Multilayers of fluorinated amphiphilic polyions for marine fouling prevention.

Sequential layer-by-layer (LbL) deposition of polyelectrolytes followed by chemical cross-linking was investigated as a method to fabricate functional amphiphilic surfaces for marine biofouling prevention applications. A novel polyanion, grafted with amphiphilic perfluoroalkyl polyethylene glycol (fPEG) side chains, was synthesized and subsequently used to introduce amphiphilic character to the LbL film. The structure of the polyanion was confirmed by FTIR and NMR. Amphiphilicity of the film assembly was demonstrated by both water and hexadecane static contact angles. XPS studies of the cross-linked and annealed amphiphilic LbL films revealed the increased concentration of fPEG content at the film interface. In antifouling assays, the amphiphilic LbL films effectively prevented the adhesion of the marine bacterium Pseudomonas (NCIMB 2021).

Biomimicking micropatterned surfaces and their effect on marine biofouling.

When synthetic materials are submerged in marine environments, dissolved matter and marine organisms attach to their surfaces by a process known as marine fouling. This phenomenon may lead to diminished material performance with detrimental consequences. Bioinspired surface patterning and chemical surface modifications present promising approaches to the design of novel functional surfaces that can prevent biofouling phenomena. In this study, we report the synergistic effects of surface patterns, inspired by the marine decapod crab Myomenippe hardwickii in combination with chemical surface modifications toward suppressing marine fouling. M. hardwickii is known to maintain a relatively clean carapace although the species occurs in biofouling communities of tropical shallow subtidal coastal waters. Following the surface analysis of selected specimens, we designed hierarchical surface microtopographies that replicate the critical features observed on the crustacean surface. The micropatterned surfaces were modified with zwitterionic polymer brushes or with layer-by-layer deposited polyelectrolyte multilayers to enhance their antifouling and/or fouling-release potential. Chemically modified and unmodified micropatterned surfaces were subjected to extensive fouling tests, including laboratory assays against barnacle settlement and algae adhesion, and field static immersion tests. The results show a statistically significant reduction in settlement on the micropatterned surfaces as well as a synergistic effect when the microtopographies are combined with grafted polymer chains.

Reef sponges of the genus Agelas (Porifera: Demospongiae) from the Greater Caribbean.

The genus Agelas comprises a group of tropical and subtropical reef sponges that contains large, long-lived, often brightly colored and conspicuous species, distributed throughout the tropica l western Atlantic, temperate northern Atlantic (Mediterranean Sea), and western and central Indo-Pacific Realms. Among tropical sponge genera, Agelas is one with similar species richness in the Greater Caribbean in comparison to the Indo Pacific. The presence of verticillated acanthostyle spicules and a fibroreticulate skeleton of spongin fibres cored and/or echinated by spicules characterize this group. Taxonomic identification relies on a combination of characters, where external morphology and color play a key role, owing to the paucity of microscopical characters. Thus, there is still a great deal of taxonomic confusion, even for the more common species. We carried out a detailed revision of Agelas species throughout the Greater Caribbean area using classic taxonomic tools. Samples and observations covered Colombia, Belize, Jamaica, the Bahamas, Barbados, Curaçao and Venezuela, and included type material from major museum collections. According to our results, the genus Agelas in the Caribbean has at least thirteen valid species, viz. Agelas sceptrum (Lamarck, 1815); A. dispar Duchassaing & Michelotti, 1864;  A. dilatata Duchassaing & Michelotti, 1864; A. clathrodes (Schmidt, 1870);  A. cervicornis (Schmidt, 1870); A. conifera (Schmidt, 1870); A. schmidti Wilson, 1902;   A. tubulata Lehnert & van Soest, 1996; A. wiedenmayeri Alcolado, 1984;  A. citrina Gotera & Alcolado, 1987; A. sventres Lehnert & van Soest, 1996; A. repens Lehnert & van Soest, 1998; and A. cerebrum Assmann et al., 2001. We found that variation of microscopic characteristics like skeleton arrangement, number of verticills and their spines, and spicule length and width, can be used as taxonomic tools, but only in a thorough comparison with other species in the same sub-regional context. Thus, a certain degree of familiarity with the genus' regional variation is often required. The richness and distribution of these species in the Caribbean area show north/south differences and other ecological patterns are evident. 

