bluuebunny/crossref_metadata_2025_split huggingface dataset:
Focal adhesion kinase is abundant in developing blood vessels and elevation of its phosphotyrosine content in vascular smooth muscle cells is a rapid response to angiotensin II
Authors: Polte Thomas R. , Hanks Steven K. , Naftilan Allen J. 
Published: May 2005

AbstractFocal adhesion kinase (FAK) is a structurally unique nonreceptor protein‐tyrosine kinase that localizes to focal adhesion plaques. Regulation of its activity has been implicated in diverse signaling pathways, including those mediated by extracellular matrix/integrin interactions, G‐protein coupled receptors for mitogenic neuropeptides, and certain oncogene products. To gain evidence for specific processes in which FAK may be involved in vivo, a study was initiated to determine its expression pattern during mouse development. FAK expression was detected in early embryos and appeared to be distributed throughout all cell types at about the time of neurulation. Subsequent to neural tube closure, expression became particularly abundant in the developing vasculature. This included expression in the medial layer of arteries populated by smooth muscle cells. In vitro studies using cultured rat aortic vascular smooth muscle cells demonstrate that FAK phosphotyrosine content is dramatically elevated in response to plating cells onto the adhesive glycoprotein, fibronectin. Also, enhanced tyrosine phosphorylation of FAK is observed in these cells upon stimulation with the vasoconstrictor angiotensin II. Thus, in vascular smooth muscle cells, like fibroblasts, FAK appears to play a role in signaling mechanisms induced by extracellular matrix components as well as G‐protein coupled receptor agonists. The combined results of this study suggest that signaling through FAK may play an important role in blood vessel morphogenesis and function. © 1994 Wiley‐Liss, Inc.
Nongranular proteolytic enzymes of rat IL‐2–activated natural killer cells. II. Purification and identification of rat A‐NKP 1 and A‐NKP 2 as constituents of the multicatalytic proteinase (proteasome) complex
Authors: Wasserman Ken , Kitson Richard P. , Gabauer Megan K. , Herberman Ronald B. , Watkins Simon C. , Goldfarb Ronald H. , Rivett A. Jennifer , Sweeney Sean T. 
Published: May 2005

AbstractWe have recently described nongranular, cytosolic, high‐molecular‐weight trypsin‐like (A‐NKP 1) and chymotrypsin‐like (A‐NKP 2) proteases of interleukin‐2–activated rat natural killer (A‐NK) cells. A functional correlation between the inactivation of A‐NKP 2 and the inhibition of rat A‐NK cell‐mediated cytotoxicity was found. Herein we describe the 6,000‐fold purification of A‐NKP 2 to apparent homogeneity following: isopycnic sucrose gradient fractionation of postnuclear supernatants, molecular sieve chromatography, and heparin‐Sepharose® chromatography. We also report the novel finding that A‐NKP 2 as well as A‐NKP 1, derived from either rat A‐NK cells or the rat NK leukemic cell line CRNK‐16, are constituents of the multicatalytic proteinase (MCP/proteasome) complexes of these cells. Characteristic biochemical, biophysical, and electron microscopic/ultrastructural similarity to the rat liver proteasome was observed. However, Western blot analysis using polyclonal antibodies to the rat liver proteasome clearly indicated differences in the rat hepatic proteasome and the CRNK‐16–derived proteasomal subunits. The identification, characterization, and purification of A‐NKP 1 and A‐NKP 2, described herein, now allow for further investigation of the potential role of these proteasome components in NK cell function. Moreover, the proteasome of NK and A‐NK cells can now be compared and contrasted to the granzymes of lytic granules with respect to their role in cell‐mediated cytotoxicity. © 1994 Wiley‐Liss, Inc.
Methylation status and chromatin structure of an early response gene (ornithine decarboxylase) in resting and stimulated NIH‐3T3 fibroblasts
Authors: Laitinen Jens , Hölttä Erkki 
Published: May 2005

