bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on equine prematurity 3: Insulin secretion in the foal during the perinatal period
Authors: FOWDEN ABIGAIL L. , SILVER MARIAN , ELLIS LYNN , OUSEY JENNIFER , ROSSDALE P. D.
Published: April 2010

The factors influencing β cell function in the foetal and neonatal foal have been investigated in chronically catheterised foetal foals and in newborn foals delivered either spontaneously at term or by induction at different gestational ages. Insulin was detected in the foetal plasma from as early as 150 days of gestation (term = 340 days) and during the last third of gestation the foetal /3 cells responded to exogenous administration of glucose and arginine and to endogenous variations in the glucose level. Insulin secretion by the foetal ft cells was depressed by anaesthesia and surgery. At birth, there was a significant positive correlation between the plasma concentrations of insulin and glucose irrespective of the maturity at birth or type of delivery (r = 0.86, n = 39, P < 0.01). The slope of this relationship was significantly less than that relating the postoperative foetal concentration but only when delivery was difficult or prolonged was the ft cell sensitivity to glucose completely abolished. At birth, there were no significant differences in the plasma concentrations of insulin or glucose between full term foals delivered spontaneously or by induction. However, the spontaneously delivered foals showed a transient increase in the insulin concentration 15 mins after birth which was not observed in the full term foals delivered by induction. Plasma glucose concentrations were maintained during the 2 h after birth in the absence of sucking in both the induced and the spontaneously delivered full term foals. Premature foals had significantly lower plasma glucose concentrations at birth than full term foals. Their plasma glucose levels also fell during the 2 h after birth. Exogenous infusion of glucose 2 h after birth elicited a rapid release of insulin in the full term foals but caused only a small and delayed ft cell response in the premature animals. These observations demonstrate that the pancreatic β cells of the foal are functional and responsive to a variety of stimuli during the perinatal period and that insulin secretion in the immediate post natal period is influenced by the maturity of the foal at birth.
Standardised terminology for the description and analysis of equine locomotion
Authors: LEACH D. H. , ORMROD K. , CLAYTON H. M.
Published: April 2010

Terminology for the analysis of equine locomotion is reviewed and the most appropriate terms selected for use by research workers in this field. Each cycle of limb movement comprises a stance phase, when the hoof is in contact with the ground, alternating with a swing phase. The stance phase is subdivided at the mid‐stance position into an initial decelerative phase followed by a propulsive phase. When the stance phases of different limbs occur concurrently, the term overlap refers to the duration of simultaneous ground contact. Single support is the term used to describe the phase when the limb is in its stance phase unaided by any other limb. A gait consists of a limb coordination pattern repeated at each stride. The start and finish of the stride must be designated as a prerequisite to the determination of stride length, stride duration and stride frequency. In asymmetrical gaits, such as the gallop, the stride as a whole will have a stride stance phase, when one or more limbs are in contact with the ground, and a suspension phase. In symmetrical gaits, such as the trot and pace, the stride consists of left and right stance phases and suspension phases. Advanced placement and advanced lift off measure the time between ground placement and lift off respectively of consecutive limbs. The line of motion indicates the progressive movement of the centre of gravity in the X‐Y plane. Measurements in the Y‐Z plane, such as line gait and overcrossing, describe the ground placement of the hooves relative to the line of motion. Diagonal width is the distance between diagonal limb pairs in this plane.
Equine cytogenetics: Role in equine veterinary practice
Authors: HALNAN C. R. E.
Published: April 2010

The prognostic use of karyotyping in equine breeding has been recommended since 1976. Specimens used and laboratory methods are described. The system of karyotype evaluation is explained together with a glossary of terms. The principal aberrations in horses are defined. The present state of knowledge in cytogenetics in horses is reviewed dealing with infertility in the mare, where sex chromosomes give clear indication of problems; the situation with respect fo anomalies found in stallions and hermaphroditism is explained coupled with recent concepts of chromosomal roles in reproduction. The future potential for the application of cytogenetics in equine practice is explained in regard to the advanced techniques and knowledge in the human parallel field. It is concluded that karyotyping is an essential tool in the evaluation of reproductive problems in practice and should be used more frequently in future.
Sequences of papillomavirus DNA in equine sarcoids
Authors: TRENFIELD KAREN , SPRADBROW P. B. , VANSELOW BARBARA
Published: April 2010

DNA was extracted from 14 equine sarcoids, electrophoresed and hybridised with a radioactively labelled probe of bovine papillomavirus type I (BPV 1) DNA under conditions of low stringency. Twelve sarcoids contained sequences of DNA that hybridised with the probe and that comigrated with BPV 2 DNA. The viral DNAs in four of these sarcoids differed from BPV 1 and BPV 2 DNA on restriction endonuclease analysis. One of four cell lines derived from sarcoids also contained BPV 1 related DNA. The results confirm the frequent presence in equine sarcoids of unintegrated papillomaviral DNA and suggest a role for papillomavirus infection in this disease.
Diurnal variation of dynamic compliance, resistance and viscous work of breathing in normal horses and horses with lung disorders
Authors: STADLER P. , DEEGEN E.
Published: April 2010

