bluuebunny/crossref_metadata_2025 huggingface dataset:
Sense of community in science fiction fandom, Part 2: Comparing neighborhood and interest group sense of community
Authors: Obst Patricia , Zinkiewicz Lucy , Smith Sandy G.
Published: August 2002

There is much debate in community psychology literature as to the dimensions underlying the psychological sense of community (PSOC) construct. One of the few theoretical discussions is that of McMillan and Chavis (1986), who hypothesized four dimensions: Belonging, Fulfillment of Needs, Influence, and Shared Emotional Connection. Debate has also emerged regarding the role of identification within PSOC. However, few studies have explored the place of identification in PSOC. In addition, whereas PSOC has been applied to both communities of interest and geographic communities, to date little research has compared a single group's PSOC with a community of interest to their PSOC with their geographic communities. The current study explored PSOC with participants' interest and geographic communities in a sample (N = 359) of members of science fiction fandom, a community of interest with membership from all over the world. Support emerged for McMillan and Chavis' (1986) four dimensions of PSOC, both within participants' PSOC with their geographic communities and with their community of interest, with the addition of a fifth dimension, that of Conscious Identification. All dimensions emerged as significant predictors of overall sense of community in both community types. Participants reported higher levels of global PSOC with fandom than with their geographic communities, a pattern that also emerged across all factors separately. These results, and implications for PSOC research, are discussed. © 2002 John Wiley & Sons, Inc.
EGFR‐independent activation of ERK1/2 mediates growth inhibition by a PTPase antagonizing K‐vitamin analog
Authors: Kar Siddhartha , Adachi Takahito , Carr Brian I.
Published: August 2002

The K‐vitamin analog Cpd 5 or [2‐(2‐mercaptoethanol)‐3‐methyl‐1,4‐napthoquinone] is a potent cell growth inhibitor in vitro and in vivo, likely due to arylation of enzymes containing a catalytic cysteine. This results in inhibition of protein tyrosine phosphatase (PTPase) activity with resultant hyperphosphorylation of EGF receptors (EGFR) and ERK1/2 protein kinases, which are downstream to EGFR in the MAPK pathway. We used NR6 fibroblast cells, which lack endogenous EGFR and its variant cells transfected with different EGFR mutants to assess the contribution of the EGFR‐mediated signaling pathway to Cpd 5‐mediated ERK activation and cell growth inhibition. Cpd 5 treatment resulted in enhanced phosphorylation of EGFR at carboxyl‐terminal tyrosines. This phosphorylation and activation of EGFR were found to be necessary neither for growth inhibition nor for the activation of the downstream kinases ERK1/2, since both occurred in EGFR‐devoid mutant cells. U0126 and PD 098059, specific inhibitors of MEK1/2, the ERK1/2 kinases, antagonized both cell growth inhibition and ERK1/2 phosphorylation mediated by Cpd5. Cpd 5 was also found to inhibit ERK1/2 phosphatase(s) activity in lysates from all the cells tested, irrespective of their EGFR status. These results show that EGFR‐independent ERK1/2 phosphorylation was involved in the mechanism of Cpd5 mediated growth inhibition. This is likely due to the observed antagonism of ERK phosphatase activity. A candidate PTPase was found to be Cdc25A, a recently identified ERK phosphatase. J. Cell. Physiol. 190: 356–364, 2002. © 2002 Wiley‐Liss, Inc.
Tpl‐2 induces apoptosis by promoting the assembly of protein complexes that contain caspase‐9, the adapter protein Tvl‐1, and procaspase‐3
Authors: Patriotis Christos , Russeva Maria G. , Lin Jun‐Hsiang , Srinivasula Srinivasa M. , Markova Dessislava Z. , Tsatsanis Christos , Makris Antonios , Alnemri Emad S. , Tsichlis Philip N.
Published: August 2002

The Tpl‐2 proto‐oncoprotein promotes cellular proliferation when overexpressed in a variety of tumor cell lines. Here, we present evidence that when overexpressed in immortalized non‐transformed cells, Tpl‐2 induces apoptosis by promoting the activation of caspase‐3 via a caspase‐9‐dependent mechanism, and that apoptosis is enhanced when Tpl‐2 is co‐expressed with the newly identified ankyrin repeat protein Tvl‐1. The activation of caspase‐3 by caspase‐9 is known to depend on the assembly of a multimolecular complex that includes Apaf‐1 and caspase‐9. Data presented here show that co‐expression of Tpl‐2 with Tvl‐1 promotes the assembly of a complex that involves several proteins that bind Apaf‐1 including Tvl‐1, itself, Tpl‐2 and phosphorylated procaspase‐9. More important, procaspase‐3, which under normal growth conditions is not associated with the complex, binds Tvl‐1 conditionally in response to Tpl‐2–generated apoptotic signals. The conditional association of procaspase‐3 with Tvl‐1 promotes the in vivo proteolytic maturation of procaspase‐3 by caspase‐9, a process casually linked to apoptosis. © 2001 Wiley‐Liss, Inc.
Selective reverse micellar extraction of penicillin acylase from E coli
Authors: Gaikar Vilas G , Kulkarni Madhav S
Published: August 2002

The recovery of penicillin acylase from E coli by a new reverse micellar treatment is described. The results are compared with the cell disruption by ultrasound followed by reverse micellar extraction. The process gave selective extraction of penicillin acylase directly from the periplasmic space of E coli without disrupting the cells. Unlike ultrasonication which breaks open the cells entirely, making subsequent processing difficult and expensive, reverse micellar treatment of cells gave a moderate recovery of 60% of enzyme activity in a highly pure form.

