bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐resolution separation of oligonucleotides and DNA sequencing reaction products by capillary electrophoresis with linear polyacrylamide and laser‐induced fluorescence detection
Authors: Chen Nong , Manabe Takashi , Terabe Shigeru , Yohda Masafumi , Endo Isao
Published: May 2005

By employing linear polyacrylamide (LPA) as a sieving matrix, oligonucleotides and DNA sequencing fragments have been separated by capillary electrophoresis. A commercially available apparatus equipped with a laser‐induced fluorescence (LIF) detection system has been utilized, but the capillary cartridge has been modified in order to set the capillaries without coiling. Single‐base resolution was achieved for a mixture of FITC‐labeled oligonucleotides [FITC‐p(dT)] up to 500 base‐long chains. Because of high resolution, minor components of FITC‐p(dT) have also been separated. The mobility differences between single‐base adjacent peaks of FITC‐labeled DNA sequencing fragments have been detected up to 520 base‐long fragments. These results confirmed that linear polyacrylamide is an excellent sieving matrix in DNA sequencing by capillary electrophoresis.
Investigation of acridinium labelling for chemiluminescence detection of peptides separated by capillary electrophoresis
Authors: Ruberto Michael A. , Grayeski Mary Lynn
Published: May 2005

An acridinium ester has been used to tag mixtures of peptides followed by separation by capillary electrophoresis with chemiluminescence detection. The labelling of the peptides was performed at the picomole level. The chemiluminescence reaction conditions were optimized for the acridinium tag resulting in CE separations performed on attomole amounts of tagged peptides. Baseline resolution was obtained for a separation of standard peptides. The detection sensitivity was found to improve when multiple acridinium labels were attached to the peptides. The effect of acridinium tagging on the migration rate of the peptides was also studied. The increased weight of the acridinium tagged analyte increased the run time and resolution of a separated tryptic digest without resulting in excessive band broadening.
Hydrofluorocarbon and perfluorocarbon mobile phases for capillary supercritical fluid chromatography
Authors: Blackwell John A. , Schallinger Luke E.
Published: May 2005

The eluotropic strength of several hydrofluorocarbon and perfluorocarbon supercritical fluids is examined using capillary supercritical fluid chromatography. The results obtained are compared with carbon dioxide, fluoroform, and carbon dioxide modified with 5% methanol. Various naphthalene derivatives are used to determine differences in functional group selectivity between these fluids. Specific hydrogen bonding interactions are observed between hydrogen bond donating hydrofluorocarbon fluids and naphthalene derivatives with hydrogen bond accepting functional groups. Unexpectedly, perfluorocarbon fluids are much stronger in eluotropic strength than carbon dioxide, fluoroform, or methanol‐modified carbon dioxide.
Gas chromatographic analysis of methadone in urine samples after solid phase microextraction
Authors: Chiarotti Marcello , Marsili Remo
Published: May 2005

The use of solid phase microextraction for quantitative analysis of methadone in urine is reported. The proposed procedure allows the extraction of methadone from a urine matrix, avoiding sample handling and saving evaporation of solvents and concentration steps. A fiber coated with polymethylsiloxane was employed for the extraction of methadone from urine and subsequently directly injected into the GUMS apparatus. Specific and reproducible results were obtained with high sensitivity.
Enantiomer separation of DNP‐amino acids by capillary electrophoresis using chiral buffer additives
Authors: Wistuba Dorothee , Diebold Heike , Schurig Volker
Published: May 2005

The direct enantiomeric analysis of six DNP‐amino acids by capillary electrophoresis is reported. This study describes a comparison of several chiral buffer additives. Both the natural proteins BSA, AGP, ovomucoid and casein, and the cyclic oligosaccharides α‐, β‐, and γ‐cyclodextrin were used as chiral selectors. For the first time, casein from goat milk was successfully applied for chiral discrimination. The influence of the modifier n‐propanol on chiral discrimination is demonstrated with BSA as a buffer additive.
Supercritical fluid extraction/gas chromatography with thermal desorption modulator interface and nitro‐specific detection for the analysis of explosives
Authors: Francis Eric S. , Wu Mingin , Farnsworth Paul B. , Lee Milton L.
Published: May 2005

Supercritical fluid extraction (SFE) can greatly reduce the sample preparation time of analytes in solid matrices. The on‐line coupling of SFE with high‐speed gas chromatography (GC) can further reduce the total analysis time. SFE has been coupled to GC with a thermal desorption modulator (TDM) interface. A thermal energy analyzer (TEA), a chemiluminescence detector which is specific for nitro and nitroso compounds, has been coupled to the system to analyze explosives in soil samples.

The use of organic modifiers to increase the solvation power of carbon dioxide was necessary for the extraction of various explosives, and did not adversely affect the performance of the system. Thermally labile compounds, however, such as the nitrate esters, were shown to decompose in the modulator before the chromatographic separation.

