bluuebunny/crossref_metadata_2025 huggingface dataset:
INSULIN PRODUCES A BIPHASIC RESPONSE INTETRAHYMENA THERMOPHILABY STIMULATING CELL SURVIVAL AND ACTIVATING PROLIFERATION IN TWO SEPARATE CONCENTRATION INTERVALS
Authors: CHRISTENSEN SØREN T. , QUIE HELENE , KEMP KÅRE , RASMUSSEN LEIF
Published: October 2002

Cells ofTetrahymenamay produce autocrine signal molecules with effects on survival and proliferation. Here we have tested the effects of human recombinant and bovine insulin, and the B22–B30 fragment of bovine insulin over a wide range of concentrations (10−5–10−18m) on cell survival and proliferation in a synthetic nutrient medium. The cells were grown in conical flasks at low initial cell densities (40 and 400cells/ml). Insulin prevented rapid cell death and/or promoted cell proliferation over two separate concentration ranges: down to nanomolar levels and again in the low pico‐ and femtomolar range. At an initial population density of 400cells/ml the cells multiplied at both concentration intervals. At 40 or fewer organisms/ml the cells multiplied in the high concentration interval, whereas in the low interval they survived for about four times longer than those in the control cultures. B22–B30 added to cultures of 40 initial cells/ml produced a stimulation of cell survival in the low pico‐ and high femtomolar range. In the presence of hemin (50nm) cells at 400 initial organisms/ml multiplied at insulin concentrations down to about 3nmand again from 300amto 10pm. In some cases, hemin plus insulin activated cell proliferation between the two concentration intervals as well. At 40cells/ml the cells not only survived but proliferated in the femtomolar range. Cells in cultures supplemented with both hemin and B22–B30 multiplied at the low concentration interval (from about 100fmto 10pm).
MOSQUITO LARVAE EXTRACT INDUCES MITOTIC RATE ALTERATIONS OF MICE TONGUE KERATINOCYTES ALONG A CIRCADIAN RHYTHM PERIOD
Authors: RONDEROS J. R. , RICCILLO F. L. , OTTINO A.
Published: October 2002

It has been demonstrated that the crude extract of mosquito larvae alters the mitotic rate of several mouse cell populations of young growing mice (25±1 days old). Furthermore, the dialysed fraction of the extract inhibited proliferation of hepatocytes from hepatectomized adult male mice (90 days old). Sampling during the period between 16 and 24 h after treatment (when mitotic peak normally occurs) shows an inhibiting effect on the G1/S interphase, whereas evaluation during the dark phase of the circadian rhythm period (i.e. 4 to 12 h after treatment) shows an increment of the mitotic rates suggesting a probable effect at G2/M restriction point. In the present paper we report the effect of the mosquito larvae crude extract on the proliferative activity of tongue keratinocytes along a circadian rhythm period. Treatments were intra‐peritoneally applied at 16/00 Time of Day/Time Post Injection and mice were killed at 00/08, 04/12, 08/16, 12/20 and 16/24 TD/TPI. As other cell populations previously analysed, the mitotic rate of tongue keratinocytes of extract receivers was significantly increased during night (when S phase normally occurs) and inhibited during the 08/16 to 16/24 period.
THE ROLE OF REACTIVE OXYGEN METABOLITES IN THE TRANSCRIPTIONAL REGULATION OF IFN‐γ GENE EXPRESSION BY HISTAMINE IN NK CELLS FOLLOWING IL‐2 STIMULATION
Authors: HOUZE THOMAS A. , LARSSON PER‐ANDERS , HELLSTRAND KRISTOFFER , GUSTAVSSON BENGT
Published: October 2002

The secretion of interferon‐γ (IFN‐γ) by natural killer (NK) cells following in vitro stimulation with interleukin‐2 (IL‐2) is inhibited by co‐incubation with autologous monocytes at a transcriptional level by more than sixty‐fold. In this study, we investigate the nature of the inhibitory signal and particularly the role of reactive oxygen metabolites (ROMs). It was found that the inhibition of IFN‐γ was operating at a pre‐translational level, this was indicated by the inability of CD 56+‐enriched natural killer cells to accumulate IFN‐γ mRNA in the presence of elutriated monocytes. Both catalase, a scavenger of hydrogen peroxide and histamine, a biogenic amine which inhibits the generation of ROMs by monocytes, strongly abrogated the inhibition of IFN‐γ production. We thereby conclude that histamine behaves synergistically with IL‐2 at a transcriptional level to induce IFN‐γ even in an admixture of NK cells and monocytes.
PRODUCTION OF BIOLOGICALLY ACTIVE HUMAN RELA (p65) IN BACULOVIRUS‐INFECTED INSECT CELLS
Authors: CHABOT‐FLETCHER MARIE , HO MAUREEN L. , BRETON JOHN J. , HANNING CHARLES R. , AMEGADZIE BERNARD Y.
Published: October 2002

A recombinant baculovirus was constructed to express a cDNA encoding RelA (p65), a member of the NF‐κB/Rel family of proteins. Infection of Spodoptera frugiderda insect cells with the recombinant baculovirus resulted in the production of the biologically active protein as measured by immunoblotting using RelA‐specific antisera and by electrophoretic mobility shift assays. The recombinant protein bound specifically to an oligonucleotide containing the NF‐κB consensus motif but not to that containing the unrelated Oct‐1 consensus motif. Thus insect cell‐derived RelA possess properties similar to the native protein and may be used in physical, biochemical, and pharmacological studies.
STRUCTURAL AND FUNCTIONAL ROLES OF CYTOSKELETAL PROTEINS DURING REPAIR OF NATIVE GUINEA PIG INTESTINAL EPITHELIUM
Authors: ALBERS THERESA M. , LOMAKINA INNA , MOORE RONDA P.
Published: October 2002

