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Biomedical subjects

T Kuwabara

Publications and source records attributed to T Kuwabara.

At least 199 records · Page 11Linked to original sources
PubMed1987

Uveitis induced in primates by IRBP: humoral and cellular immune responses.

In a previous publication, we have reported that immunization with bovine interphotoreceptor retinoid-binding protein (IRBP) produces severe uveitis in monkeys. The present study further examined the uveitogenicity of IRBP and analysed the immune responses in the immunized monkeys. Uveitis developed in monkeys immunized with bovine IRBP at doses as low as 10 micrograms Kg-1 body wt. In contrast, no disease was detected in monkeys immunized with monkey IRBP at the total dose of 100 micrograms Kg-1. Serum antibodies were measured in the immunized monkeys by the enzyme-linked immunosorbent assay, while cellular immunity was determined by skin hypersensitivity and the lymphocyte mitotic reaction in culture. No humoral or cellular immune responses were detected in monkeys immunized with monkey IRBP. Monkeys immunized with bovine IRBP produced antibodies which cross-reacted well with monkey IRBP. On the other hand, these monkeys did not react with monkey IRBP by skin hypersensitivity and their lymphocytes responded in culture to this protein only when tested by a highly sensitive procedure. In contrast, significant responses of the same cells to bovine IRBP were obtained at all tested conditions. These data are interpreted to suggest that the pathogenic cellular immune responses in vivo detect cross-reactivity with this autologous ocular antigen more efficiently than most conventional laboratory tests.

Animals↗
PubMed1987

Nucleotide sequence of the gene from the cyanobacterium Anacystis nidulans R2 encoding the Mn-stabilizing protein involved in photosystem II water oxidation.

The gene for the Mn-stabilizing protein (MSP; the so-called extrinsic 33-kDa protein) that is involved in photosystem II water oxidation was cloned and sequenced from the genome of the cyanobacterium Anacystis nidulans R2. The gene (here designated woxA) was shown to be present in a single copy. The deduced amino acid sequence indicated that the translation product consisted of 277 amino acid residues with a Mr of 29,306. The comparison of the sequence with that of mature MSP from spinach chloroplasts suggested that the translation product is a precursor whose amino-terminal 28 amino acid residues represent the signal peptide for the protein to cross the thylakoid membrane into the lumen. The length of the putative signal peptide was less than half that of the transit peptide for thylakoid-lumenal proteins of higher plants, whereas the structural profile of the putative signal peptide was similar to that of the carboxyl-terminal portion of the higher plant transit peptides. The amino acid sequence of the mature A. nidulans R2 MSP showed rather low homology (48-49%) to higher plant MSPs, but the conserved amino acid residues appeared to be clustered. Five clusters were tentatively assigned, in which the homology values were in a range of 66-70%. Domains essential for the functioning of MSP are expected to be situated in these clusters. It is of note that the two cysteine residues in MSP were conserved, and the disulfide linkage between them may play an important role in maintaining the tertiary structure of MSP.

Amino Acid Sequence↗
PubMed1987

Defects in lens fiber differentiation are linked to c-mos overexpression in transgenic mice.

We describe three strains of transgenic mice derived by embryo microinjection of DNA consisting of a long terminal repeat (LTR) of Moloney murine sarcoma virus (Mo-MSV) linked to the murine c-mos coding sequences. Southern analysis of the genomic DNA of these strains suggested that in each case the transgene had integrated at a different chromosomal location. The strains were characterized by dominant changes in secondary lens fiber differentiation. Shortly after birth, insufficient elongation of differentiating lens fibers and lack of basement membrane secretion resulted in breakdown of the posterior lens capsule. This, in turn led to posterior protrusion and swelling of lens tissue. In the course of the first 3 weeks after birth, globular lens cells began to fill the entire anterior and posterior chambers of the eye. Concomitantly, there was massive overexpression of c-mos RNA in the lens. Whereas this construct has high transforming activity when transfected into NIH-3T3 cells, no hyperplasia or neoplasia have been observed in the affected lenses. Increased expression of c-mos RNA was not confined to the lens of the eye but has been detected in any of several tissues tested.

