bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency–time and time–space mappings for single‐shot coherent four‐wave mixing with chirped pulses and broad beams
Authors: Naumov A. N. , Zheltikov A. M.
Published: August 2002

The possibilities of using chirped pulses and broad beams for single‐shot measurements in coherent four‐wave mixing (FWM) are examined. The idea of such measurements is based on the fact that chirped pulses define a linear transform, mapping the difference between the instantaneous frequencies of pump pulses on to the delay time between these pulses. This delay between the pump pulses can be then mapped onto the spatial coordinate with the use of a broad‐beam FWM geometry. We consider various modifications of chirped‐pulse FWM techniques, including degenerate and non‐degenerate four‐wave mixing, coherent anti‐Stokes Raman scattering and Raman‐induced Kerr effect. The ways of extending the single‐shot broad‐beam FWM concept to multidimensional wave‐mixing techniques are discussed, and the possibilities of full reconstruction of the third‐order non‐linear optical susceptibility in the time domain as a function of its time variables for non‐stationary molecular systems are explored. Copyright © 2001 John Wiley & Sons, Ltd.
Theoretical analysis of resonant Raman scattering by 2LO phonons
Authors: Semenova L. E. , Prokhorov K. A.
Published: August 2002

A detailed theoretical treatment of the second‐order Raman efficiency is given for incident photon energies below an excitonic resonance. The Wannier excitons are considered as intermediate states in the scattering process. By using the Green's function method, the expression for the Raman efficiency is obtained. The contributions of the two sequences of the intermediate states, s–s–s and s–p–s, are analyzed. The second‐order Raman efficiency is calculated for CdS. Copyright © 2001 John Wiley & Sons, Ltd.
Applicability of microbiological assay and affinity chromatography purification followed by high‐performance liquid chromatography (HPLC) in studying folate contents in rye
Authors: Kariluoto M Susanna , Vahteristo Liisa T , Piironen Vieno I
Published: August 2002

In this study the folate contents in several rye varieties and their fractions were determined. Total folate content was analysed microbiologically using chloramphenicol‐resistant Lactobacillus rhamnosus as the growth organism. The amount of folate in rye grains was high, 630–780 µg kg−1, and variation between varieties was 8% (% CV). Affinity chromatography purification (with folate‐binding protein from bovine milk) followed by high‐performance liquid chromatography (HPLC) analysis proved to be an effective method for determining folate vitamers. 5‐Formyltetrahydrofolate showed a lower affinity to the folate‐binding protein than other vitamers; in order to obtain recoveries over 90%, the total folate load should not exceed 25% of the column capacity. Owing to intefering compounds, fluorescence detection was not always as specific as UV detection and thus not adequate for peak identification and quantitation alone. Formylated folates and 5‐methyltetrahydrofolate were the most abundant vitamers in rye, with tetrahydrofolate and folic acid representing only a minor proportion. However, different milling fractions had different folate vitamer distribution patterns. Both microbiological and HPLC methods were useful and reliable in determining folates in rye.

© 2001 Society of Chemical Industry
Bcl‐X expression in esophageal squamous cell carcinoma: Association with tumor progression and prognosis
Authors: Takayama Tomoyoshi , Nagao Mitsuo , Sawada Hidetomo , Yamada Yukishige , Emoto Kouji , Fujimoto Heisuke , Ueno Masato , Hirao Shuya , Nakajima Yoshiyuki
Published: August 2002

Background and Objectives:

Bcl‐2 family proteins are regulators of programmed cell death and important in the development and progression of human various tumors. The role of these proteins in the development, progression and differentiation of esophageal squamous cell carcinoma (ESCC) is unclear.

Methods:

We investigated the expression of Bcl‐2, Bcl‐X, and Bax using immunohistochemistry in 86 ESCCs, and scored the expression by the weighted score.

Results:

Bcl‐2 expression related to pT category (P=0.043) and histological grade (P = 0.001). Bcl‐X expression related to pT category (P = 0.003), pN category (P = 0.041) and the number of positive nodes (P = 0.036), and had a tendency to relate to histological grade (P = 0.086). Bax expression had a tendency to relate to pN category (P = 0.081). The inverse relationship between Bcl‐2 and Bcl‐X expression was detected (P = 0.001), while the positive one between Bcl‐X and Bax expression was detected (P = 0.014). Patients with low Bcl‐X weighted score had a significantly longer survival compared with those with high Bcl‐X weighted score. Multivariate analysis revealed Bcl‐X expression as the independent prognostic factors (P = 0.022).

Conclusion:

These results imply that Bcl‐2 family proteins, especially Bcl‐X, may contribute to the progression in ESCC. J. Surg. Oncol. 2001;78:116–123. © 2001 Wiley‐Liss, Inc.
Substituted p‐hydroquinones as a chain‐breaking antioxidant during the oxidation of styrene
Authors: Loshadkin Denis , Roginsky Vitaly , Pliss Evgeny
Published: August 2002

