No differences in support of thrombin generation by neonatal or adult platelets

Newborns have, despite low clotting factors and poor in vitro platelet function, a well functioning hemostasis. The reason for this is still not completely clear. The aim of our study was to investigate whether phospholipids in neonatal platelets differ from those in adult platelets in their total amount, in their exposure on the platelet surface, and their effect on thrombin generation (TG).

METHODS

Clotting times of newborn and adult platelet-rich plasma were measured. Effect of newborn and adult platelets on TG was measured by means of CAT (calibrated automated thrombography). In addition, the effect of newborn and adult platelets with or without stimulation by ionophor on TG was measured in a purified prothrombinase complex. Phosphatidylserine-exposure (PS) of newborn and adult platelets was measured by flow cytometry of annexin V binding. The amount of phospholipids (PL) was determined by means of mass spectrometry.

RESULTS

Clotting times of platelet-rich plasma (PRP) of newborns stimulated with ionophor showed a significant lower reduction of clotting time than in adult PRP. No differences in the support of TG between neonatal and adult platelets were found in neonatal or adult plasma by means of CAT. In the purified system TG was increased by adding ionophor stimulated platelets but no difference was evident between stimulated newborn and adult platelets. Flow cytometric analysis showed no difference in annexin V binding between adult and newborn platelets. The results of mass spectrometry showed a very similar amount and pattern of PL of adult and newborns platelets.

CONCLUSION

Our results do not provide any evidence that a different PL content or expression of neonatal platelets may alter TG in neonates.

Screening for haemorrhagic disorders in paediatric patients by means of a questionnaire

AIM

In children, screening for haemorrhagic disorders is further complicated by the fact that infants and young children with mild disease in many cases most likely will not have a significant history of easy bruising or bleeding making the efficacy of a questionnaire even more questionable.

PATIENTS, METHODS

We compared the questionnaires of a group of 88 children in whom a haemorrhagic disorder was ruled out by rigorous laboratory investigation to a group of 38 children with mild von Willebrand disease (VWD). Questionnaires about child, mother and father were obtained prior to the laboratory diagnosis on the occasion of routine preoperative screening.

RESULTS

23/38 children with mild VWD showed at least one positive question in the questionnaire, while 21/88 without laboratory signs showed at least one positive question. There was a trend to more specific symptoms in older children. Three or more positive questions were found only in VWD patients, but only in a few of the control group. The question about menstrual bleeding in mothers did not differ significantly. Sensitivity of the questionnaire for a hemostatic disorder was 0.60, while specifity was 0.76. The negative predictive value was 0.82, but the positive predictive value was only 0.52.

CONCLUSIONS

Our small study shows, that a questionnaire yields good results to exclude a haemostatic disorder, but is not a sensitive tool to identify such a disorder.

Calibrated automated thrombin generation in paediatric patients with inflammatory bowel disease

In adults, inflammatory bowel disease (IBD) is associated with an increased risk of thromboembolic complications. The pathogenesis of IBD is not really clear and a high thrombin activity might contribute to disease progression. We wanted to see whether children with IBD have a higher thrombin generation (TG).

PATIENTS, MATERIAL, METHODS

Plasma samples were collected of 20 patients with IBD and of 60 healthy controls (age range from 10 to 19). TG was measured by means of Calibrated automated thrombography (CAT). The disease activity was estimated, using the Pediatric Crohn's Disease Activity Index (PCDAI) for Crohn's disease and the Pediatric Ulcerative Colitis Disease Activity Index (PUCAI) for Ulcerative Colitis. In addition, we investigated F1+F2, TAT, TFPI and fibrinogen.

RESULTS

There was a significant increase of endogenous thrombin potential (ETP), lag time and time to peak in patients with IBD, while peak showed no difference to healthy controls. ETP and F1+F2 in children with IBD also showed a significant correlation with PCDAI (PUCAI) and fibrinogen.

CONCLUSION

IBD in children is associated with high TG, but this seems to be caused mainly by the inflammatory process and not by any individual disposition.

Malignant stroke in an adolescent with a homozygous MTHFR 677CT mutation and intake of hormonal contraceptives

Severe stroke in children and adolescents with its devastating long term consequences remains a rare disorder with many open questions. Beside the well known risk factors such as infection or congenital and acquired heart disease, coagulation disorders have to be considered in the differential work up of the underlying aetiology. Here we report the case of an adolescent with a homozygote MTHFR 677CT mutation suffering a malignant stroke shortly after the start of oral contraceptives.

