bluuebunny/crossref_metadata_2025 huggingface dataset:
Geochronology, sediment provenance, and fossil emplacement at Sumidouro Cave, a classic late Pleistocene/early Holocene Paleoanthropological site in eastern Brazil
Authors: Piló Luís B. , Auler Augusto S. , Neves Walter A. , Wang Xianfeng , Cheng Hai , Edwards R. Lawrence
Published: November 2005

Peter Wilhelm Lund's (1845a) heavily debated suggestion of a contemporaneity between Paleo‐Indians and extinct Pleistocene fauna at Sumidouro Cave was re‐examined through detailed sedimentological and geochronological analyses of sediment and both human and faunal remains. Sources of the cave's sediment include both entrances as well as ceiling fissures. Non‐human fossils, on the other hand, were probably carried by floodwater through the once more‐spacious swallet entrance. Seasonal flooding reworked and mixed these two highly asynchronous assemblages. U‐series and radiocarbon ages indicate that there are at least two distinct episodes of sediment input in the cave, at ˜240,000 yr B.P. and ˜8000 yr B.P. Human remains represent a later emplacement event, probably at ˜8400 cal yr B.P. Although the human remains are of considerable age, the cave's complex stratigraphy, flooding dynamics, and extensive removal of the cave's filling during earlier excavations do not allow the determination of an unequivocal co‐existence between Paleo‐Indians and extinct megafauna at the site. © 2005 Wiley Periodicals, Inc.
Tracking neolithic interactions in southeast China: Evidence from stone adze geochemistry
Authors: Guo Zhengfu , Jiao Tianlong , Rolett Barry V. , Liu Jiaqi , Fan Xuechun , Lin Gongwu
Published: November 2005

The authors conducted a sourcing study of stone adzes recently excavated from the Damaoshan site on Dongshan Island, Fujian province, China. They used XRF, ICP‐MS, and petrographic thin‐section techniques for geochemical and petrographic analysis of six stone adzes from the site and three geological samples from Dongshan Island. The chemical data of these samples compared with other lavas in Fujian, Zhejiang, Penghu, and Taiwan suggest that the Damaoshan people imported stone raw materials either from the Penghu Archipelago in the Taiwan Strait or from the Niutoushan area on the Fujian coast. This indicates that exchange networks along the southeast coast of China, and possibly spanning the Taiwan Strait, had developed as early as 4300–5000 yr B. P. © 2005 Wiley Periodicals, Inc.
Rethinking the fourth of July Valley site: A study in glacial and periglacial geoarchaeology
Authors: Benedict James B.
Published: November 2005

The Fourth of July Valley site (5BL120) occupies the crest and inner slope of a Satanta Peak (latest Pleistocene) terminal moraine above timberline in the Indian Peaks Wilderness Area, Colorado Front Range. Excavations in 1971 suggested that a Late Paleo‐Indian lithic tradition marked by lanceolate and stemmed projectile points with parallel‐oblique flaking persisted at high altitude during the Altithermal, long after its disappearance from drought‐susceptible lowlands. Analysis of a sediment column collected in 2001 casts doubt on this interpretation. Large charred sclerotia (the resting stages of mycorrhizal fungi) show that tree islands colonized the moraine soon after deglaciation, fueling Early and Middle Holocene wildfires. Conditions became increasingly periglacial ca. 3340 yr B.P., when a lobate rock glacier advanced to the south margin of the site, altering snow‐accumulation patterns, eliminating trees, supplying meltwater that fueled ice‐lens formation, and initiating deposition of humus‐rich, snowbed loess. Large waste flakes and artifacts were frost‐sorted to the existing ground surface, where they became mixed with 6240‐year‐old wildfire charcoal in a pseudo‐occupation layer. Microflakes were too small to participate in vertical frost sorting, so remained in their original stratigraphic locations. The association of thermally altered microflakes with 8920‐year‐old charcoal in a deeply buried stratigraphic context suggests that the site was occupied during the Early Holocene and is irrelevant to the Altithermal refugium hypothesis. © 2005 Wiley Periodicals, Inc.
Short contribution: Applying micromorphological terminology to ceramic petrography
Authors: Josephs Richard L.
Published: November 2005

Micromorphological terminology used to describe soil/sediment thin sections is equally useful in the description of ceramic thin sections. The primary focus of soil micromorphology and ceramic petrography is the examination of modified geologic materials composed of sand‐, silt‐, and clay‐size particles. Protocols for describing soil or sediment in thin section are well established; however, no such guidelines exist for ceramic petrography. The author discusses how the descriptive terminology developed for soil micromorphology can be effectively used to describe thin sections prepared from archaeological ceramics. © 2005 Wiley Periodicals, Inc.
Diverse microglial responses after intrahippocampal administration of lipopolysaccharide
Authors: Herber Donna L. , Maloney Jessica L. , Roth Lisa M. , Freeman Melissa J. , Morgan Dave , Gordon Marcia N.
Published: November 2005

