HMG CoA reductase inhibitors affect the fibrinolytic system of human vascular cells in vitro: a comparative study using different statins

1. The results of several clinical studies investigating the effect of statin therapy on the fibrinolytic system in vivo are inconclusive. We compared the effect of six different statins (atorvastatin, cerivastatin, fluvastatin, lovastatin, pravastatin, simvastatin) on components of the fibrinolytic system expressed by human vascular endothelial cells and smooth muscle cells and by the human hepatoma cell line HepG2. 2. All statins used except pravastatin significantly decreased PAI-1 production in human endothelial and smooth muscle cells. This effect was also seen in the presence of IL-1 alpha and TNF-alpha. All statins except pravastatin increased t-PA production in human smooth muscle cells. On a molar basis cerivastatin was the most effective HMG CoA reductase inhibitor used. Only simvastatin and lovastatin increased t-PA production in endothelial cells. The effects on the fibrinolytic system were reversed by mevalonate. Statins decreased mRNA levels for PAI-1 in endothelial and smooth muscle cells and increased mRNA levels for t-PA in smooth muscle cells. Statins did not affect PAI-1 expression in HepG2 cells. Cell viability was not influenced by statins in endothelial cells and HepG2 cells whereas in smooth muscle cells a cytotoxic effect was seen at high concentrations. 3. If the effects on the fibrinolytic system of vascular cells in vitro shown in this study are also operative in vivo one could speculate that by increasing t-PA and decreasing PAI-1 at sites of vascular lesions statins might reduce fibrin formation and thrombus development. Such an effect might contribute to the clinically proven benefits of statin therapy.     

In vivo and in vitro labelling of perineuronal nets in rat brain

Previous lectin-histochemical and immunocytochemical investigations using fixed tissue revealed perineuronal nets as lattice-like accumulations of extracellular matrix proteoglycans at the surface of several types of neurons. In the present study, perineuronal nets in the rat brain were labelled for the first time in vivo by stereotaxic injections of biotinylated Wisteria floribunda agglutinin (Bio-WFA), as well as in vitro, by incubation of unfixed brain slices with the same lectin. Six days after Bio-WFA injections into the parietal cortex, medial septum, reticular thalamic nucleus and red nucleus, the lectin remaining bound to perineuronal nets was detected by streptavidin/biotinylated peroxidase complexes or red fluorescent Cy3-streptavidin, respectively. Double-fluorescence labelling showed that Bio-WFA applied in vivo reacted with the chondroitin sulphate proteoglycan immunoreactive perineuronal nets in the injection zone. Labelling of perineuronal nets in unfixed slices was obtained with either Cy3-tagged WFA or Bio-WFA and subsequent visualization by Cy3-streptavidin which confirmed the region-dependent distribution patterns and the structural characteristics of perineuronal nets known from histochemical studies. These results provide support for the role of extracellular matrix proteoglycans to maintain a considerable chemical and, probably, spatial heterogeneity of the extracellular space in vivo. The ability of in vivo and in vitro labelling may promote the functional characterization of the extracellular matrix in various brain structures including its species-dependent neuronal association patterns.     

Biologische Untersuchungen an Ascaridia galli Schrank 1788

Ohne ZusammenfassungMit 10 Textabbildungen.     

Periventrikuläre fettige Metamorphose der Neuroglia — Ein morphologisches Substrat beim SIDS

Zusammenfassung Im Rahmen histologischer Untersuchungen wurde in 7 von 15 Fällen von SIDS eine massive fettige Metamorphose der Gliazellen des periventrikulären frontalen Marklagers vorgefunden. Eine Kontrollgruppe von 6 Kleinkindern (Alter unter 1 Jahr), die infolge eines anderen natürlichen oder gewaltsamen Todes gestorben waren, wies in keinem Fall diese morphologischen Veränderungen auf. Dünnschichtchromatographische Analysen der beim SIDS in den Gliazellen gespeicherten Lipide ergab einen hohen Anteil von Cholesterinestern, während jener in der Kontrollgruppe stets nieder war. Die fettige Gliametamorphose wird als morphologisches Substrat einer geringgradigen Schädigung unterschiedlicher Ätiologie der metabolisch besonders aktiven, noch unreifen Gliazellen der periventrikulären Marksubstanz in Erwägung gezogen.     

Leucocytapheresis with Adacolumn enhances HCV-specific proliferative responses in patients infected with hepatitis C virus genotype 1

The most important aim in controlling virus infections is to destroy infected cells. Impaired cellular immunity in HIV and HCV infection leads to chronic infection. This study examined the effect of cytapheresis on the subsequent response to interferon/ribavirin treatment in patients infected with HCV. Adacolumn cytapheresis was carried out once a day for 5 consecutive days in patients who relapsed or did not respond to previous peginterferon and ribavirin combination treatment (n = 14: relapsers = 3, non-responders = 11). Peginterferon and ribavirin combination treatment was started after cytapheresis. During combination treatment, the proliferative response of peripheral blood mononuclear cells to HCV proteins (core, NS3, NS4, and NS5), tetanus toxoid, and phytohemagglutinin was measured, and compared to the early virological response. After treatment by leucocytapheresis, the proliferative response of peripheral blood mononuclear cells to HCV-core and tetanus toxoid increased significantly over the baseline (P < 0.05). A marked increase in the phytohemagglutinin response was observed after peginterferon and ribavirin combination treatment was started (P < 0.01 at week 5 and P < 0.005 at week 13). There were, however, no clear changes in the proliferative response to other antigens. Among the 14 patients, 12 (85.7%) achieved an early virological response by week 13 (12 weeks after the start of combination treatment). After treatment, nine patients (64.3%) had a significant proliferative response to HCV core antigen. Among the nine patients, eight patients (88.9%) achieved early virological response. The results indicate that activation of cellular immunity by leucocytapheresis facilitates an early virological response rate in HCV patients. This new therapy may, therefore, become an additional therapeutic measure for HCV.     