© 2001 Society of Chemical Industry
Production of fructose and ethanol from media with high sucrose concentrations by a mutant of Saccharomyces cerevisiae
Authors: Atiyeh Hasan , Duvnjak Zdravko
Published: August 2002

The production of enriched fructose syrups and ethanol from a synthetic medium with high sucrose concentrations was studied in a batch process using Saccharomyces cerevisiae ATCC 36858. The results showed that the fructose yield was above 92% of theoretical values in synthetic media with sucrose concentrations between 180 g dm−3 and 726 g dm−3. Ethanol yield was about 82% in media with sucrose concentrations up to 451 g dm−3. A product containing 178 g dm−3 fructose, which represents 97% of the total sugar content, and 79 g dm−3 ethanol was obtained using a medium with 360 g dm−3 sucrose. The fructose fraction in the carbohydrates content in the produced syrups decreased with increases in the initial sucrose concentration. In a medium with initial sucrose concentration of 574 g dm−3, the fructose content in the produced broth was 59% of the total carbohydrates. Glycerol and fructo‐oligosaccharides were also produced in this process. The produced fructo‐oligosaccharides started to be consumed when the concentration of sucrose in the media was less than 30% of its initial value. Complete hydrolysis of these sugars was noticed in media with sucrose concentrations below 451 g dm−3. These findings will be useful in the production of ethanol and high fructose syrups using sucrose‐based raw materials with high concentrations of this carbohydrate.

© 2001 Society of Chemical Industry
Mortality among workers at a plastics manufacturing plant
Authors: Sathiakumar Nalini , Delzell Elizabeth , Cole Philip , Larson Rodney
Published: August 2002

This study evaluated the 1970–1993 mortality experience of 2550 of white and black men employed at a Texas plastics plant that made polyethylene, polypropylene, K‐resin (a copolymer of 1,3‐butadiene and styrene) and other materials. Of particular interest was the relationship between work in plastics manufacturing and colorectal cancer, as certain epidemiological investigations have reported an increase in this form of cancer among workers with potential exposure to polypropylene.

Overall, subjects had fewer than expected deaths from all causes combined (269 observed/364.3 expected), from all cancer (79/89.3) and from colorectal cancer (5/9.5). Polypropylene workers had one observed compared with 0.4 expected death from colorectal cancer. A two‐fold increase in deaths from accidents among hourly men was attributable to an explosion in the polyethylene area. Certain subgroups of workers had a slight increase in lung cancer deaths. These results were not statistically significant, did not display marked patterns with duration of employment or time since hire and were not clearly attributable to occupational exposure. Some subgroups of employees had more than expected deaths from oesophagus cancer, pancreas cancer and prostate cancer. These findings were based on small numbers, and there is no persuasive evidence that the excesses were due to chemicals at the plant. However, longer follow‐up will be necessary to obtain more precise results for subjects with long‐term employment and with long potential induction time. Copyright © 1999 John Wiley & Sons, Ltd.
Pododermal angioarchitecture of the bovine claw in relation to form and function of the papillary body: A scanning electron microscopic study
Authors: Hirschberg Ruth M. , Mülling Christoph K. W. , Budras Klaus‐Dieter
Published: August 2002

The region‐specific angioarchitecture of the bovine pododerma was examined using systematic scanning electron microscopy of micro‐corrosion casts of juvenile and adult bovine claws. Particular emphasis was laid on the demonstration of specialised vascular structures such as arteriovenous anastomoses. Comparing the results of main and dew claws, respectively, of juvenile and adult claws, a relation between burdening of the claw and density and differentiation of the pododermal papillary and lamellar blood vessels was detected. The results suggest a possible influence of body weight (or age) and weight‐bearing on the formation and vascularisation of the pododermal papillary body. The lamellar and papillary microvascularisation and microcirculation are discussed. Microsc. Res. Tech. 54:375–385, 2001. © 2001 Wiley‐Liss, Inc.
Selective enhanced phosphorylation of shrimp β‐tubulin by PKC‐δ with PEPtaxol, a synthetic peptide encoding the taxol binding region
Authors: Chen Wen‐Yi , Yang Yu‐Ming , Chuang Nin‐Nin
Published: August 2002

β‐tubulin cDNA from the shrimp Penaeus japonicus was isolated by homology cloning. Expression of cDNA in Escherichia coli yielded a 55 kDa polypeptide, positive for monoclonal antibodies against mammalian β‐tubulin. Autoradiography demonstrated the bacterially expressed hepatopancreas β‐tubulin of P. japonicus is specifically phosphorylated by the δ isoenzyme of protein kinase C (PKC‐δ) purified from the plasma membrane of the shrimp heart, in the presence of the receptor for activated PKC (RACK), but not in its absence. Purified shrimp heart PKC‐δ is able to phosphorylate bacterially expressed shrimp β‐tubulin without the presence of Ca++, but requires Mg++. The kinase activity of purified PKC‐δ on bacterially expressed β‐tubulin was enhanced by incubation with PEPtaxol, a synthetic peptide encoding the taxol‐binding region of β‐tubulin. In other words, PEPtaxol modulates the kinase activity of PKC‐δ through RACK. J. Exp. Zool. 292:376–383, 2002. © 2002 Wiley‐Liss, Inc.
Vascular anatomy of the fish gill
Authors: Olson Kenneth R.
Published: August 2002