The technique based on monitoring oxygen consumption was applied to test 13 substituted p‐hydroquinones (QH2) as a chain‐breaking antioxidant during the oxidation of styrene initiated by 2,2′‐azobis(2,4‐dimethylvaleronitrile) at 37°C. The methodology originally developed to test monophenolic antioxidants was modified to fit it to specific features of oxidative transformation of QH2. Chain‐breaking capability of QH2 was characterized by two parameters: the rate constant k1 for reaction of QH2 with the peroxy radical LO2·: (1) QH2 + LO2· → QH· + LOOH and the stoichiometric factor of inhibition, f, which shows how many kinetic chains may be terminated by one molecule of QH2. Rate constants k1 × 105 (in M−1 s−1) were found to be 5.54 (nonsubstituted QH2); 7.13 (Me‐QH2); 13.1 (Et‐QH2); 12.0 (t‐Bu‐QH2); 15.6 (2,6‐Me2‐QH2); 18.8 (2,3‐Me2‐QH2); 17.1 (2,5‐Me2‐QH2); 13.7 (2,6‐(MeO)2‐QH2); 4.70 (2,6‐Ph2‐QH2); 0.90 (2,5‐Cl2‐QH2); 23.2 (Me3‐QH2); 4.40 (2,3‐(MeO)2‐5‐Me‐QH2). Parameter f never exceeds 2; for the majority of QH2, f was found to be visibly less than 2, decreasing when the rate of initiation decreased. Both experimental data and results of computer kinetic simulations suggest that, contrary to monophenolic antioxidants, the main path of QH· transformation is the self‐disproportionation rather than recombination of QH· with LO2·. Most likely, f is commonly lower than 2 because of the reaction of QH· with molecular oxygen. The latter may result in faster depletion of QH2 and the increase in the rate of inhibited oxidation. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 162–171, 2002; DOI 10.1002/kin.10041
Landscape ecological planning and design of degraded mining land
Authors: Wang Y. , Dawson R. , Han D. , Peng J. , Liu Z. , Ding Y.
Published: August 2002

Landscape ecology belongs to the macroecological spatial studies and its theory focuses on spatial heterogeneity and ecological holism. Landscape rehabilitation based on ecological planning and design can be used satisfactorily to restore degraded mining land to make it productive and reestablish a stable ecological equilibrium that is coordinated with its surroundings in order to attain ecological holism. Degraded mining land can be classified into diverse types, with different rehabilitation methods possible for each of the classifications. In addition, degraded mining lands are also associated with various types of landscape. Accordingly, landscape rehabilitation goals can only be realized by working out reasonable macrolandscape patterns and establishing suitable microecological conditions based on the landscape ecology. Copyright © 2001 John Wiley & Sons, Ltd.
Drought management in the Río Guadalhorce region of Andalucía, southern Spain
Authors: Roberts C. R.
Published: August 2002

The Guadalhorce catchment is characterized by hydrological extremes, severe flooding which has intermittently devastated the coastal conurbation of Málaga and riparian settlements upstream and periodic droughts of several years' duration. The region is also affected locally by high levels of salinity in soils and water. Attempts to manage this situation to permit economic development through agriculture and industry over several centuries seemed to have ameliorated the worst excesses and during the 20th century a series of major dam projects offered the potential for sustainable future economic growth. However, rapid population growth and shifting patterns of agriculture have brought the question of sustainability back on to the agenda.

This paper analyses the hydrological characteristics of the severe drought of the mid‐1990s, in terms of its impacts both on water quantity and water quality in the region. The strategies adopted to maintain domestic and tourist water supplies in the face of high demands from irrigation, particularly looking at the conjunctive use of groundwater, and the development of regional water grids are evaluated. The pressures on water quality, which developed in various parts of the Guadalhorce hydrological system, including in the main water supply network for the city, are also explored.

The paper concludes that the demands on the water supply system are unlikely to be manageable through current strategies and that ecological and water quality issues will probably prove more critical than water volumes in determining approaches to management of future droughts. Copyright © 2002 John Wiley & Sons, Ltd.
Comparison of 5‐aminolaevulinic acid and porphyrin photosensitization for photodynamic therapy of malignant bronchial stenosis: A clinical pilot study
Authors: Maier Alfred , Tomaselli Florian , Matzi V. , Woltsche M. , Anegg Udo , Fell B. , Rehak Peter , Pinter H. , Smolle‐Jüttner F.M.
Published: August 2002

Background and Objectives

Photosan®, a mixture of porphyrin oligomers as sensitizer for photodynamic therapy (PDT), carry the risk of prolonged photosensitivity of the skin. New sensitizer such as 5‐aminolaevulinic acid (ALA) with low rates of skin phototoxicity appear to be promising alternatives. The aim of this study was to evaluate the efficacy of ALA compared to Photosan for PDT in malignant tracheo‐bronchial stenosis. Reduction of tumor stenosis, increase in quality of life, and phototoxicity were considered as primary objectives. Improvement in clinical symptoms due to reduction of tumor stenosis, for example hemotysis, dyspnea, and poststenotic pneumonia were considered as secondary objectives.

Patients and Methods

After diagnostic work‐up, photosensitization was done in 16 patients with ALA (60 mg/kg BW, oral, 6–8 hours prior to PDT) and in 24 patients with Phtosan (2 mg/kg BW, i.v., 48 hours before PDT). The light dose was calculated as 100 J/cm2 tumor length. Light at 630 nm was applied using a pumped dye laser. In both groups, additional hyperbaric oxygenation was applied at a level of 2 absolute atmospheric pressure.

Results

Stenosis diameter and Karnofsky performance status showed a significant improvement in favor of the Photosan‐group, P = 0.00073 and 0.00015, respectively. In both groups no sunburn occurred due to phototoxicity of the sensitizer.

