An RNA Hybridization Assay for Screening Influenza A Virus Polymerase Inhibitors Using the Entire Ribonucleoprotein Complex

Novel antiviral drugs, which are less prone to resistance development, are desirable alternatives to the currently approved drugs for the treatment of potentially serious influenza virus infections. The viral polymerase is highly conserved and serves as an attractive target for antiviral drugs since potent inhibitors would directly stop viral replication at an early stage. Recent structural studies on the functional domains of the heterotrimeric influenza polymerase, which comprises subunits PA, PB1, and PB2, opened the way to a structure-based approach for optimizing inhibitors of viral replication. These strategies, however, are limited by the use of isolated protein fragments instead of employing the entire ribonucleoprotein complex (RNP), which represents the functional form of the influenza polymerase in infected cells. In this study, we have established a screening assay for efficient and reliable analysis of potential influenza polymerase inhibitors of various molecular targets such as monoselective polymerase inhibitors targeting the endonuclease site, the cap-binding domain, and the polymerase active site, respectively. By utilizing whole viral RNPs and a radioactivity-free endpoint detection with the capability for efficient compound screening while offering high-content information on potential inhibitors to drive medicinal chemistry program in a reliable manner, this biochemical assay provides significant advantages over the currently available conventional assays. We propose that this assay can eventually be adapted for coinstantaneous analysis and subsequent optimization of two or more different chemical scaffold classes targeting multiple active sites within the polymerase complex, thus enabling the evaluation of drug combinations and characterization of molecules with dual functionality.

Effects of positive blood alcohol concentration on outcome and systemic interleukin-6 in major trauma patients

BACKGROUND

The influence of alcohol on the outcome after major trauma remains controversial. In several recent studies, alcohol has been associated with neuroprotective effects in head injuries, while others reported negative or no effects on survival and/or the in-hospital stay in major trauma patients (TP). The purpose of this study was to examine the relationship of alcohol with injury characteristics and outcome as well as to analyze possible anti-inflammatory properties in major TP.

PATIENTS/METHODS

184 severely injured TP with an Injury Severity Score (ISS) ≥16 were successively enrolled. All patients had measured blood alcohol concentration (BAC). Patients were grouped according to their positive BAC (>0.5‰, BAC) vs. <0.5‰ alcohol (no BAC) upon arrival at the emergency department (ED). Injury characteristics, physiologic parameters and outcome with respect to organ or multiple organ failure (MOF), SIRS, sepsis, pneumonia, ARDS or mortality were assessed. Systemic levels of interleukin (IL)-6 at ED were determined.

RESULTS

Forty-nine TP had positive BAC without chronic alcohol abuse history and 135 patients had BAC levels below 0.5‰. Overall injury severity and age were comparable in both groups. No BAC TP received significantly higher numbers of packed red blood cells and fresh frozen plasma (transfused within the initial 24h or in total) compared to BAC TP. Organ failure, MOF, SIRS, sepsis, pneumonia, ARDS and the in-hospital mortality were not different between both groups. Trauma patients with positive BAC had significantly decreased leukocyte numbers and systemic IL-6 levels compared to no BAC group. There was a significant positive correlation between leukocyte counts and IL-6 as well as BAC and leukocytes. BAC levels did not correlate with IL-6.

CONCLUSIONS

Positive BAC is associated with reduced leukocyte numbers and lowered systemic IL-6 levels at admittance indicating immune-suppressive effects of alcohol in major trauma patients.

Current role of cardiac and extra-cardiac pathologies in clinically indicated cardiac computed tomography with emphasis on status before pulmonary vein isolation

PURPOSE

The aim of this study was to assess the incidence of cardiac and significant extra-cardiac findings in clinical computed tomography of the heart in patients with atrial fibrillation before pulmonary vein isolation (PVI).

MATERIALS AND METHODS

224 patients (64 ± 10 years; male 63 %) with atrial fibrillation were examined by cardiac 64-slice multidetector CT before PVI. Extra-cardiac findings were classified as "significant" if they were recommended to additional diagnostics or therapy, and otherwise as "non-significant". Additionally, cardiac findings were documented in detail.

