Effect of osmolality on mucociliary transportability and rheology of cystic fibrosis and bronchiectasis sputum

OBJECTIVE: Water is the main constituent of mucus, and its concentration is likely to be important in all aspects of mucus function, including ciliary clearance. The objective of this study was to investigate the effect of water content and osmolality of the mucus on mucociliary transportability. METHODOLOGY: Rheology and ciliary transportability of 10 sputum samples that had been subjected to various manipulations were measured using a mucus-depleted bovine trachea model. RESULTS: It was shown that addition of sodium chloride 0.2 Osmoles/kg (0.585% weight for weight) increased the transportability by 41% (P < 0.01). Evaporation of the sputum to 50% of its original weight caused a 118% increase in transportability (P < 0.0006), but iso-osmolal removal of 50% of the liquid with filter cards led to a non-significant, 25% increase in transportability. Parallel plate viscoelasticity was approximately doubled in both the evaporated and liquid-depleted samples, but was not changed by the addition of 0.2 Osmoles/kg of sodium chloride. The correlation between the osmolality of sputum and ciliary transportability (r = 0.54, P= 0.005) was better than the correlations between the viscosity (r = 0.21, P= 0.27) or elasticity (r = 0.23, P= 0.23) and ciliary transportability. CONCLUSIONS: These results suggest that the osmolality of sputum exerts a greater influence on mucociliary clearance than its viscoelastic properties.     

Salt Reduction to Prevent Hypertension and Cardiovascular Disease: JACC State-of-the-Art Review

There is strong evidence for a causal relationship between salt intake and blood pressure. Randomized trials demonstrate that salt reduction lowers blood pressure in both individuals who are hypertensive and those who are normotensive, additively to antihypertensive treatments. Methodologically robust studies with accurate salt intake assessment have shown that a lower salt intake is associated with a reduced risk of cardiovascular disease, all-cause mortality, and other conditions, such as kidney disease, stomach cancer, and osteoporosis. Multiple complex and interconnected physiological mechanisms are implicated, including fluid homeostasis, hormonal and inflammatory mechanisms, as well as more novel pathways such as the immune response and the gut microbiome. High salt intake is a top dietary risk factor. Salt reduction programs are cost-effective and should be implemented or accelerated in all countries. This review provides an update on the evidence relating salt to health, with a particular focus on blood pressure and cardiovascular disease, as well as the potential mechanisms.     

Endoscopic therapy of early gastric cancer

Endoscopic therapy of early gastric cancer is applicable for differentiated-type mucosal carcinomas that have an extremely low potency of lymph-node metastasis. Among various kinds of endoscopic therapy, endoscopic mucosal resection is the most recommended procedure, because pathological evaluation of affected tissues is available using this method. Recently, endoscopic submucosal dissection, a novel method of endoscopic mucosal resection, has gained interest as a more reliable therapeutic procedure. In the present chapter several issues will be presented on endoscopic therapy for early gastric cancer, including endoscopic diagnosis of early gastric cancer, currently accepted indications of endoscopic therapy, and the possibility of extending the indication and techniques used for mucosal resection.     

Clinical and hormonal conditions associated with sodium retention in cirrhotic patients with ascites

Using multiple regression analysis, we have evaluated the clinical and hormonal conditions associated with impaired urinary sodium excretion in normoazotemic patients with cirrhosis and ascites. We retrospectively identified 13 patients with a urinary sodium excretion lower than 15 mmol/day and 13 patients with a sodium excretion higher than 15 mmol/day. Using univariate analysis, all the patients with poor sodium excretion had abnormally high levels of plasma renin activity, plasma aldosterone, and arginine vasopressin. In addition, they had a diastolic blood pressure lower than patients with high urinary sodium excretion, although otherwise were comparable as regards clinical and biochemical data. The consistency of the above associations was then tested by multiple-regression analysis in an attempt to control for potentially confounding factors and to identify only true, independent associations. After a discriminant stepwise procedure, we found that low diastolic blood pressure (P<0.01) and high plasma aldosterone levels (P<0.05) were the only two conditions independently associated with abnormally low urinary sodium excretion. These findings are consistent with the view that sodium retention in decompensated cirrhosis results from a concomitant severe contraction in the effective blood volume and an increased production and/or retention of aldosterone. The concordance between our results and several pathophysiological findings supports the validity of this statistical approach to confirm physiological and/or clinical predictions.Portions of this work were presented at the Annual Meeting of the Italian Association for the Study of the Liver, Rome, June 1984.     

Differences in composition of sweat induced by thermal exposure and by running exercise

To determine the differences in sweat composition between sweat induced by thermal stress alone and that induced by physical exercise, seven young healthy men first sat in a hot room and then performed running exercise. A 20-minute stay in a climate chamber at 40 degrees C resulted in a 5% reduction in body weight. The same body weight loss was induced by running exercise. Both sodium and chloride concentrations were much lower in the sweat induced by thermal exposure than that induced by the running exercise (p less than 0.01), while urea nitrogen and creatinine concentrations were significantly higher after thermal exposure than after the running exercise (p less than 0.01). Potassium concentrations did not differ significantly with either procedure. These findings suggest that sweat composition varies with the kind of induction and that more salt seems to be lost through exercise-induced sweating than by just sitting in a hot environment.     

