Molecular Mediators of Acute and Chronic Itch in Mouse and Human Sensory Neurons

Itch is a distinct sensation that arises from the activation of small-diameter pruriceptive nerve fibers innervating the skin. Recent strides in the field have identified several histamine-dependent and -independent pruriceptive pathways and receptors that contribute to acute and chronic itch. The work presented in this thesis further investigates the molecular mechanisms involved in the signaling, development, and sensitization of itch in mouse and human. Most pruritogen receptors are Gq-Protein Coupled Receptors (GqPCR), which canonically activate protein kinase C (PKC); however, little is known about whether specific PKC isoforms regulate itch. The first study in this thesis demonstrates that the isoform PKCδ contributes to histamine-induced scratching, but not histamine-independent itch. Our studies show that PKCδ is expressed in dorsal root ganglia (DRG), where it mediates sensory neuron responses to histamine. To investigate the mechanisms behind a common form of chronic pruritus, the second study in this thesis applied a mouse model of dry skin itch to test changes in sensory neuron structure and function. We found that dry skin was marked by a significant increase in epidermal nerve fiber innervation independent of scratching. Furthermore, dry skin was associated with a selective increase in non-peptidergic, Ret-positive fibers and a functional expansion of the proportion of chloroquine-sensitive neurons. Epidermal hyperinnervation and increased growth factor levels in the skin of patients with pruritic skin diseases suggest a potential role for neurotrophic factors (NTFs) in itch. In our third study, we tested the hypothesis that NTF signaling modulates pruritogen-evoked itch. Pretreatment with nerve growth factor (NGF) selectively potentiated histamine-induced scratching and increased the proportion of histamine-responsive sensory neurons. Artemin pretreatment, on the other hand, potentiated scratching induced by chloroquine, and increased the proportion of chloroquine-responsive neurons. Interestingly, aberrations in endogenous TrkA-NGF signaling significantly impacted normal pain sensation, but did not play a role in histamine- and chloroquine-induced itch. In the final study of this thesis, we developed a protocol to surgically extract human DRG from organ donors and culture dissociated human primary sensory neurons. Using this approach, we performed functional studies to characterize the pruritogen- and algogen- responsive sensory neuron subpopulations in humans. We found that NGF and artemin pretreatment did not change histamine and chloroquine responses in vitro, indicating a potential functional difference between mouse and human sensory neurons

Promoting Learning and Achievement Through Self-Assessment

Criteria-referenced self-assessment is a process during which students collect information about their own performance or progress; compare it to explicitly stated criteria, goals, or standards; and revise accordingly. The authors argue that self-assessment must be a formative type of assessment, done on drafts of works in progress: It should not be a matter of determining one\u27s own grade. As such, the purposes of self-assessment are to identify areas of strength and weakness in one\u27s work in order to make improvements and promote learning. Criteria-referenced self-assessment has been shown to promote achievement. This article introduces criteria-referenced self-assessment, describes how it is done, and reviews some of the research on its benefits to students

Early Childhood Development: Features and Prevention of Disorders // Ранно детско развитие: особености и превенция на нарушенията

The complexity of the early childhood development process and its gradual transformation into an integrative object of care and research interest has been studied. The child is placed at the centre of social science, social theory and practice, and the family-oriented approach to the family (nuclear and extended) are adopted. This is evidenced by the analysis provided in the review of the rich heritage of research, theoretical works and practices with authors from around the world, and strategic and regulatory documents of global, European and national institutions. Adapted interdisciplinary tools and an author's questionnaire are used for the research. The implementation of qualitative and quantitative research establishes the importance of early childhood development in the parent community in Bulgaria and the resulting need for knowledge, practices, competencies and opportunities for the prevention of disorders. The study results formulate specific recommendations for health promotion and prevention in early childhood and increase parental competence.Проследява се сложността на процеса на ранно детско развитие и неговото постепенно превръщане в интегративен обект на грижи и изследователски интерес. Детето се поставя в центъра на обществознанието, на социалната теория и практика, а към семейството (нуклеарно и разширено) се приема семейно-ориентираният подход. Това се доказва чрез предоставения анализ в обзора на богато наследство от научни изследвания, теоретични трудове и практики с автори от целия свят, на стратегически и нормативни документи на световни, европейски и национални институции. За изследването се използват адаптирани интердисциплинарни инструменти и авторски въпросник. Чрез извършването на качествени и количествени изследвания се установява значимостта на ранното детско развитие в родителската общност в България и произтичащите от това потребности от знания, практики, компетенции и възможности за превенция на нарушенията. Резултатите от изследването се използват за формулирането на конкретни препоръки с цел промоция на здравето и профилактика в ранна детска възраст и за повишаване на родителската компетентност

Polybenzimidazole membranes for organic solvent nanofiltration: formation parameters and applications

