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Biomedical subjects

M R Evans

Publications and source records attributed to M R Evans.

At least 73 records · Page 4Linked to original sources
PubMed1995

Is tuberculosis taken seriously in the United Kingdom?

Tuberculosis has been the subject of much concern in recent years. Notifications have increased, inadequacies in surveillance revealed, and policies for BCG immunisation and screening of immigrants questioned. Until recently the disease was given low priority in the United Kingdom. There is no overall strategic framework for tackling tuberculosis, and fears have been expressed about the future of local tuberculosis control programmes in the new market economy of the NHS. An action plan for tuberculosis within the context of a national programme is urgently required. Only then will a major impact on the incidence of the disease be seen.

Communicable Disease Control↗
PubMed1995

Reasons for non-uptake of measles, mumps, and rubella catch up immunisation in a measles epidemic and side effects of the vaccine.

OBJECTIVE: To investigate the reasons for poor uptake of immunisation (non-immunisation) and the possible side effects of measles, mumps, and rubella vaccine in a catch up immunisation campaign during a community outbreak of measles. DESIGN: Descriptive study of reasons for non-immunisation and retrospective cohort study of side effects of the vaccine. SETTING: Secondary schools in South Glamorgan. SUBJECTS: Random cluster sample of the parents of 500 children targeted but not immunised and a randomised sample of 2866 of the children targeted. MAIN OUTCOME MEASURES: Reasons for non-immunisation; symptoms among immunised and non-immunised children. RESULTS: Immunisation coverage of the campaign was only 43.4% (7633/17,595). The practical problems experienced included non-return of consent forms (6698/17,595), refusal of immunisation (2061/10,897 forms returned), and absence from school on day of immunisation (1203/8836 children with consent for immunisation). The most common reasons cited for non-immunisation were previous measles infection (145/232), previous immunisation against measles (78/232), and concern about side effects (55/232). Symptoms were equally common among immunised and non-immunised subjects. However, significantly more immunised boys than non-immunised boys reported fever (relative risk 2.31 (95% confidence interval 1.36 to 3.93)), rash (2.00 (1.10 to 3.64), joint symptoms (1.58; 1.05 to 2.38), and headache (1.31 (1.04 to 1.65)). CONCLUSIONS: Many of the objections raised by parents could be overcome by emphasising that primary immunisation does not necessarily confer immunity and that diagnosis of measles is unreliable. Measles, mumps, and rubella vaccine is safe in children aged 11-15.

Adolescent↗
PubMed1995

The detection of HIV-1 proviral DNA by PCR in clotted blood specimens.

Six hundred and ninety-two specimens, each consisting of a suspension of the residual free cells in samples of clotted blood (but not the clots themselves) from 680 patients at high risk for exposure to human immunodeficiency virus (HIV), were tested by a nested polymerase chain reaction (PCR) procedure which had been optimized to give a sensitivity of detection of one copy of HIV-1 proviral plasmid DNA, and the results were compared to those of testing for antibody to HIV on the same specimens. Fifty-one of the specimens were positive for antibody to HIV and 49 of these were also positive by the PCR; the two samples which gave discordant results were found to be PCR-positive when the test was repeated on DNA extracted from the clots themselves. Two specimens were found to be negative for antibody to HIV but were positive by the PCR (53 positive specimens in all). Direct sequencing of the PCR DNA products confirmed their specificity in all cases and demonstrated that no two patients gave the same predicted amino acid sequence for the V3 loop region. The sequences revealed both European/North American and African motifs at the crown of the V3 loop thus indicating a diversity of HIV strains in the SW Thames Region of South London. The results show that the confirmatory PCR for HIV-1 can be carried out efficiently on the same clotted blood specimens as used for routine HIV serology on patients undergoing diagnostic evaluation.

Africa↗
PubMed1995

Cytomegalovirus viraemia in HIV infection: association with intercurrent infection.

