Biosafety and biosecurity in veterinary laboratories.

With recent outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV), anthrax, Nipah and the highly pathogenic avian influenza virus, much emphasis has been placed on the rapid identification of infectious agents globally. As a result, laboratories are building capacity, conducting more advanced and sophisticated research, increasing their staff, and establishing reference collections of dangerous pathogens in an attempt to reduce the impact of infectious disease outbreaks and to characterise disease-causing agents. With this expansion, the global laboratory community has started to focus on laboratory biosafety and biosecurity in order to prevent the accidental and/or intentional release of these agents. Laboratory biosafety and biosecurity systems are used around the world to help to mitigate the risks posed by dangerous pathogens in the laboratory. Veterinary laboratories carry unique responsibilities with regard to workers and communities to handle disease-causing microorganisms safely and securely. Many microorganisms studied in veterinary laboratories not only infect animals, but also have the potential to infect humans. This paper will discuss the fundamentals of laboratory biosafety and biosecurity.

Suite aux nombreux foyers récents dus à divers agents pathogènes (coronavirus responsable du syndrome respiratoire du Moyen-Orient [MERS-CoV], agent de la fièvre charbonneuse, virus Nipah, virus de l'influenza aviaire hautement pathogène), la nécessité d'identifier rapidement les agents pathogènes en n'importe quel endroit de la planète est désormais au centre des préoccupations. Par conséquent, les efforts des laboratoires sont axés sur le renforcement des capacités, la conduite de travaux de recherche de pointe de plus en plus spécialisés, l'accroissement des effectifs et l'élaboration de référentiels d'agents pathogènes dangereux dans le but de réduire l'impact des foyers de maladies infectieuses et de caractériser les agents responsables de ces maladies. Dans ce contexte d'activité accrue, le réseau international des laboratoires a commencé à accorder une grande importance aux questions de biosûreté et de biosécurité afin de se prémunir contre le risque de libération accidentelle et/ou délibérée de ces agents pathogènes. Les systèmes de biosécurité et de biosûreté sont appliqués dans le monde entier pour contribuer à l'atténuation des risques liés aux agents pathogènes dangereux détenus par les laboratoires. Les laboratoires vétérinaires ont à l'égard de leur personnel et de la société tout entière la responsabilité majeure de garantir la sécurité et la sûreté de la manipulation des microorganismes pathogènes. En plus d'infecter les animaux, nombre des microorganismes analysés dans les laboratoires vétérinaires ont également un potentiel zoonotique. Les auteurs examinent les aspects essentiels de la biosécurité et de la biosûreté au laboratoire.

Los recientes brotes de coronavirus del síndrome respiratorio de Oriente Medio (MERS-CoV), carbunco bacteridiano, virus de Nipah y virus de la influenza aviar altamente patógena han llevado a hacer especial hincapié en la rápida identificación de agentes infecciosos a escala mundial. Obrando en consecuencia, los laboratorios están dotándose de medios de acción, llevando a cabo investigaciones más avanzadas y sofisticadas, reforzando su plantilla y creando colecciones de referencia de patógenos peligrosos con la voluntad de reducir los efectos de los brotes infecciosos y caracterizar a los agentes patógenos. Al mismo tiempo, en todo el mundo los profesionales del ramo han empezado a prestar atención a la seguridad y la protección biológicas en el laboratorio, con el fin de prevenir toda liberación accidental y/o deliberada de los mencionados agentes. Los laboratorios del mundo entero emplean sistemas de seguridad y protección biológicas como elemento auxiliar para reducir los riesgos derivados de la presencia de patógenos peligrosos en sus instalaciones. Los laboratorios veterinarios tienen una especial responsabilidad para con los trabajadores y las poblaciones por lo que respecta a la manipulación de microorganismos patógenos en las debidas condiciones de seguridad y protección. Muchos de los microorganismos estudiados en los laboratorios veterinarios infectan no solo a los animales, sino también, en potencia, al ser humano. Los autores examinan los aspectos fundamentales de la seguridad y la protección biológicas en laboratorio.

Nonstructural protein 3-4A: the Swiss army knife of hepatitis C virus.

