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The objectives of this study were to evaluate the delamination of convex-shaped metformin HCl (MF) and evogliptin tartrate (EG) multi-layer tablets depending on the pre-compression and main compression pressures and simultaneously correlate these results with those of a surface roughness analysis. Free-flowing MF and EG (median diameters of 38.3 and 44.7 μm, respectively) granules prepared using the wet granulation method were pre-compressed and subsequently compressed into bilayer and trilayer tablets using a universal testing machine. The compaction force required to break the tablets increased linearly as the main compression pressure increased (30-150 MPa). Conversely, the interfacial strength and compaction breaking force decreased as the pre-compression pressure increased (10-110 MPa). A surface roughness analysis employing a profilometer revealed that the first layer (MF) roughness drastically decreased from 5.89 to 0.51 μm (Ra, arithmetic average of profile height deviations from the mean line) as the pre-compression pressure increased from 10 to 150 MPa in the bilayer tablet. Accordingly, the decrease in the roughness of the first layer reduced the inter-penetration at the interface, as observed via energy dispersive spectrometer (EDS)-equipped scanning electron microscopy, decreasing the interfacial bonding strength and causing delamination of the MF/EG multi-layer tablets. These findings indicate the significance of roughness control in the actual preparation of multi-layer tablets and the usefulness of profilometer- and EDS-based surface analyses for interpreting the delamination of multi-layer tablets.

Children who experience a traumatic brain injury (TBI) are at elevated risk for a range of negative cognitive and neuropsychological outcomes. Identifying which children are at greatest risk for negative outcomes can be difficult due to the heterogeneity of TBI. To address this barrier, the current study applied a novel method of characterizing brain connectivity networks, Bayesian multi-subject vector autoregressive modelling (BVAR-connect), which used white matter integrity as priors to evaluate effective connectivity-the time-dependent relationship in functional magnetic resonance imaging (fMRI) activity between two brain regions-within the default mode network (DMN). In a prospective longitudinal study, children ages 8-15 years with mild to severe TBI underwent diffusion tensor imaging and resting state fMRI 7 weeks after injury; post-concussion and anxiety symptoms were assessed 7 months after injury. The goals of this study were to (1) characterize differences in positive effective connectivity of resting-state DMN circuitry between healthy controls and children with TBI, (2) determine if severity of TBI was associated with differences in DMN connectivity and (3) evaluate whether patterns of DMN effective connectivity predicted persistent post-concussion symptoms and anxiety. Healthy controls had unique positive connectivity that mostly emerged from the inferior temporal lobes. In contrast, children with TBI had unique effective connectivity among orbitofrontal and parietal regions. These positive orbitofrontal-parietal DMN effective connectivity patterns also differed by TBI severity and were associated with persisting behavioural outcomes. Effective connectivity may be a sensitive neuroimaging marker of TBI severity as well as a predictor of chronic post-concussion symptoms and anxiety., (© 2021 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Aims: We evaluated the clinical usefulness of a new unified glucose-insulin-potassium (GIK) regimen in a general surgical department., Methods: Surgical patients treated under the previous diverse GIK regimens (September 2016 to August 2017) and the new unified GIK regimen (September 2017 to August 2018) were identified in records of the Clinical Data Warehouse of Seoul National University Bundang Hospital. Serial and area under the curve (AUC) glucose levels, and percentages of time within the target glucose levels were compared in propensity score matched patients in the diverse GIK regimen and in the unified GIK regimen (n = 227 in each group)., Results: The AUC of glucose at 6 h and 12 h was lower under the unified GIK regimen than the diverse GIK regimen. The percentage of target glucose levels was higher in the unified GIK regimen compared to the diverse GIK regimen (81.5% vs. 75.0%, P = 0.026), but the occurrence of hypoglycaemia did not differ significantly between groups., Conclusions: The unified GIK regimen was more effective than the diverse GIK regimen for glycaemic control and did not increase the number of patients developing hypoglycaemia. This validated written GIK regimen can be safely used in a general surgical department., Competing Interests: Declaration of Competing Interest The authors declared that there is no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this paper we propose BVAR-connect, a variational inference approach to a Bayesian multi-subject vector autoregressive (VAR) model for inference on effective brain connectivity based on resting-state functional MRI data. The modeling framework uses a Bayesian variable selection approach that flexibly integrates multi-modal data, in particular structural diffusion tensor imaging (DTI) data, into the prior construction. The variational inference approach we develop allows scalability of the methods and results in the ability to estimate subject- and group-level brain connectivity networks over whole-brain parcellations of the data. We provide a brief description of a user-friendly MATLAB GUI released for public use. We assess performance on simulated data, where we show that the proposed inference method can achieve comparable accuracy to the sampling-based Markov Chain Monte Carlo approach but at a much lower computational cost. We also address the case of subject groups with imbalanced sample sizes. Finally, we illustrate the methods on resting-state functional MRI and structural DTI data on children with a history of traumatic injury.

