bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cascade of autophosphorylation in the β‐subunit of the insulin receptor
Authors: White Morris F. , Kahn C. Ronald 
Published: December 2004

AbstractInsulin stimulated autophosphorylation of the β‐subunit of the insulin receptor purified from Fao hepatoma cells or purified from Chinese hamster ovary (CHO/HIRC) or Swiss 3T3 (3T3/HIRC) cells transfected with the wild‐type human insulin receptor cDNA. Autophosphorylation of the purified receptor occurred in at least two regions of the β‐subunit: the regulatory region containing Tyr‐1146, Tyr‐1150, and Tyr‐1151, and the C‐terminus containing Tyr‐1316 and Tyr‐1322. In the presence of antiphosphotyrosine antibody (α‐PY), autophosphorylation of the purified receptor was inhibited nearly 80% during insulin stimulation. Tryptic peptide mapping showed that α‐PY inhibited autophosphorylation of both tyrosyl residues in the C‐terminus and one tyrosyl residue in the regulatory region, either Tyr‐1150 or Tyr‐1151. Thus, a bis‐phosphorylated form of the regulatory region accumulated in the presence of α‐PY, which contained Tyr(P)‐1146 and either Tyr(P)‐1150 or 1151. In intact Fao, CHO/HIRC, and 3T3/HIRC cells, insulin stimulated tyrosyl phosphorylation of the β‐subunit of the insulin receptor. Tryptic peptide mapping indicated that the regulatory region of the β‐subunit was mainly (>80%) bis‐phosphorylated; however, all three tyrosyl residues of the regulatory region were phosphorylated in about 20% of the receptors. As the phosphotransferase was activated by tris‐phosphorylation but not bis‐phosphorylation of the regulatory region of the β‐subunit (White et al.: Journal of Biological Chemistry 263:2969–2980, 1988), the extent of autophosphorylation in the regulatory region may play an important regulatory role during signal transmission in the intact cell.
Sulfation of the tumor cell surface sialomucin of the 13762 rat mammary adenocarcinoma
Authors: Hull Steven R. , Carraway Kermit L. 
Published: December 2004

AbstractASGP‐1, the major cell surface sialomucin of the 13762 ascites rat mammary adenocarcinoma, is at least 0.5% of the total ascites cell protein and has sulfate on 20% of its O‐linked oligosaccharide chains. We have used this system to investigate the O‐glycosylation pathway in these cells and to determine the temporal relationship between sulfation and sialylation. The two major sulfated oligosaccharides (S‐1 and S‐2) were isolated as their oligosaccharitols by alkaline boro‐hydride elimination, anion exchange HPLC, and ion‐suppression HPLC. From structural analyses S‐1 is proposed to be a branched, sulfated trisaccharide −O4S‐GlcNAcβ1,6‐(Galβ1,3)‐GalNAc and S‐2 its sialylated derivative −O4S‐GlcNAcβ1,6‐(NeuAcα2,3‐Galβ1,3)‐GalNac. Pulse labeling with sulfate indicated that sulfation occurred primarily on a form of ASGP‐1 intermediate in size between immature and mature sialomucin. Pulse‐chase analyses showed that the intermediate could be chased into mature ASGP‐1. The concomitant conversion of S‐1 into S‐2 had a half‐time of less than 5 min. Monensin treatment of the tumor cells led to a 95% inhibition of sulfation with the accumulation of unsulfated trisaccharide GlcNAcβ1,6‐(Galβ1,3)‐GalNAc and sialylated derivative GlcNAcβ1,6‐(NeuAcα2,3‐Galβ1,3)‐GalNac. These data suggest that sulfation of ASGP‐1 is an intermediate synthetic step, which competes with β‐1,4‐galactosylation for the trisaccharide intermediate and thus occurs in the same compartment as β‐1,4‐galactosylation. Moreover, sulfation precedes sialylation, but the two are rapidly successive kinetic events in the oligosaccharide assembly of ASGP‐1.
Two‐dimensional protein profiles of cultured stromal and epithelial cells from hyperplastic human prostate
Authors: Sherwood Edward R. , Berg Lori A. , McEwan Robert N. , Pasciak Robert M. , Kozlowski James M. , Lee Chung 
Published: December 2004

