Impact of crystalline orientation on Cu-Cu solid-state bonding behavior by molecular dynamics simulations

High-density electronics are hindered by the constraints of Sn-based solder joints, necessitating the exploration of Cu-Cu solid-state bonding. However, current bonding methods are expensive and time-consuming; therefore, understanding the Cu-Cu bonding mechanism is crucial for optimization. This study utilizes molecular dynamics (MD) simulation to elucidate the Cu-Cu solid-state bonding behavior, focusing on interfacial densification and diffusion phenomena. Furthermore, it highlights the influence of crystal orientation on the interfacial bonding behavior. To analyze the impact of crystal orientation, monocrystalline Cu slabs with a simplified periodic surface structure were employed to replicate surface roughness and subsequently bonded at a specific temperature. The results indicate the critical influence of crystalline orientations on the bonding process: identical orientations result in slower densification at the interface, whereas misoriented orientations significantly accelerate it. This effect, attributed to the grain boundary (GB) structures formed owing to misorientation, suggests a central role for GB diffusion in bonding progression. Diffusion coefficients calculated using the mean square displacement (MSD) confirmed these findings and exhibited significantly larger values for misoriented joints. Additionally, the simulations reveal an activation energy for GB diffusion that is lower than conventional values, highlighting the impact of the crystallographic orientation and voids at the bonding interface. Our research elucidates the role of crystalline orientation in diffusion phenomena at bonding interfaces, offering valuable implications for optimizing bonding-based manufacturing processes.

Thermomechanical Properties of Zeta (Ag3In) Phase

The thermomechanical properties of materials within die-attach joints play an essential role in assessing the reliability of high-power modules. Ag-In transient liquid phase (TLP) bonding serves as an alternative method for die attachment. However, relevant material data for the ζ (Ag3In) phase, one of the Ag-In intermetallic compound (IMC) products of TLP bonding, are limited. This paper proposes an approach to fabricate a densified and pure bulk sample of the ζ (Ag3In) phase. The thermomechanical properties of the ζ (Ag3In) phase were subsequently investigated at elevated temperatures and compared to those of other IMCs frequently observed in die-attach joints. As the temperature increased from 30 °C to 200 °C, the hardness of the ζ (Ag3In) phase decreased linearly from 1.78 GPa to 1.46 GPa. Similarly, the Young's modulus also decreased linearly from 82.3 GPa to 66.5 GPa. These properties rank among the lowest levels compared to those of other IMCs. The average coefficient of thermal expansion within the temperature range of 70 °C to 250 °C was approximately 18.63 ± 0.61 μm/m/°C, placing the ζ (Ag3In) phase at a moderate level. When considering its potential for mitigating thermal stress, these combined properties render the ζ (Ag3In) phase an appropriate material choice for die-attach joints compared to other IMCs.

Influence of Isothermal Aging on Microstructure and Shear Property of Novel Epoxy Composite SAC305 Solder Joints

With the rapid iteration of microsystem integrated technology, the miniaturization of electronic devices requires packaging materials with higher reliability. In this work, the microstructure evolution and mechanical properties of novel epoxy composite SAC305 solder joints were studied after isothermal aging to evaluate the enhanced effect of epoxy addition. The thickness variation and morphological evolution of the interfacial layer were analyzed. The results showed that, as the aging time was prolonged, the Cu6Sn5 interfacial layer remarkably coarsened and Cu3Sn compounds formed between the Cu6Sn5 layer and Cu pad due to the continuous atomic diffusion. Compared with the monolithic joint, the epoxy composite SAC305 joints had a lower overall IMC growth rate during aging, closely related to the initial morphologies of the interfacial layers. The shear test results showed an apparent decrease in the shear forces of all the solder joints as the aging time increased. Nevertheless, because of the extra mechanical support provided by the epoxy layer, the epoxy composite joints demonstrated notably enhanced mechanical properties. After 1000 h aging treatment, the shear force of SAC305 joints containing 8 wt.% epoxy was 26.28 N, showing a 24.08% increase over the monolithic joint. Cu-Sn IMCs were detected on the shear fracture of the monolithic joint after 1000 h aging, indicating the fracture occurred near the interface and displayed a ductile/brittle mixed fracture. Concerning the epoxy composite joints, cracks were still initiated and extended within the solder bulk, demonstrating a noticeable enhancement in ductility due to the addition of epoxy.

Solid-state bonding behavior between surface-nanostructured Cu and Au: a molecular dynamics simulation

In recent years, solid-state bonding has attracted attention for various electronic packaging applications as an alternative to conventional solders. Surface-nanostructured materials enable solid-state bonding without complex surface modifications and operate at a low bonding temperature and pressure. Therefore, in this study, molecular dynamics simulations were conducted to investigate the solid-state bonding behavior between surface-nanostructured Cu and Au, with a focus on diffusion phenomena. A periodic ligament-cavity nanostructured Cu (NS-Cu) model was prepared at the bonding interface between Cu and Au slabs. The simulation results indicated that the larger the specific surface area of NS-Cu, the faster the densification at the bonding interface. Atomic displacement analysis showed that rapid densification occurred via the displacement of Cu and Au atoms in the vicinity of NS-Cu. The preferential diffusion of atoms along NS-Cu cavities contributed to this phenomenon. At this stage of densification, the diffusion coefficients were higher than the surface diffusion coefficients estimated based on literature, which indicates that this behavior is specific to surface-nanostructured materials. The highly disordered atomic arrangement at the bonding interface enabled significant atomic diffusion. Therefore, this study confirmed that the use of surface-nanostructured materials would contribute to a promising bonding technology for application in electronics.

