Search PubMed⌕ Search

Biomedical subjects

J V Parry

Publications and source records attributed to J V Parry.

At least 91 records · Page 5Linked to original sources
PubMed1993

The testing of saliva samples for HIV-1 antibodies: reliability in a non-clinic setting.

AIMS: To assess the reliability of saliva samples as a means of testing for HIV-antibodies outside clinic settings. METHODS: Men taking part in a non-clinic longitudinal study of homosexually active men provided samples of saliva and blood. Sera were screened using a competitive ELISA (Wellcozyme) and positive sera were confirmed by an indirect ELISA (Abbott). Saliva samples were screened either using an IgG captive radioimmunoassay or an amplified ELISA. RESULTS: A total of 534 paired saliva and blood samples were tested. Overall sensitivity was 96.2% and specificity was 100%. None of the saliva tests were falsely positive for HIV-1 antibodies. CONCLUSIONS: HIV-1 saliva tests can reliably be used in a non-clinic or field setting. However, if results are to be given to respondents, it is necessary to offer adequate counselling and consider the mechanisms for referral and follow-up for those that are found to be HIV-1 antibody positive.

HIV Antibodies↗
PubMed1992

Performance assessment of neonatal dried blood spot testing for HIV antibody.

A study was undertaken to assess the performance of laboratories participating in the UK unlinked anonymised neonatal screening programme for the detection of HIV antibody. A coded panel of 100 contrived dried blood spots prepared form well characterised anti-HIV-1 and anti-HIV-2 positive sera and an anti-HIV negative serum was distributed to eight testing centres. Fifty-one out of 52 anti-HIV-1 positive samples were identified by all eight laboratories: five laboratories identified all 52 specimens. Only one laboratory detected all four anti-HIV-2 positive spots. None of the laboratories reported a seronegative spot as reactive. The sensitivity of anonymised neonatal anti-HIV-1 screening was deemed satisfactory in all participating laboratories but the margin of sensitivity was insufficient to allow pooling of dried blood spot eluates before testing. Technical modifications would be necessary to increase sensitivity for anti-HIV-2 were HIV-2 infection to be reported more frequently in the UK. Performance assessment of the screening programme should be repeated at regular intervals.

AIDS Serodiagnosis↗
PubMed1992

Application of screening and confirmatory assays for anti-HTLV-I/II in U.K. populations.

During an epidemiological study of a low risk U.K. population diverse screening and confirmatory assays for the detection of anti-HTLV-I/II were assessed. Sera from 2,900 antenatal patients were tested for anti-HTLV-I/II by gelatin particle agglutination assay (GPA). All reactive sera, and 133 randomly selected unreactive sera, were further tested by Abbott and DuPont ELISAs, "in house" competitive and IgG capture radioimmunoassays (RIAs), and Western blot (WB). Sera which reacted with any HTLV-I proteins by WB were tested by radio immunoprecipitation assays (RIPA). The two ELISAs detected all the GPA reactive specimens that were subsequently confirmed as anti-HTLV-I/II positive. Confirmation of positive screening results required the use of both WB and RIPA. Serological diagnosis of HTLV infection involves access to specialised assays that are not commercially available.

Agglutination Tests↗
PubMed1992

The detection in urine specimens of IgG and IgM antibodies to hepatitis A and hepatitis B core antigens.

The use of urine as a noninvasive specimen for the diagnosis of hepatitis A (HAV) and hepatitis B (HBV) virus infections was investigated. Specimens of urine were collected at the same time as blood or saliva specimens, or singly in cases of previously serologically confirmed recent infection. The specimens were tested for IgG and IgM anti-HAV and anti-HBc by immunoglobulin class-specific capture radioimmunoassays (GACRIA and MACRIA). On the basis of assays on urine specimens it was possible to distinguish between individuals who were susceptible or immune to HAV or who had recently been infected with HAV. Using assays on 327 corresponding saliva specimens as reference tests, the observed sensitivity and specificity of tests on urine specimens by anti-HAV GACRIA were 98.9% and 99.1%, respectively, and by anti-HAV MACRIA were 95.8% and 99.6%, respectively. IgM and IgG anti-HBc were detected readily in the urine of 35 acute or recent cases of hepatitis B but were not found in the urine of seronegative individuals. Of the urine specimens from 52 individuals who were HBsAg carriers or who had had long past HBV infections, 49 contained detectable IgG anti-HBc. Of urine specimens from 42 HBsAg carriers, 11 contained raised IgM anti-HBc levels. Urine, which is a convenient specimen to collect, can be used to study outbreaks of hepatitis A, to ascertain the HAV immune status of individuals, to differentiate hepatitis A from hepatitis B, and to identify individuals who have been naturally exposed to HBV.

Hepatitis A↗
PubMed1992

Evaluation of an enzyme immunoassay for the combined detection of antibodies to HIV-1, HIV-2, HTLV-I and HTLV-II.

