bluuebunny/crossref_metadata_2025 huggingface dataset:
Complexity theory and models for social networks
Authors: Skvoretz John
Published: January 2003

Much work in complexity theory employs agent‐based models in simulations of systems of multiple agents. Agent interaction follows some standard types of network topologies. My aim is to assess how recent advances in the statistical modeling of social networks may contribute to agent‐based modeling traditions, specifically, by providing structural characterizations of a variety of network topologies. I illustrate the points by reference to a computational model for the evolution of cooperation among agents embedded in neighborhoods and by reference to complex, real social networks defined by the ties of political support between US Senators as revealed through ties of cosponsorship of legislation. © 2003 Wiley Periodicals, Inc.
Gray‐scale and color Doppler findings in bilateral internal jugular vein thrombosis caused by anaplastic carcinoma of the thyroid
Authors: Panzironi Giuseppe , Rainaldi Roberto , Ricci Francesca , Casale Alessandra , Macciucca Marina De Vargas
Published: January 2003

Bilateral internal jugular vein thrombosis is a rare complication of thyroid cancer. The most common manifestation of this condition is superior vena cava syndrome. We report the sonographic findings in a case of bilateral internal jugular vein thrombosis with mild symptoms. There was evidence of direct infiltration of anaplastic thyroid carcinoma into the left internal jugular vein. Sonographic and CT examinations also demonstrated multiple dilated collateral veins. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:111–115, 2003
Imaging findings in Mondor's disease
Authors: Yanik Bahar , Conkbayir Işik , Öner Özgür , Hekimoğlu Baki
Published: January 2003

Mondor's disease, or acute thrombophlebitis of superficial veins of the breast, occurs rarely, and little information is available in the medical literature on imaging findings in this disease. We present the case of a 59‐year‐old woman who underwent evaluation of a palpable, painful cord in her left breast associated with discoloration of the overlying skin. Mammography revealed a 10‐cm‐long linear density in her left breast. Gray‐scale sonography showed a noncompressible, hypoechoic, undulating tubular structure in the subcutaneous fat. Color Doppler imaging revealed no flow signal in this structure, although we observed arterial flow signals adjacent to it. We diagnosed Mondor's disease and treated the patient symptomatically; 6‐week follow‐up examinations demonstrated resolution of the venous thrombosis. The use of sonography, particularly color Doppler imaging, can aid in diagnosing Mondor's disease and in monitoring its resolution. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:103–107, 2003
Infantile scrotal pyocele simulating missed testicular torsion on sonography
Authors: Lim Gye‐Yeon , Lim Soo‐Ah , Jeong Yeon‐Joo , Hahn Seong‐Tae , Lee Jae‐Mun
Published: January 2003

We present the case of a neonate with idiopathic infantile pyocele. Scrotal sonography revealed a complex fluid collection within the left scrotal sac containing septations and a fluid‐fluid level. The dependent region of the collection had moderate echogenicity, the slightly hypoechoic testis was not well defined, and the scrotal wall was thickened. Color Doppler sonography revealed mild hypervascularity in the thickened scrotal wall but no vascularity inside the testis. The sonographic findings suggested missed testicular torsion, but surgery revealed a pyocele, for which no source was identified. Radiologists should be aware that idiopathic infantile pyocele can mimic the Doppler sonographic findings in missed testicular torsion. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:116–118, 2003
Caput succedaneum mimicking a cephalocele
Authors: Gerscovich Eugenio O. , McGahan John P. , Jain Kiran A. , Gillen Marijo A.
Published: January 2003

Caput succedaneum is relatively common at birth but infrequently diagnosed in utero. It has a benign prognosis, but it is very important not to misdiagnose it as a cephalocele, which carries a guarded prognosis. We present the case of a patient who experienced preterm labor and premature rupture of the membranes at 28 weeks' menstrual age. Our initial diagnosis was cephalocele, but after the male infant was delivered by cesarean section, examination revealed no bone defect, and our final diagnosis was caput succedaneum. We also discuss the sonographic findings and diagnostic differences between caput succedaneum, cephalocele, and other fetal head masses. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:98–102, 2003
Correlation between prostate cancer grade and vascularity on color doppler imaging: Preliminary findings
Authors: Tang Jie , Li Song , Li Junlai , Luo Yukun , Xu Jianhong , Zhang Yan , Li Xin , Shi Huaiyin , Zhang Gaokui
Published: January 2003

Purpose

We examined the relationship between the amount of prostate cancer–associated vascularity as seen on color Doppler imaging and the tumor grade.

Methods

Transrectal color Doppler imaging of the prostate was performed in 54 patients with prostate cancer. Color flow signal/total pixel ratios (SPRs) of selected images were calculated using the ratio of the number of pixels showing color Doppler signals to the total number of pixels within the lesion. All the patients underwent prostate biopsy guided by transrectal sonography. Gleason scores were determined from the biopsy specimens.

Results

Color Doppler signals were demonstrated in the lesions of 91% (49/54) of the patients. The mean SPRs of prostate cancers 3 cm or smaller and larger than 3 cm were 0.15 ± 0.07 and 0.11 ± 0.04 (± standard deviation), respectively (p < 0.05). The mean SPRs of well‐ (Gleason score of 2–4), moderately (Gleason 5–7), and poorly (Gleason 8–10) differentiated prostate cancers were 0.08 ± 0.03, 0.12 ± 0.06, and 0.17 ± 0.11, respectively (r = 0.45; p < 0.01).