This method allows for the rapid analysis of relatively volatile and thermally stable nitro compounds from solid matrices. The system can be used for screening small samples in short periods of time. Total analysis can be completed in less than 10 minutes and requires only 200 mg of soil. The minimum detectable quantity for the analysis of 2,4‐DNT was found to be 2.6 ppb in an actual soil sample.
Separation of fullerenes with liquid crystal bonded silica phases in microcolumn high performance liquid chromatography
Authors: Saito Yoshihiro , Ohta Hatsuichi , Nagashima Hideo , Itoh Kenji , Jinno Kyokatsu , Pesek Joseph J.
Published: May 2005

The liquid chromatographic separation of C60 and C70 fullerenes with liquid crystal bonded silica phases was carried out and the separation performance was evaluated with various mobile phase compositions and column temperatures. The results clearly indicate that one liquid crystal bonded phase possesses better retention capability and separation power for these fullerene molecules than commercially available octadecylsilica (ODS) phases. The capacity factors of C60 and C70 were 2.82 and 8.46, respectively, with n‐hexane as the mobile phase.

In contrast to the normal temperature dependency of the retention of some polycyclic aromatic hydrocarbons (PAHs) versus column temperature, unusual behaviors for C60 and C70 have been observed with the liquid crystal phase.
Di‐tert‐butyldimethylsilylated cyclodextrins as chiral stationary phases: Thermodynamic investigations
Authors: Maas Birgit , Dietrich Armin , Beck Thomas , Börner Susanne , Mosandl Armin
Published: May 2005

Thermodynamic data, which are derived from measurements of separation factors at different temperatures for various chiral compounds, show some expected, but also some surprising effects concerning the mechanism of chiral recognition for the cyclodextrin derivatives investigated.
Separation strategies for the determination of residues of explosives in soils using micellar electrokinetic capillary chromatography
Authors: Mussenbrock Elmar , Kleiböhmer Wolfgang
Published: May 2005

Micellar electrokinetic capillary chromatography (MEKC) separation strategies for the determination of residues of explosives in soils are presented. Compared to former publications, the number of explosives determined was increased up to 24 compounds in which all EPA priority substances are included. Separation characteristics were investigated as a function of different organic modifiers. Using 1 vol% of methanol, separation was realized for all 24 compounds, including all of the isomers of the mono‐and dinitrotoluenes. Furthermore, the lipophilic and hydrophilic parts of the surfactant were varied, and the best separation characteristics were obtained with sodium dodecyl sulphate (SDS). Even the suitability of mixed micelles for the analysis of nitroaromatics was tested. With the help of mixed micelles consisting of SDS and the amphoteric surfactant SB‐12, separation of 22 out of 24 explosives was realized. With significantly changed selectivities, complete separation required less than 12 minutes.
Comparative study of colombian rue oils by high resolution gas chromatography using different detection systems
Authors: Stashenko E. E. , Villa H. S. , Combariza M. Y.
Published: May 2005

Volatile secondary metabolites from different parts (flowers, leaves, stems, and roots) of Colombian rue (Ruta graveolens) were obtained by combined steam distillation‐solvent extraction. The various oils were analyzed by means of GC using FID, NPD, or MSD. The chemical composition of the oils extracted from the aerial parts differed drastically from those extracted from the roots. 3‐Pyrrolidinol, 1,4‐dimethylpiperazine, and various 1,3‐benzodioxole derivatives were detected in the Colombian rue oil for the first time.
Resolution of ampholytes focused in a natural pH gradient moving in a tapered capillary
Authors: Šlais K.
Published: May 2005

Changes in the resolution of peaks of ampholytes during their migration and focusing in a natural pH gradient which moves electrophoretically in a tapered capillary are discussed. The influence of the capillary geometry on the needed potential drop as well as on the pressure drop accompanied by the renewing of the electrolytes is estimated. The expected performance of focusing according to the suggested model is related to that of focusing of the ampholytes in a pH gradient moving in a capillary of constant cross‐section.
Open crown ether polysiloxane stationary phases for capillary gas chromatography
Authors: Cai Lin‐Shuang , Wu Cai‐Ying , Han Hui‐Ming
Published: May 2005

In this paper, two new open crown ether polysiloxane stationary phases were prepared for capillary gas chromatography. Chromatographic characteristics, including column efficiency, operational temperature range, thermal stability, and polarity were studied. The open crown ether polysiloxane was found to have unique selectivity for alcohols, aromatic hydrocarbons, and nitrogen‐containing compounds. The separation mechanism and various thermodynamic parameters are discussed.
Preparation of silica porous‐layer open‐tubular columns using fused silica capillaries
Authors: Yun Hao , Markides Karin E. , Lee Milton L.
Published: May 2005

We report a simple method for the preparation of silica PLOT columns using fused silica capillaries. In this method, silica particles were suspended in a methylene chloride/pentane solution containing polymethylhydrosiloxane and passed through the capillary tubing. This caused the silica particles to be dynamically coated on the inner wall of the fused silica capillary. The column was dried and heated, which facilitated the simultaneous deactivation and bonding of a uniform mono‐layer of porous silica on the inner wall of the capillary tubing. These columns were used to separate light hydrocarbons, chlorinated hydrocarbons, and aromatic compounds.
Resolution effects of organic additives on the MEKC enantiomeric separations of tri aza aromatic ligand compounds of iron(II)
Authors: See Marjorie M. , Elshihabi Said , Burke John A. , Bushey Michelle M.
Published: May 2005

