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Biomedical subjects

A Hopkirk

Publications and source records attributed to A Hopkirk.

5 recordsLinked to original sources
PubMed1990

Attenuation of nocturnal asthma by cromakalim.

In a randomised, double-blind, crossover study, single oral doses of cromakalim, a potassium-channel activator, or placebo were given to 23 patients with nocturnal asthma. There was a significant reduction (p less than 0.005) in the early morning fall in forced expiratory volume in 1 s (FEV1) after 0.5 mg cromakalim (fall 9.8% [SEM 3.2%]) compared with placebo (18.5 [2.8]%). In a repeat dosing study, administration of 0.25 mg and 0.5 mg cromakalim on 5 consecutive nights to a further group of 8 asthmatic subjects significantly reduced the early morning fall in FEV1 from 28.7 (6.5)% after placebo to 19 (4.2)% after 0.25 mg and 14.9 (6.5)% after 0.5 mg. Potassium-channel activators may be useful in the treatment of asthma, especially for nocturnal symptoms.

Adult↗
PubMed1985

Occupational asthma due to methyl methacrylate and cyanoacrylates.

Five patients had asthma provoked by cyanoacrylates and one by methyl methacrylate, possibly because of the development of a specific hypersensitivity response. Acrylates have wide domestic as well as industrial uses, and inhalation of vapour emitted during their use can cause asthma.

Adult↗
PubMed1979

Normal electrocardiographic waveform characteristics during treadmill exercise testing.

Forty asymptomatic male patients at low risk for cardiovascular disease completed maximal treadmill testing. Electrocardiograms from leads CC5, CM5, V5, Yh and Z were recorded across multiple pretest, exercise and recovery conditions. ECG waveforms were subsequently digitized, averaged and processed to provide Q-, R-, S- and T-wave amplitudes, ST-segment means and slopes, and QS- and RT-interval durations. Average R-wave amplitude increased during early exercise and then dramatically decreased to maximum effort. Average S-wave amplitude became greater as exercise progressed. Average J junction was slightly positive before exercise, became negative during exercise (except lead Z) and returned to zero after exercise. The ST-segment slope increased dramatically with progressive exercise. The response of T-wave amplitude, RT and QS intervals are also described. Separately, 22 asymptomatic male subjects each completed two maximal treadmill tests 2 weeks apart. ECG data acquisition and processing were similar to those noted above. Pooled, within-subject estimates of variability were computed for the ECG leads, ECG measurements and protocol conditions. These variability estimates are useful for interpreting ECG responses to exercise testing.

Adult↗