bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of regional pulmonary parenchymal strain during normal respiration using spin inversion tagged magnetization MRI
Authors: Napadow Vitaly J. , Mai Vu , Bankier Alex , Gilbert Richard J. , Edelman Robert , Chen Qun
Published: August 2002

In clinical practice, the assessment of lung mechanics is limited to a global physiological evaluation, which measures, in the aggregate, the contributions of the pulmonary parenchyma, pleura, and chest wall. In this study, we used an MR imaging methodology which applies two‐dimensional bands of inverted magnetization directly onto the pulmonary parenchyma, thus allowing for the quantification of local pulmonary tissue deformation, or strain, throughout inhalation. Our results showed that the magnitude of strain was maximal at the base and apex of the lung, but was curtailed at the hilum, the anatomical site of the poorly mobile bronchial and vascular insertions. In‐plane shear strain mapping showed mostly positive shear strain, predominant at the apex throughout inhalation, and increasing with expanding lung volume. Anisotropy mapping showed that superior‐inferior axial strain was greater than medial‐lateral axial strain at the apex and base, while the opposite was true for the middle lung field. This study demonstrates that localized pulmonary deformation can be measured in vivo with tagging MRI, and quantified by applying finite strain definitions from continuum mechanics. J. Magn. Reson. Imaging 2001;13:467–474. © 2001 Wiley‐Liss, Inc.
Role of amino acid N‐methylation in cyclosporins on ring opening and fragmentation mechanisms during collisionally induced dissociation in an ion trap
Authors: Kuzma Marek , Jegorov Alexandr , Hesso Antti , Tornaeus Jarkko , Sedmera Petr , Havlíček Vladimír
Published: August 2002

The product ion mass spectra (collisionally induced dissociation mass spectra) of 12 different cyclosporins modified at every N‐methylated amino acid residue with respect to cyclosporin A were compared and the effect of N‐demethylation on ring opening mechanisms was evaluated. The four preferential protonation sites were identified in [MeBmt1]‐cyclosporins. Three sites represented the N‐methylated nitrogens of Sar3, MeLeu6 and MeLeu9, while the remaining one represented the lactone group formed by the intramolecular N,O‐acyl shift. Selective N‐demethylation resulted either in the deletion of the entire fragment ion series or its substantial attenuation. The structures of three new natural cyclosporins in the study were supported by NMR data. Copyright © 2002 John Wiley & Sons, Ltd.
Novel TTV variants isolated in an epidemic of hepatitis of unknown etiology
Authors: Liu Zhihua , Luo Kangxian , Zheng Ruidan , Hu Jing , He Haitang
Published: August 2002

TT virus (TTV) is a recently discovered single‐stranded DNA virus that has been reported to be associated with elevated transminase levels in the patients with posttransfusion hepatitis of unknown etiology. TTV prevalence is very high in the common population and its pathogenicity remains unclear. In this study, we performed an epidemiological study to investigate the infection rate of TTV and its role in an epidemic of unknown‐etiology hepatitis. Moreover, two TTV isolates named L01 and L02 were cloned from the serum of a patient with unknown‐etiology hepatitis. Eighty‐one subjects were included in the study and were divided into two groups: 18 in the case group and 63 in the control group. TTVDNA was detected by nested PCR from sera samples. The infection rates of TTV in case and control groups were 33.3 and 38.9%, respectively. There was no significant difference between the two groups. Homology analysis showed that L01 had a very poor homology with other TTV isolates and L02, and L02 was 75.5% identical to JA10. The result does not support TTV as a causative agent in this epidemic. The genetic divergence between L01 and other TTV isolates beyond genotype, so it represents a new genotype of TTV. J. Med. Virol. 67:113–117, 2002. © 2002 Wiley‐Liss, Inc.
Overexpression of neurofilament H disrupts normal cell structure and function
Authors: Szebenyi Györgyi , Smith George M. , Li Ping , Brady Scott T.
Published: August 2002

Studying exogenously expressed tagged proteins in live cells has become a standard technique for evaluating protein distribution and function. Typically, expression levels of experimentally introduced proteins are not regulated, and high levels are often preferred to facilitate detection. However, overexpression of many proteins leads to mislocalization and pathologies. Therefore, for normative studies, moderate levels of expression may be more suitable. To understand better the dynamics of intermediate filament formation, transport, and stability in a healthy, living cell, we inserted neurofilament heavy chain (NFH)‐green fluorescent protein (GFP) fusion constructs in adenoviral vectors with tetracycline (tet)‐regulated promoters. This system allows for turning on or off the synthesis of NFH‐GFP at a selected time, for a defined period, in a dose‐dependent manner. We used this inducible system for live cell imaging of changes in filament structure and cell shape, motility, and transport associated with increasing NFH‐GFP expression. Cells with low to intermediate levels of NFH‐GFP were structurally and functionally similar to neighboring, nonexpressing cells. In contrast, overexpression led to pathological alterations in both filament organization and cell function. © 2002 Wiley‐Liss, Inc.
Activation of the peroxisome proliferator‐activated receptor‐α enhances cell death in cultured cerebellar granule cells
Authors: Smith Steven A. , May Fiona J. , Monteith Gregory R. , Roberts‐Thomson Sarah J.
Published: August 2002

