[Chronic neurotoxic damage in ecstasy (MDMA) users. Review of the current state of research]

The popular dance drug ecstasy (3,4-methylenedioxymethamphetamine, or MDMA, and some analogues) causes selective and persistent neurotoxic damage of the central serotonergic system in laboratory animals. Serotonin plays a role in numerous functional systems in the CNS. Consequently, various abnormalities including psychiatric, vegetative, neuroendocrine, and cognitive disorders might be expected in humans following damage of the central serotonergic system. In recent years, the questions of possible functional disorders following ecstasy-induced neurotoxicity were addressed in several cross-sectional studies with drug users. In this review we summarize and evaluate the quality of design of these studies. Despite large methodological problems, evidence accumulates in favor of persisting brain damage in ecstasy users resulting in subtle cognitive deterioration. Findings of relatively low memory performance associated with heavy ecstasy use are highly consistent across different studies and user populations. In addition, low performance in tests of higher executive function were reported in some but not all studies. The important questions about progression, persistence, or reversibility of damage after long periods of abstinence have to be addressed in future studies with longitudinal design.

Elevation of antioxidant potency in mice brain by low-dose X-ray irradiation and its effect on Fe-NTA-induced brain damage

The increase in lipid peroxide levels in mice brain following Fe3+ administration was about 50% of that when 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) was administered. This may be due to excessive oxidation by Fe3+, and was supported by the decrease in activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GPX), Na+,K(+)-ATPase activity and membrane fluidity after Fe3+ administration. Relatively low-dose X-ray irradiation (0.5 Gy) inhibited lipid peroxidation associated with Fe3+ administration and restored the decreased activities of the above antioxidant enzymes and Na+,K(+)-ATPase, and membrane fluidity to the levels in the non-Fe(3+)-administered group. In the purine metabolism system, uric acid decreased after Fe3+ administration, which may be due to transient impairment of the system for production of uric acid from xanthine by excessive oxidation by Fe3+. However, 0.5 Gy irradiation inhibited this decrease in uric acid, increasing its level to that in the non Fe(3+)-administrated group. This may be due to factors such as rapid recovery of the activities of the above antioxidant enzymes and Na+,K(+)-ATPase, and membrane fluidity after 0.5 Gy irradiation. In addition, since no changes were observed in xanthine and uric acid, increased inosine and hypoxanthine may have advanced to a salvage pathway leading to not xanthine but inosine 5'-monophosphate (IMP).

Routine diagnostic procedures for chronic encephalopathy induced by solvents: survey of experts

OBJECTIVES

To study the routine diagnostic procedures used in different countries for chronic toxic encephalopathy (CTE) induced by solvents.

METHODS

By means of a postal questionnaire selected international experts were asked about the methods they use to diagnose patients suspected of having CTE induced by solvents, the number of patients, entrance criteria, and the results of these diagnostic procedures.

RESULTS

18 Experts working in 18 diagnostic centres responded. Most of them agreed that a diagnostic procedure for CTE induced by solvents should contain an interview and neurological, physical, and neuropsychological examinations. However, the tests used were very different, as were the classifications for CTE. Depending on the institute, a diagnosis of CTE was made in 6%--70% of the referred patients. The proportion of patients with CTE stage I ranged from 0% to 33%, stage II from 5% to 100%, and stage III from 0% to 95%.

CONCLUSION

The intentions of the two 1985 conferences that aimed at clarity and uniformity of diagnosis of CTE induced by solvents are far from reached. It is possible, now the conditions are more favourable, to aim at this important goal and recommend some refinement of the then proposed criteria.

Repeated prenatal corticosteroid administration delays myelination of the corpus callosum in fetal sheep

Glucocorticoids regulate oligodendrocyte maturation and the myelin biosynthetic pathways. Synthetic glucocorticoids, the corticosteroids have been successfully used in clinical practice as a single course to enhance lung maturation and reduce mortality and morbidity in preterm infants with no long-term neurologic or cognitive side effects. However, a trend has arisen to use repeated courses despite an absence of safety data from clinical trials. We examined the effects of clinically appropriate, maternally administrated, repeated courses of corticosteroids on myelination of the corpus callosum using sheep as a large animal model. The corpus callosum is a major white matter tract that undergoes protracted myelination, underpins higher order cognitive processing and developmental damage to which is associated with, for example, cerebral palsy, mental retardation and attention deficit hyperactivity disorder. Pregnant ewes were given saline or betamethasone (0.5 mg/kg) at 104,111,118 and 124 days gestation, stages equivalent to the third trimester in humans. Lambs were delivered at 145 days (term), perfused and the corpus callosum examined light and electron microscopically. Total axon numbers were unaffected (P>0.05). However, myelination was significantly delayed. Myelinated axons were 5.7% in the experimental group and 9.2% in controls (P<0.05); conversely, unmyelinated axons were 88.3 and 83.7% (P<0.05). Myelinated axon diameter and myelin sheath thickness were also reduced (0.68 vs. 0.94 and 0.11 vs. 0.14 microm, P<0.05). Our data suggest that repeated prenatal corticosteroid administration delays myelination of the corpus callosum and that further safety data are needed to evaluate clinical practice.

