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M Rost

Publications and source records attributed to M Rost.

12 recordsLinked to original sources
PubMed1996

Monooxygenation, cytochrome P4501A1 and P4501A1-mRNA in rat liver slices exposed to beta-naphthoflavone and dexamethasone in vitro.

Precision-cut liver slices (0.5 mm) were incubated at 30 degrees C in a modified William's Medium E for up to 48 hrs. During the incubation, K+ and GSH/GSSG concentrations did not decrease. Cytochrome P450-dependent dealkylation rates of 7-ethoxycoumarin (ECOD), 7-allyloxycoumarin (ACOD) and 7-ethoxyresorufin (EROD) decreased to 1/3, 1/2 or did not change at all, respectively, after a 48 hrs incubation period. Exposure of the slices to 25 microM beta-naphthoflavone (beta NF) resulted in about 3 times higher monooxygenation rates. An exposure to a combination beta NF and dexamethasone (10(-6)M) caused a marked induction (6 times higher rates) after 48 hrs. Simultaneously an increase in P4501A1 content was observed. P4501A1-mRNA expression (measured by RT-PCR) was distinctly increased following beta NF exposure for 6 or 24 hrs. DMSO (0.2%) and dexamethasone alone modified monooxygenation rates, but did not have significant effects on P4501A1 content or, in the case of DMSO, P4501A1 gene expression (for dexamethasone not determined). Liver slices are a useful and simple tool for the detection of a beta NF-like induction within a few hours after preparation of the slices.

Animals↗
PubMed1996

Luminol-and lucigenin-amplified chemiluminescence with rat liver microsomes. Kinetics and influence of ascorbic acid, glutathione, dimethylsulfoxide, N-t-butyl-a-phenyl-nitrone, copper-ions and a copper complex, catalase, superoxide dismutase, hexobarbital and aniline.

For the investigation of luminol (LM)-and lucigenin (LC)-amplified chemiluminescence (CL) in rat liver microsomes using both a liquid-scintillation counter (LKB/Wallac 1219 Rackbeta) and a Berthold luminometer (AutoLumat LB 953) optimal incubation mixtures and conditions and basic kinetics have been established. Whereas calibration curves for both LM- and LC-CL are performed with hydrogenperoxide (LC quantum yield is 6.25 fold higher as that of LM), distinct differences were revealed with microsomes, indicating that different reactive oxygen species (ROS) are determined: Both LM- and LC-CL follow the kinetics of enzymatic reactions in terms of dependence on protein and NADPH or NADH concentration, time course, temperature etc., but with differences. LM-CL does not work without addition of Fe2+, whereas LC-CL does. Both copper ions and copper bound in a complex abolish CL, LC-CL being much more sensitive. Isolated cytochrome P-450 (P450) and NADPH P450 reductase from liver of pheno-barbital treated rats alone proved to be inactive in LM-and LC-CL production, whereas te combination 1:1 without and with addition of lipid was highly active in both LM-and LC-CL. Ascorbic acid and glutathione as scavengers diminish both LM- and LC-CL in concentrations higher then 10(5). Dimethyl-sulfoxide (DMSO) was ineffective in LM-CL up to concentrations of 0.2 M, the very high concentration of 2 M diminished LM-CL only to 1/3. LC-CL was diminished starting at concentrations of 100 mM and at 2 M only 10% of maximum LC-CL was observed. The trap substance N-t-butyl-a-phenylnitrone (BNP) also diminished LC-CL more effectively than LM-CL. Clearcut differences were revealed by the addition of catalase and superoxide dismutase: both enzymes diminished LM-CL only, without any influence on LC-CL. Hexobarbital, a potent uncoupler of P450, enhances LM-CL fivefold, whereas LC-CL is barely influenced. Aniline (without uncoupling capability) decreased both LM-and LC-CL increasingly with increasing concentrations. Therefore the conclusion is drawn that LM-CL measures in liver microsomes predominantly superoxide anion radicals, whereas LC-CL is mainly a measure for microsomal hydroxyl radical formation or of reactive organic radicals. With microsomes of phenobarbital and beta-naphthoflavone treated rats CL was much higher but in principle the same kinetic characteristics could be shown. All results on microsomes were obtained uniformly with the liquid scintillation counter and the Berthold luminometer, the letter being much more effective and more sensitive.

