bluuebunny/crossref_metadata_2025 huggingface dataset:
Standardized Exercise Test in Young Endurance Horses
Authors: Robert C , Younes M , Borgetto B , Barrey E
Published: June 2014

Introduction

The objective of this study was to validate a field standardized exercise test (SET) adapted for young endurance horses and to evaluate the effects of age/conditioning level on speed and heart rate values.

Methods

The study involved 31 horses of Arabian origin bred specifically for endurance and aged 4 yo (n = 11), 5 yo (n = 13) or 6 yo (n = 7). The SET consisted of a warm‐up, followed by 15 (4 yo), 30 (5 yo) or 45 (6 yo) minutes of canter at a comfortable steady speed, and finished with 500 meters of fast gallop. Heart rate (HR) was recorded continuously during the SET. The velocities at which HR reached 160 and 200 beats per minute (V160 and V200) were calculated by the linear regression of HR versus speed.

Results

All horses were able to complete the SET. Resting HR was higher in 4 y than in 5 y and 6 y (P<0.05 via Student's t test). HR and velocities during the SET did not vary significantly with age. Mean ± SD values for 4 yo, 5 yo and 6 yo respectively are as follows: Resting HR: 47.5 ± 7.2, 42.3 ± 3.2, 41.3 ± 5.4 bpm; HRcanter: 162.7 ± 14.3, 156.9 ± 17.3, 161.4 ± 10.7 bpm; Vcanter: 22.6 ± 0.9, 22.4 ± 1.2, 23.3 ± 1.6 km/h; HRsprint: 191.3 ± 18.1, 181.7 ± 18.5, 184.1 ± 16.2 bpm; Vsprint: 30.3 ± 3.0, 31.5 ± 6.4, 35.3 ± 6.9 km/h; V160: 25.8 ± 3.5, 24.8 ± 5.0, 27.1 ± 5.8 km/h; V200: 36.8 ± 6.1, 37.4 ± 7.3, 44.3 ± 10.9 km/h; Post‐exercice lactatemia: 7.4 ± 4.5, 13.5 ± 3.6, 5.6 ± 3.4 mmol/l. These values perfectly fit with those described previously for adult endurance horses.

Conclusions

The proposed field SET involved both aerobic and anaerobic metabolism reproducing the progress of an endurance race. Further studies are being conducted to discriminate if possible the effects of age from those of conditioning.

Ethical Animal Research

The study was approved by the Ethics Committee for the Alfort Veterinary School and the University of Paris‐Est; Owner informed consent for participation was obtained. Sources of funding: National Studs (IFCE), The Eperon Funds and the Arabian Horse Association (ACA). Competing interests: none.
Relationship Between Judges′ Comments on Pace and Horses′ Plasma Lactate Concentration in an Official Breed Evaluation Field Test in Icelandic Horses
Authors: Stefánsdóttir G , Kullberg NM , Jansson A
Published: June 2014

Introduction

In an official breed evaluation field test (BEFT) for Icelandic horses, gaits are scored from 5–10 and there is an option for judges to add standardized comments on the gaits. The aim of this study was to test if comments given on pace were related to horses′ plasma lactate concentration (Lac) post BEFT, with the hypothesis that some of the comments would be related to Lac.

Methods

Data was collected from 157 horses (age 4–11 years) at a BEFT in Iceland in 2011. Venous blood samples were obtained after exercise and lactate concentration determined. Judges′ comments were obtained from Worldfengur. The comments that could be given were: ‘good speed’, ‘clear beat’, ‘sure’, ‘big movements’, ‘good suspension’, ‘long strides’ (positive comments); and ‘lack of speed’, ‘unsure’, ‘four‐beat’, ‘short strides’, ‘changing gait’ and ‘jumping out of gait’ (negative comments). Results were separated into two groups (within each comment); horses/pace with the comment and horses/pace without the comment. Data were analysed via ANOVA (Proc GLM, SAS) including sex, age group, comment, average speed and distance (P<0.05).

Results

Lac was higher when pace had comments ‘good speed’ and ‘sure’ than when no comment was given (23.6 ± 1.2 vs. 17.9 ± 0.5, P<0.001; and 20.2 ± 0.9 vs. 18.1 ± 0.6, P<0.05) and was lower when pace had comments ‘lack of speed’ and ‘unsure’ (16.8 ± 1.0 vs. 19.2 ± 0.6; and 16.2 ± 1.0 vs. 19.3 ± 0.5, P<0.05). No other significant effects on Lac were observed.

Conclusions

Horses with pace subjectively judged as fast and ‘sure’ had higher blood lactate concentration indicating that successful pace is more anaerobic than less successful pace.

Ethical Animal Research

The study was approved by the National Animal Research Committee of Iceland. Explicit owner informed consent for participation in this study is not stated. Sources of funding: Developmental Fund of the Icelandic Horse Breeding, the Pálmi Jónsson Natural Conservation Fund and the Stock Protection Fund of the Icelandic Horse breed. Competing interests: none.
A Pilot Study on the Physiological Response to an Official Breed Evaluation Field Test in Icelandic Horses
Authors: Stefánsdóttir GJ , Ragnarsson S , Gunnarsson V , Jansson A
Published: June 2014

Introduction

The aim of this study was to describe the response in heart rate, respiratory rate, rectal temperature, hematocrit and plasma lactate concentration in Icelandic horses performing the riding assessment in an official breed evaluation field test (BEFT) in Iceland (April 2011). It was hypothesized that the riding assessment constituted high intensity exercise.

