The influence of the immunostimulation by bacterial cell components derived from altered large intestinal microbiota on probiotic anti-inflammatory benefits

Using murine macrophage-like J774.1 cells and fecal precipitates prepared from the feces of elderly volunteers whose acute inflammation had been inhibited by LKM512 yogurt consumption, we investigated the likelihood that immunostimulation by altered intestinal bacterial cell components contribute to the anti-inflammatory benefits of this yogurt. Tumor necrosis factor-alpha production due to stimulation by fecal precipitates obtained during LKM512 yogurt consumption tended to be higher than due to stimulation by precipitates obtained from preconsumption (P=0.0827), although acute phase response was suppressed by LKM512 yogurt consumption. We suggest that the anti-inflammatory benefits of LKM512 yogurt on elderly volunteers are independent of direct immunostimulation by the bacterial cell components derived from altered intestinal microbiota.     

Application of a single‐colony coculture technique to the isolation of hitherto unculturable gut bacteria

Molecular studies have led to postulation of a relationship between gut microbiota and certain diseases. However, because studies of hitherto uncultured species in vivo are essential for characterizing the biology and pathogenic properties of gut bacteria, techniques for culturing and isolating such bacteria must be developed. Here, a technique is described that partially overcomes the obstacles that prevent detection of interbacterial communication in vitro and are thus responsible for the failure to culture certain bacterial species. For this purpose, a ring with a membrane filter at the bottom was designed and a relatively simple nutrient medium was used instead of conventional media. Gut bacteria were cocultivated in soft agar separated by the membrane filter to simulate interbacterial communication in vitro. Use of this soft agar coculture technique led to the successful isolation of hitherto uncultured bacteria and the demonstration of multistage interbacterial communication among gut bacteria in vitro. Cultivation and isolation of single colonies of bacteria that require other bacteria for growth will enhance efforts to better understand the physiological and pathogenic roles of gut microbiota.     

Delayed appearance of high altitude retinal hemorrhages

Background

Retinal hemorrhages have been described as a component of high altitude retinopathy (HAR) in association with altitude illness. In this prospective high altitude study, we aimed to gain new insights into the pathophysiology of HAR and explored whether HAR could be a valid early indicator of altitude illness.

Methodology/Principal Findings

28 mountaineers were randomly assigned to two ascent profiles during a research expedition to Mt. Muztagh Ata (7546 m/24,751 ft). Digital fundus photographs were taken prior to expedition at 490 m (1,607 ft), during expedition at 4497 m (14,750 ft = base camp), 5533 m (18,148 ft), 6265 m (20,549 ft), 6865 m (22,517 ft) and 4.5 months thereafter at 490 m. Number, size and time of occurrence of hemorrhages were recorded. Oxygen saturation (SpO₂) and hematocrit were also assessed. 79% of all climbers exhibited retinal hemorrhages during the expedition. Number and area of retinal bleeding increased moderately to medium altitudes (6265 m). Most retinal hemorrhages were detected after return to base camp from a high altitude. No post-expeditional ophthalmic sequelae were detected. Significant negative (SpO₂ Beta: −0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.

Conclusions/Significance

When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes. The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding. Retinal hemorrhages should not be considered warning signs of impending severe altitude illness due to their delayed appearance.     

Development of a gas chromatography silicon-based microsystem in clinical diagnostics

The accurate determination of biological parameters by means of rapid, on-line measurements at low-concentrations is an important task within the fields of pharmaceutical screening and medical diagnostic. Nevertheless, in biological samples, the analytes of interest are present as minor components in complex mixtures and with interfering species. Biosensors are the best candidates for these applications providing a direct solution to this need of accuracy, but their intrinsic selectivity often excludes all the other components in the sample. A separation step introduced prior to the sensing component could allow both the increase of selectivity with respect the interfering species and the identification of a large spectrum of molecular components in the sample. This work reports the development of a silicon-based integrated separation microsystem for gas chromatography aimed to biomedical applications, with particular emphasis to monitor the homovanillic acid (HVA) and vanillylmandelic acid (VMA) ratios in mass population screening for neuroblastoma diagnosis and prognosis. The miniaturised system consists of two main modules: (i) a metal oxide semiconductor detector and (ii) a micromachined separation capillary column. As first step, the metal oxide semiconductor capability to detect HVA and VMA has been demonstrated. Then, a technology for a silicon separation capillary microcolumn including the on-chip gas sensor housing has been proposed and a first prototype has been developed. The proposed microsystem is an analytical device with biosensing capabilities for diagnostic and biomedical applications, which yield an electronic signal proportional to the concentration of a specific analyte or group of analytes.     

