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R Kikuchi

Publications and source records attributed to R Kikuchi.

86 records · Page 5Linked to original sources
PubMed1978

[Evidence for existence of type A MAO in mitochondria from human placenta (author's transl)].

The existence of type A and B MAO in mitochondria from human placenta was investigated on the basis of inhibitions by selective MAO inhibitors, such as clorgyline (type A inhibitor) and pargyline and deprenyl (type B inhibitors) with serotonin (substrate for type A MAO), tyramine (substrate for both types of MAO) and beta-phenylethylamine (substrate for type B MAO) as substrates and the results were compared with those obtained with MAO in rat liver. The rates of serotonin, beta-phenylethylamine and benzylamine oxidations by placental MAO were approximately 191, 12 and 48% to those of rat liver MAO, respectively. Placental MAO was more sensitive to tryptic digestion than the enzyme in rat liver. Both MAO's could be separated into two fractions by sucrose density gradient centrifugation, but the two types could not be distinguished when inhibitor sensitivity and substrate specificity experiments were carried out. Placental MAO activity was inhibited by low concentrations of type A inhibitor and was relatively insensitive to those of type B. Simple sigmoidal and identical inhibition curves with various concentrations of either type A or type B inhibitors were obtained with these substrates. These findings suggest that mitochondria MAO in human placenta essentially consists of one distinguishable type of MAO which closely resembles the type A MAO found in other tissues of many species.

Animals↗
PubMed1977

A simple method for beveling micropipettes for intracellular recording and current injection.

A simple equipment for beveling intracellular microelectrodes has been made by modifying a conventional turntable. An agar disc containing ceric oxide polishing compound which was put on a flat glass disc was found to be suitable for beveling of Pyrex single- and double-barreled micropipette electrodes with a tip diameter larger than 0.1 mum. Although the beveled microelectrodes have not always been shown to give better cell penetration into the frog retinal rods than unbeveled find ones, better records could usually be obtained when electric currents were injected into cells, probably being due to their lower resistance, noise, tip potentials and coupling resistance between two barrels.

Electrophysiology↗
PubMed1977

Inefficiency of sanitation measures aboard commercial aircraft: environmental pollution and disease.

Recent investigations at Tokyo International Airport have proven that environmental pollution resulting from the inefficient disposal of human excretion aboard aircraft is an important problem from the standpoint of quarantine. It is, therefore, recommended that the worldwide aviation industry take immediate measures to improve conditions and eliminate this problem, which has thus far been ignored by aircraft designers, airport administration, and CAB personnel.

Aerospace Medicine↗
PubMed1976

Photoelectrolysis using chlorophyll electrodes.

By the conversion of sunlight to chemical energy, photoelectrolysis was carried out using two different chlorophyll-redox compound lining electrodes. These electrodes were prepared by covering platinum plates with chlorophyll and naphthoquinone or anthrahydroquinone and a conducting adhesive. These electrodes exhibit a photoexciting property. The potential was found to shift to a less noble state when the system of the chlorophyll-naphthoquinone electrode was inserted into NAD solution with illumination. On the other hand, the photoexcitation of the system of the chlorophyll-anthrahydroquinone electrode inserted into ferrocyanide solution made the potential more noble. (If the potential in the dark is in the dark is in the positive region of the scheme and the potential moves in the positive direction when the light is turned on, it can be said to be more positive region, it can be said to become less noble, but it is not suitable to say that it becomes more negative.) To make the potential difference between two electodes as big as possible, various factors such as intensity of illumination, molar ratio of chlorophyll to naphthoquinone or anthrahydroquinone and concentration of redox compound in electrolyte were examined. A cell was set up by combining the system of the chlorophyll-naphthoquinone electrode in NAD solution with that of the chlorophyll-anthrahydroquinone electode in ferrocyanide solution, and photoelectrolysis was carried out by closing the external circuit with illumination. The photovoltage between the two electrodes was 0.25 V and the current density was 8 muA/cm2. It was found that NAD was reduced to form NADH at the chlorophyll-naphthoquinone electrode and ferrocyanide was oxidized to form ferricyanide at the chlorophyll-anthrahydroquinone electrode.

Chlorophyll↗
PubMedDate not supplied

Immunohistochemical study of leukocyte infiltration and expression of hsp70 in esophageal squamous cell carcinoma.

It is reported that macrophages and CD4+ or CD8+ cytotoxic T cells have an important role in the suppression of cancer progression. The aim of this study was to clarify these immune responses in patients with esophageal cancer. We enrolled 28 patients with pT2 esophageal cancer that had been resected without preoperative adjuvant therapy. The correlations between the numbers of infiltrating CD4+, CD8+ and CD68+ cells, the expression of heat shock protein 70 (hsp70) and a variety of clinicopathologic factors were analyzed. The numbers of CD8+ T cells and CD68+ macrophages showed a significant positive correlation with tumor diameter (p = 0.01, p = 0.037) and the expression of hsp70 (p = 0.01, p = 0.02) and a negative correlation with lymph node metastasis (p = 0.0079, p < 0.0001). The expression of hsp70 exhibited a negative correlation with lymph node metastasis (p = 0.023). CD8+ T cells and CD68+ macrophages might have a suppressive function against esophageal cancer progression. Our results suggested that hsp70 might play an important role in the presentation of tumor specific antigens.

Aged↗
PubMedDate not supplied

Effect of hypoxia on bronchial reactivity in dogs.

The effect of hypoxia on bronchial reactivity was studied in six anesthetized dogs. Bronchial reactivity was obtained by inhalation of histamine aerosol in stepwise incremental concentrations during fixed tidal volume breathing. Two kinds of hypoxia were induced by inspiration of nitrogen until the end-tidal oxygen concentration (FETO2) reached 15% (mild) and 10% (severe hypoxia). Pulmonary resistance (RL) was measured by the 3 HZ forced oscillation technique in the open chest condition. Before histamine challenge, hypoxia did not increase RL in any of the dogs with mild hypoxia (FETO2 15%) and increased it in one dog with severe hypoxia (FETO2 10%). There was synergy between hypoxia and inhaled histamine in all dogs with both mild and severe hypoxia. The magnitude of synergy was significantly higher in severe than in mild hypoxia (p less than 0.05). With vagi cut, hypoxia did not increase RL compared with normoxia at any histamine concentration. It is suggested that hypoxia enhanced bronchial reactivity through the vagal nerves.

Aerosols↗