bluuebunny/crossref_metadata_2025 huggingface dataset:
Perspectives on differences in perceived external stress: a study of women and men with coronary heart disease
Authors: Hallman Tina , Perski Aleksander , Burell Gunilla , Lisspers Jan , Setterlind Sven
Published: October 2002

Focuses on diversities among women and men are rare, and few studies have focused on gender differences in psychosocial factors and coronary heart disease. The present study is one of a series in which a wide range of psychosocial factors will be analysed with a focus on women. We compared women with men as regards the impact of educational level and occupational position on differences in perceived external stress. A questionnaire (The Stress Profile) was answered by 538 rehabilitation participants (97 women, 441 men), and a reference group (5308 women, 5177 men), aged 40–65 years. Generally, women reported a higher value of perceived external stress than men. Most interesting, however, are the patterns of differences that emerged when women and men were compared in different subgroups. Women with upper secondary school education and women in white‐collar positions reported significantly higher levels of perceived external stress than men in the respective groups. When using common multivariate methods and adjusting for gender a great deal of information can be lost, and adjusting for gender makes it more difficult to find the true effect of exposures. It is only by regarding women and men separately that it is possible to link their very different working conditions and experience of stress to different health effects and vice versa. Copyright © 2002 John Wiley & Sons, Ltd.
Assessment of subjective stress in the municipal police force of the city of Rome
Authors: Pancheri P. , Martini A. , Tarsitani L. , Rosati M. V. , Biondi M. , Tomei F.
Published: October 2002

The aim of the study was to perform a dimensional assessment of subjective stress in the Municipal Police of the City of Rome. We assessed two random samples of 590 traffic police and 590 clerical police officers of both sexes for subjective stress through the administration of the ‘Rapid Stress‐Assessment Scale’ (RSA), a self‐rated tool; subjects completed the questionnaire during a non‐working day. Subsequently, from each sample we randomly included two subsamples of 115 subjects each, to whom we administered the RSA at the beginning and at the end of their shift. Significant differences between traffic and clerical police officers were found in the RSA total score, which was higher among traffic agents. Traffic police officers were found significantly more often in the ‘high stress class’. Gender differences analysis showed higher scores among women. The analysis of the subsample of 230 persons showed a significantly greater degree of the RSA ‘depression’ cluster at the end of the shift only in traffic police officers. The assessment of over‐the‐counter drug use (NSAID, analgesics, etc.) showed that, among police officers habitually using such drugs, only the traffic police subgroup scored higher on the RSA. Our results could be taken to mean that the stress response of Municipal Police officers who work outdoors is more maladaptive than that of officers working in the office; this could be compatible with the existence of different occupational stressors between the two groups. Copyright © 2002 John Wiley & Sons, Ltd.
An evolutionary perspective on strategic group emergence: a genetic algorithm‐based model
Authors: Lee Jeho , Lee Kyungmook , Rho Sangkyu
Published: October 2002

We develop a simulation model to examine conditions under which strategic groups emerge and their performance difference persists. In our model, mobility barriers, strategic interactions among high performers, dynamic capabilities (the mechanisms that allow winners to continue to survive), and boundary of rivalry are put together to derive their joint implications for the evolution of strategic groups. Not surprisingly, our model behavior shows that mobility barriers and strategic interactions play an important role in sustaining intergroup performance difference. However, the extremely high level of mobility barriers is shown to impede the emergence of strategic groups. We also find that dynamic capabilities and boundary of rivalry are as essential as mobility barriers in understanding the emergence and stability of strategic groups. When dynamic capabilities are absent or when rivalry is extended over firms with dissimilar strategies, strategic groups are less likely to exist. These findings can serve as a guideline for empirical research to probe why strategic groups exist sometimes and why they do not at other times. Copyright © 2002 John Wiley & Sons, Ltd.
Bytecode verification on Java smart cards
Authors: Leroy Xavier
Published: October 2002

This article presents a novel approach to the problem of bytecode verification for Java Card applets. By relying on prior off‐card bytecode transformations, we simplify the bytecode verifier and reduce its memory requirements to the point where it can be embedded on a smart card, thus increasing significantly the security of post‐issuance downloading of applets on Java Cards. This article describes the on‐card verification algorithm and the off‐card code transformations, and evaluates experimentally their impact on applet code size. Copyright © 2002 John Wiley & Sons, Ltd.
Extending North Atlantic oscillation reconstructions back to 1500
Authors: Luterbacher J. , Xoplaki E. , Dietrich D. , Jones P. D. , Davies T. D. , Portis D. , Gonzalez‐Rouco J. F. , von Storch H. , Gyalistras D. , Casty C. , Wanner H.
Published: October 2002

Monthly (1659–1995) and seasonal (1500–1658) North Atlantic Oscillation (NAO) indices were estimated using instrumental and documentary proxy predictors from Eurasia. Uncertainty estimates were calculated for the reconstructions, and the variability of the 500‐year winter NAO has been assessed. The late twentieth century NAO extremes are within the range of variability during earlier centuries. Copyright © 2003 Royal Meteorological Society.
Analysis of spindle microtubule organization in untreated and taxol‐treated PtK1 cells.
Authors: Snyder Judith A. , Mullins J. Michael
Published: October 2002

