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PubMed1991

A comparison of the cerebral and hemodynamic effects of mannitol and hypertonic saline in a rabbit model of acute cryogenic brain injury.

There has recently been an increased interest in the use of hypertonic saline solutions in the fluid resuscitation of trauma victims and patients with uncontrollable intracranial hypertension. In this study, the cerebral and hemodynamic effects of 3.2% hypertonic saline solution were compared with those of an equiosmolar (20%) mannitol solution or 0.9% saline in a rabbit model of acute cryogenic brain injury. Forty-five minutes following the creation of a left hemispheric cryogenic brain lesion, equal volumes (10 ml/kg) of hypertonic saline, 0.9% saline, or mannitol were infused over a 5-min period. Monitored variables over the ensuing 120 min included mean arterial pressure, central venous pressure, intracranial pressure (ICP), hematocrit, and serum osmolality. At the conclusion of the 2-h study period, hemispheric water contents were determined by gravimetric analysis and the wet/dry weight method. There were no significant differences in mean arterial pressure between the three groups at any time during the experiment. Plasma osmolality was significantly increased by +/- 10 mOsm/kg following infusions in both the mannitol and hypertonic groups compared to the saline group. The infusion of either mannitol or hypertonic saline produced a transient and significant decrease in ICP during the first 60-90 min but not at 120 min after cryogenic brain lesion, whereas animals in the saline group demonstrated a continual increase in ICP. However, there appeared to be no significant differences in ICP between animals receiving mannitol or hypertonic saline at any time point following infusion of solutions. We conclude that following acute cryogenic brain injury, infusions of equal volumes of equiosmolar solutions of hypertonic saline or mannitol will transiently reduce ICP as compared to equal volumes of normal saline. However, hypertonic saline is not superior to mannitol in its ability to reduce ICP in this model of intracranial hypertension.

Journal Article↗

PubMed2006

Regulation of photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat (Camargue, France) by irradiance, temperature and salinity.

Short-term effects of irradiance (0-1560 micromol photons m(-2) s(-1)), temperature (10-25 degrees C), and salinity (40-160) on oxygenic photosynthesis and oxygen consumption in a hypersaline mat (Salin-de-Giraud, France) were investigated with microsensors under controlled laboratory conditions. Dark O(2) consumption rates were mainly regulated by the mass transfer limitations imposed by the diffusive boundary layer. Areal rates of net photosynthesis increased with irradiance and saturated at irradiances >400 micromol photons m(-2) s(-1). At low irradiances, oxygen consumption increased more strongly with temperature than photosynthesis, whereas the opposite was observed at saturating irradiances. Net photosynthesis vs. irradiance curves were almost unaffected by decreasing salinity (100 to 40), whereas increasing salinities (100 to 160) led to a decrease of net photosynthesis at each irradiance. Dark O(2) consumption rates, maximal gross and net photosynthesis at light saturation were relatively constant over a broad salinity range (60-100) and decreased at salinities above the in situ salinity of 100. Within the range of natural variation, temperature was more important than salinity in regulating photosynthesis and oxygen consumption. At higher salinities the inhibitory impact of salinity on these processes and therefore the importance of salinity as a regulating environmental parameter increased, indicating that in more hypersaline systems, salinity has a stronger limiting effect on microbial activity.

Adaptation, Physiological↗

PubMedDate not supplied

Sources of salinity in ground water from Jericho area, Jordan Valley.

