bluuebunny/crossref_metadata_2025_split huggingface dataset:
Telomerase activity is repressed during differentiation along the hepatocytic and biliary epithelial lineages: verification on immortal cell lines from the same origin
Authors: Fukutomi Marie , Enjoji Munechika , Iguchi Haruo , Yokota Masaki , Iwamoto Hiroaki , Nakamuta Makoto , Sakai Hironori , Nawata Hajime 
Published: September 2002

AbstractRecent investigations indicate that telomerase activity regulates the life span of cells by compensating for telomere shortening during DNA replication. In addition, as differentiation progresses, telomerase activity is reduced in several different cell lineages. These findings lend support to the theory that more immature cells have greater remaining proliferative capacity and longer life span. However, it has not been directly demonstrated that the differentiation along a hepatocytic or a bile ductal lineage is accompanied by reduction of telomerase activity. In this study, we present direct evidence that telomerase activity is reduced during hepatocytic and biliary epithelial differentiation by using our unique cell lines including a stem‐like cell line, ETK‐1. When hepatocytic differentiation was induced in ETK‐1 by 5‐azacytidine, telomerase activity decreased significantly. Similarly, when we compared the telomerase activity on SSP‐25 and RBE cell lines from the same origin but representing different maturation stages of cholangiocarcinoma, more mature cells were found to possess significantly lower activity. These results indicate that the generally accepted relationship between telomerase activity and differentiation stage also applies in the hepatocytic and biliary epithelial lineages. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of retinoids and thiazolidinediones on proliferation, insulin release, insulin mRNA, GLUT 2 transporter protein and mRNA of INS‐1 cells
Authors: Blumentrath J. , Neye H. , Verspohl E. J. 
Published: September 2002

AbstractBoth 9‐cis‐retinoic acid (9cRA) and all‐trans‐retinoic acid (ATRA) are active metabolites of vitamin A (retinol). There exists an interaction between retinoid receptors and peroxisome proliferator‐activated receptors (PPARγ). To define their functions in an insulin secreting system the effects of ATRA, 9cRA and the PPARγ agonist rosiglitazone on cell proliferation, insulin release and glucose transporter (GLUT) 2 of INS‐1 cells were tested. Retinoic acid receptor (RAR‐α and ‐γ) and retinoid X receptor (RXR‐α and ‐β) proteins are present (immunoblots). Both 9cRA and ATRA inhibit INS‐1 cell proliferation ([3H]‐thymidine assay) in a concentration dependent manner. Both 9cRA and ATRA increased insulin release, but only ATRA ralsed the GLUT 2 mRNA in a bell‐shaped concentration response curve after 48 h. The insulinotropic effect of one compound is not significantly superimposed by the other indicating that the same binding sites are used by 9cRA and ATRA. The acute and chronic effects of the PPARγ agonist rosiglitazone on insulin release were additionally determined since glitazones act as transcription factors together with RXR agonists. At high concentrations (100 μm) rosiglitazone inhibited glucose (8.3 mm) stimulated insulin secretion (acute experiment over 60 min). Insulin secretion, however, was increased during a 24 h treatment at a concentration of 10 μm and again inhibited at 100 μm. Changes in preproinsulin mRNA expression were not observed. Rosiglitazone (100 μm) increased GLUT 2 mRNA paralleled by an increase of GLUT 2 protein, but only after 24 h of treatment. This data indicate that RAR and RXR mediate insulin release. The changes in GLUT 2 have no direct impact on insulin release; the inhibition seen at high concentrations of either compound is possibly the result of the observed inhibition of cell proliferation. Effects of rosiglitazone on preproinsulin mRNA and GLUT 2 (mRNA and protein) do not play a role in modulating insulin secretion. With the presence of an RXR receptor agonist the effect of rosiglitazone on insulin release becomes stimulatory. Thus the effects of RAR‐, RXR agonists and rosiglitazone depend on their concentrations, the duration of their presence and are due to specific interactions. Copyright © 2001 John Wiley & Sons, Ltd.
Differential inhibitory effects of carbon tetrachloride on the hepatic plasma membrane, mitochondrial and endoplasmic reticular calcium transport systems: implications to hepatotoxicity
Authors: Hemmings Susan J. , Pulga Vivian B. , Tran Sam T. , Uwiera Richard R.E. 
Published: September 2002

