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  • 1
    Electronic Resource
    Electronic Resource
    Late degradation simulation of poly(I-Lactide) (1994)
    Springer
    Journal of materials science 5 (1994), S. 575-581 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: High molecular weight as-polymerized poly(I-lactide) (PLLA) has been successfully used for fracture fixation and orbital floor reconstruction in animals and humans. As this PLLA takes more than 3 years to resorb, a method was developed to obtain insight into the final cellular degradation process of the PLLA by means of short-lasting animal experiments. Pre-degraded PLLA particles (〈 500 μm) were implanted subcutaneously in the backs of 14 rats. Two different methods of sterilization (regular steamsterilization and gamma-irradiation) and implantation vehicles (gelatin capsules and hydroxypropyl-methylcellulose (HPMC)) were used to examine the biological behaviour of the pre-degraded PLLA. Two rats were sacrificed at 48 h, 3 days and 1, 2, 4, 8, 16 weeks following the operation. The tissues were examined using light microscopy and transmission electron microscopy. Gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) were used to characterize the PLLA material. GPC measurements of the pre-degraded PLLA revealed a M n of 5500. Upon hydrolysation the crystallinity of the PLLA increased by about 60% and the heat of fusion was 86 J g-1. Deterioration of the mechanical and physical properties due to the two sterilization methods was negligible. No differences in cellular response were observed between the densely packed PLLA particles (gelatin capsules) and the particles scattered over the tissue (HPMC-gel). The present study enabled an early observation of the late degradation phase of PLLA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00120333
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  • 2
    Electronic Resource
    Electronic Resource
    Glycosaminoglycans and other sulphated polysaccharides in calculogenesis of urinary stones (1994)
    Springer
    World journal of urology 12 (1994), S. 43-48 
    Details
    ISSN: 1433-8726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Naturally occurring glycosaminoglycans (GAGs) and other, semisynthetic, sulphated polysaccharides are thought to play an important role in urolithiasis. Processes involved in urinary stone formation are crystallization and crystal retention. Oxalate transport and renal tubular cell injury are determining factors in these processes. In this article experimental results concerning the possible mechanisms of action of GAGs and other sulphated polysaccharides are reviewed. GAGs are inhibitors of crystal growth and agglomeration and possibly also of nucleation. They can prevent crystal adherence, correct an abnormal oxalate flux and prevent renal tubular cell damage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00182050
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  • 3
    Electronic Resource
    Electronic Resource
    Muscle spindles in rheumatoid arthritis (1979)
    Springer
    Virchows Archiv 382 (1979), S. 191-200 
    Details
    ISSN: 1432-2307
    Keywords: Rheumatoid arthritis ; Muscle spindles ; Neuromuscular spindles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural features of muscle spindles were studied in biopsy material from 100 patients suffering from classical rheumatoid arthritis. Thickening of the outer capsule, increased amount of extracellular ground substance within the inner capsule, and marked thickening of the basement membrane of capillary blood vessels supplying the muscle spindles were observed. Chronic inflammatory cells and macrophages were present within the spindles. Changes affecting the intrafusal muscle fibres were also seen. They were manifest as atrophy and degeneration of the intrafusal muscle fibres, absence of the specialised junctional complexes, and of the intercellular bridges, microladders and satellite cells. It is suggested that the changes affecting the intrafusal muscle fibres are probably secondary. Damage to the myelinated nerves was present, while the sensory and motor nerve endings were well preserved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01102874
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  • 4
    Electronic Resource
    Electronic Resource
    Muscle changes in rheumatoid arthritis (1977)
    Springer
    Virchows Archiv 373 (1977), S. 267-278 
    Details
    ISSN: 1432-2307
    Keywords: Rheumatoid arthritis ; Muscle changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscle changes were studied in biopsy material obtained from 100 patients suffering from classical rheumatoid arthritis. The abnormalities consisted of denervation atrophy of type II muscle fibres, degenerative changes in the sarcoplasm including presence of nemaline rods, and changes within the interstitium: namely perivascular nodular myositis, lymphocytic accumulations, different stages of vasculitis and abnormalities within the intramuscular nerves and muscle spindles. The muscles examined were always severely affected. It is considered that the simultaneous presence of these abnormalities is suggestive of rheumatoid arthritis. The importance of histochemical studies is emphasized. The literature concerning muscle changes in rheumatoid arthritis is reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432241
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  • 5
    Electronic Resource
    Electronic Resource
    Pt-Staining of peroxidatic reaction products at the ultrastructural level (1986)
    Springer
