Expression of TRPM8 in sheep reproductive tissues and brain areas important for the expression of reproductive behavior

The Transient Receptor Potential Melastatin 8 (TRPM8) channel is a temperature-sensitive, calcium permeable ion channel and purported testosterone receptor. To determine how the hormone environment influences the expression of TRPM8 in gonadal tissue and areas of the brain important for reproduction, tissue from western white-faced cross-bred ewes, rams, and gonadectomized males (wethers; n = 6 per group) approximately 6 mo of age were collected. TRPM8 mRNA expression was greater (P = 0.01) in prostate of rams than wethers. Testes had greater (P = 0.004) expression of TRPM8 mRNA than the ovary. Differences in protein expression was similar with the testes having greater (P = 0.007) TRPM8 protein than the ovary. Protein expression did not differ (P = 0.6) in the prostate due to presence (ram) or absence (wether) of the testes. In the brain, TRPM8 varied in the amygdala with rams tending (P = 0.07) to express more mRNA which was reflected in greater (P = 0.04) number of neurons staining positive for TRPM8 in the central amygdala. Differences among ewes and wethers were not detected. This pattern was not observed (P ≥ 0.16) in the hypothalamus or olfactory bulb. To determine if TRPM8 was associated with the expression of ram sexual behavior, brains from rams categorized as high (n = 4) or low (n = 3) sexual activity were collected and blocked. Presence of TRPM8 channels was verified in the amygdala and hypothalamus of rams but was absent in the ventral tegmental area. Numbers of neurons staining positive for TRPM8 did not differ by expression of sexual behavior (P ≥ 0.2) in any area quantified. While expression of TRPM8 is more robust in tissues from intact males, expression of the channel does not appear to be important in the expression of sexual behavior.

Divining responder populations from survival data

BACKGROUND

Biomarkers that predict treatment response are the foundation of precision medicine in clinical decision-making and have the potential to significantly improve the efficiency of clinical trials. Such biomarkers may be identified before clinical testing but many trials enroll unselected populations. We hypothesized that time-varying treatment effects in unselected trials may result from identifiable responder subpopulations that may have associated biomarkers.

MATERIALS AND METHODS

We first simulated scenarios of clinical trials with biomarker populations of varying prevalence and prognostic and predictive associations to illustrate the impact of subgroup-specific effects on overall population estimates. To show a real-world example of time-dependent treatment effects resulting from a prognostic and predictive biomarker, we re-analyzed data from a published clinical trial (RTOG, Radiation Therapy Oncology Group, 9402). We then demonstrated a quantitative framework to fit survival data from clinical trials using statistical models incorporating known estimates of biomarker prevalence and prognostic value to prioritize predictive biomarker hypotheses.

RESULTS

Our simulation studies demonstrate how biomarker subgroups that are both predictive and prognostic can manifest as time-dependent treatment effects in overall populations. RTOG 9402 provides a representative example where 1p/19q co-deletion and IDH mutation biomarker-specific effects led to time-varying treatment effects and a considerable deviation from proportional hazards in the overall trial population. Finally, using biomarker data from The Cancer Genome Atlas, we were able to generate statistical models that correctly identified and prioritized a commonly used biomarker through retrospective analysis of published clinical trial data.

CONCLUSIONS

Biomarkers that are both predictive and prognostic can result in characteristic changes in survival results. Retrospectively analyzing survival data from clinical trials may highlight potential indications for which an underlying predictive biomarker may be found.

Depo-Provera increases neural activity in the central amygdala of reindeer bulls

Reindeer bulls are difficult to manage and dangerous to handlers during the rutting period. Progesterone agonists have been used anecdotally in the field to favorably influence behavior, but effects on reproductive signaling have not been determined. The objective of this study was to determine the effects of Depo-Provera (medroxyprogesterone acetate) on neural activity in the amygdala of reindeer bulls in the early (n = 4) and full (n = 4) rut. Treated bulls (n = 4) were injected with a single injection of Depo-Provera (400 mg i.m.) approximately 2 wk before rut was initiated. Control bulls were untreated. Bulls were exsanguinated and brains collected. Neural activity in the amygdala was determined using c-fos immunohistochemistry. Neural activity did not differ by treatment (P ≥ 0.5), collection period (P ≥ 0.5), or their interaction (P ≥ 0.3) in the medial and cortical amygdala nuclei. A treatment × time interaction (P = 0.009) was observed in the central amygdala. The amygdala nuclei are interconnected allowing for integration of sensory stimuli with a direct connection between the medial amygdala and the olfactory bulb. The central amygdala is responsible for alerting, fear, and initiating a state of arousal towards nonspecific stimuli in the surrounding environment. In wildlife, the central amygdala has a role in recognizing threats in the environment such as predators. During the rut, bulls normally have a decreased sense of fear and elevated aggressive behavior with Depo-Provera treatment seemly able to diminish that aggression. Although it is unlikely that this observed change in neural activity fully explains the decreased aggressive behavior noted in bulls treated with Depo-Provera, neural networks of aggression include the amygdala. It is possible that further changes in c-fos activity will be noted in other areas of the brain known to be necessary for processing social cues. Bulls treated with Depo-Provera maintain sexual interest and have offspring. Depo-Prevera increases the neural activity within the central amygdala and may partially account for their altered aggressive behavior during the rut.

Effects of maternal obesity on maternal and fetal plasma concentrations of adiponectin and expression of adiponectin and its receptor genes in cotyledonary and adipose tissues at mid- and late-gestation in sheep

Adiponectin potentially influences fetal weight by altering insulin signaling and trans-placental amino acid and glucose transporters. The objective of this study was to determine how maternal obesity influences maternal and fetal plasma concentrations of adiponectin, expression of fetal adiponectin, its receptors, and adipogenic genes at mid- and late-gestation. Blood samples and tissues were collected from obese and control multiparous pregnant ewes at day 75 or 135 of gestation. Although day of gestation or maternal obesity did not influence (P >  0.6) maternal plasma concentrations of adiponectin, fetal weight was increased (P <  0.001) and adiponectin tended to decrease (P =  0.10) at mid-gestation in fetuses from obese ewes. Differences were not apparent at late-gestation (P > 0.70). Relative abundance of adiponectin (P =  0.01), AdipoR2 (P =  0.04) and PPARγ (P =  0.01) mRNA was less at mid-gestation in fetal adipose tissue from obese mothers. By late gestation, maternal obesity tended to associated with a decrease in relative abundance of adiponectin (P =  0.09) and SREBF1 (P =  0.10) mRNA in fetal adipose tissue. Maternal obesity did not influence (P ≥  0.20) the relative abundance of adiponectin, AdipoR1 and AdipoR2 mRNA in cotyledonary tissue at mid or late- gestation. In conclusion, maternal obesity in sheep influences relative abundance of fetal adipose tissue mRNA for adiponectin and adipogenic, as well as plasma concentrations of total adiponectin. Although adiposity in pregnant ewes did not influence maternal adiponectin, maternal obesity potentially influenced fetal adipogenesis by altering the abundance of adiponectin, PPARγ and SREBF1 mRNA in fetal adipose tissue.

