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  • Analytical Chemistry and Spectroscopy  (6)
  • glycosylation  (5)
  • 1
    Digitale Medien
    Digitale Medien
    Markers of prognosis in breast cancer - the relationship between binding of the lectin HPA and histological grade, SPF, and ploidy (1993)
    Springer
    Breast cancer research and treatment 25 (1993), S. 247-256 
    Details
    ISSN: 1573-7217
    Schlagwort(e): breast cancer ; glycosylation ; HPA ; Helix pomatia lectin ; prognosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Abnormal cellular glycosylation as demonstrated by the binding of a lectin fromHelix pomatia (HPA) to paraffin-embedded sections has been shown in several studies to be associated with aggressive biological behaviour and poor long-term patient prognosis in breast cancer. This study aims to address the possibility that expression of the HPA binding ligand may be of prognostic significance through an association with increased cellular proliferation (as measured by S-phase fraction and histological grade), anaplasia (reflected in histological grade), or ploidy (DNA index). In a 24 year retrospective study, paraffin-embedded sections of 366 primary breast cancers were stained for binding of HPA. All tumours were assessed for histological grade. Flow cytometry was performed on all cases for which sufficient tumour tissue was available (358/366 cases) and S-phase fraction (SPF) and ploidy calculated. Data regarding patient age at diagnosis, nodal status, and tumour size were also recorded. Life table analyses revealed survival advantage for HPA ‘non stainers’ in comparison to ‘stainers’ (p〈 0.001); for patients with tumours of low grade vs. high grade (p〈0.001); and for those with tumours of low SPF vs. high SPF (p〈0.001). No survival advantage was shown for those with diploid vs. aneuploid tumours (p= 0.17). No association was apparent between HPA binding and grade, SPF, or ploidy (Chi squared values not significant). This was confirmed by multivariate analysis in which nodal status, tumour size, and SPF were independently predictive of survival. There was no confounding effect of grade, SPF, or ploidy upon the correlation between survival and HPA binding. HPA was, however, not independently predictive owing to its strong association with nodal status. The results of this study suggest that the prognostic significance of altered glycosylation, as detected by HPA binding, is unlikely to be through an association with proliferative rate, degree of anaplasia, or cellular ploidy, but may rather be through a direct association with the presence of nodal metastases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00689839
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  • 2
    Digitale Medien
    Digitale Medien
    Glycosylation patterns of the human colon cancer cell line HT-29 detected byHelix pomatia agglutinin and other lectins in culture, in primary tumours and in metastases in SCID mice (1994)
    Springer
    Clinical & experimental metastasis 12 (1994), S. 398-404 
    Details
    ISSN: 1573-7276
    Schlagwort(e): colon cancer ; glycosylation ; Helix pomatia agglutinin ; metastasis ; SCID mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Human colonic cancer cells (HT-29, 10 7 cells/dose) were injected subcutaneously between the scapulae of 19 severe combined immunodeficient (SCID) mice. After 19 days, large tumours had developed in 18 out of the 19 animals and the mice were then killed. Metastases were detected in the lungs of 16 animals but not in other organs investigated. Surgical removal of the primary tumour in another group of five animals led to a prolonged survival and further growth of metastases in the lungs. HT-29 injection into the tail vein (n=5)resulted in colonization of the lungs. The tumours that developed in the animals were signet cell carcinomas; these forms are not seen in HT-29 cells in culture. Glycoconjugate expression of the tumours was assessed using several lectins. In many cases the results indicated a stability of lectin-binding patterns from cell culture conditions to implantation into the SCID mice. This was true for the lectin Helix pomatia agglutinin (HPA), the binding of which is associated with a high metastatic potential in some human tumours, including colon cancer. All the primary tumours and metastases were HPA positive. This xenograft tumour model seems to be a clinically relevant system for the study of glycoconjugate expression in human colon cancer cells and their metastases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01755883
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  • 3
    Digitale Medien
    Digitale Medien
    The effect of mislabeled samples on the performance of the linear learning machine (1990)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990), S. 47-50 
    Details
    ISSN: 0886-9383
    Schlagwort(e): Classification ; Pattern recognition ; Preprocessing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Over the past 15 years the linear learning machine has been applied to a large number of chemical problems. The learning machine approach is conceptually simple and does not require knowledge about the statistical distribution of the data. However, there are problems associated with this approach. One problem which has not been investigated is the influence of mislabeled samples on the positioning of the hyperplane in feature space. If a few samples in a data set are incorrectly tagged prior to training (i.e. the samples are labeled as members of class 2 even though they are actually members of class 1), it is still possible using the linear learning machine to achieve a classification success rate of 100% for the training set. However, unfavorable results will be obtained for the prediction set. The magnitude of this effect and its potential implications regarding the proper use of the linear learning machine are discussed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cem.1180040106