Inflammation has been argued to play a primary role in the pathogenesis of Alzheimer's disease by contributing to the development of neuropathology and clinical symptoms. However, the mechanisms underlying these effects remain obscure. Lipopolysaccharide (LPS) activates the innate immune response and triggers gliosis when injected into the central nervous system. In the studies described in the present work, we evaluated the time course of microgliosis after a single intrahippocampal injection of LPS. Mice were injected bilaterally with 4 μg of LPS. Post‐injection survival times were 1, 6, and 24 h, as well as 3, 7, 14, and 28 days. Protein and RNA analyses were performed for inflammatory markers. Significant elevations of cluster differentiation marker CD45, glial fibrillary acidic protein (GFAP), scavenger receptor A (SRA), and Fcγ receptor mRNA were seen after 24 h. Immunohistochemistry revealed a complex pattern of protein expression by microglia, as well as changes in cell morphologies. RNA and protein for Fcγ receptor and SRA were transiently elevated, peaked at 3 days, and returned to basal levels after 1 week. In contrast, microglia remained significantly activated through the 28‐day time point, as determined by CD45 and complement receptor 3 levels. These findings indicate a multivariate response to LPS, and evaluation of microglial phenotypes may lead to a better understanding of neuroinflammatory diseases. © 2005 Wiley‐Liss, Inc.
Generation and characterization of brain lipid‐binding protein promoter‐based transgenic mouse models for the study of radial glia
Authors: Schmid Ralf S. , Yokota Yukako , Anton E. S.
Published: November 2005

Radial glia play an essential role in the generation of the cerebral cortex through their function as neuronal precursors and as neuronal migration guides. A molecular marker for radial glia in the developing central nervous system is the brain lipid‐binding protein (BLBP). To generate mouse models for the visualization and study of radial glia, we expressed EGFP, EYFP, or dsRed2 in transgenic mice under the control of the BLBP promoter. In these transgenic lines, fluorescent protein expression is restricted to radial glia in the embryonic cortex and to astrocytes in the adult brain. Electroporation of the transgenes into embryonic cortex also resulted in radial glia‐specific transgene expression. These BLBP promoter driven transgenic mice and organotypic brain slices expressing different fluorescent markers in a radial glia‐specific manner will be useful tools to further study the differentiation and function of radial glia in distinct regions of the developing CNS. © 2005 Wiley‐Liss, Inc.
Epo protects SOD2‐deficient mouse astrocytes from damage by oxidative stress
Authors: Liu Jing , Narasimhan Purnima , Song Yun Seon , Nishi Tatsuro , Yu Fengshan , Lee Yong‐Sun , Chan Pak H.
Published: November 2005

Erythropoietin (Epo) expression, which regulates erythropoiesis, has been shown in rat and mouse brain after hypoxia. A previous study from our laboratory showed that astrocytes from manganese‐superoxide dismutase (SOD2) homozygous knockout (SOD2−/−) mice can survive under 5% O2, but not under normal aerobic conditions. However, the mechanism involved is not clear. Our preliminary study using reverse transcriptase‐polymerase chain reaction showed increased Epo mRNA expression in astrocytes cultured with 5% hypoxia compared with astrocytes under normal conditions. After administration of anti‐sense Epo, protection decreased with time. Dose‐dependent administration of Epo to SOD2−/− mouse astrocytes improved their survivability under normal conditions. Survivability of heterozygous SOD2−/+ mutant and wild‐type mouse astrocyte cultures was the same under normal conditions but, after administration of 2 mM of paraquat, a reactive oxygen species generator, survivability of the SOD2−/+ astrocytes decreased remarkably compared with the wild‐type cells. Epo administration 24 h before exposure to paraquat significantly improved the survivability of the SOD2−/+ astrocytes. Western blot studies suggest that Jak‐Stat signal transduction pathways are involved in this process. Our study demonstrates an important role for Epo in the protection of astrocytes from reactive oxygen species. We suggest that Epo can compensate in part for the antioxidant properties of mitochondrial SOD2 deficiency. © 2005 Wiley‐Liss, Inc.
Membrane currents elicited by angiotensin II in astrocytes from the rat corpus callosum
Authors: Montiel‐Herrera Marcelino , Miledi Ricardo , García‐Colunga Jesús
Published: November 2005

The corpus callosum (CC) is the main white matter tract in the brain. It consists primarily of axons and glial cells. In the present work, membrane currents generated by angiotensin II (Ang II) in cultured astrocytes from the CC of newborn and 3‐week‐old rats were studied using the whole‐cell voltage‐clamp technique. After 4 days of culture, ∼90% of cells were positive to glial fibrillary acidic protein (GFAP), indicating their astrocyte lineage. Ang II elicited inward currents in ∼20% of cells and outward currents in ∼4% of cells from the CC for newborn or 3‐week‐old rats. The main effect of Ang II on astrocytes from the newborn rat CC was a reduction of membrane conductance, by blocking of delayed rectifier K+currents in 96% of cells. However, no common action of Ang II was observed in cells from 3‐week‐old rat CC because the responses were quite variable, suggesting the participation of other ion currents. The partial agonist of AT2receptors, CGP‐42112A, exerted effects on Ang II responses, whereas the AT1antagonist ZD7155 did not, suggesting that Ang II responses in CC astrocytes are predominantly mediated by activation of AT2receptors. This study is the first to show electrical responses generated by AT2receptors in glial cells from the rat central nervous system, and may help gain a better understanding of the functions of Ang II receptors in astrocytes from the rat CC in particular and of glial cells in general. © 2005 Wiley‐Liss, Inc.
Sulfatide is essential for the maintenance of CNS myelin and axon structure
Authors: Marcus J. , Honigbaum S. , Shroff S. , Honke K. , Rosenbluth J. , Dupree J.L.
Published: November 2005

