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1 3-hydroxy-5-trifluoromethyl-N-[2-(2-thienyl)-2-phenyl-ethenyl]- benzo(B) thiophene-2-carboxamide (L-652,343) is a 5-lipoxygenase and cyclo-oxygenase inhibitor in vitro. 2 In psoriasis increased concentrations of arachidonic acid transformation products are found in the lesional skin which may be important in the pathogenesis of the disease. We have measured the effect of orally administered L-652,343 on the concentration of LTB4 and prostaglandins in the lesional skin. 3 Eight patients with stable chronic plaque psoriasis received 500 and 250 mg of L-652,343, 12 h apart. A chamber technique was used to collect skin exudate samples from abraded plaques before and at 4, 24 and 48 h after the first dose. Exudates were analysed for LTB4 by a neutrophil chemokinesis assay and for PGE2 and PGD2 by RIA. 4 PGE2 and PGD2 levels were significantly reduced at 4 and 24 h after the first dose of L-652,343 but LTB4 levels were not affected indicating inhibition of the cyclo-oxygenase pathway but not of the 5-lipoxygenase pathway. This shows the importance of confirming that the action of 5- lipoxygenase inhibiting drugs in vitro occurs in vivo. [ABSTRACT FROM AUTHOR]

Glomangiomas are rare cutaneous tumours composed of glomus cells, which are modified smooth muscle cells. The aetiology of this condition is thought to involve a mutation in a novel gene acting to regulate angiogenesis. We report a patient from a large family with three generations affected by familial multiple glomangiomas. We hypothesized that the growth factors basic fibroblast growth factor and vascular endothelial growth factor, which stimulate/regulate angiogenesis could be involved in the pathogenesis of these lesions. Therefore, using enzyme-linked immunosorbent assays and immunohistochemistry, respectively, we measured systemic and tissue levels of these growth factors in a patient with familial glomangiomas. In addition, we investigated endothelial mitogenicity of the patient's serum as a functional assay of systemic growth factor activity.

Evidence indicates that the neurotrophin nerve growth factor (NGF) is a mediator of cutaneous inflammatory responses. Cellular responses to NGF are facilitated by two receptors called trk A and p75 neurotrophin receptor (p75NTR). In the current study we have investigated the expression of these receptors in lesional and non-lesional skin from patients with plaque psoriasis and in normal skin exposed to three times the minimal erythema dose of ultraviolet (UV) B radiation. Trk A immunostaining was confined to the basal keratinocytes in normal skin. There was a significant reduction in trk A immunostaining in both non-lesional and lesional psoriatic skin compared with control skin. In UVB-irradiated normal skin, there was a significant reduction in trk A immunostaining at 4 h after irradiation, which was still evident at 48 h. In normal skin, p75NTR immunopositive fine nerve fibres were present throughout the dermis and occasionally seen in the epidermis. Thick nerve fibres were evident in the deep dermis and in the middle region of the dermis. p75NTR immunopositive basal keratinocytes were occasionally seen. There was a statistically significant loss of p75NTR immunopositive fine nerve fibres in the epidermis of lesional psoriatic skin and a statistically significant loss of p75NTR immunopositive fine nerve fibres in the dermis in both non-lesional and lesional psoriatic skin. p75NTR immunopositive thick nerve fibres were reduced in lesional psoriatic skin compared with normal skin. UVB irradiation of normal skin led to a statistically significant decrease in the p75NTR immunopositive fine nerve fibres in the epidermis at 48 h after irradiation. There was no significant reduction in the dermal p75NTR immunoreactivity. These results demonstrated that expression of both NGF receptors is decreased following an acute inflammatory stimulus and also in association with a chronic inflammatory dermatosis.

This study was undertaken to ascertain the histopathology and aetiology of cutaneous nodules observed in Parkinson's patients treated with continuous subcutaneous apomorphine. Ten patients were recruited, answered questionnaires, and underwent skin biopsies and full blood count, and nine were patch tested to apomorphine and its preservative. Six had serum IgE levels measured. A florid panniculitis was seen in all biopsies; five were predominantly eosinophilic, three lymphocytic and two neutrophilic; in seven cases the panniculitis was mixed and in three it was septal. Patch testing was universally negative and the IgE levels were normal.