Conclusion

Despite the limitations of a non‐randomized study, photosensitization with Photosan seems to be more effective in PDT of malignant tracheo‐bronchial stenosis compared to ALA. Lasers Surg. Med. 30:12–17, 2002. © 2002 Wiley‐Liss, Inc.
Effects of laser irradiation on the spinal cord for the regeneration of crushed peripheral nerve in rats
Authors: Rochkind Semion , Nissan Moshe , Alon Malvina , Shamir Merav , Salame Khalil
Published: August 2002

Background and Objective

The purpose of the present study was to examine the recovery of the crushed sciatic nerve of rats after low‐power laser irradiation applied to the corresponding segments of the spinal cord.

Study Design/Materials and Methods

After a crush injury to the sciatic nerve in rats, low‐power laser irradiation was applied transcutaneously to corresponding segments of the spinal cord immediately after closing the wound by using 16 mW, 632 nm He‐Ne laser. The laser treatment was repeated 30 minutes daily for 21 consecutive days.

Results

The electrophysiologic activity of the injured nerves (compound muscle action potentials—CMAPs) was found to be approximately 90% of the normal precrush value and remained so for up to a long period of time. In the control nonirradiated group, electrophysiologic activity dropped to 20% of the normal precrush value at day 21 and showed the first signs of slow recovery 30 days after surgery. The two groups were found to be significantly different during follow‐up period (P < 0.001).

Conclusion

This study suggests that low‐power laser irradiation applied directly to the spinal cord can improve recovery of the corresponding insured peripheral nerve. Lasers Surg. Med. 28:216–219, 2001. © 2001 Wiley‐Liss, Inc.
Combination of dopamine transporter and D2 receptor SPECT in the diagnostic evaluation of PD, MSA, and PSP
Authors: Kim Yun J. , Ichise Masanori , Ballinger James R. , Vines Douglas , Erami Sean S. , Tatschida Tatsuro , Lang Anthony E.
Published: August 2002

It is often difficult to differentiate clinically between Parkinson's disease (PD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP).The objective of this work was to investigate whether combined pre‐ and postsynaptic dopaminergic single photon emission computed tomography (SPECT) scanning can reliably demonstrate changes in the nigrostriatal dopaminergic system and help differentiate between normal controls, PD, MSA, and PSP patients. We performed SPECT evaluation of the dopamine transporter (DAT) and dopamine D2 receptors (D2). SPECT scans using [123I]β‐CIT (for DAT) and [123I]IBF (for D2) were performed in 18 patients with PD (12 dopa‐naïve and 6 on levodopa and/or dopamine agonists), 7 with MSA of the striatonigral degeneration type, 6 with PSP, and 29 normal controls. Antiparkinsonian drugs were withheld for at least 12 hours before the scans. DAT and D2 binding potentials (Rv = V3/V2) were measured for caudate, anterior, and posterior putamen on the sides ipsilateral and contralateral to the worst motor symptoms. DAT binding in the posterior putamen was markedly reduced in all patients. However, D2 binding in posterior putamen was significantly increased in dopa‐untreated PD, being greater than the normal range in 4 of 12 (33%), and it was significantly reduced in MSA, being below the normal range in 5 of 7 (71%). None of the patients with PD showed reduced D2 binding below the normal range in posterior putamen. The degree of DAT binding could not discriminate between the patient groups. The ratio of posterior putamen to caudate percentage D2 Rv compared with the controls showed an opposite pattern between PD or PSP and MSA; the caudate was greater in 16 of 18 with PD and 6 of 6 with PSP, whereas caudate was less in 5 of 7 with MSA. These findings suggest that DAT SPECT may be useful in differentiating parkinsonism from controls and D2 SPECT in further differentiating MSA from Parkinson's disease and possibly PSP. © 2002 Movement Disorder Society.
Plasticity of afferent fibers to striatal neurons bearing D1 dopamine receptors in Parkinson's disease
Authors: Muriel Marie‐Paule , Agid Yves , Hirsch Etienne
Published: August 2002

The loss of dopaminergic neurons in the substantia nigra provokes a plasticity of corticostriatal synapses in Parkinson's disease (PD). The corticostriatal pathway nevertheless makes synapses with neurons bearing D1 dopamine receptors (D1R) and/or D2 dopamine receptors. At the ultrastructural level, we analyzed the morphological characteristics of synapses formed by afferent fibers making asymmetric contacts with the dendritic spines of neurons identified by D1R immunoreactivity, in the striatum of control subjects and PD patients. A quantitative analysis of the morphological characteristics of the synapses and of the number of perforated synapses (considered to be very active) was performed. In PD, a 50% increase in the number of perforated synapses making contact with D1R dendritic spines was observed, whereas no change in the number of perforated synapses on non‐D1R spines was observed. The change in the number of perforated synapses on D1R dendrites was associated with a slight but nonsignificant increase in the surface area of the corticostriatal afferent fibers and the surface of the mitochondria in these fibers (+29.0% and +34.6%, respectively). This suggests a hyperactivity of corticostriatal fibers in contact with D1R‐bearing neurons of the direct pathway in the basal ganglia circuitry. Since stimulation of the direct pathway is thought to alleviate the clinical symptoms of PD, this suggests that the differences observed may be involved in compensatory mechanisms. © 2001 Movement Disorder Society.
Piribedil for restless legs syndrome: A pilot study
Authors: Evidente Virgilio Gerald H.
Published: August 2002

