bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, resolution, and investigation of the rotational interconversion process of atropisomeric 1,n‐diaza[n]paracyclophanes using cyclodextrin‐mediated capillary zone electrophoresis
Authors: Scharwächter Klaus P. , Hochmuth Detlev H. , Dittmann Helmutt , König Wilfried A. 
Published: August 2002

AbstractA number of variously monosubstituted 1,n‐diaza[n]paracyclophanes (n = 10–12), which show planar chirality and atropisomerism due to hindered rotation about single bonds, were synthesized via a classical route to analyze their stereodynamic properties. Racemic analytes with 10‐ and 11‐membered bridges were resolved by capillary zone electrophoresis (CZE) in acidic phosphate buffers (pH 2.5–4.5) employing permethylated β‐ and γ‐cyclodextrin as chiral additives. Moreover, cyclodextrin mediated CZE was used in a discontinuously driven mode for investigations of the rotational interconversion process of conformationally labile homologues (n = 11). In stopped‐flow experiments, after baseline separation enantiomers were partially enantiomerized in situ inside the capillary by heating. The rate constants (kenan= ½krac) and rotational energy barriers (ΔG≠) were determined from the resulting enantiomeric ratios. Energy barriers between 113–126 kJ/mol were found depending on the substituent of the benzene ring and the degree of ionization of the amino groups in bridgehead positions. The energy barriers increased in order of the substituents: NO2>> CF3> Br > Cl > CH3≈ F. In addition, the rotational energy barriers were decreased by approximately 6–8 kJ/mol in the presence of the chiral selector. Chirality 13:679–690, 2001. © 2001 Wiley‐Liss, Inc.
Solvent‐dependent enantioselective interaction of some bis‐allylamide chiral selectors studied by NMR
Authors: Skogsberg Urban , Thunberg Linda , Allenmark Stig 
Published: August 2002

AbstractA series of chiral selectors, all of them bis‐allylamides of C2‐symmetric dicarboxylic acids, were studied by NMR in different solvents in an attempt to affect the equilibria between free selector and the diastereomeric complexes formed by its interaction with the (+)‐ and (−)‐forms of O,O′‐dibenzoyltartaric acid (DBTA). The results show that by changing the polarity of the solvent the equilibria are displaced, as observed from changing chemical shift differences. Phase‐sensitive 1H{1H}‐NOESY experiments revealed different interactions between the chiral selector and the analyte enantiomers. The individual equilibrium constants were determined by separate studies of the equilibria between the selector and the respective enantiomers of the chiral DBTA probe. Chirality 13:272–278, 2001. © 2001 Wiley‐Liss, Inc.
Resolution, configurational assignment, and enantiopharmacology at glutamate receptors of 2‐amino‐3‐(3‐carboxy‐5‐methyl‐4‐isoxazolyl)propionic acid (ACPA) and demethyl‐ACPA
Authors: Johansen Tommy N. , Stensbøl Tine B. , Nielsen Birgitte , Vogensen Stine B. , Frydenvang Karla , Sløk Frank A. , Brünum;uner‐Osborne Hans , Madsen Ulf , Krogsgaard‐Larsen Povl 
Published: August 2002

AbstractWe have previously described (RS)‐2‐amino‐3‐(3‐carboxy‐5‐methyl‐4‐isoxazolyl)propionic acid (ACPA) as a potent agonist at the (RS)‐2‐amino‐3‐(3‐hydroxy‐5‐methyl‐4‐isoxazolyl)propionic acid (AMPA) receptor subtype of (S)‐glutamic acid (Glu) receptors. We now report the chromatographic resolution of ACPA and (RS)‐2‐amino‐3‐(3‐carboxy‐4‐isoxazolyl)propionic acid (demethyl‐ACPA) using a Sumichiral OA‐5000 column. The configuration of the enantiomers of both compounds have been assigned based on X‐ray crystallographic analyses, supported by circular dichroism spectra and elution orders on chiral HPLC columns. Furthermore, the enantiopharmacology of ACPA and demethyl‐ACPA was investigated using radioligand binding and cortical wedge electrophysiological assay systems and cloned metabotropic Glu receptors. (S)‐ACPA showed high affinity in AMPA binding (IC50 = 0.025 μM), low affinity in kainic acid binding (IC50 = 3.6 μM), and potent AMPA receptor agonist activity on cortical neurons (EC50 = 0.25 μM), whereas (R)‐ACPA was essentially inactive. Like (S)‐ACPA, (S)‐demethyl‐ACPA displayed high AMPA receptor affinity (IC50 = 0.039 μM), but was found to be a relatively weak AMPA receptor agonist (EC50 = 12 μM). The stereoselectivity observed for demethyl‐ACPA was high when based on AMPA receptor affinity (eudismic ratio = 250), but low when based on electrophysiological activity (eudismic ratio = 10). (R)‐Demethyl‐ACPA also possessed a weak NMDA receptor antagonist activity (IC50 = 220 μM). Among the enantiomers tested, only (S)‐demethyl‐ACPA showed activity at metabotropic receptors, being a weak antagonist at the mGlu2 receptor subtype (KB = 148 μM). Chirality 13:523–532, 2001. © 2001 Wiley‐Liss, Inc.
Lack of desmin results in abortive muscle regeneration and modifications in synaptic structure
Authors: Agbulut Onnik , Li Zhenlin , Périé Sophie , Ludosky Marie‐Aline , Paulin Denise , Cartaud Jean , Butler‐Browne Gillian 
Published: August 2002

