Reevaluating brain networks activated during mental imagery of finger movements using probabilistic Tensorial Independent Component Analysis (TICA)

The cerebral and cerebellar networks involved in execution and mental imagery of the same sequential finger movements performed with the non-dominant hand were assessed by 3T functional magnetic resonance imaging using multivariate model-free analysis. Eight right-handed healthy volunteers successively performed execution and mental imagery tasks (sequential thumb to fingers opposition). The same data were analyzed by using (1) the linear General Model (p < 0.05 corrected), and (2) probabilistic tensorial independent component analysis (TICA). TICA confirmed that overt movement execution and motor imagery share a common network mainly including: premotor, parietal, insular, temporal, cerebellar cortices and putamen. Motor imagery specifically and bilaterally recruited frontopolar, prefrontal, cingulate, medial insula, neocerebellar cortices and precuneus. Non-dominant hand movements induced bilateral brain and cerebellar activation. In comparison with GLM, TICA identified a more widespread and bilateral network especially during motor imagery. TICA revealed that motor imagery also recruits frontopolar precuneal and occipital cortices, rostral M1/S1 corresponding to the hand somatotopic representation, thalamus and cerebellar lobule VIII. TICA also showed concomitant activation of (1) a cerebello-thalamo-cortical network during motor execution, and (2) a control executive network during imagination. TICA therefore allows precise identification of the brain networks collaborating in the same performance. TICA constitutes a valuable tool to assess and improve detection of brain networks engaged in mental imagery in comparison with GLM.     

Eosin B as a novel antimalarial agent for drug-resistant Plasmodium falciparum

4',5'-Dibromo-2',7'-dinitrofluorescein, a red dye commonly referred to as eosin B, inhibits Toxoplasma gondii in both enzymatic and cell culture studies with a 50% inhibitory concentration (IC(50)) of 180 microM. As a non-active-site inhibitor of the bifunctional T. gondii dihydrofolate reductase-thymidylate synthase (DHFR-TS), eosin B offers a novel mechanism for inhibition of the parasitic folate biosynthesis pathway. In the present study, eosin B was further evaluated as a potential antiparasitic compound through in vitro and cell culture testing of its effects on Plasmodium falciparum. Our data revealed that eosin B is a highly selective, potent inhibitor of a variety of drug-resistant malarial strains, with an average IC(50) of 124 nM. Furthermore, there is no indication of cross-resistance with other clinically utilized compounds, suggesting that eosin B is acting via a novel mechanism. The antimalarial mode of action appears to be multifaceted and includes extensive damage to membranes, the alteration of intracellular organelles, and enzymatic inhibition not only of DHFR-TS but also of glutathione reductase and thioredoxin reductase. In addition, preliminary studies suggest that eosin B is also acting as a redox cycling compound. Overall, our data suggest that eosin B is an effective lead compound for the development of new, more effective antimalarial drugs.     

Prevalence and impact of pain on the quality of life of lung transplant recipients: a prospective observational study

STUDY OBJECTIVE: To study the prevalence and impact of pain on the quality of life (QOL) of lung transplant recipients. Design and patients: Prospective, observational, cross-sectional study. Ninety-six lung transplant recipients (> 3 months after transplantation) completed questionnaires measuring the severity and impact of pain (Brief Pain Inventory), anxiety (State Trait Anxiety Inventory), QOL (Short Form-36 version 2 [SF-36v2]), and depression (Beck Depression Inventory [BDI]). SETTING: University medical center lung transplant outpatient clinic. RESULTS: The prevalence of pain in lung transplant recipients was 49%. Patients with pain were older, more likely to have undergone unilateral lung transplantation (64% vs 40%, p = 0.03), and were more likely to have lung emphysema (55% vs 38%, p = 0.004). Only a pulmonary diagnosis of lung emphysema remained an independent predictor for postoperative pain in a logistic regression model. Average (+/- SD) score of the BDI was 9.6 +/- 7.8 and 5.8 +/- 5.8 (p = 0.005) for patients with and without pain, respectively. Patients with and without pain did not significantly differ in terms of anxiety. Pain-free patients had a significantly higher physical component score than patients with pain in the SF-36v2 (mean, 48.7 +/- 8.6 vs 38.6 +/- 9.8, p < 0.0001, respectively), while the mental component scores were not statistically different between the two groups. CONCLUSIONS: Lung transplant recipients have a high prevalence of pain. Patients with lung emphysema as their preoperative diagnosis are more likely to have pain. The occurrence of pain is associated with a decreased QOL in lung transplant recipients.     

