[Selective COX-2 inhibitor delays experimental gastric ulcer healing by stimulating gastric acid secretion in rats].

Objective: To observe the effect of selective cyclooxygenase-2 (COX-2) inhibitor on the healing of experimental gastric ulcer in rats and explore its mechanisms in light of gastric acid secretion.

Methods: Gastric ulcers were induced in rats by an application of acetic acid to the serosal surface of the anterior gastric body. The effects of selective COX-2 inhibitor, celecoxib, on the healing of gastric ulcer, the total acidity of gastric juice, the expressions of H+, K+-ATPase mRNA and protein, and the ultrastructure of the parietal cell were observed in comparison with the effects of normal saline.

Theoretical study of sheets formed by beta-peptides.

Structural and thermodynamic features of the sheets formed by beta-peptides have been studied by quantum mechanics calculations using peptide models. Calculations using dipeptide models indicate that the intrinsic hydrogen bond strength is great for both parallel and antiparallel sheets and that it is little affected by proper substituents. Heterochiral-beta(2,3)-peptides have much stronger sheet-forming propensity than other types of peptides because their favored backbone conformation is ideal for sheet formation.

Effect of nutrition intervention on antioxidant capacity and lipid peroxide in patients with bone marrow transplantation.

Objective: To study the effect of exogenous antioxidant vitamins on antioxidant capacity and lipid peroxide status in patients with bone marrow transplantation.

Methods: Nineteen bone marrow transplantation (BMT) recipients were randomly divided into experimental group (n=10), who received Vit C (300 mg/d) and Vit E (600 mg/d) consecutively 15 d before the initiation of pretreatment of BMT, and the control group (n=9), who received the same treatment only without prior vitamin administration. The levels of ferric-reducing ability of plasma (FRAP), plasma malondialdehyde (MDA), the activity of glutathione peroxidase (GSH-Px) in the blood and the red blood cell superoxide dismutase (RBC-SOD) were measured in both groups before and after the operation.