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Biomedical subjects

T Nagano

Publications and source records attributed to T Nagano.

At least 253 records · Page 14Linked to original sources
PubMed1992

Thiobacillus novellus cytochrome c oxidase contains one heme alpha molecule and one copper atom per catalytic unit.

The minimal structural unit of cytochrome c oxidase purified from Thiobacillus novellus was composed of one molecule each of two subunits with molecular masses of 32 and 23 kDa, respectively, and the unit had one molecule of heme a and one atom of copper. In the presence of n-octyl-beta-D-thioglucoside, the oxidase existed as the monomeric form of the unit, while it occurred as the dimeric form of the unit in the presence of Tween 20. The monomeric form showed an active cytochrome c oxidizing activity and reduced molecular oxygen to water with ferrocytochrome c. Namely, it has been shown that the bacterial cytochrome c oxidase with one heme a molecule and one copper atom per molecule can catalyze oxidation of ferrocytochrome c with concomitant reduction of molecular oxygen to water.

Bacillus↗
PubMed1992

Analysis of antigenic determinants shared by two different allergens recognized by human T cells: house dust mite (Dermatophagoides pteronyssinus) and chironomid midge (Chironomus yoshimatsui).

To analyse the cross-reactivity of T-cell-mediated immunity between Dermatophagoides pteronyssinus (Dp) and Chironomus yoshimatsui (Cy), the most common allergens in Japan, we established antigen-specific human T-cell lines and clones. Some but not all of the Cy-induced T-cell lines showed a significant proliferative response not only to Cy, but also to Dp. No T-cell line responded to other unrelated antigens. When we stimulated the Dp-induced T-cell clones with Cy, 3 of the 40 clones (7.5%) showed a significant proliferation, and 2 of the 3 clones produced interleukin-4 and interferon-gamma, indicating their helper function. Cross-reactivity was diminished significantly after the absorption of Dp antigen in an anti-Cy affinity column. The cross-reactive epitopes were thought to be expressed on the Dp molecule of 45-53 kD. The presence of helper T cells reactive to both allergens suggests a possibility that this cross-reactivity might be involved in part in the high incidence of allergy to the 2 major allergens.

Allergens↗
PubMed1992

Effects of norepinephrine on the oxidative pentose phosphate pathway in the rat heart.

To examine whether stimulation of alpha-adrenergic receptors may affect the oxidative pentose phosphate pathway (PPP) in the rat heart, norepinephrine (NE) and the alpha-adrenergic agonist norfenephrine were used. NE was administered as a continuous intravenous infusion in awake rats for 3 days. It stimulated the activity of cardiac glucose-6-phosphate dehydrogenase (G-6-PD), the first and regulating enzyme of the oxidative PPP, in a dose-dependent manner. With the highest dose (0.2 mg.kg-1.hr-1), there was also a time-dependent enhancement. The increase observed after 48 hours was attenuated partially by the beta-receptor blocker metoprolol and the alpha-receptor blocker prazosin. It was entirely abolished when both drugs were administered. Carvedilol, a beta-adrenergic blocker and vasodilator with alpha 1-blocking activity (0.5 mg.kg-1.hr-1), prevented the NE-induced increase in cardiac G-6-PD activity, in functional parameters (heart rate, left ventricular systolic pressure, and left ventricular dP/dtmax), and in the heart weight/body weight ratio. The alpha-adrenergic stimulator norfenephrine increased myocardial G-6-PD activity; prazosin prevented this stimulation. NE and norfenephrine also elevated the available pool of cardiac 5-phosphoribosyl-1-pyrophosphate. G-6-PD activity was enhanced in cardiac myocytes freshly isolated from the left ventricle of rats that had received NE infusion for 3 days (12.3 +/- 1.4 units/g protein) compared with control rats (1.5 +/- 0.4 units/g protein). The activity of 6-phosphogluconate dehydrogenase, one of the enzymes in the oxidative PPP, was elevated only moderately from 12.7 +/- 0.7 to 19.1 +/- 1.4 units/g protein. Combined alpha- and beta-receptor blockade with carvedilol attenuated these effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1992

Bacteriostatic effect of 4,7-dicyanobenzofurazan due to inactivation of 2,3-dihydroxyisovalerate dehydratase.

As part of our research on benzofurazans (BZs), we have reported the bacterioses of BZs in Escherichia coli, which may be due to O2-. produced within E. coli in the presence of dioxygen (O2). Incubation of E. coli with 4,7-dicyanobenzofurazan (1) lowered the 2,3-dihydroxyisovalerate dehydratase activity detectable in extracts from these cells. Addition of branched chain amino acids such as valine and leucine protected E. coli from growth inhibition by compound 1, though it could not protect E. coli from the damage by paraquat (PQ). Addition of Fe(III)-tris[N-(2-pyridylmethyl)-2-aminoethyl]amine (Fe-TPAA), a novel superoxide dismutase mimic, protected the dehydratase in a dose-dependent manner, which confirms that inactivation of the dehydratase is largely due to production of O2-.. The possibility was discussed that the bacteriostatic effect of compound 1 is due to the inactivation of 2,3-dihydroxyisovalerate dehydratase.

