Effects of low-density lipoprotein cholesterol on sleep apnea: Insights from a rat model of cardiovascular autonomic dysregulation

INTRODUCTION

The levels of low-density lipoprotein (LDL) cholesterol in plasma are important risk factors for coronary heart disease. Several reports suggest that elevated plasma cholesterol is associated with cardiac arrhythmias. In a subsequent study investigating LDL cholesterol levels and the frequency of LDL cholesterol measurements, a positive correlation was observed between the severity of sleep apnea and visit-to-visit LDL cholesterol variability. Our objective was to assess the effects of hypercholesterolemia on cardiac autonomic activity, disordered sleep patterns, and increased incidence of arrhythmias in freely moving rats.

METHODS

Wireless transmission of polysomnographic recordings was performed in control and high cholesterol male rats during normal daytime sleep. Spectral analyses were conducted on the electroencephalogram and electromyogram (EMG) recordings to distinguish active waking, quiet sleep, and paradoxical sleep. Heart rate variability power spectrum analysis was used to measure cardiac autonomic activity.

RESULTS

The high cholesterol group exhibited a higher low-frequency (LF)/high-frequency (HF) power ratio during all sleep stages compared to the control group. Additionally, the frequency of sleep interruptions was increased in the high cholesterol group compared to the control group.

CONCLUSIONS

Our results show significant sleep fragmentation with sympathetic hyperactivity after exposure to high cholesterol. This indicates that high cholesterol may increase the risk of sleep apnea and poor sleep quality by disrupting autonomic homeostasis.

Renal sympathetic denervation ameliorates the activated inflammatory response through JAK-STAT pathway in a chronic obstructive sleep apnea animal model

OBJECTIVES

Obstructive sleep apnea (OSA) is known to increase the risk of cardiovascular disease and inflammation plays a significant role in this process. Renal denervation (RDN) is a novel approach aimed at reducing sympathetic nervous system activity. The role of RDN in the inflammatory response to chronic OSA (COSA) is currently unclear. The main objective was to study inflammatory mechanisms in the rabbit heart with COSA and the effects of RDN.

METHODS

Eighteen rabbits were randomized into three groups: sham control, COSA, and COSA-RDN. COSA and COSA-RDN groups received liquid silicone injections, while the sham control group received normal saline. We performed combined surgical and chemical RDN through bilateral retroperitoneal flank incisions in the COSA-RDN group after silicone injections. The inflammatory mechanisms were assessed through immunoblotting, real-time PCR, and ELISA after the experiment.

RESULTS

H&E staining showed immune cell infiltration in COSA, which decreased after RDN treatment. The level of α7nAChR was significantly reduced in COSA compared to the sham control but was restored to a similar level in the COSA-RDN group. Furthermore, the expressions of p-JAK2 and p-STAT3 were significantly reduced in COSA but showed an up-regulation following RDN treatment. Similarly, levels of the inflammatory markers IL-6, IL-1β and TNF-α were markedly increased in COSA but decreased after RDN therapy. We observed NF-κB activation in the COSA rabbit model, which decreased after RDN treatment, as evidenced by decreased NF-κB expression.

CONCLUSIONS

Our study suggests that RDN treatment may prevent COSA-associated heart inflammation via the JAK2-STAT3 signaling pathway.

Exploring the Benefits of 3D-Printed Bolus in Cone Beam CT for Modified Radical Mastectomy Breast Cancer

PURPOSE/OBJECTIVE(S)

To improve the accuracy of superficial dose coverage for patients undergoing modified radical mastectomy (MRM), boluses are frequently applied to the skin surface of targeted region during radiotherapy. The irregular curvature of MRM breast cases results in discrepancies of dosimetry and poor contact. Additionally, the presence of an air gap causes unnecessary high-dose escalation and uncertainty in dose calculation, making the use of commercial flat bolus problematic. This study evaluated the effectiveness of 3D-printed bolus by comparing it to commercial bolus in setup variations and dosimetric compliance through daily cone-beam computed tomography (CBCT) scans.

MATERIALS/METHODS

Ten patients underwent MRM were divided into 2 groups. 5 patients treated with 0.5 cm commercial bolus as group A while the other 5 patients covered by 3D Bolus as group B. 3D bolus was made of polylactic acid filament (PLA) and contoured in advance with thickness of 0.5 cm on the surface of target. Positional errors were recorded through daily image guidance and compared with the images. Both groups had right-sided breast with neck lymph nodes involved and received 50 Gy in 25 fractions using 4 partial arcs of the volumetric modulated arc therapy (VMAT) technique. The CBCTs were recalculated through treatment planning system (TPS) to assess superficial dose coverage. A two-tailed student's t-test was applied.

RESULTS

Groups A and B pitch angles were -0.203 ± 0.837° and 0.334 ± 0.909° (p = 0.0003). Roll angle were 0.313 ± 0.728° and -0.633 ± 1.286° (p = 0.0000013). Yaw angle were -0.034 ± 0.872° and 0.018 ± 0.883° (p = 0.721). There was a trend of differences in the Z-axis and significant statistical differences in the pitch and roll angles due to aligning gel layers directly with group A's body surface, while 3D bolus rigidly adherence to group B's delineated curve. In the planned target volume (PTV), the CI and HI of group A were 0.9448±0.0208 and 1.2061±0.0448, respectively, while 0.9776±0.0144 and 1.1472±0.0206 (p<0.005) were for group B. As for the superficial region, which is defined from body surface to 0.5cm inside PTV, CI and HI of A were 0.8290±0.0599 and 1.4675±0.2434, while for B, they were 0.9753±0.0214 and 1.1330±0.0126, respectively (p<0.005).

CONCLUSION

The study analyzed the results through image comparison and investigated the CI and HI between two types of boluses. The 3D bolus reduces setup errors and improves dose coverage especially when superficial region is concerned. Better consistency of patient repositioning and dosimetry can be achieved and proved by daily assessment of CBCT scan. The customization of 3D bolus with integration of TPS and CT scans provides a solution to the inadequacies of commercial bolus. The results suggest that the use of 3D bolus is a promising development in radiation therapy for MRM breast cancer patients.

Predicting Treatment Response of Esophageal Cancer Treated by Concurrent Chemoradiotherapy Using Pre- and Posttreatment 18F-FDG PET Metabolic Characteristics

PURPOSE/OBJECTIVE(S)

This study hypothesizes that metabolic characteristics of esophageal tumors can be used to predict treatment response, which considers changes in the primary tumor and lymph nodes, for patients receiving neoadjuvant concurrent chemoradiotherapy (CCRT).

