Browsing by Subject "Cell Differentiation"

Now showing 1 - 3 of 3

Open Access
Application of the Ugi reaction with multiple amino acid-derived components: Synthesis and conformational evaluation of piperazine-based minimalist peptidomimetics
(Royal Society of Chemistry, 2015) Stucchi, M.; Cairati, S.; Cetin-Atalay, R.; Christodoulou, M.S.; Grazioso G.; Pescitelli G.; Silvani, A.; Yildirim, D.C.; Lesma G.
The concurrent employment of α-amino acid-derived chiral components such as aldehydes and α-isocyanoacetates, in a sequential Ugi reaction/cyclization two-step strategy, opens the door to the synthesis of three structurally distinct piperazine-based scaffolds, characterized by the presence of l-Ala and/or l-Phe-derived side chains and bearing appropriate functionalities to be easily applied in peptide chemistry. By means of computational studies, these scaffolds have been demonstrated to act as minimalist peptidomimetics, able to mimic a well defined range of peptide secondary structures and therefore potentially useful for the synthesis of small-molecule PPI modulators. Preliminary biological evaluation of two different resistant hepatocellular carcinoma cellular lines, for which differentiation versus resistance ability seem to be strongly correlated with well defined types of PPIs, has revealed a promising antiproliferative activity for selected compounds. © The Royal Society of Chemistry 2015.
Open Access
Polymorphism of spermatocytic seminoma. A morphometric study
(Hindawi Publishing Corporation, 1994) Frasik, W.; Okoń, K.; Sokołowski, A.
Spermatocytic seminoma (SS) is one of the testicular tumours. It is distinguished from other germ cell neoplasms by a special type of polymorphism. The aim of the present study was a morphometric analysis (Microplane II image system) of this phenomenon. In histological slides we measured the profile area of nuclei in about 500 adjacent cells. The basic material consisted of 12 cases (c.) of infiltrating SS, and the comparative material included intracanalicular SS (IcSS-1c.), other types of seminoma - typical (TS-2 c.), anaplastic (AS-2c.) and spermatogenesis in an elderly man (Sg-1 c.). We carried out a statistical analysis of the populations of cellular nuclei: we determined nuclear population similarities and differences, as well as their relation to various types of standard distributions such as Erlang, gamma, lognormal, normal and Weibull. Part of the SS histograms including IcSS showed similarities. The mean value of the profile area range from 32.5 to 56.5 μm2. In other types of seminomas this value was much higher. The Kolmogorov-Smirnov two-sample test showed differences between the compared nuclear populations. Lack of the differences was found only between certain SS (including IcSS). The results of comparisons of the populations studied with standard distributions showed that the analysed nuclear populations can be successfully described by more than one theoretical distribution. However, among the spermatocytic seminomas analysed, in contrast to TS and AS, we found distributions not corresponding to any of the standard distributions. The results of our findings argue also against the occurrence of haploid nuclei in SS cells. In slides from SS there were forms much larger than the nuclei of spermatocytes in Sg. In combination with the data concerning ploidy of the neoplasm we postulate that SS nuclear polymorphism is dependent both on maturation and atypia.
Open Access
Texturing of titanium (Ti6Al4V) medical implant surfaces with MHz-repetition-rate femtosecond and picosecond Yb-doped fiber lasers
(Optical Society of American (OSA), 2011) Erdoǧan, M.; Öktem, B.; Kalaycioǧlu H.; Yavaş, S.; Mukhopadhyay P.K.; Eken, K.; Özgören, K.; Aykaç, Y.; Tazebay, U.H.; Ilday F.O.
We propose and demonstrate the use of short pulsed fiber lasers in surface texturing using MHz-repetition-rate, microjoule- and sub-microjoule-energy pulses. Texturing of titanium-based (Ti6Al4V) dental implant surfaces is achieved using femtosecond, picosecond and (for comparison) nanosecond pulses with the aim of controlling attachment of human cells onto the surface. Femtosecond and picosecond pulses yield similar results in the creation of micron-scale textures with greatly reduced or no thermal heat effects, whereas nanosecond pulses result in strong thermal effects. Various surface textures are created with excellent uniformity and repeatability on a desired portion of the surface. The effects of the surface texturing on the attachment and proliferation of cells are characterized under cell culture conditions. Our data indicate that picosecond-pulsed laser modification can be utilized effectively in low-cost laser surface engineering of medical implants, where different areas on the surface can be made cell-attachment friendly or hostile through the use of different patterns. © 2011 Optical Society of America.