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Biomedical subjects

M Morimoto

Publications and source records attributed to M Morimoto.

At least 253 records · Page 14Linked to original sources
PubMed1990

[Studies of CT images of bronchial tuberculosis, in reference to its pathogenesis].

CT images of 18 patients with bronchial tuberculosis were studied and pathogenesis of the disease was analyzed on the basis of CT findings. Characteristic CT findings, observed in 15 cases, were thickening of bronchial wall and/or swelling of adjacent pulmonary arteries in peripheral part of bronchial tuberculosis lesion. In 11 of these 15 cases, observed pulmonary cavity and/or large tuberculosis lesions at the periphery of the above-mentioned CT findings, were considered to develop to the direct extension from parenchymal tuberculosis. Other 4 cases showed the above-mentioned characteristic CT findings, but without parenchymal lesions, the pathogenesis of the disease remained undetermined. In remaining 3 cases, neither characteristic CT findings nor remarkable parenchymal lesion was noticed. One of them was clarified by bronchoscopic examination.

Adult↗
PubMed1989

Effects of gene dosage on the expression of human growth hormone cDNA in Escherichia coli.

Gene dosage effects on the foreign protein production in Escherichia coli have been analyzed with the expression vectors containing one, two and four tandemly arranged human growth hormone cDNAs under various culture conditions. In a limited synthetic culture medium, a proportional relationship was observed between the number of the integrated cDNA and the amount of human growth hormone produced. With a culture medium rich in the nutrients, however, no such relationship was observed. These results suggest that, under the limited culture conditions, high-level expression of a foreign gene can be achieved by tandemly joined multiple copies of cDNA.

Blotting, Western↗
PubMed1989

Calphostin C (UCN-1028C), a novel microbial compound, is a highly potent and specific inhibitor of protein kinase C.

Calphostin C (UCN-1028C), a newly isolated compound from Cladosporium cladosporioides, is a potent and specific inhibitor of protein kinase C, because it was 1000 times more inhibitory to protein kinase C (IC50, 0.05 microM) than other protein kinases such as cAMP-dependent protein kinase and tyrosine-specific protein kinase (IC50, greater than 50 microM). Calphostin C did not inhibit calcium activated neutral protease (calpain)-digested protein kinase C, indicating that it interacts with the regulatory domain of protein kinase C. In addition this compound showed inhibitory effects on the binding of [3H]PDBu to protein kinase C. The potent cytotoxic activity and antitumor activity of calphostin C might be due to the inhibition of protein kinase C, and thus it may be potentially useful for the therapeutic application.

Animals↗
PubMed1989

Immunoelectron microscopic localization of actin in normal and cholestatic rat hepatocytes.

The immunoelectron microscopic localization of actin in hepatocytes was studied in normal, common bile duct-ligated, and phalloidin treated rats. We used the low temperature embedding procedure with Lowicryl K4M and protein A-gold technique was applied to demonstrate the localization of actin. The tissues embedded in Lowicryl K4M at low temperature provided good preservation of ultrastructure and antigenicity of actin. In control rats bile canaliculi were clearly visualized and most of the gold particles were observed on the bile canalicular microvilli, at the pericanalicular ectoplasm, at the cell border, and on the sinusoidal microvilli. In common bile duct-ligated rats and phalloidin treated rats, pericanalicular ectoplasm was thickened and many gold particles were seen there.

Actins↗
PubMed1989

Projection from the superficial layers of the tectum to the pretectal complex in the cat.