One of the major problems in the lower Jordan Valley is the increasing salinization (i.e., chloride content) of local ground water. The high levels of salinity limit the utilization of ground water for both domestic and agriculture applications. This joint collaborative study evaluates the sources and mechanisms for salinization in the Jericho area. We employ diagnostic geochemical fingerprinting methods to trace the potential sources of the salinity in (1) the deep confined subaquifer system (K2) of Lower Cenomanian age; (2) the upper subaquifer system (K1) of Upper Cenomanian and Turonian ages; and (3) the shallow aquifer system (Q) of Plio-Pleistocene ages. The chemical composition of the saline ground water from the two Cenomanian subaquifers (K1 and K2) point to a single saline source with Na/Cl approximately 0.5 and Br/Cl approximately 7 x 10(-3). This composition is similar to that of thermal hypersaline spring that are found along the western shore of the Dead Sea (e.g., En Gedi thermal spring). We suggest that the increasing salinity in both K1 and K2 subaquifers is derived from mixing with deep-seated brines that flow through the Rift fault system. The salinization rate depends on the discharge volume of the fresh meteoric water in the Cenomanian Aquifer. In contrast, the chemical composition of ground water from the Plio-Pleistocene Aquifer shows a wide range of Cl- (100-2000 mg/L), Na/Cl (0.4-1.0), Br/Cl (2-6 x 10(-3)), and SO4/Cl (0.01-0.4) ratios. These variations, together with the high SO4(2-), K+, and NO3- concentrations, suggest that the salinity in the shallow aquifer is derived from the combination of (1) upconing of deep brines as reflected by low Na/Cl and high Br/Cl ratios; (2) leaching of salts from the Lisan Formation within the Plio-Pleistocene Aquifer, as suggested by the high SO4(2-) concentrations; and (3) anthropogenic contamination of agriculture return flow and sewage effluents with distinctive high K+ (80 mg/L) and NO3- (80 mg/l) contents and low Br/Cl ratios (2 x 10(-3)). Our data demonstrates that the chemical composition of salinized ground water can be used to delineate the sources of salinity and hence to establish the conceptual model for explaining salinization processes.

Bicarbonates↗

PubMed1996

The glomerular filtration rate during pregnancy: saline infusion enhances the glomerular filtration rate in the pregnant rat.

The glomerular filtration rate (GFR) of pregnant rats is generally believed to exceed non-pregnant values. This notion is primarily based upon standard insulin clearances. However, the insulin clearance requires continuous infusion of insulin usually dissolved in saline. Since saline infusion per se in pregnancy may influence the GFR, in the present study the effect of saline infusion upon the GFR in pregnant as compared with cyclic rats was investigated using various methods. The standard insulin clearance was compared using the standard 51Cr-EDTA method which does not require saline infusion. Clearance of insulin dissolved in glucose (5% in distilled water) instead of saline was also tested, while the 51Cr-EDTA method was employed using additional fluid infusion with either saline or 5% glucose in distilled water in an identical manner as compared with the insulin method. The GFR was also studied in conscious rats using 51Cr-EDTA clearance with and without fluid infusion. The distribution volume of 51Cr-EDTA was measured in nephrectomized rats (pregnant and cyclic) with and without saline or glucose infusions. The results show a significant increase of the GFR in pregnant rats as compared with cyclic rats only when saline was infused during the measurement; thus, GFR measurements without fluid infusion or replacement of saline by glucose during the measurements did not show a significant increase of GFR in pregnant rats. The volume of distribution per gram body weight of 51Cr-EDTA after saline infusion, but not after glucose infusion, was significantly increased as compared with the values obtained without additional infusion. It is concluded that the increase of the GFR seen in pregnant rats when either the 51Cr-EDTA method or the insulin method is accompanied by saline loading is rather due to infusion of saline in the pregnant animal and not a result of the pregnant condition per se.

Animals↗

PubMed2006

Response of biotic communities to salinity changes in a Mediterranean hypersaline stream.

