Patients’ view of the differences in topical creams for radiation dermatitis prevention. A pilot study of cosmetic properties

AimTo investigate the feasibility of including patients’ reports on the cosmetic properties of topical formulations for acute radiation dermatitis (ARD).BackgroundNo topical agent tested for acute radiation dermatitis (ARD) has proven to be better than any other, all achieving similar objective outcomes. No clear guidelines have therefore been established in clinics. Because the vehicle for such creams has shown to be an important factor in patient adherence to treatments in other dermatological diseases, patients’ opinions are evaluated.Material and methodsSeventy breast cancer patients referred for postoperative radiotherapy after conservative surgery were enrolled. Patients were assigned to use one of the 7 topical agents that are most-commonly used in the prevention of ARD. Patients’ reports were assessed using continuous visual analogue scales (VAS), objective signs and symptoms produced by ARD, and were rated using the RTOG and RISRAS scales.ResultsThe creams tested differed in their cosmetic properties significantly (p = 0.044). The performance of the agent, their absorption and any residue left over were also significantly different (p = 0.022, 0.014 and 0.02, respectively).ConclusionsTopical agents for preventive ARD are reported by patients to show different cosmetic properties. Cosmetic properties are important when choosing topical agents for ARD prevention. Recommending those with better cosmetic profiles would improve patient adherence to treatments.     

Analysis of the musculoskeletal loading of the thumb during pipetting – A pilot study

Previous epidemiological studies indicate that the use of thumb-push mechanical pipettes is associated with musculoskeletal disorders (MSDs) in the hand. The goal of the current study was to analyze the loading in the muscle–tendon units in the thumb during pipetting. The hand is modeled as a multi-body linkage system and includes four fingers (index, long, ring, and little finger), a thumb, and a palm segment. Since the current study is focused on the thumb, the model includes only nine muscles attached to the thumb via tendons. The time-histories of joint angles and push force at the pipette plunger during pipetting were determined experimentally and used as model input; whereas forces in the muscle–tendon units in the thumb were calculated via an inverse dynamic approach combined with an optimization procedure. Results indicate that all nine muscles have force outputs during pipetting, and the maximal force was in the abductor pollicis brevis (APB). The ratio of the mean peak muscle force to the mean peak push force during the dispensing cycle was approximately 2.3, which is comparable to values observed in grasping tasks in the literature. The analysis method and results in the current study provide a mechanistic understanding of MSD risk factors associated with pipetting, and may be useful in guiding ergonomic designs for manual pipettes.     

Structure–activity relationships of N-substituted ligands for the α7 nicotinic acetylcholine receptor

A series of α7 neuronal nicotinic acetylcholine receptor ligands were designed based on a structural combination of a potent, but non-selective ligand, epibatidine, with a selective lead structure, 2. Three series of compounds in which aryl moieties were attached via a linker to different positions on the core structure were studied. A potent and functionally efficacious analog, (3aR,6aS)-2-(6-phenylpyridazin-3-yl)-5-(pyridin-3-ylmethyl)octahydropyrrolo[3,4-c]pyrrole (3a), was identified.     

Alzheimer’s Protective A2T Mutation Changes the Conformational Landscape of the Aβ1–42 Monomer Differently Than Does the A2V Mutation

The aggregation of amyloid-β (Aβ) peptides plays a crucial role in the etiology of Alzheimer’s disease (AD). Recently, it has been reported that an A2T mutation in Aβ can protect against AD. Interestingly, a nonpolar A2V mutation also has been found to offer protection against AD in the heterozygous state, although it causes early-onset AD in homozygous carriers. Since the conformational landscape of the Aβ monomer is known to directly contribute to the early-stage aggregation mechanism, it is important to characterize the effects of the A2T and A2V mutations on Aβ_1–42 monomer structure. Here, we have performed extensive atomistic replica-exchange molecular dynamics simulations of the solvated wild-type (WT), A2V, and A2T Aβ_1–42 monomers. Our simulations reveal that although all three variants remain as collapsed coils in solution, there exist significant structural differences among them at shorter timescales. A2V exhibits an enhanced double-hairpin population in comparison to the WT, similar to those reported in toxic WT Aβ_1–42 oligomers. Such double-hairpin formation is caused by hydrophobic clustering between the N-terminus and the central and C-terminal hydrophobic patches. In contrast, the A2T mutation causes the N-terminus to engage in unusual electrostatic interactions with distant residues, such as K16 and E22, resulting in a unique population comprising only the C-terminal hairpin. These findings imply that a single A2X (where X = V or T) mutation in the primarily disordered N-terminus of the Aβ_1–42 monomer can dramatically alter the β-hairpin population and switch the equilibrium toward alternative structures. The atomistically detailed, comparative view of the structural landscapes of A2V and A2T variant monomers obtained in this study can enhance our understanding of the mechanistic differences in their early-stage aggregation.     

