Biomedical subjects

M Tsuboi

Publications and source records attributed to M Tsuboi.

At least 127 records · Page 7Linked to original sources

PubMed1992

[Endoscopic surgery of airway lesions by Nd-YAG laser treatment].

Between April 1980 and November 1990, we treated 212 cases of airway lesion using an Nd-YAG laser via the fiberoptic bronchoscope. The Nd-YAG laser power output was usually 40 W (20-60 W) delivered in 2 sec. shots. The cases consisted of 98 primary lung cancer, 12 primary tracheal cancer, 53 metastatic airway lesion, 7 benign tumor, and 42 cicatricial and granulomatous lesions. The therapeutic effects of Nd-YAG laser treatment were evaluated based on alleviation of dyspnea, widening of airway, and curative vaporization for therapeutic purposes. Effectiveness was observed in 180 of a total of 212 cases (84.9%). Out of 75 emergency cases in which a lifesaving procedure was performed to widen the airway, effective results were obtained in 70 (93.3%) with dramatic improvement in condition. It was also effective in 90 of 109 cases (82.6%) in which the procedure was performed for staged (palliative) widening of airway. In 55 cases of advanced lung cancer (Stage III or IV, mainly non-small cell cancer) in which palliative widening procedure was performed, one year survival was 44%. In 13 of 18 cases (72.2%) in which the procedure was performed for curative vaporization of invasive cancer, successful results were obtained. In 7 cases of benign tumor in which vaporization was performed as a radical curative procedure, no recurrence was observed in any cases. In 53 cases of metastatic airway lesion, effective results were obtained 48 (90.6%). The primary lesions of these cases consisted of 14 cases of esophageal cancer, 9 cases of lung cancer, 7 cases of colo-rectal cancer, 7 cases of thyroid cancer, and 16 others.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchoscopy↗

PubMed1991

Substance P-induced diacylglycerol formation in rat parotid acinar cells.

The mechanisms underlying the ability of substance P, to stimulate the sn-1,2-diacylglycerol (DAG) formation were studied using rat parotid acinar cells. During a 60 s stimulation, 1 microM substance P caused a rapid rise in DAG accumulation at 5 s, whereas a low (0.1 microM) concentration of agonist did not. During long term stimulation for 30 min, DAG accumulation induced by 1 microM substance P reached near maximal levels at 5 min and remained elevated for at least 20 min. In contrast, DAG formation induced by 0.1 microM substance P exhibited a peak at 5 min, gradually declined and returned to near basal levels at 30 min. Furthermore, DAG accumulation in response to substance P at 5 and 20 min increased in a dose-dependent manner. The breakdown of both [32P]phosphatidylinositol 4-monophosphate ([32P]PIP) and [32P]phosphatidylinositol 4,5-bisphosphate ([32P]PIP2) stimulated by 1 microM substance P significantly increased from 5 to 20 min and returned to basal levels by 30 min; however, the breakdown of [32P]PIP2 was greater than that of [32P]PIP. At a low concentration of substance P, [32P]PIP2 breakdown reached maximal levels at 5 min followed by a progressive decrease and returned to basal levels at 30 min, whereas the breakdown of [32P]PIP reached maximal levels at 5 min and returned to near basal levels at 10 min. Both concentrations of substance P caused some [32P]phosphatidylinositol breakdown at 5 min. Changes in [3H]inositol trisphosphate induced by substance P were similar to those in [32P]PIP2. In addition, substance P (1 microM) did not stimulate the release of [3H]choline or [3H]ethanolamine metabolites into the medium. Substance P-induced DAG formation was not inhibited by staurosporine, a protein kinase C inhibitor. These results suggest that DAG formation caused by substance P is closely associated with the hydrolysis of phosphatidylinositides but not that of phosphatidylcholine or phosphatidylethanolamine, and is not regulated by protein kinase C-dependent mechanism(s).

Alkaloids↗

PubMed1991

Protein kinase C-dependent diacylglycerol formation is mediated via Ca2+/calmodulin in parotid cells.

