bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative patterns of postcranial ontogeny in therian Mammals: An analysis of relative timing of ossification events
Authors: SÁnchez‐villagra Marcelo R.
Published: October 2002

Data on the relative sequence of ossification of postcranial elements for eight therian mammals (Myotis lucifugus, Homo sapiens, Rattus norvegicus, Mus musculus, Mesocricetus auratus, Cavia porcellus, Didelphis albiventris, and Sminthopsis macroura) and three outgroups (Chelydra serpentina, Alligator mississippiensis, and Lacerta vivipara) were taken from the literature. For each species, a matrix was constructed in which the relative timing of the onset of ossification in 24 elements was summarized. This resulted in 276 event pairs (characters) for each species. Thirty‐three (33.3)% of the characters examined are uniform across all taxa, 16.3% are variable but uninformative in the phylogeny, and 50.4% potentially deliver diagnostic features for clades of two or more taxa. In all species examined, the clavicle is the first bone to appear. Placentalia is not unequivocally diagnosed by the state of any event pair, while Marsupialia has the largest amount of autapomorphies with 18. The acceleration in the timing of ossification of the scapula in relation to the hindlimb in marsupials is most probably causally correlated to movements after birth and during early phases of pre‐weaning life. Marsupials are almost unique among amniotes in that the earliest onset of ossification of at least one element among carpals and among tarsals is simultaneous. Three parsimony analyses, each one with a different reptilian taxon as outgroup, were performed using event pairs as characters. In all cases, results were incongruent with the phylogeny of the studied taxa. J. Exp. Zool. (Mol. Dev. Evol.) 294:264–273, 2002. © 2002 Wiley‐Liss, Inc.
Note on the path‐matching formula
Authors: Frank András , Szegő László
Published: October 2002

As a common generalization of matchings and matroid intersections, W.H. Cunningham and J.F. Geelen introduced the notion of path‐matchings. They proved a min‐max formula for the maximum value. Here, we exhibit a simplified version of their min‐max theorem and provide a purely combinatorial proof. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 110–119, 2002
Fabricational morphology of oblique ribs in bivalves
Authors: Checa Antonio G.
Published: October 2002

The formation of oblique ribs of bivalve shells usually has been attributed to processes of reaction‐diffusion of morphogens from cell to cell at the mantle margin or neural activation and lateral inhibition in the mantle. In particular, such ribs appear with high rates of lateral diffusion. Nevertheless, theoretical models fail to explain either partially or wholly some varieties of oblique ribs. After surveying the modes of formation of the shell and oblique ribs by the bivalve mantle and associated fabricational defects, I have determined that the mantle is able to develop an elaborate behavior in order to displace the rib in a particular direction during growth. The mantle margin is, therefore, not only the shell‐secreting organ, but also the main morphogenetic unit. In particular, there are two main fabricational strategies. In forms with strict contact guidance (SCG) the mantle is able to project far enough beyond the shell margins so as to feel the already formed reliefs and to align new growth increments of the ribs in the appropriate directions. The shell margin is always strongly reflected. In bivalves with reduced contact guidance plus constant lateral shift (RCG), the margin is usually acute and the information about ribs available to the mantle is reduced. During rib construction the mantle extrudes slightly from the shell edge and then pushes laterally by muscular action; in this way, the new growth increment of the rib is displaced laterally on a small scale. The contact‐guidance model is supported also by the homogeneous structure of the shell‐secreting mantle. From the morphogenetic standpoint, oblique ribs are related to commarginal ones and both differ completely from other ribbing patterns of bivalves. J. Morphol. 254:195–209, 2002. © 2002 Wiley‐Liss, Inc.
Magnetic resonance histology for morphologic phenotyping
Authors: Johnson G. Allan , Cofer Gary P. , Fubara Boma , Gewalt Sally L. , Hedlund Laurence W. , Maronpot Robert R.
Published: October 2002

Magnetic resonance histology (MRH) images of the whole mouse have been acquired at 100‐micron isotropic resolution at 2.0T with image arrays of 256 × 256 × 1024. Higher resolution (50 × 50 × 50 microns) of limited volumes has been acquired at 7.1T with image arrays of 512 × 512 × 512. Even higher resolution images (20 × 20 × 20 microns) of isolated organs have been acquired at 9.4T. The volume resolution represents an increase of 625,000× over conventional clinical MRI. The technological basis is summarized that will allow basic scientists to begin using MRH as a routine method for morphologcic phenotyping of the mouse. MRH promises four unique attributes over conventional histology: 1) MRH is non‐destructive; 2) MRH exploits the unique contrast mechanisms that have made MRI so successful clinically; 3) MRH is 3‐dimensional; and 4) the data are inherently digital. We demonstrate the utility in morphologic phenotyping a whole C57BL/6J mouse. J. Magn. Reson. Imaging 2002;16:423–429. Published 2002 Wiley‐Liss, Inc.
1H and 31P spectroscopy and bioenergetics in the lateralization of seizures in temporal lobe epilepsy
Authors: Hetherington Hoby P. , Pan Jullie W. , Spencer Dennis D.
Published: October 2002

