Suppression of creep-regime dynamics in epitaxial ferroelectric BiFeO3 films

Switching dynamics of ferroelectric materials are governed by the response of domain walls to applied electric field. In epitaxial ferroelectric films, thermally-activated ‘creep’ motion plays a significant role in domain wall dynamics, and accordingly, detailed understanding of the system’s switching properties requires that this creep motion be taken into account. Despite this importance, few studies have investigated creep motion in ferroelectric films under ac-driven force. Here, we explore ac hysteretic dynamics in epitaxial BiFeO₃ thin films, through ferroelectric hysteresis measurements, and stroboscopic piezoresponse force microscopy. We reveal that identically-fabricated BiFeO₃ films on SrRuO₃ or La_0.67Sr_0.33MnO₃ bottom electrodes exhibit markedly different switching behaviour, with BiFeO₃/SrRuO₃ presenting essentially creep-free dynamics. This unprecedented result arises from the distinctive spatial inhomogeneities of the internal fields, these being influenced by the bottom electrode’s surface morphology. Our findings further highlight the importance of controlling interface and defect characteristics, to engineer ferroelectric devices with optimised performance.

Switching bipolar hepatic radiofrequency ablation using internally cooled wet electrodes: comparison with consecutive monopolar and switching monopolar modes

OBJECTIVE

To evaluate whether switching bipolar radiofrequency ablation (SB-RFA) using three internally cooled wet (ICW) electrodes can induce coagulations >5 cm in porcine livers with better efficiency than consecutive monopolar (CM) or switching monopolar (SM) modes.

METHODS

A total of 60 coagulations were made in 15 in vivo porcine livers using three 17-gauge ICW electrodes and a multichannel radiofrequency (RF) generator. RF energy (approximately 200 W) was applied in CM mode (Group A, n = 20) for 24 min, SM mode for 12 min (Group B, n = 20) or switching bipolar (SB) mode for 12 min (Group C, n = 20) in in vivo porcine livers. Thereafter, the delivered RFA energy, as well as the shape and dimension of coagulations were compared among the groups.

RESULTS

Spherical- or oval-shaped ablations were created in 30% (6/20), 85% (17/20) and 90% (18/20) of coagulations in the CM, SM and SB groups, respectively (p = 0.003). SB-RFA created ablations >5 cm in minimum diameter (Dmin) in 65% (13/20) of porcine livers, whereas SM- or CM-RFA created ablations >5 cm in only 25% (5/20) and 20% (4/20) of porcine livers, respectively (p = 0.03). The mean Dmin of coagulations was significantly larger in Group C than in Groups A and B (5.1 ± 0.9, 3.9 ± 1.2 and 4.4 ± 1.0 cm, respectively, p = 0.002) at a lower delivered RF energy level (76.8 ± 14.3, 120.9 ± 24.5 and 114.2 ± 18.3 kJ, respectively, p < 0.001).

CONCLUSION

SB-RFA using three ICW electrodes can create coagulations >5 cm in diameter with better efficiency than do SM- or CM-RFA.

ADVANCES IN KNOWLEDGE

SB-RFA can create large, regular ablation zones with better time-energy efficiency than do CM- or SM-RFA.

Non-transcriptional regulation of NLRP3 inflammasome signaling by IL-4

Th2 cytokine IL-4 has been previously shown to suppress the production of proinflammatory cytokines in monocytes. However, the underlying molecular mechanism by which IL-4 signaling antagonizes proinflammatory responses is poorly characterized. In particular, whether IL-4 can modulate inflammasome signaling remains unknown. Here, we provide evidence that IL-4 suppresses NLRP3-dependent caspase-1 activation and the subsequent IL-1β secretion but does not inhibit absent in melanoma 2 (AIM2)- or NLRC4 (NOD-like receptor family, CARD domain-containing 4)-dependent caspase-1 activation in THP-1 and mouse bone marrow-derived macrophages. Upon lipopolysaccharide (LPS) or LPS/ATP stimulation, IL-4 markedly inhibited the assembly of NLRP3 inflammasome, including NLRP3-dependent ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain) oligomerization, NLRP3-ASC interaction and NLRP3 speck-like oligomeric structure formation. The negative regulation of NLRP3 inflammasome by IL-4 was not due to the impaired mRNA or protein production of NLRP3 and proinflammatory cytokines. Supporting this observation, IL-4 attenuated NLRP3 inflammasome activation even in reconstituted NLRP3-expressing macrophages in which NLRP3 expression is not transcriptionally regulated by TLR-NF-κB signaling. Furthermore, the IL-4-mediated suppression of NLRP3 inflammasome was independent of STAT6-dependent transcription and mitochondrial reactive oxygen species (ROS). Instead, IL-4 inhibited subcellular redistribution of NLRP3 into mitochondria and microtubule polymerization upon NLRP3-activating stimulation. Our results collectively suggest that IL-4 could suppress NLRP3 inflammasome activation in a transcription-independent manner, thus providing an endogenous regulatory machinery to prevent excessive inflammasome activation.

Top-up operation at Pohang Light Source-II

After three years of upgrading work, PLS-II (S. Shin, Commissioning of the PLS-II, JINST, January 2013) is now successfully operating. The top-up operation of the 3 GeV linear accelerator had to be delayed because of some challenges encountered, and PLS-II was run in decay mode at the beginning in March 2012. The main difficulties encountered in the top-up operation of PLS-II are different levels between the linear accelerator and the storage ring, the 14 narrow gap in-vacuum undulators in operation, and the full energy injection by 3 GeV linear accelerator. Large vertical emittance and energy jitter of the linac were the major obstacles that called for careful control of injected beam to reduce beam loss in the storage ring during injection. The following measures were taken to resolve these problems: (1) The high resolution Libera BPM (see http://www.i-tech.si) was implemented to measure the beam trajectory and energy. (2) Three slit systems were installed to filter the beam edge. (3) De-Qing circuit was applied to the modulator system to improve the energy stability of injected beam. As a result, the radiation by beam loss during injection is reduced drastically, and the top-up mode has been successfully operating since 19th March 2013. In this paper, we describe the experimental results of the PLS-II top-up operation and the improvement plan.

Barriers to mental health treatment: results from the WHO World Mental Health surveys

BACKGROUND

To examine barriers to initiation and continuation of mental health treatment among individuals with common mental disorders.

METHOD

Data were from the World Health Organization (WHO) World Mental Health (WMH) surveys. Representative household samples were interviewed face to face in 24 countries. Reasons to initiate and continue treatment were examined in a subsample (n = 63,678) and analyzed at different levels of clinical severity.

RESULTS

Among those with a DSM-IV disorder in the past 12 months, low perceived need was the most common reason for not initiating treatment and more common among moderate and mild than severe cases. Women and younger people with disorders were more likely to recognize a need for treatment. A desire to handle the problem on one's own was the most common barrier among respondents with a disorder who perceived a need for treatment (63.8%). Attitudinal barriers were much more important than structural barriers to both initiating and continuing treatment. However, attitudinal barriers dominated for mild-moderate cases and structural barriers for severe cases. Perceived ineffectiveness of treatment was the most commonly reported reason for treatment drop-out (39.3%), followed by negative experiences with treatment providers (26.9% of respondents with severe disorders).

CONCLUSIONS

Low perceived need and attitudinal barriers are the major barriers to seeking and staying in treatment among individuals with common mental disorders worldwide. Apart from targeting structural barriers, mainly in countries with poor resources, increasing population mental health literacy is an important endeavor worldwide.