BACKGROUND: This study investigates the relationship between salinity and biotic communities (primary producers and macroinvertebrates) in Rambla Salada, a Mediterranean hypersaline stream in SE Spain. Since the 1980's, the mean salinity of the stream has fallen from about 100 g L(-1) to 35.5 g L(-1), due to intensive irrigated agriculture in the watershed. Furthermore, large dilutions occur occasionally when the water irrigation channel suffers cracks. RESULTS: Along the salinity gradient studied (3.5-76.4 g L(-1)) Cladophora glomerata and Ruppia maritima biomass decreased with increasing salinity, while the biomass of epipelic algae increased. Diptera and Coleoptera species dominated the community both in disturbed as in re-established conditions. Most macroinvertebrates species found in Rambla Salada stream are euryhaline species with a broad range of salinity tolerance. Eight of them were recorded in natural hypersaline conditions (approximately 100 g L(-1)) prior to important change in land use of the watershed: Ephydra flavipes, Stratyomis longicornis, Nebrioporus ceresyi, N. baeticus, Berosus hispanicus, Enochrus falcarius, Ochthebius cuprescens and Sigara selecta. However, other species recorded in the past, such as Ochthebius glaber, O. notabilis and Enochrus politus, were restricted to a hypersaline source or absent from Rambla Salada. The dilution of salinity to 3.5-6.8 g L(-1) allowed the colonization of species with low salininty tolerance, such as Melanopsis praemorsa, Anax sp., Simulidae, Ceratopogonidae and Tanypodinae. The abundance of Ephydra flavipes and Ochthebius corrugatus showed a positive significant response to salinity, while Anax sp., Simulidae, S. selecta, N. ceresyi, N. baeticus, and B. hispanicus showed significant negative correlations. The number of total macroinvertebrate taxa, Diptera and Coleoptera species, number of families, Margalef's index and Shannon's diversity index decreased with increasing salinity. However, the rest of community parameters, such as the abundance of individuals, evenness and Simpson's index, showed no significant response to changes in salinity. Classification and ordination analysis revealed major differences in macroinvertebrate community structure between hypersaline conditions (76.4 g L(-1)) and the rest of the communities observed at the lower salinity levels, and revealed that below approximately 75 g L(-1), dissimilarities in the communities were greater between the two habitats studied (runs and pools) than between salinity levels. CONCLUSION: Salinity was the first factor determining community composition and structure in Rambla Salada stream followed by the type of habitat.

Journal Article↗

PubMed1994

MECHANISM OF THE NET UPTAKE OF WATER IN MOULTING BLUE CRABS (CALLINECTES SAPIDUS) ACCLIMATED TO HIGH AND LOW SALINITIES

Blue crabs (Callinectes sapidus Rathbun) acclimated to a salinity of 2 approximately doubled in wet mass (excluding carapace) during the period from 10 h before moult to 2 h after moult. Both in blue crabs acclimated to 2 salinity and in crabs acclimated to 28 salinity, the drinking rate increased from approximately 0.4 ml 100 g-1 h-1 at 1 day prior to moult to approximately 8 ml 100 g-1 h-1 during the first hour after moult. The drinking rate had decreased 1 day after moult in both salinities, but was significantly higher in crabs acclimated to high salinity (1.84±0.16 ml 100 g-1 h-1) than in crabs acclimated to low salinity (0.26±0.04 ml 100 g-1 h-1). Drinking accounted for two-thirds of the weight gain during the first hour after moult at both acclimation salinities, indicating that water enters the body at moult primarily through the gut rather than through the gills. [14C]polyethylene glycol, added as a tracer in the bath water, was concentrated in the midgut gland rather than in the stomach, implicating the midgut gland as the primary site of water absorption. The rate of water efflux was significantly greater in crabs acclimated to 30 salinity (66.4±9.0 ml 100 g-1 h-1) than in crabs acclimated to 2 salinity (34.0±4.7 ml 100 g-1 h-1). The osmotic uptake of water is equal at both salinities as a result of the decreased water permeability at low salinity. The rate of urine formation was estimated to be between 0.5 and 1 ml 100 g-1 h-1 during the first hour after moult in crabs acclimated to both low and high salinities, suggesting that the antennal gland plays a relatively small role in water regulation during this period.

Journal Article↗

PubMed2005

Phenol-containing saline solution as a diluent for adenosine 5'-monophosphate in bronchial challenge testing.

