Retención del conocimiento de estudiantes después de una capacitación teórico-laboratorial para detección de caries / Retenção de conhecimento de graduandos após 1. 5 ano de treinamento teórico-laboratorial para detecção de cárie / Students' knowledge retention after theoretical-laboratory training for caries detection in pediatric dentistry. 1. 5 Year-assessment

Este estudio evaluó la retención de conocimientos, de estudiantes de pregrado expuestos a una actividad educativa de detección de lesiones de caries. Estudiantes de Odontología de los últimos años fueron invitados a participar del estudio. Ellos recibieron la capacitación 1 año y medio antes. Para evaluar su retención de conocimientos se realizaron evaluaciones teóricas y prácticas para dimensionar los conocimientos, habilidades y actitudes de los estudiantes. Cada prueba se valoró entre 0 a 10. Análisis de regresión multinivel se usaron para ver la asociación entre el desempeño de los estudiantes y su percepción sobre la importancia de la actividad. Otras peculiaridades relacionadas al desempeño en temas específicos y diferentes tipos de evaluación también fueron estudiadas. 302 estudiantes fueron evaluados. En promedio, los estudiantes tuvieron una nota 6.68 para la teórica y 5.5 para la práctica, con desviación estándar de 1.88 y de 2.27, respectivamente. La percepción de los estudiantes sobre la actividad didáctica fue asociada a su desempeño. En la evaluación teórica, los estudiantes fueron peores al relacionar la condición clínica con la histológica (21% de aciertos) y al justificar su conducta frente a lesiones inactivas (36% de aciertos). En la evaluación práctica, el 70-90% de los estudiantes demostraron tener capacidad para detectar, valorar la actividad y tomar decisiones clínicas sobre lesiones iniciales y severas. Solo 50% detectó correctamente lesiones moderadas y 32% sabe su manejo. Concluimos que la retención de conocimientos de los alumnos en mediano plazo es moderada está dentro de lo esperado.

Este estudo avaliou a retenção de conhecimento, em médio prazo, de graduandos expostos a uma atividade educativa de detecção de cárie. Esta é uma parte do estudo multicêntrico IuSTC. Alunos dos últimos anos foram convidados a participar e passaram pela atividade. Foram avaliados quanto à retenção do conhecimento após 1,5 ano. Avaliações teóricas e práticas (pontuadas de 0 a 10) foram preparadas para avaliar conhecimento, habilidades e atitudes. Os escores foram definidos como desfechos. Análises de regressão multinível testaram a associação entre a performance dos alunos e sua percepção sobre a importância da atividade dentro do seu currículo. Particularidades relacionadas à performance em tópicos específicos e diferentes tipos de avaliação também foram explorados. 302 alunos participaram das avaliações. Em média, os alunos tiveram medias (desvio-padrão (DP), de 6,68 (1,88) teórica e 5,5 (2,27) prática. A percepção dos alunos esteve associada com sua performance. Na avaliação teórica, os alunos tiveram pior performance ao relacionar a condição clínica com a histológica (21% de acertos) ou em justificar a conduta frente a lesões inativas (36% de acertos). Na avaliação prática, 70-90% dos alunos demonstraram habilidade de detectar, avaliar atividade e tomar decisões clínicas frente a lesões iniciais e severas, enquanto 50% avaliaram adequadamente as lesões moderadas e apenas 32% demonstrou atitude correta do manejo. Em conclusão, a retenção do conhecimento dos alunos está dentro do esperado em uma análise de médio prazo. Para alguns tópicos (por exemplo, relacionados a prática e justificativa de atitudes), a performance dos alunos tende a ser pior.

This study aimed to evaluate undergraduate students' medium-term knowledge retention after a learning activity related to caries lesions detection. This study is part of the IuSTC multicenter study. Last-years dental students were invited to participate and were exposed to the teaching activity. Their knowledge retention after 1.5 year was assessed. Theoretical and practical tests (scored 0 to 10) were prepared to evaluate knowledge, abilities and attitudes The scores were set as outcomes. Multilevel regression analyses were used to assess the association between students' performance and his/her perception about the importance of such learning activity in curriculum. Particularities related to students' performance in specific topics and types of evaluations were also explored. 302 students participated. On average, students achieved 6.68 (SD=1.88) in theoretical and 5.5 (SD=2.27) in practical assessment. Student's perception was associated with their performance. In theoretical test, students performed worse (21% of correct answers) in linking clinical and histological condition or justifying clinical decision-making for inactive lesions (36% of correct answers). In the practical test, 70-90% demonstrated ability to detect, assess activity and make the decision about management of initial or severe lesions, while 50% of students could assess adequately moderate caries lesions and only 32% demonstrated correct attitude related to their management. Undergraduate students' knowledge retention related to the detection of caries lesions is moderate in a medium-term analysis. It is noted that for some topics (e.g. not related to practice/justification of attitudes), the students' performance tends to be worse.

