The role of CD4(+) cells in vivo on the induction of the immune response to Porphyromonas gingivalis in mice

Background: It has previously been suggested that CD4(+) T cells play a pivotal role in regulating the immune response to periodontal pathogens. The aim of the present study therefore was to determine delayed type hypersensitivity (DTH), spleen cell proliferation, serum and splenic anti-Porphyromonas gingivalis antibody levels, and lesion sizes following challenge with viable P. gingiualis in CD4-depleted BALB/c mice immunized with P. gingiualis outer membrane proteins (OMP). Methods: Four groups of BALB/c mice were used. Groups 1 and 2 were injected intraperitoneally (ip) with saline for 3 consecutive days and then weekly throughout the experiment. Groups 3 and 4 were injected ip with rat immunoglobulin and a monoclonal rat anti-mouse CD4 antibody, respectively. Two days later, group 1 mice were injected ip with saline only, while all the other groups were immunized ip with P. gingiualis OMP weekly for 3 weeks. One week later following the last immunization of OMP, 3 separate experiments were conducted to determine: 1) the DTH response to P. gingiualis OMP by measuring footpad swelling; 2) the levels of antibodies to P. gingiualis in serum samples and spleen cell cultures using an enzyme-linked immunosorbent assay, as well as spleen cell proliferation after stimulation with OMP; and 3) the lesion sizes after a subcutaneous challenge with viable P. gingiualis cells. Results: In CD4(+) T-cell-depleted mice (group 4), the DTH response and antigen-stimulated cell proliferation were significantly suppressed when compared to groups 2 and 3. Similarly, the levels of serum and splenic IgM, IgG, and all IgG subclass antibodies to P. gingiualis OMP were depressed. Delayed healing of P. gingivalis-induced lesions was also observed in the CD4(+) T-cell-depleted group. Conclusions: This study has shown that depletion of CD4(+) T cells prior to immunization with P. gingiualis OMP led to the suppression of both the humoral and cell-mediated immune response to this microorganism and that this was associated with delayed healing. These results suggest that the induction of the immune response to P. gingiualis is a CD4(+) T-cell-dependent mechanism and that CD4(+) T cells are important in the healing process.

A hedging point strategy - balancing effluent quality, economy and robustness in the control of wastewater treatment plants

An operational space map is an efficient tool to compare a large number of operational strategies to find an optimal choice of setpoints based on a multicriterion. Typically, such a multicriterion includes a weighted sum of cost of operation and effluent quality. Due to the relative high cost of aeration such a definition of optimality result in a relatively high fraction of the effluent total nitrogen in the form of ammonium. Such a strategy may however introduce a risk into operation because a low degree of ammonium removal leads to a low amount of nitrifiers. This in turn leads to a reduced ability to reject event disturbances, such as large variations in the ammonium load, drop in temperature, the presence of toxic/inhibitory compounds in the influent etc. Hedging is a risk minimisation tool, with the aim to "reduce one's risk of loss on a bet or speculation by compensating transactions on the other side" (The Concise Oxford Dictionary (1995)). In wastewater treatment plant operation hedging can be applied by choosing a higher level of ammonium removal to increase the amount of nitrifiers. This is a sensible way to introduce disturbance rejection ability into the multi criterion. In practice, this is done by deciding upon an internal effluent ammonium criterion. In some countries such as Germany, a separate criterion already applies to the level of ammonium in the effluent. However, in most countries the effluent criterion applies to total nitrogen only. In these cases, an internal effluent ammonium criterion should be selected in order to secure proper disturbance rejection ability.

Alterations in Plasmodium falciparum genotypes during sequential infections suggest the presence of strain specific immunity

Many of the asexual stage Plasmodium falciparum proteins that are the targets of host protective responses are markedly polymorphic. The full repertoire of diversity is not defined for any antigen. Most studies have focused on the genes encoding merozoite surface proteins 1 and 2 (MSP1, MSP2). We explored the extent of diversity of some of the less studied merozoite surface antigens and analyzed the degree of complexity of malaria field isolates by deriving nucleotide sequences of several antigens. We have determined the genotype of apical membrane antigen 1 (AMA1) in a group of 30 field samples, collected over 29 months, from individuals living in an area of intense malaria transmission in Irian Jaya, identifying 14 different alleles. AMA1 genotyping was combined with previously determined MSP2 typing. AMA1 had the greatest power in distinguishing between isolates but methodological problems, especially when mixed infections are present, suggest it is not an ideal typing target. MSP1, MSP3, and glutamate-rich protein genotypes were also determined from a smaller group of samples, and all results were combined to derive an extended antigenic haplotype. Within this subset of 10 patients, nine different genotypes could be discerned; however, five patients were all infected with the same strain. This strain was present in individuals from two separate villages and was still present 12 months later. This strain was predominant at the first time point but had disappeared at the fourth time point. This significant change in malaria genotypes could be due to strain-specific immunity developing in this population.

