Evaluation and diagnosis of acrosome function/dysfunction in the stallion.
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Acrosome↗
Biomedical subjects
D Varner
Publications and source records attributed to D Varner.
Effect of intrauterine treatment with prostaglandin E2 prior to insemination of mares in the uterine horn or body.
Two trials were conducted to investigate the effects of intrauterine infusion of PGE2 and uterine horn insemination on pregnancy rates in mares achieved by breeding with a suboptimal number of normal spermatozoa. Estrus was synchronized and mares were teased daily with a stallion to detect estrus. Mares in estrus were examined by transrectal palpation and ultrasonography to monitor follicular status. On the first day a 35-mm diameter follicle was present, hCG (1500 IU, iv) was administered and the mares were bred the next day. Mares (Trial 1, n = 34; Trial 2, n = 28) were inseminated with 25 million total spermatozoa from either a stallion with good semen quality (Trial 1) or poor semen quality (Trial 2). In each trial, mares were assigned to 1 of 4 treatment groups as follows: Group PGE-HI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; Group PGE-BI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body; Group SAL-HI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; or Group SAL-BI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body. After breeding, mares were examined daily by transrectal ultrasonography to confirm ovulation, and were re-examined 14 to 16 d after ovulation for pregnancy status. Data were analyzed by Chi-square. Overall pregnancy rates were 59% for stallion 1 and 29% for stallion 2. Group pregnancy rates did not differ for mares bred by either stallion (P > 0.10). Pregnancy rates were not altered by horn insemination for either stallion (P > 0.10). Intrauterine infusion of PGE2 improved pregnancy rate in mares bred by the stallion with good quality semen (P < 0.05), but did not alter pregnancy rate in mares bred by the stallion with poor quality semen (P > 0.10). Further research is warranted to determine if intrauterine infusion of PGE2 will enhance spermatozoal colonization of the oviduct and pregnancy rates in mares, and if PGE-treatment will improve pregnancy rates achieved by subfertile stallions.
Animals↗
Administration of oxytocin immediately after insemination does not improve pregnancy rates in mares bred by fertile or subfertile stallions.
It is probable that reduced pregnancy rates in mares bred to subfertile stallions is attributable, in part, to the reduced number of normal spermatozoa that colonize the oviduct. Administration of oxytocin stimulates both uterine and oviductal contractility. The hypothesis that oxytocin may enhance sperm transport to/into the oviducts, and thereby increase pregnancy rates, was tested in 2 trials. For both trials, fertile estrous mares with follicles > or = 35 mm in diameter were inseminated once at 24 h after administration of 1500 to 2000 U hCG. The inseminate dose was limited to 100 million spermatozoa in order to lower pregnancy rates and thus increase the chance of detecting a treatment effect. Pregnancy status was determined by transrectal ultrasound examination 14 to 16 d after insemination. In Trial 1, 49 mares were inseminated with 4 mL extended semen from 1 of 3 stallions (1 fertile and 2 subfertile males). Immediately after insemination, the mares were administered either 20 U oxytocin or 1 mL saline intravenously. In Trial 2, 51 mares were inseminated with 4 mL extended semen from 1 of 4 stallions (1 fertile and 1 subfertile male used in Trial 1, and 2 additional fertile males). Immediately after insemination, and again 30 min later, mares were administered either 5 U oxytocin or 0.25 mL saline intramuscularly. To test for effects of treatment with oxytocin and for the interaction between semen quality and treatment, a generalized linear mixed regression model was used that accounted for the split-plot design (treatment within stallions), the random effect of stallion, the fixed effect of semen quality, the binary outcome of a single breeding trial, and the varying number of trials per stallion/treatment groups. Three treatment protocols or regimens were used: placebo, 5 U oxytocin injected twice intramuscularly, and 20 units oxytocin injected twice intravenously. Semen was classified as high (fertile stallions) or low (subfertile stallions) quality. No interaction between semen quality and treatment was detected (P > 0.10). The pregnancy rate of mares treated with oxytocin immediately after insemination was 30% (15/50) compared with 50% (25/50) for mares treated with saline immediately after breeding. Administration of oxytocin did not affect pregnancy rates (P > 0.10).