Differential Regulation of the EGFR/PI3K/AKT/PTEN Pathway between Low- and High-Grade Gliomas.

Gliomas represent 70% of all central system nervous tumors and are classified according to the degree of malignancy as low- or high-grade. The permanent activation of the EGFR/PI3K/AKT pathway by various genetic or post-translational alterations of EGFR, PI3KCA, and PTEN has been associated with increased proliferation and resistance to apoptosis. The present study aimed to analyze the molecular/genetic changes in the EGFR/PI3K/AKT/PTEN pathway between low-grade and high-grade gliomas in a sample of Colombian patients. A total of 30 samples were tested for PI3K and PTEN mutations, EGFR, PI3K, and AKT gene amplification, AKT, PI3K, BAX, Bcl2 expression levels, and phosphorylation of AKT and PTEN, EGFR and/or PI3K gene amplification was found in 50% of low-grade and 45% of high-grade ones. AKT amplification was found in 25% of the low-grade and 13.6% of the high-grade. The expression of PI3K, AKT, Bcl2, and BAX was increased particularly to a high degree. AKT phosphorylation was found in 66% of low-grade and 31.8% of high-grade. Increased phosphorylation of PTEN was found in 77% low-grade and 66% high-grade. Our results indicate that alterations in the EGFR/PI3K/AKT/PTEN pathway could be important in the initiation and malignant progression of this type of tumor.

Polyion multilayers with precise surface charge control for antifouling.

We report on a molecular fabrication approach to precisely control surface ζ potentials of polymeric thin layers constructed by electrostatic layer-by-layer (LbL) assembly methods. The protocol established allows us to achieve surface isoelectric points (IEP) in the pH range of 6-10. Poly(acrylic acid) (PAA, a weak polyanion) and poly(diallyldimethylammonium chloride) (PDADMAC, a strong polycation) were chosen to build up the bulk films. The weak polycation polyethylenimine (PEI) was applied as a top layer. A unique feature of this approach is that the chemical composition of the top layer is not affected by the manipulation of the ζ potential of the films. Surface charge tuning is achieved by controlling the degree of ionization of the weak polyelectrolytes at various pH values and subsequent manipulation of the amount of polyelectrolyte deposited in the penultimate and last layers, respectively. Following assembly and characterization, the films were used as candidates for antifouling surfaces. The fouling behavior of barnacle cyprids and bacteria on the LbL films with similar hydrophilicity and roughness but different surface charge densities were studied. We found that more cyprids of Amphibalanus amphitrite settled on the negatively charged LbL film compared to the neutral or positively charged LbL film. In bacterial adhesion tests employing Pseudomonas, Escherichia coli, and Staphylococcus aureus, more bacteria were observed on the positively charged LbL film compared with the neutral and negatively charged LbL films, possibly as a result of the negative potential of the bacterial cell wall. The procedures proposed allow one to adjust surface isoelectric points of LbL architectures to achieve optimal antifouling performance of a given material taking into account specific pH values of the environment and the character of the fouler.

Sulfobetaine-based polymer brushes in marine environment: is there an effect of the polymerizable group on the antifouling performance?

Three different zwitterionic polymer brush coatings for marine biofouling control were prepared by surface-initiated atom transfer radical polymerization (ATRP) of sulfobetaine-based monomers including methacrylamide (SBMAm), vinylbenzene (SBVB) and vinylimidazolium (SBVI). None of these brush systems have been assessed regarding marine antifouling performance. Antifouling tests performed indicate that surfaces featuring these three brush systems substantially reduce the adhesion of the marine microalgae, Amphora coffeaeformis, and the settlement of cyprid larvae of the barnacle, Amphibalanus amphitrite, in a similar way, displaying comparable performance. Thus, it appears that the chemical structure of the polymerizable group has no substantial influence on marine antifouling performance.

