bluuebunny/crossref_metadata_2025 huggingface dataset:
Intracellular compartmentation of pyruvate in primary cultures of cortical neurons as detected by 13C NMR spectroscopy with multiple 13C labels
Authors: Cruz Fátima , Villalba Martín , García‐Espinosa María A. , Ballesteros Paloma , Bogónez Elena , Satrústegui Jorgina , Cerdán Sebastián
Published: August 2002

The intracellular compartmentation of pyruvate in primary cultures of cortical neurons was investigated by high resolution 13C NMR using mixtures of different pyruvate precursors conveniently labeled with 13C or unlabeled. Cells were incubated with 1–5 mM (1‐13C, 1,2‐13C2 or U‐13C6) glucose only or with mixtures containing 1.5 mM (1‐13C or U‐13C6) glucose, 0.25–2.5 mM (2‐13C or 3‐13C) pyruvate and 1 mM malate. Extracts from cells and incubation media were analyzed by 13C NMR to determine the relative contributions of the different precursors to the intracellular pyruvate pool. When (13C) glucose was used as the sole substrate fractional 13C enrichments and 13C isotopomer populations in lactate and glutamate carbons were compatible with a unique intracellular pool of pyruvate. When mixtures of (13C) glucose, (13C) pyruvate and malate were used, however, the fractional 13C enrichments of the C2 and C3 carbons of lactate were higher than those of the C2 and C3 carbons of alanine and depicted a different 13C isotopomer distribution. Moreover, neurons incubated with 1 mM (1,2‐13C2) glucose and 0.25–5 mM (3‐13C) pyruvate produced exclusively (3‐13C) lactate, revealing that extracellular pyruvate is the unique precursor of lactate under these conditions. These results reveal the presence of two different pools of intracellular pyruvate; one derived from extracellular pyruvate, used mainly for lactate and alanine production and one derived from glucose used primarily for oxidation. A red‐ox switch using the cytosolic NAD+/NADH ratio is proposed to modulate glycolytic flux, controlling which one of the two pyruvate pools is metabolized in the tricarboxylic acid cycle when substrates more oxidized or reduced than glucose are used. © 2001 Wiley‐Liss, Inc.
Metabolic changes in quinolinic acid‐lesioned rat striatum detected non‐invasively by in vivo 1H NMR spectroscopy
Authors: Tkáč Ivan , Keene C. Dirk , Pfeuffer Josef , Low Walter C. , Gruetter Rolf
Published: August 2002

Intrastriatal injection of quinolinic acid (QA) provides an animal model of Huntington disease. In vivo 1H NMR spectroscopy was used to measure the neurochemical profile non‐invasively in seven animals 5 days after unilateral injection of 150 nmol of QA. Concentration changes of 16 metabolites were measured from 22 μl volume at 9.4 T. The increase of glutamine ((+25 ± 14)%, mean ± SD, n = 7) and decrease of glutamate (−12 ± 5)%, N‐acetylaspartate (−17 ± 6)%, taurine (−14 ± 6)% and total creatine (−9 ± 3%) were discernible in each individual animal (P < 0.005, paired t‐test). Metabolite concentrations in control striata were in excellent agreement with biochemical literature. The change in glutamate plus glutamine was not significant, implying a shift in the glutamate‐glutamine interconversion, consistent with a metabolic defect at the level of neuronal‐glial metabolic trafficking. The most significant indicator of the lesion, however, were the changes in glutathione ((−19 ± 9)%, P < 0.002)), consistent with oxidative stress. From a comparison with biochemical literature we conclude that high‐resolution in vivo 1H NMR spectroscopy accurately reflects the neurochemical changes induced by a relatively modest dose of QA, which permits one to longitudinally follow mitochondrial function, oxidative stress and glial‐neuronal metabolic trafficking as well as the effects of treatment in this model of Huntington disease. © 2001 Wiley‐Liss, Inc.
NF‐κB and IκBα expression following traumatic brain injury to the immature rat brain
Authors: Sanz Olga , Acarin Laia , González Berta , Castellano Bernardo
Published: August 2002

NF‐κB is one of the most important modulators of stress and inflammatory gene expression in the nervous system. In the adult brain, NF‐κB upregulation has been demonstrated in neurons and glial cells in response to experimental injury and neuropathological disorders, where it has been related to both neurodegenerative and neuroprotective activities. Accordingly, the aim of this study was to evaluate the cellular and temporal patterns of NF‐κB activation and the expression of its endogenous inhibitor IκBα following traumatic brain injury (TBI) during the early postnatal weeks, when the brain presents elevated levels of plasticity and neuroprotection. Our results showed that cortical trauma to the 9‐day‐old rat brain induced a very fast upregulation of NF‐κB, which was maximal within the first 24 hours after injury. NF‐κB was mainly observed in neuronal cells of the degenerating cortex as well as in astrocytes located in the corpus callosum adjacent to the injury, where a pulse‐like pattern of microglial NF‐κB activation was also found. In addition, astrocytes of the corpus callosum, and microglial cells to a lower extent, also showed de novo expression of IκBα within the time of NF‐κB activation. This study suggests an important role of NF‐κB activation in the early mechanisms of neuronal death or survival, as well as in the development of the glial and inflammatory responses following traumatic injury to the immature rat brain. © 2002 Wiley‐Liss, Inc.
Regeneration of primary sensory axons into the adult rat spinal cord via a peripheral nerve graft bridging the lumbar dorsal roots to the dorsal column
Authors: Dam‐Hieu Phong , Liu Song , Choudhri Tanvir , Said Gérard , Tadié Marc
Published: August 2002

