bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of osteoblast‐like cell responses to calcium silicate and tricalcium phosphate ceramics in vitro
Authors: Ni Siyu , Chang Jiang , Chou Lee , Zhai Wanyin
Published: June 2006

Calcium silicate ceramics have been proposed as new bone repair biomaterials, since they have proved to be bioactive, degradable, and biocompatible. β‐tricalcium phosphate ceramic is a well‐known degradable material for bone repair. This study compared the effects of CaSiO3 (α‐, and β‐CaSiO3) and β‐Ca3(PO4)2 (β‐TCP) ceramics on the early stages of rat osteoblast‐like cell attachment, proliferation, and differentiation. Osteoblast‐like cells were cultured directly on CaSiO3 (α‐, and β‐CaSiO3) and β‐TCP ceramics. Attachment of a greater number of cells was observed on CaSiO3 (α‐, and β‐CaSiO3) ceramics compared with β‐TCP ceramics after incubation for 6 h. SEM observations showed an intimate contact between cells and the substrates, significant cells adhesion, and that the cells spread and grew on the surfaces of all the materials. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of the cells on the CaSiO3 (α‐, and β‐CaSiO3) ceramics were improved when compared with the β‐TCP ceramics. In the presence of CaSiO3, elevated levels of calcium and silicon in the culture medium were observed throughout the 7‐day culture period. In conclusion, the results of the present study revealed that CaSiO3 ceramics showed greater ability to support cell attachment, proliferation, and differentiation than β‐TCP ceramic. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Development of a polymeric matrix metalloproteinase inhibitor as a bioactive stent coating material for prevention of restenosis
Authors: Nakayama Yasuhide , Masuda Takeshi
Published: June 2006

Drug‐eluting stents have been developed to prevent restenosis derived from excessive growth of smooth muscle cells (SMCs) after stenting. In almost every case, however, less‐ or non–biocompatible polymers were selected for the platform material for impregnating drugs on the stent strut. Consideration was given principally to the physical properties of the polymers, such as their adhesion to the strut and the drug dispersibility in the polymeric matrix. In this study, we designed a matrix metalloproteinase inhibitor (MMPI)‐derivatized hydrophobic polymer (PMMPI) for use as a bioactive material for stent coating. This was a copolymer of n‐butylmethacrylate and a vinyl monomer of synthetic MMPI (N‐Hydroxy‐5‐carboxyethylcarbonyloxy‐2(S)‐methy‐4(S)‐(4‐phenoxybenzoyl)amino‐pentanamide: ONO‐M11–335) with a molecular weight of about 32,000 and MMPI content of 45 per molecule. The precursor of the MMPI monomer produced significant activity in temporally inhibiting SMC proliferation without any cellular damage. After coating with the PMMPI, adhesion and proliferation of SMCs were manifestly prevented even when a small amount of MMPI was released from the polymer. The MMPI‐immobilized surface may thus be effective for inhibiting both adhesion and proliferation of SMCs, which is the first step toward in vivo experimentation. It is very much expected that coating stent struts with PMMPI containing an appropriate combination of impregnated drugs will provide a powerful tool for prevention of restenosis with little cytotoxicity. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Modulation of peritendinous adhesion formation by alginate solution in a rabbit flexor tendon model
Authors: Namba Jiro , Shimada Kozo , Saito Masanobu , Murase Tsuyoshi , Yamada Hideaki , Yoshikawa Hideki
Published: June 2006

To examine the antiadhesive effect of an alginate solution following tendon surgery, unilateral subtotal laceration of the flexor digitorum communis tendon was created in one hind limb while the other side was left intact in 32 Japanese white rabbits. The lesion was coated with alginate solution in 16 animals and not coated in the other 16. Degree of adhesion formation was assessed histologically and biomechanically by measuring the flexion angle of the first toe when the flexor digitorum tendon was pulled with a specified force at 4 weeks postoperatively. When compared with the control group, the alginate‐treated group demonstrated significantly greater toe flexion, with less scar tissue formation at the repair site. Histologically, complete tendon healing with longitudinal remodeling of collagen fibers was observed in the alginate‐treated group, while a random pattern of fibers was observed in the control group. Reduction in adhesion formation using alginate solution represents a novel strategy for the management of tendon injury and repair in the clinical setting. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Bonding characteristics of newly developed all‐in‐one adhesives
Authors: Sidhu S. K. , Omata Y. , Tanaka T. , Koshiro K. , Spreafico D. , Semeraro S. , Mezzanzanica D. , Sano H.
Published: June 2006

