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Biomedical subjects

T Midtvedt

Publications and source records attributed to T Midtvedt.

At least 181 records · Page 10Linked to original sources
PubMed1981

Effects of doxycycline on the phagocytosis of 32 P-labelled Escherichia coli by human polymorphonuclear cells.

A study on the effect of various concentrations (2-100 microgram/ml) of doxycycline on the phagocytic activity of human polymorphonuclear cells was undertaken using a radio-labelled strain of Escherichia coli as test particle. In the presence of 10% normal human serum pretreatment with 50-100 microgram/ml resulted in a 50% increase in cell-associated radioactivity. When omitting serum during the ingestion phase, or conducting the ingestion phase at 4 degree C, the ingestive capability was reduced. 2 microgram/ml present during the ingestion together with 10% normal human serum reduced the ingestive capability significantly, whereas the presence of 10 microgram/ml exerted no significant effect. By the use of 3H-labelled doxycycline the drug was shown to be firmly fixed to the leukocyte monolayer.

Doxycycline↗
PubMed1981

Studies on the phagocytic activity of human and rat polymorphonuclear cells exposed to doxycycline in vivo.

Studies are presented on the in vitro phagocytic activity of rat and human polymorphonuclear leukocytes exposed in vivo to therapeutic concentrations of doxycycline. A 32P-labelled strain of Escherichia coli served as test microbe. No significant reduction of ingestion was observed although untreated AB leukocytes tested together with serum containing doxycycline showed a nonsignificant reduction in ingestive capability (p = 0.1). A similar pattern was observed when rat polymorphonuclear cells were tested omitting serum during the ingestion phase. In the presence of serum no effects were observed. During the elimination phase (3 h) both rat and human PMN eliminated breakdown products more extensively than controls, the effect observed on human PMN being most pronounced by the use of serum containing doxycycline.

Animals↗
PubMed1981

Influence of three antimicrobial agents--penicillin, metronidazole, and doxycyclin--on the intestinal microflora of healthy humans.

Antimicrobial drugs may affect the normal gut microflora in a potentially harmful manner. The purpose of the present study was to ascertain whether any of several tests could detect drug influence on the intestinal flora of healthy subjects. Jejunal secretions and feces were cultivated aerobically and anaerobically, with measurement of fermentation gas production in tubes supplemented with glucose or lactulose; bacterial bile acid deconjugation was measured with the 14C-GCA test; and pulmonary H2 and CH4 excretion were measured with gas-solid chromatography after lactulose and glucose ingestion in 18 healthy subjects before and after peroral treatment with either penicillin, metronidazole, or doxycyclin. Bacterial numbers and fermentation gas production were unchanged after treatment, as was the bacterial bile acid deconjugating activity. Pulmonary H2 excretion after lactulose ingestion was significantly reduced after penicillin and metronidazole but not after doxycyclin treatment. Pulmonary CH4 disappeared after metronidazole but remained unchanged after penicillin and doxycyclin treatment. It is concluded that pulmonary H2 and CH4 measurement after lactulose ingestion may serve as a sensitive determinant for drug effects on the normal gut microflora.

Adult↗
PubMed1981

Intestinal and gastric bypass. Changes in intestinal microecology after surgical treatment of morbid obesity in man.

Jejunal bacterial flora, bile acid deconjugation, and breath hydrogen and methane excretion were studied in nine patients with end-to-side and nine patients with end-to-end jejunoileostomy and in eight patients with gastric bypass. Bacterial numbers did not differ significantly between healthy controls and any of the patient groups. Production of fermentation gases in anaerobic cultures supplemented with carbohydrates did not occur with jejunal secretions from healthy controls but was found in all intestinal bypass patients and half the gastric bypass patients. Bacterial bile acid deconjugation activity was significantly higher in end-to-side compared with end-to-end jejunoileostomy patients. In gastric bypass patients bile acid deconjugation was not significantly affected. Breath hydrogen after glucose ingestion was abnormal in six patients with end-to-side and three with end-to-end jejunoileostomy and in six of the patients subjected to gastric bypass. The highest values were found in the later group. Breath methane, which is found in one third of a healthy population, was absent in all 18 patients with intestinal bypass, and this may indicate that a change occurs even in the colonic microflora after this operation. Both intestinal and gastric bypass may change the small-bowel microflora, with the greatest changes occurring after end-to-side jejunoileostomy and the least changes after gastric bypass.