RESULTS

A total of 724 cardiac findings were identified in 203 patients (91 % of patients). Additionally, a total of 619 extra-cardiac findings were identified in 179 patients (80 % of patients). Among these extra-cardiac findings 196 (32 %) were "significant", and 423 (68 %) were "non-significant". In 2 patients (1 %) a previously unknown malignancy was detected (esophageal cancer and lung cancer, local stage, no metastasis). 203 additional imaging diagnostics followed to clarify the "significant" findings (124 additional CT, costs 38 314.69 US dollars). Overall, there were 3.2 cardiac and 2.8 extra-cardiac findings per patient. Extra-cardiac findings appear significantly more frequently in patients over 60 years old, in smokers and in patients with a history of cardiac findings (p <0.05).

CONCLUSION

Cardiac CT scans before PVI should be screened for extracardiac incidental findings that could have important clinical implications for each patient.

Using ovality to predict nonmutagenic, orally efficacious pyridazine amides as cell specific spleen tyrosine kinase inhibitors

Inhibition of spleen tyrosine kinase has attracted much attention as a mechanism for the treatment of cancers and autoimmune diseases such as asthma, rheumatoid arthritis, and systemic lupus erythematous. We report the structure-guided optimization of pyridazine amide spleen tyrosine kinase inhibitors. Early representatives of this scaffold were highly potent and selective but mutagenic in an Ames assay. An approach that led to the successful identification of nonmutagenic examples, as well as further optimization to compounds with reduced cardiovascular liabilities is described. Select pharmacokinetic and in vivo efficacy data are presented.

Always expect the unexpected: lung abscess due to pseudomonas aeruginosa mimicking pulmonary aspergilloma in acute B-cell leukemia

We report on a case of Pseudomonas aeruginosa sepsis and consecutive lung abscess in a 13-year-old patient with acute B-cell leukemia. At first, radiographic findings strongly suggested presence of pulmonary aspergilloma and only microbiological testing of the surgically enucleated mass revealed the correct underlying pathogen and confirmed final diagnosis.

Selective inhibition of spleen tyrosine kinase (SYK) with a novel orally bioavailable small molecule inhibitor, RO9021, impinges on various innate and adaptive immune responses: implications for SYK inhibitors in autoimmune disease therapy

Introduction

Spleen tyrosine kinase (SYK) is a key integrator of intracellular signals triggered by activated immunoreceptors, including Bcell receptors (BCR) and Fc receptors, which are important for the development and function of lymphoid cells. Given the clinical efficacy of Bcell depletion in the treatment of rheumatoid arthritis and multiple sclerosis, pharmacological modulation of Bcells using orally active small molecules that selectively target SYK presents an attractive alternative therapeutic strategy.

Methods

A SYK inhibitor was developed and assayed in various in vitro systems and in the mouse model of collagen-induced arthritis (mCIA).

Results

A novel ATP-competitive inhibitor of SYK, 6-[(1R,2S)-2-Amino-cyclohexylamino]-4-(5,6-dimethyl-pyridin-2-ylamino)-pyridazine-3-carboxylic acid amide, designated RO9021, with an adequate kinase selectivity profile and oral bioavailability, was developed. In addition to suppression of BCR signaling in human peripheral blood mononuclear cells (PBMC) and whole blood, FcγR signaling in human monocytes, and FcϵR signaling in human mast cells, RO9021 blocked osteoclastogenesis from mouse bone marrow macrophages in vitro. Interestingly, Toll-like Receptor (TLR) 9 signaling in human Bcells was inhibited by RO9021, resulting in decreased levels of plasmablasts, immunoglobulin (Ig) M and IgG upon B-cell differentiation. RO9021 also potently inhibited type I interferon production by human plasmacytoid dendritic cells (pDC) upon TLR9 activation. This effect is specific to TLR9 as RO9021 did not inhibit TLR4- or JAK-STAT-mediated signaling. Finally, oral administration of RO9021 inhibited arthritis progression in the mCIA model, with observable pharmacokinetics (PK)-pharmacodynamic (PD) correlation.

Conclusions

Inhibition of SYK kinase activity impinges on various innate and adaptive immune responses. RO9021 could serve as a starting point for the development of selective SYK inhibitors for the treatment of inflammation-related and autoimmune-related disorders.

Metal impurities cause false positives in high-throughput screening campaigns

Organic impurities in compound libraries are known to often cause false-positive signals in screening campaigns for new leads, but organic impurities do not fully account for all false-positive results. We discovered inorganic impurities in our screening library that can also cause positive signals for a variety of targets and/or readout systems, including biochemical and biosensor assays. We investigated in depth the example of zinc for a specific project and in retrospect in various HTS screens at Roche and propose a straightforward counter screen using the chelator TPEN to rule out inhibition caused by zinc.

