Browsing by Subject "estradiol"
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Item Control of new follicular wave emergence and rate of follicular maturation in bos indicus-influenced cattle with estradiol benzoate, temporary calf removal and progesterone(2009-05-15) Pack, Julie DianeObjectives were to determine: 1) whether estradiol benzoate (EB) provides a superior alternative to GnRH for synchronizing emergence, growth and maturation of a new follicular wave for fixed timed AI (TAI) in Bos indicus-influenced cattle using CIDR-based protocols, 2) the effect of 48 h calf removal at CIDR removal on the rate of maturational synchrony of the dominant follicle and 3) the effect of varying the magnitude of peak plasma progesterone (P4) concentrations following CIDR insertion on the suppression of FSH and LH secretion in a CIDR-based protocol using EB. In experiment 1, sixty-four Braford (F-1) females were stratified by BCS, parity and days postpartum and assigned randomly to one of four groups in a 2 x 2 factorial arrangement of treatments: 1) Select-Synch + CIDR, 2) Select-Synch + CIDR with 48 h calf removal, 3) E-Synch + CIDR or 4) E-Synch + CIDR with 48 h calf removal. A greater number of cattle in the EB treated group exhibited NFWE compared to the GnRH group, 29 vs 17 cows for EB and GnRH respectively, (P<0.0006). Intervals to NFWE were also greater in EB treated cattle than in GnRH treated cattle, 4.2 vs 2.7 d for EB and GnRH treated cattle respectively, (P<0.0001). Proportions of GnRH- and EB-treated cows ovulating after CIDR removal did not differ. Post-CIDR suckling status did not affect ovulation frequency or interval to ovulation. In experiment 2, eight pubertal (F-1) heifers were used in a Latin Square design with four treatment levels of P4: 1) EB only, 2) EB and new CIDR, 3) EB and new autoclaved CIDR, 4) EB, new autoclaved CIDR and P4 injection at CIDR insertion. Treatments 2 through 4 increased (P < 0.01) mean plasma P4 concentrations compared to treatment 1, with treatment 4 creating the greatest increase in P4 with the longest duration. Suppression of plasma FSH was greatest in group 4 (P<0.08), with mean 60 h concentrations less than in all other groups. Mean concentrations of LH were lesser in group 4 than groups 1 and 2. Frequencies of occurrence of NFWE and ovulation and intervals to NFWE did not differ among treatments. Results indicate that the use of EB and CIDR to synchronize Brahman x Hereford females may provide better synchronization for TAI compared to GnRH and CIDR based protocols.Item Effects of isoflavones on reproductive functions of ram lambs(2012-05-12) Patton, Thor; Patton, Thor Addison; Salisbury, Micheal; Engdahl, Gil; Scott, Cody; Wegner, John; Angelo State University. Department of Agriculture.A study was conducted to determine if the isoflavones found in soybean‐based proteins were a detriment to ram lamb production and/or rate to puberty. New born Rambouillet and Suffolk ram lambs were randomly assigned either to the treatment (n=20) or control group (n=19). Treatment received soybean based feed from creep to finishing, while the control received cottonseed meal based feed. At weaning, serum samples and weights were collected to evaluate estradiol and testosterone levels. At an average of seven months of age, blood samples, final weights, semen samples and scrotal circumference measurements were taken. Scrotal circumference and weaning weight were decreased (p<0.05) and in general no other aspect was affected (p>0.05). However, numerically semen counts tended to be reduced. Additionally, estradiol was found to be higher at weaning (p>0.05) in the treatment and lower at final collection, testosterone acted inversely.Item Estradiol and MDMA affect the susceptibility and immune response to genital herpes and genital herpes immunization(2009-08-26) Jeffry Warren Pennock; Nigel Bourne, Ph.D.; Lawrence R. Stanberry, M.D., Ph.D.; Kathryn A. Cunningham, Ph.D.; Gregg N. Milligan, Ph.D.; D. Mark Estes, Ph.D.Herpes simplex virus type 2 (HSV-2), the most frequent cause of ulcerative genital herpes disease, has infected nearly one-in-five Americans and is even more prevalent in the developing world. The virus is also known to be a synergistic copathogen to HIV and may even facilitate its infection. Nonetheless, the vast majority of HSV-2-infected patients are unaware of their infection and are capable of asymptomatically transmitting the virus during sexual contact, thus a prophylactic vaccine is needed. Therefore, the research presented here examines a factor that could be important in enhancing susceptibility to genital herpes disease as well as one that could be important in enhancing vaccine-afforded protection against it. There is no HSV-2 prophylactic vaccine currently available but there is a subunit vaccine candidate in clinical trials which has shown efficacy in preventing disease in women. Using this vaccine candidate, we were able to demonstrate infection prophylaxis, improved disease prevention and modulated antibody production by complimenting vaccination with estradiol in a murine model. We also showed the effects of estradiol on vaccine efficacy in a guinea pig model. Findings of estradiol-enhanced vaccine efficacy are the first of their kind using a vaccine of this type and have potential clinical relevance to the development of other