Effects of nicotine on ethanol dependence and brain damage

Almost all alcoholics (80%-95%) smoke tobacco. When alcoholics binge, they achieve high, sustained blood alcohol levels, become physically dependent, and often suffer loss of cognition and other higher cortical functions. Nicotine could have a modulatory effect on ethanol drinking behavior and ethanol-induced brain damage through its cholinergic actions. To determine whether nicotine altered alcohol dependence, alcohol-induced brain damage, or both, a rat model of binge drinking was used to study the effects of nicotine on the alcohol withdrawal syndrome and its associated brain damage. After administration of the last dose of ethanol in a 4-day binge model, rats remained intoxicated for approximately 5 h, slowly returned to a neutral state, and entered a hyperexcited period, which peaked around 24 h and lasted a total of 60 h. Behavioral signs of withdrawal included splayed limbs, tremors, and seizures. Continuous transdermal nicotine did not alter the duration or severity of ethanol withdrawal. The 4-day binge ethanol treatment caused considerable brain damage in the perirhinal cortex, entorhinal cortex, ventral dentate gyrus, and olfactory bulb as visualized with amino cupric silver stain. Nicotine alone caused little or no brain damage and did not markedly alter binge ethanol-induced damage in cortical or hippocampal regions. In the olfactory bulb, nicotine reduced ethanol-induced brain damage. Although results of other studies seem to indicate that nicotine increases alcohol consumption, our findings indicate that nicotine does not markedly change the development of alcohol dependence or alcohol-induced cortical damage.

Sex difference in alcohol-related organ injury

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Nobuhiro Sato and Kai O. Lindros. The presentations were (1) Sex differences in ethanol pharmacokinetics, by E. Baraona; (2) Estrogen regulates the sensitivity to endotoxin in hepatic Kupffer cells, by K. Ikejima; (3) Sex difference in alcohol-related organ injury, by E. Mezey; (4) Aggravated ethanol-induced liver injury in female rats: Protection by the antiestrogen toremifene, by Harri A. Järveläinen; and (5) Alcohol metabolism in Asian subjects: Sex differences and flushing response, by V. A. Ramchandani.

Permanent brain damage following acute clonidine poisoning in Munchausen by proxy

A child presented with recurrent episodes of lethargia for which he underwent several hospital admissions and investigations. A further episode culminated in respiratory arrest and hypoxic ischemic encephalopathy with permanent mental regression. Eighteen months later the mother was discovered while providing clonidine pills to the child; the mother appears to feature a Munchausen syndrome by proxy.

Function testing for chemical brain damage: a review

Testing of neurobehavioral functions for evaluation of the effects of chemicals on the human brain from community (i.e., environmental) exposures is logical and may be a preferred initial step. Sensitivity is improved (1) by adjusting individual tests for influential factors, found by regression modeling and by retaining significant coefficients; and (2) by the calculation of predicted values for each test for each subject. This two-part approach allows for adjustments in age, sex, educational level, and other factors before comparisons are made. Visual fields, color discrimination, reaction time, balance, and digit symbol are the most sensitive tests, followed by 6 sensitive psychological tests and less-discriminating physiological measurements. Hydrogen sulfide, polychlorinated biphenyls, and arsenic are the most toxic chemicals, followed by chlorine, chlorpyrifos, formaldehyde, nickel carbonyl, and ammonia. The least toxic chemicals, which are hydrochloric acid and chlorine, were determined 7 wk following a community spill. The least toxic chemical among those identified herein is methyl ter butyl ether.

A comparison of neuropsychological tests for the assessment of chronic toxic encephalopathy

BACKGROUND

From the viewpoint of the clinical neuropsychologist, it is not evident if the detection of solvent induced toxic encephalopathy (TE) could be optimized by a modification of the traditional test batteries, adding tests covering new dimensions or monitoring further functional domains.

