Clinical predictors of disease severity during the 2009-2010 A(HIN1) influenza virus pandemic in a paediatric population.

A novel influenza virus emerged in the United States in spring 2009, rapidly becoming a global pandemic. Children were disproportionally affected by the novel influenza A(H1N1) pandemic virus [A(H1N1)pdm]. This retrospective electronic medical record review study aimed to identify clinical predictors of disease severity of influenza A(HIN1)pdm infection in paediatric patients. Disease severity was defined on an increasing three-level scale from non-hospitalized, hospitalized, and admitted to the intensive care unit (ICU). From April 2009 to June 2010, 696 children presented to Texas Children's Hospital's emergency department, 38% were hospitalized, and 17% were admitted to the ICU. Presenting symptoms associated with severe influenza were dyspnoea [odds ratio (OR) 5·82], tachycardia (OR 2·61) and fatigue (OR 1·96). Pre-existing health conditions associated with disease severity included seizure disorder (OR 4·71), obesity (OR 3·28), lung disease (OR 2·84), premature birth (OR 2·53), haematological disease (OR 2·22), and developmental delay (OR 2·20). According to model fitness tests, presenting symptoms were more likely to predict severe influenza than underlying medical conditions. However, both are important risk factors. Recognition of clinical characteristics associated with severe disease can be used for triaging case management of children during future influenza outbreaks.

NOD1 mediates interleukin-18 processing in epithelial cells responding to Helicobacter pylori infection in mice.

The interleukin-1 family members, IL-1ß and IL-18, are processed into their biologically active forms by multi-protein complexes, known as inflammasomes. Although the inflammasome pathways that mediate IL-1ß processing in myeloid cells have been defined, those involved in IL-18 processing, particularly in non-myeloid cells, are still not well understood. Here we report that the host defence molecule NOD1 regulates IL-18 processing in mouse epithelial cells in response to the mucosal pathogen, Helicobacter pylori. Specifically, NOD1 in epithelial cells mediates IL-18 processing and maturation via interactions with caspase-1, instead of the canonical inflammasome pathway involving RIPK2, NF-κB, NLRP3 and ASC. NOD1 activation and IL-18 then help maintain epithelial homoeostasis to mediate protection against pre-neoplastic changes induced by gastric H. pylori infection in vivo. Our findings thus demonstrate a function for NOD1 in epithelial cell production of bioactive IL-18 and protection against H. pylori-induced pathology.

Search for organic compounds in the lunar dust from the sea of tranquiblity.

A sample of lunar dust was examined for organic compounds. Carbon detected in concentrations of 157 micrograms per gram had a delta(13)C per mil (PDB) value of + 20. Treatment with hydrochloric acid yielded hydrocarbons of low molecular weight, suggesting the presence of carbides. The gas chromatogram of the acylated and esterified derivatives of the hydrolyzate was similar to that obtained for the Pueblito de Allende meteorite. There were no detectable amounts of extractable high-molecular-weight alkanes, aromatic hydrocarbons, isoprenoid hydrocarbons, normal alkanes, fatty acids, amino acids, sugars, or nucleic acid bases. Traces of porphyrins were found, perhaps arising from rocket exhaust materials.

Nod2 influences microbial resilience and susceptibility to colitis following antibiotic exposure.

Inflammatory bowel disease (IBD) etiology involves genetic susceptibility, environmental triggers, and the gut microbiome. Antibiotic exposure is associated with IBD, both in early life and adulthood. Here, we investigated whether Nod2-deficiency influenced response of the gut microbiota to antibiotics and subsequent colitis susceptibility. Wild-type and Nod2-/- littermate mice were treated with amoxicillin as adults or neonates, and fecal samples were collected for 16S rRNA sequencing. Five weeks after antibiotic exposure, dextran sulfate sodium (DSS) colitis was induced. Antibiotic treatment altered the microbiota of adult WT and Nod2-/- mice, but recovery was delayed in Nod2-/- mice. Neonatal antibiotic treatment significantly changed the microbiota at weaning in WT and Nod2-/- littermates; however, Nod2-/- mice maintained reduced microbial diversity 14 days after cessation of antibiotics. Although treatment of adult mice did not influence susceptibility to colitis, neonatally treated Nod2-/- mice developed a more severe colitis. Moreover, the colitis phenotype was transferable through fecal transplantation into germ-free Nod2-/- recipients, and was associated with changes in intestinal T cells and the cytokine milieu following inflammation. These data demonstrate that neonatal antibiotic exposure has long-lasting influence on the microbiota and mucosal immunity, and may explain how NOD2 contributes to the risk of intestinal inflammation.

