Molecular biological researches of the lower urinary tract function

Adrenergic alpha1 and beta receptors are present in the target organs of sympathetic nerve and they participate in the signal transduction mechanism of the lower urinary tract. Adrenergic alpha1 receptors are present in urethral and prostatic smooth muscles, and contract these muscles. Among these receptor subtypes, the alpha1-A receptor has the most important role, and mRNA expression of the corresponding alpha1-a subtype is predominant. In the human urinary bladder detrusor smooth muscle, the expression of adrenergic beta3 receptor subtype mRNA is predominant, and relaxation of detrusor smooth muscle is mediated mainly via beta3 receptor. Afferent nerve with lower threshold can easily transmit bladder sensation and takes an important role in the pathophysiology of urge urinary incontinence. Successful molecular cloning of vanilloid receptors, which are present in these afferent nerves, revealed that vanilloid receptors are ion-channels, sensitive for heat and pH, and termed VR1 and VRL1. Among purinergic receptors, ion channel type P2X3 receptor is found in afferent nerve fibers and plays some roles in the signal transduction of bladder sensation. In the near future, agonist for the adrenergic beta3 receptor and selective antagonists for VR1, VRL1, or P2X3 will possibly become drugs for pollakisuria and urge urinary incontinence.     

Comparison of effects of Y-27632 and Isoproterenol on release of cytokines from human peripheral T cells

Y-27632 selectively inhibits Rho-associated protein kinases (ROCKs), an effector for RhoA. The RhoA system is involved in T cell activation. Y-27632 mimicked effects of beta agonists on human cells. We examined the effects of both Y-27632 and Isoproterenol (Iso) on the release of T helper type 1 (Th-1) cytokines (interleukin (IL)-2 and interferon (IFN)-gamma) and Th-2 cytokines (IL-4 and IL-5) from activated human T cells. Peripheral T cells obtained from seven healthy volunteers were incubated in the presence of Y-27632 (0.1-10 micro M) for 30 min, and stimulated with 50 micro g/ml of Concanavalin A (Con A) for 24 h. Concomitantly, after an incubation with medium alone, cells were stimulated with Con A in the presence of Iso (0.1-10 micro M). The concentration of these cytokines in supernatants was measured by ELISA. Both Y-27632 and Iso suppressed release of Th-1 cytokines, decreased release of Th-2 cytokines weakly, and reduced ratio of Th-1/Th-2 cytokine release from Con A-activated T cells. These inhibitory effects of Y-27632 closely resembled those of Iso at each concentration tested. Y-27632 mimicked effects of Iso on secretion of Th-1 and Th-2 cytokines from human peripheral T cells activated with Con A. It is suggested that the RhoA/ROCK system plays an important role in the release of Th-1 cytokines and is partially involved in the release of Th-2 cytokines from human T cells activated through T cell receptor (TCR).     

Pharmacological effects of darifenacin on human isolated urinary bladder

Darifenacin [(S)-2--2,2-diphenylacetamide] is a novel antimuscarinic drug currently undergoing phase III trials for the treatment of overactive bladder. We investigated the functional antagonist potency of darifenacin, and the antimuscarinic drugs propiverine, oxybutynin and atropine, on human detrusor smooth muscle. Urinary bladder specimens were obtained from 20 patients who underwent total cystectomy for malignant bladder tumor. Using an organ-bath technique, the effects of the compounds on carbachol-, KCl-, CaCl(2)- or electrical field stimulation (EFS)-induced contractions of the tissues were evaluated. The order of antagonist potency (pA(2 )values) at the muscarinic M(3) receptors was: darifenacin (9.34) > atropine (9.26) > oxybutynin (7.74) > propiverine (7.68). Darifenacin and atropine, at concentrations up to 10(-6) mol/l, did not inhibit the KCl- and CaCl(2)-induced contractions (concentrations 80 and 5 mmol/l, respectively), while propiverine and oxybutynin (10(-5) mol/l) significantly inhibited these contractions. Pretreatment with darifenacin (10(-9)-10(-6) mol/l), propiverine (10(-8)- 10(-5) mol/l), oxybutynin (10(-8)-10(-5) mol/l) and atropine (10(-9)-10(-6) mol/l) significantly inhibited maximum EFS-induced contractions. Darifenacin inhibited contractions of human detrusor smooth muscle only through its antimuscarinic action, while propiverine and oxybutynin had both antimuscarinic and Ca(2+) channel antagonist actions. These findings indicate that darifenacin is a potent antagonist at the M(3) receptor and support its use as a treatment for overactive bladder.     

