bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sedimentological and stratigraphic observations in El Mirón, a late Quaternary cave site in the Cantabrian Cordillera, Northern Spain
Authors: Straus Lawrence G. , González Morales Manuel , Farrand William R. , Hubbard William J. 
Published: August 2002

AbstractEl Mirón cave on the northern edge of the Cantabrian Cordillera is one of the first montane sites in this area to be the object of modern interdisciplinary research. Five excavation seasons have revealed an archaeological sequence attributable to the Medieval, Bronze, Chalcolithic, Neolithic, Mesolithic, Azilian, Magdalenian, and Solutrean periods, and early Upper and Middle Paleolithic levels have just been reached. Forty‐four radiocarbon ages range from 900 to 41,000 14C yr B.P. Sediments in the vestibule include sediment redeposited from an ancient colluvial fill in the inner cave, limestone rock fragments, biogenic CaCO3 generated by cryptogamic and vegetation growth on the cave ceiling, eolian silts, bird droppings, and anthropogenic lithic and faunal remains. Sedimentological analyses of the cave fill reported here document the transition from a sandy silt facies with rounded cobbles in the inner vestibule to a carbonate‐rich silt facies with angular limestone clasts near the cave mouth. There is no clear regional paleoclimatic signal in the bulk sediment analyses because of the heavy influence of local input and human disturbance. Micromorphology by M.‐A. Courty (see Courty and Vallverdu [this issue]; and also Courty et al. [1989]) reveals subtle evidence for some short‐term variations that can be correlated with regional paleoclimates, such as the Younger Dryas event. © 2001 John Wiley & Sons, Inc.
Cell and tissue requirements for the gene eed during mouse gastrulation and organogenesis
Authors: Morin‐Kensicki Elizabeth M. , Faust Cynthia , LaMantia Christian , Magnuson Terry 
Published: August 2002

AbstractSummary: Mouse embryos homozygous for the allele eedl7Rn5‐3354SB of the Polycomb Group gene embryonic ectoderm development (eed) display a gastrulation defect in which epiblast cells move through the streak and form extraembryonic mesoderm derivatives at the expense of development of the embryo proper. Here we demonstrate that homozygous mutant ES cells have the capacity to differentiate embryonic cell types both in vitro as embryoid bodies and in vivo as chimeric embryos. In chimeric embryos, eed mutant cells can respond to wild‐type signals and participate in normal gastrulation movements. These results indicate a non–cell‐autonomous function for eed. Evidence of mutant cell exclusion from the forebrain and segregation within somites, however, suggests that eed has cell‐autonomous roles in aspects of organogenesis. A requirement for eed in the epiblast during embryonic development is supported by the fact that high‐contribution chimeras could not be rescued by a wild‐type extraembryonic environment. genesis 31:142–146, 2001. © 2001 Wiley‐Liss, Inc.
Codon‐improved Cre recombinase (iCre) expression in the mouse
Authors: Shimshek D.R. , Kim J. , Hübner M.R. , Spergel D.J. , Buchholz F. , Casanova E. , Stewart A.F. , Seeburg P.H. , Sprengel R. 
Published: August 2002

AbstractSummary: By applying the mammalian codon usage to Cre recombinase, we improved Cre expression, as determined by immunoblot and functional analysis, in three different mammalian cell lines. The improved Cre (iCre) gene was also designed to reduce the high CpG content of the prokaryotic coding sequence, thereby reducing the chances of epigenetic silencing in mammals. Transgenic iCre expressing mice were obtained with good frequency, and in these mice loxP‐mediated DNA recombination was observed in all cells expressing iCre. Moreover, iCre fused to two estrogen receptor hormone binding domains for temporal control of Cre activity could also be expressed in transgenic mice. However, Cre induction after administration of tamoxifen yielded only low Cre activity. Thus, whereas efficient activation of Cre fusion proteins in the brain needs further improvements, our studies indicate that iCre should facilitate genetic experiments in the mouse. genesis 32:19–26, 2002. © 2002 Wiley‐Liss, Inc.
Genetic manipulation of mouse embryonic stem cells by mutant λ integrase
Authors: Christ Nicole , Dröge Peter 
Published: August 2002

