Search PubMed⌕ Search

Biomedical subjects

M Nishimura

Publications and source records attributed to M Nishimura.

At least 1,261 records · Page 70Linked to original sources
PubMed1984

Developmental changes of glial fibrillary acidic protein and myelin basic protein in perinatal leukomalacia: relationship to a predisposing factor.

Focal white matter necrosis is frequently seen in the brains of infants with perinatal cerebral hypoperfusion. Periventricular leukomalacia (PL) occurs in the deep white matter of premature and term neonates and subcortical leukomalacia (SL) in the subcortical white matter of young infants. Using immunoperoxidase methods in normal infants, glia positive for glial fibrillary acidic protein (GFAP) were found first in the deep zones of white matter and with increasing age they became more prominent in the subcortical zone. They increased diffusely in the deep or subcortical zones of the cases of PL or SL, respectively. The number of myelin basic protein-positive glia is much larger than that of GFAP-positive glia in the cases of old PL. These findings suggest that an increased number of positive glia may be a reaction to hypoxic, ischemic, or toxic insults, or this shifting, transient increase of positive glia in cerebral white matter may be one of several predisposing factors leading to perinatal leukomalacia. Furthermore, positive staining of GFAP and MBP for reactive astrocytes in old PL suggests that at a certain stage of gliogenesis both GFAP and myelin basic protein may be present within the same cell.

Bronchopulmonary Dysplasia↗
PubMed1984

Maturation of catalase precursor proceeds to a different extent in glyoxysomes and leaf peroxisomes of pumpkin cotyledons.

As an approach to study the mechanism of the microbody transition (glyoxysomes to leaf peroxisomes) in greening pumpkin cotyledons, catalase molecules were purified from the two different types of microbody and their structural properties were compared. The purified glyoxysomal catalase was found to consist of four identical subunits (55 kDa), whereas the leaf peroxisomal catalase contains two different forms of monomeric subunit (55 and 59 kDa). These different catalase species cross-reacted with the rabbit antibody raised against the glyoxysomal enzyme. During gel filtration on an Ultrogel AcA 34 column, the leaf peroxisomal 55-kDa polypeptide eluted slightly faster than the leaf peroxisomal 59-kDa polypeptide. The profile of catalase activities exactly paralleled the elution pattern of the 55-kDa molecules, which indicated that the 59-kDa polypeptide was enzymically inactive. Peptide mapping analysis using Staphylococcus aureus protease V8 showed that the glyoxysomal 55-kDa polypeptide was identical to the leaf peroxisomal 55-kDa species, whereas the leaf peroxisomal 59-kDa polypeptide had a different primary structure from the 55-kDa polypeptide. In an in vitro translation system directed by mRNA isolated from etiolated and green cotyledons, glyoxysomal and leaf peroxisomal catalases were synthesized as the identical 59-kDa polypeptide. From peptide mapping analysis, the in vitro-translated 59-kDa polypeptide was found to have a nearly identical primary structure to that of the leaf peroxisomal 59-kDa species. In vivo pulse-chase labeling experiments using etiolated cotyledons showed the conversion of the 59-kDa polypeptide to the 55-kDa molecular species. The overall results strongly indicate that the 59-kDa polypeptide is a precursor form of catalase in pumpkin cotyledons.

Journal Article↗
PubMed1984

Transmembrane orientation of reaction centers in proteoliposomes from Rhodopseudomonas sphaeroides.

The photochemical reaction centers from Rhodopseudomonas sphaeroides were reconstituted with soybean phospholipids into liposomes by the cholate-dialysis method. The transmembrane orientation of the reaction centers in the proteoliposomes and the morphology of the vesicles were investigated. The orientation was determined by the reduction of externally added cytochrome c after its photooxidation by a flash. The structure of the vesicles was examined by electron microscope. Discontinuous sucrose density gradient centrifugation yielded several proteoliposome fractions with different vesicular sizes and reaction-center orientations. The proportion of the reaction centers that exposed their cytochrome c reacting sites to the outside of the vesicles increased from 45 to 85% with an increase of the vesicular size. The proportion also depended on the ionic composition of the dialysis buffer. The optimal ionic environment during the dialysis (100 mM NaCl or 2.5 mM MgSO4) gave a liposome yield of 25-30% with a highly asymmetric orientation (greater than 60%). Entrapping of cytochrome c molecules into the phospholipid vesicles had little effect on the orientation of the reaction centers.

Bacterial Proteins↗
PubMed1984

High-frequency jet ventilation for differential lung ventilation.

High-frequency jet ventilation using a jet injector located at the right mainstem bronchus was superimposed on standard mechanical ventilation to ventilate the injured lung of a patient with unilateral massive atelectasis secondary to pulmonary hemorrhage. This technique of differential ventilation markedly improved arterial oxygenation in this patient and may prove to be a simpler modality of respiratory support in patients who have respiratory failure from unilateral lung disease.

