Схемотехническое моделирование и синтез активных СВЧ-фильтров на полевых транзисторах Шоттки

Разработаны схемы активных СВЧ-фильтров, пригодных для исполнения в виде гибридной или полупроводниковой микросхемы

Уровень провоспалительных цитокинов внутриматочных смывов при гиперплазиях эндометрия

Проведено вивчення змін рівня прозапальних цитокінів ІЛ -1ß, ІЛ -6 та ФНП-α в маткових змивах у жінок з різними видами гіперплазій ендометрію. Встановлено, що формування гіперплазії ендометрію супроводжується активацією прозапальних цитокінів. Найбільш виражені зміни виявлені при комплексній гіперплазії ендометрію. Запальний процес в урогенітальної системі сприяє більш вираженому зростанню рівня цитокінів в маткових змивах. Оцінка вираженості змін в рівні цитокінів маткових змивів може використовуватися в якості додаткового критерію, що характеризує гіперплазії ендометрію, для оцінки формування запальних змін в ендометрії при його гіперплазії і для оцінки прогнозу перебігу гіперплазій.Levels of proinflammatory cytokines IL-1ß, IL-6 and TNF-α in uterine lavage fluid of women with different types of endometrial hyperplasia were studied. It is established that the formation of endometrial hyperplasia is associated with activation of proinflammatory cytokines. The most intensive changes were found in complex endometrial hyperplasia. Inflammation in the urogenital system leads to more intensive increase of cytokines level in the uterine washout. Investigation of changes in cytokines levels in uterine lavage fluid can be used as an additional criterion for characteristics of endometrial hyperplasia, to assess the formation of inflammatory changes in the endometrium and for prognosis of hyperplasia

Modulation of the immune response in strategies for bone regeneration

Transplantation of autologous (patient's own) bone is the gold standard in the repair of large bone defects. However, the limited amount of transplantable bone and the increased surgery time are major drawbacks of this technique. Several biological and synthetic off-the-shelf bone substitutes are available, but are still considered inferior to autologous bone. As the role of biomaterials for orthopedic applications is evolving from a structural role to a bioactive role to actively promote regeneration, the properties of these biomaterials are fine-tuned to direct the optimal tissue response. Study of the normal bone healing mechanisms shows that local factors expressed during the acute inflammatory response contribute to different processes needed for new bone formation. This generates the hypothesis that the modulation of the early inflammatory environment could be beneficial for the outcome. The aim of this thesis was to identify and test the feasibility of immune-modulatory strate­gies to enhance new bone formation. The results show that the incorporation of pro-inflammatory cytokines such as TNF-α or IL-17 into bone scaffolds can enhance bone formation in rabbits. Similarly, bacteria or specific components they hold, can induce immune responses that favor bone formation in rabbits. As an explanation for their bone-stimulating action, we show that pro-inflammatory mediators interact with bone-related growth factors to stimulate the formation of mature bone cells from progenitor cells. In summary, animal models were used to demonstrate that the local and short-lived delivery of pro-inflammatory cytokines is a potentially safe strategy to improve the efficacy of bone substitutes. Furthermore, selective bacterial ligands could have therapeutic merit in strategies for bone regeneration when the systemic effects can be controlled. To further explore the clinical relevance, the pro-in­flammatory stimuli with osteo-stimulatory potential should next be confirmed in larger, functional animal models

Evaluation of Vancomycin Prediction Methods Based on Estimated Creatinine Clearance or Trough Levels

Background:The aim of this study was to investigate whether vancomycin clearance (CLva) can be adequately predicted with CLva prediction methods. Additionally, other covariates influencing the CLva were investigated and predictivity of monitoring of only trough levels to 24-hour area under the curve (AUC(24)) was evaluated.Methods:Routine vancomycin plasma levels were measured with a fluorescence polarization immunoassay. Pharmacokinetic (PK) parameters of individual patients, that is, CLva and volume of distribution, were determined with maximum a posteriori Bayesian estimation. CLva was calculated with the 3 prediction methods, which are solely based on creatinine clearance (CLcr) estimated with Cockcroft and Gault formula and was compared with the calculated CLva with maximum a posteriori Bayesian estimation. Prediction errors were calculated. Correlations between CLva and CLcr, creatinine, age, weight, sex, and neutropenia were made. Furthermore, correlations between trough levels and AUC(24) were evaluated.Results:A total of 171 patients were included. Prediction errors and absolute prediction errors of the 3 methods ranged from 28% to 80% and 39% to 83%, respectively. In the multivariate analysis, CLva was significantly associated with CLcr, creatinine, age, weight, sex, and neutropenia. Linear correlation between AUC(24) and trough levels was R-2 0.38.Conclusions:Large prediction errors make the CLva algorithms based on estimated plasma CLcr unsuitable for use in patient care. Additionally, other factors, which are not accounted for in the current algorithms, influence the CLva individually. Owing to low association of AUC(24) and trough levels, the AUC(24) cannot be predicted with through levels. For a reliable AUC(24) guided vancomycin dosing, therapeutic drug monitoring is necessary

