Optimization and preclinical evaluation of novel histamine H3 receptor ligands: Acetyl and propionyl phenoxyalkyl piperazine derivatives

As a continuation of our search for novel histamine H₃ receptor ligands, a series of new acetyl and propionyl phenoxyalkylamine derivatives (2–25) was synthesized. Compounds with three to four carbon atoms alkyl chain spacer, composed of six various 4N-substituted piperazine moieties were evaluated for their binding properties at human histamine H₃ receptors (hH₃R). In vitro test results proved the 4-pyridylpiperazine moiety as crucial element for high hH₃R affinity (hH₃R K_i?=?5.2–115?nM). Moreover introduction of carbonyl group containing residues in the lipophilic part of molecules instead of branched alkyl substituents resulted in increased affinity in correlation to previously described series, whereas propionyl derivatives showed slightly higher affinities than those of acetyl (16 and 22vs.4 and 10; hH₃R K_i?=?5.2 and 15.4?nM vs. 10.2 and 115?nM, respectively). These findings were confirmed by molecular modelling studies, demonstrating multiple ligand-receptor interactions. Furthermore, pharmacological in vivo test results of compound 4 clearly indicate that it may affect the amount of calories consumed, thus act as an anorectic compound. Likewise, its protective action against hyperglycemia and the development of overweight has been shown. In order to estimate drug-likeness of compound 4, in silico and experimental evaluation of metabolic stability in human liver microsomes was performed.     

EPR Oximetry Sensor—Developing a TAM Derivative for In Vivo Studies

Oxygenation is one of the most important physiological parameters of biological systems. Low oxygen concentration (hypoxia) is associated with various pathophysiological processes in different organs. Hypoxia is of special importance in tumor therapy, causing poor response to treatment. Triaryl methyl (TAM) derivative radicals are commonly used in electron paramagnetic resonance (EPR) as sensors for quantitative spatial tissue oxygen mapping. They are also known as magnetic resonance imaging (MRI) contrast agents and fluorescence imaging compounds. We report the properties of the TAM radical tris(2,3,5,6-tetrachloro-4-carboxy-phenyl)methyl, (PTMTC), a potential multimodal (EPR/fluorescence) marker. PTMTC was spectrally analyzed using EPR and characterized by estimation of its sensitivity to the oxygen in liquid environment suitable for intravenous injection (1?mM PBS, pH?=?7.4). Further, fluorescent emission of the radical was measured using the same solvent and its quantum yield was estimated. An in vitro cytotoxicity examination was conducted in two cancer cell lines, HT-29 (colorectal adenocarcinoma) and FaDu (squamous cell carcinoma) and followed by uptake studies. The stability of the radical in different solutions (PBS pH?=?7.4, cell media used for HT-29 and FaDu cells culturing and cytotoxicity procedure, full rat blood and blood plasma) was determined. Finally, a primary toxicity test of PTMTC was carried out in mice. Results of spectral studies confirmed the multimodal properties of PTMTC. PTMTC was demonstrated to be not absorbed by cancer cells and did not interfere with luciferin-luciferase based assays. Also in vitro and in vivo tests showed that it was non-toxic and can be freely administrated till doses of 250?mg/kg BW via both i.v. and i.p. injections. This work illustrated that PTMTC is a perfect candidate for multimodal (EPR/fluorescence) contrast agent in preclinical studies.     

Phylogenetic positions of seven poorly known species of Ferula (Apiaceae) with remarks on the phylogenetic utility of the plastid trnH-psbA,trnS-trnG,and atpB-rbcL intergenic spacers

