bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute downregulation of Cx43 alters P2Y receptor expression levels in mouse spinal cord astrocytes
Authors: Suadicani Sylvia O. , De Pina‐Benabou Mara Helena , Urban‐Maldonado Marcia , Spray David C. , Scemes Eliana
Published: March 2003

Propagation of intercellular calcium waves (ICW) between astrocytes depends on the diffusion of signaling molecules through gap junction channels and diffusion through the extracellular space of neuroactive substances acting on plasmalemmal receptors. The relative contributions of these two pathways vary in different brain regions and under certain pathological conditions. We have previously shown that in wild‐type spinal cord astrocytes, ICW are primarily gap junction‐dependent, but that deletion of the main gap junction protein (Cx43) by homologous recombination results in a switch in mode of ICW propagation to a purinoceptor‐dependent mechanism. Such a compensatory mechanism for ICW propagation was related to changes in the pharmacological profile of P2Y receptors, from an adenine‐sensitive P2Y1, in wild‐type, to a uridine‐sensitive P2U receptor subtype, in Cx43 knockout (KO) astrocytes. Using oligonucleotide antisense to Cx43 mRNA for acute downregulation of connexin43 expression levels, we provide evidence for the molecular nature of such compensatory mechanism. Pharmacological studies and Western blot analysis indicate that there is a reciprocal regulation of P2Y1 and P2Y4 expression levels, such that downregulation of Cx43 leads to decreased expression of the adenine‐sensitive P2Y1 receptor and increased expression of the uridine‐sensitive P2Y4 receptor. This change in functional expression of the P2Y receptor subtype population in acutely downregulated Cx43 was paralleled by changes in the mode of ICW propagation, similar to that previously observed for Cx43 KO spinal cord astrocytes. On the basis of these results, we propose that Cx43 regulates both modes of ICW by altering P2Y receptor subtype expression in addition to providing intercellular coupling. GLIA 42:160–171, 2003. © 2003 Wiley‐Liss, Inc.
Temporal progressive antigen expression in radial glia after contusive spinal cord injury in adult rats
Authors: Shibuya Sei , Miyamoto Osamu , Itano Toshifumi , Mori Satoshi , Norimatsu Hiromichi
Published: March 2003

In the development of the CNS, radial glial cells are among the first cells derived from neuroepithelial cells. Recent studies have reported that radial glia possess properties of neural stem cells. We analyzed the antigen expression and distribution of radial glia after spinal cord injury (SCI). Sprague‐Dawley rats had a laminectomy at Th11‐12, and spinal cord contusion was created by compression with 30g of force for 10 min. In the injury group, rats were examined at 24 h and 1, 4, and 12 weeks after injury. Frozen sections of 20‐μm thickness were prepared from regions 5 and 10 mm rostral and caudal to the injury epicenter. Immunohistochemical staining was performed using antibodies to 3CB2 (a specific marker for radial glia), nestin, and glial fibrillary acidic protein (GFAP). At 1 week after injury, radial glia that bound anti‐3CB2 MAb had spread throughout the white matter from below the pial surface. From 4 weeks after injury, 3CB2 expression was also observed in the gray matter around the central canal, and was especially strong around the ependymal cells and around blood vessels. In double‐immunohistochemical assays for 3CB2 and GFAP or 3CB2 and nestin, coexpression was observed in subpial structures that extended into the white matter as arborizing processes and around blood vessels in the gray matter. The present study demonstrated the emergence of radial glia after SCI in adult mammals. Radial glia derived from subpial astrocytes most likely play an important role in neural repair and regeneration after SCI. GLIA 42:172–183, 2003. © 2003 Wiley‐Liss, Inc.
Slit and glypican‐1 mRNAs are coexpressed in the reactive astrocytes of the injured adult brain
Authors: Hagino Seita , Iseki Ken , Mori Tetsuji , Zhang Yuxiang , Hikake Tsuyoshi , Yokoya Sachihiko , Takeuchi Mayumi , Hasimoto Hiromi , Kikuchi Shinichi , Wanaka Akio
Published: March 2003

The slit family serves as a repellent for growing axons toward correct targets during neural development. A recent report describes slit mRNAs expressed in various brain regions in adult rats. However, their functions in the adult nervous system remain unknown. In the present study, we investigated whether slit mRNAs were expressed in the cryo‐injured brain, using in situ hybridization. All slit family members were expressed at the lesion. Slit2 mRNA was the most intensely expressed in the cells surrounding the necrotic tissue. A double‐labeling study showed that slit2 mRNA was expressed in the glial fibrillary acidic protein (GFAP)‐positive reactive astrocytes. In addition, glypican‐1, a heparan sulfate proteoglycan that serves as a high‐affinity receptor for Slit protein, was coexpressed with slit2 mRNA in the reactive astrocytes. These findings suggested that slit2 might prevent regenerating axons from entering into the lesion in concert with glypican‐1. GLIA 42:130–138, 2003. © 2003 Wiley‐Liss, Inc.
Identification of differentially expressed proteins in human glioblastoma cell lines and tumors
Authors: Zhang Rulin , Tremblay Tammy‐Lynn , Mcdermid Angela , Thibault Pierre , Stanimirovic Danica
Published: March 2003

