Immune response-associated production of neopterin. Release from macrophages primarily under control of interferon-gamma

Neopterin, a compound derived from GTP, represents a precursor molecule of biopterin that is an essential cofactor in neurotransmitter synthesis. We have recently reported that in vivo as well as in vitro immune responses are accompanied by an increased release of neopterin and that this phenomenon can be used for the biochemical monitoring of diseases accompanied by hyperimmune stimulation. This article deals with the cellular origin and the control of this immune response-associated neopterin release in vitro. Using highly purified or monoclonal cellular reagents we demonstrate that macrophages (M phi) stimulated with supernatants from activated T cells release large amounts of neopterin into culture supernatants. Further experiments involving induction of neopterin release from M phi with various human recombinant interferons (IFNs) or neutralization of the effect of T cell supernatants with various monoclonal anti-IFN antibodies revealed immune IFN as the active principle. It thus appears that a metabolic pathway so far exclusively known in context with the generation of an essential cofactor of neurotransmitter-synthesis during immune responses is also activated in M phi under stringent control by immune IFN-like lymphokines.

High-frequency unilateral thalamic stimulation in the treatment of essential and parkinsonian tremor

Pharmacologic treatment for essential tremor and the tremor of Parkinson's disease is often inadequate. Stereotaxic surgery, such as thalamotomy, can effectively reduce tremors. We performed a multicenter trial of unilateral high-frequency stimulation of the ventral intermedius nucleus of the thalamus in 29 patients with essential tremor and 24 patients with Parkinson's disease, using a blinded assessment at 3 months after surgery to compare clinical rating of tremor with stimulation ON with stimulation OFF and baseline and a 1-year follow-up. Six patients were not implanted because of lack of intraoperative tremor suppression (2 patients), hemorrhage (2 patients), withdrawal of consent (1 patient), and persistent microthalamotomy effect (1 patient). A significant reduction in both essential and parkinsonian tremor occurred contralaterally with stimulation. Patients reported a significant reduction in disability. Measures of function were significantly improved in patients with essential tremor. Complications related to surgery in implanted patients were few. Stimulation was commonly associated with transient paresthesias. Other adverse effects were mild and well tolerated. Efficacy was not reduced at 1 year. Chronic high-frequency stimulation is safe and highly effective in ameliorating essential and parkinsonian tremor.

Consensus statement on the diagnosis of multiple system atrophy. American Autonomic Society and American Academy of Neurology

We report the results of a consensus conference on the diagnosis of multiple system atrophy (MSA). We describe the clinical features of the disease, which include four domains: autonomic failure/urinary dysfunction, parkinsonism and cerebellar ataxia, and corticospinal dysfunction. We set criteria to define the relative importance of these features. The diagnosis of possible MSA requires one criterion plus two features from separate domains. The diagnosis of probable MSA requires the criterion for autonomic failure/urinary dysfunction plus poor levodopa responsive parkinsonism or cerebellar ataxia. The diagnosis of definite MSA requires pathological confirmation.

Criterion for determining clustering versus reentrant melting behavior for bounded interaction potentials

We examine in full generality the phase behavior of systems whose constituent particles interact by means of potentials that do not diverge at the origin, are free of attractive parts, and decay fast enough to zero as the interparticle separation r goes to infinity. By employing a mean field-density functional theory which is shown to become exact at high temperatures and/or densities, we establish a criterion that determines whether a given system will freeze at all temperatures or it will display reentrant melting and an upper freezing temperature.

