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Biomedical subjects

S Shimada

Publications and source records attributed to S Shimada.

At least 343 records · Page 19Linked to original sources
PubMed1988

Metabolism of drugs in the eye. Drug-reducing activity of preparations from bovine ciliary body.

Drug-metabolizing activities, especially the reductase activities towards N-oxide, hydroxamic acid, sulfoxide and nitro compounds were comparatively examined with bovine ciliary body. As described previously, the cytosol from the ocular tissue exhibits the nicotinamide N-oxide reductase activity when supplemented with 2-hydroxypyrimidine, an electron donor of aldehyde oxidase. When the cytosol was fractionated with ammonium sulfate, followed by assays of aldehyde oxidase and nicotinamide N-oxide reductase activities in each fraction, the distribution of aldehyde oxidase activity in the resultant ammonium sulfate fractions was nearly parallel to that of nicotinamide N-oxide reductase activity. Furthermore, reductase activities towards drugs such as sulfoxide, hydroxamic acid and nitro compounds were observed with the cytosol in the presence of 2-hydroxypyrimidine or N1-methylnicotinamide. In general, these reductase activities of the fraction were markedly inhibited by menadione, an inhibitor of aldehyde oxidase. These results suggest that aldehyde oxidase present in ciliary body plays an important role in the reduction of a variety of xenobiotics in mammalian eyes. However, in the case of imipramine N-oxide, its reduction in the ocular tissue appears to be more readily catalyzed by a menadione-linked enzyme different from aldehyde oxidase.

Aldehyde Oxidoreductases↗
PubMed1988

The skin as an immunologic organ.

The epidermis is a heterogeneous tissue comprised of cells that may play a role in various types of immunologic responses. This review focuses on the importance of epidermal Langerhans' cells in antigen presenting and accessory cell functions, on the role of la-positive keratinocytes in generating certain types of immune responses, on the role of normal keratinocytes in the liberation of cytokines, on the identification of murine Thy-1-bearing dendritic epidermal cells, and on the modulation of epidermal immune functions by various physical and chemical agents.

Adrenal Cortex Hormones↗
PubMed1988

Bone marrow transplantation in miniature swine. III. Graft-versus-host disease and the effect of T cell depletion of marrow.

Graft-versus-host disease (GVHD) has been evaluated in partially inbred miniature swine in order to study this complication of allogeneic bone marrow transplantation (BMT) in a major histocompatibility complex (MHC) genetically defined large animal model. Bone marrow from MHC homozygous ("parental") swine was injected into irradiated (900 rads total-body irradiation) MHC heterozygous ("F1") swine that shared one haplotype with the donor. All 18 animals successfully engrafted with donor bone marrow, and 17 of these developed skin rash of varying intensity depending on the extent of T cell depletion of infused marrow. Of 18 animals, 8 received undepleted bone marrow from exsanguinated donors and 2 also received additional peripheral blood lymphocytes (PBL) as a source of mature T cells. All 8 showed a moderate-to-severe rash, and the 2 pigs that received additional donor PBL developed the most severe rash. The cutaneous eruption seen in this model clinically, histologically, and immunologically resembled human GVHD. Two protocols of T cell depletion of donor bone marrow by antiporcine T cell monoclonal antibodies plus complement were tested for their effect on development of GVHD. The combination of two monoclonal antibodies, 74-12-4 (PT4) and 76-2-11 (PT8), had a marginal effect on the subsequent development of cutaneous manifestations of GVHD. However, treatment of the donor marrow by a combination of three monoclonal antibodies--PT4, PT8, and MSA4 (PT11)--effectively decreased the severity of the GVHD skin rash. These results indicate that (1) the GVHD associated with allogeneic bone marrow transplantation in swine is dependent on T cells in the marrow; (2) effective T cell depletion of donor marrow by monoclonal antibodies and complement does not prevent engraftment; and (3) this swine GVHD model, which allows study with F1 and homozygous parental combinations in an MHC genetically defined large animal, is particularly useful for the understanding of GVHD pathogenesis, prevention, and treatment.

Animals↗
PubMed1987

Coexistence of substance P- and enkephalin-like peptides in single neurons of the rat hypothalamus.

The distribution of substance P- and enkephalin-like immunoreactivity in single cells were examined by the double immunofluorescence method. Substance P- and leucine-enkephalin-like compounds coexisted within individual neurons of some hypothalamic areas such as the medial preoptic area, anterior hypothalamic area, perifornical area, lateral hypothalamic area, premammillary nuclei and posterior hypothalamic nucleus, although they did not coexist in the majority of immunoreactive cells.

Animals↗
PubMed1987

Enhanced antigen-presenting capacity of cultured Langerhans' cells is associated with markedly increased expression of Ia antigen.

Recent studies indicate that when epidermal Langerhans' cells (LC) are cultured for 2 to 3 days they, in comparison to freshly prepared LC, exhibit markedly enhanced ability to stimulate T cell proliferative responses in oxidative mitogenesis and in the mixed epidermal-leukocyte reaction. In this study, we determined whether cultured LC enhance antigen-specific T cell responses, and whether such enhanced stimulatory capacity correlates with the level of Ia antigen expressed on LC. We used C3H/He (Iak) epidermal cells as stimulators and, as responder cells, both the trinitrophenyl-specific clones D8 and SE4, which were assayed for [3H]dThd incorporation, and the pigeon cytochrome c specific hybridoma 2C2, which was assayed for interleukin 2 production. Cultured LC induced 10 to 100 times greater proliferation or interleukin 2 production by responder cells than did freshly prepared LC. The intensity of I-Ak and I-Ek, expressed on cultured LC as assessed by immunofluorescence and flow cytometry, was found to be 10 to 36 times greater on a per cell basis than that on freshly prepared LC. Depletion of LC from fresh epidermal cell suspensions by anti-Iak and complement or treatment with 50 mJ/cm2 medium range ultraviolet light or cycloheximide before culture abrogated both the increase in Ia expression and antigen-specific clonal proliferation. The results suggest that when LC are removed from their usual epidermal milieu, they express increased amounts of Ia and become more potent stimulators of T cell responses.

