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Biomedical subjects

S Shuster

Publications and source records attributed to S Shuster.

At least 127 records · Page 7Linked to original sources
PubMed1985

A comparison of astemizole and chlorpheniramine in dermographic urticaria.

The effects of the H I receptor antagonists astemizole and chlorpheniramine on dermographism were compared in a double-blind study in sixteen patients. Both drugs resulted in a parallel and significant depression of the dermographic force-response curve and an elevation of the weal-force threshold, but the changes were greater in the patients receiving astemizole (a maximal potency shift of 74% for astemizole and 37% for chlorpheniramine). Subjective itch (10 cm line) and frequency of dermographic episodes were also reduced more by astemizole than by chlorpheniramine. The effect of astemizole was greater at 4 weeks than at 2 weeks, whereas the effect of chlorpheniramine had decreased at 4 weeks. The effect of astemizole but not chlorpheniramine was still apparent 4 weeks after treatment had been stopped. Since the degree of residual dermographism was comparable despite great differences in histamine weal inhibition a vasoactive mechanism in addition to that mediated by histamine must be involved in dermographic urticaria.

Adolescent↗
PubMed1985

Etretinate in pustular psoriasis of palms and soles.

In a double-blind controlled study of patients with pustular psoriasis of palms and soles who were allocated at random to etretinate or placebo, we found that etretinate improved the condition as assessed by pustule count and overall clinical response. Side-effects occurred but were accepted by the patients in the short-term. The clinical usefulness of etretinate in this condition will depend on time to relapse, and whether this can be prevented or postponed by continuous treatment. Toxicity in the long-term will also be important.

Adult↗
PubMed1985

Distribution and sub-cellular localization of drug metabolizing enzymes in the skin.

The distribution and sub-cellular localization of cytochrome P-450-dependent mono-oxygenase activity in the skin of adult hairless mice has been investigated using ethoxycoumarin, ethoxyresorufin and benzpyrene as substrates. Highest levels of mono-oxygenase activity per unit area of skin were found in the dermis, both before and after induction with benzanthracene. Subcellularly, mono-oxygenase activity was predominantly microsomal and, prior to induction, located entirely in the smooth microsomal fraction.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1985

Antipyrine clearance and alpha 1-acid glycoprotein levels after isotretinoin.

Eight male subjects aged 18-24 years were treated with 0.5 mg of isotretinoin day-1 kg-1. After 4 weeks levels of cholesterol (P less than 0.05) and triglyceride (P less than 0.05) were increased and levels of high-density lipoprotein (HDL)-cholesterol were decreased (P less than 0.05). Concentrations of aspartate aminotransferase (P less than 0.01) and gamma-glutamyltranspeptidase (P less than 0.01) were higher after treatment; increased alkaline phosphatase and a reduction in bilirubin levels did not reach statistical significance. Values for thyroxine were reduced after isotretinoin and free thyroxine index was lower (P less than 0.01). Measurements of salivary clearance of antipyrine and levels of alpha 1-acid glycoprotein were lower after treatment but these differences did not reach statistical significance. The findings suggest that there is a small decrease in hepatic microsomal-enzyme activity after isotretinoin and that the unwanted effects on lipids, liver and thyroid function are unlikely to be due to hepatic microsomal-enzyme induction.

Acne Vulgaris↗
PubMed1985

Minimal effect of complete H1 receptor blockade on urticaria pigmentosa.

The effect of complete H1 receptor blockade on urticaria pigmentosa was studied in 6 patients. Astemizole 10 mg tds was given for 6 weeks to achieve complete H1 receptor blockade and the response measured by change in force-weal response measurements using two different forces on a dermographic stylus and measuring response as weal diameter. Weal and flare reactions to 8 micrograms histamine were completely abolished by the astemizole but dermographic weal-force responses were reduced only by 12-15% indicating that histamine acting at the H1 receptor plays only a small part in the wealing of urticaria pigmentosa.

Adult↗
PubMed1985

Susceptibility and amplification of sensitivity in contact dermatitis.

We have examined the hypothesis that people who develop contact allergies to environmental substances do so because they have heightened susceptibility. Analysis of data from 2200 consecutive patients tested with the 20 commonest antigens in a patch-test clinic showed that more people developed multiple contact allergies than would be predicted from the frequency of single allergies; the excess was too great to be explained by chance and increased with number and rarity of the combinations of sensitizers. The possibility that this was due to enhanced individual susceptibility to sensitization rather than concomitant exposure to several sensitizers was confirmed by showing that patients with multiple allergies are more readily sensitized experimentally, and to a greater degree than normal, by dinitrochlorobenzene (DNCB), an unrelated antigen. The defect involves induction rather than expression of sensitivity. Amplification of the response to DNCB is proportional to susceptibility (calculated from the ratio of observed prevalence of multiple allergies to that predicted from the prevalence of single allergies) throughout the range from normal subjects, through those with a single sensitivity, to those with rare, multiple allergies. Therefore, we conclude that individual susceptibility is an important factor in the development of contact dermatitis, and occurs by a non-antigen-specific amplification of immune sensitization.

