The contribution of nitric oxide to diuretic and natriuretic effects of renal kinins in normotensive rats.
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We have reported that diuresis and natriuresis due to increase in renal kinins induced by the neutral endopeptidase 24.11 (NEP) inhibitor were attenuated by nitric oxide (NO) synthase inhibitor. To further clarify the water-sodium excretory mechanism of renal kinins, we estimated NO2+NO3 (NOx) and cGMP in plasma and urine with and without a specific NEP inhibitor, thiorphan. P-aminohippuric acid (PAH) and inulin were injected into male Sprague-Dawley rats. Vehicle (n = 8) or thiorphan (30 mg/kg, n = 10) was injected after the control period. Mean blood pressure (MBP), plasma and urinary PAH, inulin, NOx and cGMP, urinary volume (UV) and urinary sodium excretion (UNaV) were measured before and after injection of the reagents. MBP, renal plasma flow and glomerular filtration rate were not affected by thiorphan. Plasma NOx and cGMP with thiorphan did not differ from the vehicle, while urinary NOx and cGMP increased. None of the variables were affected by vehicle. UV and UNaV were higher with thiorphan than with vehicle. Positive correlation was found between urinary deltaNOx and deltacGMP. Each urinary deltaNOx and deltacGMP was significantly correlated to both deltaUV and deltaUNaV. Urinary NOx and cGMP were increased while maintaining correlations to UV and UNaV, but plasma NOx and cGMP were not affected by thiorphan. This implies that the mechanism of water-sodium excretion induced by NEP inhibitor is mediated by renal NO. Therefore, renal NO may contribute to the diuretic and natriuretic effects of renal kinins. (+info)
Non-steroidal anti-inflammatory drugs and renal response to exercise: a comparison of indomethacin and nabumetone.
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Nabumetone, a newer non-steroidal anti-inflammatory drug (NSAID) which preferentially blocks cyclo-oxygenase-2 activity, may be less nephrotoxic than indomethacin. This study tested whether nabumetone has effects different from those of indomethacin on exercise-induced changes in renal function and the renin-aldosterone system. In a randomized fashion, ten subjects were studied after indomethacin (100 mg), nabumetone (1 g) or no medication (control) administered orally at 22.00 hours on the day before each study day, and again at 8.00 hours upon arrival at the laboratory. Renal function was studied at baseline, during graded 20-min exercise sessions at 25%, 50% and 75% of the maximal oxygen uptake rate, and subsequently during two 1-h recovery periods. Heart rate, arterial blood pressure, cardiac output and plasma catecholamines at rest and during exercise were not altered by indomethacin or nabumetone. Indomethacin decreased urinary rates of excretion of 6-oxo-prostaglandin F(1alpha) (6-oxo-PGF(1alpha)) and thromboxane B(2) in all study periods. Nabumetone decreased 6-oxo-PGF(1alpha) excretion during and after exercise. Excretion rates for PGE(2) did not change. Neither indomethacin nor nabumetone changed baseline values or exercise-induced decreases in renal plasma flow or glomerular filtration rate. Indomethacin, but not nabumetone, decreased sodium excretion, urine flow rate and free water clearance. The renal response to exercise, however, remained unchanged. In contrast with nabumatone, indomethacin decreased the plasma renin concentration. Thus, during exercise, nabumetone may decrease the excretion of 6-oxo-PGF(1alpha) by inhibition of cyclo-oxygenase-1 or by inhibition of specific exercise-induced activation of cyclo-oxygenase-2, or both. None of the drugs changed the renal response to exercise. Inhibition by indomethacin of angiotensin II and thromboxane A(2) synthesis may, during exercise, counterbalance renal vasoconstriction caused by blockade of vasodilatory prostaglandins. (+info)
Translabial color Doppler for imaging in urogynecology: a preliminary report.
