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Biomedical subjects

T Midtvedt

Publications and source records attributed to T Midtvedt.

At least 163 records · Page 9Linked to original sources
PubMed1984

Comparison of the in vitro activity of azlocillin and carbenicillin against 856 clinical bacterial isolates.

Eight hundred and fifty-six strains of more than ten species: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, Escherichia coli, Klebsiella spp, Proteus mirabilis, Proteus vulgaris, Enterobacter spp, Pseudomonas spp and Acinetobacter spp, were tested by the disc diffusion method against azlocillin and carbenicillin. Azlocillin was found to be superior to carbenicillin against Pseudomonas spp, and more than 90% of the tested strains had minimal inhibitory concentration (MIC) values well below the serum levels attainable after recommended doses of azlocillin. Against Enterobacteriaceae and Gram-positive cocci, however, azlocillin seemed to have little to offer.

Acinetobacter↗
PubMed1983

Demonstration of the in vitro phagocytosis of Treponema denticola by human polymorphonuclear neutrophils.

A method has been developed for the study of phagocytosis of the oral treponeme T. denticola by human polymorphonuclear neutrophils. T. denticola was labelled with 32P-orthophosphate, and phagocytosis, expressed as counts per mg cell protein, was measured after 15, 60 and 120 min of interaction between neutrophils and treponemes. Four different cell cultures were used as controls, and phagocytosis of E. coli was used as reference. The uptake of radiolabelled T. denticola was significantly larger with the PMNs than with any of the control cells. An increase of uptake was observed from 15 to 120 min. The addition of autologous human serum or rabbit T. denticola antiserum enhanced the phagocytosis 2-3 fold, and phagocytosis was decreased under an anaerobic atmosphere. Scanning electron microscopic studies also indicated that phagocytosis had taken place.

Escherichia coli↗
PubMed1983

Small-bowel bacterial overgrowth in the postgastrectomy syndrome.

Jejunal flora, bile acid deconjugation, and breath hydrogen (H2) and methane (CH4) excretion were studied in 22 Billroth II (BII)-operated patients with chronic postprandial symptoms, dumping (9), vomiting (7), pain (10), and diarrhoea (14). Sixteen were below 90% of desirable weight. Two control groups were included, one comprising 5 symptom-free, BII-operated volunteers and another comprising 12 healthy, unoperated volunteers. The numbers of bacteria recovered from jejunal secretions in the postgastrectomy patients did not differ significantly from those recovered in the symptom-free BII-operated controls but were significantly lower in the unoperated controls. Production of fermentation gas in anaerobic media supplemented with carbohydrates occurred in 17 of 22 postgastrectomy patients and in 4 of 5 BII-operated controls but in none of the unoperated controls. Bacterial bile acid deconjugating activity did not differ significantly between the postgastrectomy patients and the BII-operated controls but was significantly lower in the unoperated controls. Breath H2 excretion after glucose ingestion was significantly higher in the postgastrectomy patients than in both the BII-operated and the unoperated controls. The addition of pectin or guar gum to the glucose meal largely prevented postprandial symptoms and breath hydrogen excretion. Six out of 12 postgastrectomy patients treated with metronidazole recorded symptomatic effects, mainly on diarrhoea. Our findings indicate that jejunal bacterial overgrowth may be a major cause of the symptoms in some postgastrectomy patients. The tests available for demonstration of small-bowel bacterial overgrowth, perhaps with the exception of the glucose H2 breath test, did not differentiate satisfactorily between symptom-producing and non-symptom-producing abnormal jejunal flora. Thus these tests may seem to have a limited practical diagnostic value in such patients.

Adult↗
PubMed1983

Bacterial overgrowth in jejunal and ileal disease.

