Significance of extended sports cardiology screening of elite handball referees.

The significance of cardiology screening of referees is not well established. Cardiovascular risk factors and diseases were examined in asymptomatic Hungarian elite handball referees undergoing extended screening: personal/family history, physical examination, 12-lead ECG, laboratory tests, body-composition analysis, echocardiography, and cardiopulmonary exercise testing. Holter-ECG (n = 8), blood pressure monitorization (n = 10), cardiac magnetic resonance imaging (CMR; n = 27) and computer tomography (CCT; n = 4) were also carried out if needed. We examined 100 referees (age: 29.6±7.9years, male: 64, training: 4.3±2.0 hours/week), cardiovascular risk factors were: positive medical history: 24%, overweight: 10%, obesity: 3%, dyslipidaemia: 41%. Elevated resting blood pressure was measured in 38%. Stress-ECG was positive due to ECG-changes in 16%, due to elevated exercise blood pressure in 8%. Echocardiography and/or CMR identified abnormalities in 19%. A significant number of premature ventricular contractions was found on the Holter-ECG in two cases. The CCT showed myocardial bridge or coronary plaques in one-one case. We recommended lifestyle changes in 58%, new/modified antihypertensive or lipid-lowering therapy in 5%, iron-supplementation in 22%. By our results, a high percentage of elite Hungarian handball referees had cardiovascular risk factors or diseases, which, combined with physical and psychological stress, could increase the possibility of cardiovascular events. Our study draws attention to the importance of cardiac screening in elite handball referees.

Circulating Relaxin-1 Level Is a Surrogate Marker of Myocardial Fibrosis in HFrEF.

Introduction: Relaxin-1 (RLN1) has emerged as a possible therapeutic target in myocardial fibrosis due to its anti-fibrotic effects. Previous randomized clinical trials investigated therapeutic role of exogenous relaxin in patients with acute-on-chronic heart failure (HF) and failed to meet clinical endpoints. Here, we aimed to assess endogenous, circulating RLN1 levels in patients with heart failure with reduced ejection fraction (HFrEF) of ischemic origin. Furthermore, we analyzed relation of RLN1 and left ventricular diastolic function, left and right ventricular fibrosis, and invasive hemodynamic measurements. Unique feature of our study is the availability of ex vivo human myocardial tissue. Methods: Human myocardial samples were available from the Transplantation Biobank of the Heart and Vascular Center at Semmelweis University after local ethical approval and informed consent of all participants (n = 47). Tissue was collected immediately after heart explantations; peripheral blood was collected before induction of anesthesia. Myocardial sections were stained for Masson's trichrome and Picrosirius red staining to quantify fibrosis. Medical records were analyzed (ECG, anthropometry, blood tests, medication, echocardiography, and invasive hemodynamic measurements). Results: Average RLN1 levels in HFrEF population were significantly higher than measured in age and gender matched healthy control human subjects (702 ± 283 pg/ml in HFrEF vs. 44 ± 27 pg/ml in control n = 47). We found a moderate inverse correlation between RLN1 levels and degree of myocardial fibrosis in both ventricles (r = -0.357, p = 0.014 in the right ventricle vs. r = -0.321, p = 0.028 in the left ventricle with Masson's trichrome staining). Parallel, a moderate positive correlation was found in left ventricular diastolic function (echocardiography, E/A wave values) and RLN1 levels (r = 0.456, p = 0.003); a negative correlation with RLN1 levels and left ventricular end-systolic diameter (r = -0.373, p = 0.023), and diastolic pulmonary artery pressure (r = -0.894, p < 0.001). RLN1 levels showed moderate correlation with RLN2 levels (r = 0.453, p = 0.0003). Conclusion: Increased RLN1 levels were accompanied by lower myocardial fibrosis rate, which is a novel finding in our patient population with coronary artery disease and HFrEF. RLN1 can have a biomarker role in ventricular fibrosis; furthermore, it may influence hemodynamic and vasomotor activity via neurohormonal mechanisms of action. Given these valuable findings, RLN1 may be targeted in anti-fibrotic therapeutics and in perioperative care of heart transplantation.