Animals↗
PubMed1987

IRBP from bovine retina is poorly uveitogenic in guinea pigs and is identical to A-antigen.

Retinal interphotoreceptor retinoid-binding protein (IRBP) is a potent uveitogen in Lewis rats, producing experimental autoimmune uveitis (EAU) reproducibly at doses lower than those of S-antigen (S-Ag). In contrast, IRBP was found to be poorly uveitogenic in three strains of guinea pigs, inducing only minor changes in a small proportion of these animals. On the other hand, S-Ag was found to induce EAU in the majority of immunized guinea pigs, with changes more severe than those induced by IRBP. Unlike the difference in their uveitogenicity, IRBP and S-Ag induced similar levels of specific immune responses in the immunized guinea pigs. The poor uveitogenicity of IRBP in guinea pigs resembles that of A-antigen (A-Ag). The two proteins are also similar in other features and were found in this study to be antigenically identical. It is proposed that IRBP and A-Ag are one and the same protein.

Animals↗
PubMed1987

Quantitative measurements of retinal edema by specific gravity determinations.

We have quantified retinal edema in rat by specific gravity measurements in vitro. Specific gravity corresponds to tissue water content, which is increased in retinal edema. The gravimetric analysis of retinal edema corresponds well with light and transmission electron microscopy and radiolabelled albumen studies. Specific gravity measurements are the standard method to measure brain edema and are also applicable to the measurement of retinal edema.

Animals↗
PubMed1986

In vitro synthesis and assembly of photosystem II proteins of spinach chloroplasts.

The synthesis and assembly of photosystem II (PS II) proteins of spinach chloroplasts were investigated in three different in vitro systems, i.e., protein synthesis in isolated chloroplasts (in organello translation), read-out translation of thylakoid-bound ribosomes, and transport of translation products from spinach leaf polyadenylated RNA into isolated chloroplasts. Polyacrylamide gel electrophoresis of labeled thylakoid polypeptides in the presence of sodium dodecyl sulfate revealed that the first two systems were capable of synthesizing the reaction center proteins of PS II (47 and 43 kDa), the herbicide-binding protein, and cytochrome b559. The reaction center proteins synthesized in organello were shown to bind chlorophyll and to assemble properly into the PS II core complex. One of the reaction center proteins translated by the thylakoid-bound ribosomes (47 kDa) was also found to be integrated in situ into the complex but was lacking bound chlorophyll. Incorporation of radioactivity into the three extrinsic proteins of the oxygen-evolution system (33, 24, and 18 kDa) was detected only when intact chloroplasts were incubated with the translation products from polyadenylated RNA, showing that these proteins are coded for by nuclear DNA. The occurrence of a precursor polypeptide 6 kDa larger than the 33-kDa protein was immunochemically detected in the translation products.

Biological Transport↗
PubMed1986

T cell lines mediating experimental autoimmune uveoretinitis (EAU) in the rat.

Long-term S-antigen (S-Ag)-specific T lymphocyte lines were derived from the lymph nodes of immunized Lewis rats that had been pretreated with low-dose cyclophosphamide. The protocol consisted of functional selection by alternating cycles of stimulation with S-Ag presented on syngeneic accessory cells and proliferation in IL 2-containing spleen-conditioned medium, coupled with early phenotypic selection for cells bearing the helper/inducer membrane marker (W3/25), by panning on antibody-coated plastic dishes. This protocol consistently resulted in the rapid generation of in vivo functional cell lines capable of mediating experimental autoimmune uveoretinitis (EAU) when transferred into naive rats at 5 to 10 X 10(6) cells/rat systemically or 1 to 2 X 10(6) cells/rat intravitreally. The disease appeared within 6 to 8 days, usually with minimal anterior chamber involvement, and was often unilateral. Pathologic changes resembled those seen in EAU induced by active immunization. The disease could be transferred without concomitant formation of serum antibodies. The uveitogenic line cells were negative for Ia antigen and positive for the W3/25 membrane marker, which appeared to be stable in long-term culture. They proliferated vigorously in vitro and produced IL 2 in response to S-Ag or Con A, but not to unrelated antigens. The establishment of uveitogenic T helper lymphocyte lines will permit the analysis of the cellular mechanisms involved in EAU in a more defined system than has been available.