MATERIALS/METHODS

This study retrospectively included 60 esophageal cancer patients receiving CCRT followed by surgery. All patients received 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) examinations prior to CCRT and in the interval between CCRT and surgery. On the pre-treatment FDG PET/CT images, the maximum standardized uptake value (SUVMaxPre) within the primary tumor was identified. By computerized methods, the CT images of pre- and post-treatment FDG PET/CT were registered. Then, the coordinates of SUVMaxPre were transformed to the post-treatment FDG PET images and delineated a sphere with a diameter of 5 cm to indicate the tumor position. After excluding air, the sphere was partitioned into several metabolic volumes by the optimal dichotomy of high and low metabolic FDG uptakes. Finally, the volume with the shortest distance to the center was adopted and represented by the maximum standardized uptakes (SUVMaxPost). Two additional features, SUVDiff and SUVDiffR, were defined as SUVMaxPost - SUVMaxPre and (SUVMaxPost - SUVMaxPre) / SUVMaxPre. Besides, for defining treatment response, the patients with and without residual tumors were defined as ypT+ and ESOCR based on the histopathology results of surgery. The ESOCR was further classified into pCR to indicate the absence of lymph node metastasis and LNM for remaining. Finally, the area under the receiver operating characteristic curve analysis (AUC) was conducted to assess the features' ability to differentiate two treatment responses. Kruskal-Wallis test was used to evaluate the differences in features between treatment responses.

RESULTS

Of the 60 patients, 55 were men (92%), and the mean age was 58. The number of tumors at the esophagus's upper, middle, and lower third were 8, 18, and 34, respectively. Ninety-eight percent of the tumors were squamous cell carcinomas (59/60). The patient numbers of ypT+ and ESOCR were 43 and 17 of which contained 13 pCR and 4 LNM. The SUVDiff and SUVDiffR exhibited a significant ability to identify the ESOCR with AUC = .337 (p = .05) and AUC = .290 (p = .012), respectively. In addition, a statistically significant difference was found among the three groups of ypT+, pCR, and LNM on SUVMaxPre (H = 6.252 and p = .044), SUVDiff (H = 7.948 and p = .019), and SUVDiffR (H = 8.405 and p = .015). In the post-hoc tests corrected by the Bonferroni, the difference between ypT+ and LNM was significant on these features.

CONCLUSION

The metabolic characteristics extracted from pre- and post-treatment FDG PET/CT images could indicate treatment response and disease progression. Further studies are warranted.

Neural mechanism facilitating PM2.5-related cardiac arrhythmias through cardiovascular autonomic and calcium dysregulation in a rat model

Particulate matter < 2.5 μm (PM2.5) exposure is associated with increased arrhythmia events and cardiovascular mortality, but the detailed mechanism remained elusive. In the current study, we aimed to investigate the autonomic alterations in a rodent model after acute exposure to PM2.5. Twelve male WKY rats were randomized to control and PM2.5 groups. All were treated with 2 exposures of oropharyngeal aerosol inhalations (1 μg PM2.5 per gram of body weight in 100 μL normal saline for the PM2.5 group) separately by 7 days. Polysomnography and electrocardiography were surgically installed 7 days before oropharyngeal inhalation and monitored for 7 days after each inhalation. Physiologic monitors were used to define active waking (AW), quiet sleep (QS), and paradoxical sleep (PS). Autonomic regulations were measured by heart rate variability (HRV). The protein expression of ventricular tissue of the 2 groups was compared at the end of the experiment. In sleep pattern analysis, QS interruption of the PM2.5 group was significantly higher than the control group (0.52 ± 0.13 events/min, 0.35 ± 0.10 events/min, p = 0.002). In HRV analysis, the LF/HF was significantly higher for the PM2.5 group than the control group (1.15 ± 0.16, 0.64± 0.30, p = 0.003), largely driven by LF/HF increase during the QS phase. Ionic channel protein expression from Western blots showed that the PM2.5 group had significantly lower L-type calcium channel and higher SERCA2 and rectifier potassium channel expressions than the control group, respectively. Our results showed that acute PM2.5 exposure leads to interruption of QS, sympathetic activation, and recruitment of compensatory calcium handling proteins. The autonomic and calcium dysregulations developed after PM 2.5 exposure may explain the risk of sleep disturbance and sleep-related arrhythmia.

Renal denervation reverses ventricular structural and functional remodeling in failing rabbit hearts

Renal denervation (RDN) suppresses the activity of the renin-angiotensin-aldosterone system and inflammatory cytokines, leading to the prevention of cardiac remodeling. Limited studies have reported the effects of renal denervation on ventricular electrophysiology. We aimed to use optical mapping to evaluate the effect of RDN on ventricular structural and electrical remodeling in a tachycardia-induced cardiomyopathy rabbit model. Eighteen rabbits were randomized into 4 groups: sham control group (n = 5), renal denervation group receiving RDN (n = 5), heart failure group receiving rapid ventricular pacing for 1 month (n = 4), and RDN-heart failure group (n = 4). Rabbit hearts were harvested for optical mapping. Different cycle lengths were paced (400, 300, 250, 200, and 150 ms), and the results were analyzed. In optical mapping, the heart failure group had a significantly slower epicardial ventricular conduction velocity than the other three groups. The RDN-heart failure, sham control, and RDN groups had similar velocities. We then analyzed the 80% action potential duration at different pacing cycle lengths, which showed a shorter action potential duration as cycle length decreased (P for trend < 0.01), which was consistent across all groups. The heart failure group had a significantly longer action potential duration than the sham control and RDN groups. Action potential duration was shorter in the RDN-heart failure group than the heart failure group (P < 0.05). Reduction of conduction velocity and prolongation of action potential duration are significant hallmarks of heart failure, and RDN reverses these remodeling processes.

AD-9308 ameliorates the impacts of 4-HNE on the progress of pulmonary arterial hypertension in aldehyde dehydrogenase 2*1*2 knock-in mice

 

Endothelial dysfunctions play a critical role on the development of pulmonary arterial hypertension (PAH). It has been reported that the one-year mortality rate is still up to 15% even with PAH-targeted therapy, implying that there may be untargeted pathways. 4-hydroxynenonal (4-HNE), an unsaturated aldehyde, is highly induced in the lungs of PAH animals and its serum levels were also reported to be higher in PAH patients. 4-HNE is metabolized by mitochondrial aldehyde dehydrogenase (ALDH2), which is dysfunctional in near 40% of East Asian people. Currently, the impacts of 4-HNE on endothelial dysfunctions in the development of PAH are unclear. In terms of translational medicine, we proposed that modulation of 4-HNE level may alleviate the progress of PAH patients with ALDH2 deficiency.

We found that 4-HNE alone was not sufficient to induce pulmonary artery endothelial cell (PAEC) functional changes, including proliferation, migration and tube formation, whereas their effects emerge from the depletion of ALDH2. We further mimicked human ALDH2 functional deficiency by using daidzin (DZN), an inhibitor which is able to block the substrate binding site of ALDH2. ALDH2 functional inhibition alone did not induce any PAEC functional change, while an add-on of 4-HNE impaired PAEC functions. In addition, 4-HNE significantly reduced eNOS activity with combined DZN treatment. Consistent with the mechanism of ALDH2 activity-mediated angiogensis, ALDH2 enhancers Alda-1 and AD-5591 completely reverse the anti-angiogenic effects of 4-HNE in the presence of DZN. To further confirm whether ALDH2 functional deficiency impact on PAH development in mammals, heterozygous ALDH2*1/*2 transgenic and wild-type mice were subjected to chronic hypoxia to induce PAH. ALDH2*1/*2 transgenic mice had similar right ventricular systolic pressure (RVSP) as wild-type mice. However, after exposure to chronic hypoxia, ALDH2*1/*2 transgenic mice indeed developed a significantly higher RVSP than that in wild-type mice. Furthermore, we demonstrated that 4-HNE expression was profoundly enhanced in ALDH2*1/*2 transgenic mice by chronic hypoxia-induced PAH with pulmonary artery smooth muscle cell hyperplasia. More importantly, we found that AD-9308, an enhancer of ALDH2 significantly decreased hypoxia-induced RVSP elevation in heterozygous ALDH2*1/*2 transgenic mice.