The cytoskeletal events that assist restitution of the native intestinal epithelium are poorly understood. To enhance our understanding of repair mechanisms in the native intestinal epithelium we assessed the functional role of actin and the temporal and spatial alterations in actin and villin that occur in native enterocytes migrating in response to injury. Using a well‐characterized in vitro Ussing chamber model of native intestine epithelial restitution, the actin inhibitor cytochalasin D (CD) was applied to determine the functional importance of actin to restitution as assessed by sensitive electrophysiological means and structural techniques. Additionally we used phalloidin and indirect immunohistochemistry to localize and semi‐quantitate F‐actin and villin in migrating cells during restitution. We report new data that shows that when cytoskeletal changes were impaired with CD, the epithelial monolayer was re‐established in fewer than 20% of CD‐treated villi, cells bordering the epithelial defect did not assume the characteristic phenotype associated with migrating cells, and transepithelial resistance did not return to pre‐injury levels. F‐actin and villin were present at the leading edge of the migrating cells, basolateral F‐actin was decreased, and cytoplasmic villin was increased as determined by phalloidin and immunohistochemical methods. We conclude that in vitro repair of the native intestinal epithelium is functionally and structurally dependent on major changes in the cytoskeleton of cells involved in re‐establishing the epithelial monolayer over a complex extracellular matrix.
PANCREAS OF ASELLI IN SOME SPECIES OF THE SHREWS (SOREX ARANEUS & NEOMYS FODIENS) AS AN ANALOGUE OF THE BURSA OF FABRICIUS IN BIRDS
Authors: TSIPERSON VLADISLAV P.
Published: October 2002

No organ equivalent to the bursa of Fabricius in birds, which is responsible for the production of B cells, has been found in mammals thus far. It has been suggested that Peyer's patches and the appendix along with the bone marrow play this role. In this study, the gland of Aselli of shrews was examined, whose function has not yet been clarified. The results of the study of the gland of Aselli in common and water shrews suggest this gland to be the key lymphoid organ analogous to the bursa of Fabricius. However, unlike the bursa of Fabricius, the gland of Aselli seems to fulfil two functions. It not only produces B cells, but also is the site of their terminal differentiation into plasma cells.
CHARACTERIZATION OF THE Na+K+‐ATPase IN ISOLATED BOVINE ARTICULAR CHONDROCYTES; MOLECULAR EVIDENCE FOR MULTIPLE α AND β ISOFORMS
Authors: MOBASHERI A. , ERRINGTON R. J. , GOLDING S. , HALL A. C. , URBAN J. P. G.
Published: October 2002

We have used isoform‐specific antibodies against the Na+K+‐ATPase αα1, α2 and α3) and ββ1 and β2) subunit isoforms in order to establish their specific localization in isolated bovine articular chondrocytes. Immunoblotting confirmed the presence of the α1 and α3 isoforms, although α1 expression was significantly greater than α3 as assessed by immunofluorescence confocal laser scanning microscopy and PCR. A similar approach revealed the presence of the β1 and β2 isoforms in chondrocytes, although β2 immunostaining on the plasma membrane was more punctate than β1 which in contrast predominated in a subcellular compartment. The plasma membrane abundance of the Na+K+‐ATPase was found to be sensitive to the extracellular ionic concentration and long‐term elevation of extracellular Na+concentration significantly upregulated Na+K+‐ATPase density as measured by specific3H‐ouabain binding. Our observations suggest that the expression of α3 and β2 is not restricted to excitable tissues as previously reported. The physiological relevance of α3 expression in chondrocytes may be related to its low affinity for intracellular Na+in an extracellular environment where Na+concentration is unusually high (260–350mm) compared to other cell types (140mm). Glycoproteins and their branched carbohydrates have been implicated in cell recognition events, thus the β2 subunit glycoprotein may allow the chondrocyte to detect changes in its extracellular environment by physically interacting with components of the cellular cytoskeleton and matrix macromolecules.
CHANGES OF PHOSPHATIDYLCHOLINE‐SPECIFIC PHOSPHOLIPASE C IN HEPATOCARCINOGENESIS AND IN THE PROLIFERATION AND DIFFERENTIATION OF RAT LIVER CANCER CELLS
Authors: XINGZHONG WU , LU HONG , ZHOU LAN , HUANG YONG , CHEN HUILI
Published: October 2002

The biological significance of phosphatidylcholine‐specific phospholipase C (PC‐PLC) in hepatocarcinogenesis and the proliferation and differentiation of rat liver cancer cells was investigated. The Ca2+‐dependent activities of PC‐PLC gradually increased during N‐nitrosodiethylamine (DEN)‐induced hepatocarcinogenesis and peaked at weeks 18–20 when the tumour formed. There was a close relationship between Ca2+‐dependent PC‐PLC activities and cellular DNA content, membranous γ‐glutamyltranspeptidase (γ‐GT), and tyrosine protein kinase. In contrast, Ca2+‐independent PC‐PLC activities decreased during hepatocarcinogenesis. Similarly, when CBRH‐7919 rat liver cancer cells were treated with phorbol 12‐myristate 13‐acetate, a proliferation stimulator of the cells, γ‐GT and Ca2+‐dependent activities of PC‐PLC and the expression of α‐fetoprotein increased significantly. However, when these cells were induced by retinoic acid to differentiate, Ca2+‐dependent PC‐PLC and γ‐GT activities decreased significantly, together with α‐fetoprotein expression. There was a close relationship between Ca2+‐dependent PC‐PLC and γ‐GT activities during differentiation as there was during proliferation. We suppose that Ca2+‐dependent PC‐PLC is involved in rat hepatocarcinogenesis induced by DEN and that it plays an important role in the phorbol ester‐induced proliferation or retinoic acid‐induced differentiation of liver cancer cells.
PPRAS1 PPRAS2ANDPPRAP1GENES, MEMBERS OF ARASGENE FAMILY FROM THE TRUE SLIME MOLDPHYSARUM POLYCEPHALUMARE DEVELOPMENTALLY REGULATED
Authors: KOZLOWSKI PIOTR , TRZCINSKA‐DANIELEWICZ JOANNA , URBANCZYK AGNIESZKA , TOCZKO KAZIMIERZ
Published: October 2002