AbstractDesmin, a muscle‐specific intermediate filament protein, is expressed in all muscle tissues. Its absence leads to a multisystemic disorder involving cardiac, skeletal, and smooth muscles. In skeletal muscle, structural abnormalities include lack of alignment of myofibrils, Z disk streaming, and focal muscle degeneration. In this study, we have examined the consequences of an absence of desmin on the mechanisms of regeneration and the integrity of the neuromuscular junction. The muscles of desmin knock‐out and wild‐type mice were made to regenerate by injecting cardiotoxin and were examined 7 to 42 days following the injection. The absence of desmin resulted in a delayed and modified regeneration and an accumulation of adipocytes. This was associated with a persistence of small diameter muscle fibers containing both N‐CAM and developmental myosin isoforms. The amount of the slow myosin was increased, whereas there was a decrease in the fast isoform in the regenerated muscles of desmin knock‐out mice. Both regeneration and aging led to the appearance of elongated neuromuscular junctions with diffuse acetylcholinesterase staining and a decrease in the overall acetylcholinesterase activity in the muscles of these mice. The neuromuscular junctions were markedly disorganised and in some cases postjunctional folds were absent. We conclude that desmin is essential for terminal muscle regeneration, maturation of muscle fibers, and maintaining the complex folded structure of the postsynaptic apparatus of the neuromuscular junctions. Cell Motil. Cytoskeleton 49:51–66, 2001. © 2001 Wiley‐Liss, Inc.
Motional smearing of electrically recovered couplings measured from multipulse transients
Authors: Riley Scott A. , Vyas Shashi , Augustine Matthew P. 
Published: August 2002

AbstractThe measurement of residual dipolar and quadrupolar coupling constants in the liquid phase by using an electric field to destroy the isotropic nature of molecular tumbling is complicated by charge‐induced turbulent motion. In many cases this motion is due to charge injection at electrode surfaces, an effect that leads to an apparent removal of electrically recovered anisotropic spectral splittings when measured from a spin‐echo envelope modulation produced by a train of radio frequency (rf) pulses. To understand this averaging, the effect of quadrupolar couplings and enhanced molecular diffusion on free‐induction, spin‐echo, and Carr–Purcell signals is analytically determined in the special case of homogeneous rf pulses. Additional signal damping due to rf inhomogeneity and coupling constant heterogeneity is determined by numerically extending the kernel formalism introduced by Herzog and Hahn to understand spin diffusion in solids. Finally, the merit of the numerical approach is tested by comparison with analytical results for homogeneous rf pulses and experimental results for perdeuterated nitrobenzene involving inhomogeneous rf pulses and coupling heterogeneity. © 2001 John Wiley & Sons, Inc. Concepts Magn Reson 13: 171–189, 2001
Physical exercise and immune system function in cancer survivors
Authors: Fairey Adrian S. , Courneya Kerry S. , Field Catherine J. , Mackey John R. 
Published: August 2002

