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David A Bushinsky - One of the best experts on this subject based on the ideXlab platform.
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contribution of intestine bone kidney and dialysis to Extracellular Fluid calcium content
Clinical Journal of The American Society of Nephrology, 2010Co-Authors: David A BushinskyAbstract:Calcium (Ca) balance is the net of Ca intake and output from the body over a period of time. The concept of Ca balance does not consider the redistribution of Ca that often occurs in patients with chronic kidney disease (CKD), especially those who are on dialysis, which is often in the form of soft tissue and/or vascular calcification. In this article, we consider movement of Ca with respect to the Extracellular Fluid (ECF) and develop a mathematical formulation for Ca homeostasis with respect to the ECF that includes input and output from the diet, the bone, the kidney, and dialysis. We consider calcium homeostasis in healthy individuals and in patients with excess parathyroid hormone, excess 1,25-dihydroxyvitamin D(3), and metabolic acidosis; patients who have CKD and are not on dialysis; and, finally, patients who have CKD and are on dialysis. On the basis of a number of assumptions, dialysis patients with a daily intake of >37.5 mmol of elemental Ca (1.5 g) have movement of Ca into the ECF even without supplemental activated vitamin D. Addition of activated vitamin D, which increases intestinal Ca absorption and can increase resorption of Ca from bone, leads to the movement of Ca into the ECF at virtually all levels of intake; however, there are numerous unanswered questions regarding Ca homeostasis in patients with CKD, including how much of the Ca, administered as a phosphate binder, is absorbed and what is the fate of this absorbed Ca. Until these pressing questions are answered with well-designed experiments, we do not know whether we are doing more harm than good for our dialysis patients by administering additional Ca as a phosphate binder, especially when they also receive activated vitamin D.
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contribution of intestine bone kidney and dialysis to Extracellular Fluid calcium content
Clinical Journal of The American Society of Nephrology, 2010Co-Authors: David A BushinskyAbstract:Calcium (Ca) balance is the net of Ca intake and output from the body over a period of time. The concept of Ca balance does not consider the redistribution of Ca that often occurs in patients with chronic kidney disease (CKD), especially those who are on dialysis, which is often in the form of soft tissue and/or vascular calcification. In this article, we consider movement of Ca with respect to the Extracellular Fluid (ECF) and develop a mathematical formulation for Ca homeostasis with respect to the ECF that includes input and output from the diet, the bone, the kidney, and dialysis. We consider calcium homeostasis in healthy individuals and in patients with excess parathyroid hormone, excess 1,25-dihydroxyvitamin D3, and metabolic acidosis; patients who have CKD and are not on dialysis; and, finally, patients who have CKD and are on dialysis. On the basis of a number of assumptions, dialysis patients with a daily intake of >37.5 mmol of elemental Ca (1.5 g) have movement of Ca into the ECF even without supplemental activated vitamin D. Addition of activated vitamin D, which increases intestinal Ca absorption and can increase resorption of Ca from bone, leads to the movement of Ca into the ECF at virtually all levels of intake; however, there are numerous unanswered questions regarding Ca homeostasis in patients with CKD, including how much of the Ca, administered as a phosphate binder, is absorbed and what is the fate of this absorbed Ca. Until these pressing questions are answered with well-designed experiments, we do not know whether we are doing more harm than good for our dialysis patients by administering additional Ca as a phosphate binder, especially when they also receive activated vitamin D.
Michael A Peters - One of the best experts on this subject based on the ideXlab platform.
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new gender specific formulae for estimating Extracellular Fluid volume from height and weight in adults
Nuclear Medicine Communications, 2021Co-Authors: N J Bird, Michael A PetersAbstract:Aims First, to derive gender-specific formulae for estimation of Extracellular Fluid volume (eECV) and second, compare eECV as a scaling metric for slope-intercept glomerular filtration rate (GFR) with estimated body surface area (eBSA), lean body mass (eLBM) and total body water (eTBW). Methods GFR and 'slope-only' GFR (GFR/ECV), both single compartment-corrected, were measured in a previously published multicentre database of healthy potential kidney transplant donors. Measured ECV (mECV) was obtained as ratio GFR-to-GFR/ECV. Formulae for eECV in men and women were derived from the relationship of mECV with height and weight and expressed as eECV = a.weight.height. In a population of prospective kidney transplant donors from a single centre, eECV was compared with mECV. GFR was scaled to eECV, eBSA, eLBM and eTBW, estimated from previously published formulae. Results In men and women, respectively, a was 0.0755 and 0.0399, x was 0.6185 and 0.6065 and y was 0.4982 and 0.6217. In the single centre, biases (±precisions) of eECV against mECV in men and women were 0.26 (±1.68) and 0.31 (±1.67) l. Mean GFR/eBSA was higher in men but mean GFR/eLBM and GFR/eTBW were higher in women. Mean GFR/ECV and mean GFR/eECV were very similar between the two genders. GFR/ECV and GFR/eECV showed correlations with each other that were almost identical between men and women. Conclusions New formulae are described for estimating eECV. Scaling GFR to eECV is more physiological than scaling to eBSA and accounts for gender. eECV used for measuring GFR from a single blood sample should be gender-specific.