Conclusions

The refinement of color Doppler equipment has improved the detection of color Doppler signals associated with prostate cancer. Our study shows a correlation between prostate cancer–associated vascularity as shown on color Doppler imaging and the tumor grade. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:61–68, 2003
Chest sonography versus lateral decubitus radiography in the diagnosis of small pleural effusions
Authors: Kocijančič Igor , Vidmar Ksenija , Ivanovi‐Herceg Zlata
Published: January 2003

Purpose

The aim of this prospective study was to assess the value of chest sonography in the radiologic diagnosis of small pleural effusions (relative to expiratory lateral decubitus radiography) and to suggest gray‐scale sonographic criteria for detecting the presence of small pleural effusions.

Methods

Patients referred for abdominal or chest sonographic evaluation for various reasons were also examined for sonographic features of pleural effusion from May 1, 1997, until January 31, 2000. Patients who had evidence of small pleural effusions were included. Patients with no such evidence served as a control group. Subsequently, all patients underwent erect posteroanterior and expiratory lateral decubitus chest radiography.

Results

On chest sonography, 52 patients were found to have small pleural effusions. The control group consisted of 17 patients. The mean thickness of the pleural effusion was 9.2 mm on sonography and 7.6 mm on expiratory lateral decubitus radiography (p < 0.01). Compared with radiologic examination, chest sonography had a positive predictive value of 92% in the diagnosis of small pleural effusions in our study population.

Conclusions

Chest sonography showed a high degree of accuracy relative to that of lateral decubitus chest radiography in the diagnosis of small pleural effusions, which appeared as thin (usually 15 mm thick or less) anechoic areas that changed shape with the phases of respiration. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:69–74, 2003
Angiogenesis of the heart
Authors: Kutryk Michael J.B. , Stewart Duncan J.
Published: January 2003

Despite continued advances in the prevention and treatment of coronary artery disease, there are still a large number of patients who are not candidates for the conventional revascularization techniques of balloon angioplasty and stenting, or coronary artery bypass grafting (CABG). Therapeutic angiogenesis, in the form of the administration of growth factor protein or gene therapy, has emerged as a promising new method of treatment for patients with coronary artery disease. The goal of this strategy is to promote the development of supplemental blood conduits that will act as endogenous bypass vessels. New vessel formation occurs through the processes of angiogenesis, vasculogenesis, and arteriogenesis, under the control of growth factors such as those that belong to the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and angiopoeitin (Ang) families of molecules. Preclinical studies have suggested that such an approach is both feasible and effective; however many questions remain to be answered. This review will address the elements of pharmacologic revascularization, focusing on gene and protein‐based therapy. The important growth factors, the vector (for gene therapy), routes of delivery, the desired therapeutic effect, and quantifiable clinical end points for trials of angiogenesis will all be addressed. Microsc. Res. Tech. 60:138–158, 2003. © 2003 Wiley‐Liss, Inc.
Endothelial cell tumors
Authors: Bell Cecil David
Published: January 2003

Historically, there has been much debate on the nature of infantile hemangiomas as either congenital malformations or benign neoplasms. Some vascular lesions that are present at birth and evidence no proliferative growth are considered to be congenital malformations; other post‐natal vascular tumors pursue aggressive and possibly lethal clinical courses. The literature of the last two decades has been reviewed with a hope of clarifying the pathogenesis and underlying molecular lesions of this diverse set of lesions. Genetic investigations of two diseases associated with vascular tumors and abnormalities, von Hippel‐Lindau disease, and Hereditary Hemorrhagic Telangiectasia have greatly added to our knowledge of vascular proliferation and provided a tantalizing clue to the pathogenesis of hemangioblastomas. Mutations have also been described in infantile hemangiomas. All of the entities considered, vascular neoplasms as well as malformations, have been examined for the expression of vascular growth factors, their receptors, and factors that appear to promote cell proliferation. Similarly, factors that either block or promote apoptosis have also been examined in various vascular lesions. These studies have in large confirmed our expectations about proliferating tumors that show upregulation of growth promoting factors and inhibition of those that promote apoptosis. In conclusion, although much has been learned about vascular physiology and the control of endothelial proliferation, and while understanding about the molecular pathogenesis of the two inherited diseases mentioned above is detailed but not yet complete, understanding of the pathogenesis of benign and malignant endothelial tumors remains vague. Microsc. Res. Tech. 60:165–170, 2003. © 2003 Wiley‐Liss, Inc.
Tumor angiogenesis of non–small cell lung cancer
Authors: Shijubo Noriharu , Kojima Hiroshi , Nagata Manabu , Ohchi Takashi , Suzuki Akihiro , Abe Shosaku , Sato Noriyuki
Published: January 2003

