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Biomedical subjects

M Steinbakk

Publications and source records attributed to M Steinbakk.

28 records · Page 2Linked to original sources
PubMed1986

Influence of antibiotics on intestinal mucin in healthy subjects.

To determine the effect on microbial breakdown of intestinal mucin healthy volunteers were treated orally with ten different antibiotics. The most pronounced effects were seen after administration of bacitracin, clindamycin or vancomycin: the electrophoretic mucin pattern in faeces changed from a normal conventional pattern to a specific pattern similar to that found in germ-free rats. Disturbed patterns were also observed in some of the subjects treated with ampicillin, doxycycline, erythromycin, metronidazole or nalidixic acid. In most cases the electrophoretic mucin pattern normalized within five weeks after the end of treatment. There were no effects on the microbial breakdown of intestinal mucin in the groups treated with ofloxacin or trimethoprim/sulfamethoxazole. Thus, administration of antimicrobial drugs in clinically recommended doses may cause long-term disturbances in one microflora-associated characteristic, the breakdown of intestinal mucin.

Administration, Oral↗
PubMed1986

Influence of peroral antibiotics upon the biotransformatory activity of the intestinal microflora in healthy subjects.

The effects of ampicillin, clindamycin or metronidazole, given perorally for 6 days to eighteen healthy volunteers, upon the following intestinal microflora-associated characteristics (MACs) were evaluated: breakdown of mucin, formation of coprostanol, hydrolysis of bilirubin conjugates, formation of urobilinogen, and of some short chain fatty acids (SCFAs), presence of beta-aspartylglycine and inactivation of trypsin. Clindamycin markedly influenced the expression of all characteristics, but trypsin and beta-aspartylglycine, resulting in a pattern very much alike what has been found in germ-free animals. Ampicillin caused a significant reduction in total amount of SCFAs (P less than 0.05) and urobilinogen (P less than 0.05) present in the faecal samples. Metronidazole caused a significant reduction in the formation of coprostanol and the deconjugation of bilirubin (P less than 0.05). We conclude that orally given antibiotics may cause major alterations in several parameters reflecting the normal biotransformatory activity of the intestinal microflora, probably caused by severe disturbances in the intestinal ecosystem.

Administration, Oral↗
PubMed1986

Influence of antibiotics on the faecal excretion of bile pigments in healthy subjects.

We have evaluated the effects of 10 antibiotics, given orally for 6 days to healthy subjects, on faecal excretion of urobilinogen. Intake of bacitracin, vancomycin, clindamycin, erythromycin, and ampicillin resulted in a pronounced suppression of the faecal excretion of urobilinogen (p less than 0.05). Intake of doxycycline, metronidazole, nalidixic acid, ofloxacin, and trimethoprim/sulphamethoxazole had no significant effect. The effects of three antibiotics-ampicillin, clindamycin, and metronidazole--on faecal excretion of conjugated bilirubin were similarly evaluated. Intake of clindamycin led to a marked increase of conjugated bilirubin (p less than 0.05) in the faeces, and the pattern of separated azopigment derivatives of the bilirubin conjugates became altered. Intake of ampicillin and metronidazole resulted in far less alterations in faecal conjugated bilirubin, although a significant change was observed in the subjects receiving metronidazole (p less than 0.05). The differences between the antibiotics with regard to altered intestinal bile pigment metabolism may be due to differences in antimicrobial spectra and/or intestinal concentrations of the drugs. Our findings indicate that orally taken antibiotics may cause a suppression of the microbial deconjugation of conjugated bilirubin and urobilinogen formation, respectively. This may reflect a pronounced disturbance of the intestinal microflora.

Adult↗
PubMed1986

Influence of oral intake of seven different antibiotics on faecal short-chain fatty acid excretion in healthy subjects.

Faecal excretion of short-chain fatty acids (SCFAs) has been measured by gas chromatography in groups of six or seven healthy subjects before, during, and after they received the antibiotics bacitracin, co-trimoxazol, doxycycline, erythromycin, nalidixic acid, ofloxazin, or vancomycin orally for 6 days. Intake of bacitracin and vancomycin had pronounced effects on faecal SCFAs excretion and reduced median total concentration of SCFAs from 105.4 mmol/kg to 21.8 mmol/kg and from 69.3 mmol/kg to 19.4 mmol/kg, respectively (p less than 0.05). Erythromycin had moderate effects on the faecal SCFAs excretion, whereas small or no changes were seen during intake of co-trimoxazol, doxycycline, nalidixic acid, and ofloxacin. 2-Methylbutyric acid, a SCFA not previously seen in human faeces, was found in the faeces of all subjects (median concentration before intake of antibiotic, 1.3 mmol/kg). Bacitracin, erythromycin, nalidixic acid, and vancomycin were detected in high concentrations in faeces during therapy, whereas trimethoprim, doxycycline, and ofloxacin were found in relatively low concentrations. In conclusion, some, but not all, peroral antimicrobials induce changes in faecal SCFAs, most likely reflecting changes in the colonic ecosystem.

