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The purpose of this study was to determine the reliability of B-mode ultrasound measured muscle thickness of the longissimus dorsi muscle in horses. Thirteen Thoroughbreds (5 colts, 5 fillies and 3 mares) had their muscle thickness measured by B-mode ultrasound at four sites; the longissimus dorsi (LD at 30%, 50% and 70% of back length) and extensor carpi radialis (ECR) muscle on two separate test sessions (T1 and T2). Paired t-tests revealed that there was no systematic bias in any of the muscle thickness measures. There were high intraclass correlation coefficients between the LD muscle thickness at 30, 50 and 70% of back length obtained at the T1 and T2 measurements (range: 0.95-0.98). The ECR muscle thickness was positively correlated to body weight and fat-free mass while LD muscle thickness at 50% and 70% of back length did not correlate to body dimensions. Our results suggest that ultrasound measures of muscle thickness of the LD and ECR muscles are reliable and repeatable when taken with the horse standing in a relaxed and evenly balanced position.

Summary Reason for performing study: Older horses have an increased risk of hyperthermia due to impaired cardiovascular function. While many studies have investigated thermoregulation in horses during exercise, none have investigated the effects of ageing. Objective: To test the hypothesis that there is a difference in thermoregulation during exercise and plasma volume (PV) in young and old horses. Methods:Study 1: 6 young (Y, 7.7 ± 0.5 years) and 5 old (O, 26.0 ± 0.8 years) unfit Standardbred mares (507 ± 11 kg, mean ± s.e.) ran on a treadmill (6% grade, velocity calculated to generate a work rate of 1625 watts) until core temperature reached 40°C. Core (CT), skin (ST), rectal temperature (RT) and heart rate (HR) were measured every min until 10 min post exertion. Packed cell volume (HCT), lactate (LA) and plasma protein (TP) were measured in blood samples collected before, at 40°C and every 5 min until 10 min post exercise. Sweat loss was estimated using bodyweight. Study 2: Plasma volume was measured in 26 young (8.2 ± 0.7 years) and 8 old (26.6 ± 0.7 years) Standardbred mares (515 ± 12 kg) using Evans Blue dye. Pre-exercise blood (rBV) and red cell (rRCV) volumes were calculated using PV and HCT. Data analysis utilised repeated measures ANOVA and t tests and data are expressed as mean ± s.e. Results: Old horses reached 40°C faster (998 ± 113 vs. 1925 ± 259 s; P 0.05) post exercise. Age did not alter (P>0.05) CT, ST, RT, LA, HCT or TP. Plasma volume was greater in Y vs. O horses (P

Summary The purpose of the present study was to determine whether the training-induced hypervolemic response seen in the horse is associated with aldosterone-mediated renal mechanisms affecting sodium conservation during the first days of training. Five healthy, Standardbred mares (weight 450–500 kg, age 4–8 years) that were unfit, but accustomed to running on the treadmill, were used to test the hypothesis that repeated submaximal exercise would alter plasma aldosterone (ALDO) concentration and renal excretion of electrolytes in horses within the first 3 days of training. The experiment consisted of a 2 week housing equilibration period followed by a 1 week control period and a 3 day exercise training period (30 min/day at 60% VO2max). During control, ALDO and renal fluid and electrolyte losses were measured for 24 h on 3 separate days. Renal function (urine volume [UV], 24 h excretion of Na+, K+ and CI- [UNA+V, UK+V, UClV], clearance of Na+ [CNa+], K+ [CK+] and Cl− [CCl-], creatinine [CCr], osmotic substances [Cosm], and solute-free water [FWC], and the fractional excretion of Na+, K+ and Cl−) and ALDO were measured for an additional 3 consecutive days during the training period. There were no differences (P>0.05) in any variable during the control period. Plasma volume increased (+18.7%, P

Summary It has long been known that body mass and, more specifically, lean body mass are strongly correlated with maximal oxygen uptake (VO2max) in man and animals. However, there are no data to date describing this phenomenon in the horse. The purpose of this paper is to examine the relationship between body composition and VO2max in the horse. Twenty-three healthy and unfit Standardbred mares performed an incremental exercise test (GXT) to measure VO2max. Rump fat thickness (RTH), a measure of fat covering, was measured using B-mode ultrasound. Plasma volume, total blood volume and red cell volume were determined, using the Evan's Blue dye dilution technique and packed cell volume. VO2max was correlated with body mass (r = 0.541; P

