Chronic nicotine exposure is associated with electrophysiological and sympathetic remodeling in the intact rabbit heart

Nicotine is the primary addictive component of tobacco products. Through its actions on the heart and autonomic nervous system, nicotine exposure is associated with electrophysiological changes and increased arrhythmia susceptibility. To assess the underlying mechanisms, we treated rabbits with transdermal nicotine (NIC, 21 mg/day) or control (CT) patches for 28 days before performing dual optical mapping of transmembrane potential (RH237) and intracellular Ca2+ (Rhod-2 AM) in isolated hearts with intact sympathetic innervation. Sympathetic nerve stimulation (SNS) was performed at the first to third thoracic vertebrae, and β-adrenergic responsiveness was additionally evaluated following norepinephrine (NE) perfusion. Baseline ex vivo heart rate (HR) and SNS stimulation threshold were higher in NIC versus CT (P = 0.004 and P = 0.003, respectively). Action potential duration alternans emerged at longer pacing cycle lengths (PCL) in NIC versus CT at baseline (P = 0.002) and during SNS (P = 0.0003), with similar results obtained for Ca2+ transient alternans. SNS shortened the PCL at which alternans emerged in CT but not in NIC hearts. NIC-exposed hearts tended to have slower and reduced HR responses to NE perfusion, but ventricular responses to NE were comparable between groups. Although fibrosis was unaltered, NIC hearts had lower sympathetic nerve density (P = 0.03) but no difference in NE content versus CT. These results suggest both sympathetic hypoinnervation of the myocardium and regional differences in β-adrenergic responsiveness with NIC. This autonomic remodeling may contribute to the increased risk of arrhythmias associated with nicotine exposure, which may be further exacerbated with long-term use.NEW & NOTEWORTHY Here, we show that chronic nicotine exposure was associated with increased heart rate, increased susceptibility to alternans, and reduced sympathetic electrophysiological responses in the intact rabbit heart. We suggest that this was due to sympathetic hypoinnervation of the myocardium and diminished β-adrenergic responsiveness of the sinoatrial node following nicotine treatment. Though these differences did not result in increased arrhythmia propensity in our study, we hypothesize that prolonged nicotine exposure may exacerbate this proarrhythmic remodeling.

Chronic nicotine exposure is associated with electrophysiological and sympathetic remodeling in the intact rabbit heart

Nicotine is the primary addictive component in tobacco products. Through its actions on the heart and autonomic nervous system, nicotine exposure is associated with electrophysiological changes and increased arrhythmia susceptibility. However, the underlying mechanisms are unclear. To address this, we treated rabbits with transdermal nicotine (NIC, 21 mg/day) or control (CT) patches for 28 days prior to performing dual optical mapping of transmembrane potential (RH237) and intracellular Ca 2+ (Rhod-2 AM) in isolated hearts with intact sympathetic innervation. Sympathetic nerve stimulation (SNS) was performed at the 1 st - 3 rd thoracic vertebrae, and β-adrenergic responsiveness was additionally evaluated as changes in heart rate (HR) following norepinephrine (NE) perfusion. Baseline ex vivo HR and SNS stimulation threshold were increased in NIC vs. CT ( P = 0.004 and P = 0.003 respectively). Action potential duration alternans emerged at longer pacing cycle lengths (PCL) in NIC vs. CT at baseline ( P = 0.002) and during SNS ( P = 0.0003), with similar results obtained for Ca 2+ transient alternans. SNS reduced the PCL at which alternans emerged in CT but not NIC hearts. NIC exposed hearts also tended to have slower and reduced HR responses to NE perfusion. While fibrosis was unaltered, NIC hearts had lower sympathetic nerve density ( P = 0.03) but no difference in NE content vs. CT. These results suggest both sympathetic hypo-innervation of the myocardium and diminished β-adrenergic responsiveness with NIC. This autonomic remodeling may underlie the increased risk of arrhythmias associated with nicotine exposure, which may be further exacerbated with continued long-term usage.

NEW & NOTEWORTHY

Here we show that chronic nicotine exposure was associated with increased heart rate, lower threshold for alternans and reduced sympathetic electrophysiological responses in the intact rabbit heart. We suggest that this was due to the sympathetic hypo-innervation of the myocardium and diminished β- adrenergic responsiveness observed following nicotine treatment. Though these differences did not result in increased arrhythmia propensity in our study, we hypothesize that prolonged nicotine exposure may exacerbate this pro-arrhythmic remodeling.

Mapping the Anatomical Distribution of MRI-Identified Locoregional Recurrence following Robotic-Assisted Laparoscopic Prostatectomy for Prostate Adenocarcinoma

PURPOSE/OBJECTIVE(S)

The pattern of locoregional recurrence specifically after robotic-assisted laparoscopic prostatectomy (RALP) for prostate adenocarcinoma is still unknown. In this study, we reviewed pelvic magnetic resonance images (MRI) after postoperative biochemical recurrence (BCR) and drew a map of locoregional recurrence to support evidence of determining the optimal target volume of salvage radiotherapy in a post-RALP BCR scenario.

MATERIALS/METHODS

We have retrospectively searched 7,583 prostate adenocarcinoma patients who have received RALP in our institution between January 2010 and December 2021, and found a pool of highly selected patients with gross tumor recurrence confirmed by post-BCR pelvic MRIs and did not have other histories of malignancy. BCR was defined as the serum PSA more or equal to 0.2 ng/mL, or three consecutive increases. Patients with serum PSA nadir more or equal to 0.2 ng/mL on the 90th postoperative day (POD 90) were excluded to guarantee successful tumor removal. We have reviewed serum PSA levels using R codes, MRI and pathological reports using Excel, and descriptive statistics using SPSS 25. The gross lesions were contoured on the correlating MRIs using MIM Maestro 7.1. The RT structure DICOM files were merged into a map using MATLAB 2022b. In addition, we have conducted Fisher exacted test, Mann-Whitney U test, and logistic regression to identify risk factors for regional recurrence.

RESULTS

A total of 173 patients were identified with locoregional recurrence from post-BCR pelvic MRIs, and 139 (80.3%) patients were in the high-risk group or very-high-risk group according to the NCCN guidelines: 57 (32.9%) patients with histological grade group 5, 50 (28.9%) patients with initial PSA over 20 ng/mL, 114 (65.9%) patients with extracapsular extension, 55 (31.8%) patients with seminal vesicle invasion, and 15 (9%) patients with pN1. The median follow-up was 4.7 (IQR 2.8-6.9) years for pelvic MRIs and 5.8 (IQR 4.0-8.6) years for serum PSA. The BCF survival was median of 10.7 (IQR 4.6-19.1) months, and the locoregional recurrence-free survival was median of 24.6 (IQR 9.7-49.4) months for this subgroup of patients. At first locoregional recurrence, 148 (85.5%) patients were local only, 20 (11.6%) patients were regional only, and 5 (2.9%) patients were both local and regional. Out of the 25 patients with regional recurrence, the incidence of gross tumor recurrence differed by nodal sites: 3 (12%) in perirectal space, 5 (20%) in internal iliac, 7 (28%) in obturator, 13 (52%) in external iliac, and 6 (24%) in common iliac lymph nodes.

CONCLUSION

We have found 173 patients and were able to map reliable gross tumor recurrence sites after RALP and confirmed by pelvic MRIs following BCR. The map supports evidence of using the existing consensus pelvic clinical target volume of salvage radiotherapy, in a post-RALP BCR scenario.

Comparison of Early Outcomes of Stereotactic Accelerated Partial Breast Irradiation vs. Volumetric Modulated Arc Therapy-Based FAST-FORWARD Whole Breast Irradiation for Breast Cancer

PURPOSE/OBJECTIVE(S)

Despite evidence supporting APBI from 8 published prospective randomized trials enrolling over 10,000 women, the uptake of APBI in clinical practice is surprisingly low. This is being exacerbated by a new, convenient, and safe shortened WBI schedule. Here, we report the dosimetric and early outcome analyses of the first >1000 patients treated at our institution since the first adoption of stereotactic APBI and the ultra-hypofractionated WBI regimen.

MATERIALS/METHODS

From 2016 to 2022, 801 women with breast cancers in the suitable or cautionary categories according to the ASTRO APBI consensus panel guidelines, received 30 Gy in 5 fractions (92%) either using a robotic stereotactic radiation system (83%) or stereotactic volumetric-based arc therapy (VMAT, 17%). Between 2020 and 2022, 468 women, who were not candidates for APBI and not undergoing any regional irradiation received 26 Gy in 5 fractions using VMAT to the whole breast with the addition of cardiac sparing technique in left-sided breast cancer patients. Tumor bed boosts were delivered in 99% of FF-WBI patients. We evaluated dose-volume histogram parameters for target volumes and organs-at-risk and radiation-related toxicities during RT or within 6 months after the end of RT.