Impact of Test Conditions on ADP-Induced Platelet Function Results With the Multiplate Assay: Is Further Standardization Required?

BACKGROUND: Platelet function testing was suggested to help tailor P2Y12-inhibitor therapy; however, the lack of proper standardization is still a limitation. METHODS: In a prospective study, we enrolled clopidogrel-treated and P2Y12-inhibitor naive patients to investigate the influence of (1) time from blood collection, (2) stability of the stored Adenosine diphosphate (ADP) reagent, and (3) the use of enoxaparin on results of the Multiplate assay. Measurements were performed from samples kept for 0, 30, 60, 120, and 240 minutes at room temperature before processing. To determine the impact of the reagent stability, freshly thawed ADP was compared with ADP kept for 3 to 5 or 8 to 13 days at 2°C to 8°C. Finally, samples containing enoxaparin at therapeutic or prophylactic doses were compared with enoxaparin-free blood. RESULTS: A total of 180 measurements were performed. ADP-stimulated platelet reactivity values decreased significantly over time (67 ± 40 U to 68 ± 37 U to 58 ± 37 U to 45 ± 33 U to 35 ± 33 U; P < .0001). Consequently, a dramatic reduction was observed in the proportion of patients with high platelet reactivity ( P < .0001). A significant drop in platelet reactivity was observed with ADP stored for 8 to 13 days as compared to freshly thawed ADP ( P = .011). Enoxaparin triggered a slight, concentration-dependent increase in platelet reactivity ( P < .05). CONCLUSION: Test conditions may have profound impacts on the obtained results with the Multiplate assay. Our findings highlight the large influence of the time from sample collection until testing, suggesting that measurements should be performed within an hour of blood collection.

Delayed Gelatinase Inhibition Induces Reticulon 4 Receptor Expression in the Peri-Infarct Cortex.

Matrix metalloproteinase (MMP) inhibition can potentially prevent hemorrhagic transformation following cerebral infarction; however, delayed-phase MMP activity is also necessary for functional recovery after experimental stroke. We sought to identify potential mechanisms responsible for the impaired recovery associated with subacute MMP inhibition in a transient middle cerebral artery occlusion model of focal ischemia in CD rats. Gelatinase inhibition was achieved by intracerebral injection of the Fn-439 MMP inhibitor 7 days after stroke. Treatment efficacy was determined on day 9 by in situ gelatin zymography. The peri-infarct cortex was identified by triphenyl tetrazolium chloride staining, and tissue samples were dissected for TaqMan array gene-expression study. Of 84 genes known to influence poststroke regeneration, we found upregulation of mRNA for the reticulon 4 receptor (Rtn4r), a major inhibitor of regenerative nerve growth in the adult CNS, and borderline expression changes for 3 additional genes (DCC, Jun, and Ngfr). Western blot confirmed increased Rtn4r protein in the peri-infarct cortex of treated animals, and double immunolabeling showed colocalization primarily with the S100 astrocyte marker. These data suggest that increased Rtn4 receptor expression in the perilesional cortex may contribute to the impaired regeneration associated with MMP inhibition in the subacute phase of cerebral infarction.

Comprehensive study into the activation of the plasma enzyme systems during attacks of hereditary angioedema due to C1-inhibitor deficiency.

