PubMed Health⌕ Search

Biomedical subjects

G W Welling

Publications and source records attributed to G W Welling.

At least 91 records · Page 5Linked to original sources
PubMed1985

The 'normalization' of germ-free rabbits with host-specific caecal microflora.

Hysterectomy-derived germ-free rabbits were given colonization-resistant caecal flora (CRF) from mice, or microflora obtained from the caecum of an antibiotic-decontaminated conventional rabbit and compared with rabbits conventionally raised with the doe. Bodyweight and the following intestinal parameters were determined for the 3 groups: colonization resistance to E. coli, relative caecal weight, villus:crypt ratio (ileum), beta-aspartylglycine (faeces), volatile fatty acids (caecum), and bile acids (faeces). Germ-free rabbits given mouse CRF-flora showed values quite different from control animals for most parameters, indicating unsuitability of mouse CRF flora to 'normalize' rabbits. In germ-free rabbits given modified (antibiotic-treated) rabbit flora, values for most parameters were intermediate between those found for the other 2 groups. This species-specific caecal flora should be improved to provide full 'normalization' of germ-free rabbits.

Animals↗
PubMed1985

Influence of temocillin on colonisation resistance and consequences for therapy.

The influence of temocillin on the colonisation resistance of the digestive tract was studied in mice, with doses ranging from 0.062 to 1 mg/day administered orally and 0.25 to 4 mg/day administered subcutaneously. The effect on the colonisation resistance was measured by the concentration of resistant bacteria (either endogenous enterococci or an exogenous strain of Enterobacter cloacae) as well as by the relative caecal weight and the appearance of beta-aspartylglycine in the caecal contents. None of these parameters indicated a decreased colonisation resistance by any of the dosages investigated, meaning that, in the mouse the drug can be used safely without an increased risk of overgrowth by resistant bacteria causing superinfections. Both systemic and oral administration of 0.25mg of temocillin/mouse/day (10 mg/kg/day) appeared to completely suppress the sensitive Gram-negative bacilli from the digestive tract within 2 days. This selective decontamination of the digestive tract in mice was the reason for a subsequent study in man. It emerged that selective decontamination with parenterally administered temocillin was possible in 7 out of 10 volunteers. The remaining 3 however, did not respond to temocillin although their faecal Gram-negative bacilli were susceptible to the drug. In none of the volunteers did the colonisation resistance appear to be affected. The consequences of the use of temocillin for either prevention or therapy of infections are discussed.

Administration, Oral↗
PubMed1985

Norfloxacin for selective decontamination: a study in human volunteers.

During five consecutive days three different dosages of 200, 400 and 800 mg norfloxacin were administered to ten healthy males. Cultures of feces and oral washings revealed that even the lowest dose was effective in eliminating gram-negative bacilli from the gi-tract within a reasonable period of time. At this dose signs of a decreased CR due to norfloxacin and measured by both overgrowth by resistant ppmo or the appearance of beta-asp-gly in feces were not seen. Treatment with 100 mg norfloxacin twice daily seems therefore suitable for SDD, at least in volunteers. However, further studies in patients should be performed.

Adult↗
PubMed1984

Isolation of detergent-extracted Sendai virus proteins by gel-filtration, ion-exchange and reversed-phase high-performance liquid chromatography and the effect on immunological activity.

Virus envelope proteins were isolated from Triton X-100 extracts of purified Sendai virions by gel-filtration, ion-exchange and reversed-phase high-performance liquid chromatography (HPLC). The fusion protein F, the matrix protein M and the tetrameric and dimeric form of the HN protein were isolated by gel-filtration HPLC with a solvent containing 0.1% sodium dodecyl sulphate. HN and F were also isolated by ion-exchange HPLC with 0.1% Triton X-100 in the eluent. Reversed-phase HPLC was performed on a C1 column with acetonitrile as the organic solvent. Especially the F1 and F2 component of the fusion protein F were obtained in pure form. The immunological activity of the proteins after HPLC was determined with an enzyme-linked immunosorbent assay (ELISA). After gel-filtration and ion-exchange HPLC, proteins still reacted with antiserum to the intact virus while proteins purified by reversed-phase HPLC did not react.

