Point Absorber Limits to Future Gravitational-Wave Detectors.

High-quality optical resonant cavities require low optical loss, typically on the scale of parts per million. However, unintended micron-scale contaminants on the resonator mirrors that absorb the light circulating in the cavity can deform the surface thermoelastically and thus increase losses by scattering light out of the resonant mode. The point absorber effect is a limiting factor in some high-power cavity experiments, for example, the Advanced LIGO gravitational-wave detector. In this Letter, we present a general approach to the point absorber effect from first principles and simulate its contribution to the increased scattering. The achievable circulating power in current and future gravitational-wave detectors is calculated statistically given different point absorber configurations. Our formulation is further confirmed experimentally in comparison with the scattered power in the arm cavity of Advanced LIGO measured by in situ photodiodes. The understanding presented here provides an important tool in the global effort to design future gravitational-wave detectors that support high optical power and thus reduce quantum noise.

Threshold analysis of selected dose-response data for endocrine active chemicals.

Using a biologically relevant mathematical model, the Michaelis-Menten equation, we examined published data from endocrine active chemicals for evidence of no-threshold dose-response curves. Data were fit to a modified Michaelis-Menten equation which accounted for total background response. Subsequently, the data sets were analyzed using non-linear regression in order to estimate the four parameters of interest (non-hormone controlled background (Bnh), maximum response (Rmax), endogenous hormone level (D0), and the dose at which a half-maximal response was observed (ED50)) and to determine the fit to the fully modified Michaelis-Menten equation. Subsequently, response data were adjusted to account for Bnh and then normalized to Rmax, while dose data were adjusted to account for D0 and then normalized to the ED50. This data set was combined into a single, composite data set and fit to the fully modified Michaelis-Menten equation. We examined 31 data sets (24 endpoints) from studies on 9 different chemical/hormone treatments. Twenty-six of the data sets fit the modified Michaelis-Menten equation with high multiple correlation coefficients (r>0.90). The normalized data demonstrated a good fit to the modified Michaelis-Menten equation. These results indicate that a variety of biological responses fit the modified Michaelis-Menten equation, which does not have a threshold dose term.

The estrogen receptor relative binding affinities of 188 natural and xenochemicals: structural diversity of ligands.

We have utilized a validated (standardized) estrogen receptor (ER) competitive-binding assay to determine the ER affinity for a large, structurally diverse group of chemicals. Uteri from ovariectomized Sprague-Dawley rats were the ER source for the competitive-binding assay. Initially, test chemicals were screened at high concentrations to determine whether a chemical competed with [3H]-estradiol for the ER. Test chemicals that exhibited affinity for the ER in the first tier were subsequently assayed using a wide range of concentrations to characterize the binding curve and to determine each chemical's IC50 and relative binding affinity (RBA) values. Overall, we assayed 188 chemicals, covering a 1 x 10(6)-fold range of RBAs from several different chemical or use categories, including steroidal estrogens, synthetic estrogens, antiestrogens, other miscellaneous steroids, alkylphenols, diphenyl derivatives, organochlorines, pesticides, alkylhydroxybenzoate preservatives (parabens), phthalates, benzophenone compounds, and a number of other miscellaneous chemicals. Of the 188 chemicals tested, 100 bound to the ER while 88 were non-binders. Included in the 100 chemicals that bound to the ER were 4-benzyloxyphenol, 2,4-dihydroxybenzophenone, and 2,2'-methylenebis(4-chlorophenol), compounds that have not been shown previously to bind the ER. It was also evident that certain structural features, such as an overall ring structure, were important for ER binding. The current study provides the most structurally diverse ER RBA data set with the widest range of RBA values published to date.

Characterization and proteolytic activity of a cathepsin L-like polypeptide in endometrium and uterine flushings of cycling, pregnant and steroid-treated ovariectomized gilts.

