Immediate effects of individualized heparin and protamine management on hemostatic activation and platelet function in adult patients undergoing cardiac surgery with tranexamic acid antifibrinolytic therapy

Objective:

This randomized prospective study was initiated to clarify whether individualized heparin and protamine dosing has immediate effects on hemostatic activation and platelet function in adult cardiac surgery.

Methods:

Sixty adults undergoing elective coronary artery bypass grafting (CABG) were assigned to receive individualized heparin and protamine (HMS group, n= 29) or a standard dose (ACT group, n=24). Measures of thrombin generation and Multiplate® (Verum Diagnostica, Munich, Germany) platelet function tests were performed before and after cardiopulmonary bypass (CPB).

Results:

HMS patients received higher heparin (p = 0.006) and lower protamine (p<0.001) doses. Post-CPB, HMS managed patients showed significantly lower thrombin generation (thrombin-antithrombin (TAT) p<0.02) than the ACT group. Moreover, HMS managed patients had a better preservation of platelet function (COL p = 0.013; ADP p = 0.04; TRAP p = 0.04).

Conclusion:

An individualized and stable heparin concentration and appropriate dosing of protamine can reduce thrombin generation and preserve platelet function, even in short-time CPB.

Molecular pharmacological profile of a novel thiazolinone-based direct and selective 5-lipoxygenase inhibitor

BACKGROUND AND PURPOSE

The potency of many 5-lipoxygenase (5-LOX) inhibitors depends on the cellular peroxide tone and the mechanism of 5-LOX enzyme activation. Therefore, new inhibitors that act regardless of the mode of enzyme activation need to be developed. Recently, we identified a novel class of thiazolinone-based compounds as potent 5-LOX inhibitors. Here, we present the molecular pharmacological profile of (Z)-5-(4-methoxybenzylidene)-2-(p-tolyl)-5H-thiazol-4-one, compound C06.

EXPERIMENTAL APPROACH

Inhibition of 5-LOX product formation was determined in intact cells [polymorphonuclear leukocytes (PMNL), rat basophilic leukaemia-1, RAW264.7] and in cell-free assays [homogenates, 100, 000×g supernatant (S100), partially purified 5-LOX] applying different stimuli for 5-LOX activation. Inhibition of peroxisome proliferator-activated receptor (PPAR), cytosolic phospholipase A(2) (cPLA(2) ), 12-LOX, 15-LOX-1 and 15-LOX-2 as well as cyclooxygenase-2 (COX-2) were measured in vitro.

KEY RESULTS

C06 induced non-cytotoxic, direct 5-LOX inhibition with IC(50) values about 0.66 µM (intact PMNL, PMNL homogenates) and approximately 0.3 µM (cell-free PMNL S100, partially purified 5-LOX). Action of C06 was independent of the stimulus used for 5-LOX activation and cellular redox tone and was selective for 5-LOX compared with other arachidonic acid binding proteins (PPAR, cPLA(2) , 12-LOX, 15-LOX-1, 15-LOX-2, COX-2). Experimental results suggest an allosteric binding distinct from the active site and the C2-like domain of 5-LOX.

CONCLUSIONS AND IMPLICATIONS

C06 was identified as a potent selective direct 5-LOX inhibitor exhibiting a novel and unique mode of action, different from other established 5-LOX inhibitors. This thiazolinone may possess potential for intervention with inflammatory and allergic diseases and certain types of cancer.

[Protein glycation as a pathological mechanism in diabetes]

The incidence of diabetes has increased in the recent years. Diabetes is characterized by increased sugar concentrations in the blood. Due to this dysregulation, more carbohydrate-induced modification of proteins - so-called advanced glycation end products (AGEs) - are formed endogenously by non-enzymatic reactions. These are discussed to be at least in part responsible for diabetes-associated diseases. The accumulation of AGEs in the tissue can be used as a biomarker for patient outcome. In contrast, the effects of the uptake of AGEs from nutrition are still unclear.

RAGE influences obesity in mice. Effects of the presence of RAGE on weight gain, AGE accumulation, and insulin levels in mice on a high fat diet

BACKGROUND

The metabolic syndrome is defined by the presence of obesity, insulin resistance, dyslipidemia, and hypertension. Advanced glycation end products (AGEs) are stable end products of the Maillard reaction, whereby AGE accumulation is considered not only a biomarker of aging but is also associated with several degenerative diseases. AGEs are recognized by several receptor molecules of which the receptor of AGEs (RAGE) is currently the most intensively studied receptor. Activation of RAGE causes an unfavorable proinflammatory state and deletion of RAGE in diabetic animals has been reported to protect against atherosclerosis. AGEs and a high fat diet are associated with cardiovascular diseases, whereas is still not clear whether a direct link between high fat nutrition and AGEs exists in vivo.

