Decline in fertility with age has been well documented in women. There are ethical limitations to use humans as a model for basic research, and there is a lack of well characterized animal model. The objective was to characterize and validate a bovine model for the study of age-associated subfertility. All experiments were conducted on the same group of 13-14 year old cows (n=10), and their 1-4 year old young daughters (n=10). Mother-daughter pairs were used to reduce genetic variations. <p>Follicular wave pattern in a natural reproductive cycle was maintained in old cows similar to that in daughters. We hypothesized that aging in cattle is associated with elevated circulating concentrations of FSH, and reduced concentrations of steroid hormones. As stated, circulating FSH concentrations were higher (P=0.009) during follicular waves in old than young cows. The ovulatory follicle in 2-wave cycles was smaller in old cows (P=0.04), but plasma estradiol concentrations were higher (P=0.01). Luteal phase progesterone tended to be lower in old than young cows (P=0.1). The number of 4-5 mm follicles recruited into a follicular wave was lower (P<0.05) in old cows than in their daughters.<p>The response to ovarian synchronization and superstimulatory treatments was compared between old and young cows. We hypothesized that aging in cattle is associated with decreased synchrony of an induced follicular wave after steroid treatment. Conversely, the emergence of an induced follicular wave was synchronous between age groups. The preovulatory LH surge was delayed in old compared to young cows (P=0.01), but the detected ovulation times were not different. Old cows had fewer (P<0.01) follicles equal or greater than 6 mm after superstimulation, and tended (P=0.1) to have fewer ovulations than their daughters (32±4 versus 40 ±3, respectively). The response of individual cows to successive superstimulatory treatments was correlated (r>0.8; P<0.0001). <p>The hypothesis of reduced oocyte developmental competence in old cows was tested by comparing embryo production and pregnancy rates between old and young cows. Fewer (P=0.04) embryos were recovered from old cows (6±2) than their daughters (12±2). A higher proportion (P<0.01) of unfertilized oocytes and/or uncleaved zygotes were recovered from old cows (222/312, 71%) than their daughters (119/316, 38%). The recovery of fewer embryos in old cows suggests reduced oocyte developmental competence. The survival of embryos after transfer into unrelated young recipients was similar between age groups. <p>The effects of advanced age on oocyte meiotic maturation and oocyte chromosome numbers abnormalities were studied in old and young cows. Our hypothesis of compromised oocyte meiotic maturation with age was not supported; similar or higher proportion of metaphase II oocytes were recovered from old than young cows. The abnormalities of oocyte chromosomal numbers were similar between age groups. <p>To conclude, endocrine, follicular and oocyte developmental changes in old cows are consistent with those reported for women approaching menopause. Therefore, our results validated the use of a bovine model to study age-associated subfertility in women. Unlike women, we did not detect an age-related increase in abnormalities of oocyte chromosome numbers in cattle.

A series of studies were guided by the principal hypothesis that it was necessary to characterize ovarian function during the seasons of the annual reproductive cycle in wapiti and that from this knowledge novel methods of exogenous control of ovarian function would be possible. To augment existing knowledge about endogenous control of ovarian function in wapiti studies were conducted to characterize ovarian follicle dynamics during the estrous season and to characterize ovarian follicular dynamics during the periods of transition into and out of the breeding season. The third study was designed to characterize ovarian follicle development and ovulation synchrony subsequent to an estrous synchronization protocol used commercially. To evaluate novel methods of exogenous control of ovarian function studies were conducted to determine if follicular wave emergence could be electively induced using hormonal or surgical treatments to evaluate novel ovarian superstimulatory treatment protocols. <p>It was concluded from the studies of ovarian function that follicle development during the breeding season was characterized by the regular and synchronous development of follicular waves and that 2, 3, or 4 waves occurred during each interovulatory interval. Transition into the breeding season was preceded by one short interovulatory interval (9 days) characterized by one wave of follicle development and a small, short-lived and hypo-functional corpus luteum. The last estrous cycle of the breeding season was similar to estrous cycles during the rut (21 days), but and transition to anestrus was marked by a failure of the dominant follicle to ovulate after luteal regression. The treatment protocol used commercially for estrous synchronization was effective, but unnecessarily long. It was concluded from the studies on exogenous control of ovarian function that follicular wave emergence could be electively induced using steroid hormones or follicle ablation and may be useful for estrus synchronization and superstimulatory protocols. The tested superstimulatory treatments were effective and had the advantage of reducing the treatment period by 6 days and the number of times the animals are handled by one third over a more conventional method. However, oocyte and embryo quality were not evaluated. <p>As a result of the studies conducted and one previous study during the anouvlatory season follicle and luteal dynamics are now known in wapiti for all seasons of the year and this knowledge will provide a template upon which other species of deer can be compared. The final two studies support the principal hypothesis. The novel methods of exogenous ovarian control tested increase the potential for success when applying reproductive technologies and the successful application of these methods in wapiti should lead to their successful use in other species of deer.