How combining different caries lesions characteristics may be helpful in short-term caries progression prediction: model development on occlusal surfaces of primary teeth.

BACKGROUND: Few studies have addressed the clinical parameters' predictive power related to caries lesion associated with their progression. This study assessed the predictive validity and proposed simplified models to predict short-term caries progression using clinical parameters related to caries lesion activity status. METHODS: The occlusal surfaces of primary molars, presenting no frank cavitation, were examined according to the following clinical predictors: colour, luster, cavitation, texture, and clinical depth. After one year, children were re-evaluated using the International Caries Detection and Assessment System to assess caries lesion progression. Progression was set as the outcome to be predicted. Univariate multilevel Poisson models were fitted to test each of the independent variables (clinical features) as predictors of short-term caries progression. The multimodel inference was made based on the Akaike Information Criteria and C statistic. Afterwards, plausible interactions among some of the variables were tested in the models to evaluate the benefit of combining these variables when assessing caries lesions. RESULTS: 205 children (750 surfaces) presented no frank cavitations at the baseline. After one year, 147 children were reassessed (70%). Finally, 128 children (733 surfaces) presented complete baseline data and had included primary teeth to be reassessed. Approximately 9% of the reassessed surfaces showed caries progression. Among the univariate models created with each one of these variables, the model containing the surface integrity as a predictor had the lowest AIC (364.5). Univariate predictive models tended to present better goodness-of-fit (AICs < 388) and discrimination (C:0.959-0.966) than those combining parameters (AIC:365-393, C:0.958-0.961). When only non-cavitated surfaces were considered, roughness compounded the model that better predicted the lesions' progression (AIC = 217.7, C:0.91). CONCLUSIONS: Univariate model fitted considering the presence of cavitation show the best predictive goodness-of-fit and discrimination. For non-cavitated lesions, the simplest way to predict those lesions that tend to progress is by assessing enamel roughness. In general, the evaluation of other conjoint parameters seems unnecessary for all non-frankly cavitated lesions.

Association of Pathogenic Th17 Cells with the Disease Severity and Its Potential Implication for Biological Treatment Selection in Psoriasis Patients.

Psoriasis is an inflammatory autoimmune disease characterized by cutaneous lesions in plaques. It has been proposed that the immune response has a key role in the disease progression. Particularly, the Th17 cells through IL-17 can contribute to maintain the inflammatory process. The pathogenic Th17 phenotype has been described in human diseases and associated with high severity in inflammatory experimental models. However, it is not clear if the pathogenic phenotype could be present in the skin and peripheral blood as well as its possible association to severity in psoriasis. In the lesional skin, we found high infiltration of Th17 cells and the pathogenic phenotype, finding a correlation between the frequency of Th17 cells and the Psoriasis Area and Severity Index (PASI) score. In peripheral blood, we observed a pool of Th17 lymphocytes with potential to acquire pathogenic features. Interestingly, the percentage of pathogenic Th17 cells (CD4+ RORγt+ IFN-γ +) correlates with disease severity. Moreover, we distinguished three groups of patients based on their IL-17/IFN-γ production by Th17 lymphocytes, which seems to be related with a dynamic or stable potential to express these cytokines. Remarkably, we evaluated the cytokine production by Th17 cells as an immunological marker for the adequate selection of biologic therapy. We found that patients analyzed by this immunological approach and treated with antibodies against IL-17 and TNFα showed great improvement depicted by reduction in PASI and Dermatology Life Quality Index (DLQI) score as well as the percentage of Body Surface Area (BSA). Altogether, our results highlight the importance of the assessment of the pathogenic phenotype in Th17 cells as an immune personalized analysis with the potential to support the therapy choice in the clinical practice.

How can we associate an economic evaluation with a clinical trial?