Barriers to mental health treatment: results from the WHO World Mental Health surveys

BACKGROUND

To examine barriers to initiation and continuation of mental health treatment among individuals with common mental disorders.

METHOD

Data were from the World Health Organization (WHO) World Mental Health (WMH) surveys. Representative household samples were interviewed face to face in 24 countries. Reasons to initiate and continue treatment were examined in a subsample (n = 63,678) and analyzed at different levels of clinical severity.

RESULTS

Among those with a DSM-IV disorder in the past 12 months, low perceived need was the most common reason for not initiating treatment and more common among moderate and mild than severe cases. Women and younger people with disorders were more likely to recognize a need for treatment. A desire to handle the problem on one's own was the most common barrier among respondents with a disorder who perceived a need for treatment (63.8%). Attitudinal barriers were much more important than structural barriers to both initiating and continuing treatment. However, attitudinal barriers dominated for mild-moderate cases and structural barriers for severe cases. Perceived ineffectiveness of treatment was the most commonly reported reason for treatment drop-out (39.3%), followed by negative experiences with treatment providers (26.9% of respondents with severe disorders).

CONCLUSIONS

Low perceived need and attitudinal barriers are the major barriers to seeking and staying in treatment among individuals with common mental disorders worldwide. Apart from targeting structural barriers, mainly in countries with poor resources, increasing population mental health literacy is an important endeavor worldwide.

The influence of ritodrine alone or in combination with nifedipine on maternal cardiovascular side effects and pregnancy outcomes

OBJECTIVE

To compare the influence of ritodrine alone or in combination with nifedipine on maternal side effects and suppressing preterm labor.

MATERIALS AND METHODS

This retrospective study included 213 pregnancies with preterm labor (20-34 weeks) from May 2002 to April 2010 in Kyungpook National University Hospital in Daegu, Korea. Obstetric medical records were reviewed for both maternal characteristics and neonatal outcomes, including birth weight, Apgar score, admission to neonatal intensive care unit (NICU), ventilator support, and neonatal mortality. Maternal side effects such as tachycardia, pulmonary edema, and hyperglycemia were also reviewed.

RESULTS

Of 213 patients, 109 received ritodrine only and 104 were given ritodrine and nifedipine. There was no statistical difference between the two groups with regards to pregnancy outcomes and neonatal complications. Pregnancy prolongation over seven days was achieved more in the combination therapy group, with borderline statistical significance (59.6% vs. 72.1%, p = 0.055). Sixty-nine cases experienced maternal side effects; four cases were categorized as serious and 65 cases were mild.

CONCLUSION

In the treatment of preterm labor, the combination regimen of ritodrine and nifedipine can be more effective than ritodrine alone for prolonging gestation over seven days. Moreover, as the combination did not cause severe maternal side effects, it may be considered as a safe and effective method to prolong gestation in patients with preterm labor.

The mitochondrial antiviral protein MAVS associates with NLRP3 and regulates its inflammasome activity

NLRP3 assembles an inflammasome complex that activates caspase-1 upon sensing various danger signals derived from pathogenic infection, tissue damage, and environmental toxins. How NLRP3 senses these various stimuli is still poorly understood, but mitochondria and mitochondrial reactive oxygen species have been proposed to play a critical role in NLRP3 activation. In this article, we provide evidence that the mitochondrial antiviral signaling protein MAVS associates with NLRP3 and facilitates its oligomerization leading to caspase-1 activation. In reconstituted 293T cells, full-length MAVS promoted NLRP3-dependent caspase-1 activation, whereas a C-terminal transmembrane domain-truncated mutant of MAVS (MAVS-ΔTM) did not. MAVS, but not MAVS-ΔTM, interacted with NLRP3 and triggered the oligomerization of NLRP3, suggesting that mitochondrial localization of MAVS and intact MAVS signaling are essential for activating the NLRP3 inflammasome. Supporting this, activation of MAVS signaling by Sendai virus infection promoted NLRP3-dependent caspase-1 activation, whereas knocking down MAVS expression clearly attenuated the activation of NLRP3 inflammasome by Sendai virus in THP-1 and mouse macrophages. Taken together, our results suggest that MAVS facilitates the recruitment of NLRP3 to the mitochondria and may enhance its oligomerization and activation by bringing it in close proximity to mitochondrial reactive oxygen species.

Cobalt Chloride-induced Hypoxia Ameliorates NLRP3-Mediated Caspase-1 Activation in Mixed Glial Cultures

Hypoxia has been shown to promote inflammation, including the release of proinflammatory cytokines, but it is poorly investigated how hypoxia directly affects inflammasome signaling pathways. To explore whether hypoxic stress modulates inflammasome activity, we examined the effect of cobalt chloride (CoCl₂)-induced hypoxia on caspase-1 activation in primary mixed glial cultures of the neonatal mouse brain. Unexpectedly, hypoxia induced by oxygen-glucose deprivation or CoCl₂ treatment failed to activate caspase-1 in microglial BV-2 cells and primary mixed glial cultures. Of particular interest, CoCl₂-induced hypoxic condition considerably inhibited NLRP3-dependent caspase-1 activation in mixed glial cells, but not in bone marrow-derived macrophages. CoCl₂-mediated inhibition of NLRP3 inflammasome activity was also observed in the isolated brain microglial cells, but CoCl₂ did not affect poly dA:dT-triggered AIM2 inflammasome activity in mixed glial cells. Our results collectively demonstrate that CoCl₂-induced hypoxia may negatively regulate NLRP3 inflammasome signaling in brain glial cells, but its physiological significance remains to be determined.

Differentiation of recurrent tumor and posttreatment changes in head and neck squamous cell carcinoma: application of high b-value diffusion-weighted imaging

BACKGROUND AND PURPOSE

High b-value DWI has been expected to have an additional diagnostic role and demonstrated some promising results in head and neck cancer. The aim of this study was to evaluate the diagnostic performance of DWI at a high b-value (b=2000 s/mm(2)) compared with a standard b-value (b=1000 s/mm(2)) and the ratio of ADC values of high and standard b-values for their ability to differentiate between recurrent tumor and posttreatment changes after the treatment of head and neck squamous cell carcinoma.

MATERIALS AND METHODS

A total of 33 patients diagnosed with head and neck squamous cell carcinoma were enrolled in the present study; all had contrast-enhancing lesions on follow-up MR imaging. All patients underwent single-shot echo-planar DWI at b=1000 s/mm(2) and b=2000 s/mm(2), and corresponding ADC maps were generated (ADC1000 and ADC2000, respectively). The mean ADC1000, ADC2000, and ADCratio (ADCratio = ADC2000/ADC1000 × 100) values were evaluated within a manually placed ROI with contrast-enhanced T1-weighted images as references. For the statistical analysis, we performed a Student t test and multivariate logistic regression.

RESULTS

The mean ADC1000 in recurrent tumor was significantly lower than that in posttreatment changes (P < .001), whereas the mean ADC2000 resulted in no significant difference (P = .365). The mean ADCratio was significantly higher in recurrent tumor than that in posttreatment changes (73.5 ± 7.2% vs 56.9 ± 8.8%, respectively; P < .001). Multivariate logistic regression analysis revealed that the ADCratio was the only independently differentiating variable (P = .024). The sensitivity, specificity, and accuracy of ADCratio were 95.0%, 69.2%, and 84.8%, respectively, by use of the optimal cutoff value of 62.6%.