Vibration white finger (VWF) is the episodic blanching of the fingers that occurs in response to cold in those who work with hand-held vibrating tools. Clinically the condition differs from primary Raynaud's phenomenon as persistent pain and paresthesia are common in the hands and arms and occur independently of the "white attacks." We have previously reported a decrease in protein gene product 9.5 and calcitonin gene-related peptide-immunoreactive nerve fibers in the digital skin of individuals with VWF. In this study, we have sought to determine whether this deficit of immunoreactive sensory-motor nerves has a functional counterpart in vivo. Histamine produces a rapid wheal and flare response following intradermal injection, whereas endothelin-1 (ET-1) produces a central area of pallor with a surrounding neurogenic flare. In contrast, calcitonin gene-related peptide produces a non-neurogenic erythema. In this study, histamine and ET-1 were injected into the dorsum of the middle phalanx and the local neurovascular response was assessed by measuring the area of the visible flare or pallor. Basal finger blood flow was also measured by laser Doppler flowmetry in each of the digits prior to intradermal injection. The experiments were performed at 21 degrees C and 4 degrees C. Patients with VWF and asymptomatic vibration-exposed workers had significantly lower resting skin blood flow at both 21 degrees C and 4 degrees C than heavy manual workers with no vibration exposure. The size of the histamine- and ET-1-induced flares at both 21 degrees C and 4 degrees C was significantly smaller in patients with VWF when compared with the asymptomatic vibration-exposed workers and heavy manual workers. The size of the ET-1-induced pallor was smaller in patients with VWF when compared with the heavy manual workers at both 21 degrees C and 4 degrees C. In contrast, the area of erythema induced by intradermal injection of calcitonin gene-related peptide at both 21 degrees C and 4 degrees C was of a similar size in patients with VWF and in heavy manual workers. These results indicate that the neuroneal deficit identified by immunohistochemistry in the digital skin of patients with VWF has a functional counterpart in vivo and is evident as a reduced ability to propagate an axon-reflex vasodilator response when challenged with histamine and ET-1. Furthermore, these results enable patients with VWF to be differentiated from both asymptomatic vibration-exposed workers, in whom the histamine- and ET-1-induced flares are normal, and those with primary Raynaud's disease, in whom the ET-1 flare is reduced and the histamine-induced flare is normal.

A 1 year, prospective multicentre study was performed to investigate the efficacy and safety of intermittent treatment with cyclosporin in psoriasis vulgaris. Subjects received cyclosporin (Neoral) 5 mg/kg per day until achieving 90% reduction in area affected, or for a maximum of 12 weeks. Those failing to demonstrate a satisfactory response were withdrawn. When further treatment was required, cyclosporin was recommenced. This cycle was repeated up to three times. Psoriasis activity was recorded using the area affected and sign scores for erythema, scaling and infiltration. Overall assessments of response and tolerability were recorded. Forty-one subjects, mean age 36, mean PASI 12.8, entered the first treatment period. Thirty-three received a second period of treatment and 16 a third. Eighteen failed to complete the study as planned: five were withdrawn due to adverse events, four due to treatment failure and nine due to protocol violations. At the end of each treatment period, significant improvements were seen in all efficacy parameters. Overall response was graded as 'considerable improvement' or 'minimal or no symptoms', by over 80% of subjects and investigators. Median intervals to relapse for subjects remaining in the study were 72 days (range 28-329) and 53 days (range 14-141) after periods 1 and 2, respectively. There were significant increases in mean serum creatinine and blood pressure during each treatment period. However, there were no significant differences in either parameter between baseline and the final follow-up visit. At the end of each treatment period, overall tolerability of the treatment was considered 'good' or 'very good' by over 80% of subjects and investigators.

Aseptic loosening is seen in a significant proportion of cemented total hip replacements (THR). In a small subgroup of patients who suffer early loosening polyethylene debris is unlikely to be responsible. We recently reported one case of allergic contact dermatitis to N,N-dimethylparatoluidine (DMT), an accelerator used in bone cement. We have therefore investigated this using skin-patch tests to a variety of substances including metals, polyethylene and the separated individual components of Simplex cement. We studied 70 patients, 15 with aseptic loosening less than two years after THR, 25 with satisfactory long-term cemented fixation, five with infected loosening of cemented THRs and 25 awaiting hip arthroplasty. We found seven positive reactions to DMT, all of them in patients with the rapid onset of aseptic loosening. Allergy to DMT is recognized in the dental profession in respect of the 'denture sore mouth' syndrome, and could also be an occupational hazard since some industrial glues contain DMT. Our results suggest the need for awareness of possible previous dental or occupational exposure of the constituents of bone cement. We recommend the use of skin-patch testing in high-risk cases.

Systemic sclerosis is an uncommon multisystem disorder of unknown aetiology which predominantly affects the skin. Cardiac involvement, which is far more common than was originally realized, may affect any part of the heart but most frequently affects the left ventricular myocardium. Right ventricular dysfunction is usually associated with pulmonary vascular disease. We report a case of systemic sclerosis associated with right ventricular cardiomyopathy in whom pulmonary artery pressures were normal.

Nitric oxide is a potent mediator of endothelium-dependent vasodilation, the synthesis of which is catalyzed by the constitutively expressed enzyme endothelial nitric oxide synthase. In this study we have investigated whether human dermal microvascular endothelial cells express endothelial oxide synthase and whether the vasodilator neuropeptides, calcitonin gene-related peptide and substance P, stimulate the release of nitric oxide from these cells. Endothelial nitric oxide synthase was identified by immunohistochemistry in the blood vessels in both the papillary and deep dermis of normal skin, and also in monolayers of human dermal microvascular extracts prepared from both the dermis of normal human skin and human dermal microvascular endothelial cells, a 135-kDa band corresponding to endothelial nitric oxide synthase was identified. Nitric oxide was released from unstimulated human dermal microvascular endothelial cells as assessed by inhibition of platelet aggregation and nitrate formation. Endothelial cell-mediated inhibition of platelet aggregation was blocked by hemoglobin. Calcitonin gene-related peptide, (100 pM to 100 nM) directly inhibited platelet aggregation, and this direct effect was not modulated by microvascular endothelial cells. Substance P (10 nM to 1 muM) and calcitonin gene-related peptide (100 pM to 10 nM) significantly (p<0.05) increased nitrite formation, and this increase was blocked by the competitive nitric oxide synthase antagonist, NG-monomethyl-L-arginine. These results demonstrate that endothelial nitric oxide synthase is expressed in the microvascular endothelium of normal human skin and that human dermal microvascular endothelial cells release nitric oxide constitutively and in response to vasodilator neuropeptides.

