A novel series of histamine H4 receptor antagonists based on the pyrido[3,2-d]pyrimidine scaffold: Comparison of hERG binding and target residence time with PF-3893787

In this work we describe the optimization of a lead compound based on the quinazoline template to give a new series of potent pyrido[3,2-d]pyrimidines as histamine H₄ receptor antagonists. The pyrido[3,2-d]pyrimidine ligands have significantly reduced hERG binding compared to clinical stage compound PF-3893787 while showing good affinities at the human and rodent histamine receptors. The receptor residence time of several of these new compounds was determined for the human H₄R and compared with JNJ7777120 and PF-3893787. The pyrido[3,2-d]pyrimidines showed residence times lower than JNJ7777120 but comparable to the residence time of PF-3893787. Overall, the pyrido[3,2-d]pyrimidines show an excellent in vitro profile that warrants their further investigation in relevant models of human disease.     

Identification of a new genotype of Torque Teno Mini virus

Background

Since we were able to isolate viable virus from brain and lung of H7N1 low pathogenic avian influenza virus (LPAIV) infected chickens, we here examined the distribution of different LPAIV strains in chickens by measuring the viral AI RNA load in multiple organs. Subtypes of H5 (H5N1, H5N2), H7 (H7N1, H7N7) and H9 (H9N2), of chicken (H5N2, H7N1, H7N7, H9N2), or mallard (H5N1) origin were tested. The actual presence of viable virus was evaluated with virus isolation in organs of H7N7 inoculated chickens.

Findings

Viral RNA was found by PCR in lung, brain, intestine, peripheral blood mononuclear cells, heart, liver, kidney and spleen from chickens infected with chicken isolated LPAIV H5N2, H7N1, H7N7 or H9N2. H7N7 virus could be isolated from lung, ileum, heart, liver, kidney and spleen, but not from brain, which was in agreement with the data from the PCR. Infection with mallard isolated H5N1 LPAIV resulted in viral RNA detection in lung and peripheral blood mononuclear cells only.

Conclusion

We speculate that chicken isolated LPAI viruses are spreading systemically in chicken, independently of the strain.     

Urogenital Chlamydia trachomatis Infections among Ethnic Groups in Paramaribo,Suriname; Determinants and Ethnic Sexual Mixing Patterns

Background

Little is known about the epidemiology of urogenital Chlamydia trachomatis infection (chlamydia) in Suriname. Suriname is a society composed of many ethnic groups, such as Creoles, Maroons, Hindustani, Javanese, Chinese, Caucasians, and indigenous Amerindians. We estimated determinants for chlamydia, including the role of ethnicity, and identified transmission patterns and ethnic sexual networks among clients of two clinics in Paramaribo, Suriname.

Methods

Participants were recruited at two sites a sexually transmitted infections (STI) clinic and a family planning (FP) clinic in Paramaribo. Urine samples from men and nurse-collected vaginal swabs were obtained for nucleic acid amplification testing. Logistic regression analysis was used to identify determinants of chlamydia. Multilocus sequence typing (MLST) was performed to genotype C. trachomatis. To identify transmission patterns and sexual networks, a minimum spanning tree was created, using full MLST profiles. Clusters in the minimum spanning tree were compared for ethnic composition.

Results

Between March 2008 and July 2010, 415 men and 274 women were included at the STI clinic and 819 women at the FP clinic. Overall chlamydia prevalence was 15% (224/1508). Age, ethnicity, and recruitment site were significantly associated with chlamydia in multivariable analysis. Participants of Creole and Javanese ethnicity were more frequently infected with urogenital chlamydia. Although sexual mixing with other ethnic groups did differ significantly per ethnicity, this mixing was not independently significantly associated with chlamydia. We typed 170 C. trachomatis-positive samples (76%) and identified three large C. trachomatis clusters. Although the proportion from various ethnic groups differed significantly between the clusters (P = 0.003), all five major ethnic groups were represented in all three clusters.

Conclusion

Chlamydia prevalence in Suriname is high and targeted prevention measures are required. Although ethnic sexual mixing differed between ethnic groups, differences in prevalence between ethnic groups could not be explained by sexual mixing.     

Feedback from Horizontal Cells to Cones Mediates Color Induction and May Facilitate Color Constancy in Rainbow Trout

Color vision is most beneficial when the visual system is color constant and can correct the excitations of photoreceptors for differences in environmental irradiance. A phenomenon related to color constancy is color induction, where the color of an object shifts away from the color of its surroundings. These two phenomena depend on chromatic spatial integration, which was suggested to originate at the feedback synapse from horizontal cells (HC) to cones. However, the exact retinal site was never determined. Using the electroretinogram and compound action potential recordings, we estimated the spectral sensitivity of the photoresponse of cones, the output of cones, and the optic nerve in rainbow trout. Recordings were performed before and following pharmacological inhibition of HC-cone feedback, and were repeated under two colored backgrounds to estimate the efficiency of color induction. No color induction could be detected in the photoresponse of cones. However, the efficiency of color induction in the cone output and optic nerve was substantial, with the efficiency in the optic nerve being significantly higher than in the cone output. We found that the efficiency of color induction in the cone output and optic nerve decreased significantly with the inhibition of HC-cone feedback. Therefore, our findings suggest not only that color induction originates as a result of HC-cone feedback, but also that this effect of HC-cone feedback is further amplified at downstream retinal elements, possibly through feedback mechanisms at the inner plexiform layer. This study provides evidence for an important role of HC-cone feedback in mediating color induction, and therefore, likely also in mediating color constancy.     

