Biochemical isolation and purification of ovulation-inducing factor (OIF) in seminal plasma of llamas

BACKGROUND

The objective of the present study was to isolate and purify the protein fraction(s) of llama seminal plasma responsible for the ovulation-inducing effect of the ejaculate.

METHODS

Semen collected from male llamas by artificial vagina was centrifuged and the seminal plasma was harvested and stored frozen. Seminal plasma was thawed and loaded onto a Type 1 macro-prep ceramic hydroxylapatite column and elution was carried out using a lineal gradient with 350 mM sodium phosphate. Three protein fractions were identified clearly (Fractions A, B, and C), where a prominent protein band with a mass of 14 kDa was identified in Fraction C. Fraction C was loaded into a sephacryl gel filtration column for further purification using fast protein liquid chromatography (FPLC). Isocratic elution resulted in 2 distinct protein fractions (Fractions C1 and C2). An in vivo bioassay (n=10 to 11 llamas per group) was used to determine the ovarian effect of each fraction involving treatment with saline (negative control), whole seminal plasma (positive control), or seminal plasma Fractions A, B or C2. Ultrasonography was done to detect ovulation and CL formation, and blood samples were taken to measure plasma progesterone and LH concentrations.

RESULTS

Ovulation and CL formation was detected in 0/10, 10/11, 0/10, 2/11, and 10/11 llamas treated with saline, whole seminal plasma, Fractions A, B and C2 respectively (P<0.001). A surge in circulating concentrations of LH was detected within 2 hours only in llamas treated with either whole seminal plasma or Fraction C2. Plasma progesterone concentration and CL diameter profiles were greatest (P<0.05) in llamas treated with Fraction C2.

CONCLUSION

Ovulation-inducing factor was isolated from llama seminal plasma as a 14 kDa protein molecule that elicits a preovulatory LH surge followed by ovulation and CL formation in llamas, suggesting an endocrine effect at the level of the hypothalamus (release of GnRH) or the pituitary (gonadotrophs).

Digit ratios by computer-assisted analysis confirm lack of anatomical evidence of prenatal androgen exposure in clinical phenotypes of polycystic ovary syndrome

BACKGROUND

We recently showed that women with four clinical phenotypes of polycystic ovary syndrome (PCOS) do not demonstrate anatomical evidence of elevated prenatal androgen exposure as judged by a lower ratio of the index (2D) to ring (4D) finger. However, those findings conflicted with a previous study where women with PCOS had lower right hand 2D:4D compared to healthy female controls. Both these studies used Vernier calipers to measure finger lengths--a method recently shown to be less reliable at obtaining finger length measurements than computer-assisted analysis.

METHODS

Ninety-six women diagnosed with PCOS according to the 2003 Rotterdam criteria had their finger lengths measured with computer-assisted analysis. Participants were categorized into four recognized phenotypes of PCOS and their 2D:4D compared to healthy female controls (n = 48) and men (n = 50).

RESULTS

Digit ratios assessed by computer-assisted analysis in women with PCOS did not differ from female controls, but were significantly lower in men. When subjects were stratified by PCOS phenotype, 2D:4D did not differ among phenotypes or when compared to female controls.

CONCLUSION

Computer-assisted measurements validated that digit ratios of women with PCOS do not show anatomical evidence of increased prenatal androgen exposure.

Development of morphologically dominant follicles is associated with fewer metabolic disturbances in amenorrheic women with polycystic ovary syndrome: a pilot study

OBJECTIVES

To determine if amenorrheic women with polycystic ovary syndrome (PCOS) demonstrate ultrasonographically detectable changes in follicle population.

METHODS

Sixteen women with PCOS reporting the absence of menses for more than 3 months were enrolled in the study. Subjects had a physical examination, fasting blood tests and two transvaginal ultrasound scans spaced 1 month apart. In cases where evidence of a morphologically dominant follicle (≥ 10 mm in diameter) occurred, subsequent ultrasound scans were performed to determine the fate of the dominant follicle. Differences in total follicle population, maximum follicle diameter and clinical, hormonal and metabolic features were determined.

RESULTS

Forty-four percent of subjects showed changes in follicle population of 6-10 follicles and 37% showed changes in follicle population of > 10. Maximum follicle diameters ranged between 5.4 and 33.0 mm. Four subjects demonstrated follicle diameters ≥ 10 mm. Of those who developed dominant follicles, two subjects ovulated, one subject developed a persistent anovulatory follicle and the dominant follicle regressed in the remaining subject. Diagnostic criteria for PCOS were similar among women that did or did not develop dominant follicles (menstrual cycle length, P = 0.880; hirsutism score, P = 0.809; free androgen index, P = 0.991; total follicle count, P = 0.199). However, lower glycosylated hemoglobin (P = 0.047) and insulin levels (P = 0.049) and better insulin sensitivity (P = 0.048) were noted in women who attained dominant follicles.