AbstractThe early response gene ornithine decarboxylase (odc) is indispensable for normal and malignant cell growth. Although DNA methylation is generally associated with chromatin condensation and gene inactivation, the odc gene is heavily methylated at CCGG‐sequences in animal cell lines. In this work we analyzed the chromatin structure and the DNA methylation status at the CpG‐rich promoter sequences at the odc locus in mouse 3T3 fibroblasts. We show that the proximal promoter region of the odc locus is not hypermethylated, while the distal promoter sequences appear to have a few methylated CCGG‐sites and display methylation polymorphism. Furthermore, it was found that the 5′ promoter region of odc is constitutively more sensitive to micrococcal nuclease than the coding and 3′ regions of the odc gene. Stimulation of the cells with serum resulted in an appearance of a DNase I sensitive site at the promoter region. The chromatin structure of the mid‐coding and 3′ regions of the odc gene also underwent structural changes that were accompanied by the rapid accumulation of odc mRNA. Such changes were not detected in the chromatin structure of glyceraldehyde‐3‐phosphate dehydrogenase (gadph) gene, whose expression remains invariant upon serum stimulation. These data suggest that the chromatin structure may play an important role in the rapid transcriptional activation of odc and other immediate early genes during serum stimulation. © 1994 Wiley‐Liss, Inc.
Effect of phorbol 12‐myristate 13‐acetate on Ca2+‐ATPase activity in rat liver nuclei
Authors: Oishi Kimiko , Yamaguchi Masayoshi 
Published: May 2005

AbstractThe effect of phorbol 12‐myristate 13‐acetate (PMA) on Ca2+‐ATPase activity in rat liver nuclei was investigated. Ca2+‐ATPase activity was calculated by subtracting Mg2+‐ATPase activity from (Ca2+‐Mg2+)‐ATPase activity. The nuclear Ca2+‐ATPase activity was significantly increased by the presence of PMA (2–20 μM) in the enzyme reaction mixture; the maximum effect was seen at 10 μM. The PMA (10 μM)‐increased Ca2+‐ATPase activity was not blocked by the presence of staurosporine (2 μM) or dibucaine (2 and 10 μM), an inhibitor of protein kinase. Meanwhile, vanadate (20 and 100 μM) caused a significant reduction in the nuclear Ca2+‐ATPase activity increased by PMA (10 μM). The present finding suggests that PMA has an activating effect on liver nuclear Ca2+‐ATPase independent of protein kinase. © 1994 Wiley‐Liss, Inc.
Evidence for posttranscriptional regulation of transgenic protein kinase C–alpha in T cells
Authors: Iwamoto Takashi , Ohkusu Kozo , Nakashima Izumi , Watanabe Masato , Hidaka Hiroyoshi 
Published: May 2005

AbstractRecently, we succeeded in establishing a transgenic mouse line which expressed high levels of protein kinase C (PKC)–alpha in thymocytes at the mRNA level with disproportionately small increases at the protein level. The transgenic PKC‐alpha was nevertheless functionally active for inducing accelerated cell growth and IL‐2 production by stimulation with anti‐receptor (CD3) antibody or phorbol 12‐myristate 14‐acetate (PMA) in vitro. Study of the dynamics of transgenic PKC‐alpha in the cells in vitro showed that the amount of PKC‐alpha protein increased in the cells remarkably at ⩾ 5 h after stimulation, whereas the level of PKC‐alpha mRNA did not change significantly or changed slightly. This suggested that cell activation breaks the posttranscriptional regulation of the transgenic PKC‐alpha in resting cells. The increase in PKC‐alpha protein accompanied a prolonged membrane translocation of PKC‐alpha and enhanced cell proliferation. Such a transgenic effect was inhibited completely by a PKC inhibitor, H‐7, added during 0–6 h after the stimulation. These results show formally that the transgenic PKC‐alpha whose production was accelerated through cell activation plays a key role in the late (for ⩾ 5 h) signal delivery for disregulated cell growth. © 1994 Wiley‐Liss, Inc.
Cellular and clinical perspectives on skeletal insulin‐like growth factor I
Authors: Delany Anne M. , Pash James M. , Canalis Ernesto 
Published: May 2005

AbstractInsulin‐like growth factor (IGF) I, a polypeptide synthesized by skeletal cells, is presumed to act as an autocrine regulator of bone formation. IGF I stimulates bone replication of preosteoblastic cells and enhances the differentiated function of the osteoblast. The synthesis of skeletal IGF I is regulated by systemic hormones, most notably parathyroid hormone and glucocorticoids, as well as by locally produced factors, such as prostaglandins and other skeletal growth factors. Whereas hormones and growth factors regulate IGF I synthesis, the exact level of regulation has not been established and may involve both transcriptional and posttranscriptional mechanisms. The IGF I gene contains six exons, and both exon 1 and 2 contain transcription initiation sites. Extrahepatic tissues, including bone, express exon 1 transcripts, and regulation of the exon 1 promoter activity in osteoblasts is currently under study. It is apparent that the regulation of IGF I gene transcription as well as the regulation of mRNA stability is complex and tissue specific. It is possible that abnormalities in skeletal IGF I synthesis or activity play a role in the pathogenesis of bone disorders. In view of its important anabolic actions in bone, it is tempting to postulate the use of IGF I for the treatment of disorders characterized by decreased bone mass. An alternative could be the stimulation of the local production of IGF I in bone. © 1994 Wiley‐Liss, Inc.
Induction of the collagenase phorbol ester response element by staurosporine
Authors: Shoshan Maria C. , Linder Stig 
Published: May 2005

