CESAR ISAAC
Projetos de Pesquisa
Unidades Organizacionais
LIM/04 - Laboratório de Microcirurgia, Hospital das Clínicas, Faculdade de Medicina - Líder
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
- Evaluation of Radiosterilized Glyercerolated Amniotic Membranes as a Substrate for Cultured Human Epithelial Cells(2020) PAGGIARO, Andre O.; MATHOR, Monica B.; TEODORO, Walcy R.; ISAAC, Cesar; CAPELOZZI, Vera L.; GEMPERLI, RolfHuman amniotic membrane (HAM) is a biomaterial with biological properties beneficial to tissue repair, serving as a substrate for cell cultivation. Irradiation is used for tissue sterilization, but can damage the HAM structure. The objective of this paper was to construct a skin substitute, composed of human keratinocytes cultured on glycerolated HAMs, and to evaluate the influence radiation on subsequent cell culture growth. Four batches of HAMs were glycerolated, and half of them were radio-sterilzed with 25 kGy. Non-irradiated glycerolated HAM (ni-HAM) and irradiated glycerolated HAM (i-HAM) samples were then de-epithelized and analyzed using optical microscopy (Picrossirius staining), immunofluorescence and electron microscopy. Subsequently, keratinocytes were cultured on ni- and i-HAMs, and either immersed or positioned at the air-liquid interface. The basement membranes of the ni-HAM group remained intact following de-epithelialization, whereas the i-HAM group displayed no evidence or remnant presence of these membranes. Concerning the keratinocyte cultures, the ni-HAM substrate promoted the growth of multi-layered and differentiated epithelia. Keratinocytes cultured on i-HAM formed epithelium composed of three layers of stratification and discrete cell differentiation. The glycerolated HAM was compatible with cultured epithelia, demonstrating its potential as a skin substitute. Irradiation at 25 kGy caused structural damage to the amnion.
- Comparative study of Silver Sulfadiazine with other materials for healing and infection prevention in burns: A systematic review and meta-analysis(2019) NIMIA, Heloisa Helena; CARVALHO, Viviane Fernandes; ISAAC, Cesar; SOUZA, Francisley Avila; GEMPERLI, Rolf; PAGGIARO, Andre OliveiraThe aim of this systematic review with meta-analysis was to compare the effect of Silver Sulfadiazine (SSD) with other new dressings, with or without silver, on healing and infection prevention in burns. The electronic search was carried out in the electronic databases of Pubmed, ScienceDirect, Lilacs and BVS. The articles included were randomized clinical trials about burn treatment with SSD, which evaluated the healing and infection of burn wounds in humans. The exclusion criteria included articles, editorials and letters published in the form of abstracts, unpublished reports and case series, cross-sectional, observational experimental studies, and the use of sulfadiazine for other types of wounds. The search identified 873 references, and 24 studies were included in accordance with the eligibility criteria. The results showed a statistically favorable difference related to the time of healing for silver dressings (p< 0.0001; MD 3.83; 95% CI 2.03-5.62) and dressings without silver (p< 0.007; MD 2.9; 95% CI 0.81-5.00) in comparison with SSD. The rate of infection showed no difference in the group treated with SSD compared with the group treated with dressings containing silver (p> 0.05). The rate of infection was significantly higher in the SSD group compared with the group treated with dressings without silver (p< 0.005; MD 25.29% and MD 12.97%). Considering the clinical trials conducted up to the present time, the authors concluded that new dressings withand without silver show better results than SSD for wound healing, and burn streated with dressings without silver are less likely to become infected than burns with SSD. No differences between SSD and new silver materials were observed in relation to infection prevention.
- Human fetal wound healing: a review of molecular and cellular aspects(2016) YAGI, Leticia Hitomi; WATANUKI, Larissa Martins; ISAAC, Cesar; GEMPERLI, Rolf; NAKAMURA, Yeda Midori; LADEIRA, Pedro Ribeiro SoaresThe physiological answer to after birth skin lesions is scarring, which compromises the function and the aesthetics of the injured area. However, fetuses in early gestation (24 weeks or less) respond to this damage with skin regeneration. To explain this difference, several factors are considered, such as increased production of collagen III in fetal fibroblasts and increased presence of this collagen in the skins of these fetuses. Increased hyaluronic acid in fetal matrix correlates with greater capacity for migration of fibroblasts in scarless repair. The fact that myofibroblasts in the wound appear only after the fetal stage of pregnancy which forms scars can also be correlated. Additionally, there is an increase in the amount of adhesion molecules in repair without scarring, which would multiply cell adhesion and migration. Lower levels of bTGF1 in fetal wound are correlated with reduced amounts of collagen I and may be the result of higher relative expression of bTGF3, which downregulates bTGF1. Amniotic fluid itself might be a stimulating factor to human skin's fibroblasts proliferation through cytokines such as bFGF and PDGF. A hypoxic environment in the fetal wound, associated with increased presence of Dot cells in blood, is also observed, and both facts can be related to a difference in the repair of the skin. Distinct gene expression guides those different responses and may also help to elucidate fetal skin regeneration. When the mechanisms responsible for the absence of scars in wounded fetuses are enlightened, it will be a significant mark in the studies of wound cicatrization and its therapeutic applications shall be extremely valuable.
- COMPARISONS OF THE RESULTS OF PERIPHERAL NERVE DEFECT REPAIR WITH FIBRIN CONDUIT AND AUTOLOGOUS NERVE GRAFT: AN EXPERIMENTAL STUDY IN RATS(2016) LONGO, Marco Vinicius Losso; FARIA, Jose Carlos Marques De; ISAAC, Cesar; NEPOMUCENO, Andre Coelho; TEIXEIRA, Nuberto Hopfgartner; GEMPERLI, RolfIntroduction: The standard treatment for nerve defects is nerve autograft. There is no conduit available that provides the same regenerative capacity of nerve autograft. This study evaluated the histological and functional recovery of nerve defects treated with fibrin conduit in comparison to the nerve autograft, in a rat model. Method: A sciatic nerve injury model (10-mm defect) was performed in 20 Wistar rats, nerve defect was reconstructed using a fibrin conduit (n=10). A nerve autograft was used as control (n=10). The walking behavior was measured by footprint analysis at 4, 8, and 12 weeks and sciatic function index was determined. After 12 weeks, histological analysis was performed to evaluate the regenerated nerve and measured axonal density. The triceps surae muscle weight was also evaluated. Results: The fibrin conduit group showed less improvement in walking behavior compared to nerve autograft (-53 +/- 2 vs. -36 +/- 2; P<0.001 at 12 weeks). The fibrin conduit group presented axonal density of 40.0 axons/10.995 mu m2 and the nerve autograft group had 67.2 axons/10.995 mu m2 (P<0.001). The triceps surae muscle weight ratio of the fibrin conduit group was 41 +/- 3% versus 71 +/- 4% of the nerve autograft group (P<0.001). Conclusion: The fibrin conduit could be used for nerve reconstruction following peripheral nerve injury in the rat model. However, the functional recovery in the fibrin conduit repair group was worse than that in nerve autograft group and the nerve repair with the fibrin conduit has less myelinated fibers when compared to the repair with nerve autograft. (C) 2015 Wiley Periodicals, Inc.