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Biomedical subjects

T Komuro

Publications and source records attributed to T Komuro.

At least 73 records · Page 4Linked to original sources
PubMed1991

In-vitro dissolution properties of indomethacin extended-release capsules.

In-vitro dissolution properties of indomethacin extended-release capsules, from samples available on the Japanese market, have been investigated using a continuous flow, column-type dissolution apparatus and the results compared with those obtained by the paddle and the rotating basket methods. A plot of the percent of drug dissolved against the square root of time gave a straight line with the flow-through method but not with the paddle or the rotating basket methods. The results suggest an advantage of the flow-through method over the other two methods when extended-release products are tested by in-vitro dissolution.

Chemistry, Pharmaceutical↗
PubMed1990

Re-evaluation of fibroblasts and fibroblast-like cells.

Scanning electron microscopic observations of connective tissue cells show a new aspect of the nature of fibroblasts, and the subsequent broad survey of references makes clear that fibroblasts of many tissues have various features which are regarded as atypical of fibroblasts, and at the same time that various connective tissue cells in different organs have features typical of fibroblasts. Both morphological and functional features of fibroblasts are more or less common to those of fibroblast-like cells, and differences among these cells are quantitative rather than qualitative. Therefore, it is almost impossible to set clear-cut criteria for distinguishing genuine fibroblasts from a large population of fibroblast-like cells. The majority of cells sharing features of fibroblasts, if not all, seem to belong to the same population of cells. They are probably adapted to special functional needs in their own micro-environment that are peculiar to local or pathological or experimental conditions. It is proposed to categorize these cells into subtypes depending on their main functions: 1, fibrogenesis; 2, tissue skeleton or barrier; 3, intercellular communication system; 4, gentle contractile machinery; 5, endocrine activity; and 6, vitamin A-storing. Re-evaluation of fibroblasts and fibroblast-like cells is required to facilitate their better understanding.

Animals↗
PubMed1990

Synergistic T-T cell interaction present in alloreactivity: determination of 'MLR helper' T cell subsets.

CD4 and CD8 T cell subsets involved in primary allo-MLR responses were re-evaluated in the present study. The slope analysis of B6 allo-MLR responses to MHC class I-disparate bm1 and class II-disparate bm12 revealed the presence of a T-T cell interaction between CD4 and CD8 T cell subsets. The allo-MLR response of B6 CD4 T cells to bm12 was completely blocked by anti-L3T4, indicating that the function of CD4 T cells is required for allo-MLR responses to bm12. It was further demonstrated that the function of CD8 T cells in class II-disparate allo-MLR is to augment the proliferative response of CD4 T cells. On the other hand, CD8 T cells primarily responded to class I-disparate allo-MLR, and CD4 T cells function to augment the proliferative response of CD8 T cells. It was further indicated that CD4 and CD8 T cells recognize both class I and class II MHC. The CD4 T cell recognition of allo-class I and CD8 T cell recognition of allo-class II induces insufficient signals for proliferation of these T cells. Thus, the class I-reactive CD4 and class II-reactive CD8 T cell subsets function as helper cells ('MLR helper' T cells) for proliferating T cells in MLR responses.

Animals↗
PubMed1990

Analysis of age-related degeneracy of T-cell repertoire: localized functional failure in CD8+ T cells.

The repertoire and frequency of alloreactive T cells in aged mice were examined by limiting dilution analysis of the mixed-lymphocyte reaction (MLR). Mice were aged in specific pathogen-free conditions up to 31 months, and MLR of their spleen cells under limiting dilution conditions was examined at various stages of ageing. The frequency of alloreactive T cells was found to decrease in mice more than 14 months of age, and the value reached about 1/3 of that of young mice of 2 months of age. The slope analysis of cell dose-response curves of MLR indicated the existence of two interacting T-cell populations, i.e. CD4+ and CD8+, cooperation between which is required for the full manifestation of MLR in limiting dilution conditions. The decrease in the alloreactivity of aged spleen cells was ascribed to the selective functional loss of the CD8+ population, because the CD4+ but not the CD8+ T-cell fraction from aged mice could restore the limiting factor in MLR. The decrease in the cooperative activity of CD8+ T cells in allo-MLR starts much earlier than the decrease in the number of CD8+ T cells in the spleen.

Aging↗
PubMed1990

Age-related degeneracy of T cell repertoire: influence of the aged environment on T cell allorecognition.

The present study was undertaken to understand the mechanism of alteration of the alloreactivity of T cells in aged mice. The experiment utilized bone marrow chimeras revealed that the age-associated changes in alloreactivity are not primarily determined by the bone marrow stem cells but determined by the environment where stem cells differentiate into mature T cells. The limiting dilution analysis and microfluorometry analysis indicated that the changes lie in both frequency of alloreactive T cells and the expression of T cell antigen receptor. Such quantitative and qualitative changes seems to be the causes for declined alloreactivity of T cells in aged mice.