Acridines↗
PubMed1995

Prevention of bacterial endocarditis in Germany.

The goal of this study was to assess the current practice of endocarditis prophylaxis in Germany. We conducted a survey using a standardized questionnaire, which was sent to 100 hospital cardiologists, to 430 cardiologists in office practice and to 389 dentists and oral surgeons. In addition, 364 patients with valvular or congenital heart disease were interviewed in our outpatient clinic. Seventy five percent of cardiologists informed their patients by both written and oral instructions. Half recommended the use of penicillin, according to the German Society of Cardiology, while the rest followed recommendations of other societies. Sixty-three percent of patients who had undergone a procedure requiring prophylaxis against bacterial endocarditis within the year prior to the questionnaire, had actually received it. This is higher than previously reported, but is far from acceptable. The indications for prevention of endocarditis, as seen by the dentists, deviated markedly from official recommendations. Although 77% administered antibiotics themselves, in only 57% did the type of prophylaxis applied correspond to one of the available recommendations. Recommendations on the prevention of bacterial endocarditis are not well known dentists and oral surgeons who perform procedures for which it is indicated. Further patient- and physician-oriented strategies are urgently needed to improve compliance with prevention of endocarditis in Germany.

Anti-Bacterial Agents↗
PubMed1994

The ambiguous effect of ascorbic acid on chromate induced proteinuria in rats.

The influence of ascorbic acid (AA, 5 g/kg body weight) on chromate (Cr, 10 mg/kg) induced proteinuria, which is a sensitive parameter of its nephrotoxicity, was investigated in adult female Wistar rats. The concentrations of Cr and ascorbic acid (AA) were determined in renal tissue. Cr nephrotoxicity is related to its intracellular reduction from Cr(VI) to Cr(III). Proteinuria was completely prevented by enhancement of extracellular reduction of Cr(VI) to Cr(III) followed by rapid renal excretion when Cr and AA were given concomitantly. With an interval up to 1 h between Cr and AA, proteinuria was decreased probably by the radical scavenging function of AA. At an interval of 3 h AA enhanced Cr toxicity by increased intracellular Cr reduction. If the interval was increased to 5 h or if Cr was given 24 h after AA, no influence of AA could be detected. Our results confirm that AA is a very effective reductant of Cr which can influence Cr nephrotoxicity in very high concentrations. It depends on the interval between Cr and AA administration whether or not there is a beneficial effect of AA in Cr nephrotoxicity.

Animals↗
PubMed1992

Clinical study on the effect of amine fluoride/stannous fluoride on exposed root surfaces.

The aim of this study was to assess the remineralizing effect of an amine fluoride (AmF)- and stannous fluoride (SnF2)-containing toothpaste and mouthrinse on exposed root surfaces. A total of 44 adults participated in the 20-week, double-blind study and were grouped as follows: (1) 20 participants (mean age 45.7 years) used an AmF/SnF2 experimental toothpaste plus AmF/SnF2 (Meridol) mouthwash, and (2) 24 participants (mean age 48.8 years) used an NaF-containing toothpaste and mouthrinse. Root caries index (RCI) and root surface scores were determined by a modified method of Katz (J Dent Res, 1984). RCI mean values showed decreases of approximately 47% in the AmF/SnF2 group, and 10% in the NaF group. With respect to root caries scores, the number of persons with decreased softened (non-carious) surfaces between the baseline and control examinations was statistically significant (p less than 0.05) in the AmF/SnF2 group but not significant in the NaF group. A statistically significant difference (p less than 0.05) in the results of the groups favored the AmF/SnF2 subgroup. Thus, the data point to a possible remineralizing effect of topically applied AmF/SnF2 on softened root caries surfaces.

Amines↗
PubMed1991

[The effect of mouthwashes containing amino-fluoride and stannous fluoride on plaque formation and gingivitis in adults].

