OBJECTIVETo prepare a stable water-based magnetic fluid.

METHODSA water-based magnetic fluid was prepared by addition of polyvinylpyrrolidone (PVP) as the coating agent for the magnetic particles. After preparation of Fe3O4 by co-precipitation method, PVP was added for its coating, followed by ultrasonic agitation and purification.

RESULTSThe magnetic nanoparticles of homogeneously small size and water-based magnetic fluid were obtained, which had good dispersion in water with strong magnetism.

CONCLUSIONPVP can be used as a surfactant to stabilize the magnetic fluid.

Ferrous Compounds ; chemistry ; Magnetics ; Materials Testing ; Nanoparticles ; chemistry ; Povidone ; chemistry ; Surface Properties ; Surface-Active Agents ; chemical synthesis ; chemistry

Animals ; Asia ; epidemiology ; History, 20th Century ; Humans ; Influenza A Virus, H2N2 Subtype ; chemistry ; genetics ; isolation & purification ; Influenza, Human ; epidemiology ; history ; virology ; Mutation

Catheter Ablation ; Child ; Heart Septal Defects, Atrial ; surgery ; Humans ; Imaging, Three-Dimensional ; Male ; Tachycardia, Supraventricular ; surgery ; Tomography, X-Ray Computed

OBJECTIVETo study regulation of Ca(2+)-activated K(+) channels (KCa) of mesenteric artery smooth muscle cell (SMC) from 21 old patients with essential hypertension (EH) by endothelin-1 (ET-1) and prostagl E(1) (PGE(1)).

METHODSMesenteric artery branch from EH was digested by enzyme. Patch clamp technique was used to pull cell-attached and inside-out patches on mesenteric artery SMC from EH and the normotensive patients respectively. The signal channel open probability (Po), open dwell-time (To) and close dwell-time (Tc), open channel number per patch were recorded. After adding Ca(2+) (10(-8) approximately 10(-6) mol/L), ET-1(2 approximately 8 x 10(9) mol/L) and PGE(1) (10, 20, 40, 100, 200, 400 nmol/L) to cytoplasm respectively. The parameters above were observed again.

RESULTSCompared to that of normotensive patients, the activities of KCa channels of patients with EH was higher. After adding Ca(2+) to cytoplasm,the Po of KCa channels in normotensive patients increased significantly. But it was few changes in EH group. KCa channels has dual reaction to ET-1 in normotensive patients. We have found no statistics difference when ET-1 present on KCa channels of EH cases. Whereas PGE(1) can affect KCa channels current and channels kinetic significantly in side-out patches. The Po of KCa channels increased. The To protracted and the Tc curtailed in EH.

CONCLUSIONSThe activities of KCa channels of patients with EH increased significantly. but the sensitive to Ca(2+) decreased. ET-1 were few effect to KCa channels. The PGE(1) can activated KCa channels of patients with EH.

Aged ; Alprostadil ; pharmacology ; Cells, Cultured ; Endothelin-1 ; pharmacology ; Female ; Humans ; Hypertension ; metabolism ; physiopathology ; In Vitro Techniques ; Male ; Mesenteric Arteries ; cytology ; Middle Aged ; Muscle, Smooth ; metabolism ; physiopathology ; Patch-Clamp Techniques ; Potassium Channels, Calcium-Activated ; drug effects ; metabolism

OBJECTIVETo investigate the influence of persistent rapid atrial pacing on the levels of connexin 43 (Cx43) and type III collagen in pulmonary vein and atrium in a canine model.

METHODSSixteen mongrel dogs were divided into rapid atrial pacing (RAP) group (n = 8) and normal control group (n = 8) randomly. In the RAP group, atrial pacing was performed with a rate of 400 bpm for 10 weeks to establish atrial fibrillation model. The tissues of left superior pulmonary vein (LSPV), left atrial free wall (LAFW) and right atrial appendage (RAA) were collected from each dogs. The levels of Cx43 and type III collagen were measured in each tissue.

RESULTSTen weeks later, persistent atrial fibrillation was induced in all dogs in RAP group. The level of Cx43 in RAP group was higher than that in normal control group (LSPV: 3370.91 +/- 275.11 vs 1405.82 +/- 90.38, P < 0.05; LAFW: 2448.68 +/- 272.10 vs 1467.12 +/- 147.93, P < 0.05, RAA: 2331.96 +/- 199.61 vs 1288.27 +/- 216.22, P < 0.05). The level of Cx43 in LSPV was higher than that in LAFW and RAA in RAP group, whereas the difference between LAFW and RAA was not significant in RAP group. The quantities of type III collagen in RAP group were higher than those in normal control group (LSPV: 3301.97 +/- 309.70 vs 1404.56 +/- 178.02, P < 0.05; LAFW: 2477.86 +/- 190.43 vs 1479.20 +/- 187.17, P < 0.05; RAA: 2045.92 +/- 139.43 vs 1417.07 +/- 139.43, P < 0.05). The quantities of type III collagen in LSPV was higher than those in LAFW and RAA in RAP group.

