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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 196 (1997), S. 465-476 
    ISSN: 1432-0568
    Keywords: Key words Pharyngeal motoneuron ; Cytoarchitecture ; Retrograde tracing study ; Swallowing ; Synaptology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We investigated the fine structure of the semicompact formation of the nucleus ambiguus (AmS), which was identified by retrogradely labeled pharyngeal (PH) motoneurons. When cholera toxin subunit B-conjugated horseradish peroxidase was injected into the lower pharyngeal muscle, many retrogradely labeled PH neurons were found throughout the AmS. Besides the PH neurons, two types of neurons were recognized in the AmS: unlabeled medium-sized neurons and unlabeled small neurons. The PH neuron was large (27.6 × 44.1 μm) and polygonal, and contained many Nissl bodies and well-developed cell organelles with a prominent spherical nucleus. The medium-sized neuron was dark and oval (19.3 × 33.2 μm), and contained many free ribosomes and much swollen rough endoplasmic reticulum with a distorted oval nucleus. The small neuron was spindle-shaped (12.3 × 20.2 μm), and had poorly developed cell organelles with an irregularly shaped nucleus. The average number of axosomatic terminals in a sectional plane was largest in the PH neurons (32.8), smaller in the medium-sized neurons (23.1), and smallest in the small neurons (6.3). The number of axo-somatic terminals containing round vesicles (Gray’s type I) was almost equal to that of terminals containing pleomorphic vesicles (Gray’s type II) in the PH neuron, and slightly smaller in the small and the medium-sized neurons. About 60% of the axodendritic terminals were Gray’s type I, and 40% were type II. These results indicate that there are two different types of interneurons besides the PH motoneurons in the AmS.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0568
    Keywords: Key words Intrinsic laryngeal motoneurons ; Cholera toxin HRP ; Ultrastructure ; Swallowing ; Respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The laryngeal motoneurons innervating the cricothyroid muscle (CT) are located in the semicompact formation just ventral to the rostral part of the compact formation of the nucleus ambiguus. The motoneurons innervating the posterior cricoarytenoid muscle (PCA) are located in the loose formation. We retrogradely labeled the CT and the PCA motoneurons using cholera toxin subunit B-conjugated horseradish peroxidase, and determined the ultrastructure and synaptic organization of these neurons. The CT and the PCA motoneurons had the appearance of α-motoneurons, i.e., large, oval or polygonal cells containing well-developed organelles and a prominent spherical nucleus. Two kinds of neurons were recognized among the PCA motoneurons. The one (PCA-A) was significantly smaller than the other (PCA-B). The average number of axosomatic terminals in a section was significantly largest in the PCA-B (56.6), smaller in the PCA-A (36.0), and smallest in the CT (32.3) neurons. Most of the axosomatic terminals (64.7%) contained pleomorphic vesicles and made symmetric synaptic contacts (Gray’s type II) with the PCA-A neurons, while more than 60% contained round vesicles with asymmetric synaptic contacts (Gray’s type I) in the CT (69.5%) and the PCA-B (60.6%) neurons. A few terminals associated with subsurface cisterns were present on all laryngeal motoneurons. These results indicated that the CT motoneurons may receive mostly excitatory terminals, whereas the PCA muscle may be regulated by neurons having many inhibitory terminals, and neurons having many excitatory terminals.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1076
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 139 (1997), S. 851-856 
    ISSN: 0942-0940
    Keywords: Apoptosis ; bromocriptine ; octreotide ; somatotropinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Octreotide is a potent agonist of somatostatin that lowers the serum level of growth hormone (GH), and reduces the size of somatotropinomas. However, the detailed mechanism of shrinkage of this tumour is not known. We, therefore, evaluated 11 patients with somatotropinomas who were treated with octreotide 300 μg/day for 2–5 weeks to observe the morphological changes in the tumour using electron microscopy and the immunocytochemical study of apoptosis using polyclonal anti-single stranded DNA. Findings were compared with those obtained with bromocriptine treatment (10 mg/day, 2 weeks) of 5 patients with somatotropinomas, and 11 patients who received no preoperative treatment (control group). The octreotide group showed neither increase in stromal tissue nor cell death. The size of tumour cells appeared to be slightly reduced. No typical apoptotic bodies were seen on the electron micrographs. The apoptotic index in the octreotide group (0.40 ± 0.60%; mean ± SD) resembled that in the control group (0.81 ± 0.79%). In contast, the bromocriptine group showed some cell death and an increase in stromal tissue. The bromocriptine group also showed the apoptotic index which (20.1 ± 14.8%) was significantly higher than that of the control group (0.81 ± 0.79%). Thus, octreotide did not induce apoptosis in somatotropinomas despite the presence of tumour shrinkage. Because of the lack of fibrosis observed in the octreotide-treated tumours, the preoperative administration of octreotide may help to improve the outcome of the transsphenoidal operation.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0942-0940
    Keywords: Keywords: Cortical stab wound; macrophages; microglial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To examine the cellular dynamics of macrophages and microglial cells in response to cerebral injury, we studied the brain adjacent to cortical stab wounds in young adult rats. Brains were obtained 30 min after intravenous infusion of bromodeoxyuridine (BrdU) on one day (day 1) to 28 days (day 28) after wounding. Brain sections were double-labelled immunohistochemically for monocyte/macrophage antigen ED1 and for BrdU. ED1-positive (ED1+) cells were classified morphologically into two groups, ED1+L and ED1+S cells, representing macrophages and microglial cells, respectively. ED1+L cells appeared on day 1 after wounding and rapidly increased in number to reach a maximum on day 3, but quickly disappeared by day 5. ED1+S cells also appeared on day 1, but the increase in number was slower, reaching a maximum only on day 7. ED1+L cells were all negative for BrdU, but some ED1+S cells were stained for BrdU, evidence of proliferation. The present investigation demonstrated different cellular dynamics for macrophages and microglial cells responding to a stab wound, and also indicated differing sources for the two cell type. It may be possible to prevent the accumulation of these cells which are harmful to the brain in reducing the damage suffered.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0942-0940
