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At least 19 recordsLinked to original sources
PubMed1986

Energetics and mechanics of frog skeletal muscle in hypotonic solution.

Hypotonic solutions are known to potentiate muscle force production and increase actomyosin ATPase activity in solution. As such, both the rate and amount of ATP hydrolysis should increase during contraction. This was tested indirectly by measuring force and energy liberation in Rana pipiens semitendinosus muscles at 0 degrees C in hypotonic solution. Force and the amount and rate of energy liberation increased. This increase is consistent with the interpretation that the rate of ATP hydrolysis is increased in hypotonic solution. Muscles, stretched to beyond myofilament overlap, liberate a substantial fraction of the energy liberated at maximal myofilament overlap. This energy liberation, the activation heat, is thought to reflect the energy utilized to cycle Ca2+. Hypotonic solution decreased the amplitude and the rate of the activation heat, suggesting that the amount and rate of Ca2+ cycled by the sarcoplasmic reticulum is reduced. Thus in hypotonic solution, force production and the rate of ATP hydrolysis by the cross bridges are potentiated despite an apparent decrease in Ca2+ cycling.

Adenosine Triphosphate↗
PubMed1984

Mechanism of inotropic action by hypotonic solution in the frog atrial muscle.

The effects of hypotonic solution on the mechanical activities and action potential of the bullfrog atrium were investigated. Exposure of muscle to hypotonic solutions (70% of normal solution) produced initially a transient increase in twitch after which twitch declined below the control level. The response is independent of the kinds of salts withdrawn to make the medium hypotonic and of the presence of beta-blocker (5 X 10(-7) M propranolol). The resting potential and the plateau level of action potential were little changed initially. When the twitch declined, a small amount of depolarization and a shortening of action potential duration were observed; however, the plateau level of action potential was not reduced. The initial increase in twitch was not observed, and only the gradual decline of twitch remained in the caffeine containing hypotonic solution. The weight of muscle increased 10% in the hypotonic solution. The resting tension was also increased transiently and then declined to reach a maintained plateau with exposure to hypotonic solution. In the 0-Ca2+ or caffeine containing medium, the transient component of contracture was suppressed but the plateau tension remained. It is suggested that the initial transient increase of twitch by the perfusion of the hypotonic solution was induced by the Ca2+ released from the sarcoplasmic reticulum (SR), and the resultant decline of twitch resulted from the depletion of Ca2+ from the SR and/or from the shortening of action potential duration.

Action Potentials↗
PubMed2005

Slow volume transients in amphibian skeletal muscle fibres studied in hypotonic solutions.

The influence of extracellular hypotonicity on the relationship between cell volume (V(c)) and resting membrane potential (E(m)) was investigated in Rana temporaria skeletal muscle. V(c) was measured by confocal microscope imaging of fibres through their transverse (xz) planes, and E(m) was determined using standard microelectrode techniques. Hypotonic solutions first elicited a rapid increase in fibre volume, DeltaV(R+) that fulfilled expectations of simple osmotic behaviour described in earlier reports. However, this was consistently followed by a slow increase in V(c) (DeltaV(S+)) to 10-15% above osmotic predictions. Longer (>1 h) exposures to hypotonic solutions permitted a subsequent slow decrease in V(c) (DeltaV(S-)), the eventual magnitude of which exceeded that of the preceding DeltaV(S+). Restoration of isotonic conditions elicited a prompt recovery in V(c) that matched simple osmotic predictions and thus left a net change in V(c). Such alterations in V(c) attributable to DeltaV(S+) then gradually reversed, while those due to DeltaV(S-) persisted. Both DeltaV(S+) and DeltaV(S-) persisted under conditions of Cl- deprivation. The depolarization of E(m) that accompanied DeltaV(R+) was consistent with dilution of intracellular [K(+)]. E(m) did not significantly alter during the subsequent DeltaV(S) transients. These empirical features of DeltaV(S+) and DeltaV(S-) were analysed using the quantitative charge-difference model of Fraser and Huang, published in 2004. This attributed the DeltaV(S+) to an electroneutral increase in the effective osmotic activity of normally membrane-impermeant intracellular anions. In contrast, the DeltaV(S-) could only be explained by an efflux of such anions and was accordingly comparable to organic anion-dependent regulatory volume decreases reported in other cell types.

