Investigative urology最新文献

Renal hypoplasia and dysplasia may be primary malformations linked to a panureteric bud deformity or result from damage to the developing nephrons caused by abnormal urodynamic pressures, Kidneys with misplaced ureteric orifices were graded, according to histologic criteria, on the hypodysplasia scale. With lateral ectopy of the ureteric orifices with and without congenital urethral obstruction, the grades correlated with specific orifice positions. The grades of kidneys with caudal ectopy of the ureters indicated a more general correlation. Dysgenesis of the bud and nephrogenic mesenchyme may account for the renal hypodysplasia when the ureteric orifice is found to be ectopic.

In order to assess the relative effects of abnormal ureteric orifice position and abnormal urodynamics on the morphogenesis of hypoplasia and dysplasia in kidneys obtained from infants, we devised a method of quantifying the renal structures. The method was based on radial glomerular counts which ranged from zero to normal (seven to nine), a score for dysplastic structures, and the ratio of normal to abnormal tissues present. These three values, when plotted against each other, correlated closely. The glomerular count, with occasional minor adjustment for inconsistencies, was the best parameter of hypodysplasia. Severe to moderate grades of hypodysplasias fell in the low and middle ranges and hypoplasia through to normal in the highest range. By grading kidneys in this way, we were able to compare the effects of ureteral ectopy and abnormal urinary dynamics on the developing kidney.

Effects of various osmotic solutions on membrane properties of smooth muscle cells of the guinea pig ureter were investigated using the microelectrode and double sucrose gap methods. In Krebs solution, the mean membrane potential was -53 mV, chronaxie was 104 msec, length constant of the tissue was 1.03 mm, time constant of the membrane was 65.8 msec, and conduction velocity of excitation was 19.2 mm per sec. Hyperosmotic solution (1.5, 2.0, or 2.5 times the normal osmolarity) depolarized the membrane, generated the spike activity, reduced the length constant of the tissue, increased the time constant of the membrane, prolonged the chronaxie, and reduced the conduction velocity. Hyposmotic solutions (0.85 and 0.67 times the normal osmolarity) produced opposite changes on the passive and active characteristics of the membrane compared to findings in hyperosmotic solution except that the time constant of the membrane was increased in both hyper- and hyposmolar solutions. Increase in the time constant of the membrane and reduced length constant of the tissue in hyperosmotic solution can be explained by an increase in the internal resistance, including the cell to cell junctional resistance and shrinkage of the cell diameter (from 6.2 to 3.0 micrometer).

The net transport of [3H]-inulin into the fluids of the hamster seminiferous and caput, corpus, and cauda epididymal tubules was examined in both intact animals and those vasectomized 10 months previously. Mean isotope concentrations in reproductive tract tubule fluids did not exceeded 10 per cent of blood plasma isotope concentrations during the experiment. There were no significant differences in net transport of [3H]-inulin into any of the tubule fluids sampled. Ten months after vasectomy, the seminiferous tubule, and all regions of the epididymal tubule retain the capacity to exclude [3H]-insulin. Thus in the hamster 10 months after vasectomy, the blood testis and blood epididymal barriers to inulin are intact.

We studied the effect of sterile ureteral reflux on intact and diverted upper urinary tracts. Five dogs underwent transvesical left ureteral meatotomy and anastomosis of the right ureter to a refluxing ileal conduit. Several normal nonrefluxing renal units were also studied. At 6 months, renal function studies were not significantly different among control, ilealureteral, and vesicoureteral refluxing renal units. No radiographic or histopathologic abnormalities were observed in experimental renal units. Sterile intestinalureteral and vesicoureteral reflux do not seem to cause functional or morphologic renal damage.

We developed an improved method for continuous parenteral infusion of rats with minimal animals restraint. This method is reliable, relatively inexpensive, and imposes less stress upon the animal than other methods of infusion previously described.