Mortality after deferral of treatment or no treatment for choroidal melanoma

Purpose: To report mortality of patients who were eligible for enrollment in the Collaborative Ocular Melanoma Study (COMS) clinical trials of medium-sized choroidal melanoma or large-sized choroidal melanoma but chose to defer treatment or receive no melanoma treatment. Design: Prospective nonrandomized multicenter cohort study as an adjunct to COMS randomized clinical trials. Methods: Patient follow-up procedures included examinations, correspondence, telephone contacts, and National Death Index searches. Primary outcome was patient death measured by all-cause mortality. Secondary outcomes were melanoma treatment and melanoma metastasis. Results: Of 77 patients eligible for COMS clinical trials who chose to defer or receive no melanoma treatment, 61 were appropriate candidates and 45 (74%) enrolled in the natural history study (NHS). In all, 42 patients (42 eyes) had medium melanoma, and the median follow-up was 5.3 years (range, 4–10.7 years). In all, 22 patients (52%) had subsequent melanoma treatment, and 20 (48%) had no melanoma treatment. For the 42 patients, Kaplan–Meier estimate of 5-year mortality was approximately 30% [95% confidence interval (CI), 18%–47%]. For COMS medium melanoma trial, 5-year mortality was 18% (95% CI, 16%–20%), not statistically significantly different from the NHS patients. After adjusting for differences in age and longest basal diameter, the 5-year risk of death for NHS patients versus COMS trial patients was 1.54 (95% CI, 0.93–2.56). Three patients had large melanoma. Melanoma metastasis was confirmed or suspected in 8 (42%) of 19 deaths. Conclusion: Greater mortality and higher risk of death for NHS patients are probative but not conclusive evidence of a beneficial, life-extending effect of medium melanoma treatment.

Seroprevalence and risk factors for Neospora caninum in small dairy farms in central Chile / Seroprevalencia y factores de riesgo de Neospora caninum en pequeñas granjas lecheras de la zona central de Chile

ABSTRACT Objective. To provide information about seroprevalence and risk factors of Neospora caninum infection in bovines of central Chile. Material and Methods. The study population are small dairy farms that are part of a Government Technical Support Service (SAT) in the O´Higgins region in central Chile. Sera samples were collected from milking cows and analyzed by a commercial ELISA kit. Additionally, a questionnaire was applied to farmers to identify risk factors through logistic regression. Results. The farm level prevalence was found to be 67%, and within farms seroprevalence 55%. Abortion history (p= 0.037, OR=5.09), dogs feed source (p= 0.0429, OR=6), cattle drinking water source (p=0.034, OR=4.5) and abortions management (p=0.017, OR=7.43) were found as significant risk factors for infection. Conclusion. There is a high N. caninum seroprevalence in small SAT´s dairy farms in O´Higgins region. These results highlight the need of improving N. caninum surveillance, and the development of preventive measures to avoid losses related with this disease.

RESUMEN Objetivos. Proveer información sobre la seroprevalencia y factores de riesgo asociados a la infección por Neospora caninum en bovinos en Chile central. Materiales y métodos. La población estudiada corresponde a pequeñas lecherías que son parte de un programa gubernamental de Asistencia Técnica (SAT), en la región de O´Higgins en Chile central. Muestras de suero fueron recolectadas desde vacas en lactancia y analizadas mediante un kit comercial ELISA. Además, se aplicó un cuestionario a los dueños de los animales para la identificación de factores de riesgo a través de regresión logística. Resultados. Se identificó una prevalencia a nivel de granja del 67%, mientras que dentro de las granjas positivas, esta fue en promedio de 55%. El historial de abortos (p= 0.037, OR=5.09), la fuente de alimentación de perros (p= 0.0429, OR=6), la fuente de agua de bebida de las vacas (p=0.034, OR=4.5) y el manejo de los abortos (p=0.017, OR=7.43) fueron identificados como factores de riesgo para la infección. Conclusiones. Se observa una alta seroprevalencia de N. caninum en pequeños productores lecheros pertenecientes al SAT en Chile central. Los resultados presentados resaltan la necesidad de mejorar las acciones de vigilancia de esta enfermedad y el desarrollo de medidas preventivas para evitar las pérdidas asociadas a esta enfermedad.

