Plasma D-dimer level is clinically useful for diagnosing patients with suspected deep vein thrombosis (DVT). However, the cut-off value for the D-dimer level remains controversial and undetermined with regard to total hip arthroplasty (THA). The objective of this study was to estimate the efficacy of an age- and D-dimer-based index for diagnosing DVTs in asymptomatic cases before THA. We enrolled 224 patients with no symptoms associated with DVT before THA. All the patients underwent ultrasonography, and the plasma D-dimer level was recorded about 1 month preoperatively. The optimal cut-off value was calculated using multiple logistic regression and receiver operating curve analyses. DVTs were detected in 13 patients (5.8%) using ultrasonography. Multiple logistic regression analysis demonstrated that age (odds ratio [OR]: 1.13; p = 0.007) and D-dimer value (OR: 1.74; p = 0.003) were related to the existence of preoperative DVT. A DVT index (0.12 × age + 0.45 × the D-dimer value) of 8.15 was the most reasonable cut-off value according to the receiver operating curve analysis. This value caused 100% sensitivity and 70.1% specificity, with an area under the curve (AUC) of 0.905 (range, 0.836–0.975). For age and D-dimer value, the AUCs were 0.828 (0.749–0.907) and 0.716 (0.522–0.910), respectively. This study demonstrated that age and D-dimer index can be useful in screening patients for DVTs before THA. This DVT index is also easy to calculate and may be clinically significant.
Ovulation accompanied by tissue damage can cause an increase in the level of tissue factor (TF) in the follicular fluid, triggering the extrinsic coagulation pathway. However, follicular fluid must block fibrin formation and maintain fluidity until the release of the oocyte at ovulation. The combination of sulfated proteoglycan, antithrombin, and TF pathway inhibitor (TFPI) appears to play a critical role in the hypocoagulability of human follicular fluid. When compared with plasma, folicular fluid differs markedly in the levels of a number of important coagulation proteins. Principal among these are 15-fold, 13-fold, and 3.7-fold increases in free TFPI, thrombin-antithrombin complex, and TF, respectively. The excessively prolonged activated partial thromboplastin time (APTT) and prothrombin time (PT) of human ovarian follicular fluid appear to be primarily due to high concentrations of sulfated proteoglycans, which accelerate the inactivation of thrombin and the anti-Xa activity of TFPI. Thus, heparitinase treatment shortened the clotting times of follicular fluid and reduced the inhibition of thrombin by the proteoglycan fraction combined with a fraction containing antithrombin. The remaining prolongation of APTT and PT may be caused by high levels of free TFPI in follicular fluid, which were confirmed by Northern blotting analysis, demonstrating TFPI mRNA expression by granulosa cells.
Plasminogen activator (PA) activity in the rat uterus was measured at fixed intervals post partum in order to determine whether this serine protease increases during the acute remodelling of tissue which occurs in the involuting uterus. Plasminogen activator activity was measured by an indirect method based on the hydrolysis of the chromogenic substrate S-2251 by PA-generated plasmin. At the time of parturition the control level of PA activity was 0.033 +/- 0.018 (S.D.) mumol/4 mg uterine wet weight per 30 min. This activity increased fourfold to a peak of 0.131 +/- 0.036 at 3 days post partum, and then it declined steadily towards the control level during the next 7 days. Concomitantly, uterine weight decreased to 25% of the control weight by 3 days post partum, and it continued to decrease until day 15. In the 30 days post partum during which PA activity was monitored there was no significant change in plasmin inhibitors in the uterine extracts. The results suggest a correlation between PA activity and the process of tissue remodelling which occurs during involution of the rat uterus. This increase in PA might serve to activate a latent collagenase since the measured peak in PA activity happens to coincide with a reported increase in collagenolytic activity in the involuting rat uterus.
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