bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbohydrate solution simulations: Producing a force field with experimentally consistent primary alcohol rotational frequencies and populations
Authors: Kuttel Michelle , Brady J. W. , Naidoo Kevin J.
Published: October 2002

We present a CHARMM Carbohydrate Solution Force Field (CSFF) suitable for nanosecond molecular dynamics computer simulations. The force field was derived from a recently published sugar parameter set.1 Dihedral angle parameters for the primary alcohol as well as the secondary hydroxyl groups were adjusted. Free energy profiles of the hydroxymethyl group for two monosaccharides (β‐D‐glucose and β‐D‐galactose) were calculated using the new parameter set and compared with similar force fields. Equilibrium rotamer populations obtained from the CSFF are in excellent agreement with NMR data (glucose gg:gt:tg ≈ 66:33:1 and galactose gg:gt:tg ≈ 4:75:21). In addition, the primary alcohol rotational frequency is on the nanosecond time scale, which conforms to experimental observations. Equilibrium population distributions of the primary alcohol conformers for glucose and galactose are reached within 10 nanoseconds of molecular dynamics simulations. In addition, gas phase vibrational frequencies computed for β‐D‐glucose using this force field compare well with experimental frequencies. Carbohydrate parameter sets that produce both conformational energies and rotational frequencies for the pyranose primary alcohol group that are consistent with experimental observations should allow for increased accuracy in modeling the flexibility of biologically important (1‐6)‐linked saccharides in solution. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1236–1243, 2002
Application of the frozen atom approximation to the GB/SA continuum model for solvation free energy
Authors: Guvench Olgun , Weiser Jörg , Shenkin Peter , Kolossváry István , Still W. Clark
Published: October 2002

The generalized Born/surface area (GB/SA) continuum model for solvation free energy is a fast and accurate alternative to using discrete water molecules in molecular simulations of solvated systems. However, computational studies of large solvated molecular systems such as enzyme–ligand complexes can still be computationally expensive even with continuum solvation methods simply because of the large number of atoms in the solute molecules. Because in such systems often only a relatively small portion of the system such as the ligand binding site is under study, it becomes less attractive to calculate energies and derivatives for all atoms in the system. To curtail computation while still maintaining high energetic accuracy, atoms distant from the site of interest are often frozen; that is, their coordinates are made invariant. Such frozen atoms do not require energetic and derivative updates during the course of a simulation. Herein we describe methodology and results for applying the frozen atom approach to both the generalized Born (GB) and the solvent accessible surface area (SASA) parts of the GB/SA continuum model for solvation free energy. For strictly pairwise energetic terms, such as the Coulombic and van‐der‐Waals energies, contributions from pairs of frozen atoms can be ignored. This leaves energetic differences unaffected for conformations that vary only in the positions of nonfrozen atoms. Due to the nonlocal nature of the GB analytical form, however, excluding such pairs from a GB calculation leads to unacceptable inaccuracies. To apply a frozen‐atom scheme to GB calculations, a buffer region within the frozen‐atom zone is generated based on a user‐definable cutoff distance from the nonfrozen atoms. Certain pairwise interactions between frozen atoms in the buffer region are retained in the GB computation. This allows high accuracy in conformational GB comparisons to be maintained while achieving significant savings in computational time compared to the full (nonfrozen) calculation. A similar approach for using a buffer region of frozen atoms is taken for the SASA calculation. The SASA calculation is local in nature, and thus exact SASA energies are maintained. With a buffer region of 8 Å for the frozen‐atom cases, excellent agreement in differences in energies for three different conformations of cytochrome P450 with a bound camphor ligand are obtained with respect to the nonfrozen cases. For various minimization protocols, simulations run 2 to 10.5 times faster and memory usage is reduced by a factor of 1.5 to 5. Application of the frozen atom method for GB/SA calculations thus can render computationally tractable biologically and medically important simulations such as those used to study ligand–receptor binding conformations and energies in a solvated environment. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 214–221, 2002
Hyperovals in nets of small degree
Authors: Drake David A.
Published: October 2002

The existence of an r‐net of order n with a hyperoval is proved for r = 5 when n ≥ 63; for r = 7 when n ≥ 84; for r = 9 when n ≥ 59,573 and for r = 15 when n ≥ 1, 873,273. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 322–334, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10018
Lotto design tables
Authors: Li P. C. , van Rees G. H. J.
Published: October 2002

An LD(n,k,p,t;b) lotto design is a set of b k‐sets (blocks) of an n‐set such that any p‐set intersects at least one k‐set in t or more elements. Let L(n,k,p,t) denote the minimum number of blocks in any LD(n,k,p,t;b) lotto design. We will list the known lower and upper bound theorems for lotto designs. Since many of these bounds are recursive, we will incorporate this information in a set of tables for lower and upper bounds for lotto designs with small parameters. We will also use back‐track algorithms, greedy algorithms, and simulated annealing to improve the tables. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 335–359, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10020
Mentoring relationships for youth: Investigation of a process‐oriented model
Authors: Parra Gilbert R. , DuBois David L. , Neville Helen A. , Pugh‐Lilly Aalece O. , Povinelli Nan
Published: October 2002

