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PubMed2001

Ecophysiological adaptation to salinity throughout a life cycle: a review in homarid lobsters.

Adaptations to salinity are reviewed throughout development in both species of the genus Homarus. Some populations of homarid lobsters are known to inhabit coastal and estuarine areas where salinity fluctuates. Salinity tolerance varies during development, with 50 % lethal salinities (LS(50)) ranging from approximately 15-17 in larvae to approximately 12 in postlarvae and 10 in adults. Larval and adult lobsters can avoid low-salinity areas using behavioural strategies. When exposed to low salinity, the capacity to osmoregulate varies with development. Embryos are osmoconformers and are osmotically protected by the egg membranes. Larvae are also osmoconformers, and the pattern of osmoregulation changes at metamorphosis to hyper-regulation, which is retained throughout the later stages up to the adult stage. Exposure to low salinity increases the activity of Na(+)/K(+)-ATPase in postlarvae and later stages. The level of osmoregulation evaluated through the osmoregulatory capacity (the difference between haemolymph and medium osmolalities) is negatively affected by low temperature (2 degrees C). The variations in haemolymph osmolality resulting from osmoconforming or partial osmoregulation are compensated by intracellular iso-osmotic regulation. Neuroendocrine control of osmoregulation appears in postlarvae and seems to involve the crustacean hyperglycaemic hormone. In adult lobsters, the gills appear to have a respiratory function only, and extracellular osmoregulation is effected by the epipodites, with the addition of the branchiostegites at low salinity. These organs are present at hatching. Transmission electron microscopy and immunolocalization of Na(+)/K(+)-ATPase reveal that the epipodites become functional in larvae and that the branchiostegites become functional in postlarvae. An integrated series of events links the appearance of osmoregulatory tissues, the increase in Na(+)/K(+)-ATPase activity, the occurrence in postlarvae of hyper-regulation at low salinity and the increase in salinity tolerance. Further ecological and physiological studies are proposed for a better understanding of the adaptive significance of the ontogeny of osmoregulation in lobsters.

Adaptation, Physiological↗

PubMed2005

Effects of salinity on copper accumulation in the common killifish (Fundulus heteroclitus).

Results of laboratory and field studies have demonstrated that salinity influences the accumulation of copper. The present study is, to our knowledge, the first to examine the effect of salinity on copper accumulation in a teleost fish across a comprehensive range of salinity from freshwater to seawater. This was done in an effort to identify potential target tissues and differences in chemical interactions across salinities that will aid in the development of a seawater biotic ligand model (BLM) for copper. Killifish (Fundulus heteroclitus) were acclimated to five salinities (0, 5, 11, 22, and 28 ppt) and exposed to three copper concentrations (0 [nominal], 30, and 150 microg L(-1), yielding 15 treatment groups. Fish from each group were sampled for tissue copper analysis at 0, 4, 12, and 30 d postexposure. Whole-body and liver accumulations were highest at lower salinities. The liver accounted for 57 to 86% of the whole-body copper even though it accounted for less than 4% of the body mass. Similarly, the gill accumulated more copper at lower salinities, whereas the intestine generally accumulated more copper at higher salinities. Speciation calculations indicate that CuCO3 likely accounts for much of the accumulation, possibly with some contributions from CuOH+ and Cu(OH)2. The free ion, Cu2+, does not appear to be associated with copper accumulation. However, the differences in physiology and in the concentrations of competing cations across salinities suggest that speciation alone cannot explain accumulation. The present findings may have implications for future development of a BLM for saline environments by identifying potential target tissues.

Animals↗

PubMed1992

Effects of desoxycorticosterone acetate (DOCA) plus saline drinking on gentamicin-mediated nephropathy in rats.