RESULTS

Target volume coverage was acceptable in both groups, with mean 96% of the target volumes receiving 95% of the prescribed doses and 0 cm3 within target volumes exceeding 105% of the prescribed doses. S-APBI resulted in small, but statistically significant, reductions in the radiation dose delivered to the ipsilateral breast, contralateral breast, lungs, heart, and coronary artery compared with FF-WBI. Comparing WBI to APBI, the mean contralateral breast dose, ipsilateral lung V20 Gy, mean contralateral lung dose, and mean heart dose, were reduced by 89%, 78%, 73%, and 29%, respectively. With median follow-up periods of 32 months for s-APBI and 19 months for FF-WBI, acute toxicity was assessable in all patients. The risks of any grade acute toxicity were 21% for s-APBI and 25% for FF-WBI (p = .117). Among them, grade 2 rates were 1.3% in both groups and no severe toxicity has been reported.

CONCLUSION

We found s-APBI and VMAT-based FF WBI were associated with favorable dosimetric and acute toxicity profiles. However, considering significantly less irradiated volume in the breast, lungs, and heart, APBI with advanced available technique options should be considered over any WBI-based approach for patients at low risk for local recurrence.

Beneficial Role of Multi-Disciplinary Treatment for Anaplastic Thyroid Cancer with Initial Distant Metastasis

PURPOSE/OBJECTIVE(S)

Anaplastic thyroid cancer (ATC) is a rare, highly aggressive tumor, with median survival around 5 months. Approximately half of the ATC patients presents with distant metastases at diagnosis, showing even more devastating prognosis, yet no outcome analysis had been reported. In this study, we aim to evaluate the clinical outcome of M1 ATC patients, and to define the group of patients who would benefit from local treatment based on multi-disciplinary approach.

MATERIALS/METHODS

A total of 133 histology-confirmed ATC patients underwent protocol-based multidisciplinary treatment including surgery and chemoradiotherapy (CRT) between May 2016 and January 2022. Patients received intensity-modulated radiotherapy of 30 fractions concurrently with paclitaxel on days 1, 8 and 15 every 4 weeks, and lenvatinib was added upon progression. After 18 fractions of CRT, interim response analysis using modified RECIST was conducted for adaptive treatment planning. We reviewed 58 patients with distant metastasis at diagnosis (stage IVC). Overall survival (OS) and progression-free survival (PFS) were measured from the day of diagnosis.

RESULTS

Most common metastatic site was lung (91.4%), followed by bone (31.0%) and brain (5.2%). Lenvatinib was added for 35 patients after any sign of progression. Fourteen patients received upfront surgery (16 debulking and 5 total) followed by adjuvant CRT in 16 patients. Thirty-one patients received upfront CRT with 2 patients receiving total resection after sufficient down-staging. Six (10%) patients could not complete radiotherapy but continued receiving systemic treatment. The median follow-up was 5.9 months. The median and 1-year OS were 6.2 months and 20.5%, and PFS were 3.7 months and 3.5%. Total RT dose over 60 Gy significantly improved median OS (7.5 vs 4.1 months, p = 0.012) and median PFS (4.4 vs 3.0, p = 0.010). Patients with less than 10 initial metastatic tumors showed better median OS (9.1 vs 4.6 months, p = 0.002) but not PFS (5.1 vs 3.6, p = 0.485). At interim analysis, early response (CR, PR and SD) of primary tumor was not associated with survival, while progression of distant metastases showed significantly worse median OS (9.8 vs 4.6 months, p = 0.001). More than 10 metastatic tumors (HR 2.73, 95% CI 1.32-5.66) and stable metastasis at interim analysis (HR 2.39, 95% CI 1.04-5.48) remained as significant factor in the multivariable cox regression analysis. Median OS and PFS of patients with less than 10 metastases showing no progression at interim analysis were 9.1 months, and 5.1 months.

CONCLUSION

Local treatment combined with chemotherapy for M1 ATC patients showed outcome comparable to those of non-metastatic ATC results. Active local treatment should be considered especially for patients with less than 10 metastases, and patients without distant progression in early response evaluation.

Assessment of diagnostic accuracy and complication rates of CT-guided percutaneous core-needle biopsy for lung lesion: difference between solid and sub-solid nodules based on propensity score matching analysis

AIM

To compare the success and complication rates of computed tomography (CT)-guided percutaneous core-needle biopsy (PCNB) based on the density of lung nodules, using propensity score matching (PSM).

MATERIALS AND METHODS

This single-centre retrospective study included 1,312 PCNB cases of lung lesions, including solid (n=1,120), part-solid (n=115), and non-solid nodules (n=77), that were detected between March 2013 and March 2021. The diagnostic accuracy and complication rates of pneumothorax and pulmonary haemorrhage were analysed before PSM. To perform PSM, part-solid and non-solid nodules were combined and newly defined as sub-solid nodules. The diagnostic accuracy and complication rates of pneumothorax and pulmonary haemorrhage were then compared between solid and sub-solid nodules after PSM.

RESULTS

Among the 1,312 included cases, the success rate and incidence of pneumothorax after CT-guided PCNB for solid, part-solid, and non-solid nodules were not statistically different (p=0.080 and 0.410). However, the rates of overall pulmonary haemorrhage showed statistical differences (p<0.001), particularly between solid and part-solid nodules (p<0.001) and between solid and non-solid nodules (p<0.001). After PSM, the incidence rates of overall pulmonary haemorrhage in solid and sub-solid nodules were 8.9% (17/192) and 29.7% (44/182), respectively, showing a statistically significant difference (p<0.001).

CONCLUSION

There is increased risk of haemorrhage in CT-guided needle biopsy of sub-solid nodules compared to solid nodules. Increased emphasis should be placed on the risk of pulmonary haemorrhage when consenting these patients.

Whole-heart multiparametric optical imaging reveals sex-dependent heterogeneity in cAMP signaling and repolarization kinetics

Cyclic adenosine 3',5'-monophosphate (cAMP) is a key second messenger in cardiomyocytes responsible for transducing autonomic signals into downstream electrophysiological responses. Previous studies have shown intracellular heterogeneity and compartmentalization of cAMP signaling. However, whether cAMP signaling occurs heterogeneously throughout the intact heart and how this drives sex-dependent functional responses are unknown. Here, we developed and validated a novel cardiac-specific fluorescence resonance energy transfer-based cAMP reporter mouse and a combined voltage-cAMP whole-heart imaging system. We showed that in male hearts, cAMP was uniformly activated in response to pharmacological β-adrenergic stimulation. In contrast, female hearts showed that cAMP levels decayed faster in apical versus basal regions, which was associated with nonuniform action potential changes and notable changes in the direction of repolarization. Apical phosphodiesterase (PDE) activity was higher in female versus male hearts, and PDE inhibition prevented repolarization changes in female hearts. Thus, our imaging approach revealed sex-dependent regional breakdown of cAMP and associated electrophysiological differences.

Prior activation of social work team process by pre-admission one-click automatic referral system

Background

Coronary artery disease (CAD) is the leading global cause of mortality. Coronary angiography (CAG) is often performed for CAD patients, and the mean length of stay (LoS) is 4 d. Requests to the social work team (SWT) are often delayed until just before discharge, causing unnecessarily prolonged LoS and reduced chances of obtaining financial support. If the SWT’s support system is activated beforehand for scheduled CAGs, the LoS would be shorter and patients would be relieved of emotional and financial burdens.

Methods

Collaborating with the cardiology and medical informatics departments, a one-click automatic referral system (OARS) was set up (January-May 2021). When cardiologists scheduled a CAG in the outpatient department, an OARS cue popped automatically for the medical aid recipients. The cardiologists could also activate the pre-admission OARS for other patients when necessary. Subsequently, the SWT responded on that day to discuss initiating the financial support process with the candidates. The rate of cardiologists’ pre-admission referral to SWT, decision-making time on financial support provision, and proportion of patients receiving financial support were compared before and after initiating OARS.

Results

After initiating pre-admission OARS, the rate of cardiologists’ pre-admission referral to SWT increased from 17.8% (18/101: mean age, 64.6±12.0 y; 32 females; January-December 2020) to 59.1% (55/93: mean age, 64.0±11.8 y; 29 females; June-December 2021) (p &lt; 0.001). Although the decision-making time to provide financial support did not change significantly (8.4±11.1 vs. 4.7±11.6 d; p = 0.96), the proportion of patients receiving financial support increased (45.5% [46/101] vs. 60.2% [56/93]; p = 0.045).

