Endurance exercise in the horse--a review. Part II.
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Animals↗
Biomedical subjects
R J Rose
Publications and source records attributed to R J Rose.
Equine exercise physiology--new horizons.
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Animals↗
Effects of sodium bicarbonate on fluid, electrolyte and acid-base balance in racehorses.
Sodium bicarbonate given by nasogastric tube has been used by some trainers as the key ingredient in a 'milkshake'. It has been suggested that such treatment given 3-5 h prior to racing may enhance a horse's racing performance by increasing the blood buffering capacity and enhancing lactate clearance from skeletal muscle, thereby delaying the onset of fatigue. Several experiments were conducted to examine the effects on fluid, electrolyte and acid-base values of 0.5 g kg-1 dose of sodium bicarbonate, were examined. The effects of fasting, the simultaneous administration of glucose (0.5 g kg-1) or the withholding of water were also examined to determine whether they influenced the uptake and elimination of sodium bicarbonate. Six Thoroughbred horses were used, each wearing a urine and faecal collection harness. Prior to sodium bicarbonate administration, venous blood, urine and faecal samples were collected for 24 h to establish control values. After administration of sodium bicarbonate (0.5 g kg-1) in 2 l of water, samples were collected at various times for up to 46 h. There were significant increases in water consumption, from 0.5-2.3 l h-1 at 2 h post-administration. Urine output increased by approximately three fold and did not return to control levels until 18 h post-administration. Urinary sodium concentration increased from 95 +/- 16 mmol l-1 (mean +/- SEM) to peak values of 349 +/- 12 mmol l-1 at 12 h. In the 24 h after sodium bicarbonate administration, approximately 80% of the sodium intake (NaHCO3+feed) was excreted in the urine. There was no significant change in the total urinary potassium and chloride excretion. Faecal water content did not change following sodium bicarbonate administration, but there was an increase in faecal sodium content. The mean increase in venous blood bicarbonate concentration was 7.6 +/- 0.4 mmol l-1 after the 0.5 kg-1 dose. Water deprivation for 6 h after sodium bicarbonate administration, fasting or the co-administration of glucose did not affect the peak blood bicarbonate concentration or the time to peak concentration. However, the withholding of water did result in a faster rate of decrease in blood bicarbonate concentration when water was resupplied.
Acid-Base Equilibrium↗
Distribution of lactate in plasma and erythrocytes during and after exercise in horses.
The distribution of lactate between red blood cells (RBC) and plasma was examined at rest, during exercise and 30 min after exercise in six Standardbred horses. Lactate and water concentrations were measured in blood and plasma samples collected prior to exercise, during the last 15 s of each step of an incremental exercise test and at 5 min intervals during the first 30 min after exercise. The mean ratio of RBC lactate concentration (RBCLa) to plasma lactate concentration (PLa) prior to exercise was 1.02 +/- 0.34. Haemoconcentration during exercise was associated with more rapid accumulation of lactate in plasma than in RBCs. Mean whole blood lactate concentration (BLa) was only 59% of PLa in samples collected during exercise. BLa was highly correlated with PLa during exercise (r = 0.98; P < 0.001), but individual PLa values differed from predicted BLa values by up to 2.1 mmol l-1 when PLa exceeded 8 mmol l-1. At each exercise speed and time after exercise there was a large variation between horses in the ratio of BLa/PLa. During exercise at 11 m s-1 the ratio ranged from 0.46-0.73. The BLa/PLa ratio was significantly correlated with increasing exercise intensity, (r = -0.68, P < 0.001) and with haematocrit, (r = -0.69, P < 0.001). The effects of PLa and haematocrit on the BLa/PLa ratio during exercise and the post-exercise period varied greatly between horses. The ratio of lactate concentrations in water of RBCs and plasma varied greatly during and after exercise (0.61-1.22). The ratio also varied considerably between horses, with coefficients of variation ranging from 14-34%. Lactate concentrations in RBC and plasma water vary greatly between horses during and after exercise. We concluded that lactate is unevenly distributed between red blood cells and plasma in blood samples centrifuged immediately after collection, and the variability depends on haematocrit.
Animals↗
Gastric emptying of oral rehydration solutions at rest and after exercise in horses.
