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Hemorrhagic shock in dogs. Comparison of treatment with shed blood alone versus shed blood plus Ringer's lactate: intravascular pressures, cardiac output, oxygen consumption, arteriovenous oxygen differences, extracellular fluid PO2, electrolyte changes, and survival rates.

The purpose of our study of hemorrhagic shock in dogs was to examine the efficacy of adding Ringer's lactate to shed blood replacement in increasing animal rates. The standard Wiggers' hemorrhagic shock technic was used in two groups of ten animals each. Intravascular pressures, cardiac outut, oxygen consumption, arteriovenous oxygen differences, extracellular fluid PO2 and pH, electrolyte changes, and survival rates were determined. There was a positive correlation between changes in cardiac output, central venous oxygen content, and PO2 and extracellular fluid PO2 as measured using subcutaneously implanted Silastic tubing and perforated plastic balls. Four of the dogs that received shed blood alone survived, whereas five of the dogs that received shed blood plus Ringer's lactate survived. This difference was not statistically significant.

Animals↗

Effect of extracellular fluid volume expansion on avian lung fluid balance.

We examined the effects of acute expansion of extracellular fluid volume (ECFV) on lung fluid balance and the ultrastructure of the pulmonary air-blood barrier in chickens (Gallus domesticus). We compared changes in extravascular lung water content (EVLW) to the sum of mean pulmonary capillary blood pressure and plasma protein osmotic pressure (tau c), as a measure of net intravascular filtration pressure (NIFP), produced by graded infusion of avian Ringer's solution. NIFP increased with each volume load largely as a result of decreased tau c resulting in progressive increase in EVLW. Progressive interstitial edema occurred with fluid accumulation restricted to the inter air capillary septa, sparing the gas exchanging regions of the air-blood barrier. This was associated with increased thickness of the septa and increased pulmonary capillary endothelial vesiculation. The effect of increased ECFV on pulmonary hemodynamics and lung fluid balance in Gallus is similar to that in mammals.

Animals↗

Lipoprotein oxidation and induction of ferroxidase activity in stored human extracellular fluids.

It was observed that during the storage of human extracellular fluids at -20 degrees C the azide-inhibitable ferroxidase activity of caeruloplasmin declined, whilst a new azide-resistant ferroxidase activity (ARFA) developed. The literature suggested that storage-induced ARFA might be due to either a poorly defined enzymatic activity of a low density lipoprotein (LDL) or to lipid peroxides formed within the different lipoprotein fractions. To study this further, the major lipoprotein classes were separated from human serum by density gradient centrifugation. After storage of the lipoprotein fractions, it was found that the LDL fraction had the highest specific activity of ARFA and the highest content of lipid peroxidation products, as assessed by diene conjugates. The ARFA of LDL correlated with its content of diene conjugates and TBA reactive material, which initially suggested that the Fe(II) oxidising activity of peroxidase LDL arose from the reduction of peroxides by Fe(II) in the classical reaction between the metal ion and free radical reduction of lipid peroxides. However, steady state kinetic analysis indicated an enzymic role of LDL in Fe(II) oxidation, with lipid peroxides acting as a substrate for the enzyme. These results indicate that LDL may contain a peroxidase activity, catalysing the oxidation of Fe(II) by lipid peroxides, as well as a ferrous oxidase activity where O2 is the oxidising substrate.

Acetylation↗

[An analysis of chemical oxygen demand, carbohydrate, IgG and IgA in extracellular fluid of bacterial plaque].

The chemical oxygen demand (COD) of extracellular plaque fluid was measured by potassium dichromate method. Micro-anthrone method and high performance liquid chromatography were used for measuring the carbohydrate content in the fluid. Immunochemistry system was used for measuring IgG and IgA contents in it. The results showed: (1) a high value of COD was found in the extracellular fluid, and it further increased with sugar-intake; (2) during resting stage, the content of carbohydrate measured by microanthrone method or high performance chromatography was very low, and there was no free glucose, fructose or sucrose; (3) no difference of IgG and IgA contents in plaque fluid between caries active (CA) and caries free (CF) subjects was found.

