Intracellular Water Volume Research Articles

Impaired mobility and MRI markers of vascular brain injury: Atherosclerosis Risk in Communities and UK Biobank studies

BackgroundVascular brain injury (VBI) may be an under-recognised contributor to mobility impairment. We examined associations between MRI VBI biomarkers and impaired mobility.MethodsWe separately analysed Atherosclerosis Risk in Communities (ARIC) and...

The condition of the fluid compartments by the method of bioimpedancemetry in victims with a blast injury

BACKGROUND. According to the modern standards, in case of an acute blood loss, the pathogenetic provision of fluid therapy is based on the ROSE/D concept. According to this concept, after the initial emergency restoration of circulating blood volume, the fluid compartments should be optimized with further stabilization of the condition.
 OBJECTIVE. To study the fluid compartments in mine-explosive injuries victims.
 MATERIALS AND METHODS. 28 servicemen aged 20 to 51 years (average age 34.6±10.3 years) who were in the intensive care unit (ICU) with mine-explosive injuries of various localization (chest, abdomen, limbs) were examined. The victims were given fluid therapy in a restrictive mode. The condition of fluid compartments was determined by the method of bioimpedance measurement and calculation methods.
 RESULTS. On the first day of ICU stay, the total amount of water in the body exceeded the norm by 3 %. At the same time, the volume of intracellular water was significantly lower than normal by 22 %. On the second day, the total amount of water in the body normalized, but the indicator of intracellular water increased by 9.5 % of the reference.
 CONCLUSIONS. It is shown that despite the restoration of the circulating blood volume, there is an intracellular fluid deficit, which, even in the conditions of the restrictive fluid therapy, is replaced by a slight compensatory intracellular hyperhydration the next day when the intravascular volume of fluid is normalized.

Plasma concentration of prophylactic cefazolin best correlates with lean body mass measured by bioimpedance analysis in lumbar spine surgery: Results of a pilot study

The aim of this study was to determine the association between measures of body composition and the concentration of plasma and paraspinal muscle cefazolin. Secondly, we aimed to confirm the efficacy of our hospital dosing regimen in achieving the minimum inhibitory concentration (MIC) at the surgical site. Patients undergoing posterior-based lumbar spine surgery had body composition analysed using bioimpedance analysis. All received 2 g of cefazolin at anaesthetic induction in line with hospital guidelines. Cefazolin concentration was measured in plasma (30-minites) and muscle (30- and 60-minuites) using high-performance liquid chromatography. 20 patients were recruited (mean age 61.5 years; 12 female). Mean plasma cefazolin concentrations were 34.1 +/− 10.2 mg/L; mean muscle concentrations 44.4 +/− 18.6 mg/kg and 43.8 +/− 20.4 mg/kg at 30- and 60-minutes respectively. Univariate analysis showed significant correlation between plasma cefazolin concentration and lean mass weight, absolute body weight, height, dry lean mass, total water, total body water, extracellular and intracellular water volume. Linear regression analysis showed lean mass weight the best predictor of plasma cefazolin concentration. Muscle cefazolin concentration was dependent on the plasma concentration. Using a MIC of 2 mg/L and 2 mg/kg for Staphylococcus aureus, MIC was achieved in all samples. In summary, plasma cefazolin concentration was best predicted by lean body mass. Further work should consider the influence of body composition on antibiotic delivery in extremes of body mass index. Local hospital guidelines are effective at achieving MIC against S. aureus.

Changes in intracellular water volume after leg lymphedema onset and lymphaticovenular anastomosis as its surgical intervention