AbstractSummary: Mutant λ integrases catalyze site‐specific recombination reactions inside mammalian cells. Here we demonstrate that the integrase system can be used to eliminate resistance marker genes from the genome of mouse embryonic stem cells. So‐called integrative and excisive recombination pathways led to the precise deletion of the neomycin gene, which was inserted together with a flanking pair of directly repeated recombination sites into the ROSA26 locus by standard targeting techniques. The excision of the resistance gene led to the expression of enhanced green fluorescence protein, which served as a means to sort out cells that had undergone site‐specific recombination. Southern analysis and DNA sequencing confirmed that strand exchange reactions had occurred in the genome as expected. Hence, the integrase system may be used in conjunction with other site‐specific recombinases as a tool in genome manipulation protocols. genesis 32:203–208, 2002. © 2002 Wiley‐Liss, Inc.
Cooperative E‐box regulation of human GLI1 by TWIST and USF
Authors: Villavicencio Elisabeth H. , Yoon Joon Won , Frank Daniel J. , Füchtbauer Ernst‐Martin , Walterhouse David O. , Iannaccone Philip M. 
Published: August 2002

AbstractSummary: Sonic hedgehog signaling plays a critical role in vertebrate patterning, and signaling defects are associated with severe birth defects and cancer in man. GLI1 encodes a critical transcription activator in this pathway. GLI1 is expressed in human basal cell carcinomas and sarcomas. Despite the significance of the GLI1 gene in human disease, few immediate upstream regulators of GLI1 expression are known. We previously demonstrated that a 5′ region, including 5′ flanking sequence, an untranslated exon, and 425 bp of the first intron, regulates the human GLI1 gene. Here we show that inactivating mutations in E‐box, GC box, AP‐2, GATA, GSG, PuF, and Zeste sites identified three critical regulatory elements, including a GC box that binds Sp1 and two intronic E‐boxes that bind USF proteins or Twist. Expression of Twist but not a frame shift mutation of Twist activates the wild‐type human GLI1 regulatory sequences but not with inactivating mutations of the E‐boxes. Twist activates GLI1 reporter expression through E‐box +482 but requires binding of USF proteins to E‐box +157. Twist mutations cause human birth defects and Twist is overexpressed in many rhabdomyosarcomas, suggesting that one of Twist's primary roles is the regulation of GLI1. genesis 32:247–258, 2002. © 2002 Wiley‐Liss, Inc.
Achieving efficient delivery of morpholino oligos in cultured cells
Authors: Morcos Paul A. 
Published: August 2002

AbstractSummary: One of the many features that make morpholino oligos unique among the antisense structural types is an uncharged backbone. While this feature eliminates the nonspecific interactions of traditional S‐oligos, it also renders the morpholino undeliverable via the traditional lipid‐based delivery systems. This article describes a highly efficient method of delivering morpholino oligos into adherent and nonadherent cultured cells. In this system, a nonionic morpholino oligo is paired to a complementary DNA “carrier.” The DNA is then bound electrostatically to a partially ionized, weakly‐basic ethoxylated polyethylenimine (EPEI). This morpholino/DNA/EPEI complex is efficiently endocytosed, and when the pH drops within the endosome, the EPEI more fully ionizes, resulting in permeabilization of the endosomal membrane and release of the morpholino into the cytosol. This article describes optimization of delivery in HeLa cells and provides the basis for delivery in any cultured endocytic cell type. genesis 30:94–102, 2001. © 2001 Wiley‐Liss, Inc.
Action of morpholinos in Ciona embryos
Authors: Satou Yutaka , Imai Kaoru S. , Satoh Nori 
Published: August 2002

AbstractSummary: First, using morpholino against lacZ, we demonstrate that the morpholino specifically suppresses the translation of the gene introduced exogenously into Ciona eggs. Second, using morpholino against an alkaline phosphatase gene, we show that the morpholino suppresses the translation of the endogenous gene as well. Third, using morpholino against β‐catenin gene, we confirm that the suppression by the morpholino can be rescued by injection of β‐catenin mRNA. All of these results indicate that morpholino act in Ciona embryos to specifically block the function of endogenous genes as well as exogenously introduced genes. genesis 30: 103–106, 2001. © 2001 Wiley‐Liss, Inc.
Bidirectional transcriptional activity of PGK‐neomycin and unexpected embryonic lethality in heterozygote chimeric knockout mice
Authors: Scacheri P.C. , Crabtree J.S. , Novotny E.A. , Garrett‐Beal L. , Chen A. , Edgemon K.A. , Marx S.J. , Spiegel A.M. , Chandrasekharappa S.C. , Collins F.S. 
Published: August 2002

