Immunopathology of lymphocytic choriomeningitis viurs infection of newborn mice. Antithymocyte serum effects on glomerulonephritis and wasting disease.

Antithymocyte serum, when administered neonatally to mice, delayed the maturation of the lymphoid system, permitting development of cellular tolerance to LCM virus at an older age than is ordinarily possible. Humoral antibody formation was not prevented and the animals exhibited the paradox of high titers of both circulating virus and antibody. This, in turn, was followed by a chronic immunopathologic glomerulonephritis in most animals. Some animals developed wasting disease between 1 and 2 months of age, characterized by reticular cell hyperplasia and widespread infiltration into tissues and organs.

Cellular immunity in vaccinia infection of mice. Anti-thymocyte serum effects on primary and secondary responsiveness.

Rabbit anti-mouse thymocyte serum suppressed host cell-mediated responsiveness to intravenously administered vaccinia virus, thereby augmenting the morbidity and mortality of this infection. It did not affect either humoral antibody or interferon production in response to vaccinia virus. No effects were noted on primary or secondary immunity to intracerebral virus inoculation.

Agent of disease contracted from green monkeys.

An infectious agent obtained from patients who became ill after exposure to tissues of African green monkeys is viral in character. By electron microscopy, the agent appeared cylindrical, 90 to 100 nanometers in diameter, and 130 to 2600 nanometers in length. Cross-striations at 5-nanometer intervals and a core diameter of 45 nanometers were observed. The agent was completely resistant to the effects of the metabolic inhibitor 5-bromodeoxyuridine, which may mean that RNA is the genetic material. It was sensitive to ether and relatively sensitive to destruction by heat.

Murine oncornavirus activation in the pancreas during infection with Venezuelan equine encephalitis virus.

Electron microscopic studies of the pancreases of 3-week-old ICR Swiss mice infected with Venezuelan equine encephalitis virus and killed 6 days post inoculation (at which time they were moribund) indicated significantly more type-C particles than were found in uninfected controls. This phenomenon was apparently possible because of the microanatomy of the pancreas, in which interstital spaces allowed accumulation of virus particles.

Historical Perspective: What Constitutes Discovery (of a New Virus)?

A historic review of the discovery of new viruses leads to reminders of traditions that have evolved over 118 years. One such tradition gives credit for the discovery of a virus to the investigator(s) who not only carried out the seminal experiments but also correctly interpreted the findings (within the technological context of the day). Early on, ultrafiltration played a unique role in "proving" that an infectious agent was a virus, as did a failure to find any microscopically visible agent, failure to show replication of the agent in the absence of viable cells, thermolability of the agent, and demonstration of a specific immune response to the agent so as to rule out duplicates and close variants. More difficult was "proving" that the new virus was the etiologic agent of the disease ("proof of causation")-for good reasons this matter has been revisited several times over the years as technologies and perspectives have changed. One tradition is that the discoverers get to name their discovery, their new virus (unless some grievous convention has been broken)-the stability of these virus names has been a way to honor the discoverer(s) over the long term. Several vignettes have been chosen to illustrate several difficulties in holding to the traditions (vignettes chosen include vaccinia and variola viruses, yellow fever virus, and influenza viruses. Crimean-Congo hemorrhagic fever virus, Murray Valley encephalitis virus, human immunodeficiency virus 1, Sin Nombre virus, and Ebola virus). Each suggests lessons for the future. One way to assure that discoveries are forever linked with discoverers would be a permanent archive in one of the universal virus databases that have been constructed for other purposes. However, no current database seems ideal-perhaps members of the global community of virologists will have an ideal solution.

Molecular profiling reveals primary mesothelioma cell lines recapitulate human disease.