Animals↗
Use of prostaglandin E2 to ripen the cervix of the mare prior to induction of parturition.
Eleven light-breed pregnant mares (335 to 347 d gestaton) were used to evaluate the use of prostaglandin E2 as a cervical ripening agent prior to induction of parturition during the months of April and May. Six hours prior to induction, each mare's cervix was examined per vagina for softness and dilation. Each mare was then assigned to 1 of 2 treatment groups: Group PGE mares (n = 7) received 2.0 to 2.5 mg prostaglandin E2 deposited intracervically; Group SAL mares (n = 4) received 0.5 mL of sterile NaCl deposited intracervically. Six hours later, the mares were readied for parturition by wrapping the tail, scrubbing and rinsing the perineum and udder, and examining the cervix as previously described. Each mare was then administered 15 U, i.v. oxytocin at 15-min intervals until the chorioallantois ruptured. Intervals from initial oxytocin injection until rupture of the chorioallantois, from initial oxytocin injection until delivery of the foal, from delivery of the foal until the foal stood unassisted, and from delivery of the foal until the foal suckled were recorded. Mean cervical dilation immediately prior to induction of parturition tended to be greater in Group PGE mares (3.9 +/- 1.7 cm) than in Group SAL mares (1.9 +/- 1.9 cm; P = 0.10). Mean change in cervical dilation over the 6-h period prior to induction (3.4 +/- 1.9 cm vs 1.5 +/- 2.1 cm), mean number of injections of oxytocin required until the chorioallantois ruptured (1.9 +/- 0.7 vs 2.5 +/- 1.0), and mean intervals from initial injection of oxytocin to rupture of the chorioallantois (20 +/- 10 min vs 28 +/- 19 min) and delivery of the foal (28 +/- 7 min vs 34 +/- 22 min) were not different between Group PGE and SAL mares, respectively (P > 0.10). The proportion of foals that stood within 1 h of birth also did not differ between Group PGE foals (6/7; 86%) and Group SAL foals (3/4; 75%; Chi-square = 0.17; P > 0.10). The proportion of foals that nursed within 2 h of birth was higher in Group PGE foals (6/7; 86%) than in Group SAL foals (1/4; 25%; Chi-square = 4.02; P < 0.05). Premature separation requiring manual rupture of the chorioallantois at the vulvar labia occurred in 1 Group PGE mare (cervical dilation of 1.5 cm at time of induction) and 1 Group SAL mare (cervix closed and firm at time of induction). Foals born from the 2 mares with premature placental separation had the longest intervals from initial oxytocin injection to delivery, delivery to ability to stand unassisted, and delivery to suckling within their respective treatment groups. In summary, it appears that cervical ripening prior to induction of parturition favors shorter deliveries and foal vigor. Intracervical administration of prostaglandin E2 may prove useful for ripening the cervix of the mare prior to induction of parturition. Further studies are indicated to determine optimal dosage and method of administration of prostaglandin E2.
Allantois↗
Laparoscopic vs open appendectomy. Prospective randomized study of outcomes.