Taxol, a microtubule stabilizing agent, has been used to study changes in spindle microtubule organization during mitosis. PtK1 cells have been treated with 5 μg/ml taxol for brief periods to determine its effect on spindle architecture. During prophase taxol induces microtubules to aggregate, particularly evident in the region between the nucleus and cell periphery. Taxol induces astral microtubule formation in prometaphase and metaphase cells concomitant with a reduction in spindle length. At anaphase taxol induces an increase in length in astral microtubules and reduces microtubule length in the interzone. Taxol‐treated telophase cells show a reduction in the rate of furrowing and astral microtubules lack a discrete focus and are arranged more diffusely on the surface of the nuclear envelope. In summary, taxol treatment of cells prior to anaphase produces an increase in astral microtubules, a reduction in kinetochore microtubules and a decrease in spindle length. Brief taxol treatments during anaphase through early G1 promotes stabilization of microtubules, an increase in the length of astral microtubules and a delayed rate of cytokinesis.
Bovine lactoferrin in involuting mammary tissue
Authors: Hurley W. L. , Rejman J. J.
Published: October 2002

Bovine lactoferrin in involuting mammary tissue was identified by immunohistochemistry and tissue explant culture. Immunoreactive lactoferrin was associated with mammary epithelial cells. Immunostaining for lactoferrin increased during involution, in contrast to declining immunostaining of epithelia for the milk‐specific protein β‐lactoglobulin. Immunostaining for lactoferrin also was observed at the basal region of alveolar epithelia, perhaps in association with basement membrane components. Lactoferrin was preferentially synthesized in involuting mammary tissue compared with lactating tissue. Synthesis of lactoferrin in the involuting mammary gland occurs despite the apparent decline in synthesis of milk‐specific proteins.
Acid phosphatase activity in the larval salivary glands of developing Drosophila melanogaster.
Authors: Jones Helen E. , Bowen Ivor D.
Published: October 2002

Both the biochemical profile and the optical and fine structural localization of acid phosphatase activity in the larval salivary glands of developing Drosophila melanogaster is described. Biochemically, acid phosphatase shows peak activity in the glands of feeding larvae, followed by a marked decline. Directly preceding the onset of cell histolysis however, enzyme activity increases 1.5 fold and is maintained at this level. Histochemically, acid phosphatase activity initially appears as discrete point or lysosomal sources. As development proceeds, an intense and diffuse form of enzyme is seen, accompanying an extremely vacuolated cytoplasm. Ultrastructurally, the enzyme is located in lysosomes, Golgi elements, multivesicular bodies and both within, and on the extracisternal surface of the rough endoplasmic reticulum. This extracisternal or cytosolic form appears directly preceding cell lysis and eventually shows a comprehensive cellular distribution. Large numbers of acid phosphatase positive haemocytes are attached to the basal glandular surface at all developmental stages. In morphologically intact gland cells, discrete extracisternal enzyme activity appears associated with local areas of degradation.
Cell surface binding of colloidal iron and Limax flavus agglutinin compared by X‐ray microanalysis.
Authors: Thomas N. , Evans P. M. , Gwynn Ap I.
Published: October 2002

The surface characteristics of tumour cells and T‐cell hybridoma variants were examined by quantitative X‐ray microanalysis using metal‐based probes. Comparisons of populations of cells differing in invasive potential revealed differences in the binding of positive colloidal iron hydroxide, a general probe for anionic sites. Substantial differences between populations were also detected by the binding of Limax flavus agglutinin, which was used in conjunction with fetuin‐gold as a specific marker for sialic acid.
Production of the metastatic phenotype by DNA transfection in a rat mammary model.
Authors: Davies Barry R. , Barraclough Roger , Davies Michael P. A. , Rudland Philip S.
Published: October 2002

A syngeneic, immunocompetent rat mammary model has been employed to investigate the molecular basis of the metastatic phenotype. Transfection of the benign rat mammary epithelial cell line Rama 37 with the gene for p9Ka; a small, rat, calcium‐binding protein or DNA from metastatic human cell lines derived from a primary breast carcinoma or a pleural effusion yields transfectants with metastatic capabilities. Transfection of DNA from a benign human mammary cell line, a plasmid containing a cDNA for the human basic fibroblast growth factor (bFGF) gene, or the oncogene EJ‐ras‐1, fails to yield any transfectants expressing the metastatic phenotype.
Metal‐binding proteins in eggs of various sea urchin species.
Authors: Scudiero R. , Capasso C. , De Prisco P. P. , Capasso A. , Filosa S. , Parisi E.
Published: October 2002

Metallothionein presence and amount were determined in the unfertilized eggs of six sea urchin species by silver saturation assay and gel‐chromatography of cell extracts. The results showed high levels of metallothionein in the egg cytoplasm of the two Mediterranean species Paracentrotus lividus and Sphaerechinus granularis. No metallothionein was found either in the eggs of Arbacia lixula, or in those of the three Eastern species Strongylocentrotus intermedius, Temnopleurus hardwickii and Clypeaster japonicus. However, the extracts of the latter three species revealed the presence of zinc bound in a macromolecular form, thus suggesting the existence of metal‐binding proteins distinct from metallothioneins.
Dystrophin does not influence regular cytoskeletal architecture but is required for contractile performance in smooth muscle aortic cells.
Authors: Harricane Marie‐Cécile , Febris Eric , Lees Delphine , Prades Catherine , Travo Pierre , Mornet Dominique
Published: October 2002

Cultured vascular smooth muscle cells express distinct histological phenotypes due to a contractile to synthetic stage transition. In this study, we compared the behaviour of cultured aortic smooth muscle cells from young normal and mdx mice. Morphological, immunobiochemical, immunocytochemical analyses and contraction studies of these cells demonstrated that (i) the cell cytoskeleton in mdx mice is not affected by the absence of dystrophin since proteins such as caldesmon, a‐actin, and vinculin are expressed similarly in normal mice, (ii) utrophin (or dystrophin‐related protein) overexpression does not compensate for the physiological and functional role of the lacking dystrophin. These data suggested that dystrophin and utrophin cannot substitute one another and may play different or complementary roles within smooth muscle cells.
Proliferation of human leukemic pre‐B cells induced by human bone marrow stromal cells and murine fibroblasts.
Authors: Buske Christian , Hiddemann Wolfgang , Wörmann Bernhard
Published: October 2002

