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Biomedical subjects

D H Joynson

Publications and source records attributed to D H Joynson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Five commercial enzyme linked immunosorbent assay kits for toxoplasma specific IgM antibody.

Five commercially available enzyme linked immunosorbent assay (ELISA) kits for the detection of specific IgM against Toxoplasma gondii were evaluated in a three centre study and results compared with those of the Public Health Laboratory Service ELISA for Toxoplasma IgM (PHL IgM ELISA). Fifty selected sera were tested by all the methods (Toxo-M, Captia Toxo-M EIA, Toxo Enz M EIA, Toxonostika IgM EIA, Sopazyme Toxo IgM EIA) at the three reference centres in England and Wales and 177 routine sera by all the methods in one or other of the centres. Ten of the 50 selected sera contained autoimmune antibodies but no specific IgM and 29 had toxoplasma specific IgM detectable by the PHL IgM ELISA. The kits were assessed for their specificity and sensitivity compared with the PHL IgM ELISA, and the percentage coefficient of variation for binding to the solid phases was determined. They were also rated subjectively by the staff performing the assays and an overall impression of each kit was gained by allocating scores of several criteria. There was quite close agreement among the results obtained with all five commercial assays and the PHL IgM ELISA, although some of the sera pre-selected as being potentially problematic showed the limitations of some of the assays.

Animals↗
PubMed1988

Enzyme-linked immunosorbent assays for the measurement of specific antibodies in experimentally induced ovine toxoplasmosis.

Tachyzoites of the RH strain of Toxoplasma gondii were inoculated intravenously into sheep following which serum samples were collected at approximately weekly intervals for 9 months. The sera were examined by the toxoplasma dye test and two enzyme-linked immunosorbent assays (ELISA) specifically developed for investigations of ovine toxoplasmosis. One was an antibody class capture assay for the detection of anti-toxoplasma specific IgM, the other an indirect assay which detected anti-toxoplasma IgG. Some of the sheep had antibodies to toxoplasma prior to inoculation but none had specific IgM. Sera collected 17 days after inoculation showed that all had raised specific antibody levels but the only sheep that produced specific antitoxoplasma IgM were those that were initially without any antibody. Specific IgM could be detected in all these particular sheep for at least 1 month after infection and up to 3 months in some. Specific IgG persisted at high levels for at least 3 months and could still be detected at moderate levels for at least 9 months. The ELISA methods described are simple to perform and could clearly distinguish between previous infection and this experimental infection with Toxoplasma gondii.

Animals↗
PubMed1988

Rapid indirect enzyme linked immunosorbent assay (ELISA) for detecting antitoxoplasma IgG: comparison with dye test.

A rapid and simple enzyme linked immunosorbent assay (ELISA) for the detection of specific IgG against Toxoplasma gondii was compared with the dye test on 533 serum samples. In general, results were comparable but not with sera that contained high concentrations of toxoplasma specific IgM or that had been heated at 56 degrees C. There were no false positive results with sera containing rheumatoid factor or anti-nuclear factor. It is concluded that if a dye test is not to be performed then the serum should be tested for both toxoplasma specific IgG and IgM to avoid misleading results. Heat inactivated serum should also not be tested in this type of specific IgG assay.

Animals↗
PubMed1987

Public Health Laboratory Service enzyme linked immunosorbent assay for detecting Toxoplasma specific IgM antibody.

An enzyme linked immunosorbent assay (ELISA) based on the antibody class capture method for the detection of specific IgM against Toxoplasma gondii, using the microtitre plate format, was developed. Antigen binding was detected using a monoclonal antibody, CIE3, conjugated to horseradish peroxidase. Prior mixing of the conjugate and antigen improved the stability of these reagents as well as removing an incubation stage from the assay. The incubation time of less than four hours permits a rapid throughput of specimens. Using the assay, a total of 163 sera were examined in a three centre study and good agreement was found. Results were expressed as arbitrary enzyme immunoassay units (EIUs) against a freeze dried standard. Throughout the study the standard serum showed a coefficient of variation less than 10% across the microtitre plate. By measuring IgM titres in patients having toxoplasmic lymphadenopathy with a known date of onset, IgM class antibodies were shown to peak at two months, persisting for about six months. In addition, a case of laboratory acquired toxoplasmosis was monitored. Sera shown to contain rheumatoid factor and antinuclear factor did not give false positive results. This rapid, robust, and simplified assay is used by the Public Health Laboratory Service Toxoplasma Reference Units and will provide a standard with which other assays can be compared.

Animals↗
PubMed1986

Kit systems for identifying gram negative aerobic bacilli: report of the Welsh Standing Specialist Advisory Working Group in Microbiology.

Under the auspices of the Welsh Standing Specialist Advisory Working Group in Microbiology (WMG) 10 clinical microbiology laboratories in Wales undertook a collaborative study to assess 10 commercial kits for the identification of aerobic Gram negative bacilli. In excess of 1000 such strains were examined in parallel with each kit system. Accuracy, reproducibility of accuracy, and reproducibility alone were assessed, together with the cost effectiveness of the kits used. A ranking order of kit performance based on the above variables was drawn up.

Bacteriological Techniques↗
PubMed1986

Hexetidine ('Oraldene'): a report on its antibacterial and antifungal properties on the oral flora in healthy subjects.

