OFAGE banding patterns of different yeast genera and of intergeneric hybrids

Electrophoretic karyotypes of yeasts belonging to the species Saccharomyces cerevisiae, Kluyveromyces marxianus and Candida macedoniensis were established by means of OFAGE. Hybrids between S. cerevisiae and K. marxianus as well as between K. marxianus and C. macedoniensis were analyzed by comparing their OFAGE-banding-pattern with the parental banding-patterns. Thus, evidence for exchanges of intact chromosomes and for chromosomal rearrangements could be gained on a molecular level.     

Activated protein C decreases plasminogen activator-inhibitor activity in endothelial cell-conditioned medium

Confluent cultures of endothelial cells from human umbilical cord were used to study the effect of activated human protein C (APC) on the production of plasminogen activators, plasminogen activator-inhibitor, and factor VIII-related antigen. Addition of APC to the cells in a serum-free medium did not affect the production of tissue-type plasminogen activator (t-PA) or factor VIII-related antigen; under all measured conditions, no urokinase activity was found. However, less plasminogen activator-inhibitor activity accumulated in the conditioned medium in the presence of APC. This decrease was dose dependent and could be prevented by specific anti-protein C antibodies. No decrease was observed with the zymogen protein C or with diisopropylfluorophosphate-inactivated APC. APC also decreased the t-PA inhibitor activity in endothelial cell-conditioned medium in the absence of cells, which suggests that the effect of APC is at least partly due to a direct effect of APC on the plasminogen activator- inhibitor. High concentrations of thrombin-but not of factor Xa or IXa-- had a similar effect on the t-PA inhibitor activity. The effect of APC on the plasminogen activator-inhibitor provides a new mechanism by which APC may enhance fibrinolysis. The data suggest that activation of the coagulation system may lead to a secondary increase of the fibrinolytic activity by changing the balance between plasminogen activator(s) and its (their) fast-acting inhibitor.     

Increased urinary albumin excretion, endothelial dysfunction, and chronic low-grade inflammation in type 2 diabetes: progressive, interrelated, and independently associated with risk of death

In 328 type 2 diabetic patients followed for 9.0 years (mean), we investigated whether endothelial dysfunction and chronic inflammation (estimated from plasma markers) can explain the association between (micro)albuminuria and mortality. Of the patients, 113 died. Mortality was increased in patients with baseline microalbuminuria or macroalbuminuria (odds ratios as compared with normoalbuminuria, 1.78 [P < 0.05] and 2.86 [P < 0.01]) and in patients with soluble vascular cell adhesion molecule 1 in the third tertile and C-reactive protein in the second and third tertiles (odds ratios as compared with the first tertile, 2.05 [ P < 0.01], and 1.80 [P < 0.05] and 2.92 [ P < 0.01]). These associations were mutually independent. The mean yearly change in urinary albumin excretion was 9.4%; in von Willebrand factor, 8.1%; in tissue-type plasminogen activator, 2.8%; in soluble vascular cell adhesion molecule 1, 5.2%; in soluble E-selectin, -2.3%; in C-reactive protein, 3.8%; and in fibrinogen, 2.3%. The longitudinal development of urinary albumin excretion was significantly and independently determined by baseline levels of and the longitudinal development of BMI, systolic blood pressure, serum creatinine, glycated hemoglobin and plasma von Willebrand factor (baseline only), soluble E-selectin (baseline only), tissue-type plasminogen activator, C-reactive protein, and fibrinogen. The longitudinal developments of markers of endothelial function and inflammation were interrelated. In type 2 diabetes, increased urinary albumin excretion, endothelial dysfunction, and chronic inflammation are interrelated processes that develop in parallel, progress with time, and are strongly and independently associated with risk of death.     

The central roles of obesity-associated dyslipidaemia, endothelial activation and cytokines in the Metabolic Syndrome--an analysis by structural equation modelling

