The endothelial microenvironment in the venous valvular sinus: thromboresistance trends and inter-individual variation.

The valve sinuses of the deep venous system are frequent sites of venous thrombus initiation. We previously reported that, in comparison with the non-valvular lumenal endothelium, the valve sinus endothelium had decreased expression of von Willebrand factor (vWF) and increased expression of endothelial protein C receptor (EPCR) and thrombomodulin (TM), suggesting alteration in the procoagulant/anticoagulant balance. We hypothesized that increased stasis in the deeper recesses of the venous valves would be associated with a gradient of increased thromboresistance. Expression of EPCR, TM, and vWF was analyzed via quantitative confocal immunofluorescence in residual saphenous veins collected following coronary artery bypass procedures. In agreement with our hypothesis, endothelial expression of vWF in the valve sinus decreased from the uppermost to the deepest region of the valve sinus. In contrast to our hypothesis, EPCR expression decreased from the uppermost to the deepest region of the valve sinus (p < 0.001) and TM expression remained unchanged throughout the valve sinus. Comparison of the non-valvular lumenal endothelium with the valve sinus endothelium demonstrated significantly decreased vWF expression (p < 0.001) in the valvular sinus consistent with our previous report; however, we did not observe statistically significant differences in EPCR or TM expression in this comparison. In addition, remarkable inter-individual variation in expression of these three proteins was also observed. These findings suggest that the genesis of these observations is more complex than predicted by our initial hypothesis, likely due, at least in part, to the complex rheology of the valvular sinus microenvironment.

Mechanisms and mitigating factors for venous thromboembolism in chronic kidney disease: the REGARDS study.

Essentials Chronic kidney disease (CKD) is associated with procoagulant and inflammatory biomarkers. We studied the association of CKD and venous thromboembolism (VTE) in a case-cohort study. Factor VIII, D-dimer and C-reactive protein appeared to explain the association of CKD and VTE. Statin use was protective against VTE in those with and without CKD. SUMMARY: Background Chronic kidney disease (CKD) is associated with venous thromboembolism (VTE) risk via unknown mechanisms. Whether factors associated with reduced VTE risk in the general population might also be associated with reduced VTE risk in CKD patients is unknown. Objectives To determine whether thrombosis biomarkers attenuate VTE risk, and whether factors associated with reduced VTE risk are similarly effective in CKD patients. Methods Baseline biomarkers were measured in a cohort (294 VTE cases; 939 non-cases) from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a nationwide prospective cohort study of 30 239 persons aged ≥45 years with 4.3 years of follow-up. The hazard ratio (HR) of VTE per 10 mL min-1 1.73 m-2 decrease in estimated glomerular filtration rate (eGFR), and the percentage attenuation of this HR by each biomarker, were calculated. Associations of protective factors (physical activity, lower body mass index [BMI], and aspirin, warfarin and statin use) with VTE were estimated in those with and without CKD. Results The HR for VTE with lower eGFR was 1.13 (95% confidence interval [CI] 1.02-1.25), and VTE risk was attenuated by 23% (95% CI 5-100) by D-dimer, by 100% (95% CI 50-100) by factor VIII, and by 15% (95% CI 2-84) by C-reactive protein. Normal BMI was associated with lower VTE risk in those without CKD (HR 0.47, 95% CI 0.32-0.70), but not in those with CKD (HR 1.07, 95% CI 0.51-2.22). Statin use, physical activity and warfarin use were associated with lower VTE risk in both groups. Conclusions Procoagulant and inflammatory biomarkers mediated the association of eGFR with VTE. Higher physical activity, statin use and warfarin use mitigated VTE risk in those with CKD and those without CKD, but normal BMI did not mitigate VTE risk in CKD patients.

Hemostasis biomarkers and incident cognitive impairment: the REGARDS study.

