Search PubMed⌕ Search

Biomedical subjects

Y Kohno

Publications and source records attributed to Y Kohno.

At least 235 records · Page 13Linked to original sources
PubMed1990

Purification and identification of creatine phosphokinase B as a substrate of protein kinase C in mouse skin in vivo.

We previously described epidermal proteins with molecular weights of 40,000 (p40) and 34,000 (p34) as target proteins of protein kinase C in mouse skin carcinogenesis in vivo. In the present work, p40 was purified from mouse brain by the use of 32P-labeled p40 of BALB/MK-2 cells as a tracer. Following four lines of evidence indicate that p40 is creatine phosphokinase B. 1) The amino acid sequences of all peptide fragments of p40 from mouse brain were located in the primary structure of creatine phosphokinase B. 2) p40 of BALB/MK-2 cells was immunoprecipitated with goat antibody against human creatine phosphokinase B. 3) p40 of BALB/MK-2 cells was absorbed to and eluted from a creatine affinity column. 4) Purified creatine phosphokinase B was phosphorylated in vitro by purified protein kinase C, but not by cAMP-dependent kinase or casein kinase II.

Alkaline Phosphatase↗
PubMed1990

Molecular nature of chromosome 5q loss in colorectal tumors and desmoids from patients with familial adenomatous polyposis.

Familial adenomatous polyposis (FAP), which includes familial polyposis coli (FPC) and the Gardner syndrome (GS), is a genetically determined premalignant disease of the colon inherited by a locus (APC) mapping within 5q15-q22. To elucidate the role of 5q loss in FAP tumorigenesis, we analysed 51 colorectal tumors and seven desmoids from 19 cases of FPC and five GS patients, as well as 15 sporadic colon cancers. RFLP analysis revealed a high incidence of allelic deletion in hereditary colon cancers as well as in sporadic colon cancers with a peak at the APC locus. APC loss resulted primarily from interstitial deletion or mitotic recombination. Combined tumor and pedigree analysis in a GS family revealed loss of normal 5q alleles in three tumors, including a desmoid tumor, which suggests the involvement of hemizygosity or homozygosity of the defective APC gene in colon carcinogenesis and, possibly, in extracolonic neoplasms associated with FAP.

Adenomatous Polyposis Coli↗
PubMed1990

A new model for photochemically induced thrombosis in the inner ear microcirculation and the use of hearing loss as a measure for microcirculatory disorders.

A new photochemical method was employed to cause disorders in the inner ear's microcirculation, using the rat as an animal model. Hearing loss was used as a measure for establishing the altered microcirculation. Under pentobarbital anesthesia, the middle ear was opened by a ventral approach. The lateral wall of the cochlea was then illuminated with a filtered xenon lamp (wavelength 540 nm) while rose bengal was infused intravenously. Photoactivated rose bengal produces oxygen radicals and oxygen singlets, which subsequently damage the vascular epithelium to cause the adhesion and aggregation of platelets in the small vessels. Disintegration of the inner ear hair cells at the irradiated site became evident 24 h after the illumination. These findings further suggest that the photochemical occlusion in the inner ear's microcirculation led to ischemic damage of the stria vascularis and the hair cells in the inner ear. When the action potential (AP) of the cochlea was measured with an electrocochleogram a gradual decrease occurred after the illumination. When acetylsalicylic acid was injected intravenously before treatment, the time required to completely suppress the AP was prolonged in a dose-dependent manner. Findings indicate that our method causes a photochemically induced occlusion in the inner ear's microcirculation and is therefore potentially useful for evaluating the various effects of drugs on the ear.

Action Potentials↗
PubMed1990

MR imaging of spastic diplegia. Comparative study between preterm and term infants.

Eighteen children (eleven preterm birth and seven term birth) with clinical evidence of spastic diplegia (SD) were studied to clarify the differences of the lesions between preterm and term SD on MR imaging. All with preterm birth showed similar abnormalities of the periventricular white matter represented by high intensity in T2-weighted imaging and low intensity in T1 imaging. It seemed that the lesions were periventricular leukomalacia (PVL) and dysmyelination pathologically and correlated well clinically with spastic diplegia. SD with term birth group showed various lesions, two brain anomalies (schizencephaly and corpocephaly), one PVL, four showed no lesions. We suggested that SD with preterm birth is not only a clinical but also a pathological entity.

Brain↗
PubMed1990

Two cases of Graves' disease with antithyroid hormone antibodies: implication on the role of thyroglobulin as an antigen.

