Thymidine Catabolism as a Metabolic Strategy for Cancer Survival

Thymidine phosphorylase (TP), a rate-limiting enzyme in thymidine catabolism, plays a pivotal role in tumor progression; however, the mechanisms underlying this role are not fully understood. Here, we found that TP-mediated thymidine catabolism could supply the carbon source in the glycolytic pathway and thus contribute to cell survival under conditions of nutrient deprivation. In TP-expressing cells, thymidine was converted to metabolites, including glucose 6-phosphate, lactate, 5-phospho-α-D-ribose 1-diphosphate, and serine, via the glycolytic pathway both in vitro and in vivo. These thymidine-derived metabolites were required for the survival of cells under low-glucose conditions. Furthermore, activation of thymidine catabolism was observed in human gastric cancer. These findings demonstrate that thymidine can serve as a glycolytic pathway substrate in human cancer cells

Absorption of Scintillation Light in a 100 ℓ\ell Liquid Xenonγ\gamma Ray Detector and Expected Detector Performance

An 800L liquid xenon scintillation $\gamma$ ray detector is being developed for the MEG experiment which will search for $\mu^+\to\mathrm{e}^+\gamma$ decay at the Paul Scherrer Institut. Absorption of scintillation light of xenon by impurities might possibly limit the performance of such a detector. We used a 100L prototype with an active volume of 372x372x496 mm$^3$ to study the scintillation light absorption. We have developed a method to evaluate the light absorption, separately from elastic scattering of light, by measuring cosmic rays and $\alpha$ sources. By using a suitable purification technique, an absorption length longer than 100 cm has been achieved. The effects of the light absorption on the energy resolution are estimated by Monte Carlo simulation.Comment: 18 pages, 10 figures (eps). Submitted to Nucl. Instr. and Meth.

Thymidine catabolism promotes NADPH oxidase-derived reactive oxygen species (ROS) signalling in KB and yumoto cells

Thymidine phosphorylase (TP) is a rate-limiting enzyme in the thymidine catabolic pathway. TP is identical to platelet-derived endothelial cell growth factor and contributes to tumour angiogenesis. TP induces the generation of reactive oxygen species (ROS) and enhances the expression of oxidative stress-responsive genes, such as interleukin (IL)-8. However, the mechanism underlying ROS induction by TP remains unclear. In the present study, we demonstrated that TP promotes NADPH oxidase-derived ROS signalling in cancer cells. NADPH oxidase inhibition using apocynin or small interfering RNAs (siRNAs) abrogated the induction of IL-8 and ROS in TP-expressing cancer cells. Meanwhile, thymidine catabolism induced by TP increased the levels of NADPH and intermediates of the pentose phosphate pathway (PPP). Both siRNA knockdown of glucose 6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme in PPP, and a G6PD inhibitor, dihydroepiandrosterone, reduced TP-induced ROS production. siRNA downregulation of 2-deoxy-D-ribose 5-phosphate (DR5P) aldolase, which is needed for DR5P to enter glycolysis, also suppressed the induction of NADPH and IL-8 in TP-expressing cells. These results suggested that TP-mediated thymidine catabolism increases the intracellular NADPH level via the PPP, which enhances the production of ROS by NADPH oxidase and activates its downstream signalling

Review on Superconducting Materials

Short review of the topical comprehension of the superconductor materials classes Cuprate High-Temperature Superconductors, other oxide superconductors, Iron-based Superconductors, Heavy-Fermion Superconductors, Nitride Superconductors, Organic and other Carbon-based Superconductors and Boride and Borocarbide Superconductors, featuring their present theoretical understanding and their aspects with respect to technical applications.Comment: A previous version of this article has been published in \" Applied Superconductivity: Handbook on Devices and Applications \", Wiley-VCH ISBN: 978-3-527-41209-9. The new extended and updated version will be published in \" Encyclopedia of Applied Physics \", Wiley-VC