Thirteen consecutive patients with restless legs syndrome (RLS) were treated with piribedil and were rated using an RLS rating scale (0–10) and subjective response (0–100%); 11/13 (85%) had improvement of their mean RLS scores with subjective response ranging from 30% to 100% (mean 74.6%). This pilot study suggests that piribedil is effective for RLS.
Transient improvement induced by motor fatigue in focal occupational dystonia: The handgrip test
Authors: Pesenti Alessandra , Priori Alberto , Scarlato Guglielmo , Barbieri Sergio
Published: August 2002

Muscle fatigue induced by a previous sustained contraction temporarily decreases the motor output, transiently worsening motor performance. Whether muscle fatigue alters motor performance also in dystonia—a disorder whose main pathophysiological abnormality is motor overflow—remains unknown. To assess the effects of muscle fatigue in patients with focal occupational upper limb dystonia, we studied the effect of a previous maximum fatiguing voluntary contraction on motor performance in 10 musicians with focal occupational dystonia, in 3 musicians with hand motor impairment due to non‐dystonic disorders, and in 5 normal musicians. The fatiguing task consisted of grasping a spring handgrip as long as possible until the task failed. In dystonic musicians, a fatiguing contraction significantly improved motor performance. The improvement lasted less than 5 minutes and appeared only after fatigue of the affected upper limb. In contrast, in musicians with non‐dystonic motor impairment, motor performance remained unchanged or worsened, and normal musician performance consistently worsened. © 2001 Movement Disorder Society.
Therapeutic ultrasound: Its application in drug delivery
Authors: Ng Ka‐yun , Liu Yang
Published: August 2002

Ultrasound is best known for its imaging capability in diagnostic medicine. However, there have been considerable efforts recently to develop therapeutic uses for it. The purpose of this review is to summarize some of the recent advances made in the area of therapeutic ultrasound as they relate to drug delivery. In particular, this review will focus on the applications of ultrasound to enhance the delivery and effect of three distinctive therapeutic drug classes: chemotherapeutic, thrombolytic, and gene‐based drugs. In addition, ultrasound contrast agents have been recently developed for diagnostic ultrasound. New experimental evidence suggests that these contrast agents can be used as exogenous cavitation nuclei for enhancement of drug and gene delivery. Thus, brief review of this new class of agents and their roles in drug delivery will also be provided. By comparison to diagnostic ultrasound, progress in therapeutic use of ultrasound has been somewhat limited. The recent successes in ultrasound‐related drug delivery research positions ultrasound as therapeutic tool for drug delivery in the future. © 2002 John Wiley & Sons, Inc. Med Res Rev, 22, No. 2, 204–223, 2002; DOI 10.1002/med.10004
Scaling limits for the Ruijgrok–Wu model of the Boltzmann equation
Authors: Gabetta Ester , Perthame Benoît
Published: August 2002

The Ruijgrok–Wu model of the kinetic theory of rarefied gases is investigated both in the fluid‐dynamic and hydro‐dynamic scalings. It is shown that the first limit equation is a first order quasilinear conservation law, whereas the limit equation in the diffusive scaling is the viscous Burgers equation. The main difficulties came from initial layers that we handle here. Copyright © 2001 John Wiley & Sons, Ltd.
Radiation resistance of coax‐fed rectangular microstrip patch antenna with the use of artificial neural networks
Authors: Pattnaik Shyam S. , Panda Dhruba C. , Devi S.
Published: August 2002

A novel method of using artificial neural networks (ANNS) for the calculation of the radiation resistance of a coax‐fed rectangular microstrip antenna is presented in this Letter. The network is trained with the results of three different antennas and tested for the fourth antenna. The tested results are in very good agreement. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 51–53, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10370
13C PHIP NMR spectra and polarization transfer during the homogeneous hydrogenation of alkynes with parahydrogen
Authors: Stephan Matthias , Kohlmann Olaf , Niessen Heiko G. , Eichhorn Andreas , Bargon Joachim
Published: August 2002

Homogeneously catalyzed hydrogenations of unsaturated substrates with parahydrogen not only lead to strong polarization signals in 1H NMR spectra, but also can give rise to strong heteronuclear polarization, especially if the hydrogenations are carried out in low magnetic fields. As a typical example, the polarization transfer from protons to carbon nuclei during the hydrogenation of alkynes is outlined for several substrates. In systems containing easily accessible triple bonds, e.g. phenylethyne or 3,3‐dimethyl‐1‐butyne, polarization transfer occurs to all carbon nuclei in the molecule. Accordingly, in NMR spectra recorded in situ all 13C resonances can be observed with good to excellent signal‐to‐noise ratios using only a single transient. The qualitative influence of symmetry and electronic aspects of the substrate and its hydrogenation product on the efficiency of the transfer of polarization to the 13C‐nuclei are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Oral antioxidants counteract the negative effects of female aging on oocyte quantity and quality in the mouse
Authors: Tarín Juan J. , Pérez‐Albalá Sonia , Cano Antonio
Published: August 2002