Cathepsin L has been proposed to be involved with the endothelial-chorial type of placentation in the cat. Little information concerning the presence and secretion of cathepsin L is available for a species with noninvasive epitheliochorial placentation such as the pig. Cathepsin L activity in uterine flushings and endometrium from gilts during different days of the oestrous cycle and early pregnancy was analysed through specific substrate metabolism and Western blot analyses with antiserum against cat endometrial cathepsin L. This antiserum was utilized to determine the cellular localization of the enzyme within porcine endometrium. Cathepsin L activity within uterine flushings was elevated on Day 15 of the oestrous cycle and early pregnancy, with activity declining on Day 18. Cat cathepsin L antiserum cross-reacted with a group of 46, 40 and 38 kDa uterine proteins and detected a product within the surface and glandular epithelium of the endometrium. The appearance of the 40 kDa protein was first detected on Day 10 of the oestrous cycle with the 38 kDa proteins appearing on Day 15 and 18 of pregnancy. The 40 and 38 kDa uterine proteins appear to be steroid regulated as 12 days of progesterone administration is necessary to detect the proteins and cathepsin L activity.

Effect of unilateral ovariectomy, gonadotropin stimulation and immunization against a synthetic peptide of the inhibin alpha-subunit on follicular development and oocyte recovery in cattle.

Nulliparous Holstein cows were randomly distributed among 4 treatment groups to test the effects of treatments, including unilateral ovariectomy, anti-inhibin immunization and gonadotropin stimulation on ovarian follicle population and oocyte recovery. The Control treatment consisted of intact cows (I-Control). Unilaterally ovariectomized cows were included in the 3 remaining treatments consisting of ovariectomy alone (U-Control), cows immunized against a synthetic peptide of the alpha(c)-subunit of bovine inhibin (alpha(c)I; U-IH), and cows stimulated with FSH (Super-Ov; 75 units/female/week) and also immunized with alpha(c)I as in the previous treatment (U-IH/FSH). Oocytes were collected by transvaginal ultrasound-guided aspiration on a weekly basis from cows in each treatment for 5 consecutive weeks. Intact Control cows had a greater (P<0.05) number of follicles > or = 3 mm per female (4.7) than the U-Control and U-IH cows (2.6 and 2.9, respectively), and had a similar number of follicles as the U-IH/FSH treatment group (3.5). The numbers of follicles aspirated (2.7 to 3.6) and oocytes recovered/cow (1.6 to 2.6) were similar for cows in the I-Control, U-IH and U-IH/FSH treatment groups. Cows in the U-Control treatment group had a lower (P<0.05) number of aspirated follicles (2.0) and recovered oocytes (1.1) than the I-Control cows. Cows in the U-IH/FSH and U-IH treatments had follicles with larger (P<0.01) diameters (8.7 and 8.2 mm, respectively) than cows in the I-Control (6.6 mm) and U-Control (5.7 mm) treatments. In conclusion, unilateral ovariectomy did not result in compensatory increase of follicle number or size in the intact ovary; cows in the U-IH/FSH treatment group had a greater number of follicles aspirated than the U-Control cows. In addition, the anti-alpha(c)I immunization may have played a role in increasing the number and diameter of the follicles. None of the treatments evaluated in this study improved oocyte retrieval over that of the intact, nontreated cows.

High environmental temperature and humidity decrease oocyte quality in Bos taurus but not in Bos indicus cows.

