17 research outputs found
Can space-for-time-substitution surveys represent zooplankton biodiversity patterns and their relationship to environmental drivers?
Space-for-Time-Substitution surveys (SFTS) are commonly used to describe zooplankton community dynamics and to determine lake ecosystem health. SFTS surveys typically combine single point observations from many lakes to evaluate the response of zooplankton community structure and dynamics (e.g., species abundance and biomass, diversity, demographics and modeled rate processes) to spatial gradients in hypothesized environmental drivers (e.g., temperature, nutrients, predation), in lieu of tracking such responses over long time scales. However, the reliability and reproducibility of SFTS zooplankton surveys have not yet been comprehensively tested against empirically-based community dynamics from longterm monitoring efforts distributed worldwide. We use a recently compiled global data set of more than 100 lake zooplankton time series to test whether SFTS surveys can accurately capture zooplankton diversity, and the hypothesized relationship with temperature, using simulated SFTS surveys of the time series data. Specifically, we asked: (1) to what degree can SFTS surveys capture observed biodiversity dynamics; (2) how does timing and duration of sampling affect detected biodiversity patterns; (3) does biodiversity ubiquitously increase with temperature across lakes, or vary by climate zone or lake type; and (4) do results from SFTS surveys produce comparable biodiversity-temperature relationship(s) to empirical data within and among lakes? Testing biodiversity-ecosystem function (BEF) relationships, and the drivers of such relationships, requires a solid data basis. Our work provides a global perspective on the design and usefulness of (long-term) zooplankton monitoring programs and how much confidence we can place in the zooplankton biodiversity patterns observed from SFTS surveys
Evaluation of red blood cell osmotic resistance as an additional method for assessing the blood biocompatibility of biomaterials
Autotransplantation of cartilage-bone chips using a collagen barrier membrane - a pilot study of cartilage defects healing
Urazy chrz膮stki stawowej stanowi膮 trudny problem terapeutyczny. Poznanie budowy oraz fizjologii chrz膮stki pozwala zrozumie膰 jej funkcj臋 oraz patomechanizm odpowiedzialny za jej niszczenie w przebiegu uraz贸w, chor贸b zwyrodnieniowych oraz chor贸b autoimmunologicznych. Aktualnie badania nad gojeniem uszkodze艅 chrz膮stki stawowej koncentruj膮 si臋 na in偶ynierii tkankowe, modyfikacji metod chirurgicznych oraz wykorzystaniu biomateria艂贸w. Badania pilota偶owe przeprowadzone w Zak艂adzie Chirurgii Eksperymentalnej i Badania Biomateria艂贸w mia艂y na celu sprawdzenie mo偶liwo艣ci odbudowy uszkodzonej chrz膮stki stawowej z zastosowaniem autoprzeszczepu wi贸r chrz臋stno-kostnych i dwuwarstwowej b艂ony kolagenowej. Wst臋pne badania w 8 i 10 tygodniu nad autoprzeszczepem wi贸r chrz臋stno-kostnych wykazywa艂y przewag臋 proces贸w regeneracyjnych nad reparacyjnymi.Articular cartilage injuries are a difficult therapeutic problem. Acquiring the knowledge of the structure and physiology of cartilage is a key to understanding its function and the pathogenesis responsible for its destruction in the course of injury, degenerative diseases and autoimmune disorders. Currently, research on the articular cartilage healing focus on tissue engineering, modification of surgical methods and the use of biomaterials. Pilot studies conducted at the Department of Experimental Surgery and Biomaterials Research aimed to explore the possibilities of rebuilding the damaged cartilage using autograft cartilage-bone chips and double-layer collagen membrane. Preliminary studies in 8 and 10 week of observation showed superiority over reparative regenerative processes
