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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 46 (1979), S. 227-230 
    ISSN: 1432-0533
    Keywords: Subperineurial space ; Peripheral neuropathy ; Sural nerve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The size of the subperineurial space of the sural nerve has been evaluated quantitatively in 69 cases of various peripheral nerve diseases and in controls. A significant increase was found in beriberi neuropathy (6 cases) and idiopathic polyradiculoneuropathy (9 cases) as compared with the control (8 cases). On electron microscopy a few macrophages, fibroblast processes, collagen fibrils with a diameter of 50 nm, microfibrils with a diameter of 8 nm, and amorphous material were observed in both the enlarged subperineurial space and the endoneurial intercellular space. They were less frequently observed in controls. No significant correlation was found between the size of subperineurial space and the density of myelinated fibers.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0533
    Keywords: Isoniazid neuropathy ; Axonal degeneration ; Endoneurial edema ; Axonal swelling ; Dying back
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphometric studies of the pathologic changes were carried out on the peripheral nerves, spinal roots, and different levels of the Goll's tract in rats given isoniazid and killed 1, 2, 3, 4, 5, 6, 7, 14, and 30 days after intoxication. In teased fiber preparations, axonal degeneration was the main change present, and this was seen as early as day 2 in the peroneal and distal sural nerves. The frequency of myelinated fibers showing axonal degeneration was higher in the distal than the proximal sural nerve, and in the ventral than the dorsal root. In the group of rats killed on 5, 6, 7, and 14 days, a significant decrease of the myelinated fiber density was observed in the distal and proximal sural nerves, ventral root, and at the third cervical level of the Goll's tract. The degree of fiber degeneration was more severe in the distal than in the proximal sural nerve and in the third cervical than the fifth thoracic levels of the Goll's tract. Preferential decrease of large myelinated fibers was noted in all the affected nerves. No definite abnormalities, however, were seen in nerve cells of the 6th lumbar spinal ganglia and anterior horn cells of the lumbar spinal cord on light microscopy. On 30 days, regeneration at varying degrees was discerned in all the affected nerves with significant increase of small myelinated fibers, particularly in the ventral root. The findings indicate that both centrally and peripherally directed myelinated axons are more affected in the distal than in the proximal segments while the neuronal cell bodies are spatio-temporal evolution of this pattern of change is compatible with the concept of the “dying back” process or centralperipheral distal axonopathy.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0533
    Keywords: Multiple sclerosis ; Schwann cell ; Remyelination ; Glial fibrillary acidic protein ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To extend earlier observations on Schwann cell remyelination in multiple sclerosis (MS) lesions (Itoyama et al. 1983) we immunostained spinal cord sections from eight Japanese MS patients with antiserum to Po glycoprotein, a major constituent of peripheral nervous system (PNS) myelin, myelin basic protein (MBP), and glial fibrillary acidic protein (GFAP). Spinal cord sections from six of the eight Japanese MS patients contained large clusters of peripheral myelin sheaths with anti-Po immunoreactivity. In lesions found in four of the six patients, thousands of Po-stained PNS myelin sheaths were present. Necrosis was prominent in these lesions which included more than half of the spinal cord's transverse area. The number and density of regenerating myelin sheaths of peripheral origin were much greater than we observed in MS spinal cord lesions of white people (Itoyama et al. 1983). Anti-GFAP immunoreactivity was present in most brain and spinal cord lesions. However, the areas in lesions that contained large groups of PNS myelin sheaths lacked anti-GFAP immunoreactivity. Our data suggest that spinal MS lesions that are large, severely demyelinated, and partially necrotic may contain factors that inhibit fibrous astrogliosis. These factors, other substances in the large lesions and/or the lack of astrocytic scarring could then promote Schwann cell invasion, multiplication, and remyelination of surviving axons.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 72 (1986), S. 200-202 
    ISSN: 1432-0533
    Keywords: Adaxonal cytoplasm ; Schwann cell ; Myelinated fiber ; Spinal root