Hemorrhage↗
PubMed1984

Purification of glyoxysomal catalase and immunochemical comparison of glyoxysomal and leaf peroxisomal catalase in germinating pumpkin cotyledons.

As a step to study the mechanism of the microbody transition (glyoxysomes to leaf peroxisomes) in pumpkin (Cucurbita sp. Amakuri Nankin) cotyledons, catalase was purified from glyoxysomes. The molecular weight of the purified catalase was determined to be 230,000 to 250,000 daltons. The enzyme was judged to consist of four identical pieces of the monomeric subunit with molecular weight of 55,000 daltons. Absorption spectrum of the catalase molecule gave two major peaks at 280 and 405 nanometers, showing that the pumpkin enzyme contains heme. The ratio of absorption at 405 and 280 nanometers was 1.0, the value being lower than that obtained for catalase from other plant sources. These results indicate that the pumpkin glyoxysomal catalase contains the higher content of heme in comparison with other plant catalase.The immunochemical resemblance between glyoxysomal and leaf peroxisomal catalase was examined by using the antiserum specific against the purified enzyme preparation from pumpkin glyoxysomes. Ouchterlony double diffusion and immunoelectrophoretic analysis demonstrated that catalase from both types of microbodies cross-reacted completely whereas the immunotitration analysis showed that the specific activity of the glyoxysomal catalase was 2.5-fold higher than that of leaf peroxisomal catalase. Single radial immunodiffusion analysis showed that the specific activity of catalase decreased during the greening of pumpkin cotyledons.

Journal Article↗
PubMed1984

Clinical electrocardiographic studies of bifid T waves.

In 129 electrocardiograms from 129 patients showing bifid T waves as well as U waves the intervals from the beginning of the QRS complex to the two T wave apices (QaT1, QaT2), to the end of the T wave (QeT), and to the apex of the U wave (QaU) were measured. Eighty additional electrocardiograms from matched control subjects showing single peaked T waves were also studied. The precordial distribution of bifid T waves was assessed by calculating lead prevalence indices. This index progressively increased from 2.15 in the age range 20-29 years to 3.72 in the age range 60-69 years, and was significantly higher in patients with left ventricular hypertrophy and ischaemia (4.04) than in those with otherwise normal electrocardiograms (2.35). Thus older age and left ventricular pathology were accompanied by a more leftward location of bifid T waves. Exercise accentuated the bifid nature of the T wave in 12 of 18 patients with otherwise normal electrocardiograms, and diminished it in 11 of 19 cases with left ventricular hypertrophy and ischaemia. When 41 otherwise normal tracings showing bifid T waves were compared with those of 42 matched controls showing single peaked T waves, the QTc was longer and the eTaU interval shorter in the group with bifid T waves. Similarly, 40 patients with left ventricular hypertrophy and ischaemia showing bifid T waves had longer QTc and shorter eTaU intervals than 38 patients with the same diagnosis with single peaked T waves. These findings suggest that right precordial bifid T waves in younger patients with otherwise normal electrocardiograms probably result from delayed right ventricular repolarisation, whereas left precordial bifid T waves in older patients with left ventricular hypertrophy and ischaemia may indicate repolarisation delay in the ischaemic left ventricle.

Adult↗
PubMed1984

Gallium-67 scintigraphy, bronchoalveolar lavage, and pathologic changes in patients with pulmonary sarcoidosis.

The intensity of gallium-67 scintiscans, lymphocyte counts in bronchoalveolar lavage fluid, and pathologic changes were studied in 26 patients with untreated pulmonary sarcoidosis. Noncaseating granulomas were recognized with significantly greater frequency in stage 2 (80 percent; 8/10 cases) than in stage 1 (43 percent; 6/14 cases). Alveolitis showed little relation to the roentgenographic stage. There was a strong correlation between the intensity of gallium uptake in pulmonary parenchyma and the detection rate of granuloma; however, the detection rate of alveolitis was not statistically different from the intensity of gallium uptake. A highly significant correlation was revealed between the lymphocyte counts in bronchoalveolar lavage fluid and the intensity of alveolitis. These observations suggest that the gallium uptake reflects mainly the presence of granuloma, and the lymphocyte count in bronchoalveolar lavage fluid reflects the intensity of alveolitis in patients with pulmonary sarcoidosis.

Adolescent↗
PubMed1984

Interaction between human lymphoblastoid interferon and chemotherapeutic agents in vitro.

