Fluids and body composition during anesthesia in children and adolescents: A pilot study.

The purpose of this study is to evaluate the intracellular and extracellular volume before and after anesthesia in order to ascertain their variations and determine the potential utility of this information in optimizing intraoperative fluid administration practices. A bioimpedance spectroscopy device (body composition monitor, BCM) was used to measure total body fluid volume, extracellular volume, and intracellular volume. BCM measurements were performed before and after general anesthesia in unselected healthy children and adolescents visiting the Pediatric Institute of Southern Switzerland for low-risk surgical procedures hydrated with an isotonic solution. In 100 children and adolescents aged 7.0 (4.8-11) years (median and interquartile range), the average total body water increased perioperatively with a delta value of 182 (0-383) mL/m2 from pre- to postoperatively, as well as the extracellular water content, which had a similar increase with a delta value of 169 (19-307) mL/m2. The changes in total body water and extracellular water content significantly correlated with the amount of fluids administered. The intracellular water content did not significantly change.   Conclusion: Intraoperative administration of isotonic solutions results in a significant fluid accumulation in low-risk schoolchildren during general anesthesia. The results suggest that children without major health problems undergoing short procedures do not need any perioperative intravenous fluid therapy, because they are allowed to take clear fluids up to 1 h prior anesthesia. In future studies, the use of BCM measurements has the potential to be valuable in guiding intraoperative fluid therapy. What is Known: • Most children who undergo common surgical interventions or investigations requiring anesthesia are nowadays hydrated at a rate of 1700 mL/m2/day with an isotonic solution. • The use bioimpedance spectroscopy for the assessment of fluid status in healthy children has already been successfully validated. • The bioimpedance spectroscopy is already currently widely used in various nephrological settings to calculate fluid overload and determine patient's optimal fluid status. What is New: • Routine intraoperative fluid administration results in a significant fluid accumulation during general anesthesia in low-risk surgical procedures. • This observation might be relevant for children and adolescents with conditions predisposing to fluid retention. • In future studies, the use of BCM measurements has the potential to be valuable in guiding intraoperative fluid therapy.

Association between ICW/TBW ratio and cancer prognosis: Subanalysis of a population-based retrospective multicenter study.

BACKGROUND & AIMS: Disease burden is known to alter cellular integrity and water balance. Therefore, the intracellular water/total body water (ICW/TBW) ratio is used as an adjunctive indicator to predict disease severity and prognosis. The ICW/TBW ratio of patients with cancer, who typically present with low muscle mass, poor nutritional status, and high inflammatory response, reportedly differs from that of the healthy population. Herein, we aimed to evaluate the effect of the ICW/TBW ratio on the prognosis of different subgroups of patients with cancer. METHODS: This multicenter cohort study included 2787 patients with malignancies between June 2014 and December 2018. The association between covariates and overall survival (OS) was assessed using restricted cubic spline models. The multivariate Cox regression model included variables demonstrating a statistical significance in the univariate Cox regression analysis (P < 0.05) without multicollinearity. The generated nomogram used the C-index and calibration curves to validate the predictive accuracy of the scoring system. RESULTS: The optimal cut-off value for the ICW/TBW ratio was 0.61. The ICW/TBW ratio was an independent prognostic factor (hazard ratio [HR]: 0.621; 95 % confidence interval [CI]: 0.537-0.719, P < 0.001). Moreover, the ICW/TBW ratio had a greater impact on the prognosis of patients receiving chemoradiotherapy than on those receiving chemotherapy alone (chemoradiotherapy: HR = 0.495, P = 0.005 vs. chemotherapy: HR = 0.646, P < 0.001). Multivariate Cox regression analysis showed that sex, age, tumor stage, body mass index, neutrophil-to-lymphocyte ratio (NLR), and ICW/TBW ratio were associated with OS. Subsequently, a nomogram was developed incorporating these variables and yielded a C-index of 0.743. CONCLUSIONS: The ICW/TBW ratio was associated with muscle mass, nutritional status, and inflammation. A low ICW/TBW ratio is an independent risk factor for poor prognosis in patients with cancer, especially when they are female, have advanced cancer stage, have sarcopenia, and are receiving radiotherapy.