OBJECTIVES: To investigate the effect of dissolving adenosine 5'-monophosphate (AMP) with phenol-containing saline solution on the stability and the bronchoconstrictive properties of this indirect agonist. METHODS: Eleven subjects with asthma well controlled with short-acting inhaled beta2-agonists as required or with inhaled corticosteroids were studied. Bronchial challenge tests with AMP dissolved with either normal saline solution or saline solution containing 0.4% phenol were performed on separate days. Furthermore, to assess the potential influence of the phenol-containing saline solution on the stability of the bronchoconstrictor agent, AMP solutions in concentrations of 40 microg/mL and 400 microg/mL were prepared in saline solution and phenol-containing saline solution and, after 30 min, the AMP levels were determined by high-performance liquid chromatography (HPLC) assay. RESULTS: The geometric mean AMP provocative concentration causing a 20% fall in FEV1 (PC20) was 13.49 mg/mL (95% confidence interval [CI], 6.76 to 26.91) for the saline solution method, and AMP PC20 for the saline solution with phenol method was 8.91 mg/mL (95% CI, 3.39 to 23.44) [p = 0.18]. No significant differences were found between the concentrations of AMP made in saline solution compared to those made in phenol-containing saline solution measured by HPLC. CONCLUSION: These observations indicate that normal saline solution with or without phenol can be used as the diluent for AMP. However, since a potential risk with AMP of industrial sources is the bacterial contamination, adding a preservative such as phenol to a saline solution diluent might be recommended.

Adenosine Monophosphate↗

PubMed2004

Respiratory and metabolic effects of massive administration of isotonic saline solution in heaves-affected and control horses.

REASONS FOR PERFORMING STUDY: It has been suggested that rapid administration of isotonic saline solution relieves airway obstruction in heaves-affected horses, but the efficacy and tolerability of this treatment is poorly documented. OBJECTIVES: To determine the respiratory and metabolic effects of a rapid administration of isotonic saline solution in control horses and those with heaves. METHODS: Thirty litres isotonic saline solution were administered i.v. to 5 control (Group C) and 9 heaves-affected horses (Group H). Pulmonary function testing and arterial blood gas analysis were performed prior to saline infusion, at 90 and 180 mins after starting the infusion, and 1, 3, 6 and 10 days later. PCV, plasma total solids, plasma electrolytes (Na+, Cl- and K+) and venous blood gas analysis were performed prior, during and after saline infusion. RESULTS: Rapid saline administration was shown to have no beneficial effects on lung function during infusion in Group H. On the contrary, they had significantly increased pulmonary resistance (RL) at 180 mins following the initiation of saline administration compared to baseline. In Group C, saline administration resulted in a significant increase in RL at 180 mins and a significant decrease in PaO2 at 90 mins. These results suggest a transient decrement in lung function caused by rapid saline administration. Group H had a metabolic alkalosis with hypochloraemia at baseline compared to control horses. This resolved following i.v. saline administration and returned to baseline within 6 h after treatment had been discontinued. CONCLUSION: The administration of saline to Group H did not improve airway function significantly, but resulted in mild and transient side effects. POTENTIAL RELEVANCE: Rapid administration of isotonic saline alone is not an effective therapy for heaves in horses.

Acid-Base Equilibrium↗

PubMed2006

Salinity effects on viability, metabolic activity and proliferation of three Perkinsus species.