This study evaluated the microtensile bond strength and the interfacial morphology of newer adhesives. The occlusal surfaces of extracted teeth were ground flat for random allocation to four equal groups. Resin composite was bonded to each surface using either Clearfil SE Bond [SEB], Clearfil Protect Bond [PB], G‐Bond [GB], or an experimental adhesive, SSB‐200 [SSB]. After storage for 24 h in water at 37°C, they were sectioned into beams (cross‐sectional area 1 mm2) for microtensile bond strength testing (μTBS) at a crosshead speed of 1 mm/min. The load at failure of each was recorded; the data were analyzed by one‐way ANOVA and Games Howell tests. The surfaces of the fractured specimens were observed using SEM. For the ultra‐morphology of the interface, the occlusal surfaces of four more teeth were prepared as before and a thin layer of flowable resin composite was bonded to each surface using one of the four adhesives.The mean μTBS ranged from 39.68 MPa (GB) to 64.97 MPa (SEB). There were no statistical differences between SEB and SSB, or between PB and GB (p > 0.05). The μTBS of SEB and SSB were significantly greater than that of PB and GB (p < 0.05). SEMs of the fractured surfaces revealed a mixed (cohesive/interfacial) failure. TEM examination highlighted differences in the hybrid layer; SEB had a thicker layer than the others. In conclusion, the newer all‐in‐one adhesives produced a thin hybrid layer but varied in their bond strengths. The 2‐step self‐etching adhesives do not necessarily produce higher bond strengths than that of the all‐in‐one systems. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
A new rhenanite (β‐NaCaPO4) and hydroxyapatite biphasic biomaterial for skeletal repair
Authors: Jalota Sahil , Bhaduri Sarit B. , Tas A. Cuneyt
Published: June 2006

Biphasic β‐rhenanite (β‐NaCaPO4)–hydroxyapatite (Ca10(PO4)6(OH)2) biomaterials were prepared by using a one‐pot, solution‐based synthesis procedure at the physiological pH of 7.4, followed by low‐temperature (300–600°C) calcination in air for 6 h. Calcination was for the sole purpose of crystallization. An aqueous solution of Ca(NO3)2· 4H2O was rapidly added to a solution of Na2HPO4 and NaHCO3, followed by immediate removal of gel‐like, poorly‐crystallized precursor precipitates from the mother liquors of pH 7.4. Freeze‐dried precursors were found to be nanosize with an average particle size of 45 nm and a surface area of 128 m2/g. Upon calcination in air, precursor powders crystallized into biphasic (60% HA–40% rhenanite) biomaterials, while retaining their submicron particle sizes and high surface areas. β‐rhenanite is a high solubility sodium calcium phosphate phase. Samples were characterized by XRD, FTIR, SEM, TEM, ICP‐AES, TG, DTA, DSC, and surface area measurements. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Gene therapy for lung cancer
Authors: Toloza Eric M. , Morse Michael A. , Lyerly H. Kim
Published: June 2006

Lung cancer patients suffer a 15% overall survival despite advances in chemotherapy, radiation therapy, and surgery. This unacceptably low survival rate is due to the usual finding of advanced disease at diagnosis. However, multimodality strategies using conventional therapies only minimally improve survival rates even in early stages of lung cancer. Attempts to improve survival in advanced disease using various combinations of platinum‐based chemotherapy have demonstrated that no regimen is superior, suggesting a therapeutic plateau and the need for novel, more specific, and less toxic therapeutic strategies. Over the past three decades, the genetic etiology of cancer has been gradually delineated, albeit not yet completely. Understanding the molecular events that occur during the multistep process of bronchogenic carcinogenesis may make these tasks more surmountable. During these same three decades, techniques have been developed which allow transfer of functional genes into mammalian cells. For example, blockade of activated tumor‐promoting oncogenes or replacement of inactivated tumor‐suppressing or apoptosis‐promoting genes can be achieved by gene therapy. This article will discuss the therapeutic implications of these molecular changes associated with bronchogenic carcinomas and will then review the status of gene therapies for treatment of lung cancer. J. Cell. Biochem. © 2006 Wiley‐Liss, Inc.
Changes in motility, gene expression and actin dynamics: Cdk6‐induced cytoskeletal changes associated with differentiation in mouse astrocytes
Authors: Slomiany Peter , Baker Thomas , Elliott Emily R. , Grossel Martha J.
Published: June 2006

