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  • 1
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Parkinson's disease is characterized by massive degeneration of the melanized dopaminergic neurons in the substantia nigra. The functional capacity of the surviving nigral neurons is affected, as indicated by the subnormal levels of tyrosine hydroxylase (TH) mRNA in these neurons and the presence in the parkinsonian mesencephalon of melanized neurons lacking TH immunoreactivity. This is apparently in contradiction with the known overactivity of dopamine synthesis and release that occurs in the remaining dopaminergic terminals. To test the ability of the surviving neurons to express TH protein, a semiquantitative immunocytochemical method was developed. The relative amounts of TH were estimated with a computer-assisted image analysis system in the dopaminergic neurons of representative mesencephalic sections of control and parkinsonian brains and for comparison in brains from patients with Alzheimer's disease. In control brains, the mean TH content per neuron differed from one subject to another and between the different dopaminergic cell groups of the mesencephalon in the same subject. Within a given dopaminergic region, the level of TH was variable among neurons. In patients with Parkinson's disease, the ratio of TH protein content per neuron in the substantia nigra by reference to that of the central gray substance was reduced. In patients with Alzheimer's disease, the amount of TH was selectively reduced in the remaining dopaminergic neurons of the ventral tegmental area, a region characterized by a loss in dopaminergic neurons. The decrease in cellular TH content might therefore be related to the presence of the neurodegenerative process in the area considered. In patients with Parkinson's disease, the incapacity of the surviving neurons to express normal TH levels may reduce the efficiency of the hyperactivity mechanisms that develop in the remaining striatal dopaminergic terminals.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The contribution of neuromelanin (NM) to the pathogenesis of Parkinson's disease (PD) has long been suspected. In particular, a correlation has been reported between the estimated cell loss in the mesencephalic dopaminergic cell groups and the percentage of NM-pigmented neurons in these cell groups. To test whether the amount of pigment per cell is a critical factor or whether the presence of NM within a neuron is sufficient to account for the degeneration of dopaminergic neurons, the NM content was measured in each neuron from representative sections throughout the ventral mesencephalon of four control subjects and four patients with PD. Intraneuronal NM was quantified by a densitometric method, using known amounts of synthetic melanin as standards. In control brains, the distribution of melanized neurons in the nigral complex showed a high proportion of lightly melanized neurons in the ventral tegmental area and the pars α and γ of the substantia nigra (SN), whereas heavily melanized neurons were mostly located in the pars β and lateralis of the SN. An inverse relationship was observed between the percentage of surviving neurons in PD compared with controls and the amount of NM they contain, suggesting that the vulnerability of the dopaminergic neurons is related to their NM content. Factors other than NM may be involved in the differential vulnerability of catecholaminergic neurons in PD. In particular, the constant topography of the cell loss suggests that cell position within the nigral complex is a key factor.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 60 (1993), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The molecular mechanisms underlying cell cycle control in neuronal progenitors have been investigated with adult mouse olfactory epithelium as a model system. Odorreceptive neurons of mammalian olfactory epithelium are short-lived and renewed in the adult by mitotic division of intrinsic neuronal progenitors. Ablation of the synaptic target, olfactory bulb, induces sequentially extensive apoptosis of sensory neurons and then stimulation of progenitor proliferation, peaking at 36 h and 4 days, respectively, postlesion. Known molecular effectors of G1 phase entry have been assessed on protein extracts of olfactory organs sampled at various postbulbectomy times in adult mice. The decay