Conclusions

By enhancing the cardiologists’ pre-admission referral to SWT and success rate of receiving financial support, the proactive strategy of pre-admission OARS benefits CAD patients scheduled for CAG.

Key messages

• By building a proactive referral strategy of pre-admission OARS, more CAD patients scheduled for CAG could obtain timely financial support and be relieved both emotionally and financially by the SWT.

• This pre-admission OARS might be incorporated for more disease entities for patients in need.

Role of Reduced Sarco-Endoplasmic Reticulum Ca2+-ATPase Function on Sarcoplasmic Reticulum Ca2+ Alternans in the Intact Rabbit Heart

Sarcoplasmic reticulum (SR) Ca²⁺ cycling is tightly regulated by ryanodine receptor (RyR) Ca²⁺ release and sarco-endoplasmic reticulum Ca²⁺-ATPase (SERCA) Ca²⁺ uptake during each excitation–contraction coupling cycle. We previously showed that RyR refractoriness plays a key role in the onset of SR Ca²⁺ alternans in the intact rabbit heart, which contributes to arrhythmogenic action potential duration (APD) alternans. Recent studies have also implicated impaired SERCA function, a key feature of heart failure, in cardiac alternans and arrhythmias. However, the relationship between reduced SERCA function and SR Ca²⁺ alternans is not well understood. Simultaneous optical mapping of transmembrane potential (V_m) and SR Ca²⁺ was performed in isolated rabbit hearts (n = 10) using the voltage-sensitive dye RH237 and the low-affinity Ca²⁺ indicator Fluo-5N-AM. Alternans was induced by rapid ventricular pacing. SERCA was inhibited with cyclopiazonic acid (CPA; 1–10 μM). SERCA inhibition (1, 5, and 10 μM of CPA) resulted in dose-dependent slowing of SR Ca²⁺ reuptake, with the time constant (tau) increasing from 70.8 ± 3.5 ms at baseline to 85.5 ± 6.6, 129.9 ± 20.7, and 271.3 ± 37.6 ms, respectively (p < 0.05 vs. baseline for all doses). At fast pacing frequencies, CPA significantly increased the magnitude of SR Ca²⁺ and APD alternans, most strongly at 10 μM (pacing cycle length = 220 ms: SR Ca²⁺ alternans magnitude: 57.1 ± 4.7 vs. 13.4 ± 8.9 AU; APD alternans magnitude 3.8 ± 1.9 vs. 0.2 ± 0.19 AU; p < 0.05 10 μM of CPA vs. baseline for both). SERCA inhibition also promoted the emergence of spatially discordant alternans. Notably, at all CPA doses, alternation of SR Ca²⁺ release occurred prior to alternation of diastolic SR Ca²⁺ load as pacing frequency increased. Simultaneous optical mapping of SR Ca²⁺ and V_m in the intact rabbit heart revealed that SERCA inhibition exacerbates pacing-induced SR Ca²⁺ and APD alternans magnitude, particularly at fast pacing frequencies. Importantly, SR Ca²⁺ release alternans always occurred before the onset of SR Ca²⁺ load alternans. These findings suggest that even in settings of diminished SERCA function, relative refractoriness of RyR Ca²⁺ release governs the onset of intracellular Ca²⁺ alternans.

Light triggering goldsomes enable local NO-generation and alleviate pathological vasoconstriction

While nitric oxide (NO) can remedy vasoconstriction, inhalation of NO may cause systematic toxicity. We report a goldsome, which comprises a hollowed poly(lactic-co-glycolic acid) (PLGA) polymersome with S-nitrosoglutathione (GSNO, a NO donor) molecules and gold nanoparticles (Au NPs) incorporated in its hydrophilic core and hydrophobic membrane, respectively. Photothermal heating caused breakdown of polymersomes and enabled NO generation through reaction between GSNO and Au NPs. Photo-illumination at the zebrafish head led to local NO generation and selective cerebral vasodilation while it had little effects in regions away from the illumination site, and effectively mitigated hypoxia induced cerebral vasoconstriction. We demonstrate a translational potential by showing photo-stimulated NO generation with a clinical intravascular optical catheter. In conclusion, the goldsome, which enables light stimulated local NO generation and can be delivered with clinical intravascular optical catheters, should extend applications of NO therapies while surmounting limitations associated with systemic administration.

Factors promoting nuclear envelope assembly independent of the canonical ESCRT pathway

The nuclear envelope (NE) undergoes dynamic remodeling to maintain NE integrity, a process involving the inner nuclear membrane protein LEM2 recruiting CHMP7/Cmp7 and then ESCRT-III. However, prior work has hinted at CHMP7/ESCRT-independent mechanisms. To identify such mechanisms, we studied NE assembly in Schizosaccharomyces japonicus, a fission yeast that undergoes partial mitotic NE breakdown and reassembly. S. japonicus cells lacking Cmp7 have compromised NE sealing after mitosis but are viable. A genetic screen identified mutations that promote NE integrity in cmp7Δ cells. Unexpectedly, loss of Lem2 or its interacting partner Nur1 suppressed cmp7Δ defects. In the absence of Cmp7, Lem2 formed aggregates that appear to interfere with ESCRT-independent NE sealing. A gain-of-function mutation implicated a membrane and ESCRT-III regulator, Alx1, in this alternate pathway. Additional results suggest a potentially general role for unsaturated fatty acids in NE integrity. These findings establish the existence of mechanisms for NE sealing independent of the canonical ESCRT pathway.

Factors affecting the dormancy and germination of bleeding heart [Lamprocapnos spectabilis (L.) Fukuhara] seeds

Information on the optimal conditions to promote the germination of Lamprocapnos spectabilis (L.) Fukuhara seeds is limited; consequently, this study was conducted to establish the requirements to break seed dormancy and promote germination. The selected seeds had morphophysiological dormancy and had not begun embryo development. To study the dormancy breaking and embryo development processes, seeds were subjected to constant or changing temperature treatments during moist stratification. High temperature and humidity resulted in vigorous embryo growth, with the longest embryos occurring after 1 month of incubation at 20 °C. At 4 °C, the seeds required incubation period of at least 3 months to germinate. Embryo growth and germination were higher with changing high and low temperatures than under a constant temperature, and changing temperatures also considerably changed the endogenous hormone levels, embryo development and germination. Bioactive gibberellin (GA) content was higher in seeds incubated at 20 °C for 1 month, then at 4 °C for 2 months. The content of endogenous abscisic acid in seeds subjected to the same treatment decreased by 97.6% compared with that of the untreated seeds. Embryo growth and seed germination require changing high and low temperatures; however, exogenous GA₃ could substitute for high temperatures, as it also causes accelerated germination. In this study, the seeds of L. spectabilis were identified as an intermediate simple type, a sub-level of morphophysiologically dormant seeds.

Efficacy and safety of transarterial chemoembolisation with cone-beam CT in patients with hepatocellular carcinoma within the Milan criteria: a retrospective cohort study

AIM

To compare the therapeutic efficacy and safety of transarterial chemoembolisation (TACE) for hepatocellular carcinoma (HCC) within the Milan criteria with or without the use of cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Patients with HCC within the Milan criteria who underwent conventional angiography-guided TACE (Angio-TACE group: 58 patients from January 2010 to December 2011) were compared with those who underwent CBCT-guided TACE (CBCT-TACE group: 55 patients from January 2013 to December 2014). Local progression-free survival (LPFS), progression-free survival (PFS), and overall survival (OS) were compared. Adverse events after TACE were also investigated.

RESULTS

Baseline characteristics were balanced between the two groups. LPFS was significantly longer in the CBCT-TACE group than in the Angio-TACE group (median: not reached for 36 versus 19.2 months, respectively; Log-rank p=0.029). In multivariable Cox regression analysis, CBCT guidance had a significantly lower risk of local progression or death (adjusted hazard ratio: 0.585; 95% confidence interval, 0.344-0.995; p=0.048); however, there was no significant difference in PFS (3-year PFS: 15.9% versus 26.8%, respectively; p=0.122) or OS (3-year OS: 85% versus 88.2%, respectively; p=0.761) between the Angio-TACE and CBCT-TACE groups. Post-embolisation syndrome occurred significantly less frequently in the CBCT-TACE group (p=0.002).

CONCLUSION

CBCT-guided TACE could improve local tumour control for HCC within Milan criteria and showed fewer cases of post-embolisation syndrome.