This study investigated the feasibility of using a peripheral nerve autograft (NAG) to promote and guide regeneration of sensory axons from the caudal lumbar dorsal roots to the rostral dorsal column following a lower thoracic cordotomy in adult rats. After a left hemicordotomy at the T13 vertebra level and ipsilateral L3 and L4 rhizotomies, a peripheral NAG (peroneal nerve) was connected to the distal roots stumps, then implanted into the left dorsal column 10 mm rostral to hemicordotomy site (n = 12). After surgery, all animals of the experimental group experienced complete anesthesia in their left hindlimb. Three months later, a slight response to nociceptive stimulation reappeared in L3 and/or L4 dermatomes in 6 of the 12 experimental animals. None of these animals exhibited self‐mutilation. Nine months after surgery, we performed retrograde tracing studies by injecting horseradish peroxidase (HRP) into the left dorsal column 30 mm rostral to the NAG implantation site. In eight animals, we found HRP‐stained neurons in the left L3 and/or L4 dorsal root ganglia (DRG). The mean number of HRP‐stained neurons per DRG was 71 ± 92 (range 2–259). In control groups, no HRP‐stained neurons were found in L3 or L4 DRG. Histological analysis of the NAG showed evidence of axonal regeneration in all 8 animals with positive retrograde labeling of DRG neurons. However, we did not find a statistical correlation between the number of HRP‐stained neurons and the degree of sensory recovery. This study demonstrates that an NAG joining dorsal roots to the dorsal column, thus shunting the original CNS‐PNS junction, can support regeneration of central axons from DRG primary sensory neurons into the dorsal column over distances of at least 30 mm despite the inhibitory influence of the CNS white matter. © 2002 Wiley‐Liss, Inc.
Differential distribution of laminins in Alzheimer disease and normal human brain tissue
Authors: Palu Edouard , Liesi Päivi
Published: August 2002

Immunocytochemistry, Western blotting, and RT‐PCR were used to identify the isoforms of laminin expressed in the Alzheimer disease, but not in normal human brain tissue. We found that α1 laminin was heavily over‐expressed in Alzheimer disease frontal cortex, and localized in reactive astrocytes of the grey and white matter, and as punctate deposits in the senile placques of the Alzheimer brain tissue. Antibodies against the C‐terminal neurite outgrowth domain of the γ1 laminin demonstrated expression of the γ1 laminin in GFAP‐immunoreactive reactive astrocytes of the Alzheimer disease frontal cortex. The γ1 laminin was also heavily over‐expressed in reactive astrocytes of both grey and white matter. Although antibodies against the C‐terminal neurite outgrowth domain failed to localize γ1 laminin in senile plaques, antibodies against the N‐terminal domains of the γ1 laminin demonstrated γ1 laminin as punctate deposits in the senile plaques. The present results indicate that enhanced and specialized expression patterns of α1 and γ1 laminins distinctly associate these two laminins with the Alzheimer disease. The fact that domain specific antibodies localize both α1 and γ1 laminins in the senile plaques as punctate deposits and in astrocytes of both the gray and white matter indicate that these laminins and their specific domains may have distinct functions in the pathophysiology of the Alzheimer disease. © 2002 Wiley‐Liss, Inc.
Alpha‐motoneurons of the injured cervical spinal cord of the adult rat can reinnervate the biceps brachii muscle by regenerating axons through peripheral nerve bridges: Combined ultrastructural and retrograde axonal tracing study
Authors: Rhrich‐Haddout F. , Kassar‐Duchossoy L. , Bauchet L. , Destombes J. , Thiesson D. , Butler‐Browne G. , Lyoussi B. , Baillet‐Derbin C. , Horvat J.C.
Published: August 2002

Following our previous studies related to brachial plexus injury and repair, the present experimentation was designed to examine the ultrastructural features of those motoneurons of the locally injured cervical spinal cord of adult rats that were seen to regenerate into peripheral nerve (PN) bridges and to reinnervate nearby skeletal muscles. Here, the peripheral connection of the PN bridge was made with the biceps brachii (BB) muscle. Three months postsurgery, the spinal motoneurons labelled by retrograde axonal transport of horseradish peroxidase (HRP), after its injection into the BB, were selected on thick sections, using light microscopy, for the presence of dark amorphous granules of the HRP reaction product. Serial ultrathin sections were then made from the selected material. For the 10 labelled neurons studied, we examined the synaptic boutons present on the membrane of the neuronal soma. For five of them, we could observe three of the six types of synaptic boutons described for the alpha‐motoneurons of the cat (S‐type with spherical vesicles, F‐types with flattened vesicles, and C‐type with subsynaptic cistern). The largest boutons (type C) are specific to alpha‐motoneurons. In comparison to normal material, we noticed a decrease in the number of boutons and an increase in the number of glial processes. After a transient phase of trophic changes, the reinnervated BB muscles showed a return of their fibers to nearly normal diameters as well as evidence of fiber type grouping. Simultaneous staining with silver and cholinesterase also revealed the presence of new motor endplates frequently contacted by several motoneurons. The present study indicates that, after a local spinal injury, typical alpha‐motoneurons can reinnervate a skeletal muscle by regenerating axons into the permissive microenvironment provided by a PN graft. These data offer prospects for clinical reconstruction of the brachial plexus after avulsion of one or several nerve roots. J. Neurosci. Res. 64:476–486, 2001. © 2001 Wiley‐Liss, Inc.
Dopamine receptor antagonists prevent the d‐amphetamine‐induced increase in calcitonin gene‐related peptide levels in ventral striatum
Authors: Gruber Susanne H.M. , Nomikos George G. , Mathé Aleksander A.
Published: August 2002

