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Biomedical subjects

K Okano

Publications and source records attributed to K Okano.

At least 181 records · Page 10Linked to original sources
PubMed1990

[Influence of liquid volume in the middle ear on tympanic membrane vibration (experimental study by holographic interferometry)].

The influence of middle ear liquid on the tympanic membrane (TM) vibration was studied using the holographic interferometry. The physiological saline solution was injected into the middle ear cavity of the canine temporal bone. The liquid volume in the middle ear cavity was changed into 3 grades in order to observe the difference of the vibration pattern between them. The vibratory patterns of a normal canine TM remained unchanged in their first mode up to a frequency of approximately 2 kHz. In this mode, there were peak displacement regions in the posterior and anterior quadrants. The TM vibrations showed sectional patterns, above 3 kHz in the posterior and above 4 kHz in the anterior. After liquid retention, the following were observed. 1. The frequency at which sectional patterns occurred shifted to a lower frequency in the immerged portion, but showed no definite tendency in the unimmerged portion. 2. Maximum amplitudes of the anterior and posterior quadrants of the TM and the mallar tip shifted to somewhat higher frequencies for the liquid volume below the level of the tip portion, but contrary, shifted to lower frequencies for the liquid volume there above. 3. The ossicular chain tended not to make normal function for the TM vibration with an increase of liquid volume.

Animals↗
PubMed1990

Pharmacological activities of a novel thienodiazepine derivative as a platelet-activating factor antagonist.

(S)-(+)-6-(2-Chlorophenyl)-3-cyclopropanecarbonyl-8,11- dimethyl - 2,3,4,5 - tetrahydro - 8H - pyrido[4',3':4,5] thieno[3,2-fl-[1,2,4]triazolo]4,3-a][1,4]diazepine (E-6123) is a newly synthesized platelet-activating factor (PAF) antagonist. The effects of E-6123 on in vitro and in vivo PAF-induced responses were investigated. The IC50 values of E-6123 on 3H-PAF binding to human and guinea pig platelets were 2.7 and 3.0 nmol/l, respectively, and those on PAF-induced platelet aggregation in platelet-rich plasma of human, guinea pig and beagle dog were 10.1, 14.7 and 16 nmol/l, respectively. Oral administration of E-6123 at 3 and 10 micrograms/kg to dogs inhibited ex vivo PAF-induced platelet aggregation in a dose-dependent manner. In guinea pigs, E-6123 at 3 micrograms/kg completely inhibited ex vivo PAF-induced platelet aggregation up to 8 h and the inhibition was still significant at 24 h after administration. Occupancy of the platelet PAF receptor by E-6123 at 3 h and 24 h after administration amounted to 80% and 56%, respectively. Bronchoconstriction induced by PAF injection in guinea pigs was inhibited dose-dependently by oral or intravenous administration of E-6123 at similar doses. The IC50 value of E-6123 at 3 h after oral administration was 1 microgram/kg. Oral administration of E-6123 at 3 micrograms/kg inhibited the bronchoconstriction by more than 90% up to 8 h. Hemato-concentration induced by PAF injection in guinea pigs was inhibited by oral administration of E-6123 at 10 micrograms/kg. E-6123 also protected mice from PAF injection-induced death in a dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

[A case of malignant fibrous histiocytoma of the cecum].

A case of primary malignant fibrous histiocytoma (MFH) of the cecum was reported. Patient was a 52-year-old female, and complained of right lower abdominal pain. The barium enema and abdominal computed tomography demonstrated a localized mass involving the entire circumference of the cecum. Right hemicolectomy was performed and the resected specimen revealed a tumor of 8 X 6 X 5 cm in size extending to the entire circumference of the cecum. The histopathological examination revealed a storiform pattern, which was diagnostic of MHF. The tumor proliferated chiefly in the subserous tissue and partially infiltrated the tunica muscularis propria. The postoperative course was uneventful and she showed no sign of recurrence at 15 months after operation. This is the ninth reported case of primary MFH in digestive organs.