We investigated a process‐oriented model of mentoring using data on 50 relationships in a Big Brothers/Big Sisters program. Data were collected on a monthly basis from both mentors and youth over a one‐year period; relationship benefits for youth were assessed at the end of the year by each type of informant. The degree to which relationships were continued throughout the one‐year period also was assessed. Path analyses using both youth and mentor report data revealed relations among study variables consistent with the proposed model. Mentors' ratings of their efficacy, obtained prior to the start of relationships, predicted greater amounts of mentor/youth contact as well as more positive experiences in relationships (e.g., fewer obstacles). Feelings of closeness between mentors and youth, in turn, were a final common component in model pathways that linked mentor/youth contact and most other measures to greater perceived benefits and relationship continuation. Implications for the design and evaluation of mentoring programs for youth are discussed. © 2002 Wiley Periodicals, Inc.
Who supports? The providers of social support to dual‐parent families caring for young children
Authors: Miller R. Jeff , Darlington Yvonne
Published: October 2002

Previous research points to the importance of both kin and non‐kin ties within social networks as sources of social support. This study examines the kin and non‐kin providers of specific types of support to dual‐parent low‐income Australian families caring for young children. The study highlights the importance of family and friends as support providers. Study participants tended to rely on family, including parents, siblings and other family members, and friends for emotional and information support. Parents also tended to provide material and practical support. While neighbors and community agencies offered some emotional and information support, overall, these sources were minimal.© 2002 Wiley Periodicals, Inc.
Insights into electromagnetic interaction mechanisms
Authors: Goodman Reba , Blank Martin
Published: October 2002

Low frequency (< 300 Hz) electromagnetic (EM) fields induce biological changes that include effects ranging from increased enzyme reaction rates to increased transcript levels for specific genes. The induction of stress gene HSP70 expression by exposure to EM fields provides insight into how EM fields interact with cells and tissues. Insights into the mechanism(s) are also provided by examination of the interaction of EM fields with moving charges and their influence on enzyme reaction rates in cell‐free systems. Biological studies with in vitro model systems have focused, in general, on the nature of the signal transduction pathways involved in response to EM fields. It is likely, however, that EM fields also interact directly with electrons in DNA to stimulate biosynthesis. Identification of an EM field‐sensitive DNA sequence in the heat shock 70 (HSP70) promoter, points to the application of EM fields in two biomedical applications: cytoprotection and gene therapy. EM field induction of the stress protein hsp70 may also provide a useful biomarker for establishing a science‐based safety standard for the design of cell phones and their transmission towers. © 2002 Wiley‐Liss, Inc.
Color doppler sonographic finding of retrograde jugular venous flow as a sign of innominate vein occlusion
Authors: Conkbayir Işik , Men Süleyman , Yanik Bahar , Hekimoğlu Baki
Published: October 2002

Occlusion or stenosis of the superior vena cava, the innominate vein, or both is an important clinical problem that requires prompt diagnosis. To confirm a suspected occlusion, imaging studies revealing the obstruction and the presence of collateral venous routes are needed. Color Doppler sonography (CDUS) is widely used to evaluate suspected venous thrombosis and collateral pathways. We present the CDUS findings in 2 cases of innominate vein occlusion. In case 1, CDUS of the neck and left upper arm, which harbored a permanent hemodialysis access, showed engorged veins in the upper arm, a patent dialysis access, and some collateral veins in the axilla. The subclavian and internal jugular veins were patent, but the flow in the left internal jugular vein was reversed. The left innominate vein was occluded. In case 2, CDUS of the upper arms showed that the veins, the dialysis access in the left upper arm, and the subclavian and jugular veins were patent, but the flow in the left internal jugular vein and in the right subclavian vein was reversed. Collateral veins were seen in the right axillary region. Both innominate veins were occluded. The resulting collateral pathways, ie, retrograde flow in the ipsilateral jugular vein crossing to the contralateral jugular vein through dural sinuses, were confirmed by venography in both cases. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:392–398, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.10081
Expression and regulatory role of receptors for vasoactive intestinal peptide in bone cells
Authors: Lundberg Pernilla , Lerner Ulf H.
Published: October 2002

An intense network of nerve fibers can be demonstrated in skeletal tissues, not only in the periosteum but also within cortical bone, growth plate, and bone marrow. This neuro‐osteogenic network expresses a restricted number of signalling molecules, including neuropeptides, neurotransmitters, and neurotrophins. Several lines of evidence indicate that receptors for these molecules are present on bone cells and that activation of these receptors leads to changes in bone cell activities. In addition, deletion of signalling molecules has been shown to alter bone metabolism. In the present review, these studies are summarized with a focus on distribution and effects of vasoactive intestinal peptide. Microsc. Res. Tech. 58:98–103, 2002. © 2002 Wiley‐Liss, Inc.
Cell and molecular biology of human olfaction
Authors: Rawson Nancy E. , Gomez George
Published: October 2002

Progress in our understanding of olfactory receptor physiology has progressed greatly over the past 10 years. It has become clear that many anatomical and molecular features of the peripheral aspect of the olfactory system have remained highly conserved across diverse species. Yet, this structure is responsible for conveying a wide variety of information about the environment that is necessary to the successful location of food, mates, and avoidance of danger, and it is thus not surprising that specializations have also evolved to suit the differing needs of different species. While the basic anatomical features reflect those of other mammals, functional studies of human olfactory receptor neurons have revealed physiological features both similar to and differing from those of other mammalian species. This review presents an overview of both the anatomical and physiological data describing the cell and molecular biology of the peripheral human olfactory system and how it functions in health and disease. Microsc. Res. Tech. 58:142–151, 2002. © 2002 Wiley‐Liss, Inc.
Shh‐Bmp2 signaling module and the evolutionary origin and diversification of feathers
Authors: Harris Matthew P. , Fallon John F. , Prum Richard O.
Published: October 2002