TIR, CARD and PYRIN: three domains for an antimicrobial triad.

Innate immunity to microorganisms in mammals has gained a substantial interest during the last decade. The discovery of the Toll-like receptor (TLR) family has allowed the identification of a class of membrane-spanning receptors dedicated to microbial sensing. TLRs transduce downstream signaling via their intracellular Toll-interleukin-1 receptor (TIR) domain. More recently, the role of intracellular microbial sensors has been uncovered. These molecules include the Nod-like receptors Nod1, Nod2, Ipaf and Nalps, together with the helicase domain-containing antiviral proteins RIG-I and Mda-5. The intracellular microbial sensors lack the TIR domain, but instead transduce downstream signals via two domains also implicated in homophilic protein-protein interactions, the caspase activation and recruitment domain (CARD) and PYRIN domains. In light with these recent findings, we propose that TIR, CARD and PYRIN domains represent the three arms of innate immune detection of microorganisms in mammals.

Innate immune responses of epithelial cells following infection with bacterial pathogens.

The ability to discriminate between pathogenic and non-pathogenic bacteria is extremely important for epithelial cells lining mucosal surfaces and is particularly so in colonic epithelial cells. Accumulating evidence suggests that bacterial recognition systems used by epithelial cells are very different from those in cells of the myeloid lineage and are likely to have developed to maintain mucosal surfaces in a state of homeostasis with the normal microbial flora. Bacterial invasion of epithelial cells or breach of the epithelial barrier provides a signal to epithelial cells to initiate inflammatory responses, which are key events for the clearance of the infecting microbe. Therefore, elucidation of the mechanisms by which epithelial cells recognize bacteria and bacterial products, and of the nature of the innate immune responses that are triggered by these factors are important for our understanding of both the immunology of mucosal surfaces and bacterial pathogenesis.

Enrichment of magnetic particles using temperature and magnetic field gradients induced by benchtop fabricated micro-electromagnets.

The active transport of analytes inside biosensing systems is important for reducing the response time and enhancing the limit-of-detection of these systems. Due to the ease of functionalization with bio-recognition agents and manipulation with magnetic fields, magnetic particles are widely used for active and directed transport of biological analytes. On-chip active electromagnets are ideally suited for manipulating magnetic particles in an automated and miniaturized fashion inside biosensing systems. Unfortunately, the magnetic force exerted by these devices decays rapidly as we move away from the device edges, and increasing the generated force to the levels necessary for particle manipulation requires a parallel increase in the applied current and the resultant Joule heating. In this paper, we designed a study to understand the combined role of thermal and magnetic forces on the movement of magnetic particles in order to extend the interaction distance of on-chip magnetic devices beyond the device edges. For this purpose, we used a rapid prototyping method to create an active/passive on-chip electromagnet with a micro/nano-structured active layer and a patterned ferromagnetic passive layer. We demonstrated that the measured terminal velocities of particles positioned near the electromagnet edge (∼5.5 µm) closely reflect the values obtained by multi-physics modelling. Interestingly, we observed a two orders of magnitude deviation between the experimental and modelling results for the terminal velocities of particles far from the electromagnet edge (∼55.5 µm). Heat modelling of the system using experimentally-measured thermal gradients indicates that this discrepancy is related to the enhanced fluid movement caused by thermal forces. This study enables the rational design of thermo-magnetic systems for thermally driving and magnetically capturing particles that are positioned at distances tens to hundreds of microns away from the edges of on-chip magnetic devices.

Intestinal Batf3-dependent dendritic cells are required for optimal antiviral T-cell responses in adult and neonatal mice.