The kinetics of carbachol-induced sn-1,2-diacylglycerol (DAG) formation and the underlying mechanism(s) involved in parotid acinar cells were investigated. Supramaximal concentrations of carbachol for amylase secretion (10 microM) caused a transient rise in DAG levels at 10 s. In contrast, this rapid rise was not elicited by 1 microM carbachol, which is the maximally effective concentration for amylase secretion. Carbachol (10 microM) also increased DAG levels linearly up to 20 min, which were sustained for up to a further 10 min. DAG formation stimulated by 1 microM carbachol was biphasic; the first peak was observed after 5 min and the second after 20 min. DAG formation induced by 0.01-0.1 microM carbachol was concentration-dependent and monophasic, peaking at 5 min. The second peak evoked by carbachol was partly inhibited by Ca2+ deprivation from the extracellular space, whereas the first peak was not. Similar results were obtained in experiments using Ca2+ antagonists such as verapamil and LaCl3. The protein kinase C inhibitors, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) and staurosporine, and a calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), significantly inhibited the second DAG peak produced by 1 microM carbachol, but did not alter the first peak. The degree of inhibition of the second peak by these antagonists was comparable. Furthermore, the inhibitory effect of staurosporine and W-7 was concentration-dependent. The A23187-induced accumulation of DAG also was abolished by both staurosporine and W-7. These data indicate that a protein kinase C-dependent mechanism(s) is involved in mediating the second DAG accumulation peak induced by 1 microM carbachol and is mainly regulated by the Ca(2+)-calmodulin complex.

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

PubMed1991

Effects of the mammalian lignan, 2,3-dibenzyl-butane-1,4-diol, on contraction and Ca2+ mobilization induced by noradrenaline in rat aorta.

1. In rat aorta, 2,3-dibenzylbutane-1,4-diol (DBB) inhibited noradrenaline (NA)-induced contraction in a concentration-dependent manner. The inhibitory effect of DBB was observed in verapamil-pretreated muscle, and did not differ from that in the high K+ solution containing verapamil (1.0 microM). 2. DBB inhibited not only contraction, but [Ca2+]i elevation induced by NA (10 microM) with the same potency. 3. The inhibitory effect of DBB on NA-induced contraction was reversed by methylene blue (3.2 microM) and enhanced by M&B 22,948 (10 microM). 4. DBB (100 microM) alone increased cyclic GMP levels. This effect was attenuated by methylene blue (3.2 microM) and augmented by M&B 22,948 (10 microM). 5. From these results, the inhibitory effects of DBB on NA-induced contraction in rat aorta may be caused by an increase of cyclic GMP levels.

Animals↗

PubMed1991

In vivo adaptive control of beta-receptors and adenylate cyclase during short-term heat exposure in rat parotid glands.

1. Adaptation of beta-adrenergic receptors (beta-AR) and adenylate cyclase (AC) in rat parotid glands during short-term heat exposure (33 degrees C) were studied. 2. Heat exposure reduced AC activity in response to isoproterenol (IPR). 3. The number of beta-AR on the cell surface significantly increased after 24 hr but returned to control level after 48 hr. 4. IPR-induced [3H]GDP release was significantly reduced throughout exposure. 5. The data suggest that the major factor which results in the desensitization of AC during short-term heat exposure is a blunted coupling between beta-AR and GTP binding protein(s).

Adaptation, Physiological↗

PubMed1991

The present status of bronchoscopic Nd:YAG laser.

In Japan, the first bronchoscopic Nd:YAG laser applied clinically was performed in our institute 10 years ago, and based on this decade of experience, the indications, effectiveness, and limitations were studied. Between 1980 and 1989, a total of 202 cases were treated by Nd:YAG laser in our institute. Among them, 94 (46.5%) cases were primary lung cancers, 10 (5.0%) cases were primary tracheal malignancies, 56 (27.7%) cases were metastatic tracheal tumors, 6 (3.0%) cases were benign tracheal tumors, and 36 (17.8%) cases were nontumorous tracheal lesions. The indications for Nd:YAG laser therapy were defined as emergency widening of airway, curative treatment, reduction of tumor size, nontumorous benign lesions, and hemostasis. The desired therapeutic effects were obtained in 55/58 (94.8%) for emergency airway widening, 22/27 (81.5%) for curative treatment, 69/88 (78.4%) for reduction of tumor size, and 48/68 (70.6%) for nontumorous benign lesions. While performing Nd:YAG laser treatment, some limitations, such as poor residual pulmonary function, tumor size, tumor depth, cartilage structure, granulation, and stricture length, were encountered. Since bronchoscopic Nd:YAG laser treatment has become a well-established therapeutic modality for tracheobroncheal lesions, areas to be addressed in the future are the training of bronchoscopic laser therapists and research on the extension of applications. To increase the range of clinical applications, it is hoped that makers of laser systems will provide tunable wavelength machines at reduced cost.

