Development of a progestin-based estrus synchronization program: I. Reproductive response of cows fed melengestrol acetate for 20 days with an injection of progesterone

We designed two experiments to determine the efficacy of an estrus control system in cows that combined long-term progestin exposure (20 d) with an acute increase in progesterone concentration. In Exp. 1, cows (n = 30) were fed either melengestrol acetate (MGA; .5 mg x cow(-1) x d(-1)) or ground ear corn (MGA carrier) for 20 d. On d -15 (last day of MGA feeding = d 0), cows were administered 25 mg of PGF2alpha to regress the corpus luteum (CL) and establish an environment conducive to the development of persistent follicles. To synchronously regress persistent follicles, cows fed MGA (n = 15) were injected with 200 mg of progesterone on d -2 (MGA-P), and the cows fed the MGA carrier were not treated (CONT; n = 15). Cows in the CONT group were artificially inseminated 12 h after detection of spontaneous estrus from d -20 to d 8. Estrus was observed, and all cows in the MGA-P group were artificially inseminated during the period of estrus synchronization (SYNC; d 1 to 8). No difference in conception rate was observed between treatments. In Exp. 2, postpartum cows (n = 113) received either the MGA-P (n = 56) or CONT (n = 57) treatment. More (P < .05) cows were observed in estrus during SYNC in the MGA-P (50%) than in the CONT (28%) group. Of the cows in the MGA-P group that were not observed in estrus during SYNC, 50% were in estrus for the first time 23 to 29 d after MGA withdrawal (SYNC2), suggesting that these cows ovulated without observable estrus during SYNC. Estrus was observed for the first time during SYNC2 in more (P < .05) cows in the MGA-P (25%) than in the CONT (7%) group. Conception rate at the synchronized estrus, pregnancy rate, and interval to first service and pregnancy were similar between treatments. We conclude that administration of MGA-P results in the synchronization and(or) induction of a fertile estrus in cows.     

Induced and synchronized estrus in cattle: dose titration of estradiol benzoate in peripubertal heifers and postpartum cows after treatment with an intravaginal progesterone-releasing insert and prostaglandin F2alpha

Seven cysteine-rich repeats form the ligand-binding region of the low-density lipoprotein (LDL) receptor. Each of these repeats is assumed to bind a calcium ion, which is needed for association of the receptor with its ligands, LDL and beta-VLDL. The effects of metal ions on the folding of the reduced N-terminal cysteine-rich repeat have been examined by using reverse-phase high-performance liquid chromatography to follow the formation of fully oxidized isomers with different disulfide connectivities. In the absence of calcium many of the 15 possible isomers formed on oxidation, whereas in its presence the predominant product at equilibrium had the native disulfide bond connectivities. Other metals were far less effective at directing disulfide bond formation: Mn2+ partly mimicked the action of Ca2+, but Ba2+, Sr2+, and Mg2+ had little effect. This metal-ion specificity was also observed in two-dimensional 1H NMR spectral studies; only Ca2+ induced the native three-dimensional fold. The two paramagnetic ions, Gd3+ and Mn2+, and Cd2+ did not promote adoption of a well-defined structure, and the two paramagnetic ions did not displace calcium ions. The location of calcium ion binding sites in the repeat was also explored by NMR spectroscopy. The absence of chemical shift changes for the side chain proton resonances of Asp26, Asp36, and Glu37 from pH 3.9 to 6.8 in the presence of calcium ions and their proximal location in the NMR structures implicated these side chains as calcium ligands. Deuterium exchange NMR experiments also revealed a network of hydrogen bonds that stabilizes the putative calcium-binding loop.     

Extension of corpus luteum lifespan and reduction of uterine secretion of prostaglandin F2 alpha of cows in response to recombinant interferon-tau

Two experiments tested the effect of recombinant ovine and bovine interferon-tau on corpus luteum lifespan, interestrous interval, and oxytocin-induced uterine secretion of prostaglandin F2 alpha. Cows received intrauterine injections of 100 micrograms of recombinant ovine interferon-tau plus 1.4 mg of BSA or of 1.5 mg of BSA alone in Experiment 1 and 200 micrograms of recombinant bovine interferon-tau plus 1.3 mg of BSA or 1.5 mg of BSA alone in Experiment 2. Twice daily injections (0700 and 1900 h) were split evenly between the uterine horns from d 14 to 24 of the experimental estrous cycle via an AI pipette in Experiment 1 and via intrauterine catheters in Experiment 2. On d 17, cows were injected with 100 IU of oxytocin, and plasma was collected for analysis of 13,14-dihydro-15-keto-prostaglandinF2 alpha. Recombinant ovine interferon-tau extended the lifespan of the corpus luteum (27.5 vs. 19.2 d) and interestrous interval (30.5 vs. 20.6 d) and abolished the oxytocin-induced increase in 13,14-dihydro-15-keto-prostaglandinF2 alpha, which peaked at 30 min for the BSA control group (210.8 pg/ml). Recombinant bovine interferon-tau also extended the lifespan of the corpus luteum (29.0 vs. 21.4 d) and interestrous interval (31.5 vs. 22.6 d) and abolished the oxytocin-induced increase in 13,14-dihydro-15-keto-prostaglandin F2 alpha, which peaked at 30 min for the BSA control group (205.6 pg/ml). In conclusion, recombinant ovine interferon-tau and recombinant bovine interferon-tau were effective antiluteolytic agents in cattle.     

