Sensing mechanism for biothiols chemosensor DCO: roles of excited-state hydrogen-bonding and intramolecular charge transfer.

The biothiols sensing mechanism of (E)-7-(diethylamino)-3-(2-nitrovinyl)-2H-chromen-2-one (DCO) has been investigated using the density functional theory (DFT) and time-dependent DFT methods. The theoretical results indicate that the excited-state intermolecular hydrogen bonding (H-B) plays an important role for the biothiols sensing mechanism of the fluorescence sensor DCO. Multiple H-B interaction sites exist in DCO and in its Michael addition product DCOT, which then induce the formation of the H-B complexes with water molecules, DCOH2 and DCOTH4. In the first excited state, the intermolecular H-Bs between water molecule and DCO in DCOH2 are cooperatively and generally strengthened and thus induced the weak fluorescence emission of DCO, while the cooperative H-Bs between water molecule and DCOT in DCOTH4 are overall weakened and thus responsible for the enhanced fluorescence emission of DCOT. Moreover, the theoretical results suggest that the blue shift of the UV-Vis absorption spectrum of DCOT can be attributed to the relatively weak excited-state intramolecular charge transfer in DCOT compared to DCO.

Vasospasm after subarachnoid hemorrhage:diagnosis with MR angiography and CT angiography / 中国基层医药

Objective To evaluate the efficacy of MR angiogrphy(MRA) for detecting cerebral vasospasm after subarachnoid hemorrage(SAH) and compare it with spiral CT angiography(CTA).Methods Ten patients with SAH under MRA and CTA studies were performed within 24 hours after MRA,which was performed 5 to 10 days after SAH.Maximum intensity projection(MIP) images were produced for MRA and CTA studies.Five arterial locations were examined for spasm:the suprasellar internal carotid artery(ICA),the M1 and M2 segments of the middle cerebral artery(MCA),the A1 and A2 segments of the anterior cerebral artery(ACA).Vasospasm was cate- gorized as none,mild(50 % reduction).Results The overall correlation between MRA and CTA was 82 %(r=0.76),but it was better for proximal than distal lo- cations vessels.Agreement between MRA and CTA was greater for no spasm(89%) and severe spasm(100%)(r= 0.85～0.91)than for mild(56%)or moderate(67%)spasm(r=0.21～0.51).Conclusion MRA is highly accu- rate in the detecting no spasm or severe cerebral vasospasm in proximal arterial locations vessels;it is less accurate in detecting mild and moderate spasm in distal locations vessels.

Blood supply features and interventional therapy of pedunculated hepatocellular carcinoma / 介入放射学杂志

Objective To evaluate the blood supply features and effectiveness of arterial chemoembolization for pedunculated hepatocellular carcinoma.Methods Angiography and chemoembolization via supplying blood arteries of tumor were performed in five patients with pedunculated hepatocellular carcinoma.Interventional procedure was carried out with tumor vascular infusion of 350 mg hot elemene emulsion and tumor embolization by cisplantin-lipidol emulsion(cisplantin 60-80 mg+lipidol 8-15 ml)and glutin.Results Ten interventional procedures(TACE)were undertaken in 5 patients.Angiography showed that tumor blood supply mainly coming from collateral circulation adjacent to the tumors,but partially from hepatic artery.Tumor sizes decreased from 30% to 50% in 5 cases,and AFP declined in 4 cases after the treatment. Conclusion Pedunculated hepatocellular carcinoma possessing different blood supply features from intrahepatocellular carcinomas.But transarterial ehemoembolization is still an effective method of choice for this treatment.