We have experienced two cases of Graves' disease with antithyroid hormone autoantibodies (Case 1: anti-T4; Case 2: anti-T3) who finally underwent subtotal thyroidectomy after antithyroid drug treatment. Using serial sera obtained before and after operation, the correlation between titers of antithyroglobulin (anti-Tg) and anti-T4 or anti-T3 autoantibodies was examined in each case. There was a significant positive correlation between titers of anti-T4 (Case 1, r = 0.90, p less than 0.05), or anti-T3 (Case 2, r = 0.64, p less than 0.01) and anti-Tg antibodies. Using the homogenate of the thyroid tissue, it was found that the sole iodoprotein in the thyroid gland in each patient was 660 KDa Tg. In addition, Tg purified from the thyroid gland from Case 2 showed different immunological activity with normal Tg in two out of four murine monoclonal anti-Tg antibodies tested. On the other hand, Tg from Case 1 had identical immunological activity with normal Tg in every four monoclonal antibodies. These results are consistent with the view that the antigen responsible for the development of antithyroid hormone autoantibodies is Tg, at least in our two cases. The reason for the persistence of anti-T3 autoantibodies in Case 2, despite the subtotal thyroidectomy, could be due to some unidentified structural abnormalities of Tg which was detected only by the monoclonal anti-Tg antibodies.

Adenoma↗
PubMed1990

An epoxysuccinic acid derivative(loxistatin)-induced hepatic injury in rats and hamsters.

Loxistatin is a possible therapeutic agent of muscular dystrophy. A single oral administration of loxistatin to male rats caused focal necrosis of the liver with inflammatory cell infiltration. The severity of the lesions was dose-dependent up to 200 mg/kg and also manifest by an increase in serum alanine aminotransferase and aspartate aminotransferase activities. Hepatic glutathione (GSH) levels decreased with a maximum 20% depletion within 5 hr after the oral administration of loxistatin. Pretreatment with diethyl maleate did not potentiate the loxistatin-induced hepatic injury. On the other hand, the hepatoprotective effect of cysteamine was observed when cysteamine was administered 24 hr before loxistatin dosing, but the effect was not observed when the antidote was administered concomitantly with loxistatin. Pretreatment of rats with phenobarbital or trans-stilbene oxide provided partial protection against the hepatotoxic effect of loxistatin. Pretreatment with SKF-525A resulted in increased hepatic injury, while pretreatment with piperonyl butoxide, cimetidine, or 3-methylcholanthrene had no effect on hepatic damage by loxistatin. Five hours after [14C]loxistatin administration to rats, the covalent binding of the radioactivity to proteins was greatest in the liver, followed by the kidney, then muscle and blood to a lesser extent. [14C]Loxistatin acid, the pharmacologically active form of loxistatin, irreversibly bound to rat liver microsomal proteins; more binding occurred when the NADPH-generating system was omitted and when the microsomes were boiled first. GSH did not alter the extent of irreversible binding, whereas N-ethylmaleimide decreased the binding of [14C]loxistatin acid to rat liver microsomal proteins by 75%. Unlike the rat, administration of loxistatin to hamsters caused neither hepatic injury nor hepatic GSH depletion even at a high dose (500 mg/kg). Both the distribution and covalent binding of radioactivity in the hamster liver were one-third of those in rats following [14C]loxistatin dosing. These results suggest that loxistatin causes species-specific hepatotoxicity and that, at least in part, some of the toxic effects of loxistatin are mediated by the nonenzymatic covalent binding of loxistatin acid to thiol residues on cellular macromolecules.

Alanine Transaminase↗
PubMed1990

Class II major histocompatibility antigen expression on coronary arterial endothelium in a patient with Kawasaki disease.

To investigate the class II major histocompatibility antigen expression on coronary arterial endothelium of Kawasaki disease and immunophenotypes of the infiltrating cells in the coronary vascular lesions, myocardial sections from a patient who died during the acute stage of Kawasaki disease were studied using an immunoperoxidase technique. The mononuclear cells in the lesions mainly consisted of macrophages and T cells, whereas B cells and NK/K cells were not seen. The majority of T cells reacted with Leu-3a antibodies, and only a few reacted with Leu-2a antibodies. Cells bearing the interleukin-2 receptor, indicative of activated T cells, were also found in the lesions. To determine the distribution of class II antigen, we used anti-HLA-DR antibodies. The massive expression of HLA-DR antigen on mononuclear cells was found in the lesions. In addition, the HLA-DR activation antigen was expressed on the coronary arterial endothelium at the infiltrates in which macrophages and T cells coexisted. In contrast, coronary arterial endothelium did not express HLA-DR antigens in the myocardial tissues of controls (n = 4). HLA-DR+ endothelial cells may play an important role in the development of Kawasaki vasculitis.

