bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hindlimb net joint energies during swing phase as a function of trotting velocity
Authors: CLAYTON H. M. , HOYT D. F. , WICKLER S. J. , COGGER E. A. , LANOVAZ J. L. 
Published: June 2010

SummaryNet joint powers and energies have been described in walking horses during the swing phase of the stride in the fore‐ and hindlimb (Claytonet al.2001). During trotting, swing phase net joint powers have been described in the forelimb but not in the hindlimb. The effects of velocity on power profiles and energy patterns are important in relation to locomotor energetics. The objective of this study was to evaluate velocity‐dependent changes in hindlimb net energy profiles of the swing phase during trotting. Inverse dynamic analysis was used to calculate net joint energies at the hindlimb joints of 6 horses trotting overground at velocities ranging from 2.27‐5.17 m/s. At all velocities, there was net energy generation at the hip and tarsus and net energy absorption at the stifle, fetlock and coffin joints. Velocity‐dependent bursts of energy generation at the hip actively protracted the limb in early swing and initiated retraction in late swing. Synchronous with the bursts of energy generation at the hip were velocity‐dependent bursts of energy absorption across the stifle that acted to control flexion in early swing and extension in late swing. The distal limb was raised and lowered by velocity‐dependent bursts of energy generation that flexed the tarsus in early swing and extended it in late swing. The energy bursts in early swing increased linearly with velocity, whereas the energy bursts in late swing increased as a function of the square or cube of velocity.The results contribute to understanding the mechanisms used to accelerate and decelerate the limbs more rapidly as velocity increases, which is an important consideration in racing and sporting performance.
Heterogeneity of intrapleural pressures during exercise
Authors: JONES J. H. , COX K. S. , TAKAHASHI T. , HIRAGA A. , YARBROUGH T. B. , PASCOE J. R. 
Published: June 2010

SummaryWe determined whether the caudodorsal region of the intrapleural space in exercising horses experiences larger pressure fluctuations than other regions and whether systematic phase‐shifting of peak intrapleural pressures along the length of the thorax suggests the existence of locomotor‐induced intrapleural pressure waves. We utilised percutaneous introducers and solid‐state pressure‐tip transducers implanted along the dorsal aspect of the thorax, mid‐thorax or oesophagus to measure regional intrapleural pressures while 3 horses galloped on a flat treadmill at 13–14 m/s, then recorded pressures from the same catheters when horses exercised intensely (heart rate 170–190 beats/min) while swimming with no ground concussion. Pressure excursions in the caudodorsal region did not vary systematically from other regions during galloping or swimming, nor more than a few torr between different locations. During swimming, peak expiratory pressures were higher than during galloping (68–79 vs. 26–32 torr), and horses breathed explosively at frequencies 5 times slower than while galloping (28 vs. 120/min). During galloping, individual catheter locations registered locomotor concussion; however, this was variable and did not indicate a systematic pressure wave passing through the lung or intrapleural space.
Lactate transport in red blood cells by monocarboxylate transporters
Authors: KOHO N. M. , VÄIHKÖNEN L. K. , PÖSÖ A. R. 
Published: June 2010

SummaryThe lactate transport activity of red blood cells (RBC) varies widely among different species; in equine RBC, the activity of the main lactate carrier, H+‐monocarboxylate co‐transporter (MCT), is distributed bimodally. The influence of lactate transport activity is measurable in vivo; after maximal exercise, the RBC lactate concentration in horses with high (HT) lactate transport activity is higher than in those with low (LT) activity. To study the expression of MCT in HT and LT horses, blood samples were taken from 10 horses at rest and after submaximal exercise. Blood and plasma lactate concentrations, lactate and pyruvate transport activities and the amounts of MCT1, MCT2 and MCT4 were measured. After exercise, RBC lactate concentration was higher in HT (n = 5) than in LT (n = 5) horses. At lactate concentrations of 0.25–30 mmol/l and at a pyruvate concentration of 1 mmol/l, transport activity was higher in HT horses. At a lactate concentration of 0.1 mmol/l, transport was similar. In Western blots, the signals for MCT1 and MCT2 were similar in both groups. The amount of CD147, a chaperone necessary for the activity of MCT1, was lower in LT horses. We suggest that MCT2 transports lactate at low concentrations, while MCT1 is needed at higher concentrations. MCT1 may be less active in LT horses and, therefore, during exercise their capacity to take up lactate is low.Further studies are needed to show whether the differences in lactate influx in RBC affect the function of erythrocytes or the performance capacity of horses.
Does usefulness of potassium supplementation depend on speed?
Authors: HESS T. M. , KRONFELD D. S. , CARTER R. A. , TREIBER K. H. , BYRD B. M. , STANIAR W. B. , SMITH L. T. , GAY L. A. , HARRIS P. A. 
Published: June 2010