AbstractBACKGROUNDThere are a limited number of interventions for cancer survivors following completion of primary therapy that might reduce the risk of cancer recurrence and/or secondary malignancies and increase survival times. It has been proposed that physical exercise may be beneficial by enhancing the anticancer immune system response. The purpose of the current article is to: 1) briefly describe the immune system response to tumors, 2) discuss the impact of anticancer therapy on immune system function in cancer survivors, 3) provide a systematic and comprehensive review of the extant literature examining physical exercise and immune system function in cancer survivors, and 4) offer a critical analysis of this literature and outline directions for future research.METHODSA comprehensive literature search up to March 2001 identified empirical articles that examined the effects of physical exercise training on immune system function in cancer survivors from CD‐ROM database searches and manual searches.RESULTSTo the authors' knowledge, six empirical studies published between 1994 and 2000 have examined physical exercise and immune system function in cancer survivors. Overall, four out of six studies reported statistically significant improvements in a number of cancer‐related immune system components as a result of exercise. However, there are several limitations that must be considered when interpreting the findings of these studies. These limitations involve the samples, designs, physical exercise interventions, physical fitness assessments, and immunologic assessments.CONCLUSIONSAdditional research is needed to determine if physical exercise in cancer survivors may reduce the risk of cancer recurrence and secondary malignancies and increase survival times. Cancer 2002;94:539–51. © 2002 American Cancer Society.
A population‐based study of pediatric anaplastic large cell lymphoma
Authors: Alessandri Angela J. , Pritchard Sheila L. , Schultz Kirk R. , Massing Bonnie G. 
Published: August 2002

AbstractBACKGROUNDAnaplastic large cell lymphoma (ALCL) is a relatively rare form of non‐Hodgkin lymphoma (NHL) in children constituting 10–15% of this entity. To the authors' knowledge, there are no population‐based pediatric studies in the literature, and incidence estimates have not been attempted.METHODSA population‐based study of all children in British Columbia, Canada, younger than 15 years of age presenting between January 1988 and December 1999 with an immunohistologically confirmed diagnosis of CD30+ ALCL was completed. Demographic, ethnic, clinical, treatment, and outcome details were collected on all patients. Population figures were obtained from census data through the BC STATS.RESULTSTen patients were identified and confirmed to have ALCL on the basis of morphology and immunohistochemical stains. This equates to an annual incidence of 1.2 per million children younger than 15 years of age. The mean age at diagnosis was 8.23 years with a range of 1.4–13.0 years. There was an overrepresentation of East and Southeast Asian patients (40%) in the ALCL group compared with other subtypes of NHL and the pediatric population of British Columbia. Twenty percent of the patients had evidence of central nervous system (CNS) disease at diagnosis.CONCLUSIONSThe annual incidence of ALCL in children younger than 15 years of age in British Columbia is 1.2 per million. The overrepresentation of East and Southeast Asian ethnic origin remains unexplained. The rate of CNS involvement is much higher than that previously reported in large non‐population‐based series (0–3%). Although the low numbers do not allow firm conclusions, it would seem prudent to continue to investigate all newly diagnosed patients for CNS involvement in British Columbia. Cancer 2002;94:1830–5. © 2002 American Cancer Society.DOI 10.1002/cncr.10396
Early development of the retina and pineal complex in the sea lamprey: Comparative immunocytochemical study
Authors: Meléndez‐Ferro Miguel , Villar‐Cheda Begoña , Manoel Abalo Xesús , Pérez‐Costas Emma , Rodríguez‐Muñoz Rolando , Degrip Willem J. , Yáñez Julián , Rodicio María Celina , Anadón Ramón 
Published: August 2002

AbstractLampreys have a complex life cycle, with largely differentiated larval and adult periods. Despite the considerable interest of lampreys for understanding vertebrate evolution, knowledge of the early development of their eye and pineal complex is very scarce. Here, the early immunocytochemical organization of the pineal complex and retina of the sea lamprey was studied by use of antibodies against proliferating cell nuclear antigen (PCNA), opsin, serotonin, and γ‐aminobutyric acid (GABA). Cell differentiation in the retina, pineal organ, and habenula begins in prolarvae, as shown by the appearance of PCNA‐negative cells, whereas differentiation of the parapineal vesicle was delayed until the larval period. In medium‐sized to large larvae, PCNA‐immunoreactive (‐ir) cells were numerous in regions of the lateral retina near the differentiated part of the larval retina (central retina). A late‐proliferating region was observed in the right habenula. Opsin immunoreactivity appears in the pineal vesicle of early prolarvae and 3 or 4 days later in the retina. In the parapineal organ, opsin immunoreactivity was observed only in large larvae. In the pineal organ, serotonin immunoreactivity was first observed in late prolarvae in photoreceptive (photoneuroendocrine) cells, whereas only a few of these cells appeared in the parapineal organ of large larvae. No serotonin immunoreactivity was observed in the larval retina. GABA immunoreactivity appeared earlier in the retina than in the pineal complex. No GABA‐ir perikaryon was observed in the retina of larval lampreys, although a few GABA‐ir centrifugal fibers innervate the inner retina in late prolarvae. First GABA‐ir ganglion cells occur in the pineal organ of 15–17 mm larvae, and their number increases during the larval period. The only GABA‐ir structures observed in the parapineal ganglion of larvae were afferent fibers, which appeared rather late in development. The time sequence of development in these photoreceptive structures is rather different from that observed in teleosts and other vertebrates. This suggests that the unusual development of the three photoreceptive organs in lampreys reflects specialization for their different functions during the larval and adult periods. J. Comp. Neurol. 442:250–265, 2002. © 2001 Wiley‐Liss, Inc.
Intact sorting, targeting, and clustering of γ‐aminobutyric acid A receptor subtypes in hippocampal neurons in vitro
Authors: Brünig Ina , Scotti Eleonora , Sidler Corinne , Fritschy Jean‐Marc 
Published: August 2002