Whole brain radiotherapy after stereotactic radiosurgery or surgical resection among patients with one to three brain metastases and favorable prognoses: a secondary analysis of EORTC 22952-26001

Background

The absence of a survival benefit for whole brain radiotherapy (WBRT) among randomized trials has been attributed to a competing risk of death from extracranial disease. We re-analyzed EORTC 22952 to assess the impact of WBRT on survival for patients with controlled extracranial disease or favorable prognoses.

Patients and methods

We utilized Cox regression, landmark analysis, and the Kaplan-Meier method to evaluate the impact of WBRT on survival accounting for (i) extracranial progression as a time-dependent covariate in all patients and (ii) diagnosis-specific graded prognostic assessment (GPA) score in patients with primary non-small-cell lung cancer (NSCLC).

Results

A total of 329 patients treated per-protocol were included for analysis with a median follow up of 26 months. One hundred and fifteen (35%) patients had no extracranial progression; 70 (21%) patients had progression <90 days, 65 (20%) between 90 and 180 days, and 79 (24%) patients >180 days from randomization. There was no difference in the model-based risk of death in the WBRT group before [hazard ratio (HR) (95% CI)=0.70 (0.45-1.11), P = 0.133), or after [HR (95% CI)=1.20 (0.89-1.61), P = 0.214] extracranial progression. Among 177 patients with NSCLC, 175 had data available for GPA calculation. There was no significant survival benefit to WBRT among NSCLC patients with favorable GPA scores [HR (95% CI)=1.10 (0.68-1.79)] or unfavorable GPA scores [HR (95% CI)=1.11 (0.71-1.76)].

Conclusions

Among patients with limited extracranial disease and one to three brain metastases at enrollment, we found no significant survival benefit to WBRT among NSCLC patients with favorable GPA scores or patients with any histology and controlled extracranial disease status. This exploratory analysis of phase III data supports the practice of omitting WBRT for patients with limited brain metastases undergoing SRS and close surveillance.

Clinical Trials Number

NCT00002899.

Tyrosine hydroxylase in the ventral tegmental area of rams with high or low libido-A role for dopamine

Dopamine synthesis in the ventral tegmental area (VTA) is necessary for the reinforcement of sexual behavior. The objective of this study determined if sexual stimuli initiates reward, and whether reward is attenuated in sexually inactive rams. Sexually active rams were exposed to urine from estrous (n=4) or ovariectomized (n=3) ewes with inactive rams (n=3) exposed to urine from estrous ewes. Following exposure, rams were exsanguinated and brains perfused. Alternating sections of the VTA were stained for Fos related antigens (FRA), tyrosine hydroxylase, and dopamine beta-hydroxylase activity. Forebrain tissue, mid-sagittal ventral to the anterior corpus callosum, was stained for dopamine D2 receptors. Concentrations of cortisol was determined prior to and following exposure. Exposure to ovariectomized-ewe urine in sexually active rams did not influence (P=0.6) FRA expression, but fewer (P<0.05) neurons were positive for tyrosine hydroxylase in the VTA. Sexually inactive rams had fewer (P<0.05) FRA and tyrosine hydroxylase positive neurons in the VTA than sexually active rams following exposure to estrous ewe urine. VTA neurons staining positive for dopamine beta-hydroxylase did not differ by sexual activity (P=0.44) or urine exposure (P=0.07). Exposure to stimulus did not influence (P=0.46) numbers of forebrain neurons staining positive for dopamine D2 receptors in sexually active rams, but fewer (P=0.04) neurons stain positive in inactive rams. Serum concentrations of cortisol did not differ (P≥0.52) among rams prior to or following stimulus. In conclusion sexual inactivity is unlikely due to stress, but may be partially a result of decreased tyrosine hydroxylase and/or the response to dopamine.

Sunlight exposure increases vitamin D sufficiency in growing pigs fed a diet formulated to exceed requirements

Traditional confinement practices limit exposure to sunlight and vitamin D synthesis, and vitamin insufficiency occurs even with dietary supplementation. The aim of this study was to determine the effect of limited sun exposure on serum concentration of vitamin D and the expression of vitamin D synthesizing enzymes in the liver and kidney of pigs on a vitamin D sufficient diet. White-pigmented grower pigs (29.7 ± 2.3 kg) fed 15% CP diet ad libitum providing >1,200 IU vitamin D₃/kg of feed were exposed to sunlight for 1 h each day at solar noon for 14 d at the spring equinox (March pigs, n = 10) or summer solstice (June pigs, n = 5) and again before slaughter in June (March pigs) and September (June pigs). Blood for the analysis of 25(OH)D was collected before and after sunlight exposure. Traditionally housed pigs served as controls. After initial sun exposure, blood samples were collected from June pigs daily for 5 d and weekly for 8 wk to determine vitamin D3 and 25(OH)D decay, respectively. Kidney and liver samples were collected from the June pigs at slaughter after sun exposure for analysis of messenger RNA expression of vitamin D binding protein and synthesizing/degrading enzymes. Average daily gain (ADG) was not influenced (P > 0.5) by sunlight exposure. June pigs had fewer days on feed, lower (P = 0.003) ADG and were slaughtered at a lighter (P < 0.001) weight. Exposure to sunlight increased (P < 0.001) 25(OH) vitamin D for all pigs. March pigs, obtained from a Midwest producer, had lower (P < 0.001) concentration of 25(OH)D than June pigs born on-farm. Initial sunlight exposure increased serum concentration of 25(OH)D in March pigs by 200% and June pigs by 67%. Serum concentration of vitamin D3 was decreased (P < 0.05) by 72 h with 25(OH)D decreased (P < 0.05) by wk 4 after exposure. Expression of vitamin D binding protein, vitamin D synthesizing CYP2R1, CYP27A1, CYP2D25, or degrading enzyme CYP24A1 were not influenced (P ≥ 0.19) by sunlight exposure. Expression of CYP27B1 was decreased (P = 0.04) in the kidney but tended to be increased (P = 0.06) in the liver after sun exposure. These results suggest limited sun exposure can efficiently increase serum concentration of vitamin D in growing pigs with varying levels of vitamin sufficiency. The lack of major changes in vitamin synthesizing enzymes suggests the 14-d exposure period did not saturate the capacity of slaughter-weight pigs to synthesize vitamin D.