The purpose of the study was to determine whether 12 weeks of exercise training would affect plasma glucose and plasma insulin concentrations in young and older Standardbred mares. Eighteen healthy, unfit mares representing 3 age groups were used: young (Y = 6.8 +/- 0.4 years; n = 6), middle-aged (MA = 15.2 +/- 0.4; n = 6), and old (O = 27.0 +/- 0.2; n = 6). Pre- and post-training incremental exercise tests (GXT) were performed to measure plasma glucose and insulin concentration from immediately after, until 120 min postexercise. Training consisted of exercise 3 days/week (weeks 1-8) and 4 days/week (weeks 9-12) at a submaximal intensity (approximately 60% of pretraining HRmax) for approximately 30 min/day. Old mares had lower levels of glucose after the GXT when compared to Y and MA mares (P0.05). There was also a time-by-age interaction (P = 0.003) in that, at 120 min post-GXT, glucose levels had not returned to pre-exercise values. Plasma glucose concentrations, in response to acute exercise, were not altered by training for any age group (P0.05). Prior to exercise training, O mares had higher plasma insulin compared to Y and MA mares at 120 min postexercise (P0.05), and insulin was also elevated in O mares compared to all other time points at 120 min post-GXT (P0.05). Training resulted in increased plasma insulin concentrations at 120 min post-GXT in all age groups (P0.05). In conclusion, age affected glucose and insulin responses to acute exercise prior to and after 12 weeks of exercise training. With regards to insulin, 12 weeks of exercise training resulted in a postexercise rebound hyperinsulinaemia, which may be related to an increased need for glycogen repletion in the muscle. These factors are important in considering the ability of an older horse to tolerate exercise.

Clenbuterol is a beta(2)-agonist and potent selective bronchodilator that is used to treat bronchospasm in the horse. The drug is normally administered to horses orally as a syrup formulation. Once absorbed into the systemic circulation, clenbuterol has the potential to cause many side effects, including a repartitioning effect and major alterations in cardiac and skeletal muscle function. Recent studies have also reported that clenbuterol can affect bone and the immune, endocrine and reproductive systems. A great deal of information has been published on the beneficial effects of short term therapeutic doses of clenbuterol on the equine respiratory system, although there is limited information about chronic administration, particularly since this has been associated with adverse physiological effects on other systems. This review summarizes the relevant understanding of clenbuterol for clinicians and horse owners who may administer this drug to pleasure and performance horses.

The authors describe a novel 4-month clinical placement in neurosciences intensive care medicine (NICM) undertaken in the first specialty registrar (ST1) year of neurosurgical training as part of a clinical neurosciences themed training year. Neurosurgery is unique among British surgical specialties in having pioneered themed early years in run-through training to replace basic surgical training in general surgical specialties as part of Modernising Medical Careers. After describing events leading to the new neurosurgical training, the knowledge, skills and attitudes acquired in NICM are highlighted alongside discussion of logistic aspects and future directions from an inaugural experience.

There are limited data on age-related changes in body composition or skeletal muscle in the horse. Therefore, the purpose of this study was to investigate any differences in muscle myosin heavy chain (MHC) and body composition associated with aging. Twenty-three young (4-8 years) and eight old (20+ years) unfit Standardbred mares were evaluated. Rump fat thickness was measured using B-mode ultrasound and per cent body fat (% fat) was calculated. Needle muscle biopsies were obtained from right gluteus medius muscle. MHC composition was determined via sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Three MHC isoforms were subsequently identified as type I, type IIA, and type IIX and quantified using a scanning and densometric system. There were no significant differences (p0.05) between old and young mares in fat (%) (19.0+/-6.4 vs 20.5+/-5.4), fat mass (kg) (102.3+/-39.9 vs 106.9+/-37.1), or body weight (kg) (529.4+/-34.9 vs 512.7+/-57.7). However, the old mares had significantly (p0.05) greater lean body mass than the young mares (427.1+/-24.5 vs 405.7+/-37.9). Aged mares had significantly (p0.05) less type I (7.8+/-2.9% vs 12.1+/-4.4%) and IIA (27.8+/-7.1% vs 36.1+/-9.5%) fibres than the young group but more type IIX (64.6+/-4.7% vs 51.8+/-11.1%). The MHC data are consistent with the age-related changes seen in other species.

The purpose of this study was to examine changes in myosin heavy chain (MHC) composition due to chronic clenbuterol administration with or without exercise in mares. Unfit Standardbred mares (aged 10+/-3 years) were divided into four groups: clenbuterol (2.4 micro/kg BW twice daily) plus exercise (3 days/week for 20 min at 50% VO(2max); CLENEX; n=6), clenbuterol only (CLEN; n=6), exercise only (EX; n=5), and control (CON; n=6). Muscle biopsies were obtained from gluteus medius muscle before and after the eight-week training/administration period. MHC composition was determined via SDS gel electrophoresis and quantified using a scanning and densometric system. CLENEX and CLEN exhibited significant (P