Quantification and stability of everolimus (SDZ RAD) in human blood by high-performance liquid chromatography-electrospray tandem mass spectrometry

We report here a validated method for the quantification of a new immunosuppressant drug, everolimus (SDZ RAD), using HPLC-tandem mass spectrometry. Whole blood samples (500 mul) were prepared by protein precipitation, followed by C-18 solid-phase extraction. Mass spectrometric detection was by selected reaction monitoring with an electrospray interface operating in positive ionization mode. The assay was linear from 0.5 to 100 mug/l (r(2) > 0.996, n = 9). The analytical recovery and inter-day imprecision, determined using whole blood quality control samples (n = 5) at 0.5, 1.2, 20.0, and 75.0 mug/l, was 100.3-105.4% and less than or equal to7.6%, respectively. The assay had a mean relative recovery of 94.8 +/- 3.8%. Extracted samples were stable for up to 24 h. Fortified everolimus blood samples were stable at -80 degreesC for at least 8 months and everolimus was found to be stable in blood when taken through at least three freeze-thaw cycles. The reported method provides accurate, precise and specific measurement of everolimus in blood over a wide analytical range and is currently supporting phase 11 and III clinical trials. (C) 2002 Elsevier Science B.V. All rights reserved.

Cold Storage Preservation and Warm Ischaemic Injury to Isolated Arterial Segments: Endothelial Cell Injury

Injury to endothelial calls is thought to be important to the development of the vascular lesion of chronic rejection. It was the aim of this study to develop a semiquantitative method to assess endothelial injury in arterial grafts and to document the injury produced by cold storage preservation and additional warm ischaemia. Twelve- and 24-h cold preservation of rat aortic segments, together with an additional 1 h of warm ischaemia, were assessed. Electron micrographs of representative endothelial cells were scored for cytoplasmic, nuclear and mitochondrial injury. The overall injury score was obtained by addition of the individual scores. Storage for up to 24 h in University of Wisconsin (UW) and Terasaki did not produce any injury. Twenty-four hours of storage in Euro-Collins resulted in endothelial cell death. Injury occurred after 12 h of storage in Ross, Collins and normal saline, and the injury increased following 24 h of storage. One hour of warm ischaemia did not increase the injury. Injury to endothelial cells varies with the preservation solution used and the time of cold storage, so that both the type of solution and the storage time should be taken into account in clinical studies looking at the influence of cold ischaemia time and graft outcome.

Selective ingestion of pelagic versus benthic algae by the cockle Cerastoderma edule (Linne, 1758)

The pre-ingestive selection of microphytobenthic algae by the cockle Cerastoderma edule was studied in comparison with diets containing the pelagic diatom Phaeodactylum tricomutum. Treatments with the different diets covered a range of seston concentrations and organic content similar to field conditions. Rejection rates of C. edule exposed to the different treatments were significantly correlated with the concentration of total particulate matter. No significant differences in total rejection rates were found between pelagic and benthic diets. Organic rejection rate was significantly correlated with particulate organic matter of the treatments and no significant differences were found between both diets. Selection efficiency was significantly correlated with particulate organic matter concentration in both diets and no significant differences were found between the diets. Analysis of the pseudofeces composition by flow cytometry from cockles exposed to a mixed diet of microphytobenthic algae and P. tricornutum, showed a preferential ingestion of the pelagic diatom. Benthic species, such as small pennates and Navicula sp., were preferentially ingested in comparison to larger microphytobenthic species. The largest microphytobenthic species, Cylindrotheca sp., was significantly rejected. In general, C. edule is an opportunistic filter feeder that takes advantage of both pelagic and benthic algal cells.