To examine the role of development in the origin of evolutionary novelties, we investigated the developmental mechanisms involved in the formation of a complex morphological novelty—branched feathers. We demonstrate that the anterior‐posterior expression polarity of Sonic hedgehog (Shh) and Bone morphogenetic protein 2 (Bmp2) in the primordia of feathers, avian scales, and alligator scales is conserved and phylogenetically primitive to archosaurian integumentary appendages. In feather development, derived patterns of Shh‐Bmp2 signaling are associated with the development of evolutionarily novel feather structures. Longitudinal Shh‐Bmp2 expression domains in the marginal plate epithelium between barb ridges provide a prepattern of the barbs and rachis. Thus, control of Shh‐Bmp2 signaling is a fundamental component of the mechanism determining feather form (i.e., plumulaceous vs. pennaceous structure). We show that Shh signaling is necessary for the formation and proper differentiation of a barb ridge and that it is mediated by Bmp signaling. BMP signaling is necessary and sufficient to negatively regulate Shh expression within forming feather germs and this epistatic relationship is conserved in scale morphogenesis. Ectopic SHH and BMP2 signaling leads to opposing effects on proliferation and differentiation within the feather germ, suggesting that the integrative signaling between Shh and Bmp2 is a means to regulate controlled growth and differentiation of forming skin appendages. We conclude that Shh and Bmp signaling is necessary for the formation of barb ridges in feathers and that Shh and Bmp2 signaling constitutes a functionally conserved developmental signaling module in archosaur epidermal appendage development. We propose a model in which branched feather form evolved by repeated, evolutionary re‐utilization of a Shh‐Bmp2 signaling module in new developmental contexts. Feather animation Quicktime movies can be viewed at http://fallon.anatomy.wisc.edu/feather.html. J. Exp. Zool. (Mol. Dev. Evol.) 294:160–176, 2002. © 2002 Wiley‐Liss, Inc.
Generation of stable retrovirus packaging cell lines after transduction with herpes simplex virus hybrid amplicon vectors‡
Authors: Sena‐Esteves Miguel , Hampl Jürgen A. , Camp Sara M. , Breakefield Xandra O.
Published: October 2002

Background

A number of properties have relegated the use of Moloney murine leukemia virus (Mo‐MLV)‐based retrovirus vectors primarily to ex vivo protocols. Direct implantation of retrovirus producer cells can bypass some of the limitations, and in situ vector production may result in a large number of gene transfer events. However, the fibroblast nature of most retrovirus packaging cells does not provide for an effective distribution of vector producing foci in vivo, especially in the brain. Effective development of new retrovirus producer cells with enhanced biologic properties may require the testing of a large number of different cell types, and a quick and efficient method to generate them is needed.

Methods

Moloney murine leukemia virus (Mo‐MLV) gag‐pol and env genes and retrovirus vector sequences carrying lacZ were cloned into different minimal HSV/AAV hybrid amplicons. Helper virus‐free amplicon vectors were used to co‐infect glioma cells in culture. Titers and stability of retrovirus vector production were assessed.

Results

Simultaneous infection of two glioma lines, Gli‐36 (human) and J3T (dog), with both types of amplicon vectors, generated stable packaging populations that produced retrovirus titers of 0.5–1.2×105 and 3.1–7.1×103 tu/ml, respectively. Alternatively, when cells were first infected with retrovirus vectors followed by infection with HyRMOVAmpho amplicon vector, stable retrovirus packaging populations were obtained from Gli‐36 and J3T cells producing retrovirus titers comparable to those obtained with a traditional retrovirus packaging cell line, ΨCRIPlacZ.

Conclusions

This amplicon vector system should facilitate generation of new types of retrovirus producer cells. Conversion of cells with migratory or tumor/tissue homing properties could result in expansion of the spatial distribution or targeting capacity, respectively, of gene delivery by retrovirus vectors in vivo. Copyright © 2002 John Wiley & Sons, Ltd.
Social funds, sustainability and institutional development impacts: findings from an OED Review
Authors: Carvalho Soniya , Perkins Gillian , White Howard
Published: October 2002

This paper, based on a recent OED review of World Bank social fund projects, presents findings relating to two aspects of social fund performance that have been relatively under‐researched in the social funds literature—the sustainability of benefits and the institutional development impacts. On sustainability, the review found that social fund facilities generally had staffing and equipment levels better or equal to those in comparator facilities although both types of facilities suffered from shortages. While there has been a learning curve, deficiencies were found in the requirements for ongoing operations and maintenance over the operational life of the investments. On institutional development impact, the review found that social fund agencies have developed capacity as effective and innovative organizations. Wider impacts on existing institutions, both positive and negative, need greater attention. Copyright © 2002 John Wiley & Sons, Ltd.
The impact of market reforms on the Senegalese peanut economy
Authors: Hathie Ibrahima , Lopez Rigoberto A.
Published: October 2002

This article assesses the welfare impacts of structural adjustment‐induced peanut market reforms in Senegal. In the pre‐reform period, by keeping peanut prices low, price regulation favoured urban dwellers and processors to the detriment of farmers, although the latter benefited from subsidized credit and inputs. With the reforms, peanut prices increased but the ensuing benefits to farmers were outweighed by higher production costs. Consumers gained due to access to cheaper, imported vegetable oil and processors lost due to excess capacity from lower peanut production. Overall, social welfare decreased illustrating that unfettered market reforms can be detrimental when supportive market institutions are eliminated without addressing alternatives. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis of 15N and 13C selectively labeled anandamide
Authors: Xie Xiang‐Qun , Yang Hongqin , Choi Greg , Lin Sunyuan , Makriyannis Alexandros
Published: October 2002

