Genetic algorithm applied to simultaneous parameter estimation in bacterial growth.

Several mathematical models have been developed to understand the interactions of microorganisms in foods and predict their growth. The resulting model equations for the growth of interacting cells include several parameters that must be determined for the specific conditions to be modeled. In this study, these parameters were determined by using inverse engineering and a multi-objective optimization procedure that allows fitting more than one experimental growth curve simultaneously.

Mechanistically Inspired Kinetic Approach to Describe Interactions During Co-Culture Growth of Carnobacterium maltaromaticum and Listeria monocytogenes.

Lactic acid bacteria and Listeria monocytogenes are psychotropic organisms that can grow and compete in food such as lightly preserved fishery products. Predictive microbiology is nowadays one of the leading tools to assess the behavior of bacteria in food and to predict food spoilage. Mathematical models can be used to predict the growth, inactivation or growth probability of bacteria.

Bone grafts prepared with selective cell retention technology heal canine segmental defects as effectively as autograft.

Using a canine critical-size segmental defect model, a two-phased study was undertaken to evaluate the healing efficacy of demineralized bone and cancellous chips (DBM-CC) enriched with osteoprogenitor cells using a Selective Cell Retention (SCR) technology. The goals of this study were: 1) to determine the bone-healing efficacy of SCR-enriched grafts versus autograft, and 2) to assess the value of clotting SCR-enriched grafts with platelet-rich plasma (PRP). Thirty dogs were included in Phase I: 18 dogs were treated with an SCR-enriched DBM-CC graft clotted with autologous bone marrow, and were compared to 12 autograft controls.

Preformed grafts of porcine small intestine submucosa (SIS) for bridging segmental bone defects.

Previous studies suggest that fresh, morselized porcine small intestine submucosa (SIS) may have promise in the treatment of large bone defects. This study evaluated the bone regenerative potential of preformed tubular SIS grafts, designed to provide a scaffold for regeneration of diaphyseal bone. Critical length segmental defects in the femurs of male rats were either left unfilled (n = 11) or filled with morselized cancellous bone (n = 12), or spanned with intramedullary tubes (n = 12) or periosteal sleeves (n = 12) fabricated from SIS.

1alpha,25-(OH)2D3 regulates 25-hydroxyvitamin D3 24R-hydroxylase activity in growth zone costochondral growth plate chondrocytes via protein kinase C.

Rat costochondral chondrocytes possess 25-hydroxyvitamin D3 1alpha- and 24R-hydroxylase activities and metabolize 25-(OH)D3 to 1,25-(OH)2D3 and 24,25-(OH)2D3 in a cell maturation-specific and time-dependent manner. This study examined the hypothesis that 1alpha,25-(OH)2D3 and 24R,25-(OH)2D3 regulate the activities of both hydroxylases in prehypertrophic/upper hypertrophic (growth zone) chondrocytes, and 1alpha,25-(OH)2D3 exerts its effects via mechanisms involving protein kinase C (PKC) mediated pathways. Rat costochondral growth zone chondrocytes were treated with 10(-9) - 10(-7) M 1alpha,25-(OH)2D3 or 24R,25-(OH)2D, for 24 hours, and 1alpha- and 24R-hydroxylase activities in cell homogenates determined by measuring the conversion of [3H]-25-(OH)D3 to [3H]-1,25-(OH)2D3 and [3H]-24,25-(OH)2D3.