Two experiments were conducted to assess the effects of environmental temperature and humidity on the quality and developmental capabilities of bovine oocytes. In Experiment 1, Bos taurus (Holstein and crossbred Angus) cows were subjected to 5 weekly sessions of ultrasound-guided follicle aspiration from February 16 through March 23 (cool season) and 5 sessions from May 22 through June 20 (hot season). In Experiment 2, Bos taurus (Holstein) and Bos indicus (Brahman) cows were superstimulated (Super-Ov) during the months of August (hot season) or January (cool season), and each cow was subjected to a single oocyte aspiration session. In each experiment, oocytes were classified as normal or abnormal based on ooplasm morphology and cumulus cell layers. In Experiment 1, oocytes classified as normal were in vitro matured and fertilized (IVM/IVF), and the resulting embryos cultured for 8 d. All oocytes recovered from superstimulated cows in Experiment 2 were matured and fertilized in vitro and the subsequent embryos cultured for 8 d, regardless of their morphological appearance. In Experiment 1, Bos taurus cows produced a higher (P = 0.02) percentage of normal oocytes during the cool season (75.9 +/- 8.0) than during the hot season (41.0 +/- 9.5). The percentage of fertilized oocytes developing to the 2-cell (82.4), 8-cell (65.4) and morula (46.6) stages were also greater (P < or = 0.06) during the cool season than the hot season (45.0, 21.2, 6.0 for 2-cell, 8-cell and morula stages, respectively). In Experiment 2, Bos taurus cows (Holstein) had a lower (P = 0.01) percentage of normal oocytes in the hot season (24.5 vs 80.0) and a lower (P < or = 0.003) percentage of fertilized oocytes developing to the 8-cell, morula and blastocyst stages. No difference (P > or = 0.57) in the percentage of normal oocytes or in embryo development was detected between seasons in Bos indicus (Brahman) cows. In conclusion, high environmental temperature and humidity resulted in a marked decline in the quality of oocytes retrieved from Bos taurus cows and markedly decreased their in vitro developmental capabilities. In contrast, a high percentage of oocytes retrieved from Bos indicus cows exhibited normal morphology and yielded a high proportion of blastocysts, regardless of season.

Electronic animal identification for controlling feed delivery and detecting estrus in gilts and sows in outside pens.

The objective of the present study was to evaluate the feasibility of delivering feed and detecting estrous behavior by computer-controlled equipment in a nonconfinement environment. In Exp. 1, gilts were assigned to treatment when detected pregnant by ultrasound at 30 to 35 d after artificial insemination. They were assigned to be fed individually in stalls once/day (0830) with a scoop (controls, n = 20) or with an electronic sow feeding station (ESF, n = 20). The ESF gilts received their feed in 98.6-g aliquots at 80-s intervals as they visited the feeding station. Control vs ESF gilts did not differ (P > .8) for backfat (2.2 vs 2.1 cm) or weight (170 vs 172 kg) before farrowing, total and live pigs/litter (9.3 and 8.7 vs 9.1 and 8.8), or litter birth weight (12.7 vs 12.1). In Exp. 2, proceptive behavior, as measured by visits to a boar's pen, were recorded electronically, and observed estrus was evaluated in two groups of sows during their first (n = 11) and second and third (n = 19) estrous cycles and in one group of gilts (n = 14). A partition prevented visual and physical contact between the boar and the visiting females except where the electronic estrus detection (EED) station was installed. Feed delivery software was used to monitor boar visitation even though no feed delivery equipment was present at the boar pen.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of sex ratio of the birth litter on subsequent reproductive performance of gilts.

Records on age at puberty from 1,555 gilts and total number of pigs born in litters of 1,187 gilts from the Nebraska gene pool population were used to evaluate the effects of uterine environment on subsequent reproductive performance. Independent variables were line, year, line x year, proportion of males in the birth litter (sex ratio), number born in the birth litter (fraternity size) and sex ratio x fraternity size. Sex ratio, fraternity size and their interaction influenced age at puberty (P less than .01) but not number born (P greater than .2). Partial regression coefficients indicated that age at puberty tended to decrease as sex ratio increased, particularly in small litters. Although the regression coefficients were relatively large, sex ratio, fraternity size and their interaction accounted for only 1.3% of the variation in age at puberty within line x year subclass. These results offer little encouragement for the use of sex ratio as a phenotypic selection criterion for improvement of reproductive performance in gilts. Results suggest that female swine are similar to rodents in response to uterine environmental effects.

An integrated "4-phase" approach for setting endocrine disruption screening priorities--phase I and II predictions of estrogen receptor binding affinity.

