RESUMO
The efficacy of an implant is highly depends on its coating characteristics mainly determined by polymer properties and coating technique. Electro-spraying is an inexpensive and versatile coating technique with various advantages for biomedical application. In this study, the efficacy of electro-sprayed (ES) poly lactic acid (PLA)-dexamethasone (DEX) coatings for medical implants was evaluated and compared with spin-coated samples as control. Structural properties of coatings were investigated using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Confocal and scanning electron microscopy (SEM), contact angle measurement and nanoindentation tests were used to study surface properties. Coating degradation rate and drug release profile were studied for 40 days. Cell viability experiments were also performed on human endothelial (HUVEC) and smooth muscle cells (HUASMC) using MTT assay and SEM. XRD and DSC analysis showed electro-spraying significantly reduce PLA and DEX crystallinity. Surface studies showed ES coatings has significantly higher hydrophobicity and roughness with microbead-nanofiber morphology vs. micro-nanoporous structure of spin-coated samples. Initial burst release of DEX was 22% and 10% after 6 h and total release was 71% and 46% after 40 days for ES and spin-coated samples, respectively. HUVEC viability of ES samples was higher than spin-coated ones after 1 and 4 days. However, dexamethasone release profile reduced HUASMC proliferation in ES PLA-DEX samples in comparison to spin-coated after 1 and 3 days. In conclusion, in vitro results showed potential of ES PLA-DEX as a biocompatible and efficient anti-inflammatory coating with suitable drug release profile for future applications such as coronary drug eluting stents.
RESUMO
OBJECTIVE: The aim of this study was to investigate the expression pattern of oncogenes, antimicrobial peptides, and genes involved in inflammation in leukoplakia of the oral cavity compared with healthy gingiva. STUDY DESIGN: Biopsies of healthy gingiva (n=20) and leukoplakia (n=20), were obtained during routine surgical procedures. RNA was extracted according to standard protocols. Transcript levels of alpha-defensin (DEFA) 1/3, DEFA-4, S100-A7, deleted-in-oral-cancer (Doc) 1, interleukin (IL) 1beta, IL-6, IL-8, IL-10, tumor necrosis factor (TNF) alpha, cyclooxygenase (Cox) 2, epidermal growth factor (EGF), keratinocyte growth factor (KGF), transforming growth factor (TGF) beta1, TGF-alpha, collagen-IA1 (Col-1), and tenascin-c were analyzed by real-time reverse-transcription polymerase chain reaction. The proteins encoded by the different genes were visualized by immunostaining. RESULTS: Compared with healthy gingiva (set as 1), there was an increased gene expression of DEFA-4 (179.2-fold), S100-A7 (25.4-fold), EGF (24.8-fold), TGF-beta1 (25.2-fold), and tenascin-c (34.3-fold) in oral leukoplakia. The expression of IL-1beta and Doc-1 was decreased (0.01-fold and 0.2-fold, respectively). CONCLUSIONS: The combination of an increased expression of the antimicrobial peptide DEFA-4, the oncogene S100-A7, EGF, and tenascin-c, and a decreased Doc-1 expression in oral leukoplakia might characterize its potency of malignant transformation. Chronic inflammation seems not to be involved in the development of this lesion.
Assuntos
Transformação Celular Neoplásica/metabolismo , Perfilação da Expressão Gênica , Gengiva/metabolismo , Leucoplasia Oral/metabolismo , Estudos de Casos e Controles , Diferenciação Celular/fisiologia , Transformação Celular Neoplásica/genética , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Cadeia alfa 1 do Colágeno Tipo I , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Fator de Crescimento Epidérmico/genética , Fator de Crescimento Epidérmico/metabolismo , Fator 7 de Crescimento de Fibroblastos/genética , Fator 7 de Crescimento de Fibroblastos/metabolismo , Gengiva/imunologia , Humanos , Imuno-Histoquímica , Interleucinas/genética , Interleucinas/metabolismo , Leucoplasia Oral/imunologia , RNA/análise , Valores de Referência , Proteína A7 Ligante de Cálcio S100 , Proteínas S100/genética , Proteínas S100/metabolismo , Tenascina/genética , Tenascina/metabolismo , Fator de Crescimento Transformador alfa/genética , Fator de Crescimento Transformador alfa/metabolismo , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , alfa-Defensinas/genética , alfa-Defensinas/metabolismoRESUMO
A sensitive and accurate differential-pulse polarographic method is reported for the measurement of lactate dehydrogenase (LDH) activity. The method is based on the polarographic measurement of the NAD+ formed via the enzymic reaction of LDH with pyruvate and NADH. The method was successfully applied to measure LDH activity in the serum of normal and diseased individuals.