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Biomedical subjects

S Itabashi

Publications and source records attributed to S Itabashi.

26 records · Page 2Linked to original sources
PubMed1990

Inhibitory actions of prostaglandin E1 on non-adrenergic non-cholinergic contraction in guinea-pig bronchi.

We have investigated the effect of prostaglandin E1 (PGE1) on non-adrenergic, non-cholinergic (NANC) contraction in guinea-pig bronchial strips. PGE1 (10 nM to 10 microM) did not alter baseline tension but reduced NANC contractions induced by electrical field stimulation (EFS) in a concentration-dependent fashion (-log EC50 was 6.60 +/- 0.10 M and maximum inhibition was 88.7 +/- 2.9%). PGE1 (greater than 0.3 microM) also reduced the contraction induced by substance P (1 microM). Removal of epithelium did not alter the effects of PGE1 on NANC contraction. These results suggest that PGE1 exerts both pre- and post-junctional inhibitory actions on NANC contraction.

Alprostadil↗
PubMed1990

Nonadrenergic inhibitory nerves attenuate neurally mediated contraction in cat bronchi.

Effects of nonadrenergic and noncholinergic (NANC) inhibitory nerves on cholinergic neurotransmission were examined in isolated bronchial segments from cats in the presence of propranolol (10(-6) M) and indomethacin (10(-6) M) by use of electrical field stimulation (EFS) techniques. EFS caused contraction alone in tissues at the baseline tension and biphasic responses (contraction and relaxation) in tissues precontracted with 5-hydroxytryptamine. Contraction was abolished by atropine (10(-6) M), and relaxation was abolished by tetrodotoxin (10(-6) M). At the baseline tension, EFS at frequencies greater than 10 Hz inhibited the subsequent (4 min later) contraction induced by EFS at 1-5 Hz. EFS-induced inhibition was stimulus frequency dependent and reached maximum at 20 Hz. However, EFS at 20 Hz did not inhibit the subsequent contractile response to acetylcholine (10(-7) to 10(-3) M). Exogenously applied vasoactive intestinal peptide mimicked EFS-induced inhibitory effects, but substance P and calcitonin gene-related peptide did not. The inhibitory effect of EFS at 20 Hz was not altered by pyrilamine, cimetidine, naloxone, methysergide, phentolamine, BW755C, AF-DX 116, or removal of epithelium. These results imply that the NANC transmitter acts via presynaptic cholinergic receptors.

Animals↗
PubMed1990

Allergic sensitization in elderly patients with chronic obstructive pulmonary disease.

To study whether allergic sensitization occurs in elderly patients with chronic pulmonary obstructive disease (COPD), we examined serum IgE and skin test reactivity to allergens in three age-matched groups of normal subjects, and in patients with COPD and bronchial asthma (BA). Serum IgE was significantly higher in patients with COPD and BA than in normal subjects (p less than 0.05), and patients with COPD showed serum IgE levels as high as those of patients with BA. However, the skin test scores were significantly higher in patients with BA than in normal subjects and patients with COPD (p less than 0.05). Neither serum IgE nor skin test score significantly correlated with FEV1%, PaO2, PaCO2 or Brinkman's Index in any group (p greater than 0.20). These results suggest that allergic sensitization occurs in elderly patients with COPD and that symptoms associated with COPD may be partly due to allergic inflammation.

Asthma↗
PubMed1990

Eosinophil supernatant causes hyperresponsiveness of airway smooth muscle in guinea pig trachea.

To study the role of eosinophils in airway hyperresponsiveness, we studied the effect of supernatant obtained from activated eosinophils on the responses of isolated guinea pig tracheal smooth muscle segments to histamine. Eosinophils obtained from guinea pig peritoneal fluid were purified and activated with Ca2+ ionophore A23187 using a two-stage reaction. Supernatant obtained from different eosinophil cell numbers (3 x 10(5) to 10(7) cells) did not alter resting tension but potentiated the contractile response to histamine in a cell number-dependent fashion. Thus, at a cell number of 10(7), the supernatant decreased the mean (+/- SE) log histamine concentration producing 50% of maximum contraction significantly from a control value of -5.62 +/- 0.10 to -5.99 +/- 0.07 M (p less than 0.05). The potentiating effect of the supernatant (10(7) cells) was not altered by either removal of tracheal epithelium or by pretreatment with indomethacin when cells were activated. However, pretreatment with AA 861 completely inhibited the supernatant (10(7) cells)-induced potentiating effect associated with inhibition of leukotriene C4, D4, and E4 release in the supernatant. The concentrations of exogenous authentic leukotrienes chosen to match concentrations in the supernatant mimicked the supernatant-induced potentiating response to histamine. These results suggest that leukotrienes released from eosinophils cause hyperresponsiveness of airway smooth muscle in vitro.

Animals↗
PubMed1990

Permanent brain damage possibly caused by theophylline in two elderly patients with airway obstruction.

Two aged patients with bronchial asthma and chronic obstructive pulmonary disease who suffered convulsions that resulted in permanent brain damage during treatment with the recommended therapeutic dose of theophylline are presented here. A dose or concentration of theophylline lower than the recommended one should be considered in the treatment of some aged patients with pulmonary obstructive disease.

Aged↗
PubMed1990

Prolonged hypoxemia after 10 min walking exercise in aged patients with chronic obstructive pulmonary disease.

Although the behavior and factors of exercise tolerance have been studied during exercise in patients with chronic obstructive pulmonary disease (COPD), little attention has been paid to the after-effects of such activity. Arterial oxygen saturation (SaO2) was monitored during and after a 10 min walking exercise in aged patients with COPD. Neither baseline SaO2 nor mean SaO2 during exercise correlated to the 10 min walking distance. However, the recovery time of SaO2 to the baseline value shows significant correlation to the 10 min walking distance. Careful attention should be paid to prolonged hypoxemia after exercise in severe cases of COPD.

Aged↗