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  • 1990-1994  (5)
  • 1992  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 66 (1992), S. 700-705 
    ISSN: 1432-0738
    Keywords: Aluminum ; Toxicokinetics ; Rat ; Parenterals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The toxicokinetics of aluminum (Al) in male Wistar rats was studied after single intragastric (IG) doses of 1000 and 12000 μg Al/kg and intravenous (IV) doses of 10, 100, 1000, and 12000 μg Al/kg. Serial blood samples, daily samples of urine and feces as well as brain, liver, kidney, spleen, quadriceps muscle, and femur samples were collected. Al was measured by atomic absorption spectrometry. Al blood profiles after IV doses were adequately described by a two-compartment open model. Al toxicokinetics was dose dependent and appeared to plateau at 12000 μg/kg. At IV doses between 10 and 1000 μg/kg the terminal half-life of elimination from whole blood (t1/2β) increased from 29.9±7.8 to 209.3±32.6 min, and the total body clearance (CL) decreased from 2.45±0.64 to 0.28±0.03 ml min−1 kg−1. Following an IV bolus of 10 and 100 μg/kg the administered Al was recovered completely from urine (94.4%±9.9% and 98.5%±3.2%). Twenty-nine days after the IV dose of 1000 μg/kg daily renal excretion decreased to baseline values while only 55.1%±8.0% of the dose was excreted. Nineteen days after the single IV dose of 1000 μg/kg Al accumulated in liver (28.1±7.7 versus 1.7±0.5 μg/g of control rats) and spleen (72.5±21.1 versus 〈0.4 μg/g). After the single 1000 μg/kg IG dose no absorption of Al was detectable. The IG dose of 12000 μg/kg resulted in a maximum blood Al level of 47.9±12.4 μg/l after 50 min. The blood concentration time curve fitted a one-compartment open model with a half-life of absorption of 28.2±3.6 min and a t1/2β of 81.2±20.2 min. Cumulative renal Al excretion was 0.18%±0.10% of the dose and oral bioavailability was 0.02%. Seventeen days after the 12000 μg/kg IG dose the Al content in femur samples was increased (2.7±1.3 versus 0.6±0.4 μg/g). In no case was fecal elimination of incorporated Al observed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1440
    Keywords: Amalgam ; Lymphocytes ; Immune system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Dental amalgam has been considered to have adverse side effects on the immune system. Reports have been contradictory, indicating both an increase and a decrease in peripheral blood lymphocyte counts associated with amalgam restorations. We investigated two groups of patients, one of which was treated with amalgam restorations for the first time. In the other group, all existing amalgam fillings were removed. Prior to and after treatment, we determined the absolute and relative numbers of granulocytes, lymphocytes, monocytes, T cells, B cells, cytotoxic T cells, helper T cells and natural killer cells. In addition, functional investigations of T cells were performed. We failed to find any effect of amalgam restorations on the immune system in terms of the parameters investigated.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 98 (1992), S. 243-252 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neuron-specific enolase (NSE) immunocytochemistry was carried out in retinae of goldfish, axolotl, clawed frog, cane toad, lizard, chick, guinea-pig, rabbit, rat, cat and human. With the exception of Anura, strong immunoreactivity was seen in the large ganglion, amacrine cells and horizontal cells of the retina in all of the other species. Photoreceptors were found to be labelled in the rat and human retina and only one cone type in rabbit. Photoreceptor pedicles and ellipsoids were stained in the goldfish and the somata and inner segments of some photoreceptors in axolotl. In the axolotl retina, besides neurons, Müller cells (MCs) were also immunolabelled. In the retina of the cane toad and the clawed frog MCs were the only stained elements. Similarly in other parts of the central nervous system of the cane toad, glial elements of the optic tectum and spinal cord were immunoreactive. In contrast, in the peripheral nervous system, neurons of the 1st sympathetic ganglion and the 2nd dorsal root ganglion were labelled. In double-labelling experiments, glial fibrillary acidic protein and NSE showed colocalisation both in the glial elements of the optic tectum and spinal cord and in MCs of the retina of the cane toad.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0584
    Keywords: Interferon-γ ; Hematopoiesis ; γ/δ ; γ/δ T cells ; Cutaneous T-cell lymphoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recently we described a cutaneous T-cell lymphoma expressing the γ/δ T-cell receptor [5]. The patient suffering from this lymphoma showed low numbers of myeloid and T cells in peripheral blood, while B and NK cells were relatively increased. In vitro culture of the patient's bone marrow (BM) cells revealed a significant suppression of myeloid/monocyte colony formation (GM-CFU) compared with normal controls. This was not due to infiltration of the BM with lymphoma cells. We speculated that a soluble factor either secreted or induced by the lymphoma cells might be responsible for the marked suppression of hematopoiesis in this patient. From a skin biopsy with infiltrating γ/δ T-lymphoma cells we established T-cell clones bearing the γ/δ T-cell receptor and resembling the phenotype of the lymphoma cells. The supernatant (SN) of these γ/δ T-cell clones reduced the number of colonies in a CFU-GM assay (using normal control BM) in comparison to SN of α/β T-cell clones established from the same biopsy. This suppression was seen mainly on day 7 of culture and was not neutralized by the addition of placenta-CM. The main mediator of this suppression seems to be IFN-γ,since it was detectable in high amounts in the SN of these γ/δ T-cell tumor clones as well as in the serum of the patient. In addition, anti-IFN-γ antibodies can reverse the T-cell SN-mediated suppression of CFU-GM. We conclude that high serum levels of interferon-γ, which is secreted in high amounts from γ/δ T-cells grown from a biopsy of a cutaneous lymphoma, can suppress hematopoiesis.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 13 (1992), S. 197-206 
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: As part of an engineering analysis and experimental methodology to characterize prepreg tack, a compression-to-tension test was optimized to enhance reproducibility and generate intrinsic property data. With the resulting stress-strain compression and tension data, a theoretical model was developed to describe tack as a bulk viscoelastic property of a prepreg laminate stack. Using the viscoelastic analysis, four intrinsic material parameters to characterize prepreg tack could be defined. These were 1) relaxed modulus, 2) unrelaxed modulus, 3) relaxation time, and 4) initial void content of the prepreg stack. Relaxed and unrelaxed moduli of the prepreg stack were independent of temperature, while the relaxation time was highly dependent on temperature and matrix viscosity. In addition, the relaxation time was found to be influenced by resin/fiber content and prepreg surface characteristics, which also influenced the void content of the prepreg stack. Using these measured parameters, good agreement was observed between theory and experimental data for both the stress-strain curve of the tack test and the simplified compression tack index (CTI*), defined as the ratio of output energy of the prepreg stack during tensile unloading to input energy during compressive loading.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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