• Energy Research
• Open Access close
• Closed Access close
• GB close
• IN close
• Neuroinformatics close

AbstractA pulse sequence was implemented to observe the magnetization transfer (MT) effect on metabolites, water, and macromolecules in human frontal lobes in vivo at 1.5 Tesla. Signals were compared following the application of three hard pulses of 0.745 μT amplitude, applied at frequency offsets of either 2500 Hz or 30 kHz, preceding a conventional point‐resolved spectroscopy (PRESS)‐localized acquisition with an echo time (TE) of 30 ms and repetition time (TR) of 3 s. This gave an MT effect on water in vivo of 46%, while direct saturation by the MT pulses at 2.5 kHz offset was confirmed to be under 4% for all metabolites. We observed significant MT saturation in vivo for N‐acetylated compounds, choline (Cho), myo‐inositol, and lactate (Lac); a trend of an effect on glutamate + glutamine (Glx); and the typically observed effect on creatine (Cr). No significant MT effect was seen on the macromolecule signal, which was observed using metabolite nulling. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.

Neuroimaging studies have demonstrated gray matter (GM) volume abnormalities in substance users. While the majority of substance users are polysubstance users, very little is known about the relation between GM volume abnormalities and polysubstance use.In this study we assessed the relation between GM volume, and the use of alcohol, tobacco, cocaine and cannabis as well as the total number of substances used, in a sample of 169 males: 15 non-substance users, 89 moderate drinkers, 27 moderate drinkers who also smoke tobacco, 13 moderate drinkers who also smoke tobacco and use cocaine, 10 heavy drinkers who smoke tobacco and use cocaine and 15 heavy drinkers who smoke tobacco, cannabis and use cocaine.Regression analyses showed that there was a negative relation between the number of substances used and volume of the dorsal medial prefrontal cortex (mPFC) and the ventral mPFC. Without controlling for the use of other substances, the volume of the dorsal mPFC was negatively associated with the use of alcohol, tobacco, and cocaine. After controlling for the use of other substances, a negative relation was found between tobacco and cocaine and volume of the thalami and ventrolateral PFC, respectively.These findings indicate that mPFC alterations may not be substance-specific, but rather related to the number of substances used, whereas, thalamic and ventrolateral PFC pathology is specifically associated with tobacco and cocaine use, respectively. These findings are important, as the differential alterations in GM volume may underlie different cognitive deficits associated with substance use disorders.

We report a case of bispectral index (BIS) falling to zero during absolute alcohol embolization of an intracranial arteriovenous malformation (AVM) under anesthesia. This case highlights the unusual effect of a therapeutic dose of parenteral alcohol on the central nervous system using BIS monitoring.A 29-yr-old male with a left parieto-occipital arteriovenous malformation underwent neuroendovascular embolization under general anesthesia. During injection of absolute alcohol injection into the AVM nidus, the patient developed hypertension and tachycardia coincident with a profound and sustained reduction of BIS values to zero, despite a stable level of anesthesia. Immediate angiography revealed no evidence of hemorrhage or new changes in the patient's cerebral vasculature. Post-procedure, the patient remained drowsy for several hours with signs of alcohol intoxication. He had full neurological recovery.In the presence of normal cerebral angiographic findings, suppression of BIS values may serve as an early indicator of CNS responses to intracranial injection of absolute alcohol for embolization of an arteriovenous malformation.

The aggregation of gel-filtered human platelets induced by A23187 is very sensitive to inhibition by ethanol. Similarly when platelets preloaded with [3H]5-hydroxytryptamine ([3H]5HT) are studied in a superfusion system under conditions where aggregation is likely (high platelet density, presence of Ca2+) the rate of release of [3H]5HT induced by A23187 is reduced by the presence of ethanol. However when platelet aggregation is less likely (low platelet density, absence of Ca2+) ethanol does not reduce the rate of [3H]5HT efflux induced by A23187 in superfused platelets. In addition, in contrast to the effects of ethanol on platelet aggregation, the transformation of human red cells to echinocytes induced by A23187 is accelerated by the presence of ethanol. Similarly the increased efflux of 3H from superfused rat striatal slices preloaded with [3H]dopamine which is produced by A23187 is potentiated by ethanol. It is concluded that the inhibitory effect of ethanol on the action of A23187 may be confined to platelet aggregation. This may be because the mechanisms of action of either A23187 or ethanol on platelet aggregation differ from those on other cell functions.

Inositol monophosphatase can be modified at two sites by pyrene maleimide. These sites have been identified as Cys141 and Cys218. Stoichiometric addition of pyrene maleimide allows the sole modification of Cys218. The fluorescence of the pyrene moiety on the modified protein can be excited directly or by resonance energy transfer. The fluorescence properties of the pyrene group on Cys218 allows the interaction of ligands with the enzyme to be monitored. This feature has allowed dissociation constants for various metal ions to be determined and allowed the formation of various enzyme/ligand complexes to be observed. These studies have demonstrated that Mg2+ is required to support Pi binding and that Li+ interacts with a post‐catalytic complex which is only formed in the forward reaction.