Microdialysis in conjunction with radioimmunoassay (RIA) were used to study the effects of acute d‐amphetamine or dopamine (DA) receptor antagonists administration on extracellular concentrations of calcitonin gene‐related peptide (CGRP) in the ventral striatum of the rat. One hour after the subcutaneous (s.c.) injection of saline, the DA‐D1 receptor antagonist SCH 23390 (0.3 mg/kg) or the DA‐D2/3 receptor antagonist raclopride (1.0 mg/kg), one additional s.c. injection of saline or d‐amphetamine (1.5 mg/kg) was given. The dialysates were collected at 60‐min intervals; CGRP‐like immunoreactivities (−LI) were determined by RIA. d‐Amphetamine significantly increased extracellular CGRP‐LI concentrations compared to the control animals. Administration of either SCH 23390 or raclopride did not significantly affect CGRP‐LI concentrations. Pretreatment with either SCH 23390 or raclopride abolished the stimulatory effect of d‐amphetamine on CGRP‐LI levels. The results show that d‐amphetamine administration results in an increase in extracellular concentrations of CGRP in the ventral striatum through a mechanism that appears to involve stimulation of either DA‐D1 or DA‐D2/3 receptors. The results also indicate that changes in dopaminergic neurotransmission affect CGRP outflow in the ventral striatum in a phasic but not tonic manner. J. Neurosci. Res. 64:606–611, 2001. © 2001 Wiley‐Liss, Inc.
Glial cell death induced by overexpression of α‐synuclein
Authors: Stefanova Nadia , Klimaschewski Lars , Poewe Werner , Wenning Gregor K. , Reindl Markus
Published: August 2002

α‐Synuclein is present in intracellular protein aggregates that are hallmarks of common neurodegenerative disorders including Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. α‐Synuclein is localized in neurons and presynaptic terminals. Under pathological conditions, however, it is also found in glia. The role of α‐synuclein in glial cells and its relevance to the molecular pathology of neurodegenerative diseases is presently unclear. To investigate the consequence of α‐synuclein overexpression in glia, we transfected U373 astrocytoma cells with vectors encoding wild‐type human α‐synuclein or C‐terminally truncated synuclein fused to red fluorescent protein. α‐synuclein immunocytochemistry of transfected astroglial cells revealed diffuse cytoplasmic labeling associated with discrete inclusions both within cell bodies and processes. Susceptibility to oxidative stress was increased in astroglial cells overexpressing α‐synuclein, particularly in the presence of cytoplasmic inclusions. Furthermore, overexpression of α‐synuclein induced apoptotic death of astroglial cells as shown by TUNEL staining. Our in vitro model is the first to replicate salient features of the glial pathology associated with α‐synucleinopathies. It provides a simple testbed to further explore the cascade of events that leads to apoptotic glial cell death in some of these disorders; it may also be useful to assess the effects of therapeutic interventions including antioxidative and antiapoptotic strategies. J. Neurosci. Res. 65:432–438, 2001. © 2001 Wiley‐Liss, Inc.
Altered circadian cortisol secretion in Alzheimer's disease: Clinical and neuroradiological aspects
Authors: Giubilei F. , Patacchioli F.R. , Antonini G. , Monti M. Sepe , Tisei P. , Bastianello S. , Monnazzi P. , Angelucci L.
Published: August 2002

We determined circadian salivary cortisol levels in 18 outpatients affected by probable Alzheimer's disease (AD) and looked for a possible correlation with both cognitive impairment and brain CT scan findings. The diagnosis of probable AD was made according to the NINCDS‐ADRDA criteria. The severity of cognitive impairment was quantified using the Mini Mental State Examination (MMSE) and the Global Deterioration Scale (GDS). Cortisol levels were measured on saliva samples collected at 08:00 AM and 08:00 PM. For each sample, a duplicate cortisol measurement was performed on 50 μl of saliva by means of a modified commercial radioimmunoassay kit. At the same time, 11 of the 18 AD patients enrolled also underwent a brain CT scan to estimate cerebral atrophy by using linear indexes. The mean value of cortisol levels was significantly higher in AD patients than in controls at both the morning and the evening measurements, and the circadian fluctuation of cortisol was less marked in AD patients than in controls, although this difference did not reach statistical significance. Morning cortisol levels were significantly correlated to both the MMSE and the GDS scores. A significant correlation was also found between morning cortisol levels and all the cerebral atrophy indexes. By contrast, no correlation was observed between evening cortisol levels or cortisol circadian fluctuations and either cognitive impairment or cerebral atrophy. In conclusion, despite the potential biases deriving from the small sample and the limitations of the CT scan study, our results suggest that, in AD patients, hypercortisolemia is correlated with severity of the disease. J. Neurosci. Res. 66:262–265, 2001. © 2001 Wiley‐Liss, Inc.
Confronting failure: antecedents and consequences of shared beliefs about failure in organizational work groups
Authors: Cannon Mark D. , Edmondson Amy C.
Published: August 2002