AbstractStudies were undertaken to compare and contrast the two‐dimensional protein profiles of epithelial and stromal cells from hyperplastic human prostate to establish the protein composition of the two major cellular components of the prostate. Epithelial and stromal cells were isolated from human prostate obtained from patients undergoing open prostatectomy for benign prostatic hyperplasia (BPH). Proteins, isolated from the two cell populations and separated by two‐dimensional (2D) electrophoresis, were analyzed by silver staining, fluorography of [35S]‐methionine‐labeled proteins, and immunoprotein blotting. Isolated prostatic epithelial cells, but not stromal cells, contained cytokeratin polypeptides 5, 6, 7, 8, 13, 14, 15, 16, 17, 18, and 19. Although vimentin could not be identified in silver stained 2D gels and fluorographs of cultured prostatic epithelial cells, a low level of immunoreactivity was noted following immunoblot analysis of epithelial cell proteins by the use of an anti‐vimentin polyclonal. Vimentin was prominently expressed in cultured prostatic stromal cells and could be identified on silver stained 2D gels, fluorographs, and immunoblots of stroma‐derived proteins. In addition, stromal marker proteins SM1, SM2, and SM3 were identified in 2D gels of stromal cells to distinguish them from epithelial cells. These studies demonstrate (1) the two‐dimensional protein profile and cytokeratin polypeptide composition of cultured epithelial cells from hyperplastic human prostate and (2) the 2D protein profile of cultured prostatic stromal cells and identification of specific stromal marker proteins.
Cytovillin and other microvillar proteins of human choriocarcinoma cells
Authors: Pakkanen Raimo , Vaheri Antti 
Published: December 2004

AbstractMicrovilli were isolated from cultured human JEG‐3 choriocarcinoma cells using a gentle shearing method. The protein components of the isolated microvilli were examined by sodium dodecylsulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and immunoblotting. The major Mr 42,000 and Mr 100,000 polypeptide bands reacted with anti‐actin and anti‐α‐actinin antisera, respectively. Extraction of the isolated JEG‐3 microvilli with Triton X‐100 left an insoluble cytoskeletal residue containing mainly actin, α‐acinin, and polypeptides of Mr 200,000, 55,000 and 35,000. The Mr 35,000 polypeptide remained insoluble only at high concentrations of free Ca2+. Immunoblotting analysis of the JEG‐3 microvilli indicated that they were devoid of tropomyosin, although the total JEG‐3 protein lysates gave a strong positive reaction with anti‐tropomyosin, antiserum. The different subcellular localization of cytovillin and tropomyosin was also shown by indirect immunofluorescence microscopy. Cytovillin, an Mr 75,000 microvillus‐specific membrane protein of JEG‐3 cells, existed in an oligomeric form (dimer or trimer) as shown by gel filtration of Triton X‐100 solubilized microvillar proteins and by native polyacrylamide gel electrophoresis of purified cytovillin. Disulfide bridges were not involved in the aggregation, because the mobility of cytovillin was similar under reducing and nonreducing conditions in SDS‐PAGE. Cytovillin was shown to be closely related to ezrin, a minor component of chicken intestinal brush border microvilli.
Phenotypic effects of overexpression of PKCβ1 in rat liver epithelial cells
Authors: Hsieh Ling‐Ling , Hoshina Sadayori , Weinstein I. Bernard 
Published: December 2004

AbstractWe have used a previously described retroviral expression vector pMV7‐PKCβ1 to develop derivatives of two rat liver epithelial cell lines, K16 and K22, that stably express about tenfold‐higher PKC activity than control cells. Despite these high levels of PKC, these cells did not exhibit gross morphologic changes, anchorage‐independent growth, or tumorigenicity. K16PKC‐4 and K22PKC‐2, two lines with the highest PKC enzyme activity, were studied further in terms of several responses to the phorbol ester tumor promoter TPA. When treated with 100 ng/ml of TPA, the control K16MV7 and K22MV7 cells displayed a slight change in morphology, whereas the K16PKC‐4 and K22PKC‐2 cells displayed a marked change in morphology. Northern blot analyses demonstrated that TPA induced increased levels of fos, myc, phorbin, and ODC RNAs in control K16MV7 and K22MV7 cells, with maximum induction occurring at about 0.5, 1, 8, and 8 h, respectively. In K16PKC‐4 and K22PKC‐2 cells, TPA induction of phorbin and ODC RNAs was markedly enhanced, but this was not the case for myc and fos RNAs. In addition, the levels of myc RNA were constitutively higher in both K16PKC‐4 and K22PKC‐2 cells than in the control cells. Taken together, these results provide direct evidence that PKC plays a critical role in modulating the expression of myc, phorbin, and ODC RNAs. On the other hand, overexpression of PKCβ1 is not itself sufficient to cause cell transformation.
Drug‐induced alterations of tumor necrosis factor‐mediated cytotoxicity: Discrimination of early versus late stage action
Authors: Kull Frederick C. , Besterman Jeffery M. 
Published: December 2004

