mGluR2/3 mechanisms in primate dorsolateral prefrontal cortex: evidence for both presynaptic and postsynaptic actions.

Cognitive deficits in psychiatric and age-related disorders generally involve dysfunction of the dorsolateral prefrontal cortex (dlPFC), but there are few treatments for these debilitating symptoms. Group II metabotropic glutamate receptors (mGluR2/3), which couple to Gi/Go, have been a focus of therapeutics based on rodent research, where mGluR2/3 have been shown to reduce axonal glutamate release and increase glial glutamate uptake. However, this strategy has had mixed results in patients, and understanding mGluR2/3 mechanisms in primates will help guide therapeutic interventions. The current study examined mGluR2/3 localization and actions in the primate dlPFC layer III circuits underlying working memory, where the persistent firing of 'Delay cells' is mediated by N-methyl-d-aspartate receptors and weakened by cAMP-PKA-potassium channel signaling in dendritic spines. Immunoelectron microscopy identified postsynaptic mGluR2/3 in the spines, in addition to the traditional presynaptic and astrocytic locations. In vivo iontophoretic application of the mGluR2/3 agonists (2R, 4R)-APDC or LY379268 onto dlPFC Delay cells produced an inverted-U effect on working memory representation, with enhanced neuronal firing following low doses of mGluR2/3 agonists. The enhancing effects were reversed by an mGluR2/3 antagonist or by activating cAMP signaling, consistent with mGluR2/3 inhibiting postsynaptic cAMP signaling in spines. Systemic administration of these agonists to monkeys performing a working memory task also produced an inverted-U dose-response, where low doses improved performance but higher doses, similar to clinical trials, had mixed effects. Our data suggest that low doses of mGluR2/3 stimulation may have therapeutic effects through unexpected postsynaptic actions in dlPFC, strengthening synaptic connections and improving cognitive function.

Hospitalization and mortality due to hepatitis A in Taiwan: a 15-year nationwide cohort study.

Hepatitis A virus (HAV) is the most common food-borne hepatitis in the world. The study objectives were (i) to describe the epidemiology of HAV-related hospitalizations during 1997-2011 in Taiwan, (ii) to examine the age effect on the length of stay (LOS) in hospital and (iii) to study the factors associated with death. The hospitalized cases were identified from the Taiwan National Health Insurance Research Database between 1997 and 2011 by ICD-9-CM code of 070.0/070.1. Patient sex, birthday, dates of hospitalization and death were analysed. A total of 3990 HAV-hospitalized cases, males 2467 (62%), were identified. The LOS increased as patients' age increased. The overall mortality rate was 16.8 per 1000 hospitalizations. Males had significantly higher case fatality rate than females (20.7 vs 10.5 per 1000 cases). The adjusted odds ratio (aOR) for death rose by age and increased rapidly over 40 years of age. The aOR and 95% confidence interval [95%CI] for aged 40-59 years and aged over 60 years were 7.89 (1.06-58.98) and 14.88 (2.02-109.40) compared to aged 0-19 years, respectively. Patients with chronic liver disease and cirrhosis had significantly higher risk of death (aOR=1.03 [1.01-1.04]), compared to those without liver disease. However, patients with liver disease, but no cirrhosis did not have higher risk of death (aOR=1.00 [0.99-1.01]). The aOR [95%CI] for LOS >9 day was 3.26 (1.96-5.40) compared to cases with LOS ≤9 days. Male sex, age over 40 years, cirrhotic liver and long LOS are significant factors associated with death in HAV-hospitalized cases.

Overexpression of Aurora-C interferes with the spindle checkpoint by promoting the degradation of Aurora-B.

