ABSTRACT
BACKGROUND: Birefringence can reveal much of the morphology, molecular order, heterogeneity of fiber orientation, and nonlinear optical properties of biopolymers such as collagen. However, the detailed characterization of skin collagen fibers using optical anisotropy methods remains elusive. A clear understanding of collagen fiber organization in skin tissues may be important in the interpretation of their structural-functional relationships under normal and pathological conditions. In this study, fiber orientation in collagen bundles (CBs) and their supramolecular organization were examined in rat skin using polarization microscopy and image analysis. METHODOLOGY/PRINCIPAL FINDINGS: Image variations with rotation of the microscope stage and selection of the in-depth focus plane were investigated in unstained sections of varying thicknesses from rat skin fragments. Total birefringence (image analysis) and form and intrinsic birefringence (Sénarmont's method) were estimated. Based on the birefringent images, CBs were found to contain intercrossing points with a twisted helical distribution of collagen fibers (chiral elements) and frequently presented circular structures. Collagen fibers were observed to extend from the surface level to deeper planes, creating a 3D-network of oriented intertwined CBs. At least three levels of birefringent brilliance intensity were revealed by image analysis, indicating a heterogeneous spatial organization of the CBs. Slight differences in optical retardations were found for CBs immersed in some of the fluids used in a comparison of 170- and 240-day old rats. CONCLUSION/SIGNIFICANCE: Polarization microscopy studies provide detailed high-quality structural information on rat skin CBs. A 3D-network structure based on image analysis and birefringence compensation for collagen fibers is suggested for CBs. Form and intrinsic birefringence evaluation can reveal differences in the rat skin associated with age at the levels of collagen fiber crystallinity and macromolecular organization. These findings may inspire future studies of the feedback mechanisms by which spatial, bioelectrical and biomechanical information is transmitted from CBs to skin cells.
Subject(s)
Collagen/chemistry , Skin/ultrastructure , Animals , Anisotropy , Extracellular Matrix/chemistry , Extracellular Matrix/ultrastructure , Image Processing, Computer-Assisted , Male , Microscopy, Polarization , Rats , Skin/chemistryABSTRACT
Introdução - Amamentar é uma prática essencial e exclusiva para o crescimento e desenvolvimento da criança nos seis primeiros meses de vida. Uma nutrição adequada oferece de forma qualitativa e quantitativa todos os nutrientes necessários para a criança. O objetivo foi o de realizar o levantamento das necessidades de conhecimento das mães em relação à alimentação dos seus filhos; desenvolver um instrumento educativo que possa ser utilizadas pelas mesmas. Material e Métodos -Pesquisa quantitativa exploratória realizada em um município do interior do Estado de São Paulo, em 2008, composta por 50 mães de crianças entre 0 a 2 anos de idade. Utilizou-se um questionário elaborado pelos pesquisadores validado por cinco juízes. Resultados - Os dados relevantesforam: 35 (70%) permanecem o dia todo com a criança; 45 (90%) receberam orientações sobre aleitamento materno e 33 (66%) sobre alimentação adequada no primeiro ano de vida da criança; 20(40%) foram orientadas pelos médicos, 14 (28%) pelos enfermeiros e 9 (18%) por médicos e enfermeiros. As crianças que receberam aleitamento exclusivo encontram-se acima do percentil 50 (50/50%) fato que não ocorreu para as crianças que receberam outro tipo de aleitamento. A maioria das mães 24 (8%) consideram correto oferecer liquido, 21 (42%) consideram correto oferecer frutase 1 (2%) considera correto oferecer alimentos sólidos antes do sexto mês. Conclusão - Os hábitos alimentares são influenciados pelos conhecimentos das mães. Portanto, é necessário o aprimoramento da equipe de saúde para melhor atuação com a clientela e a construção de novos instrumentos para que se invista em educação em nutrição infantil e possa obter resultados satisfatórios.
Introduction -Breastfeeding is an exclusive and essential practice to the growth and developmentof a child during the six first months of life. Because apropriate food offers in qualitative and quantitative ways all the required nutrients for a child. The objective was to do a survey of the mother's knowledge needs regarding the their children's food and develop an educational tool containing useful information which can be used by themselves. Material and Methods - Quantitative explorative survey performed in Campinas. The sample consisted of 50/100% mothers of children. A questionnaire developed by the researchers and validated by five judges was used. The data were analyzed by descriptive analysis and Pearson's Chi-Squared tests. Results - The relevant data were: 35/70% remain all day long with the child; 45/90% received guidance about breastfeeding and 33/66% about food; 20/40% received doctor's guidance, 14/28% received nurse's guidanceand 9/18% received doctor's and nurse's guidance. The children which had exclusive breastfeeding are in general above 50 percent (50/50%) a fact that did not occurred for children which had another kind of breastfeeding. The majority of the mothers 24/48% considered correct to offer liquid, 21/42% considered correct to offer fruits and 1/2% considered correct to offer solid food before the 6th month. Conclusion - The dietary habits also depend on the knowledge that mothers have in relation to them. Therefore, the improvement of the health care team for better performance with clients and the construction of new tools for education on infant nutrition.