The rational regulation of programmed cell death by means of autophagy and apoptosis has been considered a potential treatment strategy for cancer. We demonstrated the inhibitory effect of St. John's Wort (SJW) on growth in the triple-negative breast cancer (TNBC) cell line and xenografted mice and its target mechanism concerning autophagic and apoptotic cell death. SJW ethanol extract (SJWE) inhibited proliferation in a dose-dependent manner. SJWE treatment dramatically increased autophagy flux and apoptosis compared with the control. The autophagy inhibitor, 3-methyladenine (3-MA), reversed the SJWE-induced inhibition of cell proliferation and regulation of autophagy and apoptosis, indicating that SJWE induced apoptosis through prodeath autophagy. Furthermore, SJWE inhibited tumor growth and induced autophagy and apoptosis in the tumor of MDA-MB-231 xenografted athymic nude mice. Our results indicate that SJWE might have great potential as a new anticancer therapy for triple-negative breast cancer by inducing prodeath autophagy and apoptosis.

The first member of the velvet family of proteins, VeA, regulates sexual development and secondary metabolism in the filamentous fungus Aspergillus nidulans. In our study, through comparative proteome analysis using wild type and veA-deletion strains, new putative regulators of sexual development were identified and functionally analyzed. Among these, SvfA, containing a yeast survival factor 1 domain, plays multiple roles in the growth and differentiation of A. nidulans. Deletion of the svfA gene resulted in increased sensitivity to oxidative and cold stress as in yeast. The svfA-deletion strain showed an increase in bi-polar germination and a decrease in radial growth rate. The deletion strain formed structurally abnormal conidiophores and thus produced lower amounts of conidiospores during asexual development. The svfA-deletion strain produced few Hülle cells and small cleistothecia with no ascospores, indicating the requirement of svfA for the completion of sexual development. Transcription and genetic analyses indicated that SvfA modulates the expression of key development regulatory genes. Western blot analysis revealed two forms of SvfA. The larger form showed sexual-specific and VeA-dependent production. Also, the deletion of svfA caused decreased ST (sterigmatocystin) production. We propose that SvfA is a novel central regulator of growth, differentiation and secondary metabolism in A. nidulans.

Written language is a human invention that our brains did not evolve for. Yet, most research has focused on finding a single theory of reading, identifying the common set of cognitive and neural processes shared across individuals, neglecting individual differences. In contrast, we investigated variation in single word reading. Using a novel statistical method for analyzing heterogeneity in multi-subject task-based functional magnetic resonance imaging (fMRI), we clustered readers based on their brain's response to written stimuli. Separate behavioral testing and neuroimaging analysis shows that these clusters differed in the role of the sublexical pathway in processing written language, but not in reading skill. Taken together, these results suggest that individuals vary in the cognitive and neural mechanisms involved in word reading. In general, neurocognitive theories need to account not only for what tends to be true of the population, but also the types of variation that exist, even within a neurotypical population.

