Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of acetazolamide on calcium metabolism was examined using sham-operated, ureter-ligated and nephrectomized rats. Acetazolamide doses from 10 to 500 mg/kg produced significant hypocalcemic effects in ureter-ligated and nephrectomized rats. However, doses of acetazolamide up to 1000 mg/kg were devoid of hypocalcemic activity when administered to sham-operated rats. Sham-operated rats exhibited an acidotic response to acetazolamide while ureter-ligated rats did not. Attenuation of this drug-induced acidotic response with i.p. injections of tris(hydroxymethyl)amino-methane uncovered a hypocalcemic effect of acetazolamide in sham-operated rats. Also, the hypocalcemia associated with acetazolamide treatment of ureter-ligated rats was negated when an acidosis was induced by prior injection of NH4Cl. These data indicate that the administration of inhibitors of carbonic anhydrase produces a hypocalcemia when a metabolic acidosis is not present.
 ...
PMID:Acidosis inhibits the hypocalcemic effect of acetazolamide. 4 35

Spontaneous contractions were elicited by microvibrations (1--80 Hz, 50--400 micron) imposed upon quiescent ureter and portal venous smooth muscles of dogs. The microvibrations increased the rate of spontaneous contractions. A microvibration of larger amplitude gave rise to a more profound increase at each frequency. The acceleration was often accompanied by a reduction in contractile force. The positive chronotropic effect was enhanced by increases in frequency from 20 to 40 Hz and not affected by administration of autonomic blocking agents and tetrodotoxin, but disappeared in a Ca-free environment and reappeared on addition of Ba2+. the simulating action of microvibration was almost proportional to external Ca2+ concentrations ranging from 2.2 to 6.2 mM. The microvibrations were able to elicit spontaneous activity in the preparation, which had been made quiescent by administration of Mn2+. These findings suggested that the positive chronotropic effect may be closely related to an increased Ca2+ influx through the membrane of smooth muscle. Active tension in the ureter in a state of contracture was depressed by imposed microvibrations.
 ...
PMID:Effect of microvibration on activity of ureteral and portal smooth muscles. 44 63

Computerized tomography demonstrated that a non-opaque filling defect within the ureter of a ureterostomy patient was a struvite calculus containing a minimal amount of calcium salts.
 ...
PMID:Non-opaque calculus demonstrated by computerized tomography. 50 32

In isolated muscle strips of porcine renal pelvis and ureter, the calcium antagonist nifedipine (3.10(-7) moles/l) completely suppressed spontaneous phasic mechanical activity and the phasic components of an adrenaline-induced activation (P-component). In the presence of nifedipine, adrenaline induced in pelvis preparations (but not in the ureter) a tonic contraction (T-component) which was on average 61% of the control reaction (SD +/- 26%; n = 35).
 ...
PMID:A tonic component in the motility of the upper urinary tract (renal pelvis-ureter). 62 Jul 39

Changes in the excretion of water and electrolyte in one kidney after exclusion of its partner have been studied in anesthetized dogs and rabbits. Complete clamping of the contralateral kidney pedicle or ureter results in a rapid increase in the excretion of water, sodium, potassium, chloride, calcium, phosphate and bicarbonate. This response is also observed in denervated kidneys. Pretreatment with the loop inhibitor, furosemide, does not preclude adaptation which, however, is blunted by acetazolamide, an inhibitor of proximal sodium and bicarbonate reabsorption. Free-water reabsorption during hypertonic saline diuresis is normal in the remaining kidney. Compensatory adaptation, thus, appears to be located in the proximal tubule. The regulatory response to contralateral kidney exclusion is already fully developed in one-month-old rabbits. Compensatory adaptation of electrolyte excretion is not accounted for by changes in extracellular fluid volume, plasma composition, glomerular filtration rate, effective renal plasma flow, aldosterone or vasopressin.
 ...
PMID:Studies on compensatory adaptation of renal functions. 73 47

Experiments were performed on the smooth muscle cells of the guinea pig ureter by means of the double sucrose-gap method. An increase of Ca2+ concentration (22 mM/1) in Ringer-Locke solution causes hyperpolarization and a slight increase of the membrane resistance. The amplitude of the first spike potential and the plateau decreases, the amplitude of oscillations increases. In sodium-free Ringer-Locke solution when the action potential in the smooth muscle cells of the ureter turns into a simple spike potential, an increase of Ca2+ concentration causes a marked increase of the action potential amplitude.
 ...
PMID:[Effect of increased calcium ion concentration on the electrical and contractile activity of guinea pig ureter smooth muscle]. 88 49

