Intracellular Fluid Volume Research Articles

Can Physical Therapy Techniques Slow Down the Progression of Lipedema?

Background: Lipedema is a disease characterized by an increase in extracellular fluid. In these patients, the increase in the amount of extracellular fluid may accelerate the progression of the disease. The aim of this study is to examine the effect of complex decongestive therapy (CDT) on intracellular/extracellular fluid balance. Methods and Results: Twenty-two female patients diagnosed with lipedema by a specialist lymphologist were included in the study. Patients were subjected to complex decongestive therapy and pneumatic compression therapy 6 days a week for 1 month. Extracellular and intracellular fluid volumes were assessed using bioimpedance spectroscopy before and after the treatment. A decrease in intracellular (p = 0.010) and extracellular (p = 0.002) fluid volumes was observed after the treatment. Conclusion: There is no completely curative treatment method for lipedema. Current treatments aim to slow down the progression of the disease. CDT is considered effective in reducing intracellular and extracellular fluid volume in lipedema patients. Therefore, it is thought to be effective in slowing down the progression of the disease.

Understanding Hypervolemia in Chronic Kidney Disease

Introduction: Chronic Kidney Disease (CKD) is a progressive and irreversible decline in kidney function and a decreased Glomerular Filtration Rate (GFR). Decreased kidney function contributes to decreased water excretion and fluid overload caused by decreased GFR. A progressive decrease in GFR in renal disease leads to hypertension, sodium retention, and fluid overload. Discussion: CKD is kidney damage or also defined as a decrease in glomerular filtration rate (GFR) of less than 60 ml/minute/1.73m2 that occurs for 3 months or more. CKD is most caused by Diabetes Mellitus 64.1% and Hypertension 80.7%. One clinical manifestation in patients with CKD is an increase in fluid volume (hypervolemia). Hypervolemia is one of the nursing problems in the nursing care process. Based on the Indonesian Nursing Diagnosis Standard Book, hypervolemia is an increase in intravascular, interstitial, and/or intracellular fluid volume. The etiology of hypervolemia in CKD patients is a regulatory mechanism disorder associated with decreased GFR. Signs and symptoms both major and minor in hypervolemia nursing problems show that most patients have peripheral oedema of 53.8%, the prevalence of anemia is 52.3%, the prevalence of Haemoglobin 7-10 mg/dl is 68.3%, and the prevalence of oliguria is 16.3%. One of the actual nursing diagnosis in patients with CKD is hypervolemia related to the disturbance of regulatory mechanisms (a decrease in GFR). A progressive decrease in GFR can lead to sodium and fluid retention which causes fluid balance disturbances.

Superficial zone chondrocytes can get compacted under physiological loading: A multiscale finite element analysis.

Recent in vivo and in vitro studies have demonstrated that superficial zone (SZ) chondrocytes within articular layers of diarthrodial joints die under normal physiologic loading conditions. In order to further explore the implications of this observation in future investigations, we first needed to understand the mechanical environment of SZ chondrocytes that might cause them to die under physiological sliding contact conditions. In this study we performed a multiscale finite element analysis of articular contact to track the temporal evolution of a SZ chondrocyte's interstitial fluid pressure, hydraulic permeability, and volume under physiologic loading conditions. The effect of the pericellular matrix modulus and permeability was parametrically investigated. Results showed that SZ chondrocytes can lose ninety percent of their intracellular fluid after several hours of intermittent or continuous contact loading, resulting in a reduction of intracellular hydraulic permeability by more than three orders of magnitude. These findings are consistent with loss of cell viability due to the impediment of cellular metabolic pathways induced by the loss of fluid. They suggest that there is a simple mechanical explanation for the vulnerability of SZ chondrocytes to sustained physiological loading conditions. Future studies will focus on validating these specific findings experimentally. STATEMENT OF SIGNIFICANCE: As with any mechanical system, normal 'wear and tear' of cartilage tissue lining joints is expected. Yet incidences of osteoarthritis are uncommon in individuals younger than 45. This counter-intuitive observation suggests there must be an intrinsic repair mechanism compensating for this wear and tear over many decades of life. Recent experimental studies have shown superficial zone chondrocytes die under physiologic loading conditions, suggesting that this repair mechanism may involve cell replenishment. To better understand the mechanical environment of these cells, we performed a multiscale computational analysis of articular contact under loading. Results indicated that normal activities like walking or standing can induce significant loss of intracellular fluid volume, potentially hindering metabolic activity and fluid transport properties, and causing cell death.