Over the past decade, 1H and 31P spectroscopy measurements have demonstrated that significant metabolic alterations occur in temporal lobe epilepsy. However, to most accurately interpret these changes, metabolic heterogeneity and differences between gray and white matter must be accounted for. These alterations, decreased NAA and the ratio of phosphocreatine/inorganic phosphate, can be reversed with successful treatment of seizures. The reversibility of these two measures is consistent with the localization of NAA synthesis to neuronal mitochondria and the important role for bioenergetics in the pathophysiology of temporal lobe epilepsy. J. Magn. Reson. Imaging 2002;16:477–483. © 2002 Wiley‐Liss, Inc.
Screening and diagnosis of β‐ureidopropionase deficiency by gas chromatographic/mass spectrometric analysis of urine
Authors: Ohse Morimasa , Matsuo Masafumi , Ishida Akihito , Kuhara Tomiko
Published: October 2002

Dihydropyrimidine dehydrogenase (DHPDase), dihydropyrimidinase (DHPase) and β‐ureidopropionase (βUPase) are the enzymes that catalyze the first, second, and third steps of the degradation of pyrimidines, respectively. β‐Ureidopropionate (βUP) and β‐ureidoisobutyrate (βUIB) are increased in the urine of patients with βUPase deficiency. The original case in which βUPase deficiency was discovered by NMR spectroscopy was an 11‐month‐old patient who presented with hypotonia and dystonic movement. We detected a second but asymptomatic case during a pilot study of neonatal screening with filter‐paper urine, urease pretreatment and gas chromatography/mass spectrometry (GC/MS). The urease pretreatment of urine without fractionation resulted in a high recovery of these polar ureide compounds and allowed the highly sensitive GC/MS detection and diagnosis of βUPase deficiency. βUP and βUIB were identified using GC/MS techniques. In the urine of the neonate with βUPase deficiency, βUP and βUIB were persistently increased. Thymine, 5,6‐dihydrothymine and 5,6‐dihydrouracil were increased only moderately but significantly. It is known that thymine and uracil increase markedly in DHPDase deficiency, and 5,6‐dihydrothymine and 5,6‐dihydrouracil increase in DHPase deficiency. Therefore, βUPase deficiency can be differentially diagnosed from the first and second enzyme deficiencies. Application of this specific and sensitive diagnostic procedure will lead to an understanding of the clinical heterogeneity of βUPase deficiency. Furthermore, the identification of patients with defects in pyrimidine metabolism will enable doctors to avoid cancer chemotherapy with pyrimidine analogues such as 5‐fluorouracil, which could be dangerous for these patients. Copyright © 2002 John Wiley & Sons, Ltd.
Maturation‐dependent neurotoxicity of lead acetate in vitro: Implication of glial reactions
Authors: Zurich Marie‐Gabrielle , Eskes Chantra , Honegger Paul , Bérode Michèle , Monnet‐Tschudi Florianne
Published: October 2002

Despite a wealth of data on the neurotoxic effects of lead at the cellular and molecular levels, the reasons for its development‐dependent neurotoxicity are still unclear. Here, the maturation‐dependent effects of lead acetate were analyzed in immature and differentiated brain cells cultured in aggregates. Markers of general cytotoxicity as well as cell‐type‐specific markers of glial and neuronal cells showed that immature brain cells were more sensitive to lead than the differentiated counterparts, demonstrating that the development‐dependent neurotoxicity of lead can be reproduced in aggregating brain cell cultures. After 10 days of treatment, astrocytes were found to be more affected by lead acetate than neurons in immature cultures, and microglial cells were strongly activated. Eleven days after cessation of the treatment, lead acetate caused a partial loss of astrocytes and an intense reactivity of the remaining ones. Furthermore, microglial cells expressed a macrophagic phenotype, and the loss of activity of neuron‐specific enzymes was aggravated. In differentiated cultures, no reactive gliosis was found. It is hypothetized that the intense glial reactions (microgliosis and astrogliosis) observed in immature cultures contribute to the development‐dependent neurotoxicity of lead. © 2002 Wiley‐Liss, Inc.
Functional reconnections established by central respiratory neurons regenerating axons into a nerve graft bridging the respiratory centers to the cervical spinal cord
Authors: Gauthier P. , Réga P. , Lammari‐Barreault N. , Polentes J.
Published: October 2002

The present work investigated, in adult rats, the long‐term functional properties and terminal reconnections of central respiratory neurons regenerating axons within a peripheral nerve autograft bridging two separated central structures. A nerve graft was first inserted into the left medulla oblongata, in which the respiratory centers are located. Three months later, a C3 left hemisection was performed, and the distal tip of the graft was implanted into the C4 left spinal cord at the level of the phrenic nucleus, a natural central inspiratory target. Six to eight months after medullary implantation, the animals (n = 12) were electrophysiologically investigated to test 1) the phrenic target reinnervation by analyzing the phrenic responses elicited by bridge electrical stimulation and 2) the bridge innervation by unitary recordings of the spontaneous activity of regenerated axons within the nerve bridge. In the control group (n = 6), the medullary site of implantation corresponded to the dorsolateral medulla, a region known to be an unsuitable site for inducing respiratory axonal regrowth after nerve grafting. Stimulation of the nerve bridge never elicited phrenic nerve response, and no respiratory units were found within the nerve bridge. In the experimental group (n = 6), the proximal tip of the nerve bridge was implanted within the ventrolateral medulla at the level of the respiratory centers. Electrical stimulation of the nerve bridge induced phrenic nerve responses that reflected a postsynaptic activation of the phrenic target. Subsequent unitary recordings from teased fibers within the bridge revealed the presence of regenerated inspiratory fibers exhibiting discharge patterns typical of medullary inspiratory neurons, which normally make synaptic contacts with the inspiratory phrenic target. These results indicate that, when provided with an appropriate denervated target, central respiratory neurons with regenerated axons along a nerve bridge can remain functional for a long period and can make precise and specific functional reconnections with central homotypic target neurons. © 2002 Wiley‐Liss, Inc.
Chondroitin and keratan sulfates have opposing effects on attachment and outgrowth of ventral mesencephalic explants in culture
Authors: Macé K. , Saxod R. , Feuerstein C. , Sadoul R. , Hemming F.J.
Published: October 2002

