Down-regulation of {beta}-adrenergic receptors on mononuclear leukocytes induced by dobutamine treatment in patients with congestive heart failure

(±)-Dobutamine is a positive inotropic drug usually usedto improve ventricular function in patients with congestiveheart failure (CHF). However, it has been found that haemodynamicresponses to dobutamine become blunted during continuous treatment.In this study we determined the time-dependent changes of ß-adrenergicreceptors in CHF patients treated with dobutamine. Seven CHFpatients received a continuous intravenous infusion of dobutamine(5 µg.kg^–1. min^–1) for 96 h. Blood sampleswere obtained before and every 24 h after starting the therapy.The density of ß-adrenergic receptors on mononuclearleukocytes and the plasma concentrations of norepinephrine andepinephrine were determined. During dobutamine treatment thereceptor density (fmol.mg^–1, mean±SEM) graduallydecreased from 42.8±4.4 (baseline) to 31.4±3.3(P<0.05), 25.2±4.0 (P<0.01), 18.8±5.5 (P<0.01)and 13.4±3.4 (P<0.01) at 24, 48, 72 and 96 h, respectively.However, the plasma concentrations of norepinephrine and epinephrinewere not significantly changed during the 96 h period of treatment.Thus, the ß-adrenergic receptors down-regulated asearly as 24 h after the dobutamine treatment was begun in CHFpatients. This receptor down-regulation was not associated withchanges of plasma catechol-amine concentrations, but was relatedrather to the development of drug tolerance to dobutamine.     

Glomerulonephropathy in ankylosing spondylitis

Aim: Renal abnormalities have been reported in ankylosing spondylitis (AS). The purpose of this study was to elucidate the nature of glomerulonephropathy in AS. Methods: Two hundred and sixty‐six patients with definite AS diagnosed at Taipei Veterans General Hospital, Taiwan, were enrolled. Urinary analysis and renal biopsy were performed in this study. The nature of glomerulonephropathy in AS was analyzed. Results: Twelve out of 266 (4.5%) patients had AS‐associated nephropathy manifesting as haematuria alone (11 patients) or haematuria and proteinuria (1 patient). Renal biopsy in seven patients showed IgA nephropathy in two cases, mesangial nephropathy with isolated C3 deposits in three cases, and IgM nephropathy in two cases, one of which had accompanied infectious endocarditis. Conclusion: AS‐associated nephropathy is not uncommon and mesangial nephropathy is the most common form. Microscopic haematuria and proteinuria are the most common manifestations of renal involvement.     

Programmed Death-1 Gene Polymorphisms in Patients With Systemic Lupus Erythematosus in Taiwan

To investigate the role of programmed cell death-1 (PD-1) gene polymorphisms in the development of systemic lupus erythematosus (SLE) in Taiwan, 109 patients with SLE and 100 healthy controls were enrolled in this study. The PD-1 gene polymorphisms were determined by the method of polymerase chain reaction/restriction fragment length polymorphism. This study showed that the genotype distributions of PD-1 7209 C/T polymorphisms were significantly different between the patients with SLE and controls (P=0.002, Pc=0.018). The frequencies of the PD-1 7209 C/C genotype and PD-1 7209 C allele were significantly higher in the patients with SLE than those of the controls (P=0.001, OR=2.6, 95% CI=1.5–4.6, and P=0.002, OR=2.1, 95% CI=1.3–3.4, Pc=0.018, respectively). Moreover, the association of PD-1 7209 C with susceptibility to SLE was independent of the PD-1 ligand. This study also showed that the PD-1-536 A 7146 G 7209 C 7499 G haplotype was associated with the development of SLE in Taiwan.Both Authors Contributed equally to this work     