Peroxisome proliferator‐activated receptor‐α (PPARα) is a member of the steroid hormone receptor superfamily. In rodents, PPARα alters genes involved in cell cycle regulation in hepatocytes. Some of these genes are implicated in neuronal cell death. Therefore, in this study, we examined the toxicological consequence of PPARα activation in rat primary cultures of cerebellar granule neurons. Our studies demonstrated the presence of PPARα mRNA in cultures by reverse transcriptase‐polymerase chain reaction. After 10 days in vitro, cerebellar granule neuron cultures were incubated with the selective PPARα activator 4‐chloro‐6‐(2,3‐xylidino)2‐pyrimidinylthioacetic acid (Wy‐14,643). The inherent toxicity of Wy‐14,643 and the effect of PPARα activation following toxic stimuli were assessed. In these studies, neurotoxicity was induced through reduction of extracellular [KCl] from 25 mM to 5.36 mM. We observed no inherent toxicity of Wy‐14,643 (24 hr) in cultured cerebellar granule cells. However, after reduction of [KCl], cerebellar granule cell cultures incubated with Wy‐14,643 showed significantly greater toxicity than controls. These results suggest a posssible role for PPARα in augmentation of cerebellar granule neuronal death after toxic stimuli. J. Neurosci. Res. 66:236–241, 2001. © 2001 Wiley‐Liss, Inc.
Brain drain in declining organizations: toward a research agenda
Authors: Rosenblatt Zehava , Sheaffer Zachary
Published: August 2002

Brain drain (BD) is one of the more detrimental implications of organizational decline and crisis, yet it has only been fleetingly addressed in organization studies. In light of this lacuna, the current paper introduces a conceptual framework of BD during decline. A model featuring both BD antecedents (predictors) and consequences is presented, including an analysis of leavers' behavioral characteristics. The paper offers a set of research propositions and concludes with directions for future study. Copyright © 2001 John Wiley & Sons, Ltd.
Calculation of direct solar and diffuse radiation in Israel
Authors: Becker Stefan
Published: August 2002

This study deals with the calculation of direct solar radiation and diffuse radiation for locations in Israel as hourly values. The model is based on the calculation of the Linke turbidity factors for the stations Bet‐Dagan, Jerusalem, Beer Sheva, Sedom and Eilat, which have been determined from radiation measurements. The turbidity factors for clear sky conditions showed a characteristic yearly pattern and the differences between the stations were related to their geographical locations. The model requires different algorithms for calculations in the Rift Valley system and the rest of Israel. The calculations proved to be very accurate for clear sky conditions with high radiation values (average deviation: 7.3% or 61.6 W/m2 for values above 600 W/m2). The presence of clouds and lower sun angles lead to less accurate results, which are nevertheless still acceptable within the range for further applications. Copyright © 2001 Royal Meteorological Society
Patterns of convection in the tropical pacific and their influence on New Zealand weather
Authors: Kidson John W. , Renwick James A.
Published: August 2002

Characteristic patterns of convection in the tropical Pacific Ocean have previously been inferred from analysis of outgoing longwave radiation (OLR), and associated with year‐to‐year variations in El Niño (EN)–Southern Oscillation events. This study examines both the effects of these convection patterns on the New Zealand climate, and the more general influence of tropical convection on the New Zealand sector of the Southern Hemisphere.

The Southern Hemisphere circulation, as a whole, is found to be most strongly influenced by equatorial convection near the Philippines, and in a broad band over the central Pacific. Where increased convection occurs west of 160°E, La Niña‐like (LN) conditions prevail. When the anomalous convective activity is located near the dateline, in ‘moderate’ EN conditions, SW flow prevails over New Zealand. This gives way to stronger WSW anomalies as the centre of convection is displaced further eastwards and a second centre of reduced convection becomes prominent west of the dateline in strong EN (EN+) events.

The changes in wind regimes over the New Zealand region implied by the hemispheric 1000 hPa height fields are supported by mean sea‐level pressure differences between a number of New Zealand and adjacent island stations. Indices of the zonal flow show a weak reduction in strength of the westerlies for LN OLR composites, and no apparent effects for EN composites, whereas EN+ conditions strongly favour above‐normal westerlies. The meridional flow over New Zealand is skewed towards more frequent southerlies in both the EN and EN+ composites, whereas LN conditions favour northerly flow anomalies.

A change is also observed in the frequency of New Zealand‐area ‘weather regimes’. Enhanced convection centred on 5°S and east of the dateline, as found in the EN+ composites, leads to an increase in zonal regimes and a corresponding decrease in blocking regimes. The direct influence of tropical OLR variations on New Zealand temperature and precipitation has also been assessed. These indicate that the response is not simply one of degree. Different spatial anomaly patterns in the climatic elements result from the varying regional circulation patterns, and these need to be considered if present climate‐forecasting schemes are to be improved. Copyright © 2002 Royal Meteorological Society.
Status of theoretical modeling of tautomerization in free-base porphyrin
Authors: MAITY DILIP K. , TRUONG THANH N.
Published: August 2002

We provide a review on the status of theoretical modeling of tautomerization in free-base porphyrin. We focus our discussion on several aspects, namely: (1) potential surfaces for both the stepwise and concerted mechanisms calculated at different levels of theory, (2) solvent effects and (3) kinetics. The importance of quantum mechanical tunneling in this double hydrogen atoms transfer process is analyzed.
Transient resonance Raman spectroscopic and ab initio MO investigation of substituent effects on the T1 triplet states of halobiphenyls
Authors: Lee Cheong Wan , Pan Duohai , Shoute Lian C. T. , Phillips David Lee
Published: August 2002

