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Biomedical subjects

J V Parry

Publications and source records attributed to J V Parry.

At least 109 records · Page 6Linked to original sources
PubMed1990

Preliminary report: accurate assays for anti-HIV in urine.

Untreated urine specimens from 358 patients (344 attending genito-urinary medicine clinics, 14 haemophiliacs) and 353 blood donors were tested blind by a simple IgG-capture particle-adherence test (GACPAT) and a rapid IgG-capture enzyme-linked immunosorbent assay (GACELISA) for antibody to human immunodeficiency virus (anti-HIV). All 158 urine specimens from seropositive subjects were anti-HIV positive by GACPAT and 157 of them (99.4%) were positive by GACELISA. Tests on 553 urine specimens from seronegative subjects gave two repeatable false-positive reactions by GACPAT (0.4%) and none by GACELISA. By means of a modified procedure anti-gp160 was detected by commercial western blot in the urine of 44 of 45 seropositive subjects examined. IgG-capture assays will detect anti-HIV in unconcentrated urine and so allow a diagnosis in circumstances when blood sampling is impracticable.

Blotting, Western↗
PubMed1990

Sensitivity of six commercial enzyme immunoassay kits that detect both anti-HIV-1 and anti-HIV-2.

The sensitivities of six commercial combined anti-HIV-1/anti-HIV-2 enzyme immunoassays (EIAs) were evaluated, one assay (ELAVIA) based on whole virion antigen, two assays (Abbott, Wellcozyme) based on antigens expressed from recombinant DNA, and three assays (Biochrom, IAF Biochem and Pharmacia) based on synthetic peptides as antigens. All the kits investigated performed well on a panel of 47 routine anti-HIV-1-positive specimens, but on series of anti-HIV-1-seroconversion specimens from seven plasmapheresis donors, two of the peptide assays, Biochrom and Pharmacia, performed less well than the other assays. On a panel of anti-HIV-2-positive specimens, all the assays except Biochrom detected all 33 positive sera, though the reactions of some of them in the Abbott assay were relatively weak. In deciding whether to introduce a combined assay in place of an anti-HIV-1 assay, cost, specificity, the availability of confirmatory tests and the prevalence of HIV-2 in the locality, as well as sensitivity, should be considered.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Markers of HIV infection prior to IgG antibody seropositivity.

During a 1-year period of study at two plasma collection centers, 7 of 35,000 plasma donors seroconverted to the human immunodeficiency virus (HIV) and had stored plasma samples that predated or antedated the seroconversion period. From each donor, three to eight plasma samples that had been collected at 2- to 7-day intervals were tested for IgG and IgM antibodies to HIV with enzyme immunoassays, Western blot testing, and radioimmunoprecipitation assays. The presence of an HIV viremic phase was demonstrated by the infectivity of plasma on normal, phytohemagglutinin-stimulated peripheral blood mononuclear cells and by the detection of HIV antigen. In 5 of these donors, HIV antigen was detected prior to or simultaneously with IgG to HIV; these HIV-antigen-positive samples overlapped an IgM immune response. The disappearance of detectable HIV antigen, and to a lesser extent plasma infectivity, was concurrent with the development of an IgG immune response. Although the improved sensitivity of a recombinant DNA-derived anti-HIV screening assay shortened the "window period" between initial HIV infection and antibody detection, HIV antigen and plasma HIV viremia were the only markers of HIV infection for several days in 2 donors. These results demonstrate that HIV plasma viremia and antigenemia occur prior to seroconversion in healthy plasma donors.

Adult↗
PubMed1989

Diagnosis of hepatitis A and B by testing saliva.

The use of salivary samples to diagnose acute viral hepatitis was investigated. Tests for IgM antibody to hepatitis A virus (anti-HAV) on 29 acute-phase samples from serologically confirmed cases of hepatitis A were strongly reactive. Follow-up samples indicated that IgM anti-HAV persisted at moderate levels for 2-4 months and was not usually detectable thereafter. The ratio of IgM to IgG anti-HAV (RIA index) correlated closely with the interval from onset of infection. Significant levels of IgM anti-HAV were not detected in the saliva of 103 IgG anti-HAV positive and 102 IgG anti-HAV negative individuals nor of 4 individuals with hepatitis B. Similarly, IgM anti-HBc was present in the saliva of acute cases of hepatitis B, but not in the saliva of 25 IgG anti-HBc positive and 85 IgG anti-HBc negative individuals, nor of 24 individuals with recent hepatitis A. It is concluded that saliva is a convenient and satisfactory alternative to serum for the diagnosis of hepatitis A infection.

Disease Outbreaks↗
PubMed1989

Investigation of an outbreak of hepatitis A simplified by salivary antibody testing.