It has been argued that the digital cutaneous microvasculature is the site of the anomaly which causes Raynaud's phenomenon (RP). Both endothelin-1 (ET-1), a potent vasoconstrictor peptide present in the digital cutaneous microvasculature, and calcitonin gene-related peptide (CGRP), a powerful vasodilator present in digital cutaneous perivascular nerves, have been implicated in the pathogenesis of RP. Circulating ET-1 levels are raised, and there is a diminution of CGRP-containing perivascular nerves in finger skin in RP. We undertook a pharmacological study to investigate the sensitivity of the digital cutaneous microvasculature to intradermal ET-1 and CGRP. Differences were found in RP compared with normal digital skin, supporting the idea that the digital cutaneous microvasculature is actively involved in the pathogenesis of RP. In RP, the erythematous response to ET-1 was diminished at both 20 and 5 degrees C (a low temperature at which RP classically occurs) providing pharmacological support for the morphological evidence that in RP there is a deficiency of CGRP-containing nerves in the distal digital skin.

The effect of topical application of clobetasol propionate ointment (0.05% w/v) on the vascular changes induced by intradermal injections of histamine, calcitonin gene-related peptide, substance P, endothelin-1 and compound 48/80 was studied. Clobetasol propionate ointment was applied topically under occlusion to the forearm skin of healthy volunteers and vehicle base was applied to the contralateral forearm. The intradermal injections were made 4 h or, in a separate study, 72 h after topical steroid application. Responses were measured by planimetry and laser Doppler flowmetry. Four hours application of steroid did not significantly alter the responses to any of the vasoactive substances. After 72 hours application, clobetasol propionate significantly increased the size of the endothelin-1-induced area of vasoconstriction (p < 0.02) and significantly reduced the size of the flares induced by endothelin-1 (p < 0.02), substance P (p < 0.009) and compound 48/80 (p < 0.05). We conclude that the most likely explanation of our data is an inhibition by the steroid of cutaneous mast cell function.

The aim of this study was to investigate in human skin in vivo the role of nitric oxide in maintaining resting vascular tone, in the vasodilatation caused by local warming and by ultraviolet B light exposure, and in the response to exogenous calcitonin gene-related peptide (CGRP). Cutaneous blood flow was assessed by planimetry of the visible erythema or pallor and by laser Doppler flowmetry. Intradermal injection of the inhibitor of nitric oxide synthase, NG-nitro-L-arginine methyl ester (L-NAME; 25 nmol), into forearm skin produced a visible pallor and a reduction of blood flow at a controlled ambient temperature of 21 degrees C. The control, NG-nitro-D-arginine methyl ester (D-NAME; 25 nmol) or NG-monomethyl-L-arginine (L-NMMA; 25 nmol) did not cause pallor or reduce blood flow. L-NAME and L-NMMA caused dose- and time-dependent increases in pallor, and reductions in cutaneous blood flow in skin that had been locally warmed by immersion in water at 45 degrees C and in skin that had been exposed to ultraviolet B light. D-NAME and D-NMMA at comparable concentrations did not have the effects on skin blood flow observed with the L forms. L-NAME and L-NMMA both inhibited the increased blood flow in human skin caused by the intradermal injection of CGRP (12.5 or 25 pmol). The reduction of CGRP-induced increase of blood flow by L-NAME was reversed by L-arginine. Neither D-NAME nor D-NMMA inhibited the increase in blood flow caused by CGRP. Neither L-NAME nor L-NMMA inhibited the increase in blood flow in human skin caused by the intradermal injection of prostaglandin E2 (63 pmol). The data show that nitric oxide is involved in the maintenance of resting blood flow in human skin and also in the cutaneous vasodilator responses to local warming, ultraviolet B irradiation, or injection of CGRP.

Peripheral inflammation induced in adult rats by an intraplantar injection of complete Freund's adjuvant results in a rapid (6 h) increase in the expression of the messenger RNAs for the neuronal growth-associated protein 43 and for preprotachykinin A, the precursor for substance P, in dorsal root ganglion sensory neurons innervating the inflamed area. This increase peaks at 48 h and then declines by five days. The changes are present in the dorsal root ganglion cells innervating the inflamed skin (lumbar 4 or 5) but no elevation was found in the third lumbar dorsal root ganglion which innervates neighbouring non-inflamed skin. The increased growth-associated protein 43 messenger RNA in the dorsal root ganglion is followed by a marked increase in growth-associated protein 43-like immunoreactive fibres in the epidermis of the inflamed skin. Systemic administration of neutralizing anti-nerve growth factor antibodies immediately prior to the inflammation prevents the increase in growth-associated protein 43 and preprotachykinin A messenger RNAs in the sensory neurons. A subcutaneous injection of nerve growth factor (200 ng) into the hindpaw elevates preprotachykinin A but not growth-associated protein 43 messenger RNA in the fourth lumbar dorsal root ganglion 48 h post-injection and this could be prevented by co-administration of the anti-nerve growth factor serum. The production of nerve growth factor in inflamed target tissues leads to alterations in the phenotype of responsive adult primary sensory neurons which include a change in the levels of a growth-related protein and a peptide neuromodulator.(ABSTRACT TRUNCATED AT 250 WORDS)