Prognostic value of high-sensitive troponin T for predicting cardiovascular events after atrial fibrillation ablation

BACKGROUND AND OBJECTIVES

This study aimed to evaluate the utility of high-sensitive troponin T (hs-TnT) for predicting AF recurrence and major adverse cardiovascular events (MACE) after AF ablation.

METHODS AND RESULTS

A total of 227 consecutive patients with AF (mean age, 66 ± 10 years; persistent AF, n = 98) who underwent an initial ablation were enrolled. We measured hs-TnT before AF ablation and divided the patients into three groups according to the hs-TnT level: low, lesser than or equal to 0.005 µg/L (n = 54); medium, 0.006-0.013 µg/L (n = 127); and high, greater than or equal to0.014 µg/L (n = 46). We evaluated the composite endpoint of AF recurrence or MACE (including death, stroke, acute coronary syndrome, and heart failure hospitalization) after the ablation. The median hs-TnT level was 0.008 µg/L. The values of chronic kidney disease prevalence, CHA₂ DS₂ -VASc score, B-type natriuretic peptide level, and left atrial diameter were the highest in the high hs-TnT group among the three groups. During a mean follow-up of 15 ± 8 months, AF recurrence and MACE occurred in 56 (25%) and 9 (4%) patients, respectively. The high hs-TnT group had the highest incidence of AF recurrence and MACE among the three groups (high: 39% and 15%, medium: 22% and 2%, and low: 19% and 0%, respectively; log-rank P < .05). In multivariate analysis, hs-TnT greater than or equal to 0.014 µg/L and persistent AF were independent predictors of the composite endpoint.

CONCLUSION

Hs-TnT may be a useful marker for predicting AF recurrence or MACE after AF ablation.

Multiple coronary artery spasms triggering life-threatening ventricular arrhythmia associated with the radiofrequency ablation of ganglionated plexuses of the left atrium

We report a case of multiple coronary spasms leading to life-threatening ventricular arrhythmia, during left atrium (LA) ablation. Coronary artery spasm is a rare complication during radiofrequency catheter ablation of atrial fibrillation (AF). Previous reports mention that autonomic imbalance leads to coronary artery spasm and ST-segment elevation in the inferior leads, during trans-septal LA catheterization and AF ablation procedures. However, there are few reports detailing the association between ablation sites and changes in the electrocardiogram. We encountered transient ST-segment elevation and refractory ventricular arrhythmia, associated with coronary artery spasm, during radiofrequency ablation of ganglionated plexuses (superior surface of left and right atrium). <Learning objective: Our case report shows that ablation of ganglionated plexus sites during pulmonary vein isolation, can induce ST-segment elevation in various leads, and cause multiple coronary spasms associated with refractory ventricular fibrillation. There is an inherent risk of multiple coronary spasms during catheter ablation of atrial fibrillation (AF), in patients with vasospastic angina. We recommend continuous intravenous infusion of nitroglycerin during ablation for AF to prevent coronary spasms in patients with vasospastic angina.>.

The Use of Electronic Medical Record Data to Analyze the Association Between Atrial Fibrillation and Birth Month

OBJECTIVES

Cardiovascular disease is a condition of enormous public health concern. Recently, a population study newly revealed associations between cardiovascular diseases and birth month. Here, we investigated the association between atrial fibrillation in cardiovascular disease and birth month.

METHODS

We retrospectively extracted birth date data from 6,016 patients with atrial fibrillation (3,876 males; 2,140 females) from our electronic medical records. The number of live births in Japan fluctuates seasonally. Therefore, we corrected the number of patients for each birth month based on a Japanese population survey report. Then, a test of the significance of the association between atrial fibrillation and birth month was performed using a chi-square test. In addition, we compared the results of an analysis of patient data with that of simulated data that showed no association with birth month.

RESULTS

The deviations of birth month were not significant (overall: p = 0.631, males: p = 0.842, females: p = 0.333). The number of female patients born in the first quarter of the year was slightly higher than those born in the other quarters of the year (p = 0.030). However, by comparing the magnitudes of dispersion in the simulated data, it seems that this finding was mere coincidence.

CONCLUSION

An association between atrial fibrillation and birth month could not be confirmed in our Japanese study. However, this might be due to differences in ethnicity. Further epidemiologic studies on this topic may result in reduction of disease risk in the general population and contribute to public health.

Impact of simple electrocardiographic markers as predictors for deterioration of left ventricular function in patients with frequent right ventricular apical pacing

Several trials demonstrated that frequent right ventricular apical pacing (RVAP) was associated with cardiac dysfunction and an increased rate of heart failure hospitalization. However, there are few reports about the 12-lead electrocardiogram (12-ECG) parameters at the time of device implantation to predict deterioration of LVEF in patients with frequent RVAP. We retrospectively studied 115 consecutive patients undergoing pacemaker or implantable cardioverter-defibrillator implantation with RVAP, with rate of ventricular pacing ≥ 40% and LVEF ≥ 50% at the time of implantation. We compared the 12-ECG characteristics at the time of device implantation between patients with deterioration of LVEF (≥ 10% reduction) and those without. Twenty-nine patients (25%) had deteriorated LVEF with a decrease in mean LVEF from 59 to 40% during a median follow-up period of 8.9 [4.6-13.7] years. Multivariate logistic regression analysis showed that cumulative % of ventricular pacing [odds ratio (OR) 1.04 per 1% increase, 95% confidence interval (CI) 1.01-1.09, p = 0.04], notching of baseline paced QRS in limb leads (OR 5.04, 95% CI 1.59-19.6, p = 0.005) and the QS pattern in all precordial leads (OR 3.56, 95% CI 1.21-10.8, p = 0.02) were independently associated with deterioration of LVEF. The QS pattern of baseline paced QRS in all precordial leads had 58% sensitivity, 93% specificity for the RV lead position at the tip of RV apex. In conclusion, considering OR by multivariate analysis, notching of baseline paced QRS in limb leads and the QS pattern in all precordial leads at device implantation may be simple and useful predictors to identify patients who are at risk for deterioration of cardiac function during long-term RVAP. 12-ECG monitoring at device implantation and avoidance of the RVAP site showing a QS pattern may be important to prevent deterioration of cardiac function in patients with frequent RVAP.