Prognostic value of the combined effect of nutritional status and body water component in patients with colorectal cancer.

The aim of this study was to explore the impact of Geriatric Nutritional Risk Index (GNRI) and body water component (BWC) on the survival of colorectal cancer (CRC) patients and whether the combined effect had a potential prognostic and predictive efficacy. We evaluated the accuracy of GNRI for malnutrition and estimated the predictive capacity of BWC for survival. Kaplan-Meier survival curves and cox regression analyses were used to examine the prognostic effects. A nutrition-water score (NWS) model was developed and evaluated the survival predictive power. GNRI and extracellular water-to-intracellular water ratio (ECW/ICW) were integrated, with the cut-off values of 103.5 and 63.7%. Lower GNRI and higher ECW/ICW were independent risk factors for poor prognosis in CRC patients. The combination of the two into the NWS model demonstrated a higher risk of death for patients with NWS ≥ 1 compared to those with NWS of 0. NWS showed a better predictive capability compared to GNRI and ECW/ICW, with the concordance index of 0.681. Our study demonstrates GNRI and ECW/ICW's prognostic utility in CRC, with their combination improving survival prediction to help guide patient-centered treatment.

Association of extracellular water/total body water ratio with protein-energy wasting and mortality in patients on hemodialysis.

Bioimpedance analysis-assessed extracellular water/total body water (ECW/TBW) ratio may be a marker for mortality and poor nutritional status in hemodialysis patients. In 193 maintenance hemodialysis patients, we retrospectively investigated the relationships among ECW/TBW ratio, mortality, and protein-energy wasting (PEW). Four components-body mass index, normalized protein catabolic rate, normalized serum creatinine level, and serum albumin level-constitute the simple PEW score; this score was calculated based on the positive number of items concerning malnutrition among these four components. A score ≥ 3 indicated PEW. Patients were stratified by an ECW/TBW ratio cut-off value (0.40) and by PEW versus non-PEW status. The simple PEW score, cardiothoracic ratio, and log-transformed C-reactive protein level were independently correlated with the ECW/TBW ratio. Eighty-four patients died during follow-up (median 4.3 years). After adjustments for sex, age, hemodialysis vintage, histories of cardiovascular events and diabetes, and C-reactive protein level, a higher ECW/TBW ratio and PEW were independently related to elevated risks of all-cause death. Adding the ECW/TBW ratio to a baseline risk model including PEW significantly increased C-statistics from 0.788 to 0.835. In conclusion, the ECW/TBW ratio may be an indicator of PEW and may be a predictor of death even accounting for PEW, in hemodialysis patients.

Aquaporin water channels: roles beyond renal water handling.

Aquaporin (AQP) water channels are pivotal to renal water handling and therefore in the regulation of body water homeostasis. However, beyond the kidney, AQPs facilitate water reabsorption and secretion in other cells and tissues, including sweat and salivary glands and the gastrointestinal tract. A growing body of evidence has also revealed that AQPs not only facilitate the transport of water but also the transport of several small molecules and gases such as glycerol, H2O2, ions and CO2. Moreover, AQPs are increasingly understood to contribute to various cellular processes, including cellular migration, adhesion and polarity, and to act upstream of several intracellular and intercellular signalling pathways to regulate processes such as cell proliferation, apoptosis and cell invasiveness. Of note, several AQPs are highly expressed in multiple cancers, where their expression can correlate with the spread of cancerous cells to lymph nodes and alter the response of cancers to conventional chemotherapeutics. These data suggest that AQPs have diverse roles in various homeostatic and physiological systems and may be exploited for prognostics and therapeutic interventions.

Cellular Exchange Imaging (CEXI): Evaluation of a diffusion model including water exchange in cells using numerical phantoms of permeable spheres.

