bluuebunny/crossref_metadata_2025 huggingface dataset:
Prospective study of phobic anxiety and risk of Parkinson's disease
Authors: Weisskopf Marc G. , Chen Honglei , Schwarzschild Michael A. , Kawachi Ichiro , Ascherio Alberto
Published: May 2003

Anxiety disorders are common in Parkinson's disease (PD). However, the risk of PD among people with anxiety has not been examined in a prospective cohort study. We examined this relation prospectively within the Health Professionals Follow‐Up Study, a cohort of US male health professionals. In 1988, anxiety was assessed using the Crown–Crisp phobic anxiety index in 35,815 men without PD, stroke, or cancer at baseline. There were 189 incident cases of PD during 12 years of follow‐up. After adjusting for age, smoking, and caffeine intake, the relative risk of PD among men with the highest level of anxiety (Crown–Crisp index scores of 4 and above) was 1.5 (95% CI = 1.0–2.1;P‐trend = 0.01) compared to men with the lowest level of anxiety. This positive association persisted after excluding cases of PD with onset in the first 2 years of follow‐up. Use of anxiolytic medication was also associated with an elevated risk of PD (RR= 1.6; 95% CI = 0.9–3.1), but adjusting for this potential confounder did not materially affect the association between anxiety and risk of PD. Our results suggest that anxiety is a risk factor for PD. Whether this association is causal or the result of shared underlying biology remains a question. © 2003 Movement Disorder Society
Flumazenil, a GABA antagonist, may improve features of Parkinson's disease
Authors: Ondo William G. , Hunter Christine
Published: May 2003

Manipulation of γ‐aminobutyrate (GABA) system has been little studied in Parkinson's disease, despite the fact that GABA subserves a large part of the basal ganglia, including the outflow tracts. To test whether antagonism of GABA could improve features of PD, we administered open label intravenous flumazenil to eight practically defined off patients and assessed UPDRS scores, bilateral 1‐minute hand‐tapping speed, and timed gait tests. Patients demonstrated significantly greater tapping speed, which peaked 40 minutes after injection (P < 0.05). Total motor Unified Parkinson's Disease Rating Scale scores modestly improved (P < 0.05). There were no adverse events. Mechanisms by which flumazenil could improve PD are discussed. © 2003 Movement Disorder Society
Tetrabenazine in the treatment of severe pediatric chorea
Authors: Chatterjee Anjan , Frucht Steven J.
Published: May 2003

Tetrabenazine (TBZ) is widely used to treat adults with hyperkinetic movement disorders; however, published experience with the drug in pediatric patients is limited. We report on 5 children with severe chorea who were treated with TBZ. TBZ effectively controlled chorea in 4 patients, and despite the need for relatively high doses, it was well tolerated. © 2003 Movement Disorder Society
Spasmodic dysphonia in a patient with the A to G transition at nucleotide 8344 in mitochondrial DNA
Authors: Peng Ying , Crumley Roger , Ringman John M.
Published: May 2003

Dystonia has been described in various diseases affecting mitochondrial function but spasmodic dysphonia, a form of focal dystonia, has not. We present a patient with action myoclonus affecting the hands and arms who carried the most common mutation in mitochondrial DNA causing the myoclonic epilepsy and ragged red fibers (MERRF) syndrome (the A→G substitution at nucleotide 8344 in the tRNALys gene). This patient also had spasmodic dysphonia that was responsive to treatment with intralaryngeal botulinum toxin. © 2003 Movement Disorder Society
Sleepiness in Parkinson's disease: A controlled study
Authors: Brodsky Matthew A. , Godbold James , Roth Tom , Olanow C. Warren
Published: May 2003

Sudden‐onset sleep episodes while driving have been reported in Parkinson's disease (PD) patients, and termed sleep attacks because they were reported to be irresistible and to occur without warning. We postulate that these episodes are due to excessive daytime sleepiness secondary to the high frequency of sleep disorders in PD patients and the sedative effects of dopaminergic medications. We assessed the frequency and relationship between excess daytime sleepiness and sleep episodes while driving (SE) in patients with PD. We evaluated 101 consecutive PD patients presenting to the Movement Disorder Center at the Mount Sinai School of Medicine using a questionnaire that incorporated a subjective estimate of sleepiness, the Epworth Sleepiness Scale (ESS) and information on disease severity and dopaminergic medications. One hundred age‐matched respondents without PD served as a control population. Excess daytime sleepiness was reported in 76% of PD patients compared to 47% of controls (P < 0.05). The mean ESS scores for PD patients was 9.1 ± 6.1 versus 5.7 ± 4.4 in controls (P < 0.001). ESS scores ≥10 were observed in 40.6% of PD patients compared to 19% of controls (P < 0.01) and 24% of PD patients had scores ≥15, compared to 5% of controls (P < 0.001). Sleep episodes while driving were experienced by 20.8% of PD drivers compared to 6% of control drivers (P < 0.05). The mean daily levodopa (L‐dopa) dose equivalent was 1,142 ± 858 mg in PD drivers who experienced a SE while driving compared to 626 ± 667 mg in those who had not (P < 0.05). Similarly, ESS was significantly greater in drivers with a SE than in those without (11.6 ± 6.4 vs. 8.4 ± 4.1; P < 0.05). Logistic regression analysis demonstrated that ESS and mean daily L‐dopa dose equivalents were predictors of sleep episodes while driving, whereas age, gender, disease severity, and individual dopaminergic agents were not. These findings support the notion that sleep episodes while driving in PD patients are related to excess daytime sleepiness and dopaminergic load. Physicians should advise and treat patients accordingly. © 2003 Movement Disorder Society
Complex interactions in Parkinson's disease: A two‐phased approach
Authors: Maraganore Demetrius M. , de Andrade Mariza , Lesnick Timothy G. , Farrer Matthew J. , Bower James H. , Hardy John A. , Rocca Walter A.
Published: May 2003