AbstractThe killing of L‐M cells by murine tumor necrosis factor (mTNF) was investigated by a combination of drug, antiserum neutralization, and kinetic studies. Kinetic studies with 125I‐mTNF showed that the bulk of association of ligand with L‐M cells peaked within 2 hr and the ligand was not degraded. Cell surface receptors were depleted (down regulated) by 6 hr when death commenced. The off‐rates of acid dissociabie (surface bound) and acid‐indissociable (internalized) compartments were found to be 9 min and 35 hr, respectively. Nevertheless, complete cell killing required the persistent presence of mTNF for up to 20 hr. This requirement was ablated by the concomitant addition of cycloheximide. Antiserum completely inhibited cytotoxicity when it was applied up to 4 hr after mTNF, but antiserum added I hr after mTNF was not neutralizing in the presence of cydohe.ximide. Thus, the inclusion of cycloheximide temporally dissociated early events (internalization and signal transduction) from lysis. Other drugs with and without cycloheximide were found to preferentially affect either early or later aspects of cell death. Phorbol myristate acetate and the ionophore A23187 were potent inhibitors of cytotoxicity and staurosporine was a potent enhancer. These agents were more effective when added 1 hr before mTNF and cycloheximide than when added 1 hr after and likely affected early events in the cytolytic program. In contrast, chloroquine and cAMP likely affect more terminal aspects of cytotoxicity. Dibutyrylcyclic AMP, cholera, and pertussis toxins enhanced cytotoxicity. They were equipotent when added either before or after mTNF regardless of the presence of cycloheximide. Likewise, chloroquine was an equipotent inhibitor when added either before or after mTNF regardless of the presence ofcycloheximide. Agents that primarily affect association events may be more likely to impinge on other TNF‐mediated activities than agents that primarily affect lysis.
Inhibition of epidermal growth factor receptor activity by retinoic acid in glioma cells
Authors: Steck Peter A. , Hadi Azra , Lotan Reuben , Yung W. K. Alfred 
Published: December 2004

AbstractThe growth inhibitory effects of exogenously added retinoic acid (RA) on various cultured human glioma cells was observed to be heterogenous, with an ID50 ranging from 10−7 M to no response. The protein tyrosine kinase activity of epidermal growth factor receptor (EGF‐receptor) appeared to parallel the cell's growth responsiveness to RA. Cells sensitive to RA‐induced growth inhibition exhibited a dose‐dependent decrease in EGF‐receptor activity, whereas RA‐resistant cells showed no alterations in EGF‐receptor protein tyrosine kinase activity or expression. The modulation of EGF‐receptor by RA was further examined with RA‐sensitive (LG) and ‐resistant (NG‐1 ) cell lines. Both cell lines were approximately equal in their ability to bind and internalize epidermal growth factor in the presence or absence of RA. Several independent assays suggested that the inhibition of EGF‐receptor activity was independent of protein kinase C modulation as mediated by phorbol myristate acetate. However, alterations in associated glycoconjugates of EGF‐receptor were observed among the sensitive cells but not the resistant cells. These results suggest RA‐induced growth inhibition in sensitive cells may arise, at least in part, through alterations in EGF‐receptor activity and structure.
Analysis of gene expression during adipogenesis in 3T3‐F442A preadipocytes: Insulin and dexamethasone control
Authors: Moustaid Naïma , Lasnier Françoise , Hainque Bernard , Quignard‐Boulange Annie , Pairault Jacques 
Published: December 2004