The expression patterns of two truerasgenes,Ppras1andPpras2and onerapgene,Pprap1were examined in fourPhysarum polycephalumdevelopmental stages: uninucleate amoebae, plasmodia (multinucleate syncytia), spherules (a vegetative, dormant stage) and fruiting bodies.Ppras1andPprap1are expressed in all stages examined with the maximum levels of their transcripts in amoebae and fruiting bodies, respectively, and the minimum levels in plasmodia, whereas thePpras2transcript is only detectable in amoebae and fruiting bodies. The results obtained indicate thatP. polycephalumis an organism possessing a developmentally regulatedrasgene family and presents a convenient system to study the role ofras/rapgenes in control of growth and differentiation of lower eukaryotic organisms.
HISTOCHEMISTRY OF OXIDASES IN SEVERAL TISSUES OF BIVALVE MOLLUSCS
Authors: CANCIO IBON , CAJARAVILLE MIREN P.
Published: October 2002

Various tissues of the marine bivalveMytilus galloprovincialiswere analysed histochemically for oxidases capable of generating reactive oxygen species (ROS) using the cerium‐DAB technique. Incubations were performed on unfixed cryostat sections using polyvinyl alcohol and semipermeable membranes. High xanthine oxidoreductase andd‐amino acid oxidase (DAOX) activities were observed in kidney epithelial cells of mussels. DAOX also presented a strong activity in all the digestive epithelia. No xanthine oxidase activity was observed in any of the mussel tissues tested suggesting the presence of an enzyme only showing dehydrogenase activity. Mannitol oxidase, associated with special organelles called ‘mannosomes’ of terrestrial gastropods, presented a weak activity in the stomach epithelium and a strong specific activity in the haemocytes. Only DAOX presented a discrete granular distribution compatible with a peroxisomal compartmentalization. No urate oxidase activity could be demonstrated in tissues of mussels. These observations suggest a role for peroxisomes in ROS generation and determine the tissues capable of producing oxygen radicals in the digestive gland. This study raises the question of the behaviour of these enzymes in conditions in which ROS‐generating organic xenobiotics are accumulated in the digestive gland of molluscs.
LOCALIZATION OF SH‐PTP1 TO SYNAPTIC VESICLES: A POSSIBLE ROLE IN NEUROTRANSMISSION
Authors: JENA BHANU P. , WEBSTER PAUL , GEIBEL JOHN P. , VAN DEN POL ANTHONY N. , SRITHARAN KUMUDESH C.
Published: October 2002

The tyrosine kinase pp60src is known to phosphorylate synaptophysin and in doing so may regulate neurotransmitter release. The tyrosyl phosphorylated state of synaptophysin is dependent on pp60src kinase and the unknown protein tyrosine phosphate phosphohydrolase (PTPase, EC 3.1.3.48). Here we report the protein tyrosine phosphate phosphohydrolase SH‐PTP1, to associate with synaptic vesicles and interact with synaptophysin. These studies identify SH‐PTP1 as a new member of the secretory machinery at the nerve terminal and suggest its involvement in neurotransmission.
MINI‐REVIEW/COMMENTARY
Authors: Mitchison J. M. , Novak B. , Sveiczer A.
Published: October 2002

This report is the first to describe the isolation of a 400 base pair cDNA clone encoding part of the bovine α1(IV) procollagen. Using the polymerase chain reaction (PCR), we have amplified a sequence of approximately 400bp from this gene within the recombinant phage DNA. The cloned sequence encodes 94 amino acids that form part of the protein's helical region. The sequence contains one interruption in the Gly‐Xaa‐Yaa repeat unit. The third base of the codon for glycine at several sites differs from those seen in murine and human genes, as does the third base of proline codons. The bovine cDNA also contains fewer thymine residues. Northern blot hybridization has shown that the mRNA for bovine procollagen to be 6.2kb in size. We have used the cDNA clone to investigate the effect of all‐transretinoic acid (RA) on the gene expression of α1(IV) procollagen in cultured bovine lens epithelial (LE) cells. We have also observed that RA decreases total protein production and concomitantly increases type IV procollagen in a concentration dependent manner. An increase in α1(IV)mRNA as well as increase in type IV procollagen suggest that the regulation of α1(IV) gene by RA in the LE cells is at the transcriptional level. Further, our results support the hypothesis that RA inhibition of lens epithelium transformation to fibroblast‐like cells may be due to the ability of RA to stimulate the production of basement membrane components by epithelia.
PROPIONIC ACID STIMULATES SUPEROXIDE GENERATION IN HUMAN NEUTROPHILS
Authors: NAKAO SUMI , MORIYA YOSHIKO , FURUYAMA SHUNSUKE , NIEDERMAN RICHARD , SUGIYA HIROSHI
Published: October 2002

Short‐chain carboxylic acids are the metabolic by‐products of pathogenic anaerobic bacteria and are found at sites of infection in millimolar quantities. We previously reported that propionic acid, one of the short‐chain carboxylic acids, induces an increase in intracellular Ca2+([Ca2+]i) in human neutrophils. Here we investigate the effect of propionic acid on superoxide generation in human neutrophils. Propionic acid (10mm) induced inositol 1,4,5‐trisphosphate (IP3) formation and a rapidly transient increase in [Ca2+]i, but not superoxide generation, whereas 1μm formylmethionyl‐leucyl‐phenylalanine (fMLP), a widely used neutrophil‐stimulating bacterial peptide, stimulated not only IP3formation and Ca2+mobilization but also superoxide generation. The IP3level induced by propionic acid was slightly lower than that induced by fMLP. The transient increase in [Ca2+]iinduced by propionic acid immediately returned to the basal level, whereas a sustained increase in [Ca2+]i, which was higher than the basal level, following a transient increase in [Ca2+]iwas induced by fMLP. The peak level induced by propionic acid was lower than that with fMLP. In the absence of extracellular Ca2+, thapsigargin, a potent inhibitor of endoplasmic reticulum Ca2+‐ATPase, induced an increase in [Ca2+]ieven after propionic acid stimulation, but not after fMLP. The Ca2+ionophore A23187 and thapsigargin induced superoxide generation by themselves. Propionic acid enhanced the superoxide generating effect of A23187 and thapsigargin. These results suggest that Ca2+mobilization induced by propionic acid is much weaker than that with fMLP, and propionic acid is able to generate superoxide in the presence of a Ca2+ionophore and a Ca2+influx activator.
ALTERED PHENOTYPIC CHARACTERISTICS OF T47D HUMAN BREAST CANCER CELLS AFTER PROLONGED GROWTH IN ESTROGEN‐DEFICIENT MEDIUM
Authors: Fernandez Pat , Wilson Cody , Hoivik Debie , Safe Stephen H.
Published: October 2002