Animals↗
PubMed1984

Selective decontamination of the digestive tract with aztreonam: a study of 10 healthy volunteers.

Aztreonam, a minimally absorbable monobactam antibiotic that is active primarily against gram-negative bacilli, was given orally to 10 healthy volunteers in three regimens: 60 mg, 300 mg, and 1,500 mg daily for five days. The regimens were administered at least two weeks apart so that the flora could return to normal. Aztreonam had no effect on oropharyngeal flora cultured every other day. Fecal cultures from volunteers receiving the 300-mg regimen yielded no gram-negative bacilli after an average of 4.4 days of treatment. Administration of the highest dose gave similar results, albeit after a shorter interval (3.0 days). None of the regimens appreciably influenced total microscopic (anaerobic) bacterial counts in the feces. However, during administration of the 1,500-mg regimen, fecal counts of enterococci increased from an average of approximately 10(4)/g to greater than 10(7)/g, and fecal counts of yeasts tended to increase by the end of the five-day treatment period. Fecal concentrations of aztreonam increased as the dose increased in eight volunteers. No aztreonam was recovered from the feces of two volunteers, perhaps because of drug inactivation.

Adult↗
PubMed1984

Low dose oral tobramycin treatment for selective decontamination of the digestive tract: a study in human volunteers.

Tobramycin has been given orally to eight human volunteers for four successive days, to investigate its effect on the Gram-negative enterobacilli as well as on the endogenous anaerobic microflora. The effect was investigated in three treatment legs; i.e. in daily doses of 300 mg, in daily doses of 500 mg and thirdly in daily doses of 200 mg in combination with 1000 mg of neomycin. With 300 mg tobramycin daily, seven of eight volunteers had no Gram-negative bacilli in their faecal cultures by about four days after the onset of treatment. Their anaerobic micro-flora was slightly affected during treatment as evidenced by the appearance of low concentrations of beta-aspartylglycine in their stools. The other dose regimens were not significantly more effective in eliminating Gram-negative bacilli from the intestines; the anaerobic flora however, was more severely affected. Because evidence of induction of resistance was noticed it is recommended that if tobramycin is used for selective decontamination of the intestinal tract it should be given in combination with another antimicrobial drug such as polymyxin.

Adolescent↗
PubMed1983

Determination of beta-galactosidase activity in the intestinal tract of mice by ion-exchange high-performance liquid chromatography using epsilon-N-1-(1-deoxylactulosyl)-L-lysine as substrate.

epsilon-N-1-(1-Deoxylactulosyl)-L-lysine was synthesized and used as a substrate to assay beta-galactosidase activity. epsilon-N-1-(1-Deoxylactulosyl)-L-lysine and its degradation product epsilon-N-1-(1-deoxyfructosyl)-L-lysine were detected by high-voltage paper electrophoresis and ion-exchange high-performance liquid chromatography. The beta-galactosidase activity in different parts of the intestinal tract of germ-free and control mice was determined and compared with a beta-galactosidase activity which degrades lactose at pH 8.5 and 5.0 and which corresponded with bacterial and host enzymatic activities, respectively.

Amino Acids↗
PubMed1983

Purification of detergent-extracted Sendai virus proteins by reversed-phase high-performance liquid chromatography.

Sendai virus envelope proteins were isolated by reversed-phase high-performance liquid chromatography. The F (F1 and F2, connected by disulphide bonds), M and HN proteins were extracted from purified Sendai virions with Triton X-100. After removal of the detergent from the extract with Amberlite XAD-2 and reduction of the proteins, separation was performed on a small (10-nm) and on a larger (30-nm) pore size C18 column. Proteins were eluted with a gradient of an ethanol 1-butanol mixture in 12 mM hydrochloric acid. On the 10-nm pore size column, F2 was completely recovered in pure form, whereas the recoveries of the other proteins were low (5-25%). Similar results were obtained with the 30-nm pore size column, except for protein F1 of which the yield was higher (50%).