Although we know a great deal about which types of dendritic cells (DCs) promote T-cell priming in the periphery, less is known about which DC subset(s) provoke antiviral responses within the gut. Here we report that conventional Zbtb46-dependent DCs were critically required for antiviral CD8+ T-cell responses against rotavirus (RV), the major cause of childhood gastroenteritis worldwide. Furthermore, we found that in adult mice, Batf3-dependent DCs were required for generating optimal RV-specific CD8+ T-cell responses. However, in contrast to mice that lack Zbtb46-dependent DCs, a significant amount of interferon gamma-producing RV-specific CD8+ T cells were still detected in the small intestine of RV-infected adult Batf3-/- mice, suggesting the existence of compensatory cross-presentation mechanisms in the absence of Batf3-dependent DCs. In contrast to adult mice, we found that Batf3-dependent DCs were absolutely required for generating RV-specific CD8+ T-cell responses in neonates. Loss of Batf3-dependent DCs also resulted in a skewed polyclonal CD4+ T-cell response in both adult and neonatal mice upon RV infection, although local and systemic RV-specific immunoglobulin A production kinetics and titers were unimpaired. Our results provide insights that inform early-life vaccination strategies against RV infection.

Interaction of Aspergillus fumigatus with the alveolar macrophage.

Aspergillus fumigatus is a human pathogen, able to cause invasive aspergillosis in immunosuppressed patients. In the immunocompetent situation inhaled conidia are easily cleared by the immune system. Knowledge of the cellular pathways involved in the innate immunity against A. fumigatus is poorly represented. Therefore, we aimed to investigate the immune response against A. fumigatus in murine alveolar macrophages in terms of MAP kinases, NF-kappaB and cytokine signalling. Our investigations revealed that in murine alveolar macrophages, MAP kinases, ERK and p38 are activated under in vitro conditions, following addition of A. fumigatus conidia. In vivo experiments, however, showed that only ERK is directly involved, because activation of p38 was negligible. Immunosuppression with corticosteroids inhibited phosphorylation of ERK and was directly accompanied with a strongly decreased level of TNF-alpha and additional cytokines. In addition, killing of A. fumigatus conidia is reduced using the ERK inhibitor. Therefore, ERK appears to be an essential MAP kinase in the defence against A. fumigatus. Activation of the transcription factor NFkappaB appeared only at late times after infection suggesting an association with the intracellular swelling of conidia.

The Bugs Within Our Body: The Human Microbiota.

The human microbiota is the ecological community of microorganisms that live within our bodies. Emerging evidence has revealed that dysregulation of the host-microbe symbiotic relationship contributes to the pathogenesis of a vast number of human diseases and impacts the efficacy and toxicity of therapeutic drugs. Therefore, a deeper understanding of the human microbiota is crucial to the development of therapeutic interventions that target the microbiota and also provides fundamental insights towards understanding intersubject variability in therapeutic outcomes.

Fine-structural changes in the midgut of old Drosophila melanogaster.

Variations of the mitochondrial structure with increasing age are of particular interest because the production of ATP is necessary for most cellular activities. Therefore, a senescent decrease of mitochondrial activity could jeopardize cell survival and function. We combined a statistical with a morphological approach to investigate these changes in mitochondrial size and structure of Drosophila melanogaster. The midgut epithelium is of special interest because previous research shows striking aging changes. Investigations of the mitochondria of flies of three age groups (10, 39, and 65 days) reveal an increase in size as well as in its standard deviation. This is linked to the fact that mitochondrial enlargement occurs especially in the luminal region. Ultrastructural studies show that with increasing age the mitochondria become more osmiophilic, their cristae disarranged, cristae-free areas can also be found, and there is an accumulation of homogeneous, granular and lamellar dense bodies. In addition, an accumulation of virus-like particles, fiber-shaped structures, reticular structures, and dense bodies without a surrounding membrane was found.

Accelerated aging of fasted Drosophila. Preservation of physiological function and cellular fine structure by thiazolidine carboxylic acid (TCA).