Cyclin dependent kinase (cdk) 4 and cdk6 have historically been understood to be D‐cyclin kinases that phosphorylate pRb in the nucleus to regulate G1 phase of the cell cycle. In conflict with this understood redundancy are several studies that have demonstrated a novel role for cdk6 in differentiation. Cdk6 expression must be reduced to allow proper osteoblast and osteoclast differentiation, enforced cdk6 expression blocked differentiation of mouse embryo fibroblasts, and cdk6 expression in primary astrocytes favored the expression of progenitor cell markers (Ericson et al. [2003] Mol Cancer Res 1:654–664; Matushansky et al. [2003] Oncogene 22:4143–4149; Ogasawara et al. [2004a] J Bone Miner Res 19:1128–1136; Ogasawara et al. [2004b] Mol Cell Biol 24:6560–6568). Experiments shown here investigate novel cytoplasmic and nuclear functions of cdk6. These data demonstrate that cdk6 expression in mouse astrocytes results in changes in patterns of gene expression, changes in the actin cytoskeleton including loss of stress fibers, and enhanced motility. These changes in cdk6‐infected cells are associated with the process of cellular differentiation. J. Cell. Biochem. 99: 635–646, 2006. © 2006 Wiley‐Liss, Inc.
Comparing real‐world advantages for the clinical neuroradiologist between a high field (3 T), a phased array (1.5 T) vs. a single‐channel 1.5‐T MR system
Authors: Orbach Darren B. , Wu Chris , Law Meng , Babb James S. , Lee Ray , Padua Abraham , Knopp Edmond A.
Published: June 2006

Purpose

To evaluate signal‐to‐noise ratio (SNR) and neuroradiologists' subjective assessments of image quality in 3‐Tesla (3‐T) or phased‐array MR systems that are now available for clinical neuroimaging.

Materials and Methods

Brain MR images of six normal volunteers were obtained on each of three scanners: a 1.5‐T single‐channel system, a 12‐channel, phased‐array system, and a 3‐T single‐channel system. Additionally, clinically optimized images acquired from 28 patients who underwent imaging in more than one of these systems were analyzed. SNRs were measured and image quality and artifact conspicuity were graded by two blinded readers.

Results

The phased‐array system produced higher SNR than either the 1.5‐T or the 3‐T single‐channel systems, and in no instance was it outperformed. Both blinded readers judged the phased‐array images to be of higher quality than those produced by the single‐channel systems, with significantly less artifact. The 3‐T magnet produced images with high SNR, but with increased artifact conspicuity. The phased‐array system markedly decreased acquisition times without introduction of artifacts.

Conclusion

Both quantitatively and qualitatively, the phased‐array system provided image quality superior to that of the 1.5‐T and 3‐T single‐channel systems. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Comparison of the magnetization transfer ratio and fluid‐attenuated inversion recovery imaging signal intensity in differentiation of various cystic intracranial mass lesions and its correlation with biological parameters
Authors: Mishra Asht M. , Reddy Sangala J. , Husain Mazhar , Behari Sanjay , Husain Nuzhat , Prasad Kashi N. , Kumar Sunil , Gupta Rakesh K.
Published: June 2006

Purpose

To compare the signal intensity on the fluid attenuated inversion recovery (FLAIR) sequence and magnetization transfer ratios (MTRs) for the differentiation of abscesses from non‐abscess cystic brain lesions, and to correlate these MR parameters with the viscosity, viable cell density and total protein concentration of the cystic fluid.

Materials and Methods

Signal intensity on FLAIR and MTRs from the cystic cavity of lesions were calculated from 33 patients (brain abscess (N = 12) and non‐abscess (N = 21)). The fluid from the lesion was aspirated at the time of surgery, and the viscosity, viable cell density, and total protein concentration were measured.