An in‐frame deletion of 801 bp in exons 2–7 (type III mutation) of the epidermal growth factor receptor (EGFR) is detected at high incidence in primary glioblastoma tumors. A proteomic approach was used to generate differential protein expression maps of fetal human astrocytes (FHA), human glioblastoma cell lines U87MG and U87MG expressing type III EGFR deletion (U87MGΔEGFR) that confers high malignancy to tumor cells. Two‐dimensional gel electrophoresis followed by in‐gel digestion of separated spots and protein identification by LC‐MS‐MS and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) identified 23 proteins expressed at higher levels or exclusively in FHA and 29 proteins expressed at higher levels or exclusively in U87MG cells. Three proteins, ubiquitin, cystatin B, and tissue transglutaminase (TTG), were upregulated in U87MGΔEGFR relative to U87MG. Four proteins highly expressed by U87MG cells, Hsp27, major vault protein, TTG, and cystatin B, were analyzed by Western blot, ELISA, or RT‐PCR in cell extracts and in tissue samples of glioblastoma multiforme (GBM; grade IV), low‐grade astrocytomas (grades I and II), and nonmalignant brain lesions. All four proteins were highly expressed in GBM tissues compared to nonmalignant brain. These proteins may be used as diagnostic or functional (e.g., multiple drug resistance, invasiveness) markers for glioblastoma tumors. GLIA 42:194–208, 2003. © 2003 Wiley‐Liss, Inc.
Active Src expression is induced after rat peripheral nerve injury
Authors: Zhao Ying‐Luan , Takagawa Kiyoshi , Oya Takeshi , Yang Hong‐Fa , Gao Zhi‐Yang , Kawaguchi Makoto , Ishii Yoko , Sasaoka Toshiyasu , Owada Koji , Furuta Isao , Sasahara Masakiyo
Published: March 2003

The non–receptor‐type Src tyrosine kinases are key components of intracellular signal transduction that are expressed at high levels in the nervous system. To improve understanding of the cascades of molecular events underlying peripheral nerve regeneration, we analyzed active Src expression in the crushed or cut rat sciatic nerves using a monoclonal antibody (clone 28) that recognizes the active form of Src tyrosine kinases, including c‐Src and c‐Fyn. Western blots showed that active Src expressed in the normal sciatic nerve transiently increased up to threefolds after both types of injury. Immunohistochemistry using clone 28 showed that axonal components are the primary sites of active Src expression in the normal sciatic nerve. Soon after both types of injury, active Src was abundantly expressed in Schwann cells of the segments distal to the injury site. The expression of active Src in the cells decreased with restoration of the axon‐Schwann cell relationship and eventually became depleted to very low levels after crushing, but was sustained at high levels in the cut model until the end of the experiment. Regenerated axons consistently expressed active Src throughout nerve regeneration and these eventually became the major sites of active Src expression in the crushed nerve. Among the Src tyrosine kinases, active c‐Src selectively increased after crushing according to immunoprecipitation and immunoblotting analyses. Due to its potent biological activity, the increased amounts of the active form of Src probably enhance axonal regrowth, the Schwann cell response, and axon‐Schwann cell contact for peripheral nerve regeneration. GLIA 42:184–193, 2003. © 2003 Wiley‐Liss, Inc.
On the ontogeny of Leptodora kindtii (Crustacea, Branchiopoda, Cladocera), with notes on the phylogeny of the Cladocera
Authors: Olesen Jørgen , Richter Stefan , Scholtz Gerhard
Published: March 2003

Leptodora kindtii, a large predaceous cladoceran, is among the most deviant species of the Cladocera. Therefore, its phylogenetic position has traditionally proven difficult to determine. Its many peculiar features include, among others, long, stenopodous, forwardly directed trunk limbs, a posteriorly placed dorsal brood pouch, a tri‐lobed lower lip, and a long, segmented abdomen. This study describes the ontogeny of L. kindtii (Haplopoda), including general body proportions, appendages, the carapace, and other external structures in an attempt to facilitate the comparison of its aberrant morphology to that of other branchiopods. In general, the early embryos are similar to the early embryos of other cladoceran taxa with respect to body shape and size and position and orientation of the early limb buds. Many of the unusual features of L. kindtii appear late in ontogeny. The carapace appears at an early stage as a pair of dorsolateral swellings in a position corresponding to the gap between the mandibles and the first pair of trunk limbs; it later becomes posteriorly transposed by a gradual fusion of its more anterior parts to the dorsal side of the thorax. The tri‐lobed “lower lip,” under the labrum of the late embryo and the adult, develops as a fusion of the first maxillae (lateral lobes) to an elevated sternal region behind the mouth (median lobe). The stenopodous, segmented trunk limbs in the adult develop from embryonic, elongate, subdivided limb buds, similar to those seen in early stages of other branchiopods. Two conflicting possibilities for the phylogeny of the Cladocera, involving two different positions of L. kindtii (Haplopoda), are discussed. Several characters support a sister‐group relationship between the Haplopoda and Onychopoda. However, some characters support the Anomopoda and Onychopoda as sister groups, leaving the Haplopoda outside this clade. In contrast to recent suggestions, we prefer to retain the term “Cladocera” in its original sense as comprising the Haplopoda, Ctenopoda, Anomopoda, and Onychopoda. J. Morphol. 256:235–259, 2003. © 2003 Wiley‐Liss, Inc.
Craniofacial variation of the Chinese macaques explored with Morphologika
Authors: Pan Ruliang , Wei Fuwen , Li Ming
Published: March 2003

