Effect of Intraatrial Reentry on Initiation of Atrioventricular Reentrant Tachycardia

We studied the effect of intratrial reentry (IAE) on initiation of orthodromic reentrant tachycardia (ORT) in 150 patients with Wolff-Parkinson-White syndrome using His-bundle recording and the atrial extrastimulus technique. IAR was initiated by premature atrial stimulation in 44 patients (29%), and it was followed by ORT in 16 patients (11%). In 8 patients (5%), IAR promoted the initiation of ORT, whereas in 5 patients (3%), IAR inhibited the initiation of ORT. These findings suggest that ORT is frequently induced following IAR. IAR, which was frequently observed during electrophysiological studies, seems to play an important role in the initiation of ORT.     

电离辐射致股骨头坏死早期病理特点和机制的研究

Objective To observe the earlier pathological character and mechanism of radiation osteonecrosis in femoral head, in order to provide evidences for the earlier diagnosis and prevention of radiation osteonecrosis of femoral head. Methods Single femoral head of rats were irradiated singly with 30 Gy of 137 Cs γ-ray. The rats were executed after 2, 6 and 12 weeks, then the femurs were stained with HE and histopatholngical changes were observed by light microscope. The bone marrow mesenchymal stem cells (BMSCs) were cultured after 2 weeks and its proliferation and the colony formation were observed. The rats were endo-perfused with microfili contrast medium 12 weeks later, and the 3-dimensional structure of capillaries by Micro-CT was re-estabhshed to detect the pathological changes of capillaries after irradiation. Result The irradiated femur showed deranged cbondrocyte, decreased osteocyte, shrinking nucleus, increased empty bone lacuna and reduced bone trabocnla (P < 0.05). Micro-CT showed the discontinued small vessels and absence(6.65 %) capillaries in irradiated femur were obviously less than those of the unirradiated (12.3 %)(P < 0.001). The proliferation of BMSCs was slowed, the number of colony in irradiated group (10 %) was less than that of control (21 %) (P < 0.001). Conclusions The preliminary histopathological changes of osteoradionecrosis on femoral head could be increased the empty bone lacuna, and the bone lacuna above 30 % was the sign of the earlier period of osteoradionecrosis. The osteonecrosis of femoral head induced by radiation is not only correlated to the damages to the bone, but also to the damages to BMSCs and capillaries.     

Chronic Treatment with Prazosin Causes a Subtype-specific Increase in the α1-Adrenoceptor Density of the Stressed Rat Cerebral Cortex

The effects of chronic treatment with prazosin and of immobilization stress on the α₁-adrenoceptor subtypes in rat cerebral cortex have been examined. Prazosin-treated rats were allowed free access to tap water containing two different concentrations of prazosin (16 or 156 mg L^?) for 5 weeks. The mean plasma concentrations of prazosin were 5 ng mL^? in groups treated with a low dose and 8 or 14 ng mL^? in those treated with a high dose. Immobilization stress (2 h day^?, 2 weeks) or chronic treatment with a low dose of prazosin caused no significant change in the affinity for [³H]prazosin or in the maximum number of α₁-adrenoceptor sites (B_max). However, treatment with prazosin (low dose) combined with stress increased the density of α₁-adrenoceptors with low affinity for prazosin. Treatment with a high dose of prazosin increased the density of α_1L-adrenoceptors, irrespective of stress loading. The densities of α_1A- and α_1B-adrenoceptors with high affinity for prazosin were increased only after treatment with a high dose of prazosin in combination with stress. These results indicate that three distinct α₁-adrenoceptor subtypes, α_1A, α_1B and α_1L, might be affected differently by treatment with prazosin and by stress.     

Role of ureteroscopic biopsy in the management of upper urinary tract malignancy

BACKGROUND: The aim of the study presented here was to examine the accuracy of ureteroscopic biopsy in the diagnosis of upper urinary tract transitional cell carcinoma (TCC) and whether nephron-sparing management (holmium YAG laser, transurethral resection or partial ureterectomy) is possible or not based on pathological diagnosis. METHODS: Forty consecutive patients underwent ureteroscopic biopsy with the use of 3-Fr cold cup forceps. Pathological diagnosis of the biopsy sample and grade or stage of surgically resected tumors were compared. In patients with grade 1 or 2 TCC diagnosed by ureteroscopic biopsy, the disease-free and survival rates determined whether nephron-sparing management was performed or not. RESULTS: There were no major complications associated with ureteroscopic biopsy. The pathological grading of the biopsy specimen was almost the same as that of the surgically resected specimen. Eighty five percent of grade 2 or 3 TCC showed muscle invasive disease. There were no significant differences in the disease-free and survival rates between the nephroureterectomy and the nephron-sparing management groups, except for grade 3 or pT3 tumors. CONCLUSION: Ureteroscopic biopsy is safe and accurate if sufficient tissue sample is obtained. Ureteroscopic biopsy should be performed in patients who require nephron-sparing management. Nephroureterectomy can be avoided if the tumor is confirmed as low-grade.     

