Immobilization of cells by electrostatic droplet generation: a model system for potential application in medicine

The process of electrostatic extrusion as a method for cell immobilization was investigated that could be used for potential applications in medicine. An attempt was made to assess the effects of cell addition and polymer concentration on the overall entrapment procedure, ie, on each stage of immobilization: polymer-cell suspension rheological characteristics, electrostatic extrusion process, and the process of gelation. The findings should contribute to a better understanding of polymer–cell interactions, which could be crucial in possible medical treatments. Alginate–yeast was used as a model system for carrier-cells. The electrostatic extrusion was considered as a complex two-phase flow system and the effects of cell and alginate concentrations on the resulting microbead size and uniformity were assessed. Under investigated conditions, microbeads 50–600 μm in diameter were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with higher standard deviations in size. We attempted to rationalize the findings by rheological characterization of the cell–alginate suspensions. Rheological characterization revealed non-Newtonian, pseudoplastic behavior of cell-alginate suspensions with higher viscosities at higher alginate concentrations. However, the presence of cells even at high concentrations (5×108 and 1×109 cells/mL) did not significantly affect the rheological properties of Na-alginate solution. Lastly, we investigated the kinetics of alginate gelation with respect to the quantity of Ca2+ ions and cell presence. The gelation kinetics were examined under conditions of limited supply with Ca2+ ions, which can be essential for immobilization of highly sensitive mammalian cells that require minimal exposure to CaCl2 solution. The molar ratio of G units to Ca2+ ions of 3.8:1 provided complete crosslinking, while the increase in alginate concentration resulted in prolonged gelation times but higher strength of the resulting gel. The cell presence decreased the rate of network formation as well as the strength of the obtained Ca-alginate hydrogel

Influence of Intensive Animal Breeding to the Appearance of Infectious Diseases (Zoonoses)

Intensive animal breeding and production is based on farm breeding of animals which represents a major source of raw material for food production. Preserving health of animals requires a good practice during breeding, appropriate feeding and watering, adequate control of pests and wild animals. Animal breeding and production of food of animal origin requires significant engagement of veterinary services within the frame of epizootiological, epidemiological, veterinary and sanitary surveillance. Farm manner of cattle breeding can represent a danger of air, water and ground contamination. In the farms situated in a small space, overcrowded with animals there are ideal conditions for the appearance and spreading of causative agent of infectious diseases (prions, viruses, rickettsiae, chlamydia, bacteria, parasites and fungi), which can be transmitted also to humans and wild animals. From the aspect of public health, special attention should be given to the farms with large number of animals and farms with intensive breeding conditions. This is especially important in pig and poultry breeding, where moderate or high prevalence of infections such as salmonellosis and campylobacteriosis are often present, regardless of the fact that the level of clinical illness caused by these infections is relatively low. Intensive production in animal husbandry leads to increased animal waste, and the richest source of infectious agents represents animal feces

Optimizacija procesa izolovanja hemoglobina iz goveđih eritrocita kontrolisanom hemolizom

