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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Renal cortex homogenates from aged (greater than 5 y) rabbits showed decreased specific activities of brush border membrane enzymes compared to those from control young (6 m) rabbits but the specific enzyme activities of basolateral membrane, endoplasmic reticulum and mitochondria did not differ between the two groups. The stimulatory effects of parathyroid hormone (PTH) on the Ca(2+)-pump enzyme [(Ca(2+)+Mg2+)-ATPase] activity in kidney cortex homogenates were markedly less in aged rabbits, but the effect of cAMP on this enzyme activity was similar. Moreover, the production of cAMP induced by PTH was markedly less in the renal cortex homogenates from aged rabbits. From these results, we have proposed the following mechanism; aging--decrease in the response of cAMP to PTH in renal cortex--decrease in the stimulatory effect of PTH via cAMP on the Ca(2+)-pump enzyme--decreased reabsorption of Ca2+ from ureter--increased urinary Ca2+ secretion. This pathway may contribute to the worsening of senile osteoporosis.
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PMID:Effects of aging on renal response to parathyroid hormone in vitro. 135 71

Renal and ureteral calculi are treated primarily using extracorporeal lithotripsy, with percutaneous nephrostolithotomy retaining an important role for the treatment of large stones and complex situations. Aspects of pretherapy evaluation are reviewed. The vast majority of calculi 5 mm or less in diameter in the mid and lower ureter will pass spontaneously; in patients with acute ureteral obstruction, lower-osmolar nonionic contrast for urography caused as much discomfort as conventional high-osmolar contrast. Treatment planning for extracorporeal lithotripsy has changed in that internal stenting is no longer routinely recommended. Milk-of-calcium and calyceal diverticular stones respond poorly to extracorporeal lithotripsy. The access route used for percutaneous stone removal varies among investigators. Some advocate an intercostal approach for up to one third of patients; substantial complications occur with placement of a track above the 11th rib. Sepsis develops after percutaneous nephrostomy in up to 21% of patients, but the risk of sepsis can be decreased significantly by the administration of antibiotics during and after the procedure. Complications of extracorporeal lithotripsy include renal hematoma (especially if the patient is hypertensive or is taking aspirin), regional organ injury, and bacteremia. Although originally feared to occur frequently, hypertension occurring after or caused by extracorporeal lithotripsy was not confirmed to be a major problem. The incidence in a 2-year postlithotripsy follow-up was no greater than that for control subjects.
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PMID:Radiology and treatment of urinary tract stone disease. 155 85

A 66-year-old female visited our university hospital with the chief complaint of right lower abdominal pain in July, 1984. Kidney-ureter-bladder roentgenograms disclosed the right ureter stone and several left renal stones. She passed the right ureter stone composed of calcium oxalate. Thereafter, she passed small stones twice and sand stones twice until September, 1985. The stone analysis revealed two of them as silica. Although most patients with silica stones reported in Japan had a history of long-term medication of magnesium trisilicate, this patient had not taken this drug. Silica stones are rare and fifteen cases including the present case have been reported in Japan.
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PMID:[Silica calculi: a case report]. 165 20

1. Inward currents elicited by depolarization from holding potentials of -80 to -10 mV in single smooth muscle cells isolated from stomach fundus of the rat and ureter of the guinea-pig had two components. The initial fast component (Ifi) was activated and mostly inactivated within 1-2 and 10 ms, respectively, at 21 degrees C. The following sustained component (Isi) lasted over 50 and 500 ms in fundus and ureter cells, respectively. Ifi was blocked by tetrodotoxin but not affected by 0.5 microM-mu-conotoxin in both types of cells. Isi was abolished by the substitution of extracellular Ca2+ with Mn2+. 2. The sensitivity of Ifis to TTX was markedly different in fundus and ureter cells. The half-inhibition was obtained at 870 and 11 nM, respectively. The amplitude of Ifi was highly dependent on extracellular Na+ concentration in a solution containing 2.2 mM-Mn2+ and 0 mM-Ca2+ in both cells. It is concluded that Ifis in these cells are TTX-sensitive and mu-conotoxin-insensitive Na+ currents. 3. Some of the kinetics of INa measured at 10 degrees C were markedly different in fundus and ureter cells. The current-voltage relationships for Ifi in fundus and ureter cells had peaks at about -10 and 0 mV, respectively. The voltage dependence of the steady-state inactivation of Ifi was also significantly different in these cell types. The half-inactivation voltages were about -74 and -45 mV, respectively. The recovery time course from inactivation in fundus cells was about 10 times slower than that in ureter at -80 mV, where it was 25 ms. 4. The contribution of Ifi to the rising phase of an action potential was examined using TTX under current clamp mode at 21 degrees C. A fast notch-like potential elicited by a subthreshold stimulus for action potential generation was blocked by TTX in both types of cells. Action potentials elicited by a stimulus around threshold were occasionally suppressed by TTX, whereas an action potential was never observed when extracellular Ca2+ was replaced with Mn2+. 5. In conclusion, the existence of at least two types of Na+ channel currents, which were distinguished by their TTX sensitivity and kinetics, was strongly suggested in smooth muscle cells from the rat fundus and the guinea-pig ureter. INa in these cells may have a physiological role to accelerate the generation of an action potential by triggering a rapid activation of ICa, while not being essential for activation of action potentials.
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PMID:Sodium currents in smooth muscle cells freshly isolated from stomach fundus of the rat and ureter of the guinea-pig. 166 61

