bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tissue‐specific dysregulation of cortisol metabolism in equine laminitis
Authors: Johnson P. J. , Ganjam V. K. , Slight S. H. , Kreeger J. M. , Messer N. T. 
Published: April 2007

Summary Reasons for performing study: The role of glucocorticoids (GCs) in the pathogenesis of laminitis is incompletely understood. Local tissue activity of GC is regulated by the steroid converting enzyme, 11β‐hydroxysteroid dehydrogenase‐1 (11β‐HSD‐1). Changes in integumentary (skin and hoof lamellar) 11β‐HSD activity occurring during laminitis could affect the extent to which GCs are involved in its development. Hypothesis: That changes in integumentary 11β‐HSD‐1 activity associated with the laminitic condition would lead to elevated local tissue levels of GCs, which could subsequently contribute, through paracrine and autocrine mechanisms, to the further development of laminitis; and that similar changes in 11β‐HSD‐1 activity would be evident in both skin and hoof lamellar tissue. Methods: Activity of 11β‐HSD‐1 was determined in skin and hoof lamellar tissue specimens obtained from normal and laminitic horses using a radiometric assay. Skin samples were obtained from 10 normal horses and from 10 horses before and after induction of acute laminitis following administration of starch via nasogastric tube. Hoof lamellar samples were obtained from 10 normal horses, 10 horses following induction of acute laminitis and 4 chronically‐foundered horses. Bidirectional 11β‐HSD‐1 activity was measured in both skin and lamellar tissues. Results: 11‐ketoreductase activity exceeded 11β‐dehydrogenase activity in both skin and lamellar tissues. Cutaneous activity was higher than lamellar 11β‐HSD‐1 activity in all groups. Both ketoreductase and dehydrogenase activity increased in skin and lamellae following experimental induction of acute laminitis, but the increase in ketoreductase activity was substantially greater than that for dehydrogenase in the lamellae. Induction of acute laminitis was attended by increases of 227 and 220% in cutaneous dehydrogenase and ketoreductase activity, respectively, and 173 and 398% in lamellar dehydrogenase and ketoreductase activity, respectively (P<0.05). Conclusions: The 11‐ketoreductase moiety of 11β‐HSD‐1 plays a role in equine skin and hoof lamellae regarding the regulation of local glucocorticoid activity. Increased 11‐ketoreductase activity will lead to increased local tissue GC activity by virtue of conversion of cortisone to cortisol. Potential relevance: The laminitic condition is attended by integumentary biochemical changes that enhance the local concentration of cortisol, especially in the hoof lamellar interface. Through multiple and diverse actions, increased local GC activity contributes to the pathogenesis and morbidity associated with laminitis. Pharmacological manipulation of 11β‐HSD‐1 deserves further investigation regarding the prevention and treatment of laminitis.
Nutritional and clinicopathological effects of post operative parenteral nutrition following small intestinal resection and anastomosis in the mature horse
Authors: DURHAM A. E. , PHILLIPS T. J. , WALMSLEY J. P. , NEWTON J. R. 
Published: April 2007

SummaryReasons for performing study: There is an absence of data describing the nutritional requirements and nutritional status of horses following surgery for colic; furthermore, the potential effect of parenteral nutrition (PN) on improving nutritional status in such cases is unknown.Hypothesis: Post operative colic cases suffer from a potentially detrimental negative energy balance and the PN formulation developed in this study would lead to clinicopathologically detectable improvements in the subjects' nutritional status.Methods: Several clinicopathological variables, some known to be associated with nutritional status, were compared in 2 groups of horses in the post operative period following colic surgery;Group N(n = 15) were treated with PN andGroup C(n = 15) were starved routinely.Results: Group Nhad significantly lower serum concentrations of triglycerides, total bilirubin, albumin and urea and significantly higher serum concentrations of glucose and insulin compared withGroup Cin the post operative period.Conclusions: The control group of horses demonstrated significant clinicopathological evidence of starvation and the described PN protocol resulted in a demonstrably improved nutritional status in the treated horses.Potential relevance: Further study is required to investigate clinical benefits and possible harmful side effects of post operative parenteral nutrition before the technique can be advocated for widespread use in practice.
Effect of anaesthesia of the palmar digital nerves on proximal interphalangeal joint pain in the horse
Authors: SCHUMACHER J. , LIVESEY L. , De GRAVES F. J. , SCHUMACHER J. , SCHRAMME M. C. , HATHCOCK J. , TAINTOR J. , GOMEZ J. 
Published: April 2007