CONCLUSION

Since prevention seems easily feasible, general screening for MTHFR mutations might be worthwhile in women before starting oral contraceptives.

Glucans as biological response modifiers

Beta-D-glucans belong to a group of natural, physiologically active compounds, generally called biological response modifiers. Glucans represent highly conserved structural components of cell walls in yeast, fungi, or seaweed. Despite long history of research, the exact mechanisms of glucan action remain unsolved. The present review starts with the history of glucans. Next, the detailed information about the possible glucan sources is followed by a description of the mechanisms of action. Physiological functions of glucan suggest the possible use of glucans not only as non-specific immunomodulator, but also as its possible future use as a drug.

Beta-glucans, history, and the present: immunomodulatory aspects and mechanisms of action

The present paper represents a comprehensive up-to-date review of beta -glucans, their chemical and biological properties, and their role in immunological reactions. beta -D-Glucans belong to a group of physiologically active compounds called biological response modifiers and represent highly conserved structural components of cell walls in yeast, fungi, or seaweed. Despite almost 150 years of research, the exact mechanisms of their action remain unclear. The present review starts with the history of glucans. Next, attention is focused on sources and structure, comparing the effects of physicochemical properties, and sources on biological effects. As glucans belong to natural products useful in preventing various diseases, they have been highly sought after throughout human history. Based on extensive recent research, this paper explains the various mechanisms of effects and the ways glucans mediate their effects on defense reactions against infections. Despite the fact that predominately pharmacological effects of glucans are positive, their unfavorable and potentially toxic side effects were not overlooked. In addition, attention was focused on the future research, possible alternatives such as synthetic oligosaccharides, and on clinical applications.

Malignant stroke in an adolescent with a homozygous MTHFR 677CT mutation and intake of hormonal contraceptives

Severe stroke in children and adolescents with its devastating long term consequences remains a rare disorder with many open questions. Beside the well known risk factors such as infection or congenital and acquired heart disease, coagulation disorders have to be considered in the differential work up of the underlying aetiology. Here we report the case of an adolescent with a homozygote MTHFR 677CT mutation suffering a malignant stroke shortly after the start of oral contraceptives. Conclusion: Since prevention seems easily feasible, general screening for MTHFR mutations might be worthwhile in women before starting oral contraceptives.

Toll-like receptors TLR1, TLR2 and TLR4 gene mutations and natural resistance to Mycobacterium avium subsp. paratuberculosis infection in cattle

Toll like receptors (TLRs) are a class of pattern recognition receptors belonging to the innate immune system. Mutations in the protein coding region of TLRs are associated with altered responsiveness to pathogen-associated molecular patterns (PAMPs). A search was performed for novel mutations in bovine TLR1, TLR2 and TLR4 genes associated with the Mycobacterium avium subsp. paratuberculosis (MAP) infection. The work was also focused on the assessment of linkage between well known mutations in TLR genes (TLR2: Arg677Trp, Pro681His and Arg753Gln; TLR4: Asp299Gly and Thr399Ile), and the susceptibility of cattle to MAP infection. Detection of MAP infection in cattle population (n=711) was based on IS900 PCR, which revealed 22.50% (n=160) MAP positivity. Known mutations in TLR2 and TLR4 genes were not found in cattle population. A novel mutation Val220Met was associated (Odd's ratio, OR-3.459) with increased susceptibility to MAP infection. Toll/interleukin-1 receptor (TIR) domain of TLR2 was screened for the presence of mutations, wherein a novel Ile680Val mutation was linked with MAP infection. In silico analysis of the bovine TLR4 ectodomain (ECD) revealed the polymorphic nature of the central ECD and irregularities in the central LRR motifs. LRR11 of the TLR4 showed five missense mutations possibly linked with the increased susceptibility to MAP infection. The most critical position that may alter the pathogen recognition of TLR molecule was 4th residue downstream to LRR domain. Two such missense mutations in TLR4 (Asp299Asn downstream to LRR11, and Gly389Ser downstream to LRR15) were associated with MAP infection. Briefly, the work describes novel mutations in the bovine TLRs and presents their association with the MAP infection.

Enhanced thrombin generation in plasma of severe thrombocytopenic patients due to rFVIIa

RFVIIa-enhanced thrombin generation has been shown to be dependent on platelets. In previous work we have shown that addition of monocytes and rFVIIa to microparticle free plasma causes a distinct thrombin generation. The aim of our study has been to examine whether there is enough surface provided by microparticles in thrombocytopenic plasma to allow an effect of rFVIIa.

