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Proximal Vagina (proximal + vagina)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Post-translational Regulation of Endothelial Nitric Oxide Synthase (eNOS) by Estrogens in the Rat Vagina

THE JOURNAL OF SEXUAL MEDICINE, Issue 5 2010
Biljana Musicki PhD
ABSTRACT Introduction., Estrogens control vaginal blood flow during female sexual arousal mostly through nitric oxide (NO). Although vascular effects of estrogens are attributed to an increase in endothelial NO production, the mechanisms of endothelial NO synthase (eNOS) regulation by estrogens in the vagina are largely unknown. Aims., Our hypothesis was that estrogens regulate eNOS post-translationally in the vagina, providing a mechanism to affect NO bioavailability without changes in eNOS protein expression. Methods., We measured eNOS phosphorylation and eNOS interaction with caveolin-1 and heat shock protein 90 (HSP90) in the distal and proximal vagina of female rats at diestrus, 7 days after ovariectomy and 2 days after replacement of ovariectomized rats with estradiol-17, (15 µg). Main Outcome Measures., Molecular mechanisms of eNOS regulation by estrogen in the rat vagina. Results., We localized phospho-eNOS (Ser-1177) immunohistochemically to the endothelium lining blood vessels and vaginal sinusoids. Estrogen withdrawal decreased phosphorylation of eNOS on its positive regulatory site (Ser-1177) and increased eNOS binding to its negative regulator caveolin-1 (without affecting eNOS/HSP90 interaction), and they were both normalized by estradiol replacement. Protein expressions of phosphorylated Akt (protein kinase B) and extracellular signal-regulated protein kinase 1/2 (ERK1/2) were not affected by estrogen status, suggesting that the effect of estrogens on eNOS (Ser-1177) phosphorylation was not mediated by activated AKT or ERK1/2. eNOS phosphorylation on its negative regulatory site (Ser-114) was increased in the vagina by estrogen withdrawal and normalized by estradiol replacement, implying that the maintenance of low phosphorylation of eNOS on this site by estradiol may limit eNOS interaction with caveolin-1 and preserve the enzyme's activity. Total eNOS, inducible NOS, caveolin-1, and HSP90 protein expressions were not affected by ovariectomy or estradiol replacement in the distal or proximal vagina. Conclusions., These results define novel estrogen signaling mechanisms in the vagina which involve eNOS phosphorylation and eNOS,caveolin-1 interaction. Musicki B, Liu T, Strong TD, Lagoda GA, Bivalacqua TJ, and Burnett AL. Post-translational regulation of endothelial nitric oxide synthase (eNOS) by estrogens in the rat vagina. J Sex Med 2010;7:1768,1777. [source]

The Effect of Ovariectomy on Rat Vaginal Tissue Contractility and Histomorphology

THE JOURNAL OF SEXUAL MEDICINE, Issue 2 2006
F. Fatih Önol MD
ABSTRACT Introduction., Ovarian hormones have an important role in age-related genital arousal disorders; however, our knowledge regarding possible vaginal wall morphology and contractility changes in low-hormonal states is limited. Aims., To investigate morphological and functional alterations in the vaginal tissue in a rat ovariectomy model and to show the differences between proximal and distal vagina. Methods., Six weeks following ovariectomy, vaginal tissues were examined under light and electron microscopy. Circularly cut distal and proximal tissues were studied in the organ bath under isometric tension and compared with age-matched controls. Contractile responses to electrical field stimulation (EFS), phenylephrine, carbachol, and the effects of alpha-1 and alpha-2 blockade on EFS-induced contractility were investigated. Relaxation responses to EFS and vardenafil were investigated in precontracted strips. Main Outcome Measures., Differences between control and ovariectomy groups in terms of vaginal tissue contractility and histomorphological properties. Results., Distal vagina showed different epithelial characteristics and a better-developed muscularis compared with proximal vagina. Ovariectomy caused thinning of the epithelium, severe degeneration in epithelial architecture, and smooth muscle atrophy. Contraction and relaxation responses of distal strips were significantly lower in ovariectomized rats. Contractile responses to neuropharmacological stimulation were insignificant in proximal strips of both groups. EFS-induced contractions in distal strips diminished significantly after alpha-1 and alpha-2 adrenergic blockade. EFS caused frequency-dependent relaxation responses in precontracted distal strips, which were significantly decreased after nitric oxide synthase inhibition. Conclusions., Ovariectomy causes significant alteration in rat vaginal tissue morphology and contractility. Contraction and relaxation responses of distal vagina are significantly greater compared with morphologically distinct proximal vagina. Alpha-1 and alpha-2 receptors are the main mediators of contraction in distal rat vaginal tissue whereas nitric oxide pathway may have at least a partial role in relaxation. Main mediators of the rat vaginal tissue relaxation and the effect of ovariectomy on this regulation are yet to be defined. Önol FF, Ercan F, and Tarcan T. The effect of ovariectomy on rat vaginal tissue contractility and histomorphology. J Sex Med 2006;3:233,241. [source]

Diversion colitis in children with colovaginoplasty

BJU INTERNATIONAL, Issue 9 2001
H.A. Syed
Objective To highlight the occurrence of diversion colitis and its effects in colovaginoplasty. Patients and methods The records of 18 children who had undergone colovaginoplasty were reviewed retrospectively. Nine patients had androgen-insensitivity syndrome and three each had congenital adrenal hyperplasia, vaginal agenesis and Mayer,Rokitansky syndrome. Through an abdominoperineal approach a segment of sigmoid colon was isolated on its vascular pedicle and brought to the perineum in the plane between the urethra and rectum, as a blind pouch or as an interposition between the proximal vagina and the perineum. The mean (range) follow-up was 5 (1.5,8) years. Results There were no major complications during the early follow-up. Three patients developed severe vaginal discharge with bleeding 2,7 years after colovaginoplasty; examination showed erythema, oedema, ulceration and bleeding. Histology confirmed the classic features of diversion colitis in all three patients. One child responded to vaginal irrigation with a solution of short-chain fatty acids, and the other two were treated with steroid enemas and mesalazine after a poor response to short-chain fatty acids. One of these patients has required surgical reduction of an excessively long neovagina. Conclusion Symptomatic diversion colitis can occur after colovaginoplasty. The severity of the symptoms raises concerns about the use of colovaginoplasty in children and alternative techniques of vaginal replacement should be considered in the first instance. [source]