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The frequency of accumulation of 6-nm filaments in the adaxonal cytoplasm of Schwann cells in the 6th lumbar dorsal and ventral roots was evaluated in 4-, 8-, 26- and 45-week-old Sprague-Dawley rats. The frequency was higher in 4- and 8-week-old (growing) rats than in 26- and 45-week old (mature) rats, and also higher in ventral than in dorsal roots in 4-, 8- and 26-week old rats. There were no clusters on certain groups of myelinated fibers according to the size of transverse axonal area, in both the ventral and dorsal roots. Therefore, this accumulation may reflect certain functions of the adaxonal cytoplasm of Schwann cell during natural growth and maturation of the axon and myelin sheath.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 45 (1979), S. 43-45 
    ISSN: 1432-0533
    Keywords: Cerebrotendinous xanthomatosis ; Segmental demyelination ; Remyelination ; Sural nerve ; Onion bubl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a case of cerebrotendinous xanthomatosis (CTX), confirmed biochemically and histologically, quantitative histological studies of the biopsied sural nerve revealed significantly higher incidence of de- and remyelination and onion bulb than in controls. The density of total myelinated fibers fell within the range of controls, although the density of large myelinated fibers seemed to be slightly decreased. It was suggested that the preferential involvement of the myelin sheath and Schwann cell may exist in CTX.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0533
    Keywords: Isoniazid neuropathy ; Axonal degeneration ; Axonal swelling ; Paranodal demyelination ; Ventral root
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphometric sequential studies of pathologic changes were carried out on myelinated fibers in the lumbar ventral root of Sprague-Dawley rats administered with isoniazid, 1,500 mg/kg body weight, in a single dose. Accumulation of axoplasmic organelles with secondary paranodal retraction of myelin sheath occurred in the middle part of the ventral root as early as day 2 after the administration. On day 3, axonal degeneration started to occur, distal to the middle part, where the accumulation of axoplasmic organelles is prominent. Such accumulation with the possible blockade of the fast axoplasmic transport in the proximal axon may be directly responsible for the distal axonal degeneration. Alternatively such accumulation may be secondary to the distal axonal degeneration. The morphological sequential findings described clearly reflects the pathological events in isoniazid neuropathy.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0533
    Keywords: Mutant ; Quail ; Neurofilament ; Myelinated fiber ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The peripheral nervous system of a mutant of a Japanese quail deficient in neurofilaments (mutant) and of a normal Japanese quail (control) was morphometrically evaluated to characterize the morphological findings, especially those of the myelinated fibers of the mutant. In the proximal peroneal nerves, the frequency of the teased myelinated fibers showing the focal myelin thickening was higher in mutant than in control (P〈0.001) without obvious ongoing axonal degeneration and segmental demyelination. The total numbers of the myelinated fibers in the proximal and distal peroneal nerve, and in the tibial nerve branch to gastrocnemius muscle (pars medialis) were similar between control and mutant, although the number of the large myelinated fibers was less (P〈0.01) and the number of the small myelinated fibers was greater (P〈0.01) in mutant compared with control. The median diameters of neuronal cell bodies of the sacral dorsal root ganglia were similar in control and mutant. The percentages of light, dark and unclassified cells evaluated based on the histologic cytoplasmic features were also similar in control and mutant. Therefore, morphometric alterations were more pronounced in the peripheral myelinated nerve fibers compared with those in the cell bodies of the spinal dorsal root ganglia. We concluded that a smaller number of large myelinated fibers with a greater number of small myelinated fibers and the presence of focal myelin thickening are the main morphologic findings in this mutant, probably due to the arrest of radial growth or maturation of the axons of the myelinated fibers in the absence of ongoing myelinated fiber degeneration.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The crossover breakpoints for Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are located in the CMT1A-REP repeat flanking a 1.5-Mb region of chromosome 17p11.2–12. The precise locations of the breakpoints are heterogeneous, and we analyzed the relative frequency distribution of breakpoints in 33 unrelated Japanese CMT1A and 3 unrelated HNPP families. The CMT1A-REP repeat region was divided into five regions, A, B, C, D and E, based on restriction site differences between the proximal and distal CMT1A-REP repeats. The frequency distribution of breakpoints within the CMT1A-REP repeat in the Japanese patients was 3% in region A, 78% in B/C and 19% in D, which is similar to that in Caucasian patients. This result also indicates that an 8-kb region defined by region B/C is a recombinational hotspot within the CMT1A-REP repeat in Japanese patients.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1041
