standard that supports the clearance of materials and equipment (personal property from U.S. Department of Energy (DOE accelerator facilities has been developed. The Standard focuses on personal property that has the potential to be radiologically impacted by accelerator operations. It addresses material clearance programs and protocols for off-site releases without restriction on use. Common metals with potential volumetric activation are of main interest with technical bases provided in Appendices of the Standard. The clearance protocols in the Standard include three elements: 1 clearance criteria, 2 process knowledge, and 3 measurement methods. This paper presents the technical aspects of the new Standard, discusses operational experience gained in clearance of materials and equipment from several accelerator facilities at SLAC and examples as to how this Standard can be applied to benefit the entirety of the DOE Accelerator Complex.

Multicenter trial validation of a camera-based method to measure Tc-99m mercaptoacetyltriglycine, or Tc-99m MAG3, clearance.

Science.gov (United States)

Taylor, A; Manatunga, A; Morton, K; Reese, L; Prato, F S; Greenberg, E; Folks, R; Kemp, B J; Jones, M E; Corrigan, P E; Galt, J; Eshima, L

1997-07-01

To evaluate an improved camera-based method for calculating the clearance of technetium-99m mercaptoacetyltriglycine (MAG3) in a multicenter trial. Tc-99m MAG3 scintigraphy was performed in 49 patients at three sites in the United States and Canada. The percentage of the injected dose of Tc-99m MAG3 in the kidney at 1-2, 1.0-2.5, and 2-3 minutes after injection was correlated with the plasma-based Tc-99m MAG3 clearances. The data were combined with the results obtained in 20 additional patients in a previously published pilot study. Regression models correlating the plasma-based Tc-99m MAG3 clearance with the percentage uptake in the kidney for each time interval were developed; there was no statistically significant difference among sites in the regression equations. Correction for body surface area statistically significantly (P time interval. For the 1.0-2.5-minute interval, the body surface area-corrected correlation coefficient for the four combined sites was .87, and it improved to .93 when one outlier was omitted from the analysis. Similar results were obtained with the other time intervals. Independent processing by two observers showed no clinically important differences in the percentage dose in the kidney or in relative function. An improved camera-based method to calculate the clearance of Tc-99m MAG3 was validated in a multicenter trial.

Clearance and release from control - An international perspective

International Nuclear Information System (INIS)

Thierfeldt, S.

2005-01-01

This paper tries to give an overview of the clearance, or release from regulatory control, on an international scale, including some of those countries where clearance has become or is about to become vital for D and D. The emphasis lies on the impact of clearance, and in particular of differences between clearance levels of various countries, on D and D. Relevance of clearance for D and D of nuclear installations Clearance is an essential part of waste management (or more general, material management) in nuclear installations, and in particular during the decommissioning phase where waste streams continues to arise. Of course, the relevance of clearance in a particular country depends on a number of factors, like: availability of a final repository and its price; prevailing decommissioning strategy; number of nuclear installations reaching decommissioning phase. This small selection of reasons why clearance may be of varying importance for different countries may already suffice to illustrate why up to now clearance has been developed and implemented in quite different ways. If one thinks of additional reasons that may influence clearance, like politics, the public opinion, availability of funds etc., the situation becomes even more complex. It is, however safe to draw the conclusion that countries with a certain number of nuclear installations which have been or will soon be shut down or which are already in the decommissioning phase will need to implement provisions for clearance. This has indeed been the case with countries like the UK, Germany, the USA, Sweden, and a number of others. It is not essential for clearance levels to be exactly equal between various countries. They may differ as long as the difference is not too large, e.g. the values fall into the same order of magnitude. This is the reason why for example Germany has no problems with clearance levels which differ from the EU recommendation RP 122 partially adopted in a number of EU countries

Lack of influence of CYP2D6 genotype on the clearance of (R)-, (S)- and racemic-methadone

DEFF Research Database (Denmark)

Coller, J K; Joergensen, C; Foster, D J R

2007-01-01

OBJECTIVE: To investigate the influence of CYP2D6 genotype on the oral clearance of (R)-, (S)- and rac-methadone. METHODS: In this retrospective study, CYP2D6 genotypes were identified in 56 methadone maintained subjects. Plasma concentrations of (R)-, (S)- and rac-methadone were determined by st...

Use of specific radioimmunoassays to determine the renal clearance rates of estrone and 17. beta. -estradiol during the menstrual cycle. [Tritium tracer techniques

Energy Technology Data Exchange (ETDEWEB)

Wright, K.; Collins, D.C.; Preedy, J.R.K.

1978-11-01

Specific RIAs requiring ether extraction only were established for estrone and 17..beta..-estradiol both in plasma and in urine from the nonpregnant female. These assays were used to measure the renal clearance rates of estrone and of 17..beta..-estradiol in eight ambulatory women in the follicular and in the luteal phases of the menstrual cycle. The mean (+-SE) for the renal clearance rate of estrone was 0.71 +- 0.058 ml/min in the follicular phase and 1.26 +- 0.35 ml/min in the luteal phase. The mean (+-SE) renal clearance rate of 17..beta..-estradiol was 0.44 +- 0.055 ml/min in the follicular phase and 0.29 +- 0.043 ml/min in the luteal phase. There was no significant difference in the renal clearance rates of either estrone or of 17..beta..-estradiol between the follicular and luteal phases of the cycle. The renal clearances of estrone and 17..beta..-estradiol were highly correlated (r = 0.84; P < 0.01). The renal clearance rate of estrone was significantly greater than that of 17..beta..-estradiol in both phases of the cycle (P < 0.01).

Anatomical and physiological basis for the allometric scaling of cisplatin clearance in dogs.

Science.gov (United States)

Achanta, S; Sewell, A; Ritchey, J W; Broaddus, K; Bourne, D W A; Clarke, C R; Maxwell, L K

2016-06-01

Cisplatin is a platinum-containing cytotoxic drug indicated for the treatment of solid tumors in veterinary and human patients. Several of the algorithms used to standardize the doses of cytotoxic drugs utilize allometry, or the nonproportional relationships between anatomical and physiological variables, but the underlying basis for these relationships is poorly understood. The objective of this proof of concept study was to determine whether allometric equations explain the relationships between body weight, kidney weight, renal physiology, and clearance of a model, renally cleared anticancer agent in dogs. Postmortem body, kidney, and heart weights were collected from 364 dogs (127 juveniles and 237 adults, including 51 dogs ≥ 8 years of age). Renal physiological and cisplatin pharmacokinetic studies were conducted in ten intact male dogs including two juvenile and eight adult dogs (4-55 kg). Glomerular filtration rate (GFR), effective renal plasma flow, effective renal blood flow, renal cisplatin clearance, and total cisplatin clearance were allometrically related to body weight with powers of 0.75, 0.59, 0.61, 0.71, and 0.70, respectively. The similar values of these diverse mass exponents suggest a common underlying basis for the allometry of kidney size, renal physiology, and renal drug handling. © 2015 John Wiley & Sons Ltd.

Rational customs clearance technology choice

OpenAIRE

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.

7 CFR 1927.55 - Title clearance services.

Science.gov (United States)

2010-01-01

... REGULATIONS TITLE CLEARANCE AND LOAN CLOSING Real Estate Title Clearance and Loan Closing § 1927.55 Title clearance services. (a) Responsibilities of closing agents. Services to be provided to the agency and the borrower by a closing agent in connection with the transaction vary depending on whether a title insurance...

Relationship between silicon concentration and creatinine clearance

International Nuclear Information System (INIS)

Miura, Y.; Nakai, K.; Itoh, C.; Horikiri, J.; Sera, K.; Sato, M.

1998-01-01

Silicon levels in dialysis patients are markedly increasing. Using PIXE we determined the relationship between silicon concentration and creatinine clearance in 30 samples. Urine silicon concentration were significantly correlated to creatinine clearance (p<0.001). And also serum silicon concentration were significantly correlated to creatinine clearance (p<0.0001). (author)

Compressor airfoil tip clearance optimization system

Science.gov (United States)

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.

Noninvasive determination of individual renal clearance

International Nuclear Information System (INIS)

Chanard, J.; Brunois, J.P.; Ruiz, J.C.; Assailly, J.

1980-01-01

A noninvasive method for measurement of individual renal clearance is presented, based on analysis of the early rise of the kidneys' time-activity curves after injection of an appropriate tracer ( 131 I-ortho-iodohippurate for tubular function or 111 In DTPA for glomerular clearance). The analysis is based on the assumption that an insignificant amount of tracer leaves the kidney during the first few moments following injection. Therefore, the kidney activity during this period is directly proportional to the integral of the blood (heart) activity. After blood background subtraction, the linear correlation between the early part of the renogram and the corresponding blood integral activity curve allows calculation of an angular coefficient. The ratio of these coefficients calculated for each kidney is proportional to the ratio of the individual clearances. The latter are calculated from the total clearance simultaneously measured using a simplified method without urine collection. In control subjects with normal renal function individual renal clearances were not significantly different. In uninephrectomized patients a precision of 5% in calculating individual clearance was estimated from data recorded at the level of the remaining kidney. In patients with functional asymmetry, results were compared with 197 HgCl 2 quantitative renal fixation. A linear correlation was found (r = 0.95). The method we propose seems valuable for clinical investigation and allows sequential measurements. (orig.)

Hepatobiliary Clearance Prediction: Species Scaling From Monkey, Dog, and Rat, and In Vitro-In Vivo Extrapolation of Sandwich-Cultured Human Hepatocytes Using 17 Drugs.

Science.gov (United States)

Kimoto, Emi; Bi, Yi-An; Kosa, Rachel E; Tremaine, Larry M; Varma, Manthena V S

2017-09-01

Hepatobiliary elimination can be a major clearance pathway dictating the pharmacokinetics of drugs. Here, we first compared the dose eliminated in bile in preclinical species (monkey, dog, and rat) with that in human and further evaluated single-species scaling (SSS) to predict human hepatobiliary clearance. Six compounds dosed in bile duct-cannulated (BDC) monkeys showed biliary excretion comparable to human; and the SSS of hepatobiliary clearance with plasma fraction unbound correction yielded reasonable predictions (within 3-fold). Although dog SSS also showed reasonable predictions, rat overpredicted hepatobiliary clearance for 13 of 24 compounds. Second, we evaluated the translatability of in vitro sandwich-cultured human hepatocytes (SCHHs) to predict human hepatobiliary clearance for 17 drugs. For drugs with no significant active uptake in SCHH studies (i.e., with or without rifamycin SV), measured intrinsic biliary clearance was directly scalable with good predictability (absolute average fold error [AAFE] = 1.6). Drugs showing significant active uptake in SCHH, however, showed improved predictability when scaled based on extended clearance term (AAFE = 2.0), which incorporated sinusoidal uptake along with a global scaling factor for active uptake and the canalicular efflux clearance. In conclusion, SCHH is a useful tool to predict human hepatobiliary clearance, whereas BDC monkey model may provide further confidence in the prospective predictions. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

A model of clearance rate regulation in mussels

Science.gov (United States)

Fréchette, Marcel

2012-10-01

Clearance rate regulation has been modelled as an instantaneous response to food availability, independent of the internal state of the animals. This view is incompatible with latent effects during ontogeny and phenotypic flexibility in clearance rate. Internal-state regulation of clearance rate is required to account for these patterns. Here I develop a model of internal-state based regulation of clearance rate. External factors such as suspended sediments are included in the model. To assess the relative merits of instantaneous regulation and internal-state regulation, I modelled blue mussel clearance rate and growth using a DEB model. In the usual standard feeding module, feeding is governed by a Holling's Type II response to food concentration. In the internal-state feeding module, gill ciliary activity and thus clearance rate are driven by internal reserve level. Factors such as suspended sediments were not included in the simulations. The two feeding modules were compared on the basis of their ability to capture the impact of latent effects, of environmental heterogeneity in food abundance and of physiological flexibility on clearance rate and individual growth. The Holling feeding module was unable to capture the effect of any of these sources of variability. In contrast, the internal-state feeding module did so without any modification or ad hoc calibration. Latent effects, however, appeared transient. With simple annual variability in temperature and food concentration, the relationship between clearance rate and food availability predicted by the internal-state feeding module was quite similar to that observed in Norwegian fjords. I conclude that in contrast with the usual Holling feeding module, internal-state regulation of clearance rate is consistent with well-documented growth and clearance rate patterns.

Human plasma concentrations of tolbutamide and acetaminophen extrapolated from in vivo animal pharmacokinetics using in vitro human hepatic clearances and simple physiologically based pharmacokinetic modeling for radio-labeled microdose clinical studies

International Nuclear Information System (INIS)

Yamazaki, Hiroshi; Kunikane, Eriko; Nishiyama, Sayako; Murayama, Norie; Shimizu, Makiko; Sugiyama, Yuichi; Chiba, Koji; Ikeda, Toshihiko

2015-01-01

The aim of the current study was to extrapolate the pharmacokinetics of drug substances orally administered in humans from rat pharmacokinetic data using tolbutamide and acetaminophen as model compounds. Adjusted animal biomonitoring equivalents from rat studies based on reported plasma concentrations were scaled to human biomonitoring equivalents using known species allometric scaling factors. In this extrapolation, in vitro metabolic clearance data were obtained using liver preparations. Rates of tolbutamide elimination were roughly similar in rat and human liver microsome experiments, but acetaminophen elimination by rat liver microsomes and cytosolic preparations showed a tendency to be faster than those in humans. Using a simple physiologically based pharmacokinetic (PBPK) model, estimated human plasma concentrations of tolbutamide and acetaminophen were consistent with reported concentrations. Tolbutamide cleared in a roughly similar manner in humans and rats, but medical-dose levels of acetaminophen cleared (dependent on liver metabolism) more slowly from plasma in humans than it did in rats. The data presented here illustrate how pharmacokinetic data in combination with a simple PBPK model can be used to assist evaluations of the pharmacological/toxicological potential of new drug substances and for estimating human radiation exposures from radio-labeled drugs when planning human studies. (author)

Predicting Human Clearance of OATP substrates using Cynomolgus monkey: In vitro-in vivo scaling of hepatic uptake clearance.

Science.gov (United States)

de Bruyn, Tom; Ufuk, Ayse; Cantrill, Carina; Kosa, Rachel E; Bi, Yi-An; Niosi, Mark; Modi, Sweta; Rodrigues, A David; Tremaine, Larry M; Varma, Manthena Vs; Galetin, Aleksandra; Houston, J Brian

2018-05-02

This work explores the utility of the cynomolgus monkey as a preclinical model to predict hepatic uptake clearance mediated by organic anion transporting polypeptide (OATP) transporters. Nine OATP substrates (rosuvastatin, pravastatin, repaglinide, fexofenadine, cerivastatin, telmisartan, pitavastatin, bosentan and valsartan) were investigated in plated cynomolgus monkey and human hepatocytes. Total uptake clearance and passive diffusion were measured in vitro from initial rates in the absence and presence of the OATP inhibitor rifamycin SV, respectively. Total uptake clearance values in plated hepatocytes ranged over three orders of magnitude in both species with a similar rank order and good agreement in the relative contribution of active transport to total uptake between cynomolgus monkey and human. In vivo hepatic clearance for these nine drugs was determined in cynomolgus monkey after intravenous dosing. Hepatic clearances showed a similar range to human parameters and good predictions from respective hepatocyte parameters (with 2.7 and 3.8-fold bias on average, respectively). The use of cross species empirical scaling factors (based on either dataset average or individual drug scaling factor from cynomolgus monkey data) improved prediction (less bias, better concordance) of human hepatic clearance from human hepatocyte data alone. In vitro intracellular binding in hepatocytes also correlated well between species. It is concluded that the minimal species differences observed for the current dataset between cynomolgus monkey and human hepatocyte uptake, both in vitro and in vivo, support future use of this preclinical model to delineate drug hepatic uptake and enable prediction of human in vivo intrinsic hepatic clearance. The American Society for Pharmacology and Experimental Therapeutics.

Assessment of glomerular filtration rate and effective renal plasma flow in cystic fibrosis

International Nuclear Information System (INIS)

Spino, M.; Chai, R.P.; Isles, A.F.; Balfe, J.W.; Brown, R.G.; Thiessen, J.J.; MacLeod, S.M.

1985-01-01

A study was conducted to examine renal function in 10 healthy control subjects and eight patients with cystic fibrosis in stable condition. Sequential bolus injections of /sup 99m/Tc-DTPA and 125 I-OIH were administered to assess glomerular filtration rate and effective renal plasma flow, respectively. Blood was subsequently collected for 3 hours, and urine for 24 hours. Renal clearances of both radioisotope markers were virtually identical in patients and controls. Inasmuch as neither glomerular filtration rate nor effective renal plasma flow was enhanced in patients with cystic fibrosis, increased clearance of drugs in these patients is unlikely to be the result of enhanced glomerular filtration or tubular secretion

48 CFR 801.602-76 - Business clearance review.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Business clearance review... GENERAL DEPARTMENT OF VETERANS AFFAIRS ACQUISITION REGULATION SYSTEM Career Development, Contracting Authority, and Responsibilities 801.602-76 Business clearance review. (a) A business clearance review is a...

Estimation of 131I hippuran clearance during pregnancy

International Nuclear Information System (INIS)

Voigt, R.; Stoll, W.; Zenner, I.; Arndt, J.; Friedrich-Schiller-Univ., Jena

1979-01-01

Changes in 131 I hippuran clearance were estimated by a non-catheter method, as well as total clearance and clearance of each kidney, in 43 women at various stages of pregnancy and in 13 non-pregnant women who were not using hormonal contraceptives. The results are demonstrated in graph form. The methods used are described in detail. The procedure for determining clearance in separate kidneys is indicated. It was found that clearance values increased up to the 35th and 26th weeks of pregnancy. The difference between the sides that were found corresponds with the previously known difference in the function of the right and left kidneys and ureters. (orig.) [de

Comparison of clearance and arteriovenous extraction techniques for measurements of renal hemodynamic functions

International Nuclear Information System (INIS)

Katzberg, R.W.; Pabico, R.C.; Morris, T.W.; Hayakawa, K.; McKenna, B.A.; Ventura, J.A.; Fischer, H.W.

1986-01-01

No previous studies have directly compared timed urine collections (UV/P) vs. arteriovenous (A-V) extraction methods for determination of renal function in whole kidney preparations. We examined different markers and techniques for assessing renal plasma flow (RPF), filtration fraction (FF), and glomerular filtration rate (GFR) in both steady-state and rapidly changing conditions following 2 ml/kg bolus intravenous injections of either Renografin 76% (meglumine/sodium diatrizoate-76%) or hypertonic mannitol 25%. During steady-state conditions, excellent correlations were obtained when comparing markers and techniques. Thus, timed urinary clearances of inulin vs. 99m-technetium DTPA (Tc) had a correlation coefficient (R) of .96 (P less than .01; n = 16), and the A-V extraction technique of inulin vs. Tc as determinants of GFR showed a correlation of R = .98 (P less than .01; n = 15). The timed urinary clearance of inulin vs. the A-V extraction of inulin for glomerular filtration gave a correlation of R = .93 (P less than .01; n = 15). The clearance of para-aminohippurate (PAH) divided by the extraction of PAH vs. flow determinations using the electromagnetic flowmeter gave a correlation of R = .92 (P less than .01; n = 16). The anticipated decrease in GFR following contrast medium and hypertonic mannitol was observed using the A-V extraction technique, whereas an artifactual, exaggerated increase in GFR was observed using the timed urine collection technique. Similarly, we noted an exaggerated increase in RPF using CPAH/EPAH as the methodology. We conclude that rapid changes in renal hemodynamics may be measured accurately using the A-V extraction technique but not with clearance techniques requiring timed urine collections

Role of cellular oxalate in oxalate clearance of patients with calcium oxalate monohydrate stone formation and normal controls.

Science.gov (United States)

Oehlschläger, Sven; Fuessel, Susanne; Meye, Axel; Herrmann, Jana; Froehner, Michael; Albrecht, Steffen; Wirth, Manfred P

2009-03-01

To examine the cellular, plasma, and urinary oxalate and erythrocyte oxalate flux in patients with calcium oxalate monohydrate (COM) stone formation vs normal controls. Pathologic oxalate clearance in humans is mostly integrated in calcium oxalate stone formation. An underlying cause of deficient oxalate clearance could be defective transmembrane oxalate transport, which, in many tissues, is regulated by an anion exchanger (SLC26). We studied 2 groups: 40 normal controls and 41 patients with COM stone formation. Red blood cells were divided for cellular oxalate measurement and for resuspension in a buffered solution (pH 7.40); 0.1 mmol/L oxalate was added. The supernatant was measured for oxalate immediately and 1 hour after incubation. The plasma and urinary oxalate were analyzed in parallel. The mean cellular oxalate concentrations were significantly greater in the normal controls (5.25 +/- 0.47 micromol/L) than in those with COM stone formation (2.36 +/- 0.28 micromol/L; P stone formation (0.31 +/- 0.02 mmol/L) than in the controls (0.24 +/- 0.02 mmol/L; P r = 0.49-0.63; P r = -0.29-0.41; P r = -0.30; P r = 0.25; P stone formation. Our data implicate the presence of a cellular oxalate buffer to stabilize plasma and urinary oxalate concentrations in normal controls.

A comparison of two nuclear-medical techniques for effective renal plasma flow determination in rabbits: Radiation controlled infusion-pump and whole-body measurement according to Oberhausen

International Nuclear Information System (INIS)

Mayer-Wehrstein, R.

1981-01-01

Two nuclear techniques were investigated for determination of the effective renal plasma flow with J-131-Hippuran in rabbits: whole-body measurement according to Oberhausen and clearance determination with a radiation controlled feed back infusion pump. In the first method the clearance determination follows after a single injection of the testing substance in the decreasing phase of the blood level, in the second method a constant blood level of the testing substance is maintained. A technique was developed for the determination of the blood-tissue ratio by considering the values determined by the constant blood level. This way the exact clearance values were computet for the decreasing plasma level. Nineteen clearance determinations were performed in rabbits altogether. (orig.) [de

Establishing exemption and clearance criteria by the regulatory authority

International Nuclear Information System (INIS)

Salih, A.E.A.

2012-04-01

This Project work discusses the relationship between the concepts of exemption and clearance, and their practical use in the overall scheme of regulatory control of practices. It also discusses how exemptions and clearance is established and the scope of its applications for regulatory control. The concept of general clearance levels for any type of material and any possible pathway of disposal is also introduced in this work. Guidance of the Group of Experts establishing scenarios for general clearance, parameter values, and a nuclide-specific list of calculated clearance levels is also presented. Regulatory authorities are required to develop guidance on exemption and clearance levels to assist licensees and registrants to know which practices and sources within practices are exempted from regulatory control and those to be cleared from further controls. Exemption and clearance levels are tools for assisting the Regulatory Authority to optimize the use of resources. (author)

RENAL CLEARANCE AND URINARY EXCRETION OF KANAMYCIN IN DOMESTIC RUMINANT SPECIES

Directory of Open Access Journals (Sweden)

I. JAVED, Z. U. RAHMAN, F. H. KHAN, F. MUHAMMAD, Z. IQBAL AND B. ASLAM

2006-01-01

Full Text Available Species dependent geonetical differences in renal clearance and urinary excretion of kanamycin were investigated in adult female buffaloes, cows, sheep and goats. The drug was administered as a single intravenous dose (5 mg/kg b.wt. Blood and urine samples were collected at various time intervals after drug administration. The plasma and urine concentrations of the drug were determined using the microbiological assay. The mean (± SE values for endogenous creatinine clearance (an index of glomerular filtration rate were 0.77 ± 0.05, 0.49 ± 0.07, 0.81 ± 0.07 and 0.98 ± 0.13 ml/min.kg in buffaloes, cows, sheep and goats, respectively. Experiments regarding kidney handling of kanamycin in these ruminant species revealed respective values of renal clearance as 0.08 ± 0.01, 0.07 ± 0.01, 0.19 ± 0.02 and 0.23 ± 0.04 ml/min.kg. Besides glomerular filtration, kanamycin was reabsorbed from the renal tubules of all ruminant species and actively secreted into the renal tubules of buffaloes and goats. The cumulative percentages of intravenous dose of kanamycin excreted through urine during 12 hours in buffaloes, cows, sheep and goats were 4.31 ± 0.37, 2.53 ± 0.30, 11.0 ± 1.04 and 15.8 ± 2.22, respectively. This species variation in the percentage of urinary excretion in these domestic ruminants coincides with their respective glomerular filtration rates, being the highest in goats, lowest in cows and intermediate in sheep and buffaloes.

14 CFR 1260.63 - Customs clearance and visas.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Customs clearance and visas. 1260.63 Section 1260.63 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.63 Customs clearance and visas. Customs Clearance and Visas (For...

Increased dependence of leucine in posttraumatic sepsis: leucine/tyrosine clearance ratio as an indicator of hepatic impairment in septic multiple organ failure syndrome.

Science.gov (United States)

Pittiruti, M; Siegel, J H; Sganga, G; Coleman, B; Wiles, C E; Belzberg, H; Wedel, S; Placko, R

1985-09-01

The body clearance of 10 plasma amino acids (AA) was determined from the rate of compared muscle-released AA and AA administered by infusion of total parenteral nutrition (TPN) compared to their estimated extracellular (ECW) pool in patients with multiple trauma with (n = 10) or without (n = 16) sepsis at 8-hour intervals. In both nonseptic and septic trauma, increasing TPN increased the mean clearance rate of all infused AA. When the individual AA clearance rates were normalized by the total AA infusion rate, regression-covariance analysis revealed that patients with sepsis had relatively impaired clearances of alanine (p less than 0.01) and methionine, proline, phenylalanine, and tyrosine p less than 0.05 for all). In contrast, the clearances of branched-chain AA (BCAA) valine and isoleucine were maintained, and the clearance of leucine was higher (p less than 0.05) in trauma patients with sepsis than in those without. At any AA infusion rate, compared with surviving patients with sepsis (p less than 0.05), patients who developed fatal multiple organ failure syndrome (MOFS) showed increased clearances of all BCAA with further impaired clearance of tyrosine. The clearance ratio of leucine/tyrosine was increased in MOFS at any AA infusion rate (p less than 0.0001), was an indicator of severity, and, if persistent, was a manifestation of a fatal outcome. Because tyrosine metabolism occurs almost entirely in the liver while leucine can be utilized by viscera and muscle, these data suggest early and progressive septic impairment of the pattern of hepatic uptake and oxidation of AA with a greater body dependence on BCAA, especially leucine, as septic MOFS develops.

Plasma clearance and biodistribution of oxidatively modified 99mTc-ß-VLDL in rabbits

Directory of Open Access Journals (Sweden)

Silva E.L.

1997-01-01

Full Text Available The biodistribution and removal from plasma (measured as fractional clearance rate, FCR, per hour of native and oxidatively modified 99mtechnetium-labeled ß-very low density lipoprotein (99mTc-ß-VLDL were investigated in hypercholesterolemic (HC and control (C three-month old New Zealand rabbits. The intracellular accumulation of ß-VLDL labeled with 99mTc was studied in vitro in THP-1 cells and monocyte-derived macrophages isolated from rabbits. After intravenous injection into C rabbits, copper-oxidized ß-VLDL (99mTc-ox-ß-VLDL was cleared from the circulation faster (0.362 ± 0.070/h than native ß-VLDL (99mTc-nat-ß-VLDL, 0.241 ± 0.070/h. In contrast, the FCR of 99mTc-ox-ß-VLDL in HC rabbits was lower (0.100 ± 0.048/h than that of 99mTc-nat-ß-VLDL (0.163 ± 0.043/h. The hepatic uptake of radiolabeled lipoproteins was lower in HC rabbits (0.114 ± 0.071% injected dose/g tissue for 99mTc-nat-ß-VLDL and 0.116 ± 0.057% injected dose/g tissue for 99mTc-ox-ß-VLDL than in C rabbits (0.301 ± 0.113% injected dose/g tissue for 99mTc-nat-ß-VLDL and 0.305 ± 0.149% injected dose/g tissue for 99mTc-ox-ß-VLDL. The uptake of 99mTc-nat-ß-VLDL and 99mTc-ox-ß-VLDL by atherosclerotic aorta lesions isolated from HC rabbits (99mTc-nat-ß-VLDL: 0.033 ± 0.012% injected dose/g tissue and 99mTc-ox-ß-VLDL: 0.039 ± 0.017% injected dose/g tissue was higher in comparison to that of non-atherosclerotic aortas from C rabbits (99mTc-nat-ß-VLDL: 0.023 ± 0.010% injected dose/g tissue and 99mTc-ox-ß-VLDL: 0.019 ± 0.010% injected dose/g tissue. However, 99mTc-nat-ß-VLDL and 99mTc-ox-ß-VLDL were taken up by atherosclerotic lesions at similar rates. In vitro studies showed that both monocyte-derived macrophages isolated from rabbits and THP-1 macrophages significantly internalized more 99mTc-ox-ß-VLDL than 99mTc-nat-ß-VLDL. These results indicate that in cholesterol-fed rabbits 99mTc-ox-ß-VLDL is slowly cleared from plasma and accumulates in

Plasma adrenaline kinetics in type 1 (insulin-dependent) diabetic patients with and without autonomic neuropathy

DEFF Research Database (Denmark)

Dejgaard, A; Hilsted, J; Henriksen, Jens Henrik Sahl

1989-01-01

Plasma adrenaline kinetics (clearance, extraction across the forearm, initial plasma disappearance rate, mean sojourn time, volume of distribution) were studied in sixteen Type 1 (insulin-dependent) diabetic patients during constant i.v. infusion of tritium labelled adrenaline. In patients with (n...... = 8) and without (n = 8) neuropathy forearm venous plasma noradrenaline and adrenaline concentrations as well as plasma clearance of adrenaline based on arterial sampling (1.7 vs 2.1 l/min) were not significantly different. The initial disappearance time (T 1/2) after the infusion of the tritium...... labelled adrenaline had been stopped was significantly prolonged in Type 1 diabetic patients with neuropathy compared to those without (after 20 min infusion 2.7 vs 2.2 min, p less than 0.02, after 75 min infusion 3.7 vs 2.9 min, p less than 0.05). The corresponding values for the mean sojourn time...

Clearance Laboratory - Capability and measurement sensitivity

Energy Technology Data Exchange (ETDEWEB)

Hedemann Jensen, P.; Lauridsen, B.; Silva, J.; Soegaard-Hansen, J.; Warming, L.

2005-08-01

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)

Clearance Laboratory - Capability and measurement sensitivity

International Nuclear Information System (INIS)

Hedemann Jensen, P.; Lauridsen, B.; Silva, J.; Soegaard-Hansen, J.; Warming, L.

2005-09-01

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)

Lithium clearance in chronic nephropathy

DEFF Research Database (Denmark)

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...... 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...

Experience and lessons learnt from clearance in Germany

International Nuclear Information System (INIS)

Thierfeldt, Stefan

2002-01-01

Clearance is an important corner-stone of waste management in nuclear installations in Germany. It has been practised successfully for around two decades. The importance of clearance can also be judged from the fact that it has been included detailedly in the new German Radiation Protection Ordinance. Currently, there are 19 NPPs and a number of fuel cycle installations in operation in Germany. The main waste quantities, however, arise from the dismantling of NPPs and fuel cycle installations which are currently in decommissioning. As most of the decommissioning projects are targeted for early dismantling instead of safe enclosure, there is already considerable experience with the application of clearance procedures and verification of clearance levels. The German waste management strategy is governed by two options: Clearance of the material (after decontamination and release measurement). After clearance, the material is no longer regarded as radioactive in a legal sense. Final disposal of the material as radioactive waste in a deep geological repository (no near-surface disposal facilities exist or are planned in Germany). A deep geological repository is planned to be operable around 2030. Stefan Thierfeldt described German clearance requirements and lessons learned from their application to decommissioning of power reactors. The great majority of the waste was in fact recycled, although the costs were dominated by the small fraction that had to be disposed of as radioactive waste. Among the lessons learned from the German experience were some revealing insights into the public perception of both clearance and of recycling of material from decommissioning of a nuclear installation

19 CFR 122.26 - Entry and clearance.

Science.gov (United States)

2010-04-01

... AIR COMMERCE REGULATIONS Private Aircraft § 122.26 Entry and clearance. Private aircraft, as defined... information as set forth in § 122.22(c), and grants electronic clearance via electronic mail or telephone...

Plasma kinetics of 125I beta endorphin turnover in lean and obese Zucker rats

International Nuclear Information System (INIS)

Rodd, D.; Caston, A.L.; Green, M.H.; Farrell, P.A.

1990-01-01

Plasma clearance kinetics for Beta Endorphin (BEP) are not well-defined and no definitive data exist for lean versus obese animals. To determine such kinetic parameters, a bolus of 125 I BEP (1μCi/kg) was infused into awake lean(L) and obese(O) Zucker rats. Arterial blood samples were withdrawn initially at 20 seconds intervals and less frequently as a 3-hour experimental period progressed. Donor rat blood was infused (venous catheter) to replace withdrawn blood. At 180 minutes approximately 10% of the initial dose remained in the plasma. Clearance kinetics for 125 I BEP were analyzed by compartmental analysis. A 3-component equation (i.e., 3 compartment model) provided the best fit for both L and O groups. Plasma transit times were very rapid; however, plasma fractional catabolic rate was low. Plasma mean residence time was similar for both groups (50 minutes) as was recycle time. These data suggest that BEP kinetics are similar in L and O rats, and that this peptide may undergo extensive recycling into and out of the plasma compartment. The identity of the other two compartments requires further investigation

Clearance systems in the brain—implications for Alzheimer disease

Science.gov (United States)

Tarasoff-Conway, Jenna M.; Carare, Roxana O.; Osorio, Ricardo S.; Glodzik, Lidia; Butler, Tracy; Fieremans, Els; Axel, Leon; Rusinek, Henry; Nicholson, Charles; Zlokovic, Berislav V.; Frangione, Blas; Blennow, Kaj; Ménard, Joël; Zetterberg, Henrik; Wisniewski, Thomas; de Leon, Mony J.

2015-01-01

Accumulation of toxic protein aggregates—amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles—is the pathological hallmark of Alzheimer disease (AD). Aβ accumulation has been hypothesized to result from an imbalance between Aβ production and clearance; indeed, Aβ clearance seems to be impaired in both early and late forms of AD. To develop efficient strategies to slow down or halt AD, it is critical to understand how Aβ is cleared from the brain. Extracellular Aβ deposits can be removed from the brain by various clearance systems, most importantly, transport across the blood–brain barrier. Findings from the past few years suggest that astroglial-mediated interstitial fluid (ISF) bulk flow, known as the glymphatic system, might contribute to a larger portion of extracellular Aβ (eAβ) clearance than previously thought. The meningeal lymphatic vessels, discovered in 2015, might provide another clearance route. Because these clearance systems act together to drive eAβ from the brain, any alteration to their function could contribute to AD. An understanding of Aβ clearance might provide strategies to reduce excess Aβ deposits and delay, or even prevent, disease onset. In this Review, we describe the clearance systems of the brain as they relate to proteins implicated in AD pathology, with the main focus on Aβ. PMID:26195256

Clearance systems in the brain-implications for Alzheimer disease.

Science.gov (United States)

Tarasoff-Conway, Jenna M; Carare, Roxana O; Osorio, Ricardo S; Glodzik, Lidia; Butler, Tracy; Fieremans, Els; Axel, Leon; Rusinek, Henry; Nicholson, Charles; Zlokovic, Berislav V; Frangione, Blas; Blennow, Kaj; Ménard, Joël; Zetterberg, Henrik; Wisniewski, Thomas; de Leon, Mony J

2015-08-01

Accumulation of toxic protein aggregates-amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles-is the pathological hallmark of Alzheimer disease (AD). Aβ accumulation has been hypothesized to result from an imbalance between Aβ production and clearance; indeed, Aβ clearance seems to be impaired in both early and late forms of AD. To develop efficient strategies to slow down or halt AD, it is critical to understand how Aβ is cleared from the brain. Extracellular Aβ deposits can be removed from the brain by various clearance systems, most importantly, transport across the blood-brain barrier. Findings from the past few years suggest that astroglial-mediated interstitial fluid (ISF) bulk flow, known as the glymphatic system, might contribute to a larger portion of extracellular Aβ (eAβ) clearance than previously thought. The meningeal lymphatic vessels, discovered in 2015, might provide another clearance route. Because these clearance systems act together to drive eAβ from the brain, any alteration to their function could contribute to AD. An understanding of Aβ clearance might provide strategies to reduce excess Aβ deposits and delay, or even prevent, disease onset. In this Review, we describe the clearance systems of the brain as they relate to proteins implicated in AD pathology, with the main focus on Aβ.