Usefulness of soluble dietary fiber for the treatment of diarrhea during enteral nutrition in elderly patients

OBJECTIVES: We investigated the clinical usefulness of soluble dietary fiber (SDF) for the treatment of diarrhea during enteral nutrition in elderly patients. METHODS: This study included 10 men and 10 women (mean age +/- standard deviation: 79.3 +/- 5.1 y) who had diarrhea during long-term nutrition management. When administering SDF, the initial dose was 7 g and thereafter gradually increased at 1-wk intervals. After 4 wk, the administration was discontinued for 2 wk to confirm the effects of SDF. RESULTS: After the administration of SDF, serum diamine oxidase activity significantly increased (P < 0.001): The water content of the feces decreased significantly after the administration of fiber (P < 0.01). The frequency of daily bowel movements also decreased significantly (P < 0.05). Simultaneously, the fecal features improved. Concerning intestinal flora, there were no significant changes in the total number of bacteria or the number of anaerobic bacteria. The fecal pH decreased significantly 4 wk after the administration of fiber (P < 0.05). The total level of short-chain fatty acids increased significantly 4 wk after the administration of fiber (P < 0.05). There were no significant changes in the various nutritional indices. CONCLUSIONS: The administration of SDF is useful for controlling spontaneous, favorable bowel movement by improving symptoms of small intestinal mucosal atrophy and normalizing the intestinal flora.     

Pathological effects on mice by gambierol, possibly one of the ciguatera toxins

Gambierol was isolated from Gambierdiscus toxicus, which causes ciguatera fish poisoning. The acute toxicological effects induced in mice by synthesized gambierol were studied. The lethal doses were about 80 μg/kg by i.p. and i.v., and 150 μg/kg by p.o. The main injury by this toxin was observed in the lung, and secondary in the heart, resulting in systemic congestion. Another toxic effect was seen in the stomach, inducing hypersecretion and ulceration. With survival from the severe stage during the initial 3 h, recovery was favorable, especially after 4 days. Additional effects were not evident during 1-week post-administration observation.     

Radiation-induced apoptosis is independent of caspase-8 but dependent on cytochrome c and the caspase-9 cascade in human leukemia HL60 cells

We investigated the role of the caspase activation cascade in apoptosis induced by ionizing radiation or hydrogen peroxide (H(2)O(2)) in human leukemia HL60 cells. Electron paramagnetic resonance (EPR) spectra revealed that hydroxyl and hydrogen radicals were generated in the culture medium after exposure to radiation or H(2)O(2). Initial accumulation of DNA fragments at 2 h after exposure was delayed in irradiated cells compared with H(2)O(2)-treated cells, although formation of abasic sites immediately after exposure was significantly higher in irradiated cells and similar quantities of hydroxyl radicals were produced under both conditions. Activity assay of caspases revealed that caspase-3, -8 and -9 were activated 2 h after exposure to H(2)O(2), whereas in irradiated cells caspase-3 and -9 activation occurred 4 h after exposure but increased caspase-8 activation was not observed. Release of cytochrome c into cytosol was seen at 2 h after radiation and H(2)O(2) treatment. Radiation did not affect proapoptotic proteins (Bax and Bid), whereas H (2)O(2) increased accumulation of Bax in the mitochondrial membrane 2 h to 6 h after treatment, independently of the truncation of Bid by activated caspase-8. Moreover, treatment with the caspase-8 inhibitor Z-IETD-FMK increased cell survival and prevented accumulation of DNA fragments in H(2)O(2)-treated cells, but not in irradiated cells. These results suggest that, unlike the caspase cascade of H(2)O(2)-induced apoptosis, cytochrome c and caspase-9 are important for the intrinsic pathway of radiation-induced apoptosis, independent of caspase-8.     

Validation of an experimental strategy for studying surface-exposed proteins involved in porcine sperm-oviduct contact interactions

Previous experiments have shown that boar sperm survival in vitro is enhanced when co-incubated with a solubilised protein extract of porcine oviducal apical plasma membrane proteins. Here, we examine the hypothesis that the effects are mediated by direct oviduct-sperm contact and use in situ biotinylation of the oviducal epithelial surface to trace the surface-exposed biotinylated proteins through purification and solubilisation steps. We have also examined the effectiveness of mechanical scraping as a method of recovering oviducal epithelial proteins. We show that a subset of proteins originally exposed at the oviducal surface eventually bind to spermatozoa during incubation in vitro, but also show that a different protein subset is implicated if the sperm incubation is performed with proteins that had been biotinylated after (ex situ) extraction from the oviduct. Apical plasma membrane fractions biotinylated after purification contained many more biotinylated protein bands than preparations labelled before purification and multiple protein bands were eventually found to associate with spermatozoa. Although the evidence presented here supports the hypothesis that protein(s) anchored to the oviducal epithelium bind populations of spermatozoa directly and may have a role in the enhancement of sperm viability, it also shows that the choice of investigative technique exerts a major influence on experimental outcomes.     

A novel relation of fatty acid with age-related macular degeneration

To evaluate the relation between fatty acids and age-related macular degeneration (ARMD), the fatty acid fractions within the red blood cell (RBC) membrane and plasma of 11 ARMD patients and 10 healthy individuals (controls) were determined and compared. RBC arachidonic acid (AA) and docosahexaenoic acid (DHA) exhibited significantly higher values in the ARMD patients than in the controls. RBC levels of palmitic, palmitoleic, oleic and linoleic acids, however, showed significantly higher values in the controls than in the ARMD patients. No significant variations were observed between the two groups in terms of plasma levels of AA, DHA, palmitic, palmitoleic, oleic and linoleic acids. Our findings indicate that polyunsaturated fatty acids, vulnerable to free radicals and reactive oxygen species, and easily peroxidized, may be related to ARMD induction.