Clinical Experience with Orthocor II Antitachycardia Pacing System for Recurrent Tachyarrhythmia Termination

Between June 1986 and December 1988, eight patients were treated with an Orthocor II 284 A antitachycardia pacemaker (Cordis Corp., Miami, FL, USA) forsupraventricular tachycardia (SVT) and ventricular tachycardia (VT) termination. Four patients had intra-AV nodal reentrant tachycardias; 1 patient had AV reentrant tachycardia with an atrio-nodal accessory bypass tract; 2 patients had AV reentrant tachycardias with concealed Kent bundle, and 1 patient had ventricular tachycardia. All patients had been treated with three or more drugs and were considered to be drug refractory. The programmed antitachycardia mechanism used for patients with SVT were: automatic overdrive in five patients and burst scanning in two patients. In the patient with VT, a critically timed double extrastimulus with fixed coupling interval was programmed. Follow-up ranged from 2 to 30 months. The pacemaker proved to be effective in terminating tachycardias in all cases with SVT; in the patient with VT, the programmed antitachycardia mechanism was effective for a long time, but after an episode of sustained VT not interrupted by the pacemaker, the patient underwent automatic cardioverter/defibrillator (AICD) implantation. Additional antiarrhythmic therapy was required in 3 patients to control their maximum sinus rate, in 1 patient to reduce tachycardia episodes and to enable termination, and in 2 patients to prevent spontaneous atrial fibrillation. It is concluded that Orthocor II is a flexible and versatile antitachycardia pacemaker providing a safe and effective control of recurrent tachycardia in selected patients.     

Reperfusion Adjunctive Therapy: Platelet Active Agents

Changes in a coronary artery thrombus resulting from platelet activation may affect the speed of thrombolysis and the frequency of reocdusion after thrombolytic therapy. In studies performed in canine models, we have found that selected thromboxane and serotonin receptor antagonists given in combination markedly enhance the thrombolytic effect of tissue plasminogen activator, probably by preventing further platelet activation and their incorporation into a thrombus during thrombolytic therapy. The combination of a thromboxane and serotonin receptor antagonist given with heparin and tissue plasminogen activator is effective in delaying or preventing reocdusion after discontinuation of tissue plasminogen activation in experimental canine models in whom coronary artery thrombosis has been induced by an indwelling copper coil.     

Side reactions in solid phase synthesis of histidine-containing peptides

The flow-polyamide synthesis of a histidine-containing sequence (Ac-YDNVLDHLTGR) produced two major impurities which were isolated through Sample Displacement Chromatography and characterized by Fast Atom Bombardment-mass analysis. The impurities correspond to the sequence Ac-YDNVLDH, and to a peptide with the Asp residue cyclized to a succinimide. The latter side-reaction took place during the acetylation procedure, and demands attention where capping procedures are planned in the synthesis of Asp-His sequences.     

Modification of the Dissolution Behaviour of a Water-insoluble Drug,Naftazone, for Zero-order Release Matrix Preparation*

Abstract— The preparation of hydrophilic matrix tablets able to release naftazone, a water-insoluble drug, into an aqueous medium at a constant rate (zero-order dissolution) is described. Enhancement of dissolution rate of the drug was achieved using cross-linked carmellose sodium, β-cyclodextrin or hydroxypropyl-β-cyclodextrin. Hypromellose was used as a water-gelling polymer. Tablets could be prepared that released naftazone at a constant rate over 16 h.     

IMMUNOHISTOCHEMICAL STUDY ON THE PATTERN OF 50 KD CYTOKERATIN IN PSORIASIS

Three biopsies of normal skin and 15 biopsies collected from patients with psoriasis vulgaris were analyzed for the expression of the 50 kd cytokeratin using direct immunofluorescence and ABC technique before and after local treatment with anthralin 0.1% in a petrolatum base, with 0.05% betamethasone dipropionate cream, and finally, after PUVA treatment. Antiserum against the 50 kd anti-cytokeratin reacted with tissue sections of normal skin, staining cells in the basal layer, while the psoriatic skin sections before the various treatments showed a staining concerning the whole thickness of the epidermis. After the various therapies, the 50 kd cytokeratin immunoreactivity was observed only in the basal layer of those psoriatic skin sections that showed complete clinical clearing, while it was observed in the whole thickness of psoriatic patches that did not clear. These data suggest that the normalization of the 50 kd cytokeratin expression pattern can be considered as a marker of clinical remission of psoriasis.