Essentials Cognitive disorders are increasing and vascular risk factors play a role in this. We performed a nested case control study of hemostasis biomarkers and cognitive impairment (CI). Higher baseline fibrinogen, factor VIII and D-dimer were related to incident CI over 3.5 years. Adjusted for other risk factors, 2+ abnormal markers (but not single ones) led to higher risk. SUMMARY: Background Vascular risk factors are associated with cognitive impairment, a condition that imposes a substantial public health burden. We hypothesized that hemostasis biomarkers related to vascular disease would be associated with the risk of incident cognitive impairment. Methods We performed a nested case-control study including 1082 participants with 3.5 years of follow-up in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a longitudinal cohort study of 30 239 black and white Americans aged ≥ 45 years. Participants were free of stroke or cognitive impairment at baseline. Baseline D-dimer, fibrinogen, factor VIII and protein C levels were measured in 495 cases who developed cognitive impairment during follow-up (based on abnormal scores on two or more of three cognitive tests) and 587 controls. Results Unadjusted odds ratios (ORs) for incident cognitive impairment were 1.32 (95% confidence interval [CI] 1.02-1.70) for D-dimer > 0.50 µg mL-1 , 1.83 (95% CI 1.24-2.71) for fibrinogen > 90th percentile, 1.63 (95% CI 1.11-2.38) for FVIII > 90th percentile, and 1.10 (95% CI 0.73-1.65) for protein C < 10th percentile. There were no differences in associations by race or region. Adjustment for demographic, vascular and health behavior risk factors attenuated these associations. However, having at least two elevated biomarkers was associated with incident cognitive impairment, with an adjusted OR of 1.73 (95% CI 1.10-2.69). Conclusion Elevated D-dimer, fibrinogen and FVIII levels were not associated with the occurrence of cognitive impairment after multivariable adjustment; however, having at least two abnormal biomarkers was associated with the occurrence of cognitive impairment, suggesting that the burden of these biomarkers is relevant.

A genetic basis for the interrelation of coagulation factors.

BACKGROUND: Evidence found in the literature for a strong correlation between coagulation factors suggests that single genes might influence the plasma concentrations of multiple coagulation factors (i.e. pleiotropically acting genes). OBJECTIVE: To determine whether there is a genetic basis for the correlation among coagulation factors by assessing the heritability of interrelated coagulation factors. PATIENTS/METHODS: We performed principal components analysis, and subsequently variance components analysis, to estimate the heritability of principal components of coagulation factors in family members of a large French-Canadian kindred. RESULTS: Four clusters were identified by principal components analysis in 200 family members who did not carry the protein C 3363C mutation. Cluster 1 consisted of prothrombin, factor VII (FVII), FIX, FX and protein S; cluster 2 consisted of FV, FIX, protein C and tissue factor pathway inhibitor; cluster 3 consisted of FVIII and von Willebrand factor; and cluster 4 consisted of antithrombin, protein C and FVII. The heritability of the principal components estimated by variance components analysis was, respectively, 37%, 100%, 37%, and 37%. CONCLUSION: Our findings support the hypothesis that genes can influence plasma levels of interrelated coagulation factors.

Chronic venous abnormalities in symptomatic and asymptomatic protein C deficiency.

BACKGROUND: Thrombophilia is a frequent medical condition associated with symptomatic deep vein thrombosis (DVT). Unlike other clinical risk factors associated with DVT, such as surgery, thrombophilia has not been demonstrated to be associated with asymptomatic venous thrombotic events. Our aim was to search for asymptomatic sequelae of DVT in a protein C (PC)-deficient family. METHODS: We studied 228 individuals from a large kindred with PC deficiency and performed a systematic ultrasound examination. RESULTS: Among the 203 patients without a known history of venous thrombosis we found seven patients with abnormalities indicative of prior asymptomatic thrombosis: six (7.4%) in the PC-deficient group (n = 81) and only one (0.8%) in the non-deficient group (n = 122). The relative risk for these sequelae associated with PC deficiency was 9.0 (95% CI: 1.1-73.7). CONCLUSIONS: These data suggest that chronic venous abnormalities are frequently present and that thrombotic events in asymptomatic individuals with familial PC deficiency may be underestimated.

Central venous catheters and upper extremity deep vein thrombosis in medical inpatients: the Medical Inpatients and Thrombosis (MITH) Study.