This paper contributes to a growing body of research on shared cognition by examining shared beliefs about failure in organizational work groups. We argue that the popular ideal of organizational learning from failure is likely to be impeded by powerful psychological and organizational barriers to engaging in behaviors through which this can occur. We hypothesize that people hold tacit beliefs about appropriate responses to mistakes, problems and conflict, and that these are shared within and vary between organizational work groups (H1). These shared beliefs vary in the extent to which they take a learning approach to failure – specifically in the extent to which they endorse identifying, discussing, and analysing mistakes, problems, and conflicts. We also hypothesize that effective coaching, clear direction and a supportive work context influence beliefs related to failure (H2), and that beliefs about failure influence group performance (H3). These hypotheses combine to suggest a theoretical model of antecedents and consequences of shared beliefs about failure in work groups. The paper presents empirical evidence from a recent field study to test the model and finds support for Hypotheses 1, 2, and 3. Hypothesis 4 – that shared beliefs about failure mediate between the antecedents and the outcome of group performance – was not supported. Copyright © 2001 John Wiley & Sons, Ltd.
An objective classification of rainfall events on the basis of their convective features: application to rainfall intensity in the northeast of spain
Authors: Llasat María‐Carmen
Published: August 2002

A system of rainfall events classification on the basis of their hydrometeorological characteristics is proposed. The objective is the characterization of the different event classes and their application in modelling intensity–duration–frequency curves and design hyetographs. A parameter related to the greater or lesser convective character of the precipitation, designated as β*, is defined, while its distribution throughout the entire series of the sample is studied. In addition, the main features of the different classes obtained and their relationship to floods and rainfall damage events have been analysed. The intensity series of the Jardí pluviograph (Barcelona, Spain) between 1927 and 1981 is used as a sample series. Copyright © 2001 Royal Meteorological Society
Interannual variability of lower‐tropospheric moisture transport during the Australian monsoon
Authors: Godfred‐Spenning Christopher R. , Reason Christopher J. C.
Published: August 2002

The interannual variability of the horizontal lower‐tropospheric moisture transport associated with the Australian summer monsoon has been analysed for the 1958–99 period. The 41‐season climatology of moisture flux integrated between the surface and 450 hPa showed moderate levels of westerly transport in the month before Australian monsoon onset, associated with cross‐equatorial flow in the Sulawesi Sea and west of Borneo. In the month after onset the westerly moisture transport strengthened dramatically in a zonal belt stretching from the Timor Sea to the Western Equatorial Pacific, constrained between the latitudes 5 and 15 °S, and associated with a poleward shift in the Intertropical Convergence Zone and deepening of the monsoon trough. Vertical cross‐sections showed this transport extending from the surface to the 500 hPa level. In the second and third months after onset the horizontal flow pattern remained similar, although flux magnitudes progressively decreased, and the influence of trade winds became more pronounced over northern Australia.

Nine El Niño and six La Niña seasons were identified from the data set, and composite plots of the affected years revealed distinct, and in some cases surprising, alterations to the large‐scale moisture transport in the tropical Australian–Indonesian region. During an El Niño it was shown that the month prior to onset, in which the moisture flux was weaker than average, yielded to a dramatically stronger than average flux during the following month, with a zone of westerly flux anomalies stretching across the north Australian coast and Arafura Sea. The period of enhanced moisture flux during an El Niño is relatively short‐lived, with drier easterly anomalies asserting themselves during the following 2 months, suggesting a shorter than usual monsoon period in north Australia. In the La Niña composite, the initial month after onset shows a tendency to weaker horizontal moisture transport over the Northern Territory and Western Australia. The subsequent 2 months show positive anomalies in flux magnitude over these areas; the overall effect is to prolong the monsoon.

Comparison of these results with past research has led us to suggest that the tendency for stronger (weaker) circulations to arise in the initial month of El Niño (La Niña) events is a result of mesoscale changes in soil moisture anomalies on land and offshore sea surface temperature (SST) anomalies, brought about by the large‐scale alterations to SST and circulation patterns during the El Niño–Southern Oscillation. The soil moisture and SST anomalies initially act to enhance (suppress) the conditions necessary for deep convection in the El Niño (La Niña) cases via changes in land–sea thermal contrast and cloud cover. Copyright © 2002 Royal Meteorological Society.
Experimental values of the UV index during 2000 at two locations in Mediterranean Spain
Authors: Martínez‐Lozano J. A. , Tena F. , Marín M. J. , Utrillas M. P. , Lorente J. , De Cabo X. , González‐Frías C.
Published: August 2002

During the past 2 years automatic measurements of UVB solar irradiance have been made sstematically at ground level at a number of points in Spain. Values for both the ultraviolet erythemal radiation and the ultraviolet index (UVI) have been obtained from these measurements. In this paper we present a first analysis of these values for two locations on the Spanish Mediterranean coast—Valencia and Barcelona—an area where a large part of the summer tourism of the country is concentrated. During the summer the UVI only reached ten on three occasions, though a value of nine was reached repeatedly (both classified as extreme risk by the World Health Organization). It has been shown that, in 90% of cases, the maximum daily value of UVI deviates from the value at solar 12 : 00 by, at most, one unit. The annual accumulated doses are expressed as a function of the minimum erythemal doses corresponding to each of the four usual skin phototypes. Copyright © 2002 Royal Meteorological Society
2,3,7,8,12,13,17,18-Octachloroporphyrin
Authors: SENGE MATHIAS O. , FLÖGEL OLIVER , RUHLANDT-SENGE KARIN
Published: August 2002

Synthesis of 3,4-dichloropyrrole and reaction with formaldehyde and p-toluene sulfonic acid catalysis, followed by oxidation with Ag 2 O allows a low yield entry into 2,3,7,8,12,13,17,18-octachloroporphyrin. The extremely low solubility of the free base requires work-up in the presence of metallo acetates for in situ formation of metal complexes. Utilizing this method, zinc(II) and nickel(II) complexes of the title compound were prepared as the first examples of a novel porphyrin class bearing only β-halogeno substituents. In addition, the first crystal structure of a 3,4-dihalopyrrole, 3,4-dichloropyrrole, is reported.
Kinetics of zinc ion incorporation in base into a centrally aprotic beta-octabrominated cationic water-soluble porphyrin and its monolithium complex
Authors: BAILEY SABRINA L. , HAMBRIGHT P.
Published: August 2002

