Roger Pierson

Exogenous control of follicular wave emergence in cattle

Variability in ovarian response to superstimulatory treatments and in the interval from PGF20 treatment to es&us in cattle is largely attributable to the status of follicular wave development at the time of treatment. To date, most treatments designed to control follicular wave development have been based on removal of the suppressive effect of the dominant follicle, either physically (by electrocauterization or ultrasound-guided follicle ablation) or hormonally (by GnRH or estradiol and progestogen treatment), and thereby induce the emergence of a new follicular wave at a specific time after treatment. Treatment of progestogen-implanted cattle with estradiol-17P (E-17P) resulted in suppression of the dominant follicle and emergence of a new follicular wave 4.3 d9.1 d later. Superstimulatory treatments initiated 4 d after E-17P treatment in progestogen-implanted cattle resulted in a superovulatory response comparable to that of cattle in which superstimulatory treatments were initiated on the second follicular wave. In another study, induced follicular wave emergence, regardless of the stage of the estrous cycle, resulted in similar superovulatory response and higher fertilization rates in heifers than when superstimulatory treatments were initiated 8 to 12 d after estrus (traditional approach). Finally, es&us synchronization treatments with E-17P plus progesterone and PGF2, have resulted in synchronous estms and ovulation. Overall, it appears that treatment with E- 17s and progestogen in combination may be used to effectively control and synchronize follicular wave development and may have important implications in artificial control of ovarian cyclicity and superovulation.

Characterization of Ovarian Follicular Wave Dynamics in Women

Abstract A wave phenomenon of ovarian follicular development in women has recently been documented in our laboratory. The objective of the present study was to characterize follicular waves to determine whether women exhibit major and minor wave patterns of follicle development during the interovulatory interval (IOI). The ovaries of 50 women with clinically normal menstrual cycles were examined daily using transvaginal ultrasonography for one IOI. Profiles of the diameters of all follicles ≥4 mm and the numbers of follicles ≥5 mm were graphed during the IOI. Major waves were defined as those in which one follicle grew to ≥10 mm and exceeded all other follicles by ≥2 mm. Minor waves were defined as those in which follicles developed to a diameter of <10 mm and follicle dominance was not manifest. Blood samples were drawn to measure serum concentrations of estradiol-17β, LH, and FSH. Women exhibited major and minor patterns of follicular wave dynamics during the IOI. Of the 50 women evaluated, 29/34 women with two follicle waves (85.3%) exhibited a minor-major wave pattern of follicle development and 5 women (14.7%) exhibited a major-major wave pattern. Ten of the 16 women with three follicle waves (62.5%) exhibited a minor-minor-major wave pattern, 3 women (18.8%) exhibited a minor-major-major wave pattern, and 3 women (18.8%) exhibited a major-major-major wave pattern. Documentation of major and minor follicular waves during the menstrual cycle challenges the traditional theory that a single cohort of antral follicles grows only during the follicular phase of the menstrual cycle.

A new model for ovarian follicular development during the human menstrual cycle

OBJECTIVE To evaluate changes in ovarian follicle dynamics during the human menstrual cycle to test the hypothesis that folliculogenesis occurs in a wave-like fashion. DESIGN Prospective longitudinal study. SETTING Healthy volunteers in an academic research environment. PATIENT(S) Fifty healthy women of reproductive age (range 19-43 years) with a history of regular menstrual cycles not taking medications known to interfere with reproductive function were evaluated. INTERVENTION(S) Transvaginal ultrasonography was performed daily for one interovulatory interval (IOI). MAIN OUTCOME MEASURE(S) Changes in the diameter and number of follicles > or =5 mm were evaluated. RESULT(S) Sixty-eight percent of women exhibited two waves of follicle development during the IOI and 32% exhibited three waves. Waves were characterized by an increase and subsequent decrease in the number of follicles > or =5 mm occurring in association with the growth of > or =2 follicles to > or =6 mm. A day effect and day by wave interaction were detected in the mean diameter of the largest three follicles and the number of follicles > or =5 mm. CONCLUSION(S) The follicular wave phenomenon in women provides a new model for ovarian function during the menstrual cycle and will improve our understanding of the ovarian response to fertility and hormonal contraceptive regimens.