Dynamic compliance, airway resistance, viscous work and respiratory frequency were measured at intervals in horses over 12 h periods. Variation, daily averages and circadian patterns were recorded. Examinations were performed on 24 horses. They were divided into three groups: Normal horses, horses with chronic latent bronchitis and horses with manifest chronic obstructive pulmonary disease (COPD). Significant differences were found between the daily averages and the fluctuations when the normal group and the COPD group were compared. In most cases differences between all three groups were significant. A significant circadian rhythm for airway resistance was detected in diseased horses. It was also established that single measurements give an incomplete picture of lung function. As has been established in humans, analysis of fluctuations in respiratory mechanics may be of diagnostic value. The above results should be taken into account particularly in trials with bronchodilators in horses with COPD.
Isolation of Streptococcus pneumoniae from the respiratory tract of horses
Authors: BURRELL M. H. , MACKINTOSH M. E. , TAYLOR C. E. D.
Published: April 2010

Streptococcus pneumoniae was isolated from nasopharyngeal swabs and tracheal washings taken from Thoroughbred horses in training at three of four separate stables that were sampled during investigations into respiratory disease. The growth of Strep pneumoniae in culture was enhanced by an environment enriched with carbon dioxide. In one stable, five of 15 horses that were sampled repeatedly were found to carry the organism for at least four months. There was an apparent association between lower respiratory tract inflammatory disease and heavy growths (106 to 108 colony forming units/ml) predominantly of Strep pneumoniae or of that organism together with large numbers of Strep zooepidemicus obtained from tracheal washings. Twelve strains of Strep pneumoniae isolated from three stables were all of capsule Type 3. Only one strain, which was of capsule Type 9, was isolated from nose and throat swabs taken from 32 staff working in one of the stables and suggested an absence of cross infection between horses and their handlers in this instance.
Epidemiological features of 5009 cases of equine cryptorchism
Authors: HAYES H. M.
Published: April 2010

Data from 16 North American veterinary university teaching facilities, 5009 cryptorchid horses, were analysed using relative risk methodology. In five breeds (Thoroughbred, Standardbred, Morgan, Tennessee Walking horse and Arabian), cryptorchism was diagnosed significantly (P<0.05) less frequently than expected by their representation in the hospital population. Three breeds, (Percheron, American Saddle horse and American Quarterhorse), plus ponies (as a group) and crossbred horses were significantly over‐represented within the series. The over‐representation of Quarter‐horses was evident at each veterinary teaching facility. Other developmental defects and testicular tumours diagnosed in cryptorchid horses were presented. Analysis of the frequency of diagnosis of second anomalies among cryptorchids showed testicular hypoplasia to occur significantly more often, and inguinal and umbilical hernias less often, than expected (P<0.05).
Metabolic and hormonal responses to neuroleptanalgesia (etorphine and acepromazine) in the horse
Authors: ROBERTSON SHEILAH A.
Published: April 2010

Administration of etorphine and acepromazine to horses was associated with an increase in haematocrit, blood glucose, blood lactate and plasma non‐esterified fatty acids (NEFA). The rise in plasma NEFA was most striking following injection of the antagonist diprenorphine and could contribute to the production of cardiac arrhythmias. Plasma insulin was depressed at the end of surgery. These changes, plus profuse sweating, are indirect evidence of strong sympathetic stimulation. Plasma cortisol did not alter significantly due to wide individual variation. Venous blood pH fell, reflecting the rise in lactate and venous carbon dioxide tension.
Measurement of flunixin in equine inflammatory exudate and plasma by high performance liquid chromatography
Authors: HIGGINS A. J. , LEES P. , SHARMA S. C. , TAYLOR J. B.
Published: April 2010

An accurate and reliable method for the separation of flunixin from, and measurement in, equine inflammatory exudate and plasma by high performance liquid chromatography has been developed. Flunixin can be detected in concentrations as low as 0.05 μg/ml using an ultraviolet spectrophotometric detector at 285 nm. Samples were acidified with 2M hydrochloric acid and extracted with dichloromethane. The extract was evaporated and reconstituted in acetonitrile. Iminodibenzyl was used as Internal standard. The mean recovery of flunixin from plasma was 97.6±3.9 per cent. Particular advantages of the method are the short analysis time and ease of sample preparation. Data were obtained on the distribution of flunixin between plasma and acute inflammatory exudate following administration of a single intravenous dose of 1.1 mg/kg body weight flunixin meglumine. The drug was cleared more slowly from exudate than from plasma.
Air hygiene in stables 1: Effects of stable design, ventilation and management on the concentration of respirable dust
Authors: WEBSTER A. J. F. , CLARKE A. F. , MADELIN THERESA M. , WATHES C. M.
Published: April 2010

The concentration of fungal spores, the main constituents of respirable dust in stables, is determined by rates of release from fodder and bedding and rate of clearance, principally by ventilation. This paper outlines the principles that govern the application of natural ventilation to the control of air hygiene in barns and individual boxes for horses. When release rates are low, ventilation rates over four air changes per hour are satisfactory. Ventilation was satisfactory in individual boxes but usually unsatisfactory in barns and specific recommendations are made for improvement. Preliminary observations in stables with clean, well‐managed bedding revealed only small differences between straw, wood shavings and paper. In these circumstances hay tended to be the major source of respirable spores.
A technique for assessing hoof function in the horse
Authors: COLLES C. M.
Published: April 2010