The identification of pathogenic mutations in the three genes α‐synuclein, parkin, and ubiquitin carboxy‐terminal hydrolase L1 (UCHL1) has elucidated the ubiquitin proteasome system (UPS) and its potential role as a causal pathway in Parkinson's disease (PD). In addition, polymorphisms of these three genes have been shown to be independently associated with PD. In a sample of 298 unrelated PD cases and 185 controls, we applied a two‐phased approach of recursive partitioning and logistic regression analyses to explore complex interactions. For women only, we observed an epistatic interaction of UCHL1 and α‐synuclein genotypes with significant effects on PD risk (odds ratio = 2.42; P = 0.003). Our findings are consistent with the hypothesis that PD is a multigenic disorder of the UPS. © 2003 Movement Disorder Society
Painless legs and moving toes in a mother and her daughter
Authors: Dziewas Rainer , Kuhlenbäumer Gregor , Okegwo Angelika , Lüdemann Peter
Published: May 2003

Painful legs and moving toes (PLMT) is a rare syndrome which is characterised by involuntary movements of the toes and pain in the legs. We report on a mother and her daughter who both presented with involuntary movements of the toes similar to those seen in PLMT but without any associated pain. Neurological examination revealed intermittent 0.3 to 0.5‐Hz flexion and extension of the toes and ankles of the right foot in the mother, and of both feet in the daughter. In both patients, the movements appeared during periods of rest that were uncorrelated with the time of day. Diagnostic work‐up gave no evidence of radiculopathy or of focal neuropathy. Overnight polysomnography documented that movements of the toes and feet occurred only before sleep onset and during periods of nocturnal awakening or arousals. Because the movements observed in our patients were similar to those seen in patients with PLMT, we diagnosed an abortive form of this syndrome, which already has got the naming “painless legs and moving toes.” The occurrence in a mother and her daughter may point to a hereditary component of this disorder. © 2003 Movement Disorder Society
Platinum‐based anticancer agents: Innovative design strategies and biological perspectives
Authors: Ho Yee‐Ping , Au‐Yeung Steve C.F. , To Kenneth K.W.
Published: May 2003

The impact of cisplatin on cancer chemotherapy cannot be denied. Over the past 20 years, much effort has been dedicated to discover new platinum‐based anticancer agents that are superior to cisplatin or its analogue, carboplatin. Most structural modifications are based on changing one or both of the ligand types coordinated to platinum. Altering the leaving group can influence tissue and intracellular distribution of the drug, whereas the carrier ligand usually determines the structure of adducts formed with DNA. DNA–Pt adducts produced by cisplatin and many of its classical analogues are almost identical, and would explain their similar patterns of tumor sensitivity and susceptibility to resistance. Recently some highly innovative design strategies have emerged, aimed at overcoming platinum resistance and/or to introduce novel mechanisms of antitumor action. Platinum compounds bearing the 1,2‐diaminocyclohexane carrier ligand; and those of multinuclear Pt complexes giving rise to radically different DNA–Pt adducts, have resulted in novel anticancer agents capable of circumventing cisplatin resistance. Other strategies have focused on integrating biologically active ligands with platinum moieties intended to selectively localizing the anticancer properties. With the rapid advance in molecular biology, combined with innovation, it is possible new Pt‐based anticancer agents will materialize in the near future. © 2003 Wiley Periodicals, Inc. Med Res Rev, 23, No. 5, 633–655, 2003
Recent advances inde novodesign strategy for practical lead identification
Authors: Honma Teruki
Published: May 2003

De novodesign programs such as LEGEND, LUDI, and LeapFrog can identify novel structures that are predicted to fit the active site of a target protein. However, in the conventionalde novodesign strategy, the output structures obtained from the programs can be problematic with regard to synthetic accessibility and binding affinity prediction. Thus it has been practically difficult to obtain novel lead compounds that are appropriate for medicinal chemists through thede novodesign strategy. Since the late 1990s, several new strategies for lead identification have been reported and the successful examples have been disclosed. One of the strategies is validation of small fragments, which can be substructures ofde novoligands, by using NMR, X‐ray, or MS spectra. Another method is prioritization of output structures obtained fromde novodesign programs by chemical accessibility. This review describes these new strategies with practical applications and future perspectives ofde novodesign. © 2003 Wiley Periodicals, Inc. Med Res Rev, 23, No. 5, 606–632, 2003
Extraction of an avalanche diode noise model for its application as an on‐wafer noise source
Authors: Maya M. C. , Lázaro A. , Pradell L.
Published: May 2003

This paper presents a method to characterize the excess noise ratio (ENR) of an unmatched avalanche noise diode for application as an on‐wafer noise source. It is based on the determination of a broadband device noise circuit‐model from its measured reflection coefficient and noise powers. Measured ENR is used to calibrated a noise receiver up to 40 GHz. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 89–92, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10979
Design of a singly‐fed circularly polarized aperture‐coupled multilayer microstrip antenna for INMARSAT ground terminal applications
Authors: Zhang Yabin , Li Binhong , Liu Yijun
Published: May 2003