Methods

Data was collected from 15 of 28 horses shown at the BEFT. Horses were judged for riding abilities (all gaits) on a straight track. Respiratory rate and rectal temperature were recorded and blood samples were taken from the jugular vein before the warm‐up and within 5 min after the riding assessment. Hematocrit was analysed by centrifugation of capillary tubes and plasma lactate concentration using an enzymatic and spectrophotometric method. Velocity, distance and heart rate were recorded (Polar, Kempele, Finland) during the riding assessment. Anova (Proc GLM) was performed in SAS and data is presented as LSMean ± SE (P<0.05).

Results

The distance covered was 2.7 ± 0.1 km, the duration 9:13 ± 0:21 min : sec and the average speed 17.5 ± 0.3 km/h. The peak heart rate was 214 ± 3 bpm. Post‐exercise plasma lactate concentration was 18.6 ± 1.7 mmol/L and there was an increase (P<0.001) in respiratory rate (40 ± 6 to 118 ± 6 breaths/min), rectal temperature (38.1 ± 0.1 to 39.8 ± 0.1°C) and hematocrit (35 ± 2 to 47 ± 2%) following the breed evaluation field test.

Conclusions

The physiological responses indicate that the riding assessment in BEFT is a demanding exercise, requiring some contribution of anaerobic metabolism.

Ethical Animal Research

The study was approved by the National Animal Research Committee of Iceland. Owners and trainers were informed that participation was voluntary. Sources of funding: Developmental Fund of the Icelandic Horse Breeding, the Pálmi Jónsson Natural Conservation Fund and the Stock Protection Fund of the Icelandic Horse breed. Competing interests: none.
Field Investigation of Poor Performance in Thoroughbred Racehorses
Authors: Van Erck Westergren E , Richard E , Audrey A , Art T , Lekeux P
Published: June 2014

Introduction

Racehorses suffering from subclinical diseases are frequently kept in training until they fail expectations during competition. The diagnosis of medical causes of poor performance remains challenging in the field. The aim of this study was to estimate the prevalence of subclinical causes of poor performance in working Thoroughbreds (TB) and to determine which clinical field tests could most appropriately identify them.

Methods

During the course of a training session, a complete clinical screening was performed in 11 healthy controls (C) and 38 poor performing (PP) TB without obvious clinical signs. Exercising ECG and GPS monitoring, blood sample analysis including oxidative stress markers, Doppler echocardiography, respiratory function testing (RFT), post‐exercise endoscopy, tracheal wash (TW) and broncho‐alveolar lavage (BAL) were performed. Statistics included ANOVA and Spearman's test (P<0.05).

Results

Subclinical causes of PP included muscular, respiratory and cardiac disorders. Variables derived from velocity and HR showed significant differences between groups. Lower airway diseases (LAD) were the most frequently diagnosed (33/38), causing significant differences in RFT. Endoscopic observations correlated with TW cytology, but unlike BAL analysis, were insufficient to diagnose all LAD cases. Supra‐ or ventricular premature beats were present only in the PP group but were not associated with echocardiographic abnormalities. Glutathione peroxidase activity was significantly lower in PP.

Conclusions

Velocity, ECG and HR monitoring during a training session can be used as non‐specific predictive indicators of performance, help assess functional consequences of diseases and guide ancillary diagnostic investigations. As LAD is highly prevalent, BAL sampling would be indicated in any case of poor performance.

Ethical Animal Research

The study was approved by the Ethical committee of the University of Liege. Explicit owner informed consent for participation in this study is not stated. Sources of funding: University of Liege, Frank Duncombe Laboratory and the French Haras Nationaux. Competing interests: none.
Post‐Race Plasma Angiotensin Converting Enzyme in Thoroughbred Horses with or without Furosemide
Authors: De Mello Costa M , Ivanow A , MGB Silva A , Ronchi F , Casarini D
Published: June 2014

Introduction

Exercise‐Induced Pulmonary Haemorrhage (EIPH) results from hypertensive episodes associated with intense exercise and can negatively impact athletic performance. Angiotensin converting enzyme (ACE) secretion from pulmonary endothelium is increased during pulmonary disease. This study investigated the effects of furosemide administration on ACE activity, and hypothesised a positive association between EIPH and post‐race plasma ACE.

Methods

Blood samples from 73 horses were collected after racing. ACE activity was measured using a fluorometric method. Respiratory endoscopy determined occurrence and grade of EIPH. Comparison of horses treated or not with furosemide before racing and the occurrence of EIPH were conducted by independent sample t‐tests. In addition, regression analysis was used to investigate the association between ACE activity and EIPH grade for all horses. Other variables analysed included time to endoscopy and haematocrit.

Results

Mean ACE activity in horses not treated with furosemide (n = 47; 91.7 ± 15.9) was significantly higher (P = 0.002) than in treated horses (n = 26; 79.6 ± 13.9). When EIPH positive horses were analysed separately, those treated with furosemide (n = 20; ACE 78.2 ± 11.9) had significantly lower ACE (P = 0.009) than non‐treated horses (n = 17; ACE 90.9 ± 15.9). Regression analysis indicated a polynomial relationship between mean ACE activity and EIPH grade (0, 1, 2 or 3 + 4 + 5; adjusted r2 = 0.99; P<0.001). No other comparisons were statistically significant.