A comparative study of plasma 17beta-oestradiol, progesterone, placental lactogen and chorionic gonadotrophin in abortion induced with intra-amniotic prostaglandin F2alpha

Serial estimations were made in plasma of 17beta-oestradiol (E2), progesterone and human placental lactogen (HPL) in 43 patients and of human chorionic gonadotrophin (HCG) in 34 patients during mid-trimester abortions induced with intra-amniotic prostaglandin F2alpha (PGF2alpha. Mean plasma concentrations of all the hormones showed a progressive fall after PGF2alpha. There was no relationship between the fall in levels of progesterone, HPL and HCG and the induction-abortion interval, signs of fetal distress or of intrauterine fetal death. Both the control level and the rate of fall of E2 were related to the induction-abortion interval and a rapid decline preceded intrauterine fetal death. The relationships of the progesterone/E2 ratio and the amniotic fluid volume/progesterone ratio to the induction-abortion interval were examined. The variation in the time at which significant falls in the concentration of individual hormones occurred was probably related to their respective half-lives in plasma.     

A study of prostaglandin F2alpha as the luteolysin in swine: II Characterization and comparison of prostaglandin F, estrogens and progestin concentrations in utero-ovarian vein plasma of nonpregnant and pregnant gilts

Polyvinyl catheters were inserted into the right and left utero-ovarian veins (UOV) and saphenous vein (SV) and artery (SA) of six non-pregnant (O) and five pregnant (P) gilts on day 11 after onset estrus. Beginning on day 12, UOV blood samples were collected at 15-min intervals from 0800 to 1100 hr and 2000 to 2300 hr, and single samples were taken at 1200 and 2400 hrs. Peripheral blood (SA or SV) was sampled at 0800, 1200, 2000 and 2400 hr until gilts returned to estrus (X = 20.6 days) or day 24 of pregnancy. UOV plasma PGF concentrations (ng/ml; n = 1929) were measured by RIA. Status (P vs O) by day interactions were detected (P less than .01) but variances among treatments were heterogenous (P less than .01). Curvilinear day trends were detected for PGF in 0 gilts (P less than .01) but not P gilts. PGF peaks, defined as concentrations greater than two SD above the mean concentration for each gilt, occurred with greater frequency (chi2 = 16.4; P less than .01) in O than P gilts; and mean peak levels (X +/- SE) were 5.04 +/- .27 and 3.84 +/- .13 ng/ml, respectively. Progesterone concentrations were maintained in pregnant pigs and were indicative of luteal maintenance. Systematic differences in day trends of utero-ovarian venous plasma estradiol were detected between O and P pigs. These differences may be of paramount physiological importance and are discussed.     

A comparative study of uterine activity in labour induced with prostaglandin F2alpha or oxytocin and in spontaneous labour. I. Pattern of the uterine contractions

The uterine contraction patterns and the changes in fetal heart rate (FHR) were studied in cardiotocographic recordings from 26 women in oxytocin-induced labour, 26 women in PGF2alpha-induced labour and 24 women during the later part of spontaneous labour. The contraction patterns and their effect on the FHR did not differ between the three groups. During the course of labour an increasing steepness of the upward slope of the contraction wave with increasing intensity of the contraction was found. High frequency of atypical contraction patterns, suggesting some degree of uterine incoordination was found during the active phase of labour in 10 patients, 8 of whom were primiparae. This incoordination could not be related to the effect of induction with either drug. Incoordinated contractions were associated with longer duration of labour and a tendency to more pronounced acidosis in the infant at birth, although mean values still fell in the normal range. Ominous FHR patterns were only seen in 2 cases of uterine hyperactivity during induction of labour.     

