Effects of Pharmacological Autonomic Blockade on Dual Atrioventricular Nodal Pathways Physiology in Patients with Slow-Fast Atrioventricular Nodal Reentrant Tachycardia

The purpose of this study was to investigate the atrioventricular AV nodal physiology and the inducibility of AV nodal reentrant tachycardia (AVNRT) under pharmacological autonomic blockade (AB). Seventeen consecutive patients (6 men and 11 women, mean age 39 ± 17 years) with clinical recurrent slow-fast AVNRT received electrophysiological study before and after pharmacological AB with atropine (0.04 mg/kg) and propranolol (0.2 mg/kg). In baseline, all 17 patients could be induced with AVNRT, 5 were isoproterenol-dependent. After pharmacological AB, 12 (71 %) of 17 patients still demonstrated AV nodal duality. AVNRT became noninducible in 7 of 12 nonisoproterenol dependent patients and remained noninducible in all 5 isoproterenol dependent patients. The sinus cycle length (801 ± 105 ms vs 630 ± 80 ms, P < 0.005) and AV blocking cycle length (365 ± 64 ms vs 338 ± 61 ms, P < 0.005) became shorter after AB. The antegrade effective refractory period and functional refractory period of the fast pathway (369 ± 67 ms vs 305 ± 73 ms, P < 0.005; 408 ± 56 ms vs 350 ± 62 ms, P < 0.005) and the slow pathway (271 ± 30 ms vs 258 ± 27 ms, P < 0.01; 344 ± 60 ms vs 295 ± 50 ms, P < 0.005) likewise became significantly shortened. However, the ventriculoatrial blocking cycle length (349 ± 94 ms vs 326 ± 89 ms, NS) and effective refractory period of retrograde fast pathway (228 ± 38 ms vs 240 ± 80 ms, NS) remained unchanged after autonomic blockade. Pharmacological AB unveiling the intrinsic AV nodal physiology could result in the masking of AV nodal duality and the decreased inducibility of clinical AVNRT.     

湿法活性炭(胶状活性炭)的制法及吸附性能的研究

从前在工业上所用的脱色炭,一般多以骨炭或其他的动物炭(如血炭,角蹄炭等)为主,很少使用植物炭,因为当时尚不知植物炭经活化后能变为优良的脱色炭。第一次世界大战爆发后,各国因制造防毒面具,需要大量的对气体有优良吸附性的活性炭,经研究结果,发现植物炭用适当方法处理后,除对各种毒气有优良的吸附作用外,它的脱色作用亦相当良好。随后又经不断的研究及改进,植物炭在工业上的重要性于是日渐增加。     

中国萝芙木的药理研究,Ⅲ.广东、广西和云南所产萝芙木根生物硷的降压作用和毒性的比较

我国各地所产蘿芙木绝大部分同为一种,即Rauwolfia verticillata (Lour.)Baill。赵承嘏首先从广东产蘿芙木根提出“蘿芙甲素”。林吉强等研究了它对麻醉动物的降压作用。我们首先研究了广东产蘿芙木叶的粗制剂及生物硷的降压作用,证明口服前者后可使高血压狗的血压显著下降;高血压鼠口服叶硷后,血压也明显下降。继而证明海南岛所产蘿芙木叶和根的生物硷均能显著地降低高血压动物的血压。这两种从不同植物     

Evidence of neuroanatomical connection between the superior cervical ganglion and hypoglossal nerve in the hamster as revealed by tract-tracing and degeneration methods

