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Biomedical subjects

A W Asscher

Publications and source records attributed to A W Asscher.

At least 37 records · Page 2Linked to original sources
PubMed1983

A rapid bioluminescence method for quantifying bacterial adhesion to polystyrene.

Bioluminescence ATP analysis has been used to assess bacterial adhesion with hydrophobic polystyrene tubes as the attachment surface. The assay was performed at 37 degrees C and pH 6.8 with a 10 min incubation period. A variation of more than 200-fold was observed in the adherence capacity of 34 urinary isolates of Escherichia coli, and organisms could be classified as strongly or weakly adherent. All strains capable of strong adhesion possessed both type 1 fimbriae and flagella, and maximum adhesion was expressed during the exponential growth phase. Attachment was in all cases virtually eliminated by addition of 2.5% (w/v) D-mannose to the incubation buffer. Conversely, strains which were deficient in type 1 fimbriae or flagella, or both, were weakly adherent during all phases of growth. There was no correlation between adherence of E. coli to polystyrene and adherence to buccal or uroepithelial cells, but there was a significant association with adherence to uromucoid (P less than 0.002).

Adenosine Triphosphate↗
PubMed1982

Glomerular filtration rate in schoolgirls with covert bacteriuria.

Clearance of technetium-99m-labelled diethylenetriaminepenta-acetic acid was used to measure total and individual kidney glomerular filtration rates in 48 girls with covert bacteriuria. The mean (+/- SD) of the total rates of 18 girls with scarred kidneys (99 +/- 24 ml/min/1.73 m2) was significantly (0.005 greater than p greater than 0.002) lower than that in 30 girls with unscarred kidneys (119 +/- 18 ml/min/1.73 m2). This reduction in glomerular filtration was related to the loss of kidney substance associated with scarring rather than to vesicoureteric reflux. The glomerular filtration rate was unrelated to the duration of bacteriuria. These findings suggest that in girls aged 4 and over neither vesicoureteric reflux nor covert bacteriuria contributes to the progression of kidney damage.

Adolescent↗
PubMed1982

Lack of adherence to epithelial cells by freshly isolated urinary pathogens.

Urinary pathogens isolated from twenty patients who had urinary tract infections (UTI) with or without symptoms were tested for adhesion to normal buccal and uroepithelial cells, and for their ability to agglutinate guinea pig and human erythrocytes. The tests were done on initial isolation and after repeated subculture in urine and nutrient broth. Of the fresh isolates all but one were non-fimbriate and all but one were non-adherent in each test system, but after subculture in broth fourteen of the twenty strains developed fimbriae and seventeen became adherent to buccal cells. Five strains remained non-adherent to uroepithelial cells despite repeated subculture, and there was no correlation between adhesion of the subcultured organisms and clinical severity of UTI. These observations suggest that adherence is not a virulence factor for bacteria once they have entered the urinary tract, and that previous claims for the existence of a correlation between the adherence properties of uropathogens and clinical severity of UTI are unfounded.

Acute Disease↗
PubMed1982

Prevention of scarring in experimental pyelonephritis in the rat by early antibiotic therapy.

Experimental pyelonephritis was produced by either retrograde or direct infection of rat kidneys by Escherichia coli 078. Combined antibiotic therapy with amoxycillin and gentamicin, commenced within 23 h of direct infection, prevented acute suppuration and subsequent scarring. The same antibiotics combination commenced 24 h after both retrograde and direct infection did not significantly reduce acute suppuration but did reduce scarring. Treatment begun later than 24 h after infection had no effect on the outcome of pyelonephritis induced by either route. Significantly lower peak levels of serum antibody to the O antigen of E. coli 078 were obtained in rats treated at 24 h after retrograde pyelonephritis than in those in which treatment was started later. Kidney scarring could not be prevented if antibiotic therapy was commenced after the appearance of mononuclear cells in the inflammatory lesion.

Animals↗
PubMed1981

Modified method for studying bacterial adhesion to isolated uroepithelial cells and uromucoid.

Several problems have been encountered with the application of published methods for the study of bacterial adherence to isolated uroepithelial cells. Of particular importance is the observation that urinary mucus traps some organisms but not others. Established techniques have been modified to overcome these difficulties and so allow a distinction to be made between adherence of bacteria to uromucoid and adherence to uroepithelial cells per se. The modified method was used to assess the ability of 34 urinary isolates of Escherichia coli to adhere to uroepithelial cells, uromucoid, or both after serial subculture in nutrient broth. The ability of the organisms to produce mannose-sensitive (MS) agglutination of guinea pig erythrocytes and mannose-resistant (MR) agglutination of human erythrocytes was tested simultaneously and taken to indicate possession of MS type 1 fimbriae andated MR fimbriae, respectively. Results revealed that only MS-positive organisms adhered to uromucoid (P less than 0.001), whereas MR-positive strains showed significantly greater attachment to uroepithelial cells than did MR-negative strains (P less than 0.05). These observations demand that published data derived from the use of a methodology in which no differentiation can be made between adherence to uromucoid and adherence to cells should be interpreted with caution.

Adhesiveness↗
PubMed1981

A four-year follow-up of schoolgirls with untreated covert bacteriuria: bacteriological aspects.

In 75 schoolgirls aged 5-11 with untreated covert coliform bacteriuria who were followed up to 4 years, infection cleared in 16 (21%), cleared and recurred in 37 (50%) and persisted in 22 (29%). Clearance of bacteriuria was significantly (P less than .05) more frequent in girls with normal radiological findings than in those with abnormal findings. In 31 (59%) of the 53 girls in whom bacteriuria cleared spontaneously, the urine became sterile within the first year after the discovery of the bacteriuria. Spontaneous clearance of bacteriuria was preceded by an increase of the sensitivity of the urinary pathogens to the cidal effect of human serum. Seven (10%) of the 75 untreated bacteriuric girls had shown progression of kidney damage (progression of scarring in 4 and failure of kidney growth in 3). In all of these 7 girls vesico-ureteric reflux (VUR) was present and bacteriuria was persistent, but in 6 of them from one to three changes in the serotype of Esch. coli or bacterial species were noted during follow-up. These observations suggest that changes in bacterial flora may be a risk factor in the progression of kidney damage in girls with urinary tract infection and VUR.

Bacteriuria↗
PubMed1979

Renal damage due to urinary tract infection.

Chronic pyelonephritis is a disease of childhood which is carried on into adult life. Children under the age of 4 in whom UTI, vesico-ureteric reflux and pyelotubular back-flow coexist appear to be particularly at risk of developing kidney damage. Attempts to prevent kidney damage in adults by detection and treatment of covert UTI are doomed to failure because persistent bacteriuria in the adult is a consequence of underlying abnormality of the urinary tract rather than its cause. Our main hope for the prevention of kidney damage associated with bacteriuria and reflux is to detect and treat these conditions at the earliest possible age.

Animals↗