The number of bacteria recovered in anaerobic cultures of jejunal secretions was significantly higher in a group of 10 patients with jejunal disease and stagnation of gut content in the proximal small bowel than in a group of 10 patients with similar conditions in the distal ileum. Some overlap in bacterial numbers occurred between patients with jejunal disease, ileal disease, and healthy controls, whereas production of fermentation gas in anaerobic media supplemented with glucose occurred only in cultures from the patients with jejunal disease. The 14C-glycocholic acid test showed increased output of breath 14CO2 in both patient groups, whereas faecal 14C was significantly increased only in patients with ileal disease. Increased breath hydrogen excretion after glucose ingestion was recorded in 8 of 10 patients with jejunal disease only. Breath methane excretion, previously found in 44% of healthy subjects, was absent in all of 28 patients with Crohn's disease of the small, indicating that these patients have a gut flora that is different from that of the healthy population.

Adolescent↗
PubMed1983

Intestinal bypass. Bacteriological studies from different parts of the small intestine in rats.

Forty-five rats were divided into four groups according to type of operation: 1) end-to-side jejunoileal bypass (ES), 10 rats; 2) end-to-end jejunoileal bypass (EE), 10 rats; 3) jejunoileal resection (R), 10 rats; and 4) no operation, 15 rats. The luminal contents from the proximal jejunum and distal ileum, in groups 1 and 2 also from the proximal and distal part of the excluded small intestine, were examined bacteriologically 5-11 months after operation. The total number of aerobic and anaerobic microbes in the jejunum was equal in all groups. The number of aerobic bacteria in the ileum was significantly higher in the ES group than in the R and U groups. The number of bacteria capable of producing gas in glucose-supplemented media was increased both in the jejunum and ileum after ES bypass. Enterobacteriaceae and Bacteroides were commonly present in the ileum after both types of bypass but were not cultured in jejunal contents. The proximal part of the excluded intestinal segment in groups 1 and 2 contained very low numbers of microbes, whereas the flora of its distal part was similar to that of the ileum in continuity in group 1. Thus, the most marked changes of the intestinal flora occurred after ES bypass in the region of the anastomosis and distal to this.

Animals↗
PubMed1983

Detection of bilirubin conjugates in faeces of germfree rats.

The presence of bilirubin conjugates in faeces from germfree (GF) and conventional (CONV) rats was tested after using affinity chromatography and Porapak Q chromatography as clean-up procedures. The bilirubin conjugates were detected as their ethyl anthranilate azopigments after separation by thin layer chromatography (tlc). Azopigments prepared from bile of GF and CONV rats served as a reference material for the tlc analysis. After tlc of the faecal azopigment preparations it was concluded that GF rat faeces contains bilirubin conjugates, while faeces from CONV rats is devoid of conjugated bilirubin. The findings suggest that the main bilirubin conjugates present in faeces from GF rats are of the glucuronic acid type.

Animals↗
PubMed1982

Effect of human leukocyte interferon on phagocytic activity of polymorphonuclear leukocytes.

The effect of homologous leukocyte interferon HuIFN on the phagocytic activity of human polymorphonuclear (PMN) leukocytes was examined. The PMN cells were obtained from healthy donors and they were grown on coverslips. Escherichia coli labelled with 32P-orthophosphate was phagocytized in the presence of fresh homologous serum during a 15 min incubation period. PMN cells pretreated with interferon for at least 3 hours ingested more bacteria as compared to untreated controls. This effect was dose dependent, in maximal effect being obtained with 10(3) units per ml. The effect was species specific and it was neutralized by antiinterferon globulin.

Dose-Response Relationship, Drug↗
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↗
PubMed1982

Gallbladder and duodenal bacterial flora after papillotomy in rabbits.

Gallbladder and duodenal bacteria were studied in New Zealand white rabbits 1 and 4 weeks after papillotomy. The gallbladder bile was sterile in all animals before papillotomy. One and 4 weeks after papillotomy growth of both aerobic and anaerobic bacteria was found in the gallbladder bile in five of eight test animals and in none of the control rabbits. The number of bacteria in the duodenum increased in rabbits that developed growth of bacteria in the gallbladder bile after papillotomy. In the test rabbits that did not develop bacteria in the gallbladder bile and in the control group no changes in duodenal bacteria were observed.

