Restless legs syndrome?new insights into clinical characteristics, pathophysiology, and treatment options

We summarize recent advances in the clinical definition of restless legs syndrome (RLS), in understanding the basic mechanisms, and the successful treatments of RLS. New diagnostic instruments and severity scales have been developed for better phenotyping of the individual patient. Iron metabolism related components and the dopaminergic system have been extensively investigated in respect to the pathophysiology of RLS. The presence of mechanical hyperalgesia to pin-prick points towards an involvement of the nociceptive system. Genetic research has reported loci on chromosome 12q and 14q to play a role in the vulnerability to RLS. Placebo-controlled large-scale phase II and III treatment trials have shown that dopamine agonists are safe and efficacious agents for the treatment of this disorder.

Pharmacologically modulated fMRI--cortical responsiveness to levodopa in drug-naive hemiparkinsonian patients

According to the basal ganglia-thalamocortical circuit model, dopamine depletion in the nigrostriatal system leads to hypoactivation in the supplementary motor area (SMA) and the primary motor cortex (M1) in Parkinson's disease. This functional cortical deafferentation and its reversibility by levodopa (L-dopa) treatment has been established in previous studies for SMA but remains controversial for M1. We used functional MRI (fMRI) and a simple finger opposition task to correlate blood oxygenation level-dependent (BOLD) signal changes with motor performance, assessed separately for each hand between fMRI scanning sessions. Eight drug-naive patients with an akinetic idiopathic hemiparkinsonian syndrome (Hoehn and Yahr stage 1-1.5) and 10 healthy controls were studied. Patients performed a simple, auditory-paced random finger- opposition task every 3 s before and repeatedly every 20 min after intake of 300 mg of fast-release L-dopa. M1 contralateral to the affected hand and SMA, predominantly of the contralateral side, showed a BOLD signal increase after L-dopa intake. Furthermore, comparing BOLD responses of M1 and SMA between the patients and controls revealed that these areas were hypoactive before L-dopa treatment. Signal changes in M1 and SMA were highly correlated with motor performance, which increased after L-dopa intake. This result is not confounded by a performance effect because the motor task employed during scanning was identical throughout all sessions. In contrast to previous imaging studies in which cortical reorganization in Parkinson's disease was thought to have caused M1 hyperactivation, our data are in accordance with the hypothesis that, in de novo idiopathic hemiparkinsonian syndrome, motor cortex hypoactivation in contralateral M1 and bilateral SMA is caused by a decreased input from the subcortical motor loop, which is reversible by L-dopa.

[Treatment of hip adductor spasticity with botulinum toxin type B]

For the treatment of focal spasticity using botulinum toxin, only studies using type A have been published. Botulinum toxin type B (Neurobloc) is registered for cervical dystonia, but there is increasing interest in ist effectiveness for treating other diseases. Four patients, each with seriously disabling hip adductor spasticity of different origins, were treated with botulinum toxin type B following the failure of other therapeutic options. Total doses of 10,000 IU to 22,000 IU were injected bilaterally into the hip adductor muscles. A reduction in muscle tone or painful spasms was observed in all patients within 2 weeks, leading to an improvement in gait and increased ease of nursing care. Therefore, botulinum toxin type B may be a more cost-effective treatment for hip adductor spasticity than botulinum toxin type A.

Deep-brain stimulation for Parkinson's disease

Deep brain simulation (DBS) is a powerful new therapeutic approach for patients with Parkinson's disease. However, patient selection is critical for a valuable therapeutic result. Dopa sensitivity of the target symptoms, severe disability and low neurosurgical risks are among the major criteria for this indication. Other criteria like age or cognition must still be addressed in future prospective studies. The preferred target for DBS in PD is the subthalamic nucleus for various good reasons. However, prospective studies for this procedure are lacking and some clinical problems may be more easily solved with targeting the internal pallidum or the thalamus. Despite major progress in this field, much work remains to be done.

COMT-inhibition increases serum levels of dihydroxyphenylacetic acid (DOPAC) in patients with advanced Parkinson's disease

Inhibition of the catechol-O-methyltransferase (COMT) is an effective treatment for end-of-dose fluctuations in advanced Parkinson's disease. The aim of the present investigation was to analyse the consequences of subsequent alterations in levodopa metabolism under common treatment conditions when the levodopa dose is adjusted due to the occurrence of dyskinesias after initiation of the COMT-inhibitor. Ten patients with advanced Parkinson's disease (Hoehn & Yahr stage IV) were medicated with tolcapone. Prior to and five to ten days after the initiation of tolcapone 300 mg/d, serum level profiles of levodopa and its metabolites (3-O-methyldopa (3-OMD), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA)) were performed. The mean daily levodopa dose was reduced from 894 +/- 248 mg to 646 +/- 252 mg (p = 0.003). There was a significant increase in the area under the curve (AUC) of DOPAC during COMT-inhibition compared to the baseline profile (p = 0.009). There were significant decreases of the AUC of HAV (p = 0.001) and the ratios of the AUC HVA / AUC DOPAC (p = 0.0001) and AUC 3-OMD / AUC levodopa (p = 0.0001).