This paper presents a design procedure for a singly‐fed circularly polarized aperture‐coupled multilayer microstrip antenna (SF‐ACMMA) for INMARSAT ground terminal applications. In the design, low‐cost foam with low permittivity is used for enhancing the impedance bandwidth of antenna. The impedance bandwidth for VSWR ≤ 2 and circular polarization bandwidth for axial ratio (AR) ≤3 dB reach to 18.8% (1.45 to 1.75 GHz) and 12.3%, respectively. A gain of 9.4 dBi is also achieved. These measured results verify the applicability of design. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 92–95, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10980
Direct near‐field antenna testing and fault diagnosis by a silicon‐probe‐based optical sensing technique
Authors: Massa R. , Panariello G. , Rendina I.
Published: May 2003

A non‐perturbing, fast, low‐cost probe for near‐field measurements is presented in this paper. The new sensing technique's capabilities in antenna fault diagnosis and direct measurement of field intensity distribution at subwavelength distance from the sources are demonstrated by test measurement on different microwave antennas and applicators. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 95–98, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10981
A PIN PD microwave equivalent circuit model for optical receiver design
Authors: Jianjun Gao , Baoxin Gao , Chunguang Liang
Published: May 2003

A microwave equivalent circuit model for a PIN photodetector based on rate equations is presented using a SPICE simulator. The model is employed for 2.5‐Gb/s optical receiver design. The simulated frequency response performance of the receiver is in good agreement with measured results. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 102–104, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10984
A WDM network architecture with multiple receivers and a synchronous transmission protocol with constraint of data channel collision
Authors: Pountourakis Ioannis E.
Published: May 2003

A network control architecture for WDM passive star topology is introduced with a suitable network interface unit that reduces the headers' electronic processing bottleneck at each station. Also, a queueing model with receiver collision analysis for a synchronous transmission protocol which restricts data channel collision improving the system performance, is developed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 104–108, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10985
Wide‐angle solution of nonlinear coupled wave equations based on Padé approximants
Authors: Flamino Reinaldo S. , Alcantara Licinius D. S. , César Amílcar C. , Borges Ben‐Hur V.
Published: May 2003

A wide‐angle finite‐difference beam propagation method for the solution of coupled nonlinear wave equations is introduced in this paper. The formalism is expanded in terms of Padé approximants for the Crank–Nicolson scheme. An iterative algorithm is utilized to optimize convergence in the nonlinear region. The overall performance of the method is checked for a nonlinear X‐coupler. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 108–113, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10986
Compact dual‐band metal‐plate antenna for 2.4/5.2‐GHz WLAN operation
Authors: Su Chih‐Ming , Chen Wen‐Shyang , Wong Kin‐Lu
Published: May 2003

A novel compact dual‐band metal‐plate antenna is presented. The antenna is easily constructed by bending a metal plate, which consists of a longer arm as the grounding portion and two shorter arms as the major radiating portions for controlling the resonant modes at about 2.4 and 5.2 GHz, into a structure having a compact cross section of 1 × 3 mm2 and a length of 60 mm. The antenna is easily fed by using a 50Ω mini coaxial line, and is suitable to fit in possible narrow spaces within a communication device. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 113–115, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10987
A 3 × 3 integrated optical switch for a three‐axis fiber‐optic gyro
Authors: Fushen Chen , Qicong Li
Published: May 2003

A group of 3 × 3 integrated optical switches with the bifurcation optic active (BOA) structure of a zero‐gap directional coupler for a three‐axis fiber‐optic gyro is fabricated and demonstrated by using an x‐cut LiNbO3 substrate and 1.3‐μm optical wavelength. The technique of proton exchange on the LiNbO3 wafer is contributed to form a single‐polarization state for optical modes. Experimental results show that the devices with BOA structure have a low crosstalk and the more obvious advantages of decreasing the size, weight, and costs of fiber‐optic gyro. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 115–117, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10988
Application of optical computerized tomography in the heat elimination of an aeroengine blade
Authors: Hongbing Yao , Anzhi He
Published: May 2003

In this paper, optical computerized tomography (OCT) is first used for research on the heat elimination of a real aeroengine blade. The 3D temperature distribution and temperature topography of the blade are reconstructed. The results of the reconstruction match the measured results. This provides the experimental foundation for the design of an aeroengine blade. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 117–119, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10989
A triple‐band microstrip patch antenna
Authors: Row Jeen‐Sheen
Published: May 2003

A new integrated structure of a two‐element microstrip patch antenna with two feeds for wireless local network/global positioning system (WLAN/GPS) operations is proposed. The radiating element for dual‐band WLAN (2400–2483 MHz and 5150–5850 MHz) operations is a single‐feed planar inverted‐F antenna with a U‐shaped slot, which gives linearly polarized radiation. The second radiating element is a square microstrip patch with truncated corners for GPS operations at 1575 GHz, which provides circularly polarized broadside radiation patterns. The two radiating elements are integrated in the proposed antenna to have a compact structure. In addition, an isolation of better than −25 dB between the feed ports was also obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 120–123, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10990
A design for a high finesse parallel‐coupled microring resonator filter
Authors: Schwelb Otto , Frigyes István
Published: May 2003

Interaction between the circulating waves in microrings and the connecting busbars provides two parallel‐coupled microrings with filter characteristics that feature a stopband with uniformly large rejection and high finesse. Performance degradation due to waveguide and coupler loss and facet discontinuities have also been computed and found to be moderate. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 125–129, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10992
An optically controlled continuous phase‐shifter and magnitude controller on high‐resistive silicon
Authors: El Khaldi M. , Podevin F. , Vilcot A.
Published: May 2003