St. John's Wort (SJW) has been used as an estrogen agonist in the systems affected by menopause. Also, hypericin, a bioactive compound of SJW, has been used as a photosensitizer in photodynamic therapy. In the present study, we investigate the anti-proliferative and pro-apoptotic effects of SJW to demonstrate the chemo-preventive effect in human breast cancer cells. MCF-7 cells were cultured with DMSO or various concentrations of SJW ethanol extract (SJWE). Cell viability, proliferation, apoptosis, the expression of proteins involved in cell growth and apoptosis, and caspase-3/7 activity were examined. SJWE dose-dependently suppressed cell growth and induced apoptosis of MCF-7 cells. Mechanistically, SJWE enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and decreased the expression of p-mammalian target of rapamycin (p-mTOR) and p-eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1). Also, SJWE inhibited the phosphorylation of protein kinase B (Akt) and showed increases in the expression of pro-apoptotic proteins Bax and Bad with decreases in the expression of anti-apoptotic proteins including B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), and p-Bcl-2-associated death promoter (p-Bad). SJWE at 50 μg/mL showed markedly enhanced caspase-7 activation. Taken together, our results provide evidence that SJWE shows anti-proliferative and pro-apoptotic effects via inhibition of AMPK/mTOR and activation of a mitochondrial pathway. Therefore, SJWE can be used as a chemo-preventive agent without photo-activation., Competing Interests: The authors declare no conflict of interest.

Objectives/hypothesis: Mucus hypersecretion is a hallmarks of chronic rhinosinusitis. The expression of MUC5AC, a major respiratory mucin gene, is increased in chronic rhinosinusitis. The mechanisms inducing mucus hypersecretion have not been fully evaluated in chronic rhinosinusitis. Human Ca 2+ -activated Cl- channel 1 (hCLCA1) is implicated in the regulation of mucus production, airway fluid, and electrolyte transport. The present study objectives was to investigate the expression of hCLCA1 in chronic rhinosinusitis and evaluate whether its level is altered by stimulation with type 1 T helper (Th1) and Th2 cytokines, and to determine the possible role of hCLCA1 on the regulation of mucin 5AC (MUC5AC) production., Study Design: Controlled prospective study., Methods: The expression of hCLCA1 and MUC5AC in normal and inflammatory ethmoid mucosa was determined by real-time polymerase chain reaction, immunohistochemistry, and Western blot. In cultured cells, the expression of hCLCA1 and MUC5AC was measured after stimulation with Th1 and Th2 cytokines. In a supernatant, the MUC5AC level was analyzed using enzyme-linked immunosorbent assay after treatment with niflumic acid., Results: The levels of hCLCA1 and MUC5AC were increased in chronic rhinosinusitis, irrespective of nasal polyp presence, where they were distributed in superficial epithelial cells and submucosal glands. In cultured cells treated with interleukin (IL)-9, IL-4, IL-13, tumor necrosis factor-α, transforming growth factor-β, interferon-γ, and IL-1β, the expression of hCLCA1 and MUC5AC was increased. In cells treated with niflumic acid, the production of MUC5AC was inhibited., Conclusions: The current findings indicate that the expression of hCLCA1 is increased in chronic rhinosinusitis and may be regulated by Th1 and Th2 cytokines, possibly contributing to the production of MUC5AC., Level of Evidence: NA Laryngoscope, 126:E347-E355, 2016., (© 2016 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: Pollutants produced by industrial and traffic-related activities have been linked to allergic responses. These noxious agents induce their effects through the aryl hydrocarbon receptor (AhR)., Objective: We analyzed the expression and distribution pattern of AhR in normal and allergic nasal mucosa, and cytokine-driven regulation of its expression. The production levels of chemokine in cultured nasal epithelial cells were evaluated after stimulation with AhR ligand., Methods: The expression levels and distribution pattern of AhR in normal, mild, and moderate-severe persistent allergic nasal mucosa were assessed by using real-time polymerase chain reaction, Western blot, and immunohistochemistry. The expression levels of AhR were determined in cultured nasal epithelial cells treated with T-helper 2 cytokines. In cultured epithelial cells stimulated with 2-(10H-indole-30-carbonyl)-thiazole-4-carboxylic acid methyl ester, the expression levels of granulocyte macrophage colony-stimulating factor, thymus and activation regulated chemokine, macrophage inflammatory protein 1 α, monocyte chemotactic protein 1, regulated on activation normal T-cell expressed and secreted, eotaxin, and interleukin 8 were measured with real-time polymerase chain reaction and enzyme-linked immunosorbent assay., Results: Expression of AhR was observed in normal and allergic nasal mucosa where it is distributed in the epithelial layer, submucosal glands, endothelial cells, and inflammatory cells. Its expression levels are increased in allergic nasal mucosa and upregulated after stimulation with T-helper 2 cytokines. The stimulation with 2-(10H-indole-30-carbonyl)-thiazole-4-carboxylic acid methyl ester resulted in increased production of chemokines in cultured epithelial cells., Conclusion: Analysis of the study results indicated that increased expression levels of AhR may play a role in the pathogenesis of allergic rhinitis, which contributes to chemokine production in nasal mucosa.

