PubMed Health⌕ Search

Biomedical subjects

A L Cunningham

Publications and source records attributed to A L Cunningham.

At least 91 records · Page 5Linked to original sources
PubMed1994

HIV infection of placental macrophages: their potential role in vertical transmission.

Placental macrophages were isolated and cultured in vitro to investigate their susceptibility to HIV infection and possible role in vertical transmission of HIV. After 10 days of in vitro culture the cells were positive for nonspecific esterase and acid phosphatase and negative for myeloperoxidase and placental alkaline phosphatase. They expressed cell surface HLA-ABC, HLA-DR, CD45, as well as CD68 intracellularly, as detected by flow cytometry, confirming their macrophage lineage. Approximately 80% of cells expressed surface CD14. CD4 antigen was expressed at very low levels and was confirmed by antibody blocking experiments. Infection of placental macrophage cultures with HIV resulted in a transient peak of viral replication 3 to 7 days after infection, but no later rise in HIV was detected with culture of up to 60 days. HIV replication was not up-regulated by coculture with phytohemagglutinin-stimulated lymphocytes or by treating infected cultures with tumor necrosis factor alpha or granulocyte-macrophage colony-stimulating factor.

Acid Phosphatase↗
PubMed1994

Sulfated polyanions prevent HIV infection of lymphocytes by disruption of the CD4-gp120 interaction, but do not inhibit monocyte infection.

Sulfated polyanions (SPs) bind variably to lymphocyte-expressed CD4 and inhibit binding of monoclonal antibodies to the first two domains of CD4. To further define this interaction, soluble recombinant CD4 (sCD4; four extracellular domains), its truncated amino-terminal two-domain derivative, and three linear peptide analogues spanning residues 6-60 (6-24, 20-40, 41-60) in the first domain were investigated for SP binding. Dextran sulfate (DXS) (500 kDa), polyvinyl sulfate, fucoidan, and carrageenan-kappa, each immobilized on carboxymethyl cellulose fibers, bound strongly to both the two-domain and four-domain recombinant CD4 molecules (similar to that observed with native CD4), whereas dextran sulfate (5 kDa), chondroitin 6-sulfate, and pentosan sulfate bound relatively poorly. No peptide binding to SPs was observed. Recombinant gp120 bound poorly (< 10%) to all of the immobilized polyanions, except pentosan sulfate (17%), for which some binding was noted. Binding of radiolabeled V3 loop peptide to SPs was slightly greater, with 20-30% binding to polyvinyl sulfate, dextran sulfate (500 kDa), and pentosan sulfate. Competitive binding studies demonstrated the predominance of sCD4 rather than rgp120 binding to SPs and supported previous data demonstrating a binding site for DXS (500 kDa) on the first domain of CD4 adjacent to the gp120 binding site and recognized by OKT4C and E monoclonal antibodies. Hence disruption of the CD4-gp120 interaction is probably responsible for most of the observed antiviral activity of SPs toward HIV infection of lymphocytes. However, HIV infection and gp120 binding to monocytes was unaffected by SPs, probably because SPs were unable to block the CD4-gp 120 interaction in monocytes.

Amino Acid Sequence↗
PubMed1994

Molecular mechanisms of IL-4 effect on HIV expression in promonocytic cell lines and primary human monocytes.

HIV-1 can productively infect mononuclear phagocytes derived from blood, bone marrow, brain, and lung. Interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha) have previously been shown to stimulate HIV replication in monocytes and macrophages. The mechanism of IL-4 stimulation was investigated and compared with the known effects of TNF-alpha. IL-4 up-regulated the expression of HIV mRNA within the first 2 days after infection of promonocytic U-937 cells and 3 to 4 days after infection of plastic-adherent blood macrophages with HIV-1. TNF-alpha also up-regulated production of HIV RNA but to a greater degree than IL-4, reaching a peak 3-4 days after addition. Northern blot analyses showed an increase in genomic and spliced RNAs at these times. However, there was reduced stimulation of HIV mRNA production when IL-4 and TNF-alpha were combined. These techniques are being used to further elucidate the mechanism of action of cytokines that inhibit HIV replication in purified human monocytes and macrophages.