Studies were performed to examine the effect of desoxycorticosterone acetate (DOCA) treatment plus isotonic saline drinking on gentamicin (GM)-mediated nephropathy in rats. GM, 40 mg/kg/day, was subcutaneously injected for 13 days following a 5-week treatment with water drinking or DOCA (10 mg/kg/week) plus saline drinking. Twenty-four hours after the last injection of GM, renal blood flow (RBF) and Cin decreased to approximately 69% and 52% of the control values in water-drinking GM-treated rats, respectively, but was well maintained in DOCA plus saline-drinking GM-treated animals. There was no significant difference in morphologic tubular injury or the renal cortical GM content between GM-treated groups. Saline drinking alone (1% saline, 5 weeks) lessened neither GM-induced reduction in GFR nor tubular damage. Body weight loss occurred following GM injection in the water-drinking group but not in the DOCA plus saline-drinking and saline-drinking-alone groups. DOCA plus saline drinking significantly suppressed the plasma renin activity (PRA) but saline drinking alone did not. A significant inverse correlation was found between PRA and Cin in water-drinking GM-treated and untreated rats. The data suggest that the beneficial effect of DOCA plus saline drinking is associated with renin-angiotensin suppression rather than with the renal GM content or well-maintained hydration.

Acute Kidney Injury↗

PubMed1995

The influence of salinity on the toxicity of various classes of chemicals to aquatic biota.

The objective of this study was to review all available aquatic toxicity literature regarding the effects of salinity on the toxicity of various classes of inorganic and organic chemicals. Toxicity data for studies in which toxicity was assessed at various salinities were organized by chemical classes and trophic groups. Seventy percent of the studies were conducted with either crustaceans or fish. The other 30% were with mollusks, annelids, zooplankton, bacteria, phytoplankton, or fungi. Results from 173 data entries showed that negative correlations (toxicity increasing with decreasing salinity) were reported most frequently (55%), followed by no correlations (27%) and positive correlations (18%). The toxicity of most metals such as cadmium, chromium, copper, mercury, nickel, and zinc was reported to increase with decreasing salinity. This finding is likely related to the greater bioavailability of the free metal ion (toxic form) at lower salinity conditions. There was generally no consistent trend for the toxicity of most organic chemicals with salinity. The one exception to this was reported with organophosphate insecticides, the toxicity of which appeared to increase with increasing salinity. Physiological characteristics of the various test species were important in determining the toxicity of the various classes of chemicals at a range of salinities. Results from various studies showed that euryhaline species were more resistant to toxic conditions at isosmotic salinities due to minimization of osmotic stress. Specific examples showed that fish were more resistant to toxic chemicals at middle salinities when compared with either lower or higher extremes. Life history and ecology of test species were important factors to consider when interpreting salinity/contaminant interaction data.

Animals↗

PubMed2003

Influence of salinity on the physiological conditions in mussels, Perna perna and Perna viridis (Bivalvia: Mytilidae).

Perna genus was introduced to Venezuela, but nowadays, Perna perna and Perna viridis coexist and are commercially exploited from their natural beds. The aim of this work was to determine the effect of salinity on the physiological conditions of these species by studying RNA/DNA and Protein/DNA ratios. The organisms were collected from natural beds at La Esmeralda, Sucre State, Venezuela, and acclimatized for 15 days under laboratory conditions at 25 degrees C, 36 per thousand salinity, pH between 7 and 8 and more than 90% of oxygen saturation. Later, they were divided in two groups: for one group, the salinity concentration was increased (36 to 45 per thousand), and for the other, the salinity was decreased (36 to 15 per thousand). The rate of change was 1 per thousand every day. Ten organisms per group of both species were taken at each of 15, 20, 25, 30, 36, 40 y 45 per thousand salinity concentrations. Protein (colorimetric method) and nucleic acids (RNA and DNA by fluorometric method) concentrations were measured in the digestive gland, gills and adductor muscle tissues. Results indicate that P. perna can physiologically compensate the increase in salinity, but not when the salinity decreased, when proteins are the most needed macromolecules. The Protein/DNA index is directly related to salinity changes in both cases. P. viridis shows physiological compensation to salinity increases and decreases. The RNA/DNA index value in both cases supports this. Digestive gland and muscle tissues are the regulating tissues in both species. These results show that P. viridis has a higher degree of adaptability to salinity changes and, therefore, a greater potential for aquaculture than P. perna.

