bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orthostatic tremor arises from an oscillator in the posterior fossa
Authors: Wu Y.R. , Ashby P. , Lang A.E. 
Published: August 2002

AbstractWe tested the hypotheses that orthostatic tremor is generated by a central oscillator and that the tremor is expressed through spinal Ib interneurons. Six patients with orthostatic tremor were examined. The tremor was reset by electrical stimulation over the posterior fossa at intensities that were below the threshold for a motor evoked potential (MEP) but was not reset by transcranial magnetic stimulation over the motor cortex that did produce an MEP. It is argued that the oscillator involves the cerebellum or brainstem.The inhibition of voluntary EMG produced by stimulation over tendons, which has been attributed to effects from Golgi tendon organs (GTO), was not modulated in synchrony with the tremor. We were unable to demonstrate, therefore, that the tremor is expressed through GTO interneurons with this method. © 2001 Movement Disorder Society.
Serum leptin concentrations and satiety in Parkinson's disease patients with and without weight loss
Authors: Evidente Virgilio G.H. , Caviness John N. , Adler Charles H. , Gwinn‐Hardy Katrina A. , Pratley Richard E. 
Published: August 2002

AbstractWe compared serum leptin and satiety measures in 18 Parkinson's disease (PD) patients with unintended weight loss (WL) and 18 PD patients whose weight was stable (WS). Mean serum leptin concentrations tended to be lower in WL than WS patients, but this did not reach statistical significance. Body mass index correlated with serum leptin concentrations. Ratings of hunger, satiety, fullness, and thirst did not differ between groups. However, the mean sensation of fullness before meals correlated with serum leptin in the entire cohort of patients, particularly in the WL group. The results indicate that unintended weight loss in PD patients is unlikely to be due to abnormal serum leptin concentrations. © 2001 Movement Disorder Society.
Rigidity decreases resting tremor intensity in Parkinson's disease: A [123I]β‐CIT SPECT study in early, nonmedicated patients
Authors: Winogrodzka Ania , Wagenaar Robert C. , Bergmans Paul , Vellinga Astrid , Booij Jan , van Royen Eric A. , van Emmerik Richard E.A. , Stoof Johannes C. , Wolters Erik Ch. 
Published: August 2002

AbstractTremor is one of the clinical hallmarks of Parkinson's disease (PD). Although it is accepted that other classic symptoms of PD such as rigidity and bradykinesia result from a degeneration of the nigrostriatal system and subsequent reduction in striatal dopamine, the pathophysiology of resting tremor remains unclear. The majority of recent single photon emission computed tomography (SPECT) and positron emission tomography (PET) studies, using various radioligands, demonstrated significant correlation between striatal radioligand bindings and the degree of parkinsonian symptoms such as rigidity and bradykinesia, but not tremor. We investigate the relationship between the degeneration of the nigrostriatal pathway and the appearance of resting tremor, taking into account the possible interference of rigidity with the resting tremor. Thirty early and drug‐naïve PD patients were examined. Tremor and rigidity of the arms were assessed using UPDRS, and the power of tremor was estimated using spectral analysis of tremor peaks. [123I]β‐CIT SPECT was used to assess degeneration of the dopaminergic system in PD patients. A comparison between asymmetry indices showed that in terms of both tremor and rigidity, the most affected arm corresponded significantly with the contralateral striatum, having the largest reduction in radioligand binding. Furthermore, tremor power accounted for a significant part of variance in the contralateral striatum, suggesting a relationship between this PD symptom and the degeneration of the dopaminergic system. Further, the degree of tremor was reduced with increasing rigidity. However, correcting for the influence of rigidity, the significant contribution of tremor in the variance in the contralateral striatal [123I]β‐CIT binding disappeared. When the confounding influence of rigidity is taken into account, no significant direct relationship between dopaminergic degeneration and the degree of tremor could be found. Other pathophysiological mechanisms should be similarly investigated in order to further our understanding of the origin of resting tremor in PD. © 2001 Movement Disorder Society.
Long‐Term follow‐up on restless legs syndrome patients treated with opioids
Authors: Walters Arthur S. , Winkelmann Juliane , Trenkwalder Claudia , Fry June M. , Kataria Vandana , Wagner Mary , Sharma Rakesh , Hening Wayne , Li Liren 
Published: August 2002