The optically controlled phase and magnitude of a coplanar transmitted wave have been investigated, taking advantage of the benefit of silicon photo‐absorption at 843 nm. A phase‐shift of 45° has been achieved at 12 GHz while the magnitude remains constant. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 129–132, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10993
Mode‐matching analysis of a new omnidirectional circular rod antenna with double dielectric gratings for millimeter‐wave application
Authors: Jing Hengzhen , Xu Shanjia
Published: May 2003

The radiation characteristics of a new millimeter‐wave omnidirectional circular rod antenna with double dielectric gratings are analyzed using the rigorous mode‐matching method. The results indicate that under the condition of the same radiation intensity, the double‐grating antenna has relatively smaller dimensions than that of the single one. This characteristic is of essential and practical significance in the case where limitation of the system's size and weight is strictly required. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 132–134, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10994
Broadband circularly polarized inverted‐L patch antenna
Authors: Su Che‐Wei , Chang Fa‐Shian , Wong Kin‐Lu
Published: May 2003

An innovative design of a corner‐truncated inverted‐L patch antenna for achieving circular polarization (CP) operation over a wide bandwidth is presented. The antenna has a thick air‐layer substrate; however, it can be easily excited using a probe feed with a short probe pin. CP operation is obtained by selecting an optimal size of the truncated corners, and good impedance matching over a wide bandwidth is obtained by using a beveling technique on the vertical portion of the inverted‐L patch. For a prototype constructed for wireless local area network (WLAN) operation in the 2.4‐GHz band (2.4–2.484 GHz), the obtained CP bandwidth (3‐dB axial ratio) reaches about 7%, and the measured antenna gain is about 8.0 dBi across the CP bandwidth. Details of the antenna design and the experimental results are presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 134–136, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10995
Coupling between dissimilar rectangular dielectric waveguides
Authors: Cory H. , Skorka O. , Sharkansky M.
Published: May 2003

The coupling between two identically excited, dissimilar rectangular dielectric waveguides, whose axes are parallel, is studied as a function of frequency and of the geometrical and the electrical properties of the structure. It is found that, for a given permittivity ratio, the power transfer between the guides is maximal, but not complete, at some particular frequency. It is also found that, for a given frequency, the power transfer between the guides is complete for the appropriate combination of permittivity and size of the guides, thus the same propagation coefficient is achieved for both. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 136–139, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10996
Design of dual‐polarization stacked arrays for ISM band applications
Authors: See T. S. P. , Ning Chen Zhi
Published: May 2003

In this paper, a dual linearly polarized stacked array for ISM band base station applications is presented. The patches on the bottom layer are fed diagonally by a microstrip line. A superstrate layer is stacked above the bottom layer to increase the operating bandwidth. The design parameters are simulated and optimized for the satisfactory impedance and radiation characteristics, which are compared against measured results. The measurements show that the antenna satisfies the requirements for a base station antenna and is capable of having broad bandwidth for the VSWR ≤ 1.5 with stable radiation patterns, low front‐to‐back ratios, and side‐lobe levels in the planes of interest. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 142–147, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10998
A miniaturized side‐coupled 45° Schiffman phase shifter on Teflon substrate
Authors: Chai Dongkyu , Yim Munhyuk , Linh Mai , Yoon Giwan
Published: May 2003

A novel side‐coupled 45° Schiffman phase shifter for 2.2‐GHz applications is presented with measurement results. The proposed phase shifter on a Teflon substrate is fabricated in a smaller area and more cost‐effective way, as compared to the conventional Schiffman phase shifter. In addition, the phase shifter seems very promising and useful, particularly for future 2.2‐GHz wireless applications and beyond. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 147–150, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10999
Improvement in second harmonics linearization technique for multichannel amplifiers
Authors: Males‐Ilic Natasa , Milovanovic Bratislav , Budimir Djuradj
Published: May 2003

A linearization technique that uses the injection of the fundamental signal second harmonics together with the fundamental signals at the amplifier input has been improved in this paper by introducing phase correction of the fundamental signals according to the differences in phases of the second harmonics. As the result, the improvement in third‐order intermodulation power levels is approximately 40 dB for analog and 22 dB for digitally modulated signals for multichannel applications. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 150–153, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11000
Evanescent modes stored in cavity resonators with backward‐wave slabs
Authors: Tretyakov S. A. , Maslovski S. I. , Nefedov I. S. , Kärkkäinen M. K.
Published: May 2003

As shown by N. Engheta, electromagnetic fields in two adjacent slabs bounded by two metal walls can satisfy the boundary conditions, even if the distance between the two walls is much smaller than the wavelength. This is possible if one of the slabs has a negative permeability. Here we show that these subwavelength “resonators” resonate only if the permeability of at least one of the slabs is frequency dependent. Thus, there is no advantage of using these structures as frequency‐selective devices. However, we have found that these systems can, in principle, be used as memory devices for evanescent fields, because the boundary conditions are identically satisfied for all plane evanescent waves inside the cavity. The physical meaning and practical limitations for possible realizations are discussed. The analysis is supported by FDTD simulations. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 153–157, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11001
Numerical calculation of leakage‐loss in W‐tunneling optical fibers
Authors: Minning Ji
Published: May 2003

A new numerical method based on point‐matching is presented to calculate leakage loss of fundamental mode in W‐tunneling optical fibers. Calculation stability is tested. The relationship between leakage loss and optical fiber parameter is shown by numerical calculation. Numerical and experimental results are compared and they agree well with each other. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 157–161, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11002
Design of a folded waveguide traveling‐wave tube
Authors: Han Seong‐Tae , Kim Jung‐II , Park Gun‐Sik
Published: May 2003