Abstract OT2-04-02: A phase 3 study of post-lumpectomy radiotherapy to whole breast + regional lymph nodes vs whole breast alone for patients with pN1 breast cancer treated with taxane-based chemotherapy (KROG 1701): Trial in progress

Background

In patients with early stage breast cancer, regional nodal irradiation (RNI) is added to whole breast irradiation (WBI) in order to control microscopic regional disease and to prevent systemic spread of cancer. According to recent randomized trials (MA.20 and EORTC 22922-10925), prophylactic RNI was associated with improvement in disease-free survival (DFS) in the patients with high-risk node negative or pN1 breast cancer. However, systemic agents now known to improve loco-regional control, such as taxane or endocrine therapy, were prescribed to a small percentage of patients in the studies. The benefit of RNI found in the previous studies might be attributed to incorporation of less effective systemic treatments. The impact of prophylactic RNI in pN1 breast cancer should be evaluated in the patients receiving modern systemic treatment. The current study was conducted to compare the effect of post-lumpectomy WBI vs WBI plus RNI on DFS in pN1 breast cancer patients who received adjuvant taxane-based chemotherapy.

Methods

This study is a multicenter, phase 3, randomized controlled non-inferiority trial (NCT03269981). Eligibility criteria are ≥ 20 years female; pathologically proven invasive carcinoma of the breast; one to three positive axillary lymph nodes (pN1) in pathologic specimen; receiving breast-conserving surgery followed by taxane-based chemotherapy; having adjuvant endocrine therapy or anti-HER2 treatment according to molecular subtype of tumor. Patients are randomly assigned in a 1:1 ratio to receive WBI or WBI plus RNI. Patient randomization was stratified by molecular subtype of tumor (i.e. luminal A/luminal B/luminal HER2/HER2-enriched/triple-negative) and methods of axillary management (i.e. sentinel lymph node biopsy/axillary lymph node dissection). The primary outcome is DFS. The secondary outcomes include DFS according to molecular subtype, treatment-related toxicity, and patient's quality of life per EORTC QLQ-C30 and QLQ-BR23. Patients will be followed for survival and disease recurrence for seven years. A total of 1,926 patients are planned to be enrolled, with recruitment initiated in April 2017. As of June 2018, a total of 236 patients were enrolled.

Acknowledgement

This study was supported by a grant from the National R&D Program for Cancer Control, Ministry of Health & Welfare, Republic of Korea (grant number: HA17C0043010018).

Citation Format: Kim H, Park W, Choi DH, Ahn SJ, Kim SS, Kim ES, Lee JH, Lee KC, Kim JH, Lee H-S, Kim JH, Kim MY, Park HJ, Kim K, Song SH, Kwon J, Lee IJ, Kim TH, Kim TG, Chang AR, Cho O, Jeong BK, Ha B, Lee J, Ki Y. A phase 3 study of post-lumpectomy radiotherapy to whole breast + regional lymph nodes vs whole breast alone for patients with pN1 breast cancer treated with taxane-based chemotherapy (KROG 1701): Trial in progress [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-04-02.

Abstract 123: Establishing a Zebrafish Model of Ischemic Stroke Induced by Photochemical Thrombosis: a Novel Platform for Translational Researches

Introduction: Ischemic stroke is a leading cause of death and disability worldwide. Animal models of stroke are important for translational researches. We herein developed a novel zebrafish model of ischemic stroke using selective photochemical thrombosis, based on which further pathophysiological studies and pharmacological screening can be done.

Method: Using 5 day post-fertilization zebrafish larva, we injected a photosensitizer rose bengal (120 pg) into the cardinal vein and employed a green laser (λ = 532 nm) targeting at selected cerebral arteries to induce photochemical thrombosis. The fluorescent FITC-dextran was used to stain the larval blood. The dynamic cerebral blood flow was continuously monitored. The neuronal death 12 h after arterial occlusion was indicated by acridine orange (AO). A neurological scoring system measuring the movement, coordination, and response to stimuli was established to determine the neurological function at 24 h. Thrombolysis using recombinant tissue plasminogen activator (rt-PA, 300 ng) at 0.5 and 3 h post-occlusion with comparison of the above parameters was used to demonstrate the potential application of this model.

Results: Photochemical thrombosis consistently induced occlusion of the selected cerebral arteries. Occlusion at the basilar artery led to high mortality (73.3% at 12 h). All zebrafish survived the occlusion at the 1 st branch of central artery (CtA), but showed significantly increased AO stain and worsened neurological scores than control. Early treatment of rt-PA at 0.5 h post-occlusion resulted in a higher re-canalization rate than that at 3 h (40.0 vs. 26.7%). Moreover, the early treatment group exhibited significantly lower AO stain (42.2 ± 9.4 vs. 102.6 ± 17.4 a.u., P < 0.05) and improved neurological scores (4.2 ± 0.8 vs. 2.7 ± 1.1, P < 0.05). In contrast, no significant improvement was shown in the delayed treatment group even if the occluded artery had been reopened.

Conclusion: This zebrafish model of ischemic stroke demonstrates characteristic pathophysiological responses and therapeutic effects seen in clinical stroke. With zebrafish being an increasingly employed model animal, there exist great potentials for this model to be applied in basic researches and translational studies.

Iodine insertion and dispersion of refractive index in organic single crystal semiconductor

Insertion of halogens such as bromine or iodine affects the electronic polarizability of ions and the local field inside the medium, and thus modifies the refractive index. Acquiring precise knowledge of the dispersion of refractive index and ultimately tailoring conventional semiconductors for wide-range refractive index control have been a vital issue to resolve before realizing advanced organic optoelectronic devices. In this report, dispersions of the refractive index of a single crystal tetramethyltetraselenafulvalene [C₁₀H₁₂Se₄] (TMTSF) are thoroughly studied from broadband interference modulations of photoluminescence (PL) spectra at various temperatures and doping levels. A large enhancement of the refractive index, more than 20% of the intrinsic value, is achieved with inclusion of a small composition of iodide ions, while the structural and optical properties remain mostly intact. Nearly temperature independent dispersion of the refractive index suggests that, unlike most polymers in which the thermal expansion coefficient dominates over the change of polarizability with temperature, the latter enhances significantly and may become more or less comparable to the thermal expansion coefficient given by 1.71 × 10⁻⁴/K, when single crystal TMTSF is doped by iodine.

Zebrafish model of photochemical thrombosis for translational research and thrombolytic screening in vivo

Acute thromboembolic diseases remain the major global cause of death or disability. Although an array of thrombolytic and antithrombotic drugs has been approved to treat or prevent thromboembolic diseases, many more drugs that target specific clotting mechanisms are under development. Here a novel zebrafish model of photochemical thrombosis is reported and its prospective application for the screening and preclinical testing of thrombolytic agents in vivo is demonstrated. Through photochemical excitation, a thrombus was induced to form at a selected section of the dorsal aorta of larval zebrafish, which had been injected with photosensitizers. Such photochemical thrombosis can be consistently controlled to occlude partially or completely the targeted blood vessel. Detailed mechanistic tests indicate that the zebrafish model of photochemical thrombosis exhibits essential features of classical coagulation and a thrombolytic pathway. For demonstration, tissue plasminogen activator (tPA), a clinically feasible thrombolytic agent, was shown to effectively dissolve photochemically induced blood clots. In light of the numerous unique advantages of zebrafish as a model organism, our approach is expected to benefit not only the development of novel thrombolytic and antithrombotic strategies but also the fundamental or translational research targeting hereditary thrombotic or coagulation disorders.

Controllable NO release from Cu1.6S nanoparticle decomposition of S-nitrosoglutathiones following photothermal disintegration of polymersomes to elicit cerebral vasodilatory activity

Since the discovery of nitric oxide (NO) as a vasodilator, numerous NO therapies have been attempted to remedy disorders related to pathological vasoconstriction such as coronary artery disease. Despite the advances, clinical applications of NO therapies remain limited mainly because of the low stability of molecular NO donors (and NO molecules), and concerns about the increased oxidative stress and reduced arterial pressure associated with the systemic administration of NO. Here we design a photo-responsive polymersome with nitrosothiols and Cu_1.6S nanoparticles in its core and shell, respectively, and demonstrate the photo-triggered release of NO and its vasodilatory activity on zebrafish. Unlike conventional approaches, our design enhances the stability of NO donors and prospectively enables spatiotemporal regulation of NO release, thus minimizing the harmful effects associated with conventional NO therapies. We anticipate that such a strategy will open up new clinical applications of NO and help reveal the complex biological effects of NO in vivo.

Roles of the novel coiled-coil protein Rng10 in septum formation during fission yeast cytokinesis

The regulation of Rho-GAP localization is not well understood. A novel coiled-coil protein Rng10 is characterized that localizes the Rho-GAP Rga7 in fission yeast. Rng10 and Rga7 physically interact and work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation during cytokinesis.

