bluuebunny/crossref_metadata_2025 huggingface dataset:
Laminar distribution of synaptopodin in normal and reeler mouse brain depends on the position of spine‐bearing neurons
Authors: Deller Thomas , Haas Carola A. , Deissenrieder Kathrin , Del Turco Domenico , Coulin Carola , Gebhardt Carl , Drakew Alexander , Schwarz Karin , Mundel Peter , Frotscher Michael
Published: October 2002

Synaptopodin is the first member of a novel class of proline‐rich actin‐associated proteins. In brain, it is present in the neck of a subset of mature telencephalic spines and is associated closely with the spine apparatus, a Ca2+ storing organelle within the spine compartment. The characteristic region‐ and lamina‐specific distribution of synaptopodin in rat brain suggested that the distribution pattern of synaptopodin depends on the cytoarchitectonic arrangement of spine‐bearing neurons. To test this hypothesis, synaptopodin was studied in the cortex, striatum, and hippocampus of normal and reeler mice, in which developmental cell migration defects have disrupted the normal array of cells. In situ hybridization histochemistry as well as light‐ and electron microscopic immunocytochemistry were used. In brain of normal mice, the pattern of synaptopodin mRNA‐expressing cells corresponds to that of spine‐bearing neurons and synaptopodin protein is found in a region‐ and lamina‐specific distribution pattern. It is specifically sorted to the spine neck where it is associated closely with the spine apparatus. In brain of reeler mice, the pattern of synaptopodin mRNA‐expressing cells corresponds to that of the abnormally positioned spine‐bearing neurons and the region‐ and lamina‐specific distribution pattern is absent or altered. Nevertheless, synaptopodin was specifically sorted to the spine neck, as in controls. These data demonstrate that the light microscopic distribution pattern of synaptopodin protein depends on the position and orientation of the spine‐bearing neurons. The intracellular sorting process, however, is independent of positional cues. J. Comp. Neurol. 453:33–44, 2002. © 2002 Wiley‐Liss, Inc.
Direct projections from the cardiovascular nucleus tractus solitarii to pontine preganglionic parasympathetic neurons: A link to cerebrovascular regulation
Authors: Agassandian Khristofor , Fazan Valeria P.S. , Adanina Valentina , Talman William T.
Published: October 2002

Peripheral or central interruption of the baroreflex or the parasympathetic innervation of cerebral vessels leads to similar changes in regulation of cerebral blood flow. Therefore, we sought to test the hypothesis that the cardiovascular nucleus tractus solitarii, the site of termination of arterial baroreceptor nerves, projects to pontine preganglionic neurons whose stimulation elicits cerebral vasodilatation. The current study utilized both light and electron microscopic techniques to analyze anterograde tracing from the cardiovascular nucleus tractus solitarii to preganglionic parasympathetic neurons in the pons. We further used retrograde tracing from that same pontine region to the cardiovascular nucleus tractus solitarii and evaluated the confluence of tracing from the cardiovascular nucleus tractus solitarii to pontine preganglionic neurons labeled retrogradely from the pterygopalatine ganglia. The cardiovascular nucleus tractus solitarii projected to pontine preganglionic parasympathetic neurons, but more rostral and caudal regions of nucleus tractus solitarii did not. In contrast, all three regions of nucleus tractus solitarii projected to the nucleus ambiguus and dorsal motor nucleus of the vagus. Although not projecting to pontine preganglionic parasympathetic neurons, regions lateral, rostral, and caudal to cardiovascular nucleus tractus solitarii sent projections through the pons medial to the preganglionics. The study establishes the presence of a direct monosynaptic pathway from neurons in the cardiovascular nucleus tractus solitarii to pontine preganglionic parasympathetic neurons that project to the pterygopalatine ganglia, the source of nitroxidergic vasodilatory innervation of cerebral blood vessels. It provides evidence that activation of those preganglionic neurons can cause cerebral vasodilatation and increased cerebral blood flow. Finally, it demonstrates differential innervation of medullary and pontine preganglionic parasympathetic neurons by different regions of the nucleus tractus solitarii. J. Comp. Neurol. 452:242–254, 2002. © 2002 Wiley‐Liss, Inc.
Inhibitory amino acid transmitters associated with axons in presynaptic apposition to cutaneous primary afferent axons in the cat spinal cord
Authors: Sutherland Fiona I. , Bannatyne B. Anne , Kerr Robert , Riddell John S. , Maxwell David J.
Published: October 2002