Dextran Sulfate Sodium-Induced Colitis in Immunodeficient Rats

To examine the morphology of colitis and study the role of the immune system in colitis, we compared colitis in immunocompetent Wistar-Kyoto rats with that in spontaneously hypertensive rats, known to have T-cell dysfunction. Rats were treated with 3% dextran sulfate in drinking water for periods ranging from 3 to 60 days. Diarrhea developed earlier and was associated with a more severe weight loss in Wistar-Kyoto rats than spontaneously hypertensive rats. The morphologic findings (flattening of the gland epithelium, gland dropout and ulceration) in spontaneously hypertensive rats were milder than in Wistar-Kyoto rats. Only spontaneously hypertensive rats survived 60 days of treatment; the findings included ulceration, crypt distortion, and inflammatory pseudopolyp formation. Immunostaining for B-cell, T-cell, and macrophage markers showed no difference in the distribution of these cells in the mucosa of Wistar-Kyoto rats and spontaneously hypertensive rats. Spontaneously hypertensive rats with T-cell dysfunction develop dextran sulfate sodium-induced colitis.     

On the biogeography of salt limitation: A study of ant communities

Sodium is an essential nutrient whose deposition in rainfall decreases with distance inland. The herbivores and microbial decomposers that feed on sodium-poor vegetation should be particularly constrained along gradients of decreasing sodium. We studied the use of sucrose and NaCl baits in 17 New World ant communities located 4–2757 km inland. Sodium use was higher in genera and subfamilies characterized as omnivores/herbivores compared with those classified as carnivores and was lower in communities embedded in forest litter than in those embedded in abundant vegetation. Sodium use was increased in ant communities further inland, as was preference for the baits with the highest sodium concentration. Sucrose use, a measure of ant activity, peaked in communities 10–100 km inland. We suggest that the geography of ant activity is shaped by sodium toxicity near the shore and by sodium deficit farther inland. Given the importance of ants in terrestrial ecosystems, changing patterns of rainfall with global change may ramify through inland food webs.     

Beta-adrenergic stimulation of pig myocytes with decreased cytosolic free magnesium prolongs the action potential and enhances triggered activity

INTRODUCTION: Heart failure results in chronic beta-adrenergic stimulation, repolarization lability, and arrhythmias associated with early afterdepolarizations (EADs) and delayed afterdepolarizations (DADs). Having described a significant reduction in intracellular free magnesium ([Mg2+]i) in experimental heart failure, we asked whether a reduction in [Mg2+]i would delay repolarization or facilitate EADs and/or DADs. METHODS AND RESULTS: Left ventricular myocytes were isolated from Yorkshire swine. Cytosolic free [Mg2+] was set at 0.12 mM (LoMg) or 1.2 mM (HiMg) through pipette dialysis. Action potentials (AP), Ca current (I(Ca)), and sodium/calcium exchange current (I(NCX)) were measured in the presence or absence of isoproterenol (2 microM) at 37 degrees C. Under basal conditions (0.1-Hz stimulation, 2 mM external [Ca2+]), reducing [Mg2+]i had no effect on AP duration and I(Ca) but did significantly enhance I(NCX). In contrast, during superfusion with isoproterenol, reduced [Mg2+]i caused a significant increase in AP duration at both 50% and 90% repolarization (APD50 and APD90) compared with HiMg (P < 0.05). LoMg cells manifested a high incidence of triggered activities, including spontaneous AP, EADs, and DADs (83.3% in LoMg, n = 12 vs 38.3% in HiMg, n = 13; P < 0.05). I(Ca) and I(NCX) were significantly increased in LoMg cells compared with HiMg cells (P < 0.05). CONCLUSION: Decreased cytosolic free magnesium prolongs AP duration and increases the incidence of triggered activity during beta-adrenergic stimulation. These effects may be due to increased I(Ca) and I(NCX) in the presence of reduced intracellular [Mg2+]. A magnesium-dependent increase in triggered activity coupled with delayed repolarization during beta-adrenergic stimulation could contribute to the arrhythmogenic substrate in heart failure.     

阿仑膦酸钠与阿法骨化醇治疗老年性骨质疏松症的疗效比较

目的比较阿仑膦酸钠片、阿法骨化醇胶囊治疗老年性骨质疏松症的临床疗效及安全性。方法将56例老年性骨质疏松症患者,采取随机法分成2组。观察组给予口服阿仑膦酸钠片70 mg,每周1次;对照组给予口服阿法骨化醇胶囊0.5μg,每日1次;同时2组患者每天均服用钙剂600 mg,连续治疗6个月。测定治疗前后骨密度(BMD)、生化指标,采取VAS法评价治疗前后疼痛改善情况等。结果治疗后观察组的L2、L3、L4、股骨颈的骨密度值分别增加了3.61%、4.76%、3.66%和5.06%;观察组的骨密度值分别增加了3.57%、4.71%、3.61%和5.0%,2组间差异无统计学意义(p>0.05)。治疗后观察组改善疼痛症状优于对照组(p<0.05)。结论两种药物治疗老年性骨质疏松症具有良好的临床疗效,能显著增加患者骨密度,缓解疼痛程度;但阿仑膦酸钠片服药方便,患者顺从性较好,较适宜在临床推广应用。