Src-related cytoplasmic PTKs are physically and functionally associated with cell surface receptors and are involved in signal transduction. In this paper we report the identification of src-related proteins p59fyn, pp60c-src and p62yes in human microvascular endothelial cells cultured from normal human skin and their physical association with the thrombospondin receptor CD36. Such an association represents a potential signalling pathway by which thrombospondin may regulate angiogenesis.

Vibration white finger or hand-arm vibration syndrome is the episodic blanching of the fingers in response to cold occurring in those who work with hand held vibrating tools. Clinically the condition differs from primary Raynaud's phenomenon as persistent paraesthesiae and pain are common in the hands and arms and these occur independently from the 'white attacks'. Symptoms can become severe enough to warrant a change of occupation. Industrial compensation may be awarded for vibration white finger but, at present, no simple or reliable objective diagnostic test is available. Calcitonin gene-related peptide (CGRP) is a neuropeptide with powerful vasodilator properties. A deficiency of immunoreactive CGRP nerve fibres has been previously demonstrated in the digital cutaneous microvasculature of patients with primary and secondary Raynaud's phenomenon with the distribution and quantity of other types of nerve fibres not being significantly altered. To determine if the innervation of the cutaneous microvasculature in vibration white finger was also abnormal skin biopsy samples from the fingers of 15 patients with vibration white finger, six healthy age matched controls who worked with vibrating machinery and 26 healthy age matched controls who were heavy manual workers without exposure to vibrating machinery were examined by immunohistochemistry. To try to correlate any histological abnormalities with clinical neurological deficit sensory nerve conduction studies have so far been performed in six patients with vibration white finger.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcitonin gene-related peptide (CGRP) is a potent vasodilator that may be involved in the regulation of the peripheral circulation and in its response to cold. There is evidence that CGRP in digital cutaneous perivascular nerves is deficient in Raynaud's phenomenon. Our pilot study of intravenous CGRP suggested that this substance is beneficial in patients with Raynaud's phenomenon; here we have extended our studies. Ten patients with severe Raynaud's phenomenon secondary to connective tissue disease were randomly assigned to groups receiving intravenous CGRP (0.6 micrograms/min for 3 h per day on 5 days) or saline. Hand and digital blood flow and skin temperature were measured by thermocouple and laser doppler flowmetry. Blood flow was significantly (p < 0.05) increased by CGRP in both hands (median blood flow after infusion as percentage of baseline reading 179 [range 100-355]%) and fingers (149 [100-161]%); saline had no effect (hands 102 [84-123]%, fingers 96 [81-113]%). Hand temperature was increased more by CGRP than by saline (2.8 [1.5-4.0] vs 1.0 [-1.0 to 2.5] degrees C, p < 0.05). Digital temperature increased after CGRP but the difference between the treatment groups in temperature rise was not significant, perhaps because saline caused increases in some patients. All ulcers healed in four of five CGRP-treated patients but in no saline-treated patients. Thus intravenous CGRP effectively dilates the compromised digital cutaneous vasculature in severe Raynaud's phenomenon.

Malignant atrophic papulosis (Degos disease) is a rare disorder characterized by a vasculopathy of unknown origin. The cutaneous manifestations comprise erythematous papules, which heal to leave scars with a pathognomonic central porcelain-white atrophic area and a peripheral telangiectatic rim. There is usually involvement of the gastrointestinal tract but other organ systems can also be affected, the central nervous system being involved in 20% of cases. It is frequently fatal within 2 or 3 years from onset of systemic involvement, the cause of death usually being intestinal perforation. Our patient is of interest as she has survived an unusually long time despite florid cutaneous and neurological manifestations.

Endothelin (ET), which mediates vasoconstrictor and vasodilator activities via multiple receptor subtypes, has been implicated in the control of blood flow and vascular tone in human skin, and possibly in the abnormal vasoconstrictor response in primary Raynaud's phenomenon and systemic sclerosis. Using in vitro autoradiography we have examined the endothelin-binding characteristics and receptor subtypes of human skin, and sought to provide evidence for endothelin receptor regulation in skin from patients with primary or secondary Raynaud's phenomenon. Specific 125I-ET-1 and 125I-ET-3 binding sites were localized to microvessels of the sub-epidermal plexus and dermal papillae, larger blood vessels, sweat glands, epidermis, and hair follicles. Both ETA and ETB receptors were demonstrated in microvessels and other structures. ET receptor heterogeneity in skin vasculature suggests a role for ET as an autocrine/paracrine regulator of vasoconstrictor and vasodilator pathways in human skin. The presence of binding sites in epidermis and hair follicles suggests a possible mitogenic function for endothelin in human skin. Endothelin-binding density was significantly higher (p < 0.05) in microvessels of skin from patients with systemic sclerosis but not significantly different in Raynaud's phenomenon patients, compared to controls. Lack of down regulation of ET receptors in Raynaud's phenomenon and systemic sclerosis may contribute to the pathogenesis of vasospasm in these diseases.

