bluuebunny/crossref_metadata_2025_split huggingface dataset:
Re‐evaluation of nestin as a marker of oligodendrocyte lineage cells
Authors: Almazán Guillermina , Vela José Miguel , Molina‐Holgado Eduardo , Guaza Carmen 
Published: August 2002

AbstractMaturation of oligodendrocyte progenitors (O2A) is characterized by morphological changes and the sequential expression of specific antigens leading to the formation of myelin membrane. Monoclonal antibodies A2B5, A007, anti‐vimentin, and anti‐galactocerebroside, recognize oligodendroglia at different stages of development. The neuroepithelial precursor marker nestin is also expressed by the oligodendroglial lineage; we have used enriched populations of progenitors isolated from neonatal rat brain cultures to further examine the cellular distribution of this intermediate filament protein. The phenotypic distribution of nestin positive cells among the oligodendrocyte lineage showed that 65% reacted with A2B5, whereas only 5% were A007+, and 4% galactocerebroside+. The remaining 25% of the cells were not labeled and had small cellular bodies devoid of processes, characteristic of the pre‐O2A progenitor. Further analysis of the nestin+ population showed that the majority of the cells were also vimentin+. Antibody‐dependent complement mediated cytolysis of A2B5+ (O2A cells) and galactocerebroside+ (mature oligodendrocytes) cells left a population of nestin+ cells that were induced to proliferate in the presence of growth factors and to differentiate into A2B5+ and galactocerebroside+ cells. Proliferating cells maintained in the presence of platelet‐derived growth factor or basic fibroblast growth factor retained nestin expression along with A2B5. By contrast, in serum‐free medium nestin expression decreased while postmitotic cells acquired A007 and galactocerebroside. Our results suggest that nestin expression is a marker of pre‐O2A cells that is maintained in proliferating glial progenitors, but is quickly down‐regulated in postmitotic oligodendrocytes (A007+/galacto‐cerebroside+) along with A2B5 and vimentin. However, other glial cells including type 2 astrocytes and some amoeboid microglia also share nestin expression. Microsc. Res. Tech. 52:753–765, 2001. © 2001 Wiley‐Liss, Inc.
Circadian organization and the role of the pineal in birds
Authors: Underwood Herbert , Steele Christopher T. , Zivkovic Bora 
Published: August 2002

AbstractAll organisms exhibit significant daily rhythms in a myriad of functions from molecular levels to the level of the whole organism. Significantly, most of these rhythms will persist under constant conditions, showing that they are driven by an internal circadian clock. In birds the circadian system is composed of several interacting sites, each of which may contain a circadian clock. These sites include the pineal organ, the suprachiasmatic nucleus (SCN) of the hypothalamus, and, in some species, the eyes. Light is the most powerful entraining stimulus for circadian rhythms and, in birds, light can affect the system via three different pathways: the eyes, the pineal, and extraretinal photoreceptors located in the deep brain. Circadian pacemakers in the pineal and in the eyes of some avian species communicate with the hypothalamic pacemakers via the rhythmic synthesis and release of the hormone melatonin. Often the hypothalamic pacemakers are unable to sustain persistent rhythmicity in constant conditions in the absence of periodic melatonin input from the pineal (or eyes). It has also been proposed that pineal pacemakers may be unable to sustain rhythmicity in constant conditions without periodic neural input from the SCN. Significant variation can occur among birds in the relative roles that the pineal, the SCN, and the eyes play within the circadian system; for example, in the house sparrow pacemakers in the pineal play the predominant role, in the pigeon circadian pacemakers in both the pineal and eyes play a significant role, and in Japanese quail ocular pacemakers play the predominant role. Microsc. Res. Tech. 53:48–62, 2001. © 2001 Wiley‐Liss, Inc.
Catecholaminergic and acetylcholine esterase containing nerves of cranial and spinal dura mater in humans and rodents
Authors: Artico Marco , Cavallotti Carlo 
Published: August 2002

