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Biomedical subjects

R W Price

Publications and source records attributed to R W Price.

At least 55 records · Page 3Linked to original sources
PubMed1991

AIDS dementia complex and HIV-1 infection: a view from the clinic.

The AIDS dementia complex (ADC) is a clinical syndrome which characteristically presents as a "subcortical dementia" with cognitive, motor and behavioral changes. While the pathogenesis remains puzzling in a number of critical aspects, ADC likely relates in a fundamental way to HIV-1, itself, rather than to a secondary, opportunistic condition. This review focuses on some of the clinical information which bears on the pathogenesis of this syndrome and its relation to HIV-1 infection. This information derives from studies of the clinical character of ADC, its epidemiology and natural history, cerebrospinal fluid analysis, neuroimaging results, clinical correlates of pathological findings and its response to antiviral therapy.

AIDS Dementia Complex↗
PubMed1991

Molecular characterization of human immunodeficiency virus type 1 cloned directly from uncultured human brain tissue: identification of replication-competent and -defective viral genomes.

All presently available replication-competent proviral clones of human immunodeficiency virus type 1 (HIV-1) are derived from cell culture-amplified virus. Since tissue culture is highly selective for viral strains with an in vitro growth advantage, such clones may not be representative of the biologically relevant virus present in vivo. In this study, we report the molecular cloning and genotypic characterization of 10 HIV-1 genomes directly from uncultured brain tissue of a patient with AIDS dementia complex. Targeting unintegrated circular HIV-1 molecules for recombinant lambda phage cloning, we obtained four full-length genomes with one or two long terminal repeats (LTRs), three defective genomes with internal deletions, two rearranged genomes with inverted LTR sequences, and one integrated proviral half with flanking cellular sequences. Nucleotide sequence analysis of these clones demonstrated chromosomal integration, circle formation, genomic inversion, and LTR-mediated autointegration of HIV-1 genomes in vivo. Comparison of a 510-bp hypervariable envelope region among 8 lambda phage-derived and 12 polymerase chain reaction-derived clones from the same brain specimen identified a predominant viral form as well as genetically divergent variants. Variability among 19 of 20 clones ranged between 0.2 and 1.2%. One clone exhibited 8.2% nucleotide sequence differences consisting almost exclusively of G-to-A changes. Transfection of the four full-length HIV-1 genomes identified one clone (YU-2) as replication competent and exhibiting growth characteristics similar to those of tissue culture-derived macrophage tropic strains of HIV-1. These results demonstrate, for the first time, that replication-competent HIV-1 genomes, complex mixtures of defective viral forms, and chromosomally integrated provirus persist in vivo. In addition, the brain-derived viral clones are expected to prove valuable for future studies of macrophage and neurotropism as well as for the analysis of other viral properties that are subject to in vitro selection pressures.

AIDS Dementia Complex↗
PubMed1991

HTLV-I-associated myelopathy associated with blood transfusion in the United States: epidemiologic and molecular evidence linking donor and recipient.

Six months after receiving 58 units of blood components, a 65-year-old white man from New York City, with no other risk factors for human T-lymphotropic virus type I (HTLV-I) infection, developed HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Investigation of blood donors identified a 25-year-old white Hispanic woman from Florida whose platelets had been given to the patient and who was seropositive for the virus on a serum specimen obtained 2 years after the donation. She was born in Cuba and had had 2 sexual relationships with men who either had been born in or had resided in the Caribbean. Polymerase chain reaction (PCR) studies of peripheral blood mononuclear cells indicated that both donor and recipient were infected with HTLV-I. Molecular studies of a 595-nucleotide sequence in the 5' envelope region of HTLV-I indicated that the viruses from donor and recipient were identical in each of 32 positions in which published HTLV-I sequences demonstrate molecular heterogeneity; the donor and recipient viruses were also identical in 2 additional positions in which they differed from all published sequences. Transfusion-associated HAM/TSP has occurred in the United States, but additional cases should be prevented by screening blood donations for HTLV-I. Molecular studies of HTLV-I may prove useful in defining the genetic heterogeneity of HTLV-I isolates in the United States and in studying transmission of this virus.

Adult↗
PubMed1991

Pursuit eye movement dysfunction in HIV-1 seropositive individuals.

Studies of smooth pursuit eye movements were conducted in 30 ambulatory drug-free HIV-1 seropositive patients who did not yet manifest marked clinical signs of the AIDS Dementia Complex. Seropositive patients demonstrated disturbances in pursuit eye movements that were correlated with extent of immunosuppression, with impairments on neuropsychological tests of fine motor control/speed, and with independent clinical staging of the AIDS Dementia Complex. The results provide quantitative evidence that oculomotor disturbances are present in HIV-1 seropositive individuals before the manifestation of marked AIDS Dementia Complex. For this reason, and because more severe eye movement impairments have been observed in patients with AIDS, quantitative eye movement studies may provide a useful neurobehavioral procedure for characterizing and monitoring progression of CNS involvement associated with HIV-1 infection from early in its course.