Incidence and predictors of silent cerebral thromboembolic lesions after catheter ablation for atrial fibrillation in patients treated with direct oral anticoagulants

There are few reports about the incidence and predictors of silent cerebral thromboembolic lesions (SCLs) after atrial fibrillation (AF) ablation in patients treated with direct oral anticoagulants (DOACs). The purpose of this study is to evaluate the incidence and predictors of SCLs after AF ablation with cerebral magnetic resonance imaging (C-MRI) in patients treated with DOACs. We enrolled 117 consecutive patients who underwent first AF ablation and received DOACs, including apixaban, dabigatran, edoxaban, and rivaroxaban. DOACs were discontinued after administration 24 h before the procedure, and restarted 6 h after the procedure. During the procedure, activated clotting time (ACT) was measured every 15 min, and intravenous heparin infusion was performed to maintain ACT at 300-350 s. All patients underwent C-MRI the day after the procedure. SCLs were detected in 28 patients (24%) after AF ablation. Age, female sex, the presence of persistent AF, left atrial volume, procedure time, radiofrequency energy, electrical cardioversion, and mean ACT showed no correlations with the incidence of SCLs. Multivariate analysis revealed independent predictors of SCLs were CHA₂DS₂VASc scores ≥3, left atrial appendage (LAA) emptying velocity ≤39 cm/s, and minimum ACT ≤260 s. Patients with both CHA₂DS₂VASc scores ≥3 and LAA flow velocity ≤39 cm/s had the highest incidence of SCLs 15 of 26 patients (58%). In patients treated with DOACs, CHA₂DS₂VASc score ≥3, minimum ACT ≤260 s, and LAA emptying velocity ≤39 cm/s were independent risk factors for the SCLs after AF ablation.

A case of unexpected early battery depletion caused by lithium cluster formation in implantable cardioverter-defibrillator

Device failure from unexpected battery depletion is uncommon but can be life-threatening. Lithium cluster formation at the cathode is a novel mechanism of sudden implantable cardioverter-defibrillator (ICD) battery depletion that was first reported in 2014. We report a rare case of a 78-year-old woman with an ICD battery failure due to lithium cluster formation. Although she had never received ICD therapy, the battery voltage had dropped from 2.9 V to 2.54 V (end of life) unexpectedly for only 2 days. The prevalence of this rare phenomenon was reported to be 0.004% in 2014. However, it had gone up to 0.21% in October 2016. Both device manufacturers and clinicians should be aware of this phenomenon, and remote monitoring systems and vibratory patient notifier alerts should be considered for early detection and early treatment. <Learning objective: Lithium cluster formation is a novel mechanism of premature ICD battery depletion that was first reported in 2014. Although the prevalence of this rare phenomenon was first reported as 0.004% in 2014, according to the data of St. Jude Medical, it had gone up to 0.21% in October 2016. We should be aware of this rare but important phenomenon and use remote monitoring systems and vibratory patient notifier alerts for early detection and treatment.>.

Utility of T-wave alternans during night time as a predictor for ventricular fibrillation in patients with Brugada syndrome

The prognostic value of T-wave alternans (TWA) during the night time in patients with Brugada syndrome (Br-S) remains unknown. We assessed TWA for risk stratification using 24-h multichannel Holter electrocardiogram (24-M-ECG) in Br-S. We enrolled 129 patients with Br-S [grouped according to histories of ventricular fibrillation (VF), n = 16; syncope, n = 10; or no symptoms (asymptomatic), n = 103] and 11 controls. Precordial electrodes were attached to the third (3L-V1, 3L-V2) and fourth (4L-V1, 4L-V2 and 4L-V5) intercostal spaces. We measured the values of maximum TWA (max-TWA) during the night time (12 a.m.-6 a.m.) and the day time (12 p.m.-6 p.m.) and calculated parameters of heart rate variability. Compared to the asymptomatic and control groups, the VF and syncope groups showed significantly greater 3L-V2 max-TWA during the night time. The cutoff value for the 3L-V2 max-TWA during the night time was determined as 20 µV (sensitivity 94 % and specificity 48 %; p = 0.01). Multivariate analysis revealed that 3L-V2 max-TWA during the night time ≥20 µV and previous VF episodes were independent predictors of future VF episodes. During a mean follow-up period of 68 ± 37 months, 16 patients experienced VF episodes. The incidence of VF episodes was the highest during the night time (p < 0.001). The 3L-V2 max-TWA during the night time may be a useful predictor for VF episodes in patients with Br-S.

