bluuebunny/crossref_metadata_2025 huggingface dataset:
Acetylation of α‐tubilin in different bovine cell types: implications for microtubule dynamics in interphase and mitosis.
Authors: Wolf Klaus Werner , Spanel‐Borowski Katharina
Published: October 2002

Previous work on five cell types isolated from the bovine corpus luteum showed that the mass of acetylated microtubules (acet‐MTs) in interphase differed. Endothelial cells, termed type 3, showed few acet‐MTs, whereas the interphase cytoskeleton of granulosal‐like cells, termed type 5, was rich in acet‐MTs. In the present study, these cultured cells were used to determine whether the degree of α‐tubulin acetylation in interphase had consequences on mitosis. To this end, the distribution of acet‐MTs was determined throughout the cell cycle using a monoclonal antibody, 6‐11B‐1, directed against acetylated α‐tubulin. For comparison, tyrosinated MTs were visualized with another monoclonal antibody, YL1/2, detecting tyrosinated α‐tubulin. Although the amount of acet‐MTs in interphase differed significantly between both cell types, major differences in the appearance of acet‐MTs during mitosis were only apparent in prophase and during transition from late telophase to interphase. Thus, irrespective of different α‐tubulin acetylation in interphase, spindle structure is uniform. Since acetylation of α‐tubulin is believed to indicate the presence of relatively stable MTs, we conclude that MT dynamics is differently controlled in interphase and mitosis. Thereby interphase cells are able to carry out functions which involve stable MTs and the cells progress through mitosis in the presence of more dynamic MTs.
Oxidative stress and the development of diabetic complications ‐ antioxidants and lipid peroxidation in erythrocytes and cell membrane.
Authors: Parthiban Anusha , Vijayalingam Selvamani , Shanmugasundaram K. Radha , Mohan Rema
Published: October 2002

Erythrocytes isolated from 131 cases of Non‐Insulin Dependent Diabetes Mellitus (NIDDM) were studied for lipid peroxidation, antioxidant defences, and the maximum peroxidisable substrate in the cell membrane. Antioxidant defences are lowered in NIDDM, followed by significant rise in lipid peroxidation products. However, in the erythrocyte membrane, the total polyunsaturated peroxidisable lipids are lower than in normal erythrocytes which may be a causative factor affecting the survival of the cells.
EFFECTS OF DIPEPTIDES CONTAINING THE AMINO ACID, PROLINE ON THE CHEMOTAXIS OF TETRAHYMENA PYRIFORMIS. EVOLUTIONARY CONCLUSIONS ON THE FORMATION OF HORMONE RECEPTORS AND HORMONES
Authors: KÖHIDAI LÁSZLÓ , SOÓS PÁL , CSABA GYÖRGY
Published: October 2002

Our investigations demonstrate that proline‐containing dipeptides can provoke a chemosensory response from the unicellular Tetrahymena pyriformis The chemotactic effects of the dipeptides have a close relationship with the side chain and the lipophilicity of the amino‐terminal amino acid. Comparison of ‘mirror’ variants of proline‐containing dipeptides points to the fact that dipeptides with small side chain and non‐polar character amino acids (Gly‐Pro, Ala‐Pro) are preferred on the amino‐terminal end. In the case of amino acids with very variable side chains, small (Pro‐Gly) and the large side chain and non‐polar character amino acids (Pro‐Leu, Pro‐Phe) on the carboxyl‐terminal end can induce significant chemotactic responses. With valine on any terminus the proline‐containing dipeptide induced a weak repellent effect.
RAPID ALDOSTERONE‐INDUCED CELL VOLUME INCREASE OF ENDOTHELIAL CELLS MEASURED BY THE ATOMIC FORCE MICROSCOPE
Authors: SCHNEIDER STEFAN W. , YANO YOSHIKO , SUMPIO BAUER E. , JENA BHANU P. , GEIBEL JOHN P. , GEKLE MICHAEL , OBERLEITHNER HANS
Published: October 2002

Atomic force microscopy (AFM) is a useful technique for imaging the surface of living cells in three dimensions. The authors applied AFM to obtain morphological information of individual cultured endothelial cells of bovine aorta under stationary and strain conditions and to simultaneously measure changes in cell volume in response to aldosterone. This mineralocorticoid hormone is known to have acute, non‐genomic effects on intracellular pH, intracellular electrolytes and inositol‐1,4,5‐triphosphate production. In this study whether endothelial cells under tension change their volume in response to aldosterone was tested. Such changes were already shown in human leukocytes measured by Coulter counter. In contrast to leukocytes that are more or less spherical and live in suspension, endothelial cells exhibit a complex morphology and adhere to a substrate. Thus, measurements of discrete cell volume changes in endothelial cells under physiological condition is only feasible with more sophisticated techniques. By using AFM we could precisely measure the absolute cell volume of individual living endothelial cells. Before the addition of aldosterone the cell volume of mechanically stressed endothelial cells mimicking arterial blood pressure was 1827±172fl. Cell volume was found to increase by 28% 5min after hormone exposure. Twenty‐five minutes later cell volume was back to normal despite the continuous presence of aldosterone in the medium. Amiloride, a blocker of the plasma membrane Na+/H+exchanger prevented the initial aldosterone‐induced volume increase. Taken together, AFM disclosed a transient swelling of endothelial cells induced by the activation of an aldosterone sensitive plasma membrane Na+/H+exchanger.
OSTEOGENESIS IN VITRO IN RAT TIBIA‐DERIVED OSTEOBLASTS IS PROMOTED BY THE HOMEOPATHIC PREPARATION, FMS*CALCIUMFLUOR
Authors: Palermo Claudia , Filanti Cristina , Poggi Silvia , Manduca Paola
Published: October 2002