Echographic Detection of Latent Severe Thrombotic Stenosis of the Superior Vena Cava and Innominate Vein in Patients with a Pacemaker: Integrated Diagnosis Using Sonography, Pulse Doppler, and Color Flow

Thrombosis of the innominate vein and SVC is a serious complication in patients with pacemakers, inducing puhnonary embolism or SVC syndrome. Venography is the definitive method for its diagnosis; however, it is too invasive for related studies. The purpose of this study was to validate sonography, pulse Doppler, and color flow in detecting noninvasively innominate vein or SVC thrombosis in patients with pacemakers. In 53 patients with pacemakers, the 1 severe SVC stenosis and 18 severe innominate vein stenoses due to thrombosis were diagnosed by digital subtraction angiography. Sonography accurately showed the severe SVC stenosis due to thrombosis, but had limitations on the innominate vein thrombosis. Color flow demonstrated mosaic flow, indicating poststenotic turbulence due to stenosis of the innominate vein and SVC caused by thrombosis in 15 of 16 patients, and pulse Doppler disclosed absence of flow due to complete occlusion of the innominate vein in 2 of 2 patients. Sensitivity and specificity for detecting severe innominate vein stenosis due to thrombosis using combined color flow and pulse Doppler was 94% and 100%, respectively. In conclusion, sonography, pulse Doppler, and color flow allow accurate detection of severe innominate vein or SVC stenosis due to thrombosis, and are therefore useful for the follow-up of patients with a pacemaker.     

国产几种茄属植物中水解羟基茄碱soIasodine的分离

由喀西茄(Solanum khasianum C.B.Clarke)浆果中分离出的甾体生物碱,证明为水解羟基茄碱。同时,还报告了两种茄属植物浆果中水解羟基茄碱的含量。     

Genetic Polymorphism of KCNH2 Confers Predisposition of Acquired Atrial Fibrillation in Chinese

Introduction: Nonfamiliar atrial fibrillation (AF) is usually associated with acquired structural heart disease, including valvular heart disease, coronary artery disease, and hypertension. Suggestive evidence indicates that these forms of acquired AF are more likely to occur in individuals with a genetic predisposition. We investigated the effect of the potassium channel voltage-gated subfamily member 2 ( KCNH2 ) gene on the prevalence of acquired AF in a Chinese population.
Methods: In a pair-matched, hospital-based case control study (297 vs 297) conducted in Chinese Hans, we investigated 4 tagging single nucleotide polymorphisms (tSNPs), rs1805120, rs1036145, rs3807375, and rs2968857 in the KCNH2 gene, and determined their association with AF acquired from structural heart diseases.
Results: We did not observe the association of rs1036145, rs3807375, and rs2968857 with AF. However, we determined that the tSNP, rs1805120, in exon 6 confers the risk of AF in Chinese Hans. Both genotype and allele frequencies of rs1805120 were distributed differently in cases and controls (P = 0.0289 and P = 0.0172, respectively). The most significant association was observed under a recessive model for the minor GG genotype with a 1.45-fold risk of developing AF (95% confidence interval 1.09–1.93, P = 0.012). The significance remained after controlling for the covariates of age, smoking, BMI, hypertension, and diabetes.
Conclusion: We report a new genetic variation (rs1805120) in the KCNH2 gene that predisposes Chinese Han individuals to the risk of acquired AF. Further genetic and functional studies are required to identify the etiological variants in linkage disequilibrium with this polymorphism.     

Impaired Coronary Microvascular Dilation Correlates with Enhanced Vascular Smooth Muscle MLC Phosphorylation in Diabetes1

Objective: Impaired endothelium‐independent vasodilation is a known consequence of types 1 and 2 diabetes, and the mechanism of impaired vasodilation is not well understood. The following study investigated the effects of types 1 and 2 diabetes in endothelial‐independent vasodilation associated with coronary vascular smooth muscle (VSM) relaxation and contractile signaling mechanisms. Materials and Methods: Type 1 diabetes was induced in Yucatan miniswine via alloxan injection and treated with or without insulin (DM and IDM). Nondiabetic swine served as controls (ND). Expression and/or phosphorylation of determinants of VSM relaxation and contraction signaling were examined in coronary arteries and microvessels. Coronary microvessel relaxation was assessed by using sodium nitroprusside (SNP). In addition, SNP‐induced vasodilation and myosin light‐chain (MLC) phosphorylation was determined in coronary microvessels isolated from ND and type 2 diabetic human atrial appendage. Results: Diabetic impairment in SNP‐induced relaxation was completely normalized by insulin. Soluble guanylate cyclase (sGC) VSM expression decreased in both DM and IDM groups and did not correlate with vasorelaxation. Phosphorylation of MLC and myosin phosphatase increased in the DM group and MLC phosphorylation strongly correlated with impaired VSM relaxation (r=0.670, P<0.01). Coronary microvessels from type 2 diabetic human patients exhibited similarly impaired vasodilation and enhanced VSM MLC phosphorylation. Conclusions: Impaired vasodilation in type 1 diabetes correlates with enhanced VSM MLC phosphorylation. In addition, enhanced VSM MLC phosphorylation is associated with impaired vasodilation in type 2 diabetes in humans.     

类鼻疽骨、关节及骨髓感染的临床特点

目的 分析类鼻疽骨、关节及骨髓感染的临床特征,为类鼻疽骨、关节及骨髓感染的诊治提供参考,减少漏诊和误诊,提高患者预后.方法 回顾性分析21例类鼻疽骨、关节及骨髓感染患者的流行病学和临床特点;采用Etest法检测致病菌对抗菌药物的敏感性.结果 21例患者中男19人,女2人,年龄范围35～80岁,8人职业为农民,11人在台...     

New flavonoids and other constituents from Lespedeza cuneata

Two new flavonoids, 6,8,3′,4′-tetrahydroxy-2′-methoxy-7-methylisoflavanone (1) and 6,8,3′,4′-tetrahydroxy-2′-methoxy-6′-(1,1-dimethylallyl)-isoflavone (2), were isolated from the 95% ethanolic extract of the dried roots of Lespedeza cuneata together with betulinic acid (3), β-sitosterol (4), hexacosanoic acid 2,3-dihydroxy-propyl ester (5), which were isolated from this plant for the first time. Their structures were elucidated by spectral analysis.