CONCLUSION

Amenorrheic women with PCOS demonstrate changes in follicle population that are consistent with active follicle growth and regression despite prolonged periods of anovulation. Morphologic selection occurs in amenorrheic women and attainment of dominant follicles is associated with improved metabolic status.

Grid analysis improves reliability in follicle counts made by ultrasonography in women with polycystic ovary syndrome

Poor reliability has been reported when counting the total number of follicles in polycystic ovaries using conventional two-dimensional (2-D) ultrasound viewing methods. In the current study, we report good reliability in follicle counts when observers imposed a programmable grid system over the viewing window. Four observers estimated total follicle counts in 45 ovarian ultrasound scans by compartmentalizing the ovary into 9 to 12 grid sections and performing focused follicle counts per section. The mean number of follicles counted per ovary was 44.6 +/- 2.3. The level of inter-observer agreement when making follicle counts was 0.82 and total follicle counts did not differ among observers. The level of intra-observer agreement was 0.93 which further corroborated the utility of this method for making dependable follicle counts. In summary, the ability to obtain reproducible follicle counts will help to establish reliable diagnostic criteria for polycystic ovarian morphology.

Digit ratios do not serve as anatomical evidence of prenatal androgen exposure in clinical phenotypes of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is heterogeneous in its clinical presentation and four major phenotypes have been identified. The precise etiology of PCOS is unknown; however, variable exposure to prenatal androgens may be responsible for the spectrum of endocrine and metabolic disturbances characteristic of this syndrome. Since prenatal testosterone exposure is known to decrease the ratio of the second to fourth finger lengths (2D:4D), we characterized the left and right hand 2D:4D in women with clinical variants of PCOS. We hypothesized that if prenatal androgens were involved in the development of the phenotypic spectrum of PCOS, then lower 2D:4D would be differentially expressed among clinical variants of the syndrome.

METHODS

Digit ratios were determined in 98 women diagnosed with PCOS by the 2003 international consensus guidelines and in 51 women with regular menstrual cycles, no clinical or biochemical signs of hyperandrogenism and normal ovarian morphology. Women with PCOS were categorized into four clinical phenotypes (i.e. Frank, Non-PCO, Ovulatory and Mild) and 2D:4D among groups were compared by Tukey-Kramer multiple comparisons tests.

RESULTS

Left (P = 0.77) and right (P = 0.68) hand 2D:4D were similar among the four clinical phenotypes and no phenotype of PCOS demonstrated a 2D:4D that differed from controls (Left Hand, P = 0.44 and Right Hand, P = 0.75).

CONCLUSIONS

Women with PCOS do not demonstrate finger length patterns that are consistent with increased prenatal androgen exposure. These findings do not preclude a role for prenatal androgens in the development of PCOS; however, low 2D:4D are not a characteristic of PCOS.

Evaluation of the ultrasound image attributes of developing ovarian follicles in the four follicular waves of the interovulatory interval in ewes

Computer-assisted quantitative echotextural analysis was applied to ultrasound images of antral follicles in the follicular waves of an interovulatory interval in sheep. The ewe has three or four waves per cycle. Seven healthy, cyclic Western White Face ewes (Ovis aris) underwent daily, transrectal, ovarian ultrasonography for an interovulatory interval. Follicles in the third wave of the ovulatory interval had a longer static phase than that of those in Waves 1 and 2 (P<0.05). The numeric pixel value for the wall of anovulatory follicles emerging in the third wave of the cycle was significantly higher than that for Waves 1 and 2 at the time of emergence (156.7+/-8.09, 101.6+/-3.72, and 116.5+/-13.93, respectively), and it decreased as follicles in Wave 3 reached maximum follicular diameter (P<0.05). The numeric pixel value of the antrum in the ovulatory follicles decreased as follicular diameter increased to > or =5mm in diameter (P<0.05). The pixel heterogeneity of the follicular antrum in Wave 1 increased from the end of the growth phase to the end of the regression phase for follicles in that wave (P<0.05). The total area for the wall and antrum of the follicles studied were correlated with follicular diameter in all follicular waves (r=0.938, P<0.01 and r=0.941, P<0.01 for the wall and antrum, respectively). Changes in image attributes of the follicular wall and antrum indicate potential morphologic and functional differences among antral follicles emerging at different stages of the interovulatory interval in cyclic ewes.