Objective: Bitter taste receptors (TAS2Rs) are expressed in the extraoral tissues, where they possess various physiological functions. This study is to characterize TAS2Rs expression in normal and allergic nasal mucosa and analyse nasal symptom after challenge with bitter tastes to evaluate their pathophysiological function in normal and allergic nasal mucosa., Methods: The expression levels of TAS2Rs (TAS2R4, 5, 7, 10, 14, 39, and 43) in nasal mucosa were investigated by real-time PCR, Western blot, and immunohistochemistry. The expression levels of TAS2Rs and Ca(2+) imaging in cultured epithelial cells were measured after stimulation with type 2 cytokines (IL-4, IL-5, and IL-13) or bitter tastes. Nasal symptoms in control subjects and allergic rhinitis patients using visual analogue score and acoustic rhinometry were evaluated before and after stimulation with bitter tastes. Vascular diameter of rat nasal septum was measured before and after treatment with bitter tastes., Results: TAS2Rs tested here were expressed in nasal mucosa where they were commonly distributed in superficial epithelium, submucosal glands, and endothelium. Their expression levels are increased in allergic nasal mucosa and up-regulated in cultured epithelial cells simulated with type 2 cytokines. After treatment with bitter tastes, intracellular Ca(2+) signalling was increased in cultured epithelial cells, and vascular constriction was found in rat nasal septum. Increased nasal patency was observed in human nasal mucosa without pain or sneezing., Conclusion and Clinical Relevance: TAS2Rs are constitutively expressed in human nasal mucosa and their expression levels are increased in allergic nasal mucosa, where they could potentially contribute to shrinkage of normal and allergic nasal mucosa., (© 2016 John Wiley & Sons Ltd.)

The integration of transcriptomics and metabolomics can provide precise information on gene-to-metabolite networks for identifying the function of novel genes. The goal of this study was to identify novel gene functions involved in 2,3-butanediol (2,3-BDO) biosynthesis by a comprehensive analysis of the transcriptome and metabolome of five mutated Klebsiella pneumonia strains (∆wabG = SGSB100, ∆wabG∆budA = SGSB106, ∆wabG∆budB = SGSB107, ∆wabG∆budC = SGSB108, ∆wabG∆budABC = SGSB109). First, the transcriptomes of all five mutants were analyzed and the genes exhibiting reproducible changes in expression were determined. The transcriptome was well conserved among the five strains, and differences in gene expression occurred mainly in genes coding for 2,3-BDO biosynthesis (budA, budB, and budC) and the genes involved in the degradation of reactive oxygen, biosynthesis and transport of arginine, cysteine biosynthesis, sulfur metabolism, oxidoreductase reaction, and formate dehydrogenase reaction. Second, differences in the metabolome (estimated by carbon distribution, CO2 emission, and redox balance) among the five mutant strains due to gene alteration of the 2,3-BDO operon were detected. The functional genomics approach integrating metabolomics and transcriptomics in K. Pneumonia presented here provides an innovative means of identifying novel gene functions involved in 2,3-BDO biosynthesis metabolism and whole cell metabolism.