Summary Reasons for performing study: Anaesthesia of the palmar digital nerves is claimed to attenuate lameness in some horses that are lame because of pain in the proximal interphalangeal (PIP) joint. Objective: To determine the response of horses with pain in the PIP joint to anaesthesia of the palmar digital nerves. Methods: Horses were video recorded trotting before and after induction of pain in the PIP joint and 10 mins after anaesthesia of the palmar digital nerves. The palmar digital nerves were anaesthetised 3 times at different sites, and the video recorded gaits were scored subjectively. Results: The median lameness score of gaits after administration of 2% mepivacaine 1 cm proximal to the cartilages of the foot was not significantly different from the median lameness score before anaesthesia of the palmar digital nerves (P0.05), although that of 1 of 6 horses improved markedly. The median lameness score was significantly (P0.05) improved after mepivacaine was administered 2 and 3 cm proximal to the cartilages of the foot. Conclusions: The PIP joint is unlikely to be anaesthetised when the palmar digital nerves are anaesthetised at the proximal margin of the cartilages of the foot. Potential relevance: Pain within the PIP joint cannot be excluded as a cause of lameness when lameness is attenuated by anaesthesia of the palmar digital nerves at any site proximal to the proximal margin of the cartilages of the foot.
Why are certain premises at increased risk of equine grass sickness? A matched case‐control study
Authors: Mccarthy H. E. , French N. P. , Edwards G. B. , Miller K. , Proudman C. J. 
Published: April 2007

Summary Reasons for performing study: Equine grass sickness (EGS) occurs repeatedly on certain premises over time. Few studies have sought, or identified, the determinants of this phenomenon in order to inform advice on disease prevention strategies. Hypothesis: Premises‐level risk factors are important determinants of whether EGS occurs. Methods: A matched case‐control study was undertaken. Sixty premises giving rise to one or more histologically confirmed case of EGS and 120 time‐matched control premises were sampled. Data were collected on pasture management, soil nutrient content, pasture nutrient content and local weather conditions for 2 weeks prior to the onset of disease. Data were analysed by conditional logistic regression. Results: Multivariable modelling identified an association between EGS and increased soil nitrogen content, pasture disturbance and previous occurrence of EGS on the premises. None of the meteorological variables recorded in this study were significantly associated with EGS occurrence. No relationship between certain management practices (e.g. harrowing, fertilisation, reseeding) and the risk of EGS was detected. Conclusions and potential relevance: This information is useful in understanding the causal pathway of EGS and may be used in the formulation of evidence‐based disease avoidance strategies.;
The influence of repeated arthrocentesis and exercise on matrix metalloproteinase and tumour necrosis factor a activities in normal equine joints
Authors: Van Den Boom R. , Brama P. A. J. , Kiers G. H. , Degroot J. , Barneveld A. , Van Weeren P. R. 
Published: April 2007

SummaryReasons for performing study: Matrix metalloproteinases (MMPs) and tumour necrosis factor α (TNF‐α) may be useful as biomarkers of joint disease or inflammation. However, activity of both MMPs and TNF‐α in synovial fluid (SF) may be influenced by nonpathological factors such as arthrocentesis or exercise.Objective: To investigate the influence of repeated arthrocentesis and exercise on MMP and TNF‐α activities in SF from normal equine joints.Methods: SF was collected from the left metacarpophalangeal, radiocarpal and tarsocrural joints of 16 horses. Eight of these horses were subsequently subjected to an exercise programme on a treadmill and 8 were box‐rested as controls. Arthrocentesis was repeated 14, 14.5, 17 and 24 days after the start of the exercise programme. General MMP and TNF‐α activities were determined in SF.Results: Repeated arthrocentesis caused a gradual increase but the exercise regimen no significant increase in MMP activity. There was a significant increase in TNF‐α activity in SF collected from horses 2 h after cessation of the exercise programme.Conclusions and potential relevance: When using MMPs as biomarkers for joint disease, at least 14 days should elapse after previous arthrocentesis before subsequent SF collection. Moderate exercise does not increase MMP activity in SF from normal joints and it may be possible to ignore this as a source of error in evaluating MMP activity in diseased joints.;
Pharmacokinetics of recombinant hirudin in healthy horses
Authors: Feige K. , Dennler M. , Kästner S. B. R. , Wunderli‐Allenspach H. , Demuth D. , Huber A. 
Published: April 2007

