Positive and Negative Expectations of Hopelessness as Longitudinal Predictors of Depression, Suicidal Ideation, and Suicidal Behavior in High‐Risk Adolescents

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136513/1/sltb12273.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136513/2/sltb12273_am.pd

Cryptosporidium parvum, a potential cause of colic adenocarcinoma

<p>Abstract</p> <p>Background</p> <p>Cryptosporidiosis represents a major public health problem. This infection has been reported worldwide as a frequent cause of diarrhoea. Particularly, it remains a clinically significant opportunistic infection among immunocompromised patients, causing potentially life-threatening diarrhoea in HIV-infected persons. However, the understanding about different aspects of this infection such as invasion, transmission and pathogenesis is problematic. Additionally, it has been difficult to find suitable animal models for propagation of this parasite. Efforts are needed to develop reproducible animal models allowing both the routine passage of different species and approaching unclear aspects of <it>Cryptosporidium </it>infection, especially in the pathophysiology field.</p> <p>Results</p> <p>We developed a model using adult severe combined immunodeficiency (SCID) mice inoculated with <it>Cryptosporidium parvum </it>or <it>Cryptosporidium muris </it>while treated or not with Dexamethasone (Dex) in order to investigate divergences in prepatent period, oocyst shedding or clinical and histopathological manifestations. <it>C. muris</it>-infected mice showed high levels of oocysts excretion, whatever the chemical immunosuppression status. Pre-patent periods were 11 days and 9.7 days in average in Dex treated and untreated mice, respectively. Parasite infection was restricted to the stomach, and had a clear preferential colonization for fundic area in both groups. Among <it>C. parvum</it>-infected mice, Dex-treated SCID mice became chronic shedders with a prepatent period of 6.2 days in average. <it>C. parvum</it>-inoculated mice treated with Dex developed glandular cystic polyps with areas of intraepithelial neoplasia, and also with the presence of intramucosal adenocarcinoma.</p> <p>Conclusion</p> <p>For the first time <it>C. parvum </it>is associated with the formation of polyps and adenocarcinoma lesions in the gut of Dex-treated SCID mice. Additionally, we have developed a model to compare chronic <it>muris </it>and <it>parvum </it>cryptosporidiosis using SCID mice treated with corticoids. This reproducible model has facilitated the evaluation of clinical signs, oocyst shedding, location of the infection, pathogenicity, and histopathological changes in the gastrointestinal tract, indicating divergent effects of Dex according to <it>Cryptosporidium </it>species causing infection.</p

HIV-1 Tat and AIDS-associated cancer: targeting the cellular anti-cancer barrier?

The acquired immunodeficiency syndrome (AIDS) is accompanied by a significant increase in the incidence of neoplasms. Several causative agents have been proposed for this phenomenon. These include immunodeficiency and oncogenic DNA viruses and the HIV-1 protein Tat. Cancer in general is closely linked to genomic instability and DNA repair mechanisms. The latter maintains genomic stability and serves as a cellular anti-cancer barrier. Defects in DNA repair pathway are associated with carcinogenesis

A dynamic risk index for forest fires in the upper watershed of the Chama river

La presente investigación tiene como propósito el desarrollo de un índice de riesgo de incendios forestales dinámico para la cuenca alta del río Chama, ubicada en el estado Mérida - Venezuela, destinado para el uso del grupo de Bomberos Forestales de la universidad de Los Andes (ULA). Se descarta el enfoque clásico o tradicional para la construcción del índice, por requerir datos meteorológicos que no estaban disponibles en la frecuencia y calidad requerida. En su lugar, se calculan índices de estrés de vegetación, a partir de composiciones Modis Ndvi para períodos de 16 días. Estos índices se validan usando los datos de los incendios registrados por el grupo de Bomberos Forestales y por el producto Modis Active Fire. Los resultados obtenidos sugieren que el índice podría ser útil en la estimación del riesgo de incendios ya que el 73% de los incendios ocurridos en el período considerado fueron identificados en zonas de alto [email protected] objective of this research was the development of a dynamic forest fire risk index for the upper watershed of the Chama river in Mérida, Venezuela. The index would be used for the department of forest firefighters of universidad de Los Andes. A traditional meteorological index was dismissed for lack of suitable data. Instead an index was calculated taking into account Modis Ndvi compositions. The index was validated using data from Modis active fire and from the database of forest-fighters. Results indicated that the index developed may be useful in the estimation of risk since approximately 73% of the fires that occurred in the period were labeled in high risk areas

Observaciones en la hiperplasia mesenquimal placentaria con el microscopio electrónico de barrido

Material de una placenta de embarazo con diagn&oacute;stico de enfermedad mesenquimatosa placentaria, a las 27 semanas de gestaci&oacute;n y dolicocefalia fetal fue obtenido para ser procesado con las t&eacute;cnicas de microscopia electr&oacute;nica de barrido previo an&aacute;lisis macro ymicrosc&oacute;pico del mismo. El examen macrosc&oacute;pico mostr&oacute; placentomegalia, vellosidades troncales hidr&oacute;picas detama&ntilde;o entre 2 y 35 mm, placa cori&oacute;nica comprimida,hematoma retroplacentario, infartos, vasos fetales trombosados e inserci&oacute;n marginal del cord&oacute;n. El examen microsc&oacute;pico exhibi&oacute; invaginaciones de la superficie deun trofoblasto hipotr&oacute;fico, ocasionalmente hiperpl&aacute;sico aunque de forma ligera. Proliferaci&oacute;n de c&eacute;lulas en elestroma semejantes a miofibroblastos, vasos aneurismalesrodeados por regiones claras de edema, sin macr&oacute;fagos.Adem&aacute;s escasos brotes sincitiales, cambios degenerativos del trofoblasto, membrana basal perforada, vasosestromales con diferente calibre, regi&oacute;n cisternal limitadapor c&eacute;lulas semejantes a miofibroblastos. Esta nuevaimagen tridimensional de la hiperplasia mesenquimal contribuye con el diagn&oacute;stico posnatal de una malformaci&oacute;n vascular de origen mesod&eacute;rmico.Palabras clave: Hiperplasia mesenquimal placentaria; Microscopia electr&oacute;nica de barrido.SUMMARYMaterial of a placenta from pregnancy with diagnostic of placental mesenchymal dysplasia at 27 gestation&acute;sweek and fetal dolicocephaly was obtained to be processedby scanning electron microscopy previous macroscopic and microscopic analysis. The macroscopicanalysis showed placentomegaly, hydropic stem villi between2 and 35mm of size, chorionic plate compressedretroplacental hematoma, infarcts, thrombosed fetal vesselsand marginal insertion of umbilical cord. The microscopicanalysis exhibited invaginations of hypotrophictrophoblast ocassionally hyperplasic. Proliferation ofcells like to myofibroblast and aneurysmal vessels surroundingof clear stromal regions without macrophagues.Besides scanty syncitial sprouts, degenerative changes ofthe trophoblast, basal membrane fenestrated, stromal vessels with different diameters, cisternal region limitedby cells like to myofibroblasts. This new three-dimensionalvision of placental mesenchymal hyperplasia contributes with the morphologic post natal diagnostic ofthis vascular malformation of mesodermic origin.Key words: Placental mesenchymal hyperplasia.Scanning electron microscopy