AbstractMitochondrial, endoplasmic reticular and plasma membrane fractions were isolated by a new method from control male Fischer 344 rats and rats given CCl4 by gavage. After 1 h of CCl4 treatment, rats were in glucose and pancreatic hormone balance but plasma levels of T3 and T4 were decreased 29 and 22%, respectively. After 24 hours of CCl4 treatment, rats were: hypoglycaemic and insulin and glucagon levels were increased 33‐ and 35‐fold, respectively; total T4 levels were decreased 62%; while total T3 levels were normalized. In liver fractions from CCI4‐treated rats, 1 h after CCl4 administration: (i) calcium binding was decreased 65% in the mitochondrial fraction, 66% in the endoplasmic reticular fraction and 46% in the plasma membrane fraction; (ii) calcium uptake was decreased 59% in the mitochondrial fraction, 46% in the endoplasmic reticular fraction and 37% in the plasma membrane fraction. After 24 h of CCl4 administration: (i) calcium binding was decreased 57% in the mitochondrial fraction, 50% in the endoplasmic reticular fraction and 71% in the plasma membrane fraction; (ii). calcium uptake was decreased 55% in the mitochondrial fraction, 17% in the endoplasmic reticular fraction and 53% in the plasma membrane fraction. In vitro studies indicated the plasma membrane calcium transport system to be rapidly (within a minute) and strongly (>90%) inhibited by CCl4. We conclude that CCl4 produces a differential inhibitory effect on the hepatoctye calcium pumps that are implicated with hepatocellular damage. Copyright © 2001 John Wiley & Sons, Ltd.
Cervico‐vaginal dysplasia—papillomavirus‐induced and HIV‐1 infection: role of correlated markers for prognostic evaluation
Authors: Pugliese A. , Andronico L. , Gennero L. , Pagliano G. , Gallo G. , Torre D. 
Published: September 2002

AbstractSexually‐transmitted diseases (STD) can facilitate the progression of HIV‐1 infection. Among them, as we have previously demonstrated, cervico‐vaginal dysplasia—papillomavirus (HPV)‐induced, together with HSV‐2 co‐infection, seems to be correlated with a more evident immunodepression in HIV‐positive women, compared with other sexually transmitted diseases. Here we have analysed some of the main correlated markers of HIV‐1 infection progression: CD4 + T lymphocyte concentration, CD4 +/CD8 + T cells ratio, HIV‐1 RNA loads and haemoglobin (Hb) concentration in 30 HIV‐1 positive women co‐infected with HPV, and suffering from cervico‐vaginal dysplasia, in different stages. In particular, we noticed a positive correlation, evaluated by Spearman's test, between the degree of progression of dysplastic stages (CIN1→3) until invasive carcinoma (IC) and HIV‐1 RNA loads (Cs = +0.78; p < 0.001), and in contrast, a negative correlation between the same stages of progression and respectively CD4+ T cell concentration (Cs = −0.54; p = 0.01), ratio (Cs =− 0.63; p = 0.002) and Hb concentration (Cs = −0.85; p < 0.001). In conclusion, it is important to underline that low levels of Hb generally paralleled the degree of immunodepression. In fact CD4 + T cell levels and ratio positively correlated with Hb concentrations respectively, with Cs = +0.83; p < 0.001 and Cs = +0.90; p < 0.001. Finally, the most efficacious antiretroviral combined therapy (HAART = Highly Active Antiretroviral Therapy) can improve the above described laboratory parameters in HIV‐1/HPV co‐infected women and seems to prevent the progression of CIN1 to the following stages of the dysplastic disease. Copyright © 2002 John Wiley & Sons, Ltd.
Transcriptional activation of the human insulin receptor gene by 1,25‐dihydroxyvitamin D3
Authors: Maestro B. , Molero S. , Bajo S. , Dávila N. , Calle C. 
Published: September 2002

AbstractTreatment with 10−8 m 1,25‐dihydroxyvitamin D3 for 24 h causes transcriptional activation of the human insulin receptor gene in U‐937 human promonocytic cells. The activation seems to potentiate the response to insulin in terms of glucose oxidation. Wortmannin, a phosphatidylinositol 3‐kinase inhibitor, causes a greater inhibition of insulin‐stimulated glucose oxidation in 1,25‐dihydroxyvitamin D3‐treated cells than in untreated cells. This suggests a stimulation of phosphatidylinositol 3‐kinase activity by 1,25‐dihydroxyvitamin D3, which could mediate, at least in part, the potentiation of the insulin response. Copyright © 2002 John Wiley & Sons, Ltd.
Melatonin in the unicellular Tetrahymena pyriformis: effects of different lighting conditions
Authors: Köhidai L. , Vakkuri O. , Keresztesi M. , Leppäluoto J. , Csaba G. 
Published: September 2002