Tonotopic control of auditory thalamus frequency tuning by reticular thalamic neurons

GABAergic cells of the thalamic reticular nucleus (TRN) can potentially exert strong control over transmission of information through thalamus to the cerebral cortex. Anatomical studies have shown that the reticulo-thalamic connections are spatially organized in the visual, somatosensory, and auditory systems. However, the issue of how inhibitory input from TRN controls the functional properties of thalamic relay cells and whether this control follows topographic rules remains largely unknown. Here we assessed the consequences of increasing or decreasing the activity of small ensembles of TRN neurons on the receptive field properties of medial geniculate (MG) neurons. For each MG cell, the frequency tuning curve and the rate-level function were tested before, during, and after microiontophoretic applications of GABA, or of glutamate, in the auditory sector of the TRN. For 66 MG cells tested during potent pharmacological control of TRN activity, group data did not reveal any significant effects. However, for a population of 20/66 cells (all but 1 recorded in the ventral, tonotopic, division), the breadth of tuning, the frequency selectivity and the acoustic threshold were significantly modified in the directions expected from removing, or reinforcing, a dominant inhibitory input onto MG cells. Such effects occurred only when the distance between the characteristic frequency of the recorded ventral MG cell and that of the TRN cells at the ejection site was <0.25 octaves; they never occurred for larger distances. This relationship indicates that the functional interactions between TRN cells and ventral MG cells rely on precise topographic connections.     

Iron overload induces BMP6 expression in the liver but not in the duodenum

Background

The bone morphogenetic protein BMP6 regulates hepcidin production by the liver. However, it is not yet known whether BMP6 derives from the liver itself or from other sources such as the small intestine, as has been recently suggested. This study was aimed at investigating the source of BMP6 further.

Design and Methods

We used three different strains of mice (C57BL/6, DBA/2, and 129/Sv) with iron overload induced either by an iron-enriched diet or by inactivation of the Hfe gene. We examined Bmp6 expression at both the mRNA (by quantitative PCR) and protein (by immunohistochemistry and Western blotting analyses) levels.

Results

We showed that iron overload induces Bmp6 mRNA expression in the liver but not in the duodenum of these mice. Bmp6 is also detected by immunohistochemistry in liver tissue sections of mice with iron overload induced either by an iron-enriched diet or by inactivation of the Hfe gene, but not in liver tissue sections from iron-loaded Bmp6-deficient mice. Bmp6 in the duodenum was below immunodetection threshold, thus confirming quantitative PCR data. Lack of specificity of available antibodies together with slight heterogeneity between 129 substrains may account for the differences with previously published data.

Conclusions

Our data strongly support the importance of liver BMP6 for regulation of iron metabolism. Indeed, they demonstrate that intestinal Bmp6 expression is modulated by iron neither at the mRNA nor at the protein level.     

Survival of patients with hepatobiliary tract and duodenal cancer sites in Germany and the United States in the early 21st century

Hepatobiliary tract cancers (HBTCs) are a heterogeneous group of cancers with high mortality. Because most of these cancers, with the exception of hepatocellular carcinoma (HCC), are rare, few data are available concerning the population level survival expectations of patients with HBTC. Here, we describe survival of patients with HBTC in Germany with comparison to survival in the US. Therefore, data were extracted from 12 databases in Germany and the Surveillance, Epidemiology and End Results (SEER13) database in the US. Period analysis and modeled period analysis were used to calculate 5‐year relative survival estimates for patients with HBTC diagnosed from 1997 to 2013. HCC was the most common HBTC in each database, accounting for over 1/3 of HBTC in Germany and about half of cases in the US. Overall age adjusted 5‐year relative survival for HBTC in 2006‐2013 was 19.1% in Germany and 20.6% in the US. Five‐year relative survival increased by 3.8% units in Germany and 4.5% units in the US between 2002–2005 and 2010–2013. Five‐year relative survival for individual types of HBTC ranged from 9.8% in Germany and 2.9% in the US for not otherwise specified biliary tract cancers to 44.4% and 50.1%, respectively, in Germany and the US for duodenal cancers. In conclusion, survival for HBTC remains poor in both Germany and the US, although a small increase in survival in the past decade was observed. Further work to find better treatment options for HBTC is needed to improve survival.