Part of anti-covid therapy based on a theoretical model describing mechanics of contact interaction between coronavirus and cell membrane

This article proposes a theoretical model of mechanical feedback in pattern formation on deforming a membrane when coronavirus enters a cell. Coronavirus stiff and flexible spike proteins attach to ACE2 receptors on the cell membrane of the target cell. TMPRSS2 triggers the fusion of the viral and cell membranes with the formation of a fusion pore leading to opening of a capsid surrounded by the coronavirus envelope and viral RNA release into the cell. Based on mechanical feedback analysis of contact interaction and elastic shell theory, a critical value of cell radius, at which a fusion pore is formed and membrane damage occurs locally, is determined. The results revealed that the smaller the cell size, the less likely that the cell will be damaged mechanically when exposed to the virus. One of the ways to reduce the cell size is to decrease intracellular fluid volume through the use of medicines - diuretics. The critical value of cell radius is inversely proportional to the value of binding energy at the time of attachment of the coronavirus to the cell membrane. Further research is required to improve our knowledge of the dependency of binding energy on the shape and sizes of spikelike bumps for various types of coronavirus strains. It may be predicted that when a new coronavirus strain will emerge, it may produce lower binding energy to cell surface and the severity of the disease may decrease. It is necessary to verify the conclusions of the theoretical study by experimental methods.

Copeptin adaptive response to SGLT2 inhibitors in patients with type 2 diabetes mellitus: The GliRACo study.

In type 2 diabetes mellitus (T2DM), the antidiuretic system participates in the adaptation to osmotic diuresis further increasing urinary osmolality by reducing the electrolyte-free water clearance. Sodium glucose co-transporter type 2 inhibitors (SGLT2i) emphasize this mechanism, promoting persistent glycosuria and natriuresis, but also induce a greater reduction of interstitial fluids than traditional diuretics. The preservation of osmotic homeostasis is the main task of the antidiuretic system and, in turn, intracellular dehydration the main drive to vasopressin (AVP) secretion. Copeptin is a stable fragment of the AVP precursor co-secreted with AVP in an equimolar amount. To investigate the copeptin adaptive response to SGLT2i, as well as the induced changes in body fluid distribution in T2DM patients. The GliRACo study was a prospective, multicenter, observational research. Twenty-six consecutive adult patients with T2DM were recruited and randomly assigned to empagliflozin or dapagliflozin treatment. Copeptin, plasma renin activity, aldosterone and natriuretic peptides were evaluated at baseline (T0) and then 30 (T30) and 90 days (T90) after SGLT2i starting. Bioelectrical impedance vector analysis (BIVA) and ambulatory blood pressure monitoring were performed at T0 and T90. Among endocrine biomarkers, only copeptin increased at T30, showing subsequent stability (7.5 pmol/L at T0, 9.8 pmol/L at T30, 9.5 pmol/L at T90; p = 0.001). BIVA recorded an overall tendency to dehydration at T90 with a stable proportion between extra- and intracellular fluid volumes. Twelve patients (46.1%) had a BIVA overhydration pattern at baseline and 7 of them (58.3%) resolved this condition at T90. Total body water content, extra and intracellular fluid changes were significantly affected by the underlying overhydration condition (p < 0.001), while copeptin did not. In patients with T2DM, SGLT2i promote the release of AVP, thus compensating for persistent osmotic diuresis. This mainly occurs because of a proportional dehydration process between intra and extracellular fluid (i.e., intracellular dehydration rather than extracellular dehydration). The extent of fluid reduction, but not the copeptin response, is affected by the patient's baseline volume conditions. Clinicaltrials.gov, identifier NCT03917758.

The kinetics of isotonic and hypertonic resuscitation fluids is dependent on the sizes of the body fluid volumes.