PURPOSE: Biophysical models of diffusion MRI have been developed to characterize microstructure in various tissues, but existing models are not suitable for tissue composed of permeable spherical cells. In this study we introduce Cellular Exchange Imaging (CEXI), a model tailored for permeable spherical cells, and compares its performance to a related Ball & Sphere (BS) model that neglects permeability. METHODS: We generated DW-MRI signals using Monte-Carlo simulations with a PGSE sequence in numerical substrates made of spherical cells and their extracellular space for a range of membrane permeability. From these signals, the properties of the substrates were inferred using both BS and CEXI models. RESULTS: CEXI outperformed the impermeable model by providing more stable estimates cell size and intracellular volume fraction that were diffusion time-independent. Notably, CEXI accurately estimated the exchange time for low to moderate permeability levels previously reported in other studies ( κ < 25 µ m / s $$ \kappa <25\kern0.3em \mu \mathrm{m}/\mathrm{s} $$ ). However, in highly permeable substrates ( κ = 50 µ m / s $$ \kappa =50\kern0.3em \mu \mathrm{m}/\mathrm{s} $$ ), the estimated parameters were less stable, particularly the diffusion coefficients. CONCLUSION: This study highlights the importance of modeling the exchange time to accurately quantify microstructure properties in permeable cellular substrates. Future studies should evaluate CEXI in clinical applications such as lymph nodes, investigate exchange time as a potential biomarker of tumor severity, and develop more appropriate tissue models that account for anisotropic diffusion and highly permeable membranes.

The association between hydration status and body composition in healthy children and adolescents.

OBJECTIVES: Children 10-20 years old in the US are currently obese, showing suboptimal hydration as 60% fail to meet the US Dietary Reference Intakes for water. Studies have shown a significant inverse association between hydration status and body composition in children, although most failed to use the Dual-X-Ray Absorptiometry Scan (DEXA), the gold standard for body composition. Limited studies used an objective marker to measure hydration, such as urine specific gravity (USG) from a 24-h urine collection. Therefore, this study aimed to examine the association between hydration status (measured from USG in a 24-h urine sample and assessed from three 24-h dietary recalls) and body fat % and lean mass (assessed from a DEXA scan) in children (10-13 years, n=34) and adolescents (18-20 years, n=34). METHODS: Body composition was measured using DEXA, total water intake (mL/d) was assessed from three 24-h dietary recalls and analyzed using the Nutrition Data System for Research (NDSR). Hydration status was objectively measured using USG via 24-h urine collection. RESULTS: Overall body fat % was 31.7 ± 7.31, total water intake was 1746 ± 762.0 mL/d, and USG score was 1.020 ± 0.011 uG. Linear regressions showed significance between total water intake and lean mass (B=12.2, p<0.05). Logistic regressions showed no significant association between body composition and USG and total water intake. CONCLUSIONS: Findings showed total water intake was significantly associated with lean mass. Future research should be conducted to explore other objective markers of hydration and with a larger sample.

Ratio of extracellular water to intracellular water and simplified creatinine index as predictors of all-cause mortality for patients receiving hemodialysis.

The bioelectrical impedance analysis-measured ratio of extracellular water (ECW) to intracellular water (ICW) reflects fluid volume and malnutrition. It may be an indicator of protein-energy wasting and muscle wasting in hemodialysis patients. We examined the association between the ECW/ICW ratio and simplified creatinine index, which is a new surrogate marker of protein-energy wasting and muscle wasting, and whether their combination can accurately predict mortality. A total of 224 patients undergoing hemodialysis for more than 6 months and having undergone bioelectrical impedance analysis for the assessment of body composition were included. Patients were divided into two groups based on the cut-off values of the ECW/ICW ratio (0.57) and simplified creatinine index (20.4 mg/kg/day) for maximumly predicting mortality. Thereafter, they were cross-classified into four groups with each cut-off point. The ECW/ICW ratio was independently associated with the simplified creatinine index (ß = -0.164; P = 0.042). During a follow-up of 3.5 years (2.0-6.0 years), 77 patients died. A higher ECW/ICW ratio (adjusted hazard ratio, 3.66, 95% confidence interval 1.99-6.72, P <0.0001) and lower simplified creatinine index (adjusted hazard ratio, 2.25, 95% confidence interval 1.34-3.79, P = 0.0021) were independently associated with an increased risk of all-cause mortality. The adjusted hazard ratio for the higher ECW/ICW ratio and lower simplified creatinine index group vs. the lower ECW/ICW ratio and higher simplified creatinine index group was 12.22 (95% confidence interval 3.68-40.57, p <0.0001). Furthermore, the addition of the ECW/ICW ratio and simplified creatinine index to the baseline risk model significantly improved the C-index from 0.831 to 0.864 (p = 0.045). In conclusion, the ECW/ICW ratio may be a surrogate marker of muscle wasting. Moreover, combining the ECW/ICW ratio and simplified creatinine index may improve the accuracy of predicting all-cause mortality and help stratify the mortality risk of hemodialysis patients.