of βIII-tubulin and olfactory marker protein levels and the rise of proliferating cell nuclear antigen (PCNA) levels, starting 1 and 3 days, respectively, postlesion, provided the kinetic frame of neuronal dynamics. Cyclin D1, cyclin E, and cyclin-dependent kinase cdk2 levels, low in olfactory organ of intact mice, increased 3 days after bulbectomy in parallel with PCNA levels; cdk4 content was initially high and unaffected by lesioning. Western blots of the known cdk inhibitors revealed proliferation-related decreases of p18, p21, and p27 from high expression in intact organs. Immunoprecipitation of cdk2 and cdk4 fractions of protein extracts at 4 days postlesion (mitotic reaction peak) versus control, followed by cyclin D1 immunoblotting, and vice versa, revealed that levels of both cyclin D1/cdk2 and cyclin D1/cdk4 complexes, as well as their kinase activities, were dramatically increased after lesion. In vivo proliferation of olfactory neuronal lineage cells thus involves functional binding of cyclin D1 with cdk2 and cdk4, with differential activation mechanisms for cdk2 and cdk4. In addition, the RT-PCR-detected cyclin D1 mRNA level remained unaffected after bulbectomy, which indicated that the cyclin D1 rise should involve posttranscriptional mechanisms in this in vivo neuronal system. These observations are discussed, along with their relevance to cell cycle control and to olfactory neuron dynamics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Thin Solid Films 250 (1994), S. 101-110 
    ISSN: 0040-6090
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Zoomorphology 4 (1925), S. 711-738 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Zusammenfassung 1. Die Aviculariidae besitzen Gnathocoxen, die sick besonders durch folgende Eigentümlichkeiten vor den Gangbeinhüften auszeichnen: Ihre Unterseite ist nach vorn vorgezogen. Das Distalende des Vorderrandes der Unterseite endet in ein Zipfelchen. 2. Die Atypidae besitzen Gnathocoxen mit folgenden Merkmalen: Der distale Endzipfel ist zu einer machtigen Lade geworden. Die Unterseite ist nosh stärker verbreitert als bei den Aviculariidae. 3. Die Gnathocoxen aller Tetrapneumones liegen in einer Ebene mit den Laufbeinhüften, also horizontal. 4. Die Gnathocoxen der Dipneumones liegen stets mehr oder weniger vertikal, wie auch die Cheliceren. 5. Die Pedipalpenhüften der Dipneumones lassen sich folgendermaßen kennzeichnen: Die Ventralseite ist außerordentlich nach vorn distal verbreitert. Die Dorsalseite ist ganz schmal. Sie inserieren am Labrumsockel. Die Lade ist der der Atypidae and damit auch dem Endzipfel und der Unterseitenverbreiterung der Aviculariidae homolog. 6. Die Dysderidae besitzen Gnathocoxen, die noch deutlich den Hüftteil vom Ladenteil unterscheiden lassen. Auch ist bei ihnen noch die Coxalleiste in ihrer urspriinglichen Gestalt zu finden. 7. Die Dipneumones besitzen einen vertikalen präoralen Mundraum, der von beiden Laden and im proximalsten Teile der Ober- und der Unterlippe gebildet wird. 8. Die Skorpione haben einen horizontalliegenden Vormundraum. Er wird gebildet von den Unterseiten beider Pedipalpenhiiften, der Oberlippe und den Laden der beiden ersten Beinpaare. 9. Die Laden der ersten beiden Beinpaare vertreten die Unterlippe bei den Skorpionen. 10. Es ist unwahrscheinlich, daß der Besitz von Kauladen bei den Arachniden ein urspriingliches Merkmal ist, da man dann annehmen müßte, daß diese einst kauen konnten and diese Fähigkeit verloren hätten. 11. Die Mundbildung der Skorpione ist sehr kompliziert. Sie bedeutet den Endpunkt einer Entwicklung. 12. Die Mundbildung der Skorpione ist von allen lebenden Arachniden so gründlich verschieden, daß wir annehmen miissen, she sei isoliert von der Entwicklung der übrigen Gruppen innerhalb der Ordnung ausgebildet worden.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-1420