The role of sodium in calcium active transport from the ureter muscle, preliminarily enriched in these ions, was studied in large ouabain concentration (10(-4) mmol/l) for complete inhibition of the Na(+)-K(+)-pump. The determination of intracellular concentrations of sodium and calcium ions (by flame photometry and isotopic analysis, resp.) showed that a fast decrease of intracellular calcium content was accompanied by an increase of intracellular sodium. With high sodium ions concentration in medium (above 100 mmol/l), the velocity of the decrease in intracellular calcium content reached the maximal value, the efflux of additional enriched calcium ions occurring within 10-15 min. The decrease of intracellular calcium content was in sigmoidal dependence on the concentration of sodium ions in the medium. The electrogenic Na(+)-Ca(++)-exchange system seems to play a major role in calcium-enriched muscles for the decrease of intracellular calcium content.
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PMID:[The role of the sodium gradient in the efflux of Ca++ ions from the smooth muscle cells of the ureter]. 166 63

1. The effects of tetraethylammonium (TEA) and 4-aminopyridine (4-AP) on membrane currents and on single channel K currents in smooth muscle cells isolated from canine trachea were examined by use of tight seal whole cell- and patch-clamp techniques. 2. Depolarizing current applied through a recording pipette did not elicit an action potential under current clamp. A strong outward rectification was observed. 3. In most cells under voltage-clamp, only an outward current was observed upon depolarization from -60 mV when a pipette solution contained mainly KCl. The outward current consisted of three components; a large initial transient, a following sustained component and an additional component of irregular small transients on the sustained one. The two transient components were almost abolished when extracellular and pipette solutions contained 2.2 mM Cd2+ (0 mM Ca2+) and 10 mM EGTA, respectively. The sustained component was well maintained under these conditions. 4. TEA at low concentrations (less than 1 mM) effectively decreased the transient components and made the outward current smooth; it also suppressed the sustained component at higher concentrations. In outside-out patches, external 1 mM TEA reduced the single channel conductance of Ca-activated K channels by about 87% whereas 3 mM 4-AP did not. 4-AP at low concentrations (less than 3 mM) selectively reduced the sustained component of the outward current. 5. A Ca current recorded after the suppression of outward current by internal Cs+ had a peak of approximately 200 pA at +10 mV (holding potential: -60 mV). The half inactivation voltage in the steady-state was approximately -30 mV. 6. Simultaneous application of 1 mM TEA and 4-AP reduced the outward current and unmasked a Ca current. Under these conditions, an action potential with overshoot was easily elicited under current clamp. 7. It is concluded that the low excitability of canine tracheal smooth muscle cell upon depolarization is due to a large outward K current which consists of Ca-dependent and Ca-independent components. The peak amplitude of the Ca current is similar to that in highly excitable smooth muscle cells such as those of the ureter.
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PMID:Effects of tetraethylammonium and 4-aminopyridine on outward currents and excitability in canine tracheal smooth muscle cells. 169 97