The kinetics of zinc incorporation from pH 12 to 13 into the centrally aprotic BrP (4)2+ form of beta-octabromo-meso-tetrakis(N-methyl-4-pyridyl)porphyrin and its monolithium complex were studied at 25.0 °C, ionic strength (I) = 0.10. The reactions were first order in porphyrin and total zinc concentrations. For BrP (4)2+, the specific rate constant was 5.1 × 105 M -1 s -1 for Zn ( OH )2 aq , 9.9 × 104 M -1 s -1 for [Formula: see text] and [Formula: see text] was unreactive. The Li - BrP (4)3+ complex had a formation constant with BrP (4)2+ of 1.1 × 103 M -1 from both kinetic and equilibrium measurements. In solutions containing both BrP (4)2+ and Li - BrP (4)3+, zinc incorporation proceeded only through BrP (4)2+.
Seismostratigraphy and sediment studies of Lake Hestvatn, southern Iceland: implications for the deglacial history of the region
Authors: Hardardóttir Jórunn , Geirsdóttir Áslaug , Sveinbjörnsdóttir Árny E.
Published: August 2002

Core 95‐HV was obtained from Lake Hestvatn, southern Iceland, after a seismic survey had identified a sediment sequence over 45 m thick in the lake. The core penetrated ca. 25 m into the sediment correlating with seismostratigraphic unit 2 of alternating seismic facies, with semi‐parallel reflectors of high amplitude and chaotic reflectors. Detailed sedimentological, chemical, magnetic and chronostratigraphical analyses on core 95‐HV, combined with interpretation of the seismic survey, show considerable changes in the sedimentary environment between ca. 10300 and 9000 14C yr BP (reservoir corrected). The lowermost ca. 12 m of the core was deposited in a marine environment during energy shifts from a very rapid accumulation of sandy turbidite units to slower deposition of suspended fine‐grained sediments. The turbidite units, thought to have originated from catastrophic outburst floods (jökulhlaup), contributed greatly to the high sediment accumulation rate at the Younger Dryas–Preboreal transition. Further change in the sedimentary environments is evidenced by the deposition of organic‐rich lake sediment with abundant tephra layers, starting at ca. 9000 yr BP (seismostratigraphic unit 3). The study shows that the inland glacier did not override the site of Hestvatn during the time of sediment deposition in the lake basin. Copyright © 2001 John Wiley & Sons, Ltd.
Pollen‐based biome reconstructions for Colombia at 3000, 6000, 9000, 12 000, 15 000 and 18 000 14C yr ago: Late Quaternary tropical vegetation dynamics
Authors: Marchant Robert , Behling Hermann , Berrio Juan‐Carlos , Cleef Antoine , Duivenvoorden Joost , Hooghiemstra Henry , Kuhry Peter , Melief Bert , Schreve‐Brinkman Elisabeth , Van Geel Bas , Van der Hammen Thomas , Van Reenen Guido , Wille Michael
Published: August 2002

Colombian biomes are reconstructed at 45 sites from the modern period extending to the Last Glacial Maximum (LGM). The basis for our reconstruction is pollen data assigned to plant functional types and biomes at six 3000‐yr intervals. A reconstruction of modern biomes is used to check the treatment of the modern pollen data set against a map of potential vegetation. This allows the biomes reconstructed at past periods to be assessed relative to the modern situation. This process also provides a check on the a priori assignment of pollen taxa to plant functional types and biomes. For the majority of the sites, the pollen data accurately reflect the potential vegetation, even though much of the original vegetation has been transformed by agricultural practices. At 18 000 14C yr BP, a generally cool and dry environment is reflected in biome, assignments of cold mixed forests, cool evergreen forests and cool grassland–shrub; the latter extending to lower altitudes than presently recorded. This signal is strongly recorded at 15 000 and 12 000 14C yr BP, the vegetation at these times also reflecting a relatively cool and dry environment. At 9000 14C yr BP there is a shift to biomes thought to result from slightly cooler environmental conditions. This trend is reversed by 6000 14C yr BP; most sites, within a range of different environmental settings, recording a shift to more xeric biome types. There is an expansion of steppe and cool mixed‐forest biomes, replacing tropical dry forest and cool grassland–shrub biomes, respectively. These changes in biome assignments from the modern situation can be interpreted as a biotic response to mid‐Holocene climatic aridity. At 3000 14C yr BP the shift is mainly to biomes characteristic of slightly more mesic environmental conditions.