Clenbuterol is a β2-adrenoceptor agonist primarily used for treating bronchospasm and alleviating the symptoms of chronic obstructive pulmonary disease (COPD) in the horse. In other species (rats, mice, sheep, and cattle), chronic high doses of clenbuterol (typically in the milligram per kilogram body weight range) has been shown to cause a muscle directed protein anabolic response. Clenbuterol can also modify muscle fibre composition and therefore potentially affect muscle function. This has implications for the performance of exercising horses being treated with therapeutic doses of clenbuterol (typically in the microgram per kilogram body weight range) for bronchospasm or COPD. It is not known whether clenbuterol treatment affects muscle fibre function in horses. The purpose of this study was to examine the effects of a therapeutic dose of clenbuterol, with and without exercise, on the contractile activation characteristics of single membrane permeabilized fibres prepared from muscle biopsies. We tested the hypothesis that therapeutic treatment with clenbuterol would not affect muscle fibre function. Unfit Standardbred mares were treated for 8 weeks with; clenbuterol (2.4 μg/kg twice/day, 5 days/week) plus exercise (20 min at 50% \(\dot V\)O2max 3 d/wk; CLENEX), clenbuterol only (CLEN), or exercise only (EX). Muscle biopsies were taken from the gluteus medius muscle before and after treatment and stored in a glycerol-based solution to prepare permeabilized muscle fibres. The force–pCa relationship for fibres from CLEN horses was steeper (P < 0.05) indicative of greater cooperative interactions within the thin filament, however, fibre sensitivity to Ca2+ was unchanged. In contrast, the steepness of the force–pCa relationship was not changed in fibres from EX and CLENEX horses and Ca2+ sensitivity was also unaffected. Rigor force, activation in the absence of ATP, was not affected by any treatment indicating an approximately equivalent number of participating cross-bridges during activation. The results indicate that a therapeutic dose of clenbuterol to Standardbred horses does not affect the Ca2+-activated contractile characteristics of isolated muscle fibres.

Purpose: The purpose of this 8-wk study was to examine the effect of therapeutic levels of clenbuterol on aerobic performance and hemodynamics associated with exercise. Methods: Twenty-three unfit Standardbred mares were divided into four experimental groups, clenbuterol (2.4 μg.kg -1 body weight twice daily) plus exercise (20 min at 50% VO 2max ; CLENEX; N = 6), clenbuterol only (CLEN; N = 6), exercise only (EX; N = 5), and control (CON; N = 6). All horses performed an incremental exercise test (GXT) to measure maximal oxygen consumption (VO 2max ), blood lactate concentration, total plasma protein concentration, and hematocrit. Plasma volume, heart rate, right ventricular pressure (RVP), and pulmonary artery pressure (PAP) were measured before and after the treatment/training. Each horse also performed an exercise capacity test (ECT) in which they ran at their pretreatment VO 2max speed until exhausted. Results: There were no significant changes in blood lactate, total protein, or hematocrit for any group during either the GXT or ECT. CLENEX decreased (P < 0.05) VO 2max (-6.2%) and velocity to VO 2max (-10.0%), whereas both CLENEX and CLEN decreased (P < 0.05) in time to exhaustion (-20.5 ± 4.7 and -20.9 ± 5.6%). EX alone increased (P < 0.05) VO 2max (+6.5%), velocity to VO 2max (+10.0%), velocity to produces lactate concentration of 4 mmol (+13.5%), and time to exhaustion (+32.3 ± 15.0%). Plasma volume was altered (P < 0.05) in CLENEX (-10%) and EX (+27%) but not in CLEN. Posttest recovery HR was higher (P < 0.05) at 2 min post-GXT in the CLENEX, CLEN, and CON compared with their pretest values; RVP remained elevated at 2 min of recovery in the CLEN and CON groups; however, in the EX, recovery HR and RVP had returned to pre-GXT levels by 2 min of recovery. Conclusions: These data suggest that the combined effect of therapeutic levels of clenbuterol and training decrease aerobic performance and that the resultant reduction in plasma volume may affect improvements in cardiovascular function during recovery normally seen with exercise training.

The objective of the present study was to measure plasma endothelin-1 (ET-1) at rest and during exercise in the horse. Six healthy, Standardbred and Thoroughbred mares (5.3+/-0.8 years; 445.2+/-13.1 kg) which were unfit, but otherwise accustomed to running on the treadmill, were used in the study. Plasma ET-1 concentrations were measured using a commercially available radioimmunoassay kit. Horses performed three trials: a standing control (CON) trial where blood was collected from the jugular vein every minute for 5 min; a graded exercise test (GXT) where blood samples were collected at the end of each 1 min step of an incremental exercise test; and a 15 min submaximal (60% VO(2max)) steady-state exercise test (SST) where blood samples were collected 1 min before, immediately after, and at 2 min, 10 min and 20 min post-exercise. Plasma ET-1 concentration did not change (P0.05) during the CON trial where it averaged 0.18+/- 0.03 pg/mL (mean+/-SE). Surprisingly, plasma ET-1 concentration did not change during the GXT trial where it averaged 0.20+/-0.03 pg/mL. There were no differences between the mean concentrations obtained in either trial (P0.05). Plasma ET-1 concentrations were, however, significantly elevated (P0.05) immediately following exercise and at 2 min post-exercise in the SST. Post-exercise plasma ET-1 concentrations returned to baseline (P0.05) by 10 min of recovery. Together, these data may suggest that ET-1 concentrations are altered in response to an exercise challenge.