Bronchoscopes↗

PubMed1991

Enhanced coupling of adenylate cyclase to lipolysis in permeabilized adipocytes from trained rats.

Digitonin-permeabilized adipocytes were used to study the coupling of adenylate cyclase (AC) to lipolysis in exercise-trained rats. Isoproterenol-(IPR) stimulated lipolysis in permeabilized cells was significantly greater in trained than in control rats. Under essentially identical conditions, the dose-response curve for IPR stimulation of AC activity in the absence of 3-isobutyl-1-methylxanthine was similar in trained and control rats. However, the potency of stimulation by IPR as a percentage of the basal level was greater in trained rats. AC activity and lipolysis in the presence of 3-isobutyl-1-methylxanthine were also significantly greater in trained than in control rats. Least-squares analysis by plotting the log AC vs. lipolysis values showed that the regression coefficient was about three-fold greater in trained than in control rats. The concentration of endogenous adenosine 3',5'-cyclic monophosphate (cAMP) needed to produce a half-maximal lipolytic response was 18.58 and 10.81 pmol.min-1.10(6) cells-1 in control and trained rats, respectively. Thus a positive relationship existed between lipolysis and AC activity, with a tighter coupling in trained rats. Lipolysis in response to exogenous cAMP tended to be greater in trained than in control rats, and the difference was statistically significant for 50 microM and 10 mM cAMP. Our finding support the concept that the major mechanism of enhanced lipolysis in trained rats was an increase in the activity of enzymatic step(s) distal to cAMP.

1-Methyl-3-isobutylxanthine↗

PubMed1991

Effects of combination therapy with low-dose aspirin and warfarin on platelet functions after heart valve replacement.

To evaluate the efficacy and safety of combination therapy with aspirin and warfarin for preventing the development of thromboembolism, we compared the effects of low-dose aspirin (81 mg/day) on platelet functions to those of ticlopidine (300 mg/day) in heart valve replacement patients. Experiments were performed in two groups; the first group within 1 month after operation (the unstable period) and the second group between 3 months and 3 years after operation (the stable period). At the stable period, low-dose aspirin inhibited platelet aggregation induced by ADP, collagen, or arachidonic acid, and suppressed the increase in intracellular Ca2+ concentration [( Ca2+]i) induced by thrombin significantly. On the other hand, ticlopidine inhibited platelet aggregation induced by ADP or collagen, but did not suppress arachidonic acid-induced aggregation and the thrombin-induced [Ca2+]i increase. At the unstable period, the combination therapy of low-dose aspirin plus warfarin did not prolong the bleeding time compared to ticlopidine plus warfarin. And low-dose aspirin inhibited platelet aggregation induced by ADP, collagen or epinephrine, and especially blocked arachidonic acid-induced aggregation. Ticlopidine inhibited ADP-, collagen- or U-46619-induced aggregation, but did not affect on the increase in [Ca2+]i induced by thrombin. From the results in this study, we suggest that the combination therapy with low-dose aspirin (81 mg/day) and warfarin is safe as an antithrombotic medication in heart valve replacement, and results in the inhibition of platelet functions without any side effect calling for special mention at the early unstable period after operation.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed1990

Priming effect of 2,3-dibenzylbutane-1,4-diol (mammalian lignan) on superoxide production in human neutrophils.

We investigated the effect of 2,3-dibenzylbutane-1,4-diol (DBB), a mammalian lignan, on superoxide production and [Ca2+]i mobilization in human neutrophils. DBB did not generate superoxide production by itself, but enhanced the FMLP or A23187-induced superoxide production in a dose dependent manner. DBB did not influence the OAG-induced superoxide production. The priming effect of DBB was inhibited by W-7 or trifluoroperazine, but not by H-7 or staurosporine. And the priming effect of DBB was observed in the presence or absence of extracellular Ca2+. DBB enhanced the low dose FMLP-induced [Ca2+]i mobilization. These results suggest that the priming effect of DBB in human neutrophils may be caused by the activation of the calcium-calmodulin pathway but not the protein kinase pathway.

Alkaloids↗

PubMed1990

A porphyrin-DNA exciplex: resonance Raman spectra of electronically excited Cu(TMpy-P4) bound to poly(dA-dT).poly(dA-dT).