UNLABELLED: The aim of the study was to assess the effect of amine fluoride (AmF)--stannous fluoride (SnF2) containing toothpaste and mouthrinsing on dental plaque accumulation and gingivitis. The examinations were performed on two groups of 20 (using AmF/SnF2)-, resp. 24 (using NaF) participants. The mean age was 45.6-, resp. 48.8 years. The duration of the study was five months. Toothbrushing was performed with standardized (multi-effect) toothbrushes, and after it mouthrinsing twice a day. Dental plaque was scored with the Plaque Index of Silness and Löe (1964) and gingivitis was assessed by the modified Sulcus Bleeding Index (Mühlemann and Son 1971) Plaque Index mean values showed a significant decreased in both groups (p less than 0.01). The reduction in the AmF/SnF2 group was more pronounced (63.7%) than in the NaF group (39.3%). The Sulcus-Bleeding Index mean values decreased also significantly in both groups (p less than 0.01). The decrease in the AmF/SnF2 group was 56.5% and in the NaF group 39.0%. CONCLUSION: in the course of a five-month's period AmF/SnF2 containing toothpaste and mouthrinsing had better clinical effect on plaque accumulation and gingivitis than NaF containing toothpaste and mouthrinsing.

Adult↗
PubMed1979

[Fluid crystals of cholesterol-a new aid in the study of circulation].

A measuring method for model investigations is described. It is suitable for the velocity measurement and for evidence of strong local distortions of the velocity profile. The basis for this method are the regularities of the heat transport in streaming fluids. It was tested on silicone tube branches with a straight main branch. Clinically interesting induced flows can be produced if the flow is interrupted in one branch. A limited fluid exchange takes place in the closed branch then. This is important for the diagnostic and the planning of vascular surgery measures.

Cholesterol↗
PubMed1976

An improved method for staining cells of the endocrine polypeptide (APUD) series by masked metachromasia: application of the principle of 'fixation by excluded volume'.

Masked metachromasia is demonstrated by staining with a metachromatic basic dye, after acid hydrolysis of suitably fixed tissue. We report that the addition of 20% Carbowax 20M (an inert polyer, mol. wt. about 20,000) to the hydrolysis mixture improved the reaction. The improved method gives increased metachromasia , greater tolerance to variations in hydrolysis conditions, and demonstrates a greater proportion of cells--presumably due to a lower threshold of sensitivity. Lower molecular weight polymers (Carbowax 1000, Carbowax 6000) are less effective.

Animals↗
PubMedDate not supplied

Beneficial effect of acetylcysteine on cisplatin nephrotoxicity in rats.

The influence of acetylcysteine (ac-cys) on cisplatin (CP) nephrotoxicity was investigated in female Wistar rats. Administration of 0.6 mg CP 100 g-1 body wt. was followed by oliguria and proteinuria, as well as a significant increase of blood urea nitrogen concentration. The i.p. administration of 0.6 mg CP 100 g-1 body wt. concomitantly with 100 mg ac-cys 100 g-1 body wt. s.c. completely abolished the nephrotoxic effects of CP. However, following this, the Pt concentration in kidney was decreased significantly by ac-cys treatment. This was caused by the enhanced urinary excretion of Pt. The same effect on CP nephrotoxicity appeared when CP and ac-cys were dissolved together in solution prior to injection. It could be shown that in this solution a ligand exchange reaction of CP by ac-cys started immediately, resulting in increased renal excretion and decreased Pt concentration in kidney. From our results we concluded that the protective effect of ac-cys on CP nephrotoxicity is based on the formation of a complex unsuitable for tubular reabsorption.

Acetylcysteine↗
PubMedDate not supplied

[Study of the effectiveness of amine fluoride and stannous fluoride containing toothpaste and mouthwash].

AmF and SnF2 containing toothpastes (equally 750 ppm F-) and mouthrinses (equally 125 ppm F-) from the GABA International Agency were tested. After a five month treatment period (daily two times tooth cleaning), in the saliva of the examined persons the germ counts of the S. mutans and Lactobacillus showed a decreasing tendency, though the change was not statistically significant. The control group used NaF containing cleaners (toothpaste; 1500 ppm F-, mouthrinse; 250 ppm F-) for also a five month treatment period. Within this group the germ counts of the microorganisms of the examined saliva did not change markedly.

Amines↗