bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for MHC class‐l restricted cytotoxicity in the one‐way, primary mixed lymphocyte reaction
Authors: O'Brien M. A. , Holmes M. A. , Lunn D. P. , Duffus W. P. H. 
Published: June 2010

SummaryThe one‐way primary equine mixed lymphocyte reaction (MLR) was used to generate allospecific major histocompatibilty complex (MHC) class‐I‐restricted cytotoxicity in vitro. Allospecific cytotoxicity, demonstrated against Con A stimulated peripheral blood mononuclear cells (PBMC) in a 6 h chromium‐release assay, was present from approximately 72 to 168 h of primary culture and peaked between 120 and 168 h. Optimal cytotoxicity was generated at a responder to stimulator ratio of 4:1 and at an effector to target ratio of 50:1. The cytotoxicity was blocked by an anti‐equine leucocyte antigen (ELA) class‐I and an anti‐equine CD8‐homologue monoclonal antibody. An anti‐ELA class‐11 and an anti‐equine CD4‐homologue monoclonal antibody had no significant effect.
Evaluation of some prophylactic therapies for the idiopathic headshaker syndrome
Authors: MAIR T. S. , HOWARTH S. , LANE J.G. 
Published: June 2010

SummaryEighteen horses affected by the idiopathic headshaker syndrome were studied in an owner assessed trial to test the efficacy of some prophylactic therapies. Riding the affected animal with a veil over the nostrils gave varying degrees of temporary relief in three of 10 horses. Local (intra‐nasal) corticosteroid therapy was reported to be slightly effective in three of nine horses, but treatment with sodium cromoglycate, systemic corticosteroid, flunixin meglumine and an antihistamine were generally ineffective. Bilateral infraorbital neurectomy provided sustained relief in three of seven horses, but in one of these cases, a reaction at the neurectomy site necessitated another surgical procedure after six months. A fourth horse was reported to be slightly improved after neurectomy. A period of nasal irritation resulting in selfinflicted trauma was a common complication of this surgery.
A comparison of injectable anaesthetic regimens in Mammoth asses
Authors: MATTHEWS NORA S. , TAYLOR T. S. , HARTSFIELD S. M. , WILLIAMS J. D. 
Published: June 2010

SummaryXylazine (1.1 mg/kg body weight [bwt])‐ketamine (2.2 mg/kg bwt) (X/K) anaesthesia was evaluated, in nine Mammoth asses, for effectiveness and compared with two other injectable anaesthetic combinations: xylazine (1.1 mg/kg bwt) ‐ butorphanol (0.044 mg/kg bwt)‐ketamine (2.2 mg/kg bwt) (X/B/K); and xylazine (1.1 mg/kg bwt)‐tiletamine‐zolazepam (1.1 mg/kg bwt) (X/T). All drugs were given intravenously (iv). Heart rate, respiratory rate, systolic blood pressure, arterial blood pH, PCO2, PO2, recumbency time and number of attempts to stand were measured. Quality of induction and recovery, muscle relaxation and response to stimulus were evaluated subjectively. One animal did not become recumbent with X/K. Recumbency times were significantly (P < 0.05) different: the shortest time was with X/K (24 mins) and the longest time with X/T (46 mins), with X/B/K, it was 37 mins. Asses required significantly more attempts to stand with X/T (n=3) than with X/K (n/1) or X/B/K (n=2). No significant differences in heart rate, respiratory rate, blood pressure, arterial PO2or PCO2were detected between groups. Arterial pH was significantly lower at 15 mins in the X/B/K and X/T groups than in the X/K group. Although X/K generally produced effective immobilisation, the combinations of X/B/K and X/T appeared to be more satisfactory and relatively safe, and provided longer recumbency times and increased muscle relaxation compared with X/K.
Review Article: Blood platelets and their role in the genesis and sequelae of intestinal ischaemia
Authors: Evans R. J. 
Published: June 2010