METHODS

To clarify this issue, TE patients were re-examined with (a) the tests traditionally used in screening for TE and (b) some tests hitherto less utilized within neurotoxicology, involving complex attention and frontal lobe functioning.

RESULTS

The results do not indicate that tests of the latter category would be more sensitive to TE than the tests traditionally used. Using an optimized core battery, compiled of tests from both categories, the sensitivity and specificity levels reached a maximum of around 0.7 when using as criterion the reproduction of a subnormal test profile (TE type 2B).

CONCLUSIONS

A combination of several traditional and a few newer tests is suggested to optimize the detection of TE. Repeated assessments over time are also recommended.

No, some types of nonconvulsive status epilepticus cause little permanent neurologic sequelae (or: "the cure may be worse than the disease")

Nonconvulsive status epilepticus (NCSE) is characterized by a cognitive or behavioral change which lasts for at least 30 minutes, with EEG evidence of seizures. Although there is little argument that generalized nonconvulsive status epilepticus (GNSE) does not cause lasting deficits, there is still debate regarding the morbidity of complex partial status epilepticus (CPSE). Because the EEG is used for diagnosis, a strong argument can be made that NCSE is significantly under-recognized and diagnosed. Furthermore, since the documented cases of permanent neurologic sequelae are few, the potential permanent morbidity from CPSE may be significantly exaggerated. The literature indicates that comatose patients have a poor prognosis largely as a result of comorbid conditions and coma, whereas lightly obtunded or slightly confused patients with NCSE have little or no sequelae. Patients with NCSE may suffer (hypotension and respiratory suppression) from iatrogenic 'aggressive' treatment with intravenous anti-epileptic drugs (IV-AEDs), and the findings in the literature indicate that subjects treated with benzodiazepines may have a worse prognosis. The clinician must balance the potential but rare neurologic morbidity associated with NCSE against the not infrequent morbidity caused by IV-AEDs. Better stratification of the level of consciousness and comorbid conditions is needed when evaluating outcomes so as to clearly distinguish among the deficits due to: comorbid conditions; the effects of treatment and the effects of status epilepticus (SE) proper.

A case of atypical absence seizures induced by leuprolide acetate

We report a case of a 13-year-old female with atypical absence seizures induced by prolonged administration of long-acting leuprolide acetate (LA). This patient had brain involvement resulting from chemotherapy and radiotherapy for a medulloblastoma. At 13 years of age, administration of long-acting LA was started. After the third dose of long-acting LA, atypical absence seizures appeared. After discontinuing long-acting LA, the seizures stopped without administration of any antiepileptic drugs. However, 2 years, 6 months later, the same seizures again appeared. On the basis of the findings of endocrinologic investigations and the reported data of pharmacokinetics of LA, we speculate that her seizures were induced by LA and that the seizures were associated with the presence of brain damage in the patient. Care should therefore be taken when using long-acting LA or other gonadotropin-releasing hormone analogues for pediatric patients with diffuse brain damage.

Protective effect of microglial conditioning medium on neuronal damage induced by glutamate

To examine the effect of microglial conditioning medium (MCM) on damaged neurons, cultured neurons exposed to glutamate were incubated with MCM. More neurons survived in these groups, particularly in the case of glutamate stimulation of microglia. Therefore cultured neurons exposed to glutamate were incubated with MCM at predetermined intervals after glutamate stimulation. Neuronal cultures using MCM at 1, 2 and 6 h after glutamate stimulation had more surviving cells than those using unstimulated MCM. Neuronal cultures using MCM at 12 and 24 h had as much surviving cells as those using unstimulated MCM. These results indicate that the neuroprotective effect of microglia appears only in the early phase after treatment of glutamate and disappears in the late phase.

Stress management in men with solvent-induced chronic toxic encephalopathy

Stress management was studied in male patients with solvent-induced chronic toxic encephalopathy (TE) of types 2A (TE 2A, n = 31) and 2B (TE 2B, n = 26). The patients were compared with a healthy reference group (n = 57). Self-reported symptoms (90-item Symptoms Checklist [SCL-90]), sense of coherence, coping strategies, and level of mastery were measured. As expected, both TE groups reported highly deviating symptoms on most SCL-90 scales. The TE 2B patients, who had objectified cognitive dysfunction, reported more use of passive, less situationally adequate coping strategies; a weaker sense of coherence; and a lower degree of mastery. In contrast, the TE 2A cases showed only minor deviations from the reference group in these respects. The results suggest that having a strong sense of coherence, a sense of mastery, and flexible resources for stress management could be dependent on intact brain functions.