We examined the gastric emptying (GE) of oral rehydration solutions (ORS) at rest and after exercise in four Standardbred horses. In one study isotonic, cold isotonic (5 degrees C), isotonic containing glucose and hypertonic fluid were tested at rest. In another study, isotonic fluid was given following a bout of treadmill exercise at 70 per cent VO2 max until exhaustion or at rest. In both studies, a single dose of 8 litres was given via nasogastric tube. GE and electrolyte concentrations (Na+, K+ and Cl-) of the stomach content were measured at 15 minutes intervals for one hour. In both studies, 90 per cent of the fluid was emptied within 15 minutes of administration. There was no treatment effect on electrolyte concentrations in either study but significant changes did occur over time. The data showed that GE is unlikely to significantly affect rehydration.
Animals↗
An observational study of the frequency and pattern of use of epidural steroid injection in 25,479 patients with spinal and radicular pain.
BACKGROUND AND OBJECTIVES: Frequency of epidural steroid injections (ESI) and characteristics of patients receiving them are unknown or poorly described. Patients believed to respond better to ESI include young or middle-aged individuals, those with recent onset or a radicular pattern of pain, and patients without previous spinal surgery. The aim of this study is to estimate the frequency of ESI, to examine the characteristics of patients who have them recommended, and to determine if clinical practice reflects published data pertaining to indications for ESI. METHODS: Descriptive data from 25,479 selected patients with spinal and radicular pain were reviewed. Patients were grouped according to whether or not ESI was recommended, scheduled, prescribed, or continued. Prevalence of ESI use and patient characteristics were compared using standard statistical tests. RESULTS: Overall, ESI were recommended to 2,022 (7.9%) patients. Patients with lumbar pain had ESI proposed 12.6% of the time. Those with cervical and thoracic symptoms had ESI recommended 3.7% and 1.8% of the time, respectively. Patients in whom ESI was recommended were more likely to have pain radiation (P <.001), dermatomal pain distribution (P <.001), and neurologic signs (P <.001). They also had a greater incidence of comorbidities (P <.001) and were older (P <.001). There was no difference in the frequency of prior surgery (P =.169) nor was there a difference based on gender (P =.548) in patients not recommended to have ESI. Patients with symptom duration between 1 month and 1 year were more likely to have ESI recommended. CONCLUSIONS: ESI are commonly used to treat patients with spinal and radicular pain. There is some consistency between clinical practice and published recommendations for ESI use.
Analgesia, Epidural↗
The intra-articular use of sodium hyaluronate for the treatment of osteo-arthrosis in the horse.
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Animals↗
The diagnosis and treatment of arthritis in horses.
In this paper on the diagnosis and treatment of arthritis in horses, both degenerative arthritis and septic arthritis are considered. Diagnosis should be made on the combination of clinical examination together with the use of diagnostic aids such as radiology, intra-articular local anaesthesia and synovial fluid analysis. Intra-articular therapy appears to be the most effective in the treatment of degenerative arthritis. Excellent responses to therapy have been reported with corticosteroids, sodium hyaluronate, orgotein and synovial fluid transfer, where joints showed an absence of degenerative changes on radiographs. In septic arthritis, systemic treatment with the appropriate antibiotic, following bacterial culture and sensitivity testing, can produce good results if prompt diagnosis is made.
Journal Article↗
Effects of sodium bicarbonate and sodium chloride on the elimination of etorphine in equine urine.
The combination of large doses of sodium bicarbonate and the potent narcotic, etorphine, has reportedly been given to racehorses in attempts to improve their performance and also to "mask" the presence of etorphine in urine samples. The increased urinary output and pH associated with sodium bicarbonate (approximately 500 g) administration may reduce the urinary concentration of etorphine, making it more difficult to detect. Our experiment was designed to examine the effects of this combination. Six Thoroughbred horses were used in a latin-square design with three horse pairs and three treatments consisting of the following: etorphine (20 micrograms), etorphine (20 micrograms) plus sodium bicarbonate (1.0 g/kg), and etorphine (20 micrograms) plus sodium chloride (0.7 g/kg). Sodium chloride was used to distinguish between the urinary alkalinizing effects of sodium bicarbonate and the diuretic effects associated with the large electrolyte load. Venous blood and urine samples were collected prior to and for 24 h post-treatment. Sodium bicarbonate produced a significant metabolic alkalosis and an increase in urine pH. Both sodium bicarbonate and sodium chloride produced a profound diuresis. After sodium bicarbonate and sodium chloride treatments, the urinary concentration of etorphine, measured by radioimmunoassay (RIA), was reduced and in some cases could not be detected. Extraction of the urine samples, prior to RIA analysis, increased the sensitivity of the assay and in most cases gave a positive result. We conclude that the coadministration of etorphine and sodium bicarbonate or sodium chloride can make the detection of etorphine more difficult because of the dilutional effects associated with the administration of a large electrolyte load.