Rho GAPs are important regulators of Rho GTPases, which are involved in various steps of cytokinesis and other processes. However, regulation of Rho-GAP cellular localization and function is not fully understood. Here we report the characterization of a novel coiled-coil protein Rng10 and its relationship with the Rho-GAP Rga7 in fission yeast. Both rng10Δ and rga7Δ result in defective septum and cell lysis during cytokinesis. Rng10 and Rga7 colocalize on the plasma membrane at the cell tips during interphase and at the division site during cell division. Rng10 physically interacts with Rga7 in affinity purification and coimmunoprecipitation. Of interest, Rga7 localization is nearly abolished without Rng10. Moreover, Rng10 and Rga7 work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation in cytokinesis. Our results show that cellular localization and function of the Rho-GAP Rga7 are regulated by a novel protein, Rng10, during cytokinesis in fission yeast.

Roles of the TRAPP-II Complex and the Exocyst in Membrane Deposition during Fission Yeast Cytokinesis

The cleavage-furrow tip adjacent to the actomyosin contractile ring is believed to be the predominant site for plasma-membrane insertion through exocyst-tethered vesicles during cytokinesis. Here we found that most secretory vesicles are delivered by myosin-V on linear actin cables in fission yeast cytokinesis. Surprisingly, by tracking individual exocytic and endocytic events, we found that vesicles with new membrane are deposited to the cleavage furrow relatively evenly during contractile-ring constriction, but the rim of the cleavage furrow is the main site for endocytosis. Fusion of vesicles with the plasma membrane requires vesicle tethers. Our data suggest that the transport particle protein II (TRAPP-II) complex and Rab11 GTPase Ypt3 help to tether secretory vesicles or tubulovesicular structures along the cleavage furrow while the exocyst tethers vesicles at the rim of the division plane. We conclude that the exocyst and TRAPP-II complex have distinct localizations at the division site, but both are important for membrane expansion and exocytosis during cytokinesis.

Two putative vesicle tethers—the exocyst and TRAPP-II complexes—localize differently at the division plane to ensure efficient plasma-membrane deposition along the whole cleavage furrow during cytokinesis in the fission yeast Schizosaccharomyces pombe.

Cytokinesis partitions a mother cell into two daughter cells at the end of each cell-division cycle. A significant amount of new plasma membrane is needed at the cleavage furrow during cytokinesis in many cell types. Membrane expansion is achieved through the balance of exocytosis and endocytosis. It is poorly understood where and when the membrane is deposited and retrieved during cytokinesis. By tracking individual vesicles with high spatiotemporal resolution and using electron microscopy, we found that new membrane is deposited relatively evenly along the cleavage furrow in fission yeast, while the rim of the division plane is the predominant site for endocytosis. The secretory vesicles/compartments carrying new membrane are mainly delivered along formin-nucleated actin cables by myosin-V motors. Surprisingly, we find that both exocytosis and endocytosis at the division site are ramped up before contractile-ring constriction and last until daughter-cell separation. We discovered that two putative vesicle tethers, the exocyst and TRAPP-II complexes, localize to different sites at the cleavage furrow to promote tethering of different, yet overlapping, classes of secretory vesicles/compartments for exocytosis and new membrane deposition.

A bifractal nature of reticular patterns induced by oxygen plasma on polymer films

Plasma etching was demonstrated to be a promising tool for generating self-organized nano-patterns on various commercial films. Unfortunately, dynamic scaling approach toward fundamental understanding of the formation and growth of the plasma-induced nano-structure has not always been straightforward. The temporal evolution of self-aligned nano-patterns may often evolve with an additional scale-invariance, which leads to breakdown of the well-established dynamic scaling law. The concept of a bifractal interface is successfully applied to reticular patterns induced by oxygen plasma on the surface of polymer films. The reticular pattern, composed of nano-size self-aligned protuberances and underlying structure, develops two types of anomalous dynamic scaling characterized by super-roughening and intrinsic anomalous scaling, respectively. The diffusion and aggregation of short-cleaved chains under the plasma environment are responsible for the regular distribution of the nano-size protuberances. Remarkably, it is uncovered that the dynamic roughening of the underlying structure is governed by a relaxation mechanism described by the Edwards-Wilkinson universality class with a conservative noise. The evidence for the basic phase, characterized by the negative roughness and growth exponents, has been elusive since its first theoretical consideration more than two decades ago.

Mechanistic insights into the anchorage of the contractile ring by anillin and Mid1

Anillins and Mid1 are scaffold proteins that play key roles in anchorage of the contractile ring at the cell equator during cytokinesis in animals and fungi, respectively. Here, we report crystal structures and functional analysis of human anillin and S. pombe Mid1. The combined data show anillin contains a cryptic C2 domain and a Rho-binding domain. Together with the tethering PH domain, three membrane-associating elements synergistically bind to RhoA and phospholipids to anchor anillin at the cleavage furrow. Surprisingly, Mid1 also binds to the membrane through a cryptic C2 domain. Dimerization of Mid1 leads to high affinity and preference for PI(4,5)P2, which stably anchors Mid1 at the division plane, bypassing the requirement for Rho GTPase. These findings uncover the unexpected general machinery and the divergent regulatory logics for the anchorage of the contractile ring through the anillin/Mid1 family proteins from yeast to humans.

Abstract 712: Screening of Thrombolytic Agents in vivo Using a Novel Zebrafish Model of Ischemic Stroke Induced by Photochemical Thrombosis

Background: Timely thrombolytic therapy for acute ischemic stroke is important for improving neurological prognosis. Screening of thrombolytic agents on contemporary animal models of focal ischemic stroke is generally difficult as they require sophisticated surgical procedures such as induction of cerebral artery occlusion through mechanical ligation. Herein we seek to develop a novel zebrafish (Danio rerio) model of acute ischemic stroke for screening of thrombolytic drugs.

Methods: All experiments were performed on a modified confocal optical microscope, which allows the induction of thrombosis at a selected blood vessel of larval zebrafish and the imaging of thrombotic and thrombolytic processes in real time. To initiate photochemical thrombosis, a 532-nm laser was focused at a blood vessel of a larva (4 dpf) that had been injected with a photosensitizer (rose bengal). To test the thrombolytic activity of tPA, we injected tPA to the blood vessel of a larval with a thrombus that partially occluded the blood flow.

Results: Through photochemical means, we induced endothelial injury at selected blood vessel which subsequently triggered thrombosis. We show that an occlusion at the 1st branch of central artery drastically diminished the hemodynamics and cardiac function of larval zebrafish and impaired their capability to maintain balance during swimming whereas that at the basilar artery resulted in a high death rate. Immunofluorescent imaging shows that the photochemically induced thrombus comprised fibrins and platelets. After the injection of tPA to a larval with a partially occluded blood vessel, the fibrin mesh on the thrombus appeared sparse and limp which eventually led to the restoration of blood flow.

Conclusions: Our zebrafish model of ischemic stroke is convenient to adapt and is highly reproducible. This model can potentially become an effective platform that benefits the screening of thrombolytic agents and the optimization of their dose.

Regulation of spindle pole body assembly and cytokinesis by the centrin-binding protein Sfi1 in fission yeast

A previous model suggested doubling of Sfi1 as the first step of SPB assembly. Here it is shown that Sfi1 is gradually recruited to SPBs throughout the cell cycle. Conserved tryptophans in Sfi1 are required for its equal partitioning during mitosis, and unequal partitioning of Sfi1 underlies SPB assembly and mitotic defects in the next cell cycle.

Centrosomes play critical roles in the cell division cycle and ciliogenesis. Sfi1 is a centrin-binding protein conserved from yeast to humans. Budding yeast Sfi1 is essential for the initiation of spindle pole body (SPB; yeast centrosome) duplication. However, the recruitment and partitioning of Sfi1 to centrosomal structures have never been fully investigated in any organism, and the presumed importance of the conserved tryptophans in the internal repeats of Sfi1 remains untested. Here we report that in fission yeast, instead of doubling abruptly at the initiation of SPB duplication and remaining at a constant level thereafter, Sfi1 is gradually recruited to SPBs throughout the cell cycle. Like an sfi1Δ mutant, a Trp-to-Arg mutant (sfi1-M46) forms monopolar spindles and exhibits mitosis and cytokinesis defects. Sfi1-M46 protein associates preferentially with one of the two daughter SPBs during mitosis, resulting in a failure of new SPB assembly in the SPB receiving insufficient Sfi1. Although all five conserved tryptophans tested are involved in Sfi1 partitioning, the importance of the individual repeats in Sfi1 differs. In summary, our results reveal a link between the conserved tryptophans and Sfi1 partitioning and suggest a revision of the model for SPB assembly.

