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Biomedical subjects

C C Lyon

Publications and source records attributed to C C Lyon.

35 records · Page 2Linked to original sources
PubMed1998

Subacute cutaneous lupus erythematosus: two cases of delayed diagnosis.

Two cases of subacute cutaneous lupus erythematosus are described. Features which delayed diagnosis are discussed. The potential clinical and histopathological overlap between this condition and erythema multiforme is emphasized, drawing attention to the histological features which allow distinction. The possibility that some cases of Rowell's syndrome may be manifestations of subacute lupus erythematosus is discussed.

Aged↗
PubMed1998

Bowlers' grip.

Explore the source record for details and available documents.

Dermatitis, Allergic Contact↗
PubMed1997

A portable digital imaging system in dermatology: diagnostic and educational applications.

Digital photographs were taken by a trainee dermatologist of the presenting lesions of 100 unselected, consecutive new patients. For the 38 patients presenting with rashes there was clinical disagreement in only four cases (10%). For the 62 patients with tumours there was clinical disagreement in three cases (3.8%). In a further three cases both clinicians agreed on a differential diagnosis which was subsequently disproved by histological findings and clinical progress. The study demonstrated that an affordable, low-resolution, fixed-focus digital camera with close-up lenses could provide diagnostically useful images suitable for telediagnosis in dermatology.

Dermatology↗
PubMed1997

Digital imaging and teledermatology: educational and diagnostic applications of a portable digital imaging system for the trainee dermatologist.

Teledermatology is no longer a futuristic curiosity; several general practices across the UK are now preparing to be electronically linked to other medical services for the purposes of referral and telediagnosis. Further, digital imaging in dermatology has been the subject of considerable research in recent years, largely because of its application to telemedicine. Indeed in the UK, geographically isolated general practices in North Powys have already demonstrated the effective delivery of dermatological expertise through a video-conferencing link to a consultant dermatologist at Aberystwyth Hospital, thereby reducing the need for patients or the consultant to travel long distances.

Dermatology↗
PubMed1987

Reduced plasma renin activity in elderly subjects in response to vasovagal hypotension and head-up tilt.

The sympathoadrenal and renin-angiotensin systems play an important role in the cardiovascular responses induced by head-up tilt. In young people, hypotension and postural changes induced by tilt produce significant increases in plasma renin activity. The response of plasma renin activity to prolonged tilt and subsequent vasovagal hypotension has not been assessed in the elderly. Seventeen elderly subjects (10 with carotid sinus syndrome and seven age-matched controls) were studied during 45 minutes of recumbency and 120 minutes of head-up tilt to 40 degrees. Intra-arterial systolic blood pressure and heart rate were monitored continuously and plasma renin activity was measured at frequent intervals. Ten subjects developed vasovagal syncope during tilt (at 32 +/- 18 min). Systolic blood pressure and heart rate fell by 70 +/- 20 mmHg and 20 +/- 7 beats . min-1 (P less than 0.001 and P less than 0.01, respectively). Plasma renin activity did not change in syncopal subjects and remained unchanged up to 60 min after syncope. In seven subjects who completed 120 min of tilt without symptoms, heart rate rose during tilt but plasma renin activity remained unchanged. Plasma renin activity is not influenced by marked hypotension or prolonged head-up tilt in the elderly.

Aged↗
PubMed1987

Enhanced vagal activity and normal arginine vasopressin response in carotid sinus syndrome: implications for a central abnormality in carotid sinus hypersensitivity.

The relation between arginine vasopressin and vagal activity in carotid sinus syndrome was studied in 10 patients and 17 age matched controls using head up tilt as a stimulus. Of the controls, seven had unexplained syncope and 10 were healthy elderly subjects with no previous history of syncope. Subjects were studied supine for 45 min and thereafter during 120 min head up tilt to 40 degrees. Phasic arterial pressure and heart rate were monitored throughout. Serum was sampled at frequent intervals to measure arginine vasopressin, noradrenaline, and adrenaline concentrations. Seventy per cent of carotid sinus patients had vasovagal syncope at (mean(SD)) 25(4) min after tilt compared with 43% of subjects with unexplained syncope and one healthy elderly control. The maximum (mean(SD)) fall in systolic blood pressure and heart rate was 70(20) mmHg and 20(7) beats.min-1 (p less than 0.001 and p less than 0.01 respectively). Arginine vasopressin, noradrenaline, and adrenaline concentrations rose significantly in syncopal subjects (p less than 0.001, p less than 0.01, and p less than 0.05 respectively). Changes in systolic blood pressure, heart rate, and hormone concentrations were similar for patients with carotid sinus syndrome and control subjects. For those who completed the tilt period without the development of symptoms, systolic blood pressure and arginine vasopressin and adrenaline concentrations were unchanged, whereas noradrenaline concentrations and heart rate rose significantly. Vasovagal activity is thus appreciably increased in carotid sinus syndrome. Furthermore, the afferent limb of the carotid sinus reflex appears to be intact in patients with carotid sinus syndrome since the pattern of arginine vasopressin release was not different from controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1986

Antidiuretic effect and pharmacokinetics of oral 1-desamino-8-D-arginine vasopressin. 1. Studies in adults and children.

The dose-response relationships and pharmacokinetics of orally administered 1-desamino-8-D-AVP (DDAVP) were investigated. In water-loaded normal subjects marked reductions in urine flow rate and increases in urinary osmolality occurred. The responses were maximal 2 h after ingestion of 50, 100, and 200 micrograms, and lasted at least 6 h. Plasma DDAVP levels increased in a dose-dependent fashion and its disappearance from the plasma followed an exponential time course, with a half-life 86 to 142 min. In water-loaded adults with central diabetes insipidus (CDI), 200 micrograms oral DDAVP caused marked antidiuresis and mean urinary osmolality increased from 107 mosm/kg to 554 mosm/kg after 3 h. In these patients the effect also lasted at least 6 h. Children with CDI were less sensitive than normal subjects to the 50-microgram dosage and required 100 micrograms orally to achieve a duration of action similar to that resulting from 200 micrograms in adults. Oral DDAVP may be useful for treating some patients with CDI.

Administration, Intranasal↗
PubMedDate not supplied

Pseudoephedrine toxicity in renal failure.

A case of pseudoephedrine toxicity is reported in a man with chronic renal failure. The effects of renal impairment on the metabolism of pseudoephedrine are discussed and the implications of the widespread availability of the drug in proprietary cold remedies are highlighted.

Adult↗