Galactocerebroside (GalC) and sulfatide are abundant myelin lipids. In mice incapable of synthesizing these lipids, myelin is thin and regionally unstable and exhibits several subtle structural abnormalities. Although galactolipid‐null mice have been beneficial in the analysis of galactolipid function, it has not been possible to differentiate between the functions of GalC and sulfatide with these mice alone. In the present work, we have analyzed a murine model that forms normal levels of GalC but is incapable of synthesizing sulfatide. By comparing a plethora of morphological features between the galactolipid‐null and the sulfatide‐null mice, we have begun to differentiate between the specific functions of these closely related lipids. The most striking difference between these two mutants is the reduction of myelin developmental abnormalities (e.g., redundant and uncompacted myelin sheaths) in young adult sulfatide‐null mice as compared with the galactolipid‐null animals. Although sulfatide appears to play a limited role in myelin development, this lipid is essential for myelin maintenance, as the prevalence of redundant, uncompacted, and degenerating myelin sheaths as well as deteriorating nodal/paranodal structure is increased significantly in aged sulfatide‐null mice as compared with littermate wildtype mice. Finally, we show that the role played by sulfatide in CNS maintenance is not limited to the myelin sheath, as axonal caliber and circularity are normal in young adult mutant mice but are significantly altered in aged sulfatide‐null animals. © 2005 Wiley‐Liss, Inc.
Cancer recurrence after total laryngectomy: Treatment options, survival, and complications
Authors: Ritoe Savitri C. , Bergman Heidi , Krabbe Paul F. M. , Kaanders Johannes H. A. M. , van den Hoogen Frank J. A. , Verbeek André L. M. , Marres Henri A. M.
Published: November 2005

Background.

A follow‐up schedule to detect asymptomatic cancer recurrence is offered to all patients with laryngeal cancer. In this study, the therapeutic options, prognosis, and morbidity of patients with total laryngectomy, who were found to have cancer recurrence during this follow‐up schedule were determined.

Methods.

Patients who had undergone a total laryngectomy between January 1, 1990, and January 1, 2000, and had cancer recurrence were included. Data from this group were analyzed retrospectively.

Results.

The prognosis was poor after the development of cancer recurrence. Curative therapy could only be offered to 27.5% of these patients. Only 5% of the patients were disease free at the end of the study period. Many patients with cancer recurrence needed interventions. A large proportion of them had complications.

Conclusions.

The follow‐up schedule offered to patients after total laryngectomy should put greater emphasis on care than on early detection of cancer recurrence. © 2005 Wiley Periodicals, Inc. Head Neck 27: 383–388, 2006
A calibration and temperature correction procedure for the water‐content reflectometer
Authors: Western Andrew W. , Seyfried Mark S.
Published: November 2005

Calibration is required for most soil moisture sensors if accurate measurements are to be obtained. This can be time consuming and costly, especially if field calibration is undertaken, but can be facilitated by a good understanding of the behaviour of the particular sensor being calibrated. We develop generalized temperature correction and soil water calibration relationships for Campbell Scientific CS615 water‐content reflectometer sensors. The temperature correction is estimated as a function of the raw sensor measurement. The calibration relationship requires one soil‐related parameter to be set. These relationships facilitate field calibration of these sensors to acceptable accuracies with only a small number of samples. Copyright © 2005 John Wiley & Sons, Ltd.
Abnormal methylation of the common PARK2 and PACRG promoter is associated with downregulation of gene expression in acute lymphoblastic leukemia and chronic myeloid leukemia
Authors: Agirre Xabier , Román‐Gómez José , Vázquez Iria , Jiménez‐Velasco Antonio , Garate Leire , Montiel‐Duarte Cristina , Artieda Paula , Cordeu Lucia , Lahortiga Idoya , Calasanz María José , Heiniger Anabel , Torres Antonio , Minna John D. , Prósper Felipe
Published: November 2005

The PARK2 gene, previously identified as a mutated target in patients with autosomal recessive juvenile parkinsonism (ARJP), has recently been found to be a candidate tumor suppressor gene in ovarian, breast, lung and hepatocellular carcinoma that maps to the third common fragile site (CFS) FRA6E. PARK2 is linked to a novel described PACRG gene by a bidirectional promoter containing a defined CpG island in its common promoter region. We have studied the role of promoter hypermethylation in the regulation of PARK2 and PACRG expression in different tumor cell lines and primary patient samples. Abnormal methylation of the common promoter of PARK2 and PACRG was observed in 26% of patients with acute lymphoblastic leukemia and 20% of patients with chronic myelogenous leukemia (CML) in lymphoid blast crisis, but not in ovarian, breast, lung, neuroblastoma, astrocytoma or colon cancer cells. Abnormal methylation resulted in downregulation of PARK2 and PACRG gene expression, while demethylation of ALL cells resulted in demethylation of the promoter and upregulation of PARK2 and PACRG expression. By FISH, we demonstrated that a lack of PARK2 and PACRG expression was due to biallelic hypermethylation and not to deletion of either PARK2 or PACRG in ALL. In conclusion, our results demonstrate for the first time that the candidate tumor suppressor genes PARK2 and PACRG are epigenetically regulated in human leukemia, suggesting that abnormal methylation and regulation of PARK2 and PACRG may play a role in the pathogenesis and development of this hematological neoplasm. © 2005 Wiley‐Liss, Inc.
The effect of hydroxyapatite nanocrystals on microvascular endothelial cell viability and functions
Authors: Pezzatini Silvia , Solito Raffaella , Morbidelli Lucia , Lamponi Stefania , Boanini Elisa , Bigi Adriana , Ziche Marina
Published: November 2005

