Influence of exercise and emotional stresses on secretion of prolactin and growth hormone in Thoroughbred horses.

The secretion of prolactin and growth hormone in response to exercise and emotional stresses was investigated in Thoroughbreds. Two experiments were performed: one with loading of only exercise stress and one with simultaneous loading of exercise and emotional stresses. Exercise stress was loaded in 4 steps using a treadmill for horses: pre-exercise period (5 min), walking period (6.5 min), galloping period (3 min), and cooling down period (10 min). Emotional stress was loaded by showing a loud video of an audience at a racetrack during the walking period. The results clearly demonstrated that exercise stress rapidly increased the secretion of prolactin and growth hormone and that secretion of them persisted for a specific period after the exercise. In addition, emotional stress promoted prolactin secretion.

Low-density lipoprotein as a biomarker for the mobilization of hematopoietic stem cells in peripheral blood.

The predictor of hematopoietic stem cells (HSCs) mobilized in peripheral blood (PB) remains unknown. We retrospectively examined the relationship between serum cholesterol level and CD34-positive cells mobilized with granulocyte stimulating factor in PB. PB- mobilized CD34-positive cells were significantly higher in patients with high titers of total cholesterol and low-density lipoprotein cholesterol (LDL-C) than in patients with normal levels (average total cholesterol, 122.94 vs. 51.03/µL, p<0.05; average LDL-C 130.07 vs. 53.77, p<0.05). Multivariable analysis showed that LDL-C significantly influenced PB-mobilized CD34-positive cells, suggesting that LDL-C may be an effective biomarker for mobilization of HSCs in PB.

Pure red cell precursor toxicity by linezolid in a pediatric case.

Linezolid (LZD)-induced myelosuppression has been reported in adults; however, LZD-induced pure red cell precursor toxicity rarely occurs. A 2-year-old boy diagnosed with infective endocarditis by Streptococcus mitis received LZD after developing resistance to multiple antibiotics. Although his infective symptoms were improved by LZD, progressive anemia was noticed 2 weeks after LZD therapy. Four weeks after LZD administration, his hemoglobin level was 6.5 g/dL and reticulocytes less than 0.1%. Bone marrow examination revealed markedly decreased erythropoiesis with cytoplasmic vacuolation of erythroblasts. Anemia recovered 19 days after cessation of LZD. Elevated protoporphyrin and a high LZD level in the blood suggested that mitochondrial disturbance by high-dose and long-term treatment with LZD may have been responsible for LZD-induced pure red cell precursor toxicity.