Animals↗
PubMed1982

Sport and infection.

Infectious diseases are apparently as common among athletes as among the average population. An infection will normally lead to decreased performance, i.e. an athlete will "feel" an infection more than a non-athletic individual. Some infections are, however, more common among athletes. These are often related to the kind of athletic performance an the kind of training methods involved but can usually be prevented. In many areas there is a lack of knowledge and the need for more research is underlined.

Humans↗
PubMed1981

A study of the elimination phase of phagocytosis of 32P-labelled Escherichia coli by human polymorphonuclear cells.

A study of the elimination phase of phagocytosis of a radio-labelled strain of Escherichia coli by human polymorphonuclear cells is presented. In the presence of normal serum during the ingestion and post-ingestion phases, the elimination was 55%. Omission of normal serum during the post-ingestive phase resulted in an elimination of 35%. Without serum in both phases the elimination was approximately 50%. Microscopically the bacterial cell envelope appeared unchanged during the post-ingestive period (3h).

Escherichia coli↗
PubMed1981

Microbial conversion of bilirubin to urobilins in vitro and in vivo.

No urobilins are formed from bilirubin in germ-free rats. To isolate and investigate the strains of intestinal microorganisms responsible for this transformation, a suitable test medium was adopted. The strength of the medium and a rather high initial pH were found to be of importance. In this medium, suspensions of rat faeces and a single strain, Cl. ramosum (G62), converted bilirubin to urobilins. Cultivations of Cl. ramosum (G62) together with E. coli significantly enhanced the conversion, whereas addition of 4 other bacterial strains was without the influence. The highest in vitro formation of the urobilins was about 10% of the bilirubin present. When the 6 strains investigated in vitro were established in EXG rats, the in vivo conversion of bilirubin to urobilins was found to be about 15%, compared to 70% in CONV rats.

Animals↗
PubMed1981

Effects of antibacterial agents on the elimination of 32P-labelled Escherichia coli by human polymorphonuclear cells (PMN).

Eight antibacterial agents, cephalothin, colistin, doxycycline, erythromycin, gentamicin, chloramphenicol, oxytetracycline and trimethoprim were studied in a phagocytic system using human polymorphonuclear cells (PMN) and a radio-labelled strain of Escherichia coli as test microbe. 100 micrograms/ml of either doxycycline or trimethoprim appeared to reduce the elimination of labelled products from the PMN. The effect of doxycycline was independent of heat-labile serum factors.

Anti-Bacterial Agents↗
PubMed1981

A comparison of the in vitro activity of cefoxitin and cephalothin against 7,312 clinical isolates.

The antibacterial activity of cefoxitin and cephalothin was tested against 7,312 clinical isolates of aerobic pathogens. Cefoxitin was found to have a broad spectrum of activity. Among the gram-positive cocci, 99.1% of Staphylococcus aureus, 94.4% of Staphylococcus epidermidis and 98.1% of streptococci group B had a minimal inhibitory concentration of 16 microgram/ml or less, while only 4.6% of enterococci were sensitive to this concentration of cefoxitin. Among the gram-negative rods 94.4% of Escherichia coli, 89.3% of Klebsiella spp., 97.3% of Proteus mirabilis, 97.4% of Proteus vulgaris and 79.3% of Proteus morganii were sensitive to 16 microgram/ml of cefoxitin or less. The effect of Pseudomonas spp. and Acinetobacter calcoaceticus was negligible. Cefoxitin was less active than cephalothin against gram-positive cocci, the difference being most pronounced against enterococci. Cephalothin was also found to be more active than cefoxitin against P. mirabilis, while cefoxitin was superior to cephalothin against E. coli, Klebsiella spp., Enterobacter spp., P. vulgaris and P. morganii.

Bacteria↗