We studied the effects of in vitro treatment of differentiating osteogenic cells with FMS*Calciumfluor, to determine whether it caused changes in proliferative or differentiation potential of osteoblasts. FMS*Calciumfluor was developed for the therapy of post‐menopausal and age‐related osteoporosis on the basis of the principles of resonance homeopathy and VTR Vega test. Its daily prescribed therapeutical usage is about 30,000‐fold less in fluoride concentration than that recommended for NaF associated with calcium monophosphate. Rat tibial osteoblast (ROB) primary cultures represent populations of early osteoblasts and their derivative cultures of more than 60 cumulative population doubling (CPD) represent more mature osteogenic cells. Both these populations were shown to undergo in vitro differentiation, as monitored by the sequential expression of markers that define the stages of the osteogenic progression. Here we report that continual treatment of ROB during osteogenesis with FMS*Calciumfluor modulated the expression of critical osteogenic markers: alkaline phosphatase (AP), an indicator of osteoblast maturation, and45Ca incorporation into the matrix and nodule formation, events of the last phase of osteogenesis and a measure of osteoid mineralization. Treatment did not affect proliferation, or expression and activation of metalloproteinases (MMP). AP activity and levels of AP mRNA were increased by treatment with FMS*Calciumfluor; the incorporation of radiolabelled Ca into the matrix was also increased and the formation of nodules occurred in a shorter time and with higher frequency than in untreated control cultures. The effects of FMS*Calciumfluor were concentration dependent and specific for its modalities of preparation, and were observed at a concentration about three orders of magnitude lower than similar effects reported in the literature by treatment of osteoblast cultures in vitro with NaF.
HEPATOCYTE GROWTH FACTOR SUPPORTS ANDROGEN STIMULATION OF GROWTH OF MOUSE VENTRAL PROSTATE EPITHELIAL CELLS IN COLLAGEN GEL MATRIX CULTURE
Authors: Sasaki Masato , Enami Jumpei
Published: October 2002

To assess the role of hepatocyte growth factor (HGF) and androgen in growth of prostate epithelial cells, we isolated mouse ventral prostate epithelial cells and cultured them in a three‐dimensional type I collagen gel matrix under serum‐free conditions. Although the prostate epithelial cells tended to die in the insulin‐supplemented basal medium, 5α‐dihydrotestosterone (DHT) prevented the cell death, and HGF slightly stimulated the growth. By contrast, coexistence of DHT and HGF greatly augmented the growth and branching morphogenesis of the epithelial cells. Some of the outgrowths formed under these conditions showed enlarged structures resembling the prostate ducts or alveoli. Examination of the stromal cell‐conditioned medium revealed that a growth‐stimulating activity is present in the conditioned medium. A major portion of this activity was abolished by anti‐HGF IgG. These observations suggest that HGF is produced by the stromal cells of the prostate gland and supports the androgen stimulation of growth of the epithelial cells.
PLD1b IN IIC9 FIBROBLASTS IS SELECTIVELY ACTIVATED IN THE NUCLEUS AND NOT IN THE GOLGI APPARATUS
Authors: Baldassare Joseph J. , Klaus Johanna , Phillips Polly J. , Raben Daniel M.
Published: October 2002

Mitogen‐induced activation of a nuclear‐acting PC‐phospholipase D (PLD) is mediated, at least in part, by the translocation of RhoA to the nucleus. A remaining question is whether PLD in all subcellular compartments is regulated in the same manner. To address this question, we identified PLD in another subcellular compartment and determined whether its activity was influenced by α‐thrombin in a RhoA‐dependent manner.

The data in this manuscript show that nuclear PLD is selectively regulated. α‐Thrombin stimulates an increase in PLD activity in IIC9 fibroblast nuclei while Golgi PLD activity is unaffected. We cloned PLD1 from IIC9s (hamPLD1b) to show that it is present in both nuclei and Golgi. Interestingly, only nuclear PLD1 is modulated by α‐thrombin, demonstrating that this activity is selectively regulated. These data provide support for the physiological importance of agonist‐induced nuclear signalling enzymes.
MECHANISMS OF THE INDUCTION OF APOPTOSIS IN HUMAN HEPATOMA CELLS BY TUMOUR NECROSIS FACTOR‐α
Authors: Li Jianfeng , Zheng Rongliang , Li Ji , Wang Zhenhua
Published: October 2002

Tumour necrosis factor alpha (TNF‐α) at 20ng/ml induced apoptosis in human hepatoma cellsin vitro. The effect of TNF‐α‐induced apoptosis was exacerbated by the hypoxanthine‐xanthine oxidase (HX/XO) system and cycloheximide (CHX), but alleviated by superoxide dismutase (SOD), suggesting that TNF‐α‐induced apoptosis may be due to oxidative stress, and independent of protein synthesis. TNF‐α elevated free Ca2+concentration, triggered lipid peroxidation and decreased the expression of bcl‐2 protein. The findings suggest that TNF‐α‐induced apoptosis may be involved in stimulating Ca2+‐dependent endonuclease activity and increasing membrane lipid peroxidation. Bcl‐2 may play a pivotal role in serving as a Ca2+regulator or antioxidant, preventing lipid peroxidation in the process.
NEW EVIDENCE THAT NUCLEAR IMPORT OF ENDOGENOUS β‐CATENIN IS LEF‐1 DEPENDENT, WHILE LEF‐1 INDEPENDENT IMPORT OF EXOGENOUS β‐CATENIN LEADS TO NUCLEAR ABNORMALITIES
Authors: Kim Kwonseop , Hay Elizabeth D.
Published: October 2002