This paper describes the application of foil strain gauges to the hoof wall, and the use of measuring equipment to monitor weightbearing and changes in hoof shape in shod and unshod horses. It concludes that the systems can detect hoof movement and that results are reproducible. It is also concluded that the use of a conventional nailed on iron shoe restricts flexion and spreading of the hoof wall at the ground surface, but has little effect on the degree of expansion of the heels of the foot.
Cervical spinal kinematics: a comparison between foals and adult horses
Authors: CLAYTON HILARY M. , TOWNSEND H. G. G.
Published: April 2010

A photographic method was used to measure axial rotation, dorsoventral flexion and extension and lateral bending at each intervertebral joint complex from the occiput to the first thoracic vertebra in spinal segments from 19 foals under 12 months of age and 14 horses over three years of age. Comparisons between the two groups showed that there was a general reduction in cervical spinal mobility with age. For the three types of movement at the eight joints tested, adults' mobility exceeded that of foals in only three cases (axial rotation and lateral bending at the A‐O joint, and lateral bending at C7‐T1). These differences were not significant (P>0.05). In the remaining 21 cases the amplitude of movement was greater in the foals, the differences being significant (P<0.05) in 16 cases. With regard to overall mobility of the cervical spine the foals exceeded the adults by 17.3 per cent for axial rotation, 22.0 per cent for dorsoventral flexion and extension and 18.7 per cent for lateral bending.
Glycosaminoglycans in horses with osteoarthritis
Authors: ALWAN W. H. , CARTER S. D. , BENNETT D. , EDWARDS G. B.
Published: April 2010

Horse articular cartilage glycosaminoglycans (GAGs) were measured in synovial fluids from 48 joints affected with osteoarthritis (OA), 22 normal joints, four joints with osteochondritis, three joints with traumatic arthritis and seven joints infected with bacteria. Serum and urine from individual horses were also examined for the presence of GAGs. High levels of GAGs were found in synovial fluids (SF) from horses with OA. In each case, the level was higher in the synovial fluid than in the serum or urine from the same horse. Horses with OA showed high GAG levels in SF, serum and urine compared to horses with normal and infected joints. High levels were also found in horses with osteochondritis and traumatic arthritis. Levels of synovial fluid GAG reflect cartilage destruction in arthritis and may be useful for monitoring disease progression in the equine species.
Identification of subclinical tendon injury from ground reaction force analysis
Authors: DOW S. M. , LEENDERTZ J. A. , SILVER I. A. , GOODSHIP A. E.
Published: April 2010

In this study a method of analysing ground reaction forces was developed to help in the diagnosis of subclinical flexor tendon injury. A Kistler force plate was used to obtain records from a population of Thoroughbreds in National Hunt training over a period of two years. Characteristic features of the force patterns generated were measured and shown to have low variance, both between horses and over a period of two racing seasons in animals that were sound throughout the trial. Specific changes in the loading pattern of the limb, which correlated with injury of the superficial digital flexor tendon, were identified from horses that sustained clinical injury during the study. Retrospective analysis showed that changes became apparent in the force patterns before this group of horses exhibited clinical lameness. This type of analysis provides an objective means of detecting tendon injury at an early stage.
Osteochondrosis in the horse — searching for the key to pathogenesis
Authors: JEFFCOTT L. B.
Published: April 2010

This paper reviews current developments in equine osteochondrosis complex and the clinical syndromes associated with it. Although the primary lesion has been defined as a failure of endochondral ossification, its definitive cause is unknown and appears to involve heredity, growth rate, nutrition, mineral imbalance, endocrinological dysfunction and biomechanical trauma. Despite the international importance of osteochondrosis in horses, surprisingly few controlled investigations have been performed on its pathogenesis. The studies that have been conducted suggest that local effects on differentiating growth cartilage are the key to a more complete understanding of the problem. Gaps in the current knowledge include in‐depth understanding of the life cycle of chondrocytes in growth cartilage, the process of mineralisation and the use of a standard experimental model for the induction of osteochondrosis. The ultimate goal of osteochondrosis research must be to prevent or reduce the incidence of the condition in horses.
The relationship between meteorological features and equine grass sickness (dysautonomia)
Authors: DOXEY D. L. , GILMOUR J. S. , MILNE E. M.
Published: April 2010

Local weather patterns associated with 15 outbreaks of equine grass sickness in eastern Scotland were studied. The majority showed a trend toward cooler drier weather associated with irregular ground frosts. This would not preclude the hypothesis that fungi might be connected with the aetiology of grass sickness.
The genetic basis of equine allergic diseases 1. Chronic hypersensitivity bronchitis
Authors: MARTI ELIANE , GERBER H. , ESSICH G. , OULEHLA J. , LAZARY S.
Published: April 2010