50 years of the Wyoming ram test: How sheep have changed

Production characteristics of white-faced rams have been systematically evaluated over a 140-d test in Wyoming since 1961. Individual test records ( = 4,240) from rams on test were analyzed to determine change over the past 52 yr. Although rams on test are not older, weight on and off test has increased ( < 0.001) since 1961. Weight off test increased 22.7 kg and contributed to an increase ( < 0.001) in clean fleece weight. Rate of gain ( < 0.001) almost doubled over this 50-yr period. Growth efficiency improved from 0.23 ± 0.01 kg/d from 1961 to 1966 to 0.39 ± 0.01 kg/d from 2008 to 2013. Cubic, rather than linear, effects better explain the change in growth characteristics, suggesting a plateau or tapering of these traits. Wool characteristics remain an important component of the test index, and despite increases in body size and gain, wool diameter was unchanged ( > 0.15). Average daily gain correlated ( > 0.67; < 0.001) with lamb and feeder lamb price, with the strongest correlation at a 2-yr ( > 0.76) time lag. U.S. sheep inventory was negatively correlated ( > -0.72; < 0.001) with sheep price and ADG, with the greatest correlation at no time lag. Wool price 0, 2, or 5 yr prior did not correlate ( < 0.1; ≥ 0.5) with spinning count. Influences on white-faced ram selection appear to have largely impacted growth traits while avoiding negative impacts on wool quality.

Effects of progesterone and RU486 on the development and expression of adult male sexual behaviour and gene expression in the amygdala and preoptic area of the hypothalamus

The number of progesterone receptors is greater in the male than female neonatal rat hypothalamus. The aims of the present study were to determine developmental effects of progesterone on the expression of adult male sexual behaviour and whether changes in behaviour were reflected by altered gene expression within the hypothalamic preoptic area (POA) or medial amygdala. Male rats were treated with progesterone (40 µg kg–1, i.p.), the progesterone receptor antagonist RU486 (40 µg kg–1, i.p.) or an equal volume of vehicle (10% ethanol, 90% corn oil) on postnatal Days 1–5. Treatment with either progesterone or RU486 inhibited (P ≤ 0.07) the initial expression of consummatory sexual behaviour at 10.5 weeks of age without influencing growth or serum concentrations of testosterone. Sexual interest, as measured by latency to exhibiting mounting behaviour or the number of mounts achieved, was not influenced by treatment with either progesterone or RU486. The effects of treatment with progesterone or RU486 on sexual behaviour were diminished by experience. Microarray analysis of the POA indicated 61 genes that were upregulated and 49 that were downregulated (P ≤ 0.01) following RU486 treatment of male rats. However, the altered expression of selected genes was not confirmed by real-time reverse transcription–polymerase chain reaction. The expression of targeted genes within the amygdala was not influenced by treatment with either progesterone or RU486. Neonatal treatment with RU486, but not progesterone, decreased testes weight (P = 0.02) without affecting testes morphology. The results indicate that altering the progesterone environment during a critical developmental period affects the expression of behaviour, but that changes in behaviour are not mirrored by the altered expression of selected genes.

Hydrodynamic measurement of double-layer repulsion between colloidal particle and flat plate

Electrostatic repulsion acting across an electrolyte solution lends stability to paints and printing inks and influences cell adhesion, aggregation, and fusion. A new technique is used to measure this interaction when one of the bodies has colloidal dimensions. The potential energy profile of interactions between a 15-micrometer polystyrene sphere and a glass plate is determined by observing the distribution of separation distances (0.2 to 0.4 micrometer) that the particle samples by Brownian motion. Measurements of the speed with which the sphere is carried by linear shear flow along the wall are used to calculate separation distance. Although evidence for hydrodynamic lift is found, it is not included in the potential profile.

DNA repair protein biomarkers in triple negative breast cancer

Abstract #1064

Introduction: Triple negative breast tumors form a distinct, aggressive, subgroup of breast cancers that exhibit a high degree of genomic instability and have many phenotypic similarities to BRCA1 deficient tumors. These observations suggest that aberrant DNA repair may be involved in triple negative tumor carcinogenesis. We profiled tumor DNA repair capacity using immunohistochemistry in order to develop prognostic biomarkers and suggest targets for novel therapies.&#x2028; Methods: We identified 143 previously treated women with triple negative breast cancers and used their archived, formalin-fixed, paraffin-embedded primary excision biopsies to create a tissue microarray (TMA). The TMA was stained using antibodies against proteins in various DNA repair pathways including XPF, FANCD2, PAR, MLH1, and MK2. Stained tissue was evaluated using machine-based image analysis and scoring that represented both the intensity and quantity of positive tumor nuclei. Biomarker scores and clinical data were assessed for correlations with outcome. Patients were randomized into training and test cohorts for the development of a multiple marker model. A set of critical threshold marker values were determined that maximally separated the training samples into low and high risk recurrence groups. Training set thresholds and marker combinations were applied towards the test set. Kaplan-Meier and Cox proportional hazards were used to test time to recurrence.&#x2028; Results: Clinical data for 115 patients with primary treatment data was available with a median follow up of 58 months. There were 37 recurrences: 18 were distant first, 12 were local first and 7 were simultaneous. Low XPF (p=0.002), pMK2 (p=0.02), MLH (p&lt;0.001) and FANCD2 (p=0.05) were associated with shorter time to recurrence. In the training cohort, the high-risk group defined by a four marker model had a relative risk of recurrence of 3.0 (p&lt;0.00001) and shorter median time to recurrence than the low risk group (13.1 months versus not reached). This was superior to single markers and to other markers such as P53 (p = 0.02) or Ki67 (p = 0.07). In the test set, the model produced similar results with a relative risk of 2.1 (p=0.029) for the high-risk group and shorter median time to recurrence (14.1 months versus not reached).&#x2028; Conclusions: Triple negative breast cancers show variable expression of proteins involved in DNA repair. Levels of four DNA repair proteins correlated significantly with recurrence free survival, and were used to develop a DNA repair profile model in a training set which was prognostic in a test set. DNA repair biomarker panels may be useful as prognostic or predictive indicators as well as suggest possible targets for novel therapies such as PARP inhibition. Further study of the model in another validation set with other clinical variables is warranted.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1064.