CONCLUSION

The elevation of DOPAC and the decrease of HVA and HVA / DOPAC reflect a shift of the levodopa metabolism towards the MAO-B dependent oxidative pathway. This might contribute to production of hydroxyl radicals and induction of oxidative stress.

McLeod neuroacanthocytosis: genotype and phenotype

McLeod syndrome is caused by mutations of XK, an X-chromosomal gene of unknown function. Originally defined as a peculiar Kell blood group variant, the disease affects multiple organs, including the nervous system, but is certainly underdiagnosed. We analyzed the mutations and clinical findings of 22 affected men, aged 27 to 72 years. Fifteen different XK mutations were found, nine of which were novel, including the one of the eponymous case McLeod. Their common result is predicted absence or truncation of the XK protein. All patients showed elevated levels of muscle creatine phosphokinase, but clinical myopathy was less common. A peripheral neuropathy with areflexia was found in all but 2 patients. The central nervous system was affected in 15 patients, as obvious from the occurrence of seizures, cognitive impairment, psychopathology, and choreatic movements. Neuroimaging emphasized the particular involvement of the basal ganglia, which was also detected in 1 asymptomatic young patient. Most features develop with age, mainly after the fourth decade. The resemblance of McLeod syndrome with Huntington's disease and with autosomal recessive chorea-acanthocytosis suggests that the corresponding proteins--XK, huntingtin, and chorein--might belong to a common pathway, the dysfunction of which causes degeneration of the basal ganglia.

The chorea of McLeod syndrome

Among the movement disorders associated with acanthocytosis, McLeod syndrome (McKusick 314850) is the one that is best characterized on the molecular level. Its defining feature is low reactivity of Kell erythrocyte antigens. This is due to absence of membrane protein KX that forms a complex with the Kell protein. KX is coded for by the XK gene on the X-chromosome. We present six males (aged 29 to 60 years), with proven XK mutations, to discuss the chorea associated with McLeod syndrome. The movement disorder commonly develops in the fifth decade and is progressive. It affects the limbs, the trunk and the face. In addition to facial grimacing, involuntary vocalization can be present. In early stages there may only be some restlessness or slight involuntary distal movements of ankles and fingers. Lip-biting and facial tics seem more common in autosomal recessive choreoacanthocytosis linked to chromosome 9. This, together with the absence of dysphagia in McLeod syndrome, may help in differential diagnosis. Recent findings suggest a role for the endothelin system of the striatum in the pathogenesis of McLeod syndrome.

Reduction of striatal glucose metabolism in McLeod choreoacanthocytosis

McLeod syndrome is a distinct form of neuroacanthocytosis. Its defining feature is the depression of erythrocyte Kell antigens. The underlying X chromosomal mutations cause a dysfunction of an erythrocyte membrane protein Kx. A choreatic movement disorder with caudate atrophy in CT and MRI has been reported in McLeod syndrome later in the course of the disease. Positron emission tomography with 18F-deoxyglucose (FDG) was performed in two unrelated affected men. In the older patient, progressive chorea was seen from the 5th decade. In the second patient there were no signs of a movement disorder at the age of 28. Positron emission tomography disclosed a reduction of the striatal FDG uptake in both patients, with accentuation in patient 1. Frontal lobe metabolism was not affected. Basal ganglia dysfunction with early impairment of striatal glucose metabolism thus seems obligatory for McLeod syndrome, as found in other forms of chorea with or without acanthocytosis.

Pleural fibrosis associated with dihydroergocryptine treatment

OBJECTIVES

This is the first report of a histologically confirmed pleuropulmonary fibrosis (PPF) associated with the dopamine agonist dihydroergocryptine.

CASE REPORT

A 67-year-old male patient with Parkinson's disease developed a severe restrictive pulmonary disorder with dyspnea and nonproductive cough after a daily intake of 45 mg dihydroergocryptine for 2 years. After changing the dopamine agonist to the non-ergoline substance pramipexole, marked improvement of the clinical symptoms of PPF occurred, while radiological signs showed only a moderate decrease.

CONCLUSION

PPF is a possibly fatal complication. Chest X-rays and specific pneumological diagnostics should be done if typical symptoms or nonspecific signs of PPF occur while a patient is on treatment with an ergoline dopamine agonist.