Ovarian imaging in the mouse using ultrasound biomicroscopy (UBM): a validation study

The mouse is a well accepted model for studies of human reproduction despite little being known about follicle dynamics in this species. Longitudinal studies of mouse folliculogenesis have been hampered by the lack of an appropriate imaging tool. Ultrasound biomicroscopy (UBM) may overcome this obstacle as it confers near-microscopic resolution through the use of high-frequency ultrasound waves. The objective of the present study was to determine whether UBM could be used to count and measure ovarian follicles and corpora lutea (CL) reliably in mice. Ovaries of 25 adult CD-1 mice were imaged using a 55-MHz transducer and then excised and processed for histology. Follicles and CL were counted and measured from digitally stored UBM cine-loops and photographed histological sections. Differences between techniques were assessed by Bland-Altman agreement analyses. Follicle counts yielded by the two techniques varied by only +/-1 follicle when follicles ranged between 300 and 499 microm. Perfect agreement among counts was evident when follicles were >500 microm. The total number of CL was accurately estimated using UBM; however, the number of 350-699 microm CL was underestimated and the number of CL>or=700 microm was overestimated. In conclusion, UBM can be used reliably to count and measure follicles in mice.

Digit ratios (2D:4D) determined by computer-assisted analysis are more reliable than those using physical measurements, photocopies, and printed scans

Prenatal androgens influence the second to fourth digit ratio (2D:4D) of hands with men having lower ratios than women. Numerous methods are used to assess 2D:4D including, physical measurements with calipers, and measurements made from photocopies, scanned images, digital photographs, radiographs, and scaled tubes. Although each method appears relatively reliable, agreement upon a gold standard is necessary to better explore the putative effects of prenatal androgens. Our objective was to assess the level of intra and interobserver reliability when evaluating 2D:4D using four techniques: (1) physical measurements, (2) photocopies, (3) printed scanned images, and (4) computer-assisted image analysis. Physical measurements, photocopies, and printed scanned images were measured with Vernier calipers. Scanned images were also measured with computer-based calipers. Measurements were made in 30 men and 30 women at two different time points, by three experienced observers. Intraclass correlation coefficients were used to assess the level of reliability. Intraobserver reliability was best for computer-assisted (0.957), followed by photocopies (0.939), physical measurements (0.925), and printed scans (0.842; P = 0.015). Interobserver reliability was also greatest for computer-assisted (0.892), followed by photocopies (0.858), physical measurements (0.795), and printed scans (0.761; P = 0.001). Mean 2D:4D from physical measurements were higher than all other techniques (P < 0.0001). Digit ratios determined from computer-assisted, physical measurements, and printed scans were more reliable in men than women (P = 0.009, P = 0.017, and P = 0.012, respectively). In summary, 2D:4D determined from computer-assisted analysis yielded the most accurate and consistent measurements among observers. Investigations of 2D:4D should use computer-assisted measurements over alternate methods whenever possible.

Assessment of ultrasonographic features of polycystic ovaries is associated with modest levels of inter-observer agreement

Background

There is growing acceptance that polycystic ovaries are an important marker of polycystic ovary syndrome (PCOS) despite significant variability when making the ultrasound diagnosis. To better understand the nature of this variability, we proposed to evaluate the level of inter-observer agreement when identifying and quantifying individual ultrasonographic features of polycystic ovaries.

Methods

Digital recordings of transvaginal ultrasound scans performed in thirty women with PCOS were assessed by four observers with training in Radiology or Reproductive Endocrinology. Observers evaluated the scans for: 1) number of follicles ≥ 2 mm per ovary, 2) largest follicle diameter, 3) ovarian volume, 4) follicle distribution pattern and 5) presence of a corpus luteum (CL). Lin's concordance correlation coefficients and kappa statistics for multiple raters were used to assess inter-observer agreement.

Results

Agreement between observers ranged from 0.08 to 0.63 for follicle counts, 0.27 to 0.88 for largest follicle diameter, 0.63 to 0.86 for ovarian volume, 0.51 to 0.76 for follicle distribution pattern and 0.76 to 0.90 for presence of a CL. Overall, reproductive endocrinologists demonstrated better agreement when evaluating ultrasonographic features of polycystic ovaries compared to radiologists (0.71 versus 0.53; p = 0.04).

