Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Nigrostriatal and mesolimbic dopaminergic activities were modified throughout the ovarian cycle of female rats (1991)
    Springer
    Journal of neural transmission 85 (1991), S. 223-229 
    Details
    ISSN: 1435-1463
    Keywords: Sexual steroids ; estrous cycle ; limbic forebrain ; striatum ; dopamine ; DOPAC ; tyrosine hydroxylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this work, we have studied the changes in the functional state of nigrostriatal (NSDA) and mesolimbic (MLDA) dopaminergic neurons during the estrous cycle of the female rat. The activity of tyrosine hydroxylase (TH), the turnover rate (Kt) after inhibition of dopamine (DA) synthesis and the ratio between the contents of this amine and its metabolite, L-3,4 dihydroxyphenylacetic acid (DOPAC), were used as indices of neuronal activity. The neuronal activity of NSDA neurons rose during estrous and declined during proestrous, as reflected by the values of Kt and DOPAC/DA ratio measured during both phases. Interestingly, the course of variations in striatal TH activity was similar, although retarded in relation to the changes in neuronal activity. Thus, TH activity was high during diestrous, whereas it was low during estrous. The activity of MLDA neurons was reduced during proestrous. This can be concluded from the decreased Kt and DOPAC/DA ratio measured in this phase and it was accompanied by a low TH activity. Thereupon, both Kt and TH activity increased during estrous. These results indicate the existence of physiological changes in the functional state of both dopaminergic systems during the ovarian cycle, which are partially different for each neuronal pathway. This supports the existence of a specific regulation, and not indiscriminate effects, by the hormones involved in this cycle, mainly estradiol and progesterone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244947
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Detection of coronary artery disease in diabetic patients (1995)
    Springer
    Diabetologia 38 (1995), S. 726-731 
    Details
    ISSN: 1432-0428
    Keywords: Key words Non-invasive test ; detection ; coronary artery disease ; diabetic patients.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Coronary artery disease may be difficult to detect in diabetic patients. This study was designed to determine the specificity and sensitivity of three non-invasive tests. Accordingly, the results of 48-h ambulatory electrocardiogram (ECG) monitoring, maximal ECG exercise test, and intravenous dipyridamole myocardial thallium scintigraphy were compared in 59 middle-aged diabetic patients who were consecutively selected for suspected coronary artery disease. All patients also underwent coronary angiography, which was performed regardless of the results of the non-invasive tests. Twenty patients (34 %) had significant coronary lesions, i. e. stenosis equal to or greater than 70 %, and 16 of these 20 patients (80 %) had double or triple vessel disease. Sensitivity and specificity were, respectively, 25 % and 88 % for ambulatory ECG monitoring, 75 % and 77 % for the exercise test and 80 % and 87 % for thallium myocardial scintigraphy. This observation strongly supports the use of non-invasive tests for the detection of coronary artery disease in those diabetic patients at high risk of such disease. As the exercise test is cheaper and more widely available than thallium myocardial scintigraphy it should be used as a first line examination. Dipyridamole myocardial scintigraphy may provide an alternative solution for those patients who cannot perform maximal exercise, or with atypical clinical presentation. [Diabetologia (1995) 38: 726–731]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401847
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Detection of coronary artery disease in diabetic patients (1995)
    Springer
    Diabetologia 38 (1995), S. 726-731 
    Details
    ISSN: 1432-0428
    Keywords: Non-invasive test ; detection ; coronary artery disease ; diabetic patients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Coronary artery disease may be difficult to detect in diabetic patients. This study was designed to determine the specificity and sensitivity of three non-invasive tests. Accordingly, the results of 48-h ambulatory electrocardiogram (ECG) monitoring, maximal ECG exercise test, and intravenous dipyridamole myocardial thallium scintigraphy were compared in 59 middle-aged diabetic patients who were consecutively selected for suspected coronary artery disease. All patients also underwent coronary angiography, which was performed regardless of the results of the non-invasive tests. Twenty patients (34%) had significant coronary