Human Lower Urinary Tract Research Articles

Studies on binding sites, contents, and effects of AVP in isolated bladder and urethra from rabbits and humans

The binding sites, contents, and effects of arginine vasopressin (AVP) were studied in isolated bladder and urethral preparations from rabbits and humans. In all tissues, higher levels of AVP-like immunoreactivity (AVP-LI) were detected than those normally found in plasma. Radioligand membrane binding studies using [3H]AVP as the ligand revealed the existence of a single population of binding sites in the rabbit bladder, and displacement experiments indicated that the receptor was of the V1 subtype. By autoradiography, [3H]AVP binding sites in the rabbit bladder were shown to be located on both circularly and longitudinally oriented smooth muscle cells, as well as in the submucosa at the part adjacent to the urothelium. In the rabbit urethra, the binding sites were confined mainly to the circular smooth muscle layer. Neither radioligand membrane binding studies nor autoradiography revealed any specific [3H]AVP binding sites in the human bladder. AVP contracted rabbit bladder and urethral preparations concentration dependently. The contractions were inhibited by the V1-receptor selective antagonist A16 in a noncompetitive manner. However, A16 had no effects on contractions elicited by electrical-field stimulation. In preparations of the human bladder and urethra, AVP in concentrations up to 10(-5) M did not have any contractile effects. These results suggest that in the rabbit and human lower urinary tract, AVP-LI is synthesized locally and/or extracted from the circulation. It is unlikely that AVP is directly involved in the neurotransmission in these tissues, although in the rabbit bladder and urethra a modulatory role cannot be excluded.

The distribution of noradrenergic nerves in the human lower urinary tract.

Noradrenergic nerves have been demonstrated amongst the ganglion cells of the vesical plexus and of the bladder. Trigonal smooth muscle receives a supply of noradrenergic fibres although similar nerves are rarely observed in relation to the smooth muscle of the detrusor. In the male numerous noradrenergic nerves occur in the walls of the bladder neck, prostate, seminal vesicles and vas deferens; nerves of this type are scarce in the smooth muscle coat of the female bladder neck and urethra. The striated muscle of the rhabdosphincter in both sexes receives a scant (but significant) supply of noradrenergic nerve fibres.

Patterns of Schistosoma haematobium egg distribution in the human lower urinary tract. I. Noncancerous lower urinary tracts.

Schistosoma haematobium egg burdens (eggs/g of tissue) of 17 anatomic segments of lower urinary tracts from 32 unselected Egyptian autopsies have been determined by tissue digestion and replicate counts of aliquots of the digestate. There were three anatomic patterns of egg distribution in these lower urinary tracts: apical, basal and diffuse. Regression of egg burdens of each of the anatomic segments as the dependent variable against egg burdens of the entire lower urinary burden yielded a good fit for 15 of 17 of these segments. Statistical analyses revealed that many of these equations for discrete anatomic segments can be combined, generally giving one equation for anatomic regions which are in continuity, indicating that the female worm lives and oviposits in specified venous plexes. These equations also suggest that there are differences in the rates, duration and onset of egg accumulation which may be responsible for schistosomal obstructive uropathy as a cause of death in fairly young individuals.

Patterns of Schistosoma Haematobium Egg Distribution in the Human Lower Urinary Tract

In a series of 32 unselected consecutive autopsies of Egyptian male adults, we found a significant prevalence of schistosomal obstructive uropathy (SOU) and of precursor lesions of stenosis, fibrosis and induration of the ureters (62.5%). Lower urinary tracts with obstructive uropathy had a significantly higher total egg burden (TEB) than did lower urinary tracts with any other type of gross lesion (i.e., benign prostatic hypertrophy, other urethral outlet obstruction, or SOU precursor lesions). In turn, lower urinary tracts with any type of gross change had higher egg burdens than did tracts which appeared grossly normal. Lower urinary tracts with any type of gross lesion had significantly larger seminal vesicles than did tracts which were grossly normal. Moreover, relative weight of seminal vesicles could be correlated with the S. haematobium egg burdens in the seminal vesicles. In a series of lower urinary tracts taken from unselected consecutive American autopsies, seminal vesicle weight could be correlated with increase in prostatic weight in those tracts with prostatic hypertrophy; the same correlation could not be found in tracts without prostatic hypertrophy. Thus, seminal vesicle hypertrophy appears to correlate with obstructive uropathy in general, not solely obstructive uropathy of schistosomal origin. Digital evaluation of seminal vesicle size may be useful in the clinical evaluation of such patients.

Patterns of Schistosoma haematobium egg distribution in the human lower urinary tract. III. Cancerous lower urinary tracts.