AbstractThe innervation of cranial and spinal dura mater in humans and rodents was studied by examining several dural zones (vascular, perivascular, intervascular) in different regions. Characterization and distribution of dural acetylcholinesterase‐positive nerve fibers, catecholaminergic nerve fibers, and mast cells are analyzed and discussed. The results of chemical and surgical sympathectomy as well as the relationships between catecholaminergic nerve fibers and mast cells are studied. Our results are discussed in the light of possible implications in the physiopathology of dural algic syndromes including cephalalgia and spinal pain. Microsc. Res. Tech. 53:212–220, 2001. © 2001 Wiley‐Liss, Inc.
Effects of age and GDNF on noradrenergic innervation of the hippocampal formation: Studies from intraocular grafts
Authors: Granholm A.‐C. , Helt C. , Srivastava N. , Backman C. , Gerhardt G.A. 
Published: August 2002

AbstractRecent studies have suggested that factors in the target tissue influence the degree of plasticity and regeneration following aging and/or specific insults. We have investigated whether young or aged targets differ in their noradrenergic innervation from fetal locus coeruleus (LC) neurons, and also if a specific growth factor, glial cell line‐derived neurotrophic factor (GDNF) can affect this innervation pattern. Tissue pieces of fetal brainstem and young (3 months) or old (18 months) iris tissue were transplanted simultaneously into the anterior chamber of the eye of adult hosts. We found that aged iris transplants became innervated to a significantly lesser degree by the cografted LC neurons than young iris transplants. Fetal hippocampal tissue was then grafted to adult hosts, and a fetal brainstem graft containing LC neurons was placed adjacent to the first graft, either at 3 or 21 months post‐grafting. Thus, old/young chimeras of the noradrenergic coeruleo‐hippocampal pathway were created. Aged hippocampal grafts received a much less dense innervation from co‐grafted LC neurons than young hippocampal grafts. Tyrosine hydroxylase‐positive‐immunoreactive innervation was only found in the outskirts of aged grafts, while the young hippocampal grafts contained an even innervation pattern. The innervation density of hippocampal grafts was significantly enhanced by GDNF treatment. These findings demonstrate that target‐derived factors may regulate neuronal plasticity, and that the age of the target is more important for innervation properties than the age of the neuron innervating a particular target. Microsc. Res. Tech. 54:298–308, 2001. © 2001 Wiley‐Liss, Inc.
Deduced primary structure of vitellogenin in the giant freshwater prawn, Macrobrachium rosenbergii, and yolk processing during ovarian maturation
Authors: Okuno Atsuro , Yang Wei‐Jun , Jayasankar Vidya , Saido‐Sakanaka Hisako , Huong Do Thi Thanh , Jasmani Safiah , Atmomarsono Muharijadi , Subramoniam Thanumalayaperumal , Tsutsui Naoaki , Ohira Tsuyoshi , Kawazoe Ichiro , Aida Katsumi , Wilder Marcy N. 
Published: August 2002

AbstractA cDNA encoding vitellogenin (Vg) in the giant freshwater prawn, Macrobrachium rosenbergii, was cloned based on the cDNA sequence of vitellin (Vn) fragments A‐N and B‐42 determined previously, and its amino acid sequence deduced. The open reading frame (ORF) encoded 2,537 amino acid residues and its deduced amino acid sequence possessed three consensus cleavage sites, R‐X‐R‐R, similar to those reported in Vgs of insects. The deduced primary structure of Vg in M. rosenbergii was seen to be similar to that of Penaeus japonicus, especially in the N‐terminal region. It is therefore likely that Vgs in crustacean species including prawns and other related decapods exhibit a similar structural pattern. Based on the deduced primary structure of Vg and analysis of the various Vg and Vn subunits found in the hemolymph and ovary during ovarian maturation, we demonstrated the post‐translational processing of Vg in M. rosenbergii. This is the first time that Vg processing has been clearly demonstrated in a crustacean species. Vg, after being synthesized in the hepatopancreas, is considered to be cleaved by a subtilisin‐like endoprotease to form two subunits, A and proB, which are then released into the hemolymph. In the hemolymph, proB is possibly cleaved by a processing enzyme of unknown identity to give rise to subunits B and C/D. The three processed subunits A, B, and C/D are sequestered by the ovary to give rise to three yolk proteins, Macr‐VnA, VnB, and VnC/D. J. Exp. Zool. 292:417–429, 2002. © 2002 Wiley‐Liss, Inc.
Macro‐evolution of the hairy enhancer in Drosophila species
Authors: Kim Junhyong 
Published: August 2002