In order to analyze, separately and dynamically, the variation in cranial size and shape of Chinese macaques, a new method, Morphologika, was used to illustrate 3D profiles based on the coordinates of 26 landmarks on the skull. Striking image variation between the two sexes was detected on the facial region: males exhibited a larger and more protrusive facial structure. Males also displayed a bigger cranium than females. The two sexes also showed quite different images in skull shape. However, they expressed the same allometric pattern with regard to the relationship between size and shape, which was significantly positively associated with each other along the first axis. The same relationship was negatively displayed along the second axis when the two sexes were analyzed together. However, only the relationship for females reached a significant level when the two sexes were studied separately. This was considered to be related to their differentiation in growth trajectory. This study also tested the concept of size revealed by the second axis of principal components analysis based on traditional morphometric methods on the same taxa. J. Morphol. 256:342–348, 2003. © 2003 Wiley‐Liss, Inc.
Surface glycoconjugates in the olfactory system of Ambystoma mexicanum
Authors: Franceschini Valeria , Lazzari Maurizio , Ciani Franco
Published: March 2003

Lectin binding histochemistry was performed on the olfactory system of neotenic and metamorphosed Ambystoma mexicanum to investigate the distribution and density of defined carbohydrate residues on the cell surface glycoproteins of the olfactory and vomeronasal receptor cells and their terminals in the olfactory bulbs. The lectin binding patterns indicate that the main olfactory system possesses a high density of N‐acetyl‐galactosamine and N‐acetyl‐glucosamine residues, while the vomeronasal system contains a high density of N‐acetyl‐galactosamine and galactose moieties and a moderate density of N‐acetyl‐glucosamine. The presence of specific glycoproteins, whose terminal sugars are detected by lectin binding, might be related to the chemoreception and transduction of the odorous message into a nervous signal or to the histogenesis and development of the olfactory system. In fact, the olfactory and vomeronasal receptor cells are neurons that undergo a continuous cycle of proliferation not only during development but also in mature animals. J. Morphol. 256:301–305, 2003. © 2003 Wiley‐Liss, Inc.
Comparison of testes structure, spermatogenesis, and spermatocytogenesis in young, aging, and hybrid cichlid fish (Cichlidae, Teleostei)
Authors: Fishelson Lev
Published: March 2003

Testis structure, spermatogenesis, and spermatocytogenesis were compared in 13 species of cichlid fishes, belonging to the subfamilies Haplochrominae and Tilapinae. The species studied were either mouth brooders, in which fertilization occurs mostly inside the mouth of the brooding fish, or substrate brooders, whose eggs adhere to a substrate over which the sperm is ejaculated. In this study, the embryogenesis of testes anlagen and sperm production was followed in embryos and in fish up to 15 years old, as well as in hybrids of the two subfamilies. In cichlids, the testes are of the unrestricted type and primary spermatogonia develop along the entire length of the developing sperm tubule. The first primary spermatogonia are observed in the testes anlagen 2–5 days after fertilization and they continue to develop in cysts formed by the enveloping Sertoli cells and the intertubular elements. The dimensions of such primary and secondary spermatocysts are correlated with the number of spermatogonia they contain and the corresponding number of mitotic multiplications. The largest mature cysts attained 300 μm, and contained 2,200–2,400 spermatids in the mouth‐brooding species and 2,600–3,200 in the substrate‐brooding species. Despite the fact that in such cysts cytoplasmic bridges connect only the isogamete spermatids, the maturation of all cells and consequent spermiation is synchronized. Meristic characters distinguish the sperm of mouth brooders from those of substrate brooders, especially in the number of mitochondria and length of the flagellum. In older fish and hybrids, various changes can be seen in the gametogenic epithelium and intertubular cells. These include thickening of the connective tissue, formation of “yellow” groups of Leydig cells, cell apoptosis and degeneration, and, especially, formation of large spermatogonia, with large, electron‐dense nucleoli, that have the cytological characteristics of oocytes. The intra‐ and interspecific variability of sperm dimensions in the studied cichlids poses an interesting question in the context of sperm competition. J. Morphol. 256:285–300, 2003. © 2003 Wiley‐Liss, Inc.
Altered histology of the thymus and spleen in contaminant‐exposed juvenile American alligators
Authors: Rooney Andrew A. , Bermudez Dieldrich S. , Guillette Louis J.
Published: March 2003