    Histochemistry and cell biology 84 (1986), S. 492-500 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The use of H2PtCl6 is proposed for the selective visualization of the poly-DAB reaction product created, in aldehyde-fixed tissue, with the cytochemical reaction according to Graham and Karnovsky (1966) or to Hoefsmit (1975). At sites known to contain peroxidatic activity, at the ultrastructural level, an electron-dense reaction product is acquired in otherwise unstained ultrathin sections. The presence of the element platinum in these sites has been demonstrated by X-ray microanalysis, for both the endogenous peroxidase and peroxidase conjugated to antibodies. The absolute platinum concentration has been established in erythrocytes and the granules in eosinophils and monocytes by co-embedded, Pt-containing Chelex ion-exchange beads next to the cells. By the application of the method of integrated morphometrical and chemical analysis (de Bruijn and Zeelen 1984; de Bruijn 1985; de Bruijn and Cleton 1985), both the elemental concentration and the area occupied have been calculated for eosinophil granules. The mean Pt net-intensity values of the cytoplasmic areas, known not to contain the enzyme peroxidase has been measured, and compared to the mean net-intensity Pt values of the granules. It was noted that the cytoplasmic Pt net-intensity values were not zero. The two sets of values are expressed as a mean Pt granule/cytoplasm ratio, this ratio creates a value for the “selectivity” of the reaction. The application of a postfixation reaction with OsO4-containing media, at pH 7.4, in addition to the H2PtCl6 reaction, resulted in a contrasted poly-DAB reaction product at all sites known to contain peroxidatic activity. However, X-ray microanalysis revealed that in addition to platinum, osmium was present. A reaction mechanism for the cytochemical poly-DAB contrast-staining at low pH, based upon the reaction proposed by Wild (1963), is postulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00482982
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural electron probe X-ray microanalytical reaction product identification of three different enzymes in the same mouse resident peritoneal macrophage (1989)
    Springer
    Histochemistry and cell biology 92 (1989), S. 243-253 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Simultaneous cytochemical enzyme localization procedures for peroxidase (PO) plus acid phosphatase (AcP-ase) and/or aryl sulphatase (AS) have been investigated at the ultrastructural (EM) level. Electron probe X-ray microanalysis (EPMA) will identify and differentiate the reaction products. Dual reaction product localization of PO plus AcP-ase or alternatively PO plus AS have been obtained in the same mouse resident peritoneal macrophage. This has been acquired by first performing a PO-reaction followed by AcP-ase or followed by AS. In both cases PO-related reaction products (PODAB/Os or PODAB/Pt) were localized in nuclear envelope (NE) and rough endoplasmic reticulum (RER). Cells were identified by this reaction product as resident macrophages. Reaction products from the AcP-ase related cerium (AcP-aseCe), localized in lysosomes have been identified and differentiated from the PO-related osmium containing products. Similarly AS related barium (ASBa), localized in lysosomal structures and (R)ER was identified and differentiated. Triple reaction product localization of PO followed by AcP-ase plus AS could also be obtained. In this case, PO-related platinum containing reaction products (PODAB/Pt or PODAB/Os) in NE and RER has been identified and differentiated from the AcP-ase related lysosomal cerium (AcP-aseCe) and the AS related barium localized in lysosomal and (R)ER structures. Reversing the sequences in both dual cytochemical procedures: AcP-aseCe or ASBa followed by PODAB/Os (or PODAB/Pt) resulted in AcP-aseCe or ASBa activity related reaction products only. Reversing the sequence in the triple reaction procedures (ASBa followed by AcP-aseCe) resulted in the absence of the barium containing reaction products. By application of OsO4 postfixation with aminotriazole (ATR) additives the detrimental effects upon the various precipitates have been confirmed. In LM studies, using rat intestine and non-metal identification reactions for two of the enzymes (pararosaniline for AcP-ase, DAB for peroxidase), the influences of the metal ions used in EM were tested on the appearance of the coloured reaction products. Cerium ions used in EM for detection of AcP-aseCe activity have been shown to influence the PODAB visibility in LM and EM experiments. From the AS reaction media components neither barium ions nor p-nitro catachol sulphate influenced the LM visibility of the PO reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00500925
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  • 7
    Electronic Resource
    Electronic Resource
    Sodium and calcium localization in cells and tissues by precipitation with antimonate: A quantitative study (1979)
    Springer
    Histochemistry and cell biology 63 (1979), S. 273-294 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Komnick's antimonate technique, which was devised to localize Na+ in cells and tissues, was studied quantitatively. Some modifications, as well as its application to Ca2+ localization, were also investigated. We combined measurements of Na+ and Ca2+ retention in plant roots during the various procedures, electron microscopy, autoradiography, and semiquantitative X-ray microanalysis. We were able to show that (at least in barley roots) antimonate does not precipitate at all with Na+, irrespective of the Na+ content of the tissue or the method of antimonate application. (Even during precipitative freeze dissolution or after freeze drying, no Na+ is precipitated.) By means of Komnick's antimonate technique Ca2+ is trapped within the tissue, but only after serious dislocation. Perspectives for reliable localization of diffusible ions in cells and tissues, by precipitation simultaneously with conventional fixations, are bad.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00490056
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  • 8
    Electronic Resource
    Electronic Resource
    Mitochondrial calcium of intact and mechanically damaged bone and cartilage cells studied with K-pyroantimonate (1979)
    Springer