Simultaneous estimation of the cellular water exchange rate, intracellular volume fraction, and longitudinal relaxation rate in cancer cells.

The purpose of the current study was to investigate the feasibility of simultaneously estimating the cellular water efflux rate ( k ie ), intracellular longitudinal relaxation rate ( R 10 i ), and intracellular volume fraction ( v i ) of a cell suspension using multiple samples with different gadolinium concentrations. Numerical simulation studies were conducted to assess the uncertainty in the estimation of k ie , R 10 i , and v i from saturation recovery data using single (SC) or multiple concentrations (MC) of gadolinium-based contrast agent (GBCA). In vitro experiments with 4 T1 murine breast cancer and SCCVII squamous cell cancer models were conducted at 11 T to compare parameter estimation using the SC protocol with that using the MC protocol. The cell lines were challenged with a Na+ /K+ -ATPase inhibitor, digoxin, to assess the treatment response in terms of k ie , R 10 i , and v i . Data analysis was conducted using the two-compartment exchange model for parameter estimation. The simulation study data demonstrate that the MC method, compared with the SC method, reduces the uncertainty of the estimated k ie by decreasing the interquartile ranges from 27.3% ± 3.7% to 18.8% ± 5.1% and the median differences from ground truth from 15.0% ± 6.3% to 7.2% ± 4.2%, while estimating R 10 i and v i simultaneously. In the cell studies, the MC method demonstrated reduced uncertainty in overall parameter estimation compared with the SC approach. MC method-measured parameter changes in cells treated with digoxin increased R 10 i by 11.7% (p = 0.218) and k ie by 5.9% (p = 0.234) for 4 T1 cells, respectively, and decreased R 10 i by 28.8% (p = 0.226) and k ie by 1.6% (p = 0.751) for SCCVII cells, respectively. v i did not change noticeably by the treatment. The results of this study substantiate the feasibility of using saturation recovery data of multiple samples with different GBCA concentrations for simultaneous measurement of the cellular water efflux rate, intracellular volume fraction, and intracellular longitudinal relaxation rate in cancer cells.

Correlación del agua corporal total con la edad en pacientes con y sin diabetes mellitus tipo-2 en la población peruana / Correlation of total body water with age in patients with and without type-2 diabetes in the Peruvian population

Introducción. La disminución del agua corporal es un proceso fisiológicamente natural vinculado al avance de la edad; la diabetes podría incrementar esta relación. Objetivo. Analizar el grado de correlación entre el porcentaje de agua corporal total con la edad en adultos con y sin diabetes mellitus tipo 2 de la población peruana. Material y Métodos. Estudio observacional, analítico, retrospectivo y transversal. Los datos provinieron de la encuesta nacional demográfica del año 2022. La población fue de 29 737 adultos, de los cuales 16 956 son mujeres y 12 781. La muestra fue el total de la población encuestada. Las variables fueron: diabetes mellitus tipo-2, agua corporal total (ACT), porcentaje de agua corporal, sexo, edad. Las pruebas empleadas fueron el chi-cuadrado de Pearson, V de Cramer y correlación de Spearman. Resultados. El porcentaje de adultos con bajos niveles porcentuales de agua corporal total fue más frecuente en diabéticos que en no diabéticos. En la prueba de asociación V de Cramer, se encontró asociaciones estadísticamente significativas, las cuales fueron de un efecto mayor en hombres que en mujeres con y sin diabetes. En hombres diabéticos, la edad y el ACT se correlacionan de forma moderada y negativa (Rho=-0,601), en no diabéticos, se correlacionó baja y negativamente (Rho=-0,237). En mujeres diabéticas, la correlación es baja y negativa (Rho=-0,308), mientras que, en no diabéticas, es muy baja (Rho=-0,056). Conclusión. Existe una mayor correlación negativa entre la edad y el agua corporal total en diabéticos que en no diabéticos de ambos sexos. Palabras Clave: agua corporal; diabetes mellitus tipo 2; correlación de datos; envejecimiento; Perú

