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  • Cell & Developmental Biology  (29)
  • Human  (8)
  • Liver  (8)
  • Photochemistry  (7)
  • Atomic, Molecular and Optical Physics  (6)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 261 (1968), S. 42-58 
    ISSN: 1432-1912
    Schlagwort(e): Liver ; Hyperplasia ; Hypertrophy ; Mitosis ; Degree of Ploidy ; Leber ; Hyperplasie ; Hypertrophie ; Mitosen ; Ploidiegrad
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Benutzung eines elektronischen Partikelzählgerätes erlaubt eine schnelle und exakte Bestimmung von Zahl und Ploidiegrad der in der Leber enthaltenen Zellkerne. Die Darstellung geeigneter Kernpräparationen wird beschrieben und die Brauchbarkeit der Methode durch Vergleich mit herkömmlichen Zählverfahren belegt. Mit Hilfe des Verfahrens wurden Kernzahl und Ploidiegrad in der Leber von Ratten verschiedenen Alters und von solchen Tieren bestimmt, die zuvor α-HCH und Phenobarbital erhalten hatten. Die beiden Substanzen führen zu einer Vermehrung der Zellkerne und des Anteils tetraploider Kerne. Ähnliche Veränderungen sind beim altersabhängigen Wachstum der Tiere zu beobachten. Unter dem Einfluß von α-HCH und Phenobarbital zeigt sich im histologischen Schnitt eine Steigerung der Mitose-Rate. Diese Befunde belegen, daß Fremdstoffe in der Leber nicht nur eine Hypertrophie, sondern auch eine Hyperplasie, also eine Vermehrung der Parenchymzellen auslösen können; α-HCH ist in dieser Hinsicht wirksamer als Phenobarbital. Die toxikologische Bedeutung dieser Veränderungen wird diskutiert.
    Notizen: Summary The use of an electronic particle-counting device permits the rapid and accurate determination of the number and the degree of “ploidy” of cell nuclei contained in liver. The preparation of a suitable suspension of liver cell nuclei is described and the reliability of the method is demonstrated by comparing it with counting techniques in current use. The method has been used to determine the number and the “ploidy” of cell nuclei in the liver of rats which had been given α-benzene hexachloride (α-BHC=α-HCH) or phenobarbital. Either substance produces an increase in both the total number of nuclei and in the percentage of tetraploid nuclei. There is a concomitant increase in the number of mitoses seen in histological sections. These findings show that foreign substances not only produce hypertrophy of the liver but also hyperplasia, i.e. an increase in the number of parenchymal cells. α-BHC is more potent in this respect than phenobarbital. The toxicological significance of these effects is discussed.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 261 (1968), S. 26-41 
    ISSN: 1432-1912
    Schlagwort(e): Liver ; Growth ; DNA ; Drugs ; Induction ; Leber ; Wachstum ; DNS ; körperfremde Stoffe ; Induktion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Verabreichung der drei körperfremden Stoffe α-HCH, Phenobarbital und CFT 1201, führt zu einer Vergrößerung der Leber bei Ratten. Zeitlicher Verlauf und Ausmaß dieser Gewichtszunahme wurden untersucht und ihre Ursachen studiert. Das relative Lebergewicht 7 Wochen alter weiblicher Ratten wird durch einmalige Gabe von α-HCH um 45%, durch mehrmalige Gaben um maximal 100% erhöht. Es steight nach wiederholter Verabreichung von Phenobarbital um 35%, von CFT 1201 um 14%. Die Organvergrößerungen sind nach Absetzen der Substanzen weitgehend reversibel. Das Ausmaß der Gewichtszunahme ist altersabhängig. α-HCH und Phenobarbital bewirken in der Leber eine Zunahme von Protein, Lipoid, Glykogen und Wasser in physiologischen Relationen; CFT 1201 verursacht eine Verfettung des Organs. α-HCH und Phenobarbital lösen keine histologisch nachweisbaren Zellschädigungen aus. Unter α-HCH und Phenobarbital ist eine Vermehrung der Leber-DNS nachweisbar; der Zuwachs an DNS ist prozentual jedoch geringer als der Zuwachs an Lebermasse. Beide Substanzen beschleunigen den Einbau von radioaktivem Thymidin in Leber-DNS — bei HCH-Verabreichung bis zum Zehnfachen der Kontrollwerte. Die Ergebnisse lassen darauf schließen, daß α-HCH und Phenobarbital in der Leber Wachstumsvorgänge auslösen, die mit einer Neu-Synthese von DNS einhergehen.