A method to synthesize the parameters of a folded waveguide traveling‐wave tube (FWTWT) is derived. For the device designed using this method, cold characteristics such as phase velocity and interaction impedance of virtual TM wave, as well as the growth rate, show reasonable agreement with those obtained by HFSS and MAGIC3D particle‐in‐cell (PIC) simulation, respectively. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 161–165, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11003
Efficacy of antibodies against Escherichia coli expressed chimeric recombinant protein encompassing multiple epitopes of zona pellucida glycoproteins to inhibit in vitro human sperm–egg binding
Authors: Sivapurapu Neela , Upadhyay Abhishek , Hasegawa Akiko , Koyama Koji , Gupta Satish K.
Published: May 2003

To minimize ovarian dysfunction subsequent to immunization with zona pellucida (ZP) glycoproteins, synthetic peptides encompassing the antigenic B cell epitopes as immunogens have been proposed. In this study, attempts have been made to clone and express a recombinant chimeric protein encompassing the epitopes corresponding to bonnet monkey (Macaca radiata) ZP glycoprotein‐1 (bmZP1, amino acid residues 132–147), ZP glycoprotein‐2 (bmZP2, amino acid residues 86–113), and ZP glycoprotein‐3 (bmZP3, amino acid residues 324–347). The above chimeric recombinant protein (r‐bmZP123) was expressed as a polyhistidine fusion protein in Escherichia coli. Immunoblot with murine monoclonal antibody, MA‐813, generated against recombinant bmZP1 revealed a major band of approximately 10 kDa. The r‐bmZP123 was purified on nickel‐nitrilotriacetic acid resin under denaturing conditions. The female rabbits immunized with purified r‐bmZP123 conjugated to diphtheria toxoid (DT) generated antibodies that reacted with r‐bmZP123 and DT in an ELISA. In addition, the immune sera also reacted with E. coli expressed recombinant bmZP1, bmZP2, and bmZP3. In an indirect immunofluorescence assay, the antibodies against r‐bmZP123 recognized native ZP of bonnet monkey as well as human. The immune sera also inhibited, in vitro, the binding of human spermatozoa to the human zona in the hemizona assay (HZA). These studies, for the first time, demonstrate the feasibility of assembling multiple epitopes of different ZP glycoproteins as a recombinant protein that elicit antibodies which are reactive with native zona and also inhibit, in vitro, human sperm–oocyte binding. Mol. Reprod. Dev. 65: 309–317, 2003. © 2003 Wiley‐Liss, Inc.
Cold‐induced calcium elevation triggers DNA fragmentation in immature pig oocytes
Authors: Mattioli Mauro , Barboni Barbara , Luisa Gioia , Loi Pasqualino
Published: May 2003

Fluo‐4 loaded immature oocytes were cooled from 30°C to various lower temperatures between 20 and 10°C and changes in intracellular calcium (Ca2+) levels were measured. Pig oocytes cooled to 14°C exhibited a clear biphasic Ca2+ rise. Lower temperatures produced similar responses, while higher temperatures did not exert any effect. The Ca2+ response appeared to rely on ryanodine dependent stores as removal of extracellular Ca2+ and intracytoplasmic injection of heparin did not modify cold‐induced Ca2+ elevation, while procaine or ruthenium red virtually eliminated the response. Confocal analysis of subcellular Ca2+ distribution during cooling revealed that the ion rises sharply within the nucleus. As Ca2+ imbalance may activate nuclear endonucleases, DNA integrity of cooled pig oocytes was evaluated by TUNEL and comet assays. Most cooled oocytes showed clear signs of DNA fragmentation. Oocytes injected with 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N′,N′‐tetracetic acid tetrapotassium salt (BAPTA), a Ca2+ chelator, maintained their DNA integrity thus confirming that intracellular Ca2+ is involved in triggering DNA fragmentation. The protective effect exerted by ruthenium red and/or procaine further confirmed this hypothesis. These data show that a moderate and transient cooling is sufficient to cause an intracellular Ca2+ rise that leads to DNA damage. The addition of inhibitors of ryanodine dependent Ca2+ stores may represent a valuable protective treatment to reduce chilling injuries. Mol. Reprod. Dev. 65: 289–297, 2003. © 2003 Wiley‐Liss, Inc.
Asynchronous cytoplast and karyoplast transplantation reveals that the cytoplasm determines the developmental fate of the nucleus in mouse oocytes
Authors: Cheng Yong , Fan Heng‐Yu , Wen Duan‐Cheng , Tong Chao , Zhu Zi‐Yu , Lei Lei , Sun Qing‐Yuan , Chen Da‐Yuan
Published: May 2003