Polycystic ovary syndrome (PCOS) is an endocrine abnormality with multiple diagnostic criteria due to its heterogenic manifestations. One of the diagnostic criterion includes analysis of ultrasound images of ovaries for the detection of number, size, and distribution of follicles within the ovary. This involves manual tracing of follicles on the ultrasound images to determine the presence of a polycystic ovary (PCO). A novel method that automates PCO morphology detection is described. Our algorithm involves automatic segmentation of follicles from ultrasound images, quantifying the attributes of the segmented follicles using stereology, storing follicle attributes as feature vectors, and finally classification of the feature vector into two categories. The classification categories are PCO morphology present and PCO morphology absent. An automatic PCO diagnostic tool would save considerable time spent on manual tracing of follicles and measuring the length and width of every follicle. Our procedure was able to achieve classification accuracy of 92.86% using a linear discriminant classifier. Our classifier will improve the rapidity and accuracy of PCOS diagnosis, and reduce the chance of the severe health implications that can arise from delayed diagnosis.

Antral ovarian folliculogenesis involves recruitment of a cohort of small follicles, physiological selection of a dominant follicle, and ovulation. The mechanism of selection has not been precisely determined. Identification of the timing of preovulatory selection is a key component in understanding natural and peri-menopausal ovarian function, ovarian suppression for contraception, and improvement of ovarian stimulation protocols. Morphologic characteristics obtained by ultrasonography cannot be precisely quantitated by the human eye. Computer-assisted image analysis overcomes subjective human evaluation of ultrasonographic images.<p> The objectives of this research were to assess ultrasound image attributes of human dominant (DF) and 1st subordinate (SF1) ovarian follicles during natural menstrual cycles and following discontinuation of conventional and continuous oral contraceptives (OC). We utilized sophisticated computer algorithms to elucidate an association between image attributes and physiologic status of follicles. Transvaginal ultrasonographic images obtained in 2 previous studies were used to quantify changes that occur in ovarian follicles.<p> We detected quantitative differences between the dominant and largest subordinate follicles of ovulatory and major anovulatory follicular waves, as well as during the first wave following OC discontinuation. Differences in ultrasonographic image attributes were associated with the physiological status of follicles. Evidence of follicular dominance in follicles which develop during major ovulatory waves or following OC discontinuation can be detected prior to the time of selection manifest by differences in dominant and subordinate follicle diameters. In addition, differences in quantitative image attributes were detected between ovulatory and anovulatory DF. Follicles that develop following conventional and continuous OC administration schemes exhibit the same image characteristics.<p> Further research is necessary to elucidate the exact correlation of follicle image attributes during all stages of development with histological characteristics, prediction of the timing of DF selection and the effects of different OC formulations on follicle development during and following OC cessation. Computer-assisted image analysis of ultrasound images has the potential to develop into a diagnostic, prognostic, and research tool for the in vivo evaluation of ovarian physiology and pathology and elucidate biologically important times such as physiologic selection, ovulation of DF and characterization of abnormal follicles (i.e., follicular cysts, luteinized unovulated follicles).

