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  • 1
    ISSN: 1432-198X
    Schlagwort(e): Key words Chronic renal failure ; Insulin-like growth factors ; Insulin-like growth factor binding proteins ; Growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Growth retardation in children with chronic renal failure (CRF) is partly due to an inhibition of insulin-like growth factor (IGF) activity by an excess of high-affinity IGF-binding proteins (IGFBPs). The aim of this study was to analyze the serum levels and forms of IGFBP-4 and IGFBP-5 in CRF patients using specific, recently developed radioimmunoassays (RIAs) and immunoblot analysis. We examined 89 children [age 11.5 (2.8–19.0) years] with CRF [glomerular filtration rate 26.6 (7.0–67.4) ml/min per 1.73 m2], nine of them with end-stage renal disease undergoing peritoneal dialysis. Serum-immunoreactive IGFBP-4 levels were fourfold increased in CRF (prepubertal 1080±268 ng/ml; pubertal 989±299 ng/ml) compared to healthy prepubertal controls (265±73 ng/ml). In contrast, serum IGFBP-5 levels were not significantly increased neither in prepubertal (361±120 ng/ml vs 282±75 ng/ml in controls) nor pubertal CRF children (478±165 ng/ml vs 491±80 ng/ml in controls). Immunoblot analysis showed the presence of intact as well as fragmented IGFBP-4 and IGFBP-5. Serum IGFBP-4, but not IGFBP-5, levels were inversely correlated with GFR (r=–0.39, P〈0.001). In prepuber- tal children, IGFBP-4 levels were inversely correlated with standardized height (r=–0.40; P〈0.005). In contrast, IGFBP-5 levels were positively correlated both with standardized height (r=0.32, P〈0.02) and baseline height velocity (r=0.45, P〈0.005). A 3-month therapy with rhGH stimulated serum IGFBP-5 levels by 43% (P〈0.01); there was no consistent effect on IGFBP-4 levels. There was a positive correlation between IGFBP-4 and IGFBP-2 (r=0.46, P〈0.001); IGFBP-5 was positively correlated with IGF-I (r=0.59, P〈0.001), IGF-II (r=0.42, P〈0.001) and IGFBP-3 (r=0.47, P〈0.001) and inversely correlated with IGFBP-1 (r=–0.41, P〈0.001). In summary, serum IGFBP-4 is fourfold elevated in children with CRF in relation to the degree of renal dysfunction and contributes to the marked increase in IGF-binding capacity in CRF serum. The inverse correlation of serum IGFBP-4 with standardized height is consistent with its role as another inhibitor of the biological action of the IGFs on growth plate cartilage. In contrast, serum IGFBP-5 is not elevated in CRF serum and circulates mainly as proteolysed fragments. The positive correlation of serum IGFBP-5 with growth and its increase during GH therapy indicate that IGFBP-5 is a stimulatory IGFBP in patients with CRF, either by enhancing IGF activity through better presentation of IGF to its receptor or by an IGF-independent effect through activation of a specific, recently described putative IGFBP-5-receptor.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1432-1076
    Schlagwort(e): Chronic renal failure ; Recombinant human growth hormone treatment ; Insulin-like growth factors ; Insulin-like growth factor binding proteins ; Progression of renal disease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Impaired growth and stunting remains a major therapeutic problem in children with chronic renal failure (CRF). Recombinant human growth hormone (rhGH) treatment may be beneficial, but concern has been raised about possible side-effects, i.e. deterioration of renal function and glucose intolerance. We have treated 10 prepubertal children with CRF (median age 7.5 [1.7–10.0] years) with 4 IU rhGH/m2 per day s.c. over a period of 1 year. Height velocity increased significantly (P〈0.03) from basal 4.6 (2.0–14.0) cm/year to 9.7 (6.8–17.6) cm/year. Height velocity SDS for chronological age and for bone age increased in all children from basal median −2.3 to +3.8 (P〈0.005). Median glomerular filtration rate (GFR) measured by single injection inulin clearance at onset was 18 (11–66) ml/min per 1.73 m2 and did not change significantly during the treatment year. The loss of GFR as estimated by creatinine clearance was similar during the treatment year (median loss 1.3 ml/min per 1.73 m2) compared to the year before treatment (median loss 3.7 ml/min per 1.73 m2). Serum glucose levels during an oral glucose tolerance test did not change, but fasting as well as stimulated insulin levels increased significantly with time during the study period. It is concluded that the rhGH regimen employed was remarkably effective in improving growth velocity in children with CRF without adversely affecting GFR. Glucose homeostasis remained stable, but at the expense of increased serum insulin levels.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1437-160X