The relationship between nucleus and cytoplasm can be well revealed by nuclear transplantation. Here, we have investigated the behavior changes of the reconstructed oocytes after transferring the karyoplasts from mouse GV, MI, and MII oocytes into the cytoplasts at the different developmental stages. When the GV cytoplast was used as recipient and MI or MII karyoplast was used as donor (MI‐GV pair and MII‐GV pair), the reconstructed pairs extruded a polar body after electrofusion and culture. Both the cytoplasm and the polar body had a metaphase spindle in the MI‐GV pair, while only a clutch of condensed chromatin was observed in the cytoplasm and polar body of the MII‐GV pair. When the MI cytoplast was used as recipient and GV or MII karyoplast was used as donor (GV‐MI pair and MII‐MI pair), the reconstructed pairs also extruded a polar body. Each had one spindle and a group of metaphase chromosomes in the cytoplasm and polar body, respectively. When the MII cytoplast was used as recipient and GV or MI karyoplast was used as donor (GV‐MII pair and MI‐MII pair), the reconstructed pairs were activated, became parthenogenetic embryos and even developed to hatching blastocysts after electrofusion. The result from immunoblotting showed that MAP kinase activity was high in the MI and MII cytoplasts, while not detected in GV cytoplast. The results demonstrate that the cytoplasmic environment determines the behavior of asynchronous donors. Mol. Reprod. Dev. 65: 278–282, 2003. © 2003 Wiley‐Liss, Inc.
Meiotic state of bovine oocytes is regulated by interactions between cAMP, cumulus, and granulosa
Authors: Aktas Huseyin , Leibfried‐Rutledge M. Lorainne , First Neal L.
Published: May 2003

Bovine oocytes are arrested at the prophase of first meiotic cell cycle. Meiosis resumes in oocytes of pre‐ovulatory follicles upon LH surge. However, oocytes from secondary follicles spontaneously resume meiosis in the absence of hormones if removed from the follicle and cultured in vitro. The nature of meiotic arrestor in bovine follicles is poorly understood. In this study we investigated the role of cell–cell interactions between granulosa and cumulus cells and the oocyte in mediating maintenance of meiotic arrest by cAMP. We sorted oocytes as granulosa–cumulus oocyte complexes (GCOC) if surrounded with cumulus cells attached to a large granulosa investment or cumulus oocytes complexes (COC) if surrounded with cumulus cells only and investigated the role cAMP in maintenance of meiotic arrest in these oocytes under various conditions. In hormone‐ and serum‐free medium both GCOC and COC enclosed oocytes resumed meiosis. When [cAMP]i was elevated with addition of invasive adenylate cyclase (iAC) GCOC enclosed oocytes were maintained in the prophase with intact germinal vesicle (GV) while COC enclosed oocytes underwent GV breakdown (GVBD). iAC elevated [cAMP]i in both types of oocytes to the same level. If oocytes were liberated from the cumulus and granulosa cells, they re‐initiated meiosis in serum and hormone free medium, but remained in the GV stage if iAC was added to the medium. Untreated GCOC and COC enclosed oocytes extruded first polar body at the same frequency in hormone‐supplemented media. GCOC and COC enclosed oocytes but not denuded oocytes (DO) cultured without somatic cells acquired developmental competence if cultured in hormone‐containing medium. It is concluded that maintenance of meiotic arrest is regulated by the interplay of [cAMP]i, and cumulus and granulosa cells. Mol. Reprod. Dev. 65: 336–343, 2003. © 2003 Wiley‐Liss, Inc.
Cloning and expression of cynomolgus monkey and baboon zona pellucida proteins
Authors: Harris Jeffrey D. , Piersen Colleen E.
Published: May 2003

Partial clones for the three cynomolgus monkey (Macaca fasicularis) zona pellucida genes (cmZPA, cmZPB, and cmZPC) have previously been isolated. These partial clones contained the sequences for the C‐terminal portion of each rcmZP protein. To obtain full‐length clones for each cmZP, a fresh cynomolgus monkey ovarian cDNA library was constructed. PCR methodology was employed to speed the isolation of full‐length clones for each cmZP cDNA. The 3′ primers were designed based on sequence information from the previously identified clones; the 5′ primers were designed using the human ZP sequences. The PCR technique yielded full‐length clones of cmZPA and cmZPC, but not of cmZPB. Therefore, a genomic clone of cmZPB was isolated and the sequence determined. The exon/intron structure is nearly identical to the human ZPB exon/intron structure. New PCR primers were designed based on the cynomolgus monkey ZPB genomic sequence, and a full‐length cmZPB cDNA was obtained. The same primers that were used to generate the cmZPB were also used to generate a baboon (Papio cynocephalus) ZPB (bZPB) cDNA. As was done previously for the human zona pellucida (hZP) cDNAs, the cmZP, and bZPB cDNAs were transferred to shuttle vectors for transfection into Chinese Hamster Ovary (CHO) cells. Stable cell lines for producing each ZP protein were isolated. Each cell line secreted the desired recombinant zona pellucida (rZP) protein into the culture medium, and each protein was purified using an established protocol. In terms of size and purity, the purified recombinant cmZP (rcmZP) and rbZPB proteins resemble the rhZP proteins. Mol. Reprod. Dev. 65: 237–244, 2003. © 2003 Wiley‐Liss, Inc.
Cell cycle dependent expression of Plk1 in synchronized porcine fetal fibroblasts
Authors: Anger Martin , Kues Wilfried A. , Klima Jiri , Mielenz Manfred , Kubelka Michal , Motlik Jan , Esner Milan , Dvorak Petr , Carnwath Joseph W. , Niemann Heiner
Published: May 2003