Aim of the study was the establishment of a standardized in vitro culture system for studies on proliferation and differentiation of human leukemic pre ‐ B cells. Coincubation with human stromal cells led to a significantly higher proliferation of the cytokine ‐ sensitive leukemic pre ‐ B cell line BLIN‐1. Clones from the murine fibroblast cell line L929 provided identical results. Coincubation with the murine cells also resulted in a significantly higher numbers of viable cells in 5 of 8 patient samples with newly diagnosed B lineage ALL. The results show that in vitro bone marrow stromal cells can be substituted by murine fibroblasts and form the basis for a simpler and more reproducible assay system.
On interleukins 4, 6 and 10 and their interrelationship with immunoglobulins G and M in common variable immunodeficiency.
Authors: Fritsch A. , Junker U. , Vogelsang H. , Jager L.
Published: October 2002

Following culture of human peripheral blood mononuclear cells (PBMNC) from 25 normal donors and 15 patients with common variable immunodeficiencv (CVID), we were unable to identify any IL10‐defective patients. Clear‐cut effects of IL4 could be demonstrated in controls, while in CVID all effects are less pronounced. While in both controls and CVID baseline levels of 1L6, IgG and IgM were found to be correlated, this was altered by the addition of either IL4 or Poke Weed Mitogen (PWM). We therefore conclude that the inability of PBMNC to produce IL10 is not the cause of CVID in our patients. In CVID, the regulating circuitry triggered by IL4 remains principally intact, however, some subgroups of CVID behave significantly differently.
Secretory proteins and growth factors of the baboon (Papio anubis) uterus: potential roles in pregnancy.
Authors: Fazleabas Asgerally T. , Hild‐Petito Sheri , Verhage Harold G.
Published: October 2002

The primate endometrium undergoes distinct morphological changes during the menstrual cycle. These alterations are regulated by the steroid hormones, estrogen and progesterone. Several lines of evidence suggest that some of these hormonally induced changes may be modulated by growth factors. Our studies have focused on characterizing the secretory activity of the uterine endometrium associated with these hormonally regulated morphological changes during the menstrual cycle and pregnancy in the baboon. Additionally, we have also attempted to study the regulation of specific growth factors and their receptors. In this review we present evidence to indicate that growth factor receptors for insulin‐like growth factor‐I (IGF‐I) and epidermal growth factor (EGF), and secretory proteins, insulin‐like growth factor binding protein‐1 (IGFBP‐1) and retinol binding protein (RBP), which are present in the glandular epithelium during the menstrual cycle, undergo cell‐specific changes in gene expression at the implantation site during pregnancy. We postulate that these alterations in growth factor receptor and secretory protein expression are conceptus modulated and may play important regulatory roles during trophoblast invasion and decidualization.
Insulin treatment (hormonal imprinting) increases the insulin production of the unicellular Tetrahymena long term. Is there a simultaneous formation of hormone receptor and hormone?
Authors: Csaba G. , Kovács P.
Published: October 2002

Insulin treatment of Tetrahymena pyriformis resulted in a long‐lasting increase in the insulin content of the cells. After about 200 generations, insulin levels significantly higher than in the control were demonstrated by using a quantitative immunocytochemical method. Although the insulin content fluctuated from day to day, it was always higher in the insulin pre‐treated (imprinted) cells than in the controls. The results emphasise the simultaneous stimulation of hormone and receptor formation by hormonal imprinting.
Colchicine‐resistance and enhancement of P‐glycoprotein activity after co‐cultivation of drug‐sensitive cells with multidrug resistant variants.
Authors: Eliseenkova A. V. , Kakpakova E. S. , Abdrjashitov R. I. , Stavrovskaya A. A.
Published: October 2002

The role of cellular interactions in the resistance of Djungurian hamster cells to colchicine (CH) and in the efficiency of P‐glycoprotein function was studied. Mixtures of CH‐resistant and CH‐sensitive cells as well as control unmixed cells were propagated for 3 days and the sensitivity of the cells to CH was measured by colony forming assay. Identification of individual subpopulations was possible due to genetic marker (6TG‐resistance). The data show that the survival of CH‐sensitive cells in CH‐supplemented medium increased after co‐cultivation with CH‐resistant counterparts. To measure Pgp activity the fluorescent dye RH123 and FACScan analysis were used. Pgp‐mediated RH123 efflux increased after co‐cultivation of CH‐sensitive and CH‐resistant cells.
Keratinocyte growth factor
Authors: Rubin Jeffrey S. , Bottaro Donald P. , Chedid Marcio , Miki Toru , Ron Dina , Cheon Hyae‐Gyeong , Taylor William G. , Fortney Emma , Sakata Hiromi , Finch Paul W. , LaRochelle William J.
Published: October 2002

