Research applications of ultrasonic imaging in reproductive biology.   总被引：5，自引：0，他引：5  

P G Griffin  O J Ginther 《Journal of animal science》1992,70(3):953-972

In the short time that transrectal ultrasonic imaging of the reproductive tract has been used as a research tool, many discoveries have resulted, some of which would otherwise have escaped detection for many years. Ultrasonography provides a wide array of morphologic information without invading or disturbing the tissues. Examinations can be done repeatedly over many days, or a dynamic event (e.g., ovulation) can be monitored in its entirety by continuous observation (e.g., 30 min). Inclusion of ultrasonic examinations in experimental protocols affords the opportunity to associate changing morphology with hormonal and other functional changes. If experimental testing is expected to involve changing morphology, ultrasonic imaging should be considered. End points can be measured or ranked and therefore data can be statistically analyzed for conventional hypothesis testing. The research potential of this technology and its adaptability for computer-assisted assessment go far beyond simplistic determination of ovulation, luteal formation, and pregnancy diagnosis. It is the authors' opinion that ultrasonic imaging is a revolutionary advance in reproductive research that is destined to rival the impact of other technologic breakthroughs, including radioimmunoassay.  相似文献   

Fate of conceptus and corpus luteum after induced embryonic loss in heifers   总被引：3，自引：0，他引：3  

J P Kastelic  O J Ginther 《Journal of the American Veterinary Medical Association》1989,194(7):922-928

Ultrasonography was performed to determine the fate of the conceptus and the corpus luteum after induced embryonic loss in heifers. When embryonic loss was induced by administration of prostaglandin F2 alpha (25 mg, IM) on day 28 (n = 10) or day 42 (n = 10), embryonic death occurred 2.3 +/- 0.2 (mean +/- SEM) and 2.6 +/- 0.2 days, respectively, after treatment, and subsequent ovulation occurred 2.4 +/- 0.3 and 2.7 +/- 0.2 days, respectively, after embryonic death. Administration of a mitotic inhibitor (1 mg of colchicine, intrauterine; n = 4) on day 42 resulted in embryonic death in 1.2 +/- 0.2 days and ovulation in 20.8 +/- 3.1 days after embryonic death. Rupture of the amnion on day 42 (n = 3) resulted in immediate death of the embryo and ovulation in 35 +/- 3.5 days. In prostaglandin-treated heifers, area of the corpus luteum decreased (P less than 0.01) between days -2 and -1, relative to day of embryonic death. Volume of uterine contents remained approximately constant for 2 or 3 days after treatment, then decreased greater than 75% between examinations on consecutive days. Embryonic death apparently resulted from luteolysis and was characterized by rapid loss of the conceptus with minimal conceptus degeneration; an intact conceptus was recovered from the vagina of 3 heifers treated on day 42. In heifers treated with colchicine or in which the amnion was ruptured, embryonic death was associated with maintenance of the corpus luteum and prolonged retention of the conceptus, which underwent extensive degeneration.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Circulating concentrations of immunoreactive inhibin and FSH during the estrous cycle of mares     

D.R. Bergfelt MS  B.G. Mann BS  N.B. Schwartz PhD  O.J. Ginther VMD  PhD 《Journal of Equine Veterinary Science》1991,11(6):319-322

A heterologous radioimmunoassay developed to measure inhibin in rat plasma was validated and used to characterize changes in peripheral concentrations of immunoreactive inhibin (ir-inhibin) in relation to follicle stimulating hormone (FSH) concentrations during the estrous cycle of mares. The primary antiserum used in the assay was developed against a synthetic porcine inhibin -subunit [(1-26)-Gly-Tyr] fragment. The same synthetic peptide was used for preparation of standards and tracer. Slopes of the dose-response curves for pooled estrus and diestrus mare plasma and equine follicular fluid were similar to the slopes for the porcine inhibin -subunit standard curve and porcine follicular fluid dose-response curve. Twelve mares were bled once daily beginning when diameter of the largest follicle reached ≤25 mm and continuing until 3 days after the end of an interovulatory interval (ovulation=Day 0). Each of the 12 interovulatory intervals were normalized to the mean length of the interovulatory interval (22.2 days; range, 19 to 26). There was an effect of day for concentrations of ir-inhibin (P<0.001) and FSH (P<0.006). Significant mean changes were as follows: 1) ir-inhibin decreased between Days 0 and 1, whereas FSH increased between Days 0 and 5; and 2) ir-inhibin increased between Days 7 and 12, whereas FSH decreased between Days 11 and 14. Mean concentrations of ir-inhibin and FSH were negatively correlated (r=-0.548; P<0.002). In conclusion, mean peripheral concentrations of ir-inhibin and FSH were inversely related during the estrous cycle of mares.  相似文献   

