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Biomedical subjects

E J Kerr

Publications and source records attributed to E J Kerr.

At least 19 recordsLinked to original sources
PubMed1988

Temporal changes in biotypes of Haemophilus influenzae isolated from patients with cystic fibrosis.

Isolates of Haemophilus influenzae obtained sequentially over a period of 2 years from 62 patients with cystic fibrosis were biotyped. Rapid changes were seen from month to month in biotypes isolated from the respiratory tract and only a few of the patients harboured the same biotype for several months. Up to four biotypes were present simultaneously, whereas even two different biotypes were found in only one of a series of 148 patients with respiratory infections but not cystic fibrosis. Colony morphology was no guide to biotype, since the same biotype may show different colony appearances on the same plate and different biotypes may show identical colony forms.

Cystic Fibrosis↗
PubMed1985

Specificity of antibodies for T sites and F sites of streptolysin O.

Antistreptolysin antibody (ASO) inhibits haemolysis of erythrocytes coated with streptolysin O (SLO), but antistreptolysin activity may also be due to the presence in sera of peptide fragments of altered beta lipoproteins. SLO-mediated haemolysis results from activity of a molecular site (the t site) distinct from that at which the SLO becomes attached to the cell (the f site), and both sites might be expected to function antigenically. Absorption studies with SLO-coated latex particles, and with SLO-coated erythrocytes in the cold, provide evidence for the existence of both classes of antibody. Results also suggest explanations for the frequent observation of false-negative and false-positive latex tests.

Antibody Specificity↗
PubMed1985

Distribution of biotypes of Haemophilus influenzae and H parainfluenzae in patients with cystic fibrosis.

One hundred and eighty eight isolates of Haemophilus influenzae and 187 isolates of H parainfluenzae from patients with cystic fibrosis, patients with respiratory infections but without cystic fibrosis, and patients with neither cystic fibrosis nor respiratory infections were biotyped. Biotype I of H influenzae were found significantly more often in patients with cystic fibrosis compared with those with normal respiratory tracts. On the other hand, biotype II strains of H influenzae were found less often in the cystic fibrosis group. Half of the biotype V strains produced beta-lactamase.

Cystic Fibrosis↗
PubMed1982

Comparison of agglutination, complement fixation and immunofluorescence tests in Campylobacter jejuni infections.

Good antibody responses usually follow infection with Campylobacter jejuni. A comparison of agglutination, complement fixation and immunofluorescence tests was done on 55 sera from 40 sporadic patients with diarrhoeal disease and positive cultures for C. jejuni. Results showed 82% positive with immunofluorescence, 62% by complement fixation but only 38% by agglutination, using two reference strains COP and MEL as antigens. Overall 90% of the 40 patients were positive by one or more serological tests. Paired sera from 15 patients showed a fourfold or greater rise in only five, confirming previous observations that antibody formation occurs early in the course of infection. Results also suggest that different test systems may be detecting antibodies of different specificities. Results confirm the value of serological tests, but further information on serotypes is required for selection of suitable reference strains.

Agglutination Tests↗
PubMed1977

A specific direct radioimmunoassay for oestriol-16alpha-glucuronide in pregnancy plasma.

A specific radioimmunoassay has been developed for measuring oestriol-16alpha glucuronide in pregnancy plasma using a highly specific antiserum. The specificity of this antiserum has been assessed by the 50% displacement method and by measuring oestriol-16alpha-glucuronide concentrations in pregnancy plasma samples, both with and without chromatography. The antiserum was found to have Ka of 1.3 X 10(10) M-1. The assay had a sensitivity of 5 pg (least quantity of oestriol-16alpha-glucuronide distinguishable from the zero point, p less than 0.05), an intra-assay variation of 6.07% and an inter-assay variation of 3.36%. The assay was used to measure plasma oestriol-16alpha-glucuronide concentrations throughout eight pregnancies, five of which were normal and three had some defined abnormality.

Cross Reactions↗
PubMed1976

Studies on antistreptolysin O activity generated in serum by microorganisms.