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OBJECTIVE: A prospective study was conducted to evaluate the use of color Doppler ultrasound in the investigation of female urinary incontinence. METHODS: Thirty-seven patients underwent a full urodynamic assessment and translabial ultrasound examination using color Doppler-capable equipment with 5-7-MHz curved array transducers, both in the supine and in the erect positions. RESULTS: More than minimal leakage was seen in 13 patients by Doppler and in 16 by fluoroscopic imaging. Results were in agreement in 28/37 cases (kappa 0.49). The observed discrepancies may have been due to initial technical difficulties, differences in bladder filling and the presence of a catheter on fluoroscopic imaging. In five incontinent patients, urethral flow velocities ranged from 0.064 to 0.34 m/s, which is equivalent to physiological venous and slow arterial blood flow and one to two orders of magnitude above the detection threshold of standard Doppler ultrasound equipment. CONCLUSIONS: Translabial color Doppler imaging of the lower urinary tract allows the documentation of fluid leakage from the bladder. It has the potential to become the new imaging standard for urogynecology. (+info)
Urinary function in elderly people with and without leukoaraiosis: relation to cognitive and gait function.
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OBJECTIVES: To investigate urinary function in the elderly with and without white matter lesion (leukoaraiosis) in relation to cognitive and gait function. METHODS: Sixty three subjects were examined, with mean age 73 (range 62 to 86 years). Subjects with brainstem stroke or with large hemispheric lesions were excluded. Spin echo 1.5 T MRI images were graded from 0 to 4 for severity of white matter lesions. Urinary function was assessed by detailed questionnaire and urodynamic studies were performed in 33 of the subjects, including measurement of postmicturition residuals, water cystometry, and sphincter EMG. A mini mental state examination (MMSE) and examination of gait was also performed and compared with urinary function. RESULTS: Urodynamic studies showed subjects with grade 1-4 white matter lesions to have detrusor hyperreflexia more commonly (82%) than those with grade 0 white matter lesions (9%) (p<0.05), indicating that leukoaraiosis was a factor associated with geriatric urinary dysfunction. Postmicturition residuals, low compliance, detrusor-sphincter dyssynergia, and uninhibited sphincter relaxation were also more common in grade 1-4 than in grade 0 white matter lesions, though the difference was not significant. In grade 1 white matter lesions urinary dysfunction (urge urinary incontinence) was more common than cognitive (MMSE<19) (p<0.05) and gait disorders (slowness, short step/festination, and loss of postural reflex) (p<0. 05), which increased together with the grade of white matter lesions (p<0.05). CONCLUSIONS: Urinary dysfunction is common and probably the early sign in elderly people with leukoaraiosis on MRI. (+info)
Effects of beta-adrenergic stimulation on the acutely obstructed ureter in dogs.
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The objective of the present study was to evaluate the effects of a selective beta(3)-adrenoceptor agonist, (R, R)-5-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]-amino]propyl]-1, 3-benzodioxole-2,2-dicarboxylate (CL 316243), on the acutely obstructed ureter in anesthetized dogs. After a complete ureteral obstruction produced by the inflation of a balloon catheter placed within the left lower ureter, the intraluminal ureteral pressure gradually rose to reach a plateau of approximately 52.5 mm Hg. Intravenous administration of isoproterenol (a nonselective beta-adrenoceptor agonist; 10 microg/kg) and CL 316243 (1 microg/kg) significantly decreased this elevated ureteral pressure (by 74.1 and 77.2%, respectively), with the reduction more sustained with CL 316243 than with isoproterenol. In addition, under both isoproterenol and CL 316243, urine flow (which had been interrupted by the balloon) was resumed, resulting in further sustained decreases in ureteral pressure. The mean blood pressure decreased and heart rate increased after the administration of both drugs, but these changes were greater in the isoproterenol group than in the CL 316243 group. In contrast, i.v. administration of butylscopolamine (an anticholinergic agent; 1000 microg/kg) had no evident effects on ureteral pressure or on urine flow. The increase in left kidney weight seen after ureteral obstruction was suppressed by CL 316243. We conclude that the selective beta(3)-adrenoceptor agonist tested appears to be more useful than isoproterenol for reducing ureteral pressure above the obstructed site and for promoting ureteral relaxation and increasing urine flow around the point of obstruction in dogs. (+info)
The influence of salinity and temperature change on the functioning of the urinary bladder in the early larval stages of the atlantic herring Clupea harengus L.