ObjectiveTo clarify the changes in the intracellular water (ICW) volume in lymphedema-affected legs after lymphedema onset and its surgical intervention (ie, lymphaticovenular anastomosis [LVA]), we investigated the changes in body water composition using bioelectrical impedance analysis. MethodsThis retrospective case series included 41 women with unilateral secondary leg lymphedema. The volume changes in the ICW and extracellular water (ECW) of the affected leg were measured using an InBody S10 (InBody Co, Ltd) multifrequency bioelectrical impedance analyzer, at both lymphedema onset and 1 year after LVA. ResultsThe volume increase with leg lymphedema onset was comparable between the ECW and ICW (0.59 L vs 0.56 L; 95% confidence interval [CI], −0.02 to 0.06; P = .27), and the increase rate was higher for ECW (35.3% vs 22.1%; 95% CI, 9.3%-17.2%; P < .001). The volume reduction at 1 year after LVA was comparable between ECW and ICW (0.23 L vs 0.27 L; 95% CI, −0.08 to 0.02; P = .20), and the reduction rate was higher for ECW (8.7% vs 7.0%, 95% CI, 0.04%-3.2%; P = .044). The volume difference between ICW and ECW remained constant throughout the six measurements before and after LVA (F[3.01, 120.20] = 1.85; P < .14). ConclusionsLeg LVA reduced ICW in the lymphedematous leg. The onset of leg lymphedema increased ECW and ICW in the affected limb, and LVA decreased both ECW and ICW. The volume change in the affected leg was comparable between ECW and ICW at both lymphedema onset and after LVA. However, the rate of change was higher for ECW. The volume difference between ICW and ECW remained constant. Using bioelectrical impedance analysis, alterations in ICW volume were detected in the legs affected by lymphedema, both after the onset of lymphedema and after LVA intervention.

#4969 AN ADEQUATE HYDRATION MANAGEMENT IMPROVES THE EFFICIENCY OF INTRADIALYTIC PHOSPHATE REMOVAL

Abstract Background and Aims The excess of phosphate (P) is one of the major risk factors for death in patients undergoing hemodialysis (HD). Improving P removal efficiency should ameliorate their prognosis. We previously reported, increased urea nitrogen (UN) removal efficiency results in increased the removal efficiency of P from extracellular fluid (ECF), but did not improve that from intracellular fluid (ICF) (NDT, Vol 35, Sup3, P1401, 2020). We also reported that P removal from ICF accounted for in average about 44% of total intradialytic P removal. For improving total P removal efficiency, removal efficiency of P from ICF should be increased. As P is one of the major osmotic agents in ICF, water outflow from ICF will accompany P outflow. We explored correlation between intracellular P removal and intracellular water (ICW) reduction. And we also sought for the strategy which efficiently derive water from ICF in HD patients in order to increase intracellular P removal. Method Eighty-six patients undergoing 4-hour HD were enrolled this study. ICW, extracellular water (ECW) volume and body fat mass (BFM) in each patient were measured with biochemical impedance analysis method before and after HD session. Total body water (TBW) was calculated by ICW + ECW. The amount of intradialytic P removal from ICF and from ECF in each patient was calculated as previously reported (NDT, Vol 35, Sup3, P1401, 2020). The correlation between the amount of intradialytic P removal from ICF and the amount of ICW reduction was investigated. All patients were divided into three groups according to the amount of ICW reduction as high reduction (HR) group, middle reduction (MR) group and low reduction (LR) group. The amount of P removal from ICF was compared between these groups. ICW volume change (ΔICW%) was calculated as (preICW – postICW)/preICW in each patient. Where preICW = ICW volume at the starting of HD, postICW = ICW volume at the end of HD. Circulating plasma volume change (ΔCPV%) was calculated as (postTP – preTP)/postTP in each patient. Where postTP = serum total protein concentration (TP) at the end of HD, preTP = TP at the end of HD. Lean body mass (LBM) was calculated as BW – BFM. Body weight (BW) change (ΔBW%), LBM change (ΔLBM%) and TBW volume change (ΔTBW%) were calculated in the same way as ΔICW%. To seek factors that effectively reduce ICW, the correlation with ΔICW% in ECW/TBW ratio, ΔCPV%, ΔCPV%/ΔBW% ratio, ΔCPV%/ΔLBM% ratio and ΔCPV%/ΔTBW% ratio was examined. Results The amount of intradialytic P removal from ICF positively correlated to the amount of ICW volume reduction (R = 0.279, y = 66.3x+285, p = 0.0076). It indicates an average of 66.3mg of P was removed from ICF per 1L of ICW reduction. In HR group, the amount of P removal from ICF was significantly larger than that in LR group (315.6±117.8mg vs 383.7±121.7mg, p = 0.019). ΔICW% negatively correlated to ECW/TBW ratio (R = 0.481, p = 0.000057). High ECW/TBW ratio indicates excess of ECW, which suggests having edema. ΔICW% positively correlated to ΔCPV% (R = 0.511, p = 0.0000051). Low ΔCPV% suggests insufficient of ultrafiltration. ΔICW% negatively correlated to ΔCPV%/ΔTBW% ratio (R = 0.421, p = 0.00011). High ΔCPV%/ΔTBW% ratio indicates insufficient plasma refilling for ultrafiltration rate, which suggests overrate of ultrafiltration. But ΔICW% did not correlate to ΔCPV%/ΔBW% ratio (R = 0.184, p = 0.10) nor ΔCPV%/ΔLBM% ratio (R = 0.176, p = 0.12). Conclusion The amount of intradialytic P removal from ICF correlated to the amount of ICW reduction. For efficient reduction of ICW, low ECW/TBW ratio, high ΔCPV% and low ΔCPV%/ΔTBW% ratio were required. It was suggested that efficient P removal was achieved when non-edematous patients get ultrafiltration of appropriate rate and dose.