AbstractThe cellular and subcellular distribution of four GABAA receptor subtypes, identified by the presence of the α1, α2, α3, or α5 subunit, was investigated immunocytochemically in dissociated cultures of hippocampal neurons. We addressed the questions whether (1) cell‐type specific expression, (2) axonal/somatodendritic targeting, and (3) synaptic/extrasynaptic clustering of GABAA receptor subtypes was retained in vitro. For comparison, the in vivo distribution pattern was assessed in sections from adult rat brain. The differential expression of GABAA receptor subunits allowed to identify five morphologically distinct cell types in culture: the α1 subunit was observed in glutamic acid decarboxylase–positive interneurons, the α2 and α5 subunits marked pyramidal‐like cells, and the α3 subunit labeled three additional cell types, including presumptive hilar cells. All subunits were found in the somatodendritic compartment. In addition, appropriate axonal targeting was evidenced by the intense α2, and sometimes α3 subunit labeling of axon‐initial segments (AIS) of pyramidal cells and hilar cells, respectively. Accordingly, both receptor subtypes were targeted to AIS in vivo, as well. Synaptic receptors were identified by colocalization with gephyrin, a postsynaptic clustering protein, and apposition to presynaptic terminals labeled with synapsin I. In vitro and in vivo, α1‐ and α2‐receptor subtypes formed numerous synaptic clusters, α3‐GABAA receptors were located either synaptically or extrasynaptically depending on the cell type, whereas α5‐GABAA receptors were extrasynaptic. We conclude that receptor targeting to broad subcellular locations does not require specific GABAergic innervation patterns, which are disturbed in vitro, but depends on protein‐protein interactions in the postsynaptic cell that are both subunit‐ and neuron‐specific. J. Comp. Neurol. 443:43–55, 2002. © 2002 Wiley‐Liss, Inc.
Localization of P2X3 receptors and coexpression with P2X2 receptors during rat embryonic neurogenesis
Authors: Cheung Kwok‐Kuen , Burnstock Geoffrey 
Published: August 2002

AbstractIt is well known that extracellular ATP mediates rapid excitatory signaling by means of the ionotropic P2X receptors. One of its subunits, the P2X3 receptor, is well documented to be associated with sensory innervation in adult animals. It is speculated that the P2X3 receptor may have already been present in the early sensory system. The aim of this study was to investigate the distribution of the P2X3 receptor during neurogenesis by using immunohistochemistry on rat embryos from embryonic day (E)9.5–18.5. The P2X3 receptor was first identified in the hindbrain neural tube and the sensory ganglia in E11–11.5 embryos. At E14.5, the optic tract and retina, nucleus tractus solitarius, mesencephalic trigeminal nucleus, and sensory nerves in both respiratory and digestive tract showed positive staining. The facial nucleus, the prepositus hypoglossal nucleus, and the sympathetic ganglia also showed P2X3 immunoreactivity, even though these are not sensory associated. P2X3 immunoreactivity was detected in the vestibular nucleus, the nerves in mesentery, bladder, and kidney in E16.5 and in nerves in vibrissae in E18.5. P2X3 immunoreactivity in the facial nucleus, spinal trigeminal tract, the mesencephalic trigeminal nucleus, and the vestibular nucleus were undetectable in postnatal day 16 rat brainstem. The P2X3 receptor was coexpressed with the P2X2 receptor in nucleus tractus solitarius, dorsal root ganglion, nodose ganglion, and the taste bud in E16.5 embryo, which was 5 days later than the first appearance of the native P2X3 receptor. In summary, we present a detailed expression pattern of the P2X3 receptor during neurogenesis and report that P2X3 immunoreactivity is down‐regulated in early postnatal brainstems. J. Comp. Neurol. 443:368–382, 2002. © 2002 Wiley‐Liss, Inc.
Projections of the posterodorsal preoptic nucleus and the lateral part of the posterodorsal medial amygdala in male gerbils, with emphasis on cells activated with ejaculation
Authors: Simmons Danielle A. , Yahr Pauline 
Published: August 2002

