A novel bivalent anti-c-MET/PD-1 bispecific antibody exhibits potent cytotoxicity against c-MET/PD-L1-positive colorectal cancer

Previously, we generated a novel bispecific antibody (BsAb) simultaneously targeting both c-MET and PD-1 (PDCD1), which can bridge T cells and c-MET positive tumor cells. However, the specific mechanisms and antitumor activities of the BsAb against c-MET/PD-L1 (CD274) positive colorectal cancer (CRC) is not completely understood. In this study, in addition to the tumor intrinsic mechanism investigation with molecular biology assay in vitro, a humanized mouse model was used to evaluate antitumor activity of the BsAb in vivo. The BsAb could inhibit c-MET/PD-L1+ CRC cell migration and show strong antitumor activity against HCT116 tumors in mice, potentially by inducing the degradation of c-MET protein in a dose and time-dependent manner. The BsAb could suppress the phosphorylation of c-MET downstream proteins GRB2-associated-binding protein 1 (Gab1) and focal adhesion kinase (FAK). Considering the tumor extrinsic mechanism, the BsAb may promote phagocytosis of macrophage. Furthermore, the level of plasma exosomal-c-MET/PD-L1 is able to distinguish CRC patients from healthy controls. In summary, the BsAb exhibited potent anti-tumor activities by two distinguished mechanisms: inhibition of c-MET signal transduction and promotion of macrophage-mediated phagocytosis. Our BsAb may provide a novel therapeutic agent for patients with c-MET/PD-L1+ CRC, and the status of exosomal-c-MET/PD-L1 can serve as a biomarker to predict responsiveness to treatment of our BsAb.

Discrimination of auditory verbal hallucination in schizophrenia based on EEG brain networks

Auditory verbal hallucinations (AVH) are a core positive symptom of schizophrenia and are regarded as a consequence of the functional breakdown in the related sensory process. Yet, the potential mechanism of AVH is still lacking. In the present study, we explored the difference between AVHs (n = 23) and non-AVHs (n = 19) in schizophrenia and healthy controls (n = 29) by using multidimensional electroencephalograms data during an auditory oddball task. Compared to healthy controls, both AVH and non-AVH groups showed reduced P300 amplitudes. Additionally, the results from brain networks analysis revealed that AVH patients showed reduced left frontal to posterior parietal/temporal connectivity compared to non-AVH patients. Moreover, using the fused network properties of both delta and theta bands as features for in-depth learning made it possible to identify the AVH from non-AVH patients at an accuracy of 80.95%. The left frontal-parietal/temporal networks seen in the auditory oddball paradigm might be underlying biomarkers of AVH in schizophrenia. This study demonstrated for the first time the functional breakdown of the auditory processing pathway in the AVH patients, leading to a better understanding of the atypical brain network of the AVH patients.

Prevalence and correlates of depression and anxiety among Chinese international students in US colleges during the COVID-19 pandemic: A cross-sectional study

Background

Previous studies showed that the COVID-19 outbreak increased the levels of depression and anxiety in heterogeneous populations. However, none has explored the prevalence and correlates of depression and anxiety among Chinese international students studying in US colleges during the pandemic.

Objective

This study examines the prevalence of depression and anxiety among Chinese international students enrolled in US universities during the COVID-19 pandemic and identifies the associated factors, including habits, social and psychological support, sleep quality, and remote learning.

Methods

Between June and July 2020, we conducted a cross-sectional study through Wenjuanxing, a web-based survey platform. Participants were recruited with snowball sampling through 21 Chinese international student associations in US universities. The survey consisted of demographic questions, the Social Support Rating Scale (SSRS), the Insomnia Severity Index (ISI), the Patient Health Questionnaire-9 (PHQ-9), the General Anxiety Disorder-7 (GAD-7), and self-constructed questions on academic performance, financial concerns, use of social media, physical exercise, and psychological support. Cut-off scores of 10 were used for both PHQ-9 and GAD-7 to determine the binary outcomes of depression and anxiety, respectively. Bivariant analyses and multivariable logistic regression analyses were performed to identify the associated factors.

Results

Among 1881 participants, we found a prevalence of depression (PHQ-9 score⩾ 10) at 24.5% and that of anxiety (GAD-7 score⩾ 10) at 20.7%. A higher risk of depression was associated with recent exposure to traumatic events, agreement to pandemic’s negative impacts on financial status, agreement and strong agreement to the negative impacts of remote learning on personal relationships, and a higher ISI score. A lower risk of depression was associated with disagreement to the negative impacts of remote learning on academic performance and future careers, strong willingness to seek professional help with emotional issues, and a higher SSRS score. In addition, a higher risk of anxiety was associated with recent exposure to traumatic events, a lot of workloads, often staying up for online classes, agreement and strong agreement to the negative impacts of remote learning on personal relationships, and a higher ISI score. A lower risk of anxiety was associated with the willingness and strong willingness to seek professional help with emotional issues, and a higher SSRS score.

Conclusion

This study showed a high prevalence of depression and anxiety among Chinese international students studying in US colleges during the COVID-19 pandemic. Multiple correlates—including recent exposure to traumatic events, pandemic-related financial concerns, workload, social support, remote learning, willingness to seek professional help, and sleep quality—were identified. It is critical for future studies to further investigate this student population and for universities to provide more flexible learning options and more access to psychological services.

Similarities and Differences in Brain Activation Between Patients With Schizophrenia and Obsessive-Compulsive Disorder: A Near-Infrared Spectroscopy Study

Schizophrenia (SZ) and obsessive-compulsive disorder (OCD) share several epidemiological and clinical features, but the neurobiological substrates shared by these two diseases remain unclear. This study aimed to explore the similarities and differences in brain function between them using near-infrared spectroscopy (NIRS). Eventually, 130 SZ patients, 70 OCD and 75 normal controls (NCs) were enrolled. A 52-channel NIRS instrument was used to detect the concentration changes in oxygenated hemoglobin ([oxy-Hb]) during the verbal fluency task. Ten regions of interests (ROIs) were defined: the bilateral dorsolateral prefrontal cortex (DLPFC), frontopolar cortex (FPC), orbitofrontal cortex (OFC), inferior prefrontal gyrus (IFG) and temporal gyrus (TG). Through two different analysis strategies based on channels or ROIs, we compared the [oxy-Hb] changes in three groups by one-way analysis of variance (ANOVA) and post-hoc tests. Across 52 channels, compared to the NC group, both SZ and OCD groups exhibited reduced activity in 17 channels, including left FPC, left DLPFC, bilateral OFC, IFG, middle TG, supplementary motor cortex and Broca's area, while SZ showed lower activity in channel 35 (right OFC) than OCD patients. Across all ROIs, compared to the NC group, both SZ and OCD groups showed reduced activity in 7 ROIs, including left FPC, bilateral OFC, IFG and TG, while SZ showed lower activity in the right OFC than OCD group, which were almost consistent with the results based on channels. This study suggests SZ and OCD present with some similar neuropathological changes, while SZ shows more severe impairment in the right OFC than OCD.

