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Biomedical subjects

M W Greaves

Publications and source records attributed to M W Greaves.

At least 163 records · Page 9Linked to original sources
PubMed1987

Prostaglandin D2 release by guinea pig skin during in vitro anaphylaxis induced by antigen and compound 48/80.

The release of prostaglandin D2 (PGD2), prostaglandin E2 (PGE2), and histamine induced by antigen and compound 48/80 was studied using an in vitro model of anaphylaxis in guinea pig skin. Abdominal skin from ovalbumin-sensitized guinea pigs was cut into 0.5-1.0 mm-thick slices which were incubated in Tyrode solution at 37 degrees C with or without either ovalbumin or 48/80. Released PGD2 and PGE2 were measured by radioimmunoassay and gas chromatography-mass spectrometry, respectively. Release of PGD2 was detectable at 2 min after challenge (50 micrograms/ml ovalbumin), reaching a maximum at about 15 min. Histamine release was more rapid, achieving 50% of maximum at about 4 min compared to about 7 min for PGD2. In 11 experiments incubation with ovalbumin (50 micrograms/ml for 10 min) induced a significant 6-fold increase in PGD2 compared to unchallenged controls (399 +/- 53 and 67 +/- 19 ng/g dry weight skin, respectively; mean +/- SEM) and a net 47.2% histamine release. In contrast, a smaller (27%) rise in PGE2 was found. Indomethacin (14 microns) completely suppressed evoked PGD2 and PGE2 synthesis without evident effect on histamine release, suggesting that the release of histamine in this model is not dependent on prostaglandin production. The mast cell degranulating agent compound 48/80 (50 micrograms/ml) released significant amounts of PGD2 (340 +/- 86 ng/g skin compared to 89 +/- 30 ng/g for control skin, n = 5) but had no appreciable effect on PGE2. These results show that guinea pig skin can synthesize significant quantities of PGD2 in anaphylactic reactions. Prostaglandin D2 produced in acute allergic reactions in skin in vivo may contribute to the inflammatory reaction, either directly or in synergism with other mediators.

Anaphylaxis↗
PubMed1987

Cimetidine and chlorpheniramine in the treatment of chronic idiopathic urticaria: a multi-centre randomized double-blind study.

One hundred and twenty patients with chronic idiopathic urticaria, who entered a study at five centres (Sheffield, London, Bristol, Cardiff and Leeds) were treated with therapeutic doses of the H1 antagonist chlorpheniramine for 6 weeks. Histamine H1 non-responders (40 patients) were entered into a double-blind study and received chlorpheniramine plus cimetidine 400 mg q.d.s. (21 patients) or chlorpheniramine plus placebo (19 patients) for a further 8 weeks. The most important response measure was the change from baseline of the total symptom score: an assessment of the number and duration of new weals and degree of itching. There was a statistically significant difference between the average response in the two treatment groups in favour of chlorpheniramine plus cimetidine after 4 and 8 weeks' treatment (P less than 0.05 and P less than 0.01, respectively). No significant side-effects related to treatment were noted.

Chlorpheniramine↗
PubMed1987

Symptomatic dermographism (factitious urticaria)--passive transfer experiments from human to monkey.

Passive transfer experiments were carried out on three species of monkey, Macaca mulatta, Macaca nemestrina and Macaca fascicularis, using human serum from patients affected with severe symptomatic dermographism (factitious urticaria), cholinergic urticaria, chronic idiopathic urticaria and normal subjects. The monkeys were tested for dermographism by means of a calibrated dermographometer 24 h after intradermal injection of the serum, using Evans blue as a marker. Positive responses were seen initially in the M. nemestrina. Four sites injected with serum from patients with severe symptomatic dermographism gave positive responses, one site injected with serum from a normal subject produced a faint response. One of the four responses was reproduced one month later in M. fascicularis. These results indicate that passive transfer of dermographism is possible from human to monkey.