PURPOSE Chronic administration of pharmacological levels of beta2-agonists have been shown to have toxic effects on the heart; however, no data exist on cardiac function after chronic clenbuterol administration. The purpose of this study was to examine the effect of therapeutic levels of clenbuterol on cardiac performance. METHODS Twenty unfit Standardbred mares were divided into four experimental groups: clenbuterol (2.4 microg.kg(-1) twice daily 5 d.wk(-1)) plus exercise (20 min at 50% .VO(2max)) (CLENEX; N = 6), clenbuterol (CLEN; N = 6), exercise (EX; N = 4), and control (CON; N = 4). M-mode and two-dimensional echocardiography (2.5-MHz sector scanner transducer) were used to measure cardiac size and function before and immediately after an incremental exercise test, before and after 8 wk of drug and/or exercise treatments. RESULTS After treatment, CLENEX and CLEN demonstrated significantly higher left ventricular internal dimension (LVD) at end diastole (+23.7 +/- 4.8%; +25.6 +/- 4.1%), LVD at end systole (+29.2 +/- 8.7%; +40.1 +/- 7.9%), interventricular septal wall thickness (IVS) at end diastole (+28.9 +/- 11.0%; +30.7 +/- 7.0%), IVS at end systole (+29.2 +/- 8.7%; +40.1 +/- 7.9%), and left ventricular posterior wall systolic thickness (+43.1 +/- 14.%; +45.8 +/- 14.1%). CLENEX and CLEN had significantly increased aortic root dimensions (+29.9 +/- 6.1%; +24.0 +/- 1.7%), suggesting increased risk of aortic rupture. CONCLUSION Taken together, these data indicate that chronic clenbuterol administration may negatively alter cardiac function.

The purpose of this study was to examine the effect of therapeutic levels of clenbuterol, with and without exercise training, on body composition. Twenty-three unfit Standardbred mares were divided into four experimental groups: clenbuterol (2.4 μg/kg body wt twice daily) plus exercise (ClenEx; 20 min at 50% maximal oxygen consumption 3days/wk; n = 6), clenbuterol only (Clen; n = 6), exercise only (Ex; n = 5), and control (Con; n = 6). Rump fat thickness was measured at 2-wk intervals by using B-mode ultrasound, and percent body fat (%fat) was calculated by using previously published methods. For Ex, body fat decreased ( P < 0.05) at week 4 (−9.3%), %fat at week 6 (−6.9%), and fat-free mass (FFM) increased ( P < 0.05) at week 8 (+3.2%). On the other hand, Clen had significant changes in %fat (−15.4%), fat mass (−14.7%), and FFM (+4.3%) at week 2. ClenEx had significant decreases in %fat (−17.6%) and fat mass (−19.5%) at week 2, which was similar to Clen; however, this group had a different FFM response, which significantly increased (+4.4%) at week 6. Con showed no changes ( P > 0.05) in any variable at any time. These results suggest that exercise training and clenbuterol have additive effects with respect to %fat and fat mass but antagonistic effects in terms of FFM. Furthermore, chronic clenbuterol administration causes significant repartitioning in the horse, even when administered in therapeutic doses.

The preferential use of dominant over non-dominant limbs produces muscle hypertrophy in the dominant limb. The purpose of this study was to investigate the architectural characteristics of the muscle that are associated with dominant leg use in junior soccer players. Fascicle length, pennation angle and muscle thickness of the medial gastrocnemius (MG) were measured by B-mode ultrasound in 26 junior soccer players [mean (SD) age: 16.5 (0.6) years] and 20 control college students [age: 18.5 (0.5) years]. Lower leg circumference and MG muscle thickness were significantly (P < 0.05) greater in the soccer players than in the controls. The percent difference (dominant minus non-dominant legs) in muscle thickness and fascicle length were significantly (P < 0.01) larger in the soccer players than in the controls, but the percent difference in pennation angle was similar between groups. The difference (dominant leg minus non-dominant leg) in muscle thickness was significantly correlated (r = 0.55; P < 0.05) with the difference in muscle fascicle length in the soccer players, but not in the controls (r = 0.18). In conclusion, the preferential use of one limb over another, as seen in junior soccer players, results in a greater difference in muscle thickness between the dominant and non-dominant legs. This difference in muscle size was associated with longer fascicle lengths of the dominant leg. Thus, it appears possible that fascicle length may be further influenced by physical training in dominant legs.

