bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of the Dictyostelium Arp2/3 complex in endocytosis, cytokinesis, and chemotaxis
Authors: Insall Robert , Müller‐Taubenberger Annette , Machesky Laura , Köhler Jana , Simmeth Evelyn , Atkinson Simon J. , Weber Igor , Gerisch Günther 
Published: August 2002

AbstractThe Arp2/3 complex is a ubiquitous and important regulator of the actin cytoskeleton. Here we identify this complex from Dictyostelium and investigate its dynamics in live cells. The predicted sequences of the subunits show a strong homology to the members of the mammalian complex, with the larger subunits generally better conserved than the smaller ones. In the highly motile cells of Dictyostelium, the Arp2/3 complex is rapidly re‐distributed to the cytoskeleton in response to external stimuli. Fusions of Arp3 and p41‐Arc with GFP reveal that in phagocytosis, macropinocytosis, and chemotaxis the complex is recruited within seconds to sites where actin polymerization is induced. In contrast, there is little or no localization to the cleavage furrow during cytokinesis. Rather the Arp2/3 complex is enriched in ruffles at the polar regions of mitotic cells, which suggests a role in actin polymerization in these ruffles. Cell Motil. Cytoskeleton 50:115–128, 2001. © 2001 Wiley‐Liss, Inc.
Enhanced diagonal peak suppression in three‐dimensional TROSY‐type 15N‐resolved 1HN1HN NOESY spectra
Authors: Meissner Axel , Sørensen Ole Winneche 
Published: August 2002

AbstractA new method for enhanced diagonal peak suppression in the three‐dimensional TROSY–NOESY experiment is presented. The main source of residual diagonal signals in the conventional technique is spin flips of the passive 15N spins during the 1H1H NOESY mixing period. The new pulse sequence does not suppress this pathway, but it generates peaks at the positions of the relaxation‐induced artifacts with opposite phase of the artifacts so that cancellation occurs. The new technique is demonstrated using an 15N‐labeled protein sample, Neural Cell Adhesion Molecule (NCAM) 213–308 in H2O at 500 MHz. © 2002 John Wiley & Sons, Inc. Concepts Magn Reson 14: 1–8, 2002
BirdcageBuilder: Design of specified‐geometry birdcage coils with desired current pattern and resonant frequency
Authors: Chin Chih‐Liang , Collins Christopher M. , Li Shizhe , Dardzinski Bernard J. , Smith Michael B. 
Published: August 2002

AbstractA simple method for birdcage coil design (high pass, low pass, and band pass) is presented. Rather than iteratively approaching the Larmor resonant frequency with known capacitances and calculated inductances, a more versatile approach to birdcage coil design is developed and validated, in which the necessary capacitances are calculated using a desired current pattern, a calculated inductance, and a predetermined resonant frequency. In order to expedite coil design for experienced and novice coil builders, a computer program (BirdcageBuilder) is also implemented based on this method. Experimental results show that the calculated capacitances and actual capacitances for several existing birdcage coils are in good agreement. © 2002 Wiley Periodicals, Inc. Concepts in Magnetic Resonance (Magn Reson Engineering) 15: 156–163, 2002
Residual dipolar couplings in protein NMR
Authors: Brunner Eike 
Published: August 2002

AbstractPartial molecular alignment leads to an incomplete averaging of anisotropic magnetic interactions such as the magnetic dipole–dipole interaction, the chemical shift anisotropy, or the electric quadrupole interaction. The resulting so‐called “residual” anisotropic magnetic interactions currently become increasingly important in biomolecular NMR spectroscopy. In particular, residual dipolar couplings turn out to be extremely useful novel parameters for protein structure determination. The basic principles of this new methodology are discussed in the present review and recent applications are demonstrated. Different alignment mechanisms leading to partial orientation of protein molecules in solution are considered in detail. The influence of magnetic and electric fields applied to isotropic protein solutions is discussed. Various magnetically orienting media which can be admixed to protein solutions are described and compared. Experiments for the measurement of residual dipolar couplings in proteins and advantageous strategies for the use of residual dipolar couplings in structure calculations are reviewed. © 2001 John Wiley & Sons, Inc. Concepts Magn Reson 13: 238–259, 2001
Serum squamous cell carcinoma antigen is a useful biologic marker in patients with inverted papillomas of the sinonasal tract
Authors: Yasumatsu Ryuji , Nakashima Torahiko , Kuratomi Yuichiro , Hirakawa Naoya , Azuma M.S. Kaoru , Tomita Kichinobu , Cataltepe Sule , Silverman Gary A. , Clayman Gary L. , Komiyama Sohtaro 
Published: August 2002