Animals↗
PubMed2002

Human pharmacokinetic study of heated intraperitoneal oxaliplatin in increasingly hypotonic solutions after complete resection of peritoneal carcinomatosis.

PURPOSE: We studied the pharmacokinetics of heated intraoperative intraperitoneal (i.p.) oxaliplatin (LOHP) solution and its safety profile in increasingly hypotonic solutions. This is the first clinical study of i.p. chemohyperthermia with hypotonic solutions. METHODS: Patients with peritoneal carcinomatosis (PC) underwent complete cytoreductive surgery followed by intraoperative i.p. chemohyperthermia (IPCH) with successive dextrose solutions of 300, 200, 150 and 100 mosm/l. LOHP (460 mg/m(2)) was administered in 2 liters of solution/m(2) at an i.p. temperature of 42-44 degrees C for 30 min. IPCH was performed using an open procedure (skin pulled upwards) with a continuous closed circuit. Patients received intravenous leucovorin (20 mg/m(2)) and 5-fluorouracil (400 mg/m(2)) just before IPCH to maximize the effect of LOHP. i.p. plasma and tissue samples were analyzed by means of atomic absorption spectrophotometry. Sixteen consecutive patients with PC of either gastrointestinal or peritoneal origin were treated. The safety of the procedure was studied. RESULTS: Pharmacokinetics: The mean duration of the entire procedure was 7.7 +/- 2.6 h. Half the LOHP dose was absorbed within 30 min at all dose levels. Absorption was not higher with hypotonic solutions than with isotonic solutions. The area under the curve of LOHP in plasma did not increase with decreasing osmolarity of the i.p. solutions. Intratumoral LOHP penetration was high; it was similar to that at the peritoneal surface, and about 18 times higher than that in nonbathed tissues. LOHP penetration was not significantly increased by using hypotonic solutions. SAFETY: There was a very high incidence of unexplained postoperative peritoneal bleeding (50%) and unusually severe thrombocytopenia in the 150 and 100 mosm/l groups. CONCLUSION: Contrary to experimental studies, this clinical study showed no increase in tumoral or systemic penetration of LOHP with i.p. hypotonic solutions (200, 150 or 100 mosm/l) during IPCH. A high incidence of i.p. hemorrhage and thrombocytopenia was observed.

Antineoplastic Agents↗
PubMedDate not supplied

Contractile responses in human umbilical arteries to hyper- and hypotonic solutions.

The effects of hyper- and hypotonic solutions on vascular smooth muscle were studied using helical strips from human umbilical arteries. Hypertonic solutions evoked a biphasic contraction that consisted of early and late contractions. Verapamil or Ca(2+)-free conditions inhibited early contraction induced by tonicity of 340-539 mosm/kg. Under these conditions, late contraction induced by 340-407 mosm/kg was inhibited, whereas contraction induced by 539 mosm/kg was not. Hypotonic solutions evoked a monophasic contraction. Verapamil or Ca(2+)-free conditions inhibited contraction induced by tonicity of 249-266 mosm/kg but not by tonicity of 213 mosm/kg. Hyper- or hypotonicity-induced contractions were not affected by the presence or absence of endothelium. These results suggest that a small increase or decrease in tonicity within the pathophysiological range of osmotic pressure (260-340 mosm/kg) evokes contraction in human umbilical arteries by stimulating calcium influx through voltage-sensitive Ca2+ channels.

Animals↗
PubMed1983

Changes of platelet cell volumes in hypotonic solution.