SummaryReasons for performing study: Recombinant (r)‐hirudin is a specific inhibitor of thrombin that is independent of the activity of antithrombin.Objectives: To evaluate pharmacokinetic properties and coagulatory changes of r‐hirudin in healthy horses.Methods: Two clinically healthy horses received a single i.v. bolus of 0.4 mg/kg bwt r‐hirudin and 6 clinically healthy horses received the same dose subcutaneously (subcut.) q. 12 h for 3 days. Coagulation times and r‐hirudin plasma concentration were determined over 720 mins and 3 days after i.v. and subcut. administration, respectively.Results: In all horses, treatment with r‐hirudin was not associated with systemic or local side effects. After i.v. injection, the 2 horses showed an elimination half‐life of 58 and 80 mins, respectively. After subcut. administration, maximum plasma concentration of r‐hirudin occurred at 128 ± 55 mins and declined with a terminal half‐life of 561 ± 364 mins. Maximum response of activated partial thromboplastin time (aPTT) occurred 1.5 h after administration of r‐hirudin. A prolongation of 1.9 ± 0.2 times the pretreatment value was noted.Conclusions: Pharmacokinetics of r‐hirudin in healthy horses were similar to those in man and other animal species.Potential relevance: The results of this study indicate that r‐hirudin can be used in horses, but further studies should be performed in order to prove its effectiveness in diseased horses.;
Clinical significance of ossification of the cartilages of the front feet based on nuclear bone scintigraphy, radiography and lameness examinations in 21 Finnhorses
Authors: Ruohoniemi M. , Mäkelä O. , Eskonen T. 
Published: April 2007

SummaryReasons for performing study: Research on the clinical significance of ossification of the cartilages of the foot has been limited, despite the common nature of the condition and conflicting reports in previous literature.Hypothesis: Some radiographic features in the ossification of the cartilages, such as incomplete fusion lines between separate centres of ossification and the ossified base, are of clinical significance.Methods: The relationships between radiopharmaceutical uptake in bone phase nuclear scintigraphy at the heels (palmar processes of the distal phalanx, including ossification of the cartilages of the foot), radiographic extent and type of ossification of the cartilages and clinical lameness were evaluated retrospectively in 21 Finnhorses (age ≥4 years) in a total of 36 front feet.Results: No significant relationship between height of the ossifications and radiopharmaceutical uptake at the ipsilateral heels existed. Clearly separate centres of ossification were not associated with increased uptake. Moderately increased uptake was suspected to be associated with ossification of the adjacent cartilage in only one foot. Intense uptake was present unilaterally in 4 horses, at one medial and 3 lateral heels. In 2 of these horses, a unilateral palmar digital nerve block relieved the mild lameness; 2 horses had no obvious lameness but had a history of being stiff or having locomotion problems during high speed trot. At 2 of the lateral heels, an incomplete fusion line was present between a large separate centre of ossification and the base, and the third horse had a high sidebone with bony protrusions, suggestive of chronic entheseopathy in a narrow foot. At the medial heel, an oblique radiograph revealed a faint radiolucent line at the base of the ossification. In all cartilages with intense radiopharmaceutical uptake at the heel and/or lameness, the ossified part of the cartilage was wider and more irregular compared to other ossifications of the front feet of the individual.Conclusions: Increased radiopharmaceutical uptake, associated with a different radiographic appearance from that of other ossifications of the front feet, was a conclusive sign of clinical significance. Obscure locomotion problems were more commonly associated with ossification of the cartilages than true lameness.Potential relevance: This information is useful in lameness and prepurchase examinations and is likely also to be applicable to other coldblooded breeds used for athletic purposes.;
Equine laminitis: cryotherapy reduces the severity of the acute lesion
Authors: Van Eps A. W. , Pollitt C. C. 
Published: April 2007

