Intraluminal chondrosarcoma leading to occlusion of the brachiocephalic trunk

A 62-year-old female patient was admitted with temporary neurological symptoms. CT scan revealed occlusion of the brachiocephalic trunk by an intraluminal mass suspicious for a thrombus and extending into the ascending aorta. The patient underwent aortic arch replacement with reinsertion of the supraaortic vessels. A 5 × 3 × 4 cm large mass was found in the aorta which had obviously caused occlusion of the brachiocephalic trunk. The patient had an uneventful postoperative recovery and follow-up imaging showed no pathological findings. Histopathological examination revealed inhomogeneous chondroid tissue such as that found in a G2 grade bone chondrosarcoma.

Neuronal correlates of affective theory of mind in schizophrenia out-patients: evidence for a baseline deficit

BACKGROUND

Schizophrenia out-patients have deficits in affective theory of mind (ToM) but also on more basal levels of social cognition, such as the processing of neutral and emotional expressions. These deficits are associated with changes in brain activation in the amygdala and the superior temporal sulcus (STS). However, until now there have been no studies that examined these different levels of social cognition and their neurobiological underpinnings in patients within one design.

METHOD

Sixteen medicated schizophrenia out-patients and 16 matched healthy controls were studied with functional magnetic resonance imaging (fMRI) during a social cognition task that allows the investigation of affective ToM (aToM), emotion recognition and the processing of neutral facial expressions.

RESULTS

Patients showed a deficit in emotion recognition and a more prominent deficit in aToM. The performance in aToM and in emotion recognition was correlated in the control group but not in the schizophrenia group. Region-of-interest analysis of functional brain imaging data revealed no difference between groups during aToM, but a hyperactivation in the schizophrenia group in the left amygdala and right STS during emotion recognition and the processing of neutral facial expressions.

CONCLUSIONS

The results indicate that schizophrenia out-patients have deficits at several levels of social cognition and provide the first evidence that deficits on higher-order social cognitive processes in schizophrenia may be traced back to an aberrant processing of faces per se.

Subunit-dependent modulation of kainate receptors by muscarinic acetylcholine receptors

Interactions between cholinergic and glutamatergic neurotransmitter systems influence synaptic transmission and plasticity. While previous studies have examined cross-talk between acetylcholine (ACh) and NMDA or AMPA receptors, little is known about the effect of ACh on kainate receptors (KARs). We show that stimulation of m1 or m3 muscarinic ACh receptors (mAChRs) for 2min potentiates recombinant KAR currents in a long lasting fashion. Muscarinic AChR activation potentiates heteromeric GluK2/GluK4 and GluK2/GluK5 receptors, but not homomeric GluK2 receptors. In hippocampal slices kainate potentiates mossy fiber axon excitability. Transient mAChR activation enhances this action of kainate, suggesting a novel mechanism through which acetylcholine could modulate synaptic transmission in the hippocampus. KAR over-activation has been implicated in excitotoxic cell death. To establish the functional significance of the interaction between mAChRs and KARs we examined the effect of mAChR activation on KAR-mediated excitotoxicity. We find that during pharmacological blockade of NMDA and AMPA receptors, KAR activation with AMPA produces significant cell death in primary cortical culture. Concanavalin A (Con A), which selectively blocks KAR desensitization, markedly increases this KAR-mediated neurotoxicity. Brief activation of mAChRs with pilocarpine significantly enhances KAR-mediated excitotoxicity both in the presence and absence of Con A. We conclude that KARs are modulated in a subunit dependent manner by mAChRs. We suggest that ACh may induce long lasting alterations in neuronal excitability and enhance excitotoxicity in part by potentiating KAR function.

Lipofuscin-like pigments in the rat heart during early postnatal development: effect of selenium supplementation

The aim of the study was to characterize a) the lipofuscin-like pigment (LFP) accumulation (an indicator of ROS production) in the rat heart during early postnatal period and b) possible antioxidative role of selenium. Experimental animals received Na(2)SeO(3) in drinking water during gravidity and up to day 15 post partum. Two fluorophores of LFP in the hearts of 1-, 4-, 7- and 15-day-old rats were evaluated by fluorescent analysis. The highest level of heart/body weight ratio in control rats was observed on day 4, in the Se-supplemented rats on day 7. Cardiac LFP content in controls increased from postnatal day 4, in the hearts of Se-supplemented rats the LFP content increased already from day 1. As compared with the Se-supplemented group the LFP content of control hearts was significantly higher on day 1 but significantly lower on day 4. LFP concentration in control hearts decreased from postnatal day 1 to 4; this decrease was followed by significant increase until day 7 and decrease to day 15. LFP concentration in the Se-supplemented hearts was the highest on postnatal day 7; it differed from controls on day 1 and 4. Significant changes of LFP suggest an important role of ROS during critical ontogenetic period.