The fish gill is the most physiologically diversified vertebrate organ, and its vasculature the most intricate. Application of vascular corrosion techniques that couple high‐fidelity resins, such as methyl methacrylate, with scanning electron microscopy yields three‐dimensional replicas of the microcirculation that have fostered a better appreciate gill perfusion pathways. This is the focus of the present review. Three vascular networks can be identified within the gill filament. The arterioarterial (respiratory) pathway consists of the lamellae and afferent and efferent segments of the branchial and filamental arteries and lamellar arterioles. The body of the filament contains two post‐lamellar pathways: the interlamellar and nutrient. The interlamellar system is an extensive ladder‐like network of thin‐walled, highly distensible vessels that traverses the filament between, and parallel to, the lamellae and continues around the afferent and efferent borders of the filament. Interlamellar vessels are supplied by short, narrow‐bore feeder vessels from the medial wall of the efferent filamental artery. A myriad of narrow‐bore, tortuous arterioles arise from the basal efferent filamental artery and efferent branchial artery and anastomose to form the nutrient circulation of the arch and filament. In the filament body, nutrient capillaries and interlamellar vessels are often closely associated, and the former may ultimately drain into the latter. Many of the anatomical characteristics of interlamellar vessels are strikingly similar to those of mammalian lymphatic capillaries, with the exception that interlamellar vessels are directly fed by arteriovenous‐like anastomoses. It is likely that gill interlamellar and mammalian lymphatics are physiologically, if not embryologically, equivalent. © 2002 Wiley‐Liss, Inc.
Globin gene transfer for the treatment of severe hemoglobinopathies: a paradigm for stem cell‐based gene therapy
Authors: Sadelain Michel
Published: August 2002

The prospect of treating blood disorders with genetically modified stem cells is highly promising. This therapeutic approach, however, raises a number of fundamental biological questions, spanning several research fields. Further investigation is required to better understand how to isolate and efficiently transduce hematopoietic stem cells (HSCs), while preserving optimal homing and self‐renewing properties; how to design safe vectors permitting controlled expression of the transgene products; and how to promote host repopulation by engrafted HSCs. This article addresses basic issues in stem cell‐based gene therapy from the perspective of regulating transgene expression, taking globin gene transfer for the treatment of severe hemoglobinopathies as a paradigm. Copyright © 2002 John Wiley & Sons, Ltd.
Recursive constructions for triangulations
Authors: Grannell M. J. , Griggs T. S. , Širáň J.
Published: August 2002

Three recursive constructions are presented; two deal with embeddings of complete graphs and one with embeddings of complete tripartite graphs. All three facilitate the construction of 2) non‐isomorphic face 2‐colourable triangulations of Kn and Kn,n,n in orientable and non‐orientable surfaces for values of n lying in certain residue classes and for appropriate constants a. © 2002 John Wiley & Sons, Inc. J Graph Theory 39: 87–107, 2002
Total choosability of multicircuits II
Authors: Kostochka Alexandr V. , Woodall Douglas R.
Published: August 2002

A multicircuit is a multigraph whose underlying simple graph is a circuit (a connected 2‐regular graph). In this paper, the method of Alon and Tarsi is used to prove that all multicircuits of even order, and some regular and near‐regular multicircuits of odd order have total choosability (i.e., list total chromatic number) equal to their ordinary total chromatic number. This completes the proof that every multicircuit has total choosability equal to its total chromatic number. In the process, the total chromatic numbers of all multicircuits are determined. © 2002 Wiley Periodicals, Inc. J Graph Theory 40: 44–67, 2002
Tension polynomials of graphs
Authors: Kochol Martin
Published: August 2002

The tension polynomial FG(k) of a graph G, evaluating the number of nowhere‐zero ℤk‐tensions in G, is the nontrivial divisor of the chromatic polynomial χG(k) of G, in that χG(k) = kc(G)FG(k), where c(G) denotes the number of components of G. We introduce the integral tension polynomial IG(k), which evaluates the number of nowhere‐zero integral tensions in G with absolute values smaller than k. We show that 2r(G)FG(k)≥IG(k)≥ (r(G)+1)FG(k), where r(G)=|V(G)|−c(G), and, for every k>1, FG(k+1)≥ FG(k)˙k / (k−1) and IG(k+1)≥IG(k)˙k/(k−1). © 2002 Wiley Periodicals, Inc. J Graph Theory 40: 137–146, 2002
(Physio)logical circuits: The intellectual origins of the McCulloch–Pitts neural networks
Authors: Abraham Tara H.
Published: August 2002

This article examines the intellectual and institutional factors that contributed to the collaboration of neuropsychiatrist Warren McCulloch and mathematician Walter Pitts on the logic of neural networks, which culminated in their 1943 publication, “A Logical Calculus of the Ideas Immanent in Nervous Activity.” Historians and scientists alike often refer to the McCulloch–Pitts paper as a landmark event in the history of cybernetics, and fundamental to the development of cognitive science and artificial intelligence. This article seeks to bring some historical context to the McCulloch–Pitts collaboration itself, namely, their intellectual and scientific orientations and backgrounds, the key concepts that contributed to their paper, and the institutional context in which their collaboration was made. Although they were almost a generation apart and had dissimilar scientific backgrounds, McCulloch and Pitts had similar intellectual concerns, simultaneously motivated by issues in philosophy, neurology, and mathematics. This article demonstrates how these issues converged and found resonance in their model of neural networks. By examining the intellectual backgrounds of McCulloch and Pitts as individuals, it will be shown that besides being an important event in the history of cybernetics proper, the McCulloch–Pitts collaboration was an important result of early twentieth‐century efforts to apply mathematics to neurological phenomena. © 2002 Wiley Periodicals, Inc.
Finance for the poor: from microcredit to microfinancial services
Authors: Matin Imran , Hulme David , Rutherford Stuart
Published: August 2002

