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  • 1
    ISSN: 1432-0738
    Keywords: Fungal cyclic peptide ; Mycotoxin ; Cyclochlorotine ; Periportal liver necrosis ; Cytochrome p-450
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Sequential morphological changes in murine liver induced by cyclochlorotine (CC), a secondary metabolite of Pencicillium islandicum were investigated by transmission electron microscopy and scanning electron microscopy. Within 15 min after the administration of CC there was a marked dilatation of Disse's space around the portal triads, and the exudates then poured out into the space which was formed by the invagination of the hepatocyte plasma membrane. Shortly after the invagination was completed, the connection between Disse's space and the invaginated space was pinched off, so that this space became a membrane-bound vacuole. After dehydration, the vacuoles became granular. The liver injuries induced by CC were influenced by various pretreatments. The results indicate that drug-metabolizing systems mediated by cytochrome p-450 in the hepatocytes may play an important role in the hepatotoxicity of CC.
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  • 2
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Tatsache, daß die Leberzellen stärker durch Inkorporation von 3H-Aflatoxin markiert werden als die Mesenchymzellen entspricht der Beobachtung, daß Leberzellen gegenüber Aflatoxinen anfälliger sind als die Mesenchymzellen. Es zeigten sich keine signifikanten Unterschiede hinsichtlich der Inkorporation von 3H-Aflatoxin B 1, B 2 und 4HB 1 in die Leberzellen, während diese drei Mycotoxine eine weite Variation hinsichtlich ihrer Hemmwirkung auf die RNS-Synthese aufwiesen. Man kann also daraus den Schluß ziehen, daß die Toxizität von Aflatoxinen für Leberzellen in vitro eng zusammenhängt mit der Membrandurchlässigkeit und dem aktiven Teil des Aflatoxinmoleküls bzw. der Dop pelbindung in Difuranstruktur und der Carbonylgruppe in dem Cyclopentenon-Anteil von B 1.
    Notes: Summary The distribution patterns of 3H-aflatoxin B 1, B 2 and tetrahydrodesoxoaflatoxin B 1 (4H B 1) in the cultured liver cells originated from the 12-day-old chicken embryo were demonstrated. The fact that the hepatocytes were more heavily labeled than the mesenchymal cells by the incorporation of 3H-aflatoxins correlate well with the observation that the hepatocytes were more susceptible than the mesenchymal cells to the aflatoxins. There were no significant differences in the pattern of incorporation of 3H-aflatoxin B 1, B 2 and 4H B 1 into the hepatocyte, while the three mycotoxins show a wide variation in their inhibitory action in RNA synthesis. It may be concluded from the above mentioned facts that the toxicity of aflatoxins to the liver cells in vitro is closely related to the membrane permeability and the active portion of the molecule of aflatoxins, such as the double bond in the difuran structure and the carbonyl group in the cyclopentenone portion of B 1.
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  • 3
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Nucleolen von Leberzellen der Ratte erleiden nach Gaben von 8 verschiedenen Nitrosoverbindungen und 5 entsprechenden Nicht-Nitrosoverbindungen eine Vielfalt von spezifischen und unspezifischen Veränderungen. Nach oraler Zufuhr von Dimethylnitrosamin und Diäthylnitrosamin wurde eine ungewöhnliche Segregation der Nukleolen in den Zellen mit Karyorrhexis beobachtet. Sehr kennzeichnend für diese Segregation sind verstreute Ribosomen-artige Granula in der äußersten Schicht der veränderten Nucleolen. Oft sind Mikrosphären mit Halos 150 nm in allen Ratten zu finden, die mit Nitrosoverbindungen behandelt wurden, welche als carcinogen für andere Organe als die Leber beschrieben wurden. Mit Ausnahme von Butylharnstoff und Butylamin wurden keine solche spezifischen Mikrosphären in den Nucleoli nach der Verabreichung der korrespondierenden Nicht-Nitrosoverbindungen beobachtet.
    Notes: Summary The hepatocyte nucleoli of rats undergo a variety of specific and nonspecific alterations after the administration of 8 nitroso compounds and 5 corresponding non-nitroso compounds. After the oral administration of dimethylnitrosamine and diethylnitrosamine, an unusual segregation of the nucleolus was encountered in the cells with karyorrhexis. Most characteristic of the segregation are the scattered ribosome-like granules at the outermost layer of the altered nucleolus. Frequently microspherules with halos 150 nm in diameter are found in all rats treated with nitroso compounds, which have been reported to be carcinogenic in the organs other than the liver. With the exception of butylurea and butylamine no such specific microspherules were found in the nucleoli after the administration of coresponding non-nitroso compounds.
