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Urinary Volume (urinary + volume)
Selected AbstractsCentral nitric oxide blocks vasopressin, oxytocin and atrial natriuretic peptide release and antidiuretic and natriuretic responses induced by central angiotensin II in conscious ratsEXPERIMENTAL PHYSIOLOGY, Issue 5 2007Wagner Luis Reis The presence of nitric oxide synthase (NOS), the enzyme that catalyses the formation of nitric oxide (NO), in the circumventricular organs and magnocellular neurones suggests an important role of NO in the modulation of vasopressin (AVP) and oxytocin (OT) release. Intracerebroventricular (i.c.v.) injection of angiotensin II (Ang II) stimulates the release of AVP, OT and atrial natriuretic peptide (ANP), with the resultant antidiuretic and natriuretic effects. This study investigated the interaction between nitrergic and angiotensinergic pathways on the release of AVP, OT and ANP and on urinary volume and sodium excretion in water-loaded rats. Unanaesthetized, freely moving, male Wistar rats received two water loads followed by an injection into the lateral ventricle of an inhibitor of NOS (l -NAME), a NO donor [3-morpholinylsydnoneimine chloride (SIN-1) or S -nitroso- N -acetyl penicillamine (SNAP)] or vehicle (isotonic saline) and, 20 min after, they received a second i.c.v. injection of Ang II or vehicle. Injections of l -NAME or Ang II produced an increase in plasma levels of AVP, OT and ANP, a reduction in urinary volume and an increase in sodium excretion. Pretreatment with l -NAME enhanced the Ang II-induced increase in AVP, OT and ANP release, as well as the antidiuresis and natriuresis. Injection of SIN-1 or SNAP did not modify hormonal plasma levels and urinary parameters. In contrast SNAP blocked the AVP, OT and ANP release, as well as antidiuretic and natriuretic responses induced by ANG-II. Thus, the central nitrergic system can act to inhibit AVP, OT and ANP secretion and the antidiuretic and natriuretic effects in response to Ang II. [source] Lack of renal improvement with nonselective endothelin antagonism with tezosentan in type 2 hepatorenal syndrome,,HEPATOLOGY, Issue 1 2008Florence Wong Renal vasoconstriction is a key factor in the development of hepatorenal syndrome (HRS) and may be secondary to increased activities of endothelin-1, a potent renal vasoconstrictor. To assess the effects of tezosentan, a nonselective endothelin receptor antagonist, on renal function in patients with type 2 HRS, six male patients, 56.3 ± 2.5 years old, with cirrhosis and type 2 HRS were treated with tezosentan; ascending doses of 0.3, 1.0, and 3.0 mg/hour, each for 24 hours, were used for the initial 2 patients, but a constant dose of 0.3 mg/hour for up to 7 days was used for the remaining 4 patients. The glomerular filtration rate, renal plasma flow, 24-hour urinary volume, mean arterial pressure (MAP), heart rate, tezosentan levels, and vasoactive hormones were measured daily. Albumin was given as required. The study was stopped early because of concerns about the safety of tezosentan in type 2 HRS. Five patients discontinued the study early; one stopped within 4 hours because of systemic hypotension (MAP < 70 mm Hg), and 4 patients stopped at ,4 days because of concerns about worsening renal function (serum creatinine increased from 180 ± 21 to 222 ± 58 ,mol/L, P > 0.05) and decreasing urine volume (P = 0.03) but without a significant change in MAP. The plasma tezosentan concentrations were 79 ± 34 ng/mL at a steady state during infusion at 0.3 mg/hour. The plasma endothelin-1 concentrations increased from 2.7 ± 0.3 pg/mL at the baseline to 19.1 ± 7.3 pg/mL (P < 0.05). Conclusion: An endothelin receptor blockade potentially can cause a deterioration in renal function in patients with cirrhosis and type 2 HRS. Caution should be taken in future studies using endothelin receptor antagonists in these patients. (HEPATOLOGY 2007.) [source] Reduction in nocturnal functional bladder capacity is a common factor in the pathogenesis of refractory nocturnal enuresisBJU INTERNATIONAL, Issue 3 2002C.K. Yeung Objective,To evaluate the diurnal and nocturnal bladder reservoir function in patients with refractory primary nocturnal enuresis (PNE). Patients and methods,Ninety-five children (68 boys, 27 girls, mean age 9.3 years) with significant PNE (3 wet nights/week) that was refractory to treatment with desmopressin ± an enuretic alarm were assessed using detailed recording of voiding frequency and urinary volume both day and night, natural filling cystometry during the day and continuous cystometry with simultaneous electroencephalogram