The genetic influence on chronic hypersensitivity bronchitis (CB) was investigated in families at two studs and among half‐siblings of three affected and three non‐affected sires at several farms. The family members at the two studs were born and raised under the same conditions, whereas the half‐siblings were kept individually under very different conditions and were exposed to various environmental factors. The diagnosis was based on long‐term observations and multiple clinical examinations at each of the two studs. In the half‐sibling group, the diagnosis was based on the individual history and on a thorough clinical examination. The history of all horses suggested the disease was caused by allergies (symptoms provoked by hay). Statistical analysis of the data in the first study showed that a greater percentage of off‐spring of two affected parents developed CB (9 of 13) than those with only one affected parent (23 of 48) and those with two healthy parents (5 of 29). The distributions of the affected offspring in these three categories (none, one or both parents affected) differed significantly (P<0.005) from what would have been expected without a genetic effect. The tendency to develop the disease was inherited equally from dams or sires. In the second stud fewer animals (n=42) were included in the study, but the results were similar. Parents without a history of CB produced off‐spring with a low incidence of disease (1 of 16) compared with a higher incidence among descendants of one or two affected parents (10 of 26; P=0.02). Half‐siblings descending from healthy sires had a lower incidence of disease than horses sired by affected stallions (P=0.02). In this group the quality of stabling also showed an effect on the condition of the horse (P<0.05). These results suggest that hypersensitivity CB in horses is a multifactorial disease with a rather strong genetic basis. There was no association with the major histocompatibility complex.
A comparison between the nutritive value of short‐cutting cycle, high temperature‐dried alfalfa and timothy hay for horses
Authors: CUDDEFORD D. , WOODHEAD AMANDA , MUIRHEAD RHONA
Published: April 2010

The objective was to evaluate the nutritive value of short‐cutting cycle, high temperature‐dried (SCCHTD) alfalfa compared to timothy hay. This was achieved by carrying out 4 times 4 Latin Square digestibility trial using 4 Thoroughbred (one three‐quarter Thoroughbred) horses (mean liveweight, 531 kg). The four dietary treatments were 0AA (timothy hay only), 33AA (0.33 alfalfa: 0.67 timothy hay), 67AA (0.67 alfalfa: 0.33 timothy hay) and 100AA (alfalfa only). Digestibility data were obtained by using acid‐insoluble ash to estimate apparent digestibility coefficients of nutrients. Kate of passage of the feedstuff was determined using chromium‐mordanted hay. Plasma triglyceride and cholesterol concentrations were estimated. The digestibilities of organic matter (0.63), energy (0.57) and crude protein (0.74) of the alfalfa were significantly (P<0.001) higher than those for the hay (0.45, 0.43 and 0.36 respectively). The fibre components of alfalfa and hay were digested to the same extent but the ether extract of alfalfa was less well digested. Alfalfa saponins had no consistently significant effects on plasma cholesterol and triglyceride values but may contribute to the negative digestibility of alfalfa ether extract. We conclude that SCCHTD alfalfa is of much higher nutritive value than timothy hay when fed to Thoroughbred horses.
A tracheal tube‐in‐tube technique for functional separation of the lungs in the horse
Authors: MOENS Y. , GOOTJES P. , LAGERWEIJ E.
Published: April 2010

The tube‐in‐tube technique for the functional separation of the lungs in intact anaesthetised adult horses is based on fibre‐optic‐guided left‐sided endobronchial intubation avoiding tracheostomy. It facilitates a valid separation of the two lungs despite variability in bronchial and carinal anatomy. No clinical complications that could be related to its use have been seen.
The response of equine cortical bone to loading at strain rates experienced in vivo by the galloping horse
Authors: EVANS G. P. , BEHIRI J. C. , VAUGHAN L. C. , BONFIELD W.
Published: April 2010

The behaviour of cortical bone under load is strain rate‐dependent, i.e. it is dependent on the rate at which the load is applied. This is particularly relevant in the galloping horse since the strain rates experienced by the bone are far in excess of those recorded for any other species. In this study the effect of strain rates between 0.0001 and 1 sec‐1 on the mechanical properties of equine cortical bone were assessed. Initially, increasing strain rates resulted in increased mechanical properties. Beyond a critical value, however, further increases in strain rate resulted in lower strain to failure and energy absorbing capacity. This critical rate occurred around 0.1 sec−1 which is within the in vivo range for a galloping racehorse. Analysis of the stress‐strain curves revealed a transition in the type of deformation at this point from pseudo‐ductile to brittle. Bones undergoing brittle deformation are more likely to fail under load, leading to catastrophic fracture and destruction of the animal.
Videoendoscopic evaluation of the mare's uterus: II. Findings in subfertile mares
Authors: BRACHER VERENA , MATHIAS SUSANNA , ALLEN W. R.
Published: April 2010

Videoendoscopy of the reproductive tract was performed in 87 Thoroughbred mares with histories of reduced fertility. During hysteroscopy samples for cytological, microbiological and histological examinations were obtained under visual control. Common findings in these broodmares included: (a) endometrial degeneration, as assessed by an uneven distribution or atrophy of endometrial folds and/or a scarred appearance of the endometrium (49 mares, 56%); (b) endometrial cysts of various sizes and locations within the uterus with the most common location being at the base of the uterine horns (48 mares, 55%); (c) fluid accumulation in the uterine lumen (28 mares, 32%). A few mares had transluminal adhesions (7 mares, 8%) and in 2 mares the adhesions appeared to obstruct one uterine horn completely. A solitary discrete lump was detected in the wall of the uterine body in one mare and the suspicion of it being a leiomyoma was confirmed histologically with the aid of a visually directed biopsy sample. Free intraluminal structures were present in the uterine lumen in 3 mares, including one inspissated blood clot and two suspected remnants of resorbing pregnancies.