Conclusion

Inter-observer agreement for assessing ultrasonographic features of polycystic ovaries was moderate to poor. These findings support the need for standardized training modules to characterize polycystic ovarian morphology on ultrasonography.

Significance of concurrent endometrial cancer in women with a preoperative diagnosis of atypical endometrial hyperplasia

OBJECTIVES

Our objectives were (1) to review the rate of concurrent endometrial cancer in patients with a preoperative diagnosis of atypical endometrial hyperplasia (AEH); (2) to determine the proportion of patients with concurrent endometrial cancer who have high-risk disease; and (3) to re-evaluate our surgical management of AEH.

METHODS

We performed a retrospective chart review of all patients who had surgery on the basis of a preoperative diagnosis of atypical endometrial hyperplasia between January 2001 and December 2006. Demographic data, the method of preoperative diagnosis, postoperative grade of tumour, and other postoperative findings were recorded. When applicable, this included cancer stage, lymph node status, and presence of lymphovascular space invasion. In postoperative review, patients were considered to be high risk if they had disease beyond the uterus or a combination of other risk factors.

RESULTS

Of 70 patients, 25 (35.7%) were found to have concurrent endometrial cancer. This was higher than the commonly accepted rate of 25% (P = 0.03). Of the 25 patients upgraded, 4 (16%) had high-risk cancer on final pathologic evaluation.

CONCLUSION

Simple hysterectomy in women with AEH may result in inadequate surgical management. Simple methods are required to identify patients with a preoperative diagnosis of AEH who may harbour significant cancers.

Level set segmentation of bovine corpora lutea in ex situ ovarian ultrasound images

BACKGROUND

The objective of this study was to investigate the viability of level set image segmentation methods for the detection of corpora lutea (corpus luteum, CL) boundaries in ultrasonographic ovarian images. It was hypothesized that bovine CL boundaries could be located within 1-2 mm by a level set image segmentation methodology.

METHODS

Level set methods embed a 2D contour in a 3D surface and evolve that surface over time according to an image-dependent speed function. A speed function suitable for segmentation of CL's in ovarian ultrasound images was developed. An initial contour was manually placed and contour evolution was allowed to proceed until the rate of change of the area was sufficiently small. The method was tested on ovarian ultrasonographic images (n = 8) obtained ex situ. A expert in ovarian ultrasound interpretation delineated CL boundaries manually to serve as a "ground truth". Accuracy of the level set segmentation algorithm was determined by comparing semi-automatically determined contours with ground truth contours using the mean absolute difference (MAD), root mean squared difference (RMSD), Hausdorff distance (HD), sensitivity, and specificity metrics.

RESULTS AND DISCUSSION

The mean MAD was 0.87 mm (sigma = 0.36 mm), RMSD was 1.1 mm (sigma = 0.47 mm), and HD was 3.4 mm (sigma = 2.0 mm) indicating that, on average, boundaries were accurate within 1-2 mm, however, deviations in excess of 3 mm from the ground truth were observed indicating under- or over-expansion of the contour. Mean sensitivity and specificity were 0.814 (sigma = 0.171) and 0.990 (sigma = 0.00786), respectively, indicating that CLs were consistently undersegmented but rarely did the contour interior include pixels that were judged by the human expert not to be part of the CL. It was observed that in localities where gradient magnitudes within the CL were strong due to high contrast speckle, contour expansion stopped too early.

CONCLUSION

The hypothesis that level set segmentation can be accurate to within 1-2 mm on average was supported, although there can be some greater deviation. The method was robust to boundary leakage as evidenced by the high specificity. It was concluded that the technique is promising and that a suitable data set of human ovarian images should be obtained to conduct further studies.

Diagnostic criteria for polycystic ovary syndrome: pitfalls and controversies

It is estimated that as many as 1.4 million Canadian women may be afflicted with polycystic ovary syndrome (PCOS). Although PCOS is heralded as one of the most common endocrine disorders occurring in women, its diagnosis, management, and associated long-term health risks remain controversial. Historically, the combination of androgen excess and anovulation has been considered the hallmark of PCOS. To date, while these symptoms remain the most prevalent among PCOS patients, neither is considered an absolute requisite for the syndrome. Inclusion of ultrasonographic evidence of polycystic ovaries as a diagnostic marker has substantially broadened the phenotypic spectrum of PCOS, yet much debate surrounds the validity of these newly identified milder variants of the syndrome. Difficulty in resolving the spectrum of PCOS stems from the continued use of inconsistent and inaccurate methods of evaluating androgen excess, anovulation, and polycystic ovaries on ultrasound. At present, there is no clear-cut definition of biochemical hyperandrogenemia, particularly since we depend on poor laboratory standards for measuring androgens in women. Clinical signs of hyperandrogenism are ill-defined in women with PCOS, and the diagnosis of both hirsutism and polycystic ovarian morphology remains alarmingly subjective. Lastly, there is an inappropriate tendency to assign ovulatory status solely on the basis of menstrual cycle history or poorly timed endocrine measurements. In this review, we elaborate on these limitations and propose possible resolutions for clinical and research settings. By stimulating awareness of these limitations, we hope to generate a dialogue aimed at solidifying the evaluation of PCOS in Canadian women.