The projection from the superficial layers of the tectum to the pretectal complex in the cat was examined using the retrograde transport of wheat germ agglutinin-horseradish peroxidase. Restricted injections were made into different parts of the pretectum. Neurons in the superior colliculus were found to be arranged in a mediolateral array that corresponds to the rostromedial to caudolateral array of their axon projections to the nucleus of the optic tract and posterior pretectal nucleus. These results suggest that similar parts of the retinotopic maps present in the pretectum and superior colliculus are connected. The labeled cells in the superior colliculus were located within the deep part of stratum griseum superficiale and the superficial part of stratum opticum, and were composed of multipolar cells, vertical fusiform cells and horizontal cells. We conclude from this study that the cells of origin in the superior colliculus originate in the same region to which the contralateral retinal Y-cells project and that have also the morphological diversity, as do other tecto-thalamic neurons.

Animals↗
PubMed1989

Synthesis and antitumor activity of a novel water soluble mitomycin analog; 7-N-[2-[[2-(gamma-L-glutamylamino)ethyl]dithio]ethyl]mitomycin C.

Introducing the mercaptoethyl group at the 7-N position of mitomycin C 1 has led to the isolation of 7-N,7'-N'-dithiodiethylenedimitomycin C 2. The compound 2 showed excellent antitumor activity against sarcoma 180 (sc-ip) and leukemia P388 (ip-ip) in mice. As an extension of this study, we synthesized mitomycin dimers with symmetrical disulfide and mitomycin derivatives with unsymmetrical disulfide at the 7-N side chain. Among these compounds, the water soluble conjugate 3 with ethyl gamma-L-glutamyl-L-cysteinylglycinate was far more effective against sarcoma 180 and leukemia P388 than 1. During the subsequent stage of inquiry for the potent congeners of 3, the compound 4 (water solubility: greater than 500 mg/ml), designated as KW2149, with the gamma-L-glutamylcystamino group at the 7th position was finally selected for further evaluation.

Animals↗
PubMed1989

Bilateral aseptic femoral head necrosis associated with steroid therapy for prolactinoma--case report.

The authors report a recent case of prolactin-secreting pituitary adenoma in a young male who had earlier received treatment for infertility. Following partial adenomectomy, he was placed on postoperative steroid substitution among other treatments, but developed femoral head necrosis several months later. Hormone studies at the time showed significant findings, including an elevated serum cortisol level. The authors conclude that this complication resulted from prolonged steroid therapy and offer suggestions as to how a similar situation may be avoided.

Adult↗
PubMed1989

Calphostins (UCN-1028), novel and specific inhibitors of protein kinase C. I. Fermentation, isolation, physico-chemical properties and biological activities.

A novel complex of calphostin (UCN-1028), which specifically inhibits protein kinase C (PKC) has been isolated from the culture broth of a fungi Cladosporium cladosporioides. Purification of individual components was carried out by silica gel, non-porus resin Diaion HP-20SS and Sephadex LH-20 chromatography, leading to isolation of five closely related components. A, B, C, D and I. Calphostins showed cytotoxic activities against various tumor cells, and these cytotoxicities were proportional to their inhibitory activities against PKC.

Antibiotics, Antineoplastic↗
PubMed1989

UCN-01 and UCN-02, new selective inhibitors of protein kinase C. II. Purification, physico-chemical properties, structural determination and biological activities.

A new inhibitor of protein kinase C (PKC), UCN-01, was isolated from the culture broth of Streptomyces sp. N-126. We have found that this strain also produces UCN-02 which is a stereoisomer of UCN-01. The inhibitors have the molecular formula C28H26N4O4 and have an indolo[2,3-alpha]carbazole chromophore. Their structures have been elucidated by mass and NMR spectra. UCN-01 has been shown to inhibit PKC and protein kinase A (PKA) with IC50 values of 0.0041 and 0.042 microM, respectively, and UCN-02 has been shown to inhibit PKC and PKA with IC50 values of 0.062 and 0.25 microM, respectively. UCN-01 and UCN-02 also showed the cytotoxic effect on the growth of HeLa S3 cells.

Alkaloids↗
PubMed1989

Electrophysiologic effects of TYB-3823, a new antiarrhythmic agent, on isolated guinea pig ventricular muscles.