SummaryReasons for performing study:Electrolyte mixtures given to counter sweat loss usually contain abundant potassium. However, increases in plasma [K+] occur with exercise and supplementation may further increase plasma levels, potentially increasing the risk of neuromuscular hyperexcitability and development of adverse clinical sequellae. This proposition requires study.Objectives:To compare effects of a K‐rich electrolyte supplement (EM+K) to a K‐free one (EM‐K) on plasma [K+], [Ca++] and acid‐base status during an endurance incremental exercise test on the treadmill.Methods:The test consisted of 3 bouts (simulating loops in an endurance race) of 12 km performed at 6, then 7, then 8 m/sec with 25 min rest stops (S1, S2) between loops on 13 endurance trained Arabian horses (7 EM‐K, 6 EM+K). Electrolytes were supplied orally 60 mins before exercise (Pre) and at each stop. Blood samples were taken before exercise and during exercise, each S and 120 mins of recovery (R). Blood was analysed for pH, PCO2, packed cell volume (PCV), plasma [Na+], [K+], [Cl−], [Ca++], glucose, and lactate [La−]; plasma [H+] and osmolality (osm) were calculated. The dietary cation anion difference (DCAD) was calculated to be ‐27 meq/dose EM‐K and 109 meq in EM+K, respectively.Results:Plasma [H+] decreased during the 6 and 7 m/sec loops, increased during the 8 m/sec loop, and returned to Pre at S1, S2 and R. Plasma [K+] was higher at 8 m/sec and plasma [Ca++] was overall lower in the EM+K group compared to EM‐K. Other findings included higher overall PCV, overall glucose, and [La−] during the 8 m/sec loop (P<0.040) in EM+K compared to EM‐K horses.Conclusions:EM+K supplementation leads to higher plasma [K+] increasing the risk of neuromuscular hyperexcitability during exercise. Acute effects of a lower DCAD in EM‐K may have led to higher plasma [Ca++]. Potassium‐rich electrolytes may have triggered the release of epinephrine, contributing to higher PCV, glucose release and increased lactate production.Potential relevance:Lower plasma [K+] and higher plasma [Ca++] with EM‐K supplementation may help reduce the risk of conditions associated with neuromuscular hyperexcitability occurring especially during higher speeds in endurance races.
Exercise and pharmacological stress echocardiography in healthy horses
Authors: SANDERSEN C. , DETILLEUX J. , ART T. , AMORY H. 
Published: June 2010

SummaryReasons for performing study:Stress echocardiography could be a useful diagnostic test in horses suspected to suffer from exercise‐induced myocardial dysfunction as a cause of exercise intolerance.Objective:To evaluate the effect of treadmill exercise and pharmacological stress test on left ventricular echocardiographic parameters.Methods:Echocardiography was performed in 2 groups of 5 healthy horses, either immediately after a near‐maximal treadmill exercise (Group EXE) or during a pharmacological challenge (Group DOB) consisting of 35 ug/kg atropine, followed by incremental dobutamine infusion rates of 2–6 ug/kg bwt/min for 5 min duration each, which led to a cumulative dobutamine dose of 100 ug/kg. Left ventricular M‐mode parameters were compared at rest and at heart rates of 80, 100, 110, 120 130, and 140 beats/min, within each group.Results:In 2 horses ofGroup EXE, echocardiographic measurements were impossible at 140 and 130 beats/min, as their heart rates dropped too fast in the immediate post exercise period. In the remaining 3 horses image quality was not always satisfactory at heart rates of 130 and 140 beats/min. Systolic left ventricular parameters and fractional shortening measured at 130 and 140 beats/min were significantly different from values obtained at lower heart rates. Horses in Group DOB reached expected heart rates of 80 and 100 beats/min, after the administration of atropine and during a dobutamine infusion rate of 2 ug/kg bwt/min, respectively. Heart rates targets of 110, 120, 130, and 140 beats/min were reached at mean (± s.d.) dobutamine infusion rates of 2.8 ± 0.4, 3.2 ± 0.4, 4.0 ± 0.7, 5 ± 0.7 ug/kg bwt/min, respectively. Systolic left ventricular parameters and fractional shortening at heart rates of 110, 120, 130, and 140 beats/min, were significantly different from values obtained at lower heart rates.Conclusion:The pharmacological stress test induced changes in ventricular dimensions at heart rates of 80 to 140 beats/min. Using this test, high quality images can easily be obtained at heart rates of 140 beats/min. Conversely, in post exercise echocardiography, obtaining good quality images at heart rates of 130 and 140 beats/min is difficult, which limits use of the technique in routine clinical settings.Potential relevance:Further studies should demonstrate the potential of pharmacological stress test as a diagnostic tool in horses suffering from exercise‐induced myocardial dysfunction.
Investigation of blood oxidant/antioxidant markers in healthy competition horses of different breeds
Authors: KIRSCHVINK N. , de MOFFARTS B. , FARNIR F. , PINCEMAIL J. , LEKEUX P. 
Published: June 2010