Arteriovenous malformation masking associated anaplastic ganglioglioma in an adolescent / Malformación arteriovenosa asociada enmascara un ganglioglioma anaplásico multifocal en un adolescente

Abstract Grade III anaplastic ganglioglioma is an aggressive, rare, and radiosensitive central nervous system (CNS) tumour. It is more common in males, with a ratio of 1.3 to 1. Its peak incidence is in the third decade of life. Only 10 cases were recorded in children in Colombia from 2000 to 2014, with a fatal outcome in spite of radiation therapy. This is a case of an adolescent, who began having headaches, with warning signs related to an arteriovenous malformation hindering the diagnosis of this rare tumour. This presented in its aggressive, multi-focus form. Knowledge of clinical manifestations of space-occupying intracranial lesions facilitates the assessment and treatment of affected children.

Resumen El ganglioglioma anaplásico grado III es un tumor del sistema nervioso central (SNC) agresivo, infrecuente y radiosensible. Afecta más a hombres en una relación 1,3 a 1. Su pico de incidencia se encuentra en la tercera década de la vida. Existen solo 10 casos registrados en niños en Colombia desde el 2000 al 2014, con desenlace fatal a pesar de la radioterapia. Se presenta un caso de un adolescente que debutó con cefalea con signos de alarma asociado a una malformación arteriovenosa que dificultó el diagnóstico de este raro tumor, cuya presentación fue la más agresiva: la forma multicéntrica. El conocer las manifestaciones clínicas de lesiones intracraneales ocupantes de espacio facilita la evaluación y tratamiento a los niños afectados.

Pituicitoma hipofisario, un hallazgo diagnóstico inusual: reporte de caso / Pituitary pituicytoma, finding of an unusual diagnosis: a case report

Los pituicitomas son tumores infrecuentes de la región selar y supraselar, originados de la neurohipófisis, que suelen ser confundidos con otros tumores al compartir características imaginológicas. Se reporta el caso de una mujer de 36 años de edad, con un pituicitoma en la región selar, que fue diagnosticado como un adenoma hipofisario debido a los hallazgos clínicos e imaginológicos preoperatorios y se realiza una revisión de la literatura.

The Pituicytomas are rare tumors of the sellar and suprasellar region originated of the neurohypophysis and are usually confused with other tumors when sharing imagining features. It is reported a case of a 36 years old woman with pituicytoma in the sellar region that was diagnosed as a pituitary adenoma due to the presurgical clinical and imaging findings and, it is revised the literature.

Enfermedad de Creutzfeldt-Jakob esporádica: estudio clínico, patológico y molecular de un caso / Sporadic Creutzfeldt-Jakob disease: Clinical, pathological and molecular study

