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C Ohkawa

Publications and source records attributed to C Ohkawa.

6 recordsLinked to original sources
PubMed1999

Histamine H1 receptor and reactivity of the nasal mucosa in sensitized guinea pigs.

OBJECTIVE: Nasal Hypersensitivity to histamine is higher in allergic patients than that in normal control, suggesting that affinity and/or density of H1 receptors in nasal mucosa may be increased in patients with allergic rhinitis. The purpose in this study is to examine the correlation between the hyperresponsiveness and number of histamine H1 receptors in guinea pig nasal mucosa. METHODS: Guinea pigs were sensitized by DNP-Ascaris antigen. To block histamine H1 receptors, ketotifen was used and the number of receptors was counted by receptor binding assay technique. These data were compared with nasal airway volume (VOL) assessed by acoustic rhinometry of the same animals to know whether the number of H1 receptors is correlated to the nasal responsiveness to the antigen, or not. Eighty animals were divided into five groups which are composed of nonsensitized and sensitized group pretreated with saline, 0.1, 1.0 and 10 mg/kg of ketotifen, respectively. RESULTS: The number of H1 receptors (Bmax) was significantly increased in sensitized group compared with that in control. It decreased dose dependently by pretreatment of ketotifen. The percent change of VOL showed - 31.1 +/- 4.1% at 10 min and - 42.9 +/- 4.1% at 30 min after antigen challenge in sensitized animals. This was dose dependently inhibited by ketotifen. There was a highly inverse correlation between VOL and Bmax (r = -0.708, P< 0.0001). CONCLUSION: These results suggest that sensitization increases the number of histamine H1 receptor, and that increased number of H1 receptor in nasal mucosa in sensitized guinea pigs may be one of the causes of nasal hyperresponsiveness to antigen.

Administration, Oral↗
PubMed1998

Nasal passage patency in patients with allergic rhinitis measured by acoustic rhinometry: nasal responses after allergen and histamine provocation.

We investigated nasal passage patency after allergen and histamine provocation in patients with allergic rhinitis by acoustic rhinometry. In total, 75 outpatients with allergic rhinitis were studied. The threshold of nasal hypersensitivity to histamine was measured by the 10 microliters instillation of serial 10-fold dilution in the ipsilateral nasal cavity. Nasal provocation testing to specific antigen was applied to the anterior part of inferior turbinate in bilateral sides in sitting position. Measurement of nasal patency by acoustic rhinometry was repeated three times in each nasal cavity. The minimal cross-sectional area and total volume of nasal cavity were measured in an individual subject. The minimal cross-sectional area and total volume in the histamine challenged-side significantly decreased on the 10(-2), 10(-1), 10(-0) of end point, and up to 30 min after challenge with the threshold dose, but not in the unchallenged side. This means acoustic reflection technique is sensitive at least 100-fold in comparison with classical method like findings by anterior rhinoscopy and symptom scores. Nasal passage patency after bilateral allergen provocation showed predominant in the unilateral side, suggesting the cross over-reflex effects. It was concluded that acoustic rhinometry is one of the highly quantitative and sensitive method which can observe the change of nasal congestion.

Adolescent↗
PubMed1994

[The evaluation of hyposensitization with house dust in patients with nasal allergy to house dust-mite].

We evaluated the clinical and pathophysiological efficacy of hyposensitization with house dust extracts to perennial nasal allergy. Fifty-one patients with allergic perennial rhinitis completed 5 months to 15 years with a mean of 2.4 years course of hyposensitization treatment with house dust extracts, and analyzed clinical symptoms, nasal provocation testing, nasal hypersensitivity to histamine, mast cells and eosinophils in nasal scraping, specific IgG and IgG4 antibody in serum, and blood eosinophils and basophils in relation to therapeutic duration. The improvement in nasal symptoms was found in 74.1% in adults and 66.7% in child and the continuation of hyposensitization with house dust extracts for a half to one year showed significant improvement of clinical symptoms. In objective examination, nasal provocation testing, nasal hypersensitivity to histamine, the number of mast cells and eosinophils in nasal scraping, and blood basophils showed significant improvement at 6 to 12 months the same as clinical symptoms. These findings suggest that the continuation of hyposensitization with house dust extracts is recommendable as a basic treatment against perennial nasal allergy.

Adolescent↗
PubMed1994

[The evaluation of hyposensitization with sugi pollen extracts in patients with nasal allergy to Japanese sugi pollen].

We evaluated the clinical and pathophysiological efficacy of hyposensitization with Japanese sugi pollen extracts to sugi pollinosis. Twenty patients with Japanese cedar pollinosis received hyposensitization with Japanese cedar pollen extracts for one to 15 years with a mean of 9.5 years were compared with 18 patients without hyposensitization. The improvement of nasal symptoms was not found in patients with hyposensitization of sugi pollen extracts compared with patients with non-hyposensitization, but the number of mast cells in nasal scraping, nasal hypersensitivity to histamine, and specific sugi IgG4 antibody in serum was improved significantly compared with non-hyposensitization group. These findings suggest that the continuation of hyposensitization with sugi pollen extracts is recommendable as a basic treatment against seasonal nasal allergy.

Adult↗
PubMedDate not supplied

Acoustic rhinometry evaluation of nasal response to histamine and antigen in guinea pigs.

The effects of antigen and histamine on the changes of nasal passage patency in 112 guinea pigs with or without allergic rhinitis were evaluated by acoustic rhinometry. The percent change of volume from the nostril to 2 cm into the nasal cavity showed significant reduction of 31.10 +/- 4.11% at 10 minutes and 31.10 +/- 4.11% at 30 minutes after antigen challenge in sensitized guinea pigs. The pretreatment with ketotifen, an H1-histamine receptor antagonist as well as mast cell stabilizing drug, blocked dose-dependently the effects of antigen on those changes in volume. Furthermore, instillation of 10(4) micrograms/mL histamine reduced significantly nasal passage patency to 33.77 +/- 4.63% at 10 minutes and 42.76 +/- 3.32% at 30 minutes after challenge compared with that before challenge and ketotifen inhibited the effects of histamine, which indicated that histamine is an important mediator of allergic upper airway responses in guinea pigs. These results show that acoustic rhinometry is a useful technique to assess the nasal blockade in allergic guinea pigs.

Acoustics↗