AbstractBACKGROUNDInverted papilloma (IP) is a frequent benign sinonasal tumor that is characterized histologically by squamous metaplasia, epithelial acanthosis, and hyperplasia of the nasal epithelium. Because of its high recurrence rate and malignant transformation potential, careful long‐term follow up is necessary.METHODSThe purpose of the current report was to study the expression of squamous cell carcinoma (SCC) antigen in sinonasal IPs and to evaluate the usefulness of SCC antigen as a biologic marker for the follow‐up of patients with sinonasal IP. The expression of SCCA1 in three sinonasal IP cases, three sinonasal SCC cases, and cases of normal nasal epithelium were examined by Western blot analysis, and the SCCA1 expression pattern in 31 IP specimens and 4 carcinoma in IP specimens were evaluated immunohistochemically. The serum levels of SCC antigen in 11 patients with sinonasal IP also were analyzed.RESULTSSCCA1 was overexpressed in all three sinonasal IP tissues compared with sinonasal SCC tissues or normal nasal epithelium. SCCA1 cytoplasmic immunoreactivity was detected in the suprabasal epidermal keratinocytes of all 31 sinonasal IP cases. In the four carcinoma in IP specimens, SCCA1 expression in the papillomatous lesion was more intense than in the cancerous lesion. The serum SCC antigen level was high in 10 of 11 patients with IP (91%) and significantly decreased after surgical resection of the tumors.CONCLUSIONSThe results of the current study indicate that SCCA1 frequently is overexpressed and may play a biologic role in the development of sinonasal IPs. Serum SCC antigen may be a useful biologic marker in patients with sinonasal IP. Cancer 2002;94:152–8. © 2002 American Cancer Society.
Phase II trial of irinotecan in combination with amifostine in patients with advanced colorectal carcinoma
Authors: Delioukina Maria L. , Prager Diane , Parson Mandy , Hecht J. Randolph , Rosen Peter , Rosen Lee S. 
Published: August 2002

AbstractBACKGROUNDIrinotecan is effective in patients with advanced colorectal carcinoma in both first‐line and salvage settings but its use can be limited by serious side effects. Amifostine has been shown to reduce the incidence of cisplatin‐induced cumulative renal toxicity in patients with advanced ovarian carcinoma and nonsmall cell lung carcinoma. In the current pilot Phase II trial, the authors examined the potential role of amifostine as a protective agent against irinotecan‐induced diarrhea and myelosuppression and evaluated an every‐2‐weeks regimen as an alternative schedule for the administration of irinotecan in patients with previously treated metastatic colorectal carcinoma.METHODSAll patients received amifostine, 740 mg/m2, followed by irinotecan, 250 mg/m2, every 2 weeks. A 6‐week cycle of chemotherapy (every 2 weeks for 3 treatments) was chosen to assess toxicity and response. The main objective of the current study was to evaluate the impact of amifostine on gastrointestinal and hematologic toxicity.RESULTSA total of 22 patients entered the current study. Six of these 22 patients (27%) had WHO Common Toxicity Criteria Grade 3 or 4 diarrhea, including 2 patients (9%) with Grade 4 diarrhea. Eight of 22 patients (36.3%) developed Grade 3 or 4 neutropenia (Grade 4 in 4 of the 22 patients [18%]). Dose reduction was required in 25% of the treatment cycles. Five of the 22 patients (23%) withdrew from the trial due to amifostine toxicity. Of the 15 patients who were evaluable for response, 4 patients (26.6%) had achieved a partial response and 9 (60%) had stable disease as their best response.CONCLUSIONSThe combination of irinotecan with amifostine in patients with previously treated metastatic colorectal carcinoma did not appear to reduce irinotecan toxicity. Amifostine did not appear to interfere with the cytotoxic effect of irinotecan. The results of the current study did demonstrate efficacy and safety of the every‐2‐weeks irinotecan schedule that was comparable to other established regimens and these results support its feasibility as a reasonable alternative in this disease setting. Cancer 2002;94:2174–9. © 2002 American Cancer Society.DOI 10.1002/cncr.10432
Spatiotemporal expression patterns of slit and robo genes in the rat brain
Authors: Marillat Valérie , Cases Oliver , Nguyenf‐Ba‐Charvet Kim Tuyen , Tessier‐Lavigne Marc , Sotelo Constantino , Chédotal Alain 
Published: August 2002

