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  • 1
    Call number: 01-PR:129
    Pages: loose-leaf
    ISBN: 3-406-46880-2
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    01-PR:129 departmental collection or stack – please contact the library
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  • 2
    Abstract: OBJECTIVE: The aim of this work was to localize and quantify alterations of nerve microstructure in diabetic polyneuropathy (DPN) by magnetic resonance (MR) neurography with large anatomical coverage. METHODS: Patients (N = 25) with mild-to-moderate (Neuropathy-Symptom-Score [NSS]/Neuropathy Deficit Score [NDS] 3.8 +/- 0.3/2.6 +/- 0.5) and patients (n = 10) with severe DPN (6.2 +/- 0.6/7.4 +/- 0.5) were compared to patients (n = 15) with diabetes but no DPN and to age-/sex-matched nondiabetic controls (n = 25). All subjects underwent MR neurography with large spatial coverage and high resolution from spinal nerve to ankle level: four slabs per leg, each with 35 axial slices (T2- and proton-density-weighted two dimensional turbo-spin-echo sequences; voxel size: 0.4 x 0.3 x 3.5 mm(3) ) and a three-dimensional T2-weighted sequence to cover spinal nerves and plexus. Nerve segmentation was performed on a total of 280 slices per subject. Nerve lesion voxels were determined independently from operator input by statistical classification against the nondiabetic cohort. At the site with highest lesion-voxel burden, signal quantification was performed by calculating nerve proton spin density and T2 relaxation time. RESULTS: Total burden of nerve lesion voxels was significantly increased in DPN (p = 0.003) with strong spatial predominance at thigh level, where average lesion voxel load was significantly higher in severe (57 +/- 18.4; p = 0.0022) and in mild-to-moderate DPN (35 +/- 4.0; p 〈 0.001) than in controls (18 +/- 3.6). Signal quantification at the site of predominant lesion burden (thigh) revealed a significant increase of nerve proton spin density in severe (360 +/- 22.9; p = 0.043) and in mild-to-moderate DPN (365 +/- 15.2; p = 0.001) versus controls (288 +/- 13.4), but not of T2 relaxation time (p = 0.49). Nerve proton spin density predicted severity of DPN with an odds ratio of 2.9 (95% confidence interval: 2.4-3.5; p 〈 0.001) per 100 proton spins. INTERPRETATION: In DPN, the predominant site of microstructural nerve alteration is at the thigh level with a strong proximal-to-distal gradient. Nerve proton spin density at the thigh level is a novel quantitative imaging biomarker of early DPN and increases with neuropathy severity. Ann Neurol 2015;78:939-948.
    Type of Publication: Journal article published
    PubMed ID: 26381658
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  • 3
    Abstract: OBJECTIVES: The aim of this study was to evaluate whether high-resolution brachial plexus (BP) magnetic resonance neurography (MRN) is capable of (1) distinguishing patients with compressive neuropathy or noncompressive plexopathy from age- and sex-matched controls, (2) discriminating between patients with compressive neuropathy and noncompressive plexopathy, and (3) detecting spatial lesion patterns suggesting somatotopic organization of the BP. MATERIALS AND METHODS: Thirty-six patients (50.9 +/- 12.7 years) with clinical symptoms, nerve conduction studies, and needle electromyography findings suggestive of brachial plexopathy and 36 control subjects matched for age and sex (50.8 +/- 12.6 years) underwent high-resolution MRN of the BP. Lesion determination and localization was performed by 2 blinded neuroradiologists at the anatomical levels of the plexus trunks and cords. RESULTS: By applying defined criteria of structural plexus lesions on high-resolution MRN, all patients were correctly rated as affected, whereas 34 of 36 controls were correctly rated as unaffected by independent and blinded reading from 2 neuroradiologists with overall good to excellent interrater reliability. In all cases, plexopathies with a compressive etiology (n = 12) were correctly distinguished from noncompressive plexopathies with inflammatory origin (n = 24). Pathoanatomical contiguity of lesion from trunk into cord level allowed recognition of distinct somatotopical patterns of fascicular involvement, which correlated closely with the spatial distribution of clinical symptoms and electrophysiological data. CONCLUSIONS: Brachial plexus MRN is highly accurate for differentiating patients with symptomatic plexopathy from healthy controls and for distinguishing patients with compressive neuropathy and noncompressive plexopathy. Furthermore, BP MRN revealed evidence for somatotopic organization of the BP. Therefore, as an addition to functional information of electrodiagnostic studies, anatomical information gained by BP MRN may help to improve the efficiency and accuracy of patient care.