Administration, Oral↗
PubMed1986

Influence of ampicillin, clindamycin, and metronidazole on faecal excretion of short-chain fatty acids in healthy subjects.

The faecal excretion of short-chain fatty acids (SCFAs) has been measured in groups of six healthy subjects before, during, and after they received the antibiotics clindamycin, ampicillin, or metronidazole perorally for 6 days. Intake of clindamycin reduced the median total concentration of SCFAs from 62.9 mmol/kg faeces (wet weight) to 7.3 mmol/kg (p less than 0.05). During therapy the relative amounts of acetic acid increased from 50% to 90% of the total concentration (p less than 0.05). Ampicillin reduced the median SCFAs concentration from 62.4 mmol/kg to 47.8 mmol/kg (p less than 0.05), whereas metronidazole did not change the SCFAs concentrations significantly. The SCFAs concentrations returned to normal within 5 weeks after the treatment in all subjects. Clindamycin was detected in high concentrations in faeces during therapy. Ampicillin was detected in only one faecal sample, which was from the only subject in the ampicillin group without detectable beta-lactamase activity in faeces. Metronidazole could not be detected in faeces from any subjects receiving this drug. Clindamycin and ampicillin, but not metronidazole, induce pronounced changes in faecal SCFAs, most likely reflecting severe changes in the colonic ecosystem. An antibiotic's influence on the colonic microflora may in part depend on its antimicrobial spectrum and the concentration of antimicrobially active drug in the gut.

Administration, Oral↗
PubMed1985

Acquired immunodeficiency syndrome (AIDS). Clinical, immunological, pathological, and microbiological studies of the first case diagnosed in Norway.

The first case of acquired immunodeficiency syndrome (AIDS) in Norway, diagnosed in January 1983, is presented, with results of clinical, immunological, and microbiological studies and the results of autopsy. Immunological studies showed several immunological abnormalities, including a profound deficiency of the T-cell system of the type usually associated with AIDS. During the 11 months of symptomatic disease the patient had a series of opportunistic infections, including recurrent candida esophagitis, probable Pneumocystis carinii pneumonia, and severe and recurrent perioral Herpes simplex virus infection. During the last months he had increasing signs and symptoms of disseminated cytomegalovirus infection, which was probably the major cause of death, as revealed by autopsy. Autopsy also showed the presence of disseminated infection with a slowly growing, so far unclassified Mycobacterium species, and signs of a focal aspergillus pneumonia.

Acquired Immunodeficiency Syndrome↗
PubMed1982

Pharmacokinetics of a new, microencapsulated erythromycin base after repeated oral doses.

Pharmacokinetics of a new preparation of microencapsulated erythromycin base was studied in 16 healthy subjects. They received 250 mg base 6-hourly or 500 mg 12-hourly for 7 days. The mean maximal serum peaks (+/- SD) after morning doses on days 1, 2, 3, and 7 were 1.4 +/- 0.9, 3.2 +/- 1.1, 3.6 +/- 0.6, 3.5 +/- 1.2 mg/l after the 250-mg dose and 3.2 +/- 1.5, 3.7 +/- 2.1, 3.6 +/- 1.8, and 3.0 +/- 2.0 mg/l after the 500-mg dose. The mean 24-hour urine recoveries were 1.8 and 1.2%, the serum half-lives were (days 1-7) 1.4-2.1 h and 1.9-2.8 h for the 250-mg and 500-mg doses. The mean areas under the serum concentration curves (+/- SD) were 5.8 +/- 2.2, 11.9 +/- 2.2, and 15.3 +/- 5.1 mg . h . 1(-1) after 250 mg and 14.2 +/- 4.9, 16.4 +/- 7.6, and 14.3 +/- 9.0 mg . h . 1(-1) after 500 mg on days 1, 2, and 7. The inter- and intrasubject variability was larger after the 500-mg dose. The pharmacokinetic results indicate that both dosage alternatives are suitable and result in similar steady-state peak levels, but the initial dose should be 500 mg.

Administration, Oral↗