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Biomedical subjects

K Naber

Publications and source records attributed to K Naber.

At least 19 recordsLinked to original sources
PubMed2006

[Therapy of the acute uncomplicated urinary tract infection].

Acute uncomplicated cystitis and acute uncomplicated pyelonephritis are two frequently encountered urinary tract infections (UTI) in premenopausal, healthy females. Recent epidemiological investigations showed that the incidence of these infections is higher than expected. Surveys on healthcare practices in North America revealed a high variability in the therapy of uncomplicated UTI. Standardized criteria for diagnosis and therapy of uncomplicated UTIs therefore are important in order to achieve sufficient sensitivity and specificity in clinical practice. The Infectious Diseases Society of America (IDSA) developed evidence-based guidelines for the treatment of acute uncomplicated cystitis and acute uncomplicated pyelonephritis, which were recently updated by other expert groups.

Acute Disease↗
PubMed2003

[Infection-induced urinary stones].

Infection stones make up approximately 15% of urinary stone diseases and are thus an important group. These stones are composed of struvite and/or carbonate apatite. The basic precondition for the formation of infection stones is a urease-positive urinary tract infection. Urease is necessary to split urea into ammonia and CO(2). As a result, ammonia ions can form and at the same time alkaline urine develops, both being preconditions for the formation of struvite and carbonate apatite crystals. When these crystals are deposited infection stones form. Pathogenetically, various risk factors play a role: urinary obstruction, neurogenic bladder, dRTA, and MSK. If these infections are not treated and the stones are not removed, the kidney will be damaged. Modern methods are available for stone removal, e.g., ESWL and/or instrumental urinary stone removal. Here, especially less invasive methods are preferable. Any treatment must be adjusted to the patient individually. Patients should be examined frequently for recurrent urinary tract infections and stone recurrences, and new infections must be resolutely treated. Good therapy and prophylaxis are possible with present-day treatment modalities.

Apatites↗
PubMed2002

Urinary infection stones.

Infection stones make up approximately 15% of urinary stone diseases and are thus an important group. These stones are composed of struvite and/or carbonate apatite. The basic precondition for the formation of infection stones is a urease positive urinary tract infection. Urease is necessary to split urea to ammonia and CO(2). As a result, ammonia ions can form and at the same time alkaline urine develops, both being preconditions for the formation of struvite and carbonate apatite crystals. When these crystals deposit themselves infection stones form. If these infections are not treated and the stones are not removed, the kidney will be damaged. For stone removal modern methods are available, e.g. ESWL and/or instrumental urinary stone removal. Here especially less invasive methods are preferable. Any treatment must be adjusted to the patient individually. Patients should be examined frequently for recurrent urinary tract infections and stone recurrences and, newly arising infections must be resolutely treated. Good therapy and prophylaxis are possible with present-day treatment modalities.

Anti-Bacterial Agents↗
PubMed2000

National and local antibiotic policies in Central and Eastern Europe.

To assess the antibiotic policies of Central European countries, we performed an overview of antibiotic stewardship, prescription habits and antibiotic prescription regulatory procedures. Since most Central European countries have had centralized health care and drug policies, the situation 10 years after decentralization is surprising. Only 3 of 10 Central European countries have some regulation of prescription of antibiotics, only 4 restrict some antibiotics, only 5 have hospital and only 3 national antibiotic policies. In all but 3 countries physicians can prescribe quinolones and/or 3rd generation oral cephalosporins as first-line antibiotics. Information on local and national antibiotic policies in Central and Eastern European countries is given including prescription guidelines for antibiotic use in community and hospital.

Anti-Bacterial Agents↗
PubMed1989

Pharmacokinetic disposition of quinolones in human body fluids and tissues.