A Feasibility Study of a Tilted Head Position in Helical Tomotherapy for Fractionated Stereotactic Radiotherapy of Intracranial Malignancies

Herein, we evaluated the feasibility of placing patients in a tilted head position as part of routine clinical practice for fractionated stereotactic radiotherapy (FSRT) of intracranial tumors using helical tomotherapy (HT), by assessing its dosimetric benefit and setup accuracy. We reviewed treatment plans of four cases that were to receive FSRT for brain lesions in normal and head-tilted positions. These patients underwent two computed tomography (CT) scans: first in the normal supine position and then in the supine position with the head tilted at a 458 angle. Two separate HT plans for each position were generated in these four patients, using the same planning parameters. Plans were compared for target conformity and dose homogeneity. Maximum and average doses to critical organs, including normal brain, brain stem, optic chiasm, optic nerves, and the eyes, were considered. To evaluate setup accuracy, patient movement during treatment was assessed by post-treatment megavoltage CT scans. Both HT plans achieved similar conformal and homogeneous dose coverage to the target. Head-tilted HT delivered lower average and maximum doses to critical organs in the cases where the tumor was located on the same plane with critical organs, particularly when they were not directly attached. Placement in the head-tilted position without a mouthpiece allowed for increased patient movement during treatment, while use of a mouthpiece reduced patient movement to even less than that observed for normal setup in the supine position. This pilot study showed that placement in a tilted head position for FSRT of intracranial tumors using HT may be of clinical use, but depends on the tumor location.

Contractile-ring assembly in fission yeast cytokinesis: Recent advances and new perspectives

The fission yeast Schizosaccharomyces pombe is an excellent model organism to study cytokinesis. Here, we review recent advances on contractile-ring assembly in fission yeast. First, we summarize the assembly of cytokinesis nodes, the precursors of a normal contractile ring. IQGAP Rng2 and myosin essential light chain Cdc4 are recruited by the anillin-like protein Mid1, followed by the addition of other cytokinesis node proteins. Mid1 localization on the plasma membrane is stabilized by interphase node proteins. Second, we discuss proteins and processes that contribute to the search, capture, pull, and release mechanism of contractile-ring assembly. Actin filaments nucleated by formin Cdc12, the motor activity of myosin-II, the stiffness of the actin network, and severing of actin filaments by cofilin all play essential roles in contractile-ring assembly. Finally, we discuss the Mid1-independent pathway for ring assembly, and the possible mechanisms underlying the ring maturation and constriction. Collectively, we provide an overview of the current understanding of contractile-ring assembly and uncover future directions in studying cytokinesis in fission yeast.

Radiofrequency ablation combined with transcatheter arterial embolisation in rabbit liver: investigation of the ablation zone according to the time interval between the two therapies

OBJECTIVES

This study was designed to evaluate the extent of the radiofrequency ablation zone in relation to the time interval between transcatheter arterial embolisation (TAE) and radiofrequency ablation (RFA) and, ultimately, to determine the optimal strategy of combining these two therapies for hepatocellular carcinoma.

METHODS

15 rabbits were evenly divided into three groups: Group A was treated with RFA alone; Group B was treated with TAE immediately followed by RFA; and Group C was treated with TAE followed by RFA 5 days later. All animals underwent perfusion CT (PCT) scans immediately after RFA. Serum liver transaminases were measured to evaluate acute liver damage. Animals were euthanised for pathological analysis of ablated tissues 10 days after RFA. Non-parametric analyses were conducted to compare PCT indices, the RFA zone and liver transaminase levels among the three experimental groups.

RESULTS

Group B showed a significantly larger ablation zone than the other two groups. Arterial liver perfusion and hepatic perfusion index represented well the perfusion decrease after TAE on PCT. Although Group B showed the most elevated liver transaminase levels at 1 day post RFA, the enzymes decreased to levels that were not different from the other groups at 10 days post-RFA.

CONCLUSIONS

When combined TAE and RFA therapy is considered, TAE should be followed by RFA as quickly as possible, as it can be performed safely without serious hepatic deterioration, despite the short interval between the two procedures.

Characterization of Mid1 domains for targeting and scaffolding in fission yeast cytokinesis

Division-site selection and contractile-ring assembly are two crucial steps in cytokinesis. In fission yeast, the anillin-like Mid1 protein specifies the division site at the cell equator by assembling cortical nodes, the precursors of the contractile ring. Thus, Mid1 is essential for linking the positional cues for the cleavage site to contractile-ring formation. However, how Mid1 domains cooperate to regulate cytokinesis is poorly understood. Here we unravel the functions of different Mid1 domains (motifs) by a series of truncations. We report that the conserved PH domain stabilizes Mid1 in nodes by binding to lipids and is required for Mid1 cortical localization during interphase in the absence of Cdr2 kinase. Mid1 lacking an internal region that is approximately one third of the full-length protein has higher nuclear and cortical concentration and suppresses the division-site positioning defects in cells with a deletion of the dual-specificity tyrosine-regulated kinase Pom1. The N-terminus of Mid1 physically interacts with cytokinesis node proteins. When fused to cortical node protein Cdr2, Mid1(1-100) is sufficient to assemble cytokinesis nodes and the contractile ring. Collectively, our study recognizes domains regulating Mid1 cortical localization and reveals domains sufficient for contractile-ring assembly.

Roles of putative Rho-GEF Gef2 in division-site positioning and contractile-ring function in fission yeast cytokinesis

How Rho-GEFs and Rho GTPases regulate division-site selection during cytokinesis in fission yeast is unknown. The Rho-GEF Gef2 interacts with the anillin Mid1 to regulate contractile-ring positioning and assembly in coordination with the polo kinase Plo1. In addition, Gef2 is involved in contractile-ring stability and disassembly.

Cytokinesis is crucial for integrating genome inheritance and cell functions. In multicellular organisms, Rho-guanine nucleotide exchange factors (GEFs) and Rho GTPases are key regulators of division-plane specification and contractile-ring formation during cytokinesis, but how they regulate early steps of cytokinesis in fission yeast remains largely unknown. Here we show that putative Rho-GEF Gef2 and Polo kinase Plo1 coordinate to control the medial cortical localization and function of anillin-related protein Mid1. The division-site positioning defects of gef2∆ plo1-ts18 double mutant can be partially rescued by increasing Mid1 levels. We find that Gef2 physically interacts with the Mid1 N-terminus and modulates Mid1 cortical binding. Gef2 localization to cortical nodes and the contractile ring depends on its last 145 residues, and the DBL-homology domain is important for its function in cytokinesis. Our data suggest the interaction between Rho-GEFs and anillins is an important step in the signaling pathways during cytokinesis. In addition, Gef2 also regulates contractile-ring function late in cytokinesis and may negatively regulate the septation initiation network. Collectively, we propose that Gef2 facilitates and stabilizes Mid1 binding to the medial cortex, where the localized Mid1 specifies the division site and induces contractile-ring assembly.

Assembly and architecture of precursor nodes during fission yeast cytokinesis

Mapping of fission yeast precursor node interaction modules and assembly reveals important steps in contractile ring assembly.

The contractile ring is essential for cytokinesis in most fungal and animal cells. In fission yeast, cytokinesis nodes are precursors of the contractile ring and mark the future cleavage site. However, their assembly and architecture have not been well described. We found that nodes are assembled stoichiometrically in a hierarchical order with two modules linked by the positional marker anillin Mid1. Mid1 first recruits Cdc4 and IQGAP Rng2 to form module I. Rng2 subsequently recruits the myosin-II subunits Myo2 and Rlc1. Mid1 then independently recruits the F-BAR protein Cdc15 to form module II. Mid1, Rng2, Cdc4, and Cdc15 are stable node components that accumulate close to the plasma membrane. Both modules recruit the formin Cdc12 to nucleate actin filaments. Myo2 heads point into the cell interior, where they efficiently capture actin filaments to condense nodes into the contractile ring. Collectively, our work characterizing the assembly and architecture of precursor nodes defines important steps and molecular players for contractile ring assembly.

