bluuebunny/crossref_metadata_2025 huggingface dataset:
Future directions for the analysis of musculoskeletal design and locomotor performance
Authors: Biewener Andrew A.
Published: August 2002

New techniques and conceptual frameworks offer new challenges and exciting opportunities for research on the biomechanics and physiology of vertebrate musculoskeletal design and locomotor performance. Past research based on electromyography and two‐dimensional kinematics has greatly advanced the field of vertebrate functional morphology. Studies using these approaches have revealed much about vertebrate structure and function and have emphasized the importance of incorporating historical and developmental constraint and ecological context. Continued use of these experimental tools, but with greater emphasis on three‐dimensional analysis of body movement, in combination with 3D kinetics and flow visualization of fluid movement past moving organisms, can now take advantage of the considerable advances in computing power and digital video technology. Indeed, surprisingly few detailed 3D analyses of movement for many locomotor modes and differing organisms are presently available. A challenge of 3D analyses will be to reduce the complexity of the data obtained in order to identify general principles of movement and biomechanics. New techniques and approaches for measuring muscle forces and length changes, together with activation patterns and movement, under dynamic conditions of more varied motor behavior are now also available. These provide the opportunity to study the mechanics and physiology of muscle function at greater depth and under more realistic conditions than has been previously possible. The importance of studying intact, behaving organisms under a broader range of locomotor conditions (other than steady state) and in the context of their natural environment remains a critical need for vertebrate biologists. This provides the much‐needed opportunity for placing advances at more cellular and molecular levels into the context of whole organism function. Hence, studies at the organismal level remain paramount. J. Morphol. 252:38–51, 2002. © 2002 Wiley‐Liss, Inc.
Transverse masticatory movements, occlusal orientation, and symphyseal fusion in selenodont artiodactyls
Authors: Hogue Aaron S. , Ravosa Matthew J.
Published: August 2002

Based on extensive experimental work on primates, two masticatory loading regimes have emerged as the likely determinants of mandibular symphyseal fusion—dorsoventral shear and lateral transverse bending (wishboning) (Ravosa and Hylander, 1994; Hylander et al., 1998, 2000). Recently, however, it has been argued that, rather than functioning to strengthen the symphysis during mastication, fusion serves to stiffen the symphyseal joint so as to facilitate increased transverse jaw movements during occlusion (Lieberman and Crompton, 2000). As part of this transverse stiffness model, it has been suggested that taxa with fused symphyses should also exhibit more horizontally oriented occlusal wear facets. Using a series of univariate and bivariate analyses, we test predictions of these three models in a sample of 44 species of selenodont artiodactyls. Consistent with the wishboning and transverse stiffness models, taxa with fused symphyses (camelids) have more horizontally oriented M2 and M2 occlusal wear facets, anteroposteriorly (AP) elongate symphyses, and relatively wider corpora. Contrary to the dorsoventral shear model, camelids do not have relatively deeper corpora (due to greater parasagittal bending). While taxa with ossified symphyses have relatively larger symphysis cross‐sectional areas, this appears to be the byproduct of an increase in AP symphysis length due to greater lateral transverse bending of the mandible. Theoretical consideration of the biomechanics of mastication further suggests that strength, not stiffness, is the critical factor in determining symphyseal ossification. Thus, like anthropoid primates, fusion in selenodont artiodactyls appears to function in resisting increased wishboning stresses arising from an emphasis on transverse occlusal/mandibular movements and loads. J. Morphol. 249:221–241, 2001. © 2001 Wiley‐Liss, Inc.
The sensory epithelium of the tentacles and the rhinophore of Nautilus pompilius L. (cephalopoda, nautiloidea)
Authors: Ruth Peter , Schmidtberg Henrike , Westermann Bettina , Schipp Rudolf
Published: August 2002

Nine intraepithelial ciliated cell types that are presumed to be sensory cells were identified in the epithelium of the pre‐ and postocular tentacles, the digital tentacles, and the rhinophore of the juvenile tetrabranchiate cephalopod Nautilus pompilius L. The morphological diversity and specialization in distribution of the different ciliated cell types analyzed by SEM methods suggest that these cells include receptors of several sensory functions. Ciliated cell types in different organs that show similar surface features were combined in named groups. The most striking cell, type I, is characterized by a tuft of long and numerous cilia. The highest density of this cell type occurs in ciliary fields in the epithelium of the lamellae of the pre‐ and postocular tentacles, in the olfactory pits of the rhinophores, and in the lamellae of four pairs of lateral digital tentacles, but not in the epithelium of the medial digital tentacles. The similar morphological data, together with behavioral observations on feeding habits, suggest that this cell type may serve in long‐distance chemosensory function. The other ciliated cell types are solitary cells with specific spatial distributions in the various organs. Cell types with tufts of relatively short, stiff cilia (types III, IV, VIII), which are distributed in the lateral and aboral areas of the tentacles and at the base of the tentacle‐like process of the rhinophore, are considered to be employed in mechanosensory transduction, while the solitary cells with bristle‐like cilia at the margin of the ciliary fields (type II) and at the base of the rhinophore (type IX) may be involved in chemoreception. Histological investigation of the epithelium and the nerve structures of the different organs shows the proportion and distribution of the sensory pathways.

Two different types of digital tentacles can be distinguished according to their putative functions: lateral slender digital tentacles in four pairs, of which the lowermost are the so‐called long digital tentacles, participate in distance chemoreception, and the medial digital tentacles, whose terminal axial nerve cord may represent a specialized neuromechanosensory structure, appear to have contact chemoreceptive abilities. J. Morphol. 251:239–255, 2002. © 2002 Wiley‐Liss, Inc.
Reproducibility of in vivo metabolite quantification with proton magnetic resonance spectroscopic imaging
Authors: Chard Declan T. , McLean Mary A. , Parker Geoffrey J.M. , MacManus David G. , Miller David H.
Published: August 2002

Purpose

To investigate intra‐ and interscanner in vivo reproducibility of brain metabolite quantification using 1H magnetic resonance spectroscopic imaging (1H‐MRSI) (PRESS localization, TE = 30 msec, voxel volume = 2.3 mL) and the linear combination model (LCModel).

