Red Blood Cell Sodium Research Articles

Comparison of the effect between traditional conservation and nasointestinal tube placement in adhesive small bowel obstruction: A matched case-control study

Adhesive small bowel obstruction (ASBO) causes a major burden in emergency medicine. Owing to in situ decompression, nasointestinal tube (NIT) placement has been increasingly used in clinical practice compared with traditional conservation (TC); however, the indications remain controversial. This study was designed to explore the indications for each treatment in ASBOs and then suggest the optimal strategy.After propensity score matching, 128 pairs were included (the NIT and TC groups). The occurrence of severe adverse events (SAEs), peri-treatment clinical parameters, and radiological features were compared between the successful and failed treatment groups.According to different stages of the entire treatment, the independent risk factors for adverse effects for ASBO were analysed in phase I and phase II. In phase I, normal red blood cells (RBC) levels (p = 0.011) and a balanced sodium ion level (p = 0.016) positively affected the outcomes of TC treatment. In phase II, for the TC group, the successful treatment rate reached 79.5% for patients with ASBOs whose normal RBC levels (p = 0.006) or decreasing white blood cells (WBC) levels (p = 0.014) after treatment. For the NIT group, the treatment success rate was 68.1% for patients whose electrolyte imbalance could be reversed or whose neutrophil count/lymphocyte ratio (NLR) levels was lower than 4.3 (p = 0.018).TC treatment is highly recommended for patients with normal RBC counts and sodium levels pretreatment. After dynamic monitoring of the treatment process, for both the TC and NIT groups, once ASBOs had elevated inflammatory biomarkers or irreversible electrolyte disturbances, surgical interference was preferred.

Cryopreservation of red blood cells: Effect on rheologic properties and associated metabolic and nitric oxide related parameters

AimHigh glycerol cryopreservation of red blood cells (RBCs) reduces metabolic processes at ultralow temperatures but less is known regarding the effect of cryopreservation on RBC nitric oxide (NO) metabolism, haemorheological properties, structural behaviour and membrane fragility. MethodsBlood from ten healthy participants was sampled, glycerolized and stored at −80 °C (SB). Aliquots were thawed and further processed after 4, 8 and 12 weeks, respectively. At these time points, fresh blood (FB) was additionally sampled from each participant. FB/SB mixtures were prepared corresponding to transfusion of 1–3 blood bags. Additionally, mixtures were exposed to shear stress similar to that found in the circulation and deformability was measured to estimate possible behaviour of cryopreserved RBC in vivo. ResultsAgeing of RBC was reduced during cryopreservation. Markers for RBC metabolism (ATP, 2,3-DPG) were not altered but RBC sodium levels increased and potassium and calcium decreased, respectively. Mean cellular volume was higher and accordingly, mean cellular haemoglobin concentration was lower in SB. Deformability was altered during storage with less shear stress necessary to deform RBCs. Changes were also detectable in blood mixtures. Deformability remained unaltered in shear stress settings in FB and SB. RBC viscosity was reduced in SB. RBC-NOS content and phosphorylation sites as well as nitrite and RxNO levels seem not to be affected by the intervention. ConclusionCryopreservation maintains RBC metabolic function in vitro, but structure and function of cryopreserved RBC seems to be altered. Impact of these alterations in vivo seems to be less but needs further investigation.

Salt Sensitivity Determined From Capillary Blood

Background/Aims: A significant rise of blood pressure in response to a given salt load is a weak indication of high salt sensitivity, supposed to foster the development of arterial hypertension and related diseases in later life. In search of an alternative method we recently developed the salt blood test (SBT), a new concept for quantifying salt sensitivity (SS). Based on this concept, namely that red blood cells (RBC) report on salt sensitivity, the SBT-mini was developed. Methods: The SBT-mini utilizes a droplet of capillary blood mixed with a ‘smart' Na⁺ cocktail. Red blood cells (RBC) of this mixture are allowed to sediment by gravity in a glass tube. SS is quantified by measuring RBC sedimentation rate. 90 healthy volunteers (39 males, 51 females; mean age: 23±0.5 years) were evaluated and ‘standard values' for males and females were derived. Results: Sodium buffer capacity of female blood is about 20 % smaller as compared to male blood due to the lower hematocrit of females. SS of an individual is related to the mean standard value (set to 100 %) of the respective male/female cohort. High SS (> 120 %) has been found in 31 % of males and 28 % of females. Conclusions: SS can be estimated derived from the individual RBC sodium buffer capacity as measured by the SBT-mini. About one third of a healthy test cohort exhibits a high sensitivity to salt. Reduction of sodium consumption to at least two grams per day (equals five grams of NaCl per day as suggested by the WHO) is recommended, particularly for individuals with high salt sensitivity.

