Genetic comparison of mouse lung telocytes with mesenchymal stem cells and fibroblasts

Telocytes (TCs) are interstitial cells with telopodes – very long prolongations that establish intercellular contacts with various types of cells. Telocytes have been found in many organs and various species and have been characterized ultrastructurally, immunophenotypically and electrophysiologically ( www.telocytes.com ). Telocytes are distributed through organ stroma forming a three‐dimensional network in close contacts with blood vessels, nerve bundles and cells of the local immune system. Moreover, it has been shown that TCs express a broad range of microRNAs, such as pro‐angiogenic and stromal‐specific miRs. In this study, the gene expression profile of murine lung TCs is compared with other differentiated interstitial cells (fibroblasts) and with stromal stem/progenitor cells. More than 2000 and 4000 genes were found up‐ or down‐regulated, respectively, in TCs as compared with either MSCs or fibroblasts. Several components or regulators of the vascular basement membrane are highly expressed in TCs, such as Nidogen, Collagen type IV and Tissue Inhibitor of Metalloproteinase 3 (TIMP3). Given that TCs locate in close vicinity of small vessels and capillaries, the data suggest the implication of TCs in vascular branching. Telocytes express also matrix metalloproteases Mmp3 and Mmp10, and thus could regulate extracellular matrix during vascular branching and de novo vessel formation. In conclusion, our data show that TCs are not fibroblasts, as the ultrastructure, immunocytochemistry and microRNA assay previously indicated. Gene expression profile demonstrates that TCs are functionally distinct interstitial cells with specific roles in cell signalling, tissue remodelling and angiogenesis.     

Primary sideroblastic anemia masked by bleeding.

A patient with characteristic features of iron deficiency was unexpectedly found to have circulating siderocytes. Bone marrow iron stain at this time showed absence of both hemosiderin and ringed sideroblasts; electron microscopy revealed absence of mitochondrial iron loading but presence of cytoplasmic ferritin in normoblasts. Replenishment of iron stores led to development of typical sideroblastic anemia. These observations suggest that increased percentage of siderocytes in otherwise typical iron deficiency anemia may signify the presence of a sideroblastic process masked by iron deficiency due to bleeding.     

Amperometric study of the inhibitory effect of carboxylic acids on tyrosinase

A tyrosinase-modified Pt electrode, based on physical entrapment of the enzyme in agar–agar gel, was constructed and used to investigate the inhibitory effect of six carboxylic acids. At an applied potential of −50 mV versus saturated calomel electrode (SCE), the bioelectrode develops a fast, steady state response, linearly correlated with the phenol concentration up to 10 mg/l, with a sensitivity of 3.7 nA l/mg. A kinetic analysis of the amperometric response to phenol, recorded in the absence and in the presence of carboxylic acids (benzoic, 3-bromobenzoic, 4-ethylbenzoic, acetic, phenylacetic, 2-naphthylacetic acids), revealed that for the first four compounds the inhibition process corresponds to an uncompetitive one. Using the Lineweaver–Burk linearization the inhibition constants as well as the inhibition coefficients were calculated for the strong inhibitors: benzoic, 3-bromobenzoic, 4-ethylbenzoic and acetic acids.