    Schlagwort(e): Key words Insulin-like growth factors ; Insulin-like growth factor binding proteins ; Rheumatoid arthritis ; Articular cartilage ; Proteoglycans
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The objective of this study was to quantify insulin-like growth factor (IGF) binding proteins (IGFBPs) in the synovial fluid (SF) and plasma of patients with rheumatic diseases and to study the role of these proteins in the regulation of cartilage proteoglycan (PG) synthesis. Immunological determination of IGFBP-2, IGFBP-3, IGF-I, IGF-II, interleukin-1β (IL-1β) and tumour necrosis fac-tor α (TNFα) was undertaken in the SF and plasma of 115 patients with rheumatoid arthritis (RA; n = 53), osteoarthritis (OA; n = 44) and other rheumatic disorders. We also determined the effects of SF on bovine cartilage PG synthesis in culture. IGFBP-2 and IGFBP-3 were elevated in the plasma (by 38% and 28%, respectively) and SF (by 56% and 59%, respectively) of patients with RA compared to age- and sex-matched OA controls (determined by RIA and confirmed by Western ligand blot). IGF-I and IGF-II did not differ significantly between the two groups. OA SF, and, to a lesser extent, RA SF stimulated cartilage PG synthesis in culture, and more than 60% of this activity was neutralised by a specific monoclonal anti-IGF-I antibody. Human IGFBP-3 dose-dependently inhibited the stimulation of cartilage PG synthesis effected by SF or human IGF-I. In RA patients, the SF concentration of IGFBP-3 was positively correlated with SF levels of IL-1β and TNFα, with the serum level of C-reactive protein and with the erythrocyte sedimentation rate. We concluded that IGF-I is, under the conditions studied, the most important anabolic factor in human SF with respect to articular cartilage PG synthesis. The bioactivity of IGF-I in joints is modulated by IGFBP-3, which is elevated in RA SF compared to OA SF. Elevated IGFBP-3 in RA SF may reduce the availability of IGF-I to articular chondrocytes, thus interfering with cartilage PG synthesis in RA.
    Materialart: Digitale Medien
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  • 4
    ISSN: 0887-6134
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A tandem mass spectrometric method is described which allows the assignment of stereochemistry to fragment ions comprising intact sugar subunits of larger glycosides without chemical degradation and product isolation by chromatography. The approach relies on the mass selection of the ‘sugar ion’ of interest followed by analysis of stereoselective fragmentation induced by low-energy collisional activation. The daughter ion spectra provide configurational fingerprints of the selected sugar ions which can be matched for identity with reference spectra obtained from suitable precursors of known stereochemistry. Glucose, mannose and galactose furnished the required set of the most important reference ions. By using peracetyl (and perdeuterioacetyl) derivatives, galactose was readily identified as the glycosidic sugar constituent of the (known) antibiotic papulacandin B and a further (unknown) congener.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 14 (1983), S. 98-105 
    ISSN: 0933-5137
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Beschreibung / Inhaltsverzeichnis: Characterisation of Adherence of Precious Alloy to Dental CeramicLaminated metal-ceramic composites were produced from two Aubase alloys and two ceramic powders. For part of the specimen an extra Aurich layer was brought into the metal-ceramic interface. Microscopic investigations showed enrichment of non precious alloying elements in the metallic region adjacent to the interface and a sheet of enhanced porosity (about 5-15%) in the ceramic region adjacent to the interface. After producing a Chevron notch in the interface the composite specimens were fractured in a controlled mode in four point bending. As the crack was at least partly running along the ceramic zone of enhanced porosity near the interface, the average crack resistance R̄ of the interface could be determined. In specimens without an extra Au-rich layer R̄ was between 3 and 12 J/m2 and thus less than the R̄-value of the ceramic (R̄ 12 J/m2). The relatively large scatter is supposed to be mainly due to internal stresses. Specimens containing an extra Au-rich layer showed high R̄-values (up to 36 J/m2) due to good interlocking of metal and ceramic.