AbstractThe medical records of 493 patients with restless legs syndrome (RLS) from three major centers were studied to determine the number and outcome of patients who had been treated with opioids as a monotherapy. At one time or another 113 patients (51 men, 62 women; age range, 37–88 years) had been on opioid therapy either alone (36 patients) or with opioids added secondarily to other medications used to treat RLS (77 patients). Twenty‐three of the 36 opioid monotherapy patients had failed dopaminergic and other therapeutic agents prior to the initiation of opioid monotherapy. Twenty of the 36 opioid monotherapy patients continue on monotherapy for an average of 5 years 11 months (range, 1–23 years), despite their knowledge of the availability of other therapies. Of the 16 patients who discontinued opioids as a sole therapy, the medication was discontinued in only one case because of problems related to addiction and tolerance. Polysomnography on seven patients performed after an average of 7 years 1 month of opioid monotherapy (range, 1–15 years) showed a tendency toward an improvement in all leg parameters and associated arousals (decrease in PLMS index, PLMS arousal index, and PLM while awake index) as well as all sleep parameters (increase in stages 3 and 4 and REM sleep, total sleep time, sleep efficiency, and decrease in sleep latency). Two of these seven patients developed sleep apnea and a third patient had worsening of preexisting apnea. Opioids seem to have long‐term effectiveness in the treatment of RLS and PLMS, but patients on long‐term opioid therapy should be clinically or polysomnographically monitored periodically for the development of sleep apnea. © 2001 Movement Disorder Society.
Toxicity of Annonaceae for dopaminergic neurons: Potential role in atypical parkinsonism in Guadeloupe
Authors: Lannuzel Annie , Michel Patrick P. , Caparros‐Lefebvre Dominique , Abaul Jacqueline , Hocquemiller Reynald , Ruberg Merle 
Published: August 2002

AbstractIn the French West Indies there is an abnormally high frequency of levodopa‐resistant parkinsonism, suggested to be caused by consumption of fruit and infusions of tropical plants, especially Annona muricata (corossol, soursop). To determine whether toxic substances from this plant can cause the neuronal degeneration or dysfunction underlying the syndrome, we exposed mesencephalic dopaminergic neurons in culture to the total extract (totum) of alkaloids from Annona muricata root bark and to two of the most abundant subfractions, coreximine and reticuline. After 24 hours, 50% of dopaminergic neurons degenerated with 18 μg/ml totum, 4.3 μg/ml (13 μM) coreximine, or 100 μg/ml (304 μM) reticuline. The effects of the alkaloid totum were not restricted to the population of dopaminergic cells since GABAergic neurons were also affected by the treatment. Nuclei in dying neurons showed DNA condensation or fragmentation, suggesting that neuronal death occurred by apoptosis. Cell death was not excitotoxic and did not require toxin uptake by the dopamine transporter. Neurodegeneration was attenuated by increasing the concentration of glucose in the culture medium, which also reduced the effect of the dopaminergic neurotoxin MPP+, a mitochondrial respiratory chain inhibitor. Toxin withdrawal after short‐term exposure arrested cell death. Acute treatment with totum, coreximine, or reticuline reversibly inhibited dopamine uptake by a mechanism that was distinct from that causing neuronal death. GABA uptake was not reduced under the same conditions. This study suggests that alkaloids from A. muricata can modulate the function and the survival of dopaminergic nerve cells in vitro. It is therefore conceivable that repeated consumption could cause the neuronal dysfunction and degeneration underlying the West Indian parkinsonian syndrome. © 2002 Movement Disorder Society.
Cell surface heparan sulfate and its roles in assisting viral infections
Authors: Liu Jian , Thorp Suzanne C. 
Published: August 2002

AbstractHeparan sulfate, a highly sulfated polysaccharide, is present on the surface of mammalian cells and in the extracellular matrix in large quantities. The sulfated monosaccharide sequences within heparan sulfate determine the protein binding specificity and regulate biological functions. Numerous viruses and parasites utilize cell surface heparan sulfate as receptors to infect target cells. Due to the structural complexity of heparan sulfate, it was considered a nonspecific cell surface receptor by interacting with the positive motifs of viral proteins. However, recent studies reveal that heparan sulfate plays multiple roles in assisting viral infection, and the activities in promoting viral infections require unique monosaccharide sequences, suggesting that heparan sulfate could serve as a specific receptor for viral infection. The currently available techniques for the structural analysis of heparan sulfate provide essential information about the specific roles of heparan sulfate in assisting viral infections. The knowledge accumulated in this fast growing field will permit us to have a better understanding of the mechanism of viral infection and will lead to the development of new antiviral agents. © 2001 John Wiley & Sons, Inc. Med Res Rev, 22, No. 1, 1–25, 2002
Structure of metal adducts of anthracyclines probed by absorption, circular dichroism and paramagnetic NMR
Authors: Di Bari Lorenzo , Pintacuda Guido , Ripoli Silvia , Salvadori Piero 
Published: August 2002

