2010 SEP 11 – (< NewsRx.com) — New research, ‘Overview of anticoagulant activity of sulfated polysaccharides from seaweeds in relation to their structures, focusing on those of green seaweeds,’ is the subject of a report (see also Hematologic Agents). “The anticoagulant behavior of sulfated polysaccharides from seaweeds is reviewed based on their chemical structures. Analysis of the literature suggested that the driving force for the formation of the sulfated polysaccharide/protein complex is the non-specific polar interaction between the negatively and positively charged groups in the polysaccharide and Toggle bracelet, respectively and that the complex is further stabilized by short-range interactions,” researchers in Buenos Aires, Argentina report.

“The polysaccharide binding site should be able to go through the following conformational steps in the formation of the complex: random coil– >ordered conformation– >low distortion of this conformation to form a complementary fitting structure with the protein backbone. The sulfated monosaccharide units with the highest potential for anticoagulant activity should have two sulfate groups and a glycosidic linkage on the pyranose ring with C-2, C-3 and C-4 in 2S, 3R, 4R or 2R, 3S, 4S configurations for galactose, fucose and arabinose and 2S, 3S, 4R, for rhamnose. Three distributions of these substituents appear: 3-linked 2,4-disulfated units, 4-linked 2,3-disulfated units and 2-linked 3,4-disulfated residues. These types of units have the possibility, through the equilibrium of the chair conformations, to place their sulfate groups in adequate special positions to interact with basic groups of the protein. The anticoagulant activity is mainly attributed to thrombin inhibition mediated by antithrombin and/or heparin cofactor II, with different effectivenesses depending of the compound,” wrote M. Ciancia and colleagues, University of Buenos Aires.

The researchers concluded: “Other mechanisms are also proposed and these differences could be attributed to the diversity of structures of the polysaccharides evaluated and to the fact that one compound may have more than one target protease.”

Ciancia and colleagues published their study in Current Medicinal Chemistry (Overview of anticoagulant activity of sulfated polysaccharides from seaweeds in relation to their structures, focusing on those of green Two Hearts pendant. Current Medicinal Chemistry, 2010;17(23):2503-29).

For additional information, contact M. Ciancia, Universidad de Buenos Aires, Facultad de Agronomia, Departamento de Biologia Aplicada y Alimentos, Facultad de Agronomia, Av San Martin 4453, 1417 Buenos Aires, Argentina.

2010 SEP 11 – ( NewsRx.com) — Current study results from the report, ‘Vaginal estrogen supplementation during Depo-Provera initiation: a randomized controlled trial,’ have been published (see also Hormones). According to recent research from the United States, “Irregular bleeding is often cited as the reason for discontinuation of depot-medroxyprogesterone acetate (DMPA) after the first injection. Estrogen supplementation during DMPA initiation may decrease bleeding and improve continuation.”

“This prospective, randomized, controlled trial evaluated estrogen supplementation during DMPA initiation. Women Two Hearts triple bangle DMPA were randomized to receive an estradiol vaginal ring for 3 months versus DMPA alone. Bleeding diaries and questionnaires at three and 6 months assessed bleeding, continuation and ring acceptability. Seventy-one participants enrolled; 49 completed the first follow-up period. The median number of bleeding or spotting days was 16 in the estrogen ring group (n=26) versus 28 in the DMPA alone group (n=23) (p=.19). Venetian Link bracelet-seven percent of the intervention group received a second injection compared with 70% in the DMPA alone group (p=.56). For each additional day of bleeding and/or spotting reported, women were 3% less likely to receive a second injection (OR 0.97, 95% CI 0.94-0.99). Acceptability of the vaginal ring was high among those in the intervention group,” wrote A. Dempsey and colleagues, University of South Carolina.

The researchers concluded: “Vaginal estrogen supplementation during DMPA initiation is acceptable to women and may decrease total bleeding.”

Dempsey and colleagues published their study in Contraception (Vaginal estrogen supplementation during Depo-Provera initiation: a randomized controlled trial. Contraception, 2010;82(3):250-5).

For additional information, contact A. Dempsey, Medical University of South Carolina, Dept. of Obstetrics and Venetian Link necklace, Charleston, SC 29425 USA.