AbstractIn the present study, we have investigated dexamethasone and insulin regulation of the expression of adipose‐specific mRNA, namely, glycerophosphate dehydrogenase (G3PDH) and adipsin, at different stages of differentiation. During adipose conversion, insulin promotes an accumulation of G3PDH mRNA which is linked to cell differentiation; in fully differentiated cells, insulin is not required to maintain G3PDH gene expression. Differentiating cells in serum deprived medium already exhibit, at day I, a maximal amount of mRNA encoding for adipsin, which is tenfold decreased by 10 nM of insulin; insulin also exerts a negative effect on the abundance of adipsin mRNA in mature cells. This result indicates that adipsin appears to be a very early marker of adipose conversion, the gene expression of which is down‐regulated by the presence of insulin. Dexamethasone (DEX) decreases the G3PDH message at all stages of adipose conversion, while it promotes the accumulation of adipsin mRNA mainly in differentiating cells. In DEX‐treated adipocytes, the transcription efficiency of the G3PDH gene is not altered, and reduction to 50% of the message is due essentially to an approximately twofold decrease in its half‐life.
Characterization of the hamster DDT‐1 cell aFGF/HGBF‐I gene and cDNA and its modulation by steroids
Authors: Hall Jeffrey A. , Harris Marie A. , Malark Marlene , Mansson Per‐Erik , Zhou Hua , Harris Stephen E. 
Published: December 2004

AbstractSyrian hamster DDT‐1 cells are derived from smooth muscle of the ductus deferens. DDT‐1 cell growth is increased by the addition of testosterone (T). Acidic fibroblast growth factor (aFGF) or basic fibroblast growth factor (bFGF) also known as heparin binding growth factor I and II (HBGF‐I and HBGF‐II) can replace T in the stimulation of growth in these cells. This phenomenon is correlated with testosterone's ability to elevate aFGF/HBGF‐I mRNA. The increase steady‐state levels of aFGF/HBGF‐I mRNA were documented by northern blots and by in situ hybridization. Using a 520 bp human aFGF/HBGF‐I cDNA probe, a genomic clone with a 38 kb DNA insert was isolated from a cosmid library. By restriction enzyme analysis and southern hybridization, it was determined that there are three coding exons. DNA sequence analysis showed all of the coding region and 3′ noncoding sequences were on this clone. A 5′ noncoding exon not in the 38 kb insert is indicated, based on the cDNA sequences and genomic sequences of aFGF/HBGF‐I's from hamster DDT‐1 cells and several other species. The cDNA for hamster aFGF/HBGF‐I was isolated from a DDT‐1 lambda gt11 library and sequenced. Comparison of the coding region of aFGF/HBGF‐I from four species shows a >90% conservation of amino acid sequence.
Developmental changes in levels of growth hormone mRNA in zucker rats
Authors: Ahmad Iqbal , Steggles Alan W. , Carrillo Alberto J. , Finkelstein Judith A. 
Published: December 2004

AbstractLevels of pituitary growth hormone (GH) messenger RNA (mRNA) were compared in groups of genetically obese (fa/fa) and lean (Fa/‐) littermate male Zucker rats at four different ages, 3, 5, 9, and 11 weeks, in order to determine the earliest age at which a difference between the two groups could be detected. No difference was seen in three‐week‐old animals. Five weeks of age was the earliest time at which the level of GH mRNA was significantly decreased in the obese rats; this decrease was present at all subsequent ages. Mean serum growth hormone levels were lower in obese animals at all ages, but the differences were not statistically significant because of the large individual variation associated with the pulsatile nature of GH release. The earliest occurrence of differences in GH mRNA level is later than some of the obesity associated abnormalities present in adipose tissue. The earliest time of the GH mRNA differences can be associated with the time when decreased protein deposition is initially seen in the obese rats. Because of this association, decreased GH mRNA may enhance the development of obesity.
Evans‐Elemente. Eine Entgegnung zu Masings Bemerkungen zur Theorie der Korrosion durch Lokalelemente
Authors: Wickert K. , Wiehr H. 
Published: December 2004

