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  • 1
    Call number: MOP 43800 / Mitte
    In: Technical papers in hydrology
    Type of Medium: Monograph available for loan
    Pages: 49 S.
    Series Statement: Technical papers in hydrology 8
    Location: MOP - must be ordered
    Branch Library: GFZ Library
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  • 2
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Wenn Stubenfliegen (Musca domestica) Pyrethrin-Rückständen verschiedener Konzentration ausgesetzt werden, stellen die Zeiten, die zur Abtötung der Hälfte der Insekten erforderlich sind (LD 50), vergleichbare Indizes für die Giftreaktionsraten dar. Es besteht auch die Wahrscheinlichkeit, daß die unbekannten Pyrethrin-Konzentrationen, die im Körperinneren erreicht werden, den bekannten Außenkonzentrationen direkt proportional sind. Infolgedessen können die offensichtlichen Größenordnungen der Vergiftungsreaktion in Gegenwart verschiedener Konzentrationen des Insektizids und des Synergisten geschätzt werden, und von Änderungen in der offenbaren Größenordnung können Rückschlüsse auf die Natur der beteiligten Prozesse gezogen werden. Bei normalen sowie resistenten Fliegen bewirkte die Hinzufügung des Synergisten, Piperonylbutoxyd (PB), in den Giftbelägen eine Verminderung der scheinbaren Größenordnung der Reaktion, welche sich dem Wert 2 näherte, wenn die PB-Konzentration vergrößert wurde. Jedoch waren zur Erreichung dieses Zieles bei den resistenten Fliegen größere Konzentrationen notwendig. Diese wiesen auch mit Pyrethrin allein eine höhere Größenordnung der Reaktion auf. Es muß deshalb geschlossen werden, daß normalerweise ein beträchtlicher Teil des absorbierten Pyrethrins in nichttoxische Reaktionswege abgelenkt wird. Die beobachtete Toxizität ist nur dem Pyrethrin-Anteil proportional, der nicht auf diese Weise verlorengeht, und erweckt deshalb im Verhältnis zu dem insgesamt eingedrungenen Pyrethrin den Anschein einer höheren Reaktionsordnung. Wird die PB-Konzentration verstärkt, so wird die Pyrethrin-Fraktion, die unschädlich gemacht wird, zunehmend reduziert, und bei PB-Konzentrationen von mehr als 0,15 mg/sq.ft (=1,6×10-4 mg/cm2) nimmt das gesamte von normal empfindlichen Fliegen absorbierte Pyrethrin an der bimolekularen toxischen Reaktion teil. Resistente Fliegen machen eine noch größere Fraktion des absorbierten Pyrethrins unschädlich und täuschen bei alleiniger Gegenwart von Pyrethrin konsequentermaßen eine noch höhere Größenordnung der toxischen Reaktion vor. Auch ihr Entgiftungsmechanismus kann durch PB gehemmt werden, doch sind dazu höhere Konzentrationen des Synergisten von der Größenordnung von 18 mg/sq.ft (=19,4×10-3 mg/cm2) notwendig.
    Notes: Abstract Virgin female house flies, Musca domestica L., one day of age, were exposed at 32° C for measured periods of time to deposits on glass of six concentrations of pyrethrins (Py) and to 42 Py-piperonyl butoxide (PB) mixtures. The percentage mortality at 18 to 20 hr after exposure was recorded, and the duration of exposure required for 50% kill (Lt50) was calculated for each treatment from the regression of probit kill on log exposure time. Comparison of the Lt50's for these normally susceptible flies at different Py concentrations indicated that the apparent order of the toxic reaction was about 4.5 with residues that contained Py alone. In the presence of PB, the apparent order was reduced progressively approximately to 2. These observations are interpreted in support of the hypothesis that flies possess a mechanism for detoxifying Py, and that PB exerts its synergistic action by interfering with the detoxication process. Similar data from a strain of flies selected for over 90 generations for Py-resistance suggest that the selected strain possesses a more active detoxifying mechanism, which need not differ qualitatively from that present in the unselected population. The development of direct biochemical and physiological evidence in reference to these problems is urged.
