Measuring Transcellular Interactions through Protein Aggregation in a Heterologous Cell System.

Protein interactions at cellular interfaces dictate a multitude of biological outcomes ranging from tissue development and cancer progression to synapse formation and maintenance. Many of these fundamental interactions occur in trans and are typically induced by heterophilic or homophilic interactions between cells expressing membrane anchored binding pairs. Elucidating how disease relevant mutations disrupt these fundamental protein interactions can provide insight into a myriad of cell biology fields. Many protein-protein interaction assays do not typically disambiguate between cis and trans interactions, which potentially leads to an overestimation of the extent of binding that is occurring in vivo and involve labor intensive purification of protein and/or specialized monitoring equipment. Here, we present an optimized simple protocol that allows for the observation and quantification of only trans interactions without the need for lengthy protein purifications or specialized equipment. The HEK cell aggregation assay involves the mixing of two independent populations of HEK cells, each expressing membrane-bound cognate ligands. After a short incubation period, samples are imaged and the resulting aggregates are quantified.

Recognition of cancer mutations in histone H3K36 by epigenetic writers and readers.

Histone posttranslational modifications control the organization and function of chromatin. In particular, methylation of lysine 36 in histone H3 (H3K36me) has been shown to mediate gene transcription, DNA repair, cell cycle regulation, and pre-mRNA splicing. Notably, mutations at or near this residue have been causally linked to the development of several human cancers. These observations have helped to illuminate the role of histones themselves in disease and to clarify the mechanisms by which they acquire oncogenic properties. This perspective focuses on recent advances in discovery and characterization of histone H3 mutations that impact H3K36 methylation. We also highlight findings that the common cancer-related substitution of H3K36 to methionine (H3K36M) disturbs functions of not only H3K36me-writing enzymes but also H3K36me-specific readers. The latter case suggests that the oncogenic effects could also be linked to the inability of readers to engage H3K36M.

Shared peptide binding of HLA Class I and II alleles associate with cutaneous nevirapine hypersensitivity and identify novel risk alleles.

Genes of the human leukocyte antigen (HLA) system encode cell-surface proteins involved in regulation of immune responses, and the way drugs interact with the HLA peptide binding groove is important in the immunopathogenesis of T-cell mediated drug hypersensitivity syndromes. Nevirapine (NVP), is an HIV-1 antiretroviral with treatment-limiting hypersensitivity reactions (HSRs) associated with multiple class I and II HLA alleles. Here we utilize a novel analytical approach to explore these multi-allelic associations by systematically examining HLA molecules for similarities in peptide binding specificities and binding pocket structure. We demonstrate that primary predisposition to cutaneous NVP HSR, seen across ancestral groups, can be attributed to a cluster of HLA-C alleles sharing a common binding groove F pocket with HLA-C*04:01. An independent association with a group of class II alleles which share the HLA-DRB1-P4 pocket is also observed. In contrast, NVP HSR protection is afforded by a cluster of HLA-B alleles defined by a characteristic peptide binding groove B pocket. The results suggest drug-specific interactions within the antigen binding cleft can be shared across HLA molecules with similar binding pockets. We thereby provide an explanation for multiple HLA associations with cutaneous NVP HSR and advance insight into its pathogenic mechanisms.

Manifestaciones imaginológicas de las malformaciones cavernosas del sistema nervioso central / Imaging Manifestations of Cavernous Malformations of the Central Nervous System

El propósito de esta revisión es resaltar la epidemiología, presentación clínica y características imaginológicas de las malformaciones cavernosas del sistema nervioso central, especialmente en sus diferentes localizaciones, con el objetivo de brindarle al radiólogo claves para el diagnóstico de esta patología potencialmente curable. De las bases de datos de nuestras instituciones recolectamos casos de malformaciones cavernosas. Las imágenes de TC, MR y angiografía fueron evaluadas, y el tamaño, la localización, las características imaginológicas y los hallazgos asociados fueron registrados. Adicionalmente, se revisó la literatura científica pertinente a este tema para proveer una manera práctica de hacer una aproximación diagnóstica de esta malformación. Las malformaciones cavernosas son lesiones vasculares congénitas compuestas por vasos sinusoidales que forman una masa compacta. Pueden ocurrir en cualquier sitio del encéfalo y de la médula espinal. Imaginológicamente pueden presentar ciertas características alarmantes que pueden simular otras patologías más agresivas e incluso malignas. El conocimiento de los hallazgos característicos según su localización es esencial para evitar tratamientos innecesarios. Las malformaciones cavernosas del SNC pueden presentar ciertos rasgos que se sobreponen con patologías más malignas. Complicaciones asociadas como son la hemorragia y el edema perilesional pueden afectar aún más el diagnóstico adecuado. Por esta razón, es indispensable que el radiólogo conozca el comportamiento imaginológico de estas lesiones.

