High-dose propranolol attenuates pressor responses to norepinephrine in mesenteric arterial beds of rats

Propranolol is used for medical treatment of portal hypertension as it is believed to act as an indirect splanchnic vasoconstrictor via blockade of vasodilatory ₂-receptors. However, a high proportion of nonresponders have been demonstrated in hemodynamic studies of the portal hypotensive effect of propranolol. The aim of the present study was to investigate the effect of various concentrations of propranolol on norepinephrine-induced pressor responses in isolated perfused mesenteric arteries of rats. Mesenteric arterial beds of six rats were perfused at a constant rate of 2 ml/minute with Krebs-Ringer solution at 37°C, and perfusion pressure was continuously recorded. Pressor responses to bolus injections of norepinephrine tended to increase in the presence of 10^–6 M propranolol but were significantly attenuated in the presence of 10^–5 M propranolol. In conclusion, a high concentration of propranolol paradoxically attenuates the pressor responses to norepinephrine in mesenteric arterial beds of rats. This is most likely explained by a nonspecific local anesthetic effect of propranolol.Presented at The 35th World Congress, International College of Angiology, Copenhagen, Denmark, July 1993     

Bendamustine in patients with relapsed or refractory multiple myeloma

Objective

In patients with multiple myeloma, bendamustine monotherapy is effective as 1^st and 2^nd line therapy. However, data for patients with advanced multiple myeloma is rare.

Methods

In this retrospective analysis we have identified 39 patients with relapsed or refractory multiple myeloma by means of case research, who have been treated at our institution with bendamustine as salvage therapy. After in median 2 lines of prior therapy (range:1-5) patients received in median 3 (range: 1-10) cycles of bendamustine. Bendamustine dosage was 80-150 mg on day 1+2 of a monthly cycle. Bendamustine was administered as monotherapy in 39% of patients, whereas 61% received concomitant steroids.

Results

Toxicity was mild to moderate. Response rates were as follows: 3% vgPR, 33% PR, 18% MR, 26% SD and 20% PD. The median event-free and overall survival were 7 and 17 months, respectively.

Conclusions

In conclusion, in patients with advanced multiple myeloma bendamustine is effective and associated with mild toxicity. Therefore, the role of bendamustine in patients with multiple myeloma should be investigated in further clinical trials.     

Discrepant results between pyrazinamide susceptibility testing by the reference BACTEC 460TB method and pncA DNA sequencing in patients infected with multidrug-resistant W-Beijing Mycobacterium tuberculosis strains

BACKGROUND: Mycobacterium tuberculosis strains belonging to the W-Beijing family have received broad clinical and public health attention because of their rapid worldwide spread and their frequent association with outbreaks, multidrug resistance, and treatment failures and relapses. METHODS: The present study examined a large number of multidrug-resistant strain-W isolates (isolates of 29 patients) by susceptibility testing for pyrazinamide (PZA) using the reference BACTEC 460TB method (Becton Dickinson Diagnostic Instrument Systems; Sparks, MD) and also by DNA sequencing of the pncA gene. RESULTS: We found that despite of the presence of a strain W-specific Thr47Ala in the pncA gene, all strains showed susceptibility to PZA in the reference BACTEC 460TB system due to their higher minimum inhibitory concentrations (relative to BACTEC 460TB PZA-susceptible strains). CONCLUSIONS: Our results suggest that the current radiometric reference method cannot reproducibly detect PZA resistance in patients infected with W-Beijing strains. Therefore, PZA susceptibility testing should instead be based on analysis of the pncA gene for resistance-associated mutations.     

Epidemiology of SHV-type beta-lactamase-producing Klebsiella spp. from outbreaks in five geographically distant Hungarian neonatal intensive care units: widespread dissemination of epidemic R-plasmids

One hundred and twenty-six extended-spectrum β-lactamase-producing clinical isolates of Klebsiella spp. were collected in 1998, 2002 and 2003 from seven outbreaks in neonatal intensive care units (NICUs) of five Hungarian county and teaching hospitals. The isolates were multidrug resistant but were susceptible to ciprofloxacin. Pulsed-field gel electrophoresis revealed the existence of 12 distinct genetic clones, 10 of which proved epidemic in the studied NICUs. All isolates harboured plasmids ranging from 2.3 kb to 228 kb, representing 12 diverse plasmid profiles. Sequence analysis of SHV-specific polymerase chain reaction products from 13 representative isolates detected the bla_SHV-2a gene in three and the bla_SHV-5 gene in seven epidemic clones, respectively. In the majority of isolates the bla_SHV genes were on transferable plasmids of 94 kb. EcoRI and PstI digestion of plasmid DNA from transconjugants revealed identical or closely related restriction patterns in nine bla_SHV-5-harbouring R-plasmids and in two bla_SHV-2a-harbouring R-plasmids carried by strains obtained from geographically distant NICUs. Endemic clones in individual wards or epidemic clones affecting multiple healthcare facilities were not found. However, similarities observed in the size and restriction pattern of the plasmids hints at the multiple transfer of epidemic R-plasmids responsible for a sequence of outbreaks in Hungary.     

