Patterning and Separating Infected Bacteria Using Host–Parasite and Virus–Antibody Interactions

Bacteria were selectively deposited on substrates patterned with poly(ethylene glycol) (PEG) microstructures by using host-parasite and virus-antibody interactions. In this scheme viruses were used to attach onto a host bacterium, Escherichia coli (E. coli). The E. coli expressing the virus were selectively adhered to the regions pretreated with an antibody against the virus proteins while E. coli without the virus showed no selectivity. Single or aggregated cell arrays were fabricated depending on the initial pattern size with respect to the size of E. coli. The current approach could be a general route to spatially positioning or controlling adhesion of other biological species that are not accessible by conventional methods and as a tool for separating and isolating specific cell populations based on host-parasite interactions.     

Pathogenesis of Churg–Strauss syndrome: Recent insights

Churg–Strauss syndrome (CSS) is a rare systemic necrotizing vasculitis associated with granuloma formation and severe blood and tissue eosinophilia. CSS occurs almost exclusively in patients with asthma. Its pathogenesis remains largely unknown, as triggering factors for CSS development have not been identified so far. AAb, such as anti-neutrophil cytoplasmic autoantibodies, are found in less than half of patients and possibly constitute a subtype of CSS with different clinical behaviour. On a cellular level, CSS is characterized by a strong Th2-type immune response. Th2-associated cytokines such as IL-4, IL-13 and IL-5 may precipitate the severe eosinophilia in CSS, while migration of Eos to inflammatory sites is possibly mediated by eotaxin-3. This review summarizes recent advances in the knowledge on epidemiology, clinical features, and pathogenesis of CSS.     

Flow Interactions with Cells and Tissues: Cardiovascular Flows and Fluid–Structure Interactions

Interactions between flow and biological cells and tissues are intrinsic to the circulatory, respiratory, digestive and genitourinary systems. In the circulatory system, an understanding of the complex interaction between the arterial wall (a living multi-component organ with anisotropic, non-linear material properties) and blood (a shear-thinning fluid with 45% by volume consisting of red blood cells, platelets, and white blood cells) is vital to our understanding of the physiology of the human circulation and the etiology and development of arterial diseases, and to the design and development of prosthetic implants and tissue-engineered substitutes. Similarly, an understanding of the complex dynamics of flow past native human heart valves and the effect of that flow on the valvular tissue is necessary to elucidate the etiology of valvular diseases and in the design and development of valve replacements. In this paper we address the influence of biomechanical factors on the arterial circulation. The first part presents our current understanding of the impact of blood flow on the arterial wall at the cellular level and the relationship between flow-induced stresses and the etiology of atherosclerosis. The second part describes recent advances in the application of fluid–structure interaction analysis to arterial flows and the dynamics of heart valves.     

Ribosome–Lamella Complexes in Injured Podocytes: Description of a Case and Review of the Literature

Ribosome-lamella complexes (RLCs) are mainly observed in a variety of hematological disorders and occasionally in solid neoplasms and in nonneoplastic diseases. These intracytoplasmic organelles are held to arise from rough endoplasmic reticulum, but, in agreement with more recent literature data, their function is still unclear. Ultrastructural analysis of glomeruli from a patient with focal segmental glomerulosclerosis secondary to metabolic syndrome disclosed significant foot process loss and abundant cytoskeletal proteins in major podocyte processes; two of the latter also displayed RLCs. This is the second report of RLCs in human renal glomerulus. Their close association with cytoskeletal proteins and lysosomes suggests a relationship with abnormal protein biosynthesis.     

Host expression of methylmalonyl-CoA mutase and tuberculosis: A missing link?

Bovine tuberculosis (bTB) is a disease caused by Mycobacterium bovis and closely related species of the Mycobacterium tuberculosis complex. bTB is an important health problem affecting livestock, wild animals and accounting for up to 10% of human TB cases worldwide. Several hypotheses have been considered to explain the low incidence of active TB despite high infection rates and the variable response to BCG vaccination. These hypotheses have considered genetic factors of immunized individuals and BCG strains, sensitization to environmental mycobacteria and metabolic processes. However, a link has not been established between genetic factors and metabolic processes that may affect the outcome of M. bovis infection and response to BCG vaccination. Herein we used published data linking host cholesterol metabolism with mycobacterial infection, persistence and disease outcome, and results obtained from studies of M. bovis infection and BCG vaccination in the wild boar bTB model to propose a hypothesis: host genetically-defined higher host methylmalonyl-CoA mutase (MUT) expression levels result in lower serum cholesterol concentration and tissue deposits that increase the protective immune response to M. bovis, thus resulting in resistance to bTB and better response to BCG vaccination. If the hypothesis is proven true, these results have important implications for the prevention and treatment of bTB in humans and for the eradication of bTB in wildlife reservoir hosts.     