Conclusions

Results indicated associations between ACE activity, EIPH grade and furosemide administration and investigation of the potential use of ACE as a biomarker for EIPH severity in controlled studies are warranted.

Ethical Animal Research

This research was conducted with approval from The Animal Ethics Committee at WINTEC, and informed owner consent was obtained for horses included in this study. Sources of funding: partially funded by a Research Grant from WINTEC. Competing interests: none.
Effect of Head and Neck Position on Upper Airway Function in Standardbred Racehorses
Authors: Johnson K , Noschka E , Allen K , Tilbrook A , Ryan T , Franklin S
Published: June 2014

Introduction

Poll flexion may play an important role in the development of dynamic upper respiratory tract (URT) collapse. However, limited investigations have been performed in Standardbred racehorses.

Methods

Eight Standardbreds were examined during training, once flexed and once in extension, using a randomised crossover design. Head position was maintained using modified check‐reins and head‐neck angle was recorded. On each occasion horses performed 2 rounds of exercise of 2400 m at ∼35 km/h. Speed and heart rate (HR) were measured and blood obtained before and after exercise. URT endoscopy was performed during the second round. Videos were blinded and URT function assessed. HR, plasma lactate (Lac) and speed were compared for different head positions using paired t‐tests. Cortisol was analysed using repeated‐measures ANOVA and URT function using Fisher's exact tests and paired t‐tests (P<0.05).

Results

Data were excluded for one horse where head‐neck angle could not be measured. Flexed and extended head‐neck angles differed significantly (mean: 85.0° vs 97.8°; P = 0.001). All horses showed some form of URT collapse during exercise, although this was only deemed clinically significant in 4 horses with a history of abnormal noise. These horses showed additional abnormalities during flexion. However, mean severity scores did not reach statistical significance (P = 0.08). No significant difference was found for speed, HR or Lac. A significant increase in cortisol was found with exercise (P<0.001). The interaction between time and head position approached significance (P = 0.09) with higher concentrations of cortisol generally occurring in extension rather than flexion.

Conclusions

URT abnormalities may be exacerbated with poll flexion. The use of equipment to modify head position may induce a stress response.

Ethical Animal Research

This study was approved by the University of Adelaide Animal Ethics Committee and owner informed consent obtained. Sources of funding: University of Adelaide honours projects. Competing interests: none.
Evaluation of a Portable System Designed to Measure Ventilatory Parameters and Oxygen Consumption in Unridden Horses
Authors: Katz L , Gough K , Herdan C , McGivney B , Bayly W , Sides R , Hill E
Published: June 2014

Introduction

Measurement of maximal oxygen consumption (VO2max) is the gold standard for assessing aerobic capacity, but in horses requires use of stationary equipment and a high‐speed treadmill. Study objectives were to evaluate a portable system designed to measure VO2 in a field setting and to describe these measurements in a cohort of untrained Thoroughbreds.

Methods

Ventilatory parameters and VO2 were measured in 41 untrained Thoroughbreds (16 colts, 25 fillies, 19.8 ± 1.4 months) using an ergospirometry and oximetry mask with customized software validated for horses galloping on a treadmill with an open‐circuit flow‐through gas collection system. Horses were instrumented with a GPS‐HR monitor, light‐weight mask and data‐capture equipment. Data was collected as horses travelled riderless up a 2% inclined woodchip track. Pre‐ and 5 minute post‐exercise plasma lactate ([La5]), HRpeak, maximal velocity (Vmax) and exercise distance were recorded and analysed by unpaired t‐test and Pearson's correlation (P ≤ 0.05).

Results

All horses tolerated the mask and saddle pad. Exercise distance was 1700.5 ± 33.4 m, Vmax 15.0 ± 1.4 m/s, HRpeak 221.2 ± 9.6 bpm and [La5] 22.7 ± 5.5 mmol/l. Average VO2peak, based on 6 breaths, was 117.7 ± 24.1 ml/kg/min, breathing frequency 125.8 ± 7.1 bpm, inspiratory volume 13.2 ± 1.7 L, expiratory volume 13.4 ± 1.9 L and minute ventilation 1669.3 ± 193.3 L/min. VO2peak was not significantly different between colts (112.2 ± 27.7 ml/kg/min) and fillies (121.4 ± 21.3 ml/kg/min). There were no correlations between VO2peak and other measured parameters. There was a positive linear correlation between VO2peak and HRpeak (P = 0.046, R2 = 0.16).

Conclusions

VO2peak values were similar to published reports for yearling Thoroughbreds. The high exercise intensity and linear relationship between VO2peak and HRpeak provides confidence in the system for field studies of aerobic capacity in untrained, unridden horses.

Ethical Animal Research

Institutional Animal Research Ethics Committee approval was obtained. Sources of funding: Science Foundation Ireland (11‐P1‐ 1166). Competing interests: None.
Arrhythmias in Thoroughbreds During and after Treadmill and Racetrack Exercise
Authors: Navas de Solis C , Green C , Sides R , Seino K , Bayly W
Published: June 2014

Introduction

Healthy and poorly performing horses can display arrhythmias during exercise and immediately afterwards. The relationship of arrhythmias to exercise intensity or type, and their frequency of recurrence, are poorly understood. Clarification of these issues was the objective of this investigation.

Methods

Electrocardiograms were recorded on 9 Thoroughbreds during maximal and submaximal exercise on a racetrack (RA) and treadmill (TM). The frequency of atrial and ventricular arrhythmias for RA and TM were compared using Fisher's Exact Test.

