Follicle Stimulating Hormone, Luteinizing Hormone and Testicular Leydig Cell Responses to Estradiol Immunization in Ile-de-France Rams

Active immunization of Ile-de-France rams against estradiol (E2) resulted in the production of E2-neutralizing antibodies and an elevation in the plasma concentrations of FSH, LH, and testosterone. The presence of E2 antibodies did not affect the testosterone metabolic clearance rate, indicating that the immunization-mediated 10-fold increase in plasma testosterone was the result of a 10-fold increase in testicular testosterone production. Testis weights, as well as nuclear and cytoplasmic volumes of individual peritubular and perivascular Leydig cells, were greater in E2-immunized rams than in albuminimmunized controls. Leydig cell numbers were not affected by treatment. The E2 antibodies were capable not only of neutralizing the inhibitory effects of endogenous E2 on gonadotropin levels in intact rams, but were able to block the effects of exogenously administered E2 on their FSH and Lii secretory response to castration. It is concluded that circulating E2 in the ram is involved in pituitary-testicular endocrine homeostasis and that E2 immunoneutralization can be employed to enhance testosterone secretion in this species

Stable Monopole-Antimonopole String Background in SU(2) QCD

Motivated by the instability of the Savvidy-Nielsen-Olesen vacuum we make a systematic search for a stable magnetic background in pure SU(2) QCD. It is shown that a pair of axially symmetric monopole and antimonopole strings is stable, provided that the distance between the two strings is less than a critical value. The existence of a stable monopole-antimonopole string background strongly supports that a magnetic condensation of monopole-antimonopole pairs can generate a dynamical symmetry breaking, and thus the magnetic confinement of color in QCD.Comment: 7 page

Faddeev-Niemi Conjecture and Effective Action of QCD

We calculate a one loop effective action of SU(2) QCD in the presence of the monopole background, and find a possible connection between the resulting QCD effective action and a generalized Skyrme-Faddeev action of the non-linear sigma model. The result is obtained using the gauge-independent decomposotion of the gauge potential into the topological degrees which describes the non-Abelian monopoles and the local dynamical degrees of the potential, and integrating out all the dynamical degrees of QCD.Comment: 6 page

Color Reflection Invariance and Monopole Condensation in QCD

We review the quantum instability of the Savvidy-Nielsen-Olesen (SNO) vacuum of the one-loop effective action of SU(2) QCD, and point out a critical defect in the calculation of the functional determinant of the gluon loop in the SNO effective action. We prove that the gauge invariance, in particular the color reflection invariance, exclude the unstable tachyonic modes from the gluon loop integral. This guarantees the stability of the magnetic condensation in QCD.Comment: 28 pages, 3 figures, JHEP styl

Secretion of parathyroid hormone-related protein by bovine mammary cells in vitro

Mammary cells were isolated from lactating cows at 1 to 6 weeks after calving and evaluated for their ability to secrete PTHrP in vitro. The tissue was enzymatically digested to release glandular acini. The digested acini were cultured on thin (1.0 mm) or thick (2.5 mm) layers of collagen. The cultures containing thick collagen were detached and allowed to contract on day 6. The culture medium consisted of M199 with prolation (8 µg/ml), insulin (5 µg/ml), cortisol (5 µg/ml), and fetal bovine serum (15%). PTHrP production was measured by N-terminal RIA and bioassay (stimulation of adenylate cyclase in the ROS 17/2.8 cell line). Medium was collected at 2-day intervals for 14 days. The cells reached confluence at 4–6 days. PTHrP production was low at day 2 (<0.5 ng/ml), but increased to peak production (2–4 ng/ml) at approximately day 6–8 of culture and remained constant until day 14. Immunoreactive and bioactive PTHrP levels in the culture medium correlated well. The cultures produced high levels of lactoferrin (500 to 3000 ng/ml) and low levels of α s1 -casein (14 to 77 ng/ml).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41592/1/774_2006_Article_BF02375695.pd