Introduction. The decrease in body water is a physiologically natural process linked to the advancement of age; diabetes could increase this relationship. Objective.To analyze the degree of correlation between the percentage of total body water with age in adults with and without type 2 diabetes mellitus in the Peruvian population. Material and Methods. Observational, analytical, retrospective and cross-sectional study. The data came from the national demographic survey of the year 2022. The population was 29,737 adults, of which 16,956 are women and 12,781. The sample was the total population surveyed. The variables were: type-2 diabetes mellitus, total body water (ACT), percentage of body water, sex, age. The tests used were Pearson's chi-square, Cramer's V and Spearman's correlation. Results:The percentage of adults with low percentage levels of totalbody water was more frequent in diabetics than in non-diabetics. In Cramer's V association test, statistically significant associations were found, which were of a greater effect in men than in women with and without diabetes. In diabetic men, age and ACTcorrelated moderately and negatively (Rho=-0.601), in non-diabetics, it correlated low and negatively (Rho=-0.237). In diabetic women, the correlation is low and negative (Rho=-0.308), while in non-diabetics it is very low (Rho=-0.056). Conclusions. Thereis a greater negative correlation between age and total body water in diabetics than in non-diabetics of both sexes. Key words:body water; diabetes mellitus,type 2; correlation of data; aging; Peru

Bioimpedance spectroscopy fluid analysis in acute high-risk abdominal surgery, a prospective clinician-blinded observational feasibility study.

Objective assessment of fluid status in critical surgical care may help optimize perioperative fluid administration and prevent postoperative fluid retention. We evaluated the feasibility of hydration status and fluid distribution assessment by Bioimpedance spectroscopy Analysis (BIA) in patients undergoing acute high-risk abdominal (AHA) surgery. This observational study included 73 patients undergoing AHA surgery. During the observational period (0-120 h), we registered BIA calculated absolute fluid overload (AFO) and relative fluid overload (RFO), defined as AFO/extracellular water ratio, as well as cumulative fluid balance and weight. Based on RFO values, hydration status was classified into three categories: dehydrated (RFO < - 10%), normohydrated (- 10% ≤ RFO ≤ + 15%), overhydrated RFO > 15%. We performed a total of 365 BIA measurements. Preoperative overhydration was found in 16% of patients, increasing to 66% by postoperative day five. The changes in BIA measured AFO correlated with the cumulative fluid balance (r2 = 0.44, p < .001), and change in weight (r2 = 0.55, p < .0001). Perioperative overhydration measured with BIA was associated with worse outcome compared to patients with normo- or dehydration. We have demonstrated the feasibility of obtaining perioperative bedside BIA measurements in patients undergoing AHA surgery. BIA measurements correlated with fluid balance, weight changes, and postoperative clinical complications. BIA-assessed fluid status might add helpful information to guide fluid management in patients undergoing AHA surgery.

Increased extracellular water/body mass is associated with functional impairment in hemodialysis patients.

BACKGROUND: Functional impairment, malnutrition and fluid overload are prevalent in patients undergoing maintenance hemodialysis (MHD). The extracellular water/body cell mass ratio (ECW/BCM) is a new indicator reflecting fluid overload and malnutrition. A previous study has suggested that it performs better than other indices in assessing fluid status. This study investigates the relationship between pre-dialysis whole-body ECW/BCM and physical function in MHD patients. METHODS: We conducted a multicenter, cross-sectional study in Guizhou Province in Southwest China. The Karnofsky Performance Status (KPS) was used to evaluate patients' functional status. Patients with KPS scores of ≤ 80 were considered to have a functional impairment. The body composition was measured using the body composition monitor (BCM), and the value of the ECW/BCM ratio was calculated. The subjects were classified into three groups according to ECW/BCM tertiles. Multiple logistic regression models and interactive analyses were conducted. RESULTS: The final analysis included 2818 subjects. Multivariate logistic regression analyses showed that compared with the lowest tertile (tertile 1), the adjusted odds ratio of functional impairment were 1.95 (95% CI: 1.21-3.13, p < 0.001) and 2.10 (95% CI: 1.31-3.37, p < 0.001) in the second and the third tertiles of ECW/BCM, respectively after adjusting for age, sex, current smoking status, history of stroke, heart failure, diabetes, and myocardial infarction. Subgroup analysis showed that the association existed stably across all subgroups stratified by age, gender, cognitive impairment (CI), history of stroke, heart failure, and diabetes (all p values for interaction >0.05). CONCLUSIONS: Elevated ECW/BCM is independently linked to an increased risk of functional impairment in patients with MHD.