Anandamide (Figure 1a) (arachidonyl ethanolamide, AEA), (5Z,8Z,11Z,14Z)‐N‐(2‐hydroxyethyl)‐5,8,11,14‐Eicosatetraenamide, is an endogenous cannabinoid ligand possessing important biological activity. The conformation of AEA in its native receptor binding environment is particularly of interest for pharmaceutical research and biochemistry in general. Here we report a novel synthetic pathway, which selectively introduces 15N and 13C isotopes into the anandamide molecule. This isotopically labeled AEA can be studied conformationally in its native binding condition via solid state NMR. These synthetic procedures can also be adapted to produce radioactive ligands for receptor binding assays and other structural studies. Copyright © 2002 John Wiley & Sons, Ltd.
Spoiled gradient‐echo as an arterial spin tagging technique for quick evaluation of local perfusion
Authors: Chai Jyh‐Wen , Chen Jeon‐Hor , Kao Yi‐Hsuan , Liao Jan‐Ray , Chen Clayton Chi‐Chang , Lee San‐Kan , Chu Woei Chyn
Published: October 2002

Purpose

To introduce a simple gradient‐echo arterial spin tagging (GREAST) technique available for most commercial magnetic resonance (MR) systems, for a quick evaluation of tissue perfusion.

Materials and Methods

The GREAST technique uses a combination of a short TR spoiled gradient‐echo (SPGR) sequence with a selective presaturation radio frequency (RF) pulse that allows acquiring each tagged and control image within 10–20 seconds. The phantom and human studies were performed for evaluating the feasibility in measurement of local perfusion and the efficacy in alleviation of the asymmetric magnetization transfer (MT) and slice profile effects.

Results

Results show a good linear relationship between the signal attenuation caused by the presaturation pulse and flow rates in the phantom experiment and effective alleviation of the asymmetric MT and slice profile effects for various orientations of imaging slices. Human studies showed good perfusion results in brain imaging. Perfusion imaging on the liver and kidney were also conducted. The results could be significantly improved by effectively lessening motion‐related artifacts.

Conclusion

The GREAST technique is simple, easy to use, and applicable to examine local perfusion of the brain and other organs in the trunk. J. Magn. Reson. Imaging 2002;16:51–59. © 2002 Wiley‐Liss, Inc.
MR imaging of the forefoot under weight‐bearing conditions: Position‐related changes of the neurovascular bundles and the metatarsal heads in asymptomatic volunteers
Authors: Weishaupt Dominik , Treiber Karl , Jacob Hilaire A.C. , Kundert Hans‐Peter , Hodler Juerg , Marincek Borut , Zanetti Marco
Published: October 2002

Purpose

To assess practicability of weight‐bearing magnetic resonance (MR) imaging of the forefoot, and to demonstrate position‐related changes of the neurovascular bundles and the metatarsal heads in asymptomatic volunteers.

Materials and Methods

With an open‐configuration MR system, 32 feet of 32 asymptomatic individuals aged 20–60 years were studied in supine and weight‐bearing body positions. Transverse T1‐weighted spin‐echo MR images were performed. MR images were evaluated qualitatively with regard to image quality, visibility, and position‐dependent changes of the neurovascular bundle. In addition, the position of the metatarsal heads was analyzed quantitatively.

Results

Weight‐bearing MR imaging was feasible in all 32 feet. Quality of MR images obtained in the weight‐bearing position was superior to that obtained in the supine position (P < 0.05). A change in the position of the neurovascular bundle from below a virtual line paralleling the plantar cortical line to above this line was present in 50 of 61 instances (82%) between the supine and the weight‐bearing positions. When changing from the supine to the weight‐bearing position, there was a significant decrease in the distance between the plantar skin and the metatarsal heads for the second (mean 4.5 mm), third (mean 4.4 mm), and fourth metatarsal heads (mean 3.7 mm) (P < 0.0001). However, the difference for the first (mean 0.5 mm) and fifth (mean 0.9 mm) metatarsal heads was not significant.

Conclusion

Weight‐bearing MR imaging of the forefoot is feasible using an open‐configuration MR system and demonstrates position‐related changes of the neurovascular bundles relative to the metatarsal heads, as well as position‐related changes of the metatarsal heads themselves. J. Magn. Reson. Imaging 2002;16:75–84. © 2002 Wiley‐Liss, Inc.
In vivo magnetic resonance imaging of the human cervical spinal cord at 3 Tesla
Authors: Korzan Jeffrey R. , Gorassini Monica , Emery Derek , Taher Zaki A. , Beaulieu Christian
Published: October 2002

Purpose

To demonstrate the feasibility of obtaining high‐quality magnetic resonance (MR) images of the human cervical spinal cord in vivo at a magnetic field strength of 3 T and to optimize the signal contrast between gray matter, white matter, and cerebrospinal fluid (CSF) on 2D gradient recalled echo (GRE) images of the cervical spinal cord.

Materials and Methods

Using a custom‐built, anatomically molded radio frequency (RF) surface coil, the repetition time and flip angle of a 2D GRE sequence were systematically varied in five volunteers to assess tissue contrast in the cervical spinal cord.