SummaryReasons for performing study:There is increasing evidence that the equine athlete is exposed to exercise‐induced changes of its oxidant/antioxidant balance and antioxidant supplementation is frequently recommended. However, it is unknown whether there is a specific need for antioxidants according to performance, breed, gender or age.Objectives:To assess whether breed‐, gender‐ and age‐related differences of blood oxidant/antioxidant markers occur in competition horses.Methods:Healthy horses (n = 493) underwent oxidant/antioxidant blood marker determination. Vitamin E, lipophilic antioxidant capacity (ACL), ascorbic acid (AA), glutathione (GSH, GSSG), gluthione peroxidase (GPx), superoxide dismutase (SOD), selenium (Se), copper (Cu), zinc (Zn), lipid peroxides (Pool), oxidised proteins (Protox) were determined, as well as magnesium (Mg), creatine phosphokinase (CPK), lactate dehydrogenase (LDH), packed cell volume (PCV) and haemoglobin (Hb). A mixed linear model assessed the effect of breed, gender and age category. P<0.05 was considered significant.Results:Thoroughbreds showed the highest values of vitamin E, ACL, GPx, PCV and Hb, whilst standardbreds had the highest values of AA and LDH. Jumping horses had the highest Protox values. Females had significantly higher SOD values, whereas most of the other markers were higher in stallions and geldings. Horses age 2–6 years had higher AA, SOD and LDH values than horses age >6 years. Correlation analyses were positive and significant between vitamin E and GPx, VitE and ACL, Se and GPx, Cu and Pool and negative between Pool and vitamin E, Pool and ACL, Protox and GPx, Protox and vitamin E.Conclusions:Blood oxidant/ antioxidant status of horses is influenced by breed, gender and age. The correlation analyses suggest synergistic relations between GPx, vitamin E and Se and an antagonistic relation between Protox‐GPx, Protox‐vitamin E, and Pool‐vitamin E.Potential relevance:The results of this investigation provide definition of the specific need for antioxidants and vitamins in competition horses.
Hormone response to training and competition in athletic horses
Authors: CAYADO P. , MUÑOZ‐ESCASSI B. , DOMÍNGUEZ C. , MANLEY W. , OLABARRI B. , DE LA MUELA M. SÁNCHEZ , CASTEJON F. , MARAÑON G. , VARA E. 
Published: June 2010

SummaryReasons for performing study: It is recognised that the amount of psychological stress that an animal encounters determines the degree of response of the hypothalamic‐pituitary‐adrenal (HPA) axis. In human athletes, the added emotive stress of competition is an important element in the adrenal response. The aim of this study was to examine the effect of show‐jumping as well as dressage on stress levels by comparing horses' stress response at a horse show compared to their familiar home.Methods: Fifty‐one horses involved in competition were used. EDTA blood samples were collected before exercise, upon arrived to the schooling area (control), and k over a jump or dressage course. After sampling, plasma was separated and stored at ‐80°C until determinations of cortisol and ACTH were performed. Fourteen healthy horses not involved in competition were used as control group.Results: Competition induced a significant increase in cortisol and ACTH responses in both, jumping and dressage horses and this effect was more apparent in dressage horses. When horses were most experienced, cortisol and ACTH responses were much lower.Conclusion: This study shows that competition elicits a classic physiological stress response in horses and that different training programmes induce different responses. It suggests that horses involved in competition can provide a good model to study the exercise‐induced stress response.
Muscle characteristics of Dutch Warmblood foals with different genetic background at ages 6 and 12 months
Authors: RIETBROEK N. J. , DINGBOOM E. G. , EVERTS M. E. 
Published: June 2010