Mechanosensitive channels are activated by stress in the actin stress fibres, and could be involved in gravity sensing in plants

Mechanosensitive (MS) channels are expressed in a variety of cells. The molecular and biophysical mechanism involved in the regulation of MS channel activities is a central interest in basic biology. MS channels are thought to play crucial roles in gravity sensing in plant cells. To date, two mechanisms have been proposed for MS channel activation. One is that tension development in the lipid bilayer directly activates MS channels. The second mechanism proposes that the cytoskeleton is involved in the channel activation, because MS channel activities are modulated by pharmacological treatments that affect the cytoskeleton. We tested whether tension in the cytoskeleton activates MS channels. Mammalian endothelial cells were microinjected with phalloidin-conjugated beads, which bound to stress fibres, and a traction force to the actin cytoskeleton was applied by dragging the beads with optical tweezers. MS channels were activated when the force was applied, demonstrating that a sub-pN force to the actin filaments activates a single MS channel. Plants may use a similar molecular mechanism in gravity sensing, since the cytoplasmic Ca(2+) concentration increase induced by changes in the gravity vector was attenuated by potential MS channel inhibitors, and by actin-disrupting drugs. These results support the idea that the tension increase in actin filaments by gravity-dependent sedimentation of amyloplasts activates MS Ca(2+) -permeable channels, which can be the molecular mechanism of a Ca(2+) concentration increase through gravistimulation. We review recent progress in the study of tension sensing by actin filaments and MS channels using advanced biophysical methods, and discuss their possible roles in gravisensing.

New candidates for mechano-sensitive channels potentially involved in gravity sensing in Arabidopsis thaliana

The mechano-sensitive channels of plants may sense increases in tension induced by mechanical stimuli, such as touch, wind and turgor pressure, and a gravitational stimulus. Recent studies have identified plant homologues of the bacterial mechano-sensitive channel MscS, which is gated by membrane tension and reduces intracellular osmolality by releasing small osmolytes from bacterial cells. However, the physiological roles of these homologues have not yet been clearly elucidated, and only two of them have been shown to be involved in the protection of osmotically stressed plastids in Arabidopsis thaliana. We identified another group of candidates for mechano-sensitive channels in Arabidopsis, named MCA1 and MCA2, whose homologues are exclusively found in plant genomes. MCA1 and MCA2 are composed of 421 and 416 amino acid residues, respectively, share 73% homology in their amino acid sequences, and are not homologous to any known ion channels or transporters. Our structural study revealed that the N-terminal region (one to 173 amino acids) of both proteins was necessary and sufficient for Ca(2+) influx activity. Interestingly, this region had one putative transmembrane segment containing an Asp residue whose substitution mutation abolished this activity. Our physiological study suggested that MCA1 expressed at the root tip was required for sensing the hardness of the agar medium or soil. In addition, MCA1 and MCA2 were shown to be responsible for hypo-osmotic shock-induced increases in [Ca(2+) ]cyt . Thus, both proteins appear to be involved in the process of sensing mechanical stresses. We discussed the possible role of both proteins in sensing mechanical and gravitational stimuli.

Evaluation of primary prophylaxis with granulocyte colony-stimulating factor for epithelial ovarian cancer

PURPOSE

Primary prophylaxis with G-CSF has been used to minimize myelosuppression caused by anticancer agents and to avoid severe neutropenia. The authors retrospectively examined the value of primary prophylaxis using granulocyte colony-stimulating factor (G-CSF) for epithelial ovarian cancer.

MATERIALS AND METHODS

From 2001 to 2010, 105 patients with ovarian cancer receiving chemotherapy in the present hospital were divided into two groups: one received primary prophylaxis with G-CSF and the other did not receive it in compliance with the guidelines for G-CSF usage. The incidence of febrile neutropenia (FN), degree of neutropenia, frequency of G-CSF administration, number of days of hospitalization, progression-free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

Neutrophils decreased almost equally and the length of hospitalization was not significantly lower between the groups. Five-year PFS or OS showed no significant difference either.

CONCLUSIONS

Primary prophylaxis with G-CSF in chemotherapy for epithelial ovarian cancer could be of low significance.

Outcome of fertility-sparing treatment with medroxyprogesterone acetate for atypical hyperplasia and endometrial carcinoma in young Japanese women

PURPOSE

To review the outcome in patients with atypical endometrial hyperplasia (AEH) and endometrial cancer (EC) who received MPA treatment in the present hospital.

MATERIALS AND METHODS

Patients with AEH or EC were administered MPA for 12 weeks followed by endometrial curettage. The rates of effect, recurrence, pregnancy, and complications were evaluated. The changes in progesterone receptors and FOXO-1, known as a target of MPA treatment, were examined by immunostaining.

RESULTS

Four of seven patients with endometrial cancer and three of three patients with AH had complete response. Four of seven patients had recurred within one year after the treatment and had to undergo hysterectomy. None of the patients showed changes in progesterone receptors. Although six of seven patients were negative for FOXO-1 before and after treatment, all the patients showed increased developments of FOXO-1 during MPA treatment.

CONCLUSION

Progestin as a fertility-preserving treatment is expected to be effective for endometrial cancer, but judicious use might be required because it shows high rate of recurrence. Further studies regarding the mechanism may be necessary to achieve high efficacy.

The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures

We evaluated the safety, efficacy, and morbidity associated with the treatment of displaced mandibular condylar neck fractures using a retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates. Our surgical inclusion criteria were: patient selection of open reduction and fixation, displaced unilateral condylar fractures with derangement of occlusion, and bilateral condylar fractures with an anterior open bite. The study group consisted of 19 patients who underwent surgery for 19 mandibular condylar neck fractures; patients were analyzed prospectively, with more than 6 months of follow-up, and were evaluated in terms of functional results, scar formation, postoperative complications, and stability of fixation. The results showed that functional occlusion identical to the preoperative condition and correct anatomical reduction of the condylar segments in centric occlusion, followed by immediate functional recovery, was achieved in all patients. No patient suffered from any major or permanent complication postoperatively, although there were two cases (11%) of temporary facial nerve palsy, which resolved completely within 3 months. Surgical scars were barely visible. The retromandibular transparotid approach with open reduction and rigid internal fixation for displaced condylar neck fractures of the mandible is a feasible and safe, minimally invasive surgical technique that provides reliable clinical results.

