Nickel Sensitivity in Asthma Patients

Nickel sulphate frequently causes allergic contact dermatitis; less known effects are nasal inflammation (rhinitis) and bronchial asthma. In this study, we aimed to find if there is a relationship between asthma and nickel sensitivity. Asthmatic patient, non-asthmatic atopic, and healthy control groups were patch tested with nickel sulphate. Nickel sensitivity was more prevalent in the asthmatic patient group compared to the non-asthmatic atopic and healthy control groups.     

Allergic contact dermatitis from 1,6-diisocyanatohexane in an anti-pill finish

We report an outbreak of occupational allergic contact dermatitis from 1,6-diisocyanatohexane (old name hexamethylene diisocyanate or HDI), in the anti-pill finish Evafanol AS-1, in 2 clothing factories. The 19 operatives from 2 dressmaking mills all complained of work-related dermatitis. 5 of the subjects had positive patch tests to the fabric with which they were working, and when all 19 were patch tested to Evafanol AS-1 (1% aq.), 11 were positive. 6 of these 11 were patch tested to HDI (1% pet.) and all 6 were positive. It appears that HDI in our group of clothing workers acted as a potent sensitizer affecting around 10% of the workforce.     

Rate-Dependent Threshold Changes During Atrial Pacing: Clinical and Experimental Studies

In 36 patients undergoing a permanent right atrial pacing for the treatment of sick sinus syndrome and/or atrioventricular block, the stimulation threshold was determined at a wide range of pacing rates (60 to 120 beats/min) 7 to 10 days after the lead implantation. Twenty-nine (80%) of these cases showed rate-dependent threshold changes, with significantly lower thresholds at higher than lower pacing rates (e.g., 2.91 +/- 1.01 mA at 70 beats/min and 2.32 +/- 0.75 mA at 120 beats/min, P less than 0.01). Thus, with a fixed, smaller current strength, the stimuli often failed to capture the right atrium at lower rates, but caused a 1:1 capture at higher rates. In an echocardiographic study in another series of eight patients, the end-diastolic diameter of the left atrium was decreased from 3.2 +/- 0.9 to 2.7 +/- 0.8 cm (P less than 0.01) when the pacing rate was increased from 60-70 beats/min to 100-120 beats/min. In experiments using two anesthetized, open-chest dogs, a rapid withdrawal of 500 mL of arterial blood reduced the right atrial dimension. This was accompanied by an increased amplitude of the right atrial endocardial electrogram, and the initially subthreshold stimuli became effective in capturing the atria. It was concluded that (1) rate-dependent threshold changes were commonly observed in the early stage of atrial pacing, and (2) fluctuations in the electrode contact with the endocardium appeared responsible for such threshold changes.