Evaluation of physiological and biochemical responses in different seasons in Surti buffaloes.

Aim:This study was conducted to evaluate the impact of hot dry, hot humid and comfortable season on physiological, hematological, biochemical, and oxidative stress parameters in Surti buffaloes.Materials and Methods:Ten lactating Surti buffaloes of similar physiological status were selected. Based on the temperature-humidity index (THI), their natural exposure to the environment was categorized as hot dry (THI1), hot humid (THI2) and moderate winter/comfort season (THI3). Blood/serum samples were collected and analyzed for physiological, hematological, biochemical, and oxidative stress parameters. The results were analyzed using standard statistical methods.Results:With increase in THI, significant rise in physiological parameters such as respiration rate (RR), hematological parameters such as red blood cell (RBC), hematocrit, hemoglobin (Hb) and mean cell Hb concentration (MCHC), biochemical parameters such as alanine aminotransferase (ALT), Na, K, creatinine, blood urea nitrogen, Mn, Cu and Zn, hormones such as cortisol and oxidative stress parameters such as glutathione peroxidase (GPx), superoxide dismutase (SOD), lipid peroxide (LPO) and total antioxidant status (TAS) and significant decline in glucose, cholesterol and triiodothyronine (T3) was observed.Conclusion:It was concluded that THI is a sensitive indicator of heat stress and is impacted by ambient temperature more than the relative humidity in buffaloes. Higher THI is associated with significantly increased RR, total RBC count, Hb, hematocrit, MCHC, ALT, urea, sodium, creatinine, triiodothyronine, SOD, GPx, LPO and TAS and with significant decrease in glucose, cholesterol and triiodothyronine (T3).

Red blood cell sodium transport in patients with cirrhosis.

Patients with advanced cirrhosis have abnormal sodium homoeostasis. The study was undertaken to quantify the sodium transport across the plasma membrane of red blood cells (RBC) in patients with cirrhosis. RBC efflux and influx of sodium were studied in vitro with tracer (22) Na(+) according to linear kinetics in 24 patients with cirrhosis and 14 healthy controls. The sodium efflux was modified by ouabain (O), furosemide (F) and a combination of O and F (O+F). RBC sodium was significantly decreased (4·6 versus control 6·3mmoll(-1) , P<0·001) and directly related to serum sodium (r=0·57, P<0·05). The RBC fractional sodium efflux was higher in patients with cirrhosis (+46%, P<0·01) compared to controls. Inhibition in both high (145mmoll(-1) )- and low (120mmoll(-1) )-sodium buffers showed that the F-insensitive sodium efflux was twice as high in cirrhosis as in controls (P=0·03-0·007), especially the O-sensitive, F-insensitive efflux was increased (+ 225%, P=0·01-0·006). Fractional F-sensitive transport was normal in cirrhosis. RBC sodium influx was largely normal in cirrhosis. In conclusion, RBC sodium content is reduced in patients with cirrhosis with a direct relation to serum sodium. Increased RBC sodium efflux is especially related to ouabain-sensitive, furosemide-insensitive transport and thus most likely due to upregulated activity of the sodium-potassium pump. The study gives no evidence to an altered intracellular/extracellular sodium ratio or to a reduced fractional furosemide-sensitive sodium transport in cirrhosis.