Animals↗
PubMed1987

Polycythaemia rubra vera and water-induced pruritus: blood histamine levels and cutaneous fibrinolytic activity before and after water challenge.

We studied blood histamine activity (HA) and cutaneous fibrinolytic activity (CFA) in a patient with polycythaemia rubra vera (PRV) and water-induced pruritus, before and after water exposure. The results suggest that the water-induced itching in PRV is associated with an increase in HA. In addition, markedly increased levels of CFA were found both before and after water exposure. These findings have been previously reported in patients with aquagenic pruritus (AP) but not in patients with PRV. As the water-induced itching in PRV and AP share many common features, these findings suggest that the pathophysiology of the water-induced pruritus in these two conditions may be similar.

Fibrinolysis↗
PubMed1987

The cellular inflammatory response in nicotinate skin reactions.

Sequential skin biopsies of nicotinate-treated skin from nine normal subjects, three aspirin-pretreated normal subjects and six atopic eczema patients were examined. An erythematous skin reaction was seen in the nine normal subjects and to a lesser degree in one atopic eczema patient, but not in the aspirin-pretreated subjects nor in five remaining atopics. Accumulation of a mononuclear cell perivascular infiltrate was seen from 15 min onwards in the normal subjects. Neutrophils became the predominant cell invading thickened vessel walls and in the perivascular space beginning at 2 h and persisting up to 48 h. Leucocytoclasis was observed at 24 h. Immunofluorescence studies showed only non-specific fibrinogen deposits in papillary capillaries in the three groups of subjects. The chloroacetate esterase reaction and immunohistochemical labelling with OKM I confirmed a marked neutrophilia at 2 h and 24 h. Neutrophils were seen in one atopic eczema patient, but were not observed in the remainder, nor in the skin of the aspirin-pretreated normal subjects. Topical application of nicotinate causes non-allergenic, leucocytoclastic vascular damage in normal skin which can be inhibited by aspirin and which is reduced or absent in atopic eczema.

Adult↗
PubMed1987

Response of psoriatic lesions to multiple applications of leukotriene B4 and 12-HETE.

Single topical application of the neutrophil chemoattractant arachidonic acid metabolites leukotriene B4 (LTB4) and 12-R,S-hydroxy-5,8,10,14-eicosatetraenoic acid [corrected] (12-HETE) to normal skin elicits a histological response similar to early psoriasis. This effect diminishes following repeated application indicating the development of local tolerance. In order to assess whether induction of tolerance could be exploited as a treatment for psoriasis we studied the clinical effects of topical application of LTB4 (n = 6) and 12-HETE (n = 3) under occlusion to small psoriatic lesions for 12 consecutive days. The area of the control lesions decreased significantly over the study period while the areas of lesions to which LTB4 and 12-HETE were applied remained unchanged. No other difference between responses of the three groups was detected. We have shown that, in the doses used, multiple applications of these substances to established stable psoriatic lesions do not produce a therapeutically useful response.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1987

Hexyl-nicotinate-induced vasodilation in normal human skin.

Hexyl nicotinate in a lotion formulation was applied topically to the skin of 10 healthy volunteers with clinically normal skin. Erythematous responses were assessed visually and skin blood flow determined by means of a laser Doppler flow meter which measures the blood cell flux (Pf2 Perimed, Sweden). Mean erythematous responses and increased blood cell flux were dose-related but in several subjects increases in blood flow occurred in the presence of barely detectable erythematous responses. In some subjects, hexyl nicotinate may be an effective cutaneous vasodilator even in the presence of minimal erythema.

Administration, Topical↗
PubMed1987

Release in vivo of IL-1 like activity by human skin.