HYPOTHESIS: The multi-faceted components of the metabolic syndrome now include markers of inflammation and endothelial activation. Despite this growing body of epidemiological data, standard statistical methods fail to evaluate the nature of these associations adequately. In this pilot study, we hypothesize that obesity may lead to endothelial activation which is in part mediated by dyslipidaemia and proinflammatory cytokines. These factors interact to give rise to hyperinsulinaemia, hypertension and an anti-fibrinolytic state. To test this hypothesis, we used confirmatory factor analysis and structural equation modelling to fit these data to a model designed on theoretical grounds. METHODS: Metabolic syndrome variables, cytokines (IL6 and TNFalpha), markers of inflammation and endothelial activation were measured in 107 Caucasian non-diabetic subjects aged 40-75 y. Using confirmatory factor analysis, we identified six factors to represent composite measurements of blood pressure, obesity, dyslipidaemia, hyperinsulinaemia, endothelial activation and the anti-fibrinolytic state. We fitted these variables to two separate models, one using IL-6 and the other TNFalpha as the cytokine, and examined the inter-relationships (path analysis) amongst these variables, based on the above hypothesis. RESULTS: Men were centrally more obese and had increased markers of endothelial activation, inflammation and the anti-fibrinolytic state as well as hyperinsulinaemia and dyslipidaemia, compared with women. Obesity indexes (both body mass index and waist-hip ratio) were strongly associated with multiple cardiovascular risk factors. Both IL6 and TNFalpha were correlated with age, male gender, obesity indexes and markers of endothelial activation. Only IL-6 was associated with smoking while TNFalpha was correlated with hyperinsulinaemia. In the TNFalpha model, 61% of the obesity variance was explained by male gender, 36% of TNFalpha variance by age and dyslipidaemia, 43% of dyslipidaemia variance by age and obesity, 33% of hyperinsulinaemia variance by dyslipidaemia and a non-smoking state, 29% of anti-fibrinolytic state variance by hyperinsulinaemia, 65% of endothelial activation variance by TNFalpha, dyslipidaemia and hyperinsulinaemia, 34% of blood pressure variance by hyperinsulinaemia and endothelial activation. In the IL-6 model, we observed similar relationships except that 23% of IL6 variance was explained by smoking and age. CONCLUSIONS: Using confirmatory factor analysis and structural equation modelling, we found that obesity, dyslipidemia and cytokines were the principal explanatory variables for the various components of the metabolic syndrome, with IL6 and TNFalpha having different explanatory variables and effects. These complex inter-relationships were in part mediated by hyperinsulinaemia and endothelial activation. While this hypothetical model was based on scientific evidence, supported by rigorous analysis, it requires further confirmation in large-scale prospective studies. Given the complexity of the biological system and its interactions with exogenous factors, structural equation modelling provides a useful scientific tool for hypothesis testing, complementary to the more traditional experimental and cohort studies.     

Unopposed estrogen increases total plasma factor VII, but not active factor VII--a short-term placebo-controlled study in healthy postmenopausal women

Estrogen therapy may increase the risk of arterial thromboembolism, at least in the short term. In a randomized, double-blind and placebo-controlled study in 25 healthy postmenopausal women (52.5 +/- 2.8 years), we therefore examined the short-term effect of unopposed estrogen on the fasting and fat-load-stimulated plasma levels of total factor VII versus active factor VII. Plasma total factor VII was measured by use of a chromogenic assay; plasma active FVII by a recently developed method using truncated tissue factor. As compared to placebo, 8 weeks of oral 17beta-estradiol (2 mg daily) increased the mean fasting and postprandial plasma levels of total factor VII by 17 and 21% points, respectively (both P < 0.01 ), but did not affect the fasting and/or postprandial plasma levels of active factor VII (mean change both 0.05 ng/mL; P > 0.35). Furthermore, the change in the fasting level of total factor VII after therapy was not associated with the change in the fasting level of active factor VII (r = 0.27; P = 0.21). These findings argue against the idea that elevated levels of total factor VII underlie an increased risk of arterial thromboembolism in postmenopausal women using unopposed estrogen replacement.     

Impaired procoagulant-anticoagulant balance during hormone replacement therapy? A randomised, placebo-controlled 12-week study

In this randomised, placebo-controlled 12-week study, sixty healthy postmenopausal women received either placebo (N = 16) or daily 2 mg micronised oestradiol, either unopposed (N = 16, E2 group) or combined with a progestagen for 14 days of each cycle (N = 28, E2+P group). RESULTS: As compared to placebo, plasma levels of AT III were reduced only in the E2 group (approximately 28%), plasma levels of protein C decreased only in the E2+P group (approximately 4%) and plasma levels of protein S decreased in both the E2 and E2+P group (approximately 21%). In both the E2 and E2+P groups, the plasma levels of factor VII (antigen and activity) showed a borderline significant increase (approximately 10%), whereas no significant change was observed in active factor VII. Plasma levels of tissue-type plasminogen activator (approximately 22%), urokinase plasminogen activator (approximately 25%) and plasminogen activator inhibitor type-1 (approximately 43%) decreased in the E2 and E2+P groups, whereas those of plasminogen increased (approximately 12%). Treatment was associated with an increase in levels of prothrombin fragment 1+2 (approximately 31%), but levels of thrombin-antithrombin III complexes, and of plasmin-alpha2-antiplasmin complexes and total fibrin(ogen) degradation products did not change significantly. CONCLUSION: Short-term E2 and E2+P treatment is associated with a shift in the procoagulant-anticoagulant balance towards a procoagulant state. A substantial proportion of women do not have a net increase in fibrinolytic activity. These data may be relevant in explaining the increased risk of venous thromboembolism associated with ERT and HRT, and possibly also in explaining the negative results of the Heart and Estrogen/progestin Replacement Study.