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M Houlihan

Publications and source records attributed to M Houlihan.

5 recordsLinked to original sources
PubMed2001

EEG effects of smoking: Is there tachyphylaxis?

Smoking generally affects the human EEG by reducing low-frequency activity and increasing higher-frequency activity. Using a double-blind design, we sought to determine if acute tolerance (tachyphylaxis) to this effect can be observed. EEG was recorded in overnight-abstaining participants before and after smoking three cigarettes at 40-min intervals in two separate sessions. In one session ('short interval'), all three cigarettes had 'typical' nicotine yields (1.1 mg, FTC method). In the other session ('long interval'), the second cigarette had a very low nicotine yield (0.05 mg; thus making the interval between 1.1-mg cigarettes 80 min). Eyes-closed alpha power decreased and eyes-open beta-2 power increased following smoking each of the 'typical-yield' cigarettes but not the low-yield cigarettes. The decrease in alpha power after smoking the 'typical-yield' cigarette at the 40- and 80-min intervals was less than that following the first cigarette of the day, indicating tachyphylaxis. In contrast, the increase in eyes-open beta-2 power did not differ among cigarettes regardless of the order or interval between 'typical-yield' cigarettes. EEG changes in other frequency bands produced by smoking the first cigarette of the day were not consistent across sessions, making interpretation in terms of tachyphylaxis somewhat problematic. Overall, lower-frequency alpha activity displayed patterns consistent with tachyphylaxis while beta-2 did not.

Adult↗
PubMed1997

Unilateral papilloedema in a 12 year old girl--a surprising diagnosis.

A previously well 12 year old girl presented with diminished visual acuity and haziness of her left eye. Her examination confirmed visual loss in her left eye and significant disc blurring on fundoscopy. Extensive investigations including computerised tomography of the brain and orbit were normal. Her serum angiotensin converting enzyme (ACE) levels were elevated and subsequent Kveim test was positive confirming the diagnosis of ocular sarcoidosis. She did respond to a course of systemic steroids and over the following 3 years her eye signs and symptoms did correlate well with the ACE level. To date she has not had any systemic or respiratory symptoms. Thus sarcoidosis should be considered in the differential diagnosis of ocular pathology of unexplained aetiology.

Child↗