Influence of short-term fasting during the luteal phase of the estrous cycle on ovarian follicular development during the ensuing proestrus of ewes

Short-term fasting of mature ewes during diestrus results in increased serum concentrations of progesterone and a delayed pre-ovulatory surge release of LH. To determine if these changes in reproductive hormones influence subsequent follicular development, mature ewes observed in estrus were assigned randomly to control (n=10) or fasted (n=15) groups. Control ewes had ad libitum access to feed, whereas fasted ewes were not fed from day 7 through 11 of their estrous cycle. Daily blood samples were collected from control and fasted ewes throughout the fasting period. Fasting increased (P<0.001) serum concentrations of progesterone (4.4 ng/mL versus 2.7 ng/mL [+/-0.3]). On day 12, all ewes were treated with 10mg of PGF(2alpha) and fasted ewes were returned to ad libitum feed. Ovaries were collected from ewes (n=5 each group) at 0 and 72 h following PGF(2alpha) in control and 0, 72 and 96 h in fasted ewes. Ovaries were weighed and small (< or =2mm), medium (3-4mm), and large (> or =5mm) follicles were enumerated. Total numbers of follicles were less (P<0.001) in fasted than fed ewes (14.6 versus 30.2 [+/-2.2]) at 0 h, but did not differ (P=0.9) when numbers of follicles were compared at similar times before the anticipated LH surge (i.e., at 72 h versus 96 h in control and fasted ewes, respectively). Within follicular size class, numbers of small and medium follicles were decreased (P=0.04) at 0 h in fasted ewes. Numbers of large follicles did not differ (P=1.0) between groups. Although numbers of small and medium ovarian follicles in fasted ewes recovered by 96 h to values comparable to fed ewes at 72 h following PGF(2alpha), serum concentrations of estradiol 17beta (P=0.08) and FSH (P=0.06) tended to be decreased in fasted ewes before the anticipated surge release of LH. Pituitary content of LH and FSH also tended to be lower (P< or =0.09) at 96 h in fasted ewes than at 72 h in control ewes, but did not differ (P> or =0.4) at hour 0 following PGF(2alpha). Hypothalamic and stalk median eminence contents of GnRH were not influenced (P> or =0.2) by fasting at any time period. Fasting during the luteal phase perturbs gonadotropin secretion and may influence fertility by causing a delay in ovarian follicle development.

Effects of postpartum dietary fat and body condition score at parturition on plasma, adipose tissue, and milk fatty acid composition of lactating beef cows

Two experiments were conducted with lactating Angus x Gelbvieh beef cows to determine the effects of postpartum lipid supplementation, BCS at parturition, and day of lactation on fatty acid profiles in plasma, adipose tissue, and milk. In Exp. 1, 36 pri-miparous cows (488 +/- 10 kg of initial BW; 5.5 +/- 0.02 initial BCS) were given ad libitum access to hay and assigned randomly to a low-fat (control) supplement or supplements with cracked, high-linoleate safflower seeds (linoleate) or cracked, high-oleate safflower seeds (oleate) from d 3 to 90 of lactation. Diets were formulated to be isonitrogenous and isocaloric; safflower seed diets provided 5% of DMI as fat. Plasma and milk samples were collected on d 30, 60, and 90 of lactation. Adipose tissue biopsies were collected near the tail-head region of cows on d 45 and 90 of lactation. In Exp. 2, 3-yr-old cows achieving a BCS of 4 +/- 0.07 (479 +/- 36 kg of BW) or 6 +/- 0.07 (580 +/- 53 kg of BW) at parturition were used in a 2-yr experiment (n = 36/yr). Beginning 3 d postpartum through d 61 of lactation, cows were fed diets similar to those of Exp. 1. Adipose tissue and milk samples were collected on d 30 and 60, and plasma was collected on d 31 and 61 of lactation. Responses to postpartum dietary treatment were comparable in both experiments. Cows fed linoleate and oleate had greater (P < 0.001) total fatty acid concentrations in plasma than cows fed control. Except for 15:1, milk fatty acids with <18 carbons were greatest (P < or = 0.01) for cows fed control, whereas milk from cows fed linoleate had the greatest (P < or = 0.02) 18:1trans-11, 18:2n-6, and cis-9, trans-11 CLA. Milk from cows fed oleate had the greatest (P < 0.001) 18:1cis-9. In Exp. 1, total fatty acid concentrations in adipose tissue samples decreased at d 90 compared with d 45 of lactation, but the fatty acid profile of cow adipose tissue was not affected (P = 0.14 to 0.80) by dietary treatment. In Exp. 2, the percentage of cis-9, trans-11 CLA in adipose tissue of cows with a BCS of 6 decreased (P = 0.001) from d 30 to 60 of lactation. Plasma and milk fatty acid composition reflected alterations in postpartum diet. Less medium-chain fatty acids and more 18-carbon fatty acids in milk were indicative of reduced de novo fatty acid synthesis in the mammary gland of beef cows fed lipid supplements; however, the metabolic demands of lactation prevented the deposition of exogenously derived fatty acids in adipose tissue through d 90 of lactation.