To favor bone reconstitution with biomaterials endothelial cells should maintain proper functions to drive angiogenesis. To this aim nanocrystals of hydroxyapatite (HA) have been synthesized and characterized on endothelial cells. Microvascular endothelial cells have been exposed to stoichiometric HA nanocrystals. Cell morphology and organization of cytoskeletal proteins have been monitored by SEM analysis and immunofluorescence. Biochemical markers of physiological and pathological responses of endothelial cells, endothelial constitutive nitric oxide synthase, and cycloxygenase‐2 (ecNOS and COX‐2, respectively) have been measured by immunofluorescence. Crystallized HA sustained endothelial survival without any cytotoxic effect. At the observation with SEM, endothelial cell morphology was maintained in the presence of HA. The localization and organization of β‐actin documented the formation of stress fibers, indicating an activation of endothelial cells induced by HA nanocrystals. Immunohistochemistry for biochemical key signaling pathways in endothelium demonstrated that nanocrystals of HA maintained the expression of ecNOS and did not increase COX‐2 expression. In conclusion, the present findings indicate that HA nanocrystals exhibit high biocompatibility for microvascular endothelium. In the presence of HA nanocrystals endothelial cells maintain biochemical markers of healthy endothelium. They do not acquire a proinflammatory or thrombogenic phenotype, but express markers of functioning endothelium that might contribute to angiogenesis. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Expression profile of IGF system during lung injury and recovery in rats exposed to hyperoxia: A possible role of IGF‐1 in alveolar epithelial cell proliferation and differentiation
Authors: Narasaraju Telugu A. , Chen Haifeng , Weng Tingting , Bhaskaran Manoj , Jin Nili , Chen Jiwang , Chen Zhongming , Chinoy Mala R. , Liu Lin
Published: November 2005

Although several studies have shown that an induction of insulin‐like growth factor (IGF) components occurs during hyperoxia‐mediated lung injury, the role of these components in tissue repair is not well known. The present study aimed to elucidate the role of IGF system components in normal tissue remodeling. We used a rat model of lung injury and remodeling by exposing rats to > 95% oxygen for 48 h and allowing them to recover in room air for up to 7 days. The mRNA expression of IGF‐I, IGF‐II, and IGF‐1 receptor (IGF‐1R) increased during injury. However, the protein levels of these components remained elevated until day 3 of the recovery and were highly abundant in alveolar type II cells. Among IGF binding proteins (IGFBPs), IGFBP‐5 mRNA expression increased during injury and at all the recovery time points. IGFBP‐2 and ‐3 mRNA were also elevated during injury phase. In an in vitro model of cell differentiation, the expression of IGF‐I and IGF‐II increased during trans‐differentiation of alveolar epithelial type II cells into type‐I like cells. The addition of anti‐IGF‐1R and anti‐IGF‐I antibodies inhibited the cell proliferation and trans‐differentiation to some extent, as evident by cell morphology and the expression of type I and type II cell markers. These findings demonstrate that the IGF signaling pathway plays a critical role in proliferation and differentiation of alveolar epithelium during tissue remodeling. J. Cell. Biochem. 97: 984–998, 2006. © 2005 Wiley‐Liss, Inc.
Cell growth‐dependent subcellular localization of p8
Authors: Valacco Maria Pia , Varone Cecilia , Malicet Cédric , Cánepa Eduardo , Iovanna Juan Lucio , Moreno Silvia
Published: November 2005

p8 is a stress‐induced protein, biochemically related to the architectural factor HMG‐I/Y, overexpressed in many cancers and required for tumor expansion. The molecular mechanisms by which p8 may exert its effect in aspects of growth is unknown. Using immunocytochemistry, we found that p8 presents nuclear localization in sub‐confluent cells, but it localizes throughout the whole cell in high density grown cells. Cells arrested in Go/G1, either by serum deprivation or by hydroxyurea treatment, show a nucleo‐cytoplasmic localization of p8, whether in the rest of the cell cycle stages of actively dividing cells the localization is nuclear. A comparison of p8 sequences from human to fly predicts a conserved bipartite nuclear localization sequence (NLS). The putative NLS has been demonstrated to be functional, since nuclear import is energy dependent (inhibited by sodium azide plus 2‐deoxyglucose), and fusion proteins GFP–p8 and GFP–NLSp8 localize to the nucleus, whereas GFP–p8NLSmut in which with Lys 65, 69, 76, and 77 mutated to Ala localized to the whole cell. p8 localization does not involve the CRM1 transporter, since it is insensitive to leptomycin B. Inhibitors of MAPK pathways did not affect p8 subcellular localization. The inhibition of deacetylation with Trichostatin A promotes cytoplasmic accumulation of p8. The results suggest that p8 growth stage‐dependent localization is regulated by acetylation, that p8 is not free within the cell but forming part of a complex and that it may exert a role in both subcellular localizations. J. Cell. Biochem. 97: 1066–1079, 2006. © 2005 Wiley‐Liss, Inc.
Regulation of the p53 transcriptional activity
Authors: Liu Gang , Chen Xinbin
Published: November 2005

In response to various stresses, p53 is rapidly activated and transcriptionally regulates a number of target genes by which p53 modulates a variety of cellular activities. The transcriptional activity of p53 is delicately regulated by a plethora of cellular factors, independently or synergistically, in multiple ways in order to achieve a specific response. This article reviewed the role of the basal transcriptional machinery, co‐activators, and co‐repressors involved in p53‐dependent transcription, and the underlying mechanism by which the p53 transcriptional activity is regulated. We also discussed some potentially interesting questions and future directions in the field. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Modeling disease in the mouse: Lessons from DNA damage response and cell cycle control genes
Authors: Adelman Carrie A. , Petrini John H. J. , Attwooll Claire L.
Published: November 2005