SummaryReasons for performing study: The hypometabolic and vasoconstrictive effects of cryotherapy could prevent the development of laminitis.Objectives: To use distal limb cryotherapy to prevent laminitis induced by alimentary carbohydrate overload.Methods: Laminitis was induced in 6 Standardbred horses that had one front limb continuously cooled in an ice/water mixture. Lameness evaluation, blinded lamellar histological grading and analysis for lamellar matrix metalloproteinase‐2 (MMP‐2) mRNA expression were used to evaluate the severity of laminitis.Results: Cryotherapy was well tolerated and effective in cooling the feet. In each horse no lameness was observed in the treated limbs. Laminitis histology scores in the treated limbs were significantly less than those of the corresponding untreated forelimbs (P<0.05). Laminitis histology scores in the treated limbs were also significantly less than those of the untreated limbs (fore‐ and hind) as a group (P<0.05). Expression of MMP‐2 mRNA in the iced feet was significantly (P<0.05) less than that detected in the untreated feet.Conclusions: Cryotherapy, when applied to one foot, markedly reduced the severity of acute laminitis in this study. We propose that vasoconstriction (preventing delivery of haematogenous trigger factors) and hypometabolism (reduction in lamellar MMP activity) were the primary therapeutic mechanisms.Potential relevance: Although further research is needed, we suggest cryotherapy as a potentially effective prophylactic strategy in horses at risk of developing acute laminitis.
Equine laminitis: cleavage of laminin 5 associated with basement membrane dysadhesion
Authors: French K. R. , Pollitt C. C. 
Published: April 2007

Summary Reasons for performing study: The key lesion of laminitis is separation at the hoof lamellar dermal‐epidermal interface. For this to happen the structural and adhesion proteins of the basement membrane zone must be altered. Which proteins and how damage to them leads to the lamellar separation of laminitis is unknown. Objectives: To investigate lamellar hemidesmosome and cytoskeleton damage and basement membrane dysadhesion using light microscopy (LM) and immunofluorescence microscopy (IFM). Methods: Cryostat sections of lamellar tissues from 2 control and 6 Standardbred horses with oligofructose induced laminitis were studied using LM and IFM. Plectin, integrin α6 and BP230 antibody was used to label hemidesmosome intracellular plaque proteins and anti‐BP180 and anti‐laminin 5 (L5) was used to label anchoring filament (AF) proteins. Cytoskeleton intermediate filaments were labelled using anti‐cytokeratin 14. The primary antibodies of selected sections were double labelled to show protein co‐localisation. Results: Laminitis caused reduction of transmembrane integrin α6, the AF proteins BP180 and L5, and failure of co‐localisation of BP180 and L5. Proteins of the inner hemidesmosomal plaque, plectin and BP230, were unaffected. Conclusions: Loss of co‐localisation of L5 and BP180 suggests that, during the acute phase of laminitis, L5 is cleaved and therefore, the AFs connecting the epidermis to the dermis, fail. Without a full complement of AFs separation at the lamellar dermo‐epidermal junction occurs. Potential relevance: Suppressing or inhibiting metalloproteinase activity may prevent L5 cleavage and therefore the lamellar dermo‐epidermal separation of laminitis.
Prolonged, continuous distal limb cryotherapy in the horse
Authors: Pollitt C. C. , Van Eps A. W. 
Published: April 2007