OBJECTIVE: To compare open appendectomy (OA) with laparoscopic appendectomy (LA) for length of the operation, complications, postoperative pain control, length of hospitalization, postdischarge recovery time, and hospital charges. DESIGN: Prospective randomized clinical trial of patients with acute appendicitis. SETTING: Tertiary care, urban teaching hospital. PATIENTS: A population-based sample of patients (aged > or = 12 years; weight, > 49.7 kg) admitted to a surgical teaching service with a clinical diagnosis of acute appendicitis. Patients were prospectively randomized to either OA or LA during a 20-month period (from April 1, 1994, to December 31, 1995). Fifty-seven patients were initially enrolled in the study; 7 did not complete the study because of a protocol violation. All remaining patients completed the study, including postdischarge follow-up. INTERVENTIONS: Two (7.4%) of the 27 patients in the LA group required conversion to OA because of technical difficulties. One patient (in the OA group) underwent a second surgical procedure for drainage of a pelvic abscess. Three patients (in the LA group) required second surgical procedures. For analysis, no crossovers were allowed and all patients remained in their originally randomized group. MAIN OUTCOME MEASURES: Length of the operation, intraoperative and postoperative complications, postoperative pain control, length of hospitalization, postdischarge recovery time, and hospital charges. RESULTS: Fifty patients (19 women and 31 men) were examined. Twenty-seven patients underwent LA, 2 requiring conversion to an OA. Twenty-three patients underwent an OA. Patient demographics were similar between groups. Statistical differences between the 2 groups were found for (1) length of the operation (median, 81.7 vs 66.8 minutes, LA vs OA groups: P < .002), (2) operating room charges (median, $3191 vs $1514, LA vs OA group; P < .001), and (3) total hospital charges (median, $5430 vs $3673, LA vs OA group; P < .001). No statistical differences between the 2 groups were found for (1) length of hospitalization (median, 1.1 vs 1.2 days, LA vs OA group), (2) pain control (mean, 4 vs 3.7 of 10 [0 indicates least pain; 10, most pain], LA vs OA group), (3) recovery time (time necessary before returning to work or school) (median, 14.0 days for both groups), and (4) complications (5 vs 1, LA vs OA group). CONCLUSIONS: Laparoscopic appendectomies and OAs are comparable for complications, postoperative pain control, length of hospitalization, and recovery time. Patients who underwent an OA had a shorter operative time and lower operating room and hospital charges. Laparoscopic appendectomy does not offer any proved benefits compared with the open approach for the routine patient with acute appendicitis.
Adolescent↗
Biodegradable estradiol microspheres do not affect uterine involution or characteristics of postpartum estrus in mares.
Quarterhorse mares were used to investigate effects of estradiol-17beta on uterine involution, duration of estrus, interval to ovulation, and fertility achieved by breeding on the first postpartum estrus. On the day of foaling, mares were injected with biodegradable poly (DL-lactide) microspheres containing either 100 mg estradiol-17beta (25 mares) or no drug (27 mares). The treatment period was considered to last for 12 to 15 d. Estrus was determined by teasing mares (n=16) with a stallion. Ovulation was detected by transrectal ultrasonographic examination of ovaries (n=48). On Days 6, 11 and 16 post partum, transrectal ultrasonography was used to measure cross-sectional diameters of the uterine body, uterine horns, and fluid within the uterine lumen (n=28). Uteri were swabbed for bacteriologic culture, and uterine biopsies were obtained from the previously gravid uterine horn on Days 11 and 16 post partum, for assessment of endometritis and morphometric analysis of endometrial histioarchitecture (n=19). Twenty-two mares were bred on foal-heat, and pregnancy was determined by transrectal ultrasonography on 14 to 16 and 30 to 35 d after breeding. With only one exception (diameter of previously gravid uterine horn on Day 11), mean values for all measures of uterine involution did not differ between treatment groups (P > 0.05). No differences were detected between treatment group means for length of estrus or interval to ovulation (P > 0.05). No differences were detected between treatment group liklihoods for recovery of potential bacterial pathogens, presence of endometritis, or presence of intrauterine fluid at 11 or 16 d post partum (P > 0.05). Pregnancy rate of mares treated with estradiol (5 11 ; 45%) was not different from that of control mares (9 11 ; 82%; P > 0.05). Estradiol treatment did not hasten uterine involution, increase duration of estrus, delay ovulation, or increase fertility in these postpartum mares.
Journal Article↗
Tritan discriminations by 1- and 2-month-old human infants.