The unique pharmacokinetic properties as well as the body fluid and tissue penetration of quinolones are discussed. Quinolones are well absorbed from the gastrointestinal tract and are eliminated with considerable differences in their terminal half-lives. The major elimination pathways of quinolones are renal excretion and hepatic metabolism. Renally, these drugs undergo the potential excretion mechanisms (glomerular filtration, tubular secretion, reabsorption). In the liver, they are metabolised primarily by oxidation as well as by conjugative pathways. However, the metabolic pattern and extent of metabolism differ significantly between individual agents. Alterations in the pharmacokinetic disposition of these agents in liver and renal failure as well as in elderly patients are observed as predicted from their excretion pattern. In addition, quinolones can interact with a number of other compounds at hepatic (e.g. with xanthine derivatives), renal (with probenecid) and gastrointestinal (with antacids) sites. The volume of distribution of quinolones is considerably higher than body volume, which suggests intracellular penetration. Studies on tissue penetration show that concentrations exceeding plasma levels are obtained in most tissues. The highest tissue/plasma concentration ratios are achieved in lung and kidney, whereas concentrations in fat are considerably lower than in plasma. Body fluid penetration is introduced as a new approach to evaluate distribution kinetics of quinolones. With the exception of those in nasal secretions and ejaculate, body fluid levels of these drugs rarely reach plasma levels. The body fluid penetration model allows for differentiation among individual agents. There is no apparent relationship between differences in body fluid penetration of quinolones and differences in volume of distribution. For the clinical use of these drugs it is important that the concentrations achieved in body fluids and tissues are sufficient to kill most pathogens. A discussion on the relationship between plasma and tissue levels and the MICs of quinolones is, however, beyond the scope of this article.

4-Quinolones↗
PubMed1989

[Hemostasis disturbance caused by cephalosporins with an N-methylthiotetrazole side chain. A randomized pilot study].

The mechanism of hypoprothrombinemia induced by cephalosporins containing the N-methylthiotetrazole (NMTT) side chain has been investigated in a randomized clinical, trial (pilot study) with 14 hospitalized patients (main inclusion criteria: age greater than or equal to 50 years, urinary tract infection, normal prothrombin time. Therapy groups: latamoxef (n = 5), cefoperazone (n = 5), cefotaxime (control, n = 4). Duration of treatment: 7 days). Two patients under cefoperazone exhibited a significant increase of prothrombin time, accompanied by the appearance of PIVKA II (prothrombin induced in vitamin K absence). Both cefoperazone (in 4 patients) and latamoxef (in 3 patients) caused the appearance of endogenous vitamin K1 2,3-epoxide, whereas cefotaxime did not. This confirms the hypothesis that NMTT-cephalosporins are inhibitors of hepatic vitamin K epoxide reductase, and that this is at least partly responsible for the clinically observed hypoprothrombinemia. In older patients treated with these antibiotics, prothrombin time should be controlled before as well as under therapy. Unexpectedly, the patients displaying an appearance of vitamin K1 2,3-epoxide showed a statistically significant increase of endogenous plasma vitamin K levels. This effect needs further investigation.

Aged↗
PubMed1988

Pharmacokinetics and body fluid penetration of fleroxacin in healthy volunteers.

The pharmacokinetics of fleroxacin after oral administration of 400 mg fleroxacin in twelve healthy volunteers were investigated. All drug analysis was carried out by HPLC. Pharmacokinetic analysis was done by non-compartmental methods. We found that fleroxacin achieves high plasma levels of 5.2 +/- 1.1 mg/l after 1.2 +/- 0.7 h. The high AUC-value of 60.4 +/- 8.4 mg.h/l is the result of complete absorption and the long half-life of 10.8 +/- 1.6 h. The total, renal and non-renal clearance of fleroxacin were 107.9 +/- 15.1, 67.6 +/- 11.8 and 40.3 +/- 14.5 ml/min respectively. The volume of distribution Vd beta/F was 101.4 +/- 21.9 or 1.32 +/- 0.28 l/kg. Fleroxacin penetrated well into saliva (66%), nasal secretions (223%), tears (69%) and sweat (43%). On the basis of these findings once a day administration deserves consideration in the further clinical development of fleroxacin.

Adult↗
PubMed1988

Metabolism of fleroxacin in man.