The advent of gene targeting has allowed the dissection of many essential cellular pathways, including those involved in cell cycle regulation, signal transduction, and development. However, it is becoming increasingly clear that the simple gene deletion strategy may not be sufficient for the modeling of many cancer syndromes. In this Prospect article, we will discuss the strengths and weaknesses of mouse models, how they have advanced from gene deletions to truncations, point mutations, and conditional mouse models in which expression or loss of the gene of interest is controlled either temporally or spatially. We will also consider future directions for the use of mouse models in cancer. The vastness of the field necessitates focusing on a few specific examples with the unfortunate exclusion of many excellent studies from our discussion. As such, we focus on a few specific models of human cancer syndromes, however many of the themes discussed here are applicable to other systems of genetic manipulation and may be applied across fields. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Signaling roles of diacylglycerol kinases
Authors: Topham Matthew K.
Published: November 2005

Diacylglycerol kinases (DGKs) attenuate diacylglycerol signaling by converting this lipid to phosphatidic acid (PA). The nine mammalian DGKs that have been identified are widely expressed, but each isoform has a unique tissue and subcellular distribution. Their kinase activity is regulated by mechanisms that modify their access to diacylglycerol, directly affect their kinase activity, or alter their ability to bind to other proteins. In many cases, these enzymes regulate the activity of proteins that are modulated by either diacylglycerol or PA. Experiments using cultured cells and model organisms have demonstrated that DGKs have prominent roles in neuronal transmission, lymphocyte signaling, and carcinogenesis. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Ascorbate depletion mediates up‐regulation of hypoxia‐associated proteins by cell density and nickel
Authors: Karaczyn Aldona , Ivanov Sergey , Reynolds Mindy , Zhitkovich Anatoly , Kasprzak Kazimierz S. , Salnikow Konstantin
Published: November 2005

Exposure of human lung cells to carcinogenic nickel compounds in the presence of oxygen up‐regulated carbonic anhydrase IX (CA IX) and NDRG1/Cap43, both known as intrinsic hypoxia markers and cancer‐associated genes. This suggests that factors other than a shortage of oxygen may be involved in this induction. Both proteins can also be induced in the presence of oxygen by culturing these cells to a high density without medium change. The intracellular ascorbate measurements revealed its rapid depletion in both metal‐ and density‐exposed cells. Nickel exposure caused strong activation of HIF‐1α and HIF‐2α proteins, underscoring activation of HIF‐1‐dependent transcription. In contrast, cell density‐dependent transcription was characterized by minor induction of HIF‐1α or HIF‐2α. Moreover, the up‐regulation of NDRG1/Cap43 in HIF‐1α deficient fibroblasts suggested the involvement of different transcription factor(s). The repletion of intracellular ascorbate reversed the induction of CA IX and NDRG1/Cap43 caused by cell density or nickel exposure. Thus, the loss of intracellular ascorbate triggered the induction of both tumor markers by two different conditions in the presence of oxygen. Ascorbate is delivered to lung cells via the SVCT2 ascorbate transporter, which was found to be sensitive to nickel or cell density. Collectively these findings establish the importance of intracellular ascorbate levels for the regulation of expression of CA IX and NDRG1/Cap43. We suggest, that, in addition to low oxygenation, insufficient supply of ascorbate or its excessive oxidation in tumors, can contribute to the induction of hypoxia‐associated proteins via both HIF‐dependent and independent mechanisms. J. Cell. Biochem. 97: 1025–1035, 2006. © 2005 Wiley‐Liss, Inc.
The α1 subunit of GABAA receptor is repressed by c‐Myc and is pro‐apoptotic
Authors: Vaknin Uri A. , Hann Stephen R.
Published: November 2005

The c‐myc oncoprotein plays a critical role in the regulation of cellular proliferation and apoptosis. To mediate these biological functions, a variety of target genes are activated or repressed by c‐myc, but few genes have yet been identified that directly mediate c‐myc's role in proliferation or apoptosis. During a screen for genes that are repressed by c‐myc, we identified the α1 subunit of γ aminobutyric acid receptor (GABAAR‐α1) as a novel target of c‐myc. GABAAR is the major inhibitory neurotransmitter receptor in the mammalian central nervous system and is involved in developmental events in the brain, such as neurite outgrowth, neuronal survival, neuronal migration, and proliferation. We show here that GABAAR‐α1 expression is rapidly and directly repressed by c‐myc. GABAAR‐α1 expression is elevated in c‐myc null cells and upregulation of GABAAR‐α1 correlates with downregulation of c‐myc protein expression during neuronal cell differentiation. We also show that overexpression of GABAAR‐α1 causes apoptosis, which is blocked by the coexpression of Bcl‐2 or Bcl‐XL. Induction of apoptosis is specific for the α1 subunit, since neither the β1 or β2 subunits of GABAAR induced apoptosis. Derepression of GABAAR‐α1 expression upon downregulation of c‐myc represents a unique apoptotic mechanism and a distinct function for the α1 subunit, independent of its role as a component of the GABAAR in the plasma membrane. In addition, the regulation of GABAAR‐α1 expression by c‐myc provides a potential direct role for the Myc proteins in neurological processes and neurodegenerative disorders. J. Cell. Biochem. 97: 1094–1103, 2006. © 2005 Wiley‐Liss, Inc.
Beyond the cell cycle: A new role for Cdk6 in differentiation
Authors: Grossel Martha J. , Hinds Philip W.
Published: November 2005

