Thirty-eight cases of lentigo maligna and 22 cases of lentigo maligna melanoma, were reviewed in order to compare cure rates of various methods of treatment. Surgical excision resulted in the best cure rate (91%); destructive modalities were less successful (45%). All lesions treated with 5% 5-fluorouracil recurred.

For primary tumors without evidence of organ metastases, surgical excision should be the primary therapy. Owing to the high rate of local metastases, a safety margin of at least 2 cm should be considered. In situations where small, localized tumors and/or special locations necessitate a smaller safety margin, compensation by complete histological examination of the excision margins and perhaps adjuvant radiation therapy should be undertaken. The literature states that benefits of Mohs micrographic surgery (over wide local excision) include tissue conservation and identification of tumors that may require extremely wide excision margins. The majority of data to date supports the use of Mohs surgery in the treatment of Merkel cell carcinoma.

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1969. The effect of vasodilator drugs on the noradrenaline constrictor response in the isolated mesenteric artery. Can. J. Physiol. Pharmacol. 47,[663][664][665][666][667][668][669] Previous reports have indicated that diazoxide will inhibit the vasoconstrictor response to noradrenaaine on isolated aortic strips (Wohl et al. Life Sci-7,381 (1968)). Inhibition of the noradrenaaine response was dependent on the calcium concentrations. The present study has confirmed this observation in an isolated perfused rnesenteric artery preparation. In addition, a calcium-dependent inhibition of the raoradrena8ine constrictor response was found with theophylline and sodiuna nitrite but isoproterenol did not inhibit the noradrenaline response. It is suggested that the drugs which inhibit noradrenaline rnay do so by either blocking calcium receptors or by depleting an intracellular calcium pool necessary for drug-induced vasoconstriction; or by preventing calcium release from such a pool. Blockade of alpha adrenergic receptors is probably not involved since the drugs also blocked the constrictor response to vasopressin. The mecha~aisrn of the inhibitory action of these drugs is probably not related to their effects on cyclic AMP.The methylated xanthine theophylline is known to produce a number of effects which are qualitatively similar to the beta effects of the adrenergic amines. For example, both groups of drugs can produce positive inotropic and chronotropic effects and vasodilation. In addition, both methylated xanthines and catecholamines can increase tissue levels of adenosine-3',5~-monophosphate (cyclic AMP), a nucleotide postulated to act as a second messenger mediating a variety of hormonal effects (Sutherland et al. 1968). Theophylline can increase the amount of cyclic AMP by inhibiting phosphodiesterase, the enzyme responsible for metabolism of the nucleotide (Butcher and Sutherland B 962) whereas catechollarnincs increase the amount of cyclic AMP by increasing the synthesis of the compound (see Sutherland et al. 1968). If both groups of drugs produce their cffects by increasing cyclic AMP levels, one by increasing synthesis and the other by decreasing the destruction of the nucleotide, it should be possible to enhance the effects of the catecholamines by pretreating the animal or isoBated tissue with theophylline. This has been shown to be the case in a number of studies.Theophylline will enhance the inotropic effect of adrenaline on isolated atrial strips (Rall and West 1 963 ) and the phosghorylase-activating effect of adrenaline in the isolated rat heart (Mess et al. 1963). These results support the hypothesis that cyclic AMP may be involved in the effects of both the catecholamines and theophylline. A more recent study (McNeill et al. 1969) demonstrated that potentiation by theophylline of the catecholamine--induced phosghorylase activation was not dose-related to the positive inotropic effect of theophylline and was probably better correlated with the effect of theophylline on the movement of calcium. The lite...