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

1. Ionic currents underlying the action potential were recorded from enzymatically isolated smooth muscle cells of guinea-pig ureter. 2. The action potential recorded from a single cell was similar to that from a multicellular preparation. It showed repetitive spikes on a plateau potential which followed the first spike. Treatment with 10 mM-tetraethylammonium (TEA) increased the amplitude and duration of the plateau phase and abolished the repetitive spikes. 3. Under voltage clamp mode, at least two (maybe three) kinds of outward currents were activated during depolarizing pulses. The main outward current was Ca2+-dependent K+ current (IK(Ca], which was mostly blocked in Ca2+-free solution, or by application of 1 mM-cadmium (Cd2+) or 2 mM-tetraethylammonium (TEA). IK(Ca) was greatly decreased by treatment with 5 mM-caffeine or an addition of 10 mM-EGTA in a pipette solution. 4. In the presence of 1 mM-Cd2+ and 2 mM-TEA, a small transient outward current remained. 4-Aminopyridine (1 mM) suppressed the transient outward current by about 40%. Time- and voltage-dependent delayed rectifier outward currents were small in ureter cells. An inwardly rectifying K+ current was not detected. 5. An application of 1 mM-Cd2+, 5 mM-cobalt (Co2+), 1 mM-lanthanum (La3+) or 0.1 microM-nifedipine completely blocked the action potential. Replacement of 80-90% of extracellular Na+ with Li+ or Tris almost abolished the plateau potential and repetitive spikes but did not change significantly the first spike. 6. In the presence of 30 mM-TEA, the inward current elicited by depolarization was monophasic and lasted for more than 1 s. Application of 1 mM-Cd2+, 1 mM-La3+, 0.1 microM-nifedipine, or 5 mM-Co2+ completely blocked inward current. The replacement (87%) of extracellular Na+ ions with Li+, Tris, sucrose or TEA speeded up the decay of inward current; the inward current decreased by 10-60% at the end of a 500 ms pulse. 7. Even in low-Na+ solution (120 mM-TEA), the inactivation of ICa had a quite slow component (tau = 1 s), in addition to another faster component (tau = 100 ms) at 0 mV. When short depolarizing clamp pulses (50 ms) were repetitively applied at short intervals (50 ms) and with interpulse voltage of -10 or -20 mV to mimic the repetitive spikes on the plateau of the action potential, the decline of peak Ca2+ current during the train of pulses was smaller than the decay of Ca2+ current during a long pulse.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Ionic currents in single smooth muscle cells from the ureter of the guinea-pig. 248 52

The effects of high-K and low-Na solutions on the smooth muscle of the guinea-pig ureter have been examined in both normal tissues, and tissues in which the Na pump had been blocked by exposure to K-free solutions or ouabain (high-Na tissues). Tension recording, membrane potential measurements and ion analysis were used. High-K solutions depolarize normal tissues, leading to action potential generation and phasic contractions followed, at concentrations greater than 20-30 mM, by cessation of action potentials and the development of a biphasic contracture which declines slowly during continuous exposure. The contracture is abolished by Ca-antagonist drugs, procaine and Ca-free solutions. Short exposures of normal tissues to Na-free solutions do not result in tension development. Longer exposures may initiate tension, depending on the Na substitute used. Sucrose causes depolarization of the cells and spike development associated with phasic contractions, superimposed on a small contracture; Li depolarizes the cells but causes no tension generation; Tris hyperpolarizes the cells and a small increase in basal tone may be seen. On exposure to K-free solutions or ouabain, the tissues do not develop significant tone but their response to short application of high-K solutions grows with time. The tissues also develop the ability to contract on short applications of low-Na solutions. The low-Na contractures are resistant to concentrations of Ca antagonists that abolish the K responses of normal tissues, but are abolished in Ca-free solutions. The ability of the tissues to contract in Na-free solutions is accompanied by an increase in intracellular Na and loss of intracellular K. Even after several hours' exposure to ouabain, however, the tissues still contain significant amounts of K and the membrane potential is the same as, or more negative than that in normal tissues. Therefore it appears that another mechanism, apart from the Na pump, can regulate intracellular Na. On continuous exposure to Na-free solutions, the contracture declines rapidly. The decline is associated with a loss of intracellular Na. The Na-free contracture is larger when K rather than Tris is used as the substitute. This difference persists in the presence of a concentration of Mn that abolishes the K contracture of normal tissues but is abolished by high concentrations (10 mM) of procaine.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Evidence for sodium-calcium exchange in the guinea-pig ureter. 632

Nephrostomy catheters offer nonsurgical modes of therapy for some renal stones. Continuous lavage of the stones using hemiacidrin (Renacidin) for struvite stones, THAM-E or acetylcysteine for cystine stones, and bicarbonate solution for uric acid stones may dissolve either entire stones or stone fragments remaining after surgery. Although irrigation is not without potential complications, recent developments in technique have minimized these. Nephrostomy tubes can also be used to transmit stone baskets through steerable catheters to snare stones from the upper collecting system or from the ureter; any stone that can be engaged and withdrawn through the tube tract can be removed; stones larger than those which can be safely extracted through the ureterovesical junction can be so treated. Neither of these procedures requires general anesthesia, the rate of serious morbidity is low, and the required hospital stay is often less than that for surgery; these modes of therapy are therefore valuable for certain patients.
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PMID:Therapy for renal calculi via percutaneous nephrostomy: dissolution and extraction. 702 Feb 7

This study aimed to investigate a biocompatible, biomechanically functional, small-diameter (<6 mm) scaffold for tissue engineering a vascular graft using acellular porcine ureters. Porcine ureters were decellularized and sterilized using sequential treatment with hypotonic Tris buffer, sodium dodecyl sulphate 0.1% w/v (plus proteinase inhibitors), nuclease solution (RNase and DNase), and peracetic acid. The scaffold was compared with fresh ureter according to histology, immunocytochemistry, quantitative determination of alpha-galactosyl (alpha-Gal), and biochemistry. The biomechanical properties of the scaffold were compared with those of fresh ureters and human saphenous vein. The biocompatibility of decellularized ureters was assessed using in vitro contact and extract cytotoxicity tests. The in vivo biocompatibility was investigated using a mouse model. The histioarchitecture of the acellular ureteric scaffolds was preserved with some loss of basement membrane proteins while showing no evidence of cellularity. There was no evidence of residual alpha-Gal epitope present in acellular ureter. The ultimate tensile strength, compliance, and burst pressures of the acellular ureters were not compromised, compared with fresh tissues (p > 0.05), and the results compared favorably with fresh human saphenous vein samples (p > 0.05). The decellularized scaffolds were shown to be biocompatible with porcine smooth muscle and endothelial cells in vitro. One month after subcutaneous implantation in mice, explants were analyzed immunohistochemically using anti-CD3, Factor VIII, F4/80 (macrophage), and alpha-smooth muscle actin antibodies. The fresh tissue controls had a significantly thicker capsule (of inflammatory cells and fibrous tissue) than decellularized implants (p < 0.05). Decellularized explants were infiltrated with a combination of fibroblast-like cells and macrophages, indicating a healthy repair process. This study has demonstrated the potential of acellular porcine ureteric scaffolds in tissue engineering small-diameter living vascular grafts.
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PMID:Tissue engineering small-diameter vascular grafts: preparation of a biocompatible porcine ureteric scaffold. 1895 Feb 73