Epidemiología clínica y molecular de las infecciones por Shigella spp en niños de la Región Metropolitana durante el verano 2004-2005 / Shigella spp Infections In children living In the Metropolitan RegionChile, during summer of 2004-2005

Background: Shigella spp is a frequent cause of diarrhea in children. Antimicrobials decrease the duration of diarrhea and pathogen excretion. However, the increasing resistance limits their therapeutic value. Aim: To study Shigella serotype distribution in the Metropolitan Region in Chile, and its relationship with severity of disease, antimicrobial resistance pattern and clonality. Material and methods: During summer 2004-2005, stool samples from children with diarrhea were collected in Cary Blair transpon medium and cultured. Shigella isolates were serotyped using monoclonal and polyclonal commercial antibodies. In vitro activity of ampicillin, amoxicillin/clavulanic acid, chloramphenicol, cotrimoxazol, nalidixic acid, ciprofloxacin, ceftriaxone and azythromycin was determined by minimal inhibitory concentration (MIC). Clonality was studied by pulsed-field gel electrophoresis (PFGE) using Xbal as restriction enzyme. Results: One hundred thirty nine Shigella strains were isolated (77 S sonnei and 62 S flexneri). S sonnei and S flexneri 2a serotypes were responsible for 95 percent of episodes. Children aged 2-4 years, showed a greater incidence of Shigella infections and 77 percent of episodes were treated on an ambulatory basis. High resistance levels were observed for ampicillin, cotrimoxazole, amoxicillin-clavulanic acid and chloramphenicol (67 percent, 60 percent, 56 percent and 45 percent, respectively). We found 11 resistance patterns and 61,2 percent of strains were multiresistant. There were multiple clones without a strict relationship with resistance patterns. Conclusions: Shigella infections in Metropolitan Region in Chile are associated to a restricted number of serotypes, representing a clonal expansion associated to different antimicrobial resistant patterns.

Choline supplementation facilitates short-term memory consolidation into intermediate long-term memory of young Sprague-Dawley rats / La suplementación con colina facilita la consolidación de la memoria a corto plazo y su transformación en memoria intermedia a largo plazo, en las Ratas Sprague-Dawley jóvenes

Choline is important for the synthesis of acetylcholine, an integral neurotransmitter involved in memory formation. In order to investigate the effect of choline supplementation on memory consolidation, the study utilized a T-maze to facilitate passive avoidance learning and memory in young female Sprague-Dawley rats. Rats were placed in two groups; choline-supplemented that received choline chloride daily for two weeks, and control that received vehicle daily for two weeks. Rats were evaluated to determine their ability to avoid an aversive electric foot-shock (0.1 mA at 60V) when they characteristically entered the preferred dark area (DA) of the T-maze. Both groups of rats showed preference, without significant difference, for entry into DA of the T-maze. However, fifteen minutes after passive avoidance both choline supplemented and control rats avoided entry into DA. This display of DA avoidance 15 minutes after training, suggests that both groups of rats had acquired short-term memory of the aversive stimulus. However, when the test was repeated 24 hours after training, the control group did not avoid entry into DA, whereas the choline-supplemented group either avoided entry or entered after a significantly longer latency period (p < 0.01). These results suggest that supplementation with choline facilitated the consolidation of short-term memory of the avoidance learning into intermediate long-term memory in young rats.