CONCLUSIONS

We suggest that the ADCratio calculated from the ADC1000 and ADC2000 is a promising value for the differentiation of recurrent tumor and posttreatment changes in head and neck squamous cell carcinoma.

Ribotoxic stress through p38 mitogen-activated protein kinase activates in vitro the human pyrin inflammasome

Human pyrin with gain-of-function mutations in its B30.2/SPRY domain causes the autoinflammatory disease familial Mediterranean fever by assembling an ASC-dependent inflammasome that activates caspase-1. Wild-type human pyrin can also form an inflammasome complex with ASC after engagement by autoinflammatory PSTPIP1 mutants. How the pyrin inflammasome is activated in the absence of disease-associated mutations is not yet known. We report here that ribotoxic stress triggers the assembly of the human pyrin inflammasome, leading to ASC oligomerization and caspase-1 activation in THP-1 macrophages and in a 293T cell line stably reconstituted with components of the pyrin inflammasome. Knockdown of pyrin and selective inhibition of p38 MAPK greatly attenuated caspase-1 activation by ribotoxic stress, whereas expression of the conditional mutant ΔMEKK3:ER* allowed the activation of caspase-1 without ribotoxic stress. Disruption of microtubules by colchicine also inhibited pyrin inflammasome activation by ribotoxic stress. Together, our results indicate that ribotoxic stress activates the human pyrin inflammasome through a mechanism that requires p38 MAPK signaling and microtubule stability.

Tissue-specific expression of occludin, zona occludens-1, and junction adhesion molecule A in the duodenum, ileum, colon, kidney, liver, lung, brain, and skeletal muscle of C57BL mice

Tight junctions are the most apically positioned intercellular junction and play many roles such as securing adjacent cells, forming barriers from extracellular materials, and facilitating paracellular transport. Occludin and junction adhesion molecule A (JAM-A) are classified as transmembrane proteins that are directly involved in paracellular transport. Zona occludens-1 (ZO-1) is a protein that contains a PDZ domain which forms a binding site for other tight junction proteins. In this study, we assessed the differential expression of these tight junction components in various mouse organs including the intestine (duodenum, ileum, and colon), kidney, liver, lung, brain, and skeletal muscle. Realtime PCR and Western blot assays were performed to measure the gene and protein expression of occludin, JAM-A, and ZO-1. Similar levels of occludin gene expression were detected in all tissues except for skeletal muscle in which occludin expression was not found. The JAM-A and ZO-1 genes were highly expressed in all the tested tissues. Localization of occludin, JAM-A, and ZO-1 was determined by immunohistochemistry. These proteins were detected in the intercellular apical junctions in each tissue except for occludin (which was not observed in skeletal muscle). These immunostaining data were consistent with the gene expression profiles we obtained. Our results suggest that occludin, JAM-A, and ZO-1 genes are normally expressed in the intestine, kidney, liver, lung, and brain indicating that these factors may be essential for maintaining appropriate physiological concentration of ions, solutes and water.

Restoration of ASC expression sensitizes colorectal cancer cells to genotoxic stress-induced caspase-independent cell death

Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), an essential component of the inflammasome complex, is frequently silenced by epigenetic methylation in many tumor cells. Here, we demonstrate that restoration of ASC expression in human colorectal cancer DLD-1 cells, in which ASC is silenced by aberrant methylation, potentiated cell death mediated by DNA damaging agent. Contrarily, ASC knockdown in HT-29 cells rendered cells less susceptible to etoposide toxicity. The increased susceptibility of ASC-expressing DLD-1 cells to genotoxic stress was independent of inflammasome or caspase activation, but partially dependent on mitochondrial ROS production and JNK activation. Thus, our data suggest that ASC expression in cancer cells is an important factor in determining their susceptibility to chemotherapy.

98 THE EXPRESSION OF TIGHT JUNCTION GENES IN THE PLACENTA BY CALCIUM OR VITAMIN D DEFICIENCY IN WILD TYPE AND CaBP-9k OR CaBP-28k KNOCKOUT MICE

The placenta is responsible for calcium transport from mother to fetus. Tight junction genes are responsible for the passive paracellular pathway, which is one of the major calcium transport pathways. Therefore, we examined whether the tight junction genes are differently expressed in the placenta by calcium, vitamin D, or both deficiency. We also investigated the correlation between transcellular transport and paracellular transport by using calbindin-D9k (CaBP-9k), calbindin-D28K (CaBP-28k), or both knockout (KO) mice. We administrated C57BL/6 wild type and CaBP-D9K, CaBP-D28K KO, or both mice with calcium, vitamin D, or both deficiency diets for 19 days (during pregnant Day 0 to 18). The expression levels and localization of tight junction genes including zona occludens 1 (Zo-1), junction adhesion molecules A (Jam-A), and claudins (Cldn) were tested. The mRNA and protein expression of these genes were investigated by real-time PCR and Western blotting assay. Five samples from 3 animals for each treated group were used and the data analyzed using a one-way ANOVA. P-values <0.05 were considered statistically significant. The localization of the genes was also examined by immunohistochemistry. The mRNA and protein expressions of Cldn1 were increased in calcium and calcium/vitamin D deficient CaBP-D9K KO mice and in calcium/vitamin D deficient CaBP-D9/28K mice, whereas those of Zo-1 and Jam-A were not affected. Gene Cldn5 mRNA expression showed a decrease in CaBP-9k, CaBP-28k, or both KO mice compared with wild type mice. Interestingly, Cldn5 mRNA expression was augmented in vitamin D or calcium deficient CaBP-D9K KO mice. Other tested Cldns did not show significant changes in any dietary or CaBP KO conditions. All the tight junction genes were localized in the trophoblast layer of the placenta. Taken together, the expression of tight junction genes was dynamically regulated by different dietary conditions and in the condition that transcellular calcium transport was altered by ablation of CaBPs, suggesting that these genes were involved in the placental calcium homeostasis.

Salmonella Promotes ASC Oligomerization-dependent Caspase-1 Activation

Innate immune cells sense and respond to the cytoplasmic infection of bacterial pathogens through NLRP3, NLRC4 or AIM2 inflammasome depending on the unique molecular pattern of invading pathogens. The infection of flagellin- or type III secretion system (T3SS)-containing Gram-negative bacteria such as Salmonella enterica serovar Typhimurium (S. typhimurium) or Pseudomonas aeruginosa (P. aeruginosa) triggers NLRC4-dependent caspase-1 activation leading to the secretion of proinflammatory cytokines such as interleukin-1-beta (IL-1β) and IL-18. Previous studies have shown that apoptosis-associated speck-like protein containing a CARD (ASC) is also required for Salmonella-induced caspase-1 activation, but it is still unclear how ASC contributes to the activation of NLRC4 inflammasome in response to S. typhimurium infection. In this study, we demonstrate that S. typhimurium triggers the formation of ASC oligomer in a potassium depletion-independent manner as determined by in vitro crosslinking and in situ fluorescence imaging. Remarkably, inhibition of potassium efflux failed to block Salmonella-promoted caspase-1 activation and macrophage cell death. These results collectively suggest that ASC is substantially oligomerized to facilitate the activation of caspase-1 in response to S. typhimurium infection. Contrary to NLRP3 inflammasome, intracellular potassium depletion is not critical for NLRC4 inflammasome signaling by S. typhimurium.

