According to the level of selenium (Se) and methionine (Met) in diet, Wistar rats were randomly divided into 3 groups, group A (normal Se and normal Met); group B (Low Se and normal Met); group C (low Se and low Met). The animals were sacrificed after 8-week feeding. The results showed that the alteration of myocardial ultrastructure was slight in group B. Decreased activities of cytochrome oxidase and succinate dehydrogcnase of myocardial mitochonria and decreased activities of GSH-Px in the blood, heart and liver in group B were observed, as compared with those in group A. But the level of TBA was higher than that of group A.The above mentioned changes in group C were extremely apparent than group A or B, indicating both Se and Met deficiency in diet may concern the etiology of Keshan disease.

To evaluate the application of self-reinforced ploy-DL-lactide (SR-PDLLA) absorbable screws in the treatment of spongy bone and intra-articular fractures, the internal fixation with SR-PDLLA absorbable screw was performed on 58 cases,of which 25 were medial malleolus fractures, 14 condyle of humerus fractures, 9 tibial plateau fractures, 7 ulnar olecranon fractures, and 3 lateral malleolus fractures. Observations were made on the orthopaedic operation sites and overall conditions frequently and radiography was performed for periodic analysis. The results showed that SR-PDLLA absorbable screws were particularly effective and reliable, they had good biocompatibility in the treatment of spongy bone and intra-articular fractures and could be used safely in clinical practice.
Absorbable Implants ; Adolescent ; Adult ; Ankle Injuries ; surgery ; Bone Screws ; Child ; Female ; Fracture Fixation, Internal ; Fractures, Bone ; surgery ; Humans ; Humeral Fractures ; surgery ; Internal Fixators ; Lactic Acid ; chemistry ; Male ; Middle Aged ; Polyesters ; Polymers ; chemistry

D-psicose 3-epimerase (DPEase) is demonstrated to be useful in the bioproduction of D-psicose, a rare hexose sugar, from D-fructose, found plenty in nature. Clostridium cellulolyticum H10 has recently been identified as a DPEase that can epimerize D-fructose to yield D-psicose with a much higher conversion rate when compared with the conventionally used DTEase. In this study, the crystal structure of the C. cellulolyticum DPEase was determined. The enzyme assembles into a tetramer and each subunit shows a (β/α)(8) TIM barrel fold with a Mn(2+) metal ion in the active site. Additional crystal structures of the enzyme in complex with substrates/products (D-psicose, D-fructose, D-tagatose and D-sorbose) were also determined. From the complex structures of C. cellulolyticum DPEase with D-psicose and D-fructose, the enzyme has much more interactions with D-psicose than D-fructose by forming more hydrogen bonds between the substrate and the active site residues. Accordingly, based on these ketohexose-bound complex structures, a C3-O3 proton-exchange mechanism for the conversion between D-psicose and D-fructose is proposed here. These results provide a clear idea for the deprotonation/protonation roles of E150 and E244 in catalysis.
Binding Sites ; Biocatalysis ; Catalytic Domain ; Clostridium cellulolyticum ; enzymology ; Hexoses ; chemistry ; Manganese ; chemistry ; Protein Structure, Quaternary ; Racemases and Epimerases ; chemistry ; metabolism ; Substrate Specificity