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

Adenylate cyclase and phosphodiesterase enzyme activities were demonstrated in rabbit ureter. NaF, 10 mM, caused a 60.9 per cent increase in adenylate cyclase activity. Isoproterenol, 5 X 10-7 to 10-5 M induced a statistically significant dose-dependent increase in adenylate cyclase activity which was suppressed by propranolol, 10-7 M. Theophylline, 5 X 10-5 to 10-2 M, significantly inhibited phosphodiesterase activity. Thus, isoproterenol and theophylline, two agents that can relax ureteral segments previously contracted by a depolarizing concentration of potassium, could presumably increase cyclic AMP levels, isoproterenol by increasing synthesis and theophylline by decreasing degradation.
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PMID:Adenylate cyclase and phosphodiesterase activity in rabbit ureter. 19 62

Although epinephrine stimulates insulin release by activation of beta-adrenergic receptors, its dominant effect (mediated by stimulation of alpha-adrenergic receptors) is an inhibition of insulin secretion that is powerful enough to suppress the secretory activity of insulin's most potent stimulants. The insulin-secretory response to potassium chloride (KCl) infusion, however, is not suppressed; in fact, in ureter-ligated dogs simultaneously infused with 360 microgram. epinephrine per hour and 2 mEq. KCl per kilogram per hour, insulin release is actually increased about threefold (over controls). Propranolol blockade of beta-adrenergic receptors essentially abolishes the insulin response to KCl infusion, with and without epinephrine. It is unlikely that KCl, like epinephrine, provokes insulin release by direct stimulation of the beta-adrenergic receptors of the beta cells of the pancreatic islets. However, potassium in some way enhances the beta adrenergic (secretory) activity of epinephrine and blunts its usually dominant alpha-adrenergic (inhibitory) effect.
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PMID:Epinephrine enhancement of potassium-stimulated immunoreactive insulin secretion. Role of beta-adrenergic receptors. 20 80

Some historical aspects of ureterosigmoidostomy are described, and various techniques are discussed and illustrated. Our own satisfaction with the results when the procedure is done through the open sigmoid colon is expressed. Ureterosigmoidostomy, which has in some surgeons' hands fallen into disuse, will continue to be used and probably should be used more than it is at present. When ureterosigmoidostomy is done meticulous care is important in producing a long submucosal tunnel with direct anastomosis of the ureter to the bowel. Preoperative bowel preparation is mandatory. Patients who have undergone ureterosigmoidostomy should remain on a low chloride diet indefinitely with an adequate supplement of sodium potassium citrate to diminish the dangers of electrolyte imbalance and hyperchloremic acidosis. Careful postoperative management and followup care are vital to success.
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PMID:Ureterosigmoidostomy. 32 3

Smooth muscle preparations of the urethra, bladder, and ureter were obtained from patients undergoing operations for various urological disorders. The urethral preparations were contracted by noradrenaline (0.1-3 microgram . ml-1), prostaglandin F2alpha (1-10 microgram . ml-1), and potassium (127 mM), the bladder preparations by carbacholine (0.004-1 microgram . ml-1), prostaglandin F2alpha (1-10 microgram . ml-1), potassium (127 mM), and barium chloride (3 mM), and the ureter preparations by potassium (127 mM), and barium chloride (3 mM). Irrespective of the mode of activation, pretreatment with nifedipine (0.1 microgram . ml-1) for 10 min. reduced the responses. Nifedipine also relaxed preparations contracted by the contractile agents used. In 19 female patients, aged 20 to 73 years, undergoing investigation because of urgency and/or urge incontinence, simultaneous urethrocystometry at rest was performed before and after oral administration of 20 to 40 mg nifedipine. Bladder capacity and residual urine were also determined. Nifedipine did not affect the pressures within the bladder and urethra, nor did it increase the bladder capacity. However, after nifedipine intake there was a statistically significant increase in residual urine. The results suggest that nifedipine can inhibit contractile activity induced by drugs with different modes of action; the drug does not affect the tone in bladder and urethra.
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PMID:Effects of nifedipine on the smooth muscle of the human urinary tract in vitro and in vivo. 69 40

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.
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PMID:Studies on compensatory adaptation of renal functions. 73 47

The renal and proximal tubule response to contralateral kidney exclusion was studied in a variety of circumstances. Recollection micropuncture studies were performed to assess the response to contralateral kidney clamping in the normal or a remnant kidney of the dog. Acute clamping of the contralateral kidney for a normal and unilateral remnant kidney resulted in marked reduction in proximal TF/P inulin ratios in the experimental kidney reflecting a 15 percent reduction in fluid reabsorption. Mean fractional excretion of sodium, potassium and water increased significantly in remnant kidney dogs but no significant change was observed in normal dogs except for potassium excretion. The marked reduction in proximal reabsorption occurred as soon as 5-15 minutes after contralateral kidney clamping and was compensated by distal reabsorption. Acute obstruction of the contralateral ureter results in a similar markedly reduced proximal tubular reabsorption. The reduction in proximal reabsorption induced by contralateral clamping occurred in the presence of reduced perfusion pressure and volume expansion and to some extent with renal denervation. When prostaglandin E(2) or acetycholine were infused prior to contralateral kidney clamping, proximal reabsorption remained at control levels and the contralateral clamping response was blocked. Similar blockade occurred after treatment with indomethacin. Acute reduction in nephron mass causes a marked depression of proximal tubular sodium and fluid absorption not obviously accounted for by hemodynamicphysical factors and humoral factors may be involved. The level of distal reabsorption to increased proximal delivery following contralateral clamping, determines the net urinary excretion.
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PMID:Acute functional adaptation to nephron loss: micropuncture studies. 73 48