In this work, we describe an optimized procedure based on gradual hemolysis for the isolation of hemoglobin derived from bovine slaughterhouse erythrocytes in a membrane bioreactor. The membrane bioreactor system provided high yields of hemoglobin (mainly oxyhemoglobin derivate) and its separation from the empty erythrocyte membranes (ghosts). Ten different concentrations of hypotonic media were assessed from the aspect of the extent of hemolysis, hematocrit values of the erythrocyte suspensions, cell swelling and membrane deformations induced by decreased salt concentration. Effective gradual osmotic hemolysis with an extent of hemolysis of 83% was performed using 35 mM Na-phosphate/NaCl buffer of pH 7.2-7.4. Under these conditions most of the cell membranes presented the appearance of the normal ghosts under phase contrast microscope. The results show that isolation process yielded predominantly to oxyhemoglobin. Kinetic studies showed that maximal concentration of hemoglobin was reached after 40 min, but the process cycle at which recovery of 83% was achieved lasted for 90 min.Dugi niz godina, i kod nas i u svetu, razvijaju se tehnološki postupci za izolovanje strukturno očuvanog i biološki aktivnog hemoglobina koji bi mogao da se koristi kao zamenik za krv, kao izvor biološki visokoaktivnog hemskog gvožđa u prevenciji anemije kod ljudi i životinja, ili kao reagens u dijagnostici. U ovom radu optimizovan je postupak za izolovanje hemoglobina iz eritrocita poreklom iz otpadne klanične goveđe krvi sa ciljem dobijanja preparata hemskog gvožđa za prevenciju anemije kod životinja. Testirana je osetljivost goveđih eritrocita na osmotsku lizu sa ciljem definisanja optimalnog puferskog sistema za efikasno izvođenje kontrolisane hemolize. Dobijeni rezultati su pokazali da goveđi eritrociti imaju povećanu osmotsku osetljivost u odnosu na humane eritrocite, a da je optimalan puferski sistem za izvođenje njihove kontrolisane hemolize 35 mM natrijum-fosfatni/NaCl pufer pH 7,2-7,4. Kontrolisana hemoliza sa optimizovanim puferskim sistemom je izvedena u membranskom reaktorskom sistemu i ostvaren je prinos hemoglobina od 83±12%. Tokom ovog procesa nije došlo do oštećenja membrane eritrocita, a intaktne membrane praznih eritrocita bi se mogle koristiti za inkapsulaciju biološki aktivnih supstanci

Efekti IL-17 na funkcionalnu aktivnost ćelija periferne krvi

Interleukin-17 (IL-17) is a proinflammatory cytokine produced mainly by activated CD4+ and CD8+ T cells, while its specific receptor is ubiquitously distributed. The inflammatory capacity of IL-17 is based on its ability to stimulate a wide range of stromal cells to produce and release a number of proinflammatory mediators, some with a known impact on hematopoiesis particularly granulopoiesis. Recent data indicate a role for IL-17 in the pathogenesis of several inflammatory diseases, transplant rejection and tumor growth. The purpose of this study was to determine functional responses including the respiratory burst, nitric oxide (NO) production, adhesiveness and metabolical activity/viability of human peripheral blood leukocytes (total white blood cells, mononuclear cells and granulocytes) from healthy donors in the presence of recombinant human (rh)IL-17. The obtained results showed that rhIL-17 did not induce significant changes in the respiratory burst, NO production, and metabolical activity of each peripheral blood cell fraction the tested, while a slight increase in phorbol-12-myristate-13-acetate (PMA) stimulated adhesiveness of granulocytes and mononuclear cells was noted. The absence of significant changes in tested functional activities of various peripheral blood cells suggests that IL-17 does not express its proinflammatory ability in steady-state, since the requirement for its action really does not exist.Interleukin 17 (IL-17) je proinflamatorni citokin koga produkuju aktivirane CD4+ i CD8+ T ćelije, dok je njegov receptor ubikvitarno distribuiran. Inflamatorni kapacitet IL-17 se zasniva na njegovoj sposobnosti da stimuliše širok spektar stromalnih ćelija da produkuju i oslobađaju različite proinflamatorne medijatore, među kojima neki imaju efekte na hematopoezu posebno granulopoezu. Dosadašnji podaci ukazuju na ulogu IL-17 u patogenezi različitih inflamatornih bolesti, odbacivanju transplanta i razvoju tumora. Cilj ovog rada je bio da se odrede funkcionalni odgovori, uključujući respiratorni prasak, produkciju azot monoksida (NO), adhezivnost i metaboličku aktivnost/vijabilnost različitih ćelija periferne krvi (ukupnih leukocita, mononuklearnih ćelija i granulocita) zdravih donora, u prisustvu IL-17. Dobijeni rezultati su ukazali da IL-17 ne dovodi do značajnih promena respiratornog praska, produkcije NO i metaboličke aktivnosti ćelija periferne krvi, ali da uzrokuje blago povećanje forbol-12-miristat-13-acetat (PMA) stimulisane adhezivnosti granulocita i mononuklearnih ćelija. Odsustvo značajnih promena u ispitivanim funkcionalnim aktivnostima različitih ćelija periferne krvi, ukazuje da IL-17 ne eksprimira proinflamatorno dejstvo kod zdravih osoba, jer najverovatnije i ne postoji potreba za njegovim delovanjem