Vascular endothelium: a vulnerable transit zone for merciless sodium

In humans, when plasma sodium concentration rises slightly beyond 140 mM, vascular endothelium sharply stiffens and nitric oxide release declines. In search of a vascular sodium sensor, the endothelial glycocalyx was identified as being a negatively charged biopolymer capable of selectively buffering sodium ions. Sodium excess damages the glycocalyx and renders vascular endothelium increasingly permeable for sodium. In the long term, sodium accumulates in the interstitium and gradually damages the organism. It was discovered that circulating red blood cells (RBC) 'report' surface properties of the vascular endothelium. To some extent, the RBC glycocalyx mirrors the endothelial glycocalyx. A poor (charge-deprived) endothelial glycocalyx causes a poor RBC glycocalyx and vice versa. This observation led to the assumption that the current state of an individual's vascular endothelium in terms of electrical surface charges and sodium-buffering capabilities could be read simply from a blood sample. Recently, a so-called salt blood test was introduced that quantifies the RBC sodium buffer capacity and thus characterizes the endothelial function. The arguments are outlined in this article spanning a bridge from cellular nano-mechanics to clinical application.

Clinical evaluation of lipids, lipoproteins and red blood cells sodium and potassium in patients with different grades of hypertension

Objectives To show that lipid and lipoprotein levels and cell sodium and potassium content and transport could change depending on the degree of hypertension. Design and methods Forty-three hypertensive patients and 20 healthy subjects were recruited at the Cardiology and Biochemistry Departments of Tlemcen University Hospital Centre (Northwest of Algeria). Results Levels of CHOL, TG, PL, HDL-TG, LDLc, LDL-TG, LDL-PL, HDL2-TG and HDL3-TG were significantly higher in hypertensive patients than those in controls. HDL-PL levels were significantly lower in patients compared with controls and decreased according to the grade of hypertension. HDL2c, HDL2-PL and HDL3-TG and cell content and fluxes of sodium and potassium change gradually with higher grades of hypertension. Conclusions Hypertensive patients with circulating lipid alterations are associated to ion cell content and transport abnormalities, which were worsened progressively with higher grade of hypertension.

Two-dimensional, sex-specific autosomal linkage scan of the number of sodium pump sites

The sodium pump consists of the membrane-bound enzyme sodium/potassium-ATPase, which exchanges internal sodium ions for external potassium ions. Obesity, hypertension, and diabetes associate with the activity of the sodium pump, motivating gene discovery for sodium pump number. Variance components linkage analysis was applied to the number of red blood cell sodium pump sites measured by ouabain-binding assays on 1375 members of 46 Utah pedigrees. Both one-dimensional (1D) and two-dimensional (2D) autosome-wide linkage analyses of pump number were performed on the combined sample as well as separately on the male and female subsets. Two significant 1D linkages were identified: on chromosome 1p13 in the combined sample [1D logarithm of odds (LOD) score = 3.76] and on chromosome 17p21 in the female subset (1D LOD score = 3.24). In addition, two significant 2D linkages were identified in the female subset: on chromosome 10q22 interacting with chromosome 18q11 (2D LOD score = 7.18) and on chromosome 13q21 interacting with chromosome 4q31 (2D LOD score = 6.05). Single-nucleotide polymorphism rs17376826 in neuropeptide Y receptor Y2, an obesity-associated gene and a candidate in the chromosome 4q31 linkage region, is associated with pump number (P = 0.046 in the combined sample and P = 0.042 in the female subset). Pump number is influenced by multiple genes, possibly including neuropeptide Y receptor Y2.

Effects of hormone replacement therapy with vitamin C and E supplementation on plasma thyroid hormone levels in postmenopausal women with Type 2 diabetes

Recent studies have shown that hormone replacement therapy (HRT) can exert regulatory affects on lipid and glucose homeostasis. It has been demonstrated that hyperglycemia also involving the formation of lipid peroxides, exert several biological effects that may contribute to the onset and progression of thyroid and kidney abnormalities of postmenopausal women Type 2 diabetes. Therefore, the aim of our study was to evaluate the effect of HRT, vitamin C and E (VCE) treatments on some plasma biochemical and hematological parameters and plasma thyroid hormone levels in postmenopausal women with or without diabetes. Oral HRT and VCE supplementation were compared with no HRT treatment in 40 non-diabetic postmenopausal women and 40 postmenopausal women with Type 2 diabetes mellitus, in a 6-week randomized prospective study. In the 20 women with diabetes who received oral HRT and the 20 women with diabetes who received HRT plus VCE, there was a significant fall in urea, uric acid, creatinine, total bilirubin, conjugated bilirubin, AST, ALT, LDH values. There was no significant change in red blood cell counts, total protein, albumin, sodium, potassium, hematocrit, hemoglobin and free thyrotoxine and triiodothyronine values in postmenopausal women with diabetes or treated with oral HRT and VCE. In conclusion, daily VCE and HRT administrations seem to produce significant improvement on biochemical parameters in the blood of postmenopausal women with Type 2 diabetes. The HRT and VCE supplementations may strengthen the antioxidant defense system and they may play a role in preventing kidney and liver diseases of postmenopausal women with Type 2 diabetes.