Materials and Methods

One subject had a total of nine scans on three occasions at a single site, and three subjects had single scans at two sites. Coefficients of variation (CVs) were estimated using different statistical models applied to intra‐ and interscanner data; therefore, only qualitative comparisons may be made between results.

Results

CV (intra‐/interscanner) for metabolite quantifications were choline, 12.3%/10.1%; creatine, 9.9%/10.6%; glutamate + glutamine, 15.8%/13.6%; myo‐inositol, 18.5%/14.7%; and N‐acetyl‐aspartate + N‐acetyl‐aspartyl‐glutamate, 6.1%/7.0%. Overall, total intra‐ and intersubject variability was greater than intra‐ and interscanner variability.

Conclusion

When quantifying metabolic concentrations using the methods employed in this study, biological factors contribute a greater proportion to measurement variability than measurement errors. Using this technique, intra‐ and intersite measurement errors are of the same order. J. Magn. Reson. Imaging 2002;15:219–225. © 2002 Wiley‐Liss, Inc.
Biological dosimetry of magnetic resonance imaging
Authors: Guisasola Concepción , Desco Manuel , Millán Olga , Villanueva Francisco J. , García‐Barreno Pedro
Published: August 2002

Purpose

To check the bioeffects of the components of magnetic resonance imaging (MRI). MRI is based on an assumedly harmless interaction between certain nuclei in the body when placed in a strong magnetic field and radio wave fields. There are three key factors actuating on the examining body: a powerful static magnetic field (SMF), magnetic gradient fields (MGFs), and pulsed radiofrequency (RF) radiation.

Materials and Methods

In vitro cells (L‐132 cells) were used as biosensors, and different cellular compounds were used as biomarkers (heat shock proteins [HSPs] and their messenger ribonucleic acids [mRNAs], calcium, and adenosine‐3′,5′‐cyclic monophosphate [cAMP]). The biosensors were placed in the bore of a 1.5‐T MRI machine and the different electromagnetic fields were operated.

Results

HSPs and their mRNAs and cAMP did not respond to SMF, MGFs, or RF radiation. RF radiation increased cytosolic calcium concentration (18%, P < 0.05).

Conclusion

Although MRI procedures do not induce any cellular stress response, it may cause an unfathomable calcium increase in vitro. Although the in vitro experimental conditions are not totally comparable to clinical situations, the usefulness of the in vivo biological dosimetry, circulating leukocytes as biosensors, and HSPs and/or calcium as biomarkers is suggested. J. Magn. Reson. Imaging 2002;15:584–590. © 2002 Wiley‐Liss, Inc.
Analysis of subtraction methods in three‐dimensional contrast‐enhanced peripheral MR angiography
Authors: Huang Yuexi , Webster Christie A. , Wright Graham A.
Published: August 2002

Purpose

To compare the effectiveness of three image subtraction algorithms designed to improve arterial conspicuity in first‐pass contrast‐enhanced magnetic resonance (MR) angiography.

Materials and Methods

Three subtraction methods were analyzed through computer simulations, phantom studies, and clinical studies. These algorithms were: complex subtraction, magnitude subtraction, and maximum intensity projection subtraction.

Results

In high resolution three‐dimensional imaging, maximum intensity projection subtraction generally yields the best background suppression. Complex subtraction is effective in reducing partial volume effects in low resolution imaging. Magnitude subtraction works better in high resolution, low contrast concentration protocols.

Conclusion

Choosing the appropriate subtraction method according to the protocol is helpful in optimizing image quality. J. Magn. Reson. Imaging 2002;15:541–550. © 2002 Wiley‐Liss, Inc.
Myocardial flow reserve parametric map, assessed by first‐pass MRI compartmental analysis at the chronic stage of infarction
Authors: Germain Philippe , Roul Gérald , Baruthio Joseph , Jahn Christine , Coulbois Paul M. , Dumitresco Barbu , Dietemann Jean L. , Bareiss Pierre , Constantinesco A.
Published: August 2002

Regional myocardial flow and flow reserve (MFR) were assessed by compartmental analysis of Gd‐enhanced MRI first‐pass data in 7 patients with atypical chest pain, and in 15 patients with previous transmural myocardial infarction. The FE product (Flow × Extraction coefficient), derived from the modified Kety equation, was measured in regions corresponding to the Tetrofosmine‐SPECT fixed defect and in remote normal regions. The FE product at rest and hyperemic FE product were similar in healed revascularized tissues (70.5 ± 15.6 and 112.5 ± 19.5ml/mn/100g, respectively) and in normal myocardium (76.2 ± 18.3 and 142.2 ± 33.0, respectively). In contrast, the FE index (48.8 ± 15.2 and 60.7 ± 18.0, respectively, P < 0.01 versus the two previous groups) and the MFR (1.27 ± 0.20 vs. 1.91 ± 0.29 in normal regions) were reduced in healed fibrotic tissues when the infarct‐related artery remained occluded. Myocardial flow reserve maps allowed correct identification of regions corresponding to an occluded infarct‐related artery. J. Magn. Reson. Imaging 2001;13:352–360. © 2001 Wiley‐Liss, Inc.
Mass spectrometric analysis of recombinant adenylate cyclase toxin from Bordetella pertussis strain 18323/pHSP9
Authors: Havlícek Vladimír , Higgins LeeAnn , Chen Weibin , Halada Petr , Sěbo Peter , Sakamoto Hiroshi , Hackett Murray
Published: August 2002

