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  • 1
    Electronic Resource
    Electronic Resource
    Alterations in alanine metabolism in diabetic dogs during short-term treatment with an artificial B cell (1985)
    Springer
    Diabetologia 28 (1985), S. 763-768 
    Details
    ISSN: 1432-0428
    Keywords: Artificial B cell ; dog ; experimental diabetes ; alanine metabolism ; gluconeogenesis ; tracer study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The flux rates of plasma glucose and alanine were studied isotopically (6-3H-glucose and U-14C-alanine simultaneously) in resting chronically diabetic dogs during short-term treatment with an artificial B cell where the insulin was infused into a peripheral vein. Despite perfect blood glucose control and normal glucose flux rates, the concentration and rates of appearance and disappearance of alanine were significantly elevated in the diabetic animals before, during and after an exogenous glucose load. The incorporation of the carbon moiety of alanine into circulating glucose was also increased, but diminished to a near-normal extent when exogenous glucose was given. The plasma clearance rates for alanine in the diabetic dogs were normal throughout the study. It is concluded that normal blood glucose control in diabetes does not necessarily mean normalization of the entire metabolic network. On the basis of peripheral hyperinsulinaemia alanine formation from glucose and branched chain amino acids is elevated in muscle. This may explain increased flux of alanine despite normal blood glucose control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00265025
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  • 2
    Electronic Resource
    Electronic Resource
    Orinithine as a constituent of the peptidoglycan of Chloroflexus aurantiacus, diaminopimelic acid in that of Chlorobium vibrioforme f. thiosulfatophilum (1987)
    Springer
    Archives of microbiology 148 (1987), S. 72-76 
    Details
    ISSN: 1432-072X
    Keywords: Chlorobium ; Chloroflexus ; Cell wall ; Diaminopimelic acid ; Muramic acid-6-phosphate ; Ornithine ; Peptidoglycan-polysaccharide complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract L-Ornithine is the only diamino acid of the peptidoglycan of the gliding phototrophic Chloroflexus aurantiacus. The other constituents are L- and D-alanine, D-glutamic acid, N-acetyl-glucosamine and N-acetyl-muramic acid (in part as muramic acid-6-phosphate), all in approximate equimolar ratios to L-ornithine, aside from small amounts of glycine and histidine. Furthermore unlike typical Gram-negative bacteria, protein is not bound to this peptidoglycan. Instead, the rigid layer (sodium dodecyl sulfate insoluble cell wall fraction) contained large amounts of a complex polysaccharide consisting of sugar O-methyl ethers, hexoses and pentoses. Its binding site is presumably muramic acid-6-phosphate of the peptidoglycan. In contrast, in Chlorobium vibrioforme f. thiosulfatophilium, meso-diaminopimelic acid was found as the only diamino acid of this peptidoglycan. As with other Gramnegative bacteria, L- and D-alanine, D-glutamic acid, N-acetyl-glucosamine and N-acetyl-muramic acid (no muramic acid-6-phosphate) were observed in approximate equimolar ratios to meso-diaminopimelic acid, except a lower D-alanine content. The rigid layer of Chlorobium vibrioforme f. thiosulfatophilum contained protein, and there were no indications for a complex polysaccharide comparable to that of Chloroflexus aurantiacus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429651
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  • 3
    Electronic Resource
    Electronic Resource
    The lipopolysaccharide of the phototrophic bacterium Ectothiorhodospira vacuolata (1988)
    Springer
    Archives of microbiology 149 (1988), S. 245-248 
    Details
    ISSN: 1432-072X
    Keywords: Ectothiorhodospira vacuotata ; Lipopolysaccharide ; Lipid A ; DOC-PAGE ; Phototrophic bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The lipopolysaccharide of Ectothiorhodospira vacuolata was obtained by the phenol-water procedure. It contained a 3-O-methyl-hexose, glucose, galacturonic and glucuronic acids. The finding of d-glycero-d-mannoheptose and 2-keto-3-deoxyoctonate (tentatively identified) suggested a core-structure. The lipid fraction of the lipopolysaccharide contained phosphate and both, 2,3-diamino-2,3-dideoxy-d-glucose and d-glucosamine. The major fatty acids were amine-bound 3-OH-10:0 and 3-OH-12:0 and esterbound 14:0 and 16:0 Sodium deoxycholate gel-electrophoresis, showing a single band only, indicated R-type character of the lipopolysaccharide of Ectothiorhodospira vacuolata.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422012