BACKGROUND: The activation of plasma enzyme systems contributes to hereditary angioedema attacks. We aimed to study the activation markers of the fibrinolytic, coagulation, and contact systems in a larger number of paired samples obtained from the same C1-INH-HAE patients in symptom-free periods and during attacks. METHODS: Eleven parameters (Factors XI, XII, and C1-inhibitor activity; the concentrations of the D-dimer, prothrombin fragments 1 + 2, plasminogen, plasminogen activator inhibitor-1 [PAI-1], thrombin-anti-thrombin III [TAT] complex, fibrinogen) were measured along with prothrombin time and activated partial thromboplastin time (aPTT), using commercial kits. We compared these markers in samples obtained from the same 39 patients during attack-free periods and during 62 edematous episodes. Forty healthy subjects of matching sex and age served as controls. RESULTS: Compared with the healthy controls, significantly higher FXI and FXII activity (p = 0.0007, p = 0.005), as well as D-dimer (p < 0.0001), prothrombin fragments 1 + 2 (p < 0.0001), and TAT (p = 0.0303) levels were ascertained in the patients during symptom-free periods. The evaluation of samples from symptom-free periods or obtained during attacks revealed the increase of FXII activity, as well as of the concentration of D-dimer, prothrombin fragments 1 + 2, and TAT during edematous episodes. PAI-1 level, prothrombin time, and aPTT decreased significantly during attacks, compared with symptom-free periods. D-dimer level was significantly higher during multiple- vs. single-site attacks. CONCLUSIONS: Comparing a large number of paired samples from symptom-free periods or from edematous episodes allowed accurate appraisal of the changes occurring during attacks. Moreover, our study pointed out that individual episodes may be characterized by different marker patterns.

Selegiline promotes NOTCH-JAGGED signaling in astrocytes of the peri-infarct region and improves the functional integrity of the neurovascular unit in a rat model of focal ischemia.

PURPOSE: Our experiments aimed at exploring potential neurorestorative mechanisms of selegiline, a compound routinely used in the treatment of Parkinson's disease and previously shown to improve the functional recovery of stroke patients. METHODS: Selegiline was administered continuously via osmotic mini-pumps between 48 and 216 hours following middle cerebral artery occlusion (MCAO) in rats. Twenty-four hours before sacrifice, the animals underwent magnetic resonance imaging (MRI). After decapitation, the peri-infarct region was dissected to perform a TAQMAN array gene expression study, and brains were fixed for immunolabeling. RESULTS: In addition to the previously known induction of anti-apoptosis genes, selegiline significantly increased the mRNA level of Notch 1 receptor and its ligand Jagged 1. Immunohistochemistry demonstrated elevated Notch 1 and Jagged 1 immunoreactivities in the peri-infarct region. Double labeling with glial markers revealed that both Notch 1 and Jagged 1 were expressed in astrocytes but not in microglia. MRI examination indicated significantly reduced edema in selegiline-treated rats compared to control MCAO rats, and increased capillary network density was found in the peri-infarct region of the selegiline-treated animals. CONCLUSION: Our results suggest that selegiline treatment enhances Notch-Jagged signaling in astrocytes, reduces peri-lesional edema and potentially helps preserve the capillary network following focal ischemia.

Signaling via PI3K/FOXO1A pathway modulates formation and survival of human embryonic stem cell-derived endothelial cells.

Vascular derivatives of human embryonic stem cells (hESC) are being developed as sources of tissue-specific cells for organ regeneration. However, identity of developmental pathways that modulate the specification of endothelial cells is not known yet. We studied phosphatidylinositol 3-kinase (PI3K)-Forkhead box O transcription factor 1A (FOXO1A) pathways during differentiation of hESC toward endothelial lineage and on proliferation, maturation, and cell death of hESC-derived endothelial cells (hESC-EC). During differentiation of hESC, expression of FOXO1A transcription factor was linked to the expression of a cluster of angiogenesis- and vascular remodeling-related genes. PI3K inhibitor LY294002 activated FOXO1A and induced formation of CD31(+) hESC-EC. In contrast, differentiating hESC with silenced FOXO1A by small interfering RNA (siRNA) showed lower mRNA levels of CD31 and angiopoietin2. LY294002 decreased proliferative activity of purified hESC-EC, while FOXO1A siRNA increased their proliferation. LY294002 inhibits migration and tube formation of hESC-EC; in contrast, FOXO1A siRNA increased in vitro tube formation activity of hESC-EC. After in vivo conditioning of cells in athymic nude rats, cells retain their low FOXO1A expression levels. PI3K/FOXO1A pathway is important for function and survival of hESC-EC and in the regulation of endothelial cell fate. Understanding these properties of hESC-EC may help in future applications for treatment of injured organs.