    Keywords: Key words Scoring systems ; APACHE II ; TISS ; length of hospital stay ; outcome research ; Schlüsselwörter Score-Systeme ; APACHE II ; TISS ; Hospitalliegezeit ; Ergebnisforschung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ziel der vorliegenden Untersuchung war es zu überprüfen, ob die Aussagekraft eines kombinierten physiologisch-therapeutischen Scoring-Systems (MARIS = Marburger Intensiv Score) der Aussagekraft eines rein physiologisch basierten Systems (APACHE II = Acute Physiology and Chronic Health Evaluation II) und der eines rein therapeutisch-interventionell basierten Systems (TISS = Therapeutic Intervention Scoring System) in der internistischen Intensivmedizin überlegen ist. Zielparameter waren Hospital-Letalität, Erkrankungs-Schweregradklassifikation und Hospital-Liegezeit. Hierzu wurde auf einer internistischen Intensivstation über 12 Monate 1993/94 bei 531 konsekutiven Patienten (Liegezeit 〉4 Stunden) eine prospektive Erhebung der Tag-1-Scores des MARIS, APACHE II und TISS durchgeführt. Hinsichtlich der gruppenbezogenen Diskriminationsfähigkeit zwischen Überleben und Versterben mit dem Bezugspunkt Krankenhausletalität (Flächen unter der ROC-Kurve: MARIS = 0,84, APACHE II = 0,86, TISS = 0,78) zeigte sich ebensowenig eine Überlegenheit des kombinierten Systems wie hinsichtlich der Erkrankungsschweregradklassifikation (Abhängigkeit der Letalität von der Scorewerthöhe; p〈0,001 im Chi2-Test für alle drei Systeme). Demgegenüber ergab sich hinsichtlich der Untersuchung der Abhängigkeit der Hospital-Liegezeit der Patienten von der Tag-1-Scorewerthöhe ausschließlich für den MARIS eine positive Beziehung sowohl bei isolierter Betrachtung nur der Überlebenden als auch bei Betrachtung aller Patienten (p〈0,001; einfaktorielle Varianzanalyse). Synoptisch ist zu folgern, daß der MARIS als kombiniertes physiologisch-therapeutisch basiertes Score-System für die gruppenbezogene Anwendung zur Diskrimination zwischen Überleben und Versterben und zur Erkrankungsschweregradklassifikation keine Vorteile gegenüber der Verwendung eines etablierten rein physiologisch (APACHE II) oder rein therapeutisch-interventionell (TISS) basierten Systems erbringt. Seine Anwendung kann hingegen möglicherweise ein erfolgversprechender Ansatz bei der Betrachtung von Zusammenhängen zwischen initialen Scorewerten und dem aus ökonomischen Gründen zunehmend wichtigen Zielparameter Hospital-Liegezeit sein.
    Notes: Summary The aim of the study was to evaluate if a combined physiologic-therapeutic scoring system (MARIS = Marburger Intensive Score) offers better outcome prediction compared to scoring systems, which are based either only physiologically (APACHE II = Acute Physiology and Chronic Health Evaluation II) or only therapeutically (TISS = Therapeutic Intervention Scoring System) in medical intensive care medicine. Main outcome parameters employed were hospital mortality, severity of disease classification and length of hospital stay. During a 12-months period (1993/94), 531 consecutive patients (ICU stay 〉4 hours) being admitted to a medical ICU of a tertiary care university hospital were prospectively investigated. The day-1-scores of MARIS, APACHE II, and TISS were determined and the patients were followed until hospital discharge or death. There was no advantage in using the combined scoring system (MARIS) neither in discrimination between survival and non-survival (hospital mortality; areas under the ROC-curve: MARIS = 0.84, APACHE II = 0.86, TISS = 0.78) nor in severity classification (relationship between day-1-scores and hospital mortality: p〈0.001 (chi2-Test) in all three systems). In contrast only for the combined system (MARIS), a dependence of length of hospital stay from day-1-scores in the analysis of survivors only and in the analysis of all patients (survivors and non-survivors) (p〈0.001; ANOVA) could be demonstrated. In conclusion the combined physiologic-therapeutic scoring system (MARIS) did not offer a better outcome prediction concerning hospital mortality and severity classification compared to the established systems in critically ill patients. Its use may be advantageous in evaluating the relationship between day-1-scores and length of hospital stay, which for economical reasons has become a parameter of growing interest in intensive care medicine.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Hyperfine interactions 42 (1988), S. 1145-1148 
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The use of He-filled proportional counters for CEMS studies with57Fe is very attractive because of their high efficiency. Stability problems at low temperature have been solved by using an electronic feed back which controls the anode voltage to keep the gas gain constant. Long term stable operation has been achieved between 370 K and 50 K. The potential of the counter is demonstrated on epitaxial and amorphous magnetic thin films.
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