Association of differential body water composition by sex, measured using BIA, with survival in a real­world lung cancer cohort.

OBJECTIVE: The aim of this study was to evaluate the association of differential body water composition with survival in patients with lung cancer. METHODS: This retrospective cohort study included 1314 patients diagnosed with lung cancer in 80 Chinese institutions from May 2013 to August 2020. We calculated hazard ratios (HRs) to evaluate the associations of all-cause mortality with extracellular water (ECW) and intracellular water (ICW). Cox proportional risk regression models were adjusted for sociodemographic characteristics, tumor characteristics, treatment, body mass index (BMI), and body composition measures. We also evaluated cross-classification of the dichotomy of ECW and ICW with outcomes. The association among ECW, ICW, and survival was evaluated via Cox regression and the restricted cubic-spline model using a two-sided P value. RESULTS: The study included 819 (62%) men and 495 (28%) women. The HR of lung cancer mortality significantly decreased as ECW increased (HR, 0.96; 95% confidence interval [CI], 0.93-1.00) and ICW (HR, 0.97; 95% CI, 0.95-1.00) with cutoff values of 10.5 and 16.3 L, respectively. When patients were cross-classified into categories of sex, age, BMI, visceral fat index, pathology, tumor stage, tumor burden, total bilirubin, and neutrophil count, ICW and ECW were protective factors. Only sex interacted significantly with ICW or ECW. High ICW and ECW had significant protective effects, and women had a greater risk for death than men in the case of either poor ICW or poor ECW. Sensitivity analysis showed the protective effect of the higher dichotomy of ICW (HR, 0.52; 95% CI, 0.35-0.78) and ECW (HR, 0.45; 95% CI, 0.31-0.66) on female lung cancer patients by removing patients who died within 12 mo of diagnosis. CONCLUSION: Greater ICW and ECW, especially ICW, were independent predictors for better survival in patients with lung cancer. Female patients were more vulnerable to dehydration than male patients.

Side Bioimpedance Analysis in Menopausal Post-Oncological Breast Cancer.

BACKGROUND: Post-oncological BC (breast cancer) has an increased cardiovascular risk due to the variation of some anthropometric parameters. This study investigates the differences between a quadrantectomy and a mastectomy on the body composition over time in presence of a breast prothesis. METHODS: A group of BC patients (n = 41 aged 56.6 ± 9.5 years; 15 mastectomy patients; and 26 quadrantectomy patients) were compared to controls (C) (n = 22 aged 46.5 ± 13.44 years). Through bioimpedance analysis (Akern-BIA 101), the body mass index (BMI), total body water (TBW), extracellular water (ECW), body cell mass (BCM), fat mass (FM), free fat mass (FFM), and angle phase (PA) were compared within each group and between different groups using the Student's Test T. RESULTS: The BC group showed lower values of FFM and TBW compared to C. The FFM was significantly (p = 0.04) lower in those with quadrantectomy. The right hemisome of the quadrantectomy has increased values of FFM, BCM (p = 0.04) and TBW compared to the counter-lateral hemisome, and FM values (p = 0.0008) lower than the counter-lateral. The hemisome with intervention has increased values of FM and ECW compared to the counter lateral, as well the FFM, BCM, TBW, and PA. CONCLUSIONS: The results support the hypothesis that non-conservative surgical treatment (mastectomy) is associated with a better BIA profile without any substantial impact of breast implants in the body composition analysis. The awareness of a severe diseases could play a role to ameliorate lifestyle; however, further studies will be necessary to support this theory.

Association between Disability and Edema Index Values in Rural Older Adult Osteosarcopenia Patients.

