Estimation of the use of fibrin and collagen membranes as carriers for platelet-derived growth factor-BB (PDGF-BB) in the presence of amoxicillin.

The effect of homogeneous fibrin (Fb), collagen (Coll) and composite fibrin-heparin (Fb-Hp), fibrin-collagen (Fb-Coll) membranes on in vitro release of platelet-derived growth factor (PDGF-BB) was evaluated in the presence or absence of amoxicillin using of the ELISA immunoassay test. Amoxicillin concentration was determined spectrophotometrically at 272 nm. The process of the PDGF-BB growth factor and amoxicillin release from the studied membranes was of a two-phase nature in the majority of the systems analysed. The PDGF-BB was released in the highest amount from the Coll membrane (M7) without the presence of amoxicillin – 546.2 ±7.47 pg, t0.5 = 0.88 h and 202.5 ± 6.83 pg, t0.5 = 26.65 h during the first phase and second phase, respectively. The lowest PDGF-BB release was observed from composite M4 (Fb-Hp) membrane – 5.88 ± 0.81 pg, t0.5 = 1.69 h; and 110.2 ± 6.48 pg, t0.5 = 855.6 h during first and second phase respectively. An optimal release of amoxicillin was observed in the case of the composite M6 (Fb-Coll) membrane – only in the second phase: 64.2 ± 7.8 mg, t0.5 = 83.5 h. The lowest and delayed amoxicillin release was achieved for M4 membrane (approx. 17.1 ± 1.12 mg, t0.5 = 46.5 h). The results of the PDGF-BB release and amoxicillin from membranes indicated a correlation between the level of release and composition of the film. Our results suggested that fibrin and collagen membranes may be beneficial to enhance periodontal bone regeneration.

Effects of Platelet Lysate Preparations on the Proliferation of HaCaT Cells

BACKGROUND: Standard protocols are lacking for the preparation of platelet lysates (PL) as an alternative to using fetal bovine serum as a cell culture supplement. This study aimed to establish optimum conditions for preparing PL for use in cell cultures. METHODS: Cell density in three pooled platelet concentrates (PC) were adjusted to 1x10(12)/L and 2x10(12)/L. PL was prepared from PC by 1 to 3 freeze-thaw (FT) cycles. HaCaT cells were cultured in media supplemented with 5% or 10% PL. Cell numbers were estimated using a Cell Counting Kit-8 (CCK-8; Dojindo Laboratories, Japan). Growth factors were quantified by using the Luminex 200 system (Luminex Corporation, USA). RESULTS: Cell proliferation rates in the presence of PLs were similar when prepared from PCs of both cell densities. The rates were higher in media containing 5% PL than 10% PL when prepared by two FT cycles. Concentrations of vascular endothelial growth factor (VEGF), platelet-derived growth factor-AB/BB (PDGF-AB/BB), PDGF-AA, and epidermal growth factor (EGF) were significantly higher in PL prepared from PC with a cell density of 2x10(12)/L than 1x10(12)/L PC. However, only VEGF and PDGF-AA concentrations in PLs were correlated with HaCaT cell counts. CONCLUSIONS: The 5% PL from PC with a cell density of 1x10(12)/L prepared by two FT cycles treatment was the most effective condition that supported steady HaCaT cell proliferation. Our finding may be useful for preparing PL-supplemented cell culture media.

Oseointegración: una cascade de eventos / Osseointegration: a cascade of events

Por medio de esta revisión bibliográfica se pretende mostrar lo que existe en la actualidad sobre la biocompatibilidad, las características del titanio y su uso para implantes dentales y los eventos celulares y moleculares que se desencadenan con la colocación de un implante intraóseo en los maxilares. Se discute la terminología de: biotolerante, bioinerte, bioactivo, biointegración, bioaceptabilidad. Se establecen las características que hacen del titanio el material de eleción para su uso en los implantes dentales y los factores que permiten que se logre con ellos la oseointegración. En cuanto a los fenómenos celulares, se destaca el papel del osteoblasto como el blanco perfecto que permite desencadenar el proceso biológico que lleva a la oseointegración. A la vez se discute a nivel molecular todo el proceso de fenomenologías que ocurre desde el momento de la colocación del implante para permitir por parte del organismo una cicatrización normal alrededor de un cuerpo extraño. Esta información nos lleva a pensar que el entendimiento y manejo de todos estos eventos celulares y moleculares serían de gran utilidad para mejorar el éxito de los implantes dentales y extender su uso a sitios anatómicos que presentan dificultad a la terapéutica actual