Basophils have been implicated as a source of histamine and pro-inflammatory eicosanoids in atopic dermatitis. However, mechanisms regulating basophil mediator release are not understood. An H3 receptor involved in the control of histamine synthesis and release has been identified in nervous tissue. In this study we have investigated 1) release of histamine, leukotriene C4, and prostaglandin D2 from anti-immunoglobulin E (IgE)-stimulated basophils of adults with atopic dermatitis and unaffected individuals and 2) specific H3 receptor-dependent basophil mediator release, using an H3 receptor agonist and antagonist. Basophil-rich leukocyte fractions were prepared by dextran sedimentation of venous blood from 19 patients with atopic dermatitis (five male, 14 female, mean age 30.6 years, range 19-59 years) and 15 unaffected individuals (five male, 10 female, mean age 27.6 years, range 19-50 years). Anti-IgE (0.78-78.0 micrograms/ml) stimulation of basophils induced a concentration-dependent release of histamine and leukotriene C4, but not prostaglandin D2. Histamine release was maximally induced by 7.8 micrograms/ml anti-IgE with no significant (Mann-Whitney U test) difference between atopic basophils (n = 17; 43.65 +/- 4.16% mean +/- SEM) and normal basophils (n = 13; 52.23 +/- 4.39%). LTC4 release was maximal from atopic basophils incubated with 2.6 micrograms/ml anti-IgE (n = 5; 0.99 +/- 0.29 pg/10(6) cells) and from normal basophils incubated with 0.78 microgram/ml anti-IgE (n = 5; 25.38 +/- 5.79 pg/10(6) cells). Anti-IgE-stimulated release of leukotriene C4 from atopic basophils was significantly less than from normal basophils at all concentrations (p < 0.05). Basophils were co-incubated with anti-IgE (2.6 and 7.8 micrograms/ml) and either the H3 receptor agonist, (R)alpha-methylhistamine (10(-8) and 10(-7) M), or the H3 receptor antagonist thioperamide (10(-6) and 10(-5) M). Neither drug modulated anti-IgE-induced release of histamine (atopics, n = 10; normals, n = 8). These results indicate 1) that basophils from adults with atopic dermatitis release the same amount of histamine as, but less leukotriene C4 than, basophils of unaffected adults and 2) that H3 receptors are not involved in anti-IgE release of histamine from basophils. These data do not support a role for increased basophil release of histamine as a mediator in the itch and erythema of atopic dermatitis in adults.

The new H1 antihistamines are a major therapeutic advancement in the treatment of allergic disorders such as urticaria and allergic rhinitis. Their efficacy combined with greatly reduced sedating and anticholinergic side effects makes the new class of H1 antihistamines the first-line treatment in the management of urticaria and mild angioedema. The choice of a particular low-sedating H1 antihistamine depends on pharmacokinetic considerations, the severity of the problem (systemic steroids and epinephrine are the first-line treatment for severe angioedema), and the requirement for limiting the frequency of administration. The efficacy of the new H1 antihistamines in the treatment of itch due to atopic eczema and systemic disease remains uncertain, and further controlled clinical trials are needed to elucidate their possible role in these conditions.

It has previously been shown that the inherently tumour necrosis factor-alpha (TNF-alpha)-sensitive L929 murine fibroblast cell line becomes much more sensitive to the cytotoxic effect of this cytokine after exposure to Mycobacterium tuberculosis in culture. In this study it is now shown that normal human cells of types likely to be involved in tuberculous lesions are affected in a similar way. Growth of normal human fibroblasts is usually stimulated by TNF-alpha in vitro, but after exposure to M. tuberculosis or to extracts of this organism, these cells are killed rather than stimulated by subsequent exposure to TNF-alpha. Similarly, human endothelial cells become susceptible to doses to TNF-alpha which do not normally affect viability. Moreover this enhancement of sensitivity to TNF-alpha is not confined to its toxicity. Endothelial cells and HeLa cells exposed to M. tuberculosis express increased levels of ICAM-1 after subsequent exposure to TNF-alpha, implying synergy between the two stimuli. It is suggested that these effects contribute to the ability of M. tuberculosis to distort the normal protective role of TNF-alpha so that the cytokine becomes detrimental to the host.