We have utilized micellar electrokinetic chromatography with sodium deoxycholate micelles to separate the enantiomers of bis(8‐((pyridine‐2‐methylene)amino)quinoline)iron(II) hexafluorophosphate, Fe(PMAQ)2(PF6)2, bis(8‐((pyridine‐2‐methylene)amino)lepidine iron(II) hexafluorophosphate, Fe(PMAL)2(PF6)2, and bis(1‐(2‐pyridinyl)ethylidine)‐8‐aminoquinoline iron(II) hexafluorophosphate, Fe(PEAQ)2(PF6)2. The influence of 13 water miscible organic additives on the resolution of each pair of enantiomers was investigated. Significant changes in resolution are seen depending upon the particular organic additive used in the separation buffer. In addition, the effects of acetone concentration on the resolution of these enantiomers in bile salt solution was investigated. Resolution for all three pairs of enantiomers is maximized in a buffer solution containing 15% acetone. © 1995 John Wiley & Sons, Inc.
Micro LC on cellulose triacetate (CTA): Influence of particle diameter and column temperature
Authors: Chen Jian , Steenackers Dirk , Sandra Pat
Published: May 2005

Fused silica columns (320 μm i.d.) were packed with 10 μm, 15–25 μm, and 25–40 μm microcrystalline cellulose triacetate (CTA) and the influence of the particle diameter on column efficiency was investigated. The dependence of retention, selectivity, resolution, and analysis time on column temperature was studied for the separation of several racemates on microcolumns packed with 15–25 μm CTA. © 1995 John Wiley & Sons, Inc.
Microwave extraction in analytical chemistry of pollutants: Chlorinated benzenes
Authors: Onuska Francis I. , Terry Ken A.
Published: May 2005

The microwave energy produced in a cavity of the magnetron was used to extract chlorinated benzenes from water samples. This dynamic extraction method employs a stream of helium. Results were compared with those obtained by liquid‐liquid and the large volume extractions. The microwave extraction provides results that are comparable with those obtained using other techniques, while offering the advantages of speed. The preconcentration factors are approx. 1000 and corresponding detection limits for 1 liter of water are in the pg/L range, when determination of individual polychlorinated benzene congeners is performed using HRGC/MS/ selected ion monitoring. © 1995 John Wiley & Sons, Inc.
In‐situ hydrolysis/methylation pyrolysis CGC for the characterization of polyaramides
Authors: Venema Arnold , Boom‐Van Geest Renie C. A.
Published: May 2005

Some parameters influencing the in‐situ methylation by tetramethylammonium hydroxide (TMAH) during pyrolysis have been investigated with model compounds and polyaramides. Both pyrolysis temperature and excess TMAH (pH effect) influence the methylation of carboxy‐, aromatic amino‐, and hydroxyl‐functional groups. While the solvent of TMAH, i.e., methanol or water hardly influenced the methylation of the model compounds, the solvent effect was significant for the polyaramides. This can be explained by assuming a transesterification mechanism rather than hydrolysis/methylation. N‐methylation prior to the decomposition of polyaramides also may not be excluded. © 1995 John Wiley & Sons, Inc.
On‐line LC‐GC transfer via a hot vaporizing chamber and vapor discharge by overflow; increased sensitivity for the determination of mineral oil in foods
Authors: Grob Konrad , Bronz Marianne
Published: May 2005

The modified LC‐GC transfer technique with concurrent eluent evaporation reduces losses of volatile components. The LC fraction is transferred by the LC pump. Evaporation occurs in a heated capillary into which a piece of wire is introduced. Vapors are discharged by overflow. This enables the reduction of the oven temperature to the minimum that prevents recondensation and to obtain more efficient phase soaking for the retention of volatile solutes. The technique was applied to improve sensitivity of the analysis of mineral oil in foods. © 1995 John Wiley & Sons, Inc.
Parallel column gas chromatography
Authors: Owens Patrick M. , Loehle David W. , Scott Beverly S. , Gonzalez Rodney S.
Published: May 2005

A parallel column gas chromatography (PCGC) methodology that simultaneously collects retention information on multiple stationary phases is presented. The multidimensional PCGC configuration links a precolumn in series with a set of parallel analytical columns (having different stationary phases) all connected to a single detector. GC peaks heartcut from the precolumn are detected as a series of peaks due to retention differences on parallel columns. This provides a GC retention pattern that is characteristic of the analyte, the stationary phase array, and the conditions of the analysis. PCGC peak patterns observed for groups of C8, C9, and C10 compounds are presented. The use of PCGC with infrared and mass spectral detectors is reported. A methodology to account for changes in GC operating parameters using relative retentions of analytes to internal standards is presented. The first use of thermodynamic retention parameters to model retention behavior on parallel analytical columns under different temperature profiles is presented. Retention predictions within 0.3‐0.6% of experimental values are reported. These results indicate that PCGC has potential as a general qualitative analysis tool. Future efforts to calibrate retention predictions, to transport PCGC results between instruments, and to optimize the number of parallel columns are proposed. © 1995 John Wiley & Sons, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Aqueous alkylation of anions for static headspace sampling with analysis by capillary gas chromatography‐mass spectrometry
Authors: Mulligan Kevin J.
Published: May 2005