Secretin enhances [14C]erythritol clearance in unanesthetized dogs

International Nuclear Information System (INIS)

Lewis, M.H.; Baker, A.L.; Dhorajiwala, J.; Moossa, A.R.

1982-01-01

To determine the effect of secretin infusion on clearance of inert markers into bile, unanesthetized dogs fitted with Thomas cannulas received continuous infusions of [ 14 C]erythritol and [ 3 H]inulin throughout study. Taurocholic acid administered sequentially at 9.0, 20.0, and 40.0 mumol/min enhanced [ 14 C]erythritol clearance, and GIH secretin (3 units/min) administered along with TCA (40.0 mumol/min) increased [ 14 C]erythritol clearance from 4.9 +/- 1.2 ml/10 min to 6.8 +/- 1.3 ml/10 min (P less than 0.001), but simultaneously measured [ 3 H]inulin clearance was unaltered. Secretin alone also increased [ 14 C]erythritol clearance but did not alter [ 3 H]inulin clearance. The increase in [ 14 C]erythritol clearance per unit increase in bile flow was less during secretin infusion than TCA. Thus, secretin increases [ 14 C]erythritol transport through restricted channels, probably distal to the canaliculi. [ 14 C]Erythritol may not be an accurate marker for canalicular bile flow in dogs during secretin infusion

Comparative quantitative evaluation of hepatic clearance of diethyl-IDA and para-butyl-IDA in jaundiced and non-jaundiced patients

International Nuclear Information System (INIS)

Tarolo, G.L.; Picozzi, R.; Palagi, B.; Cammelli, F.; Ospedale di Saronno

1981-01-01

A method for comparative measurement of hepatic clearance of different hepatobiliary agents is described and the clinical use of diethyl-IDA and parabutyl-IDA is discussed. The study was performed with both radiopharmaceuticals in 13 patients with hepatobiliary disease with serum bilirubin ranging from 0.3 to 16.4 mg/100 ml. Diethyl-IDA is preferable for a qualitative evaluation of hepatobiliary disease because of its higher hepatic clearance and faster biliary excretion rate. Parabutyl-IDA is superior for measuring the hepatocytic uptake function, due to the low urinary excretion and the absence of an apparent re-entry from liver to plasma, even in patients with obstructive jaundice. In contrast, an appreciable re-entry can be demonstrated for diethyl-IDA. (orig.)

Renal radioisotope clearance in an unselected group of diabetics - a tool for the early recognition of diabetic nephropathy

International Nuclear Information System (INIS)

Doschek, D.; Wulf, R.; Krause, F.J.; Kreiskrankenhaus Albstadt

1980-01-01

Our study in unselected patients with diabetes was undertaken to determine the relation between glomerular filtration rate (GFR) and renal plasma flow (RPF) according to the patient's age. The diagnostic work-up was done with patients in unselected disease states because a classification of all systemic manifestations of the diabetes was not possible. The lack of selection may therefore reduce the value of our statistical results. From age 55 onwards, there was a reduction in GFR and, to a lesser extent, in PRF esceeding that which was age-dependent. It is, therefore, recommended to check the clearance in all patients with diabetes older than 55 years. The clearance with radioisotopically labeled substances, being a very sensitive method for the evaluation of restricted renal function, may permit an early recognition of diabetic nephropathy. (orig.) [de

48 CFR 2452.237-75 - Clearance of contractor personnel.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Clearance of contractor... Clauses 2452.237-75 Clearance of contractor personnel. As prescribed in 2437.110(e), insert the following clause in solicitations and contracts. Clearance of Contractor Personnel (OCT 1999) (a) General. This...

Plasma kinetics of sup 125 I beta endorphin turnover in lean and obese Zucker rats

Energy Technology Data Exchange (ETDEWEB)

Rodd, D.; Caston, A.L.; Green M.H.; Farrell, P.A. (Pennsylvania State Univ., University Park (United States))

1990-02-26

Plasma clearance kinetics for Beta Endorphin (BEP) are not well-defined and no definitive data exist for lean versus obese animals. To determine such kinetic parameters, a bolus of {sup 125}I BEP (1{mu}Ci/kg) was infused into awake lean(L) and obese(O) Zucker rats. Arterial blood samples were withdrawn initially at 20 seconds intervals and less frequently as a 3-hour experimental period progressed. Donor rat blood was infused (venous catheter) to replace withdrawn blood. At 180 minutes approximately 10% of the initial dose remained in the plasma. Clearance kinetics for {sup 125}I BEP were analyzed by compartmental analysis. A 3-component equation (i.e., 3 compartment model) provided the best fit for both L and O groups. Plasma transit times were very rapid; however, plasma fractional catabolic rate was low. Plasma mean residence time was similar for both groups (50 minutes) as was recycle time. These data suggest that BEP kinetics are similar in L and O rats, and that this peptide may undergo extensive recycling into and out of the plasma compartment. The identity of the other two compartments requires further investigation.

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

International Nuclear Information System (INIS)

Lindblad, H.G.; Berg, U.B.

1994-01-01

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

Propofol clearance and volume of distribution are increased in patients with major burns.

Science.gov (United States)

Han, Tae-Hyung; Greenblatt, David J; Martyn, J A Jeevendra

2009-07-01

Propofol pharmacokinetics were examined in 17 adults with major burns during the hyperdynamic convalescent phase. Eighteen nonburned surgical patients served as controls. After a 2-mg/kg intravenous dose of propofol, blood samples were collected at multiple time points. Noncompartmental methods were used to calculate the pharmacokinetic parameters. The following indices were higher in burns than controls: propofol clearance (64+/-17 vs 29+/-4 mL/kg/min, Pclearance of propofol in burned patients may imply that these patients require higher doses or infusion rates of propofol to attain a target plasma concentration or pharmacodynamic effect.

Security Clearance Tracking System

Data.gov (United States)

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

Centrifugal compressor tip clearance and impeller flow

Energy Technology Data Exchange (ETDEWEB)

Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari [Laboratory of Fluid Dynamics, LUT School of Energy Systems, Lappeenranta University of Technology, Lappeenranta (Finland); Engeda, Abraham [Turbomachinery Laboratory, Dept. of Mechanical Engineering, Michigan State University, East Lansing (United States)

2016-11-15

Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease.

Centrifugal compressor tip clearance and impeller flow

International Nuclear Information System (INIS)

Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari; Engeda, Abraham

2016-01-01

Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease

Hepatic drug clearance following traumatic injury.

Science.gov (United States)

Slaughter, R L; Hassett, J M

1985-11-01

Trauma is a complex disease state associated with physiologic changes that have the potential to alter hepatic drug clearance mechanisms. These responses include alterations in hepatic blood flow, reduction in hepatic microsomal activity, reduction in hepatic excretion processes, and changes in protein binding. Hepatic blood flow is influenced by sympathomimetic activity. Both animal and human studies demonstrate an initial reduction and subsequent increase in hepatic blood flow, which coincides with an observed increase and subsequent return to normal in serum catecholamine concentrations. Unfortunately, there are no human studies that address the importance these findings may have to the clearance processes of high intrinsic clearance compounds. Animal studies of trauma indicate that hepatic microsomal activity is depressed during the post-traumatic period. Reduction in the hepatic clearance of antipyrine, a model low intrinsic compound, has also been demonstrated in animal models of trauma. In addition to these effects, hepatic excretion of substances such as indocyanine green and bilirubin have been demonstrated to be impaired in both traumatized animals and humans. Finally, substantial increases in the serum concentration of the binding protein alpha 1-acid glycoprotein occur in trauma patients. This has been reported to be associated with subsequent decreases in the free fraction of lidocaine and quinidine. In addition to changing serum drug concentration/response relationships, the pharmacokinetic behavior of drugs bound to alpha 1-acid glycoprotein should also change. Preliminary observations in our laboratory in a dog model of surgically-induced trauma have shown a reduction in the total clearance of lidocaine and reduction in free lidocaine concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrospinal Fluid Clearance in Alzheimer Disease Measured with Dynamic PET.

Science.gov (United States)

de Leon, Mony J; Li, Yi; Okamura, Nobuyuki; Tsui, Wai H; Saint-Louis, Les A; Glodzik, Lidia; Osorio, Ricardo S; Fortea, Juan; Butler, Tracy; Pirraglia, Elizabeth; Fossati, Silvia; Kim, Hee-Jin; Carare, Roxana O; Nedergaard, Maiken; Benveniste, Helene; Rusinek, Henry

2017-09-01

Evidence supporting the hypothesis that reduced cerebrospinal fluid (CSF) clearance is involved in the pathophysiology of Alzheimer disease (AD) comes primarily from rodent models. However, unlike rodents, in which predominant extracranial CSF egress is via olfactory nerves traversing the cribriform plate, human CSF clearance pathways are not well characterized. Dynamic PET with 18 F-THK5117, a tracer for tau pathology, was used to estimate the ventricular CSF time-activity as a biomarker for CSF clearance. We tested 3 hypotheses: extracranial CSF is detected at the superior turbinates; CSF clearance is reduced in AD; and CSF clearance is inversely associated with amyloid deposition. Methods: Fifteen subjects, 8 with AD and 7 normal control volunteers, were examined with 18 F-THK5117. Ten subjects additionally underwent 11 C-Pittsburgh compound B ( 11 C-PiB) PET scanning, and 8 were 11 C-PiB-positive. Ventricular time-activity curves of 18 F-THK5117 were used to identify highly correlated time-activity curves from extracranial voxels. Results: For all subjects, the greatest density of CSF-positive extracranial voxels was in the nasal turbinates. Tracer concentration analyses validated the superior nasal turbinate CSF signal intensity. AD patients showed ventricular tracer clearance reduced by 23% and 66% fewer superior turbinate CSF egress sites. Ventricular CSF clearance was inversely associated with amyloid deposition. Conclusion: The human nasal turbinate is part of the CSF clearance system. Lateral ventricle and superior nasal turbinate CSF clearance abnormalities are found in AD. Ventricular CSF clearance reductions are associated with increased brain amyloid depositions. These data suggest that PET-measured CSF clearance is a biomarker of potential interest in AD and other neurodegenerative diseases. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Analysis of conservativity analysis for clearance levels. Final report

International Nuclear Information System (INIS)

Deckert, A.; Thierfeldt, S.

1997-07-01

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

Numerical investigation of hub clearance flow in a Kaplan turbine

Science.gov (United States)

Wu, H.; Feng, J. J.; Wu, G. K.; Luo, X. Q.

2012-11-01

In this paper, the flow field considering the hub clearance flow in a Kaplan turbine has been investigated through using the commercial CFD code ANSYS CFX based on high-quality structured grids generated by ANSYS ICEM CFD. The turbulence is simulated by k-ω based shear stress transport (SST) turbulence model together with automatic near wall treatments. Four kinds of simulations have been conducted for the runner geometry without hub clearance, with only the hub front clearance, with only the rear hub clearance, and with both front and rear clearance. The analysis of the obtained results is focused on the flow structure of the hub clearance flow, the effect on the turbine performance including hydraulic efficiency and cavitation performance, which can improve the understanding on the flow field in a Kaplan turbine.

Numerical investigation of hub clearance flow in a Kaplan turbine

International Nuclear Information System (INIS)

Wu, H; Feng, J J; Wu, G K; Luo, X Q

2012-01-01

In this paper, the flow field considering the hub clearance flow in a Kaplan turbine has been investigated through using the commercial CFD code ANSYS CFX based on high-quality structured grids generated by ANSYS ICEM CFD. The turbulence is simulated by k-ω based shear stress transport (SST) turbulence model together with automatic near wall treatments. Four kinds of simulations have been conducted for the runner geometry without hub clearance, with only the hub front clearance, with only the rear hub clearance, and with both front and rear clearance. The analysis of the obtained results is focused on the flow structure of the hub clearance flow, the effect on the turbine performance including hydraulic efficiency and cavitation performance, which can improve the understanding on the flow field in a Kaplan turbine.

Kinetic parameters for plasma β-endorphin in lean and obese Zucker rats

International Nuclear Information System (INIS)

Rodd, D.; Farrell, P.A.; Caston, A.L.; Green, M.H.

1991-01-01

To determine plasma clearance kinetics for β-endorphin (BE) by empirical compartmental analysis, a bolus of radioactive labeled 125I-BE was rapidly injected into a carotid artery catheter of unanesthetized lean (L) and obese (O) Zucker rats. The plasma disappearance of 125I was followed over a 3-h period. A 3-component exponential equation provided the best fit for plasma data. Plasma transit times were very short (10 s); however, plasma fractional catabolic rate was much slower. Plasma mean residence time was similar for both groups (50 min) as was recycle time (1.3 min). These data suggest that BE plasma disappearance kinetics are similar in L and O rats

Kinetic parameters for plasma. beta. -endorphin in lean and obese Zucker rats

Energy Technology Data Exchange (ETDEWEB)

Rodd, D.; Farrell, P.A.; Caston, A.L.; Green, M.H. (Department of Exercise and Sport Science, Pennsylvania State University, University Park (USA))

1991-03-01

To determine plasma clearance kinetics for {beta}-endorphin (BE) by empirical compartmental analysis, a bolus of radioactive labeled 125I-BE was rapidly injected into a carotid artery catheter of unanesthetized lean (L) and obese (O) Zucker rats. The plasma disappearance of 125I was followed over a 3-h period. A 3-component exponential equation provided the best fit for plasma data. Plasma transit times were very short (10 s); however, plasma fractional catabolic rate was much slower. Plasma mean residence time was similar for both groups (50 min) as was recycle time (1.3 min). These data suggest that BE plasma disappearance kinetics are similar in L and O rats.

Airway Clearance Techniques (ACTs)

Medline Plus

Full Text Available ... Research Consortia CF Biomarker Consortium CFTR 3-D Structure Consortium CFTR Folding Consortium Epithelial Stem Cell Consortium Mucociliary Clearance Consortium SUCCESS WITH THERAPIES RESEARCH ...

Inherited Disorders of Bilirubin Clearance

Science.gov (United States)

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

Approaches towards establishing of clearance levels in Japan

International Nuclear Information System (INIS)

Sumitani, N.; Watanabe, I.; Okoshi, M.

1998-01-01

It is important to establish necessary regulatory systems for decommissioning waste management, especially to establish clearance levels from regulatory control. To establish the regulatory systems, the Nuclear Safety Commission (NSC) has been discussing the unconditional clearance levels for materials from nuclear reactors since May 1997. The NSC tries to derive unconditional clearance levels for the materials such as concrete and ferrous metal, arising from nuclear reactor decommissioning. In the derivation, both disposal and recycle/reuse of the materials are considered. Typical scenarios and parameter values for dose estimation are selected considering the Japanese natural and social conditions. Preliminary clearance levels were derived from 10 μSv/yr of individual dose criterion and deterministic analysis. For most radionuclides, the preliminary results are the same order of magnitude recommended in IAEA-TECDOC-855. Some radionuclides such as β emitters, however, are different order of magnitude from those recommended in IAEA-TECDOC-855. It is necessary that international organizations lead the discussions on the clearance levels to conclude final consensus. (author)

Green technology; only Forest Clearance is needed

Indian Academy of Sciences (India)

First page Back Continue Last page Graphics. How was Forest Clearance granted before the procedures for constitution of ESZ was completed? How was Forest Clearance granted before the procedures for constitution of ESZ was completed? How was land in Murmurwadi still under litigation made available? How was ...

Nuclear regulation. NRC's security clearance program can be strengthened

International Nuclear Information System (INIS)

Fultz, Keith O.; Kruslicky, Mary Ann; Bagnulo, John E.

1988-12-01

Because of the national security implications of its programs, the Nuclear Regulatory Commission (NRC) investigates the background of its employees and consultants as well as others to ensure that they are reliable and trustworthy. If the investigation indicates that an employee will not endanger national security, NRC grants a security clearance that allows access to classified information, material, and facilities. NRC also requires periodic checks for some clearance holders to ensure their continued clearance eligibility. The Chairman, Subcommittee on Environment, Energy, and Natural Resources, House Committee on Government Operations, asked GAO to review NRC's personnel security clearance program and assess the procedures that NRC uses to ensure that those who operate nuclear power plants do not pose a threat to the public. The Atomic Energy Act of 1954 requires NRC to conduct background investigations of its employees and consultants as well as others who have access to classified information, material, or facilities. To do this, NRC established a personnel security clearance program. Under NRC policies, a security clearance is granted after the Office of Personnel Management (OPM) or the Federal Bureau of Investigation checks the background of those applying for an NRC clearance. NRC also periodically reassesses the integrity of those holding the highest level clearance. NRC employees, consultants, contractors, and licensees as well as other federal employees hold approximately 10,600 NRC clearances. NRC does not grant clearances to commercial nuclear utility employees unless they require access to classified information or special nuclear material. However, the utilities have voluntarily established screening programs to ensure that their employees do not pose a threat to nuclear plants. NRC faces a dilemma when it hires new employees. Although its policy calls for new hires to be cleared before they start work, the security clearance process takes so long

Airway Clearance Techniques (ACTs)

Medline Plus

Full Text Available ... Cell Consortium Mucociliary Clearance Consortium SUCCESS WITH THERAPIES RESEARCH CONSORTIUM Therapeutics Development Network TDN Coordinating Center Study Services Working With the TDN Tools and Resources ...

Airway Clearance Techniques (ACTs)

Medline Plus

Full Text Available ... 3-D Structure Consortium CFTR Folding Consortium Epithelial Stem Cell Consortium Mucociliary Clearance Consortium SUCCESS WITH THERAPIES RESEARCH CONSORTIUM Therapeutics Development Network TDN Coordinating Center ...

A study for promoting measures of social acceptance on clearance system

International Nuclear Information System (INIS)

Okoshi, Minoru; Torii, Hiroyuki; Fujii, Yasuhiko

2007-01-01

Clearance is one of the useful concepts to manage large amounts of slightly contaminated solid radioactive materials generated from the decommissioning of nuclear facilities. Cleared materials are expected to be disposed of as conventional wastes or recycled to produce consumer goods. In Japan, the legal frame-work for clearance was established in 2005 by amending the Law to regulate nuclear materials, reactors and so on. However, it is not so clear whether the general public understands clearance well. In this paper, major concerns about clearance from the general public are analyzed based on the public comments for reports on clearance prepared by the Nuclear Safety Commission and the Nuclear Institute Safety Agency. The major anxieties for clearance expressed by the general public are the safety of clearance, unknown factors of radiation effects, possibilities of excess radiation exposure due to inadequate measurements of radioactivities and fairness in decision making. In order to deal with those anxieties, some countermeasures including the confidence in nuclear operators and regulatory authorities and controllability of clearance by the general public are discussed to promote the social acceptance of clearance by the general public. (author)

Airway Clearance Techniques (ACTs)

Medline Plus

Full Text Available ... 3-D Structure Consortium CFTR Folding Consortium Epithelial Stem Cell Consortium Mucociliary Clearance Consortium SUCCESS WITH THERAPIES RESEARCH CONSORTIUM Therapeutics Development Network TDN Coordinating Center Study ...

Frequency and causes of discrepancy between Kt/V and creatinine clearance.

Science.gov (United States)

Satko, S G; Burkart, J M; Bleyer, A J; Jordan, J R; Manning, T

1999-01-01

This study examines the frequency of discrepancy between Kt/V urea and creatinine clearance (Ccr) measurements in patients on peritoneal dialysis (PD) and the reasons for this discrepancy. Nonrandomized, retrospective data analysis. Single PD unit of a university teaching hospital. All adult patients receiving PD at our center from January 1995 to December 1996. Actual (a) and desired (d) body weight (BW) were used to calculate urea volume of distribution (V) and body surface area (BSA). Patients were divided into four groups based upon their total small solute clearances (Kt/V and Ccr, normalized by actual weight) and three additional groups based upon actual/desired (a/d) body weight ratio. An additional analysis was performed for the subset of anuric patients. Data collected for all patients included the following: total Kt, total Ccr, 4-hour dialysate/ plasma (D/P) creatinine, serum albumin concentration, duration of PD, actual body weight, age, and height. Twenty-three percent of the clearance measurements in our study were discrepant, defined as having values for either Kt/V or Ccr (but not both) above the accepted targets of Kt/V > or = 2.0/wk and Ccr > or = 60 L/wk/ 1.73 m2. Patients with both values above target are more likely to have higher residual renal function. Patients who are significantly less than BWd and patients on PD for a longer time are more likely to have adequate Kt/V but not Ccr. Furthermore, patients who are less than 90% or greater than 110% of BWd have markedly different values for Kt/V and Ccr when BWa versus BWd values are used. Kt/V and Ccr values are frequently discrepant; a number of factors affect these two measurements to varying degrees, including weight, degree of residual renal function, and duration of PD.

Intraarticular volume and clearance in human synovial effusions

International Nuclear Information System (INIS)

Wallis, W.J.; Simkin, P.A.; Nelp, W.B.; Foster, D.M.

1985-01-01

Intraarticular volumes were measured by radiolabeled albumin (RISA) distribution in chronic knee effusions from 11 rheumatoid arthritis patients and 9 osteoarthritis patients. Volumes of synovial fluid obtained at joint aspiration were substantially less than those found by RISA dilution. Up to 24 hours was needed for full distribution of RISA throughout the intraarticular compartment. Measured 123I and RISA radioactivity over the knee described monoexponential rate constants, lambda (minute-1). The clearance of 123I and RISA from synovial effusions was derived by the formulation volume (ml) X lambda (minute-1) = clearance (ml/minute). RISA clearance in rheumatoid effusions was significantly greater than that found in osteoarthritis effusions. Intraarticular volume and isotope clearance were easily quantified and provide measures for further evaluating the microvascular physiology of synovial effusions

In nondiabetic, human immunodeficiency virus-infected patients with lipodystrophy, hepatic insulin extraction and posthepatic insulin clearance rate are decreased in proportion to insulin resistance

DEFF Research Database (Denmark)

Haugaard, Steen B; Andersen, Ove; Hansen, Birgitte R

2005-01-01

In healthy, nondiabetic individuals with insulin resistance, fasting insulin is inversely correlated to the posthepatic insulin clearance rate (MCRi) and the hepatic insulin extraction (HEXi). We investigated whether similar early mechanisms to facilitate glucose homeostasis exist in nondiabetic...... > .1). Our data suggest that HEXi and MCRi are decreased in proportion to the degree of insulin resistance in nondiabetic HIV-infected patients with lipodystrophy....... insulin clearance rate was estimated as the ratio of posthepatic insulin appearance rate to steady-state plasma insulin concentration during a euglycemic hyperinsulinemic clamp (40 mU.m-2 .min-1). Posthepatic insulin appearance rate during the clamp was calculated, taking into account the remnant...

Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts

Science.gov (United States)

Lattime, Scott B.; Steinetz, Bruce M.; Robbie, Malcolm G.

2003-01-01

Improved blade tip sealing in the high pressure compressor and high pressure turbine can provide dramatic improvements in specific fuel consumption, time-on-wing, compressor stall margin and engine efficiency as well as increased payload and mission range capabilities of both military and commercial gas turbine engines. The preliminary design of a mechanically actuated active clearance control (ACC) system for turbine blade tip clearance management is presented along with the design of a bench top test rig in which the system is to be evaluated. The ACC system utilizes mechanically actuated seal carrier segments and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. The purpose of this active clearance control system is to improve upon current case cooling methods. These systems have relatively slow response and do not use clearance measurement, thereby forcing cold build clearances to set the minimum clearances at extreme operating conditions (e.g., takeoff, re-burst) and not allowing cruise clearances to be minimized due to the possibility of throttle transients (e.g., step change in altitude). The active turbine blade tip clearance control system design presented herein will be evaluated to ensure that proper response and positional accuracy is achievable under simulated high-pressure turbine conditions. The test rig will simulate proper seal carrier pressure and temperature loading as well as the magnitudes and rates of blade tip clearance changes of an actual gas turbine engine. The results of these evaluations will be presented in future works.

R-warfarin clearances from plasma associated with polymorphic cytochrome P450 2C19 and simulated by individual physiologically based pharmacokinetic models for 11 cynomolgus monkeys.

Science.gov (United States)

Utoh, Masahiro; Kusama, Takashi; Miura, Tomonori; Mitsui, Marina; Kawano, Mirai; Hirano, Takahiro; Shimizu, Makiko; Uno, Yasuhiro; Yamazaki, Hiroshi

2018-02-01

1. Cynomolgus monkey cytochrome P450 2C19 (formerly known as P450 2C75), homologous to human P450 2C19, has been identified as R-warfarin 7-hydroxylase. In this study, simulations of R-warfarin clearance in individual cynomolgus monkeys genotyped for P450 2C19 p.[(Phe100Asn; Ala103Val; Ile112Leu)] were performed using individual simplified physiologically based pharmacokinetic (PBPK) modeling. 2. Pharmacokinetic parameters and absorption rate constants, volumes of the systemic circulation, and hepatic intrinsic clearances for individual PBPK models were estimated for eleven cynomolgus monkeys. 3. One-way ANOVA revealed significant effects of the genotype (p warfarin among the homozygous mutant, heterozygous mutant, and wild-type groups. R-Warfarin clearances in individual cynomolgus monkeys genotyped for P450 2C19 were simulated by simplified PBPK modeling. The modeled hepatic intrinsic clearances were significantly associated with the P450 2C19 genotypes. The liver microsomal elimination rates of R-warfarin for individual animals after in vivo administration showed significant reductions associated with the genotype (p warfarin and related medicines associated with polymorphic P450 2C19 in individual cynomolgus monkeys, thereby facilitating calculation of the fraction of hepatic clearance.

The tear turnover and tear clearance tests - a review.

Science.gov (United States)

Garaszczuk, Izabela K; Montes Mico, Robert; Iskander, D Robert; Expósito, Alejandro Cerviño

2018-03-01

The aim is to provide a summary of methods available for the assessment of tear turnover and tear clearance rates. The review defines tear clearance and tear turnover and describes their implication for ocular surface health. Additionally, it describes main types of techniques for measuring tear turnover, including fluorescein tear clearance tests, techniques utilizing electromagnetic spectrum and tracer molecule and novel experimental techniques utilizing optical coherence tomography and fluorescein profilometry. Areas covered: Internet databases (PubMed, Science Direct, Google Scholar) and most frequently cited references were used as a principal resource of information on tear turnover rate and tear clearance rate, presenting methodologies and equipment, as well as their definition and implications for the anterior eye surface health and function. Keywords used for data-search were as follows: tear turnover, tear clearance, fluorescein clearance, scintigraphy, fluorophotometry, tear flow, drainage, tear meniscus dynamics, Krehbiel flow and lacrimal functional unit. Expert commentary: After decades, the topic of tear turnover assessment has been reintroduced. Recently, new techniques have been developed to propose less invasive, less time consuming and simpler methodologies for the assessment of tear dynamics that have the potential to be utilized in clinical practice.

Airway Clearance Techniques (ACTs)

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Full Text Available ... Community in Health Care Reform Milestones in Health Care Reform How Tax Reform Could Impact People With CF The ... Home Life With CF Treatments and Therapies Airway Clearance ...

Oral fluid and plasma 3,4-methylenedioxymethamphetamine (MDMA) and metabolite correlation after controlled oral MDMA administration.

Science.gov (United States)

Desrosiers, Nathalie A; Barnes, Allan J; Hartman, Rebecca L; Scheidweiler, Karl B; Kolbrich-Spargo, Erin A; Gorelick, David A; Goodwin, Robert S; Huestis, Marilyn A

2013-05-01

Oral fluid (OF) offers a noninvasive sample collection for drug testing. However, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) in OF has not been adequately characterized in comparison to plasma. We administered oral low-dose (1.0 mg/kg) and high-dose (1.6 mg/kg) MDMA to 26 participants and collected simultaneous OF and plasma specimens for up to 143 h after dosing. We compared OF/plasma (OF/P) ratios, time of initial detection (t first), maximal concentrations (C max), time of peak concentrations (t max), time of last detection (t last), clearance, and 3,4-methylenedioxyamphetamine (MDA)-to-MDMA ratios over time. For OF MDMA and MDA, C max was higher, t last was later, and clearance was slower compared to plasma. For OF MDA only, t first was later compared to plasma. Median (range) OF/P ratios were 5.6 (0.1-52.3) for MDMA and 3.7 (0.7-24.3) for MDA. OF and plasma concentrations were weakly but significantly correlated (MDMA: R(2) = 0.438, MDA: R(2) = 0.197, p MDMA low = 5.2 (0.1-40.4), high = 6.0 (0.4-52.3, p MDMA ratios in plasma were higher than those in OF (p MDMA ratios significantly increased over time in OF and plasma. The MDMA and MDA concentrations were higher in OF than in plasma. OF and plasma concentrations were correlated, but large inter-subject variability precludes the estimation of plasma concentrations from OF.

Effect of clearance on cartilage tribology in hip hemi-arthroplasty.

Science.gov (United States)

Lizhang, Jia; Taylor, Simon D; Jin, Zhongmin; Fisher, John; Williams, Sophie

2013-12-01

Hemi-arthroplasty of the hip (an artificial femoral head articulating against the natural acetabulum) is used to treat fractured necks of femur; however, there is evidence that articulation causes erosion of the cartilage, resulting in pain for the patient. Parameters that may influence this cartilage erosion include head material and roughness, clearance between the head and acetabulum and activity levels of the patient. This study has assessed the effect of clearance of hemi-arthroplasty articulations on the contact stress, friction and cartilage deformation in an in vitro tribological simulation of the hemi-arthroplasty joint that applied dynamic loads and motion. It has been demonstrated that peak contact stress increased from 5.6 to 10.6 MPa as radial clearance increased from small (1.8 mm). In all samples, friction factor increased with time and was significantly less with extra-large clearances compared to small (<0.6 mm), medium (0.6-1.2 mm) and large (1.2-1.8 mm) clearances. The cartilage deformation observed was significantly greater in acetabulum samples paired to give small or extra-large clearances compared to those with medium or large clearances.

The signal peptide anchors apolipoprotein M in plasma lipoproteins and prevents rapid clearance of apolipoprotein M from plasma

DEFF Research Database (Denmark)

Christoffersen, Christina; Ahnström, Josefin; Axler, Olof

2008-01-01

Lipoproteins consist of lipids solubilized by apolipoproteins. The lipid-binding structural motifs of apolipoproteins include amphipathic alpha-helixes and beta-sheets. Plasma apolipoprotein (apo) M lacks an external amphipathic motif but, nevertheless, is exclusively associated with lipoproteins...... (mainly high density lipoprotein). Uniquely, however, apoM is secreted to plasma without cleavage of its hydrophobic NH(2)-terminal signal peptide. To test whether the signal peptide serves as a lipoprotein anchor for apoM in plasma, we generated mice expressing a mutated apoM(Q22A) cDNA in the liver (apoM......(Q22A)-Tg mice (transgenic mice)) and compared them with mice expressing wild-type human apoM (apoM-Tg mice). The substitution of the amino acid glutamine 22 with alanine in apoM(Q22A) results in secretion of human apoM without a signal peptide. The human apoM mRNA level in liver and the amount...

Serum Creatinine Versus Plasma Methotrexate Levels to Predict Toxicities in Children Receiving High-dose Methotrexate.

Science.gov (United States)

Tiwari, Priya; Thomas, M K; Pathania, Subha; Dhawan, Deepa; Gupta, Y K; Vishnubhatla, Sreenivas; Bakhshi, Sameer

2015-01-01

Facilities for measuring methotrexate (MTX) levels are not available everywhere, potentially limiting administration of high-dose methotrexate (HDMTX). We hypothesized that serum creatinine alteration after HDMTX administration predicts MTX clearance. Overall, 122 cycles in 50 patients of non-Hodgkin lymphoma or acute lymphoblastic leukemia aged ≤18 years receiving HDMTX were enrolled prospectively. Plasma MTX levels were measured at 12, 24, 36, 48, 60, and 72 hours; serum creatinine was measured at baseline, 24, 48, and 72 hours. Correlation of plasma MTX levels with creatinine levels and changes in creatinine from baseline (Δ creatinine) were evaluated. Plasma MTX levels at 72 hours showed positive correlation with serum creatinine at 48 hours (P = .011) and 72 hours (P = .013) as also Δ creatinine at 48 hours (P = .042) and 72 hours (P = .045). However, cut-off value of either creatinine or Δ creatinine could not be established to reliably predict delayed MTX clearance. Greater than 50% Δ creatinine at 48 and 72 hours significantly predicted grade 3/4 leucopenia (P = .036 and P = .001, respectively) and thrombocytopenia (P = .012 and P = .009, respectively) but not mucositis (P = .827 and P = .910, respectively). Delayed MTX elimination did not predict any grade 3/4 toxicity. In spite of demonstration of significant correlation between serum creatinine and Δ creatinine with plasma MTX levels at 72 hours, cut-off value of either variable to predict MTX delay could not be established. Thus, either of these cannot be used as a surrogate for plasma MTX estimation. Interestingly, Δ creatinine effectively predicted hematological toxicities, which were not predicted by delayed MTX clearance.

A High Throughput, 384-Well, Semi-Automated, Hepatocyte Intrinsic Clearance Assay for Screening New Molecular Entities in Drug Discovery.

Science.gov (United States)

Heinle, Lance; Peterkin, Vincent; de Morais, Sonia M; Jenkins, Gary J; Badagnani, Ilaria

2015-01-01

A high throughput, semi-automated clearance screening assay in hepatocytes was developed allowing a scientist to generate data for 96 compounds in one week. The 384-well format assay utilizes a Thermo Multidrop Combi and an optimized LC-MS/MS method. The previously reported LCMS/ MS method reduced the analytical run time by 3-fold, down to 1.2 min injection-to-injection. The Multidrop was able to deliver hepatocytes to 384-well plates with minimal viability loss. Comparison of results from the new 384-well and historical 24-well assays yielded a correlation of 0.95. In addition, results obtained for 25 marketed drugs with various metabolism pathways had a correlation of 0.75 when compared with literature values. Precision was maintained in the new format as 8 compounds tested in ≥39 independent experiments had coefficients of variation ≤21%. The ability to predict in vivo clearances using the new stability assay format was also investigated using 22 marketed drugs and 26 AbbVie compounds. Correction of intrinsic clearance values with binding to hepatocytes (in vitro data) and plasma (in vivo data) resulted in a higher in vitro to in vivo correlation when comparing 22 marketed compounds in human (0.80 vs 0.35) and 26 AbbVie Discovery compounds in rat (0.56 vs 0.17), demonstrating the importance of correcting for binding in clearance studies. This newly developed high throughput, semi-automated clearance assay allows for rapid screening of Discovery compounds to enable Structure Activity Relationship (SAR) analysis based on high quality hepatocyte stability data in sufficient quantity and quality to drive the next round of compound synthesis.

Modified Augmented Renal Clearance Score Predicts Rapid Piperacillin and Tazobactam Clearance in Critically Ill Surgery and Trauma Patients

Science.gov (United States)

2014-04-24

collision; VAP , ventilator-associated pneumonia. TABLE 2. PK Parameter Estimates for Free Piperacillin and Tazobactam in Patients Stratified by ARC Score...SOFA score are typically generated during routine care of the most severely ill patients . Positive screening test results (high ARC scores) can be...Modified Augmented Renal Clearance score predicts rapid piperacillin and tazobactam clearance in critically ill surgery and trauma patients Kevin S

Dopamine plasma clearance is increased in piglets compared to neonates during continuous dopamine infusion

DEFF Research Database (Denmark)

Rasmussen, Martin B; Gramsbergen, Jan Bert; Eriksen, Vibeke Ramsgaard

2018-01-01

pharmacokinetics. METHODS: Arterial blood samples were drawn from six neonates admitted to the neonatal intensive care unit of Copenhagen University Hospital and 20 newborn piglets during continuous dopamine infusion. Furthermore, to estimate the piglet plasma dopamine half-life, blood samples were drawn at 2.......5-minute intervals after the dopamine infusion was discontinued. The plasma dopamine content was analysed by high-performance liquid chromatography with electrochemical detection. RESULTS: The dopamine displayed first-order kinetics in piglets and had a half-life of 2.5 minutes, while the median plasma...