Glioma infiltration of the corpus callosum: early signs detected by DTI

The most frequent primary brain tumors, anaplastic astrocytomas (AA) and glioblastomas (GBM): tend to invasion of the surrounding brain. Histopathological studies found malignant cells in macroscopically unsuspicious brain parenchyma remote from the primary tumor, even affecting the contralateral hemisphere. In early stages, diffuse interneural infiltration with changes of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) is suspected. The purpose of this study was to investigate the value of DTI as a possible instrument of depicting evidence of tumor invasion into the corpus callosum (CC). Preoperatively, 31 patients with high-grade brain tumors (8 AA and 23 GBM) were examined by MRI at 3 T, applying a high-resolution diffusion tensor imaging (DTI) sequence. ADC- and FA-values were analyzed in the tumor-associated area of the CC as identified by fiber tracking, and were compared to matched healthy controls. In (MR-)morphologically normal appearing CC the ADC values were elevated in the tumor patients (n = 22; 0.978 × 10⁻³ mm²/s) compared to matched controls (0.917 × 10⁻³ mm²/s, p < 0.05), and the corresponding relative FA was reduced (rFA: 88 %, p < 0.01). The effect was pronounced in case of affection of the CC visible on MRI (n = 9; 0.978 × 10⁻³ mm²/s, p < 0.05; rFA: 72 %, p < 0.01). Changes in diffusivity and anisotropy in the CC can be interpreted as an indicator of tumor spread into the contralateral hemisphere not visible on conventional MRI.

3-Amido pyrrolopyrazine JAK kinase inhibitors: development of a JAK3 vs JAK1 selective inhibitor and evaluation in cellular and in vivo models

The Janus kinases (JAKs) are involved in multiple signaling networks relevant to inflammatory diseases, and inhibition of one or more members of this class may modulate disease activity or progression. We optimized a new inhibitor scaffold, 3-amido-5-cyclopropylpyrrolopyrazines, to a potent example with reasonable kinome selectivity, including selectivity for JAK3 versus JAK1, and good biopharmaceutical properties. Evaluation of this analogue in cellular and in vivo models confirmed functional selectivity for modulation of a JAK3/JAK1-dependent IL-2 stimulated pathway over a JAK1/JAK2/Tyk2-dependent IL-6 stimulated pathway.

Nicotinic acid and DP1 blockade: studies in mouse models of atherosclerosis

The use of nicotinic acid to treat dyslipidemia is limited by induction of a "flushing" response, mediated in part by the interaction of prostaglandin D(2) (PGD(2)) with its G-protein coupled receptor, DP1 (Ptgdr). The impact of DP1 blockade (genetic or pharmacologic) was assessed in experimental murine models of atherosclerosis. In Ptgdr(-/-)ApoE(-/-) mice versus ApoE(-/-) mice, both fed a high-fat diet, aortic cholesterol content was modestly higher (1.3- to 1.5-fold, P < 0.05) in Ptgdr(-/-)ApoE(-/-) mice at 16 and 24 weeks of age, but not at 32 weeks. In multiple ApoE(-/-) mouse studies, a DP1-specific antagonist, L-655, generally had a neutral to beneficial effect on aortic lipids in the presence or absence of nicotinic acid treatment. In a separate study, a modest increase in some atherosclerotic measures was observed with L-655 treatment in Ldlr(-/-) mice fed a high-fat diet for 8 weeks; however, this effect was not sustained for 16 or 24 weeks. In the same study, treatment with nicotinic acid alone generally decreased plasma and/or aortic lipids, and addition of L-655 did not negate those beneficial effects. These studies demonstrate that inhibition of DP1, with or without nicotinic acid treatment, does not lead to consistent or sustained effects on plaque burden in mouse atherosclerotic models.

Peripherally circulating CD4⁺ FOXP3⁺ CXCR3⁺ T regulatory cells correlate with renal allograft function