An antistreptolysin factor (ASF) was generated in normal human serum by the growth of Staph, aureus and Pseud, aeruginosa. Alpha toxin producing strains of the former were usually positive but activity was not restricted to such strains. Positive strains produce cholesterol esterase which was obtained from DEAE-cellulose column fractions of 18 h broth cultures. Antistreptolysin factor develops slowly in serum, being maximal between the 5th and 10th days and is associated with alterations and disappearance of beta lipoproteins on gel electrophoresis. Activity also appeared in beta lipoproteins precipitated from normal serum with dextran sulphate and redissolved in nutrient broth before inoculation with Staph, aureus. The slow appearance of antistreptolysin activity in serum appears to be due to an esterase inhibitor which is present in high concentrations in some sera. Activity is also modified by the production of a staphylococcal fraction capable of binding to the antistreptolysin factor and reducing its activity. It is suggested that antistreptolysin factor which can be demonstrated in small amounts in normal human serum represents a readily available non-specific defence mechanism capable of binding to certain bacterial products and possible to other foreign protein molecules.

Antistreptolysin↗
PubMed1976

Cholesterol esterase activity in body fluids.

Antistreptolysin O activity (greater than or equal to 200 Todd units/ml) was found in 20% of 25 ascitic fluids, 20% of 55 pleural fluids and 37-5% of 56 joint fluids. These levels are not due to antibody but to the cholesterol moiety of altered beta-lipoproteins. The activity is precipitable with 10% dextran sulphate. Incubation of mixtures of fluids with titres less than 200 and normal human serum generated eight-fold or greater rises in antistreptolysin titres. This results from the activity of cholesterol esterase in the fluid acting on the beta-lipoprotein of the serum and activity was noted in 90% of ascitic fluids, 59% of pleural fluids and 54% of joint fluids. However, mixtures showing no such rise probably also contain esterase, the failure to demonstrate antistreptolysin activity being due to equilibration of ester derived cholesterol with sub-fractions of high density and very low density lipoproteins.

Antistreptolysin↗
PubMed1975

Functional role of cholesterol in infection and autoimmunity.

Cholesterol binds to streptolysin O and related bacterial toxins. In normal serum, only a fraction of the cholesterol attached to lipoprotein is available for binding, probably as a cholesterol-peptide complex formed during catabolic breakdown of the lipoprotein. Cholesterol esterase produced by certain organisms--e.g., Staphylococcus pyogenes and Pseudomonas oeruginosa--augments this fraction both in vitro and in vivo. Endogenous esterase similarly increases the amount of cholesterol-peptide complex, a mechanism which may be activated as a feedback process following binding of toxin to the cholesterol component of the complex. These complexes will thus supply a readily available means of binding bacterial toxins before antibody formation begins; Cholesterol-peptide complexes, either alone or modified by binding to toxin, may function as autoantigens. It is postulated that immune complexes so formed may be involved in atherosclerosis either by directly damaging vessels walls or by cross-reaction of antibody with cell-membrane-bound lipoproteins which equilibrate with plasma-lipoproteins.

Antibodies, Bacterial↗
PubMed1975

Partial characterisation of an inhibitor of streptolysin O produced by bacterial growth in serum.

An inhibitor of streptolysin O is generated in human and animal sera by the growth of certain organisms. The ability to do this occurs most often in Pseudomonas aeruginosa and Staphylococcus aureus (in 90% and 86% of strains respectively), but in only 32% of Staph. epidermidis strains. The inhibitor is not formed in broth. The effect appears slowly on incubation, with maximum activity after 4-7 days. Evidence suggests that two enzymes are involved, an esterase which splits ester-bound cholesterol and a proteolytic enzyme which partially hydrolyses lipoprotein, resulting in cholesterol remaining attached to protein or polypeptide fractions but with some alteration of its spatial configuration such that it is now capable of attaching to streptolysin O. The inhibitory factor appears to prevent streptolysin becoming attached to cholesterol receptor sites on the erythrocyte membrane. Removal of the precursor from serum with magnesium carbonate suggests that low-density lipoproteins may be the precursor of the inhibitor.

Albumins↗
PubMed1974

Clinical evaluation of the macrophage electrophoretic mobility test for cancer.

Experience with the macrophage electrophoretic mobility (MEM) test of Field and Caspary in subjects with malignant and non-malignant disease is reported. There was some discrimination between groups of patients with benign and malignant lesions but there was no clear separation between the groups. A trial of the Cardiff modification of the test failed to discriminate between groups of patients with benign and malignant chest disease. In the view of the authors the MEM test in its present form is not sufficiently reproducible to warrant more general clinical application as an in vitro test for cancer.

Breast Neoplasms↗