Generalidades. Las encefalopatías espongiformes transmisibles son enfermedades neurodegenerativas ocasionadas por la acumulación anormal de una variante mal plegada de la proteína priónica, lo cual induce la formación de conglomerados proteicos resistentes a la degradación. Además, son responsables de la disfunción sináptica, daño neuronal y de la sintomatología clásica acompañante. Esta proteína de membrana es codificada por el exón 2 del gen PRNP, ubicado en el brazo corto del cromosoma 20 y parece estar involucrada en la trasmisión sináptica, la transducción de señales, la actividad antioxidante de la superoxidodismutasa, neuroplasticidad y sobrevida celular. Un polimorfismo en el codón 129 se asocia con una susceptibilidad diferencial a la enfermedad Creutzfeldt-Jakob esporádica. Objetivo. Estudio clínico, patológico y molecular de un caso de una mujer de 58 años con diagnóstico de enfermedad de Creutzfeldt- Jakob esporádica. Métodos y resultados. Se presenta el caso de una mujer en quien aparece un trastorno depresivo del afecto con demencia progresiva y sintomatología general. Al final de la enfermedad, el cuadro progresó a un déficit neurológico focalizado en el área visual. La RMN mostró hiperintensidades inespecíficas córtico-subcorticales en el núcleo estriado; en el EEG se encontró pérdida de ritmos de fondo, patrón de descargas periódicas generalizadas y complejos trifásicos; en la biopsia cerebral postmorten se evidenció pérdida severa de la población neuronal en todas las capas, vacuolas en el neuropil, en el soma neuronal y en la glía. El análisis de secuencia del gen PRNP, a partir de extracción de DNA de sangre periférica, identificó homocigosis para metionina en el codón 129. La paciente fallece a los 3 meses del inicio de la sintomatología. Conclusión. Por epidemiología, curso clínico y exámenes paraclínicos se confirma el diagnóstico de enfermedad de Creutzfeldt- Jakob esporádica. La determinación del genotipo para los polimorfismos de riesgo se convierte en una herramienta útil para complementar por medios moleculares el diagnóstico y para profundizar la comprensión de la fisiopatología de la enfermedad de Creutzfeldt-Jakob, tanto para formas esporádicas como para la nueva variante.

Background: Transmissible spongiform encephalopathies are neurodegenerative diseases caused by abnormal accumulation of pathogenic isoform the prion protein, which induces the formation of conglomerates protein resistant to degradation. They are also responsible for synaptic dysfunction, neuronal damage and the classic symptoms of disease. This membrane protein is encoded by exon 2 of the gene PRNP, located on the short arm of chromosome 20 and appears to be involved in synaptic transmission, signal transduction, the antioxidant activity of the superoxid dismutasa, neuroplasticity and cell survival. One polymorphism at codon 129 is associated with differential susceptibility to disease sporadic Creutzfeldt-Jakob disease. Aim: Clinical, pathological and molecular report on an 58 year-old woman with pathological diagnosis of Creutzfeldt-Jakob sporadic disease. Methods and results. The clinic course appears with a behavior depressive disorder with progressive dementia and symptoms. At the end of the disease, the scenario progressed to a neurological deficit focused on the visual area. The MRI showed nonspecific hyperintensity in cortiço-subcortical nucleus in the striatum, the EEG showed patterns of recurrent generalized discharges and complex three-phase, the brain biopsy post-morten showed severe loss of the neuronal population in all the layers, vacuoles in the neuropil, in the neuronal soma and the glial. The analysis of sequence of the gene PRNP identified homozygotes for methionine at codon 129. The patient died at 3 months of the onset of symptoms. Conclusions: Epidemiology, clinical course and paraclinical examinations confirmed the diagnosis of Creutzfeldt-Jakob sporadic. The genotyping for polymorphisms of risk becomes useful tool to complement through molecular diagnosis and to deepen the understanding of the pathophysiology of Creutzfeldt- Jakob disease, both for sporadic forms and for the new variant.

New records of the genus Agelas Duchassaing & Michelotti, 1864 (Porifera, Agelasida) off the Amazon River mouth, Brazil, Southwestern Atlantic / Novos registros do gênero Agelas Duchassaing & Michelotti, 1864 (Porifera, Agelasida) ao largo da desembocadura do Rio Amazonas, Brasil, Atlântico Sudoeste

This work provides new information on agelasid sponges found on the continental shelf off northern Brazil. Agelas sceptrum (Lamarck, 1815) and Agelas wiedenmayeri Alcolado, 1984 have their first record for the Brazilian coast. Agelas dispar Duchassaing & Michelotti, 1864 and Agelas schmidti Wilson, 1902, previously recorded from Brazil, are cited for the first time off the mouth of the Amazon River.