Economic evaluations in Dentistry have been increasing in recent years. They are a relevant contribution if an economic issue exists. Knowing if a new intervention is an efficient way of allocating available (and scarce) resources (the concept of opportunity costs), a well-designed economic evaluation may be helpful. One option is to conduct a trial-based economic analysis, which extracts a considerable board of information from a trial. This approach produces a more controlled result since many sources of variations might be reduced. On the other hand, some aspects could not be predicted directly from the trial or even extrapolated. Thus, combining model-based analysis may be an idea. In this paper, we intended to discuss important aspects to be considered by researchers in further economic evaluations. This paper will be systematically divided into sessions related to the study design as time horizon and perspective, health effects, costs, and data analysis. In the end, we expect the reader could be able to plan a trial-based economic evaluation, which should be a careful, meticulous, quite laborious and especially transparent process.

O selamento é uma alternativa as restaurações para lesões de cárie moderada na superfície oclusal de dentes decíduos? / Is sealing an alternative to restoration for moderate caries lesions on occlusal surfaces in primary teeth?

Na Odontologia, apesar do conceito da mínima intervenção, uma proporção significativa de dentistas ainda intervém de maneira invasiva em lesões de cárie, clinicamente ou radiograficamente confinadas ao esmalte, ou até minimamente em dentina. Algumas lesões não francamente cavitadas apresentam um risco de progressão maior que lesões iniciais, merecendo atenção especial no controle de sua progressão. O objetivo desse trabalho foi investigar o risco de progressão de lesões de cárie moderada (ICDAS 3-4) e avaliar se o selamento pode ser uma alternativa as restaurações no controle de em superfícies oclusais de molares decíduos. Este volume apresenta um compilado de uma revisão sistemática e um ensaio clínico randomizado associado a uma avaliação econômica cujas redações foram orientados pelas recomendações dos guias PRISMA, CONSORT e CHEERS. Realizamos uma revisão sistemática, cuja pesquisa bibliográfica buscou avaliar o impacto das características clínicas e radiográficas das lesões de cárie na sua progressão em dentes decíduos. Assim, foi possível observar que lesões apresentando cavidades mesmo que clinicamente confinadas em esmalte ou sombra, apresentavam maior risco de progressão. Adicionalmente, um ensaio clínico randomizado de não inferioridade foi delineado, para avaliar a longevidade (não necessidade de reintervenções) do selamento de lesões de cárie moderada com cimento de ionômero de vidro como alternativa as restaurações com o mesmo material. Uma avaliação econômica foi associada a este ensaio clínico para avaliar a custo-efetividade da implementação desse tratamento alternativo. Uma perspectiva societal e um horizonte temporal de 2 anos. No estudo clínico, crianças entre 3 a 6 anos, que apresentaram superfícies oclusais classificadas como escores 3 ou 4 do ICDAS foram randomizadas. As crianças foram tratadas e reavaliados bianualmente por 24 meses por 2 examinadores treinados. O desfecho primário foi a necessidade de reintervenção nos dentes inicialmente tratados (falhas que demandassem a reparo, substituição dos selantes e restaurações, bem como progressão de lesões que demandassem nova restauração). Os custos dos tratamentos e reintervenções foram calculados para se avaliar a razão de custo-efetividade incremental para avaliar a eficiência da substituição da restauração pelos selantes em lesões de cárie moderadas. Para isso, efeitos de saúde centrados no paciente (aceitabilidade dos tratamentos usando a escala da Wong-Baker) e no profissional (ausência de progressão de cárie) foram usados. Após 2 anos de acompanhamento, o selamento de lesões de cárie moderada com cimento de ionômero de vidro demandou maior número de substituições que as restaurações. Por outro lado, não houve diferença quanto à progressão de cárie. Quando a visão do profissional foi colocada, os selantes ofereceram uma probabilidade de 30% de ser uma ótima opção custoefetiva em alternativa à restauração para evitar progressão de cárie, enquanto usando a aceitabilidade pela criança, essa probabilidade aumentou para 50%. Assim, considerando que as lesões moderadas realmente apresentam um alto risco de progressão, selar pode ser uma alternativa à restauração para controlar esse tipo de lesão, mas um maior número de reintervenções pode ser necessário. Por outro lado, é importante considerar que esse tratamento alternativo pode beneficiar grupos diferentes de formas diferentes e ainda, esse benefício pode variar com a perspectiva ouvida para a tomada de decisão (se é centrada no paciente ou no profissional). A investigação futura sobre essas diferenças faz-se ainda necessária.