Little is known regarding the range of conditions in which many Perkinsus species may proliferate, making it difficult to predict conditions favorable for their expansion, to identify conditions inducing mortality, or to identify instances of potential cross-infectivity among sympatric host species. In this study, the effects of salinity on viability, metabolic activity and proliferation of P. marinus, P. olseni and P. chesapeaki were determined. Specifically, this research examined the effects of 5 salinities (7, 11, 15, 25, 35 per thousand), (1) without acclimation, on the viability and metabolic activity of 2 isolates of each Perkinsus species, and (2) with acclimation, on the viability, metabolic activity, size and number of 1 isolate of each species. P. chesapeaki showed the widest range of salinity tolerance of the 3 species, with high viability and cell proliferation at all salinities tested. Although P. chesapeaki originated from low salinity areas (i.e. <15 per thousand), several measures (i.e. cell number and metabolic activity) indicated that higher salinities (15, 25 per thousand) were more favorable for its growth. P. olseni, originating from high salinity areas, had better viability and proliferation at the higher salinities (15, 25, 35 per thousand). Distinct differences in acute salinity response of the 2 P. olseni isolates at lower salinities (7, 11 per thousand), however, suggest the need for a more expansive comparison of isolates to better define the lower salinity tolerance. Lastly, P. marinus was more tolerant of the lower salinities (7 and 11 per thousand) than P. olseni, but exhibited reduced viability at 7 per thousand, even after acclimation.

Animals↗

PubMed2001

[Ecophysiological adaptability of tropical water organisms to salinity changes].

Physiological response of tropical organisms to salinity changes was studied for some marine, estuarine and freshwater fishes (Astyanax bimaculatus, Petenia karussii, Cyprinodon dearborni, and Oreochromis mossambicus), marine and freshwater crustaceans (Penaeus brasiliensis, Penaeus schmitti and Macrobrachium carcinus), and marine bivalves (Perna perna, Crassostrea rhizophorae, and Arca zebra) collected from Northeast Venezuela. They were acclimated for four weeks at various salinities, and (1) placed at high salinities to determine mean lethal salinity, (2) tested by increasing salinity 5@1000 per day to define upper lethal salinity tolerance limit, or (3) observed in a saline gradient tank to determine salinity preference. Acclimation level was the most significant factor. This phenomenon is important for tropical aquatic organisms in shallow waters, where they can adapt to high salinity during the dry season and cannot lose their acclimation level at low salinity during abrupt rain. For saline adaptation of tropical organisms, this behavior will contribute to their proliferation and distribution in fluctuating salinity environments.

Adaptation, Physiological↗

PubMed2026

Randomised, Multicentre Clinical Trial Found That Hypertonic Saline Did Not Reduce the Length of Stay of Hospitalised Patients With Acute Bronchiolitis.

AIM: Bronchiolitis is a major cause of hospitalisation in young children, but the effectiveness of inhaled hypertonic saline remains unclear. We compared treating hospitalised infants with nebulised hypertonic saline or normal saline. METHOD: This multisite, double-blind RCT was conducted from 1 October 2023 to 1 April 2025 in four Polish paediatric units. Children from 5 weeks to 24 months, who had been hospitalised with mild-to-moderate bronchiolitis, were randomly assigned to receive nebulised 3% hypertonic saline or 0.9% normal saline until discharge. They were followed for 7 days. RESULTS: The study comprised 181 children (55% male) with a mean age of 8.3 ± 6.3 months: 90 were randomised to hypertonic saline and 91 to normal saline. The median hospital stay was 2.68 (1.92-4.03) days in the hypertonic saline group and 2.79 (1.8-3.96) days in the normal saline group. The mean difference was -0.11 days (95% confidence interval -0.73 to 0.12, p = 0.3). No differences were observed in clinical severity scores between the groups. Readmissions only occurred in the normal saline group (5.9%). CONCLUSION: Hypertonic saline inhalation did not reduce the length of hospital stay or improve clinical severity scores in hospitalised children with bronchiolitis, but it was associated with a lower risk of rehospitalisation.

Humans↗

PubMed2004

Effects of buffered saline solution on nasal mucociliary clearance and nasal airway patency.