Recent legislation mandates the US Environmental Protection Agency (EPA) to develop a screening and testing program for potential endocrine disrupting chemicals (EDCs), of which xenoestrogens figure prominently. Under the legislation, a large number of chemicals will undergo various in vitro and in vivo assays for their potential estrogenicity, as well as other hormonal activities. There is a crucial need for priority setting before this strategy can be effectively implemented. Here we report an integrated computational approach to priority setting using estrogen receptor (ER) binding as an example. This approach rationally integrates different predictive computational models into a "Four-Phase" scheme so that it can effectively identify potential estrogenic EDCs based on their predicted ER relative binding affinity (RBA). The system has been validated using an in-house ER binding assay dataset for 232 chemicals that was designed to have both broad structural diversity and a wide range of binding affinities. When applied to 58,000 chemicals identified by Walker et al. as candidates for endocrine disruption screening, some 9100 chemicals were predicted to bind to ER. Of these, only 3600 were expected to bind to ER at RBA values up to 100,000-fold less than that of 17beta-estradiol. The method ruled out 83% of the chemicals as non-binders with a very low rate of false negatives. We believe that the same integrated scheme will be equally applicable to endpoints of other endocrine disrupting mechanisms, e.g. androgen receptor binding.

Studies of uterine secretions and products of primary cultures of endometrial cells in pigs.

The uterus plays a central role in the reproductive biology of mammals. Adaptation of the uterus from an oviparous to a viviparous nature required changes that involved production of a uterine environment that could support the development of the embryo and fetus. Production of a suitable environment includes the synthesis and secretion of products by the uterine endometrium. However, the uterine endometrium is not a single homogeneous unit, but rather consists of several cell populations. Recent accomplishments in cell culture techniques provide a means for examining the contributions and secretory control of different endometrial cell populations. Furthermore, it is possible to recombine specific cell types to study their interaction. It is clear that the luminal epithelium, glandular epithelium and endometrial stroma produce different secretory products. Some secretions (for example uteroferrin) are secreted by only one cell type; others (for example prostaglandins, PGs) are secreted by all types of cell. There is much to be learned about the functions and regulations of endometrial secretions and there are important aspects of the role of the endometrium in pregnancy that present concepts do not address. For example, there is no explanation for the required synchrony between the embryo and uterus before day 10 and the implications of control of the uterine environment by progesterone from day 4 to day 10 are not understood. Almost all of the uterine secretory proteins are produced after day 10. In this review, we consider the protein and prostaglandin products from the different cell populations of the pig endometrium and propose a model to explain the integration of multiple sources of PGs and multiple regulators of PG secretion. Our purpose is to facilitate a more complete understanding of the individual uterine cell populations and a better understanding of how these cell types interact to function as a complete unit.

Pettigrew technique of inducing whole-body hyperthermia.

The current use of heated wax as a surface contact heating source to induce whole-body hyperthermia (WBH) in the anesthetized patient is described. Heated anesthetic gases and epidural block are no longer routinely used. Hemodynamic, physiological, and biochemical changes are described. Deaths due to cardiac arrhythmias, disseminated intravascular coagulopathy, and liver failure have occurred rarely. Other complications included peripheral nerve palsies, mental disorientation, subclinical liver damage, decubitus ulceration, anemia, circumoral herpes simplex, lethargy, and anorexia. Transverse myelitis and coma occurred in 2 patients who had previously received high-dose irradiation to the spinal cord and cerebral region, respectively. The 232 patients in 4 centers have undergone 682 heating sessions. The method to produce prolonged WBH of 41.8 degrees C is simple and reliable.

Characterization of the muscarinic and serotoninergic receptors of the intestine of the rainbow trout (Salmo gairdneri).

