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  • 1995-1999  (35)
  • 1990-1994  (30)
  • 1970-1974  (2)
  • 1960-1964  (2)
  • 31
    ISSN: 1437-1596
    Keywords: Nicotine ; Cotinine ; Gas chromatography/mass spectrometry ; Human Tissue ; Distribution ; Smokers' level ; Nikotin ; Cotinin ; Gaschromatographie/Massenspektrometrie ; Menschliches Gewebe ; Verteilung ; Tabakraucher
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Zur gleichzeitigen Bestimmung von Nikotin und Cotinin in verschiedenen Körpergeweben wurde eine zuverlässige und sensitive Methode mittels der Kapillar-Gas-Chromatographie/Massenspektrometrie entwickelt. Nikotin und Cotinin wurden durch einen 3-stufigen Extraktionsvorgang mit Chinolin als internem Standard isoliert und die Quantifizierung mittels der single ion monitoring-Technik durchgeführt, wobei für Nikotin das Ion m/z 133, für Cotinin m/z 176 und für Chinolin m/z 129 verwendet wurde. Die Detektionsgrenze lag in allen Geweben für Nikotin bei 5 ng/g und für Cotinin bei 10 ng/g, die Kalibrierung erbrachte lineare Verhältnisse im Bereich von 5–1.200 ng/g für Nikotin und im Bereich von 10–1.500 ng/g für Cotinin. Die Genauigkeit und Präzision der Methode wurde an verschiedenen Körpergeweben ausreichend bewiesen. Die Verteilung der beiden Verbindungen in verschiedenen Geweben wurde in 10 Fällen bestimmt. Die festgestellten Nikotinspiegel lagen hierbei bei Konzentrationen, die bei üblichen Tabakrauchern gemessen werden. Hohe Nikotinspiegel wurden in Leber, Niere, Milz und Lunge, niedrige Konzentrationen im Fettgewebe festgestellt. Die Cotinin-Konzentration lag in der Leber am höchsten. Das Gewebe-Blut-Verteilungsverhältnis für Nikotin und Cotinin war im Skelettmuskelgewebe am konstantesten, wobei die Konzentrationen hier jeweils nahe an den Konzentrationen im Blut lagen. Der Skelettmuskel ist somit das geeignetste Gewebe für toxikologische Untersuchungen, wenn die Asservierung von Blut nicht möglich ist.
    Notes: Summary A reliable and sensitive method for the simultaneous determination of nicotine and cotinine concentrations in various human tissues was developed using capillary gas chromatography/mass spectrometry. Nicotine and cotinine were extracted using a 3-step solvent extraction procedure and quinoline as an internal standard. Quantification was carried out by single ion monitoring using ions of m/z 133 for nicotine, m/z 176 for cotinine and m/z 129 for quinoline. The lower limit of detection was 5 ng/g for nicotine and 10 ng/g for cotinine, in each tissue sample. The calibration curves of various tissues were linear in the concentration range from 5–1,200 ng/g for nicotine and 10–1,500 ng/g for cotinine. The accuracy and precision of this method were examined using human tissues and the results were satisfactory. The distribution of nicotine and cotinine was measured in tissues from 10 human autopsies. Nicotine was detected in every tissue examined at a level seen in habitual smokers. The nicotine concentration was high in the liver, kidney, spleen and lung, and low in adipose tissue. The cotinine level was highest in the liver. The tissue/blood concentration ratios of nicotine and cotinine were most stable in skeletal muscle, where the level of these drugs was close to that in whole blood. Skeletal muscle is, therefore, considered to be the most suitable tissue sample for toxicological examination, when acquisition of blood samples is not feasible.