Over 10 years ago, cdk6 was identified as a new member in a family of vertebrate cdc‐2 related kinases. This novel kinase was found to partner with the D‐type cyclins and to possess pRb kinase activity in vitro and has since been understood to function solely as a pRb kinase in the regulation of the G1 phase of the cell cycle. In the past 2 years, several independent studies in multiple cell types have indicated a novel role for cdk6 in differentiation. For example, cdk6 expression must be reduced to allow proper osteoblast and osteoclast differentiation, forced cdk6 expression blocked differentiation of mouse erythroid leukemia cells and cdk6 expression in primary astrocytes favors the expression of progenitor cell markers. Since exit from the cell cycle is a necessary step in terminal differentiation, down‐regulation of a mitogenic factor may be expected in this process, however it is surprising that this association has not been previously uncovered and that it is apparently not shared with cdk4, long understood to be a functional homolog of cdk6. The mechanism of cdk6 function in differentiation is not understood, but it may extend beyond the established role of cdk6 as a pRb kinase. As this story unfolds it will be important to discover if the function of cdk6 in differentiation is pRb‐dependent or pRb‐independent, since pRb has long been established as a key factor in initiating and maintaining cell cycle exit during differentiation. © 2005 Wiley‐Liss, Inc.
Transcriptional regulation of VCAM‐1 expression by tumor necrosis factor‐α in human tracheal smooth muscle cells: Involvement of MAPKs, NF‐κB, p300, and histone acetylation
Authors: Lee Chiang‐Wen , Lin Wei‐Ning , Lin Chih‐Chung , Luo Shue‐Fen , Wang Jong‐Shyan , Pouyssegur Jacques , Yang Chuen‐Mao
Published: November 2005

Tumor necrosis factor‐α (TNF‐α) has been shown to induce the expression of adhesion molecules in airway resident cells and contribute to inflammatory responses. Here, the roles of mitogen‐activated protein kinases (MAPKs) and NF‐κB in TNF‐α‐induced expression of vascular cell adhesion molecule (VCAM)‐1 were investigated in human tracheal smooth muscle cells (HTSMCs). TNF‐α‐enhanced expression of VCAM‐1 protein and mRNA as well as phosphorylation of p42/p44 MAPK, p38, and JNK were significantly attenuated by inhibitors of MEK1/2 (U0126), p38 (SB202190), and JNK (SP600125). Transfection with dominant negative mutants of MEK1/2, ERK1, ERK2, p38, and JNK attenuated TNF‐α‐induced VCAM‐1 expression. Furthermore, TNF‐α‐induced VCAM‐1 expression was significantly blocked by a selective NF‐κB inhibitor helenalin. TNF‐α‐stimulated translocation of NF‐κB into the nucleus and degradation of IκB‐α was blocked by helenalin, but not by U0126, SB202190, or SP600125. VCAM‐1 promoter activity was enhanced by TNF‐α in HTSMCs transfected with VCAM‐1‐Luc, which was inhibited by helenalin, U0126, SB202190, and SP600125. Most surprisingly, VCAM‐1 expression was also significantly blocked by a selective inhibitor of p300, curcumin. NF‐κB transcription factor and p300 were associated with the VCAM‐1 promoter, which was dynamically linked to histone H3 acetylation stimulated by TNF‐α, as determined by chromatin immunoprecipitation assay. Moreover, the resultant enhancement of VCAM‐1 expression increased the adhesion of polymorphonuclear cells (PMNs) to monolayer of HTSMCs, which was blocked by helenalin, U0126, SB202190, or SP600125. These results suggest that in HTSMCs, activation of MAPK pathways, NF‐κB, and p300 is essential for TNF‐α‐induced VCAM‐1 expression. J. Cell. Physiol. 207: 174–186, 2006. © 2005 Wiley‐Liss, Inc.
Comparative analysis of antitumor activity of CD40L, RANKL, and 4‐1BBL in vivo following intratumoral administration of viral vectors or transduced dendritic cells
Authors: Yurkovetsky Zoya R. , Shurin Galina V. , Barry Denise A. , Schuh Andre C. , Shurin Michael R. , Robbins Paul D.
Published: November 2005

The tumor necrosis factor (TNF) family comprises a group of ligands that regulate cell proliferation, differentiation, activation, maturation and apoptosis through interaction with the corresponding TNF receptor family members. In this study, we have evaluated whether adenovirus‐mediated intratumoral gene transfer of CD40L, RANKL, or 4‐1BBL elicits an immune response to established murine MC38 and TS/A tumors. Intratumoral administration of the recombinant adenoviral vectors expressing CD40L, RANKL or 4‐1BBL 7 days post‐tumor cell inoculation resulted in significant inhibition of MC38 tumor growth for all three ligands when compared with control groups treated with either saline or control adenovirus. However, intratumoral injection of Ad‐4‐1BBL or Ad‐CD40L resulted in a significantly stronger inhibition of TS/A tumor progression than did Ad‐RANKL treatment. We also demonstrated that intratumoral administration of dendritic cells (DC) transduced with adenoviral vectors encoding the TNF‐related ligands resulted in a significant inhibition of MC38 tumor growth as compared with control groups treated with Ad‐LacZ‐transduced DC or saline‐treated DC. In addition, DC overexpressing CD40L secreted considerably more IL‐12 and expressed higher levels of the co‐stimulatory molecules, CD80, CD86 and CD40, than did DC overexpressing LacZ, 4‐1BBL or RANKL. We have also demonstrated that DC/CD40L, DC/4‐1BBL, and DC/RANKL survived significantly longer than control DC or DC infected with the LacZ vector. Taken together, these results demonstrate that adenoviral gene transfer of CD40L, RANKL or 4‐1BBL elicit a significant antitumor effect in two different tumor models, with CD40L gene transfer inducing the strongest antitumor effect. Copyright © 2005 John Wiley & Sons, Ltd.
A system for efficient generation of adenovirus protein IX‐producing helper cell lines
Authors: Vellinga Jort , Uil Taco G. , de Vrij Jeroen , Rabelink Martijn J. W. E. , Lindholm Leif , Hoeben Rob C.
Published: November 2005

