Selection, integration, and conflict monitoring; assessing the nature and generality of prefrontal cognitive control mechanisms

Prefrontal cortex (PFC) supports flexible behavior by mediating cognitive control, though the elemental forms of control supported by PFC remain a central debate. Dorsolateral PFC (DLPFC) is thought to guide response selection under conditions of response conflict or, alternatively, may refresh recently active representations within working memory. Lateral frontopolar cortex (FPC) may also adjudicate response conflict, though others propose that FPC supports higher order control processes such as subgoaling and integration. Anterior cingulate cortex (ACC) is hypothesized to upregulate response selection by detecting response conflict; it remains unclear whether ACC functions generalize beyond monitoring response conflict. The present fMRI experiment directly tested these competing theories regarding the functional roles of DLPFC, FPC, and ACC. Results reveal dissociable control processes in PFC, with mid-DLPFC selectively mediating resolution of response conflict and FPC further mediating subgoaling/integration. ACC demonstrated a broad sensitivity to control demands, suggesting a generalized role in modulating cognitive control.     

Antilisterial Activity on Poultry Meat of Amylolysin, a Bacteriocin from Bacillus amyloliquefaciens GA1

This paper describes the production, the purification and the antilisterial activity of amylolysin, a novel bacteriocin from B. amyloliquefaciens GA1. The strain genome was first analysed using PCR techniques for the presence of gene clusters that direct the synthesis of characterised bacteriocins from B. amyloliquefaciens and the closely related B. subtilis. Our results suggest that amylolysin corresponds to a novel bacteriocin. The effect of amylolysin on the growth of different isolates of Listeria monocytogenes was evaluated in poultry meat during 21 days of storage at 4 °C. A potent antilisterial effect was observed for all the indicator strains tested, demonstrating that amylolysin is a novel bacteriocin that could be used as a food preservative.     

The role of HSP90 molecular chaperones in hepatocellular carcinoma

Misfolded proteins have enhanced formation of toxic oligomers and nonfunctional protein copies lead to recruiting wild-type protein types. Heat shock protein 90 (HSP90) is a molecular chaperone generated by cells that are involved in many cellular functions through regulation of folding and/or localization of large multi-protein complexes as well as client proteins. HSP90 can regulate a number of different cellular processes including cell proliferation, motility, angiogenesis, signal transduction, and adaptation to stress. HSP90 makes the mutated oncoproteins able to avoid misfolding and degradation and permits the malignant transformation. As a result, HSP90 is an important factor in several signaling pathways associated with tumorigenicity, therapy resistance, and inhibiting apoptosis. Clinically, the upregulation of HSP90 expression in hepatocellular carcinoma (HCC) is linked with advanced stages and inappropriate survival in cases suffering from this kind of cancer. The present review comprehensively assesses HSP90 functions and its possible usefulness as a potential diagnostic biomarker and therapeutic option for HCC.     

Double‐wavelet transform for multisubject task‐induced functional magnetic resonance imaging data

The goal of this article is to model multisubject task‐induced functional magnetic resonance imaging (fMRI) response among predefined regions of interest (ROIs) of the human brain. Conventional approaches to fMRI analysis only take into account temporal correlations, but do not rigorously model the underlying spatial correlation due to the complexity of estimating and inverting the high dimensional spatio‐temporal covariance matrix. Other spatio‐temporal model approaches estimate the covariance matrix with the assumption of stationary time series, which is not always feasible. To address these limitations, we propose a double‐wavelet approach for modeling the spatio‐temporal brain process. Working with wavelet coefficients simplifies temporal and spatial covariance structure because under regularity conditions, wavelet coefficients are approximately uncorrelated. Different wavelet functions were used to capture different correlation structures in the spatio‐temporal model. The main advantages of the wavelet approach are that it is scalable and that it deals with nonstationarity in brain signals. Simulation studies showed that our method could reduce false‐positive and false‐negative rates by taking into account spatial and temporal correlations simultaneously. We also applied our method to fMRI data to study activation in prespecified ROIs in the prefontal cortex. Data analysis showed that the result using the double‐wavelet approach was more consistent than the conventional approach when sample size decreased.     