Results

Signal intensity on FLAIR correlated significantly with the total protein concentration in abscess (r = 0.60, P < 0.05) and non‐abscess lesions (r = 0.41, P < 0.05). However, there was no significant difference (P > 0.05) in the FLAIR signal intensity of the abscess (318.8 ± 75) and non‐abscess group (258 ± 47). The MTR of the brain abscesses (13 ± 0.95) was significantly higher (P < 0.05) than that of the non‐abscess group (3.5 ± 0.3). A significant correlation was observed between MTR and viscosity (r = 0.75, P < 0.05), total protein concentration (r = 0.60, P < 0.05), and cell density (r = 0.70, P < 0.05) in brain abscess, and viscosity (r = 0.81, P < 0.05) and total protein concentration (r = 0.41, P < 0.05) in non‐abscess lesions.

Conclusion

It is possible to differentiate brain abscesses from non‐abscess cystic lesions using MT imaging. The MTR correlates significantly with the viscosity, viable cell density, and total protein concentration in brain abscess, and with viscosity and total protein concentration in non‐abscess lesions. FLAIR signal intensity correlates significantly only with the total protein concentration in abscess and non‐abscess lesions. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
In vivo DTI evaluation of white matter tracts in rat spinal cord
Authors: Gullapalli Jayaroop , Krejza Jaroslaw , Schwartz Eric D.
Published: June 2006

Purpose

To determine whether differences in specific spinal cord white matter (WM) tracts can be detected with in vivo DTI.

Materials and Methods

In vivo DTI was performed on six rats at the lower thoracic region using a 4.7T magnet. Axial diffusion images were obtained with diffusion gradients applied in six independent directions, with low and high b‐values equal to 0 and 692 seconds/mm2, respectively. Regions of interest (ROIs) were selected corresponding to the major spinal cord tracts, including the dorsal cortical spinal tract (dCST), fasciculus gracilis (FG), rubrospinal tract (RST), vestibulospinal tract (VST), and reticulospinal tract (ReST).

Results

ANOVA demonstrated overall differences between tracts for all of the DTI parameters, including fractional anisotropy (FA), trace diffusion (Tr), longitudinal diffusivity (EL = λ1), and transverse diffusivity (ET = (λ2 + λ3)/2). Similarly to previous ex vivo analyses, the spinal cord tract with the largest and most widely spaced axons (VST) had the largest EL and ET.

Conclusion

The principal diffusivities appear to reflect axon morphologic differences between the WM tracts that are not as well appreciated with FA and Tr. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
In silico predictability of allergenicity: From amino acid sequence via 3‐D structure to allergenicity
Authors: Aalberse Rob C. , Stadler Beda M.
Published: June 2006

In relation to the prediction of allergenicity three aspects have to be discussed: IgE immunogenicity, IgE cross‐reactivity, and T‐cell cross‐reactivity. IgE immunogenicity depends largely on factors other than the protein itself: the context and dose and “history” of the protein by the time it reaches the immune system. It is, therefore, not fully predictable from structural information. In contrast, IgE cross‐reactivity can be much more reliably assessed by in‐silico homology searches in combination with in vitro IgE antibody assays. The in‐silico homology search is unlikely to miss potential cross‐reactivity with sequenced allergens. So far, no biologically relevant cross‐reactivity at the antibody level has been demonstrated between proteins without easily demonstrable homology. T‐cell cross‐reactivity is much more difficult to predict than B‐cell cross‐reactivity. Moreover, its effects are more diverse. Yet, pre‐existing cross‐reactive T‐cell activity is likely to influence the outcome not only of the immune response, but also of the effect phase of the allergic reaction. The question of whether any antigen can be allergenic is still a matter of debate.
Evaluation of available IgE‐binding epitope data and its utility in bioinformatics
Authors: Bannon Gary A. , Ogawa Tadashi
Published: June 2006

