bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular approach to echinoderm regeneration
Authors: Thorndyke Michael C. , Chen Wei‐Chung , Beesley Philip W. , Patruno Marco 
Published: August 2002

AbstractUntil very recently echinoderm regeneration research and indeed echinoderm research in general has suffered because of the lack of critical mass. In terms of molecular studies of regeneration, echinoderms in particular have lagged behind other groups in this respect. This is in sharp contrast to the major advances achieved with molecular and genetic techniques in the study of embryonic development in echinoderms. The aim of our studies has been to identify genes involved in the process of regeneration and in particular neural regeneration in different echinoderm species. Our survey included the asteroidAsterias rubensand provided evidence for the expression ofHoxgene homologues in regenerating radial nerve cords. Present evidence suggests: 1)ArHox1expression is maintained in intact radial nerve cord and may be upregulated during regeneration. 2)ArHox1expression may contribute to the dedifferentiation and/or cell proliferation process during epimorphic regeneration. From the crinoidAntedon bifida, we have been successful in cloning a fragment of a BMP2/4 homologue (AnBMP2/4) and analysing its expression during arm regeneration. Here, we discuss the importance of this family of growth factors in several regulatory spheres, including maintaining the identity of pluripotent blastemal cells or as a classic skeletal morphogenic regulator. There is clearly substantial scope for future echinoderm research in the area of molecular biology and certain aspects are discussed in this review. Microsc. Res. Tech. 55:474–485, 2001. © 2001 Wiley‐Liss, Inc.
Presence of thyroid hormones in ascidian larvae and their involvement in metamorphosis
Authors: Patricolo Eleonora , Cammarata Matteo , D’Agati Paolo 
Published: August 2002

AbstractIn this study we investigated the presence and localization of thyroxine in Ciona intestinalis larvae and its involvement in metamorphosis. To date, the mechanisms regulating the metamorphosis of ascidians remain largely unknown. In vivo treatment of swimming larvae with exogenous L‐thyroxine and thiourea, and in vitro experiments utilizing high performance liquid chromatography, radioimmunoassay, and immunoperoxidase staining demonstrate the presence of thyroxine at the larval stage. This suggests that this hormone may participate in the control of metamorphosis and thus play a different role from that observed in adults. J. Exp. Zool. 290:426–430, 2001. © 2001 Wiley‐Liss, Inc.
Temporal control of DNA replication and the adaptive value of chromatin diminution in copepods
Authors: Wyngaard Grace A. , Gregory T. Ryan 
Published: August 2002

AbstractChromatin diminution is a precisely controlled, highly repeatable, genome‐wide deletion of noncoding heterochromatic segments from the presomatic line. The somatic line is reduced in size and reorganized; the germ line remains unaltered. Little is understood about its mechanistic underpinnings and adaptive significance in the nematodes, copepods, and hagfish in which it occurs. Here, we propose that microcrustacean copepods, whose cytology, development, and evolutionary ecology are well understood from an adaptationist point of view, provide the vehicle to test how chromatin diminution might orchestrate certain cell cycle dynamics, with the consequence of influencing the evolution of nuclear DNA contents, organismal development rates, and body size. J. Exp. Zool. (Mol. Dev. Evol.) 291:310–316, 2001. © 2001 Wiley‐Liss, Inc.
Sperm storage in turtles: A male perspective
Authors: Gist Daniel H. , Dawes Sue M. , Turner Terry W. , Sheldon Susannah , Congdon J. D. 
Published: August 2002