T47D human breast cancer cells were cultured in estrogen‐deficient media for up to 32 months and the resulting cell line (L(hE−)) exhibited unique phenotypic and genotypic characteristics. Compared to low passage (L) cells, the L(hE−) cells exhibited a significantly higher rate of proliferation, unique morphological features, advanced ploidy status and 5‐ to 10‐fold higher levels of the estrogen receptor (ER) as determined by ligand binding and Western blot analysis. Sequence analysis of the DNA binding domain of the ER revealed a C→A transversion which resulted in a H513N amino acid change. Treatment of L cells with 10nm17β‐estradiol (E2) resulted in a greater than two‐fold increase in cell proliferation which was inhibited by tamoxifen, 4′‐hydroxytamoxifen, ICI 164,384 and ICI 182,780. In contrast, 10nmE2 caused a 70% decrease in growth of L(hE−) cells and this antimitogenic activity was blocked by ICI 164,384 and ICI 182,780 but not by tamoxifen or 4′‐hydroxytamoxifen. L(hE−) cells were E2‐responsive in transient transfection studies using a plasmid containing an estrogen‐responsive element derived from the vitellogenin A2 gene promoter. These data show that the phenotypic and genotypic characteristics of L(hE−) T47D cells resemble those described for ER‐negative cell lines stably transfected with the ER.
ANALYSIS OF p53‐DEPENDENT MECHANISMS IN THE MAINTENANCE OF GENETIC STABILITY IN DIPLOID TUMOURIGENIC LINE SK‐UT‐1B OF HUMAN UTERINE LEIOMYOSARCOMA
Authors: Smirnova Irina S. , Yakovleva Tatyana K. , Rosanov Yurii M. , Aksenov Nikolai D. , Pospelova Tatyana V.
Published: October 2002

The cells of tumourigenic line SK‐UT‐1B combine features characteristic both of normal (diploid karyotype, a low level of polyploid cells, absence of chromosomal marker) and tumour cells (high level of chromosomal instability, high malignancy). We suggest that maintenance of diploid karyotype in this line is controlled via the p53/p21 pathway. We demonstrate that the amount of p53 increases following γ‐irradiation and accumulated p53 protein seems to be functional as p53‐luc and p21/Waf‐luc reporter plasmids were found to be activated. However, γ‐irradiation‐induced increase of p53 was not accompanied by increase of p21/Waf on the protein level. Apparently this is one of the reasons for G1/S and G2/M checkpoint control disruption. The absence of these checkpoints could not prevent the proliferation of cells with intrachromosomal rearrangements. The only effective checkpoint in SK‐UT‐1B is the p53‐dependent M checkpoint, which directed the cells with changed chromosome numbers to apoptosis and therefore strictly guarded the diploidy of the cell population. This indicates that p53 can control the preservation of genetic stability at different levels via different pathways.
INTEGRINS AND STRETCH ACTIVATED ION CHANNELS; PUTATIVE COMPONENTS OF FUNCTIONAL CELL SURFACE MECHANORECEPTORS IN ARTICULAR CHONDROCYTES
Authors: Mobasheri A. , Carter S. D. , Martín‐Vasallo P. , Shakibaei M.
Published: October 2002

Perception of mechanical signals and the biological responses to such stimuli are fundamental properties of load bearing articular cartilage in diarthrodial joints. Chondrocytes utilize mechanical signals to synthesize an extracellular matrix capable of withstanding high loads and shear stresses. Recent studies have shown that chondrocytes undergo changes in shape and volume in a coordinated manner with load induced deformation of the matrix. These matrix changes, together with alterations in hydrostatic pressure, ionic and osmotic composition, interstitial fluid and streaming potentials are, in turn, perceived by chondrocytes. Chondrocyte responses to these stimuli are specific and well coordinated to bring about changes in gene expression, protein synthesis, matrix composition and ultimately biomechanical competence. In this hypothesis paper we propose a chondrocyte mechanoreceptor model incorporating key extracellular matrix macromolecules, integrins, mechanosensitive ion channels, the cytoskeleton and subcellular signal transduction pathways that maintain the chondrocyte phenotype, prevent chondrocyte apoptosis and regulate chondrocyte‐specific gene expression.
p53‐LIKE PROTEIN BINDING AFFINITY TO THE HORMONE RESPONSIVE ELEMENT OF THE HAPTOGLOBIN GENE IN FETAL RAT LIVER
Authors: Bogojević Desanka , Petrović Miodrag , Mihailović Mirjana
Published: October 2002