Adult↗
PubMed1980

Effects of some antibacterial agents on the phagocytosis of 32P-labelled Escherichia coli by human polymorphonuclear cells.

Gentamicin, trimethroprim, cephalothin, colistin, erythromycin, oxytetracycline and chloramphenicol were studied in a phagocytic system. A radiolabelled strain of E. coli was used as test bacterium and human polymorphonuclear cells were used as phagocytes. Except for trimethoprim and cephalothin, there was a tendency towards depression of the process of phagocytosis in the presence of high concentrations of the various antibiotics. Colistin in a high concentration (83 micrograms/ml) exerted the most significant effect.

Anti-Bacterial Agents↗
PubMed1979

Comparison of peritoneal macrophages from germfree and conventional mice.

Morphology, lysosomal enzyme activities, and phagocytosis via immunological receptors were tested in peritoneal macrophages from germfree and conventional mice. Nonstimulated macrophages from germfree mice showed less spreading and were more easily detached when seeded on glass than conventional macrophages. The activities of the lysosomal acid phosphatase and cathepsin D were similar in the two cell groups, whereas beta-glucuronidase showed higher activity in macrophages from germfree mice. F(c) receptor-mediated phagocytosis of opsonized sheep erythrocytes was equally effective in germfree and conventional macrophages, and both cell types attached but did not internalize erythrocytes via the C(3)b receptor. Intraperitoneal injections of mineral oil caused a significantly higher influx of macrophages in conventional mice than in germfree mice, whereas the influx of polymorphonuclear cells was enhanced in both animals. Stimulation in vivo with oil or Escherichia coli endotoxin increased cell size, spreading ability, membrane ruffling, and lysosomal enzyme activities in macrophages from both conventional and germfree mice. The Fc-mediated phagocytosis was not influenced by stimulation, whereas the capacity to internalize via C(3)b receptor was triggered in macrophages from conventional mice, but not in corresponding cells from germfree mice. Similar results were obtained after stimulation with endotoxin in vitro. Culture in fetal calf serum for 72 h caused intracellular rises in all three enzyme activities tested in macrophages from conventional mice, whereas only the activity of acid phosphatase was increased in macrophages from germfree mice. Stimulation with zymosan in vitro caused selective release of lysosomal enzyme activity in macrophages from both animal groups. We conclude that peritoneal macrophages from germfree mice share several properties with cells from conventional mice, however, unstimulated beta-glucuronidase activity was increased, whereas spreading on glass, chemotactic response, in vitro induction of lysosomal enzymes, and the capacity to internalize via the C(3)b receptor after stimulation were reduced or absent.

Acid Phosphatase↗
PubMed1979

A comparison of the in vitro activity of a new cephalosporin, cefuroxime, and cephalothin against 810 clinical isolates.

810 strains of eight species: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, Escherichia coli, Klebsiella sp, Enterobacter sp, Proteus mirabilis and Proteus vulgaris, were tested by the disc diffusion method against cephalothin and cefuroxime. The activity of the two drugs was comparable to S aureus and S epidermidis, and a little in favour of cefuroxime regarding S faecalis. Cefuroxime turned out to be superior to cephalothin against the gram negative rods investigated. This pattern was most pronounced when Enterobacter was investigated.

Bacteria↗
PubMed1979

Sensitivity patterns of bacteria and antibiotic usage at the National Hospital of Norway in 1976 and 1978.