    Notizen: Summary The administration to rats of α-benzene hexachloride (α-BHC=α-HCH) or of phenobarbital, substances known to enhance the metabolism of drugs, or of CFT 1201 (β-diethylaminoethyl phenyldiallylacetate), an agent which inhibits drug metabolism, leads to an enlargement of the liver. In this study the time-course of the changes in liver weight has been followed and the factors underlying this process have been studied. In 7 weeks old female rats the relative weight of the liver increases after a single dose of α-BHC by 45%, and after repeated doses by up to 100%. After repeated doses of phenobarbital the maximum gain in weight is 35% and after CFT 1201 14%. The enlargement of the organ is largely reversible when the substances are withdrawn. The extent of the weight gain is dependent on age. α-BHC and phenobarbital produce an increase, in physiological proportions, in the liver content of protein, lipids, glycogen and water. They do not produce cell damage, as judged by light microscopy. In contrast, CFT 1201 causes fatty infiltration of the organ. Following the administration of α-BHC and of phenobarbital the DNA content of the liver rises. The rise is not proportional to the increase in liver size. Both α-BHC and phenobarbital accelerate the incorporation of labelled thymidine into liver DNA. After α-BHC the rate of incorporation is up to ten times that of controls. It is concluded from these results, that α-BHC and phenobarbital initiate growth processes in the liver which are accompanied by de novo synthesis of DNA.
    Materialart: Digitale Medien
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  • 3
    ISSN: 0167-0115
    Schlagwort(e): Angiotensin ; Arginine vasopressin ; Human ; Hymenoptera venom anaphylaxis ; Oxytocin ; Plasma concentration
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 193 (1996), S. 181-190 
    ISSN: 1432-0568
    Schlagwort(e): Testis ; Myoid cells ; Fetus ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Testicular peritubular cells are located in the lamina propria of seminiferous tubules. These cells, significantly contributing to the basal membrane of seminiferous epithelium, have been studied in a number of species. However, there is a lack of data on the development of the lamina propria in the human testis. The aim of our survey was to investigate the characteristics of the lamina propria and, in particular, peritubular cells in the fetal human testes by immunohistological and stereological methods. Therefore, testes (14–39 weeks of gestation, n=45) were dissected and fixed in a 4% buffered paraformaldehyde solution. Several pieces of each testis were embedded in paraffin and processed for immunohistochemical and stereological analysis. All investigated testes have shown sex cords in the process of development and differentiation. Morphologically, peritubular cells in the lamina propria can be divided into two types: fibroblast-like (FL) and myoid-like (ML) type (cells which much resemble mature myoid cells). By immunohistochemistry, both FL and ML cells are found to be strongly positive for the intermediate filament desmin, but negative for α-smooth actin. While FL cells intensively express Ki-67 demonstrating proliferative activity, ML cells are found to be negative. The basement membrane of sex cords as well as the blood vessels of the interstitium show strong positivity to collagen IV and laminin. Concerning the correlation between the appearance of the investigated antigens with the gestational age, all antigens have been expressed (in the manner described above) already in the 14th week of gestation. The stereological analysis of the number (Nv) and volume (Vv) of peritubular cells indicates a pulsatile development of these cells in the lamina propria of the human fetal testis. While the stereological variables determined for FL cells show a gradual decrease, the same variables determined for ML cells demonstrate a successive increase. It appears that the lamina propria of the fetal human testes shares many of the properties previously discovered in rodents.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1432-0533
    Schlagwort(e): Key words Allograft-inflammatory factor-1 ; Microglia response factor-1 ; Macrophage-inhibiting factor ; related-protein-8/S100A8 ; Traumatic brain injury ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Intracellular calcium (Ca2+) has been shown to function as second messenger and to be associated with activation of different cell types including microglia. Previously, in human focal cerebral infarctions an early expression of macrophage-related protein-8 (MRP8/ S100A8), a member of the Ca2+-binding S100-protein family, in microglia has been reported. On the other hand, a delayed activation of microglia was observed following traumatic brain injury (TBI). We therefore examined immunohistochemically microglial expression of MRP8 and allograft inflammatory factor-1 (AIF-1), identical to microglial response factor-1 (mrf-1) and ionized calcium binding adaptor molecule-1 (iba1) in human brains after TBI and in control brains. Both, MRP8 and AIF-1 are Ca2+-binding peptides which have been associated with microglial activation in experimental models and in human cerebral