A randomized, double-blind crossover trial, in 10 adult healthy subjects, was carried out to compare the antibacterial and antifungal activity of a 0.1% solution of hexetidine with that of placebo. The pre-dosing oral flora of the subjects was assessed from saliva samples cultured for aerobic and anaerobic bacteria, as well as Candida albicans. Subjects then rinsed their mouths for 1 minute 3-times a day with 15 ml 0.1% hexetidine or placebo, saliva samples being collected at 2 minutes, 30 minutes, 1 hour, 3 hours and 5 hours post-dosing. Dosing was continued for 8 consecutive days on each treatment with an intervening wash-out period of 1 week. Hexetidine reduced aerobic bacterial counts on Day 1 and Day 8 by a maximum of 83% and 86%, respectively, at 2 minutes post-dosing. The reductions were statistically significantly lower than placebo up to 1 hour post-dose on Day 1 and up to 3 hours post-dose on Day 8. Similarly for anaerobic bacterial counts, 92% and 88% maximum reductions were recorded on Day 1 and Day 8, which again were significantly lower than placebo for up to 3 hours post-dose. For Candida albicans, however, the maximum reduction was 91% on the first day and 67% on Day 8, maintained for 30 minutes post-dosing. Although not eradicating completely aerobic and anaerobic bacteria, it is concluded that the substantial reduction in their numbers should prove clinically useful.

Adolescent↗
PubMed1983

Bordetella pertussis isolation in general practice: 1977-79 whooping cough epidemic in West Glamorgan.

Some of the factors influencing the isolation rate of Bordetella pertussis during a whooping cough epidemic in West Glamorgan, Wales, are reported. The organism was isolated from 39% of patients with clinical whooping cough, pernasal swabbing being much more successful than cough plates. Isolation rates were increased in the non-immunized, particularly in the first year of life. Erythromycin and co-trimoxazole significantly reduced the isolation rate of B. pertussis but this did not occur with penicillin. In this study 20% of patients were culture positive 6 weeks after the onset of their infection. It is suggested that the Department of Health and Social Security recommendation of a minimum period of three weeks exclusion of children from school is inadequate. During the epidemic, the proportion of strains of B. pertussis containing antigen 2 more than doubled.

Adult↗
PubMed1979

Water: the natural habitat of Mycobacterium kansasii?

It has been demonstrated that, after inoculation, Mycobacterium kansasii will survive in water up to 12 months without any change in cultural or lipid characteristics. The organism failed to survive in soil. It is suggested that the natural habitat of M. kansasii is water.

Mycobacterium↗
PubMed1979

Salmonella isolation from hospital areas.

Evidence of the presence of salmonellas in a paediatric ward, a special care baby unit, a maternity unit and a hospital kitchen was obtained by culture of sewer swabs, faeces and food samples. The survey was designed to cause as little administrative interference as possible. The technical aspects of the survey did not strain laboratory facilities. Minimal secondary spread of salmonella infection was experienced.

Bacteriological Techniques↗
PubMed1978

Bowls and bacteria.

An episode of nosocomial infection with Klebsiella aerogenes in a surgical ward, in which six patients were infected, is described. The cause of the outbreak was identified as being contaminated washing-bowls. It is recommended that each patient should have his own bowl, which should be disinfected after use, dried and stored upside-down.

Adult↗
PubMed1977

Role of in vitro and in vivo tests of hypersensitivity in beryllium workers.

The value of the beryllium macrophage migration inhibition (Be MIF) and Mantoux tests in the diagnosis of chronic beryllium disease and in the detection of hypersensitivity in healthy beryllium workers is demonstrated. In the absence of steroid treatment the Be MIF test is positive in chronic beryllium disease patients. Seven of 50 (14%) helathy beryllium workers were Be MIF positive, while all the control subjects, normal and sarcoidosis patients, were negative. Healthy beryllium workers tend to be more often Mantoux negative than a comparable group of non-exposed workers, and although not conclusive this finding correlates with a positive Be MIF test. Although the detection of hypersensitivity is not diagnostic of disease, the Be MIF test can be used as an additional method for monitoring the health of beryllium workers. The full significance of our results should be assessed by a long-term study.

Adult↗
PubMed1976

Observations on environmental contamination in a microbiological laboratory.

Contamination of a laboratory environment with pathogenic or non-pathogenic micro-organisms may be relevant to safety of technicians and quality of technical performance. Two widely separated incidents in 1968 and 1974 initiated a study of aspects of the laboratory environment. Water-baths, water of syneresis and portions of salmonella cultures spurting out of the sterilizing flame were examined. The water of water-baths was shown to be contaminated from the fluid cultures incubated in them. This raised questions of potential cross-contamination and reporting of false positives. Water of syneresis was sometimes contaminated with salmonellas. A few quantitative counts were made. The range of counts varied between 16 salmonellas per ml. and 13,000,000 salmonellas per ml. Five hundred portions of salmonella cultures and 571 portions of Shigella sonnei cultures which had spurted from the sterilizing flame were examined. All these samples failed to grow salmonellas or shigellas. Precautions necessary to avoid environmental contamination are briefly discussed.

Bacteria↗