1. The histamine receptor sub-types that are involved in the initiation and maintenance of prostacyclin (PGI2) release from human endothelial cells have been investigated. 2. Endothelial cells cultured from umbilical vein (HUVEC) were incubated with either histamine, the selective H1-receptor agonists, 2-methyl histamine (2-MeHA) or thiazolylethylamine (ThEA), the H1-agonist/H3-antagonist, beta-histidine (beta-His), the selective H2-agonist, dimaprit, the H2-agonist/H3-antagonist, impromidine, the selective H3-agonist, (R)alpha-methylhistamine ((R)alpha-MeHA) and the H3-antagonist, thioperamide. 3. The H1-agonists and the H3-agonist (R)alpha-MeHA induced a concentration (100 nM-1 mM) and time-dependent release of PGI2 as determined by radioimmunoassay for 6-keto-PGF1 alpha, but were less potent than histamine itself. The rank order of potency was the same following 30 min and 24 h incubation, i.e. histamine > ThEA > 2-MeHA >> beta-His > (R)alpha-MeHA. 4. Histamine and 2-MeHA (1 microM-1 mM), ThHEA (10 microM-1 mM) and (R)alpha-MeHA (1 mM), but not beta-His, induced a significantly greater increase in PGI2 release after 24 h incubation than after 30 min incubation (P < 0.05). 5. Neither the selective H2-agonist, dimaprit, nor the H2-agonist/H3-antagonist, impromidine alone induced release of PGI2. 6. The H1-antagonist, mepyramine (10 microM), abolished release of PGI2 induced by histamine, the H1-agonists and (R)alpha-MeHA but the H2-antagonist cimetidine (10 microM) and the H2/H3-antagonist, burimamide (10 microM) did not significantly modulate PGI2 release. 7. Although the H3-agonist (R)alphax-MeHA induced release of PGI2, it failed to modulate PGI2 release in the presence of histamine.8. Low concentrations of the H3-antagonist, thioperamide (100 nM) did not modulate histamine release of PGI2 at all but after 24 h incubation, thioperamide (10-4 M) partially reduced PGI2 release in the presence of histamine.9. These results indicate that PGI2 from HUVEC is initiated and maintained via histamine HI-receptor occupancy. There appears to be no involvement of either H2- or H3-receptors in this particular endothelial cell histaminergic response.

When injected into human skin, endothelin-1 produces intense vasoconstriction localized to the site of the injection, but this area of vasoconstriction is surrounded by vasodilatation which spreads several centimetres from the injection site. The vasodilatation induced by intradermal injection of endothelin-1 (63 pmol) into human skin is prevented by local anaesthetic. Pretreatment of human skin with capsaicin also inhibits this response. Pretreatment of subjects with the selective histamine H1-receptor antagonist cetirizine, 10 mg orally 4 h before intradermal injections, inhibited vasodilatation caused by the intradermal injection of histamine (750 pmol), endothelin-1 (63 pmol), and carbachol (750 pmol). Endothelin-1 (0.3-10 microM) and carbachol (1-30 microM) failed to induce histamine release from rat peritoneal mast cells. We conclude that the vasodilatation caused by intradermal injection of endothelin-1 into human skin is neurogenic and is probably mediated by neuropeptide-containing primary afferent neurones. Because neither carbachol nor endothelin-1 cause histamine release from mast cells, our data suggest that histamine release from mast cells at the effector end of the axon reflex is responsible for the carbachol- and endothelin-induced vasodilatation in human skin.

The action of histamine on human dermal microvascular endothelial cells and modulation of its effects by the cytokine interleukin-1 and the vasoactive neuropeptide substance P have been investigated. Histamine (10(-6)-10(-3) M) induces release of prostaglandin E2 in a concentration- and time-dependent manner. Prostaglandin E2 release is facilitated principally by histamine H1 receptors as the H1 receptor antagonist pyrilamine attenuates prostaglandin E2 release whereas the H2 receptor antagonist cimetidine only slightly reduces release. In contrast to other cells, the histamine/receptor interaction is not associated with increased intracellular accumulation of the cyclic nucleotides, cyclic AMP, or cyclic GMP. Interleukin-1 induces a concentration-dependent release of prostaglandin E2 following 24 h incubation. However, substance P does not increase release of prostaglandin E2 above baseline. In cells incubated with 1 U/ml human recombinant interleukin 1 alpha for 24 h prior to stimulation with histamine (10(-5)-10(-3) M) for 30 min, there is a significant potentiation of histamine-induced release of prostaglandin E2 (p less than 0.05). Using a solubilized cell sonicate prepared from human dermal microvascular endothelial cells incubated with 1 U/ml human recombinant interleukin 1 alpha for 24 h, conversion of exogenous arachidonic acid into prostaglandin E2 increased by 60.19 +/- 18.28%. Cycloheximide partially reduces the increased conversion but completely blocks interleukin-1-induced release of prostaglandin E2 from intact cells. Substance P does not potentiate histamine-induced release of prostaglandin E2 or increase arachidonic acid conversion. These results demonstrate that human dermal microvascular endothelial cells are responsive to histamine and that interleukin-1, but not substance P, can potentiate histamine-induced release of prostaglandin E2. Interleukin-1 appears to act, at least in part, by regulating the availability of free arachidonic acid. Interactions between histamine and interleukin-1 may be important in the modulation of inflammatory reactions in skin.

Most women with acne are found to have polycystic ovaries on high resolution pelvic ultrasonography, but most of these women do not manifest the other classical clinical characteristics of the polycystic ovary syndrome. We have compared the endocrinological profile of women with acne who were found to have polycystic ovaries with that of women with polycystic ovaries who presented to an endocrine clinic with hirsutes or non-dermatological manifestations of the polycystic-ovary syndrome. The group of women with acne had normal serum hormonal concentrations. Unlike other women with polycystic ovaries, they did not have significantly elevated serum concentrations of luteinizing hormone or testosterone. By clinical and endocrinological criteria, patients with acne who have polycystic ovaries appear to be a distinct sub-population of women with polycystic ovaries.