AbstractMelatonin content in the cellular fraction and medium of Tetrahymena pyriformis GL cultures was measured at different time points of light and dark exposures. Tetrahymena produced, stored and secreted immunoreactive melatonin, which in displacement and HPLC studies, behaved like synthetic melatonin. There was not a continuous secretion of melatonin produced by the cells. In contrast to this, storage of melatonin was observed, which was more expressed in dark conditions. Prolonged light exposure suppressed melatonin production and secretion alike, however it did not block it completely. Copyright © 2002 John Wiley & Sons, Ltd.
Transcatheter closure of patent foramen ovale in patients with paradoxical embolism: Intermediate‐term risk of recurrent neurological events
Authors: Du Zhong‐Dong , Cao Qi‐Ling , Joseph Annette , Koenig Peter , Heischmidt Mary , Waight David J. , Rhodes Jonathan , Brorson James , Hijazi Ziyad M. 
Published: September 2002

AbstractClosure of patent foramen ovale (PFO) has been proposed as an alternative to anticoagulation in patients with presumed paradoxical emboli. We report our preliminary intermediate results of patients who underwent transcatheter PFO closure for paradoxical embolism using DAS‐Angel Wings occluder or Amplatzer devices. Eighteen patients (8 male/10 female) underwent catheter closure of their PFOs at a median age of 42 years. The complete closure rate was 67% immediately after the procedure and 100% at a mean follow‐up interval of 2.2 ± 1.8 years. The mean fluoroscopy time and procedure time in the Amplatzer group were 8.5 ± 3.2 min and 65 ± 21 min, respectively, which were significantly shorter than those of DAS‐Angel Wings group (18.9 ± 4.7 min and 137 ± 28 min, respectively). There were no recurrent embolic neurological events following device placement in this subset of patients. No complications were encountered either during or after the closure procedure. In conclusion, transcatheter closure of PFO seems to be an effective alternative therapy in the prevention of presumed paradoxical emboli. Further study is needed to identify patients most likely to benefit from this intervention. Cathet Cardiovasc Intervent 2002;55:189–194. © 2002 Wiley‐Liss, Inc.
New stent design for autologous venous graft–covered stent preparation: First human application for sealing of a coronary aneurysm
Authors: Stefanadis Christodoulos , Toutouzas Konstantinos , Tsiamis Eleftherios , Toutouzas Pavlos 
Published: September 2002

AbstractIn this case report, we present the first clinical application of a new stent design for autologous venous graft–covered stent preparation. This stent consists of a main body, resembling the configuration of conventional stents, and two connecting arms at the edges of the stent for the stabilization of the venous graft on the external surface of the stent. This new stent design was applied in a patient with an aneurysm in a stented segment in the right coronary artery. The immediate and long‐term angiographic evaluation after the covered stent implantation showed complete sealing of the aneurysm without restenosis. Cathet Cardiovasc Intervent 2002;55:222–227. © 2002 Wiley‐Liss, Inc.
Expression profiling of all protein‐coding genes in wild‐type and three DNA repair‐deficient substrains of Escherichia coli K‐12
Authors: Salmelin Camilla , Vilpo Juhani 
Published: September 2002

AbstractGene chips or cDNA arrays of the entire set of Escherichia coli (E.
coli) K12 genes were used to measure the expression, at the mRNA level,
of all 4290 protein‐coding genes in wild‐type (WT) and three DNA repair‐deficient
derivative strains: (i) AB1157 (WT), (ii) LR39 (ada, ogt), (iii)
MV1932 (alkA1, tag‐1) and (iv) GM5555 (mutS). The aim
was to investigate whether disruption of a single gene would result in significant
deviation in the expression of other genes in these organisms. We describe
here a simple approach for a stringent statistical evaluation of cDNA array
data. This includes: (i) determination of intra‐ and interassay variation
coefficients for different expression levels, (ii) rejection of biased duplicates,
(iii) mathematical background determination, and (iv) comparison of expression
levels of identical copies of a gene. The results demonstrated a highly significant
correlation of gene expression when the mutants were individually compared
with the wild‐type. Altogether, 81 deviations of the expression of 59 genes
were noted, out of 12,870, when 3‐fold or greater up‐ or down‐regulation was
used as a criterion of differential expression. In the light of current knowledge
of E. coli biology, the differential expression did not follow any
logical pattern. In fact, the deviations may simply represent inter‐assay
variation. The results obtained here with a simple model organism are different
from those obtained with most mammalian knockouts: disruption of the function
of a single gene does not, under good growth conditions, necessarily result
in great changes in the expression of other genes. Copyright ©
2002 John Wiley & Sons, Ltd.
Website Review: Cancer and the web
Authors: Robert Albertella Mark 
Published: September 2002