Taken together, our data demonstrate that 4-HNE and ALDH2 functional deficiency potentially contribute to PAH development and worsening, and that ALDH2 enhancers may be promising as a PAH adjunct therapy, particularly for patients with ALDH2 nonfunctional alleles.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Science and Technology, Taiwan

Evidence of Ventricular Arrhythmogenicity and Cardiac Sympathetic Hyperinnervation in Early Cirrhotic Cardiomyopathy

Cirrhotic cardiomyopathy (CMP) is associated with altered cardiac electrophysiological (EP) properties, which leads to the risk of ventricular arrhythmias (VAs). We aimed to evaluate the EP properties, autonomic, and structural remodeling in a rabbit model with early liver cirrhosis (LC). Twelve rabbits were assigned to the sham and LC groups. The early-stage LC was induced by the ligation of the common bile duct. All rabbits received an EP study, VA inducibility test, myocardial, and liver histology staining. Western blot analyses of protein expression and tyrosine hydroxylase stain for sympathetic nerves were performed. The effective refractory period the LC group was significantly longer than the sham group [i.e., left ventricle (LV) 205.56 ± 40.30 vs. 131.36 ± 7.94 ms; right ventricle (RV) 206.78 ± 33.07 vs. 136.79 ± 15.15 ms; left atrium (LA) 140.56 ± 28.75 vs. 67.71 ± 14.29 ms; and right atrium (RA) 133.78 ± 40.58 vs. 65.43 ± 19.49 ms, all p < 0.01], respectively. The VA inducibility was elevated in the LC group when compared with the sham group (i.e., 21.53 ± 7.71 vs. 7.76 ± 2.44%, p = 0.013). Sympathetic innervation (10²/μm²/mm²) was increased in all cardiac chambers of the LC group compared with the sham group (i.e., LV 9.11 ± 4.86 vs. 0.17 ± 0.15, p < 0.01; RV 4.36 ± 4.95 vs. 0.18 ± 0.12, p = 0.026; LA 6.79 ± 1.02 vs. 0.44 ± 0.20, p = 0.018; and RA 15.18 ± 5.12 vs. 0.10 ± 0.07, p = 0.014), respectively. Early LC is presented with an increased ventricular vulnerability, structural heterogeneity, and sympathetic innervation. Close monitoring for fatal arrhythmias is warranted in patients with early stages of LC.

Renal denervation prevents myocardial structural remodeling and arrhythmogenicity in a chronic kidney disease rabbit model

BACKGROUND

The electrophysiological (EP) effects and safety of renal artery denervation (RDN) in chronic kidney disease (CKD) are unclear.

OBJECTIVE

The purpose of this study was to investigate the arrhythmogenicity of RDN in a rabbit model of CKD.

METHODS

Eighteen New Zealand white rabbits were randomized to control (n = 6), CKD (n = 6), and CKD-RDN (n = 6) groups. A 5/6 nephrectomy was selected for the CKD model. RDN was applied in the CKD-RDN group. All rabbits underwent cardiac EP studies for evaluation. Immunohistochemistry, myocardial fibrosis, and renal catecholamine levels were evaluated.

RESULTS

The CKD group (34.8% ± 9.2%) had a significantly higher ventricular arrhythmia (VA) inducibility than the control (8.6% ± 3.8%; P <.01) and CKD-RDN (19.5% ± 6.3%; P = .01) groups. In the CKD-RDN group, ventricular fibrosis was significantly decreased compared to the CKD group (7.4% ± 2.0 % vs 10.4% ± 3.7%; P = .02). Sympathetic innervation in the CKD group was significantly increased compared to the control and CKD-RDN groups [left ventricle: 4.1 ± 1.8 vs 0.8 ± 0.5 (10² μm²/mm²), P <.01; 4.1 ± 1.8 vs 0.9± 0.6 (10² μm²/mm²), P <.01; right ventricle: 3.6 ± 1.0 vs 1.0 ± 0.4 (10² μm²/mm²), P <.01; 3.6 ± 1.0 vs 1.0 ± 0.5 (10² μm²/mm²), P <.01].

CONCLUSION

Neuromodulation by RDN demonstrated protective effects with less structural and electrical remodeling, leading to attenuated VAs. In a rabbit model of CKD, RDN plays a therapeutic role by lowering the risk of VA caused by autonomic dysfunction.

Delayed association of acute particulate matter 2.5 air pollution exposure with loss of complexity in cardiac rhythm dynamics: insight from detrended fluctuation analysis

There is a delayed (lag 1 to 2 days) correlation between acute PM 2.5 (particulate matter < 2.5 μm in aerodynamic diameter) exposure and cardiovascular events, but the underlying mechanism remained unclear. We aimed to investigate the delayed impact of acute PM 2.5 exposures on cardiac autonomics through linear and nonlinear heart rate variability (HRV) analyses. Among 6912 patients who had received 24-h Holter ECG between October 1, 2015, to October 31, 2016, 56 patients (31 males, 70.3 ± 12.7 years old) were enrolled. We classified the patients as high (> 35.4 μg/m³) or low (< 35.4 μg/m³) PM 2.5 groups according to their PM 2.5 exposures on the day of Holter recordings (day 0) lag 1 and lag 2 days. Linear and nonlinear HRV parameters〔Detrended fluctuation analysis (DFA) slopes 1 and 2〕were compared. Baseline characteristics were similar between groups. Linear and nonlinear HRV parameters were similar between high- and low-exposure groups on day 0 and lag 1 day, respectively. However, DFA slope 1 was significantly lower in the high-exposure group on lag 2 days (0.784 ± 0.201 vs. 0.964 ± 0.274, p = 0.021). DFA slope 1 of the high-exposure group was significantly lower on daytime periods (9 am to 9 pm, 8 am to 4 pm and 4 pm to 12 pm) but not on nighttime periods. High lag 2 days PM 2.5 exposure is associated with low DFA slope 1 and the relationship is diurnal. This suggests that air pollution might have a delayed impact on the cardiovascular autonomic system.

The Effect of Participation Motivations on Interpersonal Relationships and Learning Achievement of Female College Students in Sports Club: Moderating Role of Club Involvement

The aim of this study is to explore the moderating effect of club involvement on the relationships of female college students’ sport club participation motivations for interpersonal relationships and learning achievement. Using cluster sampling, a structured questionnaire was distributed to 450 female college students located in northern, central, and southern Taiwan with a valid return rate of 96.2%. Using partial least squares structural equation modeling (PLS-SEM) analysis, the study found that the female college students’ participation motivations both affected interpersonal relationships and learning achievement positively. In addition, the moderating effects of club involvement on interpersonal relationships and learning achievement were both significant. Club involvement enhanced the effects of the female college students’ sport club participation motivations for interpersonal relationships and learning achievement. According to the results and discussion, practical application and future research suggestions were provided.