Keratinocyte growth factor (KGF) is a member of the heparin‐binding fibroblast growth factor family (FGF‐7) with a distinctive pattern of target‐cell specificity. Studies performed in cell culture suggested that KGF was mitogenically active only on epithelial cells, albeit from a variety of tissues. In contrast, KGF was produced solely by cells of mesenchymal origin, leading to the hypothesis that it might function as a paracrine mediator of mesenchymal‐epithelial communication. Biochemical analysis and molecular cloning established that the KGF receptor (KGFR) was a tyrosine kinase isoform encoded by the fgfr‐2 gene. Many detailed investigations of KGF and KGFR expression in whole tissue and cell lines largely substantiated the pattern initially perceived in vitro of mesenchymal and epithelial distribution, respectively. Moreover, functional assays in organ culture and in vivo and studies of KGF regulation by sex sterorid hormones reinforced the idea that KGF acts predominantly on epithelial cells to elicit a variety of responses including proliferation, migration and morphogenesis.
Activation of macrophage‐like cells by multiple grooved substrata. Topographical control of cell behaviour.
Authors: Wójciak‐Stothard Beata , Madeja Zbigniew , Korohoda Wlodzimierz , Curtis Adam , Wilkinson Christopher
Published: October 2002

We studied the influence of substrata topography on the behaviour of murine P388D1 macrophage cell line. Cells were plated on plain fused silica substrata or substrata with microfabricated grooves of varying depth and width. Cell spread area, elongation, orientation and F‐actin content were measured on plain substratum and 6 sets of gratings. The speed and persistence of cell movement were also studied.

We found that patterned substrata substantially activated cell spreading and elongation and significantly increased the persistence and speed of cell movement, shallow grooves being more effective than deep ones. The contact of cells with micropatterned substrata significantly increased the F‐actin content in cells. The sensitivity of LPS (lipopolisaccharide) stimulated and unstimulated macrophages to topographical cues was also compared.
Germ line chimera produced by transfer of cultured chick primordial germ cells.
Authors: Chang Il‐Kuk , Yoshiki Atsushi , Kusakabe Moriaki , Tajima Atsushi , Chikamune Tateki , Naito Mitsuru , Ohno Tadao
Published: October 2002

Intrinsic primordial germ cells (PGCs) from stage 27 (5‐day‐old) chick embryonic germinal ridges were cultured in vitro for a further 5 days, and shown to proliferate on stroma cells derived from the germinal ridge. To determine whether these cultured PGCs could colonize and contribute to the germ‐line, PGCs were isolated by gentle pipetting, labeled with PKH26 fluorescent dye and injected into the blood stream of stage 17 (2.5‐day‐old) chick embryos. The recipient embryos were incubated until they reached stage 28. Thin sections of these embryos were analysed by fluorescent confocal laser microscopy. These analyses showed that the labeled donor PGCs had migrated into the germinal ridges of the recipient embryos, and transplanted PGCs had undergone at least 3‐7 divisions. These results suggest that PGCs that had passed far beyond the migration stage in vivo were still able to migrate, colonize and proliferate in recipient chick embryonic gonads.
THREE‐DIMENSIONAL STRUCTURE OF EXTRACELLULAR MATRIX REVERSIBLY REGULATES MORPHOLOGY, PROLIFERATION AND COLLAGEN METABOLISM OF PERISINUSOIDAL STELLATE CELLS (VITAMIN A‐STORING CELLS)
Authors: SENOO HARUKI , IMAI KATSUYUKI , SATO MITSURU , KOJIMA NAOSUKE , MIURA MITSUTAKA , HATA RYU‐ICHIRO
Published: October 2002

The three‐dimensional structure of the extracellular substratum was found to regulate reversibly the morphology, proliferation and collagen synthesis of perisinusoidal stellate cells (lipocytes, i.e. fat‐storing ‘Ito’ cells). On non‐coated polystyrene and type I collagen‐coated culture dishes, the cells spread well and extended their cellular processes. On the surface of type I collagen gels, the cells gathered and formed a mesh‐like structure. However, in type I collagen gel where the cells were surrounded by type I collagen three‐dimensionally, the cells extended their fine cellular processes and resembled the star‐shaped stellate cells seenin vivo. The cell proliferation was more prominent in culture dishes coated with type I collagen or in polystyrene culture dishes than on or in type I collagen gels. The collagen synthesis was affected in the same manner. These data indicate that the nature and the three‐dimensional structure of the extracellular matrix (ECM) can regulate morphology, proliferation and functions of the perisinusoidal stellate cells. In order to examine the reversibility of these regulations, we liberated cultured cells with trypsin or with purified bacterial collagenase and re‐seeded them onto or into each substratum. The cells changed their shape, rate of proliferation and collagen synthesis according to each new substratum. These results indicate that the three‐dimensional structure of ECM reversibly regulates the morphology, proliferation rate and functions of the perisinusoidal stellate cells.
LITHIUM INHIBITS GROWTH IN A MURINE NEURAL PRECURSOR CELL LINE
Authors: HASGEKAR N. N. , GOKHALE P. P. , AMIN M. K. , SESHADRI R. , LALITHA V. S.
Published: October 2002

The influence of lithium on cell growth and cell viability was studied in short‐term cultures of a neural precursor cell line (NT) developed from a murine teratocarcinoma. At very low concentrations ranging from 0.1 mmto 1 mmLi2CO3(equivalent to therapeutic blood concentrations) there was no difference between untreated and treated cultures. 10 mmlithium (Li+) was found to be toxic with 33% of cell death, while there was inhibition of growth without cell death at concentrations of 2.5 mmand 5 mmof Li+. In experiments where 2.5 mmLi+was added at the time of seeding, there was growth arrest on day 1 followed by recovery on day 2. Flow cytometric analysis revealed that cells treated with Li+were blocked in S phase. At 5 mmconcentration of Li+, the recovery occurred on day 3 and the plating efficiency was significantly low. The ability to form colonies in soft agar was reduced at 2.5 mmand 5 mmconcentrations of Li+to an equal extent. Thus, Li+has growth inhibitory as well as anchorage‐independent growth reducing effects. The NT cell line therefore would be a good model system to study the mechanism of teratogenic effect of Li+.
DIFFERENTIATION OF MESENCHYMAL LIMB BUD CELLS TO CHONDROCYTES IN ALGINATE BEADS
Authors: SHAKIBAEI M. , De SOUZA P.
Published: October 2002

Manyin vitromodels of embryonic material used for the cultivation of chondrocytes yield mixed cultures consisting of chondrocytes and fibroblast‐like cells. For the optimization of cartilage cell cultures, alginate, a semisolid medium, was employed to obtain pure chondrocyte cultures.