Morphological differences in spleen and thymus are closely related to functional immune differences. Hormonal regulation of the immune system has been demonstrated in reptilian splenic and thymic tissue. Spleens and thymus were obtained from juvenile alligators at two reference sites in Florida, USA: Orange Lake and a National Wildlife Refuge, Lake Woodruff, as well as from a contaminated lake, Lake Apopka. Lake Apopka has been extensively polluted with agricultural pesticides. Tissues were prepared for histological analysis to determine if previously detected endocrine abnormalities associated with contaminant exposure might also be reflected in morphological differences in splenic and thymic structures important for immunological response. Similar tissues were taken from captive‐raised juvenile female alligators (3 years old) that were hatched from eggs collected on Lake Woodruff and Lake Apopka. Differences in thymic ratios (medulla/cortex) were found among alligators collected from the two lakes (P = 0.0051). Alligators from Lake Apopka had smaller thymic ratios than animals from either reference lake. Males from Lake Woodruff had significantly smaller lymphocyte sheaths in the spleen than females (P = 0.0009), indicative of a normal sexual dimorphism. Lymphocyte sheath width differed among females obtained from the three lakes, with females from Lake Apopka having the smallest sheath width and those from Orange Lake having the largest. Malpighian body area was largest in alligators from Orange Lake, intermediate in Lake Woodruff, and smallest in Lake Apopka. In contrast to that observed for wild‐caught animals, no difference was found in the thymic medulla/cortex ratio of captive‐raised female alligators (P = 0.378). Captive‐raised female alligators from Lake Apopka and Lake Woodruff displayed lake‐associated differences in lymphocyte sheath width as observed in wild animals; Lake Apopka alligators had smaller lymphocyte sheath width compared to Woodruff alligators (P = 0.0396). In contrast to wild‐caught animals, area of the Malpighian bodies did not differ by lake in the captive‐raised female alligators (P = 0.066). The enlarged thymic cortex suggests a change in T‐lymphocyte maturation within the thymus of alligators from a contaminated environment, Lake Apopka. The results point to alterations in the histology of the thymus and spleen. Further studies are required to examine the functional significance of these observations. J. Morphol. 256:349–359, 2003. © 2003 Wiley‐Liss, Inc.
Postcanine dental form in the mustelidae and viverridae (Carnivora: Mammalia)
Authors: Popowics Tracy E.
Published: March 2003

This study investigates whether the gross morphology of mustelid and viverrid postcanine dentitions corresponds with differences in diet. For each species, the predominant foods ingested are used to form predictions of dental form and measurements of the carnassial and molar teeth determine the extent of shearing and crushing surfaces on the postcanine teeth. Principal components analysis distinguishes species according to morphological differences in the dentition and these differences are compared with predictions of dental form based on diet. Dietarily specialized species are more likely to be correspondingly specialized in the dentition and species with varied food sources are more likely to possess dental characteristics that are generalized in function. Consumers of foods with high fracture resistance, such as vertebrate tissue and hard‐surfaced invertebrates, possess specialized shearing or crushing postcanine teeth. On the other hand, species that consume foods of lesser fracture resistance, such as fruit and soft invertebrates, differ greatly in dental form and are more generalized in dental function. A few species possess postcanine dentitions that do not correspond with diet; the absence of dental–dietary correlation in these species suggests that other factors, such as phylogeny, are important in determining dental form. J. Morphol. 256:322–341, 2003. © 2003 Wiley‐Liss, Inc.
Formation of the arthrodial membrane in the blue crab, Callinectes sapidus
Authors: Williams C.L. , Dillaman R.M. , Elliott E.A. , Gay D.M.
Published: March 2003

In this study the pattern of arthrodial membrane deposition in Callinectes sapidus was determined by histological and ultrastructural examination of tissues from the carpus joint of the cheliped collected during premolt, ecdysis, postmolt, and intermolt. Apolysis in the arthrodial membrane occurs at stage D0 and is synchronous with apolysis of the calcified cuticle. Epicuticle formation begins at early stage D1 and is completed in late stage D1. Procuticle deposition starts at D2 and continues until ecdysis. Numerous cytoplasmic extensions occur throughout the lamellae. Component fibers of the arthrodial membrane are intimately associated with dense plaques on the apical membrane of the underlying hypodermal cells, suggesting a site for fiber polymerization. Deposition of the arthrodial membrane continues after ecdysis, with most of the cuticle thickening occurring during stage C. When stained with PAS and counterstained with hematoxylin, a difference can be discerned between preecdysial and postecdysial procuticle of the arthrodial membrane, a distinction not made in previous studies. The boundary between the arthrodial membrane and calcified cuticle is thicker than either of the two layers and the layers overlap rather than butting up against one another. This pattern suggests that underlying hypodermal cells have to produce multiple types of cuticle over the molt cycle. A summary of the various molting patterns in C. sapidus suggests that the control of these diverse events may prove to be complex. J. Morphol. 256:260–269, 2003. © 2003 Wiley‐Liss, Inc.
Functional morphology of prey capture in the sturgeon, Scaphirhynchus albus
Authors: Carroll Andrew M. , Wainwright Peter C.
Published: March 2003

Acipenseriformes (sturgeon and paddlefish) are basal actinopterygians with a highly derived cranial morphology that is characterized by an anatomical independence of the jaws from the neurocranium. We examined the morphological and kinematic basis of prey capture in the Acipenseriform fish Scaphirhynchus albus, the pallid sturgeon. Feeding pallid sturgeon were filmed in lateral and ventral views and movement of cranial elements was measured from video sequences. Sturgeon feed by creating an anterior to posterior wave of cranial expansion resulting in prey movement through the mouth. The kinematics of S. albus resemble those of other aquatic vertebrates: maximum hyoid depression follows maximum gape by an average of 15 ms and maximum opercular abduction follows maximum hyoid depression by an average of 57 ms. Neurocranial rotation was not a part of prey capture kinematics in S. albus, but was observed in another sturgeon species, Acipenser medirostris. Acipenseriformes have a novel jaw protrusion mechanism, which converts rostral rotation of the hyomandibula into ventral protrusion of the jaw joint. The relationship between jaw protrusion and jaw opening in sturgeon typically resembles that of elasmobranchs, with peak upper jaw protrusion occurring after peak gape. J. Morphol. 256:270–284, 2003. © 2003 Wiley‐Liss, Inc.
Ultrastructural and ultracytochemical study of the middle ear epithelium in the chicken, Gallus gallus domesticus
Authors: Giannessi Francesco , Giambelluca Maria A. , Scavuzzo Maria C. , Fattori Bruno , Ruffoli Riccardo
Published: March 2003

