PubMed Health⌕ Search

Biomedical subjects

M J Harber

Publications and source records attributed to M J Harber.

16 recordsLinked to original sources
PubMed1988

Pseudomonas aeruginosa and long-term indwelling bladder catheters.

The ability of urinary isolates of nine species of bacteria to bind to urinary catheters has been assessed using a bioluminescence technique. The experiments revealed the particularly adherent properties of Pseudomonas aeruginosa. This organism has also been shown to be most frequently isolated from the urines of the patients undergoing indwelling catheterization. It is suggested that P. aeruginosa commonly grows on the surface of catheters in situ, and that at this site it can survive antibiotic therapy and cause apparent recurrence of infection by reinoculation of the urine once therapy has been completed.

Bacterial Adhesion↗
PubMed1986

Factors affecting the measurement of chemiluminescence in stimulated human polymorphonuclear leucocytes.

Optimum conditions were established for the generation and measurement of luminol-dependent chemiluminescence (CL) in human polymorphonuclear leucocytes (PMNL) stimulated with a variety of particulate and soluble agents. Several factors had a particular influence on the kinetics of CL stimulated by the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP). Two peaks, both azide-sensitive, were observed at 21 degrees C and 25 degrees C, but these increased in magnitude and merged to give a single, early peak when the temperature was increased at 37 degrees C. Pre-exposure of PMNL to a buffer containing calcium was essential for the expression of both phases of fMLP-stimulated CL, while the second peak decreased dramatically if the cells were stored at 4 degrees C for 4 hours before assay. In contrast, storage of PMNL at 4 degrees C for up to 8 hours in a buffer without divalent cations did not alter the kinetics or magnitude of CL induced by other stimuli, and had the benefit of minimizing the rate of cell aggregation. This study confirms that measurement of luminol-dependent CL in stimulated PMNL is a useful analytical tool, but shows that careful attention to experimental design is required to ensure that the observed CL provides a true measure of the parameter under investigation.

Humans↗
PubMed1986

Analysis of polymorphonuclear leukocyte respiratory burst activity in uremic patients using whole-blood chemiluminescence.

The respiratory burst activity of peripheral leukocytes from 17 patients with chronic renal failure and 12 healthy individuals was assessed using the technique of whole-blood chemiluminescence (CL). Luminol- and lucigenin-dependent CL was measured in two dilutions of venous blood following stimulation with serum-treated zymosan or phorbol myristate acetate, and the CL peaks associated with a polymorphonuclear leukocyte count of 10(4)/ml were calculated. The mean CL peaks for the patients were significantly higher than those for the controls in all experimental designs (p less than 0.05). This enhanced leukocyte respiratory burst activity was not associated with the underlying renal abnormality or with the type of dialysis treatment, but may have been related to the induction of tissue enzymes which is known to occur in uremia.

Acridines↗
PubMed1986

Activation of human polymorphonuclear leucocytes by particulate zymosan is related to both its major carbohydrate components: glucan and mannan.

Unopsonized particulate zymosan and its major carbohydrate component glucan were phagocytosed under serum-free conditions by adherent polymorphonuclear leucocytes (PMN) in a dose- and time-dependent manner. Preincubation of PMN monolayers with mannan did not cause a reduction in the phagocytosis of either particle. The phagocytic response was inhibited by preincubation of the cells with trypsin at a concentration that did not inhibit the phagocytosis of sheep erythrocytes coated with IgG or of latex particles. Homology of the recognition mechanisms for glucan and zymosan was confirmed when cells cultured on fixed glucan or on fixed zymosan failed to ingest either particle to more than 40% of control phagocytosis. Similarly, zymosan and glucan activated PMN in suspension, in a dose- and time-dependent manner, to generate reactive oxygen species which were measured as luminol-dependent chemiluminescence (CL). There was, however, a four-fold greater CL response to zymosan. Preincubation of PMN with mannan resulted in a significantly decreased CL response to zymosan, while the response to glucan was unaffected. The CL response was also sensitive to a range of concentrations of trypsin. In contrast, two other complex polysaccharide particles (barley-derived beta-glucan and algae-derived laminarin) were not phagocytosed by PMN, nor did they cause the generation of CL, despite the fact that they possessed the capacity, in common with zymosan and glucan, to activate the alternative pathway of complement. The identification of a trypsin-sensitive recognition mechanism on the surface of human PMN for unopsonized zymosan and glucan represents a response not hitherto characterized. Furthermore, our data indicate that the phagocytosis of unopsonized zymosan by human PMN is dependent primarily on its glucan content, but that its capacity to activate the respiratory burst may involve mannan and the recruitment of a second cell surface recognition mechanism.