This paper reviews the achievements of the ‘microfinance revolution’, through reference to the now extensive literature. It finds that there are many opportunities to improve and innovate. To illustrate this finding, the paper concentrates on examining what we need to know to design and deliver better financial products to the poor, especially the poorest. It argues that financial services for the poor are essentially a matter of helping the poor turn their savings into sums large enough to satisfy a wide range of business, consumption, personal, social and asset‐building needs. The range of such ‘swaps’ should be wide enough to cater for short, medium and long‐term needs, and they must be delivered in ways which are convenient, appropriate, safe and affordable. Providing poor people with effective financial services helps them deal with vulnerability and can thereby help reduce poverty. However, the relationship is driven by complex livelihood imperatives and is not simple. Microfinance is not a magic sky‐hook that reaches down to pluck the poor out of poverty. It can, however, be a strategically vital platform that the poor can use to raise their own prospects for an escape from poverty. Copyright © 2002 John Wiley & Sons, Ltd.
Gut‐associated cells of derocheilocaris remanei (crustacea, mystacocarida)
Authors: Fernández Isabel , Herrera‐Álvarez Letizia , Pardos Fernando , Benito Jesús
Published: August 2002

The gut‐associated cells (GA‐cells) of the mystacocarid Derocheilocaris remanei were investigated by transmission electron microscopy. These cells are characterized by a dense cytoplasm, the presence of clear vesicles adjacent to the gut epithelium, glycogen, and lipid droplets. GA‐cells envelop the midgut and hindgut and send blunt cytoplasmic extensions to the gut epithelium through its basal lamina. The GA‐cells also extend dorsolateral projections to the body wall by means of intermediate cells. In addition to a mechanical function of suspending and stabilizing the gut, these cells may affect the flow of the hemocoelic fluid and may be implicated in the processes of transport, assimilation, and storage of nutrients. J. Morphol. 251:276–283, 2002. © 2002 Wiley‐Liss, Inc.
Possible ctenophoran affinities of the precambrian “sea‐pen”Rangea
Authors: Dzik Jerzy
Published: August 2002

The Namibian Kuibis Quartzite fossils ofRangeaare preserved three‐dimensionally owing to incomplete collapse of the soft tissues under the load of instantaneously deposited sand. The process of fossilization did not reproduce the original external morphology of the organism but rather the inner surface of collapsed organs, presumably a system of sacs connected by a medial canal. The body ofRangeahad tetraradial symmetry, a body plan shared also by the White Sea Russian fossilBomakelliaand possibly some other Precambrian frond‐like fossils. They all had a complex internal anatomy, smooth surface of the body, and radial membranes, making their alleged colonial nature unlikely. Despite a different style of preservation, the Middle Cambrian Burgess Shale frond‐likeThaumaptilonshows several anatomical similarities toRangea. The body plan of the Burgess Shale ctenophoreFasciculus, with its numerous, pinnately arranged comb organs, is in many respects transitional betweenThaumaptilonand the Early Cambrian ctenophoreMaotianoascusfrom the Chengjiang fauna of South China. It is proposed that the irregularly distributed dark spots on the fusiform units of the petaloid ofThaumaptilonrepresent a kind of macrocilia and that the units are homologous with the ctenophoran comb organs. These superficial structures were underlain by the complex serial organs, well represented in the fossils ofRangea. The Precambrian “sea‐pens” were thus probably sedentary ancestors of the ctenophores. J. Morphol. 252:315–334, 2002. © 2002 Wiley‐Liss, Inc.
Time course of contrast enhancement patterns after Gd‐BOPTA in correlation to myocardial infarction and viability: A feasibility study
Authors: Sandstede Joern J.W. , Beer Meinrad , Lipke Claudia , Pabst Thomas , Kenn Werner , Harre Kerstin , Neubauer Stefan , Hahn Dietbert
Published: August 2002

Our objective was to analyze contrast enhancement patterns (CEP) and their time course after myocardial infarction (MI) following injection of Gd‐BOPTA in correlation with recovery of regional function. Seven patients with subacute MI (18 ± nine days) were examined before, as well as three and six (n = six) months after, revascularization of the infarct‐related artery. Regional wall motion abnormalities were assessed by cine‐MRI, and repetitive images of one representative slice were acquired up to 45 minutes after 0.05 mmol/kg Gd‐BOPTA using a T1‐w TSE‐sequence. Two patients showed mid‐wall/subendocardial, one patient subendocardial enhancement of MI associated with mechanical improvement after revascularization. Three patients without improvement revealed a mid‐wall hypoenhanced zone within the first five minutes after injection, which was unchanged at follow‐up. One patient with partial functional improvement showed transmural enhancement and a mid‐wall hypoenhanced zone in adjacent areas. With this feasibility study, we concluded that mid‐wall and/or subendocardial enhancement after Gd‐BOPTA was associated with viable myocardium, whereas detection of microvascular obstruction correlating with scar formation is suggested by mid‐wall hypoenhancement within the first five minutes after injection. J. Magn. Reson. Imaging 2001;14:789–794. © 2001 Wiley‐Liss, Inc.
Evaluation of free‐breathing three‐dimensional magnetic resonance coronary angiography with hybrid ordered phase encoding (HOPE) for the detection of proximal coronary artery stenosis
Authors: Bunce Nicholas H. , Jhooti Permi , Keegan Jennifer , Rahman Shelley L. , Bunce Catherine , Firmin David N. , Davies Simon W. , Lorenz Christine H. , Pennell Dudley J.
Published: August 2002