Additional effects of bisphenol A and paraben on the induction of calbindin-D(9K) and progesterone receptor via an estrogen receptor pathway in rat pituitary GH3 cells

There are concerns about the combined estrogenic effects of chemicals since mixtures of these chemicals exist in our environment. This study investigated potential additional interactions between bisphenol A (BPA) and isobutylparaben (IBP), which are major xenoestrogens used in the manufacture of plastics, cosmetics, drugs, and other products. The combined effects of these two chemicals were analyzed by measuring the expression of calbindin-D(9k) (CaBP-9k) in rat pituitary cancer GH3 cells. GH3 cells were treated with single and combination doses of both chemicals (BPA single doses: 10(-7), 10(-6) and 10(-5) M; IBP single doses: 10(-7), 10(-6) and 10(-5) M, and each of the BPA and IBP doses combined). Prior to treatment, cells were temporarily transfected with a plasmid containing an ERE-luciferase reporter gene. Luciferase activity was measured as an indicator of ER activation by 17β-estradiol (E2), BPA, and IBP. BPA (10(-5) M) combined with IBP (10(-7) M and 10(-6) M) induced a significant increase in the luciferase activity. Twenty-four hours after treatment, dose-dependent effects were observed in both single and combined dose groups, and several combination doses induced significant increases in the expression of CaBP-9k and progesterone receptor (PR) at both transcriptional and translational levels. Pre-treatment with ICI 182,780, a pure estrogen antagonist, significantly reversed BPA- and IBP-induced CaBP-9k and PR upregulation in GH3 cells. Taken together, these results indicate that BPA and IBP may have additionally increased estrogenic potency via an estrogen receptor-mediated pathway.

Treatment outcome and safety of docetaxel as the third-line chemotherapy in advanced gastric cancer after progression or after failure of FOLFOX and FOLFIRI-based sequential chemotherapy

133

Background: We performed multicenter retrospective study to evaluate the activity and the safety of a docetaxel as the third-line chemotherapy in advanced gastric cancer (AGC) patients who had undergone oxaliplatin (FOLFOX) and irinotecan (FOLFIRI)-based chemotherapy regimens.

Methods: Thirty-eight patients with AGC previously treated were eligible for this study. Patients received docetaxel 30 mg/m2 +/- cisplatin 30 mg/m2 IV on day 1, 8 or docetaxel 60 mg/m2 +/- cisplatin 60 mg/m2 IV on day 1 every 3 weeks until disease progression, and responses were assessed after every two cycles according to RECIST criteria and toxicity was evaluated by NCI-CTC.

Results: Thirty-two out of 38 patients were evaluable for response. A total of 95.1 cycles of chemotherapy (median 2, range 0.5–7) were administered. Relative dose intensities of docetaxel and cisplatin were 93.4% and 87.8%, respectively. The overall response rate was 15.6% and the disease control rate was 50%. With a median follow-up duration of 3.1 months (range 0.3-14.3 months), 36 patients had disease progression, and 34 patients had died at the time of analysis. The median progression-free survival was 1.8 months (95% CI, 1.3–2.3 months). The median overall survival was 3.1 months (95% CI, 2.3–3.9 months). Grade 3 or 4 hematologic toxicities included neutropenia in thirteen patients (38.3%), febrile neutropenia in four patients (11.7%). and thrombocytopenia in one patient (2.9%). Other grade 3 or 4 toxicities included neuropathy in three patients (8.8%) and mucositis in two patients (5.9%). There were three treatment-related deaths (8.8%) caused by infection associated with neutropenia.

Conclusions: Salvage docetaxel chemotherapy in AGC patients failed in oxaliplatin and irinotecan-based treatment is not recommend routinely. However, selected patients with good performance status and sufficient albumin levels may have derived some survival benefits from salvage chemotherapy.

No significant financial relationships to disclose.

Subacute thyroiditis presenting as a focal lesion on [18F] fluorodeoxyglucose whole-body positron-emission tomography/CT

A 52-year-old man presented with subacute thyroiditis and showed an intensely hypermetabolic thyroid lesion on (18)F-FDG PET/CT. The patient also had coexisting chronic lymphocytic thyroiditis. The lesion of subacute thyroiditis revealed an SUV(max) of 9.1 g/mL and was ill-defined, heterogeneous, markedly hypoechoic, and hypovascular on US. Biopsy demonstrated histologic findings of subacute thyroiditis, which should be included in the differential diagnosis of an intensely hypermetabolic thyroid lesion on (18)F-FDG PET/CT.

Age differences in major depression: results from the National Comorbidity Survey Replication (NCS-R)

BACKGROUND

Although depression appears to decrease in late life, this could be due to misattribution of depressive symptom to physical disorders that increase in late life.

METHOD

We studied age differences in major depressive episodes (MDE) in the National Comorbidity Survey Replication, a national survey of the US household population. DSM-IV MDE was defined without organic exclusions or diagnostic hierarchy rules to facilitate analysis of co-morbidity. Physical disorders were assessed with a standard chronic conditions checklist and mental disorders with the WHO Composite International Diagnostic Interview (CIDI) version 3.0.

RESULTS

Lifetime and recent DSM-IV/CIDI MDE were significantly less prevalent among respondents aged 65 years than among younger adults. Recent episode severity, but not duration, was also lower among the elderly. Despite prevalence of mental disorders decreasing with age, co-morbidity of hierarchy-free MDE with these disorders was either highest among the elderly or unrelated to age. Co-morbidity of MDE with physical disorders, in comparison, generally decreased with age despite prevalence of co-morbid physical disorders usually increasing. Somewhat more than half of respondents with 12-month MDE received past-year treatment, but the percentage in treatment was lowest and most concentrated in the general medical sector among the elderly.

CONCLUSIONS

Given that physical disorders increase with age independent of depression, their lower associations with MDE in old age argue that causal effects of physical disorders on MDE weaken in old age. This result argues against the suggestion that the low estimated prevalence of MDE among the elderly is due to increased confounding with physical disorders.

Clinical implication of ERCC1 overexpression in advanced biliary tract adenocarcinoma patients treated with platinum-based palliative chemotherapy

e22018

Background: Several clinical studies have shown that Excision repair cross-complementation group1 (ERCC1) overexpression is associated with resistance to platinum-based chemotherapy and poor prognoses in several tumors. However these studies have never been tried for biliary tract cancer. The aim of this study was to evaluate the association between ERCC1 expression and treatment outcomes in advanced biliary tract adenocarcinoma patients treated with platinum-based palliative chemotherapy. Methods: We analyzed 45 patients with histologically confirmed adenocarcinoma of biliary tract at 5 institutions between January 2002 and March 2008. ERCC1 expression was assessed by immunohistochemistry from biopsy specimens. Results: ERCC1 expression was positive in 17 of 45 specimens (37.8%). 26 (57.8%) of 45 patients showed clinical benefits(including complete response, partial response and stable disease). Among 26 patients who obtained clinical benefits, seven (27%) were positive for ERCC1 expression and ninety (73%) were negative (p=0.079). With a median follow-up of 6.6 months (range, 0.9–39.4 months), median Progression free survival (PFS) and Overall survival (OS) were 4.4 months (95% CI, 3.2–5.6 months) and 8.5 months (95% CI, 6.1–10.9 months), respectively, for the total study population. On univariate analysis, PFS was 2.3 months for patients with ERCC1 positive tumor and 5.3 months for those with ERCC1 negative tumor (P = 0.053). However OS was significantly longer in the ERCC1-negative group than in the ERCC1-positive group (10.0 vs 4.4 months, respectively; P = 0.001). Other factors affecting the prolongation of OS were objective response rate (P = 0.016) and clinical benefits (P = 0.001). A Cox proportional hazard model showed that negative ERCC1 expression (hazard ratio 0.405, 95% CI, 0.200–0.820; P = 0.012) and clinical benefit (hazard ratio 0.183, 95% CI 0.080–0.420; P = 0.001) were significant independent prognostic factors for the prolongation of survival. Conclusions: These results suggest that advanced biliary tract adenocarcinoma patients with ERCC1-negative tumors show a survival benefit from palliative chemotherapy with a platinum- containing regimen.

