Increasing small conductance Ca2+-activated potassium channel activity reverses ischemia-induced impairment of long-term potentiation

Global cerebral ischemia following cardiac arrest and cardiopulmonary resuscitation (CA/CPR) causes injury to hippocampal CA1 pyramidal neurons and impairs cognition. Small conductance Ca(2+)-activated potassium channels type 2 (SK2), expressed in CA1 pyramidal neurons, have been implicated as potential protective targets. Here we showed that, in mice, hippocampal long-term potentiation (LTP) was impaired as early as 3 h after recovery from CA/CPR and LTP remained impaired for at least 30 days. Treatment with the SK2 channel agonist 1-Ethyl-2-benzimidazolinone (1-EBIO) at 30 min after CA provided sustained protection from plasticity deficits, with LTP being maintained at control levels at 30 days after recovery from CA/CPR. Minimal changes in glutamate release probability were observed at delayed times after CA/CPR, implicating post-synaptic mechanisms. Real-time quantitative reverse transcriptase-polymerase chain reaction indicated that CA/CPR did not cause a loss of N-methyl-D-aspartate (NMDA) receptor mRNA at 7 or 30 days after CA/CPR. Similarly, no change in synaptic NMDA receptor protein levels was observed at 7 or 30 days after CA/CPR. Further, patch-clamp experiments demonstrated no change in functional synaptic NMDA receptors at 7 or 30 days after CA/CPR. Electrophysiology recordings showed that synaptic SK channel activity was reduced for the duration of experiments performed (up to 30 days) and that, surprisingly, treatment with 1-EBIO did not prevent the CA/CPR-induced loss of synaptic SK channel function. We concluded that CA/CPR caused alterations in post-synaptic signaling that were prevented by treatment with the SK2 agonist 1-EBIO, indicating that activators of SK2 channels may be useful therapeutic agents to prevent ischemic injury and cognitive impairments.

Electroconvulsive seizures enhance autophagy signaling in rat hippocampus

The putative antidepressive mechanisms of a series of electroconvulsive seizures (ECS) are the following: 1) downregulation of monoaminergic receptor expression in several brain regions, 2) upregulation of the expression of brain-derived neurotrophic factor (BDNF), and 3) increased neurogenesis in the hippocampus. In this study, we used Western blot techniques to present another mechanism in which ECS enhances the autophagy signaling that is involved in the machinery related to synaptic and neural plasticity. Antibodies for conjugated Atg5-Atg12 (58kD) and cleaved light chain protein 3-II (LC3-II; 14 kD) were used to detect autophagy signals. An antibody for cleaved caspase-3 (17 kD) was used to detect alterations in apoptotic signals. Mature BDNF (14kD) expression in the hippocampus was evaluated in order to qualify the effectiveness of the ECS or stress-loading treatment. While significantly increased autophagy signals and no increases in apoptotic signals were detected in the ECS-treated rat hippocampus, the reverse (increased apoptotic signals and no altered autophagy signals) was observed in stressed rat hippocampus. No neuronal cell loss but new mossy fiber sprouting has been reported to accompany multiple ECS treatments, and recent studies have revealed that autophagy processes regulate the number of specific neurotransmitter receptors and the plasticity of synaptic components. The present study illustrated the neuroplastic and neurotrophic profiles of ECS and the neurotoxic impact of severe stress loading on hippocampal regions. This is the first report to demonstrate increased autophagy signals in ECS-treated rat hippocampus and no alterations in autophagy signals in stress-loaded rat hippocampus.

ASC amino-acid transporter 2 (ASCT2) as a novel prognostic marker in non-small cell lung cancer

Background:

ASC amino-acid transporter 2 (ASCT2) is a major glutamine transporter that has an essential role in tumour growth and progression. Although ASCT2 is highly expressed in various cancer cells, the clinicopathological significance of its expression in non-small cell lung cancer (NSCLC) remains unclear.