The adenylate cyclase toxin–hemolysin (ACT) is a key virulence factor of the whooping cough agent Bordetella pertussis (Bp). The major cytotoxic activity of this 1706‐residue protein consists of its capacity to invade a variety of eukaryotic cells directly across their cytoplasmic membrane and to deliver into cells a catalytic adenylate cyclase domain. This causes impairment of immune effector cells and apoptosis of lung macrophages by uncontrolled conversion of ATP to cAMP. The adenylate cyclase toxin–hemolysin acquires biological activity upon post‐translational amide‐linked palmitoylation of the ϵ‐amino group of lysine 983 (K983) by the accessory fatty acyltransferase, CyaC. However, an additional conserved acylation site can be identified in ACT at lysine 860 (K860) and this residue is palmitoylated when recombinant ACT is produced in Escherichia coli (r‐Ec‐ACT). In this paper we report the double acylation of r‐Bp‐ACT secreted by a recombinant Bp strain 18323/pHSP9. This strain overproduces ACT from an oligocopy plasmid carrying the entire cya locus of Bordetella pertussis 18323. Palmitoylation of both conserved lysines (K860 and K983) of r‐Bp‐ACT expressed by this Bp strain was found. In addition, an error in the deduced protein sequence was identified, with Leu being the real residue at position 1001 and not the Val residue given in the published gene sequence. We also discuss these results in comparison with those from recombinant ACT expressed in E. coli strain K12 XL1‐Blue. The analytical approach for characterization of the fatty acylation of ACT from strain 18323/pHSP9 consisted of multiple proteolytic digestion procedures (trypsin, Asp‐N), microcapillary liquid chromatography/tandem mass spectrometry and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Copyright © 2001 John Wiley & Sons, Ltd.
Electron ionization mass spectra of 3,4‐disubstituted‐1,2,4‐oxa(thia)diazole‐5(4H)‐thione(ones). Substituent effects on the mass spectrometric rearrangement of 3‐aryl‐4‐(p‐tolyl)‐1,2,4‐oxadiazole‐5(4H)‐thiones to the corresponding oxo compounds
Authors: Pihlaja Kalevi , Agirbas Hikmet , Valtamo Pauliina
Published: August 2002

The fragmentation behaviour of ten 3,4‐disubstituted 1,2,4‐oxadiazole‐5(4H)‐thiones and seven 3,4‐disubstituted 1,2,4‐thiadiazole‐5(4H)‐ones studied here confirmed the earlier observations about the partial rearrangement of the former after ionization into the latter before further fragmentation. In the case of eight 3‐(substituted phenyl)‐4‐(p‐tolyl)‐1,2,4‐oxadiazole‐5(4H)‐thiones the fragmentations reflecting the above‐mentioned molecular ion rearrangement show a clear correlation on the substituent σ values. The electron‐withdrawing substituents destabilize the molecular ion, so higher amounts of the rearranged ion [R1NCO]+· are obtained. A good correlation of log[R1NCO]+ against σ was obtained (r = 0.96). Only a satisfactory correlation prevailed for log([R1NCO]+·/[R1NCS]+·) against σ(r = 0.87). Copyright © 2001 John Wiley & Sons, Ltd.
Acetate, propionate and butyrate in plasma: determination of the concentration and isotopic enrichment by gas chromatography/mass spectrometry with positive chemical ionization
Authors: Pouteau Etienne , Meirim Isabelle , Métairon Sylviane , Fay Laurent‐Bernard
Published: August 2002

This study describes a rapid and simple method to determine short‐chain fatty acid (SCFA) concentrations and their isotopic enrichments (M0 + 1 and M0 + 2) in human plasma. Sample preparation involves SCFA extraction and derivatization with 1‐(tert‐butyldimethylsilyl)imidazole. Gas chromatography/mass spectrometry was performed using chemical ionization with ammonia as the reagent gas. Outstanding resolution, excellent linearity and good detection limits were obtained. Inter‐assay and intra‐assay repeatability was below 10% and 3% respectively for SCFA concentration. Inter‐assay repeatability was below 5%, 4%, 6%, and 14% for isotopic enrichment determination of [1‐13C]acetate and [1,2‐13C2]acetate, [1‐13C]propionate and [1‐13C]butyrate respectively, with intra‐assay being below 6%. Such SCFA concentrations and isotopic enrichments were determined in the plasma of rats infused with a 13C‐labeled SCFA. The turnovers of acetate, propionate and butyrate in rats were 19 µmol kg−1 min−1, 2.6 µmol kg−1 min−1, 0.3 µmol kg−1 min−1 respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Environmental applications of membrane introduction mass spectrometry
Authors: Ketola Raimo A. , Kotiaho Tapio , Cisper Mary E. , Allen Todd M.
Published: August 2002

The purpose of this review is to highlight the versatility of membrane introduction mass spectrometry (MIMS) in environmental applications, summarize the measurements of environmental volatile organic compounds (VOCs) accomplished using MIMS, present developments in the detection of semi‐volatile organic compounds (SVOCs) and forecast possible future directions of MIMS in environmental applications. Copyright © 2002 John Wiley & Sons, Ltd.
Subcellular localisation of the X protein in HBV infected hepatocytes
Authors: Hoare Jonathan , Henkler Frank , Dowling Jason J. , Errington William , Goldin Robert D. , Fish David , McGarvey Michael J.
Published: August 2002