Ferula L. is one of the most species-rich and taxonomically difficult genera of Apiaceae. In this study, we obtained nrDNA ITS sequences of seven poorly known species of Ferula (Ferula anatolica, Ferula sp. (tentatively identified as F. candelabrum by collectors), F. drudeana, F. huber-morathii, F. marmarica, F. talassica, and F. tunetana) and explored their phylogenetic positions using 148 ITS sequences of the subtribe Ferulinae from GenBank. Five of these newly sequenced species fall into three groups, corresponding to clades recognized in earlier molecular studies. Ferula sp. are added to clade, which is mostly composed of Central Asian species. This placement showed that identification as F. candelabrum was erroneous. The second clade, which is mostly composed of Mediterranean taxa, includes two species from North Africa: F. marmarica and F. tunetana. Despite the well-supported monophyly of this clade, the relationships inside this group need to be revised, as broadly distributed F. communis is paraphyletic with respect to other species. Ferula drudeana and F. huber-morathii, two narrow endemics from Turkey, are placed in the Central Asian clade. Two species, F. anatolica and F. talassica, do not fall into any of the recognized clades. In addition, we examined the sequence variation of three potentially highly variable pDNA regions, the trnH-psbA, trnS-trnG, and atpB-rbcL intergenic spacers, for a subset of 18 specimens. The resulting pDNA and ITS based phylogenetic trees were incongruent, as supported by significant ILD tests. The cause of this incongruence can be manifold, including hybridization, a lack of a phylogenetic signal, and homoplastic substitutions. Our analyses suggest that only trnS-trnG can be added to the list of pDNA markers used for phylogenetic studies of Ferula, as it has the highest number of parsimony informative characters and is easy to amplify from degraded material.     

Long-term follow-up in adults after tetralogy of Fallot repair

Background

Tetralogy of Fallot (ToF) is the most common cyanotic congenital heart disease and the population of ToF repair survivors is growing rapidly. Adults with repaired ToF develop late complications. The aim of this study was to describe and analyze long-term follow-up of patients with repaired ToF.

Methods

This is a retrospective cohort study. Consecutive 83 patients with repaired ToF who did not undergo pulmonary valve replacement were included. Mean age of all patients was 30.5?±?10.7. There were 49 (59%) male. Patients were divided into two groups according to the time since the repair (<?25 years and?≥?25 years). The electrocardiographic (ECG), cardiopulmonary exercise testing (CPET), echocardiographic and cardiac magnetic resonance (CMR) data were reviewed retrospectively.

Results

In CPET values were not significantly different in the two groups. In CMR volumes of left and right ventricles were not significantly different in the two groups. There were no differences between the groups in ventricular ejection fraction, mass of ventricles, or pulmonary regurgitation fraction. Among all the patients, ejection fraction and left and right ventricle mass, indexed pulmonary regurgitation volume measured by CMR did not correlate with the time since repair. In ECG among all the patients, ejection fraction of the RV, measured in CMR, negatively correlated with QRS duration (r?=???0.43; p?<?0.001). There was a positive correlation between QRS duration and end diastolic volume of the RV (r?=?0.30; p?<?0.02), indexed end diastolic volume of the RV (r?=?0.29; p?=?0.04), RV mass (r?=?0.36; p?<?0.001) and left ventricle mass (r?=?0.26; p?=?0.04).

Conclusion

Long-term survival and clinical condition after surgical correction of ToF in infancy is generally good and the late functional status in ToF – operated patients could be excellent up to 25 years after the repair. QRS duration could be an utility and easy factor to assessment of right ventricular function.

Trial registration

The study protocol was approved by the local Ethics Committee. Each participant provided informed consent to participate in the study (license number 122.6120.88.2016 from 28.04.2016).

     

Tumor microenvironment – Unknown niche with powerful therapeutic potential

Head and neck squamous cell carcinomas (HNSCC) are in a group of cancers that are the most resistant to treatment. The survival rate of HNSCC patients has been still very low since last 20 years. The existence of relationship between oncogenic and surrounding cells is probably the reason for a poor response to treatment. Fibroblasts are an important element of tumor stroma which increases tumor cells ability to proliferate. Another highly resistance, tumorigenic and metastatic cell population in tumor microenvironment are cancer initiating cells (CICs). The population of cancer initiating cells can be found regardless of differentiation status of cancer and they seem to be crucial for HNSCC development.In this review, we describe the current state of knowledge about HNSCC biological and physiological tumor microenvironment.     