Adaptation, Physiological↗

PubMed1995

Nebulized bacteriostatic saline as a cause of bronchitis.

BACKGROUND: The purpose of this study was to determine whether nebulized bacteriostatic saline, which contains the preservative benzyl alcohol, is an irritant to the tracheobronchial mucosa in healthy adults. METHODS: A randomized, double-blind, placebo-controlled study was conducted with 10 healthy adults who inhaled 3 mL of either bacteriostatic saline or saline placebo by nebulizer four times a day for 2 weeks. Pulmonary function tests and bronchoscopy with biopsy were performed immediately before and after the 2-week nebulization period. RESULTS: Nine of 10 volunteers were compliant with the study protocol. Four of five volunteers who used nebulized bacteriostatic saline developed bronchitic symptoms and had bronchoscopic evidence of bronchitis. The fifth remained healthy. Four volunteers used nebulized saline (placebo). Two of these four became ill, one with a much more severe bronchitis than any of the bacteriostatic saline volunteers, and one with pharyngitis. Bronchoscopic biopsies showed a lymphocytic mucosal infiltrate in those who became ill while using nebulized bacteriostatic saline and a polymorphonuclear mucosal infiltrate in those who became ill while using nebulized saline placebo. CONCLUSIONS: Nebulization of bacteriostatic saline, containing benzyl alcohol as its preservative, causes bronchitis in healthy adults. Even nebulization of sterile saline may be associated with bronchitis and pharyngitis. Physicians who prescribe nebulized medications must pay close attention to the bronchodilator diluent.

Adult↗

PubMed2024

Decoding the trajectory of antibiotic resistance genes in saline and alkaline soils: Insights from different fertilization regimes.

The soil salinity and alkalinity play an important role in the occurrence and proliferation of antibiotic resistance genes (ARGs). Yet, little is known the underlying mechanism by which soil salinity and alkalinity affect antibiotic resistance evolution. Here we investigated the ARGs variation in soil salinity and alkalinity environments created by different fertilization, and explored the biological mechanisms that salinity and alkalinity alter the evolutionary paradigm of antibiotic resistance. The results showed the soil treated by organic fertilizer exhibited a low salinity, neutral level (TSD 239.20 μS/cm, pH 7.17). The ARG abundance in the OF treatment was the highest, keeping an average of 67.83 TPM. Beside the effect of direct input of organic fertilizer at the beginning, it was important to note that, ARGs abundance during planting showed significant correlations with pH and electric conductivity. We observed that changes in microbial survival strategies under different salinity and alkalinity conditions further affected ARG hosts abundance. Indoor experiments demonstrated that there was a survival trade-off between the growth of resistant bacteria and the evolution of antibiotic resistance in salinity and alkalinity environments. Meta-genomic and Meta-transcriptomic analysis consistently demonstrated bacterial antibiotic resistance was primarily associated with pyruvate, energy and lipid metabolic pathways. The functional gene related to salinity and alkalinity, like cysH, cysK, plsB and plsC showed negative correlations with MDR. Prokaryotic transcription assays validated these relations. This study well explains the prevalence of soil ARGs after different fertilization regimes and will give a deeper understanding for the effect of soil salinity and alkalinity on antibiotic resistance evolution.

Soil↗

PubMed1993

Effects of d-fenfluramine, MK-212, and ondansetron on saline drinking in two-choice tests in the rehydrating rat.