This paper reviews the role played by IgE‐binding epitopes in eliciting clinical symptoms, the types of IgE‐binding epitopes in allergenic proteins, the methods used to identify IgE‐binding epitopes, and the availability of IgE‐binding epitopes in allergenic sources. Finally, bioinformatics methods to assess protein allergenicity using knowledge of IgE‐binding epitopes are discussed.
32‐channel 3 Tesla receive‐only phased‐array head coil with soccer‐ball element geometry
Authors: Wiggins G.C. , Triantafyllou C. , Potthast A. , Reykowski A. , Nittka M. , Wald L.L.
Published: June 2006

A 32‐channel 3T receive‐only phased‐array head coil was developed for human brain imaging. The helmet‐shaped array was designed to closely fit the head with individual overlapping circular elements arranged in patterns of hexagonal and pentagonal symmetry similar to that of a soccer ball. The signal‐to‐noise ratio (SNR) and noise amplification (g‐factor) in accelerated imaging applications were quantitatively evaluated in phantom and human images and compared with commercially available head coils. The 32‐channel coil showed SNR gains of up to 3.5‐fold in the cortex and 1.4‐fold in the corpus callosum compared to a (larger) commercial eight‐channel head coil. The experimentally measured g‐factor performance of the helmet array showed significant improvement compared to the eight‐channel array (peak g‐factor 59% and 26% of the eight‐channel values for four‐ and fivefold acceleration). The performance of the arrays is demonstrated in high‐resolution and highly accelerated brain images. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Real‐time RF pulse adjustment for B0 drift correction
Authors: Benner Thomas , van der Kouwe André J.W. , Kirsch John E. , Sorensen A. Gregory
Published: June 2006

Although the magnetic field of an MR scanner is very stable under little or no load, it can become less stable under heavy‐duty cycle conditions, such as in diffusion tensor imaging (DTI). Uncorrected, such field drifts lead to an apparent image shift along the phase‐encoding direction and decreasing effectiveness of fat saturation pulses. A method is presented to adjust the center frequency of all RF pulses and the receiver in real time during the acquisition. No data postprocessing or changes to the sequence timing are necessary. In vivo acquisitions were performed to assess the prolonged effectiveness of fat saturation. Field drifts of approximately 2.5 Hz/min were measured and corrected during DTI acquisitions at b‐values of up to 3000 s/mm2. The effectiveness of fat saturation diminished over the duration of an 18‐min acquisition when the drift was left uncorrected. The proposed method corrects for apparent image shift and ensures continuously effective fat saturation over the duration of an acquisition. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Quantitative CBV measurement from static T1 changes in tissue and correction for intravascular water exchange
Authors: Shin Wanyong , Cashen Ty A. , Horowitz Sandra W. , Sawlani Rahul , Carroll Timothy J.
Published: June 2006

The steady‐state (SS) approach has been proposed to measure quantitative cerebral blood volume (CBV). However, it is known that the CBV value in SS (CBVSS) is subject to error resulting from the effects of water diffusion from the intra‐ to extravascular space. CBVSS measurements were simulated in both fast‐ and no‐water‐exchange limits, and compared with measured CBVSS values to determine which limiting case is appropriate. Twenty‐eight patients were scanned with a segmented Look‐Locker echo‐planar imaging (LL‐EPI) sequence before and after the injection of 0.1 mmol/kg of a T1‐shortening contrast agent. Signal changes and T1 values of brain parenchyma and the blood pool were measured pre‐ and postcontrast. These signal changes and T1 values, in combination with the simulated results, were used to estimate water‐exchange rates. We found that the intra‐ to extravascular water‐exchange rates in white matter (WM) and gray matter (GM) were 0.9 and 1.6 s–1, respectively. With these water‐exchange rates, the fast‐water‐exchange limit of the CBV values showed good agreement with the simulation (r = 0.86 in WM, and 0.78 in GM). The CBV values with the correction for water‐exchange effects were recalculated as 2.73 ± 0.44 and 5.81 ± 1.12 of quantitative cerebral blood water volume (%) in WM and GM, respectively. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Robust fully automated shimming of the human brain for high‐field 1H spectroscopic imaging
Authors: Hetherington Hoby P. , Chu Wen‐Jang , Gonen Oded , Pan Jullie W.
Published: June 2006