    Histochemistry and cell biology 62 (1979), S. 325-336 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cellular cation was localized with K-pyroantimonate osmium fixation in whole fetal mouse metatarsal bones and in deliberately mechanically damaged specimens. X-ray microprobe analysis of ultrathin sections showed a positive correlation between the concentration of Ca (and Sb) and the amount of electron-dense precipitate. In non-damaged osteoblasts and growth-plate chondrocytes dense precipitate had accumulated along the plasmalemma and the mitochondrial membranes, whereas damaged cells showed the precipitate on round granules in the mitochondrial matrix but not on membranes. Intermediate stages between these two patterns were also found. In a non-calcifying tissue such as liver no membrane-bound precipitate was found in intact cells. However, damaged liver cells showed precipitate-containing mitochondrial granules similar to those in damaged bone cells, but only after incubation of the damaged tissue for l h in a Ca-containing balanced salt solution. Freezing of fresh whole bones in liquid N2 before fixation in K-pyroantimonate osmium did not change the precipitate pattern in the damaged cells, but in intact cells it produced a random distribution of precipitate unrelated to membranes. The results are compared with those obtained in other studies on the subcellular localization of calcium and in biochemical studies on membrane versus matrix loading in calcium-accumulating isolated mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00508360
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  • 9
    Electronic Resource
    Electronic Resource
    X-ray microanalysis of colloidal-gold-labelled lysosomes in rat liver sinusoidal cells after incubation for acid phosphatase activity (1980)
    Springer
    Histochemistry and cell biology 66 (1980), S. 137-148 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lysosomal apparatus of the Kupffer and endothelial cells of the sinusoidal lining of the rat liver was found to take up colloidal-gold particles with a mean diameter of 5 nm, prepared according to a modified method. After incubation of the glutaraldehyde-perfusion-fixed tissue in a lead-containing medium for the demonstration of acid phosphatase activity, a reaction product was observed in the gold-loaded lysosomes. By X-ray microanalysis of such lysosomes, the presence of osmium, gold and lead was detected qualitatively in the unstained sections from the tissue, which after the incubation had been post-fixed with an OsO4-solution to which K4Fe(CN)6 had been added to enhance the contrast. The quantitative computer-assisted processing of the X-ray microanalytical data from such lysosomes enabled to determine the gold-to-lead ratio and the individual gold and lead peak intensities derived from both the Mα and Lα values in the spectra. On the basis of these results and those obtained similarly in control lysosomes containing either only gold or only lead phosphate precipitate, it was found that only the Lα values were reliable, whereas the Mα values from the same lysosomal spectra were unrealistic, due to deconvolution problems in the computer programs applied. Based upon the Lα values it was found that among the population of lysosomes in single Kupffer cells, studied after a 60-min interval between the injection of the gold colloid and fixation, three types of lysosomal contents could be quantitated by X-ray microanalysis, viz. one type with only gold, one with only lead, one with gold and lead, in various ratios. This quantitative approach might make it possible to detect variations in lysosomal composition associated with ageing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00494641
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  • 10
    Electronic Resource
    Electronic Resource
    Scanning Electron Microscopic observations of endothelial changes in experimentally induced atheromatosis of rabbit aortas (1975)
    Springer
    Virchows Archiv 365 (1975), S. 23-40 
    Details
    ISSN: 1432-2307
    Keywords: Aortic Diseases ; Scanning Electron Microscopy ; Biological Transport ; Endothelial Cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following the administration of cholesterol for a period of 6–7 weeks, Scanning Electron Microscopic (S.E.M.) observations revealed mono-cellular, crater-like and dome-shaped endothelial changes on top of the large intimal plaques in the rabbit aortas. Finger-like and other shaped cell protrusions were observed at the edges of these crater-like and dome-shaped endothelial changes, giving the intimal plaques a rough appearance. At other sites, normal, smooth, although irregularly arranged, endothelial cells covered the lesions. By impregnating the cell borders with silver-nitrate or silver proteinate containing perfusates, it was possible in most cases to ascertain that the lesions were derived from changes in one cell or from changes in a small collection of cells. S.E.M.-observations further revealed crater-like and dome-shaped endothelial changes to be present in large fields or as isolated cell changes in normal areas at sites where no gross lesions were observed with the light microscope. In addition large, multi-cellular, crater-like endothelial changes were observed at the edges of the large intimal plaques. At these sites several endothelial cells were lacking, leaving behind a crater in which sometimes cells and a few fibrin threads were found. Following the administration of cholesterol for periods of 4–5 and 2–3 weeks similar monocellular changes were observed, some extending over large areas, others as single cells in apparently normal surroundings. Quantitatively the number of lesions was less than when the cholesterol was administered for a longer period. Transmission electron microscopic studies revealed the presence of large amounts of membrane-bound lipid globules in the subendothelial spaces and within some endothelial cells, structures which were assumed to be cross-sections of the crater-like or dome-shaped endothelial cell protrusions, visible with the S.E.M.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00439283
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