Studies of reaction of gelatin-alginate matrixes on morphotic elements and blood proteins
W pracy przedstawiono ocen臋 dzia艂ania hemolitycznego i hemostatycznego matryc 偶elatynowo-alginianowych oraz matryc sieciowanych mleczanem wapnia po czasowym kontakcie z krwi膮 w badaniach in vitro. Na podstawie uzyskanych wynik贸w bada艅 stwierdzono, 偶e matryce nie wywo艂uj膮 istotnych zmian w warto艣ciach odsetka hemolizy i st臋偶enie hemoglobiny osoczowej. Powoduj膮 aktywacj臋 uk艂adu krzepni臋cia, skr贸cenie czasu rekalcynacji krwi i wyd艂u偶enie APTT. Warto艣ci pomiarowe mieszcz膮 si臋 w zakresie warto艣ci referencyjnych oznaczonych parametr贸w.The paper presents an evaluation of hemolytic and hemostatic activity of gelatin-alginate matrixes and cross-linking of the matrix with calcium ions after contact with human blood in vitro studies. In view of the results in has been reported that a matrix does not cause important quantitative changes in the percentage of hemolysis and free hemoglobin concentration. In the plasma coagulation system evaluation blood recalcyfication time was shortened and activated partial thromboplastin time (APTT) was prolonged. That suggested that coagulation processes were activated
The evaluation of physicochemical properties and cytotoxicity of the obtained calcium phosphate cements for filling bone defects in medical applications
Badania przeprowadzono pod k膮tem oceny w艂a艣ciwo艣ci fizykochemicznych, biozgodno艣ci i cytotoksyczno艣ci cement贸w wapniowofosforanowych do iniekcyjnego wype艂niania ubytk贸w ko艣ci w zastosowaniach medycznych. Wszystkie otrzymane cementy zosta艂y por贸wnane w niekt贸rych zakresach: czasu wi膮zania, wytrzyma艂o艣ci na 艣ciskanie, zarabialno艣ci, podatno艣ci na iniekcj臋 i integralno艣ci w 艣rodowisku symuluj膮cym p艂yn fizjologiczny (SBF). Oceniono cytotoksyczno艣膰 cement贸w w bezpo艣rednim kontakcie z niekt贸rymi fibroblastami mysimi 3T3 Balb/C, przy czym udowodniono, 偶e mo偶na poprawi膰 ich w艂a艣ciwo艣ci przez modyfikacj臋 sk艂ad贸w i otrzyma膰 iniekcyjne, biozgodne cementy odpowiednie do zastosowa艅 klinicznych.The aim of the research was to evaluate of physicochemical properties and biocompatibility of the obtained calcium phosphate cements, intended for filling bone defects in surgery by means of injection. All obtained cements were compared in terms of the setting time, compressive strength, handling properties, injectability and integrity in SBF. Analysis of cytotoxicity of cements in immediate contact with 3T3 Balb/C mouse fibroblasts has been performed. It was demonstrated that it can improve the properties of calcium phosphate cement by modification its compositions to obtain injectable, biocompatible cements suitable for the clinical use
Effect of pyrolytic carbon on the morphological parameters of blood
W pracy przedstawiono analiz臋 ilo艣ciow膮 wybranych parametr贸w morfologicznych krwi po jej czasowym kontakcie z materia艂em w臋glowym LTI. Na podstawie uzyskanych wynik贸w nie stwierdzono zmian w warto艣ciach parametr贸w uk艂adu czerwonokrwinkowego, natomiast zaobserwowano zmiany w warto艣ciach parametr贸w uk艂adu bia艂okrwinkowego i p艂ytkowego. Zaobserwowane zmiany w warto艣ciach parametr贸w morfologicznych nie przekraczaj膮 zakresu warto艣ci referencyjnych dla tych wska藕nik贸w.A quantitative analysis of selected morphological parameters of blood after its temporal contact with LTI carbon material was presented in the study. The obtained results indicate that the values of parameters of erythrocyte system did not change, while the values of parameters of leukocyte and platelet systems were altered. The changes in the values of parameters did not exceed the range of referential values for these indexes