The purpose of the present study was to characterize the transmitter content of structures in presynaptic apposition to the central terminals of cutaneous afferent fibers in the dorsal horn of the spinal cord. Axons in the Aαβ conduction velocity range were identified in adult cats, stained intra‐axonally with horseradish peroxidase, and prepared for combined light and electron microscopy. In total, we labeled two slowly adapting (Type 1) axons, two hair‐follicle afferents, and one rapidly adapting (Krause) afferent. Ninety‐nine labeled boutons were examined through complete series of serial sections. Approximately 80% of boutons originating from rapidly adapting and hair‐follicle afferents were postsynaptic to other axons, but only 50% of boutons from slowly adapting axons were associated with this type of arrangement. Postembedding immunogold reactions revealed that between 80% (for slowly adapting axons) and 100% (for rapidly adapting axons) of boutons presynaptic to primary afferents were immunoreactive for γ‐aminobutyric acid (GABA). The vast majority of these terminals (in excess of 80%) were also enriched with glycine. Therefore, presynaptic inhibition of these three functional classes of Aαβ cutaneous primary afferents is mediated principally by the subgroup of GABAergic interneuron that also contains glycine. J. Comp. Neurol. 452:154–162, 2002. © 2002 Wiley‐Liss, Inc.
Identical cellular distribution of all abundant neuropeptides in the major abdominal neurohemal system of an insect (Periplaneta Americana)
Authors: Eckert Manfred , Herbert Zsófia , Pollák Edit , Molnár László , Predel Reinhard
Published: October 2002

The median neurosecretory cells in abdominal ganglia of insects synthesize a number of putative hormones, which are abundant in the abdominal perisympathetic organs (PSOs). The peptide inventory of these prominent neurohemal release sites is best investigated in the American cockroach and strongly differs from that of head/thoracic neurohemal organs. In this study, we found a complete colocalization of all abundant neuropeptides in this hormonal system, including periviscerokinin‐1 and ‐2, pyrokinin‐5, YLSamide, VEAacid, and SKNacid. The first immunoreactive cells were detected on day 18 of embryonic development and already contained the complete set of peptides. By using antisera against the above‐mentioned peptides, the development of this neurohormonal system could be studied and is described in detail. Subsequent electron microscopic immunogold stainings in PSO preparations revealed the costorage of PSO peptides in a single vesicle species. Surprisingly, all these peptides were found in axons containing clear vesicles, whereas all axons with dense core vesicles were totally devoid of immunoreactivity. Unlike the axons with dense core vesicles, immunostained axons ramify in the center of the PSO but exhibit only rare morphological signs of exocytosis. Instead, putative release sites of the clear vesicle‐containing axons were detected peripherally to the PSOs, namely, on the hyperneural muscle. J. Comp. Neurol. 452:264–275, 2002. © 2002 Wiley‐Liss, Inc.
Systemic administration of interleukin‐1β activates select populations of central amygdala afferents
Authors: Buller Kathryn M. , Day Trevor A.
Published: October 2002

The central nucleus of the amygdala (CeA) is activated robustly by an immune challenge such as the systemic administration of the proinflammatory cytokine interleukin‐1β (IL‐1β). Because IL‐1β is not believed to cross the blood‐brain barrier in any significant amount, it is likely that IL‐1β elicits CeA cell recruitment by means of activation of afferents to the CeA. However, although many studies have investigated the origins of afferent inputs to the CeA, we do not know which of these also respond to IL‐1β. Therefore, to identify candidate neurons responsible for the recruitment of CeA cells by an immune challenge, we iontophoretically deposited a retrograde tracer, cholera toxin b‐subunit (CTb), into the CeA of rats 7 days before systemic delivery of IL‐1β (1 μg/kg, i.a.). By using combined immunohistochemistry, we then quantified the number of Fos‐positive CTb cells in six major regions known to innervate the CeA. These included the medial prefrontal cortex, paraventricular thalamus (PVT), ventral tegmental area, parabrachial nucleus (PB), nucleus tractus solitarius, and ventrolateral medulla. Our results show that after deposit of CTb into the CeA, the majority of double‐labeled cells were located in the PB and the PVT, suggesting that CeA cell activation by systemic IL‐1β is likely to arise predominantly from cell bodies located in these regions. These findings may have significant implications in determining the central pathways involved in generating acute central responses to a systemic immune challenge. J. Comp. Neurol. 452:288–296, 2002. © 2002 Wiley‐Liss, Inc.
Development of visual projections follows an avian/mammalian‐like sequence in the lizard Ctenophorus ornatus
Authors: Dunlop Sarah A. , Tee Lisa B.G. , Rodger Jenny , Harvey Alan R. , Roberts J. Dale , Beazley Lynda D.
Published: October 2002

Development of primary visual projections was examined in a lizard Ctenophorus ornatus by anterograde and retrograde tracing with DiI and by GAP‐43 immunohistochemistry. Visual pathway development was essentially similar to that in birds and mammals and thus differed from patterns in fish or amphibians. A number of features characterised the development as mammalian‐like. Three phases occurred in rapid succession after laying: outgrowth (2–3 weeks, early), exuberance (4–5 weeks, intermediate), and retraction to the adult pattern (6–8 weeks, late) at about the time of hatching and eye opening. Furthermore, ipsilateral projections developed with only a slight lag relative to the contralateral ones. The dorsally located fovea could be identified from early stages. Optic axons formed transient exuberant projections to the ipsilateral optic tectum, to the opposite optic nerve, and to nonvisual regions. The pattern resembled that formed in the long term by regenerating optic axons in C. ornatus (Dunlop et al. [2000b] J. Comp. Neurol. 416:188–200), suggesting that axons recognise molecular signals associated with the initial exuberant innervation but not those associated with subsequent refinement. J. Comp. Neurol. 453:71–84, 2002. © 2002 Wiley‐Liss, Inc.
Dynamically adapting to system load and program behavior in multiprogrammed multiprocessor systems
Authors: Kazi Iffat H. , Lilja David J.
Published: October 2002