The extracellular and intracellular fluid volumes (ECV and ICV) vary not only with age, gender, and body weight but also with the habitual intake of water. The present study examines whether the baseline variations in the ECV and ICV change the distribution and elimination of subsequently given infusion fluids. Twenty healthy male volunteers underwent 50 infusion experiments with crystalloid fluid for which the fluid volume kinetics was calculated based on frequent measurements of the hemodilution using mixed-effects modeling software. The results were compared with the ECV and ICV measured with multifrequency bioimpedance analysis before each infusion started. The fluids were given over 30 minutes and comprised 25 mL/kg Ringer's acetate (N = 20), Ringer's lactate, 5 mL/kg 7.5% saline, and 3 mL/kg 7.5% saline in 6% dextran 70 (these fluids, N = 10). A large ICV was associated with a small extravascular accumulation of infused fluid, which increased the plasma volume expansion and the urinary excretion. With hypertonic fluid, a large ECV greatly accelerated urinary excretion. The body weight did not serve as a covariate in the kinetic models. Albumin was recruited to the plasma during infusion of both types of fluid. The hypertonic fluids served as diuretics. The infused excess sodium and osmolality were distributed over a 35% larger space than the sum of the ECV and ICV. A large ICV reduced the rate of distribution of Ringer's solution, whereas a large ECV accelerated the excretion of hypertonic saline.

Evaluation of the cellular and extracellular fluid of the body of calves using bio impedancemetry

Currently, non‐invasive animal research methods continue to develop, one of which is bioelectrical impedance analysis to determine the body's water, fat, fat‐free, and cell mass, which reflects the assessment of the body's liquids. The electrical and biological significance of impedance analysis lies in the fact that the measurement of the resistance (impedance) of the body's tissues or fluids changes during exposure to alternating currents of different frequencies and makes it possible to take into account the totality of resistance or the actual difference between two measurements taken in succession. The research object was newborn calves, healthy (G1) and with enteritis (G2), selected according to the principle of analogs, 15 animals in each group. The impedance measurements were studied using the “BICA” device (body impedance composition analyzer). Enteritis in calves is accompanied by a significant loss of electrolytes and free fluid, affecting normal metabolic processes. In this regard, the study of the liquids of the body of healthy and enteritis‐sick calves was the main goal of the research. The first signs of enteritis appeared more often on the second and third days of life. In G2: a decrease in motor activity, hunchback (calves do not lean well on the chest limbs, the head is lowered down) were shown, a decrease in the sucking reflex, retraction of the eyeballs into the orbits, low skin turgor, a red border on the gums under the arcade of the incisors. Feces in sick calves are unformed, watery, gray‐yellow in color, with a pungent, sour odor. On the tenth day of life in calves with enteritis, the total body fluid decreased, and this indicator was 1.5 times lower than in healthy calves (P &lt;0.01). The decrease in the total body fluid volume mainly occurred due to a decrease in the level of intracellular fluid, which in sick animals was 2.8 times lower than in healthy animals (p &lt;0.001). At the same time, the level of extracellular fluid in calves from the G1 and the G2 did not differ significantly and amounted to 7.9 ± 0.8% and 6.28 ± 1.0%, respectively. After the treatment (diet therapy and enroxil 5%, intramuscularly, at a dose of 1 ml per 20 kg of body weight once a day for 3 days) by the age of twenty days, the volume of total body fluid in calves with enteritis recovered and did not significantly differ from the level in healthy animals. There were no significant differences in the volume of extracellular fluid in the calves of both groups. However, as for the intracellular fluid volume, this indicator in recovered calves was still significantly lower (P &lt;0.05) than in healthy animals and amounted to 12.14 ± 1.0% and 15.48 ± 0, 7% respectively. Thus, from the data obtained, it can be seen that fluid loss occurs mainly due to the intracellular fluid with enteritis in calves. Complete recovery of the liquid sectors in calves was observed only by the age of one month.

Tolvaptan Reduces Extracellular Fluid per Amount of Body Fluid Reduction Less Markedly than Conventional Diuretics.

Objective Tolvaptan, a vasopressin V2 receptor antagonist, is a water diuretic, removing electrolyte-free water from the kidneys and affecting the water balance between the intracellular and extracellular fluid. We previously reported that tolvaptan efficiently reduced the intracellular fluid volume, suggesting its utility for treating cellular edema. Furthermore, tolvaptan is known for its low incidence of worsening the renal function, with conventional diuretics use associated with worsening of the renal function Methods In this retrospective observational study, five chronic kidney disease (CKD) patients with fluid retention were assessed by the bioelectrical impedance (BIA) method twice (before and after tolvaptan therapy). Tolvaptan was used with conventional diuretics. The post/pre ratio of extracellular water (ECW)/total body water (TBW) in the tolvaptan group was compared with that in 18 CKD patients undergoing body fluid reduction with conventional diuretics alone (conventional diuretics groups), taking the reduced amount of body fluid into consideration. Results Removing body fluid, either by tolvaptan or by conventional diuretics alone, decreased the ECW/TBW ratio. Of note, the reduction in extracellular fluid was milder in the tolvaptan group than in the conventional diuretics group. Conclusion Tolvaptan reduces the extracellular fluid per amount of body fluid reduction less markedly than conventional diuretics.

