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Biomedical subjects

J Dankert

Publications and source records attributed to J Dankert.

At least 289 records · Page 16Linked to original sources

Protective isolation and antimicrobial decontamination in patients with high susceptibility to infection. A prospective cooperative study of gnotobiotic care in acute leukaemia patients. III: The quality of isolation and decontamination.

In a cooperative study, the quality of protective isolation and of antibiotic decontamination of the digestive tract was studied in patients with acute leukaemia by (bio)-typing of Enterobacteriaceae species, Pseudomonas aeruginosa and Staphylococcus aureus isolated from oral washings and faecal samples. These samples were collected before and during treatment of 82 patients who were either isolated and decontaminated for which latter purposes a combination of neomycin, polymyxin, bacitracin and nystatin was used (group A); isolated without decontamination (Group B) or treated on the ward without decontamination (Group C). The results indicated that protective isolation had only been completely successful during the entire (remission induction) treatment period in one of the 32 patients in Group B. In Group A patients, who underwent antibiotic decontamination in addition, successful isolation was achieved in 57% of 28 patients. Successful antibiotic decontamination of the digestive tract for the entire treatment period as far as all potentially pathogenic species are concerned, was realized in 4 (14%) of the 28 patients of Group A. Bacteriologically confirmed infections occurred in 50% of Group A patients, in 59% Group B patients and in 64% of Group C patients. It is concluded that the quality of isolation had in general been insufficient but that it was improved by oral nonabsorbable antibiotics and, furthermore, that the antibiotic decontamination procedure also requires improvement.

Adolescent↗

Antibodies against outer membrane proteins in rabbit antisera prepared against Escherichia coli O26 K60.

Antibodies directed against the protein constituents of the outer envelope membrane of Escherichia coli O26 K60 were demonstrated in antisera elicited in rabbits against three different preparations of the bacterium. Outer membraned solubilized by sodium dodecyl sulphate were applied to the antisera in an interfacial precipitin test, followed by polyacrylamide gel electrophoretic analysis of the resulting immunecomplexes. Protein profiles showed a complete outer membrane protein pattern, indicating the antigenic character of these proteins. Antisera containing antibodies against outer membrane proteins and free of reactive antibodies against lipopolysaccharide showed relatively low agglutinating activities against the bacteria. The antibodies against the protein constituents of the outer membrane belong mainly to the 7S class immunoglobulins, as indicated by 2-mercaptoethanol treatment of the antisera.

Agglutination Tests↗

Purification of specific precipitinogen and extraction of endotoxin from Haemophilus influenzae.

After purifying a Haemophilus influenzae precipitinogen from endotoxic activity by means of ultracentrifugation, column chromatography (Sepharose 6B) and ion exchange chromatography (DEAE Sephadex A25) a fraction was obtained which still contained a specific precipitinogen that was virtually free of endotoxin. Furthermore, during the chromatographic procedures fractions with a high and a low molecular weight endotoxic activity were found. The limulus lysate test was more sensitive in the high molecular weight fractions and the LD50 in mice in the low molecular weight fractions with endotoxic activity.

Animals↗

Pretreatment methods prior to gaschromatographic analysis of volatile fatty acids from faecal samples.

Vacuum distillation and steam distillation have been compared as pretreatment methods prior to the GC analysis of volatile fatty acids (VFA) in faecal material. Vacuum distillation resulted in a recovery range of 90-110% for all VFA in standard solutions. This was superior to the recovery ranges found after pretreatment by steam distillation. Coefficients of variance for steam distilled samples were higher than for vacuum distilled samples. Using a faecal homogenate, the vacuum distillation method was found to be highly reproducible. Spiking experiments substantiated the quantitative recovery of VFA from vacuum distilled samples. Modifications of the standard vacuum distillation procedure showed that care must be taken to ensure adequate cooling of the receiver tube.

Analysis of Variance↗

Gentamicin assay by enzymatic adenylylation and the application of a double osmotic shock procedure to prepare gentamicin adenine mono-nucleotide transferase.

The release of gentamicin adenine mono-nucleotide transferase (GAdT) during single cold osmotic shock treatment of E. coli K12 W677/HJR66 is not always maximal. The yield of GAdT could not be improved by using E. coli harvested at different stages of growth, by prolonging the exposure to the different steps of the shock procedure, by changing the sucrose concentration, or the magnesium chloride volume. The quantity of GAdT in osmotic extracts could be increased when a double shock procedure was performed. Using an aliquot (30 microliter) of the extract, an accurate and quick assay for gentamicin, sisomicin and tobramycin in microvolumes of serum (30 microliter) can be accomplished. To avoid high background activity in the assay, the extracts should be prepared from E. coli grown in gentamicin-free medium.

Adenosine Triphosphate↗

Bacteriological evaluation of a mobile laminar cross-flow unit for surgery, under laboratory circumstances.

A mobile laminar cross-flow unit for surgery has been evaluated by the use of an experimental bacterial aerosol of Escherichia coli in different concentrations, generated at several different sites. A separate ventilation system, mounted underneath the table, produced an almost downward directed curtain of sterile air along both sides of the table. When the velocity of the air stream, discharged by the cross-flow unit, was adjusted at 0-50 m./sec. at 2 m. from the filter face (at the head end of the operation table), the surface of the table could be maintained free of bacterial settling even after aerosolization of heavily concentrated suspensions of 10(8) bacteria/ml. at different sites outside the enclosure and underneath the table as well.

Aerosols↗

The antibacterial activity of chloroxylenol in combination with ethylenediaminetetra-acetic acid.

The bactericidal activity of RBA 777 has been found to vary with both the cultural and environmental test conditions against Pseudomonas aeruginosa and to a lesser extent against Staphylococcus aureus. These variations may explain certain anomalies in earlier work regarding the activity of chloroxylenol-based products. The addition of EDTA to RBA 777 has brought about an improvement in the performance against P. aeruginosa and this activity is confirmed in vivo. Previous reports have already illustrated this potential and the evaluations of the new antibacterial agent DA 136 confirms and extends these results to its performance under adverse conditions, often associated with the hospital environment.

Acinetobacter↗

Hepatitis B surface antigen in environmental samples from hemodialysis units.

For assessment of environmental contamination with hepatitis B surface antigen (HBS Ag), the presence of blood and of HBS Ag was determined in samples from two completely separated hemodialysis units. Samples from mucosal and skin surfaces and samples of saliva from patients were also investigated. The surfaces of both units were divided into epidemiological categories to determine the distribution of environmental contamination with HBS Ag. HBS Ag was determined by radioimmunoassay. Oral samples from all patients seropositive for HBS Ag were psoitive for HBS Ag. The rectum and the skin were positive in three instances. The presence of blood did not coincide with HBS Ag. In the unit in which HBS Ag-positive patients were treated, 4.3% of the total samples were HBS Ag-positive. Of the samples that were free of blood, 1.5% were HBS Ag-positive, whereas 18.5% of the blood-contaminated samples contained the antigen. HBS Ag-positive samples were taken from surfaces in the immediate environment of HBS Ag-positive patients, as well as from surfaces with which patients had no direct physical contact. The data lead to the conclusion that spilled blood and hemodialysis equipment are not the only sources of contamination. This fact implies that HBS Ag-positive patient undergoing hemodialysis should be completely separated from HBS Ag-negative patients.

Cross Infection↗