We evaluated free‐breathing, prospective navigator‐gated, three‐dimensional (3D) magnetic resonance coronary angiography (MRCA) with hybrid ordered phase‐encoding (HOPE), in the detection of proximal coronary artery stenosis. The coronary arteries were imaged in 46 patients undergoing cardiac catheterization. The mean scan time was 48 minutes. The mean arterial length (mm) visualized was left main stem (LMS) 11.7 (SD 4.5), left anterior descending (LAD) 30.1 (SD 11.1), circumflex (LCx) 15.5 (SD 8.6), and right (RCA) 56.2 (SD 20.8). Twenty‐three patients had coronary artery disease with 47 significant stenoses on cardiac catheterization. All LMS were normal on both catheterization and MRCA. MRCA sensitivity was highest for the LAD (89% CI 65%–99%) and RCA (76% CI 50%–93%), but lower for the LCx (50% CI 21%–79%). Specificity ranged from 72%–100%. Improvements in image quality, length of vessel seen, and specific imaging of the LCx are required for MRCA to become an alternative to cardiac catheterization. J. Magn. Reson. Imaging 2001;14:677–684. © 2001 Wiley‐Liss, Inc.
MR perfusion, diffusion and BOLD imaging of methotrexate‐exposed swine brain
Authors: Mäkiranta Minna J. , Lehtinen Satu , Jauhiainen Jukka P.T. , Oikarinen Jarkko T. , Pyhtinen Juhani , Tervonen Osmo
Published: August 2002

Purpose

To evaluate the methotrexate (MTX)‐exposed swine brain, functional magnetic resonance imaging (MRI), including perfusion, diffusion, and blood‐oxygen‐level‐dependent (BOLD) contrast imaging, was used.

Material and Methods

Juvenile pigs received either 2 × 5 g/m2, or 5 × 2 g/m2 MTX intravenously within one month. MRI was performed (sedative: propofol) before (14–17 kg, N = 6) and after (21–27 kg, N = 4) the MTX exposure. Also, age‐matched controls (22–27 kg, N = 4) were imaged.

Results

After the MTX exposure, reduced (from 2%–4% to 0%–1%) or negative (−2% to −3%) BOLD responses were detected; apparent diffusion coefficient (ADC) or relative perfusion values did not change.

Conclusion

This study suggests that MTX‐related changes in the brain may be detected as changes in flow‐metabolism coupling as reduced or negative response (for somatosensory activation) in the BOLD contrast MRI. The contrast agent perfusion MRI, without absolute quantification, may not show global damage in brain perfusion related to the MTX exposure in the swine model used. ADC (in one direction) may not indicate MTX‐related changes in the brain. J. Magn. Reson. Imaging 2002;15:511–519. © 2002 Wiley‐Liss, Inc.
Diffusion‐weighted MRI of cholesteatomas of the petrous bone
Authors: Fitzek Clemens , Mewes Torsten , Fitzek Sabine , Mentzel Hans‐Joachim , Hunsche Stefan , Stoeter Peter
Published: August 2002

Purpose

To investigate if primary cholesteatomas of the petrous bone show high signal in diffusion‐weighted imaging (DWI).

Materials and Methods

In this blinded study, we compared 15 patients with clinically certain cases and later surgically proven cholesteatomas vs. 12 patients with clinically acute otitis of the middle ear and 20 volunteers without petrous bone disease. Two blinded readers without knowledge of the clinical data decided in consensus agreement whether there was a pathologic signal increase in the petrous bone in an anisotropic single‐shot echo‐planar imaging (EPI) DWI sequence, an artifact, or no signal increase.

Results

Thirteen of 15 patients with cholesteatomas showed bright signal in EPI DWI, whereas 10 of 12 patients with acute otitis media and all volunteers presented the usual low signal of petrous bone.

Conclusion

EPI DWI is a fast diagnostic method that may be an additional valuable tool in the workup of suspected cholesteatomas. The ability of this technique to differentiate between cholesteatomas and granulomas or chronic otitis is not yet available. J. Magn. Reson. Imaging 2002;15:636–641. © 2002 Wiley‐Liss, Inc.
3D contrast‐enhanced MR angiography of the run‐off vessels: Value of image subtraction
Authors: Ruehm Stefan G. , Nanz Daniel , Baumann Andreas , Schmid Michaela , Debatin Jörg F.
Published: August 2002

The diagnostic gain associated with image subtractions was assessed regarding contrast‐enhanced 3D magnetic resonance angiography (MRA) image sets of the pelvic and lower extremity arteries. The MRA strategy combined a dedicated vascular coil with a single injection, two‐station protocol. Voxel‐by‐voxel signal intensity subtraction was performed on MRA image sets obtained before and during dynamic infusion of a para‐magnetic contrast agent. Non‐subtracted and subtracted MRA image sets were assessed for the presence of occlusive (four grades) disease, using DSA as the standard of reference. In addition, SNR and CNR were recorded for each vascular segment on both the non‐subtracted and subtracted images. While CNR values of subtracted images exceeded those of non‐subtracted images (P < 0.05), there was no difference in diagnostic performance. For the detection of hemodynamically significant disease, non‐subtracted and subtracted MRA provided overall sensitivity and specificity of 90.2%/90.3% and 95.1%/95.6%, respectively. Concordance between non‐subtracted and subtracted MRA was excellent (Kappa = 0.86). J. Magn. Reson. Imaging 2001;13:402–411. © 2001 Wiley‐Liss, Inc.
Pulmonary arteriovenous malformation: Characterization with time‐resolved ultrafast 3D MR angiography
Authors: Goyen Mathias , Ruehm Stefan G. , Jagenburg Andreas , Barkhausen Jörg , Kröger Knut , Debatin Jörg F.
Published: August 2002