Thiazolidine carboxylic acid (TCA) is a natural liver metabolite whose Mg-salt increased lifespan of flies and mice (Miquel and Economos, 1979, Exp. Geront. 14: 279). We studied the physiological and cellular fine structural effects of various concentrations of TCA in the food of male Drosophila. Flies on 0.3% TCA at 27 degrees C had a reduced oxygen consumption rate (about 20% less than controls) at 3 wks of age while their mating capacity and speed of mating were preserved; the flies lived in various experiments 20-30% longer than controls. Apparently TCA improved the metabolic efficiency of the flies (possibly from less "waste" of energy due to improved mitochondrial coupling). However, flies on 0.9% TCA had a reduced mating capacity and lifespan (:toxicity) while at 0.1% TCA was ineffective. A similar dose-response relationship was found in young flies treated with TCA for 1 week and then deprived of food and water, a procedure found to induce accelerated physiological aging. TCA at the 0.3% and 0.6% level reduced the speed of development and the size of the enclosed flies. Electron microscopic investigation of wing muscle showed that 0.3% TCA had a protective effect on cellular fine structure. Though in starved controls (40% survivors after 24 hours of starvation) there was a total absence of glycogen granules, and a striking shrinkage and densification of mitochondria, TCA to a large extent protected muscle cells from these effects of starvation.

Review article: In vitro models in inflammatory bowel disease research--a critical review.

Research efforts in inflammatory bowel disease (IBD) have been directed towards the epithelium as it has become clear that epithelial cells play a critical role in inflammatory response. Most research involving IBD employs in vitro techniques. In vitro epithelial cell studies have played and are continuing to play a major role in providing specific information relevant to IBD. Thus, such studies have provided irrefutable evidence that epithelial responses can be induced by microbes/microbial products and by immune activation. Culture experiments have provided insights into the effects of individual cytokines and other inflammatory mediators on epithelial pathophysiology, injury and repair, apoptosis, necrosis, and other processes that may be involved in IBD. Activated epithelial cells can participate in and even orchestrate immune responses, by stimulating T cells (and possibly others) and by producing cytokines that recruit specific inflammatory cells. Physiological regulation of epithelial tight junctions has been demonstrated by in vitro studies; the implication of this information for treating IBD is just beginning to be explored. It is becoming increasingly clear that epithelial processing and presentation of antigens is critical to the outcome of the immune response.

Thin-layer chromatography of trinitrophenyl derivatives of amino acids in urine and plasma.

The preparation and separation by thin-layer chromatography of the trinitrophenyl derivatives of amino acids in plasma and urine is described. The semi-quantitative procedure presents a useful addition to existing methods for screening biological fluids for aminoacidopathies.

Modification of a Kowa RC-2 fundus camera for self-photography without the use of mydriatics.

Research on retinal circulation during space flight required the development of a simple technique to provide self monitoring of blood vessel changes in the fundus without the use of mydriatics. A Kowa RC-2 fundus camera was modified for self-photography by the use of a bite plate for positioning and cross hairs for focusing the subject's retina relative to the film plane. Dilation of the pupils without the use of mydriatics was accomplished by dark adaption of the subject. Pictures were obtained without pupil constriction by the use of a high speed strobe light. This method also has applications for clinical medicine.

Effects of simulated increased gravity on the rate of aging of rats: implications for the rate of living theory of aging.

Ever since Pearl proposed the rate of living theory of aging numerous studies have demonstrated its validity in poikilotherms. In mammals, however, satisfactory experimental demonstration is still lacking because an externally imposed increase of basal metabolic rate of these animals (e.g. by placement in the cold) is usually accompanied by general homeostatic disturbance and stress. The present study was based on the finding that rats exposed to slightly increased gravity are able to adapt with little chronic stress but at a higher level of basal metabolic expenditure (increased 'rate of living'). The rate of aging of 17-mth-old rats that had been exposed to 3.14 times normal gravity in an animal centrifuge for 8 mth was larger than of controls as shown by apparently elevated lipofuscin content in heart and kidney, reduced numbers and increased size of mitochondria of heart tissue, and inferior liver mitochondria respiration (reduced 'efficiency': 20% larger ADP: 0 ratio, P less than 0.01; reduced 'speed': 8% lower respiratory control ratio, P less than 0.05). On the other hand, steady-state food intake per day per kg body weight, which is presumably proportional to 'rate of living' or specific basal metabolic expenditure, was about 18% higher than in controls (P less than 0.01) after an initial 2-mth adaptation period. Finally, though half of the centrifuged animals lived only a little shorter than controls (average about 343 vs. 364 days on the centrifuge, difference statistically nonsignificant), the remaining half (longest survivors) lived on the centrifuge an average of 520 days (range 483-572) compared to an average of 574 days (range 502-615) for controls, computed from onset of centrifugation, or 11% shorter (P less than 0.01). Therefore, these results show that a moderate increase of the level of basal metabolism of young adult rats adapted to hypergravity compared to controls in normal gravity is accompanied by a roughly similar increase in the rate of organ aging and reduction of survival, in agreement with Pearl's rate of living theory of aging, previously experimentally demonstrated only in poikilotherms.