Prolonged postexcitatory inhibition after transcranial magnetic stimulation of the motor cortex in patients with cerebellar ataxia

Postexcitatory inhibition after transcranial magnetic stimulation of the motor cortex (silent period, SP) is supposed to be predominantly mediated by the activation of inhibitory cortical interneurons. Cortical excitability seems to be reduced in patients with cerebellar ataxia. Motor threshold, central motor conduction time and the duration of the silent period after a single magnetic stimulus to the motor cortex on both sides were measured in five patients with cerebellar ataxia of different origin and 18 healthy controls. Duration of SP was highly significantly prolonged in patients compared with controls (P<0.001) while motor threshold and central motor conduction times were not different. Fifteen of 18 control subjects showed late EMG responses after magnetic stimulation but none of the patients did (P<0.001). These findings support the hypothesis that cerebellar lesions activate inhibitory cortical interneurons or cause a disruption of a normally tonic cerebellar excitation to the motor cortex. Silent period measurement appears to be a sensitive diagnostic tool in the neurophysiological examination of cerebellar diseases.

Polyacrylic acid/polyvinylpyrrolidone bipolymeric systems. I. Rheological and mucoadhesive properties of formulations potentially useful for the treatment of dry-eye-syndrome

For the treatment of dry-eye-syndrome preparations containing polymers as active agents are used. Polyacrylic acid (PAA) is a well known mucoadhesive polymer. For ocular use, however, the very high viscous gel systems can cause irritation post application which can result in a low patient compliance. In this study we have shown that it is possible to formulate PAA based low viscous formulations with polyvinylpyrrolidone (PVP) as 2nd polymer. The survey of the systems for the parameters microviscosity with polarization and oscillatory rheology shows that the 2nd polymer influences the structure of the PAA gel framework that causes the significant decrease in apparent viscosity of the combination. The mucoadhesion and rheological characteristics were determined by means of rheological methods. The acquired results, low viscosity and a high mucoadhesion index in comparison with the monopolymer PAA preparation and with two PAA containing commercial artificial tear preparations, Vidisic and Thilo Tears, led to the conclusion that the combination of the two polymers, PAA and PVP, could be advantageous for the treatment of the dry eye.

Hyperammonaemic encephalopathy after initiation of valproate therapy in unrecognised ornithine transcarbamylase deficiency

Ornithine transcarbamylase deficiency is an X linked disorder and the most common inherited cause of hyperammonaemia. Fluctuating concentrations of ammonia, glutamine, and other excitotoxic amino acids result in a chronic or episodically recurring encephalopathy. A heterozygous female patient first presented with protein intolerance, attacks of vomiting, and signs of mental retardation in early childhood. At the age of 16 complex partial seizures occurred which were treated with sodium valproate. Seven days after initiation of valproate therapy, she developed severe hyperammonaemic encephalopathy with deep somnolence. The maximum concentration of ammonia was 480 micromol/l. After withdrawal of valproate, three cycles of plasma dialysis, and initiation of a specific therapy for the inborn metabolic disease, ammonia concentrations fell to normal values. The patient remitted, returning to her premorbid state. Valproate can cause high concentrations of ammonia in serum in patients with normal urea cycle enzymes and may worsen a pre-existing hyperammonaemia caused by an enzymatic defect of the urea cycle. Sufficient diagnostic tests for the detection of metabolic disorders must be performed before prescribing valproate for patients with a history of encephalopathy.

[Acute reversible encephalopathy with brain edema and serial seizures in pseudohypoparathyroidism]

A 16 year old patient with the typical clinical signs of Albright's hereditary dystrophia developed series of epileptic seizures with loss of consciousness, tonic muscle contractions and bite of the tongue. After termination of the seizures there was coma without focal neurological signs. CT scan revealed diffuse brain edema. Electroencephalographic studies showed generalized slowing. In laboratory tests the only abnormalities were marked hypocalcemia (1.15 mmol/l) and hyperphosphatemia. Blood parathyroid hormone (PTH) was elevated. PTH-Test confirmed the diagnosis of pseudohypoparathyroidism. The patient was treated with calcium and 1,25-dihydroxy-cholecalciferol. After few days the severe encephalopathy, CT and electroencephalographic changes were completely reversible. Hereditary disturbances of the parathyroid hormone metabolism are rare diseases. Hypocalcemia must be included into the differential diagnosis of seizures and brain edema to avoid invasive diagnostic and irrational treatment.