Lung cancer is one of the commonest causes of cancer death in developed countries. Recent evidence suggests that angoigenesis is related to poor prognosis in many solid tumors including non–small cell lung cancer (NSCLC). Angiogenesis is regulated by a complex interaction among growth factors and cytokines and influenced by proteolytic enzymes such as plasminogen activators and matrix metalloproteases, expression of adhesion molecules, and distribution of extracellular matrices. Fibroblasts, macrophages, mast cells, and endothelial cells themselves also affect angiogenesis. This review concentrates on angiogenic growth factors including vascular endothelial growth factor, angiopoietins, platelet derived endothelial growth factor, and basic fibroblast growth factor, proteases, adhesion molecules including vascular endothelial cadherin and integrins, osteopontin, and mast cell products in tumor angiogenesis of NSCLC. Microsc. Res. Tech. 60:186–198, 2003. © 2003 Wiley‐Liss, Inc.
Biology of angiogenesis in tumors of the gastrointestinal tract
Authors: Reinmuth Niels , Parikh Alexander A. , Ahmad Syed A. , Liu Wenbiao , Stoeltzing Oliver , Fan Fan , Takeda Akihiko , Akagi Morihisa , Ellis Lee M.
Published: January 2003

The realization that the growth and spread of tumors are dependent on angiogenesis has created new avenues of research designed to help us to better understand cancer biology and to facilitate the development of new therapeutic strategies. However, the process of angiogenesis consists of multiple, sequential, and interdependent steps with a myriad of positive and negative regulators of angiogenesis being involved. The survival of tumors and thus their metastases are dependent upon the balance of endogenous angiogenic and anti‐angiogenic factors such that the outcome favors increased angiogenesis. Several growth factors have been identified that regulate angiogenesis in cancers of the gastrointestinal tract. These include pro‐angiogenic factors like vascular endothelial growth factor (VEGF) and anti‐angiogenic factors, i.e., thrombospondin. The following review provides a brief overview about the most important factors that are involved in the angiogenic process in tumors derived from colon, stomach, and pancreas. A thorough understanding of the role these factors play in the angiogenic process may lead to the development of novel therapeutic antineoplastic strategies. Microsc. Res. Tech. 60:199–207, 2003. © 2003 Wiley‐Liss, Inc.
Angiogenesis in brain tumors
Authors: Lopes M. Beatriz S.
Published: January 2003

Angiogenesis is a complex process regulated by multiple stimulatory and inhibitory factors that are able to modulate the migration and/or proliferation of microvascular cells with the objective of formation of neovasculature from preexisting vessels. It involves well‐coordinated steps including production and release of angiogenic factors, proteolytic degradation of extracellular matrix components to allow formation of capillary sprout, proliferation and directional migration of microvascular cells, and the final composition of new vessels [Senger (1996) Am. J. Pathol. 149:1–7]. Angiogenesis is present in a number of hypoxic and/or ischemic conditions in the central nervous system, in particular in infarctions and infectious processes. Angiogenesis also plays an important role in malignant primary tumors. Glioblastomas, the most malignant gliomas in adults, are among the most angiogenic of all human tumors. This review will examine recent data of the role of angiogenic growth factors in the neoplastic and reactive conditions in the brain. Microsc. Res. Tech. 60:225–230, 2003. © 2003 Wiley‐Liss, Inc.
Architectonics of crayfish ganglia
Authors: Mulloney Brian , Tschuluun Naranzogt , Hall Wendy M.
Published: January 2003

The central nervous system of crayfish consists of a chain of segmental ganglia that are linked by cables of intersegmental axons. Each ganglion contains a highly‐ordered core of longitudinal tracts, vertical tracts, commissures, and synaptic neuropils. We review from a technical perspective the history of the description of these ganglia, and recognize four episodes of progress. Each major innovation in anatomical methods has led to new insight into the structure and function of this nervous system, and new awareness of the structural patterns that are common to the CNS of all arthropods. Ganglia in different segments of the body differ in size, and appear to differ in anatomy. From a comparison of the structures of the cores of abdominal, thoracic, and subesophageal ganglia, we argue that this apparent difference is illusory. Rather, each of these ganglia is organized on the same plan, a plan also found in insect segmental ganglia. The apparent differences follow from longitudinal compression during development and from allometric growth of particular neuropils associated with innervation of the walking legs. Different authors have described the internal organization of ganglia in different segments, so we provide a cross‐reference to the nomenclatures they have introduced. We compare the locations of cell bodies of motor neurons and accessory neurons that innervate different peripheral structures, and demonstrate double‐labeling of certain GABAergic peripheral inhibitory neurons. Finally, we describe the construction of digital movies of serial sections of these ganglia, and discuss their utility. Microsc. Res. Tech. 60:253–265, 2003. © 2003 Wiley‐Liss, Inc.
The effects of serotonin and ecdysone on primary sensory neurons in crayfish
Authors: Cooper Robin L. , Ward Elizabeth , Braxton Recennah , Li Hao , Warren Wendy M.
Published: January 2003