Blotting, Northern↗
PubMed1994

Comparison of Giemsa and fluorescent monoclonal antibody staining of inoculated cell cultures for diagnosis of Chlamydia trachomatis.

Three methods of isolation and identification of Chlamydia trachomatis inclusions in cell monolayers were compared: Giemsa staining followed by darkfield microscopy of cycloheximide treated Buffalo green monkey kidney monolayers (BGM), fluorescent monoclonal antibody staining of cycloheximide treated BGM and of HeLa 229 monolayers. In an unselected group of 895 patients with suspected chlamydial infections including contacts of symptomatic patients, significantly more positive chlamydia isolates were detected with immunofluorescent monoclonal antibody staining of BGM and HeLa 229 than with Giemsa staining followed by darkfield microscopy on BGM. However, there was no disparity between the 2 staining methods with specimens from 156 patients with untreated non-gonococcal urethritis. In all chlamydia positive specimens, significantly more inclusions were seen after BGM-immunofluorescence than after HeLa-immunofluorescence or BGM-Giemsa. The extra cost associated with immunofluorescence staining was justified by the time saved in scanning.

Animals↗
PubMed1994

Early detection of human immunodeficiency virus type 1 infection in Australian infants at risk of perinatal infection and factors affecting transmission.

The earliest, most reliable methods for detecting human immunodeficiency virus type 1 (HIV-1) infection in infants at risk of perinatal HIV-1 and risks for transmission were investigated. Fifteen infants were followed prospectively from birth to age 21 to 48 months. Epidemiologic data on mothers during pregnancy were documented, and maternal proviral load (by quantitative polymerase chain reaction) and viral phenotype by HIV isolation were performed. Infants were assessed clinically and HIV isolation, HIV p24 antigen, polymerase chain reaction and total serum immunoglobulin determinations were performed. Four infants were infected. HIV isolation, HIV p24 antigen and polymerase chain reaction were positive within 3 months in all infected infants (100% sensitivity). False positive rates for a single test were 18, 9 and 9%, respectively. Median age of clearance of maternal antibodies was 13.4 +/- 2.1 months. Serum immunoglobulin G was significantly elevated after 6 months in all 4 infected infants. Advanced maternal age (> or = 30 years; Fisher's exact test, P > 0.014) was associated with transmission. A trend in higher maternal viral burden was observed among transmitters. Non-syncytium-inducing phenotype was present initially in all transmitting mothers.

Analysis of Variance↗
PubMed1994

Interleukin 4 and human immunodeficiency virus stimulate LFA-1-ICAM-1-mediated aggregation of monocytes and subsequent giant cell formation.

The effects of recombinant interleukin 4 (IL-4) on cell cluster and multinucleated giant cell (MGC) formation from human immunodeficiency virus (HIV)-infected and uninfected monocytes were examined. Human blood monocytes were isolated by centrifugal elutriation and monoclonal antibody-complement-dependent lysis of residual T cells, and infected with low passage HIV strains. Monocytes were exposed to recombinant IL-4 (1 to 20 ng/ml), continuously after inoculation with HIV. Monocyte expression of ICAM-1 but not LFA-1 was significantly enhanced by IL-4 although substrate adherence was a more potent stimulus. Monocyte cluster and MGC formation was quantified after fixation and staining with Giemsa. Clusters of HIV-infected and uninfected monocytes were consistently and significantly increased at 4 to 7 days after IL-4 stimulation. The combination of HIV and IL-4 was more stimulatory than either treatment alone. In two out of five uninfected and three out of seven HIV-infected monocyte cultures, MGC formation was also markedly increased at 10 to 14 days after stimulation. Incubation with anti-LFA-1 (anti-CD11a, anti-CD18) and anti-ICAM-1 (anti-CD54) monoclonal antibodies reduced IL-4-stimulated aggregation in HIV-infected and uninfected monocytes and subsequently reduced MGC formation. Anti-ICAM-1 was not as effective as anti-CD11a or anti-CD18 in inhibiting aggregation of HIV-infected monocytes and in these cultures anti-ICAM-2 was also inhibitory. Extracellular HIV antigen concentrations were not consistently reduced by anti-CD11a or anti-ICAM-1. Hence IL-4 markedly enhanced monocyte aggregation in both HIV-infected and uninfected monocytes, probably through enhanced LFA-1-ICAM-1 interactions in all cultures and LFA-1-ICAM-2 interactions in infected monocytes, leading subsequently to MGC formation in some cultures.