Pathogen sensing pathways in human embryonic stem cell derived-endothelial cells: role of NOD1 receptors.

Human embryonic stem cell-derived endothelial cells (hESC-EC), as well as other stem cell derived endothelial cells, have a range of applications in cardiovascular research and disease treatment. Endothelial cells sense Gram-negative bacteria via the pattern recognition receptors (PRR) Toll-like receptor (TLR)-4 and nucleotide-binding oligomerisation domain-containing protein (NOD)-1. These pathways are important in terms of sensing infection, but TLR4 is also associated with vascular inflammation and atherosclerosis. Here, we have compared TLR4 and NOD1 responses in hESC-EC with those of endothelial cells derived from other stem cells and with human umbilical vein endothelial cells (HUVEC). HUVEC, endothelial cells derived from blood progenitors (blood outgrowth endothelial cells; BOEC), and from induced pluripotent stem cells all displayed both a TLR4 and NOD1 response. However, hESC-EC had no TLR4 function, but did have functional NOD1 receptors. In vivo conditioning in nude rats did not confer TLR4 expression in hESC-EC. Despite having no TLR4 function, hESC-EC sensed Gram-negative bacteria, a response that was found to be mediated by NOD1 and the associated RIP2 signalling pathways. Thus, hESC-EC are TLR4 deficient but respond to bacteria via NOD1. This data suggests that hESC-EC may be protected from unwanted TLR4-mediated vascular inflammation, thus offering a potential therapeutic advantage.

High-volume lesions using a new second-generation open irrigation radiofrequency catheter are associated with the development of inhomogeneous lesions.

BACKGROUND: After catheter ablation there is often a discrepancy between acute and chronic success rates. We aimed to evaluate major determinants for lesion quality and understand different manifestations of lesion structures. METHODS: In a canine thigh muscle model radiofrequency (RF) current was delivered for 60 seconds at 30 W (n = 39) or 50 W (n = 18) with 15-g contact force. A second-generation 12-hole gold open irrigation catheter (SGIT) and a first-generation six-hole platinum-iridium catheter (FGIT; Biotronik, Berlin, Germany) were used. Electrode and tissue temperatures (at the surface and 3.5-mm and 7-mm depth) were recorded and lesion dimensions were measured. Lesions with steam pops were excluded. Histological examination was performed to evaluate homogeneity of the lesions. Inhomogeneity was defined as a visual multiband lesion pattern indicating different histological characteristics. RESULTS: In total 57 lesions were created. Seventeen lesions were excluded (steam pops) and 40 lesions were analyzed. A total number of 11 homogeneous and 29 inhomogeneous lesions were identified. Using the SGIT catheter 16.7% of the lesions was homogeneous and 83.3% inhomogeneous; for FGIT it was 43.8% and 56.2% (P = 0.065), respectively. Homogeneous lesions had lower volumes as compared to inhomogeneous lesions (514.0 ± 198.8 vs 914.8 ± 399.1 mm, P = 0.003). Multiple logistic regression analysis indicated that the SGIT catheter is a significant predictor for inhomogeneous lesions (odds ratio 6.5, 95% confidence interval 1.1-38.8; P = 0.040) independent from power setting and flow rate. CONCLUSIONS: The development of inhomogeneous lesions after acute RF ablation is associated with higher lesion volumes and the use of the second-generation irrigation gold-tip catheter.

Radiofrequency ablation at low irrigation flow rates using a novel 12-hole gold open-irrigation catheter.