We have demonstrated the release in vivo by normal human skin of a factor which possesses IL-1-like activity in the mouse thymocyte amplification assay. Quantitatively similar amounts of this factor were released from involved and uninvolved skin of patients with cutaneous T cell lymphoma. The IL-1-like factor was associated with inhibitory activity in the mouse thymocyte amplification assay. High performance liquid chromatographic analysis showed that this inhibitory activity co-chromatographed with prostaglandin E2. These results provide further evidence for the role of the skin as an immunologically active organ and suggest that PGE2 may have an immunomodulatory role in human skin.

Animals↗
PubMed1986

Psoriatic skin lesions contain biologically active amounts of an interleukin 1-like compound.

The presence of neutrophil chemoattractant material in aqueous extracts of lesional psoriatic scale has been investigated by use of an agarose microdroplet chemokinesis method in combination with ultrafiltration and high-performance liquid chromatography (HPLC). Fractions were also assayed for murine thymocyte co-stimulating activity. Aqueous extracts of psoriatic scale contained significantly greater neutrophil chemokinetic activity than extracts of scale from normal skin. Successive ultrafiltration of extracts showed that the chemokinetic material was 10 to 30 kd. Heat lability and gel filtration HPLC characteristics suggested that the major chemokinetically active material in aqueous extracts of psoriatic scale is different from C5a des arg. Reversed-phase HPLC of 0.1% trifluoroacetic acid/acetonitrile extracts of psoriatic scale revealed two clearly resolved peaks of chemokinetic activity, the major peak consistently containing thymocyte co-stimulating activity. No significant neutrophil chemokinetic activity was seen in fractions after reversed-phase HPLC of scale from normal skin. These findings suggest that a major portion of the neutrophil chemoattractant activity in aqueous extracts of psoriatic scale is due to interleukin 1-like material, which may play a role in the pathogenesis of this disease.

Adult↗
PubMed1986

The chemokinetic response of psoriatic and normal polymorphonuclear leukocytes to arachidonic acid lipoxygenase products.

Polymorphonuclear leukocytes (PMN) from ten patients with chronic stable plaque psoriasis, five of whom had more than 40% skin involvement and five with less than 20% involvement, responded in a dose-related fashion to stimulation with the arachidonic acid lipoxygenase products 5- and 12-hydroxyeicosatetraenoic acid (5- and 12-HETE) and leukotriene B4 (LTB4) in an in vitro chemokinesis assay. There was no significant difference in either the random migration or the chemokinetic response of psoriatic PMN to LTB4 when compared to the responses of PMN from a group of age- and sex-matched healthy controls. Psoriatic PMN migrated further in response to low doses of 5- and 12-HETE although the distance moved after maximal stimulation was no different to that observed in controls. No significant difference was observed in the responses of PMN obtained from patients with less than 20% skin involvement when compared to those with more extensive psoriasis. The small differences measured between the chemokinetic responses of psoriatic and control PMN to the lipoxygenase products tested are unlikely to be of pathogenetic significance.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

Prostaglandin D2 and histamine release in cold urticaria.

Prostaglandin (PG) D2 and histamine concentrations have been measured in blood draining cold-challenged forearm skin in patients with cold urticaria. Local venous concentrations of both histamine and PGD2 rose in four patients who developed a whealing response. Plasma histamine concentration increased from a mean resting value of 0.24 +/- 0.09 (SD) ng/ml to peak values of 16.9 to 96.6 ng/ml. Resting concentrations of PGD2 were below the limit of detection (5 pg/ml) in three patients and 62 and 27 pg/ml in the fourth. Peak plasma PGD2 concentration after challenge ranged from 166 to 279 pg/ml. Time course of histamine and PGD2 release was similar with peak concentrations at 6 and 10 minutes, respectively. The maximum clinical response occurred between 10 and 20 minutes after challenge. Our findings demonstrate that PGD2 is produced in association with mast cell degranulation in man, but the amount, relative to histamine, is low. Despite its high potency in production of inflammatory effects, PGD2 probably has only minor direct effects in cold urticaria, although it may act to potentiate other mediators.

Adolescent↗