Doppler ultrasound in equine reproduction: principles, techniques, and potential     

O. J. Ginther VMD  PhD  Matthew D. Utt MS 《Journal of Equine Veterinary Science》2004,24(12):516-526

Doppler ultrasound is an emerging technology that has the potential to increase the diagnostic, monitoring, and predictive capabilities of equine theriogenologists and researchers. The technology is based on Doppler-shift frequencies, wherein the ultrasound frequency of echoes from moving red cells is increased or decreased as the cells move toward or away from the transducer. In spectral mode, the blood flow in a specific vessel can be assessed by placing a sample-gate cursor on the image of the lumen of the vessel. In addition, an angle cursor can be used to represent the angle of intersection of the ultrasound beams with the direction of blood flow (Doppler angle). The Doppler-shift frequency and the Doppler angle are used by the instrument for computing blood velocity. The focused results from placement of a sample gate in an artery are displayed by a spectrum that represents the changing velocities over time in association with the pulses of cardiac cycles. Peak systolic, end diastolic, and time-averaged maximum velocities are computed and shown for a selected cardiac cycle. Doppler indices (resistance index, RI; pulsatility index, PI) are ratios that are computed from various points on the spectrum. The indices are relatable to the hemodynamics of the tissue supplied by the artery. Increasing RI or PI values indicate increasing resistance and decreasing perfusion of the distal tissues. In color-flow mode, Doppler-shift frequencies are obtained from areas delineated by the operator on the B-mode image and are transformed and expressed as color-coded spots representing areas of blood flow. Vascular perfusion of a structure can be quantitated by the number of colored pixels in an image or can be estimated subjectively by the extent of the colored spots. The Doppler technology has the potential for providing information on the status and future success of a structure. However, realization of the expected potential will depend on future experience and research.  相似文献   

Do farmers manage weeds on owned and rented land differently? Evidence from US corn and soybean farms     

George B Frisvold  Joshua Albright  David E Ervin  Micheal DK Owen  Jason K Norsworthy  Katherine E Dentzman  Terrance M Hurley  Raymond A Jussaume  Jeffrey L Gunsolus  Wesley Everman 《Pest management science》2020,76(6):2030-2039

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On-the-farm incidence and nature of equine dystocias     

O.J. Ginther VMD  PhD  Deborah Williams DVM   《Journal of Equine Veterinary Science》1996,16(4):159-164

The characteristics of parturition and dystocia were recorded on standardized forms by foaling attendants on 8 farms for 517 spontaneous parturitions. Dystocias were classified from examination of the forms into those with malposition (involving the fetal body), malposture (involving fetal extremities), and normal position and posture in which traction was considered essential. Dystocias occurred in 58 of 517 (11.2%) parturitions and involved normal fetal position and posture (31.0%), malposition of body (22.6%), and malposture of extremities (41.4%). Other recorded frequencies were for emergence of an intact chorioallantois at the labia (2.0%), hiplock (1.2%), posterior presentation (0%), uterine torsion (0%), deformed fetal limbs *8.4%), stillbirth (1.2%), death of foal within 24 hours (1.2%), life-threatening injury to the mare (1.5%), and retained placenta (13.5%). The frequencies of a prolonged or excessive Stage 1 culminates in rupture of chorioallantois, (11.5%), deformed foal limbs (24.0%), relatively large foal (26.8%), and retained placenta (22.0%) were greater (P<0.05) for mares with dystocia than for mares without dystocia (2.6, 6.7, 7.9 and 10.5%, respectively).Ten of 14 (72%) dystocias with normal position and posture were attributable to a relatively large foal or weak maternal contractions. All of 16 malpositions of the body involved a tendency toward the dorso-pubic position (upside-down) and 31% were accompanied by malpostures of the extremities. Observations suggested that alternate standing and lying by the mare played a role in preventing and aiding in the self-correction of malpositions. Most (55%) of 24 malpostures involved retention of a front foot. The primary indicators of a problem were the absence of any fetal parts or membranes at the labia for a prolonged time after rupture of the chorioallantois (28% of dystocias) or the emergence of only one foot (34%).The interval from foal delivery to placental discharge was shorter (P<0.01) for Miniature Horses (17±3 min; n=17) than for the larger breeds (54±2 min; n=395). In 3 of 19 (16%) miniatures, the placenta and foal were delivered simultaneously. It was judged necessary to rupture manually an intact amnion in 2 of 5 miniatures on one farm.  相似文献   

Incidence, Endocrinology, Vascularity, and Morphology of Hemorrhagic Anovulatory Follicles in Mares   总被引：3，自引：2，他引：1  

O.J. Ginther VMD  PhD  E.L. Gastal DVM  PhD  M.O. Gastal DVM  PhD  M.A. Beg DVM  PhD 《Journal of Equine Veterinary Science》2007,27(3):130-139