Results

The 2D GRE parameters for an optimal balance between gray‐white matter and CSF‐white matter contrast at 3 T were determined to be a time‐to‐repetition (TR) of 2000 msec and a flip angle of 45°, with the constant short time‐to‐echo (TE) of 12 msec used in this study. Excellent tissue contrast and visualization of the internal anatomy of the spinal cord was demonstrated reproducibly in eight subjects using these optimal parameters.

Conclusion

This study demonstrates that imaging the cervical spinal cord and delineating internal spinal cord structures such as gray and white matter is feasible at 3 T. J. Magn. Reson. Imaging 2002;16:21–27. © 2002 Wiley‐Liss, Inc.
Proton MRS in Kennedy disease: Absolute metabolite and macromolecular concentrations
Authors: Mader Irina , Karitzky Jochen , Klose Uwe , Seeger Uwe , Sperfeld Anne , Naegele Thomas , Schick Fritz , Ludolph Albert , Grodd Wolfgang
Published: October 2002

Purpose

To investigate whether glutamine and glutamate (Glx) were elevated in Kennedy Disease (KD), and whether pathological proteins were spectroscopically visible as altered macromolecular (MM) resonances.

Materials and Methods

Ten patients with KD and twelve healthy volunteers were investigated using a stimulated echo acquisition mode (STEAM) spectroscopy sequence with metabolite‐nulling.

Results

The concentrations of Glx remained unchanged in KD. An increased myo‐inositol (Ins), and elevated MM at 0.9 ppm were found within the motor area. The N‐acetyl‐aspartate (NAA)/creatine (Cr) ratio was negatively correlated to the number of cytosine adenosine guanine (CAG) repeats in the motor area.

Conclusion

The elevated MM at 0.9 ppm may be attributed to a pathologically altered protein in KD. Additionally, the changes of Ins point to a clinically unexpected involvement of the motor cortex. The correlation of NAA/Cr with the number of CAG repeats indicates a link between metabolites and genetic failure. J. Magn. Reson. Imaging 2002;16:160–167. © 2002 Wiley‐Liss, Inc.
FAIR and dynamic susceptibility contrast‐enhanced perfusion imaging in healthy subjects and stroke patients
Authors: Hunsche Stefan , Sauner Dieter , Schreiber Wolfgang G. , Oelkers Peter , Stoeter Peter
Published: October 2002

Purpose

To compare dynamic susceptibility contrast‐enhanced magnetic resonance imaging (DSC‐MRI) and the flow‐sensitive alternating inversion recovery (FAIR) technique for measuring brain perfusion.

Materials and Methods

We investigated 12 patients with acute stroke, and 10 healthy volunteers with FAIR and DSC maps of regional cerebral blood volume (rCBV), mean transit time (MTT), and regional cerebral blood flow (rCBF).

Results

In volunteers good gray/white‐matter contrast was observed in FAIR, rCBF, and rCBV maps. Regions with high signal intensities in FAIR matched well with high values of rCBV and rCBF. In ischemic stroke patients a high correlation (r = 0.78) of the ipsi‐ to contralateral signal intensity ratios in FAIR and rCBF was observed in areas with perfusion abnormalities. In contrast, FAIR and rCBV (r = 0.50), and FAIR and MTT (r = −0.22) correlated only modestly. Furthermore, FAIR and rCBF demonstrated similar sizes of perfusion abnormality.

Conclusion

This study demonstrates for the first time that FAIR and rCBF depict similar relations of perfusion in ischemic stroke patients and healthy subjects. J. Magn. Reson. Imaging 2002;16:137–146. © 2002 Wiley‐Liss, Inc.
Application of 1‐alkylamines to a liquid chromatographic/turbo ionspray tandem mass spectrometric method for quantifying metabolites of a new bone anabolic agent, TAK‐778, in human serum
Authors: Teshima Koichiro , Kondo Takahiro , Maeda Chie , Oda Tsuneo , Hagimoto Toshiaki , Tsukuda Ryoichi , Yoshimura Yoshinobu
Published: October 2002

We investigated the application of alkylamines, as additives to the mobile phase, to a quantification method for the metabolites, M‐III and M‐IV, of TAK‐778, which is a new bone anabolic agent, in human serum using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Prior to setting up the analytical method, we found that 1‐alkylamines co‐existing with M‐III and M‐IV in the turbo ionsprayed solution formed 1‐alkylammonium adduct molecules of these metabolites during the ionization process, and the abundance of the adduct ions was considerably higher than that of protonated molecules ([M + H]+s) of these metabolites. Based on these findings, we investigated a variety of 1‐alkylamines and their spiked concentrations in the mobile phase for LC/MS/MS analysis to obtain higher sensitivities for the quantification of these metabolites. After these examinations, we found that 1‐hexylamine at a final concentration of 0.05 mmol l−1 was the most suitable additive for the mobile phase, and set the selected reaction monitoring (SRM) ions for the 1‐hexylammonium adduct molecule and [M + H]+, allowing about a fivefold gain in the SRM chromatographic peak compared with that without 1‐hexylamine. The adduct ion was considered to be formed by interaction between the amino group of 1‐hexylamine and the phosphoryl group of M‐III and M‐IV. The internal standard (I.S.) used was deuterated M‐III for each metabolite. The analytes and I.S. were extracted with diethyl ether from serum samples at neutral pH and injected into the LC/MS/MS system with a turbo ionspray interface. The limit of quantification for both analytes was 0.5 ng ml−1 when 0.1 ml of serum was used, and the calibration curves were linear in the range 0.5–100 ng ml−1. The method was precise; the intra‐ and inter‐day precisions of the method were not more than 5.6%. The accuracy of the method was good, with deviations between added and calculated concentrations of M‐III and M‐IV being typically within 16.6%. This method provided reliable pharmacokinetic data for M‐III and M‐IV after the intramuscular administration of TAK‐778 sustained‐release formulation in humans. Copyright © 2002 John Wiley & Sons, Ltd.
Hepatitis B vaccination: Risk‐benefit profile and the role of systematic reviews in the assessment of causality of adverse events following immunisation
Authors: Jefferson Tom , Traversa Giuseppe
Published: October 2002