Nanosecond transient resonance Raman spectra of the T1 states and Raman spectra of the S0 states of nine halogenated biphenyl compounds were obtained and ab initio computations were performed to determine the optimized geometry and vibrational wavenumbers of the T1 and S0 states of 10 halogenated biphenyl compounds. Substitution of halogen atoms at meta or para positions relative to the interring C—C bond leads to little change in the structure of the halogenated biphenyl compounds relative to the corresponding S0 and T1 states of biphenyl. Substitution of halogen atoms at ortho positions results in significant increases in the twisting between the two phenyl rings of the S0 and T1 states of the halogenated biphenyl compounds relative to the S0 and T1 states of biphenyl. The degree of twisting between the two phenyl rings in ortho‐substituted halogenated biphenyls appears to depend on the steric, electronegativity and/or polarizability properties of the halogen atom. Copyright © 2001 John Wiley & Sons, Ltd.
Fluorescence suppression in resonance Raman spectroscopy using a high‐performance picosecond Kerr gate
Authors: Matousek P. , Towrie M. , Ma C. , Kwok W. M. , Phillips D. , Toner W. T. , Parker A. W.
Published: August 2002

A high‐performance Kerr gate designed for the suppression of fluorescence in both time‐resolved and steady‐state resonance Raman spectroscopy is described and its performance illustrated. This is an improved version of a system described recently, with superior extinction ratio, higher throughput and wider usable spectral range. Specially designed polarizers are an essential feature of the system. The gate opens for ∼4 ps at 1 kHz repetition rate, throughput in the open state is up to ∼40% (excluding Fresnel losses on optical elements), the extinction ratio in the closed state is 10−5 and the usable spectral range is 300–700 nm with a single set of polarizers. The Kerr gate is driven by ∼500 µJ, 1 kHz, 1 ps laser pulses at 800 nm and we believe that it is currently the most powerful device in operation for the temporal rejection of fluorescence from Raman spectra. It increases the general applicability of Raman spectroscopy as illustrated by picosecond time‐resolved resonance Raman spectra of the intramolecular charge transfer state of 4‐dimethylaminobenzonitrile and by the ground‐state Raman spectrum of unleaded petrol at 400 nm probe wavelength. Copyright © 2001 John Wiley & Sons, Ltd.
Raman scattering study of liquid ethylene glycol confined to nanoporous silica glasses
Authors: Luo Ren‐Sheng , Jonas Jiri
Published: August 2002

The Raman spectra of liquid ethylene glycol (EG) and EG confined to series of nanoporous silica glasses with pores ranging from 30.7 to 68.5 Å were recorded at 303 K. Using vibrational assignments of specific Raman bands to the trans and gauche conformers of EG allowed us to follow the effect of confinement on the equilibrium of these conformers. With decreasing pore size an increase in the trans conformer fraction was observed. This increase in the trans conformer fraction can be related to the hydrogen bonding of EG molecules to pore surface silanol groups of the silica glasses. In surface modified glasses where the silanol groups were replaced by more hydrophobic—O—Si—(CH3)3 groups the trans/gauche ratio does not change with increasing confinement, thus providing evidence for the dominant role of the hydrogen bonding ability of silanols in non‐modified glasses to change the conformer equilibrium. The plot of the fraction of the trans conformer Ft as a function of the reciprocal of the pore radius 1/R showed good linearity. This indicates that the two‐state exchange model can be applied to the analysis of the Raman data allowing the determination of the fraction of the trans conformer in the surface layer liquid. Assuming a surface layer thickness of one molecular diameter of EG one determines Ft≈0.97 in the surface layer liquid. Copyright © 2001 John Wiley & Sons, Ltd.
Soft tissue sarcomas involving the pelvis
Authors: Lewis S. J. , Wunder J. S. , Couture J. , Davis M. , Catton C. , Kandel R. A. , Kotwall C. , O'Sullivan B. , Bell R. S.
Published: August 2002

Background and Objectives:

Soft tissue sarcomas (STS) of the true pelvis are rare tumors and there is little information in the literature related to pelvic STS. The purposes of this review were to understand the anatomic extension of these tumors to better plan surgical treatment and to determine the outcome of these patients.

Methods:

Eighteen consecutive patients presenting between 1987 and 1995 with soft tissue sarcomas involving the true pelvis were retrospectively reviewed at minimum follow‐up of 18 months. Cross‐sectional imaging was reviewed for each patient to determine the anatomical location of the lesions.

Results:

The tumors were confined to the true pelvis in 4 patients, extended to the retroperitoneum in three cases, and extended to the thigh in 11 patients. Adjuvant radiation was administered to all but 2 patients who had received radiation to the region in the past and all patients underwent surgical resection (local resection in 13 patients and hindquarter amputation in 5 patients). Surgical resection had a high rate of morbidity and complications including positive resection margins in nine individuals. Of the 18 patients, 11 died at a mean time of 15.5 (2–58) months from surgery, 4 were alive with evidence of disease at a mean time of 44.3 (18–68) months, and 3 were alive with no evidence of disease at a mean time of 57 (43–71) months.

Conclusions:

Soft tissue sarcoma of the pelvis is fortunately a rare disease with a high risk of local and systemic disease progression despite treatment with irradiation and surgical resection. J. Surg. Oncol. 2001; 77:8–14. © 2001 Wiley‐Liss, Inc.
Lung cancer in patients younger than 40 years of age
Authors: Maruyama Riichiroh , Yoshino Ichiro , Yohena Tomofumi , Uehara Tadashi , Kanematsu Takanori , Kitajima Masachika , Teruya Takao , Ichinose Yukito
Published: August 2002

Background and Objectives

We investigated whether the clinicopathologic characteristics and prognosis of lung cancer in younger patients differ from those of older patients.

