The physiology of oxygen metabolism in Group B N. meningitidis was investigated. The respiratory components of the electron transport chain included dehydrogenases, ubiquinone, multiple b- and c-type cytochromes, and cytochromes o and a as terminal oxidases. Independent variations in the respiratory components were determined for cells grown under different conditions of iron concentrations and aeration (including anaerobiosis). Studies on oxidase activities in envelope preparations suggested branching of the respiratory chain at the levels of dehydrogenases, cytochrome b and terminal oxidases. Work on L-cysteine oxidase activity associated with the envelope preparations indicated the presence of an additional "alternate" oxidase insensitive to terminal oxidase inhibitors. A soluble CO- and NO-binding c-type cytochrome was shown to be present in the supernatant fluids and might be involved in an ascorbate-TMPD oxidase activity. A model of a branched electron transport system is proposed. The levels of catalase, peroxidase and superoxide dismutase in the organism were shown to vary with the growth conditions.

This thesis describes the construction and evaluation of six knockout mutants in Neisseria meningitidis serogroup B strain MC58. The genes that were inactivated were NMB0711, NMB1048, NMB1525, NMB1898, NMB1948 and NMB1966. Attempts to inactivate a seventh gene, NMB0768, were not successful. These genes were chosen as they had been observed previously to be up-regulated following incubation in whole blood using Differential Fluorescence Induction. Mutant strains were constructed by allelic exchange with a plasmid construction in which a kanamycin resistance cassette had been incorporated within the coding sequence of each cloned target gene. Confirmation of successful allelic exchange was achieved by Southern blotting. The phenotype of all mutant strains were evaluated by assessment of in vitro growth and in the infant mouse model of infection. Of the six mutants, all except that involving NMB1966, showed no differences compared with wild-type. The mutant knockout of NMB1966 showed (1) impaired growth beyond the mid-logarithmic phase in shaking broth culture but normal growth on solid medium, (2) reduced virulence in a mouse model of infection, (3) impairment in its capacity to invade (although not adhere to) cultured human bronchial epithelial cells, and (4) more rapid killing in ex vivo human blood. NMB1966 is predicted to encode the ATP-binding subunit of an ABC transporter and, after experiments for this thesis had been completed, it was demonstrated, by others, that this ABC transporter is responsible for uptake of L-Glutamate at low sodium concentrations. It is likely that defective uptake of L-Glutamate explains the observed defect in shaking broth culture and intracellular survival, both of which are associated with low ambient concentrations of sodium. However, it is not certain if this mechanism explains the observed defect in survival in human blood and in the infant mouse model which test predominantly extracellular survival and represent environments with high sodium concentrations.

Thesis (Ph.D.)--George Mason University, 2009. / Vita: p. 102. Thesis director: Serguei G. Popov. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biosciences. Title from PDF t.p. (viewed June 10, 2009). Includes bibliographical references (p. 84-101). Also issued in print.

