Serotonergic agonists stimulate inositol lipid metabolism in rabbit platelets

The metabolism of inositol phospholipids in response to serotonergic agonists was investigated in rabbit platelets. In platelets prelabelled with [3H]-inositol, in a medium containing 10 mM LiCl which blocks the enzyme inositol-1-phosphatase, 5-hydroxytryptamine (5-HT) caused a dose-dependent accumulation of inositol phosphates (IP). This suggests a phospholipase-C-mediated breakdown of phosphoinositides. Ketanserin, a selective 5-HT2 antagonist, was a potent inhibitor of the 5-HT response, with a Ki of 28 nM, indicating that 5-HT is activating receptors of the 5-HT2 type in the platelet. Lysergic acid diethylamide (LSD) and quipazine also caused dose-related increases in inositol phosphate levels, though these were considerably less than those produced by 5-HT. These results show that relatively small changes in phosphoinositide metabolism induced by serotonergic agonists can be investigated in the rabbit platelet, and this cell may therefore be a useful model for the study of some 5-HT receptors.

A comparison of pulsed ultrasound, radiography and micrometer screw gauge in the measurement of skin thickness

Comparisons of ultrasonic, radiographic and micrometer methods in the measurement of skin thickness were made in 16 volunteers before and after 1-month's treatment with four clobetasol propionate formulations. Correlations between the methods were highly significant (r = 0.68 to 0.75). Correlations in the females were better than in the males suggesting that measurements in women are more easily made. Percentage reductions in skin thickness after steroid treatment were ranked in an identical order, whichever method was used. Each of the three methods, therefore, was shown to be effective. Ultrasound was the preferred technique but the micrometer screw gauge was shown to be a reasonable alternative.

Enhanced release of inflammatory mediators from lithium-stimulated neutrophils in psoriasis

We have used lithium salts to stimulate degranulation in order to assess neutrophil activity in psoriasis. Evidence is presented for significant enhancement of degranulation of beta-glucuronidase (primary granules) and vitamin B12-binding protein (secondary granules) from lithium-stimulated neutrophils in psoriatic whole blood. Basal levels of granule markers showed no significant difference between normal and psoriatic neutrophils. On the other hand, enzymes associated with neutrophil function (myeloperoxidase and catalase) were found to be markedly increased in resting psoriatic neutrophils.

Influence of lithium and fluoride on degranulation from human neutrophils in vitro

We have demonstrated that degranulation from normal human neutrophils in whole blood was stimulated by low concentrations of lithium salts and was produced by noncytolytic means. Significant amounts of beta-glucuronidase could be released from the primary granules, in addition to vitamin B12- binding protein from the secondary granules, by 10 mM lithium. Release was almost totally inhibited by 1 mM fluoride, under the same conditions. There was no release of lactate dehydrogenase and no loss of viability of cells incubated in either lithium or fluoride at the concentrations used. Lithium was also observed to have no effect on reactive oxygen production by phagocytic stimulation of isolated neutrophils. In addition, lithium and fluoride were shown to manipulate the intracellular levels of cAMP. The results demonstrated a direct effect of lithium on release of inflammatory mediators from neutrophils in vitro. The methods used also provide a simple and effective test to study an important function of neutrophil activity and can be used to evaluate degranulation in a number of clinical conditions.

Treatment of chronic plaque psoriasis with dithranol and urea creams: a double-blind study

Stable cream formulations containing 0.1% or 0.2% dithranol in a 17% urea base have been developed. A double-blind comparative trial in 20 out-patients showed that over a 6-week treatment period the 0.2% dithranol and urea cream was significantly more effective (p less than 0.01) than the 0.1% dithranol and urea cream in clearing chronic plaque psoriasis. The 0.2% dithranol/urea cream was accompanied by a higher incidence of minor, irritant side-effects, but was still well accepted by patients for use at home. The availability of differing strengths of dithranol and urea cream enables practitioners to tailor dithranol treatment in accordance with the individual patient's clinical response.

Chattanooga's experience with reorganization for delivery of health services

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