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  • 4
    Digitale Medien
    Digitale Medien
    The effect of the dilution rate on CHO cell physiology and recombinant interferon-γ production in glucose-limited chemostat culture (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 1077-1085 
    Details
    ISSN: 0006-3592
    Schlagwort(e): chemostat ; glucose limitation ; glycosylation ; CHO cells ; interferon-γ ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The physiology of a recombinant Chinese hamster ovary cell line in glucose-limited chemostat culture was studied over a range of dilution rates (D = 0.008 to 0.20 h-1). The specific growth rate (μ) deviated from D at low dilution rates due to an increased specific death rate. Extrapolation of these data suggested a minimum specific growth rate of 0.011 h-1 (μmax = 0.025 h-1) The metabolism at each steady state was characterized by determining the metabolic quotients for glucose, lactate, ammonia, amino acids, and interferon-γ (IFN-γ). The specific rate of glucose uptake increased linearly with μ, and the saturation constant for glucose (Ks) was calculated to be 59.6 μM. There was a linear increase in the rate of lactate production with a higher yield of lactate from glucose at high growth rates. The decline in the rate of production of lactate, alanine, and serine at low growth rate was consistent with the limitation of the glycolytic pathway by glucose. The specific rate of IFN-γ production increased with μ in a manner indicative of a growth-related product. Despite changes in the IFN-γ production rate and cell physiology, the pattern of IFN-γ glycosylation was similar at all except the lowest growth rates where there was increased production of nonglycosylated IFN-γ. © 1993 John Wiley & Sons, Inc.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bit.260420909
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  • 5
    Digitale Medien
    Digitale Medien
    Glucose-limited chemostat culture of chinese hamster ovary cells producing recombinant human interferon-γ (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 39 (1992), S. 327-335 
    Details
    ISSN: 0006-3592
    Schlagwort(e): Chinese hamster ovary ; interferon-γ ; chemostat culture ; glycosylation ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A Chinese hamster ovary (CHO) cell line expressing recombinant human interferon-γ (IFN-γ) was grown under glucose limitation in a chemostate at a constant dilution rate of 0.015 h-1 with glucose feed concentrations of 2.75 mM and 4.25 mM. The changes in cell concentration that accompanied changes in the glucose feed concentration indicated that the cells were glucose-limited. The cell yield on glucose remained constant, but there was a decline in residual glucose concentration and a reduced lactate yield from glucose in the latter stages of the culture. The consumption rates for many of the essential amino acids were increased later in the culture. The volumetric rate of interferon-γ production was maintained throughout the course of this culture, indicating that IFN-γ expression was stable under these conditions. However, the specific rate of IFN-γ production was significantly lower at the higher glucose feed concentration. Under glucose limitation, the proportion of fully glycosylated IFN-γ produced by these cells was less than that produced in the early stages of batch cultures. The proportion of fully glycosylated IFN-γ increased during transient periods of glucose excess, suggesting that the culture environment influences the glycosylation of IFN-γ.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bit.260390311
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  • 6
    Digitale Medien
    Digitale Medien
    Preparation and storage of ultra high purity hexane for solvent effect gas chromatographic analysis (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 561-564 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Trace analysis ; Solvent effect inlet technique ; Solvent purification ; Solvent storage ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240160913
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  • 7
    Digitale Medien
    Digitale Medien
    N-glycans of recombinant human interferon-γ change during batch culture of chinese hamster ovary cells (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 639-648 
    Details
    ISSN: 0006-3592