A thermodynamical study of the clockwork hypothesis proposed by E. Schrödinger

In the present study, the 'clockwork' hypothesis proposed by Schr?dinger was examined from the viewpoint of thermodynamics. Firstly, noticing a unidirectional transfer of entropy in a heat engine, the logic was briefly explained about a close relation between this entropy transfer and an irreversible cycle performed by a working body. Next, paying attention to two fundamental differences between a heat engine and a biological system, we considered an isolated system Asigma consisting of three one-component systems (Ai, A, Ao) and noted a case that the same molecules as the component ones flowed quasistatically into Ai from the outside. Then, the unidirectional flows of the molecules, energy and entropy, which were induced by the above inflow in Asigma, were formulated on the basis of the equilibrium thermodynamics for an open system. Furthermore, it was clarified that the fundamental equation for these flows is the Schr?dinger inequality and that the necessary-sufficient condition for this inequality is the existence of an irreversible cycle performed by A. Here A corresponds to a working body in a heat engine. It was, thus, concluded that the 'clockwork' hypothesis by Schr?dinger is considered to be reasonable for a biological system composed of various irreversible subsystems.     

Electrophoretic protein analysis for the identification of doubled haploid 1A–1R, 1B–1R wheat-rye double translocation lines and for the assessment of their genetic stability

Eighteen available doubled haploid wheat lines with a cytologically proven 1A–1R, 1B–1R double translocation, which where derived via anther culture from four crosses of the 1A–1R wheat-rye translocation cv Amigo with several 1B–1R wheat-rye translocation forms, were subjected to electrophoretic seed protein analysis. Besides, the five parents used in the crosses and some other wheat cultivars and doubled haploid lines (19 with a 1B–1R single translocation, 10 with a 1A–1R translocation and 7 without any 1R translocation) were also included in the investigation. It was found that the gliadin patterns visualized after SDS polyacrylamide gel electrophoresis of alcohol-soluble seed protein extracts can differentiate not only 1B–1R and 1A–1R translocation forms from wheats without any 1R-translocation chromosome, but also 1B–1R and 1A–1R wheats from each other. Moreover, 1A–1R, 1B–1R double translocation lines can be distinguished as well due to characteristic differences revealed between 1A–1R and 1B–1R translocation forms. Thus, all of tested dh₁- and dh₂-grains of the double translocation lines showed the expected doublet: the 1A–1R translocation (Amigo)-typical rye band and the 1B–1R translocation (Kawkas)-typical rye band. Consequently, gliadin patterns estimated after SDS electrophoresis may be used as markers for the fast detection of the desired 1A–1R, 1B–1R double translocation forms among 1A–1R single translocation lines, 1B–1R single translocation lines and lines without any 1R-translocation in the progenies of appropriate crosses. Furthermore, by means of gliadin tests on the dh₂-generation the excellent stability of the double translocation 1A–1R, 1B–1R during more than one propagation phase has been proven. Estimations of high-molecular weight (HMW) glutenin subunits coded by 1A and 1B chromosomes are compatible with the double translocation constitution. A few deviating results can be explained by crossing-over events. Seed protein analysis revealed that it is possible to produce 1A–1R, 1B–1R double translocation lines with good glutenin compositions provided that adequate favourable parents are used.Former name: Department of Physiology of Institute for Cereal Research     