Optical performance of multifocal intraocular lenses

The optical performance of one monofocal and five multifocal lenses was evaluated in the laboratory and photographically. The laboratory testing included determination of the modulation transfer function (MTF), through focus response (TFR), resolution efficiency, and Strehl ratio of each lens. The photographic testing included photographs of the Regan high contrast acuity chart at ten feet with clearest focus and 18 additional photographs in which the image was defocused using minus trial lenses in 0.25 diopter increments. A color photograph of the Kodak color chart was also taken using each lens. All testing was conducted using a 3 mm artificial pupil under ideal implant conditions with no decentration or tilt. The laboratory and photographic results demonstrate that all the multifocal lenses had a two- to three-fold increase in the depth of field with at least a 50% lower contrast in the retinal image. The photographic testing revealed a one to two line better resolution limit with the monofocal lens, which corresponded to the 12% to 41% better MTF cut-off value with the monofocal lens by laboratory testing. The measured resolution efficiencies of all six lenses were comparable. The color photographs revealed color mixing of adjacent colors with the multifocal lenses, whereas the colors appeared unchanged from the original with the monofocal lens.

Striatal dopamine distribution in parkinsonian patients during life

Eleven neuropsychologically normal Parkinsonian patients were studied with [18F]6-fluoro-L-dopa and positron tomography. In all of the patients dopaminergic activity was reduced in the putamen on the side opposite to the major motor signs. The reduction was similar in tremulous and rigid patients. In contrast dopaminergic activity was normal in the caudate nuclei. It is argued that the putamen is mainly involved in the regulation of movement while the caudate nuclei assume a role in cognitive processes.

Stimulation of angiogenesis through cathepsin B inactivation of the tissue inhibitors of matrix metalloproteinases

The tissue inhibitors of matrix metalloproteinases (MMPs), TIMP-1 and TIMP-2, are also angiogenesis inhibitors. Cathepsin B and MMPs are found at sites of neovascularization in pathologies such as cancer and osteoarthritis. Treatment of TIMP-1, TIMP-2, and of a mixture of both inhibitors from human articular chondrocytes with cathepsin B resulted in their fragmentation, whereby they lost their MMP-inhibitory and anti-angiogenic activities. Our data suggest that, besides directly participating in tissue destruction, cathepsin B can be harmful for two further reasons: it raises the activity of the MMPs also in the absence of mechanisms up-regulating these enzymes, and it stimulates angiogenesis. This is a prerequisite for blood vessel invasion in a variety of pathological situations of which cancer and osteoarthritis are prominent examples.

Nuclear factor kappaB in proliferation, activation, and apoptosis in rat hepatic stellate cells

BACKGROUND/AIMS

Activation of the transcription factor NFkappaB has been demonstrated in activated hepatic stellate cells (HSCs). We investigated the role of NFkappaB in proliferation, in activation, and in TNFalpha-induced apoptosis of HSCs.

METHODS

NFkappaB activation was inhibited using an adenovirus expressing an IkappaB dominant negative protein (Ad5IkappaB) in both quiescent and activated HSCs. Quiescent HSCs were infected with Ad5IkappaB or an adenovirus expressing beta-galactosidase (Ad5LacZ). The cells were cultured for 7 days. HSCs activation was determined by cell morphology, smooth muscle alpha-actin (alpha-sma) expression, and steady-state mRNA levels of alpha1(I) collagen as assessed by Western blot and RNase protection assay, respectively. Proliferation was determined in culture-activated HSCs by 3H-thymidine incorporation and direct cell counting. Apoptosis was analyzed by infecting quiescent or activated HSCs with Ad5IkappaB or Ad5LacZ, and then treating with TNFalpha. Apoptosis was demonstrated by determining cell number, assessing nuclear morphology, TUNEL assay and caspase 3 activity.

RESULTS

After 7 days in culture no differences were noted between the Ad5IkappaB- and the Ad5LacZ-infected cells in the morphology, alpha-sma expression or in alpha1(I) collagen mRNA levels. Ad5IkappaB infection did not modify proliferation in activated HSCs. TNFalpha induced apoptosis only in Ad5IkappaB-infected activated, but not quiescent HSCs. Apoptosis was initially demonstrated 12 h after exposure to TNFalpha. Twenty-four h after the TNFalpha treatment, 60% of the activated HSCs were apoptotic.