Isolated mesenchymal cells from 12‐day‐old mouse limb buds were grown in alginate for up to 4 weeks. A sub‐population of the cells differentiated to chondrocytes and exhibited a stable phenotype until the end of the culture period. After 3 to 4 days a cartilage‐specific matrix started to develop. Fibroblast‐like cells from this mixed culture did not survive; they became necrotic.

When alginate was later on dissolved by chelating agents, only chondrocytes were isolated. During dissolution of alginate and centrifugation, chondrocytes did not lose their contact with their new matrix present on their surfaces. Cultivation of these chondrocytes or chondrones in mass culture yields a pure chondrocyte population. Immunoelectron microscopic investigations revealed collagen type II, fibronectin, decorin and chondroitin sulfate‐proteoglycans in the chondrocyte capsules and in mass culture.
VISUALIZATION OF GOLGI APPARATUS IN METHACRYLATE EMBEDDED CONIFER EMBRYO TISSUE USING THE MONOCLONAL ANTIBODY JIM 84
Authors: EVANS DAVID E. , CLAY PATRICIA J. , ATTREE STEPHEN , FOWKE LARRY C.
Published: October 2002

Methacrylate embedding followed by resin removal has been used for the first time to visualize a membrane‐associated antigen at the tissue level. Monoclonal antibody JIM 84 was used to stain the Golgi apparatus of gymnosperm (conifer) embryos by light microscope immunocytochemistry. Specificity of labelling was confirmed by electron microscope immunocytochemistry using LR‐white resin. GA staining was evident in all stages of white spruce somatic embryo development from immature to mature. Some regions of the somatic embryos (e.g. root cap/suspensor region) stained more vigorously than other regions (hypocotyl/cotyledon end). GA also stained in roots of Monterey pine and Douglas fir. Unlike the situation in most angiosperms, JIM 84 antigen appears to be absent from the conifer plasma membrane. However, it appears to be present in representatives of both major classes of higher plants.
LASER MICROPROBE MASS SPECTROMETRY: PRINCIPLE AND APPLICATIONS IN BIOLOGY AND MEDICINE
Authors: VAN VAECK LUC , POELS KATRIEN , DE NOLLIN SONJA , HACHIMI ADAM , GIJBELS RENAAT
Published: October 2002

Laser microprobe mass spectrometry (LMMS) is an interesting technique for micro‐ and surface analysis. It employs local ionization by a focused laser under high power density conditions and subsequent mass analysis of the generated ions. This paper surveys the main LMMS instruments and their operational principles. Sample preparation is discussed in the context of biological materials. The problem of quantification is addressed. Selected examples show the way that precise information on the molecular composition can be deduced from the detected signals. Both inorganic and organic substances can be identified, even without reference spectra, from in‐situ analysis with a lateral resolution in the order of 1 to 5μm.
UNDERSTANDING INTERCELLULAR INTERACTIONS AND CELL ADHESION: LESSONS FROM STUDIES ON PROTEIN—METAL INTERACTIONS
Authors: ECKERT R. , JENEY S. , HÖRBER J. K. H.
Published: October 2002

To understand cell—cell interactions and the interactions of cells to non‐biological materials, studies on binding forces between cellular proteins and between proteins and non‐biological material such as metal surfaces are essential. The adsorption of proteins to solid—water interfaces is a multifactorial and a multistep process. First steps are determined by long‐range interactions where surface properties such as hydrophobicity, distribution of charged groups, ion concentrations and pH play important roles. In later steps structural rearrangements in the protein molecule and dehydration effects become more important making the adsorption process often irreversible. In the following we demonstrate that protein A and tubulin have a specific type of interaction to metal surfaces probably as an intermediate step in the adsorption process. The proteins were attached to the tip of a microfabricated cantilever in such a way that only one molecule interacts with the surface. By recording force—distance curves with an atomic force microscope the adhesion forces of single molecules binding to gold, titanium and indium—tinoxid surfaces were measured.
APOPTOSIS IN HUMAN LUNG EPITHELIAL CELLS: TRIGGERING BY PARAQUAT AND MODULATION BY ANTIOXIDANTS
Authors: Cappelletti Graziella , Maggioni Maria Grazia , Maci Rosalba
Published: October 2002