Synthesis and cytotoxic activity of novel acyclic nucleoside analogues with functionality in click chemistry

We describe synthesis of novel acyclic nucleoside analogues which are building blocks for CuAAC reaction and their activity against two types of human cancer cell lines (HeLa, KB). Three of chosen compounds show promising cytotoxic activity. Synthesis pathway starting from simple and easily accessible substrates employing DMT or TBDPS protective groups is described. Adenosine and thymidine analogues containing alkyne moiety and adenosine analogue containing azido group were synthesized. The obtained units showed ability of forming triazole motif under the CuAAC reaction conditions.     

Analysis of the long-term stability of the output of electron beams generated by the Novac11™ IORT accelerator

Aim

The aim of the study was to analyze the long-term stability of electron beams generated by the Novac11? IORT accelerator.

Lymphocyte responses of rats vaccinated with cDNA encoding a phosphoglycerate kinase of Fasciola hepatica (FhPGK) and F. hepatica infection

Lymphocyte responses in the blood, peritoneal fluid and both mesenteric and hepatic lymph nodes of cDNA-FhPGK/pCMV vaccinated and/or Fasciola hepatica infected rats of both sexes were investigated to provide an insight into the immune responses that develop in different body compartments. The immune response that developed in cDNA-FhPGK/pCMV vaccinated females contributed to partial protection against F. hepatica infection (54% reduction in fluke recovery), while more liver flukes were found in the livers and bile ducts of cDNA-FhPGK/pCMV vaccinated male rats than in unvaccinated animals (increase of 13%). Rat sex not only affected the ultimate effectiveness of vaccination but also lymphocyte responses following vaccination and/or infection. Different CD4 + and CD8 + T cell profiles were noted in peritoneal fluid and lymph nodes, but not in blood, during acute and chronic fasciolosis. Moreover, independent lymphocyte responses developed in distinct body compartments. Immune responses of rats were polarized towards Th2/Treg with lymphocytes isolated from male rats showing higher IL-4 and IL-10 production than females. Lymphocyte proliferative capacities in response to mitogen (PHA) or vaccine antigen (FhPGK) were impaired in both sexes with a considerably higher reduction observed for males and restored lymphocyte proliferative capacities reported for females vaccinated with cDNA-FhPGK/pCMV during chronic fasciolosis.     

2-OMe-lysophosphatidylcholine analogues are GPR119 ligands and activate insulin secretion from βTC-3 pancreatic cells: Evaluation of structure-dependent biological activity

GPR119 receptor has been proposed as a metabolic regulator playing a pivotal role in the modulation of glucose homeostasis in type 2 diabetes. GPR119 was identified on pancreatic β cells and its ligands have the ability to enhance glucose-stimulated insulin secretion (GSIS). Lysophosphatidylcholine (LPC) was shown to potentiate GSIS and our present studies indicate that 2-methoxy-lysophosphatidylcholine (2-OMe-LPC) analogues, unable to undergo 1 → 2 acyl migration, stimulate GSIS from murine βTC-3 pancreatic cells even more efficiently. Moreover, biological assays in engineered Tango? GPR119-bla U2OS cells were carried out to ascertain the agonist activity of 2-OMe-LPC at GPR119. 2-OMe-LPC possessing in sn-1 position the residues of myristic, palmitic, stearic and oleic acid were also evaluated as factors regulating [Ca^2 +]_i mobilization and cAMP levels. Extension of these studies to R- and S-enantiomers of 14:0 2-OMe-LPC revealed that the overall impact on GSIS does not depend on chirality, however, the intracellular calcium mobilization data show that the R enantiomer is significantly more active than S one. Taking into account differences in chemical structure between various native LPCs and their 2-methoxy counterparts the possible binding mode of 2-OMe-LPC to the GPR119 receptor was determined using molecular modeling approach.