Since the early 1990s, several cases of demyelinating diseases were reported in France in association with the vaccination against hepatitis B. A large scientific, regulatory, and public debate took place to reassure the growing concern of the population. The objective of this paper is to examine the decision process undertaken both in France and in Italy; to outline the main findings of the studies conducted before and after the French decision to suspend the vaccination campaign among adolescents; and to describe the contribution of systematic review and causality criteria in the evaluation of the risk‐benefit profile of vaccines. Even on the basis of the early findings, which appeared to be compatible with a low increase in the risk associated with the vaccination, it was apparent that the risk‐benefit profile was unchanged for newborns, and was essentially unchanged for adolescents and for high‐risk adults. The availability of subsequent negative association studies provided further reassurance. It is essential to rely on well‐conducted systematic reviews to produce valid and reliable estimates of the risk‐benefit profile. J. Med. Virol. 67:451–453, 2002. © 2002 Wiley‐Liss, Inc.
Hepatitis B virus transmission in Brazilian hemodialysis units: Serological and molecular follow‐up
Authors: Teles Sheila A. , Martins Regina M.B. , Gomes Selma A. , Gaspar Ana M.C. , Araujo Natália M. , Souza Karla P. , Carneiro Megmar A.S. , Yoshida Clara F.T.
Published: October 2002

A serological and molecular study of hepatitis B virus (HBV) infection was carried out in dialysis units in Central Brazil. Between 1995 and 1999, serum samples from all HBsAg‐positive hemodialysis patients (n = 43) were tested for HBeAg/anti‐HBe and subtyping by monoclonal ELISA. HBV DNA was detected by PCR and positive samples were genotyped by restriction fragment polymorphism pattern (RFLP) methodology. TheHBsAg prevalence declined in this population during the survey period (12–5.8%). HBeAg and anti‐HBe were detected in 23 (53.5%) and 18 (41.9%) sera, respectively. Thirty‐six samples could be HBsAg subtyped: 21 were subtype ayw3, 14 belonged to adw2 and one was identified as adw4. HBV DNA was present in 30 serum samples. Of these, 20 (66.7%) were genotype D, 9 (30%) genotype A, and 1 (3.3%) genotype F. In addition, the RFLP pattern could be determined in samples from 18/20 genotype D patients: D3 (10 strains), D7 (7 strains) and D4 (1 strain); from 8/9 genotype A patients: A1 (6 strains) and A3 (2 strains); and from the patient infected with genotype F: F1. Patterns D3 and D7 were associated closely with HBV infection in the two largest hemodialysis units studied. These findings confirm the value of the RFLP method as an effective molecular epidemiological tool for elucidating HBV transmission in hemodialysis units. J. Med. Virol. 68:41–49, 2002. © 2002 Wiley‐Liss, Inc.
Herpes simplex virus type 1 variants arising after selection with an antiviral carrageenan: Lack of correlation between drug susceptibility and syn phenotype
Authors: Carlucci M.J. , Scolaro L.A. , Damonte E.B.
Published: October 2002

Natural carrageenans of diverse structural types isolated from the red seaweed Gigartina skottsbergii were recently identified as potent and selective inhibitors of herpes simplex virus types 1 and 2 (HSV‐1 and ‐2). The μ/ν‐carrageenan 1C3 was tested in vitro for its ability to select resistant variants. After serial passages of HSV‐1 strain F in Vero cells in the presence of increasing concentrations of 1C3, viruses emerged that were approximately 2‐ to 10‐fold more resistant to 1C3 inhibition than parental virus; these viruses formed large plaques with an altered syncytial phenotype (1C3‐syn). Plaque‐purified syncytial variants isolated from passages 13 and 14 have shown variable levels of resistance to 1C3, as well as to the other antiviral carrageenans isolated from G. skottsbergii and to other sulfated polysaccharides with known antiviral activity, such as heparin and dextran sulfate 8000, but all the clones were susceptible to acyclovir. The syn phenotype was not related to polysaccharide resistance. All the 1C3‐syn variants formed large syncytia in Vero and CV‐1 cells but did not induce fusion in other cell types. The growth efficiency in Vero cells, as well as the virulence for mice by intracerebral or intraperitoneal inoculation of 1C3‐syn variants, showed no significant alterations in comparison with the parental virus. The syncytial properties were not affected by cyclosporine or melittin, suggesting that an alteration on glycoprotein gB could be responsible for the syn phenotype induced by 1C3. J. Med. Virol. 68:92–98, 2002. © 2002 Wiley‐Liss, Inc.
Kaposi's sarcoma herpesvirus and HIV‐1 seroprevalences in prostitutes in Djibouti
Authors: Marcelin Anne‐Geneviève , Grandadam Marc , Flandre Philippe , Nicand Elisabeth , Milliancourt Catherine , Koeck Jean‐Louis , Philippon Michel , Teyssou Remy , Agut Henri , Dupin Nicolas , Calvez Vincent
Published: October 2002