PATIENTS, METHODS

Thrombin generation was measured in platelet rich plasma (PRP) and microparticle free plasma (MFP) of thrombocytopenic haemato-oncological patients with and without addition of rVIIa by means of calibrated automated thrombography. Microparticles were analyzed in PRP by FACS flow cytometry.

RESULTS

Microparticle free plasma showed no thrombin generation with or without addition of rFVIIa. Addition of rFVIIa to PRP of thrombocytopenic patients led to a significant shortening of lag time and time to peak in thrombin generation, while ETP and peak remained unchanged.

CONCLUSION

Our results show that even in plasma of severe thrombocytopenic patients enough surface may be provided by microparticles to allow an enhancement of thrombin generation by rFVIIa.

Internal carotid artery surgery in regional anesthesia at the Clinic of Surgery in Pilsen during the past 5 years

A low percentage of perioperative complications and excellent long-term outcome following carotid artery surgery in Vascular Centers demonstrate the priority of surgical solutions in patients with significant findings on carotid arteries, in the prevention and treatment of ischemic cerebrovascular accidents. The group of patients from the Clinic of Surgery in Pilsen demonstrates the benefits of regional anesthesia during internal carotid artery surgery, both in terms of the patients' health and the financial costs incurred by the hospital.

Molecular characterization and measurement of Alzheimer's disease pathology: implications for genetic and environmental aetiology

The neuropathological changes seen in Alzheimer's disease represent an interaction between the ageing process in which normal intellectual function is retained, and changes which are specifically associated with severe cognitive deterioration. Molecular analysis of these changes has tended to emphasize the distinction between neurofibrillary pathology, which is intracellular and highly correlated with cognitive deterioration, and the changes associated with the deposition of extracellular amyloid, which appears to be widespread in normal ageing. Extracellular amyloid deposits consist of fibrils composed of a short 42 amino acid peptide (beta/A4) derived by abnormal proteolysis from a much larger precursor molecule (APP). The recent demonstration of a mutation associated with APP in rare cases with familial dementia, neurofibrillary pathology in the hippocampus and atypical cortical Lewy body pathology raises the possibility that abnormal processing of APP could be linked directly with neurofibrillary pathology. Neurofibrillary tangles and neuritic plaques are sites of dense accumulation of pathological paired helical filaments (PHFs) which are composed in part of an antigenically modified form of the microtubule-associated protein tau. The average brain tissue content of PHFs measured biochemically does not increase in the course of normal ageing but increases 10-fold relative to age-matched controls in patients with Alzheimer's disease. There is also a substantial (three-fold) disease-related decline in normal soluble tau protein relative to age-matched controls. This intracellular redistribution of a protein essential for microtubule stability in cortico-cortical association circuits may play an important part in the molecular pathogenesis of dementia in Alzheimer's disease. The role of abnormal proteolysis of APP in this process remains to be elucidated. Immunohistochemical studies on renal dialysis cases have failed to detect evidence of neurofibrillary pathology related to aluminium accumulation in brain tissue. Nevertheless it needs to be seen whether more sensitive biochemical assays of neurofibrillary pathology can demonstrate evidence of an association with aluminium.

Anemia is associated with mortality in kidney-transplanted patients--a prospective cohort study

Although anemia is a known risk factor of mortality in several patient populations, no prospective study to date has demonstrated association between anemia and mortality in kidney-transplanted patients. In our prospective cohort study (TransQol-HU Study), we tested the hypothesis that anemia is associated with mortality and graft failure (return to dialysis) in transplanted patients. Data from 938 transplanted patients, followed at a single outpatient transplant center, were analyzed. Sociodemographic parameters, laboratory data, medical history and information on comorbidity were collected at baseline. Data on 4-year outcome (graft failure, mortality or combination of both) were collected prospectively from the patients' charts. Both mortality and graft failure rate during the 4-year follow-up was significantly higher in patients who were anemic at baseline (for anemic vs nonanemic patients, respectively: mortality 18% vs. 10%; p < 0.001; graft failure 17% vs 6%; p < 0.001). In multivariate Cox proportional hazard models the presence of anemia significantly predicted mortality (HR = 1.690; 95% CI: 1.115-2.560) and also graft failure (HR = 2.465; 95% CI: 1.485-4.090) after adjustment for several covariables. Anemia, which is a treatable complication, is significantly and independently associated with mortality and graft failure in kidney-transplanted patients.