The ability of carbachol and 5-hydroxytryptamine (5-HT) to contract isolated segments of rainbow trout intestine in a concentration-dependent manner indicates the presence of muscarinic and serotoninergic receptors in this tissue. The activity of these agonists appears to be directly on the smooth muscle, since ganglionic blockers and inhibitors of neurotransmission did not inhibit contractions. The carbachol-induced contractions were selectively inhibited by atropine and (+-)-3-quinuclidinyl xanthene-9-carboxylate hemioxalate hydrate, an M-2 muscarinic receptor antagonist. However, the inhibition was not competitive. McN-A-343, an M-1 muscarinic agonist had no effect on intrinsic tone. The 5-HT-induced contractions were selectively inhibited by methysergide and the 5-HT2 receptor blockers, ketanserin and 1-(1-naphthyl)piperazine. Again, the inhibition by these agents was not competitive. 5-HT1 and 5-HT3 receptor antagonists did not inhibit contractions. The results thus suggest that the smooth muscle of the rainbow trout intestine contains M-2 muscarinic and 5-HT2 receptors.

Peri-oestrous hormone profiles, embryonic survival and variation in embryonic development in gilts and primiparous sows.

The primary objective of this study was to determine whether embryo survival in gilts and primiparous sows is related to variations in the peri-oestrous profiles of oestradiol, progesterone and LH. A secondary objective of the present work was to compare embryo development and certain endocrine characteristics in gilts and primiparous sows. Sows (n = 6) and gilts (n = 6) were catheterized in the jugular vein on the day after weaning or on day 14 of the oestrous cycle, respectively. Additional females (one gilt and seven sows) were examined only for characteristics of embryonic development. Embryos were recovered on day 11.5-11.75 of gestation, and size and volume of individual embryos were recorded. Minimal differences were observed between sows and gilts for endocrine and embryo data. Embryo recovery was 71.38 +/- 4.77% based on the number of corpora lutea. However, endocrine differences were noted for pigs with high embryo survival (> 71% recovery) compared with those with low survival. Peak oestradiol concentration occurred closer (P < 0.05) to the onset of oestrus in pigs with high embryo survival than in pigs with low embryo survival (3.3 +/- 4.6 h after oestrus versus 13.0 +/- 5.5 h before oestrus) and peak LH concentration occurred later (P < 0.05) after the onset of oestrus for pigs with high embryo survival. Peak oestradiol concentration tended (P = 0.07) to be higher in pigs with low embryo survival (35.21 +/- 2.56 pg ml-1) compared with pigs with high embryo survival (28.17 +/- 2.14 pg ml-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of calcium channel blockers on pharmacologically induced contractions of rainbow trout (Oncorhynchus mykiss) intestine.

Calcium depletion/replacement studies were carried out to examine the role of calcium in contraction of trout intestinal smoot muscle in vitro. Three chemically distinct calcium channel blockers were used to determine whether voltage operated calcium channels (VOCs) were involved in calcium entry with either agonist or depolarization-induced contractions. Contractions induced by depolarizing intestinal smooth muscle with potassium were totally dependent on extracellular calcium, whereas receptor-mediated responses to 5-hydroxytryptamine (5-HT) and carbachol also relied on calcium derived from intracellular stores. The calcium channel blockers, verapamil, nitrendipine, and diltiazem, all shifted the calcium-response curve for potassium to the right, supporting the existence of VOCs in trout intestinal smooth muscle. The calcium-response curve for 5-HT was also shifted to the right, suggesting that 5-HT can induce calcium uptake into the smooth muscle via VOCs, in addition to mobilizing intracellular calcium. Verapamil also appeared to block 5-HT receptors directly. Carbachol-induced contractions were only reduced by diltiazem at low concentrations of calcium (0.1-1 mM), suggesting that diltiazem has some other mechanisms of action than the other calcium channel blockers. Activation of muscarinic receptors may induce calcium entry through channels other than the VOCs, in addition to mobilizing intracellular calcium.

Effects of three methods of selection for litter size in mice on pre-implantation embryonic development.

