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Biomedical subjects

T Okuda

Publications and source records attributed to T Okuda.

At least 235 records · Page 13Linked to original sources
PubMed1993

The secretion of the third component of complement (C3) by human polymorphonuclear leucocytes from both normal and systemic lupus erythematosus cases.

Recently, murine peritoneal exudate polymorphonuclear leucocytes (PMNs) have been proved to secrete complement C3. In this report we show the secretion of C3 by normal human blood PMNs. ELISA assay was used to detect secreted C3 in culture supernatants of PMNs, while immunoperoxidase staining was used for intracellular C3 detection. 12-o-tetradecanoyl phorbol 13 acetate (TPA) had a flushing effect on C3 secretion by PMNs but not macrophages, suggesting a special C3 storing capability in PMNs. Dioctanoyl glycerol, mezerein and calcium ionophore A23187 caused the same marked increase in C3 secretion by PMNs. This suggests the contribution of protein kinase C and the calmodulin pathway in the mechanism of C3 secretion, similar to murine peritoneal exudate PMNs. In some cases of systemic lupus erythematosus, C3 secretion by blood PMNs was increased but no similar response to TPA could be detected.

Cells, Cultured↗
PubMed1993

Effects of flumazenil during administration of midazolam on pial vessel diameter and regional cerebral blood flow in cats.

We implanted closed cranial windows in ten cats in order to observe the response of pial vessel diameter by microscopy using fluorescein isothiocyanate-labeled dextran and regional cerebral blood flow (rCBF) by laser Doppler flowmetry during administration of midazolam and reversal with flumazenil. Midazolam was given at 0.8 mg.kg-1 x min-1 for 10 min and maintained at 0.04 mg.kg-1 x min-1 for 50 min (total 10 mg.kg-1). The diameter of arterioles and venules and rCBF showed no significant change. During the last 10 min of midazolam administration, flumazenil, given at 0.1 mg.kg-1 x min-1 for 10 min (total 1 mg.kg-1), caused an increase of MAP and rCBF (P < 0.01) at 5 min after infusion and diameter of larger arterioles (> 50 microns) and venules (50-100 microns) were dilated (P < 0.05). These results indicate that midazolam does not affect the diameter of cerebral arterioles and venules; however, the reversal effects of flumazenil against midazolam are transient vasodilation of larger arterioles accompanied by an elevation of MAP, and an increase in CBF.

Animals↗
PubMed1993

Antitumor activities of ellagitannins against sarcoma-180 in mice.

Forty-five ellagitannins and related compounds were intraperitoneally injected into mice once, 4 d before intraperitoneal inoculation of S-180 cells, and their antitumor activities were evaluated. When an antitumor-active tannin was defined as one producing a 70% increase or more in the mean life span of mice or one regressor out of six mice, twenty-one ellagitannins were active. Among monomeric ellagitannins, tellimagrandin II was most active. Most of the oligomeric ellagitannins, consisting of tellimagrandins I and II as the monomer unit, had a significant antitumor activity. Macrocyclic ellagitannins were all active. Oenothein B, among them, had the most potent antitumor activity. In contrast, ellagitannins containing a casuarictin or potentillin moiety in their molecules, except for extensively oligomerized ones, showed very low or negligible activity. These results suggest that tannins need the ellagitannin monomer units, having galloyl groups at the O-2 and O-3 positions on the glucose core(s), such as tellimagrandins, in order to exhibit a strong antitumor activity.

Animals↗
PubMed1993

Carbonic anhydrase inhibitors from the pericarps of Punica granatum L.

Seven highly active inhibitors against carbonic anhydrase (CA, EC 4.2.1.1), punicalin (2), punicalagin (3), granatin B (5), gallagyldilactone (7), casuarinin (8), pedunculagin (9) and tellimagrandin I (10), and four weakly active inhibitors, gallic acid (1), granatin A (4), corilagin (6) and ellagic acid (11), were isolated from the pericarps of Punica granatum L. (Punicaceae). They are ellagitannins. The type of inhibition by 3 and 7 using p-nitrophenyl acetate as a substrate, is noncompetitive. The structure-activity relationship of inhibitory effects on CA is discussed.

Animals↗
PubMed1993

Shunt nephritis: efficacy of an antibiotic trial for clinical diagnosis.

Coagulase negative staphylococcus, a normal skin flora, is especially nosopoietic under shunt management, because coagulase negative staphylococcus sometimes forms a biofilm around itself at catheter tips in vivo, which shields the organism from the effects of antibiotics. But it is difficult to distinguish this pathogen from a possible confounding contamination of a blood culture. In this article, we report a case, and discuss how a patient with suspected shunt nephritis should be examined and treated. In addition, to further histological and prognostic interpretation, we review the previously reported cases of shunt nephritis in Japanese adults.