Rapid and precise tracking of water influx and efflux across cell membranes induced by a pulsed electric field.

Quantitative measurements of water content within a single cell are notoriously difficult. In this work, we introduce a single-shot optical method for tracking the intracellular water content, by mass and volume, of a single cell at video rate. We utilize quantitative phase imaging and a priori knowledge of a spherical cellular geometry, leveraging a two-component mixture model to compute the intracellular water content. We apply this technique to study CHO-K1 cells responding to a pulsed electric field, which induces membrane permeabilization and rapid water influx or efflux depending upon the osmotic environment. The effects of mercury and gadolinium on water uptake in Jurkat cells following electropermeabilization are also examined.

Translocation and Utilization Mechanisms of Leaf Intracellular Water in Karst Plants Orychophragmus violaceus (L.) O. E. Schulz and Brassica napus L.

Orychophragmus violaceus (L.) O. E. Schulz adapts to karst environments through a variety of adaptability mechanisms. However, the leaf intracellular water translocation and utilization mechanism is still unknown. This study hypothesizes that plants adapt to dehydration by synergistically adjusting the leaf anatomy, cell elasticity and intracellular water translocation. Leaf structure, elastic modulus (Em), physiological capacitance (CP), impedance (Z), water potential (ΨL), leaf tensity (LT) and chlorophyll fluorescence parameters of the detached leaves in plants of O. violaceus and Brassica napus L. were measured at each water loss time (0, 1, 2, 3, 4 and 5 h). The uniform leaves were randomly selected from five different plants for each species. The cell vacuole volume and translocation resistance of intracellular water could be represented by the electrophysiological parameters, such as CP and Z. The results indicated that timely shrinkage of O. violaceus leaves and mesophyll cells together with the increased water translocation resistance retained the intracellular water and maintained the turgor pressure. Water within sponge parenchyma could also be translocated into palisade parenchyma. The PSII reaction center was kept stable, and the photosynthetic activity of O. violaceus was clearly inhibited at 3 h. Palisade parenchyma of B. napus leaves increased quickly to improve the intercellular water translocation due to the strong cell stiffness. Gradually increasing intracellular water translocation resistance and recovery of the cell elasticity slowed down the leaf water loss, which, however, could not timely stop the damage on the PSII reaction center and the photochemical efficiency. The photochemical efficiency was seriously inhibited at 4 h and 5 h. The response mechanism of intracellular water to dehydration can be investigated with the help of leaf electrophysiological traits. However, the direct determination of plant drought resistance using electrophysiological information can still not be realized at present and needs further research.

Water Distribution Changes in Complex Decongestive Treatment for Leg Lymphedema: Quantitative Evaluation by Direct Segmental Multi-Frequency Bioimpedance Analysis.