PURPOSE: This study analyzed the relationship between degree of disability and edema index [extracellular water/total body water (ECW/TBW) ratio] values in a rural population of older adult patients with osteopenia, sarcopenia, or osteosarcopenia (OS). MATERIALS AND METHODS: This study used data from the Namgaram-2 cohort. The degree of disability was measured using the World Health Organization Disability Assessment Schedule (WHODAS) 12, and ECW/TBW ratio was calculated using bioelectrical impedance analysis. Based on ECW/TBW ratio, the participants were stratified into normal (<0.391) and abnormal (≥0.391) groups, and the mean WHODAS 12 scores were compared between the two groups. Multiple regression analysis corrected for demographic factors, smoking history, hypertension, diabetes, and serological test results was also conducted. RESULTS: Significant differences in mean WHODAS 12 scores were observed in the healthy group (5.8±7.4 vs. 9.2±9.7, p=0.008), the osteopenia only group (7.4±8.7 vs. 12.9±12.0, p<0.001), and the OS group (16.0±13.2 vs. 23.1±17.1, p=0.004). However, no significant difference in mean WHODAS 12 score was observed in the sarcopenia only group (14.9±13.4 vs. 20.7±14.8, p= 0.051). There were significant differences in ECW/TBW ratio values between the abnormal and normal groups in the osteopenia only group (B=4.646 and p=0.001), the sarcopenia only group (B=5.097 and p=0.016), and the OS group (B=5.653 and p=0.043). CONCLUSION: This study found that the degree of disability is related to the edema index in older patients with osteopenia, sarcopenia, or OS. Since the edema index indicates the nutritional status of an individual, proper nutrition and fluid intake are important to reduce disability.

Bio-impedance spectroscopy for total body water assessment in pediatric surgical patients: A single center pilot cohort study.

BACKGROUND: Excess peri­operative fluid administration is associated with higher morbidity and mortality. We aimed to examine the feasibility of bio-impedance spectroscopy (BIS) to record serial peri­operative fluid volumes in the pediatric surgical population. METHODS: Children who underwent major elective general surgery from March 2019 to March 2020 were included. Total body water (TBW) assessment by BIS was recorded prior to surgery and on subsequent post-operative days (POD). We recorded the duration, tolerance and completion of each BIS assessment. We used Spearman coefficient and Bland Altman analysis to examine correlation and agreement between fluid balance (FB) in ml/kg calculated from intake/output (IO) recording and measured by BIS. RESULTS: 20 (87%) of 23 consented patients, median age 2.5 (1-17) years and 13 (65%) male, completed pre-operative and post-operative measurements, and were included in the analysis. Median time required for BIS assessments was 10 (5-15) minutes, and there were no recorded side effects or intolerance. The correlation coefficient for fluid balance measurements on POD 1 between BIS and IO methods was 0.59 (p = 0.01); mean bias (limits) of agreement was 26 (111 to 163) mL/kg. The trend in TBW measured by BIS declined from POD 1-3, while the recorded FB increased. CONCLUSION: Bedside BIS is feasible and well-tolerated. Despite moderate correlation between fluid balance assessment by BIS and IO on POD 1, the wide limits of agreement between values from these methods preclude their use interchangeably. The role of BIS in assessment of fluid status in the pediatric surgical population should be further examined. LEVEL OF EVIDENCE: Level III.

Improving MR cell size imaging by inclusion of transcytolemmal water exchange.

The goal of the current study is to include transcytolemmal water exchange in MR cell size imaging using the IMPULSED model for more accurate characterization of tissue cellular properties (e.g., apparent volume fraction of intracellular space v in ) and quantification of indicators of transcytolemmal water exchange. We propose a heuristic model that incorporates transcytolemmal water exchange into a multicompartment diffusion-based method (IMPULSED) that was developed previously to extract microstructural parameters (e.g., mean cell size d and apparent volume fraction of intracellular space v in ) assuming no water exchange. For t diff ≤ 5 ms, the water exchange can be ignored, and the signal model is the same as the IMPULSED model. For t diff ≥ 30 ms, we incorporated the modified Kärger model that includes both restricted diffusion and exchange between compartments. Using simulations and previously published in vitro cell data, we evaluated the accuracy and precision of model-derived parameters and determined how they are dependent on SNR and imaging parameters. The joint model provides more accurate d values for cell sizes ranging from 10 to 12 microns when water exchange is fast (e.g., intracellular water pre-exchange lifetime τ in ≤ 100 ms) than IMPULSED, and reduces the bias of IMPULSED-derived estimates of v in , especially when water exchange is relatively slow (e.g., τ in > 200 ms). Indicators of transcytolemmal water exchange derived from the proposed joint model are linearly correlated with ground truth τ in values and can detect changes in cell membrane permeability induced by saponin treatment in murine erythroleukemia cancer cells. Our results suggest this joint model not only improves the accuracy of IMPULSED-derived microstructural parameters, but also provides indicators of water exchange that are usually ignored in diffusion models of tissues.

