miR-29 Represses the Activities of DNA Methyltransferases and DNA Demethylases

Members of the microRNA-29 (miR-29) family directly target the DNA methyltransferases, DNMT3A and DNMT3B. Disturbances in the expression levels of miR-29 have been linked to tumorigenesis and tumor aggressiveness. Members of the miR-29 family are currently thought to repress DNA methylation and suppress tumorigenesis by protecting against de novo methylation. Here, we report that members of the miR-29 family repress the activities of DNA methyltransferases and DNA demethylases, which have opposing roles in control of DNA methylation status. Members of the miR-29 family directly inhibited DNA methyltransferases and two major factors involved in DNA demethylation, namely tet methylcytosine dioxygenase 1 (TET1) and thymine DNA glycosylase (TDG). Overexpression of miR-29 upregulated the global DNA methylation level in some cancer cells and downregulated DNA methylation in other cancer cells, suggesting that miR-29 suppresses tumorigenesis by protecting against changes in the existing DNA methylation status rather than by preventing de novo methylation of DNA.     

Amino acid sensing by impedance of porous monolith-type ion exchanger

A biological and chemical sensor with rapid response at the microlevel is required for health and environmental monitoring. To develop a high-performance sensor, we use a porous monolith-type ion exchanger having three-dimensional acceptors to sense chemical substances. This porous monolith-type ion exchanger has an open-cellular structure with 5-50-μm diameter pores. The concentration of amino acids in the solution can be detected by measuring the impedance of the monolith-type ion exchanger. The novel ion exchanger has a high-exchange rate and high-electrical conductivity compared with that of the conventional ion-exchange resins. It is found that the impedance of the porous ion exchanger varies widely, depending on the amino acids such as glycine, asparatic acid, lysine, and phenylalanine. The impedance of anion exchanger had the highest value for phenylalanine with a benzene ring. OH-ion conduction is suppressed possibly due to the phenylalanine molecules stabilized by the hydrophobic interaction with the anion exchanger. In addition, we succeeded in sensing amino acid ions with concentration as low as 10⁻⁷ mol. The porous ion exchanger has the potential of a high-performance device for biological and chemical sensing.     

Glomangioma of the ankle simulating injury to the flexor hallucis longus: a case report

The glomangioma is one of a group of benign tumors of glomus body origin. Commonly found in the distal extremities, they may present with pain, tenderness to palpation, and sensitivity to temperature. Histologically, varying proportions of glomus cells, as well as vascular and smooth muscle elements, are found. Complete surgical excision is usually curative. We report on a glomangioma of the ankle in a 12-year-old male patient that simulated injury to the flexor hallucis longus tendon.