    Type of Publication: Journal article published
    PubMed ID: 28723713
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  • 4
    Abstract: OBJECTIVE: To detect and quantify lesions of the small-caliber sural nerve (SN) in symptomatic and asymptomatic transthyretin familial amyloid polyneuropathy (TTR-FAP) by high-resolution magnetic resonance neurography (MRN) in correlation with electrophysiologic and histopathologic findings. METHODS: Twenty-five patients with TTR-FAP, 10 asymptomatic carriers of the mutated transthyretin gene (mutTTR), and 35 age- and sex-matched healthy controls were prospectively included in this cross-sectional case-control study. All participants underwent 3T MRN with high-structural resolution (fat-saturated, T2-weighted, and double-echo sequences). Total imaging time was approximately 45 minutes per patient. Manual SN segmentation was performed from its origin at the sciatic nerve bifurcation to the lower leg with subsequent evaluation of quantitative microstructural and morphometric parameters. Additional time needed for postprocessing was approximately 1.5 hours per participant. Detailed neurologic and electrophysiologic examinations were conducted in the TTR group. RESULTS: T2 signal and proton spin density (rho) reliably differentiated between TTR-FAP (198.0 +/- 13.3, 429.6 +/- 15.25), mutTTR carriers (137.0 +/- 16.9, p = 0.0009; 354.7 +/- 21.64, p = 0.0029), and healthy controls (90.0 +/- 3.4, 258.2 +/- 9.10; p 〈 0.0001). Marked differences between mutTTR carriers and controls were found for T2 signal (p = 0.0065) and rho (p 〈 0.0001). T2 relaxation time was higher in patients with TTR-FAP only (p = 0.015 vs mutTTR carriers, p = 0.0432 vs controls). SN caliber was higher in patients with TTR-FAP vs controls and in mutTTR carriers vs controls (p 〈 0.0001). Amyloid deposits were histopathologically detectable in 10 of 14 SN specimens. CONCLUSIONS: SN injury in TTR-FAP is detectable and quantifiable in vivo by MRN even in asymptomatic mutTTR carriers. Differences in SN T2 signal between controls and asymptomatic mutTTR carriers are derived mainly from an increase of rho, which overcomes typical limitations of established diagnostic methods as a highly sensitive imaging biomarker for early detection of peripheral nerve lesions. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that MRN accurately identifies asymptomatic mutTTR carriers.
    Type of Publication: Journal article published
    PubMed ID: 28679600
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  • 5
    Abstract: OBJECTIVE: To evaluate functional and morphometric magnetic resonance neurography of the dorsal root ganglion and peripheral nerve segments in patients with Fabry painful neuropathy. METHODS: In this prospective study, the lumbosacral dorsal root ganglia and proximal peripheral nerve segments of the lower extremity were examined in 11 male patients with Fabry disease by a standardized 3T magnetic resonance neurography protocol. Volumes of L3 to S2 dorsal root ganglia, perfusion parameters of L5-S1 dorsal root ganglia and the spinal nerve L5, and the cross-sectional area of the proximal sciatic nerve were compared to healthy controls. RESULTS: Dorsal root ganglia of patients with Fabry disease were symmetrically enlarged by 78% (L3), 94% (L4), 122% (L5), 115% (S1), and 119% (S2) (p 〈 0.001). In addition, permeability of the blood-tissue interface was decreased by 53% (p 〈 0.001). This finding was most pronounced in the peripheral zone of the dorsal root ganglion containing the cell bodies of the primary sensory neurons (p 〈 0.001). Spinal nerve permeability showed no difference between patients with Fabry disease and controls (p = 0.7). The sciatic nerve of patients with Fabry disease at the thigh level showed an increase in cross-sectional area by 48% (p 〈 0.001). CONCLUSIONS: Patients with Fabry disease have severely enlarged dorsal root ganglia with dysfunctional perfusion. This may be due to glycolipid accumulation in the dorsal root ganglia mediating direct neurotoxic effects and decreased neuronal blood supply. These alterations were less pronounced in peripheral nerve segments. Thus, the dorsal root ganglion might play a key pathophysiologic role in the development of neuropathy and pain in Fabry disease.