OBJECTIVE: To assess the sensitivity and specificity of a newly-developed assay (Bioelisa HIV-1 + 2, HTLV-1 + 2) for the simultaneous detection of HIV-1, HIV-2, HTLV-I and HTLV-II antibodies in human serum or plasma specimens. METHODS: A panel of 775 well characterized serum or plasma samples was studied. This included samples confirmed to contain antibodies to HIV-1 (n = 46), HIV-2 (n = 19), HTLV-I (n = 49) and HTLV-II (n = 12), samples containing low titres of anti-HIV antibody (n = 14) and samples collected during HIV seroconversion (n = 36). Eighty-three sera samples which were reactive in one or more HIV or HTLV screening assays, but which could not be confirmed to contain anti-HIV-1/2 or anti-HTLV-I/II antibodies, were also examined. RESULTS: Excluding the seroconversion samples and those selected on the basis of false reactivity in other screening assays, the Bioelisa kit had a sensitivity of 100% for antibody to all four viruses and a specificity of 98.8%. The ability of the kit to detect anti-HIV during seroconversion was similar to that of several other synthetic HIV-antigen-based screening kits currently in use. CONCLUSIONS: Our findings indicate that the Bioelisa kit is sufficiently accurate to screen for both HIV and HTLV infections and that it warrants larger scale trials. Its use might allow blood donor screening for HTLV infection to be introduced more widely at modest extra cost [corrected].

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Salivary antibody testing in a school outbreak of hepatitis A.

During a community-wide outbreak of hepatitis A in Gloucester, UK there was a high attack rate in children attending two city primary schools and a pre-school centre sharing the same site. In September 1990, saliva specimens were collected from 478 (85%) of the 562 children. The prevalence of antibody to hepatitis A virus (anti-HAV), as determined by saliva testing, was 29.6%; highest prevalences were seen in 5-6-year-olds and in children from that area of the city at the centre of the community-wide outbreak. The proportion of immune children with a history of clinical hepatitis varied with age from 1 in 42.7 of under-5-year-olds to 1 in 4.7 of 8-10-year-olds. Six children who received prophylaxis with human normal immune globulin (HNIG) because they were household contacts of cases subsequently became infected. Since there was evidence of transmission outside the school environment it is unlikely that a policy of universal prophylaxis within the schools would have stopped the outbreak. Mass prophylaxis in school outbreaks is only likely to be effective if most transmission is occurring at school and if the target population can be clearly defined. Salivary antibody testing is a simple, practical and acceptable procedure in young children. Salivary antibody surveys in conjunction with vaccination against hepatitis A should provide a cost-effective method for control of future outbreaks.

Age Factors↗
PubMed1992

An outbreak of hepatitis A: school toilets as a source of transmission.

An outbreak of hepatitis A associated with a Middle school involved 23 cases; 17 were pupils attending the Middle school, one was a teacher, one was a relative of a case, and four were from the associated First school, of whom three had siblings in the Middle school. The probable source case was a male pupil infected by a sibling who had contracted hepatitis A while abroad on holiday. A questionnaire survey and salivary IgG and IgM anti-HAV testing of the pupils demonstrated a statistically significant association between infection and the use of a changing room toilet for defecation. An inspection of the school showed that toilets lacked toilet paper, soap and hand towels. Advice was given to pupils, parents and staff on hygiene. Human normal immunoglobulin was administered to susceptible family contacts, pupils and staff at the school. The school outbreak might have been prevented if the source case for the school had been given immunoglobulin when his sibling developed hepatitis A.

Child↗
PubMed1992

Detection of HIV-1 antibodies in blood specimens spotted on filter-paper.

Described are the results of an international collaborative study to evaluate the use of whole blood samples spotted on filter-paper (BSP) for the detection of antibodies to human immunodeficiency virus type 1 (HIV-1). BSP samples were collected from 40 patients at risk for HIV-1 infection and tested blindly using commercially available HIV antibody test kits, either specifically manufactured or modified for this purpose. Parallel serum samples were also collected, and the antibody reactivity was defined and confirmed by Western blot. The results demonstrate that recovery of antibodies from BSP samples after elution can be comparable to that from serum. Some kits can be easily adapted to test BSP samples, while others cannot. At present, detection of HIV antibodies in BSP samples should therefore be carried out using kits specifically manufactured for this purpose or by the development of a modified protocol using a panel of BSP and their corresponding serum specimens.

AIDS Serodiagnosis↗
PubMed1991

Determinants of HIV disease progression: six-year longitudinal study in the Edinburgh haemophilia/HIV cohort.