Results

65 workouts (TM = 46, RA = 19; median[range]: 4/horse[2–14]) were performed. Exercising arrhythmias were detected in 4/9 horses (12/65 workouts) and there were post‐exercise arrhythmias in 7/9 horses (20/65 workouts). A single exercising electrocardiogram per horse often did not display all arrhythmias detected over several workouts. 3/9 horses exhibited arrhythmias during the first and second runs while the other 6 had none. 4/9 had 1 post‐exercise arrhythmia. Of 6 horses with >3 runs, 1 displayed arrhythmias each time, 3 never had arrhythmias and 2 sometimes showed arrhythmias during exercise (1/9 and 4/8 workouts, respectively). All 6 intermittently had post‐exercise arrhythmias (median[range]: 50% [9–75%] of workouts). Presence of arrhythmias was positively related to intensity and all occurred at ≥94%HRmax. The frequency of arrhythmias following RA (29%) and TM (12.5%) was not statistically different.

Conclusions

Gallops on TM or RA were equally effective for detecting arrhythmias. The presence/absence of exercising arrhythmias was more repeatable than post‐exercise arrhythmias. Arrhythmias are more likely to be detected at maximal or near‐maximal intensities. A larger population needs to be studied before firm conclusions are drawn.

Ethical Animal Research

The study was approved by an Institutional Animal Care and Use Committee protocol. Sources of funding: Department of VCS, Washington State University. Competing interests: none.
Cost of Transport as a Discriminator of Conditioning in Horses Submitted to Incremental Jumping Tests
Authors: Sotero RC , Soares BOA , Queiroz‐Neto A , Simões HG , Ferraz GC
Published: June 2014

Introduction

Heart rate (HR) and blood lactate (LAC) are biomarkers whose responses to exercise are related to physical fitness. This study evaluated the cost of transport (CT) by assessing the cardiovascular and metabolic efficiency of jumping horses using an incremental jumping test.

Methods

Sixteen Brazilian Sport horses of two fitness levels were used: high‐level jumpers (HL, n = 8) and low‐level jumpers (LL, n = 8). Tests were performed in a sandy jumping arena at a mean velocity of 18 km/h; the tests were distributed into three steps of 4 laps of 74 m, each with 10 obstacles. Each stage consisted of simple obstacles that were 0.40, 0.60 and 0.80 m high. The costs of transport were determined as (HRstep‐HRrest/speed) and (LACstep‐LACrest/speed). During intervals between each stage, blood samples were drawn to determine LAC (mmol/L). Student's t‐test was used for the unpaired samples (P<0.05).

Results

There was no difference in the stage 0.40 m for HR. There were differences in the HL and LL groups, respectively, in the HR related to the effort in the obstacle series 0.60 m [1.7 ± 0.2 bpm/(km/h) and 2.0 ± 0.2 bpm/(km/h) (P = 0.02)]; 0.80 m [1.5 ± 0.2 bpm/(km/h) and 1.7 ± 0.2 bpm/(km/h); (P = 0.04)], and in the LAC for the 0.40 m obstacle [0.05 ± 0.04 mmol/L/(km/h) and 0.10 ± 0.03 mmol/L/(km/h); P = 0.04]; 0.60 m [0.07 ± 0.06 mmol/L/(km/h) and 0.14 ± 0.03 mmol/L/(km/h); (P = 0.006)] and 0.80 m [0.11 ± 0.04 mmol/L/(km/h) and 0.19 ± 0.05 mmol/L/(km/h); P = 0.009].

Conclusions

The CT differentiated horses of high and low level jumping fitness. The HR method (rather than LAC) is particularly useful because it is simple, inexpensive and accessible to trainers and veterinarians.

Ethical Animal Research

All procedures were approved by the institutional animal care and use committee of the university (CEUA, Process: 019281/13). Sources of funding: FAPESP ‐ Fundação de Amparo à Pesquisa do Estado de São Paulo (Process 2011/11080‐0). Competing interests: none.
Evolution of Echocardiographic Dimensions with Age and Training in Young Endurance Horses
Authors: Trachsel DS , Giraudet A , Hervé G , Maso D , Robert C
Published: June 2014

Introduction

Increasing cardiac dimension with endurance training is well known in adult athletes. However, adaptation of the heart to training in growing Arabian type horses is less well documented.

Methods

During the national finals for young endurance horses, standardized echocardiographic examinations were performed before the races by two experienced examiners. In 2011 left ventricle (LV) was assessed in 74 horses aged 4‐years (18), 5‐years (33) and 6‐years (23). In 2012 left atrial (LA) dimensions and the great heart vessels were measured in 122 horses aged 4‐years (32), 5‐years (40) and 6‐years (50). Data were normally distributed; age groups and gender were compared by one‐way ANOVA (Holm‐Sidak test for multiple comparisons, significance P<0.05); relationships between echocardiographic dimensions and body weight (BWT) were assessed by linear regressions.

Results

BWT was highest in 5‐year old horses. LV dimensions increased with age, but for most measurements the difference was significant only for the group of 6‐year old horses. The stroke volume (SV) increased (P = 0.0016) and the heart rate decreased (P = 0.06) with increasing age, leading to a constant cardiac output in all age groups. There was a weak relationship between BWT and SV. Two dimensional LA measurements increased between 4 and 5 years but remained constant between 5 and 6 years. LA area measurements and LA functional indices showed no evolution between the groups. Aortic dimension increased with age but pulmonary artery dimension showed no such increase. No influence of gender on echocardiographic dimensions and function could be found.