In order to identify nucleoproteins involved in transcriptional regulation of the haptoglobin (Hp) gene, fetal rat livers of dams exposed to inflammation on day 19 of pregnancy were used. Previously observed acute phase‐dependent elevation of Hp gene transcriptional activity in prenatal liver was accompanied by increased binding affinities of several fetal soluble nucleoproteins and the hormone response element (RE) of the Hp gene (‐170/‐56). One of these proteins, a hepatic nucleoprotein of 53kDa, was identified by Western blotting analysis as a protein within the same molecular mass and epitopes as transcription factor p53. Also, in vitro phosphorylation experiments revealed that the examined fetal nucleoprotein could be liable to the same phosphorylative post‐translational modification as p53. The obtained results suggest that the fetal 53kDa‐nucleoprotein could be a homologue of transcription factor p53, participating in the transcriptional modulation of the Hp gene throughout prenatal hepatic development.
THE COUPLING OF VINCULIN TO THE CYTOSKELETON IS NOT ESSENTIAL FOR MECHANO‐CHEMICAL SIGNALING IN F9 CELLS
Authors: Goldmann Wolfgang H.
Published: October 2002

It is well established that mechanical forces can regulate cell growth and guide tissue remodeling, yet little is known about how mechanical signals act at the cell surface membrane to produce biochemical changes in the cell. To explore this question, I used a mouse embryonic F9 vinculin‐deficient cell line (γ229), which, unlike wild‐type cells, shows no fibronectin‐dependent cell spreading. The wild‐type cell line exhibited a twofold increase in area over four hours. I observed (i) an earlier rise in intracellular free calcium from ∼0.2 to ∼3μm in wild‐type compared with γ229 cells, thus similar calcium levels after 4h; (ii) an initial higher ratio of p‐MAP/MAP‐Kinase for γ229, but similar FA‐Kinase activation; and (iii) a marginal change in intracellular pH [pH]i in both F9 cell lines. When I applied controlled local stresses directly to integrin receptors using RGD‐coated magnetic beads, they displaced to a lesser extent in wild‐type than in γ229 cells. Both F9 cell lines showed a small stress‐dependent rise in [Ca2+]i levels and similar PKA‐c activity. In summary, the mechanical linkage of integrin‐vinculin‐cytoskeleton seemed not to be essential for chemical signal transduction.
OVER‐EXPRESSION OF K‐FGF OR bFGF RESULTS IN ALTERED EXPRESSION OF MATRIX METALLOPROTEINASES: CORRELATIONS WITH MALIGNANT PROGRESSION AND CELLULAR INVASION
Authors: Lo James , Hurta Robert A. R.
Published: October 2002

Matrix metalloproteinase (MMP) expression was investigated in NIH‐3T3 fibroblasts that secrete K‐FGF and in NIH‐3T3 cells which express chimeric bFGF with a signal sequence targeting bFGF to the secretory pathway. Correlations between altered MMPs' and other proteases' expression and malignant potential were determined. Correlations between the expression of MMPs and the invasion ability of K‐FGF and bFGF over‐expressing cells were also determined. The resulting correlation between alterations in proteases and malignant progression supports a model which suggests that growth factor modulation of protease expression is part of the altered growth regulatory program associated with cellular transformation and malignant progression.
CHANGES IN FUSED CELLS INDUCED BY HVJ (SENDAI VIRUS): REDISTRIBUTION OF CYTOPLASMIC ORGANELLES AND CYTOSKELETAL REORGANIZATION
Authors: Hirayama Etsuko , Ama Masako , Takahashi Ken‐Ichiro , Hiraki Akihiro , Kim Jeman
Published: October 2002

To understand the relationship between the location of organelles and cellular function, we examined the dynamic state of cytoplasmic organelles and cytoskeleton in polynuclear Ehrlich ascites tumor (EAT) cells fused with hemagglutinating virus of Japan (HVJ; Sendai virus) by confocal laser scanning microscopy. Irregular fused cells gradually became spherical during culture, and nuclei and mitochondria were redistributed in the fused cell; nuclei formed a cluster surrounded by mitochondria. F‐actin, vimentin, and microtubules were also reorganized with the redistribution of cell organelles. Further, when the morphological change was inhibited by L4‐1, a chlorophyll‐like substance derived from silkworm faeces, or pyropheophorbide‐a, the arrangement of organelles and cytoskeleton remained disturbed, suggesting that the movement of the cytoskeleton is closely associated with cell shape and the distribution of cytoplasmic organelles.
CHANGES IN FUSED CELLS INDUCED BY HVJ (SENDAI VIRUS): RELATIONSHIP OF MORPHOLOGICAL CHANGES TO ENDOCYTOSIS OF THE SURFACE MEMBRANE
Authors: Ama Masako , Hirayama Etsuko , Hiraki Akihiro , Kim Jeman
Published: October 2002

Fused Ehlrich ascites tumor (EAT) cells induced by hemagglutinating virus of Japan (HVJ; Sendai virus) had an irregular shape, reflecting the shape of cell aggregates before fusion. During subsequent culture, the fused cells gradually took on a spherical form within 60min. Examination of the fused cells revealed a vigorous endocytosis of the cell membrane during the morphological change. When EAT cells were treated with porphyrin derivatives, and the morphological change to a spherical form was inhibited, endocytosis of fused cells was also suppressed, suggesting that the change is closely associated with endocytotic activity. Further examination with porphyrin derivatives and hydrogen peroxide suggested that the inhibition of morphological change is due to the suppression of endocytosis by active oxygen species produced by these substances. Experiments using an endocytotic inhibitor, methylamine, indicated that endocytosis is essential for the morphological change that occurs in the fused cells.
THE CARBOXY‐TERMINUS OF PROTEIN 4.1R RESEMBLES BETA‐TUBULIN
Authors: Fant Xavier , Merdes Andreas
Published: October 2002

The protein 4.1R is an isoform of a larger family of 4.1 proteins. It is known as a component of the plasma membrane skeleton, but it is also found at the centrosomes in interphase and mitosis. To investigate the properties of the carboxy terminal region of protein 4.1R, we raised antibodies against a peptide representing the last 14 amino acids of 4.1R. These antibodies crossreact with an epitope in beta‐tubulin and stain the microtubule network by immunofluorescence. Furthermore, sequence comparison of the carboxy terminal 4.1R peptide sequence with tubulin reveals homology with a region at the end of helix 5 in beta‐tubulin, but not alpha‐tubulin. A potential function of the 4.1R carboxy terminus in regulating the formation of microtubule networks is discussed.
IMMUNOSPECIFIC PROTEIN OF 34.5kDa FROM DNA—PROTEIN CROSS‐LINKS INDUCED BY CIS ‐ ANDTRANS ‐DIAMMINEDICHLOROPLATINUM
Authors: Woźniak Katarzyna , Walter Zofia
Published: October 2002