AbstractThe indol alkaloid staurosporine is a potent inhibitor of protein kinase C, but has also been shown to have certain effects paradoxically similar to those of protein kinase C–activating phorbol esters. We show here that collagenase mRNA expression is stimulated by 10 nM staurosporine in normal and ras‐oncogene–transformed rat fibroblasts. The kinetics of collagenase mRNA induction by staurosporine were slow compared to induction by phorbol ester. Staurosporine induction of the collagenase promoter appeared to be mediated via the TPA response element (TRE). Induction did not involve any increase in jun mRNA expression and did not require expression of c‐Jun. Prolonged treatment with phorbol ester to deplete protein kinase C did not inhibit stimulation of the collagenase promoter by staurosporine. Instead, involvement of cAMP‐dependent protein kinase (PKA) was indicated by inhibition of staurosporine induction by the PKA inhibitor H‐89. In addition, raised levels of cAMP were observed during the first hour of staurosporine treatment. Altogether, our data indicate that staurosporine induces a PKA‐dependent pathway leading to c‐Jun–independent activation of the collagenase TRE element. © 1994 Wiley‐Liss, Inc.
Metastatic models of human cancer xenografted in the nude mouse: The importance of orthotopic transplantation
Authors: Kubota Tetsuro 
Published: May 2005

AbstractMetastatic model of human tumor xenografts have been developed using orthotopic transplantation of histologically intact tissue (onplantation) of lung, stomach, colon, pancreatic, prostate and bladder carcinomas. These models represent the entire process of the metastasis, consisting of local tumor growth, vascular and lymphatic invasion at the local site, flow in the vessels and lymphatic, extravasation at the metastatic organs, and seeding and growth at relevant metastatic sites. Orthotopically transplanted human small‐cell lung carcinoma displayed a different chemosensitivity pattern compared with the subcutaneous transplanted model, suggesting different pharmacodynamics between the orthotopic lung and the ectopic subcutaneous sites. The intact‐tissue orthotopic‐onplantation model seems to be useful to study the mechanism of metastasis for discovery of antimetastatic agents and for the patient tumors and for this treatment design.
Exploring processes of organization of normal and neoplastic epithelial tissues in gradient culture
Authors: Leighton Joseph 
Published: May 2005

AbstractThe biology of animal cells is often studied in individual cells or in sheets of cells. The relevance of such studies to the intact animal is unclear, since the spatial conditions encountered by cells in animals is one of dense three‐dimensional masses of cells, with limits to migration, and with gradients both of diffusion of metabolites and morphologic maturation. These spatial requisites have gradually been met in culture. A brief account describes sponge matrix culture for three‐dimensional growth and unilaminar, bilaminar, and radial histophysiologic gradient cultures. Some of the common neoplastic abnormalities of surface epithelial issues are considered. Proposals for investigating the histokinetic mechanisms regulating some epithelial tissue processes are suggested. In the most recent development of gradient culture methods, a thin transparent collagen membrane is intrinsically strengthened by producing a waffle membrane pattern for histophysiologic gradient culture.
Rationale for using TNFα and chemotherapy in regional therapy of melanoma
Authors: Lejeune F. , Liénard D. , Eggermont A. , Koops H. Schraffordt , Rosenkaimer F. , Gérain J. , Klaase J. , Kroon B. , Vanderveken J. , Schmitz P. 
Published: May 2005