AbstractIt has been suggested that many of the changes in the developmental program might be in the cis‐acting promoters and enhancer regions. Here I study the macro‐evolutionary changes of an enhancer region for the early developmental gene hairy in Drosophila melanogaster, D. simulans, D. pseudoobscura, D. willistoni, D. nebulosa, D. hydei, and D. virilis. The enhancer region is characterized by small, highly conserved blocks interspersed among highly variable regions. Nevertheless, species phylogenies constructed by the enhancer sequences agree with the widely accepted phylogeny of these species. The evolution of the variable regions is consistent with a molecular clock, while the evolution of the conserved blocks is significantly different from a clock. In particular, the D. pseudoobscura lineage shows the highest degree of species‐specific change consistent with changes in expression timing reported in an earlier study. It has been suggested that the variation in sequence length between highly conserved blocks may play a role in the coordination of regulatory processes, such as protein–protein interactions; thus, stabilizing selection has been suggested to act on the length variations. Here I develop a test for stabilizing selection on length variation and show that the hairy enhancer does not show statistically significant evidence for stabilizing selection. J. Exp. Zool. (Mol. Dev. Evol.) 291:175–185, 2001. © 2001 Wiley‐Liss, Inc.
The tetrapod limb: A hypothesis on its origin
Authors: Wagner Günter P. , Chiu Chi‐Hua 
Published: August 2002

Abstract
A wrist joint and structures typical of the hand, such as digits, however, are absent in [Eustenopteron] (Andrews and Westoll, ’68, p 240).Great changes must have been undergone during evolution of the ankle joint; the small number of large bones in the fin must somehow have developed into a large number of small bones, and it is very difficult to draw homologies in this region, or even be certain of what is being compared (Andrews and Westoll, ’68, p 268).
The tetrapod limb is one of the major morphological adaptations that facilitated the transition from an aquatic to a terrestrial lifestyle in vertebrate evolution. We review the paleontological evidence for the fin‐limb transition and conclude that the innovation associated with evolution of the tetrapod limb is the zeugopodial‐mesopodial transition, i.e., the evolution of the developmental mechanism that differentiates the distal parts of the limb (the autopodium, i.e., hand or foot) from the proximal parts. Based on a review of tetrapod limb and fish fin development, we propose a genetic hypothesis for the origin of the autopodium. In tetrapods the genes Hoxa‐11 and Hoxa‐13 have locally exclusive expression domains along the proximal‐distal axis of the limb bud. The junction between the distal limit of Hoxa‐11 expression and of the proximal limit of Hoxa‐13 expression is involved in establishing the border between the zeugopodial and autopodial anlagen. In zebrafish, the expression domains of these genes are overlapping and there is no evidence for an autopodial equivalent in the fin skeleton. We propose that the evolution of the derived expression patterns of Hoxa‐11 and Hoxa‐13 may be causally involved in the origin of the tetrapod limb. J. Exp. Zool. (Mol. Dev. Evol.) 291:226–240, 2001. © 2001 Wiley‐Liss, Inc.
Codiameters of 3‐connected 3‐domination critical graphs
Authors: Chen Yaojun , Tian Feng , Wei Bing 
Published: August 2002