Magnesium status and dietary intake of mid-old people in a rural area of China

To evaluate the status and dietary intake of magnesium in mid-old people in a rural area of China, a total of 324 mid-old people (111 males and 213 females) aged 55-70 were randomly selected. All the subjects were divided into four groups: a normal group (N), a hypertension group (H), an impaired fasting glucose group (IFG) and a diabetic group (D). Magnesium, sodium, potassium, calcium, iron, zinc, and copper concentrations in red blood cells (RBC) were measured by emission spectroscopy (ICP-OES), and dietary intakes were surveyed by 24-hr recall questionnaires. The data were analyzed between groups and also between genders. The average body weight and BMI were 59.4 kg and 22.1 in subjects with IFG, and 62.4 kg and 23.5 in the diabetics, which were higher than those of the normal group (p < 0.05 and p < 0.01). The average magnesium concentration in RBC was significantly lower in the hypertension group than in the normal group (2.0 mmol/L vs. 2.2 mmol/L, p < 0.05). Groups H, IFG and D took less magnesium than group N (315.9 mg/d, 331.6 mg/d and 323.3 mg/d vs. 371.54 mg/d, p < 0.05). Women took less magnesium than men (326.2 mg/d vs. 373.7 mg/d, p < 0.05). There were no significant differences in other mineral concentrations in RBC and dietary intakes. Results of this study show that magnesium concentration in RBC is lower in mid-old people suffering hypertension as compared to healthy subjects. Dietary intakes of magnesium are lower in mid-old people suffering hypertension, IFG and diabetes as compared to healthy subjects. This indicates that an increase in the magnesium supply would be beneficial to mid-old people.

Cations Content And Membrane Properties Of Human Sickle Blood Incubated With Hydroxyurea, Tellurite And Thiocyanate

The effect of hydroxyurea, sodium thiocyanate and potassium tellurite on cations content and membrane properties of sickle erythrocyte was investigated in this study. Human sickle blood was incubated with the drugs in vitro at their optimum sickling inhibitory concentration. Mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC), cations (Na+, K+ and Ca2+) contents and viscosity were measured. Tellurite and thiocyanate significantly increased (P&#61500;0.05) MCV, reduced MCHC and blood viscosity and also significantly inhibited (P&#61500;0.05) calcium accumulation by sickle red blood cell. In addition, the two drugs increased red blood cell sodium gain and inhibited potassium loss significantly. Incubation of the drugs with sickle erythrocyte ghost membrane indicated that tellurite and thiocyanate significantly inhibited (P&#61500;0.05) Na+-K+-ATPase (EC 3.6.3.9) and Ca2+-Mg2+-ATPase (EC 3.6.3.8) activities. Blood incubated with hydroxyurea also significantly inhibited (P&#61500;0.05) calcium ion accumulation but had no effect on all other measured parameters. This result suggests that thiocyanate and tellurite have positive modification effect on sickle erythrocyte membrane and cation transport thereby causing rehydration and improvement in red blood cell deformability. Keywords: Cations content, Erythrocyte Membrane, Hydroxyurea, Sodium thiocyanate, Potassium tellurite Egyptian Journal of Biochemistry and Molecular Biology Vol. 26 (1) 2008 pp. 117-125

More on the sodium saga.