In March 1988 a general practitioner notified two cases of hepatitis A in a private boarding school. Epidemiological investigation, including testing for salivary antibodies revealed a further five cases and established immunity to, and recent infection with, hepatitis A virus (HAV). The pattern of the outbreak was described. A number of practices which would encourage cross-infection were corrected. Normal human immunoglobulin was given to contacts. Repeat salivary testing 10 weeks later revealed that two more boys had become reactive for anti-HAV, though at a low titre. These may have been serological responses to HAV infection modified by the passive immunization.

Adolescent↗
PubMed1989

An immunoglobulin G antibody capture particle-adherence test (GACPAT) for antibody to HIV-1 and HTLV-I that allows economical large-scale screening.

GACPAT is a modification of a gelatin particle-agglutination test for the detection of anti-HIV-1 and anti-HTLV-I. In it, antigen-coated particles react with immunoglobulin captured from the specimens onto the surface of U-bottomed reaction wells previously coated with anti-gamma chains. In initial tests on 1127 blood donations, of 628 HIV-1 high-risk specimens and 176 HTLV-I high-risk specimens, GACPAT for anti-HIV-1 was 98.9% specific and 100% sensitive, and for anti-HTLV-I was 99.0% specific and 93.0% sensitive. It rivalled the sensitivity of second-generation enzyme-linked immunosorbent assays (ELISA) for anti-HIV-1 in tests on specimen dilutions and on seroconversion series. GACPAT can be used as a cheap, large-scale test and as a simple confirmatory check on other assays.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Evaluation of needle exchange in central London: behaviour change and anti-HIV status over one year.

From November 1987 to October 1988, numbers of clients, visits made and syringes dispensed and returned were monitored at the needle exchange of the Middlesex Hospital, London, UK. A sample of clients were interviewed 1 month after entry to the scheme and again 3 months later to evaluate changes in injecting and sexual risk behaviours for HIV infection. Clients were asked to donate saliva for anti-HIV immunoglobulin G (IgG) antibody capture radioimmunoassay (GACRIA). The rate of lending and borrowing used injecting equipment fell, both compared with rates prior to entry to the scheme and during the period of study. Frequency of injecting did not increase and there was reduced incidence of abscesses. There was a highly significant correlation between multiple sexual partners and condom use and a reduction in the proportion of clients with multiple partners. On entry to the study, seven out of 121 (6%) clients were anti-HIV positive; after 3 months, a further two clients tested were found to be anti-HIV positive. Anti-HIV positivity prevalence for the year of study was nine out of 121 (7%). The scheme attracts clients, reduces injecting-related risk for HIV infection and has high equipment return rates. Saliva testing is acceptable to clients. Continued monitoring of anti-HIV in saliva is indicated.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Rational programme for screening travellers for antibodies to hepatitis A virus.

A blood test and a saliva test for antibody to hepatitis A virus (anti HAV) were offered to British travellers seeking human normal immunoglobulin (HNIG) prophylaxis. The specimens were tested by an IgG capture and a competitive radioimmunoassay (GACRIA, COMPRIA). By GACRIA 211 subjects were anti-HAV positive and 358 anti-HAV negative on both serum and saliva. 10 other seropositive subjects had weakly positive saliva reactions. There were three discrepant results. For the population investigated HNIG use could be minimised at no extra cost by first testing the saliva of those greater than 40 years old, frequent or long-stay travellers, those born in HAV endemic areas, and those with a history of jaundice. Of the 51% of travellers tested for these reasons 20% were anti-HAV positive. They made up 76% of all those with antibody.

Antibodies, Viral↗
PubMed1988

Detection of immunoglobulin M antibody in primary human immunodeficiency virus infection.

Consecutive serum samples obtained from 20 homosexual men during symptomatic primary HIV infection were examined by a variety of IgG and IgM antibody assays. All sera obtained 2-5 weeks after onset of disease contained IgM anti-HIV as demonstrated by an IgM antibody capture assay. The IgM antibodies appeared during the 2 first weeks of illness, reached peak titres at 2-5 weeks and declined thereafter to undetectable levels at 2-3 months after the onset of disease. By contrast, IgG anti-HIV appeared later, during the second week after the onset of symptoms, and did not reach maximal levels until the IgM response had waned. The first IgM antibodies to appear were directed against gag proteins. IgM antibodies against env antigens were found less frequently and later in the course of the disease. These results suggest that IgM antibody determination may be helpful in the diagnosis of early HIV infection as a possible addition to the combined use of antigen detection and a second generation ELISA, which, in the present study, was found to be highly reliable for diagnostic purposes.

Acquired Immunodeficiency Syndrome↗