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  • 4
    Electronic Resource
    Electronic Resource
    The lipopolysaccharide of the green sulfur bacterium Chlorobium vibrioforme f. thiosulfatophilum (1987)
    Springer
    Archives of microbiology 149 (1987), S. 125-129 
    Details
    ISSN: 1432-072X
    Keywords: Chlorobiaceae ; Chlorobium vibrioforme ; Degraded polysaccharide ; DOC-PAGE ; Lipid A ; Lipopolysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cell wall lipopolysaccharide of the green sulfur bacterium Chlorobium vibrioforme f. thiosulfatophilum was obtained by the phenol-chloroform-petroleum ether and the hot phenol-water methods, respectively. It contained mannose, glucose, galacturonic acid, glucosamine, glycine, and small amounts of rhamnose, galactose and glucuronic acid. In addition to d-glycero-d-mannoheptose, the corespecific constituents 2-keto-3-deoxyoctonate and l-glycero-d-mannoheptose were found. Polyacrylamide gel-electrophoresis in the presence of sodium deoxycholate gave no indication for the presence of O-specific repeating units. Degradation of the lipopolysaccharide required 10% acetic acid (100° C, 2 h). The lipid A moiety contained the total of glucosamine of the lipopolysaccharide as well as small amounts of 2,3-diamino-2,3-dideoxy-glucose. It was phosphate-free. The fatty acid spectrum comprised 3-OH-14:0, 3-OH-16:0, and iso-3-OH-18:0 besides little 12:0, 14:0 and 16:0. Hydroxylaminolysis and sodium methylate treatment revealed all of the three hydroxy fatty acids to be amidebound.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425077
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  • 5
    Electronic Resource
    Electronic Resource
    Near-field optical scanning microscopy in reflection (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 249-251 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The resolution of near-field optical scanning microscopy (NFOS) is determined by the dimensions of the microscopic light source rather than the diffraction limit. To demonstrate NFOS in reflection, intensity changes in the (backward) scattering from a 70–100 nm diam hole in a metal film were recorded while the sample was scanned in close proximity to this aperture. Raster-scan images of a planar metal test pattern yield a resolution comparable to the size of the aperture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99483
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  • 6
    Electronic Resource
    Electronic Resource
    Assessment of subcutaneous glucose concentration: validation of the wick technique as a reference for implanted electrochemical sensors in normal and diabetic dogs (1987)
    Springer
    Diabetologia 30 (1987), S. 940-945 
    Details
    ISSN: 1432-0428
    Keywords: Subcutaneous glucose concentration ; wick technique ; enzyme sensor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Employing saline-impregnated cotton threads, an implanted-wick technique was adopted in dogs to obtain specimen from the subcutaneous interstitial compartment in order to estimate its glucose concentration. By measuring the protein, potassium and haemoglobin contents, the centrifuged wick fluid was shown to contain the interstitial concentration of solutes after an equilibration time of approximately 15 min. In normal and in diabetic animals the steady state subcutaneous glucose concentration was almost identical to the circulating glucose level when ranged between 2 and 25 mmol/l. Slow alterations in the circulating glucose profile such as those which appear during an oral glucose tolerance test are closely mirrored by the respective levels in the wick fluid. Fast alterations, however, show deviations. The wick-based glucose levels are well paralleled by the current of Clark type glucose oxidase sensors implanted at the same site. Since, on the basis of in vitro calibrations the sensor outputs have only indicated apparent tissue glucose concentrations of between 70 and 90% of glycaemia, another reference is needed for calibration. Under steady state conditions, the wick method, and on this basis in routine measurements the blood glucose concentration, may be recommended as a reference of implanted sensors which can otherwise not be calibrated in situ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295878
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of prehepatic insulin administration on alanine flux rates in diabetic dogs (1987)
    Springer
    Diabetologia 30 (1987), S. 402-408 
