Binding of Stimuli-Responsive Ruthenium Aqua Complexes with 9-Ethylguanine.

Stimuli-responsive ruthenium complexes proximal- and distal-[Ru(C10tpy)(C10pyqu) OH2]2+ (proximal-1 and distal-1; C10tpy = 4'-decyloxy-2,2':6',2″-terpyridine and C10pyqu = 2-[2'-(6'-decyloxy)-pyridyl]quinoline) were experimentally studied for adduct formation with a model DNA base. At 303 K, proximal-1 exhibited 1:1 adduct formation with 9-ethylguanine (9-EtG) to yield proximal-[Ru(C10tpy)(C10pyqu)(9-EtG)]2+ (proximal-RuEtG). Rotation of the guanine ligand on the ruthenium center was sterically hindered by the presence of an adjacent quinoline moiety at 303 K. Results from 1H NMR measurements indicated that photoirradiation of a proximal-RuEtG solution caused photoisomerization to distal-RuEtG, whereas heating of proximal-RuEtG caused ligand substitution to proximal-1. The distal isomer of the aqua complex, distal-1, was observed to slowly revert to proximal-1 at 303 K. In the presence of 9-EtG, distal-1 underwent thermal back-isomerization to proximal-1 and adduct formation to distal-RuEtG. Kinetic analysis of 1H NMR measurements showed that adduct formation between proximal-1 and 9-EtG was 8-fold faster than that between distal-1 and 9-EtG. This difference may be attributed to intramolecular hydrogen bonding and steric repulsion between the aqua ligand and the pendant moiety of the bidentate ligand..

An emergency hybrid procedure that combines endoscopic treatment with partial splenic embolization for bleeding esophagogastric varices.

Management of splenomegaly is important in the treatment of portal hypertension. We report 2 cases who were treated by an emergency hybrid procedure combining endoscopic treatment and partial splenic embolization (PSE) based on a new concept "splanchnic caput Medusae". Case 1 with refractory esophageal variceal bleeding due to alcoholic liver cirrhosis was treated by endoscopic injection sclerotherapy (EIS) with ligation and PSE at the same time. Case 2 with gastric variceal bleeding due to polycystic liver disease was treated by EIS using n-butyl-2-cyanoacrylate and PSE at the same time. Six days after the hybrid procedure, transjugular retrograde obliteration was added. In both cases, post-treatment 3D-CT reconstruction images revealed that the spleen-portal system reversed to almost normal form. We conclude that an emergency hybrid procedure combining endoscopic treatment and PSE is effective for patients with bleeding esophagogastric varices.