Treatment of latent Mycobacterium tuberculosis infection with 12 once weekly directly-observed doses of isoniazid and rifapentine among persons experiencing homelessness.

OBJECTIVES: To investigate treatment outcomes and associated characteristics of persons experiencing homelessness who received 12-weekly doses of directly observed isoniazid and rifapentine (3HP/DOT) treatment for latent TB infection (LTBI). METHODS: Among homeless persons treated with 3HP/DOT during July 2011 -June 2015 in 11 U.S. TB programs, we conducted descriptive analyses of observational data, and identified associations between sociodemographic factors and treatment outcomes. Qualitative interviews were conducted to understand programmatic experiences. RESULTS: Of 393 persons experiencing homelessness (median age: 50 years; range: 13-74 years), 301 (76.6%) completed treatment, 55 (14.0%) were lost to follow-up, 18 (4.6%) stopped because of an adverse event (AE), and 19 (4.8%) stopped after relocations or refusing treatment. Eighty-one (20.6%) had at least one AE. Persons aged ≥65 were more likely to discontinue treatment than persons aged 31-44 years. Programs reported difficulty in following up with persons experiencing homelessness because of relocations, mistrust, and alcohol or drug use. CONCLUSIONS: This study demonstrates the feasibility of administering the 3HP/DOT LTBI regimen to persons experiencing homelessness, a high-risk population.

Towards a systems level understanding of the oxygen response of Escherichia coli.

Escherichia coli is a facultatively anaerobic bacterium. With glucose if no external electron acceptors are available, ATP is produced by substrate level phosphorylation. The intracellular redox balance is maintained by mixed-acid fermentation, that is, the production and excretion of several organic acids. When oxygen is available, E. coli switches to aerobic respiration to achieve redox balance and optimal energy conservation by proton translocation linked to electron transfer. The switch between fermentative and aerobic respiratory growth is driven by extensive changes in gene expression and protein synthesis, resulting in global changes in metabolic fluxes and metabolite concentrations. This oxygen response is determined by the interaction of global and local genetic regulatory mechanisms, as well as by enzymatic regulation. The response is affected by basic physical constraints such as diffusion, thermodynamics and the requirement for a balance of carbon, electrons and energy (predominantly the proton motive force and the ATP pool). A comprehensive systems level understanding of the oxygen response of E. coli requires the integrated interpretation of experimental data that are pertinent to the multiple levels of organization that mediate the response. In the pan-European venture, Systems Biology of Microorganisms (SysMO) and specifically within the project Systems Understanding of Microbial Oxygen Metabolism (SUMO), regulator activities, gene expression, metabolite levels and metabolic flux datasets were obtained using a standardized and reproducible chemostat-based experimental system. These different types and qualities of data were integrated using mathematical models. The approach described here has revealed a much more detailed picture of the aerobic-anaerobic response, especially for the environmentally critical microaerobic range that is located between unlimited oxygen availability and anaerobiosis.

Critical analysis of the Chiari malformation Type I found in children with lipomyelomeningocele.

OBJECT: Occasional comments are found in the literature regarding patients with lipomyelomeningocele and concomitant Chiari malformation Type I (CM-I). The object of this study was to explore the association between these two conditions. METHODS: The authors performed a retrospective database analysis of lipomyelomeningocele cases to identify cases of concomitant CM-I. Analysis of posterior fossa volume (based on the Cavalieri principle) was performed in all identified cases in which appropriate neuroimages were available, and the results were compared with those obtained in age-matched controls. Seven (13%) of 54 patients with lipomyelomeningocele were found to also have CM-I. Two of these were symptomatic (cervicothoracic syrinx and occipital headaches) and required posterior fossa decompression. No correlation was found between the amount of hindbrain herniation and the level of the conus medullaris or the type of lipomyelome-ningocele (for example, caudal or transitional). Volumetric studies of the posterior fossa revealed normal age-matched volumes in all but one patient (who had asymptomatic CM-I). CONCLUSIONS: The incidence of CM-I in patients with lipomyelomeningocele appears to be significantly greater than that of the general population and the association rate is too high for the finding to be a chance occurrence. Decreases in the volume of the posterior cranial fossa were not found in the majority of patients in this small cohort; therefore, the cause of the concomitant occurrence of lipomyelomeningocele and CM-I remains undetermined. Clinicians should consider obtaining imaging studies of the entire neuraxis in patients with lipomyelomeningoceles and should investigate other causes for syringes found in association with lipomyelomeningoceles.

Partial nectar loads as a cause of multiple nectar transfer in the honey bee (Apis mellifera): a simulation model.

Honey bee foragers transfer their nectar loads to receiver bees within the nest. Surprisingly, they often transfer to more than one receiver (published values range from 1.9 to 2.7). Several adaptive hypotheses have been proposed to explain why multiple transfer occurs. One hypothesis, information improvement, states that multiple transfer arises as an adaptive forager-driven process. Foragers use the delay in finding a receiver to assess the relative work capacities of foragers and receivers, performing recruitment dances when appropriate. Multiple transferring improves their delay information. We used a stochastic simulation model to investigate the non-adaptive partial loads hypothesis. We determined the extent to which partial crop loads and receiver filling and emptying rules (i.e. how much nectar to accept before leaving the transfer area) can cause multiple transfer. As many as 1.9 nectar transfers per returning forager were generated within biologically realistic parameter space. We suggest that much multiple transfer arises as a non-adaptive consequence of partitioning nectar foraging between foragers and receivers, but that this will also result in foragers having better information about the relative work capacities of foragers and receivers as a useful consequence. We suggest that the number of transfers caused by partial loads could also be increased by an adaptive forager-driven effort to improve their information concerning the balance of foragers and receivers and we outline a framework wherein the information improvement hypothesis can be directly tested.