There have been proposals for a new road around the eastern fringe of Bristol and Kingswood since the 1930s. The completed scheme has long been seen as an essential means of providing improved transportation links to Kingswood and a route for the movement of heavy goods vehicles. The last section, stage II, is finally under construction following a delay of about three years as a result of several legal actions in the High Court by two objectors to the scheme. The paper refers briefly to the whole scheme and then describes the implementation of stage II with particular reference to the statutory procedures, the challenges in the High Court and lessons to be learnt from the management of these processes. The paper also refers to other aspects of the project management including scheme procurement in relation to environmental issues, threats of direct protest action and partnership arrangements in respect of the main works contract. The project acts as an interesting case study to illustrate the challenges faced in implementing traditional road schemes in the context of an increased awareness of the means of objecting to highway construction schemes.

Erythropoietin (EPO) is the primary hormone of erythropoiesis. Administration of recombinant human erythropoietin (rhuEPO) to improve racing performance in the horse represents a new form of blood doping, which has been associated with increased mortality. While immunoassay kits have become plentiful, very few commercial hormone assays are made specifically for equine research. There is a strong degree of sequence homology reported for EPO among species, which has allowed antibodies designed for human EPO research to be used to determine EPO concentration in other species. The objective of the present study was to use Western blot analysis to determine whether the antibody to rhuEPO, provided in a commercial radioimmunoassay (RIA) kit, recognizes horse EPO. Western blot analysis of purified rhuEPO and horse plasma was conducted, using the polyclonal goat-antihuman EPO antibody supplied in the Incstar EPO Trac RIA as the primary antibody. Immunoblot analysis revealed a major band at approximately 52 kDa for both rhuEPO and the horse plasma. Our results demonstrate that a human EPO antibody recognizes equine EPO. These findings show that the Incstar EPO Trac RIA hormone assay system can be used to measure equine EPO.

This paper describes the work of a multidisciplinary, inter-agency team, comprising officers from a recently formed unitary authority and a region of the Environment Agency, to promote the more widespread use of sustainable approaches to tackling drainage problems arising from surface water runoff. Interest in this topical subject is gathering pace nationally and the environmentally positive aspects of this alternative approach are highlighted. The paper provides a brief technical overview of the subject, including the various techniques available. The unitary authority in question is an area subject to considerable development pressure and the paper describes the initiatives taken to pursue changes in planning policy and practices to facilitate the more widespread introduction of the sustainable drainage initiative. The role of elected members at various stages in the process is described. Selected case studies of actual schemes are presented briefly, to help illustrate the range of potential applications.

Older horses have an increased risk of hyperthermia due to impaired cardiovascular function. While many studies have investigated thermoregulation in horses during exercise, none have investigated the effects of ageing.To test the hypothesis that there is a difference in thermoregulation during exercise and plasma volume (PV) in young and old horses.Study 1: 6 young (Y, 7.7 ± 0.5 years) and 5 old (O, 26.0 ± 0.8 years) unfit Standardbred mares (507 ± 11 kg, mean ± s.e.) ran on a treadmill (6% grade, velocity calculated to generate a work rate of 1625 watts) until core temperature reached 40 °C. Core (CT), skin (ST), rectal temperature (RT) and heart rate (HR) were measured every min until 10 min post exertion. Packed cell volume (HCT), lactate (LA) and plasma protein (TP) were measured in blood samples collected before, at 40 °C and every 5 min until 10 min post exercise. Sweat loss was estimated using bodyweight. Study 2: Plasma volume was measured in 26 young (8.2 ± 0.7 years) and 8 old (26.6 ± 0.7 years) Standardbred mares (515 ± 12 kg) using Evans Blue dye. Pre-exercise blood (rBV) and red cell (rRCV) volumes were calculated using PV and HCT. Data analysis utilised repeated measures ANOVA and t tests and data are expressed as mean ± s.e.Old horses reached 40 °C faster (998 ± 113 vs. 1925 ± 259 s; P0.05) with a greater HR at 40 °C (184 ± 6 vs. 140 ± 5 beats/min; P0.05) and greater sweat losses (P0.05). Heart rate did not differ (P0.05) post exercise. Age did not alter (P0.05) CT, ST, RT, LA, HCT or TP. Plasma volume was greater in Y vs. O horses (P0.05, 28.5 ± 1.4 vs. 24.1 ± 1.6 l) as was rBV (41.3 ± 2.0 vs. 35.3 ± 2.3 l) and rRCV (13.3 ± 0.6 vs. 11.1 ± 0.8 l).Ageing compromises the ability to handle the combined demand of exercise and thermoregulation in part due to decreased absolute pre-exercise PV.