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higher Extracellular Fluid volume in women is concealed by scaling to body surface area
Scandinavian Journal of Clinical & Laboratory Investigation, 2013Co-Authors: Michael A Peters, Nagabhushan Seshadri, Mark D J Neilly, Laura Perry, Claire A Hooker, Bethany Howard, Ravin Sobnack, Andrew Irwin, Surendra Dave, Hayley SnellingAbstract:AbstractObjective. The objective was to assess body surface area (BSA) for scaling Extracellular Fluid volume (ECV) in comparison with estimated lean body mass (LBM) and total body water (TBW) across a range of body mass indices (BMI). Methods. This was a multi-centre study from 15 centres that submitted raw data from routine measurement of GFR in potential kidney transplant donors. There were 819 men and 1059 women in total. ECV was calculated from slope-intercept and slope-only measurements of GFR. ECV was scaled using two methods: Firstly, division of ECV by the scaling variable (ratio method), and secondly the regression method of Turner and Reilly. Subjects were placed into five BMI groups: < 20, 20–24.9, 25–29.9, 30–34.9, and 35 + kg/m2. LBM and TBW were estimated from previously published, gender-specific prediction equations. Results. Ratio and regression scaling gave almost identical results. ECV scaled to BSA by either method was higher in men in all BMI groups but ECV scaled to LBM and TBW was ...
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Extracellular Fluid volume and glomerular filtration rate in 1878 healthy potential renal transplant donors effects of age gender obesity and scaling
Nephrology Dialysis Transplantation, 2012Co-Authors: Michael A Peters, Hayley Snelling, Nagabhushan Seshadri, Mark D J Neilly, Laura Perry, Claire A Hooker, Bethany Howard, Ravin Sobnack, Andrew Irwin, Thomas GruningAbstract:Aim. The aim of this study was to investigate the influence of age, gender, obesity and scaling on glomerular filtration rate (GFR) and Extracellular Fluid volume (ECV) in healthy subjects. Methods. This is a retrospective multi-centre study of 1878 healthy prospective kidney transplant donors (819 men) from 15 centres. Age and body mass index (BMI) were not significantly different between men and women. Slope-intercept GFR was measured (using Cr-51-EDTA in 14 centres; Tc-99m-DTPA in one) and scaled to body surface area (BSA) and lean body mass (LBM), both estimated from height and weight. GFR was also expressed as the slope rate constant, with one-compartment correction (GFR/ECV). ECV was measured as the ratio, GFR to GFR/ECV. Results. ECV was age independent but GFR declined with age, at a significantly faster rate in women than men. GFR/BSA was higher in men but GFR/ECV and GFR/LBM were higher in women. Young women ( 65 years). There was no difference in GFR between obese (BMI > 30 kg/m2) and non-obese men. Obese women, however, had lower GFR than non-obese women and negative correlations were observed between GFR and both BMI and %fat. The decline in GFR with age was no faster in obese versus non-obese subjects. ECV/BSA was higher in men but ECV/LBM was higher in women. ECV/weight was almost gender independent, suggesting that fat-free mass in women contains more Extracellular water. BSA is therefore a misleading scaling variable. Conclusion. There are several significant differences in GFR and ECV between healthy men and women.
