Estimating human ovarian non-growing follicle number: the application of modern stereology techniques to an old problem.

BACKGROUND Previous published reports on the number of non-growing follicles (NGFs) in the human ovary have employed model-based methods for number estimates. These methods are time-intensive, and require correction factors and assumptions that ultimately limit their accuracy. Here, we describe the modification, application and validation of a modern fractionator/optical disector technique for the estimation of human ovarian NGF number. METHODS Forty-eight pairs of normal human ovaries were collected from women (age 8-51 years) undergoing elective bilateral oophorectomy, organ donation, or from autopsy. After gross pathologic examination, systematic random sampling was utilized to obtain tissue for analysis by the fractionator/optical disector method. The precision of individual NGF counts was determined by calculating the observed coefficient of error (OCE). Intra-observer variability and variation in NGF number between ovaries within a pair were also determined. RESULTS The mean OCE was 16.6% with larger variations observed at lower follicle counts. In recount experiments of the same ovary, NGF number estimates varied by 15-29%, except at very low follicle counts where variation was greater, but absolute differences were small. There was no significant difference in NGF number between ovaries within a pair (Wilcoxon signed rank test, P = 0.81). CONCLUSIONS Modern stereology methods provide an unbiased, efficient method for estimating NGF number in the human ovary. Both ovaries within a pair contain similar numbers of NGFs.

Compensatory paracrine mechanisms that define the urothelial response to injury in partial bladder outlet obstruction.

Diseases and conditions affecting the lower urinary tract are a leading cause of dysfunctional sexual health, incontinence, infection, and kidney failure. The growth, differentiation, and repair of the bladder's epithelial lining are regulated, in part, by fibroblast growth factor (FGF)-7 and -10 via a paracrine cascade originating in the mesenchyme (lamina propria) and targeting the receptor for FGF-7 and -10 within the transitional epithelium (urothelium). The FGF-7 gene is located at the 15q15-q21.1 locus on chromosome 15 and four exons generate a 3.852-kb mRNA. Five duplicated FGF-7 gene sequences that localized to chromosome 9 were predicted not to generate functional protein products, thus validating the use of FGF-7-null mice as an experimental model. Recombinant FGF-7 and -10 induced proliferation of human urothelial cells in vitro and transitional epithelium of wild-type and FGF-7-null mice in vivo. To determine the extent that induction of urothelial cell proliferation during the bladder response to injury is dependent on FGF-7, an animal model of partial bladder outlet obstruction was developed. Unbiased stereology was used to measure the percentage of proliferating urothelial cells between obstructed groups of wild-type and FGF-7-null mice. The stereological analysis indicated that a statistical significant difference did not exist between the two groups, suggesting that FGF-7 is not essential for urothelial cell proliferation in response to partial outlet obstruction. In contrast, a significant increase in FGF-10 expression was observed in the obstructed FGF-7-null group, indicating that the compensatory pathway that functions in this model results in urothelial repair.