AbstractA structural study of metal ion adducts of a new anthracycline disaccharide (MEN 10755) was undertaken. The trivalent lanthanide ion Yb(III) was employed as paramagnetic structural probe for 1H NMR analysis. Through a comparative spectroscopic investigation [UV–Vis absorption and circular dichroism (CD), 1H NMR], the isomorphism between its adducts with lanthanide ions (La3+, Yb3+, Lu3+) and calcium (one of the most representative biological cations) was verified. Solution behavior and cation binding were also investigated by means of optical titrations. In agreement with other anthracyclines, MEN 10755 was found to dimerize in aqueous solution [estimated Kdim (pH7.6) = 7 × 103], but not in methanol. A prevalent complex Yb3+–MEN 10755 (1:1) in both buffered aqueous and methanolic solutions (estimated Kcompl = 2100 M−1) was observed. A numerical analysis of the LIR and LIS 1H NMR literature data for a similar adduct (Yb3+–daunorubicin) was performed using newly developed software, PERSEUS (Paramagnetic Enhanced Relaxation and Shifts for Eliciting Ultimate Structures), and the structure of the complex was characterized, locating definitely the binding site on the O‐11, O‐12 quinone system. The components of the anisotropic part of the magnetic susceptibility tensor were also determined. Finally, a study of the time‐dependent formation of an Yb3+–MEN 10755 complex through 1H NMR, UV–Vis CD and induced NIR CD was carried out. Copyright © 2002 John Wiley & Sons, Ltd.
Preferential solvation of a tetrapeptide by trifluoroethanol as studied by intermolecular NOE
Authors: Díaz M. Dolores , Berger Stefan 
Published: August 2002

AbstractHomonuclear and heteronuclear intermolecular NOE measurements were applied to study the solvation of a short model tetrapeptide, NAc‐Ser‐Phe‐Val‐Gly‐OMe, dissolved in water, in trifluoroethanol (TFE) and in mixtures of both. Site specificity of homonuclear NOEs between water and different protons of the peptide was proved. Preferential solvation of the peptide by TFE in water–TFE mixtures was demonstrated by a significant decrease in water–peptide interaction and a concomitant buildup of heteronuclear NOE between the fluorine atoms of TFE and the peptide. Copyright © 2001 John Wiley & Sons, Ltd.
Prostasome&hyphen;like particles are involved in the transfer of P25b from the bovine epididymal fluid to the sperm surface
Authors: Frenette Gilles , Sullivan Robert 
Published: August 2002

AbstractIn bulls, P25b is a sperm protein associated with the plasma membrane covering the acrosome. The amount of P25b bound to a constant number of spermatozoa varies from one individual to the other, low levels being associated with bull subfertility. In this study, we describe the epididymal origin of P25b using Western blot analysis. Whereas P25b was undetectable on caput spermatozoa, the amount of P25b associated to a constant number of spermatozoa increases from the corpus to the cauda. Prostasome&hyphen;like particles were prepared by ultracentrifugation of epididymal fluid. P25b appears to be also associated with those membranous vesicles in increasing amounts along the epididymis. P25b is anchored to the plasma membrane of spermatozoa through glycosylphosphatidyl&hyphen;inositol as shown by the ability of phospholipase C. but not of high salt treatment, to release P25b. Coincubation experiments revealed that prostasome&hyphen;like particles are able to transfer P25b to spermatozoa, this process being more efficient at slightly acidic pH. P25b thus appears to be a marker of sperm epididymal maturation in bulls. Mol. Reprod. Dev. 59:115&ndash;121, 2001. &copy; 2001 Wiley&hyphen;Liss, Inc.
Establishment and characterization of an immortalized human oviductal cell line
Authors: Lee Yin‐Lau , Lee Kai‐Fai , Xu Jia‐Sen , Wang Yan‐Ling , Tsao Sai‐Wah , Yeung William S.B. 
Published: August 2002