ハンドアシスト法で腹腔鏡下脾摘術を施行した遺伝性球状赤血球症による脾腫の1例

良性脾疾患に対して,腹腔鏡下脾臓摘出術がしばしば施行されるようになったが,その手技は複雑で難易度が高い.このため脾腫では開腹手術が通常は選択されている.最近,術者の片手を挿入するハンドアシスト法(hand-assisted laparoscopic surgery:HALS)が腹腔鏡下手術に導入され,その有用性が検討されはじめている.今回,34歳女性の遺伝性球状赤血球症の脾腫症例に対してHALSを用いて脾摘術を施行した.上腹部にHALS用の小切開をおき,この創より短胃動静脈の切離を行い,左手を挿入した気腹後に後腹膜よりの脾の剥離と脱転,脾門部の切離を通常の腹腔鏡下脾摘術と同様に行った.脾臓の重量は620gであった.腫大した脾の把持や圧排に左手を用いているので,容易かつ安心して行うことができた.HALSは手術侵襲の増加は軽度であり,脾臓の把持や術野の展開における有用性を考慮すると,通常の脾摘に際しても有用な選択肢の一つになると考えられる.Recently, laparoscopic splenectomy has been frequently performed for hematologic diseases, but its technique is complex and difficult. For that reason, open surgery is usually employed for patients with splenomegaly. Meanwhile hand-assisted laparoscopic surgery (HALS) is a newly developed technique that has been introduced into laparoscopic surgery and the evaluation of its usefulness has started. We successfully performed a hand-assisted laparoscopic splenectomy for splenomegaly due to hereditary spherocytosis in a 34-year-old woman. At surgery we created a small vertical midline incision on the upper abdomen, and dissected the short gastric vessels through this incision. After that the left hand was inserted through this incision and held the spleen in a satisfactory position while a splenectomy was carried out using laparoscopic tools in a conventional manner in the pneumoperitoneum. The spleen weighted 620 g. This procedure allows the surgeon to use his or her hand in the pneumoperitoneum so that he can hold the spleen easier and safer than totally laparoscopic approaches. HALS has facilitated the laparoscopic splenectomy with an advantage of minimally invasive surgery. We consider that HALS is a useful method for both patients with and without splenomegaly

ハンドアシスト法で腹腔鏡下脾摘術を施行した遺伝性球状赤血球症による脾腫の1例

良性脾疾患に対して,腹腔鏡下脾臓摘出術がしばしば施行されるようになったが,その手技は複雑で難易度が高い.このため脾腫では開腹手術が通常は選択されている.最近,術者の片手を挿入するハンドアシスト法(hand-assisted laparoscopic surgery:HALS)が腹腔鏡下手術に導入され,その有用性が検討されはじめている.今回,34歳女性の遺伝性球状赤血球症の脾腫症例に対してHALSを用いて脾摘術を施行した.上腹部にHALS用の小切開をおき,この創より短胃動静脈の切離を行い,左手を挿入した気腹後に後腹膜よりの脾の剥離と脱転,脾門部の切離を通常の腹腔鏡下脾摘術と同様に行った.脾臓の重量は620gであった.腫大した脾の把持や圧排に左手を用いているので,容易かつ安心して行うことができた.HALSは手術侵襲の増加は軽度であり,脾臓の把持や術野の展開における有用性を考慮すると,通常の脾摘に際しても有用な選択肢の一つになると考えられる.Recently, laparoscopic splenectomy has been frequently performed for hematologic diseases, but its technique is complex and difficult. For that reason, open surgery is usually employed for patients with splenomegaly. Meanwhile hand-assisted laparoscopic surgery (HALS) is a newly developed technique that has been introduced into laparoscopic surgery and the evaluation of its usefulness has started. We successfully performed a hand-assisted laparoscopic splenectomy for splenomegaly due to hereditary spherocytosis in a 34-year-old woman. At surgery we created a small vertical midline incision on the upper abdomen, and dissected the short gastric vessels through this incision. After that the left hand was inserted through this incision and held the spleen in a satisfactory position while a splenectomy was carried out using laparoscopic tools in a conventional manner in the pneumoperitoneum. The spleen weighted 620 g. This procedure allows the surgeon to use his or her hand in the pneumoperitoneum so that he can hold the spleen easier and safer than totally laparoscopic approaches. HALS has facilitated the laparoscopic splenectomy with an advantage of minimally invasive surgery. We consider that HALS is a useful method for both patients with and without splenomegaly