This study aims to compare the effect of early and late onset administration of oral antioxidants on number and quality of oocytes retrieved from aged mice after exogenous ovarian stimulation. Control hybrid females were fed a standard diet supplemented or not supplemented with pharmacological doses of vitamins C and E either from the first day of weaning or from the age of 32 weeks until they were autopsied at the age 40–42, 50–52, or 57–62 weeks after exogenous ovarian stimulation. Analysis of chromosomal distribution, DNA organization and cellular morphology was performed in ovulated cumulus‐enclosed and ‐free oocytes, ovarian non‐germinal vesicle oocytes enclosed by or free of mucous cumulus cells and in vitro‐matured ovarian germinal–vesicle oocytes. Both early and late onset administration of oral antioxidants counteracted the negative effects of female aging on number of ovarian oocytes and total percentage of oocytes retrieved from oviducts and ovaries exhibiting a normal distribution of chromosomes in the metaphase‐II plate and/or morphological traits of apoptosis. Although both early and late onset administration of oral antioxidants can counteract the negative effects of female aging on number and quality of oocytes, transference of these results to human beings should be made with caution because of the potential side effects of high doses of vitamins on reproductive function as well as many other undesirable systemic disorders. Mol. Reprod. Dev. 61: 385–397, 2002. © 2002 Wiley‐Liss, Inc.
Protection against reactive oxygen species during mouse preimplantation embryo development: Role of EDTA, oxygen tension, catalase, superoxide dismutase and pyruvate
Authors: Orsi Nicolas M. , Leese Henry J.
Published: August 2002

Oxidative damage due to the production of reactive oxygen species (ROS) is one of a number of culture‐induced stresses which may compromise preimplantation embryo development in vitro. Ethylenediaminetetraacetic acid (EDTA), reduced oxygen tension, superoxide dismutase (SOD) and catalase (CAT) offer protection against oxidative stress, but few attempts have been made to determine which of these agents, or which combination, is the most effective. In particular, no systematic investigation of their actions and interactions has been made using a multifactorial experimental design. Murine zygotes were cultured in the presence or absence of 10 μM EDTA, SOD (100–7,000 U/ml) and CAT (50–100 U/ml) at atmospheric (20%) and reduced (5%) oxygen tensions. Blastocyst formation and hatching rates (at various time points), and cell numbers were recorded, whilst parallel groups of embryos had their consumption of pyruvate, a hydrogen peroxide scavenger, measured. All parameters interacted significantly and affected blastocyst formation, hatching rate and cell numbers but the effect of EDTA was the most pronounced. There were beneficial effects of 5% O2, CAT and SOD, while 20% O2 had a deleterious effect on development. EDTA improved blastocyst formation and hatching rates but paradoxically led to a reduction in cell number. 5% O2 was the next most significant parameter to enhance embryo development and also increased cell numbers. No differences in pyruvate uptake were apparent between the various treatment groups. The results suggest that embryo culture in EDTA‐free medium under 5% O2 provides the most practical and physiological conditions for in vitro murine embryo culture. Mol. Reprod. Dev. 59:44–53, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of the Stag3 gene and the synaptonemal complex in a rat model (as/as) for male infertility
Authors: Bayés Mònica , Prieto I. , Noguchi J. , Barbero J.L. , Jurado L.A. Pérez
Published: August 2002

Affected males (as/as) from the mutant TT rat strain are sterile due to spermatogenesis impairment with meiotic arrest at the pachytene stage. The as locus is on rat chromosome 12, in a region that shows conserved synteny to cM 74–94 on mouse chromosome 5. Stag3, a new member of the stromalin protein family, is expressed specifically in testis and associates to the synaptonemal complex. Mouse Stag3 gene has been assigned to cM 78 on chromosome 5. In this study, we have characterized the rat Stag3 gene and examined it as a candidate for male infertility in as/as rats. The rat Stag3 cDNA is 4181 nucleotides long, contains a highly polymorphic hexanucleotide repeat in the coding region, and encodes a 1256 amino acid protein with 93 and 77% sequence identity to mouse and human Stag3 proteins, respectively. No mutations or differences in size or abundance of Stag3 mRNA were detected between as/as and control rats, suggesting that Stag3 is not responsible for the aspermic phenotype. In addition, immunohistochemistry with antibodies against SCP1 and SPC3 proteins suggest that the synaptonemal complex structures are not primarily affected in these rats. Mol. Reprod. Dev. 60:414‐417, © 2001 Wiley‐Liss, Inc.
Imaging cortical association tracts in the human brain using diffusion‐tensor‐based axonal tracking
Authors: Mori Susumu , Kaufmann Walter E. , Davatzikos Christos , Stieltjes Bram , Amodei Laura , Fredericksen Kim , Pearlson Godfrey D. , Melhem Elias R. , Solaiyappan Meiyappan , Raymond Gerald V. , Moser Hugo W. , van Zijl Peter C.M.
Published: August 2002

Diffusion‐tensor fiber tracking was used to identify the cores of several long‐association fibers, including the anterior (ATR) and posterior (PTR) thalamic radiations, and the uncinate (UNC), superior longitudinal (SLF), inferior longitudinal (ILF), and inferior fronto‐occipital (IFO) fasciculi. Tracking results were compared to existing anatomical knowledge, and showed good qualitative agreement. Guidelines were developed to reproducibly track these fibers in vivo. The interindividual variability of these reconstructions was assessed in a common spatial reference frame (Talairach space) using probabilistic mapping. As a first illustration of this technical capability, a reduction in brain connectivity in a patient with a childhood neurodegenerative disease (X‐linked adrenoleukodystrophy) was demonstrated. Magn Reson Med 47:215–223, 2002. © 2002 Wiley‐Liss, Inc.
Quantitative MRI assessment of leukoencephalopathy
Authors: Reddick Wilburn E. , Glass John O. , Langston James W. , Helton Kathleen J.
Published: August 2002

