No abstract available.
Extracellular Fluid ; Glucose ; Plasma

Brain extracellular space (ECS) is a narrow, irregular space, which provides immediate living environment for neural cells and accounts for approximately 15%-20% of the total volume of living brain. Twenty-five years ago, as an interventional radiologist, the author was engaged in investigating early diagnosis and treatment of cerebral ischemic stroke, and the parameters of brain ECS was firstly derived and demonstrated during the study of the permeability of blood-brain barrier (BBB) and its diffusion changes in the cerebral ischemic tissue. Since then, the author and his team had been working on developing a novel measuring method of ECS: tracer-based magnetic resonance imaging (MRI), which could measure brain ECS parameters in the whole brain scale and make the dynamic drainage process of the labelled brain interstitial fluid (ISF) visualized. By using the new method, the team made a series of new findings about the brain ECS and ISF, including the discovery of a new division system in the brain, named regionalized ISF drainage system. We found that the ISF drainage in the deep brain was regionalized and the structural and functional parameters in different interstitial system (ISS) divisions were disparate. The ISF in the caudate nucleus could be drained to ipsilateral cortex and finally into the subarachnoid space, which maintained the pathway of ISF-cerebrospinal fluid (CSF) exchange. However, the ISF in the thalamus was eliminated locally in its anatomical division. After verifying the nature of the barrier structure between different drainage divisions, the author proposed the hypothesis of "regionalized brain homeostasis". Thus, we demonstrated that the brain was protected not only by the BBB, which avoided potential exogenous damage through the vascular system, but was also protected by an internal ISF drainage barrier to avoid potentially harmful interference from other ECS divisions in the deep brain. With the new findings and the proposed hypothesis, an innovative therapeutic method for the treatment of encephalopathy with local drug delivery via the brain ECS pathway was established. By using this new administration method, the drug was achieved directly to the space around neurons or target regions, overwhelming the impendence from the blood-brain barrier, thus solved the obstacles of low efficiency in traditional drug investigation. At present, new methods and discoveries developed by the author and his team have been widely applied in several frontier fields including neuroscience, new drug research and development, neurodevelopment aerospace medicine, clinical encephalopathy treatment,new neural network modeling and so on.
Brain ; Caudate Nucleus ; Extracellular Fluid ; Extracellular Space ; Magnetic Resonance Imaging

No abstract available.
Cervix Uteri* ; Extracellular Fluid* ; Female ; Humans

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.
Body Water ; Electric Impedance ; Extracellular Fluid ; Humans ; Intracellular Fluid

The maintenance of potassium balance depends primarily on excretion by the kidney. The regulated secretion of potassium normally accounts for most of urinary potassium excretion. Potassium transport along the nephron has two main features:the ubiquitous Na,K-ATPase defines basolateral membranes, whereas site-specific potassium transporters are responsible for the apical transport. Two different cell types mediate secretion and reabsorption of potassium. Principal cells secrete potassium, whereas intercalated cells, especially those belonging to the subfamily of beta-intercalated cells, reabsorb potassium. The factors that stimulate potassium secretion by the principal cells include (1) increased extracellular fluid potassium concentration (2) increased aldosterone and (3) increased tubular flow rate. One factor that decreases potassium secretion is increased hydrogen concentration (acidosis). In situations associated with severe potassium depletion, there is a cessation of potassium secretion and net reabsorption of potassium. It is believed that H,K-ATPase transport mechanism located in the luminal membrane of the cortical and outer medullary collecting duct cells reabsorb potassium in exchange for hydrogen secreted into the tubular lumen.
Acidosis ; Aldosterone ; Extracellular Fluid ; Hydrogen ; Kidney* ; Membranes ; Nephrons ; Phenobarbital ; Potassium*

To define the postnatal changes in ANP secretion in response to mechanical stretch and atrial compliance, experiments have been done in perfused nonbeating rabbit atria with different ages: 1-day, 1-, 2-, 3-, 4-, and 8-wk-old. In 1-day-old-rabbits, an increase in intraatrial pressure resulted in an increase in atrial volume, which was higher than that in 1-wk-old rabbits. Increases in atrial volume stimulated the secretion of ANP with concomitant translocation of extracellular fluid (ECF) into the atrial lumen. However, mechanically stimulated ECF translocation was lower in 1-day-old rabbits than that in 1-wk-old rabbits. Therefore, positive relationship between mechanically stimulated ECF translocation and ANP secretion was shifted upward in 1-day-old rabbits, as compared to 1-wk-old rabbits. Changes in atrial volume and ECF translocation were gradually increased with aging and reached the peak value at 4 wk. The stretch-induced ANP secretion in terms of ECF translocation (the interstitial ANP concentration) was also increased with aging and reached the peak value at 4 wk. The interstitial ANP concentration was dependent on the atrial content of ANP. These data suggest that the higher level of atrial ANP secretion is related to the postnatal changes in atrial volume and unidentified factor.
Aging ; Atrial Natriuretic Factor* ; Atrial Pressure ; Compliance* ; Extracellular Fluid ; Rabbits*