Effects of feed restriction on reproductive and metabolic hormones in ewes

The goal of this study was to determine the effects of short-term feed withdrawal on reproductive and metabolic hormones during the luteal phase of the estrous cycle in mature ewes. Mature ewes observed in estrus were assigned randomly to control and fasted groups (n = 10 per group Trials 1 and 2). For Trials 1 and 2, control ewes had ad libitum access to feed, whereas fasted ewes were not fed from d 7 through 11 of their estrous cycle; on d 12, all ewes were treated with 10 mg of PGF2alpha, and fasted ewes were gvien ad libitum access to feed. For Trial 1, blood samples were collected daily through fasting and at 2-h intervals following PGF2alpha for 72 h. Serum concentrations of insulin (P < or = 0.002) and IGF-I (P < or = 0.01), but not GH (P > or = 0.60), were decreased during fasting compared with fed ewes. Serum concentrations of 29 (P = 0.02) and 34 kDa (P = 0.04) IGFBP were greater in fasted ewes at 96 h after initiation of fasting than in control ewes. Two control and four fasted ewes in Trial 1 did not exhibit a preovulatory surge release of LH by 72 h. Therefore, Trial 2 was conducted so that the timing of the LH surge could be predicted following the collection of blood samples at 2-h intervals for 112 h and then at 6-h intervals until 178 h following PGF2alpha administration and realimentation. The magnitude of the preovulatory LH surge in Trial 2 was decreased (P = 0.009) and delayed (P = 0.04), and serum concentrations of estradiol were diminished (P < or = 0.03) 12 h before the LH surge in fasted ewes. Ovulation rates were not influenced (P > or = 0.32) by fasting in Trials 1 and 2. Serum concentrations of progesterone in both Trials 1 and 2 were, however, greater (P < 0.001) in fasted than in control ewes. A third trial with ovariectomized ewes was conducted to determine whether the increased serum concentrations of progesterone observed in fasted ewes during Trials 1 and 2 were ovarian-derived. Ovariectomized ewes were implanted with progesterone-containing intravaginal implants and allotted to control (n = 5) or fasted (n = 5) treatment groups and fed as described for Trials 1 and 2. Similar to intact ewes, serum concentrations of progesterone were approximately twofold greater (P < 0.001) in fasted than in control implanted ovariectomized ewes. In summary, feed withdrawal for 5 d during the luteal phase of the estrous cycle increased serum concentrations of progesterone and evoked endocrine changes that could perturb the subsequent estrous cycle.

Effects of supplementation with high linoleic or oleic cracked safflower seeds on postpartum reproduction and calf performance of primiparous beef heifers

Primiparous Angus x Gelbvieh (n = 36) rotationally crossed beef cows (initial BW = 487.9 +/- 10.5 kg, body condition score = 5.5 +/- 0.02) were utilized to determine effects of supplemental safflower seeds high in linoleic (76% 18:2) or oleic (72% 18:1) acid on cow BW change, body condition score, milk production and composition, calf weight gain, cow serum metabolites, and metabolic hormones. On d 3 postpartum, cows were randomly assigned to one of three isonitrogenous dietary supplements with equal total quantity of TDN: corn-soybean control supplement (n = 12); high-linoleate safflower seeds (n = 12); or high-oleate safflower seeds (n = 12). Safflower-seed supplements were formulated to provide 5% DMI as fat. Supplements were individually fed from d 3 postpartum through 90 d postpartum. Cows had ad libitum access to native grass hay (7.8% CP), trace-mineralized salt, and water. Date of parturition was evenly distributed across treatments with all cows calving within 14 +/- 0.8 d. There were no differences (P = 0.65) in total OM intake among treatments. Although cow BW change did not differ (P = 0.33) by treatment, supplementation influenced cow body condition score (P = 0.02) with linoleate-supple-mented cows in higher (P = 0.005) condition overall than oleate-supplemented cows (5.1 +/- 0.06 vs 4.9 +/- 0.06). Twenty-four-hour milk production did not differ (P = 0.68) among treatments. Percentage milk fat was not different at d 30; however, at d 60 and d 90 percentage milk fat was greater (P ( 0.05) in control and oleate-supplemented cows than in linoleate-supplemented cows. Calf BW gains (P = 0.27) and adjusted 205-d weights (P = 0.48) were not affected by supplement treatment. Supplementation did not influence serum concentrations of glucose (P = 0.38), NEFA (P = 0.61), GH (P = 0.29), IGF-I (P = 0.81), insulin (P = 0.26), or IGF-I binding proteins (P > or = 0.11). Days to conception did not differ (P = 0.40) among treatments. Although overall productivity of the primiparous cows and their calves was not altered by safflower-seed supplementation, differential effects were noted between supplements. Oleate supplementation increased percentage milk fat at d 60, and cow body condition score was lower than in linoleate-supplemented cows. Linoleate-supplemented cows had greater body condition scores by 90 d postpartum than either corn-soybean- or oleatesupplemented cows.

Fos-like immunoreactivity in brain regions of domestic rams following exposure to rams or ewes

Limbic and basal forebrain-hypothalamic regions from male sheep differing in sexual performance were quantified for fos-like immunoreactivity. Rams classified as high-sexually performing (HP), low-sexually performing (LP), and male-oriented (MO) received noncontact sensory stimulation from either ewes in estrus (HP, n=5; LP, n=4; MO, n=4) or other males (HP, n=5; LP, n=4; MO, n=5) for a 4-h period on each of 3 consecutive days. Following exposure to stimulus animals on the third day, rams were euthanized and their brains were perfused with a 1% paraformaldehyde/1.5% glutaraldehyde solution and sections were analyzed for fos-like immunoreactivity. Brain regions analyzed were the medial amygdala (meAMY), medial preoptic area (mPOA), bed nucleus of the stria terminalis (BNST), and ventromedial hypothalamic nucleus (VMH). Fos-like immunoreactivity differed between groups in the mPOA and BNST but not in the meAMY or VMH. LP rams exposed to estrous ewes had more (P<.05) neurons staining positive for fos and fos-related antigens (FRA) in the mPOA and BNST than LP rams exposed to other rams or MO rams exposed to either estrous ewes or other rams. Numbers of neurons staining positive for FRA in the mPOA and BNST of LP rams exposed to estrous ewes, however, were not different (P>.05) from HP rams exposed to either estrous ewes or other rams. The similar fos-like immunoreactivity in areas important for the display of sexual behavior in HP and LP rams may reflect similar sensory input in these two groups of rams; however, LP rams, in contrast to HP rams, do not appear to respond similarly to the same sensory stimulus.