Animals↗
Hostility as a risk factor for mortality and ischemic heart disease in men.
We report the association between hostility and the incidence of ischemic heart disease (IHD) in 3,750 Finnish men aged 40-59. Hostility was assessed from self-ratings on irritability, ease of anger-arousal, and argumentativeness, and four groups were formed from the summed hostility ratings. At baseline, the age-adjusted relative risk (RR) of the prevalence of angina pectoris between the highest and lowest hostility groups was 2.88 (95% confidence limits (CL), range 1.71-4.77). A three-year follow-up yielded 65 deaths and 109 IHD-incident cases. Hostility did not predict IHD among healthy men, but among men with previous IHD and hypertension (N = 104), the age-adjusted RR of IHD between the highest and lowest hostility groups was 12.9 (95% CL, 3.92-42.6). After standardization for smoking, obesity, heavy alcohol use, and snoring, the RR was 14.6 (95% CL, 1.94-110). When the degree of dyspnea at baseline was also standardized, the RR was 21.1 (95% CL, 1.59-282). Our data suggest that extreme hostility is not a consequence of symptom severity; rather, hostility is a strong determinant of coronary attack among hypertensive men with IHD.
Adult↗
Self-reported hostility and suicidal acts, accidents, and accidental deaths: a prospective study of 21,443 adults aged 25 to 59.
The association of self-reported hostility with morbidity and mortality due to external causes, including suicidal acts, was analyzed in 10,586 Finnish men and 10,857 Finnish women aged 24 to 59 years. Hostility was assessed from self-ratings on irritability, ease of anger-arousal, and argumentativeness. Three groups, low (33.6% of subjects), intermediate (50.6%), and extreme (15.9%), were formed from the self-reported hostility scores. A 6-year mortality follow-up yielded 76 violent deaths among men and 11 among women. A 4-year morbidity follow-up found 399 hospitalizations due to external causes among men and 169 among women. Among men, the risk ratio between the highest and lowest hostility groups was 1.51 (95% confidence interval, 1.16-1.96) for all events due to external causes and 3.6 (95% confidence interval, 1.63-7.89) for suicidal behavior, when effects of age, marital status, social status, and self-reported alcohol use were controlled in a multivariate model. No association was observed between traffic-related injuries and hostility. Hostility did not predict accidents or accidental deaths or suicidal behavior among women.
Accidents↗
The intercarpal ligaments of the equine midcarpal joint, Part 1: The anatomy of the palmar and dorsomedial intercarpal ligaments of the midcarpal joint.
OBJECTIVE: To describe in detail the structure of the medial palmar intercarpal ligament (MPICL), the lateral palmar intercarpal ligament (LPICL), and a dorsomedial intercarpal ligament (DMICL) of the equine midcarpal joint. STUDY DESIGN: Dissections of equine midcarpal joints. ANIMALS AND SAMPLE POPULATION: Ten carpal joints from eight thoroughbred horses. METHODS: Detailed dissections of the midcarpal joint were performed, with particular attention paid to the MPICL, the LPICL, and the DMICL. The attachments and dimensions of these structures were recorded, as well as their behavior during joint movement. RESULTS: The DMICL arose from the dorsomedial surface of the radial carpal bone (CR) and coursed palmarodistally to insert on the dorsomedial aspect of the second carpal bone (C2). The LPICL attached proximally predominantly on the distal part of the palmaromedial surface of the ulnar carpal bone (CU). From here the ligament coursed distomedially and slightly palmarly to the proximal palmarolateral surface of the third carpal bone (C3). The structure of the MPICL was complex. It attached proximally to the distolateral surface of the CR and distally to the proximal palmaromedial surface of C3, and the proximal palmarolateral aspect of the C2. It could be divided into four fiber bundles in all carpi. The predominant direction of fibers was dorsoproximal to palmarodistal, whereas the palmaromedial bundle coursed palmaroproximal to dorsodistal. CONCLUSIONS: The orientation of their fibers indicate that the MPICL and DMICL primarily resist dorsomedial displacement of CR, whereas the LPICL resists dorsolateral displacement of the CU and intermediate carpal bone. CLINICAL RELEVANCE: An understanding of the structure of the intercarpal ligaments of the midcarpal joint is important in interpreting their function and the reasons for damage to their structure.
