Delayed gastric emptying and reduced postprandial small bowel water content of equicaloric whole meal bread versus rice meals in healthy subjects: novel MRI insights

BACKGROUND/OBJECTIVES: Postprandial bloating is a common symptom in patients with functional gastrointestinal (GI) diseases. Whole meal bread (WMB) often aggravates such symptoms though the mechanisms are unclear. We used magnetic resonance imaging (MRI) to monitor the intragastric fate of a WMB meal (11% bran) compared to a rice pudding (RP) meal. SUBJECTS/METHODS: 12 healthy volunteers completed this randomised crossover study. They fasted overnight and after an initial MRI scan consumed a glass of orange juice with a 2267 kJ WMB or an equicaloric RP meal. Subjects underwent serial MRI scans every 45 min up to 270 min to assess gastric volumes and small bowel water content and completed a GI symptom questionnaire. RESULTS: The MRI intragastric appearance of the two meals was markedly different. The WMB meal formed a homogeneous dark bolus with brighter liquid signal surrounding it. The RP meal separated into an upper, liquid layer and a lower particulate layer allowing more rapid emptying of the liquid compared to solid phase (sieving). The WMB meal had longer gastric half emptying times (132±8 min) compared to the RP meal (104±7 min), P<0.008. The WMB meal was associated with markedly reduced MRI-visible small bowel free mobile water content compared to the RP meal, P<0.0001. CONCLUSIONS: WMB bread forms a homogeneous bolus in the stomach which inhibits gastric sieving and hence empties slower than the equicaloric rice meal. These properties may explain why wheat causes postprandial bloating and could be exploited to design foods which prolong satiation

Studies on the Biosynthesis of Psoralen and Bergapten in the Leaves of Ficus carica

With the aim of studying the biosynthesis of psoralen and bergapten, two furocoumarins present in the leaves of "Ficus carica" (Moraceae), the Authors, continuing preceding researchs on this topic, have fed the leaves with the following labelled precursors: 4′,5′-dihydropsoralen, 4′,5′-dihydrobergapten, 7-hydroxycoumarin, 5,7-dihydroxycoumarin and 5-methoxy-7-hydroxycoumarin. The results obtained indicate that all these substances are certain biogenetic precursors for psoralen and bergapten. On the basis of the results obtained the biosynthetic pathway of furocoumarins seems to involve first of all the formation of a coumarinic derivative 7-hydroxylated, then an isoprenylation reaction which leads to the formation of the hydrogenated furan ring, finally dehydrogenation of the 4′,5′-dihydrofurocoumarins to psoralen and bergapten

Studies on the Biosynthesis of Some Furocoumarins Present in Ruta graveolens

The biosynthesis of some furocoumarins present in Ruta graveolens has been studied administering labeled psoralen, xanthotoxin, rutaretin, marmesin and 7-hydroxycoumarin-derivatives. The results obtained indicate that the biosynthetic pathway involves not only psoralen, but also xanthotoxin and bergapten, by means of methoxylation or demethoxylation reactions. Moreover results achieved from administering rutaretin demonstrate that this substance is a new very effective natural precursor for xanthotoxin; in a parallel way marmesin is incorporated into psoralen. The reported results indicate that also at the stage of natural 4′,5′-dihydrofurocoumarins intermediates an interconversion can occur. Finally the essential role of umbelliferone in the biosynthesis of furocoumarins has been confirmed

Carotid artery stenting with filter protection in high-risk patients showing severe electroencephalographic alterations during carotid endarterectomy

Purpose: To describe the results and efficacy of stent treatment in patients with carotid stenosis who had aborted carotid endarterectomy procedures due to the appearance of severe electroencephalographic (EEG) alterations. Methods: A retrospective study was conducted of 18 patients (11 men; mean age 72 years, range 62–84) with symptomatic high-grade carotid artery stenoses ( 70%) who experienced severe EEG alterations during carotid endarterectomy, causing the procedure to be aborted. Twelve patients had shown no hemodynamic alterations during preoperative transcranial Doppler evaluation after external compression of the common carotid artery; the remaining 6 could not be evaluated. The patients were referred for carotid artery stenting (CAS); 7 had contralateral internal carotid artery stenosis and 5 had contralateral occlusion. Endovascular intervention was carried out using standard techniques under filter protection. Follow-up was scheduled at 3, 6, and 12 months. Results: All patients were successfully treated without immediate complications. The EEG did not display any significant alterations during the endovascular procedure. Mean followup was 43 months. Magnetic resonance imaging at 6 months showed no signs of cerebral ischemia. Color Doppler ultrasound imaging documented normal stent patency in all patients. Conclusion: Patients with symptomatic severe carotid stenosis ( 70%) who are considered at risk due to the appearance of severe EEG alterations during surgical treatment may benefit from CAS with respect to both major and minor complications. Larger studies are needed to confirm these findings. J Endovasc Ther 2006;13:451–456 Key words: carotid endarterectomy, carotid artery, stenosis, electroencephalography, cerebral ischemia, carotid angioplasty, sten