Cocaine-associated stroke: three cases and rehabilitation considerations

Cocaine-associated stroke (CAS) is an important cause of disability, especially among younger adults. Improved management has increased survival but little has been discussed about rehabilitation, including medication management. Therefore, experience and therapeutic drug management are described during inpatient rehabilitation with three patients with CAS. Case 14 is a 50-year-old male with a history of hypertension who presented with right hemiparesis, aphasia and depression. He was treated with paroxetine for depression and bromocriptine for poor initiation with a good response, improving by 50 FIM points in 44 days. Case 2 is a 44 year-old female with quadriparesis, aphasia, and deficits in attention and initiation. Methylphenidate for attention deficits and bromocriptine for poor initiation was associated with an excellent functional gain (50 FIM points in 37 days). She eventually returned to work. Case 3 is a 46-year-old female with a history of hypertension who presented with right hemiparesis, aphasia and depression. Without neuropharmacologic intervention, she gained 35 FIM points during an uneventful 47 day rehabilitation stay. Acutely, cocaine can induce cerebral vasoconstriction, cerebrovascular spasm, cerebral vasculitis and intracerebral haemorrhage. Chronic use depletes and destroys dopaminergic pathways, which may be a major factor in depression, and attention and initiation deficits-all observed in these cases. Generally, rapid improvements were seen in mood and cognition in two cases where medication was used. Based on the current literature and pathophysiology of CAS, it is suggested that trials of dopaminergic agents for cognition and extremely cautious use of buproprion for depression may be warrented. Details of the above cases and the practical and theoretical issues of neuropharmacologic intervention in CAS are discussed.

The incidence of T2-weighted MR imaging signal abnormalities in the brain of cocaine-dependent patients is age-related and region-specific

BACKGROUND AND PURPOSE

Cocaine and its metabolites can produce vasospasm, and cocaine-dependent patients are at increased risk for stroke. Based on previous case reports, we hypothesized that the incidence of hyperintense brain lesions observed on T2-weighted MR images would also be increased in asymptomatic cocaine-dependent individuals.

METHODS

Sixty-two male "crack" (smoked) cocaine-dependent participants ranging in age from 25 to 66 years were compared with 116 normal male control participants ranging in age from 25 to 80 years. Those with histories of neurologic symptoms or illnesses were excluded. The severity of hyperintense lesions was rated on a 0- to 3-point scale, and ratings of 3 were used in the data analysis as an indicator of a probable pathologic process. Three regions were separately rated: the cerebral white matter, insular subcortex white matter, and subcortical gray matter (basal ganglia and thalamus region).

RESULTS

Significantly increased risk of severe lesions was observed in the two white matter regions of the cocaine-dependent group (odds ratio of 16.7 and 20.3) but not in the subcortial gray matter region (odds ratio of 1.4). In the insula subcortex white matter, the risk of lesions increased with age in the cocaine-dependant sample, but remained essentially absent among normal controls through the age of 80 years. In the cerebral white matter, the relationship of age and risk of lesion among normal participants was similar in shape to that in cocaine-dependent participants, but equivalent risk was seen 20 years earlier among cocaine-dependent participants.

CONCLUSIONS

Cocaine-dependent participants had a significantly increased age-related risk of white matter damage. The possible clinical implications of this damage are discussed.

Disturbance of cerebral function in people exposed to drinking water contaminated with aluminium sulphate: retrospective study of the Camelford water incident

OBJECTIVE

To establish whether people exposed to drinking water contaminated with 20 tonnes of aluminium sulphate in the Camelford area of Cornwall in the south west of England in July 1988 had suffered organic brain damage as opposed to psychological trauma only.

DESIGN

Retrospective study of affected people.

PARTICIPANTS

55 affected people and 15 siblings nearest in age to one of the group but who had not been exposed to the contaminated water were studied.

MAIN OUTCOME MEASURES

Various clinical and psychological tests to determine medical condition and anxiety levels in affected people. Assessment of premorbid IQ (pFSIQ) with the national adult reading test, a computerised battery of psychomotor testing, and measurement of the difference in latencies between the flash and pattern visual evoked potentials in all participants.