Revisiting Libman–Sacks Endocarditis: A Historical Review and Update

Libman–Sacks (LS) endocarditis was first described by Libman and Sacks in 1924, and is characterized by sterile, verrucous valvular lesions with a predisposition for the mitral and aortic valves. It is now regarded as both a cardiac manifestation of systemic lupus erythematosus and, in recent years, of the antiphospholipid syndrome (APS). Though typically mild and asymptomatic, LS endocarditis can lead to significant complications, including severe valvular insufficiency requiring surgery, infective endocarditis, and thromboembolic events, such as stroke and transient ischemic events. Improvements in imaging modalities, particularly in echocardiography, have allowed better estimation of the prevalence of the disease, but further investigation is still needed into its pathogenesis, treatment, and association with APS.     

An Integrated Computational and Experimental Model of Nitric Oxide–Red Blood Cell Interactions

In blood vessels, nitric oxide homeostasis is maintained by its formation by endothelial nitric oxide synthase and its consumption in smooth muscle cells and in vascular lumen by red blood cell (RBC) encapsulated hemoglobin (Hb). Free hemoglobin has a very high reaction rate (k _Hb–NO ~ 10⁷ M⁻¹ s⁻¹) with NO as compared to RBC–Hb. Mechanisms of reduced NO uptake by RBC–Hb has been extensively studied in recent years. A critical factor in the investigation of NO–RBC interactions is delivery of NO. Common NO delivery methods include use of NO donors and bolus saturated NO solutions, which delivers NO homogenously and only in the vicinity of bolus, respectively. In this study, we developed a flow system that uses gaseous delivery of NO through a polymeric semi-permeable membrane to obtain precise and uniform NO concentrations for NO–RBC interactions. We conducted experiments using the flow system to study the effect of NO concentrations, hematocrit and RBC suspension flow rates on NO–RBC interactions. We developed a computational model to simulate NO transport and to estimate the reaction rate constant for NO–RBC interaction in the flow system. Our results showed that NO consumption of RBCs (i) increased linearly with an increase in available NO, and (ii) decreased with increase in RBCs suspension flow rate. We estimated the reaction rate constant for NO–RBC interactions to be 0.2 × 10⁵ M⁻¹ s⁻¹ which is ~1250-fold lower than NO consumption by free hemoglobin and ~2.5–20 fold slower than reported NO–RBC reaction rate.     

Stability and Predictive Validity of the Parent–Child Sleep Interactions Scale: A Longitudinal Study Among Preschoolers

Little research has examined the processes underlying children’s persistent sleep problems and links with later psychopathology. The current study examined the stability of parent–child sleep interactions as assessed with the parent-reported Parent–Child Sleep Interactions Scale (PSIS) and examined whether sleep interactions in preschool-age children predict sleep problems and psychiatric symptoms later in childhood. Participants included 108 preschool-age children (50% female) and their parents. Parents completed the PSIS when children were 3–5 years (T1) and again when they were 6–9 years (T2). The PSIS includes three subscales—Sleep Reinforcement (reassurance of child sleep behaviors), Sleep Conflict (parent–child conflict at bedtime), Sleep Dependence (difficulty going to sleep without parent)—and a total score. Higher scores indicate more problematic bedtime interactions. Children’s sleep problems and psychiatric symptoms at T1 and T2 were assessed with a clinical interview. PSIS scores were moderately stable from T1 to T2, and the factor structure of the PSIS remained relatively consistent over time. Higher total PSIS scores at T1 predicted increases in children’s sleep problems at T2. Higher PSIS Sleep Conflict scores at T1 predicted increases in oppositional defiant disorder symptoms at T2. Children with more sleep problems and higher PSIS Sleep Reinforcement scores at T1 showed increases in attention deficit/hyperactivity disorder, depressive, and anxiety symptoms at T2. These findings provide evidence for the predictive validity of the PSIS and highlight the importance of early parent–child sleep interactions in the development of sleep and psychiatric symptoms in childhood. Parent–child sleep interactions may serve as a useful target for interventions.