The relationship between sodium (salt) intake and blood pressure has been convincingly established by epidemiological, observational, interventional, physiological, and some genetic evidence for some time. Yet the interaction remains the subject of passionate and heated debate. Even among those who are convinced of the salt–blood pressure interaction, some advocate a population-wide attempt to reduce dietary salt intake, arguing on the basis of epidemiological and interventional evidence, and others who suggest that such interventions should be targeted toward those most likely to benefit: the “salt-sensitive” subpopulation. Studies have characterized such subgroups on the basis of higher blood pressure, increased age or African-American ethnicity.1 The issue is rendered even more compelling by the findings that salt sensitivity can be identified among “normotensive” subjects (ie, those with blood pressure <140/90) as well as those with hypertension1 and the designation of those with blood pressure levels between 120 and 139 mm Hg systolic and 80 and 89 diastolic as prehypertensive2 and at increased risk for development of fixed hypertension and for cardiovascular events compared with those with lower blood pressure.3 Observational data have provided a starting point for the quantitative considerations of dietary salt intake. The most recent (1999–2000) NHANES survey provides an estimated dietary sodium intake based on food records, excluding discretionary sodium, of 135 to 204 mmol per day for men and 100 to 135 mmol per day for women in the United States.4 Questionnaires are acknowledged to underestimate actual intake, and urinary sodium excretion has been shown to provide a more accurate index of total sodium intake because it represents ≈93% of intake at steady-state conditions.5 A recent British survey reported that urinary sodium excretion averaged 187 mmol per day for men and 139 mmol per day for women.5 This was very similar to …

A stomatin and a degenerin interact in lipid rafts of the nervous system of Caenorhabditis elegans.

In Caenorhabditis elegans, the gene unc-1 controls anesthetic sensitivity and normal locomotion. The protein UNC-1 is a close homolog of the mammalian protein stomatin and is expressed primarily in the nervous system. Genetic studies in C. elegans have shown that the UNC-1 protein interacts with a sodium channel subunit, UNC-8. In humans, absence of stomatin is associated with abnormal sodium and potassium levels in red blood cells. Stomatin also has been postulated to participate in the formation of lipid rafts, which are membrane microdomains associated with protein complexes, cholesterol, and sphingolipids. In this study, we isolated a low-density, detergent-resistant fraction from cell membranes of C. elegans. This fraction contains cholesterol, sphingolipids, and protein consistent with their identification as lipid rafts. We then probed Western blots of protein from the rafts and found that the UNC-1 protein is almost totally restricted to this fraction. The UNC-8 protein is also found in rafts and coimmunoprecipitates UNC-1. A second stomatin-like protein, UNC-24, also affects anesthetic sensitivity, is found in lipid rafts, and regulates UNC-1 distribution. Mutations in the unc-24 gene alter the distribution of UNC-1 in lipid rafts. Each of these mutations alters anesthetic sensitivity in C. elegans. Because lipid rafts contain many of the putative targets of volatile anesthetics, they may represent a novel class of targets for volatile anesthetics.

Mechanism underlying the strong positive inotropic effects of LND-623: specific inhibition of Na, K-ATPase isoforms and exclusion of cellular sites of contractile control.

LND-623 is a new aminosteroid analog of ouabain, with a greater separation between efficacy and toxicity than ouabain. To determine its mechanism of action, we studied its biochemical and physiological effects on human red blood cell sodium transports on different cellular structures regarded as sites of contractile control, and we compared its relative efficacy to ouabain in rat heart preparations and membrane-bound Na, K-ATPase isoenzymes. The response to ouabain was evaluated in Langendorff-perfused hearts and on purified membrane-bound Na, K-ATPase. LND-623 is 6.8-fold more efficient than ouabain in inhibiting the human Na+ pump (IC50 = 0.098 +/- 0.001 microM vs. 0.67 +/- 0.02 microM); (P < 0.0001). LND-623 had no effect on the following cellular functions: Na-Ca exchange, Na-K cotransport, Ca-ATPase, slow calcium channels, adenylate cyclase system, phosphodiesterase, and calcium sensitivity of the contractile protein system. The dose-response curve for the positive inotropic and inhibitory effects on rat cardiac isoenzymes produced by LND-623 were clearly biphasic. The amplitude of the maximum inotropic effect, without any toxic effect, was up to three-fold higher with LND-623 than with the same maximum dose of ouabain used. The strong positive inotropic effect of LND-623 in rats could be related to a specific inhibition of the two rat cardiac isoforms of the Na, K-ATPase.