BACKGROUND: Upper extremity deep vein thrombosis (UEDVT) is an increasingly recognized complication in medical inpatients, with few data available regarding the incidence, risk factors and association with central venous catheter (CVC) use. METHODS: Between 2002 and 2009 all cases of hospital-acquired venous thromboembolism (VTE) at a university hospital were frequency matched 1 : 2 to non-cases without VTE by admission year and medical service. Records were abstracted to identify, characterize and assess risk factors for UEDVT. Weighted logistic regression was used to calculate odds ratios (ORs) for UEDVT associated with use of a CVC, adjusting for known VTE risk factors. RESULTS: Two hundred and ninety-nine cases of VTE complicated 64 034 admissions to medical services (4.6 per 1000 admissions). UEDVT constituted 51% (91/180) of all deep vein thrombosis (DVT), for an incidence of 1.4 per 1000 admissions (95% confidence interval [CI], 0.8-1.7). There were 247 CVCs placed per 1000 admissions (95% CI, 203-292). The use of a CVC was associated with a 14.0-fold increased risk of UEDVT (95% CI, 5.9-33.2), but was not associated with a significantly increased risk of PE (OR, 1.3; 95% CI, 0.8-2.1). Peripherally inserted central catheters had a higher OR for UEDVT (OR, 13.0; 95% CI, 6.1-27.6) than centrally inserted central venous catheters (CICC) (OR, 3.4; 95% CI, 1.7-6.8). CONCLUSION: UEDVT is a relevant complication affecting medical inpatients, accounting for half of hospital-acquired DVTs. Use of CVCs was strongly associated with risk of UEDVT.

Inter-relation of coagulation factors and d-dimer levels in healthy individuals.

Recently, high levels of coagulation factor (F)VIII, FIX and FXI have been associated with an increased risk of venous thrombosis. For several coagulation factors a substantial hereditary component was found. If regulatory genes are located outside the clotting factor genes, they may regulate the levels of several proteins in the coagulation system. Thus levels would then cluster in individuals. The aim of the present study was to assess the inter-relation among levels of the pro- and anticoagulant proteins in the coagulation cascade. We also investigated the relation between the coagulation factors and d-dimer levels (marker of coagulation activity). All analyses were performed in healthy subjects, the control population of the Leiden Thrombophilia Study (LETS), to eliminate the influence of a prior thrombosis on the interpretation of the results (n = 466). Using principal-components analysis, a method intended to explain relationships among several correlated variables, we found a clustering between the vitamin K-dependent factors (prothrombin, VII, IX, X) and FXI and FXII. FV and FVIII clustered with fibrinogen and d-dimer. FXIII remained relatively independent of the other factors. Adding the anticoagulant factors to the analysis resulted in minor changes in the clustering pattern. The anticoagulant factors clustered together. We found relatively independent clusters within the group of pro- and anticoagulant factors, which may suggest that the genetic basis for high or low levels of factors in the coagulation system may, at least partly, lie outside the genes coding for these factors.

Genome scan of venous thrombosis in a pedigree with protein C deficiency.

Kindred Vermont II has a high frequency of venous thrombosis, occurring primarily in pedigree members with type I protein C deficiency due to a 3363 inserted (Ins) C mutation in exon 6 of the protein C gene. However, only a subset of 3363 InsC carriers have suffered thrombotic episodes, suggesting that the increased risk of thrombosis results upon the co-occurrence of 3363 InsC with a second, unknown, thrombophilic mutation that segregates independently within the pedigree. To test this hypothesis and to localize the co-occurring gene, we performed a genome scan of venous thrombosis in Kindred Vermont II. Non-parametric linkage statistics identified three potential gene locations, on chromosomes 11q23 (nominal P < 0.0001), 18p11.2-q11.2 (P < 0.0007), and 10p12 (P < 0.0003), supporting the presence of at least one additional thrombophilic mutation in the pedigree. Identification of the unknown mutation(s) promises to reveal a new genetic risk factor for thrombophilia, contribute to our understanding of the blood clotting mechanism, and expand our knowledge of the diversity of oligogenic disease.

Heritability of plasma concentrations of clotting factors and measures of a prethrombotic state in a protein C-deficient family.