Decline in fertility with age has been well documented in women. There are ethical limitations to use humans as a model for basic research, and there is a lack of well characterized animal model. The objective was to characterize and validate a bovine model for the study of age-associated subfertility. All experiments were conducted on the same group of 13-14 year old cows (n=10), and their 1-4 year old young daughters (n=10). Mother-daughter pairs were used to reduce genetic variations. <p>Follicular wave pattern in a natural reproductive cycle was maintained in old cows similar to that in daughters. We hypothesized that aging in cattle is associated with elevated circulating concentrations of FSH, and reduced concentrations of steroid hormones. As stated, circulating FSH concentrations were higher (P=0.009) during follicular waves in old than young cows. The ovulatory follicle in 2-wave cycles was smaller in old cows (P=0.04), but plasma estradiol concentrations were higher (P=0.01). Luteal phase progesterone tended to be lower in old than young cows (P=0.1). The number of 4-5 mm follicles recruited into a follicular wave was lower (P<0.05) in old cows than in their daughters.<p>The response to ovarian synchronization and superstimulatory treatments was compared between old and young cows. We hypothesized that aging in cattle is associated with decreased synchrony of an induced follicular wave after steroid treatment. Conversely, the emergence of an induced follicular wave was synchronous between age groups. The preovulatory LH surge was delayed in old compared to young cows (P=0.01), but the detected ovulation times were not different. Old cows had fewer (P<0.01) follicles equal or greater than 6 mm after superstimulation, and tended (P=0.1) to have fewer ovulations than their daughters (32±4 versus 40 ±3, respectively). The response of individual cows to successive superstimulatory treatments was correlated (r>0.8; P<0.0001). <p>The hypothesis of reduced oocyte developmental competence in old cows was tested by comparing embryo production and pregnancy rates between old and young cows. Fewer (P=0.04) embryos were recovered from old cows (6±2) than their daughters (12±2). A higher proportion (P<0.01) of unfertilized oocytes and/or uncleaved zygotes were recovered from old cows (222/312, 71%) than their daughters (119/316, 38%). The recovery of fewer embryos in old cows suggests reduced oocyte developmental competence. The survival of embryos after transfer into unrelated young recipients was similar between age groups. <p>The effects of advanced age on oocyte meiotic maturation and oocyte chromosome numbers abnormalities were studied in old and young cows. Our hypothesis of compromised oocyte meiotic maturation with age was not supported; similar or higher proportion of metaphase II oocytes were recovered from old than young cows. The abnormalities of oocyte chromosomal numbers were similar between age groups. <p>To conclude, endocrine, follicular and oocyte developmental changes in old cows are consistent with those reported for women approaching menopause. Therefore, our results validated the use of a bovine model to study age-associated subfertility in women. Unlike women, we did not detect an age-related increase in abnormalities of oocyte chromosome numbers in cattle.

A series of studies were guided by the principal hypothesis that it was necessary to characterize ovarian function during the seasons of the annual reproductive cycle in wapiti and that from this knowledge novel methods of exogenous control of ovarian function would be possible. To augment existing knowledge about endogenous control of ovarian function in wapiti studies were conducted to characterize ovarian follicle dynamics during the estrous season and to characterize ovarian follicular dynamics during the periods of transition into and out of the breeding season. The third study was designed to characterize ovarian follicle development and ovulation synchrony subsequent to an estrous synchronization protocol used commercially. To evaluate novel methods of exogenous control of ovarian function studies were conducted to determine if follicular wave emergence could be electively induced using hormonal or surgical treatments to evaluate novel ovarian superstimulatory treatment protocols. <p>It was concluded from the studies of ovarian function that follicle development during the breeding season was characterized by the regular and synchronous development of follicular waves and that 2, 3, or 4 waves occurred during each interovulatory interval. Transition into the breeding season was preceded by one short interovulatory interval (9 days) characterized by one wave of follicle development and a small, short-lived and hypo-functional corpus luteum. The last estrous cycle of the breeding season was similar to estrous cycles during the rut (21 days), but and transition to anestrus was marked by a failure of the dominant follicle to ovulate after luteal regression. The treatment protocol used commercially for estrous synchronization was effective, but unnecessarily long. It was concluded from the studies on exogenous control of ovarian function that follicular wave emergence could be electively induced using steroid hormones or follicle ablation and may be useful for estrus synchronization and superstimulatory protocols. The tested superstimulatory treatments were effective and had the advantage of reducing the treatment period by 6 days and the number of times the animals are handled by one third over a more conventional method. However, oocyte and embryo quality were not evaluated. <p>As a result of the studies conducted and one previous study during the anouvlatory season follicle and luteal dynamics are now known in wapiti for all seasons of the year and this knowledge will provide a template upon which other species of deer can be compared. The final two studies support the principal hypothesis. The novel methods of exogenous ovarian control tested increase the potential for success when applying reproductive technologies and the successful application of these methods in wapiti should lead to their successful use in other species of deer.