The aim of the present studies was to investigate the effects of serotonergic compounds on preference for isotonic saline and aversion to hypertonic saline, respectively. Twenty-two-hour water-deprived rats were divided into two groups: The first was given a choice between 0.9% saline and water in a 30-min test; the second was given a choice between 1.8% saline and water. Animals were tested following administration of d-fenfluramine, the 5-HT1C receptor agonist 6-chloro-2-(1-piperazinyl)pyrazine (MK-212), and the 5-HT3 receptor antagonist ondansetron. d-Fenfluramine (0.3-3.0 mg/kg) did not reduce 0.9% saline preference; instead, at 0.3 mg/kg there was a significant increase in saline drinking. In contrast, MK-212 (0.3-3.0 mg/kg) abolished the preference for isotonic saline whereas ondansetron (10-100 micrograms/kg) had no effect. d-Fenfluramine and MK-212 reduced hypertonic saline drinking, although at the highest dose for each drug water drinking was also reduced. These data add further to the evidence for an important serotonergic involvement in the control of saline drinking and preference in the rat.

Animals↗

PubMed1993

Hypertonic saline infusion increases plasma norepinephrine concentrations in normal men.

We recently demonstrated in patients with panic disorder that hypertonic saline infusion induces acute panic with the same frequency and intensity as the standard hypertonic sodium lactate infusion. We now report the effects in normal men of hypertonic saline infusion on neuroendocrine systems possibly relevant to panic and anxiety. We administered a 150-min infusion of hypertonic saline (5% sodium chloride) which increased plasma osmolality from 288 +/- 1 to 303 +/- 2 mOsm/kg and produced the appropriate increase of plasma arginine vasopressin (AVP). Plasma norepinephrine (NE) increased substantially during hypertonic saline infusion compared to a normal saline infusion of equal volume and duration. Mean arterial pressure (MAP) also increased and there were significant positive correlations between MAP and NE, but not between MAP and AVP during hypertonic saline infusion. Plasma epinephrine and cortisol did not differ between conditions. Although the pattern of plasma adrenocorticotrophic hormone (ACTH) response differed between hypertonic saline and normal saline conditions, ACTH concentrations did not increase compared to baseline in either condition. These data suggest that hypertonic saline infusion increases sympathetic nervous system activity in normal men.

Adrenocorticotropic Hormone↗

PubMed2005

Physiological responses to hyper-saline waters in sailfin mollies (Poecilia latipinna).

We examined the ionoregulatory physiology and biochemistry of the teleost sailfin molly (Poecilia latipinna), an inhabitant of salt marshes along the gulf coast, during exposure to hyper-saline waters (salinity range 35-95 ppt). Mollies were able to tightly control plasma Na(+) and Cl(-) concentrations and tissue water levels up to 65 ppt, but at higher salinities plasma ion levels began to rise and muscle water content dropped. Still, even at the highest salinity (90 ppt) plasma Na(+) and Cl(-) levels were only 32% and 39%, respectively, above levels at 35 ppt. Drinking rates at 60 ppt climbed 35%, while gut Na(+)/K(+)-ATPase (NAK) activity rose 70% and branchial NAK activity jumped 200%. The relatively small rise in drinking rate, in the face of a more than doubling of the osmotic gradient, suggests that a reduction in branchial water permeability significantly limited water loss and associated salt load. At 80 ppt, a salinity where plasma ion levels just begin to rise, drinking rate rose more rapidly, but gut and gill NAK activity did not, suggesting that mollies employed other pathways (perhaps renal) of salt excretion. At higher salinities, plasma ion levels continued to rise and muscle water content fell slightly indicating the beginnings of internal osmotic disturbances. To evaluate the energetic costs of hyper-salinity on mollies we measured the rate of O(2) consumption and found it rose with salinity, in sharp contrast to virtually all species previously examined. Interestingly, despite higher metabolism, growth was unaffected by hyper-salinity.

Animals↗

PubMed2003

Induction of non-painful and painful intestinal sensations by hypertonic saline: a new human experimental model.

