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  • 1
    ISSN: 1434-0879
    Keywords: Renal cell carcinoma ; Renal tubular transport ; Renal cortical slices ; p-Aminohippurate ; Human ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In vitro accumulation ofp-aminohippurate (PAH) was investigated in “intact” human renal cortical slices of normal kidney tissue and in tissue slices of renal cell carcinoma (RCC). The technique used was established in preliminary experiments on rat kidney tissue slices. In principle, the accumulation capacity is comparable in renal tissue slices of both species (slice to medium accumulation ratios between 4 and 8). In man sex differences in accumulation capacity do not exist. But, as shown in detail for rats, accumulation capacity drops with age. Tissue slices of RCC are unable to accumulate PAH actively; slice to medium ratio reaches about 1 and indicates passive PAH uptake only. Surprisingly, in tumors of stage pTl PAH uptake is lowest, perhaps as a sign of PAH transport out of the cells. There is no difference between peripheral and central parts of RCC. Age and sex are without influence on PAH uptake in RCC tissue slices. Interestingly, the accumulation capacity of “intact” tissue of kidneys infested with RCC also depends on the severity of the tumor (stage, diameter), but not on grading and formation of metastases.
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  • 2
    ISSN: 1434-0879
    Keywords: Key words Renal tubular transport ; p-Aminohippurate ; Stimulation ; Renal cell carcinoma ; Dexamethasone ; Triiodothyronine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This paper is the third of a long-term planned series of papers dealing with ex vivo investigations of drug transport in human kidney. The aims of this study are (a) to investigate whether or not human renal cell carcinoma (RCC) can actively accumulate p-aminohippurate (PAH) and (b) to test the response of RCC on dexamethasone or triiodothyronine (T3) using tissue slices ex vivo. By this approach, the accumulation capacity of RCC should be stimulated as a prerequisite for an increased uptake of anti-tumour drugs. Tissue slices of RCC samples of 30 patients were incubated for 24 h in Williams medium E containing 0.01–50 μM dexamethasone or T3. Thereafter, slices were placed in PAH-containing Cross–Taggart medium, and PAH uptake into kidney tissue was measured for 2h under standardised conditions as described previously. In intact human renal cortical slices, PAH uptake capacity, expressed as slice to medium ratio (Q S/M), was about 2.8 ± 0.16 after 24 h of incubation and increased significantly in dexamethasone-containing medium in a concentration-dependent manner, up to ∼150%, whereas T3 did not influence PAH accumulation. On the other hand, in RCC the PAH accumulation capacity was completely abolished (Q S/M∼1). However, after administration of dexamethasone, the accumulated amount of PAH increased significantly in RCC tissue in a concentration-dependent manner, up to ∼190%. T3 was without effect in RCC, too. Surprisingly, the dexamethasone-mediated stimulation could be differentiated into responders and non-responders, with maximal effects at different concentrations for each patient. Nevertheless, the maximal transport rates remained low in RCC, even under hormone influence. In conclusion, a moderate stimulation of tubular transport capacity can be shown ex vivo in human RCC. This phenomenon is only of a relatively low degree compared with intact renal tissue. However, in principle, the response of RCC on dexamethasone could form a basis for further therapeutic strategies to overcome multi-drug resistance in RCC patients. For this purpose, additional experiments analysing the expression of transporters of the ABC cassette-type are in progress.
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  • 3
    ISSN: 1434-3940
    Keywords: Schlüsselwörter ; Odontogene Infektionen ; Anaerobe Keime ; Penizillinresistenz ; Key words ; Odontogenic infections ; Anaerobic bacteria ; Resistance to penicillin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Out of 440 dentogenic pyogenic infections, 171 exclusively caused by anaerobes were investigated to understand the importance of anaerobic bacteria in dental pyogenic processes better. Grampositive anaerobic bacteria dominated. The predominant grampositive isolates in monoinfections were Peptostreptococci and in the case of mixed infections, strains of the genus Eubacterium. Strains of Prevotella and Porphyromonas dominated the gramnegative anaerobic spectra. The resistance to penicillin was very low. Altogether, only one strain of Prevotella oris and one strain of Prevotella oralis showed resistance to penicillin.
    Notes: Zum besseren Verständnis der Bedeutung einzelner anaerober Spezies bei odontogenen pyogenen Infektionen wurden von 440 Fällen jene 171 ausgesucht, bei denen ausschließlich anaerobe Keime mikrobiologisch nachgewiesen werden konnten. Hierbei dominierten grampositive Spezies im Vergleich zu gramnegativen. Bei anaeroben Mischinfektionen überwogen unter den grampositiven Keimen Stämme des Genus Eubacterium, bei Monoinfektionen hingegen Stämme des Genus Peptostreptococcus. Unter den gramnegativen Anaerobiern wurden am häufigsten Prevotella- und Porphyromonasarten isoliert. Bei den 171 odontogenen Infektionen wurde eine sehr niedrige Quote penizillinresistenter Stämme beobachtet. Nur 2 Stämme von Prevotella oris bzw. Prevotella oralis waren gegenüber Penizillin resistent.
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