AbstractThe applications of functional genomics, proteomics and informatics to cancer research have yielded a tremendous amount of information, which is growing all the time. Much of this information is available publicly on the Internet and ranges from general information about different cancers from a patient or clinical viewpoint, through to databases suitable for cancer researchers of all backgrounds, to very specific sites dedicated to individual genes or molecules. A simple search for ‘cancer’ from a typical Web browser search engine yields more than half a million hits; an even more specific search for ‘leukaemia’ (>40 000 hits) or ‘p53’ (>5700 hits) yields far too many hits to allow one to identify particular sites of interest. This review aims to provide a brief guide to some of the resources and databases that can be used as springboards to home in rapidly on information relevant to many fields of cancer research. As such, this article will not focus on a single website but hopes to illustrate some of the ways that postgenomic biology is revolutionizing cancer research. It will cover genomics and proteomics approaches that have been applied to studying global expression patterns in cancers, in addition to providing links ranging from general information about cancer to specific cancer gene mutation databases. Copyright © 2001 John Wiley & Sons, Ltd.
From genome to function: systematic analysis of the soil bacterium Bacillus subtilis
Authors: Harwood Colin R. , Crawshaw Samuel G. , Wipat Anil 
Published: September 2002

AbstractBacillus subtilis is a sporulating Gram‐positive bacterium that lives primarily in the soil and associated water sources. Whilst this bacterium has been studied extensively in the laboratory, relatively few studies have been undertaken to study its activity in natural environments. The publication of the B. subtilis genome sequence and subsequent systematic functional analysis programme have provided an opportunity to develop tools for analysing the role and expression of Bacillus genes in situ. In this paper we discuss analytical approaches that are being developed to relate genes to function in environments such as the rhizosphere. Copyright © 2001 John Wiley & Sons, Ltd.
Featured Organism: Reductive evolution in bacteria: Buchnera sp., Rickettsia prowazekii and Mycobacterium leprae
Authors: Wixon Jo 
Published: September 2002

AbstractObligate intracellular bacteria commonly have much reduced genome sizes compared to their nearest free‐living relatives. One reason for this is reductive evolution: the loss of genes rendered non‐essential due to the intracellular habitat. This can occur because of the presence of orthologous genes in the host, combined with the ability of the bacteria to import the protein or metabolite products of the host genes. In this article we take a look at three such bacteria whose genomes have been fully sequenced. Buchnera is an endosymbiont of the pea aphid, Acyrthosiphon pisum, the relationship between these two organisms being so essential that neither can reproduce in the absence of the other. Rickettsia prowazekii is the causative agent of louse‐borne typhus in humans and Mycobacterium leprae infection of humans leads to leprosy. Both of these human pathogens have fastidious growth requirements, which has made them very difficult to study. Copyright © 2001 John Wiley & Sons, Ltd.
Vascular smooth muscle cell phenotypic modulation in culture is associated with reorganisation of contractile and cytoskeletal proteins
Authors: Worth Nathalie F. , Rolfe Barbara E. , Song Jian , Campbell Gordon R. 
Published: September 2002

