Measurements of suspended sediment volume concentrations, particle size and number density are routinely collected in marine and fresh‐water environments with LISST‐100X instruments to understand ...sediment transport, biological processes and fundamental opto‐acoustic problems. A LISST‐100X was simultaneously deployed with a novel holographic camera (holocam) in UK coastal waters to assess the performance of the laser diffraction technique when measuring natural suspensions. Volume distributions from the LISST‐100X, truncated to exclude non‐overlapping size bins with the holocam, exhibit an increase in small particles and median particle size is elevated in comparison to the holocam by 20–40%. We observe positive offsets between LISST‐100X and holocam number distributions of up to 2 orders of magnitude for particle sizes between 58–218μm, with discrepancies rising to 4 orders of magnitude for finer and coarser sizes. To explain these differences, a novel multiscale representation of particle size is used. The method quantifies individual dimensions that make up any two‐dimensional geometrical structure, it can be used as a metric for particle complexity, and offers a plausible explanation for an apparent increase in small particles (<58μm) reported by the LISST‐100X. The results suggest that for non‐spherical natural suspensions the LISST‐100X may be sensitive to optical scattering from sub‐scales within larger particles, reporting them as individual particles regardless of the way in which they may be packaged into particles of larger overall size. We urge caution in over interpretation of LISST size distributions obtained in natural suspensions without verification with independent particle imaging.
Key Points
Comparison of LISST‐100X and submersible holocam particle size distributions
Observation of discrepancy between LISST‐100X and holocam number concentrations
Using circle packing methodology to infer impact of optical scatterers on LISST
Aims:
To review the burden of allergic and infectious diseases and the evidence for a link to microbial exposure, the human microbiome and immune system, and to assess whether we could develop ...lifestyles which reconnect us with exposures which could reduce the risk of allergic disease while also protecting against infectious disease.
Methods:
Using methodology based on the Delphi technique, six experts in infectious and allergic disease were surveyed to allow for elicitation of group judgement and consensus view on issues pertinent to the aim.
Results:
Key themes emerged where evidence shows that interaction with microbes that inhabit the natural environment and human microbiome plays an essential role in immune regulation. Changes in lifestyle and environmental exposure, rapid urbanisation, altered diet and antibiotic use have had profound effects on the human microbiome, leading to failure of immunotolerance and increased risk of allergic disease. Although evidence supports the concept of immune regulation driven by microbe–host interactions, the term ‘hygiene hypothesis’ is a misleading misnomer. There is no good evidence that hygiene, as the public understands, is responsible for the clinically relevant changes to microbial exposures.
Conclusion:
Evidence suggests a combination of strategies, including natural childbirth, breast feeding, increased social exposure through sport, other outdoor activities, less time spent indoors, diet and appropriate antibiotic use, may help restore the microbiome and perhaps reduce risks of allergic disease. Preventive efforts must focus on early life. The term ‘hygiene hypothesis’ must be abandoned. Promotion of a risk assessment approach (targeted hygiene) provides a framework for maximising protection against pathogen exposure while allowing spread of essential microbes between family members. To build on these findings, we must change public, public health and professional perceptions about the microbiome and about hygiene. We need to restore public understanding of hygiene as a means to prevent infectious disease.
Chronic inflammatory diseases (autoimmunity, allergy and inflammatory bowel diseases) are increasing in prevalence in urban communities in high-income countries. One important factor is reduced ...exposure to immunoregulation-inducing macro- and microorganisms and microbiota that accompanied mammalian evolution (the hygiene hypothesis or 'Old Friends' mechanism). Reduced exposure to these organisms predisposes to poor regulation of inflammation. But inflammation is equally relevant to psychiatric disorders. Inflammatory mediators modulate brain development, cognition and mood, and accompany low socioeconomic status and some cases of depression in developed countries. The risk of all these conditions (chronic inflammatory and psychiatric) is increased in urban versus rural communities, and increased in immigrants, particularly if they move from a low- to a high-income country during infancy, and often the prevalence increases further in second generation immigrants, suggesting that critical exposures modulating disease risk occur during pregnancy and infancy. Diminished exposure to immunoregulation-inducing Old Friends in the perinatal period may enhance the consequences of psychosocial stressors, which induce increased levels of inflammatory mediators, modulate the microbiota and increase the risk for developing all known psychiatric conditions. In later life, the detrimental effects of psychosocial stressors may be exaggerated when the stress occurs against a background of reduced immunoregulation, so that more inflammation (and therefore more psychiatric symptoms) result from any given level of psychosocial stress. This interaction between immunoregulatory deficits and psychosocial stressors may lead to reduced stress resilience in modern urban communities. This concept suggests novel interpretations of recent epidemiology, and novel approaches to the increasing burden of psychiatric disease.