Recent results have shown that apoptosis is an important feature of the normal and injured lung epithelium, but little conclusive evidence is available about the exact intracellular mechanisms involved. In this work, we studied apoptotic cell death in the established human lung epithelial cell line, A549, by evaluating the ability of the pulmonary toxin, paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium dichloride), to act as a trigger, and assessing the ability of ascorbic acid and N‐acetyl‐cysteine (NAC) to modulate the process. The analysis of nuclear and cellular morphology along with TUNEL staining showed that paraquat is an inducer of apoptosis. A549 cells incubated with sublethal doses of paraquat for up to 24h showed no apoptotic features but, their following incubation in paraquat‐free medium resulted in a time‐dependent appearance of apoptosis. The antioxidants, ascorbic acid and NAC, proved effective in reducing paraquat‐induced apoptosis, and therefore were seen as protective agents. Finally, we propose an experimental model for investigating some of the key steps in the apoptotic programme in alveolar cells.
RESUMPTION OF RAPID PROLIFERATION FROM LAG PHASE IN CULTURES OF SACCHAROMYCES CEREVISIAE IN POOR NUTRIENT CONDITIONS. EFFECT OF SURFACE AND INTRACELLULAR SIGNALLING MECHANISMS
Authors: Overgaard Anne K. , Kierklo Lone , Christiansen Helle , Chrois Pernille , Rasmussen Leif , Friis JøRGEN
Published: October 2002

Saccharomyces cerevisiae was inoculated into a dilute synthetic minimal medium with glycerol as the carbon source. The number of live cells in the cultures was determined by colony counts on agar plates. Untreated control cells had doubled in number about once at the end of the first week and had gone through eight doublings by the end of the second week. Addition of either 8‐bromo‐cyclic guanosine monophosphate (8‐bromo‐cGMP) or human recombinant insulin, made the cells go through 12 and 10 doublings, respectively, by the end of the first week. In contrast, 8‐bromo‐cyclic adenosine monophosphate (8‐bromo‐cAMP) had only slight stimulating effects on cell multiplication, but if it was combined with phorbol‐12‐myristate‐13‐acetate (PMA) the cells went through about 12 doublings during the first week. Addition of LY 83583, an inhibitor of soluble guanylate cyclase, prevented cell proliferation. Further addition of 8‐bromo‐cGMP bypassed this inhibition. Singly, bradykinin or PMA did not affect cell multiplication. However, when these two compounds were combined, the cells went through about 10 doublings during the first week. Neither bradykinin, nor PMA had any releasing effect on the inhibition of LY 83583. These results indicate the existence of several routes leading to cell proliferation in wildtype S. cerevisiae cells.
GLYCERALDEHYDE‐3‐PHOSPHATE DEHYDROGENASE ASSOCIATES WITH ACTIN FILAMENTS IN SERUM DEPRIVED NIH 3T3 CELLS ONLY
Authors: Schmitz Hans‐Dirk , Bereiter‐Hahn Jürgen
Published: October 2002

The in vitro interaction between the glycolytic enzyme glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and cytoskeletal elements is well documented. To verify this association within cells, the intracellular distribution of GAPDH under various metabolic conditions has been investigated in immunostained cells or cells expressing GAPDH as a GFP fusion protein. GAPDH was homogeneously distributed in the cytoplasm and no interaction of GAPDH with cytoskeletal elements, neither with microfilaments nor microtubules or intermediate filaments, was detectable. In living cells expressing GFP‐GAPDH, stress fibres were excluded from the fluorescence. In contrast to proliferating cells, the cytoplasmic GAPDH of serum‐depleted cells was not homogeneously distributed, but colocalised with stress fibres. The mechanism for stimulating this actin‐binding affinity was independent of the NO‐signalling pathway. The results support the idea of a specialised function for the interaction of GAPDH and cytoskeletal elements, rather than a general function, as e.g. microcompartmentalization of glycolytic enzymes.
THE EFFECTS OF OXIDATIVE STRESS AND ALTERED INTRACELLULAR CALCIUM LEVELS ON VESICULAR TRANSPORT OF APOE‐EGFP
Authors: Dekroon Robert M. , Armati Patricia J.
Published: October 2002

Apolipoprotein E (apoE) plays a role in the distribution of lipid within many organs and cell types in the human body, including the central nervous system (CNS). The apoE4 isoform is also an established risk factor for late‐onset Alzheimer's disease (AD), however its role in the aetiology of the disease remains largely unknown. Therefore, as AD is a late‐onset disease, we sort to investigate how conditions hypothesised to model ageing affect apoE metabolism, such as the transport of apoE along the secretory pathway. Two of these models include oxidative stress and calcium deregulation. Using apoE‐EGFP‐expressing astrocytoma cell lines we established that vesicle number and velocity are up‐regulated under oxidative stress conditions, and slowed under KCl induced calcium deregulation. Although these findings apply to cells in general under these two stress conditions, the up‐regulation of apoE in particular may be a response to cell injury with implications for neurodegeneration such as that found with late‐onset AD.
ORGANIZATION OF FOCAL ADHESION PLAQUES IS DISRUPTED BY ACTION OF THE HIV‐1 PROTEASE
Authors: Shoeman Robert L. , Hartig Roland , Hauses Claudia , Traub Peter
Published: October 2002

Focal adhesion plaques were severely affected in human embryonic fibroblasts permeabilized with digitonin and incubated in buffer containing the human immunodeficiency virus type 1 protease (HIV‐1 PR). A mutant HIV‐1 PR (3271 HIV‐1 PR) had no effect on focal adhesion plaques. Similar effects were seen with cells microinjected with either HIV‐1 PR or 3271 HIV‐1 PR. Immunoblots of the human embryonic fibroblasts demonstrated that a number of focal adhesion plaque proteins were specifically cleaved by HIV‐1 PR. These included fimbrin, focal adhesion plaque kinase (FAK), talin, and, to a lesser extent, filamin, spectrin and fibronectin. Proteins detected by antibodies to β4 integrin and α3 integrin were also cleaved by the HIV‐1 PR. Control experiments demonstrated that the effect and protein cleavages described are due to action of the HIV‐1 PR and not to the action of endogenous host cell proteases.
Notes on the Misunderstood Buellia Dives (Th. Fr.) Th. Fr.
Authors: Giralt Mireia , Tønsberg Tor , Holien Håkon
Published: October 2002