Characteristics of preimplantation embryonic development to Day 3.5 of gestation were evaluated in lines of mice after 21 generations of selection for litter size or components of litter size. Selection criteria were direct selection for number born (LS), selection on an index of ovulation rate and the proportion of ova shed that resulted in fully formed pups (IX), selection for number born in unilaterally ovariectomized females as an indication of uterine capacity (UT), and an unselected control (LC). Comparison of the average distributions of embryonic stage of development on the left side of the uterus showed that selection (average effect of LS, IX, and UT vs. LC) tended to advance (p = 0.07) the average stage of embryonic development at Day 3.5 and shift the distribution (p = 0.10) by increasing the frequency of expanded blastocysts and decreasing the frequency of pre-morula embryos. A similar shift in the distribution on the right side of the uterus was not statistically significant. Selection decreased (p = 0.06) variability in developmental stage among embryos within the right uterine horn. These selection criteria evaluated in the mouse appear to have changed the frequencies of genes that affect some determinants of average stage of embryonic development and uniformity of development within a uterine horn at Day 3.5 of gestation.

Roles of leukotrienes in bovine corpus luteum regression: an in vivo microdialysis study.

A microdialysis system (MDS) was surgically implanted into the corpora lutea (CL) of 12 normally cycling Holstein heifers. Heifers were either allowed to undergo spontaneous luteolysis (Spontaneous, n = 6) or received an intramuscular injection of prostaglandin F2 alpha (PGF2 alpha) on Day 12 of the estrous cycle (Induced, n = 6). The MDS was implanted on Day 11 in the induced heifers and on Day 17 in Spontaneous heifers. CL were perfused with Ringer's solution at a flow rate of 3 ml/hr beginning immediately after surgery. Dialysate samples were collected hourly for 3-4 days. Samples were assayed for progesterone (P4), oxytocin (OT), PGF, and leukotrienes B (LTB) and C (LTC). Dialysate OT was undetected in all but one Spontaneous and one induced heifer. Lipoxygenase products of arachidonic acid (AA) metabolism (LTB and LTC) in the dialysate were found to be closely associated with luteal regression. In Spontaneous heifers, the mean interval from the first hormone peak to the onset of P4 decline was similar for PGF, LTB, and LTC, with the first peak occurring at 12.8 +/- 8.1, 22.0 +/- 6.1, and 11.0 +/- 8.9 hr before the onset of P4 decline, respectively. The peak LTC value was greater (P < 0.05) than peak LTB or PGF. The 12-hr sampling interval with the highest LTC peak frequency was highly correlated (r = 1.0; P < 0.01) with the onset of P4 decline, but the highest LTB and PGF peak frequencies were not associated with the onset of P4 decline. Indeed, the mean numbers of PGF and LTB hormone peaks were higher (P < 0.05) after the onset of P4 decline than before. Administration of PGF2 alpha on Day 12 of the estrous cycle stimulated a decline in P4 secretion and an increase in the secretion of PGF, LTB, and LTC from the CL. In induced animals, the peak level of PGF was greater (P < 0.05) than peak LTB. These results suggest that the AA metabolites LTB and, especially, LTC play important roles during normal regression of the bovine CL.

Embryonic steroids and the establishment of pregnancy in pigs.

In the pig, establishment of pregnancy begins about 11-12 days after the start of oestrus. The ability of pig conceptuses to synthesize and release oestrogens during this period, as well as the ability of exogenous oestrogens to induce pseudo-pregnancy when administered from Day 11-15 of the oestrous cycle, provide evidence for an involvement of oestrogen in the maternal recognition of pregnancy in the sow. Oestrogen derived from the conceptus or from administration to cyclic gilts stimulates uterine secretion of calcium and specific polypeptides on Day 11-12. The specific roles for the uterine secretory response to oestrogen in the maintenance of pregnancy are unknown. However, it has been proposed that oestrogen prevents luteolysis in the sow through reorientation of endometrial prostaglandin release, i.e. into the uterine lumen rather than into the uterine vasculature. Oestrogen may interact with prolactin and/or conceptus secretory proteins to shift the direction of prostaglandin movement. Although conceptus oestrogen synthesis triggers a number of uterine secretory events on Day 11, a second sustained phase of oestrogen stimulation from Day 14 to 18 appears to be necessary for luteal maintenance beyond Day 25. Pig conceptuses synthesize and release large amounts of oestrogens between Days 14 and 18 of pregnancy. Conceptus oestrogens are clearly involved with the establishment of pregnancy. However, the conceptus also secretes a number of biologically active substances such as catechol oestrogens, prostaglandins and polypeptides which could interact with oestrogen to prevent luteolysis. The roles of these factors in control of vascular permeability, blood flow, placental attachment and immunological protection certainly indicate that, in addition to oestrogens, other factors are involved in the establishment of pregnancy in pigs.