MATERIALS AND METHODS

C57BL/6 and C57BL/6 RAGE -/- mice were fed a high fat diet to induce obesity. Weight, insulin, lipid levels, AGE modifications, and cardiac gene expression were analyzed.

RESULTS

The absence of RAGE resulted in accelerated weight gain, increased plasma cholesterol, and higher insulin levels in obese mice. The hearts of normal and obese RAGE -/- mice contained lower levels of the AGE arginine-pyrimidine and 3DG-imidazolone than RAGE + / + animals. RAGE -/- mice also exhibited lower expression of the genes encoding the antioxidative enzymes MnSOD, Cu/ZnSOD, and ceruloplasmin in cardiac tissue, whereas the AGE receptors AGER-1, -2, and -3 were equally expressed in both genotypes. Obese mice of both strains expressed increased amounts of AGER-2. Only obese RAGE + / + mice exhibited a reduced mRNA accumulation of Cu/Zn SOD.

CONCLUSION

These data suggest that RAGE is involved in the development of obesity and insulin resistance.

The importance of genetic variants in TNFα for periodontal disease in a cohort of coronary patients

AIM

The aim of this analysis was to evaluate the importance of genetic variants of TNFα for the severity of periodontal disease and periodontal risk factors with respect to periodontal risk factors in a cohort of coronary patients.

SUBJECTS

A total of 942 consecutive patients with angiographic proven coronary heart disease were prospectively included in the study entitled "Periodontitis and Its Microbiological Agents as Prognostic Factors in Patients With Coronary Heart Disease" (ClinicalTrials.gov identifier:NCT01045070).

METHODS

After including of patients, an extensive periodontal examination also involving PCR-sampling for 11 periodontal bacteria was performed. In this subanalysis, single nucleotide polymorphisms (SNPs) c.-308G>A, c.-238G>A and haplotypes for TNFα were analysed by CTS-PCR-SSP Tray kit (Heidelberg, Germany).

RESULTS

The AG+AA genotype of SNP c.-238G>A of TNFα gene was associated with the amount of clinical attachment loss in patients with coronary heart disease in multivariate regression analysis. Moreover, Prevotella intermedia occurred more frequently in carriers who were positive for the AG+AA genotype and A-allele of SNP c.-308G>A in bivariate and multivariate analyses. Furthermore, only in bivariate analyses significant associations of genetic variants of TNFα with intensified bleeding on probing and with higher plasma level of interleukin 6 could be shown.

CONCLUSIONS

Genetic variants of TNFα gene, namely c.-308G>A and c.-238G>A, are associated with periodontal conditions in patients with coronary heart disease.

Statins potently reduce the cytokine-mediated IL-6 release in SMC/MNC cocultures

Inflammatory pathways are involved in the development of atherosclerosis. Interaction of vessel wall cells and invading monocytes by cytokines may trigger local inflammatory processes. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are standard medications used in cardiovascular diseases. They are thought to have anti-inflammatory capacities, in addition to their lipid-lowering effects. We investigated the anti-inflammatory effect of statins in the cytokine-mediated-interaction-model of human vascular smooth muscle cells (SMC) and human mononuclear cells (MNC). In this atherosclerosis-related inflammatory model LPS (lipopolysaccharide, endotoxin), as well as high mobility group box 1 stimulation resulted in synergistic (i.e. over-additive) IL-6 (interleukin-6) production as measured in ELISA. Recombinant IL-1, tumour necrosis factor-α and IL-6 mediated the synergistic IL-6 production. The standard anti-inflammatory drugs aspirin and indomethacin (Indo) reduced the synergistic IL-6 production by 60%. Simvastatin, atorvastatin, fluvastatin or pravastatin reduced the IL-6 production by 53%, 50%, 64% and 60%, respectively. The inhibition by the statins was dose dependent. Combination of statins with aspirin and/or Indo resulted in complete inhibition of the synergistic IL-6 production. The same inhibitors blocked STAT3 phosphorylation, providing evidence for an autocrine role of IL-6 in the synergism. MNC from volunteers after 5 day aspirin or simvastatin administration showed no decreased IL-6 production, probably due to drug removal during MNC isolation. Taken together, the data show that anti-inflammatory functions (here shown for statins) can be sensitively and reproducibly determined in this novel SMC/MNC coculture model. These data implicate that statins have the capacity to affect atherosclerosis by regulating cytokine-mediated innate inflammatory pathways in the vessel wall.