Changes of platelet cell volumes in hypotonic solution were studied by the use of a new apparatus for cell volume analysis. Continuous mean cell volume analyzer (CMA) is a computerized instrument which continuously counts the mean cell volume and records the results. Moreover, it also shows patterns of expansion or shrinkage. Adequate amounts of platelet rich plasma were added into 0.8 or 0.4% of NaCl solution containing 5mM phosphate buffer. The mean platelet volumes were measured continuously every 2 seconds for 200 seconds. In isotonic solution, platelets changed their volumes little, but in hypotonic solution, the volumes increased for about 20 seconds and then, decreased gradually. Platelet volume expansion ratio and shrinkage ratio were calculated from these patterns. The shrinkage ratio well corresponded to the values of hypotonic shock response measured by spectrophotometry (r = 0.861). Expansion and especially shrinkage ratios decreased during storage, and they were dependent on stored temperature and pH.

Blood Platelets↗
PubMed1994

Tracheal vascular response to hypertonic and hypotonic solutions.

One of the major roles of the upper respiratory mucosa is to humidify inspired air. This function requires the coordinated activity of respiratory epithelium and mucosal vasculature. It has been difficult to study this relationship in vivo. In the present study, we investigated the effects of osmolarity on the vessel diameter of mucosal vessels via a specially constructed chamber that allows direct visualization of the rat trachea microvasculature. With use of an anesthetized and instrumented rat preparation, the luminal surface of the dorsal wall of the trachea was superfused with physiological solutions at 37 degrees C. The osmolarities were varied by removing or adding NaCl or mannitol (200, 290, and 500 mosM). The mucosal vessels dilated when the airway surface was superfused with hypertonic solutions and constricted when superfused with hypotonic solution. The largest changes occurred in the arterioles (51 +/- 5.6 microns diam), which constricted by 10 +/- 2.18 microns (P = 0.0001) when exposed to a 200 mosM solution and dilated by 11 +/- 1.55 microns (P = 0.0001) when exposed to a 500 mosM NaCl-enriched solution. Smaller changes of similar pattern were seen in venules. The changes in vessel diameter were readily reversible upon replacement of the hypo- or hypertonic solutions by an isotonic solution. We conclude that increase or decrease of solution osmolarity on the epithelial surface of the trachea can regulate diameter of mucosal blood vessels.

Animals↗
PubMedDate not supplied

Scientific basis for the use of hypotonic solutions with ultrasonic liposuction.

BACKGROUND: A number of plastic surgeons have advocated using hypotonic solution in ultrasound lipoplasty, theorizing that induced adipocyte swelling increases membrane susceptibility to ultrasonic disruption. Additionally, it has been theorized that potassium increases membrane permeability. This study aimed to determine the effect of solution osmolality on adipocyte diameter, the time course of hypotonic solution action, and the effect of potassium addition on adipocyte diameter. METHODS: Base solutions with three different osmolalities were prepared: normal saline (NS) (154 mOsm/l), 1/2NS (77 mOsm/l), and 1/4NS (38.5 mOsm/l). Each solution was modified to contain 0, 5, and 10 mEq/l of potassium and adjusted to starting osmolality. Adipocytes of six patients were suspended in the nine solutions, and diameters were determined at 0, 15, 30, and 45 min. Diameters were measured using imaging software (Kodak ID 3.6). RESULTS: At time 0, the average adipocyte diameter was 79 +/- 8 microm, and no difference was seen in any of the solutions. Cells in the NS group showed no significant increase in diameter over 45 min. The 1/2NS group achieved an 8% +/- 1.9% increase in diameter at 45 min (p < 0.05). The 1/4NS group showed an increase by 14% +/- 2.4% (p < 0.01) at 15 min, and 15% +/- 2.3% (p < 0.01) at 45 min. Potassium had no independent effect on cell diameter. CONCLUSIONS: Hypotonic solution can significantly increase human adipocyte diameter. The findings showed that 1/2NS had a significant effect within 15 min. Tumescent solutions with an osmolality of 1/4NS may be useful in facilitating ultrasonic lipoplasty.