Coronary Vessels↗
PubMed1990

Autoimmune thyroiditis induced in mice depleted of particular T cell subsets. III. Analysis of regulatory cells suppressing the induction of thyroiditis.

It has previously been demonstrated that T cell clones with potentials to induce autoimmune thyroiditis exist in lymphoid organs from normal healthy individuals. The present study investigates the nature of regulatory cells co-existing in a normal lymphoid cell population to prevent the activation of these thyroiditis-inducing T cells. T cell-depleted (C57BL/6 x C3H/He) F1 mice (B cell mice) were prepared by adult thymectomy and injection of anti-thymocyte serum, followed by lethal X-irradiation and bone marrow reconstitution. Typical thyroiditis was induced in these B cell mice by i.v. administration of Lyt-1dull T cells but not of whole T cells from normal syngeneic mice. Additional injection of normal thymocytes into B cell mice which had been transferred with the Lyt-1 dull T cells resulted in complete prevention of thyroiditis induction. Mature thymocytes were responsible for this regulatory function and such regulatory cell activity was also found in peripheral lymphoid cells such as spleen cells. These regulatory cells exerted their capacity to prevent thyroiditis in cell dose-dependent and injection timing-dependent manners; thyroiditis was prevented when they were injected in cell doses of greater than 1.5 x 10(7)/mouse and before the initiation of the thyroiditis lesion. Most interestingly, the phenotypes of regulatory cells were Thy-1+ and L3T4+. Since the thyroiditis-inducing Lyt-1 dull T cells has previously been shown to be of L3T4+, these results indicate that there exist functionally heterogeneous subsets in an L3T4+ T cell population and that some L3T4+ T cells function as regulatory cells to prevent the activation of thyroiditis-inducing L3T4+ T cells co-existing in the normal lymphoid cell population.

Animals↗
PubMed1990

T cell clones are killed by a thymic stromal cell monolayer following stimulation of T cell receptor with antigen and/or H-2 molecules on the monolayer.

A thymic stromal cell clone, MRL104.8a, expressed class I and class II H-2k antigens after exposure to gamma-interferon (gamma-IFN) and produced thymic stroma-derived T cell growth factor (TSTGF) irrespective of gamma-IFN exposure. Culturing the keyhole limpet hemocyanin (KLH)-specific, I-Ek-restricted 9-16 helper T cell (Th) clone on an Ia (I-Ak and I-Ek)-expressing MRL 104.8a monolayer induced potent proliferation of the 9-16 cells by virtue of the TSTGF produced by the monolayer. In contrast, the addition of KLH to cultures resulted in lethal growth inhibition of the 9-16 Th clone. Such a phenomenon was also observed for various Th as well as cytotoxic T lymphocyte (CTL) clones, and the following were revealed: (i) the growth of the ovalbumin (OVA)-or bovine thyroglobulin (BTg)-specific Th clone on the la-expressing MRL 104.8a monolayer was also inhibited by addition of the relevant antigen. The fact that these Th clones required antigen-presenting cells (APC) capable of processing antigen for the recognition of the respective target antigen suggested the potential of MRL 104.8a cells for antigen-processing; (ii) the lethal growth inhibition of KLH-specific, I-Ak (23-1-8)- or I-Ek (9-16)-restricted Th clone was prevented selectively by anti-I-Ak or anti-I-Ek antibody respectively; (iii) the I-Ek-alloreactive Th clone (2-13) was supported for its growth on a gamma-IFN-unexposed MRL 104.8a monolayer, whereas this clone was killed on an I-Ek-expressing monolayer; and (iv) when I-Ak-reactive CTL clones were cultured on an Ia- or Ia+ monolayer, CTL clones failed to exhibit cytotoxic effect on either the Ia- or the Ia+ monolayer, but were conversely killed by the Ia+ monolayer. Its killing was also prevented by an antibody which inhibits the recognition of Ia antigen on the monolayer by CTL clones.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Uptake of clarithromycin by rat lung cells.