Although a variety of methods have been proposed to provide automated adjustment of shim homogeneity, these methods typically fail or require large numbers of iterations in vivo when applied to regions with poor homogeneity, such as the temporal lobe. These limitations are largely due to 1) the limited accuracy of single evolution time measurements when full B0 mapping studies are used, and 2) inaccuracies arising from projection‐based methods when the projections pass through regions where the inhomogeneity exceeds the order of the fitted parameters. To overcome these limitations we developed a novel B0 mapping method using multiple evolution times with a novel unwrapping scheme in combination with a user‐defined ROI selection tool. We used these methods at 4T on 10 control subjects to obtain high‐resolution spectroscopic images of glutamate from the bilateral hippocampi. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Measurement of xenon diffusing capacity in the rat lung by hyperpolarized 129Xe MRI and dynamic spectroscopy in a single breath‐hold
Authors: Abdeen Nishard , Cross Albert , Cron Gregory , White Steven , Rand Thomas , Miller David , Santyr Giles
Published: June 2006

We used the dual capability of hyperpolarized 129Xe for spectroscopy and imaging to develop new measures of xenon diffusing capacity in the rat lung that (analogously to the diffusing capacity of carbon monoxide or DLCO) are calculated as a product of total lung volume and gas transfer rate constants divided by the pressure gradient. Under conditions of known constant pressure breath‐hold, the volume is measured by hyperpolarized 129Xe MRI, and the transfer rate is measured by dynamic spectroscopy. The new quantities (xenon diffusing capacity in lung parenchyma (DLXeLP)), xenon diffusing capacity in RBCs (DLXeRBC), and total lung xenon diffusing capacity (DLXe)) were measured in six normal rats and six rats with lung inflammation induced by instillation of fungal spores of Stachybotrys chartarum. DLXeLP, DLXeRBC, and DLXe were 56 ± 10 ml/min/mmHg, 64 ± 35 ml/min/mmHg, and 29 ± 9 ml/min/mmHg, respectively, for normal rats, and 27 ± 9 ml/min/mmHg, 42 ± 27 ml/min/mmHg, and 16 ± 7 ml/min/mmHg, respectively, for diseased rats. Lung volumes and gas transfer times for LP (TtrLP) were 16 ± 2 ml and 22 ± 3 ms, respectively, for normal rats and 12 ± 2 ml and 35 ± 8 ms, respectively, for diseased rats. Xenon diffusing capacities may be useful for measuring changes in gas exchange associated with inflammation and other lung diseases. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Diffusion of myelin water
Authors: Andrews Trevor J. , Osborne Michael T. , Does Mark D.
Published: June 2006

We studied compartmentally specific characteristics of water diffusion in excised frog sciatic nerve by combining T1 or T2 selective acquisitions with pulse‐gradient spin‐echo (PGSE) diffusion weighting, with the specific objective of characterizing myelin water diffusion. Combining a PGSE with a Carr‐Purcell‐Meiboom‐Gill (CPMG) acquisition provided apparent diffusion coefficients (ADCs) for each of the three T2 components found in nerve, including the short‐lived component believed to be derived from myelin water. Double‐inversion‐recovery (DIR) preparation provided an alternate means of discriminating myelin water, and in combination with PGSE provided somewhat different measures of ADC. The DIR measures yielded myelin water ADCs of 0.37 μm2/ms (parallel to nerve) and 0.13 μm2/ms (perpendicular to nerve). These ADC estimates were postulated to be more accurate than those based on T2 discrimination, although the difference between the two findings is not clear. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
High magnetic field water and metabolite proton T1 and T2 relaxation in rat brain in vivo
Authors: de Graaf Robin A. , Brown Peter B. , McIntyre Scott , Nixon Terence W. , Behar Kevin L. , Rothman Douglas L.
Published: June 2006

Comprehensive and quantitative measurements of T1 and T2 relaxation times of water, metabolites, and macromolecules in rat brain under similar experimental conditions at three high magnetic field strengths (4.0 T, 9.4 T, and 11.7 T) are presented. Water relaxation showed a highly significant increase (T1) and decrease (T2) with increasing field strength for all nine analyzed brain structures. Similar but less pronounced effects were observed for all metabolites. Macromolecules displayed field‐independent T2 relaxation and a strong increase of T1 with field strength. Among other features, these data show that while spectral resolution continues to increase with field strength, the absolute signal‐to‐noise ratio (SNR) in T1/T2‐based anatomical MRI quickly levels off beyond ∼7 T and may actually decrease at higher magnetic fields. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Comparative genomic hybridization reveals genetic progression of oral squamous cell carcinoma from dysplasia via two different tumourigenic pathways
Authors: Noutomi Y , Oga A , Uchida K , Okafuji M , Ita M , Kawauchi S , Furuya T , Ueyama Y , Sasaki K
Published: June 2006