BACKGROUND: Earlier studies found strong support for a genetic basis for regulation of coagulation factor levels and measures of a prethrombotic state (d-dimer, prothrombin fragment 1.2). OBJECTIVES: Estimation of how much of the variation in the levels of coagulation factors and measures of a prethrombotic state, including measures of protein C activation and inactivation, could be attributed to heritability and household effect. PATIENTS AND METHODS: Blood samples were collected from 330 members of a large kindred of French-Canadian origin with type I protein C deficiency. Heritability and common household effect were estimated for plasma concentrations of prothrombin, factor (F)V, factor VIII, factor (F)IX, fibrinogen, von Willebrand factor (VWF), antithrombin, protein C, protein S, protein Z, protein Z-dependent protease inhibitor (ZPI), fibrinopeptide A (FPA), protein C activation peptide (PCP), activated protein C-protein C inhibitor complex (APC-PCI), activated protein C-alpha1-antitrypsin complex (APC-alpha1AT), prothrombin fragment 1.2 (F1.2) and d-dimer, using the variance component method in sequential oligo-genic linkage analysis routines (SOLAR). RESULTS: The highest heritability was found for measures of thrombin activity (PCP and FPA). High estimates were also found for prothrombin, FV, FIX, protein C, protein Z, ZPI, APC-PCI and APC-alpha1AT. An important influence of shared household effect on phenotypic variation was found for VWF, antithrombin, protein S and F1.2. CONCLUSIONS: We found strong evidence for the heritability of single coagulation factors and measures of a prethrombotic state. Hemostatic markers with statistically significant heritability constitute potential targets for the identification of novel genes involved in the control of quantitative trait loci.

Diagnostic accuracy of a rural live video telepathology system.

Accuracy of diagnoses rendered using a live video telepathology network was assessed for permanent sections of surgical pathology specimens. To determine accuracy, telepathology diagnoses were compared with those obtained by directly viewing the glass slide using a standard microscope. A total of 294 cases were read via both telepathology and glass slide by attending pathologists at a tertiary care medical center. Overall accuracy was defined as exact concordance between diagnoses. Clinically insignificant differences in diagnoses were excluded to determine clinically significant accuracy. For the 285 cases with complete data, the overall accuracy for telepathology was 0.912 (95% confidence interval [CI], 0.872-0.941), whereas the overall accuracy for glass slide readings was 0.968 (95% CI, 0.939-0.985). This difference is statistically significant (p = 0.009). When focusing on clinically significant discrepancies, where the difference in diagnosis might affect therapeutic decisions, the video accuracy was only slightly less than the glass slide accuracy (0.965 [95% CI, 0.934-0.982] vs. 0.982 [95% CI, 0.957-0.994], respectively), but this difference is not statistically significant (p = 0.302). Most of the cases with clinically significant differences involved lesions with inherently high interobserver variation. Certainty of diagnosis did not differ between video and glass slide readings (p = 0.911), but there was an association between certainty of diagnosis and diagnostic accuracy for video (p = 0.003 for clinically significant accuracies). Based on these findings, we recommend when using this telepathology system that only preliminary diagnoses should be given in the following situations: for diagnostic areas with known high interobserver variability; when the consultant has any degree of uncertainty about the presence or absence of the lesion in question; and when there is insufficient experience using telepathology as a diagnostic medium.

Longitudinal stability of coagulation, fibrinolysis, and inflammation factors in stored plasma samples.

We sought to assess the longitudinal stability of risk factors for atherosclerosis and thrombosis. including several coagulation. fibrinolysis, and inflammation factors, in frozen plasma samples stored at -70 degrees C for months or years. We reviewed data collected on 29 different control pools over periods ranging from 7 to 59 months for two functional assays (factor VII and fibrinogen) and seven antigen measurements (C-reactive protein. D-dimer, plasmin-alpha2-antiplasmin complex, plasminogen activator inhibitor-1, protein C, protein S, and tissue plasminogen activator), totaling more than 15,000 data points. Screening of the data using least squares regression revealed only sporadic associations between monthly means and time, with no consistent trends. Analysis by repeated measures and summary measure methods revealed no evidence of sample degradation over time for the factors studied. Our finding of longitudinal stability in the biochemical properties of frozen plasma strengthens the presumption of sample stability on which molecular epidemiologic studies are based.

Genetic screening of candidate genes for a prothrombotic interaction with type I protein C deficiency in a large kindred.