lesions, i.e. stenosis equal to or greater than 70%, and 16 of these 20 patients (80%) had double or triple vessel disease. Sensitivity and specificity were, respectively, 25% and 88% for ambulatory ECG monitoring, 75% and 77% for the exercise test and 80% and 87% for thallium myocardial scintigraphy. This observation strongly supports the use of non-invasive tests for the detection of coronary artery disease in those diabetic patients at high risk of such disease. As the exercise test is cheaper and more widely available than thallium myocardial scintigraphy it should be used as a first line examination. Dipyridamole myocardial scintigraphy may provide an alternative solution for those patients who cannot perform maximal exercise, or with atypical clinical presentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401847
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Modifications of mesolimbic and nigrostriatal dopaminergic activities after intracerebroventricular administration of prolactin (1994)
    Springer
    Journal of neural transmission 96 (1994), S. 63-79 
    Details
    ISSN: 1435-1463
    Keywords: Prolactin ; striatum ; limbic forebrain ; dopamine ; DOPAC ; tyrosine hydroxylase ; D1 and D2 receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present study we examined the effects of intracerebroventricular (i.c.v.) injections of prolactin (PRL) on the presynaptic activity and postsynaptic sensitivity of mesolimbic and nigrostriatal dopaminergic neurons. In addition, the effects of PRL onin vitro release of dopamine (DA) from perifused striatal fragments were examined. Tyrosine hydroxylase (TH) activity and D2 receptor density in the striatum decreased after i.c.v. PRL administration; this was accompanied by an increase in D2 receptor affinity. These effects occurred after i.c.v. administration of PRL to normoprolactinemic rats, although normally they did not appear after administration to animals with pituitary grafting-induced hyperprolactinemia. Thus, in these animals, i.c.v. PRL failed to decrease TH activity and D1 and D2 receptor densities to a significant extent. In the case of D2 receptors, this was probably due to the fact that pituitary grafting-induced hyperprolactinemia itself was able to reduce the density of this receptor. No changes were observed in DA or L-3, 4-dihydroxyphenylacetic acid (DO-PAC) contents after i.c.v. administration of PRL to both normo- and hyperprolactinemic animals. Basal and K+-evoked DA releasein vitro from perifused striatal fragments of normoprolactinemic rats were not affected by the addition of PRL, whereas this hormone enhanced K+-evoked DA release when added to perifused striatal fragments from hyperprolactinemic animals. In the limbic forebrain, i.c.v. administration of PRL to normoprolactinemic animals produced a decrease in DA and DOPAC contents and D1 receptor density. Interestingly, none of these effects appeared when PRL was injected to hyperprolactinemic animals. In summary, our results suggest a possible inhibitory role of PRL on the activity of both the nigrostriatal and mesolimbic dopaminergic neuronal systems. These inhibitory effects were reflected in the decreases elicited in a set of neurochemical parameters, indicating either presynaptic activity or postsynaptic sensitivity, after i.c.v.-administered PRL. This observation supports the hypothesis of a possible neuromodulatory role for an extrapituitary PRL on the activity of these neurons, although the fact that most of these effects did not appear when i.c.v. administration was performed in hyperprolactinemic rats also suggests that they are influenced by peripheral PRL levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01277929
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    δ9-Tetrahydrocannabinol affects mesolimbic dopaminergic activity in the female rat brain: interactions with estrogens (1993)
    Springer
    Journal of neural transmission 92 (1993), S. 81-95 
    Details
    ISSN: 1435-1463
    Keywords: δ9-Tetrahydrocannabinol ; mesolimbic dopaminergic neurons ; estrogens ; dopamine ; dopaminergic receptors ; limbic forebrain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this work, we studied the possible estrogenic modulation of the effects of δ9-tetrahydrocannabinol (THC) on mesolimbic dopaminergic activity, by examining the effects of an acute dose of this cannabinoid: (i) during the estrous cycle; (ii) after ovariectomy, chronic estrogen-replacement and tamoxifen (TMX)-induced blockade of estrogenic receptors; and (iii) combined with a single and physiological injection of estradiol to ovariectomized rats. THC significantly decreased the density of D1 dopaminergic receptors and non-significantly increased the L-3,4-dihydroxyphenylacetic acid (DOPAC) content