Malignant mesothelioma (MM) is an aggressive, fatal tumor strongly associated with asbestos exposure. There is an urgent need to improve MM patient outcomes and this requires functionally validated pre-clinical models. Mesothelioma-derived cell lines provide an essential and relatively robust tool and remain among the most widely used systems for candidate drug evaluation. Although a number of cell lines are commercially available, a detailed comparison of these commercial lines with freshly derived primary tumor cells to validate their suitability as pre-clinical models is lacking. To address this, patient-derived primary mesothelioma cell lines were established and characterized using complementary multidisciplinary approaches and bioinformatic analysis. Clinical markers of mesothelioma, transcriptional and metabolic profiles, as well as the status of p53 and the tumor suppressor genes CDKN2A and NF2, were examined in primary cell lines and in two widely used commercial lines. Expression of MM-associated markers, as well as the status of CDKN2A, NF2, the 'gatekeeper' in MM development, and their products demonstrated that primary cell lines are more representative of the tumor close to its native state and show a degree of molecular diversity, thus capturing the disease heterogeneity in a patient cohort. Molecular profiling revealed a significantly different transcriptome and marked metabolic shift towards a greater glycolytic phenotype in commercial compared with primary cell lines. Our results highlight that multiple, appropriately characterised, patient-derived tumor cell lines are required to enable concurrent evaluation of molecular profiles versus drug response. Furthermore, application of this approach to other difficult-to-treat tumors would generate improved cellular models for pre-clinical evaluation of novel targeted therapies.

Anticonvulsant prolongation of survival in adult murine lymphocytic choriomeningitis. II. Ultrastructural observations of pathogenetic events.

Because previous ultrastructural studies of murine lymphocytic choriomeningitis (LCM) had revealed only mononuclear cell infiltration with no cytopathology of target cells in the choroid plexus, ependyma, and leptomeninges, diazepam treatment was used to prolong survival for characterization of late pathogenetic events. Mice which were treated with diazepam and sacrificed 8, 9, and 10 days after intracerebral inoculation with LCM virus showed an increasing amount of inflammatory infiltration into choroid plexuses, leptomeninges, Virchow-Robin spaces, and ependyma. Mononuclear cells, lymphocytes, and polymorphonuclear (PMN) leukocytes increased in number as compared with terminally infected mice sacrificed 7 days after inoculation. Ultrastructurally, choroidal epithelial cells showed cytopathological changes varying from dilated endoplasmic reticulum through necrosis. Greater numbers of PMN leukocytes, macrophages, and activated macrophages and fewer undifferentiated mononuclear cells were seen in choroid plexuses of the drug-treated survivors. Virions and larger, more numerous arenavirus inclusions were present in choroid plexus and ependyma. Ultrastructurally the leptomeningitis was characterized by large numbers of activated macrophages. Choroidal epithelial necrosis appears to be the in vivo correlate of T-cell-mediated cytotoxicity in vitro.

Anticonvulsant prolongation of survival in adult murine lymphocytic choriomeningitis. I. Drug treatment and virologic studies.

Lymphocytic choriomeningitis virus-induced central nervous system disease is characterized by death during a seizure approximately seven days after intracerebral inoculation. This process is mediated by thymus dependent lymphocytes, sensitized against viral antigens. Various forms of immunosuppressive treatment prevent the seizure death and produce persistently infected survivors. In this study, anticonvulsant treatment (particularly diazepam treatment) of LCM virus infected mice prolonged survival without affecting viral replication, or suppressing immune responsiveness. This prolongation of life did not lead to a reversal of pathologic processes and there were no survivors. However, anticonvulsant treatment permitted study of more advanced stages of the choriomeningitis than has previously been possible.

Sexual dimorphism and developmental expression of signal-transduction machinery in the vomeronasal organ.

We have explored the use of a new model to study the transduction of chemosignals in the vomeronasal organ (VNO), for which the functional pathway for chemical communication is incompletely understood. Because putative vomeronasal receptors in mammalian and other vertebrate models belong to the superfamily of G-protein-coupled receptors, the objective of the present study was to define which G-protein subunits were present in the VNO of Sternotherus odoratus (stinkpot or musk turtle) in order to provide directionality for future functional studies of the downstream signaling cascades. The turtle vomeronasal epithelium (VNE) was found to contain the G-proteins G(beta) and G(alphail-3) at the microvillar layer, the presumed site of signal tranduction in these neurons, as evidenced by immunocytochemical techniques. G(alphao) labeled the axon bundles in the VNE and the somata of the vomeronasal sensory neurons but not the microvillar layer. Densitometric analysis of Western blots indicated that the VNO from females contained greater concentrations of G(alphai1-3) compared with males. Sexually immature (juvenile) turtles showed intense immunolabeling for all three subunits (G(beta), G(alphai1-3), and G(alphao)) in the axon bundles and an absence of labeling in the microvillar layer. Another putative signaling component found in the microvilli of mammalian VNO, transient receptor potential channel, was also immunoreactive in S. odoratus in a gender-specific manner, as quantified by Western blot analysis. These data demonstrate the utility of Sternotherus for discerning the functional signal transduction machinery in the VNO and may suggest that gender and developmental differences in effector proteins or cellular signaling components may be used to activate sex-specific behaviors.

