bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular structure retention relationships in comprehensive two‐dimensional gas chromatography
Authors: Marriott Philip J. , Massil Tracy , Hügel Helmut 
Published: November 2004

AbstractComprehensive two‐dimensional gas chromatography (GC×GC) offers new opportunities to develop relationships between molecular structure and retentions in the two dimensional (2D) separation space defined by the GC×GC retention in each dimension. Whereas single dimension GC provides only one retention property for a solute, and hence the specific relationship between retention and chemical property is not readily apparent or derivable, the 2D presentation of compounds in GC×GC provides a subtle and exquisite correlation of chemical property and retention unlike any other GC experiment. The ‘orthogonality’ of the two separation dimensions is intimately related to the manner in which different separation mechanisms, available through use of two dissimilar phases, are accessible to the different chemical compounds or classes in a sample mixture, and indeed the specific chemical classes present in the sample. The GC×GC experiment now permits various processes such as chemical decompositions, molecular interconversions, various non‐linear chromatography effects, and processes such as slow reversible interactions that may arise with stationary phases or in the injector or column couplings, to be identified and further investigated. Here, we briefly review implementation of the GC×GC method, consider the molecular selectivity of GC×GC, and highlight a selection of molecular processes that can be probed by using GC×GC.
How to utilize the true performance of monolithic silica columns
Authors: Ikegami Tohru , Dicks Edith , Kobayashi Hiroshi , Morisaka Hironobu , Tokuda Daisuke , Cabrera Karin , Hosoya Ken , Tanaka Nobuo 
Published: November 2004

AbstractWays of utilizing the true separation efficiency of monolithic silica (MS) columns were studied. The true performance of MS columns, both regular‐sized (rod‐type clad with PEEK resin, 4.6 mm ID, 10 cm) and capillary sized (in 100 or 200 μm fused silica capillary, 25–140 cm) was evaluated by calculating the contribution of extra‐column effects. HETP values of 7–9 μm were observed for solutes having retention factors (k values) of up to 4 for rod columns and up to 15 for a capillary column. The high permeability of MS columns allowed the use of long columns, with several connected together in the case of rod columns. Narrow‐bore connectors gave good results. Peak variance caused by a column connector ranges from 50 to 70% of that caused by one rod‐type column for up to three connectors or four columns in 80% methanol, but the addition of a 4th or 5th connector to add a 5th and 6th column, respectively, caused a much greater increase in peak variance, especially for long‐retained solutes, which is greater than the variance caused by one rod column. Rod columns seem to show slightly lower efficiency at a pressure higher than 10 MPa or so. The use of acetonitrile‐water as a mobile phase better preserved the ability of individual rod columns to generate up to 100,000 theoretical plates with 14 columns connected. Methods for eliminating extra‐column effects in micro‐HPLC were also studied. Split injection and on‐column detection resulted in optimum performance. A long MS capillary measuring 140 cm produced 160,000 theoretical plates. The column efficiency of a capillary column was not affected by the pressure, showing advantages over the rod columns that exhibited peak broadening caused by connectors and pressure.
In vivo activation of gelatinase B/MMP‐9 by trypsin in acute pancreatitis is a permissive factor in streptozotocin‐induced diabetes
Authors: Descamps Francis J , Martens Erik , Ballaux Florence , Geboes Karel , Opdenakker Ghislain 
Published: November 2004

AbstractMatrix metalloproteinases, in particular gelatinase B/MMP‐9, are key mediators in autoimmune diseases like multiple sclerosis and rheumatoid arthritis, but their pathogenic roles in diabetes are not well established. Gelatinase B has previously been shown to be upregulated in pancreas tissue from patients with acute and chronic pancreatitis and was suggested to exacerbate diabetes by cleaving insulin. In this study, the role of gelatinase B in diabetes was investigated using two streptozotocin‐induced animal models of type I diabetes. In both a hyperacute and a subacute model, gelatinase B upregulation was found to be associated with disease activity. However, gelatinase B deficiency did not significantly protect against diabetes development, and wild‐type and gelatinase B‐deficient animals behaved similarly in terms of β‐cell apoptosis or necrosis. The fact that gelatinase B was found almost exclusively as the inactive pro‐enzyme in most of the streptozotocin‐induced diabetic animals may explain the lack of a gelatinase B effect. On the contrary, gelatinase B was completely activated in a minority (15%) of wild‐type animals. This coincided with exocrine pancreatic inflammation, as revealed by the presence of active trypsin. The discovery of in vivo activation of progelatinase B by trypsin in acute pancreatitis is extended in a model of caerulein‐induced pancreatitis. In the latter model, trypsinogen activation is systematically achieved and gelatinase B is found in its active form. In conclusion, gelatinase B itself is not a causative factor but, when activated by endogenous trypsin, is a permissive factor for insulin degradation and diabetes. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The relationship of VEGF and PGE2 expression to extracellular matrix remodelling of the tenosynovium in the carpal tunnel syndrome
Authors: Hirata Hitoshi , Nagakura Takeshi , Tsujii Masaya , Morita Akimasa , Fujisawa Kohzo , Uchida Atsumasa 
Published: November 2004

