Search for low-mass weakly interacting massive particles using voltage-assisted calorimetric ionization detection in the SuperCDMS experiment.

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c2.

Identification of transgenic mice by PCR analysis of saliva.

As an alternative to surgically obtaining samples (e.g., tail or tissue biopsy, toe dock, or blood sampling) from weanling mice to screen for transgene integration or other genetic monitoring procedures, we offer a simpler, nonsurgical method. A small amount of saliva, obtained from weanling mice by oral wash using a plastic pipet tip, contains enough oral epithelial cells and lymphocytes to yield sufficient DNA for nested primer polymerase chain reaction (PCR) analysis. The procedure can be repeated many times with minimal stress to the animal, in contrast to tissue biopsy procedures such as tail cutting. Sample analysis is rapid and straightforward; saliva is applied to sample collection paper and then purified using a solid phase DNA purification system. The paper, containing purified DNA, is added directly to PCR cocktail for the first round of amplification. For weanling mice, in the second round of amplification, a small amount of product from the first round is removed and added to PCR cocktail containing the second set of primers. With adult mice, an adequate volume of saliva may be obtained (dependent upon the sensitivity of the particular reaction) to eliminate the need for second-round amplification with nested primers. This technique is reliable, does not require organic solvents, and is more humane than protocols currently in use. Furthermore, this technique could replace hundreds of thousands of surgical biopsies on rodents annually, which are performed for both transgene determination and genetic monitoring procedures.

Antibiotic Prophylaxis Regimens in Trauma and Orthopaedic Surgery: Are We Providing Adequate Cover Against Colonizing Organisms?

UNLABELLED: Trauma, elective orthopaedics, and an aging population will result in an increasing health burden and work load. The move to surgical podiatrists in the National Health Service within the United Kingdom will shift the surgical workload away from orthopaedic surgeons. A devastating complication of foot and ankle surgery is postoperative infection. While postoperative infection is multifactorial in etiology, concomitant diabetes mellitus increases the general risk of trauma and orthopaedic surgical site infections up to 8-fold. We therefore undertook a prospective study of our unit antibiotic prophylaxis regimes. Fifty patients participated. Swabs were obtained using aseptic technique from the plantar aspect of the feet, between the toes, and subsequently cultured on agar plates. Specimens were then incubated for 48 hours before being exposed to antibiotic plates. Cultured organisms were classified as susceptible to an antibiotic regimen if susceptibility to cefuroxime, or susceptibility to either drug of the flucloxacillin/gentamicin combination, was demonstrated. Statistical analysis e was performed. A P value <.05 was considered significant. Fifty patients were recruited, 26 (52%) were male. Mean age of 53 ± 19.4 years. The cohort included 15 diabetic, of which 11 (73.3%) insulin-dependent, and 35 nondiabetic patients. Comparing flucloxacillin/gentamicin against cefuroxime overall, susceptibility was noted in 84% and 70%, respectively (P = .096). Resistance to cefuroxime was significantly higher in diabetics than in nondiabetics (53% vs 25%, P = .046). The same pattern was observed for the flucloxacillin/gentamicin regimen (33% vs 9%, P = .049). While both regimens are active against colonizing organisms in this prospective observational study, flucloxacillin and gentamicin provide greater coverage overall. We have demonstrated that the use of flucloxacillin/gentamicin provides better coverage against commensal bacterial flora compared with cefuroxime alone. This is of even greater importance in the case of the specific high-risk subgroups, such as diabetic patients. LEVELS OF EVIDENCE: Level IV: Case Series.

Effects of cessation of smoking on serum lipids and high density lipoprotein-cholesterol.