Methods

Among 2,763 lung cancer patients treated during the period from April of 1972 to April of 1997, we retrospectively investigated the clinical features and prognosis of 53 patients under 40 years of age (young group) and compared them with the findings of 1,886 patients with 60 years of age or older (elderly group).

Results

The proportion of female patients in the younger group was significantly higher than that in the elderly group (39.6% vs. 24.1%). The young group had a significantly higher proportion of adenocarcinoma (75.5% vs. 44.8%) and stage III‐IV disease (73.6% vs. 59.2%) and a significantly lower proportion of squamous cell carcinoma (3.8% vs. 32.1%). Regarding the selection of therapy, in the young group, a significantly lower proportion of patients underwent surgical therapy (35.8% vs. 41.5%) and a significantly higher proportion of those (37.7% vs. 16.4%) received chemotherapy. The overall survival between the young and elderly groups was not significantly different. Moreover, the 5‐year survival rate of the patients undergoing a surgical resection was 56.1% in the young group and 44.8% in the elderly group (P = 0.0615).

Conclusions

This study suggests that the prognosis of young patients with lung cancer is at least equivalent to that of older patients; therefore, they should be managed according to the general therapeutic guidelines. J. Surg. Oncol. 2001;77:208–212. © 2001 Wiley‐Liss, Inc.
Benzylmalonic acid reaction with iodine and behavior in a Briggs–Rauscher oscillator
Authors: Cervellati Rinaldo , Furrow Stanley D. , Pompeis Silvia De
Published: August 2002

Benzylmalonic acid (BzMA) reacts via an enol mechanism with aqueous iodine to form rather stable iodobenzylmalonic acid. In the presence of iodate, which oxidizes iodide to di‐iodine, the reaction goes to completion. The kinetics of the reaction BzMA + I2 + IO3− + H+ have been studied and the results were interpreted with a suitable mechanism. In a mixture with acidic iodate, hydrogen peroxide, and manganous ions, BzMA can serve as a substrate for a Briggs–Rauscher‐type oscillating reaction. The behavior of this oscillator has been studied in detail. A mechanistic interpretation of the oscillations based on a new kinetic model is also given. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 357–365, 2002
Editorial: Sense making in marketing organizations and consumer psychology: Theory and practice
Authors: Woodside Arch G.
Published: August 2002

Sense making includes both explicit and implicit mental processes of constructing, framing, creating, and rendering a view (e.g., an executive's mental model of “how things get done in my organization.” Related to decision making, sense making includes automatic and controlled scanning of memory and environments for framing issues. Sense making is meaning creation based on current and prior interpretations of thoughts generated from three sources: external stimuli, focused retrieval from internal memory, and seemingly random foci in working memory; such sense making is constructed on cultural pilings held unconsciously in long‐term memory. Consequently, meta‐sense‐making efforts are always incomplete; that is, all of us possess an incomplete ability to understand the process and outcomes of our own sense making. This P&M special issue includes five articles related by their focus on understanding how marketing executives and consumers go about sense making, as well as how sense‐making processes are transformed to result in new mental models of perceived realities. © 2001 John Wiley & Sons, Inc.
Symmetric coupling of finite and boundary elements for exterior magnetic field problems
Authors: Kuhn M. , Steinbach O.
Published: August 2002

We consider a coupled finite element (fe)–boundary element (be) approach for three‐dimensional magnetic field problems. The formulation is based on a vector potential in a bounded domain (fe) and a scalar potential in an unbounded domain (be). We describe a coupled variational problem yielding a unique solution where the constraints in the trial spaces are replaced by appropriate side conditions. Then we discuss a Galerkin discretization of the coupled problem and prove a quasi‐optimal error estimate. Finally we discuss an efficient preconditioned iterative solution strategy for the resulting linear system. Copyright © 2002 John Wiley & Sons, Ltd.
Calculation of resonant frequencies of LS higher order modes in a dielectrically loaded grooved waveguide
Authors: Che Wenquan , Ma Jin‐Ping , Yung Edward Kai‐Ning
Published: August 2002

A simple and efficient variation method is presented in this letter, which is employed to calculate the resonant frequencies of LS higher order modes in a dielectrically loaded grooved waveguide. Emphasis is placed on the calculation of the resonant frequencies of LSE11 and LSM11 modes since, certainly the first, and most probably the second will propagate in a practical device. The validity of this method is verified by experiments. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 442–446, 2001.
Polarization‐preserving reflected beam splitter
Authors: Habli Mohamad A.
Published: August 2002

The design of a polarization preserving reflected beam splitter (PPRBS) is presented. The PPRBS consists of a V‐shaped absorbing substrate coated with a single thin‐film layer. The PPRBS operates in the UV region. The power reflection coefficient ranges from 69 to 90% for angles of incidence ranging from 85 to 89°, respectively. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 484–487, 2001.
Combined chemotherapy and local treatment in the management of intraocular retinoblastoma
Authors: Brichard Bénédicte , De Bruycker Jean Jacques , De Potter Patrick , Neven Bénédicte , Vermylen Christiane , Cornu Guy
Published: August 2002

Background

To assess the efficacy of chemotherapy (chemoreduction) plus local treatments as an alternative to external beam and enucleation for intraocular retinoblastoma.

Materials and Methods

A prospective study was performed on 21 patients with retinoblastoma treated in our institution from September 1997 to December 2000 to study the ocular outcome of those 33 eyes.

