The effect of atropine on ventriculoatrial conduction during ventricular pacing in patients with and without Wolff-Parkinson-White syndrome

Electrophysiological studies were performed in five patients, two with the three without Wolff-Parkinson-White (WPW) syndrome. In the former patients group, the paroxysmal supraventricular tachycardia (PSVT) was concluded to reflect the circus movement utilizing the normal atrioventricular (A-V) conduction system for antegrade conduction and the Kent bundle for the retrograde conduction. Ventriculoatrial conduction time (VACT) was measured during ventricular pacing before and after the administration of atropine sulfate. In patients without WPW syndrome, the VACT prolonged and subsequently second degree ventriculoatrial block developed when the pacing rate was increased progressively and atropine facilitated the retrograde conduction, suggesting the ventriculoatrial conduction took place via the normal A-V pathway. In contrast, the VACT in patients with WPW syndrome remained unchanged during ventricular pacing at rates of 145/min and more before and after atropine, indicating the retrograde conduction was taking place through the Kent bundle. It is discussed that the analysis of the VACT before and after atropine serves as an aid to differentiate the underlying mechanisms of PSVT in patients with WPW syndrome.

Formation and function of Vibrio parahaemolyticus lateral flagella

Formation of the lateral flagella (L-flagella) of Vibrio parahaemolyticus was studied immunologically, using specific antiserum against L-flagella. On solid medium, L-flagella were formed at both high (37 degrees C) and low (25 degrees C) temperatures, although at high temperatures they became dissociated from the cells and decomposed in the medium. L-flagella were not formed in liquid or soft-agar medium. Formation of L-flagella was decreased by lowering the pH of the medium and repressed by transferring the cells from solid medium to liquid medium. Mutants possessing L-flagella but not a polar monotrichous flagellum (M-flagellum) swarmed on solid medium, whereas mutants were grown on solid medium and then transfered to liquid medium, the cells oscillated until they lost L-flagella. It is postulated that L-flagella are locomotive organelles on solid medium and in some cases also in liquid medium, whereas M-flagella are locomotive organelles only in liquid medium.

Antigenic difference between polar montrichous and peritrichous flagella of Vibrio parahaemolyticus

Polar monotrichous and peritrichous flagella of Vibrio parahaemolyticus were isolated and purified separately. On hydroxylapatite column chromatography, the flagellins of polar monotrichous flagella were eluted with a higher concentration of phosphate than those of peritrichous flagella. Gel diffusion tests showed an antigenic difference between the flagellins of polar monotrichous and peritrichous flagella. Electron microscope observations on cells stained with ferritin-conjugated antibodies demonstrated that polar monotrichous and peritrichous flagella reacted specifically with antimonotrichous flagellin and antiperitrichous flagellin antisera, respectively.