Hepatitis B virus X protein (HBx) is a multifunctional protein that exerts its effects primarily by acting as a transcriptional transactivator of viral and multiple host cell genes. HBx is thought to be essential for maintaining viral replication and has been implicated in the development of hepatocellular carcinoma in patients chronically infected with hepatitis B virus. Very little is known about its functional mechanisms and although interactions with several nuclear and cytoplasmic proteins have been demonstrated in vitro, there is no clear consensus as to where HBx localises in infected hepatocytes. In this study, the expression and intracellular distribution of HBx were examined in human liver biopsies using an anti‐HBx rabbit polyclonal antiserum. HBx was detected in a high proportion (69%) of samples from patients with chronic HBV infection. Detection of HBx correlated with the absence of cirrhosis and the presence of serum e‐antigen. HBx was detected predominantly in the cytoplasm; however, it was also found in the nuclei of up to 20% of positively stained hepatocytes, either exclusively nuclear or localised both in the nucleus and cytoplasm within the same cell. Furthermore, the intracellular distribution of HBx was analysed in transfected Huh‐7 cells by confocal microscopy, using the monoclonal antibody 16F1. In these experiments, a substantial nuclear detection was confirmed in a significant proportion of HBx expressing cells. The data indicate a high functional significance of nuclear HBx, consistent with the concept that transactivation may involve interactions with nuclear proteins. J. Med. Virol. 64:419–426, 2001. © 2001 Wiley‐Liss, Inc.
An antigen fragment encompassing the AD2 domains of glycoprotein B from two different strains is sufficient for differentiation of primary vs. recurrent human cytomegalovirus infection by ELISA
Authors: Rothe Markus , Pepperl‐Klindworth Sandra , Lang Dieter , Vornhagen Rolf , Hinderer Walter , Weise Kerstin , Sonneborn Hans‐H. , Plachter Bodo
Published: August 2002

Primary human cytomegalovirus (HCMV) infection during pregnancy is a frequent cause of fatal damage in populations with low prevalence of HCMV. Differentiation of primary vs. recurrent HCMV infection is an important issue in prenatal counseling. Antibodies specific for viral glycoproteins become detectable only with considerable delay with relation to HCMV infection or IgG seroconversion. Thus, lack of glycoprotein specific (gp‐specific) antibodies can serve as a convenient indicator to identify those pregnant women that bear an elevated risk for HCMV transplacental transmission and fetal sequelae. In the opposite case, presence of gp‐specific antibodies virtually excludes HCMV primary infection several weeks before sampling. However, no standardized screening assay for HCMV gp‐specific antibodies had been available thus far. For this reason, an ELISA based on procaryotically expressed fragments of HCMV glycoprotein B (gB; gpUL55) was developed. Small fragments of gB from two different laboratory strains, encompassing the antigenic domain 2 (AD2) sufficed for sensitive and specific detection of gp‐specific antibodies. The gB‐ELISA titers correlated with titers of virus neutralizing antibodies in serum samples from primary or recurrent HCMV infections. Seroconversion kinetics of the gB‐ELISA in samples from patients with primary HCMV infection closely paralleled the delay in seroconversion of gp‐specific antibodies as determined by neutralization assay. Thus this assay provides a diagnostic tool that is easy to perform and can significantly add to available methods for the timely identification of primary HCMV infection during pregnancy. In addition, the gB‐ELISA may be helpful in other clinical settings for the differentiation of primary HCMV infection from diseases caused by other pathogens. J. Med. Virol. 65:719–729, 2001. © 2001 Wiley‐Liss, Inc.
A novel method for determination of the maximum stable feedback level in laser diodes
Authors: Pierce Iestyn , Rees Paul , Spencer Paul S. , Alan Shore K.
Published: August 2002

A simple method is presented for determining the minimum feedback level required for the onset of instability and chaos in semiconductor laser diodes. Using this method, the positions of the pair of dominant system poles in the s‐plane are found for varying levels of feedback. This analysis determines the feedback level required to send the system unstable. The results are applicable for both long and short external cavities. The method is ideally suited to the prediction of system stability from measurements of microwave modulation response or relative intensity noise (RIN) spectrum, since it only requires knowledge of the natural frequency and damping frequency of the dominant s‐plane poles of the laser diode without optical feedback. Copyright © 2001 John Wiley & Sons, Ltd.
Re‐evaluation of phencyclidine low‐affinity or “non‐NMDA” binding sites
Authors: Hirbec Hélène , Mausset Anne‐Laure , Kamenka Jean Marc , Privat Alain , Vignon Jacques
Published: August 2002

TCP and its derivative gacyclidine (± GK11) are high‐affinity non‐competitive antagonists of N‐methyl‐D‐aspartate (NMDA) receptors (NMDARs) and as such exhibit significant neuroprotective properties. These compounds also bind with a low affinity to binding sites whose pharmacological profiles are different from that of NMDARs. With the intention to develop new strategies of neuroprotection, we found it mandatory to investigate whether 1‐[1‐(2‐thienyl)cyclohexyl]piperidine (TCP) and gacyclidine low‐affinity sites are similar. The effects of several drugs selective for either NMDARs or the [3H]TCP low‐affinity site (or PCP3 site) on (+), (−)[3H]GK11 and [3H]TCP specific binding were investigated. Competition experiments on cerebellum homogenates revealed substantial differences between the pharmacological profiles of the PCP3 site and that of gacyclidine's enantiomers low‐affinity sites. Under experimental conditions preventing the interaction of the radioligands with NMDARs, the autoradiographic study showed, however, that the distributions of both [3H]TCP and (−)[3H]GK11 specific binding were similar. The specific labelling was low and uniform in telencephalic structures, whereas in the cerebellum it was higher in the molecular than in the granular layer. Finally, the analysis of competition experiments performed on tissues slices demonstrated that PCP3 selective ligands were unable to prevent [3H]TCP or (−)[3H]GK11 binding to “non‐NMDA” binding sites. As a whole, our data suggest that: (1) the different pharmacological profiles of [3H]TCP and [3H]gacyclidine enantiomers on low‐affinity sites are due to their selectivity for specific NMDARs subpopulations; (2) the pharmacological isolation of TCP and gacyclidine “non‐NMDA” binding sites is the most appropriate way to further study the low‐affinity component of their specific binding. Obtaining reliable and specific pharmacological tools for those binding sites is of particular interest, since it is likely that they play a substantial role in the low neurotoxicity, and therefore tolerability, of gacyclidine, a new neuroprotective drug currently evaluated in clinical trials for the treatment of brain and spinal cord injuries. © 2002 Wiley‐Liss, Inc.
Stem cell repair of central nervous system injury
Authors: Cao Qilin , Benton Richard L. , Whittemore Scott R.
Published: August 2002