Ageing appears to affect immune and neuroendocirne function in horses and response to acute exercise. No studies have examined the combined effects of training and ageing on immune and neuroendocirne function in horses.To ascertain whether training and age would affect the plasma beta-endorphin (BE) and cortisol (C) as well as immune function responses to acute exercise in Standardbred mares.Graded exercise tests (GXT) and simulated race tests (SRT) were performed before and after 12 weeks training at 60 % HRmax. BE and C were measured at rest and at 5, 10, 20, 40, 60 and 120 min post GXT. Leucocyte cell number, CD4+ and CD8+ lymphocyte subsets, and mitogen stimulated lymphoproliferative response (LPR), were measured in jugular blood before and after the SRTs.Cortisol rose by 5 min post GXT in young (Y) and middle-age (MA) mares (P0.05) and remained elevated until 40 and 60 min post GXT, respectively during both pre- and post training GXT. There was no rise in C in old (0) mares after either GXT (P0.05). Pretraining BE rose (P0.05) by 5 min post GXT in all mares. After training, BE was higher in Y and O vs. MA (P0.05) at 5 min post GXT. Post training BE was higher at 5 min post GXT in Y and O vs. pretraining (P0.05). After SRT, lymphocyte number rose in all mares (P0.05); however, lower lymphocyte numbers (P0.05) were seen in MA vs. Y and O vs. MA (P0.05). The O had reduced LPR to Con A and PHA stimulation (P0.05) compared to Y and MA after the SRT after both pre- and post training SRT. LPR to PWM was lower (P0.05) in O vs. Y and MA after the pretraining SRT. Training caused an increase in resting LPR to PWM in MA only (P0.05).Both age and training altered the plasma beta-endorphin and cortisol responses as well as and immune responses to acute exercise.This study provides important information on the effects of ageing and training that will aid in the management and care of an increasing number of active older horses.

Plasma concentrations of adiponectin and leptin were measured in 23 mature Standardbred mares (age: 10+/-3 years) and 12 weanling fillies (10 Quarter Horse/Belgian crossbreds and two Quarter Horses; aged: 4+/-3 months) to test the hypothesis that adipocytokines are proportional to adiposity in horses. Rump fat thickness was measured using B-mode ultrasound and percent body fat (% fat) calculated using a published formula for the estimation of fatness in horses. Plasma adiponectin and leptin were determined using radioimmunoassay. In the absence of purified equine adiponectin or leptin, results were expressed as human equivalents (HE) of immunoreactive (ir) adipocytokines. Plasma ir-leptin HE concentration was positively correlated (r=0.543; P

Effects of longitudinal exercise training and acute intensive exercise (simulated race test) on immune function have not been reported in horses. Clenbuterol, a beta2-adrenergic agonist, is used to manage inflammatory airway disease in horses. This study investigated the interaction of 8 wk of exercise training with or without 12 wk of clenbuterol administration in horses. Twenty-three untrained standardbred mares (10 +/- 3 yr, Mean +/- SE) were used and divided into four experimental groups. Horses given clenbuterol plus exercise (CLENEX; n = 6) and clenbuterol alone (CLEN; n = 6) received 2.4 microg/kg BW of clenbuterol twice daily (in an average volume of 20 mL) on a schedule of 5 d on and 2 d off for 12 wk. The CLENEX group was also aerobically trained 3 d/wk. Mares given exercise alone (EX; n = 5) were aerobically trained for 3 d/wk, and the control group (CON; n = 6) remained sedentary. Both EX and CON horses were administered similar volumes (approximately 20 mL) of molasses twice daily. A simulated race test (SRT) resulted in an elevation in lymphocyte number postexercise (P < 0.05). There was no significant difference after acute exercise in either monocyte or granulocyte number. Acute exercise resulted in a decrease (P < 0.05) in the percentage of CD4+ and an increase (P < 0.05) in the percentage of CD8+ cells. The SRT resulted in a decreased lymphoproliferative response to pokeweed mitogen (P < 0.05). A SRT had no effect on antibody production in response to equine influenza vaccine. The EX group demonstrated greater cortisol concentrations at rest and at all other time points postexercise after completing the training regimen compared with CLENEX horses (P < 0.05). Preexercise (SRT) peripheral blood monocyte number was lower in CLENEX horses than in other treatment groups (P < 0.05). Clenbuterol and exercise training did not significantly affect post-SRT changes in leukocyte numbers. Exercise training resulted in a decrease (P < 0.05) in the percentage of CD8+ cells post-SRT compared with other groups, but the percentage of CD4+ cells was not altered by either clenbuterol or exercise conditioning. Lymphocyte proliferative response was not affected by clenbuterol or exercise treatment. Horses demonstrated responses to bouts of acute exercise as noted with other species, namely humans and rodents.