Endothelin-1 (ET-1), a potent vasoconstrictor peptide, has been implicated in the maintenance of systemic and peripheral vascular tone. We have therefore sought direct evidence of a role for ET-1 in the regulation of blood flow and vascular tone in the human cutaneous microvasculature. Immunostaining for ET-1 was observed in all cutaneous blood vessels of normal human skin including the capillaries of the dermal papillae. Autoradiography showed specific binding of 125I-ET-1 over capillaries and larger blood vessels as well as hair follicles and sweat glands. In situ hybridization with a 32P-labeled RNA probe for ET-1 demonstrated mRNA for ET-1 in cultured human dermal microvascular endothelial cells (HDMEC). In HDMEC, basal release of PGE2 was significantly attenuated by ET-1 (100 pM-100 nM) (p less than 0.05, n = 7) with maximum inhibition in cells incubated with 10 nM ET-1. ET-1 also increased intracellular cAMP in a dose-dependent manner with a significant increase in HDMEC incubated with 100 nM ET-1 (p less than 0.05, n = 4). In HDMEC incubated with 100 nM ET-1, inhibition of PGE2 release was unaffected by the dihydropyridine Ca++ channel antagonist nifedipine or the extracellular Ca++ chelator EGTA, whereas the intracellular Ca++ chelator TMB-8 partially blocked the action of ET-1. In contrast, cAMP accumulation was significantly attenuated by EGTA (p less than 0.05, n = 4), nifedipine (p less than 0.05, n = 4), and TMB-8 (p less than 0.05, n = 4), indicating that the endothelial cell responses to ET-1 are complex and appear to involve both Ca(++)-sensitive and -insensitive pathways. These results provide evidence of an autocrine/paracrine role for ET-1 in the human cutaneous microvasculature.

Blood mononuclear cells (MNC) from patients with psoriasis were more adherent to monolayers of endothelial cells prepared from human umbilical cord vein than otherwise similar cells from control subjects. This increase in adherence occurred in the presence (mean 37% increase; p less than 0.01) and absence (mean 47% increase; p less than 0.05) of 10% autologous serum and was not related to the disease severity of the patients. The augmented adhesiveness of the patients' cells was also apparent when using monolayers of endothelial cells isolated from human skin. The levels of immune complexes, complement, alpha 2-macroglobulin, acute phase proteins (alpha 1-acid glycoprotein, C-reactive protein and alpha 1-antitrypsin), and tumor necrosis factor alpha (TNF alpha), interleukin-1 alpha (IL-1 alpha), and interleukin-1 beta (IL-1 beta) in the patients' sera were within normal limits. When MNC were added to endothelial monolayers that had been incubated with either TNF alpha or the highest concentration of rIL-1 beta used in the study, both the patients' and control's cells exhibited a similar increase in attachment (p less than 0.01). Pretreatment of endothelium with interferon-gamma did not enhance the attachment of MNC from either group of subjects. The augmented adherence of the patient's MNC appears to be due to an abnormal adhesiveness of the lymphocytes rather than the monocytes and is not related to an enhanced expression of the cell-surface adhesion molecules CD11a/CD18. It is likely that the circulating MNC of psoriatic patients may be predisposed for extravasation into skin.

Image analysis quantification was used to assess the results of immunocytochemistry for a neuronal marker and neuropeptides in digital skin biopsies from Raynaud's phenomenon (RP) and systemic sclerosis (SS) patients, to verify the possibility of a selective quantitative abnormality of immunoreactive nerves. The field area of specific immunostaining and nerve counts were evaluated on coded specimens, and the data compared by statistical analysis. Nerves immunoreactive for protein gene product 9.5 (PGP), a marker for neuronal elements, were decreased significantly in epidermal and subepidermal layers of digital skin in RP patients (P less than 0.0001). This change was paralleled by a decrease of calcitonin gene-related peptide (CGRP) immunoreactive nerves in the epidermis and around capillaries in the dermal papillae (P = 0.005). In the skin of RP patients, these changes were readily demonstrated by image analysis, although they were not always apparent on visual screening. In digital skin of SS patients, there was a generalized and very significant decrease of PGP, CGRP, and VIP immunoreactivities in all areas (P less than 0.0001). These results demonstrate that neuropeptide-containing nerves are involved in the digital pathology of RP and SS, and that image analysis quantification is an accurate and sensitive method for assessing morphological changes in pathological samples.

A defective histaminergic dilating system in the digital vasculature has been proposed for the pathophysiology of Raynaud's phenomenon but this is not supported by studies of digital intradermal responses to histamine or agents which cause histamine release. The vascular responses (measured by planimetry and laser Doppler flowmetry) of digital skin over the middle phalanx to intradermal histamine, compound 48/80 and Substance P have now been studied at low temperatures (because it is in the cold that Raynaud's phenomenon occurs) in normal controls and patients with primary Raynaud's phenomenon. A cold-related attenuation of mast cell histamine release by compound 48/80 was observed in both normal and Raynaud's subjects. These results do not support a major histaminergic defect in the pathogenesis of Raynaud's phenomenon.