Immunohistochemical localization of the angiotensin-(1–7) receptor Mas in the murine forebrain

Apart from the well-known biologically active angiotensin II, other biologically active angiotensins have been discovered, including angiotensin IV and angiotensin-(1–7). Some years ago, we and others discovered that the Mas proto-oncogene encodes a receptor that is essential for angiotensin-(1–7) signaling. Angiotensin-(1–7) is not only expressed in the periphery but also within the brain. Based on that, we examined the distribution of Mas within the murine brain, using an antibody directed against the 3^rd cytoplasmic loop of the receptor protein. Strongest Mas protein expression was detected in the dentate gyrus of the hippocampus and within the piriform cortex. However, Mas protein expression is not restricted to these areas, since Mas immunopositive neurons were also seen in different parts of the cortex, hippocampus, amygdala, basal ganglia, thalamus and hypothalamus. Based on the expression of Mas protein in the cortex and the limbic system, angiotensin-(1–7) signaling may play a role in synaptic plasticity, learning, memory and emotion, as has been described for angiotensin II and IV.     

A simple fluid–structure coupling algorithm for the study of the anastomotic mechanics of vascular grafts

Vascular anastomoses constitute a main factor in poor graft performance due to mismatches in distensibility between the host artery and the graft. This work aims at computational fluid–structure investigations of proximal and distal anastomoses of vein grafts and synthetic grafts. Finite element and finite volume models were developed and coupled with a user-defined algorithm. Emphasis was placed on the simplicity of the coupling algorithm. An artery and vein graft showed a larger dilation mismatch than an artery and synthetic graft. The vein graft distended nearly twice as much as the artery while the synthetic graft displayed only approximately half the arterial dilation. For the vein graft, luminal mismatching was aggravated by development of an anastomotic pseudo-stenosis. While this study focused on end-to-end anastomoses as a vehicle for developing the coupling algorithm, it may serve as useful point of departure for further investigations such as other anastomotic configurations, refined modelling of sutures and fully transient behaviour.     

Structure–activity relationship study of tachykinin peptides for the development of novel neurokinin-3 receptor selective agonists

Neurokinin B (NKB) is a potential regulator of pulsatile gonadotropin-releasing hormone (GnRH) secretion via activation of the neurokinin-3 receptor (NK3R). NKB with the consensus sequence of the tachykinin peptide family also binds to other tachykinin receptors [neurokinin-1 receptor (NK1R) and neurokinin-2 receptor (NK2R)] with low selectivity. In order to identify the structural requirements for the development of novel potent and selective NK3R agonists, a structure–activity relationship (SAR) study of [MePhe⁷]-NKB and other naturally occurring tachykinin peptides was performed. The substitutions to naturally occurring tachykinins with Asp and MePhe improved the receptor binding and agonistic activity for NK3R. The corresponding substitutions to NKB provided an NK3R selective analog.     

A time-resolved fluorescence resonance energy transfer assay suitable for high-throughput screening for inhibitors of immunoglobulin E–receptor interactions

The interaction of immunoglobulin E (IgE) antibodies with the high-affinity receptor, FcεRI, plays a central role in initiating most allergic reactions. The IgE–receptor interaction has been targeted for treatment of allergic diseases, and many high-affinity macromolecular inhibitors have been identified. Small molecule inhibitors would offer significant advantages over current anti-IgE treatment, but no candidate compounds have been identified and fully validated. Here, we report the development of a time-resolved fluorescence resonance energy transfer (TR–FRET) assay for monitoring the IgE–receptor interaction. The TR–FRET assay measures an increase in fluorescence intensity as a donor lanthanide fluorophore is recruited into complexes of site-specific Alexa Fluor 488-labeled IgE-Fc and His-tagged FcεRIα proteins. The assay can readily monitor classic competitive inhibitors that bind either IgE-Fc or FcεRIα in equilibrium competition binding experiments. Furthermore, the TR–FRET assay can also be used to follow the kinetics of IgE-Fc–FcεRIα dissociation and identify inhibitory ligands that accelerate the dissociation of preformed complexes, as demonstrated for an engineered DARPin (designed ankyrin repeat protein) inhibitor. The TR–FRET assay is suitable for high-throughput screening (HTS), as shown by performing a pilot screen of the National Institutes of Health (NIH) Clinical Collection Library in a 384-well plate format.     