CONCLUSION

NFkappaB activity is not required for proliferation or activation of HSCs; however, NFkappaB protects activated HSCs against TNFalpha-induced apoptosis.

Botulinum toxin for essential tremor of the voice with multiple anatomical sites of tremor: a crossover design study of unilateral versus bilateral injection

OBJECTIVES/HYPOTHESIS

To evaluate the relative efficacy of unilateral and bilateral injections of botulinum toxin injection (BOTOX) in the treatment of essential tremor of the voice (ETV).

STUDY DESIGN

Prospective open-label crossover study.

METHODS

Patients referred to the Neurolaryngology Clinic at Toronto General Hospital with a diagnosis of ETV were eligible for the study. Patients were sequentially assigned to receive BOTOX as either a bilateral 2.5-U or a unilateral 15-U electromyography-guided injection, followed by the alternative injection 16 to 18 weeks later. Acoustic, aerodynamic, and nasopharyngoscopic data were collected approximately 2, 6, 10, and 16 weeks after each injection. Patients were asked to provide a perceptual evaluation of BOTOX effects at the conclusion of the study.

RESULTS

Three of 10 patients demonstrated an objective reduction in tremor severity with bilateral injection, and 2 of 9 with unilateral injection. However, 8 of 10 patients wished to be re-injected at the conclusion of the study. A reduction in vocal effort appeared to be coincident with reduction in laryngeal airway resistance after BOTOX injection.

CONCLUSIONS

Using objective acoustic measures, only a small proportion of patients achieved benefit from BOTOX injection for ETV. However, a majority of patients in our study benefited from a subjective reduction in vocal effort that may have been attributable to reduced laryngeal airway resistance.

Patient perception of tics and other movement disorders

To determine the subjective perception patients have of abnormal movements, 170 patients with various hyperkinesias were interviewed with questions directed at the "voluntary" or intentional versus "involuntary" aspects of their symptoms. One hundred and two of 110 patients with non-tic disorders thought that the abnormal movements were entirely involuntary. Forty-one of 60 tic disorder patients stated that all their motor and phonic tics were intentionally produced. Fifteen others had both voluntary and involuntary components, usually with the former predominating. A "voluntary" response could be used to predict the correct diagnostic category (tic versus non-tic) in 8 of 9 patients for whom the referral category was incorrect. These results suggest that a large proportion of the motor and phonic symptoms experienced by tic patients are irresistibly but purposefully executed, more akin to compulsions than to the other "involuntary" hyperkinesias with which they are commonly discussed.

Analysis of edge glare phenomena in intraocular lens edge designs

PURPOSE

To determine the image and relative intensity of reflected glare images from 4 commonly used intraocular lens (IOL) edge designs to assess the potential for noticeable postoperative edge glare.

SETTING

University of Texas Medical School, Houston, Texas, USA.

METHODS

The interaction of light rays from 4 common IOL edge designs were examined in an eye model using the OptiCAD 3-D radiometric ray-tracing program (Opticad Corp.). Comparison of the potential of the 4 edge designs to produce visual sensations was derived from plots of the spatial location and energy distribution of rays forming the retinal image.

RESULTS

Edge designs with no anterior and posterior dioptric powers at the lens periphery (lenticular) and rounded corners distributed the edge glare rays over a large retinal area. Edge designs with sharp edges formed by "cropping" the anterior and posterior optic zones focused edge glare rays into distinct arc-shaped images. The peak intensity of the arc-shaped image was 8 to 10 times stronger than the peak intensity of the diffuse image formed by lenses with rounded edges.

CONCLUSIONS

Rounded IOL edges distribute reflected glare image over a significantly greater area than sharp edges. Rounded edges reduce the potential for edge glare phenomena that appear to the patient as a thin crescent or partial ring.