Optimizing functional near-infrared spectroscopy (fNIRS) channels for schizophrenic identification during a verbal fluency task using metaheuristic algorithms

OBJECTIVE

We aimed to reduce the complexity of the 52-channel functional near-infrared spectroscopy (fNIRS) system to facilitate its usage in discriminating schizophrenia during a verbal fluency task (VFT).

METHODS

Oxygenated hemoglobin signals obtained using 52-channel fNIRS from 100 patients with schizophrenia and 100 healthy controls during a VFT were collected and processed. Three features frequently used in the analysis of fNIRS signals, namely time average, functional connectivity, and wavelet, were extracted and optimized using various metaheuristic operators, i.e., genetic algorithm (GA), particle swarm optimization (PSO), and their parallel and serial hybrid algorithms. Support vector machine (SVM) was used as the classifier, and the performance was evaluated by ten-fold cross-validation.

RESULTS

GA and GA-dominant algorithms achieved higher accuracy compared to PSO and PSO-dominant algorithms. An optimal accuracy of 87.00% using 16 channels was obtained by GA and wavelet analysis. A parallel hybrid algorithm (the best 50% individuals assigned to GA) achieved an accuracy of 86.50% with 8 channels on the time-domain feature, comparable to the reported accuracy obtained using 52 channels.

CONCLUSION

The fNIRS system can be greatly simplified while retaining accuracy comparable to that of the 52-channel system, thus promoting its applications in the diagnosis of schizophrenia in low-resource environments. Evolutionary algorithm-dominant optimization of time-domain features is promising in this regard.

Classification of Schizophrenia by Functional Connectivity Strength Using Functional Near Infrared Spectroscopy

Functional near-infrared spectroscopy (fNIRS) has been widely employed in the objective diagnosis of patients with schizophrenia during a verbal fluency task (VFT). Most of the available methods depended on the time-domain features extracted from the data of single or multiple channels. The present study proposed an alternative method based on the functional connectivity strength (FCS) derived from an individual channel. The data measured 100 patients with schizophrenia and 100 healthy controls, who were used to train the classifiers and to evaluate their performance. Different classifiers were evaluated, and support machine vector achieved the best performance. In order to reduce the dimensional complexity of the feature domain, principal component analysis (PCA) was applied. The classification results by using an individual channel, a combination of several channels, and 52 ensemble channels with and without the dimensional reduced technique were compared. It provided a new approach to identify schizophrenia, improving the objective diagnosis of this mental disorder. FCS from three channels on the medial prefrontal and left ventrolateral prefrontal cortices rendered accuracy as high as 84.67%, sensitivity at 92.00%, and specificity at 70%. The neurophysiological significance of the change at these regions was consistence with the major syndromes of schizophrenia.

Who will benefit from computerized cognitive remediation therapy? Evidence from a multisite randomized controlled study in schizophrenia

BACKGROUND

Computerized cognitive remediation therapy (CCRT) is generally effective for the cognitive deficits of schizophrenia. However, there is much uncertainty about what factors mediate or moderate effectiveness and are therefore important to personalize treatment and boost its effects.

METHOD

In total, 311 Chinese inpatients with Diagnostic and Statistical Manual of Mental Disorders-IV schizophrenia were randomized to receive CCRT or Active control for 12 weeks with four to five sessions per week. All participants were assessed at baseline, post-treatment and 3-month follow-up. The outcomes were cognition, clinical symptoms and functional outcomes.

RESULTS

There was a significant benefit in the MATRICS Consensus Cognitive Battery (MCCB) total score for CCRT (F1,258 = 5.62; p = 0.02; effect size was 0.27, 95% confidence interval 0.04-0.49). There were no specific moderators of CCRT improvements. However, across both groups, Wisconsin Card Sort Test improvement mediated a positive effect on functional capacity and Digit Span benefit mediated decreases in positive symptoms. In exploratory analyses younger and older participants showed cognitive improvements but on different tests (younger on Symbol Coding Test, while older on the Spatial Span Test). Only the older age group showed MSCEIT benefits at post-treatment. In addition, cognition at baseline negatively correlated with cognitive improvement and those whose MCCB baseline total score was around 31 seem to derive the most benefit.

CONCLUSIONS

CCRT can improve the cognitive function of patients with schizophrenia. Changes in cognitive outcomes also contributed to improvements in functional outcomes either directly or solely in the context of CCRT. Age and the basic cognitive level of the participants seem to affect the cognitive benefits from CCRT.

Expression level of lncRNA PVT1 in serum of patients with coronary atherosclerosis disease and its clinical significance

OBJECTIVE

The purpose of this study was to detect the expression level of PVT1 in the serum of coronary artery disease (CAD) patients, and to explore the clinical significance of PVT1 in CAD.

PATIENTS AND METHODS

A total of 200 CAD patients and 200 healthy controls in the same period were included. The serum level of PVT1 in every subject was detected. Then, the correlation between PVT1 level and Gensini score in CAD patients was analyzed by Spearman correlation test. Finally, multivariable Logistic regression test was conducted to assess risk factors influencing coronary atherosclerosis disease.

RESULTS

It was found that PVT1 was highly expressed in the serum of CAD patients and its level was correlated with Gensini score (r=0.761, p=0.023). Besides, multivariable Logistic regression test obtained that PVT1 was the risk factor influencing coronary atherosclerosis disease (crude OR = 2.074, 95% CI: 1.642-3.529; adjusted OR = 1.762, 95% CI: 1.382-2.096).