Inkapsulacija resveratrola u sferične čestice na bazi hidrogelova dozvoljenih za upotrebu u hrani

The paper reports about the preparation and characterization of hydrogel particles containing liposomes loaded with resveratrol as an active compound. The materials used for preparation of the particles were chosen to be suitable for food industry. Different polymer concentrations affect particles shape, size, size distribution, as well as the release kinetics of resveratrol. The diameter of particles varied from 360 to 754 μm, while the narrow size distribution was observed for all types of particles. Release studies were performed in Franz diffusion cell and the results showed the prolonged release of resveratrol from all samples, but the sample with the highest content of polymer (2.5% w/w) in particular stood out. The research provides useful information about liposomes containing active compound encapsulated in hydrogel matrices and offers the basis for its application in the food industry.Ovaj rad daje podatke o pripremi i karakterizaciji čestica koje sadrže lipozome sa inkapsuliranom aktivnom komponentom resveratrolom. Komponente koje ulaze u sastav ovih čestica odabrane su tako da mogu jednostavno da se primene u prehrambenoj industriji. Prikazan je uticaj različitih koncentracija početnih rastvora polimera čija upotreba je dozvoljena u hrani, a samim tim i njihove viskoznosti na veličinu formiranih čestica, njihov oblik i raspodelu veličina, ali i na otpuštanje resveratrola iz ovih složenih sistema. Prečnik čestica bio je između 360 i 754 μm, dok je uska raspodela veličina detektovana u svim uzorcima. Otpuštanje resveratrola praćeno je u Francovoj difuzionoj ćeliji gde su rezultati ukazali na produženo oslobađanje resveratrola u svim uzorcima. Ipak, uzorak koji je imao najveći udeo polimera u početnom rastvoru (2,5% w/w) najsporije je otpuštao aktivnu komponentu. Ovi rezultati daju korisne podatke o kompleksnim sistemima gde je aktivna komponenta inkapsulirana u lipozome dalje obložena polimerom čime doprinose potencijalnoj aplikaciji ovih i sličnih sistema u prehrambene proizvode

Primena neravnotežne plazme u medicini

The potential of plasma applications medicine, the connections to nanotechnologies and the results obtained by our group are reviewed. A special issue in plasma medicine is the development of the plasma sources that would achieve non-equilibrium at atmospheric pressure in an atmospheric gas mixture with no or only marginal heating of the gas, and with desired properties and mechanisms that may be controlled. Our studies have shown that control of radicals or chemically active products of the discharge, such as ROS (reactive oxygen species) and/or NO, may be used to control the growth of the seeds. Simultaneously, a specially designed plasma needle and other sources were shown to be efficient to sterilize not only colonies of bacteria but also plank- tonic samples (microorganisms protected by water) or bio films. Finally, it was shown that a plasma might induce differentiation of stem cells. Non-equilibrium plasmas may be used in detection of different specific markers in medicine. For example proton transfer mass spectroscopy may be employed in the detection of volatile organic compounds without their dissociation and thus as a technique for instantaneous measurement of the presence of markers for numerous diseases.U ovom radu dat je pregled primene plazme u medicini, povezanost sa nanotehnologijama i rezultate na ovom polju koje je postigla naša grupa. Poseban problem u plazma medicini je razvoj izvora plazme koji bi radili u neravnotežnim uslovima na atmosferskom pritisku i u smeši gasova kakva je u atmosferi uz zanemarljivo grejanje gasa i sa željenim karakteristikama koje se mogu podešavati po želji. Naša istraživanja su pokazala da se kontrola prisustva radikala i drugih hemijski aktivnih čestica kao što su reaktivne kiseonične čestice (ROS) i/ili NO, može koristiti za kontrolu klijanja semenki. U isto vreme je dokazano za posebno konstruisanu plazma iglu da može efikasno da steriliše ne samo kolonije bakterija već i planktonske uzorke (mikroorganizme zaštićene vodom) pa i biofilmove. Na kraju, mi smo pokazali da plazma može da indukuje diferencijaciju matičnih ćelija. Neravnotežna plazma se može koristiti za detekciju raznih specifičnih markera u medicini. Na primer masena spektroskopija na bazi izmene protona može da se koristi za detekciju isparivih organskih jedinjenja bez njihove disocijacije i na taj način se može ostvariti trenutna detekcija markera za brojne bolesti iz daha