Flexible biopsy forceps and scissors passed through the working channel of the endoscope were used to sever small thin adhesions, but this method proved inadequate for multiple adhesions or cysts. Solitary endometrial cysts were removed by means of conventional rigid biopsy forceps passed alongside the endoscope, although bleeding from the operation site usually limited this type of intervention.
Evaluation of local endobronchial antigen challenges in the investigation of equine chronic obstructive pulmonary disease
Authors: McGORUM B. C. , DIXON P. M.
Published: April 2010

Local transendoscopic endobronchial antigen challenge, which has proved to be a valuable clinical and research technique in the study of human pulmonary hypersensitivity, was evaluated in control and asymptomatic COPD ‐ affected horses.

Transendoscopic endobronchial challenges with phosphate‐buffered saline (PBS), Micropolyspora faeni extract at 60 and 600 μg/ml and mouldy hay extract elicited neutrophilic airway inflammatory responses in control (N=5–7) and asymptomatic COPD‐affected (N=5–7) horses, as determined by cytological examinations of bronchoalveolar lavage fluid (BALF) harvested from the challenged lung segments.

Endobronchial challenges with 600 μg M. faeni extract/ml induced a significant BALF neutrophilia only in horses with asymptomatic COPD, when compared with PBS challenges. However, as the BALF neutrophil ratios of COPD‐affected horses after this M. faeni challenge did not differ significantly from those of control horses, this finding has little clinical diagnostic value. The BALF neutrophilia induced in control and asymptomatic COPD‐affected horses by 60 μg M. faeni extract/ml and mouldy hay extract challenges was not significantly different from that induced by PBS challenge.

Endoscopically visible bronchial changes were observed in some of the control and COPD‐affected horses within 5 mins and at 5 h after PBS, M. faeni and mouldy hay extract challenges.

We conclude that this technique is of no value in the investigation of equine COPD.
An analysis of 75 cases of intestinal obstruction caused by pedunculated lipomas
Authors: EDWARDS G. B. , PROUDMAN C. J.
Published: April 2010

A retrospective study of 75 cases of pedunculated lipoma obstruction (PLO) of the intestine was conducted. Age, breed and sex distributions were compared to the non‐PLO colic population. Horses in the PLO group were significantly older than in the non‐PLO colic group (P<0.001). A significant increase in risk of PLO was associated with geldings (O.R. 2.32) and with ponies (O.R. 3.75). Of the 75 PLO cases analysed, 69 were strangulating, 70 involved small intestine and 5 involved small colon. Cases of strangulation obstruction tended to have lipomas originating distant to the mesenteric border of the intestine. The short‐term survival rate for PLO cases was 48%. Long‐term survival rate was 38%. Lipoma weight of some of the PLO group was compared with that from an asymptomatic pedunculated lipoma (APL) group. The two weight distributions were significantly different (P<0.001).
Cellular sources of proteolytic enzymes in equine joints
Authors: SPIERS SUE , MAY S. A. , BENNETT D. , EDWARDS G. B.
Published: April 2010

Isolated equine blood and articular cells were investigated for proteolytic enzyme production by means of gel filtration and analysis on 14C‐acetylated collagen and casein substrates. Significant amounts of collagenase and caseinase activity were produced by cultured synoviocytes stimulated with equine interleukin 1, although large amounts of collagenase also originated from neutrophils.
Immunohistochemical localisation of steroidogenic enzymes and phenylethanolamine‐N‐methyl‐transferase (PNMT) in the adrenal gland of the fetal and newborn foal
Authors: HAN X. , FOWDEN ABIGAIL L. , SILVER MARIAN , HOLDSTOCK NICOLA , McGLADDERY A. J. , OUSEY JENNIFER C. , ALLEN W. R. , ROSSDALE P. D. , CHALLIS J. R. G.
Published: April 2010

An increase in fetal adrenal cortisol output signals the onset of parturition in many animal species but, in the fetal horse, plasma concentrations of cortisol remain low for much of late pregnancy, with a rise occurring only very close to the time of birth (term 320–360 days). Immunohistochemistry was used to determine the localisation and changes in distribution of key steroidogenic enzymes for cortisol production; P450SCC, P450C17 and 3β‐hydroxysteroid dehydrogenase (3βHSD) in adrenal tissue from fetal and newborn horses and these findings were correlated with the appearance of immunoreactive (IR)‐phenylethanolamine‐N‐methyl‐transferase (PNMT), a cortisol‐dependent enzyme. Five micron sections of adrenal tissue from fetuses at Day 100–156 (n=5), Day 244–295 (n=8), greater than Day 300 (n=4) and from newborn foals (n=6), were stained using specific antibodies and the avidin‐biotin‐peroxidase technique. All 3 steroidogenic enzymes were present by Day 150, but in less than 20% of the cortical cells. By late gestation the steroidogenic enzymes were present in approximately 30% of the cells, but the distribution varied. P450SCC and P450C17 predominated in cortical cells proximal to the medulla; 3βHSD was present throughout the cortex, but more in the zona fasciculata. In foals after birth, IR‐3βHSD and IR‐P450SCC had increased substantially throughout the adrenal cortex, and IR‐P450C17 was present in most cells of the presumptive zonae fasciculata and reticularis. IR‐PNMT was localised to nuclei of scattered medullary cells at the medullary‐cortical interface by Day 150. It was present in the cytoplasm of a band of cells at the medullary‐cortical interface by Day 310 and this pattern persisted into the post natal period. This study suggests that the low cortisol output of the adrenal of the fetal horse is associated with relatively poor expression of steroidogenic enzymes during most of fetal life, but that the presence of these enzymes increases rapidly just before or after birth. Differentiation of the IR‐PNMT containing cells preceded complete adrenocortical expression of the enzymes on the cortisol biosynthetic pathway. This pattern of distribution is quite different from that seen in fetal adrenal tissue of other species such as the sheep.