Previous studies have shown the existence of a sympathetic component in some cranial nerves including the hypoglossal nerve. In this study, the horseradish peroxidase (HRP) tract-tracing retrograde technique and experimental degeneration method were used to elucidate the possible neuroanatomical relationship between the superior cervical ganglion (SCG) and the hypoglossal nerve of hamsters. About 10% of the SCG principal neurons were HRP positive following the tracer application to the trunk of hypoglossal nerve. Most of the HRP-labelled neurons were multipolar and were randomly distributed in the ganglion. When HRP was injected into the medial branch of the hypoglossal nerve, some of the SCG neurons were labelled, but they were not detected when HRP was injected into the lateral branch. The present findings suggest that postganglionic sympathetic fibres from the SCG may travel along the hypoglossal nerve trunk via its medial branch to terminate in visceral targets such as the intralingual glands. By electron microscopy, the HRP reaction product was localised in the neuronal somata and numerous unmyelinated fibres in the SCG. In addition, HRP-labelled axon profiles considered to be the collateral branches of the principal neurons contained numerous clear round and a few dense core vesicles. Besides the above, some HRP-labelled small myelinated fibres, considered to be visceral afferents, were also present. Results of experimental degeneration following the severance of the hypoglossal nerve showed the presence of degenerating neuronal elements both in the hypoglossal nucleus and the SCG. This confirms that the hypoglossal nerve contains sympathetic component from the SCG which may be involved in regulation of the autonomic function of the tongue.     

Characteristic abnormal findings of ambulatory blood pressure indicative of hypertensive target organ complications

To study the correlation between ambulatory blood pressure andtarget organ complications of hypertension, ambulatory bloodpressure monitoring was performed on 290 patients with mildto moderate essential hypertension before treatment. Their targetorgan complications of hypertension were assessed by ECG, chestX-ray, urinalysis and an eye-fundus examination. An average ambulatory diastolic blood pressure value greaterthan the casual diastolic blood pressure was found in 35% ofsubjects with ECG evidence of left ventricular hypertrophy (LVH)and 5. 2% of subjects without (P<0.0001); in 36. 5% of patientswith chest roentgenographic evidence of LVH and 8.4% of patientswithout (P< 0.0001); in 38. 5% of patients with proteinuriaand 11% of patients without (P< 0. 0001); and in 27. 1% ofsubjects with retinopathy and 10. 7% of subjects without (P<0.01).A similar result was observed for the systolic blood pressure.A reversed circadian pattern of ambulatory diastolic blood pressurewas observed in 32. 5% of patients with ECG evidence of LVHand 12. 9% without (P< 0. 0001); in 28. 8% of patients withchest roentgenographic evidence of LVH and 16% without (P<0.05); in 26. 9% of subjects with proteinuria and 17. 4% without(P<0. 05); in 37. 5% of patients with retinopathy and 14.5% without (P<0.0001). A similar result was also demonstratedfor ambulatory systolic blood pressure. There was a close relationshipbetween the blood pressure load and hypertensive target organcomplications in terms of LVH and proteinuria, and between significantnocturnal reduction of ambulatory systolic blood pressure andLVH. The ambulatory blood pressure average also seemed to beara good relationship to LVH. In this study, 24 h ambulatory blood pressure monitoring revealeda close relationship between hypertensive target organ damage(ECG and chest roentgenographic evidence of L VH, proteinuriaand retinopathy) and the parameters of such measurements interms of blood pressure pattern (reversed circadian pattern),comparisons between casual blood pressure and ambulatory bloodpressure in addition to pressure load, and blood pressure average.     

Arrhythmogenic Effects of Quinidine on Catecholamine-Induced Delayed Afterdepolarizations in Canine Atrial Fibers

Arrhythmogenic Effects of Quinidine on Catecholamine-induced Delayed Afterdepolarizations. We studied the effects of quinidine and tetrodotoxin (TTX), two drugs that block Na⁺ channels, on delayed afterdepolarizations (DAD) caused by norepinepbrine in atrial fibers of the canine coronary sinus. At long stimulus cycle lengths of 10 seconds, quinidine increased the amplitude of the afterdepolarizations and caused triggered activity within 1–2 minutes. Simultaneously, action potential duration (APD) was lengthened but upstroke velocity was not decreased. Prolonged exposure to quinidine eventually decreased upstroke velocity but DAD amplitude remained larger than control and triggered activity was still induced more easily. The effects of quinidine to increase afterdepolarizations was partially related to its prolongation of the APD since shortening APD with repolarizing current decreased DAD amplitude. However, DAD amplitude remained larger than control indicating that quinidine caused triggering by other mechanisms as well. TTX, on the other hand, which blocks Na⁺ channels but shortens APD, decreased DAD amplitude and triggered activity. Part but not all of these effects resulted from the shortening of APD by TTX since prolongation of APD with depolarizing current only partially restored DAD amplitude. Anti-arrhythmic drugs, therefore, may have effects on DADs that partly result from changes in the APD. Quinidine may cause cardiac arrhythmias by virtue of its effects to potentiate triggered activity.     

