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Biomedical subjects

C B Bunker

Publications and source records attributed to C B Bunker.

At least 91 records · Page 5Linked to original sources
PubMed1996

Calcitonin gene-related peptide, endothelin-1, the cutaneous microvasculature and Raynaud's phenomenon.

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.

Adult↗
PubMed1996

Staphylococcal scalded skin syndrome in an HIV-1 seropositive man.

The staphylococcal scalded skin syndrome (SSSS) is very rare in adults. Renal impairment and immunocompromise are predisposing causes. We report a 38-year-old HIV-1 seropositive intravenous drug abuser who developed SSSS due to staphylococcal pneumonia. An exfoliating toxin-releasing Staphylococcus aureus, phage type II type 3C, was isolated from the sputum and from blood cultures. This is the third case of adult SSSS to be reported in the context of HIV disease.

AIDS-Related Opportunistic Infections↗
PubMed1996

Successful treatment of a patient with octreotide-resistant necrolytic migratory erythema.

We report a patient with the glucagonoma syndrome and octreotide-resistant necrolytic migratory erythema (NME). The NME responded on two occasions to an intravenous infusion of essential fatty acids (EFA) and amino acids (AA). A deficit of serum EFA prior to treatment was corrected following the infusion, whilst plasma AA were low before and after treatment. These findings indicate that NME, in the glucagonoma syndrome, may respond to correction of the EFA deficit, and that NME may be a disease of EFA deficiency.

Amino Acids↗
PubMed1996

Scleredema diabeticorum of Buschke confined to the thighs.

We describe a patient with insulin-dependent diabetes without vascular complications in whom scleredema was confined to the thighs. Electron microscopy demonstrated heterogeneity in both the size and density of the collagen fibrils and the presence of filamentous material between them.

Adult↗
PubMed1996

Ectopic cutaneous schistosomiasis: extragenital involvement with progressive upward spread.

The ectopic deposition of ova of Schistosoma haematobium within the dermis is very rare, even in countries where infection with this trematode is widespread. When it does occur, it usually affects the genital area. We report a patient who developed ectopic genital and extragenital cutaneous involvement 4 months after swimming in Lake Malawi. The lesions appeared sequentially and spread from the genitalia in a caudocephalic manner. Doppler imaging of the pelvic veins did not reveal any anomalous venous drainage to account for the distribution of these lesions.

Adult↗
PubMed1996

Cutaneous lymphocytic vasculitis in acute myeloid leukaemia.

We report a 63-year-old woman who presented with an 8-week history of widespread indurated, purpuric lesions associated with weight loss of 7 kg and several episodes of epistaxis. A skin biopsy demonstrated a lymphocytic vasculitis with haemorrhage and parakeratosis. A blood film and bone marrow examination showed features of a myelodysplastic syndrome in transformation to acute myeloid leukaemia. Leucocytoclastic vasculitis and polyarteritis nodosa occur in association with acute myeloid leukaemia, but the association with lymphocytic vasculitis is new.

Acute Disease↗
PubMed1994

Localized trichorrhexis nodosa.

Trichorrhexis nodosa is a disorder of the hair shaft in which there is a distinctive response to injury. The hair is fragile and on examination regularly spaced pale 'node-like' swellings may be observed. It may affect normal hair following excessive or repeated trauma, or may occur after minimal trauma if there is an inherent defect in keratin synthesis causing abnormally brittle hair. The diagnosis can be readily made clinically and confirmed microscopically. Treatment is aimed at reducing trauma. We describe a case of localized trichorrhexis nodosa in a patient with otherwise apparently normal hair.

Adult↗
PubMed1994

Cutaneous nerve fibre depletion in vibration white finger.

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)

Action Potentials↗
PubMed1993

Calcitonin gene-related peptide in treatment of severe peripheral vascular insufficiency in Raynaud's phenomenon.

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.

Adult↗
PubMed1993

Characterization of endothelin-binding sites in human skin and their regulation in primary Raynaud's phenomenon and systemic sclerosis.

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.

Adult↗
PubMed1993

Basophil mediator release in atopic dermatitis.

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.

Adult↗