SummaryActivation of platelets is the key step in the formation of macroscopic thrombi and emboli and in micro‐thromboembolism associated with disseminated intravascular coagulation (DIC). Macroscopic thrombosis may compromise the blood supply of the gut. Strangulation or infarction of the gut, from whatever cause, commonly result in endotoxaemia, DIC and multiple organ failure. Equine platelets may be activated physiologically by a wide range of agonists. Information is now emerging about the receptor populations and intracellular signalling pathways of equine platelets. Less is known about platelet‐vessel wall interactions in the horse or the mechanisms of platelet activation in endotoxaemia. Antiplatelet drugs have been disappointing in endotoxaemia, possibly because of the relative unimportance of thromboxane production in the activation of equine platelets. Dextran 70, however, is a useful treatment of thromboembolic colic and the mechanism of action is now beginning to be understood.
Gastric secretion in foals: measurement by nasogastric intubation with constant infusion and aspiration
Authors: Andrews F. M. , Jenkins Christine C. , Frazier Donita , Blackford J. T. 
Published: June 2010

SummaryA technique comprising constant infusion and aspiration via nasogastric tube was used to quantify basal gastric secretion in 9 healthy foals aged 4–7 months and weighing 156 to 215 kg. Gastric fluid was collected continuously for 3 h from anin situdouble lumen nasogastric tube attached to a constant suction device (5–10 mmHg). Phenol red (50 mg/litre), an inert marker, was infused continuously (250 ml/h) during the same period to determine loss of gastric fluid through the pylorus. Samples were collected every 15 mins and aspirated volume (VASP), pH, phenol red recovery (PRR) and hydrogen ion concentration (AO) were measured. Gastric secretory volume (VS) and acid concentration (ACD) were calculated. The mean (sd) VASPwas 6.54 (1.31) ml/kg bodyweight (bwt)/h; pH was 1.76 (0.25), PRR was 77.7% (11.7), and AO was 0.43 (0.18) mmol/kg bwt/h. Mean (sd) ACD and VSwere 59.17 (18.88) mmol/litre and 7.07 (1.73) ml/kg bwt/h, respectively. The AO, ACD, and VSwere corrected for PRR. This technique is an alternative to invasive procedures and may be useful for evaluating basal and stimulated gastric secretion in foals and horses.
Pharmacokinetics and antisecretory effects of intravenous omeprazole in horses
Authors: Jenkins Christine C. , Frazier Donita L. , Blackford J. T. , Andrews F. M. , Mattsson H. , Olovsson S‐G. , McCleod Margaret 
Published: June 2010

SummaryEight young female horses with chronic gastric cannulae received 0.5 mg omeprazole/kg bwt iv once daily for 5 consecutive days. Gastric secretion was measured on the 1st and 5th day. Basal secretion was determined 1 h before and 1 h after the omeprazole dose, followed by pentagastrin stimulation for 2 h. Gastric juice samples were collected from the cannula every 15 mins for the determination of volume, pH, acidity, and acid outputs. As control, sterile water was similarly administered to all 8 horses. Pharmacokinetic evaluation of intravenous omeprazole was determined concurrently on the 1st and 5th day of administration.Omeprazole reduced both basal and stimulated acid output (mmol H+/h) by more than 90%, with a significant increase in gastric juice pH both on the 1st and 5th day of administration. A trend suggesting a long duration of inhibitory action was observed 23 h after the 4th dose of omeprazole since 58% of gastric acid output was inhibited. Thus omeprazole shows potential as a once a day antisecretory drug in horses.Plasma omeprazole concentration versus time profiles were best described using a two‐compartment model. There was no statistical difference between the pharmacokinetic disposition of omeprazole on Days 1 and 5. The elimination half‐life of intravenous omeprazole was about 30 mins.
Pathophysiology, cellular and molecular mechanisms of foetal growth retardation
Authors: HAN V. K. M. 
Published: June 2010