The once accepted idea that LEF‐1 transports β‐catenin into nuclei has recently been challenged by experiments using exogenous β‐catenin. Here, we investigated the effects of β‐catenin and LEF‐1 on nuclear import of β‐catenin using different combinations of exogenous and endogenous molecules over longer lengths of time than previously studied. Nuclear β‐catenin is not detectable in corneal fibroblasts and epithelia or NIH 3T3 and MDCK cells. In LEF‐1 transfections, we show that the B‐box of LEF‐1 is required to move cytoplasmic endogenous β‐catenin into the nuclei of such cells, proving that LEF‐1 does transport endogenous β‐catenin into nuclei. Moreover, transfection of uveal melanoma cells with B‐box deficient LEF‐1 inhibits nuclear import of β‐catenin by endogenous LEF‐1. However, the movement of overexpressed exogenous β‐catenin into nuclei is unaffected by the presence or absence of LEF‐1 and forms abnormal nuclear aggregates that are a prelude to subsequent apoptosis. We conclude that nuclear transport of exogenous β‐catenin independently of LEF‐1 has questionable physiological significance.
IN VITRO MORPHOGENESIS OF AMPHIBIAN ERYTHROBLASTS
Authors: Huang Li‐Fang , Levinhar Liat , Ginsburg Mary , Lee Kyeng‐Gea , Cohen William D.
Published: October 2002

Non‐mammalian vertebrate erythrocytes are flattened nucleated ellipsoids containing marginal bands (MBs) of microtubules that assemble during cellular morphogenesis. Earlier work suggested that pointed erythroid cells containing pointed MBs were intermediate stages in terminal differentiation, rather than aberrant forms, but direct evidence was lacking. Here we report on morphogenesis in individual post‐cytokinetic amphibian erythroblasts in culture. Daughter cells remained adjacent in pairs, and developed pointed morphology over 1–2h in the following sequence: (a) ends opposite the cytokinetic furrow became pointed, producing a spheroidal singly‐pointed stage; (b) furrow ends usually became pointed, yielding doubly‐pointed cells; (c) furrow‐end points disappeared, producing a second singly‐pointed stage that was flattening. Over a longer term, the single points sometimes disappeared, yielding a flattened discoid. These observations support the hypothesis that pointed cells are normal intermediates in a biogenetic program in which post‐mitotic centrosomes organize MBs while occupying the singly‐pointed ends of differentiating erythroblasts.
ULTRAVIOLET B IRRADIATION MODULATES SUSCEPTIBILITY TO TUMOUR NECROSIS FACTOR‐α‐INDUCED APOPTOSIS VIA INDUCTION OF DEATH RECEPTORS IN MURINE FIBROBLASTS
Authors: Kimura Hirokazu , Minakami Hisanori , Dr Akira
Published: October 2002

Ultraviolet B (UVB) irradiation causes cell death by apoptosis in murine fibroblast cells. Tumor necrosis factor‐α (TNF‐α) is also a well known inducer of apoptosis, although the physiological significance of this activity is poorly understood. We investigated the effects of pretreatment with UVB (312nm) on TNF‐α‐induced apoptosis in murine fibroblast cells. UVB enhanced susceptibility to cell death by TNF‐α in a dose‐dependent manner. UVB but not TNF‐α induced the expression of TNF receptor type‐1 (TNFR‐1) and type‐2 (TNFR‐2) in a dose‐dependent manner. Expression of Fas (CD95) and Fas‐ligand (Fas‐L), and significant DNA fragmentation were observed in the cells that died. These results suggest that UVB irradiation modulates susceptibility to TNF‐α‐induced apoptosis through the induction of TNFRs, Fas, and Fas‐L in murine fibroblasts.
A COMPARED STUDY ON THE PURIFICATION OF FETAL AND ADULT RAT HEPATOCYTE SUSPENSIONS BY BIOMAGNETIC ISOLATION TECHNIQUES AND FLOW CYTOMETRY ANALYSIS
Authors: Arza E. , Cubero F. J. , García‐Barrutia M. S. , Ortiz A. , Maganto P. , Mula N. , Arahuetes R. M.
Published: October 2002

An analysis of liver cell populations from both adult and 21 day pregnancy rat fetuses (E21) was carried out. The results show that E21 hepatocytes express OX‐43, as do endothelial cells but not adult hepatocytes. OX‐43 could be used in future as a cell marker for the hepatocyte maturation.
MITOGENIC STIMULATION IN ISOPROTERENOL TREATED CELLS OF DICTYOSTELIUM DISCOIDEUM
Authors: Kumar Akhilesh , Chatterjee Samar
Published: October 2002

Amoebae of the cellular slime mould Dictyostelium discoideum showed stimulated mitogenic activity when exposed to 200μM isoproterenol, an activator of adenyl cyclase, for 30min. Approximately 40% increase in cell proliferation was found at 48h after isoproterenol treatment. A faster and larger plaque formation as well as higher uptake of FITC‐labelled E. coli indicates greater phagocytotic activity in the treated cells. A concurrent increase in DNA and protein syntheses was also recorded in the treated cells. Administration of 400μM caffeine or 200μM (+) propranolol brought down the isoproterenol‐induced elevation in the cell division rate to control levels. These results are discussed in relation to a precocious activation of adenyl cyclase in the treated cells leading to a transient but significant increase in cell division in this organism.
MITOTIC ACTIVITY OF THE DUODENAL CRYPT ENTEROCYTES IN MICE TRANSPLANTED WITH EA21A MAMMARY CARCINOMA
Authors: Barbeito Claudio G. , Albarenque Stella Maris , Reyna Juan C. , Flamini Mirta A. , Laube Pedro F. Andrés , Badrán Amado F.
Published: October 2002

The presence of a tumor generally changes the mitotic activity of the normal cell population in mice. In the present work, the mitotic activity of the duodenal crypt enterocytes in EA21a mammary carcinoma‐bearing mice was determined. The results show that there is a patent circadian variation in normal mice and, in the presence of the EA21a mammary tumor, cell proliferation is stimulated. Stimulation was evident in enterocytes from the intermediate as well as the superficial regions of the crypt. Some humoral factors produced by the transplanted tumor could interfere with the regulatory mechanism of the mitotic activity of duodenal crypt enterocytes.
INABILITY OF 50HZ MAGNETIC FIELDS TO REGULATE PKC‐ AND CA2+‐DEPENDENT GENE EXPRESSION IN JURKAT CELLS
Authors: Still Maria , Lindström Ewa , Ekstrand A. Jonas , Mild Kjell Hansson , Mattsson Mats‐Olof , Lundgren Erik
Published: October 2002

