Increased markers of thrombogenesis in chronic atrial fibrillation: effects of warfarin treatment

OBJECTIVE: To determine whether chronic atrial fibrillation is associated with abnormalities in plasma fibrinogen, von Willebrand factor (vWF) (a marker of endothelial disturbance), or fibrin D- dimer (a measure of fibrin turnover); and if so, whether such levels are related to haemodynamic disturbance (enlarged left atrium, poor left ventricular function) or existing treatment with warfarin or aspirin. To investigate the effects of introducing warfarin in patients with atrial fibrillation on fibrinogen and D- dimer levels. DESIGN: Cross sectional population sample controlled study and longitudinal study of patients undergoing anticoagulation. SETTING: District general hospital. SUBJECTS: 87 patients (44 men and 43 women of mean (SEM) age 63.0 (1.0)) with chronic atrial fibrillation. At the time of the study, 37 were taking no antithrombotic medication (group 1), 31 were taking warfarin (including two on warfarin and aspirin) (group 2) and 19 were taking aspirin alone (group 3). They were compared with 158 population controls from a random population sample (the second Glasgow monitoring trends and determinants in cardiovascular disease study). As part of clinical treatment warfarin was introduced in 20 patients with chronic atrial fibrillation (14 men and six women of mean (SEM) (range) age 63.9 (2.35 (32-74) years). RESULTS: Plasma fibrinogen remained significantly increased in patients of group 1 (no antithrombotic medication) compared with that of the population controls (median difference 1.23 g/l; 95% confidence interval (CI) 0.88 to 1.62, P < 0.0001). There was also a significant increase in plasma D-dimer levels (median difference 77 ng/ml; 95% CI 38 to 122, P < 0.01) and vWF (median difference 63 IU/dl; 95% CI 38 to 89, P < 0.0001). There was no significant difference in plasma fibrinogen (median difference 0.14 g/l; 95% CI -0.44 to 0.77, P = 0.65) or vWF (median difference 3.5 IU/dl; 95% CI - 41 to 41, P = not significant in patients of group 2 (warfarin treatment) compared with that of patients in group 1. Levels of D-dimer were significantly lower in group 2 (median difference 90 ng/ml, 95% CI 39 to 150, P < 0.0001) than in group 1. There were no significant differences in plasma fibrinogen (median difference 0.08 g/l; 95% CI - 0.52 to 0.77, P = 0.73), D-dimer (median difference - 34 ng/ml; 95% CI - 114 to 21.0, P = 0.25), or vWF (median difference 2%; 95% CI - 35 to 41, P = not significant) levels between patients of groups 1 and 3. There were no significant correlations between the coagulation indices and left atrial volume or ventricular function. There was a significant positive correlation between plasma fibrin D-dimer and vWF levels in patients of groups 1 and 3 (r = 0.52, P < 0.001). There was a significant reduction in median plasma fibrin D-dimer levels at 2 months after the introduction of warfarin (181 ng/ml v 80 ng/ml, P < 0.001), but no effect on plasma fibrinogen. CONCLUSIONS: Increased median plasma fibrinogen and vWF levels were found in patients with chronic atrial fibrillation. Plasma D-dimer levels were also increased in patients with chronic atrial fibrillation not receiving warfarin, suggesting increased intravascular thrombogenesis in such patients. Introduction of warfarin normalised circulating fibrin D- dimer levels, suggesting that warfarin treatment was effective in preventing excessive fibrin turnover, consistent with the antithrombotic effects of warfarin. These results suggest three possible thrombotic markers to assess patients with atrial fibrillation who are at high risk of thrombogenesis; D-dimer also merits assessment as a measure of reduction in thrombotic risk in patients receiving warfarin.     