The distribution of S. haematobium eggs in urinary bladders containing tumors and removed at surgery has been studied; the majority of these tumors are well differentiated squamous cell carcinomas. The same three anatomic patterns of egg accumulation described in part I of this series (noncancerous lower urinary tracts) were found in these cancerous bladders, but, in addition, most of the tumors were surrounded by a collar of heavy S. haematobium egg deposition. The egg burdens in these collars were, on the average, twice the average egg burden in the remainder of the urinary bladder. These collars do not seem to be artifacts created by growth of the tumor and subsequent displacement of the adjacent normal tissue, creating a region of heavy egg concentrations; rather, these heavy S. haematobium egg concentrations seem to act as promoters of urothelial carcinogenesis.

Enzyme Histochemistry of Normal and Neoplastic Transitional Epithelium

The authors utilized the technic of plastic embedding with enzyme histochemistry for the evaluation of enzymatic expression by epithelium of the lower urinary tract in humans. Alpha-naphthyl acetate esterase and acid phosphatase generally were expressed by normal and neoplastic urothelium. Expression of 5'-nucleotidase and ATPase was more restricted. Alkaline phosphatase, prominent in the transitional cells of lower mammalian species, generally was not present in human urothelium. Enzyme histochemistry has not been applied generally to the study of disease of the lower urinary tract, but this study suggests it may be of value in understanding the biology of this tissue and be of potential use in histopathologic diagnosis of diseases of this region.

Enzyme Histochemistry of Normal and Neoplastic Transitional Epithelium

The authors utilized the technic of plastic embedding with enzyme histochemistry for the evaluation of enzymatic expression by epithelium of the lower urinary tract in humans. Alpha-naphthyl acetate esterase and acid phosphatase generally were expressed by normal and neoplastic urothelium. Expression of 5'-nucleotidase and ATPase was more restricted. Alkaline phosphatase, prominent in the transitional cells of lower mammalian species, generally was not present in human urothelium. Enzyme histochemistry has not been applied generally to the study of disease of the lower urinary tract, but this study suggests it may be of value in understanding the biology of this tissue and be of potential use in histopathologic diagnosis of diseases of this region.

Tethered cord syndrome.

The neurologic dysfunction with Tethered cord syndrome (TCS) can be attributed to lumbosacral cord lesions and is reversible if cord-untethering surgery is done at an appropriate time. This chapter seeks to increase urologists’ understanding of TCS and the importance of early diagnosis and treatment in patients with associated urinary incontinence. Patients with TCS usually show hypoactive tendon reflexes in the lower limbs, because the lesions are located in the gray matter and the reflex arcs are inactivated. Storage and emptying are the two fundamental functions in the human lower urinary tract. These are voluntarily controlled by the cerebral centers and by reflex coordination of the spinal cord centers through the parasympathetic and sympathetic systems, which regulate bladder and sphincter contraction. The baseline bladder function of patients who develop TCS is often abnormal, and a significant number of patients who do not respond to untethering surgery will have residual neurogenic bladder dysfunction.

Influence of the adrenergic nervous system on the lower urinary tract and its clinical implications.

The morphology of the adrenergic nervous systems as well as adrenoceptor functions of the human lower urinary tract are outlined and compared to some animal studies. Special emphasis is given to the altered adrenergic innervation and adrenoceptor function after parasympathetic decentralization. Pharmacological treatment affecting adrenoceptors is described in different disturbances of lower urinary tract function and some evidence for adrenergic mechanisms working in intravaginal electrical stimulation is presented. The importance of the sympathetic nervous system for the normal function of the human lower urinary tract is still unclear. Nevertheless, clinical data obtained by treatment with agents influencing this system indicate that the contractory alpha-adrenoceptors of the human urethra can be stimulated or blocked pharmacologically producing significant changes in intraurethral pressure. On the other hand, the relaxatory effect on the human detrusor obtained by stimulation of the beta-adrenoceptors seems to be negligible.

Effects of prostaglandins on the isolated human bladder and urethra.

The effects of prostaglandins F2 alpha (PGF2 alpha), E1 (PGE1) and E2 (PGE2) on the human lower urinary tract were studied in vitro in preparations obtained from patients undergoing total cystourethrectomy because of bladder malignancy. Tissue specimens were taken from different parts of the urethra, the urethrovesical junction, and the bladder. From these specimens, smooth muscle preparations were dissected and mounted in organ baths, that were filled with Krebs solution (37 degrees C) and bubbled with carbogen. Isometric tension was recorded. Preparations from the bladder and all parts of the urethra were contracted by PGF2 alpha. This effect was not affected by tetrodotoxin, phenoxybenzamine, or atropine; isoprenaline relaxed the PGF2 alpha induced contractions. PGE1 and PGE1 both contracted strips from the bladder. However, urethral preparations contracted by PGF2 alpha or noradrenaline were relaxed by these agents. This relaxing effect was at least as pronounced as that produced by isoprenaline; it was not affected by propranolol.