Cis ‐diamminedichloroplatinum(II) (cis ‐DDP) is one of the most often used anticancer drugs. It is generally accepted that the antitumor activity of the drug results from its interactions with DNA. Trans ‐diamminedichloroplatinum(II) (trans ‐DDP) also binds to DNA effectively, but is clinically ineffective. In the present work the lymphocyte nuclear proteins that participate in DNA—protein cross‐links induced by cis ‐ and trans ‐DDP are investigated. In lymphocytes which are incubated without platinum compounds there are DNA‐binding proteins in the range of 45–71kDa. It is shown that additional proteins of 28, 30, 34.5, 45 and 120kDa are cross‐linked with DNA in lymphocytes after 2‐h incubation with cis ‐DDP at concentrations of 0.1 and 0.5mM. Trans ‐DDP does not bind additional proteins to DNA after the same incubation time. Electrophoretic analysis shows that trans ‐DDP binds much more of the same nuclear proteins to DNA than cis ‐DDP after 12‐h incubation. In this study a test for the identification of 34.5kDa protein is also undertaken. This protein appears in the samples obtained after 12‐h incubation of lymphocytes with cis ‐ and trans ‐DDP at 0.5 and 1mM, especially. The protein of 34.5kDa from cross‐links induced by 1mM trans ‐DDP is recognized by antibodies against the protein of the same molecular weight from the nuclear matrix of the lymphocytes. The results obtained here are discussed in relation to the biological activity of diamminedichloroplatinum isomers.
DNA TOPOISOMERASE ACTIVITIES IN CHINESE HAMSTER RADIOSENSITIVE MUTANTS AFTER X‐RAY TREATMENT
Authors: Pastor Nuria , Cortés Felipe
Published: October 2002

In the last years the attractive hypothesis of a possible involvement of mammalian topoisomerases in DNA repair has been proposed, given their molecular mechanism of action. So far, using asynchronous cultures a lot of controversial results have been reported, without taking into account the frequently dramatic fluctuations of topoisomerase activities depending upon the cell cycle stage and proliferation rate (mainly for topoisomerase II).

We have addressed this question making use of G1 synchronous cultures of the Chinese hamster radiosensitive mutants xrs 5 (defective in DNA double strand breaks rejoining) and irs 2 (which shows radioresistant DNA synthesis), as well as their parental lines CHO K1 and V79 respectively, which show a normal radiosensitivity. Cells were irradiated with 5Gy of X‐rays and the activities of topoisomerases I and II in nuclear extracts were studied for comparison with non‐irradiated controls in both the mutants and parental cell lines.

Our results clearly show a modulation of the topoisomerase activities after irradiation, that varies depending upon the mutation that the different lines bear.

While this hypothesis needs further testing, an interesting idea is that DNA topoisomerases might be involved in the cellular response to radiation damage, either through a direct participation in the repair mechanisms or in a preparative step to allow repair to proceed.
MONOCYTES MODULATE THE IN VITRO BASAL FREQUENCY OF SISTER CHROMATID EXCHANGES OF PLASMA LEUKOCYTE CULTURES AND MITOTIC ACTIVITY OF SUPPRESSOR‐CYTOTOXIC T8 HUMAN LYMPHOCYTES
Authors: Soloneski Sonia M. , Reigosa Miguel A. , Garcia Carlos F. , Larramendy Marcelo L.
Published: October 2002

The effect of monocytes (MNs) on baseline SCEs and kinetics of human lymphocytes in plasma leukocyte (PLCs) and whole blood cultures (WBCs) was studied. Baseline SCEs in PLCs were nearly two‐fold over WBCs. No differences in SCEs were observed between PLCs and MN‐depleted PLCs, indicating that SCEs from PLCs are independent of MNs. MNs titration into PLCs decreased proportionally SCEs. Reconstitution of depleted PLCs with concentration of MNs equivalent or higher than those of PLC decreased SCEs. No variations of lymphocyte kinetics in PLCs were observed in the absence/presence of MNs. The proportion of B and T‐cell subsets among interphasic lymphocytes were similar in PLC in the absence/presence of MNs, but a significant increase in the proportion of mitotic T8 lymphocytes was observed. Accordingly, MNs modulate both the in vitro basal SCEs and the mitotic activity of T8, but not their cell‐cycle kinetics.
Late Pleistocene Glaciation of Mono Basin, California
Authors: Bursik Marcus I. , Gillespie Alan R.
Published: October 2002

Moraines in the canyons of Mono Basin are separable into relative-age groups on the basis of clast-sound velocities in exposed boulders, moraine morphology, and weathering features on boulder surfaces. Tioga, Tenaya, Tahoe, and Mono Basin moraine deposits each have distinct weathering characteristics and therefore constitute different relative-age groups. The Tioga glacial episode at June Lake may postdate ∼25,200(?)-yr-old basaltic lavas, and the Tenaya episode may have occurred ∼30,700 yr ago. A comparison of the glacial and lacustrine records of Mono Basin over the past 40,000 yr, based on new interpretations of radiometric ages, is consistent with the hypothesis that maximum glacial and maximum pluvial periods were not necessarily synchronous.
Age Constraints on the Duck Ponds and Limeburner's Point Mammalian Faunas Based on Magnetic Polarity Stratigraphy in the Geelong Area (Victoria), Australia
Authors: Whitelaw Michael John
Published: October 2002