AbstractThe storage and behavior of sperm collected from the epididymis of two emyiid turtles were examined. In Chrysemys picta, the weight of the epididymis does not change significantly throughout the year as does the testis. However, in this species, as well as in Trachemys scripta, the epididymis contains sperm throughout the entire year. Sperm from both species have a relatively low motility and velocity of movement. In C. picta, equally low motilities are observed both in the autumn, shortly after spermiation, and in spring. Motility could be augmented by the addition of isobutyl methyl xanthine (IBMX, 0.5 mmol l–1). Epididymal sperm remained viable in excess of 40 days in vitro when stored in F‐10 buffer, during which time motility and swimming velocity could be augmented with IBMX. The longevity and low motility of turtle sperm facilitates its storage by either males or females, and creates conditions that promote the wide dissemination, over time, of gametes produced in a narrow time window. J. Exp. Zool. 292:180–186, 2002. © 2002 Wiley‐Liss, Inc.
Side‐effects of a systemic injection of linear polyethylenimine–DNA complexes
Authors: Chollet Patrice , Favrot Marie C. , Hurbin A. , Coll Jean‐Luc 
Published: August 2002

AbstractBackgroundSystemic administration of linear polyethylenimine–DNA complexes (L‐PEI/DNA) results in transient expression of the transgene in the lung. This study analyzes the side‐effects associated with L‐PEI‐mediated transfection.MethodsMice weighing from 16 to 25 g received increasing amounts of L‐PEI/DNA intravenously. Gene expression was evaluated using luciferase as a reporter gene. Toxicity was evaluated by monitoring the appearance of shock after injection, the survival of the animals, and the microscopic damage in the tissues. Adherence of blood cells and endothelium activation were observed after CD11‐b and von Willebrand immunostaining. Anti‐aggregant treatments were used in order to prevent the formation of thrombi.ResultsIncreasing the quantity of L‐PEI/DNA resulted in a marked augmentation of the luciferase activity in the lung, but was associated with liver necrosis and death. Lethality was reached at lower doses in older mice, suggesting an age influence. Transfection was associated with activation of the lung endothelium and increased adhesion of small aggregates containing platelets and CD11‐b‐positive cells, without the appearance of large thrombi and of lung injury. Anti‐aggregant treatments (aspirin, EDTA, heparin or clopidogrel) decreased the L‐PEI‐mediated transfection, supporting the hypothesis that platelets participate in the blocking of DNA complexes in the lung capillaries.ConclusionThis study demonstrates that L‐PEI/DNA activates the lung endothelium and forms small aggregates, a side‐effect linked to the transfection efficiency. Copyright © 2001 John Wiley & Sons, Ltd.
Perceptions of poverty among poor livestock keepers in Kenya: a discourse analysis approach
Authors: Misturelli Federica , Heffernan Claire 
Published: August 2002

AbstractThe paper examines perceptions of poverty among poor livestock keepers in Kenya. The study utilized discourse analysis techniques to evaluate community values towards the poor. The results demonstrated that most study participants viewed poverty as a process rather than a permanent state. The findings also highlighted the differences between the rich and the poor in terms of capabilities. When the results were compared with a wealth ranking exercise, two types of bias were noted. First, wealth‐ranking exercises may not be targeting those who are the most needy. Second, projects and programmes may be viewed as assisting those who are responsible for their own poverty. Copyright © 2001 John Wiley & Sons, Ltd.
Radiosynthesis of (±)‐(2‐((4‐(2‐[18F]fluoro‐ethoxy)phenyl)bis(4‐methoxy‐phenyl)methoxy)ethylpiperidine‐3‐carboxylic acid: a potential GAT‐3 PET ligand to study GABAergic neuro‐transmission in vivo
Authors: Schirrmacher Ralf , Hamkens Wilhelm , Piel Markus , Schmitt Ulrich , Lüddens Hartmut , Hiemke Christoph , Rösch Frank 
Published: August 2002