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Major changes in the morphology of the urinary bladder were observed during the transition from yolk-sac to feeding larval stages of herring, in particular bladder volume increased almost sixfold. Initially, the urine flowed into the hindgut, but within days of hatching a separate urinary duct, leading to the exterior, had formed. Micturation was intermittent but quite regular. The period between micturations increased from 1.6 to 4 min in the progression between the two larval stages. The discharge volume was approximately 50 % of the full bladder volume in all stages studied. Urine flow rate (UFR) in sea water rose slightly from 1 to 1.7 nl mg(-)(1 )h(-)(1) during early larval development. Exposure to low salinities significantly reduced UFR in yolk-sac larvae, but in the later stages UFR increased significantly in hypo-osmotic salinities, so that UFR in 4 salinity was 2.5 times that in 34 salinity. The main variable influencing UFR was discharge frequency. Cardiac output was not influenced by salinity and was considered not to be a controlling factor in the UFR response to salinity change. UFR increased with temperature with Q(10) of 2.3 in stage 1 larvae and 1. 5 in stage 2 larvae, over 7-15 degrees C. (+info)
Abnormal water metabolism in mice lacking the type 1A receptor for ANG II.
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Mice lacking AT(1A) receptors for ANG II have a defect in urinary concentration manifested by an inability to increase urinary osmolality to levels seen in controls after thirsting. This defect results in extreme serum hypertonicity during water deprivation. In the basal state, plasma vasopressin levels are similar in wild-type controls and Agtr1a -/- mice. Plasma vasopressin levels increase normally in the AT(1A) receptor-deficient mice after 24 h of water deprivation, suggesting that the defect in urine concentration is intrinsic to the kidney. Using magnetic resonance microscopy, we find that the absence of AT(1A) receptors is associated with a modest reduction in the distance from the kidney surface to the tip of the papilla. However, this structural abnormality seems to play little role in the urinary concentrating defect in Agtr1a -/- mice since the impairment is largely reproduced in wild-type mice by treatment with an AT(1)-receptor antagonist. These studies demonstrate a critical role for the AT(1A) receptor in maintaining inner medullary structures in the kidney and in regulating renal water excretion. (+info)
Lower urinary tract function after intra-arterial chemotherapy with concurrent pelvic radiotherapy for invasive bladder cancer.
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BACKGROUND: Intra-arterial chemotherapy with concurrent pelvic radiotherapy as a bladder-sparing regimen for invasive bladder cancer is highly promising for selected patients. However, lower urinary tract function after this treatment has not been fully investigated. METHODS: The urodynamic effects of intra-arterial chemotherapy with concurrent pelvic radiotherapy were retrospectively evaluated in 14 patients with organ-confined invasive bladder cancer. The post-treatment urodynamic findings were compared with the pretreatment ones (n = 7), and a comparison was made between the serial urodynamic findings after the treatment in another seven patients who were able to undergo the pretreatment urodynamic study (UDS). RESULTS: The median follow-up period up to the latest UDS was 34 months. Of the 14 patients, the latest UDS revealed some storage dysfunctions in 11 (79%) and some emptying dysfunctions in three (23%). Uninhibited detrusor contraction and decreased bladder compliance were recorded in 29 and 43% at the pretreatment UDS and approximately 50-60 and 20-60% in the serial follow-up studies, respectively (n = 7). Impaired detrusor contractility lasted in one patient. In the seven patients without the pretreatment UDS, decreased maximum cystometric capacity and decreased compliance were recorded in approximately 50-60 and 20-60% at the serial UDS, respectively. Detrusor contractility was aggravated in one patient and completely lost in one with time. CONCLUSIONS: The urodynamic findings indicate that the bladder-sparing regimen might result in perpetuating the lower urinary tract dysfunctions due to invasive bladder cancer itself and/or transurethral surgery and might injure the infrasacral autonomic nerves and the bladder itself. (+info)