Plasma and cerebrospinal fluid pharmacokinetics of flurbiprofen in children

Science.gov (United States)

Kumpulainen, Elina; Välitalo, Pyry; Kokki, Merja; Lehtonen, Marko; Hooker, Andrew; Ranta, Veli-Pekka; Kokki, Hannu

2010-01-01

AIMS This study was designed to characterize paediatric pharmacokinetics and central nervous system exposure of flurbiprofen. METHODS The pharmacokinetics of flurbiprofen were studied in 64 healthy children aged 3 months to 13 years, undergoing surgery with spinal anaesthesia. Children were administered preoperatively a single dose of flurbiprofen intravenously as prodrug (n = 27) or by mouth as syrup (n = 37). A single cerebrospinal fluid (CSF) sample (n = 60) was collected at the induction of anaesthesia, and plasma samples (n = 304) before, during and after the operation (up to 20 h after administration). A population pharmacokinetic model was built using the NONMEM software package. RESULTS Flurbiprofen concentrations in plasma were well described by a three compartment model. The apparent bioavailability of oral flurbiprofen syrup was 81%. The estimated clearance (CL) was 0.96 l h−1 70 kg−1. Age did not affect the clearance after weight had been included as a covariate. The estimated volume of distribution at steady state (Vss) was 8.1 l 70 kg−1. Flurbiprofen permeated into the CSF, reaching concentrations that were seven-fold higher compared with unbound plasma concentrations. CONCLUSIONS Flurbiprofen pharmacokinetics can be described using only weight as a covariate in children above 6 months, while more research is needed in neonates and in younger infants. PMID:20840447

Airway Clearance Techniques (ACTs)

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Full Text Available ... in CF Clinical Care Guidelines Cystic Fibrosis-Related Diabetes Clinical Care Guidelines Liver Disease Clinical Care Guidelines Respiratory Care Guidelines CF Airway Clearance Therapies Clinical Care Guidelines Chronic Medications to Maintain Lung ...

Correlation between Creatinine Clearance and Transtubular Potassium Concentration Gradient in old people and chronic renal disease patients

International Nuclear Information System (INIS)

Musso, C.; Imperiali, N.; Algranati, L.; Miguel, R.D.; Liakopoulos, V.; Stefanidis, I.

2007-01-01

Senescence and chronic kidney disease (CKD) reduce progressively glomerular filtration rate (GFR) which usually results in an increase in potassium renal secretion. To evaluate whether the transtubular potassium concentration gradient (TTKG) is more accurate parameter for evaluating the renal secretion of this cation than using fractional excretion of potassium as its urinary secretion marker, we studied 55 subjects, 43 of them were healthy elderly volunteers and 12 were CKD patients. Exclusion criteria were: abnormal plasma potassium level or presence of any disease or drug that could induce alteration of balance of this electrolyte levels. All the subjects were on a diet with potassium content around 50 mmol/day. The curves, which demonstrate the relationship between creatinine clearance and TTKG and the grade of correlation between these two parameters were analyzed in both groups. We found that the transtubular potassium concentration gradient had a significant negative correlation with the creatinine clearance level in the healthy elderly group, while there was no correlation in the CKD group. (author)

2015 Annual Report on Security Clearance Determinations

Science.gov (United States)

2016-06-28

only have delegated investigative authority over their civilian employee population and therefore, can only report the overall timeliness for that...completed or pending security clearance determinations for government employees and contractors during the preceding fiscal year that have taken longer...Clearance Determinations to Congress. The IAA directs this report to include the number of United States Government (USG) employees who held a

Dynamic modelling and experimental study of cantilever beam with clearance

International Nuclear Information System (INIS)

Li, B; Jin, W; Han, L; He, Z

2012-01-01

Clearances occur in almost all mechanical systems, typically such as the clearance between slide plate of gun barrel and guide. Therefore, to study the clearances of mechanisms can be very important to increase the working performance and lifetime of mechanisms. In this paper, rigid dynamic modelling of cantilever with clearance was done according to the subject investigated. In the rigid dynamic modelling, clearance is equivalent to the spring-dashpot model, the impact of beam and boundary face was also taken into consideration. In ADAMS software, the dynamic simulation was carried out according to the model above. The software simulated the movement of cantilever with clearance under external excitation. Research found: When the clearance is larger, the force of impact will become larger. In order to study how the stiffness of the cantilever's supporting part influences natural frequency of the system, A Euler beam which is restricted by a draught spring and a torsion spring at its end was raised. Through numerical calculation, the relationship between natural frequency and stiffness was found. When the value of the stiffness is close to the limit value, the corresponding boundary condition is illustrated. An ADAMS experiment was carried out to check the theory and the simulation.

Dynamic modelling and experimental study of cantilever beam with clearance

Science.gov (United States)

Li, B.; Jin, W.; Han, L.; He, Z.

2012-05-01

Clearances occur in almost all mechanical systems, typically such as the clearance between slide plate of gun barrel and guide. Therefore, to study the clearances of mechanisms can be very important to increase the working performance and lifetime of mechanisms. In this paper, rigid dynamic modelling of cantilever with clearance was done according to the subject investigated. In the rigid dynamic modelling, clearance is equivalent to the spring-dashpot model, the impact of beam and boundary face was also taken into consideration. In ADAMS software, the dynamic simulation was carried out according to the model above. The software simulated the movement of cantilever with clearance under external excitation. Research found: When the clearance is larger, the force of impact will become larger. In order to study how the stiffness of the cantilever's supporting part influences natural frequency of the system, A Euler beam which is restricted by a draught spring and a torsion spring at its end was raised. Through numerical calculation, the relationship between natural frequency and stiffness was found. When the value of the stiffness is close to the limit value, the corresponding boundary condition is illustrated. An ADAMS experiment was carried out to check the theory and the simulation.

Airway Clearance Techniques (ACTs)

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Full Text Available ... many challenges, including medical, social, and financial. By learning more about how you can manage your disease every day, you can ultimately help find a ... Cycle of Breathing Technique Airway Clearance Techniques Autogenic ...

Refrigeration system with clearance seals

International Nuclear Information System (INIS)

Holland, N. J.

1985-01-01

In a refrigeration system such as a split Stirling system, fluid seals associated with the reciprocating displacer are virtually dragless clearance seals. Movement of the displacer relative to the pressure variations in the working volume of gas is retarded by a discrete braking element. Because it is not necessary that the brake providing any sealing action, the brake can be designed for greater durability and less dependence on ambient and operating temperatures. Similarly, the clearance seal can be formed of elements having low thermal expansion such that the seal is not temperature dependent. In the primary embodiments the braking element is a split friction brake

Chaos vibration of pinion and rack steering trapezoidal mechanism containing two clearances

Science.gov (United States)

Wei, Daogao; Wang, Yu; Jiang, Tong; Zheng, Sifa; Zhao, Wenjing; Pan, Zhijie

2017-08-01

The multi-clearances of breaking type steering trapezoidal mechanism joints influences vehicle steering stability. Hence, to ascertain the influence of clearance value on steering stability, this paper takes the steering mechanism of a certain vehicle type as a prototype that can be simplified into a planar six-bar linkage, then establishes the system dynamic differential equations after considering the two clearances of tie rods and the steering knuckle arms. The influence of the clearance parameters on the movement stability of the steering mechanism is studied using a numerical computation method. Results show that when the two clearances are equal, the planar movement of the tie rods changes from period-doubling to chaos as the clearances increase. When the two clearances are 0.25 mm and 1.5 mm respectively, the planar movements of the two side tie rods come into chaos, causing the steering stability to deteriorate. Moreover, with the increase of clearances, turning moment fluctuates more intensively and the peak value increases.

Airway Clearance Techniques (ACTs)

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Full Text Available ... decisions about your health care. CF Genetics: The Basics CF Mutations Video Series Find Out More About ... of Breathing Technique Airway Clearance Techniques Autogenic Drainage Basics of Lung Care Chest Physical Therapy Coughing and ...

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Full Text Available ... Clinician Career Development Awards Clinician Training Awards Mutation Analysis Program Network News Network News: March 2018 Network ... for airway clearance. Facebook Twitter Email More Related Content Medications Autogenic Drainage Positive Expiratory Pressure High-Frequency ...

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Full Text Available ... today. ANNUAL FUND Become a Corporate Supporter Cause Marketing Make a Charitable Gift Our Corporate Supporters Workplace ... for airway clearance. Facebook Twitter Email More Related Content Medications Autogenic Drainage Positive Expiratory Pressure High-Frequency ...

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Full Text Available ... specialized CF care and a range of treatment options. Airway Clearance Active Cycle of Breathing Technique Airway ... on their own. Share Facebook Twitter Email More options Print Share Facebook Twitter Email Print Permalink All ...

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Full Text Available ... Clinician Career Development Awards Clinician Training Awards Mutation Analysis Program Network News Network News: June 2018 Network ... for airway clearance. Facebook Twitter Email More Related Content Medications Autogenic Drainage Positive Expiratory Pressure High-Frequency ...

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Full Text Available ... a Family Parenting as an Adult With CF Treatments and Therapies People with cystic fibrosis are living ... to specialized CF care and a range of treatment options. Airway Clearance Active Cycle of Breathing Technique ...

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Full Text Available ... Physical Therapy Coughing and Huffing High-Frequency Chest Wall Oscillation Positive Expiratory Pressure Clinical Trials Clinical Trials ... clapping) or vibration to loosen mucus from airway walls. See how different airway clearance techniques work to ...

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Full Text Available ... in part to specialized CF care and a range of treatment options. Airway Clearance Active Cycle of ... a cure for CF and supports a broad range of research initiatives to tackle the disease from ...

Airway Clearance Techniques (ACTs)

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Full Text Available ... ACTs involve coughing or huffing . Many of them use percussion (clapping) or vibration to loosen mucus from airway walls. See how different airway clearance techniques work to help you clear the thick, sticky mucus ...

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Full Text Available ... Clinical Care Guidelines Liver Disease Clinical Care Guidelines Respiratory Care Guidelines CF Airway Clearance Therapies Clinical Care ... attack bacteria. Choose What's Best for You Your respiratory therapist or another member of your CF care ...

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Full Text Available ... Cycle of Breathing Technique Airway Clearance Techniques Autogenic Drainage Basics of Lung Care Chest Physical Therapy Coughing ... Facebook Twitter Email More Related Content Medications Autogenic Drainage Positive Expiratory Pressure High-Frequency Chest Wall Oscillation ( ...

Two-dimensional analysis of limiter/divertor transition in scrape-off layer plasmas

International Nuclear Information System (INIS)

Ueda, N.; Itoh, K.; Itoh, S.I.

1989-01-01

The structures of scrape-off layer and divertor plasmas have been studied numerically with a neutral code and a two-dimensional fluid code. Doublet-III is taken as an example for an open divertor configuration. A decisive parameter is the distance between the plasma surface (determined by the magnetic separatrix) and the limiter, which is varied in order to assess the interaction of the plasma with the limiter as well as the effect of neutrals on the main plasma. The minimum value of the limiter clearance needed to prevent plasma-limiter interaction is determined. The scaling of the edge temperature and the dependence of the e-folding length of the scrape-off layer plasma on the heating power are obtained. (author). 16 refs, 17 figs

Measurement with nasal scintigraphy of nasal mucociliary clearance in normal man

International Nuclear Information System (INIS)

Murai, Sumiko

1989-01-01

Nasal mucociliary function was evaluated by nasal scintigraphy in normal subjects. A microdrop of HSA or saline labelled with 99m Tc was dripped into the middle part of each middle meatus in the nasal cavity and its clearance was observed by scinticamera. The accumulated concentration of RI was determined every 30 seconds for 10 minutes. The changes of accumulated concentration were studied, and a curve of decreasing RI-counts was obtained, with the 'clearance rate' defined as 100% for the count at the initial 30 seconds and 'half time' as the time when radioactivity was reduced to one half the initial count. Nasal resistance was measured by rhinomanometry with the oscillation method. In nonsmokers, 10μl of saline was cleared (78.0±10.4%) significantly faster than 10μl of HSA (59.9±24.6%), and there was no significant difference in the clearance between 10μl and 5μl of HSA (55.9±27.7%). In smakers, the mucociliary clearance of 10μl of HSA and saline was significantly lower than in nonsmokers. The clearance of 10μl of HSA reflects a pathological state much better than that of 5μl. In nonsmokers, there is a significant negative correlation between nasal resistance and clearance rate, suggesting that the more patent the nose, the faster the mucociliary clearance. When both nostrils were closed, the clearance rate was significantly depressed. When one nostril was closed, there was no significant effect on clearance. Nasal resistance was decreased by exercise with a bicycle ergometer. Nasal mucociliary clearance was slightly decreased after exercise but not significantly so. (J.P.N.)

78 FR 77027 - Overhead Clearance (Air-Draft) Accidents

Science.gov (United States)

2013-12-20

... No. USCG-2013-0466] Overhead Clearance (Air-Draft) Accidents AGENCY: Coast Guard, DHS. ACTION... clearance (air-draft) accidents. In its petition, which calls for vessel masters to be provided with... accidents that it says were avoidable and that resulted in damage to or destruction of waterway...

The role of clearance in Germany - release of materials, buildings and sites

International Nuclear Information System (INIS)

Thierfeldt, S.

2005-01-01

Clearance in Germany is far advanced. A complex regulatory framework exists in the Radiation Protection Ordinance (RPO/Strahlenschutzverordnung, StrlSchV) since 2001 which has replaced previous recommendations on clearance issued by the German Radiation Protection Commission (Strahlenschutzkommission, SSK). A number of options exist both for unconditional clearance (e.g. of all kinds of materials with no restrictions on the destination or future use) and for clearance for a specific purpose (e.g. recycling of metal scrap). For each clearance option there is a set of nuclide specific clearance levels which have been derived on the basis of the 10 Sv/a individual dose criterion using complex radiological models which are tailored to the respective material cycles (metal scrap, buildings, building rubble, waste for disposal, sites). The clearance levels have been thoroughly reviewed by the SSK. An extensive comparison to sets of clearance levels used in other countries or issued as guidance by international bodies revealed that the correspondence between values is between good and acceptable taking into account country-specific approaches and special assumptions which would not necessarily pertain to German situations. Clearance is a major factor in the material management, especially of nuclear installations undergoing decommissioning. The variety of clearance options leaves the operator of a nuclear installation sufficient flexibility for optimisation of the material management. Clearance is of particular importance in a country like Germany where the estimated costs for a future repository are very high and the interim storage facilities for radioactive material are limited and costly. While the licensee is responsible for his material management, the issuance of a clearance permit is done by the regulatory body upon application. The regulators may choose to use the clearance levels and regulations as stipulated by the RPO, or to impose site-specific regulations on

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Full Text Available ... Make a Charitable Gift Our Corporate Supporters Workplace Engagement DONATE YOUR PROPERTY eCards for a Cure About ... airway walls. See how different airway clearance techniques work to help you clear the thick, sticky mucus ...

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Full Text Available ... people with cystic fibrosis so that they make smart decisions about CF-related research, treatment, and access ... Facebook Twitter YouTube Instagram Email DONATE Breadcrumb Navigation Home Life With CF Treatments and Therapies Airway Clearance ...

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Full Text Available ... 3-D Structure Consortium CFTR Folding Consortium Epithelial Stem Cell Consortium Mucociliary Clearance Consortium SUCCESS WITH THERAPIES RESEARCH ... ACTs involve coughing or huffing . Many of them use percussion (clapping) or vibration to loosen mucus from ...

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Full Text Available ... CFTR Modulator Therapies Mucus Thinners Nebulizer Care at Home Vascular Access Devices PICCs and Ports Partnerships for ... Facebook Twitter YouTube Instagram Email DONATE Breadcrumb Navigation Home Life With CF Treatments and Therapies Airway Clearance ...

The Use of Radioactive Marker as a Tool to Evaluate the Drug Release in Plasma and Particle Biodistribution of Block Copolymer Nanoparticles

Directory of Open Access Journals (Sweden)

Sharon Johnstone

2011-01-01

Full Text Available Diblock copolymer nanoparticles encapsulating a paclitaxel prodrug, Propac 7, have been used to demonstrate the usefulness of a nonmetabolizable radioactive marker, cholesteryl hexadecyl ether (CHE, to evaluate nanoparticle formulation variables. Since CHE did not exchange out of the nanoparticles, the rate of clearance of the CHE could be used as an indicator of nanoparticle stability in vivo. We simultaneously monitored prodrug circulation and carrier circulation in the plasma and the retention of CHE relative to the retention of prodrug in the plasma was used to distinguish prodrug release from nanoparticle plasma clearance. Nanoparticles labelled with CHE were also used to evaluate accumulation of nanoparticles in the tumour. This marker has provided relevant data which we have applied to optimise our nanoparticle formulations.

Online monitoring of dynamic tip clearance of turbine blades in high temperature environments

Science.gov (United States)

Han, Yu; Zhong, Chong; Zhu, Xiaoliang; Zhe, Jiang

2018-04-01

Minimized tip clearance reduces the gas leakage over turbine blade tips and improves the thrust and efficiency of turbomachinery. An accurate tip clearance sensor, measuring the dynamic clearances between blade tips and the turbine case, is a critical component for tip clearance control. This paper presents a robust inductive tip clearance sensor capable of monitoring dynamic tip clearances of turbine machines in high-temperature environments and at high rotational speeds. The sensor can also self-sense the temperature at a blade tip in situ such that temperature effect on tip clearance measurement can be estimated and compensated. To evaluate the sensor’s performance, the sensor was tested for measuring the tip clearances of turbine blades under various working temperatures ranging from 700 K to 1300 K and at turbine rotational speeds ranging from 3000 to 10 000 rpm. The blade tip clearance was varied from 50 to 2000 µm. The experiment results proved that the sensor can accurately measure the blade tip clearances with a temporal resolution of 10 µm. The capability of accurately measuring the tip clearances at high temperatures (~1300 K) and high turbine rotation speeds (~30 000 rpm), along with its compact size, makes it promising for online monitoring and active control of blade tip clearances of high-temperature turbomachinery.

Creatinine clearance during cimetidine administration for measurement of glomerular filtration rate

NARCIS (Netherlands)

van Acker, B. A.; Koomen, G. C.; Koopman, M. G.; de Waart, D. R.; Arisz, L.

1992-01-01

Creatinine clearance inaccurately estimates true glomerular filtration rate (GFR) because of tubular secretion of creatinine. We studied the ability of oral cimetidine, a blocker of tubular creatinine secretion, to improve the accuracy of measuring creatinine clearance. Clearances of inulin and

Intercalibration of mussel Mytilus edulis clearance rate measurements

NARCIS (Netherlands)

Kjerulf Petersen, J.; Bougrier, S.; Smaal, A.C.; Garen, P.; Robert, S.; Larsen, J.E.N.; Brummelhuis, E.B.M.

2004-01-01

Clearance rate (CR) was measured in blue mussels Mytilus edulis L. from Aiguillon Bay and the Oosterschelde using 3 different methods: the flow-through method, the bio-deposition method and the indirect or clearance method. CR differed significantly as a function of the method used and of the origin

Airway Clearance Techniques (ACTs)

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Full Text Available ... a Family Parenting as an Adult With CF Treatments and Therapies People with cystic fibrosis are living longer and ... to specialized CF care and a range of treatment options. Airway Clearance Active Cycle of Breathing Technique ...

DOD PERSONNEL CLEARANCES: Additional OMB Actions Are Needed to Improve the Security Clearance Process

National Research Council Canada - National Science Library

2006-01-01

Our independent analysis of timeliness data showed that industry personnel contracted to work for the federal government waited more than one year on average to receive top secret clearances, longer...

Effect of electric charge on the transperitoneal transport of plasma proteins during CAPD

NARCIS (Netherlands)

Buis, B.; Koomen, G. C.; Imholz, A. L.; Struijk, D. G.; Reddingius, R. E.; Arisz, L.; Krediet, R. T.

1996-01-01

BACKGROUND: Controversy exists as to whether electric charges of plasma proteins influence their transport across the peritoneal membrane during CAPD. Fixed negative charges in the peritoneal membrane are diminished during peritonitis in rats. METHODS: Peritoneal clearances of 10 proteins and their

Assessment of renal function with the Tc-99m-MAG3 clearance

International Nuclear Information System (INIS)

Keske, U.; Corcles, M.; Andreessen, R.; Wilfling, M.; Roll, D.; Gahl, G.; Felix, R.

1990-01-01

This paper evaluates the applicability of the 99m-Tc-mercaptoacetyle-triglycine (MAG3) clearance for the documentation of renal function. Renal clearance was measured with the method of Tauxe in 699 patients during routine renal scintigraphy with 80 MBq of 99mTc-MAG3. Serum creatinine level and MAG3 clearance show an inverse correlation. Patients with an elevated serum creatinine level constantly have a lowered MAG3 clearance and vice versa. For creatinine values lower than 1.8 mg/dL, minor changes in creatinine level are accompanied by large changes in MAG3 clearance. Age (in years) dependence of MAG3 clearance was evaluated in 487 patients who showed no evidence of impaired renal function

Assessment of Plasma Cystatin C among Sudanese Patients with ...

African Journals Online (AJOL)

Background: Cystatin C is mainly used as a biomarker of kidney function. It is freely filtered by glomerulus, and does not return to the blood stream or secreted by renal tubules. It has been suggested to be closer to the “ideal” endogenous marker. Objectives: To assess the plasma levels of cystatin c, creatinine clearance, ...

Effects of heart rate on myocardial thallium-201 uptake and clearance

International Nuclear Information System (INIS)

Nordrehaug, J.E.; Danielsen, R.; Vik-Mo, H.

1989-01-01

The effects of heart rate on the myocardial uptake and clearance of 201 Tl were studied prospectively in seven healthy men, mean age 43 +/- 7 (s.d.) yr. Initial and delayed (3 hr) thallium images were obtained in three views after three bicycle exercise tests: to maximal, 80% and 60% of predicted maximal heart rate. The mean of three views initial myocardial 201 Tl uptake was higher at maximal than at both 80% and 60% of predicted maximal heart rate, being 81% (p less than 0.01) and 60% (p less than 0.01) of maximal activity, respectively. The myocardial activity in the delayed images was identical. There was a linear relationship between heart rate and the initial myocardial activity, r = 0.86 (p less than 0.001). The mean (range) 201 Tl clearance was 58% (51-65), 47% (34-56), and 34% (22-49) (all differences p less than 0.01), respectively. Concordance among the three individual views in estimating clearance was best for the highest exercise level. There was a linear relationship between heart rate and clearance, r = 0.80 (p less than 0.001). Clearance was altered by only 1.67 x 10%/heart bpm (0.024 hr/heart beat). Clearance in the liver, spleen and lungs increased at submaximal exercise levels. Thus, a linear relationship between heart rate and clearance is the result of changes in the initial exercise myocardial 201 Tl activity. Submaximal exercise may reduce reproducibility of clearance estimation, and the change of myocardial clearance with heart rate seems less than previously suggested

Factors affecting lower calyceal stone clearance after Extracorporeal ...

African Journals Online (AJOL)

shanker

have been identified [1,3]. These include stone characteristics, the type of lithotripter used, LPC anatomy and body habitus. For iso- lated LPC stones, the pelvicalyceal angle, infundibulum length and width are considered important determinants for stone clearance. The impact of body habitus on stone clearance has so far ...

Delayed clearance of triglyceride‐rich lipoproteins in young, healthy obese subjects†

Science.gov (United States)

Goll, R.; Lekahl, S.; Moen, O. S.; Florholmen, J.

2015-01-01

Summary Obesity is associated with the metabolic syndrome. The aims were, first, to study the postprandial triglyceride clearance in young, healthy obese subjects and, second, to investigate if fasting triglycerides can predict delayed postprandial triglyceride clearance. Eighteen apparently healthy, obese subjects with no clinical signs of metabolic disturbances participated. Controls were age‐ and sex‐matched, healthy, normal weight subjects. Subclinical markers of metabolic disturbances were assessed by measuring postprandial triglycerides in serum and in chylomicrons by oral fat tolerance test. Postprandial triglyceride clearance for 8 h was assessed indirectly as removal of the lipid from serum during the oral fat tolerance test. Insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA‐IR). Twelve (66%) of the apparently healthy obese individuals had insulin resistance measured by HOMA‐IR. There was a delayed clearance of serum triglycerides and chylomicron triglycerides at 6 h when compared with the control group, while, at 8 h, the differences were only detected for the chylomicron triglyceride clearance. Triglyceride response was significantly greater in the obese subjects. Fasting triglycerides in upper normal level predicted a delayed postprandial triglyceride clearance and insulin resistance. In young, apparently healthy obese subjects early metabolic disturbances including insulin resistance and delayed postprandial triglyceride clearance can be detected. Fasting serum triglyceride in upper normal level predicted delayed postprandial triglyceride clearance and insulin resistance. PMID:26469529

Delayed clearance of triglyceride-rich lipoproteins in young, healthy obese subjects.

Science.gov (United States)

Larsen, M A; Goll, R; Lekahl, S; Moen, O S; Florholmen, J

2015-12-01

Obesity is associated with the metabolic syndrome. The aims were, first, to study the postprandial triglyceride clearance in young, healthy obese subjects and, second, to investigate if fasting triglycerides can predict delayed postprandial triglyceride clearance. Eighteen apparently healthy, obese subjects with no clinical signs of metabolic disturbances participated. Controls were age- and sex-matched, healthy, normal weight subjects. Subclinical markers of metabolic disturbances were assessed by measuring postprandial triglycerides in serum and in chylomicrons by oral fat tolerance test. Postprandial triglyceride clearance for 8 h was assessed indirectly as removal of the lipid from serum during the oral fat tolerance test. Insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA-IR). Twelve (66%) of the apparently healthy obese individuals had insulin resistance measured by HOMA-IR. There was a delayed clearance of serum triglycerides and chylomicron triglycerides at 6 h when compared with the control group, while, at 8 h, the differences were only detected for the chylomicron triglyceride clearance. Triglyceride response was significantly greater in the obese subjects. Fasting triglycerides in upper normal level predicted a delayed postprandial triglyceride clearance and insulin resistance. In young, apparently healthy obese subjects early metabolic disturbances including insulin resistance and delayed postprandial triglyceride clearance can be detected. Fasting serum triglyceride in upper normal level predicted delayed postprandial triglyceride clearance and insulin resistance. © 2015 World Obesity.

Dynamic characteristics analysis of deployable space structures considering joint clearance

Science.gov (United States)

Li, Tuanjie; Guo, Jian; Cao, Yuyan

2011-04-01

The clearance in joints influences the dynamic stability and the performance of deployable space structures (DSS). A virtual experimental modal analysis (VEMA) method is proposed to deal with the effects of joint clearance and link flexibility on the dynamic characteristics of the DSS in this paper. The focus is on the finite element modeling of the clearance joint, VEMA and the modal parameters identification of the DSS. The finite element models (FEM) of the clearance joint and the deployable structure are established in ANSYS. The transient dynamic analysis is conducted to provide the time history data of excitation and response for the VEMA. The fast Fourier transform (FFT) technique is used to transform the data from time domain to frequency domain. The frequency response function is calculated to identify the modal parameters of the deployable structure. Experimental verification is provided to indicate the VEMA method is both a cost and time efficient approach to obtain the dynamic characteristics of the DSS. Finally, we analyze the effects of clearance size and gravity on the dynamic characteristics of the DSS. The analysis results indicate that the joint clearance and gravity strongly influence the dynamic characteristics of the DSS.

PAH clearance after renal ischemia and reperfusion is a function of impaired expression of basolateral Oat1 and Oat3

OpenAIRE

Bischoff, Ariane; Bucher, Michael; Gekle, Michael; Sauvant, Christoph

2014-01-01

Abstract Determination of renal plasma flow (RPF) by para‐aminohippurate (PAH) clearance leads to gross underestimation of this respective parameter due to impaired renal extraction of PAH after renal ischemia and reperfusion injury. However, no mechanistic explanation for this phenomenon is available. Based on our own previous studies we hypothesized that this may be due to impairment of expression of the basolateral rate limiting organic anion transporters Oat1 and Oat3. Thus, we investigat...

32 CFR 644.522 - Clearance of military scrap.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Clearance of military scrap. 644.522 Section 644... Excess Land and Improvements § 644.522 Clearance of military scrap. Military scrap can contain or be... destruction, by using command, of all military scrap and scrap metal from lands suitable for cultivation or...

Applicability of Clearance Automatic Laser Inspection System to Clearance Measurement of Concrete Segments

International Nuclear Information System (INIS)

Sasaki, M.; Ogino, H.; Hattori, T.

2009-01-01

In the decommissioning of a nuclear power plant, large amounts of metal scrap and concrete segments require disposal when dismantling the nuclear reactor and surrounding facilities. When their activity level is negligible or sufficiently small, they can be regarded as general industrial waste. To distinguish between radioactive and nonradioactive materials, the clearance level for each radionuclide has been determined in units of activity concentration. These clearance levels are indicated in the International Atomic Energy Agency (IAEA) Safety Standards Series No. RS-G-1.7. The Japanese regulatory authority decided in 2005 to adopt the values given in RS-G-1.7 as clearance levels in legislation. Recently, a Clearance Automatic Laser Inspection System (CLALIS) has been developed utilizing gamma-ray measurement, automatic laser shape measurement and Monte Carlo calculation. CLALIS comprises four laser scanners and eight large plastic scintillation detectors surrounded by a 5-cm-thick lead shield. Using three-dimensional (3D) laser scanning, a measurement target, which is placed on the measuring tray, is represented as a dot image. The dot image is converted into voxels after noise removal, and is written in MCNP (A General Monte Carlo N-Particle Transport Code System) input files. When the gamma-ray measurement is carried out, the MCNP calculations are also carried out to obtain the calibration factor and background (BG) correction factors. For the clearance measurement of concrete segments, the effect of 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 taken into account to ensure adequate waste management. Since NE102A plastic scintillation detectors are used for gamma-ray measurement in CLALIS, it is impossible to distinguish between the count rates of natural radionuclides and contaminants on the basis of gamma-ray energy information. To overcome this problem, the

Airway Clearance Techniques (ACTs)

Medline Plus

Full Text Available ... Offer their tips for fitting ACTs into daily life Airway Clearance Techniques | Webcast To learn more about how you can help your infant or child manage their lung health, watch parents of children with CF and a respiratory therapist ...

Clearance level and industrial waste management

International Nuclear Information System (INIS)

Asano, Toichi

1999-01-01

Defining the clearance level enables the radioactive waste with lower radioactivity than a certain level to be the general industrial waste and therefore consideration for public acceptance is essential. For this, it is necessary to understand laws concerning not only atomic power and radioactivity but also disposal and cleaning of general waste. It is also necessary that the waste below the clearance level should be as much as possible handled in the modern common concept of recycling of resources. In 1996, the weight of industrial waste was about 400 million tons, of which 40% was disposed by burning and dehydration, 39% was re-used and 21% was subjected to the final disposal like reclamation. Reduction, re-use and recycling of the generated waste are required for making the society with recycling of resources. Scrap concrete materials below the clearance level of 0.6 million tons are estimated to be generated by dismantling the light water reactor of 1 million kW output and profitable technology for recycling the scrap is under investigation. (K.H.)

Factors Associated with Spontaneous Clearance of Hepatitis C Virus in Chinese Population

Directory of Open Access Journals (Sweden)

Fei Kong

2014-01-01

Full Text Available Hepatitis C virus (HCV infections spontaneously clear in approximately 15–45% of infected individuals. Factors which influence spontaneous HCV clearance remain to be identified. The purpose of the present study was to identify variables associated with spontaneous HCV clearance in a referred population of Chinese patients. The prevalence of host, viral, and environmental factors known to influence the outcome of HCV infections was compared in 92 HCV spontaneous clearance subjects and 318 HCV persistent infection subjects. Univariate and multivariate analyses were performed to identify those factors associated with spontaneous HCV clearance. In univariate analysis, female gender, a history of icteric hepatitis, serologic evidence of concurrent HBV infection, and rs12979860 CC genotype were positively associated with spontaneous HCV clearance, while alcohol consumption was negatively associated with clearance. In multivariate analysis, female gender, a history of icteric hepatitis, concurrent HBV infection, and rs12979860 CC genotype remained independent variables associated with spontaneous HCV clearance. Spontaneous HCV clearance is more likely to occur in females, subjects with a history of icteric hepatitis, HBV coinfections, and those with the rs12979860 CC genotype.

Airway Clearance Techniques (ACTs)

Medline Plus

Full Text Available ... how you can help your infant or child manage their lung health, watch parents of children with CF and a respiratory therapist talk about the different techniques they use for airway clearance. Facebook Twitter Email More Related Content Medications Autogenic Drainage ...

49 CFR 236.22 - Semaphore signal arm; clearance to other objects.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Semaphore signal arm; clearance to other objects... Rules and Instructions: All Systems Roadway Signals and Cab Signals § 236.22 Semaphore signal arm; clearance to other objects. At least one-half inch clearance shall be provided between semaphore signal arm...

Using Terrestrial Laser Scanners to Calculate and Map Vertical Bridge Clearance

Science.gov (United States)

Zhang, C.; Arditi, D.; Chen, Z.

2013-08-01

The vertical clearance of a bridge over a highway is important in preventing oversized vehicles from hitting the bridge. The vertical clearance of a bridge is traditionally measured by using surveying equipment such as leveling rods and total stations. Typically, measurements are taken at multiple locations in order to determine the minimum vertical clearance under the bridge. This process is time and labor consuming. Also, these measurements may not be accurate because of the traffic, the uneven surface, and the reading error caused by the surveyor. Additionally, when one is faced with a multitude of reports especially in large projects with multiple ramps and bridges, it is not easy and it often takes a long time to find the bridge under study. This research provides a highly accurate measurement of the vertical bridge clearance by using terrestrial laser scanners. The clearance can be measured in the office by processing the collected point cloud data. The minimum vertical clearance is easily identified and the measurement is visualized and geo-referenced. An approach to reduce data noise caused by traffic is also introduced in this study. In addition, to help reduce the confusion of finding the bridge under study and to facilitate access to the clearance data, the clearance measurements are geo-referenced to an online mapping system. This system allows access to the final deliverable very easily through a single web portal. Finally, Illinois Department of Transportation's Circle Interchange is used to demonstrate this new method.

Respiratory clearance of aerosolized radioactive solutes of varying molecular weight

International Nuclear Information System (INIS)

Huchon, G.J.; Montgomery, A.B.; Lipavsky, A.; Hoeffel, J.M.; Murray, J.F.

1987-01-01

To determine the influence of varying molecular weight (mol wt) on respiratory clearance of aerosolized solutes, we studied eight radiopharmaceuticals, each administered to four dogs: sodium /sup 99m/Tc pertechnetate (TcO4), /sup 99m/Tc glucoheptonate ([/sup 99m/Tc]GH), 51Cr-ethylenedinitrotetraacetate ([51Cr]EDTA), /sup 99m/Tc diethylenetriaminepentaacetate ([99mTc] DTPA), 111 In diethylenetriaminepentaacetate ([ 111 In]DTPA), 67 Ga desferoxaminemesylate ([ 67 Ga]DFOM), /sup 99m/Tc dextran ([/sup 99m/Tc]DX) and 111 In transferrin ([ 111 In]TF). After aerosolization (0.8 m MMD, 2.4 GSD), clearance was determined for 30 min and then corrected by intravenous injection for nonairspace radioactivity. In-TF clearance (0.11 +/- 0.10%/min) was lower than TcO4 (6.32 +/- 0.62%/min), [/sup 99m/Tc]GH (1.50 +/- 0.37%/min), [ 51 Cr]EDTA (2.38 +/- 1.02%/min), [/sup 99m/Tc]DTPA (3.51 +/- 0.40%/min), [ 111 In]DTPA (2.35 +/- 0.42%/min), [ 67 Ga] DFOM (1.99 +/- 0.49%/min) and [/sup 99m/Tc]DX (1.81 +/- 0.75%/min) clearances (p less than 0.001). TcO4 clearance was higher than others (p less than 0.001). Technetium binding to DX was unsatisfactory; aerosolization caused unbinding from DTPA. We conclude that respiratory clearance of large mol wt solutes within 30 min is negligible and, that clearance of molecules between 347-5099 daltons differs greatly, suggesting that binding and/or intrapulmonary retention affect transfer

Comparison of German and international clearance regulations - chances and limits for harmonization

International Nuclear Information System (INIS)

Thierfeldt, S.; Schartmann, F.

2005-01-01

The regulations on clearance in the German nuclear regulatory framework (especially sect. 29 and Annexes III and IV of the Radiation Protection Ordinance) are comprehensive and well founded. Germany has developed some of its clearance levels in advance of recommendations issued by the EC. Therefore, there are differences between the German and international clearance regulations. That has been investigated by a working group on clearance of the German Commission on Radiological Protection (SSK) which has performed an analysis of differences and their reasons for clearance levels in Germany and other countries (UK, The Netherlands, Sweden, USA and others). Differences can mainly be explained by country specific approaches in scenarios. Differences especially for the most relevant nuclides are not significant from a radiological point of view. The level of radiological protection (trivial dose range, a few 10 μSv/a) is guaranteed in all countries. The international discussion on the international harmonisation of clearance levels (mainly within the scope of the OECD/NEA and IAEA) can be enlightened on the basis of these results. This discussion concentrates on the question how far a harmonisation of clearance level values is actually necessary and possible. The IAEA Safety Guide RS-G-1.7 'Application of the concepts of exclusion, exemption and clearance' is of particular importance, because it proposes a set of values which might in the long-term take the role of international unconditional clearance levels. International harmonisation is only relevant for unconditional clearance of those materials, which are traded in large quantities among countries, in particular metal scrap. Harmonisation of the values to the same order of magnitude is sufficient. (orig.)