Recently, organic solvent nanofiltration (OSN) became an attractive tool for molecular separation in organic feed streams. Although commercial polymeric membranes are available and easily accessible, they still face several issues in OSN conditions. For instance, commercial membranes usually have low discrimination between the target molecules and waste reagents, poor stability in organic solvents and acidic/basic conditions and inconsistent performance over service life time. The main objective of this research was to study the fabrication and function of polybenzimidazole (PBI) membranes for OSN in order to obtain a more versatile membrane than the available commercial ones. The stability of PBI membranes in harsh solvents and corrosive environments was achieved by chemically crosslinking the polymeric backbone. The chemical resistance of crosslinked PBI membranes was demonstrated by exposing the membranes to realistic conditions used in pharmaceutical and chemical separation processes, such as organic solvents containing acids or bases. Further, the crosslinking reaction itself was studied thoroughly by analysing the reaction mechanism and the effect of reaction parameters on membrane stability and performance. A better understanding of these parameters is crucial to the development of robust, reproducible and scalable membranes. The analysis was carried out using a statistical approach based on Design of Experiments (DoE) methodology, which enabled reduction of the number of experiments, to study more than one factor at a time and to identify the relevant parameters and their interactions. A phenomenological interpretation of the statistical models was also attempted. The investigation of the reaction mechanism revealed the formation of charged complexes in the PBI backbone that can be used to facilitate the transport of solutes carrying a charge opposite to that of the membrane’s surface. This was studied by filtration experiments through PBI membranes using charged and neutral solutes with similar molecular weights. The charge of crosslinked and uncrosslinked membranes was modified by applying different treatments to the membranes. It was found that the transport of solutes through PBI membranes was based on both size exclusion and ion exchange. Finally, the effect of the choice of co-solvent or non-solvent additive in the fabrication of PBI membranes was studied and it was found that different additives result in membranes with different properties. However, no correlation was found between the properties of the solvents and the performance of the membranes. In conclusion, the availability of such membranes could lead to a wider implementation of membrane units in many industries which require separation of molecules from organic solvents. This was demonstrated by applying crosslinked PBI membranes to OSN membrane cascades in which the problem of insufficient separation capability was addressed. Also, uncrosslinked PBI membranes were successfully molecularly imprinted and have been shown to have potential as size exclusion barriers and shape specific absorbents.Open Acces

Metabotropic glutamate receptor 2/3 (mGluR2/3) activation suppresses TRPV1 sensitization in mouse, but not human sensory neurons

AbstractThe use of human tissue to validate putative analgesic targets identified in rodents is a promising strategy for improving the historically poor translational record of preclinical pain research. We recently demonstrated that in mouse and human sensory neurons, agonists for metabotropic glutamate receptors 2 and 3 (mGluR2/3) reduce membrane hyperexcitability produced by the inflammatory mediator prostaglandin E2(PGE2). Previous rodent studies indicate that mGluR2/3 can also reduce peripheral sensitization by suppressing inflammation-induced sensitization of TRPV1. Whether this observation similarly translates to human sensory neurons has not yet been tested. We found that activation of mGluR2/3 with the agonist APDC suppressed PGE2-induced sensitization of TRPV1 in mouse, but not human, sensory neurons. We also evaluated sensory neuron expression of the gene transcripts for mGluR2 (Grm2), mGluR3 (Grm3), and TRPV1 (Trpv1). The majority ofTrpv1+mouse and human sensory neurons expressedGrm2and/orGrm3, and in both mice and humans,Grm2was expressed in a greater percentage of sensory neurons thanGrm3. Although we demonstrated a functional difference in the modulation of TRPV1 sensitization by mGluR2/3 activation between mouse and human, there were no species differences in the gene transcript colocalization of mGluR2 or mGluR3 with TRPV1 that might explain this functional difference. Taken together with our previous work, these results suggest that mGluR2/3 activation suppresses only some aspects of human sensory neuron sensitization caused by PGE2. These differences have implications for potential healthy human voluntary studies or clinical trials evaluating the analgesic efficacy of mGluR2/3 agonists or positive allosteric modulators.</jats:p

(Dis)honesty in the face of uncertain gains or losses

We examine dishonest behavior in the face of potential uncertain gains and losses in three pre-studies (N = 150, N = 225, N = 188) and a main study (N = 240). Ample research has shown that people cheat when presented with the opportunity. We use a die-under-cup paradigm, in which participants could dishonestly report a private die roll and thereby increase the odds to obtain a desired outcome. Results showed that the framing of the uncertain situation mattered: Participants who lied to decrease the likelihood to experience a loss used major lies (i.e., reporting a ‘6’), while those who lied to increase the chance to achieve an equivalent gain used more modest lies.Social decision makin

Liquid-phase synthesis of 2′-methyl-RNA on a homostar support through organic-solvent nanofiltration

Due to the discovery of RNAi, oligonucleotides (oligos) have re-emerged as a major pharmaceutical target that may soon be required in ton quantities. However, it is questionable whether solid-phase oligo synthesis (SPOS) methods can provide a scalable synthesis. Liquid-phase oligo synthesis (LPOS) is intrinsically scalable and amenable to standard industrial batch synthesis techniques. However, most reported LPOS strategies rely upon at least one precipitation per chain extension cycle to separate the growing oligonucleotide from reaction debris. Precipitation can be difficult to develop and control on an industrial scale and, because many precipitations would be required to prepare a therapeutic oligonucleotide, we contend that this approach is not viable for large-scale industrial preparation. We are developing an LPOS synthetic strategy for 2′-methyl RNA phosphorothioate that is more amenable to standard batch production techniques, using organic solvent nanofiltration (OSN) as the critical scalable separation technology. We report the first LPOS-OSN preparation of a 2′-Me RNA phosphorothioate 9-mer, using commercial phosphoramidite monomers, and monitoring all reactions by HPLC, (31)P NMR spectroscopy and MS