Induction of suppressor cells following mucosal presentation of Actinomyces viscosus in mice

Mucosal presentation of Actinomyces viscosus results in antigen-specific systemic immune suppression, known as oral tolerance. The aim of the present study was to determine the mechanism by which this oral tolerance is induced. DBA/2 mice were gastrically immunized with A. viscosus. Serum, Peyer's patch (PP) and spleen cells were transferred to syngeneic recipients which were then systemically challenged with the sameiA. viscosus strain. To determine antigen-specificity of cells from gastrically immunized mice, recipients which received immune spleen cells were also challenged with Porphyromonas gingivalis. One week after the last systemic challenge, the delayed type hypersensitivity (DTH) response was determined by footpad swelling and the level of serum IgG, IgA and IgM antibodies to A. viscosus or P. gingivalis measured by an ELISA. No suppression of DTH response or of specific serum antibodies was found in recipients which received serum from gastrically immunized mice. Systemic immune suppression to A. viscosus was observed in recipients which had been transferred with PP cells obtained 2 days but not 4 and 6 days after gastric immunization with A. viscosus. Conversely, suppressed immune response could be seen in recipients transferred with spleen cells obtained 6 days after gastric immunization. The immune response to P. gingivalis remained unaltered in mice transferred with A. viscosus-gastrically immunized cells. The results of the present study suggest that oral tolerance induced by A. viscosus may be mediated by antigen-specific suppressor cells which originate in the PP and then migrate to the spleen.

A naturally selected dimorphism within the HLA-B44 supertype alters class I structure, peptide repertoire, and T cell recognition

HLA-B*4402 and B*4403 are naturally occurring MHC class I alleles that are both found at a hi,,h frequency in all human populations, and vet they only differ by one residue on the alpha2 helix (B*4402 Aspl56-->B*4403 Leu156) CTLs discriminate between HLA-B*4402 and B*4403, and these allotypes stimulate strong mutual allogeneic responses reflecting their known barrier to hemopoeitic stem cell transplantation. Although HLA-B*4402 and B*4403 share >95% of their peptide repertoire, B*4403 presents more unique peptides than B*4402, consistent with the stronger T cell alloreactivity observed toward B*4403 compared with B*4402. Crystal structures of B*4402 and B*4403 show how the polymorphisin at position 156 is completely buried and yet alters both the peptide and the heavy chain conformation, relaxing ligand selection by B*4403 compared with B*4402. Thus, the polymorphism between HLA-B*4402 and B 4403 modifies both peptide repertoire and T cell recognition, and is reflected lit the paradoxically powerful alloreactivity that occurs across this minimal mismatch. The findings suggest that these closely related class I genes are maintained lit diverse human populations through their differential impact on the selection of peptide ligands and the T cell repertoire.

Cross-protective and Infection-Enhancing Immunity in Mice Vaccinated Against Flaviviruses Belonging to the Japanese Encephalitis Virus Serocomplex

The Japanese encephalitis virus serocomplex is a group of mosquito-borne flaviviruses that cause severe encephalitic disease in humans. The recent emergence of several members of this serocomplex in geographic regions where other closely related flaviviruses are endemic has raised urgent human health issues. Thus, the impact of vaccination against one of these neurotropic virus on the outcome of infection with a second, serologically related virus is unknown. We show here that immunity against Murray Valley encephalitis virus in vaccinated mice can cross-protect but also augment disease severity following challenge with Japanese encephalitis virus. Immunepotentiation of heterologous flavivirus disease was apparent in animals immunized with a 'killed' virus preparation when humoral antiviral immunty of low magnitude was elicited. (C) 2002 Elsevier Science Ltd. All rights reserved.

Sorte? Lógica? Modelos de significação e a noção de acaso de adultos alunos do Proeja

Esta tese se propôs investigar a lógica inferencial das ações e suas significações em situações que mobilizam as noções de composição probabilística e acaso, bem como o papel dos modelos de significação no funcionamento cognitivo de adultos. Participaram 12 estudantes adultos jovens da classe popular, voluntários, de ambos os sexos, de um curso técnico integrado ao Ensino Médio da Educação de Jovens e Adultos. Foram realizados três encontros, individualmente, com registro em áudio e planilha eletrônica, utilizando-se dois jogos, o Likid Gaz e o Lucky Cassino, do software Missão Cognição (Haddad-Zubel, Pinkas & Pécaut, 2006), e o jogo Soma dos Dados (Silva, Rossetti & Cristo, 2012). Os procedimentos da tarefa foram adaptados de Silva e Frezza (2011): 1) apresentação do jogo; 2) execução do jogo; 3) entrevista semiestruturada; 4) aplicação de três situações-problema com intervenção segundo o Método Clínico; 5) nova partida do jogo; e 6) realização de outras duas situações-problema sem intervenção do Método Clínico. Elaboraram-se níveis de análise heurística, compreensão dos jogos e modelos de significação a partir da identificação de particularidades de procedimentos e significações nos jogos. O primeiro estudo examinou as implicações dos modelos de significação e representações prévias no pensamento do adulto, considerando que o sujeito organiza suas representações ou esquemas prévios relativos a um objeto na forma de modelos de significação em função do grau de complexidade e novidade da tarefa e de sua estrutura lógico matemática, que evoluem por meio do processo de equilibração; para o que precisa da demanda a significar esse aspecto da 13 realidade. O segundo estudo investigou a noção de combinação deduzível evidenciada no jogo Likid Gaz, identificando o papel dos modelos de significação na escolha dos procedimentos, implicando na rejeição de condutas de sistematização ou enumeração. Houve predominância dos níveis iniciais de análise heurística do jogo. O terceiro estudo examinou a noção de probabilidade observada no jogo Lucky Cassino, no qual a maioria dos participantes teve um nível de compreensão do jogo intermediário, com maior diversidade de modelos de significação em relação aos outros jogos, embora com predominância dos mais elementares. A síntese das noções de combinação, probabilidade e acaso foi explorada no quarto estudo pelo jogo Soma dos Dados (Silva, Rossetti & Cristo, 2012), identificando-se que uma limitação para adequada compreensão das ligações imbricadas nessas noções é a implicação significante – se aleatório A, então indeterminado D (notação A  D), com construção de pseudonecessidades e pseudo-obrigações ou mesmo necessidades locais, generalizadas inapropriadamente. A resistência ou obstáculos do objeto deveria provocar perturbações, mas a estrutura cognitiva, o ambiente social e os modelos culturais, e a afetividade podem interferir nesse processo.