Cardiac resynchronization therapy. Midterm follow-up of 128 patients

OBJECTIVE

Cardiac resynchronization therapy has been used in the treatment of advanced heart failure with inter- and intraventricular dyssynchrony for more than ten years.

AIM OF THE STUDY

A retrospective study was conducted to assess midterm results of biventricular (BiV) pacing in cardiac resynchronization therapy.

METHODS

128 consecutive patients (age 61.0+/-9.6, 98 males), with heart failure NYHA class 2.9+/-0.4 (2.5-3.5), with LBBB, QRS> or =130 ms, with dilated cardiomyopathy--DCM (86), with coronary artery disease--CAD (36), with both these etiologies (4) and with valvular disease (2) had a BiV PM (82) or BiV ICD (46) implanted in 2000-2007. AV delay was optimized individually, using echocardiography. Before and 3 months after implantation, the following was established: NYHA class, LVEF (echocardiographically), maximum oxygen uptake (spiroergometrically), left ventricle diastolic diameter and mitral regurgitation. The average follow-up time was 25.8+/-20.8 months. Complications and 2-year survival (n=68) were also assessed.

RESULTS

1) After 3 months of BiV pacing, NYHA class improved from 2.9+/-0.4 to 2.4+/-0.6 (n=99, p<0.001), LVEF increased from 20.2+/-4.9 to 23.9+/-6.6 % (n=92, p<0.001). Left ventricle diastolic diameter decreased from 69.8+/-8 to 67.5+/-10.0 mm (n=88, p=0.001) and mitral regurgitation was reduced from 2.2+/-0.9 to 1.9+/-0.9 (n=87, p=0.001) and maximum oxygen uptake during spiroergometry increased from 14.5+/-2.7 to 15.5+/-2.6 ml/min/kg (n=52, p=0.005). 2) Coronary sinus lead reposition was done in 2.3 %, epicardial lead implantation in 4.7 %, atrial lead reposition in 2.3 %, and right ventricular lead reposition in 2.3 % of patients. Contralateral reimplantation due to inflammatory complications in 1.6 % of patients. 3) Heart transplantation was performed on 9 patients. 4) Two-year survival was recorded in 77.9 % of 68 followed patients (72.2 % in CAD, 79.6 % in DCM).

CONCLUSION

In the retrospective study of patients with BiV pacing a decline in heart failure, an increase in cardiac pump efficiency, reverse remodelling of left ventricle and acceptable occurrence of complications were confirmed (Tab. 4, Fig. 7, Ref. 18). Full Text (Free, PDF) www.bmj.sk

Practical way to assess metabolic syndrome using a continuous score obtained from principal components analysis

AIMS/HYPOTHESIS

We devised a practical continuous score to assess the metabolic syndrome, and assessed whether this syndrome score predicts incident diabetes and cardiovascular disease.

SUBJECTS AND METHODS

Among 5,024 participants of the Data from an Epidemiological Study on the Insulin Resistance Syndrome (D.E.S.I.R.) cohort, we defined a metabolic syndrome score by the first principal component (PC1), using only the correlations between continuous metabolic syndrome measures (glucose, waist circumference, triglycerides, and systolic blood pressure). This metabolic syndrome score was highly correlated with a similar score also including insulin and HDL cholesterol (r ( s )=0.94). Over 9 years of follow-up, incident diabetes and cardiovascular disease (CVD) were predicted by logistic regression using the simpler metabolic syndrome score.

RESULTS

The means of the metabolic syndrome measures differed between men and women. Nevertheless, as the degree of variance explained and the PC1 coefficients were remarkably similar, we used a common metabolic syndrome score. The metabolic syndrome score explained 50% of the variance of the metabolic syndrome measures, and waist circumference had the highest correlation (0.59) with this score. Each standard deviation increase in the metabolic syndrome score was associated with a markedly increased age-adjusted risk of developing diabetes (odds ratios: men 3.4 [95% CI 2.6-4.4]; women 5.1 [3.6-7.2]) and with increased incident CVD of 1.7 (1.4-2.1) in men and 1.7 (1.0-2.7) in women.

CONCLUSIONS/INTERPRETATION

Our results, which should be confirmed in other populations, suggest that it is possible to evaluate the risk of the metabolic syndrome in a pragmatic fashion with a continuous score, obtained from principal components analysis of the basic, continuous syndrome measures.