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S Houjou

Publications and source records attributed to S Houjou.

6 recordsLinked to original sources
PubMed1996

Effect of cetirizine on antigen-induced tracheal contraction of passively sensitized guinea pigs.

BACKGROUND: Cetirizine dihydrochloride (cetirizine), a potent histamine H1-receptor antagonist, has been developed as an anti-allergy drug. OBJECT: The anti-allergic effects and mechanism of cetirizine were studied using in vitro assay systems. METHODS: We investigated the effect of cetirizine on antigen-induced contractions of isolated tracheal strips and on chemical mediator release from antigen-stimulated lung chips taken from passively sensitized guinea pigs. We examined the antigen-induced mobilization of Ca2+ in MC/9 mast cells sensitized with IgE. RESULTS: Cetirizine inhibited the antigen-induced contraction of isolated guinea-pig trachea concentration dependently. Pyrilamine, another histamine H1-receptor antagonist, delayed the response but did not change the maximum amplitude. Cetirizine at the concentration of 3 microM also inhibited the antigen-induced release of histamine, leukotriene D4, and leukotriene E4 from guinea pig lung chips. Furthermore, it inhibited the antigen-induced Ca2+ increase in MC/9 mast cells, whereas pyrilamine did not. CONCLUSION: These findings suggest that one anti-allergic mechanism of cetirizine may inhibit mediator release which is, at least partially, mediated by a decrease in the transient Ca2+ influx in mast cells.

Animals↗
PubMed1996

Allergic responses reduce the relaxant effect of beta-agonists but not potassium channel openers in guinea-pig isolated trachea.

This study was conducted to determine whether the relaxant effect of adenosine triphosphate (ATP)-sensitive potassium channel (KATP) openers on airway smooth muscle are reduced during the hyporesponsiveness of beta-adrenergic receptors. Isometric tension was measured and dose-response curves were constructed for levcromakalim (a KATP opener), Y-26763 (another KATP opener), isoprenaline and theophylline in guinea-pig isolated trachea that was challenged with ovalbumin or pretreated in vitro with either isoprenaline or the KATP openers. Antigen challenge in vitro significantly reduced the potency but not the efficacy of isoprenaline in tracheal strips from actively sensitized guinea-pigs. The concentration of drug that produced a half-maximum inhibition (IC50) was 0.014 +/- 0.004 microM in the challenge group versus 0.006 +/- 0.001 microM in the control group (p < 0.05; n = 9). The IC50 of levcromakalim (1.73 +/- 0.17 microM; n = 6) and of theophylline (110 +/- 3.1 microM; n = 6) were unaffected. Exposure to 4 microM isoprenaline for 30 min evoked beta-adrenergic hyporesponsiveness: the IC50 of isoprenaline rose significantly from 0.010 +/- 0.001 to 0.017 +/- 0.002 microM (p < 0.01; n = 6). No effect was observed on the relaxant actions of levcromakalim and theophylline. In contrast, prior incubation with either levcromakalim or Y-26763 (300 microM for 30 min) significantly reduced the subsequent potency and efficacy of levcromakalim, but did not alter the effects of isoprenaline and theophylline. We conclude that the relaxant effect of the adenosine triphosphate-sensitive potassium channel openers was independent of beta-adrenergic hyporesponsiveness in airway smooth muscle of guinea-pigs.

Adrenergic beta-Agonists↗
PubMed1994

Diabetic scleredema and scleroderma-like changes in a patient with maturity onset type diabetes of young people.

A 21-year-old housewife with maturity onset type diabetes of young people developed scleredema diabeticorum, scleroderma-like skin thickness on forearms and dorsum of hands, digital sclerosis and cheiroarthropathy. She had diabetes mellitus since the age of 11 years. Her grandfather on the mother's side, her mother and 3 of 5 her mother's brothers and sisters have diabetes mellitus. Blood glucose was 295 mg/dl. Urinary glucose was 5.3 g/day. Nail fold capillary microscopy revealed a progressive systemic sclerosis pattern. Histologically, hematoxylin and eosin sections from back and forearm skin demonstrated broad collagen bundles separated by widened clear spaces throughout the thickened dermis.

Adult↗
PubMed1994

[Staggered intensive chemotherapy using arbekacin, fosfomycin and ceftazidime on polymicrobial infections involving MRSA].

Bacteriological and clinical studies were carried out on staggered intensive chemotherapy regimen for methicillin-resistant Staphylococcus aureus (MRSA) infections combined with Gram-negative opportunistic pathogens as polymicrobial infections. The regimen consisted of administering ceftazidime (CAZ) 30 minutes after infusion of arbekacin (ABK) and a bolus injection of fosfomycin (FOM). The combination of these drugs strongly inhibited the growth of MRSA and Pseudomonas aeruginosa. By this combination treatment, both of MRSA and P. aeruginosa in mixed culture became more susceptible to killing by macrophages. We evaluated the clinical efficacy and safety of combination of ABK, FOM and CAZ in the treatment of 15 patients with MRSA infections. The total efficacy rate was 80.0% and the bacterial eradication rate of MRSA was 60.0%. It is considered that staggered intensive chemotherapy with ABK, FOM and CAZ is useful for such polymicrobial infections involving MRSA.

Aged↗
PubMed1992

Evaluation of airway smooth muscle contractions in vitro by high-frequency ultrasonic imaging.

To visualize ASM contraction in vitro, we measured changes in cross-sectional area and inner circumference of isolated porcine and human bronchi in response to acetylcholine or carbamylcholine chloride (Carbachol) using high-frequency ultrasound. A mechanical ultrasonic catheter (20 MHz; diameter, 1.7 mm; echo element, 1 mm2) demonstrated three histologic layers (mucosa, cartilage and adventitia) and allowed measurement of dose-dependent contraction of porcine bronchi over time. Acetylcholine (10(-4)M) significantly decreased the cross-sectional area by 17 +/- 2.85 percent but did not change the circumference. The mean initial value for area was 0.6 +/- 0.08 cm2 and for circumference was 3.0 +/- 0.24 cm (n = 5). The EC50 of acetylcholine was 1.5 x 10(-8) M. Carbachol (10(-4)M)-induced contractions of human bronchi were also observed under the same conditions. In conclusion, high-frequency ultrasonic imaging can be used to study the morphology of ASM contractions in vitro, providing valuable information on the natural dynamics of ASM.

Acetylcholine↗