Conclusions

Great heart vessels, LA and LV dimensions showed different growth patterns between 4 and 6 years of age.

Ethical Animal Research

Procedures were approved by the Ethics Committee for the Alfort Veterinary School and the University of Paris‐Est under number 12/07/11‐1; owner informed consent was obtained. Sources of funding: National Studs (IFCE), The Eperon Funds and the Arabian Horse Association (ACA). Competing interests: none.
Efficacy of Phenylbutazone Versus Firocoxib in Experimental Lameness in Horses
Authors: Foreman J , Foreman C , Bergstrom B
Published: June 2014

Introduction

There are few refereed blinded controlled documentations of skeletal analgesic efficacy of firocoxib, a selective COX‐2 inhibitor. The objective was to test the hypotheses that intravenous firocoxib and phenylbutazone are comparable in efficacy and that both are more efficacious in alleviating lameness than placebo in an adjustable heart bar shoe model of equine foot pain.

Methods

Eight healthy adult horses (5 Thoroughbreds, 3 Quarter horses, mean age 8.3 ± 0.9 years, age range 4–13 years) underwent weekly intravenous treatments 1 hour after lameness induction. Treatments were isotonic saline placebo (1 ml/45 kg body weight), phenylbutazone (4.4 mg/kg), and firocoxib (label dosage 0.09 mg/kg). Treatments were randomly assigned and administered by co‐investigators who had no input on Heart Rate (HR) and Lameness Score (LS) measurements. Another investigator who was unaware of treatment assignments monitored HR and LS every 20 min for 5 hours after lameness induction and then hourly through 12 hours after treatment. One and two weeks later treatments were shuffled and the experiment was repeated. Repeated measures ANOVA and post hoc Tukey's test were used to identify analgesic effects at a significance level of P<0.05.

Results

HR and LS were not different between saline and firocoxib. Post‐treatment phenylbutazone HR (2.3–3.3, 5, and 10 hours) and LS (2.3–8 hours) were lower than saline (P<0.05). Phenylbutazone HR (10 and 12 hours) and LS (1.67–11 hours) were lower than firocoxib (P<0.05).

Conclusions

It was concluded that firocoxib at this label dosage was not different than placebo and that phenylbutazone was more effective than firocoxib and saline.

Ethical Animal Research

Study approved by the University of Illinois Institutional Animal Care and Use Committee. Sources of funding: Fédération Equestre Internationale. Competing interests: none.
Fatigue in the Superficial and Deep Digital Flexor Muscles During Exercise in Thoroughbred Horses
Authors: Takahashi T , Ohmura H , Mukai K , Matsui A , Aida H
Published: June 2014

Introduction

One of the causes of injury to the superficial digital flexor tendon (SDFT) is assumed to be repeated high intensity loading of the tendon. Earlier fatigue of the deep digital flexor muscle (DDFM) in comparison to the time of fatigue of the superficial digital flexor muscle (SDFM) is also assumed to increase load on the SDFT during long distance running. This study evaluated the fatigue of SDFM and DDFM with maximal exercise.

Methods

Two wire electrodes were inserted into the SDFM and DDFM of 6 Thoroughbred horses (461–557 kg). Electromyogram (EMG) and hoof strain gauge signals were recorded at 2,500 Hz with horses on an inclined treadmill (6%), and filter processing was applied (high‐pass 10 Hz for EMG and low‐pass 200 Hz for strain gauge). Integrated EMG (iEMG), the median frequency (MF) of EMG, and the stride frequency (SF) were compared using paired t‐test during 100–105% heart rate max exercise and trotting before and after maximal exercise.

Results

The SF significantly decreased and iEMG of SDFM tended to decrease during maximal exercise (P = 0.055), while MF of EMG in SDFM and DDFM did not change. The iEMG of SDFM and DDFM significantly decreased and MF of EMG in DDFM tended to decrease at a trot after maximal exercise (P = 0.063).

Conclusions

The DDFM may fatigue earlier than SDFM during long distance running. Further study is needed to evaluate the relationship between the decrease in iEMG of SDFM and DDFM during maximal exercise and the injury to SDFT.

Ethical Animal Research

The study was approved by the Animal Welfare and Ethics Committee of the Japan Racing Association Equine Research Institute. Sources of funding: Japan Racing Association. Competing interests: none.
The Family Assessment Device: An Update
Authors: Mansfield Abigail K. , Keitner Gabor I. , Dealy Jennifer
Published: June 2014

The current study set out to describe family functioning scores of a contemporary community sample, using the Family Assessment Device (FAD), and to compare this to a currently help‐seeking sample. The community sample consisted of 151 families who completed the FAD. The help‐seeking sample consisted of 46 families who completed the FAD at their first family therapy appointment as part of their standard care at an outpatient family therapy clinic at an urban hospital. Findings suggest that FAD means from the contemporary community sample indicate satisfaction with family functioning, while FAD scores from the help‐seeking sample indicate dissatisfaction with family functioning. In addition, the General Functioning scale of the FAD continues to correlate highly with all other FAD scales, except Behavior Control. The cut‐off scores for the FAD indicating satisfaction or dissatisfaction by family members with their family functioning continue to be relevant and the FAD continues to be a useful tool to assess family functioning in both clinical and research contexts.
The alteration of the C‐terminal region of human frataxin distorts its structural dynamics and function
Authors: Faraj Santiago E. , Roman Ernesto A. , Aran Martin , Gallo Mariana , Santos Javier
Published: June 2014