The chromosomal passenger complex (CPC) plays a pivotal role in controlling accurate chromosome segregation and cytokinesis during cell division. Aurora-B, one of the chromosomal passenger proteins, is important for the mitotic spindle assembly checkpoint (SAC). Previous reports noted that Aurora-C is predominantly expressed in male germ cells and has the same subcellular localization as Aurora-B. Increasing evidence indicates that Aurora-C is overexpressed in many somatic cancers, although its function is uncertain. Our previous study showed that the aberrant expression of Aurora-C increases the tumorigenicity of cancer cells. Here, we demonstrate that overexpressed Aurora-C displaces the centromeric localization of CPCs, including INCENP, survivin, and Aurora-B. When cells were treated with nocodazole to turn on SAC, both the Aurora-B protein stability and kinase activity were affected by overexpressed Aurora-C. As a result, the activation of spindle checkpoint protein, BubR1, and phosphorylation of histone H3 and MCAK were also eliminated in Aurora-C-overexpressing cells. Thus, our results suggest that aberrantly expressed Aurora-C in somatic cancer cells may impair SAC by displacing the centromeric localization of CPCs.

Longitudinal MR imaging study in the prediction of ischemic susceptibility after cerebral hypoperfusion in rats: Influence of aging and hypertension.

Our previous study has shown that aging and hypertension may alter apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) and increase ischemic susceptibility in the non-ischemic rat brain. The present study wishes to further investigate whether aging and hypertension may influence cerebral diffusion/perfusion and increase ischemic susceptibility in the ischemic brain. Brain magnetic resonance (MR) imaging was examined 1day before and 1 and 7days after bilateral common carotid artery occlusion. Young and middle-aged normotensive Wistar-Kyoto rats and young and middle-aged spontaneously hypertensive rats (SHRs) were studied. Infarction occurred mainly in the parietal cortex and was larger in middle-aged SHRs than the other three groups (P<0.05). In pre-operation, ADC was higher and CBF was lower in middle-aged/hypertensive rats than young/normotensive rats (P<0.05). The ADC was higher in the parietal cortex of the rats with infarction at 7days when compared to the rats without infarction [receiver operating characteristic curve (ROC), P=0.001; binary logistic regression (BLR), P=0.006]. However, there was no difference in the hippocampus and thalamus. At day 1 post-operation, CBF reduced and ADC/CBF ratio elevated significantly in the parietal cortex of the rats with infarction when compared to the rats without infarction (CBF: ROC, P=0.002; BLR, P=0.017. ADC/CBF ratio: ROC, P=0.001; BLR, P=0.018). Our results demonstrated that pre-operation ADC and post-operation CBF and ADC/CBF ratio can be used as good MR markers in the prediction of ischemic susceptibility after cerebral hypoperfusion.

Traumatic vertebral artery aneurysm following blunt suboccipital trauma.

Traumatic vertebral artery (VA) injury has been neglected and mistaken to be innocuous. Herein, we present a rare case with a as subarachnoid hemorrhage (SAH) following blunt suboccipital trauma. Initially, it was mistaken as a saccular aneurysm and was just coincident with traumatic SAH. Surgical clipping was performed by our senior neurosurgeon and looked secure. But massive bleeding occurred before complete closure of the dura wound. Opening the wound again, blood gushed out from the junction of the aneurysm and the parent artery. Because preoperative angiography evaluation had revealed good collateral flow from the contralateral VA, the involved segment of VA was trapped. The patient recovered well with uneventful course. Blunt suboccipital trauma may result in traumatic VA injury which may cause catastrophic complications if neglected. The incidence, risk factors, the pathophysiology of traumatic VA aneurysm, and the treatments are reviewed.

Minimally invasive vertebroplasty in the treatment of pain induced by spinal metastatic tumor.