Background: There is a need for a simple method for the quantitative evaluation of lymphedema swelling. In this study, we performed a direct segmental multi-frequency impedance analysis in patients with leg lymphedema.Methods: The subjects were 36 patients (6 men and 30 women) with 46 lymphedema legs. The average age was 61 years. All patients had International Society of Lymphology stage II lymphedema. Swelling ratio and ultrasound subcutaneous tissue echo-free space (FS) were examined. InBody 770 was used to measure the extracellular water (ECW), intracellular water (ICW), and total body water (TBW) volumes. Changes before and after complex decongestive treatment (CDT) were examined.Results: In 26 unilateral cases, the ECW, ICW, and TBW volumes of the affected legs were higher than those of the contralateral unaffected legs, and the ECW/TBW ratio was significantly higher in the affected legs (0.41) than in the contralateral unaffected legs (0.391). There was a significant correlation between the leg swelling ratio and the ECW/TBW ratio between the affected and contralateral unaffected legs (correlation coefficient=0.882). Ultrasound findings of the 46 affected legs were classified into no FS (group 0), minimal or only horizontal FS (group 1), and cobblestone-like FS (group 2). The ECW/TBW ratio of the affected legs in each group was 0.393 (14 legs), 0.407 (10 legs), and 0.426 (22 legs) respectively, demonstrating significant differences among the 3 groups. After CDT, the amount of water decreased in the affected legs and increased in the trunks and both upper limbs. The ECW/TBW ratio decreased significantly, from 0.432 to 0.414 in the affected legs, from 0.401 to 0.392 in the unaffected legs, and from 0.413 to 0.402 in the trunks. The ECW/TBW ratio had not changed and remained below 0.4 in the upper limbs.Conclusion: The segmental water contents measured by direct segmental multi-frequency impedance analysis correlates well with the degree of lymphedema swelling, and subcutaneous echo findings and can demonstrate water distribution change before and after CDT, which is considered to be a useful quantitative evaluation method for lymphedema. (This is secondary publication from Jpn J Phlebol 2020; 31(1): 1–7.)

Abstract 9: Pervasive White Matter Microstructure Dysintegrity Related To High Blood Pressure Among Asymptomatic Population

Background: Blood pressure is the strongest contributor to clinically evident cerebrovascular disease. We investigated the role of blood pressure on white matter (WM) microstructure among asymptomatic individuals without clinically evident cerebrovascular disease. Methods: We conducted a nested study within the UK Biobank, restricting our analysis to participants without cerebrovascular disease or dementia and with available brain diffusion tensor imaging (DTI). We tested for association between systolic blood pressure (SBP) and six different DTI metrics: fractional anisotropy (FA), mean diffusivity (MD), tensor mode (MO), intra-cellular volume fraction (ICVF), isotropic or free water volume fraction (ISOVF), and orientation dispersion index (OD) across 48 WM tracts using multivariable linear regression adjusted for potential confounders. We used Bonferroni-corrected p-values (0.05/48) for statistical significance. Results: We analyzed 33,440 participants. Mean age was 63.0 (SD 7.7), and 17,688 (53%) were female. Higher SBP is independently associated with pervasive decrease in FA and ICVF and increase in MD (Figure), after adjustment for vascular risk-factors. SBP was also associated with lower neurite OD (a more specific metric of axonal damage) in bilateral posterior corona radiata, external capsule, medial lemniscus, and corticospinal tracs. FA and OD of external capsule and posterior corona radiata had the largest drop per 10 mmHg increase of SBP (steepest slope). Conclusions: Higher SBP is associated with pervasive WM microstructure dysintegrity in asymptomatic individuals without evident cerebrovascular disease. DTI metrics of the posterior corona radiata and external capsule are most reflective of variations in SBP and may provide a potential biomarker to assess subtle WM microstructural damage in hypertensive patients or monitor treatment response in clinical trials.

Cortical microstructural associations with CSF amyloid and tau

AbstractBackgroundMulti‐shell diffusion MRI (dMRI) biophysical models can estimate intracellular (ICVF), extracellular (ECVF) and free water (ISOVF) volume fractions (VFs) in brain tissue, and may offer insight into Alzheimer's disease pathological processes. These microstructural measures can be calculated in the cortex using a gray matter specific model that may be sensitive to amyloid and tau burden. Here, we evaluated relationships between regional cortical microstructural VFs and CSF amyloid and tau biomarkers.MethodMulti‐shell dMRI and CSF biomarker data were available for 50 ADNI‐3 participants (age: 72.4±6.4 yrs; 20 male; 36 cognitively normal, 12 MCI, 2 dementia). Cortical ICVF, ECVF and ISOVF were estimated with the multi‐tissue spherical mean technique (MT‐SMT). Mean cortical measures were extracted from 4 lobes and the cingulate cortex, parcellated with FreeSurfer. Random‐effects linear regressions tested associations between regional dMRI measures and CSF pTau or Aβ42/Aβ40 burden, adjusting for age, sex, education, and grouping by scanning site. FDR (q=0.05) was used to correct for multiple comparisons across 5 regions, 3 diffusion measures, and 2 tests.ResultHigher Aβ42/Aβ40 was associated with lower ISOVF throughout the cortex (Figure 1), and higher ECVF and ICVF in the cingulate, frontal and temporal lobes. Higher ICVF was also found in the parietal cortex. Higher pTau was associated with higher ISOVF in the occipital and parietal lobes, and lower ECVF in the frontal and parietal lobes (Figure 2). No pTau ICVF associations were detected.ConclusionLower ICVF and higher ISOVF with greater amyloid and tau may indicate neuronal loss or edema, while lower ECVF could reflect, for example, as neuronal swelling or an influx of activated microglia. Lower ECVF with greater amyloid and tau burden may also reflect accumulation of large hydrophobic amyloid plaques and neurofibrillary tangles in the extracellular space. These results are preliminary and, as many factors influence dMRI measures, should be interpreted with caution. Future work will incorporate multimodal imaging to map associations of diffusion measures with localized PET‐derived amyloid and tau measures.