Animals↗
PubMed1987

Transient appearance of calcitonin gene-related peptide-like immunoreactive fibers in the developing cerebellum of the rat.

A plexus of calcitonin gene-related peptide (CGRP)-containing fibers were transiently found in the developing cerebellum of the rat by means of the indirect immunofluorescent method. CGRP-like immunoreactive fibers appeared in the cerebellum by embryonic day 22. Immunoreactive fibers rapidly increased and these made a dense plexus in the Purkinje cell layer by postnatal day 2. However, only a few if any immunoreactive fibers were seen in the Purkinje cell layer or molecular layer of adult rats.

Animals↗
PubMed1987

Neostriatal cholinergic neurons receive direct synaptic inputs from dopaminergic axons.

We used an electron microscopic 'mirror technique' to determine whether cholinergic neurons are in direct synaptic contact with dopaminergic axons in the rat neostriatum. Tyrosine hydroxylase-immunoreactive axons make synaptic contacts with the somata and proximal dendrites of large choline acetyltransferase-immunoreactive striatal neurons which are thought to be interneurons. This provides morphological evidence that nigrostriatal dopaminergic neurons can influence monosynaptically the striatal cholinergic neurons.

Adrenergic Fibers↗
PubMed1987

Antigen reversion of glycogen phosphorylase isoenzyme in carcinoma and proliferative zone of intestinal metaplasia of the human stomach. An immunohistochemical study.

Specific antibodies to three purified glycogen phosphorylase isoenzymes, i.e., brain (or fetal), muscle, and liver types, were used to study the localization of these isoenzymes in carcinoma and the proliferative zone of intestinal metaplasia of the human stomach. Both the malignant cells of well-differentiated adenocarcinoma and the proliferative zone of some intestinal metaplasia of the stomach were stained when the antibrain-type phosphorylase isoenzyme antibody was used, but not when the other two types were used. The results suggest that brain-type phosphorylase in gastric carcinoma could be one example of fetal protein expression in cancer, and that the proliferative zone of some intestinal metaplasia having brain-type phosphorylase may histogenetically relate to well-differentiated adenocarcinoma.

Adenocarcinoma↗
PubMed1987

Production of human--human hybridomas secreting antibody to sheep erythrocytes after in vitro immunization of peripheral blood lymphocytes.

This report describes the formation of human hybridomas after in vitro immunization of peripheral blood lymphocytes (PBL) with an antigen and fusion of the stimulated lymphocytes with a HAT-sensitive human myeloma cell line, RPMI 8226. PBL were stimulated in vitro with sheep erythrocytes (SRBC) plus fresh human serum. PBL of some donors produced anti-SRBC antibody when they were cultured at 2 X 10(6) cells per well in a 24-well plate with the antigen plus fresh human serum for 7 days. Although lymphocytes of some donors were "low-responders" under the above conditions, they responded to SRBC when they were cultured with not only the antigen plus fresh human serum but also with the culture supernatant obtained after phytohemagglutinin (PHA) stimulation of a mixture of PBL from two donors (MLC-PHA sup). The cells sensitized by this procedure were fused with RPMI 8226 cells. Hybrids secreting IgM or IgG anti-SRBC antibodies were obtained. Additionally the ratio of total IgG-producing hybridomas to IgM-producing ones was higher when the MLC-PHA sup was used at the time of the in vitro immunization.

Animals↗
PubMed1987

Glutamate decarboxylase-like immunoreactive neurons in the rat caudate putamen.

GAD-IR neurons were roughly divided into those with medium sized perikarya and large perikarya. The medium-sized GAD-IR neurons accounted for about 85% of the GAD-IR neurons. The medium-sized perikarya were further divided into two, those with a smooth nuclear membrane and those with an indented nucleus. The former were very similar to medium-sized spiny neurons and the latter corresponded to medium-sized aspiny neurons. The GAD-IR large cells that were identified by light microscopy, had nuclear indentations and were divided into two classes based on their ultrastructural features, type 1 large cells received few synaptic inputs and type 2 large cells received many synaptic contacts from non-immunoreactive or immunoreactive boutons. The former resembles Type I large cells and the latter Type II large cells identified recently by Chang and Kitai; the latter are also similar to the second type of projecting neurons identified by Bolam et al.

Animals↗
PubMed1987

Preparation of monoclonal antibodies against a glycolipid asialo GM1.

Five IgM monoclonal antibodies (MAbs), MW-1, MW-2, MW-3, MW-4, and MW-5, against a glycolipid asialo GM1 were prepared from hybridoma clones obtained by the fusion of mouse NS-1 myeloma cells with spleen cells from a mouse immunized with asialo GM1 adsorbed to naked Salmonella. All the MAbs reacted only with asialo GM1 when their reactivities were examined by enzyme-linked immunosorbent assay (ELISA) and thin-layer chromatography (TLC)-immunostaining using structurally related glycolipids. The MAbs showed a complement-dependent lysis of mouse natural killer (NK) cells, but the lytic activities were weaker than that of a rabbit polyclonal anti-asialo GM1 antibody. When they were mixed, the anti-NK activity was increased to a level almost comparable to that of the polyclonal antibody. These results suggest that all the MAbs obtained are specific for asialo GM1 and that they may be different in fine specificity for the glycolipid. Significance of the MAbs in immunological and neurochemical studies is discussed.

Animals↗