Locomotion requires skeletal muscle to sustain and generate force. A muscle's force potential is proportional to its weight. Since the larger the muscle the larger its potential power output, a better understanding of the proportion of skeletal muscle a horse possesses may lead to a better understanding of horse performance. Several techniques exist to assess body composition, which include dual energy X-ray absorption, underwater (hydrostatic) weighing, derivation from total body water, bio-electric impedance, air displacement, body condition scoring, cadaver dissection and ultrasound. The relevance of each method to the equine industry will be discussed as will the practical information that the existing horse body composition studies have provided. Attention will be given to the data regarding the implications of body composition on the performance horse. The limited number of studies discussing different varieties of muscle architectures and the functional importance of these muscles will also be addressed. These body composition data may provide a better understanding of important issues in horse care that can lead to more optimal horse care techniques and a healthier and safer environment for horses.

The purpose of this study was to test the hypotheses that ageing would result in a decline in maximal heart rate (HRmax) and maximal aerobic capacity (VO2max) and, secondarily, that those effects would be reversible with training. Eighteen, healthy, unfit Standardbred mares representing 3 age groups: young (Y = mean +/- s.e. 6.8 +/- 0.4 years, n = 6); middle-aged (MA = 15.2 +/- 0.4 years, n = 6); and old (O = 27.0 +/- 0.2 years, n = 6) were used. HRmax, VO2max and oxygen pulse at VO2max (OPmax) and the velocities producing HRmax (VHRmax) and VO2max (VVO2max) were measured during pretraining and post-training incremental exercise tests (GXT). During training, mares exercised 3 days/week (Weeks 1-8) and 4 days/week (Weeks 9-12) at a submaximal intensity (approximately 60% HRmax) for approximately 30 min/day. There were no differences (P0.05) between Y and MA, before (218 +/- 2 vs. 213 +/- 3 beats/min; 116 +/- 3 vs. 109 +/- 3 ml/kg bwt/min; 0.55 +/- 0.01 vs. 0.52 +/- 0.02 ml/kg/beat; 9.0 +/- 0.3 vs. 9.3 +/- 0.2 ms; 8.8 +/- 0.2 vs. 8.8 +/- 0.2 m/s) or after training (224 +/- 2 vs. 218 +/- 2 beats/min; 131 +/- 3 vs. 120 +/- 2 ml/kg bwt/min; 0.58 +/- 0.01 vs. 0.55 +/- 0.01 ml/kg/beat; 10.5 +/- 0.2 vs. 9.5 +/- 0.1 ms; 10.6 +/- 0.2 vs. 9.5 +/- 0.1 m/s) for HRmax, VO2max, OPmax, VHRmax or VVO2max, respectively. Old horses had lower HRmax, VO2max and OPmax and reached them at lower velocities compared to Y and MA (P0.05), both before (193 +/- 3 beats/min; 83.2 +/- 2.0 ml/kg bwt/min; 0.43 +/- 0.01 ml/kg/beat; 7.8 +/- 0.1 m/s; 7.2 +/- 0.1 m/s) and after training (198 +/- 2 beats/min; 95 +/- 2 ml/kg bwt/min; 0.48 +/- 0.01 ml/kg/beat; 8.2 +/- 0.2 m/s; 8.0 +/-0.2 m/s). Training did not alter HRmax in any age group (P0.05) but did cause increases in VO2max, OPmax and VVO2max for all groups (P0.05). Interestingly, training increased VHRmax only in Y (P0.05). These data demonstrate that there is a reduction in HRmax, VO2max, OPmax, VHRmax and VVO2max in old horses, and that training can partially reverse some effects of ageing.

This study examined whether body composition was predictive of competitive success in elite standardbreds (STB). Rump fat and muscle thickness (MTH) (vastus lateralis/intermedius [VL], extensor carpi radialis [ECR]) were measured in vivo in male n=6; female n=8 by B-mode ultrasound. Percentage body fat (%fat) was calculated from rump fat. There were no gender differences for age, body mass (males 432+/-11 kg; females 443+/-13 kg), fat-free mass (FFM) (males 400+/-12 kg; females 400+/-11 kg), ECR MTH (males 61+/-2 cm; females 60+/-2 cm) or race time (RT) (males 113+/-3 s; females 114+/-2 s). Males had less (P

