6,630 research outputs found
Selection bias: neighbourhood controls and controls selected from those presenting to a Health Unit in a case control study of efficacy of BCG revaccination.
BACKGROUND: In most case control studies the hardest decision is the choice of the control group, as in the ideal control group the proportion exposed is the same as in the population that produced the cases. METHODS: A comparison of two control groups in a case control study of the efficacy of BCG revaccination. One group was selected from subjects presenting to the heath unit the case attended for routine prevention and care; the second group was selected from the neighbourhood of cases. All Health Units from which controls were selected offered BCG revaccination. Efficacy estimated in a randomized control trial of BCG revaccination was used to establish that the neighbourhood control group was the one that gave unbiased results. RESULTS: The proportion of controls with scars indicating BCG revaccination was higher among the control group selected from Health Unit attenders than among neighbourhood controls. This excess was not removed after control for social variables and history of exposure to tuberculosis, and appears to have resulted from the fact that people attending the Health Unit were more likely to have been revaccinated than neighbourhood controls, although we can not exclude an effect of other unmeasured variables. CONCLUSION: In this study, controls selected from people presenting to a Health Unit overrepresented exposure to BCG revaccination. Had the results from the HU attenders control group been accepted this would have resulted in overestimation of vaccine efficacy. When the exposure of interest is offered in a health facility, selection of controls from attenders at the facility may result in over representation of exposure in controls and selection bias
Labels layout of cats and dogs food sold in Brazil and their national regulation adequacy
HISTÓRIA DA CIRURGIA DA CATARATA
The history of cataract surgery, like other medical procedures, presents a circular course, with repetition of previously reported and tested ideas. From the ruins of ancient Babylon arose the technique of crystalline aspiration, which lasted only a short time. The idea of dislocation of the crystalline to the vitreous chamber came from India and was used for more than 3000 years.During this period, there were several other sporadic and localized attempts to treat cataracts. It was only in 1750 that the French surgeon Jacques Daviel successfully performed the first planned extracapsular extraction. At first, the idea of opening the eye to remove the cataract was not well accepted due to the technical difficulties involved in the procedure. The intracapsular technique was easier and therefore started to gain adepts all over the world, becoming the model of choice by the beginning of the 20th century. Since 1950, the use of a microscope, of the extracapsular technique and of intraocular lenses has led to a new, constantly evolving era in the treatment of cataracts. A história da cirurgia da catarata, de forma semelhante a outros procedimentos em Medicina, apresenta um curso circular, com repetições de idéias já relatadas e introdução de outras novas. Das ruínas da Babilônia antiga, surgiu a técnica de aspiração do cristalino, que permaneceu por um curto período de tempo. A idéia do deslocamento do cristalino para câmara vítrea veio da Índia e foi utilizada por mais de 3000 anos. Durante este período, foram feitas diversas outras tentativas esporádicas e localizadas para tratamento da catarata. Somente em 1750, o cirurgião francês Jacques Daviel realizou, com sucesso, a primeira extração extracapsular planejada. A idéia de abrir o olho para remover a catarata não foi bem aceita inicialmente, devido às dificuldades técnicas impostas pelo procedimento na época. A técnica intracapsular era mais fácil e, por isso, começou a arrebanhar adeptos por todo o mundo, tornando-se o método de escolha a partir do início do século XX. A partir de 1950, a utilização do microscópio cirúrgico, juntamente com o desenvolvimento da técnica extracapsular, da facoemulsificação e das lentes intra-oculares, nos levaram a uma nova era no tratamento da catarata, um tempo em constante mudança
Produção de tomateiro orgânico irrigado por aspersão e gotejamento, em cultivo solteiro e consorciado com coentro.