Caenorhabditis elegans TLK-1 controls cytokinesis by localizing AIR-2/Aurora B to midzone microtubules

Defects in chromosome condensation, segregation or cytokinesis during mitosis disrupt genome integrity and cause organismal death or tumorigenesis. The conserved kinase AIR-2/Aurora B is required for normal execution of all these important mitotic events in Caenorhabditis elegans. TLK-1 has been recently shown to be a substrate and activator of AIR-2 in the presence of another AIR-2 activator ICP-1/INCENP, and to cooperate with AIR-2 to ensure proper mitotic chromosome segregation. However, whether TLK-1 may contribute to chromosome condensation or cytokinesis is unclear. A time-lapse microscopy analysis showed that tlk-1 mutants are defective in chromosome condensation and cytokinesis, in addition to chromosome segregation, during mitosis. Our data indicate that TLK-1 contributes to chromosome condensation and segregation, at least in part, in a manner that is distinct from the ICP-1-mediated mechanism and does not involve loading AIR-2 or condensin proteins to mitotic chromosomes. Moreover, TLK-1 functions in cytokinesis by localizing AIR-2 to the midzone microtubules. The localization pattern of TLK-1 is different from those of ICP-1 and AIR-2, revealing differences in dynamic regulation and association of TLK-1 and ICP-1 towards AIR-2 in vivo. Interestingly, human TLK2 could functionally substitute for tlk-1, suggesting that the mitotic roles of TLK members might be evolutionarily conserved.

Roles of formin nodes and myosin motor activity in Mid1p-dependent contractile-ring assembly during fission yeast cytokinesis

Two prevailing models have emerged to explain the mechanism of contractile-ring assembly during cytokinesis in the fission yeast Schizosaccharomyces pombe: the spot/leading cable model and the search, capture, pull, and release (SCPR) model. We tested some of the basic assumptions of the two models. Monte Carlo simulations of the SCPR model require that the formin Cdc12p is present in >30 nodes from which actin filaments are nucleated and captured by myosin-II in neighboring nodes. The force produced by myosin motors pulls the nodes together to form a compact contractile ring. Live microscopy of cells expressing Cdc12p fluorescent fusion proteins shows for the first time that Cdc12p localizes to a broad band of 30-50 dynamic nodes, where actin filaments are nucleated in random directions. The proposed progenitor spot, essential for the spot/leading cable model, usually disappears without nucleating actin filaments. alpha-Actinin ain1 deletion cells form a normal contractile ring through nodes in the absence of the spot. Myosin motor activity is required to condense the nodes into a contractile ring, based on slower or absent node condensation in myo2-E1 and UCS rng3-65 mutants. Taken together, these data provide strong support for the SCPR model of contractile-ring formation in cytokinesis.

Subungual glomus tumours of the hand: diagnosis and outcome of the transungual approach

We report 17 patients with a subungual glomus tumour. All complained of pain and tenderness when touched, and nine patients experienced severe pain in the cold. A transungual approach with nail plate avulsion on one side was used in all cases. A surgical microscope was used to localise and dissect the tumour and to repair the nail bed and matrix. This method has produced good results, without local recurrence or postoperative nail plate deformity.

Influence of jasmonic acid on endogenous gibberellin and abscisic acid in salt-stressed chard plant

The endogenous gibberellin (GA) and abscisic acid (ABA) contents as an effect of different application times of jasmonic acid (JA) in chard seedlings exposed to salt stress were investigated. Endogenous ABA content was increased by JA treatment after NaCl treatment, rather than after JA application before NaCl treatment. JA application after NaCl treatment caused higher ABA content than treatment with 160 mM NaCl alone. Total gibberellin content decreased after NaCl stress, but NaCl-reduction in total GA contents counteracted by exogenous JA. Total endogenous GA contents were increased in JA treatment after NaCl and were highest at 24 hr of JA application before NaCl exposure. JA treatment promoted the increase of dry weight compared to chard plant exposed to 160 mM NaCl. Thus, JA presumably induces gibberellin biosynthesis showing the promotion of growth and dry weight of chard plants under salt stress.

Coexistence of superconductivity and antiferromagnetism probed by simultaneous nuclear magnetic resonance and electrical transport in (TMTSF)2PF6 system

We report simultaneous NMR and electrical transport experiments in the pressure range near the boundary of the antiferromagnetic spin density wave (SDW) insulator and the metallic/superconducting (SC) phase in (TMTSF)2PF6. Measurements indicate a tricritical point separating a line of second-order SDW/metal transitions from a line of first-order SDW/metal(SC) transitions with coexistence of macroscopic regions of SDW and metal(SC) order, with little mutual interaction but strong hysteretic effects. NMR results quantify the fraction of each phase.

Analytical approach for sound attenuation in perforated dissipative silencers with inlet/outlet extensions

The acoustic attenuation performance of perforated dissipative circular expansion chambers with inlet/outlet extensions is investigated. The eigenvalues and eigenfunctions of the sound field are analytically determined in the extended inlet/outlet circular ducts, upstream/downstream end annular dissipative chambers, and the central perforated dissipative expansion chamber. Utilizing the continuity conditions of velocity/pressure at the interfaces the transmission loss is predicted by a two-dimensional analytical approach. For a specific configuration, such predictions are compared with both experiments and a three-dimensional computational solution based on the substructure boundary element technique, showing a reasonable agreement. The analytical results for the effect of the absorbent resistivity, duct porosity, and geometryon the acoustic attenuation performance are discussed in detail.

Helmholtz resonator lined with absorbing material

A closed-form, two-dimensional analytical solution is developed to investigate the acoustic performance of a concentric circular Helmholtz resonator lined with fibrous material. The effect of density and the thickness of the fibrous material in the cavity is examined on the resonance frequency and the transmission loss. With the expressions for the eigenvalue and eigenfunction in the cavity, the transmission loss is obtained for a piston-driven model by applying a pressure/velocity matching technique. The results from the analytical methods are compared to the numerical predictions from a three-dimensional boundary element method and the experimental data obtained from an impedance tube setup. It is shown that the acoustic performance of a Helmholtz resonator may be modified considerably by the density and thickness of the fibrous material without changing the cavity dimensions.

Inhibitory effect of a naphthazarin derivative, S64, on heat shock factor (Hsf) activation and glutathione status following hypoxia

The presence of hypoxic cells in solid tumors has long been considered a problem in cancer treatment. Resistance of hypoxic cells to ionizing radiation and anticancer drugs has in part been attributed to changes in altered gene expression by hypoxia. We previously reported an activation of heat shock factor (Hsf) in murine tumor RIF cells following hypoxia and suggested that a subsequent accumulation of heat shock protein(s) (Hsp) is likely to contribute to the malignant progression of hypoxic tumor cells (Baek et al., 2001). In this study, we showed that hypoxia induced a DNA-binding activity of Hsf and activation of hsp70 gene expression in colon cancer Clone A cells, and that a naphthazarin derivative, S64, significantly inhibited the hypoxia-inducible hsp70 gene expression in Clone A cells. We also showed that S64 significantly reduced the cellular glutathione levels in this cell line. Considering the proposed effects of Hsp and glutathione on radiation and chemotherapy sensitivity, we suggest that the inhibitory effects of S64 on Hsf activation and cellular glutathione levels have potentially important clinical implications. We believe that the previously reported in vitro and in vivo anti-tumor effect of S64 (Song et al., 2000a, 2001) might be attributed, at least in part, to its effect on Hsf activation and/or glutathione depletion. We also believe that the detailed molecular mechanisms underlying the effects of S64 on Hsf and glutathione level following hypoxia deserve a more rigorous future study, the results of which could offer novel strategy to manipulate the resistance mechanisms of solid tumors.

Giant Nernst effect and lock-in currents at magic angles in (TMTSF)2PF6

We have measured the thermoelectric signal along the a axis in (TMTSF)2PF6 at 10 kbar as a function of the orientation of the applied magnetic field. Resonantlike Nernst signals were found with a dramatic sign change as the field was rotated through the "Lebed magic angles." The sign change indicates that the electrical current is "locked in" to the magic angle (interchain) directions for field alignment close to, but on either side of, the magic angles. The amplitude of signals near these angles is many orders of magnitude larger than expected from conventional Boltzmann transport theory.

Critical field enhancement near a superconductor-insulator transition

We have discovered a phenomenon where the orbital pair breaking effect is reduced, if not eliminated. It appears as a striking enhancement in the upper critical field H(c2) for (TMTSF)2PF6 and a strong upward curvature in the critical field versus temperature in the region of pressure-temperature phase space near the superconductor-spin density wave insulator boundary. A simple model based on self-consistently dividing the superconductor into layers explains the observations remarkably well and provides a unique way around orbital frustration and toward higher critical fields.

Triplet superconductivity in an organic superconductor probed by NMR Knight shift

The nature of the superconducting state in quasi-one-dimensional organic conductors has remained controversial since its discovery. Here we present results of (77)Se NMR Knight shift (K(s)) experiments in (TMTSF)(2)PF(6) under 7 kbar of pressure with a magnetic field aligned along the most conducting a axis. We find no noticeable shift in K(s) upon cooling through the superconducting transition. Since K(s) directly probes the spin susceptibility chi(s), the fact that chi(s) remains unchanged through the superconducting transition strongly suggests spin-triplet superconductivity.

