Does permanent carotid artery occlusion produce a 'preconditioning-like' effect towards more severe hypotension in energy metabolites? Role of cerebral adenosine

1. The aim of the present study was to investigate the potential energy preserving effect of permanent bilateral common carotid artery occlusion (BCCAO) towards additional systemic hypotension of severe duration (30 min). In addition, the role of adenosine A1 receptors in cerebral ischaemic preconditioning was investigated in male Wistar rats. Thus, oligaemic rats were assigned randomly to continuous treatment with the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA) or the adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT), receiving daily intraperitoneal infusions of 0.1 mg/kg bodyweight CCPA or CPT or placebo (200 microL aqueous 2-hydropropyl-beta-cyclodextrin) at a delivery rate of 0.5 microL/h over 14 days. 2. Haemodynamic parameters and arterial blood gases were monitored. Rat cortical energy metabolites ATP, ADP, AMP, phosphocreatine and adenosine were measured using HPLC techniques. Adenosine A1 receptor expression was determined by immunhistochemistry and quantified by western blotting. 3. Two weeks of permanent BCCAO induced an 'energy saving' effect in rat cortical ATP concentrations. Under subchronic conditions, significant increases were detected in ADP and AMP concentrations after CCPA compared with placebo. Because similar changes were also seen after CPT, this adenosine A1 receptor-mediated effect does not seems to be specific. Furthermore, no differences in adenosine A1 receptor expression could be detected. 4. Adenosine was not specifically involved in the 'preconditioning-like' effect via the modulation of the adenosine A1 receptor in the present oligaemia model. Obviously, adenosine A1 receptor-specific effects after delayed cerebral ischaemic preconditioning do not seem to play an essential role if BCCAO is followed by a prolonged additional severe ischaemic event.     

Development of tetravalent, bispecific CCR5 antibodies with antiviral activity against CCR5 monoclonal antibody-resistant HIV-1 strains

In this study, we describe novel tetravalent, bispecific antibody derivatives that bind two different epitopes on the HIV coreceptor CCR5. The basic protein formats that we applied were derived from Morrison-type bispecific antibodies: whole IgGs to which we connected single-chain antibodies (scFvs) via (Gly4Ser)n sequences at either the C or N terminus of the light chain or heavy chain. By design optimization, including disulfide stabilization of scFvs or introduction of 30-amino-acid linkers, stable molecules could be obtained in amounts that were within the same range as or no less than 4-fold lower than those observed with monoclonal antibodies in transient expression assays. In contrast to monospecific CCR5 antibodies, bispecific antibody derivatives block two alternative docking sites of CCR5-tropic HIV strains on the CCR5 coreceptor. Consequently, these molecules showed 18- to 57-fold increased antiviral activities compared to the parent antibodies. Most importantly, one prototypic tetravalent CCR5 antibody had antiviral activity against virus strains resistant to the single parental antibodies. In summary, physical linkage of two CCR5 antibodies targeting different epitopes on the HIV coreceptor CCR5 resulted in tetravalent, bispecific antibodies with enhanced antiviral potency against wild-type and CCR5 antibody-resistant HIV-1 strains.     

Three microsatellites from the T1DGC MHC data set show highly significant association with type 1 diabetes, independent of the HLA-DRB1, -DQA1 and -DQB1 genes

Aim:  The aim of this study was to test the microsatellites in the Type 1 Diabetes Genetics Consortium major histocompatibility complex (MHC) data set for association with type 1 diabetes (T1D) independent of the HLA-DRB1 , -DQA1 and -DQB1 genes.
Methods:  The data set was edited to contain only one affected child per family, and broad ethnic subgroups were defined. Genotypes for HLA-DRB1 , -DQA1 and -DQB1 were replaced by a haplotype code spanning all three loci, with phase inferred based on common haplotypes. The final data set contained 8190 samples in 2301 families, 59 microsatellites and the DRB1–DQA1–DQB1 haplotype code. Statistical analyses consisted of conditional logistic regression and haplotype estimations and linkage disequilibrium calculations.
Results:  The data set was screened using a main effects test approach adjusted for DRB1–DQA1–DQB1 , and significant results tested for validity. After these procedures, four markers remained significant at the Bonferroni-corrected threshold: D6S2773 (p = 0.00014), DG6S185 (p = 0.00015), DG6S398 (p = 0.00043) and D6S2998 (p = 0.00015). These results were supported by allelic tests conditioned on DRB1–DQA1–DQB1 haplotypes, except for DG6S185 , which may contain artefacts.
Conclusions:  We have identified three microsatellites that mark additional risk factors for T1D at highly significant levels in the MHC. Further analyses are needed to establish the relationship with other possible genetic determinants in this region.     

