Biomedical subjects

Y Takashima

Publications and source records attributed to Y Takashima.

188 records · Page 11Linked to original sources

PubMedDate not supplied

Action of phenolic antioxidants on various active oxygen species.

The action of phenolic antioxidants, such as probucol, on various active oxygen species was investigated using luminol chemiluminescence and spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The various active oxygen species, including hydroxyl radicals (Fenton reaction), superoxide anions, singlet oxygen and hypochlorite ions were examined with phenolic antioxidants under aqueous and nonaqueous conditions. Probucol showed a quenching effect on both superoxide anions and hypochlorite ions in nonaqueous solution. However, it had no effect on hydroxyl radicals. alpha-Tocopherol, a natural phenolic antioxidant, showed a stronger quenching effect on superoxide anions and hypochlorite ions than probucol, and quenched hydroxyl radicals in nonaqueous solution. Furthermore, Trolox showed a quenching effect on all active oxygen species in both aqueous and nonaqueous solution. The antioxidants were studied under comparable conditions in a series of test systems and the reactivity profiles depicted as 'radar charts' which are helpful for characterizing antioxidant action.

Antioxidants↗

PubMedDate not supplied

Rat preference for food-related odors.

Preferences for food-related odors and the effects of fasting on those preferences were investigated during rat bar pressing for brief odor presentation. A rat was housed in an equilateral octagonal cage and had free access to food and water, except during fasting. Among 8 food-related odor substances (black pepper, cheese, coffee, milk, nut, peppermint, plum and orange), black pepper, milk and coffee were most preferred, and cheese was least preferred, but even the bar pressing rate for cheese was above the operant level. This data indicates that all 8 odors were preferred by rats, although there were different degrees of preference in individual animals. Fasting substantially increased the rate of bar pressing for odors and changed the odors preferences. This result was probably due to increased search for food and water. Since bar pressing was reinforced by nothing other than odor presentation, the results reveal inherent odor preferences of rats.

Animals↗

PubMedDate not supplied

Biological and immunogenic properties of rabies virus glycoprotein expressed by canine herpesvirus vector.

In order to evaluate whether canine herpesvirus (CHV) could be used as a live vector for the expression of heterologous immunogenes, we constructed a recombinant canine herpesvirus (CHV) expressing glycoprotein (G protein) of rabies virus (RV). The gene of G protein was inserted within the thymidine kinase gene of CHV YP11mu strain under the control of the human cytomegalovirus immediate early promoter. The G protein expressed by the recombinant CHV was processed and transported to the cell surface as in RV infected cells, and showed the same biological activities such as low pH dependent cell fusion and hemadsorption. The antigenic authenticity of the recombinant G protein was confirmed by a panel of monoclonal antibodies specific for G protein. Dogs inoculated intransally with the recombinant CHV produced higher titres of virus neutralizing antibodies against RV than those inoculated with a commercial, inactivated rabies vaccine. These results suggest that the CHV recombinant expressing G protein can be used as a vaccine to control canine rabies and that CHV may be useful as a vector to develop live recombinant against other infectious diseases in dogs.

Animals↗

PubMedDate not supplied

Blood platelets in severely injured burned patients.

Unbelievable decrease of blood-platelet in the severely burned patients during the treatment of skingrafting caused two patients to unexpected death. From the records of changes of platelet number, a certain 'platelet curve' was made. By observing the curve, our treatments of skingrafting were carried out during the stable period and from then on we had no death cases.

Adult↗

PubMedDate not supplied

Electron microscopic study of the cytotoxicity of cadmium and mercury in vitro.

The cells treated with cadmium chloride showed severe changes: ribosomes disappeared, mitochondria showed various degrees of destruction, and the endoplasmic reticulum had a swollen and beadlike appearance. In cells treated with mercuric chloride, ribosomes increased in their density and rosette-like polysomes were predominantly observed. The effects of these two metallic ions were discussed.

Animals↗

PubMedDate not supplied

Production of monodispersed capsules.

A new prehardening process has been demonstrated by passing falling drops through a fine mist of hardening solution, in which drops were generated as monodispersed and concentric two-phase particles. A mixture of vegetable oil and vitamin E has been encapsulated using calcium alginate for rapid hardening and hydroxy propyl methyl cellulose acetate succinate for slow hardening. Both hardening agents produced satisfactory stable encapsulation.

Alginates↗

PubMedDate not supplied

Morphologic studies on the biologic seal of titanium dental implants. Report I. In vitro study on the epithelialization mechanism around the dental implant.

To propose a mechanism for apical epithelialization at the implant-tissue interface, cell contact to titanium surfaces and adhesive strength of epithelial-like (HGE) and fibroblastic (HGF) cells derived from human gingiva were investigated under three different media conditions containing plaque extracts: nonfiltered, 5-micron pore filtered, and 0.22-micron pore filtered. The plaque extracts had a greater effect in decreasing the growth rate of the HGF than of the HGE. Similarly, the HGE exhibited greater adhesive strength than the HGF. These differences in the cells' resistance to plaque extracts were also observed using light and electron microscopy. Evidence from this study suggests that the difference in growth, contact, and adhesive strength of the HGE and HGF cells to titanium surfaces may promote apical epithelialization under the pathologic condition.

Adult↗

PubMedDate not supplied

Morphologic studies on the biologic seal of titanium dental implants. Report II. In vivo study on the defending mechanism of epithelial adhesions/attachment against invasive factors.

Clinical measurements on gingival indices and morphologic observations were performed in this study to verify the defending mechanism of gingival soft tissue against foreign invasions from the perspective of epithelial adhesion/attachment to implant surfaces in the monkey mandible. The following zones were observed using scanning electron microscopy: (1) plaque zone, suggesting susceptibility of the gingival tissue to bacterial invasion; (2) nude zone, demonstrating indirect adhesion of epithelial cells to the implant surface through the mucous layer and preventing bacterial invasion; and (3) epithelial cell attached zone, having greater bond strength of epithelial cells at the cell-implant interface as compared to cell-cell bonding within the epithelial cell layer. This study suggested that epithelial cell attachment/adhesion may play a dominant role in retaining the successful condition of a dental implant.

Animals↗