AbstractZusammenfassend läßt sich sagen, daß die Deutung der Evanschen Versuche erst dann mit unseren Ergebnissen übereinstimmt, wenn die Aktivitätshöhe der Elektrodenoberflächen berücksichtigt werden. Alle Formulierungen berücksichtigt werden. Alle Formulierungen allgemeinen Inhalts über die Evans‐Elemente führen zu Widersprüchen, wenn die Oberflächenaktivität nicht berücksichtigt wird. Da die Korrosion als ein Geschehen im atomaren Bereich aufzufassen ist, müssen auch die theoretischen Grundlagen der Korrosion aus diesem Gebiet entnommen werden. Das hat leider in einigen Fällen zu neuen Wortprägungen geführt, die aber unseres Erachtens hingenommen werden müssen.
Die Isolierung von Magnetblechen durch eine Glimmer‐Phosphatschicht
Authors: Wüstefeld A. 
Published: December 2004

AbstractEntwicklung der Verfahren zur Isolierung von Magnetblechen (Isolierung durch Papier oder Lack) — Grundlagen, Vorteile und Durchführung des Micacid‐Isolierverfahrens — Eigenschaften micacidisolierter Magnetbleche.
Werkstoffe und Böden
Authors: Haase L. W. 
Published: December 2004

AbstractAllgemeines chemisches Verhalten sowie spezielles Verhalten der Eisenmetalle (Reinsteisen, Flußstahl, Gußeisen), Nichteisenmetalle (Kupfer, Zink, Blei und deren Legierungen) und nichtmetallischen Baustoffe (Zement, Asbestzement, Beton, Ton, Steinzeug und Holz) in Erdböden.
Das Korrosionsverhalten von ferritischem und perlitischem Gußeisen mit Kugelgraphit. Eine kritische Betrachtung
Authors: Franke E. 
Published: December 2004

AbstractGefügeaufbau von „verformbarem Gußeisen”︁ — Korrosionsversuche mit Ni‐Mg‐ bzw. Mg‐behandeltem Gußeisen mit Kugelgraphit und mit handelsüblichem Gußeisen — Auswertung und Deutung der Versuchsergebnisse (Einfluß von Graphitmenge und ‐verteilungsform auf den Angriff in sauren, neutralen und alkalischen Mitteln) — Bodenkorrosion von „verformbarem Gußeisen”︁.
Experimentell bestimmte pH‐Werte in verdünnten NH3, CO2‐ und NaOH‐Lösungen. (Zum Gebrauch in Hochdruckkraftwerken)
Authors: Wickert K. , Wiehr H. , Jahr H.‐G. 
Published: December 2004

AbstractpH‐Wert von Betriebswässern und Korrosion der Metalle — Versuchsaufgabe, ‐einrichtungen und ‐durchführung — NH3‐bzw. CO2‐bzw. NaOH‐Gehalt und pH‐Wert von Wässern — Grobe pH‐Schätzungen — Temperaturkoeffizient des pH‐Wertes — Ermittlung des Salzgehaltes ammoniakhaltiger Kondensate aus elektrischer Leitfähigkeit und pH‐Wert — Zusammenfassung.
Graphitfarben
Authors: Hadert H. 
Published: December 2004

AbstractGraphitfarbenBei der allgemeinen Bleiknappheit finden heute Rostschutzfarben aus Graphit wieder größere Beachtung. Es werden deshalb die Eigenschaften geeigneter Graphitsorten sowie deren Anwendung als Rostschutzfarbe allein oder in Verbindung mit Bleifarben geschildert.
Klebstoff und Werkstoff
Authors: Peters R. 
Published: December 2004

AbstractUnter dem Gesichtswinkel der praktischen Anwendung von Klebstoffen in Industrie und Handwerk werden die beim Zustandekommen einer Klebeverbindung wirksamen wesentlichsten physikalischen und chemischen Kräfte diskutiert. Hierbei ergibt sich, daß sowohl bei der nassen als auch bei der trockenen Haftung ein bestimmtes Größenverhältnis zwischen den Adhäsions‐ und Cohäsionskräften zur Erzielung der maximalen Wirkung Vorbedingung ist. Die auftretenden Adhäsionskräfte sind bei ein und demselben Klebstoff von der Oberflächenbeschaffenheit des zu verbindenden Werktoffes abhängig, während die Cohäsionskräfte mit der Art des Klebstoffes selbst wechseln. Weiter werden einige in speziellen Fällen auftretende untergeordnete Kräfte beschrieben, die diese Vorgänge unterstützen oder hemmen.Nach der Aufzählung und kurzen Definition der für die Praxis wichtigen Klebstofftypen mit ihren hauptsächlichsten Anwendungsgebieten wird untersucht, welche Gesichtspunkte für die betriebliche Verarbeitungstechnik entscheidend sind. Verschiedene Werkstoffe können einerseits durch denselben Klebstoff verbunden werden, andererseits kann der gleiche Grundtyp in mehreren Formen vorliegen, von denen jede einzelne nur für eine bestimmte Verarbeitungsart geeignet ist.
Probleme der Abnahme und Betriebsüberwachung chemischer Apparate hinsichtlich der Werkstoffseite
Authors: Richard Kurt 
Published: December 2004