Using 10 095 galaxies (B < 20 mag) from the Millennium Galaxy Catalogue, we derive B-band luminosity distributions and selected bivariate brightness distributions for the galaxy population subdivided ...by eyeball morphology; Sérsic index (n); two-degree Field Galaxy Redshift Survey (2dFGRS) η parameter; rest-(u−r) colour (global and core); MGC continuum shape; half-light radius; (extrapolated) central surface brightness; and inferred stellar mass-to-light ratio. All subdivisions extract highly correlated subsets of the galaxy population which consistently point towards two overlapping distributions: an old, red, inert, predominantly luminous, high central-surface brightness subset; and a young, blue, star forming, intermediate surface brightness subset. A clear bimodality in the observed distribution is seen in both the rest-(u−r)colour and log (n) distributions. Whilst the former bimodality was well established from Sloan Digital Sky Survey data, we show here that the rest-(u−r) colour bimodality becomes more pronounced when using the core colour as opposed to global colour. The two populations are extremely well separated in the colour-log(n) plane. Using our sample of 3314 (B < 19 mag) eyeball classified galaxies, we show that the bulge-dominated, early-type galaxies populate one peak and the bulge-less, late-type galaxies occupy the second. The early- and mid-type spirals sprawl across and between the peaks. This constitutes extremely strong evidence that the fundamental way to divide the luminous galaxy population (M
Regulation of the immune system is an important function of the gut microbiota. Increasing evidence suggests that modern living conditions cause the gut microbiota to deviate from the form it took ...during human evolution. Contributing factors include loss of helminth infections, encountering less microbial biodiversity, and modulation of the microbiota composition by diet and antibiotic use. Thus the gut microbiota is a major mediator of the hygiene hypothesis (or as we prefer, "Old Friends" mechanism), which describes the role of organisms with which we co-evolved, and that needed to be tolerated, as crucial inducers of immunoregulation. At least partly as a consequence of reduced exposure to immunoregulatory Old Friends, many but not all of which resided in the gut, high-income countries are undergoing large increases in a wide range of chronic inflammatory disorders including allergies, autoimmunity and inflammatory bowel diseases. Depression, anxiety and reduced stress resilience are comorbid with these conditions, or can occur in individuals with persistently raised circulating levels of biomarkers of inflammation in the absence of clinically apparent peripheral inflammatory disease. Moreover poorly regulated inflammation during pregnancy might contribute to brain developmental abnormalities that underlie some cases of autism spectrum disorders and schizophrenia. In this chapter we explain how the gut microbiota drives immunoregulation, how faulty immunoregulation and inflammation predispose to psychiatric disease, and how psychological stress drives further inflammation via pathways that involve the gut and microbiota. We also outline how this two-way relationship between the brain and inflammation implicates the microbiota, Old Friends and immunoregulation in the control of stress resilience.
Lung Remodeling in Pulmonary Tuberculosis Dheda, Keertan; Booth, Helen; Huggett, Jim F. ...
The Journal of infectious diseases,
10/2005, Letnik:
192, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Tuberculosis is a global public health catastrophe responsible for >8 million cases of illness and 2 million deaths annually. Pulmonary cavitation with cough-generated aerosol is the principle means ...of spread, and lung remodeling (healed cavitation, fibrosis, and bronchiectasis) is a major cause of lung disability, surpassing all other diffuse parenchymal lung diseases combined. Efficient granuloma turnover is mycobactericidal, and extracellular matrix is disbanded without scarring. In many with progressive disease, however, there is dysregulated granuloma turnover, liquefactive necrosis, and pathological scarring. The pathological mechanisms and the related immunological pathways underpinning these phenomena are reviewed in the present article. Further studies are needed to identify and develop specific immunotherapeutic interventions that target immunopathology, since they have the potential to substantially reduce spread
Objective To investigate the effect of maternal body mass index (BMI) on postdates pregnancy, length of gestation and likelihood of spontaneous onset of labour at term.
Design Retrospective cohort ...study.
Setting Swedish Medical Birth Register.
Population A total of 186 087 primiparous women (of whom 143 519 had spontaneous onset of labour at term) who gave birth between 1998 and 2002.
Methods Mann–Whitney test, one‐way analysis of variance, linear regression and single variable logistic regression.
Main outcome measures Postdates pregnancy (≥294 days or 42+0 weeks), length of gestation and likelihood of spontaneous onset of labour at term.