Identification and characterization of bovine oviductal glycoproteins synthesized at estrus.

Published reports indicate that in several mammalian species the oviduct synthesizes and secretes specific glycoproteins which are components of the luminal fluids at the time of ovulation and fertilization. The present study characterized the secretory glycoproteins synthesized by the bovine oviduct at estrus. Oviducts obtained from four crossbred cows in estrus were flushed with saline, and segments of the ampullary and isthmic regions were fixed for immunocytochemical analyses. The remainder of the tissue was subjected to explant culture for 24 h in medium containing either 3H-leucine or 3H-glucosamine. Analysis of culture media by one- and two-dimensional SDS-PAGE followed by fluorography indicated that both the ampullary and isthmic regions synthesized a major class of Mr 97,000 glycoproteins with isoelectric points ranging from 5.5 to 8.1. A polyclonal antibody was generated to the glycoproteins after their isolation by gel filtration followed by electrophoretic separation. Western blot analysis of oviductal culture media indicated that the antisera cross-reacted with a doublet at Mr 97,000 and to a lesser extent with two additional bands at Mr greater than 200,000. Immunoreactive antigens were not identified in serum or in culture media of ovary, uterus, and nonreproductive tract tissues. The Mr 97,000 glycoproteins were present in oviductal flushings obtained from cows in estrus. They were also detected to a lesser degree in oviductal flushings obtained from cows at Days 5, 10, 15, and 18 of the estrous cycle, with the least amount of immunoreactivity being observed in Day 10 samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Uterine cellular changes in 2',5'-oligoadenylate synthetase during the bovine estrous cycle and early pregnancy.

The signal for maternal recognition of pregnancy in cattle is bovine trophoblast protein-1 (bTP-1), a Type I trophoblast interferon. One of the many functions of interferons is the induction of the 2',5'-oligoadenylate (2-5[A]) system, which is involved in cell division and selective degradation of mRNA. The present study focused on the cellular changes of 2-5(A) synthetase in bovine endometrium during the estrous cycle and early pregnancy. Ability of recombinant bTP-1 to stimulate activity of the enzyme in uterine cells throughout the estrous cycle was also evaluated in vitro. Surface epithelium, glandular epithelium, and stroma were enzymatically separated in cows on Day 5, 10, 15, or 18 postestrus and on Day 15 or 18 of pregnancy. Cell samples were lysed and frozen for determination of the endogenous cellular content of 2-5(A) synthetase. Additional cells obtained during the estrous cycle were cultured and treated with increasing doses of recombinant bovine interferon alpha (rbIFN-alpha) or recombinant bTP-1 (rbTP-1). During the estrous cycle, 2-5(A) synthetase was greatest on Day 5 and declined approximately 10-fold by Day 15 (p < 0.01). Cellular content of 2-5(A) synthetase was similar among all three endometrial cell types. In the gravid horn of pregnant animals, presence of a conceptus significantly increased (p < 0.01) 2-5(A) synthetase in all endometrial cell types compared to levels on Days 15 and 18 of the estrous cycle. On Day 18, levels of 2-5(A) synthetase were 30-fold greater (p < 0.01) in epithelium (surface and glandular) from pregnant cows compared to that from cyclic cows.(ABSTRACT TRUNCATED AT 250 WORDS)