Severe asthma in childhood: assessed in 10 year olds in a birth cohort study

BACKGROUND

Limited information is available regarding the prevalence of severe asthma in children. The present study aimed at investigating the prevalence of severe asthma in an urban child population; secondarily evaluating the applicability of the chosen definition by clinical characteristics.

METHODS

Children enrolled in the prospective birth cohort; the Environment and Childhood Asthma Study in Oslo; were reinvestigated at the age of 10 years (n = 1019). A representative population based cohort of 616 children [mean age 10.9 (SD 0.9) years] with lung function measurements at birth was used for prevalence estimates, whereas all 1019 children (154 with current asthma) attending the 10-year follow-up were included for verification of the definition of severe asthma. Clinical investigations included spirometry, tests of bronchial hyperresponsiveness, skin prick tests and exhaled nitric oxide. Severe asthma was defined as poorly controlled asthma despite treatment with > or = 800 microg budesonide or equivalent; assessed by a detailed structured interview.

RESULTS

The population point prevalence at age 10 years of current severe asthma was 0.5% (three of 616) and among children with current asthma 4.5% (three of 67). The 10/154 children identified as suffering from severe asthma more often had severe bronchial hyperresponsiveness (PD(20) methacholine <1 micromol) (60%vs 22%, P = 0.015), lower median forced expiratory volume in 1 s/forced vital capacity ratio (93%vs 99%, P = 0.04) and higher body mass index (mean BMI 22.3 vs 18.3, P < 0.001) than nonsevere current asthmatics.

CONCLUSIONS

The prevalence of severe asthma was 0.5% in all 10-year olds, and 4.5% among current asthmatics. The severe asthma definition applied in this study is supported by results of clinical investigations.

The 1.8-A crystal structure of a matrix metalloproteinase 8-barbiturate inhibitor complex reveals a previously unobserved mechanism for collagenase substrate recognition

The individual zinc endoproteinases of the tissue degrading matrix metalloproteinase (MMP) family share a common catalytic architecture but are differentiated with respect to substrate specificity, localization, and activation. Variation in domain structure and more subtle structural differences control their characteristic specificity profiles for substrates from among four distinct classes (Nagase, H., and Woessner, J. F. J. (1999) J. Biol. Chem. 274, 21491-21494). Exploitation of these differences may be decisive for the design of anticancer or other drugs, which should be highly selective for their particular MMP targets. Based on the 1.8-A crystal structure of human neutrophil collagenase (MMP-8) in complex with an active site-directed inhibitor (RO200-1770), we identify and describe new structural determinants for substrate and inhibitor recognition in addition to the primary substrate recognition sites. RO200-1770 induces a major rearrangement at a position relevant to substrate recognition near the MMP-8 active site (Ala206-Asn218). In stromelysin (MMP-3), competing stabilizing interactions at the analogous segment hinder a similar rearrangement, consistent with kinetic profiling of several MMPs. Despite the apparent dissimilarity of the inhibitors, the central 2-hydroxypyrimidine-4,6-dione (barbiturate) ring of the inhibitor RO200-1770 mimics the interactions of the hydroxamate-derived inhibitor batimastat (Grams, F., Reinemer, P., Powers, J. C., Kleine, T., Pieper, M., Tschesche, H., Huber, R., and Bode, W. (1995) Eur. J. Biochem. 228, 830-841) for binding to MMP-8. The two additional phenyl and piperidyl ring substituents of the inhibitor bind into the S1' and S2' pockets of MMP-8, respectively. The crystal lattice contains a hydrogen bond between the O(gamma) group of Ser209 and N(delta)1 of His207 of a symmetry related molecule; this interaction suggests a model for recognition of hydroxyprolines present in physiological substrates. We also identify a collagenase-characteristic cis-peptide bond, Asn188-Tyr189, on a loop essential for collagenolytic activity. The sequence conservation pattern at this position marks this cis-peptide bond as a determinant for triple-helical collagen recognition and processing.