OBJECTIVE: To compare the effects of buffered hypertonic and buffered normal saline nasal spray on mucociliary clearance and nasal airway patency. STUDY DESIGN AND SETTING: Double-blind trial with subjects acting as their own controls. Tertiary care academic medical center. RESULTS: Buffered hypertonic saline and buffered normal saline both improved saccharine clearance times ( P < 0.0001 for buffered hypertonic and P = 0.002 for buffered normal saline). Buffered hypertonic saline improved saccharine clearance times more than buffered normal saline (39.6% vs 24.1%, P = 0.007). Neither buffered hypertonic nor buffered normal saline significantly affected nasal airway patency. CONCLUSIONS: Both buffered hypertonic and buffered normal saline nasal spray significantly improved saccharine clearance times without affecting nasal airway patency. Buffered hypertonic saline affected saccharine clearance times to a greater degree than buffered normal saline. CLINICAL SIGNIFICANCE: Buffered hypertonic and buffered normal saline sprays both improve mucociliary clearance and should therefore be beneficial in conditions such as rhinitis and sinusitis, which are associated with disruption of mucociliary clearance. However, these sprays do not appear to affect the nasal airway. Patients may therefore benefit from other treatments for "nasal congestion." EBM RATING: B-2.

Administration, Intranasal↗

PubMed1995

Cross refractoriness between bradykinin and hypertonic saline challenges in asthma.

BACKGROUND: Repeated inhalation of bradykinin and hypertonic saline leads to refractoriness of the bronchoconstrictor response in asthma. It is not known whether cross-refractoriness exists between these stimuli. OBJECTIVE: We postulated that repeated bradykinin and hypertonic saline bronchial challenges might reduce the airway response to subsequent hypertonic saline and bradykinin challenges, respectively. METHODS: Eleven atopic asthmatic subjects underwent two concentration-response studies, separated by 1 hour, with either inhaled histamine or bradykinin. After recovery, a hypertonic saline challenge was performed. During the next phase, nine subjects underwent two concentration-response studies, separated by 1 hour, with hypertonic saline. After recovery, a bradykinin challenge was performed. RESULTS: On the histamine study day, the mean provocative volume of agonist required to produce 20% drop in forced expiratory volume in 1 second (PD20) hypertonic saline was 220.7 L (+/- 42.7 L) and this was not significantly different from that measured at baseline. On the bradykinin study day, the geometric mean provocative concentration of agonist required to produce a 20% drop in forced expiratory volume in 1 second (PC20) was 0.39 mg/ml (0.01 to 11.73 mg/ml) for the first test and significantly higher at 1.38 mg/ml (0.01 to > 16.0 mg/ml) for the second test (p = 0.006). The hypertonic saline PD20 increased significantly from a baseline of 159.2 L (+/- 27.3 L) to 377.6 (+/- 64.7 ) (p = 0.003). On the hypertonic saline study day, the mean PD20 was 152.8 L for the first test, and 337.7 L for the second test (p = 0.01). PC20 bradykinin increased significantly from a baseline of 0.57 to 2.56 mg/ml (p = 0.02). A significant correlation was found between loss of response to bradykinin and to hypertonic saline (rs, 0.63 and 0.76). CONCLUSION: Refractoriness produced by repeated exposure of the airways to bradykinin and hypertonic saline results in loss of responsiveness to hypertonic saline and bradykinin respectively, suggesting a shared mechanism for refractoriness produced by these stimuli.

Adolescent↗

PubMed1993

Relation of the hypertonic saline responsiveness of the airways to exercise induced asthma symptom severity and to histamine or methacholine reactivity.

