The Neuronal Transition Probability (NTP) Model for the Dynamic Progression of Non-REM Sleep EEG: The Role of the Suprachiasmatic Nucleus

Little attention has gone into linking to its neuronal substrates the dynamic structure of non-rapid-eye-movement (NREM) sleep, defined as the pattern of time-course power in all frequency bands across an entire episode. Using the spectral power time-courses in the sleep electroencephalogram (EEG), we showed in the typical first episode, several moves towards-and-away from deep sleep, each having an identical pattern linking the major frequency bands beta, sigma and delta. The neuronal transition probability model (NTP) – in fitting the data well – successfully explained the pattern as resulting from stochastic transitions of the firing-rates of the thalamically-projecting brainstem-activating neurons, alternating between two steady dynamic-states (towards-and-away from deep sleep) each initiated by a so-far unidentified flip-flop. The aims here are to identify this flip-flop and to demonstrate that the model fits well all NREM episodes, not just the first. Using published data on suprachiasmatic nucleus (SCN) activity we show that the SCN has the information required to provide a threshold-triggered flip-flop for timing the towards-and-away alternations, information provided by sleep-relevant feedback to the SCN. NTP then determines the pattern of spectral power within each dynamic-state. NTP was fitted to individual NREM episodes 1–4, using data from 30 healthy subjects aged 20–30 years, and the quality of fit for each NREM measured. We show that the model fits well all NREM episodes and the best-fit probability-set is found to be effectively the same in fitting all subject data. The significant model-data agreement, the constant probability parameter and the proposed role of the SCN add considerable strength to the model. With it we link for the first time findings at cellular level and detailed time-course data at EEG level, to give a coherent picture of NREM dynamics over the entire night and over hierarchic brain levels all the way from the SCN to the EEG

Macrophage Replication Screen Identifies a Novel Francisella Hydroperoxide Resistance Protein Involved in Virulence

Francisella tularensis is a Gram-negative facultative intracellular pathogen and the causative agent of tularemia. Recently, genome-wide screens have identified Francisella genes required for virulence in mice. However, the mechanisms by which most of the corresponding proteins contribute to pathogenesis are still largely unknown. To further elucidate the roles of these virulence determinants in Francisella pathogenesis, we tested whether each gene was required for replication of the model pathogen F. novicida within macrophages, an important virulence trait. Fifty-three of the 224 genes tested were involved in intracellular replication, including many of those within the Francisella pathogenicity island (FPI), validating our results. Interestingly, over one third of the genes identified are annotated as hypothetical, indicating that F. novicida likely utilizes novel virulence factors for intracellular replication. To further characterize these virulence determinants, we selected two hypothetical genes to study in more detail. As predicted by our screen, deletion mutants of FTN_0096 and FTN_1133 were attenuated for replication in macrophages. The mutants displayed differing levels of attenuation in vivo, with the FTN_1133 mutant being the most attenuated. FTN_1133 has sequence similarity to the organic hydroperoxide resistance protein Ohr, an enzyme involved in the bacterial response to oxidative stress. We show that FTN_1133 is required for F. novicida resistance to, and degradation of, organic hydroperoxides as well as resistance to the action of the NADPH oxidase both in macrophages and mice. Furthermore, we demonstrate that F. holarctica LVS, a strain derived from a highly virulent human pathogenic species of Francisella, also requires this protein for organic hydroperoxide resistance as well as replication in macrophages and mice. This study expands our knowledge of Francisella's largely uncharacterized intracellular lifecycle and demonstrates that FTN_1133 is an important novel mediator of oxidative stress resistance

Interdisciplinary and transdisciplinary research: Finding the common ground of multi-faceted concepts

Inter- and transdisciplinarity are increasingly relevant concepts and practices within academia. While various definitions exist, a clear distinction between inter- and transdisciplinarity remains difficult. Although there is a wide consensus about the need to define and apply these approaches, there is no agreement over definitions. Building on data collected during the first year of the COST Action TD1408 “Interdisciplinarity in research programming and funding cycles” (INTREPID), this paper describes both tensions and common ground about the characteristics and building blocks of interand trans-disciplinarity. Drawing on empirical data from participatory workshops involving INTREPID network members coming from 27 different countries, the paper shows that diverse definitions of inter and trans-disciplinarity coexist within scientific literature and in the mind of researchers and practitioners. The understanding about the involvement of actors outside of academia also differs widely across scientific communities irrespective of disciplinary training or the research subjects. The focus should be on the knowledge that is required to deal with a specific problem, rather than discussing “if” and “how” to integrate actors outside the academia, and collaboration should start with joint problem framing. This diversity is, however, not an absolute obstacle to practice, since the latter is made possible through building blocks such as knowledge domains, problem- and solution- oriented approaches, common goals, as well as target knowledge. In order to move towards more effective inter- and transdisciplinary research, we identify the need for trained interdisciplinarity facilitators and ‘accompanying research’ (derived from the Danish term ‘følgeforskning’). These two roles can be essential to inter- and transdisciplinarity practices including the promotion of reflexivity

Circuit-based interrogation of sleep control.

