Deficiency of mast cells in coronary artery endarterectomy of male patients with type 2 diabetes

Background

Increased fasting plasma glucose (FPG), which includes impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes, is a risk factor for arterial stiffness. While IFG is widely accepted as a cardiovascular risk factor, recent studies have argued that subjects with high-normal glucose level were characterized by a high incidence of cardiovascular disease. The purpose of this study is to investigate the relationship between FPG and arterial stiffness in non-diabetic healthy subjects.

Methods

We recruited 697 subjects who visited the health promotion center of a university hospital from May 2007 to August 2008. Age, sex, body mass index (BMI), resting heart rate, smoking habits, alcohol intake, exercise, blood pressure, medical history, FPG, lipid profile, high sensitivity C-reactive protein (hs-CRP), and Brachial-ankle pulse wave velocity (ba-PWV) were measured. We performed correlation and multiple linear regression analyses to divide the research subjects into quartiles: Q1(n = 172), 65 mg/dL ≤FPG < 84 mg/dL; Q2(n = 188), 84 mg/dL ≤FPG < 91 mg/dl; Q3(n = 199), 91 mg/dL ≤FPG < 100 mg/dL; Q4(n = 138), 100 mg/dL ≤FPG < 126 mg/dL.

Results

FPG has an independent, positive association with ba-PWV in non-diabetic subjects after correcting for confounding variables, including age, sex, BMI, blood pressure, resting heart rate, hs-CRP, lipid profile, and behavioral habits. The mean ba-PWV of the high-normal glucose group (Q3, 1384 cm/s) was higher than that of the low-normal glucose group (1303 ± 196 cm/s vs.1328 ± 167 cm/s, P < 0.05). The mean ba-PWV value in the IFG group (1469 ± 220 cm/s) was higher than that in the normoglycemic group (P < 0.05, respectively).

Conclusions

An increase in FPG, even within the normal range, was associated with aggravated arterial stiffness. Further research is needed to determine the glycemic target value for the prevention of arterial stiffness in clinical and public health settings.     

Determination of raloxifene and its glucuronides in human urine by liquid chromatography-tandem mass spectrometry assay

A selective, sensitive, accurate and precise liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of raloxifene and its three glucuronides: raloxifene-6-β-glucuronide (M1), raloxifene-4'-β-glucuronide (M2), raloxifene-6,4'-diglucuronide (M3) in urine samples is presented in this paper. To our knowledge the developed analytical method is the first fully validated method capable of simultaneous determination of raloxifene and its glucuronides in real urine samples. Moreover, for the first time a method for determination of raloxifene diglucuronide in relevant biological samples was introduced. Metabolites were obtained by a bioconversion process of raloxifene to its glucuronides using the microorganism Streptomyces sp. and were used as standards for validation. Urine samples were introduced to a simple solid phase extraction prior to the analysis by LC-MS/MS. The method was linear in a wide range with high determination coefficient (r(2) > 0.997). The limits of quantification achieved were 1.01, 1.95, 2.83 and 4.69 nM for raloxifene, M1, M2 and M3, respectively. The recoveries were higher than 92.5%, the accuracy was within 100 ± 8.8% and the precision was better than 12% for all compounds. The developed method was successfully applied to the real urine samples and showed to be appropriate for use in further research of still not completely discovered raloxifene pharmacokinetics. Furthermore, the presented method could also serve for a potential application in anti-doping analysis.     

The distribution of Toxoplasma gondii cysts in the brain of a mouse with latent toxoplasmosis: implications for the behavioral manipulation hypothesis

Background

The highly prevalent parasite Toxoplasma gondii reportedly manipulates rodent behavior to enhance the likelihood of transmission to its definitive cat host. The proximate mechanisms underlying this adaptive manipulation remain largely unclear, though a growing body of evidence suggests that the parasite-entrained dysregulation of dopamine metabolism plays a central role. Paradoxically, the distribution of the parasite in the brain has received only scant attention.