CONCLUSIONS

Serum level of PVT1 helps to distinguish mild and severe CAD. Meanwhile, PVT1 is an independent risk factor influencing the development of coronary atherosclerosis disease.

Broadband, millimeter-wave antireflection coatings for large-format, cryogenic aluminum oxide optics

We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

Incidence and mortality of nasopharyngeal carcinoma: interim analysis of a cluster randomized controlled screening trial (PRO-NPC-001) in southern China

BACKGROUND

Previous mass screening studies have shown that IgA antibodies against Epstein-Barr Virus (EBV) can facilitate early detection of nasopharyngeal carcinoma (NPC), but the impact of EBV-antibody screening for NPC-specific mortality remains unknown.

PATIENTS AND METHODS

A prospective, cluster randomized, controlled trial for NPC screening (PRO-NPC-001) was conducted in 3 selected towns of Zhongshan City and 13 selected towns of Sihui City in southern China beginning in 2008. Serum samples of the screening group were tested for two previously selected anti-EBV antibodies. Subjects with serological medium risk were subsequently retested annually for 3 years, and those with serological high risk were referred to otorhinolaryngologists for diagnostic check-up. An interim analysis was carried out to evaluate the primary end points of the NPC-specific mortality and the early diagnostic rate, and the secondary end point of the NPC incidence, through linkage with the database of Zhongshan City.

RESULTS

Among 70 296 total subjects, 29 413 screened participants (41.8% of the total subjects) in the screening group and 50 636 in the control group, 153 (43.3 per 100 000 person-year), 62 (55.3 per 100 000 person-year) and 99 (33.1 per 100 000 person-year) NPC cases were identified. The early diagnostic rates of NPC were significantly higher in the participants (79.0%, P < 0.0001) and the screening group (45.9%, P < 0.0001) compared with the control group (20.6%). Although no differences were found between NPC-specific mortality of the screening group and the control group [relative risk (RR)= 0.82, 95% confidence interval (CI) 0.37-1.79], lower NPC-specific mortality was noticed among participants from the screening group versus the control group (RR = 0.22, 95% CI 0.09-0.49).

CONCLUSION

IgA antibodies against EBV can identify high-risk population and was effective in screening for early asymptomatic NPC. Although the mortality reduction was not significant in the primary end point, we noted encouraging evidence of a mortality reduction in screening participants in this interim analysis.

CLINICAL TRIAL NUMBER

NCT00941538.

Reduced prefrontal-temporal cortical activation during verbal fluency task in obsessive-compulsive disorder: A multi-channel near-infrared spectroscopy study

Functional neuroimaging studies by near-infrared spectroscopy (NIRS) have focused on the role of the prefrontal cortex (PFC) in the pathophysiology of obsessive-compulsive disorder (OCD). However, the reported areas in the PFC were inconsistent in OCD, and correlations between hemodynamic response and clinical symptoms have not been investigated. This study aimed to evaluate the hemodynamic response related to the verbal fluency task (VFT) and assess the relationship between activation and clinical status in OCD patients using a 52-channel NIRS with a wide coverage over the prefrontal and temporal cortices. Seventy patients with OCD and 70 age-, gender- and education level-matched healthy control subjects were examined by NIRS. The relative concentration changes of oxygenated hemoglobin ([oxy-Hb]) were measured. The Yale-Brown obsessive-compulsive scale (Y-BOCS) was used to evaluate the severity of OCD symptoms. Compared to healthy controls group, OCD patients showed smaller [oxy-Hb] changes in most areas of the prefrontal and temporal cortex, including the bilateral orbitofrontal cortex (OFC), right dorsolateral prefrontal cortex (DLPFC), bilateral inferior prefrontal cortex (IPFC), bilateral frontopolar cortex (FPC), left superior temporal gyrus (STG), and bilateral middle temporal gyrus (MTG). Furthermore, the [oxy-Hb] changes in the right FPC were negatively correlated with the Y-BOCS obsessions score and Y-BOCS total score, and the [oxy-Hb] changes in the left OFC were negatively correlated with the Y-BOCS compulsions score. These results suggest that patients with OCD have reduced prefrontal-temporal cortex hemodynamic responses, and that the abnormalities of brain activation were associated with the severity of OCD symptoms.

The underlying mechanism of deficits of speech comprehension and hallucinations in Chinese patients with schizophrenia

Sentence context and fundamental frequency (F0) contours are important factors to speech perception and comprehension. In Chinese-Mandarin, lexical tones can be distinguished by the F0 contours. Previous studies found healthy people could use the cue of context to recover the phonological representations of lexical tones from the altered tonal patterns to comprehend the sentences in quiet condition, but can not in noise environment. Lots of research showed that patients with schizophrenia have deficits of speech perception and comprehension. However, it is unclear how context and F0 contours influence speech perception and comprehension in patients with schizophrenia. This study detected the contribution of context and lexical tone to sentence comprehension in four types of sentences by manipulating the context and F0 contours in 32 patients with schizophrenia and 33 healthy controls. The results showed that (1) in patients with schizophrenia, the interaction between context and F0 contour was not significant, which was significant in healthy controls; (2) the scores of sentences with two types of sentences with flattened F0 contours were negatively correlated with hallucination trait scores; (3) the patients with schizophrenia showed significantly lower scores on the intelligibility of sentences in all conditions, which were negatively correlated with PANSS-P. The patients with schizophrenia couldn't use the cue of context to recover the phonological representations of lexical tones from the altered tonal patterns when they comprehend the sentences, inner noise may be the underlying mechanism for the deficits of speech perception and comprehension.

Automatic schizophrenic discrimination on fNIRS by using complex brain network analysis and SVM

Background

Schizophrenia is a kind of serious mental illness. Due to the lack of an objective physiological data supporting and a unified data analysis method, doctors can only rely on the subjective experience of the data to distinguish normal people and patients, which easily lead to misdiagnosis. In recent years, functional Near-Infrared Spectroscopy (fNIRS) has been widely used in clinical diagnosis, it can get the hemoglobin concentration through the variation of optical intensity.

Methods

Firstly, the prefrontal brain networks were constructed based on oxy-Hb signals from 52-channel fNIRS data of schizophrenia and healthy controls. Then, Complex Brain Network Analysis (CBNA) was used to extract features from the prefrontal brain networks. Finally, a classier based on Support Vector Machine (SVM) is designed and trained to discriminate schizophrenia from healthy controls. We recruited a sample which contains 34 healthy controls and 42 schizophrenia patients to do the one-back memory task. The hemoglobin response was measured in the prefrontal cortex during the task using a 52-channel fNIRS system.