Adult↗
PubMed1990

Cerebrospinal fluid neopterin in human immunodeficiency virus type 1 infection.

We evaluated cerebrospinal fluid (CSF) concentrations of neopterin, a putative marker of activated macrophages, in 97 subjects infected with human immunodeficiency virus type 1 who had a spectrum of neurological complications. The highest CSF neopterin concentrations occurred in those with neurological opportunistic infections, primary central nervous systems lymphoma, and acquired immunodeficiency syndrome (AIDS) dementia complex. In general, the CSF concentration of neopterin was independent of CSF cell count and blood-brain barrier disruption to albumin. In the patients with AIDS dementia complex, CSF neopterin concentrations correlated with severity of disease and decreased in conjunction with clinical improvement following treatment with zidovudine. These results suggest that CSF neopterin, although not disease-specific, may be useful as a surrogate marker for the presence of AIDS dementia complex and its response to antiviral therapy.

AIDS Dementia Complex↗
PubMed1990

Evaluation of the AIDS dementia complex in clinical trials.

The AIDS dementia complex (ADC) is one of the most common and important causes of morbidity associated with infection by human immunodeficiency virus type 1 (HIV-1). The evaluation of ADC in clinical trials is significant not only because of the clinical impact of this syndrome, but also because of the value of measuring its cardinal features as an index of drug efficacy and because of its emerging role as a major clinical end point. The objectives of therapy include both prevention of ADC in the presymptomatic patient and alleviation of established disease. At present, the pathogenesis of ADC is incompletely understood in several critical aspects, particularly the processes underlying the clinical manifestations of central nervous system (CNS) HIV-1 infection and, further, how such processes are related to systemic disease. Consequently, it is not yet clear to what extent, or in which patients, it is necessary to achieve "therapeutic" drug levels within the CNS. Nevertheless, the assessment of ADC prevention and treatment relies principally on the complementary approach of neurological examination for diagnosis and neuropsychological testing for quantitative serial measurement of treatment effects. Additionally, surrogate markers in cerebrospinal fluid (CSF) may hold promise for objective, rapid assessment of treatment response and dose adjustment. Other measurements, including more routine CSF analysis, neuroimaging, and neurophysiological assessments, are used principally for differential diagnosis rather than for monitoring ADC status. Accumulating experience with available antiviral agents suggests that ADC can be effectively prevented and treated, at least for some period of time, and that assessment of this condition is indeed a valuable approach for measuring antiviral therapy.

AIDS Dementia Complex↗
PubMed1989

Cerebrospinal fluid beta 2 microglobulin in patients infected with human immunodeficiency virus.

We prospectively evaluated CSF concentrations of beta 2 microglobulin (beta 2M) in 65 human immunodeficiency virus type 1 seropositive patients. The highest concentrations occurred in those with lymphoma, neurologic opportunistic infections, and acquired immune deficiency syndrome dementia complex (ADC). There was a high correlation between the CSF beta 2M concentration and ADC severity, suggesting that CSF beta 2M may be useful as a marker for the development, progression, and perhaps response to treatment of ADC. Elevated CSF beta 2M was not due to CSF pleocytosis and was usually independent of blood-brain barrier dysfunction.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Dissociation of AIDS-related vacuolar myelopathy and productive HIV-1 infection of the spinal cord.

Although merging clinically within the spectrum of the AIDS dementia complex, vacuolar myelopathy is a pathologically distinct entity detected in up to 30% of autopsied patients succumbing to the late complications of human immunodeficiency virus type 1 (HIV-1) infection. Using immunohistochemistry and in situ hybridization to detect an HIV-1 core protein and viral mRNA, respectively, in tissue sections, and culture isolation to assess infectious virus in tissue homogenates, we found that vacuolar myelopathy was independent of productive HIV-1 infection of the spinal cord and brain. These results indicate that AIDS-associated vacuolar myelopathy is either not related directly to spinal cord HIV-1 infection or involves nonproductive infection and pathobiological processes distinct from those responsible for the multinucleated-cell inflammatory infiltrates that serve as histopathologic markers of productive CNS HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Malpractice liability of the military physician.

This article discusses the immunity from personal malpractice liability given to military physicians under the Gonzales Act. Exceptions are discussed in relation to recent court decisions.

Humans↗
PubMed1988

Incorporation and metabolism of 2'-fluoro-5-substituted arabinosyl pyrimidines and their selective inhibition of viral DNA synthesis in herpes simplex virus type 1 (HSV-1)-infected and mock-infected Vero cells.