Discrepancy between circadian rhythms of inulin and creatinine clearance

NARCIS (Netherlands)

van Acker, B. A.; Koomen, G. C.; Koopman, M. G.; Krediet, R. T.; Arisz, L.

1992-01-01

To elucidate the disparity between circadian rhythmicity of inulin and creatinine clearance, we simultaneously measured inulin and creatinine clearances every 3 hours during 1 day in 14 normal subjects and in 8 patients with nephrotic syndrome. All patients and normal subjects had a circadian rhythm

Lung clearance of 99m Tc- DTPA in systemic lupus erythematous

International Nuclear Information System (INIS)

Dalcin, P.T.R; Barreto, S.S.M.; Xavier, R.M.; Brenol, J.C.T.; Cunha, R.D.; Marroni, B.J.

2002-01-01

The early demonstration of lung involvement in systemic lupus erythematosus (SLE) patients is a difficult but important task. In the present study we attempted to identify abnormalities in pulmonary clearance of 99 mTc-DTPA in SLE, correlating their clearance data with clinical findings and disease activity. Forty-six consecutive SLE patients with and without active disease (LACC score) and 30 normal volunteers were studied. All subjects were submitted to pulmonary scintigraphy with 99 mTc-DTPA to evaluate the pulmonary clearance, and to a chest X-ray, and SLE patients were submitted to tests of disease activity, spirometry, arterial blood gases and tests to assess acute-phase proteins. Pulmonary clearance was faster in SLE patients with active disease when compared to normal controls [half-life of 67.04 min (51.52-82.55 min) in active SLE versus 85.87 min (78.85-92.87 min) in controls, P<0.05] and there was a higher frequency of abnormal clearance rates in patients with active disease (11 of 26 patients, 42.3%) when compared with SLE patients without disease activity (2 of 20 patients, 10%) (P = 0.04). A significant correlation was observed between the clearance rates and cough (P<0.05), but not between the clearance rates and dyspnoea symptoms or radiological findings, duration of SLE disease, antinuclear antibody titers and patterns, C-reactive protein or anti-double stranded DNA antibodies. We conclude that the pulmonary clearance of 99 m Tc-DTPA is increased in SLE patients with active disease. (author)

Airway Clearance Techniques (ACTs)

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Full Text Available ... cystic fibrosis. CF CARE CENTER finder We provide funding for and accredit more than 120 care centers ... Community in Health Care Reform Milestones in Health Care Reform How Tax Reform Could Impact People With CF The ... Home Life With CF Treatments and Therapies Airway Clearance ...

Polymorphisms in CYP1A1 and CYP3A5 Genes Contribute to the Variability in Granisetron Clearance and Exposure in Pregnant Women with Nausea and Vomiting.

Science.gov (United States)

Bustos, Martha L; Zhao, Yang; Chen, Huijun; Caritis, Steve N; Venkataramanan, Raman

2016-12-01

Nausea and vomiting affect up to 90% of pregnant women. Granisetron is a potent and highly selective serotonin receptor antagonist and is an effective antiemetic. Findings from a prior study in pregnant women demonstrated a large interindividual variability in granisetron exposure. Granisetron is primarily metabolized by the cytochrome P450 (CYP) enzymes CYP1A1 and CYP3A and is likely a substrate of the ABCB1 transporter. Single-nucleotide polymorphisms (SNPs) in CYP3A, CYP1A1, and ABCB1 can alter drug metabolism. This study evaluated the influence of polymorphisms in CYP3A4, CYP3A5, CYP1A1, and ABCB1 on the pharmacokinetic properties of granisetron in pregnant women. The study enrolled 16 pregnant women (gestational age of 12-19 wks). All patients had nausea and vomiting and were treated with granisetron 1 mg. Granisetron plasma concentrations were determined using liquid chromatography tandem-mass spectrometry. The patients' genotype was determined using TaqMan SNP Genotyping Assays. The Hardy-Weinberg equilibrium was assessed by comparing observed and expected genotype frequencies, using the exact test. Intravenous granisetron clearance was used as the dependent variable for analysis of associations. Of 16 patients, 25% were homozygous for the allele variant CYP3A5*3 and had a significantly lower granisetron clearance and increased area under the plasma concentration-versus-time curve (AUC) compared with nonhomozygous patients. Approximately one-third of patients (n=5) were carriers for the allele variant CYP1A1*2A and had a significantly higher granisetron clearance and decreased AUC. We did not find significant differences in the AUC or clearance for any SNPs in CYP3A4 and ABCB1 genes. Polymorphisms in CYP3A5 and CYP1A1 account for some of the variability in systemic clearance and exposure of granisetron in pregnant women. © 2016 Pharmacotherapy Publications, Inc.

PAH clearance after renal ischemia and reperfusion is a function of impaired expression of basolateral Oat1 and Oat3.

Science.gov (United States)

Bischoff, Ariane; Bucher, Michael; Gekle, Michael; Sauvant, Christoph

2014-02-01

Determination of renal plasma flow (RPF) by para-aminohippurate (PAH) clearance leads to gross underestimation of this respective parameter due to impaired renal extraction of PAH after renal ischemia and reperfusion injury. However, no mechanistic explanation for this phenomenon is available. Based on our own previous studies we hypothesized that this may be due to impairment of expression of the basolateral rate limiting organic anion transporters Oat1 and Oat3. Thus, we investigated this phenomenon in a rat model of renal ischemia and reperfusion by determining PAH clearance, PAH extraction, PAH net secretion, and the expression of rOat1 and rOat3. PAH extraction was seriously impaired after ischemia and reperfusion which led to a threefold underestimation of RPF when PAH extraction ratio was not considered. PAH extraction directly correlated with the expression of basolateral Oat1 and Oat3. Tubular PAH secretion directly correlated with PAH extraction. Consequently, our data offer an explanation for impaired renal PAH extraction by reduced expression of the rate limiting basolateral organic anion transporters Oat1 and Oat3. Moreover, we show that determination of PAH net secretion is suitable to correct PAH clearance for impaired extraction after ischemia and reperfusion in order to get valid results for RPF.

48 CFR 32.502-2 - Contract finance office clearance.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contract finance office clearance. 32.502-2 Section 32.502-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... finance office clearance. The contracting officer shall obtain the approval of the contract finance office...

48 CFR 832.502-2 - Contract finance office clearance.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract finance office clearance. 832.502-2 Section 832.502-2 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS... finance office clearance. Contracting officers must obtain approval from the DSPE before taking the...

Secretion clearance strategies in Australian and New Zealand Intensive Care Units.

Science.gov (United States)

Ntoumenopoulos, George; Hammond, Naomi; Watts, Nicola R; Thompson, Kelly; Hanlon, Gabrielle; Paratz, Jennifer D; Thomas, Peter

2017-06-26

To describe the processes of care for secretion clearance in adult, intubated and mechanically ventilated patients in Australian and New Zealand Intensive Care Units (ICUs). A prospective, cross-sectional study was conducted through the Australian and New Zealand Intensive Care Society Clinical Trials Group (ANZICS CTG) Point Prevalence Program. Forty-seven ICUs collected data from 230 patients intubated and ventilated on the study day. Secretion clearance techniques beyond standard suctioning were used in 84/230 (37%) of patients during the study period. Chest wall vibration 34/84 (40%), manual lung hyperinflation 24/84 (29%), chest wall percussion 20/84 (24%), postural drainage/patient positioning 17/84 (20%) and other techniques including mobilisation 15/84 (18%), were the most common secretion clearance techniques employed. On average (SD), patients received airway suctioning 8.8 (5.0) times during the 24-h study period. Mucus plugging events were infrequent (2.7%). The additional secretion clearance techniques were provided by physiotherapy staff in 24/47 (51%) ICUs and by both nursing and physiotherapy staff in the remaining 23/47 (49%) ICUs. One-third of intubated and ventilated patients received additional secretion clearance techniques. Mucus plugging events were infrequent with these additional secretion clearance approaches. Prospective studies must examine additional secretion clearance practices, prevalence of mucus plugging episodes and impact on patient outcomes. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Influence of peak exercise heart rate on normal thallium-201 myocardial clearance

International Nuclear Information System (INIS)

Kaul, S.; Chesler, D.A.; Pohost, G.M.; Strauss, H.W.; Okada, R.D.; Boucher, C.A.

1986-01-01

Measurement of myocardial clearance rates between initial and delayed images is a major justification for adding computer quantification to the interpretation of exercise 201 TI images. To clarify the range of normal thallium clearance and its relationship to the level of exercise achieved, exercise thallium images in 89 normal subjects were analyzed: 45 asymptomatic subjects with less than 1% probability of coronary artery disease (CAD) (Group I), and 44 patients with chest pain found to have no significant CAD on angiography (Group II). Mean initial regional thallium uptake was similar in the two groups, but myocardial thallium clearance (mean +/- 1 s.d.) was slower in Group II, expressed as a longer half-life in the myocardium (8.2 +/- 7.6 hr compared with 3.4 +/- 0.7 hr p less than 0.001). Analysis of variance using ten clinical and exercise variables as covariates showed that the slower clearance in Group II was related to a lower peak exercise heart rate (HR) (154 +/- 27 compared with 183 +/- 11, respectively, p less than 0.001). By linear regression analysis, a decrease in peak HR of 1 beat/min was associated with a slower thallium clearance (longer half-life) of 0.05 hr. Using this formula, the clearance value in each patient was then corrected for peak exercise heart rate by decreasing measured clearance by 0.05 hr multiplied by the amount peak exercise heart rate which was below 183 (the mean value in Group I). There were no differences in the corrected clearance between the two groups. We conclude that thallium myocardial clearance after exercise is related in part to factors other than the presence of CAD, being slower when peak exercise HR is lower. Therefore, thallium clearance rates alone uncorrected for peak exercise heart rate should be used with caution when diagnosing CAD

A Study to Determine Clearance Levels of Radioactive Wastes in Kenya

Energy Technology Data Exchange (ETDEWEB)

Mukakaa, Zaphania O. [KAIST, Daejeon (Korea, Republic of); Kim, Sung Il [KINS, Daejeon (Korea, Republic of)

2015-10-15

Due to lack of a radioactive waste disposal facility in Kenya, radioactive wastes are stored in a bonded warehouse until such a time when their activity is low and they meet the criterion for clearance. The International Atomic Energy Agency (IAEA) has established activity concentrations of radionuclides to act as a universal guideline or standard for clearance in member countries. Radioactive wastes whose activity would yield a trivial risk to the people and environment, i.e. with an annual dose below 10 µSv are usually cleared from regulatory control with no further regulatory control mechanisms being taken. The Radiation Protection Board currently depends on the IAEA's generic clearance level activity concentrations for purposes of clearing the radiation wastes within its inventory. This study aims to determine activity concentrations of radionuclides in the Kenyan inventory that correspond to the clearance level dose of 10 µSv/a as set by the IAEA. The RESidual RADioactivity (RESRAD) computer code, an important tool developed in 1989 to aid in evaluation of sites with radioactive contamination, will aid in modeling these clearance level values using a pathways analysis method and available site-specific data from Kenya. Afterwards, the obtained clearance level values will be compared with the IAEA's generic clearance level values of the corresponding radionuclides. The results modeled using the RESRAD code are conservative. For most of the radionuclides in the Kenyan inventory, the values do correspond with the IAEA standard generic clearance level values, albeit with minor differences. For most of the radionuclides, the difference is within the acceptable uncertainty limit. For these low probability events the effective dose resulting from them should not exceed 1 mSv per year. Thus, consideration was given to doses to the skin and an equivalent dose to the skin of 50 mSv per year was duly used in estimating the clearance level activities. The

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

Directory of Open Access Journals (Sweden)

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.

Effect of glucose-insulin-potassium infusion on thallium myocardial clearance

International Nuclear Information System (INIS)

Wilson, R.A.; Okada, R.D.; Strauss, H.W.; Pohost, G.M.

1983-01-01

Factors influencing the rate of 201 Tl clearance from the myocardium have not been clearly defined. This study determined the effect of an intravenous infusion of glucose-insulin-potassium (GIK) on the net 201 Tl clearance rates from myocardium with and without initial 201 Tl loading. Anesthetized open-chest dogs underwent 5 min of left anterior descending coronary artery occlusion and intravenous 201 Tl was injected and the occlusion released 5 min later. Thirty minutes after 201 Tl injection, 30 ml of either GIK (nine dogs) or saline (five dogs) was infused intravenously. The clearance rates of 201 Tl from the anterior wall (without initial 201 Tl loading) and from the posterior wall (with initial 201 Tl loading) were monitored with miniaturized cadmium telluride detectors placed on the myocardium. Calculation of net myocardial clearance rates was performed by linear regression analysis from serial 1 min counts. Compared with saline infusion, GIK increased the net clearance of 201 Tl from both myocardial regions with and without initial loading. The most marked change induced by GIK infusion was in the myocardial region without initial 201 Tl loading; a net increase in 201 Tl activity (72 +/- 42 cpm/30 min) was converted into a net loss (-594 +/- 228 cpm/30 min). There was no significant change in 201 Tl clearance after the saline infusion. Heart rate, aortic and left atrial pressure, sonomicrometer-measured transmural myocardial wall thickness, microsphere-determined myocardial blood flow, and blood glucose and potassium concentrations did not change significantly during GIK or saline infusions. Thus, GIK infusion appears to increase net 201 Tl clearance from myocardial zones with and without initial 201 Tl loading

Trimerization of apolipoprotein A-I retards plasma clearance and preserves antiatherosclerotic properties

DEFF Research Database (Denmark)

Graversen, Jonas Heilskov; Laurberg, Jacob Marsvin; Andersen, Mikkel Holmen

2008-01-01

An increased plasma level of the major high-density lipoprotein (HDL) component, apolipoprotein A-I (apoA-I) is the aim of several therapeutic strategies for combating atherosclerotic disease. HDL therapy by direct intravenous administration of apoA-I is a plausible way; however, a fast renal...

48 CFR 1432.502-2 - Contract finance office clearance.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract finance office clearance. 1432.502-2 Section 1432.502-2 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR... finance office clearance. The CO shall obtain approval of the bureau finance office prior to taking...

Determining vancomycin clearance in an overweight and obese population.

Science.gov (United States)

Leong, Julie V B; Boro, Maureen S; Winter, Michaele

2011-04-01

Two methods of calculating vancomycin clearance were compared to determine the best body weight measure to use when dosing vancomycin for overweight and obese patients. Hospitalized veterans weighing more than 120% of their ideal body weight (IBW) with serum vancomycin concentrations (SVCs) drawn between January 1, 2003, and June 30, 2005, were eligible for study inclusion. Exclusion criteria included weight of more than 300% the IBW, unstable renal function, dialysis, uncertain vancomycin dosing or sampling times, and distribution-phase sampling. Data from January 1 through December 31, 2003 (phase 1) determined the best-fit weight for vancomycin clearance for the Leonard and Boro method. The bias and precision of the modified Leonard and Boro method using the best-fit weight for vancomycin clearance were then compared with those of the Rushing and Ambrose method for predicting SVCs from January 1, 2004, through June 30, 2005 (phase 2). Forty-eight patients were included in phase 1, with 67 SVCs for analysis. During phase 1, adjusted body weight (ABW), using the Leonard and Boro method, was superior in predicting vancomycin clearance and the resultant SVCs. A total of 96 patients were included in phase 2 of the study, with 160 SVCs for analysis. The modified Leonard and Boro method was significantly more precise than the Rushing and Ambrose method in predicting vancomycin clearance. Use of ABW proved to be superior compared with total body weight when estimating vancomycin clearance in overweight and obese patients. While there was no difference in bias between methods, the modified Leonard and Boro method was significantly more precise than the Rushing and Ambrose method in predicting SVCs when dosing vancomycin for obese patients.

Tip clearance effect on through-flow and performance of a centrifugal compressor

International Nuclear Information System (INIS)

Eum, Hark Jin; Kang, Young Seok; Kang, Shin Hyoung

2004-01-01

Numerical simulations have been performed to investigate tip clearance effect on through-flow and performance of a centrifugal compressor which has the same configuration of impeller with six different tip clearances. Secondary flow and loss distribution have been surveyed to understand the flow mechanism due to the tip clearance. Tip leakage flow strongly interacts with mainstream flow and considerably changes the secondary flow and the loss distribution inside the impeller passage. A method has been described to quantitatively estimate the tip clearance effect on the performance drop and the efficiency drop. The tip clearance has caused specific work reduction and additional entropy generation. The former, which is called inviscid loss, is independent of any internal loss and the latter, which is called viscous loss, is dependent on every loss in the flow passage. Two components equally affected the performance drop as the tip clearances were small, while the efficiency drop was influenced by the viscous component alone. The additional entropy generation was modeled with all the kinetic energy of the tip leakage flow. Therefore, the present paper can provide how to quantitatively estimate the tip clearance effect on the performance and efficiency

Tear clearance implications for ocular surface health.

Science.gov (United States)

de Paiva, Cintia Sade; Pflugfelder, Stephen C

2004-03-01

Tear clearance/turnover provides a global assessment of the function of the lacrimal functional unit and of tear exchange on the ocular surface. It is an indirect measure of dry eye induced inflammation on the ocular surface. It shows better correlation with the severity of ocular irritation symptoms and corneal epithelial disease in dry eye than the Schirmer 1 test. Delayed tear clearance may prove to be the best measure for identifying patients with tear film disorders who may respond to anti-inflammatory therapy.

Clearance of Tc-99m DTPA in hemodialysis and peritoneal dialysis: concise communication

International Nuclear Information System (INIS)

Wainer, E.; Boner, G.; Lubin, E.; Rosenfeld, J.B.

1981-01-01

The clearance of Tc-99m DTPA was studied in 14 patients undergoing hemodialysis (HD) or peritoneal dialysis (PD). Mean Tc-99m DTPA clearance during HD was 37.8% +/- 10.1 of creatinine clearance. Mean Tc-99m DTPA clearance in PD was 65.1% +/- 10.3 of creatinine clearance. Tc-99m DTPA, with a larger molecular weight than that of creatinine, is cleared relatively better during PD than during HD. Thus Tc-99m DTPA may be used in the assessment of the effectiveness of different dialytic treatments for substances of similar molecular weight. In addition, our study shows that clearance of DTPA both in HD and PD is sufficiently high to allow the removal of this chelating agent in patients with renal failure

Effect of isolated hepatic ischemia on organic anion clearance and oxidative metabolism.

Science.gov (United States)

Minard, G; Bynoe, R; Wood, G C; Fabian, T C; Croce, M; Kudsk, K A

1992-04-01

Hepatic failure is frequently seen following severe hemorrhagic shock, sepsis, and trauma. Clearance of various drugs has been used to evaluate hepatocellular dysfunction, including indocyanine green (ICG), an organic anionic dye that is transported similarly to bilirubin, and antipyrine (AP), a marker of oxidative phosphorylation. Previous investigators have noted a decrease in ICG excretion following systemic hemorrhage. The effect of isolated hepatic ischemia on the clearances of ICG and AP was studied in 16 pigs after 90 minutes of vascular occlusion to the liver. Antipyrine clearance decreased almost 50% from baseline values at 24 and 72 hours after the ischemia procedure, indicating a significant depression in the cytochrome P-450 system. On the other hand, ICG clearance did not change significantly. In conclusion, ICG clearance is not depressed after isolated hepatic ischemia in pigs. Changes in organic anion clearance after systemic hemorrhage may be because of release of toxic products from ischemic peripheral tissue.

Clearance of 99mTc-DTPA and experimentally increased alveolar surfactant content

International Nuclear Information System (INIS)

Bos, J.A.H.; Wollmer, P.; Bakker, W.; Hannappel, E.; Lachmann, B.

1992-01-01

The authors measured clearance of 99m Tc-labeled diethylenetriamine pentaacetic acid ( 99m Tc-DTPA) in rabbits with experimentally increased alveolar surfactant content. In one group of animals, surfactant production was increased by treatment with ambroxol, and another group of animals was treated with tracheal instillation of natural surfactant. A group of untreated control animals and animals treated with instillation of saline were also studied. Clearance was measured during standard conditions of mechanical ventilation and during ventilation with large tidal volumes. In ambroxol- and surfactant-treated groups, clearance rate was reduced compared with untreated control animals. In contrast, clearance rate increased after saline instillation. The differences were observed at both modes of ventilation. The findings indicate that the pulmonary surfactant system is a rate-limiting factor for the clearance of 99m Tc-DTPA and that the volume dependence of clearance is not explained by stretching of the alveolar wall only. 28 refs., 2 figs., 1 tab

A specific radioenzymatic assay for dihydroxyphenylalanine (DOPA). Plasma DOPA may be the precursor of urine free dopamine

International Nuclear Information System (INIS)

Brown, M.J.; Dollery, C.T.

1981-01-01

A sensitive radioenzymatic assay was developed, in which DOPA is enzymatically decarboxylated to dopamine and the latter converted to [ 3 H]-methoxytryamine in the presence of [ 3 H]-S-adenosyl-L-methionine and catechol-o-methyltransferase. The assay was specific for DOPA, and was sensitive to 50 pg/ml. Endogenous DOPA was found to be present in the plasma of eight human volunteers at a concentration of 10.46 +- 2.42 nmol/l. Simultaneous urine collections in the same subjects showed a free dopamine excretion of 68.88 +- 17.70 nmol/h. There was a significant correlation (P < 0.01) between plasma DOPA concentration and urine free dopamine excretion (r = 0.84). After the oral administration of 250 mg levodopa, plasma DOPA and urine dopamine both increased by a similar proportion (98 +- 8.4-fold, and 93.4 +- 6.9-fold respectively). These compare with an increase in plasma dopamine of only 26 +- 15-fold (P<0.01). Following the oral dose of DOPA, the increase in plasma DOPA, but not plasma dopamine, could account for the increase in urine dopamine. The calculated clearance of plasma DOPA by renal decarboxylation to dopamine was 114 +- 20 ml/min. This is not significantly different from the apparent clearance of endogenous DOPA by renal decarboxylation to dopamine, and suggests that there is adequate renal decarboxylase activity for DOPA to be the precursor for renal dopamine formation. (author)

Domiciliary humidification improves lung mucociliary clearance in patients with bronchiectasis.

Science.gov (United States)

Hasani, A; Chapman, T H; McCool, D; Smith, R E; Dilworth, J P; Agnew, J E

2008-01-01

Inspired air humidification has been reported to show some benefit in bronchiectatic patients. We have investigated the possibility that one effect might be to enhance mucociliary clearance. Such enhancement might, if it occurs, help to lessen the risks of recurrent infective episodes. Using a radioaerosol technique, we measured lung mucociliary clearance before and after 7 days of domiciliary humidification. Patients inhaled high flow saturated air at 37 degrees C via a patient-operated humidification nasal inhalation system for 3 h per day. We assessed tracheobronchial mucociliary clearance from the retention of (99m)Tc-labelled polystyrene tracer particles monitored for 6 h, with a follow-up 24-h reading. Ten out of 14 initially recruited patients (age 37-75 years; seven females) completed the study (two withdrew after their initial screening and two prior to the initial clearance test). Seven patients studied were non-smokers; three were ex-smokers (1-9 pack-years). Initial tracer radioaerosol distribution was closely similar between pre- and post-treatment. Following humidification, lung mucociliary clearance significantly improved, the area under the tracheobronchial retention curve decreased from 319 +/- 50 to 271 +/- 46%h (p humidification treatment improved lung mucociliary clearance in our bronchiectatic patients. Given this finding plus increasing laboratory and clinical interest in humidification mechanisms and effects, we believe further clinical trials of humidification therapy are desirable, coupled with analysis of humidification effects on mucus properties and transport.

48 CFR 245.7101-4 - DD Form 1640, Request for Plant Clearance.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false DD Form 1640, Request for Plant Clearance. 245.7101-4 Section 245.7101-4 Federal Acquisition Regulations System DEFENSE... Forms 245.7101-4 DD Form 1640, Request for Plant Clearance. Use to request plant clearance assistance or...

Impairment of nasal mucociliary clearance in woodworkers in the furniture industry

Science.gov (United States)

Black, A.; Evans, J. C.; Hadfield, Esme H.; Macbeth, R. G.; Morgan, A.; Walsh, M.

1974-01-01

Black, A., Evans, J. C., Hadfield, Esme H., Macbeth, R. G., Morgan, A., and Walsh, M. (1974).British Journal of Industrial Medicine,31, 10-17. Impairment of nasal mucociliary clearance in woodworkers in the furniture industry. Measurements of mucociliary clearance from the anterior end of the middle turbinate were made using technetium-99m-labelled particles in nine woodworkers from the furniture industry and in 12 controls, none of whom had been occupationally exposed to wood dust. Clearance rates in the controls ranged from 1·9 to 18·5 mm min-1 with a mean of 6·8. These values are in good agreement with measurements reported elsewhere for normal subjects. Only one of the woodworkers had a clearance rate which fell within the normal range and he had been occupationally exposed for the shortest period (6 years). In four woodworkers clearance was very slow (furniture industry for more than 10 years. PMID:4821406

Renal clearance of 99mTc-methylene-diphosphonate in human beings

International Nuclear Information System (INIS)

Vattimo, A.

1987-01-01

The renal clearance of 99m Tc-MDP was measured in 13 patients who had bone scans and compared with the renal clearance of 51 Cr-EDTA. No difference was found between the renal clearance of the two tracers, showing a close correlation (r = 0.98). These data suggest that the 99m Tc-MDP is excreted by the kidneys by glomerular filtration without tubular secretion. (orig.) [de

Exercise increases the lung clearance of inhaled Tc-99m DTPA

International Nuclear Information System (INIS)

Meignan, M.; Rosso, J.; Cinotti, L.; Galle, P.

1985-01-01

It has been suggested that blood flow have little effect on the lung clearance of Tc-99m DTPA which depends on the alveolar distension. However an increase of pulmonary blood flow, induces a recruitment of new vascular areas which can enhance this clearance. To assess this hypothesis the pulmonary apical and basal clearances of a sumicronic aerosol of Tc-99m DTPA were studied at rest and at exercise in seven non smoking volunteers in upright posture. As a matter of fact exercising upright is known to increase primarily the apical blood flow. After inhalation the subjects were seated on a bicycle their back against a gamma camera which was linked to a computer. The lung radioactivity was registered successively during a resting and an exercising period. At rest there was a gradient of clearance from the apex to the base of the lung, the apical clearance being significantly higher. At exercise (50 Watts, 60 c. min /sup -1/, 7 min.) this regional gradient was enhanced by a large and significant increase of the apical clearances (0.0340 min /sup -1/ +-0.0063 SD versus 0.00183 min /sup -1/ +- 0.074 SD at rest, n = 7, p < 0.01). By contrast the changes of the basal clearances were slight and unsignificant (0.0146 min /sup -1/ +- 0.0062 SD versus 0.0140 min /sup -1/ +- 0.0082 SD). Since exercise induces little distension of the apical alveoli but drastically enhances the apical blood flow, the observed increase of the apical lung clearance could be primarily attributed to the recruitment of new capillaries induced by exercise in the apices. This led to an increase of the surface area permeability product

Constitutive androstane receptor activation promotes bilirubin clearance in a murine model of alcoholic liver disease.

Science.gov (United States)

Wang, Xiuyan; Zheng, Liyu; Wu, Jinming; Tang, Binbin; Zhang, Mengqin; Zhu, Debin; Lin, Xianfan

2017-06-01

Increased plasma levels of bilirubin have been reported in rat models and patients with alcoholic liver disease (ALD). The constitutive androstane receptor (CAR) is a known xenobiotic receptor, which induces the detoxification and transport of bilirubin. In the present study, the bilirubin transport regulatory mechanisms, and the role of CAR activation in hepatic and extrahepatic bilirubin clearance were investigated in a murine model of ALD. The mice were fed a Lieber-DeCarli ethanol diet or an isocaloric control diet for 4 weeks, followed by the administration of CAR agonists, 1,4-bis-[2‑(3,5-dichlorpyridyloxy)]benzene (TCPOBOP) and phenobarbital (PB), and their vehicles to examine the effect of the pharmacological activation of CAR on serum levels of bilirubin and on the bilirubin clearance pathway in ALD by serological survey, western blotting and reverse transcription‑quantitative polymerase chain reaction. The results showed that chronic ethanol ingestion impaired the nuclear translocation of CAR, which was accompanied by elevated serum levels of bilirubin, suppression of the expression of hepatic and renal organic anion transporting polypeptide (OATP) 1A1 and hepatic multidrug resistance‑associated protein 2 (MRP2), and induction of the expression of UDP-glucuronosyltransferase (UGT) 1A1. The activation of CAR by TCPOBOP and PB resulted in downregulation of the serum levels of bilirubin followed by selective upregulation of the expression levels of OATP1A1, OATP1A4, UGT1A1 and MRP2 in ALD. These results revealed the bilirubin transport regulatory mechanisms and highlighted the importance of CAR in modulating the bilirubin clearance pathway in the ALD mouse model.

Oxygen Tension Beneath Scleral Lenses of Different Clearances.

Science.gov (United States)

Giasson, Claude J; Morency, Jeanne; Melillo, Marc; Michaud, Langis

2017-04-01

To evaluate the relative partial pressure in oxygen (pO2) at the corneal surface under Boston XO2 scleral lenses (SL) fitted with targeted clearances of 200 and 400 μm (SL200 and SL400). During this prospective study, the right eyes of eight normal subjects were fitted with SL200 and SL400. Clearance, validated after 5 minutes of wear with an optical coherence tomograph, was used with lens thicknesses to calculate transmissibility and estimate pO2. Corneal pO2s were measured with an oxygen electrode after 5 minutes of (1) corneal exposure to calibrating gases with various pO2 or of (2) SL wear. Decays in pO2 were modeled to an exponential. Linear regression between exponent k of these decays and calibrating gas pO2s allowed for the calculation of corneal pO2 under SL. Differences between pO2s beneath SL200 and SL400 were tested with a mixed ANOVA. The estimated transmissibility based on thicknesses and clearances (239.7 ± 34.7; 434.5 ± 33.2 μm) predicted a corneal pO2 of 8.52 ± 0.51 and 6.37 ± 0.28% for SL200 and SL400. These values were close to measured pO2: 9.07 ± 0.86 and 6.19 ± 0.87% (mean ± SEM) (P time, an 18-mm scleral lens fitted with a 400-μm clearance reduces the oxygen tension available to the cornea by 30% compared to a similar lens fitted with a 200-μm clearance after 5 minutes of wear.

Monoexponential analysis of plasma disappearance of 99mTc-DTPA and 131I-iodohippurate: A reliable method for measuring changes of renal function

International Nuclear Information System (INIS)

Clifton, G.G.; Anderson, C.; McMahon, G.; Vargas, R.; Wallin, J.D.

1989-01-01

Glomerular filtration rate and effective renal plasma flow were measured in 170 subjects using monoexponential analysis of plasma disappearance curves for 99m Tc-DTPA and 131 I-iodohippurate after single injection. In the current study population, glomerular filtration rate and effective renal plasma flow decreased with increasing age, were less in females than in males, and were less in hypertensives than in normotensives. Differences in glomerular filtration rate according to age and sex in the current study were similar to those reported using traditional creatinine clearance methodology. Monoexponential treatment of plasma isotope disappearance gave reproducible values for both glomerular filtration rate and effective renal plasma flow when measured either during the day or on a daily basis. Intraindividual coefficient of variation was less than 10% for both 99m Tc-DTPA and 131 I-iodohippurate clearances derived from monoexponential analysis. These results demonstrate that monoexponential analysis of plasma disappearance curves for 99m Tc-DTPA and 131 I-iodohippurate after a single injection is a useful method for evaluating changes in renal hemodynamics either during chronic drug therapy or acutely after single dose administration

Acute exposure to acid fog. Effects on mucociliary clearance

International Nuclear Information System (INIS)

Laube, B.L.; Bowes, S.M. III; Links, J.M.; Thomas, K.K.; Frank, R.

1993-01-01

Submicrometric sulfuric acid (H2SO4) aerosol can affect mucociliary clearance without eliciting irritative symptoms or changes in pulmonary function. The effect of larger fog droplets containing H2SO4 on mucociliary clearance is unknown. We quantified mucociliary clearance from the trachea (n = 4) and small airways (n = 7) of young healthy male adults after an acute exposure to H2SO4 fog (MMAD = 10.3 microns; pH = 2.0; liquid water content = 481 +/- 65 mg/m3; osmolarity = 30 mOsm). Acid fog (AF) or saline fog (SF) (10.9 microns; 492 +/- 116 mg/m3; 30 mOsm) was administered for 40 min of unencumbered breathing (no mouth-piece) at rest and for 20 min of exercise sufficient to produce oronasal breathing. Fog exposures were followed by a methacholine (MCh) challenge (a measure of airway reactivity) or inhalation of technetium-99M radioaerosol (MMAD = 3.4 microns) on 2 study days each. Changes in symptoms and forced ventilatory function were also assessed. Clearance was quantified from computer-assisted analyses of gamma camera images of the lower respiratory tract in terms of %removal/min of the radiolabel from the trachea 25 min after inhalation and from the outer zone of the right lung after 1.9 to 3 h. Symptoms, forced ventilatory function, and MCh response were unaffected by either fog. Tracheal clearance was more rapid in four of four subjects after AF (0.83 +/- 1.58% removal/min) compared with that after SF (-0.54 +/- 0.85% removal/min). Outer zone clearance was more rapid in six of seven subjects after AF (0.22 +/- 0.15% removal/min) compared with that after SF (0.01 +/- 0.09% removal/min)

20 CFR 655.150 - Interstate clearance of job order.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Interstate clearance of job order. 655.150... job order. (a) SWA posts in interstate clearance system. The SWA must promptly place the job order in... transmit a copy of its active job order to all States listed in the job order as anticipated worksites...

HPT Clearance Control: Intelligent Engine Systems-Phase 1

Science.gov (United States)

2005-01-01

The following work has been completed to satisfy the Phase I Deliverables for the "HPT Clearance Control" project under NASA GRC's "Intelligent Engine Systems" program: (1) Need for the development of an advanced HPT ACC system has been very clearly laid out, (2) Several existing and potential clearance control systems have been reviewed, (3) A scorecard has been developed to document the system, performance (fuel burn, range, payload, etc.), thermal, and mechanical characteristics of the existing clearance control systems, (4) Engine size and flight cycle selection for the advanced HPT ACC system has been reviewed with "large engine"/"long range mission" combination showing the most benefit, (5) A scoring criteria has been developed to tie together performance parameters for an objective, data driven comparison of competing systems, and (6) The existing HPT ACC systems have been scored based on this scoring system.

Plasma exogenous creatinine excretion for the assessment of renal function in avian medicine--pharmacokinetic modeling in racing pigeons (Columba livia).

Science.gov (United States)

Scope, Alexandra; Schwendenwein, Ilse; Schauberger, Günther

2013-09-01

The diagnostic evaluation of the glomerular filtration rate by urinary clearance has significant practical limitations in birds because urine is excreted together with feces. Thus, pharmacokinetic modeling of an exogenous plasma creatinine clearance could be useful for assessing renal creatinine excretion in birds. For this study, creatinine (50 mg/kg) was administered to 2 groups of 15 pigeons (Columba livia) each; in one group by the intravenous (IV) route and in the second by the intramuscular (IM) route. The time series of the plasma creatinine concentrations were analyzed by pharmacokinetic models. Body mass-specific creatinine excretion was determined for IV and IM administration to be between 6.30 and 6.44 mL/min per kg, respectively. Body surface area-specific creatinine clearance, which is related to the metabolic rate, was calculated between 0.506 and 0.523 mL/min per dm2, respectively. The results showed that IV as well as IM administration can be used for assessing renal creatinine excretion in pigeons. For practical reasons, IM administration is recommended, with the use of the Bateman function to calculate creatinine elimination.

32 CFR 154.16 - Security clearance.

Science.gov (United States)

2010-07-01

... part. The Director, Washington Headquarters Services (WHS) will initiate the required investigation... clearance, as appropriate. The Assistant Secretary of Defense (Legislative Affairs) will be notified by WHS...

Estimation of normal chromium-51 ethylene diamine tetra-acetic acid clearance in children

International Nuclear Information System (INIS)

Piepsz, A.; Pintelon, H.; Ham, H.R.