Photon management has been shown to be a fruitful way to boost the open circuit voltage and efficiency of high quality solar cells. Metal or low-index dielectric-based back reflectors can be used to confine the reemitted photons and enhance photon recycling. Gaining access to the back of the solar cell for placing these reflectors implies having to remove the substrate, with the associated added complexity to the solar cell manufacturing. In this work, we analyze the effectiveness of a single-layer reflector placed at the back of on-substrate solar cells, and assess the photon recycling improvement as a function of the refractive index of this layer. Al2O3-based reflectors, created by lateral oxidation of an AlAs layer, are identified as a feasible choice for on-substrate solar cells, which can produce a Voc increase of around 65% of the maximum increase attainable with an ideal reflector. The experimental results obtained using prototype GaAs cell structures show a greater than two-fold increase in the external radiative efficiency and a Voc increase of ∼2% (∼18 mV), consistent with theoretical calculations. For GaAs cells with higher internal luminescence, this Voc boost is calculated to be up to 4% relative (36 mV), which directly translates into at least 4% higher relative efficiency.

Skeletal muscle architecture was measured in 28 college sumo wrestlers (Sumo) and 30 control subjects. Pennation angle (PAN) and muscle thickness (MTH) of the triceps long head (TL), vastus lateralis (VL) and gastrocnemius medialis (MG) and lateralis (LG) muscles were measured by B-mode ultrasonography, and fascicle length (FAL) was estimated. Sumo wrestlers had a significantly greater percentage body fat [mean (SD) 33.9 (9.4)%], fat mass [41.7 (18.5) kg], and fat-free mass [76.8 (7.5) kg] than the controls [15.6 (2.5)%, 9.3 (2.4) kg, and 49.9 (6.2) kg, respectively]. MTH was between 18 and 35% greater in sumo wrestlers than in controls. The sumo wrestlers had a significantly greater PAN in the TL, MG and LG muscles than did the controls, but not in the VL. There were significant correlations between PAN and MTH for the sumo wrestlers (r values from 0.33 to 0.57), suggesting that PAN is a function of the relative state of muscle enlargement. FAL was greater (P < 0.01) in the Sumo group for TL (7.26 cm vs 6.13 cm), VL (10.01 cm vs 6.97 cm) and MG (6.41 cm vs 5.53 cm) than in the controls, but not for LG (7.61 cm vs 7.04 cm). Relative FAL correlated significantly with MTH for these muscles in the Sumo group [r values from 0.45 (P < 0.05) to 0.71 (P < 0.01)]. There appear to be architectural differences in the muscle fascicles between sumo wrestlers and controls, with sumo wrestlers having longer fascicles. A greater FAL appears to limit the degree of change in PAN associated with the extreme muscle enlargement seen in sumo wrestlers. This architectural alteration may ultimately improve the expression of the force/cross-sectional area relationship with extreme muscle enlargement.

Erythropoietin (EPO) is the primary hormone of erythropoiesis. Administration of recombinant human erythropoietin (rhuEPO) to improve racing performance in the horse represents a new form of blood doping, which has been associated with increased mortality. While immunoassay kits have become plentiful, very few commercial hormone assays are made specifically for equine research. There is a strong degree of sequence homology reported for EPO among species, which has allowed antibodies designed for human EPO research to be used to determine EPO concentration in other species. The objective of the present study was to use Western blot analysis to determine whether the antibody to rhuEPO, provided in a commercial radioimmunoassay (RIA) kit, recognizes horse EPO. Western blot analysis of purified rhuEPO and horse plasma was conducted, using the polyclonal goat-antihuman EPO antibody supplied in the Incstar EPO Trac RIA as the primary antibody. Immunoblot analysis revealed a major band at approximately 52 kDa for both rhuEPO and the horse plasma. Our results demonstrate that a human EPO antibody recognizes equine EPO. These findings show that the Incstar EPO Trac RIA hormone assay system can be used to measure equine EPO.

The effect of subhypnotic doses of propofol on intrathecal morphine-induced pruritus was studied in a prospective, randomly allocated, double-blind controlled trial. Fifty-eight women undergoing elective lower segment Caesarean section for a singleton fetus received spinal anaesthesia with 2.5 ml hyperbaric 0.5% bupivacaine and 0.2 mg of preservative-free morphine. They then received propofol 1 ml (10 mg) or Intralipid 1 ml (control group) intravenously after delivery. Pruritus was assessed using a five-point verbal rating scale at hourly intervals for 8 h. A second dose of their allocated treatment drug was administered at the first recording of significant pruritus. The pruritus score was reassessed after 5 min and the treatment was repeated if pruritus remained. There were no differences between the groups in the onset of pruritus or its successful treatment. No adverse side-effects were associated with this dose of propofol. There were no differences in the incidence of post-operative nausea and vomiting between the two groups. Subhypnotic propofol is not an effective treatment for intrathecal morphine-induced pruritus in women following Caesarean section.