monitoring during sleep at night. Results,Patients could be broadly categorized into two groups. Group A comprised those with normal daytime urodynamics and functional bladder capacity (FBC) on detailed frequency-volume recording, but who developed marked detrusor instability associated with a significant reduction in nocturnal FBC and small-volume voiding only after sleep at night (33 patients, 35%); and group B, those with abnormal daytime urodynamics and with reduced FBC and small-volume voiding both day and night, but who somehow managed to mask their bladder symptoms during the day (62 patients, 65%). There was no evidence of nocturnal polyuria in either group and the ratios of day,:,night urinary output volumes for type A and type B patients were 1.48 and 1.99, respectively. Conclusions,A reduction in nocturnal FBC, either occurring only after sleep at night in association with the appearance of detrusor instability in patients with normal daytime urodynamics and FBC, or as a manifestation of occult voiding dysfunction or bladder outlet obstruction that affects the bladder reservoir function both day and night, appears to be a common factor and probably the main cause for a mismatch between nocturnal urine output and bladder storage capacity in patients with severe bed-wetting that was refractory to treatment. [source] Renal concentrating capacity as a marker for glomerular filtration rateACTA PAEDIATRICA, Issue 1 2008Víctor M García Nieto Aim: We have studied 160 children with a variety of renal diseases, 14 of them with chronic renal failure (CRF), to evaluate maximum urinary osmolality as a predictor of glomerular filtration rate (GFR) testing the hypothesis that a normal GFR is necessary to have a normal urinary concentrating capacity. Methods: All patients had a serum creatinine measured. GFR was calculated according to the Schwartz formula. All patients underwent desmopressin (DDAVP) test to evaluate renal concentrating capacity. Results: Patients with CRF were unable to concentrate the urine beyond 486 mosm/kg whereas all patients with a normal concentrating capacity (urine osmolality > 835 mosm/kg) had a normal GFR. Desmopressin test sensitivity to detect CRF was 100% and specificity 70.5%. A significant negative correlation was found between urinary osmolality after DDAVP administration and serum creatinine levels and between urinary volume corrected by 100 mL of GFR (V/GFR) and urinary osmolality. Conclusion: In our series, a normal concentrating capacity was always associated with a normal GFR while all patients with decreased GFR had a concentrating capacity defect. Thus, in the evaluation of infants and children with renal disease, the finding of a normal urinary concentrating capacity will suggest and intact glomerular and tubular function. [source] The relationship of magnesium intake to serum and urinary calcium and magnesium levels in Trinidadian stone formersINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2005TREVOR I ANATOL Abstract, Background:, The present study was undertaken to investigate the relationship between the dietary intake of magnesium and the serum and urinary levels of calcium and magnesium in a group of Trinidadian stone formers. Methods:, A group of 102 confirmed stone formers presenting to urological clinics were interviewed using a questionnaire designed to obtain a semi-quantitative estimate of their oral magnesium intake. Patients were invited to give blood samples for serum calcium and magnesium levels and to provide 24-h urine specimens for the measurement of urinary levels of these minerals, as well as total urinary volumes. A group of 102 controls was subjected to a similar interview and blood and urinary testing. Chi-square tests and Student's t -tests were used to examine group demographic differences. The Mann,Whitney test investigated differences in biochemical indices. Binary logistic regression was used to identify predictors of stone formation. Results:, Blood samples were obtained from 60 patients and 98 controls. Urine samples were returned by 34 patients and 97 controls. Only 10 stones were retrieved from patients. Patients had a significantly lower magnesium intake, but higher median serum and urinary calcium levels, and higher serum calcium to magnesium ratios than controls. Independent variables capable of predicting stone formation included total magnesium intake and serum and urinary calcium levels. Conclusions:, Increased serum and urinary calcium levels, calcium to magnesium ratios, and a low magnesium intake were predictive of stone formation in this Trinidadian population. [source] | ||||||||||