Diagnosis and Ablation of Multiform Fascicular Tachycardia

Ablation Multiform Fascicular Tachycardia . Introduction: Fascicular tachycardia (FT) is an uncommon cause of monomorphic sustained ventricular tachycardia (VT). We describe 6 cases of FT with multiform QRS morphologies. Methods and Results : Six of 823 consecutive VT cases were retrospectively analyzed and found attributable to FT with multiform QRS patterns, with 3 cases exhibiting narrow QRS VT as well. All underwent electrophysiology study including fascicular potential mapping, entrainment pacing, and electroanatomic mapping. The first 3 cases describe similar multiform VT patterns with successful ablation in the upper mid septum. Initially, a right bundle branch block (RBBB) VT with superior axis was induced. Radiofrequency catheter ablation (RFCA) targeting the left posterior fascicle (LPF) resulted in a second VT with RBBB inferior axis. RFCA in the upper septum just apical to the LBB potential abolished VT in all cases. Cases 4 and 5 showed RBBB VT with alternating fascicular block compatible with upper septal dependent VT, resulting in bundle branch reentrant VT (BBRT) after ablation of LPF and left anterior fascicle (LAF). Finally, Cases 5 and 6 demonstrated spontaneous shift in QRS morphology during VT, implicating participation of a third fascicle. In Case 6, successful ablation was achieved over the proximal LAF, likely representing insertion of the auxiliary fascicle near the proximal LAF. Conclusions : Multiform FTs show a reentrant mechanism using multiple fascicular branches. We hypothesize that retrograde conduction over the septal fascicle produces alternate fascicular patterns as well as narrow VT forms. Ablation of the respective fascicle was successful in abolishing FT but does not preclude development of BBRT unless septal fascicle is targeted and ablated. (J Cardiovasc Electrophysiol, Vol. 24, pp. 297‐304, March 2013)     

HUMAN β-ENDORPHIN: SYNTHESIS AND BIOLOGICAL ACTIVITY OF ANALOGS WITH SUBSTITUTIONS IN POSITIONS 2, 9, 18, 27 AND 31

Four analogs of the opioid peptide human β-endorphin (β_h-EP) have been synthesized: [d -Lys⁹,Phe²⁷,Gly³¹]-β_h-EP, [d -Phe¹⁸,Phe²⁷,Gly³¹)-β_h-EP, [d -Thr²,d -Lys⁹,Phe²⁷,Gly³¹]-β_h-EP, and [d -Thr²,d -Phe¹⁸,Phe²⁷,Gly³¹]-β_h-EP. All are practically indistinguishable from β_h-EP in the guinea pig ileum assay. All show diminished analgesic potency in the mouse tail-flick assay.     

N.m.r. analyses of the histidine microenvironments in a human salivary proline-rich glycoprotein

The pK_a's of the three histidine residues in a proline-rich glycoprotein from human parotid saliva (PRG) were determined by 360 MHz proton n.m.r. spectroscopy. The addition of calcium (0.64 mm ) caused drops in the pK_a's of all three histidines by ～0.25 units. When imidazole and cyclo(l -histidine-l -proline) were used as model compounds, corresponding concentrations of calcium had no effect on their pK_a's. Also, the model compounds gave absolute pK_a values in good agreement with similar chemical species reported in the literature. Exchange lifetime data and previously reported hydrogen → deuterium exchange experiments suggest that the PRG histidine N^tH protons are not involved in hydrogen-bonds. Collectively, these data imply that changes in PRG conformation occur upon the addition of calcium.