Adolescent↗

Elevated concentrations of morphine 6-beta-D-glucuronide in brain extracellular fluid despite low blood-brain barrier permeability.

1 This study was done to find out how morphine 6-beta-D-glucuronide (M6G) induces more potent central analgesia than morphine, despite its poor blood-brain barrier (BBB) permeability. The brain uptake and disposition of these compounds were investigated in plasma and in various brain compartments: extracellular fluid (ECF), intracellular space (ICS) and cerebrospinal fluid (CSF). 2 Morphine or M6G was given to rats at 10 mg kg(-1) s.c. Transcortical microdialysis was used to assess their distributions in the brain ECF. Conventional tissue homogenization was used to determine the distribution in the cortex and whole brain. These two procedures were combined to estimate drug distribution in the brain ICS. The blood and CSF pharmacokinetics were also determined. 3 Plasma concentration data for M6G were much higher than those of morphine, with Cmax and AUC 4-5 times more higher, Tmax shorter, and VZf-1 (volume of distribution) and CL f(-1) (clearance) 4-6 times lower. The concentrations of the compounds in various brain compartments also differed: AUC values for M6G were lower than those of morphine in tissue and CSF and higher in brain ECF. AUC values in brain show that morphine levels were four times higher in ICS than in ECF, whereas M6G levels were 125 higher in ECF than in ICS. 4 Morphine entered brain cells, whereas M6G was almost exclusively extracellular. This high extracellular concentration, coupled with extremely slow diffusion into the CSF, indicates that M6G was predominantly trapped in the extracellular fluid and therefore durably available to bind at opioid receptors.

Animals↗

The blood-uterine lumen barrier and exchange between extracellular fluids.

The concept of a blood-tissue barrier defines the rates at which matter exchanges among the vascular and extravascular fluids of the tissue. The remarkably slow rates at which substances such as mannitol (Mr 182) enter uterine fluid from plasma demonstrate the existence of a blood-uterine lumen barrier. Available evidence indicates that the uterine microvascular endothelium and the uterine epithelium behave as lipoid layers interrupted by water-filled channels. Furthermore, both cell layers appear to select actively certain substances over others for exchange with opposing extracellular fluids. In contrast to these similarities, the uterine epithelium and endothelium differ considerably with regard to restrictiveness. For most substances the primary rate-limiting boundary between blood and the uterine lumen is the epithelium. The extracellular fluid compartments of the lumen and endometrium are also influenced by the internalization and release of materials into and out of intracellular compartments including those of the stromal and migratory cells of the endometrium, the epithelium and the developing conceptus. Considerable evidence suggests that the luminal milieu of the developing embryo is created and maintained by the transport and permeability properties of the blood-uterine lumen barrier in conjunction with the cellular activities of the endometrium and embryo. This milieu probably fulfils the informational and nutritional needs of the developing embryo.

Animals↗

Elevated cortical extracellular fluid glutamate in transgenic mice expressing human mutant (G93A) Cu/Zn superoxide dismutase.

Transgenic mice expressing a mutated (G93A) human Cu/Zn superoxide dismutase (SOD1) develop motor neuron pathology and clinical symptoms similar to those seen in patients with amyotrophic lateral sclerosis. Loss of motor neurons is most prominent in lumbar, followed by cervical cord and then brainstem. No significant cell death has been reported in motor cortex. The integrity of the cortical glutamate reuptake systems was evaluated using intracerebral microdialysis and western immunoblot assays for the glutamate transporters GLT-1, GLAST, and EAAC1. The basal extracellular fluid levels of aspartate, glutamate, glutamine, 3,4-dihydroxyphenylacetic acid, and 5-hydroxyindole-3-acetic acid were evaluated by HPLC. The extraction fraction of L-3H]glutamate, corrected with [14C]mannitol, was also evaluated. GLT-1, EAAC1, and GLAST protein levels were determined by semiquantitative chemiluminescence immunoblot of proteins from membrane-enriched fractions. The relative optical density of film was translated into relative protein level by comparison with a standard control mouse. The SOD1 mutant mice demonstrated a significant (p < 0.05) increase in basal levels of extracellular aspartate and glutamate. In addition, when the glutamate extraction fraction was challenged with exogenous unlabeled glutamate (500 microM) by reversed microdialysis, the glutamate extraction fraction in the mutant SOD1 mice was decreased significantly from control levels. The SOD1 mutant mice demonstrated no difference in the cortical protein levels of the glutamate transporter subtypes. This study demonstrates that in areas of no visible pathology and no loss of glutamate transporter proteins, SOD1 mutant mice have elevated extracellular fluid aspartate and glutamate levels and a decreased capacity to clear glutamate from the extracellular space.