The resonance Raman spectra of water-soluble porphyrins, Cu(TMpy-P4) and Ni(TMpy-P4), and their mixtures with DNA, Poly(dG-dC).Poly(dG-dC), and Poly(dA-dT).Poly(dA-dT) were measured using 426 nm pulsed laser excitation (and 556 nm for some applications). At high laser power, the solution of Cu(TMpy-P4) mixed with DNA or Poly(dA-dT).Poly(dA-dT) exhibits new bands at 1550 and 1349 cm-1 that are not observed for Cu(TMpy-P4) alone or for Cu(TMpy-P4) mixed with Poly(dG-dC).Poly(dG-dC). These extra bands do not appear when the resonance Raman spectra are measured by a cw laser or by a pulsed laser with low power. Similar mixtures of M(TMpy-P4) (where M = Ni, Zn, Co, Mn, and H2) with these nucleic acids exhibit no such bands even by high power pulsed laser excitation. We attribute the new resonance Raman bands to an electronically excited Cu(TMpy-P4), stabilized by forming an exciplex with the A-T site of the nucleic acid. The minimum lifetime value of such an exciplex was estimated to be on the order of 10 ps.

Copper↗

PubMed1990

Hypotensive effects on spontaneously hypertensive rats and antifungal activity on various species of Fusarium oxysporum of diethylstilbestrol-related compounds.

The diethylstilbestrol-related compounds 3,3'-dihydroxy-alpha, beta-diethyldiphenylethane (I), diethylstilbestrol (II) and hexestrol (III) showed hypotensive effects on spontaneously hypertensive rats (SHR) and antifungal activities against all Fusarium oxysporum sp. tested. As previously reported, I had strong hypotensive action on normotensive rats at the dose of 10 mg/kg, while II and III showed weak hypotensive effects on these rats at the same dose. In this work, all three compounds also had hypotensive actions on SHR at the same dose. I showed the strongest hypotensive effect (-80.0 +/- 5.0 mmHg, 10 mg/kg, i.v.) on both SHR and normotensive rats. The three compounds also had antifungal activities against five kinds of Fusarium oxysporum sp. tested. Especially, II strongly inhibited the growth of Fusarium oxysporum f. sp. raphani IFO-9972 (minimum inhibitory concentration (MIC): 1.0 micrograms/ml).

Animals↗

PubMed1990

Biological activities of racemomycin-B, beta-lysine rich streptothricin antibiotic, the main component of Streptomyces lavendulae OP-2.

Racemomycin-B (RM-B), the main component of Streptomyces lavendulae OP-2 which is the basis of 50% of the antibiotics produced, is a streptothricin antibiotic which contains three beta-lysine moieties in the molecule. RM-B had antimicrobial activity against plant-pathogenic microorganisms and growth-inhibitory activity against the root of Brassica rapa L. at the concentration of 50 ppm. It strongly inhibited the growth of Pseudomonas syringae pv. tabaci IFO-3508 (minimum inhibitory concentration (MIC): 0.4 microgram/ml), and also showed antifungal activity against six kinds of Fusarium oxysporum species (MIC: 0.1-2.0 micrograms/ml). The antimicrobial activity of RM-B was much stronger than those of RM-A and -C which contain, respectively, one and two beta-lysine moieties in their molecules. The above activities of RM-A, -C and -B were thus in the order of -B greater than -C greater than -A: namely, the biological activity of racemomycin compounds tended to be stronger with increase in the number of beta-lysine moieties in the molecule.

Fusarium↗

PubMed1990

Inhibitory effect of 2,3-dibenzylbutane-1,4-diol; a mammalian lignan, on the CA2+ channel in rabbit femoral artery.

2,3-Dibenzylbutane-1,4-diol (DBB) is a mammalian lignan derived from human urine. To investigate the pharmacological actions of mammalian lignans, the effects of DBB on high K(+)-induced contraction in rabbit femoral artery were studied. High K+ induced a transient contraction followed by sustained contraction, and both depended on extracellular Ca2+. DBB inhibited transient contraction as well as sustained contraction. Verapamil or nifedipine inhibited sustained contraction more effectively than transient contraction. DBB inhibited the transient contraction remaining in the verapamil- or the nifedipine-pretreated preparation in a concentration-dependent manner. Moreover, DBB inhibited sustained contraction elicited by Bay K 8644 (Ca2+ channel activator). These results indicate that DBB effects not only the sensitive Ca2+ channels but also the insensitive channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1990

Diacylglycerol accumulation is involved in the potentiating effect of A23187 on carbachol-stimulated amylase secretion from parotid gland.