The formation of ethyl derivative from anions and the conjugate bases of weak acids through the reaction with ethyl p‐toluenesulfonate in strongly basic aqueous systems was used as a precursor to analysis by static headspace sampling with capillary gas chromatography‐mass spectrometry. A host of materials are amenable to the technique including: cyanide, butyrate, caproate, fluoroacetate, iodide, and phenol. These analytes were used to study the performance of the system in relation to the behavior of commercially obtained ethyl derivatives. 18‐Crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane) effectively catalyzes the reaction which appears to require the presence of high concentrations (5 M) of a basic salt, such as potassium carbonate. A 1:1 (molar) mixture of dibasic and tribasic potassium phosphate effectively substitutes for potassium carbonate and provides improved performance for fluoroacetate while reducing interferences such as diethyl carbonate. Quantitative yields were obtained in the concentration range 0.05‐2 mM, except for cyanide which produced propionitrile with an efficiency of 55–80%. Fructose, at the 10% w/v level, exerted little influence upon the reaction. Calibration curves (selected ion monitoring) were linear between 0.001 and 1 mM. This approach extends the applicability of static headspace sampling and offers a potentially simple alternative to ion chromatography for complicated matrices. It should prove useful for confirming results obtained by other methods or for screening poorly characterized samples. © 1995 John Wiley & Sons, Inc.
Separation and fluorescence enhancement of dansyl amino acids assisted by γ‐cyclodextrin and bovine serum albumin as mobile phase additive in microcolumn liquid chromatography
Authors: Takeuchi Toyohide , Miwa Tomoo , Chu Jianhua
Published: May 2005

The effects of γ‐cyclodextrin and bovine serum albumin as mobile phase additives on fluorescence intensity and retention of dansyl amino acids (Dns‐AAs) have been examined in microcolumn liquid chromatography. Polymercoated mixed‐functional silica packings were employed for the separation column. The concentrations of the additives, acetonitrile, and buffer affected the signal intensity and retention of DNA‐AAs. The use of the mobile phase additives improved the detection limits by a factor of as much as 7.4. © 1995 John Wiley & Sons, Inc.
Evaluation of a spatial scanning laser fluorometric detector for capillary electrophoresis: Application to studies of band migration and dispersion
Authors: Clark Brian K. , Sepaniak Michael J.
Published: May 2005

We report herein the development and evaluation of modified capillary electrophoresis instrumentation with laser fluorometric detection which allows for the convenient and precise translation of the detection zone along the length of the separation column. This instrumentation is utilized for fundamental studies of band dispersion, analyte mobility alterations, sample stacking, and the determination of diffusion coefficients. The feasibility of using this instrumentation to improve the signal/noise ratio and decrease analysis time is also presented. DNA restriction digest separations employing soluble polymer buffer systems with oncolumn fluorescent labeling was used to illustrate the unique advantages of this experimental design.
Associative learning in degenerative neostriatal disorders: Contrasts in explicit and implicit remembering between Parkinson's and huntington's diseases
Authors: Sprengelmeyer R. , Canavan A. G. M. , Lange H. W. , Hömberg V.
Published: May 2005

The performances of 12 patients with Parkinson's disease (PD), 16 with Huntington's disease (HD), and young and old healthy controls were assessed on a number of tests of verbal and nonverbal declarative memory, on a test of nonmotor conditional associative learning (words and colors), and on a number of reaction time (RT) tasks. The RT tasks consisted of cued simple and choice reactions. The relationship between the precue and the imperative stimulus in the S1–S2 paradigm was nonarbitrary in the first series and arbitrary in the second series. The series with arbitrary S1–S2 associations was repeated across two successive blocks of trials. The rationale of the study was to investigate the function of the basal ganglia “complex loop,” and it was postulated that HD patients would show greater deficits because of greater involvement of the caudate nucleus. The patients with HD had the slowest RTs. Across the two blocks with arbitrary S1–S2 associations, the patients with HD but not PD nevertheless showed evidence of learning in their precued RTs. In contrast, the patients with PD were better able to remember the associations in free recall than were the HD patients. It is concluded that patients with PD have relatively greater deficits in procedural learning, whereas those with HD have relatively more impairments in declarative memory, and the greater level of cognitive impairment in HD overall is interpreted as being due to more serious damage to the caudate loop.
The abnormality of N30 somatosensory evoked potential in idiopathic Parkinson's disease is unrelated to disease stage or clinical scores and insensitive to dopamine manipulations
Authors: Onofrj M. , Fulgente T. , Malatesta G. , Ferracci F. , Thomas A. , Curatola L. , Bollettini F. , Ragno M.
Published: May 2005

We recorded short latency somatosensory evoked potentials (SEPs) to median nerve stimuli in 40 patients affected by idiopathic Parkinson's disease (PD) classified from I to IV on the Hoehn and Yahr disability scale. SEPs were recorded before and after chronic administration of L‐Dopa and bromocriptine, before and after acute administration of L‐Dopa. Fourteen patients experiencing wearing off and dystonic‐dyskinetic disturbances were recorded during the occurrence of these oscillations of their clinical status. Absent or reduced N30 components were found in 32.5% of patients. SEPs were not modified by acute or chronic administration of L‐Dopa or bromocriptine or during off and dystonic or dyskinetic conditions. Multiple correlations of N30 with scores of the Unified Parkinson's Disease Rating Scale showed that N30 abnormality did not classify patient with prominent clinical features, nor did it predict the outcome of treatment.
Effect of cisapride on response fluctuations in Parkinson's disease
Authors: Djaldetti Ruth , Koren Maya , Ziv Ilan , Achiron Anat , Melamed Eldad
Published: May 2005