The fine structure of the epithelium lining the tympanic cavity of the chicken was studied by TEM and SEM. In addition, the distribution of nonspecific esterase activity in the epithelium was investigated by TEM. Ultrastructural study revealed the presence of disk‐like apical protrusions of the epithelial cells, previously not observed in other cell types. The protrusions contained some cytoplasmic organelles and were characterized by a ring‐shaped thickening around their periphery. The ring was made up of a granulo‐filamentous material. Our observations clearly indicate the existence of an apocrine secretory mechanism, consisting of a progressive detachment of disk‐like protrusions from the apex of the epithelial cells. The ultracytochemical study demonstrated nonspecific esterase activity on the epithelial surface and in the secretory vesicles. We propose that nonspecific esterase is a marker for middle ear surfactant in birds. J. Morphol. 256:371–378, 2003. © 2003 Wiley‐Liss, Inc.
MRI tissue characterization of experimental cerebral ischemia in rat
Authors: Soltanian‐Zadeh Hamid , Pasnoor Mamatha , Hammoud Rabih , Jacobs Michael A. , Patel Suresh C. , Mitsias Panayiotis D. , Knight Robert A. , Zheng Zhang G. , Lu Mei , Chopp Michael
Published: March 2003

Purpose

To extend the ISODATA image segmentation method to characterize tissue damage in stroke, by generating an MRI score for each tissue that corresponds to its histological damage.

Materials and Methods

After preprocessing and segmentation (using ISODATA clustering), the proposed method scores tissue regions between 1 and 100. Score 1 is assigned to normal brain matter (white or gray matter), and score 100 to cerebrospinal fluid (CSF). Lesion zones are assigned a score based on their relative levels of similarities to normal brain matter and CSF. To evaluate the method, 15 rats were imaged by a 7T MRI system at one of three time points (acute, subacute, chronic) after MCA occlusion. Then they were killed and their brains were sliced and prepared for histological studies. MRI of two or three slices of each rat brain (using two DWI (b = 400, b = 800), one PDWI, one T2WI, and one T1WI) was performed, and an MRI score between 1 and 100 was determined for each region. Segmented regions were mapped onto the histology images and scored on a scale of 1–10 by an experienced pathologist. The MRI scores were validated by comparison with histology scores. To this end, correlation coefficients between the two scores (MRI and histology) were determined.

Results

Experimental results showed excellent correlations between MRI and histology scores at different time points. Depending on the reference tissue (gray matter or white matter) used in the standardization, the correlation coefficients ranged from 0.73 (P < 0.0001) to 0.78 (P < 0.0001) using the entire dataset, including acute, subacute, and chronic time points. This suggests that the proposed multiparametric approach accurately identified and characterized ischemic tissue in a rat model of cerebral ischemia at different stages of stroke evolution.

Conclusion

The proposed approach scores tissue regions and characterizes them using unsupervised clustering and multiparametric image analysis techniques. The method can be used for a variety of applications in the field of computer‐aided diagnosis and treatment, including evaluation of response to treatment. For example, volume changes for different zones of the lesion over time (e.g., tissue recovery) can be evaluated. J. Magn. Reson. Imaging 2003;17:398–409. © 2003 Wiley‐Liss, Inc.
Dynamic MRI of breast hardness following radiation treatment
Authors: Padhani Anwar R. , Yarnold John , Regan Jane , Husband Janet E.
Published: March 2003

Purpose

To evaluate functional microvascular characteristics of breast induration several years after radiation treatment using dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) techniques.

Materials and Methods

Fifteen women with moderate or marked breast induration after surgery and radiotherapy for breast cancer (2–15 years) were examined. Images of the irradiated breast (boost and nonboost sites) on short tau inversion recovery (STIR) and DCE‐MRI sequences were subjectively evaluated for edema and the presence of enhancement and compared to the contralateral normal breast. Quantitative enhancement parameters—percent enhancing pixels, transfer constant (Ktrans), rate constant (kep), leakage space (ve), and maximum contrast medium accumulation (MCMA)—were also compared.

Results

No tumor recurrence was seen. Fat necrosis was seen in 2/15 cases. Increased parenchymal edema at the electron boost site was seen in 12/14 patients. Greater enhancement in the irradiated breast was seen in 11/14 evaluable patients. Kinetic parameter estimates including Ktrans were similar except for percent enhancing pixels, which was greater in the irradiated breast at both boost and nonboost sites (P = 0.03 and 0.04, respectively). ve and MCMA estimates were greater in breasts with marked induration compared to moderate grades (P = 0.002 and 0.01, respectively).

Conclusion

Parenchymal edema may be an important contributor to palpable induration several years after breast radiotherapy. Increased fluid content may be related to increased numbers of perfused microvessels and/or impaired lymphatic drainage. J. Magn. Reson. Imaging 2003;17:427–434. © 2003 Wiley‐Liss, Inc.
In vivo accuracy of multisequence MR imaging for identifying unstable fibrous caps in advanced human carotid plaques
Authors: Mitsumori Lee M. , Hatsukami Thomas S. , Ferguson Marina S. , Kerwin William S. , Cai Jianming , Yuan Chun
Published: March 2003

Purpose

To evaluate the in vivo accuracy of a multisequence MRI technique for prospectively identifying one feature of the vulnerable plaque—an unstable fibrous cap—in human carotid atherosclerosis.