BACKGROUND AND AIMS: To develop a pain model for chemical stimulation of the human gut. METHODS: In a double-blind experimental study 10 subjects with a previously performed sigmoidostomy were randomised to receive injections with either isotonic or hypertonic saline in the colonic mucosa. In the hypertonic experimental arm, 0.1 ml of 0.9%, 2%, 4%, and 6% and 0.2 ml of 2% and 4% saline were given. In the placebo arm, six 0.9% saline injections of the same quantities were given. In a separate experiment 0.8 ml 4% saline was infused into the mucosa by a pump over a period of 2min. The pain intensity was rated on a 0-10 visual analogue scale with 5 as the pain threshold. RESULTS: The hypertonic saline injections resulted in local as well as referred non-painful and painful sensations in 9 out of the 10 subjects. The evoked sensations were mostly described as a smarting sensation with an intensity of median 1 (range 0-5.6) for 0.1 ml 2% saline to median 2.9 (range 0-6.2) for 0.2 ml 4% saline. Seven subjects reported referred sensations to the abdominal skin. Continuous infusion of 4% saline resulted in a consistent sensory response in all subjects, with a median intensity of 4.1 (range 2.1-8.1). This sensory intensity was reproducible in 70% in a retest experiment after median 7 weeks. In the placebo arm a total of 70 isotonic saline injections only resulted in inconsistent, short-lasting non-painful sensations in three subjects. CONCLUSION: The model represents a safe method for direct chemical activation of the sensory endings in the human gut. The model may be used for pharmacological screening of analgesics and for basic investigations in patients suffering from gastrointestinal diseases.

Adult↗

PubMed2003

Agreement in surfactant measurements of sputum induced with hypertonic and normal saline.

OBJECTIVE: The contribution of surfactant to the airway epithelial barrier is increasingly being recognized. Dipalmitoyl phosphatidycholine (DPPC), the major constituent of surfactant, is affected by lung injury. Hypertonic saline-induced sputum is a convenient and reliable method of assessing airway cells and mediators. However, the influence of hypertonic saline on DPPC content of sputum is unknown. In this study the level of DPPC in induced sputum obtained using hypertonic saline is examined and compared with that obtained using normal saline. METHODOLOGY: Sputum was induced on two occasions using nebulized hypertonic saline and normal saline, in 15 well non-smoking adults, in random order on different days. DPPC content (microg/mL of sputum) was measured using a standard spectrophotometric method. RESULTS: The mean of log10 DPPC level in sputum obtained using hypertonic saline was 1.88 microg/mL sputum (95% CI 1.53, 2.13) and that obtained using normal saline was 1.83 (95% CI 1.62, 2.14). The mean difference of the two methods was -0.03 (95% CI -0.27, 0.33). Bland and Altman plot showed an equal distribution around the mean and all points were within the mean +/- 2 SD. CONCLUSION: We conclude that DPPC concentration of sputum can be easily measured in induced sputum and that the use of hypertonic saline does not influence the DPPC levels.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2001

The effect of treatment with albumin, hetastarch, or hypertonic saline on neurological status and brain edema in a rat model of closed head trauma combined with uncontrolled hemorrhage and concurrent resuscitation in rats.

