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Biomedical subjects

R H Meyrick Thomas

Publications and source records attributed to R H Meyrick Thomas.

At least 19 recordsLinked to original sources
PubMed1988

Lichen sclerosus et atrophicus and autoimmunity--a study of 350 women.

A study of autoimmune related phenomena in 350 women with histologically confirmed lichen sclerosus et atrophicus revealed that 21.5% had one or more autoimmune related diseases, 21% had one or more first degree relatives with an autoimmune-related disease, 42% had an autoantibody at a titre greater than 1:20, and 59.5% had one or more of these autoimmune-related phenomena. No statistically significant differences in the natural history of lichen sclerosus et atrophicus were demonstrated between those patients with autoimmune-related phenomena and those without.

Adolescent↗
PubMed1988

Pharmacokinetics of small doses of methotrexate in patients with psoriasis.

The pharmacokinetics of methotrexate was studied in 23 patients with chronic plaque psoriasis. Ten patients received a single oral does and 13 patients a single intramuscular injection of 25 mg methotrexate. Serum methotrexate was measured for 24 hours following administration of the drug using a magnetizable solid-phase radio-immunoassay. The disappearance of methotrexate from the serum fitted a two-compartment model with a distribution phase half-life of 1.18 +/- 0.12 h and an elimination phase half-life of 5.35 +/- 0.62 h following the oral dose and 1.45 +/- 0.22 h and 4.71 +/- 0.32 h, respectively following the intramuscular dose. Peak serum methotrexate concentrations varied greatly between patients but the mean area below the curve for the two routes of administration did not differ significantly. In a further 18 psoriatic patients receiving long-term maintenance methotrexate therapy there was no consistent relationship between salivary and serum methotrexate levels.

Administration, Oral↗
PubMed1987

Nifedipine in the treatment of Raynaud's phenomenon in patients with systemic sclerosis.

A double-blind, placebo-controlled, cross-over trial of nifedipine 10 mg three times daily for 6 weeks, in 10 patients with Raynaud's phenomenon secondary to systemic sclerosis, is reported. A significant reduction in the duration of attacks of Raynaud's phenomenon was observed. Nifedipine therapy also reduced the number and severity of attacks of Raynaud's phenomenon and the development of new digital ulcers, and increased the digital blood flow, but none of these changes was statistically significant. No alteration in red blood cell deformability or leukocyte chemiluminescence was observed during nifedipine treatment.

Blood Flow Velocity↗
PubMed1986

Increased chemiluminescence of polymorphonuclear leucocytes from patients with progressive systemic sclerosis.

Chemiluminescence (CL) of whole blood and isolated polymorphonuclear leucocytes (PMN) from patients with systemic sclerosis (SS) and from age and sex matched controls was measured. CL was induced by the addition of particles (zymosan, latex beads), or phorbol myristate acetate (PMA) or chemotactic peptide (FMLP). Whole blood CL (induced by PMA, zymosan or latex particles) was significantly greater in SS patients than in normal controls. Isolated PMN CL (induced by PMA, FMLP or latex particles) was also significantly greater in the SS patients compared with controls. Increased CL or PMN from patients with SS was mainly observed when luminol was used as amplifier (which detects hydrogen peroxide formation). In most cases, lucigenin-amplified CL of PMN from patients with SS (which detects the primary superoxide anion radical formation) did not differ from the controls. Sera from patients with SS significantly increased both spontaneous and induced CL of normal PMN. Enhanced excitability of PMN to phagocytosis-related stimuli may provide a mechanism for the (leucocyte-mediated) endothelial injury in SS.

Female↗
PubMed1986

The development of lichen sclerosus et atrophicus in monozygotic twin girls.

The development of vulval lichen sclerosus et atrophicus in monozygotic twins is described. This is the first report of the occurrence of lichen sclerosus et atrophicus in two genetically identical individuals, and is considered to provide further evidence that inherited factors are of relevance in the aetiology of this disorder.

Child, Preschool↗
PubMed1986

Collagen and elastin changes in D-penicillamine-induced pseudoxanthoma elasticum-like skin.