Cecal Neoplasms↗
PubMed1989

Characterization of four different mammalian-cell-derived recombinant human interferon-beta 1s. Identical polypeptides and non-identical carbohydrate moieties compared to natural ones.

In order to evaluate the structural identification of various recombinant human interferon-beta 1s, the recombinant proteins were produced in four different mammalian cells (human PC12 and PC8 lung adenocarcinoma cells, Chinese hamster ovary cells and mouse C127 cells) and characterized. Each mammalian-cell-derived recombinant human interferon-beta 1 represented a single band of 23 kDa on sodium dodecyl sulphate/polyacrylamide gel electrophoresis, the same molecular mass as fibroblast-derived natural human interferon-beta 1. Specific activities, amino acid compositions, amino-terminal sequences, peptide maps on C18 reversed-phase high-performance liquid chromatography and circular dichroic spectra of recombinant proteins were in good agreement with natural ones. On the other hand, the patterns of isoelectric focusing were different between mammalian-cell-derived recombinant human interferon-beta 1s and natural human interferon-beta 1. Sugar composition analysis revealed that the recombinant protein from Chinese hamster ovary cells has a similar sugar composition to that of natural protein and the other recombinant proteins have increased amounts of galactose and glucosamine in comparison to the natural protein. Furthermore, there is no galactosamine in the natural protein, while small amounts of galactosamine were detected in the oligosaccharides released from PC8- and C127-derived recombinant proteins by N-glycanase. These results indicate that mammalian-cell-derived recombinant human interferon-beta 1s have identical polypeptides to those of natural human interferon-beta 1 but their carbohydrate moieties, including unusual N-linked oligosaccharides, are individually different from natural ones and depend on the host cell.

Adenocarcinoma↗
PubMed1989

Phase I study of E1040, a new parenteral cephem antibiotic.

The safety and pharmacokinetics of E1040, a new injectable cephem antibiotic, were evaluated in healthy volunteers. In single-dose studies, 125, 250, 500, 1000 and 2000 mg of E1040 were administered by I.V. infusion over 1 hour. Results of 5 minutes I.V. infusions of 500, 1000 and 2000 mg of the drug were also studied. Plasma concentration-time profiles were well suited to a two-compartment open model. The half-life of elimination from plasma was 1.85 +/- 0.16 hours, and the Cmax and AUC paralleled the doses given. The mean urinary recovery within the first 24 hours was 85.7 +/- 6.43% of the dose. In a multiple-dose study, 2000 mg of E1040 (I.V. over 1 hour) was administered every 12 hours (total 9 times) and no abnormal accumulation of the drug in plasma was observed. There were no significant differences in plasma levels or in urinary recoveries between single- and multiple-dose regimens. There were no subjective or objective abnormal findings definitely attributable to the drug except that one subject given 250 mg over 1 hour reported diarrhea, and another complained of nausea during the infusion of 2000 mg over 5 minutes. From these results E1040 was concluded to be safe and well tolerated.

Adult↗
PubMed1989

Different inhibitory actions of immunomodulating agents and immunosuppressive agents on bone resorption of mouse calvaria.

In this study, we have investigated the in vitro effects of the immunomodulators lobenzarit and traxanox and a newly synthesized immunosuppressant, mizoribine, as well as cyclosporin A, on bone resorption using neonatal mouse calvariae labelled with 45Ca. As stimulators of bone resorption, bovine parathyroid hormone (PTH), lipopolysaccharide (LPS), interleukin 1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) were used. Lobenzarit, traxanox, mizoribine and cyclosporin A inhibited or tended to inhibit bone resorption stimulated by PTH, LPS, IL-1 beta or TNF-alpha in a dose-dependent manner. Basal bone resorption was inhibited by immunosuppressant cyclosporin A or mizoribine, while immunomodulators lobenzarit and traxanox failed to inhibit basal bone resorption. Removal of lobenzarit from the culture medium resulted in the recovery of bone resorptive activity. These results suggest that the inhibitory effect of immunomodulators on bone resorption is reversible and nonselective. Also, it raises the possibility that immunomodulators and immunosuppressants may affect bone resorption by different mechanisms.