No significant financial relationships to disclose.

Postoperative LV5FU2 combination chemotherapy in patients with curative resected advanced gastric cancer

e15660

Background: To illuminate the effect and toxicity of fortnightly low-dose leucovorin(LV) and fluorouracil(5FU) bolus plus continuous infusion(LV5FU2) postoperative chemotherapy(adjuvant) in patients with curative resected, advanced gastric cancer. Methods: Total 40 patients were enrolled in this study. All patients received LV 20mg/m2(bolus), 5FU 400mg/m2(bolus), 5FU 600mg/m2(24-hour continuous infusion) on day 1, 2, 15, and 16, every 4 weeks(LV5FU2), total 6 cycles. Results: Postoperative chemotherapy was initiated median 19 days after surgery. Total of 238 cycles were administered and median follow-up was 602 days. The median disease-free survival time was 728 days (95% CI, 411∼1045) and 2-year overall survival was 77%. Relapses were reported in 18 (45%) of the patients : Two of 9 patients relapsed in stage IIIA (22.2%), seven of 12 patients relapsed in stage IIIB (58.3%) and nine of 17 patients relapsed in stage IV (52.9%). They were all distant relapsed. Eight patients died. 7 patients died as a result of cancer progression and 1 patient suicided while receiving palliative chemotheraphy for cancer relapse. The grade 3∼4 toxicity of neutropenia 8.4% and anemia 0.4%, neutropenic fever 0.4% were observed. Conclusions: Postoperative LV5FU2 adjuvant chemotherapy is effective and tolerable for the patients with curative resected, advanced gastric cancer.

No significant financial relationships to disclose.

Leptomeningeal carcinomatosis of gastric cancer: Multicenter retrospective analysis of 54 cases

e15658

Background: Leptomeningeal carcinomatosis occurs in approximately 5% of patients with cancer. The most common cancers involving the leptomeninges are breast and lung cancer. However, gastric adenocarcinoma has been rarely reported with leptomeningeal carcinomatosis (LMC). Methods: We analyzed 54 cases of cytological confirmed gastric LMC at 4 institutions from 1994 to 2007. Results: Male to female ratio was 1.5:1. Median age of these patients was 49 years. The majority of patients had advanced disease at the initial diagnosis of gastric cancer. The clinical or pathologic TNM stages of the primary gastric cancer were IV in 38 patients (70%). The median interval from the diagnosis of the primary malignancy to the diagnosis of LMC was 6.3 months (range, 0 - 73.1 months). Of the initial endoscopic finding available 45 patients, Bormann type III and IV were 23 (51%) and 15 (33%) patients, respectively. Headache (85%) and nausea/vomiting (58%) were most common presenting symptoms of LMC. The intrathecal (IT) chemotherapy was administered to 36 patients - mainly with methotraxate alone (59%) or combination with ara- C/hydrocortisone (41%). Median IT treatment number was 7 (range, 1–18). Concomitant radiotherapy or chemotherapy was done in 25 patients and 10 patients, respectively. 17 patients (46%) were achieved cytological negative conversion. Median OS duration from diagnosis of LMC was 6.7 weeks (95% CI; 4.3–9.1 weeks). Clinically, initial advanced stage was predictive value of poor prognosis (P=0.009). But, Cytology negative conversion was predictive value of relatively longer survival duration (P=0.005). And, not only IT chemotherapy but also intravenous chemotherapy had been shown improvement of survival duration (P=0.010, P=0.005, respectively). Conclusions: Although gastric LMC has dismal prognosis, IT and IV chemotherapy could be help to extend survival duration of gastric LMC.

No significant financial relationships to disclose.

Modeling photocurrent transients in organic solar cells

We investigate the transient photocurrents of organic photovoltaic devices in response to a sharp turn-on of illumination, by numerical modeling of the drift-diffusion equations. We show that the photocurrent turn-on dynamics are determined not only by the transport dynamics of free charges, but also by the time required for the population of geminate charge pairs to reach its steady-state value. The dissociation probability of a geminate charge pair is found to be a key parameter in determining the device performance, not only by controlling the efficiency at low intensities, but also in determining the fate of charge pairs formed by bimolecular recombination at high intensities. Bimolecular recombination is shown to reduce the turn-on time at high intensities, since the typical distance traveled by a charge pair is reduced.

DSM-IV pathological gambling in the National Comorbidity Survey Replication

BACKGROUND

Little is known about the prevalence or correlates of DSM-IV pathological gambling (PG).

METHOD

Data from the US National Comorbidity Survey Replication (NCS-R), a nationally representative US household survey, were used to assess lifetime gambling symptoms and PG along with other DSM-IV disorders. Age of onset (AOO) of each lifetime disorder was assessed retrospectively. AOO reports were used to study associations between temporally primary disorders and the subsequent risk of secondary disorders.

RESULTS

Most respondents (78.4%) reported lifetime gambling. Lifetime problem gambling (at least one Criterion A symptom of PG) (2.3%) and PG (0.6%) were much less common. PG was significantly associated with being young, male, and Non-Hispanic Black. People with PG reported first gambling significantly earlier than non-problem gamblers (mean age 16.7 v. 23.9 years, z=12.7, p<0.001), with gambling problems typically beginning during the mid-20s and persisting for an average of 9.4 years. During this time the largest annual gambling losses averaged US$4800. Onset and persistence of PG were predicted by a variety of prior DSM-IV anxiety, mood, impulse-control and substance use disorders. PG also predicted the subsequent onset of generalized anxiety disorder, post-traumatic stress disorder (PTSD) and substance dependence. Although none of the NCS-R respondents with PG ever received treatment for gambling problems, 49.0% were treated at some time for other mental disorders.

CONCLUSIONS

DSM-IV PG is a comparatively rare, seriously impairing, and undertreated disorder whose symptoms typically start during early adulthood and is frequently secondary to other mental or substance disorders that are associated with both PG onset and persistence.

