PubMed Health⌕ Search

Biomedical subjects

M Kondo

Publications and source records attributed to M Kondo.

At least 19 recordsLinked to original sources
PubMed1992

[The biotransformation of NSAIDs: a common elimination site and drug interactions].

Many NSAIDs are eliminated predominantly through hepatic biotransformation in man. We have studied, in human hepatic microsomes, the role of specific cytochrome P450 isozymes in the formation of the major metabolites of oxicam (piroxicam and tenoxicam), phenylacetic (diclofenac) and propionic acid (ibuprofen) derivatives. A common isozyme (P450TB, CYP2C subfamily) controls the major elimination pathway of these NSAIDs. We have also determined, in two in vitro models of P450TB, the affinity for this isozyme of NSAIDs from other chemical classes (acetylsalicylic acid, mefenamic acid and indomethacin). All NSAIDs tested displayed a high affinity (3-300 microM) for cytochrome P450TB. Cytochrome P450TB plays a major role in the elimination of several NSAIDs with different chemical structures. NSAIDs are substrates as well as potential inhibitors of cytochrome P450TB. Their elimination can therefore be reduced by concomitant administration of known inhibitors of P450TB (antifungals, antibacterial sulfonamides, calcium channel blockers).

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Discriminative affinity labelling of opioid receptors by enkephalin and morphiceptin analogues containing 3-nitro-2-pyridinesulphenyl-activated thiol residues.

The thiol groups of leucinthiol, cysteamine and cysteine incorporated into opioid peptides enkephalin and morphiceptin were activated by the 3-nitro-2-pyridinesulphenyl (Npys) group to form mixed disulphides highly reactive to a free thiol. Enkephalin analogues containing Npys-leucinthiol or -cysteine at positions 4, 5 and 6 exhibited high affinities for both mu and delta receptors, while morphiceptin analogues containing Npys-cysteine at positions 4 and 5 showed relatively weak affinity only for mu receptors. When these S-activated opioid peptides were incubated with rat brain membrane preparations, it was found, by binding assay using radiolabelled and non-labelled [D-Ala2,MePhe4,Gly-ol5]enkephalin, that they label mu opioid receptors in a dose-dependent manner. The concentrations required to label half of the receptors were 0.2-2 microM for enkephalins and 10-30 microM for morphiceptins. These results suggested that the thiol group labelled by S-activated enkephalins and morphiceptins is present in the ligand binding site of receptor protein, but not in GTPase-binding protein.

Affinity Labels↗
PubMed1992

Secretion of endothelin-1 in human endothelial cell line but not in B cell line by transfection of preproendothelin-1 cDNA.

Stable transformants with preproendothelin-1 (preproET-1) cDNA were established for the study of the regulation of endothelin-1 (ET-1) biosynthesis in human cells. ET-1, a potent vasoconstrictor peptide, is produced by endothelial cells and is secreted into the blood at a low level. Human preproET-1 cDNA was introduced into two immortal human cell lines, t-HUE2, an endothelial cell line, and Raji, a B cell line, with Ecogpt selection. Several stable transformants of t-HUE2 expressed extraordinarily high levels of preproET-1 specific mRNA and secreted ET-1 into serum-free culture medium, while the transformants of Raji cells expressed high levels of ET-1 mRNA, but secreted a negligible amount of ET-1. Immunocytochemical studies of intracellular ET-1 content revealed that there were some defects in the translation or processing of preproET-1 in the B cell line transformants. In addition, the ratio of ET-1 to ET-1 precursor (big ET-1) was much higher in the t-HUE2 transformants than in normal endothelial cells, suggesting that t-HUE2 transformants (for example t-HUE2-1) possess high levels of endothelin converting enzyme (ECE). The establishment of stable transformants producing high levels of ET-1 in serum-free medium will be useful for the study of cell-type-specific translation and processing to mature ET-1, and of the regulatory factors of ECE.

B-Lymphocytes↗
PubMed1992

Solid-liquid phase boundaries of lens protein solutions.