Impact of the nature of the capillary wall on plasma refilling during hemodialysis.

Our aim was to clarify the impact of the nature of the capillary wall, defined by the contribution of large (LP), small (SP), and ultrasmall (UP) pores, on plasma refilling in a hemodialysis session. This study included data from 78 patients. The relative blood volume change (ΔBV%) was monitored using a Crit-Line monitor. A bioimpedance device was used to measure extracellular and intracellular fluid volumes, and the excess fluid mass (MExF) was calculated. We simulated blood volume change (sΔBV%) based on a three-pore model. Hydraulic permeability of the capillary wall (LpS) and fractional contribution of LP to LpS (αLP) were determined by fitting sΔBV to ΔBV. The total refilling volume (TVref) was calculated from the total ultrafiltration volume and total blood volume change. Values were standardized to a body surface area of 1.73 m2 and are denoted by the subscript BSA. LpS and αLP were 3.09 (2.32, 4.68) mL/mmHg/min and 0.069 (0.023, 0.109), respectively. The standardized regression coefficient (β) of the ultrafiltration rate (UFRBSA) and initial excess fluid mass (MExF,BSA,0) by multiple linear regression analysis of TVref,BSA without (Model 1) and with (Model 2) αLP were as follows: UFRBSA, 0.714/<0.001 (β/p); MExF,BSA,0, 0.247/<0.001 (Model 1); UFRBSA, 0.799/<0.001; MExF,BSA,0, 0.066/0.237; and αLP, -0.327/<0.001 (Model 2). The impact of volume overload (MExF,BSA,0) on plasma refilling became insignificant with the addition of αLP in the model, suggesting that the nature of the capillary wall described by inter-endothelial gaps (LP) may have a greater impact on plasma refilling than volume overload.

Delirium in Acute Poisoning with 1,4-Butanediol and Its Correction

Delirium complicating regular use of psychoactive substances remains one of the major issues of critical care, toxicology, and psychiatry. However, the pathogenetic mechanisms of delirium development in patients with 1,4-butanediol poisoning have been poorly studied until now.The aim of the study was to reveal specific patterns of delirium in patients with 1,4-butanediol poisoning as well as to study the changes in systemic hemodynamic parameters, respiratory function, and body fluid compartments during the treatment.Material and methods. The study was prospective and treatment-randomized. Forty-eight male patients aged 20 to 45 years with delirium and acute 1,4-butanediol poisoning were enrolled. Of them, 24 patients were administered with succinate-containing drug 40 ml daily, 24 patients received standard treatment without antihypoxic agents. We studied the evolution of delirium, changes in anaerobic metabolism parameters, systemic hemodynamics, respiratory function, and the volume of fluid compartments. Impedance measurement method adjusted for interference was used in the study.Results. At the «peak» of delirium (days 1–3), the hyperdynamic circulation, increased systemic arterial tone, stroke output, respiratory function parameters, and metabolic lactate acidosis were recorded. A decrease in total fluid volume and extracellular fluid volume was clearly observed during day 1 of intoxication delirium along with increased permeability of cell membranes. On day 3 of delirium, a decrease in intracellular fluid volume and increase in extracellular fluid volume were noted. After the cytoflavin administration, shorter delirium duration (7.5 [6; 8] days), more rapid correction of lactate acidosis, stabilization of respiratory parameters and stabilization of cell membrane permeability by day 5 were found. In the control group, delirium persisted for up to 14 [11; 15] days (z=-5.9; P=0.00011) with more frequent development of complications such as nosocomial pneumonia (χ2=8.4, P&lt;0.001).Conclusion. The severity of delirium in acute poisoning with 1,4-butanediol was associated with metabolic lactate acidosis, changes in systemic hemodynamics and pulmonary function. A positive effect of adjunctive antihypoxic therapy with succinate-containing agent on cardio-respiratory parameters, cell membrane permeability, water balance due to elimination of tissue hypoxia and prompt switching to tissue aerobic metabolism has been found.