PrP(106-126) activates neuronal intracellular kinases and Egr1 synthesis through activation of NADPH-oxidase independently of PrPc

Prion diseases are characterised by severe neural lesions linked to the presence of an abnormal protease-resistant isoform of cellular prion protein (PrPc). The peptide PrP(106-126) is widely used as a model of neurotoxicity in prion diseases. Here, we examine in detail the intracellular signalling cascades induced by PrP(106-126) in cortical neurons and the participation of PrPc. We show that PrP(106-126) induces the activation of subsets of intracellular kinases (e.g., ERK1/2), early growth response 1 synthesis and induces caspase-3 activity, all of which are mediated by nicotinamide adenine dinucleotide phosphate hydrogen-oxidase activity and oxidative stress. However, cells lacking PrPc are similarly affected after peptide exposure, and this questions the involvement of PrPc in these effects.     

Muscle activity in the leg is tuned in response to impact force characteristics

Based on results from quasi-static experiments, it has been suggested that the lower extremity muscle activity is adjusted in reaction to impact forces with the goal of minimizing soft-tissue vibrations. It is not known whether a similar muscle tuning occurs during dynamic activities. Thus, the purpose of this study was to determine the effect of changes in the input signal on (a) vibrations of lower extremity soft-tissue packages and (b) EMG activity of related muscles during heel-toe running. Subjects performed heel-toe running in five different shoe conditions. Ground reaction forces were measured with a KISTLER force platform, soft-tissue vibrations were measured with tri-axial accelerometers and muscle activity was measured using surface EMG from the quadriceps, hamstrings, tibialis anterior and triceps surae groups from 10 subjects. By changing both the speed of running and the shoe midsole material the impact force characteristics were changed. There was no effect of changes in the input signal on the soft-tissue peak acceleration following impact. A significant correlation (R2=0.819) between the EMG pre-activation intensity and the impact loading rate changes was found for the quadriceps. In addition, the input frequency was shown to approach the vibration frequency of the quadriceps. This evidence supports the proposed paradigm that muscle activity is tuned to impact force characteristics to control the soft-tissue vibrations.     

Clostridium glycyrrhizinilyticum sp. nov., a glycyrrhizin-hydrolysing bacterium isolated from human faeces

Screening of faecal bacteria for glycyrrhetic acid (GA) production by hydrolysing of glycyrrhizin (GL) resulted in the isolation of two strains, designated ZM35T and ZM38. Strains ZM35T and ZM38 were Gram-positive, obligate anaerobic, non-spore-forming and rod-shaped bacteria. Analysis of the 16S rRNA gene sequences indicated that strains ZM35T and ZM38 belonged to cluster XIVa of the genus Clostridium. The 16S rRNA gene sequences of strains ZM35T and ZM38 were identical. Strain ZM35T exhibited approximately 94% to 95% identity with the validly described species, Clostridium oroticum(94.5%), Eubacterium contortum(93.8%), Ruminococcus gnavus(94.5%) and R. torques(95.1%). In an experiment of DNA-DNA hybridization, it was confirmed that strains ZM35T and ZM38 were the same species. The guanine-plus-cytosine (G+C) content of strain ZM35T is 45.7 mol%. Based on the phylogenetic and phenotypic findings, we propose that strains ZM35T and ZM38 be assigned to a novel species named Clostridium glycyrrhizinilyticum. The type strain is ZM35T (=JCM 13368T=DSM 17593T).     

Maintenance of segment and appendage primordia by the Tribolium gene knödel

For homeotic and segment-polarity genes in Drosophila, a switch in gene regulation has been described that distinguishes patterning and maintenance phases. Maintenance of segment and organ primordia involves secondary patterning and differentiation steps, as well as survival factors regulating proliferation and organ size. In a screen for embryonic lethal mutations in the flour beetle Tribolium castaneum, we have recovered two alleles of the kn?del gene, which result in short, bag-like embryos. These embryos have severely reduced appendages and differentiate a cuticle that lacks most overt signs of segmentation. In addition, they lack bristles and display defects in the nervous system. Early patterning in kn?del mutant embryos is normal up to the extended germ band stage, as indicated by the formation of regular even-skipped (Tc'eve) and wingless (Tc'wg) stripes. Afterwards, however, these patterns degenerate. Similarly, proximo-distal growth and patterning of limbs are nearly normal initially, but limb primordia shrink, and proximo-distal patterns degenerate, during subsequent stages. kn?del could be a segment polarity gene required for segment border maintenance in both trunk and appendages. Alternatively, it may have a more general role in tissue or organ maintenance.