Photoaging and the clinical utility of fractional laser

Juliano Borges,1,2 Mônica Manela-Azulay,1,2 Tullia Cuzzi1,2 1Instituto de Dermatologia Professor Rubem David Azulay, Santa Casa de Misericórdia do Rio de Janeiro, 2Serviço de Anatomia Patológica da Faculdade de Medicina da Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil Abstract: The description of atomic structure by Niels Bohr set the basis for the emergence of quantum physics. Based on these fundamentals, Einstein published in 1917 a paper on the amplification of energy by Stimulated Emission of Radiation as part of his quantum theories. In 1955, Townes and Gordon turned Einstein's theories into practice, creating a coherent and amplified microwave device using ammonia gas in an optical medium. But it was at the beginning of the 1980s, that Anderson and Parrish published an article about the selective photothermolysis model which revolutionized clinical practice. The use of laser in photoaging began with CO2 (10,600 nm). In 1989, it was first used for resurfacing of a face with prominent photoaging. Ablative lasers have therefore had great popularity in the 1980s and 1990s, but prolonged postoperative time and significant risk of side effects have lowered the acceptance by patients. In 2004, the description of the fractionated radiation for the treatment of photoaging, by Mainstein, represented a great event. The stimulation of collagen occurred through fractional laser beams, which would reach the selected area while saving islands of sound skin. These islands accelerated the process of cicatrization of the treated tissue and shortened the postprocedure time. Furthermore, the fractionated radiation presented a smaller range of side effects, increasing the safety of the procedure. As mentioned earlier, as fractional lasers incise on the skin, they leave islands of healthy skin that accelerate recovery, while generating necrosis columns. Such necrosis columns remove damaged extracellular matrix material, allowing resettlement of fibroblasts. Such resettled fibroblasts, under the influence of a new tensile strength, restart to produce structures for extracellular matrix, such as collagen, elastin, and proteoglycans, in a more physiological way. Fractional lasers are considered by many dermatologists as the best choice in laser therapy for the treatment of photoaging. Keywords: fractional laser, photoaging, collagen, elastin, hyaluronic aci

Physico-chemical characterization of 'Zarco HS' yellow bell pepper for different ripeness stages Caracterização físico-química de pimentão amarelo 'Zarco HS' em diferentes estádios de maturação

The bell pepper presents alterations in its composition and its properties with the process of senescence during ripening. These composition and textual factors are part of the quality of the fruit and therefore of the selection. This permits the correct knowledge of the factors necessary for post-harvest measures, so that they can be adequately applied. The aim of this study is to analyze the 'Zarco HS' yellow pepper at various levels of ripeness taking into account its physico-chemical properties (titratable acidity, pH, total soluble solids, water content, and ascorbic acid), in order to understand this behavior during the ripening process. Bell peppers were separated based on their yellow percentage, which varied from 0% to 100%, and for each percentage five fruits were chosen as replicates. They were compared to 0%, 25%, 50%, 75% and 100% levels of ripening, due to the difficulty of the methodology in identifying the smaller differences between coloring. The 'Zarco HS' yellow bell pepper presents greater levels of soluble solids and lower levels of malic acid as the percentage of external yellow coloring increases. The yellow bell peppers, especially when totally yellow, represent an important source of vitamin C.<br>O pimentão apresenta, durante seu amadurecimento, alterações com o processo de senescência. Estes fatores de composição e propriedades texturais fazem parte da qualidade de frutas e hortaliças e, portanto da seleção. Isto faz com que seja necessário o correto conhecimento destes fatores, para que, através de testes físico-químicos, as tecnologias de conservação após a colheita possam ser adequadamente aplicadas. Este trabalho teve por objetivo analisar o pimentão amarelo 'Zarco HS' com vários graus de maturação quanto às propriedades físico-químicas (acidez titulável, pH, sólidos solúveis totais, teor de umidade e ácido ascórbico), para conhecimento deste comportamento durante o processo de amadurecimento. Os pimentões foram separados pela porcentagem de amarelo, que variou de 0% a 100%, e para cada porcentagem foram escolhidos 5 frutos, sendo cada fruto uma repetição. Os frutos foram comparados por faixas de amadurecimento, 0%, 25%, 50%, 75% e 100% devido à dificuldade de metodologia para identificar diferenças menores entre as colorações. O pimentão amarelo 'Zarco HS' apresenta níveis maiores de sólidos solúveis e níveis menores de ácido málico conforme aumenta a porcentagem externa de coloração amarelo. Pimentões, principalmente os totalmente amarelos, representam importante fonte de vitamina C