Impaired gastric emptying may be the cause for some response fluctuations in Parkinson's disease (PD), especially the “delayed‐on” and “no‐on” phenomena. Cisapride is a prokinetic drug that enhances gastric emptying by releasing acetylcholine from the myenteric plexus. Tolerability and safety as well as efficacy of cisapride was studied in an open‐label trial on 15 fluctuating PD patients. Twelve patients had “delayed‐on” and six had “no‐on” phenomena. They filled out daily diaries on times of levodopa intake and of turning “on” and “off” for 1 week on levodopa alone and for an additional week of pretreatment with cisapride, 30 min before early morning, early afternoon, and late evening doses of levodopa. Cisapride significantly shortened latency to “on” from 60 ± 20 to 45 ± 19 min after the morning dose and from 63 ± 17 to 47 ± 22 min after the evening doses. Patients with “no‐on” phenomenon had a decreased number of dose failures from 23 before to nine during cisapride treatment. The drug was well tolerated, with no important side effects. Our study supports the role of impaired gastric emptying in some subtypes of motor fluctuations and indicates that they may be improved by prokinetic drugs.
International guide to drugs for Parkinson's disease
Authors: Oertel W. H. , Dodel R. C.
Published: May 2005

Pharmacotherapy of Parkinson's disease (PD) has become so effective that patients with PD can enjoy a nearly normal life, including travel for several years. The degree of international travel of patients with PD and in particular the recent increased coordination between health systems in the European community call for a detailed information on the different antiparkinsonian drugs available worldwide. To provide an overview for physicians and patients on the diversity of preparations available in the different countries, we compiled the most commonly used substances along with their size of dosage and formula in an international guide to drugs for PD.
Unique myoclonic pattern in corticobasal degeneration
Authors: Brunt Ewout R. P. , van Weerden Tiemen W. , Pruim Jan , Lakke Johannes W. P. F.
Published: May 2005

We describe two similar patients with a clinical diagnosis of corticobasal ganglionic degeneration (CBGD). After a period of increased action tremor, both patients developed a fixed posture in the right arm with a slow rhythmic myoclonus, which appeared to be caused by trains of highly synchronized and stimulus sensitive myoclonic discharges. Resetting of the spontaneous myoclonic discharges by peripheral and central stimulation and a jerklocked cortical potential were demonstrated in one case. The somatosensory evoked potentials (SEPs) showed abnormal parietal curves with small N20–P25 amplitudes and without giant SEP characteristics. The latencies of the cortical event and of the late responses, and the duration and distribution of the discharges compare best with those of the cortical reflex type of myoclonus. Localized parietal cortical damage, as indicated by clinical evidence and imaging techniques, may well explain the absence of a giant SEP in these patients with CBGD.
Reversible parkinsonian syndrome complicating cysticercus midbrain encephalitis
Authors: Verma Ashok , Berger Joseph R. , Bowen Brian C. , Sanchez‐Ramos Juan
Published: May 2005

We describe a clinical picture similar to Parkinson's disease in a patient with midbrain encephalitis due to cysticercosis. The clinical, radiographic, and cerebrospinal fluid findings suggested an inflammatory reaction to a dying cyst that involved midbrain structures. The encephalopathy appeared to worsen temporarily after the institution of anticysticercus therapy. A discordance between worsening parkinsonian symptoms and improving pyramidal features was noted. Virtually a complete clinical recovery eventually ensued.
Defects of cytochrome c oxidase in the substantia nigra of Parkinson's disease: An immunohistochemical and morphometric study
Authors: Itoh Kyoko , Weis Serge , Mehraein Parviz , Müller‐Höcker Josef
Published: May 2005

Defects of respiratory chain complexes were considered as possible pathogenetic mechanisms in Parkinson's disease (PD). Changes of cytochrome c oxidase (COX) in four different nuclei of the substantia nigra of 8 PD cases and 10 age‐matched controls were investigated by means of morphometry and immunohistochemistry. Pigmented neurons with COX defects were randomly distributed within the four nuclei of PD cases, but only in the posterolateral nucleus was the numerical density of pigmented neurons with COX defects significantly increased compared with controls. The numerical density of pigmented neurons without COX defects was significantly reduced in the anteromedial, anterointermediolateral, and posterolateral nuclei in PD. The cell size of pigmented neurons with and without COX defects was significantly diminished in the anteromedial and posterolateral nuclei of PD cases. It is suggested that complex IV defects in nigral neurons are most probably a result of accelerated aging, but are least likely to be a primary aspect of the pathogenetic processes occurring in PD.
Levodopa induces apoptosis in cultured neuronal cells—A possible accelerator of nigrostriatal degeneration in Parkinson's disease?
Authors: Ziv Ilan , Zilkha‐Falb Rina , Offen Daniel , Shirvan Anat , Barzilai Ari , Melamed Eldad
Published: May 2005

Apoptosis is an active, intrinsic cell suicide program. We recently suggested that it may have a role in the death of nigrostriatal dopaminergic neurons in Parkinson's disease (PD). We now report that levodopa, the current major therapy for PD, is a potent inducer of apoptosis in cultured postmitotic chick sympathetic neurons. Levodopa, in a concentration range of 0.01–0.3 mM, caused the characteristic apoptotic cascade of cell shrinkage, massive membrane blebbing, and nuclear fragmentation, as evident by nuclear flow cytometry and fluorescence microscopy. Levodopa‐induced apoptosis was inhibited by antioxidants, indicating that it may be mediated by autooxidation‐reactive species. Levodopa treatment for PD may therefore constitute an additional challenge for the defective apoptosis‐inhibiting systems in the nigrostriatal neurons. Despite reassuring data from some, but not all, previous studies, these findings suggest that the possible in vivo toxic effects of levodopa on the survival of the remaining nigral neurons should be further explored.
Movement disorders in adult hydrocephalus
Authors: Krauss Joachim K. , Regel Jens P. , Droste Dirk W. , Orszagh Miro , Borremans Jan J. , Vach Werner
Published: May 2005