There are a number of sites that do not change biome assignment relative to the modern reconstruction, although the affinities that these sites have to a specific biome do change. These ‘anomalies’ are interpreted on a site‐by‐site basis. Spatially constant, but differential response of the vegetation to climatic shifts are related to changes in moisture sources and the importance of edaphic controls on the vegetation. The Late Quaternary reconstruction of large‐scale vegetation dynamics in Colombia allows an understanding of the environmental controls on these to be developed. In particular, shifts in the character of the main climatic systems that influence Colombian vegetation are described. Copyright © 2002 John Wiley & Sons, Ltd.
Raman study of triblock polyether/LiCF3SO3 polymeric electrolytes
Authors: Silva R. A. , Goulart Silva G. , Pimenta M. A.
Published: August 2002

A micro‐Raman study of triblock polyether/LiCF3SO3 polymeric electrolytes was carried out over a wide range of salt concentrations at room temperature. The different associated species were evidenced by means of a lineshape analysis of the bands related to the symmetric stretching mode ν1 of the SO3− termination and to the C–S vibration of the CF3SO3− anion. The Raman results reveal that the appearance of new associated species coincides with the saturation of prior species. Copyright © 2001 John Wiley & Sons, Ltd.
Raman study of solid ammonia at high pressures and low temperatures
Authors: Kume T. , Sasaki S. , Shimizu H.
Published: August 2002

Raman measurements on solid ammonia were carried out at pressures up to 15 GPa and at temperatures down to 20 K by using a diamond anvil cell in order to determine the pressure–temperature phase diagram. From the changes in the Raman spectrum at the phase transition, the stability regions of phases I, II, III and IV were investigated. The triple point of phases I, II, and IV is suggested to exist around 1.1 GPa and 220 K. The Raman spectra observed in the solid phase IV at low temperatures demonstrated several new peaks, and provide the support for the recent proposal for its crystal structure. Copyright © 2001 John Wiley & Sons, Ltd.
Drug‐induced corneal hydration changes monitored in vivo by non‐invasive confocal Raman spectroscopy
Authors: Erckens Roel J. , Jongsma Franciscus H. M. , Wicksted James P. , Hendrikse Fred , March Wayne F. , Motamedi Massoud
Published: August 2002

It is well established that the state of corneal hydration plays a crucial role in maintaining optimal vision. Therefore, any knowledge that can be obtained non‐invasively about the status of corneal hydration could be of significant clinical value. A novel confocal Raman spectroscopic technique was used to monitor non‐invasively drug‐induced hydration changes in the rabbit cornea. The spectroscopic technique enables one to monitor the changes in water content of the cornea while the confocal probing reduces interference of signals from adjacent tissues and allows for measurement of corneal hydration at various depths. The corneal hydration is altered by applying a dehydrating agent (Muro 128®) topically on the cornea. To determine the corneal hydration status, the OH/CH ratio between the Raman intensity of the water OH mode at 3390 cm−1 and the protein CH stretching mode at 2945 cm−1 is calculated. In the middle of the corneal stroma after 10 min, Muro 128®‐treated corneas show an average decrease of about 30% in the OH/CH ratio (1.27 ± 0.13) compared with the untreated corneas (1.76 ± 0.09). In this in vivo model it is possible to monitor the hydration status of the living cornea using the Raman spectroscopic technique. Copyright © 2001 John Wiley & Sons, Ltd.
Blue shift of Raman peak from coated TiO2 nanoparticles
Authors: Xu C. Y. , Zhang P. X. , Yan L.
Published: August 2002

Nanosized TiO2 particles coated with dodecylbenzenesulfonic acid (DBS) and stearic acid (St) were prepared using the hydrothermal procedure. The average size of the DBS/TiO2 and St/TiO2 particles is very small, about 8 nm. Raman spectra from DBS/TiO2 and St/TiO2 were measured, and scattering signals from both TiO2 and the coating were observed. It was found that in contrast to the red shift of Raman peaks in the nanoparticles with decrease in particle size, a blue shift, namely the Raman peak shift to the higher wavenumber side, in the coated particles was recorded. It was also found that different coatings show different extents of Raman shifts. The possible origin of the blue shift is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Temperature‐dependent Raman scattering study of Fe3O2BO3 ludwigite
Authors: Leite C. A. F. , Guimarães R. B. , Fernandes J. C. , Continentino M. A. , Paschoal C. W. A. , Ayala A. P. , Guedes I.
Published: August 2002

Raman scattering measurements were carried out for Fe3O2BO3 and Ni2FeO2BO3 ludwigite crystals in the temperature range from 15 to 300 K. At room temperature ludwigite has an orthorhombic structure belonging to space group $D_{2h}^{9}$. Attempts made to record polarized Raman spectra were successful, and we were able to identify most of the phonons belonging to A1g species. A careful analysis of the spectra shows that the observed Raman modes do not exhibit variations either in wavenumber or intensity or both with temperature, indicating that the $D_{2h}^{9}$ phase does not undergo any structural modification in the temperature range investigated. Also, we observed for Fe3O2BO3 ludwigite the appearance of a continuous scattering background in the phonon spectrum for temperatures below 200 K . This background, which is due to electronic transitions between Fe2+ and Fe3+ ions, is related to the charge delocalization effect. Copyright © 2002 John Wiley & Sons, Ltd.
Probing the spontaneous ionization of aromatic amines by adsorption in activated acidic zeolite HZSM‐5
Authors: Moissette Alain , Gener Isabelle , Brémard Claude
Published: August 2002

N, N, N′, N′‐tetramethyl‐p‐phenylenediamine (TMPD) and N, N, N′, N′‐tetramethylbenzidine (TMB) were used as probe molecules to examine their interactions with catalytically active sites generated after thermal treatment at 600 °C under O2 of acidic H6ZSM‐5 zeolite with chemical composition H6(AlO2)6(SiO2)90. The aromatic amines were merely exposed as powders at room temperature under argon to activated acidic H6ZSM‐5 molecular sieve. The course of adsorption and subsequent reactions were monitored by the application of diffuse reflectance, UV–visible absorption, electron paramagnetic resonance (EPR) and Raman scattering spectroscopy. The experimental investigations provided specific evidence of TMPD·+ or TMB·+ radical cations as major durable species and TMB2+ as minor species after complete adsorption. No direct evidence of trapped electrons within the zeolite framework resulting from the ionization was provided by EPR and electronic absorption spectroscopy. The aromatic amines through resonance Raman spectroscopy appear to be a sensitive and specific tool to probe the concentration, strength and accessibility of electron acceptor Lewis acid sites created during thermal treatment under O2. In contrast, no evidence of Brønsted acid sites of H6ZSM‐5 was found during the sorption of TMPD or TMB through the generation of protonated species. Copyright © 2002 John Wiley & Sons, Ltd.
Raman study of phonons in Ga1−xAlxAs
Authors: Lockwood D. J. , Radomski R. , Wasilewski Z.
Published: August 2002