Results

The experimental results indicate that the proposed method can achieve a satisfactory classification with the accuracy of 85.5%, 92.8% for schizophrenia samples and 76.5% for healthy controls. Also, our results suggested that fNIRS has the potential capacity to be an effective objective biomarker for the diagnosis of schizophrenia.

Conclusions

Our results suggested that, using the appropriate classification method, fNIRS has the potential capacity to be an effective objective biomarker for the diagnosis of schizophrenia.

A QTL with Major Effect on Reducing Stripe Rust Severity Detected From a Chinese Wheat Landrace

Stripe rust, a devastating disease of wheat worldwide, can be controlled by use of diverse wheat resistance resources. To find new quantitative trait loci (QTL) for resistance to stripe rust, Qing Shumai (a Chinese winter wheat landrace possessing slow rusting resistance) was crossed with the susceptible line Mingxian 169. The parents and 276 recombinant inbred lines (RILs) from the cross were evaluated in five environments involving two locations (Gansu and Shandong provinces, China) and four autumn-sown wheat seasons (2008 to 2012). Disease severities on Qing Shumai were lower than 25%, contrasting with approximately 90% on Mingxian 169. The RILs varied in rust intensity in a continuous and monomodal distribution. A bulked segregant analysis approach using 2,344 simple sequence repeat (SSR) markers mapped a major QTL to the long arm of chromosome 6D (hereby designated as QYr.cau-6DL). An SSR marker (gpw5179, https://wheat.pw.usda.gov/GG2/index.shtml ) was identified as being tightly linked with QYr.cau-6DL. Combination between QYr.cau-6DL and the stripe rust-resistance gene Yr18 was examined using 160 F_2:3 families of Qing Shumai × RL6058 (a near-isogenic line for Yr18 in the genetic background of the spring wheat Thatcher). The combination elevated the resistance consistently across both winter and spring wheat backgrounds, acting synergistically without undesired epistasis.

Electrophysiological basis of reading related phonological impairment in Chinese speakers with schizophrenia: An ERP study

It has been reported in alphabetic languages that individuals with schizophrenia showed language-related cognitive impairments including phonological deficits, which were in turn associated with clinical symptoms such as auditory hallucinations and thought disorders. To date, however, the phonological deficits involved in schizophrenia in Chinese and its neural basis have not been well established. In order to establish such a relationship we conducted a behavioral study using lexical tone judgment and digit span tasks as well as an event-related potential (ERP) study with an auditory oddball paradigm, in particular, for P300 effects, the event-related brain potential (ERP) index of discrimination. Chinese patients with schizophrenia and Chinese healthy controls in China participated in the current study. Compared to the healthy controls, the patients with schizophrenia showed significant impairments in phonological processing skills, which in turn significantly correlated with smaller P300 effects. Thus these behavioral and electrophysiological findings in Chinese patients with schizophrenia were critically evaluated in terms of their phonological processing abilities.

Fiber-optic current sensor with self-compensation of source wavelength changes

We demonstrate a method for self-compensation of scale factor changes of an interferometric fiber-optic current sensor caused by source wavelength shifts, e.g., due to changes in source temperature or drive current. An adequately tailored fiber-optic retarder in the optical circuit introduces wavelength-dependent mixing of the orthogonal polarization modes of the sensor. The resulting change in scale factor balances the variation of the Faraday effect with wavelength. The wavelength dependence of the sensor is suppressed by more than an order of magnitude to <0.2% over wavelength spans of at least 10 nm around 1305 nm. The retarder is designed as an athermal device for operation between -40°C and 80°C.

Facile preparation of free-standing rGO paper-based Ni–Mn LDH/graphene superlattice composites as a pseudocapacitive electrode

A novel film electrode was assembled via a simple filtration process, with an rGO paper as the substrate and Ni–Mn LDH/graphene superlattice composites as the functional layer.

Lexical and sub-lexical reading skills and their correlation to clinical symptoms in young Chinese patients with schizophrenia

Patients with schizophrenia often experience severe reading deficits such as oral reading and reading comprehension deficits. However, it is not known whether different types of lexical or sub-lexical components in reading are also impaired. In order to address this issue, the present study had 22 young Chinese patients with schizophrenia and 22 young Chinese normal controls undergo a battery of reading tests, which specifically measures lexical and sub-lexical components of reading in Chinese. The schizophrenic group further underwent Brief Psychiatric Rating Scale (BPRS) in order to ascertain the severity of patients' clinical symptoms. The results showed that compared to the controls, (1) the schizophrenic patients performed significantly poorly in orthographic processing, orthography-phonology mapping, and orthography-semantic mapping tests and further that (2) their performances in orthographic processing, and orthography-semantic mapping skill tests negatively correlated with the BPRS score. Note however that their ability to access their mental lexicon was intact. There is thus a clear need for studies with a larger sample-size and neurobiological measures which would lead to our better understanding of the behavioral as well as the neural relationships between schizophrenic patients, and their reading processing impairments, thus developing effective reading intervention programs for the schizophrenic patients.

Reduced prefrontal activation during a verbal fluency task in Chinese-speaking patients with schizophrenia as measured by near-infrared spectroscopy

Near-infrared spectroscopy (NIRS) has been applied to examine the possible functional alternations during the performance of cognitive tasks in schizophrenia. With this technique, previous studies have observed that patients with schizophrenia are often associated with reduced brain activation in the prefrontal cortex during the verbal fluency task (VFT) of the English version or the Japanese version. However, it remains unclear whether there is a brain functional impairment in Chinese-speaking patients with schizophrenia. In this study, we designed a Chinese version of the VFT and performed a multichannel NIRS study in a large group of patients with schizophrenia and healthy controls. We investigated brain activation during the task period of the Chinese version of the VFT within a schizophrenia group and a healthy group, respectively, and compared the relative changes between the two groups. Our results confirmed that Chinese-speaking patients with schizophrenia had significantly lower brain activation in the prefrontal cortex and superior temporal cortex when compared with healthy controls. Such findings based on the NIRS data provided us reliable evidences about brain functional deficits in the Chinese-speaking patients with schizophrenia.