Neutrophils Inhibit Synthesis of Mineralized Extracellular Matrix by Human Bone Marrow-Derived Stromal Cells In Vitro

Although controlled local inflammation is essential for adequate bone regeneration, several studies have shown that hyper-inflammatory conditions after major trauma are associated with impaired fracture healing. These hyper-inflammatory conditions include the trauma-induced systemic inflammatory response to major injury, open fractures, and significant injury to the surrounding soft tissues. The current literature suggests that increased or prolonged influx of neutrophils into the fracture hematoma may mediate impairment of bone regeneration after hyper-inflammatory conditions. The underlying mechanism remains unclear. We hypothesize that high neutrophil numbers inhibit synthesis of mineralized extracellular matrix (ECM) by bone marrow stromal cells (BMSCs). We therefore studied the effect of increasing concentrations of neutrophils on ECM synthesis by human BMSCs in vitro. Moreover, we determined how high neutrophil concentrations affect BMSC cell counts, as well as BMSC osteogenic activity determined by alkaline phosphatase (ALP) expression and ALP activity. Co-culture of BMSCs with neutrophils induced a 52% decrease in BMSC cell count (p < 0.01), a 64% decrease in the percentage of ALP+ cells (p < 0.001), a 28% decrease in total ALP activity (p < 0.01), and a significant decrease in the amount of mineralized ECM [38% decrease after 4 weeks (p < 0.05)]. Co-cultures with peripheral blood mononuclear cells and neutrophils within transwells did not induce a significant decrease in ALP activity. In conclusion, our data shows that a decreased amount of mineralized ECM became synthesized by BMSCs, when they were co-cultured with high neutrophil concentrations. Moreover, high neutrophil concentrations induced a decrease in BMSC cell counts and decreased ALP activity. Clarifying the underlying mechanism may contribute to development of therapies that augment bone regeneration or prevent impaired fracture healing after hyper-inflammatory conditions

Osteoinduction by Ex Vivo Nonviral Bone Morphogenetic Protein Gene Delivery Is Independent of Cell Type

Ex vivo nonviral gene delivery of bone inductive factors has the potential to heal bone defects. Due to their inherent role in new bone formation, multipotent stromal cells (MSCs) have been studied as the primary target cell for gene delivery in a preclinical setting. The relative contribution of autocrine and paracrine mechanisms, and the need of osteogenic cells, remains unclear. This study investigates the contribution of MSCs as producer of transgenic bone morphogenetic proteins (BMPs) and to what extent the seeded MSCs participate in actual osteogenesis. Rat-derived MSCs or fibroblasts (FBs) were cotransfected with pBMP-2 and pBMP-6 or pBMP-7 via nucleofection. The bioactivity of BMP products was shown through in vitro osteogenic differentiation assays. To investigate their role in new bone formation, transfected cells were seeded on ceramic scaffolds and implanted subcutaneously in rats. Bone formation was assessed by histomorphometry after 8 weeks. As a proof of principle, we also investigated the suitability of bone marrow-derived mononuclear cells and the stromal vascular fraction isolated from adipose tissue for a one-stage gene delivery strategy. Bone formation was induced in all conditions containing cells overexpressing BMP heterodimers. Constructs seeded with FBs transfected with BMP-2/6 and MSCs transfected with BMP-2/6 showed comparable bone volumes, both significantly higher than controls. Single-stage gene delivery proved possible and resulted in some bone formation. We conclude that bone formation as a result of ex vivo BMP gene delivery can be achieved even without direct osteogenic potential of the transfected cell type, suggesting that transfected cells mainly function as a production facility for osteoinductive proteins. In addition, single-stage transfection and reimplantation of cells appeared feasible, thus facilitating future clinical translation of the method

Osteoinduction by Ex Vivo Nonviral Bone Morphogenetic Protein Gene Delivery Is Independent of Cell Type