Sleep is a fundamental biological process observed widely in the animal kingdom, but the neural circuits generating sleep remain poorly understood. Understanding the brain mechanisms controlling sleep requires the identification of key neurons in the control circuits and mapping of their synaptic connections. Technical innovations over the past decade have greatly facilitated dissection of the sleep circuits. This has set the stage for understanding how a variety of environmental and physiological factors influence sleep. The ability to initiate and terminate sleep on command will also help us to elucidate its functions within and beyond the brain

The bile salt glycocholate induces global changes in gene and protein expression and activates virulence in enterotoxigenic Escherichia coli

Pathogenic bacteria use specific host factors to modulate virulence and stress responses during infection. We found previously that the host factor bile and the bile component glyco-conjugated cholate (NaGCH, sodium glycocholate) upregulate the colonization factor CS5 in enterotoxigenic Escherichia coli (ETEC). To further understand the global regulatory effects of bile and NaGCH, we performed Illumina RNA-Seq and found that crude bile and NaGCH altered the expression of 61 genes in CS5 + CS6 ETEC isolates. The most striking finding was high induction of the CS5 operon (csfA-F), its putative transcription factor csvR, and the putative ETEC virulence factor cexE. iTRAQ-coupled LC-MS/MS proteomic analyses verified induction of the plasmid-borne virulence proteins CS5 and CexE and also showed that NaGCH affected the expression of bacterial membrane proteins. Furthermore, NaGCH induced bacteria to aggregate, increased their adherence to epithelial cells, and reduced their motility. Our results indicate that CS5 + CS6 ETEC use NaGCH present in the small intestine as a signal to initiate colonization of the epithelium

Surgical anatomy of the minimally invasive lateral lumbar approach

The lateral lumbar interbody fusion approach (LLIF), which encompasses the extreme lateral interbody fusion or direct lateral interbody fusion techniques, has gained popularity as an alternative to traditional posterior approaches. With rapidly expanding applications, this minimally invasive surgery (MIS) approach is now utilized in basic degenerative pathologies as well as complex lumbar degenerative deformities and tumors. Given the intimate relationship of the psoas muscle, and hence the lumbar plexus, to this MIS approach, several authors have examined the surgical anatomy of this approach. Understanding this regional neural anatomy is imperative given the potential for serious injuries to both the motor and sensory nerves of the lumbar plexus. In this review, we critically and comprehensively discuss all published studies detailing the surgical anatomy of the lateral lumbar approach with respect to the MIS LLIF techniques. This is a timely review given the rapidly growing number of surgeons utilizing this technique

Increased survival and reversion of iron-induced cardiac disease in patients with thalassemia major receiving intensive combined chelation therapy as compared to desferoxamine alone.

Myocardial iron overload is the leading cause of death in patients with beta-thalassemia major. An intensification monotherapy with deferoxamine (DFO) as well as a combination therapy with DFO and deferiprone (DFP) reduces myocardial iron and improves cardiac function. However, the prognosis for thalassemia major patients with established cardiac disease switched from DFO monotherapy to combined DFP/DFO chelation is unknown. Twenty-eight thalassemia major patients with cardiac disease were enrolled in a prospective study lasting 42+/-6 months. Fifteen (9 high-ferritin and 6 low-ferritin) were placed on DFP/DFO (DFP, 75 mg/kg t.i.d.; DFO, 40-50mg/kg over 8-12h at night 5-7 days/week), while 13 (5 high- and 8 low-ferritin) received DFO alone. No cardiac events were observed among high-ferritin patients on combination therapy, whereas 4 cardiac events (p=0.0049), including three deaths, occurred in high-ferritin patients on DFO monotherapy. These findings demonstrate that in thalassemia major patients with well-established cardiac disease combined iron-chelation therapy with DFP/DFO is superior to DFO monotherapy

Formas graves de leptospirose: aspectos clínicos, demográficos e ambientais Severe forms of leptospirosis: clinical, demographic and environmental aspects

São descritas as características de 1.016 pacientes internados com leptospirose no Hospital Couto Maia, Salvador, BA, entre 1993 e 1997. Aumento na precipitação pluviométrica mostrou relação com aumento do número de internamentos no mês subsequente. Sexo masculino correspondeu a 81,1% (824/1.016); a média da idade foi 35,7±15,4 anos. Quase 94% (778/829) dos 829 com informação sobre raça eram negros ou mulatos. Para idade igual ou superior a 18 anos, quase 93% não cursaram o segundo grau. A média do período de incubação foi estimado em 6,3±3,9 dias. A duração dos sintomas foi em média 6,1±2,4 dias. Episódios hemorrágicos corresponderam a 14,3% (145/1.016). A letalidade entre 1.009 pacientes não transferidos foi de 14,2% (143/1.009). Insuficiência renal foi a causa atribuída de morte em 76,2% (109/143). Os dados indicam que leptospirose é estreitamente relacionada com baixos níveis socioeconômicos e que aumento da precipitação pluviométrica precede surtos epidêmicos.<br>Characteristics of 1,016 patients hospitalized with leptospirosis in the Hospital Couto Maia, Salvador, BA, Brazil, between 1993 and 1997 are described. Higher pluviometric precipitation was related to an increase in the number of hospitalizations during the following month. Males corresponded to 81.1% (824/1,016) of these; mean age was 35.7±15.4 years. Almost 94% (778/829) of the 829 patients with information about race were black or mulatto (mixed race). For ages 18 years or above, almost 93% had not completed high school level. The mean incubation period was estimated as 6.3±3.9 days. Average duration of symptoms was 6.1±2.4 days. Hemorrhagic events corresponded to 14.3% (145/1,016). The case-fatality rate among 1,009 patients that were not transferred was 14.2% (143/1,009). Renal failure was the attributable cause of death in 76.2% (109/143). The data indicate that leptospirosis is closely related to lower socioeconomic levels, and that higher pluviometric precipitation antecedes the outbreaks