Age Factors↗
PubMed1990

[Studies on the degradation of chitosan films by lysozyme and release of loaded chemicals].

Chitosan films with or without chemicals of interest were prepared and degradation properties of chitosan films of themselves by lysozyme and releases of the loaded chemicals from the films were investigated. Enzymatic degradation rate of the films was dependent on the degree of deacetylation of chitosan used and decreased with an increase in its deacetylation. The acidic conditions accelerated the degradation compared to the neutral pH. Most of the water-soluble chemicals used in the present experiments except Coomassie Brilliant Blue with a strong acidic group and pullulan with a high molecular weight (5.8 x 10(4)-38.0 x 10(4], were rapidly released from the films within 1 h. The two chemicals described above were released only in the presence of lysozyme, and their release rates were controlled by the degradation rate of the films.

Biotransformation↗
PubMed1990

Three-dimensional structure of the rat intestinal wall (mucosa and submucosa).

The three-dimensional organization of the mucosa and submucosa of the rat intestine was analysed by scanning electron microscopy (SEM) aided by micro-dissection methods. New functional aspects raised by the SEM observations were examined by transmission electron microscopy (TEM). Morphogenesis of the intestinal villi was also illustrated three dimensionally. Removal of the epithelium by osmic acid maceration revealed the presence of many round fenestrations averaging 3 microns in diameter over the villous basal lamina. TEM confirmed that they were not artifacts but represented passages or tracks of cells of the immune system such as lymphocytes, eosinophils and macrophages. Penetration of the epithelial processes into the lamina propria was also observed. Close contacts between these free cells and the epithelial cells suggest an intercellular communication between these different cell types. The basal lamina is thus appears as a structure that allows dynamic interaction between the epithelial layer and the lamina propria, though it is generally regarded as a rigid structure acting as a barrier. Beneath the basal lamina, a cellular reticulum of fibroblast-like cells overlies the capillary network in the villi. These cells are characterized by bundles of actin filaments and contact with each other by gap junctions. This cellular reticulum probably influences the absorption of nutrients from the villi by its contractile ability in addition to its supportive role. A similar cellular network occurs beneath the epithelium of the intestinal glands. These cells may also mechanically support the glandular organization, maintaining the delicate microvascular bed. The submucosa is considered the skeleton of the intestine. SEM reveals the main framework of the submucosa is as being composed of two sets of collagen fibers running diagonally around the intestinal wall, one set in a clockwise direction, the other, counterclockwise. These fibers--in different arrays--interweave to form a lattice sheet, which presumably provides the tissue with a high resistance to mechanical forces, particularly in respect to radial forces. The diagonal orientation of the collagen fibers is essential for the flexibility of the submucosa in allowing deformation of the intestinal wall during peristalsis. Despite the nonelastic nature of the collagen fibers, the submucosa can adapt to the various shapes of the intestinal lumen by simply changing the angles formed by these fibers. Structures of the villous microcirculation, the muscularis mucosae and of the submucous plexus are also discussed.

Animals↗
PubMed1990

[Usage of chitosan as a pharmaceutical material effectiveness as an additional additives of sodium alginate].

Application of chitosan, a deacetylated compound of chitin obtained from shells of shrimps, was investigated with reference to the pharmaceutical excipient for directly compressed tablets. Several drugs were chosen as model compounds and their in vitro dissolution tests were carried out according to the JP XI dissolution test. When chitosan was used alone as an excipient, immediate-release tablets were obtained, as already reported. But when more than 5% of sodium alginate, 1000 cps, was added as excipient, tablets showed an extended-release property under the present experimental conditions.

Adjuvants, Pharmaceutic↗
PubMed1990

[Liver regeneration and immune system--morphological and cytochemical studies of activated spleen cells during the liver regeneration after partial hepatectomy].

Morphological and cytochemical changes were investigated in spleen cells after 70% hepatectomy in mice. During liver regeneration after the hepatectomy, the spleen weight gradually rose to a peak at 6 day. In the spleen, the number of POD-positive myelocytic cells and NCAE-positive granulocytic cells also reached a peak 4 days after the operation and then decreased. On the other hand, ANBE-positive monocytic cells gradually increased up to 9 day and didn't decrease for this period. On day 9 of the culture, the boundary between the red and the white pulps of the spleen became unclear. In this spleen, the clusters of blast cells were sporadically observed. Splenic T cells cocultured with nonparenchymal adherent normal liver cell or nonparenchymal adherent normal liver cell supernatant developed into granulocyte colonies in earlier periods and monocyte colonies in later periods. These findings suggest that the factors released from liver cells may regulate strictly spleen cell activation. Blast cell formation in the culture with nonparenchymal adherent normal liver cell supernatant was amplified by anti interferon (alpha + beta) antibody. These facts indicate that the functional network of cytokines is formed by the interaction of various cytokines (IL-1, IL-6, CSF, IFN, etc.) in nonparenchymal adherent normal liver cell supernatant.