Low-sexually performing rams but not male-oriented rams can be discriminated by cell size in the amygdala and preoptic area: a morphometric study

Brain regions of male sheep behaviorally classified as high-sexually performing (n=10), low-sexually performing (n=8) or male-oriented (n=9) were examined to determine if differences in reproductive behavior were associated with differences in density or sizes of neurons. High-sexually performing rams actively mounted estrous ewes, low-sexually performing rams failed to mount or had long latencies to mounting estrous ewes, and male-oriented rams mounted other rams in preference to ewes in estrus. Cell densities and sizes were quantified in Nissl stained sections through the medial amygdala (meAMY), preoptic area (POA), bed nucleus of the stria terminalis (BNST), ventromedial hypothalamic nucleus (VMH), lateral geniculate nucleus (LG) and medial geniculate nucleus (MG). Multivariate discriminant analysis based on soma sizes within nuclei of known importance for reproductive behavior and/or gonadotropin release (meAMY, POA, BNST and VMH) discriminated (Wilks Lambda P<0.05) low-performing rams from high-performing and male-oriented rams, but did not discriminate (Wilks Lambda P=0.14) between high-performing and male-oriented rams. Cell size in the parvocellular and magnocellular layers of the LG along with cells of the MG, structures without a specific role in reproduction, did not discriminate any of the three behaviorally defined groups of rams (Wilks Lambda P=0.57). Density of cells present in structures important for the display of reproductive behavior (POA, meAMY, BNST) and/or gonadotropin release (POA, VMH) had no discriminating power nor did density of cells in structures important for the processing of visual (LG) or auditory (MG) stimuli. In conclusion, significant differences in sizes of cells located within nuclei that are specifically important for the display of male reproductive behavior were found in low-sexually performing rams compared to high-sexually performing and male-oriented rams. These differences may result from neuron development in utero or occur later as a consequence of endocrine factors or behavioral experience. Neuronal cell size is a critical variable that determines excitability to synaptic inputs because cell surface area varies exponentially with cell diameter. Relatively small differences in neuron diameter could relate to functionally important differences in neuronal excitability.

Behavior and endocrine changes in high-performing, low-performing, and male-oriented domestic rams following exposure to rams and ewes in estrus when copulation is precluded

High-performing, low-performing, and male-oriented rams were used to investigate behavior and neuroendocrine correlates of sexual interest and discrimination. Treatment consisted of visual and olfactory contact with stimulus animals through a woven wire fence, which inhibited copulation (either ewes in estrus or other rams), for 4 h on each of three consecutive days. Before exposure to stimulus animals on d 1 and during the final 1 h of exposure on d 2, blood samples were collected every 15 min for 1 h to determine concentrations of LH and testosterone. During exposure to stimulus animals, rams were continuously observed and investigatory behaviors were recorded. There was no day effect for any behavior. Groups of rams differed (P < .05) in amounts of behaviors exhibited, but behaviors were not influenced by sex of stimulus animals. High-performing rams exhibited more (P < .05) investigatory behaviors toward stimulus animals than low-performing or male-oriented rams. Plasma concentrations of LH increased (P < .05) in high-performing rams following exposure to estrous ewes, but not following exposure to rams. In low-performing and male-orientated rams, concentrations of LH were unchanged regardless of sex of the stimulus animal. Change in plasma concentrations of testosterone from pre- to posttreatment did not differ between high-performing, low-performing, and male-oriented rams. However, low-performing rams exhibited an increase (P < .05) in plasma concentrations of testosterone following exposure to rams. In conclusion, high-performing rams exhibit a high degree of investigatory behaviors toward estrous ewes and other rams. High-performing rams seem to discriminate sex of stimulus animals and exhibit a neuroendocrine response (i.e., increased plasma LH) only when exposed to ewes in estrus. The sensory signals provided by estrous females are either not detected by low-performing or male-oriented rams or are not sufficiently provocative to elicit further investigation by these rams.

Effects of porcine relaxin on induced parturition in beef heifers

Two-year-old crossbred beef heifers were used to test the effects of porcine relaxin (pRelaxin) alone, or in combination with dexamethasone, on the induction of parturition, the incidence of dystocia, and retained placentas. Effects of treatment on pelvic area, postpartum interval, milk production, colostrum quality, calf birth weight, calf vigor, and calf performance were also evaluated. On Day 275 of gestation, heifers from two fetal-sire groups were randomly assigned to one of four groups in a 2 x 2 factorial design and received; no treatment (controls, n = 19), 20 mg of dexamethasone intramuscularly (im) (n = 22), 5 mg of pRelaxin (3,000 U/mg) im (n = 19), or 20 mg of dexamethasone plus 5 mg of pRelaxin (n = 17). Length of gestation (in days) was less (P < 0.05) in heifers treated with dexamethasone (279.8 +/- 1.0) than in controls (286.6 +/- 0.9), but was not influenced (P > 0.05) by treatment with pRelaxin. The incidence of retained placentas in heifers treated only with dexamethasone (27.3%) was not reduced by concomitant treatment with pRelaxin (35.3%). Retained placentas were not observed in any control heifers and in only one heifer (5.2%) treated solely with pRelaxin. Ease of calving (1 = unassisted, 5 = abnormal presentation) was not influenced by treatment (P > 0.05), even though birth weights (in kilograms) of calves from heifers treated with dexamethasone (36.4 +/- 0.8) were less (P < .01) than those of calves from nondexa-methasone-treated heifers (39.2 +/- 0.8). Dexamethasone tended to reduce (P < 0.07) calf vigor (1 = healthy and strong, 5 = dead on arrival; 1.48 +/- 0.11 vs. 1.18 +/- 0.11), but was not (P > 0.05) influenced by pRelaxin. The duration of the postpartum anestrous interval (73.1 +/- 1.8 d across groups) and pelvic areas following treatment and parturition were not influenced (P > 0.05) by dexamethasone or pRelaxin. Although determinants of colostrum quality (P < 0.01) and quantity (P < 0.08) of milk produced were influenced by dexamethasone, adjusted 205-d weights of calves did not differ (P > 0.05) among groups. In conclusion, treatment with pRelaxin alone failed to induce parturition or, when combined with dexamethasone, to reduce the incidence of retained placentas.