Peptides released from sensory nerves during an axon reflex are thought to cause mast cell degranulation, histamine (Hi) release and Hi-induced vasodilatation leading to the flare of the triple response. Capsaicin stimulates peptide release from sensory neurones and causes flare in vivo but does not cause Hi release from mast cells in vitro. The effects of capsaicin on mast cell degranulation in human skin in vivo has been studied by histological examination of skin biopsies after topical capsicin (1%) treatment of stratum corneum-denuded forearm in four volunteers. The results show a significant reduction in the visible numbers of mast cells and the appearance of degranulated mast cells ghosts in the skin six hours after capsaicin application. Since capsaicin itself does not release Hi from mast cells, these data suggest that capsaicin-induced release of peptides from neurones could cause mast cell degranulation.

The pathophysiology of Raynaud's phenomenon is not well defined, but active cutaneous microvascular vasoconstriction and emptying must occur to account for the pallor and are reasons for studying the microvasculature. It has been proposed that there may be a defect in a local histamine vasodilator mechanism. The role of the peptidergic nervous system in Raynaud's phenomenon has not been previously investigated. To study the histaminergic and peptidergic axes in Raynaud's phenomenon, we measured the cutaneous microvascular responses of patients with Raynaud's phenomenon to digital intradermal injections of saline, histamine, the histamine-releasing agent, compound 48/80, substance P, and calcitonin gene-related peptide. We compared these results with those obtained in normal subjects. Intradermal cutaneous microvascular blood flow responses were quantified by planimetry and laser Doppler flowmetry. The results show: a) that in primary Raynaud's phenomenon there is no evidence of local deficiency in histamine release or insensitivity to histamine in the cutaneous microvasculature; and b) that patients with Raynaud's phenomenon react normally to the neuropeptides calcitonin gene-related peptide and substance P, providing a rationale for treating Raynaud's phenomenon with vasoactive peptides.

Transforming growth factor alpha (TGF alpha) is a keratinocyte-growth-stimulating factor which may have a role in epidermal hyperproliferation, psoriasis, and wound healing. Since increased epidermal proliferation occurs in response to UV radiation, we have measured the amount of TGF alpha in exudates from normal and UVB-irradiated human skin. Cutaneous exudates were obtained using the skin chamber abrasion technique from one side of the back of volunteers (n = 10) with normal skin (collected following skin contact times of 2 and 30 min). Exudates were similarly obtained from the contralateral side of the back at sites irradiated 2 h previously with 3 x the minimum erythemal dose UVB. Levels of TGF alpha were measured by radioimmunoassay. Normal human skin released TGF alpha immediately after abrasion: unirradiated, 63 +/- 18 ng/ml; irradiated, 89 +/- 15 ng/ml. Levels of TGF alpha increased within 30 min to 110 +/- 14 ng/ml in unirradiated skin and to 190 +/- 17 ng/ml in irradiated skin. Irradiated sites at 30-min time points were significantly higher (p less than 0.05) than all other samples. The presence of releasable TGF alpha in normal skin suggests a role for TGF alpha in wound repair mechanisms.

During an open prospective study of the synthetic retinoid isotretinoin in ten patients with systemic sclerosis, one patient developed an eosinophilic pleural effusion and two patients were noticed to have asymptomatic deterioration in pulmonary function tests. The pulmonary function of all treated patients was then compared retrospectively with a similar control group of patients not treated with isotretinoin. There was a significantly greater decrease in the 1-s forced expiratory volume and transfer coefficient in the patients with systemic sclerosis being treated with isotretinoin in comparison to the untreated control patients. Studies of lung function in patients treated with isotretinoin for other indications are required.

The morphological distribution of endothelin-1 (ET-1) was investigated in human digital skin biopsies by immunohistochemistry using endothelin antisera, and by in vitro autoradiographic binding studies with 125I-labeled ET-1. In vitro studies on the responsiveness of cutaneous microvascular endothelium were carried out using human dermal microvascular endothelial cells (HDMEC) cultured from neonatal foreskin. Endothelin immunoreactivity was present in the endothelial cells of cutaneous blood vessels, in large and small arteries, veins in the dermis and capillaries, including those of the dermal papillae. Autoradiographic studies showed the presence of 125I-labeled ET-1 binding sites on the blood vessels and sweat glands. In confluent monolayers of HDMEC, ET-1 (100 pM-100 nM) significantly inhibited basal release of prostaglandin E2 (PGE2) (p less than 0.05), while causing a dose-dependent increase of intracellular cyclic adenosine monophosphate (cAMP) levels. cAMP accumulation, induced by 100 nM ET-1, was blocked by extracellular Ca2+ chelator EGTA, the intracellular Ca2+ chelator TMB-8, and dihydropyridine Ca(2+)-channel antagonist nifedipine (p less than 0.05), whereas ET-1 inhibition of PGE2 release was unaffected. These findings indicate that ET-1 may be important in the control of blood flow and vascular tone in the cutaneous microvasculature.