Parallel execution of application programs on a multiprocessor system may lead to performance degradation if the workload of a parallel region is not large enough to amortize the overheads associated with the parallel execution. Furthermore, if too many processes are running on the system in a multiprogrammed environment, the performance of the parallel application may degrade due to resource contention. This work proposes a comprehensive dynamic processor allocation scheme that takes both program behavior and system load into consideration when dynamically allocating processors. This mechanism was implemented on the Solaris operating system to dynamically control the execution of parallel C and Java application programs. Performance results show the effectiveness of this scheme in dynamically adapting to the current execution environment and program behavior, and that it outperforms a conventional time‐shared system. Copyright © 2002 John Wiley & Sons, Ltd.
CD2 is expressed by a subpopulation of normal B cells and is frequently present in mature B‐cell neoplasms
Authors: Kingma Douglas W. , Imus Paula , Xie Xiu Y. , Jasper Gregory , Sorbara Lynn , Stewart Carleton , Stetler‐Stevenson Maryalice
Published: October 2002

Background

CD2 is expressed by T and natural killer (NK) cells and has been reported in T/NK cell lineage neoplasms as well as in immature B‐lymphoblastic and myeloid leukemias. Although CD2+ B‐cells have been identified in normal fetal and postnatal thymus, they have not been reported in adults.

Methods

We retrospectively reviewed flow cytometric immunophenotypic data on consecutive low‐grade B‐cell leukemias and lymphomas to investigate the frequency of CD2 expression. We also reviewed samples from normal healthy donors to determine whether there is a normal CD2+ B‐cell population.

Results

CD2 expression (partial or complete) was observed in 13 of 83 (16%) chronic lymphocytic leukemias (CLL), 16 of 29 (55%) follicle center lymphomas (FCL), 3 of 12 (25%) hairy cell leukemias (HCL), 0 of 6 mantle cell lymphomas (MCL), 8 of 28 (29%) large cell lymphomas (LCL), and in 0 of 5 marginal zone/mucosa‐associated lymphoid tissue lymphomas (MZL/MALT). We determined that 5.74 ± 2.46% (mean ± SD) of normal peripheral blood B cells and 6.48 ± 1.62 % (mean ± SD) of normal bone marrow B cells coexpress CD2.

Conclusions

CD2 expression in B‐cell neoplasia is a more prevalent phenomenon than previously appreciated. Normal CD2+ B‐cell populations are observed in adults and may represent the nonmalignant counterpart of CD2+ B‐cell neoplasms. Cytometry (Clin. Cytometry) 50:243–248, 2002. Published 2002 Wiley‐Liss, Inc.
Primary squamous‐cell carcinoma of the thyroid gland: New evidence in support of follicular epithelial cell origin
Authors: Sahoo Maheswar , Bal C.S. , Bhatnagar Dinesh
Published: October 2002

Primary squamous‐cell carcinoma (SCC) of the thyroid gland is extremely rare. We had an opportunity to treat two such cases recently. Two elderly females presented with left lobe thyroid swelling that had a history of long‐standing goiter. Fine‐needle aspiration (FNA) of the thyroid nodule was done in both cases. FNA cytology showed an thyroid abscess in the first, and a Hürthle‐cell neoplasm in the second case. Histopathologic diagnosis was a well‐differentiated squamous‐cell carcinoma with an adjacent area of lymphocytic thyroiditis in the first case, and a moderately differentiated squamous‐cell carcinoma in association with a Hürthle‐cell adenoma in the second case. Serial sections of the excised gland ruled out any other associated thyroid malignancy. Immunostaining for pan‐cytokeratin, thyroglobulin, and calcitonin were performed. The tumor, comprising polygonal and spindle cells, showed positive staining for cytokeratin and thyroglobulin; however, calcitonin did not stain any structures. Exhaustive clinical, endoscopic, and radiological examinations, i.e., X‐ray of the chest, contrast‐enhanced computer tomography (CECT) of the neck and chest, and ENT checkup in both cases did not reveal any primary site of squamous‐cell carcinoma as the likely source of the metastases, or any contiguous spread from neighboring structures. Both patients had ipsilateral nodal metastases, and both succumbed to the disease within 6 mo of histological diagnosis. The interesting observation in both cases was thyroglobulin positivity, indicating a follicular epithelial cell origin of the SCC. Diagn. Cytopathol. 2002;27:227–231. © 2002 Wiley‐Liss, Inc.
Orally active and selective benzylidene ketal M2 muscarinic receptor antagonists for the treatment of Alzheimer's disease
Authors: Boyle Craig D. , Lachowicz Jean E.
Published: October 2002