    Keywords: Blood-brain barrier ; irradiation ; radiosurgery ; serum albumin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied the effect of high-dose single-fraction irradiation on the permeability of the blood-brain barrier (BBB) in rat brains. Immunohistochemistry with an antibody to serum albumin was used as a sensitive method for detecting the extravasation of endogenous serum components. Extravasation of albumin was detected as early as 1 day after irradiation with 20 or 40 Gy. Immunoreactivity reached its maximum after 3 days, gradually decreased during the following few weeks and had disappeared by day 30. Extravasation was much greater after irradiation with 80 Gy and continued to increase during the whole period of the experiment (6 days). Disruption of BBB this early after irradiation has not been previously documented. The time course of observed serum albumin extravasation, however, agrees well with the previous ultrastructural evidence for increased BBB permeability after irradiation with 27 Gy in monkey brains4. This transient impairment of BBB may contribute to the reversible neurological symptoms after radiosurgery. It may also allow drugs that normally not pass the BBB to do so and thus disperse in the brain when administered at this time.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0942-0940
    Keywords: TNF-binding sites ; gliomas ; endothelial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To identify the cellular targets of TNFα in human gliomas, a total of 30 surgical specimens (12 glioblastomas, 4 anaplastic astrocytomas, 3 astrocytomas, 7 brains adjacent to tumour (BAT), 4 histologically normal-appearing brains) were examined by in vitro binding technique using biotinylated TNFa. The TNF-binding sites (TNF-BS) were recognized in the tumour cells in 8 of the 12 glioblastomas. 3 of the 4 anaplastic astrocytomas and in all the 3 astrocytomas. The TNF-BS were also recognized in the vascular endothelial cells in all these cases. The presence of TNF-BS in blood vessels ranged from 7.7 to 74.4% of the background vessels. This wide range of variation in the presence of TNF-BS within the tumour cells and tumour blood vessels may be relevant to the variable response of individual tumours to TNFα therapy. Since the tissue of normal brain, which lacks TNF-BS, might hardly be affected by this cytokine, administration of TNFa may be considered as an adjuvant therapy in selected groups of patients.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0942-0940
    Keywords: Ki-67 ; PCNA ; pituitary adenoma ; tumour doubling time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to improve our ability to predict the regrowth of nonfunctioning pituitary adenomas, we tried to assess the correlation between growth fractions with Ki-67 and PCNA (proliferating cell nuclear antigen) and tumour doubling times in regrowing tumours, and also to find out any difference of growth fractions between the regrowing and the cured cases. In 33 patients with non-functioning pituitary adenomas, 14 cases including 11 with cavernous sinus invasion showed residual tumour on MRI after the operation (regrowing group) and 19 cases had no tumour regrowth on MRI within 5 years after the operation (cured group). Immunocytochemical studies were done with monoclonal antibodies (anti-PCNA, anti-Ki-67: MIB-1). The growth fraction of each tumour was estimated by calculating the ratio of the positive nuclei to the total number of tumour cells with the aid of an image analyser (Mac SCOPE). The tumour doubling times were estimated from serial CT or MRI with the aid of the image analyser (NIH image). Ki-67 staining indices ranged from 0.2% to 1.5% (n = 14, 0.86±0.10%; mean±SEM) in the regrowing group, and from 0.1% to 0.5% (n = 19, 0.23±0.03%) in the cured group. PCNA staining indices of the regrowing group ranged from 0.6% to 24% (n = 14, 3.7±1.6%). In the regrowing group, the tumour doubling times ranged from 200 to 2550 days (930±180 days), and showed a significant inverse correlation with Ki-67 staining indices, but no correlation with PCNA staining indices. The regrowing group showed a significantly higher Ki-67 staining index (n = 14, 0.86±0.10%) than the cured group (n = 19, 0.23±0.03%) (p〈0.01). These results indicate that immunocytochemical studies using MIB-1 may be better than those with PCNA for the prediction of regrowth in non-functioning pituitary adenomas. Immunocytochemical study with MIB-1 could lead to the accurate prediction of the rapid regrowing lesions in non-functioning adenomas.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0942-0940
    Keywords: Aneurysm ; anti-single-stranded DNA antibody ; apoptosis ; DNA fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pathological specimens were collected from 14 unruptured and 13 ruptured aneurysms at the time of clipping and studied in order to assess the underlying mechanism of rupture by investigating degeneration of the aneurysmal wall and possible involvement of apoptosis. Immunohistochemistry with anti-actin antibody showed few smooth muscle cells in the ruptured aneurysms and replacement of the muscularis layer by a fibro-hyalin tissue. However, at least one layer of smooth muscle cells was clearly observed in the unruptured aneurysms. Thus, smooth muscle cells in the wall of the ruptured aneurysms were much more degenerated than those in the wall of unruptured aneurysms. In addition, unruptured aneurysms with an angiographically smooth wall showed well-layered positive staining for anti-smooth muscle actin antibody while those with irregular shapes rarely reacted. We found, for the first time, evidence of DNA fragmentation in the aneurysmal wall. Apoptotic bodies were detected by means of a terminal transferase (TdT)-mediated dUTP biotin nick end labelling technique (TUNEL) and an anti-single-stranded DNA antibody in 54% (7/13) of the ruptured aneurysms. In contrast, apoptotic bodies were found in only 7% (1/14) of the unruptured cases. These results suggest that apoptotic cell death might be involved in the rupture of aneurysms.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 805 (1996), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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