To evaluate the affinity of clarithromycin (6-O-methylerythromycin A) for lung tissue, the in-vivo and in-vitro uptake of [14C]clarithromycin and [14C]erythromycin by rat lung cells was compared, and the characteristics of the uptake mechanism were investigated. After the administration into the external jugular vein of rats, clarithromycin was found in much higher concentrations in the lung tissue than erythromycin. In isolated lung cells, clarithromycin was also found in greater concentrations than erythromycin. The amount of clarithromycin was ten times that of erythromycin after 5 min incubation. This uptake profile was quite different from that observed in isolated liver cells. Uptake by lung cells for both antibiotics was shown to be an active process, as revealed by the need for cell viability, a suitable environmental temperature and ATP. Clarithromycin uptake proved to be dependent in part upon mitochondrial oxidative respiration. Kinetic analysis indicated that clarithromycin transport was saturable, with a relatively high binding affinity and velocity of uptake. Clarithromycin transport was significantly inhibited by 6-O-methylerythromycin analogues, but was not influenced by other analogues, including erythromycin. Competitive inhibition of clarithromycin uptake was demonstrated by 6,11,12.4"-tetra-O-methylerythromycin, one of the mutual inhibitors. These findings may suggest that clarithromycin utilizes a carrier-mediated transport system in the lung cells, which is common to 6-O-methylerythromycins. This difference of uptake mechanism between both antibiotics may account in part for the greater clarithromycin uptake by the lung cells.

Animals↗
PubMed1990

Further study of mucosal repair by sofalcone in experimental gastritis.

The effect of sofalcone on the glandular structure and cell proliferation in the gastric mucosa of rats with gastritis induced by the administration of sodium taurocholate (TCA) for 6 months was examined by histoquantitative analysis and [3H]thymidine autoradiography. Morphometric observation revealed that, with TCA treatment, mucosal thickness, parietal cell mass, and the ratios of the length of the glandular portion/total length of the gastric gland were decreased in both the fundic and pyloric glands. Inflammatory cell infiltration and collagenous fiber proliferation were present in the gastric mucosa following TCA and indicated the presence of atrophic gastritis. These atrophic changes and inflammatory cell infiltration were reversed by a 3 week administration of sofalcone. Cellular proliferative activity assessed by the labeling indices of the gastric mucosa increased in TCA-induced gastritis in rats. The administration of sofalcone to rats with TCA-induced gastritis significantly increased labeling indices, particularly in the pyloric glands. From these results, it appears that sofalcone stimulates the compensatory increase in proliferative activity of generative cells, which then may become available to heal the gastritis.

Animals↗
PubMed1990

Anti-thyroglobulin autoantibodies in sera from patients with chronic thyroiditis and from healthy subjects: differences in cross-reactivity with thyroid peroxidase.

A significant portion (about 12.7%) of healthy subjects was found to contain anti-thyroglobulin (anti-Tg) antibodies in their sera. We compared the binding activities of these antibodies and of anti-Tg autoantibodies from sera of patients with chronic thyroiditis with human thyroid peroxidase (TPO). The results obtained by ELISA indicated that out of 10 healthy subjects with anti-Tg antibodies, only four had anti-Tg antibodies capable of binding to TPO, whereas anti-Tg autoantibodies from almost all patients with chronic thyroiditis possessed high binding activities to TPO. By use of the immunoprecipitation method, it was also shown that although all anti-Tg autoantibodies from patients precipitated TPO, a majority of anti-Tg antibodies from healthy subjects could not precipitate TPO. Such findings cannot be ascribed to the differences in levels of anti-Tg autoantibodies and anti-TPO autoantibodies in sera and the differences in avidities of anti-Tg antibodies in sera between healthy subjects and patients with chronic thyroiditis. Thus, it can be concluded that anti-Tg antibodies from healthy subjects differ from those of patients with chronic thyroiditis with respect to TPO binding, probably due to difference in fine specificities of these anti-Tg antibodies.

Adolescent↗
PubMed1990

Autobacteriographic studies of clarithromycin and erythromycin in mice.