Numerous studies have implicated the cholinergic system as a target for Alzheimer's disease (AD) therapy. The currently marketed drugs for treatment of AD are acetylcholinesterase inhibitors, which increase levels of the neurotransmitter acetylcholine (ACh) by blocking its metabolic degradation. However, this mechanism results in a non‐selective enhancement of cholinergic activity in peripheral organs as well as brain, which could lead to detrimental side effects. Cholinergic enhancement in brain can also be achieved by blocking presynaptic release‐regulating autoreceptors. M2 muscarinic receptor activation inhibits ACh release in brain regions that are critical for learning and memory processes. Thus, M2 antagonists may prove beneficial for relief of cognitive deficits in AD. In this review, early discoveries of M2 muscarinic antagonists based on dibenzodiazepinones, natural products, piperazines, and piperidines are described. More specifically, the development of a benzylidene ketal class of M2 muscarinic antagonists is reviewed. Characterization and optimization of these agents have led to the identification of compounds with high M2 receptor affinity and subtype selectivity. These M2 antagonists also facilitate ACh release and enhance cognition in preclinical experimental paradigms. While clinical efficacy of these compounds has not been evaluated, M2 antagonists represent a promising treatment for AD. Drug Dev. Res. 56:310–320, 2002. © 2002 Wiley‐Liss, Inc.
Review of drug development and therapeutic role of cholinesterase inhibitors in Alzheimer's disease
Authors: Sramek John J. , Zarotsky Victoria , Cutler Neal R.
Published: October 2002

Researchers have for some time appreciated the role of the neurotransmitter acetylcholine in Alzheimer's disease, and have realized the development of a number of acetylcholinesterase inhibitors. Bridging and dynabridging studies have played an important role in the development of these agents. Several acetylcholinesterase inhibitors have demonstrated tolerability and efficacy in a number of clinical trials. The most common adverse events associated with acetylcholinesterase inhibitors are cholinergic in nature, namely nausea and vomiting. The various properties of the three acetylcholinesterase inhibitors in clinical use today provide the clinician with the only meaningful treatment choices for Alzheimer's disease (AD) at the present time. Drug Dev. Res. 56:347–353, 2002. Copyright © 2002 John Wiley & Sons, Ltd.
Role of meta‐analysis of clinical trials for Alzheimer's disease
Authors: López Arrieta Jesús M.
Published: October 2002

Alzheimer's disease (AD) is a growing worldwide medical, social, and economic problem. In all countries, both prevalence and incidence of this disorder increase with age. The task of translating scientific clinical research into effective interventions for dementia has proved to be a difficult challenge. Data about the effects of therapeutic interventions come from several sources of evidence, ranging from studies with little potential for systematic bias and minimal random error, such as well‐designed randomized controlled trials, through controlled but nonrandomized cohort and case‐control studies, all the way to opinions based on laboratory evidence or theory. Although clinical trials are widespread in AD, there is increasing recognition that the results of studies do not necessarily apply to the type of patients that are seen by clinicians because of differences in patient characteristics, comorbidities, cotherapies, severity of disease, compliance, local circumstances, and patients preferences, which may differ sufficiently from those in the trial situation to attenuate or change the benefit‐to‐risk ratio. There are several methods to address those issues, like pragmatic trials and n‐of‐1 trials. When data from randomized clinical trials do not provide clear answers from sufficiently similar studies in the magnitude of effect sizes, lack of statistical significance, or identification of subgroups, systematic reviews and meta‐analysis may help to provide a better summary of the data. A major difference between a traditional review and a systematic is the systematic nature in which studies are chosen and appraised. Traditional reviews are written by experts in the field who use differing and often subjective criteria to decide what studies to include and what weight to give them, and hence the conclusions are often very diverse, depending on the reviewer. Publication and selection bias is a major concern of traditional reviews. Systematic reviews and meta‐analysis are being increasingly used in dementia, propelled by the Cochrane Dementia and Cognitive Improvement Group, to make decisions about treatment, management, and care and to guide future research. This narrative review describes the rationale for randomized clinical trials and systematic reviews in dementia, particularly AD. Drug Dev. Res. 56:401–411, 2002. © 2002 Wiley‐Liss, Inc.
Nonsteroidal antiinflammatory drugs as therapeutic agents for Alzheimer's disease
Authors: Golde Todd E. , Eriksen Jason L. , Weggen Sascha , Sagi Sarah A. , Koo Edward H.
Published: October 2002

One feature of the end‐stage pathology of Alzheimer's disease (AD) is the presence of numerous inflammatory markers associated with the amyloid β protein (Aβ) deposits in the brain. Experimental data strongly suggests that Aβ aggregates can incite an inflammatory response, but there are also data suggesting that inflammation can promote Aβ production and deposition. Thus, antiinflammatory drugs may have some role in AD therapy. This idea is supported by epidemiologic data, which shows that long‐term use of nonsteroidal antiinflammatory drugs (NSAIDs) confers protection from the development of AD. Significantly, oral salicylates have not been consistently shown to confer protection. Such studies have raised questions regarding the target or targets of NSAIDs that account for their apparent protection from AD. We have recently found that some NSAIDs have a novel mechanism of action, namely, selective lowering of the pathogenic Aβ42 peptide, that could contribute to their efficacy in AD. Further study will be needed to determine if the classic antiinflammatory properties of NSAIDs, the Aβ42‐lowering property, another known or unknown property, or a combination of these contributes to NSAIDs apparent ability to protect individuals from the development of AD. Drug Dev. Res. 56:415–420, 2002. © Wiley‐Liss, Inc.
Elevated glutathione as a therapeutic strategy in Alzheimer's disease
Authors: Butterfield D. Allan , Pocernich Chava B. , Drake Jennifer
Published: October 2002