Results

There were 9 unilateral and 12 bilateral retinoblastoma cases. There were 12 eyes with Reese‐Ellsworth group I–IV and 21 eyes with group V. Among 33 eyes, nine eyes (27%) were initially managed by enucleation. The remaining 24 eyes (73%) were initially treated with chemoreduction (maximum of six cycles of carboplatin, vincristine, etoposide) or chemothermotherapy. Among those 24 eyes, 20 were successfully treated with local treatments (thermotherapy plus cryotherapy in 16 eyes and thermotherapy plus cryotherapy plus 125I plaque radiotherapy in 4 eyes), enucleation eventually underwent in two eyes and was proposed but refused in one child with bilateral group V retinoblastoma. With a median follow‐up of 21 months, conservative management without external beam radiation was successful in all 12 eyes with group I–IV and in a total of 20/33 eyes (60%). Among the nine cases of unilateral retinoblastoma, eight were enucleated but among the 24 eyes with bilateral retinoblastoma, 19 (79%) were successfully treated with conservative therapy.

Conclusions

It may be possible to eradicate viable tumor in all eyes with Reese‐Ellsworth group I–IV retinoblastoma by chemoreduction followed by local treatments. Although 8 out of 21 eyes (38%) with group V retinoblastoma may be salvaged after chemoreduction and local therapies, enucleation remained the treatment of choice in those eyes with total retinal detachment and diffuse vitreous seeding. Med Pediatr Oncol 2002;38:411–415. © 2002 Wiley‐Liss, Inc.
Models of white matter injury: Comparison of infectious, hypoxic‐ischemic, and excitotoxic insults
Authors: Hagberg Henrik , Peebles Donald , Mallard Carina
Published: August 2002

White matter damage (WMD) in preterm neonates is strongly associated with adverse outcome. The etiology of white matter injury is not known but clinical data suggest that ischemia‐reperfusion and/or infection‐inflammation are important factors. Furthermore, antenatal infection seems to be an important risk factor for brain injury in term infants. In order to explore the pathophysiological mechanisms of WMD and to better understand how infectious agents may affect the vulnerability of the immature brain to injury, numerous novel animal models have been developed over the past decade. WMD can be induced by antenatal or postnatal administration of microbes (E. coli or Gardnerella vaginalis), virus (border disease virus) or bacterial products (lipopolysaccharide, LPS). Alternatively, various hypoperfusion paradigms or administration of excitatory amino acid receptor agonists (excitotoxicity models) can be used. Irrespective of which insult is utilized, the maturational age of the CNS and choice of species seem critical. Generally, lesions with similarity to human WMD, with respect to distribution and morphological characteristics, are easier to induce in gyrencephalic species (rabbits, dogs, cats and sheep) than in rodents. Recently, however, models have been developed in rats (PND 1–7), using either bilateral carotid occlusion or combined hypoxia‐ischemia, that produce predominantly white matter lesions. LPS is the infectious agent most often used to produce WMD in immature dogs, cats, or fetal sheep. The mechanism whereby LPS induces brain injury is not completely understood but involves activation of toll‐like receptor 4 on immune cells with initiation of a generalized inflammatory response resulting in systemic hypoglycemia, perturbation of coagulation, cerebral hypoperfusion, and activation of inflammatory cells in the CNS. LPS and umbilical cord occlusion both produce WMD with quite similar distribution in 65% gestational sheep. The morphological appearance is different, however, with a more pronounced infiltration of inflammatory cells into the brain and focal microglia/macrophage (“inflammatory WMD”) in response to LPS compared to hypoperfusion evoking a more diffuse microglial response usually devoid of cellular infiltrates (“ischemic WMD”). Furthermore, low doses of LPS that by themselves have no adverse effects in 7‐day‐old rats (maturation corresponding to the near term human fetus), dramatically increase brain injury to a subsequent hypoxic‐ischemic challenge, implicating that bacterial products can sensitize the immature CNS. Contrary to this finding, other bacterial agents like lipoteichoic acid were recently shown to induce tolerance of the immature brain suggesting that the innate immune system may respond differently to various ligands, which needs to be further explored. MRDD Research Reviews 2002;8:30–38. © 2002 Wiley‐Liss, Inc.
Juvenile onset Huntington's disease—clinical and research perspectives
Authors: Nance Martha A. , Myers Richard H.
Published: August 2002

Huntington's disease (HD) is an inherited neurodegenerative disorder. The mutation which causes the disease is an expansion in the number of repetitions of three nucleotides, C, A, and G in exon 1 of the huntingtin gene. The gene normally has 15 to 30 repeats and an expansion to 40 or more is associated with HD. HD usually has a mid‐life onset, but a juvenile form, defined by onset of symptoms before the age of 21 years, is present in about 7% of HD cases. Juvenile HD is characterized by (1) transmission from an HD affected father, (2) an unusually large repeat size, usually of 60 or more units, and (3) unique clinical features, including rigidity and seizure disorder. Although juvenile onset is associated with a more severe neuropathological involvement, the neuropathological characteristics of juvenile HD are similar to those seen in the adult form in that the striatum bears the brunt of the illness. Clumps of protein, termed inclusion bodies, which stain positive for huntingtin and ubiquitin, are found primarily in the nucleus but also in the cytoplasm and axons in HD neurons. Research suggests that these inclusion bodies sequester a deleterious protein fragment and prolong cell life during the degenerative process of the disease. MRDD Research Reviews 2001;7:153–157. © 2001 Wiley‐Liss, Inc.
Half‐Fourier single‐shot STEAM MRI
Authors: Finsterbusch Jürgen , Frahm Jens
Published: August 2002