Bacteria↗
PubMed1992

New method of detecting nitric oxide production.

Nitric oxide (NO) reacts with H2O2 to produce a rise in potent luminol-dependent chemiluminescence under neutral pH conditions. We applied this reaction to the continuous detection of NO released from the rat isolated perfused kidney with simultaneous pressure changes. Acetylcholine increased NO release dose-dependently with the pressure reduction. An NO synthesis inhibitor, NG-monomethyl-L-arginine, abolished the release. This inhibition was reversed by the addition of L-arginine.

Animals↗
PubMed1992

Application of hemoglobin analysis by CO-oximeter to medico-legal practice with special reference to diagnosis of asphyxia.

Hemoglobin analysis by CO-oximeter is more easily and rapidly available method than other spectrophotometric or GC methods. In the present study, the possibility of diagnosis of asphyxia by CO-oximeter was examined experimentally using rabbits. When measured value of oxyhemoglobin (O2Hb) was lower than about 20% and that of deoxyhemoglobin (HHb) was, on the other hand, higher than about 80%, being accompanied by low measured values of both methemoglobin (MetHb) and CO-hemoglobin (COHb) (< 5%), asphyxia should be firstly considered as the cause of death. To the corpses found at the scene of fire, three chief factors causing death such as burns, suffocation due to oxygen deficiency and intoxication by poisonous gases may have occurred simultaneously, and through measuring the values of O2Hb, COHb, MetHb and HHb, the main lethal factor could be selected out among these three factors above and the cause of death could be examined much more closely. Because of easy and rapid analysis, it could be considered that CO-oximeter was useful for forensic practices and police activities.

Animals↗
PubMed1992

Ultrastructural analysis of platelet-like particles from a human megakaryocytic leukemia cell line (CMK 11-5).

Ultrastructural observations were performed to further characterize the human megakaryocytic leukemia cell line, CMK, and its subclone, CMK11-5. We found that particles derived from CMK11-5 cells had cytoplasmic projections and no nucleus, and that some particles contained alpha granules. Incubation with ADP induced fibrinogen receptors on the surface of these particles. Furthermore, the particles had glycoprotein Ib antigen on their surfaces, and attached nonreversibly to rabbit aortic subendothelium, showing associated morphological changes similar to those observed in normal platelets. CMK and CMK11-5 are the first megakaryocytic cell lines that have been found to release particles that have some of the same functions as normal platelets. In particular, CMK11-5 seems to be a useful model for studying megakaryocyte function.

Blood Platelets↗
PubMed1992

The immunocytochemical localization of tumour necrosis factor and leukotriene in the rat liver after treatment with lipopolysaccharide.

After administration of bacterial lipopolysaccharide, there is an increase in the number of leucocytes which adhere to the endothelial cell surface of the hepatic vessels and pass through the endothelial layer by comparison with controls. There is also marked endothelial cell damage including intracytoplasmic oedema, increased numbers of autophagic vacuoles and dilatation of the intercellular junction in LPS-treated samples. The presence of immunocytochemical products of leukotriene (LTR) and tumour necrosis factor (TNF) was examined using in both LPS-treated and control samples. Immunoreactions of LTR which were seen in specific granules of neutrophils and monocytes attached to the endothelial cell surface may indicate the onset of endothelial cell damage. Positive immunoreactions of TNF on the endothelial cell surface, seen only in LPS-treated samples, indicate that TNF may enhance the passage of blood cells through the endothelia and also increase the endocytotic activity of the liver parenchymal cells, as revealed by the present marker experiment using horseradish peroxidase. Positive reactions of TNF in lysosomes of the endothelial cells suggest that they are able to produce TNF and transport it to the cell surface.

Animals↗
PubMed1992

[A case report of replacement of the extracardiac conduit for tetralogy of Fallot: reconstruction with autogenous tissue around the conduit].