The capacity of 1- and 2-month-old infants to make a tritan discrimination between a 4 degree, 416 nm test field and a 547 nm surround was tested by means of the forced-choice preferential looking technique. Most of the 2-month-olds and the other 1-month-olds made the tritan discrimination and must therefore have functional SWS cones. Most of the youngest 1-month-olds failed to make the tritan discrimination and therefore either do not encode or do not preserve the information ordinarily encoded by SWS cones. The implications of these data and the prior data of Hamer et al. [Vision Res. 22, 575-587 (1982)] are discussed in relation to color theory.
Adult↗
The acuity card procedure: a rapid test of infant acuity.
Forced-choice preferential looking (FPL) and operant preferential looking (OPL) procedures for testing infant acuity typically require 15-45 min to derive an acuity estimate. This article presents a new acuity assessment technique ("acuity cards") that combines FPL/OPL stimuli with an observer's subjective assessment of an infant's looking behavior. The infant is shown a series of gray cards that contain grating targets of various spatial frequencies. An observer watches the eye movement patterns and behavior of the infant and judges whether the infant can or cannot see the grating on each card in the series. Acuity is estimated as the highest spatial frequency that the observer judges the infant to be able to see. With this technique, the binocular acuity of normal infants can be estimated with reasonable accuracy in the laboratory setting in 3-5 min.
Conditioning, Operant↗
Interactions between tricarboxylic acid cycle intermediates and phosphate uptake by proximal renal cells and renal brush border membranes.
Glucose and other hexoses as well as amino acids have been shown to inhibit the renal transport of phosphate (Pi). Although studies with renal brush border membrane vesicles showed that such an inhibitory effect on Pi transport is due to the dissipation of the Na electrochemical gradient, the mechanism(s) responsible for such an action in the intact cell is not clear. The present study examined the effects of tricarboxylic acid (TCA) cycle intermediates (succinate and fumarate) and acetate on the uptake of Pi and alpha-methylglucoside (AMG) at 37 degrees C by intact rabbit renal cells. These TCA cycle compounds significantly (p less than 0.05) inhibited the uptake of both Pi and AMG. In the presence of 5-10 mM succinate the ATP content of the renal cells increased by 40% (p less than 0.02). Inhibition of succinate-induced gluconeogenesis by 3-mercaptopicolinic acid did not modify the inhibition of Pi uptake. Studies with renal brush border membrane vesicles showed that succinate inhibited Pi uptake at 15 and 60 s but not at 1 s and only under conditions of Na gradient (outside greater than inside). Succinate did not inhibit Pi uptake during Na equilibrium conditions. The data demonstrate that the succinate-induced inhibition of the Pi uptake by intact proximal renal cells is not due to competition for metabolic energy, is not related to stimulation of gluconeogenesis nor due to allosteric interaction between Pi carrier and succinate transporter. The results support the notion that the inhibition of Pi uptake by succinate in the intact renal cell is due to dissipation of the Na chemical gradient.
Animals↗
Temporal sensitivities related to color theory.
Sensitivities of color-normal observers to temporal variations in stimulus luminance and chromaticity were measured for sine-wave stimuli between 1.5 and 20 Hz. Clear differences were found in observers' sensitivities to isochromatic luminance variations and to isoluminous chromaticity variations for wavelength pairs selected to test temporal discriminability along the red-green and yellow-blue dimensions, respectively. Despite interobserver differences in individual red-green functions, a given observer's sensitivity could be described by a single curve shape specific to that observer. Overall sensitivity for yellow-blue was less than that for red-green for all observers. Differences in curve shape between red-green and yellow-blue functions are found for individual observers, but group averages reveal that the differences are not systematic. Red-green temporal sensitivity is largely unaffected by adapting backgrounds in red-green equilibrium but is attenuated at low frequencies by nonequilibrium backgrounds of the same luminance. Isochromatic luminance sensitivity is largely independent of our adapting backgrounds, but heterochromatic luminance modulation functions undergo expected changes in form.
Color↗