Adult↗
PubMed1993

Tetronothiodin, a novel cholecystokinin type-B receptor antagonist produced by Streptomyces sp. NR0489. I. Taxonomy, yield improvement and fermentation.

Streptomyces sp. NR0489 produces tetronothiodin, a novel brain-type cholecystokinin receptor antagonist. This species was differentiated from its related species S. gelaticus, S. griseolus and S. hydrogenans on the basis of their cultural characteristics, such as the utilization of carbohydrates and the presence or absence of various enzymatic activities. We applied the DNA-DNA hybridization method using photobiotin, which proved the genetic difference between the four species mentioned above. The yield improvement effort including single colony isolation, mutation, and protoplast regeneration together with medium optimization resulted in more than an 81-fold increase of the productivity of tetronothiodin as compared to that of the wild type strain.

DNA↗
PubMed1993

[Interaction of midazolam and vecuronium in anesthetized patients].

The interaction between midazolam and vecuronium was investigated in 60 patients during isoflurane-nitrous oxide-oxygen anesthesia. Neuromuscular function was evaluated by recording the single twitch of the abductor pollicis muscle. Anesthesia was induced with thiamylal 4 mg.kg-1 or midazolam 0.2 mg.kg-1 followed by injection of vecuronium 0.1 mg.kg-1. Observed values after midazolam were compared with those observed in patients with thiamylal. the onset time and the duration of action until 25% recovery were similar with both groups. Midazolam caused no significant potentiation of neuromuscular blocking agents in comparison with the control. Therefore, there was no evidence of any interaction between midazolam and vecuronium during isoflurane-nitrous oxide-oxygen anesthesia.

Adult↗
PubMed1993

Okadaic acid biologically mimics the role of calcium/phospholipid dependent kinase inhibitors in the process of HL-60 cell differentiation.

Okadaic acid, a newly recognized protein phosphatase inhibitor and a non-TPA type tumor promoter, enhanced 1 alpha 25(OH)2D3(D3)-induced HL-60 cell differentiation into monocyte/macrophage lineage but did not affect dibutyryl cyclic AMP (dbcAMP)-induced differentiation into granulocytic lineage. Okadaic acid alone did not induce any differentiation. The process of D3-induced HL-60 cell differentiation on cultivation in magnesium deficient medium can be divided into two steps namely commitment and phenotypic expression as we have previously reported (J Cell Physiol 1987;131:50; Cell Growth Diff 1991;2:415), and the effect of okadaic acid on each step was studied. The results obtained indicated that okadaic acid inhibited commitment and enhanced phenotypic expression. We have previously shown that PKC has a dual action in the process of differentiation, i.e. as a positive regulatory signal in commitment and as a negative one in phenotypic expression. Thus, although okadaic acid has been reported to enhance the phosphorylation of various proteins that are also phosphorylated by PKC, we found that it mimics the role of PKC inhibitors such as H7 and staurosporine in D3-induced HL-60 cell differentiation.

Calcitriol↗
PubMed1993

[Case of diffuse esophageal spasm treated by long myotomy].

Diffuse esophageal spasm is a rare condition, which has generally been treated conservatively in Japan. A case of this disorder treated successfully by long myotomy is reported with a knowledge of prolonged pressure monitoring of the esophagus. A 56-year-old woman was admitted to our hospital with dysphagia. Barium swallow and esophagoscopy showed contraction of the esophagus, and manometry showed normal peristalsis, so the diagnosis of achalasia was ruled out. Prolonged pressure monitoring of the esophagus showed spastic contractions with the pressure over 130 mmHg that continued for 25 sec during meals, which led us to the diagnosis of diffuse esophageal spasm. Extramucosal long myotomy of the esophagus and a modified Belsey Mark IV operation were performed. The postoperative course was satisfactory and esophageal functional tests showed no spasms. The patient regained weight without dysphagia.

Esophageal Spasm, Diffuse↗
PubMed1993

[A case of radiculitis induced by spinal cord electrical stimulation by a percutaneously inserted needle].

Spinal cord electrical stimulation was performed by a percutaneously inserted needle for causalgia of the right upper limb. The end of electrode was positioned along a line extending down the 5th vertebral body in the vicinity of the right 6th cervical nerve root, after which it was permanently implanted following confirmation of desensitizing effects. Although the patient later returned to normal life without requiring any ancillary medication, beginning after a period of roughly six months, the pain suddenly began to increase when stimulated. When stimulated by extracting the electrode 1 cm under fluoroscopic guide, the irritation was relieved somewhat. As radiculitis of 6th cervical nerve was suspected, selective radicular block of 6th cervical nerve was performed. After selective radicular block, the patient's complaint diminished. Based on the above findings, we consider that the physical stimulation caused by the electrode in contact with the nerve root brought about inflammation of the 6th cervical nerve root. This patient was then treated by removing the causative stimulation and selective radicular block of affected nerve, the details of which are reported.