How can we associate an economic evaluation with a clinical trial?

Abstract Economic evaluations in Dentistry have been increasing in recent years. They are a relevant contribution if an economic issue exists. Knowing if a new intervention is an efficient way of allocating available (and scarce) resources (the concept of opportunity costs), a well-designed economic evaluation may be helpful. One option is to conduct a trial-based economic analysis, which extracts a considerable board of information from a trial. This approach produces a more controlled result since many sources of variations might be reduced. On the other hand, some aspects could not be predicted directly from the trial or even extrapolated. Thus, combining model-based analysis may be an idea. In this paper, we intended to discuss important aspects to be considered by researchers in further economic evaluations. This paper will be systematically divided into sessions related to the study design as time horizon and perspective, health effects, costs, and data analysis. In the end, we expect the reader could be able to plan a trial-based economic evaluation, which should be a careful, meticulous, quite laborious and especially transparent process.

Intestinal Microbiota Influences Non-intestinal Related Autoimmune Diseases.

The human body is colonized by millions of microorganisms named microbiota that interact with our tissues in a cooperative and non-pathogenic manner. These microorganisms are present in the skin, gut, nasal, oral cavities, and genital tract. In fact, it has been described that the microbiota contributes to balancing the immune system to maintain host homeostasis. The gut is a vital organ where microbiota can influence and determine the function of cells of the immune system and contributes to preserve the wellbeing of the individual. Several articles have emphasized the connection between intestinal autoimmune diseases, such as Crohn's disease with dysbiosis or an imbalance in the microbiota composition in the gut. However, little is known about the role of the microbiota in autoimmune pathologies affecting other tissues than the intestine. This article focuses on what is known about the role that gut microbiota can play in the pathogenesis of non-intestinal autoimmune diseases, such as Grave's diseases, multiple sclerosis, type-1 diabetes, systemic lupus erythematosus, psoriasis, schizophrenia, and autism spectrum disorders. Furthermore, we discuss as to how metabolites derived from bacteria could be used as potential therapies for non-intestinal autoimmune diseases.

Impact of Tooth Loss on Quality of Life

Objective: To evaluate the impact of tooth loss on the quality of life of patients at the Cesmac University Center. Material and Methods: A cross-sectional study was performed, whose sample was composed of 224 volunteers from various health units of the selected health service with at least 12 years of age and one missing tooth. Quality of Life (QOL) was assessed using the Oral Health Impact Profile (OHIP -14) and tooth loss was assessed with the dental chart. A structured interview that assessed the socio-economic condition of the individual was also applied. For interpretation of the OHIP-14, values were assigned using the multiplicative method: 0-3 points = no impact; 3.01 to 6 points = low impact; 6.01 to 10 points = moderate impact; and> 10.01 points = high impact. All volunteers received guidance on oral health and, when necessary, a referral to the dental care provided by this institution was performed. Results: The mean OHIP ranged from no impact (30.9%) to high impact (27.8%). The correlation between the number of missing teeth and QOL scores was statistically significant (p <0.05), as well as the correlation between number of missing teeth and age of volunteers (p <0.0001). The dimensions of the OHIP-14 that showed the most influenced domains were pain, psychological discomfort, psychological disability. Conclusion: Increasing age has shown influence on tooth and tooth loss affected the QOL of volunteers. QOL may be influenced by other factors such as loss of anterior teeth and schooling.

Impact of Hispanic ethnic concentration and socioeconomic status on obesity prevalence in Texas counties.

The purpose of this study is to determine whether Hispanic ethnic concentration is associated with a higher prevalence of obesity and, if this relationship exists, whether it is affected by the socioeconomic environment. The study uses the Texas Behavioral Risk Factor Surveillance System (BRFSS) linked to 2000 census data to access the relationship between prevalence of obesity, Hispanic ethnic concentration, poverty and level of education at a county-level. The findings suggest that the association of Hispanic ethnic concentration and obesity varies by socioeconomic environment. Although little influence was observed for % poverty, the relationship between Hispanic ethnic concentration and obesity differed by county-level educational attainment. High proportion of residents with a bachelor's degree is associated with a low prevalence of obesity; counties with both high % Hispanic and high % with Bachelor's degrees had the lowest prevalence of obesity. Our results suggest that promoting and improving education, perhaps including training on healthful living, may serve as an effective means of curbing current obesity trends and associated health problems in Hispanic and possibly other ethnic communities.