3,4-Dihydroxyphenylacetic Acid↗

Detection of soluble P-glycoprotein in culture media and extracellular fluids.

Multidrug resistance (MDR) is a unique phenomenon in cancer patients and is commonly associated with an overexpression of the human MDR gene mdr1, which encodes an energy-dependent Mr 180 kDa membrane bound protein, known as P-glycoprotein. P-glycoprotein serves as a membrane efflux to pump the drugs out of the cancer cells. Western blot analysis, using a newly generated monoclonal antibody F4 which recognizes specifically an extracellular epitope of human MDR1 P-glycoprotein, reveals that soluble P-glycoprotein is detected in the cultured media of viable adriamycin-resistant human ovarian carcinoma 2780AD cells, whereas those of the drug-sensitive parent A2780 cells contain no detectable level of soluble P-glycoprotein. Soluble P-glycoprotein also is detected in extracellular fluids of cancer patients, such as malignant ascites and serum, and is not detectable in serum samples of normal healthy individuals. The Mr of soluble P-glycoprotein is the same as that of membrane bound P-glycoprotein. The presence of soluble P-glycoprotein in extracellular fluids may provide the basis for its use as a quantitative parameter of MDR and as a means to lessen or reverse MDR.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Suppression of glial glutamine release to the extracellular fluid studied in vivo by NMR and microdialysis in hyperammonemic rat brain.

Release of glial glutamine (GLN) to the extracellular fluid (ECF), mainly mediated by the bidirectional system N transporter SN1, was studied in vivo in hyperammonemic rat brain, using (15)N-nuclear magnetic resonance (NMR) to monitor intracellular [5-(15)N]GLN and microdialysis/gradient (1)H-(15)N heteronuclear single-quantum correlation NMR to analyse extracellular [5-(15)N]GLN. GLN(ECF) was elevated to 2.4 +/- 0.2 mm after 4.5 h of intravenous ammonium acetate infusion. The [GLN(i)]/[GLN(ECF)] ratio (i = intracellular) was 9.6 +/- 0.9, compared with 17-20 in normal brain. GLN(ECF) then decreased substantially at t = 4.9 +/- 0.1 h. Comparison of the time-courses of intra- and extra-cellular [5-(15)N]GLN strongly suggested that the observed decrease reflects partial suppression of glial GLN release to ECF. Suppression also followed elevation of GLN(ECF) to 1.9 mM, resulting in a [GLN](i)/[GLN(ECF)] ratio of 8.4, upon perfusion of alpha-(methylamino)isobutyrate which inhibits neuronal uptake of GLN(ECF) mediated by sodium-coupled amino acid transporter (SAT). The results provide first evidence for bidirectional operation of SN1 in vivo, and clarify the effect of transmembrane GLN gradient on glial GLN release at physiological Na(+) gradient. Implications of the results for SN1 as an additional regulatory site in the glutamine/glutamate cycle and utility of this approach for examining the role of GLN in an experimental model of fulminant hepatic failure are discussed.

Animals↗

Regulation of extracellular fluid volume in neonates.

This review summarises mechanisms of control of extracellular fluid volume in the neonatal period. 'Normal' body fluid distribution and methods of its measurement are discussed as well as regulatory mechanisms with particular emphasis on hormonal and renal aspects.