Renal denervation ameliorates the risk of ventricular fibrillation in overweight and heart failure

Aims

Both obesity and heart failure (HF) are associated with sudden cardiac death. The current study aimed to investigate the effects of overweight and HF on the substrate for ventricular fibrillation (VF), and whether renal denervation (RDN) can protect the heart from sympathetic activation and cardiac remodelling in HF rabbits fed with high-fat diet (HFD).

Methods and results

Twenty-four rabbits randomized into control group fed with regular diet (Control), HFD, HFD-HF, and HFD-HF-RDN groups. Rapid ventricular pacing of 400 b.p.m. for 4 weeks was applied in HFD-HF and HFD-HF-RDN. Surgical and chemical RDNs were approached through bilateral retroperitoneal flank incisions in HFD-HF-RDN. All rabbits received electrophysiological study and a VF inducibility test. The ventricular myocardium was harvested for trichrome stain. After 3 months, mean body weight was heavier in HFD, compared with control (3.5 ± 0.1 kg vs. 2.6 ± 0.1 kg, P &lt; 0.01). No differences in body weight among the three groups fed with HFD were observed. The ventricular refractory periods were longer in HFD-HF and HFD-HF-RDN than in control. An extension of ventricular fibrosis was observed in HFD and HFD-HF compared with control, and the degree of ventricular fibrosis was suppressed in HFD-HF-RDN compared with HFD-HF. The level of tyrosine hydroxylase staining was reduced in HFD-HF-RDN compared with HFD and HFD-HF. Importantly, VF inducibility was lower in HFD-RDN-HF (10 ± 4%), when compared with those in HFD-HF (58 ± 10%, P &lt; 0.01) and HFD (42 ± 5%, P &lt; 0.05), respectively.

Conclusion

Our results suggest that overweight and HF increase sympathetic activity, structural remodelling, and VF inducibility, but RDN prevents them.

Gastroesophageal reflux disease and atrial fibrillation: Insight from autonomic cardiogastric neural interaction

BACKGROUND

The relationship between gastroesophageal reflux disease (GERD) and atrial fibrillation (AF) has been previously reported. However, the detailed mechanism remains unknown. In this study, we investigated the effects of acid reflux on the intrinsic cardiac autonomic nervous system, atrial/ventricular electrophysiology, and AF inducibility.

METHODS

Eighteen rabbits were randomized into three groups: acid reflux (group 1, n = 6), control (group 2, n = 6), and acid reflux with periesophageal vagal blockade (group 3, n = 6). Atrial and ventricular effective refractory periods (ERPs) and AF inducibility were checked at baseline and then hourly until 5 hours after the experiment.

RESULTS

Three hours after the experiment, atrial ERP prolongation was noted in groups 2 and 3 (P < .05), whereas shortening of the atrial ERPs was observed in group 1, compared with the baseline. However, no changes were observed in ventricular ERPs in the three groups. The AF inducibility was higher in group 1 than in groups 2 and 3. Pathological examination showed clear esophageal mucosal breaks in groups 1 and 3.

CONCLUSIONS

In this study, we found that the antimuscarinic blockade prevents GERD induced changes to atrial electrophysiology and susceptibility to AF-making it highly likely that autonomic activity is important in mediating this effect.

Ultra-rapid high-density mapping system with the phase singularity technique is feasible in identifying rotors and focal sources and predicting AF termination

INTRODUCTION

Phase singularity (PS) mapping provides additional insight into the AF mechanism and is accurate in identifying rotors. The study aimed to evaluate the feasibility of PS mapping in identifying AF rotors using data obtained from an automatic ultra-rapid high-resolution mapping system with a high-density mini-basket catheter.

METHODS

Twenty-three pigs underwent rapid right atrial (RA) pacing (RAP 480 bpm) for 5 weeks before the experiment. During AF, RA endocardial automatic continuous mappings with a mini-basket catheter were generated using an automatic ultra-rapid mapping system. Both fractionation mapping and waveform similarity measurements using a PS mapping algorithm were applied on the same recording signals to localize substrates maintaining AF.

RESULTS

Seventeen (74%) pigs developed sustained AF after RAP. Three were excluded because of periprocedural ventricular arrhythmia and corrupted digital data. RA fractionation maps were acquired with 6.17 ± 4.29 minutes mean acquisition time, 13768 ± 12698 acquisition points mapped during AF from 581 ± 387 beats. Fractionation mapping identified extensively distributed (66.7%) RA complex fractionated atrial electrogram (CFAE), whereas the nonlinear analysis identified high similarity index (SI > 0.7) parts in limited areas (23.7%). There was an average of 1.67 ± 0.87 SI sites with 0.43 ± 0.76 rotor/focal source/chamber. AF termination occurred in 11/16 (68.75%) AF events in 14 pigs during ablation targeting max CFAE. There was a higher incidence of rotor/focal source at AF termination sites compared with non-AF termination sites (54.5% vs 0%, P = 0.011).

CONCLUSIONS

The data obtained from ultra-rapid high-density automatic mapping is feasible and effective in identifying AF rotors/focal sources using PS technique, and those critical substrates were closely related to AF procedural termination.

Beneficial Effect of Renal Denervation on Ventricular Premature Complex Induced Cardiomyopathy

Background

Frequent ventricular premature complexes (VPCs) can lead to the development of dilated cardiomyopathy and sudden cardiac death. Renal artery sympathetic denervation (RDN) may protect the heart from remodeling. This study aimed to investigate the effect of frequent VPCs on structural and electrical properties and whether RDN can protect the heart from remodeling.

Methods and Results

Eighteen rabbits were randomized to control (n=6), VPC (n=6), and VPC‐RDN (n=6) groups. Surgical and chemical RDNs were approached through bilateral retroperitoneal flank incisions in the VPC‐RDN group. Pacemakers were implanted to the left ventricular apex to produce 50% VPC burden for 5 weeks in the VPC and VPC‐RDN groups. In addition, ventricular myocardium was harvested for western blot and trichrome stain. Echocardiographic results showed left ventricular enlargement after 5‐week pacing in the VPC group, but not in the VPC‐RDN group, when compared to baseline. In biventricles, ion channel protein expressions of Nav1.5, Cav1.2, Kir2.1, and SERCA2 were similar among 3 groups. However, the degree of biventricular fibrosis was extensive in the VPC group, compared to the control and VPC‐RDN groups. Importantly, ventricular fibrillation inducibility was higher in the VPC group (41%) when comparing to the control (13%; P<0.05) and VPC‐RDN groups (13%; P<0.05), respectively.

Conclusions

Frequent VPCs are associated with the development of cardiac structural remodeling and high ventricular fibrillation inducibility. RDN prevents cardiac remodeling and the occurrence of ventricular arrhythmia through antifibrosis.