In a prospective series of symptomatic adult hydrocephalus characterized by gait disturbance, cognitive impairment, and/or urinary incontinence, 88 of 118 patients (75%) had additional akinetic, tremulous, hypertonic, or hyperkinetic movement disorders. Their prevalence was highest in patients with idiopathic normal pressure hydrocephalus (NPH) of the elderly (56/65 patients, 86%), and they were less frequent in patients with secondary NPH (10/15, 66%), with nonhydrodynamic atrophic/other hydrocephalus (20/33, 61%), and with obstructive hydrocephalus/aqueductal stenosis (2/5, 40%). Akinetic symptoms were found in 73 of 118 patients (62%), and the most frequent movement disorder was upper extremity bradykinesia (55%). Akinetic, tremulous, hypertonic, and hyperkinetic movement disorders were exclusively secondary to causes not related to hydrocephalus in 24 of 118 patients (20%). The proportion of patients with movement disorders not attributable to only such causes was highest in the idiopathic NPH group (44/65, 68%). Thirteen of 118 patients (11%) presented with a parkinsonian syndrome. There was evidence for coexistent Parkinson's disease in four of these patients. Parkinsonism was found to be secondary to NPH in five patients and was found improved after shunting. Akinetic symptoms in patients with NPH generally responded favorably to CSF diversion, which was evident in 80% of a subset of this group. Various other movement disorders did not show definite improvement. The high prevalence of bradykinesia and other akinetic symptoms in NPH and the beneficial effect of shunting on such symptoms suggest that NPH may cause a more generalized disorder of motor function.
Comparison of transcranial sonography, magnetic resonance imaging, and single photon emission computed tomography findings in idiopathic spasmodic torticollis
Authors: Becker Georg , Naumann Markus , Scheubeck Maximilian , Hofmann Erich , Deimling Michael , Lindner Alfred , Gahn Georg , Reiners Christoph , Toyka Klaus V. , Reiners Karlheinz
Published: May 2005

Various lines of evidence suggest that the basal ganglia and thalamus are involved in the pathogenesis of idiopathic dystonia, but unfortunately neuroradiological and pathological data are sparse and controversial. In this study, we have examined 10 patients with spasmodic torticollis by neuroimaging techniques, including transcranial sonography (TS; n = 10), conventional (n = 10) and diffusion‐weighted (n = 5) magnetic resonance imaging (MRI), and single photon emission computed tomography (SPECT; n = 10), employing [123I]iodobenzamide (IBZM) as a ligand with a high affinity to the D2 receptor. In seven patients, TS showed small hyperechogenic lesions in the medial segments of the lentiform nucleus contralateral to the side of head deviation. In accordance with the site of TS abnormalities, diffusion‐weighted MRI displayed a hyperintense lesion in only one patient, while standard MRI of this area was normal in all patients. SPECT revealed a slight but statistically nonsignificant reduction of IBZM tracer uptake in an area corresponding to the dorsal portions of the striatum in 9 of the 10 patients. TS findings support the hypothesis that structural alterations of the pallidothalamic circuit contralateral to the side of head deviation are involved in the pathogenesis of idiopathic spasmodic torticollis. TS may be more sensitive in detecting basal ganglia alterations than MRI.
The variability in the clinical effect induced by botulinum toxin type A: The role of muscle activity in humans
Authors: Eleopra R. , Tugnoli V. , de Grandis D.
Published: May 2005

When botulinum toxin (BT) is administered for the first time at fixed doses, variable clinical responses can be observed in patients with the same form of dystonic disorder. Many factors may contribute to this phenomenon, including the variability in the rate of absorption of the drug. Animal experimental models (rat diaphragm preparation) have demonstrated an increased absorption of BT in the terminal nerve endings of the muscle under repetitive electrical stimulation, suggesting that “muscle activity” also may play an important role. The aim of our study was to evaluate in humans the role of the muscle activity on the variability of the effect induced by BT type A. Eleven patients with blepharospasm and idiopathic facial hemispasm were studied by using neurophysiologic techniques. In nine patients, both extensor digitorum brevis (EDB) muscles were injected with low (3 IU), fixed doses of type A BT. For the first 24 h after administration of the drug, periodic electrical stimulation of only one EDB was used. The subsequent percentage changes in compound muscle action potential (CMAP) amplitude was calculated at different intervals over a 30‐day period. The percentage change in the CMAP for the stimulated EDB was compared with that of the contralateral nonstimulated side. We found that the effect of the induced neuromuscular blockade was significantly greater for the stimulated side. In the other two patients, we injected BT in one EDB and the same volume of normal saline solution in the contralateral muscle to assess the stability of the CMAP in untreated muscle over time. We observed that the CMAP was unchanged in the untreated EDB; therefore we concluded that muscle activity plays an important role in the variability of clinical response often seen.
The effects of chronic levodopa treatment on pre‐ and postsynaptic markers of dopaminergic function in striatum of parkinsonian monkeys
Authors: Rioux Lise , Frohna Paul A. , Joyce Jeffrey N. , Schneider Jay S.
Published: May 2005