Improving inter-observer variability in the evaluation of ultrasonographic features of polycystic ovaries

BACKGROUND

We recently reported poor inter-observer agreement in identifying and quantifying individual ultrasonographic features of polycystic ovaries. Our objective was to determine the effect of a training workshop on reducing inter-observer variation in the ultrasonographic evaluation of polycystic ovaries.

METHODS

Transvaginal ultrasound recordings from thirty women with polycystic ovary syndrome (PCOS) were evaluated by three radiologists and three reproductive endocrinologists both before and after an ultrasound workshop. The following endpoints were assessed: 1) follicle number per ovary (FNPO), 2) follicle number per single cross-section (FNPS), 3) largest follicle diameter, 4) ovarian volume, 5) follicle distribution pattern and 6) presence of a corpus luteum (CL). Lin's concordance correlation coefficients (rho) and kappa statistics for multiple raters (kappa) were used to assess level of inter-observer agreement (>0.80 good, 0.60 - 0.80 moderate/fair, <0.60 poor).

RESULTS

Following the workshop, inter-observer agreement improved for the evaluation of FNPS (rho = 0.70, delta rho = +0.11), largest follicle diameter (rho = 0.77, delta rho = +0.10), ovarian volume (rho = 0.84, delta rho = +0.12), follicle distribution pattern (kappa = 0.80, delta kappa = +0.21) and presence of a CL (kappa = 0.87, delta kappa = +0.05). No improvement was evident for FNPO (rho = 0.54, delta rho = -0.01). Both radiologists and reproductive endocrinologists demonstrated improvement in scores (p < 0.001).

CONCLUSION

Reliability in evaluating ultrasonographic features of polycystic ovaries can be significantly improved following participation in a training workshop. If ultrasonographic evidence of polycystic ovaries is to be used as an objective measure in the diagnosis of PCOS, then standardized training modules should be implemented to unify the approach to evaluating polycystic ovarian morphology.

Metabolic fuel and clinical implications for female reproduction

Reproduction is a physiologically costly process that consumes significant amounts of energy. The physiological mechanisms controlling energy balance are closely linked to fertility. This close relationship ensures that pregnancy and lactation occur only in favourable conditions with respect to energy. The primary metabolic cue that modulates reproduction is the availability of oxidizable fuel. An organism's metabolic status is transmitted to the brain through metabolic fuel detectors. There are many of these detectors at both the peripheral (e.g., leptin, insulin, ghrelin) and central (e.g., neuropeptide Y, melanocortin, orexins) levels. When oxidizable fuel is scarce, the detectors function to inhibit the release of gonadotropin-releasing hormone and luteinizing hormone, thereby altering steroidogenesis, reproductive cyclicity, and sexual behaviour. Infertility can also result when resources are abundant but food intake fails to compensate for increased energy demands. Examples of these conditions in women include anorexia nervosa and exercise-induced amenorrhea. Infertility associated with obesity appears to be less related to an effect of oxidizable fuel on the hypothalamic-pituitary-ovarian axis. Impaired insulin sensitivity may play a role in the etiology of these conditions, but their specific etiology remains unresolved. Research into the metabolic regulation of reproductive function has implications for elucidating mechanisms of impaired pubertal development, nutritional amenorrhea, and obesity-related infertility. A better understanding of these etiologies has far-reaching implications for the prevention and management of reproductive dysfunction and its associated comorbidities.