We have previously reported that the T cell line Jurkat registers the exposure of a sinusoidal extremely low frequency magnetic field at the level of the plasma membrane, resulting in activation of the tyrosine kinase p56lck, increase in inositol‐3‐phosphate levels and increase in intracellular calcium concentration within minutes. To elucidate if these events associated with changes in intracellular calcium ion levels were biologically significant, transient transfections of Jurkat cells were performed with calcium‐ion dependent reporter constructs. Three different enhancer/promoter constructs were studied coupled to the luciferase reporter gene. The luciferase activity of each construct was measured after treatment of transfected cells to EMF exposure alone, or in combination with ionomycin, phorbol ester or cross‐linking anti‐CD3 antibodies. There was no indication that the used EMFs could influence any of these reporter constructs.
STRUCTURE AND DYNAMICS OF THE FUSION PORE IN LIVE CELLS
Authors: Cho Sang‐Joon , Quinn Anthony S. , Stromer Marvin H. , Dash Sudhansu , Cho Jinah , Taatjes Douglas J. , Jena Bhanu P.
Published: October 2002

Atomic force microscopy reveal pit‐like structures typically containing three or four, ∼150nm in diameter depressions at the apical plasma membrane in live pancreatic acinar cells. Stimulation of secretion causes these depressions to dilate and return to their resting size following completion of the process. Exposure of acinar cells to cytochalasin B results in decreased depression size and a loss in stimulable secretion. It is hypothesized that depressions are the fusion pores, where membrane‐bound secretory vesicles dock and fuse to release vesicular contents. Zymogen granules, the membrane‐bound secretory vesicles in exocrine pancreas, contain the starch digesting enzyme, amylase. Using amylase‐specific immunogold labeling, localization of amylase at depressions following stimulation of secretion is demonstrated. This study confirms depressions to be the fusion pores in pancreatic acinar cells. High‐resolution images of the fusion pore in live pancreatic acinar cells reveal the structure in much greater detail than has previously been observed.
EVIDENCE THAT THE NOVOBIOCIN‐SENSITIVE ATP‐BINDING SITE OF THE HEAT SHOCK PROTEIN 90 (HSP90) IS NECESSARY FOR ITS AUTOPHOSPHORYLATION
Authors: Langer T. , Schlatter H. , Fasold H.
Published: October 2002

The 90kDa heat shock protein (Hsp90) is one of the most abundant protein and essential for all eukaryotic cells. Many proteins require the interaction with Hsp90 for proper function. Upon heat stress the expression level of Hsp90 is even enhanced. It is assumed, that under these conditions Hsp90 is required to protect other proteins from aggregation. One property of Hsp90 is its ability to undergo autophosphorylation. The N‐terminal domain of Hsp90 has been shown to contain an unusual ATP‐binding site. A well‐known inhibitor of Hsp90 function is geldanamycin binding to the N‐terminal ATP‐binding site with high affinity. Recently it was shown that Hsp90 possesses a second ATP‐binding site in the C‐terminal region, which can be competed with novobiocin. Autophosphorylation of Hsp90 was analysed by incubation with γ32P‐ATP. Addition of geldanamycin did not interfere with the capability for autophosphorylation, while novobiocin indeed did. These results suggest that the C‐terminal ATP‐binding site is required for autophosphorylation of Hsp90.
p56lck CONTROLS PHOSPHORYLATION OF FILAMIN (ABP‐280) AND REGULATES FOCAL ADHESION KINASE (pp125FAK)
Authors: Goldmann Wolfgang H.
Published: October 2002

Transformation of cells by src ‐like kinases leads to altered cell morphology associated with the disassembly of focal contacts and concomitant increase in tyrosine phosphorylation of pp125FAK. p56lck is a lymphocyte‐specific member of the src family of protein tyrosine kinases that associates with cell surface glycoproteins such as CD4 and CD8. It phosphorylates and activates pp125FAK and increases its autokinase activity, thus pretreatment of pp125FAK with protein kinase C (PKC) markedly attenuates its phosphorylation and activation, suggesting a potential regulatory pathway of pp125FAK activation in focal contacts. p56lck further phosphorylates and activates actin binding protein (ABP‐280; filamin) and controls its association with cell surface receptors such as β‐2 integrins, actin filament cross‐linking, and possibly lipid membrane insertion.
DIRECT EVIDENCE FOR A ROLE OF β‐CATENIN/LEF‐1 SIGNALING PATHWAY IN INDUCTION OF EMT
Authors: Kim Kwonseop , Lu Zifan , Hay Elizabeth D.
Published: October 2002

Epithelial‐mesenchymal transformation (EMT) is an important process in development that is characterized by loss of E‐cadherin, β‐catenin relocalization, and acquisition of elongated cell shape and ability to invade ECM. β‐catenin has been shown to activate LEF‐1 transcription during EMT induced in vitro by c‐Fos. Here, we ask whether or not LEF‐1 directly introduced into epithelial cells in an adenovirus construct can induce EMT. In normal epithelial cell lines, such as HCE and MDCK cells, that contain functional APC, nuclear β‐catenin induced by exogenous LEF‐1 is rapidly exported and EMT is not induced. Leptomycin‐B blocks β‐catenin nuclear export, but no EMT occurs due to toxicity. Addition of Wnt‐1 to normal epithelial cell lines stabilizes cytoplasmic β‐catenin that LEF‐1 then transports to nuclei, causing a small amount of EMT. Our experiments demonstrated, however, that overexpressed LEF‐1 upregulates nuclear β‐catenin and promotes dramatic EMT in DLD‐1 epithelial tumors that retain nuclear β‐catenin. This EMT is reversible if the LEF‐1 virus is removed. Thus, our results demonstrate that LEF‐1 can induce EMT directly when its transcription activity is activated by stable nuclear β‐catenin. Normal adult epithelial cells appear to use APC to keep β‐catenin out of the nucleus, thereby avoiding pathologies such as metastases due to LEF/β‐catenin‐induced EMT.
DIFFERENT H2 RECEPTOR ANTIHISTAMINES DISSIMILARLY RETARD THE GROWTH OF XENOGRAFTED HUMAN MELANOMA CELLS IN IMMUNODEFICIENT MICE
Authors: Szincsák Nora , Hegyesi Hargita , Hunyadi Janos , Falus Andras , Juhász Istvan
Published: October 2002