    Keywords: theophylline ; smoking ; sustained release formulation ; dosage forms ; multidose pharmacokinetics ; bioavailability ; circadian variation in kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and bioavailability of theophylline following 10 days of multiple doses of a plain uncoated (640 mg, q.i.d.) and a sustained-release tablet formulation (600 mg, b.i.d.) were related to habitual smoking in 11 healthy adult male volunteers, who had previously taken part in a single-dose study of an intravenous preparation of theophylline and of the same oral dosage form. There were significant differences (p〈0.05 to 0.01) in the steady-state mean and minimum theophylline concentration and AUC between the groups (6 smokers versus 5 nonsmokers), but not between other variables. A difference (p〈0.05) in peak time was also found between the dosage forms. The mean elimination t1/2 was significantly (p〈0.05) shorter in smokers than in nonsmokers. The intersubject variability in plasma theophylline concentration observed on the final trial day in the smoking group was larger and diverged more from simulation curves generated from the mean pharmacokinetic parameters of the single-dose study of the same formulations as compared to that of the nonsmoking group. There was no significant difference between the two groups in the mean accumulation ratio and absolute bioavailability of the two dosage forms. The mean morning (7 a.m.) trough theophylline concentrations after both formulations were significantly (p〈0.05 to 0.01) greater than the evening (7 p.m.) values within the same group. The average number of reported side-effects was significantly (p〈0.001) greater during the earlier period (Days 1 to 3) than the later period of the trial. A trend was observed suggesting that the incidence of side-effects was less in smokers than in nonsmokers. The results indicate that smoking is a determinant not only of enhanced elimination of theophylline but that it also produces more variability in the plasma level, irrespective of the dosage form administered or the dosing scheme employed. There may be circadian variation in theophylline kinetics.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1041
    Keywords: theophylline ; smoking habit ; absolute bioavailability ; pharmacokinetics ; sustained release preparation ; plain tablet preparation ; antipyrine pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability and pharmacokinetics of theophylline from a plain uncoated and 2 newly designed, sustained-release tablet formulations, as compared to intravenous aminophylline, were studied in 12 healthy adult male volunteers. The subjects were divided into two groups (n=6) with respect to smoking habit and on 4 separate occasions each received, on a randomized cross-over basis, a single dose of 400 mg equivalent of theophylline from every dosage form. The intravenous aminophylline study showed that habitual smoking had a significant (p〈0.05) effect on plasma theophylline clearance (0.051±0.006 vs 0.035±0.004 l/kg/h). Smoking significantly reduced the raw AUC from the 4 dosage forms (p〈0.05), but did not change the characteristics of absorption of each formulation. There was a non-significant trend towards reduced absolute bioavailability of theophylline from sustained-release formulations in smokers (percentage mean difference — 16% for one formulation and 13% for another). The trend was not observed for the plain uncoated tablet, which was rapidly absorbed (p〈0.01 to 0.05 in Ka, tmax and Cmax compared to sustained-release tablets). Similarity of the in vitro dissolution profiles of the two sustained-release formulations did not imply similarity of the in vivo absorption characteristics. Plasma clearances of theophylline and antipyrine were significantly correlated (p〈0.05,r=0.693,n=10). Thus, smoking enhanced the elimination of theophylline regardless of the dosage form administered. However, the extent to which habitual smoking may affect the hepatic first-pass effect on theophylline from sustained-release formulations requires further study. The results also suggest that theophylline and antipyrine may share a similar or common and presumably polycyclic hydrocarbon-inducible form(s) of microsomal drugmetabolizing enzyme.
    Type of Medium: Electronic Resource
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