Congo-Crimean haemorrhagic fever in Dubai: histopathological studies.

Necropsies were carried out on two patients who died of Congo-Crimean haemorrhagic fever (C-CHF) in Dubai. The diagnosis was confirmed by isolation of C-CHF virus from the liver. Histopathological changes included extensive cellular necrosis and haemorrhage in the liver, necrosis and lymphoid depletion in the spleen, congestion and oedema formation in the lungs, and haemorrhage in a number of other organs.

Cellular resistance to arbovirus infection.

When an arbovirus enters an arthropod in an infected blood meal, several mechanisms may interact to affect its life cycle and ultimate transmissibility. Intrinsic absolute failure in the establishment of infection must be contrasted with infection that is successfully established but is variably modulated in its viral yield throughout the vector's life-span. Degrees of vertebrate host resistance make this modulation a central factor in determining whether an arthropod is an important vector in nature; moreover, human intervention that affects modulating mechanisms may become a basis for disease control. In the absence of evidence of real immune resistance to arbovirus infections in arthropods, other more primitive modulating mechanisms must be considered: interferonlike substances may be formed in arthropod cells; arthropod cells may "cure" themselves by a unique endophagocytic digestion of their virus burden; homologous interference with viral replicative processes may be mediated via wild or mutant viral RNA species acting to shut down further RNA synthesis; and homologous interference may be mediated by RNA of defective-interfering virus formed earlier in infection.

The evolution of viruses, the emergence of viral diseases: a synthesis that Martinus Beijerinck might enjoy.

The relentless production of viral variants and their selection for improved "fit" are seen from the perspective of the infectious disease sciences as ever-changing viral phenotypes and emerging disease risks. In the Darwinian cause:effect equation, we can characterize very well the effects of mutation and selection--these are catalogued as new viral phenotypes or pathotypes. However, the selective forces themselves driving such changes remain rather mysterious. Many selective forces must be at work, acting on the virus, the host, the host population and the environment. In some instances the virus seems to test new unoccupied niches in the absence of any apparent environmental change, but usually it is clear that changes are driven by human activity. Most important must be the ever increasing density of human, domestic animal and crop plant populations and the consequent increased opportunities for transmission of viral variants. Also important must be the great changes affecting all ecosystems--these especially favor the emergence of new zoonotic viruses and viral "species jumpers." The great increase in human travel and transport carries exotic viruses, vectors and hosts around the world, again favoring viral occupation of new niches. The rise of bioterrorism adds yet another threat. Increasing numbers of emerging viral disease episodes seem to be linked to a decline in global resources for proven public health programs, agricultural extension programs, and the like, programs that have stood in the way of the spread and evolution of viral pathogens. If the relationship between viral evolution and the emergence of new viral diseases is rooted firstly in the host and the host population, then more research and resources must be directed to intervention at these levels rather than at the level of the viruses themselves.

The epidemiology of infectious diseases of livestock.

From the time of the first modern studies of infectious diseases, by Koch, Pasteur, Theiler and their colleagues, it has been clear that laboratory investigation must be complemented by epidemiologic investigation. The measurement of all aspects of the natural history of a disease in naturally affected populations is necessary if we are to rationally design control regimens. Building upon a historic perspective, this paper presents a view of the present status of epidemiology as it pertains to animal disease control, and presents a view of the merits of expanding the use of this science in future animal disease control programs, internationally, in developed and developing countries. The basis for this view lies in adaptation of principles employed in human infectious disease epidemiology, and principles which guide the organization of international disease control agencies.

One step along the way: the introduction of supernumerary status for RGN students in Foresterhill College, Aberdeen.

This article describes the introduction of supernumerary status for RGN students. A revised modular scheme was implemented and the main aims were to introduce supernumerary status and to provide the students with an identified 'mentor'. The changes were evaluated from teacher, student and ward staff perspectives. Supernumerary status was introduced successfully but mentorship less so. Finally, the significant change is reflected upon in light of current and future changes in nurse education.

Applying lexical and semantic analysis to the exploration of free-text data.

A substantial study of primary nursing involving the authors ( 1 , 2 ) generated, in addition to the pre-coded data, a large number of free-text responses. We decided to investigate whether these less structured data could help to categorise and understand the leadership styles of ward sisters in the sample.