During rat brain development, striatal proteoglycan (PG) expression shows specific spatio‐temporal modifications suggesting a possible role in the guidance of its dopaminergic afferents. The effects of individual glycosaminoglycans (GAGs) on dopaminergic (DA) neuronal adhesion and outgrowth were therefore studied. We tested the behavior of dissociated embryonic rat mesencephalic cells cultivated on substrate‐bound GAGs. Neuronal attachment was very limited and quantitative morphometry revealed variations in DA fiber outgrowth depending on the type and the concentration of GAG used. Next, we developed a cryoculture system to examine how neurons react toward GAGs expressed in situ. Rat brain slices from different developmental stages were used as substrates for embryonic mesencephalic explants. Preferential regions of adherence and outgrowth were observed: the striatum was found to be the most permissive, whereas the cortex was inhibitory. Western blotting experiments confirmed quantitative and qualitative changes in chondroitin sulfate (neurocan, phosphacan) and keratan sulfate (KS) containing PGs in these substrates and enzymatic digestion of GAGs before cryoculture revealed a substantial involvement of PGs in DA neuron adhesion and outgrowth. In particular, CSPGs seemed to mediate the permissive effect of the striatum, whereas KS confers an inhibitory effect to the cortex. PGs may thus be important for limiting midbrain projections to the striatum during development and for maintaining topography in the adult. © 2002 Wiley‐Liss, Inc.
Protein tyrosine phosphatase σ‐deficient mice show aberrant cytoarchitecture and structural abnormalities in the central nervous system
Authors: Meathrel Karen , Adamek Tamara , Batt Jane , Rotin Daniela , Doering Laurie C.
Published: October 2002

Protein tyrosine phosphatase σ (PTPσ) is a member of the LAR family of receptor tyrosine phosphatases and is highly expressed in the nervous system during development. PTPσ is homologous to the Drosophila DLAR, which plays a key role in the targeting of axonal growth cones in flies. We have previously inactivated the Ptprs gene in mice and demonstrated stunted growth, developmental delays, and neurological and neuroendocrine defects in the PTPσ null animals. Here, we mapped the expression of the lac‐Z reporter gene included in the knockout cassette and surveyed the development of the CNS in these mice after birth. The strongest expression of β‐galactosidase (PTPσ) was observed in the hippocampus, cerebral cortex, olfactory bulbs, and subependymal layer. Our analysis reveals hippocampal dysgenesis, reductions in the thickness of the corpus callosum and the cerebral cortex, and late expression of the growth‐associated protein 43 (GAP‐43) in the knockout animals. Architectural abnormalities in the brain and spinal cord were confirmed by immunoreactivity to neurofilament and glial fibrillary acidic protein (GFAP) antibodies. Several of these neural abnormalities were corrected with age, suggesting a delay in neurological development related to the knockout of the Ptprs gene. These data suggest that PTPσ is likely involved in neurogenesis, axonal growth, and axonal pathfinding in the maturation of the mammalian CNS. © 2002 Wiley‐Liss, Inc.
Estrogen inhibition of EAE involves effects on dendritic cell function
Authors: Liu Hong Yan , Buenafe Abigail C. , Matejuk Agata , Ito Atsushi , Zamora Alex , Dwyer Jami , Vandenbark Arthur A. , Offner Halina
Published: October 2002

Estrogen has been found to have suppressive effects on the induction of experimental autoimmune encephalomyelitis (EAE), an animal model for the human disease multiple sclerosis. We have investigated the effects of 17β‐estradiol (E2) treatment on dendritic cells (DCs) in two different mouse models of EAE. The frequency of CD11b+/CD11c+ DCs was significantly decreased in the brain of mice protected from EAE induction by E2 treatment. In addition, the frequency of CD11c+/CD8α+ DCs producing tumor necrosis factor (TNF)α and interferon (IFN)γ in the spleen of E2‐treated mice was dramatically decreased compared to that in control mice with EAE, demonstrating an effect of E2 on DC function. In order to examine E2 effects on DCs in more detail, splenic DCs were cultured in the presence of granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and interleukin (IL)‐4to promote maturation. E2 pretreatment was found to suppress the ability of cultured DCs bearing a mature phenotype to present Ag to myelin basic protein (MBP)‐specific T cells. Analysis of cytokine production demonstrated that E2 decreased TNFα, IFNγ and IL‐12 production in mature DCs. In addition, MBP‐specific T cells cocultured with E2‐pretreated mature DCs in the presence of antigen demonstrated a shift towards production of Th2 cytokines IL‐4 and IL‐10 and a concomitant decrease in the production of Th1 cytokines TNFα and IFNγ. Thus, E2 treatment appears to have multiple effects on the DC population, which may contribute to a down‐regulation or block in the activation of Th1 cells involved in the induction of EAE. © 2002 Wiley‐Liss, Inc.
Urokinase‐type plasminogen activator inhibits amyloid‐β neurotoxicity and fibrillogenesis via plasminogen
Authors: Tucker H. Michael , Kihiko‐Ehmann Muthoni , Estus Steven
Published: October 2002