Neural stem cells (NSCs) have great potential as a therapeutic tool for the repair of a number of CNS disorders. NSCs can either be isolated from embryonic and adult brain tissue or be induced from both mouse and human ES cells. These cells proliferate in vitro through many passages without losing their multipotentiality. Following engraftment into the adult CNS, NSCs differentiate mainly into glia, except in neurogenic areas. After engraftment into the injured and diseased CNS, their differentiation is further retarded. In vitro manipulation of NSC fate prior to transplantation and/or modification of the host environment may be necessary to control the terminal lineage of the transplanted cells to obtain functionally significant numbers of neurons. NSCs and a few types of glial precursors have shown the capability to differentiate into oligodendrocytes and to remyeliate the demyelinated axons in the CNS, but the functional extent of remyelination achieved by these transplants is limited. Manipulation of endogenous neural precursors may be an alternative therapy or a complimentary therapy to stem cell transplantation for neurodegenerative disease and CNS injury. However, this at present is challenging and so far has been unsuccessful. Understanding mechanisms of NSC differentiation in the context of the injured CNS will be critical to achieving these therapeutic strategies. © 2002 Wiley‐Liss, Inc.
Strategies for neuroprotection against L‐trans‐2,4‐pyrrolidine dicarboxylate‐induced neuronal damage during energy impairment in vitro
Authors: García Octavio , Massieu Lourdes
Published: August 2002

Increased levels of extracellular excitatory amino acids and failure of energy metabolism are two conditions associated with brain ischemia. In the present study we have combined the simultaneous inhibition of glutamate uptake and mitochondrial electron transport chain to simulate neuronal damage associated with brain ischemia. Results show that cerebellar granule neurons are not vulnerable to transient glutamate uptake inhibition by L‐trans‐pyrrolidine‐2,4‐dicarboxylate (PDC) despite the increase in the extracellular concentration of glutamate, unless they are simultaneously exposed to the mitochondrial toxins 3‐nitropropionic acid (3‐NP) or sodium azide. Cell damage was assessed by light microscopy observation, by reduction of 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT), and by the fluorescent markers for live and dead cells, calcein and ethidium homodimer, respectively. The protective effect of alternative energy substrates, such as pyruvate, acetoacetate, and β‐hydroxybutyrate against PDC‐induced neuronal death during 3‐NP exposure was studied and compared to the effects of the antioxidant vitamin E, the spin trapper α‐phenyl‐N‐tert‐butylnitrone (PBN), voltage‐dependent calcium channel antagonists, and glutamate receptor antagonists. Results show that neuronal damage can be efficiently prevented in the presence of pyruvate and the N‐methyl‐D‐aspartate (NMDA) receptor antagonist MK‐801, whereas the non‐NMDA receptor antagonist NBQX, acetoacetate, vitamin E, and PBN showed partial protection. In contrast, β‐hydroxybutyrate and voltage‐dependent calcium channels blockers did not show any protective effect at the concentrations tested. J. Neurosci. Res. 64:418–428, 2001. © 2001 Wiley‐Liss, Inc.
Mechanisms of cell death in primary cortical neurons and PC12 cells
Authors: Reimann‐Philipp Ulrich , Ovase Roma , Weigel Paul H. , Grammas Paula
Published: August 2002

Increasing evidence suggests that the regulation of neuronal cell death is complex. In this study we compared the neurotoxic effects of tumor necrosis factor‐α (TNFα), nitric oxide, and thrombin on primary rat cortical cell cultures and the neuronal PC12 cell line. Release of lactate dehydrogenase (LDH) and the intracellular accumulation of nucleosomes were used as indicators of necrosis and apoptosis, respectively. There was significant LDH release in both neuronal cell types, however, the pattern of LDH release was variable and agonist‐dependent. In response to the nitric oxide generator, sodium nitroprusside (SNP), cortical cells exhibited pronounced LDH release and dramatic morphologic changes, whereas in differentiated PC12 cells, TNFα evoked release of LDH with no associated morphologic changes. Both neuronal cell types, but not undifferentiated PC12 cells, responded to TNFα and thrombin with increased apoptosis. Caspase inhibition, but not antioxidant treatment, reduced nucleosome accumulation in primary cortical cells, but not in differentiated PC12 cells. In the differentiated PC12 cells, caspase inhibition reduced TNFα‐mediated LDH release, but not nucleosome accumulation. These data suggest mechanisms involved in neuronal cell death utilize multiple pathways that vary depending on the neurotoxic insult and are also influenced by subtle differences among neuronal cell phenotypes. J. Neurosci. Res. 64:654–660, 2001. © 2001 Wiley‐Liss, Inc.
Cholinergic modulation of synaptic physiology in deep layer entorhinal cortex of the rat
Authors: Cheong Mi Young , Yun Sung Hwan , Mook‐Jung Inhee , Joo Insoo , Huh Kyoon , Jung Min Whan
Published: August 2002