A patient with cystinuria who was treated with large doses of D-penicillamine for 19 years developed skin abnormalities resembling those seen in pseudoxanthoma elasticum. Biochemical and histological examination of the dermis showed that the collagen content, the ratio of the major genetic forms of collagen and the distribution of collagen types was normal. Light microscopy demonstrated the presence of vastly increased amounts of elastin in the dermis, and the individual elastin fibres were shown by electron microscopy to be abnormal; chemical analysis showed the elastin to be poorly cross-linked. Some of the collagen also appeared structurally abnormal, and biochemically resembled that seen in the dermis of a young child with respect to cross-linking and hexosyl-lysine content. The therapy led to an increased deposition of collagen and elastin fibres which appeared abnormal, and resulted in an increase in total skin surface area. These data indicate that D-penicillamine was not fully effective in inhibiting collagen and elastin cross-linking, and appeared to prevent or inhibit the natural maturation process of the collagen.

Aged↗
PubMed1985

The effect of ranitidine, alone and in combination with clemastine, on allergen-induced cutaneous wheal-and-flare reactions in human skin.

The effect of intradermal ranitidine (administered alone and in combination with clemastine) on allergen-mediated wheal-and-flare reactions has been evaluated in a double-blind study on 10 healthy atopic volunteers. Ranitidine alone, administered in doses over a 10(4)-fold concentration range, had no effect on the size either of allergen-induced wheal or flare reactions. Clemastine alone evoked a dose-related inhibition of both wheal and flare. Compared to the inhibition achieved by clemastine alone, the combination of ranitidine with clemastine produced a small but significant increase in inhibition of allergen-induced flare at ranitidine concentrations of 10(-5) mol/L (p less than 0.001) and 10(-6) mol/L (p less than 0.01), and of allergen-induced wheal at ranitidine concentration 10(-5) mol/L (p less than 0.01). Our results provide further evidence for the presence of cutaneous histamine H2 receptors and their participation in the formation of allergen-mediated skin reactions but indicate that the contribution of cutaneous histamine H2-receptor stimulation to the production of immediate wheal-and-flare reactions evoked by allergen is only modest.

Adolescent↗
PubMed1985

Oral acyclovir in the suppression of recurrent non-genital herpes simplex virus infection.

In a double-blind, placebo-controlled, cross-over trial in 11 patients suffering eight or more episodes of recurrent non-genital herpes simplex virus (HSV) infection per annum, only two patients experienced a recurrence during treatment with oral acyclovir (200 mg 4 times daily) for up to 12 weeks, compared with nine during placebo treatment (P = 0.016). Although lesion development was effectively suppressed in nine of the patients whilst taking acyclovir, the development of prodromal symptoms, and occasionally erythema, was reported by five. There was no difference between acyclovir and placebo in the time to the next recurrence following completion of treatment. No patient reported any side effects of either placebo or acyclovir therapy. It is believed that this is the first report of any form of oral therapy which is effective in suppressing recurrent non-genital HSV infection in immunocompetent patients.

Acyclovir↗
PubMed1983

A comparison of the in vivo effects of ketotifen, clemastine, chlorpheniramine and sodium cromoglycate on histamine and allergen induced weals in human skin.

The effect of ketotifen was compared with that of clemastine and chlorpheniramine, known antihistamines, and sodium cromoglycate, a drug considered to have mast cell "stabilizing' properties on histamine and allergen wealing reactions in human skin, in random order, double-blind, placebo controlled studies. Ketotifen was significantly more potent in the inhibition of both histamine (P less than 0.001) and allergen (P less than 0.001) skin wealing reactions than either clemastine or chlorpheniramine. Sodium cromoglycate had no significant effect on either histamine or allergen skin wealing reactions in any of the concentrations tested. However ketotifen, like clemastine, had a significantly greater inhibitory effect on histamine than on allergen induced weals (P less than 0.001) and both drugs were shown to act as competitive antagonists of histamine. Ketotifen has been shown to be a potent anti-histamine but there is no evidence from these in vivo studies to suggest that it has any additional inhibitory activity on release of mediators from mast cells in human skin.

Allergens↗