Experimental studies of biological evaluation of calcium phosphate cement implants injected to bone tissue
Nieregularne ubytki ko艣ci, zw艂aszcza umiejscowione w g艂臋bi ko艣ci, s膮 trudne do uzupe艂nienia materia艂ami litymi bez usuni臋cia zdrowej tkanki ponad ubytkiem. Odpowiednim materia艂em mog艂aby by膰 resorbowalna ceramika w postaci p艂ynnej. W tym celu opracowano w Instytucie Szk艂a i Ceramiki (ISiC) trzy postacie cement贸w wapniowo-fosforanowych mog膮cych by膰 wszczepianymi iniekcyjnie. Komponenty proszkowe tych cement贸w zawiera艂y α-TCP i/lub β-TCP i/lub DCP i/lub DCPD i/lub i/lub HA i/lub alginian sodu. Proszki zarabiane roztworami wodnymi 12% wag. bursztynianu sodu lub 1-3% wag. Na2HPO4 mia艂y p贸艂p艂ynn膮 posta膰, mo偶liw膮 do implantacji metod膮 iniekcji za pomoc膮 strzykawki lekarskiej i ig艂y iniekcyjnej do wytworzonych ubytk贸w w ko艣ci udowej kr贸lik贸w. Okres obserwacji wynosi艂 1, 2 i 3 miesi膮ce. W badaniach histologicznych obserwowano w pierwszym miesi膮cu po wszczepieniu obecno艣膰 fazy wysi臋kowej w tkance bezpo艣rednio przylegaj膮cej do wszczepu, kt贸ra ust臋powa艂a w drugim miesi膮cu po wszczepieniu. Ulegaj膮ce biodegradacji cementy otoczone by艂y cienkimi pasmami w艂贸knistej tkanki 艂膮cznej oraz tkanki kostnej splotowatej, kt贸re wnika艂y w struktur臋 wszczepu. W 3 miesi膮cu cz臋艣ciowo zresorbowane i pofragmentowane wszczepy otacza艂a i przerasta艂a g艂贸wnie splotowata i blaszkowata tkanka kostna z wyspami tkanki 艂膮cznej. Najszybciej procesy resorbcji wszczepu i regeneracji ko艣ci przebiega艂y po wszczepieniu cementu zawieraj膮cego alginian sodu. Badania eksperymentalne wykaza艂y, 偶e wszystkie trzy rodzaje cement贸w wapniowo-fosforanowych s膮 biozgodne, wykazuj膮 cechy osteoindukcji i osteokondukcji. Ich p艂ynna forma umo偶liwia 艂atwe i szczelne wype艂nianie nieregularnych lub g艂臋boko w ko艣ci po艂o偶onych ubytk贸w.Irregular bone loss, especially situated deeply inside the bone, cannot be easily filled with solid materials without removal of healthy bone tissue from above the loss. Thus resorbable liquid ceramic material could be a good alternative. For this reason, three forms of injectable calcium phosphate cements have been developed at the Institute of Glass and Ceramics (ISiC). Powder components of the cements contained α-TCP and/or β-TCP and/or DCP and/or DCPD and/or HA and/or sodium alginate. The powders, mixed with aqueous solutions of 12 wt.% sodium succinate or 1-3 wt.% Na2HPO4, had a semi-liquid form that could be applied by means of injection with a medical syringe and an injection needle to the site of bone loss in the rabbits' femur. The follow up period was 1, 2 and 3 months, Histological examinations one month after the injection revealed the presence of exudates in the tissue adjoining the implant, which disappeared two months after the injection. Undergoing biodegradation cements were surrounded by a thin layer of fibrous tissue and plexiform bone tissue, which penetrated the structure of the implant. In the third month, partly resorbed and fragmented implants were surrounded and overgrown mainly with plexiform and lamellar bone tissue with islands of connective tissue. The processes of implant resorption and bone regeneration were the quickest in the case of cement containing sodium alginate. The experimental studies have shown that all three kinds of calcium phosphate cement are biocompatible and reveal features of osteoinduction and osteoconduction. The liquid form enables easy and tight filling of irregular or deep-seated bone loss