Friedreich's ataxia (FRDA) is linked to a deficiency of frataxin (FXN), a mitochondrial protein involved in iron‐sulfur cluster synthesis. FXN is a small protein with an α/β fold followed by the C‐terminal region (CTR) with a nonperiodic structure that packs against the protein core. In the present study, we explored the impact of the alteration of the CTR on the stability and dynamics of FXN. We analyzed several pathological and rationally designed CTR mutants using complementary spectroscopic and biophysical approaches. The pathological mutation L198R yields a global destabilization of the structure correlating with a significant and highly localized alteration of dynamics, mainly involving residues that are in contact with L198 in wild‐type FXN. Variant FXN 90–195, which is closely related to the FRDA‐associated mutant FXN 81–193, conserves a globular shape with a native‐like structure. However, the truncation of the CTR results in an extreme alteration of global stability and protein dynamics over a vast range of timescales and encompassing regions far from the CTR, as shown by proton–water exchange rates and 15N‐relaxation measurements. Increased sensitivity to proteolysis, observed in vitro for both mutants, suggests a faster degradation rate in vivo, whereas the enhanced tendency to aggregate exhibited by the truncated variant may account for the loss of functional FXN, with both phenomena providing an explanation as to why the alteration of the CTR causes FRDA. These results contribute to understanding how stability and activity are linked to protein motions and they might be useful for the design of target‐specific ligands to control local protein motions for stability enhancement.
Structure‐based studies on the metal binding of two‐metal‐dependent sugar isomerases
Authors: Prabhu Ponnandy , Doan Thi‐Ngoc‐Thanh , Tiwari Manish , Singh Raushan , Kim Sun Chang , Hong Myoung‐Ki , Kang Yun Chan , Kang Lin‐Woo , Lee Jung‐Kul
Published: June 2014

Two‐metal‐dependent sugar isomerases are important in the synthesis of rare sugars. Many of their properties, specifically their metal dependency, have not been sufficiently explored. Here we used X‐ray crystallography, site‐directed mutagenesis, isothermal titration calorimetry and electron paramagnetic resonance spectroscopy to investigate the molecular determinants of the metal‐binding affinity of l‐rhamnose isomerase, a two‐Mn2+‐dependent isomerase from Bacillus halodurans (BHRI). The crystal structure of BHRI confirmed the presence of two metal ion‐binding sites: a structural metal ion‐binding site for substrate binding, and a catalytic metal ion‐binding site that catalyzes a hydride shift. One conserved amino acid, W38, in wild‐type BHRI was identified as a critical residue for structural Mn2+ binding and thus the catalytic efficiency of BHRI. This function of W38 was explored by replacing it with other amino acids. Substitution by Phe, His, Lys, Ile or Ala caused complete loss of catalytic activity. The role of W38 was further examined by analyzing the crystal structure of wild‐type BHRI and two inactive mutants of BHRI (W38F and W38A) in complex with Mn2+. A structural comparison of the mutants and the wild‐type revealed differences in their coordination of Mn2+, including changes in metal–ligand bond length and affinity for Mn2+. The role of W38 was further confirmed in another two‐metal‐dependent enzyme: xylose isomerase from Bacillus licheniformis. These data suggest that W38 stabilizes protein–metal complexes and in turn assists ligand binding during catalysis in two‐metal‐dependent isomerases.

Structured digital abstract

BHRI and BHRI bind by x-ray crystallography (View interaction)
Elucidating the impact of temperature variability and extremes on cereal croplands through remote sensing
Authors: Duncan John M. A. , Dash Jadunandan , Atkinson Peter M.
Published: June 2014

Remote sensing‐derived wheat crop yield‐climate models were developed to highlight the impact of temperature variation during thermo‐sensitive periods (anthesis and grain‐filling; TSP) of wheat crop development. Specific questions addressed are: can the impact of temperature variation occurring during the TSP on wheat crop yield be detected using remote sensing data and what is the impact? Do crop critical temperature thresholds during TSP exist in real world cropping landscapes? These questions are tested in one of the world's major wheat breadbaskets of Punjab and Haryana, north‐west India. Warming average minimum temperatures during the TSP had a greater negative impact on wheat crop yield than warming maximum temperatures. Warming minimum and maximum temperatures during the TSP explain a greater amount of variation in wheat crop yield than average growing season temperature. In complex real world cereal croplands there was a variable yield response to critical temperature threshold exceedance, specifically a more pronounced negative impact on wheat yield with increased warming events above 35 °C. The negative impact of warming increases with a later start‐of‐season suggesting earlier sowing can reduce wheat crop exposure harmful temperatures. However, even earlier sown wheat experienced temperature‐induced yield losses, which, when viewed in the context of projected warming up to 2100 indicates adaptive responses should focus on increasing wheat tolerance to heat. This study shows it is possible to capture the impacts of temperature variation during the TSP on wheat crop yield in real world cropping landscapes using remote sensing data; this has important implications for monitoring the impact of climate change, variation and heat extremes on wheat croplands.
Exogenous connective tissue growth factor preserves the hair‐inductive ability of human dermal papilla cells
Authors: Zhang P. , Ravuri S. K. , Wang J. , Marra K. G. , Kling R. E. , Chai J.
Published: June 2014

Synopsis

Objective

Dermal papilla cells are required for inducing epithelial stem cells during hair morphogenesis and regeneration. Adult human dermal papilla cells lose their hair‐inductive capacity after several in vitro culture passages. Maintaining the hair‐inductive capacity of adult human dermal papilla cells is an obstacle that needs to be overcome to realize tissue‐engineered hair follicles. We hypothesized that connective tissue growth factor (CTGF), a fibrogenic factor known to influence Wnt, BMP and TGF‐β, could influence key signalling pathways in human dermal papilla cells. The purpose of this study was to determine the effect of exogenous connective tissue growth factor on cultured human dermal papilla cells.