A description of the polysporous Buellia dives (Th. Fr.) Th. Fr. is provided. It is distinct from Buellia polysporella (Nyl.) Arnold, with which it has been placed in synonomy, by the lecideine (versus lecanorine) apothecia, the dark brown (versus colourless) hypothecium and the Buellia-type (versus Physcia-type) ascospores. Further, B. polysporella is shown to be conspecific with Rinodina polyspora Th. Fr. and is reduced to synonomy with that species. Buellia dives is reported as new to Norway and Spain and notes on its ecology and distribution are given.
Emergent Marine Record and Paleoclimate of the Last Interglaciation along the Northwest Alaskan Coast
Authors: Brigham-Grette Julie , Hopkins David M.
Published: October 2002

The last interglacial high sea-level stand, the Pelukian transgression of isotope substage 5e, is recorded along the western and northern coasts of Alaska by discontinuous but clearly traceable marine terraces and coastal landforms up to about 10 m altitude. The stratigraphy indicates that sea level reached this altitude only once during the last interglacial cycle. From the type area at Nome, to St. Lawrence Island in the Bering Sea, to the eastern limit of the Beaufort Sea, Pelukian deposits contain extralimital faunas indicating that coastal waters were warmer than present. Amino acid ratios in molluscs from these deposits decrease to the north toward Barrow, consistent with the modern regional temperature gradient. Fossil assemblages at Nome and St. Lawrence Island suggest that the winter sea-ice limit was north of Bering Strait, at least 800 km north of its present position, and the Bering Sea was perennially ice-free. Microfauna in Pelukian sediments recovered from boreholes indicate that Atlantic water may have been present on the shallow Beaufort Shelf, suggesting that the Arctic Ocean was not stratified and the Arctic sea-ice cover was not perennial for some period. In coastal regions of western Alaska, spruce woodlands extended westward beyond their modern range and in northern Alaska, on the Arctic Coastal Plain, spruce groves may have entered the upper Colville River basin. The Flaxman Member of the Gubik Formation on the Alaskan Arctic Coastal Plain was deposited during marine isotope substage 5a and records the breakup of an intra-stage 5 ice sheet over northwestern Keewatin.
An Integrated Latest Quaternary (Stage 3 to Present) Paleoclimatic and Paleoceanographic Record from Offshore Northern New Zealand
Authors: Wright Ian C. , McGlone Matt S. , Nelson Campbell S. , Pillans Brad J.
Published: October 2002

Paleoceanographic and onshore paleoclimatic changes during the last 59,000 yr are established from three deep-sea sediment cores off northeast New Zealand using an integrated log of sediment texture, CaCO3 content, palynology, and planktonic and benthic foraminiferal δ18O and δ13C data, together with dated silicic tephras. These records from the isotopic stage 4-3 boundary to the present record northern New Zealand vegetation history, changes in a subsidiary equatorward flow of Circumpolar Deep Water, and sea-surface temperatures (SSTs) for subtropical water (STW) between latitudes 36°42′ and 35°51′S. Relative to the Holocene, isotopically derived SSTs record average changes of +2°C, -2°C, and -2°C for the 59,000-43,000, 43,000-24,000, and 24,000-12,000 yr time slices, respectively. The apparent +2°C warming for the 59,000-43,000 yr period is interpreted to reflect changes in the dominant depth habitat of Globigerina bulloides in response to upwelling. A -2°C cooling of SSTs during isotope stage 2 is interpreted, in part, to reflect upwelling of cool subsurface water resulting from strong and persistent westerly airflow across New Zealand, with the concomitant enhanced surface-water production of CaCO3. Onshore, vegetation consistent with these changes are recorded, with full conifer-hardwood forest prior to 43,000 yr, followed by a change to vegetation implying cooler and drier conditions between 43,000 and 12,000 yr, and a subsequent return to full forest during the Holocene. The sequence of biopelagic and hemipelagic sedimentation observed within these cores reflect oscillation of sea level about a threshold eustatic level that controls the transport of terrigenous detritus offshore. Local variations and interplay of the regional oceanography and morphology and tectonism of the continental shelf will dictate that, relative to present sea level, this threshold eustatic sea level will vary in depth, and hence age, along a continental margin. Data from the New Zealand region reveal an extremely steep meridional thermal gradient across the southern and central New Zealand region during the last glaciation with minor cooling of STW to the north, apart from localized nearshore upwelling zones, but pronounced cooling of subantarctic water to the south of the subtropical convergence zone.
Radiocarbon Geochemistry of Modern and Ancient Arctic Lake Systems, Baffin Island, Canada
Authors: Abbott Mark B. , Stafford Thomas W.
Published: October 2002

The accuracy of Arctic lake chronologies has been assessed by measuring the 14C activities of modern carbon sources and applying these isotopic mass balances to dating fossil lake materials. Small (<1 km2) shallow (<25 m) Arctic lakes with watersheds <12 km2have soil and peat stratigraphic sections with14C activities ranging from 98 to 51% Modern. The14C activity of particulate organic carbon, dissolved organic carbon, and dissolved inorganic carbon from lake and stream waters ranges from 121 to 95% Modern. The sediment–water interface of the studied lakes shows consistent14C ages of ∼100014C yr, although the14C activity of living aquatic vegetation is 115% Modern. Radiocarbon measurements of components of the lacustrine carbon pool imply that the ∼100014C yr age of the sediment–water interface results from deposition of14C-depleted organic matter derived from the watershed.
Beginnings of Olive Cultivation in Eastern Spain in Relation to Holocene Bioclimatic Changes
Authors: Terral Jean-Frederic , Arnold-Simard Genevieve
Published: October 2002