Temporary Suppression of Cardiac Ganglionated Plexi Leads to Long-Term Suppression of Atrial Fibrillation: Evidence of Early Autonomic Intervention to Break the Vicious Cycle of "AF Begets AF"

BACKGROUND

Botulinum toxin (BTX), temporarily suppressing cholinergic transmission (<3 weeks), has been reported to suppress atrial fibrillation (AF) for ≥1 year. We aimed to investigate the mechanism underlying long-term suppression of AF caused by injecting BTX into major atrial ganglionated plexi (GPs).

METHODS AND RESULTS

Bilateral thoracotomies in anesthetized dogs allowed programmed stimulation at 4 pulmonary veins, biatrial appendages, and the superior vena cava to determine the effective refractory period (ERP) in the first operation. Group 1 (n=10) received BTX injection into all GPs; group 2 (n=7) received no injection. Groups 1 and 2 received rapid atrial pacing (800 bpm) 6 days a week. Group 3 (n=7) did not undergo thoracotomy or rapid atrial pacing to serve as controls for histological studies. A second operation and the same measurements were made 3 months later. During the first operation in group 1, ERPs of 4 pulmonary veins, but not biatrial appendages or superior vena cava, increased immediately after BTX injection. AF burdens increased significantly from the fifth week after the first operation in group 2 but not in group 1. In the second operation, ERPs remained unchanged compared with ERPs before BTX injection in group 1, whereas ERPs shortened significantly at all sites except the superior vena cava in group 2. There was no difference of autonomic nerve density between group 1 and group 3. The GP choline acetyltransferase (+) and atrial tyrosine hydroxylase (+) nerve densities were higher in group 2 than in group 1 and group 3.

CONCLUSIONS

Temporary suppression of major atrial GPs by BTX prevents autonomic remodeling and provides long-term suppression of AF, indicating the critical role of GPs in AF progression.

Effect of vagotomy on the activity of cardiac autonomic ganglia: Insight from left atrial high density frequency mapping

BACKGROUND

Both extrinsic and intrinsic cardiac autonomic nervous systems are important for initiation and maintenance of atrial fibrillation (AF). We aimed to evaluate the effect of vagotomy on the activity of cardiac autonomic ganglionated plexi (GP) and the change of dominant frequency (DF) distribution in the left atrium (LA) during AF.

METHODS

A mid-sternal thoracotomy was performed in 6 dogs. High frequency stimulation was applied to locate the GPs. There were four major LA GPs, which were located near the pulmonary vein ostia, and a superior vena cava-aorta (SVC-Ao) GP that was located near the superior vena cava-right atrial junction. Acetylcholine patch was applied on GPs to induce intrinsic vagal response. Vagal denervation was performed thereafter. An Ensite Array was deployed in the LA to record atrial signals before and after vagotomy during induced AF.

RESULTS

The LA mean DF values (8.2±0.1 vs. 7.6±0.1Hz, p=0.002) were higher during GP activation before than after vagotomy. The maximal DF distribution was located at the primary GPs and the nearby secondary GPs during LA GPs activation and at the LA septum and right superior pulmonary vein during SVC-Ao GP activation before vagotomy. After vagotomy, the maximal DF distribution shifted to non-GP LA sites during activation of the GPs.

CONCLUSIONS

The findings suggest the important role of the extrinsic neural input in the activation and interaction of the intrinsic cardiac autonomic activity during cholinergic AF, whereas the non-GP LA sites were responsible for the AF induced without the physiological extrinsic neural input.

Dynamic contrast-enhanced and T2-weighted magnetic resonance imaging study of the correlation between tumour angiogenesis and growth kinetics

Accumulating evidence indicates that tumour growth is angiogenesis-dependent. Non-invasive assessment of the relationship between tumour growth and associated angiogenesis is essential for diagnosis and for therapeutic interventions. We utilized a combination of high-resolution T2-weighted and dynamic contrast-enhanced magnetic resonance imaging to investigate the dynamics of angiogenesis during tumour growth in a mouse tumour model expressing Epstein-Barr virus-encoded latent membrane protein 1 isolated from a nasopharyngeal carcinoma in Taiwan. Serial imaging acquisitions were performed starting on the third day after subcutaneous implantation of tumours, through day 28. We observed a progressive increase in tumour volume until day 14, followed by rapid and exponential growth. The volume transfer constant, K(trans), also increased significantly on day 14, and then gradually decreased, suggesting that the angiogenic switching occurs prior to significant tumour growth. At the initial stage, the K(trans) values were significantly higher in the tumour peripheral region than in the tumour core, but, during tumour growth, the K(trans) values in the region between the tumour periphery and core gradually increased, becoming larger than those of the periphery. These results demonstrate that the ability to perform repeated measurements assessing the correlation between tumour growth kinetics and tumour angiogenesis makes it possible to determine the critical time of angiogenic switching prior to rapid tumour growth, as well as suggesting the timing of therapy.

Arsenite-induced cytotoxicity in dorsal root ganglion explants

Peripheral neuropathy is common in people chronically overexposed to arsenic. We studied sodium arsenite (arsenite)-induced cytotoxicity in dorsal root ganglion (DRG) explants. Incubation with arsenite concentration- and time-dependently increased the expression of stress proteins, heat shock protein 70, and heme oxygenase-1 in DRG explants. Furthermore, apoptosis was involved in the arsenite-induced cytotoxicity in the treated DRG. Elevation in cytosolic cytochrome c levels and reduction in procaspase 3 levels suggested an involvement of the mitochondrial pathway in arsenite-induced apoptosis in this preparation. At the same time, increases in the activating transcription factor-4 and C/EBP homologous protein and reduction in procaspase 12 levels indicated activation of the endoplasmic reticulum (ER) pathway in the arsenite-induced cytotoxicity in DRG explants. Salubrinal (30 microM), an ER inhibitor, was found to attenuate arsenite-induced DNA fragmentation and reduction in procaspase 12 in DRG explants. Cytotoxic effects by arsenite, sodium arsenate (arsenate), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were compared, and the potency was as follows: arsenite >>> arsenate>MMA and DMA. Recombinant adenovirus vectors encoding glial-cell-derived neurotrophic factor (AdGDNF) genes allowed a stable delivery of GDNF genes to the infected cells in DRG explants. Applied in this manner, AdGDNF was found to inhibit arsenite-induced DNA fragmentation in DRG explants. Moreover, AdGDNF attenuated the arsenite-induced reduction in procaspases 3 and 12 levels. Taken together, our study demonstrates that arsenite is capable of inducing cytotoxicity in DRG explants. Both ER and mitochondria pathways are involved in the arsenite-induced apoptosis in DRG explants. Glial-cell-derived neurotrophic factor appears to be protective against arsenite-induced peripheral neuropathy.