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O presente trabalho estuda algumas características epidemiológicas de 241 casos de Meningite tuberculosa de pessoas residentes na Grande São Paulo, nos anos de 1982 e 1983. O levantamento de casos foi realizado no Centro de Investigações de Saúde e outras fontes oficiais de informação e complementado pela visitação domiciliária que representou um recurso inestimável para o esclarecimento dos dados. Os casos foram analisados por região de residência, aspectos individuais, núcleos familiares, história da doença, hospitalização, seqüência de tratamento e conhecimento sobre a doença. Os resultados identificam condições insatisfatórias de vida na maioria da população, demora no diagnóstico por falhas assistenciais, alta letalidade hospitalar e desconhecimento do modo de transmissão e prevenção da tuberculose pela maioria das pessoas entrevistadas. O grupo de menores de 5 anos de idade foi o mais comprometido pela ocorrência de seqüelas e, a maior letalidade oi na faixa de 7-12 meses. Ao final do estudo, houve 45,7 por cento de cura, 27,8 por cento de óbito, 13,3 por cento de abandono. Em 13,2 por cento dos casos, alguns permaneciam em observação e outros desconhecidos pelo sistema de controle de notificações. / The present paper studies some epidemiological characteristics of 241 cases of tuberculous miningitis in persons living in the Great São Paulo, State of São Paulo, Brazil, in 1982 and 1983. The survey of cases was worked out at the Center of Health Investigation; other official sources have been consulted, too, being work complemented by domiciliary visitings which represented an invaluable resource for data enlightenment. The cases were analysed taking into account region of dwelling, individual aspects, familiar nucleus, disease history, hospitalization, treatment follow-up and knowledge about the disease. Results identify unsatisfactory life conditions for the majority of the population under study; delay in diagnosing the disease due to failures in assistance; high rate of hospital lethality and lack of knowledge on how tuberculosis is transmitted and prevented by the majority of the persons interviewed with. The age group of children below five years was the one most implicated in as to the occurence of the highest rate of lethality was presented by children aged 7-12 months. At the end of the study, there were 45.7 per cent of healings; 27.8 per cent of deaths; 13.3 per cent of treatment abandonment. In 13.2 per cent of the cases, some persons continued under observation and others remained unknown by the Health System of notifications.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Objectives: Diagnosis of tuberculous meningitis (TM) is a challenge in countries with a high burden of the disease and constrained resources and clinical prediction rules (CPRs) could be of assistance. We aimed at developing a CPR for diagnosis of TM in a Latin American setting with high tuberculosis incidence and a concentrated HIV epidemic. Methods: We enrolled adult patients with clinical suspicion of TM attending two hospitals in Lima, Peru. We obtained information on potential anamnestic, clinical and laboratory predictive findings that are easy to collect and promptly available. We independently diagnosed TM according to a composite reference standard that included a series of microbiological tests. We performed bivariate analysis and constructed a logistic regression model to select the predictive findings associated with TM. With the selected predictors included in the model, we developed a score-based CPR. We assessed its internal validity and diagnostic performance. Results: Of 155 analysed patients, 59 (38%) had TM. The CPR we derived includes three predictors: cough for 14 days or more, 10–500 cells in CSF and adenosine deaminase ≥ 6 U/l in CSF. It classifies patients into high-, moderate- or low-score groups and has an overall area under the ROC curve of 0.87. 59% of patients were assigned to either the high- or the low-score group, permitting prompt decision-making. In patients in the high-score group, it attains a positive likelihood ratio for TM of 10.6 and in patients with low scores, a negative likelihood ratio of 0.10. Bootstrap analysis indicated high internal validity. Conclusion: This CPR could support decision-making in patients with clinical suspicion of TM. External validation and further assessment of its clinical impact are necessary before application in other settings. / Revisión por pares

No description available.

No description available.

The primary approach to the control of meningococcal disease remains effective vaccination programmes in susceptible populations. Vaccines against serogroups A, C, W and Y offer broad protection against meningococci and both polysaccharide and conjugate quadrivalent vaccines are licensed for use in the UK. Previous studies have assessed the antibody response to meningococcal polysaccharide and conjugate vaccines, but there is limited information on the nature of the B cell response to these antigens. As part of a clinical trial using both polysaccharide (MenACWY-PS) and conjugate (MenACWY-CRM) vaccines in adult volunteers, this DPhil reports the analysis of subsets of antigen specific B-cells produced in response to either vaccine. Prior MenACWY-PS impaired the response to a subsequent dose of MenACWY-CRM. This may be due to MenACWY-PS driving terminal differentiation of antigen specific cells into plasma cells, without replenishment of the memory B cell pool. In addition, despite prior data indicating that it may act as a thymus dependent antigen, the serogroup A polysaccharide component of MenACWY-PS appears to behave in the same way as serogroup C, W & Y polysaccharide components. Antibody molecules recognise and bind to a multitude of conformational epitopes. This variability is enabled by the complexities of immunoglobulin variable domain gene recombination which can generate a vast potential repertoire of unique antibody molecules. However, the diversity of the antibody repertoire is more restricted against specific antigens and within defined B cell subsets. In this DPhil, ‘next generation’ sequencing technologies were used to investigate the diversity of the B cell variable domain before and after vaccination of adult volunteers. Individuals at baseline were found to have distinct antibody repertoires. Vaccination with a Haemophilus influenzae type b (Hib) conjugate vaccine resulted in an oligoclonal antibody response, with enrichment for Hib specific canonical antibody sequences.