AbstractA graph G is 3‐domination critical if its domination number γ is 3 and the addition of any edge decreases γ by 1. Let G be a 3‐connected 3‐domination critical graph of order n. In this paper, we show that there is a path of length at least n−2 between any two distinct vertices in G and the lower bound is sharp. © 2002 John Wiley & Sons, Inc. J Graph Theory 39: 76–85, 2002
Managing multinationals: the governance of investment for the environment
Authors: Newell Peter 
Published: August 2002

AbstractThis paper explores the possibilities and limitations of different approaches to the regulation of transnational corporations in a context of globalization. Looking at environmental initiatives in particular, the paper considers the pros and cons of emerging public and private strategies for promoting corporate responsibility from a development perspective. The role of ‘civil regulation’, litigation against companies, and international legal instruments are assessed in this light. It is argued that each of these approaches, while not necessarily complementary, has a role to play in promoting positive investment strategies and deterring irresponsible investment practices in developing countries. Copyright © 2001 John Wiley & Sons, Ltd.
Wired for change: the links between ICTs and development discourses
Authors: Schech Susanne 
Published: August 2002

AbstractThe ICT revolution's promises and threats for developing countries can be brought into clearer perspective if we pay attention to the underlying discourses on development and knowledge employed in this debate. This paper suggests that those who enthusiastically embrace ICTs tend to operate within a modernization discourse, while sceptics are influenced by dependency and post‐colonial discourses of development. Both perspectives operate with a liberal notion of knowledge as separate from power. The paper argues that a more fruitful approach is to analyse the role ICTs play in the power–knowledge nexus. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis of ring‐14C‐labelled 4(3′‐, 6′‐dimethyl‐3′‐heptyl)‐phenol
Authors: Lalah J. O. , Lenoir D. , Henkelmann B. , Hertkorn N. , Günther K. , Schramm K.‐W. , Kettrup A. 
Published: August 2002

AbstractRing‐14C‐labelled 4(3′‐, 6′‐, dimethyl‐3′‐,heptyl)‐phenol (NP), an isomer of paranonyl phenol was synthesized for use in aquatic toxicity and metabolism studies. A very efficient method involving alkylation of ring‐14C‐labelled anisole and tertiary alkyl bromide (3‐bromo‐3,6‐dimethyl heptane) with AlCl3 followed by cleavage of the resultant ether with BBr3 was used giving a 24% yield ring labelled 14C‐NP (specific activity: 16.205 MBq/mg and purity >95% by HPLC) after TLC separation. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of N‐(2‐chloro‐5‐methylthiophenyl)‐ N′‐(3‐methyl‐thiophenyl)‐ N′‐[3H3]methylguanidine, {[3H3]CNS‐5161}
Authors: Gibbs Andrew R. , Morimoto Hiromi , VanBrocklin Henry F. , Williams Philip G. , Biegon Anat 
Published: August 2002

AbstractThe preparation of the title compound, [3H3]CNS‐5161, was accomplished in three steps starting with the production of [3H3]iodomethane (CT3I). The intermediate N‐[3H3]methyl‐3‐(thiomethylphenyl)cyanamide was prepared in 77% yield by the addition of CT3I to 3‐(thiomethylphenyl)cyanamide, previously treated with sodium hydride. Reaction of this tritiated intermediate with 2‐chloro‐5‐thiomethylaniline hydrochloride formed the guanidine compound [3H3]CNS‐5161. Purification by HPLC gave the desired labeled product in an overall yield of 9% with >96% radiochemical purity and a final specific activity of 66 Ci mmol−1. Copyright © 2002 John Wiley & Sons, Ltd.
Evidence for a DNA triplex in a recombination‐like motif: I. Recognition of Watson–Crick base pairs by natural bases in a high‐stability triplex
Authors: Walter Axel , Schütz Holger , Simon Hannelore , Birch‐Hirschfeld Eckhard 
Published: August 2002