1994-01-01

In order to estimate the normal range of chromium-51 ethylene diamine tetra-acetic acid (EDTA) clearance in children, we selected a series of 256 patients with past or present urinary tract infection who showed, at the time of the clearance determination, normal technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy and normal left to right DMSA relative uptake. The clearance was calculated by means of either the simplified second exponential method or the 120-min single blood sample; Chantler's correction was used in order to correct for having neglected the first exponential. There was a progressive increase in clearance from the first weeks of life (mean value around 1 month: 55 ml/min/1.73 m 2 ), with a plateau at around 18 months. Between 2 and 17 years of age, the clearance values remained constant, with a mean value of 114 ml/min/1.73 m 2 (SD: 24 ml/min); this is similar to the level described for inulin clearance. No significant differences were observed between boys and girls, or between clearance values calculated with one or with two blood samples. Taking into account the hour of intravenous injection of the tracer, we did not observe any influence of the lunchtime meal on the distribution of the 51 Cr-EDTA clearance values. (orig.)

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

International Nuclear Information System (INIS)

Vissing, J.; Ohkuwa, Tetsuo; Ploug, T.; Galbo, H.

1988-01-01

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-[ 3 H]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

Analysis of foot clearance in firefighters during ascent and descent of stairs.

Science.gov (United States)

Kesler, Richard M; Horn, Gavin P; Rosengren, Karl S; Hsiao-Wecksler, Elizabeth T

2016-01-01

Slips, trips, and falls are a leading cause of injury to firefighters with many injuries occurring while traversing stairs, possibly exaggerated by acute fatigue from firefighting activities and/or asymmetric load carriage. This study examined the effects that fatigue, induced by simulated firefighting activities, and hose load carriage have on foot clearance while traversing stairs. Landing and passing foot clearances for each stair during ascent and descent of a short staircase were investigated. Clearances decreased significantly (p < 0.05) post-exercise for nine of 12 ascent parameters and increased for two of eight descent parameters. Load carriage resulted in significantly decreased (p < 0.05) clearance over three ascent parameters, and one increase during descent. Decreased clearances during ascent caused by fatigue or load carriage may result in an increased trip risk. Increased clearances during descent may suggest use of a compensation strategy to ensure stair clearance or an increased risk of over-stepping during descent. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Activation and clearance of vanadium alloys and beryllium multipliers in fusion reactors

International Nuclear Information System (INIS)

Bartenev, S.; Romanovskij, V.; Ciampichetti, A.; Zucchetti, M.; Forrest, R.; Kolbasov, B.; Romanov, P.

2006-01-01

Design of fusion reactors includes the development of low-activation materials. V-Cr-Ti alloys are among the candidate structural materials for the first wall and blanket, with the scarce and costly V as the main component. It is worth considering its regeneration and refabrication as well as to avoid its disposal as radioactive waste. However, to do so, it is necessary to bring its radioactivity down to sufficiently low levels. We have two possible goals: · Recycling (within the nuclear industry) for first wall and front blanket components. In that case, contact dose rate must be sufficiently low. · Clearance (release from nuclear regulatory control) for back blanket and backplate components. In that case, the clearance index must be below unity. In fact, for components less exposed to neutron activation, clearance may be reachable, after a conceivable period of decay. Maximum radionuclide concentrations in the alloys allowing their clearance were determined, using new IAEA Clearance Limits. For this purpose, also for less neutron-exposed structures, such as the back part of the blanket and the backplate, clearance is possible only if certain activation products are separated. As for recycling within the nuclear industry of first wall components, also for clearance it turns out that the development of isotope chemical separation techniques is interesting and necessary for our purposes. A suitable method for achieving the required substantial radioactivity reduction of activated V-Cr-Ti alloys is radiochemical extraction reprocessing, Such a technology, permitting to remove metallic activation products from spent materials, was developed and tested experimentally in Russia. Concerning clearance of less activated components, based on the estimated element distribution factors in the extraction and re-extraction processes, and computations, it was shown that the alloy components may be purified from the activation products, using this technology, down to an

Airway Clearance Techniques (ACTs)

Medline Plus

Full Text Available ... NACFC Carolyn and C Richard Mattingly Leadership in Mental Health Care Award Mary M. Kontos Award NACFC Reflections ... help your infant or child manage their lung health, watch parents of children with CF and a respiratory therapist talk about the different techniques they use for airway clearance. ... Instagram Email Find a Clinical Trial Help us blaze ...

7 CFR 1927.53 - Costs of title clearance and closing of transactions.

Science.gov (United States)

2010-01-01

... 7 Agriculture 12 2010-01-01 2010-01-01 false Costs of title clearance and closing of transactions... and Loan Closing § 1927.53 Costs of title clearance and closing of transactions. The borrower or the... payment of all costs of title clearance and closing of the transaction and will arrange for payment before...

Experimental Investigation of Factors Influencing Operating Rotor Tip Clearance in Multistage Compressors

Directory of Open Access Journals (Sweden)

Reid A. Berdanier

2015-01-01

Full Text Available An analysis of compressor rotor tip clearance measurements using capacitance probe instrumentation is discussed for a three-stage axial compressor. Thermal variations and centrifugal effects related to rotational speed changes affect clearance heights relative to the assembled configuration. These two primary contributions to measured changes are discussed both independently and in combination. Emphasis is given to tip clearance changes due to changing loading condition and at several compressor operating speeds. Measurements show a tip clearance change approaching 0.1 mm (0.2% rotor span when comparing a near-choke operating condition to a near-stall operating condition for the third stage. Additional consideration is given to environmental contributions such as ambient temperature, for which changes in tip clearance height on the order of 0.05 mm (0.1% rotor span were noted for temperature variations of 15°C. Experimental compressor operating clearances are presented for several temperatures, operating speeds, and loading conditions, and comparisons are drawn between these measured variations and predicted changes under the same conditions.

USING TERRESTRIAL LASER SCANNERS TO CALCULATE AND MAP VERTICAL BRIDGE CLEARANCE

OpenAIRE

C. Zhang; D. Arditi; Z. Chen

2013-01-01

The vertical clearance of a bridge over a highway is important in preventing oversized vehicles from hitting the bridge. The vertical clearance of a bridge is traditionally measured by using surveying equipment such as leveling rods and total stations. Typically, measurements are taken at multiple locations in order to determine the minimum vertical clearance under the bridge. This process is time and labor consuming. Also, these measurements may not be accurate because of the traffi...

Brain-wide pathway for waste clearance captured by contrast-enhanced MRI

OpenAIRE

Iliff, Jeffrey J.; Lee, Hedok; Yu, Mei; Feng, Tian; Logan, Jean; Nedergaard, Maiken; Benveniste, Helene

2013-01-01

The glymphatic system is a recently defined brain-wide paravascular pathway for cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange that facilitates efficient clearance of solutes and waste from the brain. CSF enters the brain along para-arterial channels to exchange with ISF, which is in turn cleared from the brain along para-venous pathways. Because soluble amyloid β clearance depends on glymphatic pathway function, we proposed that failure of this clearance system contributes t...

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

International Nuclear Information System (INIS)

Hackstein, N.; Puille, M.F.; Bak, Benjamin H.; Scharwat, Oliver; Rau, W.S.

2001-01-01

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

A dosing algorithm for metformin based on the relationships between exposure and renal clearance of metformin in patients with varying degrees of kidney function.

Science.gov (United States)

Duong, Janna K; Kroonen, M Y A M; Kumar, S S; Heerspink, H L; Kirkpatrick, C M; Graham, G G; Williams, K M; Day, R O

2017-08-01

The aims of this study were to investigate the relationship between metformin exposure, renal clearance (CL R ), and apparent non-renal clearance of metformin (CL NR /F) in patients with varying degrees of kidney function and to develop dosing recommendations. Plasma and urine samples were collected from three studies consisting of patients with varying degrees of kidney function (creatinine clearance, CL CR ; range, 14-112 mL/min). A population pharmacokinetic model was built (NONMEM) in which the oral availability (F) was fixed to 0.55 with an estimated inter-individual variability (IIV). Simulations were performed to estimate AUC 0-τ , CL R , and CL NR /F. The data (66 patients, 327 observations) were best described by a two-compartment model, and CL CR was a covariate for CL R . Mean CL R was 17 L/h (CV 22%) and mean CL NR /F was 1.6 L/h (69%).The median recovery of metformin in urine was 49% (range 19-75%) over a dosage interval. When CL R increased due to improved renal function, AUC 0-τ decreased proportionally, while CL NR /F did not change with kidney function. Target doses (mg/day) of metformin can be reached using CL CR /3 × 100 to obtain median AUC 0-12 of 18-26 mg/L/h for metformin IR and AUC 0-24 of 38-51 mg/L/h for metformin XR, with C max  kidney function to maintain consistent drug exposure. However, there is still marked IIV and therapeutic drug monitoring of metformin plasma concentrations is recommended.

HIV impairs opsonic phagocytic clearance of pregnancy-associated malaria parasites.

Directory of Open Access Journals (Sweden)

Jessica Keen

2007-05-01

Full Text Available BACKGROUND: Primigravid (PG women are at risk for pregnancy-associated malaria (PAM. Multigravid (MG women acquire protection against PAM; however, HIV infection impairs this protective response. Protection against PAM is associated with the production of IgG specific for variant surface antigens (VSA-PAM expressed by chondroitin sulfate A (CSA-adhering parasitized erythrocytes (PEs. We hypothesized that VSA-PAM-specific IgG confers protection by promoting opsonic phagocytosis of PAM isolates and that HIV infection impairs this response. METHODS AND FINDINGS: We assessed the ability of VSA-PAM-specific IgG to promote opsonic phagocytosis of CSA-adhering PEs and the impact of HIV infection on this process. Opsonic phagocytosis assays were performed using the CSA-adherent parasite line CS2 and human and murine macrophages. CS2 PEs were opsonized with plasma or purified IgG subclasses from HIV-negative or HIV-infected PG and MG Kenyan women or sympatric men. Levels of IgG subclasses specific for VSA-PAM were compared in HIV-negative and HIV-infected women by flow cytometry. Plasma from HIV-negative MG women, but not PG women or men, promoted the opsonic phagocytosis of CSA-binding PEs (p < 0.001. This function depended on VSA-PAM-specific plasma IgG1 and IgG3. HIV-infected MG women had significantly lower plasma opsonizing activity (median phagocytic index 46 [interquartile range (IQR 18-195] versus 251 [IQR 93-397], p = 0.006 and levels of VSA-PAM-specific IgG1 (mean fluorescence intensity [MFI] 13 [IQR 11-20] versus 30 [IQR 23-41], p < 0.001 and IgG3 (MFI 17 [IQR 14-23] versus 28 [IQR 23-37], p < 0.001 than their HIV-negative MG counterparts. CONCLUSIONS: Opsonic phagocytosis may represent a novel correlate of protection against PAM. HIV infection may increase the susceptibility of multigravid women to PAM by impairing this clearance mechanism.

Lung clearance of {sup 99m} Tc- DTPA in systemic lupus erythematous

Energy Technology Data Exchange (ETDEWEB)

Dalcin, P.T.R; Barreto, S.S.M.; Xavier, R.M.; Brenol, J.C.T. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Hospital de Clinicas. Dept. de Medicina Interna; Cunha, R.D.; Marroni, B.J. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Hospital de Clinicas. Servico de Medicina Nuclear]. E-mail: rxavier@hcpa.ufrgs.br

2002-06-01

The early demonstration of lung involvement in systemic lupus erythematosus (SLE) patients is a difficult but important task. In the present study we attempted to identify abnormalities in pulmonary clearance of 99 mTc-DTPA in SLE, correlating their clearance data with clinical findings and disease activity. Forty-six consecutive SLE patients with and without active disease (LACC score) and 30 normal volunteers were studied. All subjects were submitted to pulmonary scintigraphy with 99 mTc-DTPA to evaluate the pulmonary clearance, and to a chest X-ray, and SLE patients were submitted to tests of disease activity, spirometry, arterial blood gases and tests to assess acute-phase proteins. Pulmonary clearance was faster in SLE patients with active disease when compared to normal controls [half-life of 67.04 min (51.52-82.55 min) in active SLE versus 85.87 min (78.85-92.87 min) in controls, P<0.05] and there was a higher frequency of abnormal clearance rates in patients with active disease (11 of 26 patients, 42.3%) when compared with SLE patients without disease activity (2 of 20 patients, 10%) (P = 0.04). A significant correlation was observed between the clearance rates and cough (P<0.05), but not between the clearance rates and dyspnoea symptoms or radiological findings, duration of SLE disease, antinuclear antibody titers and patterns, C-reactive protein or anti-double stranded DNA antibodies. We conclude that the pulmonary clearance of 99 m Tc-DTPA is increased in SLE patients with active disease. (author)

Comparison of arterial intimal clearances of LDL from diabetic and nondiabetic cholesterol-fed rabbits. Differences in intimal clearance explained by size differences

International Nuclear Information System (INIS)

Nordestgaard, B.G.; Zilversmit, D.B.

1989-01-01

Arterial intimal clearances of low density lipoproteins (LDL) from diabetic cholesterol-fed rabbits (D-LDL) and LDL from nondiabetic cholesterol-fed rabbits (N-LDL) were compared. In six experiments, D-LDL and N-LDL were isolated from a diabetic and a nondiabetic rabbit, were iodinated with 125I and 131I, respectively, were mixed, and were reinjected into the same two rabbits as well as into a normal rabbit. Fractional catabolic rates for D-LDL and N-LDL in normal rabbits were 0.065 and 0.074 h-1 (p less than 0.05), respectively. For five of the six pairs of LDL, the D-LDL was smaller than N-LDL as determined by gel filtration. The arterial permeability to N-LDL, when normalized for differences in arterial cholesterol content, did not appear to differ between diabetic and nondiabetic rabbits. The relative arterial intimal clearance (D-LDL/N-LDL) in arteries from diabetic and nondiabetic rabbits was inversely related to the relative molecular weight (D-LDL/N-LDL). For example, when the molecular weight of D-LDL was as low as 60% of that of N-LDL (i.e., the diameter of D-LDL was reduced 16%), the intimal clearance of D-LDL was 40% larger than that of N-LDL. When, on the other hand, molecular weights and diameters of the two LDL were similar, the intimal clearance was also quite similar. These results suggest that arterial intimal clearance of LDL from diabetic and nondiabetic cholesterol-fed rabbits is comparable unless the two types of LDL have a different size

Clearance of the cervical spine in clinically unevaluable trauma patients.

Science.gov (United States)

Halpern, Casey H; Milby, Andrew H; Guo, Wensheng; Schuster, James M; Gracias, Vicente H; Stein, Sherman C

2010-08-15

Meta-analytic costeffectiveness analysis. Our goal was to compare the results of different management strategies for trauma patients in whom the cervical spine was not clinically evaluable due to impaired consciousness, endotracheal intubation, or painful distracting injuries. We performed a structured literature review related to cervical spine trauma, radiographic clearance techniques (plain radiography, flexion/extension, CT, and MRI), and complications associated with semirigid collar use. Meta-analytic techniques were used to pool data from multiple sources to calculate pooled mean estimates of sensitivities and specificities of imaging techniques for cervical spinal clearance, rates of complications from various clearance strategies and from empirical use of semirigid collars. A decision analysis model was used to compare outcomes and costs among these strategies. Slightly more than 7.5% of patients who are clinically unevaluable have cervical spine injuries, and 42% of these injuries are associated with spinal instability. Sensitivity of plain radiography or fluoroscopy for spinal clearance was 57% (95% CI: 57%-60%). Sensitivities for CT and MRI alone were 83% (82%-84%) and 87% (84%-89%), respectively. Complications associated with collar use ranged from 1.3% (2 days) to 7.1% (10 days) but were usually minor and short-lived. Quadriplegia resulting from spinal instability missed by a clearance test had enormous impacts on longevity, quality of life, and costs. These impacts overshadowed the effects of prolonged collar application, even when the incidence of quadriplegia was extremely low. As currently used, neuroimaging studies for cervical spinal clearance in clinically unevaluable patients are not cost-effective compared with empirical immobilization in a semirigid collar.

Clearance of slightly radioactive material from radiological control in Germany

International Nuclear Information System (INIS)

Thierfeldt, S.

1995-01-01

Clearance from radiological control of slightly radioactive material arising from operation or decommissioning of nuclear installations has been practiced in Germany for nearly two decades. Meanwhile, for the clearance of metal generally approved and applicable recommendations for clearance levels have been issued. For other materials like building waste, case-by-case decisions are made by the state licensing authorities. Efforts to implement consistent sets of clearance levels for all kinds of material are under way. As several decommissioning projects will soon generate large amounts of materials from dismantling, a solution needs to be reached soon. The legal framework in Germany governing the use of atomic energy consists of the Atomic Energy Act and several ordinances. Rules and guidelines including the recommendations of the German Commission for Radiation Protection (SSK) exist on a lower level and are not legally binding. Several generic studies for the derivation of clearance levels for metals and building debris with alpha, beta, and gamma contamination have been performed on behalf of the Federal Ministry for Environment, Nature Conservation and Nuclear Safety, which oriented themselves on an individual dose of 10 microSv/a in agreement with IAEA recommendations. Stochastic models have been used for establishing the connection between specific activity of the material to be released and the resulting individual doses, with significant advantages over deterministic scenarios. In the future, for new SSK recommendations or an ordinance on clearance, the increase of masses from demolition of installations, higher recycling rates in the conventional sector and harmonization with international regulations and standards have to be taken into account

Mucociliary clearance, airway inflammation and nasal symptoms in urban motorcyclists

Directory of Open Access Journals (Sweden)

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.

Formation, clearance, deposition, pathogenicity, and identification of biopharmaceutical-related immune complexes: review and case studies.

Science.gov (United States)

Rojko, Jennifer L; Evans, Mark G; Price, Shari A; Han, Bora; Waine, Gary; DeWitte, Mark; Haynes, Jill; Freimark, Bruce; Martin, Pauline; Raymond, James T; Evering, Winston; Rebelatto, Marlon C; Schenck, Emanuel; Horvath, Christopher

2014-06-01

Vascular inflammation, infusion reactions, glomerulopathies, and other potentially adverse effects may be observed in laboratory animals, including monkeys, on toxicity studies of therapeutic monoclonal antibodies and recombinant human protein drugs. Histopathologic and immunohistochemical (IHC) evaluation suggests these effects may be mediated by deposition of immune complexes (ICs) containing the drug, endogenous immunoglobulin, and/or complement components in the affected tissues. ICs may be observed in glomerulus, blood vessels, synovium, lung, liver, skin, eye, choroid plexus, or other tissues or bound to neutrophils, monocytes/macrophages, or platelets. IC deposition may activate complement, kinin, and/or coagulation/fibrinolytic pathways and result in a systemic proinflammatory response. IC clearance is biphasic in humans and monkeys (first from plasma to liver and/or spleen, second from liver or spleen). IC deposition/clearance is affected by IC composition, immunomodulation, and/or complement activation. Case studies are presented from toxicity study monkeys or rats and indicate IHC-IC deposition patterns similar to those predicted by experimental studies of IC-mediated reactions to heterologous protein administration to monkeys and other species. The IHC-staining patterns are consistent with findings associated with generalized and localized IC-associated pathology in humans. However, manifestations of immunogenicity in preclinical species are generally not considered predictive to humans. © 2014 by The Author(s).

Clearance of building structures for conventional non-nuclear reuse

International Nuclear Information System (INIS)

Buss, K.; Boehringer, S.

1998-01-01

At the example of a fuel assembly plant the strategy of control measurements on building surfaces, which shall be conventionally reused after their clearance, is regarded. Based on the given clearance levels the used measuring methods, especially with regard of possibly covered or intruded uranium contamination, are shown. The possibility of using the in-situ-γ-spectroscopy is discussed. (orig.) [de

CO2 clearance by membrane lungs.

Science.gov (United States)

Sun, Liqun; Kaesler, Andreas; Fernando, Piyumindri; Thompson, Alex J; Toomasian, John M; Bartlett, Robert H

2018-05-01

Commercial membrane lungs are designed to transfer a specific amount of oxygen per unit of venous blood flow. Membrane lungs are much more efficient at removing CO 2 than adding oxygen, but the range of CO 2 transfer is rarely reported. Commercial membrane lungs were studied with the goal of evaluating CO 2 removal capacity. CO 2 removal was measured in 4 commercial membrane lungs under standardized conditions. CO 2 clearance can be greater than 4 times that of oxygen at a given blood flow when the gas to blood flow ratio is elevated to 4:1 or 8:1. The CO 2 clearance was less dependent on surface area and configuration than oxygen transfer. Any ECMO system can be used for selective CO 2 removal.

Plasma catecholamine level and portal venous pressure as guides to prognosis in patients with cirrhosis

DEFF Research Database (Denmark)

Tage-Jensen, U; Henriksen, Jens Henrik; Christensen, E

1988-01-01

clinical and biochemical variables and survival. Forty-seven (58%) of the patients died during the follow-up period. Univariate analysis showed that plasma noradrenaline and adrenaline concentrations, portal pressure, indocyanine green clearance, serum sodium, bilirubin, and albumin concentrations......, and the presence of ascites or cardiovascular disease were of significant prognostic value. In a multivariate analysis (Cox regression model), plasma noradrenaline concentration, portal pressure, serum bilirubin concentration, and the presence of ascites and cardiovascular disease remained significant independent...

Kidney Function and Plasma Copeptin Levels in Healthy Kidney Donors and Autosomal Dominant Polycystic Kidney Disease Patients

NARCIS (Netherlands)

Zittema, Debbie; van den Berg, Else; Meijer, Esther; Boertien, Wendy E.; Muller Kobold, Anneke C.; Franssen, Casper F. M.; de Jong, Paul E.; Bakker, Stephan J. L.; Navis, Gerjan; Gansevoort, Ron T.

Background and objectives Plasma copeptin, a marker of arginine vasopressin, is elevated in patients with autosomal dominant polycystic kidney disease and predicts disease progression. It is unknown whether elevated copeptin levels result from decreased kidney clearance or as compensation for

Dynamic analysis of cross shaft type universal joint with clearance

International Nuclear Information System (INIS)

Lu, Jian Wei; Wang, Gong Cheng; Chen, Hao; Vakakis, Alexander F.; Bergman, Lawrence A.

2013-01-01

Cross shaft type universal joint is widely used in ground vehicles to transfer torque between two intersecting axes, and its transmission feature can make a great contribution to NVH performance of the vehicle. We looked at the assembling clearance at cross shaft neck, and presented a dynamic model of cross shaft type universal joint with clearance at cross shaft neck. Two-state model is applied to describe the contact force between the cross shaft and driving joint fork based on Hertz theorem, and lumped mass method is applied to build up the dynamic model of the universal joint. Based on this model, numerical analysis is carried out to discuss the transmission feature of the universal joint with clearance at cross shaft neck, and the influence of clearance on the dynamic behavior of the system is evaluated with numerical results based on time history, power spectrum, and phase portrait. The method and conclusions presented are helpful to improvement of the transmission feature of cross shaft type universal joint.

Relationships between Endogenous Plasma Biomarkers of Constitutive Cytochrome P450 3A Activity and Single-Time-Point Oral Midazolam Microdose Phenotype in Healthy Subjects.

Science.gov (United States)

Woolsey, Sarah J; Beaton, Melanie D; Choi, Yun-Hee; Dresser, George K; Gryn, Steven E; Kim, Richard B; Tirona, Rommel G

2016-04-01

Due to high basal interindividual variation in cytochrome P450 3A (CYP3A) activity and susceptibility to drug interactions, there has been interest in the application of efficient probe drug phenotyping strategies, as well as endogenous biomarkers for assessment of in vivo CYP3A activity. The biomarkers 4β-hydroxycholesterol (4βHC) and 6β-hydroxycortisol (6βHCL) are sensitive to CYP3A induction and inhibition. However, their utility for the assessment of constitutive CYP3A activity remains uncertain. We investigated whether endogenous plasma biomarkers (4βHC and 6βHCL) are associated with basal CYP3A metabolic activity in healthy subjects assessed by a convenient single-time-point oral midazolam (MDZ) phenotyping strategy. Plasma 4βHC and 6βHCL metabolic ratios (MRs) were analysed in 51 healthy adult participants. CYP3A activity was determined after administration of an oral MDZ microdose (100 μg). Simple linear and multiple linear regression analyses were performed to assess relationships between MDZ oral clearance, biomarkers and subject covariates. Among study subjects, basal MDZ oral clearance, 4βHC and 6βHCL MRs ranged 6.5-, 10- and 13-fold, respectively. Participant age and alcohol consumption were negatively associated with MDZ oral clearance (p = 0.03 and p = 0.045, respectively), while weight and female sex were associated with lower plasma 4βHC MR (p = 0.0003 and p = 0.032, respectively). Neither 4βHC nor 6βHCL MRs were associated with MDZ oral clearance. Plasma 4βHC and 6βHCL MRs do not relate to MDZ single-time-point metabolic phenotype in the assessment of constitutive CYP3A activity among healthy individuals. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

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

DEFF Research Database (Denmark)

Vissing, J; Ohkuwa, T; Ploug, Thorkil

1988-01-01

with nonimmobilized control rats (red gastrocnemius 0.46 +/- 0.02 vs. 0.99 +/- 0.08 and soleus 1.10 +/- 0.30 vs. 3.97 +/- 0.54 ml.min-1.100 g-1, P less than 0.005). During running (18 m/min), glucose clearance did not differ between muscles in previously immobilized and control rats. Insulin levels were always......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...

Exclusion, exemption, clearance European Union approach

International Nuclear Information System (INIS)

Janssens, A.

1997-01-01

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

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

International Nuclear Information System (INIS)

Holland, B.

1997-01-01

ANSTO's radiopharmaceutical production laboratories generate 25 m 3 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 12m 3 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

Impairment of paravascular clearance pathways in the aging brain.

Science.gov (United States)

Kress, Benjamin T; Iliff, Jeffrey J; Xia, Maosheng; Wang, Minghuan; Wei, Helen S; Zeppenfeld, Douglas; Xie, Lulu; Kang, Hongyi; Xu, Qiwu; Liew, Jason A; Plog, Benjamin A; Ding, Fengfei; Deane, Rashid; Nedergaard, Maiken

2014-12-01

In the brain, protein waste removal is partly performed by paravascular pathways that facilitate convective exchange of water and soluble contents between cerebrospinal fluid (CSF) and interstitial fluid (ISF). Several lines of evidence suggest that bulk flow drainage via the glymphatic system is driven by cerebrovascular pulsation, and is dependent on astroglial water channels that line paravascular CSF pathways. The objective of this study was to evaluate whether the efficiency of CSF-ISF exchange and interstitial solute clearance is impaired in the aging brain. CSF-ISF exchange was evaluated by in vivo and ex vivo fluorescence microscopy and interstitial solute clearance was evaluated by radiotracer clearance assays in young (2-3 months), middle-aged (10-12 months), and old (18-20 months) wild-type mice. The relationship between age-related changes in the expression of the astrocytic water channel aquaporin-4 (AQP4) and changes in glymphatic pathway function was evaluated by immunofluorescence. Advancing age was associated with a dramatic decline in the efficiency of exchange between the subarachnoid CSF and the brain parenchyma. Relative to the young, clearance of intraparenchymally injected amyloid-β was impaired by 40% in the old mice. A 27% reduction in the vessel wall pulsatility of intracortical arterioles and widespread loss of perivascular AQP4 polarization along the penetrating arteries accompanied the decline in CSF-ISF exchange. We propose that impaired glymphatic clearance contributes to cognitive decline among the elderly and may represent a novel therapeutic target for the treatment of neurodegenerative diseases associated with accumulation of misfolded protein aggregates. © 2014 American Neurological Association.

Nuclear security. DOE actions to improve the personnel clearance program

International Nuclear Information System (INIS)

Fultz, Keith O.; Bannerman, Carl J.; Daniel, Beverly A.

1988-11-01

The status of the Department of Energy's (DOE) implementation of recommendations in our two reports on DOE's personnel security clearance program was determined. The recommendations were aimed at improving the timeliness, accuracy, and efficiency of personnel security clearance decisions. Specifically, the objective was to determine and report on steps DOE is taking to implement these recommendations. In summary, it was found that DOE has either initiated action or is studying ways to address all the recommendations, but none of the recommendations have been completely implemented. The effectiveness of the DOE actions will depend, in part, on the adequacy of its internal control system for overseeing and evaluating program operations. DOE's personnel security clearance program is intended to provide reasonable assurance that personnel with access to classified information and materials are trustworthy. The Department requests that the Office of Personnel Management or the Federal Bureau of Investigation collect personal data on each person who requires such access to do his or her job. Based on these background investigations, DOE officials authorize individuals whose personal histories indicate that they are trustworthy to have access to classified information, secured facilities, and controlled materials as needed to perform their jobs. DOE has five types of these authorizations or personnel security clearances and must update information on personnel holding each type at 5-year intervals to confirm their continuing reliability. The five types are based on the types of security interests to which the person needs access, e.g., persons needing nuclear weapons-related data must have a Q clearance, and persons with a top secret clearance can have access to national security data classified as top secret

Hepatic macrophage complement receptor clearance function following injury.

Science.gov (United States)

Cuddy, B G; Loegering, D J; Blumenstock, F A; Shah, D M

1986-03-01

Previous work has demonstrated that in vivo hepatic macrophage complement receptor clearance function is depressed following thermal injury. The present study was carried out to determine if complement receptor function depression is associated with other states of depressed host defense. Hepatic complement receptor clearance function was determined from the hepatic uptake of rat erythrocytes coated with antierythrocyte IgM (EIgM) in rats. Receptor function was determined following cannulation of a carotid artery, laparotomy plus enterotomy, hemorrhagic shock, trauma, thermal injury, acute bacteremia, acute endotoxemia, and injection of erythrocyte stroma, gelatinized lipid emulsion, or colloidal carbon. Hepatic uptake of EIgM was depressed following each of these experimental interventions except arterial cannulation. This effect was shown not to be due to a decrease in hepatic blood flow or depletion of complement and was therefore due to a depression in hepatic macrophage complement receptor clearance function. Thus, impairment of hepatic macrophage complement receptor function is associated with several states of depressed host defense.

Clearance potential of ITER vacuum vessel activated materials

International Nuclear Information System (INIS)

Cepraga, D.G.; Cambi, G.; Frisoni, M.

2002-01-01

To demonstrate fusion's environmental attractiveness over the entire life cycle, a waste analysis is mandatory. The clearance is recommended by IAEA for releasing activated solid materials from regulatory control and for waste management policy. The paper focuses on the approach used to support waste analyses for ITER Generic Site Safety Report. The Material Unconditional Clearance Index of all the materials/zones on the equatorial mid-plane of ITER machine have been evaluated, based on IAEA-TECDOC-855. The Bonami-Nitawl-XSDNRPM sequence of the Scale-4.4a code system (using Vitenea-J library) has been firstly used for radiation transport analyses. Then the Anita-2000 code package is used for the activation calculation. The paper presents also, as an example, an application of the clearance indexes estimation for the ITER vacuum vessel materials. The results of the Anita-2000 have been compared with those obtained using the Fispact-99 activation code. (author)

Phosphate, urea and creatinine clearances: haemodialysis adequacy assessed by weekly monitoring.

Science.gov (United States)

Debowska, Malgorzata; Wojcik-Zaluska, Alicja; Ksiazek, Andrzej; Zaluska, Wojciech; Waniewski, Jacek

2015-01-01

The specific distribution of phosphate and the control mechanisms for its plasma level makes phosphate kinetics during haemodialysis (HD) considerably different from those of urea and creatinine and makes the quantitative evaluation of adequacy of phosphate removal difficult. We propose the application of equivalent continuous clearance (ECC) as a phosphate adequacy parameter and compare it with ECC for creatinine and urea. Three consecutive dialysis sessions were evaluated for 25 patients on maintenance HD. Concentrations of phosphate, urea and creatinine in plasma were measured every 1h during the treatment and 45 min after, and every 30 min in dialysate. ECC was calculated using the removed solute mass assessed in dialysate and weekly solute profile in plasma. Similar calculations were performed also for the midweek dialysis session only. Different versions of the reference concentration for ECC were applied. ECC with peak average reference concentration was 5.4 ± 1.0 for phosphate, 7.0 ± 1.0 for urea and 4.7 ± 1.0 mL/min for creatinine. ECC for urea and creatinine were well correlated in contrast to the correlations of ECC for phosphate versus urea and creatinine. Midweek ECC were higher than weekly ECC, but they were well correlated for urea and creatinine, but only weakly for phosphate. HD adequacy monitoring for phosphate may be performed using ECC, but it is less predictable than similar indices for urea and creatinine. The values of ECC for phosphate are within the range expected for its molecular size compared with those for urea and creatinine. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Clearance from the anterior chamber of RBCs from human diabetics

International Nuclear Information System (INIS)

Williams, G.A.; Hatchell, D.L.; Collier, B.D.; Knobel, J.

1984-01-01

Erythrocytes from diabetic patients manifest decreased deformability and increased adherence. These abnormal membrane properties may diminish the ability of erythrocytes (RBCs) from diabetics to undergo deformation in passage through the trabecular meshwork. Using sodium chromate Cr 51-labeled RBCs from type I diabetic patients with proliferative retinopathy and normal control subjects, we studied RBC clearance from the rabbit anterior chamber. The mean time for 50% clearance (T50) of RBCs from diabetics (76 hours) was significantly longer than that for RBCs from normal subjects (19.5 hours). In this model, RBCs from diabetics have a slower clearance from the anterior chamber than do RBCs from normal subjects

Experimental Study of Unshrouded Impeller Pump Stage Sensitivity to Tip Clearance

Science.gov (United States)

Williams, Robert W.; Zoladz, Thomas; Storey, Anne K.; Skelley, Stephen E.

2002-01-01

This viewgraph presentation provides information on an experiment. Its objective is to experimentally determine unshrouded impeller performance sensitivity to tip clearance. The experiment included: Determining impeller efficiency at scaled operating conditions in water at MSFC's Pump Test Equipment (PTE) Facility; Testing unshrouded impeller at three different tip clearances; Testing each tip clearance configuration at on- and off-design conditions, and collecting unsteady- and steady-state data in each configuration; Determining impeller efficiency directly using drive line torquemeter and pump inlet and exit total pressure measurements.

Scan Manifestations and Blood Clearance Rates in Typhoid Liver

International Nuclear Information System (INIS)

Bahk, Yong Whee; Ahn, Jae Sung; Kim, Soon Hi

1970-01-01

Fourteen patients with typhoid fever studied by scanning and clearance-rate measurements of subcritical dose colloidal radiogold ( 198 Au). Mild to moderate enlargement of the liver and spleen was noted in 78.6 and 64.3 percent of patients, respectively; and splenic and spinal bone-marrow uptake was seen in 78.6 and 57.1 percent of cases, respectively. Typically, these scan changes occurred concomitantly (57.1%) and are considered to represent increased phagocytic activity of the RE cells which is characteristic of typhoid fever. The half clearance-time was significantly shortened during the first 10-day period of the illness indicating an increase in the hepatic blood in the early phase of typhoid infection. Hepatomegaly, splenomegaly and extrahepatic uptakes along with an accelerated (or less a normal) clearance time are characteristic of typhoid fever.

Exaggerated natriuresis and lithium clearance in spontaneously hypertensive rats

DEFF Research Database (Denmark)

Holstein-Rathlou, N H; Kanters, J K; Leyssac, P P

1988-01-01

Since hypertension is associated with changes in the handling of various cations (including sodium and lithium) across the cell membrane, the present study investigated the validity of the lithium clearance method in hypertension by comparing two measures of proximal reabsorption. Thus, fractional...... lithium excretion and transit time (TT)-occlusion time (OT; e-TT/T) were determined successively in the same spontaneously hypertensive rat (SHR, Okamoto strain). The rats were examined both before and after an acute saline load. The results show that the lithium clearance method can be used...... for the determination of proximal reabsorption in SHR. Utilizing the lithium clearance method, the changes in renal sodium handling underlying the exaggerated natriuresis were investigated in unanaesthetized catheterized rats. It was found that the exaggerated natriuresis was associated with an increased output from...

Kinematics Simulation Analysis of Packaging Robot with Joint Clearance

Science.gov (United States)

Zhang, Y. W.; Meng, W. J.; Wang, L. Q.; Cui, G. H.

2018-03-01

Considering the influence of joint clearance on the motion error, repeated positioning accuracy and overall position of the machine, this paper presents simulation analysis of a packaging robot — 2 degrees of freedom(DOF) planar parallel robot based on the characteristics of high precision and fast speed of packaging equipment. The motion constraint equation of the mechanism is established, and the analysis and simulation of the motion error are carried out in the case of turning the revolute clearance. The simulation results show that the size of the joint clearance will affect the movement accuracy and packaging efficiency of the packaging robot. The analysis provides a reference point of view for the packaging equipment design and selection criteria and has a great significance on the packaging industry automation.