Kaposi's sarcoma herpesvirus (KSHV) is linked causally to Kaposi's sarcoma. Epidemiological studies have shown that KSHV transmission can occur during sex among homosexual men, but heterosexual transmission seems to be very rare in KSHV low prevalence countries. A seroepidemiological study was conducted to determine whether KSHV is transmitted sexually between heterosexuals in an endemic country. Sera from 282 subjects of African origin living in Djibouti were tested for antibodies to KSHV and HIV‐1. Among the 282 individuals, 43 were female prostitutes working in the streets (group 1), 123 were female prostitutes working in luxury bars (group 2), 41 were non‐prostitute females (group 3), and 75 were non‐prostitute males (group 4). KSHV seroprevalence was 26, 20, 17, and 36% in groups 1, 2, 3, and 4, respectively. The seroprevalence of KSHV is not different between street or bar prostitutes and non‐prostitute females (OR = 1.67; P = 0.34 and OR = 1.18; P = 0.73). These results suggest that in this endemic country commercial sex work does not seem to be a risk factor for KSHV infection and provides evidence against heterosexual transmission of KSHV in the female population studied. J. Med. Virol. 68: 164–167, 2002. © 2002 Wiley‐Liss, Inc.
Inhibition of clinical isolates of human cytomegalovirus and varicella zoster virus by PNU‐183792, a 4‐oxo‐dihydroquinoline
Authors: Knechtel Mary L. , Huang Audris , Vaillancourt Valerie A. , Brideau Roger J.
Published: October 2002

The susceptibility of human cytomegalovirus (CMV) and varicella zoster virus (VZV) clinical isolates to PNU‐183792, a 4‐oxo‐dihydroquinoline, was examined. The antiviral potency of PNU‐183792, a non‐nucleoside inhibitor, was compared to the licensed nucleoside inhibitors ganciclovir and acyclovir using plaque reduction and virus yield reduction assays. PNU‐183792 was as potent against CMV as ganciclovir and was superior in potency to acyclovir against VZV. PNU‐183792 represents a new class of non‐nucleoside inhibitors of human herpesviruses. J. Med. Virol. 68: 234–236, 2002. © 2002 Wiley‐Liss, Inc.
Cellular glycosaminoglycans and low density lipoprotein receptor are involved in hepatitis C virus adsorption
Authors: Germi Raphaële , Crance Jean‐Marc , Garin Daniel , Guimet Josette , Lortat‐Jacob Hugues , Ruigrok Rob W.H. , Zarski Jean‐Pierre , Drouet Emmanuel
Published: October 2002

The initial binding of Hepatitis C virus (HCV) to the cell membrane is a critical determinant of pathogenesis. Two putative HCV receptors have been identified, CD81 and low‐density lipoprotein receptor (LDLr). CD81 interacts in vitro with the HCV E2 envelope glycoprotein, and LDLr interacts with HCV present in human plasma. In order to characterize these potential receptors for HCV, virus from plasma, able to replicate in cell culture, was inoculated on Vero cells or human hepatocarcinoma cells. HCV adsorption was assessed by quantitating cell‐associated viral RNA by a real‐time RT‐PCR method. Anti‐LDLr antibody, low and very low density lipoproteins inhibited significantly HCV adsorption, confirming the role of LDLr as HCV receptor. Only one out of the two anti‐CD81 antibodies used in this study led to a partial inhibition of HCV binding. This study also highlights a role for glycosaminoglycans (GAGs) in HCV adsorption: treatment of virus with heparin led to 70% inhibition of attachment, as did desulfation of cellular GAGs. Treatment of Vero cells with heparin‐lyase significantly inhibited virus attachment but by only 30%. These results demonstrate the complexity of the HCV binding step in which LDLr interacts strongly with HCV, whereas the interaction of HCV with GAGs and particularly with CD81 seem to be more moderate. J. Med. Virol. 68:206–215, 2002. © 2002 Wiley‐Liss, Inc.
Effects of gag mutations on human immunodeficiency virus type 1 particle assembly, processing, and cyclophilin a incorporation
Authors: Chiu Hsu‐Chen , Wang Fu‐Der , Yao Szu‐Yung , Wang Chin‐Tien
Published: October 2002

A series of human immunodeficiency virus (HIV) mutants was constructed either by deletion or by linker insertion at various regions in the gag coding sequences. The ability of each mutant to assemble virus particles and to process them proteolytically, as well as incorporate cyclophilin A, was analyzed by Western immunoblot. This investigation indicated that most of the gag mutants were assembled and released at a level comparable to that of wild‐type virus. In an assay involving a single cycle of infection, mutants containing significant levels of cyclophilin A showed less in trans interference effects on wild‐type infectivity than did cyclophilin A‐deficient mutants. Mutations in the N‐terminal two‐thirds of capsid protein severely disrupted cyclophilin A incorporation, but they affected virus processing only slightly to moderately. Virions released from cyclosporine‐treated cells were processed, as well as virions made by the mock‐treated cells. Also, protease inhibitor treatment had no detectable effect on the cyclophilin A incorporation. These results indicate that cyclophilin A incorporation is not required for virus particle processing and that virus processing does not affect cyclophilin A incorporation. J. Med. Virol. 68: 156–163, 2002. © 2002 Wiley‐Liss, Inc.
Genotypic and phenotypic analysis of the env gene from South African HIV‐1 subtype B and C isolates
Authors: Treurnicht Florette K. , Smith Tracey‐Lee , Engelbrecht Susan , Claassen Matilda , Robson Brenda A. , Zeier Michelle , Rensburg Estrelita Janse van
Published: October 2002