The incomplete penetrance of thrombosis in familial protein C deficiency suggests disease occurs when this deficit is combined with additional abnormalities in the hemostatic system. The pattern of inherited thrombophilia in the Vermont II kindred, which is affected by a clinically dominant type I protein C deficiency, provides strong evidence for a second unidentified gene that segregates independently of protein C deficiency and increases susceptibility to thrombosis. To test the second gene hypothesis, thirty-four candidate genes for proteins involved in hemostasis or inflammation were tested as the unknown defect, using highly polymorphic short tandem repeat (STR) markers in an informative subset (n = 31) of the kindred. The genes considered are; alpha-fibrinogen, beta-fibrinogen, gamma-fibrinogen, prothrombin, tissue factor, factor V, protein S, complement component 4 binding protein, factor XI, factor XII, factor XIIIa, factor XIIIb, histidine rich glycoprotein, high molecular weight kininogen, kallikrein, von Willebrands factor, platelet factor 4, thrombospondin, antithrombin III, alpha-1-antitrypsin, thrombomodulin, plasminogen, tissue plasminogen activator, urokinase plasminogen activator, plasminogen activator inhibitor-1, plasminogen activator inhibitor-2, protein C inhibitor, alpha-2-plasmin inhibitor, kallistatin, lipoprotein a, interleukin 6, interleukin 1, cystathionine-beta-synthase, and methylenetetrahydrofolate reductase. Mutations in many of these genes have been previously established as independent risk factors for thrombosis. However, linkage analysis provided no evidence to implicate any of the candidate genes as the second inherited factor that promotes thrombophilia in this kindred.

The G20210A prothrombin polymorphism is not associated with increased thromboembolic risk in a large protein C deficient kindred.

Likelihood analysis was used to test the effect of the G20210A prothrombin mutation and the His107Pro protein C mutation (resulting from a C insertion) on thrombosis status and prothrombin level in a large kindred of French Canadian descent with type I protein C deficiency. Genotypes were available on 279 pedigree members or their spouses. Of this total, 36 pedigree members were heterozygous for the G20210A variant and one pedigree member was homozygous for G20210A, while 64 were heterozygous for the His107Pro protein C mutation. The factor V Leiden mutation (Arg506Gln) was observed in only one of 181 tested family members. Objectively verified thrombosis was present in 26 of the 279 pedigree members. Thrombosis was suspected in an additional 19 pedigree members. The transmission disequilibrium test of Spielman, 1996, as extended to pedigrees, was used to test for excess transmission of G20210A or His107Pro to thrombosis cases, with transmission of 0.5 specifying no effect. Although the His107Pro mutation was over transmitted (0.837 +/- 0.075 p <0.001) to thrombosis cases in this pedigree, the G20210A variant was not (0.491 +/- 0.130 NS). Measured genotype analysis was used to examine a total of 184 individuals for the relationship between prothrombin level and both the G20210A variant and thrombosis. The G20210A variant increased prothrombin level from 97 +/- 2% to 124 +/- 4% (p <0.0001), but thrombosis status was not associated with any additional increase in prothrombin level. Thus, in a large thrombophilic, protein C deficient kindred, with the G20210A variant present in a proportion (13%) far higher than the general Caucasian population (approximately 2%), neither the presence of the variant nor the plasma concentration of prothrombin were associated with increased risk for thrombosis. These findings contrast with those of others who have established the G20210A variant as a thrombophilic risk factor; and emphasize the complex nature of the multigenic pathogenesis of thrombophilia.

Evidence of a founder effect for the protein C gene 3363 inserted C mutation in thrombophilic pedigrees of French origin.