Methodology/Principal Findings

The distributions of T. gondii cysts and histopathological lesions in the brains of CD1 mice with latent toxoplasmosis were analyzed using standard histological techniques. Mice were infected per orally with 10 tissue cysts of the avirulent HIF strain of T. gondii at six months of age and examined 18 weeks later. The cysts were distributed throughout the brain and selective tropism of the parasite toward a particular functional system was not observed. Importantly, the cysts were not preferentially associated with the dopaminergic system and absent from the hypothalamic defensive system. The striking interindividual differences in the total parasite load and cyst distribution indicate a probabilistic nature of brain infestation. Still, some brain regions were consistently more infected than others. These included the olfactory bulb, the entorhinal, somatosensory, motor and orbital, frontal association and visual cortices, and, importantly, the hippocampus and the amygdala. By contrast, a consistently low incidence of tissue cysts was recorded in the cerebellum, the pontine nuclei, the caudate putamen and virtually all compact masses of myelinated axons. Numerous perivascular and leptomeningeal infiltrations of inflammatory cells were observed, but they were not associated with intracellular cysts.

Conclusion/Significance

The observed pattern of T. gondii distribution stems from uneven brain colonization during acute infection and explains numerous behavioral abnormalities observed in the chronically infected rodents. Thus, the parasite can effectively change behavioral phenotype of infected hosts despite the absence of well targeted tropism.     

Distribution,Disease Level and Virulence Variation of Bremia lactucae on Lactuca sativa in the Czech Republic in the Period 1999–2011

We report the distribution and disease level of downy mildew on lettuce (Lactuca sativa) and virulence variation in populations of its causal agent (Bremia lactucae) in the Czech Republic during the period 1999–2011. Disease incidence was not high; among a total of 92 different localities surveyed, 43.4% of them were infected by lettuce downy mildew at least once during the whole period. However, among individual years, differences were found in disease incidence that ranged from 4.8% (2009) to 66.7% (2004). A total of 128 isolates of B. lactucae collected from infected leaf samples in 35 different localities during the surveying period were included in the virulence analysis. Virulence was examined on a set of 19 differential genotypes of Lactuca sativa and Lactuca serriola (EU‐A test set). Isolates exhibited quite a broad variation in virulence to individual Lactuca differential genotypes. Eighteen of 19 virulence factors (v‐factors) tested were present in the samples. The most frequently detected factors were v1–4, v5/8, v6, v7, v10–14, v16, v36 and v38; factor v17 was not found. The most pronounced temporal shift was recorded for factors v36 and v38 whose frequency increased during the studied period. V‐factors 15, 17, 18 and 37 were present in low frequencies in a pathogen population, and their corresponding gene (Dm15) or resistance factors (R17, R18 and R37) may have the best potential for resistance breeding in the Czech Republic. Broad diversity of v‐phenotypes (63 different ones) was identified during the study period. The numbers of v‐factors per v‐phenotype (resp. isolate) varied within a range of 5–15. Within the 128 analysed isolates, only 9 v‐phenotypes were recorded repeatedly (three or more times). Possible reasons of recorded virulence variation are discussed.     

Interactions Between Testate Amoebae and Saprotrophic Microfungi in a Scots Pine Litter Microcosm