The aim of this retrospective study was to investigate the clinical significance of cytomegalovirus (CMV) viraemia in HIV-infected subjects (with or without AIDS) who had attended this hospital during a 45 month period. They were reviewed regularly and, when clinically indicated, tested for CMV viraemia. The blood of 105 subjects was cultured for CMV and 34 had at least one episode of CMV viraemia during the review period. The viraemia was present during CMV disease in nine of the 34 positive patients and was the only detectable infection in another two. In the remaining 23 patients, CMV viraemia occurred in association with intercurrent opportunistic infection. Among these 23 patients, the viraemia resolved in 12 after treatment (or natural resolution) of the intercurrent infection and only one of these 12 developed CMV disease (mean review period: 8 months). In another seven patients, CMV viraemia persisted despite treatment (or natural resolution) of the intercurrent infection and four subsequently developed CMV disease (mean review period: 4 months) (P = 0.08, Fisher's exact test). From the remaining four patients, no specimens for CMV culture were obtained after treatment of the intercurrent infection. The CD4 count was higher in the 12 patients in whom there was resolution of the viraemia [mean CD4 60 x 10(6)/l] compared with the seven in whom the viraemia persisted [mean CD4 45 x 10(6)/l]. These findings suggest that in some HIV-positive patients, CMV viraemia was potentiated by intercurrent infection with another micro-organism and that its treatment was sufficient to mitigate the CMV disease.

AIDS-Related Opportunistic Infections↗
PubMed1995

Salmonella outbreak from microwave cooked food.

Following a buffet meal served to six guests at a private domestic function, five of the guests and the host developed symptoms of food poisoning. Salmonella enteritidis phage type 4 (PT4) was isolated from all four individuals who submitted faecal samples for investigation. Leftover samples of a savoury rice dish consumed by all six ill persons contained 6 x 10(3)/gm Salmonella enteritidis PT4. The rice salad comprised boiled rice, raw carrots, eggs, cheese and curry powder. The curry powder and remainder of the pack of six eggs were negative on microbiological analysis. The rice dish had been prepared by heating in a 500 W microwave oven with a rotating turntable on full power for 5 min. Although the hazards of inadequate microwave cooking are well recognized, this is only the second outbreak of food poisoning from microwave cooking to be reported.

Adult↗
PubMed1995

How complete is influenza immunization coverage? A study in 75 nursing and residential homes for elderly people.

BACKGROUND: Elderly people in residential accommodation are particularly susceptible to outbreaks of influenza. Up to 70% of residents can become ill and many will develop complications or die. Immunization can prevent such outbreaks and is cost-effective. AIM: A study was undertaken to measure influenza immunization coverage in residential accommodation for elderly people and to identify factors that might influence uptake. METHOD: In March 1992, a questionnaire survey was conducted of all 113 registered nursing and residential homes for elderly people, in South Glamorgan. It asked about the demographic characteristics of people resident on 1 October 1991, their influenza immunization history and the homes' arrangements for administering immunizations. RESULTS: Questionnaires were returned by respondents from 75 homes (66%). Mean influenza vaccine uptake was 67%. Uptake was higher in nursing homes (mean of 82% in eight nursing homes) than in homes registered as both nursing and residential homes (mean of 76% in six homes) or in residential homes (mean of 65% in 61 homes). Nearly all of those immunized (94%) had been immunized by the end of November 1991. Residents who were reported to have underlying disease that increased their risk of complications if they contracted influenza were no more likely to have been immunized than those without risk factors. Immunization coverage varied considerably both between homes and between general practices. Most general practices in South Glamorgan had several elderly people in residential accommodation on their list, but only nine out of 64 practices had immunized all the elderly residents on their list and 12 practices had immunized fewer than half. Routine recording of immunization status in nursing and residential homes was variable, often as a consequence of poor communication between the primary health care team and staff at the home. Even where recorded, retrieval of the data was sometimes a problem. CONCLUSION: Influenza immunization coverage could be improved if general practices held a case register of all at-risk patients including elderly residents, and if nursing and residential homes were encouraged to keep better immunization records. These measures would facilitate year-on-year monitoring of influenza immunization coverage and the targeting of homes with low immunization coverage.

Adult↗
PubMed1994

The Southern blot. An update.

This article is devoted to the recent advances made in the Southern blotting technique, which is used for the detection of gel-fractionated DNA molecules following transfer to a membrane. The latest practical improvements made to the techniques of Southern blotting, probe labeling, and hybridization are discussed. Among the most significant advances are: new membranes, transfer methods, probe labeling, and rapid hybridization. Detailed protocols show the application of these improvements in this widely used technique.

Biotechnology↗
PubMed1994

Immune response following oral administration of cholera toxin B subunit to HIV-1-infected UK and Kenyan subjects.