AbstractDiffusible chemorepellents play a major role in guiding developing axons toward their correct targets by preventing them from entering or steering them away from certain regions. Genetic studies in Drosophila revealed a repulsive guidance system that prevents inappropriate axons from crossing the central nervous system midline; this repulsive system is mediated by the secreted extracellular matrix protein Slit and its receptors Roundabout (Robo). Three distinct slit genes (slit1, slit2, and slit3) and three distinct robo genes (robo1, robo2, rig‐1) have been cloned in mammals. However, to date, only Robo1 and Robo2 have been shown to be receptors for Slits. In rodents, Slits have been shown to function as chemorepellents for several classes of axons and migrating neurons. In addition, Slit can also stimulate the formation of axonal branches by some sensory axons. To identify Slit‐responsive neurons and to help analyze Slit function, we have studied, by in situ hybridization, the expression pattern of slits and their receptors robo1 and robo2, in the rat central nervous system from embryonic stages to adult age. We found that their expression patterns are very dynamic: in most regions, slit and robo are expressed in a complementary pattern, and their expression is up‐regulated postnatally. Our study confirms the potential role of these molecules in axonal pathfinding and neuronal migration. However, the persistence of robo and slit expression suggests that the couple slit/robo may also have an important function in the adult brain. J. Comp. Neurol. 442:130–155, 2002. © 2002 Wiley‐Liss, Inc.
Guidance of dopaminergic neuritic growth by immature astrocytes in organotypic cultures of rat fetal ventral mesencephalon
Authors: Johansson Saga , Strömberg Ingrid 
Published: August 2002

AbstractAstrocytes, with their many functions in producing and controlling the environment in the brain, are of great interest when it comes to studying regeneration after injury and neurodegenerative diseases such as in grafting in Parkinson's disease. This study was performed to investigate astrocytic guidance of growth derived from dopaminergic neurons using organotypic cultures of rat fetal ventral mesencephalon. Primary cultures were studied at different time points starting from 3 days up to 28 days. Cultures were treated with either interleukin‐1β (IL‐1β), which has stimulating effects on astrocytic proliferation, or the astrocytic inhibitor cytosine arabinoside (Ara‐C). Tyrosine hydroxylase (TH)‐immunohistochemistry was used to visualize dopaminergic neurons, and antibodies against glial fibrillary acidic protein (GFAP) and S100β were used to label astrocytes. The results revealed that a robust TH‐positive nerve fiber production was seen already at 3 days in vitro. These neurites had disappeared by 5 days. This early nerve fiber outgrowth was not guided by direct interactions with glial cells. Later, at 7 days in vitro, a second wave of TH‐positive neuritic outgrowth was clearly observed. GFAP‐positive astrocytic processes guided these neurites. TH‐positive neurites arborized overlying S100β‐positive astrocytes in an area distal to the GFAP‐positive astrocytic processes. Treatment with IL‐1β resulted in an increased area of TH‐positive nerve fiber network. In cultures treated with Ara‐C, neither astrocytes nor outgrowth of dopaminergic neurites were observed. In conclusion, this study shows that astrocytes play a major role in long‐term dopaminergic outgrowth, both in axonal elongation and branching of neurites. The long‐term nerve fiber growth is preceded by an early transient outgrowth of dopamine neurites. J. Comp. Neurol. 443:237–249, 2002. © 2002 Wiley‐Liss, Inc.
Extracellular matrix glycoproteins inhibit neurite production by cultured neurons
Authors: De‐Miguel Francisco F. , Vargas Javier , Arias Clorinda , Escamilla Carolina 
Published: August 2002