AbstractA dysfunction of GABAergic neurotransmission is related to diseases such as epilepsy, Huntington‐disease and Parkinson‐syndrome. A new 18F‐fluorine labelled GABA transporter ligand for the GABA‐transporter subtype GAT‐3 was developed which may allow the in vivo visualisation of GABAergic neurotransmission. The precursors ethyl (2‐(4‐hydroxyphenyl)bis(4‐methoxyphenyl)‐methoxy)ethyl)‐piperidine‐3‐carboxylate and ethyl(2‐((4‐(2‐tosylethoxy)phenyl)‐bis(4‐methoxyphenyl)‐methoxy) ethyl)‐piperidine3‐carboxylate were synthesised and labelled by the use of 2‐[18F]fluoroethyltosylate or [18F]fluoride. Subsequent cleavage of the ester moiety gave the final product (±)‐(2‐((4‐(2‐[18F]fluoroethoxy)phenyl)bis(4‐methoxy‐phenyl)methoxy)ethyl)piperidine‐3‐carboxylic acid in a decay corrected yield of 33–36%. Preliminary biodistribution kinetics were determined with BALB/c mice ex vivo for brain, liver, kidney, spleen, blood and bone. (2‐((4‐(2‐[18F]fluoroethoxy)‐phenyl)bis(4‐methoxyphenyl)methoxy)‐ethyl) piperidine‐3‐carboxylic acid showed a maximum brain uptake after 1 h p.i. of about 0.3% ID/g. Copyright © 2001 John Wiley & Sons, Ltd.
Carbon‐11 labelling of MADAM in two different positions: a highly selective PET radioligand for the serotonin transporter
Authors: Tarkiainen Jari , Vercouillie Johnny , Emond Patrick , Sandell Johan , hiltunen Jukka , Frangin Yves , Guilloteau Denis , Halldin Christer 
Published: August 2002

AbstractImaging by scintigraphy the serotonin transporter (5‐HTT) in the living human brain would be of great value in research on the pathophysiology and treatment of neuropsychiatric disorders such as depression. For that reason, and in order to obtain a selective radiotracer applicable to PET, we report here the carbon‐11 labelling of a selective 5‐HTT radioligand: N, N‐dimethyl‐2‐(2‐amino‐4‐methylphenylthio)benzylamine or MADAM in two different positions: [p‐11C‐methyl]MADAM and [N‐11C‐methyl]MADAM. The synthesis of Bu3Sn‐ADAM and N‐dimethyl‐MADAM is described. [p‐11C‐methyl]MADAM was obtained by a Stille coupling reaction between Bu3Sn‐ADAM and [11C]methyl iodide using palladium (0) as a catalyst without (Ia) or with copper chloride as a co‐catalyst (Ib). [N‐11C‐methyl]MADAM was obtained by an N‐methylation reaction between N‐demethyl‐MADAM and [11C]methyl iodide (II). The carbon‐11 incorporation yield in [p‐11C‐methyl]MADAM was 10–30% (Ia and Ib) and in [N‐11C‐methyl]MADAM was 75‐80% (II). The final product in each case was obtained in 30 min total synthesis time, including HPLC purification and with >99% radiochemical purity. Copyright © 2001 John Wiley & Sons, Ltd.
The endocrine cells in the gastroenteropancreatic system of the bowfin, Amia calva L.: An immunohistochemical, ultrastructural, and immunocytochemical analysis
Authors: Youson John H. , Al‐Mahrouki Azza A. , Naumovski Diana , Conlon J. Michael 
Published: August 2002

AbstractThe gastroenteropancreatic (GEP) endocrine system of bowfin (Amia calva) was described using light and electron microscopy and immunological methods. The islet organ (endocrine pancreas) consists of diffusely scattered, mostly small islets and isolated patches of cells among and within the exocrine acini. The islets are composed of abundant, centrally located B cells immunoreactive to bovine and lamprey insulin antisera and D cells showing a widespread distribution and specificity to somatostatin antibodies. A and F cells are present at the very periphery of the islets and are immunoreactive with antisera against glucagon (and glucagon‐like peptide) and several peptides of the pancreatic polypeptide (PP)‐family, respectively. The peptides of the two families usually collocates within the same peripheral islet cells and are the most common immunoreactive peptides present in the extra‐islet tissue. Immunocytochemistry and fine structural observations characterised the granule morphology for B and D cells and identified two cell types with granules immunoreactive to glucagon antisera. These two putative A cells had similar granules, which were distinct from either B or D cells, but one of the cells had rod‐shaped cytoplasmic inclusions within cisternae of what appeared to be rough endoplasmic reticulum. The inclusions were not immunoreactive to either insulin or glucagon antisera. Only small numbers of cells in the stomach and intestine immunoreacted to antisera against somatostatin, glucagon, and PP‐family peptides. The paucity of these cells was reflected in the low concentrations of these peptides in intestinal extracts. The GEP system of bowfin is not unlike that of other actinopterygian fishes, but there are some marked differences that may reflect the antiquity of this system and/or may be a consequence of the ontogeny of this system in this species. J. Morphol. 250:208–224, 2001. © 2001 Wiley‐Liss, Inc.
Head structures ofPriacma serrataleconte (coleptera, archostemata) inferred from X‐ray tomography
Authors: Hörnschemeyer Thomas , Beutel Rolf G. , Pasop Freek 
Published: August 2002