Psychogenic tremors

We diagnosed 24 patients, 9 men and 15 women ranging in age from 15 to 78 years, with clinically established or documented psychogenic tremors. Clinical presentations were unique, with complex tremors (often resting, postural, and kinetic), unusual temporal profiles (abrupt onset with a variable course), absence of other neurologic signs, inconsistent and incongruous symptomatology, selective disability with ability to perform some functions despite severe tremors, distractibility that lessens or abolishes tremor, atypical tremorgraphic recordings with changing amplitude and frequency, unusual handwriting and drawing specimens, presence of multiple undiagnosed somatizations, unresponsiveness to all treatments, absence of documented disease by laboratory or radiographic tests, presence of psychiatric disease, spontaneous remissions, or recovery with psychotherapy. We present criteria for the diagnosis of psychogenic tremor.

Promotion and inhibition of flower formation in a dayneutral plant in grafts with a short-day plant and a long-day plant

Flower formation in the dayneutral tobacco (Nicotiana tabacum L.) cultivar "Trapezond" was accelerated by graft union with the short-day tobacco "Maryland Mammoth" when the grafts were kept on short days and by graft union with the long-day plant N. silvestris L. when they were kept on long days. When Maryland Mammoth/Trapezond grafts were kept on long days, flower formation in Trapezond was not, or only slightly, delayed compared to Trapezond/Trapezond controls; but when N. silvestris/Trapezond grafts were kept on short days, flower formation in Trapezond was inhibited and its growth changed to dwarf-like habit. The former results indicate transmission of flower-promoting material(s) ("florigen") from photoperiodic plants maintained under flower-promoting daylength conditions to a dayneutral graft partner; the latter indicate the presence in the long-day plant N. silvestris under short-day conditions of potent flower-inhibiting and growth-regulating material(s) that can also be transmitted to a day-neutral partner. Analogous flower-inhibitory materials seem not to be present, or to be present to a much lesser extent, in the short-day plant Maryland Mammoth under long-day conditions.

Coagulation factor IXa: the relaxed conformation of Tyr99 blocks substrate binding

BACKGROUND

Among the S1 family of serine proteinases, the blood coagulation factor IXa (fIXa) is uniquely inefficient against synthetic peptide substrates. Mutagenesis studies show that a loop of residues at the S2-S4 substrate-binding cleft (the 99-loop) contributes to the low efficiency. The crystal structure of porcine fIXa in complex with the inhibitor D-Phe-Pro-Arg-chloromethylketone (PPACK) was unable to directly clarify the role of the 99-loop, as the doubly covalent inhibitor induced an active conformation of fIXa.

RESULTS

The crystal structure of a recombinant two-domain construct of human fIXa in complex with p-aminobenzamidine shows that the Tyr99 sidechain adopts an atypical conformation in the absence of substrate interactions. In this conformation, the hydroxyl group occupies the volume corresponding to the mainchain of a canonically bound substrate P2 residue. To accommodate substrate binding, Tyr99 must adopt a higher energy conformation that creates the S2 pocket and restricts the S4 pocket, as in fIXa-PPACK. The energy cost may contribute significantly to the poor K(M) values of fIXa for chromogenic substrates. In homologs, such as factor Xa and tissue plasminogen activator, the different conformation of the 99-loop leaves Tyr99 in low-energy conformations in both bound and unbound states.

CONCLUSIONS

Molecular recognition of substrates by fIXa seems to be determined by the action of the 99-loop on Tyr99. This is in contrast to other coagulation enzymes where, in general, the chemical nature of residue 99 determines molecular recognition in S2 and S3-S4. This dominant role on substrate interaction suggests that the 99-loop may be rearranged in the physiological fX activation complex of fIXa, fVIIIa, and fX.