Evidence that Fe-NTA-induced renal prostaglandin F2 alpha is responsible for hyperplastic response in kidney: implications for the role of cyclooxygenase-dependent arachidonic acid metabolism in renal tumor promotion

Oxidative stress in a tissue activates phospholipase A2 which releases free arachidonic acid. In addition, a low grade oxidative tone also stimulates the tissue cyclooxygenase activity. Cyclooxygenase-dependent arachidonic acid metabolites such as PGF 2 alpha are known to play an important role in the development and maintenance of hyperplasia in skin in response to the application of tumor promoters. In this study we show that Fe-NTA, an oxidant renal tumor promoter induces PGF 2 alpha which was maximum at 12 hours after Fe-NTA treatment. However, at all time points studied, the elevated levels of PGF 2 alpha have been observed. As a result of the induction of PGF 2 alpha, the hyperplastic response can also be observed in the histopathology of the tissue. Additionally, an increased incorporation of [3H]thymidine in renal DNA has also been observed. Pretreatment of animals with indomethacin suppresses Fe-NTA-mediated hyperproliferation suggesting a role of cyclooxygenase in Fe-NTA-mediated stimulation of hyperplastic activity. The pretreatment of animals with the chain breaking antioxidants, Vit. E, BHA and BHT were only partially effective in inhibiting Fe-NTA-mediated PGF2 alpha production, further suggesting a role of non-free radical-dependent mechanism in its production. Our data suggest that Fe-NTA-induced PGF2 alpha through the activation of cyclooxygenase is responsible for the development and maintenance of hyperplasia in kidney.     

The possible mode of action of prostaglandins: X. Antagonism between prostaglandin F2a and prolactin or human chorionic gonadotropin: a comparative study

A comparative assessment of the efficacy of prolactin or HCG in reversing the luteolytic property of a single dose (2.0 mg/kg) of PGF2a was conducted in pregnant (day 10) rats. It was found that prolactin maintained pregnancy in 90% of the test animals. HCG though found to maintain pregnancy in 70% of the PGF2a-treated pregnants, the fetal survival rate was, however, recorded to be 62% against the control value of 98%. Conversely, prolactin replacement maintained the fetal survival rate as high as 93.4%. Moreover, the growth of the fetuses, placentae and corpus luteum in the pregnants having prolactin in conjunction with PGF2a was also found to be greater compared to the animals which had a combined regimen of PGF2a and HCG, but identical to controls. On the other hand, similar combined regimen when applied to hysterectomized pregnant rats, it was observed that though the vaginal diestrus was maintained by the prolactin or HCG in the presence of PGF2a, the prolactin regimen was found to be superb compared to HCG in the maintenance of luteal weight and functional activity. It was concluded that the antifertility effect of PGF2a in the rat is primarily the consequence of luteolysis and prolactin seems to be a much more appropriate hormonal replacement compared to HCG, a long-acting LH, in antagonizing the luteolytic property of PGF2a.     

Fate of the dominant follicle, embryonal survival, and pregnancy rates in dairy cattle treated with prostaglandin F2 alpha and progestins in the absence or presence of a functional corpus luteum

Our objective was to examine the role of progestin type on serum concentrations of progesterone (p4) and estradiol-17 beta (E2), ovarian follicular dynamics, and fertility in cattle in the presence or absence of a corpus luteum (CL) in an estrus synchronization scheme using progestin and PGF2 alpha. In Exp. 1, 325 cows and heifers were given one injection of PGF2 alpha (d 0) and then assigned randomly within parity to five treatments: to receive a second PGF2 alpha injection 14 d later (control); to receive norgestomet (NORG) for 7 d beginning on d 8, with a second PGF2 alpha injection given either 1 d (NORG + no CL) or 6 d (NORG + CL) after insertion; or to receive a P4-releasing intravaginal device (PRID) in lieu of norgestomet at comparable times. Presence or absence of a CL was based on concentrations of serum P4 on d 14. Pregnancy rates after insemination were greater (P < .01) with luteal treatments than with nonluteal treatments. Embryonal survival between two stages of pregnancy was 87.6%. In Exp. 2, ovarian structures in 50 cows were examined daily using ultrasonography and the same five treatments. Diameter of the ovulatory follicle was greater (P < .05) with the nonluteal treatments (NORG and PRID + no CL) than with the control and luteal treatments (PRID and NORG + CL). Replacement of the dominant follicle during progestin treatment was altered by treatment (luteal status) and stage of the estrous cycle. Fertility was not enhanced by exogenous progestins when a CL was present. In the absence of a CL, progestin (P4 less than NORG at the doses used) reduced fertility by increasing E2 and the diameter of the ovulatory follicle and decreasing turnover of dominant follicles.     

Classical conditioning of the rabbit eyelid response with a mossy-fiber stimulation CS: II. Lateral reticular nucleus stimulation.

