Magnetic coupling in CuCr2X4 (X = S, Se) spinel compounds obtained via substitution of the chromium ions by nonmagnetic Sb or Al ions

Taking into account both the dc magnetic susceptibility and the magnetization measurements as well as the high-temperature expansion of the magnetic susceptibility procedure the hopping integrals and superexchange integrals for the first and second coordination sphere were evaluated. The two hopping integrals are positive and many times greater than the superexchange ones. The obtained results testify to that in the stoichiometric compounds under study the double-exchange magnetic interaction is the main mechanism responsible for very strong, ferromagnetic coupling. Using the total hopping integral B the bandwidth of mixed valence band of chromium ions was determined

In vitro analysis of the proliferation potential and colony forming efficiency of stem cells isolated from dental pulp (DPSC) and apical papilla (SCAP), cultured in standard and pro-mineralizing conditions

Introduction. Recent data point to unerupted third molars as a promising source of stem cells (SC). Tooth derived SC are clonogenic and present a capacity for self-renewal and colony formation. Additionally, an environmental stimulation induces an in vitro differentiation of SC into multiple lineages, including odontoblasts. Aim of the study. The aim of the study was to evaluate the in vitro potential for proliferation and colony formation by stem cells derived from both dental pulp and apical papilla cultured in both standard medium (control and primary group) and medium modified with ingredients that stimulate mineralization (experimental group). Material and methods. Right after odontectomy the dental pulp and apical papilla were digested with dispase and collagenase type I. DPSCs and SCAPs were sorted using anti STRO-1, CD146, CD34, CD45 antibodies by means of the MACS method. Thereafter, the cells from the initial and control groups were cultured in a standard medium. The medium of the experimental group was additionally modified with ingredients that stimulated mineralization. To assess the cells commitment, the rate of proliferation and colony formation were examined. Results. The analysis showed that SCAPs from all the examined groups proliferated faster and formed more numerous and larger colonies compared to DPSCs. Environmental stimulation reduced proliferation and the ability to form colonies in both the DPSCs and SCAPs lineages. Conclusion. Faster proliferation and a higher ability to form colonies indicates the lower commitment of SCAPs compared to DPSCs. Additionally, the slower proliferation of stem cells from the experimental group suggests their more advanced commitment and differentiation. Although the SCAPs and DPSCs present different degrees of maturation, both cell lineages seem to be promising sources of stem cells

K-RAS point mutation, and amplification of C-MYC and C-ERBB2 in colon adenocarcinoma.

The routine multidisciplinary management of colon cancer is based mainly on tumor staging, histology, grading and vascular invasion. In this approach, important individual information derived from molecular characteristics of the tumor may be missed, especially since significant heterogeneity of molecular aberrations in cancer cells has been observed, and recognition of every of relationships between them may be of value. K-RAS, C-MYC and C-ERBB2 are protooncogenes taking part in carcinogenesis and tumor progression in the colon. They influence cell proliferation, differentiation and survival. K-RAS point mutation, as well as amplification of C-MYC and C-ERBB2 were searched in 84 primary colon adenocarcinomas resected with curative intent. Multiplex polymerase-chain reaction and restriction fragment length polymorphism were performed to assess codon 12 K-RAS point mutation. Amplification of C-MYC and C-ERBB2 genes was evaluated by densitometry after agarose gel separation of the respective multiplex PCR products. No relation was found among mutated and/or amplified genes, and between searched molecular aberrations and pathoclinical features. In multivariate analysis, nodal status appeared to be the only independent prognostic indicator. In colon adenocarcinoma, codon 12 K-RAS point mutation and amplification of C-MYC and C-ERBB2 seem to occur independently in the process of tumor progression. Amplification of C-ERBB2 tends to associate with more advanced stage of disease. Concomitant occurrence of codon 12 K-RAS mutation, C-MYC and C-ERBB2 amplification was of no prognostic value in respect to survival

Influence of substitution of the chromium ions by the nonmagnetic Sb and Al ions on the magnetization processes in CuCr2X4 (X = S, Se) spinels

Both the dc and ac magnetic susceptibilities as well as magnetization measurements were used to study the influence of the dilution of the magnetic chromium subarray by nonmagnetic antimony and aluminium ions on the magnetization processes for four spinel families under investigation. Substitution of the chromium ions by the nonmagnetic Sb and Al ions in the compounds under study leads to the very hard magnetization in the case of the compounds with Sb and very easy magnetization in the compounds with Al. This effect is connected with the electronic configurations of the Sb and Al ions as well as with ionic radii of these cations

N-myc downstream regulated 1 gene and its place in the cellular machinery

The exact function of the protein product of N-myc downstream regulated 1 gene (NDRG1) is unclear. Depending on the tissue type the NDRG1 protein is localized in the cytoplasm, nucleus, mitochondrion or membranes. Moreover, the expression of NDRG1 may be altered by several factors such as hypoxia, heavy metals, DNA damage, hormones, oncogene, and tumor-suppressor genes. A number of studies emphasize the role of NDRG1 in cancerogenesis. Presumably NDRG1 participates in angiogenesis, metastases, and mechanisms leading to anti-cancer drug resistance. This review summarizes current knowledge about the NDRG1 gene and the position of NDRG1 protein in the cellular machinery. The role of NDRG1 in cancer pathogenesis and its possible usefulness as a prognostic factor for patients with cancer is also discussed