AbstractTenosynovial thickening within the confined space of the carpal tunnel is thought to be the cause of the carpal tunnel syndrome (CTS). However, little is known about the pathological mechanism of tenosynovial thickening. In this study, the role of prostaglandin E2 (PGE2) and vascular endothelial growth factor (VEGF) (two representative molecules that can induce oedema by increasing vascular permeability) was analysed in CTS by using immunohistochemistry and enzyme‐linked immunosorptive assay (ELISA). Expression of these molecules was compared with the patients' clinical histories and a temporary increase in production of these molecules was found in cells within the vessels and synovial lining during the intermediate phase of the syndrome when the histology of the tenosynovium changes from oedematous to fibrotic. Statistical analysis clearly demonstrated that there is a close correlation between the expression of PGE2 and VEGF. Furthermore, immunohistochemical analysis with anti‐proliferating cell nuclear antigen (PCNA) revealed that the area with distinct VEGF expression closely matched the area where endothelial cells, vascular smooth muscle cells, and synovial lining cells proliferate. In contrast, despite marked alteration in the extracellular matrix (ECM) component of the tenosynovium, the fibroblasts responsible for most ECM framework production do not proliferate during any phase of CTS. Histological analysis demonstrated that angiogenesis takes place only during the intermediate phase. Since clusters of capillaries and arterioles are often surrounded by type III collagen‐rich, disorganized, degenerate connective tissue, which contains fewer fibroblasts than normal, angiogenesis appears to take place as a part of a regenerative reaction that results in fibrosis. These findings strongly indicate that both PGE2 and VEGF are expressed in the tenosynovium in CTS during the intermediate phase and induce the histological changes seen in the tenosynovium. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Production and collision‐induced dissociation of gas‐phase, water‐ and alcohol‐coordinated uranyl complexes containing halide or perchlorate anions
Authors: Anbalagan Victor , Chien Winnie , Gresham Garold L. , Groenewold Gary S. , Van Stipdonk Michael J. 
Published: November 2004

AbstractElectrospray ionization was used to generate mono‐positive gas‐phase complexes of the general formula [UO2A(S)n]+ where A = OH, Cl, Br, I or ClO4, S = H2O, CH3OH or CH3CH2OH, and n = 1–3. The multiple‐stage dissociation pathways of the complexes were then studied using ion‐trap mass spectrometry. For H2O‐coordinated cations, the dissociation reactions observed included the elimination of H2O ligands and the loss of HA (where A = Cl, Br or I). Only for the Br and ClO4 versions did collision‐induced dissociation (CID) of the hydrated species generate the bare, uranyl–anion complexes. CID of the chloride and iodide versions led instead to the production of uranyl hydroxide and hydrated UO. Replacement of H2O ligands by alcohol increased the tendency to eliminate HA, consistent with the higher intrinsic acidity of the alcohols compared to water and potentially stronger UO2O interactions within the alkoxide complexes compared to the hydroxide version. Copyright © 2004 John Wiley & Sons, Ltd.
Minimal residual disease in melanoma
Authors: Max Nicole , Keilholz Ulrich 
Published: November 2004