Animals↗
The intercarpal ligaments of the equine midcarpal joint, Part 2: The role of the palmar intercarpal ligaments in the restraint of dorsal displacement of the proximal row of carpal bones.
OBJECTIVE: To determine the relative contributions of the palmar intercarpal ligaments in the midcarpal joint to the restraint of dorsal displacement of the proximal row of carpal bones. STUDY DESIGN: A biomechanical study of cadaver equine carpi. ANIMALS OR SAMPLE POPULATION: Eight equine forelimbs from six thoroughbred horses. METHODS: With joints in full extension, the radius was dorsally displaced while midcarpal joint displacement was measured. The restraining force at a joint displacement of 1.5 mm was determined from the load-displacement curve. A ligament or pair of ligaments was then cut and the testing procedure repeated. Their contribution to restraining force was calculated as the percentage change in restraining force after the ligament was sectioned. Relative cross-sectional areas of the ligaments tested were measured at the level of the midcarpal joint. RESULTS: The collateral ligaments were the major contributors to the restraint of dorsal displacement (P < .001). In all joints, the palmar intercarpal ligaments contributed a greater proportion than the palmar carpal ligament (PCL) (P < .05). The mean percentage (+/-SEM) contributions to the restraint of dorsal displacement were 62.8 +/- 3.4 for the collateral ligaments, 14.5 +/- 1.4 for the PCL, and 22.7 +/- 2.2 for the palmar intercarpal ligaments. Mean cross-sectional area expressed as a percentage (+/-SEM) of the total ligamentous area were 9.0 +/- 0.3 for the palmar intercarpal ligaments, 27.1 +/- 3.0 for the PCL, and 63.8 +/- 2.8 for the collateral ligaments. CONCLUSIONS: Despite the small size of the palmar intercarpal ligaments, they play an important role in the restraint of dorsal displacement of the proximal row of carpal bones. CLINICAL RELEVANCE: Interpretation, as well as prevention and treatment of intercarpal ligament tearing requires an understanding of their function.
Animals↗
The intercarpal ligaments of the equine midcarpal joint, Part 3: Clinical observations in 32 racing horses with midcarpal joint disease.
OBJECTIVE: To characterize the clinical features of intercarpal ligament pathology and to determine the relationship among palmar intercarpal ligament tearing, dorsomedial intercarpal ligament (DMICL) hypertrophy, and other intraarticular lesions. STUDY DESIGN: Prospective clinical observations. ANIMALS OR SAMPLE POPULATION: Twenty-eight thoroughbred and four standardbred race horses. METHODS: Clinical, radiographic, and arthroscopic examination of 53 midcarpal joints of 32 horses. RESULTS: Palmar intercarpal ligament tearing was observed in 30 joints of 22 horses. Some tearing of the medial palmar intercarpal ligament (MPICL) was present in 27 joints of 20 horses, and tearing of the lateral palmar intercarpal ligament in 9 joints of 7 horses. There was no correlation between the severity of clinical signs recorded and the degree of MPICL tearing. Joints with grade 2-4 MPICL tearing had significantly less cartilage and bone damage than joints with grade 1 or no ligament damage (P < .05). There was a significant inverse relationship between the number and size of intra-articular fractures, as assessed radiographically, and ligament damage (R = -.31). The DMICL was identified in all joints, and in 18 joints the ligament was enlarged. There was a significant correlation between MPICL damage and hypertrophy of the DMICL (R = .35). There was no correlation between DMICL hypertrophy and articular cartilage damage or subchondral bone damage. CONCLUSIONS: Severe subchondral bone and MPICL damage rarely occur in the same joint and DMICL hypertrophy may be associated with, rather than a cause of, joint disease. CLINICAL RELEVANCE: There are no clinical or radiographic findings that will differentiate intercarpal ligament injury from other carpal injuries. Diagnosis is only possible by arthroscopic examination of the midcarpal joint.
