Ultrastructural changes of the human pancreas in acute shock

Human pancreas tissue was studied electron microscopically during various stages of shock. The subcellular changes of exocrine pancreas affect in particular endoplasmic reticulum (ER), mitochondria, cytoplasm, and nuclei. Alterations correlate with duration and severity of shock, causing cell death in prolonged or severe manifestations of shock. This is obviously due to release of enzymes from zymogen granules; the ensuing damage cannot be distinguished from autodigestive pancreatitis. Lesions of exocrine pancreas cells are of multifactorial origin, arising from general shock-induced hypoxia, but also from local ischemia due to disturbed microcirculation provoking intravasal coagulation. Beyond these main causes, intracellular disorders of metabolism, obstruction of lymph drainage, and nervous factors may be of influence. As the cases surveyed in this paper had no fatal outcome - except for one patient - the changes described can be defined as non-lethal or as reversible.     

Meckel''s Cave Tuberculoma with Unusual Infratemporal Extension

The authors describe a rare case of intracranial tuberculoma of the Meckel's cave and cavernous sinus with extension into the infratemporal fossa causing widening of the foramen ovale and adjacent bone destruction. The rarity of the lesion and the unusual extension of the lesion are presented with a brief review of literature.     

Decreased long-range temporal correlations in the resting-state functional magnetic resonance imaging blood-oxygen-level-dependent signal reflect motor sequence learning up to 2 weeks following training

Decreased long-range temporal correlations (LRTC) in brain signals can be used to measure cognitive effort during task execution. Here, we examined how learning a motor sequence affects long-range temporal memory within resting-state functional magnetic resonance imaging signal. Using the Hurst exponent (HE), we estimated voxel-wise LRTC and assessed changes over 5 consecutive days of training, followed by a retention scan 12 days later. The experimental group learned a complex visuomotor sequence while a complementary control group performed tightly matched movements. An interaction analysis revealed that HE decreases were specific to the complex sequence and occurred in well-known motor sequence learning associated regions including left supplementary motor area, left premotor cortex, left M1, left pars opercularis, bilateral thalamus, and right striatum. Five regions exhibited moderate to strong negative correlations with overall behavioral performance improvements. Following learning, HE values returned to pretraining levels in some regions, whereas in others, they remained decreased even 2 weeks after training. Our study presents new evidence of HE's possible relevance for functional plasticity during the resting-state and suggests that a cortical subset of sequence-specific regions may continue to represent a functional signature of learning reflected in decreased long-range temporal dependence after a period of inactivity.     

Synthesis and human beta-adrenoceptor activity of 1-(3,5-diiodo-4- methoxybenzyl)-1,2,3,4-tetrahydroisoquinolin-6-ol derivatives in vitro

Trimetoquinol (1, TMQ) is a potent nonselective beta-adrenergic receptor (AR) agonist and a thromboxane A(2)/prostaglandin endoperoxide (TP) receptor antagonist, while 3',5'-diiodo-TMQ (2) exhibits beta(3)-AR selectivity. In search of selective beta(3)-AR agonists as potential drugs for the treatment of human obesity and type II diabetes mellitus, a series of 1-(3, 5-diiodo-4-methoxybenzyl)-1,2,3,4-tetrahydroisoquinolin-6-ols has been prepared and evaluated for their biological activities at human beta(1)-, beta(2)-, and beta(3)-ARs expressed in Chinese hamster ovary (CHO) cells. The compounds have been synthesized by the Bischler-Napieralski cyclization of corresponding amides followed by NaBH(4) reduction, and the halogens in the aromatic ring A were introduced by direct halogenation of protected compound 11. Whereas halogen substitution in ring A reduced either potency or intrinsic activity on beta(3)-AR, the non-halogen-substituted compounds 8 and 10 were potent, selective, nearly full agonists for beta(3)-AR.     

A novel method for reliable and fast extraction of neuronal EEG/MEG oscillations on the basis of spatio-spectral decomposition

Neuronal oscillations have been shown to underlie various cognitive, perceptual and motor functions in the brain. However, studying these oscillations is notoriously difficult with EEG/MEG recordings due to a massive overlap of activity from multiple sources and also due to the strong background noise. Here we present a novel method for the reliable and fast extraction of neuronal oscillations from multi-channel EEG/MEG/LFP recordings. The method is based on a linear decomposition of recordings: it maximizes the signal power at a peak frequency while simultaneously minimizing it at the neighboring, surrounding frequency bins. Such procedure leads to the optimization of signal-to-noise ratio and allows extraction of components with a characteristic "peaky" spectral profile, which is typical for oscillatory processes. We refer to this method as spatio-spectral decomposition (SSD). Our simulations demonstrate that the method allows extraction of oscillatory signals even with a signal-to-noise ratio as low as 1:10. The SSD also outperformed conventional approaches based on independent component analysis. Using real EEG data we also show that SSD allows extraction of neuronal oscillations (e.g., in alpha frequency range) with high signal-to-noise ratio and with the spatial patterns corresponding to central and occipito-parietal sources. Importantly, running time for SSD is only a few milliseconds, which clearly distinguishes it from other extraction techniques usually requiring minutes or even hours of computational time. Due to the high accuracy and speed, we suggest that SSD can be used as a reliable method for the extraction of neuronal oscillations from multi-channel electrophysiological recordings.