Asialoglycoprotein receptor scintigraphy with 99mTc-galactosyl human serum albumin (99mTc-GSA) as an early predictor of survival in acute liver failure

This study evaluated the usefulness of asialoglycoprotein receptor scintigraphy with 99mTc-galactosyl human serum albumin (99mTc-GSA scintigraphy) as an early predictor for prognosis of acute liver failure. Forty-eight patients with acute liver failure and without a past history of chronic liver disease were enrolled. Patients were divided into survival and non-survival groups by 28-day mortality. 99mTc-GSA scintigraphy to detect uptake ratio of the heart at 15 minutes to that at three minutes (HH15) and uptake ratio of the liver at 15 minutes to the liver plus the heart at 15 minutes (LHL15), and measurements of serum total bilirubin, hepatocyte growth factor and prothrombin time were performed immediately after the diagnosis of acute liver failure. Areas under the receiver operating characteristic curves were used to compare the prognostic ability of total bilirubin, hepatocyte growth factor, prothrombin time, HH15 ratio, LHL15 ratio and the model for end-stage liver disease score. Clinical characteristics of patients in the survival group (n=20) and in the non-survival group (n=28) were not significantly different. HH15 and LHL15 uptake ratios in the survival group were 0.670 and 0.875, and they were significantly lower and higher than those in the non-survival group, respectively. All patients with LHL15 <0.760 died, and the area under the receiver operating characteristic curve for LHL15 were significantly larger than the areas under the receiver operating characteristic curves of serum variables and model for end-stage liver disease score. In summary, in patients with acute liver failure without chronic liver disease, HH15 and LHL15 of 99mTc-GSA scintigraphy are more useful variables in predicting prognosis than serum variables and model for end-stage liver disease score.

Lymphoepithelial-like carcinoma of the uterine cervix; a case report

Lymphoepithelioma-like carcinoma (LELC) of the uterine cervix is a rare variant of squamous cell carcinoma of the uterine cervix. This tumor is characterized by nests of poorly differentiated epithelial cells surrounded by a prominent lymphocytic infiltration. Despite the poorly differentiated pathological findings, it appears to have a better outcome than the usual squamous cell carcinoma of the uterine cervix. Therefore, it is quite important to differentiate this tumor from poorly differentiated squamous cell carcinoma and lympho-proliferative disorders of the cervix. LELC arising from the nasopharynx has been suggested to be associated with Epstein-Barr virus (EBV), whereas the involvement of EBV in LELC of the uterine cervix is still controversial. In addition, the role of high-risk human papilloma virus (HPV) in this type of tumor remains unknown. We report a case of LELC of the cervix with diagnosis on the basis of histopathology in a 52-year-old Japanese woman who presented with a history of continuous bleeding post menopause. We also examine the association of EBV and HPV in this case.

Platypnea-orthodeoxia diagnosed by sitting transesophageal echocardiography

Platypnea-orthodeoxia is a rare syndrome presenting with dyspnea and cyanosis induced by an upright position and relieved by recumbency. We report a patient with an excessively enlarged aortic root who had critical hypoxia due to a paradoxical shunt through the patent foramen ovale only when seated. The postural changes of the shunt, caused by changes in posture, were dynamically detected by transesophageal Doppler echocardiography. We believe that this syndrome should be considered when patients with aortic root dilatation present with inexplicable hypoxia, and that transesophageal Doppler echocardiography in the sitting position can be useful for detecting platypnea-orthodeoxia syndrome.

A predictor of positive drug provocation testing in individuals with saddle-back type ST-segment elevation

BACKGROUND

A drug provocation test is performed to unmask a type 1 electrocardiogram (ECG) in individuals with saddle-back type ST-segment elevation in the right precordial leads (SB-ECG). The study investigated predictors of positive responders (PR) by drug testing.

METHODS AND RESULTS

A total of 58 consecutive individuals with SB-ECG in lead V2 were enrolled and drug testing was performed. In leads V2 at standard and the third intercostal space (V2(IC3)), the QRS duration was measured, the amplitudes of r' wave (r'), ST-segment 20 and 40 ms after the r' wave (r'20 and r'40, respectively), the bottom of the ST-segment (ST(b)), the differences between r' and r'20 (r'-r'20), r' and r'40 (r'-r'40), r' and ST(b) (r'-ST(b)), and the descending rate of the ST-segment [(r'-r'20)/r'; DR20, (r'-r'20)/(r'-ST(b)); DR20-ST(b)] were also measured. Thirty-five PR had significantly longer QRS duration, larger r'20 and r'40, and smaller r'-r'20, DR20, and DR20-ST(b) than negative responders. DR20 and DR20-ST(b) in leads V2 and V2(IC3) were most significantly different between 2 groups. The positive and negative predictive values of ;DR20-ST(b) in lead V2(IC3) <0.62' for prediction of positive tests were 92.3% and 81.8%, respectively.

CONCLUSIONS

In individuals with SB-ECG, DR20 and DR20-ST(b) in leads V2 and V2(IC3) might be useful predictors of positive testing.

Usefulness of multichannel Holter ECG recording in the third intercostal space for detecting type 1 Brugada ECG: comparison with repeated 12-lead ECGs

INTRODUCTION

Type 1 Brugada ECG is essential for the diagnosis of Brugada syndrome. We aimed to evaluate the usefulness of multichannel Holter ECG recording in the third intercostal space for detecting type 1 Brugada ECG.

