[Effects of different growth factors on new bone formation: a systematic review]

Using different osteogenic growth factors, which is still under investigation, is a favorable method for bone regeneration. This systematic review is aimed at evaluating the effects of different growth factors and their carriers on osteogenesis. Electronic databases [Medline, EMBase and Cochrane] were searched by the authors for articles published from 1999 to April 2010. Clinical and animal studies evaluating bone formation by applying a specific growth factor and the related carrier were included in this investigation. Obtained data were organized in a table and evaluated through a qualitative analysis. Sixty-three studies most of which evaluated the effects of BMP-2 osteogenesis in different models were included in this study. Totally, twenty-five carriers were applied with different growth factors in the experiments. Among these carriers, poly lactic- co glycolic acid [PLGA], hydroxy apatite/tricalcium phosphate/absorbable collagen sponge [HA/TCP/ACS] and BioOss were the most frequently used carriers with the growth factors in bone regeneration studies. The current evidence, although not strong enough, confirms that BMP-2 has more favorable results in osteogenesis compared with other factors. The carrier scaffold, methods of measurement [histologic or radiographic], type of animal, defect diameter and the length of follow-up are the variables that should be matched before reaching definite results for the effect of growth factors in bone regeneration

Producción de ácido láctico por una mezcla de Lactococcus lactis y Streptococcus salivarius en fermentaciones en discontinuo / Lactic acid production from a mixture of cultures of Lactococcus lactis and Streptococcus salivarius using batch fermentation

Se estudió la producción de ácido láctico (AL), la conversión de sustrato (CG), y el rendimiento (Y p/s) de Lactococcus lactis, Streptococcus salivarius y una mezcla 1:1 de ambas cepas en sustrato glucosado. Lactococcus lactis se seleccionó de 20 cepas homofermentativas aisladas de cultivos de caña de azúcar variedad CC85-92 y Streptococcus salivarius se aisló de un fermento láctico comercial. En fermentaciones llevadas a cabo con lamezcla microbiana, a 32 °C con 60 gL-1 de glucosa y pH 6,0 se obtuvo un máximo de 47,63 gL-1 de ácido láctico, conversión de glucosa de 95,4% y rendimiento en producto de 0,83 gg-1.

Production of lactic acid (LA), yield (Y p/s) and substrate conversion (SC) from Lactococcus lactis, Streptococcus salivarius and their mixtures were tested. Lactococcus lactis was selected from 20 homofermentative strains isolated from a sugar cane crop (variety CC85-92) and Streptococcus salivarius was isolated from a commercial lactic ferment. Batch fermentation experiments at 32 C with a glucose concentration of 60 gL-1 and a pH of 6,0 were carried out. A maximum of 47,63 gL-1 of lactic acid concentration, 95,4% of substrate conversion and 83 gg-1were obtained from the mixture of strains after a fermentation of 48 h.