Acute hypervolemia does not improve arterial oxygenation in maximally exercising thoroughbred horses

Recently, it was reported that acute hypervolemia improves arterial oxygen tension in human athletes known to experience exercise-induced arterial hypoxemia. Since exercise-induced arterial hypoxemia is routinely observed in racehorses and is known to limit performance, we examined whether pre-exercise induction of acute hypervolemia would similarly benefit arterial oxygenation in maximally exercising thoroughbred horses. Two sets of experiments, namely, placebo [intravenous (IV) physiological saline] and acute hypervolemia (IV 7.2% NaCl, causing an 18.2% expansion of plasma volume) studies were carried out in random order on 13 healthy, exercise-trained thoroughbred horses, 7 days apart. An incremental exercise protocol leading to 120 s of galloping at 14 m s^–1 on a 3.5% uphill incline was used. Galloping at this workload elicited maximal heart rate and induced pulmonary hemorrhage in all horses in both treatments. In the placebo study, arterial oxygen tension decreased to 76.1 (2) mmHg (P<0.0001) at 30 s of maximal exertion, but further significant changes did not occur as exercise duration increased to 120 s [arterial oxygen tension 72.4 (2) mmHg]. A significant arterial hypoxemia also developed in galloping horses in the acute hypervolemia study [arterial oxygen tension at 30 and 120 s was 76.7 (1.7) and 71.9 (1.6) mmHg, respectively], but significant differences between treatments could not be demonstrated. In both treatments, a similar desaturation of arterial hemoglobin was also observed at 30 s of maximal exercise, which intensified with increasing exercise duration as hyperthermia, acidosis and hypercapnia intensified. Thus, acute expansion of plasma volume did not benefit arterial oxygenation in maximally exercising thoroughbred horses.     

肩关节注射治疗冻结肩的研究进展

冻结肩是导致肩关节疼痛及活动受限的常见疾病,肩关节注射是治疗冻结肩的最常用方法,包括糖皮质激素注射、液体扩张疗法、玻璃酸钠注射等。近年来肩关节注射治疗的研究较多,且有较多高质量随机对照研究,该文就糖皮质激素注射与其它治疗手段之间以及注射治疗的不同方式之间在疼痛缓解、活动度及功能改善等方面的疗效及安全性比较作一综述。     

Interlaboratory assessment of mitotic index by flow cytometry confirms superior reproducibility relative to microscopic scoring

A flow cytometric procedure for determining mitotic index (MI) as part of the metaphase chromosome aberrations assay, developed and utilized routinely at Pfizer as part of their standard assay design, has been adopted successfully by Covance laboratories. This method, using antibodies against phosphorylated histone tails (H3PS10) and nucleic acid stain, has been evaluated by the two independent test sites and compared to manual scoring. Primary human lymphocytes were treated with cyclophosphamide, mitomycin C, benzo(a)pyrene, and etoposide at concentrations inducing dose‐dependent cytotoxicity. Deming regression analysis indicates that the results generated via flow cytometry (FCM) were more consistent between sites than those generated via microscopy. Further analysis using the Bland–Altman modification of the Tukey mean difference method supports this finding, as the standard deviations (SDs) of differences in MI generated by FCM were less than half of those generated manually. Decreases in scoring variability owing to the objective nature of FCM, and the greater number of cells analyzed, make FCM a superior method for MI determination. In addition, the FCM method has proven to be transferable and easily integrated into standard genetic toxicology laboratory operations. Environ. Mol. Mutagen. 2012. © 2012 Wiley Periodicals, Inc.     

CEACAM-1 Induced CSF3-receptor Downregulation in Bone Marrow Associated With Refractory Neutropenia in Advanced Cirrhosis

Background and Aims: Cirrhosis patients exhibit cyto-penia, and, at times refractory neutropenia to granulocyte colony-stimulating factor (G-CSF), which acts th...     

Regional coronary blood flow and coronary vascular reserve in unanesthetized calves at rest and during pharmacologic stress

The present study was carried out: (a) To determine whether the uniformity of transmural left ventricular (LV) myocardial blood flow (MBF) is due to a gradient of vasoactive tone or to a gradient of vascularity favoring the deeper layers. (b) To examine the changes in right ventricular (RV) MBF and coronary vascular reserve of conscious calves brought about by various kinds of stress. Hemodynamics and MBF (15-μm tracer microspheres) were studied in six awake calves before and during maximal coronary vasodilatation induced by adenosine infusion (4 μM/kg/min). Although heart rate increased by 46% and mean aortic blood pressure decreased by 29% with adenosine infusion, the RV and LV MBF had increased by 710 and 394%, respectively. Thus under basal conditions we found RV coronary vascular reserve to be greater than that in the LV. The endo:epi ratio during maximal coronary vasodilatation did not decrease below 1.00 in both ventricles. This suggested that normally higher LV subendocardial perfusion (i.e., endo:epi > 1.0) of resting awake calves is most likely not due to a out → in diminishing gradient of vasomotor tone. Minimal coronary vascular resistance was identical for both ventricles. MBF was also studied in six additional calves at control, during isoproterenol infusion (0.2 μg/kg/min), pacing, and acute volume overload before and after propranolol pretreatment. The percentage increase in RV MBF per unit weight was higher than that in the LV MBF with each stress. With isoproterenol stress, LV endo:epi had decreased significantly below 1.0 while RV endo:epi was well maintained. Propranolol pretreatment significantly blunted the increase in RV and LV MBF brought about by acute volume overload.     

Bisalbuminemia in chronic kidney disease

Hereditary and acquired bisalbuminemia, in which the serum contains an albumin variant differing from albumin A by single amino-acid substitutions, have been reported in different races or ethnic groups and in association with various pathologic states. The importance of this rare condition in the pathophysiology of established diseases is uncertain. We evaluated a 68-year-old woman with chronic kidney disease who presented with worsened serum creatinine concentration despite lack of dietary or medical changes. Serum protein electrophoresis was performed with an automated rapid electrophoresis system. Bisalbuminemia was noted as an incidental finding on serum protein electrophoresis. The serum creatinine level stabilized with dietary protein restriction and a -blocking agent/diuretic combination for blood pressure control. Although the possibility that some physiologic or pharmacologic substances may not bind to abnormal albumin variants as well as they bind to normal albumin should not be discounted, the finding of bisalbuminemia did not influence the diagnosis, management, course, or prognosis of chronic kidney disease. The role of persistent bisalbuminemia in renal disease is uncertain.