Detailed Raman measurements were performed on the optical phonons in the disordered alloy Ga1−xAlxAs at room temperature. The results obtained are compared with earlier measurements and expressions are given for the Al concentration dependence of the AlAs‐like and GaAs‐like longitudinal and transverse optical modes. Copyright © 2002 John Wiley & Sons, Ltd.
Quantitative assessment of antioxidant properties of natural colorants and phytochemicals: carotenoids, flavonoids, phenols and indigoids. The role of β‐carotene in antioxidant functions
Authors: Beutner Stefan , Bloedorn Britta , Frixel Susanne , Hernández Blanco Inés , Hoffmann Thomas , Martin Hans‐Dieter , Mayer Bernhard , Noack Peter , Ruck Christoph , Schmidt Marcus , Schülke Ines , Sell Stefan , Ernst Hansgeorg , Haremza Sylke , Seybold Günther , Sies Helmut , Stahl Wilhelm , Walsh Robin
Published: August 2002

Reactive oxygen species are potentially damaging molecules. An important function of antioxidants is to intercept harmful triplet states, in order to prevent the formation of singlet oxygen, or to quench singlet oxygen directly. However, antioxidants are also reactive towards other active oxygen species such as the hydroxyl radical, the superoxide anion and the non‐excited oxygen ground state in the presence of radical initiators. It is well known that flavonoids and carotenoids show strong antioxidant properties. Polyenes and carotenoids are the best known among the compounds that quench singlet oxygen by efficient energy transfer. A large number of modified, synthetic analogues and derivatives have been synthesised to prepare even better quenchers than the natural carotenoids. Phenols are also excellent chain‐breaking antioxidants. Recently, many indigoid dyes (including bacterial indigoids) were studied, with the remarkable result that most, but not all, members of this class of chromophores quench singlet oxygen at the diffusion limit and some of them are excellent radical traps. It has been shown in this study that a quantitative assessment of antioxidant properties of flavonoids, carotenoids, phenols and natural indigoids can be achieved using the following three assays: (1) oxygen pressure dependence; (2) peroxide formation; (3) singlet oxygen quenching. Reactivities towards both excited states and ground state radicals can be properly described by these assays. The remarkable role of β‐carotene as an ‘unusual antioxidant’ (Burton GW and Ingold KU,Science224: 569–573 (1984)) in reactions using various oxygen pressures becomes clearer. The so‐called ‘pro‐oxidant effects’ concern primarily the antioxidant itself and its degradation, since no or very little damage to the substrate occurs in this type of experiment. Three main categories of antioxidants may be classified: (1) excellent antioxidants that perfectly quench excited states as well as ground state radicals (eg actinioerythrol, astaxanthin); (2) good antioxidants that strongly inhibit peroxide formation but are less efficient in quenching excited states (eg flavonols, tocopherols) or lead to considerable degradation of the antioxidant itself (eg β‐carotene, lycopene); (3) moderate antioxidants that fail to excel in both reactivities (eg ζ‐carotene, flavone).

© 2001 Society of Chemical Industry
The fermentation of lactulose in rats inoculated with Clostridium paraputrificum influences the activities of liver and intestinal xenobiotic‐metabolising enzymes
Authors: Lhoste Evelyne F , Nugon‐Baudon Lionelle , Lory Sandrine , Meslin Jean‐Claude , Andrieux Claude
Published: August 2002

One of the most recent hypotheses concerning the protective effect of some dietary fibres against colon cancer implicates butyrate. Very few publications have addressed its possible influence on the phase II enzymes and on the bacterial enzymes involved in the enterohepatic recirculation of toxic compounds. We used an original model of monoxenic rats oriented towards the preferential production of butyrate. Fischer male germ‐free rats were mono‐associated with a strain of Clostridium paraputrificum. They were fed either a control diet or a lactulose‐enriched diet for 6 weeks. In the caeco‐colon the specific activities (SAs) of the microsomal enzymes (glutathione‐S‐transferase and UDP‐glucuronosyl‐transferase) were 1.7‐fold those of the control rats. In the intestine and liver the SAs of the phase II enzymes were not altered, nor was the hepatic cytochrome P450. In the caecum of the lactulose‐fed rats the SA of β‐glucuronidase decreased by 27% and that of β‐glucosidase doubled. The chronic consumption of lactulose doubled the total caecal short‐chain fatty acids, and the production of butyrate was enhanced. Since the germ‐free rats behaved differently when fed the same diets, we concluded that the fermentation products of lactulose (and not the lactulose itself) were involved in the effects we describe. The involvement of butyrate in this phenomenon is discussed.

© 2001 Society of Chemical Industry
Expression of CD44v6 in advanced gastric cancer and its relationship to hematogenous metastasis and long‐term prognosis
Authors: Yamaguchi Akio , Goi Takanori , Yu Jiren , Hirono Yasuo , Ishida Makoto , Iida Atsushi , Kimura Toshihisa , Takeuchi Kazuo , Katayama Kanji , Hirose Kazuo
Published: August 2002

Background and Objectives

Variants of CD44 have been proposed to be important in promoting tumor progression and metastasis. We attempted to determine the expression of CD44v6 product in advanced gastric cancer and to evaluate its prognostic value.

