Sodium-24: study body electrolytes

These findings are in accordance with Chua et al study in the volume depleted female Sprague-Dawley rat [106]. Rats were injected intramuscularly with five times the human dose of TMP-SMZ (100/500 mg/kg/ day) for nine days. Prior to treatment, the animals were placed in a low sodium diet for seven days and salt depleted by means of administration of furosemide (2 mg/kg/day) for the first three days. At baseline, experimental and control (glucose given instead of TMP-SMZ) groups have similar GFR, serum creatinine, and hematocrit and were conserving sodium maximally. Nine days of TMP-SMZ did not affect GFR, serum creatinine or electrolyte levels. Loss of body weight and anemia only developed in the rats treated with TMP-SMZ. In this study performed in female rats, known to have a lower tubular secretion of creatinine [107,108], TMP did not appear to decrease the tubular secretion of creatinine. 

Since the early days of analytical applications of ion-selective electrodes they have been used in clinical analysis. The progress in construction and miniaturisation of electrodes as well as contemporary development of computerised potentiometric apparatus have led to the production of automatic analyzers designed especially for clinical applications/ The high degree of response selectivity of the membrane sensors used today eliminates practically the mutual interaction of various blood, serum, plasma or urine components. Nevertheless when drugs or their metabolites are introduced into the body they in some cases may influence the electrode response and cause errors in estimation of the content of the ions present naturally, i.e., potassium, sodium, calcium and chloride. Such parasitic effects may be caused by the interaction of drugs with the electrode membrane. The aim of this study was to check whether some selected drugs can influence the determination of the above mentioned electrolyte ions in the serum. 

Charlie Code reached his concept of the barrier by a different route. In the 1950s Code began to study the absorption of water, sodium, and potassium in the stomach and small intestine. At that time it was well known, chiefly as the result of the work of Maurice Visscher at the University of Minnesota, that there are unidirectional fluxes across the mucosa and that net flow of water and electrolytes is the result of two opposing fluxes. Visscher had said that flux from lumen to blood is out of the gut and that flux from blood to lumen is into the gut (Fig. 7-1 A). Anyone who has studied embryology knows that the lumen of the gut is outside the body and that Visscher s designation of directions is anatomically incorrect. The confusion was compounded by those who studied fluxes across everted sacs of intestine for them, out was from fluid outside the sac, and in was into fluid inside the sac. In 1960 Code proposed unambiguous nomenclature for unidirectional and net fluxes (Fig. 7-1Code s terms were not universally adopted, but I will use them here. 

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