Alzheimer's disease (AD) is characterized by progressive loss of memory and cognition. Our laboratory and many others have shown that the AD brain is under extensive oxidative stress. Numerous therapeutic approaches to AD therapy have been hypothesized. Among these are exogenous antioxidants. We suggest that the body's own endogenous antioxidant systems should be mobilized against the oxidative stress inherent in AD brain. One of the most versatile antioxidants in the brain is glutathione. Glutathione is capable of protecting the cell against reactive oxygen species, redox metal ions, and reactive lipid peroxidation products and other electrophiles associated with AD. There are many ways to increase glutathione levels, and one or more of these ways to increase glutathione in the brain may be a promising therapeutic strategy for AD. Drug Dev. Res. 56:428–437, 2002. © 2002 Wiley‐Liss, Inc.
Role of GSK‐3β in Alzheimer's disease pathology
Authors: Planel Emmanuel , Sun Xiaoyan , Takashima Akihiko
Published: October 2002

Glycogen synthase kinase 3β (GSK‐3β) is an important regulatory kinase involved in multiple processes such as metabolic control, embryonic development, cell death, and oncogenesis. It has been found to interact with many molecules associated with Alzheimer's disease (AD) such as the microtubule‐associated protein tau, presenilin 1, the amyloid‐β peptide, the amyloid precursor protein, and acetylcholine. Furthermore, GSK‐3β might be involved in brain aging and longevity. As GSK‐3β is associated with so many components of AD pathology, we review the current data on the role of this kinase in tau hyperphosphorylation, then look at its association with AD‐related molecules and pathways, and finally discuss its involvement in cell death and aging. We attempt to integrate all these data to arrive at the proposition that GSK‐3β is a pivotal molecule in the evolution of AD and that developing drugs directed at this kinase might prove to be beneficial in the treatment of this devastating disease. Drug Dev. Res. 56:491–510, 2002. © 2002 Wiley‐Liss, Inc.
Chimeric analysis of Notch2 function: A role for Notch2 in the development of the roof plate of the mouse brain
Authors: Kadokawa Yuzo , Marunouchi Tohru
Published: October 2002

Notch proteins are transmembrane receptors involved in cell‐fate determination throughout development. Targeted disruption of either the Notch1 or Notch2 gene in mice results in embryonic lethality around embryonic day (E) 10.5 with widespread cell death. Although Notch1‐deficient mice show disorganized somitogenesis, Notch2 mutants did not show definitive abnormalities in any tissue expressing high levels of the Notch2 gene, including the central nervous system. To study Notch2 function in development beyond the embryonic lethal stage, we performed chimeric analysis between Notch2 mutant and wild‐type mouse embryos. Chimeric embryos developed normally and homozygous Notch2 mutant‐specific cell death was not observed. Although chimeric embryos showed normal mosaicism until E9.5 in all tissues studied to date, Notch2 homozygous mutant cells failed to contribute to formation of the roof plate of the diencephalon and mesencephalon at later developmental stages, when Notch2 is normally expressed at high levels at there. Furthermore, Notch2 heterozygous mutant cells were also excluded from the roof plate of the chimera, however, Notch2 heterozygous mutant mice developed normally. We also showed that Wnt‐1 and Mash1 expression patterns at the roof plate were disorganized in Notch2 homozygous mutant embryos. These results indicate that Notch2 plays an important role in development of the roof plate of the diencephalon and mesencephalon, and suggest that cellular rearrangement is involved in this process. © 2002 Wiley‐Liss, Inc.
Notch1 and Jagged1 expression by the developing pulmonary vasculature
Authors: Taichman Darren B. , Loomes Kathleen M. , Schachtner Susan K. , Guttentag Susan , Vu Colynda , Williams Patrick , Oakey Rebecca J. , Baldwin H. Scott
Published: October 2002

The molecular mechanisms of pulmonary vascular development are poorly understood. Cell‐specific developmental pathways are influenced by cell–cell signaling. Notch signaling molecules are highly conserved receptors active in many cell‐fate determination systems. Recent observations of Notch molecules and a Notch ligand, Jagged1, suggest their importance in vascular morphogenesis, and particularly pulmonary vascular development. We performed a systematic evaluation of Notch1/Jagged1 gene and protein expression in the developing mouse lung from embryonic day 11 until adulthood by using quantitative PCR, immunofluorescence, and electron microscopic analysis. mRNA transcripts for Notch1‐4 and Jagged1 increased progressively from early to later lung development, accompanied by a simultaneous rise in endothelial cell‐specific gene expression, a pattern not seen in other organs. Notch1 mRNA was identified on both epithelial and mesenchymal structures of the embryonic lung. Immunofluorescence staining revealed the progressive acquisition of Notch1 and Jagged1 proteins by the emerging endothelium. Notch1 and Jagged1 were seen initially on well‐formed, larger vessels within the embryonic lung bud and progressively on finer vascular networks. Each was also expressed on surrounding nonvascular structures. The localization of Notch1 and Jagged1 on endothelial cell surface membranes within the alveolar microvasculature was confirmed by immuno‐electron microscopy. These temporal and spatial patterns in Notch1/Jagged1 gene and protein expression suggest multiple potential paths of cell–cell signaling during lung development and vascular morphogenesis. © 2002 Wiley‐Liss, Inc.
Functional analysis of cis‐regulatory elements controlling initiation and maintenance of early Cdx1 gene expression in the mouse
Authors: Lickert Heiko , Kemler Rolf
Published: October 2002

