Disseminated necrotizing leukoencephalopathy following low-dose oral methotrexate

Leukoencephalopathy is a recognized complication with intrathecal or intravenous methotrexate (MTX). We report a 59-year-old lady who developed MTX leukoencephalopathy with long-term low-dose oral MTX. She developed posterior leukoencephalopathy (PLE) that initially was reversible on discontinuation of oral MTX. Four months later, she developed disseminated necrotizing leukoencephalopathy (DNL), and was left with devastating neurological deficits. The sequential conventional magnetic resonance imaging (MRI), diffusion weighted imaging (DWI), MR perfusion (MRP) and MR spectroscopic (MRS) changes are highlighted in this report. MRP and MRS showed more wide spread abnormalities than DWI. Stereotactic biopsy from the lesion revealed demyelination with macrophagic infiltration, pericapillary lymphomononuclear aggregation, fibrinoid changes in the capillaries and neovascularization. Of the two cases of PLE with oral MTX reported in literature, one reversed clinically and radiologically with the discontinuation of MTX. To the best of our knowledge, this is the first reported case of DNL following oral MTX in the world literature.

Differential protein expression profiles in the hippocampus of human alcoholics

Mild to severe cognitive impairments are frequently observed symptoms in chronic alcoholics. Decline of cognitive function significantly affects patients' recovery process and prognosis. The hippocampal region is sensitive to the effects of alcohol and it has been suggested that alcohol-induced hippocampal damage and/or changes in neuronal circuitry play an important role in generating these symptoms. Although various hypotheses have been proposed, molecular mechanisms underlying these alterations in the hippocampus are largely unknown. In the present study, we employed a 2DE-based proteomics approach to compare the protein expression profiles of the hippocampus in human alcoholic and healthy control brains. In the alcoholic hippocampus, 20 protein spots were found to be differentially regulated, 2 increased and 18 decreased. Seventeen proteins were identified using mass spectroscopy and were subcategorized into three energy metabolic proteins, six protein metabolic proteins, four signalling proteins, two oxidative stress-related proteins, one vesicle trafficking protein and one cytoskeletal protein. Some of these proteins have been previously implicated in alcohol-induced brain pathology. Based upon the results, several hypotheses were generated to explain the mechanisms underlying possible functional and/or structural alterations induced by chronic alcohol use in this brain region.

Changes in brain functional activation during resting and locomotor states after unilateral nigrostriatal damage in rats

To evaluate functional neuronal compensation after partial damage to the nigrostriatal system, we lesioned rats unilaterally in the striatum with 6-hydroxydopamine. Five weeks later, cerebral perfusion was mapped at rest or during treadmill walking using [(14)C]-iodoantipyrine. Regional CBF-related tissue radioactivity (CBF-TR) was quantified by autoradiography and analyzed by statistical parametric mapping and region-of- interest analysis. Lesions were confirmed by tyrosine hydroxylase immunohistochemistry and changes in rotational locomotor activity. Functional compensations were bilateral and differed at rest and during treadmill walking. Consistent with the classic view of striatopallidal connections, CBF-TR of lesioned compared to sham-lesioned rats increased in the ipsilateral subthalamic nucleus (STN) and internal globus pallidus, and decreased in the striatum and external globus pallidus. Contrary to the classic view, CBF-TR increased in the ipsilateral ventral lateral, ventral anterior thalamus and motor cortex, as well as in the central medial thalamus, midline cerebellum, and contralateral STN. During walking, perfusion decreased in lesioned compared to sham-lesioned rats across the ipsilateral striato-pallidal-thalamic-cortical motor circuit. Compensatory increases were seen bilaterally in the ventromedial thalamus and red nucleus, in the contralateral STN, anterior substantia nigra, subiculum, motor cortex, and in midline cerebellum. Enhanced recruitment of associative sensory areas was noted cortically and subcortically. Future models of compensatory changes after nigrostriatal damage need to address the effects of increased neural activity by residual dopaminergic neurons, interhemispheric interactions and differences between resting and locomotor states. Identification of sites at which functional compensation occurs may define useful future targets for neurorehabilitative or neurorestorative interventions in Parkinson's disease.