Perturbed body fluid distribution and osmoregulation in response to high salt intake in patients with hereditary multiple exostoses

SummaryBackgroundHereditary Multiple Exostoses (HME) is a rare autosomal disorder characterized by the presence of multiple exostoses (osteochondromas) caused by a heterozygous loss of function mutation in EXT1 or EXT2; genes involved in heparan sulfate (HS) chain elongation. Considering that HS and other glycosaminoglycans play an important role in sodium and water homeostasis, we hypothesized that HME patients have perturbed whole body volume regulation and osmolality in response to high sodium conditions.MethodsWe performed a randomized cross-over study in 7 male HME patients and 12 healthy controls, matched for age, BMI, blood pressure and renal function. All subjects followed both an 8-day low sodium diet (LSD, <50 mmol/d) and high sodium diet (HSD, >200 mmol/d) in randomized order. After each diet, blood and urine samples were collected. Body fluid compartment measurements were performed by using the distribution curve of iohexol and 125I-albumin.ResultsIn HME patients, HSD resulted in significant increase of intracellular fluid volume (ICFV) (1.2 L, p = 0.01). In this group, solute-mediated water clearance was significantly lower after HSD, and no changes in interstitial fluid volume (IFV), plasma sodium, and effective osmolality were observed. In healthy controls, HSD did not influence ICFV, but expanded IFV (1.8 L, p = 0.058) and increased plasma sodium and effective osmolality.ConclusionHME patients show altered body fluid distribution and osmoregulation after HSD compared to controls. Our results might indicate reduced interstitial sodium accumulation capacity in HME, leading to ICFV increase. Therefore, this study provides additional support that HS is crucial for maintaining constancy of the internal environment.

MO656CORRELATION BETWEEN CHANGES IN THE BODY FLUID VOLUME CALCULATED BY THE URIC ACID KINETIC MODEL AND CHANGES IN THE BODY WEIGHT*

Abstract Background and Aims Uric acid (UA) is a solute unable to cross the cell membranes in general tissues by any of simple diffusion, facilitated diffusion or active transport. These facts imply that UA distribution volume (UDiV) equals to the extracellular fluid volume (ECFV). We have developed a method for calculating UDiV from serum uric acid levels before and after hemodialysis based on a uric acid kinetic model (Shinzato T, Int J Artif Organs 2020). Urea is evenly distributed throughout the body fluids. Therefore, the total body fluid volume (TBFV) can be calculated by using the same method as the calculation of UDiV for the serum urea level. The remaining body fluid volume, which is TBFV minus UDiV, is considered to reflect the intracellular fluid volume (ICFV). In this study, we clarified the relationship between the amount of change over time in UDiV and ICFV calculated by the uric acid kinetic model and the amount of change over time in the actual body weight of hemodialysis patients. Method Subjects were 1,101 patients with chronic maintenance hemodialysis. UDiV and ICFV before and after dialysis were calculated for two time points, December 2019 and June 2020. Results The amount of change in UDiV per body during the dialysis session showed a very good correlation with the amount of body weight change during the same dialysis (UDiV change = 0.950 x body weight change - 0.158, R-square 0.90, p &amp;lt; 0.0001). The amount of change in ICFV during the 6 months from December 2019 to June 2020 showed a good correlation with the amount of change in post-dialysis body weight during the same period (ICFV change = 0.270 x post-dialysis body weight change + 0. 240, R-square 0.21, p &amp;lt;0.0001). Conclusion These results suggest that the body fluid volume calculated by the uric acid kinetic model has high accuracy.

A dual-fluorophore sensor approach for ratiometric fluorescence imaging of potassium in living cells.