New magnetostratigraphic results may be used to determine the age of two locally important fossil vertebrate faunas near Geelong (Victoria), Australia. Paleomagnetic samples collected from sections located at Limeburner's Point and Limeburner's Bay, together with previously suggested stratigraphic correlations, now constrain the age of the Duck Ponds Local Fauna to be younger than 1.66 myr (and probably greater than 0.98 myr) and the age of the Limeburner's Point Local Fauna to be younger than 0.98 myr. These age determinations enhance the biostratigraphic importance of both local faunas on a continent characterized by a chronic lack of chronologically well-constrained fossil vertebrate localities.
Soil Development Parameters in the Absence of a Chronosequence in a Glaciated Basin of the White Mountains, California-Nevada
Authors: Swanson Terry W. , Elliott-Fisk Deborah L. , Southard Randel J.
Published: October 2002

Detailed mapping and provisional numerical age determinations of glacial deposits in the South Chiatovich Creek Basin of the White Mountains provide an opportunity to evaluate the ability of conventional soil parameters to discriminate first- and second-order glacial events. Sampling and analytical procedures were designed to minimize variation in climate and lithology. When lithology and climate are similar among sites, age trends are more pronounced in both field and chemical soil properties. Profile development indices (PDIs), adjusted by removing melanization and pH, systematically increase with greater soil age, and discriminate first-order, but not second-order, glacial events. The best-fit curve for adjusted PDI data assumes an exponential form and suggests that the rate of soil formation in this region decreases over time, similar to the rate of weathering-rind development. Variation in eolian influx and surface erosion, which are dominant processes affecting soils of the basin, cause major uncertainties in establishing soil age and, hence, soil-development rates. Even on the youngest glacial deposits, soil age is probably significantly less than deposit age due to these geomorphic processes. Soil and weathering parameters imply that these field techniques can be inexpensively employed to define relative chronologies and to assess surface degradation and its impact on surface exposure ages. Results from this study indicate that site-selection strategy for establishing glacial chronologies should be reevaluated. Working with stable residual bedrock surfaces and associated low-relief outwash fans and terraces may prove more productive than focusing on relatively unstable moraine surfaces in tectonically active mountain systems.
Hemipelagic Sediment Accumulation Rates in the South China Sea Related to Late Quaternary Sea-Level Changes
Authors: Schönfeld Joachim , Kudrass Hermann-Rudolf
Published: October 2002

Sediments of 13 piston cores from opposite continental slopes of the South China Sea, off southern China and Sabah (northern Borneo), were analyzed by sedimentological methods and dated by oxygen isotope stratigraphy. Sediments mostly consist of hemipelagic clay with 20% carbonate off Sabah and 40% off China. We calculated terrigenous and carbonate accumulation rates for up to 11 time-slices from the Holocene to oxygen-isotope stage 6. Terrigenous accumulation rates generally increase with water depth and reach a maximum at the middle slope off Sabah and at the lower continental slope off China. During glacial and interglacial times this distribution pattern did not markedly change, despite an increase of accumulation rates for glacial periods by a factor of 2 to 5 compared to interglacial periods. Rates are negatively correlated with positions of sea level, which controls the partition of fluviatile terrigenous material for deposition on shelf, slope, and abyssal plain. Carbonate accumulation rates are higher off China by a factor of 2 compared to Sabah, probably indicating higher calcareous plankton productivity.
Uranium-Series Ages of Marine Terrace Corals from the Pacific Coast of North America and Implications for Last-Interglacial Sea Level History
Authors: Muhs Daniel R. , Kennedy George L. , Rockwell Thomas K.
Published: October 2002

Few of the marine terraces along the Pacific coast of North America have been dated using uranium-series techniques. Ten terrace sequences from southern Oregon to southern Baja California Sur have yielded fossil corals in quantities suitable for U-series dating by alpha spectrometry. U-series-dated terraces representing the ∼80,000 yr sea-level high stand are identified in five areas (Bandon, Oregon; Point Arena, San Nicolas Island, and Point Loma, California; and Punta Banda, Baja California); terraces representing the ∼125,000 yr sea-level high stand are identified in eight areas (Cayucos, San Luis Obispo Bay, San Nicolas Island, San Clemente Island, and Point Loma, California; Punta Bands and Isla Guadalupe, Baja California; and Cabo Pulmo, Baja California Sur). On San Nicolas Island, Point Loma, and Punta Bands, both the ∼80,000 and the ∼125,000 yr terraces are dated. Terraces that may represent the ∼105,000 sea-level high stand are rarely preserved and none has yielded corals for U-series dating. Similarity of coral ages from midlatitude, erosional marine terraces with coral ages from emergent, constructional reefs on tropical coastlines suggests a common forcing mechanism, namely glacioeustatically controlled fluctuations in sea level superimposed on steady tectonic uplift. The low marine terrace dated at ∼125,000 yr on Isla Guadalupe, Baja California, presumed to be tectonically stable, supports evidence from other localities for a +6-m sea level at that time. Data from the Pacific Coast and a compilation of data from other coasts indicate that sea levels at ∼80,000 and ∼105,000 yr may have been closer to present sea level (within a few meters) than previous studies have suggested.
First Radiocarbon Dates for San Josecito Cave, Nuevo León, México
Authors: Arroyo-Cabrales Joaquı́n , Johnson Eileen , Haas Herbert , De Los Rı́os-Paredes Magdalena , Ralph Ronald W. , Hartwell William T.
Published: October 2002

Initial excavations (1935-1941) in San Josecito Cave, Nuevo León, México revealed a rich late Quaternary fossil fauna. The San Josecito Cave fauna was viewed as a single time-related entity despite the lack of 14C dating. Renewed excavations (1990) recovered a series of 14 C samples related to the complex stratigraphy. Six 14C dates show that the recently excavated deposits range in age between 45,000 and 27,000 yr B.P. These ages suggest that the upper deposits, removed in the earlier excavations, date from 27,000 to 11,000 yr B.P.
Postglacial Vegetation and Climate Change in the Northern Bristol Bay Region, Southwestern Alaska
Authors: Hu Feng Sheng , Brubaker Linda B. , Anderson Patricia M.
Published: October 2002

