Rapid identification of Ebola virus and related filoviruses in fluid specimens using indirect immunoelectron microscopy.

Recent filoviral outbreaks in animal primates have raised public awareness of the potential for filoviruses to become a public health concern; methods that efficiently identify these viruses are therefore of high priority. An indirect immunoelectron microscopy method, which uses homologous guinea pig polyclonal antiserum, successfully identified Ebola-related (Reston) virus particles in serum and tissue culture fluid specimens with infectivity titres of 300 plaque forming units (pfu) per ml or more. The sensitivity of this procedure is sufficient to show virus in most acute phase sera, and is equal to that of the antigen capture enzyme linked immunosorbent assay (ELISA). The immunoelectron microscopy fluid technique can differentiate among antigenically distinct filoviruses in less than three hours. It should be valuable in the rapid diagnosis of potential filoviral infections.     

Early Breastfeeding Cessation Among HIV-Infected and HIV-Uninfected Women in Western Cape Province,South Africa

As part of the Mother-Infant Health Study, we describe infant feeding practices among HIV-infected and HIV-uninfected mothers over a 12-month period when the Western Cape Province prevention of mother-to-child transmission (PMTCT) program was transitioning from a policy of exclusive formula feeding to one of exclusive breastfeeding. Two hundred pairs of mother and HIV-uninfected infant were included in the analysis, among whom 81 women were HIV uninfected and breastfeeding. Of the 119 HIV-infected mothers, 50 (42%) were breastfeeding and 69 (58%) were formula feeding. HIV-infected mothers predominantly breastfed for 8.14 (7.71–15.86) weeks; HIV-uninfected mothers predominantly breastfed for 8.29 (8.0–16.0) weeks; and HIV-infected mothers predominantly formula fed for 50.29 (36.43–51.43) weeks. A woman’s HIV status had no influence on the time to stopping predominant breastfeeding (P?=?0.20). Our findings suggest suboptimal duration of breastfeeding among both HIV-infected and HIV-uninfected mothers. Providing support for all mothers postdelivery, regardless of their HIV status, may improve breastfeeding practices.     

Addressing Early Retention in Antenatal Care Among HIV-Positive Women Through a Simple Intervention in Kinshasa,DRC: The <Emphasis Type="Italic">Elombe “Champion” Standard Operating Procedure</Emphasis>

This cluster-randomized study aimed to assess the Elombe (“Champion”) standard operating procedure (SOP), implemented by providers and Mentor Mothers, on HIV-positive pregnant women’s retention between first and second antenatal visits. Sixteen facilities in Kinshasa were randomly assigned to intervention (SOP) or comparison (no SOP). Effect of the SOP was estimated using relative risk. Women in comparison facilities were more likely to miss second visits (RR 2.5, 95% CI 1.05–5.98) than women in intervention facilities (30.0%, n = 27 vs. 12.0%, n = 9, p < 0.002). Findings demonstrate that a simple intervention can reduce critical early loss to care in PMTCT programs providing universal, lifelong treatment.     

Differentiation of substrate and non-substrate inhibitors of transport system xc(-): an obligate exchanger of L-glutamate and L-cystine

In addition to the well-characterized sodium-dependent excitatory amino acid transporters (EAATs) present in the mammalian CNS, a chloride-dependent, sodium-independent transporter has also been identified that is capable of mediating the uptake of L-glutamate. Named system x(c)(-), this transporter is an obligate exchanger that normally couples the export of intracellular L-glutamate with the import of extracellular L-cystine. Two cell lines that express high levels of system x(c)(-) are used to delineate the pharmacology of the transporter and demonstrate that it is distinct from both the EAATs and EAA ionotropic receptors. Potent competitive inhibitors of system x(c)(-) include: L-homocysteate, ibotenate, L-serine-O-sulphate, (RS)-4-bromohomoibotenate, quisqualate, and (S)-4-carboxyphenylglycine. A fluorescent-based assay that allows system x(c)(-)-mediated exchange of L-glutamate and L-cystine to be followed in real time is used to assess substrate activity. Interestingly, those compounds that proved to be the most potent competitive inhibitors (e.g. L-quisqualate and 4-S-CPG) also proved to be the least active as substrates, suggesting that distinct structural features may control binding and translocation. Lastly, the finding that a number of system x(c)(-) inhibitors are also commonly used as probes of excitotoxic pathology (e.g., L-quisqualate, ibotenate and L-homocysteate) raises some interesting questions regarding the mechanisms through which these analogues produce CNS damage.     

