Biomedical subjects
Publications and source records attributed to H McKenzie.
The clinical and epidemiological features of an outbreak of nosocomial Moraxella catarrhalis infection in a respiratory unit are described. Six isolates from five patients were shown to be indistinguishable by immunoblotting and restriction endonuclease analysis and different from 11 other, unrelated clinical strains.
Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of whole cell protein, immunoblotting with normal human serum and restriction endonuclease analysis using Taq I enzyme were applied to 38 clinically significant isolates of Moraxella (Branhamella) catarrhalis obtained during a suspected outbreak of nosocomial infection. Each of 18 strains had individual profiles by at least two of the three methods (unique strains). The remaining 20 strains were assigned to five groups (A-E) on the basis of similarity by at least two of the three methods. Isolates within groups A, D and E were homologous by all three methods. Immunoblot groups B and C had two distinct whole cell protein profiles (B1 and B2) but indistinguishable restriction endonuclease profiles (group B/C). This emphasizes the need to use more than one technique in characterizing strains from suspected outbreaks of nosocomial infection. Grouped strains were more likely to originate from the same hospital ward than unique strains and were associated with a significantly longer median time from patient admission to strain isolation (14 versus 3.5 days, p less than 0.005). Furthermore, the beta-lactamase activity was homologous within the groups. The results suggest that nosocomial infection involving several distinct Moraxella catarrhalis strains persisted over a period of months, involving at least 20 patients on three different wards. Such infection is probably common in wards harbouring suitably predisposed patients. The mode of transmission remains to be elucidated, but the above three techniques possess sufficient reproducibility and discriminatory ability to constitute suitable investigative tools.
Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins (WCP), immunoblot analysis and DNA restriction-endonuclease analysis (REA) were applied as potential typing methods to 31 clinically significant strains of Moraxella (Branhamella) catarrhalis, five of which came from a suspected outbreak of nosocomial infection in a respiratory-diseases ward. Twelve of 31 isolates were placed in four groups, each of which contained strains indistinguishable by the three typing techniques used. Each of a further two groups contained two strains, and they were similar by at least one technique; the remaining 15 strains were unique by all three methods. Four of five strains from the suspected outbreak were indistinguishable by SDS-PAGE of WCP, immunoblotting and REA. Results show that SDS-PAGE of WCP, immunoblotting and REA are suitable techniques for characterising M. catarrhalis and that there is a considerable degree of strain heterogeneity. Nosocomial infection with M. catarrhalis may be relatively common and further epidemiological studies with a combination of typing techniques are indicated.
The antigenic heterogeneity of twelve strains of Saccharomyces cerevisiae and serovar A and B strains of Candida albicans was investigated by cross-absorption of serum antibodies from a patient with Crohn's disease. On the basis of common antibody absorption patterns, eleven of the yeast strains were divided into Group 1 (five S. cerevisiae), Group 2 (two C. albicans, one S. cerevisiae) and Group 3 (three S. cerevisiae). The remaining three S. cerevisiae strains (Group 4) showed unique absorption patterns. The antigenic relationship between S. cerevisiae and C. albicans was further studied by cross-absorption of sera from eight patients with Crohn's disease. This confirmed a limited degree of cross-reaction between most strains of S. cerevisiae and C. albicans, but C. albicans serovar B significantly absorbed antibodies to more S. cerevisiae strains than did C. albicans serovar A. The results demonstrate considerable antigenic heterogeneity of S. cerevisiae and suggest that the elevated serum antibody levels to S. cerevisiae found in Crohn's disease are directed against multiple antigens.
The effect of dietary yeast on the activity of stable Crohn's disease was assessed in 19 patients. During the 1st month patients continued their usual diet (base-line period), but during the next 2 months dietary yeast was excluded except that during 1 month patients took baker's yeast capsules while for the other month they took placebo capsules. The patients' mean Pettit Crohn's disease activity index (CDAI) while taking baker's yeast (mean, 107.9; SE, 6.1) was significantly greater than during yeast exclusion (mean, 102.1; SE, 5.7; p less than 0.05). The mean of each patient's maximum CDAI during yeast exclusion (mean, 107.1; SE, 5.7) was significantly lower than those during the base-line (mean, 115.2; SE, 6.1; p less than 0.05) and baker's yeast inclusion periods (mean, 113.9; SE, 6.7; p less than 0.05). Patients with elevated yeast antibodies tended to develop a higher CDAI while receiving baker's yeast (13 of 15). These results suggest that dietary yeast may affect the activity of Crohn's disease.
IgG serum antibody was measured by ELISA in patients with Crohn's disease (15), ulcerative colitis (15), and in normal controls (15) to 12 strains of Saccharomyces cerevisiae (baker's and brewer's yeast) and to the two major serotypes of the commensal yeast Candida albicans. Antibody to 11 of the 12 strains of S cerevisiae was raised in patients with Crohn's disease but not in patients with ulcerative colitis when compared with controls (p less than 0.001). The pattern of antibody response to these 11 strains was variable, however, suggesting the likelihood of antigenic heterogeneity within the species. Antibody to C albicans was not significantly different in patient and control groups. The specificity of this unusual antibody response in Crohn's disease for S cerevisiae suggests that it is not simply the result of a generalised increase in intestinal permeability. Furthermore, because brewing and baking strains detected the response, the relevant antigen(s) are presumably common in the diet. Hypersensitivity to dietary antigens may be involved in the pathogenesis of Crohn's disease, and the role of S cerevisiae requires further investigation.