Cognitive impairment, dementia and psychosocial functioning in human immunodeficiency virus infection. A prospective study based on DSM-III-R and ICD-10

Progressive cognitive impairment in human immunodeficiency virus (HIV) infection, called acquired immunodeficiency syndrome (AIDS) dementia complex (ADC), significantly influences the social prognosis of afflicted patients. The frequency and character in different stages of the infection are controversially discussed. In previous studies, differences in the selection of patients and methods of testing led to widely differing results. For these reasons, in the present prospective study on 45 HIV-infected patients, a structured psychiatric interview (SIDAM) was conducted based on the algorithm of diagnosing dementia in DSM-III-R and the ICD-10 guidelines. The psychopathological findings are expressed in syndrome scores; the results are summarized in a total score (SISCO). The interview contains the Mini-Mental State Examination. The degree of psychosocial functioning was estimated on the global assessment of functioning, Axis V of DSM-III-R. In stages preceding AIDS, only slight cognitive dysfunction was found compared with age- and education-matched normal controls, and this caused no relevant disturbance of psychosocial functioning. In 9 patients with manifest AIDS, dementia was diagnosed with DSM-III-R criteria and ICD-10 guidelines (30% of the AIDS patients). They showed marked impairment of intellectual ability, memory, verbal ability and calculation and constructional ability and fewer cortical focal symptoms (aphasia and apraxia). Corresponding to previous studies, major cognitive dysfunction in HIV infection can be characterized as subcortical dementia.

[Incidence of psychiatric syndromes and the psychosocial functional level of patients with HIV-1 infection]

There are not yet unselected studies on psychopathological syndromes in the course of HIV-infection in German-speaking countries. In a group of 55 patients in different stages of the infection two psychiatric explorations were done within an interval of about one year. The findings were analysed by the Brief Psychiatric Rating Scale (BPRS). The degree of psychosocial functioning was estimated using the GAF-scale (axis 5 of DSM-III-R). The diagnosis of dementia was based on DSM-III-R-criteria. Most of the patients (72%) showed normal or only slightly remarkable psychopathologic findings at both times. A significant increase in psychopathologic conspicuousness in the course of the disease was only found for the subscore BPRS 2 ("anergia"). Dementia was seen in five patients (9%) and only in the stage of manifest immune deficiency syndrome (WR 6). All-together there was only a slight decrease of psychosocial functioning detectable (median on the GAF-scale 75), which only in dementia showed a significant reduction.

Effects of helodermin on fetal rat bone metabolism in vitro

Helodermin belongs to the VIP family of polypeptides. Recent in vivo data suggest that helodermin-like peptides might be involved in the regulation of calcium metabolism. We show that helodermin specifically binds to a secretin-type receptor in osteoblast-like cells from fetal rat calvaria and increases the basal and PTH-stimulated cAMP concentration of these cells. In organ cultures of fetal rat calvaria, helodermin strongly inhibits bone matrix apposition and augments PTH-induced bone resorption. Helodermin-like peptides may thus be capable of enhancing the direct effects of PTH on bone metabolism.

Stimulation of bone matrix apposition in vitro by local growth factors: a comparison between insulin-like growth factor I, platelet-derived growth factor, and transforming growth factor beta

Many recent in vitro studies have shown effects of insulin-like growth factor I (IGF I), platelet-derived growth factor (PDGF), and transforming growth factor-beta (TGF beta) on the proliferation and differential functions of bone-forming osteoblasts; however, the question whether these factors might ultimately lead to a net increase or decrease in bone formation has been difficult to assess. In this study, we have used an autoradiographic method based on the incorporation of [3H]proline into freshly synthesized bone matrix to determine the overall effects of these factors on bone matrix apposition in 21-day-old fetal rat calvariae. IGF I, PDGF, and TGF beta increased bone matrix apposition in a dose-dependent manner up to 2-fold within 48 h. In addition, they partially or completely reversed the inhibition of bone matrix apposition observed with PTH. Exogenously added TGF beta was significantly more potent than equimolar concentrations of PDGF or IGF I in stimulating bone formation. Matrix apposition was greatest when IGF I, PDGF, and TGF beta were added simultaneously to the culture medium, indicating that these factors can enhance each other in stimulating bone formation. In conclusion, our results provide direct evidence that IGF I, PDGF, and TGF beta are capable of stimulating bone formation in vitro.

[Central motor conduction time in multiple sclerosis: an comparison of visual and somatosensory evoked potentials in relation to the type of disease course]

The central motor conduction time (CMCT) was measured by electrical transcranial and spinal stimulation in 70 consecutively admitted patients with definite multiple sclerosis and 26 normal volunteers. The results of the patientgroup were compared with visual and somatosensory (median and tibial nerve) evoked potentials. The mean CMCT of the volunteers was 5.4 ms versus 11.1 ms in the patient group. In 55 of the 70 patients (79%) the CMCT was delayed (p less than 0.0001). VEP showed pathologic results in 67%, SEP of tibial nerve in 51%, SEP of median nerve in 41% of the patients. In 10 of the 70 cases (15%) only CMCT was pathologic. Especially in the first attack of the disease the CMCT (79% pathologic results) was superior in comparison to the evoked potentials (VEP and SEP together 43% pathologic findings). In our cases without clinical evidence of a pyramidal tract lesion a subclinical affection of this pathway could be determined in 69% by a pathologic CMCT. We regard this method therefore as a valuable tool in the early diagnosis of multiple sclerosis.