The antimicrobial activity of clarithromycin was compared with that of erythromycin in experimentally infected mice by whole-body autobacteriography. In mice with systemic staphylococcal infections, the number of vital microbes in the body was relatively low in the early period after oral administration of erythromycin, but increased thereafter to the levels found in nonmedicated control mice. On the other hand, with clarithromycin treatment, a significantly smaller number of microbes was evident throughout the body. The microbes were scarcely seen in the parenchyma of any organs during the examination period. This potent antimicrobial activity of clarithromycin compared with that of erythromycin was further demonstrated in mice with respiratory infections. On the other hand, to examine the distribution properties of both antibiotics in the whole body, an autoradiographic study was carried out with [N-methyl-14C]clarithromycin and [N-methyl-14C]erythromycin. Both labeled antibiotics were distributed widely throughout the body after oral administration in both uninfected control mice and mice with systemic infections. However, the radioactivity was more marked and persistent for [14C]clarithromycin than it was for [14C]erythromycin, particularly in the lungs. The observations described above indicate the superior in vivo antimicrobial activity of clarithromycin compared with that of erythromycin and suggest that the superiority of clarithromycin is largely attributed to its favorable distribution properties. The advantages of whole-body autobacteriography, coupled with whole-body autoradiography, are discussed.

Administration, Oral↗
PubMed1990

Changes in serum autoantibodies to thyroid peroxidase during antithyroid drug therapy for Graves' disease.

Thyroid microsomal antigen is considered to be identical with thyroid peroxidase (TPO). Although there have been many reports concerning changes in microsomal autoantibody during the course of antithyroid drug therapy for Graves' disease, little is known about this matter in relation to TPO autoantibody (TPOab). Therefore, in this paper, we studied serial changes in the latter autoantibody. Initial levels of serum TPOab (% immunoprecipitation) in 13 patients with hyperthyroid Graves' disease ranged from -11.3% to +84.5% (mean +/- SD, 38.9 +/- 31.8%). Of three patients with persistently increased serum TPOab throughout drug therapy, all had recurrence of hyperthyroidism after the drug was discontinued. Of seven patients whose TPOab levels were initially high but subsequently decreased, four had remission of the disease after drug therapy. Inhibition by TPOab of the TPO activity was also demonstrated by both guaiacol and iodide assays, and changes in this inhibitory activity during therapy varied among individuals. This inhibition was not correlated with disease remission. The decrease in serum TPOab observed in some antithyroid drug-treated patients may reflect a decline in disease activity or may be a direct effect of the drug.

Adolescent↗
PubMed1990

[A new application of bull's-eye analysis to lung perfusion scintigraphy].

Technetium-99m macroaggregated albumin lung perfusion scintigraphy was performed and evaluated semiquantitatively by bull's-eye analysis in 24, including 7 with central pulmonary carcinoma, 3 with hypersensitivity pneumonitis (HP), 3 with diffuse panbronchiolitis (DPB) and 11 normal subjects. First, whole lung field was divided into three regions by three concentric circles. And then radial axes were projected from the center to define 36 sectors, 10 degree each. The counts of each sector was calculated and bull's-eye image and circumferential profile curve were displayed. The patient's map was compared with the lower limit of normal (mean-2 SD), and the extent score (ES) and the severity score (SS) were calculated. The ES was 0.25 +/- 0.12 in pulmonary carcinoma (n = 7), 0.08 +/- 0.07 in HP (n = 3), 0.06 +/- 0.04 in DPB (n = 3). The SS was 26.39 +/- 15.17 in pulmonary carcinoma, 4.75 +/- 5.57 in HP, 4.29 +/- 3.67 in DPB. In one case of central pulmonary carcinoma, segmental perfusion defect was evaluated semiquantitatively by bull's-eye image and circumferential profile curve. And in one case of HP, the change of regional pulmonary blood flow could be followed easily using extent and severity map. This new application of Bull's eye analysis to lung perfusion scintigraphy might be useful to evaluate regional pulmonary blood flow.

Alveolitis, Extrinsic Allergic↗
PubMed1990

[Systemic lupus erythematosus accompanied by cutaneous vasculitis. Comparison of molecular size of circulating immune complexes].

Systemic lupus erythematosus (SLE) is a disease caused by immune complexes (IC) and is sometimes accompanied by cutaneous vasculitis at the time of onset or in case of relapse. Usually, however, this manifestation does not newly develop after the beginning of steroid treatment. Here we report on a 16-year-old boy with SLE who developed cutaneous vasculitis 10 days after starting systemic prednisolone treatment despite improvements in clinical and laboratory parameters. We examined the molecular sizes of circulating immune complexes (CIC) through the course of the disease. At the time of admission the CIC were 7S to 19S in size. When the patient developed cutaneous vasculitis, the large component of CIC decreased and the 7S CIC became the major component. Although definitive conclusions cannot be drawn, it is suggested that the shift to the smaller size of the CIC is related to the development of cutaneous vasculitis.

Adolescent↗