AbstractData are presented on a triplex type with two parallel homologous strands for which triplex formation is almost as strong as duplex formation at least for some sequences and even at pH 7 and 0.2 MNaCl. The evidence mainly rests upon comparing thermodynamic properties of similar systems. A paperclip oligonucleotide d(A12C4T12C4A12) with two linkers C4obviously can form a triplex with parallel back‐folded adenine strand regions, because the single melting transition of this complex splits in two transitions by introducing mismatches only in the third strand region. Respectively, a hairpin duplex d(A12C4T12) and a single strand d(A12) form a triplex as a 1:1 complex in which the second adenine strand is parallel oriented to the homologous one in the Watson–Crick paired duplex. In this system the melting temperatureTmof the triplex is practically the same as that of the duplex d(A12)·d(T12), at least within a complex concentration range of 0.2–4.0 µM. The melting behaviour of complexes between triplex stabilizing ligand BePI and the system hairpin duplex plus single strand supports the triplex model. Non‐denaturing gel electrophoresis suggests the existence of a triplex for a system in which five of the twelve A·T*A base triads are substituted by C·G*C base triads.  The recognition between any substituted Watson–Crick base pair (X·Y) in the hairpin duplex d(A4XA7C4T7YT4) and the correspondingly replaced base (Z) in the third strand d(A4ZA7) is mutually selective. All triplexes with matching base substitutions (Z = X) have nearly the same stability (Tmvalues from 29 to 33.5°C), whereas triplexes with non‐matching substitutions (Z ≠ X) show a clearly reduced stability (Tmvalues from 15 to 22°C) at 2µMequimolar oligonucleotide concentration. Most nucleic acid triple helices hitherto known are limited to homopurine–homopyrimidine sequences in the target duplex. A stable triplex formation is demonstrated for inhomogeneous sequences tolerating at least 50% pyrimidine content in the homologous strands. On the basis of the surprisingly similar thermodynamic parameters for duplex and triplex, and of the fact that this triplex type seems to be more stable than many other natural DNA triplexes known, and on the basis of semiempirical and molecule mechanical calculations, we postulate bridging interactions of the third strand with the two other strands in the triplex according to the recombination motif. This triplex, denoted by us ‘recombination‐like form’, tolerates heterogeneous base sequences. Copyright © 2001 John Wiley & Sons, Ltd.Abbreviations used:CDcircular dichroismDFdegrees of freedomTFOtriplex‐forming oligonucleotide.
Assessment of tumor oxygenation in human cervical carcinoma by use of dynamic Gd‐DTPA‐enhanced MR imaging
Authors: Lyng Heidi , Vorren Ann O. , Sundfør Kolbein , Taksdal Ingeborg , Lien Hans H. , Kaalhus Olav , Rofstad Einar K. 
Published: August 2002

AbstractIncreased knowledge of the physiological basis behind the signal enhancement in tumors during dynamic contrast‐enhanced magnetic resonance (MR) imaging may be useful in development of predictive assays based on this technique. In the present work, the relative signal intensity (RSI) increase in gadopentetate dimeglumine (Gd‐DTPA)‐enhanced MR images of patients with cervical carcinoma was related to tumor perfusion, vascular density, cell density, and oxygen tension (pO2). The patients were subjected to MR imaging before the start of treatment (N = 12) and after two weeks of radiotherapy (N = 8). Perfusion was determined from the kinetics of contrast agent in tumors and arteries, vascular density and cell density were determined from tumor biopsies, and pO2 was determined by polarographic needle electrodes. The maximal RSI was correlated to perfusion (P = 0.002) and cell density (P = 0.004), but was not related to vascular density. There was also a correlation between pO2 and perfusion (P < 0.001). Moreover, pO2 tended to be correlated to cell density (P = 0.1), but was not related to vascular density. There was a significant correlation between RSI and pO2, regardless of whether the median pO2 (P < 0.001) or the fraction of pO2 readings below 2.5 mmHg (P < 0.001), 5 mmHg (P < 0.0001), or 10 mmHg (P < 0.001) was considered. Our results suggest that the Gd‐DTPA‐induced signal enhancement in MR images of cervical tumors is influenced by both perfusion and cell density. These parameters are also of major importance for tumor oxygenation, leading to a correlation between signal enhancement and oxygenation. Dynamic contrast‐enhanced MR imaging may therefore possibly be useful in prediction of treatment outcome. J. Magn. Reson. Imaging 2001;14:750–756. © 2001 Wiley‐Liss, Inc.
Comparison of two volumetric techniques for estimating liver volume using magnetic resonance imaging
Authors: Mazonakis Michael , Damilakis John , Maris Thomas , Prassopoulos Panos , Gourtsoyiannis Nicholas 
Published: August 2002