We studied the role of sn-1, 2-diacylglycerol (DAG) accumulation in the potentiating effect of A23187 on carbachol (CCh)-stimulated amylase secretion from rat parotid acinar cells. A23187 (0.1 microM) linearly increased DAG accumulation with time for at least 30 min. At concentrations higher or lower than 0.1 microM, DAG levels increased for up to 20 min, but declined at 30 min. Dose-response curve for DAG accumulation induced by A23187 was similar to that for amylase secretion. A23187 augmented CCh-stimulated DAG accumulation and amylase secretion. These results suggest that DAG accumulation is involved in the potentiating effect of A23187 on CCh-stimulated amylase secretion.

Amylases↗

PubMed1990

A protein kinase C-dependent mechanism(s) is involved in atropine-resistant accumulation of diacylglycerol in rat parotid gland.

We investigated the atropine-resistant accumulation of sn-1,2-diacylglycerol (DAG) on stimulation of 1 microM carbachol (CCh) in parotid acinar cells. CCh-induced DAG accumulation was biphasic, peaking at 5 and 20 min. Atropine inhibited two peaks in a dose-dependent manner, but the first peak was inhibited much more than the second one. Atropine (10 microM) completely inhibited both DAG accumulation and the breakdown of phosphatidylinositol 4-monophosphate and 4,5-bisphosphate (PIP2) 5 min after stimulation with CCh. In contrast, the breakdown of PIP2 at 20 min was completely inhibited by 10 microM atropine, but DAG accumulation was not. This atropine-resistant component at 20 min is significantly inhibited by staurosporine, a protein kinase C inhibitor. These results suggest that atropine-resistant accumulation of DAG at 20 min derives directly from other lipids rather than phosphoinositides and is regulated by a protein kinase C-dependent mechanism(s).

Alkaloids↗

PubMed1990

[A case report of fibromatosis originating from the right anterior scalene muscle].

Fibromatosis is rare and locally invasive tumor arising from musculoaponeurotic tissue, and also has a high postoperative recurrence rate. So, we must perform wide resection of the tumor and surrounding tissue. A case of fibromatosis originating from the right anterior scalene muscle was reported. A 31-year-old female in whom cervical fibromatosis had been pointed out by her home doctor, was referred to our hospital for treatment. CT scan, MRI and angiography showed that the tumor developed from the cervical lesion to the upper thoracic and invaded the right subclavian artery. The tumor originating from right anterior scalene muscle was found at operation. The combined resection consisted of the right anterior salene muscle with tumor, phrenic nerve, subclavian artery and vein, and chest, well including the first and second rib and clavicular bone, because of wide invasion of tumor to surrounding organs. Reconstruction of the subclavian artery and vein was performed by PTFE vascular prostheses. The postoperative course was uneventful, she is now in good health 8 months after operation with good blood flow via the reconstructed vessels confirmed by angiography, without any sign of recurrence.

Adult↗

PubMed1989

A DNA sequence in Saccharomyces exiguus is homologous with the HO gene of Saccharomyces cerevisiae.

The DNA of Saccharomyces exiguus was analyzed by Southern hybridization using cloned MATa, MAT alpha, and HO genes of Saccharomyces cerevisiae as probes. It was shown that S. exiguus has a DNA sequence homologous with the HO gene of S. cerevisiae and that this DNA sequence is on a chromosome of about 940 kb of DNA in S. exiguus. However, there is no DNA sequence in S. exiguus that is homologous with the MAT genes of S. cerevisiae.

Base Sequence↗

PubMed1989

An acute exercise-induced translocation of beta-adrenergic receptors in rat myocardium.

The effect of acute exercise (treadmill running) on rat myocardium beta-adrenergic receptors (beta-AR) was studied. beta-AR was identified in purified sarcolemmal membrane fractions and light vesicle fractions. In control hearts, the number of beta-AR was 21.25 +/- 2.25 and 20.89 +/- 2.89 fmol/mg protein (mean +/- SE) in sarcolemmal membranes and light vesicles, respectively. Immediately after a single bout of dynamic exercise, about 35% of beta-AR was transferred from light vesicles to sarcolemmal membranes (p less than 0.05); concomitantly, isoproterenol-stimulated adenylate cyclase activity also significantly increased in sarcolemmal membranes (p less than 0.05). These results suggest that acute exercise provokes the translocation of beta-AR from a presumably intracellular site (light vesicles) to functional membrane fractions (sarcolemmal membranes) in rat myocardium.

Adenylyl Cyclases↗