嗜肺军团菌毒力岛基因聚合酶链反应分型鉴定

目的建立嗜肺军团菌毒力岛基因分型鉴定方法，探讨其致病特性和分布状况。方法根据GenBank公布的嗜肺军团菌核苷酸序列设计和合成嗜肺军团菌种和毒力岛基因鉴定引物，采用PCR法对25株军团菌属标准参考株，3株国内和20株广东分离嗜肺军团菌，53份临床标本和57份水样、进行嗜肺军团菌种和毒力岛基因分型鉴定。结果5株嗜肺军团菌标准株只有嗜肺军团菌1型（Philadelphia-1 ATCC 33152）12个毒力岛基因全阳性，其他4株只检出11个毒力岛基因。20株军团菌属中其他菌株，分别检出2—11个毒力岛基因；3株国内嗜肺军团菌检出11个毒力岛基因；广东地区分离的20株嗜肺军团菌，7株检出12个毒力岛基因，12株检出11个毒力岛基因，1株未检到毒力岛基因。53例病源不明性肺炎患者支气管洗液和痰液，PCR检测嗜肺军团菌DNA阳性5例（9．4％）。结论广东地区嗜肺军团菌广泛存在水源环境中，而且是医院感染性肺炎的重要病源之一。不同血清型嗜肺军团菌所含毒力岛基因不同，毒力岛基因与致病性相关。     

Mechanisms of Transition Between Double Paroxysmal Supraventricular Tachycardias

INTRODUCTION: Coexistence of double tachycardias in one patient has been infrequently reported. Furthermore, the mechanisms of transition between double paroxysmal supraventricular tachycardias have not been well studied. METHODS AND RESULTS: Thirty-five patients with two paroxysmal supraventricular tachycardias were studied. Group IA consisted of 3 patients with spontaneous transition between AV reciprocating tachycardia (AVRT) and AV nodal reentrant tachycardia (AVNRT). Group IB consisted of 13 patients without spontaneous transition between AVRT and AVNRT. Group IIA consisted of 5 patients with spontaneous transition between AVNRT and atrial tachycardia (AT). Group IIB consisted of 14 patients without spontaneous transition between AVNRT and AT. The absolute values of differences between the two tachycardia cycle lengths were significantly smaller in patients with than in those without transition between the two tachycardias (25+/-8 msec vs 90+/-46 msec, P < 0.05, IA vs IB; 21+/-25 msec vs 99+/-57 msec, P < 0.01, IIA vs IIB). The cutoff point of 25 msec had 80% positive predictive value for transition between the two tachycardias. Transition between two tachycardias occurred due to a spontaneous premature atrial complex (30%), conduction block at one limb of tachycardia (20%), or tachycardia-induced tachycardia (50%). Absence of transition between two tachycardias might be explained by the absence of a spontaneous premature atrial complex, longer cycle length of the first tachycardia, larger difference between two tachycardia cycle lengths, or induction of each tachycardia under different situations. CONCLUSION: Double supraventricular tachycardias with similar tachycardia cycle lengths are vulnerable to transition between different tachycardias.     

血液透析患者血管通路感染

目的:探讨血液透析患者血管通路感染,了解其发生率和影响因素,为制订防治对策、降低感染的发生提供参考。方法:回顾性分析379例维持性血液透析患者的血管通路感染的情况。结果:自体动静脉内瘘者312例次,1例局部感染,移植血管瘘3例次,未见感染。长期导管感染率为0.836/1000导管日,颈静脉临时管感染率为1.759/1000导管日,而股静脉临时管感染率则为4.929/1000导管日。金黄色葡萄球菌(29.8%)是最常见致病菌,其次为白葡萄球菌(24.6%)、洋葱假单胞菌(10.1%)及大肠杆菌(5.3%)。结论:内瘘感染少见,而导管相关性感染具有特异性,洋葱假单胞菌可能易致隧道感染,拔除导管是治疗的主要措施,但应注意个体化防治。     

Characteristics of Complex Fractionated Electrograms in Nonpulmonary Vein Ectopy Initiating Atrial Fibrillation/Atrial Tachycardia

Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non‐PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non‐PV ectopy initiating AF/AT. Methods: Twenty‐three patients (age 53 ± 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non‐PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real‐time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8‐second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds. Results: All patients (100%) with non‐PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non‐PV atrial ectopy or other atrial CFAEs (54.1 ± 5.6, 58.3 ± 11.3, 52.8 ± 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non‐PV ectopy in all patients (100%). During a follow‐up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non‐PV ectopy during the follow‐up. Conclusion: The sites of the origin of the non‐PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non‐PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated.