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Biomedical subjects

P Fultz

Publications and source records attributed to P Fultz.

10 recordsLinked to original sources
PubMed1999

A multicenter, randomized, double-blind study to evaluate the safety, tolerability, and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in patients with liver pathology: results of a Phase III clinical trial.

The purpose of this study was to evaluate the safety and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in hepatic MRI of patients with suspected liver pathology. A Phase III, multicenter, randomized, double-blind, parallel group study was performed in adults with suspected liver pathology. All patients underwent contrast-enhanced computed tomography within 3 weeks prior to magnetic resonance scanning. Ninety-nine patients received OptiMARK, and 94 patients received Magnevist at a dose of 0.1 mmol/kg. Precontrast T1- and T2-weighted spin-echo imaging and T1-weighted gradient-echo imaging were performed, followed by T1-weighted gradient-echo imaging at 15-20 seconds, 1 minute, and 5 minutes after intravenous contrast injection. Three primary efficacy endpoints (confidence in lesion diagnosis, level of conspicuity, and lesion border delineation) were evaluated on the precontrast image set and compared with the pre plus postcontrast image set. Vital signs, physical examination, electrocardiograms (ECGs), and laboratory parameters (chemistry, hematology, and urinalysis) were measured at various time points. Adverse events were recorded. The study design and statistical analyses were chosen to demonstrate presumed equivalence of OptiMARK and Magnevist. There were no statistically significant differences in efficacy between OptiMARK and Magnevist as assessed by either blinded readers or the on-site principal investigators. No serious or unexpected adverse events were noted. Of the 193 patients receiving contrast media, 82 experienced a total of 154 adverse events. Thirty-three (21.4%) of these 154 adverse events were felt by the on-site investigators to be probably related to either study agent: 15 events in 9 patients in the OptiMARK group, and 18 events in 13 patients in the Magnevist group. Headache was the most common adverse event, occurring in 10.1% of the OptiMARK patients and 12.8% of the Magnevist patients. No clinically relevant trends were observed in any laboratory parameter or ECG findings in either treatment group. The results demonstrate the safety, efficacy, and equivalence of OptiMARK and Magnevist at a dose of 0.1 mmol/kg in hepatic magnetic resonance imaging of patients with suspected liver pathology.

Contrast Media↗
PubMed1996

An in vitro assay for acute pathogenicity of immunodeficiency viruses.

As a model for AIDS, experimental infections of old-world monkeys with various simian immunodeficiency viruses (SIV) are frequently carried out to study mechanisms of pathogenicity. For example, SIVsmmPBj14 was isolated from a pig-tailed macaque (Macaca nemestrina) suffering from acute viral disease. The molecular virus clone SIVsmmPBj1.9, which displays close genetic homology to other related SIVs, was shown to induce an acute viral disease in vivo after infection of pig-tailed and rhesus macaques. The acute pathogenicity of SIVsmmPBj1.9 was correlated with its unique ability to replicate in non-stimulated peripheral blood mononuclear cells from pig-tailed macaques. We have exploited this in vitro assay to resolve putative pathogenic genetic determinants of another SIV, namelySIVagm3, isolated from African green monkeys (Cercopithecus aethiops). Hybrid viruses encompassing subgenomic regions of SVsmmPBj1.9 in place of comparable regions of molecular virus clone SIVagm3mc were constructed and tested for their ability to replicate in non-stimulated PBMC from pig-tailed macaques and African green monkeys. Only those hybrid viruses comprising the U3 region of the viral LTR of SIVsmmPBj1.9 replicated in non-stimulated peripheral blood mononuclear cells. This in vitro assay will be used to determine the potential of SIV and of hybrid viruses between different SIVs to induce acute viral disease in vivo. It will help to avoid excessive experimental infections of monkeys with respective hybrid viruses for determining genetic determinants of acute pathogenicity of immunodeficiency viruses.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Antiviral effects of different CD4-immunoglobulin constructs against HIV-1 and SIV: immunological characterization, pharmacokinetic data and in vivo experiments.

The CD4 cell surface antigen belongs to the immunoglobulin superfamily and is the primary receptor for the human immunodeficiency virus 1 (HIV-1). The high affinity interaction between HIV-1 and CD4 is mediated by the viral envelope glycoprotein gp120. Recombinant soluble CD4 (rsCD4) has been shown in vitro to be an effective inhibitor of HIV-1 and HIV-2 propagation in lymphoid cells. A variety of antibody-like molecules were constructed, consisting of different parts of the extracellular domain of CD4 fused to immunoglobulin constant regions. The fusion proteins were expressed in mammalian cell lines and purified via affinity chromatography. The specificity and anti-viral effects of the different CD4-immunoglobulin constructs against HIV were analysed by different immunological tests, i.e., immunofluorescence, neutralisation and in vitro assays. In pharmacokinetic studies, differences were found in serum half-life between the four- and two-domain CD4 constructs in cynomolgus monkeys and between glycosylated and deglycosylated CD4-Fc constructs in rabbits. In two in vivo experiments using the four-domain CD4-Fc in SIV-infected macaques, no beneficial effects were observed.

Animals↗
PubMed1993

High viral load in lymph nodes and latent human immunodeficiency virus (HIV) in peripheral blood cells of HIV-1-infected chimpanzees.