AbstractThe posterodorsal preoptic nucleus (PdPN) and the lateral part of the posterodorsal medial amygdala (MeApd) express Fos with ejaculation in male gerbils. Ejaculation‐activated cells participate in the PdPN and MeApd projections to each other and to the sexually dimorphic preoptic area (SDA), but those projections involve less than 20% of the activated PdPN cells and less than 50% of the activated MeApd cells. To identify other potential targets of ejaculation‐activated cells, we traced PdPN and lateral MeApd outputs using biotinylated dextran amine. The principal part of the bed nucleus of the stria terminalis (BSTpr) and the anteroventral periventricular nucleus (AVPv) were labeled from both sites and were injected with Fluoro‐Gold to determine whether PdPN and lateral MeApd cells that express Fos with ejaculation would be retrogradely labeled. Fluoro‐Gold was also applied to the dorsomedial hypothalamus (DMH) and retrorubral field (RRF) because such injections label PdPN cells in rats. The PdPN‐DMH projection is minimal in gerbils, involving few, if any, ejaculation‐related cells. Ejaculation‐activated PdPN cells project to the AVPv (43%), dorsal BSTpr (30%), and RRF (12%). Those in the lateral MeApd project to the dorsal BSTpr (43%) and AVPv (18%). When these percentages are combined with those for ejaculation‐activated cells involved in the PdPN and lateral MeApd projections to each other and to the medial SDA, the totals reach 100%. Thus, every PdPN and MeApd cell activated with ejaculation may participate in one of these projections. Similar projections may contribute to the similar behavioral effects of the PdPN and MeApd. J. Comp. Neurol. 444:75–94, 2002. © 2002 Wiley‐Liss, Inc.
Synaptic organization of the mushroom body calyx in Drosophila melanogaster
Authors: Yasuyama Kouji , Meinertzhagen Ian A. , Schürmann Friedrich‐Wilhelm 
Published: August 2002

AbstractThe calyx neuropil of the mushroom body in adult Drosophila melanogaster contains three major neuronal elements: extrinsic projection neurons, presumed cholinergic, immunoreactive to choline acetyltransferase (ChAT‐ir) and vesicular acetylcholine transporter (VAChT‐ir) antisera; presumed γ‐aminobutyric acid (GABA)ergic extrinsic neurons with GABA‐like immunoreactivity; and local intrinsic Kenyon cells. The projection neurons connecting the calyx with the antennal lobe via the antennocerebral tract are the only source of cholinergic elements in the calyces. Their terminals establish an array of large boutons 2–7 μm in diameter throughout all calycal subdivisions. The GABA‐ir extrinsic neurons, different in origin, form a network of fine fibers and boutons codistributed in all calycal regions with the cholinergic terminals and with tiny profiles, mainly Kenyon cell dendrites. We have investigated the synaptic circuits of these three neuron types using preembedding immuno‐electron microscopy. All ChAT/VAChT‐ir boutons form divergent synapses upon multitudinous surrounding Kenyon cell dendrites. GABA‐ir elements also regularly contribute divergent synaptic input onto these dendrites, as well as occasional inputs to boutons of projection neurons. The same synaptic microcircuits involving these three neuron types are repeatedly established in glomeruli in all calycal regions. Each glomerulus comprises a large cholinergic bouton at its core, encircled by tiny vesicle‐free Kenyon cell dendrites as well as by a number of GABAergic terminals. A single dendritic profile may thereby receive synaptic input from both cholinergic and GABAergic elements in close vicinity at presynaptic sites with T‐bars typical of fly synapses. ChAT‐ir boutons regularly have large extensions of the active zones. Thus, Kenyon cells may receive major excitatory input from cholinergic boutons and considerable postsynaptic inhibition from GABAergic terminals, as well as, more rarely, presynaptic inhibitory signaling. The calycal glomeruli of Drosophila are compared with the cerebellar glomeruli of vertebrates. The cholinergic boutons are the largest identified cholinergic synapses in the Drosophila brain and an eligible prospect for studying the genetic regulation of excitatory presynaptic function. J. Comp. Neurol. 445:211–226, 2002. © 2002 Wiley‐Liss, Inc.