Adjuvants, Immunologic↗
PubMed1989

Differences in ability of NO2 absorption in various broad-leaved tree species.

Absorption of nitrogen dioxide (NO(2)) by various broad-leaved tree species was determined by the (15)N dilution method. The tree seedlings were continuously exposed to 0.3 ppm (microl litre(-1)) NO(2) or the mixture of 0.3 ppm NO(2) and 0.1 ppm O(3) for 30 days. The total amount of NO(2)-nitrogen absorbed by a seedling during the 30-day exposure period primarily depended on the size of the seedling. Among the tested tree species, three cultivars of Populus showed the highest rate of NO(2) absorption per unit leaf area, reaching as much as 0.3 mg N per dm(2) per day. The absorption rates for Populus cultivars were more than four times greater than those for Viburnum or Cinnamomum which had the lowest rate. A highly significant correlation was recognised between the rate of NO(2) absorption and the stomatal conductance among the species. Three cultivars of Populus which had the highest rates of NO(2) absorption were most susceptible to the mixture of NO(2) and O(3). On the contrary, Cinnamomum, Viburnum and Quercus, which showed the lowest rate of NO(2) absorption, were very tolerant to the mixed gas. These results indicate that the species difference in susceptibility to the mixture of NO(2) and O(3) was mainly determined by the difference in rate of absorption of these gases. Exposure to NO(2) alone had no detrimental effect on the tested tree species.

Journal Article↗
PubMed1989

Antiulcerogenic compounds isolated from Chinese cinnamon.

Two active compounds that prevent serotonin-induced ulcerogenesis in rats were isolated from Chinese cinnamon (the stem bark of Cinnamomum cassia) and identified as 3-(2-hydroxyphenyl)-propanoic acid and its O-glucoside. The former compound, administered orally or parenterally to rats at a remarkably low dose (40 micrograms/kg body weight), also inhibited gastric ulcers induced by the other ulcerogens such as phenylbutazone, ethanol, and water immersion stress, although it failed to prevent indomethacin-induced ulcers. Pharmacological studies have shown that 3-(2-hydroxyphenyl)-propanoic acid hardly inhibited the secretion of gastric acid, but promoted the gastric blood flow. These results suggest that the antiulcerogenic effect of this compound is probably attributable to the potentiation of defensive factors through the improvement of the circulatory disorder and gastric cytoprotection.

Animals↗
PubMed1989

Phagocytic properties of hepatic endothelial cells and splenic macrophages compensating for a decreased phagocytic function of Kupffer cells in the chronically ethanol-fed rats.

The balance of phagocytic function among Kupffer cells, hepatic endothelial cells and splenic macrophages in the chronically ethanol-fed rats has been investigated. Clearance of latex particles in the blood was measured to estimate the function of the reticuloendothelial system. Phagocytosis of latex particles by Kupffer cells, hepatic endothelial cells or splenic macrophages in vivo was measured by counting the number of ingested particles in a cell after isolation of hepatic nonparenchymal cells or spleen cells following injection of different amounts of latex particles. Latex particle clearance was suppressed in the ethanol-fed rats, demonstrating a decreased phagocytic capacity of the reticuloendothelial system. Markedly decreased phagocytic function was found in 40% of Kupffer cells of the chronically ethanol-fed rats. In contrast, the number of latex particles in hepatic endothelial cells and in splenic macrophages was increased after injection of a triggering dose of latex particles. From these results it may be concluded that an increased phagocytosis of hepatic endothelial cells and splenic macrophages could compensate for the decreased phagocytic function of Kupffer cells.