Este trabalho fornece novas informações sobre esponjas agelasidas encontradas na costa norte da plataforma continental brasileira. Agelas sceptrum (Lamarck, 1815) e Agelas wiedenmayeri Alcolado, 1984 têm seu primeiro registro para a costa brasileira. Agelas dispar Duchassaing & Michelotti, 1864 e Agelas schmidti Wilson, 1902, registradas anteriormente na costa brasileira, são citadas pela primeira vez ao largo da desembocadura do Rio Amazonas.

Histoplasmosis intestinal em el sindrome de inmunodeficiencia adquirida: presentacion de una caso, Hospital Simon Bolivar, Santa Fe de Bogota / Intestinal histoplasmosis in AIDS

La histoplasmosis intestinal en pacientes con síndrome de inmunodeficiencia adquirida es una entidad rara. Se han descrito pocos casos en la literatura. La mayoría de los pacientes presenta dolor abdominal, pérdida de peso, diarrea, fiebre y hemorragia de vías digestivas. Presentamos el caso de un paciente de sexo masculino, HIV positivo, que desarrolló histoplasmosis colónica y revisamos la literatura.

Oncocitoma hipofisiario: informe de un caso / Hypophyseal oncocytoma: report of a case

Los Oncocitomas Hipofisiarios son raros tumores que se presentan asemejando Adenomas no funcionantes de tipo eosinófilo y que ultraestructuralmente se caracterizan por la presencia en el citoplasma celular, de gran cantidad de mitocondrias polimorfas y de estructura atípica, que dan el aspecto a la microscopía de luz de células eosinófilas y de aspecto granular. Presentamos el caso de un paciente de 59 años, estudiado y tratado en el Instituto Neurológico de Colombia, por un adenoma no funcionante de hipófisis, que el estudio por microscopía electrónica presentó las características de un Oncocitoma Hipofisiario

Oligodendrogliomas / Oligodendrogliomas

En nuestra serie de 805 tumores cerebrais confirmados histológicamente de 1974 a 1984 encontramos 24 oligodendrogliomas, lo cual corresponde al 2,9% de todos los casos. De ellos había 13 hombres y 11 mujeres con edad prometido de 19 años para los hombres y 35 para las mujeres con rango entre 19 y 69 años. La mayor parte estaban localizados en el lóbulo frontal. La duración de los síntomas pre-operatorios osciló entre 1 día y 15 años. Los principales síntomas fueron convulsiones, cefalea y transtornos del comportamiento, cuando estas se asociaron con calcificaciones demostradas por rayos X símples o escanografía. En un enfermo de 30 a 50 años de edad el diagnóstico muy problemente es de oligodenglioma

Microcalcificación y meningioma

Se presenta el caso de un meningioma psamomatoso en un paciente adolescente con sus hallazgos clínicos, radiológicos y de patología. Su rar presentación en menores de 20 años y la buena correlación entre las imágenes y la patología lo califican como un caso representativo

Paragonimiasis pulmonar, cerebral y abdominal. Presentación de un caso de revisión de la enfermedad en Colombia / Pulmonary, cerebral and pelvic pargonimiasis. Prersentation of one case and review in Colombia

Presentamos el caso de un paciente con compromiso pulmonar, cerebral y pélvico cuyo estudio confirmó finalmente el diagnóstico de una paragonimiasis. Esta es una zoonosis (enfermedad del hombre y de los animales) causada por parásitos tremátodos del género paragonimus, que afecta pricipalmente el pulmón y otros órganos como el cerebro, el páncreas y el hígado. El parásito causante tiene un ciclo de vida que involucra moluscos y crustáceos como los cangrejos. Presenta una distribución geográfica particular en Asia y Sur América. Se había descrito desde hace muchos años en países vecinos a Colombia pero solamente en forma reciente se han publicado casos y series de casosnacionales con pacientes provenientes del Meta y de la comunidad Emberá. El caso que presentamo sirve de ilustración y de señal de alerta para considerar esta parasitosis en el diagnóstico diferencial de pacientes con enfermedad pulmonar, eosinofilia y procedencia de regiones como Chocó, Meta o Guaviare