Inhibitory effects of vitamin K3 on DNA polymerase and angiogenesis

Vitamins play essential roles in cellular reactions and maintain human health. Recent studies have revealed that some vitamins including D3, B6 and K2 and their derivatives have an anti-cancer effect. As a mechanism, their inhibitory effect on cancer-related angiogenesis has been demonstrated. Vitamin K2 (menaquinones) has an anti-cancer effect in particular for hepatic cancer and inhibits angiogenesis. In the current study, we demonstrated that sole vitamin K3 (menadione) selectively inhibits the in vitro activity of eukaryotic DNA polymerase γ, which is a mitochondrial DNA polymerase, and suppresses angiogenesis in a rat aortic ring model. The anti-angiogenic effect of vitamin K3 has been shown in angiogenesis models using human umbilical vein endothelial cells (HUVECs) with regard to HUVEC growth, tube formation on reconstituted basement membrane and chemotaxis. These results suggest that vitamin K3 may be a potential anti-cancer agent like vitamin K2.This work was supported by the ‘Academic Frontier’ Project for Private Universities (Kobe-Gakuin University), matching fund subsidy from MEXT, 2006-2010, (K.M., H.Y. and Y.M.) and in part by a grant from the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT). K.M. acknowledges a Grant-in-Aid for Young Scientists (B) (No. 18700608) from MEXT. Y.M. also acknowledges a Grant-in-Aid for Young Scientists (A) (No. 19680031) from MEXT, and Grants-in-Aid from the Nakashima Foundation and the Foundation of Oil & Fat Industry, Kaikan, Japan

Volume Phase Transitions of Slide-Ring Gels

The volume phase transition of slide-ring gels with freely-movable cross-linking junctions was investigated. Ionic chemical gels with fixed cross-linking junctions undergo volume phase transitions when they have higher than the critical degree of ionization. However, the experimentally-observed critical ionization value for slide-ring gels is much higher than theoretical values for chemical gels. This difference indicates that the volume phase transition is significantly suppressed in slide-ring gels. The mesoscale structure at various swollen or shrunken states was also investigated by small angle X-ray scattering. Changes in the scattering patterns with shrinking slide-ring gels suggest microphase separation due to the sliding of cyclic molecules threaded along the axis of the polymer chains, which may suppress the volume phase transition. In addition, slide-ring gels absorbed/desorbed greater than equilibrium volumes in the shrinking/swelling processes and showed slow dynamics; these observations are also related to their sliding properties

Gastric metastasis from salivary duct carcinoma mimicking primary gastric cancer

Introduction: We present a very rare case of gastric metastasis mimicking primary gastric cancer in a patient who had undergone surgery for salivary duct carcinoma. Presentation of case: A 67-year-old man had been diagnosed as having right parotid cancer and had undergone a right parotidectomy and lymph node dissection. The histological diagnosis was salivary duct carcinoma. One year after the surgery, a positron emission tomography–computed tomography scan using fluorodeoxyglucose (FDG) revealed an abnormal uptake of FDG in the left cervical, mediastinal, paraaortic, and cardiac lymph nodes; stomach; and pancreas. On gastroduodenoscopy, there was a huge, easily bleeding ulcer mimicking primary gastric cancer at the upper body of the stomach. Biopsy revealed poorly differentiated adenocarcinoma. Therefore, we were unable to differentiate between the primary gastric cancer and the metastatic tumor using gastroduodenoscopy and biopsy. Because of the uncontrollable bleeding from the gastric cancer, we performed an emergency palliative total gastrectomy. On histological examination, the gastric lesion was found to be metastatic carcinoma originating from the salivary duct carcinoma. Discussion: In the presented case, we could not diagnose the gastric metastasis originating from the salivary duct carcinoma even by endoscopic biopsy. This is because the histological appearance of salivary duct carcinoma is similar to that of high-grade adenocarcinoma, thus, resembling primary gastric cancer. Conclusion: When we perform endoscopic examination of patients with malignant neoplasias, a possibility of metastatic gastric cancer should be taken into consideration