Near-infrared spectroscopy for examination of prefrontal activation during cognitive tasks in patients with major depressive disorder: a meta-analysis of observational studies

AIMS

Near-infrared spectroscopy has the potential for aiding the diagnosis of major depressive disorder. The purpose of this study was to systematically review the evidence from observational studies regarding the use of near-infrared spectroscopy in patients with major depressive disorder and to identify the characteristic pattern of prefrontal lobe activity in major depressive disorder.

METHODS

medline, PubMed, Cochrane Library and Web of Science databases were searched in December 2013. All case-control studies were included. The quality of evidence was examined using the Newcastle-Ottawa Quality Assessment Scale. The primary outcome measures were the mean oxygenated and deoxygenated hemoglobin alterations of the cerebral cortex during cognitive activation periods. The standard mean difference for the overall pooled effects across the included studies was estimated using random or fixed effect models. The primary outcome measures were included in the meta-analysis.

RESULTS

Fourteen studies met the inclusion criteria. Six studies (n = 692 participants) were included in the analysis of the mean oxygenated hemoglobin alterations; the pooled mean standardized difference was -0.74 (95% confidence interval, -0.97 to -0.52), indicating that patients with major depressive disorder were associated with attenuated increase in oxygenated hemoglobin during cognitive activation in the prefrontal regions compared to healthy controls. Five studies (n = 668 participants) were included in the analysis of mean deoxygenated-hemoglobin changes; the pooled standardized mean difference was 0.18 (95% confidence interval, -0.20 to 0.56).

CONCLUSIONS

Using near-infrared spectroscopy measurements, we observed that compared to healthy subjects, patients with major depressive disorder had significantly lower prefrontal activation during cognitive tasks.

A case of pulmonary infiltrates in a patient with colon carcinoma

A 31-year-old white male with a known history of colon carcinoma was referred to the Interventional Pulmonary service for right lower lobe infiltrates and mucous plugging on computed tomography with concern for pneumonia. Bronchoscopy was performed revealing a broad based mass completely obstructing the bronchus intermedius. It was possible to pass a probe into the right lower lobe, and subsequent photoablation and mechanical debulking revealed that the mass was arising near the origin of the superior basal segment of the right lower lobe (RB6) and could be resected. Pathology confirmed this was consistent with the patient's known primary colon carcinoma. The potential for endobronchial metastasis in patients with colorectal carcinoma should be investigated in those patients with new or worsening pulmonary symptoms and signs.

Atorvastatin suppresses Toll-like receptor 4 expression and NF-κB activation in rabbit atherosclerotic plaques

BACKGROUND

Toll-like receptor 4 (TLR4) plays an essential role in the pathogenesis and progression of atherosclerosis, which overexpresses in atherosclerotic lesions and mediates the production of inflammatory factors. The aim of this study was to investigate the effects of atorvastatin on TLR4 protein and mRNA expression and its downstream factor NF-κB activation in rabbit atherosclerotic plaques.

MATERIALS AND METHODS

Rabbits continuously fed with high-fat diet for 24 weeks were randomly divided into two groups, the drug-treated group orally administrated with atorvastatin (2 mg/kg/day) three weeks after high-fat diet feeding and the model group with no treatment. The expression of TLR4 protein and mRNA, the level of activated NF-κB (p65) were respectively detected by western blotting, quantitative RT-PCR, and ELISA.

RESULTS

The results showed that atorvastatin treatment reduced the expression of TLR4 protein and mRNA by 24.1% (p < 0.05) and 46.9% (p < 0.01), respectively, and also inhibited NF-κB activation by 76.0% (p < 0.001) in the atherosclerotic plaques.

CONCLUSIONS

Thus, it was suggested that atorvastatin could exert an anti-atherosclerotic activity besides inhibiting cholesterol biosynthesis.

Role of pancreatic β-cell death and inflammation in diabetes

Apoptosis of pancreatic β-cells is the final step in the development of type 1 diabetes (T1D), leading to critically diminished β-cell mass and contributing to the onset of hyperglycaemia. The spontaneous apoptosis of pancreatic β-cells during pancreas ontogeny also induces cell death-associated inflammation, stimulates antigen-presenting cells and sensitizes naïve diabetogenic T cells. The role of pancreatic β-cell death in type 2 diabetes (T2D) is less clear. In the preclinical period of T2D, hyperinsulinaemia and β-cell hyperplasia develop to compensate for insulin resistance, which is clearly seen in animal models of T2D. For the development of overt T2D, relative insulin deficiency is critical in addition to insulin resistance. Insulin deficiency could be due to β-cell dysfunction and/or decreased β-cell mass. Pancreatic β-cell apoptosis due to lipid injury (lipoapoptosis), endoplasmic reticulum (ER) stress or JNK activation could contribute to the decreased β-cell mass in T2D. Activation of inflammasomes by lipid injury, ER stress, human islet amyloid polypeptide, hyperglycaemia or autophagy insufficiency could also lead to β-cell death or dysfunction. Thus, β-cell death and cell death-associated inflammation through innate immune receptors could be important in both T1D and T2D.

Frustrated tunnel ionization of noble gas dimers with Rydberg-electron shakeoff by electron charge oscillation

Strong field single ionization of homo- and heteronuclear noble gas dimers with ultrashort infrared laser pulses is experimentally investigated. A pronounced photoelectron yield maximum is found for dimers in the momentum range |p|≤0.1  a.u. which is absent for the corresponding monomer. This yield enhancement can be attributed to a new two-step strong field ionization mechanism active only in the dimers. In the first step, frustrated tunnel ionization at one of the atomic centers populates Rydberg states, which then become ionized in a second step through charge oscillation within the dimer ion core.

The significance of fragile histidine triad protein as a molecular prognostic marker of bladder urothelial carcinoma

OBJECTIVES

The role and clinical significance of fragile histidine triad (FHIT) gene in the pathogenesis of bladder urothelial carcinoma (UC) and the potential of Fhit protein as a prognostic biomarker for UC were investigated.

METHODS

FHIT expression was determined according to semiquantitative immunohistochemical staining for Fhit protein levels in normal bladder and bladder UC tissues. Associations between FHIT expression, clinicopathological features and survival were evaluated.