OBJECTIVE: To determine the effect of HIV-1 infection on immunoglobulin (Ig) G and IgA antibody response and circulating antibody forming cell response to oral immunization with the B subunit of cholera toxin. DESIGN: Healthy UK volunteers, and HIV-1-positive UK and Kenyan volunteers at different clinical stages of HIV-1 infection received two oral immunizations. CD4+ T cells, serum beta 2-microglobulin and neopterin were measured as surrogate markers of disease stage, and correlated with immunization response. METHODS: Serum antitoxin IgG and IgA measured by enzyme-linked immunosorbent assay and antitoxin IgG, IgA and IgM antibody-forming cells detected by enzyme-linked immunospot assay at different times after two oral immunizations. RESULTS: UK HIV-positive volunteers (mean CD4+ T cell count, 52 x 10(6)/l) responded poorly to primary and booster immunization. HIV-infected Kenyans (752 x 10(6)/l CD4+ T cells) had a significant primary and booster antibody response, whereas those with a mean CD4+ T cell count 186 x 10(6)/l had an insignificant primary, but significant booster response. Two oral immunizations induced antibody responses in HIV-positive Kenyan groups (who may have prior immunity from exposure to environmental bacterial toxins) of similar or greater magnitude to healthy UK volunteers. CONCLUSIONS: Mucosal immunization may recall immune memory and be of benefit in early and moderately advanced clinical HIV disease. The findings have important clinical implications in that mucosally targeted vaccines are potentially useful in this group of patients.

Administration, Oral↗
PubMed1993

Dose-response in an outbreak of non-bacterial food poisoning traced to a mixed seafood cocktail.

An outbreak of non-bacterial food poisoning presumed due to small round, structured viruses (SRSV) occurred at a national conference. A detailed postal survey of all conference attenders was carried out to ascertain the cause of the outbreak and 355 questionnaires were returned. Univariate analysis showed that mussels in the seafood cocktail were the likely vehicle of infection. A dose-response relationship between the amount of seafood cocktail consumed and the risk of illness was demonstrated. Dose-response has not previously been documented in a food-borne outbreak due to small round structured virus. Detailed quantitative food histories can be useful in eliciting dose-response relationships and may be crucial in establishing the vehicle of infection when investigating food poisoning following consumption of a set-menu meal. Their use should be considered in other outbreak situations.

Disease Outbreaks↗
PubMed1992

Audit of a tuberculosis contact tracing clinic.

OBJECTIVE: To determine the efficiency of tuberculosis contact tracing in South Glamorgan 1987-9. DESIGN: Review of records of contact tracing clinic and of data from the Mycobacterium Reference Unit. The clinic's practice was compared with 1983 British Thoracic Society's recommendations. SETTING: Health authority tuberculosis control programme. MAIN OUTCOME MEASURES: Proportion of contacts screened, follow up attendance rates, number of secondary cases detected, and quality of record keeping. RESULTS: 101 index patients and 611 contacts were identified. 596 (97.5%) contacts were screened, of whom 139 should not have been. Of 356 contacts requiring a Heaf test, 237 were tested, seven refused the test, and 112 had chest radiography without a Heaf test. 95 contacts were unnecessarily tested. 87 contacts had chest radiography unnecessarily and seven should have had radiography but did not. 34 contacts were given follow up appointments inappropriately and seven were overlooked for follow up. Tuberculosis was diagnosed in five asymptomatic contacts, all at initial screening and all close contacts of index patients with pulmonary disease. CONCLUSION: Inadequacy of data, non-adherence to contact tracing guidelines, and failure to define the term highly infectious index case resulted in many contacts being unnecessarily screened or followed up. IMPLICATIONS: The efficiency of tracing contacts would be improved by specifying smear results and ethnic origin of the index case on the notification form, clearly classifying contacts as close or causal, and clearly defining the term highly infectious.

Adult↗
PubMed1992

Tuberculosis contact tracing: are the British Thoracic Society guidelines still appropriate?

The value of contact tracing in South Glamorgan for the period May 1987 to December 1989 was assessed. Tuberculosis was diagnosed in six (3.5%) of 170 close contacts. All were young and were detected in the initial screening. Tuberculosis was not found among 441 casual contacts. The value of follow up of contacts after the initial screening and of screening casual contacts in districts with a low prevalence of tuberculosis is questioned.

Contact Tracing↗