Savremeni procesi inkapsulacije u tehnologiji hrane

The encapsulation processes have been intensively studied in the recent years as possible alternative to conventional food technologies. Encapsulation of food active compounds is based on formation of protective layer(s) around active compound using adequate encapsulation technique. The role of protective layer is to prevent degradation of active compound and to provide controlled release of protected ingredient under defined conditions. Modern food technology offers numerous solutions for encapsulation of food ingredients, plant extracts, microorganism cells, etc. Also, there are numerous available carrier materials that could be used for specific demand. Encapsulation is complex process and application of encapsulation techniques in the food production requires knowledge from different areas of science. The aim of this review is to summarize different encapsulation processes that are already applied in food technology as well as those that are under development. This paper analyses current experience in the area of encapsulation for food industry. Several encapsulation procedures such as spray drying, fluid bed coating, encapsulation in polymer particles, coacervation and encapsulation in cyclodextrins were analyzed.Procesi inkapsulacije su intenzivno izučavani poslednjih godina kao moguća alternativa konvencionalnim tehnologijama u proizvodnji hrane. Inkapsulacija aktivnih komponenti hrane se bazira na formiranju omotača (ili više slojeva omotača) oko aktivne komponente korišćenjem odgovarajuće metode inkapsulacije. Uloga zaštitnog omotača je, s jedne strane da spreči degradaciju aktivne komponente, a sa druge strane da omogući kontrolisano otpuštanje zaštićenih komponenti pod određenim uslovima. Moderna proizvodnja hrane nudi brojna rešenja za inkapsulaciju komponenti hrane, biljnih ekstrakata, ćelija mikroorganizama, itd. Takođe, postoji veliki broj dostupnih materijala nosača koji mogu da zadovolje specifične zahteve. Inkapsulacija je složen proces i primena inkapsulacionih tehnika u proizvodnji hrane zahteva znanje iz različitih oblasti nauke. Cilj ovog rada je da objedini različita iskustva iz inkapsulacionih procesa koji se već koriste u prehrambenoj tehnologiji, kao i onih procesa koji su još u fazi razvoja. Ovaj rad daje analizu i dosadašnja iskustva u oblasti inkapsulacije za potrebe industrije hrane. Data je analiza nekoliko inkapsulacionih procedura kao što su sprej sušenje, oblaganje u fluidizovanom sloju, inkapsulacija u polimernim česticama, koacervacija i inkapsulacija u ciklodekstrine

Implementation of the electrohydrodynamics’ perfect dielectric model in OpenFOAM®

The electrohydrodynamics’ (EHD) perfect dielectric model was added into computational fluid dynamics (CFD) software OpenFOAM® in order to improve its usability for the EHD field and specifically for the mentioned model. Based on the investigated literature, it can be said that this is the most complete implementatiton of the said model. Two sets of numerical simulations with two different fluids are presented and analyzed. One set is one-dimensional. The other set is with a drop of one fluid surrounded by other fluid. Oscillations can be observed with certain expressions or calculation strategies for the electrostrictive force, and used for disregarding them. Results that are closer to analytical predictions can be obtained by using appropriate expression for the dielectric force. The electrostrictive force was implemented not only for nonpolar, but also for polar fluids, and it is shown that it might significantly influence the drop deformation. Calculated and analytically predicted drop deformations were close or comparable even up to around 0.25, what is significantly higher and different from a previous study made by other authors. Different expressions for the electric permittivity and usage of limiters for volume fractions were investigated. Conclusions from this paper can be transferred to more complicated models

The effect of a plasma needle on bacteria in planktonic samples and on peripheral blood mesenchymal stem cells