Adipocytes↗
PubMed2006

Endothelial cell density in porcine corneas after exposure to hypotonic solutions.

PURPOSE: To evaluate exposure to sucrose solution (1.8%) and hypotonic balanced salt solution (BSS) for its effects on endothelial cell density of porcine corneas. METHODS: Two groups of central discs from pig corneas were organ-cultured for 24 h. Twelve corneas per group were exposed to sucrose solution (1.8%) or hypotonic BSS for 4 min each. The paired corneal discs were not treated and served as controls. After further organ culture with and without dextran for 48 h, corneal endothelium was stained with alizarin red and examined by light microscopy. The endothelial cell densities were determined manually on three central images. RESULTS: The endothelial cell density differed significantly between corneas exposed to sucrose and the control corneas (3982+/-382 cells/mm(2) and 4360+/-331 cells/mm(2) respectively, and 3876+/-364 cells/mm(2) versus 4374+/-168 cells/mm(2) respectively with 6% dextran). In contrast, the endothelial cell density did not differ significantly between corneas exposed to hypotonic BSS and the control corneas (4374+/-296 cells/mm(2) and 4317+/-193 cells/mm(2) respectively, and 4348+/-151 cells/mm(2) versus 4426+/-175 cells/mm(2), respectively with 6% dextran). CONCLUSIONS: Exposure to 1.8% sucrose for 4 min induces a significant endothelial cell loss of 10% on average, whereas exposure to hypotonic BSS did not significantly influence the endothelial cell density.

Acetates↗
PubMed1992

Hypotonic solutions induce epithelium-dependent relaxation of isolated canine bronchi.

The present study was designed to investigate the effect of changes in osmolarity on the modulatory role of the respiratory epithelium on the underlying smooth muscle. Canine bronchial segments with or without epithelium were perfused intraluminally with modified Krebs-Ringer bicarbonate solution. The transluminal isometric tension was recorded by means of stirrups passed through the bronchial wall. During contractions to extraluminal carbachol, the tissues with epithelium exhibited epithelium-dependent relaxations to hypotonic solution given intraluminally. The level of relaxation was dependent on the osmotic pressure. No significant difference was noted between relaxations due to hypotonic solution made by mixing the Krebs-Ringer solution with distilled water and those made by decreasing the concentration of sodium chloride. The epithelium-dependent relaxations could not be blocked by the antagonists or blockers of cyclo-oxygenase, endothelium-derived relaxing factor, alpha-adrenoceptors, beta-adrenoceptors, and sodium channels. No evidence for the release of a relaxing factor into the bronchial lumen was found in bioassay study. When the preparation was stimulated with hypertonic solutions prepared by adding mannitol or urea, similar relaxations were induced in tissues with and without epithelium. These observations suggest that changes in osmolarity affect the responses of canine bronchi to carbachol and that the epithelium modulates the responses of airway to hypotonic solutions.

Airway Resistance↗
PubMed1999

Administration in a hypotonic solution is preferable to dose escalation in intraperitoneal cisplatin chemotherapy for peritoneal carcinomatosis in rats.