    Schlagwort(e): interferon ; glycosylation ; CHO cells ; microheterogeneity ; mass spectrometry ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A recombinant Chinese hamster ovary (CHO) cell line making human interfron-γ (IFN-γ) was grown in 12-L stirred tank fermentors in three batch fermentations under conditions of constant temperature, pH, and dissolved oxygen tension. In addition to cell growth, metabolite, and productivity data, a detailed analysis of the carbohydrate structures attached to each glycosylation site of IFN-γ was achieved using matrix-assisted laser desorption mass spectrometry (MALDI-MS) in combination with exoglycosidase array sequencing. Complex biantennary oligosaccharides (particularly Gal2GlcNAc4Man3 which was core ℵl-6 fucosylated at Asn25 but not at Asng97) were most prevalent at both glycosylation sites. However, considerable microheterogeneity arising from the presence of triantennary and truncated glycan structures was also observed. The proportion of the dominant core glycan structure (Gal2GlcNAc4Man3 ± Fuc1) decreased by 15-26% during batch culture, with increases in the proportion of oligomannose and truncated glycans over the same time period. Prolonged culture resulting from an extended lag phase led to further accumulation of oligomannose and truncated structures, reaching up to 52% of total glycans attached to Asng97 by 240 h of culture. The implications of these glycosylation changes for optimizing the time for harvesting cell cultures, and for the clearance of recombinant therapeutic products in vivo are discussed. © 1995 John Wiley & Sons, Inc.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bit.260480612
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  • 8
    Digitale Medien
    Digitale Medien
    Application of the fast-evaporation sample preparation method for improving quantification of angiotensin II by matrix-assisted laser desorption/ionization (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 1164-1171 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The fast-evaporation method of sample preparation has been applied for quantitative analysis using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. An instrumental protocol focusing on improvement of shot-to-shot repeatability and compensation for signal degradation has been developed for quantification of angiotensin II using the fast-evaporation technique and an internal standard. The fast-evaporation method was compared to the standard method of sample preparation (using a multicomponent matrix) in the quantitative analysis of angiotensin II, and found to be superior in several respects. Improvement in sample homogeneity using the fast-evaporation method enhanced both point-to-point repeatibility and sample-to-sample reproducibility. The relative standard deviations of the analyte/internal standard ratios (point RSD) were decreased by a factor of three compared to those obtained using the multicomponent matrix method. The average point RSD was found to be ca. 5% for the fast-evaporation technique. Two internal standards were evaluated for quantification of angiotensin II. The better one, 1-SAR-8-Ile angiotensin II, yielded a relative standard deviation of the standard curve slope of ca. 2.2% over two orders of magnitude of concentration (45 nM to 3000 nM), an improvement by a factor of two over the standard preparation method. Renal microdialysate samples, spiked with angiotensin II and the internal standard 1-SAR-8-Ile angiotensin II, were also analyzed using the fast-evaporation technique. The detection limit was calculated to be in the high attomole range (675amol). Furthermore, the accuracy for a single determination of angiotensin II concentration in these samples was found to be 13.9% with a relative error of 8.19%.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290091216
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  • 9
    Digitale Medien
    Digitale Medien
    Energy transfer limits in collisions with fast targets (1991)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 78-80 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The kinematics of ion/neutral collisions are analysed in terms of projectile and target kinetic energies and relative velocities. High (keV) center-of-mass collision energies are achievable for high-mass ions or neutrals colliding with keV target atoms, electrons or ions. The center-of-mass collision energy depends only very little on the fast-target mass. Applications in collisionally-activated dissociation of high-mass ions and neutrals are discussed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290050207
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  • 10
    Digitale Medien
    Digitale Medien
    252Cf plasma-desorption mass spectrometry of lipid a from Enterobacter agglomerans (1992)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 6 (1992), S. 616-622 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Endotoxins from gram-negative bacteria are believed to be causative agents of byssinosis, an occupational pulmonary disease associated with exposure to cotton dust in textile mills. Lipid A preparations from Enerobacter agglomerans, a gram-negative bacterium commonly found in cotton and cotton dust, have been analyzed using plasma-desorption mass spectrometry. Results indicate the existence of at least two lipid A types which differ only by the presence of an additional oxygen atom whose position has been localized to the acyloxyacyl ester-linked side-chain of the distal portion of the molecule. The lower molecular weight compound of the two structures has the same molecular weight and presumably the same empirical formula as a well-characterized lipid A from Salmonella minnesota. The mass spectra of lipid A compounds obtained from S. minnesota and E. agglomerans show strong similarities. Palmitoyl, hydroxymyristoyl, myristoyl, and lauroyl side-chains which are known to be prest in the former are inferred from spectral evidence to be present in the latter.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290061006
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