Melanoma cells and tissues contain considerable amounts of histamine and express histamine receptors, suggesting the existence of autocrine and paracrine regulation by histamine. Our previous in vitro results suggested that histamine elevates melanoma cell growth through the H2 receptor. In this work we show that in vivo tumour proliferation in immunodeficient mice xenotransplanted with a human melanoma cell line is diminished by cimetidine, an H2 receptor antagonist, if combined with a tamoxifen derivate acting on cytochrome p450 molecules (DPPE). Ranitidine, another H2 receptor antagonist, has a weaker inhibitory effect, the kinetics and mechanism of which is probably dissimilar to that of the cimetidine/DPPE mixture.
Late Holocene Sea-Level Change on Rota and Guam, Mariana Islands, and Its Constraint on Geophysical Predictions
Authors: Kayanne Hajime , Ishii Teruaki , Matsumoto Eiji , Yonekura Nobuyuki
Published: October 2002

Holocene emergent reefs and notches are well distributed on Rota and Guam. Relative sea-level changes at these islands are reconstructed based on geomorphological observations and borings on present and emergent reefs, together with 54 radiocarbon dates. Sea level rose gradually to a maximum of 1.8 m between 6000 and 4200 yr B.P. and reached its highest level by 4200 yr B.P. on both islands. After 3200 yr B.P. abrupt uplift caused emergence of the reef. By subtracting the tectonic effect, we obtained the sea-level change in the Marianas: sea level reached its present level by 4200 yr B.P. and has remained almost stable since then. Reconstructed late Holocene sea-level change in the Mariana Islands provides constraints on geophysical models of sea-level variations.
Variability of Monsoon Climate in East Asia at the End of the Last Glaciation
Authors: Weijian Zhou , Donahue Douglas J. , Porter Stephen C. , Jull Timothy A. , Xiaoqiang Li , Stuiver Minze , Zhisheng An , Matsumoto Eiji , Guangrong Dong
Published: October 2002

High-resolution paleomonsoon proxy records from peat and eolian sand–paleosol sequences at the desert–loess transition zone in China denote a rapid oscillation from cold–dry conditions (11,200–10,600 14C yr B.P.) to cool–humid conditions (10,600–10,200 14C yr B.P.), followed by a return to cold–dry climate (10,200–10,000 14C yr B.P.). Variations in precipitation proxies suggest that significant climatic variability occurred in monsoonal eastern Asia during the Younger Dryas interval. Late-glacial climate in the Chinese desert–loess belt that lies downwind from Europe was strongly influenced by cold air from high latitudes and from the North Atlantic via the westerlies. The inferred precipitation variations were likely caused by variations in the strength of the Siberian high, which influenced the pressure gradient between land and ocean and therefore influenced the position of the East Asian monsoon front.
Palynological Evidence of Climatic and Oceanographic Changes in the North Sea during the Last Deglaciation
Authors: Rochon André , de Vernal Anne , Sejrup Hans-Petter , Haflidason Haflidi
Published: October 2002

Palynological analyses performed on cores from the Norwegian Channel (Troll 8903) led to reconstruction of the late-glacial variations in sea-surface conditions using dinoflagellate cyst data and permitted direct correlation with the vegetation history of northwestern Europe derived from pollen assemblages. By ∼15,000 yr B.P., ice rapidly receded from the Norwegian shelf and relatively warm summer conditions prevailed in surface waters. A first late-glacial cooling marked by extensive seasonal sea–ice cover is dated at ca. 13,600–13,00014C yr B.P., which coincides with the Oldest Dryas interval. During the Bølling–Allerød interval, a rise in sea-surface temperature both in February (up to 3°C) and August (up to 15°C) led to the establishment of ice-free conditions in the northern North Sea, while pollen data reveal a densification of the vegetation cover. The beginning of the Younger Dryas interval is marked by an increase in nonarboreal pollen input indicative of the opening of the forest vegetation cover, concomitant with a cooling of surface waters during winter and development of sea–ice cover. However, sea-surface conditions remained relatively warm in summer until about 10,300 yr B.P., when extremely cold conditions and extensive sea–ice cover developed (up to 7 months/yr). Improving conditions are recorded in surface waters by ∼10,100 yr B.P., a few hundred years before the development of forest cover onshore, as shown by the pollen record. Such a discrepancy between marine and terrestrial indicators at the end of Younger Dryas time suggests a delayed response of the vegetation to regional climate warming.
Correlated Millennial-Scale Changes in Surface Hydrography and Terrigenous Sediment Yield Inferred from Last-Glacial Marine Deposits off Northeastern Brazil
Authors: Arz Helge W. , Pätzold Jürgen , Wefer Gerold
Published: October 2002

