Search results for "Potassium"
showing 10 items of 930 documents
Urinary tetrahydroaldosterone as a screening method for primary aldosteronism: a comparative study
2003
Abstract Background The major aldosterone metabolite 3α,5β tetrahydroaldosterone reflects up to 45% of the aldosterone secretion. Its 24-h urinary excretion is likely to provide an accurate index of the daily aldosterone production and to be an indicator for primary aldosteronism (PA). Methods In a prospective study, the validity of tetrahydroaldosterone as a screening test for PA was evaluated in comparison to serum potassium, plasma aldosterone, plasma renin activity, plasma aldosterone/renin activity ratio (PARR), as well as 24-h urinary aldosterone-18-glucuronide and free aldosterone. A total of 111 normotensive individuals, 412 PA patients and 1453 essential hypertensive patients, were…
Sarcolemmal excitability as investigated with M-waves after eccentric exercise in humans
2006
It has been shown that intensive eccentric muscle actions lead to prolonged loss of muscle force and sarcolemmal damage. This may lead to a reduction in the excitability of the sarcolemma and contribute to the functional deficit. Experiments were carried out to test sarcolemmal excitability after eccentric elbow flexor exercise in humans. Electrically elicited surface compound muscle action potential (M-wave) properties from 30s stimulation trains (20Hz) were analyzed in biceps brachii muscle immediately after, 1h and 48h after the exercise. M-wave area, amplitude, root mean square and duration were reduced immediately after the eccentric exercise. However, no such reduction could be observ…
Role of Ca2+-activated K+ channels and Na+,K+-ATPase in prostaglandin E1- and E2-induced inhibition of the adrenergic response in human vas deferens
2011
We studied the role of K(+) channels and Na(+),K(+)-ATPase in the presynaptic inhibitory effects of prostaglandin E(1) (PGE(1)) and PGE(2) on the adrenergic responses of human vas deferens. Furthermore, we determined the effects of increasing extracellular K(+) concentrations ([K(+)](o)) and inhibition of Na(+),K(+)-ATPase on neurogenic and norepinephrine-induced contractile responses. Ring segments of the epididymal part of the vas deferens were taken from 45 elective vasectomies and mounted in organ baths for isometric recording of tension. The neuromodulatory effects of PGEs were tested in the presence of K(+) channel blockers. PGE(1) and PGE(2) (10(-8) to 10(-6)M) induced inhibition of …
Endothelium-dependent responses in human isolated thyroid arteries from donors
2004
The functional properties of the endothelium of human thyroid arteries remain unexplored. We investigated the intervention of nitric oxide (NO), prostacyclin (PGI(2)) and endothelium-derived hyperpolarizing factor (EDHF) in the responses to acetylcholine and noradrenaline in isolated thyroid arteries obtained from multi-organ donors. Artery rings were suspended in organ baths for isometric recording of tension. The contribution of NO, PGI(2) and EDHF to endothelium-dependent relaxation was determined by the inhibitory effects of N(G)-monomethyl-L-arginine (L-NMMA), indomethacin, and K(+) channel inhibitors respectively. Acetylcholine induced concentration-dependent relaxation; this effect w…
Modulation of adrenergic responses of human vas deferens by K+ channel inhibitors.
2010
Objectives The present study was designed to evaluate the role of K + channels in the adrenergic responses of human vas deferens as well as the intervention of dihydropyridine-sensitive Ca 2+ channels on modulation of adrenergic responses by K + channel inhibitors. Methods Ring segments of the epididymal part of the vas deferens were taken from 32 elective vasectomies and mounted in organ baths for isometric recording of tension. We then studied the effects of K + channel blockers on neurogenic and norepinephrine-induced contractile responses. Results Addition of tetraethylammonium (TEA, 10 −3 M), a nonspecific K + channel blocker, or charybdotoxin (10 −7 M), a nonselective inhibitor of lar…
Nitric oxide mediates abnormal responsiveness of thyroid arteries in methimazole-treated patients.
2005
Objective: We studied the intervention of nitric oxide (NO), prostacyclin and endothelium-derived hyperpolarizing factor (EDHF) in mediating responses to acetylcholine in thyroid arteries from euthyroid and methimazole-treated (MT) patients. Design and methods: Branches of the superior thyroid artery were obtained from 19 euthyroid patients and 17 MT patients (euthyroid at the time of surgery) undergoing total thyroidectomy or hemithyroidectomy. Artery rings were suspended in organ baths for isometric recording of tension. Results and conclusions: Acetylcholine caused endothelium-dependent relaxation of greater magnitude in arteries from MT patients (pD2 (−log EC50) values were 7.68±0.19 in…
Contemporary Management of Struvite Stones Using Combined Endourologic and Medical Treatment: Predictors of Unfavorable Clinical Outcome
2016
Struvite stones have been associated with significant morbidity and mortality, yet there has not been a report on the medical management of struvite stones in almost 20 years. We report on the contemporary outcomes of the surgical and medical management of struvite stones in a contemporary series.A retrospective review of patients who were treated with percutaneous nephrolithotomy (PCNL) for struvite stones at Duke University Medical Center between January 2005 and September 2012 identified a total of 75 patients. Of these, 43 patients had adequate follow-up and were included in this analysis. Stone activity, defined as either stone recurrence or stone-related events, and predictors of acti…
Whole-body potassium and bone mineral density up to 30 years after urinary diversion
1998
Objectives To evaluate the long-term effects of different types of urinary diversion on skeletal bone density and whole-body potassium content in patients with an early correction of base excess (<−2.5). Patients and methods The early correction of base excess (<−2.5) is one of the principles of the treatment of patients undergoing urinary diversion at our institution. In 27 patients with urinary diversion, bone mineral density (assessed by dual-photon absorptiometry), whole-body potassium, electrolyte and creatinine levels were determined, and capillary blood gas analysed. The mean time since surgery was 16.8 years in 16 patients with a rectal reservoir, 20.5 years in six patients with a…
The importance of citrates in treatment and prophylaxis of calcium oxalate urinary stones
2017
About 10% of the people is the subject of an episode of kidney stones during their lifetime, about 70% of these people undergoes relapses. About 80% of the urinary stones contains calcium, of wich 80% is formed of calcium oxalate, in pure form or associated with calcium phosphate. Therefore we can saythat in most cases (about 65%) the urinary stones are composedof calcium oxalate. Use of supplements of potassium citrate and magnesium citrate can help in the prevention of kidney stones of calcium oxalate, but mostly they can be used in the days before a shockwaves lithotripsy treatment to make the stones more fragile to the effect of the shock waves. A case of successful treatment with magne…
Enhancement by vasopressin of adrenergic responses in human mesenteric arteries.
1997
Vasopressin not only acts directly on blood vessels through V1-receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vitro and in vivo. The aim of the present study was to investigate whether subpressor concentrations of vasopressin could modify the constrictor responses to norepinephrine and electrical stimulation of the perivascular nerves in human mesenteric arteries. Human mesenteric artery rings (3-3.5 mm long, 0.8-1.2 mm OD) were obtained from 38 patients undergoing abdominal operations. The arterial rings were suspended in organ bath chambers for isometric recording of tension. Vasopressin (3 x 10(-11) M) enhanced the contractions elicited…