Sodium lithium countertransport and blood pressure. Longitudinal findings.

A significant and positive association between red blood cell sodium lithium countertransport (Na-Li CT) and blood pressure has been found in numerous studies. However, the majority of the studies presented to date are cross-sectional in nature and limited information exists on the longitudinal association between Na-Li CT and blood pressure. The present study analyzes the longitudinal association between Na-Li CT and blood pressure in 124 men participants in the Olivetti Heart Study and normotensives at the baseline examination. The Na-Li CT measured at the 12 year follow-up examination was analyzed in regard to the blood pressure changes over time during the 12 year follow-up. Na-Li CT (measured at follow-up examination) was positively related to changes over time in systolic pressure (r = 0.16) and diastolic pressure (r = 0.07) and changes in body mass index (r = 0.18). When blood pressure changes over time were analyzed by tertiles of Na-Li CT, the highest tertile group exhibited on the average significantly higher increases in systolic blood pressure compared with participants of the lowest tertile of the Na-Li CT distribution. This difference remained statistically significant after adjusting for the changes in weight observed during the 12 years follow-up. These findings indicate that the Na-Li CT distribution is related to blood pressure changes over time. However, the usefulness of Na-Li CT as a predictor of incidence of hypertension remains to be established.

A23Na Multiple-Quantum-Filtered NMR Study of the Effect of the Cytoskeleton Conformation on the Anisotropic Motion of Sodium Ions in Red Blood Cells

Recently, it has been shown that23Na double-quantum-filtered NMR spectroscopy can be used to detect anisotropic motion of bound sodium ions in biological systems. The technique is based on the formation of the second-rank tensor when the quadrupolar interaction is not averaged to zero. Using this method, anisotropic motion of bound sodium in human and dog red blood cells was detected, and the effect was shown to depend on the integrity of the membrane cytoskeleton. In the present study, multiple-quantum-filtered techniques were applied in combination with a quadrupolar echo to measure the transverse-relaxation times,T2fandT2s. Line fitting was performed to obtain the values of the residual quadrupolar interaction, which was measured for sodium in a variety of mammalian erythrocytes of different size, shape, rheological properties, and sodium concentrations. Human unsealed white ghosts were used to study sodium bound at the anisotropic sites on the inner side of the RBC membrane. Modulations of the conformation of the cytoskeleton by the variation of either the ionic strength or pH of the suspending medium caused drastic changes in both the residual quadrupolar interaction andT2fdue to changes in the fraction of bound sodium ions as well as changes in the structure of the binding sites. By combining the two spectroscopic parameters, structural change can be followed. The changes in the structure of the sodium anisotropic binding sites deduced by this method were found to correlate with known conformational changes of the membrane cytoskeleton. Variations of the medium pH affected both the fraction of bound sodium ions and the structure of the anisotropic binding sites. Sodium and potassium were shown to bind to the anisotropic binding sites with the same affinity.

Increased Cation Permeability in Mutant Mouse Red Blood Cells With Defective Membrane Skeletons