Single-channel study of the binding-gating coupling in the slowly desensitizing chimeric α7-5HT3A receptor

We have studied the role of the highly conserved residue αLysine145 in the early steps of activation by acetylcholine of the nicotinic acetylcholine receptor (nAChR). Both macroscopic and single-channel currents were recorded in the slowly desensitizing chimeric mutant receptor α7V201-5HT3A/R432Q/R436D/R440A, made of α7 nAChRs and serotonin receptors of subtype 3A (ch1), and its corresponding mutant K145A (ch1/K145A) expressed in Xenopus oocytes. Mutant ch1/K145A receptors had a reduced gating function similar to that produced by the same mutation in the wild type receptor α7. The mutated receptor has reduced opening rate constants, β, and increased closing rate constants, α.     

Experimental simulation of the environment of the δ opioid receptor. A 500 MHz study of enkephalins in CDCl3

Complexes of [Met⁵] and [Leu⁵]enkephalin amides with 18-crown-6-ether have been studied in CDCl₃ solution by means of 500 MHz NMR spectroscopy, in order to simulate two of the features of the opioid receptor: the apolar environment and the binding of the charged N atom. Contrary to all previus studies in polar solvents the NH resonances are spread in a huge range (ca. 4 ppm) as in the spectra of rigid cyclic peptides. The two observed intramolecular hydrogen bonds are consistent with the existence of a single, folded, conformation, i.e. a C₁₀β-turn in which the Phe⁴ NH is linked to the Tyr¹ CO group.     

Crucial role for the LSP1–myosin1e bimolecular complex in the regulation of Fcγ receptor–driven phagocytosis

Actin cytoskeleton remodeling is fundamental for Fcγ receptor–driven phagocytosis. In this study, we find that the leukocyte-specific protein 1 (LSP1) localizes to nascent phagocytic cups during Fcγ receptor–mediated phagocytosis, where it displays the same spatial and temporal distribution as the actin cytoskeleton. Down-regulation of LSP1 severely reduces the phagocytic activity of macrophages, clearly demonstrating a crucial role for this protein in Fcγ receptor–mediated phagocytosis. We also find that LSP1 binds to the class I molecular motor myosin1e. LSP1 interacts with the SH3 domain of myosin1e, and the localization and dynamics of both proteins in nascent phagocytic cups mirror those of actin. Furthermore, inhibition of LSP1–myosin1e and LSP1–actin interactions profoundly impairs pseudopodial formation around opsonized targets and their subsequent internalization. Thus the LSP1–myosin1e bimolecular complex plays a pivotal role in the regulation of actin cytoskeleton remodeling during Fcγ receptor–driven phagocytosis.     

Quo vadis G protein-coupled receptor ligands? A tool for analysis of the emergence of new groups of compounds over time

Exponential growth in the number of compounds with experimentally verified activity towards particular target has led to the emergence of various databases gathering data on biological activity. In this study, the ligands of family A of the G Protein-Coupled Receptors that are collected in the ChEMBL database were examined, and special attention was given to serotonin receptors. Sets of compounds were examined in terms of their appearance over time, they were mapped to the chemical space of drugs deposited in DrugBank, and the emergence of structurally new clusters of compounds was indicated. In addition, a tool for detailed analysis of the obtained visualizations was prepared and made available online at http://chem.gmum.net/vischem, which enables the investigation of chemical structures while referring to particular data points depicted in the figures and changes in compounds datasets over time.     