SummaryIn mammals, size at birth is the outcome of length of gestation and rate of foetal growth. In the absence of premature delivery, foetal size within species is determined principally by foetal growth rate which is dependent on both genetic and epigenetic factors. Failure of either of these mechanisms leads to foetal growth retardation. In mammals, including human infants, foetal growth retardation can occur naturally or pathologically. One major cause for natural foetal growth retardation or runting is the increase in litter size. In many cases, however, the cause of runting is unknown. Parental genotype or antigenic differences between the mother and the developing conceptus may be potential causes. Pathological foetal growth retardation or intrauterine growth retardation (IUGR) is due to genetic causes (chromosomal abnormalities or inherited syndromes) or epigenetic causes (intrauterine infections, toxins and chemicals, maternal diseases of pregnancy affecting the placenta). The underlying pathophysiological processes that occur at the cellular and molecular level in IUGR are still unknown. Reduction in the supply of substrates that are necessary for normal cellular function, and alteration in mediator molecules that regulate cellular growth and differentiation, are important mechanisms. A decrease in growth promoting factors or an increase in growth inhibitory factors may lead to growth failure. Growth factors and their receptors are expressed in the developing embryo (as early as the 1–2‐cell stage), placenta and maternal uterine tissues, suggesting that these molecules may play a role in regulating normal growth and differentiation of the conceptus as well as maternal reproductive tissues. The local expression within developing tissues indicates that these factors act in either autocrine or paracrine mechanism. Recent studies using gene targeting to knock out one allele of insulin‐like growth factor II (IGF II) gene in mice which resulted in growth retarded pups at birth, strongly support the importance of local IGF II in regulating tissue growth. Foetal growth retardation has also been induced experimentally in several species using one of the following methods: (i) maternal undernutrition, (ii) chronic hypoxia, (iii) prolonged reduction in uterine blood flow, (iv) reduction in placental size, and (v) endocrine alterations. These models provide useful information on the physiological mechanisms underlying a specific type of growth retardation. These in‐vivo models and in‐vivo tissue culture models can now be analysed by biochemical and molecular biological techniques to unravel the basic mechanisms that underlie foetal growth retardation.
Some aspects of perinatal maturation and adaptation
Authors: MELLOR D. J. 
Published: June 2010

SummaryPhysiological challenges facing the perinatal individual are huge. This is partly because of the marked and abrupt change from the intrauterine to the extrauterine environment, but also because the physiological responses to that change depend upon systems whose maturation is affected markedly by birth. Perinatal maturation appears, therefore, both to precede and accompany the physiological adaptations required for neonatal survival. This review does not provide a comprehensive coverage of perinatal physiology but directs attention towards evaluating constraints on foetal and neonatal thermogenesis, especially those imposed by postnatal availability of metabolic fuels in body reserves deposited before birth and acquired in colostrum and milk after birth. The relative importance of the supply of carbohydrate from body reserves and colostrum is examined. Carbohydrate is the major rate‐limiting substrate with respect to heat production. It is shown that in the normal birth environments of several species, including the horse, colostral supply of lactose is not adequate to meet the entire carbohydrate needs of the neonate. It must, therefore, draw on its body glycogen reserves to sustain the required rates of heat production during the first day after birth. Gastrointestinal maturation and growth play a major part in the initial and continued provision of substrates for general metabolism and growth. Pre‐natal and post‐natal development of the stomach and intestines in a number of species are considered, including their disproportionately large growth compared with the body as a whole during the first 1–3 days after birth. Possible contributions to gastro intestinal growth and body growth of milk‐borne growth factors such as epidermal growth factors and the insulin‐like growth factors are considered. The role, as a possible significant stimulus to gastrointestinal growth and maturation immediately after birth, of the high levels of these growth factors in colostrum is evaluated.
Use of sperm binding to homologous hemizona pellucida to predict stallion fertility
Authors: FAZELI A. R. , STEENWEG W. , BEVERS M. M. , BRACHER V. , PARLEVLIET J. , COLENBRANDER B. 
Published: June 2010

SummaryEquine oocytes were obtainedpost mortemfrom slaughterhouse ovaries and by transvaginal ultrasound‐guided follicle aspiration. The oocytes were denuded and stored in salt solution at 4°C. On the day of the experiment the oocytes were bisected by micromanipulation surgery, thus providing two equal matching hemizonae from each oocyte. Three pairs of stallions were formed, each consisting of a fertile and subfertile Dutch Warmblood stallion. Matching hemizonae from 5 oocytes were used for each pair of fertile and subfertile stallions and the number of spermatozoa bound to the outer‐side of each hemizona during incubationin vitrowas assessed. The numbers of bound spermatozoa from fertile stallions were significantly higher than those from subfertile stallions (P<0.05). The results of this investigation encourage further use of the hemizona assay for evaluation of stallion fertility.
Atlas of chromatin configurations of germinal vesicle‐stage and maturing horse oocytes
Authors: HINRICHS K. , SCHMIDT A. L. , SELGRATH J. P. 
Published: June 2010

