RESUMO
BACKGROUND: Skin expansion is a physiological process that is defined as the ability of the human skin to increase its superficial area in response to stress or to a given deformation. Skin expanders are silicon bags that are implanted underneath the skin. Because the skin presents creep or relaxation, the resulting stress decreases after a time due to the imposed deformation. Skin expansions are used to reconstruct burned areas and breasts after a mastectomy or to hide scars. PURPOSE: The question that constantly arises during skin expansion is whether it creates a sufficient amount of skin or, in other words, whether the achieved expansion is sufficient to resurface the defect. These questions are answered with information about how much new tissue is required to achieve the reconstruction in a given context and calculating the required tissue (surface area) in relationship with the volume infiltrated. METHOD: Surface formulas for round and rectangular, and finite elements method for crescent skin expanders are used to calculate the relation between infiltrated volume and surface area. Those results were corrected or validated by an experimental work using 3D scanners to calculate the relation between surface area and internal volumes for the three types of expanders in question. RESULTS: The research provides information to determine the type, number, and volume of skin expanders necessary to obtain an extra amount of skin to repair a specific medical condition and to determine the amount of skin obtained even in cases when the expansion does not come to term. SYMBOLS: fci, Correcting factor, which corrects the mathematical formulas using the experimental results, for i skin expander; i, geometry of the expander, round (c), rectangular (r), or crescent (cresc/cr); Sd , surface of the defect; Sds , surface area of the donor site; Sfi, surface area obtained using a mathematical calculation for the i skin expander; S¯fi, surface area obtained experimentally for the i skin expander; Sfi∗, corrected surface area obtained using a mathematical calculation for the i skin expander corrected by the correcting factor; S¯fi∗∗ extra flap of skin obtained by expansion for the i skin expander; Vii, internal volume infiltrated in the i skin expander; Vni, nominal internal volume of the i skin expander.
Assuntos
Procedimentos Cirúrgicos Dermatológicos/instrumentação , Procedimentos Cirúrgicos Dermatológicos/métodos , Modelos Teóricos , Fenômenos Fisiológicos da Pele , Dispositivos para Expansão de Tecidos , Expansão de Tecido/instrumentação , Expansão de Tecido/métodos , Força Compressiva , Simulação por Computador , Desenho Assistido por Computador , Módulo de Elasticidade/fisiologia , Análise de Falha de Equipamento , Humanos , Desenho de Prótese , Implantação de Prótese/métodos , Estresse Mecânico , Resistência à Tração/fisiologiaRESUMO
Sugarcane is an economically important culture in Brazil. Endophytic bacteria live inside plants, and can provide many benefits to the plant host. We analyzed the bacterial diversity of sugarcane cultivar RB-72454 by cultivation-independent techniques. Total DNA from sugarcane stems from a commercial plantation located in Paraná State was extracted. Partial 16S rRNA genes were amplified and sequenced for library construction. Of 152 sequences obtained, 52% were similar to 16S rRNA from Pseudomonas sp, and 35.5% to Enterobacter sp. The genera Pantoea, Serratia, Citrobacter, and Klebsiella were also represented. The endophytic communities in these sugarcane samples were dominated by the families Enterobacteriaceae and Pseudomonadaceae (class Gammaproteobacteria).
Assuntos
Endófitos/genética , Enterobacteriaceae/genética , Pseudomonadaceae/genética , Saccharum/microbiologia , Técnicas de Cultura , Tipagem Molecular , Filogenia , RNA Bacteriano/genética , RNA Ribossômico 16S/genéticaRESUMO
Sugarcane is an important agricultural product of Brazil, with a total production of more than 500 million tons. Knowledge of the bacterial community associated with agricultural crops and the soil status is a decisive step towards understanding how microorganisms influence crop productivity. However, most studies aim to isolate endophytic or rhizosphere bacteria associated with the plant by culture-dependent approaches. Culture-independent approaches allow a more comprehensive view of entire bacterial communities in the environment. In the present study, we have used this approach to assess the bacterial community in the rhizosphere soil of sugarcane at different times and under different nitrogen fertilization conditions. At the high taxonomic level, few differences between samples were observed, with the phylum Proteobacteria (29.6 percent) predominating, followed by Acidobacteria (23.4 percent), Bacteroidetes (12.1 percent), Firmicutes (10.2 percent), and Actinobacteria (5.6 percent). The exception was the Verrucomicrobia phylum whose prevalence in N-fertilized soils was approximately 0.7 percent and increased to 5.2 percent in the non-fertilized soil, suggesting that this group may be an indicator of nitrogen availability in soils. However, at low taxonomic levels a higher diversity was found associated with plants receiving nitrogen fertilizer. Bacillus was the most predominant genus, accounting for 19.7 percent of all genera observed. Classically reported nitrogen-fixing and/or plant growth-promoting bacterial genera, such as Azospirillum, Rhizobium, Mesorhizobium, Bradyrhizobium, and Burkholderia were also found although at a lower prevalence.