Replacement of the valved extracardiac conduit with autogenous tissue was performed on a 13-year-old female. The procedure was based on that reported by Danielson in 1987. She underwent the first operation for tetralogy of Fallot with pulmonary atresia using a valved extracardiac conduit (#16 mm Björk-Shiley valve) 8 years ago. Recently, she complained exertional dyspnea and chest pain. Reoperation was scheduled because of bleeding tendency, somatic growth of the patient, and severe distal anastomotic stenosis of the conduit by right ventriculogram. At operation, the valved conduit was removed under cardiopulmonary bypass, and autogenous connective tissue around the conduit was preserved as the posterior wall of the new conduit. An onlay patch (pericardial monocusp patch) was sutured to form the roof of the new tract. Postoperative catheterization showed no residual stenosis or pressure gradient between the right ventricle and the pulmonary artery. This technique is useful as the replacement of extracardiac conduit because of its simplicity, no necessity of postoperative anti-coagulant therapy, and possibility to make a generous-sized new outflow tract.

Adolescent↗
PubMed1992

[Surgical treatment under extracorporeal circulation for renal cell carcinoma with tumor thrombus in inferior vena cava].

Three cases of renal cell carcinoma with tumor thrombus extending into the inferior vena cava are reported. Radical nephrectomy and thrombectomy were performed under extracorporeal circulation in all the cases. The level of tumor thrombus was preoperatively determined by computed tomography, magnetic resonance imaging or venacavography. The tumor thrombus extended into the right atrium in one, and above the hepatic vein in two cases. One patient whose thrombus reached the right atrium died of multiple metastasis of renal cell carcinoma 5 months after operation. Another patient with lung metastasis was given interferon-alpha and is alive 5 months after operation. The other patient is clinically free of disease and in good health 7 years after operation. We believe that extracorporeal circulation allows an opportunity to resect the tumor thrombus in a controlled situation, and makes the operation safer.

Aged↗
PubMed1992

Light-induced retinal damage in mice. Hydrogen peroxide production and superoxide dismutase activity in retina.

The oxidative mechanism in retinal damage due to exposure to intense light was investigated histochemically and biochemically. SMA mice (albino mice) of 2 to 3 months of age were exposed to intense light (1000-1400 lux). In the cyclic light-reared group (without dark adaptation), the outer and inner segments of the photoreceptor cells were damaged after 3 days of exposure, and severe outer nuclear layer damage was observed after 5 to 7 days of exposure. Hydrogen peroxide (H2O2) production in the outer nuclear layer increased with the progress of retinal damage. In the dark-reared group (dark adaptation of 16-18 hours), outer and inner segment damage was noted after 4 hours of light exposure, and severe outer nuclear layer damage was noted after 12 hours of light exposure. H2O2 production increased in the outer nuclear layer with retinal damage. Superoxide dismutase (SOD) activity did not change before the occurrence of retinal damage, and decreased by 25% after 3 days of exposure to light in the cyclic light-reared group. The decrease in total SOD activity corresponded to that of manganese-SOD (Mn-SOD). In the dark-reared group, SOD activity did not change, even after 1 day of exposure. There appears to be some relationship between retinal light damage and H2O2 production in the outer nuclear layer. Superoxide dismutase activity failed to provide protection against retinal oxidative damage due to intense light exposure.

Animals↗
PubMed1991

Diagnosis of paraaortic and pelvic lymph node metastasis of gynecologic malignant tumors by ultrasound-guided percutaneous fine-needle aspiration biopsy.

Transabdominal ultrasonography was done in patients with gynecologic malignancies to detect paraaortic and pelvic lymphadenopathy. Of the 78 patients who underwent ultrasonic examination of pelvic lymph nodes, pelvic lymphadenopathy was detected in 24, of whom ultrasound-guided percutaneous fine-needle aspiration biopsies (FNAB) were done in 16. Of these 16 patients, the results of 13 biopsies were positive. Of the 41 patients who underwent ultrasonographic examination of the paraaortic lymph nodes, 27 had paraaortic lymphadenopathy. Ultrasound-guided percutaneous FNAB were done in 26 of these 27 patients, with positive findings in 21 of the 26. It was concluded that ultrasound-guided percutaneous FNAB is useful in detecting metastatic lymph nodes in gynecologic malignancies.

Abdominal Neoplasms↗
PubMed1991

Cytochromes c of Nitrobacter winogradskyi and Thiobacillus novellus: structure, function and evolution.

The amino acid sequences of Thiobacillus novellus and Nitrobacter winogradskyi cytochromes c have been compared with those of cytochromes c from several other organisms. The two bacterial cytochromes resemble eukaryotic cytochromes c; 49 amino-acid residues are identical between T. novellus and horse cytochromes c, and 50 residues identical between N. winogradskyi and horse cytochromes c. However, their reactivity with cow cytochrome c oxidase is about 80% lower than the reactivity of eukaryotic cytochromes c with the cow mitochondrial oxidase, while they react with yeast cytochrome c peroxidase as rapidly as eukaryotic cytochromes c. The numbers of identical amino-acid residues between T. novellus and animal cytochromes c are 45-53 and those between N. winogradskyi and animal cytochromes c 47-53, while those between the two bacterial cytochromes and yeast and protozoan cytochromes c are around 40. Thus, N. winogradskyi and T. novellus cytochromes c are more similar to animal cytochromes c than to yeast and protozoan cytochromes c on the basis of the amino-acid sequence.

