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

Morphometric analysis of mandibular canal: clinical aspects

Results of morphometric analysis of the mandibular canal (MC), carried out on 105 conserved mandibles, 70 being dentate and 35 edentate, was performed. The analysis was carried out on consecutive sections, at mutual intervals of 0.5 cm. In the mandibular ramus sections were carried out obliquely, approximately in the frontal plane, and horizontally, from mandibular foramen to the lowest region of the vertical part of the MC (all together two sections). In the mandibular corpus, consecutive transversal sections were carried out between existing teeth, or at mutual intervals of 0.5 cm in edentate regions.The obtained results pointed out the very close relationship between the MC and lingual cortical plate of the mandibular ramus. In its horizontal part, the average diameter of the MC was 2.6 mm. It was situated more lingually in the molar region; towards the front, it approached the vestibular cortical plate, being closest to it in the region of the second premolar. Similar relationships of the MC and both cortical plates existed in edentate jaws. Relationships of the MC and tooth root apices varied; however, the MC was closest to the apices of the third molar. Mesially from the mental foramen, a clearly defined incisive canal was present in 92% of the dentale mandibles, but only in 31% of the edentate ones. The nearest to the incisive canal was the apex of the first premolar.The authors point out the importance of presented results in everyday practice, especially in oral and maxillofacial surgery. Having in mind the existing relationship between the MC and neighbouring structures, it is possible to avoid the injury of its content during several oral surgical procedures in mandibular ramus and corpus.L’analyse morphométrique du canal mandibulaire (CM) a été faite sur 105 mandibules conservées. Parmices mandibules, 70 étaient partiellement édentées et 35 totalement édentées. Les distances du CM de la couche compacte osseuse de la mandibule et des apex des racines dentaires ont été mesurées sur les coupes successives pratiquées à une distance de 0,5 cm. Dans la région de la branche montante mandibulaire les coupes successives ont été pratiquées suivant le plan horizontal, de l'orifice postérieur du canal mandibulaire à la terminaison de la partie verticale du CM. La région du corps mandibulaire a été traitée par des coupes verticales. Ces sections ont été faites successivement à travers l’espace entre chaque deux dents ou à une distance de 0,5 cm dans les régions édentées.Les résultats obtenus montrent que le CM se dirige obliquement de haut en bas et en avant, très proche de la lame osseuse linguale. Dans la partie horizontale son diamètre est de 2,6 mm en moyenne. Dans la région des dents molaires le CM est très proche de la lame osseuse linguale; en cheminant en avant, le CM s’approche de la lame osseuse buccale dont il est le plus proche dans la région de la P2. Dans les mandibules édentées, le CM a des rapports semblables.La distance du CM des apex des racines dentaires est variable, pourtant il est le plus proche des apex des racines de la M3. Mésialement du trou mentonnier, le canal incisif était clairement individualisé dans 92% des mandibules avec la denture conservée, et dans 31% des mandibules édentées. La première prémolaire était la plus proche du canal incisif.Les auteurs montrent l’importance des résultats présentés pour la stomatologie clinique, surtout pour la chirurgie orale et maxillofaciale. Compte tenu des rapports du CM avec les structures voisines on peut éviter des lésions de son contenu au cours de certaines interventions chirurgicales sur la branche montante et sur le corps de la mandibule

Antioxidant Capacities and Phenolic Levels of Different Varieties of Serbian White Wines

The biologically active compounds in wine, especially phenolics, are responsible for reduced risk of developing chronic diseases (cardiovascular disrease, cancer, diabetes, etc.), due to their antioxidant activities. We determined the contents of total phenolics (TP) and total flavonoids (TF) in selected Serbian white wines by colorimetric methods. Total antioxidant activity (TAA) of the white wines was analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay. Međaš beli had the highest content of TP, TF and TAA. The radical scavenging capacity (RSC) and total antioxidant activity (TAA) of white wines were 15.30% and 1.055 mM Trolox equivalent, respectively. Total phenolic (TP) and total flavonoid (TF) contents in white wines ranged from 238.3 to 420.6 mg gallic acid equivalent per L of wines and 42.64 to 81.32 mg catechin equivalent per L of wines, respectively. A high and significant correlation between antioxidant activity and total phenolic content was determined in wines (R2 = 0.968, p < 0.01). For the individual polyphenols determination we used a high performance liquid chromatography (HPLC)-diode array detection (DAD) technique. The majority of white wine polyphenols was represent by four hydroxycinnamic acids (HCAs)