Markers of immune function present before infection may determine the subsequent course of disease in HIV-infected individuals. In 1983, we measured immune function in a group of haemophiliacs in Edinburgh. In 1984, 18 of these patients became infected with HIV-1 from contaminated factor VIII. We have followed-up these patients since their seroconversion. The rate of disease progression, as assessed by the appearance or not of AIDS symptoms or signs within five years of seroconversion, was related both to the concentration of total plasma IgM before exposure to infection and to the pattern of specific IgM and IgA anti-HIV response around the time of IgG seroconversion. Disease progression also correlated with concentrations of plasma interleukin-2 receptor (a marker of lymphocyte activation) and with the number and percentage of circulating DR + ve (activated) T cells. Our findings show that the extent of host immune reactivity, which may be genetically determined, is a powerful factor in the pathogenesis of HIV-associated disease.

Acquired Immunodeficiency Syndrome↗
PubMed1991

HIV-2 in the United Kingdom--a review.

Human immunodeficiency virus type 2 (HIV-2) was first recognised in 1986 and subsequently the infection was shown to be widespread in West Africa. There have been few case reports from countries outside the African continent. In North America and Europe the highest number of infections have been in Portugal and France. Twelve HIV-2 infections have been identified in the United Kingdom (UK) and nine of the twelve had some connection with Africa, mostly West Africa; in three cases only "sub-Saharan Africa" was stated on the report, and one was from Mozambique. The other three HIV-2 infections were identified as follows: one in stored sera from a man who died in 1978, one in a child from Portugal who was diagnosed in the UK as having Acquired Immune Deficiency Syndrome (AIDS) in 1985, and one in a homosexual man who was tested unlinked and anonymously in London in 1987. It is not known how many of the total number of UK HIV-2 infections are represented by these twelve, but among large numbers of blood donors and people attending genitourinary medicine clinics the occurrence of infection was rare.

AIDS Serodiagnosis↗
PubMed1991

The influence of dental status on the detection of IgG class anti-viral antibodies in human saliva.

An antibody-capture radioimmunoassay was used to measure levels of IgG class antibodies to rubella and hepatitis A viruses in serum and saliva of 30 edentulous, 30 partially dentate and 31 dentate individuals. The prevalence of seropositivity for rubella was 98.9 per cent and for hepatitis A 73.6 per cent. The serum reactivities were generally greater than those for saliva. There were 8 false-negative results for saliva out of the 182 tests performed, of which 4 were in the edentulous group, 3 in the partially dentate and 1 in the dentate group. For both rubella and hepatitis A virus antibodies the (geometric) mean ratios between the saliva and serum reactivities were similar across the three dental groups. The values for sensitivity, specificity and positive predictive value suggest that assay of saliva for antiviral IgG antibody is a satisfactory technique regardless of dental status.

Adult↗
PubMed1991

Hepatitis A outbreak involving bread.

An outbreak of hepatitis A involved more than 50 residents of a group of villages in the late spring and summer of 1989. The only food that was common to all the laboratory-confirmed cases was bread, purchased either unwrapped or as rolls, sandwiches or filled rolls, and supplied either directly from one shop or indirectly through its subsidiary outlets. It was concluded that this bread was the most likely vehicle of transmission of the hepatitis A virus and that the bread was contaminated by soiled hands which were inadequately washed because of painful skin lesions. Comprehensive control measures were successful in limiting further spread of the infection. This outbreak highlights the transmissibility of hepatitis A virus on food. The use of disposable gloves when handling food which is to be consumed without further cooking would prevent transmission of this or other infectious agents by this route.

Bread↗
PubMed1991

Prevalence of HIV, hepatitis B and associated risk behaviours in clients of a needle-exchange in central London.

In order to determine the prevalence of risk behaviour for, and antibodies to HIV and hepatitis B in clients of a needle-exchange scheme in central London we employed an anonymous, self-administered questionnaire along with salivary antibody testing by immunoglobulin (Ig) G antibody capture immunoassay. Two hundred and thirty-two subjects (193 men, 39 women; median age 32) participated; a response rate of 89%. Clients were long-term, frequent injectors. Lending used equipment at any time was reported by 55%, and borrowing by 52%. Of those who had shared needles and syringes during the last year, the majority had lent to, or borrowed from, one person only (53 and 55%, respectively). Younger clients (less than 29 years of age) reported more recent sharing than older clients (greater than 30 years of age). Five out of 211 (2.4%) samples tested for anti-HIV were positive. One hundred and eleven out of 199 (56%) samples were positive for anti-hepatitis B core (HBc). In this population of needle-exchange attenders there is no evidence of further spread of HIV, and a low prevalence of HIV infection appears to have been sustained. However, the high prevalence of anti-HBc provides evidence of previous risk behaviour and so constant vigilance is necessary if further viral spread is to be avoided. This study has established an acceptable method for the anonymous surveillance of current risk behaviour and salivary antibodies to HIV and hepatitis B virus (HBV) in a drug-using population.

Adolescent↗