Antibodies, Monoclonal↗
PubMed1993

Herpes simplex virus type 2 antibody in patients attending antenatal or STD clinics.

OBJECTIVE: To determine the prevalence of antibody to herpes simplex virus type 2 (HSV-2) in patients attending a general public antenatal clinic and three public sexually transmitted disease (STD) clinics in Sydney. BACKGROUND: Highly specific tests for herpes simplex type 2 antibody, using the glycoprotein G2, have been recently introduced, allowing determination of past asymptomatic infection. Overseas studies have confirmed the long held suspicion that asymptomatic infection is more common than clinical genital herpes. The seroprevalence of HSV-2 in antenatal and STD clinic patients varies markedly in different countries. These are the first data available for Australia by means of this highly specific test. DESIGN: Cross-sectional study of seroprevalence in these two patient groups. Sera used in the antenatal study were those submitted for routine antenatal screening for viral markers. PARTICIPANTS: Two hundred and twenty-nine consecutive patients attending the Westmead Hospital antenatal clinics, and 107 consecutive patients attending three public STD clinics. HYPOTHESES: That Australian populations show a relatively high prevalence of past asymptomatic infection with HSV-2; and that higher rates of infection will be found in patients attending STD clinics and with past or current histories of STDs. MAIN OUTCOME MEASURES: Comparison of HSV-2 seroprevalence between antenatal clinic patients and STD clinic patients; and associations of HSV-2 antibody with age, sex, occupation, country of birth, a history of current or past STDs and antibody to HSV-1. RESULTS: Antibody to HSV-2 was found in 14.5% of antenatal clinic patients and 40% of STD clinic patients. None of the antenatal patients and less than half of the seropositive STD clinic patients reported clinical genital herpes. Associations with age, socioeconomic status and previous HSV-1 infection were less marked than in studies from the United States. Female STD clinic patients had a significantly higher seroprevalence than males and three times the seroprevalence of age-matched antenatal clinic patients. The correlation between HSV-2 antibody and current gonorrhoea was more marked than that between HSV-2 and other STDs. CONCLUSION: Asymptomatic infection with HSV-2 is quite common in Australian antenatal patients and more common in patients with STDs, who have higher rates of sexual exposure.

Adult↗
PubMed1993

Herpes simplex virus infection in pregnancy.

Genital infections in pregnancy caused by herpes simplex virus types 1 and 2 are a difficult management problem. Both primary and recurrent genital herpes can range from severe, extensive ulceration to asymptomatic virus shedding. Although neonatal herpes is a well recognized complication of symptomatic maternal primary genital infection at the time of delivery, most cases are associated with asymptomatic virus shedding and absence of a history of genital herpes. Neonatal herpes may also be acquired in utero and in the postnatal period. The diagnosis of herpes simplex infection is made most reliably by virus isolation or antigen detection from samples obtained from clinically apparent lesions. Serology is useful for diagnosing primary herpes, and newer serological techniques allow the detection of HSV-2 specific antibodies. Strategies to prevent neonatal herpes are limited by the failure of currently available diagnostic tests to rapidly detect women in labour who are at risk of transmitting herpes, by the absence of proven antenatal screening tests for HSV, and by transmission of herpes to neonates from asymptomatic mothers. The most useful current strategy is careful examination of the vulva and cervix for herpes lesions in women coming to labour. Caesarean section is indicated in women with clinically apparent genital herpes at delivery. Effective and safe antiviral agents are available for treatment of maternal and neonatal herpes.