Postural stability – a comparison between rowers and field sport athletes

Postural stability (PS) is an important function for maintaining equilibrium during periods of standing still, locomotion, and any motor activities that require high degree of balance. High PS is essential in different sports for the regulation of voluntary movement and for improving athletic physical condition and performance. Purpose: The purpose of this study was to compare the static PS of elite rowing athletes and field sport athletes. Methods: A total of 90 elite athletes (age: 23.9 ± 1.97 years; body height: 174.9 ± 8.9 cm; body weight: 67.7 ± 12.03 kg) were divided into Rowing (N = 47) and Field sport (N = 43) athlete groups. Static PS parameters were assessed with a static double-leg and single-leg standing stability test on a force plate platform. Results: The multivariate analysis of variance showed a general stability difference between the groups (F = 13.255; P ≤ 0.0001), in double leg stability (F = 16.735; P ≤ 0.0001), and left leg (F = 15.097; P ≤ 0.0001) stability parameters. When analyzing variables separately, significant statistical differences were observed in favor of the Rowing group in double leg sway area (p = 0.017; ES = −0.07), double leg center of force (COF) traveled way (p ≤ 0.0001; ES = −27.42), length function of surface (p ≤ 0.0001; ES = −26.86), right leg ML displacement (p = 0.030; ES = −0.46), left leg sway area (p = 0.030; ES = −0.44), left leg COF traveled way (p ≤ 0.0001; ES = −60.63), left leg AP displacement (p = 0.043; ES = −0.44). Conclusion: These results underline the differences in rowing and field sport athletes in terms of static PS. The characteristics of sport and competition may affect PS, and it is important to adjust training modalities for the required level of PS in every sport, especially in rowing

A validated model of GAG deposition, cell distribution, and growth of tissue engineered cartilage cultured in a rotating bioreactor

The purpose of this article is to review the different strategies for the delivery of plasmid DNA (pDNA)-based gene therapy. Plasmids are extrachromosomal DNA capable of being transmitted from cell to cell. They are supercoiled, circular covalently closed (ccc) strands of DNA capable of replication independently of host DNA and ranging from 5 to 400 kilo base pairs (kb) in size, depending on the size of the therapeutic gene insert

Picosecond polarised fluorescence studies of oxazine 4 motion and order in nematic and isotropic phases of 5-, 6- and 7-cyanobiphenyl

Picosecond fluorescence anisotropy and lifetime measurements are used to investigate the orientational dynamics and steady state order of the fluorescent probe oxazine 4 in the nematic and isotropic phases of 5, 6 and 7 cyanobiphenyl. Variation of the excitation polarisation angle beta with respect to the nematic director allows the preparation of both cylindrically symmetric and asymmetrically aligned probe distributions whose relaxation dynamics are sensitive to both theta and phi motions yielding two characteristic relaxation times: tau(20) (pure theta-diffusion) and tau(22) (predominantly phi-diffusion). Analysis of the fluorescence intensity decays for excitation polarisation angles of beta=0degrees and beta=54.7degrees allows a determination of the effect of local field and differential reflection losses without the measurement of sample refractive indices. A striking feature of oxazine 4 dynamics in the approach to the nematic-isotropic phase transition temperature (T-NI) is that whilst theta diffusion shows a characteristic Arrhenius temperature dependence, the rate of diffusion in the phi coordinate is reduced as the system becomes less ordered. In the isotropic phase over a 50degreesC temperature range above T-NI the fluorescence anisotropy is characterised by two correlation times consistent with restricted rotational diffusion (intra-domain relaxation tau(f)) within a slowly relaxing (pseudo-domain) structure (tau(s)). The temperature dependence of tau(f) and tau(s) was in good agreement with recent theoretical models for intra- and inter-domain relaxation

Les rapports du canal mandibulaire avec les faces externes du corps de la mandibule et risques qui en découlent de le léser

The investigations of relations and position of the mandibular canal (CM) were carried out on 80 mandibles (33 dentulous, 27 partly edentulous and 20 completely edentulous).The studies of relations of CM to the sides of mandibular body were accomplished by morphometric analysis of CM on consecutive transversal sections of mandibular body (54 preparations). The relation of the CM to be buccal or to the lingual side is expressed as the distance from the surface of the correspondent side of the mandibular body, which is shown in Table 1. According to these data, the position of the canal is at first proximate to the lingual side, and from the first molar tooth (M1) it approaches the buccal surface of the mandibular body.The position of the entire CM was determined by analysis of mandibular preparations (26) after removing the buccal osseous lamina. These investigations revealed that the position of the CM is predominantly buccal. Reconstruction of relations of the CM to the sides of mandibular body, according to the data obtained from transversal sections, and the real position of the CM are presented in Scheme I.The difference in direction lines of relations and of predominant position of the CM is a consequence of morphological characteristics of mandibular body.Le CM a été étudié sur 80 mandibules (dont 33 avec la denture conservée, 27 peu édentées et 20 totalement édentées). L’analyse morphométrique des rapports du CM a été faite sur les coupes frontales de la mandibule (54). La position du CM en entier a été examinée après la trépanation du corps mandibulaire (26 préparations). La reconstruction des rapports du CM d’après les données obtenues sur les coupes fait apparaître que le canal a d’abord une position linguale, ensuite il croise la M1 et se termine dans une position buccale. Dans la plupart des cas, le CM a, dans la majeure partie de son trajet, une position buccale à cause de la configuration caractéristique du corps mandibulaire