COLD-INDUCED INCREASES IN ERYTHROCYTE COUNT, PLASMA-CHOLESTEROL AND PLASMA-FIBRINOGEN OF ELDERLY PEOPLE WITHOUT A COMPARABLE RISE IN PROTEIN-C OR FACTOR-X
COLD-INDUCED INCREASES IN ERYTHROCYTE COUNT, PLASMA-CHOLESTEROL AND PLASMA-FIBRINOGEN OF ELDERLY PEOPLE WITHOUT A COMPARABLE RISE IN PROTEIN-C OR FACTOR-X
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DOI：
10.1042/cs0860043
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发表时间：
1994-01-01
期刊：
影响因子：
6
通讯作者：
CAUNCE, M
中科院分区：
文献类型：
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作者：
NEILD, PJ;SYNDERCOMBECOURT, D;CAUNCE, M
1. 6名老年人（66-71岁）和6名年轻人（20-23岁）受试者（每组女性各占一半）在18 ℃的流动空气中冷却2小时，以调查寒冷天气中老年人动脉血栓形成死亡率增加的可能原因。与热中性控制实验相比，皮肤温度（躯干）从35.5 ℃下降到29.5 ℃，核心温度变化不大。2.在寒冷条件下，红细胞计数从4.29 × 10（12）/l上升至4.69 × 10（12）/l，平均红细胞体积无变化，表明血浆体积下降14%或438 ml;水、Na+和K+排泄增加仅导致细胞外水损失179 ml。3.血浆胆固醇和纤维蛋白原浓度在老年受试者中从4.90 mmol/l和2.97 g/l（对照）升高至寒冷时的5.45 mmol/l和3.39 g/l，在年轻受试者中从3.33 mmol/l和1.84 g/l（对照）升高至寒冷时的3.77 mmol/l和2.07 g/l。除年轻受试者的胆固醇外，老年受试者、年轻受试者和整个受试者组的胆固醇均显著增加，并且均接近血浆容量下降的预期值。4.在老年受试者、年轻受试者或整个组中，蛋白C和因子X的血浆水平在寒冷中没有显著增加。5.结果表明，寒冷中血浆液体的损失集中了动脉血栓形成的主要危险因素，而小分子，包括保护性蛋白C，重新分布到组织液中。
1. Six elderly (66-71 years) and six young (20-23 years) subjects (half of each group women) were cooled for 2 h in moving air at 18 degrees C to investigate possible causes of increased mortality from arterial thrombosis among elderly people in cold weather. Compared with thermoneutral control experiments, skin temperature (trunk) fell from 35.5 to 29.5 degrees C, with little change in core temperature. 2. Erythrocyte count rose in the cold from 4.29 to 4.69 x 10(12)/l, without a change in mean corpuscular volume, indicating a 14% or 438 ml decline in plasma volume; increased excretion of water, Na+ and K+ accounted for loss of only 179 ml of extracellular water. 3. Plasma cholesterol and fibrinogen concentrations rose in the elderly subjects from 4.90 mmol/l and 2.97 g/l (control) to 5.45 mmol/l and 3.39 g/l in the cold, and in the young subjects from 3.33 mmol/l and 1.84 g/l (control) to 3.77 mmol/l and 2.07 g/l in the cold. Increases were significant for the elderly subjects, the young subjects and the group as a whole, except for cholesterol in the young subjects, and all were close to those expected from the fall in plasma volume. 4. Plasma levels of Protein C and factor X did not increase significantly in the cold in the elderly subjects, young subjects, or the group as a whole. 5. The results suggest that loss of plasma fluid in the cold concentrates major risk factors for arterial thrombosis, while small molecules, including protective Protein C, redistribute to interstitial fluid.