AbstractSummary: In an effort to create a conventional knockout mouse model for multiple endocrine neoplasia type 1 (MEN1), we targeted disruption of the mouse Men1 gene through homologous recombination in ES cells. Men1 exons 2–4 were replaced by a PGK‐neomycin cassette inserted in the opposite direction of Men1 transcription (Men1MSK/+). Unexpectedly, the Men1 conventional knockout was lethal in heterozygous, chimeric animals. Analysis of embryos revealed late gestational lethality with some embryos showing omphalocele. This was a very surprising phenotype, given that humans and mice that are heterozygotes for loss of function mutations in MEN1 are phenotypically normal except for a risk of endocrine tumors. Northern analysis of Men1MSK/+ embryonic stem cell RNA revealed the presence of an abundant, novel transcript of 2.1 kb, in addition to the expected wild‐type transcripts of 2.7 kb and 3.1 kb. RT‐PCR analysis identified this aberrant transcript as arising from the antisense strand of the PGK promoter. We hypothesize that this transcript is producing either a toxic effect at the RNA level, or a dominant negative effect through the production of an amino‐terminal truncated protein product. This example serves as a cautionary reminder that mouse knockouts using PGK‐neo may sometimes display phenotypes that reflect more than just the loss of function of the targeted gene. genesis 30:259–263, 2001. Published 2001 Wiley‐Liss, Inc.
Functional expression of Kir 6.1/SUR1‐KATP channels in frog retinal Müller glial cells
Authors: Skatchkov Serguei N. , Rojas Legier , Eaton Misty J. , Orkand Richard K. , Biedermann Bernd , Bringmann Andreas , Pannicke Thomas , Veh Rüdiger W. , Reichenbach Andreas 
Published: August 2002

AbstractThe retinae and brains of larval and adult amphibians survive long‐lasting anoxia; this finding suggests the presence of functional KATP channels. We have previously shown with immunocytochemistry studies that retinal glial (Müller) cells in adult frogs express the KATP channel and receptor proteins, Kir6.1 and SUR1, while retinal neurons display Kir6.2 and SUR2A/B (Skatchkov et al., 2001a: NeuroReport 12:1437–1441; Eaton et al., in press: NeuroReport). Using both immunocytochemistry and electrophysiology, we demonstrate the expression of Kir6.1/SUR1 (KATP) channels in adult frog and tadpole Müller cells. Using conditions favoring the activation of KATP channels (i.e., ATP‐ and spermine‐free cytoplasm‐dialyzing solution containing gluconate) in Müller cells isolated from both adult frogs and tadpoles, we demonstrate the following. First, using the patch‐clamp technique in whole‐cell recordings, tolbutamide, a blocker of KATP channels, blocks nearly 100% of the transient and about 30% of the steady‐state inward currents and depolarizes the cell membrane by 5–12 mV. Second, inside‐out membrane patches display a single‐channel inward current induced by gluconate (40 mM) and blocked by ATP (200 μM) at the cytoplasmic side. The channels apparently show two sublevels (each of ∼27–32 pS) with a total of 85‐pS maximal conductance at −80 mV; the open probability follows a two‐exponential mechanism. Thus, functional KATP channels, composed of Kir6.1/SUR1, are present in frog Müller cells and contribute a significant part to the whole‐cell K+ inward currents in the absence of ATP. Other inwardly rectifying channels, such as Kir4.1 or Kir2.1, may mediate the remaining currents. KATP channels may help maintain glial cell functions during ATP deficiency. GLIA 38:256–267, 2002. © 2002 Wiley‐Liss, Inc.
Proteasome dynamics during cell cycle in rat Schwann cells
Authors: Lafarga Miguel , Fernández Rosario , Mayo Isabel , Berciano María T. , Castaño José G. 
Published: August 2002

AbstractThe proteasome is responsible for most of the protein degradation that takes place in the cytoplasm and nucleus. Immunofluorescence and electron microscopy are used to study proteasome dynamics during the cell cycle in rat Schwann cells. During interphase, the proteasome is present in the nucleus and cytoplasm and shows no colocalization with cytoskeletal components. Some cytoplasmic proteasomes always localize in the centrosome both in interphase and in mitotic cells and only associate with microtubules during mitosis. The proteasome exits the nucleus during prophase. In anaphase, the proteasome becomes prominent in the region between the two sets of migrating chromosomes and in association with interzonal microtubules and stem bodies. In telophase, the proteasome begins to reenter the nucleus and is prominent in the midbody region until the end of cytokinesis. The proteasome does not colocalize with actin or vimentin during mitosis, except for colocalization with actin in the sheet‐like lamellipodia, which serve as substrate attachments for the cell during mitosis. During S phase, nuclear proteasomes colocalize with foci of BrdU incorporation, but this association changes with time: maximal at early S phase and declining as S phase progresses to the end. These results are discussed in relation to the biochemical pathways involved in cell cycle progression. GLIA 38:313–328, 2002. © 2002 Wiley‐Liss, Inc.
New method of purification for establishing primary cultures of ensheathing cells from the adult olfactory bulb
Authors: Nash Holly H. , Borke Rosemary C. , Anders Juanita J. 
Published: August 2002