The purpose of this revision is to highlight the demographics, clinical presentation, and imaging features of cavernous malformations (CA) of the central nervous system, especially in its different locations, with the purpose of providing the radiologist clues regarding the diagnosis of this potentially curable pathology. We collected cases of cavernous malformations from the databases at our institutions. CT, MR and angiographic studies were evaluated and lesion size, location, imaging characteristics, multiplicity, and associated findings were recorded. Additionally, the scientific literature pertinent to the subject was reviewed in a practical manner in order to provide a practical manner of making a diagnostic approach of this malformation. Cavernous malformations are congenital vascular lesions composed of sinusoid- type blood vessels that assemble into a compact mass. They may occur in any location in the brain and in the spinal cord. In terms of imaging, they may present certain alarming characteristics that may mimic more aggressive or malignant entities. Associated complications such as hemorrhage and perilesional edema may affect adequate diagnosis at an ever larger degree. For this reason, it is essential that the radiologist is familiar with the imaging behavior of these lesions.

Oxido nítrico en el Síndrome de Sjögren: posible participación en el bloqueo de la apoptosis linfocitaria

Objetivo: evaluar el papel del óxido nítrico (NO) en el síndrome de sjögren primario (SSp) y su relación con la apoptosis tisular en glándulas salivares menores (GSM). Métodos. Las GSM correspondieron a sialoadenitis focal propia del SSp, sialoadenitis crónica (SAC) y a GSM histológicamente normales. El progreso del SSp fue evaluado mediante el puntaje por focos inflamatorios en GSM. Los niveles salivares y séricos de nitrito (NO2) fueron medidos mediante la reacción de Griess. La expresión de la óxido nitrico sintetasa tipo 2 (NOS2) y de la cistatina C (Cis-C), un inhibidor fisiológico de proteasas, fue examinada en GSM por inmunohistoquímica, y analizada de manera semicuantitativa. La apoptosis tisular fue evaluada determinando la fragmentación del ADN mediante la incorporación de nucleótidos marcados. Resultados. Los niveles de NO2 en saliva fueron mayores en pacientes con SSp (n=17) que en controles sanos (n=17) (71.1ñ20.6 vs 3.7 uM, p=0.02), mientras que en suero fueron similares (22.3ñ3.8 vs 17ñ1.4 uM). En el infiltrado inflamatorio la expresión de NOs2 fue mayor en pacientes con SSp que con SAC (n=4) (94 por ciento vs 7 por ciento). La NOS2 fue observada también en células epiteliales canaliculares, células acinares y fibroblastos de pacientes (SSp y SAC), y de controles normales (n=5). En GSM de pacientes con SSp la expresión de NOS2 fue mayor en aquellas con focos inflamatorios <4(78 por ciento vs 17 por ciento, p=0.04) y con menor número de células apoptóticas en el inflitrado inflamatorio (0.6ñ0.2 vs 1.66ñ0.3, p=0.02). La expresión de Cls-C fue observada en los tres grupos estudiados, principalamente en células epiteliales canaliculares, en algunos plasmocitos y células acinares de pacientes con SSp. No se observó asociación entre la expresión de Cls-C y la apoptosis tisular. Conclusión. Este estudio confirma el aumento de la síntesis de NO en el SS primario, producido localmente en el sitio inflamatorio, principalamente durante las fases tempranas de la enfermedad, y sugiere su participación en el bloqueo de la apoptosis linfocitaria, la cual no es regulada por la Cis-C. el mecanismo de esta inhibición apoptótica podría estar asociada a la S-nitrosilación de caspasas

Activity of two different triazoles in a murine model of paracoccidioidomycosis

A new orally absorbable triazole (Schering 39304) with a long serum half-life in man (60 hours), was tried in a murine model of progressive paracoccidioidomycosis and compared with itraconazole, another triazole which has proven effective in this mycosis. Only 15 of the infected, untreated mice survived while 53 to 75 of the animals receiving itraconazole survived. Mice treated with Schering 39304 exhibited higher (86-100) survival rates. Statistically, the 5 mg/kg Sch 39304 was superior to the 50 mg/kg itraconazole dose. Lung cultures showed that 20 mg/kg/day of Sch achieved sterilization of the infectious foci. These results indicate that the new triazole will have a place in the treatment of paracoccidioidomycosis.

Poroma ecrino maligno / Malignant eccrine poroma

Se presenta el caso de un hombre de 47 anos a quien se le diagnostico un poroma ecrino maligno localizado en el dorso del pie derecho, con metastasis a region inguinal, pulmon, higado y sistema nervioso central, que le produjeron la muerte. Se discuten los hallazgos clinico e histopatologicos

We report on the case of a 47 year-old man with the diagnosis of malignant eccrine poroma, located on the right foot; he died from metastatic lesions affecting inguinal region, lungs, liver and central nervous system. Clinical and histopathologic findings are discussed .A review Is Included on sweat gland carcinomas.