胆管癌を合併した輪状膵の1例

胆管癌を合併した輪状膵の1例を経験した.症例は48歳男性で,急性胆嚢炎,閉塞性黄疸の診断で,近医で経皮経肝胆嚢ドレナージを施行後,紹介入院した.経皮経肝胆嚢ドレナージチューブ造影では下部胆管の全周性狭窄と壁硬化像を認め,更に,十二指腸の右側へ向かう膵管が造影された.低緊張性十二指腸造影では下行脚の限局性狭窄と口側腸管の拡張を認め,またcomputed tomographyでは十二指腸下行脚を取り囲む膵組織の存在が確認され輪状膵と診断した.下部胆管狭窄に対して悪性所見を強く疑い,手術を行った.術中迅速病理診断で胆管癌を確認し,手術は,幽門輪温存膵頭十二指腸切除,D,廓清を施行した.腫瘍は平坦浸潤型で,低分化な成分が混在し,胆管壁を浸潤性に増殖する中分化型腺癌であった.術後41日目に軽快退院し,3年後の現在,再発の徴候を認めていない.本邦報告例151例の成人型輪状膵を集計したところ,悪性腫瘍の合併は20例(13.2%)に認められ,このうち15例(75.0%)が膵胆道系の悪性腫瘍であった.輪状膵は膵胆道系の悪性腫瘍の合併が多いことを考えると,輪状膵の確定診断後は系統的な膵,胆道系の精査を行い,悪性腫瘍の存在の有無を確認することが必要と思われた.We experienced the case of a 48-year-old man suffering from an annular pancreas complicated with carcinoma of the bile duct. After the patient received percutaneous transhepatic gallbladder drainage (PTGBD) at a nearby hospital based on a diagnosis of acute cholecystitis and obstructive jaundice, he was referred to our hospital and admitted. Cholangiography performed by infusing a contrast medium through the PTGBD tube showed circumferential stenosis and parietal hardening of the lower bile duct and a pancreatic duct running to the right side of the duodenum. Hypotonic duodenography demonstrated stenosis localized in the descending part and dilatation of the intestinal tract on the oral side. Computed tomography (CT) showed the pancreatic tissue encircling the descending part of the duodenum. Based on these findings, he was diagnosed as having an annular pancreas with carcinoma of the bile duct. A surgical operation was performed because the stenosed site in the lower bile duct was strongly suspected of malignancy. The lesion was confirmed to be carcinoma of the bile duct through rapid intraoperative pathological examination, and pyloruspreserving pancreatoduodenectomy (PpPD) and D2 dissection were performed. The tumor, a flat, infiltrative type with intermingling, poorly differentiated components, was diagnosed as a moderately differentiated adenocarcinoma with infiltrative growth into the biliary wall. The patient remitted and was discharged on postoperative day 41. Now, three years after surgery, he shows no evidence of relapse. When we analyzed 151 cases of adult annular pancreas reported in Japan, 20 cases (13.2%) were found to be complicated with malignant tumors. Of these 20 cases, 15 (75.0%) had malignant tumors of the pancreatobiliary system. In view of the high incidence of malignant tumors of the pancreatobiliary system in patients with annular pancreas, it is imperative to rule out the presence of malignant tumors in these patients by systematically carrying out precise examinations of the pancreatobiliary system as soon as a definite diagnosis of annular pancreas is reached