Comparison of analyses of respiratory gases made with the K4b2 portable and Quark laboratory analysers in horses.

Measurements of minute ventilation (VE) and expired oxygen and carbon dioxide fractions (FeO2 and FeCO2) were measured at rest and during exercise in seven warmblood horses performing two consecutive standardised incremental treadmill exercise tests at submaximal speed, using the portable K4b2 telemetric unit and the laboratory Quark metabolic cart in random order. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were estimated using the Haldane equation. There were no significant differences between the measurements made with the two devices. However, VE was overestimated when the horses were cantering at 10 m/s in comparison with values available in the literature.

Meal size and starch content affect gastric emptying in horses.

REASONS FOR PERFORMING STUDY: Feeding practices have been associated with colic in horses. If meal size and composition have an effect on gastric emptying, this could be one of the mechanisms by which feeding practices are related to the occurrence of colic. OBJECTIVES: To evaluate the effect of meal size and starch content on solid phase gastric emptying. METHODS: Solid phase gastric emptying of 3 different radiolabelled meals, small low-starch (SmLS), small high-starch (SmHS) and large high-starch (LgHS) meals, was measured in 5 horses by scintigraphy using 99mTc-disofenin. Data were compared among meals using nonlinear mixed-effects models and paired t tests. RESULTS: On a percentage basis, SmHS emptied significantly faster than LgHS and SmLS emptied significantly faster than SmHS meals. However, when meals of unequal size were compared by emptying rate in g/min and Kcal/min, LgHS emptied significantly faster than SmHS. CONCLUSIONS: Meal size and composition affect gastric emptying. POTENTIAL RELEVANCE: Further work needs to be performed in order to substantiate the possibility of a relationship between digestive functions and occurrence of colic and gastric ulcers.

Oxygen consumption and gait variables of Arabian endurance horses measured during a field exercise test.

REASONS FOR PERFORMING STUDY: Arabian horses have morphological, muscular and metabolic features designed for endurance races. Their gas exchange and gait variables were therefore measured during a field exercise test. This study presents original respiratory and locomotor data recorded in endurance horses under field conditions. HYPOTHESIS AND OBJECTIVES: Respiratory gas exchange ratio (RER) of Arabian horses at the speed required to win endurance races (18 km/h for 120-160 km) are <1 and running economy (RE) is also low in order to maintain exercise intensity using aerobic metabolism for long intervals. The purpose of this study was to measure oxygen consumption and gait variables in Arabian endurance horses running in the field in order to estimate RER and RE. MATERIALS AND METHODS: Five Arabian horses trained for endurance racing were test ridden at increasing speeds on the field. Their speed was recorded and controlled by the rider using a GPS logger. Each horse was equipped with a portable respiratory gas analyser, which measured breath-by-breath respiratory variables and heart rate. The gait variables were recorded using tri-axial accelerometer data loggers and software for gait analysis. Descriptive statistics and linear regressions were used to analyse the speed related changes in each variable with P < 0.05 taken as significant. RESULTS: At a canter speed corresponding to endurance race winning speed (18 km/h), horses presented a VO(2) = 42 ± 9 ml/min/kg bwt, RER = 0.96 ± 0.10 and RE (= VO(2) /speed) = 134 ± 27 l/km/kg bwt. Linear relationships were observed between speed and VO(2,) HR and gait variables. Significant correlations were observed between VO(2) and gait variables. CONCLUSIONS AND POTENTIAL RELEVANCE: The RER of 0.96 at winning endurance speed indicates that Arabian horses mainly use aerobic metabolism based on lipid oxidation and that RER may also be related to a good coordination between running speed, respiratory and gait parameters.

p53 gene mutations are associated with poor survival in low and low-intermediate risk diffuse large B-cell lymphomas.

BACKGROUND: p53 alterations have been associated with a poor prognosis in aggressive B-cell lymphoma. We investigated the clinical relevance of p53 status in diffuse large B-cell lymphoma (DLBCL), focusing on patients who belong to lower risk groups of the international prognostic index and were uniformly treated. We aimed to determine whether this biological marker could identify among such patients those with a pejorative outcome who could benefit from a distinct therapeutic approach. PATIENTS AND METHODS: We studied 69 patients presenting with no, one (low-risk, n = 40) or two (low-intermediate risk, n = 29) risk factors treated with an anthracyclin-containing induction regimen. p53 exons 5-8 mutations were screened for using denaturing gradient gel electrophoresis and confirmed by direct sequencing. Immunohistochemical detection of p53 protein and of its downstream target p21 were also evaluated in 60 of 69 cases. RESULTS: p53 mutations were detected in 16 of 69 (23%) lymphoma samples. The presence of a p53 gene mutation affected survival (P = 0.01), with a 6-year survival rate estimated to be 44% in mutated patients, compared with 79% in non-mutated ones. Using a stepwise Cox model, p53 mutation constituted the only parameter affecting survival (relative risk = 2.7, P = 0.03). A p53+/p21- immunohistochemical pattern (n = 15), suggestive of a disrupted p53 function, strongly correlated with p53 gene status and was associated with a lower 6-year survival rate when compared with a p53(-) or p53+/p21+ phenotype (47% versus 74%, P = 0.05). CONCLUSIONS: p53 alterations constitute a pejorative biological indicator able to discriminate among clinically defined lower risk patients with DLBCL.