THE ELECTROPHORETIC MOBILITY OF HUMAN ERYTHROCYTES—WHOLE CELLS,GHOSTS, AND FRAGMENTS

The electrophoretic mobility of human red cell ghosts decreases in the presence of chicken serum. The decrease is not directly due to the presence of adsorbed material but to a change which is catalyzed by the foreign substance. It is suggested that abnormal serum materials resulting from disease may serve as catalysts. Fragments of broken cells have the same mobility as whole cells at first, then decrease even in pure salt suspension, while the whole cells remain essentially unchanged for hours. The results suggest that the slow change of whole cells, the change of ghosts in the presence of foreign serum, and the change of fragments are all manifestations of the same modification of structure or composition of the cell surface.     

WHY DOES BONE MATRIX CONTAIN NON-COLLAGENOUS PROTEINS? THE POSSIBLE ROLES OF OSTEOCALCIN,OSTEONECTIN, OSTEOPONTIN AND BONE SIALOPROTEIN IN BONE MINERALISATION AND RESORPTION

Four major non-collagenous bone proteins were localised by single and double immuno-histochemistry during de novo mineralisation and bone resorption. Both osteopontin and bone sialoprotein were localised ahead of the mineralisation front, suggesting that both proteins are necessary for the initiation of bone mineralisation. This supports previous suggestions that bone sialoprotein acts as a crystal nucleator. The role of osteopontin is less certain, but might be related to ensuring that only the right type of crystal is formed. Osteocalcin and osteonectin were not present in areas of first crystal formation, but were present in the fully mineralised matrix. Their role may be to control the size and speed of crystal formation. Osteopontin, bone sialoproteins and osteocalcin (but not osteonectin) were also present at reversal lines. Interpreting this localisation together with information from the literature, the following functions are suggested during resorption: Osteocalcin may act as a chemoattractant for osteoclasts, while both osteopontin and bone sialoprotein may facilitate the binding of osteoclasts via the arg-gly-asp motif.     

EFFECT OF REMOVAL OF EXTERNAL CALCIUM ON PHOSPHOINOSITIDE HYDROLYSIS IN CULTURED MYOTUBES OF EMBRYONIC CHICKEN

本工作研究了去细胞外钙对取自9天来亨鸡胚的培养肌管磷脂酰肌醇水解的影响。80 mmol/L K     

ON NEW MATERIAL OF STEGODON WITH RECOLLECTIONS OF THE CLASSIFICATION OF STEGODON IN CHINA

ReviseddiagnoaisCraniumcompressedanteroposteriorlyandhighvertical1y.Superiortuskslargeandstraight,nolowerincisors'Ridge-platesprogressiveIymulti-plyingfromsixtoelevenintheintermediateteeth,fromninetofifteenandhaIfilltheposteriormolars.Thereisamediancleftoritsvestigesintheanteriorridge-platesoftheprimitivespecies.Conesrapidlysubdividingbybinaryorternary.fissionintomultipleconelets(8-l2).Ridge-plateselevatingfrombrachyodonttosubhypsodont.Cementdevelopingintheval1eys.RemarksSarwar(l977)propose…     

BONE MARROW ASPIRATION—The Posterior Iliac Crest,an Additional Safe Site

The posterior iliac crest is a readily accessible site for bone marrow aspiration which is safe, psychologically less traumatic, and affords representative samples of bone marrow similar to those obtained from the sternum, the vertebral spine and the anterior iliac crest.