METHODS AND RESULTS

We enrolled 60 consecutive individuals with type 1 Brugada ECG and 31 individuals with type 2 or 3 Brugada ECG, in the presence or absence of Na+ channel blockers. All individuals underwent 12-lead ECGs recorded in the standard position and the third intercostal space at least 5 times every 3 months (4L-ECGs, 3L-ECGs, respectively) and multichannel Holter ECG. On multichannel Holter ECG, the precordial electrodes were attached at standard positions (4L-Holter) and the third intercostal space (3L-Holter) for leads V1 and V2. Among the 60 individuals, type 1 Brugada ECG in 4L-ECGs, 3L-ECGs, 4L-Holter, and 3L-Holter was detected in 15 (25%), 26 (43.3%), 23 (38.3%), and 33 individuals (55%), respectively, whereas detected in none of the 31 individuals. The documented duration of type 1 Brugada ECG on 3L-Holter was significantly longer than that on 4L-Holter (700 +/- 467 vs 372 +/- 422 min; P = 0.01, 3L-Holter vs 4L-Holter, respectively), and type 1 Brugada ECG was most frequently observed between 6 pm and 12 pm. Neither the presence nor the duration of the appearance of type 1 Brugada ECG differed significantly between symptomatic and asymptomatic individuals.

CONCLUSION

Multichannel Holter ECG recording in the third intercostal space is more sensitive and useful for the diagnosis of type 1 Brugada ECG than repeated 12-lead ECGs or multichannel Holter ECG in the standard position.

The effects of nifekalant hydrochloride on the QT dispersion after direct-current defibrillation

BACKGROUND

Although nifekalant hydrochloride (NIFE) has been demonstrated to suppress ventricular tachyarrhythmia, especially electrical storm, the mechanism by which it does so is still unclear. We examined its effects on the spatial dispersion of repolarization (SDR) after implantable cardioverter-defibrillator (ICD) shock.

METHODS AND RESULTS

In twenty five patients with an ICD, we recorded the 87-lead ECG during sinus rhythm (the CONTROL group) under general anesthesia, after NIFE administration alone, and just after termination of induced ventricular fibrillation (VF) by ICD shock with or without NIFE administration. In all recordings, the corrected QT interval (QTc) was measured in each lead. The dispersion of QTc (QTc-D; maximum QTc minus minimum QTc) was also measured. Compared with the CONTROL, the QTc-D exhibited significant deterioration after ICD shock (61 +/- 12, 91 +/- 24 ms(1/2), respectively, p < 0.001). However, the QTc-D after NIFE administration either with or without ICD shock did not differ from the CONTROL group (65 +/- 20, 61 +/- 18, and 61 +/- 12 ms(1/2), respectively, p = 0.99).

CONCLUSIONS

NIFE suppressed the deterioration of SDR by ICD shock. This might be a mechanism by which NIFE suppresses recurrence of ventricular tachyarrhythmia after ICD shock.

Successful radiofrequency catheter ablation for electrical storm of ventricular fibrillation in a patient with Brugada syndrome

The case of a 41-year-old man with Brugada syndrome (BS) who suffered electrical storms (ES) of ventricular fibrillation (VF) is presented. Although intravenous infusion of isoproterenol (ISP) suppressed the VF occurrence, he consistently experienced recurrence of VF following discontinuation of ISP infusion. Quinidine and cilostazol were ineffective. An analysis of VF episodes on electrocardiogram monitoring revealed that the QRS morphology of the first beat of all VF episodes was identical to that of premature ventricular complexes (PVCs) with a left bundle branch-block morphology and inferior axis, which occurred repetitively before the episodes of VF and were recorded throughout the day. In addition, stored electrograms from the implantable cardioverter defibrillator showed that the first beat of all VF episodes had the same morphology. On electrophysiological study, the VF-triggering PVC was found to originate from the posterior portion of the right ventricular outflow tract area and their elimination, which was achieved with radiofrequency catheter ablation (RFCA), resulted in the suppression of ES. Although several other PVCs were still observed, the patient has been free of VF during the 29-month follow-up period. This case indicates that RFCA of VF-triggering PVCs may be useful in the treatment of drug-resistant ES in patients with BS.

Approach to the asymptomatic patients with Brugada syndrome

Brugada syndrome is an arrhythmogenic disease characterized by an ECG pattern of coved-type ST segment elevation in the right precordial leads and an increased risk of sudden cardiac death (SCD) as a result of polymorphic ventricular tachyarrhythmia or ventricular fibrillation (VF). Data from large patient studies and a meta-analysis of previous reports have shown that patients with a history of syncope or SCD and a spontaneous type 1 Brugada type ECG are at high risk for SCD. However, risk stratification of asymptomatic patients with Brugada type ECG is still a challenge. In particular, the use of electrophysiological study (EPS) for risk stratification remains controversial. Although some investigators have reported the possibility of use of EPS for distinguishing between high- and low-risk patients with Brugada type ECG, no precise predictor of risk for SCD in asymptomatic patients has yet been determined. The approach to treatment of these patients is thus still unclear. Large clinical prospective studies with uniform diagnostic criteria and protocols for EPS as well as extended follow-up periods of over ten years are required for prediction of SCD.

Risk Stratification in Patients with Brugada Syndrome: Analysis of Daily Fluctuations in 12-Lead Electrocardiogram (ECG) and Signal-Averaged Electrocardiogram (SAECG)

INTRODUCTION

Risk stratification between symptomatic and asymptomatic patients with Brugada syndrome is not yet established. We compared daily fluctuations in 12-lead electrocardiogram (ECG) and signal-averaged ECG (SAECG) characteristics between symptomatic and asymptomatic patients with Brugada syndrome to identify new markers for distinguishing between high- and low-risk patients.