Background

The adenovirus 14.3 kDa hexon‐associated protein IX (pIX) functions in the viral capsid as ‘cement’ and assembles the hexons in stable groups‐of‐nine (GONs). Although viruses lacking pIX do not form GONs, and are less heat‐stable than wild‐type (wt) viruses, they can be propagated with the same kinetics and yields as the wt viruses. To facilitate ‘pseudotyping’ of adenoviral vectors we have set up an efficient system for the generation of pIX‐producing helper cell lines.

Methods

With a lentiviral pIX‐expression cassette, monoclonal and polyclonal helper cell lines were generated, which express wt or modified pIX genes at levels equivalent to wt HAdV‐5 infected cells. The incorporation efficiency into pIX gene deleted viruses was examined by Western analysis, immuno‐affinity electron microscopy, and heat‐stability assays.

Results

Immuno‐affinity electron microscopy on viruses lacking the pIX gene demonstrated that more than 96% of the particles contain pIX protein in their capsids after propagation on the pIX‐expressing helper cell lines. In addition, the pIX level in the helper cells was sufficient to generate heat‐stable particles. Finally, the ratio between pIX and fiber was equivalent to that found in wt particles. The pIX‐producing cell lines are very stable, demonstrating that pIX is not toxic to cells.

Conclusion

These data demonstrate that lentivirus vectors can be used for the establishment of pIX‐complementing helper cell lines. Copyright © 2005 John Wiley & Sons, Ltd.
Efficient cold transfection of pea ferredoxin‐NADP(H) oxidoreductase into rat hepatocytes
Authors: Mediavilla María Gabriela , Krapp Adriana , Carrillo Néstor , Rodríguez Joaquín V. , Tiribelli Claudio , Guibert Edgardo E.
Published: November 2005

We describe the use of a non‐viral, polyethylenimine‐based vector to transfect rat hepatocytes preserved under hypothermic storage. DNA sequences encoding Escherichia coli β‐galactosidase and pea ferredoxin‐NADP(H) oxidoreductase (FNR), cloned into plasmids pCH110 and pKM4 respectively, were used. FNR was detected in the liver of animals transplanted with transfected cells; no reactivity was observed in endogenous parenchyma. The expression of the transgene was transient as it was detectable up to 96 h subsequently declining to undetectable levels. In contrast to non‐transfected cells, the engraftment of FNR‐positive cells was not associated with inflammatory reaction. The percentage of FNR‐positive implanted hepatocytes was at least five times higher than the original transfection efficiency measured in vitro, while the percentage of β‐galactosidase‐positive cells was similar for both methods. These data indicate that the transfection system is effective in the transfer of plasmid DNA into hepatocytes under cold preservation and suggest the advantage of pKM4‐transfected hepatocytes on engraftment in the recipient parenchyma. Copyright © 2005 John Wiley & Sons, Ltd.
Feeling bad: antecedents and consequences of negative emotions in ongoing change
Authors: Kiefer Tina
Published: November 2005

This paper examines how and why ongoing organizational change is experienced emotionally on an everyday basis and identifies important consequences of such emotional experiences. Three main antecedents to negative emotions in ongoing change are proposed: perceptions of an insecure future; perceptions of inadequate working conditions; and perceptions of inadequate treatment by the organization. Two outcome variables are identified: trust in the organization and withdrawal from the organization. The model is tested with cross‐sectional and follow‐up data from a field study. Regression and path analysis reveal that: a) ongoing changes are associated with negative emotions; b) this relationship between ongoing changes and emotions is mediated by the three proposed antecedents; and c) negative emotions predict employee lack of trust and employee withdrawal, both immediately and one month later. Copyright © 2005 John Wiley & Sons, Ltd.
Is it pay levels or pay raises that matter to fairness and turnover?
Authors: Tekleab Amanuel G. , Bartol Kathryn M. , Liu Wei
Published: November 2005

Two studies examined the relationship between actual pay and distributive and procedural justice, and the extent to which these perceptions were related to two important pay satisfaction dimensions, pay level and pay raise, and ultimately, impacted turnover. For each study the measures of pay and justice variables were obtained on a cross‐sectional basis, while the measure of turnover was necessarily lagged. Results showed that distributive justice mediated the relationship between pay and both pay level satisfaction and pay raise satisfaction. Furthermore, distributive justice was a stronger predictor of pay level satisfaction; whereas procedural justice was a stronger predictor of pay raise satisfaction. Procedural justice also played a moderating role in Study 2. The study also showed that only pay raise satisfaction was significantly and negatively related to turnover in Study 1, and to turnover via turnover intention in Study 2. Results support the value of considering pay satisfaction as multidimensional when evaluating justice issues in a compensation context. Copyright © 2005 John Wiley & Sons, Ltd.
Self‐interest: defining and understanding a human motive
Authors: Cropanzano Russell , Goldman Barry , Folger Robert
Published: November 2005