AbstractEnsheathing cells exclusively enfold olfactory axons. The ability of olfactory axons to reinnervate the adult mammalian olfactory bulb throughout the lifetime of an organism is believed to result from the presence of this unique glial cell in the olfactory system. This theory has been substantiated by research demonstrating the ability of transplanted ensheathing cells to promote axonal regrowth in areas of the central nervous system that are normally nonpermissive. A simple method for purifying ensheathing cells resulting in a large yield of cells is therefore invaluable for transplantation studies. We have developed such a method based on the differing rates of attachment of the various harvested cell types. The greatest percentage of cells (70.4%) that attached during the first step of the separation was determined to be fibroblasts. The remainder of the cells were classified as astrocytes (20.8%) and ensheathing cells (6.8%). The percentage of attached astrocytes (67.6%) was greatly increased during the second purification step while the percentage of fibroblasts decreased greatly (27.9%) and the percentage of ensheathing cells (5.3%) slightly decreased. In the final cultures, 93.2 % of the attached cells were ensheathing cells, while astrocytes (5.9%) and fibroblasts (1.4%) were only minor components. This simple, inexpensive method of purifying ensheathing cells will facilitate their use in central nervous system regeneration research. GLIA 34:81–87, 2001. © 2001 Wiley‐Liss, Inc.
Glyt‐1 expression in cultured human Müller cells and intact retinae
Authors: Reye Peter , Penfold Philip , Pow David V. 
Published: August 2002

AbstractIn this study, we demonstrate that Müller cells cultured from human retinas are capable of strongly expressing the glycine transporter Glyt‐1 as assessed by immunocytochemistry. By contrast, intact normal and pathological human retinas exhibit Glyt‐1 immunoreactivity only in neurons. These data suggest that Glyt‐1 expression in cultured Müller cells is an epiphenomenon associated with culturing in vitro, rather than a normal physiological or even pathophysiological phenomenon in vivo. GLIA 34:311–315, 2001. © 2001 Wiley‐Liss, Inc.
Rumpshaker‐like proteolipid protein (PLP) ratio in a mouse model with unperturbed structural and functional integrity of the myelin sheath and axons in the central nervous system
Authors: Uschkureit Thomas , Spörkel Olaf , Büssow Heinrich , Stoffel Wilhelm 
Published: August 2002

AbstractThe gene plp on the X chromosome encodes the isoforms proteolipid protein (PLP) and DM20, two dominant integral membrane proteins of central nervous system (CNS) myelin. DM20 results from the activation of the cryptic splice site in exon III of the PLP gene. We inserted a sense‐orientated loxP flanked neomycin‐gene into intron III of the plp sequence, using homologous recombination in embryonic stem cells and generated the homozygous neoS mouse line. Unlike the previously described complete PLP/DM20 ablation (plp−/−), which has been obtained by introducing a neo‐gene in antisense‐orientation in the same position of intron III, the plp expression surprisingly revealed reduced mRNA levels. The PLP isoform was reduced to 50%, but DM20 expression was unaffected. This protein pattern resembles the expression profile of the PLP isoforms in the natural occurring rumpshaker mutant. Electron microscopic examination revealed a normal compaction of CNS‐myelin and maintenance of axon integrity. PLP expression levels of the wt control were recovered by Cre excision of the neo‐selection gene after intercrossing neoS mice and oligodendrocyte‐specific Cre‐mice. These data strongly hint at different functions of intron III in PLP/DM20‐specific splicing and mRNA stability. Furthermore evidence is provided for functionally affected translation products of the PLP gene in the rumpshaker mutant, whereas no PLP‐isoform occur in plp−/− mice generated by introducing a selectable marker into intron III in antisense orientation. GLIA 35:63–71, 2001. © 2001 Wiley‐Liss, Inc.
T‐ and B‐cell responses to myelin oligodendrocyte glycoprotein in experimental autoimmune encephalomyelitis and multiple sclerosis
Authors: Iglesias Antonio , Bauer Jan , Litzenburger Tobias , Schubart Anna , Linington Christopher 
Published: August 2002