Prostaglandin E1 (PGE1) hyperpolarized the smooth muscle cells of guinea-pig ureter in normal Krebs solution and was without effect on ureters depolarized in KCl Krebs, PGE1 inhibited both electrically induced contractions and K+-induced contractures of the ureters. Conditions that favored greater tension development by the ureters, namely, high [K+] or high [Ca-2+] reduced the inhibitory effects of PGE1 on the K+-induced contractures. Depolarization of guinea-pig ureter with KCl Krebs led to an increase in radio-calcium content of the tissue over a 30 min loading period. This increase in the tissue's radio-calcium content was further increased by PGE1 but not by theophylline, PGE1 was found to have no effect on either total calcium content or the calcium efflux from the tissue. It is suggested that PGE1 exerts its inhibitory action by increasing calcium sequestration at the inner surface of the cell membrane.
 ...
PMID:The inhibitory effects of prostaglandin E1 on guinea-pig ureter. 113 21

Low calcium concentration in the external medium depolarises the membrane of smooth muscle cells of the ureter and their excitability diminishes. The Ca++ dependent oscillations of the action potential disappears, while the plateau component is more resistent. Analogous reactions are observed by the addition of Ca++ antagonists such as Lantanum or Verapramil. A high Calcium concentration produces a slight hyperpolarisation, which stabilises the membrane and enhances the spike component while decreasing the plateau component of the action potential. It is possible that several drugs act indirectly on the ureter by changing the relationship between the calcium concentration of the external versus the internal medium.
 ...
PMID:The influence of calcium on the electrical and mechanical activity of the guinea pig ureter. 120 89

Between August 1987 and December 1990, 546 patients were admitted to the department of Urology at the Poh Ai Hospital of I-Lan, Taiwan, R.O.C. for the treatment of urinary stones. These urinary stone cases accounted for 50 to 60% of all urology patients admitted. The incidence of urolithiasis in I-Lan was estimated at 147/100,000 population in 1990. There were 402 male patients and 144 female patients, The male to female ratio was 2.8: 1. There were 450 upper urinary tract stones (kidney, ureter) in 314 males and 136 females, and 79 lower urinary tract stones (bladder, urethra) in 72 males and 7 females. The ratio of upper to lower urinary tract stones was 6:1. Endourological treatments such as percutaneous nephrolithotripsy and transurethral ureterolithotripsy have increased rapidly in recent years. A summary of the present analysis for composition of 365 stones follows. The most frequent type was calcium-containing stone (92.3%), followed by infection stone (4.7%), then uric acid (UA) stone (3.0%). There were no UA stones found in the female patients. According to urinalysis criteria of more than 10 WBC/HPF (x 400), pyuria was found in 67 cases of 334 metabolic stones (20.1%), and 11 cases of 17 infection stones (67.7%). There were neither pediatric case of stone formation nor cystine stones.
 ...
PMID:[Clinical analysis of urolithiasis in Poh Ai Hospital of I-Lan, Taiwan, R.O.C.--a comparative study with urolithiasis in Japan]. 128 22

Previous in vitro experiments demonstrated the reduced microhardness of calcium oxalate monohydrate (COM) calculi, relative to dry values, when saturated with an alkaline solution (pH = 9.5). Nineteen patients with a COM calculus in the distal ureter which had been resistant to prior extracorporeal shock wave lithotripsy in situ, were treated when the stone was surrounded by alkaline urine. The urine of 14 patients was alkalinized orally by administration of acetazolamine and citrate solution; in 5 other patients direct percutaneous irrigation of sodium bicarbonate via a nephrostomy tube was carried out. The urinary pH just before lithotripsy was greater than or equal to 9 in 17/19 patients. 4,000 shock waves, averaging 18.1 kV generated by the Siemens Lithostar, were delivered onto the calculus. No significant increase of comminution rate was apparent at radiographic control immediately after the treatment and only in half of the cases was evacuation obtained within 3 months.
 ...
PMID:Effect of alkalinization on calcium oxalate monohydrate calculi during extracorporeal shock wave lithotripsy: in vivo experiments. 131 63


1 2 3 4 5 6 7 8 9 10 Next >>