Organ-specific toxicokinetics and dose-response of arsenic in tilapia Oreochromis mossambicus

We appraised organ-specific toxicokinetics and dose responses of arsenic burdens in tilapia Oreochromis mossambicus. We kinetically linked an Area-under-the-curve (AUC)-based acute toxicity model and a pharmacodynamic model to derive dose-response relationships between equilibrium organ-specific arsenic concentrations and mortality effects. The AUC-based acute toxicity model was also used to derive organ-specific internal effect concentration (IEC)-time-response relationships, which can also be applied to predict a time-mortality profile. We conducted a 7-day exposure experiment to obtain toxicokinetic parameters, whereas the AUC-based acute toxicity model was verified with LC50(t) data obtained from a 7-day acute toxicity bioassay. Our results demonstrated that 96-hour LC50 and incipient LC50 for tilapia exposed to arsenic are 28.68 (95% confidence interval to 24.92 to 32.44) and 25.55 mg L(-1), respectively. Dose-response relationships followed the Hill equation, which could be expressed as organ-specific bioconcentration factors and incipient LC50. Organ-specific dose-response relationships showed that muscle, gill, and liver have a relatively steep sigmoid dose-response profile in that IEC50 were 26.6, 62.5, and 78.5 microg g(-1) dry wt (dw), respectively. Organ-specific arsenic internal lethal burdens were the highest in the gill and the lowest in the muscle in waterborne-exposed tilapia. The IEC and target-organ concentrations derived in this study can be used in site-specific risk assessment.

Methicillin-resistant Staphylococcus aureus bacteraemia in neonatal intensive care units: an analysis of 90 episodes

AIM

To delineate the clinical features of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia in infants hospitalized at the neonatal intensive care unit.

METHODS

Episodes of MRSA bacteraemia in Chang Gung Children's Hospital neonatal intensive care unit from 1997 to 1999 were reviewed for incidence, predisposing factors, clinical presentations, treatment and outcome.

RESULTS

Ninety episodes of MRSA bacteraemia were identified. The overall rate of MRSA bacteraemia was 1.05 per 1000 patient days during the 3-y period. Most of the patients were premature infants (76%), with prior operation or invasive procedures (39%), had an indwelling intravascular catheter (79%) and exposure to antibiotic therapy (96%). A localized cutaneous infection was found in 53.3% of the episodes. The most common clinical diagnoses were catheter-related infections (54.4%), skin and soft tissue infections (21.1%), bacteraemia without a focus (20%) and pneumonia (16.7%). Metastatic infection occurred in 18% of these infants. Among the patients treated with vancomycin for < or = 14 d, 88.7% did not develop any complications, and 11.3% developed a recurrence.

CONCLUSIONS

MRSA is an established pathogen in our NICU. MRSA bacteraemia in the neonates predominantly presented as catheter-related infections, and metastatic infections were not infrequently seen. In uncomplicated MRSA bacteraemia, treatment with vancomycin for < or = 14 d seems to be adequate.

Mechanical hemolysis in a hemodialysis patient with carotid-jugular arteriovenous fistula

Renal anemia is mainly caused by inadequate synthesis of erythropoietin from diseased kidneys. At the present time, recombinant human erythropoietin (rHuEPO) is used to correct anemia successfully in most patients with end-stage renal diseases. Nevertheless, poor response to rHuEPO still exists in some hemodialysis patients and its mechanism in some cases remains obscure. Herein, we describe a rare case of rHuEPO hyporesponsiveness due to mechanical hemolysis induced by a traumatic carotid-jugular arteriovenous fistula (AVF) in the presence of subclinical aluminum intoxication. Following surgical resection of the traumatic AVF and 8 months of desferrioxamine treatment, the responsiveness to rHuEPO was restored and the rHuEPO dose requirements reduced.

A review of environmental and economic regulations for promoting industrial waste recycling in Taiwan

The objective of this paper is to present a compilation of recent Taiwan government laws/regulations to promote industrial waste recycling. The description is thus centered on legislation/regulations concerning general industrial wastes recycling in the policies of environmental protection, economic incentives and engineering technologies (3E) that have become effective since 2001. The regulatory system, including Waste Disposal Act, Resource Recycling/Reuse Act, Environmental Basis Law, and Statute for Upgrading Industries, not only gives financial incentives, but also provides technical assistance and information transfer on promoting industrial waste recycling. In order to further utilize the recyclable resources and upgrade the environmental technology, Taiwan's Environmental Protection Administration (EPA), in cooperation with the Ministry of Economic Affairs (MOEA), has jointly ventured some promotion programs, which highlight an Industrial Waste Exchange Information Center and Environmental Technology Park Development Program, also described in the paper.

Measurement of serum vitamin E isomers in fullterm and preterm infants

BACKGROUND

This study was conducted with the following aims: (1) to construct a methodology by high-performance liquid chromatography (HPLC) to measure vitamin E levels in our neonatal units; (2) to establish a reference range of serum vitamin E levels in fullterm neonates and their mothers; and (3) to compare these to levels in the preterm group.

METHODS

During a 6-month period from September 1996 to February 1997, cord blood of 34 uneventful fullterm neonates (gestational age 38-42 weeks, birth weight 2840-3530 g) and venous blood of their healthy mothers were collected. Venous blood of 35 preterm neonates (gestational age 28-34 weeks, birth weight 940-1980 g) was collected at the same time. Serum vitamin E levels were measured by HPLC. The serum vitamin E/total lipids ratio was also examined.

RESULTS

Serum levels of alpha-tocopherol in 34 fullterm neonates and their mothers were 0.212+/-0.127 and 1.160+/-0.513 mg/dl, and of gamma-tocopherol were 0.029+/-0.019 and 0.214+/-0.122 mg/dl, respectively. All fullterm neonates except 2 had serum levels less than 0.5 mg/dl. There was a positive relationship between serum E levels and total lipids. In addition, the correlation between neonatal vitamin E/total lipids ratios and maternal vitamin E/total lipids ratio was statistically significant. The serum level of alpha-tocopherol in 35 preterm infants was 0.170+/-0.090 mg/dl and that of gamma-tocopherol was 0.020+/-0.015 mg/dl; both levels were much lower than those of their fullterm counterparts. But the vitamin E/total lipids ratios did not significantly differ.

CONCLUSIONS

We conclude that (1) measurement of serum vitamin E levels by the HPLC method is practical, and is useful in evaluating deficiencies in preterm infants and possibly useful in monitoring the adequacy after supplementation in future study, and (2) preterm infants had a much lower level of serum tocopherol, but no difference was seen in vitamin E/total lipids ratio.

Comparison of hand-assisted laparoscopic nephroureterectomy with open surgery for upper urinary tract tumor

Herein we report on our initial experience in performing nephroureterectomy by hand-assisted laparoscopic surgery, and compare the results with those performed by traditional open methods. From December 2000 to September 2001, 10 patients with upper urinary tract tumors underwent hand-assisted laparoscopic nephroureterectomy. Except for one patient who required elective conversion to open surgery due to renal vein injury, this cohort of 9 patients was compared to a group of 35 patients who had received traditional open nephroureterectomy over the last 2 years. Demographic, intraoperative and postoperative data were compared retrospectively. These two groups were similar in age, body mass index, operation time and time to postoperative oral intake. However, the hand-assisted laparoscopy group was found to have significantly less blood loss, less need for parenteral narcotic and a shorter length of time needed for postoperative hospitalization than the open group. Thus, in this report we have demonstrated hand-assisted laparoscopic nephroureterectomy to be a safe and efficacious treatment of malignant urinary collecting tumors. We believe the benefits of this minimally invasive surgery make it a viable alternative technique for management of upper urinary tract tumor.