Ovarian follicular wave emergence after treatment with progestogen and estradiol in cattle

Abstract An experiment was designed to evaluate the effects of treatment with progestogen and estradiol-17β (E-17β), in combination, at different stages of development of the dominant follicle, on follicular development and subsequent wave emergence. Cross-bred beef cows (n = 12) and heifers (n = 25) were randomly allocated to one of four treatment groups on Day 0 (ovulation). Treatment groups were untreated control animals and those that were given progestogen ear implants on Day 2, 5 or 8 and injected intramuscularly with 5 mg E-17β in sesame oil on Day 3, 6 or 9, respectively. Ovarian ultrasonography was performed daily from Day 0 until progestogen implant removal, 4 days after the emergence of the post-treatment follicular wave. The mean (± SEM) time (days) to cessation of growth and onset of regression of the dominant follicle of the first wave were earlier (P

Follicular wave dynamics after estradiol-17β treatment of heifers with or without a progestogen implant

Abstract Two experiments were designed to evaluate the effects of estradiol-17β (E-17β) on follicular wave dynamics and gonadotropin in cattle. The first experiment was designed to evaluate the effect of 5 mg E-17β administered on Day 1 (ovulation=Day 0) in heifers with or without a progestogen (SMB) ear implant. The dominant follicle in heifers treated with E-17β+SMB ceased to grow 1 d after E-17β treatment and subsequently regressed resulting in early emergence of the next follicular wave. Conversely, E-17β treatment of non-implanted heifers resulted in transient or incomplete suppression of the dominant follicle, and delayed emergence of the next follicular wave (P

Comparative Study of the Dynamics of Follicular Waves in Mares and Women

Abstract Deviation in growth rates of the follicles of the ovulatory wave begins at the end of a common growth phase and is characterized by continued growth of the developing dominant follicle (F1) and regression of the largest subordinate follicle (F2). Follicle diameters during an interovulatory interval were compared between 30 mares and 30 women, using similar methods for collecting and analyzing data. Follicles were tracked and measured daily by ultrasonography. Diameter at follicle emergence (mares, 13 mm; women, 6 mm) and the required minimal attained diameter for assessment of follicles (mares, 17 mm; women, 8 mm) were chosen to simulate the reported ratio between the two species in mean diameter of F1 at the beginning of deviation (mares, 22.5 mm; women, 10.5 mm). F1 emerged before F2 (P < 0.02) in each species, and the interval between emergence of the two follicles was similar (not significantly different) between species. Growth rate for F1 and F2 during the common growth phase was similar within species, and the percentage of diameter increase was similar between species. Proportionality between species in diameter of F1 at deviation (2.2 times larger for mares than for women) and at maximum preovulatory diameter (2.1 times larger) indicated that relative growth of F1 after deviation was similar between species. A predeviation follicle was identified in 33% of mares and 40% of women and was characterized by growth to a diameter similar to F1 at deviation but with regression beginning an average of 1 day before the beginning of deviation. The incidence of a major anovulatory wave preceding the ovulatory wave was not different between species (combined, 25%). Results indicated that mares and women have comparable follicle interrelationships during the ovulatory wave, including 1) emergence of F1 before F2, 2) similar length of intervals between sequential emergence of follicles within a wave, 3) similar percentage growth of follicles during the common growth phase, and 4) similar relative diameter of F1 from the beginning of deviation to ovulation. Similar follicle dynamics between mares and women indicate the mare may be a useful experimental model for study of folliculogenesis in women, with the advantage of larger follicle size.

BOVINE MODEL FOR STUDY OF OVARIAN FOLLICULAR DYNAMICS IN HUMANS

Abstract Ultrasonographic imaging has afforded the ability to characterize dynamic physiologic events as they occur and has been intensively applied in the study of ovarian function, particularly in the bovine species. Distinct similarities exist between the bovine and human species in ovarian form and function, but ovarian dynamics and related endocrine events have not yet been critically characterized in women. Practical and ethical limitations prohibit gross, endocrine and histopathologic verification of ultrasonographic observations made in humans in vivo; consequently, meaningful diagnostic and therapeutic regimens have not been devised to precisely control ovarian function or ameliorate ovarian dysfunction. The bovine ultrasound model is the most well developed model with regard to characteristics of ovarian follicular and luteal dynamics, and preliminary study has revealed that physiologic characteristics of bovine ovarian follicles may be reflected by visual data analysis of ultrasound images. A research strategy has been designed, based on the bovine ultrasound model, to study ovarian function in women using the non-human primate as an intermediate step. It is anticipated that newly developed techniques of controlling folliculogenesis in cattle may be appropriately modified for diagnostic and interventional procedures in women to augment or suppress fertility.