Pollen analysis of sediment cores from Grandfather and Ongivinuk Lakes reveals a record of postglacial vegetation and climate change in the northern Bristol Bay region. The chronology is based on six conventional14C dates of bulk organic matter from the Grandfather core. A mesic herb tundra dominated the landscape 13,000-9800 yr B.P.Betulashrubs probably first appeared in the region 11,300 yr B.P. but were restricted to favorable microhabitats until 9800 yr B.P. The later establishment ofBetulashrubs and relatively lowBetulapollen abundance in these records compared to other areas of eastern Beringia suggest that postglacial warming in southwestern Alaska was dampened by regional climatic controls, possibly low sea-surface temperatures of the North Pacific Ocean. Between 10,800 and 9800 yr B.P., diminishedBetulashrub cover, along with decreased aquatic productivity as recorded byPediastrumcell nets and biogenic silica, suggest a brief reversion to colder and drier climatic conditions possibly associated with the Younger Dryas event. Around 9800 yr B.P.,Betulashrub tundra and meadow communities expanded, probably in response to increased temperature and precipitation.Alnusarrived and formed extensive thickets within the region ca. 7400 yr B.P. The establishment of the modern boreal forest-tundra ecotone is marked by the arrival ofPicea glaucaat Grandfather Lake ca. 4000 yr B.P. and the subsequent increase to present population densities ca. 2000 yr B.P. The unique features of these pollen records emphasize the spatial complexity of late Quaternary vegetation and climate history in eastern Beringia.
Chronology of Holocene Cheniers and Oyster Reefs on the Coast of Bohai Bay, China
Authors: Wang Hong , Van Strydonck Mark
Published: October 2002

Cheniers and oyster reefs are two essential components of Holocene strata on the coast of Bohai Bay, China. The existing nonconventional14C dates, often with unsuitable sample positions, less-tested samples, and unreasonable data comparisons, limit the refined analysis of the local chronostratigraphy. On the basis of a number of pretreatment routines, including geological investigations, X-ray diffraction analysis (XRD), δ13C measurement of shells, selection of appropriate shell species (Umboniumsp. and Terebridae) for14C dating, and determination of the local mean δ13C value (−2.68‰ PDB) for the common shells, a set of samples was radiocarbon-dated by Accelerator Mass Spectrometry (AMS). These new ages, obtained from the lower part of cheniers, enable us to estimate the initiation of the cheniers, and confirm that the existing nonconventional dates are often questionable due to unsuitable sample positions. Another two AMS ages, dated for two different microgrowth layers, precipitated in a varying water body, of the sameCrassostrea gigasshell are statistically identical within 2σ error. This implies that the different water masses in the coastal environment would be rapidly in balance with the contemporaneous atmospheric CO2. Both MARINE93 and INTERCAL93 were used for calibration of radiocarbon dates. These amended the time frame of the local Holocene history.
The Timing and Environmental Significance of Late Quaternary Linear Dune Development in Western Zambia
Authors: O'Connor Peter W. , Thomas David S. G.
Published: October 2002

Optical luminescence dates for 19 samples from the degraded linear dune field of western Zambia indicate multiple periods of regional dune building for the late Quaternary, 32,000–27,000, 16,000–13,000, 10,000–8000, and 5000–4000 yr ago. These dates show that the last glacial maximum was not the only time when dune construction, commonly linked to marked aridity, occurred in central-southern Africa during the late Quaternary. Whereas rainfall significantly less than today's ca. 1400 mm yr−1is a prerequisite for dune construction in the area, adequate sediment supply also determines dune construction and preservation, so that dune building cannot be simply and singularly linked to marked aridity. The Zambezi River system is proposed as an important source of dune sediments, with the nature of linear dune activity explaining why stacked sediments preserve several phases of dune formation. Chronologies of dune construction in western Zimbabwe and the southwest Kalahari are in broad agreement with our Zambian chronology and support a model of rainfall shifts along a SW–NE gradient, with some notable disparities. These are probably a function of interregional sediment supply differences, the number of samples used to delimit constructional periods, and the multicausal nature of forcing mechanisms.
Extent and Dynamics of the Scandinavian Ice Sheet during Oxygen Isotope Stage 3 (65,000–25,000 yr B.P.)
Authors: Arnold Neil S. , van Andel Tjeerd H. , Valen Vidar
Published: October 2002

The climate of the middle Weichselian Glaciation, Marine Oxygen Isotope Stage 3 (OIS-3), a relatively mild period compared to the glacial maxima of OIS-4 and OIS-2, consisted of long warm interstades punctuated by brief cold excursions that grew colder and more frequent with time. The OIS-4 ice sheet is generally thought to have persisted throughout OIS-3, but evidence from dated OIS-3 interstadial deposits suggests that it was swiftly reduced to small remnants which only briefly expanded and retreated. Only 30,000 years ago the deteriorating climate initiated a sustained ice advance leading toward the final glacial maximum of OIS-2. Dynamic ice-sheet models support the existence of a prolonged ice-free interval during OIS-3 induced, perhaps, by low precipitation due to extensive sea-ice cover offshore.
The Formalization of a Cognitive Architecture and its Application to Reasoning About Human Computer Interaction
Authors: Duke David , Duce David
Published: October 2002

Software systems are not just mathematical structures. The majority are also cognitive artefacts that rely on the ability of their users to understand and interpret information provided via an interface, and to act on that information using actions provided by the system. The design of an interactive system must thus account for both the technical requirements of the given domain, and the cognitive abilities of the user. However, the disciplines involved (computer science and psychology) traditionally operate with quite different methods and techniques, making it difficult to integrate their respective insights into system design. This paper reports on work that is creating a framework for interaction that encompasses both the description of complex software systems and the cognitive resources needed to operate those systems. An interface for supporting gestural interaction is used to illustrate the approach. The paper concludes with
an assessment of the prospects for this kind of integrative modeling and sets out key areas for future progress.