Ultrasonographic characteristics of ovulatory follicles and associated endocrine changes in cyclic ewes treated with medroxyprogesterone acetate (MAP)-releasing intravaginal sponges and equine chorionic gonadotropin (eCG)

The aim of this study was to assess the ultrasonographic characteristics of ovulatory follicles in cyclic Western White Face ewes (December) that had received intravaginal sponges containing medroxyprogesterone acetate (MAP; 60 mg) for 12 days, with or without an injection of 500 IU of equine chorionic gonadotropin (eCG) at sponge removal. We hypothesized that quantitative echotextural attributes of the follicles in ewes treated only with MAP would differ from those in MAP/eCG-treated ewes, reflecting the increased antral follicular growth and secretory function under eCG influence. Digital images of ovulatory follicles obtained at 0 and 24 h after MAP sponge removal and at 24 h before ovulation in the eCG-treated (five ewes, 13 follicles) and control (six ewes, 9 follicles) animals, were subjected to computerized analyses. The mean diameter of ovulatory follicles increased (p < 0.001) 24 h after eCG treatment. The mean pixel intensity and heterogeneity of the follicular antrum (p < 0.001), as well as mean pixel intensity of the follicular wall and perifollicular ovarian stroma (p < 0.05), were greater in eCG-treated animals compared with control ewes 24 h after sponge removal and at 24 h before ovulation. Mean serum concentrations of oestradiol-17beta tended to increase (p = 0.06) 24 h after eCG treatment and the eCG-treated ewes exceeded (p < 0.05) control animals in progesterone concentrations from days 9-15 after ovulation. Our results support the hypothesis that large antral follicles in eCG-treated ewes exhibit distinctive echotextural characteristics. Follicular image attributes in eCG-treated ewes appear to be indicative of the changes in follicular morphology and secretory activity caused by the administration of the exogenous gonadotropin, which has both FSH- and LH-like activities.

Evaluation of texture features for analysis of ovarian follicular development

We examined the echotexture in ultrasonographic images of the wall of dominant ovulatory follicles in women during natural menstrual cycles and dominant anovulatory follicles which developed in women using oral contraceptives (OC). Ovarian follicles in women are fluid-filled structures in the ovary that contain oocytes (eggs). Dominant follicles are physiologically selected for preferential development and ovulation. Statistically significant differences between the two classes of follicles were observed for two co-occurrence matrix derived texture features and two edge-frequency based texture features which allowed accurate distinction of healthy and atretic follicles of similar diameters. Trend analysis revealed consistent turning points in time series of texture features between 3 and 4 days prior to ovulation coinciding with the time at which follicles are being biologically "prepared" for ovulation.

Maternal decisions regarding prenatal diagnosis: rational choices or sensible decisions?

The premise underlying prenatal testing is that knowing the health status of the fetus will enable expectant parents to make rational reproductive decisions. Accordingly, rational-choice perspectives have informed both counselling protocols and the majority of investigations into the psychological processes involved in making decisions about testing and selective abortion. However, because conditions inherent in the testing situation may not adhere to the basic assumptions of rational choice models, the use of these models may be inappropriate. The individualistic focus of rational choice models may be too narrow to encompass the social and psychological factors relevant to making a decision about testing. In light of these limitations, we make a case for adopting a contextual framework for conceptualizing decisions regarding the use of prenatal testing.

Ultrasonographic image attributes of non-ovulatory follicles and follicles with different luteal outcomes in gonadotropin-releasing hormone (GnRH)-treated anestrous ewes

Ultrasonographic images are composed of multiple square picture elements called pixels. Quantitative changes in numerical pixel values (echotexture) determined by computer-assisted analysis of digital images reflect discrete changes in the microscopic structure and physiological status of ovarian antral follicles. The objective of the present study was to determine and compare the ultrasonographic attributes of non-ovulatory antral follicles that grew to an ostensibly ovulatory diameter (> or =5mm) and follicles with different luteal outcomes in response to gonadotropin-releasing hormone (GnRH) in anestrous Western White Face ewes (n=34). All animals received GnRH injections (250ng i.v. every 2h for 24h) followed by a bolus injection of 125microg of GnRH i.v. Ovarian images obtained by repeated transrectal ultrasonography were digitized and subjected to computerized analyses to determine the changes in follicular size and echotexture of the follicular antrum and wall. At the beginning of GnRH treatment, follicles that formed inadequate corpora lutea following ovulation (ICL; n=22) had higher (P<0.001) pixel intensity of the central and peripheral antrum compared with non-ovulatory follicles (n=40). Pixel intensity of the central follicular antrum was greater (P<0.01) in follicles that formed ICL compared with follicles that formed normal (full-lifespan) CL post-treatment (NCL; n=20) and mean pixel heterogeneity of the follicular wall was greater (P<0.05) in non-ovulatory follicles compared with follicles that gave rise to NCL. At the time of GnRH bolus injection (i.e., induction of a synchronous LH surge), the mean diameter of non-ovulatory follicles was greater (P<0.01) than that of all ovulating follicles, and pixel heterogeneity of the central follicular antrum was lowest (P<0.05) in non-ovulatory follicles. The mean diameter of luteinized unovulated follicles (n=9) tended to be greater (P<0.10) at 2.5 and 3 days after emergence, and pixel intensity of the follicular wall was lower (P<0.05) compared with non-luteinized follicles (n=8) at 1.5 and 2.5 days after emergence (beginning of the growth from approximately 3mm onwards). In conclusion, ovarian antral follicles with different outcomes after GnRH treatment (in seasonally anestrous ewes) had distinctive ultrasonographic characteristics.