This study examined the effect of cessation of smoking on serum lipid and lipoprotein levels. Twenty-six females who smoked a minimum of 20 cigarettes per day for the past 5 years served as volunteers. Twelve subjects abstained from smoking for a period of 60 days (ex-smokers). Six stopped smoking for 30 days then resumed smoking for an additional 30 days (re-smokers). Eight subjects continued to smoke for the entire 60 days (smokers). Additionally, 10 females who had never smoked served as non-smoking controls (non-smokers). Pre-cessation HDL-C levels for all smoker groups were 15-20% (P less than 0.05) below those of non-smokers. By day 30 of cessation HDL-C levels of ex-smokers and re-smokers significantly increased by 5.7 and 10.5 mg/dl, respectively, and were significantly higher than those of smokers. At day 60, HDL-C of ex-smokers increased another 6.8 mg/dl to 63.9 mg/dl while levels of re-smokers returned to pre-cessation levels (50.7 mg/dl). The findings of this study suggest that low levels of HDL-C associated with smoking in females do not appear to be cumulative and can be reversed in as little as 30 days.

Changes in progesterone and oestrogen receptor mRNA and protein and oxytocin receptors in endometrium of ewes after intrauterine injection of ovine trophoblast interferon.

This study determined whether twice-daily intrauterine injections of ovine conceptus secretory proteins (oCSP) containing type-I trophoblast interferon (25 micrograms/uterine horn) from day 11 to day 15 post-oestrus (oestrus = day 0) could alter the binding capacities of endometrial receptors for oxytocin, progesterone and oestrogen in cyclic ewes when compared with control ewes receiving serum protein (SP) injections. Injections of oCSP on days 11-15 post-oestrus decreased concentrations of oestrogen receptors (P < 0.06), oestrogen receptor mRNA (P < 0.05) and progesterone receptors (P < 0.08) in endometrium on day 16 when compared with SP-infused control ewes, which were undergoing corpus luteum regression on days 14-16. Injection of oCSP also decreased the number (P < 0.10) and affinity (P < 0.06) of oxytocin receptors. Inositol phosphate formation induced in the endometrium on day 16 by 100 nM oxytocin in vitro was highly correlated with the concentration (r > or = 0.93, P < 0.001) and Kd (r = -0.91, P < 0.01) of oxytocin receptors in SP-infused ewes, but was not as highly correlated with concentration (r < or = 0.83, P < 0.06) and Kd (r < or = 0.40, P > 0.40) of oxytocin receptors in oCSP-infused ewes. This indicates that oCSP disrupted the relationship between oxytocin receptor binding and oxytocin-induced activation of its second messenger system. These results indicate that antiluteolytic type-I trophoblast interferon may prevent oxytocin-induced luteolytic pulsatile secretion of prostaglandin F2 alpha during maternal recognition of pregnancy in sheep, by reducing the synthesis and affinity of endometrial oxytocin receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Cessation from cigarette smoking: changes in body weight, body composition, resting metabolism, and energy consumption.

This study examined the effect of cessation from smoking on body weight, body fat, resting metabolic rate (RMR), and caloric consumption. Twenty-six women aged 25 to 45 years (mean, 37.2 +/- 4.7) who smoked 20 or more cigarettes per day for the past 5 years served as volunteers. Twelve subjects abstained from smoking for a period of 60 days (EXSMOKERS). Six stopped smoking for 30 days, then resumed the habit for an additional 30 days (RESMOKERS). Eight subjects continued to smoke for the entire 60 days (SMOKERS). Additionally, 10 women who had never smoked served as nonsmoking controls (NONSMOKERS). Body weight was recorded weekly and body fat was calculated from body density as determined by hydrostatic weighing. RMR was assessed by open-circuit spirometry. Caloric intake was obtained from 3-day food records using a computerized nutrient data base. Group means for body weight, body fat, RMR, and caloric intake were compared using a repeated measures ANOVA with a Scheffe post hoc at day 0 (baseline), day 30, and day 60 of cessation from smoking. NONSMOKERS weighed significantly (P less than .05) more, but were no fatter than all smoker groups at day 0. Body weight significantly increased by 1.8 kg (EXSMOKERS) and 2.1 kg (RESMOKERS) at day 30 of cessation. By day 60 EXSMOKERS' body weight had increased an additional 1.8 kg to 61.6 +/- 6.4 kg, while return to smoking (RESMOKERS) resulted in a 3.1 kg loss of body weight to 57.9 +/- 7.9 kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of worksite environmental tobacco smoke on serum lipoprotein profiles of female nonsmokers.