We have recently shown that cholinergic effects on synaptic transmission and plasticity in the superficial (II/III) layers of the rat medial entorhinal cortex (EC) are similar, but not identical, to those in the hippocampus (Yun et al. [2000] Neuroscience 97:671–676). Because the superficial and deep layers of the EC preferentially convey afferent and efferent hippocampal projections, respectively, it is of interest to compare cholinergic effects between the two regions. We therefore investigated the physiological effects of cholinergic agents in the layer V of medial EC slices under experimental conditions identical to those in the previous study. Bath application of carbachol (0.5 μM) induced transient depression of field potential responses in all cases tested (30 of 30; 18.5% ± 2.3%) and rarely induced long‐lasting potentiation (only 3 of 30; 20.4% ± 3.2% in successful cases). At
5 μM, carbachol induced transient depression only (20 of 20, 48.9% ± 2.8%), which was blocked by atropine
(10 μM). Paired‐pulse facilitation was enhanced during carbachol‐induced depression, suggesting presynaptic action of carbachol. Long‐term potentiation (LTP) could be induced in the presence of 10 μM atropine by theta burst stimulation, but its magnitude was significantly lower (9.1% ± 4.7%, n = 15) compared to LTP in control slices (22.4% ± 3.9%, n = 20). These results, combined with our previous findings, demonstrate remarkably similar cholinergic modulation of synaptic transmission and plasticity across the superficial and deep layers of EC. J. Neurosci. Res. 66:117–121, 2001. © 2001 Wiley‐Liss, Inc.
Precipitation seasonality in eastern and southern coastal Spain
Authors: Sumner G. , Homar V. , Ramis C.
Published: August 2002

The nature of the seasonality of precipitation in eastern and southern coastal Spain (including both the Mediterranean and the far southwestern Atlantic provinces) is examined using monthly precipitation values available for 410 sites for the period 1964–1993. Important contrasts are illustrated between eastern (Mediterranean) and southern (Atlantic) areas. In the east, seasonality is more subdued due to incursions of fronts from the north at all times of the year. In the far south, the months of July and August are almost completely dry, but the period October–February is wet due to incursions of active Atlantic frontal systems. In central areas (Almería, Murcia, Alacant, València and the Illes Balears) the significance of extensive severe thunderstorm development during September and October produces an autumn peak in precipitation amount. The spatial variation of precipitation seasonality is further examined using the seasonality index derived by Walsh and Lawler (Walsh PD, Lawler DM. 1981. Rainfall seasonality: description, spatial patterns and change through time. Weather 36: 201–208). Trends of this index through the 30‐year period are identified for some areas using linear regression on 5‐year running means of the index, and indicate that seasonality is increasing in the south (Andalucía), around the uplands of Catalunya (near Lleida) in the east, and in a few smaller areas in between. In the south, the increase in seasonality is due to a greater concentration of precipitation during the cooler part of the year, so that the period January–March is becoming drier, but October–December, wetter. The overall cool season precipitation remains much as for the present, though some evidence for drying is indicated for Málaga, Jaén and Granada. Precipitation in the normally dry month of July is also increasing. In upland Catalunya, there are indications of a greater concentration of cool season precipitation, with, notably, higher amounts in October and some evidence of warm season drying, notably in June. Copyright © 2001 Royal Meteorological Society
Lagged teleconnections between snow depth in northern Eurasia, rainfall in Southeast Asia and sea‐surface temperatures over the tropical Pacific Ocean
Authors: Ye Hengchun , Bao Zhenhao
Published: August 2002

This study shows that above‐(below‐)normal winter snow depth over European Russia and corresponding below‐(above‐)normal snow depth over central Siberia is associated with reduced (increased) summer monsoon rainfall over southern and western India and eastern Pakistan, and above‐(below‐)normal sea‐surface temperatures (SSTs) over the eastern and central tropical Pacific Ocean during the following winters. The connection is slightly stronger when snow depth over European Russia is above normal than below normal. These results are derived from an examination of 60 years (1936–1995) of winter snow depth data and SSTs, and 45 years (1951–1995) of summer precipitation records. The results of this study suggest that winter snow depth over the western rather than the eastern portion of Eurasia is critical to Southeast Asian summer monsoon rainfall and eastern tropical Pacific SSTs during the following seasons. Copyright © 2001 Royal Meteorological Society
Resonance Raman marker bands of β-octahalogeno-meso-tetraarylmetalloporphyrins
Authors: HALVORSEN INGAR , STEENE ERIK , GHOSH ABHIK
Published: August 2002