We report measurement of the solid-liquid phase boundary, or liquidus line, for aqueous solutions of three pure calf gamma-crystallin proteins: gamma II, gamma IIIa, and gamma IIIb. We also studied the liquidus line for solutions of native gamma IV-crystallin calf lens protein, which consists of 85% gamma IVa/15% gamma IVb. In all four proteins the liquidus phase boundaries lie higher in temperature than the previously determined liquid-liquid coexistence curves. Thus, over the range of concentration and temperature for which liquid-liquid phase separation occurs, the coexistence of a protein crystal phase with a protein liquid solution phase is thermodynamically stable relative to the metastable separated liquid phases. The location of the liquidus lines clearly divides these four crystallin proteins into two groups: those in which liquidus lines flatten at temperatures greater than 70 degrees C: gamma IIIa and gamma IV, and those in which liquidus lines flatten at temperatures less than 50 degrees C: gamma II and gamma IIIb. We have analyzed the form of the liquidus lines by using specific choices for the structures of the Gibbs free energy in solution and solid phases. By applying the thermodynamic conditions for equilibrium between the two phases to the resulting chemical potentials, we can estimate the temperature-dependent free energy change upon binding of protein and water into the solid phase.

Animals↗
PubMed1992

Alpha-elastin coacervate as a protein liquid membrane: effect of pH on transmembrane potential responses.

A protein liquid membrane composed of coacervated alpha-elastin, a chemical fragmentation product of the biological elastic fiber protein, functioned as an amphoteric liquid ion-exchange membrane. Ionic permselectivities of the alpha-elastin coacervate membrane to a series of metal chlorides were investigated for the concentration-cell systems by the ordinary electrochemical measurements. Effects of pH on the transmembrane potential responses for NaCl, CaCl2, and MgCl2 systems were examined. Only in the Ca(2+)-containing system did potential responses stay at constant levels against the pH changes, whereas in the other systems, increasing pH caused potential changes, indicating an improvement of cationic permselectivity across the alpha-elastin coacervate membrane. It was suggested that the characteristic Ca2+ transport mechanisms across the alpha-elastin coacervate membrane are related in some way to the polypeptide backbone interactions specific and selective to Ca2+ ions.

Calcium↗
PubMed1992

Possible role of free radicals in the chronic inflammation of the gut.

Recent studies have demonstrated that intracolonic administration of trinitrobenzenesulfonic acid (TNB) dissolved in ethanol produces chronic colitis in rats, and that this model shares many features of human inflammatory bowel disease (IBD), particularly Crohn's disease. We investigated the role of free radicals in the pathogenesis of this colitis model. In the early stage of this colitis, antioxidant enzymes (such as superoxide dismutase, glutathione peroxidase) and an antioxidant, alpha-tocopherol, were significantly decreased with the severity of colonic damage. Mn-SOD at a dose of 50000 U/kg attenuated this colitis when preadministered subcutaneously one hour before the induction of colitis. These results suggest that oxygen-derived free radicals may play an important role in this colitis.

Animals↗
PubMed1992

Histochemical study on the maturation of human megakaryocytes using microfluorometry.

A microcytofluorometrical DNA measurement was basically studied and was applied to single megakaryocytes previously identified on a Wright-Giemsa stained smear. The smear was first photographed and the location of each megakaryocyte was recorded on a cell map. The smear was then bleached with 50% acid ethanol and absolute methanol, and re-stained with 4',6-diamidino-2-phenylindole (DAPI) reagent (pH 7.4) at 4 degrees C. Nuclear blue fluorescence was observed and the intensity of this fluorescence was proportional to the amount of DNA with the coefficient of variation (CV) of 3.6% when stained for 30 min. After 30 min DAPI staining, the DNA measurement was microcytofluorometrically performed in single megakaryocytes which had been morphologically classified into 4 groups on the basis of cytoplasmic maturation, Bessis' classification, assessed on Wright-Giemsa-stained bone-marrow smears from normal human beings. The histograms of the cells did not show any difference in DNA ploidy distribution among the classes: that is, the DNA histograms disclosed ploidy distribution from 4 N to 64 N with the largest population of 16 N. These findings suggest that nuclear DNA synthesis is completed before platelet production starts. This method is useful for comparing the morphological features and DNA content of single megakaryocytes.

Bone Marrow Cells↗
PubMed1992

Effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on cytotoxicity of PSK-induced peritoneal polymorphonuclear leukocytes (PMNs).