UNLABELLED: In rats subjected to closed head trauma (CHT) plus uncontrolled hemorrhage, giving 0.3 mL of 0.9% saline per 0.1 mL of blood lost did not restore mean arterial blood pressure (MAP) or improve neurological severity score (NSS). In CHT without hemorrhage, giving 20% albumin or 10% hetastarch improved NSS. We hypothesized that these latter treatments would also improve NSS after CHT plus uncontrolled hemorrhage. Rats were randomly assigned to one of seven groups. Experimental conditions were CHT (yes or no), uncontrolled hemorrhage (yes or no), and fluid given to replace blood loss (none; 10% hetastarch, 20% albumin, or 3% saline [0.1 mL per 0.1 mL of blood lost]; or 0.9% saline [0.3 mL per 0.1 mL of blood lost]). NSS (0--25 scale, where 0 = no impairment) was determined at 1, 4, and 24 h, and brain water content was determined at 24 h after CHT. NSS (median +/- range) at 24 h was 11 +/- 6 when no fluid was given; 16 +/- 5 with 10% hetastarch; 14 +/- 5 with 20% albumin; 12 +/- 4 with 3% saline; and 13 +/- 4 with 0.9% saline given (not significant). In addition, brain water content and MAP did not differ among the groups receiving CHT with or without uncontrolled hemorrhage. In our model of CHT plus uncontrolled hemorrhage in rats, giving 10% hetastarch, 20% albumin, 3% saline, or 0.9% saline failed to improve NSS, brain water content, or MAP. IMPLICATIONS: In previous studies of closed head trauma (CHT) without hemorrhage, giving 20% albumin or 10% hetastarch improved neurological severity scores (NSSs). We hypothesized that these treatments also might be beneficial in CHT plus uncontrolled hemorrhage. We found that giving 10% hetastarch, 20% albumin, 3% saline, or 0.9% saline failed to improve NSS, brain water content, or mean arterial blood pressure.

Animals↗

PubMed1996

Burn resuscitation: crystalloid versus colloid versus hypertonic saline hyperoncotic colloid in sheep.

OBJECTIVES: The present study was undertaken to assess the fluid balance and hemodynamic effects during the first 8 hrs of resuscitation in animals with a large body surface area burn, using lactated Ringer's solution, 6% hetastarch, and hypertonic saline dextran. DESIGN: A prospective, blinded, controlled, terminal study, using anesthetized animals. The initial baseline period was followed by scald injury, and three different treatment regimens were administered from coded bags to achieve a physiologic end point. SETTING: University laboratory. SUBJECTS: Eighteen female sheep (35 to 45 kg) were anesthetized with isoflurane. INTERVENTIONS: Test solutions (10 mL/kg of either lactated Ringer's solution, hetastarch, or hypertonic saline dextran) were infused 30 mins after the scald injury at a rate to restore and maintain the baseline oxygen delivery (DO2) value. MEASUREMENTS AND MAIN RESULTS: Cardiovascular hemodynamics, plasma sodium concentration, plasma colloid osmotic pressure, and fluid balance were measured before and after scalding and resuscitation. After the initial 10-mL/kg test solution dose was given, lactated Ringer's solution was infused to achieve the same end point of baseline DO2 for the remainder of the 8 hrs. The scald caused an initial 30% reduction in cardiac output, a 20% reduction in mean arterial pressure, and 10% to 15% increase in hematocrit. All three test solutions restored and maintained baseline DO2 within 1 hr. However, hetastarch and hypertonic saline dextran reduced the net fluid volume over 8 hrs by 48% and 74%, respectively, compared with lactated Ringer's solution. Edema in the burn wound was not affected by treatment, while hypertonic saline dextran reduced edema in nonburned skin compared with both lactated Ringer's solution and hypertonic saline dextran. Plasma colloid osmotic pressure was significantly higher in the hetastarch and hypertonic saline dextran groups. A continuous decrease in plasma sodium concentrations from baseline values (140 to 145 mmol/L) was measured in the lactated Ringer's solution and hetastarch groups (130 to 133 mmol/L) over 8 hrs. Plasma sodium concentrations in the group receiving hypertonic saline dextran were increased (150 to 155 mmol/L) at 4 hrs, but returned toward baseline by 8 hrs. CONCLUSIONS: Net volume loading can be reduced markedly by initial resuscitation of large body surface area burn injury using a colloid (hetastarch), and can be further reduced by use of hypertonic saline colloid. Hyponatremia was apparent in the isotonic crystalloid- and colloid-treated animals, but not in those animals treated with hypertonic saline colloid.

Animals↗

PubMed1999

Vascular permeability increase and plasma volume loss induced by endotoxin was attenuated by hypertonic saline with or without dextran.