Hereditary hemorrhagic telangiectasia: demonstration of portosystemic venous shunts using power Doppler sonography and sonographically guided percutaneous transhepatic portovenography

Hereditary hemorrhagic telangiectasia is a rare autosomal dominant inherited disease associated with vascular abnormalities, which may occur in any organ. Cases of hereditary hemorrhagic telangiectasia accompanied by intrahepatic portosystemic venous shunts, however, have rarely been described. We report a case of hereditary hemorrhagic telangiectasia in which intrahepatic portosystemic shunts were detected using power Doppler sonography and portovenography with percutaneous transhepatic contrast agent injection. On gray-scale sonography, the common hepatic artery was dilated, and dilated tubular structures mimicking dilated biliary tracts were found. Power Doppler sonography demonstrated the continuity of tortuous vascular channels connecting a branch of the right portal vein to a branch of the right hepatic vein. The dilated vascular channels and tributaries of the right hepatic vein showed a monophasic waveform pattern on spectral analysis. Portovenography showed a tangle of vascular structures connecting with a branch of the right hepatic vein.

HLA-DRB1 antigens in Taiwanese patients with juvenile-onset systemic lupus erythematosus

OBJECTIVE

This study was done to investigate the frequency of HLA-DRB1 antigens in juvenile-onset systemic lupus erythematosus (SLE) in the Taiwanese population.

PATIENTS AND METHODS

Thirty-four Taiwanese patients with juvenile onset SLE and 200 unrelated healthy controls were studied. HLA-DRB1 typing was performed with polymerase chain reaction (PCR) and the sequence-specific oligonucleotide probe (SSO) typing method.

RESULT

Among the 14 investigated DRB1 alleles, the frequency of HLA-DRB1*1602 was higher in juvenile onset SLE patients than the controls (15.15% vs 4.50%, odds ratio 3.66, 95% confidence interval 1.15-11.68, Pc = 0.04). Although there were differences in the frequencies of DRB1*0301, DRB1*0803, and DRB1*1501 between patients and controls, the associations were statistically insignificant.

CONCLUSION

The frequency of HLA-DRB1*1602 was significantly higher in patients with juvenile onset SLE than in healthy controls. This finding differs from those in the previous studies in Caucasian and Japanese adult onset SLE patients.

Stepwise logistic regression analysis of tumor contour features for breast ultrasound diagnosis

To assist the ultrasound (US) differential diagnosis of solid breast tumors by using stepwise logistic regression (SLR) analysis of tumor contour features, we retrospectively reviewed 111 medical records of digitized US images of breast pathologies. They were pathologically proved benign breast tumors from 40 patients (i.e., 40 fibroadenomas) and malignant breast tumors from 71 patients (i.e., 71 infiltrative ductal carcinomas). Radiologists, before analysis by the computer-aided diagnosis (CAD) system, segmented the tumors manually. The contour features were calculated by measuring the radial length of tumor boundaries. The features selection process was accomplished using a stepwise analysis procedure. Then, an SLR model with contour features was used to classify tumors as benign or malignant. In this experiment, cases were sampled with "leave-one-out" test methods to evaluate the SLR performance using a receiver operating characteristic (ROC) curve. The accuracy of our SLR model with contour features for classifying malignancies was 91.0% (101 of 111 tumors), the sensitivity was 97.2% (69 of 71), the specificity was 80.0% (32 of 40), the positive predictive value was 89.6% (69 of 77), and the negative predictive value was 94.1% (32 of 34). The CAD system using SLR can differentiate solid breast nodules with relatively high accuracy and its high negative predictive value could potentially help inexperienced operators to avoid misdiagnoses. Because the SLR model is trainable, it could be optimized if a larger set of tumor images were supplied.

Auditory brainstem evoked potentials in healthy full-term and pre-term infants

BACKGROUND

Auditory brainstem evoked potentials (ABEP) are used to evaluate the integrity of auditory pathways. Since there are difficulties in the performance and still no reference ranges for pre-term infants in Taiwan, the purpose of this study was to evaluate the characteristics of ABEP in full-term and pre-term infants.

METHODS

Forty full-term and 52 pre-term infants were enrolled between January and December 1997. ABEP study was performed at 3-7 days after birth, 3, 6 and 12 months of age in the full-term group while the pre-term infants were assessed at 34-36 weeks of gestational age, at term age, and at 3, 6, 12 months of corrected age. Acoustic stimulation of mixed frequency rarefaction clicks was presented to each ear through earphones. The clicks were presented at an intensity of 70-90 dB (hearing level) and a gradual decrement of intensity to 20-40 dB to determine the threshold. Electrical activity was picked up by surface electrodes. Latency of peaks I, III, V, inter-peak latency I-III, III-V, I-V and the threshold were assessed.

RESULTS

In the full-term group, the peak and inter-peak latencies decreased with age. In the pre-term group, the responses of 70 dB stimulus intensity were 53.8%, 58%, 82.8%, 88.9%, 100% in the sequence and the threshold of response decreased with age.

CONCLUSION

There are maturational changes after birth in both full-term and pre-term infants. We conclude that ABEP study is a sensitive, non-invasive tool for the evaluation of auditory pathway in infants.

Sonographic appearance of lipoma of the inferior vena cava

Lipomas of the major central veins are rare, and their sonographic features have rarely been reported. We report a case in which a lipoma of the inferior vena cava (IVC) was incidentally identified during liver sonography in a 68-year-old man. Sonography of the upper abdomen revealed coarsening of the liver echotexture, with a relatively small liver and atrophy of the right hepatic lobe. A 2-cm hypoechoic hepatic nodule was visualized in segment IV. Sonography also showed a 2.2- x 1.8-cm, highly echogenic, homogeneous nodule in the hepatic segment of the IVC at its junction with the right atrium. The lumen of the IVC was partially occluded. The CT and MRI appearances of the IVC lesion were consistent with a lipoma, which was not treated because there was no clinical evidence of obstruction. Histopathologic analysis following a sonographically guided biopsy of the liver nodule revealed hepatocellular carcinoma, which was treated by percutaneous ethanol injection.

Fluconazole therapy in neonatal candidemia

We reviewed 62 episodes (from 59 infants) of neonatal candidemia that occurred between January 1994 and June 1999. Except 5 term babies, all infants were premature (median gestational age [GA], 30 weeks) and birth weight was less than 2,500 g (median, 1,300 g). Most infants had reported risk factors and other neonatal problems. The age at onset of candidemia ranged from 15 to 173 days with a median of 34 days. In addition to catheter removal, all but one infants received antifungal agents and candidemia was eradicated subsequently in 46 episodes (75%). Eighteen infants with 19 episodes ever received fluconazole therapy. Fluconazole was administered as the first line agent in 6 episodes and successfully cleared candidemia in 5 episodes. Fluconazole was used as an alternative agent in an additional 13 episodes after amphotericin B (am B) +/- flucytosine were given for a period without a satisfactory result and eradication of candidemia was achieved in 8 episodes subsequently. All 18 infants tolerated fluconazole well and no withdrawal was required on account of its adverse effect. In contrast, am B alone was administered as the first line agent in 55 episodes and successfully cleared candidemia in 32 episodes (58%). This retrospective analysis suggests that fluconazole appears to be safe in neonates and can be used as an alternative agent in treating neonatal candidemia. A large-scaled prospective study may be needed.