Female↗
PubMed1993

Human immunodeficiency virus type 1 infection of human placental macrophages in vitro.

Placental macrophages (Hofbauer cells) were isolated and cultured in vitro to investigate their susceptibility to human immunodeficiency virus type 1 (HIV-1) infection. Of adherent cells, 80% expressed CD14, and > 99% were nonspecific esterase-positive. CD4 antigen was expressed at very low levels. CD4 mRNA could be detected in the cells by reverse transcription followed by polymerase chain reaction. The macrophages were infected productively after inoculation with low-passage blood isolates of cell-free HIV-1. Peak virus titers were detected 3-7 days after infection by HIV-1 antigen ELISA and reverse transcriptase assay. Replication of HIV-1 in placental macrophages was less than in blood monocytes. HIV-1 RNA was detected in placental macrophages by in situ hybridization 16 days after infection. Multinucleated giant cells were identified in some cultures, indicative of an HIV-induced cytopathic effect. Thus, placental macrophages can be infected productively with clinical isolates of HIV-1, and such cells may act as a reservoir of virus for transmission to the fetus in utero.

Antigens, CD↗
PubMed1993

Detection of immunoglobulin M antibodies to glycoprotein G-2 by western blot (immunoblot) for diagnosis of initial herpes simplex virus type 2 genital infections.

Western blots (immunoblots) for the detection of immunoglobulin M (IgM) antibodies specific for herpes simplex virus type 1 (HSV-1) and HSV-2 in patients' sera were developed. The locations of the type-specific glycoprotein G (gpG-2) of HSV-2 (92- and 140-kDa forms) and glycoprotein C of HSV-1 (gpC-1), which carries mostly type-specific antigenic epitopes, were checked with specific monoclonal antibodies. Western blot assays for IgM antibody to gpC-1 or gpG-2 were performed after depletion of IgG by precipitation with anti-human IgG. In patients with primary HSV-2 genital infections, seroconversion of IgM and IgG antibodies to both the 92- and 140-kDa forms of gpG-2 was observed, although both antibodies appeared in convalescent-phase serum after the first week. IgM and IgG antibodies to low-molecular-size polypeptides (40 to 65 kDa) were the first antibodies observed in patients with primary infection, but these antibodies were cross-reactive with HSV-1 and HSV-2. However, in patients with recurrent HSV-2 infections, IgG antibodies to both forms of gpG-2 and the low-molecular-size polypeptides were found no matter how early after onset the patient was bled, and IgM to gpG-2 did not appear. In patients with nonprimary initial genital HSV-2 infections, IgG antibody to HSV-1 was demonstrated in the first serum specimen, and HSV-2-specific IgM was found in 39% of the serum specimens. Hence, the Western blot assay can be used to test for IgM antibody to gpG-2, allowing for the retrospective diagnosis of inital HSV-2 infections and its use as a supplementary test to the gpG-2 IgG enzyme-linked immunosorbent assays developed elsewhere. In contrast, IgM antibody to gpG-2 is not usually detected in patients with recurrent HSV-2 infections.

Adult↗
PubMed1993

The reliability of serological tests for the diagnosis of genital herpes: a critique.

The reliability and limitations of the currently used routine tests for herpes simplex virus type 2 (HSV-2) antibody in Australia are reviewed. Six case reports illustrate the clinical dangers of overinterpretation of the currently available kits and the need for a readily available specific HSV-2 antibody test. In Sydney, HSV-2 causes approximately 85% of primary genital herpes and > 95% of recurrent genital herpes. Due to the extensive serological cross-reactivity between HSV-1 and HSV-2, currently available "type specific" commercial assays cannot reliably distinguish between the 2. Isolation of herpes simplex virus (HSV) or detection of HSV antigen in vesicle fluid is the preferred diagnostic test but may be overlooked or patients may have no visible lesions. The only accurate techniques for detecting HSV-2 specific antibody are the Western blot assay and an enzymatic immunoassay using glycoprotein G (gG-2), a component of the HSV-2 envelope. These tests, which still are restricted to research laboratories can be used to accurately identify people with previous exposure to HSV-2 (IgG) or to diagnose primary infection where virus isolation has not been performed or is impossible. Current commercially available antibody tests may have extensive cross-reactivity.