Animals↗

51Cr EDTA determinations of the extracellular fluid volume in hemorrhage: a study with fed and starved rats.

Extracellular fluid volumes have been determined in fed and 24-30 h starved rats, before and after 60 min of hemorrhagic hypotension at 70 mmHg. Bilateral renal vascular ligation was carried out to prevent clearance of the isotope tracer used, 51Cr EDTA. The time taken for a bolus of the tracer to distribute itself in its space, was determined in fed and starved animals after the standard period of hypotension. This was found to be 37 min for fed animals, and 50 min for those which had been starved. When the isotope ECF space was compared before and after hemorrhage in fed animals, it was unchanged, despite an estimated blood volume loss of 39%. The isotope ECF space was reduced 5.5% after hemorrhage in animals which had been starved. It is concluded that fed rats mobilised intracellular fluid to the interstitium in hemorrhage, whereas, starved animals did not. This finding of variable fluid homeostasis is ascribed to the different nutritional status of the animals investigated, and has considerable implications.

Animals↗

Distribution of apomorphine enantiomers in plasma, brain tissue and striatal extracellular fluid.

Steady-state concentrations of apomorphine enantiomers were measured in the extracellular fluid collected from rat brain striatum by microdialysis. The free and total concentrations of both enantiomers were also measured in plasma as well as the total concentrations in different brain regions (striatum, cortex and cerebellum). We noticed no regional difference in the total concentrations of the two enantiomers. The extracellular concentrations were much lower, amounting to 8% for R(-)-apomorphine and 4% for S(+)-apomorphine, of the total brain tissue concentrations. The microdialysis samples contained 12 times more (R(-)-apomorphine and 5 times more S(+)-apomorphine than the free apomorphine measured in plasma. The extracellular concentrations of R(-)-apomorphine (129 +/- 20 pmol/ml) were significantly higher (P = 0.001, n = 6), than those of S(+)-apomorphine (70 +/- 10 pmol/ml). These results indicate that both enantiomers of apomorphine concentrate equally in brain cells, and that a stereoselective uptake system could operate for R(-)-apomorphine at the blood-brain barrier level.

Animals↗

Evidence for amino acid concentration gradients between CSF and extracellular fluid.

A small volume in the extracellular space of the medulla in the anesthetized cat was perfused with cisternal cerebrospinal fluid (CSF) using a push-pull technique. The recovered perfusate was a mixture of pushed CSF and the extracellular fluid. HPLC-EC analysis showed that the concentration of some primary amino acids in recovered perfusate often differed from their concentrations in CSF. These results suggested that amino acid gradients existed between CSF and the extracellular space.

Amino Acids↗

Mechanical control of extracellular space in rabbit atria: an intimate modulator of the translocation of extracellular fluid and released atrial natriuretic peptide.

We have previously shown that extracellular fluid (ECF) is translocated by atrial contraction. Following on from this finding we have proposed a two-step sequential mechanism for the regulation of stretch-activated secretion of atrial natriuretic peptide (ANP): myocytic release of ANP into the surrounding paracellular space followed by the translocation of ECF with the released ANP into the bloodstream. This latter step is induced by atrial contraction, and is therefore controlled by atrial workload. However, the mechanism that regulates the changes in translocation of the ECF has not been defined. To define the relationship between the atrial workload, ECF translocation, size of the extracellular space (ECS) and ANP secretion, experiments have been performed in isolated perfused beating rabbit atria. Atrial workload, transendocardial translocation of the ECF and the secretion of ANP were quantified. Changes in the size of the atrium and the ECS were determined by a newly developed methodology in the beating atria. Atrial workload determined the translocation of the ECF and released ANP with waning of the translocation at higher myocardial workloads. Atrial workload inversely determined the size of the atrium and the ECS. The latter directly determined the translocation of the ECF in terms of atrial workload. From these data we suggest that the size of the ECS is an intimate modulator of the translocation of the ECF and released ANP, and that the phenomenon of waning of the transendocardial translocation that appeared at higher atrial workloads is closely related to the shrinkage of the ECS.