The combined effect of human lymphoblastoid interferon (HLBI) and anticancer agents on the growth of MOLT-4 was studied in vitro. The interferon showed a strikingly synergistic interaction in combination with aclarubicin, cytosine arabinoside or prednisolone. It was moderately synergistic in combination with adriamycin or 5-fluorouracil and tended to show additive effects with daunorubicin or vincristine. In vitro studies of combination chemotherapy with interferon and anticancer agents should yield valuable information as to the best combination for man.

Antineoplastic Agents↗
PubMed1984

Involvement of adrenergic and serotonergic nervous mechanisms in allethrin-induced tremors in mice.

Oral or intravenous administration of allethrin, a synthetic derivative of the pirethrin-based insecticides, produces neurotoxic symptoms consisting of mild salivation, hyperexcitability, tremors and convulsions which result in death. Intracerebroventricular injection of allethrin to mouse at about one-nineth the dose of intravenous administration, produced qualitatively identical but less prominent symptoms, indicating that at least some of the symptoms may be originated in the central nervous system. To investigate the mechanism of action of the compound, we studied the ability of agents which alter neurotransmission to prevent or potentiate the effect of convulsive doses of technical grade (15.5% cis, 84.5% trans) allethrin. Intraperitoneal pretreatment with drugs which block noradrenergic receptors or norepinephrine synthesis, such as pentobarbital, chlorpromazine, phentolamine, phenoxybenzamine and reserpine, depressed the tremor induced by allethrin. The inhibitory effect of reserpine was reversed by phenylephrine. Both the serotonergic blocker, methysergide, and the serotonin depletor, rho-chlorphenylalanine, potentiated the effect of allethrin. The potentiating effect of methysergide was antagonized by 5-hydroxytryptamine. However, intracerebroventricular administration of methysergide was ineffective in potentiating the effect of allethrin. alpha 2- and beta-adrenoceptor blockers, muscarinic antagonists, GABA mimenergics and morphine had no effect. These results suggest that allethrin produces its neurotoxic responses in mice by acting on the brain and spinal levels. Furthermore, adrenergic excitatory and serotonergic inhibitory mechanisms may be involved in the neural pathway through which the allethrin-induced tremor is evoked.

Allethrins↗
PubMed1984

Transmitter release at the mouse neuromuscular junction stimulated by cadmium ions.

Cadmium ion (Cd2+) was examined for effects on frequency of miniature end-plate potentials (m.e.p.p.s) under several conditions in mouse diaphragm muscles. Cd2+ depressed potassium (K+)-stimulated rise in m.e.p.p. frequency, acting antagonistically to Ca2+, whereas in the absence of K+ stimulation Cd2+ produced a time- and concentration-dependent rise in m.e.p.p. frequency without affecting the resting membrane potential of muscle fibers. Such a presynaptic effect was observed with or without external Ca2+ [( Ca]0). In the absence of [Ca]0, Cd2+ frequently produced twitching in several fibers, which caused dislodgement of the micro-electrode. Therefore, 10 mM KCl was added to the Ca-free solution to overcome such difficulty. The following experiments were performed in the Ca-free 10 mM KCl solution. Prolonged exposure to Cd2+ led to an eventual decline in m.e.p.p. frequency within 20-30 min. After decline of the effect, m.e.p.p. frequency in the presence of Cd2+ was not restored by adding Ca2+ combined with elevated K+ and with A23187 or by carbonyl cyanide p-trifluoromethoxyphenyl hydrazine and hypoxic condition, each of which was separately effective in enhancing transmitter release. Exposure to 50 microM Cd2+ for 60 min decreased acetylcholine content in diaphragm muscle to approximately 50% of control. Tetrodotoxin and caffeine did not modify the presynaptic stimulatory effect of Cd2+. The effect of Cd2+ on m.e.p.p. frequency was partially reduced by trifluoperazine and phenytoin each of which depressed m.e.p.p. frequency rise induced by Ca2+ with elevated K+. The possible mechanism of Cd2+ action and of its interaction with intracellular Ca2+ stores is discussed.

Acetylcholine↗
PubMed1984

Structural proteins of equine infectious anemia virus and their antigenic activity.

Using purified equine infectious anemia (EIA) virus labeled with 3H-glucosamine or 14C-protein hydrolysate, structural proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. As a result, 2 glycoproteins and 10 proteins with molecular weights (mol wt) ranging from 12,000 to 115,000 daltons were demonstrated. Of 12 structural proteins, 3 proteins, namely a glycoprotein with mol wt of 76,000 (gp76) and 2 proteins with mol wt of 25,000 (p25) and 12,000 (p12), respectively, had distinct antigenic activity from one another in immunodiffusion. Development of antibodies against gp76 and p25 was compared in infected horses. The antibody to gp76 appeared earlier and stronger than to p25 in horses infected with the homologous virus strain. The fraction with glycoproteins was found to have hemagglutinating activity which was inhibited by the serum sample from horses infected with equine infectious anemia virus.

Animals↗