Adolescent↗
PubMed1993

Viral markers in HIV infection and AIDS.

Viral and immune markers are used for monitoring either progression of human immunodeficiency virus (HIV) disease or response to antiviral therapy. Ideal properties of viral markers are that they are present in all HIV-infected persons at all stages of disease, that they are related to disease pathogenesis, that they can be easily quantitated, that this quantitation correlates rapidly and predictably with both disease stage and response to antivirals, and that they can be developed into rapid, reproducible automated tests. Currently available viral markers include HIV p24 antigenemia (after acid glycine dissociation), anti-p24 antibody titres, quantitative DNA and RNA polymerase chain reaction performed on cells and plasma, and HIV isolate phenotype. In Australia, these markers have been studied in acute HIV seroconversion, in neonatal infection, in body fluids other than blood, and in monitoring of response to antiviral drug therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Identification of infection of an Australian resident with the human immunodeficiency virus type 2 (HIV-2).

OBJECTIVE: To present the first confirmed case of human immunodeficiency virus infection type 2 (HIV-2) in an Australian resident. CLINICAL FEATURES: HIV-2 infection in a west African man resident in Sydney was diagnosed in 1992 at Westmead Hospital, Sydney, by serological testing. He was asymptomatic and the blood CD4 T-lymphocyte concentration was not significantly reduced. Infection was probably acquired before migration to Australia. The patient was initially tested for HIV-1 antibody as part of an application for permanent residency. He was in no obvious risk group or transmission category. His serum was repeatedly positive by Genetic Systems enzyme immunoassay (EIA) and borderline by Abbott EIA, was reactive to the HIV-2 peptide on a synthetic envelope peptide assay, and was strongly reactive to all HIV-2 specific viral protein bands on an HIV-2 western blot test. HIV-2 was isolated by co-cultivation of the patient's peripheral blood mononuclear cells and identified by hybridisation using HIV-2 specific oligonucleotide probes, with further confirmation by polymerase chain reaction. INTERVENTION AND OUTCOME: The patient was counselled regarding the clinical course and prognosis of HIV-2 infection, the possible indications for zidovudine therapy, modes of transmission of the virus and safer sex precautions. CONCLUSIONS: This is the first documented case of HIV-2 infection diagnosed in Australia and raises the possibility of other undetected cases. The cost effectiveness of general testing for HIV-2 needs to be assessed and formal epidemiological sentinel programs should be established to monitor specific Australian populations.

AIDS Serodiagnosis↗
PubMed1992

Chronic colitis associated with human immunodeficiency virus infection.

OBJECTIVE: A clinical and pathological description of chronic colitis associated with human immunodeficiency virus (HIV) infection. DESIGN: A retrospective case review. SETTING: Tertiary referral institution and specialist gastroenterology practice. PATIENTS: A series of six patients with human immunodeficiency virus infection and chronic colitis observed for up to four years. RESULTS: The six patients had chronic diarrhoea for longer than six months, rectal bleeding, abdominal pain and stool leukocytosis. The mucosal pattern on colonoscopy showed diffuse proctocolitis, consisting of contact bleeding, superficial ulcerations, exudates, and/or loss of vascular pattern. Colonic biopsies showed a persisting diffuse colitis characterised principally by a mixed inflammatory cell infiltrate (mononuclear cells and neutrophils) and essentially preserved crypt architecture after six to 39 months of histological follow-up. The histopathology over this time frame was not typical of ulcerative colitis or Crohn's disease, nor of the conventionally described forms of infective colitis. HIV nucleic acid was identified by insitu hybridisation in colonic biopsies from four patients. In two of three patients tested, the presence of HIV DNA was confirmed by Southern blot analysis. No other microbial agent could be demonstrated as the cause of diarrhoea. At presentation all patients had CD4+ lymphocyte counts greater than 265 x 10(6)/L and none had the acquired immunodeficiency syndrome. Four patients have gone into remission, the other two patients were not in remission at four and a half to five years after onset. CONCLUSION: We suggest that chronic colitis may represent a new entity related to infection of the colon with human immunodeficiency virus.