This work provides further understanding of the part played by the equine fetal adrenal gland and placenta in the pathway of steroid metabolism leading up to parturition and associated processes of maturation in the fetal foal. These represent the basis of clinical conditions of prematurity and dysmaturity in the horse.
Role of navicular bone shape in the pathogenesis of navicular disease: a radiological study
Authors: DIK K. J. , van den BROEK J.
Published: April 2010

From progeny lists of 30 Dutch Warmblood sires, 586 3‐year‐old females by these stallions were randomly selected, each progeny group aimed at 20 animals for statistical reasons. The front feet of the sires and female progeny were examined radiographically using lateromedial and dorsopalmar upright pedal projections. The radiological features associated with navicular disease were classified 0–4 using a standardised classification, grades 3 and 4 representing the more severe changes. The shape of the proximal articular border of the navicular bone outlined on the dorsopalmar view was classified 1–4: l=concave; 2=undulating; 3=straight; 4=convex. A significant shape‐grade association was found, the highest grades 3 and 4 incidence associated with shape 1 and the lowest grades 3 and 4 incidence demonstrated by shape 4. In shapes 1 and 2, navicular bones grades 3 and 4 features were mainly characterised by inverted flask‐shaped channels. In shape 3, navicular bones grades 3 and 4 were dominated by enthesiophytes. These findings indicate an apparent shape predisposition to radiological changes associated with navicular disease. The shape of the navicular bone in the offspring was on average the same as the sire, indicating an hereditary element in navicular bone shape.
The significance of routine radiographic findings with respect to subsequent racing performance and longevity in Standardbred trotters
Authors: JØRGENSEN H. STORGAARD , PROSCHOWSKY H. , FALK‐RØNNE J. , WILLEBERG R. , HESSELHOLT M.
Published: April 2010

A retrospective cohort study was made of the racing performance of trotters which had been subjected routinely to radiography before they started training and racing. Sixty‐one per cent (148) of the 243 horses, foaled in 3 consecutive years, had one or more abnormal findings categorised into 5 relevant groups based on radiography, of which osteochondrosis (OCD) was the most specific diagnosis. Parameters used to reflect racing performance were: proportion of horses starting in races, number of starts per year, earnings per year, earnings per start and racing longevity. No significant association between the presence or type of radiological abnormalities and the subsequent performance and longevity could be found. Horses with multiple lesions, however, had a tendency to lower earnings and poorer survival than horses with single lesions.
Ultrasonographic examination of the proximal scutum in the horse
Authors: DENOIX J. M. , BUSONI VALERIA , OLALLA MARIA‐JOSÉ
Published: April 2010

Normal and abnormal ultrasonographic images are presented of the proximal scutum (proximal sesamoid bones and palmar ligament) in the horse. Comparison between anatomical sections, MRI (magnetic resonance imaging) and ultrasound scans enabled the authors to establish the normal ultrasonographic anatomy of the palmar fetlock. Nine cases of proximal scutum injuries were identified ultrasonographically, of which 4 are illustrated. On normal limbs, the facies flexoria of the proximal sesamoid bones appeared as a thin and regular hyperechoic line and the palmar ligament was regularly echogenic. Lesions of the proximal scutum, that could be documented uitrasonographically, included rupture of the palmar ligament, avulsion fractures of the proximal sesamoid bones and palmar ligament desmopathy. Thinning or degeneration of the palmar ligament, concurrent with osteolysis of the proximal sesamoid bones, were indicative of palmar ligament enthesopathy. Ultrasonographic examination provided essential information for an accurate diagnosis of proximal scutum damage.
Laparoscopic intra‐abdominal ligation and removal of cryptorchid testes in horses
Authors: FISCHER A. T. , VACHON ANNE M.
Published: April 2010

Laparoscopic intra‐abdominal ligation and removal of cryptorchid testes in horses was evaluated retrospectively in 50 horses that underwent the procedure between 1991 and 1996. Sixty‐one cryptorchid testes were removed by one of the following methods; the use of 1) an endoscoping stapling and transection device, 2) an endoscopic clipping device, 3) an endoscopic ligating loop. Monopolar electrosurgery was combined with these methods to facilitate coagulation and cutting of tissue. In 8 horses, 9 testes were retained between the internal and external inguinal rings. The inguinal testes were removed by cutting the internal inguinal ring and bringing the testis back into the abdomen for removal. No attempt was made to close the internal inguinal ring. The most frequently employed and most cost effective method for laparoscopic intra‐abdominal removal of cryptorchid testes in this study was the combined use of an endoscopic ligating loop and monopolar electrosurgery. One intra‐operative complication (perforation of the small intestine) occurred and was dealt with successfully. One horse developed a fever attributed to upper respiratory tract infection post operatively and was treated successfully with antibiotic.