vaccines, as well as our understanding of gender differences in vaccine efficacy. Meanwhile, 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) was abused by over 1.2 million Americans in 2007 and is popular in the dance club, rave and circuit party scenes. MDMA and other similar drugs are reportedly associated with increased incidence of sexually transmitted infections, like HIV or genital herpes, and may have immunological effects. We were able to demonstrate that MDMA causes increased susceptibility to HSV-2 infection in mice and earlier onset of genital herpes disease. We also demonstrated an MDMA-effect on the cytokines of the innate immune system, both systemically and, for the first time, in the genital tract. These data suggest MDMA may have an important biological role in infection and that estradiol may have an important role in vaccine-elicited protection against it.Item Investigation of the relationship of body temperature, serum estradiol, and serum progesterone to the onset of parturition in the mare(2009-05-15) Morgan, Sommer ChristineIn cattle and sheep, a significant decrease in temperature has been noted prior to parturition. In the mare, similar temperature decreases have been documented, although results have been inconsistent when temperatures were taken rectally. One study reported a significant temperature decrease when using data from a radio transmitter inserted into the mare?s flank. The current study utilized nineteen Quarter Horse mares and one Thoroughbred mare, and was conducted from February to June 2006. Each mare had been previously implanted in the nuchal ligament with a microchip capable of reporting body temperatures. Blood collection and temperature recordings began 2 wk prior to each mare?s expected foaling date. Once the mare was estimated to be within 48 h of parturition, temperature was recorded every 3 h until parturition using both the microchip and rectal thermometer. Progesterone and estradiol 17-b were evaluated from daily blood samples from -10 to ? 5 d relative to foaling for determination of the relationship between these steroids and body temperature, time of foaling, birth weight and sex of foal. A significant decrease in rectal temperature (P < 0.05) was noted when the last temperature recorded was taken within 12h of parturition. Microchip data did not demonstrate any significant differences among readings before parturition. No significant difference was noted in the mean rectal temperature of all days relative to the sex of the neonate; however, microchip data showed mares carrying females to have a significantly (P < 0.05) higher mean rectal temperature of all days. Sex of the foal was not shown to be related to maternal concentrations of either progesterone or estradiol 17- b. A direct significant correlation between temperature and maternal plasma concentrations and progesterone and estradiol 17-b was found.Item The Protective Effects of Estradiol on Sporadic and Inflammation-associated Colon Cancer(2013-11-22) Armstrong, Cameron MichelleEpidemiological studies suggest pre-menopausal women have a reduced risk for sporadic and inflammation-associated colon cancer compared to post-menopausal women and men. The studies presented herein aim to determine the protective mechanisms of estradiol (E2) during sporadic and inflammation-associated colonic carcinogenesis. When investigating the role of E2 and fish oil at the earliest stage of sporadic colon cancer development, E2 had no effect on DNA adduct formation while dietary fish oil significantly reduced DNA adduct formation. Contrarily, E2 significantly induced apoptosis of damaged colonocytes while fish oil was not protective. In an in vivo model of inflammation-associated colon carcinogenesis with E2 administered following induction of DNA damage and initiation of inflammation, E2 treatment was associated with decreased colon tumor size and number in wild type (WT) but not estrogen receptor (ER) ? knockout (ER?KO) mice. Interestingly, apoptosis was reduced and proliferation increased by E2 in these tumors in WT mice. This may be due to the altered ER expression in these tissues as the tumors developed, with ER??expression decreasing concomitantly with ER? expression increasing. Contrary to the protective effect of E2 on inflammation-associated colon tumor formation, which was dependent on ER?, during acute inflammation in the colon E2 was protective against inflammation in both WT and ER?KO mice and injury in ER?KO mice. The protection against inflammation is likely due to the reduction of pro-inflammatory cytokine expression by E2. Apoptosis and proliferation were decreased and increased in the proximal and distal colon respectively in ER?KO mice. In vitro studies further elucidated the roles of ER? and ER? in colonocytes. E2 and ER?, but not ER?, specific agonists reduced cell number and induce apoptosis in nonmalignant colonocytes. This effect was lost in the presence of mutated p53. In ER? overexpressed nonmalignant colonocytes, E2 had no effect on cell number while ER? agonist and ER? agonists decreased and increased cell number respectively. These studies suggest that E2 is protective in the colon and ER? is required for protection against carcinogenesis but not protection against inflammation. Additionally, the protection against colon carcinogenesis is likely p53 mediated.