The purpose of this study was to examine the influence of environmental tobacco smoke (ETS) in the workplace on high-density lipoprotein cholesterol (HDL-C), HDL-C subfractions, and apolipoprotein (apo) A-I and apo B in female workers. Premenopausal women free from factors known to influence HDL-C (cigarette smoking, vigorous physical exercise, etc) who were not taking oral contraceptives, were moderate consumers of alcohol, caffeine, and dietary fat, and were between the ages of 21 and 50 years participated in one of two groups: (1) nonsmokers who had never smoked cigarettes and were generally free from ETS exposure (nonsmokers), and (2) nonsmokers who had never smoked but were subjected to concentrated doses of ETS at least 6 hours per day, 4 days per week, for at least 6 consecutive months (ETS-exposed). A third group consisting of current cigarette smokers who smoked a minimum of 20 cigarettes per day for at least the past 5 consecutive years served as smoking control (smokers). Subjects were matched by group as closely as possible with regard to criteria that can influence blood lipoprotein levels. Participants were solicited from taverns and restaurants where they were employed. It was hypothesized that individuals chronically exposed to ETS would demonstrate unfavorable lipoprotein profiles. Results showed that HDL-C, HDL2, and apo A-I were significantly (P < .05) depressed for ETS-exposed and smokers as compared with nonsmokers. Values for ETS-exposed were not different from those for smokers. Total cholesterol, triglycerides, HDL3, and apo B did not differ among the three groups. It was concluded that excessive exposure to ETS in female workers can have deleterious effects on HDL-C, HDL2, and apo A-I in nonsmokers that are similar to effects observed in cigarette smokers. It is possible that these effects increase coronary artery disease (CAD) risk.

VO(2) kinetics and the O(2) deficit in heavy exercise.

The purpose of this study was to examine a new method for calculating the O(2) deficit that considered the O(2) uptake (VO(2)) kinetics during exercise as two separate phases in light of previous research in which it was shown that the traditional O(2) deficit calculation overestimated the recovery O(2) consumption (ROC). Eight subjects completed exercise transitions between unloaded cycling and 25% (heavy, H) or 50% (very heavy, VH) of the difference between the lactic acid threshold (LAT) and peak VO(2) for 8 min. The O(2) deficit, calculated in the traditional manner, was significantly greater than the measured ROC for both above-LAT exercises: 4.03 +/- 1.01 vs. 2.63 +/- 0.80 (SD) liters for VH and 2.36 +/- 0.91 vs. 1.74 +/- 0.63 liters for H for the O(2) deficit vs. ROC (P < 0.05). When the kinetics were viewed as two separate components with independent onsets, the calculated O(2) deficit (2.89 +/- 0.79 and 1.71 +/- 0.70 liters for VH and H, respectively) was not different from the measured ROC (P < 0.05). Subjects also performed the same work rate for only 3 min. These data, from bouts terminated before the slow component could contribute appreciably to the overall VO(2) response, show that the O(2) requirement during the transition is less than the final steady state for the work rate, as evidenced by symmetry between the O(2) deficit and ROC. This new method of calculating the O(2) deficit more closely reflects the expected O(2) deficit-ROC relationship (i.e., ROC >/= O(2) deficit). Therefore, estimation of the O(2) deficit during heavy exercise transitions should consider the slow component of VO(2) as an additional deficit component with delayed onset.

VO2 and heart rate kinetics in cycling: transitions from an elevated baseline.