AbstractPurposeTo compare the conventional technique of manual planimetry with the point counting technique for estimating liver volume from magnetic resonance imaging (MRI) data.Materials and MethodsThis study comprised abdominal MR examinations of 38 consecutive patients. Evaluation of the images showed that liver size appeared normal in 27 patients and increased in 11. Liver volume was estimated using the techniques of planimetry and point counting. Both techniques were used in combination with the Cavalieri method of modern design stereology. A systematic slice sampling procedure was performed to estimate liver volumes using both volumetric techniques. The point counting technique was optimized by altering the point spacing of the grid. The agreement between the two techniques was found. Measurement repeatability of both volumetric techniques was also evaluated.ResultsBoth techniques allowed the same degree of optimization through the procedure of systematic section sampling. The application of a point spacing of 2.5 cm reduced the time measurement by a factor of 3.5 in relation with the time needed with planimetry. An excellent agreement was observed between the two volumetric techniques with mean differences (±SD) of 2.4 ± 41.6 cm3 and 8.5 ± 49.8 cm3 for the patients presenting normal and increased liver sizes, respectively. Both techniques were highly reproducible.ConclusionThe point counting technique could be considered a more efficient approach than planimetry for estimating liver volume from MRI, due to its speed and simplicity. J. Magn. Reson. Imaging 2002;15:557–563. © 2002 Wiley‐Liss, Inc.
Fetal shoulder measurements by fast and ultrafast MRI techniques
Authors: Tukeva Timo A. , Salmi Hanna , Poutanen Veli‐Pekka , Karjalainen Pertti T. , Hytinantti Timo , Paavonen Jorma , Teramo Kari A. , Aronen Hannu J. 
Published: August 2002

AbstractThe purpose of this study was to evaluate magnetic resonance imaging (MRI) of fetal shoulder measurements of fetuses with suspected macrosomia. The actual fetal shoulder measurements made immediately after birth were compared with measurements obtained by fast and ultrafast MRI techniques antepartum. Eight singleton diabetic pregnant mothers underwent MRI examination with fast imaging in steady‐state precession (TrueFISP) and spin‐echo (SE) and gradient‐echo (GE) echo‐planar (EPI) sequences to show the fetal shoulder width. The actual shoulder width was measured immediately postpartum by a neonatologist. There was a statistically significant correlation between the MRI measurements and the actual shoulder width (P < 0.001 – P < 0.05) for all sequences. TrueFISP (r = 0.98, P < 0.001) was superior to EPI sequences (r = 0.88, P < 0.01 for SE EPI and r = 0.80, P < 0.05 for GE EPI). The images of all three sequences used were free of major motion artifacts. Fast and ultrafast sequences seem to be reliable for fetal shoulder measurements and the TrueFISP was the most accurate sequence compared to SE and GE echo‐planar sequences. J. Magn. Reson. Imaging 2001;13:938–942. © 2001 Wiley‐Liss, Inc.