AbstractWe have analyzed the role of extracellular matrix glycoproteins in the formation of a bipolar outgrowth pattern of identified leech neurons in culture. Adult anterior pagoda (AP) neurons cultured on the inner surface of the ganglion capsules that surround central nervous system, generate two processes oriented in opposite directions. This pattern differs from those produced by these neurons cultured on other substrates, and is similar to the pattern of developing AP neurons at embryonic day 10. We used different lectins to identify subsets of glycoproteins in the extracellular matrix (ECM) of the capsules and to study their contribution to the formation of the bipolar outgrowth pattern. ECM glycoproteins binding to peanut agglutinin (PNA) or Galanthus nivalis aglutinin (GNA) lectins were detected in ganglion capsules and in ganglion extracts that had been separated by electrophoresis and blotted to nitrocellulose membranes. Four protein bands bound to PNA lectin and six other bands, including laminin subunits, bound to GNA lectin. Other lectins failed to recognize any of the proteins. For AP neurons cultured on capsules, addition of PNA lectin to the culture medium produced a dose‐dependent increase in the number of primary neurites without affecting their shape, length or number of branch points. However, PNA lectin used as substrate did not affect sprouting of AP neurons. Our results suggest that PNA‐binding extracellular matrix glycoproteins regulate the formation of the bipolar pattern of AP neurons by inhibiting the formation of neurites. J. Comp. Neurol. 443:401–411, 2002. © 2002 Wiley‐Liss, Inc.
Colocalization of γ‐aminobutyric acid‐like immunoreactivity and catecholamines in the feeding network of Aplysia californica
Authors: Díaz‐Ríos Manuel , Oyola Eduardo , Miller Mark W. 
Published: August 2002

AbstractFunctional consequences of neurotransmitter coexistence and cotransmission can be readily studied in certain experimentally favorable invertebrate motor systems. In this study, whole‐mount histochemical methods were used to identify neurons in which γ‐aminobutyric acid (GABA)‐like immunoreactivity (GABAli) was colocalized with catecholamine histofluorescence (CAh; FaGlu method) and tyrosine hydroxylase (TH)‐like immunoreactivity (THli) in the feeding motor circuitry (buccal and cerebral ganglia) of the marine mollusc Aplysia californica. In agreement with previous reports, five neurons in the buccal ganglia were found to exhibit CAh. These included the paired B20 buccal‐cerebral interneurons (BCIs), the paired B65 buccal interneurons, and an unpaired cell with projections to both cerebral‐buccal connectives (CBCs). Experiments in which the FaGlu method was combined with the immunohistochemical detection of GABA revealed double labeling of all five of these neurons. An antibody generated against TH, the rate‐limiting enzyme in the biosynthesis of catecholamines, was used to obtain an independent determination of GABA‐CA colocalization. Biocytin backfills of the CBC performed in conjunction with TH immunohistochemistry revealed labeling of the rostral B20 cell pair and the unpaired CBI near the caudal surface of the right hemiganglion. THli was also present in a prominent bilateral pair of caudal neurons that were not stained with CBC backfills. On the basis of their position, size, shape, and lack of CBC projections, the lateral THli neurons were identified as B65. Double‐labeling immunohistochemical experiments revealed GABAli in all five buccal THli neurons. Finally, GABAli was observed in individual B20 and B65 neurons that were identified using electrophysiological criteria and injected with a marker (neurobiotin). Similar methods were used to demonstrate that a previously identified catecholaminergic cerebral‐buccal interneuron (CBI) designated CBI‐1 contained THli but did not contain GABAli. Although numerous THli and GABAli neurons and fibers were present in the cerebral and buccal ganglia, additional instances of their colocalization were not observed. These findings indicate that GABA and a catecholamine (probably dopamine) are colocalized in a limited number of interneurons within the central pattern generator circuits that control feeding‐related behaviors in Aplysia. J. Comp. Neurol. 445:29–46, 2002. © 2002 Wiley‐Liss, Inc.
Functional aspects of dopamine metabolism in the putative prefrontal cortex analogue and striatum of pigeons (Columba livia)
Authors: Bast Tobias , Diekamp Bettina , Thiel Christiane , Schwarting Rainer K.W. , Güntürkün Onur 
Published: August 2002

AbstractDopamine (DA) in mammalian associative structures, such as the prefrontal cortex (PFC), plays a prominent role in learning and memory processes, and its homeostasis differs from that of DA in the striatum, a sensorimotor region. The neostriatum caudolaterale (NCL) of birds resembles the mammalian PFC according to connectional, electrophysiological, and behavioral data. In the present study, DA regulation in the associative NCL and the striatal lobus parolfactorius (LPO) of pigeons was compared to uncover possible differences corresponding to those between mammalian PFC and striatum. Extracellular levels of DA and its metabolites (homovanillic acid [HVA], dihydroxyphenylacetic acid [DOPAC]) and the serotonin metabolite 5‐hydroxyindoleacetic acid (5‐HIAA) were investigated by in vivo microdialysis of urethane‐anesthetized pigeons under basal conditions and after systemic administration of D‐amphetamine. DA was reliably determined only in LPO dialysates, and DA metabolite levels were significantly higher in LPO than in NCL. The HVA/DOPAC ratio, indicating extracellular lifetime of DA, was more than twice as high in NCL than in LPO dialysates. After amphetamine, DA increased in LPO while still being undetectable in NCL, and DA metabolites decreased in both regions. 5‐HIAA slightly decreased in NCL dialysates. Amphetamine effects were delayed in NCL compared with the striatum. In conclusion, effects of amphetamine on the pigeon's ascending monoamine systems resemble those found in mammals, suggesting similar regulatory properties. The neurochemical differences between NCL and LPO parallel those between associative regions, such as PFC and dorsal striatum in mammals. They may reflect weaker regulation of extracellular DA, favoring DAergic volume transmission, in associative than striatal forebrain regions. J. Comp. Neurol. 446:58–67, 2002. © 2002 Wiley‐Liss, Inc.
Distribution and terminal arborizations of cutaneous mechanoreceptors in the glabrous finger pads of the monkey
Authors: Paré Michel , Smith Allan M. , Rice Frank L. 
Published: August 2002