Enhancing ultrasound texture differences for developing an in vivo 'virtual histology' approach to bovine ovarian imaging

A ‘virtual histology’ can be thought of as the ‘staining’ of a digital ultrasound image via image processing techniques in order to enhance the visualisation of differences in the echotexture of different types of tissues. Several candidate image-processing algorithms for virtual histology using ultrasound images of the bovine ovary were studied. The candidate algorithms were evaluated qualitatively for the ability to enhance the visual differences in intra-ovarian structures and quantitatively, using standard texture description features, for the ability to increase statistical differences in the echotexture of different ovarian tissues. Certain algorithms were found to create textures that were representative of ovarian micro-anatomical structures that one would observe in actual histology. Quantitative analysis using standard texture description features showed that our algorithms increased the statistical differences in the echotexture of stroma regions and corpus luteum regions. This work represents a first step toward both a general algorithm for the virtual histology of ultrasound images and understanding dynamic changes in form and function of the ovary at the microscopic level in a safe, repeatable and non-invasive way.

Computer assisted image analyses of corpora lutea in relation to peripheral concentrations of progesterone: A comparison between breeds of sheep with different ovulation rates

Transrectal ovarian ultrasonography is a non-invasive technique that permits the real-time serial visualization of ovarian structures. Previous studies have reported correlations between serum progesterone concentrations and physical characteristics of the corpus luteum (CL) in different species. The aim of the present study was to investigate whether or not there were correlations between ultrasound image attributes of the CL and changing progesterone concentrations over time, in prolific and non-prolific ewes. Ultrasonographic images of CL were taken, once daily, from 12 Western White Face ewes and 7 Finn ewes for the duration of one luteal phase. Blood samples were collected daily prior to each scanning session and assayed to determine mean serum concentrations of progesterone. Analysis of ultrasound images was performed using a series of custom-developed computer algorithms optimized for ultrasonography on a computer graphics workstation. Both total luteal area and mean pixel values were correlated with the pattern of serum concentrations of progesterone from days 3 to 15 after ovulation in Western White Face ewes and from days 3 to 14 in Finn ewes. There was no significant correlation between progesterone concentrations and spot pixel heterogeneity for either Western White Face ewes or Finn ewes. We concluded that pixel heterogeneity is a poor indicator of progesterone secretory ability of the CL when compared to mean pixel values. However, luteal area and mean spot pixel values are better but not strong indicators of the functional status of the CL in cyclic ewes.

Bovine model of reproductive aging: Response to ovarian synchronization and superstimulation

The responsiveness of the hypothalamo-pituitary axis to steroid treatments for ovarian synchronization and the ovarian superstimulatory response to exogenous FSH was compared in 13-14 year old cows and their 1-4 year old young daughters. We tested the hypotheses that aging in cattle is associated with: (1) decreased follicular wave synchrony after estradiol and progesterone treatment; (2) delayed LH surge and ovulation in response to exogenous preovulatory estradiol treatment; (3) reduced superstimulatory response to exogenous FSH. Higher plasma FSH concentrations (P<0.01), and a tendency (P=0.07) for fewer 4-5 mm follicles at wave emergence were observed in old cows (n=10) than in young cows (n=9). The suppressive effect of estradiol/progesterone treatment on FSH was similar between old and young cows. Although the preovulatory LH surge in response to estradiol treatment was delayed in old than young cows (P=0.01), detected ovulation times were not different. No difference in ovarian superstimulatory response was detected between age groups, but old cows (n=8) tended (P=0.10) to have fewer large follicles (>or=9 mm) 12 h after last FSH treatment than in young cows (n=7). We concluded that pituitary and ovarian responsiveness to estradiol/progesterone synchronization treatment was similar between old and young cows, but aging was associated with a delayed preovulatory LH surge subsequent to estradiol treatment. Old cows tended to have fewer large follicles after superstimulatory treatment than young cows.