SummaryReasons of performing study:To obtain broader insight into the muscle of foals with different genetic background, muscle fibre composition, its post natal development and citrate synthase (CS) activity of thegluteus mediuswere investigated.Hypothesis:Because muscle properties are influenced genetically and related directly to performace ability, muscle characteristics should be affected by selection and correspond with the requirement of ths sports selected for.Methods:The foals were divided intoGroup A, (n = 16), considered an average of the population, andGroup B(n = 36), selected for showjumping. Biopsies were taken deeply from thegluteus mediusmuscle. Fibre type identification was performed immunohistochemically at ages 6 and 12 months. Citrate synthase activity was measured at age 6 months.Results:age 6 months statistically significant differences were found betweenGroups AandBin the proportion oftype I, IIadandIIdfibres. Oxidative fibres (IandIIad) were more abundant inGroup B, while fast‐glycolytic fibres (IId) were more abundant inGroup A.Except forIIa, the fibre type composition at age 12 months had become equal in the 2 groups. The difference in the sum of oxidative fibres (I+IIad+IIad) between GroupsAandBat age 6 months was similar to the difference in CS activity at that age, although the latter was not significant.Conclusions:At age 6 months the 2 groups had different proportions of fibretypes IandIId, but these differences had disappeared at age 12 months.Potential relevance:The muscular response to training at an early age can be interpreted with knowledge of muscle characteristics and its post natal development in foals selected for showjumping.
X trisomy in a sterile mare
Authors: De LORENZI L. , MOLTENI L. , ZANNOTTI M. , GALLI C. , PARMA P. 
Published: June 2010

SummaryThis report concerns the cytogenetic analysis, using both C‐banding and fluorescence in situ hybridisation techniques, of a sterile mare. Results obtained revealed a 2n = 65, XXX condition with no sign of mosaicism. The work supports the suggestion that X trisomy, rare in horse, causes infertility in mares and is not associated to other clearly visible phenotypic features.
Successful Treatment for Carriage of Methicillin-Resistant
Staphylococcus
aureus
and Importance of Follow-Up
Authors: Mollema F. P. N. , Severin J. A. , Nouwen J. L. , Ott A. , Verbrugh H. A. , Vos M. C. 
Published: June 2010

ABSTRACT

With this prospective observational follow-up study of 165 methicillin-resistant
Staphylococcus aureus
(MRSA)-positive individuals (23 health care workers and 142 patients), we determined that our MRSA eradication therapy protocol results in a high success rate (81%). Five or more negative culture sets give a predictive value for MRSA eradication therapy success of >90%. Furthermore, MRSA colonization, at least in the throat, and the presence of wounds just before the start of MRSA eradication therapy are associated with MRSA eradication therapy failure.
Determining UV Inactivation of
Toxoplasma gondii
Oocysts by Using Cell Culture and a Mouse Bioassay
Authors: Ware Michael W. , Augustine Swinburne A. J. , Erisman David O. , See Mary Jean , Wymer Larry , Hayes Samuel L. , Dubey J. P. , Villegas Eric N. 
Published: June 2010

ABSTRACT

The effect of UV exposure on
Toxoplasma gondii
oocysts has not been completely defined for use in water disinfection. This study evaluated UV-irradiated oocysts by three assays: a SCID mouse bioassay, an
in vitro T. gondii
oocyst plaque (TOP) assay, and a quantitative reverse transcriptase real-time PCR (RT-qPCR) assay. The results from the animal bioassay show that 1- and 3-log
10
inactivation is achieved with 4 mJ/cm
2
UV and 10 mJ/cm
2
low-pressure UV, respectively. TOP assay results, but not RT-qPCR results, correlate well with bioassay results. In conclusion, a 3-log
10
inactivation of
T. gondii
oocysts is achieved by 10-mJ/cm
2
low-pressure UV, and the
in vitro
TOP assay is a promising alternative to the mouse bioassay.
Novel Florfenicol and Chloramphenicol Resistance Gene Discovered in Alaskan Soil by Using Functional Metagenomics
Authors: Lang Kevin S. , Anderson Janet M. , Schwarz Stefan , Williamson Lynn , Handelsman Jo , Singer Randall S. 
Published: June 2010

ABSTRACT

Functional metagenomics was used to search for florfenicol resistance genes in libraries of cloned DNA isolated from Alaskan soil. A gene that mediated reduced susceptibility to florfenicol was identified and designated
pexA
. The predicted PexA protein showed a structure similar to that of efflux pumps of the major facilitator superfamily.
A Second Soluble Hox-Type NiFe Enzyme Completes the Hydrogenase Set in
Thiocapsa roseopersicina
BBS
Authors: Maróti Judit , Farkas Attila , Nagy Ildikó K. , Maróti Gergely , Kondorosi Éva , Rákhely Gábor , Kovács Kornél L. 
Published: June 2010