Results About 6.8% of pregnancies delivered postdates. Higher maternal BMI (kg/m2) during the first trimester was associated with longer gestation (P < 0.001) as was a greater change in BMI between the first and third trimesters (BMI measured on admission prior to delivery) with mean (SD) gestation at delivery of 280.7 (8.6) and 283.2 (8.6) days for increases in BMI of <2 and ≥10 kg/m2, respectively. Higher BMI during the first trimester was associated with a lower chance of spontaneous onset of labour at term. Compared with BMI 20 to <25 kg/m2, the odds ratios (95% CI) for spontaneous onset of labour at term were 1.21 (1.15–1.27) for BMI of <20 kg/m2, 0.71 (0.69–0.74) for BMI of 25 to <30 kg/m2, 0.57 (0.54–0.60) for BMI of 30 to <35 kg/m2 and 0.43 (0.40–0.47) for BMI of ≥35 kg/m2. Higher BMI during the first trimester (BMI of ≥35 kg/m2 compared with BMI of 20 to <25 kg/m2) was also associated with an increased risk of complications including stillbirth (OR 3.90, 95% CI 2.44–6.22), gestational diabetes (OR 5.61, 95% CI 4.61–6.83) and caesarean section (OR 2.39; 95% CI 2.20–2.59).
Conclusions Higher maternal BMI in the first trimester and a greater change in BMI during pregnancy were associated with longer gestation and an increased risk of postdates pregnancy. Higher maternal BMI during the first trimester was also associated with decreased likelihood of spontaneous onset of labour at term and increased likelihood of complications.
We used genetic Multi-Locus VNTR Analysis (MLVA) data gathered from surveillance efforts to better understand the ongoing bovine tuberculosis (bTB) epidemic in Northern Irish cattle herds. We ...modelled the factors associated with Mycobacterium bovis MLVA genotype richness at three analytical scales; breakdown level, herd level, and patch level, and compared the results between dairy and non-dairy production types.
In 83% of breakdowns and in 63% of herds, a single MLVA genotype was isolated. Five or more MLVA genotypes were found in less than 3 % of herds. Herd size and the total number of reactors were important explanatory variables, suggesting that increasing MLVA genotype richness was positively related to increases in the number of host animals. Despite their smaller relative size, however, the highest MLVA genotype richness values were observed in non-dairy herds. Increasing inwards cattle movements were important positive predictors of MLVA genotype richness, but mainly in non-dairy settings.
The principal finding is that low MLVA genotype richness indicates that small-scale epidemics, e.g. wildlife, contiguous farms, and within-herd recrudescence, are important routes of M. bovis infection in cattle herds. We hypothesise that these mechanisms will maintain, but may not explicitly increase, MLVA genotype richness. The presence of elevated MLVA richness is relatively rare and likely indicates beef fattening enterprises, which purchase cattle from over long distances. Cattle movements were furthermore an important predictor of MLVA genotype richness in non-dairy herds, but not in dairy herds; this may represent reduced cattle purchasing levels in dairy enterprises, compared to beef. These observations allude to the relative contribution of different routes of bTB infection between production types; we posit that infection associated with local factors may be more evident in dairy herds than beef herds, however in beef herds, inwards movements offer additional opportunities for introducing M. bovis into the herd.
Summary
Fully mycoheterotrophic plants can be difficult to place in plant phylogeny due to elevated substitution rates associated with photosynthesis loss. This potentially limits the effectiveness ...of downstream analyses of mycoheterotrophy that depend on accurate phylogenetic inference. Although mitochondrial genomic data sets are rarely used in plant phylogenetics, theory predicts that they should be resilient to long‐branch artefacts, thanks to their generally slow evolution, coupled with limited rate elevation in heterotrophs.
We examined the utility of mitochondrial genomes for resolving contentious higher‐order placements of mycoheterotrophic lineages in two test cases: monocots (focusing on Dioscoreales) and Ericaceae.
We find Thismiaceae to be distantly related to Burmanniaceae in the monocot order Dioscoreales, conflicting with current classification schemes based on few gene data sets. We confirm that the unusual Afrothismia is related to Taccaceae–Thismiaceae, with a corresponding independent loss of photosynthesis. In Ericaceae we recovered the first well supported relationships among its five major lineages: mycoheterotrophic Ericaceae are not monophyletic, as pyroloids are inferred to be sister to core Ericaceae, and monotropoids to arbutoids.
Genes recovered from mitochondrial genomes collectively resolved previously ambiguous mycoheterotroph higher‐order relationships. We propose that mitochondrial genomic data should be considered in standardised gene panels for inferring overall plant phylogeny.
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