We have previously reported that the 3363 inserted (Ins) C mutation in exon 6 of the protein C gene was present in four unrelated French patients and in four French Canadian families with type I protein C deficiency as well as in a large Vermont protein C deficient kindred of French Canadian origin. The present study was designed to investigate the likelihood of the existence of a founder effect for this mutation in protein C deficient individuals of French origin living in France, Quebec and Vermont. In order to demonstrate a possible founder effect for the 3363 InsC mutation, we have previously constructed a high-resolution genetic map to locate several highly polymorphic markers close to the protein C locus. Thereafter, the markers D2S347, D2S2339, D2S383, D2S2271 and D2S2215 were genotyped in 117 heterozygotes from France (n = 7), Quebec (n = 36) or Vermont (n = 74). The allelic frequency distribution of these five markers was also determined in fifty control French Canadian subjects and thirty-two unaffected members of the Vermont kindred with normal protein C levels and compared with their frequency in our cohort of heterozygotes. Our data suggest that patients from Quebec and Vermont carry a common haplotype at the protein C locus. Moreover, in order to study the evolutionary history of the 3363 InsC mutation, we traced back the ascending genealogy of one proband in each of the families with this mutation. These results showed that the 3363 InsC mutation was most probably introduced in North America by a couple of French settlers who established themselves in 1669 on Isle d'Orleans located near Quebec City. All heterozygotes for the 3363 InsC mutation living in North America are related to these founders within 10 generations. Thus, these families afford a unique opportunity to evaluate the role of the protein C system in thrombophilia due to the high degree of linkage disequilibrium at the protein C gene, which in essence holds that variable more constant than in a more heterogeneous population.

Cancer case-control studies with other cancers as controls.

Theoretical considerations concerning the use of other cancer patients as controls in cancer case-control studies are reviewed. Selection bias may be a problem in that some other cancers may be caused by the exposure under study biasing the odds ratio towards unity. Such bias is noted to be greatest with low prevalence exposures associated with high attributable risks for other cancers. However, it may be possible to identify selection bias with other cancer controls using census or other general population data. In addition, using other cancers as controls has important advantages with regard to recall and interviewer bias, which may be of unknown magnitude and direction when using general population controls. A further disadvantage of general population controls is that separate selection of decreased controls should usually be made for deceased cases, whereas a mixture of live and deceased controls can be expected when selecting other cancer patients as controls. Since there are also logistical and cost advantages in using other cancer patients as controls, this study design is likely to be used increasingly in the future, particularly in cancer registry settings.

Plasma levels of factors II, VII and X and their relationship to the international normalized ratio during chronic warfarin therapy.

Monitoring of oral anticoagulant therapy is usually undertaken with the prothrombin time (PT), which is influenced by factors II, X, and VII. A number of studies have suggested that the prothrombin (factor II) level may be the most important determinant of the therapeutic efficacy of these drugs. Although some studies suggest that oral anticoagulants induce a similar residual level of plasma vitamin K-dependent proteins, others have called this into question. We therefore measured plasma levels of factors II, X, and VII in 50 patients undergoing chronic Warfarin therapy. The plasma levels of factors II, X, and VII were significantly different. Although the factor X levels of all plasmas were < 30%, levels of factors II and VII were > 30% in 14% and 50% of the samples, respectively. Multivariable analysis showed factor II levels to be the least significant of the three factors measured in determining the international normalized ratio of plasma or whole blood. Thus, plasma levels of the vitamin K-dependent coagulation factors are not equal in patients on chronic Warfarin therapy. If factor II (prothrombin) levels are indeed the major determinants of the therapeutic efficacy of Warfarin, alternative means of monitoring that more accurately reflects prothrombin levels should be evaluated.

Characterization of the human prostaglandin H synthase 1 gene (PTGS1): exclusion by genetic linkage analysis as a second modifier gene in familial thrombosis.

Genetic evidence from a large Vermont kindred indicates that an unknown gene promotes thrombosis when inherited in conjunction with type I protein C deficiency. Cyclooxygenase-1 [prostaglandin H synthase 1 gene (PTGS1)] was tested as a plausible candidate for the unknown gene because of its role in primary hemostasis. The complete sequence of PTGS1 (25 638 nucleotides) was determined from a 37 kb human genomic cosmid clone to characterize intronic regions and subsequently to allow the search for mutations by direct sequencing of genomic DNA. Northern blot analysis confirms usage of a newly described distal poly-adenylation signal. Short tandem repeat (STR) sequences found in intron 2 and the 3' flanking region were developed as new genetic markers for PTGS1. The position of PTGS1 was refined on the CHLC chromosome 9 linkage map using the new markers scored in four Centre d'Etude du Polymorphisme Humain families and multipoint linkage analysis. Direct sequencing of DNA from members of the Vermont kindred led to the discovery of two new single nucleotide polymorphisms (SNPs) that give rise to non-conservative amino acid changes in the signal peptide (Arg(8) to Trp and Pro(17) to Leu) of cyclooxygenase-1. Linkage analysis of the SNP and STR markers indicated that PTGS1 is not the interacting gene associated with an increased incidence of thrombosis in the Vermont kindred.