The incorporation and metabolism of 2'-fluoro-5-substituted arabinosyl pyrimidine analogs, and their selective inhibition of viral DNA synthesis in herpes simplex virus type 1 (HSV-1)-infected and mock-infected Vero cells were studied by HPLC and CsCl isopycnic density gradient analysis of isolated DNAs. The amounts of radiolabeled analogs incorporated as parent compound following 10 microM exposure for 4 h were 10-fold higher in HSV-1-infected vs mock-infected cells for 2'-fluoro-5-difluoromethyl-Ara-U (F2FMAU); 4.3-fold higher for 5-ethyl deoxyuridine (EdU); 2.6-fold higher for 2'-fluoro-5-methyl-Ara-U (FMAU) and 1.7-fold higher for dThd. For 2'-fluoro-5-ethyl-Ara-U (FEAU), 3.0 pmole of unchanged moiety was incorporated per 10(6) HSV-1-infected cells but no incorporation was detected in mock-infected cells. HPLC profiles showed that the percentages of radiolabeled analogs incorporated as parent compound in the DNA extracted from HSV-1-infected cells were 31.0% for F2FMAU, 99.6% for EdU, 83.5% for FEAU and 98.3% for FMAU; from mock-infected cells, they were 63.6% for F2FMAU, 96.7% for EdU, 97.3% for FMAU and no incorporation into DNA for FEAU was detected. CsCl density gradient analyses of isolated DNA showed that viral DNA synthesis was inhibited 98% by 10 microM FEAU, 92% by 10 microM F2FMAU, 90% by 2 microM FMAU and 80% by 50 microM EdU, whereas cellular DNA synthesis was inhibited by 53, 44, 61, 66 and 54%, respectively. We conclude that: (a) FEAU incorporation into host-cell DNA was not detectable but FEAU was selectively incorporated into HSV-infected cells; (b) FMAU and FEAU were metabolically stable; however, F2FMAU was extensively metabolized; (c) FEAU and F2FMAU were among the most selective inhibitors of HSV-1 DNA synthesis while allowing cellular DNA synthesis to continue.

Animals↗
PubMed1988

The brain in AIDS: central nervous system HIV-1 infection and AIDS dementia complex.

Infection with human immunodeficiency virus type 1 (HIV-1) is frequently complicated in its late stages by the AIDS dementia complex, a neurological syndrome characterized by abnormalities in cognition, motor performance, and behavior. This dementia is due partially or wholly to a direct effect of the virus on the brain rather than to opportunistic infection, but its pathogenesis is not well understood. Productive HIV-1 brain infection is detected only in a subset of patients and is confined largely or exclusively to macrophages, microglia, and derivative multinucleated cells that are formed by virus-induced cell fusion. Absence of cytolytic infection of neurons, oligodentrocytes, and astrocytes has focused attention on the possible role of indirect mechanisms of brain dysfunction related to either virus or cell-coded toxins. Delayed development of the AIDS dementia complex, despite both early exposure of the nervous system to HIV-1 and chronic leptomeningeal infection, indicates that although this virus is "neurotropic," it is relatively nonpathogenic for the brain in the absence of immunosuppression. Within the context of the permissive effect of immunosuppression, genetic changes in HIV-1 may underlie the neuropathological heterogeneity of the AIDS dementia complex and its relatively independent course in relation to the systemic manifestations of AIDS noted in some patients.

Acquired Immunodeficiency Syndrome↗
PubMed1988

The AIDS dementia complex: some current questions.

The acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) commonly complicates the course of human immunodeficiency virus (HIV) infection and AIDS. Although many of its clinical aspects have recently been brought into clearer focus, and pathogenetic evidence has accrued implicating direct HIV brain infection, there remain a number of fundamental aspects of ADC and HIV nervous system infection that require clarification. These include clearer definition of the clinical syndrome and its variants; development of instrumentation for diagnosis and monitoring the disorder; definition of the epidemiology and natural history of both central nervous system HIV infection and ADC, which may seemingly be discordant; and understanding of both the viral pathogenesis and the biology of resultant brain dysfunction. Elucidation of these fundamental issues will enhance rational development and evaluation of therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Microglia in the giant cell encephalitis of acquired immune deficiency syndrome: proliferation, infection and fusion.

The autopsied brains of three homosexual men with acquired immune deficiency syndrome (AIDS), progressive encephalopathy and widespread multinucleated giant cell encephalitis were investigated by lectin and immunohistochemical methods to ascertain the cellular distribution of a human immunodeficiency virus (HIV) core protein, p25. Abundant viral antigen was present in all brains, limited to perivascular macrophages, microglial and multinucleated cells, some bearing elongated cytoplasmic processes. The multinucleated cells were consistently labelled by the lectin Ricinus communis agglutinin-1, a marker for microglia, which demonstrated process-bearing variants of these cells. The prominent staining of microglia for viral antigen and the morphological suggestion that they fuse with other microglia and/or macrophages to form the multinucleated cells characteristic of HIV encephalitis indicate that microglia are probably direct targets of HIV infection and serve to propagate and amplify this retroviral encephalitis.

Acquired Immunodeficiency Syndrome↗