SummaryThe fluorescent, DNA‐specific label, Hoechst 33258, was used to determine the chromatin configuration of immature and maturing horse oocytes. The stain was simple to use and effective in revealing the chromatin of horse oocytes without need for clearing of lipid. The chromatin configuration of oocytes known to have a germinal vesicle fell into two major categories: fluorescent nucleus, in which the entire nucleus fluoresced with or without clumps of chromatin within; and compact chromatin, in which only one compact mass of chromatin was visible. These classifications were further broken up into diffuse, spotty or crinkled fluorescing nucleus, and compact, faded or loosely compact condensed chromatin. The physiological relevance of the different chromatin configurations of germinal vesicle stage oocytes is presently unknown. The chromatin configurations of maturing oocytes were similar to those seen in other species.
Repeated transvaginal ultrasound‐guided follicle aspiration in the mare
Authors: BRACHER VERENA , PARLEVLIET JOYCE , FAZELI A. R. , PIETERSE M. C. , VOS P. L. A. M. , DIELEMAN S. J. , TAVERNE M. A. M. , COLENBRANDER B. 
Published: June 2010

SummaryTransvaginal ultrasound‐guided follicle aspiration was performed repeatedly in 5 Dutch Warmblood mares during a time span of 3 months (mid‐June‐mid‐September 1992). During 24 aspiration sessions (4–7/mare), 200 follicles were aspirated and 34 oocytes retrieved, giving oocyte recovery rates of 12.3% and 24.4% when using single channel needles or double barrel needles respectively. There was no significant effect of cycle stage on oocyte recovery rates. Follicle aspiration performed without any hormonal pretreatment gave significantly higher oocyte recovery rates of 26.9%, compared with 8.2 and 15.3% for pretreatments with prostaglandin F2α and human chorionic gonadotrophin respectively. Measurements of daily plasma progesterone concentrations in the mares revealed that follicle aspiration induced luteinisation of the follicles within 1–6 days after aspiration, resulting in a progesterone pattern similar to that of a normal oestrous cycle with ovulation when follicles were aspirated during oestrus, or in prolonged dioestrus in the mares in which follicle aspiration was performed during the luteal phase. The procedure was well tolerated by the animals and no clinical side effects were noted. This technique provides a non‐invasive, relatively simple method for the repeated puncture of multiple immature and preovulatory follicles in the mare and the possibility of obtaining up to 6 oocytes per mare in a single follicle aspiration session.
The hatching process of equine embryos in vitro
Authors: HOCHI S. , BRAUN J. , OGURI N. 
Published: June 2010

SummaryBlastocysts (5 unexpanded, 5 expanding, 2 hatched) were recovered non‐surgically between 144 and 192 h after detection of ovulation. Unexpanded and expanding embryos were cultured (TCM199 + 10% foetal bovine serum) for 10 days. Mean diameter was 168.0 μm for unexpanded and 251.0 μm for expanding blastocysts, respectively. Unexpanded embryos started to hatch from the zona pellucida (ZP) when their diameter reached 405.4 μm (embryonic age 240.0 h). Four embryos squeezed through a small opening in the ZP whereas 1 embryo gradually tore open the ZP. Three embryos completed the hatching process within 96–120 h. In contrast, expanding embryos started to hatch at a mean diameter of 499.8 μm (embryonic age 192.0 h). Four embryos escaped from the ZP within 12 h. One embryo squeezed through the ZP but did not shed the ZP entirely during culture. In‐vitro hatched embryos continued to expand spherically until reaching a maximum mean diameter of 1141.7 μm (unexpanded embryos) and 2765.0 μm (expanding embryos), except for 1 embryo which attached to the bottom of the culture dish. In completely hatched embryos, no capsule could be detected at x200 magnification after staining. Three embryos which did not entirely hatch from the ZP until the end of culture had a capsule remaining inside the ZP. In 1 case, a thin acellular layer was detected in the shed ZP after 0.3% trypsin treatment. Both freshly recovered hatched blastocysts (diameter 640 μm, 697 μm) had a clearly visible capsule around the trophectoderm cells. Equine blastocysts not only lost their zona pellucida but also their capsule during the hatching process in vitro.
Purified pig FSH increases the rate of double ovulation in mares
Authors: FORTUNE JOANNE E. , KIMMICH T. L. 
Published: June 2010