Image rejects/retakes--radiographic challenges

A general held position among radiological personnel prior to digitalisation was that the problem of image rejects/retakes should more or less vanish. However, rejects/retakes still impose several challenges within radiographic imaging; they occupy unnecessary resources, expose patients to unnecessary ionizing radiation and may also indicate suboptimal quality management. The latter is the main objective of this paper, which is based on a survey of international papers published both for screen/film and digital technology. The digital revolution in imaging seems to have reduced the percentage of image rejects/retakes from 10-15 to 3-5 %. The major contribution to the decrease appears to be the dramatic reduction of incorrect exposures. At the same time, rejects/retakes due to lack of operator competence (positioning, etc.) are almost unchanged, or perhaps slightly increased (due to lack of proper technical competence, incorrect organ coding, etc.). However, the causes of rejects/retakes are in many cases defined and reported with reference to radiographers' subjective evaluations. Thus, unless radiographers share common views on image quality and acceptance criteria, objective measurements and assessments of reject/retake rates are challenging tasks. Interestingly, none of the investigated papers employs image quality parameters such as 'too much noise' as categories for rejects/retakes. Surprisingly, no reject/retake analysis seems yet to have been conducted for direct digital radiography departments. An increased percentage of rejects/retakes is related to 'digital skills' of radiographers and therefore points to areas for extended education and training. Furthermore, there is a need to investigate the inter-subjectivity of radiographers' perception of, and attitude towards, both technical and clinical image quality criteria. Finally, there may be a need to validate whether reject/retake rate analysis is such an effective quality indicator as has been asserted.

No effect of the PPAR-gamma agonist rosiglitazone on ACTH or cortisol secretion in Nelson's syndrome and Cushing's disease in vitro and in vivo

OBJECTIVE

Surgical tumor resection remains the primary treatment strategy in ACTH-secreting pituitary adenomas, i.e. Cushing's disease (CD) and Nelson's syndrome (NS). However, an effective long-term pharmacological regime is not available in patients with persistent ACTH-hypersecretion. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-gamma) is abundantly expressed in most pituitary adenomas. First encouraging data reported that the PPAR-gamma ligand rosiglitazone antagonizes ACTH hypersecretion and exerts also antiproliferative effects in pituitary cell lines. Herein, we studied the potential therapeutical effects of rosiglitazone in patients with ACTH-secreting pituitary adenomas in vitro and in vivo.

MATERIALS AND METHODS

Seven patients with persistent ACTH-hypersecretion (3 with NS, 4 with persistent CD) were treated 5 months with rosiglitazone (4 - 16 mg/day). In vitro assays were performed in primary cell cultures obtained from eight additional patients with ACTH-secreting pituitary adenomas applying 80 microM rosiglitazone repeatedly over a time period of 14 days.

RESULTS

Our long-term clinical trial with the PPAR-gamma activator rosiglitazone showed no amelioration of clinical symptoms nor an inhibiting effect on ACTH-secretion in vivo. In vitro, rosiglitazone treatment led to a statistically significant decrease of ACTH levels in 2 out of 8 primary cell cultures after 14 days compared to untreated controls.

CONCLUSION

In contrast to the initially promising laboratory data gathered in pituitary cell line experiments and nude mice models, our experimental data obtained in primary human ACTH-expressing pituitary adenoma cell cultures as well as our clinical experience with a long-term rosiglitazone trial in approved antidiabetic doses support the recently reported disappointing reports on acute or short-term medical treatment of ACTH-hypersecretion with PPAR-gamma activators.

Fallacies in the arguments for new technology: the case of proton therapy

In a seminal article in the Journal of Medical Ethics, Søren Holm and Tuja Takala analysed two protechnology arguments in bioethics: the hopeful principle and the automatic escalator. They showed how these arguments relate to problematic arguments such as the precautionary principle and the empirical slippery slope argument, and argued that they should be used with great caution. The present article investigates the recent debate on proton beam therapy, where the hopeful principle and the automatic escalator are identified. However, the debate reveals a series of other arguments that deserve similar caution. An analysis of these arguments indicates that the roots of their fallacies are to be found in the ignorance of the uncertainties about risks and benefits and an overly optimistic attitude towards technology and progress. The point is not to argue against proton therapy, but rather to point out that flawed arguments for new technologies, such as proton therapy, can actually hamper their implementation instead of promoting it. Patients deserve the best technology available, not only on the basis of the best available evidence, but also on the basis of the best arguments.

Blood platelet behaviour in patients with a type I diabetes mellitus

Platelets appear to be involved in the development of vascular diseases in diabetic patients. In a number of studies, platelet adhesion and aggregation has been found to be enhanced in diabetic patients indicating a platelet hyperreactivity. However, contradictory results on hyperreactivity of diabetic platelets towards agonists published in the literature leading to the problem of reliability of agonist-induced aggregation as a parameter which is able to reflect an altered platelet reactivity. Therefore, we introduced the quantification of actin filaments of platelets as an early indicator of platelet hyperreactivity. In 20 patients with type I diabetes mellitus agonist-induced aggregation, spontaneous aggregation, malondialdehyde (MDA)-formation, plasma lipid status and the ability of plasma to degrade platelet activating factor (PAF) as well as the G- to F-actin equilibrium of platelets were assayed. Compared to an age- and sex-matched control group F-actin values, spontaneous aggregation and PAF-hydrolase were significantly increased in diabetic patients.