Therapeutic treatment of parkinsonian monkeys by chronic administration of levodopa (1‐DOPA) leads to the development of dyskinesias and other motor fluctuations. It is unclear whether there are alterations in the dopamine system that are related to the induction of dyskinesias by 1‐DOPA, but recent attention has focused on the D1 receptor system. The present study assessed the consequences of chronic 1‐DOPA treatment in monkeys made parkinsonian with 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) on indices of the pre‐ and post‐synaptic dopamine (DA) system. Treatment with therapeutic doses of 1‐DOPA led to the induction of dyskinesias in the MPTP‐treated monkeys. High‐pressure liquid chromatography was used for measurement of tissue levels of DA and its metabolites, and quantitative autoradiography was used to examine the regional integrity of the presynaptic DA system (by measuring [3H]mazindol binding to DA uptake sites). Quantitative autoradiography was used to measure the number of postsynaptic D1 receptors (using [3H] SCH 23390) in the striatum and pallidum of normal, MPTP alone, and MPTP monkeys treated chronically with 1‐DOPA. In both MPTP‐treated monkeys, levels of DA and metabolites as well as [3H]mazindol binding were greatly reduced in the caudate and putamen, slightly more in dorsal than in ventral areas. However, the lack of increase in striatal DA levels along with higher [3H]mazindol binding in MPTP‐plus‐1‐DOPA‐treated monkeys suggested differences in the way DA was used after 1‐DOPA treatment. In MPTP‐treated monkeys, a significant increase (141–170% of normals) of D1 receptor numbers was observed in putamen and dorsal caudate. With 1‐DOPA treatment, the number of D1 receptor numbers was further elevated in caudal putamen (119–123%), dorsal caudate (110–130%), and in the internal segment of the globus pallidus (GPi; 164% of normals) of MPTP‐treated monkeys as compared with MPTP treatment alone. This suggested that in MPTP‐treated monkeys made dyskinetic by chronic pulsatile delivery of 1‐DOPA, there was enhanced production of D1 receptors in the direct striatal output to the GPi.
The clinical features and prognosis of chronic posthypoxic myoclonus
Authors: Werhahn K. J. , Brown P. , Thompson P. D. , Marsden C. D.
Published: May 2005

The clinical and neurophysiologic features of 14 patients with chronic posthypoxic myoclonus are presented. Patients were first seen a mean of 2.5 years (range, 2 to 105 months) after the hypoxic event and followed up for 3.7 years (range, 7 to 84 months) thereafter. All patients had had a cardiorespiratory arrest, most caused by an acute asthmatic attack (11 cases). All patients had multifocal action myoclonus. Eleven patients had additional stimulus‐sensitive myoclonus. There was late improvement in the myoclonic syndrome and the level of disability in all but one patient. Three patients were eventually able to discontinue antimyoclonic medication, and five patients were able to walk unaided. Cognitive deficits were found in seven patients and were usually mild. Other neurologic deficits were rare. Electrophysiologic investigation confirmed cortical action myoclonus in every case, although this could be combined with cortical reflex myoclonus, an exaggerated startle response, or brainstem reticular reflex myoclonus. We conclude that posthypoxic myoclonus typically consists of multifocal cortical action myoclonus that improves with time. It is only rarely associated with severe additional neurologic deficit.
Facial myokymia in multiple system atrophy
Authors: Blunt S. B. , Khalil N. M. , Perkin G. D.
Published: May 2005

Two patients are described with clinical and neuroimaging features consistent with a diagnosis of multiple system atrophy (MSA). The patients are unusual in that facial myokymia became apparent clinically at some stage in their illness. In each patient, the nature and severity of the involuntary facial movements evolved over the course of the illness. Electrophysiologically the movement pattern was consistent with myokymia, and studies of blink‐reflex responses suggested that the myokymic discharges were of brainstem origin. Involuntary facial movements described as facial action myoclonus with electrical characteristics consistent with myoclonus have been described previously in hereditary olivopontocerebellar atrophy (OPCA). Our report describes electrical and clinical features of facial myokymia in MSA with electrical features suggesting hyperexcitability of the facial motorneurons in the brainstem. Such myokymic movements may occur more frequently in MSA than previously recognised but may be missed clinically because of their evolving nature.
Clinical and pharmacological differences in early‐ versus late‐onset Parkinson's disease
Authors: Arevalo G. Gomez , Jorge R. , Garcia S. , Scipioni O. , Gershanik O.
Published: May 2005

We evaluated whether patients with early‐onset Parkinson's disease (EOPD) have a different clinical profile and pharmacological response than those with late‐onset disease (LOPD). We performed a retrospective analysis and an acute pharmacological challenge with L‐Dopa in 34 EOPD (age at onset between 21 and 40 years) and 34 LOPD (onset after age 60) patients. All patients complete a structured questionnaire cross‐checked against mediacal record charts and underwent an acute levodopa test. Most significant differences were in the mode of onset, time to diagnosis, and degree of initial improvement. We did not observe differences with regard to motor fluctuations. The acute levodopa test showed no differences in latency to response onset between groups. However, the magnitude of the response was greater and the duration shorter in EOPD patients. Younger patients had greater reductions in bradykinesia scores, whereas posture/gait symptomatology was less responsive in older patients. The type and severity of dyskinesias also differed significantly between groups. Our findings suggest that central pharmacokinetics, pharmacodynamics, and, possibly, nondopaminergic systems play a role in the age‐related differences observed in Parkinson's disease.
Mitochondrial respiratory chain function in multiple system atrophy
Authors: Gu M. , Gash M. T. , Cooper J. M. , Wenning G. K. , Daniel S. E. , Quinn N. P. , Marsden C. D. , Schapira A. H. V.
Published: May 2005