Hypercapnia attenuates hypoxic pulmonary hypertension by inhibiting lung radical injury

Chronic lung hypoxia results in hypoxic pulmonary hypertension. Concomitant chronic hypercapnia partly inhibits the effect of hypoxia on pulmonary vasculature. Adult male rats exposed to 3 weeks hypoxia (Fi(02)=0.1) combined with hypercapnia (Fi(C02)=0.04-0.05) had lower pulmonary arterial blood pressure, increased weight of the right heart ventricle, and less pronounced structural remodeling of the peripheral pulmonary arteries compared with rats exposed only to chronic hypoxia (Fi(02)=0.1). According to our hypothesis, hypoxic pulmonary hypertension is triggered by hypoxic injury to the walls of the peripheral pulmonary arteries. Hypercapnia inhibits release of both oxygen radicals and nitric oxide at the beginning of exposure to the hypoxic environment. The plasma concentration of nitrotyrosine, the marker of peroxynitrite activity, is lower in hypoxic rats exposed to hypercapnia than in those exposed to hypoxia alone. Hypercapnia blunts hypoxia-induced collagenolysis in the walls of prealveolar pulmonary arteries. We conclude that hypercapnia inhibits the development of hypoxic pulmonary hypertension by the inhibition of radical injury to the walls of peripheral pulmonary arteries.

Comparative gene expression profiling of post-natal and post-pneumonectomy lung growth

Although increasing numbers of patients suffer from chronic destructive lung diseases, there are no effective therapeutic options apart from transplantation. Understanding the mechanisms of physiological and regenerative alveolar septation is prerequisite for the development of regenerative therapies for the lung. We compared lung gene expression in the phase of induction of post-natal and post-pneumonectomy alveolarisation to identify regulatory genes involved in both processes. We performed genome-wide microarray screenings of newborn and pneumonectomised mouse lungs 1 and 3 days after birth or surgery. Selected candidates were validated by real-time PCR, Western blot and in situ hybridisation. We found 58 genes to be regulated in both models with 40 candidates being changed likewise. Many of these genes participated in growth and differentiation processes. Additionally, immune system, structural molecules, respiratory chain, signal transduction and metabolism were involved. Some candidates were not yet linked to specific functions. The highest regulatory concordance was observed for various isoforms of (pro-)collagen molecules, elastin and the elastin-associated protein fibrillin1 being corporately upregulated. Our findings do not definitively support a common regulating mechanism for induction of post-natal and adult alveolarisation, but some candidates in the intersection of both models are promising for further investigations.

HYPOXIA AND REOXYGENATION INCREASE H 2 O 2 PRODUCTION IN RATS

To test the effect of transition from sustained hypoxia to normoxia on production of reactive oxygen species (ROS) in lungs, the authors measured hydrogen peroxide (H(2)O(2)) output in the expired air of rats breathing hypoxic, normoxic, and hyperoxic gas mixtures at the end of exposure to 72 hours of hypoxia. Twenty-one male Wistar rats (200 to 280 g) were randomly assigned to 1 of 3 groups. First two groups (experimental) were kept for 3 days in normobaric hypoxic chamber (F(1)O(2) 0.1), rats of the third group (controls) breathed air. The rats were then anesthetized, intubated, placed in the plethysmograph, and their ventilation measured. Two periods of exhaled breath condensate (EBC) collection, each lasting 1 hour, were then performed to assay H(2)O(2) output. The controls breathed during both samplings air, the first experimental group breathed during first sampling period hypoxic mixture (F(1)O(2) 0.1; SH-H measurement) and then, during second period, air (SH-H-A measurement), the second experimental group breathed first air (SH-A measurement) and then hyperoxic mixture (F(1)O(2) 1.0; SH-A-O(2) measurement). Concentration of H(2)O(2) in the EBC was assayed by chemiluminescence. H(2)O(2) production in the control group was low and similar in both measurements (20+/-10 and 13+/-5 pmol/h, mean+/-SEM). Exposure to 72 hours of hypoxia increased the H(2)O(2) production to 105+/-18 pmol/h (SH-H). Transition from hypoxia to normoxia resulted in an increase in the H(2)O(2) production (SH-A 421+/-24 pmol/h, and SH-H-A 366+/-19 pmol/h). Following transition from air breathing to hyperoxia did not affect the H(2)O(2) production (SH-A-O(2) 373+/-25 pmol/h). The results showed that sustained hypoxia and transition from sustained hypoxia to normoxia increased H(2)O(2) formation in the lungs.