Animals↗
A comparison of simultaneously collected arterial, mixed venous, jugular venous and cephalic venous blood samples in the assessment of blood-gas and acid-base status in the dog.
Blood samples were collected simultaneously from the pulmonary artery, jugular vein, cephalic vein, and carotid artery in awake dogs. Blood-gas and acid-base values were measured from these blood samples in normal dogs and in dogs after production of metabolic acidosis and metabolic alkalosis. The values obtained from each of the venous sites were compared with those obtained from arterial blood to determine if venous blood from various sites accurately reflected acid-base balance and could therefore be used in the clinical patient. The results of this study demonstrated significant differences between the blood from various venous sites and the arterial site for PCO2 and pH in all acid-base states. Significant differences for standard bicarbonate (SHCO3) were found only when jugular and cephalic venous blood were compared with arterial blood in dogs with a metabolic acidosis. No significant differences were found for BE when blood from the venous sites was compared with arterial blood. The values for pH, HCO3, TCO2, BE, and SHCO3 measured on blood collected at the various venous sites were found to correlate well with those obtained from arterial blood, with a correlation coefficient of 0.99 for HCO3, TCO2, BE, and SHCO3. These correlation coefficients, together with similar values in BE at all collection sites, indicate that, in the dog with normal circulatory status, blood from any venous site will accurately reflect the acid-base status of the patient.
Acetazolamide↗
An approach to the evaluation of genetic influences on factors that regulate arterial blood pressure in man.
To assess the influence of heredity on factors that help regulate the arterial blood pressure in man, we conducted sodium-loading and depletion studies in monozygotic and dizygotic twins, normotensive first-degree relatives of essential hypertensives, and in normotensive control subjects matched for age, sex, and race. Following sodium-loading, we found evidence for the influence of genetic variance on the natriuretic responses, plasma renin activity (PRA), plasma aldosterone concentrations (PA), and plasma and urinary norepinephrine. Relatives of hypertensives differed from controls in that they had higher blood pressures, greater renin values, and relatively sluggish natriuretic responses. Since renin and fractional sodium excretion values were inversely correlated in all subject groups, it is possible that the heritable influences we observed on sodium excretion were mediated by the renin-angiotensin-aldosterone system.
Adolescent↗
Responses to submaximal treadmill exercise and training in the horse: changes in haematology, arterial blood gas and acid base measurements, plasma biochemical values and heart rate.
Four standardbred horses with subcutaneously relocated carotid arteries were given a seven week training programme of treadmill exercise at a gradient of 19 per cent in order to assess if there were any effects of exercise and training on haematology, arterial blood gas and acid base measurements, plasma biochemistry and heart rate. The exercise consisted of one minute walking at 110 metres/minute followed by five minutes trotting at 200 metres/minute, twice daily in the first week. The period of trotting exercise was increased by one minute per week so that by the seventh week the horses were being given 12 minutes trotting twice daily. Before training commenced venous blood samples, for complete blood counts and plasma biochemistry, and arterial samples, for blood gas, acid base and lactate measurements, were taken at rest, after five minutes and 15 minutes of treadmill exercise (200 metres/minute) and 30 minutes and 60 minutes after completing the exercise. Heart rate was measured by telemetric electrocardiogram at similar intervals. This exercise test and blood collection were repeated after one, three, five and seven weeks of training. The only significant changes were a decrease in exercise lactate with training, increases in exercise and recovery total protein. The haematological response to treadmill exercise included an increase in certain red cell parametes and a leucocytosis which was caused by both a neutrophilia and a lymphocytosis. These effects had largely disappeared by 30 minutes after exercise and all values had returned to resting values by one hour after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
Acid-Base Equilibrium↗
Lower extremity compartment syndrome from prolonged lithotomy position not masked by epidural bupivacaine and fentanyl.
BACKGROUND. Compartment syndrome involving the lower extremity is a rare complication of surgical procedures that incorporate the lithotomy position. In patients who are at risk for this complication, the safety of using postoperative epidural anesthesia with local anesthetics has been questioned because of the difficulty in recognizing compartment syndrome with ongoing epidural blockade. RESULTS. The authors describe a case of lower extremity compartment syndrome that developed after a radical cystectomy with the patient in the lithotomy position. Prompt recognition occurred despite the use of epidural anesthesia with bupivacaine and fentanyl.
Aged↗