To avoid potentially deadly consequences from paradoxical emboli, early detection and accurate characterization of pulmonary arteriovenous malformations (AVMs) is highly desirable. We report on a patient with a suspected pulmonary AVM who underwent ultrafast time‐resolved 3D MR angiography of the pulmonary arteries. The case documents the suitability of the MRA technique as a noninvasive alternative to computed tomographic angiography and digital subtraction angiography for accurate pre‐therapeutic characterization of pulmonary AVMs. J. Magn. Reson. Imaging 2001;13:458–460. © 2001 Wiley‐Liss, Inc.
Slow clearance gadolinium‐based extracellular and intravascular contrast media for three‐dimensional MR angiography
Authors: Bremerich Jens , Colet Jean Marie , Giovenzana Giovanni Battista , Aime Silvio , Scheffler Klaus , Laurent Sophie , Bongartz Georg , Muller Robert N.
Published: August 2002

The objective of this study was to assess two new slow‐clearance contrast media with extracellular and intravascular distribution for magnetic resonance angiography (MRA). Extracellular Gd‐DTPA‐BC2glucA and intravascular Gd(DO3A)3‐lys16 were developed within the European Biomed2 MACE Program and compared with two reference compounds, intravascular CMD‐A2‐Gd‐DOTA and extracellular GdDOTA, in 12 rats. Pre‐ and post‐contrast three‐dimensional MR (TR/TE = 5 msec/2.2 msec; isotropic voxel size 0.86 mm3) was acquired for 2 hours. Signal‐to‐noise enhancement (ΔSNR) was calculated. Two minutes after injection, all contrast media provided strong vascular signal enhancement. The ΔSNR for Gd‐DTPA‐BC2glucA, Gd(DO3A)3‐lys16, CMD‐A2‐Gd‐DOTA, and GdDOTA were 13.0 ± 1.8, 25.0 ± 3.2, 25.0 ± 4.0, and 18.0 ± 3.4, respectively. Gd‐DTPA‐BC2glucA, Gd(DO3A)3‐lys16, and CMD‐A2‐Gd‐DOTA cleared slowly from the circulation, whereas GdDOTA cleared rapidly. Vascular ΔSNR at 2 hours were 2.9 ± 0.6, 25.0 ± 3.2, 25.0 ± 4.0, and 0.4 ± 1.0. Gd(DO3A)3‐lys16 provided strong vascular and minor background enhancement, and thus may be useful for MRA or perfusion imaging. Gd‐DTPA‐BC2glucA produces persistent enhancement of extracellular water, and thus may allow quantification of extracellular distribution volume and assessment of myocardial viability. J. Magn. Reson. Imaging 2001;13:588–593. © 2001 Wiley‐Liss, Inc.
Gadolinium‐enhanced, vessel‐tracking, two‐dimensional coronary MR angiography: Single‐dose arterial‐phase vs. delayed‐phase imaging
Authors: Ho Vincent B. , Foo Thomas K. F. , Arai Andrew E. , Wolff Steven D.
Published: August 2002

The purposes of our study were to investigate the benefits of using a single dose of an extracellular contrast agent for coronary magnetic resonance angiography (CMRA) and to determine the relative benefits of arterial‐phase vs. delayed‐phase image acquisition. The right coronary artery was imaged in 10 healthy adults using a breath‐hold, two‐dimensional fast gradient echo pulse sequence designed for vessel tracking (multiphase, multislice image acquisition). Pre‐ and postcontrast CMRA was performed. Postcontrast imaging consisted of arterial‐ and delayed‐phase CMRA following a 15 mL bolus (single dose) of contrast media and of delayed‐phase imaging following a cumulative 45 mL contrast dose (triple dose). Contrast‐enhanced CMRA provided a significantly higher (P < 0.001) signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) than noncontrast CMRA. CNR was highest for single‐dose arterial‐phase CMRA (13.1 ± 4.5) and triple‐dose delayed‐phase CMRA (13.0 ± 4.8), followed by single‐dose delayed‐phase CMRA (8.4 ± 3.5) and noncontrast CMRA (4.2 ± 1.8). Single‐dose arterial‐phase CMRA provided the best visualization of the distal right coronary artery and was preferred for blinded physician assessments. We concluded that utilization of a single dose of extracellular contrast media improves CMRA, especially if timed for arterial‐phase imaging. J. Magn. Reson. Imaging 2001;13:682–689. © 2001 Wiley‐Liss, Inc.
Preferential arterial imaging using gated thick‐slice gadolinium‐enhanced phase‐contrast acquisition in peripheral MRA
Authors: Foo Thomas K.F. , Ho Vincent B. , Hood Maureen N. , Hess Sandra L. , Choyke Peter L.
Published: August 2002

Purpose: To investigate the feasibility of preferential arterial imaging using gadolinium‐enhanced thick‐slice phase‐contrast imaging. Methods: Six healthy volunteers were studied using a peripheral‐gated segmented k‐space CINE phase‐contrast pulse sequence using four views per RR interval with flow encoding in the superior‐inferior direction. Images at the level of the popiteal trifurcation were acquired postcontrast with different section thicknesses (4–8 cm) and VENC values (20–150 cm/sec), and phase‐difference processing. Results: The post‐gadolinium contrast‐enhanced thick‐slice phase‐contrast acquisitions demonstrated the ability to visualize the tibio‐peroneal (trifurcation) arteries, especially in systole. With MR contrast agents, the signal from blood is raised significantly above that of stationary tissue from T1 shortening such that the partial volume artifact is reduced in thick‐slice acquisitions. Furthermore, by selecting the VENC value as a function of the cardiac cycle, the noise floor can be raised to selectively suppress flow values less than that of the noise threshold, allowing better accentuation of arterial structures at systole. Conclusions: Thick‐slice phase‐contrast acquisition with phase‐difference processing has been observed to reduce partial volume artifacts when an MR contrast agent substantially increases signal in the vasculature over that of normal background tissue. Preferential arterial images can be obtained by either increasing the VENC value to selectively suppress signal from slow flow in the veins or by subtracting the diastolic phase image from the peak systolic phase image. J. Magn. Reson. Imaging 2001;13:714–721. © 2001 Wiley‐Liss, Inc.
Tumor microvascular characterization using ultrasmall superparamagnetic iron oxide particles (USPIO) in an experimental breast cancer model
Authors: Turetschek Karl , Roberts Timothy P. L. , Floyd Eugenia , Preda Anda , Novikov Viktor , Shames David M. , Carter Wayne O. , Brasch Robert C.
Published: August 2002