Consolidation of object-discrimination memory is independent of the hippocampus in rats

We examined whether retrograde amnesia would be more likely for object discriminations learned an hour before hippocampal damage than object discriminations learned days before. Specifically, rats were trained on two object-discrimination problems 72 h before surgery and another discrimination problem and the reversal of one of the previously learned problems 1 h before surgery. Importantly, novel procedures that minimized overtraining on the object discriminations were used to increase the possibility of the lesions causing amnesia. After either receiving sham or neurotoxic-induced hippocampal damage, rats were tested for retention using an extinction procedure. Control rats and rats with extensive hippocampal damage displayed a strong bias for the rewarded object on each object-discrimination problem and a significant bias for the most recent contingency learned on the reversal problem. These results suggest that, despite the use of very sensitive training and testing procedures, hippocampal damage did not cause retrograde amnesia. The findings imply that the hippocampus is not critical for the consolidation, storage, or retrieval of object-reward associations, or any other information required for accurate performance of an object discrimination.

Protective effects of S+ ketamine and atropine against lethality and brain damage during soman-induced status epilepticus in guinea-pigs

Soman poisoning is known to induce full-blown tonic-clonic seizures, status epilepticus (SE), seizure-related brain damage (SRBD) and lethality. Previous studies in guinea-pigs have shown that racemic ketamine (KET), with atropine sulfate (AS), is very effective in preventing death, stopping seizures and protecting sensitive brain areas when given up to 1h after a supra-lethal challenge of soman. The active ketamine isomer, S(+) ketamine (S-KET), is more potent than the racemic mixture and it also induces less side-effects. To confirm the efficacy of KET and to evaluate the potential of S-KET for delayed medical treatment of soman-induced SE, we studied different S-KET dose regimens using the same paradigm used with KET. Guinea-pigs received pyridostigmine (26 microg/kg, IM) 30min before soman (62 microg/kg, 2 LD(50), IM), followed by therapy consisting of atropine methyl nitrate (AMN) (4 mg/kg, IM) 1min following soman exposure. S-KET, with AS (10mg/kg), was then administered IM at different times after the onset of seizures, starting at 1h post-soman exposure. The protective efficacy of S-KET proved to be comparable to KET against lethality and SRBD, but at doses two to three times lower. As with KET, delaying treatment by 2h post-poisoning greatly reduced efficacy. Conditions that may have led to an increased S-KET brain concentration (increased doses or number of injections, adjunct treatment with the oxime HI-6) did not prove to be beneficial. In summary, these observations confirm that ketamine, either racemic or S-KET, in association with AS and possibly other drugs, could be highly effective in the delayed treatment of severe soman intoxication.

Brain injury markers (S100B and NSE) in chronic cocaine dependents

OBJECTIVE: Studies have shown signs of brain damage caused by different mechanisms in cocaine users. The serum neuron specific enolase and S100B protein are considered specific biochemical markers of neuronal and glial cell injury. This study aimed at comparing blood levels of S100B and NSE in chronic cocaine users and in volunteers who did not use cocaine or other illicit drugs. METHOD: Twenty subjects dependent on cocaine but not on alcohol or marijuana, and 20 non-substance using controls were recruited. Subjects were selected by consecutive and non-probabilistic sampling. Neuron specific enolase and S100B levels were determined by luminescence assay. RESULTS: Cocaine users had significantly higher scores than controls in all psychiatric dimensions of the SCL-90 and had cognitive deficits in the subtest cubes of WAIS and the word span. Mean serum S100B level was 0.09 ± 0.04 µg/l among cocaine users and 0.08 ± 0.04 µg/l among controls. Mean serum neuron specific enolase level was 9.7 ± 3.5 ng/l among cocaine users and 8.3 ± 2.6 ng/l among controls. CONCLUSIONS: In this first study using these specific brain damage markers in cocaine users, serum levels of S100B and neuron specific enolase were not statistically different between cocaine dependent subjects and controls.