Increased cortical excitability after selective REM sleep deprivation in healthy humans: a transcranial magnetic stimulation study

REM sleep has antiepileptogenic properties whereas, its loss is known to have a proconvulsive role. However, the mechanisms underlying the proepileptogenic effects of REM sleep deprivation are yet not fully understood. The aim of our study was to evaluate the effects of selective REM sleep deprivation (SRD) on cortical excitability in healthy subjects by means of transcranial magnetic stimulation (TMS)

The Parkinson-related E193K LRRK2 variant impacts neuronal vesicles dynamics through perturbed protein interactions

The Leucine-Rich Repeat Kinase 2 (LRRK2) is a complex protein, expressed in neurons and implicated in Parkinson disease (PD). LRRK2 contains a dual enzymatic activity and several structural domains that constitute a versatile platform for multiple protein interactions at the synapses. In this study, we characterize the functional role of the N-terminal Armadillo repeats domain of LRRK2 and the impact on synaptic vesicle (SV) dynamics of a novel variant, E193K, harboured within this domain and identified in an Italian family affected by PD. Using a genetically encoded sensor of recycling, synaptopHluorine, and total internal reflection fluorescence microscopy, we visualized SV trafficking in the N2A neuroblastoma cells expressing the wild type LRRK2 protein, a mutant lacking the Armadillo domain (\u394N LRRK2) or the E193K variant. We found that expression of the \u394N construct increased the frequency and the amplitude of spontaneous synaptic events. A similar phenotype was detected in the presence of the E193K variant, suggesting that this mutation behaves as a loss-of-function mutation. A domain-based pulldown approach demonstrated that the LRRK2 N-terminus binds to cytoskeletal (\u3b2-actin and \u3b1-tubulin) and SV (synapsin I) proteins and the E193K substitution alters strength and quality of LRRK2 interactions. The results support a role of the Armadillo domain in interaction with synaptic proteins and suggest that the E193K mutation affects LRRK2 function via perturbation of its physiological network of interactors, resulting in impaired vesicular trafficking. These findings may have important implications for understanding the role of LRRK2 at the synapses and the pathophysiological mechanism for LRRK2-linked disease

The Estimation of Cortical Activity for Brain-Computer Interface: Applications in a Domotic Context

In order to analyze whether the use of the cortical activity, estimated from noninvasive EEG recordings, could be useful to detect mental states related to the imagination of limb movements, we estimate cortical activity from high-resolution EEG recordings in a group of healthy subjects by using realistic head models. Such cortical activity was estimated in region of interest associated with the subject's Brodmann areas by using a depth-weighted minimum norm technique. Results showed that the use of the cortical-estimated activity instead of the unprocessed EEG improves the recognition of the mental states associated to the limb movement imagination in the group of normal subjects. The BCI methodology presented here has been used in a group of disabled patients in order to give them a suitable control of several electronic devices disposed in a three-room environment devoted to the neurorehabilitation. Four of six patients were able to control several electronic devices in this domotic context with the BCI system

The Role of the Mucus Barrier in Digestion

Mucus forms a protective layer across a variety of epithelial surfaces. In the gastrointestinal (GI) tract, the barrier has to permit the uptake of nutrients, while excluding potential hazards, such as pathogenic bacteria. In this short review article, we look at recent literature on the structure, location, and properties of the mammalian intestinal secreted mucins and the mucus layer they form over a wide range of length scales. In particular, we look at the structure of the gel-forming glycoprotein MUC2, the primary intestinal secreted mucin, and the influence this has on the properties of the mucus layer. We show that, even at the level of the protein backbone, MUC2 is highly heterogeneous and that this is reflected in the networks it forms. It is evident that a combination of charge and pore size determines what can diffuse through the layer to the underlying gut epithelium. This information is important for the targeted delivery of bioactive molecules, including nutrients and pharmaceuticals, and for understanding how GI health is maintained