Complement Activation↗
PubMed1985

Bacterial adherence.

Explore the source record for details and available documents.

Adhesins, Escherichia coli↗
PubMed1984

Effect of glomerular basement membrane on the initiation of chemiluminescence and lysosomal enzyme release in human polymorphonuclear leucocytes: an in vitro model of glomerular disease.

The effect of glomerular basement membrane (GBM) on the stimulation of human polymorphonuclear leucocytes (PMNL) was investigated using the technique of chemiluminescence (CL). GBM, in the absence of serum, did not initiate CL of PMNL and neither did GBM preincubated with fresh human or rabbit serum. In contrast, GBM preincubated with rabbit anti-human GBM serum (anti-GBM), and then thoroughly washed, initiated an immediate and marked CL response. Heat inactivation of the anti-GBM only partially reduced the CL, suggesting that both Fc and C3b receptors on the PMNL were involved. The addition of fresh, but not heat-inactivated, human serum to PMNL incubated with untreated GBM resulted in a CL response after a short lag. Subsequent analysis of the serum by electrophoresis and immunofixation indicated that the GBM had activated complement. GBM preincubated with anti-GBM was found to elicit the selective release of lysosomal enzymes from PMNL, one of these enzymes degrading the collagen moiety of the GBM. Preincubation of GBM with the serum from a patient with Goodpasture's syndrome also initiated a CL response and a selective release of lysosomal enzymes from PMNL. These results provide additional evidence for imputing a role for PMNL in the pathogenesis of glomerulonephritis. Furthermore, the technique offers a useful in vitro model for the study of immunologically mediated glomerular disease.

Anti-Glomerular Basement Membrane Disease↗
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

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↗
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↗
PubMed1975

The plasma half-life of antipyrine in chromic uraemic and normal subjects.

1. Antipyrine was given intravenously in a dose of 18 mg/kg body weight to twelve patients with chronic renal failure (plasma creatinine greater than 4.9 mg/100 ml) who were not taking drugs and twenty normal subjects. 2. Plasma antipyrine levels were measured by a specific method, the plasma half-life of the drug was determined and used as an index of drug oxidation. 3. The mean (+/- s.d) plasma antipyrine half-life in patients with chronic renal failure (7.3 +/- 2.0 h) was significantly shorter than in normal subjects (13.2 +/- 4.3 h: P less than 0.002). There was no difference in the apparent volume of distribution of antipyrine between the two groups (P greater than 0.6). 4. Pretreatment of five patients with chronic renal failure and seven normal subjects with antipyrine or phenobarbitone for weeks significantly shortened the mean plasma antipyrine half-life from 7.4 +/- 2.5 h to 5.0 +/- 1.5 h in uraemics (P less than 0.005) and from 13.2 +/- 4.5 h to 6.9 +/- 1.5 h in normal subjects (P less than 0.0025).5. These results suggest that oxidation of antipyrine by hepatic microsomal enzymes is increased in patients with chronic renal failure, but a state of maximal induction of these enzymes was not observed. The clinical implication of this finding with regard to the association between liver microsomal enzyme induction and vitamin D resistant osteomalacia is discussed.

Administration, Oral↗