AbstractDas Bestreben, die Haltbarkeit und Betriebssicherheit der Fabrikationseinrichtungen in der chemischen Industrie zu steigern, setzt die Lösung einer Reihe von Problemen werkstofflicher Natur voraus, wofür einige kennzeichnende Beispiele angeführt werden.Bei gußeisernen, emaillierten Druckgefäßen können die Dehngrenzen des Gußeisens durch mehrfache Glühbehandlung so weit absinken, daß die Betriebsbeanspruchung eine erhöhte Verformung des Gefäßes bewirkt und hierbei zu einer Überschreitung der zeitabhängigen Festigkeitsgrenze und zum Rissigwerden des Emailüberzuges führt. Der Festigkeitsabfall des Gußeisens muß daher bei der Bemessung der Gefäße berücksichtigt werden.Für säurefeste Chrom‐Nickel‐Stähle wird eine Schnellprüfmethode besprochen, die eine Einzelstückprüfung ermöglicht, womit die Auffindung von Werkstoffverwechselungen wesentlich erleichtert wird. Zugleich wird die Frage der langwierigen Prüfung der Kornzerfallbeständigkeit erörtert, die dringend einer Vereinheitlichung bedarf.Bei der Betriebsüberwachung sind gefahrenursachen zu beachten, die bei chemischer, chemisch‐mechanischer und thermisch‐mechanischer Beanspruchung auftreten, wobei vor allem solche Schäden zu suchen sind, die zunächst verborgen bleiben.Als Beispiele werden die bei warmfesten Stählen nach langen Betriebszeiten beobachteten Erscheinungen wic Kerbempfindlichkeit, Absinken der Festigkeits‐ und Dehngrenzen, Schädigung, Versprödung, Graphitausscheidung und Erweichung besprochen und Folgerungen fü die Betriebsüberwachung gezogen.
Einfluß der Oberflächenbeschaffenheit auf die Biegewechselfestigkeit
Authors: Gimmel Paul 
Published: December 2004

AbstractVersuchsergebnisse von Umlaufbiegeversuchen aus dem Schrifttum sind, wie bekannt, nur begrenzt vergleichbar. Einer der Gründe für diese nachteilige Einschränkung bei der Auswertung liegt in Verschiedenartigkeiten bei der Bearbeitung der Staboberfläche. Die bekannte Darstellung über den Einfluß der Oberflächenbeschaffenheit und Bearbeitung auf die Dauerfestigkeit gibt für polierte Staboberflächen den höchsten Wert an.Bei neuerdings durchgeführten Umlaufbiegevrsuchen mit unlegierten Werkstoffen und hochfein polierten Proben war im Gegensatz dazu die Wechselbiegefestigkeit 5–18% niedriger als bei üblich geschliffenen oder polierten Stäben. Die sorgfältige Bearbeitung der Staboberfläche erfolgte hier durch Polieren wie bei der Herstellung eines „metallographischen Schliffes”︁. Etwa eine Stunde Polierzeit ergab eine spiegelblanke Staboberfläche, frei von Kratzern und Riefen. Die Mikrohärte der Staboberfläche ist dadurch z. B. bei Armco‐Eisen von 200 auf 130 kg/mm2 erniedrigt worden.Der Zustand der Bearbeitung von Umlaufbiegeproben sollte zur Verbesserung der Vergleichbarkeit von Ergebnissen der Wechselbiegefestigkeit von verschiedenen Prüfstellen gekennzeichnet sein.