The objective of the study was to assess the genotypic and phenotypic properties of 18 viral strains from human immunodeficiency virus‐1 (HIV‐1) positive patients and to identify subtype C isolates for vaccine design strategies. All the isolates were non–syncytium‐inducing (NSI) in both the primary and MT‐2 cell cultures. The amino acid charge of the V3 loop correlated with the NSI phenotype of the strains. The V3 competitive peptide enzyme immunoassay and DNA sequencing of the partial gp120 region gave concordant results on the 15 subtype C strains, whereas the three B genotypes gave a positive to B, a nonreactive to B, and a dual reaction to the B–D peptides, respectively. Sixteen of the isolates used only CCR5 as coreceptor whereas two isolates made use of additional coreceptors including CXCR4. In summary, all our subtype C isolates are NSI phenotypically and almost all of them use CCR5 exclusively as their coreceptor. J. Med. Virol. 68: 141–146, 2002. © 2002 Wiley‐Liss, Inc.
Wave speeds for a TLM model of moving media
Authors: O'Connor William J.
Published: October 2002

In a companion paper, a transmission line matrix (TLM) scheme was presented for the solution of the 1‐D equation of waves in moving media, ytt+αyxt+βyxx=0, describing the superposition of two waves with direction‐dependent speeds. The TLM model achieved controlled, direction‐dependent wave‐speed bias by means of supplementary link lines with notional ‘diodes’. Expressions for wave speed, presented without proof, were verified. Here a proof is presented using a new, time‐domain approach. The apparent (direction‐dependent) inductance and capacitance as seen by a single wave are first established in a generalized way from the TLM algorithm, from which two wave speeds and impedances are then derived. Copyright © 2002 John Wiley & Sons, Ltd.
Comparative analysis of Schwann cell lines as model systems for myelin gene transcription studies
Authors: Hai Mehreen , Muja Naser , DeVries George H. , Quarles Richard H. , Patel Pragna I.
Published: October 2002

Primary and immortalized cultured Schwann cells are commonly utilized in analyses of myelin gene promoters, but few lines are well‐characterized in terms of their endogenous expression of myelin genes. This is particularly significant in that cultured Schwann cells typically do not express myelin genes at levels comparable to those observed in vivo. In this study, the steady‐state levels of mRNA and protein for five Schwann cell markers (PMP22, P0, MBP, MAG, and LNGF‐R) were assessed in primary Schwann cells and six representative Schwann cell lines (RT4‐D6P2T, JS‐1, RSC96, R3, S16, and S16Y). RT4‐D6P2T and S16 cells were the most similar to myelinating Schwann cells based on their comparatively high expression of PMP22 and P0 mRNA. Both RT4‐D6P2T and S16 also expressed P0 protein. In addition, the previously reported P1‐A positive regulatory region from the myelination‐specific PMP22 promoter demonstrated significant activity in both these cell lines. However, nuclear proteins that interacted with P1‐A were different in extracts prepared from RT4‐D6P2T and S16 cells. Primary Schwann cells expressed myelin proteins at levels that were equal or less than those observed with the RT4‐D6P2T and S16 lines, indicating that primary Schwann cells are not necessarily better than immortalized Schwann cells as model systems for the study of myelin gene regulation. The data presented here demonstrate that cultured Schwann cells used to study myelin gene promoters have to be carefully selected on the basis of the endogenous level of expression of the myelin gene under study. © 2002 Wiley‐Liss, Inc.
So, how do people really use their handheld devices? An interactive study of wireless technology use
Authors: Schlosser Francine K.
Published: October 2002

Using a symbolic interactionist methodology, the diverse meanings assigned by employees to wireless handheld technology are investigated. Interviews were conducted with 11 individuals representing three organizations in the public and private sector enhancing our understanding of technology use within an organizational context. Wireless technology practices are examined as they relate to aspects of self‐identity, that is, the imaged self, the relational self, the integrated self and the isolated self. Individuals were able to fit the technology into their work and personal roles, and at the same time, adjusted these roles to fit new expectations arising from the technology. Innovative ways of using the technology were shaped by individual needs as users adapted their message contexts, social etiquette, self‐impressions, and ways of doing business. A need to self‐regulate emerged with high expectations of availability and the blurring of multiple work and personal roles. Copyright © 2002 John Wiley & Sons, Ltd.
The effects of quality improvement practices on team effectiveness: a mediational model
Authors: Lemieux‐Charles Louise , Murray Michael , Ross Baker G. , Barnsley Jan , Tasa Kevin , Ibrahim Salahadin A.
Published: October 2002

Researchers have been challenged to specify the processes that quality improvement (QI) practices could be expected to generate and to explain how they might contribute to organizational effectiveness. This research article meets that challenge through a study of 97 teams in the health care field. The authors developed a ‘Quality Improvement Practices Index’ and showed that QI practices could be differentiated from traditional team‐level variables, and that such practices affect both directly and indirectly (through team‐level variables) team effectiveness. Two models were tested using structural equation modelling. It was found that the perceptions of the impact of QI practices on team effectiveness varied depending on who was assessing the team's performance—members of the team or managers who were external to the team but responsible for the team's performance. The authors discuss the implications of these results both for researchers and practitioners. Copyright © 2002 John Wiley & Sons, Ltd.