Repercussão de um protocolo fisioterapêutico intradialítico na funcionalidade pulmonar, força de preensão manual e qualidade de vida de pacientes renais crônicos / Repercussion of physiotherapy intradialytic protocol for respiratory muscle function, grip strength and quality of life of patients with chronic renal diseases

INTRODUÇÃO: A doença renal crônica consiste na perda lenta, progressiva e irreversível da função renal. É considerada um problema social e economico, pois está relacionada a inúmeras doenças associadas, bem como a altos gastos em saúde pública. Sabe-se que os pacientes dialíticos passam por longos períodos de restrição da atividade física repercutindo em disfungoes nos mais diversos sistemas e na qualidade de vida (QV). OBJETIVO: Verificar os efeitos de uma intervenção fisioterapêutica nos pacientes em hemodiálise para: função da musculatura respiratória, força de preensão manual e QV. METODOLOGIA: Estudo experimental, não randomizado, quantitativo e qualitativo; amostra de 13 pacientes, 43,69 ± 9,28 anos, submetidos à hemodiálise na Santa Casa de Diamantina/MG, selecionados por conveniência. Todos realizaram avaliação das pressões respiratórias máximas (PImáx e PEmáx) e do pico de fluxo expiratório (PFE), antes e após a fisioterapia que consistiu de três sessões semanais, durante 2 meses de: exercícios para membros superiores, com técnica de FNP e respiração diafragmática; exercícios de fortalecimento para membros inferiores e exercícios com bola exercitadora para preensão manual. O tratamento estatístico foi realizado através do teste t de Student com valor de significância em p < 0,05. RESULTADOS: As médias respectivamente das variáveis pré- e pós-intervenção foram PI , (97,69 ± 28,3 cmH2O e 98,46 ± 23,399ªdriH2O) p = 0,93; PEmáx (83,07 ± 31,19 cmH2O e 88,46 ± 14,05 cmH2O) p = 0,46 e PFE (375,38 ± 75,23 L/min e 416,15 ± 57,37 L/min) p = 0,02. A media do dinamometro pré-intervenção: 57,23 ± 17,39 kgf e pósintervenção: 56,61 ± 16,09 kgf. No SF-36, que avalia QV, observou-se melhora dos oito domínios, exceto do item 'vitalidade'. De todas as variáveis mensuradas, somente o PFE mostrou-se estatisticamente significante. CONCLUSÃO: O protocolo fisioterapêutico proposto não promoveu melhoras expressivas, do ponto de vista estatístico, nas variáveis analisadas em pacientes submetidos à hemodiálise, justificando-se em parte ao número pequeno da amostra, tempo do protocolo e intervenções propostas.

INTRODUCTION: Chronic kidney disease consists in the slow, progressive and irreversible loss in renal function and it is considered a social and economic problem worldwide, since it is linked to numerous diseases, as well as to higher public health spending. It is known that dialysis patients undergo a long period of restricted physical activity reflects in dysfunctions in various organical systems and in the quality of their lives. OBJECTIVE: To verify the results of physical therapy intervention in patients on hemodialysis, for respiratory muscle function, grip strength and quality of life. METHODOLOGY: Experimental, nonrandomized, quantitative and qualitative of a sample of 13 patients, 43.69 ± 9.28 years, on hemodialysis in the hospital Santa Casa de Diamantina/MG, selected by convenience. All patients were evaluated for maximal respiratory pressures (PImax e PEmax ) and peak expiratory flow (PFE), before and after physiotherapy, which consisted of 3 sessions per week for a period of 2 months weeks: exercises for upper limbs, with technique PNF and breathing diaphragmatic; strengthening exercises for lower limbs and use of exerciser ball. Statistical analysis was performed using the student-t test and significance value at p < 0.05. RESULTS: Respective means for the variables before and after intervention were: PImáx (97.69 ± 28.3 cmH2O e 98.46 ± 23.39 cmH2O) p = 0.93; PEmáx (83.07 ± 31.19 cmH2O e 88.46 ± 14.0 cmH2O) p = 0.46 e PF (375.38 ± 75.23 L/min e 416.15 ± 57.37 L/min) p = 0.02. The dynamometer average pre intervention was: 57.23 ± 17.39 kgf and post intervention: 56.61 ± 16.09 kgf. In the SF-36, which evaluates the quality of life, improvement was observed in the eight domains, except the item 'vitality'. Of all the variables measured only the PFE was statistically significant. CONCLUSION: The proposed physical therapy protocol did not promote significant improvements in those variables, the statistical point, explaining in part the small sample size, time of protocol and proposed interventions.