Potassium is the most abundant intracellular metal in the body, playing vital roles in regulating intracellular fluid volume, nutrient transport, and cell-to-cell communication through nerve and muscle contraction. On the other hand, aberrant alterations in K+ homeostasis contribute to a diverse array of diseases spanning cardiovascular and neurological disorders to diabetes to kidney disease to cancer. There is an unmet need for studies of K+ physiology and pathology owing to the large differences in intracellular versus extracellular K+ concentrations ([K+]intra = 150 mM, [K+]extra = 3–5 mM). With a relative dearth of methods to reliably measure dynamic changes in intracellular K+ in biological specimens that meet the dual challenges of low affinity and high selectivity for K+, particularly over Na+, currently available fluorescent K+ sensors are largely optimized with high-affinity receptors that are more amenable for extracellular K+ detection. We report the design, synthesis, and biological evaluation of Ratiometric Potassium Sensor 1 (RPS-1), a dual-fluorophore sensor that enables ratiometric fluorescence imaging of intracellular potassium in living systems. RPS-1 links a potassium-responsive fluorescent sensor fragment (PS525) with a low-affinity, high-selectivity crown ether receptor for K+ to a potassium-insensitive reference fluorophore (Coumarin 343) as an internal calibration standard through ester bonds. Upon intracellular delivery, esterase-directed cleavage splits these two dyes into separate fragments to enable ratiometric detection of K+. RPS-1 responds to K+ in aqueous buffer with high selectivity over competing metal ions and is sensitive to potassium ions at steady-state intracellular levels and can respond to decreases or increases from that basal set point. Moreover, RPS-1 was applied for comparative screening of K+ pools across a panel of different cancer cell lines, revealing elevations in basal intracellular K+ in metastatic breast cancer cell lines vs. normal breast cells. This work provides a unique chemical tool for the study of intracellular potassium dynamics and a starting point for the design of other ratiometric fluorescent sensors based on two-fluorophore approaches that do not rely on FRET or related energy transfer designs.

Low serum sodium concentrations in patients with obesity normalizes with weight loss.

Obesity is associated with higher extracellular fluid (ECF) compared to intracellular fluid (ICF) volume and this dysregulation is associated with hypertension and abdominal obesity, associated with metabolic syndrome. As sodium is predominantly an extracellular cation, a higher ECF/ICF ratio will lower serum sodium concentration. The aim of the study was to see whether weight loss, due to dieting and bariatric surgery, had any impact on serum sodium concentrations in patients with severe obesity. Patients with a BMI ≥35kg/m2 admitted for bariatric surgery at Innlandet Hospital Trust, Norway during 2012-14 were included in the study (n=119). Clinical data and blood samples were recorded at inclusion, after mean six months of dieting, as well as six and 12 months after bariatric surgery. At inclusion, mean serum sodium was in the lower normal range, 138.3 (SD 2.4) mmol/L, but increased to 141.8 (SD 1.9) mmol/L after weight loss. The increase was significantly correlated to total weight loss (rho: 0.29, p=0.007). Twelve months after surgery, serum sodium was significantly higher in patients with a normal BMI (<25kg/m2) compared to patients with overweight. Obesity and hypertension are associated with body fluid dysregulation affecting serum sodium concentrations. As mild hyponatremia, even within the normal sodium range, is associated with increased total mortality and major cardiovascular disease events, serum sodium might be a potential risk marker in patients with obesity.

In Pursuit of Designing Multicellular Engineered Living Systems: A Fluid Mechanical Perspective

From intracellular protein signaling to embryonic symmetry-breaking, fluid transport ubiquitously drives biological events in living systems. We provide an overview of the fundamental fluid mechanics and transport phenomena across a range of length scales in cellular systems, with emphasis on how cellular functions are influenced by fluid transport. We also highlight how understanding the physical basis of these fluid dynamic phenomena can be implemented to engineer increasingly complex multicellular systems that recapitulate tissue-level functions. Examples discussed include the manipulation of intracellular fluid volume to achieve cell differentiation/dedifferentiation and the use of microfluidic systems to control the spatial and temporal distribution of morphogens and fluid forces to generate vascularized organoids.