Abdominopelvic actinomycosis involving the gastrointestinal tract: CT features

PURPOSE

To assess the computed tomographic (CT) features of abdominopelvic actinomycosis involving the gastrointestinal tract.

MATERIALS AND METHODS

CT scans were analyzed in 18 patients with pathologically proved abdominopelvic actinomycosis involving the gastrointestinal tract. Eight patients had a history of using intrauterine contraceptive devices. Bowel site, wall thickness, length, bowel involvement patterns, inflammatory infiltration, and features of peritoneal or pelvic mass, if present, were evaluated at CT.

RESULTS

Of the gastrointestinal tract, the sigmoid colon was most commonly involved (50%). All patients showed concentric (n = 15) or eccentric (n = 3) bowel wall thickening, with a mean thickness of 1.2 cm and a mean length of 8.3 cm. The thickened bowel enhanced homogeneously in nine patients and heterogeneously in the other nine. Inflammatory infiltration was mostly diffuse and severe. In 17 patients, a peritoneal or pelvic mass (mean maximum diameter, 3.2 cm) was seen adjacent to the involved bowel and appeared to be heterogeneously enhanced in most cases; infiltration into the abdominal wall was seen in four patients.

CONCLUSION

Actinomycosis should be included in the differential diagnosis when CT scans show bowel wall thickening and regional pelvic or peritoneal mass with extensive infiltration, especially in patients with abdominal pain, fever, leukocytosis, or long-term use of intrauterine contraceptive devices.

Signal transduction through Vav-2 participates in humoral immune responses and B cell maturation

B and T lymphocytes develop normally in mice lacking the guanine nucleotide exchange factor Vav-2. However, the immune responses to type II thymus-independent antigen as well as the primary response to thymus-dependent (TD) antigen are defective. Vav-2-deficient mice are also defective in their ability to switch immunoglobulin class, form germinal centers and generate secondary immune responses to TD antigens. Mice lacking both Vav-1 and Vav-2 contain reduced numbers of B lymphocytes and display a maturational block in the development of mature B cells. B cells from Vav-1(-/-)Vav-2(-/-) mice respond poorly to antigen receptor triggering, both in terms of proliferation and calcium release. These studies show the importance of Vav-2 in humoral immune responses and B cell maturation.

An anatomic comparison of the skin of five donor sites for dermal fat graft

Kim performed more than 3,000 augmentation rhinoplasties using the dermal fat graft. He preferred the sacral area as the donor site over other areas because the dermis is thick and the fat is more compact. The authors conducted a comparative study of the thickness of the epidermis and dermis, and the numbers of fibroblasts and fibrocytes in the dermis of the abdominal wall, groin, lateral gluteal area, gluteal fold, and sacrum of 7 adult cadavers. The sacrum had the thickest epidermis (86.1 +/- 7.8 microm) and dermis (1,510.7 +/- 201.7 microm), and the groin had the thinnest epidermis (57.3 +/- 22.9 microm) and dermis (783.3 +/- 244.5 microm). The dermal thickness of the abdomen, lateral gluteal area, and gluteal fold was 913.3 +/- 271.7 microm, 1,018.7 +/- 305.6 microm, and 1,107.0 +/- 272.6 microm respectively. The sacral dermis was significantly thicker than the other four sites (p < 0.008), and the groin dermis was the thinnest (p < 0.039). The number of fibroblasts and fibrocytes in the sacral area and the gluteal skin folds was significantly higher than the other areas (p < 0.05). The sacral area, gluteal fold, and lateral gluteal region had relatively thicker panniculus adiposus than the abdomen and groin. The panniculus adiposus of the sacral skin was especially well developed and was comprised of several compact layers that were connected by parallel, thick collagen fibers. The authors conclude that the sacral skin is a suitable donor site for dermal grafting because its dermis has more fibroblasts and fibrocytes than the other areas studied, and its dermis is more viable and durable.

MR imaging of shaken baby syndrome manifested as chronic subdural hematoma

Shaken baby syndrome (SBS) is a form of child abuse that can cause significant head injuries, of which subdural hematoma (SDH) is the most common manifestation. We report the MRI findings of chronic SDH in three cases of SBS, involving two-, three- and eight-month-old babies. The SDH signal was mostly low on T1-weighted images and high on T2-weighted images, suggesting chronic SDH. In chronic SDH, a focal high signal on T1-weighted images was also noted, suggesting rebleeding. Contrast-enhanced MRI revealed diffuse dural enhancement.

Selective activation of the c-Jun N-terminal protein kinase pathway during 4-hydroxynonenal-induced apoptosis of PC12 cells

The by-product of lipid peroxidation, 4-hydroxynonenal (HNE), was shown to cause apoptosis in PC12 cells. In this study, we investigated the molecular mechanism of HNE-induced apoptosis in these cells. Specifically, we determined the effect of HNE on the activities of mitogen-activated protein (MAP) kinases involved in early signal transduction. Within 15 to 30 min after HNE treatment, c-Jun N-terminal protein kinase (JNK) was maximally activated, before it returned to control level at 1 h post-treatment. In contrast, activities of extracellular signal-regulated kinase and p38 MAP kinase remained unchanged from their baseline levels. Stress-activated protein kinase kinase (SEK1), an upstream kinase of JNK, was also activated within 5 min after HNE treatment and remained activated for up to 60 min. Marked activation of the JNK pathway through SEK1 and apoptosis signal-regulating kinase 1 (ASK1), an upstream kinase of SEK1, was demonstrated by the transient transfection of cDNA for wild-type SEK1 or ASK1 together with JNK into COS-7 cells. Furthermore, significant reductions in JNK activation and HNE-induced cell death were observed when either of the dominant negative mutant of SEK1 or ASK1 was cotransfected with JNK. Pretreatment of PC12 cells with a survival-promoting agent, 8-(4-chlorophenylthio)-cAMP, prevented both the HNE-induced JNK activation and apoptosis. Nonaldehyde, a nontoxic aldehyde, neither caused apoptosis nor JNK activation. Pretreatment of PC12 cells with SB203580, a specific inhibitor of p38 MAP kinase, had no effect on HNE-induced apoptosis. All these data suggest that the selective JNK activation by HNE is critical for the apoptosis of PC12 cells and that the HNE-mediated apoptosis is likely to be mediated through the activation of the ASK1-SEK1-JNK pathway without activation of extracellular signal-regulated kinase or p38 MAP kinase.

Influence of phonation on basement membrane zone recovery after phonomicrosurgery: a canine model

The process of wound healing at the basement membrane zone of the vocal folds after phonomicrosurgery was investigated. The influence of phonation and the implied optimal period of voice rest were considered. Phonomicrosurgery was performed on both vocal folds of 20 adult dogs. In 10 dogs, the left recurrent laryngeal nerve was simultaneously resected to simulate iatrogenic voice rest; the remaining 10 dogs were allowed to phonate normally. The healing process of the vocal folds of each group was observed at 1, 2, 4, 8, and 12 weeks after surgery with immunohistochemical staining and transmission electron microscopy. In the voice rest group, the basement membrane was completely re-formed in 2 weeks, and the "cover" appeared completely rearranged by 8 weeks. The results of the phonation group were characterized by a delayed healing process and basement membrane changes. These results suggest that voice rest of at least 2 weeks after surgery may be beneficial and that vocal hygiene should be maintained for as long as 8 weeks.

Intraspecific variation in Cannabis sativa L. based on intergenic spacer region of chloroplast DNA

We analyzed the nucleotide sequences of the non-coding region of chloroplast DNA: the intergenic spacer between trnL (UAA) 3'exon and trnF (GAA). Two kinds of sequence, "type-1" and "type-2," were detected in 33 populations of Cannabis sativa. The length of the "type-1" fragment was 354 bp. In contrast, the "type-2" fragment from 3 populations was 353 bp long, with only one base deletion compared to "type-1." The fragment length from Humulus lupulus was 353 bp with a 1-bp deletion, and ten 1-bp substitutions compared to the sequences from C. sativa "type-1." Furthermore, we could clearly identify differences between C. sativa and H. lupulus using single-strand conformation polymorphism of PCR products (PCR-SSCP) analysis.

Radiologic findings of abdominal polyarteritis nodosa

OBJECTIVE

The purpose of this study was to evaluate the radiographic and imaging findings of seven patients with polyarteritis nodosa involving the abdomen.

CONCLUSION

Vasculitis should be considered when multiple abdominal organs have abnormal radiologic findings; however, angiography is necessary to specifically diagnose polyarteritis nodosa.