The stable isotope composition of planktonic foraminifera correlates with evidence for pulses of terrigenous sediment in a sediment core from the upper continental slope off northeastern Brazil. Stable oxygen isotope records of the planktonic foraminiferal species Globigerinoides sacculiferand Globigerinoides ruber(pink) reveal sub-Milankovitch changes in sea-surface hydrography during the last 85,000 yr. Warming of the surface water coincided with terrigenous sedimentation pulses that are inferred from high XRF intensities of Ti and Fe, and which suggest humid conditions in northeast Brazil. These tropical signals correlate with climatic oscillations recorded in Greenland ice cores (Dansgaard-Oeschger cycles) and in sediment cores from the North Atlantic (Heinrich events). Trade winds may have caused changes in the North Brazil Current that altered heat and salt flux into the North Atlantic, thus affecting the growth and decay of the large glacial ice sheets.
Variations in Sediment Yield from the Upper Doubs River Carbonate Watershed (Jura, France) since the Late-Glacial Period
Authors: Bichet Vincent , Campy Michel , Buoncristiani Jean-François , Digiovanni Christian , Meybeck Michel , Richard Hervé
Published: October 2002

The Upper Doubs River Valley is a 910-km2watershed feeding into Lake Chaillexon. The lake was formed by a natural rockfall at the end of the Bølling Chronozone (around 14,250 cal yr B.P.) and since then has trapped material eroded from the watershed. The filling process and variations in sediment yield have been investigated by mechanical coring, seismic surveys, and electric soundings. The detrital sediment yield of the upstream watershed can be calculated by quantifying the sedimentary stocks for each climatic stage of the Late-Glacial period and Holocene Epoch and estimating the lake's entrapment capacity. This enables us to determine the intensity of the erosion processes in relation to climate and environmental factors. The Bølling–Allerød Interstade produced the greatest yields with mean values of 19,500 metric tons per calendar year (t/yr). The Younger Dryas Chronozone saw a sharp fall (8900 t/yr) that continued into the Preboreal (2100 t/yr). Clastic supply increased during the Boreal (4500 t/yr) before declining again in the Early Atlantic (2400 t/yr). Since then, yields have risen from 4500 t/yr in the Late Atlantic to 6800 t/yr in the Subboreal and 11,100 t/yr in the Subatlantic. Comparison of quantitative data with the qualitative analysis of the deposits and with the paleohydrologic curve of the watershed based on level fluctuations in lakes around Chaillexon shows that climate was the controlling factor of sediment yield until the Late Atlantic. From the Late Atlantic–Subboreal around 5400 cal yr B.P. (470014C yr B.P.) and especially from the end of the Subboreal Chronozone and during the Subatlantic Chronozone (2770 cal yr B.P./270014C yr B.P.–present) climatic constraints have been compounded by human activity related to forest clearing and land use.
Organizational learning communities and the dark side of the learning organization
Authors: Owenby Phillip H.
Published: October 2002

This chapter explores some aspects of learning communities in organizations, with a special focus on manager‐employee power relationships and the challenges of establishing learning organizations in traditional hierarchical organizations.
Approximate channel identification viaδ‐signed correlation
Authors: Balakrishnan J. , Sethares W. A. , Johnson C. R.
Published: October 2002

A method of approximate channel identification is proposed that is based on a simplification of the correlation estimator. Despite the numerical simplification (no multiplications or additions are required, only comparisons and an accumulator), the performance of the proposed estimator is not significantly worse than that of the standard correlation estimator. A free (user selectable) parameter moves ‘smoothly’ from a situation with small sum‐squared channel estimation error but hard‐to‐identify channel peaks, to one with a larger sum‐squared estimation error but easy‐to‐identify channel peaks. The proposed estimator is shown to be biased and its behaviour is analysed in a number of situations. Applications of the proposed estimator to sparsity detection, symbol timing recovery and to the initialization of blind equalizers are suggested. Copyright © 2002 John Wiley & Sons, Ltd.
A modified second‐order SPSA optimization algorithm for finite samples
Authors: Zhu Xun , Spall James C.
Published: October 2002

We propose a modification to the simultaneous perturbation stochastic approximation (SPSA) methods based on the comparisons made between the first‐ and second‐order SPSA (1SPSA and 2SPSA) algorithms from the perspective of loss function Hessian. At finite iterations, the accuracy of the algorithm depends on the matrix conditioning of the loss function Hessian. The error of 2SPSA algorithm for a loss function with an ill‐conditioned Hessian is greater than the one with a well‐conditioned Hessian. On the other hand, the 1SPSA algorithm is less sensitive to the matrix conditioning of loss function Hessians. The modified 2SPSA (M2SPSA) eliminates the error amplification caused by the inversion of an ill‐conditioned Hessian. This leads to significant improvements in its algorithm efficiency in problems with an ill‐conditioned Hessian matrix. Asymptotically, the efficiency analysis shows that M2SPSA is also superior to 2SPSA in a large parameter domain. It is shown that the ratio of the mean square errors for M2SPSA to 2SPSA is always less than one except for a perfectly conditioned Hessian or for an asymptotically optimal setting of the gain sequence. Copyright © 2002 John Wiley & Sons, Ltd.
Growth by acquisition and the performance of large food retailers
Authors: Bjornson Bruce , Sykuta Michael E.
Published: October 2002

The latter 1990s witnessed rapid growth among the largest retail food chain companies, much of it through acquisitions. An explanatory motive is that grocery chains could achieve greater scale economies and operating efficiencies, and increase their bargaining power with packaged food manufacturer‐suppliers. This article begins to examine whether the largest retailers are realizing the promised financial rewards associated with this growth trend. We examine the performance of the three largest U.S. food retailers, Albertson's, Inc., The Kroger Company, and Safeway Inc., over 7 fiscal years beginning in calendar year 1993 and ending in fiscal year 1999, a period that covers the recent increase in acquisition activity. Overall, we find only modest evidence that the financial returns to the rapid growth strategies of the three largest food retailers have begun to be realized through fiscal year 1999. [EconLit citations: G390, G340, Q130] © 2002 Wiley Periodicals, Inc.
Successful treatment of anemia in idiopathic myelofibrosis with recombinant human erythropoietin
Authors: Hasselbalch Hans Carl , Clausen Nielsaage Tøffner , Jensen Bjarne Anker
Published: October 2002