La colina es importante para la síntesis de la acetilcolina – un neurotransmisor integral que participa en la formación de la memoria. Para investigar el efecto de la suplementación con colina en la consolidación de la memoria, el estudio utilizó un laberinto T para facilitar la memoria y el aprendizaje de evitación pasiva en ratas hembras jóvenes Sprague-Dawley. Las ratas fueron colocadas en dos grupos: uno que recibió cloruro de colina diariamente por espacio de dos semanas, y uno de control que recibió vehículo diariamente por dos semanas. Las ratas fueron evaluadas a fin de determinar su habilidad para evitar un choque eléctrico aversivo (0.1mA a 60V) cuando entraban característicamente a la preferida área oscura (AO) del laberinto en T. Ambos grupos de ratas mostraron preferencia – sin diferencia significativa – por entrar en el área oscura del laberinto en T. Sin embargo, quince minutos después de la evitación pasiva, tanto las ratas que recibieron la suplementación con colina como las ratas de control, evitaban entrar al área oscura. El hecho de que se observe la evitación del área oscura15 minutos después del entrenamiento, sugiere que ambos grupos de ratas habían adquirido una memoria a corto plazo del estímulo aversivo. Sin embargo, cuando la prueba se repitió 24 horas después del entrenamiento, el grupo de control no evitó el entrar al AO, mientras que el grupo que recibió el complemento de colina, o evitó entrar o entró luego de un período de latencia significativamente más largo (P < 0.01). Por lo tanto, estos resultados sugieren por consiguiente que la suplementación con colina facilitó la consolidación de la memoria a corto plazo del aprendizaje de la evitación, y su transformación en memoria a largo plazo en las ratas jóvenes.

Multicollinearity may lead to artificial interaction: an example from a cross sectional study of biomarkers.

Collinearity is the situation which arises in multiple regression when some or all of the explanatory variables are so highly correlated with one another that it becomes very difficult, if not impossible, to disentangle their influences and obtain a reasonably precise estimate of their effects. Suppressor variable is one of the extreme situations of collinearity that one variable can substantially increase the multiple correlation when combined with a variable that is only modestly correlated with the response variable. In this study, we describe the process by which we disentangled and discovered multicollinearity and its consequences, namely artificial interaction, using the data from cross-sectional quantification of several biomarkers. We showed how the collinearity between one biomarker (blood lead level) and another (urinary trans, trans-muconic acid) and their interaction (blood lead level* urinary trans, trans-muconic acid) can lead to the observed artificial interaction on the third biomarker (urinary 5-aminolevulinic acid).

Tat mediates transcriptional activation of HIV-1 gene in vitro.

Gene expression of human immunodeficiency virus (HIV-1) is greatly enhanced by a viral transactivator, the Tat protein, which interacts with R region sequences of the HIV-1 long terminal repeat (LTR). There is no direct evidence to indicate transcriptional activation of HIV-1 by Tat. Using an in vitro transcription system, we demonstrate that an established mouse cell line, which constitutively expresses Tat protein, selectively stimulates the steady state levels of the transcripts directed from the long terminal repeat (LTR) sequences of HIV-1. The gel binding retardation assays further demonstrate a stable activated complex, formed due to direct binding of Tat to DNA elements of the HIV-1 LTR. These data implicate transcription as the site of Tat action in trans-activation and could play an essential role in human immunodeficiency virus replication, similar to the nuclear trans-activators of other viruses.

Toxicity of the hyperglycaemic-inducing extract of the Annatto (Bixa orellana) in the dog

The Annatto seed coat extract, which is commonly used in folklore in treating diabetes mellitus, has been investigated for its effects on blood sugar levels in the dog. An alkali-soluble hyperglycaemia-inducing fraction was detected, and detailed studies revealed toxic effects in the pancreas and liver accompanied by hyperglycaemia and apparent tendency to increased insulin levels. The toxicity was diminished by feeding riboflavin. The relevance of this finding points to a possible aetiological role in the development of amlnutrition-related diabetes mellitus and also to the potential toxicity inherent in the widespread use of folklore medicines