Peripheral immunoregulation depends on T regulatory cell trafficking into the allograft to modulate the local alloresponse. Little is known about the relevance of trafficking receptors for Tregs after solid organ transplantation in humans. In this study, expression of the peripheral chemokine receptors CXCR3 and CCR5 on CD4⁺ FOXP3⁺ Treg cells was analysed and correlated with allograft function in renal transplant recipients. Flow cytometry analysis of peripheral blood mononuclear cells of 54 renal transplant recipients receiving a calcineurin inhibitor-based immunosuppression was performed for CD4, CD25, FOXP3, CXCR3 and CCR5 within the first 18 months post-transplantation. Correlation analysis of chemokine receptor expression and glomerular filtration rate as calculated by MDRD (eGFR) was performed. Expression of the peripheral homing receptors CXCR3 (r = 0.44, P < 0.05) and CCR5 (r = 0.45, P < 0.05) on FOXP3⁺ Tregs correlated with renal allograft function (eGFR) in patients receiving tacrolimus (n = 28), but not cyclosporine A (CsA) (n = 26). CsA but not tacrolimus reduced surface expression of CXCR3 on FOXP3⁺ Tregs in renal transplant recipients as correlated to trough levels (r = -0.42, P < 0.05). In contrast to CD4⁺ CXCR3⁺ CD25(lo) T cells, flow-sorted CD4⁺ CXCR3⁺ CD25(hi) Tregs isolated from healthy individuals did not produce IFNγ or IL-17 ex vivo and expressed high levels of GARP mRNA both at baseline as well as after TCR activation indicating functional regulatory activity. Expression of the peripheral trafficking receptors CXCR3 and CCR5 on FOXP3⁺ Tregs is associated with renal allograft function. These results suggest that Treg trafficking may also depend on the interaction of CXCR3 or CCR5 and their respective ligands.

A gene expression signature that classifies human atherosclerotic plaque by relative inflammation status

BACKGROUND

Atherosclerosis is a complex disease requiring improvements in diagnostic techniques and therapeutic treatments. Both improvements will be facilitated by greater exploration of the biology of atherosclerotic plaque. To this end, we carried out large-scale gene expression analysis of human atherosclerotic lesions.

METHODS AND RESULTS

Whole genome expression analysis of 101 plaques from patients with peripheral artery disease identified a robust gene signature (1514 genes) that is dominated by processes related to Toll-like receptor signaling, T-cell activation, cholesterol efflux, oxidative stress response, inflammatory cytokine production, vasoconstriction, and lysosomal activity. Further analysis of gene expression in microdissected carotid plaque samples revealed that this signature is differentially expressed in macrophage-rich and smooth muscle cell-containing regions. A quantitative PCR gene expression panel and inflammatory composite score were developed on the basis of the atherosclerotic plaque gene signature. When applied to serial sections of carotid plaque, the inflammatory composite score was observed to correlate with histological and morphological features related to plaque vulnerability.

CONCLUSIONS

The robust mRNA expression signature identified in the present report is associated with pathological features of vulnerable atherosclerotic plaque and may be useful as a source of biomarkers and targets of novel antiatherosclerotic therapies.

Bivariate random-effects meta-analysis of sensitivity and specificity with SAS PROC GLIMMIX

OBJECTIVES

Meta-analysis allows to summarize pooled sensitivities and specificities from several primary diagnostic test accuracy studies. Often these pooled estimates are indirectly obtained from a hierarchical summary receiver operating characteristics (HSROC) analysis. This article presents a generalized linear random-effects model with the new SAS PROC GLIMMIX that obtains the pooled estimates for sensitivity and specificity directly.

METHODS

Firstly, the formula of the bivariate random-effects model is presented in context with the literature. Then its implementation with the new SAS PROC GLIMMIX is empirically evaluated in comparison to the indirect HSROC approach, utilizing the published 2 x 2 count data of 50 meta-analyses.

RESULTS

According to the empirical evaluation the meta-analytic results from the bivariate GLIMMIX approach are nearly identical to the results from the indirect HSROC approach.

CONCLUSIONS

A generalized linear mixed model with PROC GLIMMIX offers a straightforward method for bivariate random-effects meta-analysis of sensitivity and specificity.

Interventions for cutaneous molluscum contagiosum

BACKGROUND

Molluscum contagiosum is a common skin infection, caused by a virus, which will usually resolve within months in people with a normal immune system. Many treatments have been promoted for molluscum contagiosum but a clear evidence base supporting them is lacking.

OBJECTIVES

To assess the effects of management strategies (including waiting for natural resolution) for cutaneous, non-genital molluscum contagiosum in healthy people.

SEARCH STRATEGY

We searched the Skin Group Specialised Register (March 2004), the Cochrane Central Register of Controlled Trials (2004, Issue 2), MEDLINE (from 1966 to March 2004), EMBASE (from 1980 to March 2004) and LILACS (from 1982 to March 2004) databases. We also searched reference lists and contacted pharmaceutical companies and experts in the field.