O uso eficiente da água e a diversificação ambiental são fundamentais para o equilíbrio e a sustentabilidade dos sistemas orgânicos de produção de tomate. O presente estudo teve por objetivo avaliar a produção de tomate de mesa em cultivo solteiro e consorciado com coentro com irrigação por aspersão e gotejamento, em sistema orgânico. O experimento foi conduzido em área de produção orgânica no Distrito Federal. O delineamento foi blocos ao acaso, com tratamentos dispostos num arranjo fatorial 2 x 2 (dois sistemas de irrigação x dois sistemas de cultivo). Não houve interação significativa entre os fatores avaliados, assim como não houve efeito do sistema de cultivo sobre as variáveis avaliadas. Embora o ciclo do tomateiro irrigado por gotejamento tenha diminuído, a produtividade de frutos não foi afetada pelos sistemas de irrigação. A maior redução de estande verificada na aspersão foi compensada por um aumento no número de frutos por planta, sem variação na massa por fruto. O menor volume de solo explorado pelas raízes do tomateiro associado à maior incidência de traça-o-tomateiro (Tuta absoluta) e principalmente de oídio (Leveillula taurica) pode ter limitado a produtividade do tomateiro irrigado por gotejamento. A taxa de frutos podres na aspersão foi o dobro da verificada no sistema por gotejamento
Random X Inactivation and Extensive Mosaicism in Human Placenta Revealed by Analysis of Allele-Specific Gene Expression along the X Chromosome
Imprinted inactivation of the paternal X chromosome in marsupials is the primordial mechanism of dosage compensation for X-linked genes between females and males in Therians. In Eutherian mammals, X chromosome inactivation (XCI) evolved into a random process in cells from the embryo proper, where either the maternal or paternal X can be inactivated. However, species like mouse and bovine maintained imprinted XCI exclusively in extraembryonic tissues. The existence of imprinted XCI in humans remains controversial, with studies based on the analyses of only one or two X-linked genes in different extraembryonic tissues. Here we readdress this issue in human term placenta by performing a robust analysis of allele-specific expression of 22 X-linked genes, including XIST, using 27 SNPs in transcribed regions. We show that XCI is random in human placenta, and that this organ is arranged in relatively large patches of cells with either maternal or paternal inactive X. In addition, this analysis indicated heterogeneous maintenance of gene silencing along the inactive X, which combined with the extensive mosaicism found in placenta, can explain the lack of agreement among previous studies. Our results illustrate the differences of XCI mechanism between humans and mice, and highlight the importance of addressing the issue of imprinted XCI in other species in order to understand the evolution of dosage compensation in placental mammals
[1-(2,5-Dichloroanilino)-5-methyl-1H-1,2,3-triazol-4-yl]methanol
In the title compound, C10H10Cl2N4O, the hydroxy group and benzene ring are disposed to opposite sides of the central 1,2,3-triazolyl ring. The dihedral angle between the five- and six-membered rings is 87.51 (12)°, and the C-O bond of the hydroxy group lies almost normal to the plane of the 5-membered ring [N-C-C-O = -93.2 (2)°]. An intramolecular amino-N-H...Cl hydrogen bond is noted. In the extended structure, supramolecular layers in the ab plane are formed via hydroxy-O-H...N(ring) and amine-N-H...O(hydroxy) hydrogen bonds. The layers are connected along the c axis by [pi]-[pi] contacts between benzene rings [inter-centroid distance = 3.7789 (13) Å] and by C-Cl...[pi] interactions
Morbidade e sobrevida em AIDS avançada no Rio de Janeiro, Brasil
Opportunistic diseases (OD) are the most common cause of death in AIDS patients. To access the incidence of OD and survival in advanced immunodeficiency, we included 79 patients with AIDS treated at Hospital Evandro Chagas (FIOCRUZ) from September 1997 to December 1999 with at least one CD4 countAs doenças oportunistas (DO) são a causa mais comum de morte em pacientes com AIDS. Para acessar a incidência de DO e a sobrevida na imunodeficiência avançada, foram incluídos 79 pacientes com AIDS tratados no Hospital Evandro Chagas (FIOCRUZ) no período de Setembro de 1997 a Dezembro de 1999, com ao menos uma contagem de células CD
Hotelaria do Nordeste: no espelho da globalização
Análise da hotelaria nordestina, tendo em foco a tecnologia organizacional. Resgatam-se enfoques teóricos sobre tecnologia, incluindo autores preocupados com aspectos técnico-organizacionais além de sociopolíticos, bem como analisam-se dados secundários e primários. Destacam-se categorias de análise mais diretamente correlacionadas com a dinâmica da globalização e discutem-se as perspectivas do mercado e da qualidade total.This article analyses the technological organization of the northeastern Brazilian hotels. It emphasizes the analysis in correlation of the globalizationand it discuss the market perspectives and the total quality. It presents theorical aspects about hotel technology based primary and secundary data
Tympanic paragangliomas: case reports
Glomus tumors, also called paragangliomas, originate from nonchromaffin cells. The tumor is typically vascular and grows from capillary and pre-capillary vessels in-between epithelial cells. It is worth mentioning that the most common symptoms are pulsating tinnitus and hearing loss. Imaging studies (CT and MRI) are necessary for diagnosis. This paper shows five patients seen at the Hospital between 1995 and 2001 presenting glomus tympanicum. Women were most commonly affected, and the age ranged from 48 to 60 years (mean age of 50 years). The most common complaints were pulsating tinnitus and hearing loss. All patients were treated surgically.Os tumores glômicos, também chamados de paragangliomas, são formados por células não cromafins. O tumor é tipicamente vascular formado por vasos capilares e pré-capilares, interposto por células epiteliais. Para a sua abordagem inicial, deve-se ressaltar que os sintomas mais comumentes encontrados são o zumbido pulsátil e hipoacusia. A investigação através de imagem (tomografia computadorizada e ressonância magnética) se faz necessária. Apresentaremos neste trabalho 5 pacientes portadores de paragangliomas timpânicos atendidos no Hospital (de 1995 a 2001). O sexo predominante foi o feminino, a idade variou de 48 a 60 anos, com média de 50 anos. A queixa predominante foi o zumbido pulsátil e a hipoacusia. A conduta foi cirúrgica em todos os casos.Hospital Paulista de OtorrinolaringologiaUNIFESP-EPMUNIFESP, EPMSciEL
- …