The purpose of this study was to examine oxygen consumption (VO2) and heart rate kinetics during moderate and repeated bouts of heavy square-wave cycling from an exercising baseline. Eight healthy, male volunteers performed square-wave bouts of leg ergometry above and below the gas exchange threshold separated by recovery cycling at 35% VO2 peak. VO2 and heart rate kinetics were modeled, after removal of phase I data by use of a biphasic on-kinetics and monoexponential off-kinetics model. Fingertip capillary blood was sampled 45 s before each transition for base excess, HCO and lactate concentration, and pH. Base excess and HCO concentration were significantly lower, whereas lactate concentration and pH were not different before the second bout. The results confirm earlier reports of a smaller mean response time in the second heavy bout. This was the result of a significantly greater fast-component amplitude and smaller slow-component amplitude with invariant fast-component time constant. A role for local oxygen delivery limitation in heavy exercise transitions with unloaded but not moderate baselines is presented.

Smoking-induced elevations in blood carboxyhaemoglobin levels. Effect on maximal oxygen uptake.

Many people engage in physical activity to reduce their cardiovascular risk associated with smoking. These people should be made aware of the metabolic and cardiorespiratory changes induced by chronic and acute smoking and, in particular, the exercise ramifications of increased levels of blood carbon monoxide (CO). Smoking-induced elevations in the CO content of the blood can reduce exercise tolerance and maximal aerobic capacity. Smoking also increases the reliance upon glycolytic metabolism during exercise. Together, these factors contribute to earlier fatigue in smokers compared with nonsmokers who exercise. Similar effects upon exercise tolerance are noted in those who inhale environmental tobacco smoke.

Dietary status of elite female high school gymnasts: inadequacy of vitamin and mineral intake.

In general, the diets of these athletes appeared to be nutritionally inadequate. Diets were judged to be inadequate for vitamins B-6, folic acid, calcium, iron, zinc, and magnesium in 30% to 60% of gymnasts studied. Several reasons seem to make this population somewhat more vulnerable: (a) the desire to be light, lean, and aesthetically appealing; (b) the anaerobic nature of their sport, which does not lend itself to excessive levels of energy expenditure; and (c) the fact that these athletes are teenagers, subscribing all too often to typical teenage diets. It seems clear that this is a population which could benefit from nutrition counseling.

VO(2) slow component: to model or not to model?

PURPOSE: The purpose of this study was to compare several techniques often used in the literature for measuring the amplitude of the slow component of oxygen uptake kinetics. METHODS: Eight healthy male volunteer cyclists performed two identical bouts of square wave cycle ergometry, from a VO(2) of 60% of the lactic acid threshold (LAT) to 30% of the difference between LAT and VO(2) peak. Predetermined intervals (3--6 and 3--10 min) were chosen to reflect those often used in the literature, namely 3-6 min and 3 min to the end of exercise. Several procedures were used to estimate the 3, 6, and 10-min VO(2) values (20-s averaging, 60-s averaging, and mono-exponential modeling). These were compared with the modeled slow component amplitude using a two-phase model with independent time delays: VO(2)(t) = B VO(2) + A(1)(1 -- e(-(t-TD1)/tau(1)) + A(2)(1 -- e(-(t-TD2)/tau(2)). CONCLUSIONS: The results showed a significant underestimation for all methods of slow component amplitude estimation (P < 0.05) when compared with the actual (modeled) amplitude. In so far as research on oxygen uptake kinetics is used to understand the underlying physiology, it is imperative that the components of the kinetics be determined accurately. The use of a predetermined time frame for estimation of the amplitude of the slow component is not supported by this study. Future investigations should consider these results and make every effort to model the underlying response.

Leg electromyography and the VO2-power relationship during bicycle ergometry.