Amyloid‐β (Aβ) appears central to Alzheimer's disease (AD), aggregates spontaneously, and is neurotoxic to neurons in vitro. Recently, several groups reported a familial AD locus on chromosome 10. Here, we note that urokinase‐type plasminogen activator (uPA) is located within this locus. Previously, we reported that uPA and its functional homolog, tissue‐type plasminogen activator, are induced by Aβ treatment of neurons in vitro as well as in a mouse model of Aβ accumulation in vivo. Moreover, the target of plasminogen activators, plasmin, degraded nonaggregated and aggregated Aβ and modulated Aβ toxicity and deposition. Here, we have evaluated the effects of uPA and plasminogen on Aβ fibril formation and neurotoxicity. We report that the combination of uPA and plasminogen, but neither alone, inhibits Aβ toxicity, reduces Aβ deposition in vitro, and inhibits Aβ fibrillogenesis. We interpret these observations as suggesting that uPA represents a possible candidate gene for the chromosome 10 familial AD locus. © 2002 Wiley‐Liss, Inc.
The resource‐based view of strategy and its value to practising managers
Authors: Connor Tom
Published: October 2002

•A dominant theoretical paradigm in academic strategic management circles is the Resource‐Based View (RBV). This paper reviews the literature of this position and the extent to which the RBV may be seen as a source of practical guidance for managers seeking competitive advantage and strategic success.

•The theories of management academics should be of practical value to managers, otherwise such theories are of limited value. The test of the validity of theorizing about management is whether the theories produced help to improve the art of management. That is the criterion adopted in this paper.

•The RBV is an ‘inside‐out’ perspective, according to which, competitive success lies within the hands of managers themselves and it is from the point of view of practising managers that this paper examines competitiveness. Consequently, the assessment of the RBV will be a purely instrumental one. Does it help managers to manage better?

Copyright © 2002 John Wiley & Sons, Ltd.
Effects of fertilisation on the allyl isothiocyanate profile of above‐ground tissues of New Zealand‐grown wasabi
Authors: Sultana Tamanna , Savage Geoffrey P , McNeil David L , Porter Noel G , Martin Richard J , Deo Bas
Published: October 2002

Wasabi (Wasabia japonica (Miq) Matsum) is a developing crop in New Zealand and is valued for its spicy taste and pungent smell. It is popular as a condiment for traditional and modern Japanese foods. However, the limited area suitable for wasabi production in Japan has resulted in inability to meet increasing market demand. Isothiocyanates (ITCs) are sulphur compounds responsible for the unique flavour of wasabi, with allyl isothiocyanate (AITC) being the main compound responsible for the pungency. In this study, AITC tissue concentration and yield were measured in three above‐ground tissues of the wasabi plant to investigate the effects of different fertiliser, manure and lime treatments. The highest tissue concentration of AITC was found in the rhizomes, ranging from 1564 to 3366 mg kg−1 (fresh weight basis), while the petioles and leaves contained 254–373 and 453–643 mg kg−1 respectively. Fertilisation with ammonium sulphate produced the highest‐quality rhizomes (72% increase in AITC yield) and petioles (64% increase), but the best response in the leaves (51%) resulted from the manure treatment. Nitrogen fertiliser alone reduced the AITC yield by up to 15%. These results should help in formulating guidelines for production of high‐quality wasabi tops containing high levels of AITC.

© 2002 Society of Chemical Industry
Production of dialysable and reduced iron by in vitro digestion of chicken muscle protein fractions
Authors: Diaz Mariana , Vattem Dhiraj , Mahoney Raymond R
Published: October 2002

Muscle foods enhance the absorption of non‐haem iron. We studied the effect of chicken muscle proteins on the production of reduced and dialysable iron following in vitro digestion. At equal protein levels, both soluble and insoluble muscle proteins increased dialysable iron 4–5‐fold. Removal of low‐molecular‐weight components from the soluble fraction caused a 17% drop in dialysable iron. In contrast, egg white had little effect and whey protein was inhibitory. Both soluble and insoluble proteins increased ferrous iron by 8–9‐fold and dialysable ferrous iron by 10–13‐fold. There was an excellent correlation between dialysable iron and sulphhydryl content for all the proteins tested. The results indicate that soluble and insoluble proteins in chicken muscle are equally effective at producing dialysable and reduced iron because of their similar sulphhydryl content.

© 2002 Society of Chemical Industry
Effect of section of yam (Dioscorea cayenensis) tuber used in minisett on the biochemical properties of the resultant tuber
Authors: Wheatley Andrew O , Iyare Osarosemwen A , Asemota Helen N
Published: October 2002

The effect of the section of yam (Dioscorea cayenensis) tuber used as planting material in minisett on the biochemical properties of the resultant tuber was studied. The biochemical parameters invertase (EC 3.2.1.26), acid phosphatase (EC 3.1.3.2), peroxidase (EC1.11.1.7), polyphenol oxidase (EC 1.10.3.1), total sugars and starch were evaluated in tubers resulting from field‐grown and tissue culture‐derived setts of the cultivars Roundleaf and Blackwiss yellow yams. No significant differences were observed between tubers resulting from field‐grown and tissue culture‐derived setts relative to the parameters studied. Invertase activity was found to be highest in tubers from middle‐derived setts, while tail‐derived setts had the lowest activity for both cultivars. Middle‐derived tubers were also found to have significantly higher levels of acid phosphatase activity and starch content. However, middle‐derived tubers had the lowest level of total sugars. Polyphenol oxidase and peroxidase were also found to be significantly higher in tubers from middle‐derived setts. These results suggest a higher rate of active starch formation in tubers from middle‐derived setts.