AbstractHuman oviductal cells stimulate embryo development in vitro partly by the production of embryotrophic glycoproteins. The identity of these glycoproteins is not yet known mainly because oviductal samples are limited and that the cultured parental oviductal cells cannot produce sufficient amount of embryotrophic factors for characterization. In this study, human oviductal epithelial cells (OE) were immortalized by HPV 16 E6/E7 open reading frame (ORF) by retroviral expression. The characteristics of this immortalized cell line (OE‐E6/E7) were compared to the parental OE. HPV 16 E6/E7 DNA was found only in OE‐E6/E7 but not in OE. Human oviduct‐specific glycoprotein, estrogen receptors, and cytokeratin were found in both cell types. Both OE and OE‐E6/E7 possessed telomerase activities but the former had much lower activity. OE‐E6/E7 also produced glycoproteins with chromatographic behavior similar to the embryotrophic glycoproteins derived from OE. These results showed that OE‐E6/E7 retained a number of characteristics of OE. The development of preimplantation mouse embryo was significantly better after coculture with OE‐E6/E7 when compared to medium alone culture in term of blastulation rates (52% vs. 32%) and blastocyst diameter (113.0 ± 2.07 μm vs. 83.9 ± 5.23 μm). This immortalized cell line can be used as a continuous and stable in vitro system for the study of the oviductal embryotrophic activity. Mol. Reprod. Dev. 59: 400–409, 2001. © 2001 Wiley‐Liss, Inc.
Sensitivity calculations and comparisons for shielded elliptical and circular birdcage coils
Authors: De Zanche Nicola , Allen Peter S. 
Published: August 2002

AbstractAn analytical framework is presented which justifies the use of a confocal elliptical shield (previously adopted on empirical or numerical grounds) to limit the spatial extent of the radiofrequency (RF) field produced by an elliptical birdcage coil, while concurrently minimizing field inhomogeneities. From this analytical capability it is further shown that the relative linear mode geometric sensitivities depend only on the shield dimensions and can be readily evaluated, thus providing an upper bound to the improvement in signal‐to‐noise ratio (SNR) of the damped elliptical birdcage over a circular coil of similar dimensions. The mismatch in the linear mode sensitivities can also be evaluated, and a method for the design of an appropriate feed configuration that ensures quadrature operation is given. Magn Reson Med 47:364–371, 2002. © 2002 Wiley‐Liss, Inc.
Coronary artery motion with the respiratory cycle during breath‐holding and free‐breathing: Implications for slice‐followed coronary artery imaging
Authors: Keegan Jennifer , Gatehouse Peter , Yang Guang‐Zhong , Firmin David 
Published: August 2002

AbstractThe displacement of the right coronary artery (RCA) origin with respiratory position was determined relative to the dome of the right hemidiaphragm in three orthogonal directions in eight healthy subjects. Both multiple breath‐hold and free‐breathing acquisitions were used, and motion correction factors for slice‐following applications were determined. The correction factors for all three directions showed considerable intersubject variability. The mean superior‐inferior factor was slightly less in free‐breathing than in breath‐holding (0.26 vs. 0.29, P = ns), and much less than the fixed value of 0.6 frequently implemented with slice‐following. The anterior‐posterior correction factors were uniformly low in free‐breathing, and significantly less than those obtained from breath‐holding (0.04 vs. 0.14, P < .05), while the mean left‐right correction factors were approximately 0.1 for both. It is concluded that subject variability in correction factors, together with within‐subject differences between breath‐holding and free‐breathing, is such that slice‐following should be performed with subject‐specific factors determined from free‐breathing acquisitions. Magn Reson Med 47:476–481, 2002. © 2002 Wiley‐Liss, Inc.
ADC characterization of region‐specific response to cerebral perfusion deficit in rats by MRI at 9.4 T
Authors: Yushmanov Victor E. , Wang Lei , Liachenko Serguei , Tang Pei , Xu Yan 
Published: August 2002

