The Cost of Uncertainty in Curing Epidemics

Motivated by the study of controlling (curing) epidemics, we consider the spread of an SI process on a known graph, where we have a limited budget to use to transition infected nodes back to the susceptible state (i.e., to cure nodes). Recent work has demonstrated that under perfect and instantaneous information (which nodes are/are not infected), the budget required for curing a graph precisely depends on a combinatorial property called the CutWidth. We show that this assumption is in fact necessary: even a minor degradation of perfect information, e.g., a diagnostic test that is 99% accurate, drastically alters the landscape. Infections that could previously be cured in sublinear time now may require exponential time, or orderwise larger budget to cure. The crux of the issue comes down to a tension not present in the full information case: if a node is suspected (but not certain) to be infected, do we risk wasting our budget to try to cure an uninfected node, or increase our certainty by longer observation, at the risk that the infection spreads further? Our results present fundamental, algorithm-independent bounds that tradeoff budget required vs. uncertainty.Comment: 35 pages, 3 figure

Mode of Delivery Decisions Among HIV-infected Mothers at an Urban Maternity Hospital in Nairobi, Kenya

Purpose: The objectives of this study are to describe mode of delivery decision making among HIV positive women, understand patient knowledge and attitudes regarding elective cesarean section (ECS) for prevention of mother-to-child transmission of HIV (PMTCT), and in turn quantify the use of ECS for PMTCT at an urban Kenyan maternity hospital. Methods: This is a descriptive cross-sectional study involving the survey of postpartum HIV-infected women delivering at Pumwani Maternity Hospital (PMH) in Nairobi, Kenya. Each participant was interviewed using a standardized questionnaire. Results: 250 women participated in this study over the course of three months. The rate of delivery by ECS for PMTCT was 4.0% (10/250), though 13.6% (34/250) planned this mode of delivery. Planning ECS was positively correlated with higher education levels (OR: 1.46; 95% CI: 1.09-1.94, p=0.028) and markers of higher socio-economic status including having a private toilet (OR: 2.89; 95% CI: 1.43-3.84, p=0.002) and living in a home with greater than one room (OR: 2.89; 95% CI: 1.07-7.80, p=0.033). The strongest correlates of ECS planning included having a surgical history (OR=5.86, 95% CI: 2.92-11.77, p\u3c0.001), attending clinic at PMH (OR=7.85, 95% CI: 4.63-13.30, p\u3c0.001), and knowledge of ECS (OR=24.50, 95% CI: 8.10-93.35, p\u3c0.001). Patient education regarding ECS for PMTCT was limited, and 64% (160/250) of participants had never heard of this PMTCT intervention. Most often cited concerns regarding cesarean section included increased recovery time (66.3%), minor complications (55.4%), and risk of death (48.7%). Post-counseling, 48.0% (120/250) of participants would choose elective cesarean section if offered, while 67.6% (169/250) would opt for this mode of delivery if the cost of ECS was the same as vaginal delivery. Correlates of ECS acceptability included high socioeconomic status (e.g. secondary education OR=1.64, 95% CI: 1.25-2.15, p\u3c0.001; ability to pay for delivery OR=1.40, 95% CI: 1.12-1.76, p=0.003), surgical history (OR=2.79, 95% CI: 1.21-6.43, p=0.011), and attendance at PMH antenatal clinic (OR=3.03, 95% CI: 1.54-5.98 p=0.001). Conclusions: Patient knowledge and uptake of ECS for PMTCT is limited at PMH. Although women are aware of the dangers of ECS, post-counseling acceptability of ECS, especially if the burden of cost is removed, is high

NF-κB Potentiates Caspase Independent Hydrogen Peroxide Induced Cell Death

The pro-survival activity of NF-κB in response to a variety of stimuli has been extensively characterized. Although there have been a few reports addressing the pro-cell death role of NF-κB, the precise mechanism of NF-κB's pro-cell death function still remains elusive.In the present study, we investigated the role of NF-κB in cell death induced by chronic insult with hydrogen peroxide (H(2)O(2)). Here, we show that NF-κB promotes H(2)O(2) induced caspase independent but PARP dependent fibroblast cell death. The pro-death activity of NF-κB is due to the DNA binding activity of RelA, which is induced through IKK- mediated IκBα degradation. NF-κB dependent pro-survival genes, Bcl-2 and XIAP, were significantly repressed, while NF-κB dependent pro-death genes, TNFα and Fas Ligand, were induced in response to H(2)O(2).We discovered an unexpected function of NF-κB, in that it potentiates chronic H(2)O(2) exposure induced cell death, and suggest that NF-κB mediates cell death through the repression of pro-survival genes and induction of pro-death genes. Since unremitting exposure of tissues to H(2)O(2) and other reactive oxygen species can lead to several degenerative disorders and diseases, our results have important implications for the use of NF-κB inhibitors in therapeutic drug design