Animals↗
PubMed1989

Comparison of R- and S-form lipopolysaccharides fractionated from Escherichia coli UKT-B lipopolysaccharide in pyrogen and Limulus tests.

Different LPS was shown to have a relatively different proportion of O-specific chain-less (R-form) LPS by polyacrylamide gel electrophoresis (PAGE) with sodium deoxycholate (DOC). By using DOC-PAGE, S-form LPS having O-chain with approximately 11 repeating units on average (S-Fr) and O-chain-less LPS (R-Fr) were separated from Escherichia coli UKT-B S-form LPS. Significantly stronger pyrogenicity was observed in R-Fr than in S-Fr when measured on the weight basis. Similar result was observed in Limulus test. Comparing biological activities of different S-form LPS, attention should be given to the amounts of co-existing R-form LPS.

Deoxycholic Acid↗
PubMed1989

Three-dimensional observation of the fibroblast-like cells associated with the rat myenteric plexus, with special reference to the interstitial cells of Cajal.

An extensive cellular network becomes visible over the myenteric plexus of the rat after removal of the overlying tissues under the scanning electron microscope. The cells are mainly stellate and have many slender processes via which they interconnect. They form a three-dimensional network and are closely associated with the ganglia and nerve bundles, and also extend over the smooth muscle cells. They are considered to correspond to the interstitial cells of Cajal because of their peculiar arrangement and their topography. Transmission electron-microscopic evidence demonstrates that the majority of those cells have features of fibroblasts. Gap junctions and intermediate junctions are observed between these fibroblast-like cells, and also between them and smooth muscle cells. Examination of serial thin sections reveals that single fibroblast-like interstitial cells connect to both circular and longitudinal muscle cells via gap junctions. It is suggested that the network of interstitial cells conducts electrical signals.

Animals↗
PubMed1989

Determination of ABO blood groups from saliva and saliva stains by an indirect enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies.

The detection of A, B and H blood group substances (ABH-BGS) in saliva and in saliva stains has been investigated quantitatively by an indirect ELISA using a horseradish peroxidase conjugate in combination with the use of monoclonal antibodies. Through this method, the reaction specificity to BGS in the saliva was very high and its detection sensitivity was found to be approximately 1,000 times greater than has been achieved in a hemagglutination-inhibition test. The monoclonal anti-A and anti-B reagents reacting with both secretor and non-secretor saliva in a hemagglutination-inhibition test and in this ELISA method were selected from among commercial monoclonal antibodies. However, no monoclonal anti-H reagent was found to react with non-secretor saliva. The BGS level was determined by the use of calibration curves of A, B and H standard BGS from human gastric mucosa and was expressed in units, based on the inhibition titer of the standard BGS. In 230 saliva samples, ABH-BGS were detectable, except for H BGS in non-secretor saliva. The BGS levels in saliva stains experimentally prepared were found to be approximately proportional to the levels in the original saliva. As for actual and aged stains, it was possible to detect BGS in most cigarette butts and in aged stains, however, such detection proved impossible in saliva samples from postage stamp.

ABO Blood-Group System↗
PubMed1989

[Lysozyme Reference Standard (Control 871) of the National Institute of Hygienic Sciences].

A candidate for the Lysozyme Reference Standard (Control 871) of the National Institute of Hygienic Sciences was prepared. Purity of the standard material examined electrophoretically was more than 99.5%. Lysozyme potency of the standard material was assayed turbidimetrically using dry-cells of Micrococcus luteus as a substrate and compared with that of the Lysozyme Reference Standard (Control 865). Potency of the standard material was in satisfactory agreement with that of the standard and was defined as 1 mg [potency] per mg.

Amino Acids↗
PubMed1989

[Collaborative study of Japanese Pharmacopoeia Heparin Sodium Reference Standard (Control 871)].

Heparin Sodium Reference Standard for Japanese Pharmacopoeia (JP) is replaced with new material derived from porcine mucosa. The material was dissolved in water, distributed to vials and freeze-dried. The anticoagulant activity of the freeze-dried product was determined in collaboration with four laboratories employing JP method. The weighted mean potency of 101 assays was 1515 international units per vial, and this value was adopted for the potency of new JP Heparin Sodium Reference Standard (Control 871). By the antiheparin test of protamine sulfate, 0.712 mg of the new standard was neutralized by 1 mg of protamine sulfate. Molecular weight distribution of this standard was also measured by means of gel permeation chromatography and compared with those of the former reference standard and bovine heparin.

Anticoagulants↗