We investigated whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) enhanced the cytotoxicity of PSK-induced polymorphonuclear leukocytes (PMNs) in the peritoneal cavity. Male C3H/He mice, 8- to 10-week-old, received single subcutaneous (s.c.) or intraperitoneal (i.p.) injection of 2.5 micrograms/animal of rhG-CSF at different time points before or after an i.p. administration of PSK. In other experiments, mice were s.c. or i.p. treated with the same dosage of rhG-CSF every day for 7 or 14 consecutive days and i.p. injected with 2.5 mg/animal of PSK on the last day. Peritoneal PMNs were harvested 6 hrs after the administration of PSK and purified to more than 95% by Ficoll-Paque for in vitro cytotoxic assay. In vitro cytotoxic assays with 51Cr labeled MM46 mammary carcinoma cells were added with 5-20 micrograms/ml of Nocardia rubra cell wall skeleton (N-CWS) at the beginning of the assay to augment the cytotoxic activity of PMNs. In vitro addition of rhG-CSF to the assay did not enhance the cytotoxicity of PSK-induced PMNs. However, the cytotoxicity was significantly increased when rhG-CSF was s.c. administered 12 hrs before a PSK injection or 2 or 5 hrs after that. On the other hand, the cytotoxicity was rather weak when mice s.c. or i.p. received consecutive injections of rhG-CSF. This cytotoxicity may be mediated by H2O2, since H2O2 production of PMNs during the cytotoxic assay appears to correlate with the levels of cytotoxicity under suppressed H2O2 generation by catalase or enhanced generation by rhG-CSF. These results suggest that rhG-CSF augments the cytotoxicity of PSK-induced PMNs when administered in vivo timely.

Animals↗
PubMed1992

In vitro augmentation of cytotoxicity by N-CWS in peritoneal polymorphonuclear leukocytes (PMNs) induced by PSK, OK-432 or N-CWS.

Peritoneal polymorphonuclear leukocytes (PMNs) were collected from the peritoneal cavity of C3H/He mice 6 hrs after intraperitoneal (i.p.) injection of 2.5 mg/head of PSK, 1 KE (100 micrograms)/head of OK-432 or 200 micrograms/head of Nocardia rubra cell wall skeleton (N-CWS). Without in vitro stimulation, these PMNs did not show cytotoxicity to syngeneic MM46 mammary carcinoma cells in 51Cr release assay. Cytotoxicity of these PMNs was augmented by the addition of 25 micrograms/ml of N-CWS but not of PSK or OK-432 to cultures for the assay at the beginning of the culture. H2O2 production of PSK-induced PMNs was increased by the in vitro addition of 25 micrograms/ml of N-CWS but not of PSK. These results suggest that PSK as well as OK-432 and N-CWS can induce PMNs capable of responding further to N-CWS as the second stimulant.

Adjuvants, Immunologic↗
PubMed1992

Effects of a platelet-activating factor antagonist, CV-6209, on gastric mucosal lesions induced by ischemia-reperfusion.

Recent research was shown that oxygen-derived free radicals are involved in the pathogenesis of various diseases, including ischemia-reperfusion injury. We have also reported that oxygen-derived free radicals and lipid peroxidation may play an important role in gastric mucosal injury induced by ischemia-reperfusion. The hypoxanthine-xanthine oxidase system and neutrophils are considered important sources of oxygen-derived free radicals in this process. In recent years, it also has been shown that serum platelet-activating factor (PAF) levels increased during ischemia-reperfusion, and that induction of superoxide generation by neutrophils is one of the important biological effects of PAF. In the present study, we examined the effect of CV-6209, a specific PAF receptor antagonist, on gastric mucosal injury induced by ischemia-reperfusion, to shed some light on the possible involvement of PAF in such lesions. CV-6209 significantly attenuated the gastric mucosal injury induced by ischemia-reperfusion, and inhibited both an increase of thiobarbituric acid reactive substances and a decrease of alpha-tocopherol in gastric mucosa after ischemia-reperfusion. However, CV-6209 had no effect on gastric mucosal blood flow during ischemia-reperfusion. These results suggest that endogenous PAF may play an important role in gastric mucosal injury induced by ischemia-reperfusion, and that CV-6209 exerts its beneficial effect mainly by inhibiting neutrophil superoxide production induced by PAF.

Animals↗
PubMed1992

Thromboxane A2 mimetic U46619 stimulates ciliary motility of rabbit tracheal epithelial cells.

To elucidate whether thromboxane A2 (TxA2), one of the important arachidonic acid metabolites that may play a role in the development of airway inflammation, affects respiratory ciliary motility and, if so, what the mechanism of action is, we measured ciliary beat frequency (CBF) of rabbit cultured tracheal epithelium in response to U46619, a TxA2 mimetic agonist, by a photoelectric method. Addition of U46619 (10(-5) M) increased CBF from 17.7 +/- 0.7 to 22.8 +/- 1.4 Hz (mean +/- SE, p less than 0.01) within 5 min, which was followed by a decline to the baseline value by 10 min. This effect was concentration-dependent, the maximal increase from the baseline value and the drug concentration required to produce a half-maximal effect (EC50) being 26.9 +/- 4.6% (p less than 0.01) and 3 x 10(-7) M, respectively. The U46619-induced increase in CBF was abolished by SQ29548, and TxA2 receptor antagonist, and inhibited by verapamil, a Ca(2+)-entry blocker, and H-7, a protein kinase C inhibitor. These results suggest that TxA2 stimulates ciliary motility through the activation of airway epithelial TxA2 receptors, and that this effect may be exerted from Ca(2+)-influx and protein kinase C.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

The role of radiotherapy in the treatment of primary mediastinal seminoma.