The overall behaviors and motivational states observed during social interactions and throughout the molting cycle of crayfish have been linked to the effects of humoral neuromodulators. Both serotonin (5‐HT) and a molt‐related hormone, 20‐hydroxyecdysone (20‐HE), are known to be present in the hemolymph of crustaceans. To determine if they alter the activity of a primary sensory neuron that monitors proprioceptive information, we examined their effects on the activity of the slow‐adapting muscle receptor organ (MRO) of the crayfish abdomen, a model sensory system that has been extensively studied. 5‐HT within the range of 100 nM to 1 μM, increases the firing frequency of the neuron during sustained stimulation. In experiments in which 20‐HE was added alone, an increase in the firing frequency also occurred, although to a lesser degree than that for 5‐HT at the same concentrations. When the MRO is first exposed to 20‐HE, followed sequentially by 5‐HT, the activity increases to about the same degree as in the reverse order of exposure. This outcome indicates that mixtures of these endogenous neuromodulators, at various levels, are more important in alternating behavior than the absolute level of any one of them introduced alone. Microsc. Res. Tech. 60:336–345, 2003. © 2003 Wiley‐Liss, Inc.
Amine neurochemistry and aggression in crayfish
Authors: Panksepp Jules B. , Yue Zhaoxia , Drerup Catherine , Huber Robert
Published: January 2003

A primary goal of our research is to explore proximate mechanisms important in recruiting adaptive social behaviors. For instance, if one of three different behaviors may be expressed in a particular set of circumstances, how do neurochemical mechanisms bias behavior towards the expression of one act in lieu of the other possibilities? In this article, we review recent results suggesting that serotonin may play such a role in the control of aggression in crayfish. First, we summarize techniques that have been optimized for sensitive characterization of neurochemical profiles in crayfish. Then, borrowing concepts from behavioral ecology, we review a framework for quantitative investigation, which regards behavior as a set of individual decisions, each with a particular probability for occurrence, a motivational context, and controlled by its own distinct neurochemical mechanisms. Microsc. Res. Tech. 60:360–368, 2003. © 2003 Wiley‐Liss, Inc.
Uptake by mouse liver and intracellular fate of plasmid DNA after a rapid tail vein injection of a small or a large volume
Authors: Lecocq Michèle , Andrianaivo Fanjam , Warnier Marie‐Thérèse , Wattiaux‐De Coninck Simone , Wattiaux Robert , Jadot Michel
Published: January 2003

Background

An efficient gene transfer can be achieved in mouse liver by a rapid tail vein injection of a large volume of plasmid DNA solution (hydrodynamics‐based transfection). The mechanism of gene transfer by this procedure is not known. It must be related to the uptake and intracellular fate of DNA.

Methods

We have investigated the problem by following the uptake by mouse liver and the intracellular distribution of DNA after a rapid tail vein injection of a large (2.0 ml) or a small (0.2 ml) volume of 35S‐DNA solution. Total and acid‐soluble radioactivity were measured in liver homogenates at increasing times after injection, and their subcellular distributions were established by centrifugation methods and compared with the distributions of marker enzymes of the membrane compartments involved in endocytosis: alkaline phosphodiesterase (plasma membrane) and cathepsin C (lysosomes).

Results

35S‐DNA uptake by the liver is similar when a small or a large volume of injection is used but its degradation is markedly slower after a 2.0 ml injection. When a small volume of injection is given, distribution of radioactivity after differential centrifugation indicates that the plasmid DNA is endocytosed and reaches lysosomes where it is hydrolysed. After a large volume injection, part of 35S‐DNA has the same fate, another part remains acid‐precipitable for at least 1 h and is associated with structures sedimenting at low centrifugation speed in the nuclear fraction N. Analysis of that fraction by gradient centrifugation suggests that these structures are plasma membrane fragments that could originate from the apical domain of hepatocytes. The proportion of 35S‐DNA associated with hepatocytes is about doubled after a large volume injection. Fractionation of isolated hepatocytes by centrifugation confirms results obtained on the whole liver. Treatment of the N fraction or isolated hepatocytes with pancreatic DNAse illustrates that 35S‐DNA that remains bound to plasma membrane after a large volume injection is located on the outer face.

Conclusions

The fact that after an hydrodynamic injection 35S‐DNA remains bound to the outside face of the plasma membrane for at least 1 h indicates that it is not, or very slowly, internalised during that period. The relatively small difference in the amount of DNA picked up by hepatocytes depending on the type of injection could not explain the absence of expression after a conventional injection and the strong expression after a hydrodynamic injection. If DNA enters the cells by endocytosis, even after an hydrodynamic injection, its persistence at the outside face of the plasma membrane could favour transfection by allowing hepatocytes to dispose for a relatively long time of a reservoir of intact DNA. Copyright © 2002 John Wiley & Sons, Ltd.
Marked enhancement in gene expression by targeting the human insulin receptor
Authors: Zhang Yun , Boado Ruben J. , Pardridge William M.
Published: January 2003

Background

Exogenous genes can be delivered to cells without viral vectors using an “artificial virus” comprised of nonviral plasmid DNA encapsulated in the interior of 85 nm pegylated immunoliposomes (PIL). The liposomes are targeted to cells with receptor‐specific targeting ligands such as receptor‐specific peptidomimetic monoclonal antibodies.

Methods

The levels of luciferase gene expression in human or rat glioma cells are measured after targeting the PIL‐encapsulated plasmid DNA via the human insulin receptor, the human epidermal growth factor receptor, or the rat transferrin receptor. The luciferase expression plasmids were either derived from pCEP4, which contains the Epstein‐Barr nuclear antigen‐1/oriP replication system, or from pGL2, which lacks this system for episomal replication of plasmid DNA.

