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Biomedical subjects

F Humphreys

Publications and source records attributed to F Humphreys.

27 records · Page 2Linked to original sources
PubMed1991

The effects of astemizole, cetirizine and loratadine on the time course of weal and flare reactions to histamine, codeine and antigen.

An open cross-over study was performed to assess the effects of astemizole, cetirizine and loratadine on weal and flare reactions to intradermal histamine, codeine and house dust mite antigen. Percentage inhibition of weal area, flare area and weal volume was greatest for cetirizine, then astemizole and smallest for loratadine. Wealing due to mast-cell degranulation with either codeine or antigen was less inhibited by all three antihistamines than that due to histamine itself. Time-course studies revealed similarities between wealing provoked by codeine and histamine but different characteristics to that induced by antigen.

Adult↗
PubMed1990

The effect of indomethacin on the kinetics of histamine, 48/80 and antigen wealing.

1. The kinetics of weal formation and disappearance following intradermal injection of histamine, compound 48/80 and antigen were measured in indomethacin and inert geltreated human forearm skin. 2. Rates of formation went in descending order for histamine, 48/80 and antigen; rate constants of disappearance for equal sized weals were the same for histamine and 48/80 but were much less for antigen. The corresponding half-lives were 77, 73 and 160 min for histamine, 48/80 and antigen weal disappearance respectively. 3. Cyclo-oxygenase inhibition by topical indomethacin had no effect either on the immediate weal and flare responses or on the rates of formation and disappearance of the weals. 4. These findings together with previous studies using H1-receptor antagonists indicate that 48/80 acts by histamine release but that antigen releases both histamine and an additional material or materials which are not related to cyclo-oxygenase activity. 5. Exacerbation of chronic idiopathic urticaria by cyclo-oxygenase inhibitors is therefore likely to be part of the urticarial disease process.

Adult↗
PubMed1987

The effect of topical dimethindene maleate on weal reactions.

The topical effect of the histamine H1-receptor antagonist dimethindene maleate on the wealing response to intradermal histamine, compound 48/80 and house dust mite antigen was studied in 16 subjects using a double-blind procedure. The mean reduction in weal area +/- s.e. mean was 44% +/- 13%, 43% +/- 13% and 31% +/- 13% for histamine, 48/80 and antigen respectively. We conclude that dimethindene maleate is a moderately potent H1-receptor antagonist, and that the inhibition of the 48/80 and house dust mite induced weals is accounted for by the antihistaminic effect of dimethindene maleate.

Adult↗
PubMed1987

The effect of nedocromil on weal reactions in human skin.

1. Nedocromil 2% iontophoresed into human skin had no effect on wealing produced by intradermal histamine, 48/80 or house dust mite antigen. 2. Iontophoresis of 0.002-2% nedocromil itself resulted in dose-related wealing. 3. This wealing was reduced by 62 +/- 8% s.e. mean by the H1-receptor antagonist terfenadine which decreased histamine wealing by 68 +/- 2% s.e. mean. 4. Nedocromil may therefore act as a weak agonist on a skin mast cell receptor concerned with histamine release.

Adult↗
PubMed1984

Massive subcutaneous emphysema following colonoscopy.

A case of massive subcutaneous emphysema following colonoscopic polypectomy is reported. The incidence of colonic perforation following colonoscopy is 0.1% and may be intraperitoneal or retroperitoneal. Intraperitoneal perforation is usually immediately apparent and likely to require urgent surgical exploration. The development of subcutaneous emphysema or a pneumoscrotum suggests a retroperitoneal perforation and in the majority of cases management is conservative. Contrast studies are often unhelpful but plain x-rays may help to distinguish between intraperitoneal and retroperitoneal perforations.

Aged↗