A Meta-Analysis of Retinoblastoma Copy Numbers Refines the List of Possible Driver Genes Involved in Tumor Progression

BackgroundWhile RB1 loss initiates retinoblastoma development, additional somatic copy number alterations (SCNAs) can drive tumor progression. Although SCNAs have been identified with good concordance between studies at a cytoband resolution, accurate identification of single genes for all recurrent SCNAs is still challenging. This study presents a comprehensive meta-analysis of genome-wide SCNAs integrated with gene expression profiling data, narrowing down the list of plausible retinoblastoma driver genes.MethodsWe performed SCNA profiling of 45 primary retinoblastoma samples and eight retinoblastoma cell lines by high-resolution microarrays. We combined our data with genomic, clinical and histopathological data of ten published genome-wide SCNA studies, which strongly enhanced the power of our analyses (N = 310).ResultsComprehensive recurrence analysis of SCNAs in all studies integrated with gene expression data allowed us to reduce candidate gene lists for 1q, 2p, 6p, 7q and 13q to a limited gene set. Besides the well-established driver genes RB1 (13q-loss) and MYCN (2p-gain) we identified CRB1 and NEK7 (1q-gain), SOX4 (6p-gain) and NUP205 (7q-gain) as novel retinoblastoma driver candidates. Depending on the sample subset and algorithms used, alternative candidates were identified including MIR181 (1q-gain) and DEK (6p gain). Remarkably, our study showed that copy number gains rarely exceeded change of one copy, even in pure tumor samples with 100% homozygosity at the RB1 locus (N = 34), which is indicative for intra-tumor heterogeneity. In addition, profound between-tumor variability was observed that was associated with age at diagnosis and differentiation grades.InterpretationSince focal alterations at commonly altered chromosome regions were rare except for 2p24.3 (MYCN), further functional validation of the oncogenic potential of the described candidate genes is now required. For further investigations, our study provides a refined and revised set of candidate retinoblastoma driver genes.     

Comparative Cost-Effectiveness of Drugs in Early versus Late Stages of Cancer; Review of the Literature and a Case Study in Breast Cancer

Background

Many oncological drugs that are being used in the adjuvant setting were first submitted for reimbursement in the metastatic stage, with differences in incremental cost-effectiveness ratios (ICERs) in both settings having potential implications for reimbursement and pricing. The aim of this study is to identify a possible trend in the cost-effectiveness for the early/adjuvant and late/metastatic stages of oncological drugs through review and case study.

Methods

We reviewed pairs of cost-effectiveness analyses of the same oncological drug in different stages for Scotland and the Netherlands. The case study in this report was directed at trastuzumab in the Dutch situation. Using a simplified Markov model, the cost-effectiveness in early and late stage of breast cancer was calculated and compared to the findings from the review.

Results

Comparable studies were found for cetuximab, bortezomib and bosutinib. Treatments in the late stage were found to be more expensive per QALY by a factor ranging from 1.5 to 12. The case study provided a similar result; late stage treatment was more expensive by a factor 10. Using, for example, a threshold of €80,000/QALY, the early stage of cetuximab, bosutinib and trastuzumab are deemed cost-effective, while their compared late stage is lifted over the threshold and potentially considered not cost-effective.

Conclusion

ICERs of oncological drugs used in different stages are more unfavourable in the late stage than in the early stage. Applying a reasonable threshold may result in early stage treatment being deemed cost-effective while late stage potentially not. Authorities should be aware of this when assessing oncological drugs and interpreting the corresponding ICERs, in the situation where oncological drugs are generally most submitted for reimbursement in the late stage initially.     

Fibrin-fiber architecture influences cell spreading and differentiation

ABSTRACT

The mechanical and structural properties of the extracellular matrix (ECM) play an important role in regulating cell fate. The natural ECM has a complex fibrillar structure and shows nonlinear mechanical properties, which are both difficult to mimic synthetically. Therefore, systematically testing the influence of ECM properties on cellular behavior is very challenging. In this work we show two different approaches to tune the fibrillar structure and mechanical properties of fibrin hydrogels. Addition of extra thrombin before gelation increases the protein density within the fibrin fibers without significantly altering the mechanical properties of the resulting hydrogel. On the other hand, by forming a composite hydrogel with a synthetic biomimetic polyisocyanide network the protein density within the fibrin fibers decreases, and the mechanics of the composite material can be tuned by the PIC/fibrin mass ratio. The effect of the changes in gel structure and mechanics on cellular behavior are investigated, by studying human mesenchymal stem cell (hMSC) spreading and differentiation on these gels. We find that the trends observed in cell spreading and differentiation cannot be explained by the bulk mechanics of the gels, but correlate to the density of the fibrin fibers the gels are composed of. These findings strongly suggest that the microscopic properties of individual fibers in fibrous networks play an essential role in determining cell behavior.