Intra‐abdominal ligation and transection of cryptorchid testes is an effective method for cryptorchid castration. This technique minimises the loss of insufflation, allows inspection of the cut tissue for haemorrhage and offers secure closure of the abdominal wall preventing inguinal herniation and excellent visualisation of the cryptorchid testis.
Effect of copper supplementation on copper status of pregnant mares and foals
Authors: PEARCE S. G. , GRACE N. D. , WICHTEL J. J. , FIRTH E. C. , FENNESSY P. F.
Published: April 2010

Pregnant Thoroughbred mares (n = 21) were grazed on tall fescue pasture containing 4.4–8.6 mg Cu/kg dry matter (DM). Twelve mares were supplemented with approximately 0.5 mg Cu/kg liveweight (LW)/day as copper sulphate for the final 13–25 weeks gestation. Plasma copper concentration declined during the third trimester for all mares and was not affected by copper supplementation. Liver copper concentration of mares and foals was determined when the foals were 4–10‐days‐old. Copper supplementation of the mares tended to increase mare liver copper concentration (P<0.08) and increased foal liver copper concentration (P<0.01). There was a significant relationship between mare and foal liver copper concentration (P<0.001, r2= 0.7). Increasing the copper intake of mares is effective in enhancing the copper status of foals.
Tenosynovitis associated with longitudinal tears of the digital flexor tendons in horses: A report of 20 cases
Authors: WRIGHT I. M. , McMAHON P. J.
Published: April 2010

The paper describes a series of cases with longitudinal tears in the superficial or deep digital flexor tendons within the digital flexor tendon sheath. This appears to be a previously unreported condition. Twenty cases are described, one horse was affected bilaterally. Nineteen defects involved the deep digital flexor tendon and in 2 horses themanica flexoriaof the superficial digital flexor tendon was torn. All affected horses were lame and there was marked distension of the digital flexor tendon sheaths. Ultrasonography revealed nonspecific signs of chronic tenosynovitis but not the cause. Diagnosis was established by tenoscopy in 9 cases and by open surgical exploration in the remainder. In 7 limbs, the deep digital flexor tendon lesions were treated by removal of the torn fibrils under tenoscopic control. In the remaining cases they were removed and the defects were repaired with absorbable suture material. Wound closure in all open cases included repair of the palmar/plantar annular ligament. Eleven horses became sound and returned to work, 3 improved but were lame on returning to work and 2 horses did not improve following treatment. At the time of reporting, 4 horses are sound and in controlled ascending exercise regimes.

It is concluded that longitudinal tears of the digital flexor tendons should be considered in the differential diagnosis of tenosynovitis of the digital flexor tendon sheath. The results presented suggest that accurate diagnosis and specific treatment justify surgical investigation.
Characterisation of lymphocyte subpopulations in the skin and circulation of horses with sweet itch (Culicoides hypersensitivity)
Authors: McKELVIE JOANNE , FOSTER A. P. , CUNNINGHAM FIONA M. , HAMBLIN ANNE S.
Published: April 2010

Circulating lymphocyte numbers are elevated in horses with the allergic skin disease sweet itch and skin lesions are typified by an infiltrate of eosinophils and mononuclear cells, the latter of which have not been fully characterised. The aim of the present study was to characterise the lymphocyte subpopulations in the circulation and skin of ponies with sweet itch by flow cytometry and a newly developed modified alkaline phosphatase immunohistochemical technique. Sweet itch ponies were found to have significantly greater numbers of circulating CD5+ and CD4+ T‐lymphocytes than normal animals. Increased numbers of CD3+ T‐lymphocytes, most of which were CD4+, and eosinophils were present in the skin of these animals following intradermal injection of a Culicoides antigen extract (97 ± 21 vs. 449 ± 49 CD3+ T‐lymphocytes/mm2 in deep dermis of vehicle vs. antigen injected sites; 83 ± 8% CD4+ T‐lymphocytes at antigen injected site). T‐lymphocytes, which are thought to be important in the pathogenesis of human allergic skin disease, may therefore contribute to the development of sweet itch lesions via the release of cytokines which can cause eosinophil accumulation and activation. An understanding of the pathology of this disease may lead to a more rational approach to therapy.
Infection of endothelial cells with Equine herpesvirus‐1 (EHV‐1) occurs where there is activation of putative adhesion molecules: a mechanism for transfer of virus
Authors: SMITH D. J. , HAMBLIN A. S. , EDINGTON N.
Published: April 2010

Evidence is presented to show that activation of endothelial and leucoyte adhesion molecules is a key step in transferring virus from infected leucocytes; and determines the restricted tissue tropism. A range of tissues from 2 experimentally infected mares in late pregnancy at 4 and 8 days after infection with EHV‐1 were compared with those from normal pregnant and nonpregnant mares. Rabbit antisera to equine activated endothelial cell molecules were used to identify which tissues expressed these molecules in normal nongravid and gravid mares, and to investigate whether the range of tissues was altered in pregnant mares as a consequence of infection. The results indicated that the endothelium of the pregnant reproductive tract did express these molecules. In the 2 pregnant mares infected with EHV‐1, the endothelial cells in the nasal mucosa also expressed these activated endothelial cell molecules. Therefore, the sites expressing these molecules closely correlated with those where virus infection of endothelial cells has been described and is consistent with experimental in vitro data, indicating that expression of these molecules is an essential stage in the transference of virus from leucocytes to endothelial cells.
Secondary ion mass spectrometry characterization of anomalous behavior for low dose ion implanted phosphorus in silicon
Authors: Penley C. , Stevie F. A. , Griffis D. P. , Siebel S. , Kulig L. , Lee J.
Published: April 2010