© 2002 Society of Chemical Industry
Role of matrix metalloproteinase‐9 in in vitro invasion of esophageal carcinoma cells
Authors: Suzuki Tomotaka , Kuwabara Yoshiyuki , Iwata Hiroji , Mitani Masami , Shinoda Noriyuki , Sato Atsushi , Mitsui Akira , Sugiura Masahiko , Kato Joji , Fujii Yoshitaka
Published: October 2002

Background and Objectives

Although some investigators recently suggested that MMP‐9 may play a critical role in invasion and metastasis, along with MMP‐2, in esophageal carcinoma, there has been no direct evidence that MMPs play a critical role in the actual invasion of esophageal carcinoma cells. Here, we investigated the role of MMPs in the in vitro invasion of esophageal carcinoma cell lines (TE‐series).

Methods

Our methods included in vitro invasion assay, gelatin zymography, and enzyme‐linked immunosorbent assay (ELISA).

Results

Four cell lines (but not TE‐5) secreted MMP‐2 and MMP‐9 in the culture medium. Using a quantitative in vitro invasion assay, we found a significant (P = 0.002) correlation between the extent of in vitro invasion and the amount of MMP‐9, but not of MMP‐2, secreted into the conditioned medium in the four cell lines. In these cell lines, R‐94138, a specific MMP‐9 inhibitor, inhibited in vitro invasion in a dose‐dependent manner. Although TE‐5 did not secrete MMP‐2 or MMP‐9, the cells showed a strong in vitro invasion.

Conclusions

Our data suggest that most of the esophageal carcinoma cell lines use MMP‐9 for in vitro invasion, but others may use proteinase(s) other than MMP‐9. J. Surg. Oncol. 2002;81:80–86. © 2002 Wiley‐Liss, Inc.
Is there a minimum number of lymph nodes that should be histologically assessed for a reliable nodal staging of T3N0M0 colorectal carcinomas?
Authors: Cserni Gábor , Vinh‐Hung Vincent , Burzykowski Tomasz
Published: October 2002

Background and Objectives

Because of the existing controversy, we searched for a cutoff value for the number of lymph nodes (LNs) to be examined in order to establish a reliable node‐negative stage in colorectal carcinomas (CRCs).

Methods

From the SEER database, 8,574 T3N0M0 first, single, histologically confirmed, surgically treated CRCs, with at least 1 LN examined histologically, were considered. As a first approach, the relationships between number of examined LNs and 5‐ and 10‐year overall survival (OS) rates, computed by the Kaplan‐Meier method, were assessed. Next, multivariate analysis was performed; a proportional hazards model was fitted to the data and used to obtain a smoothed plot of the martingale residuals vs. the number of negative LNs.

Results

Both OS rates displayed an improvement with an increase of number of LNs examined. The smoothed plot of the martingale residuals against the number of negative LNs was reasonably linear.

Conclusions

Both approaches suggest that there is no cutoff value for the number of LNs to be examined for an adequate nodal staging; for a reliable pN0 staging, as many LNs should be assessed as possible. However, qualitative features of lymph nodes (e.g., those identified by sentinel lymphadenectomy) may alter this recommendation. J. Surg. Oncol. 2002;81:63–69. © 2002 Wiley‐Liss, Inc.
Selective induction of gene expression in rat lung by hexavalent chromium
Authors: Izzotti Alberto , Cartiglia Cristina , Balansky Roumen , D'Agostini Francesco , Longobardi Mariagrazia , De Flora Silvio
Published: October 2002

Multigene‐expression analysis provides a formidable tool for evaluating cellular functions, under either physiological or pathological conditions, and for assessing their modulation by exogenous agents. We investigated multigene expression in the liver and lung of rats receiving intratracheal instillations of sodium dichromate for 3 consecutive days. Nylon membrane cDNA arrays were hybridized with standardized amounts of 32P‐labeled probes, and the results were normalized by making reference to housekeeping genes. The basal expression of 52 of 216 tested genes was 2.1–11.1 times higher in the liver than in the lung of control rats. No alteration of gene expression occurred in the liver of chromium(VI)‐treated rats, consistent with the fact that this metal species, being reduced upstream, can exert effects only locally but not at a distance from the respiratory tract. In contrast, the expression of 56 genes was increased 2.1 to 3.0 times in the lung as an early response to chromium(VI) administration. The altered genes are involved in the metabolic reduction of chromium(VI) and in a variety of interconnected functions, such as multidrug resistance and stress response, protein and DNA repair mechanisms, signal transduction pathways, apoptosis, and cell‐cycle modulation. Thus, short‐term treatment with chromium(VI) by intratracheal administration triggered a variety of defense processes in the lung. Although the use of selected genes does not provide an exhaustive picture of overall gene expression, these findings contribute to our understanding of chromium toxicology and provide a further mechanistic support to the involvement of thresholds in chromium(VI) carcinogenesis. © 2002 Wiley‐Liss, Inc.
Executive and emotional dysfunction in Machado‐Joseph disease
Authors: Zawacki Tricia M. , Grace Janet , Friedman Joseph H. , Sudarsky Lewis
Published: October 2002