Long term effects of low doses of 56Fe ions on the brain and retina of the mouse: ultrastructural and behavioral studies.

Eight month old male C57BL6 mice were exposed without anesthesia to whole-body irradiation in circular holders. The mice were tested for behavioral decrements after 0.5 and 50 rads of Fe particle irradiation at 6 and 12 months post irradiation to obtain long term results. A standard maze was used and the animals were timed for completion thereof. A string test also was administered to the mice, testing their ability to grasp and move along a string to safety. The results from animals exposed to 50 rads were significantly different from [correction of fron] control results to p = < .001 in both systems of testing. The hippocampus (believed to be the location of environmental interaction in the brain) and the retina were examined for ultrastructural changes. The ultrastructural changes were similar to those we found in our Cosmos 782, 936 and in our Argon experiments. The mouse data indicate that iron particles were able to induce long term changes in the central nervous system which lead to behavioral impairment.

Comparative study of spermatogonial survival after x-ray exposure, high LET (HZE) irradiation or spaceflight.

Spermatogonial cell loss has been observed in rats flown on Space Lab 3, Cosmos 1887, Cosmos 2044 and in mice following irradiation with X-ray or with high energy (HZE) particle beams. Spermatogonial loss is determined by cell counting in maturation stage 6 seminiferous [correction of seminferous] tubules. With the exception of Iron, laboratory irradiation experiments (with mice) revealed a similar pattern of spermatogonial loss proportional to the radiation dose at levels less than 0.1 Gy. Helium and Argon irradiation resulted in a 5% loss of spermatogonia after only 0.01 Gy exposure. However, significant spermatogonial loss (45%) occured at this radiation level with Iron particle beams. The loss of spermatogonia during each space flight was less than 10% when compared to control (non-flight) animals. This loss, although small, was significant. Although radiation may be a contributing factor in the loss of spermatogonia during space flight, exposure levels, as determined by dosimetry, were not significant to account for the total cell loss observed.

Ultrastructural changes in tracheal epithelial cells exposed to oxygen.

White albino rats were sacrificed after 24, 36, 48, 72, and 96 h of exposure to 100% O2 at 1 atm. Tissue was prepared for the scanning electron microscope (SEM) by Critical Point Drying and for the transmission electron microscope (TEM) by plastic embedding. Scanning microscopy showed a loss of microvilli after 48 h of exposure. Cilia appeared relatively normal with SEM, but TEM revealed changes in the outer membrane. In TEM, nonciliated cells appeared swollen and often encroached on the ciliated cells. A heavy mucous blanket remained even after processing. All the changes observed that are induced by oxygen exposure contribute to mucostasis, reducing and/or halting mucociliary clearance.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: V. preflight studies on tolerancee to oxygen and heat. Part III. effects on eyes.

A study was made of the eyes of eight pocket mice exposed to oxygen at partial pressures of 8, 10, or 12 psi over a period of 7 d. At the termination of the exposure, the animals were decompressed to sea-level O2 either immediately or over a period of 30, 60, or 90 min. No pathological changes were found in any of the eyes, except in the retina of one of the animals exposed to 12 psi O2. Here, only a single rod photoreceptor was found damaged, an observation not regarded as significant. Hence, an oxygen partial pressure as high as 12 psi in the camister in which pocket mice were expected to fly on Apollo XVII would probably have no deleterious effect on the eyes of the animals.