This paper explores the concept of self‐interest. Taking a multi‐disciplinary perspective, we discuss and critique various definitions of this phenomenon. We argue that self‐interest is an important human motive. However, we also emphasize that other human motives exist. These include empathy toward others and adherence to moral duty. Copyright © 2005 John Wiley & Sons, Ltd.
Flexible work bundles and organizational competitiveness: a cross‐national study of the European work context
Authors: Stavrou Eleni T.
Published: November 2005

The present study explores the categorization of flexible work arrangements (FWAs) into bundles and their connection to organizational competitiveness in the European Union. The measures of competitiveness were performance, turnover, and absenteeism. Four moderators were used in the study, organization sector, industry sector, organization size, and organizational women‐supportiveness. The analyses revealed four FWA Bundles, namely Non‐Standard Work Patterns, Work Away from the Office, Non‐Standard Work Hours and Work Outsourced. Non‐Standard Work Patterns were found to be related to decreased turnover (in the private sector), while Work Away from the Office was related to improved performance and reduced absenteeism. Non‐Standard Work Hours and Work Outsourced (within the public sector) were positively related to turnover, suggesting that these types are possibly not being used as true flexibility arrangements. Finally, post‐hoc analysis revealed that Non‐Standard Work Hours was related to increased performance only among Swedish organizations. Implications for management and future research are discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Core self‐evaluations in Japan: relative effects on job satisfaction, life satisfaction, and happiness
Authors: Piccolo Ronald F. , Judge Timothy A. , Takahashi Koji , Watanabe Naotaka , Locke Edwin A.
Published: November 2005

The present study tested, in a non‐Western culture (Japan), the relative validity in predicting job satisfaction, life satisfaction, and happiness of core self‐evaluations (CSE), positive and negative affectivity (PA/NA), and the Neutral Objects Satisfaction Questionnaire (NOSQ). Consistent with previous results in primarily Western cultures, the four lower‐order traits that comprise CSE—self‐esteem, generalized self‐efficacy, locus of control, and neuroticism—indicated a higher‐order factor. While each lower‐order trait was itself related to the study's criteria, the CSE concept displayed in general, higher correlations with the dependent variables, and explained incremental variance in two of the study's three outcomes beyond PA, NA, and the NOSQ. These results indicate initial support for the generalizability of CSE in a culture that differs in many respects from Western cultures, and suggest that judgments of satisfaction and happiness in a non‐Western culture have a dispositional source. Copyright © 2005 John Wiley & Sons, Ltd.
Headspace single‐drop microextraction with in‐drop derivatization for aldehyde analysis
Authors: Deng Chunhui , Yao Ning , Li Ning , Zhang Xiangmin
Published: November 2005

A new technique, headspace single‐drop microextraction (HS‐SDME) with in‐drop derivatization, was developed. Its feasibility was demonstrated by analysis of the model compounds, aldehydes in water. A hanging microliter drop of solvent containing the derivatization agent of O‐2,3,4,5,6‐(pentaflurobenzyl)hydroxylamine hydrochloride (PFBHA) was shown to be an excellent extraction, concentration, and derivatization medium for headspace analysis of aldehydes by GC‐MS. Using the microdrop solvent with PFBHA, acetaldehyde, propanal, butanal, hexanal, and heptanal in water were headspace extracted and simultaneously derivatized. The formed oximes in the microdrop were analyzed by GC‐MS. HS‐SDME and in‐drop derivatization parameters (extraction solvent, extraction temperature, extraction time, stirring rate microdrop volume, and the headspace volume) and the method validations (linearity, precision, detection limit, and recovery) were studied. Compared to liquid–liquid extraction and solid‐phase microextraction, HS‐SDME with in‐drop derivatization is a simple, rapid, convenient, and inexpensive sample technique.
Analysis of the disaccharides derived from hyaluronic acid and chondroitin sulfate by capillary electrophoresis with sample stacking
Authors: Yang Yifang , Breadmore Michael C. , Thormann Wolfgang
Published: November 2005

CE conditions for monitoring the unsaturated disaccharides of hyaluronic acid (di‐HA) and chondroitin sulfate (di‐CS) using an alkaline tetraborate buffer, electrokinetic sample injection, and UV absorption detection at 232 nm are reported. Separations were performed in an uncoated fused‐silica capillary having reversed polarity and reversed electroosmosis generated with the addition of CTAB to the buffer. The influence of various separation parameters, including the concentration of CTAB, buffer pH, concentration of tetraborate, and applied voltage, on the resolution of the two disaccharides was investigated. Baseline separation was obtained with 25 mM tetraborate at pH 10.0 and having 0.05 mM CTAB. Chloride and phosphate in the sample are beneficial for the stacking of the disaccharides, with di‐HA forming a much sharper peak than di‐CS. Using samples prepared in 25 mM Tris‐HCl (pH 7.5) and electrokinetic injection at the cathode at –10 kV for 40 s, linear relationships between the corrected peak area and the concentration of the disaccharides have been found in the ranges of 1.0–400.0 and 0.1–1.0 μg/mL (0.2–1.0 μg/mL for di‐CS), with correlation coefficients being >0.9933 in all cases. The RSDs of detection times and corrected peak areas were between 1.13–1.24 and 1.57–2.13%, respectively. Applied to human serum samples that were prepared by ethanol precipitation and depolymerization of the two polysaccharides with chondroitinase ABC reveals comigration of endogenous compounds with di‐HA and a sample‐dependent detection time. The di‐HA content in the serum sample can be estimated via subtraction of the blank peak that is obtained without enzymatic hydrolysis.