Machado‐Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia. Few studies have examined the neuropsychological and neurobehavioral profiles of patients with MJD. In this study, six individuals with MJD were given a battery of neuropsychological tests. Relative impairments on timed verbal attention tasks and verbal fluency (Stroop, Oral Symbol Digit Modalities, and Controlled Oral Word Association Test) were found. Other executive impairments also were seen on the Wisconsin Card Sorting Test, independent of motor dysfunction severity. Moderate‐ to severe levels of depressive symptoms were endorsed by four of the six patients, and caregivers observed increased apathy in the patients. Impaired executive and emotional functioning in MJD does not appear to be related to ataxia severity. These patients did not meet the criteria for dementia. General cognitive abilities, language, list learning, story recall, and untimed tasks of attention were within normal limits. Impaired executive abilities and emotional functioning in MJD patients is consistent with disruption of frontal‐subcortical systems. © 2002 Movement Disorder Society.
Olanzapine treatment for dopaminergic‐induced hallucinations
Authors: Ondo William G. , Levy Joel K. , Vuong Kevin Dat , Hunter Christine , Jankovic Joseph
Published: October 2002

Atypical antipsychotic medications with lower affinities for D2 receptors are considered useful alternatives to treat drug‐induced hallucinations in Parkinson's disease (PD). We conducted a double‐blind, placebo‐controlled, unforced titration, parallel design study (2:1 drug to placebo randomization ratio) using olanzapine (2.5–10 mg/day to effect) in 30 PD patients with drug‐induced hallucinations. We performed an extensive battery of neuropsychological tests, the Unified Parkinson's Disease Rating Scale (UPDRS), assessments of on and off time at baseline and at 9 weeks after starting the medication. Sixteen patients on olanzapine (mean dose, 4.6 mg/night) and 11 on placebo completed the study. Compared with placebo, performance on the UPDRS item 2 (thought disorder), and a structured interview for hallucinations, both tended to improve on drug but neither reached statistical significance. A neuropsychological test battery did not show any significant differences. Total on UPDRS motor scores (P < 0.05) and timed tapping (P < 0.01) worsened while on drug compared to placebo. Bradykinesia (P < 0.01) and gait (P < 0.001) items on the UPDRS largely accounted for this deterioration. After completion of the study, 8 of 16 patients randomly assigned to drug continued olanzapine at a mean dose of 2.4 mg/day. However, at the last recorded visit only 5 of 24 (20.8%) of all patients exposed to drug (including those originally randomly assigned to placebo) remained on olanzapine. In patients with PD, low‐dose olanzapine did not significantly improve hallucinations but did worsen motor function. © 2002 Movement Disorder Society
Rev response elements (RRE) in lentiviruses: An RNAMotif algorithm‐based strategy for RRE prediction
Authors: Lesnik Elena A. , Sampath Ranga , Ecker David J.
Published: October 2002

Lentiviruses (a sub‐family of the retroviridae family) include primate and non‐primate viruses associated with chronic diseases of the immune system and the central nervous system. All lentiviruses encode a regulatory protein Rev that is essential for post‐transcriptional transport of the unspliced and incompletely spliced viral mRNAs from nuclei to cytoplasm. The Rev protein acts via binding to an RNA structural element known as the Rev responsive element (RRE). The RRE location and structure and the mechanism of the Rev‐RRE interaction in primate and non‐primate lentiviruses have been analyzed and compared. Based on structural data available for RRE of HIV‐1, a two step computational strategy for prediction of putative RRE regions in lentivirus genomes has been developed. First, the RNAMotif algorithm was used to search genomic sequence for highly structured regions (HSR). Then the program RNAstructure, version 3.6 was used to calculate the structure and thermodynamic stability of the region of ∼ 350 nucleotides encompassing the HSR. Our strategy correctly predicted the locations of all previously reported lentivirus RREs. We were able also to predict the locations and structures of potential RREs in four additional lentiviruses. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 6, 617–636, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10027
Input impedance of rectangular microstrip antennas on nonradiating edges
Authors: Kundu T. R. , Kar R. , Chatterjee S. , Hazra N. , Chakraborty H. , Kesh A. , Chakraborty J. , Sengupta T. , Roy S. , Bhattacharjee A. K.
Published: October 2002

Closed‐form expressions for the input impedance of half‐wavelength rectangular microstrip antennas fed by a coaxial line at any point on any one of the nonradiating edges and open‐circuited at the ends are derived. Good agreement between computed and measured data is obtained. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 28–31, 2002; DOI 10.1002/mop.10221
J‐modulated 1D directed COSY for precise measurement of proton–proton residual dipolar coupling constants of oligosaccharides
Authors: Pham Tran N. , Liptaj Tibor , Barlow Paul N. , Uhrín Dušan
Published: October 2002

A simple selective 1D experiment for the accurate and precise determination of residual proton–proton dipolar coupling constants of oligosaccharides is proposed. The technique is based on the concept of J‐modulated spectroscopy and provides coupling constants by fitting the peak intensities from a series of spectra to known transfer functions with a precision of ±0.02 Hz for splittings >0.3 Hz. This level of precision is possible owing to limiting the number of sites for polarization transfer. Selective pulses and pulsed field gradients are used for selective excitation and coherence selection, yielding clean, artefact‐free spectra. The technique is illustrated using trisaccharide samples in Pf1 phage. Copyright © 2002 John Wiley & Sons, Ltd.
Cerebral venous and arterial blood volumes can be estimated separately in humans using magnetic resonance imaging
Authors: An Hongyu , Lin Weili
Published: October 2002