CONCLUSIONSPersistent rapid atrial pacing could increase the levels of Cx43 and type III collagen in pulmonary vein and atrium in a canine model of atrial fibrillation. The levels of Cx43 and type III collagen in pulmonary vein were higher than those in atrium. This findings indicated that pulmonary vein may be a crucial regions in maintaining atrial fibrillation.

Animals ; Atrial Fibrillation ; metabolism ; physiopathology ; Cardiac Pacing, Artificial ; methods ; Collagen Type III ; blood ; Connexin 43 ; blood ; Disease Models, Animal ; Dogs ; Female ; Male ; Pulmonary Veins ; metabolism ; physiopathology

Background Recurrent atrial tachyarrhythmia (ATa) after circumferential pulmonary vein ablation (CPVA) includes atrial tachycardia (AT) and atrial fribrillation (AF). However, whether there are some differences in clinical course and mechanisms between the recurrent AT and the recurrent AF remained unclear. This study was conducted to investigate the incidence, mechanism, clinical course of the recurrent AT and AF in patients under CPVA.Methods One hundred and thirty consecutive patients (M/F=95/35) with highly symptomatic and multiple antiarrhythmic drugs (AADs) refractory paroxysmal (n=91) or persistent (n=39) AF were included. The ablation protocol consisted solely of two continuous circular lesions around the ipsilateral pulmonary veins (PV) guided by CARTO system. The endpoint of CPVA is PV isolation. For patients with recurrent ATa within 2 months after the initial procedure, cardioversion with direct current was attempted if the ATa lasted for more than 24 hours. A repeat ablation procedure was performed only for patients with AADs refractory recurrent ATa and at least followed up for 2 months after the initial procedure.Results Within 2 months after the initial procedure, 52 patients (40.0%) had experienced episodes of symptomatic recurrent ATa. Among them, 23 patients (44.2%) with recurred AT alone (AT group), 14 patients (26.9%) with recurred AF alone (AF group), and 15 patients (28.8%) with recurred AT and AF (AT plus AF group). The delayed cure rate (65.2%) in AT group was significant higher than that in AF group (21.4%, P<0.05) and AF plus AT group (26.7%, P<0.05). A repeat ablation was performed in 21 patients, including 6 patients with recurrent AT alone, 8 patients with recurrent AF alone, and 7 patients with recurrent AF plus AT. The mean number of PV gaps was 1.2±0.4 in AT group, which was significantly lower than that in AF group (2.6±0.7, P<0.05) and AF plus AT group (2.0±0.6, P<0.05). Delayed cure rate and number of PV gaps between AF group and AF plus AT group were comparable (P>0.05).Conclusions Present study indicates that recurrent AT and AF after CPVA have the different clinical course and different electrophysiological findings during repeat procedure as follows: ⑴After CPVA, spontaneous resolution of recurrent ATa was mainly found in patients with recurrent AT alone (about two thirds patients). ⑵The type of recurrent ATa after CPVA is associated with the number of PV gaps.

AIMTo study the expressions of scavenger receptor class B type I(SR-BI) and peroxisome proliferator-activated receptor gamma (PPARgamma) in atherosclerotic mini swine and provide a new mechanism for investigating the pathogenesis of atherosclerosis.

METHODSChinese mini swine were fed by a normal control diet or a high fat/high cholesterol diet for 12 months after common carotid artery injury induced by balloon denudation. Plasma total cholesterol(TC), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were determined by commercially enzymatic methods every two months. The sections, which were taken from liver and abdominal aorta, were stained with hematoxylin eosin. The expressions of SR-BI and PPARgamma mRNA and protein in liver and aorta tissue were detected by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot and immunohistochemistry respectively.

RESULTSAt the end of 12 months, plasma TC, HDL-C and TG in HFHC mini swine were increased. There were fatty liver and atherosclerotic plaque in mini swine live and aorta respectively. The expression of SR-BI was upregulated in HFHC mini swine liver and aorta tissue.