Quantitative MRI assessment of leukoencephalopathy is difficult because the MRI properties of leukoencephalopathy significantly overlap those of normal tissue. This report describes the use of an automated procedure for longitudinal measurement of tissue volume and relaxation times to quantify leukoencephalopathy. Images derived by using this procedure in patients undergoing therapy for acute lymphoblastic leukemia (ALL) are presented. Five examinations from each of five volunteers (25 examinations) were used to test the reproducibility of quantitated baseline and subsequent, normal‐appearing images; the coefficients of variation were less than 2% for gray and white matter. Regions of leukoencephalopathy in patients were assessed by comparison with manual segmentation. Two radiologists manually segmented images from 15 randomly chosen MRI examinations that exhibited leukoencephalopathy. Kappa analyses showed that the two radiologists' interpretations were concordant (κ = 0.70) and that each radiologist's interpretations agreed with the results of the automated procedure (κ = 0.57 and 0.55).The clinical application of this method was illustrated by analysis of images from sequential MR examinations of two patients who developed leukoencephalopathy during treatment for ALL. The ultimate goal is to use these quantitative MR imaging measures to better understand therapy‐induced neurotoxicity, which can be limited or even reversed with some combination of therapy adjustments and pharmacological and neurobehavioral interventions. Magn Reson Med 47:912–920, 2002. © 2002 Wiley‐Liss, Inc.
Steady‐state preparation for spoiled gradient echo imaging
Authors: Busse Reed F. , Riederer Stephen J.
Published: August 2002

While spoiled gradient echo sequences provide a rapid means of acquiring T1‐weighted images, it is often desirable that the magnetization be in the steady state to avoid artifacts. For some applications, this requires many “dummy” repetitions of the pulse sequence prior to data collection, delaying image acquisition. A method is presented in which a saturation pulse, followed by a prescribed recovery period, places longitudinal magnetization levels of all materials near steady state, ready for data acquisition much sooner than when employing only dummy repetitions to achieve steady state. Effects of transverse coherences are studied using configuration theory. The method is shown to be effective in both phantom studies and in vivo applications, including real‐time imaging, multiphase cardiac imaging, and triggered contrast‐enhanced angiography. Magn Reson Med 45:653–661, 2001. © 2001 Wiley‐Liss, Inc.
Cesium‐133: A potential reporter of the hepatic uptake of contrast agents
Authors: Colet Jean‐Marie , Lecomte Sophie , Vander Elst Luce , Muller Robert N.
Published: August 2002

NMR spectroscopy of intracellularly located 133Cs has been used to monitor the uptake of Gd‐EOB‐DTPA by the isolated rat liver. As shown by 31P spectroscopy, accumulation of 133Cs ions in hepatocytes does not produce detectable effects on the metabolism. The hepatic internalization of Gd‐EOB‐DTPA was followed by the paramagnetic relaxation enhancement of the intracellular 133Cs ions, and confirmed by parallel quantitations of Gd and Cs run by inductively coupled plasma (ICP) analysis of liver samples and aliquots of perfusate. The relaxation data significantly underestimate the Gd content, suggesting a potential compartmentation of Cs+ and/or the contrast agent. Magn Reson Med 45:711–715, 2001. © 2001 Wiley‐Liss, Inc.
Measuring the human retinal oxygenation response to a hyperoxic challenge using MRI: Eliminating blinking artifacts and demonstrating proof of concept
Authors: Berkowitz Bruce A. , McDonald Christopher , Ito Yasuki , Tofts Paul S. , Latif Zahid , Gross Jason
Published: August 2002

The retinal oxygenation response to a hyperoxic challenge measured using MRI appears to be an early and accurate marker of retinopathy risk in experimental models, with promising clinical potential. However, the application of this technique in humans is limited by blinking artifacts that can confound detection of subtle signal intensity changes. We asked subjects to refrain from blinking during a 12‐s fast low‐angle shot (FLASH) image, and to blink if needed during the following 3‐s rest period. This no‐blink blink cycle was repeated sequentially 20 times during either room‐air or 100% oxygen breathing. Significant change (P < 0.05) was detected for the first time from the resultant blinking‐artifact‐free images in the preretinal vitreous oxygen tension (upper limit of about 13 mm Hg (1.8 KPa, N = 3)) following a 10‐min hyperoxic inhalation challenge. These results provide the proof‐of‐concept data needed for future MRI evaluation of the retinal oxygenation response and human retinopathy, such as diabetic retinopathy. Magn Reson Med 46:412–416, 2001. © 2001 Wiley‐Liss, Inc.
Assessment of 3D proton MR echo‐planar spectroscopic imaging using automated spectral analysis
Authors: Ebel Andreas , Soher Brian J. , Maudsley Andrew A.
Published: August 2002

For many clinical applications of proton MR spectroscopic imaging (MRSI) of the brain, diagnostic assessment is limited by insufficient coverage provided by single‐ or multislice acquisition methods as well as by the use of volume preselection methods. Additionally, traditional spectral analysis methods may limit the operator to detailed analysis of only a few selected brain regions. It is therefore highly desirable to use a fully 3D approach, combined with spectral analysis procedures that enable automated assessment of 3D metabolite distributions over the whole brain. In this study, a 3D echo‐planar MRSI technique has been implemented without volume preselection to provide sufficient spatial resolution with maximum coverage of the brain. Using MRSI acquisitions in normal subjects at 1.5T and a fully automated spectral analysis procedure, an assessment of the resultant spectral quality and the extent of viable data in human brain was carried out. The analysis found that 69% of brain voxels were obtained with acceptable spectral quality at TE = 135 ms, and 52% at TE = 25 ms. Most of the rejected voxels were located near the sinuses or temporal bones and demonstrated poor B0 homogeneity and additional regions were affected by stronger lipid contamination at TE = 25 ms. Magn Reson Med 46:1072–1078, 2001. © 2001 Wiley‐Liss, Inc.
Effect of exercise on stability of chronically enlarged motor units
Authors: Tam Siu Lin , Archibald Vey , Tyreman Neil , Gordon T.
Published: August 2002