Thirteen patients with idiopathic myelofibrosis (5 osteomyelosclerosis) were treated with recombinant human erythropoietin (rHuEpo) for transfusion‐dependent anemia. All but 7 patients were concomitantly treated with alpha interferon, and 5 patients also received a interferon before the start of erythropoietin (EPO) treatment. All but two patients became transfusion independent. The highly positive results of the present study of transfusion‐dependent patients with idiopathic myelofibrosis calls for further studies to delineate more precisely in larger series those patients who are likely to respond to rHuEpo. Am. J. Hematol. 70:92–99, 2002. © 2002 Wiley‐Liss, Inc.
Monoclonal gammopathy after low‐grade MALT lymphoma: Evidence for a second neoplasm
Authors: Pachmann S. , Anderegg B. , Müller‐Höcker J. , Nathrath W. , Brack N. , Tigges F.J. , Hartenstein R. , Munker R.
Published: October 2002

We report the case of a patient with lymphoma of the salivary gland, at first diagnosed as lymphoma of mucosa‐associated lymphoid tissue (MALT lymphoma) but later found to infiltrate the bone marrow. At diagnosis, the patient had a polyclonal increase of gamma‐globulins. Five years after initial diagnosis, the patient presented with monoclonal gammopathy and infiltration of the bone marrow with neoplastic cells. Initially, the patient had received chemotherapy with different protocols (including etoposide, cyclophosphamide, fludarabin, methotrexate, and vincristine), none of which induced a lasting response. Therapy with rituximab (chimeric anti‐CD20 monoclonal antibody) finally led to partial remission. Eighteen months after rituximab, progressive lymphoma in the abdomen and a monoclonal gammopathy developed. The bone marrow showed infiltration by lymphoplasmacytoid cells (monoclonal expression of the light‐chain type lambda, positive for CD20, heterogeneous expression of CD45). The patient achieved another short clinical response with 4 cycles of the CHOP‐protocol, but soon the lymphoma progressed again. Five years and 8 months after the initial diagnosis, the patient died from septicemia and progressive lymphoma. By polymerase chain reaction (PCR) for the IgH gene it was shown that lymphoma cells were initially oligoclonal in the salivary gland and, later, biclonal in the bone marrow. Sequencing of two bands of apparently same length showed that these manifestations of lymphoma were not identical. Taken together, our data show that the initial low‐grade oligoclonal MALT lymphoma was no longer present and a more aggressive biclonal lymphoma with plasmacytoid differentiation had developed. The new lymphoma was clonally distinct and produced high amounts of monoclonal IgG lambda by immunoelectrophoresis. The relationship of the second lymphoma to the initial MALT lymphoma is discussed. Am. J. Hematol. 70:167–173, 2002. © 2002 Wiley‐Liss, Inc.
Asymptomatic homozygous deletional β0‐thalassemia in an African individual
Authors: Faustino Paula , Reis Ana Batalha , Feliciano Helena , Ferrão Lénia , Pereira Patrícia , Picanço Isabel , Miranda Armandina , Seixas Teresa , Romão Luísa , Júnior Esmeraldina Correia , Lavinha João
Published: October 2002

Homozygosity or compound heterozygosity for β0‐thalassemia mutations most commonly results in a transfusion‐dependent thalassemia major phenotype. In this report, we describe a 55‐year‐old male, from Guinea‐Bissau, that had been asymptomatic and never transfused until being admitted to hospital with anemia, fever, splenomegaly, and asthenia. Following hospital admission, HIV‐2 and Mycobacterium tuberculosis infections were diagnosed, and biochemical and molecular studies revealed homozygosity for β0‐thalassemia. At the molecular level, this is the first description of homozygosity for the β0‐Black 1,393‐bp deletion. In this case, the complete absence of β‐globin gene expression seems to be compensated by an unusually high fetal globin gene expression (Hb F 96%). β‐Globin haplotyping results were compatible with the propositus being homozygous for the Black 2 haplotype and for the absence of the XmnI polymorphism at −158 of Gγ‐globin gene (−/−). Co‐inheritance of genetic factors usually associated with high Hb F levels was not detected. Otherwise, the propositus is a heterozygote for the α‐globin gene 3.7‐kb deletion that is a beneficial modulating factor but not sufficient to explain this extremely mild phenotype. This unusual genotype/phenotype association is discussed in terms of the mechanisms underlying hemoglobin switching during development. Am. J. Hematol. 70:232–236, 2002. © 2002 Wiley‐Liss, Inc.
Bcl‐2 family of proteins in indolent B‐cell non‐Hodgkin's lymphoma: Study of 116 cases
Authors: Agarwal Beamon , Naresh Kikkeri N.
Published: October 2002

The bcl‐2 family of proteins comprises both antagonists and agonists of apoptosis. We have investigated whether subsets of indolent B‐cell non‐Hodgkin's lymphoma (IB‐NHL) differ in the expression of the bcl‐2 family members; 116 cases of IB‐NHL, composed of chronic lymphocytic leukemia (CLL, n = 48), follicular lymphoma (FL, n = 38), marginal zone B‐cell lymphoma (MZBCL, n = 15), and mantle cell lymphoma (MCL, n = 15), were investigated for expression of bcl‐2, bcl‐X, mcl‐1, bax, and bak proteins by immunohistochemistry. Expression of bcl‐2 and bcl‐X proteins was moderate/high among most IB‐NHLs. Expression of mcl‐1 was low/absent in most cases of CLL and MCL and low/moderate in most cases of FL and MZBCL. Most MCLs did not express bax protein. Bax expression was absent/low among most cases of CLL and low/moderate among most cases of FL and MZBCL. Expression of bak was moderate/low among most cases of CLL, MZBCL, and MCL but was absent/low among most cases of FL. The different subsets of IB‐NHLs differ in their expression of mcl‐1, bax, and bak proteins. Am. J. Hematol. 70:278–282, 2002. © 2002 Wiley‐Liss, Inc.
Chylothorax in chronic lymphocytic leukemia patient
Authors: Doerr Clinton H. , Staats Bruce A. , Markovic Svetomir N.
Published: October 2002