Results

Depending on the plasmid construct used and the receptor targeted, the peak luciferase gene expression varied more than 200‐fold from 1.8 ± 0.1 to 419 ± 31 pg luciferase per mg cell protein. With the same plasmid, the peak level of gene expression following delivery to the cell via the human insulin receptor was 100–200‐fold higher than gene expression following delivery via either the epidermal growth factor receptor or the transferrin receptor. There was no gene expression if the targeting ligand on the PIL was replaced with a nonspecific isotype control antibody.

Conclusions

The extent to which an exogenous gene is expressed within a cell via a nonviral, receptor‐mediated gene transfer technology is determined by the receptor specificity of the targeting ligand. The highest levels of gene expression are obtained after targeting the insulin receptor, and this may derive from the nuclear targeting properties of this receptor system. Copyright © 2002 John Wiley & Sons, Ltd.
Gene therapy and tissue engineering for sports medicine
Authors: Huard Johnny , Li Yong , Peng Hairong , Fu Freddie H.
Published: January 2003

Sports injuries usually involve tissues that display a limited capacity for healing. The treatment of sports injuries has improved over the past 10 to 20 years through sophisticated rehabilitation programs, novel operative techniques, and advances in the field of biomechanical research. Despite this considerable progress, no optimal solution has been found for treatment of various sports‐related injuries, including muscle injuries, ligament and tendon ruptures, central meniscal tears, cartilage lesions, and delayed bone fracture healing. New biological approaches focus on the treatment of these injuries with growth factors to stimulate and hasten the healing process. Gene therapy using the transfer of defined genes encoding therapeutic proteins represents a promising way to efficiently deliver suitable growth factors into the injured tissue. Tissue engineering, which may eventually be combined with gene therapy, may potentially result in the creation of tissues or scaffolds for regeneration of tissue defects following trauma. In this article we will discuss why gene therapy and tissue engineering are becoming increasingly important in modern orthopaedic sports medicine practice. We then will review recent research achievements in the area of gene therapy and tissue engineering for sports‐related injuries, and highlight the potential clinical applications of this technology in the treatment of patients with musculoskeletal problems following sports‐related injuries. Copyright © 2002 John Wiley & Sons, Ltd.
Chronic thalamic stimulation in a patient with spinocerebellar ataxia type 2
Authors: Pirker Walter , Back Claude , Gerschlager Willibald , Laccone Franco , Alesch Francois
Published: January 2003

We report on a patient with spinocerebellar ataxia type 2 (SCA 2) with an unusual clinical presentation, including severe, disabling resting and action tremor and the successful treatment of this tremor syndrome with chronic thalamic stimulation. Using [123I]β‐CIT single photon emission computed tomography, we document a marked degeneration of the nigrostriatal dopaminergic system in SCA 2. © 2002 Movement Disorder Society
Deficit of verb generation in nondemented patients with Parkinson's disease
Authors: Péran Patrice , Rascol Olivier , Démonet Jean‐François , Celsis Pierre , Nespoulous Jean‐Luc , Dubois Bruno , Cardebat Dominique
Published: January 2003

Clinical and neuroimaging studies have shown that verb processing suggests a preferential participation of a prefrontal network, which is dysfunctional in Parkinson's disease (PD). To assess a verb processing deficit in PD, we compared noun‐ and verb‐generation tasks for 34 nondemented PD patients (according to the Dementia Rating Scale) with 34 matched normal subjects, using two intracategory tasks (noun/noun and verb/verb generation) and two intercategory tasks (noun/verb and verb/noun generation). PD patients were significantly impaired in the two tasks involving verb production, i.e., verb/verb and noun/verb generation, whereas their performance was similar to those of controls in the two tasks requiring noun production. For the two impaired tasks, we assessed 1) the influence of lexical competition that corresponds to the presence of several candidate words for a given stimulus; 2) the influence of slight cognitive dysfunction; and 3) the influence of motor deficit. Significant correlations were found between DRS scores and performance on the noun/verb task, and no significant correlations were found between lexical competition or motor deficit and performance. The specific deficit for verb production in PD patients is discussed in relation to deficits affecting either action or grammatical representations. © 2002 Movement Disorder Society
Acute effect of transcutaneous electrical nerve stimulation on tremor
Authors: Munhoz Renato P. , Hanajima Ritsuko , Ashby Peter , Lang Anthony E.
Published: January 2003

Based on the claims that transcutaneous electrical nerve stimulation is effective in myoclonic dystonia and essential tremor, we evaluated its acute effects in 5 patients with essential tremor and 2 patients with tremor attributed to peripheral neuropathy using as parameters the Washington Heights‐Inwood Genetic Study of Essential Tremor rating scale, self‐reported impression, and recording of electromyographic activity. We found no significant improvement in any of the parameters tested. © 2002 Movement Disorder Society
Effects of CB1 cannabinoid receptor modulating compounds on the hyperkinesia induced by high‐dose levodopa in the reserpine‐treated rat model of Parkinson's disease
Authors: Segovia Gregorio , Mora Francisco , Crossman Alan R. , Brotchie Jonathan M.
Published: January 2003