Pregnancy determination by use of pregnancy-specific protein B radioimmunoassay in llamas

Blood samples were obtained from each of 30 llamas: 22 females that had been exposed to a male and were assumed to be pregnant (gestational stage, 2 to 244 days), 1 female that had not been exposed to a male, 3 sexually intact males, 1 castrated male, and 3 females with congenital reproductive anomalies. Serum was tested for the presence of pregnancy-specific protein B, using a radioimmunoassay that accurately detected pregnancy in cattle, sheep, and other ruminants. Pregnancy-specific protein B was not detected in the serum of the 30 llamas. On the basis of our results, the radioimmunoassay for pregnancy-specific protein B cannot be used in llamas for detection of pregnancy.

Fertility of bull semen packaged in .25- and .5-milliliter french straws

The fertility of bull semen packaged in .25- and .5-mL french straws was compared. One ejaculate from each of five Holstein bulls was split, extended to 10 x 10(6) spermatozoa/inseminate dose in whole homogenized milk, packaged in .25- and .5-mL french straws, frozen in liquid nitrogen (LN) vapor, and stored in LN. Semen was thawed at 37 degrees C for 30 s. Synchronized heifers (n = 1,360) were inseminated (during a 12-mo period) with semen packaged in either a .25- or .5-mL french straw. Blood was collected on the day of insemination and the serum was assayed for progesterone. Heifers with blood progesterone levels of > 1 ng/mL were eliminated from the data. Blood was collected at 30 to 45 d after insemination and the serum was assayed for the presence of bovine pregnancy-specific protein B (bPSPB) by RIA to determine pregnancy. Conception was 63.6 and 62.0% (P = .55) for semen packaged in the .25- and .5-mL french straws, respectively. There was neither a bull x packaging unit interaction (P = .49) nor a day of insemination x packaging unit interaction (P = .87). Conception among bulls ranged from 57.1 to 68.0% (P = .19). No evidence was found that meteorological factors influenced conception. Under the conditions of this experiment, semen packaged in the .25- and .5-mL french straw had similar fertility.

Embryonic loss from 30 to 60 days post breeding and the effect of palpation per rectum on pregnancy

This study was conducted over a 12-mo period to determine the rate of bovine embryo death between 30 and 60 d of gestation. In addition, palpation per rectum as a means of pregnancy detection was evaluated as a possible cause of embryo death. Estrus was synchronized in Holstein heifers (n = 1358), weighing > or = 385 kg, with a single intramuscular injection of 25 mg prostaglandin F(2alpha). Estrus was primarily detected by the absence of paint marks on the tailhead. The heifers were artificially inseminated with semen from 5 Holstein sires. Blood was collected between 30 and 45 d after breeding, and sera were evaluated for the presence of bovine pregnancy-specific protein B (bPSPB) by RIA to determine pregnancy. Palpation for fetal membrane slip was conducted by an experienced technician in approximately one-half of the inseminated heifers. To determine embryonic survival, a second blood sample was collected at approximately 60 d from 862 heifers that were determined to be pregnant at the first blood sampling. Embryonic loss averaged 5.3% during the interval between the initial detection of pregnancy at 30 to 45 d and the subsequent detection of pregnancy at 60 d of gestation. Embryo loss in heifers that were palpated was 6.5% compared with that of 4.3% in the control heifers (X(2): P = 0.145). These findings establish that there was substantial loss of embryos between 30 and 60 d post breeding but that embryo loss was not affected by palpation per rectum.

Hypothalamic and hypophyseal receptors for estradiol in high and low sexually performing rams

Rams, characterized over a 3-year period as being high (n = 8) or low (n = 10) sexual performers, were euthanized to determine if differences in sexual behavior were associated with differences in hypophyseal and hypothalamic receptors for estradiol. Rams were exposed to estrous ewes and courtship behavior was recorded for 5 hr prior to tissue collection. Blood samples for determination of serum concentrations of luteinizing hormone (LH) were collected every 15 min during the behavior testing period. Hourly blood samples were analyzed for serum concentrations of estradiol (E) and testosterone (T). Rams characterized as high (HP) or low (LP) sexual performers had similar LH profiles; there were no differences noted in basal concentration, number of pulses, or pulse amplitude of LH. There were no differences in serum concentrations of T or E during the behavior testing period between HP and LP rams. Unoccupied receptors for E (moles E bound x 10(-15)) in the stalk-median eminence (SME) (P < 0.05) in HP rams (15.1 +/- 3.1) were greater than those in LP rams (4.6 +/- 1.9). Occupied receptors for E (moles E bound x 10(-15)) in the preoptic area (POA) (P < 0.1) in HP rams (6.0 +/- 0.8) tended to be greater than those in the LP rams (3.8 +/- 0.8). The proportion of total E receptors (occupied+unoccupied) in the POA that were occupied was greater (P < 0.05; 0.41 +/- 0.03 vs 0.23 +/- 0.04) for HP than for LP rams. In contrast, HP rams had less (P < 0.05) occupied E receptors (moles E bound x 10(-15)) in the anterior pituitary gland (AP) than LP rams (152.0 +/- 38.5 vs 337.3 +/- 51.7). The proportion (%) of E receptors that were occupied in the AP in HP rams also tended to be less (P < 0.06) than that in LP rams (8 +/- 2 vs 14 +/- 1). No differences were detected in occupied or unoccupied E receptors in the medial basal hypothalamus, medial amygdala, or stalk-median eminence. In conclusion, differences in occupied receptors for E in the POA and the AP, and unoccupied receptors for E in the SME, were associated with differences in ram sexual behavior.

Effects of season and estradiol on concentrations of histamine within discrete brain regions of ovariectomized ewes

Histamine has been implicated as a neuromodulator of secretion of gonadotropins in several species. Concentrations of histamine were analyzed within discrete brain regions and endocrine tissues to help determine whether this amine has the potential to exert a similar function in ewes expected to have dramatically different serum concentrations of LH. Following collection of blood samples at 12-min intervals for 4-hr, ovariectomized (OVX) and OVX-estradiol treated (OVX-E) ewes were slaughtered during the breeding and anestrous seasons (five animals/group). Concentrations of LH were depressed by treatment with estradiol (E; P < .01), but to a greater extent (P < .05) during the anestrous season compared to the breeding season. Concentrations of histamine in tissues (ng/mg) differed (P < .01) between the breeding and anestrous seasons, in the medial thalamus (39.2 +/- 14.1 vs 109.9 +/- 13.0), posterior pituitary gland (247.6 +/- 50.7 vs 23.0 +/- 9.1) and midbrain tegmentum (10.4 +/- 5.6 vs 50.7 +/- 3.9). Estradiol containing implants decreased (P < .05) concentrations of histamine in the midbrain tegmentum (20.3 +/- 7.1 vs 37.7 +/- 7.8) and posterior pituitary gland (87.3 +/- 24.0 vs 258.2 +2- 67.5) compared to non-estradiol treated controls. Histamine concentrations in the pineal and anterior pituitary glands and brain regions; stalk-median eminence, medial basal hypothalamus, preoptic area, cerebellum, parietal neocortex, were not (P > .05) affected solely by either season or E. An interaction between effects of season and estradiol on concentrations of histamine occurred (P < .05) in the posterior pituitary gland and the preoptic area.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration of GnRH at estrus influences pregnancy rates, serum concentrations of LH, FSH, estradiol-17 beta, pregnancy-specific protein B, and progesterone, proportion of luteal cell types, and in vitro production of progesterone in dairy cows