AbstractA number of specific genes encoding for melanosomal proteins are selectively expressed in melanocytes and melanomas. For detection of circulating melanoma cells, the expression of the tyrosinase gene is most widely used. Several cohorts of melanoma patients from single institutions have been analyzed by various research groups for the presence of circulating melanoma cells in all stages of disease. The percentage of patients with evidence of occult tumor dissemination has been correlated with stage of disease in several, but not all, reports. Two prospective analyses suggest that the PCR result is of prognostic value in melanoma. Several laboratories have found PCR evidence for circulating melanoma cells in the vast majority of untreated patients with stage IV disease, although other groups have reported much lower frequencies. Taken together, there is a wide range of results. Methodological differences likely account for this discrepancy. With the availability of true quantitative RT‐PCR systems, such as the Light Cycler system, accurate quantification of tyrosinase transcripts over a range of 1–10,000 tumor cells per ml of blood is possible. Quantitative RT‐PCR systems also dramatically improve quality control, since exact quantitation of housekeeping gene mRNA facilitates determination of sample quality. Semin. Surg. Oncol. 20:319–328, 2001. © 2001 Wiley‐Liss, Inc.
Mature but not fetal or neonatal rat superior cervical ganglion transplants survive in the cortex of adult rats
Authors: Tuba Andrea , Kálmán Mihály , Senatorov Vladimir V. , Fülöp Zoltán 
Published: November 2004

AbstractThe transplantation of catecholaminergic tissues is a possible therapy for parkinsonism. Central nervous tissue is suitable for transplantation only in the immature stage, whereas peripheral nervous tissue can also be transplanted when mature. The present study compares the development of fetal (17–20 embryonic day, E17–20), neonatal (1–3 postnatal day, P1–3 and mature (5–6‐week‐old) rat superior cervical ganglia after transplantation into the cerebral cortex of adult rats. The mature transplants survived in greater proportion and preserved their structural characteristics, although a considerable proportion of the neurons died. The perinatal transplants only survived sporadically, decreased in size and the surviving remnants failed to display a structure comparable to the adult ganglion in situ. Thus, the use of adult donors is not only a possibility but a necessity when superior cervical ganglion (probably any ganglion) is transplanted. This principle is radically different from that seen in the case of central nervous tissues, and can be understood by the analysis of the time curves of cell proliferation and programmed cell death (apoptosis) observed during the perinatal development of sympathetic ganglia.
Types and activities of voltage‐operated calcium channels change during development of rat pituitary neurointermediate lobe
Authors: Beatty Diane M. , Sands Scott A. , Morris Stephen J. , Chronwall Bibie M. 
Published: November 2004

AbstractCultures of pituitary neurointermediate lobe cells were established from rats aged 1, 12, and 42 days to identify the types and assess the activities of Ca2+ channels present in melanotropes, glial‐like cells, and fibroblasts during development. Day 12 represents the time at which dopaminergic axons have become distributed throughout the lobe, glial cells begin to lose their radial orientation, and melanotropes robustly express the short isoform of the dopamine D2 receptor. Thus, we studied Ca2+ channels in relation to the event of innervation of melanotropes. Real‐time fluorescence video microscopy, in the presence of pharmacological agents, which block L‐, N‐, P‐, and T‐type channels, was used as an indirect measurement of channel activity. Assessment of cell type was verified by triple‐label fluorescence immunohistochemistry. In melanotropes, extracellular Ca2+ addition caused Ca2+ influx through ω‐conotoxin GVIA‐sensitive, N‐type channels on days 1 and 12 but not on day 42. The K+ depolarization induced an increase in intracellular Ca2+ concentration in all age‐groups. This effect was decreased by nifedipinc, an L‐type channel blocker, at all ages, and by ω‐agatoxin IVa, a P‐type blocker, only on day 42. These results demonstrate that the predominance of N‐ or P‐type channels on melanotropes is age‐dependent and can be correlated with other developmental changes. The T‐type blocker, NiSO4, had no effect. In glial‐like cells of all ages, extracellular Ca2+ addition resulted in an increase in intracellular Ca2+ concentration, which was inhibited only by NiSO4. The percentage of responsive glial‐like cells was equally high in days 1 and 12 cultures, then declined by day 42. The K+ depolarization had no effect on glial‐like cells. Fibroblasts did not respond significantly to extracellular Ca2+ or K+ depolarization, indicating little detectable activity by this methodology from functional voltage‐operated Ca2+ channels.
Dietary goitrogen‐induced changes in the transport of 2‐deoxy‐d‐glucose and amino acids across the rat blood‐brain barrier
Authors: Bala T.S.S. , Janardanasarma M.K. , Raghunath M. 
Published: November 2004