Materials and Methods

The carotid arteries of 18 endarterectomy patients were preoperatively imaged in a 1.5T scanner using a multisequence protocol that generated four contrast weightings (3D time of flight (ToF), T1, proton density (PD), and T2) at each slice location. With the use of previously published MR criteria, the images of the vessel wall were first examined for evidence of an unstable fibrous cap. The imaging findings were then correlated with the histology from the surgical specimens.

Results

A blinded review of the MR findings with the histologic state of the fibrous cap revealed that 1) assessing the preoperative appearance of the fibrous cap has a high test sensitivity (0.81) and specificity (0.90) for identifying an unstable cap in vivo; and 2) the availability of different contrast weightings facilitated image interpretation when intimal calcifications or flow artifacts obscured the lumen surface.

Conclusion

Multisequence MRI can accurately characterize the in vivo state of the fibrous cap. This finding supports the use of these noninvasive techniques to prospectively identify vulnerable plaques. J. Magn. Reson. Imaging 2003;17:410–420. Published 2003 Wiley‐Liss, Inc.
Calibrated magnetic resonance hydrometry: An in vitro study
Authors: Heverhagen Johannes T. , Boehm Dominik , Klose Klaus J.
Published: March 2003

Purpose

To demonstrate a quantitative approach to measuring fluid volumes with standard single shot RARE sequences.

Materials and Methods

In phantom experiments, magnetic resonance hydrometry (MRH), in combination with various calibration phantoms (5 mL up to 500 mL) as internal standards, was used to quantify fluid volumes. In total, 16 volume phantoms were investigated with six different calibration phantoms. In addition, noise correction was implemented to correct the quantification results and to avoid the influence of random noise in the image.

Results

All MR measurements show significant correlations of up to r = 0.99 (P < .05) with the real applied volume in the investigated phantoms. However, measurements of large volumes were more precise with large calibration phantoms. Noise reduction did not change the correlation between measured and real applied volumes, but did reduce the error of the measured volumes. Calibrated magnetic resonance hydrometry (cMRH) is able to quantify volumes of fluid fast and noninvasively. The volumes of the used calibration phantoms have to be at least in the order of magnitude of the volumes that are to be measured.

Conclusion

In vitro, cMRH using a single‐shot rapid acquisition with refocused echoes (ssRARE) sequence and calibration phantoms is a fast and accurate method of quantifying steady amounts of fluid. J. Magn. Reson. Imaging 2003;17:472–477. © 2003 Wiley‐Liss, Inc.
Time‐resolved three‐dimensional phase‐contrast MRI
Authors: Markl Michael , Chan Frandics P. , Alley Marcus T. , Wedding Kris L. , Draney Mary T. , Elkins Chris J. , Parker David W. , Wicker Ryan , Taylor Charles A. , Herfkens Robert J. , Pelc Norbert J.
Published: March 2003

Purpose

To demonstrate the feasibility of a four‐dimensional phase contrast (PC) technique that permits spatial and temporal coverage of an entire three‐dimensional volume, to quantitatively validate its accuracy against an established time resolved two‐dimensional PC technique to explore advantages of the approach with regard to the four‐dimensional nature of the data.

Materials and Methods

Time‐resolved, three‐dimensional anatomical images were generated simultaneously with registered three‐directional velocity vector fields. Improvements compared to prior methods include retrospectively gated and respiratory compensated image acquisition, interleaved flow encoding with freely selectable velocity encoding (venc) along each spatial direction, and flexible trade‐off between temporal resolution and total acquisition time.

Results

The implementation was validated against established two‐dimensional PC techniques using a well‐defined phantom, and successfully applied in volunteer and patient examinations. Human studies were performed after contrast administration in order to compensate for loss of in‐flow enhancement in the four‐dimensional approach.

Conclusion

Advantages of the four‐dimensional approach include the complete spatial and temporal coverage of the cardiovascular region of interest and the ability to obtain high spatial resolution in all three dimensions with higher signal‐to‐noise ratio compared to two‐dimensional methods at the same resolution. In addition, the four‐dimensional nature of the data offers a variety of image processing options, such as magnitude and velocity multi‐planar reformation, three‐directional vector field plots, and velocity profiles mapped onto selected planes of interest. J. Magn. Reson. Imaging 2003;17:499–506. © 2003 Wiley‐Liss, Inc.
Flow‐independent magnetic resonance venography of the calf
Authors: Gallix Benoît P. , Achard‐Lichère Cécile , Dauzat Michel , Bruel Jean‐Michel , Lopez Francois‐Michel
Published: March 2003

Purpose

To show that flow‐independent venography that exploit the intrinsic MR properties of blood to isolate vessels from surrounding structures can be used for depiction of peripheral veins and for detection of deep venous thrombosis (DVT).

Materials and Methods

Sequence and parameters were first determined on a theoretical basis. The sequence was then optimized in volunteers (N = 4) for the depiction of the peripheral venous vessels. Qualitative evaluation of the normal venous anatomy was performed in five volunteers. The feasibility of diagnosing DVT of the calf with this method was evaluated with preliminary clinical studies.

Results

Excellent depiction of the venous anatomy was achieved in all volunteers with the optimized technique. Very small venous structures, such as superficial, muscular, and perforator veins, were clearly depicted because of the high spatial and contrast resolution capacities of the sequences. In all six patients, DVT findings diagnosed by duplex sonography were also seen on MR venography.

