Trimethaphan is a direct arterial vasodilator and an alpha-adrenoceptor antagonist

In helically cut strips of dog cerebral, mesenteric, and femoral arteries contracted with prostaglandin(PG)F2 alpha, trimethaphan (10(-5)-10(-3)M) caused a dose-related relaxation that was not influenced by atropine, propranolol, diphenhydramine, cimetidine, aminophylline, or indomethacin. Trimethaphan-induced relaxation was greater in extracerebral than in cerebral arteries. The relaxation was greater in phenylephrine-contracted arteries than in PGF2 alpha-contracted arteries. On the other hand, hexamethonium did not relax the arteries. Trimethaphan (10(-4)-10(-3)M) shifted the dose-response curve for norepinephrine in mesenteric arteries to the right, but failed to influence the contractile response to 25 mM KCl. Treatment with trimethaphan (10(-4)-10(-3)M) protected alpha-adrenergic receptors from persistent blockade by phenoxybenzamine. Trimethaphan (10(-7)-3 X 10(-6)M) and hexamethonium (3 X 10(-8)-10(-6)M) significantly attenuated the contractile response of mesenteric arteries to nicotine in a dose-dependent manner, but did not alter the response to transmural electrical stimulation. The antinicotinic potency of trimethaphan was approximately one-fourth that of hexamethonium. It is concluded that, unlike hexamethonium, trimethaphan acts directly on vascular smooth muscle to induce vasodilation, more prominently in extracerebral arteries than in cerebral arteries. In high concentrations, trimethaphan appears to possess an alpha-adrenergic blocking action.     

Aliphatic polyamides containing tricyclic fused rings

A series of polyamides containing thianthrene, phenoxathiin, and dibenzo-p-dioxin units were synthesized from the corresponding tricyclic fused ring diamines and aliphatic diacid chlorides by solution polycondensation at low temperature. These polyamides showed improved thermal stability, while maintaining the good solubility of aliphatic polyamides. The thermal stability of the series of polyamides increased in the order of the thianthrene containing polymers < phenoxathiin containing polymers < dibenzo-p-dioxin containing polymers. Glass transition temperatures of these polymers were estimated by thermomechanical analysis as well as by temperature-resistivity curves. Polyamides derived from 2,8-oriented tricyclic diamines showed somewhat lower glass transition temperatures than those from 2,7-oriented diamines.     

Ultrastructural sites of blister formation in dermatitis herpetiformis: report of a case and retrospective electron microscopy using routine histologic preparations

Electron microscopy of the skin lesions of a patient with the classical type of dermatitis herpetiformis (DH), showing granular IgA deposits beneath the epidermis and gluten-sensitive enteropathy, revealed that the initial changes of the vesicular or blister formation are neutrophilic invasion above the basal lamina and consequent degeneration of the basal cells. Retrospective electron microscopic studies using the refixation-reembedding method performed on four previous cases of classical DH revealed the coexistence of degeneration of the basal cells and dermal vacuolization in two cases, blister formation above the basal lamina in one case, and blister formation in the uppermost dermis with basal lamina remaining along the blister roof in one case. The infiltrating inflammatory cells in the skin of classical type of DH seem to injure the epidermal-dermal junction, including the basal cells and the uppermost dermis, to initiate the blister or vesicular formation.     

Serotonin antagonism in isolated canine cerebral arteries.

In helically-cut strips of canine cerebral arteries, the dose-response curve of serotonin was not influenced by 10(-7) M phentolamine but was slightly moved to the right and downward at 10(-6) M. The contractile response to serotonin was unaffected by cocaine (3 X 10(-6)M), atropine (10(-6) M) and propranolol (10(-6) M). The addition of lysergic acid diethylamide (LSD), ergotamine and methysergide caused a dose-dependent contraction. Treatment with LSD (10(-9) and 10(-8) M), ergotamine (10(-10) to 10(-8) M) and methysergide (10(-8) to 10(-6) M) shifted the dose-response curve of serotonin to the right and downward in a dose-dependent manner. The inhibitory effect of methysergide was reversed by washing, while that of ergotamine was not reversed. Apparent pA2 values of LSD, ergotamine and methysergide were 9.17, 9.63 and 7.92, respectively. Contractile responses to 20 mM K+ were not significantly influenced by these blocking agents even in the highest concentrations used. It may be concluded that an alpha-adrenergic mechanism is not involved in the genesis of serotonin-induced contractions and that serotonin acts directly on serotonergic receptors in canine cerebral arteries.