Investigations were conducted with the combination of N1-(4,5-dimethyl-2-oxazolyl)-sulfanilamide (sulfamoxole) and 2,4-diamino-5-(3,4,5-trimethoxy-benzyl)-pyrimidine (trimethoprim) (CN 3123, Nevin, Supristol) in a dose ratio of 5:1, with respect to pharmacological activity and possible side effects. The effects obtained with the combination CN 3123 were compared with those of the single substances. In a dose range comparable to that as used in clinical treatment, there were no effects on cardiovascular or respiratory functions, on functions of autonomic and central nervous system, on contractility of smooth muscles and on data of clinical chemistry such as urine and electrolyte excretion, blood sugar, blood coagulation and liver function tests. Doses which are 5 to 10 times higher than the initial dose or 10 to 20 times higher than the maintenance dose used in man caused an increase of urine and sodium excretion without influencing potassium and chloride output. There were no signs of sedation as alteration of motility or EEG patterns, but in mice and rats there was an increase in both duration and depth of anaesthesia caused by barbiturates or ether. Only in a dose range 30 to 40 times higher than the initial dose for man there were some slight alterations with respect to cardiovascular system and liver function tests. In vitro, with high concentrations of CN 3123 there was a weak, unspecific spasmolytic effect on the isolated ureter and an increase in the refractory period of the guinea pig atrium. There were no hints that the side effects seen with separate administration of high or very high doses of sulfamoxole or trimethoprim were increased or poteniated by their simultaneous administration. Slight side effects in animals were only observed with doses exceeding the tenfold of the doses for therapeutic use in men. Therefore, the therapeutic range of CN 3123 seems to be more than adequate.
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PMID:[Pharmacological investigations with the combination sulfamoxole/trimethoprim, a new broadspectrum chemotherapeutic agent (author's transl)]. 94 23

The reabsorption and excretion of sodium, chloride, potassium and water were investigated subsequent to loading with saline solution before and after unilateral hydronephrosis with partial obstruction to flow had been induced in 23 dogs by ligation of the ureter over an indwelling catheter. In the experimental kidney the increase in the total excretion of sodium and chloride and of water in per cent of GFR and the decrease in the reabsorption of sodium, chloride and potassium in per cent of the filtered loads were statistically significant. The glomerulotubular balance was altered statistically probably significantly, but the relation between the capacities for reabsorption of sodium and glucose was maintained. The renal pelvic dilatation was measured and plotted against the degree of renal functional impairment. A statistically significant inverse correlation was noted between renal pelvic volume and reabsorption of sodium and of chloride in per cent of the filtered loads. The osmolality of the urine was the parameter showing the most marked difference between the hydronephrotic and the contralateral kidney. For sodium and chloride the difference between the two sides in the reabsorbed amount in per cent of the filtered load was correlated probably significantly to the degree of renal pelvic dilatation.
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PMID:Renal function in experimental chronic hydronephrosis. IV. Renal handling of sodium and water. 99 53

The concentration of major urinary solutes was studied in ureteral urine collected at 15- to 30-s intervals at the onset of acute diuresis induced in anesthetized dogs either by high-ceiling diuretics (mainly ethacrynic acid) or by osmotic diuretics. Phosphate/inulin clearance ratios remained unchanged; potassium/inulin clearance ratios rose rapidly. Principal attention is given to the mechanisms underlying a transient rise in urinary sodium and chloride concentrations during the onset of diuresis. When the data are corrected for washout artifacts from the pelvis and ureter, it can be shown that the initial collection periods are associated with a transient increase in free-water production and by the simultaneous secretion of urea from the interstitium into the tubular fluid. The former coincides in time with the rise in urinary chloride concentration and represents an augmentation of water reabsorbed in the collecting duct, which is relatively impermeable to chloride. Both responses are quantitatively consistent with the transition from a hyperosmotic to isosmotic medullary interstitium.
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PMID:Electrolyte excretion and free-water production during onset of acute diuresis. 113 May 34

By ligation of the ureter, causing partial ureteral stenosis, unilateral hydronephrosis was induced in 10 dogs. Renal function studies including creatine clearance and osmolality determination were performed both before and after the ureteral ligation. The renal function analysis after induction of hydronephrosis included pyelovenous and pyelolymphatic reflux studies, with deposition of dextran in the renal pelvis at different intrapelvic pressures. Analysis with respect to sodium, potassium, chloride and dextran in the thoracic duct lymph, peripheral blood and urine from the intact kidney were performed. The results show a reduction of the renal function in hydronephrosis, little transport of dextran via the lymph and blood, and no significant increase in the lymphatic transport of the studied ions on elevation of the intrapelvic pressure.
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PMID:Renal function in experimental chronic hydronephrosis. I. Backflow studies with dextran. 120 83


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