3D MR coronary angiography: optimization of the technique and preliminary results

Objective: Current clinical full MR angiography with multiple breathhold multiple thin slab acquisition (MTS) is difficult and arduous. This study describes the optimisation of the whole heart free – breathing balanced turbo field echo (B-TFE) protocol. A high-resolution image of the whole heart is produced in less or comparable time to MTS acquisition and allows for reconstruction afterwards to visualise the individual coronary arteries. The scan is easily performed because the volume has to be targeted only once.Design and setting: Eighteen healthy adults without a history of cardiovascular disease underwent free-breathing 3D MR angiography with the B-TFE protocol. The whole-heart data set was reformatted in identical orientations in all subjects to visualise the major coronary arteries.Main outcome measures: Vessel length, signal and contrast to noise ratio were determined and compared for each vessel.Results: Mean visible vessel lengths were 116 mm for the right, 102 mm for the left main and left descending and 76 mm for the left circumflex coronary artery. The average signal to noise ratio was 7.5 and contrast to noise ratio was 4.9. Because of the need for synchronised cardiac and respiratory triggering the coronaries could not be judged in 25% of the subjects.Conclusions: The optimised B-TFE protocol had equal judgeability and vessels could be judged over longer contiguous distances compared to earlier implementations of the B-TFE protocol. We conclude whole heart free breathing navigator-gated and slice-tracked 3D coronary MR angiography with use of the adjusted B-TFE protocol is possible, but still suboptimal for clinical use.     

European cardiovascular magnetic resonance (EuroCMR) registry – multi national results from 57 centers in 15 countries

Abstract

Background

The EuroCMR registry sought to evaluate indications, image quality, safety and impact on patient management of clinical routine CMR in a multi-national European setting. Furthermore, interim analysis of the specific protocols should underscore the prognostic potential of CMR.

Methods

Multi-center registry with consecutive enrolment of patients in 57 centers in 15 countries. More than 27000 consecutive patients were enrolled.

Results

The most important indications were risk stratification in suspected CAD/Ischemia (34.2%), workup of myocarditis/cardiomyopathies (32.2%), as well as assessment of viability (14.6%). Image quality was diagnostic in more than 98% of cases. Severe complications occurred in 0.026%, always associated with stress testing. No patient died during or due to CMR. In 61.8% CMR findings impacted on patient management. Importantly, in nearly 8.7% the final diagnosis based on CMR was different to the diagnosis before CMR, leading to a complete change in management. Interim analysis of suspected CAD and risk stratification in HCM specific protocols revealed a low rate of adverse events for suspected CAD patients with normal stress CMR (1.0% per year), and for HCM patients without LGE (2.7% per year).

Conclusion

The most important indications in Europe are risk stratification in suspected CAD/Ischemia, work-up of myocarditis and cardiomyopathies, as well as assessment of viability. CMR imaging is a safe procedure, has diagnostic image quality in more than 98% of cases, and its results have strong impact on patient management. Interim analyses of the specific protocols underscore the prognostic value of clinical routine CMR in CAD and HCM.

Condensed abstract

The EuroCMR registry sought to evaluate indications, image quality, safety and impact on patient management of clinical routine CMR in a multi-national European setting in a large number of cases (n > 27000). Based on our data CMR is frequently performed in European daily clinical routine. The most important indications in Europe are risk stratification in suspected CAD/Ischemia, work-up of myocarditis and cardiomyopathies, as well as assessment of viability. CMR imaging is a safe procedure, has diagnostic image quality in more than 98% of cases, and its results have strong impact on patient management. Interim analyses of the specific protocols underscore the prognostic value of clinical routine CMR in CAD and HCM.     

Failed efficacy of soluble human CD83-Ig in allogeneic mixed lymphocyte reactions and experimental autoimmune encephalomyelitis: implications for a lack of therapeutic potential

Soluble forms of CD83, a dendritic cell-specific surface glycoprotein, have been strongly proposed to be of therapeutic utility in inflammatory conditions such as multiple sclerosis and transplantation. We demonstrate here, however, that eukaryotically expressed, recombinant soluble human CD83-Ig molecules fail to achieve efficacy in model systems for those conditions: mouse experimental autoimmune encephalomyelitis models in vivo or in mixed lymphocyte reactions in vitro. These results raise concern as to the viability of a eukaryotically expressed soluble CD83 strategy for clinical therapeutic use.     

Spermine and Endothelial Damage During Endotoxemia

Diazenolate-NO-donors like spermine-NONOate use spermine as a nitric oxide releasing carrier. As one of the naturally occurring polyamines, spermine belongs to the most potent platelet aggregation inhibitors among the polyamines. Recent publications describe a dominating role for platelets and nitric oxide in the setting of endothelial dysfunction during endotoxemia. It is unknown whether spermine as single agent, beside his function as nitric oxide releasing carrier, exerts effects on macromolecular leakage during early endotoxemia. In male Wistar rats, macromolecular efflux was determined in mesenteric postcapillary venules using intravital microscopy at baseline, 60 and 120 min after the start of the experiment. In the first part of the experiments we investigated the effects of spermine and spermine-NONOate during leukocyte-independent states of endotoxemia, using the L- and P-selectin inhibitor fucoidin to suppress leukocyte-endothelial-interaction. In the second part we investigated the effects of spermine on endothelial damage during endotoxemia without co-administration of fucoidin. Combined treatment of animals with spermine and fucoidin was as effective as treatment with spermine-NONOate and fucoidin alone. Spermine and fucoidin as single agents had no effects on macromolecular efflux during endotoxin challenge. Combined treatment of animals with spermine and fucoidin reduce macromolecular efflux to the same degree like treatment with spermine-NONOate and fucoidin. A currently unknown interaction between fucoidin and spermine leads to a significant reduction in macromolecular efflux.