Stimulation of mossy fibers arising from the pontine nuclei can be used as a conditioned stimulus (CS) during classical conditioning of the eyelid/nictitating membrane response (NM). In the present experiment we stimulated another source of mossy fibers, the lateral reticular nucleus (LRN), as a CS for NM conditioning. LRN stimulation was an effective CS, resulting in learning, and the conditioned response to LRN stimulation showed normal extinction. Unpaired presentation of CS and US did not result in pseudo-conditioning. Lesions of the cerebellar dentate-interpositus region abolished the conditioned response but left the unconditioned reflex response intact. We suggest that mossy fibers may normally carry CS information to the cerebellum. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunological status of septic and trauma patients. II. Proliferative response and production of interleukin 6 and tumor necrosis factor alpha by peripheral blood mononuclear cells from septic survivor, nonsurvivor and trauma patients: a correlation with the survival rate

OBJECTIVE: The reasons for conflicting prognostic results as to DNA ploidy and cell cycle variables (DNA index, percent S (%S) phase) may be found mainly at different levels of the flow cytometric methodology used. The present study concentrated on how many nuclei have to be measured with flow cytometry for reliable DNA histogram interpretation. STUDY DESIGN: Twenty-three samples of fresh frozen and 22 samples of paraffin-embedded material from different sites were used. For each sample, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 (x1,000) events were cumulatively measured. The resulting DNA histograms were analyzed with the MultiCycle computer program using a highly reproducible interpretation protocol. RESULTS: No disagreements about DNA ploidy classification were found in samples with 10,000 or more events for the fresh frozen and 40,000 or more events for the paraffin-embedded material. Excluding DNA ploidy disagreements, the DNA index was stable in all cases. To obtain a %S-phase cell measurement within 20% of the reference value, at least 20,000 and 40,000 events were needed for, respectively, DNA diploid and DNA nondiploid cases for the fresh frozen material and, respectively, 40,000 and 50,000 events for the paraffin-embedded material. CONCLUSION: For reliable combined determination of DNA ploidy, DNA index and %S-phase cells, at least 40,000 and 50,000 events are necessary for fresh frozen and paraffin-embedded material, respectively.     

Repeated administration of a F(ab')2 fragment of an anti-tumor necrosis factor alpha monoclonal antibody in patients with severe sepsis: effects on the cardiovascular system and cytokine levels

In an uncontrolled clinical trial the effects of repeated administration of the F(ab')2 fragment of a murine monoclonal anti-tumor necrosis factor alpha (TNF alpha)-antibody (MAK 195F) on cytokine levels and the cardiovascular system were studied in 20 patients with severe sepsis. Patients were treated with a total of 11 single dosages of the anti-TNF alpha-antibody intravenously over 5 days using either 1 mg/kg (n = 10) or 3 mg/kg (n = 10). The anti-TNF alpha-antibody was well tolerated in all patients without signs of toxicity and without development of anti-murine antibodies. As assessed by cytokine levels (TNF alpha, Interleukin-6) and hemodynamics there was no evidence that the higher dosage of the anti-TNF alpha-antibody (3 mg/kg per dose) was more effective than the lower dosage (1 mg/kg per dose). Comparison of our data with recent data from phase I or II trials using a complete murine monoclonal anti-TNF alpha-antibody suggest that the F(ab')2 fragments of the murine monoclonal anti-TNF alpha-antibody may be of similar efficacy. Definitive conclusions, however, with respect to improvement of mortality and improvement of the cardiovascular system, await the results of larger ongoing placebo-controlled trials.     

Heat transport and solidification in the electromagnetic casting of aluminum alloys: Part II. Development of a mathematical model and comparison with experimental results

In this second article of a two-part series, a mathematical model for heat transport and solidification of aluminum in electromagnetic casting is developed. The model is a three-dimensional one but involves a simplified treatment of convective heat transport in the liquid metal pool. Heat conduction in the solid was thought to play a dominant role in heat transport, and the thermal properties of the two alloys used in measurements reported in Part I (AA 5182 and 3104) were measured independently for input to the model. Heat transfer into the water sprays impacting the sides of the ingot was approximated using a heat-transfer coefficient from direct chill casting; because this heat-transfer step appears not to be rate determining for solidification and cooling of most of the ingot, there is little inaccuracy involved in this approximation. Joule heating was incorporated into some of the computations, which were carried out using the finite element software FIDAP. There was good agreement between the computed results and extensive thermocouple measurements (reported in Part I) made on a pilot-scale caster at Reynolds Metals Company (Richmond, VA).     

Development of a two-stage procedure for the automatic recognition of dysfluencies in the speech of children who stutter: II. ANN recognition of repetitions and prolongations with supplied word segment markers

This program of work is intended to develop automatic recognition procedures to locate and assess stuttered dysfluencies. This and the following article together, develop and test recognizers for repetitions and prolongations. The automatic recognizers classify the speech in two stages: In the first, the speech is segmented, and, in the second, the segments are categorized. The units that are segmented are words. Here assessments by human judges on the speech of 12 children who stutter are described using a corresponding procedure. The accuracy of word boundary placement across judges, categorization of the words as fluent, repetition or prolongation, and duration of the different fluency categories are reported. These measures allow reliable instances of repetitions and prolongations to be selected for training and assessing the recognizers in the subsequent paper.