BACKGROUND: High irrigation rates during radiofrequency (RF) ablation may cause fluid overload and limit lesion size. This in vivo animal study assessed the safety and efficacy of RF ablation at low irrigation rates using a novel 12-hole gold catheter. METHODS: A total of 103 lesions, created on the thigh of five mongrel dogs, were analyzed. Lesions were created using a 12-hole irrigated gold-tip (Au) and a six-hole irrigated platinum-iridium (PtIr) catheter (both 7F/3.5-mm electrode; BIOTRONIK SE & CO, KG, Berlin, Germany) in parallel and perpendicular orientation. RF current was delivered for 60 seconds at 30 W using 8 mL/min and 15 mL/min irrigation. Electrode temperature, steam pops, lesion dimensions, and coagulum formation were recorded. RESULTS: Electrode temperatures were lower for Au compared to PtIr in parallel (8 mL/min: 38.1 ± 1.7°C vs 48.0 ± 4.8°C, P < 0.0001; 15 mL/min: 36.0 ± 1.5°C vs 46.9 ± 5.4°C, P < 0.0001) and perpendicular position (15 mL/min: 35.5 ± 1.2°C vs 38.4 ± 2.5°C, P = 0.003). The number of steam pops between Au and PtIr was comparable for parallel (8 mL/min: 14% vs 27%, P = 0.65; 15 mL/min: 14% vs 43%, P = 0.21) and perpendicular orientation (8 mL/min: 25% vs 17%, P = 1.00; 15 mL/min: 18% vs 0%, P = 0.48). Au created larger volumes than PtIr at 8 mL/min irrigation (861 ± 251 mm(3) vs 504 ± 212 mm(3) , P = 0.004); however, for 15 mL/min, volumes were comparable (624 ± 269 mm(3) vs 768 ± 466 mm(3) , P = 0.46). No coagulum formation was observed for any of the catheters on the surface and catheter tip. CONCLUSION: RF ablation at low flow rate using a novel 12-hole irrigation Au catheter is safe and results in larger lesions than with a PtIr electrode.

Neuroprotective effects of estrogen treatment on ischemia-induced behavioural deficits in ovariectomized gerbils at different ages.

Although much is known about the protective effect of acute estrogen therapy in cerebral ischemia, relatively little is known about its effect on functional outcome at different ages. The impact of age is, however, important on the efficacy of steroids in the central nervous system. We investigated whether a single dose of estradiol pre-treatment would be neuroprotective in young (4 months), middle-aged (9 months) and old (18 months) female gerbils following 10min global brain ischemia. Apoptotic and necrotic cells were labelled and quantified in the affected hippocampus; exploratory activity, attention and memory functions were tested using open field, spontaneous alternation, novel object recognition and hole-board test. Age effect and treatment effect were analysed. High single dose (4mg/kg b.w.) of estradiol pre-treatment exposed a marked neuroprotective effect against hippocampal cell loss in all age groups. In behavioural tests, however, age-related differences could be observed. In middle-aged and old animals the worsening in memory function following ischemia was more prominent compared to that in the young ones. In the Y-maze and the novel object recognition tests the middle-aged, in the hole-board test (investigating working memory and total time) the old gerbils had the worst functional outcome. Only reference memory in hole-board test did not change by age. Estrogen improved memory performances in all the tests at every age. We can conclude that age of experimental animals is a factor worsening the outcome following brain ischemia. A single-dose estrogen therapy prevents the lesion-induced behavioural dysfunctions and the hippocampal cell loss.

Bcl-2 or bcl-XL gene therapy increases neural plasticity proteins nestin and c-fos expression in PC12 cells.