Evidence suggesting under-treatment in adults with idiopathic focal segmental glomerulosclerosis. Regional Glomerulonephritis Registry Study

During the past 11 years, the Metro Toronto Glomerulonephritis Registry has prospectively followed all cases of glomerulonephritis starting from the time of biopsy. Focal segmental glomerulosclerosis was diagnosed by strict histologic criteria in 103 patients. Exclusion of patients with follow-up of less than 12 months reduced the number to 93 (55 adults and 38 children). Mean length of follow-up from the time of biopsy was 61 months. Ninety percent of children, but only 33 percent of adults received treatment with steroids, with or without cytotoxic drugs (p less than 0.001). Complete remission, defined as daily proteinuria of less than 250 mg, was not different in adults (39 percent) from that in children (44 percent), with a mean remission duration for all patients of 38 months. Chronic renal insufficiency, defined as a creatinine clearance of less than 0.8 ml/second/1.73 m2 for more than 12 months, was similar in adults (40 percent) and children (34 percent). Five-year renal actuarial survival, defined as the absence of chronic renal insufficiency, was 96 percent for patients with a history of complete remission, and 55 percent for those without (p less than 0.0002). Logistic regression analysis showed treatment to be the only significant factor for complete remission (p less than 0.001). Complete remission, in turn, was important for renal preservation, defined as the absence of chronic renal insufficiency (p less than 0.001). Age did not affect the treatment response or long-term renal outcome in focal segmental glomerulosclerosis. yet, the percent of adults treated was much lower than that of children, despite the fact that the majority of the untreated adults had the same clinical parameters as the treated adults and children. Thus, a judicious course of treatment is as much indicated in adults as in children with this disorder.

Addition of an immunomodulator can reverse antibody formation and loss of response in patients treated with adalimumab

BACKGROUND

Anti-adalimumab antibodies (AAA) are associated with loss of clinical response (LOR). Addition of an immunomodulator has been shown to reverse immunogenicity and regain response with infliximab monotherapy. Similar data on adalimumab are lacking.

AIM

To study the impact of immunomodulator addition on the emergence of AAA and LOR among adalimumab therapy patients.

METHODS

The databases of three tertiary medical centres were reviewed to identify patients who developed AAA during adalimumab monotherapy with resultant LOR, and received an immunomodulator as a salvage combination therapy. All sera were prospectively analysed using previously described ELISA assays. Clinical response was determined using appropriate clinical scores. Elimination of AAA, designated as 'sero-reversal', elevation of drug levels and regained clinical response were the sought outcomes.

RESULTS

Twenty-three patients (21 Crohn's disease, and 2 ulcerative colitis) developed AAA with subsequent LOR and were thereafter prescribed an immunomodulator as salvage therapy (thiopurine n = 14, methotrexate n = 9). Eleven patients (48%) underwent sero-reversal with gradual elimination of AAA, increase in drug trough levels and restoration of clinical response (median time to sero-reversal 5 months). In 12 patients (52%), immunogenicity and loss of response could not be reversed. There was no difference between responders and nonresponders in the type of immunomodulators used or baseline clinical characteristics.

CONCLUSIONS

In almost half of inflammatory bowel disease patients developing anti-adalimumab antibodies and loss of response, established immunogenicity of adalimumab can be gradually reversed by the addition of immunomodulator therapy with restoration of a clinico-biological response. However, these observations need to be confirmed with larger studies.