Soret-excited resonance Raman (RR) spectra are reported for some 40 nonplanar metalloporphyrin complexes. These include (i) copper β-octabromo-meso-tetra(para-X-phenyl)porphyrins, Cu [ Br 8 T (p- X - P ) P ] ( X = CH 3, H , F , CF 3, NO 2); (ii) copper β-octachloro-meso-tetra(para-X-phenyl)porphyrins, Cu [ Cl 8 T (p- X - P ) P ] ( X = H , CF 3); (iii) zinc β-octabromo-meso-tetraphenylporphyrin, Zn [ Br 8 TPP ], and zinc β-octasubstituted meso-tetrakis(pentafluorophenyl)porphyrins, Zn [ Y 8 TPFPP ] ( Y = CH 3, Cl , Br ); (iv) nickel β-octabromo-meso-tetra(para-X-phenyl)porphyrins, Ni [ Br 8 T (p- X - P ) P ] ( X = CH 3, H , F , Br , COOMe , CF 3, NO 2), with and without bis-ligated axial pyridine and imidazole ligands; (v) nickel β-octachloro-meso-tetra(para-X-phenyl)porphyrins, Ni [ Cl 8 T (p- X - P ) P ] ( X = CH 3, H , F , COOMe , CF 3, NO 2), again with and without bis-ligated axial pyridine ligands; and (vi) nickel octaethyltetraphenylporphyrin, Ni [ OETPP ], and palladium octaethyltetraphenylporphyrin, Pd [ OETPP ]. The spectra lead to the following conclusions. For a particular nonplanar porphyrin ligand, the high-frequency RR marker bands ν2 and ν4 downshift with increasing size of the coordinated metal ion, including a low- to high-spin transition for nickel porphyrins. In contrast, for a particular coordinated metal ion, these frequencies downshift with increasing nonplanarity of the porphyrin ligand, which in turn correlates with decreasing metal–nitrogen distances or the 'core size'. Similar results were also found for β-octaalkyl-meso-tetraphenylmetalloporphyrins by Shelnutt and coworkers. Thus, it appears that this complicated multiple-valued core size dependence of the high-frequency RR marker bands may be a generally shared property of all saddled metalloporphyrins. Variations in the electronic character of the metalloporphyrins resulting from variations in the para-substituents on meso-aryl groups do not result in significant shifts in the RR marker bands. The symmetric C meso – C phenyl stretching frequency (ν1) at approximately 1240 cm-1 is prominent in all the RR spectra except those of the low-spin Ni saddled porphyrins, for which they are relatively suppressed, and possible electronic-structural implications of this effect are discussed. In the low-frequency regions of the RR spectra of the compounds studied, the strongest band is roughly around 300 cm-1 and appears to be relatively safely assignable as γ16, a pyrrole tilting mode that strongly resembles the saddling mode in terms of atomic displacements.
Evaluation studies of technetium-99m-porphyrin (T3,4BCPP) for tumor imaging
Authors: SUBBARAYAN MURUGESAN , SHETTY S. J. , SRIVASTAVA T. S. , NORONHA O. P. D. , SAMUEL A. M.
Published: August 2002

A water-soluble porphyrin, 5,10,15,20-tetrakis[3,4-bis(carboxymethyleneoxy)phenyl] porphyrin (T3,4BCPP), was successfully labeled with 99 m Tc and biodistribution studies were performed in Wistar rats. Scintiimaging and in vivo distribution studies were also carried out in C 6-gliomas and mammary tumor-bearing animals using a gamma camera. Tumor-to-muscle (T/M) ratios were calculated and compared with those obtained with the known tumor-seeking radiopharmaceuticals 99 m Tc (V)- DMSA (DMSA = dimercaptosuccinic acid), 99 m Tc -citrate and 201 TlCl . In the case of C 6-gliomas, the ratios were 4.2, 2.2, 4.00 and 3.0; while in the case of C 3 H / J mammary tumor, the ratios were 9.4, 8.8, 8.1 and 8.5 for T3,4BCPP, 99 m Tc ( V )- DMSA , 99 m Tc -citrate and 201 TlCl , respectively. Similar studies were carried out in N-methyl-N-nitrosourea ( NMU )-induced mammary tumor animals and the T/M ratios obtained were 5.9, 2.0, 5.3 and 3.3 for T3,4BCPP, 99 m Tc ( V )- DMSA , 99 m Tc -citrate and 201 TlCl , respectively. The radiolabeled photosensitizer could perhaps be used to detect cancer non-invasively and could even prove useful in monitoring the progression/regression of tumors before, during, and after chemotherapy, radiation therapy or photodynamic therapy (PDT).
Response of chironomids to Late Quaternary environmental change in the Taitao Peninsula, southern Chile
Authors: Massaferro Julieta , Brooks Stephen J.
Published: August 2002

An Erratum has been published for this article in Journal of Quaternary Science 17(7) 2002, 721.

There is conflicting evidence concerning the extent and timing of late Quaternary climate variability in southern South America and how this may be linked to climate change in the Northern Hemisphere. Critical unresolved questions include whether or not a cool period occurred in southern South America during the Younger Dryas Chronozone (YDC) (11 000–10 000 14C yr BP; 13 000–11 200 yr BP), and the timing of wet and dry phases during the Holocene. To date most evidence is from glacial, pollen and beetle records but, in an attempt to resolve these questions, we have used chironomid midges as an independent proxy in one of the first studies of its kind in Patagonia. We investigated the dynamics of midge assemblages during the Late‐glacial and Holocene at Lago Stibnite on the Taitao Peninsula, southern Chile (46°S). Changes in the midge assemblage suggest that the climate may have become cooler and drier during the YDC. During the Holocene there were cyclical changes in the midge assemblage that may have been in response to trophic change and/or to changes in precipitation when conditions appear to have been drier than today at 9400–6300 14C yr BP and 2400–1600 14C yr BP. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectroscopy of kaolinites using different excitation wavelengths
Authors: Frost Ray L. , Fredericks Peter M. , Kloprogge J. Theo , Hope Greg A.
Published: August 2002

The Raman spectra of both low‐ and high‐defect kaolinites in the hydroxyl stretching and low‐wavenumber region were obtained with excitation at three visible wavelengths of 633, 514 and 442 nm and a UV wavelength of 325 nm. The UV‐excited spectra were comparable to those excited by the visible wavelengths. The Raman spectra show hydroxyl stretching bands at 3621 cm−1 attributed to the inner hydroxyl, at 3692 and 3684 cm−1 attributed to the longitudinal and transverse optic modes of the inner surface hydroxyls and at 3668 and 3653 cm−1 assigned to the out‐of phase vibrations of the inner surface hydroxyls. Two bands were observed in the spectral profile at 3695 cm−1 for the high‐defect kaolinite at 3698 and 3691 cm−1 and were assigned to TO/LO splitting. An increase in relative intensity of the transverse optic mode is observed with decrease in laser wavelength. The intensity of the out‐of‐phase vibrations at 3668 and 3653 cm−1 of the inner surface hydroxyls shows a linear relationship with the longitudinal and transverse optic modes. In the low‐wavenumber region excellent correlation was found between the experimentally determined and the calculated band positions. Copyright © 2001 John Wiley & Sons, Ltd.
Vibrational spectroscopy of polymeric biomaterials
Authors: Taddei Paola , Tinti Anna , Fini Giancarlo
Published: August 2002