LRBA is essential for urinary concentration and body water homeostasis.

Protein kinase A (PKA) directly phosphorylates aquaporin-2 (AQP2) water channels in renal collecting ducts to reabsorb water from urine for the maintenance of systemic water homeostasis. More than 50 functionally distinct PKA-anchoring proteins (AKAPs) respectively create compartmentalized PKA signaling to determine the substrate specificity of PKA. Identification of an AKAP responsible for AQP2 phosphorylation is an essential step toward elucidating the molecular mechanisms of urinary concentration. PKA activation by several compounds is a novel screening strategy to uncover PKA substrates whose phosphorylation levels were nearly perfectly correlated with that of AQP2. The leading candidate in this assay proved to be an AKAP termed lipopolysaccharide-responsive and beige-like anchor protein (LRBA). We found that LRBA colocalized with AQP2 in vivo, and Lrba knockout mice displayed a polyuric phenotype with severely impaired AQP2 phosphorylation. Most of the PKA substrates other than AQP2 were adequately phosphorylated by PKA in the absence of LRBA, demonstrating that LRBA-anchored PKA preferentially phosphorylated AQP2 in renal collecting ducts. Furthermore, the LRBA-PKA interaction, rather than other AKAP-PKA interactions, was robustly dissociated by PKA activation. AKAP-PKA interaction inhibitors have attracted attention for their ability to directly phosphorylate AQP2. Therefore, the LRBA-PKA interaction is a promising drug target for the development of anti-aquaretics.

The clinical application value of the extracellular-water-to-total-body-water ratio obtained by bioelectrical impedance analysis in people with advanced cancer.

OBJECTIVES: Body-composition analysis using bioelectrical impedance analysis is gradually becoming more widely used in clinical practice. The ratio of extracellular water (ECW) to total body water (TBW) is thought to be related to the prognosis of a variety of diseases. However, its performance in people with advanced cancer deserves further discussion. METHODS: A retrospective analysis was performed on 784 people with advanced cancer. Anthropometric indicators, serologic indicators, nutritional status, health-related quality of life, and body composition were analyzed. Participants were grouped into two groups according to ECW/TBW ratio. We used t tests and χ2 tests to analyze differences between the groups. Univariate and multivariate Cox regressions were conducted to analyze the factors influencing overall survival. Logistic regression was used to analyze the related factors of malnutrition, and linear regression for factors of health-related quality of life. RESULTS: Age, body mass index, Patient-Generated Subjective Global Assessment score, Karnofsky Performance Status questionnaire score, skeletal muscle mass index, and fat-free mass index were statistically different between the non-overhydrated and overhydrated groups. Univariate and multivariate Cox regression models showed that an ECW/TBW ≥ 0.40 is a risk factor for poor prognosis in people with advanced cancer (hazard ratio = 1.511; 95% confidence interval, 1.103-2.070; P = 0.010). Subgroup analyses were next conducted according to tumor type, with ECW/TBW ≥ 0.40 emerging as a risk factor for poor prognosis for people with advanced breast cancer and advanced gastric cancer. Logistic regression showed that ECW/TBW ≥ 0.40 is a risk factor for malnutrition in people with advanced cancer (odds ratio = 1.988; 95% confidence interval, 1.049-3.767; P = 0.035). The univariate and multivariate linear regression models showed that the ECW/TBW ratio is an influencing factor for health-related quality of life in the domains of physical functioning, role functioning, and constipation. CONCLUSION: We found that in people with cancer, an ECW/TBW ≥ 0.40 was a risk factor for malnutrition and lower health-related quality of life, and in people with advanced cancer, it was a risk factor for poor prognosis.