AbstractRecombinant tumor necrosis factor‐alpha (rTNFα) has potent antitumor activity in experimental studies on human tumor xenografts. However, in humans, the administration of rTNFα is hampered by severe systemic side‐effects. The maximum tolerated dose range from 350 to 500 mg/m2, which is at least 10‐fold less than the efficient dose in animals. Isolation perfusion of the limbs (ILP) allows the delivery of high dose rTNFα in a closed system with acceptable side‐effects. A protocol with a triple‐drug regimen was based on the reported synergism of rTNFα with chemotherapy, with interferon‐y, and with hydperthermia. In melanoma‐in‐transit metastases (stage IIIA or AB) we obtained a 91% complete response, compared with 52% after ILP with melphalan alone. Release of nanograms levels of TNFα in the systemic circulation was evident but control of this leakage and appropriate intensive care resulted in acceptable toxicity. Angiographic, immunohistological, and immunological studies suggest that the efficacy of this prtocol is due to a dual targeting: rTNFα activates and electively lyses the tumor endothelial cells while melphalan is mainly cytoxic to the tumor cells. ILP with rTNFα appears to be a useful model for studying the biochemotherapy of cancer in man.
A complex composed of at least two HeLa nuclear proteins protects preferentially one DNA strand of the simple (gt)n(ga)m containing region of intron 2 in HLA‐DRB‐genes
Authors: Mäueler Winfried , Frank Gabi , Muller Marc , Epplen Jörg T. 
Published: May 2005

AbstractElectrophoretic mobility shift assays reveal that HeLa neuclear proteins bind fast and with measurable affinity to target DNAs containing mixed simple repetitive (gt)n(ga)m stretches. Preincubation of the proteins at elevated temperature prevents the formation of the major DNA/protein complex in favour of several distinct assemblies. A similar pattern of retarded bands was observed employing higher salt concentrations in binding reaction. Thus conformational changes of different proteins appear to influence the complex rather than alternating DNA structures. Separation of the total nuclear extract into a water soluble and an insoluble protein fraction leads to a complete loss of target DNA bindinlg capability of the fractions. The binding capacity is restored by combining the two fractions suggesting that at least two protein components are necessary to form a complex with the target sequence. The proteins can be differentiated into head sensitive, water soluble and temporary stable, water insoluble, respectively. Furthermore, specifically binding polypeptides are not detectable by Southwestern analyses, probably because the essential components are separated during electrophoresis. DNase 1 footpoint analyses yield four different protein binding regions only on the (gt)n(ga)m harbouring strand. The footprints cover larger portions of the mixed simple repeat in addition to a portion 5′ of the (gt)n part. Hence at lealst two nuclear protein components of unknown biological function have to be present simultaneously to protect preferentially the (gt)n(ga)m‐containing strand intron 2 in HLA‐DRB genes
Purification and characterization of two collagenase inhibitors from mouse sarcoma 180 conditioned medium
Authors: Rosenthal Rosalind A. , Moses Marsha A. , Shintani Yasushi , Megyesi Joseph F. , Langer Robert , Folkman Judah 
Published: May 2005

AbstractWe have previously shown that mouse sarcoma 180 cells produce vascular endothelial growth factor [VGEF; Rosenthal et al., 1990, Growth Factors, 4: 53–59], endothelial mitogen that stimulates angiogeneis. Recent reports have implicated metallaproteinases and their inhibitors in the regulation of vascular morphogeneis, tumor invasion, and metastasis. We report here that mouse sarcoma 180 cells produce two collagenase inhibitors. These inhibitors were purified by heparin‐Sepharose affinity chromatography, gel filtration, and C4 reverse phase h.p.l.c. Analytical gel electrophoresis of the purified inhibitors (MS‐22 and MS‐31) revealed molecular masses of 22,000 and 32,000 Da under reducing conditions, and 20,000 and 30,000 Da under nonreducing conditions, respectively. The NH2‐terminal amino acid sequence of MS‐22 was identical to that of tissue inhibitor of metalloproiteinases type 2 (TIMP‐2) produced by human melanoma cells (Stetler‐Stevenson et al., 1989, J. Biol. Chem. 264: 17374–17378) over the first 30 amino acids. The NH2‐terminal amino acid sequence of MS‐31 was identical to that of murine TIMP‐1 [Gewert et al., 1989 EMBO J 6:651–657]. Statistical analysis of the amino acid composition data of these two mouse sarcoma 180‐derived collagenase inhibitors confirms the identificationof MS‐22 as TIMP‐2 and MS‐31 as TIMP‐1.
Aluminum‐Induced DNA synthesis in osteobalsts: Mediation by a G‐protein coupled cation sensing mechanism
Authors: Quarles L. Darryl , Hartle J. Edward , Middleton John P. , Zhang Jian , Arthur John M. , Raymond John R. 
Published: May 2005