Adult↗
PubMed1984

Effects of isotretinoin on serum lipids and lipoproteins, liver and thyroid function.

Seven patients with severe rosacea were treated with 1 mg/kg per day isotretinoin for 12 wk. There were significant increases in serum triglyceride (p less than 0.001) and cholesterol (p less than 0.001). Triglyceride associated with very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) increased (p less than 0.01), cholesterol in VLDL and LDL increased (p less than 0.01), and levels of HDL cholesterol decreased (p less than 0.01). There were changes in indices of liver function, with increased levels of gamma-glutamyltransferase (GGT) (p less than 0.01), alkaline phosphatase (ALP) (p less than 0.01) and aspartate aminotransferase (AST) (p less than 0.01), and decreased bilirubin levels (p less than 0.05). Although levels of thyroxine and triiodothyronine were lower after treatment (p less than 0.05), there were no changes in basal levels of thyroid-stimulating hormone (TSH), luteinizing hormone (LH) or follicle-stimulating hormone (FSH), and responses to thyrotrophin releasing hormone (TRH) and luteinizing hormone releasing hormone (LHRH) were unchanged. These changes may partially be explained by induction of hepatic microsomal enzymes by isotretinoin.

Adult↗
PubMed1984

Inhibition of dithranol inflammation by free-radical scavengers.

Dithranol (anthralin) inflammation of forearm skin was completely inhibited by various scavengers of free radicals of the oxygen species. It is concluded that dithranol inflammation is initiated by formation of free radicals; these may act through lipid peroxidation and production of inflammatory endoperoxides or by a more direct mechanism.

Administration, Topical↗
PubMed1984

Induction of drug metabolising enzymes in the skin by topical steroids.

The effects of the topical application of glucocorticoid steroid creams used in clinical practice, on the activity of drug metabolising enzymes in the skin of adult hairless mice has been investigated. Treatment with hydrocortisone and fluandrenolone had no effect on the activity of ethoxycoumarin O'dealkylase (EOD) in the skin whereas all other fluorinated synthetic glucocorticoids tested, significantly induced cutaneous EOD activity. Fluincinolone acetonide, Fluincinonide , and Betamethasone Valertate increased enzyme activity 2-3-fold, and clobetasol propionate induced enzyme activity 6-fold. The ability of each steroid preparation to induce enzyme activity was related to its clinical potency, and induction of enzyme activity by clobetasol propionate was maximal at 0.05%, the concentration used in clinical practice. The effects of clobetasol propionate on cutaneous ethoxycoumarin and ethoxyresorufin dealkylase activities were different from those produced by 3 methycholanthrene , indicating that glucocorticoids may represent a class of inducing agents with different properties from the polycyclic hydrocarbons.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1984

Characterization and quantification of epidermal and dermal glucocorticoid receptors in the rat.

The interaction between [3H]triamcinolone acetonide and cytosol proteins was studied in separated epidermis and dermis of neonatal rats. Both tissues possessed a binding site with a high affinity (dissociation constant = 0.2 nM) and a low capacity (150-220 fmol/mg protein) for triamcinolone acetonide. The binding site in each tissue cytosol was inactivated by heating at 37 degrees C or by incubating with either trypsin, Triton X-100 or NaCl. The second-order rate constant of association was 1.99 X 10(6)M-1min-1 for the epidermal, and 1.65 X 10(6)M-1min-1 for the dermal receptor binding site. Quantitatively there was a difference between the two tissues with 82% of the receptor being found in the dermis and 18% in the epidermis.

Animals↗
PubMed1984

Reduction of antipyrine clearance in psoriasis.

Antipyrine clearance was determined in 41 psoriatics and age-sex matched controls, using sequential measurements of salivary concentration. Antipyrine clearance and elimination rate constant were less in psoriatics (P less than 0.05) and apparent volumes of distribution were similar. These differences were greater between female psoriatics and controls (P less than 0.025; P less than 0.05) and the differences between male psoriatics and controls were not significant. Correlation of simultaneous measurements of saliva and plasma antipyrine concentration in six psoriatics and age-sex matched controls showed no differences between the two groups. We conclude that antipyrine clearance is reduced in psoriasis but the underlying mechanism is unclear.

Adolescent↗