RESULTS

This study evaluated 42 cases of normal bladder and 125 cases of bladder UC; bladder UC cases had a median follow-up of 53.5 months. Immuno histochemistry showed that 95.2% of normal cases and 47.2% of bladder UC cases, respectively, were positive for Fhit protein; this difference was statistically significant. There was a significant association between negative FHIT expression in bladder UC and advanced tumour stage, high pathological grade, large tumour size, tumour recurrence and reduced survival time, but no association with age, gender, tumour number or tumour shape.

CONCLUSIONS

The FHIT gene may have an important role in the pathogenesis of bladder UC and was expressed at lower levels in bladder UC compared with normal bladder tissue. Using Fhit protein as a biomarker could provide important information about patient prognosis.

Autophagy deficiency in beta cells leads to compromised unfolded protein response and progression from obesity to diabetes in mice

AIMS/HYPOTHESIS

The unfolded protein response (UPR) in endoplasmic reticulum (ER) and autophagy are known to be related. We investigated the role of autophagy in UPR of pancreatic beta cells and the susceptibility of autophagy-deficient beta cells to the ER stress that is implicated in the development of diabetes.

METHODS

Rat insulin promoter (RIP)-Cre(+);autophagy-related 7 (Atg7)(F/W) mice were bred with ob/w mice to derive RIP-Cre(+);Atg7(F/F)-ob/ob mice and to induce ER stress in vivo. GFP-LC3(+)-ob/ob mice were generated to examine in vivo autophagic activity. Real-time RT-PCR was performed to study the expression of the genes of the UPR machinery. Proteolysis was assessed by determining release of incorporated radioactive leucine.

RESULTS

Production of UPR machinery was reduced in autophagy-deficient beta cells, which was associated with diminished production of p85α and p85β regulatory subunits of phosphoinositide 3-kinase. Because of compromised UPR machinery, autophagy-deficient beta cells were susceptible to ER stressors in vitro. When mice with beta cell-specific autophagy deficiency, which have mild hyperglycaemia, were bred with ob/ob mice to induce ER stress in vivo, severe diabetes developed, which was accompanied by an increase in beta cell death and accumulation of reactive oxygen species. The increased demand for UPR present in obesity was unmet in autophagy-deficient beta cells. Autophagy level and autophagic activity were enhanced by lipid, while proteolysis was reduced.

CONCLUSIONS/INTERPRETATION

These results suggest that autophagy is important for intact UPR machinery and appropriate UPR in response to lipid injury that increases demand for UPR. Autophagy deficiency in pancreatic beta cells may contribute to the progression from obesity to diabetes.

Structure effects in angle-resolved high-order above-threshold ionization of molecules

We present energy-resolved angular distributions of photoelectrons generated in above-threshold ionization (ATI) of nonaligned diatomic molecules N2 and O2 in high-intensity short laser pulses, with emphasis on the most energetic part of the spectra. The angular distribution for photoelectrons with energy of 10U(p) (U(p): ponderomotive energy), i.e., the plateau cutoff in ATI spectra, is found to be broader in O2 than in N2. Resorting to the analyses from both an S-matrix theory and an intuitive semiclassical model, we attribute the observation to the effect of the ground state molecular orbital structure on high-energy electron emission in strong-field molecular ionization.

Classical aspects in above-threshold ionization with a midinfrared strong laser field

We present high resolution photoelectron energy spectra of noble gas atoms from high intensity above-threshold ionization (ATI) at midinfrared wavelengths. An unexpected structure at the very low-energy portion of the spectra, in striking contrast to the prediction of the simple-man theory, has been revealed. A semiclassical model calculation is able to reproduce the experimental feature and suggests the prominent role of the Coulomb interaction of the outgoing electron with the parent ion in producing the peculiar structure in long wavelength ATI spectra.

Polymorphism of the regulatory region of the presenilin-2 gene in sporadic Alzheimer's disease: a case-control study

OBJECTIVE

presenilin-2 is one of the causative genes for familial Alzheimer's disease, and the apolipoprotein E epsilon4 allele is a major genetic risk factor for late-onset and sporadic early-onset Alzheimer's disease. Polymorphism of the regulatory region of presenilin-2 has recently been reported to be associated with sporadic Alzheimer's disease in a Russian population. The purpose of this study was to determine whether Alzheimer's disease is associated with the presenilin-2 gene polymorphism and the apolipoprotein E genotype in an extended case-control study.

METHODS

We examined 230 patients with Alzheimer's disease, along with an equal number of age- and sex-matched controls from the same community, in a Japanese population by using a Chi-square test for homogeneity and a logistic regression analysis.

RESULTS

The presenilin-2 polymorphism frequencies were similar in early-onset Alzheimer's disease patients (0.17) and younger controls (0.15), and in late-onset Alzheimer's disease (0.20) and elderly controls (0.20). We found no evidence for an association between the presenilin-2 polymorphism and the apolipoprotein E epsilon4 allele.

CONCLUSIONS

Our results fail to support an association of presenilin-2 gene polymorphism with Alzheimer's disease. The discrepancy between our results and the results of the Russian study appear to be due to racial differences.

Neurogenesis, migration, and apoptosis in the vomeronasal epithelium of adult mice

The location of neurogenesis and the direction of migration of neurons in the adult mouse vomeronasal organ is controversial. Cell division occurs at the center, and particularly, at the edges of the epithelium. Newly generated cells at the center of the epithelium participate in neurogenesis, however, it is unknown to what extent dividing cells at the edges participate in growth, become apoptotic or mature into neurons. Premitotic cells were labeled with bromodeoxyuridine (BrdU) in adult mice and animals allowed to survive for different postinjection periods. The terminal deoxynucleotidyl transferase-mediated biotinylated dUTP nick end-labeling (TUNEL) method was used to show the distribution of apoptotic cells. The vertical and horizontal position of BrdU-labeled cells was analyzed as a function of postinjection survival time. Vertical and horizontal migration of BrdU-labeled cells were detected. Cells in the central portions of the epithelium migrated vertically to become neurons as demonstrated by co-expression of olfactory marker protein. Cells at the edges migrated horizontally very slowly (less than 10% of the distance from the edge to the center of the epithelium per month), thus indicating that these cells participate in cell renewal exclusively in marginal regions. Neural turnover in the mouse vomeronasal epithelium, therefore appears to occur through a process of vertical migration. Data on the distribution of apoptotic cells indicate that a number of dividing cells throughout the epithelium, but particularly at the edges, die before becoming functional neurons. Accordingly, most dividing cells at the edges probably constitute a reservoir of stem cells dying before differentiation.