TGF-beta 1 induces the cyclin-dependent kinase inhibitor p27Kip1 mRNA and protein in murine B cells

TGF-beta1 inhibits the cell cycle progression of many types of cells by arresting them in the G1 phase. This cell cycle arrest has been attributed to the regulatory effects of TGF-beta1 on both the levels and the activities of the G1 cyclins and their kinase partners. The activities of these kinases are negatively regulated by a number of proteins, such as p15INK4b, p21WAF1/Cip1, and p27Kip1, that physically associate with cyclins, cyclin-dependent kinases (Cdk), or cyclin-Cdk complexes. In epithelial cell lines, TGF-beta1 was previously shown to inhibit cell cycle progression through down-regulation of Cdk4 and/or up-regulation of p15INK4b and/or p21WAF1/Cip1. However, TGF-beta1 had little or no effect on the p27Kip1 mRNA and protein levels. In this report, we show that, in contrast to observations in epithelial cell lines, TGF-beta1 increased the p27Kip1 mRNA and protein levels in the murine B cell lines CH31 and WEHI231. This TGF-beta1-mediated induction of p27Kip1 also resulted in an increased association of p27Kip1 with Cdk2 and a decreased Cdk2 kinase activity. In contrast to epithelial cells, however, TGF-beta1 had little or no effect on the Cdk4 and p21WAF1/Cip1 protein levels in these B cells. Finally, although several studies suggested a direct role of p53 in TGF-beta1-mediated cell cycle arrest in epithelial cells, TGF-beta1 inhibited cell cycle progression in CH31 even in the absence of wild-type p53. Taken together, these results suggest that TGF-beta1 induces G1 arrest in B cells primarily through a p53-independent up-regulation of p27Kip1 protein.     

Subpubic sinus: a remnant of cloaca

A 14-month-old girl had purulent discharge from a sinus over the subpubic region for 2 weeks. Radiography and voiding cystourethrography revealed a 4.5 cm. long fistula extending to the retropubic region without any connection to the lower urinary tract. The fistula was excised. Histological findings revealed that the fistula had 3 different types of epithelium: stratified squamous, transitional and columnar. Clinical and pathological findings indicated that the sinus was most likely a remnant of the cloaca.     

Leukotriene B4 and interleukin-8 in human immunodeficiency virus-related pulmonary disease

STUDY OBJECTIVE: To investigate the pathogenesis of lung injury in Pneumocystic carinii pneumonia and nonspecific interstitial pneumonitis (NIP), common pulmonary complications of human immunodeficiency virus (HIV) infection. The efficacy of corticosteroid therapy in P carinii pneumonia and the observation that bronchoalveolar lavage (BAL) neutrophilia predicts a poor prognosis support the premise that the lung injury of P carinii pneumonia is due to the host's inflammatory response to the infection. DESIGN: In vitro measurements on previously collected BAL fluid samples. SETTING: The Clinical Center of the National Institutes of Health, a research hospital and tertiary care referral center. PATIENTS: Five normal volunteers, 5 asymptomatic HIV-positive patients, 10 HIV-positive patients with NIP (5 asymptomatic and 5 with respiratory symptoms), and 19 HIV-positive patients with P carinii pneumonia. MEASUREMENTS AND RESULTS: BAL leukotriene B4 (LTB4), interleukin 8 (IL-8), and phospholipase A2 (PLA2) were measured. IL-8 and PLA2 were elevated in patients with P carinii pneumonia, and IL-8 correlated with BAL fluid absolute neutrophil count. LTB4, IL-8, and PLA2 levels were elevated in patients with NIP; LTB4 and PLA2 levels correlated with absolute neutrophil count, and IL-8 correlated with alveolar-arterial oxygen pressure difference. IL-8 was elevated in the asymptomatic HIV-positive patients, and there was a trend toward elevation of PLA2 in this group. CONCLUSION: IL-8 appears to play a role in the pathogenesis of lung injury in P carinii pneumonia and may be the principal neutrophil chemotaxin in this disease; PLA2 may also be involved in the pathogenesis of P carinii pneumonia. Both LTB4 and IL-8 may be involved in the recruitment of neutrophils and subsequent lung injury of NIP. These data suggest that there are varying mechanisms by which inflammatory cells are recruited to the lung in different HIV-related lung diseases.     

The hindfoot alignment view

A modification of Cobey's method for radiographically imaging the coronal plane alignment of the hindfoot is described. Using this view, we estimated the moment arm between the weightbearing axis of the leg and the contact point of the heel. Normative data on 57 asymptomatic adult subjects are presented. The weightbearing line of the tibia falls within 8 mm of the lowest calcaneal point in 80% of subjects and within 15 mm of the lowest calcaneal point in 95% of subjects. The technique for measuring coronal plane hindfoot alignment is reliable, with an interobserver correlation coefficient of 0.97. This radiographic technique should help in the evaluation of complex hindfoot malalignments.