Animals↗
PubMed1986

Accessory cells in vessels of the paranatal human retina.

Retinas of the paranatal period contain two types of cell clusters that are generally believed to play a role in the developing vasculature. The more posterior cluster consists of angioblastic cells, which undergo lumenization to form the definitive vessels. Anterior to this cluster and separated from it by a distinct boundary are clusters of spindle cells extending a variable distance toward the periphery. These clusters of spindle cells maintain a fixed position relative to the angioblastic masses, without any admixture of the two. The precise function of the spindle cells in the vascularizing process has been a subject of controversy. We found evidence to identify them as glia and to suggest that their role is to provide an energy source for the developing retina as the hyaloid vessels recede and until the retinal vessels take over this function. It further appears that congenital failure of the vessels to develop may result in a persistence of these spindle cells, in the form of hyperplastic glia in the inner layers of the retina. Our study included normal eyes from full-term and premature infants and eyes from patients with retinopathy of prematurity (oxygen-related retinopathy), anencephaly, and other congenital anomalies.

Anencephaly↗
PubMed1986

Uveitis induced in primates by interphotoreceptor retinoid-binding protein.

Interphotoreceptor retinoid-binding protein was found to be highly uveitogenic in primates. All six monkeys immunized with bovine interphotoreceptor retinoid-binding protein developed ocular inflammation. The main clinical changes were sheathing of retinal vessels and deep well-circumscribed yellow-white lesions. Histologic changes in the retina included shortening of the outer segments and foci of inflammation, which extended through all retinal layers. Particularly profound were the choroidal changes, such as severe inflammatory infiltration, which often formed focal granulomas with epithelioid and giant cells. Some granulomas had the structure of Dalen-Fuchs nodules. These structures and other histologic changes in the monkeys closely resemble those in uveitic conditions in humans, such as sympathetic ophthalmia or Vogt-Koyanagi-Harada syndrome. These findings show that antigen that localizes specifically in the retina may initiate an immunopathogenic process affecting mainly the choroid.

Animals↗
PubMed1986

31P-NMR studies on an animal model of human defective muscle glycolysis.

Sequential metabolic changes in leg muscles of a model of defective muscle glycolysis that was produced by intraaortic injection of sodium iodoacetate were observed by in vivo 31P-NMR spectroscopy with a surface coil. Spectra obtained from iodoacetate-treated muscles presenting exercise-induced cramp showed decreased levels of phosphocreatinine (PCr) and adenosine triphosphate (ATP) and an accumulation of sugar phosphate. The chemical shift of inorganic phosphate (Pi) resonance, which reflects the intracellular pH of the contracted muscles, showed a milder shift to the acidic condition than those of controls. In vivo 31P-NMR study showed dynamic information on the muscle energetics under defective glycolytic conditions.

Animals↗
PubMed1986

The effects of pertussis toxin on the induction and transfer of experimental autoimmune uveoretinitis.

Experimental autoimmune uveoretinitis (EAU), an intraocular inflammatory disease, is induced in experimental animals by immunization with a retinal specific antigen, S-antigen (S-Ag), emulsified in complete Freund's adjuvant (CFA). The induction of EAU is enhanced by treating S-Ag-immunized animals with Bordetella pertussis. This study examined the effects of a purified component of B. pertussis, pertussis toxin (Ptx), on EAU induction as well as the mode of action of this toxin. Treatment of Lewis rats with Ptx concurrent with S-Ag and CFA enhanced EAU induction as shown by an earlier onset of disease, increased severity of ocular changes, and the reduction of the threshold amount of S-Ag needed for EAU induction. Treatment with Ptx selectively enhanced delayed-type hypersensitivity responses to S-Ag but did not affect specific antibody production. The mode of action of Ptx was analyzed by using the adoptive transfer of EAU by sensitized lymphocytes. Ptx treatment of donor rats enhanced the capacity of lymphocytes to transfer EAU. However, Ptx treatment of recipient rats on the day of cell transfer resulted in a delay in the onset of disease. These results indicate that Ptx enhances the immunopathogenic processes of EAU by enhancing lymphocyte activation and/or increasing their pathogenic activities.