Methods

Adult human dermal papilla cells were isolated and cultured in the presence of CTGF (20 or 40 ng mL−1). Human dermal papilla cells positivity was determined using the alkaline phosphatase immunofluorescence. After treatment with CTGF, the proliferation of human dermal papilla cells was assessed. The presence of connective tissue growth factor in human dermal papilla cells was identified by immunofluorescence. The α‐smooth muscle actin protein expression was evaluated by Western blot. Gene expression profile of Wnt, BMP and TGF‐β signalling pathways as well as alkaline phosphatase and versican activity, were determined using real‐time RT‐PCR.

Results

Connective tissue growth factor reduced proliferation rate of cultured human dermal papilla cells in a dose‐dependent manner. Exogenous connective tissue growth factor increased the expression of cytoplasmic connective tissue growth factor, and increased mRNA expression of alkaline phosphatase and β‐catenin, BMP2 and TGF‐β2 in human dermal papilla cells. Versican mRNA level was suppressed and a small increase in α‐smooth muscle actin protein expression was observed.

Conclusion

Exogenous connective tissue growth factor can preserve the innate hair‐inductive ability of adult human dermal papilla cells in vitro cultures, which is controlled through the Wnt, BMP and TGF‐β signalling pathways.
Determination of melanin types and relative concentrations: an observational study using a non‐invasive inverse skin reflectance analysis
Authors: Hani A. F. M. , Baba R. , Shamsuddin N. , Nugroho H.
Published: June 2014

Synopsis

Objective

Melanin is a major skin colour pigment that made up of eumelanin (the dark brown–black colour) and pheomelanin (the light red–yellow colour) pigments. Skin‐whitening products typically contain depigmentation agents that reduce the level of pigmentation by changing the pheomelanin–eumelanin production. Similarly, in skin pigment treatment of skin disorders, the melanin production is managed accordingly. To assess and improve treatment efficacy, it is important to have a measurement tool that is capable of determining the melanin types objectively. So far, the efficacy assessment is subjective. In this study, an inverse skin reflectance pigmentation analysis system that determines eumelanin and pheomelanin content is developed and evaluated in an observational study involving 36 participants with skin photo type IV.

Methods

The reflectance spectra of the left forearms of participants were analysed by the pigmentation analysis system to determine their skin parameters – pheomelanin and eumelanin concentrations, melanosome volume fraction, and epidermal thickness. The determined skin parameters are then inputted into the realistic skin model (RSM) of the Advanced Systems Analyses Program (asap®) to generate the ground truth reflectance spectra for the given skin parameters to validate the system.

Results

The developed pigmentation analysis system is found to be accurate with a spectral error of 0.0163 ± 0.009 between measured reflectance and the reflectance output of the analysis system and RSM. The regression analysis shows a strong linear relationship (R2 = 0.994) indicating good precision. The relative concentrations of pheomelanin (38.23 ± 15.04) and eumelanin (1.68 ± 0.91) analysed by the system gives a ratio of pheomelanin to eumelanin of 0.048 ± 0.029; this value is consistent with previously reported figure of 0.049.

Conclusion

The proposed pigmentation analysis system is able to determine melanin types and their relative concentrations. It has the potential to assess the efficacy of the skin‐whitening and pigmentation treatments objectively in a non‐invasive manner.
Photoperiodic effects on diapause‐associated gene expression trajectories in European Leptinotarsa decemlineata populations
Authors: Lehmann P. , Piiroinen S. , Kankare M. , Lyytinen A. , Paljakka M. , Lindström L.
Published: June 2014

Behavioural and physiological changes during diapause, an important strategy of insects for surviving harsh seasonal conditions, have been intensively studied. The genetic and molecular mechanisms underpinning diapause development are less well known. We took a candidate gene approach to study prediapause gene expression patterns in the Colorado potato beetle (Leptinotarsa decemlineata), an invasive insect that has rapidly spread northwards to high seasonality environments. Newly eclosed beetles originating from southern (Italy) and northern (Russia) Europe were reared under short‐ [12 h light (L):12 h dark (D)] and long‐day (18L:6D) photoperiods for 10 days. This time period includes the sensitive period for the photoperiodic induction and initiation of diapause. Gene expression trajectories of 12 diapause‐related genes (regulatory, metabolic and stress‐resistance) were analysed from 0‐, 5‐ and 10‐day‐old beetles. Gene expression differences increased with age, deviating significantly between populations and photoperiods in 10‐day‐old beetles. The gene expression profiles, particularly those related to energy metabolism and stress‐resistance, indicate that beetles originating from Russia also prepare for diapause under the long‐day photoperiod and show qualitative differences in the diapausing phenotype. Our study shows that population‐dependent differences seen in behavioural and physiological traits connected with diapause in L. decemlineata are also evident in the expression trajectories of diapause‐related genes.
Methuselah‐likegenes affect development, stress resistance, lifespan and reproduction inTribolium castaneum
Authors: Li Chengjun , Zhang Yi , Yun Xiaopei , Wang Yanyun , Sang Ming , Liu Xing , Hu Xingxing , Li Bin
Published: June 2014