    Notizen: Aus zwei Edelmetall-Aufbrennlegierungen und zwei keramischen Massen der Dentaltechnik wurden Metall-Keramik-Schichtverbundproben hergestellt, wobei bei einem Teil der Proben zusätzlich eine goldreiche Schicht zwischen die Verbundpartner eingebracht wurde. Die mikroskopische Untersuchung zeigte, daß sich metallseitig an der Grenzfläche unedle Legierungsbestandteile angereichert hatten und keramikseitig eine flächenhafte Zone erhöhter Porosität (etwa 5-15%) gebildet wurde. Die in der Grenzfläche mit einem Spitzkerb versehenen Proben wurden im Vierpunktbiegeversuch bei Raumtemperatur kontrolliert gebrochen. Der Riß verlief zumindest teilweise in der grenzflächennahen, porösen Zone der Keramik, so daß der mittlere Rißwiderstand R̄ der Grenzfläche bestimmt werden konnte. Für Proben ohne goldreiche Zwischenschicht lag R̄ zwischen 3 und 12 J/m2 und damit in der Regel niedriger als in der Keramik (etwa 12 J/m2). Die relativ große Streuung wird vorwiegend auf herstellungsbedingte innere Spannungen zurückgeführt. Für die hohen R̄-Werte der Proben mit goldreicher Zwischenschicht (bis 36 J/m2) wird die gute Verzahnung zwischen Metall und Keramik als ursächlich angesehen.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 8 (1985), S. 718-726 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary columns, glass ; Inert, stable stationary phases ; Leaching ; Immobilization by condensation ; OH terminal groups ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Coating intensively leached silica surfaces with OH-terminated phases provides a new way of producing, by simple means, columns with substantially increased inertness and thermostability. In addition, their separation efficiency is found to be typically higher than that of columns with traditional coatings. The underlying basic effect is a condensation process between terminal silanol groups of the phase and residual silanols, of the glass surface, thus producing the mentioned inertness. Moreover, the surface-bonded molecules are immobilized without addition of a radical generator. If required, crosslinking can also be effected using a volatile azo compound. No vinyl groups are required for this additional immobilization process. The paper discusses all processes involved, and gives detailed working directions for the following medium polar phases. OV-1701-OH, OV-31-OH (new, 17% cyanopropyl), OV-61-OH, and OV-17-OH, and the apolar phases PS-347.5 and PS-086. There is no doubt so far that the principle of terminal silanol groups is applicable to all silicone phases, and may replace the traditional endcapped stationary phases in the future.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 9 (1986), S. 120-121 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary columns, glass ; Persilylation ; Polar, inert columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 9 (1986), S. 426-428 
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary columns, glass ; OV-240-H, 33% cyanopropyl ; Immobilization by condensation ; Crosslinker, dimethyltetramethoxysiloxane ; in situ methylation, diazomethane ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Coating intensely leached glass capillaries with OV-240-OH, the most polar commercially available OH-terminated polysiloxane phase at the present time, is described. Beside chemical bonding of the phase via condensation with silanol groups of the support, additional immobilization using dimethyltetramethoxysiloxane as a crosslinker is carried out. After in situ methylation of the immobilized coating, and transformation of acidic impurities of the cyanopropyl substituted phase into the respective methyl esters, increased inertness of the column was observed. Working instructions are given, and processes involved are discussed.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 472-476 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography, high temperature ; Capillary columns, glass ; OH-terminated polysiloxane, PS-089 ; Immobilization by condensation ; Crosslinker, methyltrimethoxysilane ; Analysis of antioxidants and UV-stabilizers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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