Ex vivo nonviral gene delivery of bone inductive factors has the potential to heal bone defects. Due to their inherent role in new bone formation, multipotent stromal cells (MSCs) have been studied as the primary target cell for gene delivery in a preclinical setting. The relative contribution of autocrine and paracrine mechanisms, and the need of osteogenic cells, remains unclear. This study investigates the contribution of MSCs as producer of transgenic bone morphogenetic proteins (BMPs) and to what extent the seeded MSCs participate in actual osteogenesis. Rat-derived MSCs or fibroblasts (FBs) were cotransfected with pBMP-2 and pBMP-6 or pBMP-7 via nucleofection. The bioactivity of BMP products was shown through in vitro osteogenic differentiation assays. To investigate their role in new bone formation, transfected cells were seeded on ceramic scaffolds and implanted subcutaneously in rats. Bone formation was assessed by histomorphometry after 8 weeks. As a proof of principle, we also investigated the suitability of bone marrow-derived mononuclear cells and the stromal vascular fraction isolated from adipose tissue for a one-stage gene delivery strategy. Bone formation was induced in all conditions containing cells overexpressing BMP heterodimers. Constructs seeded with FBs transfected with BMP-2/6 and MSCs transfected with BMP-2/6 showed comparable bone volumes, both significantly higher than controls. Single-stage gene delivery proved possible and resulted in some bone formation. We conclude that bone formation as a result of ex vivo BMP gene delivery can be achieved even without direct osteogenic potential of the transfected cell type, suggesting that transfected cells mainly function as a production facility for osteoinductive proteins. In addition, single-stage transfection and reimplantation of cells appeared feasible, thus facilitating future clinical translation of the method

BMP-2 gene delivery in cell-loaded and cell-free constructs for bone regeneration

To induce osteogenicity in bone graft substitutes, plasmid-based expression of BMP-2 (pBMP-2) has been successfully applied in gene activated matrices based on alginate polymer constructs. Here, we investigated whether cell seeding is necessary for non-viral BMP-2 gene expression in vivo. Furthermore, to gain insight in the role of BMP-producing cells, we compared inclusion of bone progenitor cells with non-osteogenic target cells in gene delivery constructs. Plasmid DNA encoding GFP (pGFP) was used to trace transfection of host tissue cells and seeded cells in a rat model. Transgene expression was followed in both cell-free alginate-ceramic constructs as well as constructs seeded with syngeneic fibroblasts or multipotent mesenchymal stromal cells (MSCs). Titration of pGFP revealed that the highest pGFP dose resulted in frequent presence of positive host cells in the constructs. Both cell-loaded groups were associated with transgene expression, most effectively in the MSC-loaded constructs. Subsequently, we investigated effectiveness of cell-free and cell-loaded alginate-ceramic constructs with pBMP-2 to induce bone formation. Local BMP-2 production was found in all groups containing BMP-2 plasmid DNA, and was most pronounced in the groups with MSCs transfected with high concentration pBMP-2. Bone formation was only apparent in the recombinant protein BMP-2 group. In conclusion, we show that non-viral gene delivery of BMP-2 is a potentially effective way to induce transgene expression in vivo, both in cell-seeded as well as cell-free conditions. However, alginate-based gene delivery of BMP-2 to host cells or seeded cells did not result in protein levels adequate for bone formation in this setting, calling for more reliable scaffold compatible transfection methods

BMP-2 gene delivery in cell-loaded and cell-free constructs for bone regeneration

To induce osteogenicity in bone graft substitutes, plasmid-based expression of BMP-2 (pBMP-2) has been successfully applied in gene activated matrices based on alginate polymer constructs. Here, we investigated whether cell seeding is necessary for non-viral BMP-2 gene expression in vivo. Furthermore, to gain insight in the role of BMP-producing cells, we compared inclusion of bone progenitor cells with non-osteogenic target cells in gene delivery constructs. Plasmid DNA encoding GFP (pGFP) was used to trace transfection of host tissue cells and seeded cells in a rat model. Transgene expression was followed in both cell-free alginate-ceramic constructs as well as constructs seeded with syngeneic fibroblasts or multipotent mesenchymal stromal cells (MSCs). Titration of pGFP revealed that the highest pGFP dose resulted in frequent presence of positive host cells in the constructs. Both cell-loaded groups were associated with transgene expression, most effectively in the MSC-loaded constructs. Subsequently, we investigated effectiveness of cell-free and cell-loaded alginate-ceramic constructs with pBMP-2 to induce bone formation. Local BMP-2 production was found in all groups containing BMP-2 plasmid DNA, and was most pronounced in the groups with MSCs transfected with high concentration pBMP-2. Bone formation was only apparent in the recombinant protein BMP-2 group. In conclusion, we show that non-viral gene delivery of BMP-2 is a potentially effective way to induce transgene expression in vivo, both in cell-seeded as well as cell-free conditions. However, alginate-based gene delivery of BMP-2 to host cells or seeded cells did not result in protein levels adequate for bone formation in this setting, calling for more reliable scaffold compatible transfection methods