RESUMENLas encefalopatías espongiformes transmisibles (EETs) son enfermedades neurodegenerativas fatales que afectan a humanos y ciertas especies animales. La hipótesis más aceptada indica que el agente infeccioso, denotado como prion y compuesto principalmente por la Proteína Priónica Scrapie (PrP Sc ), corresponde a una conformación anormal de una proteína codificada por el huésped denominada Proteína Priónica Celular (PrP C ), cuya función es aún desconocida; sin embargo, la expresión ubicua de PrP C así como su elevado grado de conservación entre especies, sugieren un papel importante para esta proteína. En este trabajo se detectó a la PrP C en diferentes tipos celulares incluyendo un cultivo primario de células de peces (Tilapia, Oreochromis spp.). Además, basándonos en la secuencia de la PrP C humana, se diseñó un RNA de interferencia (siRNA) con el fin de silenciar el gen PRNP en células neuronales SK-SY5Y. El siRNA diseñado inhibió la expresión de PrP C a lo largo de las 96 h post-transfección y las células silenciadas fueron menos susceptibles a la infección por HSV-1 y HSV-2, en comparación con células no transfectadas con el siRNA. PALABRAS CLAVE: Proteína Priónica, PrP C , siRNA, HSV-1, HSV-2. ABSTRACTThe transmissible spongiform encephalopathies (TSEs) are neurodegenerative and fatal diseases, affecting humans and some other animal species. The most accepted hypothesis suggests that the infectious agent, named "prion", is composed mainly by the prion protein scrapie (PrP Sc ) and it corresponds to an abnormal conformation of a host encoded protein, the cellular prion protein (PrP C ), which function is still unknown. However, the ubiquitous expression of PrP C and its highly conserved presence among different species suggests it has a very important role in cell functions. In this work, the PrP C in different cell types, including a primary fish cell culture (Oreochromis spp.), was detected. In addition, based on the human PrP C sequence, we designed a short interfering RNA (siRNA) to silence the PRNP gen in neuronal SK-SY5Y cells. The designed siRNA inhibited the PrP C expression along 96 hours posttransfection and the silenced cells were less susceptible to HSV-1 and HSV-2 infections, in comparison to non siRNA-transfected cells.

Background: Hepatitis B virus (HBV) mutations conveying resistance to antivirals are a major health concern worldwide in the treatment of chronic hepatitis B infection. The availability of a sensitive assay that can detect emerging HBV antiviral resistance mutations is important for individualized monitoring of response to standard of care treatment. The risk of developing lamivudine (LAM) resistance is 14% to 70% after 1 to 5 years of treatment, which is sufficiently high to justify HBV antiviral resistance mutation testing. On the other hand, resistance to adefovir (ADV) is slow to emerge, ranging from 3% to 29% following 1 to 5 years of treatment. Mutation analysis helps in decision-making for clinical management of chronic HBV infection and molecular epidemiological studies as well. This study seeks to determine the presence of LAM and ADV resistance mutations among Filipino patients clinically diagnosed with chronic hepatitis B from July 2008 to December 2011.Methods: A total of fourteen samples were examined for the presence of antiviral resistance mutations using line probe assay, INNO-LiPA HBV DR v2. There were 9 (64%) males and 5 (36%) females with ages ranging from 17 to 69 years old.Results: Among the fourteen samples, 5 (36%) had wild-type, 4 (28%) had HBV mutant strain DNA not detected, and 5 (36%) had HBV DNA mutations. Out of the 5 HBV DNA mutant strains, one or 20% had one-drug resistance mutation detected (rtA181T for ADV). Three or 60% had 3-drug resistance mutations pattern detected. The first patient had rtG173L for LAM compensatory mutation, rtL180M for LAM, and rtM204V for LAM. The second patient had rtL80I for LAM compensatory mutation, rtL180M for LAM, and rtM204I for LAM, telbivudine (TBV). The third patient had L180L/A181T upcoming resistance for ADV, M204I upcoming resistance for LAM, emtricitabine, TBV, and N236T upcoming resistance for ADV. The remaining one or 20% had 4 drug-resistance mutations detected (rtA181T for ADV, rtL180M for LAM, rtM204V for LAM, and rtM204I for LAM, TBV).Conclusion: The most frequently encountered LAM-resistant mutant was rtM204V/I. Overall, the line probe assay provides a useful tool for the detection of lamivudine and adefovir resistance mutations among HBV-infected Filipino patients. http://dx.

When you hear the word virus, you might think of diseases like rabies, influenza, or COVID-19. Viruses are organisms that must infect living cells to reproduce. Studies done on cells grown in the lab, called cell cultures, have contributed significantly to our understanding of viral diseases and to the development of treatments and vaccines. In the laboratory, cells can be grown in layers or in three-dimensional systems. By infecting cell cultures with viruses, scientists can study various aspects of the infection, such as how the virus gets into the cells or how the cells respond to infection. Knowledge gained from infecting cell cultures with viruses has helped scientists to vastly improve human health!