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  • 2005-2009
  • 1990-1994  (5)
  • Sodium dichromate  (3)
  • Accuracy  (1)
  • Characterization  (1)
Materialart
Erscheinungszeitraum
  • 2005-2009
  • 1990-1994  (5)
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 66 (1992), S. 646-651 
    ISSN: 1432-0738
    Schlagwort(e): Sodium dichromate ; Nephrotoxicity ; Glutathione ; Ascorbate ; Carbohydrate metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Ascorbate treatment 30 min prior to sodium dichromate (20 or 30 mg/kg, s.c.) shows higher potency than that of glutathione (GSH) in protecting against both the metabolic disturbance and nephrotoxicity induced by dichromate. However, ascorbate treatment after 2 h of dichromate intoxication had no effect on dichromate-induced blood urea nitrogen (BUN) elevation 3 days after intoxication. In contrast, dichromate-induced glucosuria, which reached maximum levels at 3 days after treatment, was significantly decreased by GSH or N-acetyl cysteine (NAC) treatment, even if its administration was after 24 h of dichromate intoxication. Pretreatment with GSH depletors such as diethyl maleate (DEM) and buthionine sulfoximine (BSO) had no effect on dichromate-induced nephrotoxicity. GSH levels in the liver and kidney were not affected at 3 h after dichromate treatment. However, dichromate significantly increased tissue GSH levels with a marked increase in liver per kidney GSH ratio at 24 h after treatment, if food was withheld subsequent to dichromate treatment, indicating that GSH biosynthesis resulted from the accelerated protein breakdown. These results suggest that GSH-mediated dichromate reduction is not a kinetically favorable pathway in vivo; however, GSH plays an important role in protection against dichromate-induced nephrotoxicity. In addition, the cellular metabolism of dichromate in the early period after treatment is important in the pathogenesis of its nephrotoxicity.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 64 (1990), S. 644-649 
    ISSN: 1432-0738
    Schlagwort(e): Sodium dichromate ; Glycolysis ; Hyperglycemia ; Glycogenolysis ; Cyanosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The effect of sodium dichromate on cellular metabolism was investigated. Intraperitoneal injection of sodium dichromate into the rat (20 or 40 mg/kg) caused significant increases in serum lactate, pyruvate, and creatinine concentrations within 15 min after intoxication. Severe hyperglycemia occurred thereafter, as a result of increased hepatic glycogenolysis, which was seen in the first 2 h after dichromate. However, liver glycogen was resynthesized in 24 h-fasted rats after glucose refeeding. Dichromate decreased serum total amino acids, with a consequent increase in blood urea nitrogen (BUN) concentration. Unlike HgCl2 (2 mg/kg, i.p.), As2O3 (5 mg/kg, i.p.), and KCN (5 mg/kg, i. p.), dichromate showed the largest metabolic disturbance only in the early period after treatment. In addition, dichromate produced cyanosis, which appeared during the period of the accelerated glycolysis and breakdown of creatine phosphate. Regardless of chemical species, only the hexavalent chromium compounds had an effect on the cellular metabolism. Trivalent chromium compounds had no effect at all. These results suggest that dichromate possesses a characteristic dual action on cellular metabolism, which might be related to its metabolic fate.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 65 (1991), S. 537-541 
    ISSN: 1432-0738
    Schlagwort(e): Sodium dichromate ; Nephrotoxicity ; Hepatotoxicity ; Lipid peroxidation ; Phenobarbital
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A comparison of the effects of intraperitoneal and subcutaneous routes of administration of sodium dichromate on nephrotoxicity in rats was studied. Dichromate when injected subcutaneously (SC group) produced a higher degree of nephrotoxicity than when administered intraperitoneally (IP group). It caused severe progressive proteinuria followed by polyuria and glucosuria, reaching maximum levels at 3 days after treatment in the SC group, whereas it produced mild proteinuria without glucosuria in the IP group. The dose-dependent increases in blood urea nitrogen (BUN) and creatinine concentrations, shown in the SC group, were not observed in the IP group. However, between the two groups, there were no great differences in either the urinary excretion rate of chromium or the electrophoretic patterns of urinary protein in the day 1 urine specimens. Pretreatment of phenobarbital (PB) had no remarkable effect on the dichromate-induced nephrotoxicity. In contrast, it potentiated dichromate-induced hepatotoxicity, the indices of which were the elevation in serum alanine aminotransferase (ALT) activity and hepatic lipid peroxide formation. These results suggest that the dependence of dichromate-induced nephrotoxicity on the route of administration is related to the chemical forms of chromium reaching the kidney, and the necrotizing property of dichromate results from its metabolic fate in vivo.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 243 (1994), S. 225-233 
    ISSN: 1617-4623
    Schlagwort(e): Protein synthesis ; Translation ; Accuracy ; Macrolide antibiotics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Inaccurate protein synthesis produces unstable β-galactosidase, whose activity is rapidly lost at high temperature. Erythromycin, lincomycin, clindamycin, and celesticetin were shown to counteract the error-inducing effects of streptomycin on β-galactosidase synthesized in the antibiotic-hypersensitive Escherichia coli strain DB-11 Met −. Newly synthesized β-galactosidase was more easily inactivated by high temperatures when synthesized by bacteria partially starved for arginine, threonine, or methionine. Simultaneous treatment with erythromycin or linocomycin yielded β-galactosidase that was inactivated by high temperatures less easily than during starvation alone, an effect attributed to stimulation of ribosome editing. When synthesized in the presence of canavanine, β-galactosidase was inactivated by high temperature more easily but this effect could not be reversed by erythromycin. The first arginine in β-galactosidase occurs at residue 13, so the effect of erythromycin during arginine starvation is probably to stimulate dissociation of erroneous peptidyl-tRNAs of at least that length. Correction of errors induced by methionine starvation is probably due to stimulation of dissociation of erroneous peptidyl-tRNAs bearing peptides at least 92 residues in length. All the effects of erythromycin or the tested lincosamides on protein synthesis are probably the result of stimulating the dissociation from ribosomes of peptidyl-tRNAs that are erroneous or short.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Annals of the Institute of Statistical Mathematics 46 (1994), S. 351-360 
    ISSN: 1572-9052
    Schlagwort(e): Characterization ; exponential distribution ; gamma distribution ; geometric distribution ; Poisson process ; renewal process
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract Given two independent positive random variables, under some minor conditions, it is known that fromE(Xr∥X+Y)=a(X+Y)r andE(Xs∥X+Y)=b(X+Y)s, for certain pairs ofr ands, wherea andb are two constants, we can characterizeX andY to have gamma distributions. Inspired by this, in this article we will characterize the Poisson process among the class of renewal processes via two conditional moments. More precisely, let {A(t), t≥0} be a renewal process, with {S k, k≥1} the sequence of arrival times, andF the common distribution function of the inter-arrival times. We prove that for some fixedn andk, k≤n, ifE(S k r ∥A(t)=n)=atr andE(S k s ∥A(t)=n)=bts, for certain pairs ofr ands, wherea andb are independent oft, then {A(t), t≥0} has to be a Poisson process. We also give some corresponding results about characterizingFto be geometric whenF is discrete.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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