Memory Performance Profile in Occupational Chronic Solvent Encephalopathy Suggests Working Memory Dysfunction

This pilot study characterizes memory functioning of 11 men with occupational chronic solvent encephalopathy (CSE). Pattern (PRM) and spatial recognition (SRM), spatial span (SSP), spatial working memory (SWM), and paired associate learning (PAL) from Cambridge Neuropsychological Test Automated Battery were performed twice. The most sensitive variables to show impairment were PAL trials, SRM total correct, and SWM number of between-search errors. The majority of the CSE patients demonstrated mild deficits. The most persistent dysfunction was in tasks demanding working memory processing, which predicted well the CSE status. Qualitatively, the memory deficits resemble those seen in moderate or severe Parkinson's disease.

Gestational methylazoxymethanol acetate treatment impairs select cognitive functions: parallels to schizophrenia

Gestational methylazoxymethanol acetate (MAM) exposure has been suggested to produce neural and behavioral abnormalities similar to those seen in schizophrenia. In order to assess MAM treatment as a model of schizophrenia, pregnant female rats were injected with MAM (22 mg/kg) on gestational day 17 and their offspring were assessed in adulthood on a series of cognitive tasks. The first experiment involved an attentional set-shifting task, a rodent analog of the Wisconsin card sort task. In experiment 2, animals were tested on the 5-choice serial reaction time task, a rodent analog of the continuous performance task. In the final experiment animals were assessed on a differential reinforcement of low rate of responding 20 s schedule of reinforcement (DRL-20), a task that is sensitive to changes in inhibitory control. In the first experiment, MAM-treated animals required a greater number of trials than controls to successfully learn an extradimensional shift on the set-shifting task, and had difficulties in learning to reverse a previously acquired discrimination. In contrast, MAM-treated animals showed little impairment on the 5-choice task, aside from a modest but consistent increase in premature responding. Finally, MAM exposed animals showed substantial impairments in DRL performance. Post-mortem analysis of brain tissue showed significant decreases in tissue weight in the hippocampus, parietal cortex, prefrontal cortex, and dorsal striatum of MAM-treated animals. These results support the notion that MAM treatment may simulate some aspects of schizophrenic cognition.

Brain morphometry and cognitive performance in detoxified alcohol-dependents with preserved psychosocial functioning

The extent of structural brain damage and related cognitive deficits has been little described in alcohol-dependent individuals with preserved social functioning. Thus, we investigated the relationship between regional alterations, executive performance, and drinking history. Volumes of gray and white matter were assessed using magnetic resonance imaging voxel-based morphometry in healthy men and in detoxified alcohol-dependent men with good psychosocial functioning. Their executive performance was assessed using neuropsychological tests. Regression analyses were carried out in the regions in which volume differences were detected. Decreases in gray matter were detected bilaterally in alcohol-dependents in the dorsolateral frontal cortex (up to 20% lower), and to a lesser extent in the temporal cortex, insula, thalamus, and cerebellum. Decreases in white matter volume were widespread, being up to 10% in corpus callosum. The degradation of neuropsychological performance correlated with gray matter volume decreases in the frontal lobe, insula, hippocampus, thalami and cerebellum, and with white matter decrease in the brainstem. An early age at first drinking was associated with decreased gray matter volumes in the cerebellum, brainstem (pons), and frontal regions. Regional alteration in gray and white matter volume was associated with impairment of executive function despite preserved social and somatic functioning in detoxified patients. Besides involving frontal regions, these findings are consistent with a cerebello-thalamo-cortical model of impaired executive functions in alcohol-dependent individuals.

Trends in anesthesia-related death and brain damage: A closed claims analysis

BACKGROUND

The authors used the American Society of Anesthesiologists Closed Claims Project database to determine changes in the proportion of claims for death or permanent brain damage over a 26-yr period and to identify factors associated with the observed changes.

METHODS

The Closed Claims Project is a structured evaluation of adverse outcomes from 6,894 closed anesthesia malpractice claims. Trends in the proportion of claims for death or permanent brain damage between 1975 and 2000 were analyzed.

RESULTS

Claims for death or brain damage decreased between 1975 and 2000 (odds ratio, 0.95 per year; 95% confidence interval, 0.94-0.96; P < 0.01). The overall downward trend did not seem to be affected by the use of pulse oximetry and end-tidal carbon dioxide monitoring, which began in 1986. The use of these monitors increased from 6% in 1985 to 70% in 1989, and thereafter varied from 63% to 83% through the year 2000. During 1986-2000, respiratory damaging events decreased while cardiovascular damaging events increased, so that by 1992, respiratory and cardiovascular damaging events occurred in approximately the same proportion (28%), a trend that continued through 2000.

