Mild and Selective Hydrogenation of Unsaturated Compounds Using Mn/Water as a Hydrogen Gas Source.

A mild and highly selective reduction of alkenes and alkynes using Mn/water is described. The highly controlled generation of H2 allows the selective reduction of these compounds in the presence of labile functional groups under mild and environmentally acceptable conditions.

Exploring Short and Efficient Synthetic Routes Using Titanocene(III)-Catalyzed Reactions: Total Synthesis of Natural Meroterpenes with Trisubstituted Unsaturations.

The stereo- and regioselective total syntheses of OMe derivatives of the scarce bioactive meroterpenoids makassaric acid (1) and fascioquinol B (2) have been accomplished. The synthetic sequences are based on the following three efficient and selective catalytic reactions: Cu-catalyzed addition of Grignard compounds to an epoxide; a regioselective Barbier-type reaction, catalyzed by Cp2TiCl; and regio- and stereoselective bioinspired cyclization, also catalyzed by Cp2TiCl. These three key processes allow us to obtain the main skeletons of 1 and 2 in a few steps. The valuable synthetic proposal shown in this work provides fast access to scarce, structurally complex meroterpenes with promising biological activities, which are a sustainable source for later studies and applications in medicine.

Calpain, not caspase, is the causative protease for hypoxic damage in cultured monkey retinal cells.

PURPOSE: Cell death occurring in human retina during AMD, high IOP, and diabetic retinopathy could be caused by activation of calpain or caspase proteolytic enzymes. The purpose of the present study was to determine whether calpains and/or caspase-3 were involved in cell death during retinal hypoxia in a monkey model. METHODS: Dissociated monkey retinal cells were cultured for two weeks and subjected to 24-hour hypoxia/24-hour reoxygenation. TUNEL staining and immunostaining for Müller and photoreceptor markers were used to detect which retinal cell types were damaged. RESULTS: Culturing dissociated monkey retina cells for two weeks resulted in proliferation of Müller cells and maintenance of some rod and cone photoreceptor cells, as identified by vimentin, recoverin, and rhodopsin immunocytochemical staining. Hypoxia/reoxygenation increased the number of cells staining positive for TUNEL. Immunoblotting showed that the calpain-specific 145 kDa α-spectrin breakdown product (SBDP) increased in hypoxic cells, but no caspase-specific 120 kDa α-spectrin breakdown product was detected. TUNEL staining and proteolysis were significantly reduced in the retinal cells treated with 10 and 100 µM calpain inhibitor SNJ-1945. Caspase inhibitor, z-VAD, did not inhibit cell damage from hypoxia/reoxygenation. Intact pro-caspase-3 was in fact cleaved by activated calpain during hypoxia/reoxygenation to pre 29 kDa caspase-3 and 24 kDa inactive fragments. No 17 and 12 kDa fragments, which form the active caspase-3 hetero-dimer, were detected. Calpain-induced cleavage of caspase was inhibited by SNJ-1945. CONCLUSIONS: Calpain, not caspase-3, was involved in hypoxic damage in cultured monkey retinal cells.