Influence of electrolyte balance on the prognosis of long-term cardiovascular events after acute coronary syndrome

Aim. To assess the effect of electrolyte changes on the prognosis of long-term cardiovascular events after acute coronary syndrome (ACS).Material and methods. The study included 105 patients with ACS who underwent coronary angiography (CA) with coronary stenting. At the study inclusion (before CA with coronary stenting), we collected data on traditional risk factors, analyzed levels of urinary sodium and potassium, kaliuresis and natriuresis. Free water clearance (FWC) and electrolyte free water clearance (EFWC), as well as fluid balance using bioelectrical impedance analysis were determined. Study endpoints (fatal and nonfatal cardiovascular events) were determined 6,2±0,2 months after CA with coronary stenting.Results. It was found that a decrease in urinary sodium (χ2=5,64, p=0,02, Constanta B0 =-0,62, Estimate =-16,5) and natriuresis (χ2=4,1, р=0,044, Constanta B0 =-1,38, Estimate =-5,2) increase the death risk. Urinary sodium of 0,2 mol/L and natriuresis of 0,5 mol are threshold levels of increased risk of death. Urinary potassium decrease was associated with an increase in death risk (threshold level — 0,5 mol/L, χ2=4,99, р=0,025, Constanta B0 =-0,63, Estimate =-70,4) and acute myocardial infarction (threshold level — 0,06 mol/L, χ2=3,93, р=0,04, Constanta B0 =-0,99, Estimate =-58,0) in the long-term period. Increase in EFWC increased the likelihood of long-term transient ischemic attack after ACS (χ2=4,61, р=0,03, Constanta B0 =-2,95, Estimate =-1,0). There were no significant relationships in the matter of FWC (p&gt;0,05). However, with a decrease in intracellular fluid volume compared to normal values and a decrease in FWC or an increase in EFWC, the likelihood of longterm composite endpoints after ACS increases.Conclusion. As a result of the study, risk markers for long-term fatal and non-fatal cardiovascular events after ACS were established: decrease in urinary sodium &lt;0,2 mol/l and potassium &lt;0,5 mol/l; decrease in FWC and increase in EFWC with or without cellular dehydration. The established markers can complement the current cardiovascular risk score methods in patients with ACS.

P1401THE REMOVAL EFFICIENCY OF PHOSPHATE FROM INTRACELLULAR FLUID DURING HEMODIALYSIS

Abstract Background and Aims In hemodialysis (HD) patients without residual renal function, almost all of phosphate (P) absorbed through intestine is eliminated with HD. To avoid hyperphosphatemia, which is major risk for mortality in HD patients, reduced P absorption and /or improved P removal efficiency should be required. The P elimination during HD from intracellular fluid (ICF) remarkably differs from that from extracellular fluid (ECF). Because the total P removal is too complicate to analyze, few studies about P removal efficiency have been performed. In this study, we tried to separately estimate the amount of P removal from ICF and ECF. Method Fifty-eight patients undergoing 4-hour HD with BMI 22±3 were enrolled this study. ECF and ICF volumes were considered respectively as 20% and 40% of body weight (BW). The amount of urea nitrogen (UN) removal (Run) was calculated using the values of serum UN concentration (UN0, UN4) and total body fluid (60% of BW) at pre and post HD as 0.6(UN0 x pre BW – UN4 x post BW). The amount of intradialytic total P removal (Rp) was calculated using the formula previously reported. At starting phase of HD, P is considered to be removed only from ECF, and from ECF and ICF at later stage. In initial hours, when P is removed only from ECF, serum P concentration change exponentially (P = KptP0) as serum UN concentration (UN = KuntUN0). (Where, Kun and Kp are exponential coefficient of UN and P respectively, t is time (min), P0 is serum P concentration before HD). If P outflow from ICF is disregarded, the exponential change in P persists, and serum P concentration at the end of 4-hour HD is Kp240P0. Consequently, the amount of P removal from ECF (Rp(ex)) was calculated as 0.2(P0 x preBW - Kp240P0 x postBW). The exponential coefficient in P change was reported to be 0.997788 times of that in UN. The amount of P removal from ICF (Rp(in)) was calculated as difference between Rp and Rp(ex). Each removal efficiency was calculate as Run/UN0, Rp(ex)/P0 or Rp(in)/P0. Intradialytic removal of P from ECF and ICF were compared with that of UN. Regression analysis was performed on 24 factors which might affect the efficiency. The relationship between drug administration and the removal efficiency was investigated as for 22 drugs. Results UN removal and P removal from ECF were closely related. Run and Rp(ex) had positive correlation (0.564, p&amp;lt;0.001). And Run/UN0 also correlated positively to Rp(ex)/P0 (R=0.970, p&amp;lt;0.001). Rp(ex)/P0 and P0 had a positive correlation (R=0.334, p&amp;lt;0.01) as well as Run/UN0 and UN0 (R=0.382, p&amp;lt;0.01). P removal from ICF showed different pattern. In comparison between P removal from ECF and ICF, removal amount showed positive correlation (R=0.634, p&amp;lt;0.001), but removal efficiency showed no correlation(R=0.006, ns). Notably, Rp(in)/P0 and P0 had negative correlation (R=0.315, p&amp;lt;0.02). Rp(in) accounted for 44.6±6.2% of Rp. On regression analysis concerning the 24 factors, only P0 and its confounding factors showed correlation with Rp(ex), Rp(in), Rp(ex)/P0 or Rp(in)/P0. Rp(ex)/P0 or Rp(in)/P0 were not affected with administration of 22 investigated drugs. To exclude the influence of P0 on Rp(in)/P0, adjusted Rp(in)/P0 (removal efficiency of P from ICF not affected by P0) was calculated. Investigation on iron containing P binders and ion exchange resins revealed each drug groups ameliorated adjusted Rp(in)/P0. Conclusion This is the first report to analyze separately P removal from ECF and ICF during HD. Increased UN removal efficiency results in increased the removal efficiency of P from ECF, but did not improved that from ICF. Rp(in) accounts for about half of Rp. For improving total P removal efficiency, removal efficiency of P from ICF should be increased. Some drugs were suggested to increase removal efficiency of P from ICF.