OBJECTIVE: To calculate the imbalance degree (IBD) of left-right meridian (IBD-LRM), IBD of exterior-interior meridian (IBD-EIM) and IBD of hand-foot meridians (IBD-HFM) of impedance in extracellular fluid of cells in twelve meridians of healthy subjects, so as to provide foundation for meridian diagnosis. METHODS: A total of 31 healthy volunteers were enrolled and bioelectrical impedance spectroscopy (BIS) was applied. The constant current (from 1 to 100 kHz, 200 μA) was connected into the bilateral twelve meridians through two excitation electrodes with a distance of 10 cm. Two measuring electrodes, with an interval of 5 cm, were set in between the two excitation electrodes to collect the voltage amplitude and phase. The Cole-Cole curve fitting was used to calculate the impedance of extracellular fluid of cells in the twelve meridians; the IBD-LRM, IBD-EIM and IBD-HFM as well as their absolute values were calculated. RESULTS: The impedance of extracellular fluid in the left side was higher than that in right side in the large intestine meridian, the small intestine meridian and the bladder meridian (<0.05, <0.01). The mean value of IBD-LRM of extracellular fluid was (4.0±1.4) %; the mean value of absolute value of IBD-LRM was (15.0±1.1) %; the maximum absolute value of IBD-LRM was the bladder meridian. The mean value of IBD-EIM was (3.3±1.0) %; the mean value of absolute value of IBD-EIM was (17.9±1.6) %; the maximum absolute value of IBD-EIM was the bladder meridian and the kidney meridian. The impedance of extracellular fluid of hand meridian, hand meridian and hand meridian were lower than those of foot meridians. The mean value of IBD-HFM was (-2.6±1.1) %; the mean value of absolute value of IBD-HFM was (19.7±1.7) %; the maximum absolute value of IBD-HFM was meridian; the imbalance of meridians was greater than meridians. There were significant differences in impedance of extracellular fluid between left and right and between hands and feet (<0.05, <0.01). CONCLUSION The extracellular fluid of left-right meridians of healthy subjects is different, but the absolute value of IBD is low; the mean value of exterior meridian and interior meridian is very close, and the absolute value of IBD is medium; the impedance of the foot meridians are greater than the hand meridians, and the absolute value of IBD is relatively high.
Acupuncture Points ; Electric Impedance ; Extracellular Fluid ; Healthy Volunteers ; Humans ; Meridians

Acupuncture Points ; Acupuncture Therapy ; Cardiovascular System ; Extracellular Fluid ; Humans

Qi, blood and the meridians are fundamental concepts in Chinese medicine (CM), which are components of the human body and maintain physiological function. Pathological changes of qi, blood and meridians may lead to discomfort and disease. Treatment with acupuncture or herbal medicine aims to regulate qi and blood so as to recover normal function of the meridians. This paper explores the nature of qi as well as compares and correlates them with the structures of the human body. We propose a conceptualization of qi as being similar to the interstitial fluid, and the meridians as being similar to interstitial space of low hydraulic resistance in the body. Hence, qi running in the meridians can be understood as interstitial fluid flowing via interstitial space of low hydraulic resistance.
Acupuncture Points ; Connective Tissue ; physiology ; Extracellular Fluid ; physiology ; Extracellular Space ; physiology ; Humans ; Meridians ; Qi ; Water

In hyponatremic patients, the assessment of extracellular fluid volume plays an essential step in diagnosing the etiology of hyponatremia and deciding how to manage it. Although various laboratory tests and diagnostic procedures have been developed for differential diagnosis of hyponatremia, there still are limits to the evaluation of the status of extracellular fluid volume due to the data that overlaps each other, leading to the difficulty in diagnosing between euvolemia and hypovolemia. Also, there is no consensus about how to guide the type and amount of fluid therapy despite many formulas including Adrogue-Madias and Barsoum-Levine formulas have been suggested. Hereby, we are reporting two hyponatremic patients (102 and 105 mEq/L) admitted simultaneously with indistinct volume status on initial clinical and laboratory examinations, but were clarified as euvolemic hyponatremia (syndrome of inappropriate antidiuretic hormone secretion) in one and hypovolemic hyponatremia in the other case after sequential intravenous saline (2 L over 24 hrs) and oral water (20 mL/kg) loading tests. When serum sodium values calculated by the above-mentioned two formulas were compared with actually measured ones during saline loading test in these cases, the Barsoum-Levine formula revealed almost no discrepancy between both the values while the Adrogue-Madias formula underestimated the measured value.
Consensus ; Diagnosis, Differential ; Extracellular Fluid ; Fluid Therapy ; Humans ; Hyponatremia ; Hypovolemia ; Inappropriate ADH Syndrome ; Sodium ; Water