BACKGROUND: Conflicting views exist over whether responsiveness of the airways to hypertonic saline relates to non-specific bronchial hyperresponsiveness measured by histamine or methacholine challenge. The bronchoconstrictor responses to exercise and hypertonic saline are reported to be closely related, but the relationship between the symptoms of exercise induced asthma and airway responsiveness to hypertonic saline is not known. METHODS: In 29 asthmatic patients with a history of exercise induced asthma, the response to an ultrasonically nebulised hypertonic saline (3.6% sodium chloride) aerosol, measured as the volume of hypertonic saline laden air required to produce a fall in forced expiratory volume in one second (FEV1) of > or = 20% (PD20), was compared with the concentration of histamine (PC20; group 1) and methacholine (PC20; group 2) producing a 20% fall in baseline FEV1 and exercise induced asthma symptom severity score (groups 1 and 2). The hypertonic responsiveness was determined in a dose-response manner to a maximum dose of 310 1 and the exercise induced asthma symptom severity was scored on a scale of 0-5. RESULTS: Of the 29 patients, 23 (79%) were responsive to the hypertonic saline, with PD20 values ranging from 9 to 310 1. A significant correlation was found between the PD20 hypertonic saline and the exercise induced asthma symptom score. There was no significant correlation between the PD20 response to hypertonic saline and the histamine PC20 or methacholine PC20. The exclusion of those subjects who failed to respond to hypertonic saline improved the relationship between hypertonic saline and methacholine PC20. No significant correlation was found between the exercise induced asthma symptom score and histamine PC20 or methacholine PC20. CONCLUSION: These findings suggest that hypertonic saline responsiveness bears a closer relationship to the severity of exercise induced asthma symptoms than to the non-specific bronchial hyperresponsiveness measured by histamine or methacholine reactivity.

Adult↗

PubMed1990

Effect of hypertonic saline on the corticotropin-releasing hormone and arginine vasopressin content of the rat pituitary neurointermediate lobe.

The changes in the levels of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) in the neurointermediate lobe of the pituitary (NIL) following hypertonic saline administration were examined in rats. The plasma osmotic pressure in rats receiving 2% NaCl for 8 days was greatly increased. Plasma AVP concentration in rats receiving 2% NaCl for 8 days were significantly higher than in control rats (566% of the control level). Plasma corticosterone was significantly higher in the saline-treated rats than in controls, whereas plasma ACTH was not significantly different. The pituitary ACTH concentration was much higher in the saline-treated rats than in controls. CRH in the NIL was increased significantly by saline treatment (419% of the control concentration), whereas the CRH in the paraventricular nucleus and median eminence of control and saline-treated rats did not differ significantly. The AVP in the NIL fell greatly in saline treated rats. The extract from both control and saline-treated rats showed a major peak for immunoreactive CRH, with a retention time identical to that of rat CRH. However, the peak was much higher in the extract from saline-treated rats. The immunoreactive AVP peak was greatly reduced in saline-treated rats. These results suggest that hypertonic saline administration increases the CRH in the NIL and causes AVP hypersecretion and/or hyperfunction of magnocellular-NIL CRH might be responsible for pituitary-adrenal stimulation in saline-treated rats.

Adrenal Cortex Hormones↗

PubMed1984

Small-volume resuscitation with hypertonic saline (2,400 mOsm/liter) during hemorrhagic shock.

We compared small-volume resuscitation using either normal saline or hypertonic saline (2400 mOsm/liter) during hemorrhagic hypotension. Six unanesthetized sheep were bled to 50 mm Hg mean arterial pressure and maintained for 2 h. During this shock period cardiac output decreased 40-50% of baseline, while total peripheral resistance increased 20-30%. Then the response to a bolus injection of either hypertonic saline or normal saline, randomly chosen, was studied for an additional 2 h. The volume injected was 145-175 ml, equal to 10% of total shed blood volume. After data collection all shed blood was returned. Several days later, the protocol was repeated on each sheep with the alternate solution. After hypertonic saline the mean arterial pressure increased 48 mm Hg to 83% of control; with normal saline, mean arterial pressure increased 26 mm Hg. Cardiac output recovered to 95% of control immediately after infusion of hypertonic saline, while no significant increase was observed with normal saline. Ten minutes after injection of hypertonic saline, plasma volume increased approximately 360 ml, but with normal saline no increase was observed. We conclude that small-volume injection of hypertonic saline can dramatically improve circulatory function during hemorrhagic shock, as evidenced by expansion of plasma volume, increased cardiac output, and reduced peripheral resistance.

Animals↗

PubMed2002

Salinity effects on growth, photosynthetic parameters, and nitrogenase activity in estuarine planktonic cyanobacteria.