    Type of Medium: Electronic Resource
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  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 355 (1997), S. 412-416 
    ISSN: 1432-1912
    Keywords: Key wordsα1-adrenoceptor subtypes ; Urethra ; Cloned receptor ; NS-49 ; Binding assay ; Correlation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To identify the α1-adrenoceptor subtypes in the human prostatic urethra, we compared the potencies of various α1-adrenoceptor agonists and antagonists in inhibiting [3H]tamsulosin binding to human prostatic urethral membranes with their potencies in inhibiting the binding of (+)-β-([125I]iodo-4-hydroxyphenyl)ethylaminomethyl-tetralone ([125I]HEAT) to cloned human α1a, α1b and α1d subtypes. The α1A-selective antagonists 5-methylurapidil and (+)niguldipine showed higher affinities for both cloned α1a and urethral α1-adrenoceptors than for cloned α1b- and α1d-adrenoceptors. NS-49, (R)-3′-(2-amino-1-hydroxyethyl)-4′-fluoromethanesulfonanilide hydrochloride, recently characterized as an α1A-selective agonist, also showed high affinity for the cloned α1a subtype and urethral α1-adrenoceptors. Prazosin showed lower affinity for α1-adrenoceptors in the human prostatic urethra than for any of the three cloned α1-adrenoceptors. Comparison of the affinities of α1-adrenoceptor agonists and antagonists for human prostatic urethral α1-adrenoceptors to their affinities for the three cloned α1 subtypes indicated a close correlation between the affinities for human urethral α1 and the cloned α1a-adrenoceptors. However, prazosin did not conform to this pattern. These findings suggest that the predominant α1-adrenoceptor in the human urethra is the α1A subtype, and that an α1L subtype which has been characterised by its low affinity for prazosin, may also be present.
    Type of Medium: Electronic Resource
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  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 52 (1994), S. 196-202 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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  • 34
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 150-151 (Jan. 1994), p. 297-306 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 35
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 171-174 (Oct. 1999), p. 461-468 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 36
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 37
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 171-174 (Oct. 1999), p. 483-490 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 38
    Electronic Resource
    Electronic Resource
    Springer
    International journal of legal medicine 106 (1994), S. 288-290 
    ISSN: 1437-1596
    Keywords: Toxicology ; Polysulphides ; Sulphide ; Tissue samples-GC ; GC/MS ; Poisoning ; Toxikologie ; Polysulfid ; Sulfid ; Gewebe ; Gewebeproben ; GC ; GC/MS ; Vergiftung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Wir haben Tierexperimente durchgeführt, um bei Untersuchung von Gewebsproben toxikologisch eine Polysulfid-Vergiftung zu verifizieren. Ein Bade-Agens, welches Calcium-Polysulfid enthielt, wurde Ratten oral zugeführt. Hierauf wurden Polysulfide und Sulfid, das Abbauprodukt von Polysulfiden, mit Hilfe von GC and GC/MS untersucht. Die Konzentrationen der Polysulfide (μmol/ml oder g) wurden am höchsten im Blut gefunden (0,194), gefolgt von der Leber (0,051), den Lungen (0,018) und den Nieren (0,013). Die Konzentrationen waren in den übrigen getesteten Organen unterhalb der Nachweisgrenze (0,004 μmol/g). Sulfid wurde in allen Gewebsproben gefunden. Mit 0,518 μmol/ml war die Konzentration am höchsten im Blut. Diese Konzentration war 40 mal höher als jene, welche für tödliche Vergiftungen im Falle von H2S-Vergiftung erforderlich ist. Polysulfid-Vergiftungen wurden bestätigend diagnostiziert durch den Nachweis und die Messung von Polysulfiden und in Ergänzung Sulfid in Körpergeweben, am ausgeprägtesten im Blut. Zwei praktische Fallberichte von vermuteter Vergiftung mit Polysulfiden werden kurz beschrieben.
    Notes: Summary We carried out animal experiments to toxicologically verify polysulphide poisoning by analyzing tissue samples. A bathing agent containing calcium polysulphides was administered orally to rats, and then polysulphides and sulphide, the decomposed product of polysulphides, were analyzed by GC and GC/MS. The concentrations of polysulphides (μmol/ml or g) were found to be highest in blood (0.196), followed by the liver (0.051), the lungs (0.018) and kindneys (0.013), but were below the detection limit (0.005 μmol/g) in the other tissues tested. Sulphide was detected in all the tissue samples and was found to be highest in the blood (0.518 μmol/ml), this being 40 times higher than that required for fatal poisoning in the case of hydrogen sulphide. Polysulphide poisoning was considered to be confirmatively diagnosed by detecting and measuring polysuphides and supplementarily sulphide in body tissues, most pertinently in the blood. Two practical cases of suspected poisoning by polysulphides are briefly described.