Development and validation of a whole-cell inhibition assay for bacterial methionine aminopeptidase by surface-enhanced laser desorption ionization-time of flight mass spectrometry

Bacterial methionine aminopeptidase (MAP) is a protease that removes methionine from the N termini of newly synthesized bacterial proteins after the peptide deformylase enzyme cleaves the formyl group from the initiator formylmethionine. MAP is an essential bacterial gene product and thus represents a potential target for therapeutic intervention. A fundamental challenge in the antibacterial drug discovery field is demonstrating conclusively that compounds with in vitro enzyme inhibition activity produce the desired antibacterial effect by interfering with the same target in whole bacterial cells. One way to address the activity of inhibitor compounds is by profiling cellular biomarkers in whole bacterial cells using compounds that are known inhibitors of a particular target. However, in the case of MAP, no specific inhibitors were available for such studies. Instead, a genetically attenuated MAP strain was generated in which MAP expression was placed under the control of an inducible arabinose promoter. Thus, MAP inhibition in whole cells could be mimicked by growth in the absence of arabinose. This genetically attenuated strain was used as a benchmark for MAP inhibition by profiling whole-cell lysates for unprocessed proteins using surface-enhanced laser desorption ionization-time of flight mass spectrometry (MS). Eight proteins between 4 and 14 kDa were confirmed as being unprocessed and containing the initiator methionine by adding back purified MAP to the preparations prior to MS analysis. Upon establishing these unprocessed proteins as biomarkers for MAP inhibition, the assay was used to screen small-molecule chemical inhibitors of purified MAP for whole-cell activity. Fifteen compound classes yielded three classes of compound with whole-cell activity for further optimization by chemical expansion. This report presents the development, validation, and implementation of a whole-cell inhibition assay for MAP.     

Prophylactic treatment of known ifosfamide-induced encephalopathy for chemotherapy with high-dose ifosfamide?

We report about a case of advanced Ewing sarcoma in a 30-year-old woman. Initial treatment was started according to the Euro-Ewing 99 protocol. During the initial therapy, an ifosfamide-induced encephalopathy occurred as status epilepticus. Because of cerebral toxicity, the following chemotherapies went without ifosfamide. During final radiotherapy multiple lung metastasis were diagnosed. After two cycles of chemotherapy with cyclophosphamide and topotecan (no response), left thoracotomy, and palliative pneumectomy, the patient was transferred to our ward for further treatment. Undergoing two cycles of chemotherapy with ifosfamide 4 g/m² intravenously for 3 consecutive days followed by high-dose chemotherapy (HDCT) according to the ICE-regimen (ifosfamide 2 g/m², carboplatin 200 mg/m², and etoposide 2×100 mg/m² intravenously for 6 consecutive days), and peripheral blood stem cell transplantation (PBSCT), complete remission was achieved. Under preventive therapy with methylene blue, thiamin, and glucose 5% infusions, no encephalopathy occurred.     

Detection of chronic sensorimotor impairments in the ladder rung walking task in rats with endothelin-1-induced mild focal ischemia

A comprehensive evaluation of the effects of neuroprotection, neurogenesis, and compensatory mechanisms on the outcome of ischemic insults requires assessment of morphological and functional parameters. Behavioural tests are essential when recording performance throughout the time course of an experiment and the results bear predictive value in preclinical animal models. The goal of this study was to establish a behavioural test procedure for a model of transient focal ischemia induced by injection of endothelin-1 (eMCAO) that results in relatively mild behavioural deficits. The test protocol used in the present study allows evaluation of quantitative and qualitative impairments in skilled motor performance and is sensitive to detect chronic deficits at chronic post-ischemic time intervals. The ladder rung walking task [J. Neurosci. Methods 115 (2002) 169] is a motor test that assesses skilled walking and measures both forelimb and hindlimb placing, stepping and inter-limb co-ordination. In this study we tested the effect of two different technical variants of endothelin-1 application on infarct volume and motor skills (1) application via pre-implanted guiding cannula in awake animals and (2) via direct injection under halothane anaesthesia. We showed that the ladder rung walking task is sensitive in the assessment of loss of fine motor function after induction of relatively small lesions. In animals with implanted cannulas we found a smaller infarct area and an increase in placement errors prior to ischemia animals with eMCAO under anaesthesia showed a long lasting impairment of the contralateral forelimb up to 4 weeks post-eMCAO.     

Effects of a xanthine derivative, propentofylline, on local cerebral blood flow and glucose utilization in the rat

The effects of the xanthine derivative propentofylline [3-methyl-1-(5′-oxohexyl)-7-propylxanthinel were measured on local cerebral blood flow and glucose utilization in the rat using quantitative autoradiographic techniques. A dose of 0.5 mg/kg/min i.v. produced increases in local cerebral blood flow and minimal effects on glucose utilization in the majority of cerebral structures measured. A higher dose of propentofylline (1.5 mg/kg/min) produced an overall increase in local cerebral blood flow and a marked reduction in glucose utilization. Furthermore, propentofylline increased the average ratio of blood flow per unit glucose utilization and thus is capable of increasing cerebral blood flow in excess of metabolic demand. While the mechanism of action of this compound has not been fully defined. it is possible that its cerebrovascular and cerebral metabolic effects can at least partially be explained by a blockade of adenosine uptake. These actions of propentofylline on cerebral blood flow and metabolism may play a role in protecting neuronal tissue under hypoxic/ischemic conditions in the brain.