Amino Acids↗
PubMed1983

Isolation of Sendai virus F protein by anion-exchange high-performance liquid chromatography in the presence of Triton X-100.

Purified Sendai virions were treated with Triton X-100. The detergent extract containing the fusion protein (F) and the haemagglutinin-neuraminidase protein (HN) was subjected to anion-exchange high-performance liquid chromatography on a Mono Q (Pharmacia) column with 0.1% Triton X-100 in phosphate-buffered saline. HN was not retained by the column while elution with a salt gradient resulted in several peaks containing mainly or only F protein.

Chromatography, High Pressure Liquid↗
PubMed1983

Influence of the microbial flora on the amount of CCK8- and secretin21-27-like immunoreactivity in the intestinal tract of mice.

Determination of CCK8- and secretin21-27-like immunoreactivity in the intestinal tract of germ-free and control mice with the modified-phage assay showed that in germ-free mice as well as in control mice the highest amount of immunoreactivity is present in extracts from the small intestines. CCK8-like immunoreactivity is about 2 times higher and secretin21-27-like immunoreactivity is about 3 times lower in an extract from the small intestines of control mice than in the comparable extract of germ-free mice. The extracts from the small intestines of germ-free and control mice were applied to a Sephadex G-50 column. Higher molecular weight CCK8- and secretin21-27-like immunoreactive material was found to be present in the extract from the small intestines of control mice and virtually absent in the extract from the small intestines of germ-free mice.

Animals↗
PubMed1983

Selective decontamination of the digestive tract by pipemidic acid.

The possible use of pipemidic acid for preventing infections in granulocytopenic patients by selective elimination of the gram-negative rods from the digestive tract was evaluated. Fecal samples were collected before, during, and after therapy from 23 adults who were undergoing treatment of urinary tract infections with pipemidic acid at a dosage of 200 mg orally four times daily for 10 days. The concentration of pipemidic acid in the majority of the stool samples tested was 220 to 600 micrograms/g. However, in 19% of the samples collected on day 5, the concentration was below the detection limit (23 micrograms/ml). Approximately 90% of the fecal samples collected during or shortly after therapy were negative for members of the family Enterobacteriaceae. Resistance of the gastrointestinal tract against colonization by microorganisms from the environment (so-called colonization resistance) remained unimpaired, as measured by the absence of beta-aspartylglycine in the stool.

Adolescent↗
PubMed1982

Comparison of methods for the determination of beta-aspartylglycine in fecal supernatants of leukemic patients treated with antimicrobial agents.

Beta-Aspartylglycine is an indicator of the absence of bacterial enzymatic activity in the intestinal tract. This study describes and compares four methods--(1) dansylation with thin-layer chromatography, (2) ion-exchange chromatography, (3) thin-layer electrophoresis, (4) high-voltage paper electrophoresis--to determine the concentration of beta-aspartylglycine in fecal supernatants of leukemic patients treated with antimicrobial agents.

Anti-Bacterial Agents↗
PubMed1982

The screening of four aminoglycosides in the selective decontamination of the digestive tract in mice.

The suppressive effect of amikacin, gentamicin, tobramycin and paromomycin on the aerobic endogenous flora and on the colonization resistance of the digestive tract was tested by administering one of the antibiotics orally at five different dose levels. At a certain dose level, all antibiotics suppressed the endogenous Enterobacteriaceae species. Amikacin was particularly effective in this respect. Low doses of amikacin rapidly destroyed the colonization resistance. This resistance only remained unaffected in animals treated with tobramycin in doses that were still adequate to completely suppress the endogenous Enterobacteriaceae species. We concluded that of all the antibiotics tested in this study, only tobramycin may have a future in (clinical) application for the selective decontamination of the digestive tract. Selective decontamination can be considered an effective method for infection prevention in leukopenic patients.

Amikacin↗