infarctions. Detection of AIF-1 in controls confirmed constitutive expression of this peptide in a subset of microglial cells. After TBI, the density of AIF-1+ microglia did not increase significantly. Lesional expression of AIF-1 did not significantly differ from other brain regions. Furthermore, following TBI, we found no significant differences in the density of AIF-1+ microglia as compared to controls. Microglial MRP8 expression was not detectable in controls and within the first 3 days post TBI, but increased rapidly after 3 days post TBI, suggesting a subpopulation of microglial cells to be AIF-1–/MRP8+. We conclude that the delayed expression of MRP8 and the lack of AIF-1 up-regulation in microglia after TBI is in contrast to ischemic brain lesions and might reflect different activation cascades of microglia.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    International archives of occupational and environmental health 44 (1979), S. 25-43 
    ISSN: 1432-1246
    Schlagwort(e): Electron microscopy ; Morphometry ; Freeze etching ; Liver ; Aging ; Polychlorinated biphenyls ; Elektronenmikroskopie ; Morphometrie ; Gefrierätzung ; Leber ; Altern ; polychlorierte Biphenyle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung In der vorliegenden Untersuchung wurden jungen und alten männlichen Wistarratten polychlorierte Biphenyle (PCB) i.p. appliziert. Die altersbedingten und die hepatotoxischen Veränderungen in der Leber wurden licht- und elektronenmikroskopisch erfaßt. Des weiteren wurden Membranveränderungen mit der Gefrierätzung nachgewiesen. Neben den altersbedingten Veränderungen im Vergleich der beiden Kontrollkollektive fällt vor allem die exzessive Proliferation des glatten endoplasmatischen Retikulums auf, welche nach PCB-Applikation in den Hepatocyten nachzuweisen ist. Bei den jungen Ratten betrug die Vermehrung der Oberflächen-dichte dieser Membranen im Vergleich zu den Kontrolltieren 803% (P〈0,001) und bei den alten Ratten 282% (P〈0,001). Bei alten anderen untersuchten Parametern wurden sowohl bei den jungen als auch bei den alten Ratten statistisch signifikante Verringerungen nach PCB-Gabe festgestellt.
    Notizen: Summary Thin-section and freeze-fracture techniques have been employed to investigate the ultrastructure of PCB-intoxicated rat liver of different ages. Besides alterations in the supramolecular structure of the plasma membranes, excessive proliferation of smooth endoplasmic reticulum (SER) in the hepatocytes was observed. In young rats, the surface density increased by up to 803% (P〈0.001) and in old rats up to 282% (P〈0.001) compared with the control rats. All other investigated parameters decreased significantly after the application of PCB.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    International archives of occupational and environmental health 48 (1981), S. 147-157 
    ISSN: 1432-1246
    Schlagwort(e): Diesel exhaust emission ; Liver ; Electron microscopy ; Freeze-fracture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The livers of Syrian golden hamsters were examined with the light and electron microscope using the techniques of thin sectioning and freeze-fracture following 5 months of exposure to various concentrations of diluted diesel exhaust gases. The light microscopical examination showed enlarged sinusoides with activated Kupffer's cells and slight changes in the cell nuclei. In the electron microscopical examination the most striking changes were seen in the mitochondria, which frequently showed a loss in cristae. In addition, the mitochondria exhibited pleomorphic character. The microbodies were of the same size as mitochondria. An increase in the number of lysosomes was observed especially in the tissue surrounding the narrow bile canaliculi. The various alterations corresponding to the different concentrations of exhaust gases could be seen especially well in the sinusoides, the mitochondria and the microbodies. In general the hepatocytes appeared to be moderately enlarged. The zonulae occludentes showed a more irregular outline and large maculae tight junctions were found on the lateral region of the plasmalemma of hepatocytes. The gap junctions exhibited a wide range of structural diversity. The intramembranous particles on the P fracture face of the plasmalemma of hepatocytes are aggregated.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    International archives of occupational and environmental health 49 (1982), S. 305-314 
    ISSN: 1432-1246
    Schlagwort(e): Polycyclic aromatic hydrocarbon ; Liver ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Female NMRI mice aged 9–12 weeks were each given a single subcutaneous injection of 0.5 ml of a suspension containing either the total extracts or the polycyclic aromatic hydrocarbon (PAH) fraction of airborne particles. Both the total extracts and PAH fractions contain 3 Vg benzopyrene. After about 15 months the livers were removed from the animals, which had by that time developed tumors at the injection site, and were subjected to ectronmicroscopical study. The essential alterations were observed in the nucleoli and the cell nuclei, which had greatly proliferated and exhibited irregular nuclear membranes. Advanced fibrosis was observed in central liver specimens of all groups. Marked alterations were also observed in the mitochondria and the mitochondria) cristae as well as in the bile canaliculi. Intracytoplasmic glycogen usually occurred densely clustered along the periphery of the cell. It may be concluded from the observations that both the total extract of atmospheric suspended particulate matter and the PAH fraction cause hematogenic damage to the liver following subcutaneous injection, a finding which cannot be interpreted as metastatic carcinoma.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-1106