Passage of Harderian gland secretions to the vomeronasal organ of Thamnophis sirtalis (Serpentes: Colubridae)

The Harderian gland is a poorly understood structure found in the anterior orbit of most terrestrial vertebrates. In colubrid snakes it is a seromucous gland with a large postorbital portion. Numerous functions have been ascribed to this gland, including contributions to orbital lubrication or the vomeronasal system. Anatomically the Harderian gland is connected to the vomeronasal organ (VNO) via the nasolacrimal duct. In this study we traced the serous secretions of the Harderian gland of two subspecies of Thamnophis sirtalis (Colubridae), using autoradiographic techniques at the light-microscopic level. We injected the Harderian gland of the snakes with H3-proline either unilaterally (right side) or bilaterally. The right Harderian glands of both treatment groups were then injected with a potassium-rich solution. No labeling was observed in the orbital space of any treatment group, suggesting that the Harderian gland secretions of T. sirtalis do not function in orbital lubrication. Labeling was only observed in the right Harderian gland, Harderian gland ducts, nasolacrimal duct, apical vomeronasal sensory epithelium, VNO lumen, and vomeronasal duct. No such labeling was observed in any of the other treatments examined. Thus, the serous secretions of the Harderian gland in snakes flow to the VNO, and may be considered part of the vomeronasal system. The specific function of the Harderian gland secretions in the vomeronasal system remains to be determined.

Fetal mitochondrial heart and skeletal muscle damage in Erythrocebus patas monkeys exposed in utero to 3'-azido-3'-deoxythymidine

3'-azido-3'-deoxythymidine (AZT) is given to pregnant women positive for the human immunodeficiency virus type 1 (HIV-1) to reduce maternal-fetal viral transmission. To explore fetal mitochondrial consequences of this exposure, pregnant Erythrocebus patas monkeys were given daily doses of 1.5 mg (21% of the human daily dose) and 6.0 mg (86% of the human daily dose) of AZT/kg body weight (bw), for the second half of gestation. At term, electron microscopy of fetal cardiac and skeletal muscle showed abnormal and disrupted sarcomeres with myofibrillar loss. Some abnormally shaped mitochondria with disrupted cristae were observed in skeletal muscle myocytes. Oxidative phosphorylation (OXPHOS) enzyme assays showed dose-dependent alterations. At the human-equivalent dose of AZT (6 mg of AZT/kg bw), there was an approximately 85% decrease in the specific activity of NADH dehydrogenase (complex I) and three- to sixfold increases in specific activities of succinate dehydrogenase (complex II) and cytochrome-c oxidase (complex IV). Furthermore, a dose-dependent depletion of mitochondrial DNA levels was observed in both tissues. The data demonstrate that transplacental AZT exposure causes cardiac and skeletal muscle mitochondrial myopathy in the patas monkey fetus.

An association between anxiety and neurocardiogenic syncope during head-up tilt table testing

To study the association between anxiety and neurocardiogenic syncope as determined by head-up tilt table testing (HUT) in men and women with presyncope or syncope, patients with unexplained syncope or presyncope undergoing HUT were asked to complete the Burns Anxiety Inventory (BAI), a validated inventory of 33 questions with responses graded from 0 to 3. HUT consisted of a 30-minute tilt to 60 degrees, which if negative, was repeated with an isoproterenol infusion. A positive HUT was defined as symptomatic hypotension and/or bradycardia. Of the 66 patients who completed the BAI and underwent HUT, 33 were men and 33 were women. The mean age was 57 +/- 18 years (17-91 years). Patients with a positive HUT had a higher BAI score than those with a negative HUT (22 +/- 12 vs 14 +/- 13, P = 0.017). This association was stronger in women with a BAI score of 24 +/- 11 in those with a positive HUT versus 13 +/- 8 in those with a negative HUT (P = 0.005). In contrast, the mean BAI score for men with a positive HUT was 19 +/- 13, as compared to 15 +/- 16 for a negative HUT (P = 0.5). In conclusion, the present study demonstrates a statistical association between anxiety (as determined by BAI) and HUT result. Gender-based analysis revealed a more statistically significant relationship between anxiety and HUT outcome for women as compared to men.

The effects of intrinsic sympathomimetic activity on beta-blocker efficacy for treatment of neurocardiogenic syncope

To compare the efficacy and side effects of beta-blockers with intrinsic sympathomimetic activity (ISA) to those without ISA, we retrospectively reviewed patients diagnosed with neurocardiogenic syncope (NCS) as determined by head-up tilt table testing. Four hundred and thirty-one patients (mean age of 57 +/- 25 years) underwent head-up tilt table testing for syncope of unknown etiology, of which 120 patients were diagnosed with NCS; 87 of these patients were treated with beta-blocker therapy. Only 56 patients could be contacted during follow-up. Twenty-eight patients were treated with beta-blockers with ISA (acebutolol or pindolol) and 28 received beta-blockers without ISA (atenolol or metoprolol) based on physician preference and followed for up to 2 years. During the follow-up period, beta-blockers with or without ISA had comparable clinical efficacy in suppressing recurrent syncope in patients with NCS. However, beta-blockers with ISA were better tolerated and caused less fatigue (32% side effects) as compared to those without ISA (50% side effects; p = 0.23). The benefits of beta-blockers with ISA were more pronounced in patients less than 60 years old (19% side effects with beta-blocker with ISA as compared to 85% side effects with beta-blocker without ISA; p = 0.0004). Beta-blockers without ISA appear to be better tolerated and caused less fatigue in patients 65 years old or greater (20%) than in patients less than 65 years old (85%; p = 0.0002).

[Digital subtraction angiography of cerebrum for diagnosis of cavernous sinus fistula and its intravascular treatment]

OBJECTIVE

To evaluate the diagnosis of digital subtraction angiography (DSA) of cerebral arteries and the intravascular treatment for carotid artery-cavernous sinus fistula (CCF) mainly manifesting as pulsating exophthalmos.