Neurite orientation dispersion and density imaging in evaluation of high-grade glioma-induced corticospinal tract injury

PurposeTo evaluate the application of neurite orientation dispersion and density imaging (NODDI) to brain glioma-induced corticospinal tract (CST) injury. Material and methodsTwenty-four patients with high-grade glioma (HGG) in or adjacent to the CST pathway and 12 matched healthy subjects underwent structural and diffusion MRI. The CSTs were reconstructed on the both sides. The CST features including morphological features (track number, average track length and track volume) and the diffusion parameter values including fractional anisotraphy (FA), mean diffusivity (MD), intracellular volume fraction (ICVF), isotropic or free water volume fraction (ISOVF) and orientation dispersion index (ODI) along the CST were calculated. The CST features were compared between the affected and healthy side for HGG patients and between the left and right side for healthy subjects. The relative CST features were compared across the healthy subjects, patients with motor weakness and patients with normal muscle strength. Receiver operating characteristic (ROC) curve was applied to evaluate the performance of each relative CST characteristic for HGG-induced CST changes. ResultsCompared with the CST features on the healthy side, the track number, track volume and FA along the CST changed significantly on the affected side for HGG patients (p < 0.05 for all), whereas MD and ICVF changed significantly on the affected side only for HGG patients with motor weakness (p = 0.012 for both). In patients with motor weakness, the relative MD was significantly higher (p < 0.001), whereas the relative FA and ICVF was significantly lower (p = 0.002 and <0.001) than those in patients with normal muscle strength. The relative ICVF had a similar area under curve (AUC) to that of MD (AUC=0.953 and 0.969). Compared with the relative CST features in the healthy subjects, only the relative ICVF was significantly lower in HGG patients with normal muscle strength (p = 0.012). ConclusionsNODDI seems to be useful in reflecting the HGG infiltration to CST, and can evaluate the CST destruction with a performance similar to DTI by providing additional information about neurite density for HGG-induced CST injury.

Oropharyngeal Dysphagia in Older People is Associated with Reduced Pharyngeal Sensitivity and Low Substance P and CGRP Concentration in Saliva.

Substance P (SP) and Calcitonine gene-related peptide (CGRP) are released by sensory nerve fibers in the oropharynx. Patients with oropharyngeal dysphagia (OD) present reduced oropharyngeal sensitivity and low SP concentration in saliva. We aimed to assess the concentration of salivary SP and CGRP in healthy volunteers, and older people without and with OD, and the relationship with pharyngeal sensory threshold. We included 15 healthy volunteers, 14 healthy elderly and 14 elderly with OD. Swallow function was assessed by videofluoroscopy (VFS). Pharyngeal sensory threshold was assessed by intrapharyngeal electrical stimulation. Hydration and phase angle were assessed by bioimpedance. Saliva samples were collected with a Salivette® to determine SP and CGRP concentration by ELISA. Elderly patients with OD presented impaired safety of swallow (PAS 4.38 ± 0.77 p < 0.0001 vs. healthy volunteers = 1 and healthy elderly = 1.43 ± 0.51). Healthy elderly and elderly with OD presented a reduction in intracellular water and saliva volume (healthy elderly, 592.86 ± 327.79μl, p = 0.0004; elderly with OD, 422.00 ± 343.01μl, p = 0.0001 vs healthy volunteers, 1333.33 ± 615.91μl, r = 0.6621, p < 0.0001). Elderly patients with OD presented an impairment in pharyngeal sensory threshold (10.80 ± 3.92mA vs. healthy volunteers, 5.74 ± 2.57mA; p = 0.007) and a reduction in salivary SP (129.34pg/ml vs. healthy volunteers: 173.89pg/ml; p = 0.2346) and CGRP levels (24.17pg/ml vs. healthy volunteers: 508.18pg/ml; p = 0.0058). There was a negative correlation between both SP and CGRP concentrations and pharyngeal sensory threshold (r = - 0.450, p = 0.024; r = - 0.4597, p = 0.036, respectively), but only SP identified elderly patients with OD with higher pharyngeal sensory threshold. Elderly patients with OD presented hydropenia and sarcopenia, reduced salivary SP and CGRP and impaired pharyngeal sensitivity. Our study suggests SP levels in saliva as a potential biomarker to monitor pharyngeal sensitivity in elderly patients with OD.