A noninvasive method to study the evolution of extracellular fluid volume in mice using time-domain nuclear magnetic resonance.

Maintaining water homeostasis is fundamental for cellular function. Many diseases and drugs affect water balance and plasma osmolality. Water homeostasis studies in small animals require the use of invasive or terminal methods that make intracellular fluid volume and extracellular fluid volume (ECF) monitoring over time stressful and time consuming. We examined the feasibility of monitoring mouse ECF by a noninvasive method using time-domain nuclear magnetic resonance (TD-NMR). This technique allows differentiation of protons in a liquid environment (free fluid) from protons in soft tissues containing a majority of either small molecules (lean) or large molecules (fat). Moreover, this apparatus enables rapid, noninvasive, and repeated measurements on the same animal. We assessed the feasibility of coupling TD-NMR analysis to a longitudinal metabolic cage study by monitoring mice daily. We determined the effect of 24-h water deprivation on mouse body parameters and detected a sequential and overlapping decrease in free fluid and lean mass during water deprivation. Finally, we studied the effect of mineralocorticoids that are known to induce a transient increase in ECF but for which no direct measurements have been performed in mice. We showed, for the first time, that mineralocorticoids induced a transient ~15% increase in free fluid in conscious mice. TD-NMR is, therefore, the first method to allow direct measurement of discrete changes in ECF in conscious small animals. This method allows analysis of kinetic changes to stimuli before investigating with terminal methods and will allow further understanding of fluid disorders.

Study on calculation method of internal and external fluid capacity of human cells based on bioimpedance spectroscopy

Bioelectrical impedance measurement technology is a non-invasive detection technology for extracting human physiological and pathological information. The analysis method of the relationship between bioimpedance and human physiological parameters is an important part of this technology. In order to calculate the internal and external liquid volume of human cells more accurately, based on the Moissl equation for calculating the internal and external fluid volume of human cells, a segmented human bioimpedance spectrum measurement model and an improved calculation method of intracellular and external fluid capacity were proposed. The measurement and calculation experiments of the intracellular and extracellular fluid volume before and after the human body's water intake were designed and compared with the Moissl calculation method. The results show that the improved calculation method can calculate the intracellular and extracellular fluid volumes more effectively, and the relative error is less than 5%, which may provide new ideas or more accurate methods for the analysis of human body components, facilitating the diagnosis and treatment of diseases.

Monitoring thoracic fluid content using bioelectrical impedance spectroscopy and Cole modeling

Abstract Heart failure is a chronic disease marked by frequent hospitalizations due to pulmonary fluid congestion. Monitoring the thoracic fluid status may favor the detection of fluid congestion in an early stage and enable targeted preventive measures. Bioelectrical impedance spectroscopy (BIS) has been used in combination with the Cole model for monitoring body composition including fluid status. The model parameters reflect intracellular and extracellular fluid volume as well as cell sizes, types and interactions. Transthoracic BIS may be a suitable approach to monitoring variations in thoracic fluid content.