In the guinea pig ureter, substance P-(SP) and calcitonin gene-related peptide-(CGRP) like immunoreactivity (LI) were depleted by systemic capsaicin pretreatment, indicating that they are entirely stored in peripheral endings of primary afferent neurons. Electrical field stimulation (20 Hz, 60 V, 0.5 ms) evoked the simultaneous release of SP- and CGRP-LI from superfused guinea pig ureters which was abolished by tetrodotoxin (0.3 microM). omega-Conotoxin (0.1 microM), a potent blocker of N-type voltage-sensitive calcium channels, reduced by 50-70% the evoked release of both peptides. These findings provide direct neurochemical evidence indicating that conotoxin-sensitive calcium channels play a role in transmitter secretion evoked by antidromic invasion of peripheral terminals of capsaicin-sensitive primary afferents.
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PMID:Neurochemical evidence for the involvement of N-type calcium channels in transmitter secretion from peripheral endings of sensory nerves in guinea pigs. 169 65

In the rat and guinea-pig isolated ureter electrical field stimulation of intrinsic nerves (10 Hz for 10 s) produces transient inhibition of evoked (20 mM KCl or 0.1-1 microM neurokinin A) rhythmic contractions by releasing transmitter(s) from peripheral endings of capsaicin-sensitive primary afferents. The C-terminal fragment of human calcitonin gene-related peptide (8-37) blocked the inhibitory effect of electrical field stimulation as well as that produced by exogenous calcitonin gene-related peptide, while leaving unaffected the inhibitory response to isoprenaline. Human calcitonin gene-related peptide (8-37) was devoid of any inhibitory activity of its own but enhanced the amplitude and frequency of KCl-evoked rhythmic contractions in the rat ureter, probably by antagonizing the inhibitory effect of endogenous calcitonin gene-related peptide released by KCl. Omega conotoxin fraction GVIA, a peptide which possesses a potent blocking activity of N-type voltage-sensitive calcium channels, prevented the inhibitory response to electrical stimulation in the guinea-pig ureter, while leaving the response unaffected in the rat ureter. Conotoxin had no effect toward the inhibition produced by exogenous calcitonin gene-related peptide indicating its prejunctional site of action, demonstrated previously in the guinea-pig ureter [Maggi et al. (1990) Neurosci, Lett. 114, 203-206]. Dermorphin, an amphibian peptide with potent agonist activity on mu-type opioid receptors, inhibited the response to electrical stimulation in the guinea-pig ureter but had no effect in the rat ureter.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The neurotransmitter role of calcitonin gene-related peptide in the rat and guinea-pig ureter: effect of a calcitonin gene-related peptide antagonist and species-related differences in the action of omega conotoxin on calcitonin gene-related peptide release from primary afferents. 171 85

A method has been proposed for the kinetic analysis of the relaxation phase of mechanical response of smooth muscle. The method implies linearization of the entire mechano-kinetic relaxation curve using the coordinates ln[(fm-f)/f]; ln t (where fm and f are the maximal and the actual values of force within the relaxation phase respectively) with subsequent calculation of the maximal amplitude--normalized relaxation rate, Vn. The use of the method is illustrated on ureter, protal vein, vas deferens, myometrium of rat and guinea-pig ureter smooth muscles in a variety of experimental conditions. This method can be applied for the description of the calcium transient decay in the myoplasm measured with Ca-sensitive fluorescent dyes. The method might be useful for identification of the contribution of different energy-dependent Ca-transporting systems involved in the control of relaxation, as well as for screening of the mechanisms of action of different factors which modulate the contraction-relaxation cycle.
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PMID:Kinetic analysis of smooth muscle relaxation. 180 80

Blind ending bifid ureter is a rare anomaly in the urinary tract. This anomaly may result from failure of a premature branch of the ureteral bud to join with the metanephric blastema. A 21-year-old man was admitted with macroscopic hematuria and colic pain in the left flank region. Urinalysis demonstrated hematopyuria and excretory urography suggested bifid ending accessory ureter with a stone on the left side. Surgical exploration showed that the accessory ureter was bifurcated from the left ureter at about 5 mm from the bladder wall and ran parallel with the left ureter. Although dense adhesions to the surrounding tissue existed, the accessory ureter was resected at the site of the junction. It measured 3 cm in length and 1 cm in greatest diameter. The stone found at the tip of the accessory ureter was composed of calcium oxalate (24%) and calcium phosphate (76%). Histological examination revealed that the ureter had all layers of normal ureteral structure and no renal tissue was identified in the specimen resected. During a follow-up period of 22 months after the operation, he was free of urinary tract infection and abdominal pain. Of 77 cases with blind ending bifid ureter reported in the Japanese literature, a ureteral stone was found in the blind branch in only 5 cases.
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PMID:[Blind ending bifid ureter with stone in the blind branch: report of a case]. 185 88


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