The present study was designed to determine the potential of CB1 cannabinoid receptor modulating compounds in the treatment of L‐3,4‐dihydroxyphenylalanine (L‐dopa)–induced dyskinesia in Parkinson's disease. In the reserpine‐treated rat model of parkinsonism, administration of a high dose of L‐dopa (150 mg/kg) but not of Cl‐APB (0.5 mg/kg) or quinpirole (0.5 mg/kg) produced a hyperkinetic state characterised by an increase in horizontal and vertical activity, which likely represent correlates of antiparkinsonian and dyskinetic activity, respectively. Injection of the CB1 cannabinoid receptor antagonist SR141716 (0.1–3 mg/kg) reduced the increase in vertical activity elicited by L‐dopa without affecting the increase in horizontal activity. Injection of the CB1 cannabinoid receptor agonist WIN55,212‐2 (0.1–3 mg/kg) reduced the L‐dopa–induced increase in vertical activity and, at the highest dose only (3 mg/kg), also reduced horizontal activity elicited by L‐dopa. WIN55,212‐2 (1 mg/kg) reduced motor activity induced by both the D1 receptor agonist Cl‐APB (0.5 mg/kg) and the D2 receptor agonist quinpirole (0.5 mg/kg) in the reserpine‐treated rat. SR141716 (1 mg/kg) had no effects on motor activity induced by Cl‐APB (0.5 mg/kg) nor quinpirole (0.5 mg/kg) in the reserpine‐treated rat. Injection of the inhibitor of endocannabinoid transport AM404 (0.1–1 mg/kg) did not affect the increase in horizontal or vertical activity elicited by L‐dopa (150 mg/kg) in the reserpine‐treated rat. The data suggest that both CB1 cannabinoid receptor antagonists and agonists can modulate the behavioural effects of L‐dopa and may be useful for the treatment of the dyskinesia associated with long‐term L‐dopa treatment of Parkinson's disease. © 2002 Movement Disorder Society
Double‐blind, single‐dose, cross‐over study of the effects of pramipexole, pergolide, and placebo on rest tremor and UPDRS part III in Parkinson's disease
Authors: Navan Prithiva , Findley Leslie J. , Jeffs Jim A. R. , Pearce Ronald K. B. , Bain Peter G.
Published: January 2003

Tremor is one of the cardinal signs of Parkinson's disease (PD) but its response to antiparkinsonian medication is variable. It has been postulated that pramipexole may have a stronger antiparkinsonian tremor effect than pergolide, another direct acting dopamine agonist medication, possibly because the former has preferential affinity for the dopamine D3 receptor. The purpose of this pilot study was to compare the effects of a single oral dose of either pramipexole (Pr) or pergolide (Pe) or placebo (Pl) on parkinsonian tremor and the motor (part III) subsection of the UPDRS. Ten patients (6 men, 4 women), mean age 65.3 years, mean duration from diagnosis of 2.6 years, with tremor dominant PD were recruited. On three separate occasions a single dose of pramipexole (salt) 500 μg, pergolide 500 μg or placebo were administered in random order to each patient, who were pretreated with domperidone and had their antiparkinsonian medication withheld from midnight before study. After each medication patients were assessed at baseline and then every 30 min for 4 hr using a 0 to 10 tremor rating scale and the UPDRS (part III) in a double‐blind protocol. Adverse effects were systematically recorded. The results demonstrate that 500 μg of either pramipexole or pergolide reduced PD rest tremor scores to a similar degree, which at peak effect was significantly greater than placebo (respectively Pe v Pl: P < 0.006, Pr v Pl: P < 0.033). The two active drugs also had weaker beneficial effects on the UPDRS part III. Pergolide, however, was significantly more likely than pramipexole to cause nausea (P = 0.005) or vomiting (P = 0.014). © 2002 Movement Disorder Society
Impact of social functioning and vitality on preference for life in patients with Parkinson's disease
Authors: Morimoto Takeshi , Shimbo Takuro , Orav John E. , Matsui Kunihiko , Goto Masashi , Takemura Manabu , Hira Kenji , Fukui Tsuguya
Published: January 2003

The determinants of preference for life in patients with Parkinson's disease are not well known. We assessed the effect of functional status on the preference for life as measured by the time trade‐off method with a 10‐year life span. Our survey was based on a random sample of 1,200 patients from the Japanese Association of Patients with Parkinson's Disease. Patients' demographics, clinical information, and functional status as measured by the MOS Short Form 36 were considered independent variables. The response rate was 63.5%. Linear regression showed that men had a significantly stronger preference for current health than women (by 10.4 months on a scale of 10 years). Patients with higher physical functioning, social functioning, and vitality had significantly higher preferences for life (each 10‐point improvement in physical or social functioning led to a 1.5‐month increment in preference for current health; a 10‐point improvement in vitality led to a 3‐month increment). Longer duration of disease and advanced Hoehn and Yahr stage were significantly associated with a lower preference for current health (by 0.5 months/year of disease and by 2.6 months/stage). Interventions that target social functioning and vitality may be beneficial to preference for life. © 2002 Movement Disorder Society
S18Y polymorphism in the UCH‐L1 gene and Parkinson's disease: Evidence for an age‐dependent relationship
Authors: Elbaz Alexis , Levecque Clotilde , Clavel Jacqueline , Vidal Jean‐Sébastien , Richard Florence , Corrèze Jean‐René , Delemotte Bernard , Amouyel Philippe , Alpérovitch Annick , Chartier‐Harlin Marie‐Christine , Tzourio Christophe
Published: January 2003