Animals↗
PubMed1989

[An autopsied case of an aged patient with advanced gastric cancer that showed a complete response to immunochemotherapy].

Described is the case of an 88-year-old male suffering from advanced hemorrhagic gastric cancer who, because of surgical risk factors, was conservatively treated with immuno-chemotherapy in the form of suppositories containing ftorafur (FT-207) and Picibanil (OK-432). The patient showed marked clinical improvement from this therapy. However, his advanced age and other associated complications kept us from performing further examinations, such as an upper-G-I series and a gastrofiberscopy. A year and 4-months later, the patients died of pneumonia and subsequently was autopsied. Macroscopically, his gastric tumor was found to have completely disappeared and had been replaced by a yellowish-white scar tissue. Microscopically, no cancer cells were found in the examined specimens or in the regional lymph nodes.

Adenocarcinoma↗
PubMed1989

[A case of acute mixed leukemia with expression of J5 and GPIIb/IIIa complex by ABC method].

Identification of the lineage and maturation stage of the leukemic cells is essential for the diagnosis, treatment and followup of acute leukemia. Staining of blood smear by avidin-biotin-peroxidase complex method, which requires no special equipments, enables to observe both morphology and surface antigens at the same time. Simultaneous expression of a B-lymphocyte antigen J5 and a platelet antigen GP IIb/IIIa complex on the same blasts was demonstrated by this technique in the present case.

Acute Disease↗
PubMed1989

[A case of dumbbell neurogenic tumor in the posterior mediastinum].

We have recently experienced a dumbbell tumor that developed in the posterior mediastinum in a 64-year-old male. The patient suffered from dorsalgia one year and a half previously. Chest X-ray examinations revealed a well-defined boundary in the right posterior mediastinum. Myelography followed by computerized tomographic scanning (CT) revealed that the tumor developed in a paravertebral area linked with a vertebral canal through an intervertebral foramen and destructed a rib in growing in the paraspinal muscular layer. Longitudinal incision of about 10 cm was made downward from immediately above the first thoracic spinous process, and the chest was opened by posterolateral incision extending into the muscles of the back in an arc shape. The tumor was entirely excised by additional laminectomy. Since malignant schwannoma was diagnosed histologically, Linac X-ray of 50 Gray was given. The patient is now enjoying his healthy daily life with no postoperative complication 2 years after operation. Myelography followed by CT was proved to be quite useful in evaluating a relationship between the tumor and the spinal cord in the diagnosis of this disease.

Humans↗
PubMed1988

Effects of bath-applied L-glutamate and related chemicals on the afferent synapse of the Plotosus electroreceptor.

Tonic electroreceptors of the marine catfish Plotosus were isolated, and effects of chemicals applied in the bath were examined in terms of firing rate (F) responses in single unit afferent nerve. L-Glutamate (L-Glu) and agonists caused marked F increase in the spontaneous discharge. Their potencies, estimated from concentrations for 50% of max F increase, were in the order of quisqualate (2 microM), kainate (7 microM), L-Glu (0.4 mM), L-homocysteate (0.4 mM), D-Glu (3 mM) and L-aspartate (L-Asp, greater than 10 mM). N-Methyl-D,L-aspartate (10 mM) had no effect. L-Glu induced F increase also in the receptors fully suppressed either by cathodal pulses or by high Mg (15 mM), which indicated the postsynaptic action. The synaptic responses were often affected differently in the fast and slow phases, here termed as the peak F and the adapted F, respectively. L-Asp potentiated only the adapted F. Kynurenic acid (Kyn) suppressed only the adapted F, but incompletely and rather dose-independently. Kyn, however, competitively antagonized the amino acid-induced responses. The present results suggest the presence of two distinct postsynaptic receptors, one a Kyn-sensitive Glu receptor that is responsible for part of the adapted F, and the other still undetermined that is responsible for most of the synaptic responses.

Action Potentials↗