    Details
    ISSN: 1432-0428
    Keywords: Alanine metabolism ; insulin-dependent diabetes ; dog ; isotopic study ; portal insulin infusion ; artificial B cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The in vivo flux rates of glucose (6-3H-glucose) and of alanine (U-14C-alanine) were measured in insulin-dependent chronically diabetic dogs which were infused with insulin employing a bedside-type artificial B cell and either the peripheral or the portal venous route. In comparison with non-diabetic control animals the diabetic dogs had near-normal patterns of glucose metabolism and pancreatic glucagon regardless of the route of insulin administration. They also showed reduced basal portal but moderately elevated peripheral insulin levels on peripheral and near-normal peripheral values on portal insulin infusion. Both concentration and production rates of alanine were reduced on peripheral (0.142±0.016mmol/l, 4.73±0.49 μmol·kg−1·min−1, p〈 0.05) but normal on portal insulin (0.206±0.030 mmol/l, 6.33±0.63 μmol·kg−1 ·min−1). The alanine clearance was slightly elevated or normal in the diabetic dogs, and the glucose production from alanine showed a strongly delayed response to an exogenous glucose load on either route of insulin administration. It is concluded that the peripheral hyperinsulinism during posthepatic insulin administration stimulates glucose utilisation to a normal extent, but inhibits the provision of amino groups in resting muscle. Alanine synthesis is thereby reduced, and the carbon moieties are shunted from glucose into circulating lactate. Long-term studies are needed to elucidate the role of the liver under these conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292542
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  • 8
    Electronic Resource
    Electronic Resource
    Automated feedback control of subcutaneous glucose concentration in diabetic dogs (1989)
    Springer
    Diabetologia 32 (1989), S. 573-576 
    Details
    ISSN: 1432-0428
    Keywords: Subcutaneous glucose ; enzyme electrode ; artificial B cell ; diabetic dog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The subcutaneous tissue is generally considered as a potential site for the monitoring of intracorporal glucose concentration by means of implanted sensors. We studied the suitability of using the resulting signal from the interstitial glucose concentration as an input in a feedback-controlled system for insulin administration. Miniaturized glucose electrodes (amperometric glucose oxidase sensors for the measurement of hydrogen peroxide) were implanted in insulin-dependent diabetic dogs. The output of these sensors was fed into the controller of a bedside-type artificial B cell. Insulin was infused by the device intravenously on the basis of a proportional-differential algorithm. The glucose patterns were compared to identical experiments where feedback control was accomplished on the basis of paracorporal blood glucose measurement using the same algorithm. Normoglycaemia was restored and maintained in both sets of experiments and oral glucose loads were well compensated for. It is concluded that the apparent subcutaneous glucose concentration is appropriate as an input signal for an artificial B cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285330
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  • 9
    Electronic Resource
    Electronic Resource
    Scanning near-field acoustic microscopy (1989)
    Springer
    Applied physics 48 (1989), S. 89-92 
    Details
    ISSN: 1432-0649
    Keywords: 16.16d ; 43.35d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Scanning near-field acoustic microscopy (SNAM) is a new method for imaging the topography of nonconducting surfaces at a potential lateral resolution in the sub-micron range. The basic element of this method is a distance sensor consisting of a sharply pointed vibrating tip, which is part of a high-Q quartz resonator driven at its resonance frequency. The decrease of the resonance frequency or of the amplitude of vibration when an object comes into the proximity of the tip serves as the important signal. The dependence of this signal on pressure and composition of the coupling gas shows that the hydrodynamic forces in the gas are responsible for the coupling between object and tip. The sensor is incorporated into a scanning device. Well-resolved line scans of a grating of 8 μm periodicity, a lateral resolution of 3 μm and a vertical resolution of 5nm have been achieved in our first experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694423
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