The incidence of hemorrhagic anovulatory follicles (HAFs) is approximately 5% and 20% of estrous cycles during the early and late ovulatory season, respectively. The structures are more common in old mares (eg, >20 years), tend to occur repeatedly in individuals, and occur most frequently during the late follicular phase. In a recent study, the day of ovulation in controls and the first day of HAF formation, as indicated by cloudiness of follicular fluid, were defined as day 0. On day -1, future ovulating and HAF groups did not differ in follicle diameter or in the frequency of discrete gray-scale ultrasonic indicators of impending ovulation; however, in future HAFs, a greater percentage of the circumference of the follicle exhibited color-Doppler signals of blood flow. No differences were found between the two groups in systemic concentrations of progesterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) on days -4 to 2, but estradiol was elevated in the HAF group on day -3. The wall of the HAFs developed well-vascularized luteal tissue as indicated by echotexture and color Doppler signals and by the production of near normal levels of progesterone. In conclusion, HAFs formed from viable preovulatory follicles that did not differ from ovulatory follicles in diameter or gray-scale echotexture. Estradiol concentrations were elevated a few days before the failure of ovulation, and the wall of the follicle was more extensively vascularized on day -1.  相似文献   

Twin embryos in mares. I: From ovulation to fixation     

O J Ginther 《Equine veterinary journal》1989,21(3):166-170

Recent findings on the origin and development of twins from ovulation (Day 0) to fixation (mean: Day 16) are reviewed. Available data show that almost all twins originate from multiple ovulations. Results of recent ultrasound studies indicate that the number of days between double ovulations does not affect the conception rate per ovum or embryo survival during the first 16 days after each ovulation. Embryo reduction is the natural elimination of excess embryos so that only one embryo enters the foetal stage. In two studies, embryo reduction before or on the day of fixation was not considered an important aspect of the natural correction of twins. Diameters and growth rates on Days 11 to 16 were similar between singletons and twins and the presence of two vesicles did not have a direct effect on their diameter other than that attributable to their age. Twin and singleton embryonic vesicles were mobile within the uterine lumen from the first day of detection (Days 9 to 11) to the day of fixation (mean: Day 16). In one study, the embryonic vesicles were in the uterine body for over 50 per cent of the time during Days 9 to 12 and thereafter were most often in the uterine horns. For twins of dissimilar size, the preference for uterine body versus horns appeared to be an independent function of each vesicle based on its age or size. After Day 12, the number of entries from the uterine body into the horns increased and the vesicles began a maximum mobility phase which continued until fixation.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

The nature of embryo reduction in mares with twin conceptuses: deprivation hypothesis     

O J Ginther 《American journal of veterinary research》1989,50(1):45-53

Ultrasonography was used to determine whether there is embryo reduction in mares with unilaterally fixed twins when a major portion of the vascularized area of the wall of one of the embryonic vesicles is in apposition with the wall of the adjacent vesicle, rather than with the endometrium (deprivation hypothesis). In addition, the effect of ovulatory pattern (synchronous and asynchronous) on the incidence of embryo reduction was studied. Twin vesicles were ultrasonically detected on days 11 to 15 (ovulation = day 0) and were examined daily until there was embryo reduction or until day 40. In 31 mares with twin embryonic vesicles, unilateral fixation (71%) was more frequent (P less than 0.05) than was bilateral fixation (29%). In 28 mares with known ovulatory patterns, synchronous ovulations did not affect the type of fixation (9/17 unilateral and 8/17 bilateral); however, for asynchronous ovulators the frequency of unilateral fixation (10/11) was greater (P less than 0.01) than the frequency of bilateral fixation (1/11). The incidence of embryo reduction was greater (P less than 0.01) for unilateral fixation (14/19) than for bilateral fixation (0/9) and was greater (P less than 0.05) for asynchronous ovulators (9/11) than for synchronous ovulators (5/17). In mares with embryo reduction, the reduction was complete before detection of both embryo propers (early reduction) in 10/14 and after detection of both embryo propers (late reduction) in 4/14.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Regular and irregular characteristics of ovulation and the interovulatory interval in mares     

O.J. Ginther VMD  PhD  R.A. Pierson PhD 《Journal of Equine Veterinary Science》1989,9(1)

Characteristics of regular and irregular ovarian events were studied by daily ultrasound examination in 102 non-bred mares. The mean diameter of the prevoluatory follicle on the day before a single ovulation was significantly higher in April (46 mm) and May (48 mm) than in July (40 mm). Diameter was also significantly different among single (44 mm), double unilateral (35 mm), and double bilateral (40 mm) preovulatory follicles. The incidence of apparent anovulation within the ovulatory season was 4.7%. All apparent anovulations involved filling of the follicle with blood (hemorrhagic follicles). The incidence of diestrous ovulations was 4%. Prolonged interovulatory intervals occurred in 6 of 69 (9%) intervals. In 2 intervals (30 and 33 days), both the luteal and follicular phases were prolonged and no structural ovarian or uterine irregularities were detected. Three prolonged intervals (34, 41, and 49 days) were associated with hemorrhagic follicles and 1 was associated with a late diestrous ovulation (47 days). The condition known as spontaneous persistence of the corpus luteum, which is thought to be common in nonpregnant mares, was not detected in any of 69 interovulatory intervals.  相似文献