Hepatocellular carcinoma associated with focal nodular hyperplasia. Report of a case with clonal analysis

We describe a hepatocellular carcinoma partially surrounded by focal nodular hyperplasia in a 65-year-old female patient. In order to clarify the relationship of the hepatocellular carcinoma and the adjacent focal nodular hyperplasia, clonal analysis was conducted. The clonal analysis was based on the methylation pattern of the polymorphic X-chromosome-linked androgen receptor gene (HUMARA). The allelic bands from the amplification of the focal nodular hyperplasia and of the hepatocellular carcinoma showed a significant reduction in the intensity of one of the two alleles as compared with two alleles of equal intensity in the buff coat after HhaI digestion, which indicated that these two parts were monoclonal. However, the inactivated allele in the focal nodular hyperplasia and that in the hepatocellular carcinoma were not identical. Therefore, the focal nodular hyperplasia and hepatocellular carcinoma probably derived from the clonal expansion of two different clones.

Sonographic features of xanthogranulomatous pyelonephritis

PURPOSE

The purpose of this study was to describe the various sonographic features of xanthogranulomatous pyelonephritis (XGP).

METHODS

We retrospectively reviewed the CT, sonographic, and medical records of patients diagnosed with XGP from January 1981 to December 1998. Twenty-seven patients for whom XGP was histopathologically confirmed were included in the study. There were 12 men and 15 women, with an age range of 21-86 years (mean, 57 years). All patients had undergone sonography of the kidneys. The renal size, shape, and outline were recorded. The presence of perinephric fluid accumulation, of obstructive uropathy, or of internal echoes in the dilated collecting system and the echotexture of the renal parenchyma were documented.

RESULTS

We categorized the XGP into 4 groups on the basis of the sonographic features: (1) diffuse hydronephrotic, 12 patients (44%); (2) diffuse parenchymal, 9 patients (33%); (3) diffuse contracted, 4 patients (15%); and (4) segmental or focal, 2 patients (7%). A localized perinephric fluid collection was present in 4 patients (15%). The preoperative sonographic diagnoses were pyonephrosis (n = 14, 52%), renal pelvic tumor with possible associated infection (n = 5, 19%), renal parenchymal mass (n = 2, 7%), hydronephrosis (n = 2, 7%), and chronic pyelonephritis with renal atrophy (n = 4, 15%). XGP was considered a possible diagnosis in only 11 patients (41%).

CONCLUSIONS

XGP has no specific sonographic features but is suggested by parenchymal thinning and hydronephrosis, sonographic signs of chronic obstructive uropathy caused by stones; echoes in the dilated collecting system; and a perinephric fluid collection. CT, needle biopsy, or both are recommended to further evaluate and confirm sonographically suspected XGP.

The role of high-resolution ultrasonography in management of calcific tendonitis of the rotator cuff

This article predicts the possibility of resorption of the calcific plaques in the shoulder using high-resolution ultrasonography (HRUS) and color Doppler ultrasound (CDUS), and evaluates the therapeutic effect of US-guided fine-needle multiple punctures of the calcific plaque. A total of 100 patients with calcific tendenosis were divided into 3 groups: In group 1, patients having chronic shoulder pain received conservative treatment; in group 2, patients having acute exacerbation of shoulder pain also received conservative treatment; and group 3 patients received US-guided fine-needle multiple punctures or aspiration. In CDUS, all images were classified as grade 0 (no color flow signals), grade 1 (weak spotty color flow signal), grade 2 (few rod-like color flow signals), grade 3 (many rod-like or linear color flow signals). In the follow-up study, marked improvement of patients' clinical condition with more than 50% size reduction of calcific plaque was defined as an effective treatment. There was no significant difference between group 1 and group 3 (p = 0.558) in CDUS, but there was a significant difference between group 1 and group 2 (p = 0.000), and group 2 and group 3 (p = 0.000) on the basis of classification of grade < 1 and grade > or = 1. There was also significant difference in the follow-up result of effective management between group 1 and group 3 (p = 0.000), and group 1 and group 2 (p = 0.000). In conclusion, HRUS with CDUS proved to be a good modality in evaluating the possibility of resorption of shoulder calcification and, if CDUS > or = grade 1 in calcific tendonitis, we highly recommend conservative treatment with regular follow-up. On the other hand, if CDUS < grade 1, fine-needle repeated puncture could be considered as an effective alternative treatment.

Hand-assisted laparoscopic radical nephrectomy of renal cell carcinoma--a case report

A 62-year-old female patient with chronic medical history of DM and hypertension was admitted due to traffic accident. She was asymptomatic until 5 days before admission. She was referred to our medical center with an abdominal CT revealing left renal tumor. The diameter of the renal mass was 50 mm. On ultrasonographic examination, a heterogenous lesion over the left kidney was noted. Renal scanning showed a cold nodule in the left kidney. Hand-assisted laparoscopic transperitoneal radical nephrectomy was performed smoothly. The kidney was removed from the hand port in the supraumbilical skin incision with a volume of 14 x 7 x 6 cm3 and weight of 570 gm. The operation time was 5 hours, blood loss was 200 cc, and no significant change of blood pressure was noted during the surgery. The patient's postoperative course was uneventful. The pathological report of this mass was renal cell carcinoma.

Mitotic reorganization of the intermediate filament protein nestin involves phosphorylation by cdc2 kinase

The intermediate filament protein nestin is expressed during early stages of development in the central nervous system and in muscle tissues. Nestin expression is associated with morphologically dynamic cells, such as dividing and migrating cells. However, little is known about regulation of nestin during these cellular processes. We have characterized the phosphorylation-based regulation of nestin during different stages of the cell cycle in a neuronal progenitor cell line, ST15A. Confocal microscopy of nestin organization and (32)P in vivo labeling studies show that the mitotic reorganization of nestin is accompanied by elevated phosphorylation of nestin. The phosphorylation-induced alterations in nestin organization during mitosis in ST15A cells are associated with partial disassembly of nestin filaments. Comparative in vitro and in vivo phosphorylation studies identified cdc2 as the primary mitotic kinase and Thr(316) as a cdc2-specific phosphorylation site on nestin. We generated a phosphospecific nestin antibody recognizing the phosphorylated form of this site. By using this antibody we observed that nestin shows constitutive phosphorylation at Thr(316), which is increased during mitosis. This study shows that nestin is reorganized during mitosis and that cdc2-mediated phosphorylation is an important regulator of nestin organization and dynamics during mitosis.