Approaches to obtain quantitative, noninvasive estimates of total cerebral blood volume (tCBV) and cerebral venous blood volume (vCBV) separately in humans are proposed. Two sequences were utilized, including a 3D high‐resolution gradient‐echo (GE) sequence and a 2D multi‐echo GE/spin‐echo (MEGESE) sequence. Images acquired by the former sequence provided an estimate of background magnetic field variations (ΔB), while images obtained by the latter sequence were utilized to obtain separate measures of tCBV and vCBV with and without contrast agent. Prior to the calculation of vCBV and tCBV, the acquired images were corrected for signal loss induced by the presence of ΔB. vCBV and tCBV were estimated to be 2.46% ± 0.28% and 3.20% ± 0.41%, respectively, after the ΔB correction, which in turn provided a vCBV/tCBV ratio of 0.77 ± 0.04, in excellent agreement with results reported in the literature. Our results demonstrate that quantitative estimates of vCBV and tCBV can be obtained in vivo. Magn Reson Med 48:583–588, 2002. © 2002 Wiley‐Liss, Inc.
Asymmetrical gradient coil for head imaging
Authors: Tomasi D. , Xavier R.F. , Foerster B. , Panepucci H. , Tannús A. , Vidoto E.L.
Published: October 2002

This work presents a novel approach to develop dedicated transverse gradient coils for head imaging. The proposed coil design is based on the stochastic optimization of an asymmetrical stream function and improves the matching between the region‐of‐interest and the homogeneous gradient volume. Additionally, the electric field produced by these asymmetrical coils is 30% lower than that produced by standard symmetrical designs, which minimizes the risk of magnetostimulation of nerves in fast imaging techniques. A prototype of the asymmetrical gradient coil was built to test the method and magnetic field produced by the prototype was measured. Magnetic field measurements and electrical parameters of coils are in good agreement with theoretical calculations. Magn Reson Med 48:707–714, 2002. © 2002 Wiley‐Liss, Inc.
Increased choline levels coincide with enhanced proliferative activity of human neuroepithelial brain tumors
Authors: Herminghaus Sebastian , Pilatus Ulrich , Möller‐Hartmann Walter , Raab Peter , Lanfermann Heinrich , Schlote Wolfgang , Zanella Friedhelm E.
Published: October 2002

Proton MR spectroscopy (1H MRS)‐visible total choline‐containing compounds (tCho‐compounds) are derivatives of membrane phospholipids and, in part, may act as a long‐term second‐messenger system for cellular proliferation. Experimental evidence suggests increasing concentrations of tCho‐compounds during cellular proliferation. The present study was conducted in order to test the hypothesis that in vivo measurements of tCho‐concentrations using 1H MRS allow assessment of the proliferative activity of neuroepithelial brain tumors presurgically. Single‐voxel 1H MRS (PRESS, TR 1500 ms, TE 135 ms) was performed in 101 patients with neuroepithelial brain tumors prior to surgery and 19 healthy volunteers. Histological diagnoses were confirmed postsurgically according to the WHO classification. Measured tCho‐compound signal intensities were corrected for coil loading, numbers of acquisitions and voxel size, and tCho concentrations calculated as institutional arbitrary units. They were matched with the mean immunohistochemical marker of cell proliferation, the Ki‐67 (MIB.1) labeling index, using correlation analysis according to Spearman. Compared with low‐grade tumors (i.e. WHO grade I/II) and normal white brain matter, high‐grade tumors (i.e. WHO grade III/IV) revealed significantly (p < 0.05) elevated labeling indices paralleled by increasingly elevated tCho‐concentrations. In contrast tCho‐concentrations in low‐grade tumor did not differ significantly from physiological values. A highly significant positive correlation (p < 0.0001, r2 = 0.81) was found between the tCho‐concentration and the labeling index. It was concluded that the determination of tCho‐concentrations using in vivo 1H MRS could provide a novel and noninvasive assessment of the proliferative activity of neuroepithelial brain tumors, pointing at 1H MRS as a useful method for differentiating proliferating from non‐proliferating tissues. Hence, potential indications for the clinical application of 1H MRS are grading tumors presurgically, early detection of anaplastic transformation, and monitoring treatment. Copyright­© 2002 John Wiley & Sons, Ltd.
Node‐disjoint paths and related problems on hierarchical cubic networks
Authors: Fu Jung‐Sheng , Chen Gen‐Huey , Duh Dyi‐Rong
Published: October 2002

Ann‐dimensional hierarchical cubic network [denoted by HCN(n)] contains 2nn‐dimensional hypercubes. The diameter of the HCN(n), which is equal ton+ ⌊(n+ 1)/3⌋ + 1, is about two‐thirds the diameter of a comparable hypercube, even though it uses about half as many links per node. In this paper, a maximal number of node‐disjoint paths are constructed between every two distinct nodes of the HCN(n). Their maximal length is bounded above byn+ ⌊n/3⌋ + 4, which is nearly optimal. The (n+ 1)‐wide diameter andn‐fault diameter of the HCN(n) are shown to ben+ ⌊n/3⌋ + 3 orn+ ⌊n/3⌋ + 4, which are about two‐thirds those of a comparable hypercube. Our results reveal that the HCN(n) has a smaller wide diameter and fault diameter than those of a comparable hypercube. © 2002 Wiley Periodicals, Inc.
Overexpression of Parkinson's disease‐associated α‐SynucleinA53T by recombinant adeno‐associated virus in mice does not increase the vulnerability of dopaminergic neurons to MPTP
Authors: Dong Zhizhong , Ferger Boris , Feldon Joram , Büeler Hansruedi
Published: October 2002