Numerical study on tip clearance effect on performance of a centrifugal compressor

International Nuclear Information System (INIS)

Eum, Hark Jin; Kang, Shin Kyoung

2003-01-01

Effect of tip leakage flow on through flow and performance of a centrifugal compressor impeller was numerically studied using CFX-TASCflow. Seven different tip clearances were used to consider the influence of tip clearance on performance. Secondary flow and loss factor were evaluated to understand the loss mechanism inside the impeller due to tip leakage flow. The calculated results were circumferentially averaged along the passage and at the impeller exit for quantitative discussion. Tip clearance effect on performance could be decomposed into inviscid and viscous components using one dimensional equation. The inviscid component is related with the specific work reduction and the viscous component is related with the additional entropy generation. Two components affected performance equally, while efficiency drop was mainly influenced by viscous loss. Performance and efficiency drop due to tip clearance were proportional to the ratio of tip clearance to exit blade height. A simple model suggested in the present study predict performance and efficiency drop quite successfully

Plasma kinetics of an LDL-like nanoemulsion and lipid transfer to HDL in subjects with glucose intolerance

Directory of Open Access Journals (Sweden)

Marina P Bertato

2012-01-01

Full Text Available OBJECTIVE: Glucose intolerance is frequently associated with an altered plasma lipid profile and increased cardiovascular disease risk. Nonetheless, lipid metabolism is scarcely studied in normolipidemic glucose-intolerant patients. The aim of this study was to investigate whether important lipid metabolic parameters, such as the kinetics of LDL free and esterified cholesterol and the transfer of lipids to HDL, are altered in glucose-intolerant patients with normal plasma lipids. METHODS: Fourteen glucose-intolerant patients and 15 control patients were studied; none of the patients had cardiovascular disease manifestations, and they were paired for age, sex, race and co-morbidities. A nanoemulsion resembling a LDL lipid composition (LDE labeled with 14C-cholesteryl ester and ³H-free cholesterol was intravenously injected, and blood samples were collected over a 24-h period to determine the fractional clearance rate of the labels by compartmental analysis. The transfer of free and esterified cholesterol, triglycerides and phospholipids from the LDE to HDL was measured by the incubation of the LDE with plasma and radioactivity counting of the supernatant after chemical precipitation of non-HDL fractions. RESULTS: The levels of LDL, non-HDL and HDL cholesterol, triglycerides, apo A1 and apo B were equal in both groups. The 14C-esterified cholesterol fractional clearance rate was not different between glucose-intolerant and control patients, but the ³H-free-cholesterol fractional clearance rate was greater in glucose-intolerant patients than in control patients. The lipid transfer to HDL was equal in both groups. CONCLUSION: In these glucose-intolerant patients with normal plasma lipids, a faster removal of LDE free cholesterol was the only lipid metabolic alteration detected in our study. This finding suggests that the dissociation of free cholesterol from lipoprotein particles occurs in normolipidemic glucose intolerance and may participate in

Renal clearance of /sup 99m/Tc-methylene-diphosphonate in human beings

Energy Technology Data Exchange (ETDEWEB)

Vattimo, A.

1987-12-01

The renal clearance of /sup 99m/Tc-MDP was measured in 13 patients who had bone scans and compared with the renal clearance of /sup 51/Cr-EDTA. No difference was found between the renal clearance of the two tracers, showing a close correlation (r = 0.98). These data suggest that the /sup 99m/Tc-MDP is excreted by the kidneys by glomerular filtration without tubular secretion.

Frequency and factors effecting non clearance of lower pole renal stones

International Nuclear Information System (INIS)

Ullah, A.; Zubair, M.; Khan, N.; Malik, A.

2015-01-01

Renal stone disease is a major health hazard in Pakistan and extra-corporeal shockwave lithotripsy is one of comprehensive method used to treat these stones. The aim of this study is to determine the frequency of factors affecting the non-clearance of stone fragments of lower pole renal stone after extra corporeal shockwave lithotripsy. The study was done with the objective to determine the frequency the spatial anatomical factors which can influence the non-clearance of lower pole stone fragments after ESWL. Methods: One and nineteen (119) patients with lower pole renal stone less than 10 mm were subjected to maximum 3 sessions of extracorporeal shock wave lithotripsy. KUB radiographs, ultrasonography and intravenous urography were used as investigative tools for lower pole renal calyceal anatomy. X ray KUB and ultrasound were done after a week for clearance. Data was analysed with the help of SPSS version 10.0 and presented in the forms of tables and graphs. Results: There were 77 (64.71%) males and 42 (35.29%) females. Infundibulo-pelvic angle (IPA)>40 degree was present in 93 (78.15%), Infundibular length (IL) <22 mm in 107 (89.92%) and Infundibular width (IW) >4 mm was present in 100 (84.03%) patients. The frequency of stone non clearance was noted in 31 (26.05%). Infundibulo-pelvic angle (IPA)>40 degree (p=0.000), Infundibular length (IL)<22 mm (p=0.001) and Infundibular width (IW)>4 mm (p=0.046) were significant variables affecting stone clearance. Conclusion: The frequency of non-clearance of lower calyx of kidney stone is 26.05%. The clearance of fragments of the lower calyx kidney stones is affected by three spatial anatomical factors, i.e., Infundibulopelvic angle, Infundibular width and infundibular length. (author)

Effects of ethanol on plasma protein shedding in the human stomach

International Nuclear Information System (INIS)

Brassinne, A.

1979-01-01

Plasma protein shedding in the stomach was measured in 23 normal individuals before and after intragastric administration of a 30% solution of ethyl alcohol. Two different methods were used to assess plasma protein shedding. The first technique utilizes [ 131 I] albumin and requires neutralization of the gastric juice. It was used in 12 subjects and failed to demonstrate any increase of plasma protein shedding under the influence of ethanol. The second technique which utilizes [ 51 Cr] chloride was used in 11 subjects. It demonstrated a significant increase of the gastric clearance of plasma protein which reached 2.5 times the control values. The [ 51 Cr] chloride technique does not require prior neutralization of gastric acidity. It is concluded that, in normal man, ethanol administration increases plasma protein shedding in the stomach when it is given in the presence of an acid gastric juice. The effect is not observed when the gastric acidity is neutralized

Delayed clearance of serum HBsAg in compensated cirrhosis B

DEFF Research Database (Denmark)

Fattovich, G; Giustina, G; Sanchez-Tapias, J

1998-01-01

The aim of this study was to evaluate the incidence, prognostic factors and clinical significance of delayed clearance of serum HBsAg in compensated cirrhosis B.......The aim of this study was to evaluate the incidence, prognostic factors and clinical significance of delayed clearance of serum HBsAg in compensated cirrhosis B....

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

Energy Technology Data Exchange (ETDEWEB)

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.

The monocytic lineage specific soluble CD163 is a plasma marker of coronary atherosclerosis

DEFF Research Database (Denmark)

Aristoteli, Lina Panayiota; Møller, Holger Jon; Bailey, Brian

2006-01-01

BACKGROUND: CD163 is a monocyte-macrophage lineage specific scavenger receptor that mediates the uptake and clearance of haptoglobin-haemoglobin complexes, and soluble CD163 (sCD163) is also present in plasma. As atherosclerosis involves infiltration by monocyte-derived macrophages, we investigated...... whether sCD163 may act as a marker of coronary atherosclerosis (CAD). METHODS AND RESULTS: Clinical features were identified and plasma was collected from 147 consecutive patients presenting for coronary angiography. Patients were classified as having CAD+, or being free of CAD- haemodynamically...

Novel sensors to enable closed-loop active clearance control in gas turbine engines

Science.gov (United States)

Geisheimer, Jonathan; Holst, Tom

2014-06-01

Active clearance control within the turbine section of gas turbine engines presents and opportunity within aerospace and industrial applications to improve operating efficiencies and the life of downstream components. Open loop clearance control is currently employed during the development of all new large core aerospace engines; however, the ability to measure the gap between the blades and the case and close down the clearance further presents as opportunity to gain even greater efficiencies. The turbine area is one of the harshest environments for long term placement of a sensor in addition to the extreme accuracy requirements required to enable closed loop clearance control. This paper gives an overview of the challenges of clearance measurements within the turbine as well as discusses the latest developments of a microwave sensor designed for this application.

Does sleep disturbance affect the amyloid clearance mechanisms in Alzheimer's disease?

Science.gov (United States)

Yulug, Burak; Hanoglu, Lutfu; Kilic, Ertugrul

2017-10-01

Sleep is an important factor that plays a key role in Alzheimer's disease pathogenesis. However, it is still unclear whether poor-quality sleep may overlap with sleep disturbances in the underlying dysfunctional mechanisms of amyloid beta (Aβ) clearance metabolism. Here, we aimed to evaluate the current evidence on the role of sleep deprivation in Aβ clearance metabolism. To that end, we discuss possible mechanisms underlying the bidirectional interaction between the sleep deprivation and Aβ clearance pathways. © 2017 The Authors. Psychiatry and Clinical Neurosciences © 2017 Japanese Society of Psychiatry and Neurology.

76 FR 59379 - Proposed Information Collection; Comment Request; Generic Clearance for Research in Development...

Science.gov (United States)

2011-09-26

...-XXXX. Type of Review: Generic Clearance Request. Title: Generic Clearance for Research in Development... information collected through qualitative evaluation methods will inform the disclosure form's design and... Proposed Information Collection; Comment Request; Generic Clearance for Research in Development of...

Spontaneous Clearance of Hepatitis C after Liver and Renal Transplantation

Directory of Open Access Journals (Sweden)

CH Dale

2009-01-01

Full Text Available Spontaneous clearance of hepatitis C virus (HCV is rare in immunocompromised patients, such as those who have undergone organ transplantation. It has been recognized that patients receiving liver transplantation for HCV-related disease have decreased graft and patient survival compared with those transplanted for other etiologies. There is a growing trend toward treating HCV recurrence aggressively after liver transplantation. For other organ transplant recipients with concurrent HCV, treatment is not often an option, given the high rates of graft rejection and loss secondary to interferon and its immunomodulatory effects. Although spontaneous clearance of HCV has been reported in recipients of solitary liver and renal transplants, a common factor arising in these cases has been previous exposure to interferon. To date, no reports of spontaneous clearance of HCV RNA have been reported in a multiorgan transplant recipient. A case of spontaneous clearance of HCV RNA in an immunocompromised patient, within five months of simultaneous liver and kidney retransplantation is described. Importantly, this patient had no previous exposure to interferon.

Derivation methods for clearance levels applied to reactors

International Nuclear Information System (INIS)

Okoshi, Minoru; Seki, Takeo

2001-01-01

In order to support the discussion by the Nuclear Safety Commission, JAERI derived the unconditional clearance levels for concrete and metal arising from the operation and dismantling of nuclear reactors. The clearance levels of 20 radionuclides were derived from 10 μSv/y of individual doses by deterministic approach. In this approach, calculation models were established to assess individual doses resulting from 73 exposure pathways related to disposal and recycle/reuse, and realistic parameter values were selected considering Japanese natural and social conditions. The appropriateness of selected parameter values was confirmed by stochastic analyses. (author)

The influence of body posture on lithium clearance

DEFF Research Database (Denmark)

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

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...... 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....

Scan Manifestations and Blood Clearance Rates in Typhoid Liver

Energy Technology Data Exchange (ETDEWEB)

Bahk, Yong Whee; Ahn, Jae Sung; Kim, Soon Hi [St. Mary' s Hospital, Catholic Medical College, Seoul (Korea, Republic of)

1970-09-15

Fourteen patients with typhoid fever studied by scanning and clearance-rate measurements of subcritical dose colloidal radiogold ({sup 198}Au). Mild to moderate enlargement of the liver and spleen was noted in 78.6 and 64.3 percent of patients, respectively; and splenic and spinal bone-marrow uptake was seen in 78.6 and 57.1 percent of cases, respectively. Typically, these scan changes occurred concomitantly (57.1%) and are considered to represent increased phagocytic activity of the RE cells which is characteristic of typhoid fever. The half clearance-time was significantly shortened during the first 10-day period of the illness indicating an increase in the hepatic blood in the early phase of typhoid infection. Hepatomegaly, splenomegaly and extrahepatic uptakes along with an accelerated (or less a normal) clearance time are characteristic of typhoid fever.

Clearance of labelled creatinine

International Nuclear Information System (INIS)

Eberstadt, P.; Liverant, J.

1982-01-01

Creatinine, extensively used in clinical work to evaluate glomerular filtration rate (G.F.R.) has caused controversy. Using simultaneously on dogs a gamma emitting agent measuring G.F.R., creatinine clearance proved to be higher. Aided by quantitative determinations and compartmental analysis fortunately the respective dilution spaces can be calculated. In the majority of these animals creatinine spaces are larger but in some equal to the ones of inulin

The plasma and cerebrospinal fluid pharmacokinetics of erlotinib and its active metabolite (OSI-420) after intravenous administration of erlotinib in non-human primates.

Science.gov (United States)

Meany, Holly J; Fox, Elizabeth; McCully, Cynthia; Tucker, Chris; Balis, Frank M

2008-08-01

Erlotinib hydrochloride is a small molecule inhibitor of epidermal growth factor receptor (EGFR). EGFR is over-expressed in primary brain tumors and solid tumors that metastasize to the central nervous system. We evaluated the plasma and cerebrospinal fluid (CSF) pharmacokinetics of erlotinib and its active metabolite OSI-420 after an intravenous (IV) dose in a non-human primate model. Erlotinib was administered as a 1 h IV infusion to four adult rhesus monkeys. Serial blood and CSF samples were drawn over 48 h and erlotinib and OSI-420 were quantified with an HPLC/tandem mass spectroscopic assay. Pharmacokinetic parameters were estimated using non-compartmental and compartmental methods. CSF penetration was calculated from the AUC(CSF):AUC(plasma). Erlotinib disappearance from plasma after a short IV infusion was biexponential with a mean terminal half-life of 5.2 h and a mean clearance of 128 ml/min per m(2). OSI-420 exposure (AUC) in plasma was 30% (range 12-59%) of erlotinib, and OSI-420 clearance was more than 5-fold higher than erlotinib. Erlotinib and OSI-420 were detectable in CSF. The CSF penetration (AUC(CSF):AUC(plasma)) of erlotinib and OSI-420 was OSI-420 are measurable in CSF after an IV dose. The drug exposure (AUC) in the CSF is limited relative to total plasma concentrations but is substantial relative the free drug exposure in plasma.

Relationship of end-expiratory pressure, lung volume, and /sup 99m/Tc-DTPA clearance

International Nuclear Information System (INIS)

Cooper, J.A.; van der Zee, H.; Line, B.R.; Malik, A.B.

1987-01-01

We investigated the dose-response effect of positive end-expiratory pressure (PEEP) and increased lung volume on the pulmonary clearance rate of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA). Clearance of lung radioactivity was expressed as percent decrease per minute. Base-line clearance was measured while anesthetized sheep (n = 20) were ventilated with 0 cmH 2 O end-expiratory pressure. Clearance was remeasured during ventilation at 2.5, 5, 10, 15, or 20 cmH 2 O PEEP. Further studies showed stepwise increases in functional residual capacity (FRC) (P less than 0.05) measured at 0, 2.5, 5, 10, 15, and 20 cmH 2 O PEEP. At 2.5 cmH 2 O PEEP, the clearance rate was not different from that at base line (P less than 0.05), although FRC was increased from base line. Clearance rate increased progressively with increasing PEEP at 5, 10, and 15 cmH 2 O (P less than 0.05). Between 15 and 20 cmH 2 O PEEP, clearance rate was again unchanged, despite an increase in FRC. The pulmonary clearance of aerosolized /sup 99m/Tc-DTPA shows a sigmoidal response to increasing FRC and PEEP, having both threshold and maximal effects. This relationship is most consistent with the hypothesis that alveolar epithelial permeability is increased by lung inflation

Foot clearance and variability in mono- and multifocal intraocular lens users during stair navigation.

Science.gov (United States)

Renz, Erik; Hackney, Madeleine; Hall, Courtney

2016-01-01

Intraocular lenses (IOLs) provide distance and near refraction and are becoming the standard for cataract surgery. Multifocal glasses increase variability of toe clearance in older adults navigating stairs and increase fall risk; however, little is known about the biomechanics of stair navigation in individuals with multifocal IOLs. This study compared clearance while ascending and descending stairs in individuals with monofocal versus multifocal IOLs. Eight participants with multifocal IOLs (4 men, 4 women; mean age = 66.5 yr, standard deviation [SD] = 6.26) and fifteen male participants with monofocal IOLs (mean age = 69.9 yr, SD = 6.9) underwent vision and mobility testing. Motion analysis recorded kinematic and custom software-calculated clearances in three-dimensional space. No significant differences were found between groups on minimum clearance or variability. Clearance differed for ascending versus descending stairs: the first step onto the stair had the greatest toe clearance during ascent, whereas the final step to the floor had the greatest heel clearance during descent. This preliminary study indicates that multifocal IOLs have similar biomechanic characteristics to monofocal IOLs. Given that step characteristics are related to fall risk, we can tentatively speculate that multifocal IOLs may carry no additional fall risk.

Low serum hyaluronic acid levels associated with spontaneous HBsAg clearance

NARCIS (Netherlands)

Harkisoen, S.; Arends, J. E.; van den Hoek, A.; van Erpecum, K. J.; Boland, G. J.; Hoepelman, A. I. M.

2015-01-01

Purpose The pathophysiological underlying mechanism of spontaneous HBsAg clearance in hepatitis B virus (HBV) infected patients is largely unknown. However, serum hyaluronic acid (sHA) plays a role in liver fibrosis progression and reversely could serve as a potential biomarker for HBsAg clearance.

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

International Nuclear Information System (INIS)

Faerber, D.; Czempiel, H.; Muehle, P.; Schick, F.; Wenzl, H.; Technische Univ. Muenchen; Technische Univ. Muenchen

1979-01-01

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 131 J-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.) [de

Scan Manifestation and Trace-Dose Radiogold Clearance Rates in Obstructive Jaundice

International Nuclear Information System (INIS)

Kim, Dong Jip; Bahk, Yong Whee; Shinn, Kyung Sub

1969-01-01

The present study has been undertaken to analyze scan manifestation in obstructive jaundice. Scan changes were correlated with the duration of jaundice. In addition, clearance rates of trace dose of colloidal radiogold were assessed in each case. The materials were consisted of 19 cases with surgically and/or histopathologically verified obstructive jaundice from various causes including common duct stone, empyema of the gall bladder and carcinoma of the pancreas head etc. Blood clearance rates of colloidal 198 Au were determined after the injection of 8 uCi by simple geometrical drawing of recorded strip charts. Scan was performed following additional injection of the sam radiogold. In 16 out of 19 cases, the scan rather typical 'arborifrom' mottlings around the porta hepatis. The intensity and appearance of such mottlings on the scan was related with the duration of jaundice and level of serum bilirubin and alkaline phosphatase. The blood clearance rates remained to be within normal range in 74 percent of the patients. In the remaining 26 percent, clearance rate ranged between 4.1 and 6 minutes. It is concluded that the association of 'arboriform' mottlings and normal or mildly delayed clearance rates in the patients with jaundice is characteristic of obstructive change in the biliary system.

Scan Manifestation and Trace-Dose Radiogold Clearance Rates in Obstructive Jaundice

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Jip; Bahk, Yong Whee; Shinn, Kyung Sub [Catholic University College of Medicine, Seoul (Korea, Republic of)

1969-09-15

The present study has been undertaken to analyze scan manifestation in obstructive jaundice. Scan changes were correlated with the duration of jaundice. In addition, clearance rates of trace dose of colloidal radiogold were assessed in each case. The materials were consisted of 19 cases with surgically and/or histopathologically verified obstructive jaundice from various causes including common duct stone, empyema of the gall bladder and carcinoma of the pancreas head etc. Blood clearance rates of colloidal {sup 198}Au were determined after the injection of 8 uCi by simple geometrical drawing of recorded strip charts. Scan was performed following additional injection of the sam radiogold. In 16 out of 19 cases, the scan rather typical 'arborifrom' mottlings around the porta hepatis. The intensity and appearance of such mottlings on the scan was related with the duration of jaundice and level of serum bilirubin and alkaline phosphatase. The blood clearance rates remained to be within normal range in 74 percent of the patients. In the remaining 26 percent, clearance rate ranged between 4.1 and 6 minutes. It is concluded that the association of 'arboriform' mottlings and normal or mildly delayed clearance rates in the patients with jaundice is characteristic of obstructive change in the biliary system.

20 CFR 653.501 - Requirements for accepting and processing clearance orders.

Science.gov (United States)

2010-04-01

... the job order. (i) No agricultural or food processing order shall be included in job bank listings... clearance any job order seeking workers to perform agricultural or food processing work before reviewing it... order seeking workers to perform agricultural or food processing work into intrastate clearance unless...

10 CFR 95.21 - Withdrawal of requests for facility security clearance.

Science.gov (United States)

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Withdrawal of requests for facility security clearance. 95.21 Section 95.21 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) FACILITY SECURITY CLEARANCE AND SAFEGUARDING OF NATIONAL SECURITY INFORMATION AND RESTRICTED DATA Physical Security § 95.21 Withdrawal of...

Clearance of insoluble dust from the lower respiratory tract

Energy Technology Data Exchange (ETDEWEB)

Morrow, P E; Gibb, F R; Johnson, L

1964-01-01

Clearance of tagged heavy metal aerosols (Fe, Hg, Mn, Ba, and U) in female beagles by in vivo counting was assessed. Fecal excretion paralleled lower respiratory tract clearance of Fe. No Fe was found in blood, indicating its biological insolubility. Ultrafiltration tests (an indication of biological solubility) ranked the heavy metals as: Hg, Mn, Fe, and U in order of decreasing solubility. The solubility ratios were remarkably similar to the ratios of inverse biological half-times.

[Relation between dose, plasma concentration and therapeutic effect of theophylline in children with sleep apnea].

Science.gov (United States)

Rodríguez-Palomares, C; Ugartechea, J C; Palma-Aguirre, J A; Juárez-Olguín, H; Calderón-Mandujano, B

1989-12-01

The plasma concentration of theophylline was determined in twelve children with infantile sleep apnea (average age 48.5 days). The purpose of the study was to correlate concentrations with the dosages given, the therapeutic response and any adverse effects which could arise. In addition, other pharmacokinetic values were found, half-life (t 1/2) and clearance concentrations (Clss). The oral maintenance dose used was 4 mg/kg/24 h. The serum concentration of theophylline was determined by a homogeneous immunoassay enzyme technique (EMIT). A bad correlation was found (r = 0.45) between the oral dosage given and the plasma concentrations found. This was probably due to variations in the clearance of the drug. Yet, plasma concentrations fell between 3.0 and 12.6 micrograms/mL, enough to satisfactorily control apneic episodes in all the children included in the study without undesirable side-effects. Only one patient had some trouble in falling asleep and showed signs of irritability. The half-life was 13.30 +/- 7.46 hours and Clss was 36.64 +/- 12.98 mL/h/kg. In general, our results correlate with those reported in the literature. The accuracy of the pharmacokinetic parameters with two samples is reliable, therefore avoiding the use of multiple sampling in this group of children.

Dependence of 'CT clearance' on dosage and time

International Nuclear Information System (INIS)

Kaltenborn, H.A.; Klose, K.J.; Dexheimer, C.; Steinijans, V.

1989-01-01

The contrast medium dose used in CT renal function analysis corresponds to about 1 ml/kg body weight at a measurement interval of 5 or 10 minutes. In the present study the dependence of 'CT clearance' on dosage and time was examined in 12 healthy subjects. The amount of clearance was directly proportional to the employed contrast medium dose and to the length of the measurement interval. On account of the superior signal-to-noise ratio, the higher dose (1 ml/kg body weight) will continue to be prefered in future. The measurement interval can be limited to 10 minutes. (orig.) [de

Pulmonary epithelial clearance of 99mTc-DTPA after thrombin-induced pulmonary microembolism

International Nuclear Information System (INIS)

Cooper, J.A.; Feustel, P.J.; Line, B.R.; Malik, A.B.

1986-01-01

We investigated the effect of thrombin-induced pulmonary microembolism on the pulmonary clearance rate of aerosolized 99mTc diethylenetriamine pentaacetic acid (99mTc-DTPA) in awake, chronically prepared sheep. Chest activity was recorded after administration of a 0.44 micron aerosol of 99mTc-DTPA. Decay-corrected data were fit to an exponential and expressed as percent decrease per min (%/min). Sheep were given alpha-thrombin intravenously (80 U/kg for 10 min) 60 min after the aerosol administration. The clearance rate prior to alpha-thrombin was 0.35 +/- 0.05 %/min (mean +/- SEM). During alpha-thrombin administration, the clearance rate increased to 5.84 +/- 0.70 %/min (p less than 0.001 from baseline), but returned to 0.41 +/- 0.06 %/min within 30 min after the end of the thrombin infusion. The increased clearance rate during alpha-thrombin administration was not due to increased lung volume since alpha-thrombin did not change functional residual capacity. Moreover, the clearance rate was unchanged during gamma-thrombin administration, which does not induce coagulation, or during alpha-thrombin challenge in defibrinogenated animals. alpha-thrombin administration in neutrophil-depleted sheep caused a transient increase in DTPA clearance similar to that in control sheep, suggesting that the increase occurred independently of neutrophils. The results indicate that alpha-thrombin causes a large, transient increase in 99mTc-DTPA clearance, which may be the result of increased epithelial permeability. This response is dependent on the activation of intravascular coagulation

Lactate clearance cut off for early mortality prediction in adult sepsis and septic shock patients

Science.gov (United States)

Sinto, R.; Widodo, D.; Pohan, H. T.

2018-03-01

Previous lactate clearance cut off for early mortality prediction in sepsis and septic shock patient was determined by consensus from small sample size-study. We investigated the best lactate clearance cut off and its ability to predict early mortality in sepsis and septic shock patients. This cohort study was conducted in Intensive Care Unit of CiptoMangunkusumo Hospital in 2013. Patients’ lactate clearance and eight other resuscitationendpoints were recorded, and theoutcome was observed during the first 120 hours. The clearance cut off was determined using receiver operating characteristic (ROC) analysis, and its ability was investigated with Cox’s proportional hazard regression analysis using other resuscitation endpoints as confounders. Total of 268 subjects was included, of whom 70 (26.11%) subjects died within the first 120 hours. The area under ROC of lactate clearance to predict early mortality was 0.78 (95% % confidence interval [CI] 0.71-0.84) with best cut off was <7.5% (sensitivity and specificity 88.99% and 81.4% respectively). Compared with group achieving lactate clearance target, group not achieving lactate clearance target had to increase early mortality risk (adjusted hazard ratio 13.42; 95%CI 7.19-25.07). In conclusion, the best lactate clearance cut off as anearly mortality predictor in sepsis and septic shock patients is 7.5%.

Numerical Investigation of Pressure Fluctuation Characteristics in a Centrifugal Pump with Variable Axial Clearance

Directory of Open Access Journals (Sweden)

Lei Cao

2016-01-01

Full Text Available Clearance flows in the sidewall gaps of centrifugal pumps are unsteady as well as main flows in the volute casing and impeller, which may cause vibration and noise, and the corresponding pressure fluctuations are related to the axial clearance size. In this paper, unsteady numerical simulations were conducted to predict the unsteady flows within the entire flow passage of a centrifugal pump operating in the design condition. Pressure fluctuation characteristics in the volute casing, impeller, and sidewall gaps were investigated with three axial clearance sizes. Results show that an axial clearance variation affects the pressure fluctuation characteristics in each flow domain by different degree. The greatest pressure fluctuation occurs at the blade pressure surface and is almost not influenced by the axial clearance variation which has a certainly effect on the pressure fluctuation characteristics around the tongue. The maximum pressure fluctuation amplitude in the sidewall gaps is larger than that in the volute casing, and different spectrum characteristics show up in the three models due to the interaction between the clearance flow and the main flow as well as the rotor-stator interaction. Therefore, clearance flow should be taken into consideration in the hydraulic design of centrifugal pumps.

Bile Acid Sequestration Reduces Plasma Glucose Levels in db/db Mice by Increasing Its Metabolic Clearance Rate

NARCIS (Netherlands)

Meissner, M.; Herrema, H.J.; Dijk, van Th.; Gerding, A.; Havinga, R.; Boer, T.; Müller, M.R.; Reijngoud, D.J.; Groen, A.K.; Kuipers, F.

2011-01-01

Aims/Hypothesis: Bile acid sequestrants (BAS) reduce plasma glucose levels in type II diabetics and in murine models of diabetes but the mechanism herein is unknown. We hypothesized that sequestrant-induced changes in hepatic glucose metabolism would underlie reduced plasma glucose levels.

Clearance, a powerful tool in optimizing the volume of radioactive wastes

International Nuclear Information System (INIS)

Blommaert, W.; Teunckens, L.

1997-01-01

In the framework its activities in decommissioning nuclear installations, Belgoprocess applies the clearance practice in optimizing the volume of radioactive wastes. The applied clearance methodology is discussed with special emphasis to different types of materials and to the associated measurements. Four practical cases are elaborated, dealing with the decommissioning and decontamination of two small buildings up to green field conditions, the unconditional release of large quantities of slightly contaminated active carbon, the melting and clearance of stainless steel fuel racks and of aluminium heat exchangers. The attention is drawn on practical problems associated with sampling and measurement strategies, in relation to the proposed low limits for unconditional release. (author)

A review and comparison of international exemption and clearance levels

International Nuclear Information System (INIS)

Cooper, J.R.; Mobbs, S.F.

1997-01-01

The publication of new European Basic Safety Standards by the European Commission and of new International Basic Safety Standards by the IAEA together with other international agencies, has led to increased interest in the application of the concepts of exemption and clearance. This paper discusses the derivation of radionuclide-specific exemption and clearance values for application in various areas of the regulation of radioactive materials. (author)

Metabolic clearance and blood production rates of estradiol in hyperthyroidism.

Science.gov (United States)

Ridgway, E C; Longcope, C; Maloof, F

1975-09-01

The metabolic clearance rate of 17beta-estradiol (MCR2), the plasma levels of 17beta-estradiol (E2)1, sex-steroid binding globulin (SSBG), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured in 10 hyperthyroid subjects (7 men and 3 women). The blood production rate of 17beta-estradiol (PB2) was calculated for all subjects. Nine of the 10 hyperthyroid subjects had a decreased MCR2 which returned towards normal in 5 of the 6 subjects restudied following therapy. In all 10 subjects the levels of SSBG were increased when they were hyperthyroid and returned toward normal with therapy. It is concluded that the decrease in MCR2 is largely due to the increased binding of 17beta-estradiol to SSBG. In 7 of the 10 hyperthyroid the plasma E2 concentrations were normal whereas 3 had slightly elevated levels. In 8 of the 10 hyperthyroid the PB2 was within the normal range. Only 2 hyperthyroid subjects had slightly elevated PB2. In the 6 subjects who were restudied after therapy, there was no consistent change in PB2 which remained in the normal range in all cases. It is concluded that the MCR2 is decreased in most subjects with hyperthyroidism in association with an increase of SSBG. Despite this change in MCR2 there is no significant change in PB2. The increase in SSBG levels in hyperthyroidism appears to be a direct effect of the elevation of thyroid hormone activity and is not mediated through estrogen.

Clearance measurements on activated parts of accelerators by combined methods; Verfahrenskombinierte Freigabemessung aktivierter Beschleunigerteile

Energy Technology Data Exchange (ETDEWEB)

Jansen, S.; Friedemann, S. [VKTA, Dresden (Germany); Enghardt, W. [Technische Univ. Dresden (Germany). OncoRay

2016-07-01

The process of clearance of radioactive materials according to paragraph 29 StrlSchV contents the comparison of activity to mass and surface of the material. To avoid a borderless assessment of activity of activation it is often necessary to use combined measurement methods: For clearance of collimators of a medical proton accelerator (energy range up to 200 MeV) it needs to know the nuclide composition. The energetical and geometrical calibration was fixed by experiments. The clearance based on measurements of activity distribution, gammaspectroscopy verification of nuclide composition and gamma-counting detectors. Parts of medical electron-accelerators achieved its clearance by combination of abovementioned methods and in-situ-gammaspectroscopy. Activated und contaminated lead stones achieved its clearance by measurements of fluence, laboratory evaluation of samples, in-situ-gammaspectroscopy and wipe tests.

HPLC assay for ethiofos in plasma: Application to pharmacokinetics in the beagle dog

International Nuclear Information System (INIS)

Swynnerton, N.F.; Mangold, D.J.; Ludden, T.M.

1985-01-01

An HPLC assay for ethiofos [S-2-(3-amino-propylamino)ethyl phosphorothioate, WR 2727] in plasma is presented. Its application to the development of pharmacokinetic parameters following IV administration of the drug to beagle dogs is demonstrated and preliminary pharmacokinetics of four dosings will be presented. Following a dose of 150 mg kg -1 , the plasma concentration versus time profile was best described by a two-compartment pharmacokinetics model. Mean pharmacokinetic parameters were: terminal elimination half-life = 16.0 minutes, volume of central compartment = 129 mL kg -1 , and clearance = 11.0 mL min -1 kg -1

Comparison of gas clearance and radioactive microspheres for pancreatic blood flow measurement

International Nuclear Information System (INIS)

DeMar, A.R.; Graham, L.S.; Lake, R.; Fink, A.S.

1989-01-01

Measurement of pancreatic blood flow (PBF) is technically demanding. Although radiolabeled microspheres are considered the gold standard for PBF assessment, they have practical limitations. In the current study, H 2 and xenon-133 gas clearance techniques were adapted to PBF measurement and compared to radiolabeled microsphere techniques. Simultaneous measurements of PBF were made using either hydrogen or xenon gas washout and radiolabeled microspheres. Measurements were made under basal, vasoconstricted (vasopressin 2U i.v. or nicotine 4 micrograms/kg/h) and stimulated (secretin 125 ng/kg/h or 2 U/kg i.v.) conditions (random order). Mean PBF was 26.9 +/- 5.3, 50.5 +/- 2.3 and 27.6 +/- 5.2 ml/min/100 g basally, 36.9 +/- 8.0, 90.1 +/- 18.9, and 81.7 +/- 14.5 ml/min/100 g in the stimulated state, and 24.2 +/- 7.8, 25.0 +/- 3.5, and 14.9 +/- 7.5 ml/min/100 g in the vasoconstricted state for hydrogen gas clearance, xenon gas clearance, and radiolabeled microspheres, respectively. The H 2 clearance technique resulted in tissue trauma, was complicated by frequent electrode displacement, and correlated poorly (r2 = 0.36, p greater than 0.05) with microsphere values. In contrast, xenon clearance measurement had no apparent effect on the pancreas and correlated well (r2 = 0.83, p less than 0.01) with microsphere data. We conclude that xenon clearance offers an attractive, validated alternative to radiolabeled microspheres for measuring pancreatic blood flow

Long-term clearance from small airways in subjects with ciliary dysfunction

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Hjelte Lena

2006-05-01

Full Text Available Abstract The objective of this study was to investigate if long-term clearance from small airways is dependent on normal ciliary function. Six young adults with primary ciliary dyskinesia (PCD inhaled 111 Indium labelled Teflon particles of 4.2 μm geometric and 6.2 μm aerodynamic diameter with an extremely slow inhalation flow, 0.05 L/s. The inhalation method deposits particles mainly in the small conducting airways. Lung retention was measured immediately after inhalation and at four occasions up to 21 days after inhalation. Results were compared with data from ten healthy controls. For additional comparison three of the PCD subjects also inhaled the test particles with normal inhalation flow, 0.5 L/s, providing a more central deposition. The lung retention at 24 h in % of lung deposition (Ret24 was higher (p 24 with slow inhalation flow was 73.9 ± 1.9 % compared to 68.9 ± 7.5 % with normal inhalation flow in the three PCD subjects exposed twice. During day 7–21 the three PCD subjects exposed twice cleared 9 % with normal flow, probably representing predominantly alveolar clearance, compared to 19 % with slow inhalation flow, probably representing mainly small airway clearance. This study shows that despite ciliary dysfunction, clearance continues in the small airways beyond 24 h. There are apparently additional clearance mechanisms present in the small airways.

APPLICATION OF DSM IN OBSTACLE CLEARANCE SURVEYING OF AERODROME

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X. Qiao

2016-06-01

Full Text Available Compared to the wide use of digital elevation model (DEM, digital surface model (DSM receives less attention because that it is composed by not only terrain surface, but also vegetations and man-made objects which are usually regarded as useless information. Nevertheless, these objects are useful for the identification of obstacles around an aerodrome. The primary objective of the study was to determine the applicability of DSM in obstacle clearance surveying of aerodrome. According to the requirements of obstacle clearance surveying at QT airport, aerial and satellite imagery were used to generate DSM, by means of photogrammetry, which was spatially analyzed with the hypothetical 3D obstacle limitation surfaces (OLS to identify the potential obstacles. Field surveying was then carried out to retrieve the accurate horizontal position and height of the obstacles. The results proved that the application of DSM could make considerable improvement in the efficiency of obstacle clearance surveying of aerodrome.