Methods

The expression of CD44v6 was analyzed immunohistochemically in advanced gastric cancers using monoclonal antibody, 44‐2V. We investigated the relationship between CD44v6 expression and prognosis in 201 gastric cancer patients.

Results

Ninety‐five (47.3%) of 201 cancer tissues expressed CD44v6. The expression of CD44v6 protein was significantly higher in differentiated, adenocarcinoma than in diffuse type carcinoma. The CD44v6‐positive cancers were more frequently associated with hematogenous metastasis. There was no significant correlation between CD44v6 immunoreactivity, and prognosis among the combined cases. Among patients with differentiated adenocarcinoma, however, the prognosis was significantly poorer in patients with CD44v6‐positive tumors than in those with CD44v6‐negative tumors.

Conclusions

CD44v6 protein may have an important role in hematogenous metastasis, and may be a biologic marker of prognostic significance in differentiated type gastric cancers. J. Surg. Oncol. 2002;79:230–235. © 2002 Wiley‐Liss, Inc.
Status of hyperthermia in the treatment of advanced liver cancer
Authors: Moroz Paul , Jones Stephen K. , Gray Bruce N.
Published: August 2002

The vast majority of patients with malignant liver tumors have inoperable disease. These patients must rely on chemotherapy, radiotherapy, and various locoregional treatments. Although these treatments have demonstrated encouraging response rates, symptom palliation and occasional down staging of tumors, their impact on survival is minor. As a result there has been renewed interest in hyperthermia as a treatment option. This study reviews the current modalities of hyperthermia in terms of clinical results, side effects, limitations, and therapeutic standing. J. Surg. Oncol. 2001;77:259–269. © 2001 Wiley‐Liss, Inc.
Do surgical oncologists achieve lower rates of local‐regional recurrence in node positive breast cancer treated with mastectomy alone?
Authors: Latosinsky Steven , Bear Harry D.
Published: August 2002

Background and Objective:

Adjuvant radiotherapy for node positive breast cancer postmastectomy has been recommended by two previously published randomized controlled trials (RCT). The local‐regional recurrence rates in the control arms, however, were considered by some critics to be excessive (> 25% at 10 years). Inadequate surgery, as evidenced by the low number of axillary nodes reported, may have resulted in the high local‐regional recurrence rates, allowing for the benefits seen with radiotherapy. Fellowship trained surgical oncologists might provide “better quality” surgery, resulting in lower recurrence rates and thus making adjuvant radiotherapy unnecessary. Our objective was to establish the local‐regional control rate postmastectomy in node positive breast cancer patients operated on by surgical oncologists, and to determine if treatment recommendations from previous RCTs are generalizable.

Methods:

Node positive stage IIb and IIIa breast cancer patients treated with mastectomy at the Medical College of Virginia Hospitals by surgical oncologists, without adjuvant radiotherapy, and entered into adjuvant chemotherapy trials between 1978 and 1993 were identified retrospectively. Pathology and follow‐up records were reviewed.

Results:

One hundred and thirty‐seven patients were identified. A median of 18 axillary nodes was reported with a median of 4 positive nodes. The locoregional recurrence at 10‐years was 27% (95% confidence interval, 19–35%).

Conclusion:

Despite some evidence of “better quality” surgery, there was no clinically significant difference in the local‐regional recurrence rate in this case series compared to controls in two previous RCTs. Recommendations for postmastectomy radiotherapy should be considered for node positive breast cancers, even if operated upon by surgical oncologists. J. Surg. Oncol. 2001;78:2–7. © 2001 Wiley‐Liss, Inc.
Adjuvant chemotherapy for osteosarcoma may not increase survival after neoadjuvant chemotherapy and surgical resection
Authors: Berend Keith R. , Pietrobon Ricardo , Moore Joseph O. , Dibernardo Louis , Harrelson John M. , Scully Sean P.
Published: August 2002

Background and Objectives

Osteosarcoma is a primary malignancy of bone. Current therapy includes neoadjuvant chemotherapy, surgery, and postoperative (adjuvant) chemotherapy. Prolonged treatment with chemotherapeutic agents may place patients at increased risk for complications including secondary malignancy. The authors have had promising results with neoadjuvant therapy and surgery alone in the treatment of osteosarcoma. This study retrospectively examines neoadjuvant therapy and surgery alone for the treatment of primary osteosarcoma of bone with no evidence of distant metastases.

Methods

Fifty‐four patients, with localized osteosarcoma of bone received neoadjuvant therapy followed by definitive surgical resection. Thirty‐five patients received chemotherapy after surgery (adjuvant group) and nineteen patients were followed without postoperative chemotherapy (no adjuvant group).

Results

Tumor necrosis was predictive of survival. Kaplan–Meier analysis revealed the use of postoperative chemotherapy was not a predictor of improved outcome. Four patients in the adjuvant therapy group died of secondary malignancy compared with none of the no adjuvant therapy group. Patient age, sex, race, and tumor location were not predictive of survival.

Conclusions

The use of adjuvant chemotherapy in the treatment of localized osteosarcoma of bone did not increase survival after neoadjuvant therapy and definitive surgical therapy. Instead, there was an increased incidence of secondary malignancy after its use. J. Surg. Oncol. 2001;78:162–170. © 2001 Wiley‐Liss, Inc.