AbstractThe hypothesis that a defect in the rate‐limiting blood‐brain barrier (BBB) nutrient transport may be one of the factors responsible for the brain defects seen in some iodine deficiency disorders was tested in Wistar/NIN rats fed potassium thiocyanate (KSCN), a synthetic goitrogen. The BBB nutrient transport was measured by the brain uptake index (BUI) method. Feeding KSCN to female rats (from weaning) through their growth, pregnancy and lactation (G1) but not from conception (G2) or parturition (G3) resulted in a significant decrease (≈23%) in the BBB transport of 2‐deoxy‐d‐glucose (2‐DG) in their offspring at weaning, compared with controls (C). Post‐weaning KSCN‐feeding (G4) of control pups did not affect their BBB 2‐DG transport (BUI: 36.2±4.98, vs 38.8±4.11). The effects of different KSCN regimens on BBB transport of leucine (leu), tyrosine (tyr) and sucrose (background marker) were inconsistent, of smaller magnitude (≈10%) and appeared to be of little significance. Withdrawing KSCN from the diet of chronically KSCN‐fed (G1) mothers from conception (G5) or parturition (G6) prevented the impairment of BBB 2‐DG transport in pups (BUI: 27.0±4.98, 20.8±3.27, 26.9±3.99 and 28.3±3.47 in C, G1, G5 and G6 pups, respectively); this was reversed by feeding the control diet to G1 pups from weaning. Withdrawal of dietary KSCN did not affect BBB transport of leu, tyr and sucrose. The decreased BBB transport of 2‐DG in G1 pups appears to be due to a decrease in affinity (Kt app 5.46 vs 4.15 mM) rather than in the capacity (Tmax app 0.94 vs 0.91 μmoles/g/min) of the transport system. Intracarotid injections of KSCN per se had no effect on BBB 2‐DG transport, suggesting that the effects may be secondary to the altered thyroid status of the animal.
Aerodynamic forces of revolving hummingbird wings and wing models
Authors: Altshuler Douglas L. , Dudley Robert , Ellington Charles P. 
Published: November 2004

AbstractA central challenge to the study of animal aerodynamics has been the measurement of forces generated by flapping wings. Relative to wings of other birds, hummingbird wings are of particular interest in that the smaller species operate in more viscous regimes (5000 < Re < 10 000) for which substantial drag and reduced lift:drag coefficients might be expected. Lift and drag forces were measured on mounted hummingbird wings and wing models spinning in continuous tipwise revolution about the wing base. Lift coefficients tended to increase as wing models became more realistic (i.e. with sharpened leading edges and with substantial camber). Lift:drag ratios of real wings were substantially higher than those of wing models, suggesting morphological contributions of feathers to lift enhancement and drag reduction. At Re= 5000, high values of the lift:drag ratio (8–16) at low angles of attack suggest that wings of hummingbirds are exceptionally good at producing lift.
Satellite‐linked dive recorders provide insights into the reproductive strategies of crabeater seals (Lobodon carcinophagus)
Authors: Southwell Colin 
Published: November 2004

AbstractInsights into the reproductive strategies of crabeater seals Lobodon carcinophagus were obtained from satellite‐linked dive recorders deployed during the breeding season. All of the three females and seven males on which instruments were deployed hauled out continuously for extended periods of up to 24 days. The duration of extended haulout is consistent with a lactation period of around 3 weeks. In two cases where dive recorders were deployed on a male and female in the same group, the two animals stayed together on the ice continuously and entered the water at exactly the same time when extended haulout ceased. In both cases the male and female became geographically separated within a short time after entering the water, indicating that the association did not last beyond the period on the ice. Some males had multiple periods of extended haulout, suggesting they may try to find more than one female with which to mate. An optimal reproductive strategy with regard to the time spent on the ice may balance the conflicting needs of a short time imposed by the availability of breeding habitat and a long time to increase the reproductive success of males and females by finding more, or choosing between, mates.
Mutual amplification of apoptosis by statin‐induced mitochondrial stress and doxorubicin toxicity in human rhabdomyosarcoma cells
Authors: Werner Martin , Sacher Julia , Hohenegger Martin 
Published: November 2004