Inhibition of tumor growth by a newly-identified activator for epidermal fatty acid binding protein

Our previous studies have demonstrated that expression of epidermal fatty acid binding protein (E-FABP) in tumor associated macrophages (TAMs) promotes macrophage anti-tumor activity by enhancing IFNβ responses in tumor models. Thus, E-FABP represents a new protective factor in enhancing tumor immune surveillance against tumor development. Herein, we report the compound 5-(benzylamino)-2-(3-methylphenyl)-1,3-oxazole-4-carbonitrile (designated EI-05) as a novel E-FABP activator for inhibition of mammary tumor growth. EI-05 was selected from the ZINC compound library using molecular docking analysis based on the crystal structure of E-FABP. Although EI-05 is unable to bind E-FABP directly, it significantly increases E-FABP expression in macrophages during inflammation. Stimulation of macrophages with EI-05 remarkably enhances lipid droplet formation and IFNβ production, which further promotes the anti-tumor activity of macrophages. Importantly, administering EI-05 in vivo significantly inhibits mammary tumor growth in a syngeneic mouse model. Altogether, these results suggest that EI-05 may represent a promising drug candidate for anti-tumor treatment through enhancing E-FABP activity and IFNβ responses in macrophages.     

Prevalence and incidence of herpes simplex virus type 2 infection among male Zimbabwean factory workers.

Stored sera from a cohort of 2397 male factory workers in Harare, Zimbabwe, were screened for herpes simplex virus type 2 (HSV-2)-specific antibodies, to estimate the prevalence and incidence of genital herpes infection and to assess the relation between HSV-2 and human immunodeficiency virus (HIV) acquisition. The prevalence of HSV-2 at enrollment was 39.8%. Correlates of HSV-2 seropositivity were HIV seropositivity, marital status, history of sexually transmitted disease (STD), older age, and higher income. The incidence of HSV-2 seroconversion during follow-up was 6.2/100 person-years. Correlates of HSV-2 seroconversion were enrollment while HIV-positive or seroconversion during follow-up, reported genital ulcer, history of STD, and number of sex partners. No evidence was found that HSV-2 infection was more likely to precede HIV or vice versa. HSV-2 and HIV seropositivity are strong markers for high-risk sexual behavior. Improved interventions targeted to populations in which the incidence of either viral infection is high are needed.     

Correlates of HIV Test Results Seeking and Utilization of Partner Counseling Services in a Cohort of Male Factory Workers in Zimbabwe

Correlates of individual HIV test results-seeking and utilization of partner counseling services were identified among male factory workers who participated in a longitudinal HIV prevention intervention study in Harare, Zimbabwe. Men working at participating factories were offered HIV voluntary counseling and testing (VCT) for themselves and their partners. While risk assessment counseling was offered in the workplace, result disclosure and partner counseling occurred at an off-workplace location. Of the 3,383 men undergoing risk assessment and testing, 1,903 (56%) chose to receive their test results and 230 (7%) brought their partners for VCT. Factors associated with receiving test results were history of STD and lower salary. Factors associated with bringing a partner for VCT were history of STD, being married, being employed at a factory with a peer educator, lower salary, and no prostitute contact. Incorporating VCT into STD treatment services is likely to reach a large number of men and their partners at highest risk for both types of infections. Because men are often the main decision-makers in sexual and reproductive matters, VCT must be easily accessible to urban, working African men.     

Pathogenesis of Lassa virus infection in guinea pigs.

A rodent model for human Lassa fever was developed which uses inbred (strain 13) and outbred (Hartley) guinea pigs. Strain 13 guinea pigs were uniformly susceptible to lethal infection by 2 or more PFU of Lassa virus strain Josiah. In contrast, no more than 30% of the Hartley guinea pigs died regardless of the virus dose. In lethally infected strain 13 guinea pigs, peak titers of virus (10(7) to 10(8) PFU) occurred in the spleen and lymph nodes at 8 to 9 days, in the salivary glands at 11 days, and in the lung at 14 to 16 days. Virus reached low titers (10(4) PFU) in the plasma and brain and intermediate titers in the liver, adrenal glands, kidney, pancreas, and heart. In moribund animals, the most consistent and severe histological lesion as an interstitial pneumonia. In contrast, the brain was only minimally involved. The immune response of lethally infected strain 13 guinea pigs, as measured by the indirect fluorescent antibody test, was detectable within 10 days of infection and was similar in timing and intensity to the fluorescent antibody test response of both lethally infected and surviving outbred animals. In contrast to the fluorescent antibody response, neutralizing antibody developed late in convalescence and was thus detected only in surviving outbred guinea pigs. The availability of a rodent model for human Lassa fever in uniformly susceptible strain 13 guinea pigs should facilitate detailed pathophysiological studies and efficacy testing of antiviral drugs, candidate vaccines, and immunotherapy regimens to develop control methods for this life-threatening disease in humans.