SELECTION CRITERIA

Randomised controlled trials for treatment of molluscum contagiosum were investigated. Trials on sexually transmitted molluscum contagiosum and in people with lowered immunity (including those with HIV infection) were excluded.

DATA COLLECTION AND ANALYSIS

Study selection and assessment of methodological quality were carried out by two independent authors. As similar comparisons between two interventions were not made in more than one study, statistical pooling was not performed.

MAIN RESULTS

Five studies, with a total number of 137 participants, examined the effects of topical (three studies), systemic and homoeopathic interventions (one study each). Limited evidence was found for sodium nitrite co-applied with salicylic acid compared to salicylic acid alone (risk ratio (RR) 3.50, 95% confidence interval (CI) 1.23 to 9.92). No statistically significant differences were found for topical povidone iodine plus salicylic acid compared to povidone iodine alone (RR of cure 1.67, 95% CI 0.81 to 3.41) or compared to salicylic acid alone. Also no statistically significant differences were found for potassium hydroxide compared to placebo; systemic treatment with cimetidine versus placebo or systemic treatment with calcarea carbonica, a homoeopathic drug, versus placebo (RR 5.57, 95% CI 0.93 to 33.54). Study limitations included no blinding (two studies), many dropouts (three studies) and no intention-to-treat analysis (two studies); small study sizes may have led to important differences being missed. None of the evaluated treatment options were associated with serious adverse effects.

AUTHORS' CONCLUSIONS

No single intervention has been shown to be convincingly effective in treating molluscum contagiosum.

Cerebral oxygenation and hemodynamics during blood donation studied by near-infrared spectroscopy

BACKGROUND

Blood donation is a safe human model for acute blood loss. This study investigated associated changes in regional cerebral oxygenation and cerebral blood volume (CBV) by near-infrared spectroscopy (NIRS).

STUDY DESIGN AND METHODS

Fifty healthy blood donors donated 450 mL of whole blood within 4 to 9 minutes. Changes in regional cerebral oxygen saturation (rSO2) and cerebral tissue Hb concentration (HbT) were semiquantitatively measured by NIRS. Venous Hb concentration was measured before and after blood donation. The predonation and postdonation CBV was estimated from HbT and venous Hb concentration. Differences between pre- and postdonation study parameters were analyzed by paired t tests (p < 0.05).

RESULTS

Within the study group, rSO2 decreased by 0.44 sat percent (p < 0.01) on average during blood donation, which is still within the range of individual physiologic baseline variation. The average venous Hb concentration decreased significantly by 4.6 percent, whereas HbT increased significantly by 2.5 percent and CBV increased even by 7.5 percent on average.

CONCLUSION

The increase in CBV indicates cerebral vasodilation, which seems to be the major compensation mechanism during acute blood loss. The decrease in rSO2 was relatively small, indicating that cerebral oxygenation was maintained within the physiologic range.

Characterization and genomic analysis of tobacco vein clearing virus, a plant pararetrovirus that is transmitted vertically and related to sequences integrated in the host genome

A previously undescribed caulimo-like virus was identified in the hybrid tobacco species Nicotiana edwardsonii, and was named tobacco vein clearing virus (TVCV) after the symptoms associated with its occurrence in this plant. The virions of TVCV are 50 nm in diameter and are composed of a 45 kDa capsid protein and a 7767 bp dsDNA genome. Each strand of the genome is interrupted by a site-specific discontinuity. In genome sequence and arrangement of ORFs TVCV was most similar to cassava vein mosaic virus, indicating that TVCV is a pararetrovirus. No serological relationship was detected between TVCV and any other caulimoviruses, including petunia vein clearing virus, which has similar biological properties. In N. edwardsonii TVCV was seed-transmitted to 100% of progeny plants, but was not transmitted by mechanical inoculation, grafting or Myzus persicae to any of seven other Nicotiana spp. Genomic DNA of TVCV hybridized to genomic DNA of N. edwardsonii and of N. glutinosa, its male parent, but not to genomic DNA of N. clevelandii, the female parent. TVCV has 78% sequence identity with pararetrovirus-like sequences that are present in high copy number in the N. tabacum genome, and TVCV genomic DNA hybridized to genomic DNA of N. tabacum and N. rustica. These observations suggest that the episomal form of TVCV may arise from integrated pararetroviral elements present in N. edwardsonii, that these integrants were inherited from the male parent N. glutinosa, and that these elements are related but not identical to pararetroviral elements occurring in other Nicotiana spp.