Assuntos
Biota , Bactérias/genética , Rizosfera , /genética , Microbiologia do Solo , Saccharum/microbiologia , Brasil , Bactérias/classificação , DNA Bacteriano/genética , Fertilizantes , Nitrogênio , Filogenia , Raízes de Plantas/microbiologiaRESUMO
Sugarcane is an important agricultural product of Brazil, with a total production of more than 500 million tons. Knowledge of the bacterial community associated with agricultural crops and the soil status is a decisive step towards understanding how microorganisms influence crop productivity. However, most studies aim to isolate endophytic or rhizosphere bacteria associated with the plant by culture-dependent approaches. Culture-independent approaches allow a more comprehensive view of entire bacterial communities in the environment. In the present study, we have used this approach to assess the bacterial community in the rhizosphere soil of sugarcane at different times and under different nitrogen fertilization conditions. At the high taxonomic level, few differences between samples were observed, with the phylum Proteobacteria (29.6%) predominating, followed by Acidobacteria (23.4%), Bacteroidetes (12.1%), Firmicutes (10.2%), and Actinobacteria (5.6%). The exception was the Verrucomicrobia phylum whose prevalence in N-fertilized soils was approximately 0.7% and increased to 5.2% in the non-fertilized soil, suggesting that this group may be an indicator of nitrogen availability in soils. However, at low taxonomic levels a higher diversity was found associated with plants receiving nitrogen fertilizer. Bacillus was the most predominant genus, accounting for 19.7% of all genera observed. Classically reported nitrogen-fixing and/or plant growth-promoting bacterial genera, such as Azospirillum, Rhizobium, Mesorhizobium, Bradyrhizobium, and Burkholderia were also found although at a lower prevalence.
Assuntos
Bactérias/genética , Biota , RNA Ribossômico 16S/genética , Rizosfera , Saccharum/microbiologia , Microbiologia do Solo , Bactérias/classificação , Brasil , DNA Bacteriano/genética , Fertilizantes , Nitrogênio , Filogenia , Raízes de Plantas/microbiologiaRESUMO
Facial aging is a biological phenomenon. Skin properties change with time, and gravity and facial expressions exert mechanical deformation. Knowledge of these alterations may suggest ways to reverse them by identifying the corresponding distortional forces. The aim of this study was to determine a pattern of change for parameters of the face during the aging process, based on the numerical fitting of measures from a sample of patients. The first aspect of this study was to define adequate facial parameters and means of measuring them. Subsequently, each parameter was defined individually, and these data were analyzed as a set. The sample for the research was restricted to a group of 40 white female patients with a history of limited exposure to the sun, with ages ranging from 25 to 65. The reason for choosing this sample was the availability of frontal pattern photographs at different ages. The parameters for each patient were measured at two different ages. A strong correlation was found between age and behavior of the parameters. This aging model can be verified qualitatively by comparing photographs of a patient with manipulated photographs simulating aging. The quantitative verification of the model was done through the comparison of the measured and the predicted parameters.
Assuntos
Envelhecimento/patologia , Simulação por Computador , Face/anatomia & histologia , Modelos Biológicos , Adulto , Idoso , Algoritmos , Cefalometria , Olho/anatomia & histologia , Pálpebras/anatomia & histologia , Expressão Facial , Feminino , Previsões , Testa/anatomia & histologia , Gravitação , Humanos , Lábio/anatomia & histologia , Pessoa de Meia-Idade , Nariz/anatomia & histologia , Fotografação , Envelhecimento da Pele/patologia , Estresse MecânicoRESUMO
To evaluate cardiac growth in fetuses of those diabetic mothers with good metabolic control, we examined M-mode echocardiographic measurements obtained from 24 fetuses of diabetic mothers (FODM) and compared these with measurements from 31 normal fetuses of similar gestational age. Fetuses were grouped into three gestational periods: 20 to 26 weeks, 27 to 33 weeks, and 34 to 40 weeks. The mothers were believed to have good metabolic control on the basis of mean daily glucose profiles and glycosylated hemoglobin A (HbA1C) values of approximately 110 mg/dl (610 mumol/L) and 7.5%, respectively, before fetal scanning, and estimated fetal weight similar to that of normal fetuses during all three gestational periods. Both FODM and normal fetuses had significant increases in M-mode measurements from period 1 to period 3, but in FODM, cardiac hypertrophy developed by late gestation (period 3). This involved the interventricular septum (6.1 +/- 0.7 vs 4.9 +/- 0.3 mm, p less than 0.05), right ventricular free wall (5.7 +/- 0.8 vs 3.2 +/- 0.3 mm, p less than 0.01), and left ventricular free wall (6.4 +/- 0.6 vs 3.3 +/- 0.4 mm p less than 0.01). The interventricular septum/right ventricular free wall ratio was similar, whereas the interventricular septum/left ventricular free wall ratio in FODM was smaller by period 3 (1.0 +/- 0.1 vs 1.6 +/- 0.1, p less than 0.05). The right ventricular diastolic dimension was similar, but the left ventricular diastolic dimension was significantly smaller in FODM during periods 2 and 3 (8.2 +/- 1.2 vs 12.2 +/- 0.7 mm, p less than 0.05). Strict metabolic control did not prevent FODM from having abnormal cardiac growth. We conclude that good metabolic control results in normal estimated fetal weight but that FODM remain at risk for mild global cardiac hypertrophy and altered diastolic dimensions.
Assuntos
Coração/embriologia , Gravidez em Diabéticas , Glicemia/metabolismo , Ecocardiografia , Feminino , Humanos , Gravidez , Gravidez em Diabéticas/sangueRESUMO
A series of cases has been observed in which elastolysis and cutis laxa followed a chronic annular erythematous eruption. The diseases characterized by elastolysis and loose skin (cutis laxa; anetoderma) are briefly described, and a scheme for their classification and nomenclature is proposed. We are indebted to Dr. J. J. Jacobson and his colleagues, at the University of cape Town, for acess to their patients, and to Professors R. W. Goltz and Degos for illustrations...