Methuselah (Mth) is associated with lifespan, stress resistance and reproduction inDrosophila melanogaster, but Mth is not present in nondrosophiline insects. A number ofmethuselah‐likes(mthls) have been identified in nondrosophiline insects, but it is unknown whether the functions ofmthare shared bymthlsor are divergent from them. Fivemthlshave been identified inTribolium castaneum. Although they have different developmental expression patterns, they all enhance resistance to starvation. Onlymthl1andmthl2enhance resistance to high temperature, whereasmthl4andmthl5negatively regulate oxidative stress inT. castaneum. Unlike in the fly withmthmutation, knockdown ofmthls, exceptmthl3, shortens the lifespan ofT. castaneum. Moreover,mthl1andmthl2are critical forTriboliumdevelopment.mthl1plays important roles in larval and pupal development and adult eclosion, whilemthl2is required for eclosion. Moreover,mthl1andmthl2silencing reduces the fertility ofT. castaneum, andmthl1andmthl4are also essential for embryo development. In conclusion,mthlshave a significant effect on insect development, lifespan, stress resistance and reproduction. These results provide experimental evidence for functional divergence amongmthls/mthand clues for the signal transduction ofMthls.
Violence, Networks, and International Migration from Colombia
Authors: Silva Adriana Carolina , Massey Douglas S.
Published: June 2014

Although Colombia is a major country of emigration, little is known about its citizens' motivations for migration. Social and economic conditions have been studied as determinants of migration, but violence has received less attention. We examine how social networks and violence function to promote emigration from Colombia by linking event‐history data from the Latin American Migration Project to external data on violence and economic conditions. We show that emigration is more likely to be initiated by those with higher education, those with network connections to migrants, and during periods of greater violence and increased police presence. Although violence acts powerfully to determine when people migrate, the geographic distribution of social capital determines where they go. Not surprisingly, migrants go to locations where people in their social networks are currently living or have been earlier.
Exploring the impact of employment policy measures in the context of crisis: The case of Greece
Authors: Dimoulas Constantine
Published: June 2014

The article addresses the economic, social and political dimensions of the Greek work‐welfare nexus in the context of the recent financial crisis. Explaining the main social protection and activation measures before and during the crisis (a reduction in salaries and in the purchasing power of employees partnered with unemployment benefits, contribution subsidies for employers, training and work‐practice vouchers, and fixed‐term quasi‐employment in community services), analysis is offered of the impacts of these. The article concludes that employment measures in Greece are not only residual and inadequate to meet the needs of the unemployed but have not curbed rising unemployment rates.
Networking the unemployed: Can policy interventions facilitate access to employment through informal channels?
Authors: Bonoli Giuliano
Published: June 2014

It is widely known that informal contacts and networks constitute a major advantage when searching for a job. Unemployed people are likely to benefit from such informal contacts, but building and sustaining a network can be particularly difficult when out of employment. Interventions that allow unemployed people to effectively strengthen their networking capability could as a result be promising. Against this background, this article provides some hints in relation to the direction that such interventions could take. First, on the basis of data collected on a sample of 4,600 newly‐unemployed people in the Swiss Canton of Vaud, it looks at the factors that influence jobseekers' decisions to turn to informal contacts for their job search. The article shows that many unemployed people are not making use of their network because they are unaware of the importance of this method. Second, it presents an impact analysis of an innovative intervention designed to raise awareness of the importance of networks which is tested in a randomized controlled trial setting.
Impact of adrenalectomy and dexamethasone treatment on testicular morphology and sperm parameters in rats: insights into the adrenal control of male reproduction
Authors: Silva E. J. R. , Vendramini V. , Restelli A. , Bertolla R. P. , Kempinas W. G. , Avellar M. C. W.
Published: June 2014

Here we investigated the hypothesis that normal levels of glucocorticoids, a class of adrenal steroid hormones, are required for normal testicular and epididymal functions. We examined the effects of the manipulation of glucocorticoid plasma levels by bilateral adrenalectomy (1, 2, 7 and 15 days) alone or in combination with daily treatment with the synthetic glucocorticoid dexamethasone (DEX; 5 μg/kg, i.p., 6 days) on the morphology of the testis and sperm parameters in rats. We showed that adrenalectomy led to a reduction in testicular sperm count and daily sperm production starting 2 days after surgery and a differential decrease in sperm count in the epididymis, according to the region and time post‐adrenalectomy analysed. In parallel, testes from 7‐day adrenalectomized (ADX) rats displayed a higher frequency of damaged seminiferous tubules and the presence of elongated spermatids retained in the basal epithelial compartment in stages IX–XVII, which is indicative of defective spermiation. The alkaline comet assay revealed a late effect of adrenalectomy on epididymal sperm DNA fragmentation, which was increased only 15 days after surgery. DEX treatment prevented the changes in testicular and epididymal sperm count observed in 7‐day ADX rats, but failed to protect the testis from ADX‐induced morphological abnormalities. Thus, our results indicated that glucocorticoids may be involved in events related to the maintenance of spermatogenesis and sperm maturation during adulthood. These findings provide new insights into the importance of adrenal steroids to male fertility.