Polycystic ovary syndrome (PCOS) is an endocrine abnormality with multiple diagnostic criteria due to its heterogenic manifestations. One of the diagnostic criterion includes analysis of ultrasound images of ovaries for the detection of number, size, and distribution of follicles within the ovary. This involves manual tracing of follicles on the ultrasound images to determine the presence of a polycystic ovary (PCO). A novel method that automates PCO morphology detection is described. Our algorithm involves automatic segmentation of follicles from ultrasound images, quantifying the attributes of the segmented follicles using stereology, storing follicle attributes as feature vectors, and finally classification of the feature vector into two categories. The classification categories are PCO morphology present and PCO morphology absent. An automatic PCO diagnostic tool would save considerable time spent on manual tracing of follicles and measuring the length and width of every follicle. Our procedure was able to achieve classification accuracy of 92.86% using a linear discriminant classifier. Our classifier will improve the rapidity and accuracy of PCOS diagnosis, and reduce the chance of the severe health implications that can arise from delayed diagnosis.

Antral ovarian folliculogenesis involves recruitment of a cohort of small follicles, physiological selection of a dominant follicle, and ovulation. The mechanism of selection has not been precisely determined. Identification of the timing of preovulatory selection is a key component in understanding natural and peri-menopausal ovarian function, ovarian suppression for contraception, and improvement of ovarian stimulation protocols. Morphologic characteristics obtained by ultrasonography cannot be precisely quantitated by the human eye. Computer-assisted image analysis overcomes subjective human evaluation of ultrasonographic images.<p> The objectives of this research were to assess ultrasound image attributes of human dominant (DF) and 1st subordinate (SF1) ovarian follicles during natural menstrual cycles and following discontinuation of conventional and continuous oral contraceptives (OC). We utilized sophisticated computer algorithms to elucidate an association between image attributes and physiologic status of follicles. Transvaginal ultrasonographic images obtained in 2 previous studies were used to quantify changes that occur in ovarian follicles.<p> We detected quantitative differences between the dominant and largest subordinate follicles of ovulatory and major anovulatory follicular waves, as well as during the first wave following OC discontinuation. Differences in ultrasonographic image attributes were associated with the physiological status of follicles. Evidence of follicular dominance in follicles which develop during major ovulatory waves or following OC discontinuation can be detected prior to the time of selection manifest by differences in dominant and subordinate follicle diameters. In addition, differences in quantitative image attributes were detected between ovulatory and anovulatory DF. Follicles that develop following conventional and continuous OC administration schemes exhibit the same image characteristics.<p> Further research is necessary to elucidate the exact correlation of follicle image attributes during all stages of development with histological characteristics, prediction of the timing of DF selection and the effects of different OC formulations on follicle development during and following OC cessation. Computer-assisted image analysis of ultrasound images has the potential to develop into a diagnostic, prognostic, and research tool for the in vivo evaluation of ovarian physiology and pathology and elucidate biologically important times such as physiologic selection, ovulation of DF and characterization of abnormal follicles (i.e., follicular cysts, luteinized unovulated follicles).

Thesis (Ph. D.)--University of Virginia, 2000. / Spine title: Initiation of DNA replication. Department of Biochemistry and Molecular Genetics. Includes bibliographical references (142-171). Also available online through Digital Dissertations.

Thesis--University of Nijmegen. / Summary in English and Dutch. Includes bibliographical references (p. 101-108).