Dysregulation of Nutrient Sensing and CLEARance in Presenilin Deficiency

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Kavya Reddy

2016-03-01

Full Text Available Attenuated auto-lysosomal system has been associated with Alzheimer disease (AD, yet all underlying molecular mechanisms leading to this impairment are unknown. We show that the amino acid sensing of mechanistic target of rapamycin complex 1 (mTORC1 is dysregulated in cells deficient in presenilin, a protein associated with AD. In these cells, mTORC1 is constitutively tethered to lysosomal membranes, unresponsive to starvation, and inhibitory to TFEB-mediated clearance due to a reduction in Sestrin2 expression. Normalization of Sestrin2 levels through overexpression or elevation of nuclear calcium rescued mTORC1 tethering and initiated clearance. While CLEAR network attenuation in vivo results in buildup of amyloid, phospho-Tau, and neurodegeneration, presenilin-knockout fibroblasts and iPSC-derived AD human neurons fail to effectively initiate autophagy. These results propose an altered mechanism for nutrient sensing in presenilin deficiency and underline an importance of clearance pathways in the onset of AD.

Effects of sustained exercise on pulmonary clearance of aerosolized 99mTc-DTPA

International Nuclear Information System (INIS)

Lorino, A.M.; Meignan, M.; Bouissou, P.; Atlan, G.

1989-01-01

The effects of intensive prolonged exercise on the pulmonary clearance rate of aerosolized 99m Tc-labeled diethylenetriaminepentaacetate ( 99m Tc-DTPA) and pulmonary mechanics were studied in seven healthy nonsmoking volunteers. 99m Tc-DTPA clearance and pulmonary mechanics (lung volumes and compliance) were assessed before and after 75 min of constant-load exercise performed on a treadmill, corresponding to 75% of maximal O 2 uptake. Because both clearance measurements were made in similar conditions of pulmonary blood flow, respiratory rate, and tidal volume, changes in clearance rate can be assumed to represent changes of alveolar epithelial permeability. After exercise, total, apical, and basal clearance were significantly increased (P less than 0.01, 0.05, and 0.05, respectively) and the increases in total clearance and tidal volume observed during exercise were significantly correlated (P less than 0.05). In contrast, no significant change was found in pulmonary mechanics. These results show that prolonged intensive exercise induces an increase in epithelial permeability, which appears to be related to the mechanical effects of sustained increased ventilation. Because no change was evidenced in pulmonary volumes or in lung elasticity, our results suggest that this increase may result from alteration of the intercellular tight junctions rather than from a surfactant deficiency

Higher Midazolam Clearance in Obese Adolescents Compared with Morbidly Obese Adults

NARCIS (Netherlands)

Rongen, van A.; Brill, M.J.E.; Vaughns, J.D.; Välitalo, P.A.J.; Dongen, van E.P.A.; Ramshorst, van B.; Barrett, J.S.; Anker, van den J.N.; Knibbe, C.A.J.

2017-01-01

The clearance of cytochrome P450 (CYP) 3A substrates is reported to be reduced with lower age, inflammation and obesity. As it is unknown what the overall influence is of these factors in the case of obese adolescents vs. morbidly obese adults, we studied covariates influencing the clearance of the

Assessment of effectiveness of Anderson-Hynes operation in patients with unilateral hydronephrosis according to the data of radionuclide renography and clearance-tests

International Nuclear Information System (INIS)

Khripta, F.P.; Kogut, Yu.Ya.

1988-01-01

The function of injured and contralateral kidneys is studied according to the data of radionuclide renography, effective kidney plasma flow and glomerular filtration in 35 patients with unilateral hydronephrosis after the Andersen-Heinz operation. The comparative estimate of the data obtained before and after operation (in different periods) is carried out. The improvement of functions of the hydronephrotic kidney is found both 1-5 years and 0.5 year after the operation. It is shown that radionuclide clearance tests are objective methods of studying remote results of surgical treatment of hydronephrosis. 8 refs

Axial compressor blade design for desensitization of aerodynamic performance and stability to tip clearance

Science.gov (United States)

Erler, Engin

Tip clearance flow is the flow through the clearance between the rotor blade tip and the shroud of a turbomachine, such as compressors and turbines. This flow is driven by the pressure difference across the blade (aerodynamic loading) in the tip region and is a major source of loss in performance and aerodynamic stability in axial compressors of modern aircraft engines. An increase in tip clearance, either temporary due to differential radial expansion between the blade and the shroud during transient operation or permanent due to engine wear or manufacturing tolerances on small blades, increases tip clearance flow and results in higher fuel consumption and higher risk of engine surge. A compressor design that can reduce the sensitivity of its performance and aerodynamic stability to tip clearance increase would have a major impact on short and long-term engine performance and operating envelope. While much research has been carried out on improving nominal compressor performance, little had been done on desensitization to tip clearance increase beyond isolated observations that certain blade designs such as forward chordwise sweep, seem to be less sensitive to tip clearance size increase. The current project aims to identify through a computational study the flow features and associated mechanisms that reduces sensitivity of axial compressor rotors to tip clearance size and propose blade design strategies that can exploit these results. The methodology starts with the design of a reference conventional axial compressor rotor followed by a parametric study with variations of this reference design through modification of the camber line and of the stacking line of blade profiles along the span. It is noted that a simple desensitization method would be to reduce the aerodynamic loading of the blade tip which would reduce the tip clearance flow and its proportional contribution to performance loss. However, with the larger part of the work on the flow done in this

Initial plasma disappearance and tissue uptake of 131I-albumin in normal rabbits

International Nuclear Information System (INIS)

Bent-Hansen, L.

1991-01-01

The simultaneous plasma disappearance curves of 131I-albumin and 125I-fibrinogen were recorded in normal rabbits for 1 hr. Using fibrinogen as a plasma reference, the disappearance curves of albumin were shown to contain two separate phases of efflux: one fast from zero to 10 min. comprising 8% of the total tracer; and one slow appearing in the interval of 10 to 60 min. containing another 9% of the tracer. Total albumin escape was analyzed to yield an initial slope of 0.024 ± 0.004 min-1, corresponding to a wholebody unidirectional albumin clearance (Cl(0)) of 0.090 ± 0.009 ml(min*100 g)-1. The distribution of efflux was assessed by biopsy uptakes using the same tracers in spleen, kidney, heart, lung, liver, intestine, skin, muscle, and brain. The disappearance curve generally reflects a biphasic pattern of uptake in peripheral tissue, predominantly by muscle and lung. The rapid phase has contributions from the fast near equilibration of liver, and intestine and skin are significant codeterminants of the slow phase. Due to their low body masses highly perfused organs such as kidney, spleen, and heart have little influence on the plasma disappearance. In accordance, the Cl(0) determined for the wholebody was higher than initial clearances found in skin (0.053 ml(min*100 g)-1) and muscle (0.054 ml(min*100 g)-1), but much lower than those found in the highly perfused organs. The initial (unidirectional) rates of peripheral albumin transfer demonstrated, ranged from 10 to 30 times higher than estimates of lymphatic return, suggesting that transcapillary albumin exchange is mediated by high-rate bidirectional diffusion. The rapid decrease of net albumin exchange rates suggests a second, highly significant barrier located within the interstitial matrix, which restricts plasma escape and reduces plasma to lymph albumin transport

Characterization and Clearance of m/s Sigyn

International Nuclear Information System (INIS)

Jiselmark, Jonatan; Vreede, Patrick

2016-01-01

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)

Enhancement of Toxic Substances Clearance from Blood Equvalent Solution and Human Whole Blood through High Flux Dialyzer by 1 MHz Ultrasound

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Shiran M. B.

2017-06-01

Full Text Available Background: Hemodialysis is a process of removing waste and excess fluid from blood when kidneys cannot function efficiently. It often involves diverting blood to the filter of the dialysis machin to be cleared of toxic substances. Fouling of pores in dialysis membrane caused by adhesion of plasma protein and other toxins will reduce the efficacy of the filtre. Objective: In This study, the influence of pulsed ultrasound waves on diffusion and the prevention of fouling in the filter membrane were investigated. Material and Methods: Pulsed ultrasound waves with frequency of 1 MHz at an intensity of 1 W/cm2 was applied to the high flux (PES 130 filter. Blood and blood equivalent solutions were passed through the filter in separate experimental setups. The amount of Creatinine, Urea and Inulin cleared from both blood equvalent solution and human whole blood passed through High Flux (PES 130 filter were measured in the presence and absence of ultrasound irradiation. Samples were taken from the outlet of the dialyzer every five minutes and the clearance of each constituent was calculated. Results: Statistical analysis of the blood equvalent solution and whole blood indicated the clearance of Urea and Inulin in the presence of ultrasound increased (p<0.05, while no significant effects were observed for Creatinine. Conclusion: It may be concluded that ultrasound, as a mechanical force, can increase the rate of clearance of some toxins (such as middle and large molecules in the hemodialysis process.

Enhancement of Toxic Substances Clearance from Blood Equvalent Solution and Human Whole Blood through High Flux Dialyzer by 1 MHz Ultrasound

Science.gov (United States)

Shiran, M.B.; Barzegar Marvasti, M.; Shakeri-Zadeh, A.; Shahidi, M.; Tabkhi, N.; Farkhondeh, F.; Kalantar, E.; Asadinejad, A.

2017-01-01

Background: Hemodialysis is a process of removing waste and excess fluid from blood when kidneys cannot function efficiently. It often involves diverting blood to the filter of the dialysis machin to be cleared of toxic substances. Fouling of pores in dialysis membrane caused by adhesion of plasma protein and other toxins will reduce the efficacy of the filtre. Objective: In This study, the influence of pulsed ultrasound waves on diffusion and the prevention of fouling in the filter membrane were investigated. Material and Methods: Pulsed ultrasound waves with frequency of 1 MHz at an intensity of 1 W/cm2 was applied to the high flux (PES 130) filter. Blood and blood equivalent solutions were passed through the filter in separate experimental setups. The amount of Creatinine, Urea and Inulin cleared from both blood equvalent solution and human whole blood passed through High Flux (PES 130) filter were measured in the presence and absence of ultrasound irradiation. Samples were taken from the outlet of the dialyzer every five minutes and the clearance of each constituent was calculated. Results: Statistical analysis of the blood equvalent solution and whole blood indicated the clearance of Urea and Inulin in the presence of ultrasound increased (p<0.05), while no significant effects were observed for Creatinine. Conclusion: It may be concluded that ultrasound, as a mechanical force, can increase the rate of clearance of some toxins (such as middle and large molecules) in the hemodialysis process. PMID:28580332

Clearance of glucoregulatory peptide hormones during haemodialysis and haemodiafiltration in non-diabetic end-stage renal disease patients

DEFF Research Database (Denmark)

Jørgensen, Morten B; Idorn, Thomas; Knop, Filip K

2015-01-01

BACKGROUND: Patients with end-stage renal disease (ESRD) have increased fasting concentrations and disturbed postprandial responses of several glucoregulatory hormones. We aimed to evaluate the impact of high-flux haemodialysis (HD) and high-volume haemodiafiltration (HDF) on fasting and postpran......BACKGROUND: Patients with end-stage renal disease (ESRD) have increased fasting concentrations and disturbed postprandial responses of several glucoregulatory hormones. We aimed to evaluate the impact of high-flux haemodialysis (HD) and high-volume haemodiafiltration (HDF) on fasting...... and postprandial plasma levels of glucoregulatory pancreatic and gut peptide hormones in ESRD patients. METHODS: Ten non-diabetic HD-treated ESRD patients were included to undergo a 3-h standardized liquid mixed meal test 1 h into an HD and an HDF, respectively. On a third, optional, examination day, the meal test...... during HDF and four completed the optional meal test without dialysis. All plasma hormone concentrations declined significantly during the first fasting hour of dialysis with no differences between HD and HDF. Significant clearance of the investigated hormones was observed for both dialysis modalities...

A stochastic approach to the derivation of exemption and clearance levels

International Nuclear Information System (INIS)

Deckert, A.

1997-01-01

Deciding what clearance levels are appropriate for a particular waste stream inherently involves a number of uncertainties. Some of these uncertainties can be quantified using stochastic modeling techniques, which can aid the process of decision making. In this presentation the German approach to dealing with the uncertainties involved in setting clearance levels is addressed. (author)

Increased concentrations of plasma IL-18 in patients with hepatic dysfunction after hepatectomy.

Science.gov (United States)

Shibata, M; Hirota, M; Nozawa, F; Okabe, A; Kurimoto, M; Ogawa, M

2000-10-01

We investigated the dynamic aspects of circulatory IL-18 and other inflammatory cytokines in patients who underwent a hepatectomy. In patients with post-operative hepatic dysfunction, plasma concentrations of these cytokines increased, reflecting severe surgical trauma. IL-6, IL-10 and IFN-gamma increased in the early phase, while IL-18 increased in the later phase after 1 week. Interestingly, the increase in the plasma IL-18 concentration was correlated with that in serum bilirubin levels in hepatectomized patients. Hence, the decrease in the hepatic metabolism of IL-18 may cause the plasma accumulation of IL-18. This mechanism was confirmed using rat experiments. Intravenously administered human IL-18 was excreted into bile. Furthermore, the plasma clearance of human IL-18 was prolonged in bile duct-ligated rats. These results suggest that IL-18 is metabolized in the liver and excreted into bile, and an increase in plasma IL-18 in patients with hepatic dysfunction reflects the decreased metabolism in the liver. Copyright 2000 Academic Press.

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

International Nuclear Information System (INIS)

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

2011-01-01

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.

Traffic Incident Clearance Time and Arrival Time Prediction Based on Hazard Models

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Yang beibei Ji

2014-01-01

Full Text Available Accurate prediction of incident duration is not only important information of Traffic Incident Management System, but also an effective input for travel time prediction. In this paper, the hazard based prediction models are developed for both incident clearance time and arrival time. The data are obtained from the Queensland Department of Transport and Main Roads’ STREAMS Incident Management System (SIMS for one year ending in November 2010. The best fitting distributions are drawn for both clearance and arrival time for 3 types of incident: crash, stationary vehicle, and hazard. The results show that Gamma, Log-logistic, and Weibull are the best fit for crash, stationary vehicle, and hazard incident, respectively. The obvious impact factors are given for crash clearance time and arrival time. The quantitative influences for crash and hazard incident are presented for both clearance and arrival. The model accuracy is analyzed at the end.

Differential effect of T-type voltage-gated calcium channel disruption on renal plasma flow and glomerular filtration rate in vivo

DEFF Research Database (Denmark)

Thuesen, Anne D; Andersen, Henrik; Cardel, Majken

2014-01-01

Voltage-gated calcium channels (Cav) play an essential role in regulation of renal blood flow and GFR. Because T-type Cavs are differentially expressed in pre- and postglomerular vessels it was hypothesized that they impact renal blood flow and GFR differentially. The question was addressed by use...... of two T-type Cav knock-out mice strains. Continuous recordings of blood pressure and heart rate, and para-aminohippurate clearance (renal plasma flow) and inulin clearance (GFR) were performed in conscious, chronically catheterized, wild type and Cav 3.1-/- and Cav 3.2-/- mice. Contractility of afferent...... and efferent arterioles was determined in isolated perfused blood vessels. Efferent arterioles from Cav 3.2-/- mice constricted significantly more in response to a depolarization compared to Wt mice. GFR was increased in Cav 3.2-/- mice with no significant changes in renal plasma flow, heart rate and blood...

Production of plastic scintillation survey meter for clearance verification measurement

International Nuclear Information System (INIS)

Tachibana, Mitsuo; Shiraishi, Kunio; Ishigami, Tsutomu; Tomii, Hiroyuki

2008-03-01

In the Nuclear Science Research Institute, the decommissioning of various nuclear facilities is carried out according to the plan for meeting the midterm goal of the Japan Atomic Energy Agency (JAEA). An increase in the clearance verification measurement of concrete on buildings and the radiation measurement for releasing controlled areas will be expected along with the dismantlement of nuclear facilities in the future. The radiation measurement for releasing controlled areas has been carried out in small-scale nuclear facilities including the JPDR (Japan Power Demonstration Reactor). However, the radiation measurement with an existing measuring device was difficult in effects of radiation from radioactive materials that remains in buried piping. On the other hand, there is no experience that the clearance verification measurement is executed in the JAEA. The generation of a large amount of clearance object will be expected along with the decommissioning of the nuclear facilities in the future. The plastic scintillation survey meter (hereafter, 'PL measuring device') was produced to apply to the clearance verification measurement and the radiation measurement for releasing controlled areas. The basic characteristic test and the actual test were confirmed using the PL measuring device. As a result of these tests, it was found that the evaluation value of radioactivity with the PL measuring device was accuracy equal with the existing measuring device. The PL measuring device has feature of the existing measuring device with a light weight and easy operability. The PL measuring device can correct the gamma ray too. The PL measuring device is effective to the clearance verification measurement of concrete on buildings and the radiation measurement for releasing controlled areas. (author)

[Airway clearance techniques in chronic obstructive pulmonary syndrome : 2011 update].

Science.gov (United States)

Opdekamp, C

2011-09-01

For many years the airway clearance techniques used in chest physical therapy were assimilated with the singular technique of postural drainage, percussions and vibrations. However the side effects and counter indications and the lack of scientific proof regarding this technique have forced reflection and development of other techniques more comfortable and without deleterious effects. If all these techniques show a high efficiency in terms of improved mucociliary clearance, the literature is unanimous on how little effect these techniques have in the short and the long-term with regards to lung function and arterial blood gases. In view of the scientific literature, it is clear that the airway clearance techniques don't have the same recognition concerning their efficiency in all obstructive pulmonary diseases. As the cornerstone in the management of cystic fibrosis, the efficiency of the bronchial hygiene techniques are in general poorly documented in the management of the non-cystic fibrosis bronchiectasis, bronchitis or emphysema. The use of the chest physical therapy seems more to do with the interpretation of the imagery and symptomatology. The airway clearance techniques should be individualised according to symptoms, the amount of expectorated mucus and the objectives signs of secretions retention or subjective signs of difficulty expectorating secretions with progression of the disease.

Factors affecting lower calyceal stone clearance after Extracorporeal shock wave lithotripsy

Directory of Open Access Journals (Sweden)

S. Azab

2013-03-01

Conclusions: There is no statistically significant effect of stone size, anatomy of the lower calyx and BMI on stone clearance after ESWL of lower calyceal stones. However, small stone size (≤2 cm, a shorter and wider infundibulum and a larger lower-pole infundibulopelvic angle seem to promote a more rapid and more complete stone clearance.

Clearance of material with negligible levels of radioactivity based on the amended German radiation protection ordinance

International Nuclear Information System (INIS)

Schaller, G.; Bayer, A.

2002-01-01

For the first time the modalities for the clearance of relevant materials have been laid down in the amended Radiation Protection Ordinance in a comprehensive form. A distinction is made between unconditional clearance and cases of clearance in which disposal, recycling, and re-use is prescribed. The focus of attention in the case of unconditional clearance consists in special consideration of large volumes of building rubble and excavated soil. Material can only be released from supervision under the Atomic Energy Act, when the radiation-related risk, and correspondingly, also the dose from material issued with clearance, are at negligible levels. In order to facilitate the practical application of clearance, values have been derived on the basis of scenarios which cover all radiation exposures which can reasonably be considered. (orig.) [de

Transplacental clearance and blood flows of bovine gravid uterus at several stages of gestation

International Nuclear Information System (INIS)

Reynolds, L.P.; Ferrell, C.L.

1987-01-01

Rates of uterine and umbilical blood flows and transplacental clearance of deuterium oxide (D 2 O) were determined for cows on 137 +/- 1.0 (SE, n = 9), 180 +/- 0.5 (n = 8), 226 +/- 0.4 (n = 9), and 250 +/- 1.8 (n = 5) days of gestation. From days 137 to 250, rates increased 4.5-fold for uterine blood flow, 21-fold for umbilical blood flow, and 14-fold for clearance of D 2 O. Changes in rates of umbilical blood flow and D 2 O clearance paralleled increased rates of fetal growth and metabolism, which have previously been reported to occur during the last half of gestation. The regressions of D 2 O clearance on uterine and umbilical blood flows were significant (P less than 0.01) and explained 94-99% of the variation in placental clearance of D 2 O. Because the rate of D 2 O clearance was always less than that of uterine and umbilical blood flows, and because a relatively simple statistical model explained most of the variation in clearance, it was suggested that a concurrent or countercurrent arrangement of maternal and fetal placental microvasculatures is not adequate to explain clearance of highly diffusable substances across the bovine placenta. In addition, a placental exchange diagram of the data showed the existence of severe uneven distribution of maternal and fetal placental blood flows and/or significant shunting of maternal and fetal placental flows away from areas of exchange. Taken together, these data indicate that the placenta of the cow, like those of the sheep and goat, represents a relatively inefficient system of transplacental exchange

Limitations of regional myocardial thallium clearance for identification of disease in individual coronary arteries

International Nuclear Information System (INIS)

Becker, L.C.; Rogers, W.J. Jr.; Links, J.M.; Corn, C.

1989-01-01

The purpose of this study was to critically evaluate the usefulness of postexercise regional myocardial thallium-201 clearance for identifying disease in individual coronary arteries. Exercise and redistribution planar imaging studies were performed in 114 subjects, including 19 normal volunteers and 95 patients undergoing cardiac catheterization (70 with and 25 without greater than or equal to 50% narrowing in one or more coronary arteries). Thallium clearance was measured from predefined myocardial regions corresponding to the left anterior descending, left circumflex and right coronary arteries and was expressed as the percent decrease in activity at 4 h, assuming monoexponential clearance. In regions perfused by a normal or insignificantly diseased coronary artery, mean 4 h clearance was 58.9 +/- 9.4% for normal volunteers, 43.1 +/- 15.5% for catheterized patients without coronary artery disease and 36.3 +/- 24.9% for catheterized patients with coronary artery disease (p less than 0.001 patients with coronary artery disease versus normal volunteers). Clearance from normal regions was significantly associated with two measures of exercise performance: percent of predicted maximal heart rate achieved (r = 0.49) and exercise duration (r = 0.35). In regions perfused by a stenotic coronary artery, mean clearance was lower (31.1 +/- 19.8%) but was not significantly different from that in normal regions in the same patients. Clearance from diseased regions was also associated with maximal exercise heart rate (r = 0.28) and exercise duration (r = 0.41), but not with percent coronary artery stenosis (r = 0.02). After taking exercise performance into account, the number of diseased vessels or the presence or absence of disease in a given vessel had little influence on regional thallium clearance

Neurogenic plasma exudation mediates grain dust-induced tissue injury in vivo.

Science.gov (United States)

Gao, X P; Von Essen, S; Rubinstein, I

1997-02-01

The purpose of this study was to determine whether an aqueous extract of grain sorghum dust (GDE) elicits neurogenic plasma exudation in the oral mucosa in vivo. Using intravital microscopy, we found that GDE elicited significant, concentration-dependent leaky site formation and an increase in clearance of fluorescein isothiocyanate-labeled dextran (FITC-dextran; mol mass 70 kDa) from the hamster cheek pouch (P grain sorghum dust elicits immediate oral mucosa inflammation in vivo.

Small solute clearance from the lungs of patients with cardiogenic and noncardiogenic pulmonary edema

International Nuclear Information System (INIS)

Mason, G.R.; Effros, R.M.; Uszler, J.M.; Mena, I.

1985-01-01

The regional clearance of /sup 99m/Tc-diethylenetriamine penta-acetate from the lungs was measured in 14 patients with noncardiogenic pulmonary edema, six patients with acute pulmonary edema secondary to heart failure, and 29 normal subjects. The radionuclide was delivered in an aerosol which was inhaled for 120 seconds, and the subsequent decline of radioactivity from the lungs was monitored for seven minutes over each of six peripheral regions of interest with a computerized scintillation camera. The average /sup 99m/Tc-DTPA clearance of these regions was accelerated above the 98 percent confidence limits in all but three of the patients with noncardiogenic edema. The mean clearance value in this group of patients was significantly greater than those in normal subjects or patients with cardiogenic pulmonary edema. Clearances returned toward normal in each of seven subjects who improved clinically. Only one of the patients with cardiogenic pulmonary edema had an elevated average clearance rate, and the mean clearance for this population was not statistically greater than normal. This procedure appears to detect increased epithelial permeability caused by lung injury and may help distinguish between cardiogenic and noncardiogenic pulmonary edema

Waste-clearance strategy for DOE waste processed at commercial facilities

International Nuclear Information System (INIS)

Chen, S.Y.; Pfingston, M.; LePoire, D.

1996-01-01

In May 1991, a moratorium was issued on shipping potentially mixed waste from DOE facilities nationwide to commercial treatment, storage, and disposal facilities. A potential waste-clearance strategy was developed to address the DOE mixed-waste moratorium issues, which had resulted from a lack of exisitng volume contamination regulations. This strategy also has important potential applications for establishing site clearance limits that ensure worker and public risks remain well below regulatory limits

The kidneys play a central role in the clearance of rhGH in rats

DEFF Research Database (Denmark)

Vestergaard, Bill; Thygesen, Peter; Kreilgaard, Mads

2016-01-01

at treatment of patients with growth hormone disorders. The purpose of this study was to investigate the relative importance of the kidneys in the clearance of rhGH. The study employed a newly validated nephrectomy rat model and a population based pharmacokinetic approach to assess renal clearance of rh...... that renal clearance plays a pivotal role in the elimination of rhGH in rats....

Low ground clearance vehicle detection and warning.

Science.gov (United States)

2015-06-01

A Low Ground Clearance Vehicle Detection : System (LGCVDS) determines if a commercial : motor vehicle can successfully clear a highwayrail : grade crossing and notifies the driver when : his or her vehicle cannot safely traverse the : crossing. That ...

The tribological behaviour of different clearance MOM hip joints with lubricants of physiological viscosities.

Science.gov (United States)

Hu, X Q; Wood, R J K; Taylor, A; Tuke, M A

2011-11-01

Clearance is one of the most influential parameters on the tribological performance of metal-on-metal (MOM) hip joints and its selection is a subject of considerable debate. The objective of this paper is to study the lubrication behaviour of different clearances for MOM hip joints within the range of human physiological and pathological fluid viscosities. The frictional torques developed by MOM hip joints with a 50 mm diameter were measured for both virgin surfaces and during a wear simulator test. Joints were manufactured with three different diametral clearances: 20, 100, and 200 microm. The fluid used for the friction measurements which contained different ratios of 25 percent newborn calf serum and carboxymethyl cellulose (CMC) with the obtained viscosities values ranging from 0.001 to 0.71 Pa s. The obtained results indicate that the frictional torque for the 20 microm clearance joint remains high over the whole range of the viscosity values. The frictional torque of the 100 microm clearance joint was low for the very low viscosity (0.001 Pa s) lubricant, but increased with increasing viscosity value. The frictional torque of the 200 microm clearance joint was high at very low viscosity levels, however, it reduced with increasing viscosity. It is concluded that a smaller clearance level can enhance the formation of an elastohydrodynamic lubrication (EHL) film, but this is at the cost of preventing fluid recovery between the bearing surfaces during the unloaded phase of walking. Larger clearance bearings allow a better recovery of lubricant during the unloaded phase, which is necessary for higher viscosity lubricants. The selection of the clearance value should therefore consider both the formation of the EHL film and the fluid recovery as a function of the physiological viscosity in order to get an optimal tribological performance for MOM hip joints. The application of either 25 per cent bovine serum or water in existing in vitro tribological study should

Proficiency testing criteria for clearance level in solid waste gamma measurement in Taiwan.

Science.gov (United States)

Chen, Chun-Liang; Wang, Jeng-Jong; Chiu, Huang-Sheng

2013-11-01

To guarantee the measurement quality for clearance level in solid waste material, the Institute of Nuclear Energy Research (INER) established the criteria for proficiency testing of clearance level measurement. INER and the Taiwan Accreditation Foundation (TAF) organized the Technique Committee Meeting twice to discuss these criteria in 2011. The participating laboratories must completely conform to the ISO/IEC 17025, and they also must meet the requirements of the criteria. According to the criteria, the participating laboratories analyzed the minimum detectable amount (MDA) and that should be less than 20% of the clearance level (AMDA) given in the Atomic Energy Council's (AEC) "Regulations on Clearance Level for Radioactive Waste Management". The testing results should conform to the deviation and traceability requirements. Copyright © 2013 Elsevier Ltd. All rights reserved.

Not All Children with Cystic Fibrosis Have Abnormal Esophageal Neutralization during Chemical Clearance of Acid Reflux.

Science.gov (United States)

Woodley, Frederick W; Moore-Clingenpeel, Melissa; Machado, Rodrigo Strehl; Nemastil, Christopher J; Jadcherla, Sudarshan R; Hayes, Don; Kopp, Benjamin T; Kaul, Ajay; Di Lorenzo, Carlo; Mousa, Hayat

2017-09-01

Acid neutralization during chemical clearance is significantly prolonged in children with cystic fibrosis, compared to symptomatic children without cystic fibrosis. The absence of available reference values impeded identification of abnormal findings within individual patients with and without cystic fibrosis. The present study aimed to test the hypothesis that significantly more children with cystic fibrosis have acid neutralization durations during chemical clearance that fall outside the physiological range. Published reference value for acid neutralization duration during chemical clearance (determined using combined impedance/pH monitoring) was used to assess esophageal acid neutralization efficiency during chemical clearance in 16 children with cystic fibrosis (3 to chemical clearance exceeded the upper end of the physiological range in 9 of 16 (56.3%) children with and in 3 of 16 (18.8%) children without cystic fibrosis ( p =0.0412). The likelihood ratio for duration indicated that children with cystic fibrosis are 2.1-times more likely to have abnormal acid neutralization during chemical clearance, and children with abnormal acid neutralization during chemical clearance are 1.5-times more likely to have cystic fibrosis. Significantly more (but not all) children with cystic fibrosis have abnormally prolonged esophageal clearance of acid. Children with cystic fibrosis are more likely to have abnormal acid neutralization during chemical clearance. Additional studies involving larger sample sizes are needed to address the importance of genotype, esophageal motility, composition and volume of saliva, and gastric acidity on acid neutralization efficiency in cystic fibrosis children.

Technetium-99m mercaptoacetyltriglycine clearance values in children with minimal renal disease: can a normal range be determined?

International Nuclear Information System (INIS)

Meyer, G.; Hahn, K.; Piepsz, A.; Kolinska, J.; Lepej, J.; Sixt, R.

1998-01-01

Use of technetium-99m labelled mercaptoacetyltriglycine ( 99m Tc-MAG3) simplifies and improves the quantification of renal clearance in children by virtue of its permanent availability, good imaging properties and low radiation exposure. Due to the lack of reference values for 99m Tc-MAG3 clearance in children, the Paediatric Task Group of the EANM initiated a multicentre study to evaluate 99m Tc-MAG3 clearance values in children with minimal renal disease. One hundred and twenty-five children aged between 12 months and 17 years, classified as renally healthy using defined diagnostic criteria, were included in the study. 99m Tc-MAG3 clearance was calculated using an algorithm on the basis of a single blood sample taken at any time between 30 and 40 min after tracer injection. In addition, the absolute 99m -Tc-MAG3 clearance values were normalized to body surface area. For further evaluation the children were classified into several groups according to age. There was a continuous increase in non-corrected 99m Tc-MAG3 clearance values from the age of 1 year up to the age of 17 years (mean value 8 years: 208±66 ml/min). Normal clearance values for adults were achieved by the age of 8 years. Analysis of the relationship between non-corrected clearance and age yielded a correlation coefficient of r=0.7. When these absolute clearance values were normalized to body surface area, we found nearly constant clearance values for all age groups, with a mean clearance value of 315±114 ml/min x 1.73 m 2 . The correlation coefficient for the relationship between normalized clearance and age was r=0.28. In conclusion, the clearance of 99m Tc-MAG3 increases continuously throughout childhood into adolescence due to the maturation and growth of the kidney. After normalization of the absolute clearance to body surface area, no correlation between clearance and age could be proven. (orig.)

Trend of research and development on clearance system for CBRNE agents

International Nuclear Information System (INIS)

Ishihara, Masayuki; Fujita, Masanori; Ishida, Natsuko; Hattori, Hidemi; Tachibana, Shoich; Nakamura, Shingo; Kanatani, Yasuhiro

2013-01-01

In a field of disaster for a wide variety of Chemical, Biological, Radiological, Nuclear, Explosive (CBRNE) agents which are harmful and deadly poisonous, it is crucial to effectively clear those agents for prevention of expanded damages and retrieval from damage. The clearance technologies in the CBRNE disaster field require to be safe for human body and to be friendly for the environments. In addition, they need scientific data-based evidences for their effectiveness and safety. The aim of this article is to view the trend of research on clearances of N, B and c agents in terms of rapidity, simplicity and economic rationality, and to deliberate on effective clearance system using adequate equipments and materials for detoxification, decomposition and removal of each contamination. (author)

Rate-Based Model Predictive Control of Turbofan Engine Clearance

Science.gov (United States)

DeCastro, Jonathan A.

2006-01-01

An innovative model predictive control strategy is developed for control of nonlinear aircraft propulsion systems and sub-systems. At the heart of the controller is a rate-based linear parameter-varying model that propagates the state derivatives across the prediction horizon, extending prediction fidelity to transient regimes where conventional models begin to lose validity. The new control law is applied to a demanding active clearance control application, where the objectives are to tightly regulate blade tip clearances and also anticipate and avoid detrimental blade-shroud rub occurrences by optimally maintaining a predefined minimum clearance. Simulation results verify that the rate-based controller is capable of satisfying the objectives during realistic flight scenarios where both a conventional Jacobian-based model predictive control law and an unconstrained linear-quadratic optimal controller are incapable of doing so. The controller is evaluated using a variety of different actuators, illustrating the efficacy and versatility of the control approach. It is concluded that the new strategy has promise for this and other nonlinear aerospace applications that place high importance on the attainment of control objectives during transient regimes.

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

Science.gov (United States)

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.

Cerebrospinal fluid clearance in Alzheimer disease measured with dynamic PET

DEFF Research Database (Denmark)

De Leon, Mony J.; Li, Yi; Okamura, Nobuyuki

2017-01-01

Evidence supporting the hypothesis that reduced cerebrospinal fluid (CSF) clearance is involved in the pathophysiology of Alzheimer disease (AD) comes primarily from rodent models. However, unlike rodents, in which predominant extracranial CSF egress is via olfactory nerves traversing the cribrif......Evidence supporting the hypothesis that reduced cerebrospinal fluid (CSF) clearance is involved in the pathophysiology of Alzheimer disease (AD) comes primarily from rodent models. However, unlike rodents, in which predominant extracranial CSF egress is via olfactory nerves traversing...

Influence of tip clearance on flow behavior and noise generation of centrifugal compressors in near-surge conditions

International Nuclear Information System (INIS)

Galindo, J.; Tiseira, A.; Navarro, R.; López, M.A.