Members of the Caudal‐related homeobox gene family are implicated in anteroposterior (AP) patterning and posterior axis elongation in mammals. Previously, we found that Caudal‐related homeobox gene1 (Cdx1) is directly regulated by the Wnt/β‐catenin signaling pathway, and we identified Wnt/β‐catenin responsive elements in the Cdx1 promoter. Here, we have generated a series of transgenic mouse lines to determine if the Cdx1 promoter region (−3.6 kb to −0.7 kb) sufficient to drive reporter gene expression in the normal Cdx1 expression domains. A 0.7‐kb Cdx1 upstream regulatory sequence is sufficient to give the early phase of Cdx1 expression in the primitive streak. However, none of the reporter constructs was able to drive expression in the definitive endoderm at later stages of development. More detailed analysis of the cis‐regulatory elements of this 0.7‐kb Cdx1 promoter region revealed that two Wnt/β‐catenin responsive elements are important for initiation of Cdx1 expression in the primitive streak and one retinoic acid response element for maintenance. Our analysis demonstrates that the early Cdx1 expression is regulated through the caudalizing Wnt/β‐catenin and RA activities. © 2002 Wiley‐Liss, Inc.
Effectiveness evaluation of shielding material in reducing electromagnetic interference of cardiac pacemaker induced by portable information terminals
Authors: Wang Jianqing , Ohshima Takeshi , Fujiwara Osamu
Published: October 2002

In order to guard continuously patients with a cardiac pacemaker from radio waves emitted by the portable information terminal, an effective way is to shield the human body electromagnetically with a shielding material. There remain many unknown points regarding the effectiveness of wearing the shielding material. The authors have proposed a model for estimating the electromagnetic interference (EMI) with the pacemaker as a receiving antenna. This paper applies the model to the qualitative evaluation of the EMI reduction produced by wearing the shielding material. The result of the proposed evaluation method is compared to the result of the conventional evaluation method, which is based on the reduction of the electromagnetic field in the torso not containing a pacemaker. It is found that, although the conventional method does not reflect exactly the true EMI reduction for the pacemaker, it is useful as a preliminary evaluation of the EMI level for the pacemaker. The elliptic cylinder torso model, composed of three layers of skin, fat, and muscle, is considered, and the reductions of the EMI level by the conductive and the magnetic sheets for the pacemaker are evaluated by the proposed method. The following results are obtained. When the antenna is placed at a distance of 1 cm from the torso, the EMI reduction effect of the magnetic material is equivalent to placing the antenna at 7 cm, and that of the conductive sheet is equivalent to placing the antenna at more than 20 cm. The latter result indicates that, even if the antenna approaches within 1 cm of the torso, the equivalent distance satisfying essentially the guideline (22 cm) of the Japanese Pacemaker Association is realized, if the conductive sheet is worn on the torso. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(1): 48–53, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10023
Performance analysis of RAKE receiver in W‐CDMA downlink
Authors: Hara Yoshitaka , Park Duk‐Kyu , Kamio Yukiyoshi
Published: October 2002

In this paper, we theoretically analyze the received signal performance during reception by a RAKE receiver at the terminal in wideband DS‐CDMA (W‐CDMA: wideband code division multiple access) downlink and evaluate the characteristics by a simulation. This theoretical analysis considers the long code and Walsh code used in the W‐CDMA downlink, signal transmission to many users, and transmission beamforming at the base station. We derive an exact solution of the signal‐to‐interference‐plus‐noise ratio (SINR) after RAKE reception at the terminal. In this process, the interference signals exhibit correlation between the RAKE fingers of the terminal in the W‐CDMA downlink. The simulation verifies the derived SINR equation. In addition, we evaluate the signal characteristics of the RAKE reception at the terminal in a fading environment and discuss the differences from the theoretical values. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(1): 24–37, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10037
An adaptive multipath estimation/elimination technique for GPS signals reception
Authors: Minami Masateru , Morikawa Hiroyuki , Aoyama Tomonori , Mizumachi Moriyuki
Published: October 2002