Multiple system atrophy (MSA) is a clinicopathological entity distinct from idiopathic Parkinson's disease (PD) that is responsible for 5–10% of cases of parkinsonism. Degeneration of nigral neurones is a feature of both diseases. A specific deficiency of mitochondrial complex I activity has been found in PD substantia nigra. We have analysed mitochondrial function in substantia nigra and platelets from MSA patients to identify any respiratory chain defect in this disorder and to determine its tissue specificity. As our MSA patients had been on L‐DOPA, we also sought to establish whether this treatment could cause the complex I defect as seen in PD. We found no significant difference in respiratory chain activity corrected for mitochondrial mass between control and MSA patients in either of the tissues studied. These results provide a biochemical dimension to the differences between MSA and idiopathic PD. In addition, the fact that L‐DOPA failed to induce a complex I defect in MSA substantia nigra suggests that this treatment is unlikely to cause the complex I deficiency in PD, without additional factors that may operate in PD.
Cervical dystonia associated with tumors of the posterior fossa
Authors: Krauss Joachim K. , Seeger Wolfgang , Jankovic Joseph
Published: May 2005

Cervical dystonia was associated with posterior fossa tumors in three patients. The onset of dystonia paralleled the appearance of other focal neurologic signs. All patients had extra‐axial tumors located in the cerebellopontine angle that were removed via suboccipital approaches. The tumors were identified as schwannomas arising from the glossopharyngeal nerve and from the vagus/accessory nerves; and a meningioma. Postoperatively, the cervical dystonia improved markedly during a period of 8 years in one patient, and it remitted completely within 1 year in another patient. In the third patient, cervical dystonia persisted. The combination of the clinical findings and the temporal relationship of their appearance suggest a causal association between the posterior fossa tumors and cervical dystonia in these three cases. Possible pathogenic mechanisms are reviewed.
[123I]β‐CIT single‐photon emission tomography in DOPA‐responsive dystonia
Authors: Naumann Markus , Pirker Walter , Reiners Karlheinz , Lange Klaus , Becker Georg , Brücke Thomas
Published: May 2005

The radiotracer [123I]β‐CIT is a sensitive marker of dopamine uptake sites that can be used to visualize dopaminergic nerve endings in vivo in the human brain. We report on [123I]β‐CIT single‐photon emission computed tomography (SPECT) findings in a patient with DOPA‐responsive dystonia (DRD). [123I]β‐CIT SPECT showed a striatal radiotracer uptake in the upper range of normal, indicating intact dopamine transporters and structural integrity of nigrostriatal neurons. This differentiates DRD from clinically similar cases with juvenile‐onset parkinsonism with dystonia that have a considerably poorer prognosis. [123I]β‐CIT SPECT may provide a method equally as useful as fluorodopa positron emission tomography in DRD.
Sleep benefit in parkinson's disease
Authors: Merello Marcelo , Hughes Andrew , Colosimo Carlo , Hoffman Marion , Starkstein Sergio , Leiguarda Ramon
Published: May 2005

Sleep benefit (SB) In Parkinson's disease (PD) is not well characterized. To determine SB frequency, as well as to characterize and correlate it with other disease variables, we evaluated prospectively a consecutive series of 312 PD patients by means of a structured questionnaire: 55% reported having SB and 35% reported that awakening was their best time of the day. Because of SB, 21% of the entire population were able to skip or delay medication. The mean duration of the phenomenon was 85.4 ± 67 min. Patients with SB were significantly older (p < 0.0002), had disease longer (p < 0.05), and were often men (X2 = 3.5, df 1, p = 0.05). Patients with SB took sleep medication with similar frequency as those without SB. There were no differences in hours of sleep or sleep latency. Sleep problems such as nightmares or somnambulism, but not the number of sleep awakenings, were similar in both groups. In conclusion, SB is a frequent phenomenon, especially in men, elderly patients, and patients with longer disease duration. SB enables the morning L‐dopa dose to be postponed in ∼50% of patients.
Severe tardive dystonia: Treatment with continuous intrathecal baclofen administration
Authors: Dressler Dirk , Oeljeschläger Remt‐Otto , Rüther Eckart
Published: May 2005

Treatment of tardive dystonia with oral baclofen produces ambivalent and overall disappointing results. However, because only a small proportion of the baclofen penetrates into the central nervous system when administered orally, we tested whether it is possible to increase the efficacy of treatment by continuous intrathecal infusion of baclofen (CITB) in a patient with severe tardive axial dystonia unresponsive to conventional therapy. A dose of 100 m̈g/day improved muscle tone, head control, posture, and walking distance; electromyography showed a marked decrease of dystonic muscle activity with fully preserved voluntary muscle activity, and the patient reported substantial reduction of pain. Apart from some minor discomfort at the site of operation, no side effects were noted. Further studies should be encouraged to evaluate the usefulness of CITB for other patients with severe and otherwise untreatable tardive dystonia.