2015-01-01

Highlights: • Centrifugal compressor aeroacoustics sensitivity to tip clearance is investigated. • 3 different clearance ratios are set in accordance to expected operating values. • Pressure spectra do not depend on tip clearance ratio in near-surge conditions. • DES performs better than URANS in predicting compressor acoustic signature. • Flow field observation reveals that tip clearance is immersed in rotating backflow. - Abstract: CFD has become an essential tool for researchers to analyze centrifugal compressors. Tip leakage flow is usually considered one of the main mechanisms that dictate compressor flow field and stability. However, it is a common practice to rely on CAD tip clearance, even though the gap between blades and shroud changes when compressor is running. In this paper, sensitivity of centrifugal compressor flow field and noise prediction to tip clearance ratio is investigated. 3D CFD simulations are performed with three different tip clearance ratios in accordance to expected operating values, extracted from shaft motion measurements and FEM predictions of temperature and rotational deformation. Near-surge operating conditions are simulated with URANS and DES. DES shows superior performance for acoustic predictions. Cases with reduced tip clearance present higher pressure ratio and isentropic efficiency, but no significant changes in compressor acoustic signature are found when varying clearance. In this working point, tip clearance is immersed in a region of strongly swirling backflow. Therefore, tip leakage cannot establish any coherent noise source mechanism

The Swedish nuclear industry way to approach higher demands on characterisation prior to clearance

International Nuclear Information System (INIS)

Larsson, Arne; Hellsten, Erik; Berglund, Malin; Larsson, Lars

2012-01-01

The Swedish Radiation Safety Authority (SSM) has introduced new regulations for clearance SSMFS 2011:2 'Regulations concerning clearance of material, rooms, buildings and soil from activities with ionizing radiation'. The new regulations came into force January 1, 2012. Compared to the previous regulations these new regulations have a broader scope and have introduced new conditions such as nuclide specific clearance levels. Clearance is practiced to reduce the amount of radioactive waste generated. Cleared material can be reused, recycled or if these two possibilities are not available, disposed of as conventional waste. To be able to meet the requirements for clearance the Swedish nuclear industry has jointly developed guidance for clearance in the form of a handbook and a training course covering the competence requirements in the new regulations. The handbook was developed by a team of representatives from the Swedish nuclear license holders managed by Studsvik on behalf of Swedish Nuclear Fuel and Waste Management Company (SKB). The training program was developed in co-operation between Nuclear Safety and training Company (KSU) and Studsvik on behalf of the Swedish nuclear license holders. A major challenge in the adoption to the new regulations is how to provide robust yet cost effective characterisation data. This is especially difficult for mobile materials and equipment which cannot be fully tracked but also for other materials and areas where the nuclide fingerprint has varied over the years. To be able to deal with these issues a lot of attention has to be paid to the historical inventory records and traceability in the clearance process. Materials, rooms and buildings have been divided in four categories with different requirements on frequency and requirements of measurements. The categories are named 'extremely small risk', 'small risk', 'risk' and 'known contamination above clearance levels'. The two day training course is dived into seven parts

Decision Assessment of Clearance Level on Radioactive Waste Management

International Nuclear Information System (INIS)

Zainus Salimin; Gunandjar

2007-01-01

Radioactive waste on the safe level activity containing very small radioactive material gives small radiology influence to the human, it is not necessary to control by regulatory body. The radioactive waste on the safe level activity is safe to release as the common waste. For exemption of the control, it is required the safe activity level limits in which the value of clearance level is fulfilled by regulatory body, however until now it is not decided yet. The exemption decision is obtained if its activity is lower than or same with clearance level based on the annual effective dose receiving by public on the value is lower than or same with 0,01 mSv. The exposure pathways of radioactive waste to the human have important role for determination of clearance level. The decision assessment of clearance level on the radioactive waste management has been done by analysis of radioactive exposure pathways to the human for activities of the disposal and the recycle of solid wastes, also the release of liquid and gas effluent. For solid waste disposal, the exposure pathway was evaluated since the transportation of packed waste from the treatment facility to the disposal facility and during its operation. Exposure pathways for solid waste recycle consist of the pathways for handling and transportation of cleared material to the recycling facility, the fabrication and the utilization of its product. Exposure pathways for liquid and gas releases occur since its releases to the environment up to the human (public) by specific traffic lane. (author)

Modeling Zika plasma viral dynamics in non-human primates: insights into viral pathogenesis and antiviral strategies

Energy Technology Data Exchange (ETDEWEB)

Best, Katharine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Guedj, Jeremie [Univ. of Paris (France). IAME; Madelain, Vincent [Univ. of Paris (France); de Lamballerie, Xavier [Aix-Marseille Univ. (France); L, So-Yonim [Harvard Univ., Cambridge, MA (United States). Center for Virology and Vaccine Research; Osuna, Christa E [Harvard Univ., Cambridge, MA (United States). Center for Virology and Vaccine Research; Whitney, James [Harvard Univ., Cambridge, MA (United States). Center for Virology and Vaccine Research; Perelson, Alan S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-10-24

The recent outbreak of Zika virus (ZIKV) has been associated with fetal abnormalities and neurological complications, prompting global concern. Here we present the first mathematical analysis of the within-host dynamics of plasma ZiKV burden in a non-human primate model, allowing for characterization of the growth and clearance of ZIKV within an individual macaque.

Bromsulphalein (BSP) clearance in ageing rats

NARCIS (Netherlands)

Hollander, C.F.; Leeuw-Israel, F.R. de; Arp-Neefjes, J.M.

1968-01-01

Liver function in ageing rats was studied, using the bromsulphalein (BSP) clearance test. The test was done on ultramicro scale. This made it possible to repeat the test several times in the same animal and to start a longitudinal study. In 3-month-old rats the BSP retentions, measured 15, 30 and 45

Non-destructive clearance measuring in closed joints

International Nuclear Information System (INIS)

Doucelance, C.; Manaranche, J.C.

1976-01-01

Two methods for clearance measuring in closed joints are described. The first one is based on the mechanical impedance concept, while the other one requires a shock test on shaker. Both are illustrated with an example of application [fr

Hyperinsulinism and polycystic ovary syndrome (PCOS): role of insulin clearance.

Science.gov (United States)

Amato, M C; Vesco, R; Vigneri, E; Ciresi, A; Giordano, C

2015-12-01

Insulin resistance and compensatory hyperinsulinism are the predominant metabolic defects in polycystic ovary syndrome (PCOS). However, hyperinsulinism, as well as being compensatory, can also express a condition of reduced insulin clearance. Our aim was to evaluate the differences in insulin action and metabolism between women with PCOS (with normal glucose tolerance) and age- and BMI-matched women with prediabetes (without hyperandrogenism and ovulatory disorders). 22 women with PCOS and 21 age/BMI-matched women with prediabetes were subjected to a Hyperinsulinemic-euglycemic clamp and an Oral Glucose tolerance Test (OGTT). Insulin sensitivity was assessed by the glucose infusion rate during clamp (M value); insulin secretion by Insulinogenic index, Oral Disposition Index (DIo) and AUC(2h-insulin) during OGTT; and insulin clearance by the metabolic clearance rate of insulin (MCRI) during clamp. Women with PCOS showed significantly higher levels of AUC(2h-insulin) (p PCOS [420 (IQR 227-588) vs. 743 (IQR 597-888) ml m(-2) min(-1): p PCOS group, a strong independent inverse correlation was only observed between MCRI and AUC(2h-insulin) (PCOS: β:-0.878; p PCOS there is peripheral insulin sensitivity similar to that of women with prediabetes. What sets PCOS apart is the hyperinsulinism, today still simplistically defined "compensatory"; actually this is mainly related to decreased insulin clearance whose specific causes and dynamics have yet to be clarified.

133 xenon muscle clearance as a test parameter in the diagnosis of peripheral diabetic angiopathies

International Nuclear Information System (INIS)

Kuhlmann, J.E.

1980-01-01

In 100 patients with manifest diabetes mellitus the irrigation in both legs at rest and in radioactive hyperemia after ischemic muscle work was measured by means of the 133-xenon muscle clearance. The clearance values measured ranged between 0.8 and 3.5 ml/100 g/60 s at rest and between 3.3 and 40.0 ml/100 gl/60 s during radioactive hyperemia. In 96 pc of the probands the irrigation of the legs was impaired. For the relation between glucose level and irrigation at rest a significant negative correlation was found. The difference between the clearance values for the right and left lower extremity was significant. For the relation between glucose level and reactive hyperemia, too, a significant negative correlation was found. The difference between the clearance values for the right and left lower extremities was significant. The measurement of the irrigation at rest showed no significant correlation between the period of manifestation of the diabetes and the clearance values. By contrast, the irrigation values during reactive hyperemia were shown to be in significantly negative correlation to the duration of the diabetes. No connection was found between the frequency of diabetic gangrene and impaired irrigation at rest. By contrast, there was a relation between decreasing hyperemia values and increased frequency of gangrene. A collection of case histories shows how the measuring results of the xenon clearance fit into the overall clinical picture. A comparison of xenon clearance with other methods of irrigation measurement confirmed obvious advantages of xenon clearance for the detection of diabetic microangiopathies. (orig./MG) [de

Serial thallium-201 imaging after dipyridamole for coronary disease detection: quantitative analysis using myocardial clearance

International Nuclear Information System (INIS)

Okada, R.D.; Dai, Y.H.; Boucher, C.A.; Pohost, G.M.

1984-01-01

After dipyridamole, canine studies have demonstrated a slower rate of myocardial thallium-201 clearance from zones distal to a coronary artery stenosis compared to normal zones. To determine if criteria based on canine myocardial thallium-201 clearance rates could be applied clinically, 40 patients with and 26 patients without coronary artery disease (CAD) had serial thallium-201 images obtained for 2 to 5 hours after dipyridamole. Regions of interest were manually placed over six left ventricular segments in two projections for each of three imaging times. The myocardial thallium-201 clearance rate was calculated for each of the six segments and, using the clearance rate criterion found in canine studies, was considered abnormal if less than 6.5%/hr. Using this criterion alone, 22 of 26 patients (85%) without CAD had normal and 30 of 40 patients (75%) with CAD had abnormal myocardial thallium-201 clearance rates. A quantitative analysis of regional inhomogeneity in tracer distribution (normal was greater than or equal to 25% difference between segments) was negative in 24 of 26 patients (92%) without CAD and positive in 20 of 40 patients (50%) with CAD. When both clearance rate and regional inhomogeneity were considered, 21 of 26 patients (81%) without CAD had negative and 36 of 40 patients (90%) with CAD had positive results. Thus, post-dipyridamole myocardial clearance rate criteria derived from canine studies can be applied to clinical thallium imaging. Quantitative analysis of serial thallium-201 images after dipyridamole is optimized by using myocardial thallium-201 clearance rates. Such an approach is independent of regional inhomogeneities in tracer distribution

High salt intake increases plasma trimethylamine N-oxide (TMAO) concentration and produces gut dysbiosis in rats.

Science.gov (United States)

Bielinska, Klaudia; Radkowski, Marek; Grochowska, Marta; Perlejewski, Karol; Huc, Tomasz; Jaworska, Kinga; Motooka, Daisuke; Nakamura, Shota; Ufnal, Marcin

2018-03-22

A high-salt diet is considered a cardiovascular risk factor; however, the mechanisms are not clear. Research suggests that gut bacteria-derived metabolites such as trimethylamine N-oxide (TMAO) are markers of cardiovascular diseases. We evaluated the effect of high salt intake on gut bacteria and their metabolites plasma level. Sprague Dawley rats ages 12-14 wk were maintained on either water (controls) or 0.9% or 2% sodium chloride (NaCl) water solution (isotonic and hypertonic groups, respectively) for 2 wk. Blood plasma, urine, and stool samples were analyzed for concentrations of trimethylamine (TMA; a TMAO precursor), TMAO, and indoxyl sulfate (indole metabolite). The gut-blood barrier permeability to TMA and TMA liver clearance were assessed at baseline and after TMA intracolonic challenge test. Gut bacterial flora was analyzed with a 16S ribosomal ribonucleic acid (rRNA) gene sequence analysis. The isotonic and hypertonic groups showed a significantly higher plasma TMAO and significantly lower 24-hr TMAO urine excretion than the controls. However, the TMA stool level was similar between the groups. There was no significant difference between the groups in gut-blood barrier permeability and TMA liver clearance. Plasma indoxyl concentration and 24-hr urine indoxyl excretion were similar between the groups. There was a significant difference between the groups in gut bacteria composition. High salt intake increases plasma TMAO concentration, which is associated with decreased TMAO urine excretion. Furthermore, high salt intake alters gut bacteria composition. These findings suggest that salt intake affects an interplay between gut bacteria and their host homeostasis. Copyright © 2018 Elsevier Inc. All rights reserved.

TAM receptors in apoptotic cell clearance, autoimmunity, and cancer.

Science.gov (United States)

Nguyen, Khanh-Quynh; Tsou, Wen-I; Kotenko, Sergei; Birge, Raymond B

2013-08-01

Receptor tyrosine kinases, Tyro-3, Axl and Mer, collectively designated as TAM, are involved in the clearance of apoptotic cells. TAM ligands, Gas6 and Protein S, bind to the surfaces of apoptotic cells, and at the same time, interact directly with TAM expressed on phagocytes, impacting the engulfment and clearance of apoptotic cells and debris. The well-tuned and balanced actions of TAM may affect a variety of human pathologies including autoimmunity, retinal degeneration, and cancer. This article emphasizes some of the emerging findings and mechanistic insights into TAM functions that are clinically relevant and possibly therapeutically targeted.

Clearance of buildings for demolition: ways to clearance on the standing structure for covered surfaces and inaccessible areas

International Nuclear Information System (INIS)

Thraenert, S.; Riemann, T.

2014-01-01

In general terms, the TUV NORD Nuclear services encompass safety assessments, design reviews, documentation re-views and inspections. They reflect the full scope of a technical service provider in the nuclear field. In the domestic market, these services are provided for the regulator, whereas in the international market any party involved in a nuclear project is a potential customer of TUV NORD Nuclear. This implies that TUV NORD Nuclear is offering consultancy, engineering and inspection services. Regarding the clearance of buildings for demolition, there are two different possible ways for the radiological characterization. The first option is a characterization on the standing structure before demolition and the second option is the characterization of the building rubble after demolition. According to the German Radiation Protection Ordinance, buildings of decommissioned nuclear sites have to be preferentially cleared on the standing structure. If compliance with the surface specific clearance levels is achieved on the standing structure, usually the cleared buildings can be demolished and the resulting rubble may be used without any further radiological considerations. In the case of the former nuclear power plant Wuergassen the majority of the building rubble is scheduled to stay on site to serve as backfill for the building pit. As such a scenario was not considered in the radiological considerations of, e.g., the German Radiation Protection Ordinance, an additional dose calculation was carried out for Wuergassen NPP basing on its radiological characteristics to directly prove compliance with the de-minimis-concept. The radiation controlled area (RCA) of Wuergassen NPP comprises an area of about 140.000 m 2 . This area is more or less easily accessible to characterization and decontamination using, if necessary, scaffoldings or lifting platforms. Up to the beginning of 2013, compliance with the surface specific clearance levels was verified on the standing

Lithium clearance and renal tubular sodium handling during acute and long-term nifedipine treatment in essential hypertension

DEFF Research Database (Denmark)

Bruun, N E; Ibsen, H; Skøtt, P

1988-01-01

1. In two separate studies the lithium clearance method was used to evaluate the influence of acute and long-term nifedipine treatment on renal tubular sodium reabsorption. 2. In the acute study, after a 4 week placebo period two doses of 20 mg of nifedipine decreased supine blood pressure from 155...... were also unchanged, as were potassium clearance, urine flow and body weight. 3. In the long-term study, lithium clearance, glomerular filtration rate, sodium clearance, potassium clearance, urine flow and body fluid volumes were measured after a 4 weeks placebo period and after 6 and 12 weeks....../101 (20.6/13.5) +/- 11/4 (1.5/0.5) to 139/88 (18.5/11.7) +/- 16/9 (2.1/1.2) mmHg (kPa) (means +/- SD; P less than 0.01). Lithium clearance, glomerular filtration rate and sodium clearance did not change. Therefore the calculated values of absolute proximal and absolute distal sodium reabsorption rates...

Effect of tip clearance on performance of small axial hydraulic turbine

Science.gov (United States)

Boynton, J. L.; Rohlik, H. E.

1976-01-01

The first two stages of a six stage liquid oxygen turbine were tested in water. One and two stage performance was determined for one shrouded and two unshrouded blade end configurations over ranges of clearance and blade-jet speed ratio. First stage, two stage, and second stage efficiencies are included as well as the effect of clearance on mass flow for two stage operation.

Thickness and clearance visualization based on distance field of 3D objects

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Masatomo Inui

2015-07-01

Full Text Available This paper proposes a novel method for visualizing the thickness and clearance of 3D objects in a polyhedral representation. The proposed method uses the distance field of the objects in the visualization. A parallel algorithm is developed for constructing the distance field of polyhedral objects using the GPU. The distance between a voxel and the surface polygons of the model is computed many times in the distance field construction. Similar sets of polygons are usually selected as close polygons for close voxels. By using this spatial coherence, a parallel algorithm is designed to compute the distances between a cluster of close voxels and the polygons selected by the culling operation so that the fast shared memory mechanism of the GPU can be fully utilized. The thickness/clearance of the objects is visualized by distributing points on the visible surfaces of the objects and painting them with a unique color corresponding to the thickness/clearance values at those points. A modified ray casting method is developed for computing the thickness/clearance using the distance field of the objects. A system based on these algorithms can compute the distance field of complex objects within a few minutes for most cases. After the distance field construction, thickness/clearance visualization at a near interactive rate is achieved.

Soluble Receptor for Advanced Glycation End-Products Predicts Impaired Alveolar Fluid Clearance in Acute Respiratory Distress Syndrome.

Science.gov (United States)

Jabaudon, Matthieu; Blondonnet, Raiko; Roszyk, Laurence; Bouvier, Damien; Audard, Jules; Clairefond, Gael; Fournier, Mathilde; Marceau, Geoffroy; Déchelotte, Pierre; Pereira, Bruno; Sapin, Vincent; Constantin, Jean-Michel

2015-07-15

Levels of the soluble form of the receptor for advanced glycation end-products (sRAGE) are elevated during acute respiratory distress syndrome (ARDS) and correlate with severity and prognosis. Alveolar fluid clearance (AFC) is necessary for the resolution of lung edema but is impaired in most patients with ARDS. No reliable marker of this process has been investigated to date. To verify whether sRAGE could predict AFC during ARDS. Anesthetized CD-1 mice underwent orotracheal instillation of hydrochloric acid. At specified time points, lung injury was assessed by analysis of blood gases, alveolar permeability, lung histology, AFC, and plasma/bronchoalveolar fluid measurements of proinflammatory cytokines and sRAGE. Plasma sRAGE and AFC rates were also prospectively assessed in 30 patients with ARDS. The rate of AFC was inversely correlated with sRAGE levels in the plasma and the bronchoalveolar fluid of acid-injured mice (Spearman's ρ = -0.73 and -0.69, respectively; P < 10(-3)), and plasma sRAGE correlated with AFC in patients with ARDS (Spearman's ρ = -0.59; P < 10(-3)). Similarly, sRAGE levels were significantly associated with lung injury severity, and decreased over time in mice, whereas AFC was restored and lung injury resolved. Our results indicate that sRAGE levels could be a reliable predictor of impaired AFC during ARDS, and should stimulate further studies on the pathophysiologic implications of RAGE axis in the mechanisms leading to edema resolution. Clinical trial registered with www.clinicaltrials.gov (NCT 00811629).

Energy Performance and Radial Force of a Mixed-Flow Pump with Symmetrical and Unsymmetrical Tip Clearances

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Yue Hao

2017-01-01

Full Text Available The energy performance and radial force of a mixed flow pump with symmetrical and unsymmetrical tip clearance are investigated in this paper. As the tip clearance increases, the pump head and efficiency both decrease. The center of the radial force on the principal axis is located at the coordinate origin when the tip clearance is symmetrical, and moves to the third quadrant when the tip clearance is unsymmetrical. Analysis results show that the total radial force on the principal axis is closely related to the fluctuation of mass flow rate in each single flow channel. Unsteady simulations show that the dominant frequencies of radial force on the hub and blade correspond to the blade number, vane number, or double blade number because of the rotor stator interaction. The radial force on the blade pressure side decreases with the tip clearance increase because of leakage flow. The unsymmetrical tip clearances in an impeller induce uneven leakage flow rate and then result in unsymmetrical work ability of each blade and flow pattern in each channel. Thus, the energy performance decreases and the total radial force increases for a mixed flow pump with unsymmetrical tip clearance.

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Measurement of plasma adenosine concentration: methodological and physiological considerations

International Nuclear Information System (INIS)

Gewirtz, H.; Brown, P.; Most, A.S.

1987-01-01

This study tested the hypothesis that measurements of plasma adenosine concentration made on samples of blood obtained in dipyridamole and EHNA (i.e., stopping solution) may be falsely elevated as a result of ongoing in vitro production and accumulation of adenosine during sample processing. Studies were performed with samples of anticoagulated blood obtained from anesthesized domestic swine. Adenosine concentration of ultra filtrated plasma was determined by HPLC. The following parameters were evaluated: (i) rate of clearance of [ 3 H]adenosine added to plasma, (ii) endogenous adenosine concentration of matched blood samples obtained in stopping solution alone, stopping solution plus EDTA, and perchloric acid (PCA), (iii) plasma and erythrocyte endogenous adenosine concentration in nonhemolyzed samples, and (iv) plasma adenosine concentration of samples hemolyzed in the presence of stopping solution alone or stopping solution plus EDTA. We observed that (i) greater than or equal to 95% of [ 3 H]adenosine added to plasma is removed from it by formed elements of the blood in less than 20 s, (ii) plasma adenosine concentration of samples obtained in stopping solution alone is generally 10-fold greater than that of matched samples obtained in stopping solution plus EDTA, (iii) deliberate mechanical hemolysis of blood samples obtained in stopping solution alone resulted in substantial augmentation of plasma adenosine levels in comparison with matched nonhemolyzed specimens--addition of EDTA to stopping solution prevented this, and (iv) adenosine content of blood samples obtained in PCA agreed closely with the sum of plasma and erythrocyte adenosine content of samples obtained in stopping solution plus EDTA

Turbine Engine Clearance Control Systems: Current Practices and Future Directions

Science.gov (United States)

Lattime, Scott B.; Steinetz, Bruce M.

2002-01-01

Improved blade tip sealing in the high pressure compressor (HPC) and high pressure turbine (HPT) can provide dramatic reductions in specific fuel consumption (SFC), time-on-wing, compressor stall margin, and engine efficiency as well as increased payload and mission range capabilities. Maintenance costs to overhaul large commercial gas turbine engines can easily exceed $1M. Engine removal from service is primarily due to spent exhaust gas temperature (EGT) margin caused mainly by the deterioration of HPT components. Increased blade tip clearance is a major factor in hot section component degradation. As engine designs continue to push the performance envelope with fewer parts and the market drives manufacturers to increase service life, the need for advanced sealing continues to grow. A review of aero gas turbine engine HPT performance degradation and the mechanisms that promote these losses are discussed. Benefits to the HPT due to improved clearance management are identified. Past and present sealing technologies are presented along with specifications for next generation engine clearance control systems.

Regulation Concepts for Clearance Level of Radionuclide in Solid Materials

International Nuclear Information System (INIS)

Nanang Triagung Edi Hermawan

2008-01-01

Practices of nuclear energy have expanded in some fields such as researches and development, educations, agricultures, medicines and industries. Every practice beside give much benefit, could generate residue or waste. Radioactive waste needs management to ensure the safety of workers, member of the public, and for the eternal of environment. The product of radioactive waste management, in generally, is some containment of radionuclide concentration in solid matrix material after immobilization or conditioning process. Some kind of processed radioactive wastes with short half live then decay faster to stabile condition. The decay will reach clearance level in sometimes, so from the radiation protection views is harmless. This materials above didn’t need control and must be cleared from all determinate and regulation aspects of radioactive material practices. There is clearance for harmless material off course will be simplify management task and efficiency of money. So the regulation about clearance levels will be important as law basic for technical practices in field. (author)

Dynamic Studies of Lung Fluid Clearance with Phase Contrast Imaging

International Nuclear Information System (INIS)

Kitchen, Marcus J.; Williams, Ivan; Irvine, Sarah C.; Morgan, Michael J.; Paganin, David M.; Lewis, Rob A.; Pavlov, Konstantin; Hooper, Stuart B.; Wallace, Megan J.; Siu, Karen K. W.; Yagi, Naoto; Uesugi, Kentaro

2007-01-01

Clearance of liquid from the airways at birth is a poorly understood process, partly due to the difficulties of observing and measuring the distribution of air within the lung. Imaging dynamic processes within the lung in vivo with high contrast and spatial resolution is therefore a major challenge. However, phase contrast X-ray imaging is able to exploit inhaled air as a contrast agent, rendering the lungs of small animals visible due to the large changes in the refractive index at air/tissue interfaces. In concert with the high spatial resolution afforded by X-ray imaging systems (<100 μm), propagation-based phase contrast imaging is ideal for studying lung development. To this end we have utilized intense, monochromatic synchrotron radiation, together with a fast readout CCD camera, to study fluid clearance from the lungs of rabbit pups at birth. Local rates of fluid clearance have been measured from the dynamic sequences using a single image phase retrieval algorithm

Understanding of the Interaction between Clearance Leakage Flow and Main Passage Flow in a VGT Turbine

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Ben Zhao

2015-02-01

Full Text Available The clearance flow between the nozzle and endwall in a variable geometry turbine (VGT has been numerically investigated to understand the clearance effect on the VGT performance and internal flow. It was found that the flow rate through turbine increases but the turbine efficiency decreases with height of clearance. Detailed flow field analyses indicated that most of the efficiency loss resulting from the leakage flow occurs at the upstream of the rotor area, that is, in the nozzle endwall clearance and between the nozzle vanes. There are two main mechanisms associated with this efficiency loss. One is due to the formation of the local vortex flow structure between the clearance flow and the main flow. The other is due to the impact of the clearance flow on the main flow after the nozzle throat. This impact reduces the span of shockwave with increased shockwave magnitude by changing the trajectory of the main flow.

Population Pharmacokinetics of Meropenem in Plasma and Subcutis in Patients on Extracorporeal Membrane Oxygenation Treatment

DEFF Research Database (Denmark)

Hanberg, Pelle; Öbrink-Hansen, Kristina; Thorsted, Anders

2018-01-01

The objectives of this study were to describe meropenem pharmacokinetics (PK) in plasma and/or subcutaneous adipose tissue (SCT) in critically ill patients receiving ECMO treatment, and to develop a population PK model to simulate alternative dosing regimens and modes of administration. We...... conducted a prospective observational study. Ten patients on ECMO treatment received meropenem (1 or 2 g) intravenously over 5 min every 8 hours. Serial SCT concentrations were determined using microdialysis and compared with plasma concentrations. A population PK model of SCT and plasma data was developed...... infusion would be needed for 100%fT>MIC and 100%fT>4xMIC to be obtained. Meropenem plasma and SCT concentrations were associated with estimated creatinine-clearance (eCLCr). Simulations showed that in patients with increased eCLCr, dose increment or continuous infusion may be needed to obtain therapeutic...

Plasma Levels of Middle Molecules to Estimate Residual Kidney Function in Haemodialysis without Urine Collection.

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Enric Vilar

Full Text Available Residual Kidney Function (RKF is associated with survival benefits in haemodialysis (HD but is difficult to measure without urine collection. Middle molecules such as Cystatin C and β2-microglobulin accumulate in renal disease and plasma levels have been used to estimate kidney function early in this condition. We investigated their use to estimate RKF in patients on HD.Cystatin C, β2-microglobulin, urea and creatinine levels were studied in patients on incremental high-flux HD or hemodiafiltration(HDF. Over sequential HD sessions, blood was sampled pre- and post-session 1 and pre-session 2, for estimation of these parameters. Urine was collected during the whole interdialytic interval, for estimation of residual GFR (GFRResidual = mean of urea and creatinine clearance. The relationships of plasma Cystatin C and β2-microglobulin levels to GFRResidual and urea clearance were determined.Of the 341 patients studied, 64% had urine output>100 ml/day, 32.6% were on high-flux HD and 67.4% on HDF. Parameters most closely correlated with GFRResidual were 1/β2-micoglobulin (r2 0.67 and 1/Cystatin C (r2 0.50. Both these relationships were weaker at low GFRResidual. The best regression model for GFRResidual, explaining 67% of the variation, was: GFRResidual = 160.3 · (1/β2m - 4.2. Where β2m is the pre-dialysis β2 microglobulin concentration (mg/L. This model was validated in a separate cohort of 50 patients using Bland-Altman analysis. Areas under the curve in Receiver Operating Characteristic analysis aimed at identifying subjects with urea clearance≥2 ml/min/1.73 m2 was 0.91 for β2-microglobulin and 0.86 for Cystatin C. A plasma β2-microglobulin cut-off of ≤19.2 mg/L allowed identification of patients with urea clearance ≥2 ml/min/1.73 m2 with 90% specificity and 65% sensitivity.Plasma pre-dialysis β2-microglobulin levels can provide estimates of RKF which may have clinical utility and appear superior to cystatin C. Use of cut-off levels

The effects of selected air pollutants on clearance of titanic oxide particles from the lungs of rats.

Science.gov (United States)

Ferin, J; Leach, L J

1975-09-01

A procedure utilizing the lung clearance kinetics of titanic oxide (TiO2) particles was used to determine the effects of inhaled sulphur dioxide (SO2) and nitrogen oxides (NO x) on particle clearance. The procedure is reproducible and mainly tests clearance mechanisms involving alveolar macrophages and the mucociliary transport system at the alveolobronchial clearance pathway. At low SO2 or NOx exposures enhanced particle clearance was observed. Lung clearance was depressed at 15 and 24 ppm of NO2 after 22 exposures as well as at 20 ppm of SO2 after 11 exposures, and also at 1 ppm of SO2 after 25 exposures. Dose-response curves for the SO2 and NOx exposures showed differences explainable by the routes by which these gases reach the alveolar macrophages.

Plasma Volume Expansion Resulting from Intravenous Glucose Tolerance Test

Directory of Open Access Journals (Sweden)

Robert G. Hahn

2011-01-01

Full Text Available Objective. To quantify the degree of plasma volume expansion that occurs during an intravenous glucose tolerance test (IVGTT. Methods. Twenty healthy volunteers (mean age, 28 years underwent IVGTTs in which 0.3 g/kg of glucose 30% was injected as a bolus over 1 min. Twelve blood samples were collected over 75 min. The plasma glucose and blood hemoglobin concentrations were used to calculate the volume distribution (Vd and the clearance (CL of both the exogenous glucose and the injected fluid volume. Results. The IVGTT caused a virtually instant plasma volume expansion of 10%. The half-life of the glucose averaged 15 min and the plasma volume expansion 16 min. Correction of the fluid kinetic model for osmotic effects after injection reduced CL for the infused volume by 85%, which illustrates the strength of osmosis in allocating fluid back to the intracellular fluid space. Simulations indicated that plasma volume expansion can be reduced to 60% by increasing the injection time from 1 to 5 min and reducing the glucose load from 0.3 to 0.2 g/kg. Conclusion. A regular IVGTT induced an acute plasma volume expansion that peaked at 10% despite the fact that only 50–80 mL of fluid were administered.

Automated Real-Time Clearance Analyzer (ARCA), Phase I

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National Aeronautics and Space Administration — The Automated Real-Time Clearance Analyzer (ARCA) addresses the future safety need for Real-Time System-Wide Safety Assurance (RSSA) in aviation and progressively...

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2010-07-06

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2010-12-22

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[Medical clearance for missions abroad (EEU): definitions, recommendations for use and performance].

Science.gov (United States)

Kollaritsch, Herwig; Wenisch, Christoph; Hatz, Christoph; von Laer, Gunther; Bauer, Bernd; Hollenstein, Ursula; Haditsch, Martin; Diridl, Gerhard; Malinowski, Waldemar; Jeschko, Eva; Payer-Neundlinger, Gabriela; Speiser-Remp, Nicole; Pichler, Hannes E T; Rumpold, Helmut; Stemberger, Heinrich; Eder, Gerald; Wiedermann, Gerhard; Wiedermann, Ursula

2007-01-01

Standards for medical clearance for private or business missions abroad are--at least in the German speaking countries--not clearly defined and mostly derived from the old terminus "Tropentauglichkeit" which means fit for mission in the tropics. The authors now define a new standard, called "Entsendungstauglichkeitsuntersuchung" which means clearance of fitness for all types of missions abroad, independent of distinct climatic zones. To meet the inhomogenous requirements of different institutions and different types of missions the medical examination proposed follows a modular structure to optimize economic and medical use of resources. Moreover, as Austria, Germany and Switzerland have different legal and economic postulates, the medical examination has to be adapted to the different premises. The definition and description of this special type of "medical clearance for missions abroad" is supplemented by recommendations for definitions of clients who should undergo such an investigation and the professionals who should perform this type of investigation. Additionally, results of this type of medical clearance are defined and prophylactic aspects in terms of pre-travel advice are mentioned.

Adalimumab Dose Tapering in Psoriasis: Predictive Factors for Maintenance of Complete Clearance.

Science.gov (United States)

Hansel, Katharina; Bianchi, Leonardo; Lanza, Francesco; Bini, Vittorio; Stingeni, Luca

2017-03-10

Psoriasis can be managed successfully with long-term biologics. Real-life clinical practice may require dose tapering as a therapeutic option to reduce the risk of drug-exposure and to increase cost-effectiveness. The responsiveness to extended intervals between adalimumab doses and the possible predictive factors of maintenance of complete clearance were studied in a retrospective 7-year single-centre analysis. Thirty patients who achieved complete clearance with adalimumab underwent dose tapering, progressively extending between-dose intervals (to 21-28 days). Sixty percent of subjects (group A) maintained complete clearance, whereas 40.0% (group B) relapsed and were switched back to the standard dosage to re-achieve complete clearance. Body mass index (BMI) and time to achieve Psoriasis Area Severity Index (PASI-100) with adalimumab standard treatment before dose tapering were significantly lower in group A than in group B (multi-variate Cox regression: p < 0.05, Kaplan-Meier analysis: p < 0.001, respectively). This study suggests that patients with lower BMI and shorter time to achieve PASI-100 with adalimumab standard dose were significantly more likely to be candidates for dose tapering.

Turbine blade tip clearance measurement using a skewed dual-beam fiber optic sensor

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Ye, De-chao; Duan, Fa-jie; Guo, Hao-tian; Li, Yangzong; Wang, Kai

2012-08-01

Optimization and active control of the tip clearance of turbine blades has been identified as a key to improve fuel efficiency, reduce emission, and increase service life of the engine. However, reliable and real-time tip clearance measurement is difficult due to the adverse environmental conditions that are typically found in a turbine. We describe a dual-beam fiber optic measurement system that can measure the tip timing and tip clearance simultaneously. Because the tip timing information is used to calculate the tip clearance, the method is insensitive to the signal intensity variation caused by fluctuations in environmental conditions such as light source instability, contamination, and blade tip imperfection. The system was calibrated and tested using experimental rotors. The test results indicated a high resolution of 4.5 μm and measurement accuracy of ±20 μm over the rotation speed range of 2000 to 10,000 rpm.

Radioactive clearance discharge of effluent from nuclear and radiation facilities

International Nuclear Information System (INIS)

Liu Xinhua; Xu Chunyan

2013-01-01

On the basis of the basic concepts of radiation safety management system exemption, exclusion and clearance, we expound that the general industrial gaseous and liquid effluent discharges are exempted or excluded, gaseous and liquid effluent discharged from nuclear and radiation facilities are clearance, and non-radioactive. The main purpose of this paper is to clarify the concepts, reach a consensus that the gaseous and liquid effluent discharged from nuclear and radiation facilities are non-radioactive and have no hazard to human health and natural environment. (authors)

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

International Nuclear Information System (INIS)

Qadri, S. S. U.; Khalid, S. E.; Mahmud, S. M.

2014-01-01

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)

Development of a Novel System to Measure a Clearance of a Passenger Platform

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Shimizu, M.; Oizumi, J.; Matsuoka, R.; Takeda, H.; Okukura, H.; Ooya, A.; Koike, A.

2016-06-01

Clearances of a passenger platform at a railway station should be appropriately maintained for safety of both trains and passengers. In most Japanese railways clearances between a platform and a train car is measured precisely once or twice a year. Because current measurement systems operate on a track, the closure of the track is unavoidable. Since the procedure of the closure of a track is time-consuming and bothersome, we decided to develop a new system to measure clearances without the closure of a track. A new system is required to work on a platform and the required measurement accuracy is less than several millimetres. We have adopted a 3D laser scanner and stop-and-go operation for a new system. The current systems on a track measure clearances continuously at walking speed, while our system on a platform measures clearances at approximately ten metres intervals. The scanner controlled by a PC acquires a set of point data at each measuring station. Edge points of the platform, top and side points of two rails are detected from the acquired point data. Finally clearances of the platform are calculated by using the detected feature points of the platform and the rails. The results of an experiment using a prototype of our system show that the measurement accuracy by our system would be satisfactory, but our system would take more time than the current systems. Since our system requires no closure of a track, we conclude that our system would be convenient and effective.

Effects of a Nonuniform Tip Clearance Profile on the Performance and Flow Field in a Centrifugal Compressor

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Yohan Jung

2012-01-01

Full Text Available This paper presents a numerical investigation of the effects of a nonuniform tip clearance profile on the performance and flow field in a centrifugal compressor with a vaneless diffuser. This study focuses in particular on the magnitude and location of the wake. Six impellers with different tip clearance profiles were tested in the flow simulations. The accuracy of the numerical simulations was assessed by comparing the experimental data with the computational results for a system characterized by the original tip clearance. Although the performance improved for low tip clearances, a low tip clearance at the trailing edge improved the compressor performance more significantly than a low tip clearance at the leading edge. The flow field calculated for a system characterized by a low tip clearance at the trailing edge produced a more uniform velocity distribution both in the circumferential and in the axial directions at the impeller exit because the wake magnitude was reduced. As a consequence, this impeller provided a better potential for diffusion processes inside a vaneless diffuser.