AbstractRegion‐specific cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) of water in the rat brain were quantified in vivo by high‐field MRI (9.4 T) for 6–7 h after middle cerebral artery occlusion (MCAO). Upon occlusion, average CBF fell from about 1.5–2 ml/g/min to below 0.5 ml/g/min in cortical areas and the amygdala, and below 0.2 ml/g/min in the caudate putamen. CBF in some of the homologous contralateral areas also decreased by 20–30%. Average ADC decreased from about 8 · 10−4 to 5 · 10−4 mm2/s in the caudate putamen and parietal cortex. Corresponding changes in ADC were lower in the frontal cortex and negligible in the piriform cortex, suggesting that the perfusion threshold for ADC decrease may be different for different brain regions in the same animal. The area of decreased ADC correlated well with the infarction area revealed by 2,3,5‐triphenyltetrazolium chloride (TTC) staining of brain slices in vitro. A better understanding of the mechanisms linking ADC and CBF changes to ischemic cell disorders may prove useful in characterizing the degree of tissue damage, and in developing and evaluating treatment strategies. Magn Reson Med 47:562–570, 2002. © 2002 Wiley‐Liss, Inc.
Representation of strong baseline contributions in 1H MR spectra
Authors: Soher Brian J. , Young Karl , Maudsley Andrew A. 
Published: August 2002

AbstractA comparison is made between two optimization procedures and two data models for automated analysis of in vivo proton MR spectra of brain, typical of that obtained using MR spectroscopic imaging at 1.5 Tesla. First, a shift invariant wavelet filter is presented that provides improved performance over a conventional wavelet filter method for characterizing smoothly varying baseline signals. Next, two spectral fitting methods are described: an iterative spectral analysis method that alternates between optimizing a parametric description of metabolite signals and nonparametric characterization of baseline contributions, and a single‐pass method that optimizes a complete spectral and baseline model. Both methods are evaluated using wavelet and spline models of the baseline function. Results are shown for Monte Carlo simulations of data representative of both long and short TE, in vivo 1H acquisitions. Magn Reson Med 45:966–972, 2001. © 2001 Wiley‐Liss, Inc.
Facioscapulohumeral muscular dystrophy with EcoRI/BlnI fragment size of more than 32 kb
Authors: Vielhaber Stefan , Jakubiczka Sibylle , Schröder J. Michael , Sailer Michael , Feistner Helmut , Heinze Hans‐Jochen , Wieacker Peter , Bettecken Thomas 
Published: August 2002

AbstractFacioscapulohumeral muscular dystrophy (FSHD) is associated with the deletion of a variable number of 3.3‐kb subunits of a tandemly arranged repeat (D4Z4) on chromosome 4q35. EcoRI/BlnI fragments in the range of 10–35 kb are currently defined as disease‐associated. Diagnosis of FSHD is frequently complicated by interchromosomal exchange with a homologous locus on 10q26. We present clinical and laboratory data of six subjects from two unrelated families with a marked FSHD phenotype and EcoRI/BlnI fragments of 39 and 33 kb, respectively. Origin on chromosome 4q35 was confirmed by haplotype analysis in the first family and was supported by pulsed field gel electrophoresis data in the second family. Our data further confirm the existence of a region of overlap of normal and pathological fragments. Fragments from this region can obviously be associated with marked FSHD phenotypes. Furthermore, application of linked markers and resolution of all EcoRI/BlnI fragments by pulsed field gel electrophoresis in addition to routine laboratory tests considerably augments the information obtained from molecular tests, upon which genetic counselling can then be based. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Pathophysiology of weakness in a patient with congenital end‐plate acetylcholinesterase deficiency
Authors: Kohara Nobuo , Lin Thy‐Sheng , Fukudome Takayasu , Kimura Jun , Sakamoto Takashi , Kaji Ryuji , Shibasaki Hiroshi 
Published: August 2002

AbstractA Japanese patient with congenital end‐plate acetylcholine esterase (AChE) deficiency developed severe proximal and truncal muscle weakness with preservation of distal strength. Electrophysiological studies included a train of stimuli at 3 HZ, which induced a marked decremental response in the deltoid but not in the first dorsal interosseous (FDI) muscle. Single fiber electromyography (EMG) revealed a high blocking rate (23.1 ± 30.5%, n = 13) with a markedly increased jitter (mean consectuve difference [MCD] 297 ± 218 μs) in the deltoid, but a low blocking rate (6.2 ± 7.4%, n = 16) despite an equally increased jitter (MCD 227 ± 147 μs) in the FDI. In vitro microelectrode study and computer simulation suggested that the combination of a large jitter and a low blocking rate may be ascribed to a reduced end‐plate potential (EPP) amplitude with an abnormally prolonged decay time constant (τ). These characteristics may constitute the primary underlying pathophysiologic mechanism in our patient and in similar cases of congenital myasthenic syndrome. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002