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use of body surface area for assessing Extracellular Fluid volume and glomerular filtration rate in obesity
American Journal of Nephrology, 2010Co-Authors: Michael A Peters, Daphne M GlassAbstract:Objective: To examine body surface area (BSA) for scaling Extracellular Fluid volume (ECV) in obesity. ECV varies less than glomerular filtration rate (GFR) in a clinical population
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estimated lean body mass is more appropriate than body surface area for scaling glomerular filtration rate and Extracellular Fluid volume
Nephron Clinical Practice, 2010Co-Authors: Michael A Peters, Daphne M Glass, Hayley Snelling, Shirley Love, N J BirdAbstract:Background/Aims: To compare body surface area (BSA) with lean body mass (LBM) for scaling Extracellular Fluid volume (ECV) and glomerular filtration rate (GFR). Methods:Phase 1: Total body water (TBW), bromide space and LBM were measured with 3H-water, 77Br and dual X-ray absorptiometry, respectively, in 6 healthy adults. Phase 2: ECV and GFR were measured with 51Cr-EDTA in 95 healthy adults and 56 children (0.5–13 years). ECV was calculated as GFR divided by GFR/ECV, both corrected for the one-compartment assumption. LBM was estimated (eLBM) in adults from height and weight and in children using a height/weight formula for estimating ECV and a constant derived from a separate adult population relating ECV to eLBM. Results:Phase 1: LBM and BSA correlated closely with TBW and bromide space. With LBM, the regressions passed through the origin, but with BSA, the intercepts were significantly below zero. Phase 2: GFR/BSA and ECV/BSA were higher in men than women but no difference was recorded in GFR/eLBM, GFR/ECV or ECV/eLBM. ECV showed a linear relation with eLBM and a non-linear relation with BSA. GFR/BSA and ECV/BSA correlated significantly with BSA but neither GFR/eLBM nor ECV/eLBM correlated with eLBM. Conclusion: eLBM is preferable to BSA for scaling GFR and ECV.
Chenhuan Chen - One of the best experts on this subject based on the ideXlab platform.
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the Extracellular Fluid to intracellular Fluid volume ratio is associated with large artery structure and function in hemodialysis patients
American Journal of Kidney Diseases, 2003Co-Authors: Yaoping Lin, Tseilieh Hsu, Philip Yuan Ding, Wuchang Yang, Chenhuan ChenAbstract:Abstract Background: Large-artery derangement is a major risk factor for cardiovascular and all-cause mortality in patients with end-stage renal disease (ESRD). It is not clear how body Fluid distribution affects large-artery structure and function in patients with ESRD. Methods: One hundred fifty-seven hemodialysis (HD) patients (mean age, 55.9 ± 15.1 years; 76 men, 81 women) were enrolled. Influence of the Extracellular Fluid (ECF)—to—intracellular Fluid (ICF) ratio derived from bioimpedance spectroscopy on the structure and function of the common carotid artery (CCA) and aorta was analyzed. One hundred forty-four healthy subjects were examined to obtain normal reference values for body Fluid compartments. Based on ECF-ICF ratio, 2 groups were identified: ECF-ICF ratio in the 95th percentile or less and ECF-ICF ratio greater than the 95th percentile of age- and sex-stratified normal reference values. Results: ECF-ICF ratio was significantly related to CCA diameter ( r 2 = 0.26; P inc ; r 2 = 0.15; P r 2 = 0.10; P r 2 = 0.21; P r 2 = 0.47; P inc ( r 2 = 0.29; P r 2 = 0.51; P r 2 = 0.40; P inc , aPWV, and AGI than their counterparts. Conclusion: ECF-ICF ratio is associated with large-artery structure and function in HD patients. Patients with ESRD with a high ECF-ICF ratio are characterized by significant large-artery derangement.
Michael J Avram - One of the best experts on this subject based on the ideXlab platform.
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modifications of blood volume alter the disposition of markers of blood volume Extracellular Fluid and total body water
Journal of Pharmacology and Experimental Therapeutics, 1999Co-Authors: Tom C Krejcie, Thomas K Henthorn, Claus U Niemann, W B Gentry, C A Shanks, C Endersklein, Michael J AvramAbstract:Recirculatory pharmacokinetic models for indocyanine green (ICG), inulin, and antipyrine describe intravascular mixing and tissue distribution after i.v. administration. These models characterized physiologic marker disposition in four awake, splenectomized dogs while they were normovolemic, volume loaded (15% of estimated blood volume added as a starch solution), and mildly and moderately hypovolemic (15 and 30% of estimated blood volume removed). ICG-determined blood volumes increased 20% during volume loading and decreased 9 and 22% during mild and moderate hypovolemia. Dye (ICG) dilution cardiac output (CO) increased 31% during volume loading and decreased 27 and 38% during mild and moderate hypovolemia. ICG-defined central and fast peripheral intravascular circuits accommodated blood volume alterations and the fast peripheral circuit accommodated blood flow changes. Inulin-defined Extracellular Fluid volume contracted 14 and 21% during hypovolemia. Early inulin disposition changes reflected those of ICG. The ICG and inulin elimination clearances were unaffected by altered blood volume. Neither antipyrine-defined total body water volume nor antipyrine elimination clearance changed with altered blood volume. The fraction of CO not involved in drug distribution had a significant effect on the area under the antipyrine concentration-versus-time relationships (AUC) in the first minutes after drug administration. Hypovolemia increased the fraction of CO represented by nondistributive blood flow and increased the antipyrine AUC up to 60% because nondistributive blood flow did not change, despite decreased CO. Volume loading resulted in a smaller (less than 20%) antipyrine AUC decrease despite increased fast tissue distributive flow because nondistributive flow also increased with increased CO.