Methods:

One hundred and four patients with surgically resected NSCLC were evaluated as one institutional cohort. Tumour sections were stained by immunohistochemistry (IHC) for ASCT2, Ki-67, phospho-mTOR (mammalian target of rapamycin), and CD34 to assess the microvessel density. Two hundred and four patients with NSCLC were also validated by IHC from an independent cohort.

Results:

ASC amino-acid transporter 2 was expressed in 66% of patients, and was closely correlated with disease stage, lymphatic permeation, vascular invasion, CD98, cell proliferation, angiogenesis, and mTOR phosphorylation, particularly in patients with adenocarcinoma (AC). Moreover, two independent cohorts confirmed that ASCT2 was an independent marker for poor outcome in AC patients.

Conclusions:

ASC amino-acid transporter 2 expression has a crucial role in the metastasis of pulmonary AC, and is a potential molecular marker for predicting poor prognosis after surgery.

Clinicopathological and prognostic significance of interleukin-8 expression and its relationship to KRAS mutation in lung adenocarcinoma

Background:

On the basis of our recent findings of oncogenic KRAS-induced interleukin-8 (IL-8) overexpression in non-small cell lung cancer, we assessed the clinicopathological and prognostic significances of IL-8 expression and its relationship to KRAS mutations in lung adenocarcinomas.

Methods:

IL-8 expression was examined by quantitative RT–PCR using 136 of surgical specimens from lung adenocarcinoma patients. The association between IL-8 expression, clinicopathological features, KRAS or EGFR mutation status and survival was analysed.

Results:

IL-8 was highly expressed in tumours from elderly patients or smokers and in tumours with pleural involvement or vascular invasion. In a non-smokers' subgroup, IL-8 level positively correlated with age. IL-8 was highly expressed in tumours with KRAS mutations compared with those with EGFR mutations or wild-type EGFR/KRAS. Lung adenocarcinoma patients with high IL-8 showed significantly shorter disease-free survival (DFS) and overall survival (OS) than those with low IL8. DFS and OS were significantly shorter in the patients with mutant KRAS/high IL-8 than in those with wild-type KRAS/low IL-8. Cox regression analyses demonstrated that elevated IL-8 expression correlated with unfavourable prognosis.

Conclusions:

Our findings suggest that IL-8 expression is associated with certain clinicopathological features including age and is a potent prognostic marker in lung adenocarcinoma, especially in oncogenic KRAS-driven adenocarcinoma.

[Involvement of autophagy in neuronal plasticity by psychiatric treatment]

Recently we have reported increased hippocampal autophagy signaling after multiple electroconvulsive seizure treatments. The involvement of autophagy process in the neuronal plasticity of synapses and dendrites and in the regulation of the number of specific receptors has been reported in basic studies using C. elegans, drosophila, and cultured neurons. The importance of the autophagy process in neuronal plasticity that supports the stress resilience should be further studied.

Psychological effects of disaster relief activities on Japan ground self-defense force personnel following the 2011 great east Japan earthquake

OBJECTIVE

Disaster relief workers are potentially exposed to severe stressors on the job, resulting in a variety of psychological responses. This study aims to clarify the psychological effects of disaster relief activities on Japan Ground Self-Defense Force (JGSDF) personnel following the 2011 Great East Japan Earthquake.

METHOD

A self-report questionnaire was administered to 606 JGSDF personnel one month after completing the disaster relief mission. Posttraumatic stress responses and general psychological distress were assessed using the Impact of Event Scale-Revised (IES-R) and the K10 scales. Associations between outcome variables and independent variables (age, gender, military rank, length of deployment, and exposure to dead bodies) were measured with univariate analyses and subsequent multiple logistic regression analyses.

RESULTS

The mean (± SD) IES-R score was 6.2 (± 8.1), and the mean K10 score was 12.8 (± 4.4). In the univariate analyses, exposure to dead bodies and age were identified as significant factors for IES-R and K10 scores, (p < 0.01). However, the multiple logistic regression analyses did not reveal any significant factors although body handlers' exposure approached significance for IES-R.