Repercussion of physiotherapy intradialytic protocol for respiratory muscle function, grip strength and quality of life of patients with chronic renal diseases.

INTRODUCTION: Chronic kidney disease consists in the slow, progressive and irreversible loss in renal function and it is considered a social and economic problem worldwide, since it is linked to numerous diseases, as well as to higher public health spending. It is known that dialysis patients undergo a long period of restricted physical activity reflects in dysfunctions in various organical systems and in the quality of their lives. OBJECTIVE: To verify the results of physical therapy intervention in patients on hemodialysis, for respiratory muscle function, grip strength and quality of life. METHODOLOGY: Experimental, nonrandomized, quantitative and qualitative of a sample of 13 patients, 43.69 ± 9.28 years, on hemodialysis in the hospital Santa Casa de Diamantina/MG, selected by convenience. All patients were evaluated for maximal respiratory pressures (PI(max) e PE(max) ) and peak expiratory flow (PFE), before and after physiotherapy, which consisted of 3 sessions per week for a period of 2 months weeks: exercises for upper limbs, with technique PNF and breathing diaphragmatic; strengthening exercises for lower limbs and use of exerciser ball. Statistical analysis was performed using the student-t test and significance value at p < 0.05. RESULTS: Respective means for the variables before and after intervention were: PImáx (97.69 ± 28.3 cmH2O e 98.46 ± 23.39 cmH2O) p = 0.93; PEmáx (83.07 ± 31.19 cmH(2)O e 88.46 ± 14.0 cmH(2)O) p = 0.46 e PF (375.38 ± 75.23 L/min e 416.15 ± 57.37 L/min) p = 0.02. The dynamometer average pre intervention was: 57.23 ± 17.39 kgf and post intervention: 56.61 ± 16.09 kgf. In the SF-36, which evaluates the quality of life, improvement was observed in the eight domains, except the item 'vitality'. Of all the variables measured only the PFE was statistically significant. CONCLUSION: The proposed physical therapy protocol did not promote significant improvements in those variables, the statistical point, explaining in part the small sample size, time of protocol and proposed interventions.

Anxiety influences children's memory for procedural pain.

OBJECTIVE: To examine the effects of temperament and trait anxiety on memory for pain. METHODS: Three dimensions of temperament, as well as trait anxiety, were assessed in 36 children (five to 12 years of age) undergoing dental procedures; after the procedure, the children provided pain ratings. Following a six- to eight-week delay, the children reported how much pain they remembered. RESULTS: Most children (85%) accurately recalled their pain. Temperament had no significant effect, but trait-anxious children showed a greater likelihood of recalling more pain than they initially reported, suggesting that they may negatively distort recollections of painful experiences. CONCLUSIONS: When treating children, in particular trait-anxious children, clinicians should consider what children remember as part of pain management intervention.

Quartas saudáveis: travessias de um projeto de educação popular em saúde desenvolvido em uma ONG na ilha de Caratateua, Belém/PA / Healthy Wednesdays - The Passages of a Popular Health Education Project Developed in an NGO of Caratateua Island, Belem, Para

Em 2003, a ONG Instituto Saber Ser Amazônia Ribeirinha (ISSAR), implantou o Programa Quartas Saudáveis visando contribuir com a qualidade de vida da população da ilha de Caratateua, Belém, PA. Em 2004 o programa foi fortalecido e ampliado em um Projeto de Extensão da Universidade do Estado do Pará (UEPA). O projeto sinaliza uma concepção de educação ambiental bem como destaca o espaço alternativo oferecido pelas ONGs para tais atividades. Destacam-se as travessias do projeto entre 2003 e 2004.

Necrotic cell injury in the preterm and near-term ovine fetal brain after intermittent umbilical cord occlusion.