As a high‐speed imaging technique based on stimulated echoes single‐shot STEAM MRI is insensitive to chemical shift artifacts and magnetic susceptibility differences. The achievable signal‐to‐noise ratio (SNR) is limited by the fact that high flip angles of the read‐out excitation pulses cause a steep decay of the stimulated echo train and therefore degrade the point‐spread function of the resulting image. The present work investigates the use of half‐Fourier phase encoding which weakens the flip angle constraint by reducing the number of necessary excitations. Single‐shot STEAM MRI of the normal human brain at 2.0 T demonstrates that half‐Fourier versions either reduce the measurement time by almost a factor of two without sacrificing the SNR or increase the SNR by about 40% while keeping the measurement time constant. Magn Reson Med 47:611–615, 2002. © 2002 Wiley‐Liss, Inc.
Determination of regional blood volume and intra‐extracapillary water exchange in human myocardium using Feruglose: First clinical results in patients with coronary artery disease
Authors: Wacker Christian M. , Wiesmann Frank , Bock Michael , Jakob Peter , Sandstede Jörn J.W. , Lehning Anja , Ertl Georg , Schad Lothar R. , Haase Axel , Bauer Wolfgang R.
Published: August 2002

The aim of this pilot study in humans was to investigate the effect of an intravascular contrast agent (CA) on relaxation rate in myocardium (R1,myo) in the steady state. The dependence of R1,myo on R1,blood was characterized and compared with a theoretical model which allowed determination of the intra‐ extracapillary water proton exchange frequency (f = 0.48 s−1) and the intracapillary blood volume (RBV = 12.9 %). A linear response range of ΔR1,myo on ΔR1,blood was estimated which in future studies will allow the determination of RBV with intravascular CA. Magn Reson Med 47:1013–1016, 2002. © 2002 Wiley‐Liss, Inc.
In vivo imaging of the neutron capture therapy agent BSH in mice using 10B MRI
Authors: Bendel Peter , Koudinova Natalia , Salomon Yoram
Published: August 2002

Boron neutron capture therapy (BNCT) is an experimental cancer treatment modality requiring the targeting of 10B‐enriched compounds to the tumor, which is then irradiated by low‐energy neutrons. One of the boron‐containing compounds used for this purpose is the mercaptoborane Na2B12H11SH (BSH). The first in vivo MR images of 10B‐enriched BSH are presented here. BSH, injected into the tail vein of mice with implanted M2R melanoma xenografts, was imaged using 3D gradient echo 10B MRI. 10B NMR spectroscopy, localized mainly to the tumor by virtue of the use of a small surface coil, was applied to measure the T1 (2.9 ± 0.3 ms) and T2 (1.75 ± 0.25 ms) values of the 10B signal. The MRI experiments detected levels of about 20 ppm (μg boron / g tissue) at 6 × 6 × 6 mm spatial resolution in a total scan time of 16 min. Magn Reson Med 46:13–17, 2001. © 2001 Wiley‐Liss, Inc.
Optimal dose of Gd‐DTPA in dynamic MR studies
Authors: Rusinek Henry , Lee Vivian S. , Johnson Glyn
Published: August 2002

The relationship between the administered dose d of Gd‐DTPA and the accuracy of measurements of the glomerular filtration rate G and the cardiac output O was investigated. For a wide range of values the concentration of Gd‐DTPA can be uniquely derived from MR signals and precontrast longitudinal relaxation time. Fixed and random errors in these measured variables were analyzed. Depending on noise level and the level of renal function, errors in G reach a minimum for d = 1.4–2.8 mmol. Random errors in G are relatively insensitive to d as long as d > 1.5 mmol. These results establish the feasibility of dynamic MR measurements using doses of Gd‐DTPA that are several times lower than current standards. Magn Reson Med 46:312–316, 2001. © 2001 Wiley‐Liss, Inc.
Stability analysis and design of automatic frequency control system for in vivo EPR spectroscopy
Authors: Hirata Hiroshi , Luo Zhi‐Wei
Published: August 2002

Stability analysis and design of an automatic frequency control (AFC) system for in vivo continuous‐wave EPR spectroscopy is described. The open‐loop function of the feedback control system for the AFC was derived and the stability of the feedback loop systematically examined. A stability analysis of the system is demonstrated and a systematic design procedure is proposed. The design is started from the required system specifications (phase margin, steady‐state error, and system bandwidth) and clear guidelines for designing an AFC system are given. A case study of the design is presented based on the specific needs of in vivo EPR measurements. A phase margin of 53°, a steady‐state error of 1.6%, and a system bandwidth of up to 1.8 kHz were obtained in the designed AFC system. The system specifications defined in advance are satisfied in this case study. Magn Reson Med 46:1209–1215, 2001. © 2001 Wiley‐Liss, Inc.
Effects of experimental muscle pain on electromyographic activity of masticatory muscles in the rat
Authors: Ro Jin Y. , Svensson Peter , Capra Norman
Published: August 2002

The aim of the present study was to investigate the effects of noxious chemical stimulation of a jaw muscle on postural electromyographic (EMG) activity from several masticatory muscles in lightly anesthetized rats. Unilateral injection of a substance known to induce acute muscle pain (5% NaCl) or longer duration of pain with inflammation (mustard oil) was made into the masseter muscle. The changes in EMG activity following the injection were recorded from the injected and contralateral masseter muscles and the ipsilateral digastric muscle. The algesic chemicals produced a significant but transient increase in EMG activity in all three muscles. The data from the present study and similar observations from clinical and experimental human studies suggest that increased activity from muscle nociceptors is not sufficient to produce a prolonged increase in postural EMG activity. Therefore, the development and maintenance of chronic jaw muscle pain does not appear to result from a feedback cycle mechanism. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Dendritic reorganization in pyramidal neurons in medial prefrontal cortex after chronic corticosterone administration
Authors: Wellman Cara L.
Published: August 2002