Mutations in the α‐synuclein gene are linked to a rare dominant form of familial Parkinson's disease, and α‐synuclein is aggregated in Lewy bodies of both sporadic and dominant Parkinson's disease. It has been proposed that mutated α‐synuclein causes dopaminergic neuron loss by enhancing the vulnerability of these neurons to a variety of insults, including oxidative stress, apoptotic stimuli, and selective dopaminergic neurotoxins, such as 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP). To test this hypothesis in vivo, we overexpressed human α‐synucleinA53T in the substantia nigra of normal and MPTP‐treated mice by rAAV‐mediated gene transfer. Determination of dopaminergic neuron survival, striatal tyrosine hydroxylase fiber density, and striatal content of dopamine and its metabolites in rAAV‐injected and uninjected hemispheres demonstrated that α‐synucleinA53T does not increase the susceptibility of dopaminergic neurons to MPTP. Our findings argue against a direct detrimental role for (mutant) α‐synuclein in oxidative stress and/or apoptotic pathways triggered by MPTP, but do not rule out the possibility that α‐synuclein aggregation in neurons exposed to oxidative stress for long periods of time may be neurotoxic. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 1–10, 2002
Application of the three‐way decomposition for matrix compression
Authors: Ibraghimov Ilghiz
Published: October 2002

We present a new method to compress and invert 3D integral operators on rectangular non‐regular grids. This method requires a small amount of memory to store the compressed matrix and in most cases can provide a good preconditioner for the solution of linear systems with this matrix. We demonstrate efficiency of this method for the solution of some model discrete problems associated with
∫A(x̄,ȳ)f(x̄)dx̄=u(ȳ), x̄,ȳϵℝ3
, where A(x̄,ȳ) such as 1/∣x̄−ȳ∣ is considered on a non‐regular grid. The arithmetical complexity of matrix–vector and preconditioner–vector multiplications are about N4/3 operations and there are only about N2/3 words of memory to store. Copyright © 2002 John Wiley & Sons, Ltd.
Directional bilateral asymmetry in human sacral morphology
Authors: Plochocki Jeffrey H.
Published: October 2002

Directional bilateral asymmetries in human gross skeletal morphology are largely attributable to differential mechanical loading from handedness during endochondral bone growth. While much has been done in the way of identifying directional asymmetries of the upper limb in relation to handedness, comparatively little research has focused on asymmetry in the lower body. The present paper analyses asymmetry in the human sacrum in a sample of 238 modern individuals. Measurements of right and left sides of the lateral and posterior breadths of the alae and the maximum height of the auricular surface were used. Asymmetry was calculated as: [(left side − right side) ÷ right side] * 100. Directional asymmetry was identified using a one‐sample t‐test against a hypothesized mean of zero. Significant directional asymmetry (P < 0.05) was found in all three dimensions. The pattern of asymmetry is consistent with models describing the influence of right‐handedness on the lower body, which predicts that left side dimensions will be larger. Copyright © 2002 John Wiley & Sons, Ltd.
The effect of child support on welfare exits and re‐entries
Authors: Huang Chien‐Chung , Kunz James , Garfinkel Irwin
Published: October 2002

Much of the literature on welfare dynamics has focused on the effects of recipient characteristics and state‐level characteristics such as welfare benefits and economic conditions; there has been very little analysis on the effects of child support. This paper, using the 1979‐1996 National Longitudinal Survey of Youth, examines whether child support affects the likelihood of leaving and re‐entering welfare. The results indicate that strong child support enforcement is important in helping young mothers exit and stay off welfare. Women with $1000 child support payments in the previous year were 18 percent more likely to exit welfare and 12 percent less likely to re‐enter welfare. Compared with women in states that pursued child support least vigorously, women in states that had passed extensive child support enforcement legislation and that spent more money on child support enforcement were 79 percent more likely to exit welfare and about 60 percent less likely to re‐enter welfare. © 2002 by the Association for Public Policy Analysis and Management.
Does it pay to move from welfare to work?
Authors: Danziger Sheldon , Heflin Colleen M. , Corcoran Mary E. , Oltmans Elizabeth , Wang Hui‐Chen
Published: October 2002

The 1996 Personal Responsibility and Work Opportunity Reconciliation Act requires welfare recipients to look
for work and has made it more difficult for nonworking recipients to remain on the welfare rolls. In addition,
the economic boom of the 1990s and changes in federal and state policies have raised the net income gain
associated with moving from welfare to work. This paper analyzes data from a panel survey of single mothers, all
of whom received welfare in February 1997. In 1999, those who left welfare and were working had a higher
household income and lower poverty rate, experienced a similar level of material hardship, engaged in fewer
activities to make ends meet, and had lower expectations of experiencing hardship in the near future than did
nonworking welfare recipients. Estimations of fixed‐effect regressions of income that control for both
observable and unobservable time‐invariant characteristics show that monthly net income increases by
$2.63 for every additional hour of work effort. About 60 percent of the observed monthly income
difference between wage‐reliant and welfare‐reliant mothers can be attributed to differences in
their work effort. Thus, after welfare reform, it does pay to move from welfare to work. © 2002 by the
Association for Public Policy Analysis and Management.