in the limbic forebrain of ovariectomized rats chronically replaced with estrogens. The decrease in D1 receptors was also produced by TMX, whereas the coadministration of both THC and TMX did not lead to a major decrease. In addition to the trend of THC increasing DOPAC content, this cannabinoid was also able to increase the ratio between DOPAC and dopamine, although this last effect only occurred after coadministration of THC and TMX, which had been ineffective administered individually. All these effects were not seen when THC was administered to normal cycling rats during each phase of estrous cycle and to ovariectomized rats without chronic estrogen replacement or only submitted to a single and acute dose of estradiol. This observation might be related to the fact that the density of limbic cannabinoid receptors increased in chronic estrogen-replaced ovariectomized ratsversus normal cycling, ovariectomized or acutely estrogen-treated ovariectomized rats. Interestingly, THC administration in ovariectomized rats was followed by a slight, although significant, increase in tyrosine hydroxylase activity, which was also observed after coadministration of THC with a short-time and acute dose of estradiol. In summary, THC stimulated the presynaptic activity of mesolimbic dopaminergic neurons, but accompanied by a decrease in their postsynaptic sensitivity. These effects did not appear in normal cycling rats being only evident after ovariectomy and chronic estrogen replacement, which might be related to changes in binding characteristics of cannabinoid receptors in this area. Moreover, some of them appeared after TMX-induced blockade of estrogenic cytosolic receptors, which likely suggests the existence of a certain estrogenic modulation of the actions of THC on mesolimbic neurons. On the contrary, coadministration of THC with a single and shortly tested dose of estradiol was always ineffective in modifying THC effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244868
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The repassivation capacity of Stainless steel-ceramic prostheses (1988)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 39 (1988), S. 364-369 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Repassivierungsfähigkeit von keramikbeschichteten EdelstahlprothesenDas Durchbruchs- und das Repassivierungspotential von keramikbeschichteten Prothesen aus nicht rostendem Stahl sind in Hanks-Lösung und an Implantaten an Hunden bestimmt worden. Diese Werkstoffe zeigen geringe Lochkorrosionsempfindlichkeit und starke Repassivierungsfähigkeit. Der Einfluß von Oberflächenrauhigkeit, Tauchzeit und der Homogenisierungsbehandlung auf das Lochfraßverhalten wird diskutiert.
    Notes: The breakdown and repassivation potentials of stainless steel-ceramic prostheses have been determined both in a Hanks' solution and in implants in dogs. These materials show low susceptibility to pitting corrosion as well as a high repassivation capability. The influence of surface roughness, exposure time and homogenization treatment on the pitting corrosion behaviour is studied.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19880390803
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Reliability of electrochemical methods applied to the study of Alumina coated stainless steel prosthesis (1986)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 37 (1986), S. 451-456 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zuverlässigkeit elektrochemischer Methoden bei der Untersuchung von Prothesen aus nichtrostendem Stahl mit AluminiumoxidüberzugIm vorliegenden Bericht wird die Korrosionsbeständigkeit von Prothesen aus nichtrostendem Stahl mit Aluminiumoxidüberzug erörtert; als Versuchsmaterial dienten Stahl AISI 316 L mit plasmagespritztem Aluminiumoxidüberzug (mit und ohne Nickel als Zwischenschicht).Die Nickelschicht soll die Haftung zwischen dem keramischen Material und dem Stahl gewährleisten. Als Prüfmedium diente die Hank'sche Lösung, da diese Ähnlichkeit mit organischen Flüssigkeiten aufweist. Zur Verbesserung der Aussagefähigkeit der Ergebnisse wird empfohlen, mehrere der nachstehenden elektrochemischen Methoden nebeneinander zu verwenden: Bestimmung der Zeitabhängigkeit des Korrosionspotentials; Polarisationswiderstandsmessung; coulostatische Methoden und Wechselstrommethoden. Bei der elektrochemischen Untersuchung von keramikbeschichtetem nichtrostendem Stahl im passiven Zustand ergeben sich einige spezifische Schwierigkeiten durch die Störung der Arbeitselektrode infolge der einwirkenden elektrischen Signale, wodurch die Genauigkeit der Korrosionsgeschwindigkeitsmessung beeinträchtigt wird. Diese Schwierigkeiten treten nicht auf, wenn eine Kombination mit einer aktiveren Zwischenschicht benutzt wird.