Conclusion

Venous anatomy mapping and detection of lower‐limb DVT appear feasible using flow‐independent MR venograms. J. Magn. Reson. Imaging 2003;17:421–426. © 2003 Wiley‐Liss, Inc.
Tumor vascular architecture and function evaluated by non‐invasive susceptibility MRI methods and immunohistochemistry
Authors: Robinson Simon P. , Rijken Paul F.J.W. , Howe Franklyn A. , McSheehy Paul M.J. , van der Sanden Boudewijn P.J. , Heerschap Arend , Stubbs Marion , van der Kogel Albert J. , Griffiths John R.
Published: March 2003

Purpose

To investigate the physiological origins responsible for the varying blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) responses to carbogen (95% O2/5% CO2) breathing observed with different tumor types.

Materials and Methods

Susceptibility contrast‐enhanced MRI using the exogenous blood pool contrast agent NC100150 to determine blood volume and vessel size, and immunohistochemical‐derived morphometric parameters, were determined in GH3 prolactinomas and RIF‐1 fibrosarcomas, both grown in mice, which exhibited very different BOLD responses to carbogen.

Results

Administration of NC100150 increased the R2* and R2 rates of both tumor types, and indicated a significant four‐fold larger blood volume in the GH3 tumor. The ratio ΔR2*/ΔR2 showed that the capillaries in the GH3 were two‐fold larger than those in the RIF‐1, in agreement with morphometric analysis. Carbogen breathing induced a significant 25% decrease in R2* in the GH3 prolactinoma, whereas the response in the RIF‐1 fibrosarcoma was negligible.

Conclusion

Low blood volume and small vessel size (and hence reduced hematocrit) are two reasons for the lack of R2* change in the RIF‐1 with carbogen breathing. BOLD MRI is sensitive to erythrocyte‐perfused vessels, whereas exogenous contrast agents interrogate the total perfused vascular volume. BOLD MRI, coupled with a carbogen challenge, provides information on functional, hemodynamic tumor vasculature. J. Magn. Reson. Imaging 2003;17:445–454. © 2003 Wiley‐Liss, Inc.
Magnetic resonance microscopy quantifies the disease progression in Marfan syndrome mice
Authors: Itskovich Vitalii V. , Lieb Mark , Aguinaldo Juan Gilberto S. , Samber Daniel D. , Ramirez Francesco , Fayad Zahi A.
Published: March 2003

Purpose

To use noninvasive magnetic resonance microscopy (MRM) to examine aneurysmal disease in the mouse model of Marfan syndrome (MFS).

Materials and Methods

A total of eight wild‐type (WT) and MFS mice were imaged using MRM; four of them at three different time points over an 8‐week period and the remaining animals were imaged at one time point. The maximal cross‐sectional area of the aorta was measured by manual tracing and by automated means from combined cardiac and respiratory‐gated bright‐blood images. Relationships between aortic size and age and the differences between WT and mutant mice aortic size were established.

Results

Maximal cross‐sectional aortic areas differed significantly (P < 0.05) between WT and mutant mice for all time points, with MFS mice having larger aortic size. There was a positive correlation between aortic size and age in MFS mice (r = 0.80) with a significant increase from the 14th to the 22nd week (P < 0.05).

Conclusion

MRM detected the differences in aortic size between WT and mutant mice over time, demonstrating a potential for noninvasive technique for the assessment of potential therapies in MFS mice. J. Magn. Reson. Imaging 2003;17:435–439. © 2003 Wiley‐Liss, Inc.
Challenges in dynamic contrast‐enhanced MRI imaging of cervical lymph nodes to detect metastatic disease
Authors: Noworolski Susan M. , Fischbein Nancy J. , Kaplan Michael J. , Lu Ying , Nelson Sarah J. , Carvajal Lucas , Henry Roland G.
Published: March 2003

Purpose

To identify and overcome challenges in using dynamic contrast‐enhanced magnetic resonance imaging (MRI) to distinguish tumor from nontumor in the cervical lymph nodes of patients with squamous cell carcinoma of the head and neck.

Materials and Methods

Signal‐to‐noise ratio (S/N), motion, node heterogeneity, and tissue normalizations were examined. Twenty‐one patients with squamous cell carcinoma of the head and neck were scanned before a neck dissection (two‐dimensional fast spoiled gradient‐echo: 10 locations/13 seconds). Peak time, peak enhancement, maximum upslope, and washout slope were measured in pathologically confirmed tumor and nontumor nodes and in the submandibular gland and the sternocleidomastoid muscle.

Results

Surface coil arrays provided high coverage and high S/N. Motion averaged 1.1 pixels and was corrected. Large tumor nodes were heterogeneous in their contrast enhancement, while the nontumor nodes were homogeneous. The contrast enhancement parameters were significantly different for all regions except for the submandibular gland compared to the nontumor nodes.

