Bacteriological diagnosis of Neisseria ovis. Apropos of a strain isolated from keratoconjunctivitis of lambs

The authors report a case of bacteriologic diagnosis of Neisseria ovis isolated from a keratoconjunctivitis of lamb. Difficulties of diagnosis and taxonomic position of N. ovis are briefly discussed.     

Free radical generation of protease-resistant prion after substitution of manganese for copper in bovine brain homogenate

The exchange between copper and seven transition metals is studied in a bovine brain obex homogenate according to the redox status of the medium. In reductive conditions, almost all the studied metals can substitute for copper when it is in the reduced form Cu+. This substitution is reversible, since copper uptake as Cu++ is restored in an oxidizing medium but only Co++, Ni++ and Mn++, in this decreasing order, can substitute perfectly for copper in bovine brain homogenate. To study free radical effects on bovine brain proteins, at first a copper substitution was processed in order to inhibit superoxide dismutase-like protective properties against free radicals in copper metalloproteins. Manganese was selected since a brain copper decrease correlated with a manganese increase is well-known in transmissible spongiform encephalopathies. Results for bovine brain homogenate, initially negative in the Western blot Prionics test, indicate that the substitution of manganese for copper in a reducing medium and exposure to UVA-induced free radicals produce proteinase K resistant prion. These findings suggest that an impairment in brain metal homeostasis leading to oxidative abnormalities may be involved in transmissible spongiform encephalopathies.     

Quantile causal mediation analysis allowing longitudinal data

Mediation analysis has mostly been conducted with mean regression models. With this approach modeling means, formulae for direct and indirect effects are based on changes in means, which may not capture effects that occur in units at the tails of mediator and outcome distributions. Individuals with extreme values of medical endpoints are often more susceptible to disease and can be missed if one investigates mean changes only. We derive the controlled direct and indirect effects of an exposure along percentiles of the mediator and outcome using quantile regression models and a causal framework. The quantile regression models can accommodate an exposure‐mediator interaction and random intercepts to allow for longitudinal mediator and outcome. Because DNA methylation acts as a complex “switch” to control gene expression and fibrinogen is a cardiovascular factor, individuals with extreme levels of these markers may be more susceptible to air pollution. We therefore apply this methodology to environmental data to estimate the effect of air pollution, as measured by particle number, on fibrinogen levels through a change in interferon‐gamma (IFN‐γ) methylation. We estimate the controlled direct effect of air pollution on the qth percentile of fibrinogen and its indirect effect through a change in the pth percentile of IFN‐γ methylation. We found evidence of a direct effect of particle number on the upper tail of the fibrinogen distribution. We observed a suggestive indirect effect of particle number on the upper tail of the fibrinogen distribution through a change in the lower percentiles of the IFN‐γ methylation distribution.     

Epigenetic Influences on Associations between Air Pollutants and Lung Function in Elderly Men: The Normative Aging Study

Background: Few studies have been performed on pulmonary effects of air pollution in the elderly—a vulnerable population with low reserve capacity—and mechanisms and susceptibility factors for potential effects are unclear.Objectives: We evaluated the lag structure of air pollutant associations with lung function and potential effect modification by DNA methylation (< or ≥ median) at 26 individual CpG sites in nine candidate genes in a well-characterized cohort of elderly men.Methods: We measured forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV₁), and blood DNA methylation one to four times between 1999 and 2009 in 776 men from the Normative Aging Study. Air pollution was measured at fixed monitors 4 hr to 28 days before lung function tests. We used linear mixed-effects models to estimate the main effects of air pollutants and effect modification by DNA methylation.Results: An interquartile range (IQR) increase in subchronic exposure (3 to 28 days cumulated), but not in acute exposure (during the previous 4 hr, or the current or previous day), to black carbon, total and nontraffic particles with aerodynamic diameter ≤ 2.5 μm (PM_2.5), carbon monoxide, and nitrogen dioxide was associated with a 1–5% decrease in FVC and FEV₁ (p < 0.05). Slope estimates were greater for FVC than FEV₁, and increased with cumulative exposure. The estimates slopes for air pollutants (28 days cumulated) were higher in participants with low (< median) methylation in TLR2 at position 2 and position 5 and high (≥ median) methylation in GCR.Conclusions: Subchronic exposure to traffic-related pollutants was associated with significantly reduced lung function in the elderly; nontraffic pollutants (particles, ozone) had weaker associations. Epigenetic mechanisms related to inflammation and immunity may influence these associations.Citation: Lepeule J, Bind MAC, Baccarelli AA, Koutrakis P, Tarantini L, Litonjua A, Sparrow D, Vokonas P, Schwartz JD. 2014. Epigenetic influences on associations between air pollutants and lung function in elderly men: the Normative Aging Study. Environ Health Perspect 122:566–572; http://dx.doi.org/10.1289/ehp.1206458     

肺癌侵犯左心房的MRI表现及病理解剖基础

探讨肺癌侵犯左心房的ＭＲＩ特点及其病理解部基础，为肺癌ＩＬ的ＭＲＩ诊提供依据。材料与方法：回顾性分析病理证实的１３例癌ＩＬＡ的ＭＲＩ表现及相关的手术病理资料，盲法判断ＭＲＩ征象瓶 手术病理对照。     

Isolation of mycoplasma cloacale from a number of different avian hosts in great Britain and France

Following the original isolation of Mycoplasma cloacale from a turkey in Great Britain, only one further turkey isolate has been obtained whereas the mycoplasma has been recovered from 2 species of wild ducks in Britain, and from 2 breeds of domestic ducks and from domestic geese in France. A few isolations have also been made from wild and exotic birds but M. cloacale has not been found in chickens.