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recirculatory pharmacokinetic models of markers of blood Extracellular Fluid and total body water administered concomitantly
Journal of Pharmacology and Experimental Therapeutics, 1996Co-Authors: Tom C Krejcie, Thomas K Henthorn, Claus U Niemann, C Klein, Dhanesh K Gupta, W B Gentry, C A Shanks, Michael J AvramAbstract:Pharmacokinetic models were developed to describe the disposition of markers of Extracellular Fluid (inulin) and total body water (antipyrine) from the moment of injection to incorporate the intravascular mixing component, determined by a marker of intravascular space (indocyanine green, ICG). The simultaneous dispositions of these markers were characterized in four halothane-anesthetized dogs. After injection of ICG, [14C]-inulin, and antipyrine into the right atrium, femoral arterial blood samples were collected every 3 sec for 1 min and less frequently to 20 min for ICG and to 360 min for inulin and antipyrine. ICG and antipyrine concentrations were measured by high-performance liquid chromatography and [14C]-inulin concentrations were measured by liquid scintillation counting. The marker concentration histories were characterized completely by fully identifiable recirculatory compartmental models. Because neither ICG nor inulin distribute beyond intravascular space before recirculation, their first-pass data were modelled simultaneously to improve confidence in central circulation model parameters. This central circulation model included an estimate of cardiac output that was retained in the recirculatory models of all markers. Three tissue compartments were identified for antipyrine, a lipid soluble marker that equilibrates with tissue (including the lung) and estimates total body water and tissue blood flow. The hydrophilic marker, inulin, diffuses into interstitial Fluid so slowly that only two extravascular compartments were identified. These models may be used to determine how cardiac output and its distribution, pulmonary drug uptake, and nondistributive blood flow contribute to variability in patient response to drugs with a rapid onset of effect.
Eun Jung Kim - One of the best experts on this subject based on the ideXlab platform.
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Extracellular Fluid intracellular Fluid volume ratio as a novel risk indicator for all cause mortality and cardiovascular disease in hemodialysis patients
PLOS ONE, 2017Co-Authors: Eun Jung Kim, Myung Jin Choi, Jeoung Hwan Lee, Jang Won Seo, Youngki Lee, Jong Woo Yoon, Hyung Jik Kim, Jung Woo NohAbstract:Background In hemodialysis patients, Fluid overload and malnutrition are accompanied by Extracellular Fluid (ECF) expansion and intracellular Fluid (ICF) depletion, respectively. We investigated the relationship between ECF/ICF ratio (as an integrated marker reflecting both Fluid overload and malnutrition) and survival and cardiovascular disease (CVD) in the context of malnutrition-inflammation-arteriosclerosis (MIA) complex. Methods Seventy-seven patients from a single hemodialysis unit were prospectively enrolled. The ECF/ICF volume was measured by segmental multi-frequency bioimpedance analysis. MIA and volume status were measured by serum albumin, C-reactive protein (CRP), pulse wave velocity (PWV) and plasma B-type natriuretic peptide (BNP), respectively. Results The mean ECF/ICF ratio was 0.56±0.06 and the cut-off value for maximum discrimination of survival was 0.57. Compared with the low ECF/ICF group, the high ECF/ICF group (ratio≥0.57, 42%) had higher all-cause mortality, CVD, CRP, PWV, and BNP, but lower serum albumin. During the 5-year follow-up, 24 all-cause mortality and 38 CVD occurred (18 and 24, respectively, in the high ECF/ICF group versus 6 and 14 respectively in the low ECF/ICF group, P<0.001). In the adjusted Cox analysis, the ECF/ICF ratio nullifies the effects of the MIA and volume status on survival and CVD and was an independent predictor of all-cause mortality and CVD: hazard ratio (95% confidence interval); 1.12 (1.01–1.25) and 1.09 (1.01–1.18) for a 0.01 increase in the ECF/ICF ratio. The degree of malnutrition (albumin), inflammation (CRP), arteriosclerosis (PWV), and Fluid overload (BNP) were correlated well with the ECF/ICF ratio. Conclusions Hemodialysis patients with high ECF/ICF ratio are not only Fluid overloaded, but malnourished and have stiff artery with more inflammation. The ECF/ICF ratio is highly related to the MIA complex, and is a major risk indicator for all-cause mortality and CVD.