SummaryA commercial preparation of porcine FSH (Folltropin) was used to determine whether injections of FSH early in the oestrous cycle, before a large dominant follicle is present, can stimulate multiple ovulations in cycling mares. In the 1990 and 1991 breeding seasons, after injection of 8, 16 or 32 mg FSH twice daily beginning on Day 6 and PGF2α on Days 5 and 6, the rate of multiple ovulation was increased significantly to 1.83, 1.54, and 1.50, respectively, compared with 1.19 for saline‐injected controls. All multiple ovulations were double ovulations. In 1992, mares were injected with 8 mg FSH twice daily beginning on Day 3, with injection of PGF2α once daily on Days 3–6 (‘early’ group) and the response compared with that of the same mares to the protocol used in 1990‐91 (‘late’ group). PGF2α injection caused a rapid decline in plasma progesterone in both groups. FSH did not increase ovulation rate in either group but the rate of double ovulations was increased in the ‘early’ group, for saline‐ and FSH‐treated mares, in comparison with untreated control cycles for the same mares.Ultrasonographic analysis of growth and regression of individual follicles ≥15 mm and ≥25 mm in mares treated during the 1990‐92 breeding seasons revealed no consistent effect of FSH treatment on those follicular populations. These results suggest that treatment with high doses of a commercial preparation of porcine FSH can produce a modest increase in ovulation rate. Although the increase in ovulation rate was small, the response was consistent; no mare ovulated more than 2 follicles and double ovulations were synchronous, occurring on the same or succeeding days in almost all mares.
Effect on ovulation rate of passive immunisation of mares against inhibin
Authors: McCUE P. M. , HUGHES J. P. , LASLEY B. L. 
Published: June 2010

SummaryFifteen light‐horse mares were monitored daily by palpation and ultrasonography for one oestrous cycle and then randomly divided into two treatment groups. Five mares were treated with 2 litres of normal ovariectomised mare plasma (OVX) on Day 10 after ovulation and 10 mares received 2 litres anti‐inhibin plasma (a‐INH) beginning on Day 10 after ovulation. Mares receiving OVX plasma all had single ovulations after treatment, while 5 of the 10 mares receiving a‐INH plasma had multiple ovulations (mean 1.6 ± 0.2, range 1–3). No significant effect of a‐INH plasma treatment was detected in plasma concentrations of FSH, oestradiol or progesterone. These results demonstrate that passive immunisation of mares with a‐INH plasma can induce multiple ovulations, and thus eliminate the need for daily gonadotrophin treatment or a prolonged series of active inoculations against inhibin.
Habituation of horses to treadmill locomotion
Authors: BUCHNER H. H. F. , SAVELBERG H. H. C. M. , SCHAMHARDT H. C. , MERKENS H. W. , BARNEVELD A. 
Published: June 2010

SummaryHabituation to treadmill locomotion was investigated in ten Dutch Warmblood horses during a one‐week training programme. Kinematics of the horses were recorded using a CODA‐3 system and unidirectional accelerometers attached to all hooves. Horses were exercised for five days, twice a day at the walk and trot for five minutes at both gaits. Temporal and spatial stride variables and vertical trunk movement were analysed.The results indicate differences in habituation between different variables and gaits. At the walk, changes in stride duration and limb movement angle were found up to the last measurement. At the trot, all variables including constancy of stride approached constant values by the third session. At the beginning of each training session rapid adaptation occurred, disregarding the first minute of a session for locomotion studies. In conclusion, locomotion analysis at the trot requires training for a minimum of two sessions. For measurements at the walk, longer periods are recommended.
Treadmill training induced changes to some kinematic variables measured at the canter in Thoroughbred fillies
Authors: CORLEY J. M. , GOODSHIP A. E. 
Published: June 2010

SummarySix Thoroughbred fillies undertook a high intensity treadmill exercise programme over an 8 week period. Kinematic parameters of the left front limb were measured using the MacReflex system as the horses were cantered on a left lead. Measurements were made as the horses performed a standardised stepwise exercise test on the treadmill (speeds 7‐11m/s, 0% slope.) The aim was to study objectively the effects of training on the equine locomotor apparatus and to test the hypothesis that horses would display mechanical adaptation to aspects of their gait, as a result of treadmill training. The variables measured were stride length; stride frequency; stance time, as a percentage of stride time; relative movements of limb joints in the X (horizontal) and Y (vertical) directions; angles about the carpus and fetlock joints; and total ranges of motion of the carpus and fetlock joint. Statistical significance was chosen at the level p<0.05. Training induced significant changes to several aspects of the stride cycle. Percentage stance times were reduced across all speeds and significant changes were observed in the movements of the limb joints resulting in increased vertical hoof lift. Significant increases were also seen in the carpal and fetlock joint ranges of motion and also in carpal joint angles. The results suggest that the training regime employed produced significant alteration in stride kinematics at the canter.