CONCLUSIONHFHC may induce atherosclerosis and the expression of SR-BI and PPARgamma. Upregulating SR-BI expression may inhibit atherosclerosis. Increasing SR-BI expression in liver and aorta may accelerate SR-BI-mediated reverse cholesterol transport and develop a new anti-atherogenic strategy.

Animals ; Arteriosclerosis ; pathology ; Atherosclerosis ; metabolism ; PPAR gamma ; metabolism ; Receptors, Scavenger ; metabolism ; Swine

BACKGROUNDWhen performing superior vena cava isolation, the major concerns are inadvertent ablation on sinus node and right phrenic nerve. However, little is known about the spatial relationship of electrical connections between superior vena cava and right atrium with the sinus node and phrenic nerve locations among individual patients.

METHODSWe studied 87 patients (male/female 60/27, mean age of (51 +/- 9) years) with atrial fibrillation. Before superior vena cava isolation, the sinus node site was defined by right atrium activation mapping during sinus rhythm and the right phrenic nerve site was localized via pacing manoeuvre. Superior vena cava was isolated by ablation at the electrical connection under the guidance of circular mapping catheter. The sites of sinus node, phrenic nerve and electrical connections were noted. Continuous variables were compared using Student's t test. A P value < 0.05 was considered statistically significant.

RESULTSRight atrium activation mapping revealed that the sinus node located at the anterior lateral segment of superior vena cava-right atrium junction in all patients. In 82 patients with detectable diaphragmatic stimulations, the phrenic nerve sites were predominantly at the lateral segment (70/82) with anterior lateral and anterior segments for a few patients. A total of 165 electrical connections were located among all 87 patients, and this averaged 1.8 +/- 0.6 (1-3) per patient. The anterior septum (72 patients (43.6%)), the anterior wall (40 (24.2%)), and the posterior septum (35 (35.4%)) of superior vena cava-right atrium junction were the electrical connection regular sites. Superior vena cava was isolated in all patients. Two patients developed sinus bradycardia, with 3 mild superior vena cava stenosis and 2 phrenic nerve palsy.

CONCLUSIONSThe sinus node, phrenic nerve and electrical connection sites were distributed along the superior vena cava-right atrium junctions at expected locations for most patients. The electrical connections were separated from the sinus node and phrenic nerve sites. With the activation mapping of right atrium and pacing along superior vena cava-right atrium junctions, the sinus node and phrenic nerve were localized and superior vena cava isolated in most patients.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Atrial Fibrillation ; pathology ; surgery ; Catheter Ablation ; methods ; Echocardiography ; Electrophysiology ; Female ; Heart Atria ; pathology ; surgery ; Humans ; Male ; Middle Aged ; Phrenic Nerve ; pathology ; surgery ; Prospective Studies ; Sinoatrial Node ; pathology ; surgery ; Vena Cava, Superior ; pathology ; Young Adult

BACKGROUNDDelayed cure had been observed in recurrent cases after index ablation of atrial fibrillation (AF), however, its mechanism and incidence have not been elucidated in detail. This study aims to investigate the impact of different ablation strategies on the incidence of delayed cure and its possible mechanisms after trans-catheter ablation of AF.

METHODSOne hundred and fifty-one consecutive cases with highly symptomatic, drug refractory AF were included in this study [M/F = 109/42, mean age (56.0 +/- 11.2) (18 - 79) years]. Segmental pulmonary vein ablation (SPVA) was performed in 83 patients with the guidance of circular mapping catheter (SPVA Group), circumferential PV linear ablation (CPVA) was carried out in the rest 68 cases under the guidance of 3 dimensional mapping system in conjunction with circular mapping catheter (CPVA Group). Delayed cure was defined as that early recurrence of atrial tachyarrhythmias (AF, atrial tachycardia, or atrial flutter) after ablation procedure was no longer observed during subsequent follow-up, and stable sinus rhythm was maintained > or = 2 months.

RESULTSEarly recurrence of atrial tachyarrhythmias was detected in 41 cases from SPVA group and 23 cases from CPVA group, and delayed cure occurred in 21.9% (9/41) of the cases from SPVA group and 47.8% (11/23) of the cases from CPVA group, more delayed cure in later group was observed (P < 0.05). Meanwhile, patients in SPVA group took a longer time to achieve a delayed cure [(27.0 +/- 18.0) days vs (14.0 +/- 8.1) days, P < 0.05], and presented more recurrent episodes [(3.50 +/- 1.08) times a week vs (2.42 +/- 1.11) times a week, P < 0.05]. However, recurrent episodes after index ablation were markedly decreased in cases with delayed cure from both groups (P < 0.05).