Endotoxin given intravenously is known to cause plasma leakage and subsequent loss of circulating plasma volume. Hypertonic saline resuscitation has been successfully applied in hemorrhagic and traumatic shock, but its application for the treatment or prevention of septic or endotoxin shock is less well studied. Our aim was to investigate the effects of endotoxin on plasma leakage in hamsters when administered in two different ways: applied locally to the hamster cheek pouch microcirculation or systemically by i.v. injection. The cheek pouch was studied by intravital microscopy using FITC-labeled dextran as a tracer of plasma leakage. Escherichia coli lipopolysaccharide (LPS) was continuously added into the superfusion buffer of the cheek pouch preparation during 120 min in two control groups (each n = 6) and two further groups (each n = 6) treated with either hypertonic saline (HS) or hypertonic saline and dextran (HSD). Treatment was given as an i.v. injection 0.35 mL NaCl 7.5%/100 g b.w. during 4 min starting 15 min prior to the start of endotoxin application. Endotoxin caused a reversible increase in the number of postcapillary venular leaks with a maximal response at 70 min after start of endotoxin application. The maximal responses were reduced to 36% in the HS-treated and to 37% in the HSD-treated group in comparison to what was seen in the control groups. In the second part of the study endotoxin was given i.v. 0.3 mg/kg to anesthetized hamsters (n = 41) and arterial blood samples were collected at 0, 60, 120, and 180 min after endotoxin injection for measurement of hematocrit and plasma FITC-dextran concentration. Hamsters were divided into seven groups: untreated control group (n = 6); HSC control group given only an i.v. injection of hypertonic saline (n = 6); LPS group given endotoxin 0.3 mg/kg during 1 min (n = 9); HSp group given hypertonic saline (NaCl 7.5%) 10 min prior to i.v. endotoxin (n = 6); HSa group given hypertonic saline 10 min after i.v. endotoxin (n = 6); HSD group given hypertonic saline with dextran 40, 10 min prior to i.v. endotoxin (n = 6); HSD control group given only i.v. hypertonic saline + dextran and no endotoxin (n = 2). Injection of endotoxin caused a significant increase in hematocrit, which was counteracted by hypertonic saline treatment, with or without dextran, probably due to reduced extravasation of plasma in postcapillary venules.

Animals↗

PubMed2006

Hypertonic saline resuscitation prevents hydrostatically induced intestinal edema and ileus.

OBJECTIVE: We have shown that acute edema induced by mesenteric venous hypertension (MV-HTN) impairs intestinal transit and reduces the standardized engineering measures of intestinal stiffness (elastic modulus) and residual stress (opening angle). We hypothesized that hypertonic saline (7.5%) would reverse these detrimental effects of acute edema. DESIGN: Laboratory study. SETTING: University laboratory. SUBJECTS: Male Sprague Dawley rats (270-330 g). INTERVENTIONS: Rats were randomized to five groups: sham, MV-HTN alone, MV-HTN with 4 mL/kg normal saline resuscitation (equal volume), MV-HTN with 33 mL/kg normal saline resuscitation (equal salt), and MV-HTN with 4 mL/kg hypertonic saline. Intestinal edema was measured by wet to dry tissue weight ratio. A duodenal catheter was placed and, 30 mins before death, fluorescein isothiocyanate Dextran was injected. At death, dye concentrations were measured to determine intestinal transit. Segments of distal ileum were hung to a fixed point in a tissue bath and to a force displacement transducer and stretched in increments of 1 mm; we recorded the new length and the corresponding force from the force displacement transducer to determine elastic modulus. Next, two transverse cuts were made yielding a 1- to 2-mm thick ring-shaped segment of tissue which was then cut radially to open the ring. Then the opening angle was measured. MEASUREMENTS AND MAIN RESULTS: MV-HTN, MV-HTN with 4 mL/kg normal saline, and MV-HTN with 33 mL/kg normal saline caused a significant increase in tissue edema and a significant decrease in intestinal transit, stiffness, and residual stress compared with sham. Hypertonic saline significantly lessened the effect of edema on intestinal transit and prevented the changes in stiffness and residual stress. CONCLUSIONS: Hypertonic saline prevented intestinal tissue edema. In addition, hypertonic saline improved intestinal transit, possibly through more efficient transmission of muscle force through stiffer intestinal tissue.