Enzymes of the Polo‐like kinase (Plk) family are active in the pathways controlling mitosis in several species. We have cloned cDNA fragments of the porcine homologues of Plk1, Plk2, and Plk3 employing fetal fibroblasts as source. All three partial cDNAs showed high sequence homology with their mouse and human counterparts and contained the Polo box, a domain characteristic for all Polo kinases. The expression levels of Plk1 mRNA at various points of the cell cycle in synchronized porcine fetal fibroblasts were analyzed by both RT‐PCR and the ribonuclease protection assay. Plk1 mRNA was barely detectable in G0 and G1, increased during S phase and peaked after the G2/M transition. A monoclonal antibody was generated against an in vitro expressed porcine Plk1‐protein fragment and used to detect changes in Plk1 expression at the protein level. Plk1 protein was first detected by immunoblotting at the beginning of S phase and was highest after the G2/M transition. In summary, the Plk1 expression pattern in the pig is similar to that reported for other species. The absence of Plk1 mRNA and protein appears to be a good marker for G0/G1 and thus for the selection of donor cells for nuclear transfer based somatic cloning. Mol. Reprod. Dev. 65: 245–253, 2003. © 2003 Wiley‐Liss, Inc.
Spermatid nuclear and sperm periaxonemal anomalies in the mouse Ube2b null mutant
Authors: Escalier Denise , Bai Xi‐Yuan , Silvius Derek , Xu Pin‐Xian , Xu Xin
Published: May 2003

Ube2b (yeast Ubc2b/Rad6 homolog) null mice were described previously. Ube2b encodes the murine ubiquitin conjugating enzyme mHR6B. Ube2b−/− mice were shown to present male infertility and their sperm head shape anomalies suggested that Ube2b may be involved in the replacement of nuclear proteins during spermatid chromatin condensation. Apoptosis of spermatocytes suggested additional targets of Ube2b during spermatogenesis. Consistently, we found Ube2b transcription in both meiotic and postmeiotic stages by in situ hybridization. Immuno‐electron microscopy revealed that transition proteins 1 and 2, protamines 1 and 2, and actin appear normally distributed during morphogenesis of Ube2b−/− spermatid heads. Surprisingly, electron microscopy revealed a particular sperm flagellum phenotype characterized by an abnormal distribution of periaxonemal structures. Flagellar anomalies of Ube2b null mice were previously described in infertile men indicating a possible genetic pathway for flagellar periaxonemal assembly in human. Mol. Reprod. Dev. 65: 298–308, 2003. © 2003 Wiley‐Liss, Inc.
Prolin‐rich tyrosine kinase 2 (PYK2) expression and localization in mouse testis
Authors: Chieffi Paolo , Barchi Marco , Di Agostino Silvia , Rossi Pellegrino , Tramontano Donatella , Geremia Raffaele
Published: May 2003

Prolin‐rich kinase 2 (PYK2) is a nonreceptor tyrosine kinase related to the focal adhesion kinase (FAK) p125FAK. PYK2 is rapidly phosphorylated on tyrosine residues in response to various stimuli, such as tumor necrosis factor‐α (TNF‐α), changes in osmolarity, elevation in intracellular calcium concentration, angiotensin, and UV irradiation. PYK2 has ligand sequences for Src homology 2 and 3 (SH‐2 and SH‐3), and has binding sites for paxillin and p130cas. Activation of PYK2 leads to modulation of ion channel function, phosphorylation of tyrosine residues, and activation of the MAP kinase signaling pathways. Immunocytochemistry shows that PYK2 is present in mouse germinal and Sertoli cells (ser). Northern blot and immunoprecipitation analysis demonstrate that, among germinal cells, PYK2 is more abundant in spermatocytes (spc) and spermatids (spt); in addition, immunofluorescence analysis clearly shows that the diffuse cytoplasmic localization of PYK2 changes in a specific cellular compartment in spt and spermatozoa. Mol. Reprod. Dev. 65: 330–335, 2003. © 2003 Wiley‐Liss, Inc.
Localization of glutamate cysteine ligase subunit mRNA within the rat ovary and relationship to follicular apoptosis
Authors: Luderer Ulrike , Diaz Dolores , Faustman Elaine M. , Kavanagh Terrance J.
Published: May 2003

Ovarian levels of the antioxidant tripeptide glutathione (GSH) increase following gonadotropin administration, suggesting that GSH synthesis in the ovary may be associated with follicular growth. In situ hybridization with 35S‐labeled riboprobes was used to localize ovarian mRNA expression of the catalytic and modulatory subunits of glutamate cysteine ligase (Gclc and Gclm), the rate‐limiting enzyme in GSH synthesis, during each stage of the rat estrous cycle. Gclm was highly expressed in the granulosa cells and oocytes of healthy, growing follicles, not in atretic follicles. Gclc was also highly expressed in follicles; however, unlike Gclm, Gclc was also expressed in corpora lutea and interstitial cells. In a subsequent experiment, the hypothesis that GSH synthesis occurs in healthy, but not in apoptotic, follicles was tested. Terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling (TUNEL) was used to detect apoptotic cells in the ovaries, and in situ hybridization for Gclm and Gclc was performed in adjacent sections of the same ovaries. TUNEL staining was found to be significantly associated with absence of Gclm hybridization in granulosa cells and oocytes and with lack of strong Gclc hybridization in granulosa cells. These results suggest that follicular apoptosis may be associated with down‐regulation of Gclm and Gclc transcription in granulosa cells and oocytes. Mol. Reprod. Dev. 65: 254–261, 2003. © 2003 Wiley‐Liss, Inc.
In vitro and in vivo effects of a multimerized αs1‐casein enhancer on whey acidic protein gene promoter activity
Authors: Pantano Thais , Rival‐Gervier Sylvie , Prince Sonia , Bourhis Celeste Menck‐Le , Maeder Caroline , Viglietta Céline , Houdebine Louis‐Marie , Jolivet Geneviève
Published: May 2003