Acquired Immunodeficiency Syndrome↗
PubMed1992

HCMV-DNA is detected more frequently than infectious virus in blood leucocytes of immunocompromised patients: a direct comparison of culture-immunofluorescence and PCR for detection of HCMV in clinical specimens.

In two studies comparing detection of human cytomegalovirus (HCMV) in 118 patients (93 of whom were immunocompromised) by the polymerase chain reaction (PCR) and virus isolation using either early antigen detection by culture-immunofluorescence or conventional cytopathic effect, DNA-PCR was found to be the most sensitive, followed by culture-immunofluorescence, then by cytopathic effect. Urine was inhibitory to the action of Taq polymerase; this was overcome by concentration of HCMV with PEG 6000 prior to gene amplification. Without PEG treatment, HCMV-DNA in 6 of the 11 specimens positive by culture-immunofluorescence was not detectable by PCR. In healthy seropositive individuals, HCMV-DNA was not detected in leucocytes. However, in immunocompromised patients with AIDS or transplants, and therefore at high risk of HCMV infection or reactivation, blood leucocytes were usually positive for HCMV-DNA (19/20), some for as long as 20 weeks after initial detection and persisting for long after culture-immunofluorescence became negative. Neither HCMV-RNA nor infectious HCMV were detected in the follow-up blood leucocyte specimens from immunocompromised patients who had detectable HCMV-DNA in these cells. These data suggest that persistence of HCMV-DNA in blood leucocytes of immunocompromised patients after reactivation or primary infection may be due to persistence of non-viable virus, residual HCMV genomic DNA, or latent HCMV-DNA.

Base Sequence↗
PubMed1992

Indirect ELISA for the detection of HSV-2 specific IgG and IgM antibodies with glycoprotein G (gG-2).

The glycoprotein G (gG-2) purified from HSV-2 infected cells has been reported to be useful for determination of HSV-2 type-specific antibodies using conventional ELISA formats. This study further confirmed the specificity of gG-2 and demonstrated the feasibility of a specific IgM assay. The gG-2 ELISA was developed to detect HSV-2 specific IgG and IgM antibodies in human sera with high levels of sensitivity and specificity. Of 45 patients with culture-proven recurrent HSV-2 genital infection 44 were reactive for gG-2 IgG. Of 30 sera from patients with culture-proven recent initial HSV-2 genital infection 29 were positive for gG-2 IgM. Three patients with primary HSV-2 genital infection showed gG-2 IgM in the convalescent but not in the acute sera. The IgG- and IgM-gG-2 ELISA showed high specificity. None of 40 sera from children were reactive by either assay. Only one of 94 sera from patients with antibody to herpesviruses other than HSV reacted in the IgG assay but none reacted in the IgM assay. There was no cross-reaction with sera from patients with proven HSV-1 infection with the gG-2 antigen. The results suggest that the IgG assay can be used for demonstration of past HSV-2 infection and the IgM assay for the diagnosis of HSV-2 in neonatal herpes and primary genital herpes, when cultures or rapid diagnostic techniques are unavailable.

Adult↗
PubMed1992

Nonspecific proctitis: association with human immunodeficiency virus infection in homosexual men.

In a cross-sectional study of 140 homosexual men attending a sexually transmissible diseases clinic, the association between the presence of antibody to the human immunodeficiency virus (HIV) and the presence of proctitis, as determined by histologic examination, as well as part or present exposure to other pathogens and details of sexual practices was analyzed. Significant associations with HIV seropositivity were found with the number of lifetime partners, positive treponemal serology, and evidence of previous infection with herpes simplex virus. However the major and unique finding was the strong and independent association between proctitis diagnosed by histologic criteria and seropositivity for HIV. Whether this is cause or effect awaits further elucidation.

Adult↗