METHODS

Digital subtraction angiography (DSA) of cerebral arteries was carried out for 15 patients with pulsating exophthalmos. Of them, detectable balloon and tungsten filament microcoil were used for intravascular embolism treatment in 12 cases, and the 3 cases with CCF of the branch of external carotid artery were not treated.

RESULTS

Of the 15 cases, 12 were fallen in the CCF of high flow type of unilateral internal carotid artery, and 3 in the CCF of low flow type of unilateral external carotid artery. The symptoms and signs of intravascular embolism disappeared after treatment in 11 cases.

CONCLUSION

Cerebral artery DSA and intravascular therapy are the ideal methods for the diagnosis and treatment of CCF mainly manifesting as pulsating exophthalmos.

Efficient integration of a realistic two-dimensional cardiac tissue model by domain decomposition

The size of realistic cardiac tissue models has been limited by their high computational demands. In particular, the Luo-Rudy phase II membrane model, used to simulate a thin sheet of ventricular tissue with arrays of coupled ventricular myocytes, is usually limited to 100 x 100 arrays. We introduce a new numerical method based on domain decomposition and a priority queue integration scheme which reduces the computational cost by a factor of 3-17. In the standard algorithm all the nodes advance with the same time step delta t, whose size is limited by the time scale of activation. However, at any given time, many regions may be inactive and do not require the same small delta t and consequent extensive computations. Hence, adjusting delta t locally is a key factor in improving computational efficiency, since most of the computing time is spent calculating ionic currents. This paper proposes an efficient adaptive numerical scheme for integrating a two-dimensional (2-D) propagation model, by incorporating local adjustments of delta t. In this method, alternating direction Cooley-Dodge and Rush-Larsen methods were used for numerical integration. Between consecutive integrations over the whole domain using an implicit method, the model was spatially decomposed into many subdomains, and delta t adjusted locally. The Euler method was used for numerical integration in the subdomains. Local boundary values were determined from the boundary mesh elements of the neighboring subdomains using linear interpolation. Because delta t was defined locally, a priority queue was used to store and order next update times for each subdomain. The subdomain with the earliest update time was given the highest priority and advanced first. This new method yielded stable solutions with relative errors less than 1% and reduced computation time by a factor of 3-17 and will allow much larger (e.g., 500 x 500) models based on realistic membrane kinetics and realistic dimensions to simulate reentry, triggered activity, and their interactions.

Active compression cardioversion for refractory atrial fibrillation

Application of manual pressure over standard external skin patches during cardioversion of atrial fibrillation (active compression cardioversion technique) may reduce transthoracic impedance, resulting in improvement in the overall cardioversion success rate.

Nonlinear dynamics in ventricular fibrillation

Electrogram recordings of ventricular fibrillation appear complex and possibly chaotic. However, sequences of beat-to-beat intervals obtained from these recordings are generally short, making it difficult to explicitly demonstrate nonlinear dynamics. Motivated by the work of Sugihara on atmospheric dynamics and the Durbin-Watson test for nonlinearity, we introduce a new statistical test that recovers significant dynamical patterns from smoothed lag plots. This test is used to show highly significant nonlinear dynamics in a stable canine model of ventricular fibrillation.

Antiemetic therapy in managed care oncology: roundtable discussion

Few diagnoses are feared more by patients than cancer. In addition to the life-threatening nature of many cancers, the spectre of very difficult the treatment provides patients with little or no level of comfort. However, recent advances in the treatment of the side effects of cancer chemotherapy are helping to change these attitudes. On April 4, 1996, a panel of experts was convened to discuss these issues and how they affect MCOs.

Transforming growth factor beta 1 suppresses genomic instability independent of a G1 arrest, p53, and Rb

Alterations in expression of or responsiveness to transforming growth factor beta (TGF-beta) are frequently found in human and animal epithelial cancers and are though to be important for loss of growth control in the neoplastic cell. We show here that keratinocyte cell lines from mice with a targeted deletion of the TGF-beta 1 gene have significantly increased frequencies of gene amplification in response to the drug N-phosphonoacetyl-L-aspartate (PALA) compared to TGF-beta 1-expressing control keratinocyte cell lines. In contrast to the control lines, the PALA-mediated G1 arrest did not occur in the TGF-beta 1 null keratinocytes despite the presence of wild-type p53 in both genotypes. Exogenous TGF-beta 1 suppresses gene amplification in the null keratinocytes at concentrations that do not cause a G1 growth arrest and in human tumor cell lines that are insensitive to TGF-beta 1-mediated growth inhibition. The pathway of TGF-beta 1 suppression is independent of the p53 and Rb genes, but requires an intact TGF-beta type II receptor. These studies reveal a novel TGF-beta-mediated pathway regulating genomic stability and suggest that defects in TGF-beta signaling may have profound effects on tumor progression independent of cell proliferation.

Development of an interactive computer-guided method for radiofrequency catheter ablation of ventricular tachycardia

The purpose of this study was to develop a simple computer-guided approach to localizing ventricular tachycardias during ventricular mapping. Six patients with sustained monomorphic ventricular tachycardia were connected to a 32-lead computer body surface mapping system. Isoarea maps of induced ventricular tachycardia were recorded. Then a pacing probe was placed in either the right or left ventricle, and maps were generated from a variety of sites. Differences between ventricular tachycardia and pace map maxima X, Y coordinates were utilized to guide catheter manipulation and localization. In 6 of 6 patients (100%) this method appeared to provide a systematic approach to ventricular tachycardia localization. Computer-generated correlations as well as the X, Y coordinates of the QRS isoarea maxima were used to determine proximity to the ventricular tachycardia foci and direct catheter manipulation. In the next three patients this method was applied prospectively to help guide catheter manipulation during ventricular tachycardia (two right ventricular outflow tract tachycardias, and one left ventricular tachycardia). After a mean of 4.0 +/- 1.7 radiofrequency applications, ventricular tachycardia was no longer inducible, and at 7 +/- 0 months follow-up there have been no arrhythmia recurrences. We conclude that online computerized body surface mapping can assist in localizing ventricular tachycardia. Differences in maxima during pace maps and in-situ ventricular tachycardias can help with catheter manipulation as well as with more precise identification of focal tachycardias. This technique appears to hold the promise of a simple computer-guided method that may facilitate radiofrequency catheter ablation.