The metabolism of fleroxacin was studied in 12 healthy volunteers by use of a newly developed high pressure liquid chromatographic assay. Desmethylfleroxacin and fleroxacin N-oxide were identified as the major metabolites of fleroxacin in plasma and urine. The maximum concentrations of fleroxacin, desmethylfleroxacin and fleroxacin N-oxide in plasma were 5.2 +/- 1.1, 0.0683 +/- 0.0151 and 0.0634 +/- 0.0090 mg/l reached at 1.2 +/- 0.7 h, 2.2 +/- 0.8 h and 6.2 +/- 2.4 h respectively (one subject excluded from analysis). The plasma AUC was between 1.0 and 2.6 mg.h/l for either metabolite and between 47.9 and 75.1 mg.h/l for the parent compound. The terminal half-life of desmethylfleroxacin was higher than that of unchanged fleroxacin and similar to the half-life of fleroxacin N-oxide. In urine unchanged fleroxacin, desmethylfleroxacin and fleroxacin N-oxide accounted for 59.9%, 6.8% and 6.3% of the dose of fleroxacin. The renal clearance of fleroxacin, desmethylfleroxacin and fleroxacin N-oxide were 67.6, 300.9 and 324.8 ml/min respectively. We conclude that demethylation and N-oxidation of fleroxacin affects the distribution and elimination characteristics significantly. Renal clearance increased, and it is suggested that the volume of distribution may increase also.

Adult↗
PubMed1987

Spectrum of bacterial pathogens in uncomplicated and complicated urinary tract infections.

The spectra of bacterial organisms of urinary tract infections (UTI) in patients with and without abnormalities in the urinary tract (complicated and uncomplicated UTIs) are compared. Data from the United Kingdom and the Federal Republic of Germany are included. In addition, the susceptibility of the pathogens to antibiotics (for oral or parenteral application) in both countries are compared. In conclusion, rational antibiotic therapy of complicated UTIs should strictly follow the antibiogram of the causative organism. For therapy of uncomplicated UTIs, the regional state of antibiotic susceptibility of the pathogens according to geographical location should be considered and kept up to date.

Escherichia coli Infections↗
PubMed1983

[Tissue concentrations of mezlocillin in prostate adenomas following intravenous bolus injections and continuous infusions].

In a total of 23 patients undergoing transurethral resection or suprapubic operation of benign hypertrophy of prostate perioperative antibiotic prophylaxis was started with 5 g of mezlocillin in each patient. In 5 patients (group I) the antibiotic was slowly (3 min) injected i.v. In 5 patients (group II) mezlocillin was administered as i.v. bolus injection of 1 g followed by i.v. infusion of 4 g during one hour. In 7 patients (group III) and in 6 patients (group IV) mezlocillin was administered as i.v. bolus injection of 1 g followed by i.v. infusion of 4 g during 4 hours. In the patients of group I-III a transurethral resection and in the patients of group IV a suprapubic prostatectomy was performed. Serum concentrations of mezlocillin were determined in intervals up to 4 hours after start of administration. The prostatic tissue concentrations were determined in both prostatic lobes in group I and group II 60 and 90 min and in group III and IV 4 hours after start of administration. In group V several tissue samples of the prostatic adenoma were obtained. The serum concentrations showed considerable interindividual variations, because the dose of antibiotic was the same in each patient and not adapted to the body weight. In group I the mean prostatic tissue concentrations at 60 min and 90 min after start of administration were 76 micrograms/g and 31 micrograms/g, respectively, in group II the mean prostatic tissue concentrations at 60 min and 90 min were 78 micrograms/g and 24 micrograms/g, respectively. In group III the mean tissue concentration at the end of the 4-hours infusion was 29 micrograms/g. In 2 patients of this group the concentrations of the 2 prostatic lobes differed considerably. In group IV measurable tissue concentrations of mezlocillin were found in 2 patients only. Considerable variations were found within the prostatic adenoma ranging from "non detectable" to approximately half of the serum concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

[Pharmacokinetics after discontinuous intravenous administration of azlocillin].

In severe, sometimes life-threatening infections azlocillin (Securopen) is administered in single doses up to 10 g in order to increase therapeutic efficacy. Therefore the serum concentrations and urinary excretion of azlocillin were investigated in 2 healthy volunteers and in 11 patients after intravenous injection (5 min) of 2 g followed by intravenous infusion of 2 g/h over 4 h. The serum concentrations increased during infusion in patients up to a median concentration of 317 mg/l. The median serum concentrations decreased down to 94 mg/l at 2 h, 43 mg/l at 4 h and 11 mg/l at 6 h after the end of infusion. 24-h urinary excretion in patients was 54.3%. Serum half-life from the last five serum concentrations (6-10 hours after start of administration) calculated amounts to a median half life of 100 min (range 60-180 min). The study showed, that using this dose and kind of administration high serum concentrations can be maintained over many hours, sufficiently high also for life threatening and difficult-to-treat infections, if administered at intervals of 12 hours.

Adult↗