Chronic lymphocytic leukemia (CLL) is rarely complicated by chylothorax: we present a 93‐year‐old woman with CLL who developed recurrent pleural effusions that were ultimately found to be chylous in nature. Despite eight repeated thoracenteses, she continued to experience re‐accumulation of fluid, and therefore, video‐assisted thoracotomy with mass ligation of the thoracic duct region plus pleurodesis was performed to resolve the chylothorax. Despite her age and underlying disease, she did well during follow‐up. The etiology and management of chylothorax are also reviewed. Am. J. Hematol. 70:237–240, 2002.© 2002 Wiley‐Liss, Inc.
Sickle erythrocyte adherence to endothelium at low shear: Role of shear stress in propagation of vaso‐occlusion
Authors: Montes Richard A.O. , Eckman James R. , Hsu Lewis L. , Wick Timothy M.
Published: October 2002

Under venular flow conditions, sickle cell adherence to endothelium is mediated by cell adhesion molecules and adhesive proteins associated with inflammation, coagulation, and endothelial perturbation. Periodic and reduced blood flow are observed in sickle microcirculation during hematologic steady state, suggesting that blood flow is compromised in sickle microcirculation. We tested the hypothesis that low blood flow enhances adherence by quantifying sickle cell adhesion to endothelium under venular flow (1.0 dyne/cm2 shear stress) and low flow (0.1 dyne/cm2 shear stress), with and without addition of adhesion promoting agonists. Under low flow, sickle cell adherence to endothelium increases with contact time in the absence of endothelial activation or adhesive protein addition. In contrast, at venular shear stress, sickle cell adherence only occurs following endothelial activation with TNF‐α or addition of thrombospondin. Analysis of these data with a mathematical model reveals that at low flow adherence is “transport‐controlled,” meaning that contact time between sickle cells and endothelium is a more important determinant of adherence than high‐affinity receptor–ligand interactions. Low‐affinity interactions are sufficient for adhesion at low flow. In contrast, at venular flow (1 dyne/cm2 shear stress) adherence is “affinity‐controlled,” meaning that adherence requires induction of specific high‐affinity receptor–ligand interactions. These findings demonstrate that in addition to activating factors and adherence proteins, microvascular shear stress is an important determinant of sickle cell adhesion to endothelium. This suggests that in vivo, erythrostasis is an important determinant of adhesion that can act either independently or concurrently with ongoing acute events to induce adhesive interactions and vaso‐occlusion. Am. J. Hematol. 70:216–227, 2002. © 2002 Wiley‐Liss, Inc.
Skeletal clues apparently distinguishing Waldenstrom's macroglobulinemia from multiple myeloma and leukemia
Authors: Rothschild B.M. , Ruhli F. , Rothschild C.
Published: October 2002

This study was conducted to characterize macroscopically and by conventional radiography the bony lesions in a case of Waldenstrom's macroglobulinemia and to compare and contrast it with those of the other major hematologic lymphoproliferative disorders, multiple myeloma and leukemia. Two varieties of lytic skeletal lesions were found in Waldenstrom's macroglobulinemia. One was sharply defined, spheroid lesions with smooth borders and effaced/erased trabeculae. The second was in the form of coalescing pits (holes) with smooth, minimally remodeled edges. The appearance combined features of multiple myeloma and leukemia, but were mutually exclusive in those diseases. Spheroid lesions with effaced edges were absent in leukemia, while pits were absent in multiple myeloma. Fronts of resorption were not noted in Waldenstrom's macroglobulinemia. The combination of some of the features of leukemia and myeloma appear to allow recognition of Waldenstrom's macroglobulinemia. Am. J. Hum. Biol. 14:532–537, 2002. © 2002 Wiley‐Liss, Inc.
Cancer genetics
Authors: Knudson Alfred G.
Published: October 2002

Cancer is a genetic disease of somatic cells. Tumor karyotypes are rarely normal, and most show multiple abnormalities of both number and structure. The first direct evidence for this concept of cancer came from studies of tumor‐specific translocations in leukemias and lymphomas, revealing the importance of oncogenes and the regulation of gene transcription in cancer. A second major source of information about human cancer genes is hereditary cancer. Genetic predisposition of the autosomal dominant type imposes a high relative risk for one or more kinds of cancer. In the past decade or so, more than 30 mutant genes for such hereditary cancers have been cloned. Penetrance depends upon additional, somatic, mutations. A few of the genes are oncogenes or DNA repair genes, but most are tumor suppressor genes. Some tumor suppressors regulate transcription, while others operate in signal transduction pathways that are involved in regulating processes of cell birth, differentiation, and death. The knowledge gained is stimulating new approaches to the treatment and prevention of cancer. © 2002 Wiley‐Liss, Inc.
Wolfram syndrome: Identification of a phenotypic and genotypic variant from Jordan
Authors: Ajlouni Kamel , Jarrah Nadim , El‐Khateeb Mohammed , El‐Zaheri Mohamed , El Shanti Hatem , Lidral Andrew
Published: October 2002

Wolfram syndrome is an autosomal recessive disorder with probable locus heterogeneity. Only insulin‐dependent diabetes mellitus and progressive optic‐nerve atrophy are necessary to make the diagnosis, but associated findings include diabetes insipidus, sensorineural hearing loss, ataxia, peripheral neuropathy, urinary‐tract atony, and psychiatric illnesses. We performed clinical and molecular studies on four consanguineous families with 16 affected individuals. We point out a new phenotypic variant with absent diabetes insipidus, presence of peptic ulcer disease and bleeding tendency secondary to a platelet aggregation defect. The same phenotypic variant turned out to be a genotypic variant with linkage to a second Wolfram syndrome locus (WFS2) on chromosome 4q22–24. © 2002 Wiley‐Liss, Inc.