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  • 4
    ISSN: 1573-0832
    Keywords: Emestrin ; mycotoxin ; mycotoxicosis ; Emericella striata ; mouse liver ; mouse lymphoid tissue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The effects of emestrin (EMS), a secondary metabolite of the Emericella species, on male ICR mice were examined. The intraperitoneal LD50 values of EMS were 17.7 and 13.0 mg/kg at 24 and 48 hr, respectively. The target organs of EMS were the heart, liver and thymus. In doses over 30 mg/kg the experimental animals died from cardiac failure shortly after the injections. Several survivors that were given EMS in doses under 20 mg/kg showed severe centrilobular necrosis in the liver at 24 hr. Marked degeneration of mitochondria was seen in electron micrographs of both cardiac muscle cells and hepatocytes. In the degenerated hepatocytes, prominent proliferation of RER, membrane-limited inclusions containing both ribosome-like granules and RER, and fenestrated lamella-like structures were observed. Massive necrosis of lymphocytes was always observed in the cortical layer of the thymus of the survivors within 24 hr, while bilateral adrenalectomized mice showed no discernible pathomorphological changes in the lymphoid tissues. Pretreatment of mice with diethyl maleate increased the incidence and severity of hepatic necrosis, whereas that with either cysteine or CoCl2 reduced the severity of centrilobular necrosis of the liver. Pretreatment with phenobarbital had no significant effect on EMS-induced hepatic lesions.
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  • 5
    ISSN: 1573-0832
    Keywords: Nocardia otitidiscaviarum ; exotoxin poisoning ; RER ; autophagic vacuole ; nocardiosis ; fatty liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract An exotoxin (HS-6) produced by Nocardia otitidiscaviarum isolated from certain lesions of cutaneous nocardiosis of a male 82-year-old patient induced severe injuries in the pancreas, liver, stomach, small intestine, heart, thymus and kidney of male ICR mice. Mice given Nocardia-free preparation of HS-6 at a dose of 1 mg/kg of body weight developed several autophagic vacuoles in the pancreas and liver within 20 min after the i.p. injection. Thereafter, the autophagic vacuoles increased in number and size with time. About 24 hr after the administration of HS-6, the liver showed marked accumulation of fat droplets in the cytoplasm of the hepatocytes. Although they contained abundant autophagic vacuoles in the regions of RER, there were no lipomatoses in the acinar cells of the pancreas, those of the chief cells and smooth muscle cells of the stomach, Paneth cells, goblet cells, smooth muscle cells of the small intestine, and plasma cells in the digestive tract. Biochemical examinations revealed that HS-6 had no significant effect on the protein synthesis of reticulocytes. Inoculation of the Nocardia into the mouse peritoneal cavities caused marked granulomatoses in the pancreas, liver and regional lymph nodes, but did not develop autophagic vacuoles in RER regions of these organs.
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  • 6
    ISSN: 1573-0832
    Keywords: Nocardia otitidiscaviarum ; cutaneous nocardiosis ; toxic substance ; chemical structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract During our studies on toxic substances from clinically isolated Nocarida, a new isolate identified as Nocardia otitidiscaviarum from cutaneous nocardiosis was found to produce a toxic substance called HS-6 that had strong in vitro as well as in vivo toxicity. The mouse intraperitoneal LD50 value was 1.25 mg/kg and the ED50 value for L1210 cultured cells was 0.3 ng/ml. The structure of HS-6 was determined and found to belong to the 16-membered macrocyclic group with a molecular formula of C43H68O12. HS-6 also showed activity against pathogenic fungi such as Cryptococcus neoformans.
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  • 7
    ISSN: 1573-0832
    Keywords: Human PMN ; H. capsulatum ; fungicidal resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The basis for resistance of yeast form of Histoplasma capsulatum to antifungal activity of human neutrophils was studied. In limiting dilution assays and short term coculture assays human neutrophils were ineffective in killing H. capsulatum whereas Candida albicans was readily killed. By contrast, in a cell free hydrogen peroxide-peroxidase-halide system H. capsulatum was as sensitive to killing as C. albicans. Moreover, lysate of human neutrophils effectively substituted for horse-radish peroxidase in a cell free system for killing H. capsulatum. H. capsulatum elicited significant products of the oxidative burst in human neutrophils as detected by luminol-enhanced chemiluminescence. However, the response was two-fold less (p〈0.05) than that induced by C. albicans. Transmission electron microscopy studies showed that phagosome-lysosome fusion took place when neutrophils phagocytosed C. albicans or H. capsulatum. Taken together, these findings indicate that, even though H. capsulatum elicits an oxidative burst and phagosome-lysosome fusion within the phagosome, it is capable of evading damage in short term assays.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 137 (1973), S. 167-175 
    ISSN: 1432-0878
    Keywords: Leydig cells ; Mouse ; Ring-shaped nucleolus ; Endoplasmic reticulum ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Many mature Leydig cells of adult mice contain annular nucleoli. In the cytoplasm of these cells, there is an abundance of agranular endoplasmic reticulum and its modifications, i.e. membranous whorls and double-walled tubules. By contrast, the cytoplasm of Leydig cells with compact nucleoli shows abundant free ribosomes and granular endoplasmic reticulum. It is assumed that the granular endoplasmic reticulum shifts to the agranular endoplasmic reticulum and its modifications during the differentiation of the Leydig cell. For the maturation of the Leydig cell the annular nucleoli may play an important role.
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