Influence of Spreading and Contractility on Cell Detachment

Cell adhesion is a key phenomenon that affects fundamental cellular processes such as morphology, migration, and differentiation. In the current study, an active modelling framework incorporating actin cytoskeleton remodelling and contractility, combined with a cohesive zone model to simulate debonding at the cell–substrate interface, is implemented to investigate the increased resistance to detachment of highly spread chondrocytes from a substrate, as observed experimentally by Huang et al. (J. Orthop. Res. 21: 88–95, 2003). 3D finite element meshes of the round and spread cell geometries with the same material properties are created. It is demonstrated that spread cells with a flattened morphology and a larger adhesion area have a more highly developed actin cytoskeleton than rounded cells. Rounded cells provide less support for tension generated by the actin cytoskeleton; hence, a high level of dissociation is predicted. It is revealed that the more highly developed active contractile actin cytoskeleton of the spread cell increases the resistance to shear deformation, and subsequently increases the shear detachment force. These findings provide new insight into the link between cell geometry, cell contractility, and cell–substrate detachment.     

The influence of the nervous system on the composition of the blood

Summary Followed-up-after-discharge reactions were studied in the nervous system of laboratory animals in experimental anemia induced by phenylhydrazine. The method of the second blow with towing (Speranskii) was employed. It was possible to reproduce, to a certain degree, the blood picture characteristics of phenylhydrazine poisoning at the time when the blood picture almost reached its initial stage. It could particularly be reproduced in the line of the changes of processes of regeneration.The data which was thus obtained gave theoretical foundation to these phenomena, which are sometimes met in clinical practice as relepses of certain diseases of the blood system.Presented by Academician A. D. Speranskii     

The influence of blood transfusion on cellular immunity

To evaluate the effect of transfusion on immunity, we studied some immunological parameters in 14 uremic patients treated with 3 blood transfusions (5 with HLA-compatible and 9 with random transfusions). Before transfusions 8/14 patients were DNCB-negative; both spontaneous and active E-rosettes were below normal range. The parameters of humoral immunity (S-Ig, C3, C4, IC, CRP) were normal. After both the first and second transfusions an increase in T- and B-lymphocytes was found. The third transfusion led to a more pronounced and prolonged immunosuppression in patients treated with compatible transfusions than in those treated with random transfusions. Our findings suggest that blood transfusion--HLA-compatible transfusion in particular--results in an impairment of the lymphocyte role.     

电针对禁食犬心肌收缩性的影响

本实验观察了禁食后机体能量缺乏时犬心肌收缩性的改变及其电针效应,结果表明,禁食组等容收缩相心肌收缩性参数及心肌节段张力参数均较正常组各相应值显著降低;而电针组在电针后,上述各项参数均见明显增加,提示禁食后犬心肌收缩性明显受损,电针则可改善禁食后受损的心肌收缩性。     

The influence of blood sample treatment on plasma potassium concentrations in avian blood

Plasma potassium concentrations were determined in racing pigeons (Columba livia domestica), chickens (Gallus domesticas) and man (Homo sapiens) after different storage times of uncentrifuged blood samples at room temperature. In the pigeon plasma potassium concentrations declined rapidly. After 10 min the reduction was 9.5% and declined by 65% after 120 min. No further reduction was noted up to 24 hours. In chickens decreases were also noted but were smaller overall with a 29% decrease being noted after 2 hours. No significant changes of plasma potassium concentrations in human blood were found during the first 2 hours of storage. The need to describe the treatment of blood after sampling is indicated. It is concluded that for most blood chemical measurements plasma is preferred to serum and blood samples should be centrifuged within minutes of sampling.