p-Methoxyphenol: A potent and effective scavenger for solid-phase peptide synthesis.

During the final step of t-Boc/Bzl, solid-phase peptide synthesis (SPPS)-protecting groups from amino acids (aa) side chains must be removed from the target peptides during cleavage from the solid support. These reaction steps involve hydrolysis with hydrogen fluoride (HF) in the presence of a nucleophile (scavenger), whose function is to trap the carbocations produced during SN 1-type reactions. Five peptide sequences were synthesised for evaluating p-methoxyphenol effectiveness as a potent scavenger. After the synthesis, the resin-peptide was then separated into two equal parts to be cleaved using two scavengers: conventional reactive p-cresol (reported in the literature as an effective acyl ion eliminator) and p-methoxyphenol (hypothesised as fulfilling the same functions as the routinely used scavenger). Detailed analysis of the electrostatic potential map (EPM) revealed similarities between these two nucleophiles, regarding net atomic charge, electron density distribution, and similar pKa values. Good scavenger efficacy was observed by chromatography and mass spectrometry results for the synthesised molecules, which revealed that p-methoxyphenol can be used as a potent scavenger during SPPS by t-Boc/Bzl strategy, as similar results were obtained using the conventional scavenger.

Specific Binding Peptides from Rv3632: A Strategy for Blocking Mycobacterium tuberculosis Entry to Target Cells?

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb, i.e., the aetiological agent); the WHO has established this disease as high priority due to its ensuing mortality. Mtb uses a range of mechanisms for preventing its elimination by an infected host; new, viable alternatives for blocking the host-pathogen interaction are thus sought constantly. This article updates our laboratory's systematic search for antigens using bioinformatics tools to clarify the Mtb H37Rv Rv3632 protein's topology and location. This article reports a C-terminal region consisting of peptides 39255 and 39256 (81Thr-Arg114) having high specific binding regarding two infection-related cell lines (A549 and U937); they inhibited mycobacterial entry to U937 cells in a concentration-dependent manner. Rv3632 forms part of the mycobacterial cell envelope, formed by six linear synthetic peptides. Circular dichroism enabled determining the protein's secondary structure. It was also found that peptide 39254 (61Gly-Thr83) was a HABP for alveolar epithelial cells and inhibited mycobacteria entry to these cells regardless of concentration. Sera from active or latent tuberculosis patients did not recognise HABPs 39254 and 39256. These sequences represent a promising approach aiming at their ongoing modification and for including them when designing a multi-epitope, anti-tuberculosis vaccine.

Diazepam Reduces Escape and Increases Closed-Arms Exploration in Gerbils After 5 min in the Elevated Plus-Maze.

Despite the wide implementation of the elevated plus-maze (EPM) test to assess anxiety-related behaviors in rodents, the interpretation of these measures in gerbils has received limited attention. Here, male gerbils were treated with vehicle or diazepam, followed by a 20-min EPM session. EPM data were subjected to minute-by-minute, 5-min bins and factor analyses. During the first 5-min, gerbils avoided the closed arms in favor of the open arms and diazepam increased open-arms entries; furthermore, a single factor (escape behavior) explained all the analyzed measures. Only after 5-min, gerbils reduced open-arms exploration and three independent factors emerged for each subsequent 5-min bin. These findings suggest that EPM data from gerbils should be analyzed in at least two 5-min bins. Measures from the standard 5-min session seem to be related to an escape response from the EPM through the open arms. Once habituated, measures from the second 5-min bin seem to be related to a conflictive situation: keep trying to escape unsuccessfully (due to open-arms height) or seek protection in the closed arms (unsafe places). Diazepam seems to reduce this conflict by mitigating the escape response (Factor 1 - Anxiety) and increasing closed-arms approach (Factor 2) and risk assessment (Factor 3). Unlike mice and rats, a decrease in open-arms exploration and an increase in risk assessment could be interpreted as an anxiolytic-like effect in gerbils.

Critical role of HLA-DRß* binding peptides' peripheral flanking residues in fully-protective malaria vaccine development.

A vaccine candidate component must fit perfectly into the antigen presenting HLA-DRß* molecule's groove (or canonical nonapeptide) peptide binding region (PBR) during antigen presentation to the T-cell receptor (TCR), conforming a specific and stable macromolecular complex and induce an appropriate immune response. Antigen's peripheral flanking residues (PFR, positions (p) -p2 and p10) must thus establish strong interactions with the HLA-DRß* - TCR complex. These amino acids (aa) have specific physico-chemical characteristics enabling differentiation between non-protective but antibody-inducer (NPAI), short-lived protection inducer (SLPI) and long-lasting protection inducer (LLPI) peptides when used as an antimalarial vaccine component. Their identification (through 1H-NMR and Aotus monkey immunization) and proper modification contributes to a logical and rational methodology for long-lasting and protective immunological memory.

Alargamiento conjunto del flexor hallucis longus y del flexor digitorum longus en el tratamiento quirúrgico del pie equino varo congénito: una técnica de tenodesis / Lengthening and tenodesis of flexor hallucis longus and flexor digitorum longus in clubfoot surgical treatment

Introducción: el pie equino varo congénito (PEVC) ha sido un severo trastorno ortopédico del paciente recién nacido y lactante. El estándar de oro en su tratamiento es el método de Ponseti; sin embargo, cuando es necesario realizar un tratamiento quirúrgico de esta patología se ha empleado la liberación posteromedial ampliada. Este artículo muestra los resultados de la utilización de una modificación de esta técnica, en la cual se realiza un alargamiento conjunto del flexor hallucis longus y del flexor digitorum longus. Materiales y métodos: se diseñó una serie de casos de los pacientes con PEVC que requirieron tratamiento quirúrgico con la técnica propuesta, entre 1995 y 2002, en el Hospital Universitario San Jorge de Pereira. Se midió la capacidad de flexión activa eficiente de los dedos del pie y el patrón de marcha en un periodo mínimo de seguimiento de 2 años. Resultados: se incluyeron 30 pacientes, la mitad con deformidad bilateral. La edad al momento de la intervención fue de menos de un año en el 80% de los pacientes. El tiempo de seguimiento promedio fue de 5 años. Se encontró una buena fuerza y un uso balanceado y funcional de los flexores durante la marcha en todos los pacientes. Discusión: los tendones del flexor hallucis longus y del flexor digitorum longus son pequeños y su alargamiento individual muy dispendioso, dejando grandes superficies cruentas para cicatrización y fibrosis en el trayecto de trabajo. Con esta técnica se logran zonas de deslizamiento que permiten el sinergismo de los tendones y aseguran su buena función, por lo que se recomienda su uso en el procedimiento de liberación posteromedial.