Chronic denervation syndromes such as the post‐polio syndrome are associated with progressive muscle weakness and fatigue after motoneuron death. Neither the etiology nor the management of these syndromes is clear. To address this issue, we partially denervated rat hindlimb muscles for 1 or 12 months and examined whether chronically enlarged motor units (MUs) become destabilized with time and further destabilized by daily running on exercise wheels. MU enlargement, measured electrophysiologically and morphologically was significantly reduced at 12 months in extensively denervated muscles, and to a lesser extent in moderately denervated muscles, as compared to the findings at 1 month. A 1‐month period of running exercise further reduced the size of the chronically enlarged MUs in the extensively denervated muscles. We have therefore (1) successfully established a rat model of time‐related MU size reduction, in which destabilization of chronically enlarged MUs results in loss of axonal terminals, and (2) demonstrated that nonphysiological activity has small but significant effects of further destabilizing the chronically enlarged MUs. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002 DOI 10.1002/mus.10057
Presymptomatic motor neuron loss and reactive astrocytosis in the SOD1 mouse model of amyotrophic lateral sclerosis
Authors: Feeney Sandra J. , McKelvie Penelope A. , Austin Lawrence , Jean‐Francois M.J. Bernadette , Kapsa Robert , Tombs Stefania M. , Byrne Edward
Published: August 2002

In familial amyotrophic lateral sclerosis (fALS), there is a need to establish more precisely the progression of the disease, particularly whether there is gradual presymptomatic neuronal loss or an abrupt loss coinciding with the symptomatic stage. To elucidate this, we investigated the progression of motor neuron loss through morphological techniques, reactive astrocytosis, and expression of ubiquitin and neurofilament proteins, by immunohistochemistry, in SOD1 G93A mice with a protracted disease course and control mice. Loss of motor neurons in SOD1 G93A mice followed a biphasic progression, with an initial loss at 126 days of age, followed by a gradual loss from onset of symptoms through to end‐stage disease. Reactive astrocytosis was first observed at 70 days of age and showed a gradual increase through to end‐stage disease. This suggests that there is a need for early detection of fALS cases, and potential therapeutic treatments may be more beneficial if administered at an early stage. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1510–1519, 2001
Distal excitability properties of median motor axons
Authors: Walters R. Jon L. , Kiernan Matthew C. , Murray Nicholas M.F. , Bostock Hugh
Published: August 2002

Excitability properties were recorded from 14 volunteers following stimulation of the recurrent motor branch of the median nerve in the palm. Distal stimulation resulted in significantly lower strength‐duration time constant and lower threshold during prolonged hyperpolarization than did wrist stimulation in the same subjects. These differences may be geometric in origin or alternatively may arise from functional changes distally, particularly reduced expression of persistent Na+ conductances and more hyperpolarization‐activated current. Excitability studies using palm stimulation provide information closer to the neuromuscular junction, where membrane properties are preferentially affected in a variety of clinical conditions. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1695–1698, 2001
Interactions between prostate volume, filling cystometric estimated parameters, and data from pressure‐flow studies in 565 men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia
Authors: Eckhardt Mardy D. , Venrooij Ger E.P.M. van , Boon Tom A.
Published: August 2002

The aim of this study was to establish the characteristics and to investigate the interactions between prostate volume, degree of obstruction, bladder contractility, the prevalence of residual volume, bladder compliance, bladder capacities, and the prevalence of instability in a large, well‐defined group of men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). The 565 consecutive men included in this study met the criteria of the International Consensus Committee on BPH and voided more than 150 mL during uroflowmetry. Their residual urine volume and prostate size were estimated, and filling cystometry and pressure‐flow studies were performed. Fifty‐three percent of the men appeared to have obstruction. We found a positive correlation between prostate volume and Schäfer's obstruction grade, except that mean prostate volume decreased at Schäfer's grades 5 and 6. Significant negative correlations existed between Schäfer's grade and cystometric bladder capacity and effective capacity. Bladder outlet obstruction results in incomplete emptying. Of all men, 26% had a significant residual volume ( > 20% of cystometric capacity). Thirty‐nine percent did not have residual volume. Of the 565 men, 46% had an unstable bladder. In particular, patients with an unstable bladder in the sitting and lying positions have a significantly higher Schäfer's grade and contractility grade and a significantly lower cystometric and effective bladder capacity compared with patients without instability. Patients with a residual volume or instability were significantly older. We conclude that in men with LUTS suggestive of BPH, abnormalities of bladder and bladder outlet function vary greatly and have complex mutual interactions. Neurourol. Urodynam. 20:579–590, 2001. © 2001 Wiley‐Liss, Inc.
Protocol for clinical neurophysiologic examination of the pelvic floor
Authors: Podnar Simon , Vodušek David B.
Published: August 2002