We studied the relationship between Parkinson's disease (PD) and the S18Y polymorphism in the UCH‐L1 gene and the effect on this relationship of age at onset, smoking, and pesticides. Patients requested free health coverage for PD to the Mutualité Sociale Agricole (MSA), the French health insurance organization for people whose work is related to agriculture. Controls requested reimbursement of health expenses to the MSA. A maximum of three controls were matched to each case. Analyses included participants with both parents born in Europe. There were no differences in S18Y genotypes between patients (n = 209; 67% SS, 32% SY, 1% YY) and controls (n = 488; 66% SS, 30% SY, 4% YY). The relationship between PD and S18Y was modified by age at onset (P = 0.03). The Y allele was inversely associated with PD for patients with onset before 61 years (odds ratio [OR] = 0.53; 95% confidence interval [CI], 0.29–0.99); there was no association for older patients (62–68 years: OR = 1.21; 95% CI, 0.67–2.20; >68 years: OR = 1.24; 95% CI, 0.67–2.31). Among patients, Y carriers had a later onset than noncarriers (P = 0.04). These findings were not modified or confounded by smoking and pesticides. In this community‐based case‐control study, carriers of the Y allele were at decreased risk of developing PD at a young age, independently of pesticides and smoking. © 2002 Movement Disorder Society
Bandstop characteristics of a triangular microstrip slotted patch as an electromagnetic bandgap (EBG)
Authors: Karpuz Ceyhun
Published: January 2003

A novel electromagnetic bandgap (EBG) circuit with a single cell, using a microstrip isosceles triangular patch inserted to the microstrip line, with wideband tuning capability is successfully demonstrated. Both measured and simulated results confirm that the stopband characteristics can easily be controlled by the slot dimensions. Moreover, the proposed EBG structure is simple and compact for MMIC applications. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 149–150, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10704
Gain improvement in L‐band EDFA using unpumped EDF in a double pass system
Authors: Harun S. W. , Tamchek N. , Poopalan P. , Ahmad H.
Published: January 2003

A new gain improvement technique for L‐band EDFA is presented. It uses an unpumped EDF in a double‐pass configuration in order to effectively suppress and completely exploit the backward ASE. Compared to a conventional single‐pass amplifier, the gain coefficient can be improved from 1.5 dB/mW to 3.1 dB/mW without much noise figure penalty. The L‐band EDFA can also reduce the pump power necessary to achieve a specified gain by about half, however, this occurs at the cost of noise figure increasing by 1.6 dB. The optimum length for an unpumped EDF is experimentally measured to be 3 m for both single‐pass and double‐pass systems. The maximum gain improvement of 15.5 dB was observed at a signal wavelength of 1572 nm while signal and pump powers were fixed at −30 dBm and 103 mW, respectively. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 154–156, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10706
Finite‐difference time‐domain simulation of resonant modes of rectangular dielectric resonators
Authors: Semouchkina Elena , Semouchkin George , Mittra Raj , Cao Wenwu
Published: January 2003

In this paper we employ finite‐difference time‐domain (FDTD) simulations to study the resonant modes in rectangular dielectric resonators (DRs). Three‐dimensional field patterns for these modes are derived, and the modes are represented by combinations of equivalent electric and magnetic dipoles. The possibility of exciting TM‐type modes in rectangular DRs is demonstrated. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 160–164, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10708
L‐band 360° broad‐bandwidth monolithic analog phase shifter
Authors: Liu K. , Pun E. Y. B. , Tian X. J.
Published: January 2003

An L‐band 360° broad‐bandwidth analog phase shifter is designed using varactor. New design equations for expanding bandwidth and improving linear phase‐shift are derived and applied to performances optimization in one circuit. The analog phase shifter is fabricated using MIC and SMT technologies. At 1.2 ∼ 2.0 GHz (L‐band), total phase‐shift of 360° and linear deviation of less than ±2.5% were obtained, and the insertion loss varied less than 2 dB across the band. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 164–166, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10709
A highly integrable, compact, reliable, and low‐WDL fiber‐optic tap coupler
Authors: Yin Shizhuo , Purwarsumarto Purwadi , Su Wei Hong , Luo Claire
Published: January 2003

In this paper, a highly integrable, compact, reliable, and low wavelength dependent loss (WDL) fiber‐optic tap coupler is presented. The coupler includes a single‐fiber collimator at the input end, a grating beam deflector, a housing, and a specially designed dual‐fiber collimator at the output end. One fiber of the dual‐fiber collimator serves as the output channel and the other fiber serves as the tap channel. To minimize WDL induced by the wavelength‐dependent diffraction efficiency of the phase grating, this dual‐fiber collimator is carefully designed so that wavelength‐dependent diffraction efficiency is largely compensated by the wavelength‐dependent coupling efficiency of the dual‐fiber collimator. A low WDL as small as 0.05 dB is achieved within the whole c‐band region. The tap ratio can also be adjusted by controlling the modulation depth of the diffraction grating. Since this unique coupler can be easily integrated with other fiber‐optic elements, such as variable optic attenuators (VOAs), it can be used to build a variety of fiber‐optic modulates with integrated power monitoring capability. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 166–170, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10710
Approach to a printed quadrifilar helical antenna meshing with the FDTD method
Authors: Letestu Y. , Guiffaut C. , Sharaiha A.
Published: January 2003