PURPOSE: The relationship between oxygen consumption and power is not linear. The purpose of this investigation was to examine the nature of the relationship and the cause of the nonlinearity. METHODS: Eight male cyclists (60.5 +/- 3.8 mL O2.min-1.kg(-1) VO2 peak) completed an incremental exercise test (1 W.5 s(-1)) to exhaustion. VO2 was measured every breath, and rmsEMG was recorded continuously over the belly of vastus lateralis, biceps femoris, and lateral gastrocnemius. RESULTS: VO2 is a linear function of power in moderate exercise; the slope of the linear portion was approximately 9.7 mL O2.min(-1).W(-1), which is consistent with the steady state gain for moderate exercise. Beyond this initial break from linearity, the VO2.W(-1) plot demonstrates a second break that is not different from the point of respiratory compensation (break in VE.VCO2(-1)). These breaks were coincident with increased neuromuscular activity (1st break: 194 +/- 27 W for VO2, 191 +/- 25 W for vastus lateralis; 2nd break: 262 +/- 34 W for VO2, 258 +/- 27 W for vastus lateralis) and corresponded to approximately 58% VO2 peak for the first and 75% VO2 peak for the second break. CONCLUSIONS: VO2 is not a linear function of power. During an incremental test, neuromuscular activity and VO2 increase more rapidly in heavy exercise. Both VO2 and neuromuscular activity exhibit a second break at very high power output, which may mark an upper limit for sustainable exercise.

Muscular development and lean body weight in body builders and weight lifters.

The extent of extreme muscular development in 39 males identified as body builders (N = 18), power weight lifters (N = 13), and Olympic weight lifters (N = 8) were studied. Body composition and anthropometric data, including calculations of pre-excess muscle body weight (scale weight minus excess muscle) were obtained. The lean body weight and percent fats of the subjects were: body builders = 74.6 kg, 9.3%; power weight lifters = 73.3 kg, 9.1%; and Olympic weight lifters = 68.2 kg, 10.8%. No group differences were present in frame size, percent fat, lean body weight, skinfolds, and diameter measurements. The only group differences were for the shoulders, chest, biceps relaxed and flexed, and forearm girths. In each case the body builders were larger. Calculations of excess muscle by the Behnke method revealed that the body builders had 15.6 kg excess muscle, power weight lifters 14.8 kg, and Olympic weight lifters 13.1 kg. Somatographic comparisons revealed only slight differences between the groups, while differences with reference man were substantial.

Acute effects of resistance exercise on parameters of lipoprotein metabolism.

Ten healthy, trained males (25.4 +/- 3.1 yr) were studied before and after 90 min of resistance exercise to determine the acute effects of high volume (HV) and low volume (LV) sessions on alterations in lipid and lipoprotein concentrations as well as the activity of lecithin: cholesterol acyltransferase (LCAT). The HV session involved the use of 8-12 repetition maximum (RM) loads performed to exhaustion with 60 s rest intervals between sets, while the LV session involved the use of 1-5RM loads with 3 min rest intervals between sets. Fasting blood samples were drawn from an antecubital vein immediately before and after exercise as well as 24, 48, and 72 h post-exercise. Following adjustment for changes in plasma volume, significant changes were only found following the HV session. These included increases in HDL-C (11%) and HDL3-C (12%) 24 h post-exercise. Modifications in HDL-C were significantly different from both the LV and control sessions. In contrast, triglycerides and LCAT were significantly depressed 24 h post-exercise following the HV session when compared with immediate post-exercise values. There were no significant changes in either total cholesterol or HDL2-C at any time. The results of this study suggest that the potential of resistance exercise to affect acute modifications in the lipoprotein profile resides in the volume of exercise performed.

Influence of water run training on the maintenance of aerobic performance.

The purpose of this study was to examine the effect of a 6-wk deep water running program on the maintenance of cardiorespiratory performance (VO2max, ventilatory threshold, running economy); metabolic measurements of blood glucose, blood lactate, and plasma norepinephrine; and body composition. Sixteen trained male runners (VO2max = 58.6 +/- 3.6 ml.kg-1.min-1) were assigned to one of two groups matched by VO2max, treadmill run (R) or water run (WR). Subjects participated in their respective training programs, which consisted of workouts of a) 30 min at 90-100% VO2max and b) 60 min at 70-75% VO2max alternated daily for 5 d.wk-1. Following 6 wk of workouts, no significant intra- or intergroup differences were observed for treadmill VO2max for R (pre = 58.4 +/- 2.3, post = 60.1 +/- 3.6 ml.kg-1.min) and WR (pre = 58.7 +/- 4.7, post = 59.6 +/- 5.4 ml.kg-1.min-1). Similarly, ventilatory threshold was unaltered in R (pre = 47.5 +/- 1.8, post = 48.2 +/- 3.3 ml.kg-1.min-1) and WR (pre = 46.5 +/- 6.4, post = 47.4 +/- 6.7 ml.kg-1.min-1), nor were there any changes in running economy in R (pre = 48.4 +/- 2.3, post = 48.9 +/- 2.0 ml.kg-1.min-1 at 255 m.min-1) and WR (pre = 51.8 +/- 2.0, post = 48.9 +/- 2.2 ml.kg-1.min-1 at 255 m.min-1). No significant differences were observed within or between groups for maximal blood glucose, blood lactate, and plasma norepinephrine concentration as well as for body composition indices. It was concluded that deep water running may serve as an effective training alternative to landbased running for the maintenance of aerobic performance for up to 6 wk in trained endurance athletes.