Salinity has been suggested as being a controlling factor for blooms of N2-fixing cyanobacteria in estuaries. We tested the effect of salinity on the growth, N2 fixation, and photosynthetic activities of estuarine and freshwater isolates of heterocystous bloom-forming cyanobacteria. Anabaena aphanizomenoides and Anabaenopsis sp. were isolated from the Neuse River Estuary, North Carolina, and Cylindrospermopsis raciborskii from Lakes Dora and Griffin, central Florida. Salinity tolerance of these cyanobacteria was compared with that of two Nodularia strains from the Baltic Sea. We measured growth rates, N2 fixation (nitrogenase activity), and CO2 fixation at salinities between 0 and 20 g L(-1) NaCl. We also examined photosynthesis-irradiance relation-ships in response to salinity. Anabaenopsis maintained similar growth rates in the full range of salinities from 2 to 20 g L(-1) NaCl. Anabaena grew at up to 15 g L-', but the maximum salinity 20 g L(-1) NaCl was inhibitory. The upper limit for salinity tolerance of Cylindrospermopsis was 4 g L(-1) NaCl. Nodularia spp. maintained similar growth rates in the full range of salinities from 0 to 20 g L(-1) . Between 0 and 10 g L(-1), the growth rate of Nodularia spumigena was slower than that of the Neuse Estuary strains. In most strains, the sensitivity of nitrogenase activity and CO2 fixation to salinity appeared similar. Anabaenopsis, Anabaena, and the two Nodularia strains rapidly responded to NaCl by increasing their maximum photosynthetic rates (Pmn). Overall, both Neuse River Estuary and Baltic Sea strains showed an ability to acclimate to salt stress over short-(24 h) and long-term (several days to weeks) exposures. The study suggested that direct effect of salinity (as NaCl in these experiments) on cyanobacterial physiology does not alone explain the low frequency and magnitude of blooms of N2-fixing cyanobacteria in estuaries.

Adaptation, Physiological↗

PubMed1995

A randomized trial of extra-amniotic saline infusion versus laminaria for cervical ripening.

OBJECTIVE: To compare extra-amniotic saline infusion versus laminaria for cervical ripening and labor induction. METHODS: Patients of at least 34 weeks' gestation with a Bishop score of 3 or less were randomized to either laminaria ripening for 6 hours or more followed by oxytocin induction versus initiation of extra-amniotic saline infusion at the start of oxytocin induction. Indications for induction included 41 weeks' gestation or greater, hypertensive disease, diabetes, oligohydramnios, suspect fetal growth, and nonreassuring fetal testing. RESULTS: There were no significant differences in maternal age, race, parity, gestational age, or indications for induction between the two groups (extra-amniotic saline infusion group, n = 26, laminaria group, n = 26). After only 3 hours of oxytocin induction, patients in the extra-amniotic saline infusion group achieved an identical distribution of Bishop scores compared with the patients in the laminaria group after 6 hours or more of pre-induction ripening as well as 3 hours of oxytocin induction. There were no differences in rates of cesarean delivery (extra-amniotic saline infusion 35%, laminaria 35%), infectious complications, or neonatal outcomes between the two groups. The induction-to-delivery interval (+/- standard deviation) was significantly shortened with extra-amniotic saline infusion (extra-amniotic saline infusion 12.9 +/- 5.7 hours versus laminaria 16.9 +/- 7.1 hours, P = .03). In addition, fewer cesarean deliveries were performed for failed inductions (cervix less than 5 cm dilated) in the extra-amniotic saline infusion group (one of 26 versus six of 26, P = .049). CONCLUSION: Extra-amniotic saline infusion offers potential advantages over the use of laminaria. Extra-amniotic saline infusion saves a significant amount of time both by obviating the need for pre-induction cervical ripening and in shortening the induction-to-delivery interval. Also, fewer patients required cesarean delivery for failed induction of labor with extra-amniotic saline infusion.

Adult↗