Treatment with clomethiazole is associated with lower rates of premature discharge during alcohol withdrawal

INTRODUCTION

Numerous investigations have shown that premature discharge against medical advice from alcohol detoxification treatment is associated with poor outcome. The aim of the present study was to assess the risk of different possible influencing factors.

PATIENTS AND METHOD

168 in-patients admitted for detoxification treatment were included in the study. All patients were detoxified using clome-thiazole and/or carbamazepine in individual, symptom-triggered dosages. Possible influencing factors were recorded using a standardised interview.

RESULTS

Cox regression revealed a lower risk of premature discharge being significantly asso-ciated with few preceding withdrawals, intoxication at admission and treatment with clomethiazole. Kaplan-Meier survival statistics showed a significantly lower risk only for being treated with clomethiazole (premature discharge until day 7: chi2=25.07; p<0.001; premature discharge until day 14: chi2=5.19; p=0.023). Other included demographic factors like daily intake of ethanol before admission, duration of alcohol dependence, age or smoking status were not associated with the risk of premature discharge.

DISCUSSION

The present findings show that pharmacotherapy with clomethiazole may positively influence the risk of premature discharge. This might be a consequence of the psychoactive properties of the drug which leads to positive reinforcement.

Redox regulation of proliferation of lens epithelial cells in culture

Both oxidants and antioxidants have been shown to modulate cell proliferation. We studied the effects of hydrogen peroxide and two antioxidants on the rate of proliferation of lens epithelial cells in culture. Hydrogen peroxide at concentrations higher than 32 microM caused a significant inhibition of proliferation. However, in the concentration range of 0.01-0.5 microM, hydrogen peroxide stimulated the rate of proliferation. The effect of hydrogen peroxide was dependent on the amount of cells in an individual culture well, indicating decomposition of hydrogen peroxide by cellular enzymes. In order to eliminate the possibility of decomposition of the dose of hydrogen peroxide given as a bolus, we induced continual production of hydrogen peroxide by adding glucose oxidase to the incubation medium. We found that hydrogen peroxide, generated by 1-50 microU x ml(-1) of glucose oxidase significantly increased the rate of cell proliferation. This effect was most apparent at the beginning of the exponential phase of cellular growth. Glucose oxidase alone (100-500 microU x ml(-1)) did not produce any effect. The effects of pro-oxidative hydrogen peroxide were compared with the effects of two biologically important antioxidants, alpha-tocopherol and retinol. Both antioxidants completely inhibited proliferation at concentrations of 30 microM and higher. In contrast to retinol, the effect of alpha-tocopherol was dependent on the amount of cells, indicating cellular decomposition of alpha-tocopherol. The results document the possibility of redox regulation of cellular proliferation at physiologically relevant reactant concentrations.

Quantitative tube model for semiflexible polymer solutions

We develop an analytical and quantitative theory of the tube model concept for entangled networks of semiflexible polymers. The absolute value of the tube diameter L perpendicular is derived as a function of the polymers' persistence length lp and mesh size xi of the network. To leading order, we find L perpendicular = 0.31xi 6/5 lp (-1/5) , which is consistent with known asymptotic scaling laws. Additionally, our theory provides finite-length corrections that can account for effects of polydispersity. We support our analytical studies by extensive computer simulations. These allow to verify assumptions essential to our theoretical description and provide an excellent agreement with the analytically calculated tube diameter. Furthermore, we present simulation data for the distribution function of tube widths in the network.