Changes in oestrogen receptor protein, mRNA expression and localization in the endometrium of cyclic and pregnant gilts.

Conceptus secretion of oestrogen on Day 11 of gestation is involved with establishment of pregnancy in the pig. Changes in oestrogen receptor (ER) protein, mRNA and cellular localization in the endometrium were evaluated during the oestrous cycle and early pregnancy of the gilt. In nonpregnant gilts, concentration of nuclear ER in the endometrium increased from Days 0 to 12 followed by a decline on Day 15 of the oestrous cycle. In pregnant gilts, changes in endometrial nuclear ER during Days 10, 12, 15 and 18 were similar to that in cyclic pigs. Analysis of endometrial ER mRNA expression did not detect any difference between cyclic and pregnant pigs between Days 10 and 15 postoestrus. Expression of ER mRNA in endometrium of cyclic and pregnant gilts was greatest on Day 10 followed by a decline on Day 15. Endometrial ER mRNA increased on Day 18 of the oestrous cycle, but remained low during pregnancy. Immunocytochemical localization of ER in the endometria of cyclic and pregnant gilts indicated that there was intense staining for ER in stromal cells and moderate to strong staining in surface and glandular epithelial cells during oestrus (Day 0) and Day 18 of the oestrous cycle. However, stromal ER staining was absent from Days 5 to 15 of the oestrous cycle and continued to be suppressed on Day 18 of pregnancy. Immunocytochemical staining of ER in the surface and glandular epithelium was readily detectable from Days 0 to 12 of the oestrous cycle and during pregnancy. Intensity of staining for ER declined in surface epithelial cells on Day 15 in both cyclic and pregnant pigs whereas positive staining for ER in glandular epithelium was absent. Staining for ER on uterine surface epithelial cells increased during pro-estrus (Day 18) of cyclic gilts but remained similar to Day 15 in pregnant gilts. Changes in endometrial ER protein, mRNA and localization in surface epithelium are consistent with a physiological role for conceptus oestrogen secretion in uterine function and maternal recognition of pregnancy in the pig.

Endocrine and endometrial secretory protein changes associated with uterine receptivity in sheep.

Crossbred ovariectomized ewes were treated with steroid therapies determined previously to be adequate (progesterone-primed) or inadequate (unprimed) for embryonic development in order to determine actual serum concentrations of replaced steroid hormones achieved by such treatments and to identify secreted endometrial proteins that might mediate uterine receptivity. Ewes received estradiol-17 beta on day 0, and on days 1-4, either vehicle (unprimed; N = 16) or progesterone (primed; N = 16) daily. All ewes then received "estrus estradiol" (at 8 hr-intervals), followed by "maintenance progesterone" (at 12 hr-intervals), to mimic endocrine profiles of intact ewes at and following estrus. Jugular blood samples were obtained at 4-hr intervals from 6 ewes/treatment on day 0-15 to determine serum progesterone, estradiol, and PGFM concentrations. Endometrium from two ewes/treatment on days 11-15 was cultured in vitro with [3H]leucine and radiolabeled proteins in media were analyzed electrophoretically. Results demonstrated that 1) treatments generated transient serum estradiol levels slightly greater than those reported in intact animals at estrus, 2) serum progesterone concentrations due to treatments were similar to those reported in the luteal phase of intact ewes, 3) progesterone-priming was specifically associated with a small, sustained (24-36 hr) elevation in serum PGFM, and that 4) priming was not associated with the presence or absence of major, secreted endometrial proteins that might act either as factors required for development or as embryotoxins. These results suggest that positive effects of progesterone-priming on embryo survival are not due to pharmacological doses of exogenously administered hormones, nor are due to changes in secretion of hormonally-regulated, major endometrial proteins.

