Plasma diamine oxidase activity in asthmatic children

Histamine plays an important role in the development of asthmatic symptoms. Diamine oxidase (DAO histaminase), which inactivates histamine, is located in the intestine and kidney and is released into plasma. Plasma DAO activity in asthmatic children was measured by a recently developed high performance liquid chromatographic method using histamine as the DAO substrate. Diamine oxidase activity was higher in severely asthmatic children than in those with mild asthma. A time course study during the acute exacerbation phase revealed that DAO activity rose during acute asthmatic attacks and then decreased gradually over several days. Although the mechanisms of plasma DAO activity increase during acute asthmatic attacks could not be explained, data showed that plasma DAO activity is an important index of histamine metabolism in asthmatics and may relate to some mechanisms of acute exacerbation of airway inflammation. Consequently, fluctuations in plasma DAO can be used as one of various indices of instability in management of asthma

Characteristics of regional cerebral oxygen saturation levels in patients with out-of-hospital cardiac arrest with or without return of spontaneous circulation: A prospective observational multicentre study.

[Aim] Our study aimed at filling the fundamental knowledge gap on the characteristics of regional brain oxygen saturation (rSO2) levels in out-of-hospital cardiac arrest (OHCA) patients with or without return of spontaneous circulation (ROSC) upon arrival at the hospital for estimating the quality of cardiopulmonary resuscitation and neurological prognostication in these patients. [Methods] We enrolled 1921 OHCA patients from the Japan – Prediction of Neurological Outcomes in Patients Post-cardiac Arrest Registry and measured their rSO2 immediately upon arrival at the hospital by near-infrared spectroscopy using two independent forehead probes (right and left). We also assessed the percentage of patients with a good neurological outcome (defined as cerebral performance categories 1 or 2) 90 days post cardiac arrest. [Results] After 90 days, 79 (4%) patients had good neurological outcomes and a median lower rSO2 level of 15% (15–20%). Compared to patients without ROSC upon arrival at the hospital, those with ROSC had significantly higher rSO2 levels (56% [39–65%] vs. 15% [15–17%], respectively; P < 0.01), and significantly correlated right- and left-sided regional brain oxygen saturation levels (R = 0.94 vs. 0.66, respectively). In both groups, the percentage of patients with a good 90-day neurological outcome increased significantly in proportion to their rSO2 levels upon arrival at the hospital (P < 0.01). [Conclusion] Our data indicate that measuring rSO2 levels might be effective for both monitoring the quality of resuscitation and neurological prognostication in patients with OHCA