Animals↗
PubMed1986

Sympathetic ophthalmia. Immunopathological findings.

Ocular tissue from six patients with a clinical diagnosis of sympathetic ophthalmia (SO) was examined using immunohistochemical techniques. All patients presented with a history of bilateral panuveitis after penetrating ocular injury or multiple intraocular surgeries and clinical features of SO. In four cases, classic histopathological features of SO were observed, including granulomatous uveal tract infiltration and subretinal pigment epithelium (RPE) collections of inflammatory cells (Dalen-Fuchs nodules). Bone marrow derived monocytes were the major cellular components in these granulomas. In two cases, histopathology failed to demonstrate typical Dalen-Fuchs nodules or granulomas in the choroid. However, the choroidal infiltrates were composed primarily of T-helper and B lymphocytes, without macrophages or epithelioid cells. The eyes examined in this report indicate that a varied spectrum of immunopathological and histopathological findings may occur in clinically diagnosed SO.

Adult↗
PubMed1986

Purification of membrane polypeptides of rat liver peroxisomes.

Peroxisomes were obtained by sucrose density gradient centrifugation from the livers of di(2-ethylhexyl)phthalate-fed rats, and the membranes were prepared by carbonate extraction (Fujiki, Y., Fowler, S., Shio, H., Hubbard, A.L., & Lazarow, P.B. (1982) J. Cell Biol. 93, 103-110). The integrated membrane polypeptides were solubilized with sodium dodecyl sulfate, and purified by repeated polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Separation of 70 and 68 kDa polypeptides was not attempted in the present study because of their close migration in polyacrylamide gel electrophoresis. Other polypeptides with apparent molecular masses of 41, 27, 26, and 22 kDa were purified to near homogeneity. Antibodies were raised against these purified preparations. The 68 kDa polypeptide is suggested to be produced by the proteolytic modification of 70 kDa polypeptide, since the former increased concomitantly with decrease of the latter when the liver homogenate was incubated, and this change was prevented in the presence of leupeptin during the incubation. The 41 kDa polypeptide was a minor component. The 70 and 68 kDa polypeptides and 41 kDa polypeptide and their antibodies were cross-reactive, but the relation of these polypeptides was not clear. The 27 and 26 kDa polypeptides seemed to be another species of membrane polypeptides, although the relationship of these two polypeptides remains to be clarified. The 22 kDa polypeptide is not related to other membrane polypeptides. The results of immunoblot analysis of subcellular fractions of the liver and an electron microscopic immunocytochemical study to locate the antigenic sites with protein A-gold complex suggest that all of these polypeptides are localized on peroxisomal membranes. On proliferation of rat liver peroxisomes by administration of di(2-ethylhexyl)phthalate, a peroxisome proliferator, all of these polypeptides were markedly increased.

Animals↗
PubMed1986

Orbitocraniobasal approach for anterior communicating artery aneurysms.

We describe an orbitofrontotemporobasal craniotomy technique that allows excellent access to anterior communicating artery aneurysms. This orbitocraniobasal approach is particularly useful for the surgical treatment of ruptured aneurysms in the acute stage of subarachnoid hemorrhage, when retraction of the brain needs to be kept to a minimum. With this approach, retraction of the orbital contents decreases the amount of retraction of the brain to such an extent that a brain spatula is not necessary for access to the anterior communicating artery complex. The procedure is described, as is a modification of the approach for removal of large tumors on the skull base.

Cerebral Arteries↗