OBJECTIVE: This study was undertaken to determine the extent of necrotic cell death as a measure of neurologic injury in the preterm and near-term ovine fetal brain in response to intermittent umbilical cord occlusion (UCO) with severe, but limited hypoxia and no cumulative acidosis to ensure longer-term survival. STUDY DESIGN: Fetal sheep (control and experimental groups at 0.75 and 0.90 of gestation) were studied over 4 days with UCOs performed in the experimental group animals by complete inflation of an occluder cuff for 90 seconds every 30 minutes for 3 to 5 hours each day. Animals were then euthanized and the fetal brain perfusion-fixed and prepared for subsequent histology and assessment of necrotic cell injury by using standard staining with hematoxylin and eosin (H&E), and with a novel fluorescent marker, Fluoro-Jade B, that targets degenerating neurons. RESULTS: In both preterm and near-term animal groups, UCO caused a large decline in arterial Po(2) (to approximately 7 mm Hg), a modest decline in pH (to approximately 7.30), and a modest rise in Pco(2) (to approximately 61 mm Hg) (all P<.01), but with a return to control values after the occluder release and no cumulative acidosis over each day of study. Overall, very low levels of H&E-stained necrotic-appearing cells and Fluoro-Jade B-stained positive cells were observed across all brain regions studied with values not significantly different from zero, excepting that for the gray matter of the preterm control (by H&E staining), preterm and near-term cord occlusion (by H&E and Fluoro-Jade B staining), and the thalamus of the near-term cord occlusion (by H&E staining) animals. Although there were no differences in the levels of H&E-stained necrotic-appearing cells and Fluoro-Jade B-stained positive cells between respective control and cord occlusion group animals for most of the brain regions studied, a significant increase in Fluoro-Jade B-stained positive cells was observed in the gray matter of both the preterm and near-term cord occlusion animals (P<.05). CONCLUSION: Intermittent cord occlusion insult with severe but limited fetal hypoxemia and no cumulative acidosis, was generally well tolerated in both the preterm and near-term animal groups as assessed by measures of necrotic cell injury throughout the brain with minimal evidence for such. However, compensatory mechanisms which are protective for the brain may become limited with repetitive hypoxia insult over time as suggested by the low level of Fluoro-Jade B-stained positive cells noted in the gray matter tissues for both occlusion groups.

Structural proteins during brain development in the preterm and near-term ovine fetus and the effect of intermittent umbilical cord occlusion.

OBJECTIVE: The purpose of this study was to determine the immunoreactivity of selected structural proteins in the preterm and near-term ovine fetal brain and the response to intermittent umbilical cord occlusion as a measure of altered cellular growth. The intermediate filament proteins nestin, vimentin, and glial fibrillary acidic protein was used as markers for astroglial maturation and astrogliosis, and myelin basic protein as a marker for oligodendrocytes and myelin formation. STUDY DESIGN: Fetal sheep (control and experimental groups at 0.75 and 0.90 of gestation) were studied over 4 days; umbilical cord occlusion was performed in the experimental group by complete inflation of an occluder cuff for 90 seconds every 30 minutes for 3 to 5 hours each day. Animals were then killed, and the fetal brain was perfusion fixed and processed for immunohistologic examination of the gray and white matter. Immunoreactivity was quantified with an image analysis system and expressed as the fractional area positive stain for each protein. RESULTS: In both preterm and near-term animal groups, umbilical cord occlusion caused a large decline in arterial Po(2) (to approximately 7 mm Hg), a modest decline in pH (to approximately 7.30), and a modest rise in Pco(2) (to approximately 61 mm Hg; all P <.01), with a return to control values after the occluder release and no cumulative acidosis over each day of study. Vimentin and glial fibrillary acidic protein immunoreactivity showed reciprocal changes, with vimentin decreased and glial fibrillary acidic protein increased in both the gray and white matter of the control group from 0.75 to 0.90 of gestation, which can be attributed to the transition of radial glia into mature astrocytes. Myelin basic protein immunoreactivity increased approximately 3-fold in the white matter of the control group with advancing gestation, which likely reflected active oligodendrocyte differentiation and increased myelination at this time of development. Intermittent umbilical cord occlusion over 4 days resulted in an approximately 60% decrease in nestin, vimentin, and glial fibrillary acidic protein immunoreactivity, which was qualitatively similar for both the gray and white matter and likely indicative of altered protein synthesis and/or degradation, but only in the preterm group and with no change in myelin basic protein immunoreactivity. CONCLUSION: There is considerable change in the immunoreactivity of structural proteins within the ovine fetal brain over the latter part of gestation and consistent with a high rate of protein turnover, as previously reported. Intermittent umbilical cord occlusion as studied with minimal evidence for necrotic cell injury appears capable of altering selected protein synthesis/degradation, more so in younger animals when protein turnover is higher, which might then impact on the brain's development.