We have examined human immunodeficiency virus type 1 (HIV-1) infection in chimpanzees by analyzing HIV-1 DNA and RNA in lymph nodes and peripheral mononuclear cells (PBMCs). Like certain asymptomatic HIV-infected persons, these chimpanzees had no detectable viral replication in their PBMCs. However, viral replication and a high viral load were observed in the lymphatic tissue. Despite the absence of viral replication in PBMCs, 1/1,000 to 1/10,000 of the PBMCs contained HIV-1 proviral DNA, and HIV transcription could be rapidly induced in these cells in vitro. These results provide direct evidence of cellular latency of HIV in vivo and suggest that HIV infection in chimpanzees may be a useful model for clinical latency of HIV infection in humans.

Animals↗
PubMed1992

[Experimental vaccination against HIV-1 protects the chimpanzee against challenge with injections of infected lymphocytes].

Two chimpanzees were immunized against HIV-1 : C-339, using whole inactivated HIV-1 followed by purified recombinant gp160 and a KLH-V3 peptide conjugate; and, C-499, using purified recombinant gp160 and p18gag followed by a mixture of uncoupled V3 peptides. The antigens were emulsified prior to use with one volume Syntex adjuvant SAF-1 containing 1 mg/ml Threonyl-MDP. The animals were challenged twice one year apart by the intravenous route, the first time with cell-free virus, using 40 chimpanzee infectious units (100 TCID50) of the titrated HTLV-IIIB virus stock from the National Cancer Institute, Frederick, MD; and the second time with cell-associated virus, using 6 x 10(5) viable peripheral blood mononuclear cells (PBMC) from a naive chimpanzee which had been injected 3 months earlier with cell-free virus and had become virus-positive within a few weeks. From end-point titration of C-087 PBMC on indicator human PBMC, using a reverse transcriptase assay, this represented the equivalent of at least 15 infected cells. A 3rd chimpanzee, C-435, a näive animal, was also injected with 6 x 10(5) PBMC from C-087 to serve as a positive control. The PMBC of the animals were co-cultivated with fresh human PBMC and assayed for reverse transcriptase on a regular basis. In parallel, ELISA and Western blot analyses were carried out. Virus was detected in the PBMC from C-435 beginning at 4 weeks after challenge. This was followed by seroconversion of the animal to the Env and Gag antigens. By contrast, no virus could be detected in the PBMC from chimpanzees C-499 and C-339 during 7 and 12 months, respectively. Lymph node biopsies and bone marrow aspirates from these animals remained virus-negative upon co-cultivation with human PBMC. PBMC, bone marrow aspirates and lymph node biopsies also scored HIV-negative by polymerase chain reaction. Finally, no anamnestic antibody response of the animals could be detected by ELISA, and no modification of their western blot profiles that could have signed HIV-infection were observed during the follow-up period. C-499 accidentally developed an infectious endocarditis with congestive liver and kidney failure and had to be euthanized at 7 months post-challenge. Specimens from its brain, kidneys, liver, mesenteric nodes, pancreas, salivary glands, and spleen were processed for co-cultivation with human PBMC. No evidence for the presence of virus could be detected by reverse transcriptase assays in any of these co-cultures.(ABSTRACT TRUNCATED AT 400 WORDS)

AIDS Vaccines↗
PubMed1990

HIV-infected humans, but not chimpanzees, have circulating cytotoxic T lymphocytes that lyse uninfected CD4+ cells.

It has been suggested that autoimmune phenomena contribute to the depletion of CD4+ T cells and the development of AIDS in HIV-1 infected humans based, in part, on observations that some HIV-1-infected humans have autoantibodies reactive with Ag expressed on uninfected CD4+ cells. In this study, 11 of 14 asymptomatic HIV-1-infected homosexuals and hemophiliacs, but none of 17 uninfected homosexuals or heterosexuals, were found to have cytotoxic lymphocytes in blood that can lyse uninfected CD4+ T cells from humans and chimpanzees but not human B lymphoblastoid cells or mouse T cells. The cytotoxic PBL were concluded to be CTL rather than NK cells, with the phenotype being CD3+, TCR-1 alpha beta+, CD8+, CD4-, CD16- based on findings that PBL-mediated lysis of uninfected CD4+ cells was 1) blocked by a mAb to CD3, which inhibits CTL but not NK activity; 2) diminished by treatment of PBL with a mAb to CD8 and C, but not by treatment with mAb to CD4 or CD16 and C; and 3) blocked by mAb WT31 directed against the TCR-1 alpha beta. In contrast, PBL from HIV-1-infected chimpanzees, which to date have not developed AIDS, lacked detectable CTL lytic for uninfected CD4+ cells.

Animals↗
PubMed1989

Genetic diversity of simian immunodeficiency virus.

We have demonstrated that the genetic diversity of simian immunodeficiency virus from African green monkeys (SIVagm) is much greater than that observed previously for individual HIV-1, HIV-2, or SIVmac isolates. Extensive genetic variation among SIVagm isolates and the high prevalence of green monkey infection without disease suggest that the virus has been in the green monkey population for a long time. We have also demonstrated that SIV from a sooty mangabey monkey (isolate SMM-7) is closer to SIVmac and HIV-2 than to HIV-1 and SIVagm. The extensive genetic diversity of SIVagm and the relatedness of SIVsmm to HIV-2 warrant continued examination of SIVagm and SIVsmm isolates from dispersed geographic regions. SIV strains much more closely related to HIV-1, HIV-2, or SIVmac may be found which would be reasonable candidates for recent cross-species transmission.

Animals↗