Síndrome de Sjögren: revisão de literatura e acompanhamento de um caso clínico

A síndrome de Sjögren é uma doença inflamatória sistêmica, de natureza auto-imune, caracterizada pela infiltração linfocitária progressiva de vários órgãos exócrinos e não exócrinos. Acomete preferencialmente as glândulas salivares e lacrimais determinando prejuízo estrutural e disfunção secretória destes órgãos. A produção de auto-anticorpos e a hipergamaglobulinemia policlonal indicam que anormalidades na imunidade humoral desempenham um papel importante na patogenia desta afecção e o seu diagnóstico é baseado na combinação de vários achados clínicos e laboratoriais. A proposta deste trabalho é apresentar um caso clínico de síndrome de Sjögren enfatizando a sua importância clínica e a necessidade do diagnóstico precoce na tentativa de melhorar a qualidade de vida dos pacientes acometidos.

O papel da imunofluorescência direta na fisiopatologia e no diagnóstico diferencial da estomatite aftóide recorrente

A estomatite aftóide recorrente é doença caracterizada por aparecimento periódico de aftas na mucosa oral, cuja etiologia e fisiopatologia não estão bem explicadas. Estudos recentes com imunofluorescência direta mostram resultados controversos. Alguns revelam que o distúrbio básico está relacionado à imunidade humoral, enquanto outros apontam alterações da imunidade celular. Formas atípicas de estomatite aftóide podem fazer diagnóstico diferencial com doenças vésico-bolhosas como pênfigo vulgar. OBJETIVO: Verificar a presença de imunecomplexos na mucosa de pacientes com estomatite aftóide e utilidade do método no diagnóstico diferencial com dermatopatias bolhosas. CASUÍSTICA E MÉTODO: 23 pacientes portadores de estomatite aftóide, de modo prospectivo, foram incluídos no estudo. Todos foram submetidos à biópsia de mucosa sob anestesia local para retirada de dois fragmentos. Um deles foi enviado para exame histológico e, outro, para ser realizada a imunofluorescência direta. RESULTADOS: As 23 amostras no exame histológico revelaram processo inflamatório inespecífico ulcerado. As amostras enviadas para imunofluorescência resultaram negativas e apenas uma revelou presença de complemento em membrana basal. CONCLUSÃO: Baseado em nossos resultados, concluímos que pacientes portadores de EAR não apresentam depósitos de imunecomplexos na mucosa da cavidade bucal e a imunofluorescência é útil no diagnóstico diferencial entre a doença e dermatopatias bolhosas.

Taking the "cross" out of cross-cultural transfer of management practice

Multi-national enterprises often attempt to replicate successful management practices in "foreign" environments. However, such practices may be ethnocentric because they fit the assumptions, behaviors, expectations, and values of the home cultural environment. Unless the underlying assumptions are shared, transfer to a differing environment may fail. Even if the focus is shifted from cultural differences to implementation, implementation approaches may also be criticized as ethnocentric for the same reasons. In this article, a non-ethnocentric model is expanded and used to test the portability of one management practice, performance appraisal, from the USA to Brazil. This "Test of Portability" may help managers understand which management practices are portable, and, perhaps even more valuable, provide a rationale for adaptation or rejection.