Conclusion

Challenges of dynamic imaging of cervical lymph nodes were overcome and significant differences were found between the tumor and nontumor nodes, indicating that dynamic imaging is feasible and may aid this patient population. J. Magn. Reson. Imaging 2003;17:455–462. © 2003 Wiley‐Liss, Inc.
Juxtapapillary diverticulum: Findings on MRI
Authors: Balci N. Cem , Noone Tara , Akün Elif , Akinci Ahmet , Klör Hans‐Ulrich
Published: March 2003

The purpose of our study was to describe the imaging findings of juxtapapillary diverticulum on magnetic resonance imaging (MRI). The MRI and magnetic resonance cholangiopancreatography (MRCP) examinations of 14 patients with juxtapapillary diverticula that were diagnosed on endoscopic retrograde cholangiopancreatography (ERCP) (N = 8) or endoscopy (N = 6) were retrospectively evaluated. T1‐weighted spoiled gradient‐echo, T2‐weighted half Fourier single shot fast spin‐echo (HASTE), and T2‐weighted True FISP (fast imaging with steady state precession) images and thin‐slice MRCP images were obtained on all patients. In five patients, diluted gadolinium DPTA (1/100) was used as an oral contrast. T2‐weighted True FISP and HASTE images demonstrated air‐fluid levels within all diverticula. Hyperintense oral contrast on T1‐weighted spoiled gradient‐echo images aided detection of the smaller diverticula. MRCP images obtained in the coronal plane best demonstrated the relationship of the diverticula to the papilla. MRI with the use of HASTE, True FISP, and oral contrast‐enhanced T1‐weighted sequences was able to depict juxtapapillary diverticula in our series. J. Magn. Reson. Imaging 2003;17:487–492. © 2003 Wiley‐Liss, Inc.
A manipulator system for 14‐gauge large core breast biopsies inside a high‐field whole‐body MR scanner
Authors: Pfleiderer Stefan O.R. , Reichenbach Jürgen R. , Azhari Tarek , Marx Christiane , Malich Ansgar , Schneider Achim , Vagner Jörg , Fischer Harald , Kaiser Werner A.
Published: March 2003

Purpose

To investigate a robotic manipulator system for MR‐guided breast biopsies inside a 1.5 T whole‐body magnet.

Materials and Methods

Fourteen patients with suspicious breast lesions (diameter 18.6 ± 12 mm) underwent biopsy. Patients with malignant findings underwent surgery afterwards and the histologic findings between biopsy and surgery were correlated.

Results

In five patients biopsy findings were histopathologically confirmed following open surgery. One tubular carcinoma was missed; one invasive cancer was underestimated. Seven patients with benign findings are still in the follow‐up period.

Conclusion

The study demonstrates the feasibility to perform breast biopsies inside the magnet of a whole‐body MR scanner by using a manipulator system. J. Magn. Reson. Imaging 2003;17:493–498. © 2003 Wiley‐Liss, Inc.
Modelling evapotranspiration at three boreal forest stands using the CLASS: tests of parameterizations for canopy conductance and soil evaporation
Authors: Bartlett Paul A. , Harry McCaughey J. , Lafleur Peter M. , Verseghy Diana L.
Published: March 2003

The performance of the Canadian Land Surface Scheme (CLASS) was evaluated in off‐line runs, using data collected at three boreal forest stands located near Thompson, Manitoba: young jack pine, mature jack pine, and mature black spruce. The data were collected in the late spring through autumn of 1994 and 1996, as part of the Boreal Ecosystem–Atmosphere Study (BOREAS).

The diurnal range in modelled soil heat flux was exaggerated at all sites. Soil evaporation was modelled poorly at the jack pine stands, with overestimation common and a step change to low evaporation as the soil dried. Replacing the soil evaporation algorithm, which was based on the estimation of a surface relative humidity value, with one based on soil moisture in the top soil layer reduced the overestimation and eliminated the step changes. Modelled water movement between soil layers was too slow at the jack pine stands. Modifying the soil hydraulic parameters to match an observed characteristic curve at the young jack pine stand produced a soil water suction that agreed more closely with measurements and improved drainage between soil layers.

The latent heat flux was overestimated and the sensible heat flux underestimated at all three stands. New Jarvis–Stewart‐type canopy conductance algorithms were developed from stomatal conductance measurements. At the jack pine stands, stomatal conductance scaled by leaf area index reproduced canopy conductance, but a reduction in the scaled stomatal conductance by one half was necessary at the black spruce stand, indicating a nonlinearity in the scaling of stomatal conductance for this ecosystem. The root‐mean‐squared error for daily average latent heat flux for the control run of the CLASS and for the best test run are 49 W m−2 and 14 W m−2 respectively at the young jack pine stand, 50 W m−2 and 15 W m−2 respectively at the old jack pine stand, and 48 W m−2 and 13 W m−2 respectively at the old black spruce stand. Copyright © 2003 Royal Meteorological Society
Impact of the extratropical dynamical modes upon troposphere temperature using an approach based on advection of temperature
Authors: Gimeno Luis , Vidal Oscar , Nieto Raquel , de la Torre Laura , García Ricardo , Hernández Emiliano , Bojariu Roxana , Ribera Pedro , Gallego David
Published: March 2003

Advection of temperature (AT) is used to diagnose the influence of changes in extratropical atmospheric circulation on air temperature. AT is calculated at three different pressure levels (850, 500 and 200 hPa) for the period 1958–98 using NCEP–NCAR reanalysis data. Global and hemispheric annual series of AT have a common feature consisting of positive values and trends at 850 and 500 hPa and negative values and trends at 200 hPa, together with quasi‐biennial and quasi‐quadrennial oscillations for most of the series. Significant correlations were found between most of the Northern Hemisphere and global AT series with the Arctic oscillation and between most of the Southern Hemisphere and global AT series with the Antarctic oscillation. Copyright © 2003 Royal Meteorological Society