Recently, with advances in differential GPS (DGPS) technology, the measurement performance of GPS has improved significantly. In this environment, degradation of the measurement performance of GPS due to multipath error that cannot be eliminated by the DGPS technique is a serious problem. In this paper, as a multipath solution in GPS, multipath estimation is carried out with an adaptive filter based on the least squares method. A method is presented to reduce the locking error in code phase locking and carrier phase locking by eliminating the multipath effect from the received signal correlation. Also, by means of computer simulation, the effectiveness of the present method is confirmed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(1): 74–82, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1148
Performance evaluation of TCP over ABT protocols
Authors: Ata Shingo , Murata Masayuki , Miyahara Hideo
Published: October 2002

ABT (ATM block transfer) has been considered an efficient protocol for high‐burst data transmission in ATM networks. The characteristics of ABT in the ATM service class have already been investigated. For practical applications, however, it is necessary to consider an upper layer having its own congestion‐control mechanism, apart from the ABT. This paper analyzes the characteristics of a TCP (transmission‐control protocol) for the Internet which has become very popular recently, when this is used for the upper layer of the ABT. It is shown to be possible to separate the congestion control and the error‐recovery service, since the congestion control is carried out effectively in the ABT by the retransmission mechanism of TCP, without using the congestion control of TCP. However, for high performance it is necessary to tune the retransmission timer of the TCP as discussed in this paper. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(1): 97–104, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1150
Imaging simulation of near‐field optical scanning microscope: Comparison between dielectric probe and metal‐coated aperture probe
Authors: Yoshida Takahiro , Tanaka Kazuo , Tanaka Masahiro
Published: October 2002

In this paper, a simulation code for a two‐dimensional photon scanning tunneling microscope (PSTM) is created by using the boundary element method based on the guided‐mode extracted integral equation. Imaging simulation is carried out for the cases of a dielectric probe or a metal‐coated probe and observation objects that are multiple dielectrics or metals. In the simulation, the transmission coefficient of the guided mode in a collection mode probe with an incident TE wave (s polarization) and the reflection coefficient of the illumination mode for the incident fundamental TE mode are derived. By a probe scan, the relationship between the output image and the observation object is studied. It is shown that the output image contrast decreases and the effect of interference pattern increases with a metal‐coated aperture probe, whereas the image characteristics on the output image are improved relative to those obtained with a dielectric probe. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(10): 7–16, 2002; Published online in Wiley InterScienc (www.interscience.wiley.com). DOI 10.1002/ecjb.10050
Effects of the HEMT parameters on the operation frequency of resonant tunneling logic gate MOBILE
Authors: Aoyama Tomoko , Ohno Yutaka , Kishimoto Shigeru , Maezawa Koichi , Mizutani Takashi
Published: October 2002

A MOBILE is a high‐speed logic gate exploiting the negative differential resistance of resonant tunneling diodes (RTDs). It consists of two serially connected RTDs and HEMTs, connected to the RTD(s) in parallel. Effects of various parameters should be considered to realize ultrahigh‐speed operation of the MOBILE. In particular, the ratio of the gate width of the HEMTs to the RTD area is the most important parameter, and should be optimized. In this paper we discuss the effects of this parameter on the operation speed based on the results of the circuit simulation under practical conditions, and show that the small gate width is essential to high‐speed operation. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(10): 1–6, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10055
Estimation of camera parameters and compensation of image distortion by matching a priori known shape
Authors: Shibuya Yuichiro , Kumazawa Itsuo
Published: October 2002

This paper proposes a method for estimating position and pose of a camera by matching a picture of arbitrary known shape photographed by a camera and a template. In this method, since the three‐dimensional space and the observational image are matched by the global information of the picture, reading errors of the image can be prevented. Moreover, it can be expected that the camera parameters can be estimated in subpixel accuracy by compensating the deterioration of the edges using pixel representation of the picture in the global matching process. The distinctive feature of the proposed method is the use of a form description function in the description of the template. By doing so, the geometrical transformation can be performed easily without breaking down the shape of the picture, making it possible to apply the Gauss‐Newton method to the method of parameter estimation. Finally, the results of computer simulations are shown and the effectiveness of the proposed method is confirmed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(10): 40–50, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10088
From data to nonlinear dynamics: Time series prediction via hierarchical Bayes approach
Authors: Matsumoto Takashi , Hamagishi Hiroaki , Sugi Junjiro , Saito Motoki , Chonan Yoshimasa
Published: October 2002

In the framework of the hierarchical Bayesian approach, a method for nonlinear time series prediction using neural nets is proposed, and its particular applications are shown by examples. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(10): 71–83, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10091
Error detection capability for variable length codes
Authors: Chujoh Takeshi
Published: October 2002

In many practical systems using variable length codes, a bit stream format is adopted in which synchronous codes are inserted at a certain interval. With such a format, random access to the bit stream becomes possible. If there is an error, resynchronization is possible. In this paper, a method is proposed to quantitatively express the relationship of error detection due to decoding of nonexisting code words in the presence of errors with self‐synchronization by coincidence of the suffix of the code words in the variable length codes used in the above systems. As a model for the channel, the Gilbert model, a classical burst error model, and the binary symmetric channel are used for analysis. It is found that error detection and the self‐synchronization are in a trade‐off relationship and that the reversible variable length codes that are instantaneously decodable in both directions have a high level of error detection capability in the sense that the codes are not self‐synchronized. These results can be used for error resilient technique in coding systems using variable length codes. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 70–79, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10014
On universality of both Bayes codes and Ziv‐Lempel codes for sources which emit data sequence by block unit
Authors: Ishida Takashi , Gotoh Masayuki , Hirasawa Shigeichi
Published: October 2002

