Growth hormone secretagogue peptide-6 enhances oreochromicins transcription and antimicrobial activity in tilapia (Oreochromis sp.).

Growth Hormone-Releasing Peptide 6 (GHRP-6) (His-(D-Trp)-Ala-Trp-(D-Phe)-Lys-NH2) is an agonist of the growth hormone secretagogue receptor. GHRP-6 mimics the effect of ghrelin. The present study focuses on the immunomodulatory effects of GHRP-6 in tilapia with and without the presence of Pseudomonas aeruginosa infection. GHRP-6 up-regulated the transcription levels of three piscidin-like antimicrobial peptides (Oreochromicins I, II, and III) and granzyme in a tissue-dependent manner. Antimicrobial activity stimulation in serum (lysozyme and anti-protease activity) was also confirmed. Besides, GHRP-6 enhanced the in vitro antimicrobial activity against P. aeruginosa in tilapia gills mucus and serum samples and decreased the bacterial load in vivo after infection with this Gram-negative bacterium. Our results evidenced, for the first time, a direct link between a growth hormone secretagogue ghrelin mimetic in fish and the enhancement of antimicrobial peptides transcription, which suggests that this secretagogue is capable to lead the activation of microbicidal activity in tilapia. Thus, these results open new possibilities for GHRP-6 application in aquaculture to stimulate the teleost immune system as an alternative treatment against opportunistic bacteria.

Silent celiac disease in a cohort of healthy adults.

BACKGROUND: Recent studies suggest that celiac disease (CD) is common in many developing countries. Because the disease may be under diagnosed in Cuba, we studied the presence of the disease in a group of apparently healthy adult. AIMS/HYPOTHESIS: It was to assess for the first time, the presence of silent CD in a cohort of healthy Cuban adults individuals and to evaluate the tools for diagnosis of CD in this group. METHODS: A total of 200 healthy Cuban adult from Havana City were evaluated. Tissue transglutaminase antibodies (tTGA) were determined by one-step immunochromatographic assay and by commercial ELISA kit. CD specific human leukocyte antigen (HLA) typing was performed by polymerase chain reaction amplification, using sequence-specific primers. In the subject positive for tTGA, the CD was confirmed by intestinal biopsy. RESULTS: From the 200 studied individuals, only one subject was identified as positive by both assays, being submitted to duodenal biopsy. Morphological changes consistent with CD were found and also supported by HLA-DQ2 (HLA-DQA1*0501-DQB1*02). In the follow-up after one year, histological recovery was assessed by a second intestinal biopsy and the serological marker became negative. CONCLUSIONS: This study confirms the existence of silent CD among healthy adult in Cuba and highlights the importance of mass screening for this disease among them. The one-step immunochromatographic assay is a good tool for this purpose.

Purificación del antígeno recombinante del core de la hepatitis B y su uso potencial en el diagnóstico de la infección con el virus de la hepatitis B / Purification of the recombinant hepatitis B core antigen and its potential use for the diagnosis of hepatitis B virus infection

El gen del HBcAg del VHB fue clonado en el vector de expresión pRIV-2 y usado para la síntesis en E. coli de la proteína de 22 kD. La proteína expresada fue capaz de ensamblarse en forma de partícula con un nivel de expresión del 7(por ciento) con respecto al total de proteínas de E. coli presentes en una SDS-PAGE del 15 (por ciento). El HBcAg fue purificado hasta un 90 (por ciento) utilizando una combinación de dos pasos de precipitación con sulfato de amonio y una cromatrografía de filtración en gel de sepharose CL-4B. El recobrado total del método propuesto fue del 47(por ciento). El uso en el diagnóstico de la infección por el VHB fue evaluado por ELISA mediante un panel de sueros positivos y negativos. Los valores obtenidos de 99,3(por ciento) de especificidad y 97,9(por ciento) de sensibilidad demostrarón el uso potencial del HBcAg purificado en el serodiagnóstico de la infección con el VHB(AU)