A study of the nature of the immediate precursor of the extracellular α-amylase of Bacillus amyloliquefaciens. A reappraisal

1. A defined medium was devised for use in washed-cell experiments with post-exponential-phase cultures of Bacillus amyloliquefaciens. The medium allowed alpha-amylase to be secreted, bacterial concentration to increase and l-[U-(14)C]valine to be incorporated into protein at a linear rate, which was the same as in a post-exponential-phase culture, for up to 6h. 2. Determination of the specific radioactivity of l-[U-(14)C]valine in the medium, the intracellular amino acid pool, the cellular protein and the isolated alpha-amylase, after a 3h incubation of washed cells in the defined medium, showed that at least 76% of the alpha-amylase secreted was synthesized de novo. 3. By isolating the alpha-amylase formed during a 6h incubation in the presence of l-[U-(14)C]valine it was shown that the specific radioactivity of the N-terminal valine, within the limits of experimental error, was the same as that of the total valine residues from the complete alpha-amylase molecule. 4. A consideration of these results in relation to the whole literature on the subject strongly supports the idea that there is no reason to suppose that extracellular alpha-amylase is formed from a high-molecular-weight precursor in B. amyloliquefaciens and closely related organisms with identical characteristics of exoenzyme secretion.     

A case–control study on the effects of the apolipoprotein E genotypes in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has reached epidemic proportions being the most common cause of chronic liver disease in Western countries. The Apolipoprotein E (ApoE) gene has three major isoforms encoded by the ε2, ε3, and ε4 alleles, with the ε4 allele associated with hypercholesterolemia and the ε2 allele with the opposite effect. The role of apoE genotypes on NAFLD has been previously investigated with conflicting results. Our hospital-based case-control study conducted in Italy aims to explore the effect of the apoE genotypes on NAFLD risk and their effect on the clinical features of NAFLD patients. 310 NAFLD cases and 422 controls were genotyped for apoE. Adjusted odds ratios (ORs) and 95% confidence intervals (CI) from logistic regression were used to explore the relationship between NAFLD and apoE genotypes, as well as their interaction with selected demographic and lifestyle factors. ApoE ε4 allele carriers showed a statistically significant two-fold reduction of NAFLD risk (OR = 0.51, 95% CI: 0.28-0.93) compared with ε3 homozygotes. A statistically significant lower HDL cholesterol level was observed for ApoE ε4 carriers if compared with ε3/ε3 genotype or ApoE ε2 carriers with a nearly linear decreasing trend from ApoE ε2 to ApoE ε4 carriers. Our study reports for the first time a protective effect of the ε4 allele towards NAFLD that might be attributable to its role in the regulation of hepatic triglycerides rich very low-density lipoproteins secretion.     

Contribution of charged and polar residues for the formation of the E1–E2 heterodimer from Hepatitis C Virus

The transmembrane domains of the envelope glycoprotein E1 and E2 have crucial multifunctional roles in the biogenesis of hepatitis C virus. We have performed molecular dynamics simulations to investigate a structural model of the transmembrane segments of the E1–E2 heterodimer. The simulations support the key role of the Lys370–Asp728 ion pair for mediating the E1–E2 heterodimerization. In comparison to these two residues, the simulation results also reveal the differential effect of the conserved Arg730 residue that has been observed in experimental studies. Furthermore, we discovered the formation of inter-helical hydrogen bonds via Asn367 that stabilize dimer formation. Simulations of single and double mutants further demonstrate the importance of the ion-pair and polar interactions between the interacting helix monomers. The conformation of the E1 fragment in the simulation of the E1–E2 heterodimer is in close agreement with an NMR structure of the E1 transmembrane segment. The proposed model of the E1–E2 heterodimer supports the postulated cooperative insertion of both helices by the translocon complex into the bilayer.     

Systems for the detection and analysis of protein–protein interactions

The analysis of protein–protein interactions is important for developing a better understanding of the functional annotations of proteins that are involved in various biochemical reactions in vivo. The discovery that a protein with an unknown function binds to a protein with a known function could provide a significant clue to the cellular pathway concerning the unknown protein. Therefore, information on protein–protein interactions obtained by the comprehensive analysis of all gene products is available for the construction of interactive networks consisting of individual protein–protein interactions, which, in turn, permit elaborate biological phenomena to be understood. Systems for detecting protein–protein interactions in vitro and in vivo have been developed, and have been modified to compensate for limitations. Using these novel approaches, comprehensive and reliable information on protein–protein interactions can be determined. Systems that permit this to be achieved are described in this review.K. Kuroda, M. Kato and J. Mima contributed equally to this work.