In all terrestrial ecosystems, testate amoebae (TA) encounter fungi. There are strong indications that both groups engage in multiple interactions, including mycophagy and decomposition of TA shells, processes which might be fundamental in nutrient cycling in certain ecosystems. Here, we present the results of an experiment focusing on interactions between TA and saprotrophic microfungi colonizing Scots pine (Pinus sylvestris L.) litter needles. The needles were collected from a temperate pine forest and cultivated in damp chambers. Over a few weeks, melanized mycelium of Anavirga laxa Sutton started to grow out of some needles; simultaneously, the common forest-soil TA Phryganella acropodia (Hertwig and Lesser) Hopkinson reproduced and spread around the mycelium. We investigated whether a potential relationship between TA and saprotrophic microfungi exists by comparing the composition of TA communities on and around the needles and testing the spatial relationship between the A. laxa mycelium and P. acropodia shells in the experimental microcosm. Additionally, we asked whether P. acropodia utilized the A. laxa mycelium as a nutrient source and screened whether P. acropodia shells were colonized by the microfungi inhabiting the experimental microcosm. Our results indicate that saprotrophic microfungi may affect the composition of TA communities and their mycelium may affect distribution of TA individuals in pine litter. Our observations suggest that P. acropodia did not graze directly on A. laxa mycelium, but rather fed on its exudates or bacteria associated with the exudates. The fungus Pochonia bulbillosa (Gams & Malla) Zare & Gams was often found parasitising encysted shells or decomposing already dead individuals of P. acropodia. TA and pine litter microfungi engage in various direct and indirect interactions which are still poorly understood and deserve further investigation. Their elucidation will improve our knowledge on fundamental processes influencing coexistence of soil microflora and microfauna.     

Habitat selection and the scale of ghostly coexistence among Arctic rodents

Competition between coexisting species existing near their stable equilibrium can be obscured if they occupy separate habitats. Theories of habitat selection promise an ability to reveal the underlying ghost of competition by using isodars to infer the behavioural map of habitat selection. We tested the theory with two years of data on abundance and habitat preference by three Arctic rodent species living at low density along a gradient of wet to dry tundra on Herschel Island in Canada's western Arctic. Generalist brown lemmings exhibited a constant partial preference toward wet tundra whereas specialist collared lemmings and voles occupied the driest and wettest zones respectively. Although both lemming species compete for habitats elsewhere in the Canadian Arctic, isodar analyses suggest that the three species occupy wet and dry habitats independently of one another on Herschel Island. Competition at this large scale may be hidden at low densities, however, if the wet‐dry dichotomy is too coarse. Analyses at a finer subdivision of habitat revealed that these species coexist by using different microhabitats. Collared lemmings shifted their niche towards even drier habitat as the abundance of brown lemmings increased. We were thus able to reveal the ghost of competition lurking at large scales through a more refined analysis at smaller scales of density‐dependent habitat use.     

Tryptophan Biosynthesis in Stramenopiles: Eukaryotic Winners in the Diatom Complex Chloroplast

Tryptophan is an essential amino acid that, in eukaryotes, is synthesized either in the plastids of photoautotrophs or in the cytosol of fungi and oomycetes. Here we present an in silico analysis of the tryptophan biosynthetic pathway in stramenopiles, based on analysis of the genomes of the oomycetes Phytophthora sojae and P. ramorum and the diatoms Thalassiosira pseudonana and Phaeodactylum tricornutum. Although the complete pathway is putatively located in the complex chloroplast of diatoms, only one of the involved enzymes, indole-3-glycerol phosphate synthase (InGPS), displays a possible cyanobacterial origin. On the other hand, in P. tricornutum this gene is fused with the cyanobacteria-derived hypothetical protein COG4398. Anthranilate synthase is also fused in diatoms. This fusion gene is almost certainly of bacterial origin, although the particular source of the gene cannot be resolved. All other diatom enzymes originate from the nucleus of the primary host (red alga) or secondary host (ancestor of chromalveolates). The entire pathway is of eukaryotic origin and cytosolic localization in oomycetes; however, one of the enzymes, anthranilate phosphoribosyl transferase, was likely transferred to the oomycete nucleus from the red algal nucleus during secondary endosymbiosis. This suggests possible retention of the complex plastid in the ancestor of stramenopiles and later loss of this organelle in oomycetes. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Lifetime-based photoconversion of EGFP as a tool for FLIM

Background

EGFP is a fluorescent tag extensively used in biological and biomedical research. Over the years many researches have gathered collections of cell lines bearing specific EGFP-tagged proteins. Despite its popularity some photochemical properties of EGFP remain undocumented and unused. We report on so far unexplored lifetime photoconversion of EGFP usable in FLIM.