Female New Zealand White Rabbits following splenectomy (n = 9), splenectomy with 50% splenic autotransplantation (n = 8) and sham laparotomy (n = 9) have been serially exposed to type 2 Streptococcus pneumoniae and Haemophilus influenzae by aerosol inhalation. Animals were sampled for 3 weeks after exposure and the IgG and IgM type-specific antibody response measured by enzyme-linked immunosorbent assay. Haemophilus influenzae initiated a substantial anti-haemophilus IgG response which was not diminished by splenectomy. The anti-haemophilus IgM response was present in sham-operated animals, absent following splenectomy, and partially restored by splenic autotransplantation. Type 2 Streptococcus pneumoniae induced a minimal IgG and IgM antibody response in all animals irrespective of the presence or absence of a spleen. The results support the role of the spleen in mediating IgM production against polysaccharide encapsulated bacteria. The differential degree of immune response produced by the two organisms may explain in part the differential frequency with which these two organisms infect man following splenectomy.
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This case demonstrates actinomycosis in a previously unreported site, and outlines some of the difficulties encountered in diagnosing and treating this rare but unimportant condition.
An enzyme linked immunoadsorbent assay (ELISA) was used to detect IgG, IgM, and IgA antibody in urine to a crude antigenic mixture prepared from six arbitrarily chosen strains of common coliform urinary pathogens. In a group of patients with symptoms of urinary tract infection 24 of 80 (30%) urine samples were positive on culture by conventional methods, 58 of 80 (72.5%) were positive for polymorphs on microscopy, and 72 of 80 (90%) were positive for antibody by ELISA. Secretory component was detected in 28 of 80 (35%) samples, and this is consistent with local antibody production. The results show that antibody can be detected in a wide range of urine samples using a simple antigen mixture, and this may form the basis of a useful test to diagnose urinary tract infection.
The presence of two new alpha-lactalbumins has been demonstrated in the colostrum of a single mare (Equus caballus, Persian Arab). They have been designated equine alpha-lactalbumin B and C, and that isolated previously from the milk of Australian horses (English Thoroughbred) as alpha-lactalbumin A. The primary structures of B/C have been determined by automatic Edman degradation of enzymatic cleavage of the oxidized protein. Cyanogen bromide cleavage of S-carbamoyl-methylated protein provided necessary overlapping peptides. Comparison of the sequences of B and C with that of A indicates 3 and 4 amino-acid exchanges, respectively. The phylogenetic difference of equine alpha-lactalbumin B/C from bovine alpha-lactalbumin B is indicated by 39 and 40 amino-acid exchanges, respectively. The structure-function relationship, calcium binding sites and variants of alpha-lactalbumin are discussed.
Phasor admittance trajectories obtained during tympanometry and acoustic reflex measurements at 220 and 660 Hz were obtained from 67 normal ears. The distributions of natural frequency and resistance derived from these phasor trajectories provide normative data for the technique. Median values of 817 and 714 Hz for natural frequency were obtained respectively for tympanometry and acoustic reflexes. Median resistances were 139 and 555 ohms. The distributions of these parameters from tympanometry and acoustic reflexes were significantly different for both resistance and natural frequency, supporting the assumption that the two procedures measure different aspects of middle-ear vibration, which we have attributed to ossicular chain vibration and to uncoupled vibration of the tympanic membrane. Correlation data are also consistent with this assumption.
Pigeon bloom, a waxy powder which coats the feathers of racing pigeons, has been investigated as a potential antigen in pigeon fanciers' lung. Precipitins to a soluble bloom-extract were demonstrated in fifty-nine of ninety-seven people studied at two Scottish-pigeon shows, whilst precipitins to pigeon serum were found in thirty-seven. A radioimmunoassay was developed to allow an estimation of the intensity of antibody response to this antigen in nineteen pigeon fanciers being investigated for pigeon fanciers' lung. The mean antibody level to bloom extract was significantly higher (P less than 0.05) in those with acute symptoms compared to those with less severe symptoms. Pigeon bloom is a highly antigenic material and provides an alternative to pigeon droppings as a source for the inhalant antigens regularly encountered by those keeping pigeons.
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By means of a sensitive radio-immunoassay an antibody-like activity against ampicillin was detected in both IgM and IgG immunoglobulin classes of patients with infectious mononucleosis, being fifteen times the level (for IgM) and six and a half times the level (for IgG) of control subjects. Such ampicillin antibody occurred without obvious relation to prior therapy with ampicillin. This antibody which may originate in a similar manner to Paul-Bunnell antibody was nevertheless immunologically unrelated. The possibility is discussed that the ampicillin rash in infectious mononucleosis results from a disseminated reaction of the small blood vessels to circulating ampicillin-antibody complexes.
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