During the first three months of 1976 and 1978 the sensitivity patterns of bacteria and the antibiotic usage at the National Hospital of Norway was recorded. The computerized results showed that bacteria isolated at the department of pediatrics was more resistant to penicillins. Isolates from two other departments did not differ very much in their sensitivity patterns. Comparing the sensitivity patterns, a tendency of increased sensitivity to antibiotics from 1976 to 1978 was seen. Exception was the increasing resistance to gentamicin. Furthermore, tobramycin was found less effective than gentamicin on our isolates. The antibiotics most widely used at the hospital are the penicillins which account for more than 50 per cent of the usage. From 1976 to 1978 the usage of antibiotics increased about 30 per cent. A more extensive use of penicillin V and G, and sulfamethoxazole/trimethoprim was responsible for most of the increase. No clear cut relationship between the antibiotic usage and the changes in sensitivity patterns of the bacteria from 1976 to 1978 was seen. Our work confirms, the usefulness of using "daily defined doses", as recommended by WHO, for estimating the antibiotic usage in a hospital.

Anti-Bacterial Agents↗
PubMed1978

Effect of rat intestinal glycoprotein on complement lytic activity of 32P-labelled Escherichia coli.

Evidence for complement activation by an intestinal glycoprotein fraction from germfree rats is presented. The lowering effect on human serum bactericidal activity of E. coli was 28% for the intestinal glycoprotein fraction, 31% for zymosan, and 25% for inulin, while the lowering effect on conventional rat serum bactericidal activity was 65%, 53% and 21%, respectively. 32P-releasing activity of serum from germfree rats and from man on labelled E. coli amounted to 8% and 28%, respectively, of the release exerted by serum from conventional rats.

Animals↗
PubMed1978

Endoscopy-related bacteremia.

A prospective study was undertaken to investigate the frequency of bacteremia after endoscopy of the gastrointestinal tract. In one out of 100 patients undergoing gastroscopy and in one out of 25 patients undergoing coloscopy, positive blood cultures could be demonstrated. In both cases anaerobe lactobacilli were recovered. No bacteremia was demonstrated in 25 patients undergoing endoscopic retrograde cholangiopancreatography (ERCP).

Cholangiography↗
PubMed1977

A glycoprotein of high molecular weight in the urine of germ-free rats.

A carbohydrate-rich glycoprotein fraction was obtained by purification of the non-dialysable material of germ-free rat urine. This procedure involved proteolytic digestion with pronase, presipitation of the acidic glycoprotein with cetyltrimethyl-ammonium bromide (CTAB), and chromatography on DEAE-Sephadex and finally on Sepharose 4B from which it was partly excluded. The purified glycoprotein contained fucose (10.1%), galactose (12.2%).N-acetylglucosamine (16.6%), N-acetylgalactosamine (19.8%), sialic acid (11.9%), and sulphate ester groups (0.7%). The amino acid content was 19%, threonine, serine and proline being the predominating amino acids. Gel electrophoresis and gel chromatography revealed a pronounced poly-dispersity of the material. Treatment of the glycoprotein with alkali in the presence of borohydride led to partial degradation of the polymer with the formation of fragments containing N-acetylgalactosaminitol. The chemical properties of the purified glycoprotein are characteristic of a mucin. The presence of this glycoprotein could not be demonstrated in conventional rat urine.

Amino Acids↗
PubMed1977

Origin of intestinal beta-glucuronidase in germfree, monocontaminated and conventional rats.

The intestinal beta-glucoronidase was studied in germfree, monocontaminated and conventional rats. The greater part of the beta-glucuronidase of the caecum and the large intestine of the contaminated animals was of bacterial origin. No bacterial beta-glucuronidase was found in the small intestine. Monocontamination with Escherichia coli gave activities corresponding to those of the conventional rats, whereas content from the caecum and the large intestine of the rats monocontaminated with Streptococcus pyogenes showed an activity approximately 10 per cent of that of the conventional rats.

Animals↗