Chronic stress produces deficits in cognition accompanied by alterations in neural chemistry and morphology. For example, both stress and chronic administration of corticosterone produce dendritic atrophy in hippocampal neurons (Woolley C, Gould E, McEwen BS. 1990. Exposure to excess glucocorticoids alters dendritic morphology of adult hippocampal pyramidal neurons. Brain Res 531:225–231; Watanabe Y, Gould E, McEwen BS, 1992b. Stress induces atrophy of apical dendrites of hippocampal CA3 pyramidal neurons. Brain Res 588:341–345). Prefrontal cortex is also a target for glucocorticoids involved in the stress response (Meaney MJ, Aitken DH. 1985. [3H]Dexamethasone binding in rat frontal cortex. Brain Res 328:176–180); it shows neurochemical changes in response to stress (e.g., Luine VN, Spencer RL, McEwen BS. 1993. Effect of chronic corticosterone ingestion on spatial memory performance and hippocampal serotonergic function. Brain Res 616:55–70; Crayton JW, Joshi I, Gulati A, Arora RC, Wolf WA. 1996. Effect of corticosterone on serotonin and catecholamine receptors and uptake sites in rat frontal cortex. Brain Res 728:260–262; Takao K, Nagatani T, Kitamura Y, Yamawaki S. 1997. Effects of corticosterone on 5‐HT1Aand 5‐HT2receptor binding and on the receptor‐mediated behavioral responses of rats. Eur J Pharmacol 333:123–128; Sandi C, Loscertales M. 1999. Opposite effects on NCAM expression in the rat frontal cortex induced by acute vs. chronic corticosterone treatments. Brain Res 828:127–134), and mediates many of the behaviors that are altered by chronic corticosterone administration (e.g., Lyons DM, Lopez JM, Yang C, Schatzberg AF. 2000. Stress‐level cortisol treatment impairs inhibitory control of behavior in monkeys. J Neurosci 20:7816–7821). To determine if glucocorticoid‐induced morphological changes also occur in medial prefrontal cortex, the effects of chronic corticosterone administration on dendritic morphology in this corticolimbic structure were assessed. Adult male rats received s.c. injections of either corticosterone (10 mg in 250 μL sesame oil;n= 8) or vehicle (250 μL;n= 8) daily for 3 weeks. A third group of rats served as intact controls (n= 4). Brains were stained using a Golgi‐Cox procedure and pyramidal neurons in layer II‐III of medial prefrontal cortex were drawn; dendritic morphology was quantified in three dimensions. Sholl analyses demonstrated a significant redistribution of apical dendrites in corticosterone‐treated animals: the amount of dendritic material proximal to the soma was increased relative to intact rats, while distal dendritic material was decreased relative to intact animals. Thus, chronic glucocorticoid administration dramatically reorganized apical arbors in medial prefrontal cortex. This reorganization likely reflects functional changes and may contribute to stress‐induced changes in cognition. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 245–253, 2001
Essential oils from micropropagated plants of Lavandula viridis
Authors: Nogueira J. M. F. , Romano A.
Published: August 2002

The essential oils of Lavandula viridis were analysed by GC and GC‐MS. Comparisons were made between three types of plant material from the same clone: field‐grown plant, in vitro shoot cultures and micropropagated plants of the same clone. The most common components usually found in lavender oils were present in the oil samples analysed and more than 45 constituents were identified, representing more than 80% of the essential oil. The essential oils analysed consisted mainly of monoterpenes (75.4–76.3%), where oxygenated and hydrocarbons identified ranged from 41.8 to 57.3% and 18.1 to 34.2%, respectively. The major components found were 1.8‐cineole (18.2–25.1%), camphor (9.1–15.7%), α‐pinene (8.8–14.1%), borneol (4.1–4.8%), β‐pinene (1.2–5.6%), Δ3‐carene (1.0–6.5%) and α‐terpineol (0.8–4.2%). The monoterpene fraction of the in vitro shoot cultures showed different relative amounts of hydrocarbons and oxygenated components in relation to the parent plant and to micropropagated plants. In the sesquiterpene hydrocarbon fraction of the oil samples analysed (6.1–8.2%), 7‐epi‐α‐selinene (1.6–4.8%) was the most important component and the oxygenated sesquiterpenes were found in small amounts (1.1–1.7%). The essential oils from field‐grown plants of L. viridis, when compared with those obtained from in vitro shoot cultures or micropropagated plants of the same clone, demonstrated that the same major components were found without significant compositional variations. Copyright © 2001 John Wiley & Sons, Ltd.
Cytogenetic analysis of trophoblasts by comparative genomic hybridization in embryo‐fetal development anomalies
Authors: Tabet A. C. , Aboura A. , Dauge M. C. , Audibert F. , Coulomb A. , Batallan A. , Couturier‐Turpin M. H. , Feldmann G. , Tachdjian G.
Published: August 2002

