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Biomedical subjects

C Ruf

Publications and source records attributed to C Ruf.

29 records · Page 2Linked to original sources
PubMed1988

Continuous or bolus chemotherapy with 5-fluoro-2'-deoxyuridine in transplanted experimental liver tumors?

The effect of continuous and discontinuous locoregional chemotherapy with Floxuridine (FUdR) was studied in a standardized and controlled animal model, using the transplantable Novikoff hepatoma in Sprague-Dawley rats. The liver was perfused after transplantation with a total of 420 mg/kg FUdR, via a fully implanted osmotic minipump or miniport and catheter in the hepatic artery, either continuously (n = 22) from day 5 to day 12, or discontinuously (n = 28) on days 5 and 8. Viable tumor volume and peritumorous cell infiltration were measured. No reduction in tumor volume was attained using discontinuous therapy, in contrast to a highly significant reduction using continuous therapy (P less than 0.001). Significantly less cell infiltration was found after discontinuous than after continuous therapy. In conclusion, continuous locoregional chemotherapy with FUdR was the superior administration method on measurable tumor effect, when compared to discontinuous infusion.

Animals↗
PubMed1984

[Cervico-facial suppuration of oro-dental origin due to Eikenella corrodens].

Several cases are reported of cervico-facial suppuration of buccodental origin, the infection being due to Eikenella corrodens, a facultative anaerobic germ that is difficult to culture. Conditions appropriate to the growth of these germs are discussed with respect to etiological, bacteriological and clinical factors. Therapy is outlined and a selective bibliography proposed.

Adult↗
PubMed1982

[Importance of the bacteriologic study in brain abscess. Comparison of the evolution of bacteriologic and therapeutic results in a series of 102 cases].

Progresses in bacteriological study have been analyzed on 102 cases of intracranial infections between 1968 and 1980: sterile cultures decrease from 56% to 11,5%, rate of isolation of anaerobic and association of aero-anaerobic bacteria increase respectively from 10 to 40% and from 2 to 17,1%. Clinical results progress in close relation; the mortality rate decrease from 11,5% to 8,3% as well as morbidity rate from 33% to 19,4%. Moreover clinical results are worse when the bacteriological study fails to isolate any germ: mortality 15,7% and sequellae 53,5%. The best results are observed in the group of anaerobic infections: mortality 4% and sequellae 26,6%. Lastly, the interest of the systematic research of particular bacteria such as capnophilic or microaerophilic bacteria or mycobacterium tuberculosis (2 cases) is underlined. This work emphasizes the importance of the bacteriological study for the management of intracranial infections and the improvement of the clinical results.

Bacteriological Techniques↗
PubMed1981

Affinity labeling of Escherichia coli ribosomes with a covalently binding derivative of the antibiotic pleuromutilin.

Reaction of an alkylating pleuromutilin derivative with E. coli ribosomes led to the binding of the compound to both proteins and RNA. If ribosomes of the E. coli strain MRE600 were used, mainly S18 and L2 became labeled. Ribosomes from E. coli D10 bound the reagent to S18 and frequently to L27 instead of L2. Possibly at slight difference in the structure of these ribosomes exposes different, although closely neighboring, L proteins to the reagent. The simultaneous labeling of L and S proteins seems to reflect the presence of two binding sites for the antibiotic and indicates that the binding sites are located at the interphase region between large and small ribosomal subunits. Analysis of the RNA showed that the affinity label is mainly attached to the 23S species. These data are in good agreement with the known effects of pleuromutilin derivatives on ribosomal functions.

Affinity Labels↗
PubMed1981

Ribosomal binding region for the antibiotic tiamulin: stoichiometry, subunit location, and affinity for various analogs.

Equilibrium dialysis experiments with a highly purified preparation of labeled tiamulin, a semisynthetic derivative of the antibiotic pleuromutilin, and Escherichia coli ribosomes allowed the determination of two binding sites for the drug. The binding reaction showed a cooperative effect. Of the two subunits, the 50S particle was able to bind the antibiotic in a 1:1 stoichiometry. Hence, the 50S subunit contributed predominantly to the binding energy which held the antibiotic to the ribosomes. The 30S subunit, showing no strong affinity for the drug, may be needed for the generation of the second binding site in the 70S particle. If depleted of ammonium ions, 70S ribosomes lost their binding capacity for the antibiotic. The attachment sites for tiamulin could be restored by heating the ribosomes to 40 degrees C in the presence of either ammonium ions or the antibiotic. Other pleuromutilin derivatives displaced labeled tiamulin from its ribosomal binding sites. By quantifying this competition, the relative affinity of various pleuromutilin derivatives for E. coli ribosomes was determined. The binding correlated with the minimal inhibitory concentrations of these compounds against E. coli. When compared with the minimal inhibitory concentrations of these compounds against E. coli. When compared with the minimal inhibitory concentrations against E. coli. When compared with the minimal inhibitory concentrations against Staphylococcus aureus, the correlation was less strict, but the same trend prevailed. These results suggest that the antibacterial activities of various pleuromutilin derivatives on a given test organism are mainly determined by the strength of binding to the ribosomes within the bacterial cell.

Ammonium Chloride↗