Electric Stimulation Therapy↗
PubMed1993

[Removal of a bronchial foreign body in a child using the laryngeal mask].

The laryngeal mask (LM) was employed for the removal of a bronchial foreign body (screw) in a 2-year-old boy weighing 16 kg since the 6.0 mm external diameter fiberoptic bronchoscope (FBS) for extraction forceps could not be used under tracheal intubation. Anesthesia was induced with sevoflurane in 100% oxygen. After injection of fentanyl 25 micrograms and vecuronium 2 mg, a gastric tube and a size 2 LM were inserted. Throughout the extraction procedure by the FBS in the left main bronchus, the boy had one lung ventilated manually. The airway pressure was kept under 15 cmH2O to avoid gas leakage around the cuff and gastric inflation. Oxygen saturation of 100% with pulse oximetry and PETCO2 of 35 to 45 mmHg with capnometry were maintained. The foreign body was extracted by biopsy forceps. A Fogarty catheter was not effective because the balloon tip was broken by the screw. The LM does not prevent regurgitation and does not provide adequate ventilation under increased airway pressure, but it facilitates the use of a larger size FBS equipped with a variety of extraction forceps. Therefore, it seems to be a useful device for the removal of bronchial foreign bodies in children.

Bronchi↗
PubMed1992

pokkuri, a Drosophila gene encoding an E-26-specific (Ets) domain protein, prevents overproduction of the R7 photoreceptor.

Studies on sevenless and bride of sevenless genes have revealed that the R8 cell plays a key role in the fate of the R7 photoreceptor cell, presenting on its surface an inductive cue to which R7 responds. sev-independent induction of R7 cells has been reported in the seven-up mutation, which appears to transform R1 and R6 cells to R7 cells. We have induced recessive mutations in a gene pokkuri (pok; pokkuri is a Japanese word that means "dropping dead") that lead to overproduction of R7 cells with rather minor effects on outer photoreceptors and R8 cells. Pok protein may function as a transcription factor, as the predicted amino acid sequence contains a region similar to the consensus established for the E-26-specific (Ets) domain.

Amino Acid Sequence↗
PubMed1992

Mouse mammary tumor virus gene expression is suppressed by oligomeric ellagitannins, novel inhibitors of poly(ADP-ribose) glycohydrolase.

Oligomeric ellagitannins (nobotanins B, E, and K) were found to be potent inhibitors of poly(ADP-ribose) glycohydrolase purified from mouse mammary tumor 34I cells. Kinetic analysis revealed that the inhibition of nobotanin B (dimer) was competitive with respect to the substrate poly(ADP-ribose), whereas nobotanin E (trimer) and nobotanin K (tetramer) exhibited mixed-type inhibition. These results suggest that the dimeric structure of ellagitannin may have a functional domain that competes with poly(ADP-ribose) on the poly(ADP-ribose) glycohydrolase molecule. To determine the inhibitory effects of oligomeric ellagitannins on poly(ADP-ribose) glycohydrolase in vivo, we examined their effects on de-poly(ADP-ribosyl)ation of some chromosomal proteins in intact 34I cells that was induced by glucocorticoid treatment. Nobotanin B caused concentration-dependent inhibition of glucocorticoid-induced de-poly(ADP-ribosyl)ation of HMG 14 and 17 and histone H1 in intact 34I cells. Interestingly, this inhibition was associated with suppression of the glucocorticoid-sensitive mouse mammary tumor virus (MMTV) mRNA synthesis. In contrast, nobotanin E and K had little inhibitory effect on either de-poly(ADP-ribosyl)ation of these proteins or induction of MMTV transcription after glucocorticoid treatment. Nobotanin B but not E and K was taken into 34I cells. These results may suggest that the suppression of glucocorticoid-sensitive MMTV transcription results from in vivo inhibition of poly(ADP-ribose) glycohydrolase by nobotanin B. These results also indicate the importance of de-poly(ADP-ribosyl)ation of HMG 14 and 17 and histone H1 in regulation of transcription of the glucocorticoid-sensitive MMTV gene.

Animals↗
PubMed1992

Pharmacologically active tannins isolated from medicinal plants.

Starting with the isolation of a crystalline tannin (geraniin) of mild property from a popular herb medicine (Geranii herba), various polyphenolic compounds including those belonging to new classes of tannins (oligomeric hydrolyzable tannins, complex tannins, and other metabolites and condensates) have been isolated from various medicinal plants. Noticeable biological and pharmacological activities (inhibition of carcinogenesis, host-mediated antitumor activity, antiviral activity, and inhibition of active oxygen, such as inhibition of lipid peroxidation and lipoxygenase, xanthine oxidase, and monoamine oxidase) have been found for several of these polyphenolic compounds.

Animals↗