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Rapid immobilization after acute spinal cord injury (SCI) leads to increased bone resorption, net calcium efflux from the bone, hypercalciuria, depressed parathormone (PTH) and increased calcitonin release. However, the effects, if any, of long-standing SCI on calcium regulatory system is not well understood. We measured plasma concentrations of 25 hydroxy (OH) vitamin D, 1,25(OH)2 vitamin D (calcitriol), intact PTH molecule, calcitonin, ionized calcium [Ca++] and phosphorus in 40 clinically stable men with long-standing SCI of 3-year to 50-year duration (22 persons with paraplegia and 18 persons with quadriplegia). The results were compared with those obtained in 14 able-bodied control men. Plasma PTH concentration in the SCI group was significantly lower than that found in the able-bodied controls despite virtually identical concentrations of ionized calcium. Likewise, plasma calcitriol concentration in the SCI group was significantly lower than the value found in the able-bodied control group and lower in persons with quadriplegia than in those with paraplegia. In contrast, plasma calcitonin concentration in the quadriplegic group was significantly higher than that in persons with paraplegia and insignificantly higher than that in the control group. No significant difference was noted in serum ionized calcium between the study groups. PTH and calcitriol levels were positively related to one another (r = 0.35, p < .01) and negatively related to the level of injury (r = -0.43, p < .002 and r = -0.54, p < .001, respectively). In conclusion, long-standing SCI is associated with significant depression of calcitriol and PTH concentrations despite normal ionized calcium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial hypertension (HTN) increases the risk of cerebral coronary, and other vascular complications that frequently involve platelet activation and blood coagulation. Several key proteins in the blood coagulation, fibrinolytic and inhibitory systems were studied in 29 men with HTN (aged 45 +/- 3 yr) and 15 normal men of the same age. Plasma levels of high-molecular-weight kininogen and factors XII, IX, VII, X, II, and XIII, as well as von Willebrand factor (vWF), fibrinogen, fibronectin, alpha 2-antiplasmin, tissue-plasminogen activator, D-dimer, platelet factor-4, and protein C were measured by the use of appropriate functional and immunologic assays before and after a cardiopulmonary exercise stress test. The concentrations of vWF, alpha 2-antiplasmin, and D-dimer were significantly (P < 0.02) higher in the HTN group as compared with the control group. The exercise stress test resulted in significant rises in the plasma vWF, alpha 2-antiplasmin, and tissue-plasminogen activator levels in the two groups. The concentrations of vWF and D-dimer were related to diastolic blood pressure (r = 0.44 and 0.40, respectively; P < 0.02). Levels of vWF also were related to left ventricular mass index and left ventricular posterior wall and septal thickness (r = 0.34, 0.43, and 0.34, respectively; P < 0.05). The constellation of these findings suggests a low-grade fibrin formation and degradation, the magnitude of which is related to the diastolic blood pressure. The observed abnormalities can potentially contribute to the cardiovascular complications of untreated HTN.