Reproducibility of fluid status measured by bioelectrical impedance analysis in healthy volunteers: akey requirement to monitor fluid status in the intensive care unit.

Little is known about the use of bioelectrical impedance analysis (BIA) in critically ill patients. The objective of this study was to evaluate the reproducibility of BIA measurements by comparing non-dominant versus dominant body-side measurements at 2 separate time points in healthy volunteers in order to extrapolate key elements that may be of relevance in critically ill patients. Aprospective observational validation experiment was carried out in healthy volunteers. Full-body and segmental multiple frequency BIA measurements were carried out at the non-dominant and the dominant body side, consecutively, and on 2 separate occasions within 1 week. Parameters of interest were both raw data (impedance and phase angle) at the individual frequencies (5-50-100-200 kHz) and body fluid compartment volume estimations (total body water, extracellular water volume, intracellular water volume, volume excess). Atotal of 42 measurements were performed in 22 volunteers. Median (interquartile range) age and time between measurements was 26 years (24; 35) and 2.07 days (1.00; 2.99), respectively. The intraclass-correlation coefficients (ICCs) for body fluid compartment volumes estimated by full-body BIA, were greatly above 90%, showing excellent agreement, except for volume excess which showed moderate agreement. Full-body raw impedance and phase angle measurements showed highly variable and much lower ICCs. For both estimated body fluid compartment volumes and raw measurements, segmental BIA showed also highly variable and low ICCs. Overall this study showed that in healthy volunteers, BIA-derived fluid parameters are reproducible, and differences can be attributed to the changes in clinical status.

CrossTalk proposal: Apical NKCC1 of choroid plexus epithelial cells works in the net inward flux mode under basal conditions, maintaining intracellular Cl- and cell volume.

CrossTalk proposal: Apical NKCC1 of choroid plexus epithelial cells works in the net inward flux mode under basal conditions, maintaining intracellular Cl- and cell volume.

Differences in pharmacological property between combined therapy of the vasopressin V2-receptor antagonist tolvaptan plus furosemide and monotherapy of furosemide in patients with hospitalized heart failure

BackgroundTolvaptan has been shown to improve congestion in heart failure patients. The purpose of this study was to evaluate the pharmacology and clinical efficacy of combined tolvaptan and furosemide therapy. MethodsThis study included 40 patients with systemic volume overload who were hospitalized for heart failure. Patients who showed no improvement in the condition after receiving 20 mg intravenous furosemide were included and were randomly selected to receive tolvaptan as an add-on to furosemide or to receive an increased dose of furosemide. We evaluated the bioelectrical impedance analyzer parameters, the parameters of the inferior vena cava using echocardiography, vital signs, body weight, urine output, and laboratory data for 5 days. ResultsIn the changes from baseline between intracellular water volume (ICW) and extracellular water volume (ECW) after additional use of tolvaptan or furosemide from Day 1 to Day 5, there were no significant differences observed between ICW and ECW over 5 days in the tolvaptan + furosemide group, although differences were found in the furosemide group from Day 2 onward. Changes in the respiratory collapse of inferior vena cava increased significantly, and systolic blood pressure decreased significantly only in the furosemide group. ConclusionsThe present study clearly demonstrates that combined therapy with tolvaptan and furosemide removed excess ICW and ECW to an equal extent, while furosemide alone primarily removed ECW, including intravascular water.

Microstructure Modeling of High b-Value Diffusion-Weighted Images in Glioblastoma.