Animals↗

PubMed1990

Haematological, serum electrolyte and blood gas effects of small volume hypertonic saline in experimentally induced haemorrhagic shock.

The effects of treatment with small volume hypertonic (2400 mOsm/litre) and isotonic (300 mOsm/litre) saline on serum electrolyte and biochemical concentrations, haemograms and blood gases were evaluated in 12 horses using a haemorrhagic shock model. Intravascular catheters were placed surgically for sample collection prior to anaesthesia. Controlled haemorrhage was initiated and continued until mean systemic pressure reached 50 to 60 mmHg. Hypertonic or isotonic saline (2 litres) was administered by intravenous infusion and data collected for 2 h. Following haemorrhage, packed cell volume (PCV), haemoglobin, blood glucose concentrations and erythrocyte numbers increased whereas plasma total protein and albumin concentrations decreased. Infusion of hypertonic saline resulted in a further decrease in total protein and albumin concentrations. Glucose concentrations and other haematological variables were unaffected. Isotonic saline administration did not affect electrolyte, total protein or albumin concentrations. Concentrations of sodium and chloride were unaffected by hypotension but increased significantly following hypertonic saline treatment, exceeding normal values during the immediate post treatment period. Serum osmolality increased concurrently. No significant changes in arterial and venous blood gas values were observed with haemorrhage or isotonic saline treatment. A transient decrease in arterial and venous blood pH and a sustained decrease in venous bicarbonate and base excess concentrations occurred following hypertonic saline administration. No significant increases in any serum biochemical concentrations occurred during hypotension or following infusion of either isotonic or hypertonic saline. These results demonstrate that small volume hypertonic saline can be administered safely to horses without producing extreme changes in electrolyte concentrations, blood gases or haematological parameters.

Animals↗

PubMed1999

Both inhaled histamine and hypertonic saline increase airway reactivity in non-sensitised rabbits.

BACKGROUND: Asthmatics react with bronchoconstriction upon a variety of stimuli, i.e. exercise and hypertonic aerosol challenge. We have previously shown that hyperventilation with dry gas in a rabbit model resulted in a change of the ion content of the tracheal wall. This was followed by a hyperreactive response to histamine. OBJECTIVE: We hypothesised that nebulisation with 3.6% hypertonic saline will be accompanied by a hyperreactive response to histamine in a rabbit model. METHODS: Anaesthetised rabbits were given histamine after nebulisation with hypertonic saline. In addition, repeat nebulisation with hypertonic saline was given with or without histamine between these nebulisations. RESULTS: There was a different response to histamine 10 mg x ml(-1) whether hypertonic saline had been given or not (p < 0.001). Histamine nebulisation, given after hypertonic saline, caused an increase from baseline in resistance of 65 +/- 12 cm H(2)O.litre(-1) x s (mean +/- SEM, p < 0. 001) and a decrease in compliance of 2.3 +/- 0.4 ml x cm H(2)O(-1) (p < 0.001). The corresponding values for the control animals were 10 +/- 4 cm H(2)O.litre(-1) x s (n.s.) and 1.7 +/- 0.2 ml x cm H(2)O(-1) (p < 0.001). At a second nebulisation with hypertonic saline, with a histamine challenge 30 min before, the resistance increased from baseline by 35 +/- 10 cm H(2)O x litre(-1) x s (p < 0.01). This was not observed when no histamine had been given between the hypertonic saline nebulisations. CONCLUSIONS: This study in rabbits shows that hypertonic solutions cause an increase in the responsiveness to histamine and that histamine causes an increase in responsiveness to hypertonic saline. This is similar to the response of asthmatics to hypertonic saline.

Aerosols↗