PubMed · 9179110
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J Fawcett, L Tulman. 1997. Status versus ability in function.. https://doi.org/10.1016/s0895-4356(97)00011-5
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Chemokines are believed to play a role in the neuropathogenesis of AIDS through their recruitment of neurotoxin-secreting, virally infected leukocytes into the CNS. Levels of chemokines are elevated in brains of patients and macaques with HIV/SIV-induced encephalitis. The chemokine receptors CCR3, CCR5, and CXCR4 are found on subpopulations of neurons in the cortex of human and macaque brain. We have developed an in vitro system using both macaque and human fetal neurons and astrocytes to further investigate the roles of these receptors in neuronal response to inflammation. Here we report the presence of functional HIV/SIV coreceptors CCR3, CCR5, and CXCR4 on fetal human and macaque neurons and CCR5 and CXCR4 on astrocytes immediately ex vivo and after several weeks in culture. Confocal imaging of immunostained neurons demonstrated different patterns of distribution for these receptors, which may have functional implications. Chemokine receptors were shown to respond to their appropriate chemokine ligands with increases in intracellular calcium that, in the case of neurons, required predepolarization with KCl. These responses were blocked by neutralizing chemokine receptor in mAbs. Pretreatment of neural cells with pertussis toxin abolished responses to stromal-derived factor-1alpha, macrophage inflammatory protein-1beta, and RANTES, indicating coupling of CCR5 and CXCR4 to a Gialpha protein, as in leukocytes. Cultured macaque neurons demonstrated calcium flux response to treatment with recombinant SIVmac239 envelope protein, suggesting a mechanism by which viral envelope could affect neuronal function in SIV infection. The presence of functional chemokine receptors on neurons and astrocytes suggests that chemokines could serve to link inflammatory and neuronal responses.
In randomized HIV/AIDS clinical trials, CD4 lymphocyte counts and plasma HIV-1 RNA measurements are often used as endpoints. The comparison between treatment groups is mainly based on a summary measure of outcome, so-called summary statistic. Such analyses are often complicated by missing data occurring as drop-outs. For the most currently used summary statistics in these trials, we examined the impact of missing data occurring as drop-outs on test size, in order to help choosing between these statistics. A simulation of missing-data patterns was performed, using HIV-1 plasma RNA measurements as the main endpoint, to compare the effect of three plausible informative patterns, depending on treatment group, and on baseline or current plasma viral load, on eight different summary statistics. Missing data resulted in test sizes over the nominal value for the area under the curve minus baseline, the least-squares slope, the slope estimated with use of a mixed effects linear model, assuming a linear trend over the entire study, the difference between baseline and nadir, and the difference between baseline and week 24. The difference between baseline and week 8 was an acceptable summary with respect to the test size, but did not reflect accurately the durability of the effect of treatment. Two criteria appeared as the best summary statistics: the slope estimated by a mixed effects model, with a change of slope after two weeks of treatment, and to a lesser degree, the area under the curve after carrying forward the last observation.
BACKGROUND AND METHODS: Cytomegalovirus (CMV) has been implicated as a cofactor in the progression of human immunodeficiency virus type 1 (HIV-1) disease. We assessed 440 infants (75 of whom were HIV-1-infected and 365 of whom were not) who had known CMV status and were born to HIV-1-infected women and who were followed prospectively. HIV-1 disease progression was defined as the presence of class C symptoms (according to the criteria of the Centers for Disease Control and Prevention [CDC]) or CD4 counts of less than 750 cells per cubic millimeter by 1 year of age and less than 500 cells per cubic millimeter by 18 months of age. RESULTS: At birth the frequency of CMV infection was similar in the HIV-1-infected and HIV-1-uninfected infants (4.3 percent and 4.5 percent, respectively), but the HIV-1-infected infants had a higher rate of CMV infection at six months of age (39.9 percent vs. 15.3 percent, P=0.001) and continued to have a higher rate of CMV infection through four years of age (P=0.04). By 18 months of age, the infants with both infections had higher rates of HIV-1 disease progression (70.0 percent vs. 30.4 percent, P=0.001), CDC class C symptoms or death (52.5 percent vs. 21.7 percent, P=0.008), and impaired brain growth or progressive motor deficits (35.6 percent vs. 8.7 percent, P=0.005) than infants infected only with HIV-1. In a Cox regression analysis, CMV infection was associated with an increased risk of HIV-1 disease progression (relative risk, 2.59; 95 percent confidence interval, 1.13 to 5.95). Among children infected with HIV-1 alone, but not among those infected with both viruses, children with rapid progression of HIV-1 disease had higher mean levels of HIV-1 RNA than those with slower or no progression of disease. CONCLUSIONS: HIV-1-infected infants who acquire CMV infection in the first 18 months of life have a significantly higher rate of disease progression and central nervous system disease than those infected with HIV-1 alone.