Background and Purpose: The anti-inflammatory and immunomodulatory effects of macrolides include the ability to decrease mucus secretion and inhibit inflammatory mediators in chronic rhinosinusitis. Nevertheless, their mechanisms of action remain to be determined. Here we have investigated the effects of macrolide antibiotics (clarithromycin, azithromycin and josamycin; representating the 14-, 15- and 16-membered macrolides) on endogenous steroids in human sinonasal epithelial cells and mouse nasal mucosa., Experimental Approach: The effects of macrolides on the expression of steroid-converting enzymes [11β-hydroxysteroid dehydrogenase (11β-HSD1 and 11β-HSD2)], steroid-synthesizing enzymes (3β-HSD, CYP21, CYP11B1 and CYP11A1) and cortisol levels were assessed in cultured human epithelial cells. In control and adrenalectomized mice , these enzymes and corticosterone levels were evaluated in nasal mucosa and serum after administration of macrolides., Key Results: The expression levels of 3β-HSD, CYP21, 11β-HSD1 and CYP11B1 increased in human epithelial cells treated with clarithromycin and azithromycin, whereas the expression levels of 11β-HSD2 and CYP11A1 were not affected. Josamycin had no effects on the expression of these enzymes. Cortisol levels increased in epithelial cells treated with clarithromycin or azithromycin. The expression of 3β-HSD, CYP11A1, CYP21, CYP11B1 and 11β-HSD1 was upregulated in nasal mucosa of mice treated with clarithromycin or azithromycin, but not in adrenalectomized mice., Conclusions and Implications: This study provides evidence that 14- and 15-membered macrolide antibiotics may affect the expression of steroid-synthesizing and steroid-converting enzymes in human sinonasal epithelial cells and mouse nasal mucosa, increasing the endogenous cortisol levels in sinonasal mucosa., (© 2015 The British Pharmacological Society.)

Background: The actions of glucocorticoids in target tissues depend on the local metabolism of glucocorticoids catalyzed by 11β hydroxysteroid dehydrogenase (HSD) 1 and 2. Glucocorticoids are the most effective anti-inflammatory drugs in the treatment of nasal polyps. However, the mechanisms that underlie the anti-inflammatory effects are unclear., Objective: The present study analyzed the expression of 11β-HSD1, 11β-HSD2, and steroidogenic enzymes (cytochrome P450, family 11, subfamily B, polypeptide 1 [CYP11B1]; cytochrome P450, family 11, subfamily A, polypeptide 1 [CYP11A1]) in nasal polyp tissues, and endogenous cortisol levels in nasal polyp-derived epithelial cells., Methods: The expression levels and distribution pattern of 11β-HSD1, 11β-HSD2, CYP11B1, and CYP11A1 were determined in nasal polyp tissues or nasal polyp-derived epithelial cells by using real-time polymerase chain reaction, Western blot, and immunohistochemistry testing. The expression levels of cortisol by using enzyme-linked immunosorbent assay were determined in cultured polyp-derived epithelial cells treated with adrenocorticotrophic hormone (ACTH), 11β-HSD1 inhibitor, or small interfering ribonucleic acid technique. The effect of glucocorticoids on the expression levels of these enzymes was investigated in cultured cells., Results: Expressed in nasal polyp tissues and nasal polyp-derived epithelial cells were 11β-HSD1, 11β-HSD2, CYP11B1, and CYP11A1. Cortisol production in cultured epithelial cells was decreased in cells treated with 11β-HSD1 small interfering ribonucleic acid or inhibitor, compared with nontreated cells. Cultured cells treated with adrenocorticotropic hormone induced increased cortisol production. 11β-HSD1 expression levels were upregulated in cells treated with glucocorticoid., Conclusions: Analysis of these results indicated that 11β-HSD1 expressed in polyp-derived epithelial cells may be involved in the anti-inflammatory function of glucocorticoid in the treatment of nasal polyps, which contributes to increased levels of endogenous cortisol.