Amino Acid Sequence↗
PubMed1991

Identification and expression of boar sperm proteins in the reproductive tract that interact with antibodies in serum from an infertile woman.

Serum designated as IS obtained from a young healthy infertile woman induced a head-to-head agglutination of ejaculated boar sperm. The immunoglobulin G (IgG) prepared from IS localized to the acrosomal region of the sperm head obtained from the corpus and cauda epididymis as determined by an indirect immunofluorescent method. The IgG interacted with a boar sperm protein with an estimated molecular weight of 45-kDa, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoretic (SDS-PAGE) immunoblotting technique. However, the IgG did not interact with proteins extracted from sperm obtained from the testis and caput epididymis or from non-gonadal tissues including liver, kidney, spleen, muscle and serum. The IgG interacted with additional proteins of about 75- and 38-kDa present in the corpus and cauda epididymal fluids but not those in the caput epididymal fluid. The staining intensity of the 75-kDa band was reduced and that of the 38-kDa was nullified with ejaculated seminal plasma proteins. The interacting proteins were adsorbed when chromatographed on Concanavalin A Sepharose column, suggesting that they are glycoproteins.

Agglutination Tests↗
PubMed1991

Three-dimensional model of tight junction fibrils based on freeze-fracture images.

To study the three-dimensional structure of tight junction fibrils, the epithelia of the jejunum and epididymis of adult mice were examined by the freeze-fracture technique in unfixed and in aldehyde-fixed specimens. The fibrils have a stronger affinity for the protoplasmic (P) face of the lipid bilayer in fixed material, and for the external (E) face in unfixed and rapidly frozen material. Therefore we can observe the fibrils both from the outside and inside of the cell. Fibrils appearing on the P-face are smoothly contoured ridges and rows of hemispherical particles, while those appearing on the E-face are exclusively rows of hemispherical particles. Based on these observations, we wish to propose a new fibril model for the tight junction. There are two distinctive types of junctional elements. One type is composed of a smooth and continuous strand in the external view of the cell, but is studded with hemispherical bulgings in its internal view. This type will be referred to as the "continuous type". The other type is bead-like, and will be referred to as the "particle type". The relative proportion of these two types of elements appearing within a tight junction network differs among tissues.

Animals↗
PubMed1991

Distribution of actin-filament bundles in myoid cells, Sertoli cells, and tunica albuginea of rat and mouse testes.

Frozen sections of the rat and mouse testes were stained with either FITC-phalloidin or NBD-phallacidin and viewed with conventional fluorescence and confocal laser microscopes in order to demonstrate the arrangement of actin-filament bundles in myoid cells, Sertoli cells and tunica albuginea. Myoid cells are rich in actin-filament bundles crossing at right angles. These bundles running in different directions can also be visualized by means of electron microscopy. Nerve fibers occur in the vicinity of myoid cells, suggesting a neural control of the cell. At Sertoli cell junctions actin filaments occur at the circumference of the cell, where they show a honeycomb pattern. The ratio of the number of Sertoli cells per myoid cell can be calculated by means of confocal microscopy; this technique may provide a new parameter for determining spermatogenic activity. In the tunica albuginea of the juvenile mouse testis, actin filaments are arranged in an alternate fashion.

Actins↗
PubMed1991

Immunohistochemical study on the localization of the epitope defined by a human saliva-specific mouse monoclonal antibody (P4-5C).

A novel mouse monoclonal antibody (P4-5C) has been developed which recognizes the core portion of the protein carrying ABO(H) blood group antigens in human saliva. This proved to be specific for human saliva using immunochemical investigations such as enzyme-linked immunosorbent assay, Ouchterlony method and counter-immunoelectrophoresis. By light and electron microscope studies with immunohistochemical techniques using this human saliva-specific P4-5C as primary antibody, it was shown that P4-5C reacted specifically and exclusively with mucus from the mucous gland cells of human salivary glands. P4-5C reacted neither with the mucous gland cells of other primates (hamadryas baboon, Japanese monkey and Rhesus monkey) and four mammals (dog, cat, rabbit and mouse) nor with other human tissues. The epitope on the core portion of the ABO(H)-carrying protein was defined by P4-5C and could be discriminated from the epitope of ABO(H) blood group antigens using immunoelectronmicroscopy, although these 2 epitopes were localized relatively close to each other. The P4-5C monoclonal antibody can be also used for morphological species identification of tissue specimens from submandibular glands.

ABO Blood-Group System↗