Combination chemotherapy with irinotecan and cisplatin in elderly patients (≥65 years) with extensive-disease small-cell lung cancer

18135

Background: Combination chemotherapy with irinotecan and cisplatin is one of the standard treatments for patients with small-cell lung cancer (SCLC). In elderly patients, however, its efficacy and toxicity has not been well documented. In this Phase II study, we assessed the efficacy and toxicity of combination chemotherapy with irinotecan and cisplatin and examined whether advanced age compromises it in elderly patients with previously untreated extensive-disease small-cell lung cancer (ED-SCLC). Methods: In this study, 43 previously untreated elderly patients (65 years or older) with ED-SCLC were given combination chemotherapy consisting of irinotecan 60mg/m2 on days 1, 8 and 15 and cisplatin 60mg/m2 on days 1. The treatment was repeated every four weeks until patients completed the maximum six cycles. Results: Patients consisted of 34 men and 9 women, whose median age was 70 years (range 65 - 81 years). A complete response and a partial response were observed in 23.3% (10/43) and 58.1% (25/43), respectively. The overall response rate was 81.4% (95% C.I; 69.7 - 93.0%). The overall median survival was 10.3 months (range 7.8 - 12.7 months). The 1-year and 2- year survival rates were 31.8% and 3.4%, respectively. The median progression-free survival was 8.32 months (range 6.8 - 9.8 months). Major toxicities included neutropenia (grade 3 to 4, 55.9%), leukopenia (grade 3 to 4, 46.5%), infection (grade 3 to 4, 37.3%) and diarrhea (grade 3 to 4, 30.3%). Incidence of febrile neutropenia was significantly higher in patients with ECOG performance status 2 compared with ECOG performance 1 (70.7% vs. 5.2%; p < 0.001). There were two treatment related deaths in patients ECOG performance status 2. Conclusions: Our results indicate that combination chemotherapy with irinotecan and cisplatin is an effective treatment for elderly patients with ED-SCLC. However, physicians should be aware of the mortality and morbidity due to myelosuppression following this treatment in elderly ED-SCLC patients with ECOG performance status 2.

No significant financial relationships to disclose.

Irinotecan monotherapy as second-line treatment in advanced pancreatic cancer

15111

Background: The aim of this phase II study was to determine whether second line therapy with single agent irinotecan could provide any clinical benefit in patients with gemcitabine- pretreated advanced pancreatic cancer. Methods: From January 2004 to October 2006, patients with advanced pancreatic cancer previously treated with gemcitabine alone or combination were treated with single agent irinotecan(150 mg/m2, biweekly), until unacceptable toxicity or disease progression. Primary endpoint was response rate with single stage design. Results: Twenty-eight patients were enrolled(22 male, 6 female, median age : 54.5 years (39–76)). Nine patients are still alive and 3 remain on therapy with stable disease. The median number of cycles was 3.5(1–12). Twenty-four patients were assessable for toxicity and 21 for response. The most common toxicities was diarrhea (grade 3, 12.5%). Grade 3 neutropenia in 1 patient was observed. Other hematological and non-hematological toxicities were mild and manageable. Partial responses were observed in 3 patients (3/21, 14%). An additional 9 patients (9/21, 43%) had stable disease as their best response. 12 patients have progressed with a median time-to-progression of 4.0 months. Conclusions: Single-agent irinotecan was tolerated with manageable toxicity, offering encouraging activity as second-line treatment of patients with advanced pancreatic cancer, refractory to gemcitabine.

No significant financial relationships to disclose.

Clinical implication of distinction from clinical features and treatment outcome of malignant lymphoma in Korean childhood and young adult

18534

Background: The Clinicopathologic features of malignant lymphomas vary to geography and differ to age. The goal of this study was to find the implication of distinction from biology, clinical features and treatment outcome of malignant lymphoma in childhood and young adult. Methods: We analysed the clinical features including age, gender, histologic type, and treatment outcome of 294 children and young adults during 13-year period (from May 1993 to November 2005) in Samsung medical center and compared our study to all age group and western childhood and adolescence group on clinical features or treatment outcome in malignant lymphoma. Results: Median age at diagnosis was 20.7 years (range: 0.1–30.1 years). Male to female ratio was 1.37:1, Of 294 cases, there were 248 cases of non-hodgkin’s lymphoma (NHL) (84.3%) and 44 cases of hodgkin’s disease (HD) (15%). This rate was significantly different to rate of all age group (HD= 5.3%) (p=0.001). Of 248 cases of non-hodgkin’s lymphoma, 134 cases (54.0%) were B-lineage and 113 cases (45.6%) were T- or NK-cell lineage. Our study group had higher rates of T- or NK-cell NHL compared to all age group (p=0.001) and western group (p=0.001). Among 248 cases of NHL, the most common histologic type was diffuse large cell lymphoma (DLBL) in our study group. Burkitt’s lymphoma (BL) was the most common histologic types in Western study group. 5-year survival rate (5YSR) was 80.4% and was superior for BL and was inferior for NK/T cell lymphoma. However male T-LBL patients had better outcome in western study group. NHL and T-cell NHL had significantly worse outcomes than HD and B-cell NHL (p=0.049, 0.001, respectively). Comparing age-groups 0–10, 10–20 and 20–30, 5YSR was inferior for the oldest patients only in NHL-, T-cell NHL- and T-cell LBL-groups. Conclusions: Our study suggested environmental and genetic factor was associated with the development of malignant lymphoma.

No significant financial relationships to disclose.

Comparison of the epidermal growth factor receptor gene mutation in matched primary tumor and lymph node metastasis of non-small cell lung cancer

7614

Background: Mutations in epidermal growth factor receptor (EGFR) are considered as a strong predictive marker to EGFR tyrosine kinase inhibitors (TKIs) in non-small-cell lung cancer (NSCLC). Recent studies suggested EGFR status may change between primary NSCLC and corresponding metastatic site. However, it has not fully been evaluated whether EGFR mutation differs in metastases compared to primary NSCLC. Methods: In total, 128 tumor samples from 64 NSCLC patients were investigated comparing matched 64 primary tumors, and 64 lymph node metastases. The epidermal growth factor receptor mutation status was analyzed by a direct sequencing method (exons 18–21 in EGFR) on tumor samples of primary NSCLC and corresponding lymph node metastasis. Results: In 17.2% of patents (11/64), EGFR mutation was identified in either primary NSCLC or metastasis by DNA sequencing. Six (54.5%) out of eleven cases showed discordance of EGFR mutation in the primary tumor/metastasis site. Two cases showed EGFR mutation in the metastasis but not in the primary tumor, while, in four cases, EGFR mutation was detected in the primary tumor but not in the metastasis site. The majority of discordance of EGFR mutations was identified in exon 19 (83.3%, 5/6). The median overall survival (OS) was 17.7 months (95% confidence interval, 9.4–20.0). Median OS was not varied by the discordance of EGFR mutation status between primary NSCLC and corresponding metastatic site. Conclusions: The status of EGFR mutation in primary NSCLC and that in corresponding metastasis site varied in considerable cases by DNA sequencing. Whether the status of EGFR mutation changes during the process of metastasis remains to be evaluated. Future study to evaluate the correlation of tumour response to TKIs and the discordance of the EGFR mutation status is warranted.

No significant financial relationships to disclose.

ICA and water in Korea--overview

The natural water quality in Korea has improved significantly in the last 20 years since major collective national initiatives were implemented by governmental agencies, non-governmental organizations, and professionals among many others. Recently instrumentation, control, and automation (ICA) technology has become one of the most important technologies for carrying out this task. Korea has become especially well known with a strong reputation for information technology and international business with commercial products like semi-conductors, computers, mobile phones, computer games, and other electronic products. In this paper the background of Korean water quality is reviewed and several of the most significant national projects related to ICA are discussed. The major projects may include the Automatic Monitoring Network of River Water Quality and the Integrated Management System of Wastewater Treatment Plants in Upper Basin Area of Multi-purpose Dams.