Summary Reasons for performing study: The recommended duration of cryotherapy in horses is currently extrapolated from human medicine. Prolonged, continuous cryotherapy (days rather than minutes) may be of therapeutic value if it is safe and well tolerated. Objectives: To evaluate the effect of prolonged, continuous application of ice and water to the equine distal limb. Methods: A slurry of ice and water was applied to the right forelimb of 4 Standardbred horses for 48 h. Hoof temperature, ambient temperature and ice boot temperature were logged continuously and clinical observations recorded every 2 h. Lameness examinations were performed prior to application and 1 week, 6 months and 1 year after removal of the ice boot. Results: Continuous cryotherapy was well tolerated and resulted in marked cooling of the treated foot. No significant variation in clinical parameters was noted, and no lameness or gross pathology noted in the treated limbs at any examination period. Conclusions: The continuous application of ice and water is a safe and effective means of cooling the equine distal limb. The extremely low, constant temperatures achieved may be of benefit in the management of various distal limb conditions. Potential relevance: Providing clinicians and research workers with a potent therapeutic/prophylactic modality for disorders of the equine distal limb.
Biochemical indices of vascular function, glucose metabolism and oxidative stress in horses with equine Cushing's disease
Authors: Keen J. A. , Mclaren M. , Chandler K. J. , Mcgorum B. C. 
Published: April 2007

SummaryReasons for performing study: The mechanisms underlying the increased risk of laminitis in horses with equine Cushing's disease (ECD) are poorly understood.Hypothesis: That abnormalities in glucose homeostasis, similar to those which cause microvascular dysfunction in human diabetics, contribute to development of laminitis in horses with ECD.Methods: Thirty‐one aged horses were divided into 3 groups based on clinical signs and dexamethasone suppression testing (DST).Group 1(n = 12) had clinical ECD as evidenced by hirsutism.Group 2(n = 10) had a positive DST but no hirsutism.Group 3(n = 9) were controls without ECD, with a negative DST and no clinical evidence of ECD. Biochemical indices of glucose metabolism, vascular function and oxidative stress were determined in single morning blood samples.Results: Group 1 had abnormalities in glucose homeostasis, including increased levels of glucose and insulin, compared toGroups 2and3. Groups 1and2had significantly lower plasma thiol (PSH) levels and nonsignificantly lower albumin‐corrected PSH levels than Group 3, consistent with oxidative stress.Conclusions and potential relevance: The observed abnormalities in glucose metabolism and oxidative stress could potentially contribute to development of laminitis in horses with ECD, by similar mechanisms to those that cause microvascular dysfunction in human diabetics. The absence of inter‐group differences in the biochemical indices of vascular function precludes their use as preclinical diagnostic indicators of vascular dysfunction. The study also highlighted limitations in the premortem diagnosis of ECD.
Hyaluronan in horses: physiological production rate, plasma and synovial fluid concentrations in control conditions and following sodium hyaluronate administration
Authors: POPOT M.‐A. , BONNAIRE Y. , GUÉCHOT J. , TOUTAIN P.‐L. 
Published: April 2007

SummaryReasons for performing study: Hyaluronic acid (HA) is an endogenous glycosaminoglycan used in the treatment of joint diseases, but medication control is required by horseracing authorities. Therefore, a medication control policy needs to be established.Objectives: To establish physiological plasma HA concentrations in post race horses, determine the HA endogenous production rate and document the disposition of HA after i.v. and intra‐articular hyaluronic acid administration at recommended therapeutic doses.Methods: Hyaluronan concentrations in plasma were determined using an ELISA specific test; concentrations in synovial fluid were determined using a radiometric binding assay.Results: The overall mean plasma HA concentration in 120 post competition horses was 89 ng/ml. In a group of 6 experimental horses, synovial fluid control concentration was 328 ± 112 μg/ml. After i.v. sodium hyaluronate administration (37.8 mgin toto), the terminal half‐life was very short (43 ± 29 mins) and after a delay of 3 h, the plasma concentration returned to control values. The endogenous HA production rate was 33—164 mgin totoper day, i.e. 1—4 times the recommended i.v. daily dose. Twenty‐four hours after intra‐articular administration, HA concentration was not significantly different from control values (328 ± 112 μg/ml).Conclusions and potential relevance: Due to the rapid disappearance of HA from plasma after i.v. administration and from the joint after intra‐articular administration, long‐term detection needs a more appropriate approach to be developed.