Ziv‐Lempel (ZL) codes and Bayes codes are typical universal codes. An improved algorithm of the ZL code is widely used in compression software. On the other hand, practical use of Bayes codes is difficult due to the large amount of computation needed. However, a realizable algorithm in terms of computation effort has been constructed for the FSMX model group9. In this paper, an information source generating a sequence by word units is assumed as a model that can represent the probabilistic structure of actual data such as text data. The asymptotic compression performance of both codes is analyzed and evaluated for the information source class (information source for the block unit) with a constant (fixed) word length. As a result, it is found that Bayes code cannot directly be universal as a coding algorithm for symbol units. On the other hand, the ZL78 code can be directly universal. Also, a configuration method for the Bayes coding method is given for an information source with a block unit. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 58–69, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10017
Segmentation of ultrasonic images by using locally adaptive filter and wavelet analysis: Detection of superficial peripheral vein by a high‐frequency ultrasonic equipment
Authors: Takemura Atsushi , Ito Masayasu
Published: October 2002

Ultrasonic diagnostic equipment is widely used, but has many problems such as acquiring noisy images and poorly quantifying the results for diagnosis. Therefore, a great deal of research has addressed the image processing of medical ultrasound images because of the need for automation and quantification of the diagnosis. This research began with the problem of region segmentation that automatically identifies living tissue or focus mass and currently relates to the quantification of tissue region information with the objective of tissue property diagnosis and the automatic diagnosis of 3D images. To achieve this, an accurate contour extraction method must be established. In this research, to achieve accurate region segmentation without losing the contour information in the medical ultrasound diagnostic images, we propose a new method based on an adaptive smoothing filter for suppressing speckle patterns and the 2D Gabor wavelet transform. Then we tried to automatically detect a superficial peripheral vein from an image of the forearm obtained by high‐frequency ultrasonic diagnostic equipment, which is a difficult problem for conventional image analysis techniques. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 36–45, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10026
Aliasing avoidance and reduction of computational complexity in Volterra filters
Authors: Kinoshita Satoshi , Kajikawa Yoshinobu , Nomura Yasuo
Published: October 2002

Since a speaker system has nonlinearity, it is necessary to place a nonlinear inverse system in front of the speaker system so that the nonlinear distortion is corrected. However, in realization with DSP, the amount of computation in the Volterra filter used in the nonlinear inverse system is enormous. There exists a region containing aliasing components in the output signal of the Volterra filter. There is a way to band‐limit the input signal in order to avoid aliasing. However, since the sampling frequency is set to twice the Nyquist frequency, an unnecessary band is processed and the efficiency is poor. Hence, in this paper, a configuration is proposed that does not cause aliasing even if the sampling frequency is chosen as the Nyquist frequency in order to reduce the amount of computation in the Volterra filter. Next, an identification method for the speaker system in order to efficiently obtain the Volterra filter used in the proposed configuration is presented. The proposed configuration is applied to the nonlinear inverse system. Finally, the effectiveness of the present method is demonstrated by simulation. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 19–26, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10031
Extraction of fuzzy clusters from weighted graphs
Authors: Hotta Seiji , Inoue Kohei , Urahama Kiichi
Published: October 2002

A type of graph spectral method is proposed in which the point ensemble is divided into fuzzy clusters based on a weighted adjoint matrix. In this method, the problem of extracting a fuzzy cluster from a point ensemble is formulated as an eigenvalue problem. This is repetitively applied so that clusters are extracted successively. First, the cluster extraction method based on the similarity matrix is applied to an undirected graph, which is then expanded to a digraph and an undirected bipartite graph, allowing the extraction of the link structure of the web page and image browsing search by keyword. Also, a type of graph drawing method is proposed in which the cluster structure is visualized by using correspondence analysis. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 80–88, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1133
EMTP simulation of SLF interrupting performance for two serially connected arcs with different arc parameters
Authors: Koshizuka Tadashi , Shinkai Takeshi , Nishiwaki Susumu , Yanabu Satoru , Kawaguchi Yoshihiro
Published: October 2002

This paper shows the calculation of SLF interrupting performance for two serially connected Mayr‐type arc models with different arc parameters by using EMTP‐ATP Models. Arc model 1, assuming an air circuit breaker, has large arc time constant and large arc power loss. Arc model 2, assuming a vacuum circuit breaker, has small arc time constant and small arc power loss. It was not possible for arc model 1 to interrupt 300 kV‐63 kA‐90% SLF by itself. However, by connecting these arc models in series, interruption became successful, even if arc model 2 was reignited at low voltage a few microseconds after current zero. These computations suggested that serial connection of the two circuit breakers with different breaking characteristics would give a totally excellent circuit breaker by making the best use of advantages of each circuit breaker. EMTP‐ATP Models were very useful in solving the arc models, which are expressed by differential equations and coupled with the electric circuit. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 25–33, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10020