The multiple function of Grb2 associated binder (Gab) adaptor/scaffolding protein in immune cell signaling

The Grb2 associated binder (Gab) adaptor/scaffolding protein family comprises conserved proteins: mammalian Gab1, Gab2 and Gab3, Drosophila Dos and Caenorhabditis elegans Soc1. Gab adaptors are involved in multiple signaling pathways mediated by receptor- and non-receptor protein tyrosine kinases (PTKs), and become phosphorylated upon stimulation by growth factors-, cytokines-, Ig Fc- and antigen receptors. Through its phosphorylated tyrosine containing motifs, proline-rich sequences and pleckstrin homologue (PH) domain Gab adaptors may generate an interacting platform for proteins with SH2 and SH3 domains and may transfer these molecules to the plasma membrane, thereby contributing to their activation. This review will concentrate on the function of mammalian Gab proteins in the signal transduction triggered by immune receptors.     

Platelet activation and high tissue factor level predict acute stent thrombosis in pig coronary arteries: prothrombogenic response of drug-eluting or bare stent implantation within the first 24 hours

Increased thrombogenicity of drug-eluting stents (DESs) has recently been reported. The aim of the present study was to investigate the prothrombogenic effect of DESs and Bare stents, and determine factors predictive of acute stent thrombosis (AST) in preclinical experiments using new stent design or coating. Circulating pre- and post-stenting parameters of platelet activation (mean platelet volume, MPV; platelet distribution width, platelet large cell ratio), thrombin activation (thrombin-antithrombin complex, TAT and prothrombin fragments, F1+2), tissue factor antigen (TF-ag) and -activity (TF-act) and plasminogen activator inhibitor-1 (PAI-1) were measured in 141 consecutive pigs. Stent implantations were performed after pretreatment with aspirin and clopidogrel with unfractionated heparin anticoagulation. Nineteen pigs (groups AST-DES, n = 12; and AST-Bare, n = 7) died mean 6.3 +/- 2.9 h after stent implantation from AST. The remaining 122 control (C) pigs (groups C-DES, n = 76, and C-Bare, n = 46) survived the 1-month follow-up. Non-significantly elevated levels of post-stent F1+2 and TAT were measured in AST groups. Post-stenting MPV was increased significantly in the groups ASTDES and AST-Bare as compared with the groups C-DES and C-Bare (11.73 +/- 1.12 and 11.6 +/- 0.68 vs. 8.85 +/- 0.78 and 9.04 +/- 0.81 fL; p < 0.001), similarly to TF-ag (189.1 +/- 87.5 and 127 +/- 34.9 vs. 42.5 +/- 24.6 and 35.3 +/- 37.6 pg/ml; p < 0.001, respectively), Tfact (3.23 +/- 0.95 and 2.73 +/- 1.68 vs. 1.43 +/- 1.12 and 1.61 +/- 1.31 pM; p < 0.01, respectively) and PAI-1 (99.1 +/- 15.8 and 99 +/- 14.7 vs.53.4 +/- 40.2 and 46.9 +/- 42.4 ng/ml;p < 0.01, respectively). Multivariate analysis revealed elevated post-stenting plasma levels of TF-ag (p = 0.016) and MPV (p = 0.001) as independent risk factors for developing AST within the first 24 h in a porcine coronary stent model.     

Identification of novel neuropeptides in the ventral nerve cord ganglia and their targets in an annelid worm,Eisenia fetida

Periviscerokinins (PVKs) and pyrokinins (PKs) are neuropeptides known in several arthropod species. Sequence homology of these peptides with the molluscan small cardioactive peptides reveals that the occurrence of PVKs and PKs is not restricted to arthropods. Our study focuses on the biochemical and immunocytochemical identification of neuropeptides with sequence homology to PVKs and PKs in the central and peripheral nervous system of the earthworm Eisenia fetida. By means of affinity chromatography, nanoflow liquid chromatography, and high accuracy mass spectrometry, six peptides, SPFPR(L/I)amide, APFPR(L/I)amide, SPLPR(L/I)amide, SFVR(L/I)amide, AFVR(L/I)amide, and SPAFVR(L/I)amide, were identified in the central nervous system with the common ?XR(L/I)amide C‐terminal sequence. The exact anatomical position of 13 labeled XR(I/L)amide expressing neuron groups and numerous peptide‐containing fibers were determined by means of immunocytochemistry and confocal laser scanning microscopy in whole‐mount preparations of ventral nerve cord ganglia. The majority of the stained neurons were interneurons with processes joining the distinct fine‐fibered polysegmental tracts in the central neuropil. Some stained fibers were seen running in each segmental nerve that innervated metanephridia and body wall. Distinct groups of neurosecretory cells characterized by small round soma and short processes were also identified. Based on immunoelectron microscopy six different types of labeled cells were described showing morphological heterogeneity of earthworm peptides containing elements. Our findings confirm that the sequence of the identified earthworm neuropeptides homologous to the insect PVKs and PKs suggesting that these peptides are phylogenetically conservative molecules and are expressed in sister‐groups of animals such as annelids, mollusks, and insects. J. Comp. Neurol. 514:415–432, 2009. © 2009 Wiley‐Liss, Inc.     