AbstractInternal and external features of the head ofPriacma serratawere studied with X‐ray microtomography and with histological methods. The comparison of both techniques shows that X‐ray tomography is a promising new technique for the investigation of insect anatomy. The still somewhat coarse resolution of the X‐ray data is compensated for by advantages like the nondestructive and artifact‐free data acquisition. The head ofP. serrataand other adults of Archostemata is characterized by many derived features. Muscular features ofPriacma, especially muscles of the labium and pharynx, differ strongly from what is found in other groups of Coleoptera. Several character states are considered as autapomorphies of Archostemata: scale‐like surface structures, constricted neck, strongly reduced tentorium, and the plate‐like, enlarged prementum. The scales provide a protecting surface pattern and may have evolved with a more exposed lifestyle. The enlarged prementum forms a lid, which closes the mouth and covers the ligula when it is pulled back by contraction of the unusually strong submento‐premental muscle. The presence of four cone‐shaped protuberances on the dorsal side of the head is considered an autapomorphy of Cupedidae. The galea with a narrow stalk and a round and pubescent distal galeomere is another autapomorphy of this family. It has probably evolved as an adaptation to pollen‐feeding. The shape of the mandible of Cupedidae is plesiomorphic compared to what is found in adults of Ommatidae. The vertical arrangement of apical teeth is an autapomorphy of the latter family. The lateral insertion of the antenna inPriacmais a groundplan feature of Cupedidae. The dorsal shift is a synapomorphy of all other cupedid genera. A cladistic analysis of characters of the head and additional data resulted in the following branching pattern: ((Crowsoniella + (Omma + Tetraphalerus)) + (Micromalthus + (Priacma + (Paracupes + (Cupes + Tenomerga + Prolixocupes + Rhipsideigma + Distocupes + (Adinolepis + Ascioplaga)))))). J. Morphol. 252:298–314, 2002. © 2002 Wiley‐Liss, Inc.
FAST sequences optimization for contrast media pharmacokinetic quantification in tissue
Authors: Ivancevic Marko K. , Zimine Ivan , Lazeyras François , Foxall David , Vallée Jean‐Paul 
Published: August 2002

AbstractThe purpose of this study was to investigate the influence of the fast gradient‐recalled echo (GRE) sequence parameters on the contrast dynamic range and signal sensitivity, to optimize the magnetic resonance (MR) sequence for contrast media pharmacokinetic assessment. Effects of the fast low‐angle shot (FLASH), Fast acquisition at steady rate (FAST), and radiofrequency‐spoiled (RF)‐FAST sequence parameters were studied in vitro. The FAST sequence had the highest sensitivity in low gadolinium (Gd) concentration. The FLASH and RF‐FAST sequences had a larger contrast dynamic range, but the FLASH images contained side band artifacts. Increasing the flip angle to 90° raised the sensitivity of the FAST sequence and the contrast dynamic range of the RF‐FAST sequence. The shortest possible TE was optimal for both contrast dynamics and imaging time. TI had an influence on the sensitivity of the FAST sequence only for small acquisition matrices. This study indicates the optimal parameters for contrast dynamics (RF‐FAST, 90° flip angle, shortest possible TE) and sensitivity (FAST, 90° flip angle, long TIeff). J. Magn. Reson. Imaging 2001;14:771–778. © 2001 Wiley‐Liss, Inc.
Perfusion abnormalities in pulmonary embolism studied with perfusion MRI and ventilation‐perfusion scintigraphy: An intra‐modality and inter‐modality agreement study
Authors: Amundsen Tore , Torheim Geir , Kvistad Kjell A. , Waage Anders , Bjermer Leif , Nordlid Knut K. , Johnsen Harald , Åsberg Arne , Haraldseth Olav 
Published: August 2002