Cellular cation homeostasis in mouse erythrocytes with defective membrane skeletons was examined in three mouse mutants, hemolytic anemia (sphha/sphha), spherocytosis (sph/sph), and normoblastosis (nb/nb), and compared with reticulocytes produced by repetitive bleeding of congenic normal mice. To assess reticulocyte maturity, nucleic acid and transferrin receptor contents were measured by fluorescence flow cytometry; mutant cells were somewhat more mature than normal reticulocytes by these criteria. Red blood cell (RBC) sodium contents (Nac+) in homozygous sphha/sphha, sph/sph, and nb/nb animals were 30.1 +/- 0.9, 28.9 +/- 0.3, and 26.9 +/- 1.5 mmol/L cell, respectively, whereas cellular potassium (Kc+) was 102 +/- 2.6, 101 +/- 7.8, and 97.4 +/- 3.0. Nac+ and Kc+ in normal reticulocyte preparations were 11.3 +/- 0.7 and 123 +/- 10, respectively. Net Na+ and K+ fluxes in the presence of ouabain were markedly increased in mutant RBCs. Sodium uptake was 14.8 +/- 1.6, 15.4 +/- 3.3, and 14.7 +/- 3.1 mmol/L cell/h in sphha/sphha, sph/sph, and nb/nb mutants, respectively, whereas K+ loss was 17.0 +/- 4.0, 15.0 +/- 3.8, and 14.1 +/- 2.6. Normal mouse reticulocytes gained Na+ at a rate of 3.9 +/- 1.0 mmol/L cell/h and lost K+ at 6.0 +/- 2.1, rates indistinguishable from those in mature mouse RBCs. Potassium loss from sphha/sphha and nb/nb cells was not dependent on the presence of a Na+ gradient, and net cation movements were insensitive to bumetanide (sphha/sphha and nb/nb RBCs) and to chloride replacement with sulfamate (nb/nb cells). We conclude that mutant mouse RBCs with dysfunctional membrane skeletons have increased passive permeability to monovalent cations. These findings support a role of the membrane skeleton in the maintenance of the membrane permeability barrier and suggest that the abnormal permeability associated with human hereditary spherocytosis and elliptocytosis may be a consequence of the membrane skeleton defects reported in these disorders.

Calcium Supplementation Attenuates an Enhanced Platelet Function in Salt-Loaded Mildly Hypertensive Patients

We designed this study to evaluate the effect of low versus high calcium intake on platelet function in salt-loaded patients with mild hypertension. After a 7-day period of dietary salt restriction, 19 patients were placed on a high salt (300 mmol/d), low calcium (6.25 mmol/d) diet for 7 days; 10 of these patients were given 54 mmol/d of supplementary calcium, and 9 patients were given placebo. At the end of the low and high salt regimens, we evaluated changes in blood pressure, platelet aggregation, and the platelet release reaction measured as plasma beta-thromboglobulin and platelet factor 4 levels. With high salt intake, significant increases in mean blood pressure (P < .02), red blood cell sodium (P < .01), and platelet aggregation induced by 3 mumol/L ADP (P < .01) and by 3.0 mg/L epinephrine (P < .05) were observed in the placebo-treated patients but not in the calcium-supplemented ones. Compared with the placebo-treated patients, calcium-supplemented patients had a smaller weight gain (P < .05) but excreted more sodium and calcium (P < .01) at the end of the high salt regimen. Calcium supplementation resulted in decreases in beta-thromboglobulin (P < .05), platelet factor 4 (P < .01), and plasma and urinary excretions of norepinephrine (P < .02) during the high salt, low calcium regimen. The decrease in plasma norepinephrine correlated positively with the decreases in beta-thromboglobulin (r = .72, P < .02) and platelet factor 4 (r = .85, P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Red blood cell sodium and potassium concentration and blood pressure: The Gubbio Population Study

The relations of red blood cell sodium (RBC Na) and potassium (RBC K) concentrations to blood pressure and prevalence of hypertension were assessed for 1805 men and women, aged 25 to 74 years, who participated in the baseline examination of the Gubbio Population Study in north central Italy. In men, in univariate analyses, RBC Na concentration was not significantly related to systolic or diastolic blood pressure, while RBC K concentration was significantly and inversely related to blood pressure. In women RBC Na values correlated significantly and directly with systolic and diastolic pressure, but RBC K concentration was not significantly related to blood pressure. Results of the multivariate analyses indicated in men a significant independent and inverse relationship of RBC K concentration with hypertension and blood pressure, and in women a significant positive association of RBC Na concentration with hypertension. RBC Na did not relate independently to either systolic or diastolic blood pressure in men or women. Age-specific analyses suggested that the relationships between RBC K level and blood pressure in men and the relationship between RBC Na level and hypertension in women were stronger in older (age 55 to 74 years) compared to younger participants (25 to 54 years). These findings indicate that the associations of RBC Na and K concentrations and hypertension may be sex and age specific. The nature of these gender- and age-specific associations remains to be clarified. Prospective data are also needed for further clarification of the relation of intracellular Na metabolism to the etiology of hypertension.

Red blood cell sodium content in NID diabetic patients with hemorheological abnormalities

Red blood cell sodium content in NID diabetic patients with hemorheological abnormalities