Apparent diffusion coefficient has limits to differentiate solid tumor from normal tissue or edema in glioblastoma (GBM). This study investigated a microstructure model (MSM) in GBM using a clinically available diffusion imaging technique. The MSM was modified to integrate with bi-polar diffusion gradient waveforms, and applied to 30 patients with newly diagnosed GBM. Diffusion-weighted (DW) images acquired on a 3 T scanner with b-values from 0 to 2500 s/mm2 were fitted in volumes of interest (VOIs) of solid tumor to obtain the apparent restriction size of intracellular water (ARS), the fractional volume of intracellular water (Vin), and extracellular (Dex) water diffusivity. The parameters in solid tumor were compared with those of other tissue types by Students’ t test. For comparison, DW images were fitted by conventional mono-exponential and bi-exponential models. ARS, Dex, and Vin from the MSM in tumor VOIs were significantly greater than those in WM, GM, and edema (P values of .01–.001). ARS values in solid tumors (from 21.6 to 34.5 um) had absolutely no overlap with those in all other tissue types (from 0.9 to 3.5 um). Vin values showed a descending order from solid tumor (from 0.32 to 0.52) to WM, GM, and edema (from 0.05 to 0.25), consisting with the descending cellularity in these tissue types. The parameters from mono-exponential and bi-exponential models could not significantly differentiate solid tumor from all other tissue types, particularly from edema. Further development and histopathological validation of the MSM will warrant its role in clinical management of GBM.

The intracellular water volume modulates the accumulation of cadmium in Euglena gracilis

In order to describe a relatively novel mechanism associated to heavy metal resistance in Euglena gracilis, the osmotic responses during cadmium accumulation were analyzed. Several physiological/biochemical parameters were assessed in E. gracilis exposed to 50 and 200 μM Cd2+, concentrations well within the range found in polluted soils and aquatic environments. The Cd2+ accumulation attained after only 24 h exposure induced marked increases in both the intracellular water volume and cellular size, which were maintained for several days; these changes correlated with (i) an increased intracellular osmolarity (i.e. osmotic pressure) driven by a generalized increase in the osmo-metabolites (trehalose, phosphate-molecules, amino acids, thiol-molecules, betaines and polyamines) content; and (ii) the triggering of antioxidant defenses (increased GSH/GSSG ratios and GPx, GR and APx activities). In contrast, no changes in intracellular volume, cellular size and antioxidant status were observed under hyperaccumulation of Zn2+. Furthermore, E. gracilis cultured in a hypoosmotic medium promoted greater Cd2+ accumulation and water volume, compared to a hyperosmotic medium. These changes were significantly decreased by the aquaporin inhibitors Hg2+ and pentamidine. The results suggested that the cell responses to Cd2+ and osmotic stress share biochemical mechanisms in this algae-like protist, in which Cd2+ accumulation closely correlates with the intracellular water volume changes in an oxidative stress-mediated process.

Myocardial native-T1 times are elevated as a function of hypertrophy, HbA1c, and heart rate in diabetic adults without diffuse fibrosis

PurposeCardiac native-T1 times have correlated to extracellular volume fraction in patients with confirmed fibrosis. However, whether other factors that can occur either alongside or independently of fibrosis including increased intracellular water volume, altered magnetization transfer (MT), or glycation of hemoglobin, lengthen T1 times in the absence of fibrosis remains unclear. The current study examined whether native-T1 times are elevated in hypertrophic diabetics with elevated hemoglobin A1C (HbA1c) without diffuse fibrosis. MethodsNative-T1 times were quantified in 27 diabetic and 10 healthy adults using a modified Look-Locker imaging (MOLLI) sequence at 1.5 T. The MT ratio (MTR) was quantified using dual flip angle cine balanced steady-state free precession. Gadolinium (0.2 mmol/kg Gd-DTPA) was administered as a bolus and post-contrast T1-times were quantified after 15 min. Means were compared using a two-tailed student's t-test, while correlations were assessed using Pearson's correlations. ResultsWhile left ventricular volumes, ejection fraction, and cardiac output were similar between groups, left ventricular mass and mass-to-volume ratio (MVR) were significantly higher in diabetic adults. Mean ECV (0.25 ± 0.02 Healthy vs. 0.25 ± 0.03 Diabetic, P = 0.47) and MTR (125 ± 16% Healthy vs. 125 ± 9% Diabetic, P = 0.97) were similar, however native-T1 times were significantly higher in diabetics (1016 ± 21 ms Healthy vs. 1056 ± 31 ms Diabetic, P = 0.00051). Global native-T1 times correlated with MVR (ρ = 0.43, P = 0.008) and plasma HbA1c levels (ρ = 0.43, P = 0.0088) but not ECV (ρ = 0.06, P = 0.73). Septal native-T1 times correlated with septal wall thickness (ρ = 0.50, P = 0.001). ConclusionIn diabetic adults with normal ECV values, elevated native-T1 times may reflect increased intracellular water volume and changes secondary to increased hemoglobin glycation.

