Biomedical subjects

C A Riordan

Publications and source records attributed to C A Riordan.

4 recordsLinked to original sources

PubMed1993

Isotretinoin-associated pseudoporphyria.

We present two patients who developed pseudoporphyria whilst taking isotretinoin (Roaccutane). At that time, both patients were receiving other agents which could be incriminated as causing their pseudoporphyria. However, it is significant that these other agents had been longstanding and that the porphyria-like cutaneous changes did not develop until after the introduction of the isotretinoin (Roaccutane). In both cases, withdrawal of the isotretinoin resulted in clinical improvement of their cutaneous signs. The interaction of isotretinoin and another agent, rather than isotretinoin independently, may be involved in the development of pseudoporphyria.

Adult↗

PubMed1992

Unilateral linear capillaritis.

We present four cases of a distinctive type of pigmented purpuric eruption occurring in a striking linear and pseudo-dermatomal distribution in young males. Whilst these cases share some of the clinical and histological features of other pigmented purpuric dermatoses, they are not readily classified with any of the entities so far defined in this group of disorders. We believe these cases represent a distinct group not previously described. Four patients with an unusual pigmented purpuric eruption are presented.

Adolescent↗

PubMed1991

The management of venous ulcers of the legs.

The first step in the management of venous leg ulcers is correct diagnosis of the ulcer as venous in type. Calf pump dysfunction and resultant increased venous pressure are significant factors in the pathogenesis of venous leg ulcers. Good management is aimed at correcting these. Exercise, elevation and compression are the most effective means of achieving this and form the mainstay of treatment. The use of topical preparations entails a high risk of sensitization and irritancy. If these develop, healing may be slowed by further damage to the ulcer tissue. Reducing the number of preparations used and avoiding the injudicious use of topical antibiotics minimises this risk. Frequent assessment of the ulcer is also essential. Once healed, prevention of recurrence is an integral part of correct management of venous leg ulcers.

Anti-Bacterial Agents↗

PubMed1983

Attraction in aversive environments: some evidence for classical conditioning and negative reinforcement.

Predictions derived from misattribution and negative-reinforcement theories concerning the mediators of attraction in aversive environments were examined. Male subjects, expecting to receive either high- or low-intensity shocks, participated with either a male or female confederate who was or was not present during the description of shock intensity. Subjects' arousal, attributions for their arousal, and attraction to the confederate were measured. Results were not consistent with the misattribution hypothesis. The negative-reinforcement hypothesis accurately predicted the arousal and attribution measures. The presence of the confederate did reduce the perceived aversiveness of the shock and made the subjects feel more calm. Additionally, subjects attributed their arousal to the threat and a calming influence to the confederate. Attraction to the confederate was most consistent with an incorporation of both negative-reinforcement and classical conditioning processes. Confederates who were absent during the high-shock threat were found to be most attractive and significantly more attractive than those who were present during the threat. This suggests that although both confederates reduced arousal, the one present during threat also took on some of the negative qualities of that threat, as would be expected to result from classical conditioning processes.

Adolescent↗