Experimental data obtained in previous works have led to postulate that enhancers increase the frequency of action of a linked promoter in a given cell and may have some insulating effects. The multimerized rabbit αs1‐casein gene enhancer, the 6i multimer, was added upstream of the rabbit whey acidic protein gene (WAP) promoter (−6,300; +28 bp) fused to the firefly luciferase (luc) gene (6i WAP‐luc construct). The 6i multimer increased reporter gene expression in mouse mammary HC11 cells. In transgenic mice, a very weak but significant increase was also observed. More noticeable, no silent lines were found when the 6i multimer was associated to the WAP‐luc construct. This reflects the fact that the 6i multimer tends to prevent the silencing of the WAP‐luc construct. After addition of the 5′HS4 insulator region from the chicken β‐globin locus upstream of the 6i multimer, similar luciferase levels were measured in 6i WAP‐luc and 5′HS4 WAP‐luc transgenic mice. Our present data and previous ones, which show that the 6i multimer has no insulating activity on a TK gene promoter construct indicate that the insulating activity of the 6i multimer is construct‐dependent and not amplified by the 5′HS4 insulator. Mol. Reprod. Dev. 65: 262–268, 2003. © 2003 Wiley‐Liss, Inc.
Expression and role of calcium‐ATPase pump and sodium‐calcium exchanger in differentiated trophoblasts from human term placenta
Authors: Moreau Robert , Daoud Georges , Masse André , Simoneau Lucie , Lafond Julie
Published: May 2003

Although placental transfer of maternal calcium (Ca2+) is a crucial process for fetal development, the biochemical mechanisms are not completely elucidated. Especially, mechanisms of syncytiotrophoblast Ca2+ extrusion into fetal circulation remain to be established. In the current study we have investigated the characteristics of Ca2+ efflux in syncytiotrophoblast‐like structure originating from the differentiation of cultured trophoblasts isolated from human term placenta. Time‐courses of Ca2+ uptake by differentiated human trophoblasts displayed rapid initial entry (initial velocity (Vi) of 8.82 ± 0.86 nmol/mg protein/min) and subsequent establishment of a plateau. Ca2+ efflux studies with 45Ca2+‐loaded cells also showed rapid decline of cell‐associated 45Ca2+ with a Vi of efflux (Vie) of 8.90 ± 0.96 nmol/mg protein/min. Expression of membrane systems responsible for intracellular Ca2+ extrusion from differentiated human trophoblast were investigated by RT‐PCR. Messenger RNAs of four known isoforms of PMCA (PMCA 1–4) were detected. Messenger RNAs of two cloned human NCX isoforms (NCX1 and NCX3) were also revealed. More specifically, both splice variants NCX1.3 and NCX1.4 were amplified by PCR with total RNA of differentiated human trophoblast cells. Ca2+ flux studies in Na‐free incubation medium indicated that NCX played a minimal role in the cell Ca2+ fluxes. However, erythrosine B (inhibitor of PMCA) time‐ and dose‐dependently increased cell associated 45Ca2+ suggesting a principal role of plasma membrane Ca2+‐ATPase (PMCA) in the intracellular Ca2+ extrusion of syncytiotrophoblast‐like structure originating from the differentiation of cultured trophoblast cells isolated from human term placenta. Mol. Reprod. Dev. 65: 283–288, 2003. © 2003 Wiley‐Liss, Inc.
Successful development of viable blastocysts from enhanced green fluorescent protein transgene‐microinjected mouse embryos: Comparison of culture media
Authors: Devgan Vikram , Seshagiri Polani B.
Published: May 2003

To improve efficiency of transgenesis, we compared M16 and CZB embryo culture media, supporting development to blastocysts of FVB/N mouse pronuclear‐eggs, microinjected with enhanced green fluorescent protein (EGFP) transgene. When EGFP‐injected‐eggs were cultured (120 hr), blastocyst development was significantly (P < 0.03) higher in M16 medium (72.5 ± 2.4%) than that in CZB (13.2 ± 4.3%) or CZBG (CZB with 5.6 mM glucose at 48 hr culture) (62.1 ± 3.7%) media. Blastocyst development of noninjected embryos was higher in M16 (92.0 ± 2.6%) and CZBG (83.9 ± 3.9%) media than in CZB (31.9 ± 2.8%) medium (P < 0.0001). However, percentages of morulae at 72 hr were comparable in all treatments. Developed blastocysts were better in M16 than in CZB or CZBG media. Consistent with this, mean cell number per blastocyst, developed from injected embryos, was significantly (P < 0.002) higher in M16 medium (79.6), than those in CZB (31.3) or CZBG media (60.7); similar with noninjected embryos. Cell allocation to trophectoderm (TE) and inner cell mass (ICM), i.e., TE:ICM ratio, for injected blastocysts in M16 (3.0) was less than (P < 0.05) those in CZB (4.2) and CZBG (4.4) media; similar with noninjected blastocysts. Moreover, blastocysts, developed in M16 and CZBG media, hatched, attached, and exhibited trophoblast outgrowth; 18% of them showed EGFP‐expression. Importantly, blastocysts from M16 medium produced live transgenic “green” pups (11%) following embryo transfer. Taken together, our results indicate that supplementation of glucose, at 48 hr of culture (CZBG), is required for morula to blastocyst transition; M16 medium, containing glucose from the beginning of culture, is superior to CZB or CZBG for supporting development of biologically viable blastocysts from EGFP‐transgene‐injected mouse embryos. Mol. Reprod. Dev. 65: 269–277, 2003. © 2003 Wiley‐Liss, Inc.