RESULTS

The mean (SE) pFSIQ was above average at 114.4 (1.1). The most sensitive of the psychomotor tests for organic brain disease was the symbol digit coding (SDC) test (normal score 100, abnormal <85). PARTICIPANTS performed less well on this test (54.5 (6.0)) than expected from their pFSIQ (P<0.0001) and a little less poorly on the averaged less discriminating tests within the battery (86.1 (2.5), P<0.0001). In a comparison with the 15 sibling pairs (affected people's age 41.0 (3.3) years v sibling age of 42.7 (3.1) years (P=0.36) the exposed people had similar pFSIQ (114.7 (2.1)) to their siblings (116.3 (2.1), (P=0.59) but performed badly on the symbol digit coding test (51.8 (16.6)) v (87.5 (4.9) for siblings, P=0.03). The flash-pattern differences in exposed people were greater than in 42 unrelated control subjects of similar age (27.33 (1.64) ms v 18. 57 (1.47) ms, P=0.0002). The 15 unexposed siblings had significantly better flash-pattern differences than their affected siblings (13.4 (2.4) ms v 29.6 (2.9) ms, P=0.0002). No effect of anxiety could be shown on these measurements from the analysis of the anxiety scores of exposed people.

CONCLUSION

People who were exposed to the contaminated water at Camelford suffered considerable damage to cerebral function, which was not related to anxiety. Follow up studies would be required to determine the longer term prognosis for affected individuals.

Brain damage and hypoxia in an ovine fetal chronic cocaine model

OBJECTIVE

To assess the development of brain damage in an ovine fetal chronic cocaine model. To evaluate the effect of isolated hypoxic tests on this model and to correlate hemodynamic findings (brain-sparing effect) following fetal hypoxia and the occurrence of brain damage.

STUDY DESIGN

Fifteen ewes were divided into a control group (n=7) and a cocaine treated group (n=8). From day 65 to day 134 the cocaine treated animals received a daily (5 days per week) intramuscular injection (2 mg/kg cocaine) and the control animals a placebo injection (2 ml of isotonic solution). Both groups underwent hypoxic tests (cord compression (3 min) and aortic compression (1 min)) at 90 and 134 days. In addition, anesthesia for magnetic resonance imaging (MRI) examination was carried out at 125 days. Fetal blood samples were collected during both series of hypoxic tests and the cerebral and umbilical flows were monitored by Doppler. Samples from 25 brains (control n = 10; cocaine n= 15) were processed for light and electron microscopic examination. Quantification of brain damage was done on semithin sections from six areas of cortex and germinal matrix on each fetus.

RESULTS

Similar forms of brain damage (selective neuronal loss limited to the parasaggital cortex, striatum, hippocampus and Purkinje cells) was present in both groups but lesions were more frequent in the cocaine treated group as shown by quantitative analysis for the proportion of abnormal capillaries (65% vs. 35%), capillary edema (61% vs. 34%) and abnormal neurons showing delayed neuronal degeneration (DND) (66% vs. 36%) in the cocaine and control group respectively. There was no significant difference in immunoreactivity for glial fibrillary acidic protein (GFAP) but it was more marked in the cerebellum of cocaine treated animals. Fetal blood samples showed a moderate sustained hypoxia and Doppler findings demonstrated the presence of a brain sparing effect associated with increased uterine and umbilical vascular resistance in the cocaine treated group. Nevertheless, the amplitude of the heart rate increase and cerebral dilatation was significantly lower in the cocaine treated animals.

CONCLUSION

This ovine fetal chronic cocaine model showed the presence of brain damage. Cocaine treatment seems to potentiate the effect of the hypoxic tests. Independent of the cause, the brain damage developed in the presence of brain sparing effect, strongly suggesting that this phenomenon is a sign of a pathological fetal condition and no guarantee that it will prevent tissue damage.

Hyperbaric oxygen therapy in childhood carbon monoxide poisoning

Hyperbaric oxygen therapy is the administration of 100% oxygen at pressures two to three times ambient pressure, and it significantly increases dissolved oxygen content. Although it has been used successfully to treat decompression illness and arterial air embolism, its role in the treatment of carbon monoxide poisoning remains somewhat controversial. Published evidence and guidelines for the use of hyperbaric oxygen therapy in carbon monoxide-poisoned infants and children are scarce compared with those available for carbon monoxide-poisoned adults. Because of their higher metabolic rates and developing nervous systems, infants and children may be more susceptible to the effects of carbon monoxide and also may warrant special considerations. This review focuses on the unique aspects of carbon monoxide poisoning and hyperbaric oxygen therapy in the fetus, the newborn, the infant, and the child. In addition, it discusses general indications for and special and practical considerations in the use of hyperbaric oxygen therapy in children.