Changes in the Expression of PACAP-like Compounds During the Embryonic Development of the Earthworm Eisenia fetida

Pituitary adenylate cyclase-activating polypeptide (PACAP) is expressed at very early stages in the vertebrate nervous system, and its functions in the embryonic development have been shown by various studies. PACAP is an extremely conserved molecule in phylogeny; however, little is known about its presence and functions in invertebrates. Our previous studies have shown the occurrence of PACAP-like immunoreactivity in the invertebrate nervous system. The aim of this study was to investigate the presence and localization of PACAP-like compounds during the embryonic development of earthworms from cocoon deposition to hatching using immunological methods (radioimmunoassay, dot blot, immunohistochemistry). PACAP-like immunoreactive compounds were detected at very early stages of the embryonic development of the earthworm Eisenia fetida. No significant changes were observed during the early stages in the developing embryo, but a marked increase occurred before hatching. In contrast, during the embryonic development, the level of PACAP-like compounds gradually decreased in cocoon fluids. Immunohistochemistry revealed the presence of PACAP-like immunoreactive cell bodies and processes in the developing body wall, prostomium, pharyngeal wall, and central nervous system. Cells located in the body wall correspond to putative progenitor cells of primary sensory cells. In the present study, we also showed that the clitellum (reproductive organ) of sexually mature worms contained significantly higher levels of PACAP-like immunoreactivity than other regions of the same animals or the clitellar region of a non-reproducing animal. In summary, these observations provide a morphological basis and suggest a role of PACAP(-like peptides) in the reproductive and developmental functions of invertebrates.     

Differences between normal and alpha-synuclein overexpressing SH-SY5Y neuroblastoma cells after Abeta(1-42) and NAC treatment

Alpha-synuclein (alphaSN) plays a major role in numerous neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. Intracellular inclusions containing aggregated alphaSN have been reported in Alzheimer's and Parkinson's affected brains. Moreover, a proteolytic fragment of alphaSN, the so-called non-amyloid component of Alzheimer's disease amyloid (NAC) was found to be an integral part of Alzheimer's dementia related plaques. Despite the extensive research on this topic, the exact toxic mechanism of alphaSN remains elusive. We have taken the advantage of an alphaSN overexpressing SH-SY5Y cell line and investigated the effects of classical apoptotic factors (e.g. H(2)O(2), amphotericin B and ruthenium red) and aggregated disease-related peptides on cell viability compared to wild type neuroblastoma cells. It was found that alphaSN overexpressing cells are more sensitive to aggregated peptides treatment than normal expressing counterparts. In contrast, cells containing elevated amount of alphaSN were less vulnerable to classical apoptotic stressors than wild type cells. In addition, alphaSN overexpression is accompanied by altered phenotype, attenuated proliferation kinetics, increased neurite arborisation and decreased cell motility. Based on these results, the alphaSN overexpressing cell lines may represent a good and effective in vitro model for Alzheimer's and Parkinson's disease.     

Cyclooxygenase inhibition in human monocytes increases endotoxin-induced TNF alpha without affecting cyclooxygenase-2 expression

Human endotoxin-stimulated adherent monocytes were used in order to determine whether or not NSAIDs influence cyclooxygenase-2 and/or tumor necrosis factor (TNF)alpha expression within the range of inhibitor concentrations that are required to suppress prostaglandin biosynthesis. Exogenous prostaglandin E(2) (IC(50)<5 nM) inhibited endotoxin-induced TNFalpha mRNA and protein while, up to 1 microM, it did not significantly affect cyclooxygenase-2 mRNA expression. Similar results were obtained using the membrane-permeable cAMP analogue db-cAMP, which caused preferential inhibition of TNFalpha expression. Indomethacin or lysine-acetylsalicylic acid concentration-dependently inhibited prostaglandin E(2) biosynthesis and, at concentrations causing near-complete inhibition, enhanced TNFalpha mRNA and protein expression without significantly influencing cyclooxygenase-2 mRNA. In addition, by facilitating endotoxin-induced TNFalpha expression, indomethacin or lysine-acetylsalicylic acid counteracted dexamethasone-induced inhibition of TNFalpha biosynthesis, thereby exhibiting an effect opposite to that of exogenous prostaglandin E(2). The results suggest that in human endotoxin-stimulated monocytes, NSAIDs can enhance TNFalpha expression through inhibition of cyclooxygenase and the resulting decrease in prostanoid biosynthesis.