In this paper, an analysis of printed quadrifilar helical antennas (PQHAs) using the FDTD method is presented. We develop an in‐house software taking into account the dielectric substrate. A tape form meshing is used in modeling the PQHA strip. A good agreement observed between theory and experimental results proves the validity of the method used by the in‐house code for the PQHAs. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 172–175, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10712
Non‐autonomous chaotic analysis of the colpitts oscillator with Lur'e systems
Authors: Liu Ji‐Chyun , Chou Hsi‐Chiang , Liao Ming Chou , Ho Yi Shun
Published: January 2003

This paper presents a non‐autonomous chaotic analysis of the Colpitts oscillator. It is available for injection‐locked and synchronized designs of communication systems. The injected BJT Colpitts oscillator, constructed with Lur'e systems, is simulated and measured in applications. Using the Runge–Kutta algorithm, the phase portrait, time response, and power spectrum are represented with a series of simulation results. The dynamic maps of locking, transition, and normal areas are depicted by measurements of the related frequencies and output powers. Both simulation and measurement identify the amplitudes and frequencies of the injected sinusoidal wave, which affect the chaos in the Colpitts oscillator. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 175–181, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10713
A flexible continuous beamformer with time delay for an optical‐controlled phased‐array antenna
Authors: Yang Jianliang , Tjin Swee Chuan , Liu Yunqi , Ngo Nam Quoc
Published: January 2003

A flexible continuous optical beamformer with time delay for a phased‐array antenna is proposed and demonstrated. It is constructed using a novel tunable chirped fiber grating achieved by bending a uniform grating, and a multi‐wavelength fiber laser based on a novel Sagnac interferemetric filter that consists of a polarization‐maintaining directional coupler and polarization‐maintaining fibers. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 187–190, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10716
Synthesis of a hybrid NLTL frequency doubler: Effects of diodes' parasitic elements
Authors: Duraz E. , Duchamp J. M. , Ferrari P. , Tao J. W.
Published: January 2003

We give some conception rules to design hybrid‐frequency multipliers based on nonlinear transmission lines (NLTLs). The parasitic diodes' impact on the NLTL dispersive behavior and hence on the bandwidth position and conversion efficiency is pointed out. An 18‐section NLTL, designed with GaAs Schottky diodes for a 16–32 GHz frequency doubler, provides 31% conversion efficiency with 19‐dBm output power. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 190–193, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10717
Theoretical analysis of the anomalous dips of scattering parameter S22 in deep sub‐micrometer MOSFETs
Authors: Lin Yo‐Sheng , Lu Shey‐Shi
Published: January 2003

In this paper, a theory based on dual‐feedback circuit methodology is adopted to explain the anomalous dips of scattering parameter S22 in deep sub‐micrometer MOSFETs. It is found that the output impedance intrinsically behaves as a series RC circuit (for low substrate resistance) or a “shifted” series RC circuit (for very high substrate resistance) at low frequencies, and a parallel RC circuit at high frequencies. This inherent triple characteristic of the output impedance can cause two types of anomalous dips of S22 in a Smith chart. In this way, the two experimental results [1, 2], that is, the anomalous dips caused by high substrate resistance and high trans‐conductance (or wide gate‐width), can be explained simultaneously for the first time. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 193–200, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10718
Temperature compensation for a fiber‐Bragg‐grating‐based magnetostrictive sensor
Authors: Yi B. , Chu B. C. B. , Chiang K. S.
Published: January 2003

We demonstrate two simple techniques for the compensation of the temperature effects in a fiber‐Bragg‐grating‐based magnetostrictive sensor. These techniques are based on using two specially mounted fiber Bragg gratings (FBGs). In one technique, the two FBGs, perpendicular to each other, are bonded onto a single magnetostrictive plate, while in the other technique, they are bonded onto two different magnetostrictive bars that possess close thermal expansion coefficients and magnetostrictive coefficients of opposite signs. In both cases, the Bragg wavelength difference between the two FBGs is insensitive to the temperature and measures the sum of the magnetostrictive effects experienced by the two gratings. Using these techniques, we have been able to reduce the temperature sensitivity of the sensor by more than 10 times. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 211–213, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10722
Analytic analysis of a C‐shaped microshield broadside‐coupled coplanar waveguide with buried ground strip
Authors: Gong Xinbao , Yao Ji , Zhou Xilang
Published: January 2003

A conformal mapping method and partial capacitance techniques are used to derive simple and accurate closed‐form expressions of odd‐ and even‐mode capacitances and characteristic impedances for a C‐shaped microshield broadside‐coupled coplanar waveguide (CMBCCPW) with buried ground strip. Numerical results are compared to those provided by other authors. Good agreement is obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 214–216, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10723
Concept of a compact dual‐band dual‐port microstrip base station antenna for mobile communication systems
Authors: Gadzina A. , Słobodzian P.
Published: January 2003

This paper presents a concept of a dual‐band dual‐port microstrip base station antenna for mobile telecommunication systems. The main part of the paper describes considerations on the antenna array configuration as well as antenna pattern synthesis. As an application example, a model of a dual‐band dual‐port microstrip antenna for GSM900 and GSM1800 systems, along with measured data, are described. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 218–221, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10725