Identification of genes in thyrocytes regulated by unfolded protein response by using disulfide bond reducing agent of dithiothreitol

Disulfide bonds are formed between the sulfhydryl groups in two cysteine residues of a protein. The formation of these bonds is necessary for the proper folding of a protein into its active three-dimensional form. In this study, the genes associated with disulfide bond formation of proteins from the rat thyroid cell line, FRTL-5 cell, were investigated using disulfide bond reducing agent of dithiothreitol (DTT), which prevented disulfide formation of newly synthesized proteins. The expression of six genes, they being the cAMP phosphodiesterase 7A1, neuronal cell death inducible putative kinase (NIPK), cytosolic LIM protein (Ajuba), Eker, early growth response 1 and the ferritin heavy chain, was specifically enhanced under both reductive conditions and various endoplasmic reticulum (ER) stresses inducing drugs such as Brefeldin A (BFA), calcium ionophore A23187 (A23187) and tunicamycin. These results suggest that a suitable redox environment is necessary for the correct disulfide bond conformation in thyrocytes in a complex system.

Arabidopsis dynamin-like 2 that binds specifically to phosphatidylinositol 4-phosphate assembles into a high-molecular weight complex in vivo and in vitro

Arabadopsis dynamin-like (ADL) 2, a member of the high-molecular weight (M(r)) dynamin family found in Arabidopsis, has been shown to be targeted to the plastid. In the chloroplast, most of the ADL2 was present in the fraction containing the envelope membranes when analyzed by suborganellar fractionation. Sucrose gradient and gel filtration experiments showed that when associated with membranes, ADL2 existed as a high-M(r) complex, whereas the soluble form existed as a monomer. The recombinant ADL2 expressed in Escherichia coli was present as a high-M(r) form and showed higher GTPase activity at a low NaCl concentration, whereas ADL2 existed as a low-M(r) form with a low level of GTPase activity at a high NaCl concentration. Electron microscopy studies revealed that the purified recombinant ADL2 formed spiral-coiled structures or rings. In the presence of guanosine-5'-O-(3-thio)triphosphate, these structures were transformed into a long rod structure. In contrast, in the presence of GDP, these structures disassembled into oligomers that were shown to be tetramer with 4-fold symmetry. Finally, a lipid-binding assay revealed that recombinant ADL2 purified from E. coli bound specifically to phosphatidylinositol 4-phosphate. Together, these results demonstrated that the biochemical properties of ADL2 were very similar to those of dynamin and other related proteins. Based on this similarity, we propose that ADL2 may be involved in vesicle formation at the chloroplast envelope membrane.

Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo

Certain small outer envelope membrane proteins of chloroplasts are encoded by the nuclear genome without a cleavable N-terminal transit peptide. We investigated in vivo the targeting mechanism of AtOEP7, an Arabidopsis homolog of the small outer envelope membrane protein. AtOEP7 was expressed as a fusion protein with the green fluorescent protein (GFP) either transiently in protoplasts or stably in transgenic plants. In either case, fluorescence microscopy of transformed cells and protein gel blot analysis of fractionated proteins confirmed that the AtOEP7:GFP fusion protein was targeted to the chloroplast outer envelope membrane. In vivo targeting experiments revealed that two regions, the transmembrane domain (TMD) and its C-terminal neighboring seven-amino acid region, were necessary and sufficient for targeting to the chloroplast outer membrane. Substitution of aspartic acid or lysine residues with glycine residues or scrambling of the amino acid sequence of the seven-amino acid region caused mistargeting to the plasma membrane. Although the amino acid sequence of the TMD is not important for targeting, amino acid residues with large side chains inhibited targeting to the chloroplasts and resulted in the formation of large aggregates in the protoplasts. In addition, introduction of a proline residue within the TMD resulted in inhibition of targeting. Finally, a fusion protein, AtOEP7:NLS:GFP, was targeted efficiently to the chloroplast envelope membranes despite the presence of a nuclear localization signal. On the basis of these results, we conclude that the seven-amino acid region and the TMD are determinants for targeting to the chloroplast outer envelope membrane. The seven-amino acid region plays a critical role in AtOEP7 evading the endomembrane system and entering the chloroplast pathway, and the TMD plays critical roles in migration to the chloroplasts and/or subsequent insertion into the membrane.

Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo

Certain small outer envelope membrane proteins of chloroplasts are encoded by the nuclear genome without a cleavable N-terminal transit peptide. We investigated in vivo the targeting mechanism of AtOEP7, an Arabidopsis homolog of the small outer envelope membrane protein. AtOEP7 was expressed as a fusion protein with the green fluorescent protein (GFP) either transiently in protoplasts or stably in transgenic plants. In either case, fluorescence microscopy of transformed cells and protein gel blot analysis of fractionated proteins confirmed that the AtOEP7:GFP fusion protein was targeted to the chloroplast outer envelope membrane. In vivo targeting experiments revealed that two regions, the transmembrane domain (TMD) and its C-terminal neighboring seven-amino acid region, were necessary and sufficient for targeting to the chloroplast outer membrane. Substitution of aspartic acid or lysine residues with glycine residues or scrambling of the amino acid sequence of the seven-amino acid region caused mistargeting to the plasma membrane. Although the amino acid sequence of the TMD is not important for targeting, amino acid residues with large side chains inhibited targeting to the chloroplasts and resulted in the formation of large aggregates in the protoplasts. In addition, introduction of a proline residue within the TMD resulted in inhibition of targeting. Finally, a fusion protein, AtOEP7:NLS:GFP, was targeted efficiently to the chloroplast envelope membranes despite the presence of a nuclear localization signal. On the basis of these results, we conclude that the seven-amino acid region and the TMD are determinants for targeting to the chloroplast outer envelope membrane. The seven-amino acid region plays a critical role in AtOEP7 evading the endomembrane system and entering the chloroplast pathway, and the TMD plays critical roles in migration to the chloroplasts and/or subsequent insertion into the membrane.

Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo

Certain small outer envelope membrane proteins of chloroplasts are encoded by the nuclear genome without a cleavable N-terminal transit peptide. We investigated in vivo the targeting mechanism of AtOEP7, an Arabidopsis homolog of the small outer envelope membrane protein. AtOEP7 was expressed as a fusion protein with the green fluorescent protein (GFP) either transiently in protoplasts or stably in transgenic plants. In either case, fluorescence microscopy of transformed cells and protein gel blot analysis of fractionated proteins confirmed that the AtOEP7:GFP fusion protein was targeted to the chloroplast outer envelope membrane. In vivo targeting experiments revealed that two regions, the transmembrane domain (TMD) and its C-terminal neighboring seven-amino acid region, were necessary and sufficient for targeting to the chloroplast outer membrane. Substitution of aspartic acid or lysine residues with glycine residues or scrambling of the amino acid sequence of the seven-amino acid region caused mistargeting to the plasma membrane. Although the amino acid sequence of the TMD is not important for targeting, amino acid residues with large side chains inhibited targeting to the chloroplasts and resulted in the formation of large aggregates in the protoplasts. In addition, introduction of a proline residue within the TMD resulted in inhibition of targeting. Finally, a fusion protein, AtOEP7:NLS:GFP, was targeted efficiently to the chloroplast envelope membranes despite the presence of a nuclear localization signal. On the basis of these results, we conclude that the seven-amino acid region and the TMD are determinants for targeting to the chloroplast outer envelope membrane. The seven-amino acid region plays a critical role in AtOEP7 evading the endomembrane system and entering the chloroplast pathway, and the TMD plays critical roles in migration to the chloroplasts and/or subsequent insertion into the membrane.