Clinical neurophysiologic examination of the pelvic floor is performed worldwide, but there is no consensus on the choice of tests, nor on technical details of individual methods. Standardized methods are, however, necessary to obtain their valid application in different laboratories for the purpose of collection of normative data, comparison of patient data and organization of multi‐center studies. It is proposed that in patients with suspected “lower motor neuron” type lesions concentric needle electromyography (CNEMG) is the most informative test to detect pelvic floor denervation/reinnervation, and the external anal sphincter (EAS) muscle is the most appropriate muscle to be examined (either in isolation—when a selective lesion is suspected—or in addition to examination of other muscles). An algorithm consisting of standardized tests including a standardized approach to CNEMG examination of the EAS is presented. The proposed electrophysiologic assessment consists of a computer‐assisted analysis of denervation and reinnervation features of the CNEMG signal, a qualitative assessment of reflex and voluntary activation of EAS motor units, and of electrical (or mechanical) elicitation of the bulbocavernosus reflex in those patients in whom manual anogenital stimulation failed to elicit a robust response in the EAS. The proposed protocol could serve as a basis for further studies on validity, sensitivity and specificity of electrophysiologic assessment in patients with different types of “lower motor neuron” involvement of pelvic floor muscles and sacral dysfunction. Neurourol. Urodynam. 20:669–682, 2001. © 2001 Wiley‐Liss, Inc.
Antiandrogen blocks estrogen‐induced masculinization of the song system in female zebra finches
Authors: Grisham William , Lee Janet , McCormick Mary Ellen , Yang‐Stayner Kay , Arnold Arthur P.
Published: August 2002

Song behavior and the neural song system that serves it are sexually dimorphic in zebra finches. In this species, males sing and females normally do not. The sex differences in the song system include sex differences in the proportion of neurons that express androgen receptors, which is higher in specific brain regions of males. Estradiol (E2) administered in early development profoundly masculinizes the song system of females, including the proportion of neurons expressing androgen receptors. We examined whether or not the expression of these androgen receptors was causally related to the E2‐induced masculinization of this system by coadministering Flutamide, which blocks androgen action at the receptor, along with E2 at hatching. E2 alone had its usual masculinizing effect on the female song system, measured in adulthood: increasing the size of song nuclei, the size of neurons in HVC, RA, and lMAN, and the number of neurons in HVC. E2's masculinizing action, however, was significantly diminished on all measures by coadministering Flutamide. Indeed, females receiving both E2 and Flutamide were never significantly more masculine than controls on any measure. Flutamide alone had no effect. Our results strongly suggest that the activation of androgen receptors is necessary for the E2‐induced masculinization of the song system in females. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 1–8, 2002
Developmental and hormonal regulation of NR2A mRNA in forebrain regions controlling avian vocal learning
Authors: Heinrich J. E. , Singh T. D. , Sohrabji F. , Nordeen K. W. , Nordeen E. J.
Published: August 2002

Developmental changes in the composition of NMDA receptors can alter receptor physiology as well as intracellular signal transduction cascades, potentially shifting thresholds for neural and behavioral plasticity. During song learning in zebra finches, NMDAR currents become faster, and transcripts for the modulatory NR2B subunit of this receptor decrease in lMAN, a region in which NMDAR activation is critical for vocal learning. Using in situ hybridization, we found that NR2A transcripts change reciprocally, increasing significantly in both lMAN (59%) and in another song region, Area X (38%), between posthatch day (PHD) 20 and 40, but not changing further at PHD60 or 80. In adjacent areas not associated with song learning, NR2A mRNA did not change between PHD20–80. Although early song deprivation (which extends the sensitive period for song learning) delays changes in NR2B gene expression and NMDAR physiology within the lMAN, it did not alter NR2A mRNA levels measured at PHD40, 45, or 60. Early testosterone (T) treatment, which disrupts vocal development and accelerates the maturation of both NR2B levels and NMDAR physiology in lMAN, also significantly increased NR2A transcripts measured at PHD35 in lMAN. In Area X, a similar effect of T approached significance. Together with our previous studies, these results show that in a pathway critical for vocal plasticity, the ratio of NR2A:NR2B mRNA rises abruptly early during the sensitive period for song learning. Furthermore, androgen regulation of NMDAR gene expression may alter thresholds for experience‐dependent synaptic change. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 149–159, 2002
Digger wasp versus cricket: Mechanisms underlying the total paralysis caused by the predator's venom
Authors: Ferber Michael , Hörner Michael , Cepok Sabine , Gnatzy Werner
Published: August 2002

The data presented here describe neurophysiological experiments addressing the question of cellular mechanisms underlying the total paralysis of locomotor behavior in crickets occurring after being stung by females of the digger wasp species Liris niger. The Liris venom effects have been studied by both in vivo recordings from identified neurons of the well‐described giant fiber pathway and in vitro recordings from cultured neurons isolated from the terminal ganglion of crickets. The total paralysis of the prey is characterized by a general block of action potential generation as well as by a block of synaptic transmission. Intracellular recordings from neurons in intact ganglia under single electrode voltage‐clamp conditions, as well as whole‐cell patch‐clamp recordings from cultured cricket neurons consistently show that the block of action potential generation by the Liris venom is due to a block of voltage‐gated sodium inward currents in neurons of the stung ganglia. Furthermore, our data provide evidence that the Liris venom also blocks calcium currents in identified neurosecretory neurons. On the other hand, outward currents are not affected by the Liris venom. The in vitro recordings suggest that the Liris venom contains active venom components, which, at least for the observed block of inward currents, do not require a metabolic modification. Because venom application does not affect the ACh‐induced EPSPs in giant interneurons, the Liris venom does not seem to influence the postsynaptic ACh receptors. The possible pre‐ and postsynaptic sites of venom action and the functional consequences on synaptic transmission within the giant fiber system are discussed. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 207–222, 2001