CONCLUSIONSDespite of an early recurrence of atrial tachyarrhythmias after index ablation of AF, delayed cure occurs in a significant number of patients undergoing either SPVA or CPVA. However, different ablation strategies place different impact on the delayed cure, more delayed cure is obtained with CPVA approach, and the delayed cure occurs earlier with this approach; the average recurrent episodes before delayed cure are also less frequently detected in CPVA group compared with those in SPVA group.

Adolescent ; Adult ; Aged ; Atrial Fibrillation ; surgery ; Catheter Ablation ; methods ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Time Factors

OBJECTIVETo investigate the advantages and disadvantages of unilateral pedicle screw fixation combined with contralateral translaminar facet screw fixation and interbody fusion with cages in the treatment of two-level lumbar vertebra diseases, by comparing bilateral pedicle screw fixation and interbody fusion with cages.

METHODSForty-nine patients with two-level lumbar diseases who received treatments from June 2009 to December 2011 were included in this study. Among these patients, 23 patients received unilateral pedicle screw fixation combined with contralateral translaminar facet screw fixation and interbody fusion with cages (combined fixation group) and the remaining 26 patients underwent bilateral pedicle screw fixation and interbody fusion with cages (bilateral fixation group). These patients consisted of 17 males and 32 females, ranging in age from 29 to 68 years old. Among these patients, lumbar intervertebral disc herniation accompanied by the spinal canal stenosis was found in 29 patients, degenerative lumbar disc diseases in 17 patients and lumbar degenerative spondylolisthesis (degree I) in 3 patients. The lesions occurred at L2,3 and L3,4 segments in 1 patient, at L3,4 and L4,5 segments in 30 patients, and at L4,5 segment and L5S1 segment in 18 patients. Wound length, operation time, intraoperative blood loss and postoperative wound drainage were compared between two groups. Intervertebral space height in the lesioned segment before and during surgery and at the latest follow up was also compared between two groups. Before surgery and at the latest follow-up, the Cobb angle of the coronal plane and sagittal plane of the lumbar spine, loosening or breakage of internal fixations, the dislocation of intervertebral cages, and interbody fusion were all evaluated in each group. The visual analogue scale (VAS) was used to measure lumbar incision pain. The Japanese Orthopedic Association (JOA) scoring system was used to evaluate the function before surgery and at the latest follow-up.

RESULTSNo wound infection or skin necrosis was observed after surgery in all patients. No cerebrospinal fluid leakage, nerve root injury, cauda equia injury or worsened neural function in the lower limb occurred in all patients during and after surgery. Wound length, operation time, intraoperative blood loss and postoperative wound drainage in the combined fixation group were superior to those in the bilateral fixation group. At postoperative 72 hours, the VAS score in the combined fixation group (1 to 4 points, mean 2.35±1.20) was significantly lower than that in the bilateral fixation group (2 to 5 points, mean 3.11±1.00; P<0.05). All the patients were followed up for 12 to 48 months, with a mean of 29 months. After surgery, intervertebral space height was well recovered in each patient and it was well maintained at the latest follow-up, and there was no significant difference between two groups (P>0.05). During follow-up, pedicle screw and translaminar facet screw loosening, dislocation or breakage and dislocation of intervertebral cages were all not found. At the latest follow-up, the Cobb angle of the coronal plane and sagittal plane of the lumbar spine was obviously improved and was not significantly different between two groups (P>0.05). The lumbar interbody fusion rate was 93.5% and 96.2% in the combined fixation group and bilateral fixation group, respectively, and there was no significant difference between them (P>0.05). There was a significant difference in JOA score between before surgery and at the latest follow-up in each patient (P<0.05), and at the latest follow-up, significant difference in JOA score was found between two groups (P<0.05).

CONCLUSIONCompared to bilateral pedicle screw fixation and lumbar interbody fusion with cages, unilateral pedicle screw fixation combined with contralateral translaminar facet screw fixation and lumbar interbody fusion with cages shows advantages including small skin incision, minimal invasion, ease of operation, highly reliable stability, high interbody fusion rate, rapid recovery in the treatment of two-level lumbar vertebra diseases and therefore can be preferred as a treatment method of this disease.

Adult ; Aged ; Female ; Humans ; Intervertebral Disc Degeneration ; surgery ; Lumbar Vertebrae ; surgery ; Male ; Middle Aged ; Pedicle Screws ; Spinal Fusion ; methods ; Spinal Stenosis ; surgery ; Spondylolisthesis ; surgery