Besides their cholesterol‐lowering effect, 3‐hydroxy‐3‐methyl‐glutaryl‐CoA reductase inhibitors (statins) show antiproliferative behaviour, which has been suggested as a promising anticancer strategy. However, the signalling cascades leading to statin‐induced death of cancer cells are poorly characterized.
Here we show that statins activate the mitochondrial pathway of apoptosis in rhabdomyosarcoma RD cells via translocation of Bax from the cytosol to mitochondria. The prototypical representative of statins, simvastatin, induced consecutive activation of caspase 9 and 3 in a concentration‐dependent manner.
The permeability transition pore inhibitor bongkrekic acid was capable of completely preventing simvastatin‐induced caspase 9 and 3 activity, corroborating the mitochondrial pathway of apoptosis as the sole mechanism of statin action. Alternative pathways via death receptors, that is, caspase 8 or calpain activation, were not triggered by simvastatin.
Simvastatin‐treated RD cells could be completely rescued from apoptosis by the co‐application of mevalonic acid, indicating that deprivation of cholesterol precursors is essential for statin‐induced apoptosis.
However, pretreatment with subthreshold concentrations of simvastatin was sufficient to augment doxorubicin toxicity via the mitochondrial apoptotic machinery. Moreover, the presence of doxorubicin increased the potency of simvastatin to trigger caspase activation.
Taken together, these data highlight the therapeutic anticancer potential of statins and their additivity and mutual sensitization, in combination with doxorubicin in human rhabdomyosarcoma cells.

British Journal of Pharmacology (2004) 143, 715–724. doi:10.1038/sj.bjp.0705928
μ‐Opioid receptor desensitization: Is morphine different?
Authors: Connor Mark , Osborne Peregrine B , Christie MacDonald J 
Published: November 2004

Opioid tolerance and dependence are important phenomena. The contribution of acute μ‐opioid receptor regulatory mechanisms to the development of analgesic tolerance or physical dependence are unknown, and even the mechanisms underlying relatively rapid receptor desensitization in single cells are unresolved. To a large degree, the uncertainty surrounding the mechanisms and consequences of short‐term regulation of μ‐opioid receptors in single cells arises from the limitations in the experimental design in many of the studies that have investigated these events. Receptor overexpression and use of assays in which regulatory mechanisms are likely to blunt control determinations have led to measurements of opioid receptor activity that are likely to be insensitive to receptor uncoupling. Together with uncertainties concerning molecular details of μ‐opioid receptor interactions with potential regulatory molecules such as G protein‐coupled receptor kinases and arrestins, we are left with an incomplete picture crudely copied from the well‐worked‐out regulatory schema for β2‐adrenoceptors. As a consequence, suggestions that clinically relevant μ‐opioid receptor agonists may have different propensities to produce tolerance and dependence that arise from their differential recruitment of regulatory mechanisms are premature, and have not yet been appropriately assessed, nor explained in the context of a thoroughly established regulatory scheme. In this commentary, we outline the experimental limitations that have given rise to conflicting ideas about how μ‐opioid receptors are regulated, and identify the issues we feel still need to be addressed before we can understand why morphine promotes receptor trafficking differently to other opioids.British Journal of Pharmacology (2004) 143, 685–696. doi:10.1038/sj.bjp.0705938
ἕθνος and γνος in Herodotus
Authors: Jones C. P. 
Published: November 2004

Herodotus has often been considered the Father of Ethnography no less than the Father of History. It comes as a paradox, then, that he has been taxed with confusion in his use of two terms that recur over and over in his discussion of peoples, ἕθνος and γνος. Here is the formulation of Raymond Weil:Hérodote definit mal l‘ethnos’. C'est pour lui tantôot une subdivision du ‘génos’, tantôt au contraire un ensemble de ‘géné’. Ainsi 1' ‘ethnos’ des Médes, comme celui des Scythes, groupe plusieurs γνεα. Mais cet ‘ethnos’ scythe porte aussi le nom de ‘génos’, et comprend des ἕθνεα. Les Athéniens sont un ‘ethnos’ hellénique qui fait partie du ‘génos’ ionien, les Lacédémoniens un ‘ethnos’ pélasgique à rattacher au ‘génos’ dorien.