Effect of estradiol valerate on ovarian follicles, emergence of follicular waves and circulating gonadotropins in heifers

An experiment was designed to examine the effect of estradiol valerate (EV) on the growth and regression of follicles of a wave and on the emergence of the next follicular wave. Twenty-six beef heifers were xamined daily by ultrasonography and randomly allocated to 1 of 4 treatment groups at the time of ovulation (Day 0): unterated control heifers and those that received 5 mg EV intramuscularly on Day 1, Day 3 or Day 6. Maximum diameter of the dominant follicle was greater (P<0.05) in control heifers than in heifers treated on Day 1 or Day 3. Mean day of onset of regression of the dominant follicle was later (P<0.05) in control heifers than in heifers treated on Day 1 but was not different from heifers treated on Day 3. In heifers treated on Day 6, cessation of growth, maximum diameter and onset of regression were not different from that of control heifers. The emergence of the next follicular wave was earlier (P<0.05) in heifers treated on Day 1 than in control heifers, whereas wave emergence was delayed (P<0.05) in heifers treated on Day 3 or Day 6. The mean day of maximum concentration of FSH prior to the emergence of the next wave was earlier in heifers treated with EV on Day 1 and later in heifers treated on Day 3 or Day 6 compared with that of the controls (P<0.05). Treatment on Day 1 or Day 3 resulted in a significant LH surge in 8 13 heifers, whereas no LH surges were detected in control heifers or in heifers treated on Day 6. The hypothesis that EV suppresses the growth of the dominant follicle, was supported. Estradiol valerate treatment resulted in early emergence of the next follicular wave in heifers treated on Day 1, but treatment on Day 3 or Day 6 resulted in delayed emergence of the next follicular wave.

Changes in circulating hormone concentrations, testes histology and testes ultrasonography during sexual maturation in beef bulls

Nine groups of bull calves (n = 5 to 6 per group) were castrated every 5 wk from 5 to 45 wk of age, and the stages of spermatogenesis were identified histologically. Prior to castration, the testes of each calf were examined by ultrasonography, and the pixel intensities of the parenchyma were quantitated. Testis ultrasonograms were also recorded every 2 wk from 10 bull calves between 2 and 40 wk of age. Blood samples were collected at weekly intervals until castration. There was an early transient rise in circulating LH concentrations between 4 and 25 wk of age, while circulating FSH concentrations were high initially but decreased between 14 and 30 wk of age. Circulating testosterone concentrations increased gradually from 6 to 35 wk of age and then rapidly to 42 wk of age. There was a progressive increase in the more mature cell types during spermatogenesis as the animals aged, with the most dramatic changes occurring between 15 and 45 wk of age. Outer seminiferous tubule diameter increased between 10 and 45 wk of age, with the most rapid increase occurring from 30 wk of age. Inner tubule diameter increased between 30 and 35 wk of age. The echogenicity of the testes (as determined by ultrasonography) increased between 20 and 40 wk of age. From these data we conclude that testis echogenicity increased during the most active phase of growth of the seminiferous tubules as more mature germ cells were produced. Cessation of the early rise in gonadotrophin secretion immediately preceded this active phase of testicular development. Testosterone secretion rose markedly with the production of mature spermatozoa.

Multiresolution texture segmentation with application to diagnostic ultrasound images

A multiresolution texture segmentation (MTS) approach to image segmentation that addresses the issues of texture characterization, image resolution, and time to complete the segmentation is presented. The approach generalizes the conventional simulated annealing method to a multiresolution framework and minimizes an energy function that is dependent on the resolution of the size of the texture blocks in an image. A rigorous experimental procedure is also proposed to demonstrate the advantages of the proposed MTS approach on the accuracy of the segmentation, the efficiency of the algorithm, and the use of varying features at different resolution. Semireal images, created by sampling a series of diagnostic ultrasound images of an ovary in vitro, were tested to produce statistical measures on the performance of the approach. The ultrasound images themselves were then segmented to determine if the approach can achieve accurate results for the intended ultrasound application. Experimental results suggest that the MTS approach converges faster and produces better segmentation results than the single-level approach.