CONCLUSION

The significant decrease in the proportion of claims for death or permanent brain damage from 1975 through 2000 seems to be unrelated to a marked increase in the proportion of claims where pulse oximetry and end-tidal carbon dioxide monitoring were used. After the introduction and use of these monitors, there was a significant reduction in the proportion of respiratory and an increase in the proportion of cardiovascular damaging events responsible for death or permanent brain damage.

BHT blocks NF-kappaB activation and ethanol-induced brain damage

BACKGROUND

Binge ethanol administration causes corticolimbic brain damage that models alcoholic neurodegeneration. The mechanism of binge ethanol-induced degeneration is unknown, but is not simple glutamate-N-methyl-D-aspartate (NMDA) excitotoxicity. To test the hypothesis that oxidative stress and inflammation are mechanisms of binge ethanol-induced brain damage, we administered 4 antioxidants, e.g., butylated hydroxytoluene (BHT), ebselen (Eb), vitamin E (VE), and blueberry (BB) extract, during binge ethanol treatment and assessed various measures of neurodegeneration.

METHODS

Adult Sprague-Dawley rats were treated with intragastric ethanol 3 times per day (8-12 g/kg/d) alone or in combination with antioxidants or isocaloric diet for 4 days. Animals were killed, and brains were perfused and extracted for histochemical silver stain determination of brain damage, markers of neurogenesis, or other immunohistochemistry. Some animals were used for determination of nuclear factor kappa B (NF-kappaB)-DNA binding by electrophoretic mobility shift assay (EMSA) or for reverse transcription-polymerase chain reaction (RT-PCR) of cyclooxygenase 2 (COX2).

RESULTS

Binge ethanol induced corticolimbic brain damage and reduced neurogenesis. Treatment with BHT reversed binge induced brain damage and blocked ethanol inhibition of neurogenesis in all regions studied. Interestingly, the other antioxidants studied, e.g., Eb, VE, and BB, did not protect against binge-induced brain damage. Binge ethanol treatment also caused microglia activation, increased NF-kappaB-DNA binding and COX2 expression. Butylated hydroxytoluene reduced binge-induced NF-kappaB-DNA binding and COX2 expression.

CONCLUSIONS

Binge-induced brain damage and activation of NF-kappaB-DNA binding are blocked by BHT. These studies support a neuroinflammatory mechanism of binge ethanol-induced brain damage.

The effects of stereotype threat on cognitive function in ecstasy users

Stereotype threat occurs when individuals, believed to be intellectually inferior, perform badly on cognitive tests they perceive to confirm stereotypes about them. Due to the wide media coverage of studies purporting to show cognitive deficits in ecstasy users it is possible that they experience stereotype threat. This study tested ecstasy and non-ecstasy using polysubstance misusers on a variety of cognitive tests after they had been exposed to stereotype threat. This priming consisted of exposing them to information about the long-term effects of ecstasy which either stated that ecstasy caused memory loss or that it did not. Ecstasy users that had been primed that ecstasy did not cause cognitive deficits performed better than the other three groups on the delayed portion of the prose recall task from the Rivermead Behavioural Memory Test battery. There were no other statistically significant differences between any of the groups on any of the other cognitive tests used. This suggests that stereotype threat exists in ecstasy users and may be influencing their performance in experiments designed to identify cognitive deficits. In order to prevent this occurring in future studies, experimenters must be careful how they conduct their experiments and discuss their results with the media.

Profile of executive and memory function associated with amphetamine and opiate dependence