Klebsiella pneumoniae (K. pneumoniae), which is a promising microorganism for industrial bulk production of 2,3-butanediol (2,3-BDO), naturally converts glucose to 2,3-BDO. The 2,3-BDO biosynthesis from glucose is composed of three steps; α-acetolactate biosynthesis by α-acetolactate synthase (budB); acetoin biosynthesis by α-acetolactate decarboxylase (budA); and 2,3-BDO biosynthesis by acetoin reductase (budC). In an effort to understand the influence of blocked 2,3-BDO pathway on K. pneumoniae glucose metabolism by budA deletion, we constructed K. pneumoniaeΔwabGΔbudA (SGSB106). Carbon flux distribution analysis, transcriptome analysis and extracellular amino acid concentration analysis were carried out to understand the effects of the budA deletion, and K. pneumoniaeΔwabG (SGSB100) was used as a control strain. Approximately 50.3% decrease in CO2 emission; and approximately 3.8-fold increase in amino acid production was observed in SGSB106. In addition to, among the amino acids, valine production significantly increased, suggesting that the branched-chain amino acid biosynthesis (BACC) in SGSB106 was activated by deletion of budA. Furthermore, whole genome transcriptome analysis of SGSB106 and SGSB100, correlates with the results from carbon distribution and amino acids concentration analyses., (Copyright © 2015 Elsevier Inc. All rights reserved.)

We have previously isolated ε-COP, the α-COP interactor in COPI of Aspergillus nidulans, by yeast two-hybrid screening. To understand the function of ε-COP, the aneA (+) gene for ε-COP/AneA was deleted by homologous recombination using a gene-specific disruption cassette. Deletion of the ε-COP gene showed no detectable changes in vegetative growth or asexual development, but resulted in decrease in the production of the fruiting body, cleistothecium, under conditions favorable for sexual development. Unlike in the budding yeast Saccharomyces cerevisiae, in A. nidulans, over-expression of ε-COP did not rescue the thermo-sensitive growth defect of the α-COP mutant at 42℃. Together, these data show that ε-COP is not essential for viability, but it plays a role in fruiting body formation in A. nidulans.

Valproic acid (VPA) is a well-known anti-epileptic and mood stabilizing drug. A growing number of reports demonstrate that VPA is neuroprotective against various insults. Despite intensive efforts to develop new therapeutics for stroke over the past two decades, all treatments have thus far failed to show clinical effect because of treatment-limiting side effects of the drugs. Therefore, a safety-validated drug like VPA would be an attractive candidate if it has neuroprotective effects against ischemic insults. The present study was undertaken to examine whether pre- and post-insult treatments with VPA protect against brain infarct and neurological deficits in mouse transient (tMCAO) and permanent middle cerebral artery occlusion (pMCAO) models. In the tMCAO (2 hr MCAO and 22 hr reperfusion) model, intraperitoneal injection of VPA (300 mg/kg, i.p.) 30 min prior to MCAO significantly reduced the infarct size and the neurological deficit. VPA treatment immediately after reperfusion significantly reduced the infarct size. The administration of VPA at 4 hr after reperfusion failed to reduce the infarct size and the neurological deficit. In the pMCAO model, treatment with VPA (300 mg/kg, i.p.) 30 min prior to MCAO significantly attenuated the infarct size, but did not affect the neurological deficit. Western blot analysis of acetylated H3 and H4 protein levels in extracts from the ischemic cortical area showed that treatment with VPA increased the expression of acetylated H3 and H4 at 2 hrs after MCAO. These results demonstrated that treatment with VPA prior to ischemia attenuated ischemic brain damage in both mice tMCAO and pMCAO models and treatment with VPA immediately after reperfusion reduced the infarct area in the tMCAO model. VPA could therefore be evaluated for clinical use in stroke patients.