The anti-apoptotic gene replacements could be an option in preventing hypoxia-induced neuronal loss. In this paper we tested the effect of anti-apoptosis (bcl-2 and bcl-XL) gene transfer on cell plasticity. Nestin, synapsin-1 and c-fos genes and proteins expression were measured in PC12 cells in normal condition, and after hypoxia/re-oxygenation. Gene delivery results a significant increase in both bcl-2 and bcl-XL gene expression. Hypoxia (1h)/re-oxygenation (24h) have a detrimental effect upon cultured cells by increasing the pro-apoptotic, bax gene and protein expression. Bcl-2 or bcl-XL gene delivery resulted in a significant increase in and the cellular levels of the corresponding mRNAs and proteins. Bcl-2 gene augmented the nestin gene and protein expression which has been compromised previously by the hypoxic event. Similarly c-fos mRNA and protein expression decreased significantly after hypoxia, while the anti-apoptotic gene treatment normalized c-fos expression. Synapsin-1 gene or protein expression remained about on the same level under normoxic conditions or following hypoxia after gene treatment. We can conclude that anti-apoptotic gene transfers activate neuronal plasticity proteins nestin and c-fos. This link on anti-apoptotic proteins and cell plasticity is a new finding.

Adopted cognitive tests for gerbils: validation by studying ageing and ischemia.

Transient occlusion of common carotid arteries in gerbils is a simple and widely used model for assessing histological and functional consequences of transient forebrain ischemia and neuroprotective action of pharmaceuticals. In the present study we aimed to introduce additional behavioural tests as novel object recognition and food-motivated hole-board learning in order to measure attention and learning capacity in gerbils. For validating these cognitive tests the effects of ageing (4, 9 and 18 months) and those of transient forebrain ischemia induced by bilateral carotid occlusion at 9 months of age were investigated. Neuronal cell death was estimated in the hippocampus using TUNEL and caspase-3 double fluorescence labelling and confocal microscopy. Ageing within the selected range although influenced ambulatory activity, did not considerably change attention and memory functions of gerbils. As a result of transient ischemia a selective neuronal damage in CA1 and CA2 regions of the hippocampus has been observed and tested 4 days after the insult. Ischemic gerbils became hyperactive, but showed decreased attention and impaired spatial memory functions as compared to sham-operated controls. According to our results the novel object recognition paradigm and the hole-board spatial learning test could reliably be added to the battery of conventional behavioural tests applied previously in this species. The novel tests can be performed within a wide interval of adult age and provide useful additional methods for assessing ischemia-induced cognitive impairment in gerbils.

Modulation of fibrinolysis by the combined action of phospholipids and immunoglobulins.

Because both immunoglobulin G (IgG) and phospholipids interfere with fibrinolysis, their combined modulating effects were investigated in experimental models of three consecutive steps of the fibrinolytic process [diffusion of tissue-type plasminogen activator (tPA) into the clot, plasminogen activation on fibrin surface and fibrin dissolution by plasmin] using IgGs isolated from healthy subjects and from patients with antiphospholipid syndrome in combination with mixtures of synthetic dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylserine. In fibrin clots containing phospholipids the normal IgG enhanced the barrier function of the phospholipids with respect to the diffusion of tPA and plasminogen activation, but did not modify the lysis by plasmin. One of the examined antiphospholipid syndrome-IgGs also restricted the diffusion of tPA, but it accelerated the plasminogen activation on the fibrin surface and slowed down the lysis of fibrin by plasmin. Another antiphospholipid syndrome IgG, which did not affect significantly the tPA penetration into the fibrin gel, did not modify the plasminogen activation on its own, but it partially opposed the inhibiting effect of phospholipids on plasmin formation and accelerated the end-stage lysis of fibrin containing phospholipids. The IgGs from the two examined antiphospholipid syndrome patients did not show consistent deviation from the pattern of normal IgG effects on fibrinolysis in phospholipid environment. Thus, a high degree of heterogeneity with respect to the profibrinolytic or antifibrinolytic effects of the pathological IgGs can be expected in the antiphospholipid syndrome patient population, which may contribute to the variable thrombotic symptoms in this clinical syndrome.

Factor V Leiden and apolipoprotein E genotypes in severe femoropopliteal atherosclerosis with restenosis.