Animals↗

Studies on the reaction between pyridine nucleotides and mercury compounds in artificial intracellular and extracellular fluids.

The strong complex formations of pyridine nucleotides with mercury compounds were demonstrated in artificial intracellular fluid containing oxianions (HPO42-, HCO3-), while those in artificial extracellular fluid were considerably weaker. Dissociation constants (K) of the complexes of [MC.NADP], [MC.NADPH], [MC.NAD], [MC.NADH], [MC.adenine], and [MC.nicotinamide mononucleotide] were found to be 1.0 x 10(-4), 2.6 x 10(-5), 1.2 x 10(-4), 2.9 x 10(-5), 7.2 x 10(-6), and 3.8 x 10(-3), respectively in phosphate buffer (43 mM, pH 8.0).

Extracellular Space↗

Measurement of extracellular fluid volume in the neonate using multiple frequency bio-impedance analysis.

Bioelectrical impedance analysis may be useful for cot-side monitoring of fluid balance in the neonatal intensive care unit (NICU). However the presence of cardio-respiratory monitoring equipment, non-ideal electrode placement and inability to obtain accurate crown-heel measurements may interfere with the ability to obtain reliable impedance data in this setting. This study aimed to investigate the effects of these factors on impedance analysis and to develop a prediction equation for extracellular fluid volume in the neonate. The study found that cardio respiratory monitoring had no significant effect on multi-frequency impedance measurements. Placement of current delivering electrodes on the ventral rather than dorsal surfaces improved separation of current and voltage electrodes but did not alter impedance results. Contralateral measurements were not significantly different to ipsilateral measurements. In 24 infants, extracellular fluid volume was measured using corrected bromide space (CBS) and simultaneous impedance analysis was performed. There was good correlation between CBS and the impedance quotient FF2/Ro where F is foot length and R0 is resistance at zero frequency. The study concludes that despite many potential difficulties associated with impedance analysis in the NICU, reliable measurements of impedance can be obtained and further work to validate prediction equations for ECF is warranted.

Electric Impedance↗

The effects of the production of sodium depletion by peritoneal dialysis with 5 percent glucose on the volume and composition of the extracellular fluid of dogs.

1. The volumes and compositions of the extracellular and peritoneal fluids were monitored in functionally nephrectomized dogs during a period of 4 hr of peritoneal dialysis with 5% glucose.2. The extracellular fluid volume ([(14)C]mannitol space), sodium, potassium and chloride concentrations decreased, while the peritoneal fluid volume, sodium, potassium and chloride concentrations increased.3. Movement of water from the e.c.f. to non-extracellular sites occurred, reaching a maximum after 1 hr; thereafter, the movement of water was first reduced, and later reversed.4. From the volumes and compositions of the extracellular and peritoneal fluids, the total contents of solutes in the two compartments were calculated.5. There was a mobilization of sodium and chloride from non-extra-cellular sites, which became significant after 2 hr of dialysis, and increased throughout the remainder of the period of dialysis.6. The physiological significance of these changes is discussed.

Animals↗

[Clinical application of extracellular fluid measurement using 35S-sodium sulfate (author's transl)].

ECF (extracellular fluid volume) was measured by 35S-sodium sulfate and the same time value of PV (plasma volume) was determined by 131I-RISA in each subject. In normal ECF was an average of 181 ml/kg, 6.21 l/m2 and PV was 49.1 ml/kg, 1.69 l/m2. Both values of ECF and PV in essential hypertension were almost the same as those in normal. In congestive heart failure ECF was 232 ml/kg, 7.51 l/m2 and PV was 55.8 ml/kg, 1.80 l/m2. In the patients with ascites or edema, ECF was 256 ml/kg, 8.69 l/m2 and PV was 53.0 ml/kg, 1.79 l/m2. The results of the measurement by the two compounds also corresponded to the conditions of the patients who showed electrolytes disorders (ACTH deficiency, SIADH) and was improved by treatment.

Adult↗