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  • 3
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Wenn die Geschlechter zweier Stubenfliegen-Stämme (ein normal empfindlicher und ein DFP-resistenter) getrennt DFP-Dämpfen ausgesetzt wurden, waren die entsprechenden Reihen der log Lt‘50’ zwar verschieden, wurden jedoch in jedem Falle linear abhängig von der logarithmischen DFP-Konzentration und einander parallel befunden. Für alle vier Gruppen betrugen die erkennnbaren Werte der toxischen Reaktion etwas mehr als 2,5. Da die tatsächliche toxische Reaktion bimolokularer Kinetik zu gehorchen scheint, wird geschlossen, daß ein beträchtlicher Anteil des von den Fliegen absorbierten DFP in nicht-toxische Prozesse abgeleitet wird. Die Ergebnisse liefern keinerlei neue Erklärung der Toleranzunterschiede zwischen den Geschlechtern und Stämmen, und infolgedessen bleiben die Ursachen für diese Unterschiede unbekannt. Im Durchschnitt war die Hemmung der Cholinesterase des Kopfes direkt proportional zum Abtötungsprozentsatz, trotz des Vorliegens einer beträchtlichen Variabilität, welche zufallsmäßig war und offensichtlich auf inneren Faktoren beruht. In dieser Hinsicht bestanden keine signifikanten Unterschiede zwischen den Geschlechtern und Stämmen. Das beobachtete Verhältnis wird als strenger Beweis für ein kausale Beziehung zwischen Cholinesterase und Giftwirkung angesehen, jedoch wird der Grad der Kopf-Cholinesterase-Hemmung nur als Index für ein unbekanntes Ausmaß der Hemmung an anderen hypothetisch vitalen Punkten betrachtet. Die Befunde liefern weder Anhaltspunkte für noch wider die Auffassung, daß ein Acetylcholin-Cholinesterase-Mechanismus der synaptischen Übertragung eine vitale Funktion im Insekt besitzt.
    Notes: Abstract The dosage-mortality relationship for normally susceptible and di-isopropylphosphorofluoridate (DFP)-resistantMusca domestica L. was determined by means of vapor exposures of varied durations and concentrations. With reference to concentration, males of either strain were approximately 1.5 × as sensitive as the respective females, and the strains differed by a factor of about 10. Probit kill at each concentration was proportional to log exposure time for all four groups, and the log of time required to kill half a given sex or strain (log Lt50) was proportional to the log of DFP concentration. For all four groups the apparent order of toxic reaction was the same, — namely slightly more than 2.5. Since the actual toxic process probably is a bimolecular reaction between DFP and nervous system cholinesterase (ChE), the observations indicate that an appreciable portion of the entering DFP was diverted to nontoxic pathways. The data contain no suggestion that the sexes and strains are distinguished by any qualitative differences in these pathways. The differences in tolerance are significant but unexplained. With all four groups, like percentages of kill were accompanied on the average by like percentages of inhibition of head ChE despite considerable intergroup differences in the dosages required. Per cent inhibition was directly proportional to kill. The overall correlation observed corroborates the view that inhibition of central nervous system ChE is related causally to toxicity. In general, flies whose head ChE was inhibited less than about 50% did not succumb, while those with more than 50% inhibition died irrespective of their source and the dose of DFP needed. Although the relationship favors the conclusion that ChE inhibition is instrumental in the toxicity of DFP, it does not indicate that inhibition of head ChE is more than an indirect index of events at the as yet unknown true sites of action, nor that an acetylcholine-ChE mechanism of synaptic transmission is vitally involved in the functioning of insect nerve.
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  • 4
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An infant with an interstitial deletion of chromosome 16 is reported. He showed severe psychomotor retardation and multiple congenital anomalies (craniofacial dysmorphism, cleft palate, endocardial cushion defect, preaxial polydactyly of one hand, low total ridge count). Unbanded chromosome studies following amniocentesis failed to identify the deletion. This case is very similar to other cases in the literature which were reported first by Fryns et al. (1977).
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  • 5
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A family is described in which four affected males, spanning two generations, have hyperuricemia and gout accompanied by hematuria but are without severe neurologic involvement. The affected males were found to have markedly reduced levels of erythrocytic hypoxanthine-guanine phosphoribosyltransferase (HGPRT) activity; these were 5–12% with hypoxanthine and 0.5–3% with guanine as compared to controls. Erythrocytic adenine phosphoribosyltransferase (APRT) was approximately three-fold elevated in the affected individuals. The residual HGPRT activity in affected males enabled characterization of some of the properties of this mutation. The apparent Michaelis constants (km) for both hypoxanthine and guanine were essentially unchanged, whereas the km for PP-ribose-P was approximately 10–20-fold elevated for all four affected males. The enzyme was more sensitive to product inhibition by IMP and GMP than controls, and exhibited greater thermal lability at 65°C than found with control lysates.
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  • 6
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A female infant with multiple congenital anomalies is presented. Cytogenetic study revealed the presence of a de novo, supernumerary, small telocentric chromosome exhibiting the banding pattern of the short arm of chromosome no. 10 [47,XX,+10p(pter→cen)]. Her clinical features were compatible with the 10p trisomy syndrome. Hexokinase (HK-1) activity was elevated in the patient's erythrocytes, which is consistent with an assignment of HK-1 to 10pter→cen10. The absence of a gene dosage effect for inorganic pyrophosphatase (PP) in this study indicates exclusion of PP from 10pter →cen10, and therefore implies a regional assignment of cen10→10q24 for PP. Adenosine kinase (ADK) activity was within control limits, which is consistent with exclusion of ADK from 10pter→cen10.
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  • 7
    ISSN: 0003-9861
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0003-9861
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0003-9861
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0003-9861
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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