AbstractThe identification of myelin oligodendrocyte glycoprotein (MOG) as a target for autoantibody‐mediated demyelination in experimental autoimmune encephalomyelitis (EAE) resulted in the re‐evaluation of the role of B cell responses to myelin autoantigens in the immunopathogenesis of multiple sclerosis. MOG is a central nervous system specific myelin glycoprotein that is expressed preferentially on the outermost surface of the myelin sheath. Although MOG is only a minor component of CNS myelin it is highly immunogenic, inducing severe EAE in both rodents and primates. In rat and marmoset models of MOG‐induced EAE demyelination is antibody‐dependent and reproduces the immunopathology seen in many cases of MS. In contrast, in mice inflammation in the CNS can result in demyelination in the absence of a MOG‐specific B cell response, although if present this will enhance disease severity and demyelination. Clinical studies indicate that autoimmune responses to MOG are enhanced in many CNS diseases and implicate MOG‐specific B cell responses in the immunopathogenesis of multiple sclerosis. This review provides a summary of our current understanding of MOG as a target autoantigen in EAE and MS, and addresses the crucial question as to how immune tolerance to MOG may be maintained in the healthy individual. GLIA 36:220–234, 2001. © 2001 Wiley‐Liss, Inc.
Müller cells in long‐term full‐thickness retinal transplants
Authors: Ghosh Fredrik 
Published: August 2002

AbstractMüller cells are essential in creating and maintaining intricate neuroretinal architecture. The functions of this important glial cell are not limited to mere support of the retinal neurons, but also include interaction in synaptic transmission and activation in response to retinal insult. In this study, we have examined Müller cell morphology and degree of activation in embryonic full‐thickness rabbit neuroretinal grafts, which were positioned under the host retina using vitrectomy technique. After surviving 3–10 months, retinal specimens were examined with hematoxylin and eosin staining and immunohistochemical analysis of vimentin and glial fibrillary acidic protein (GFAP) expression. In the host retina covering the graft, outer layers were degenerated, and vimentin‐labeled Müller cells in this area appeared short, disorganized, and displayed strong GFAP labeling. In the graft, vimentin‐labeled Müller cells spanning the retinal layers in the normal manner were found. Müller cells in 3‐month grafts were well labeled by GFAP, whereas in older grafts, GFAP labeling was very weak or absent. Our results suggest that Müller cells in well‐laminated full‐thickness retinal grafts display many of the normal morphological features and retain a normal organization even after prolonged survival times. The loss of the initial degree of Müller cell activation indicates a long‐term stability of the graft. The degeneration and gliosis of the host retina covering the graft is best explained by the merangiotic nature of the rabbit retina and may limit the usefulness of the rabbit in retinal transplantation experiments. GLIA 37:76–82, 2002. © 2002 Wiley‐Liss, Inc.
Disability and mild cognitive impairment: a longitudinal population‐based study
Authors: Artero Sylvaine , Touchon Jacques , Ritchie Karen 
Published: August 2002

AbstractObjectiveTo determine whether mild cognitive deficit is associated with parallel changes in ability to perform activities of daily living.BackgroundWhile considerable research has been conducted on the effect of senile dementia and other neurodegenerative disorders on ability to perform everyday activities, little is known about the much larger group of elderly persons suffering from mild cognitive deficits.MethodsDisability prevalence was estimated in 368 persons over the age of 65 years recruited from the general population via a general practitioner network. Subjects were followed over a 3‐year period using computerized cognitive assessment and observations of everyday functioning. Standardized neurological assessment in the third year permitted the identification of subjects who have evolved towards dementia.ResultsAn overall disability prevalence was found in the general population of 26.3%, with 30.8% in subjects with sub‐clinical cognitive impairment. Longitudinal follow‐up showed cognitive decline over time without dementia to be paralleled by changes in activity performance, with visuospatial deficits having the most marked effect on overall functioning. High intelligence quotient (IQ) and education are seen to reduce the degree of activity loss, but only when senile dementia is not present.ConclusionsDifficulties in the performance of everyday activities were found more frequently in non‐demented subjects with mild cognitive deficits than in the general population. High pre‐morbid levels of ability are seen to have a protective effect. A diagnosis of dementia should not therefore be required by persons with cognitive impairment applying for home help. Copyright © 2001 John Wiley & Sons, Ltd.