METHODS AND RESULTS

Thirty-five patients with Brugada syndrome underwent ECG and SAECG simultaneously at least 4 times every 3 months. We evaluated daily fluctuations (differences between maximum and minimum values) in ECG and SAECG characteristics and compared them between symptomatic (N = 11), and asymptomatic (N = 24) patients. On ECG, the daily fluctuations in r-J interval (interval from QRS onset to J point) in leads V1, V2, and V6 were significantly larger in symptomatic than in asymptomatic patients (V1; 20 +/- 6 vs 10 +/- 8 msec, P < 0.01, V2; 22 +/- 8 vs 11 +/- 4 msec, P < 0.01, and V6; 24 +/- 7 vs 14 +/- 7 msec, P < 0.01). On SAECG, daily fluctuations in filtered QRS (f-QRS) duration and LAS40 were significantly larger in symptomatic than in asymptomatic patients (f-QRS; 15 +/- 7 vs 9 +/- 4 msec, P < 0.05, and LAS40; 21 +/- 7 vs 10 +/- 6 msec, P < 0.05).

CONCLUSIONS

Instability of depolarization appears to be related to the risk of fatal ventricular arrhythmias in patients with Brugada syndrome. Daily fluctuations in ECG and SAECG characteristics could be useful for distinguishing between high- and low-risk patients with Brugada syndrome.

Nominal free air in the left inguinal fossa due to perforation of the sigmoid colon in a case of blunt abdominal trauma: CT diagnosis

We present a case of perforation of the sigmoid colon due to blunt abdominal trauma. Computed tomography showed nominal free air in the inguinal fossa. The distribution of free air may be a clue to the site of an injured intestine. Early detection of intestinal injury is difficult, but repeated computed tomography after several hours may reveal increased free air.

Improved bioluminescent enzyme immunoassay for the rapid detection of Salmonella in chicken meat samples

AIMS

To evaluate an improved bioluminescent enzyme immunoassay (BEIA) using biotinylated firefly luciferase for the rapid detection of Salmonella in naturally contaminated chicken meat samples.

METHODS AND RESULTS

Capture agents and lipopolysaccharide (LPS) extraction reagents for Salmonella were investigated to improve the sensitivity of the BEIA. Also, the use of Oxoid SPRINT (Simple Pre-enrichment and Rapid Isolation New Technology) as a pre-enrichment and selective medium for 26-h BEIA detection of Salmonella in chicken meat samples was examined. The use of polymyxin B as a capture agent on solid support and 3-[(3-Cholamidopropyl) dimethylammonio] propanesulfonic acid (CHAPS) for extraction of the LPS facilitated sensitive detection of Salmonella. Of 120 chicken meat samples, 25 samples were positive using the improved BEIA with the SPRINT and 25 samples were positive using the SPRINT followed by the standard isolation methods.

CONCLUSIONS

The improved BEIA, in which polymxin B was used as a capture agent and CHAPS was used for extraction of the antigen, had a sensitivity of 96.0% and a specificity of 98.9% for the detection of Salmonella in chicken meat.

SIGNIFICANCE AND IMPACT OF THE STUDY

The improved BEIA combined with the SPRINT medium for the detection of Salmonella in chicken meat samples produced comparable results to the culture methods in 26 h.

In vitro reconstitution of signal transmission from a hair cell to the growth cone of a chick vestibular ganglion cell

Signal transmission from a chick hair cell to the growth cone of a vestibular ganglion cell was examined by placing an acutely dissociated hair cell on the growth cone of a cultured vestibular ganglion cell. Electrical stimuli were applied to the hair cell while monitoring the intracellular Ca(2+) concentration ([Ca(2+)](i)) at the growth cone or recording whole-cell currents from the vestibular ganglion cell. Electrical stimulation of the hair cell induced [Ca(2+)](i) increases at the growth cone and inward currents in the vestibular ganglion cell. The [Ca(2+)](i) increase was blocked by 6-cyano-7-nitroquinoxaline (CNQX) (10 microM) but not by 2-amino-5-phosphonovaleric acid (APV; 50 microM). Glutamate (100 nM-300 microM) applied to the vestibular ganglion cell by the Y-tube method induced inward currents which were also antagonized by CNQX, but not by APV. These results indicate that the electrical stimulation of a hair cell induced glutamate or glutamate like agent release from the hair cell, which activated non-N-methyl-D-aspartate receptors at the growth cone of the vestibular ganglion cell, followed by action potentials and [Ca(2+)](i) elevation in the vestibular ganglion cell. This is the first demonstration of in vitro reconstitution of functional signal transmission from a hair cell to a vestibular ganglion cell.