Escherichia coli ist eine der Hauptursachen von Meningitis und Meningoencephalitis in älteren und immunsupprimierten Patienten sowie von der durch Gram-negative Bakterien verursachten Meningitis bei Säuglingen. In der vorliegenden Arbeit untersuchten wir den Beitrag der neutrophilen Granulozyten und der TLR-Signalkaskade zur Resistenz adulter Mäuse gegen eine intrazerebrale Escherichia-coli-K1-Infektion, anhand von Mäusen, deren neutrophile Granulozyten durch den Anti-Ly-6G-Antikörper depletiert wurden sowie mit Hilfe von MyD88-defizienten und TRIF-defizienten Mäusen. Ein Mangel an MyD88-Adapter-Proteinen reduzierte dramatisch das Überleben der Tiere, während das Fehlen von TRIF-Adapter-Proteinen keine Einschränkung im Überleben nach sich zog im Vergleich zu den Wildtypmäusen. Die Depletion der neutrophilen CD11b+Ly-6G+Ly-6Cint-Granulozyten durch intraperitoneale Injektion des Anti-Ly-6G-Antikörpers führte zu höheren bakteriellen Titern im Kleinhirn und in der Milz und schließlich zu einer erhöhten Letalität im Vergleich zu den mit dem Isotyp behandelten Mäusen. Unsere Ergebnisse zeigen, dass der den Toll-like-Rezeptoren nachgeschaltete MyD88-Signalweg und die neutrophilen Granulozyten wichtige Elemente in der Immunabwehr während der Frühphase einer Escherichia-coli-Meningitis sind. Wie bereits in verschiedenen Experimenten gezeigt wurde, können CpG-ODNs Tiere vor verschiedenen Infektionen schützen (Elkins et al. 1999; Barrier et al.2006). Vor diesem Hintergrund prüften wir, ob eine prophylaktische Behandlung mit CpG-ODN ebenfalls vor einer experimentell erzeugten Infektion des Zentralen Nervensystems schützt. Dazu wurden Mäuse, denen mit Hilfe des Anti-Ly-6G-Antikörpers eine Neutropenie induziert wurde, sowie immunkompetente Mäuse und TLR9-defiziente Mäuse jeweils intrakraniell mit Escherichia coli K1 infiziert. Drei Tage vor der Infektion bekamen die Mäuse der CpG-Gruppen eine einmalige intraperitoneale Injektion von 100 μg CpG-ODN. Hierbei zeigte sich, dass die Behandlung mit CpG-ODN die Letalität nach einer intrazerebralen Infektion von 66 % auf 23 % bei den neutropenischen Mäusen senkte (P = 0,0002, Log-Rank-Test). Zusätzlich wiesen die mit CpG-ODN behandelten Mäuse 42 Stunden nach Infektion geringere bakterielle Titer im Kleinhirn und in der Milz auf, als es in den mit Puffer behandelten Tieren der Fall war (P = 0,01 und P = 0,04, Mann-Whitney-U-Test). In den immunkompetenten Mäusen war die Letalität der mit CpG-ODN behandelten Mäuse leicht niedriger im Vergleich zur Puffergruppe, es konnte jedoch kein statistisch signifikanter Unterschied gefunden werden. TLR9-defiziente Mäuse erhielten keinen schützenden Effekt durch die prophylaktische Behandlung mit CpG-ODN. Dies zeigt, dass die prophylaktische Behandlung mit CpG-ODN nicht nur während einer systemischen Infektion einen Vorteil bringt, sondern ebenfalls die Resistenz von neutropenischen Mäusen gegen eine ZNS-Infektion mit Escherichia coli erhöht. Somit könnte CpG-ODN in Zukunft ein Mittel bieten, um neutropenische Patienten prophylaktisch vor einer Escherichia-coli-K1-Meningitis zu schützen und ihnen somit schwere Verlaufsformen und Komplikationen der Krankheit zu ersparen.