In this paper, we study the application of a plasma needle to induce necrosis in planktonic samples containing a single breed of bacteria. Two different types of bacteria, Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922), were covered in this study. In all experiments with bacteria, the samples were liquid suspensions of several different concentrations of bacteria prepared according to the McFarland standard. The second system studied in this paper was human peripheral blood mesenchymal stem cells (hPB-MSC). In the case of hPB-MSC, two sets of experiments were performed: when cells were covered with a certain amount of liquid (indirect) and when the cell sample was in direct contact with the plasma. Most importantly, the study is made with the aim to see the effects when the living cells are in a liquid medium, which normally acts as protection against the many agents that may be released by plasmas. It was found that a good effect may be expected for a wide range of initial cell densities and operating conditions causing destruction of several orders of magnitude even under the protection of a liquid. It was established independently that a temperature increase could not affect the cells under the conditions of our experiment, so the effect could those hPB-MSC that were not protected by a liquid, gas flow proved to produce a considerable effect, presumably due to poor adhesion of the cells, but in a liquid the effect was only due to the plasma. Further optimization of the operation may be attempted, opening up the possibility of localized in vivo sterilization

Kultivacija matičnih i progenitorskih ćelija hematopoeze iz kostne srži hrčka

Hamster, a hibernating animal, is an important experimental model in research on the influence of hypothermia on different physiological processes. A simple procedure for cultivation and identification of hamster hematopoetic stem cells (HSC) and hematopoetic progenitor cells (HPC) is a premise for a successful investigation upon hypothermia effects on hematopoiesis. The aim of this work was to evaluate the utilization of commercially available methylcellulose media (MC) and recombinant mouse and human cytokines for hamster HSC and HPC assays, in order to enable further studies on these cells. Hamster bone marrow mononuclear cells (BMMNC) were plated in MC containing cytokines that support mouse or human HPC growth. Also, BMMNC were resuspended in cytokine supplemented liquid media and incubated for 5 weeks with a four day monitoring of viable cell number. We demonstrated that hamster hematopoietic progenitor cells committed for erythroid lineage and myeloid lineage successfully formed recognizable colonies in both mouse and human MC, while multipotent progenitor cells formed colonies only in mouse MC. We also defined conditions for the evaluation of hamster HSC activity in liquid cultures, based on continuous 5 weeks HSC proliferation. The obtained results verify the utilization of mouse specific MC for further research on hamster HPC biology during hypothermia.Fiziološka hibernacija u koju hrčci ulaze prilikom izlaganja niskim temperaturama, čini ove životinje zanimljivim eksperimentalnim modelom za ispitivanje hematopoeze u uslovima hipotermije. Preduslov za ovo ispitivanje je postojanje jednostavne metode za kultivaciju i identifikaciju hematopoetskih ćelija hrčka. Cilj ovog rada je bio da se ispita mogućnost kultivacije progenitorskih ćelija hematopoeze hrčka u kompletnoj metil celulozi dizajniranoj za kultivaciju mišijih i humanih hematopoetskih ćelija, kao i da se odrede optimalni uslovi za kultivaciju matičnih ćelija hematopoeze hrčka u tečnoj kulturi. Mononuklearne ćelije kostne srži hrčka su posađene u metil celulozu i u tečnu kulturu. Oba medijuma su sadržala kombinacije rekombinantnih mišijih i/ili humanih citokina. Kolonije progenitorskih ćelija opredeljenih za mijelopoezu i opredeljenih za eritropoezu su se formirale u metil celulozi dizajniranoj za kultivaciju mišijih i humanih hematopoetskih ćelija, dok su se primitivnije kolonije sastavljene od oba tipa ćelija (mijeloidna i eritrocitna loza) formirale samo u metil celulozi dizajniranoj za kultivaciju mišijih hematopoetskih ćelija. Osim toga, populacija matičnih ćelija hematopoeze hrčka je proliferisala u tečnim kulturama tokom 5 nedelja bez znakova opadanja proliferativnog potencijala. Ova istraživanja pokazuju da se primenjene metode mogu uspešno koristiti za ispitivanje hematopoeze kod hrčka