Novel equations for bioimpedance spectroscopy to calculate body fluid volume based on the agreement between body weight and extracellular water change before and after hemodialysis as a guide

BackgroundMLT-550N is a device to measure the body fluid volume based on bioimpedance spectroscopy. When extracellular water (ECW) or total body water (TBW) is measured with MLT-550N before and after hemodialysis, the change in ECW (ΔECW) or TBW (ΔTBW) is markedly larger than the change in body weight (ΔW). Good agreements between ΔECW and ΔTBW calculated by Moissl equations with ΔW were reported. The aim of this study was to develop novel equations to calculate the body fluid volume by modifying Moissl equations.MethodsA total of 466 measurements of 351 hemodialysis patients were used to develop the novel equations. The equations were based on the agreement between ΔECW and ΔW as a guide. The volume of intracellular water was postulated to be constant during hemodialysis. For evaluation of the equations, 5485 measurements of 627 patients were used. Agreements between values of two groups were assessed with Lin’s concordance correlation coefficients. The normal edema ratio (ER = ECW/TBW) corrected with the fat ratio (fcER) according to the parameters of normally hydrated lean and adipose tissues was used as the reference for normal hydration. The fluid status at dry weight was considered to be close to normal. The absolute values of the deviated ratio of actual ER (aER) from fcER (dER = (aER−fcER)/fcER) were compared. In this study, 1 L of body water corresponded to 1.02 kg of body fluid according to a previous report.ResultsThe concordance correlations between ΔW and 1.02∙ΔECW or 1.02∙ΔTBW with the novel equations were higher than with the MLT method or Moissl equations (0.896, 0.596 vs. 0.411, 0.375 or 0.813, 0.411, respectively). The median value of dER with the novel equations was the lowest (0.062) compared with those of the MLT method and Moissl equations (0.164 and 0.144) (p < 0.001).ConclusionsThe agreements between ΔECW or ΔTBW and ΔW were improved by the novel equations compared with the MLT method or Moissl equations. Based on the relation between aER and fcER at dry weight, the fluid volume calculated using the novel equations may be more adequate than those with the MLT method or Moissl equations.

Dynamic Contrast-Enhanced MRI-Derived Intracellular Water Lifetime (τ i ): A Prognostic Marker for Patients with Head and Neck Squamous Cell Carcinomas.

Shutter-speed model analysis of dynamic contrast-enhanced MR imaging allows estimation of mean intracellular water molecule lifetime (a measure of cellular energy metabolism) and volume transfer constant (a measure of hemodynamics). The purpose of this study was to investigate the prognostic utility of pretreatment mean intracellular water molecule lifetime and volume transfer constant in predicting overall survival in patients with squamous cell carcinomas of the head and neck and to stratify p16-positive patients based upon survival outcome. A cohort of 60 patients underwent dynamic contrast-enhanced MR imaging before treatment. Median, mean intracellular water molecule lifetime and volume transfer constant values from metastatic nodes were computed from each patient. Kaplan-Meier analyses were performed to associate mean intracellular water molecule lifetime and volume transfer constant and their combination with overall survival for the first 2 years, 5 years, and beyond (median duration, >7 years). By the last date of observation, 18 patients had died, and median follow-up for surviving patients (n = 42) was 8.32 years. Patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .01) prolonged overall survival by 5 years compared with those with low mean intracellular water molecule lifetime (13 deaths). Similarly, patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .006) longer overall survival at long-term duration than those with low mean intracellular water molecule lifetime (14 deaths). However, volume transfer constant was a significant predictor for only the 5-year follow-up period. There was some evidence (P < .10) to suggest that mean intracellular water molecule lifetime and volume transfer constant were associated with overall survival for the first 2 years. Patients with high mean intracellular water molecule lifetime and high volume transfer constant were associated with significantly (P < .01) longer overall survival compared with other groups for all follow-up periods. In addition, p16-positive patients with high mean intracellular water molecule lifetime and high volume transfer constant demonstrated a trend toward the longest overall survival. A combined analysis of mean intracellular water molecule lifetime and volume transfer constant provided the best model to predict overall survival in patients with squamous cell carcinomas of the head and neck.