The effects of a mega dose of ascorbic acid (AA) on alcohol induced peroxidative damages were investigated in guinea pigs. In the present study, four groups of male guinea pigs were maintained for 30 days as follows. (1) Control group (1 mg AA/100 g body wt); (2) Ethanol group (1 mg AA/100 g body wt. + 9 g ethanol/kg body wt); (3) AA group (25 mg AA/100 g body wt); (4) AA + ethanol group (25 mg AA/100 g body wt. + 9 g ethanol/kg). Results revealed that alcohol induced significant lipid peroxidation, since the lipid peroxidation products malondialdehyde (MDA), hydroperoxides and conjugated dienes were elevated. The activities of scavenging enzymes superoxide dismutase (SOD), catalase were reduced. However, supplementation of AA along with alcohol reduced the lipid peroxidation products in the liver and enhanced the activities of scavenging enzymes. Activities of glutathione peroxidase and reductase were also greater in guinea pigs given alcohol + AA in comparison with those given alcohol alone. Administration of ascorbic acid also reduced the activity of gamma-glutamyl transpeptidase (GGT), the marker enzyme of alcohol induced toxicity. The vitamin E level, which was reduced by alcohol intake, was raised by the co-administration of AA and alcohol. These studies suggest that a mega dose of AA helps in the prevention of alcohol induced oxidative stress by enhancing the antioxidant capacity and also by reducing the lipid peroxidation products.

The storage and transport of gases in coal is of tremendous importance in the utilisation of coalbeds, and in particular the recovery of methane. There is also increasing interest in the use of coal mines as sites for carbon dioxide sequestration to alleviate the potentially harmful effects of global warming. This paper demonstrates the use of magnetic resonance imaging to investigate the spatiotemporal dynamics of gas transport in coal. The presence of significant structural heterogeneities in the coal was observed. Dynamical effects displayed a broad range of time constants ranging from minutes to days.

Phospholipase C (PLC) activity was measured by the incorporation of [3H]-inositol into lipids and by the breakdown of [3H]-inositol-labelled phosphatidylinositols (PI) and polyphosphatidylinositols (PPI) to [3H]-inositol phosphates; phospholipase A2 (PLA2) activity by the breakdown of [3H]oleic acid-labelled phosphatidylcholine [( 3H]PC) to [3H]oleic acid and the enzymes of phospholipid base exchange (PLBE) by the incorporation of [14C]serine into membrane lipids. The activities of these enzymes in rat brain preparations were all increased by procedures which increase intracellular Ca2+, and were all inhibited to a varying extent by the presence of ethanol, 50 mM, in vitro. In contrast, the activities of PLA2 and PLBE enzymes were markedly increased in preparations from animals which had received ethanol chronically in vivo. Similarly, although the basal activity of PLC was only slightly increased in such preparations, depolarization induced the breakdown of a significantly greater fraction of radiolabelled PI than that which was obtained in control preparations. The results suggest compensatory alterations in the activity of Ca2+-activated enzymes of phospholipid metabolism in brain tissue during the continued presence of ethanol in vivo.

Chronic ethanol exposure causes neurotoxicity and long-term learning and memory impairment along with hippocampal and frontal cortical dysfunction. Flavonoids possess antioxidant and anti-inflammatory properties believed to be contributory factors in reversing cognitive decline. 6-Methoxyflavone (6-MOF), a flavonoid occurring naturally in medicinal plants, has been reported to instigate neuroprotection by reversing cisplatin-induced hyperalgesia and allodynia. Consequently, this study was designed to investigate 6-MOF activity in models of chronic ethanol-induced cognitive impairment along with neurochemical correlates.Mice were given ethanol orally (2.0 g/kg daily) for 24 days plus either saline, 6-MOF (25-75mg/kg) or donepezil (4mg/kg) and then ethanol was withdrawn for the next 6 days. Animals were subsequently assessed for their cognitive performance in several models on days 1, 12, and 24, during abstinence (Day-26) and on the 7th day of the washout period. Following behavioral assessment, post-mortem dopamine, noradrenaline and vitamin C concentrations were quantified in the frontal cortex, hippocampus and striatum, using HPLC with UV detection.Chronic ethanol treatment suppressed locomotor activity and impaired cognitive tasks, which included novel object recognition, performance in the Morris water maze as well as the Y-maze, socialization and nest-building behavior throughout the protocol and during withdrawal. These behavioral deficits were at least partially restored by the co-administration of 6-MOF or donepezil with ethanol as were ethanol-induced deficits in frontal cortical and hippocampal dopamine plus noradrenaline, together with striatal dopamine. 6-MOF co-administration with ethanol also modestly restored striatal vitamin C levels.It is postulated that, apart from donepezil, 6-MOF may be useful not only in the treatment of ethanol withdrawal severity but also in the management of chronic ethanol withdrawal induced cognitive impairment.