ABSTRACT

Three functional NiFe hydrogenases were previously characterized in
Thiocapsa roseopersicina
BBS: two of them are attached to the periplasmic membrane (HynSL and HupSL), and one is localized in the cytoplasm (HoxEFUYH). The ongoing genome sequencing project revealed the presence of genes coding for another soluble Hox-type hydrogenase enzyme (
hox2FUYH
). Hox2 is a heterotetrameric enzyme; no indication for an additional subunit was found. Detailed comparative
in vivo
and
in vitro
activity and expression analyses of HoxEFUYH (Hox1) and the newly discovered Hox2 enzyme were performed. Functional differences between the two soluble NiFe hydrogenases were disclosed. Hox1 seems to be connected to both sulfur metabolism and dark/photofermentative processes. The bidirectional Hox2 hydrogenase was shown to be metabolically active under specific conditions: it can evolve hydrogen in the presence of glucose at low sodium thiosulfate concentration. However, under nitrogen-fixing conditions, it can oxidize H
2
but less than the other hydrogenases in the cell.
Xer Site-Specific Recombination, an Efficient Tool To Introduce Unmarked Deletions into Mycobacteria
Authors: Cascioferro Alessandro , Boldrin Francesca , Serafini Agnese , Provvedi Roberta , Palù Giorgio , Manganelli Riccardo 
Published: June 2010

ABSTRACT

Genetic manipulation of mycobacteria still represents a serious challenge due to the lack of tools and selection markers. In this report, we describe the development of an intrinsically unstable excisable cassette for introduction of unmarked mutations in both
Mycobacterium smegmatis
and
Mycobacterium tuberculosis
.
Validation of a Nylon-Flocked-Swab Protocol for Efficient Recovery of Bacterial Spores from Smooth and Rough Surfaces
Authors: Probst Alexander , Facius Rainer , Wirth Reinhard , Moissl-Eichinger Christine 
Published: June 2010

ABSTRACT

In order to meet planetary-protection requirements, culturable bacterial spore loads are measured representatively for the total microbial contamination of spacecraft. However, the National Aeronautics and Space Administration's (NASA's) cotton swab protocols for spore load determination have not changed for decades. To determine whether a more efficient alternative was available, a novel swab was evaluated for recovery of different
Bacillus atrophaeus
spore concentrations on stainless steel and other surfaces. Two protocols for the nylon-flocked swab (NFS) were validated and compared to the present NASA standard protocol. The results indicate that the novel swab protocols recover 3- to 4-fold more (45.4% and 49.0% recovery efficiency)
B. atrophaeus
spores than the NASA standard method (13.2%). Moreover, the nylon-flocked-swab protocols were superior in recovery efficiency for spores of seven different
Bacillus
species, including
Bacillus anthracis
Sterne (recovery efficiency, 20%). The recovery efficiencies for
B. atrophaeus
spores from different surfaces showed a variation from 5.9 to 62.0%, depending on the roughness of the surface analyzed. Direct inoculation of the swab resulted in a recovery rate of about 80%, consistent with the results of scanning electron micrographs that allowed detailed comparisons of the two swab types. The results of this investigation will significantly contribute to the cleanliness control of future life detection missions and will provide significant improvement in detection of
B. anthracis
contamination for law enforcement and security efforts.
Requirement of the Type II Secretion System for Utilization of Cellulosic Substrates by
Cellvibrio japonicus
Authors: Gardner Jeffrey G. , Keating David H. 
Published: June 2010

ABSTRACT

Cellulosic biofuels represent a powerful alternative to petroleum but are currently limited by the inefficiencies of the conversion process. While Gram-positive and fungal organisms have been widely explored as sources of cellulases and hemicellulases for biomass degradation, Gram-negative organisms have received less experimental attention. We investigated the ability of
Cellvibrio japonicus
, a recently sequenced Gram-negative cellulolytic bacterium, to degrade bioenergy-related feedstocks. Using a newly developed biomass medium, we showed that
C. japonicus
is able to utilize corn stover and switchgrass as sole sources of carbon and energy for growth. We also developed tools for directed gene disruptions in
C. japonicus
and used this system to construct a mutant in the
gspD
gene, which is predicted to encode a component of the type II secretion system. The
gspD
::pJGG1 mutant displayed a greater-than-2-fold decrease in endoglucanase secretion compared to wild- type
C. japonicus
. In addition, the mutant strain showed a pronounced growth defect in medium with biomass as a carbon source, yielding 100-fold fewer viable cells than the wild type. To test the potential of
C. japonicus
to undergo metabolic engineering, we constructed a strain able to produce small amounts of ethanol from biomass. Collectively, these data suggest that
C. japonicus
is a useful platform for biomass conversion and biofuel production.