Recent studies have shown that neuroblasts migrate from the subventricular zone (SVZ) into the injured area after ischemic brain insults. However, it is not well understood which mechanism mediates this ectopic migration and which types of cells migrate into the damaged region from the SVZ. The present study was designed to investigate the characteristics of the migration of nestin-positive neural stem cells toward the region of ischemic injury after focal cortical ischemia. Nestin-eGFP transgenic mice were used to effectively model the migration of SVZ cells. Photothrombotic ischemia was induced by injection of rose bengal (30 mg/kg) and exposure to cold light. Migration of nestin-positive cells was examined using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) and bromodeoxyuridine (BrdU) labeling. The number of nestin-positive cells was increased significantly in the peri-infarct area at 5 and 7 days after photothrombosis. A subset of nestin-positive cells was co-labeled with DiI or BrdU. Some of the nestin-positive cells co-expressed doublecortin (DCX) and only a few nestin-positive cells co-labeled with anti-epidermal growth factor receptor (EGFr) antibody. However, no nestin-positive cells were immunoreactive for glial fibrillary acidic protein (GFAP). The inhibition of matrix metalloproteinases (MMPs) using the MMP inhibitor, FN-439, decreased nestin-positive cells in the peri-infarct region at 7 days after photothrombosis. Although MMP-9 was not co-expressed in the nestin-positive cells in the peri-infarct cortex, MMP-9 did co-localize with GFAP-positive astrocytes. These results suggest that nestin-positive neural progenitor cells migrate into the peri-infarct cortex after photothrombotic ischemia and that MMP-9 is involved in the migration.

The system L-amino acid transporter is a major nutrient transport system that is responsible for Na+-independent transport of neutral amino acids including several essential amino acids. We have compared and examined the expressions and functions of the system L-amino acid transporters in both rat astrocyte cultures and C6 glioma cells. The rat astrocyte cultures expressed the l-type amino acid transporter 2 (LAT2) with its subunit 4F2hc, whereas the l-type amino acid transporter 1 (LAT1) was not expressed in these cells. The C6 glioma cells expressed LAT1 but not LAT2 with 4F2hc. The [14C]l-leucine uptakes by the rat astrocyte cultures and C6 glioma cells were Na+-independent and were completely inhibited by the system l selective inhibitor, BCH. These results suggest that the transport of neutral amino acids including several essential amino acids into rat astrocyte cultures and C6 glioma cells are for the most part mediated by LAT2 and LAT1, respectively. Therefore, the rat astrocyte cultures and C6 glioma cells are excellent tools for examining the properties of LAT2 and LAT1, respectively. Moreover, the specific inhibition of LAT1 in cancer cells might be a new rationale for anti-cancer therapy.

Little is known about the cellular mechanisms that cause some cells to stop dividing while leaving neighboring cells free to continue dividing. Such events occur during development of the Xenopus retina; all cells of the embryonic eyebud are mitotic, but by stage 37 (St 37), only cells at the ciliary margin continue to proliferate as neighboring cells become post-mitotic. The mechanisms that control these different proliferative fates remain unknown. One possibility is that total cell number regulates the initial number of proliferative cells at the ciliary margin. To test this hypothesis, we reduced the cell number by surgically removing a portion of the embryonic eyebud, including part of the prospective proliferative zone. Cell counts confirmed that the numbers of both the mitotic, undifferentiated cells and the post-mitotic, differentiated cells were reduced following the partial ablation. A regression analysis suggested that the initial number of undifferentiated cells was a fixed proportion of the total number, but that this proportion was increased by the partial ablation. This increase occurred for all stages that the partial ablation was performed, from early optic vesicle to mid optic cup stages. The proportion of undifferentiated cells was normal in sham-operated retinas, indicating that the increase in partially ablated retinas was induced by tissue removal and not by wound healing. Analyses of clones derived from single precursors, labeled with a fluorescent lineage tracer, indicated that the rate of proliferation was the same in partially ablated and sham-operated retinas. Measurements of bromodeoxyuridine incorporation directly confirmed that at the ciliary margin cell division time was unchanged after partial ablation. Our observations are most consistent with the hypothesis that the proportion of undifferentiated cells was increased because cells that would have become post-mitotic remained proliferative after the partial ablation. Furthermore, cell-cell interactions most likely play a major role in controlling the initial number of proliferative cells in the tadpole retina.