    Type of Publication: Journal article published
    PubMed ID: 28835396
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  • 6
  • 7
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Almost all two-liquid phase bioprocesses are characterized by the presence of surface active materials (biosurfactants), which significantly influence the interaction between the phases. In order to predict mass transfer rates during cultivations of Pseudomonas oleovorans biosurfactant was isolated from the biosuspension and added in defined amounts to n-octane/water model-dispersions. Effects of biosurfactant concentration on interfacial tension, mean Sauter-diameter, drop size distribution, dispersion stability and liquid-liquid mass transfer coefficients were studied. A comparison was made between calculated solvent transfer rates (STR) and measured solvent uptake rates (SUR) of P. oleovorans cultures. With increasing interfacial surfactant concentration interfacial tension and mean Sauter-diameter decreased until a minimum for both, interfacial tension and mean Sauter-diameter, were reached. Interfacial tension measurements indicate that these minima have to be attributed to a maximum monomolecular surfactant concentration and the formation of polymolecular adsorption layers. Drop size distributions showed that, coalescence and droplet break-up disappear because droplets are stabilized by the biosurfactant adsorption layers at the interface. Mass transfer regime shifted from forced convection and surface renewal to diffusion. Comparison of solvent uptake rates (SUR) and solvent transfer rates (STR) showed that n-octane transfer usually will not be limiting P. oleovorans cultures, however, can become dominant in cultures where solvents with very low miscibilities like n-decane are used.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Many pseudomonads and other bacteria can grow on aliphatic and aromatic hydrocarbons that occur in the environment. We are examining the potential of such organisms as biocatalysts for the oxidation of a variety of substituted aliphatic and aromatic compounds. In order to attain a high production rate of oxidation products via such biotransformations, we have focused on two-liquid phase culture systems. In these systems cells are grown in liquid media consisting of an aqueous phase containing water soluble growth substrates and droplets of a water immiscible organic solvent containing bioconversion substrates and products. For industrial applications of such two-liquid phase processes, it is mandatory that these systems can be operated efficiently and safely. Therefore, the danger of an explosive atmosphere within the reactor, when using flammable organic solvents as substrates or products under aerobic conditions, must be considered. We have analyzed in detail four strategies to safely operate two-liquid phase cultivations. These include reducing the flammability of the organic solvent, operating within an explosion proof reactor, maintaining the operating pressure above a minimum level or maintaining the oxygen concentration within the reactor headspace and exhaust below a critical value. We conclude that technical means are available to operate two-liquid phase bioprocesses safely and efficiently.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1436-6215
    Keywords: Cadmium ; Zink ; Retention ; Futter ; Hühnerküken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The influence of zinc content in the diet on cadmium retention in the liver and kidney was studied in growing chicks. Cadmium and zinc concentrations used were similar to those occurring in normally feeds. Increasing cadmium levels in feeds resulted in increasing cadmium concentrations in organs. The cadmium levels in liver were about half as high as in kidneys. Physical conditions and growth rate of the chicks remained unaffected by the cadmium feeding. Cadmium retention in liver and kidneys was related to the zinc content of the diet. Feeding zinc-deficient diets resulted in a 40% higher cadmium retention than feeding adequate zinc diets (50 mg/kg). Excessive zinc levels had no additional effect on cadmium retention.
    Notes: Zusammenfassung In einem Versuch mit Hühnerküken wurde der Einfluß einer unterschiedlichen Zinkversorgung auf die Cadmiumretention in Leber und Nieren untersucht. Es wurden Cadmium- und Zinkkonzentrationen im ernährungsphysiologisch relevanten Bereich eingesetzt. Mit steigendem Cadmiumgehalt im Futter erhöhte sich auch die Cadmiumkonzentration in den Organen. In der Leber wurden etwa halb so hohe Konzentrationen gemessen wie in den Nieren. Der Gesundheitszustand und die Mastleistung der Küken blieben vom Cadmiumgehalt des Futters unbeeinflußt. Es bestand eine deutliche Abhängigkeit der Cadmiumretention in Leber und Nieren vom Zinkgehalt des Futters. Bei adäquater Zinkversorgung (Zusatz von 50 mg Zink/kg Futter) wurden in den Organen gegenüber marginaler Zinkversorgung (ohne Zinkzusatz) um bis zu 40 % verminderte Cadmiumrückstände beobachtet. Eine Überversorgung mit Zink konnte diesen Effekt nicht verstärken.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied optical transitions in GaInN/GaN single and multiple quantum wells using time-resolved photoluminescence spectroscopy. Our results show that the energy positions of the dominant emission lines strongly depend both on the well width and on the number of wells. In the case of multiple quantum wells, time-resolved measurements clearly distinguish multiple emission lines. These observations are consistently explained by considering the large built-in piezoelectric field in strained GaInN quantum wells. The multiple emission lines are attributed to intra- and interwell transitions between nearest and next-nearest neighbors. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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