Cytogenetic studies of spontaneous abortions or intrauterine fetal death depend on conventional tissue culturing and karyotyping. This technique has limitations such as culture failure and selective growth of maternal cells. Fluorescent in situ hybridization (FISH) using specific probes permits diagnosis of aneuploidies but is limited to one or a few chromosomal regions. Comparative genomic hybridization (CGH) provides an overview of chromosomal gains and losses in a single hybridization directly from DNA samples. In a prospective study, we analyzed by CGH trophoblast cells from 21 fetuses in cases of spontaneous abortions, intrauterine fetal death or polymalformed syndrome. Six numerical chromosomal abnormalities including one trisomy 7, one trisomy 10, three trisomies 18, one trisomy 21 and one monosomy X have been correctly identified by CGH. One structural abnormality of the long arm of chromosome 1 has been characterized by CGH. One triploidy and two balanced pericentromeric inversions of chromosome 9 have not been identified by CGH. Sexual chromosomal constitutions were concordant by both classical cytogenetic technique and CGH. Contribution of trophoblast analysis by CGH in embryo‐fetal development anomalies is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Denaturing high‐performance liquid chromatography (DHPLC)‐based prenatal diagnosis for tuberous sclerosis
Authors: Bénit Paule , Bonnefont Jean‐Paul , Kara Mostefa Ali , Francannet Christine , Munnich Arnold , Ray Pierre F.
Published: August 2002

Tuberous sclerosis (TSC) is a frequent autosomal‐dominant condition (affecting 1 in 6000 individuals) caused by various mutations in either the hamartin (TSC1) or the tuberin gene (TSC2). This allelic and non‐allelic heterogeneity makes genetic counseling and prenatal diagnosis difficult, especially as a significant proportion of TSC cases are due to de novo mutations. For this reason the identification of the disease causing mutation is mandatory for accurate counseling, yet current mutation detection methods such as single‐strand conformation polymorphism (SSCP) or denaturing gradient gel electrophoresis (DGGE) are labor intensive with limited detection efficiency. Denaturing high‐performance liquid chromatography (DHPLC) is a high‐throughput, semi‐automated mutation detection system with a reported mutation detection rate close to 100% for PCR fragments of up to 800 bp. We used a recently described DHPLC assay allowing the efficient detection of mutations in TSC1 to analyze the DNA extracted from a chorion villus sample in order to perform a prenatal diagnosis for TSC. The fetus was found not to have inherited the deleterious mutation and the DHPLC diagnosis was confirmed by haplotype analysis. This represents the first DHPLC‐based prenatal diagnosis of a genetic disease. Copyright © 2001 John Wiley & Sons, Ltd.
Solution properties of hyperbranched polymers and synthetic application for amphiphilic star‐hyperbranched copolymers by grafting from hyperbranched macroinitiator
Authors: Ishizu Koji , Mori Akihide
Published: August 2002

Hyperbranched polystyrenes (PS) were prepared by living radical photopolymerization of N,N‐diethyldithiocarbamoylmethylstyrene (DTCS) as an inimer under UV irradiation. Branched PS with an average chain length between branching points of four styrene units was also prepared by living radical copolymerization of DTCS with styrene. The ratio of radius of gyration to hydrodynamic radius RG/RH for these hyperbranched polymers was in the range 0.82–0.89 in toluene. The translational diffusion coefficient D(C) showed a constant value in the range of 0–14 × 10−3 g ml−1 in toluene. It was found from these dilute solution properties that hyperbranched PSs formed a unimolecular structure even in a good solvent because of their compact nature. These hyperbranched PSs exhibited large amounts of photofunctional carbamate (DC) groups on their outside surfaces. Subsequently, we derived amphiphilic star‐hyperbranched copolymers by grafting from hyperbranched macroinitiator with 1‐vinyl‐2‐pyrrolidinone. These star‐hyperbranched copolymers were soluble in water and methanol.

© 2001 Society of Chemical Industry
A new type of imine α‐anion derived from 3‐methyl‐4‐phenyl‐1,2,5‐thiadiazole 1,1‐dioxide. Tautomerization and dimerization reactions
Authors: Aimone Silvia L. , Caram José A. , Mirífico María V. , Vasini Enrique J.
Published: August 2002

Proton abstraction from 3‐methyl‐4‐phenyl‐1,2,5‐thiadiazole 1,1‐dioxide (1b) in basic non‐aqueous media generated a resonance‐stabilized anion (1b−) that added to 1b producing a dimer, 3‐phenyl‐4‐(4‐phenyl‐3‐methylene‐1,2,5‐thiadiazolin‐2‐yl 1,1‐dioxide)‐4‐methyl‐1,2,5‐thiadiazoline 1,1‐dioxide (2). The anion and the dimer were also electrochemically generated by the cathodic reduction of 1b in acetonitrile solution. The neutralization of basic ethanolic solutions containing 1b− caused the precipitation of the tautomer of 1b, 3‐phenyl‐4‐methylene‐1,2,5‐thiadiazoline 1,1‐dioxide (3). The anion 1b−, and the new compounds 2 and 3 were characterized and identified by NMR, IR and UV–VIS spectroscopic techniques. Their voltammetric behavior was also investigated. Copyright © 2001 John Wiley & Sons, Ltd.
Controlled polymerization of acrylic acid under 60Co irradiation in the presence of dibenzyl trithiocarbonate
Authors: Hong Chun‐Yan , You Ye‐Zi , Bai Ru‐Ke , Pan Cai‐Yuan , Borjihan Gereltu
Published: August 2002

The polymerization of acrylic acid (AA) was performed under 60Co irradiation in the presence of dibenzyl trithiocarbonate at room temperature, and well‐defined poly(acrylic acid) (PAA) with a low polydispersity index was successfully prepared. The gel permeation chromatographic and 1H NMR data showed that this polymerization displays living free‐radical polymerization characteristics: a narrow molecular weight distribution (Mw/Mn = 1.07–1.22), controlled molecular weight, and constant chain‐radical concentration during the polymerization. Using PAAS C(S)SPAA as an initiator, the extension reaction of PAA with fresh AA was carried out under 60Co irradiation, and the results indicated that this extension polymerization displayed controlled polymerization behavior. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3934–3939, 2001