    Type of Medium: Electronic Resource
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  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric surgery international 9 (1994), S. 261-263 
    ISSN: 1437-9813
    Keywords: Isolated bowel segment (Iowa models) ; Myoenteropexy ; Vascular collaterals ; Viability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An isolated bowel segment (IBS) is created by a two-stage procedure: (1) initial coaptation of the bowel segment to host organs such as abdominal wall muscle, liver, or intestine; and (2) division of its mesentery several weeks later. Between operations, vascular collaterals develop across the coaptation to preserve viability of the IBS. IBS motility and absorption have been observed in previous studies; this experimental study was designed to angio-graphically observe the vascular collaterals. An IBS was created in four dogs by myoenteropexy between the undersurface of the rectus abdominis muscle and a segment of jejunum or colon. Both IBS ends were exteriorized and intestinal continuity was restored. Four weeks later, the IBS mesentery was divided in three dogs and a sham operation was performed in the fourth. Three weeks thereafter, the animals were killed and appropriate arteries related to the IBS were injected with Microfil radiopaque silicone yellow rubber compound at a pressure of 150 mmHg. After the dye had polymerized, soft tissue X-ray was employed to identify vascular collaterals to the IBS. With ipsilateral deep inferior epigastric artery injection in the dogs with IBS mesentery division, the intramural vessels of the IBS filled via collaterals over the myoenteropexy. Dye injected into the IBS mesenteric artery in the fourth dog outlined the abdominal wall vessels via collaterals that had developed across the myoenteropexy. These observations suggest that the IBS is nourished by the abdominal wall vessels through vascular collaterals that have developed across the myoenteropexy during the interval between the staged procedures, and that viability of the IBS is preserved after IBS mesenteric division.
    Type of Medium: Electronic Resource
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  • 40
    ISSN: 1432-2307
    Keywords: Masugi nephritis ; Glomerular damage ; Podocytes ; Focal segmental glomerulosclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We analysed the sequence of structural changes leading to focal segmental glomerulosclerosis (FSGS) in chronic Masugi nephritis. The protocol resulted in an immediate onset of the disease and the development of segmental sclerosis in a considerable proportion of glomeruli within 28 days of serum injection. Throughout the study, the degree of structural damage was significantly correlated with protein excretion. Even 1 day after injection of the serum, the whole spectrum of early lesions was encountered involving all three cell types. Endothelial detachments, mesangiolysis and podocyte foot process effacement were most prominent. There was focal persistence of capillary microthrombosis but, generally, mesangial and endothelial injuries recovered. The development of podocyte lesions was different: on one hand recovery was seen leading to the re-establishment of an interdigitating foot process pattern, and on the other persistent podocyte detachments from peripheral capillaries allowed the attachment of parietal epithelial cells to “naked” portions of the glomerular basement membrane (GBM), and thus to the formation of a tuft adhesion to Bowman's capsule. Progressive podocyte degeneration at the flanks of an adhesion permitted expansion of the adhesion by encroachment of parietal cells onto the tuft along the denuded GBM. Inside an adhesion, capillaries and mesangial areas either collapse or become obstructed by hyalinosis or thrombosis. Resident cells disappear progressively from inside an adhesion; macrophages may invade. Segmental sclerosis in this model consists of collapsed tuft structures adhering broadly to the cortical interstitium. Proliferation of mesangial cells did not contribute to this development. Recovery of endothelial and mesangial lesions was associated with cell proliferation in early stages of the disease; podocyte proliferation was not encountered at any stage. We conclude that the inability to replace an outmatched podocyte crucially underlies the development of sclerosis. Severe podocyte damage cannot be repaired but leads to tuft adhesions to Bowman's capsule followed by progressive collapse of tuft structures inside an adhesion, resulting in segmental glomerulosclerosis.
    Type of Medium: Electronic Resource
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