AbstractPurposeTo compare perfusion magnetic resonance imaging (MRI) and ventilation‐perfusion scintigraphy (V‐P scan) in the study of perfusion abnormalities in pulmonary embolism (PE) and to compare the PE results to the findings previously reported for pneumonia and chronic obstructive pulmonary disease (COPD), in terms of perfusion abnormalities.Materials and MethodsDynamic contrast‐enhanced MR images and V‐P scans of 20 patients with PE, 11 patients with acute pneumonia, and 13 patients with exacerbation of COPD were studied. Five categories of perfusion abnormalities within each imaging modality were defined. Intra‐ and inter‐modality agreement (kappa values) in the evaluation of perfusion abnormalities were calculated, based on the two observers of each imaging modality (all blinded to each other and true diagnosis). Finally, three categories of perfusion MRI diagnosis (PE, pneumonia, and COPD) were also defined and the inter‐observer agreement (kappa value) was calculated.ResultsFor PE, the intra‐modality agreement (kappa value) in the evaluation of perfusion abnormalities was 0.77 for MRI and 0.65 for V‐P scan. The inter‐modality agreement varied from 0.52 to 0.57, respectively, and was observer‐dependent. For the pooled group of PE, pneumonia, and COPD, the intra‐modality agreement of perfusion abnormalities was 0.76 for MRI and 0.65 for V‐P scan, and the inter‐modality agreement varied from 0.51 to 0.56. The kappa value for inter‐observer agreement for MRI diagnosis was 0.92.ConclusionEvaluation of perfusion abnormalities in PE, pneumonia, and COPD using perfusion MRI and V‐P scan showed a high intra‐modality agreement that was higher than the inter‐modality agreement. Further studies are now needed in patients presenting with possible PE to evaluate the sensitivity and specificity of the method. J. Magn. Reson. Imaging 2002;15:386–394. © 2002 Wiley‐Liss, Inc.
The effects of 1.5T magnetic resonance imaging on early murine in‐vitro embryo development
Authors: Chew Stephen , Ahmadi Ali , Goh P.S. , Foong L.C. 
Published: August 2002

AbstractAlthough no ionizing radiation is involved, patients undergoing magnetic resonance imaging (MRI) are exposed to powerful static magnetic fields, magnetic field gradients, and radio‐frequency fields that may be potentially damaging. Our study aims to document the effect of MRI imaging sequences on early murine embryo development (two‐cell to blastocyst stage) in vitro. Two‐cell murine embryos were exposed to various lengths of MRI using pulse sequences employed in present day clinical imaging. Early murine embryo development was documented in vitro, and blastocyst development rates were computed for both the control and exposed groups. There were no significant differences detected in the rate of blastocyst formation between the control groups and the embryos exposed to MRI. J. Magn. Reson. Imaging 2001;13:417–420. © 2001 Wiley‐Liss, Inc.
Freehand iMRI‐guided large‐gauge core needle biopsy: A new minimally invasive technique for diagnosis of enhancing breast lesions
Authors: Daniel Bruce L. , Birdwell Robyn L. , Butts Kim , Nowels Kent W. , Ikeda Debra M. , Heiss Steven G. , Cooper Claudia R. , Jeffrey Stefanie S. , Dirbas Frederick M. , Herfkens Robert J. 
Published: August 2002