This review highlights the potential of vibrational spectroscopy for investigating the molecular structure of some polymeric materials used in biomedical applications in relation to their biocompatibility. Many types of polymers are used for biomedical purposes; depending on the application, bioresorbable or non‐bioresorbable (semi‐crystalline or amorphous) polymers are used. Among bioresorbable polymers, we focused on homopolymers and copolymers based on poly(lactic acid), poly(glycolic acid) and poly(ε‐caprolactone). Being a nondestructive technique, Raman spectroscopy proved particularly suitable for evaluating the molecular structure and crystallinity of bioresorbable polymers and their degradation products. For various biomedical applications, non‐degradable semi‐crystalline polymers have been widely employed; in this class of polymers, we concentrated on ultra‐high molecular weight polyethylene (UHMWPE) used in orthopaedic implants (total hip and knee joints). Vibrational spectroscopy appeared particularly suitable in studying the oxidation and crystallinity of UHMWPE. Copyright © 2001 John Wiley & Sons, Ltd.
Temperature‐dependent Raman and infrared spectra of nucleosides. II—Cytidine
Authors: Lee S. A. , Li J. , Anderson A. , Smith W. , Griffey R. H. , Mohan V.
Published: August 2002

Raman and infrared (IR) spectra were recorded for crystalline cytidine samples at 298, 160, 75 and 10 K. Data were taken over the spectral range 20–4000 cm−1. The wavenumbers of most vibrational modes were found to increase as the temperature was lowered, but several peaks near 3000 cm−1 showed the opposite trend. A number of peaks split into multiplets at low temperature. No evidence was found of any structural phase transitions in this temperature range. Plausible assignments of all main observed features are suggested. Copyright © 2001 John Wiley & Sons, Ltd.
Multi‐skilled and multi‐faceted: a comparative survey of UK and Australian information systems and technology professionals
Authors: Kakabadse Andrew , Korac‐Kakabadse Nada
Published: August 2002

A comparative study of over 250 UK and Australian information systems and technology (IS/IT) managers and professionals reported in this paper shows that the Australian contingent exhibit a greater capability for being multi‐skilled and multi‐faceted than their UK counterparts.

The IS/IT function is greater represented on the boards of UK companies than Australian companies.

Both groups display a substantial capacity for working across matrix structures, driving through change and influencing line management on how to best utilise information systems in the enterprise.

Copyright © 2001 John Wiley & Sons, Ltd.
Using multinational strategic alliance negotiations to help ensure alliance success: an entrepreneurial orientation
Authors: Mockler Robert J. , Gartenfeld Marc E.
Published: August 2002

This paper discusses the strategic importance of the negotiation phase of multinational strategic alliance development. The focus is on the potential partner negotiation process that occurs prior to the signing of the alliance deal.

It explores ways in which negotiations can be effectively used to substantially improve the chances of success by providing practical guidelines that are useful for multinational managers.

The wide variety of activities and demands involved involves a contingent entrepreneurial management process that is examined here.

Copyright © 2001 John Wiley & Sons, Ltd.
Critical factors for enhancing creativity
Authors: McFadzean Elspeth
Published: August 2002

This article explores five factors that can influence creative thinking: namely Judgement: Freewheeling: Association: Stimulation and Expression.

These factors are used to develop a framework in order to categorize, compare and contrast different creative problem‐solving techniques.

The three categories developed in the framework are paradigm‐preserving techniques, paradigm‐stretching techniques and paradigm‐breaking techniques.

A number of practical implications are then presented including training, teambuilding and the reduction of apprehension and cognitive inertia.
The experience of forming business relationships in tourism
Authors: Watkins Mike , Bell Barry
Published: August 2002

This study examines the formation of business relationships among tourism organisations. A phenomenographic study conducted with 25 managers drawn from regional tourism organisations in Queensland, Australia revealed three qualitatively different but interrelated ways of experiencing relationships: as competition, co‐operation and collaboration. Differences among experiences were accounted for by the way managers defined the meanings of several dimensions common to each experience. The results suggest managers' experiences can be developmentally ordered on a continuum of relationships that demonstrate progressively more complex and inclusive approaches to forming relationships. Copyright © 2001 John Wiley & Sons, Ltd.
Copper and Iron: A landmark connection of two essential metals
Authors: Harris Edward D.
Published: August 2002

Research in the past millennium gave us formidable advances in the fields of Cu nutrition, biochemistry, animal and human health. Insights into Cu‐Fe interactions highlighted much significant advancement. The recognition that Cu was an essential mineral for Fe metabolism and hemoglobin biosynthesis traces back to a paper by Hart et al. at Wisconsin appearing in the first third of the century. This observation came at a time when the only known function of Cu was that of a constituent of hemocyanin pigment in some mollusks and crustacea. The Wisconsin group's studies were preceded by McHargue's work, which introduced glass‐lined cages to study trace mineral function, and in so doing, provided the first experimental evidence for Mn, Cu, and Zn essentiality. Here, we review the details of the experiments by Hart et al. that led to the discovery of copper's interconnection with Fe and important papers that have since given mechanistic clarity to the interaction. J. Trace Elem. Exp. Med. 14:207–210, 2001.