Cognitive function was assessed in chronic drug users on neurocognitive measures of executive and memory function. Current amphetamine users were contrasted with current opiate users, and these two groups were compared with former users of these substances (abstinent for at least one year). Four groups of participants were recruited: amphetamine-dependent individuals, opiate-dependent individuals, former users of amphetamines, and/or opiates and healthy non-drug taking controls. Participants were administered the Tower of London (TOL) planning task and the 3D-IDED attentional set-shifting task to assess executive function, and Paired Associates Learning and Delayed Pattern Recognition Memory tasks to assess visual memory function. The three groups of substance users showed significant impairments on TOL planning, Pattern Recognition Memory and Paired Associates Learning. Current amphetamine users displayed a greater degree of impairment than current opiate users. Consistent with previous research showing that healthy men are performing better on visuo-spatial tests than women, our male controls remembered significantly more paired associates than their female counterparts. This relationship was reversed in drug users. While performance of female drug users was normal, male drug users showed significant impairment compared to both their female counterparts and male controls. There was no difference in performance between current and former drug users. Neither years of drug abuse nor years of drug abstinence were associated with performance. Chronic drug users display pronounced neuropsychological impairment in the domains of executive and memory function. Impairment persists after several years of drug abstinence and may reflect neuropathology in frontal and temporal cortices.

Regeneration of granule neurons after lesioning of hippocampal dentate gyrus: evaluation using adult mice treated with trimethyltin chloride as a model

The hippocampal dentate gyrus in adult animals is known to contain neural progenitors that proliferate and differentiate into neurons in response to brain injury. Little has been observed, however, on regeneration of the granule cell layer of the dentate gyrus that has been directly injured. Using trimethyltin (TMT)-treated mice as an in vivo model, we evaluated the ability of this layer to regenerate after injury. The administration of TMT induced neuronal death in the dentate gyrus selectively 2 days later, with recovery of granule neurons on day 14 and thereafter. At an early stage (days 2-5) after the damage by TMT treatment, 5-bromo-2'-deoxyuridine (BrdU) incorporation into at least two different types of cells was facilitated in the dentate gyrus: BrdU-positive/neuronal nuclear antigen (NeuN)-negative cells were found predominantly in the subgranular zone and granule cell layer, whereas BrdU-positive/NeuN-positive cells were numerous in the dentate molecular layer and hilus. In addition, expression of proliferating cell nuclear antigen, nestin, NeuroD3, and doublecortin, which are markers for proliferating cells and neural progenitors/neuronal precursors, was extremely enhanced in the dentate gyrus at the early stage after treatment. Double staining revealed that BrdU was colocalized with nestin and doublecortin in the subgranular zone. Behavioral analysis revealed that TMT-induced cognition impairment was ameliorated by day 14 after the treatment. Taken together, our data indicate that the hippocampal dentate gyrus itself is capable of regenerating the neuronal cell layer through rapid enhancement of neurogenesis after injury.

Transient lesion in the splenium of the corpus callosum and antiepileptic drug withdrawal

OBJECTIVE

To test pathophysiologic hypotheses regarding the occurrence of a splenial lesion in patients with epilepsy.

METHODS

The authors studied 16 patients with a splenial lesion and 32 control patients, all of whom had MRI examination immediately after presurgical EEG long-term monitoring (LTM). The authors compared the number of generalized tonic-clonic and partial seizures during LTM, antiepileptic drug (AED) withdrawal, and laboratory results.

RESULTS

All of the patients with a splenial lesion had their AEDs stopped completely, vs 47% of the controls (p = 0.001). Patients with SCC lesion had a longer duration of complete withdrawal (median 3.5 vs 2 days, p = 0.03). There was no correlation with seizure frequency or the introduction of new AEDs.

CONCLUSION

A lesion of the splenium of the corpus callosum in patients with epilepsy is not associated with toxic drug effects or high seizure frequency, but might be induced by a rapid and relatively long-lasting reduction of antiepileptic drugs. Its frequency might be underestimated as MRI after long-term monitoring is rarely done.

Clinical correlates of quantitative EEG alterations in alcoholic patients

OBJECTIVE

To evaluate the incidence and clinical correlations of abnormal QEEG features in alcoholic patients.

METHODS

Quantitative EEG (frequency analysis, absolute and relative powers of the four classical bands) was assessed in 191 male alcoholic patients admitted in our facility for detoxification process. All underwent psychiatric, medical and neurological examination prior to the EEG recording, in search for specific clinical or paraclinical findings. The presence or absence of relevant clinical features was codified as nominal dichotomic variables to be related to specific QEEG features.