    Schlagwort(e): Vestibuloocular reflex ; Velocity storage ; Active head tilt ; Semicircular canals ; Otolith ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Reorienting the head with respect to gravity during the postrotatory period alters the time course of postrotatory nystagmus (PRN), hastening its decline and thereby reducing the calculated vestibular time constant. One explanation for this phenomenon is that the head reorientation results in a corresponding reorientation of the axis of eye rotation with respect to head coordinates. This possibility was investigated in 10 human subjects whose eye movements were monitored with a three-dimensional magnetic field — search — coil technique using a variety of head reorientation paradigms in a randomized order during PRN following the termination of a 90°/s rotation about earth vertical. Average eye velocities were calculated over two time intervals: from 1 s to 2 s and from 7 s to 8 s after cessation of head rotation. The time constant was estimated as one third of the duration of PRN. For most conditions, a reorientation of the head with respect to gravity 2 s after the rotation had stopped did not significantly alter the direction of the eye velocity vector of PRN with respect to head coordinates. This strongly indicates that, in humans, PRN is mainly stabilized in head coordinates and not in space coordinates, even if the otolith input changes. This finding invalidates the notion that the shortening of PRN due to reorientation of the head could be due to a change of the eye velocity vector towards a direction (torsion), which is not detectable with the eye recording methods (electrooculography) used in earlier studies. The results regarding the vestibular time constant basically confirm earlier findings, showing a strong dependence on static head position, with the time constant being lowest if mainly the vertical canals are stimulated (60° nose up and 90° left ear down). In addition, the time constant was drastically shortened for tilts away from upright. The reduction in vestibular time constant with head reorientation cannot be explained solely on the basis of the dependence of the time constant on static head position. A clear example is provided by head reorientations back towards the upright position, which results in a decrease in the time constant, rather than an increase that would be expected on the basis of static head position.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-1106
    Schlagwort(e): Pavlovian conditioning ; Slow potentials ; Event-related potentials ; Gamma-band activity ; Skin conductance ; Motor conditioning ; Cholinergic modulation ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We examined slow potentials, transient event-related potentials, and oscillatory-like responses in the electroencephalogram during aversive conditioning in humans, in order to determine what is happening in the neocortex when behavioral adaptations are learned. Pictures of an angry and a happy human face served as rein-forced (CS+) and unreinforced (CS-) conditioned stimu li, respectively, in one group, and either the reversed condition or two discriminably different neutral faces in two other groups (total n=48 subjects). The unconditioned stimulus (US) was intracutaneous shock delivered to the left hand 5 s after CS+ onset. The electroencephalographic (EEG) activity was recorded from Fz, Cz, Pz, C3, and C4, electromyographic (EMG) activity from bilateral forearm and corrugator muscles, and skin conductance from the right hand. During acquisition a negative slow potential developed after CS+ (not CS-), which was more pronounced when a neutral face served as CS+. Early (iCNV, initial contingent negative variation) and late (tCNV, terminal contingent negative variation) components of the slow-potential response were positively related to the magnitude of conditioned EMG responses. Differentiation of tCNV was larger when neutral faces signaled the US; iCNV persisted during extinction when a happy face served as CS+. Late-occurring event-related potentials (ERPs) elicited by the US diminished over conditioning, whereas short-latency US components and ERPs elicited by CS events did not. Fourier analysis revealed oscillatory (“gamma-band”) activity between 30 and 40 Hz, which persisted up to 3 s after US delivery and diminished as conditioning progressed. Our findings indicate that learning is expressed in neocortical structures at the earliest stages of conditioning. The functional roles of the three types of EEG response in learning are discussed.
    Materialart: Digitale Medien
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