The diagnostic potential of ultrasmall superparamagnetic iron oxide particles (USPIO) for quantitative tumor microvessel characterization was assessed by kinetic analysis of dynamic magnetic resonance imaging (MRI) in a rodent breast cancer model. Microvascular characteristics (transendothelial permeability (KPS) and fractional plasma volume (fPV)) were estimated in 32 female Sprague Dawley rats, bearing breast tumors of varying malignancy. These values were compared to a prototype macromolecular contrast medium standard, albumin‐(GdDTPA)30. Transendothelial permeability (KPS) correlated significantly (P < 0.05) with the tumor grade (Scarff‐Bloom‐Richardson (SBR) score) for the USPIO (r = 0.36), as well as for the reference macromolecule, albumin‐(GdDTPA)30 (r = 0.54). Estimates for the fPV did not show a statistically significant correlation with the tumor grade for either contrast medium. In conclusion, USPIO‐enhanced MRI data were capable to characterize tumor microvessel properties in this breast cancer model: microvascular permeability (determined using USPIO) correlated significantly with tumor grade. Thus, quantitative estimation of microvascular characteristics in tumors could provide a surrogate of new vessel formation (angiogenesis) and thus a further important clinical indication for USPIO, in addition to MR angiography. J. Magn. Reson. Imaging 2001;13:882–888. © 2001 Wiley‐Liss, Inc.
In vivo magnetic resonance (MR) study of fatty liver: Importance of intracellular ultrastructural alteration for MR tissue parameters change
Authors: Chai Jyh‐Wen , Lin Yung‐Chang , Chen Jeon‐Hor , Wu Chia‐Chin , Lee Chien‐Pei , Chu Woei‐Chyn , Lee San‐Kan
Published: August 2002

Fatty liver is thought to have a shorter T1 relaxation time than normal liver tissue, due to the accumulation of triglyceride. Previous studies regarding T1 and T2 relaxation times, however, show widely different results. In order to elucidate the mechanism responsible for the changes and diversity of relaxation times in fatty liver, we created two animal models in 14 rabbits, one acute form (N = 6) and the other chronic form (N = 8). Four rabbits were taken as a control group. Tissue relaxation times and the magnetization transfer (MT) effect of the liver tissue in these two models were measured. The results were correlated with biochemical analysis of water and fat content and histological examination, including findings in light microscopy and electron microscopy. Although the fatty ratio in both forms of fatty liver was similar, their tissue relaxation rate and MT effect were significantly different. The acute form showed prolongation of both T1 and T2 relaxation times (512 ± 51 msec vs. 710 ± 95 msec and 39 ± 1.8 msec vs. 48 ± 3.7 msec, respectively) and a decrease of the MT effect (50 ± 5.1% vs. 38 ± 6.3%), compared to those of the control group and preinduction liver. The chronic form showed shorter T1 and T2 values (526 ± 36 msec vs. 406 ± 56 msec and 36 ± 1.6 msec vs. 33 ± 2.3 msec, respectively) and a stronger MT effect (21 ± 0.9% vs. 26 ± 2.3%). In acute form fatty liver, electron microscopic examination revealed dramatic subcellular changes, such as vesicular transformation, a markedly increased amount of smooth endoplasmic reticulum (SER), and disruption of the crista. These changes were not found in the chronic form fatty liver. From this study, we concluded that the ultrastructural alteration in the subcellular organelles of hepatocyte might play a crucial role for the chameleonic presentation of MR tissue parameters in fatty liver. J. Magn. Reson. Imaging 2001;14:35–41. © 2001 Wiley‐Liss, Inc.
Cerebral hemodynamic changes measured by gradient‐echo or spin‐echo bolus tracking and its correlation to changes in ICA blood flow measured by phase‐mapping MRI
Authors: Marstrand Jacob R. , Rostrup Egill , Rosenbaum Sverre , Garde Ellen , Larsson Henrik B.W.
Published: August 2002

Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC‐MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase‐mapping. Also examined was the effect of repeated bolus injections. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated by singular value decomposition (SVD) and by deconvolution using an exponential function as kernel. The results showed no dependency on calculation method. GE‐EPI measured a significant increase in CBF and CBV in response to ACZ, while SE‐EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE‐EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE‐EPI and change in ICA flow. In conclusion, GE‐EPI under the present condition was superior to SE‐EPI in monitoring cerebral vascular changes.J. Magn. Reson. Imaging 2001;14:391–400. © 2001 Wiley‐Liss, Inc.
Uncommon presentation of a giant biliary cystadenoma: Correlation between MRI and pathologic findings
Authors: Frahm Christian , Zimmermann Arthur , Heller Martin , Brossmann Joachim
Published: August 2002