Significant changes over time have been observed in surface and near surface phosphorus concentration for low dose phosphorus implants measured using secondary ion mass spectrometry (SIMS) with cesium bombardment. These variations in concentration affect the ability to make reproducible dose measurements. Phosphorus measurements have been documented for samples from wafers kept at ambient conditions and also for those stored in a range of other conditions including heat, high humidity, low humidity, and liquid nitrogen. An initial study of wafers ion implanted over a range of doses showed that the change in the surface phosphorus concentration was most apparent for the lowest phosphorus dose (1×1012 atoms/cm2) and that heating the sample resulted in the most significant change (increase in almost three orders of magnitude) in apparent surface P concentration. Only the specimens stored at liquid nitrogen temperature showed no change in P surface concentration. SIMS analysis conditions were optimized and a second set of analyses were performed on wafers that included different wafer processing (thicker surface oxide, preamorphization, and anneal) in an effort to reduce the change in surface phosphorus. Significant improvement in P dose reproducibility was noted for the wafer that had been implanted through a 5 nm oxide and stored in dry conditions.
Cooperation Between Translating Ribosomes and RNA Polymerase in Transcription Elongation
Authors: Proshkin Sergey , Rahmouni A. Rachid , Mironov Alexander , Nudler Evgeny
Published: April 2010

Transcription and Translation in Train

In bacteria, translation of messenger RNA into proteins by the ribosome usually begins soon after the ribosome binding site emerges from RNA polymerase. Now there is evidence for direct coupling between transcription and translation in bacteria.
Proshkin et al.
(p.
504
; see the Perspective by

Roberts

) show that the trailing ribosome controls the rate of transcription by preventing RNA polymerase from spontaneous backtracking, which allows precise adjustment of transcriptional yield to translational needs under various growth conditions.
Burmann et al.
(p.
501
; see the Perspective by

Roberts

) provide a potential mechanism for coupling by showing that the transcription factor NusG, which binds RNA polymerase through its amino-terminal domain, competitively binds either a ribosomal protein or the Rho transcription termination factor through its carboxy-terminal domain. Rho binding might occur after release of the ribosome from messenger RNA, thus linking termination of transcription and translation.
Molecular Basis of Alternating Access Membrane Transport by the Sodium-Hydantoin Transporter Mhp1
Authors: Shimamura Tatsuro , Weyand Simone , Beckstein Oliver , Rutherford Nicholas G. , Hadden Jonathan M. , Sharples David , Sansom Mark S. P. , Iwata So , Henderson Peter J. F. , Cameron Alexander D.
Published: April 2010

Triangulating to Mechanism

Cellular uptake and release of a variety of substrates are mediated by secondary transporters, but no crystal structures are known for all three fundamental states of the transport cycle, which has limited explanations for their proposed mechanisms.

Shimamura
et al.

(p.
470
) report a 3.8-angstrom structure of the inward-facing conformation of the bacterial sodium-benzylhydantoin transport protein, Mhp1, complementing the other two available structures. Molecular modeling for the interconversions of these structures shows a simple rigid body rotation of four helices relative to the rest of the structure in which the protein switches reversibly from outward- to inward-facing.
Complexity and Diversity
Authors: Doebeli Michael , Ispolatov Iaroslav
Published: April 2010

A Little Selection for a Lot of Rarity

Studies on how selection works have tended to focus on the effect of a single trait. This necessarily means that rare alleles that can be acted on by selection appear to experience high levels of frequency-dependence selection. However, selection may act on multiple traits at any one time.
Doebeli and Ispolatov
(p.
494
) present a theoretical framework examining how multiple rare traits can persist and potentially drive speciation. The s show that only low levels of frequency-dependent selection are needed to explain the observed high levels of allelic diversity in nature.
Sign Flips and Spin Fluctuations in Iron High-
T
c
Superconductors
Authors: Hoffman Jennifer E.
Published: April 2010

The symmetry of electron-pairing interactions in iron-based superconductors suggests a shared spin-mediated pairing mechanism with the cuprate family.
Human Ancestor Caught in the Midst of a Makeover
Authors: Gibbons Ann
Published: April 2010

Last week, some early members of
Homo erectus
got a new look at the annual meeting of the American Association of Physical Anthropologists, morphing from tall, slender-hipped individuals that looked a lot like us into shorter, broader hominins.
Congress Moves Toward Strengthening EPA's Hand on Chemical Safety
Authors: Stokstad Erik
Published: April 2010

If passed, two bills in Congress would require chemical companies to provide much more safety data to the U.S. Environmental Protection Agency (EPA). The proposed legislation also expands EPA's role in determining safety, which some say could drive advances in toxicological research.