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Biomedical subjects

M Kaibara

Publications and source records attributed to M Kaibara.

126 records · Page 7Linked to original sources
PubMed1971

Morphologic development of fetal rabbit lung and its acceleration with cortisol.

The influence of cortisol on the maturation of fetal lungs of rabbits has been studied. The normal developmental pattern of the various lobes is also documented and it is shown that there is a definite sequence of maturation among the five lobes of the lung. At a given gestational age, both upper lobes are consistently most mature. The right middle lobe is somewhat less mature while right and left lower lobes are least mature. The difference in the rate of maturation between the most advanced right apex and the least advanced base of lower lobes is as much as 1(1/2) days out of a total gestation of 30 days. Cortisol, injected into the fetuses 2 days prior to delivery, accelerated the overall maturation of the lung by about 1(1/2) days. The maturation of the type II epithelial cells also was accelerated and their inclusion bodies were more numerous than those of the controls. As reported elsewhere, prematurely delivered cortisol-injected rabbits of 26 to 28 days' gestation are more viable, breathe better and their lungs are better aerated when compared with control littermates. The surface activity of the alveolar lining of these animals is greater than that of the controls as indicated by higher ratios of bubble stability. These findings are apparently the results of accelerated maturation of the type II alveolar epithelial cells, which contain surfactant or its precursors as inclusions within the cytoplasm.

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PubMedDate not supplied

Rheological approach to the analysis of blood coagulation in endothelial cell-coated tubes: activation of the intrinsic reaction on the erythrocyte surface.

Coagulation of blood in cultured endothelial cell-coated tubes was examined using a rheological technique. Coagulation of recalcified, platelet-free plasma in contact with an endothelial cell monolayer did not occur within the experimental time period (more than 150 min). The endothelial cell surface did not activate the intrinsic coagulation reaction or the extrinsic coagulation reaction initiated by tissue factor. The time of onset of coagulation in platelet-free plasma supplemented with erythrocytes was nearly the same as that of whole blood (31.2 +/- 5.5 min), which was shorter than that for platelet-rich plasma (54.3 +/- 14.3 min) and platelet-free plasma supplemented with granulocytes (58.3 +/- 6.3 min). In factor VII-, XI- or XII-deficient, platelet-free plasma supplemented with erythrocytes, the time of onset of coagulation was about 30 min. The coagulation of factor IX-deficient, platelet-free plasma supplemented with erythrocytes, however, did not occur within the experimental time period. These data suggest that activation of factor IX on the erythrocyte surface is capable of activating the intrinsic coagulation system.

Adult↗
PubMedDate not supplied

Rheology of blood coagulation.

There have been a number of investigations on coagulation reactions of blood as well as on coagulation factors including fibrinogen and thrombin. With the progress of clotting, the viscosity and rigidity of blood increase, facts related to the clot structure of fibrin. Therefore, rheological measurements make it possible to investigate the process of blood clotting as well as the properties of the fibrin clot. In this paper, our rheological studies on blood coagulation are summarized. The network structure of fibrin clots formed under different conditions is discussed from the kinetic analysis of the change of dynamic rigidity modulus during clotting. Also it will be shown that rheological techniques make it possible to analyze the initial coagulation reaction of blood in contact with components constituting the vascular vessel. The analysis indicates that a coagulation factor in plasma is activated on the erythrocyte surface.

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PubMedDate not supplied

Development of a biologically active Guglielmi detachable coil for the treatment of cerebral aneurysms. Part I: in vitro study.

BACKGROUND AND PURPOSE: Stronger cellular adhesion on the surface of endovascular devices promotes accelerated healing of aneurysms. The purpose of this in vitro study was to study the cellular interaction on the surface of bioactive Guglielmi detachable coils (GDCs) after using the surface-modification technology, ion implantation. METHODS: Polystyrene (PS) dishes and platinum plates were used to simulate a GDC surface. They were treated with either simple collagen coating or collagen coating followed with ion implantation. Bovine endothelial cells (2-2.5 x 10(4) cells in 1 mL) were suspended in medium supplemented with 10% fetal bovine serum on the PS dishes or platinum plates. Five days after cell seeding, the strength of cell adhesion was evaluated by trypsin treatment and flow shear stress. The cell detachment from the PS and platinum surfaces was observed microscopically. RESULTS: Five days after cell seeding, both simple collagen-coated surfaces and collagen-coated ion-implanted surfaces showed uniform endothelial proliferation. After trypsin treatment, or under flow shear stress, stronger cell adhesion against chemical and flow shear stress was observed on the ion-implanted collagen-coated surface. In contrast, the endothelial cells were detached easily from the non-ion-implanted collagen-coated surface. CONCLUSION: Ion implantation in combination with protein coating improves the strength of surface cell adhesion when exposed to flow shear stress and proteolytic enzymes. Strong endothelial cell adhesion is reported to be important to achieve earlier endothelialization across the neck of an embolized aneurysm with bioactive GDCs. This new technology may improve long-term anatomic outcome in cerebral aneurysms treated with GDCs.

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