An uncommon case of a giant mucinous biliary cystadenoma (BCA) of the liver is described. On T2‐weighted and STIR images, a large hyperintense cystic mass revealed some septations and multiple intracystic masses of similar size and shape and uniform signal intensity, which was isointense to liver parenchyma. On T1‐weighted images, intracystic bodies were obscured and the cyst was hyperintense. The magnetic resonance (MR) appearance of intracystic fluid and structures was not due to mucinous or proteinous or hyperproteinous material, but corresponded to clots floating within hemorrhagic fluid. J. Magn. Reson. Imaging 2001;14:649–652. © 2001 Wiley‐Liss, Inc.
Accurate mass measurement of DNA oligonucleotide ions using high‐resolution time‐of‐flight mass spectrometry
Authors: Koomen John M. , Russell William K. , Tichy Shane E. , Russell David H.
Published: August 2002

Matrix‐assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) time‐of‐flight mass spectrometry (TOFMS) play an essential role in the analysis of biological molecules, not only peptides and proteins, but also DNA and RNA. Tandem mass spectrometry used for sequence analysis has been a major focus of technological developments in mass spectrometry, but accurate mass measurements by high‐resolution TOFMS are equally important. This paper describes the role that high mass measurement accuracy can play in DNA composition assignment and discusses the influence of several parameters on mass measurement accuracy in both MALDI and ESI mass spectra. Five oligonucleotides (5–13mers) were used to test the resolving power and mass measurement accuracy obtained with MALDI and ESI instruments with reflectron TOF mass analyzers. The results from the experimental studies and additional theoretical calculations provide a basis to predict the practical utility of high‐resolution TOFMS for the analysis of larger oligonucleotides. Copyright © 2002 John Wiley & Sons, Ltd.
Molecular characterization of hepatitis C virus genotype 2a from the entire sequences of four isolates
Authors: Kurihara Chie , Ishiyama Narihiro , Nishiyama Yasumasa , Fukushi Shuetsu , Kageyama Tsutomu , Katayama Kazuhiko , Miura Soichiro
Published: August 2002

Genotype 2a hepatitis C virus (HCV) has different characteristics from genotype 1b, such as responsiveness to interferon therapy. Such type‐specific characteristics appear to be due to differences in the HCV genome sequence. The complete sequences of genotype 2a HCV genome isolated from four patients with chronic hepatitis C were determined, and nucleotide and deduced amino acid sequences were compared within genotype 2a, as well as between genotype 2a and 1b. Whereas the amino acid sequence similarity of the core region was highest within genotype 1b, the NS3 and NS4B regions of exhibited greater similarity than the core region in genotype 2a. The serine protease and helicase motifs in the NS3 region were well conserved in genotype 2a to the same degree as in genotype 1b. However, the putative secondary structure of 2a isolates was significantly different from that of the 1b isolates. Analysis of amino acid similarity between genotypes 2a and 1b revealed the lowest degree of similarity in the E1 region, followed by the NS2 and NS5A region. Sequences of genotype 2a in the interferon‐sensitivity determining region (ISDR) located in the NS5A region had a deletion of four amino acids compared with that of genotype 1b. When the ISDR of the genotype 2a was aligned for maximal similarity, it exhibited similarity of only 52.5–55.0% when compared with that of HCV‐J, which belongs to genotype 1b. These findings for the entire sequences of genotype 2a isolates will contribute to virological studies of HCV. J. Med. Virol. 64:466–475, 2001. © 2001 Wiley‐Liss, Inc.
Coupled particle light scattering: a new technique for serodiagnosis of Epstein‐Barr virus infection
Authors: Baetens D.G.A. , Van Renterghem L.M.L.
Published: August 2002

The Coupled Particle Light Scattering™ technique was evaluated for serological diagnosis of Epstein‐Barr Virus (EBV) infection. Two hundred ninety‐six patient sera selected from several clinical categories (acute infection, non‐primary infection, interfering non‐EBV infection, non‐infected) were tested for IgM and IgG antibodies (anti‐VCA, anti‐EBNA and anti‐EA). Determination of EBV IgG with Copalis multiplex was accurate when compared with Enzygnost® Anti‐EBV/IgG ELISA. Although the sensitivity of Copalis IgM for acute infections was 100% a positive IgM result did not always indicate an acute infection. Strong reactivity to IgG EA (ratio 3, 1) and IgG VCA (ratio 13, 3) correlated with persistent infection or reactivation. The Copalis™I has many advantages over the existing methods, such as the possibility to measure three semi‐quantitative IgG responses to three different EBV antigens simultaneously. J. Med. Virol. 64:519–525, 2001. © 2001 Wiley‐Liss, Inc.
Ketogenic diet, amino acid metabolism, and seizure control
Authors: Yudkoff Marc , Daikhin Yevgeny , Nissim Ilana , Lazarow Adam , Nissim Itzhak
Published: August 2002

The ketogenic diet has been utilized for many years as an adjunctive therapy in the management of epilepsy, especially in those children for whom antiepileptic drugs have not permitted complete relief. The biochemical basis of the dietary effect is unclear. One possibility is that the diet leads to alterations in the metabolism of brain amino acids, most importantly glutamic acid, the major excitatory neurotransmitter. In this review, we explore the theme. We present evidence that ketosis can lead to the following: 1) a diminution in the rate of glutamate transamination to aspartate that occurs because of reduced availability of oxaloacetate, the ketoacid precursor to aspartate; 2) enhanced conversion of glutamate to GABA; and 3) increased uptake of neutral amino acids into the brain. Transport of these compounds involves an uptake system that exchanges the neutral amino acid for glutamine. The result is increased release from the brain of glutamate, particularly glutamate that had been resident in the synaptic space, in the form of glutamine. These putative adaptations of amino acid metabolism occur as the system evolves from a glucose‐based fuel economy to one that utilizes ketone bodies as metabolic substrates. We consider mechanisms by which such changes might lead to the antiepileptic effect. © 2001 Wiley‐Liss, Inc.