AbstractThe lack of reliable methods for minimally invasive biopsy of suspicious enhancing breast lesions has hindered the utilization of contrast‐enhanced magnetic resonance imaging (MRI) for the detection and diagnosis of breast cancer. In this study, a freehand method was developed for large‐gauge core needle biopsy (LCNB) guided by intraprocedural MRI (iMRI). Twenty‐seven lesions in nineteen patients were biopsied using iMRI‐guided LCNB without significant complications. Diagnostic tissue was obtained in all cases. Nineteen of the 27 lesions were subsequently surgically excised. Histopathologic analysis confirmed that iMRI‐guided LCNB correctly distinguished benign lesions from malignancy in 18 of the 19 lesions. The histology revealed by core biopsy was partially discrepant with surgical biopsy in 2 of the other 19 lesions. Freehand iMRI‐guided LCNB of enhancing breast lesions is promising. Larger studies are needed to determine the smallest lesion that can be sampled reliably and to precisely measure the accuracy of iMRI‐guided LCNB as a minimally invasive tool to diagnose suspicious lesions found by breast MRI. J. Magn. Reson. Imaging 2001;13:896–902. © 2001 Wiley‐Liss, Inc.
Time course of arterial hyperintensity with fast fluid‐attenuated inversion‐recovery imaging in acute and subacute middle cerebral arterial infarction
Authors: Maeda Masayuki , Koshimoto Yoshio , Uematsu Hidemasa , Yamada Hiroki , Kimura Hirohiko , Kawamura Yasutaka , Itoh Harumi , Sakuma Hajime , Takeda Kan 
Published: August 2002

AbstractThe purpose of this study was to evaluate the time course of arterial hyperintensity (AH) in acute and subacute cerebral infarctions of the middle cerebral artery (MCA) distribution by using fast fluid‐attenuated inversion‐recovery (FLAIR) imaging. A total of 40 FLAIR MR examinations were performed in 27 patients with MCA infarction within 13 days after ictus. Thirteen patients underwent two MR examinations during this period. Thrombotic or embolic infarctions were included in this study, but lacunar infarctions were excluded. The presence or absence of AH and the location of AH were analyzed. Overall, AH was found in 24 (60%) of 40 FLAIR examinations within 13 days after onset. AH was seen in 17 (100%) examinations less than 24 hours old, four (40%) of 10 examinations 1–4 days old, two (18%) of 11 examinations 5–9 days old, and one (50%) of two examinations 10–13 days old. AH was most frequently found at the sylvian fissure (87%), followed by the sulci (54%), and the horizontal segment of MCA (29%) in the affected MCA distribution. Although AH could be seen even at 13 days after ictus, the presence of AH declined over time. AH represented an early sign of acute embolic or thrombotic infarction. J. Magn. Reson. Imaging 2001;13:987–990. © 2001 Wiley‐Liss, Inc.
Oblique sagittal view of the anterior cruciate ligament: Comparison of coronal vs. axial planes as localizing sequences
Authors: Barberie John E. , Carson Brent W. , Finnegan Martin , Wong Anthony D. 
Published: August 2002

AbstractThe purpose of this study was to determine whether oblique sagittal T2‐weighted images of the anterior cruciate ligament (ACL) are better prescribed off axial or coronal localizing images. Thirty‐one patients underwent two sets of oblique sagittal T2‐weighted fast spin‐echo sequences to evaluate the ACL. One oblique was prescribed from a coronal localizing sequence, while the other was prescribed off an axial series. Objective (average number of images to demonstrate ACL) and subjective (radiologist's confidence level) evaluations of both sequences were performed independently of the other and then comparatively by two radiologists. The coronally prescribed sagittal oblique was subjectively preferred in 18 patients, the axially prescribed oblique was preferred in one patient, and both sequences were felt to be equivalent in 12 patients. In 13 intact ligaments, the average number of images clearly demonstrating the entire length of the ACL was 1.77 on the coronally prescribed sequence and 1.31 on the axially prescribed images. Oblique sagittal images prescribed off a coronal localizer are both subjectively and objectively more effective than axially prescribed sagittal obliques in evaluating the ACL. J. Magn. Reson. Imaging 2001;14:203–206. © 2001 Wiley‐Liss, Inc.