CONCLUSIONS

The subjects reported very low psychological responses despite the severe nature of their disaster relief activities. Several factors may account for the low levels of psychological distress and posttraumatic symptoms observed in this study.

Neurological deterioration due to missed thoracic spinal stenosis after decompressive lumbar surgery

There have been a few reports of patients with a combination of lumbar and thoracic spinal stenosis. We describe six patients who suffered unexpected acute neurological deterioration at a mean of 7.8 days (6 to 10) after lumbar decompressive surgery. Five had progressive weakness and one had recurrent pain in the lower limbs. There was incomplete recovery following subsequent thoracic decompressive surgery.

The neurological presentation can be confusing. Patients with compressive myelopathy due to lower thoracic lesions, especially epiconus lesions (T10 to T12/L1 disc level), present with similar symptoms to those with lumbar radiculopathy or cauda equina lesions. Despite the rarity of this condition we advise that patients who undergo lumbar decompressive surgery for stenosis should have sagittal whole spine MRI studies pre-operatively to exclude proximal neurological compression.

Cite this article: Bone Joint J 2013;95-B:1388–91.

Effect of Hexamethylene Diisocyanate as Compatibilizer on the Mechanical Properties of Banana Fiber/Poly(butylene succinate) Composites

We prepared banana fiber (BF)/poly(butylene succinate) (PBS) composites using hexamethylene diisocyanate (HDI) as a compatibilizer. BF was treated with NaOH aqueous solution (BF-A). Both BF/PBS/HDI and BF-A/PBS/HDI composites were made by applying a batch type twin-kneader at 130°C. Dumbbell specimens were prepared by an injection molding machine at 130°C. Effect of concentration of NaOH aq on tensile strength and impact strength, effect of amount of HDI on tensile strength and Izod impact strength, and effect of mixing time on tensile strength and Izod impact strength of BF/PBS/HDI and BF-A/PBS/HDI composites were studied. When contents of HDI in composites were increased, tensile strength increased. In addition, when mixing times were increased, tensile strength increased. Although the mechanical properties of PBS were first degraded with the addition of BF, alkaline treatment to BF and the addition of HDI improved the mechanical properties. This probably due to the promotion of the adhesion between BF and PBS. The surface morphology of the fracture surfaces of the composites were observed with a scanning electron microscope (SEM). It shows that higher mechanical properties can be expected from compatibilized composites based on BF-As with aliphatic polyesters.

Feasibility trial for adjuvant chemotherapy with docetaxel plus cisplatin followed by single agent long-term administration of S-1 chemotherapy in patients with completely resected non-small cell lung cancer: Thoracic Oncology Research Group Study 0809

BACKGROUND

We conducted a multicentre feasibility study for single agent long-term S-1 chemotherapy following docetaxel plus cisplatin in patients with curatively resected stage II-IIIA non-small cell lung cancer.

METHODS

Patients received three cycles of docetaxel (60 mg m(-2)) plus cisplatin (80 mg m(-2)) and then received S-1 (40 mg m(-2) twice daily) for 14 consecutive days with a 1-week rest for >6 months (maximum, 1 year). The primary end point was feasibility, which was defined as the proportion of patients who completed eight or more cycles of S-1 chemotherapy. If the lower 95% confidence interval (CI) of this proportion was 50% or more, then the treatment was considered as feasible. The sample size was set at 125 patients.

RESULTS

One hundred and thirty-one patients were enrolled, of whom 129 patients were eligible and assessable. In all, 109 patients (84.5%) completed 3 cycles of docetaxel plus cisplatin and 66 patients (51.2%, 95% CI: 42.5-59.8) completed 8 or more cycles of S-1 treatment. Grade 3/4 toxicities during the S-1 chemotherapy included anaemia (7.3%), neutropaenia (3.7%), and anorexia (3.7%).

CONCLUSION

The toxicity level was acceptable, although the results did not meet our criterion for feasibility. Modification of the treatment schedule for S-1 chemotherapy might improve the treatment compliance.