BACKGROUND: The role of factor V (Leiden) mutation, thrombophilia, and apolipoprotein E (apoE) alleles in the pathogenesis of accelerated atherosclerosis and restenosis was studied in patients requiring reoperation within five years after femoropopliteal angioplasty with artificial grafts. METHODS: One hundred ninety-eight consecutive patients with femoropopliteal atherosclerotic disease, reoperated for restenosis were contacted by phone and 100 of them returned for laboratory and clinical work-up. In addition to clinical evaluation and routine laboratory investigations, parameters of lipoprotein metabolism, factor V (Leiden) mutation and apolipoprotein E (apoE) allele were studied by PCR amplification of DNA and endonuclease digestion techniques. RESULTS: A significantly higher incidence of factor V (Leiden) mutation was found in patients with atherosclerosis and restenosis, compared to 445 healthy blood donors (13/200, 6.5% vs. 34/890, 3.8%, p=0.0379). Distribution of the alleles of the apolipoprotein E (apoE) gene was different, when the patients were compared to 372 controls; however, the difference only approached the level of statistical significance (25/200, 12.5% vs. 56/744, 7.5%, p=0.0515). Comparing the two groups, the number of epsilon4 allele carriers was significantly higher among patients with restenosis (25/100, 25% vs. 53/272, 14%, p=0.0147). CONCLUSION: Factor V (Leiden) mutation may influence the progression of atherosclerosis and the development of restenosis after revascularization in patients with accelerated femoropopliteal atherosclerosis. Further investigation is needed whether long-term anticoagulation has an impact or not on the course of disease in such cases. ApoE epsilon4 allele should be screened in patients with femoropopliteal atherosclerosis, because it indicates a faster progression of atherosclerosis and may predict restenosis after revascularization procedure.

Impaired inactivation by antithrombin and hirudin and preserved fibrinogen-clotting activity of thrombin in complex with anti-thrombin antibody from a patient with antiphospholipid syndrome.

Immunoglobulin G (IgG) isolated from the blood plasma of a patient with secondary antiphospholipid syndrome (APS) expresses fibrinogen-clotting and amidolytic activity (the thrombin activity in 20 micromole IgG is equivalent to approximately 5 nmole pure thrombin), and activates factor XIII. Hirudin (1 microM) decreases the intrinsic thrombin activity of the APS IgG by only 25%, whereas it inhibits completely pure thrombin with equivalent activity. Under conditions, when antithrombin inactivates 60% of the thrombin activity in the presence of normal IgG, the APS IgG protects almost completely the added thrombin against inactivation by antithrombin. Heparin, however, partially relieves this protective effect and at the same time it facilitates the inhibition of the intrinsic thrombin activity by antithrombin. The APS IgG reduces the thrombin activity in protein C activation assay by 50% compared to the activity in the presence of normal IgG. All described properties are related to the Fab fragment of the antibody. The IgG preserving the fibrin-generating activity of thrombin with concomitant protection against inhibitors unravels a new aspect of the thrombotic mechanism in APS. This condition is probably rare: only one out of 23 examined patients with primary or secondary APS expresses IgG with the described properties.

Human cerebral microvessel endothelial cell culture as a model system to study the blood-brain interface in ischemic/hypoxic conditions.

(1) Cerebral ischemia and reperfusion induce several changes on the endothelial cells at the microcirculatory level. (2) Vasogenic brain edema due to compromised blood-brain barrier, transformation of the endothelial cell surface from an anticoagulant to a procoagulant surface are important factors in the pathogenesis of ischemic stroke. (3) Release of prostaglandins, endothelin-1, complement proteins, and matrix metalloproteinase-9 by microvascular endothelial cells are other components in the complex mechanism of brain ischemia/hypoxia. (4) Ultrastructural studies documented the opened paracellular avenues in the course of vasogenic edema in different experimental models (5) Tight junctions of endothelial cells have been characterized with freeze fracture electron microscopy, and the process of transvesiculation was analyzed using rapid freeze and freeze substitution procedure before electron microscopy studies (6) In endothelial cell-culture experiments, we used rodent and later human brains. (7) Endothelial cells co-cultured with astroglia resulted in an elaborate tight junctional complex. (8) This co-culture technique becomes the basis of in vitro blood-brain barrier studies On endothelial cells of human brain origin, different regulatory factors found to be responsible for the complex mechanism of ischemic stroke.