Four experiments were conducted to examine effects of GnRH administered at estrus on various reproductive characteristics in repeat-breeding dairy cows (eligible for third service). In Exp. 1, cows (n = 8 per group) received (i.m.) either saline or 50, 100, or 250 micrograms of GnRH at 12 h after onset of estrus. There was a positive linear (P < .05) effect of dose on concentrations of LH, but not of FSH, in serum at 2 h after the injection. Concentrations of progesterone (P4) were higher (P = .10) through 16 d after estrus in nonpregnant cows that returned to estrus 18 to 24 d after GnRH treatment than in nonpregnant cows given saline. Likewise, among cows with elevated concentrations of P4 through 30 d after estrus (diagnosed pregnant by increased concentrations of pregnancy-specific protein B; PSPB), P4 was higher (P = .10) in those given GnRH than in those given saline. In Exp. 2, concentrations of LH, FSH, and estradiol-17 beta (E2) were similar among 12 cows during the periestrual period before they received (i.m.) 100 micrograms of GnRH or saline at estrus. Concentrations of P4 after estrus were increased 2 d earlier (P < .05) in GnRH- than in saline-treated cows. Among cows with elevated concentrations of P4 and PSPB through 40 d after AI, P4 was higher (P < .05) in those given GnRH than in those given saline. In Exp. 1 and 2, a greater proportion (43 vs 14%; P = .07) of cows given GnRH was pregnant 42 to 56 d after estrus than of those given saline, but calving rate was similar (27 vs 14%). In Exp. 3, average number of LH pulses per 8 h was similar between saline- and GnRH-treated cows on d 1, 3, and 8, but overall concentrations of LH were reduced (P < .05) in GnRH-treated cows. Concentrations and number of pulses of FSH were increased (P < .05) on d 8 after treatment with GnRH. Concentrations of P4 were increased earlier (P < .05) after estrus in GnRH-treated (69 +/- 12 h) than in saline-treated cows (126 +/- 12 h), with higher (P < .05) concentrations of P4 on d 4 to 8. In Exp. 4, eight cows received either 100 micrograms of GnRH or saline at 12 h after onset of estrus (d 0) in a cross-over design.(ABSTRACT TRUNCATED AT 400 WORDS)

Gonadotropin-releasing hormone overrides the negative effect of reduced dietary energy on gonadotropin synthesis and secretion in ewes

During prolonged periods of reduced dietary energy, there is a reduction in secretion of LH in females. To test the hypothesis that decreased secretion of LH is due to reduced secretion of GnRH, 18 ovariectomized ewes were fed either a low-energy diet (LOW, 60% of the National Research Council recommendations, n = 12) or a normal diet, (control, n = 6), for 127 days. Each ewe received basal levels (approximately 5 pg/ml) of estradiol via sc Silastic implants. After 127 days, serum concentrations of FSH and LH were reduced (P less than 0.05) by 63% and 77%, respectively in LOW ewes compared to control ewes. Pituitary concentrations of FSH and LH in LOW ewes also were reduced by 56% and 80%, respectively. Compared to levels in control ewes, concentrations of messenger RNAs for alpha-, FSH beta-, and LH beta-subunits were reduced by 75%, 76%, and 91%, respectively. Pulsatile administration of GnRH (250 ng/2 h) for three weeks to LOW ewes restored each of the parameters to levels not different from those in controls. By the end of the study, serum concentrations of GH in all LOW animals had risen dramatically, but not in control ewes. Therefore, it appears that exogenous GnRH is capable of restoring synthesis and secretion of gonadotropins in ewes receiving low-energy diets. These results provide support for the hypothesis that reduced dietary energy results in decreased secretion of GnRH.

Secretion of platelet-activating factor by periovulatory ovine follicles

Secretion of platelet-activating factor (PAF) in vitro by ovine follicles and ovarian interstitium obtained at various times before, during and after the endogenous preovulatory surge of luteinizing hormone (LH) and ovulation was quantified by radioimmunoassay. Release of PAF by the preovulatory follicle increased within 2 h after initiation of the surge of LH. Capacity for secretion of PAF was greatest at the time of ovulation, then declined thereafter. Production of PAF by ovarian interstitium throughout the periovulatory period was relatively low and did not change with time. It appears that PAF could act as an intrafollicular mediator in the mechanisms of ovulation and(or) luteinization.

Use of non-human plasma for in vitro cultivation and antimalarial drug susceptibility testing of Plasmodium falciparum

Viability, growth rate, and chemotherapeutic susceptibility of the CDC/Indochina III, CDC/Sierra Leone I, and FCR-3 (Subline F-86) isolates of Plasmodium falciparum grown continuously in RPMI 1640 medium supplemented with goat, horse, porcine, bovine, or ovine plasma were evaluated. Results were compared to those obtained from parallel cultures maintained in medium supplemented with non-immune human plasma. Only media supplemented with goat or horse plasma supported significant continuous multiplication of the isolates. Medium supplemented with either ovine or porcine plasma supported continuous multiplication of the CDC/Indochina III isolate, but not the FCR-3 isolate. Medium supplemented with bovine plasma did not support continuous growth of any of the isolates tested. The light microscopic appearance of the isolates during and after continuous culture in medium supplemented with either goat or horse plasma was identical to that of the control parasites maintained in medium supplemented with human plasma. There were no statistically significant differences in the susceptibility to antimalarial drugs of the culture lines maintained in medium supplemented with either human or goat plasma.