AbstractRecent electrophysiological studies demonstrated that neurons in the somatosensory cortex of monkeys respond to tangential forces applied to glabrous skin. To unravel the peripheral basis for this cortical response, we determined the distribution of presumptive low‐threshold mechanoreceptors innervating the distal finger pads of monkeys. Endings were reconstructed in immunolabeled serial sections imaged by epifluorescence and confocal microscopy. Although classically implicated as cutaneous stretch receptors, no Ruffini corpuscles were found in the glabrous skin. Ruffini‐like endings were only detected at the base of the finger nails. Pacinian corpuscles were sparsely distributed in the deep dermis. Meissner corpuscles (MCs) in dermal papillary ridges had a comparably high density in the thumb, index, and fifth fingers. Each MC was innervated by several large‐caliber axons. Within the limits of our reconstructions, some of these axons terminated in only one MC, whereas others innervated several MCs. Merkel endings covered about 80% of the base of the intermediate epidermal ridges that form the pattern of fingerprints. In some cases, the distal tip of a Merkel‐related axon gave rise to a several terminal branches that supplied endings to tightly circumscribed (30–70 μm) clusters of Merkel cells. In other cases, the nodes of axons gave rise to en passant branches that formed extended chains of endings among Merkel cells spread over territories up to 300 μm long. Based on their relatively diffuse distributions, the axons that innervate multiple MCs or the axons with en passant Merkel terminations seem most suited to transduce tangential forces. J. Comp. Neurol. 445:347–359, 2002. © 2002 Wiley‐Liss, Inc.
Cellular basis for the effects of substance P in the periaqueductal gray and dorsal raphe nucleus
Authors: Commons Kathryn G. , Valentino Rita J. 
Published: August 2002

AbstractSubstance P (SP) is known to act at supraspinal sites to influence pain sensitivity as well as to promote anxiety. The effects of SP could be mediated in part by actions in the periaqueductal gray (PAG) and the dorsal raphe nucleus (DRN), adjoining mesencephalic cell groups that are strategically positioned to influence both nociception and mood. Previous studies have indicated that SP regulates both enkephalin and serotonin neurotransmission in these brain regions. To determine the mechanism underlying the effects of SP in the PAG and DRN, the distribution of the principal receptor for SP, the neurokinin 1 (NK1) receptor, was examined with respect to other neurotransmitter markers. PAG neurons that had NK1 receptor immunolabeling were interdigitated with and received contacts from enkephalin‐containing neurons. However, only a few (16/144; 11%) neurons with NK1 receptor also contained enkephalin immunoreactivity after colchicine treatment. In the DRN, dendrites containing NK1 receptor were selectively distributed in the dorsomedial subdivision. The majority (132/137; 96%) of these dendrites did not contain immunoreactivity for the serotonin‐synthesizing enzyme tryptophan hydroxylase. In contrast, neuronal profiles with NK1 receptor in both the PAG and the DRN often contained immunolabeling for glutamate. Light and electron microscopic examination revealed that 48–65% of cell bodies and dendrites with NK1 receptor were dually immunolabeled for glutamate. These data suggest that SP directly acts primarily on glutamatergic neurons in the PAG and DRN. To a lesser extent, enkephalin‐containing neurons may be targeted. Through these actions, it may subsequently influence activity of larger populations of neurons containing enkephalin as well as serotonin. This circuitry could contribute to, as well as coordinate, effects of SP on pain perception and mood. J. Comp. Neurol. 447:82–97, 2002. © 2002 Wiley‐Liss, Inc.