Morphometric analyses show quantitative differences in anatomical characters of wood and charcoal between wild and cultivated olive. Samples from modern olive wood in eastern Spain (Levante) provide five distinctive anatomical criteria: growth width ring, vessel surface, number of vessels per group, vessel density, and vulnerability ratio. Multivariate analysis shows that growth ring width and number of vessels per group are both significant criteria for discriminating between wild and cultivated olive. Moreover, bioclimatic environments of wild olive (thermomediterranean and mesomediterranean stages) are distinguished by vessel density. Ancient olive charcoal from archaeological sites at Valencia and Alicante implies increasing aridification from the Cardial Neolithic to the Roman Period. This pattern may reflect the onset of a Mediterranean climate and human deforestation. Charcoal from cultivated specimens of early Neolithic age shows that the olive tree is the earliest cultivated temperate fruit.
Climatic/Hydrologic Oscillations since 155,000 yr B.P. at Owens Lake, California, Reflected in Abundance and Stable Isotope Composition of Sediment Carbonate
Authors: Menking Kirsten M. , Bischoff James L. , Fitzpatrick John A. , Burdette James W. , Rye Robert O.
Published: October 2002

Sediment grain size, carbonate content, and stable isotopes in 70-cm-long (∼1500-yr) channel samples from Owens Lake core OL-92 record many oscillations representing climate change in the eastern Sierra Nevada region since 155,000 yr B.P. To first order, the records match well the marine δ18O record. At Owens Lake, however, the last interglaciation appears to span the entire period from 120,000 to 50,000 yr B.P., according to our chronology, and was punctuated by numerous short periods of wetter conditions during an otherwise dry climate. Sediment proxies reveal that the apparent timing of glacial–interglacial transitions, notably the penultimate one, is proxy-dependent. In the grain-size and carbonate-content records this transition is abrupt and occurs at ∼120,000 yr B.P. In contrast, in the isotopic records the transition is gradual and occurs between 145,000 and 120,000 yr B.P. Differences in timing of the transition are attributed to variable responses by proxies to climate change.
Glacial and Postglacial Pollen Records from the Ecuadorian Andes and Amazon
Authors: Colinvaux Paul A. , Bush Mark B. , Steinitz-Kannan Miriam , Miller Michael C.
Published: October 2002

A long pollen record is derived from sediments of a lake dammed behind a low moraine of the last glaciation at 3°S latitude in the Ecuadorian Andes and is compared with a glacial age pollen record from the Amazon rainforest immediately below. Lake Surucucho (Llaviucu) lies at 3180 m on the Amazonian flank of the Andes and above the glacial age pollen record from San Juan Bosco at 970 m. The Surucucho pollen record is interpreted as showing treeless vegetation in glacial times, advance of treeline in late-glacial time, and Holocene development of modern Andean forests. Combining the Surucucho and San Juan Bosco records shows that Andean vegetation was affected by glacial cooling at all elevations. Vegetation did not move up and down slope as belts. Rather, plant associations were reformed as temperature-sensitive species found different centers of distribution with changing temperature.
Simulating the Holocene Lake-Level Record of Lake Bysjön, Southern Sweden
Authors: Vassiljev Jüri , Harrison Sandy P. , Guiot Joël
Published: October 2002

Lake Bysjön, southern Sweden, has experienced major lake-level lowerings during the Holocene, with one interval about 9000 14C yr B.P. when water level dropped ca. 7 m and the lake became closed. These changes were not solely due to known changes in radiation budgets or seasonal temperatures. Simulations with a lake-catchment model indicate that, given the actual changes in radiation and temperatures, all the observed lake-level lowerings (including the major lowering at 9000 14C yr B.P.) could have occurred in response to precipitation changes of <75 mm/yr when winter temperatures were warmer than today. In these circumstances, the reduction of runoff into the lake caused by increased evapotranspiration during the late winter and spring, combined with relatively small changes in precipitation, was sufficient for the lake to become closed. When winter temperatures were colder than today, the reduction in winter runoff related to reduced precipitation was only very slight and insufficient to lower the lake below threshold. In such circumstances, changes in outflow were sufficient to compensate for the combined changes in precipitation and runoff, and lake level therefore remained unchanged.
Antiphasing between Rainfall in Africa's Rift Valley and North America's Great Basin
Authors: Broecker Wallace S. , Peteet Dorothy , Hajdas Irena , Lin Jo , Clark Elizabeth
Published: October 2002

The beginning of the Bølling-Allerød warm period was marked in Greenland ice by an abrupt rise in δ18O, an abrupt drop in dust rain, and an abrupt increase in atmospheric methane content. The surface waters in the Norwegian Sea underwent a simultaneous abrupt warming. At about this time, a major change in the pattern of global rainfall occurred. Lake Victoria (latitude 0°), which prior to this time was dry, was rejuvenated. The Red Sea, which prior to this time was hypersaline, freshened. Lake Lahontan, which prior to this time had achieved its largest size, desiccated. Whereas the chronologic support for the abruptness of the hydrologic changes is firm only for the Red Sea, in keeping with evidence obtained well away from the northern Atlantic in the Santa Barbara Basin and the Cariaco Trench, the onset and end of the millennial-duration climate events were globally abrupt. If so, the proposed linkage between the size of African closed basin lakes and insolation cycles must be reexamined.