Nine patients with primary mediastinal seminoma were treated with radiotherapy. All patients achieved complete response on chest radiography. None of the three patients treated with whole mediastinal irradiation relapsed. Four of the six patients with involved-field irradiation had marginal relapses, suggesting the efficacy of the whole mediastinal irradiation.

Adolescent↗
PubMed1992

Augmentative effects of tumor necrosis factor-alpha (human, natural type) on polymorphonuclear leukocyte-derived superoxide generation induced by various stimulants.

We investigated the effects of tumor necrosis factor-alpha (human, natural type: n-TNF) on polymorphonuclear leukocyte (PMN)-derived superoxide generation by the new method of Cypridina luciferin analog-dependent chemiluminescence, which had high sensitivity and specificity to superoxide. Preincubation of PMNs with n-TNF for 3 min increased PMN-derived superoxide generation induced by phorbol myristate acetate, A23187, opsonized zymosan and N-formyl-methionyl-leucyl-phenylalanine in a concentration dependent manner (0.5-50 Japan reference units/ml of n-TNF). In addition, the enhanced PMN-derived superoxide generation by n-TNF showed a positive correlation to the preincubation time of PMNs with n-TNF (3-15 min). However, a direct incubation of PMNs with n-TNF for 1 h did not induce superoxide from PMNs without the above stimulants. The augmentative effects of n-TNF on PMN-derived superoxide generation should be useful in the PMN-mediated host defense mechanism, such as bactericidal and antitumor activity. The local concentration of n-TNF and the n-TNF-PMN contact time are considered very important in obtaining these effects more efficiently in addition to the presence of PMN-stimulants including complements, chemotactic peptides and phorbol esters.

Dose-Response Relationship, Drug↗
PubMed1992

Are plasma endotoxin levels related to burn size and prognosis?

Plasma endotoxin concentrations were determined in 42 patients with burns covering more than 20 per cent of the body surface area, using the endotoxin-specific Endospecy assay and treatment of plasma by a new method developed by ourselves. The normal endotoxin level was 9.8 pg/ml or less. In the early period after injury when no infection was present, very few patients had an endotoxin level above 9.8 pg/ml and endotoxin levels did not correlate with the area of the burns or with prognosis. However, later in the clinical course, endotoxin levels were correlated significantly with the burned area and with the prognosis.

Adolescent↗
PubMed1992

Bone scans in patients with osteoarthritis of the hip for the evaluation of bipolar hip arthroplasty: quantitative analysis using SPECT.

To establish the time-course of bone scans after bipolar hip arthroplasty (BHA) bone scanning was performed before and after surgery in 22 hips. The influence of migration of the outer head into the acetabulum on the time-course of bone scans was examined by analyzing the relationship between the uptake of radioisotope and the magnitude of migration. The bone scans were quantitatively analyzed by single photon emission computed tomography (SPECT) on the basis of the ratio of radioactivity at the acetabulum to that in the anterior superior iliac spine (ASIS). The increased radionuclide activity decreased exponentially to a baseline with time after surgery. The postoperative uptake ratio could be expressed as a function of the preoperative uptake ratio and the postoperative length of time. The regression slope representing the decreasing rate of uptake showed no significant differences between two groups divided by the magnitude of migration of the outer head. Migration of the outer head was considered not to influence the time-course of the bone scans.

Adult↗
PubMed1992

Role of leukotrienes in gastric mucosal injury induced by ischemia-reperfusion in rats.

This study was designed to clarify the role of leukotrienes (LTs) in gastric injury induced by ischemia-reperfusion in rats. Gastric lesions were produced by clamping of the celiac artery and by reoxygenation following clamping. Administration of AA-861, a lipoxygenase inhibitor, significantly inhibited the increase in the total area of the gastric erosions and the increase in thiobarbituric acid-reactive substances in the gastric mucosa. Administration of YM-638, a peptide LT antagonist, showed protective effects similar to AA-861. These results suggest that the protective effects of AA-861 and YM-638 against ischemia-reperfusion-induced gastric injury were due to their antioxidative action.

Animals↗