Spinal metastatic tumor is a common problem and represents a challenging problem in oncology practice. Patients with osteolytic metastases often suffer from intractable local and/or radicular pain. Percutaneous vertebroplasty is a minimally invasive, radiologically guided procedure whereby bone cement is injected into structurally weakened vertebrae to provide immediate biomechanical stability. Vertebroplasty is also used to relieve pain by stabilizing metastatically compromised vertebrae that are at risk of pathological burst fracture. In this retrospective study, a total of 57 patients (78 vertebrae) with spinal metastatic tumor were treated with PMMA vertebroplasty. The mean value of the visual analogue scale (VAS) was 8.1 +/- 0.67 preoperatively, and significantly decreased to 3.8 +/- 1.9 (1-8, p < 0.015) one day after vertebroplasty. The mean VAS value 6 months after vertebroplsty was 2.8 +/- 2.0 (p < 0.001). Mean injected bone cement amount in our study is 5.16 +/- 1.6 mL. The complication rate is about 21.8%, bone cement extravasation without neurological deficit is the most common complication. No new or adjacent vertebral fracture has occurred in more than 2 years follow-up. Percutaneous vertebroplasty is a minimally invasive procedure that offers a remarkable advantage of effective and immediate pain relief with few complications.

Distinctive activation patterns in constitutively active and gefitinib-sensitive EGFR mutants.

Mutations in the kinase domain of epidermal growth factor receptor (EGFR) are associated with clinical responsiveness to gefitinib in patients with non-small-cell lung cancers (NSCLC). Recently, we have identified many novel EGFR mutations in NSCLC tissues. In this study, we found that gefitinib could suppress the tyrosine phosphorylation of most EGFR mutants better than the wild-type receptor. However, gefitinib had quite variable growth-suppressive effects on different EGFR mutant-expressing cells. All tested EGFR mutants have high basal phosphorylation at multiple tyrosine residues. Upon EGF stimulation, the mutated EGFRs did not have apparently stronger phosphorylation at tyrosines 845, 992, 1,068, and 1,173 than the wild-type receptor. However, stronger phosphorylation at tyrosine 1,045 was observed in the S768I, L861Q, E709G, and G719S mutants. The E746-A750 deletion mutant was less responsive to EGF than the wild-type and other mutant receptors. The S768I, L861Q, E709G, and G719S mutants were refractory to EGF-induced ubiquitination and had more sustained tyrosine phosphorylation. E709G and G719S also lacked EGF-induced receptor downregulation. Our results indicate that, in addition to sensitivity to gefitinib, EGFR mutations also caused various changes in EGFR's regulatory mechanisms, which may contribute to the constitutive activation of EGFR mutants and oncogenesis in NSCLC.

PALS db: Putative Alternative Splicing database.

PALS db is a collection of Putative Alternative Splicing information from 19 936 human UniGene clusters and 16 615 mouse UniGene clusters. Alternative splicing (AS) sites were predicted by using the longest messenger RNA (mRNA) sequence in each UniGene cluster as the reference sequence. This sequence was aligned with related sequences in UniGene and dbEST to reveal the AS. This information was presented with six features: (i) literature aliases were used to improve the result of a gene name search; (ii) the quality of a prediction can be easily judged from the color-coded similarity and the scaled length of an alignment; (iii) we have clustered those EST sequences that support the same AS site together to enhance the users' confidence on a prediction; (iv) the users can also set up the alignment criteria interactively to recover false negatives; (v) tissue distribution can be displayed by placing the mouse cursor over an alignment; (vi) gene features will be analyzed at foreign sites by submitting the selected mRNA or its encoded protein as a query. Using these features, the users cannot only discover putative AS sites in silico, but also make new observations by combining AS information with tissue distributions or with gene features. PALS db is available at http://palsdb.ym.edu.tw/.