[Heparin inhibits metastatization of experimental melanoma]. / Heparinkezelés hatása a melanoma áttétképzésére preklinikai modellben.

Heparin treatment, at human equivalent doses, modulates coagulation parameters in mice similarly to the human situation. Heparins were tested in various melanoma metastasis models for their antimetastatic activity. Heparins were active against melanoma metastasis without influencing the primary tumor. Tumor cell-induced platelet aggregation was not the primary target of heparins, since melanoma cells were not active in this respect. Our results support the notion that heparins have antimetastatic activity.

Matrix metalloproteinase-9 expression in post-hypoxic human brain capillary endothelial cells: H2O2 as a trigger and NF-kappaB as a signal transducer.

The haemorrhagic transformation in ischemic stroke involves disruption of the integrity of the microvascular beds, partially based on the action of matrix metalloproteinases (MMPs). The objective of the present study was to evaluate the contribution of microvascular endothelial cells from human brain (HBECs) to MMPs' expression and regulation under conditions relevant to brain ischemia. MMPs and their inhibitors were examined with zymography, Western-blotting, ELISA and MMP-activity assay in cultured HBECs. Four-hour hypoxia (pO(2)=60 mmHg) elevated the level of MMP-9 in the supernatant of the HBECs and this early response required collagen-matrix. Active oxygen species sustained the increased MMP-9 activity for at least 24 h. In the post-hypoxic period 20 micro mol/L H(2)O(2) caused a 6-fold increase in the specific activity of MMP-9 over the normoxic cells and a comparable effect was exerted by thrombin (50 nmol/L) and leukocyte elastase (10 nmol/L). The role of NF-kappaB, a redox-state sensitive transcription factor, was evaluated with immunofluorescence confocal microscopy and immunoblotting of nuclear and cytoplasmic extracts. The oxidative stress-dependent MMP-9 induction was accompanied by a significant increase in the NF-kappaB localized in the nuclei and these responses were blunted with a proteasome inhibitor (MG132). Consequently, according to our in vitro data HBECs are a source of MMP-9, which is under the control of triggers relevant to the ischemic/reperfused brain (reactive oxygen species, thrombus and inflammation related proteases) and this regulation is partially based on NF-kappaB activation. The reported regulation of endothelium-derived MMP-9 supports its potential involvement in the post-hypoxic disturbances of the cerebral microcirculation.

[Thrombolytic therapy in acute ischemic stroke with streptokinase]. / Akut ischaemiás stroke thrombolyticus kezelése sztreptokinázzal.

AIM AND METHODS: In an open, observational study, 40 consecutive ischemic stroke patients eligible for thrombolytic therapy using the combined ECASS/NINDS inclusion criteria have been treated intravenously with 1.5 M units of streptokinase. The therapeutic window was 3 hours or shorter. RESULTS: The safety analysis documented a low rate (5%) of intracerebral hemorrhages, and an additional 13% rate of hemorrhagic transformation of the initial infarction. Two patients died due to intracerebral bleeding. The efficacy of the SK thrombolysis was significant in 53% of the patients (the mean of the improvement on the NIH stroke scale was 15 points), while an other 42% of the patients achieved only the mean of 4 points improvement on their NIHSS score. DISCUSSION: These results are of the same magnitude, as those documented in the NINDS trial with rt-PA. Time window rather than the thrombolytic agent itself seems to be the decisive factor for successful thrombolysis. CONCLUSION: The good safety profile of SK in acute stroke using the ECASS/NINDS criteria, and the cost-effectiveness of the drug underline the necessity of a new SK trial with the recently accepted inclusion and exclusion criteria.