An animal model of intraperitoneal (i.p.) cisplatin chemotherapy using hypotonic solutions of sodium chloride has been developed as a treatment for peritoneal carcinomatosis. The concentrations of platinum in the plasma and in the i.p. fluid of Donryu rats were measured after i.p. injection of hypotonic (103 or 154 mosm/l) and isotonic (308 mosm/l) solutions that contained an equal amount of cisplatin. The maximum concentration (Cmax) and the area under the curve of concentration versus time (AUC) of platinum in the plasma increased proportionately with increases in the dose of cisplatin and they were significantly higher in rats given cisplatin in hypotonic solutions than in those given the drug in isotonic solution. The Cmax and AUC of total platinum were similar for the solution of 103 mosm/l with 2.5 mg/kg cisplatin and the isotonic solution with 5.0 mg/kg cisplatin. The Cmax and AUC of free platinum in the plasma did not increase with increases in the dose of cisplatin in isotonic solution but did increase after hypotonic injection. However, the solutions of lower osmolarity gave a decreased AUC of platinum in the i.p. fluid. Hypotonic conditions continued for 30 min at most after i.p. injection of hypotonic solutions. When the same dose of cisplatin was given to rats with tumors derived from AH100B carcinoma cells, the amount of platinum taken by i.p. solid tumors from the solution of 103 mosm/l was about twice that from the isotonic solution and was much the same as that taken up from the isotonic solution with twice the amount of cisplatin. These results indicate that hypotonic i.p. cisplatin chemotherapy might be preferable to escalation of the dose of i.p. cisplatin in the treatment of peritoneal carcinomatosis.

Animals↗
PubMed1998

Facilitation of gastric motility induced by portal infusion of hyper- and hypotonic solution in rats.

The effects of the portal infusion of hyper- and hypotonic solution on gastric motility in rats were investigated. The infusion of hypertonic saline into the portal vein (portal infusion) elicited a significant enhancement of gastric contractile activity. The portal infusion of water also produced this enhancement. However, the portal infusion of isotonic saline showed no significant enhancement; nor did the infusion of water and hypertonic saline into the jugular vein. Sectioning of the hepatic branch of the vagus nerve (hepatic vagus) eliminated the enhanced responses of the gastric motility. It is therefore concluded that hepatoportal osmoreceptive afferent signals affect the gastric motility by way of the hepatic vagus. These effects on osmolarity revealed that hypotonic stimulation is more effective than hypertonic stimulation for the enhancement of motility. Sectioning of the dorsal subdiaphragmatic vagus, which includes the dorsal gastric and celiac branch, did not eliminate these responses. Sectioning of the ventral gastric vagus, in contrast, did eliminate the responses. These results suggest that vagal preganglionic neurons in the left dorsal motor nucleus of the vagus play a role in enhancement of gastric motility observed in the present research.

Animals↗
PubMed2002

Rapid, sensitive diagnosis of hemolytic anemia using antihemoglobin antibody in hypotonic solution.

We have developed a new and simple flow cytometric method to detect damaged red blood cells (RBCs) using anti-Hb in hypotonic solution. We studied a total of 200 patients, including 62 patients with schistocytosis, 8 postsplenectomy patients, and 108 healthy controls. Peripheral blood (2 microl) was stained with phycoerythrin-conjugated (PE) antihemoglobin antibody (anti-Hb) in 0.6% (w/v) NaCl solution, and analyzed by flow cytometry omitting the washing step. The proportion of RBCs stained by anti-Hb was 0.55% (SD +/-0.23%) in normal controls and was significantly higher in patients with schistocytosis (2.95+/-2.95%, p <0.001). Six of 108 blood samples from normal controls and 60 of 62 samples from schistocytosis patients showed > or =1.01% stained RBCs (ie, values > mean+2SD of normal controls). The number of schistocytes counted by microscopic examination correlated with the proportion of RBCs stained by anti-Hb (r = 0.637, p <0.001). The proportions of stained RBCs in blood samples with malaria, spherocytosis, and elliptocytosis were also significantly higher than in normal controls. However, the results in postsplenectomy and iron-deficiency anemia (IDA) patients were not significantly different from the normal controls; the number of schistocytes in postsplenectomy patients was not related to the proportion of RBCs stained by anti-Hb. Based on these findings, flow cytometry of damaged RBCs using anti-Hb in hypotonic solution is a simple, sensitive, and accurate method to detect active hemolysis.

Anemia, Hemolytic↗