Evaluation of a 24-hour bioluminescent enzyme immunoassay for the rapid detection of Salmonella in chicken carcass rinses

A bioluminescent enzyme immunoassay (BEIA), using Salmonella-specific monoclonal antibody M183 for capture and biotinylated monoclonal antibody M183 for detection, was developed with InteLite AB streptavidin-biotinylated firefly luciferase complex as a reporter. Salmonella cultures were preenriched in buffered peptone water with shaking for 6 h at 37 degrees C and then selectively enriched in Muller-Kauffmann tetrathionate (MKTT) broth and modified semisolid Rappaport-Vassiliadis (MSRV) medium for 16 h at 42 degrees C. After enrichment, the total test time for the BEIA was 1.5 h. The analytical sensitivity of the BEIA ranged from 6.0 x 10(2) CFU/ml to 1.2 x 10(5) CFU/ml in MKTT and from 1.4 x 10(5) to 2.3 x 10(6) CFU/ml in MSRV using six Salmonella serovars prevalent in Canada. With enrichment cultures, the BEIA detected 1 CFU of Salmonella Typhimurium and Salmonella Enteritidis in 25 ml of chicken rinses. Representative strains of 10 Salmonella serovars were detected, and cross-reactivity was not observed with 25 non-Salmonella foodborne bacteria. The BEIA performance was assessed by testing 420 poultry samples, which were analyzed in parallel with the standard MSRV culture method. The BEIA detected 117 (27.88%) Salmonella-positive samples, whereas the standard MSRV culture method detected 124 (29.5%). The BEIA had a sensitivity of 64.5% and a specificity of 87.5% compared to the standard MSRV culture method. However, similar specificities and sensitivities were obtained when the standard MSRV culture method was compared to the BEIA (sensitivity = 68.4% and specificity = 85.5%). Neither method detected 100% of the Salmonella found in the samples tested, and statistical analyses indicated no significant difference between the two methods. In summary, the BEIA offers another alternative for the detection of Salmonella, with the additional advantage of providing a 24-h test for detecting Salmonella in chicken carcass rinses. The results obtained in this research indicate that tests are still needed for the isolation and detection of Salmonella that will establish the true prevalence of Salmonella in chicken samples.

Dynamics of integrin clustering at focal contacts of endothelial cells studied by multimode imaging microscopy

Human umbilical vein endothelial cells were stained with FITC-labeled anti-β1 integrin antibody and plated on a glass cover slip to elucidate the mechanism of integrin clustering during focal contact formation. The process of integrin clustering was observed by time-lapse total-internal-reflection fluorescence microscopy, which can selectively visualize the labeled integrins at the basal surface of living cells. The clustering of integrins at focal contacts started at 1 hour after plating and individual clusters kept growing for ∼6 hours. Most integrin clusters (∼80%) elongated towards the cell center or along the cell margin at a rate of 0.29±0.24 μm minute−1. Photobleaching and recovery experiments with evanescent illumination revealed that the integrins at the extending tip of the clusters were supplied from the intracellular space. Simultaneous time-lapse imaging of exocytosis of integrin-containing vesicles and elongating focal contacts showed that most exocytosis occurred at or near the focal contacts followed by their elongation. Double staining of F-actins and integrins demonstrated that stress fibers were located near the integrin clusters and that intracellular punctate integrins were associated with these stress fibers. These results suggest that the clustering of integrins is mediated by actin-fiber-dependent translocation of integrins to the extending tip of focal contacts.

Calcium-sensitive nonselective cation channel identified in the epithelial cells isolated from the endolymphatic sac of guinea pigs

We identified a Ca2+-sensitive cation channel in acutely dissociated epithelial cells from the endolymphatic sac (ES) of guinea pigs using the patch-clamp technique. Single-channel recordings showed that the cation channel had a conductance of 24.0 +/- 1.3 pS (n = 8) in our standard solution. The relative ionic permeability of the channel was in the order K+ = Na+ > Ca2+ >> Cl-. This channel was weakly voltage-dependent but was strongly activated by Ca2+ on the cytosolic side at a concentration of around 1 mm in inside-out excised patches. With cell-attached patches, however, the channel was activated by much lower Ca2+ concentrations. Treatment of the cells, under cell-attached configuration, with ionomycin (10 microm), carbonyl cyanide 3-chlorophenylhydrazone (CCCP, 20 microm), or ATP (1 mm), which increased intracellular Ca2+ concentration ([Ca2+]i), activated the channel at an estimated [Ca2+]i from 0.6 microm to 10 microm. It is suggested that some activators of the channel were deteriorated or washed out during the formation of excised patches. Based on this Ca2+ sensitivity, we speculated that the channel contributes to the regulation of ionic balance and volume of the ES by absorbing Na+ under certain pathological conditions that will increase [Ca2+]i. This is the first report of single-channel recordings in endolymphatic sac epithelial cells.

Internet medical usage in Japan: current situation and issues

Internet use by physicians and patients has become very popular in Japan. Fifty percent of physicians use the Internet to search for medical and other information. Over the past year, 22% of patients used the Internet to obtain medical information. Because there are no restrictions within Japan on using Web sites to advertise medical treatment, information can be freely sent out, and over the past two or three years this practice has increased dramatically. Internet medical information provides information about illnesses and medications, and it helps improve the quality of life of patients and families. Yet, depending on the content of the information provided and the way this information is used, there is a potential negative side as well. On principle, users are responsible for the way information is used, but there is a need for information providers to consider users safety and to make the information effective for use. Because there is no absolute standard for evaluating the value of medical information, it is necessary to establish a system that opens a dialogue with society and that continuously accumulates high-quality information through the collection of various evaluations, rather than rely on an established authority. For industries and organizations related to commercial pursuits, in particular, it is most effective to establish their own codes for ethical conduct, rather than rely on governmental regulations. At the same time, it is important to have a confirmation function to evaluate how goals set by the outside are being implemented. Aiming at establishing a framework for the Internet medical usage, the Japan Internet Medical Association (JIMA) was founded in 1998 by medical professionals, lawyers, researchers, consumer representatives, patients and their families. We propose a system that would combine feedback from users, who would take on the role of evaluators of the implementation of an ethical code, with a displayed mark that verifies the identity of the Web site. Objective evaluation of information is needed to ensure that users have the power to make choices. Medical experts or patient and family groups would assist in this task. The development of medical care will be promoted through patients and physicians working together in the accumulation of shared resources for good medical care information.