Sodium Concentrations In Samples Research Articles

Single-ion activity: Optical sensing vs. electrochemical sensing

An approach is proposed aimed at sensing single-ion activities with ionophore-based bulk optodes. The approach relies on the stabilization of the Galvani potential difference at the optode/sample interface, e.g. by use of tetrabutylammonium tetrabutylborate (Q+B−): a moderately lipophilic electrolyte used in solid reference electrodes. The pH/Na optode is successfully utilized as a model system. Optodes modified with Q+B− show practically the same response to pH at distinctively different concentrations of sodium in samples.

Duodenogastric reflux: a cause of gastric mucosal hyperaemia and symptoms after operations for peptic ulceration.

This study has investigated the possible association between duodenogastric reflux, gastritis, and symptoms in 35 patients with or without dyspepsia one to 15 years after gastric surgery. Five patients were excluded because of biliary disease, hiatus hernia, or recurrent ulceration. The remaining 30 were assessed by a symptomatic score, measurement, of bilirubin and sodium concentrations in samples of fasting gastric juice, endoscopy, gastric biopsy, and the presence of radiological reflux. In 15 patients with a symptom score of less than the median, gastric bilirubin levels were less than 1 mg/100 ml in 80%; severe endoscopic changes were seen in only one patient and reflux was not observed. In contrast, in patients with a symptom score in excess of the median fluoroscopic and biochemical reflux was seen in 69 and 80% respectively and severe mucosal hyperaemia in half. There was a significant correlation between symptoms, gastric hyperaemia, and duodenal reflus ( P smaller than 0-02).

Excretion of sodium and potassium in cat submandibular saliva.

AbstractThe concentrations of ions in the saliva vary with the secretory rate. Different results concerning sodium concentration in relation to flow rate have been found by different investigators. In the present work secretion was elicited by chorda stimulation and the concentrations of sodium and potassiuni in the saliva were determined by flame photometry. The sodium concentrations in the first samples of cat submandibular saliva taken from a previously resting gland were higher than the sodium concentrations in samples taken later at the same secretory rate. The maximal difference in concentration between transient and steady state sample was about 50 meq/l. Steady state concentrations of sodium increased proportionally to the flow rate except at low flow rates where sodium concentrations were greater than expected on the basis of this relation. Steady start concentrations of potassium were independent of the secretory rate when this was higher than 100 μ1/min/g gland, with a value of about 10 meq/l. Below this flow rate the potassium Concentration rose, first slightly and then steeply, when flow rate decreased, and reached values of more than 100 nieq/1 at secretory rates of about 2 μl/min/g gland.