Lack of effects of indomethacin on estradiol feedback control of luteinizing hormone in ovariectomized ewes.

We tested the hypothesis that indomethacin, a potent inhibitor of prostaglandin synthesis, would modify estradiol's effects on tonic and surge concentrations of LH in chronically ovariectomized ewes during the anestrous season. Ewes (n = 21) were assigned randomly to one of four treatments: Vehicle+Blank (n = 5); Indomethacin+Blank (n = 6); Vehicle+Estradiol (n = 5); or Indomethacin+Estradiol (n = 5). On d=0 (hr = 0), ewes began to receive i.m. injections of either indomethacin (4 mg/kg body weight) or corn oil every 8 hr for 9 d. Blood samples were collected every 12 min for 6 hr beginning at -6 hr, +18 hr, and on day 8 (relative to initial injections of indomethacin or vehicle) to assess tonic patterns of secretion of LH. At +24 hr, ewes received blank- or estradiol-containing Silastic implants and were bled hourly for 48 hr. On day 9, ewes received 50 micrograms of GnRH i.v. and were bled hourly for 8 hr. Serum samples were assayed for LH. Indomethacin had no effect on the following parameters of LH secretion: 1) mean concentrations (ng/ml; 8.4 +/- .7 vs 8.9 +/- .8; P > .1), 2) pulse frequency/6 hr (4.5 +/- .4 vs 4.1 +/- .4; P > .1) or 3) pulse amplitude (ng/ml; 15.3 +/- 1.1 vs 14.9 +/- 1.2; P > 1). Estradiol elicited a surge of LH which began 18.9 +/- 1.7 hr after implant insertion, reached a mean peak concentration of 95.3 +/- 20.1 ng/ml, and did not differ with respect to indomethacin treatment (P > .1).(ABSTRACT TRUNCATED AT 250 WORDS)

Basis of norgestomet action as a progestogen in cattle.

Norgestomet is the progestational component present in Syncro-Mate-B, which is used to synchronize estrus in cattle. In post-partum cows, luteal phases anticipated to be short following first ovulation are of normal length when cows are pretreated with norgestomet. Because Syncro-Mate-B is used experimentally as a progestogen to affect uterine function, these studies were conducted to investigate how norgestomet acts at the level of the uterus. Receptor binding assays and a sensitive estrogen bioassay in tissue culture were used to address the possibility that some effects of norgestomet might be mediated through interaction of this compound with steroid hormone receptors other than the progesterone receptor (rP). The source of receptors was high-speed cytosol, prepared from bovine uterine endometrium, which was obtained from cyclic cows. Results of single-point and complete competition analyses comparing norgestomet and progesterone indicated that norgestomet competed even more effectively than did progesterone for specific binding of [3H]progesterone to rP. Results of similar studies, which compared the abilities of norgestomet and diethylstilbestrol to compete with [3H]estradiol for binding by uterine endometrial estrogen receptors (rE), provided no evidence for norgestomet competitive binding to rE. In MCF-7 breast cancer cell bioassays, norgestomet showed weak estrogenic activity, but only at concentrations greater than 1 micromolar. Finally, norgestomet did not compete with [3H]triamcinolone acetonide when present in an 100-fold excess, and only competed with [3H]dexamethasone for binding by endometrial glucocorticoid receptors (rG) when present in the micromolar range. We conclude that, at the concentrations used in synchronizing estrus, norgestomet interacts with bovine endometrium as a progestogen and that its biological actions occur through binding of this compound to rP present in target tissues.