Food Sovereignty in the City: Challenging Historical Barriers to Food Justice

Local food initiatives are steadily becoming a part of contemporary cities around the world and can take on many forms. While some of these initiatives are concerned with providing consumers with farm-fresh produce, a growing portion are concerned with increasing the food sovereignty of marginalized urban communities. This chapter provides an analysis of urban contexts with the aim of identifying conceptual barriers that may act as roadblocks to achieving food sovereignty in cities. Specifically, this paper argues that taken for granted commitments created during the birth of the modern city could act as conceptual barriers for the implementation of food sovereignty programs and that urban food activists and programs that challenge these barriers are helping to achieve the goal of restoring food sovereignty to local communities, no matter their reasons for doing so. At the very least, understanding the complexities of these barriers and how they operate helps to strengthen ties between urban food projects, provides these initiatives with ways to undermine common arguments used to support restrictive ordinances and policies, and illustrates the transformative potential of food sovereignty movements

Reproductive effects of immunizing heifers against androstenedione and oestradiol-17β

Heifers were treated with saline (Group I, N = 10), keyhole limpet haemocyanin (KLH ; Group II, N = 10), androstenedione-KLH antigen (Group III, N = 14), or oestradiol-17β-KLH antigen (Group IV, N = 14). Booster injections were given to produce binding of \u3e 10% at dilutions of 1:100 to 1:1000 (50% binding = 14·4pg androstenedione and 9·5pg oestradiol). The heifers were mated and killed at ~46days of gestation to establish ovulation rates, calf numbers, blood hormone relationships and ovarian morphology. Ovulation rate in animals immunized against androstenedione (Group III) was significantly greater than in the other groups; 4 of the animals had double ovulations and 3 had twins. No significant differences were found between Groups I, II and IV in relation to ovulation or pregnancy rate and animals immunized against oestradiol-17β continued to cycle and become pregnant. Systemic progesterone, androstenedione and oestrogen levels were generally increased in Groups III and IV but the differences were not significant. No differences were detected between treatment groups in relation to CL weights, ovarian weights, follicle sizes or numbers. No binding of [3H]androstenedione or [3H]oestradiol-17β was detected in allantoic or amniotic fluids or fetal serum. Maternal antibody binding was correlated with binding of [3H]androstenedione and [3H]oestradiol in the follicular fluid sampled from the two largest follicles in the ovaries of each animal (Group III, r = 0·59;Group IV, r = 0·60;P \u3c 0·05). The response of increased ovulation rate in cattle immunized against androstenedione should be further investigated to study follicular recruitment and increased productivity

PULSATILE LUTEINIZING HORMONE SECRETION IN THE CASTRATE MALE BOVINE: EFFECTS OF TESTOSTERONE OR ESTRADIOL REPLACEMENT THERAPY

Luteinizing hormone (LH) secretory profiles have been determined for the male bovine following castration and steroid replacement therapy. Serum LH concentrations increased approximately threefold during the first week following castration and thereafter remained elevated (6.6 ± .7 ng/ml). Castrates not receiving steroid replacement showed a rhythmic pattern of LH release that was of high frequency (mean pulse interval; 85 ± 5 min) and high amplitude (mean peak concentration, 11.2 ± 1.4 ng/ml). Chronic administration of estradiol-17β via subdermal Silastic implants reduced mean serum LH concentrations (2.1 ± .3 ng/ml) and blocked the pulsatile pattern of LH release in all steers. Similar administration of testosterone suppressed mean serum LH and blocked pulsatile LH release in two of four animals. The number of implants used in this study provided physiological concentrations of estradiol (9.8 ± 1.5 pg/ml) and testosterone (4.1 + .2 ng/ml) in systemic blood for the two respective treatment groups. Differences in the LH secretory profiles among testosterone;implanted steers may have been related, in part, to differences in the amounts of steroid not bound to serum proteins. These findings demonstrate that estradiol is a particularly potent inhibitor of pulsatile LH secretion in the male bovine and suggest that gonadal steroid feedback on LH secretion may, in part, be imposed at the level of the hypothalamus. The mechanism for pulsatile LH release is discussed relative to a centrally-located luteinizing hormone releasing hormone pulse generator