Hepatitis C virus (HCV) nonstructural protein 3-4A (NS3-4A) is a complex composed of NS3 and its cofactor NS4A. It harbours serine protease as well as NTPase/RNA helicase activities and is essential for viral polyprotein processing, RNA replication and virion formation. Specific inhibitors of the NS3-4A protease significantly improve sustained virological response rates in patients with chronic hepatitis C when combined with pegylated interferon-α and ribavirin. The NS3-4A protease can also target selected cellular proteins, thereby blocking innate immune pathways and modulating growth factor signalling. Hence, NS3-4A is not only an essential component of the viral replication complex and prime target for antiviral intervention but also a key player in the persistence and pathogenesis of HCV. This review provides a concise update on the biochemical and structural aspects of NS3-4A, its role in the pathogenesis of chronic hepatitis C and the clinical development of NS3-4A protease inhibitors.

Hepatitis C virus infection: in vivo and in vitro models.

Major advances in the understanding of the molecular biology of hepatitis C virus (HCV) have been made recently. While the chimpanzee is the only established animal model of HCV infection, several in vivo and in vitro models have been established that allow us to study various aspects of the viral life cycle. In particular, the replicon system and the production of recombinant infectious virions revolutionized the investigation of HCV-RNA replication and rendered all steps of the viral life cycle, including entry and release of viral particles, amenable to systematic analysis. In the following we will review the different in vivo and in vitro models of HCV infection.

Treatment and prophylaxis of severe infections in neutropenic patients by granulocyte transfusions.

Bacterial and fungal infections are the main cause of morbidity and mortality in neutropenic patients. To resolve infections, an adequate number of functional granulocytes is required. Successful treatment of severe infections with granulocyte transfusions is strongly dependent on an adequate number of transfused cells. In this study, 42 neutropenic patients received rhG-CSF-stimulated granulocyte transfusions (GTXs). Of these patients, 18 with severe infections during neutropenia and 8 in a high-risk situation, as defined by severe infections during previous periods of neutropenia or increasing infectious parameters during prolonged neutropenia, received a median of three GTXs (range 1-25), containing a median total of 2.62x10(10) leukocytes (range 0.3-8.61x10(10)). A further 16 patients in a pilot study received prophylactic GTX, consisting of a median of three GTXs (range 1-4) containing a median total of 3.20x10(10) leukocytes (range 0.73-8.51x10(10)). Out of 18 patients with severe infections, 12 improved clinically or showed a resolution of infection after GTX. All 8 patients in a high-risk situation showed a stable clinical course without serious infections. Prophylactic GTX did not result in significant differences with regard to infectious parameters. The median number of transfused platelet units during the course of cytopenia was significantly reduced (13.5 units vs 22.0 units, P<0.02) compared to the control group. For the treatment of infections during neutropenia, rhG-CSF-stimulated granulocyte transfusions are safe and a promising approach.

[Molecular virology of hepatitis C]. / Molekulare Virologie der Hepatitis C.

Hepatitis C virus (HCV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Here, we will briefly review current concepts of the molecular virology of hepatitis C. In vitro and in vivo models of HCV replication will be discussed in this context. Finally, novel antiviral strategies will be outlined that result from an improved understanding of the viral life cycle.

Measurement of telomere length in haematopoietic cells using in situ hybridization techniques.

The DNA of human chromosomes terminates in several kilobases of telomere repeats that are gradually lost with; age and with replication in vitro. Defective telomere maintenance has been shown to be causally linked to cell cycle exit and apoptosis. In order to overcome the limitations imposed by Southern blotting, we have established a quantitative fluorescence in situ hybridization (Q-FISH) technique. This technique allows estimation of telomere length in specific chromosome arms from metaphase cell preparations. Furthermore, we have extended quantitative in situ hybridization to flow cytometry (flow FISH) in order to obtain information on the mean telomere repeat content in suspended cells. Telomere length in granulocytes, monocytes, CD8 and CD4 T lymphocytes and natural killer cells was found to differ slightly in the peripheral blood of adults. However, strikingly longer telomeres were observed in B lymphocytes (approximately 1.3 kb longer), suggesting a functional role for telomere maintenance in this cell subset. In summary, Q-FISH and flow FISH represent new methods for measuring telomere length in single cells and allow studies of telomere dynamics in haematopoietic subpopulations at various stages of normal and abnormal antigen responses.