Functional correlates of pallidal stimulation for Parkinson's disease

We measured regional cerebral blood flow with H2 15O and positron emission tomography (PET) scanning at rest and during a motor task to study the mechanism of motor improvement induced by deep brain stimulation of the internal globus pallidus in Parkinson's disease. Six right-handed patients with Parkinson's disease were scanned while performing a predictable paced sequence of reaching movements and while observing the same screen displays and tones. PET studies were performed ON and OFF stimulation in a medication-free state. Internal globus pallidus deep brain stimulation improved off-state United Parkinson's Disease Rating Scale motor ratings (37%, p < 0.002) and reduced timing errors (movement onset time, 55%, p < 0.01) as well as spatial errors (10%, p < 0.02). Concurrent regional cerebral blood flow recordings revealed a significant enhancement of motor activation responses in the left sensorimotor cortex (Brodmann area [BA] 4), bilaterally in the supplementary motor area (BA 6), and in the right anterior cingulate cortex (BA 24/32). Significant correlations were evident between the improvement in motor performance and the regional cerebral blood flow changes mediated by stimulation. With internal globus pallidus deep brain stimulation, improved movement initiation correlated with regional cerebral blood flow increases in the left sensorimotor cortex and ventrolateral thalamus and in the contralateral cerebellum. By contrast, improved spatial accuracy correlated with regional cerebral blood flow increases in both cerebellar hemispheres and in the left sensorimotor cortex. These results suggest that internal globus pallidus deep brain stimulation may selectively improve different aspects of motor performance. Multiple, overlapping neural pathways may be modulated by this intervention.

Rats with anxious or non-anxious type of exploratory behaviour differ in their brain CCK-8 and benzodiazepine receptor characteristics

Rats with high and low exploratory activity in an elevated plus-maze model of anxiety were separated into subgroups termed 'non-anxious' and 'anxious' respectively according to the number of sectors the animals crossed and the total amount of time they spent in the open part of the plus-maze. The binding parameters of benzodiazepine and cholecystokinin octapeptide (CCK-8) receptors in frontal cortex and hippocampus of selected animals were studied and compared to an animal group representing the total mean scores and to home-cage controls. It was established that anxious rats had a significantly lower number of benzodiazepine receptors in frontal cortex as compared to non-anxious animals and in hippocampus as compared to home-cage controls. There was also a decreased number of CCK-8 receptors in hippocampus of anxious rats as compared to the non-anxious and control groups. Non-anxious animals had a significantly lower number of CCK-8 receptors in frontal cortex than anxious and control rats. Acute treatment of rats with anxiogenic benzodiazepine inverse agonist FG 7142 (10 and 20 mg/kg) did not influence benzodiazepine binding in brain regions under investigation but caused upregulation of CCK-8 receptor binding in frontal cortex. On the other hand, CCK-8 analogues caerulein and pentagastrin, administered in doses which inhibit exploratory activity in plus-maze (100 or 500 ng/kg respectively), decreased the number of benzodiazepine binding sites in rat frontal cortex if injected intraperitoneally but did not affect CCK-8 binding. The present findings indicate that benzodiazepine and CCK-8 receptor binding characteristics in brain undergo rapid and behaviourally specific changes during stressful events.

Movement disorders in patients taking anticonvulsants

BACKGROUND

A wide variety of movement disorders may occur as a consequence of the administration of antiepileptic drugs (AEDs). Although it has been suggested that the risk of parkinsonism is 10-fold higher in those taking valproate as compared with other AEDs, there have been no large, systematic trials assessing this.

AIM

To establish more precisely the prevalence of and risk factors for developing parkinsonism associated with valproate use,and to assess the occurrence of movement disorders with the newer AEDs.

METHODS

Patients with epilepsy were recruited from the Toronto Western Hospital Epilepsy Clinic (University of Toronto, Toronto, Ontario, Canada). Each patient was examined by a movement disorder specialist who was blinded to the treatment status of the patient.

RESULTS

201 patients were included. Postural tremor was the most common movement disorder (45%), followed by parkinsonism (4.5%). The odds of having parkinsonism were 5 times higher with valproate than with other AEDs. No single factor predicted the presence of parkinsonism; however, many (5/9) of the patients concurrently used other drugs or had comorbidities that could have caused or exacerbated parkinsonism. None of the newer AEDs were clearly associated with the presence of movement disorders; however, the numbers were too small to make a formal analysis.

CONCLUSION

Although the risk of parkinsonism with valproate is higher than with other AEDs, it is lower than originally reported. The cases available were not enough to accurately comment on the prevalence of movement disorders with the newer AEDs.