AbstractAlumminium (Al3+) stimulates de novo bono formation in dogs and is a potent stimulate for DNA synthesis in non‐transformed osteoblast in vitro. The recent identification of a G‐protein couplked cation‐sensing recepector(BoPCaR), which is activated by polycalant agonists [e.g., gadolinium (Gd3+) > neomycin > calcium(CA3+)], suggests that a similer physiologically inportant cation sensing receptor may be presant in obsoblasts and pharmacologically activated by Al3+. To evalute that possibility, we assessed whether known as BoPCaR agonists on DNA synthesis in a dose‐dependent fashion, achiving 50% effective extracelluler concennetration (EC50) of 10 μM, 30 μM, 60 μM, and 2.5 mM, respectively. Al3+ displayed non‐additive effect on DNA sunthesis with the BoPCAaR agonists as well as an unrelated G‐porotien coupled receptor agonists, PGF2α, suggesting shared mechenisms of action. In contrast, the recepator tyrosine kinse agonist, IGF‐1(10 ηg/ml), displayed additive proliferative effects when comboined with AlCl3, inducating distinct signalling pathways. AlCl3 (25 μM) induced DAG levels 2‐fold and the phosphorylation of the myristoylated alanine‐rich C kinase (MARKS) substrates 4‐fold, but did not increase intracelluler calcium concenitrations. Doen‐regardation of PKC by pre‐treatment with phorbol 12‐myristate 13‐acetate as well as PKC inhebitation by H‐7 and staurosporine blocked Al3+ ‐inducing DNA synthesis. Finally, Al3+, Gd3+, nemomycin, and Ca2+ activated G‐proteins inn osteoblast membrans as evidenced by increased colvant binding pf [32P]‐GTP‐azidoanilide to putaitve Gα subunits. Our findings suggests that Al3+ stimulates DNA synthesis in ostoblasts through a cation sansing mechnism coupled to G‐protein activation and signalling cascades involvings DAG and PCK‐ dependent pathways.
Polymer substrates for controlled biological interactions
Authors: Cima Linda Griffith 
Published: May 2005

AbstractThe identification of a myriad of small peptide and carbohydrate lieands recognizes by cell surface receptors has generated enthusiasm for the use of these ligands of components of biomaterials dor controlling cellular interactions. Achiening control of cell interaations via ligand modification of materials also refquires that nonspecific interactions of cells with these materials due to supface adsorption of biological macromolecules is milimized. Polyetylene oxide (PEO) exhibits extraordinary inertness toward most biological macromlecules and is thus receiving increasing attention as a component of new materials for controlling cell behavior. Both surface and bulk modifications with PEO are being applied to develop a range of bland substrate material as vehicles for ligand immobilization.
Influence of polysaccharides on neutrophil function: Specific antagonists suggest a model for cooperative saccharide‐associated inhibition of immune complex‐triggered superoxide production
Authors: Zhang Kang , Petty Howard R. 
Published: May 2005

AbstractWe have previously shown that certain monoisaccharides (N‐acfetyl‐D‐glucosamine and mannose) could cooperativly inhabit the ability of neutrophils to release superoxide anions in response to immuule complexes. To test the possible orgins of the cooperative inhibition of superoxide releaqe,m we have examined the effect of a panel of particular β‐glucan and hyaluronan triggered superoxide pelease from neutrophils, other polysaccharides including chitin and mannan were without effeat. Both chitin and mannan, but not other polysaccharides, inhibited the immune complex‐mediated qtimulation of superoxide peleaqe in a dose‐dependent fashion, In sharp contrast to the coopepative inhibition mediated by monosaacharides, chiting and mannan exhitbted Hill coefficients of 1. This inhibition of superoxide production was not due to simple blockage of Fc receotirs since fluorescent immune complexes bound equlally well to neutrophils in the presence of mannan of chitin as shown by equfluorescence microscopy and quantitative fluorometpy. Furthermore, this inhibition of superoxide release was lot observed when neutrophils were qtimulated with phorbol myristate aaetate and ionophore A23187 or Hyaluronan. Therefope, the secific inhibition of superoxide production by mannan and hitin aould lot be explailed bu eithep peceptor blockage or by some nolspecific effects on cells. We suggest that there molicules interdere with a step in transmembrace qignalling, presumably involving the intergrin CR3. The obserted Hill Cofficients suggest the possibility that one polysaccharide may simultaniouslybind to two monosaccharide bindine sites yielding a Hill coefficient of 1, wheras individual monosacaharides seperately bind vielding a Hill coefficient of 2.