AbstractSmooth muscle cells (SMC) exhibit a functional plasticity, modulating from the mature phenotype in which the primary function is contraction, to a less differentiated state with increased capacities for motility, protein synthesis, and proliferation. The present study determined, using Western analysis, double‐label immunofluorescence and confocal microscopy, whether changes in phenotypic expression of rabbit aortic SMC in culture could be correlated with alterations in expression and distribution of structural proteins. “Contractile” state SMC (days 1 and 3 of primary culture) showed distinct sorting of proteins into subcellular domains, consistent with the theory that the SMC structural machinery is compartmentalised within the cell. Proteins specialised for contraction (α‐SM actin, SM‐MHC, and calponin) were highly expressed in these cells and concentrated in the upper central region of the cell. Vimentin was confined to the body of the cell, providing support for the contractile apparatus but not co‐localising with it. In line with its role in cell attachment and motility, β‐NM actin was localised to the cell periphery and basal cortex. The dense body protein α‐actinin was concentrated at the cell periphery, possibly stabilising both contractile and motile apparatus. Vinculin‐containing focal adhesions were well developed, indicating the cells' strong adhesion to substrate. In “synthetic” state SMC (passages 2–3 of culture), there was decreased expression of contractile and adhesion (vinculin) proteins with a concomitant increase in cytoskeletal proteins (β‐non‐muscle [NM] actin and vimentin). These quantitative changes in structural proteins were associated with dramatic changes in their distribution. The distinct compartmentalisation of structural proteins observed in “contractile” state SMC was no longer obvious, with proteins more evenly distributed throughout the cytoplasm to accommodate altered cell function. Thus, SMC phenotypic modulation involves not only quantitative changes in contractile and cytoskeletal proteins, but also reorganisation of these proteins. Since the cytoskeleton acts as a spatial regulator of intracellular signalling, reorganisation of the cytoskeleton may lead to realignment of signalling molecules, which, in turn, may mediate the changes in function associated with SMC phenotypic modulation. Cell Motil. Cytoskeleton 49:130–145, 2001. © 2001 Wiley‐Liss, Inc.
Recovery of flagellar dynein function in a Chlamydomonas actin/dynein‐deficient mutant upon introduction of muscle actin by electroporation
Authors: Hayashi Masahito , Hirono Masafumi , Kamiya Ritsu 
Published: September 2002

AbstractFlagellar and ciliary inner‐arm dyneins contain actin as a subunit; however, the function of this actin subunit remains unknown. As a first step toward experimental manipulation of actin in dynein, we developed a method for introducing exogenous actin into Chlamydomonas cells by electroporation. A non‐motile mutant, ida5oda1, lacking inner‐arm dyneins due to the absence of conventional actin, was electroporated in the presence of rabbit skeletal muscle actin. About 20% of the electroporated cells recovered motility under optimal conditions. In addition, by taking advantage of their phototactic behavior, the rescued cells could be concentrated. Motility was also recovered with fluorescently labeled actin; in this case, axonemes became fluorescent after electroporation, suggesting that actin was in fact incorporated as a dynein subunit. The feasibility of incorporating a substantial amount of macromolecules by electroporation will be useful not only for studying actin function, but also for a variety of studies using Chlamydomonas in which no efficient methods have been developed for expressing or introducing foreign proteins and other macromolecules. Cell Motil. Cytoskeleton 49:146–153, 2001. © 2001 Wiley‐Liss, Inc.
Elastic extension and jump of the flagellar nexin links: A theoretical mechanical cycle
Authors: Cibert C. 
Published: September 2002

AbstractThe functions of the nexin links of a flagellar axoneme have not been clearly demonstrated. Taking into account both the elastic (Hookean) characteristics and the possible jump of the nexin links, we calculated the sliding to bending conversion of a theoretical model in a tip‐ward direction step by step, according to the essential principles proposed by the geometric clutch hypothesis [Lindemann, 1994: J Theoret Biol 168:175–189]: the activity of the dynein arms depends on the transverse forces induced by the axonemal curvature. In our calculations, however, the transverse forces that are involved in the regulation of the activities of the dynein arms were due to the extension of the nexin links located upstream of a given abscissa. This allowed us to define a bent segment as the axonemal portion at whose proximal and distal ends the nexin links were relaxed, and as fully extended as possible, respectively. The model creates an apparent disorder in the orientation of the nexin links as already observed [Bozkurt and Wooley, 1993: Cell Motil Cytoskeleton 24:109–118; Wooley, 1997: J Cell Sci 110:85–94]. We propose that the nexin links are involved in a mechanical cycle, whose 3 stages are (1) rapid extension, (2) slow relaxation, and (3) stand‐by. The rapid extension is compatible with the mechanical interactions between the nexin links and the inner dynein arms with which they form the dynein regulatory complex. This was correlated with the oscillating properties of the nexin links along the axoneme that allow them to be one of the regulatory elements of the local ATPase activity of the dynein arms. Cell Motil. Cytoskeleton 49:161–175, 2001. © 2001 Wiley‐Liss, Inc.