    Notes: The corrosion resistance of alumina-covered stainless steel prosthesis is discussed in this report. The test material was an AISI 316L steel with a plasma sprayed on alumina coating, applied directly or through an intermediate nickel base layer, whose mission is to guarantee a perfect adherence between the ceramic material and the steel. Use was made in the laboratory of Hank's solution as test medium since this solution is similar to organic fluids. In order to increase the reliability of the results the simultaneous use of various of the following electrochemical methods are recommended: Determination of corrosion potential with the time, polarization resistance method, coulostatic method and a.c. methods. The use of electrochemical methods to study ceramic-covered stainless steel in the passive state poses some specific difficulties accruing from the disturbance of the working electrode by the applied electrical signals which limit the accuracy of the corrosion rate measurements. These difficulties do not appear in the case of a material having a intermediate layer which is more active.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19860370805
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Environmental factors responsible for the unusual corrosion of galvanized steel (1989)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 40 (1989), S. 668-673 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Umweltfaktoren als Ursache der ungewöhnlichen Korrosion von verzinktem StahlEine ungewöhnlich starke Korrosion von feuerverzinktem Stahl in einer subtropischen Meeresatmosphäre wurde untersucht. Aufgrund der mittels Röntgenbeugungsanalyse der Korrosionsprodukte, des umgebenden Bodens und des aus der Luft abgelagerten Staubs sowie aufgrund der REM-Befunde und der EDAX-Analyse der losen Deckschicht sowie aufgrund der metallographischen Untersuchung von Schnitten durch verzinkten Stahl mit unterschiedlichem Korrosionsgrad wird ein Mechanismus für den Angriff vorgeschlagen, der die außerordentlich hohe Korrosionsgeschwindigkeit des verzinkten Stahls auf die dort herrschenden speziellen atmosphärischen Verhältnisse zurückführt.
    Notes: A phenomenon of unusual heavy corrosion of hot dip galvanized structural steelwork in a subtropical severe marine atmosphere has been studied. Through the data optained from X-ray diffraction analysis of corrosion products, surrounding soil samples and environmental dust samples, and from SEM observations and EDAX analysis of loose corrosion scale, as well as from the information provided by the metallographic study of galvanized steel sections with different degree of corrosion, a mechanism of attack has been proposed, which accounts for the special environmental factors prevailing on the place.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19890401107
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Comparative study of the corrosion behavior of MA-956 and conventional metallic biomaterials (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 31 (1996), S. 313-317 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In this work the corrosion behavior of a new biomaterial, the MA-956 superalloy, immersed in Hank's solution is evaluated. A comparison with conventional metallic alloys used as articular implants is established. To determine the corrosion behavior we employed electrochemical methods: evaluation of corrosion potential Ecorr, electrochemical impedance spectroscopy (EIS), and anodic polarization curves. The corrosion resistance of the MA-956 superalloy preoxidized at 1100°C during 100 h is at least two orders of magnitude higher than for the other alloys. This satisfactory behavior is stationary with time. Also the probability of the appearance of the pitting corrosion process is very low. When cracking is generated in the α-alumina layer the repassivation process is assured because of the high Cr content in the superalloy. This study is the first step in proposing this new alloy as a biomaterial. The low toxicity of these metallic alloys in the physiological environment suggests that in vivo their biocompatibility could be satisfactory. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 10
    Electronic Resource
    Electronic Resource
    Sulphur-33 nuclear magnetic resonance studies of sulphur compounds with sharp resonance lines. 33S NMR spectra of some sulphones and sulphonic acids (1981)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 15 (1981), S. 401-403 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 33S NMR spectra have been obtained in the FT mode for some sulphones and sulphonic acids. The investigated compounds show narrow resonance lines. In the case of sulphones, the range of 33S chemical shifts is sufficiently wide, i.e. the effects due to changes in substituents are significant enough to allow further use of the 33S NMR of sulphones for quantitative analysis in petroleum chemistry.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270150416
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...