Effects of long-term storage on salivary thiocyanate concentration.

The stability of thiocyanate (SCN) concentration in frozen saliva samples stored for up to one year was examined. Fifteen adult smokers and five adult nonsmokers each provided six saliva samples, which were analyzed in duplicate pairs after 0, 2, and 12 months of storage at -20 degrees C in airtight containers. No significant changes in average SCN levels occurred over the storage interval. Although within-subject variability for duplicate samples analyzed at the same time was high, the mean levels in regular smokers were significantly higher than the levels in nonsmokers.

Inflammation and peripheral venous disease. The San Diego Population Study.

The inflammatory response to healing in venous thrombosis might cause vein damage and post-thrombotic syndrome. Inflammation may also be involved in venous insufficiency apart from deep-vein thrombosis. We studied the association of inflammation markers with venous insufficiency in a general population sample. We characterised 2,404 men and women in a general population cohort for peripheral venous disease and its severity using physical exam, symptom assessment, and venous ultrasound. Inflammation markers, C-reactive protein (CRP), fibrinogen, interleukin 1-beta (IL-1-beta), IL-8, IL-10, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, monocyte chemoattractant-1 (MCP-1) and vascular endothelial cell growth factor (VEGF) were compared in 352 case participants with peripheral venous disease and 352 controls with no venous abnormalities frequency matched to cases by age, sex and race. Associations were also evaluated including a subset of 108 cases of severe venous disease, as previously defined. Odds ratios (95% CI), for peripheral venous disease for biomarkers in the top quartile (adjusting for age, race, sex, body mass index and history of venous thrombosis) were 1.8 (1.1-3.0), 1.6 (1.0-2.5) and 1.5 (0.9-2.3) for CRP, fibrinogen and IL-10, respectively. Associations were larger considering cases of severe venous disease, with odds ratios for these three analytes of 2.6 (1.2-5.9), 3.1 (1.3-7.3) and 2.2 (1.1-4.4), and for IL-8: 2.4 (1.1-5.2). There was no association of IL-1-beta, ICAM-1, VCAM-1, E-selectin, MCP-1 or VEGF with overall cases or severe venous disease. In conclusion, a subset of inflammation markers were associated with increased risk of peripheral venous disease, suggesting potential therapeutic targets for treatment.

Venous thrombosis risk assessment in medical inpatients: the medical inpatients and thrombosis (MITH) study.

BACKGROUND: We sought to define the risk factors present at admission for venous thromboembolism (VTE) in medical inpatients and develop a risk model for clinical use. METHODS: Between January 2002 and June 2009, 299 cases of hospital-acquired VTE were frequency matched to 601 controls. Records were abstracted using a standard form for characteristics of the thrombosis, medical conditions and other risk factors. Weighted logistic regression and survey methods were used to develop a risk model for hospital-acquired VTE that was validated by bootstrapping. RESULTS: VTE complicated 4.6 per 1000 admissions. Two risk assessment models were developed, one using laboratory data available at admission (Model 1) and the other excluding laboratory data (Model 2). Model 1 consisted of the following risk factors (points): history of congestive heart failure (5), history of inflammatory disease (4), fracture in the past 3 months (3), history of VTE (2), history of cancer in the past 12 months (1), tachycardia (2), respiratory dysfunction (1), white cell count ≥ 11 × 10(9) /L (1), and platelet count ≥ 350 × 10(9) /L (1). Model 2 was similar, except respiratory dysfunction had 2 points and white cell and platelet counts were removed. The c-statistic for Model 1 was 0.73 (95% CI 0.70, 0.77) and for Model 2 0.71 (95% CI 0.68, 0.75). CONCLUSIONS: We present a VTE risk assessment model for use in medical inpatients. The score is simple and relies on information known at the time of admission and typically collected in all medical inpatients. External validation is needed.