Effects of oral contraceptives administered at defined stages of ovarian follicular development

OBJECTIVE

To elucidate the effects of initiating oral contraceptives (OC) at defined stages of ovarian follicle development.

DESIGN

Prospective longitudinal study.

SETTING

Healthy volunteers in an academic research environment.

PATIENT(S)

Forty-five healthy women between the ages of 18 and 35 years, randomized to initiate OC when a follicle diameter of 10, 14, or 18 mm was first detected.

INTERVENTION(S)

The OC administration at defined stages of dominant follicle development.

MAIN OUTCOME MEASURE(S)

Fates of all dominant follicles and serum concentrations of E(2)-17beta, LH, and P before and after initiating OC.

RESULT(S)

No ovulations (0/16) were observed when OC use was initiated at a follicle diameter of 10 mm, 4/14 (29%) follicles ovulated when OC were initiated at 14 mm, and 14/15 (93%) ovulated when OC were initiated at 18 mm. When ovulation did not occur, follicles regressed or became anovulatory cysts. Peak LH and E(2) levels were lowest in the 10-mm group, moderate in the 14-mm group, and greatest in the 18-mm group. Peak endocrine levels in all treatment groups were lower than the historic reference group.

CONCLUSION(S)

Follicular development, ovulation, and endocrine concentrations were not suppressed effectively when OC were initiated at late stages of dominant follicle development.

Regression and resurgence of the CL following PGF2α treatment 3 days after ovulation in mares

The present study was designed to characterize and compare the physiology and ultrasonographic morphology of the corpus luteum (CL) during regression and resurgence following a single dose of native prostaglandin F2alpha (PGF) given 3 days after ovulation, with a more conventional treatment given 10 days after ovulation. On the day of pre-treatment ovulation (Day 0), horse mares were randomly assigned to receive PGF (Lutalyse; 10 mg/mare, i.m.) on Day 3 (17 mares) or Day 10 (17 mares). Beginning on either Days 3 or 10, follicle and CL data and blood samples were collected daily until post-treatment ovulation. Functional and structural regression of the CL in response to PGF treatment were similar in both the Day 3 and 10 groups, as indicated by an abrupt decrease in circulating concentrations of progesterone, decrease in luteal gland diameter and increase in luteal tissue echogenicity. As a result, the mean +/- S.E.M. interovulatory interval was shorter (P < 0.0001) in the Day 3 group (13.2 +/- 0.9 days) than in the Day 10 group (19.2 +/- 0.7 days). Within the Day 3 group, functional resurgence of the CL was detected in 75% of the mares (12 of 16) beginning 3 days after PGF treatment, as indicated by transient major (6 mares) and minor (6 mares) increases (P < 0.05 and < 0.1, respectively) in progesterone. Correspondingly, mean length of the interovulatory interval was longer (P < 0.03) in mares with major resurgence (15.8 +/- 1.6 days) than in mares with minor (11.2 +/- 1.2 days) and no resurgences (13.5 +/- 0.3 days) in progesterone. Structural resurgence of the CL in the Day 3 group and functional and structural resurgence in the Day 10 group were not detected. In conclusion, PGF treatment 3 days after ovulation resulted in structural and functional regression of the CL and hastened the interval to the next ovulation, despite post-treatment resurgences in progesterone.

Ovarian follicular dynamics during conventional vs. continuous oral contraceptive use

OBJECTIVES

The purpose of this study was to characterize ovarian follicular and endometrial development during conventional vs. continuous oral contraceptive (OC) dosing regimens, to explore follicular development during the hormone-free interval (HFI) and to examine follicular development following OC discontinuation.

STUDY METHODS

A randomized clinical trial involving 36 clinically normal healthy women between the ages of 18 and 35 years (24.4 +/- 3.9, SEM). Transvaginal ultrasonography and blood sampling were done to ascertain ovarian function.

RESULTS

Fewer follicles > 4 mm developed during continuous vs. conventional OC use (p = .006). No dominant follicles developed during continuous OC use vs. eight dominant follicles (16.1 +/- 3.3 mm) during the conventional OC regimen. Two of eight (25%) dominant follicles ovulated. All dominant follicles began development during the HFI. Following discontinuation of OC use, ovulation took approximately 5 days longer when compared to natural cycles.

CONCLUSION

Continuous OC regimens more effectively prevent dominant follicle development and breakthrough ovulation. The slight delay in time to ovulation following OC discontinuation and natural cycles could be attributed to suppression of follicle wave activity.