Two-component circuitry in Arabidopsis cytokinin signal transduction

Cytokinins are essential plant hormones that are involved in shoot meristem and leaf formation, cell division, chloroplast biogenesis and senescence. Although hybrid histidine protein kinases have been implicated in cytokinin perception in Arabidopsis, the action of histidine protein kinase receptors and the downstream signalling pathway has not been elucidated to date. Here we identify a eukaryotic two-component signalling circuit that initiates cytokinin signalling through distinct hybrid histidine protein kinase activities at the plasma membrane. Histidine phosphotransmitters act as signalling shuttles between the cytoplasm and nucleus in a cytokinin-dependent manner. The short signalling circuit reaches the nuclear target genes by enabling nuclear response regulators ARR1, ARR2 and ARR10 as transcription activators. The cytokinin-inducible ARR4, ARR5, ARR6 and ARR7 genes encode transcription repressors that mediate a negative feedback loop in cytokinin signalling. Ectopic expression in transgenic Arabidopsis of ARR2, the rate-limiting factor in the response to cytokinin, is sufficient to mimic cytokinin in promoting shoot meristem proliferation and leaf differentiation, and in delaying leaf senescence.

Reductive dechlorination of tetrachloroethylene in soils by Fe(II)-based degradative solidification/stabilization

Fe(II)-based degradative solidification/stabilization (DS/S) is a modification of conventional solidification/stabilization (S/S) that uses Fe(II) as a reducing agent for chlorinated organics while immobilizing inorganic contaminants. Feasibility of the Fe(II)-based DS/S technology in treating soils contaminated with tetrachloroethylene (PCE) was tested in this study. The results of the PCE degradation experiments conducted in the presence of a humic acid suggest that natural organic matter would not significantly interfere with the degradative reaction by the Fe(II)-containing reactive species in DS/S systems. Solid-phase degradation experiments showed that the DS/S technology could effectively treat PCE in soils without substantial production of chlorinated intermediates. A pseudo-first-order rate law reasonably described degradation kinetics. The half-lives of PCE ranged from 13 to 335 days, which are within time spans allowable for typical in-situ DS/S application. Trichloroethylene (TCE) was the only chlorinated product observed in the solid-phase experiments, and its presence was generally transitory with the amount being less than 7% of the initial amount of PCE on a molar basis. A surface reaction appears to control observed PCE degradation kinetics rather than mass transfer to the reactive surface.

Diversity and regulation of plant Ca2+ pumps: insights from expression in yeast

The spatial and temporal regulation of calcium concentration in plant cells depends on the coordinate activities of channels and active transporters located on different organelles and membranes. Several Ca2+ pumps have been identified and characterized by functional expression of plant genes in a yeast mutant (K616). This expression system has opened the way to a genetic and biochemical characterization of the regulatory and catalytic features of diverse Ca2+ pumps. Plant Ca(2+)-ATPases fall into two major types: AtECA1 represents one of four or more members of the type IIA (ER-type) Ca(2+)-ATPases in Arabidopsis, and AtACA2 is one of seven or more members of the type IIB (PM-type) Ca(2+)-ATPases that are regulated by a novel amino terminal domain. Type IIB pumps are widely distributed on membranes, including the PM (plasma membrane), vacuole, and ER (endoplasmic reticulum). The regulatory domain serves multiple functions, including autoinhibition, calmodulin binding, and sites for modification by phosphorylation. This domain, however, is considerably diverse among several type IIB ATPases, suggesting that the pumps are differentially regulated. Understanding of Ca2+ transporters at the molecular level is providing insights into their roles in signaling networks and in regulating fundamental processes of cell biology.

Constitutive over-expression of AtGSK1 induces NaCl stress responses in the absence of NaCl stress and results in enhanced NaCl tolerance in Arabidopsis

GSK3/shaggy-like protein kinases have been shown to play diverse roles in development and signal transduction pathways in various organisms. An Arabidopsis homologue of GSK3/shaggy-like kinase, AtGSK1, has been shown to be involved in NaCl stress responses. In order to further clarify the role of AtGSK1 in NaCl stress responses in plants, we generated transgenic Arabidopsis plants that over-expressed AtGSK1 mRNA. These plants showed enhanced resistance to NaCl stress when assayed either as whole plants or by measurement of root growth on NaCl plates. In addition, AtGSK1 transgenic plants in the absence of NaCl stress showed phenotypic changes, such as accumulation of anthocyanin, that were similar to those observed in wild-type plants under NaCl stress. Transgenic plants accumulated 30-50% more Na+ than did wild-type plants when subjected to NaCl stress, and Ca2+ content was increased by 15-30% in the transgenic plants regardless of the NaCl stress level. Northern blotting revealed that AtGSK1 over-expression induced expression of the NaCl stress-responsive genes AtCP1, RD29A and CHS1 in the absence of NaCl stress. In addition, AtCBL1 and AtCP1 were super-induced in the NaCl-stressed transgenic plants. Taken together, these results suggest that AtGSK1 is involved in the signal transduction pathway(s) of NaCl stress responses in Arabidopsis.

A new dynamin-like protein, ADL6, is involved in trafficking from the trans-Golgi network to the central vacuole in Arabidopsis

Dynamin, a high-molecular-weight GTPase, plays a critical role in vesicle formation at the plasma membrane during endocytosis in animal cells. Here we report the identification of a new dynamin homolog in Arabidopsis named Arabidopsis dynamin-like 6 (ADL6). ADL6 is quite similar to dynamin I in its structural organization: a conserved GTPase domain at the N terminus, a pleckstrin homology domain at the center, and a Pro-rich motif at the C terminus. In the cell, a majority of ADL6 is associated with membranes. Immunohistochemistry and in vivo targeting experiments revealed that ADL6 is localized to the Golgi apparatus. Expression of the dominant negative mutant ADL6[K51E] in Arabidopsis protoplasts inhibited trafficking of cargo proteins destined for the lytic vacuole and caused them to accumulate at the trans-Golgi network. In contrast, expression of ADL6[K51E] did not affect trafficking of a cargo protein, H(+)-ATPase:green fluorescent protein, destined for the plasma membrane. These results suggest that ADL6 is involved in vesicle formation for vacuolar trafficking at the trans-Golgi network but not for trafficking to the plasma membrane in plant cells.

A new dynamin-like protein, ADL6, is involved in trafficking from the trans-Golgi network to the central vacuole in Arabidopsis

Dynamin, a high-molecular-weight GTPase, plays a critical role in vesicle formation at the plasma membrane during endocytosis in animal cells. Here we report the identification of a new dynamin homolog in Arabidopsis named Arabidopsis dynamin-like 6 (ADL6). ADL6 is quite similar to dynamin I in its structural organization: a conserved GTPase domain at the N terminus, a pleckstrin homology domain at the center, and a Pro-rich motif at the C terminus. In the cell, a majority of ADL6 is associated with membranes. Immunohistochemistry and in vivo targeting experiments revealed that ADL6 is localized to the Golgi apparatus. Expression of the dominant negative mutant ADL6[K51E] in Arabidopsis protoplasts inhibited trafficking of cargo proteins destined for the lytic vacuole and caused them to accumulate at the trans-Golgi network. In contrast, expression of ADL6[K51E] did not affect trafficking of a cargo protein, H(+)-ATPase:green fluorescent protein, destined for the plasma membrane. These results suggest that ADL6 is involved in vesicle formation for vacuolar trafficking at the trans-Golgi network but not for trafficking to the plasma membrane in plant cells.