RESULTS

Only 7 patients had normal QEEG. The most frequent alteration (81 cases) was decreased power in slow (delta and theta) bands with a concurrent increase in beta band, followed by decreased power only in slow bands (33), increase only in beta band (29), decrease in both slow and alpha bands without beta alterations (28), decrease only in alpha band (6) and others. Alterations in slow and beta bands were uncorrelated. However, a significant correlation was found between decreased power in slow bands and cortical atrophy as revealed by MRI (especially in patients with early onset of alcoholism), time elapsed from the beginning of alcoholic habits (but only in younger or early onset subjects) and in a lesser degree arterial hypertension, but neither with age nor any other clinical or psychiatric feature. On the other hand, increased power in beta band correlated mainly with the use of benzodiazepines, sensoperceptual alterations (hallucinations, illusions), clinical seizures and family history of alcoholism. The effects of those variables were strongly interrelated.

CONCLUSIONS

Decreased power in slow bands in alcoholic patients may be an indicator of brain atrophy or chronic brain damage, while increase in beta band is related to medication use, family history of alcoholism, hallucinations and seizures, suggesting a state of cortical hyperexcitability.

SIGNIFICANCE

This study show the relation of specific QEEG alterations to certain clinical features found in alcoholics, in a further attempt to elucidate the semiological value of those alterations in individual patients.

Cigarette smoking induces heat shock protein 70 kDa expression and apoptosis in rat brain: Modulation by bacoside A

Cigarette smoking is associated with the development of several diseases and antioxidants play a major role in the prevention of smoking-related diseases. Apoptosis is suggested as a possible contributing factor in the pathogenesis of smoking-induced toxicity. Therefore the present study was designed to investigate the influence of chronic cigarette smoke exposure on apoptosis and the modulatory effect of bacoside A (triterpenoid saponin isolated from the plant Bacopa monniera) on smoking-induced apoptosis in rat brain. Adult male albino rats of Wistar strain were exposed to cigarette smoke and simultaneously administered with bacoside A (10 mg/kg b.w./day, orally) for a period of 12 weeks. Expression of brain hsp70 was analyzed by Western blotting. Apoptosis was identified by DNA fragmentation, terminal deoxynucleotidyl transferase-mediated deoxy uridine triphosphate nick end labeling (TUNEL) staining and transmission electron microscopy. The results showed that exposure to cigarette smoke induced hsp70 expression and apoptosis as characterized by DNA laddering, increased TUNEL-positive cells and ultrastructural apoptotic features in the brain. Administration of bacoside A prevented expression of hsp70 and neuronal apoptosis during cigarette smoking. We speculate that apoptosis may be responsible for the smoking-induced brain damage and bacoside A can protect the brain from the toxic effects of cigarette smoking.

Combining exercise and cyclooxygenase-2 inhibition does not ameliorate learning deficits after brain insult, despite an increase in BDNF levels

Neurodegeneration can produce behavioral impairments. Previously, we have found that inhibition of cyclooxygenase-2 activity or physical activity was neuroprotective during kainic-acid-induced neural loss. Here, we investigated the combined effect of exercise pre-insult and cyclooxygenase inhibitor treatment post-kainate-induced brain damage. However, in spite of an increase in BDNF levels, the combination did not improve behavioral performance in Morris watermaze and object exploration tasks.

Brainstem auditory evoked potentials (BAEPs) study in chronic arsenic poisoning patients

OBJECTIVES

To explore the possible neurotoxicity of arsenic to auditory sensory pathways and evaluate roles of BAEPs in the detection of early brain damage resulting from arsenic exposure.

DESIGN

Cross-sectional analytic study.

MATERIAL AND METHOD

Twenty nine females with skin lesions consistent with arsenical dermatoses and 27 controls who met the inclusion criteria were investigatetd by Auditory Evoked Potentials (AEPs). Case findings resulted from a house-to-house survey in village 12, Ronphibun subdistrict and village 5, Saothong subdistrict, Nakhon Si Thammarat Province, southern Thailand in 1995.

RESULTS

Differences between the arsenic-exposed population and the referent group regarding BAEP parameters, BAEP latencies and interpeak latencies were not found.

CONCLUSION

Evidence of the abnormalities of the auditory sensory pathways was not found among female patients with arsenical dermtoses in Ronphibun. The role of BAEPs in the detection of brain damage resulting from arsenic exposure could not be demonstrated.