Rostrolateral prefrontal cortex and individual differences in uncertainty-driven exploration

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Métastase splénique isolée métachrone d’un adénocarcinome colique

Isolated splenic metastases of colorectal cancers are very rare but possible even after several years of remission. We report the case of a 74-year-old man who developed isolated metachronous splenic metastasis of left colon cancer 5 years after the treatment of the primary tumor. Splenic metastasis was found by imaging examinations. The patient underwent splenectomy and the histological examination confirmed the metastatic nature of the splenic lesion. 18F-FDG PET allows both staging and resectability of these isolated metachronous splenic metastasis because a long-term survival can be achieved by splenectomy.     

Zinc protects HeLa-tat cells against free radical cytotoxicity induced by glucose

In the present study, we investigated the protective effect of zinc on the glucose-induced cytotoxicity in HeLa wild and HeLa-tat cells (30 and 20 mmol/l glucose, respectively). HeLa cells transfected with the protein Tat exhibit a lower antioxidant defense system. Incubation of HeLa wild and HeLa-tat cells with high glucose levels led to a rapid increase in generation of reactive oxygen species (ROS). As expected in the presence of high glucose concentrations, the viability was reduced for both cell lines. The redox status essentially regulated by thiol groups may play an important role in the apoptotic process. Thus, we developed a new method using the p-nitrophenyl disulfide to measure cytosolic thiol groups in intact cells. Cellular zinc was measured using inductively coupled plasma mass spectrometry. Intracellular thiol groups and intracellular zinc concentrations were significantly lower in HeLa cells cultured in hyperglycemic conditions, and their concentrations were significantly lower in HeLa-tat cells than in HeLa wild cells. However, the generation of ROS and the induction of apoptosis by a glucose specific mechanism were prevented by zinc (50 micromol/l) and the intracellular thiol groups and zinc concentrations significantly increased in both cell lines to become similar to the initial values. These results suggest that the glucose oxidation and its subsequent effects on the cells can be prevented by a biological antioxidant such as zinc.     

A protease-resistant prion protein isoform is present in urine of animals and humans affected with prion diseases.

Prion protein (PrP)(Sc), the only known component of the prion, is present mostly in the brains of animals and humans affected with prion diseases. We now show that a protease-resistant PrP isoform can also be detected in the urine of hamsters, cattle, and humans suffering from transmissible spongiform encephalopathies. Most important, this PrP isoform (UPrP(Sc)) was also found in the urine of hamsters inoculated with prions long before the appearance of clinical signs. Interestingly, intracerebrally inoculation of hamsters with UPrP(Sc) did not cause clinical signs of prion disease even after 270 days, suggesting it differs in its pathogenic properties from brain PrP(Sc). We propose that the detection of UPrP(Sc) can be used to diagnose humans and animals incubating prion diseases, as well as to increase our understanding on the metabolism of PrP(Sc) in vivo.     

Distribution of bacterial contamination in a teaching hospital in Tehran - a special focus on Staphylococcus aureus

There are documents that confirm the cycle of bacterial transmission between patients, staff, and the inanimate environment. The environment may have more effect on intensive care units (ICUs), because the patients who require intensive care have unstable clinical conditions and are more sensitive to infections. The aim of this study was to determine the prevalence of bacteria in air and inanimate surface in the ICUs and to compare the microbial levels to standard levels.Air and inanimate surface in the four ICUs of a teaching hospital underwent weekly surveillance by means of air sampler and swabs for a period of six-month. Total bacterial counts were evaluated onto trypticase soy agar and mannitol salt agar (MSA).A total of 725 samples [air (168) and inanimate surfaces (557)] were collected. The total mean ± SD CFU/m3 of airborne bacteria in all of the ICUs were 115.93 ± 48.04. The most common bacteria in air of the ICUs were Gram-positive cocci (84.2%). The total mean ± SD airborne of Staphylococcus aureus was 12.10±8.11 CFU/m3. The highest levels of S. aureus contamination were found in ventilators and bed ledges. More suitable disinfection of hospital environments and monthly rotation in utilization of the various disinfectant agents are needed for the prevention of airborne and inanimate transmission of S. aureus.