The effects of a newly synthesized antiarrhythmic agent, TYB-3823 on the transmembrane action potential were examined in isolated papillary muscles of guinea pig. TYB-3823 (3 x 10(-6)-3 x 10(-5)M) caused a dose-dependent decrease in the maximum upstroke velocity (Vmax) and a shortening of action potential duration (APD). In the presence of TYB-3823, trains of stimuli at rates greater than or equal to 0.2 Hz led to an exponential decline in Vmax. This use-dependent block was enhanced at higher stimulation frequency. The time constant for the recovery of Vmax from the use-dependent block was 12.6-13.4 s. The curves relating membrane potential and Vmax were shifted by TYB-3823 (3 x 10(-5)M) to the direction of more negative potentials (5.7 mV). In preparations treated with TYB-3823 (10(-5)-3 x 10(-5) M), the Vmax of test action potentials preceded by conditioning clamp pulses to 0 mV was progressively decreased by increasing the duration of a single clamp pulse or by increasing the number of multiple brief clamp pulses. These findings suggest that TYB-3823 has use- and voltage-dependent inhibitory action on the fast sodium channel by binding to the channel during its activated and inactivated states, and that the unbinding rate of the drug from the channel is very slow. Such characteristics of sodium channel block in combination with APD shortening effect would provide unique antiarrhythmic activities of this substance.

Action Potentials↗
PubMed1989

Transfer of innovation for advancement in dentistry: a case study on pit and fissure sealants' use in Japan.

The implementation of scientific innovations is most important in advancing both dental care systems and dental science. However, scientific knowledge in dentistry is not always well implemented. In this paper the phases of development, diffusion, adoption and utilization of sealants are examined as one example of the way in which a relatively new innovation still needs more effort to ensure its wider use. Discussions with a dental manufacturer on the development of sealant materials and an investigation into the adoption of sealants in the national health insurance system of Japan were undertaken. Questionnaires regarding the education on sealants offered in dental schools and dental hygienist schools, and questionnaires to dental practitioners concerning their use of sealants, were used and analysed. The analysis of the various factors showed that the transfer of knowledge through the educational system is the most significant step in the uptake of innovations. Legality, insurance coverage and patient acceptance are significantly associated with the phase of adoption. A model of transfer pathways for new dental innovations is proposed.

Attitude of Health Personnel↗
PubMed1989

[Evaluation of CT images in pulmonary tuberculosis].

Characteristics of CT images of 40 patients with pulmonary tuberculosis were compared with those of chest radiograms of the same patients, and the clinical usefulness of CT was evaluated. CT findings in pulmonary tuberculosis could be classified as follows. (1) centrilobular shadow, (2) lobular shadow, (3) multilobular shadow, (4) small nodular shadow, (5) pneumonic shadow, (6) cavitary shadow, (7) shadow showing, broncho-vascular dilatation. It was concluded that CT could express far more precisely the location, extension and stage of the tuberculous lesions and could give more informations on the clinical and pathological natures of the lesions than ordinary chest radiograms. Further, CT was superior for the radiological analysis of the detail of the lesions and their distributions.

Adolescent↗
PubMed1988

Visual pretectal neurons projecting to the dorsal lateral geniculate nucleus and pulvinar nucleus in the cat.

We observed morphological subtypes of visual pretectal neurons ascending to the dorsal thalamus, following injections of wheat germ agglutinin conjugated to horseradish peroxidase into the dorsal lateral geniculate nucleus (LGNd) or the pulvinar nucleus. These neurons are composed of fusiform cells and small-sized multipolar cells in the olivary pretectal nucleus, superficial horizontal cells, fusiform cells, small-, medium- and large-sized multipolar cells in the optic tract nucleus, and small- and medium-sized multipolar cells in the posterior pretectal nucleus. When somal size of the neurons projecting to the LGNd was compared to the size of neurons projecting to the pulvinar, the neuronal groups were not identical.

Animals↗