Acetic acid production from fructose by clostridium formicoaceticum immobilized in a fibrous-Bed bioreactor

The fermentation kinetics of acetic acid production from fructose by Clostridium formicoaceticum was studied at pH 7.6 and 37 degreesC. Recycle batch, fed-batch, and continuous fermentations using immobilized cells in a fibrous-bed bioreactor were studied for their potential application in producing acetic acid from fructose, a fermentable sugar commonly found in corn steep liquor and many other food processing wastes. For the immobilized cell fermentation, acetic acid yield from fructose was approximately 1.0 g/g, with a final acetate concentration of approximately 78 g/L and the overall reactor productivity (based on the fibrous bed bioreactor volume) of approximately 0.95 g/(L.h) in the fed-batch fermentation. For a similar fed-batch fermentation with free cells, acetic acid yield was approximately 0.9 g/g, the highest final acetate concentration was approximately 46 g/L, and the overall productivity was approximately 0.12 g/(L.h). In the continuous fermentation with immobilized cells, the reactor productivity decreased from 3.2 to 1. 3 g/(L.h) as retention time increased from 16 to 72 h to reach 100% conversion. Compared to free-cell fermentations, the superior performance of the fibrous-bed bioreactor can be attributed to the high density (>30 g/L) of viable cells immobilized in the fibrous bed. The fermentation product, acetic acid, was found to be a noncompetitive inhibitor to the cells. However, the immobilized cells had a higher maximum production rate (pmax) and a higher value for the inhibition rate constant (Kp) than those for the free cells, suggesting that the immobilized cells in the fibrous-bed bioreactor were less sensitive to acetic acid inhibition than the free cells. This improvement in kinetic behaviors for immobilized cells confirms that the fibrous-bed bioreactor can be used as an effective tool for adapting and screening for acetate-tolerant strains.

Production of amylases from rice by solid-state fermentation in a gas-solid spouted-Bed bioreactor

A gas-solid spouted-bed bioreactor was developed to produce amylases from rice in solid-state fermentation by Aspergillus oryzae. The spouted-bed bioreactor was developed to overcome many of the problems inherent to large-scale solid-state fermentation, including mass- and heat-transfer limitations in the conventional tray reactors and solids-handling difficulties seen in packed-bed bioreactors. The solid-state fermentation results from the tray-type reactor with surface aeration were poor because of mass- and heat-transfer problems. A packed-bed bioreactor with continuous aeration through the rice bed produced high protein and enzymes, but the fermented rice was difficult to remove and process due to the formation of large chunks of rice aggregates knitted together with fungal mycelia. Also, the fermentation was not uniform in the packed bed. The spouted-bed bioreactor with intermittent spouting with air achieved high production levels in both total protein and enzymes (alpha-amylase, beta-amylase, and glucoamylase) that were comparable to those found in the packed-bed bioreactor, but without the nonuniformity and solids-handling problems. However, continual spouting was found to be detrimental to this solid-state fermentation, possibly because of shear or impact damage to fungal mycelia during spouting. Increasing spouting frequency from 4-h intervals to 1-h intervals decreased protein and enzyme production. Other operating conditions critical to the fermentation include proper humidification to prevent drying of the substrate and control of reactor wall temperature to prevent excessive condensation, which would interfere with proper spouting.

Production of cell-free xanthan fermentation broth by cell adsorption on fibers

Xanthan gum is a microbial polysaccharide widely used in food and oil-drilling industries. Xanthan gum produced from the current commercial fermentation process usually contains cells and cell debris, which lower the filterability of the xanthan solution and limit its applications. The production of cell-free xanthan gum fermentation broth is thus desirable. The feasibility of removing cells from the xanthan fermentation broth by cell adsorption to various woven fibrous materials was studied. It was found that both cotton and polyester fibers could be used to adsorb Xanthomonas campestris cells present in the fermentation broth either during batch fermentation or after the fermentation. Almost all cells were removed from the fermentation broth by adsorption to fibers. Cotton terry cloth had rough surfaces and was the preferred material for cell adsorption. Cell adsorption to cotton was faster than to polyester fibers. The adsorption kinetics can be modeled by a first-order rate equation. The adsorption rate constants were 30-40% higher for cotton than for polyester. Cell adsorption was not efficient in the absence of xanthan gum, suggesting that the exopolysaccharide, xanthan gum, was important for efficient cell adsorption to fibers.