To clarify the genetic pathway(s) involved in the development and progression of oral squamous cell carcinoma (OSCC), as well as the relationship between genetic aberrations and biological characteristics of OSCC tumours, comparative genomic hybridization was used to analyse genetic alterations in both primary OSCCs and adjacent dysplastic lesions of the same biopsy specimens from 35 patients. Gain of 8q22–23 was the most frequent alteration in both OSCC and mild dysplasia, and was considered the earliest event in the process of oral tumourigenesis. The average number of DNA sequence copy number aberrations (DSCNAs) increased with progression from mild dysplasia to invasive carcinoma (r = 0.737, n = 70, p < 0.001). OSCC samples were classified as having a large or small number of DSCNAs (OSCC‐L, 21.4 ± 4.7 DSCNAs or OSCC‐S, 10.0 ± 1.7 DSCNAs, respectively; p < 0.0001). Gains of 3q26‐qter, 8q, 11q13, 14q, and 20q and losses of 4q, 5q12–22, 6q, 8p, 13q, and 18q22‐qter were common to OSCC‐L and OSCC‐S. Gains of 5p15, 7p, 17q11–22, and 18p and losses of 3p14–21, 4p, and 9p were detected exclusively in OSCC‐L. The average number of DSCNAs depended on whether the samples showed OSCC‐ L or dysplasia plus OSCC‐L, or showed OSCC‐S or dysplasia plus OSCC‐S (p = 0.001). Gain of 5p15 and losses of 4p and 9p were detected even in dysplastic lesions adjacent to OSCC‐L samples. Loss of 4p was associated with node metastasis by multivariate analysis (p = 0.013). OSCC‐L tumours were more often T3–T4 stage tumours than T1–T2 stage tumours (p = 0.03). These findings suggest that two different types of OSCC, OSCC‐L associated with high‐stage cancer and OSCC‐S associated with low‐stage cancer, arise from different types of dysplasia via different genetic pathways. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Mortality among 5‐year survivors of cancer diagnosed during childhood or adolescence in British Columbia, Canada
Authors: MacArthur Amy C. , Spinelli John J. , Rogers Paul C. , Goddard Karen J. , Abanto Zenaida U. , McBride Mary L.
Published: June 2006

Background

Ongoing monitoring of late mortality among survivors of a childhood or adolescent cancer is essential to appropriately evaluate risk in more recent cohorts and with longer follow‐up. We examined overall and cause‐specific mortality in a population‐based cohort of 2,354 individuals diagnosed with a cancer or tumor prior to 20 years of age between 1970 and 1995 in British Columbia (BC), Canada who survived at least 5 years.

Procedure

Late deaths in a survivor cohort ascertained from the BC Cancer Registry were identified using death registrations. Standardized mortality ratios, absolute excess risk of death, and cumulative risk of death were determined. Demographic, temporal, and disease‐related factors in risk of late mortality were also assessed.

Results

After 24,491 person‐years of follow‐up, there were 181 deaths, 139 of which were cancer related. Excess risk of late mortality among survivors was 7 deaths per 1,000 person‐years at risk (AER = 6.6). Standardized mortality ratio (SMR) was ninefold higher relative to the underlying BC population (SMR = 9.1, 95% CI, 7.8–10.5), and was greatest for those with a recurrence within 5 years of diagnosis, and for those diagnosed with acute lymphoblastic leukemia and nervous system tumors. Absolute excess risk of late death was significantly higher for males and for those diagnosed prior to 1980, but did not vary according to age at diagnosis. Relative mortality was significantly increased due to cancer‐related causes of death (SMR = 81.7, 95% CI, 68.6–95.8), as well as circulatory (SMR = 9.7, 95% CI, 4.2–19.1) and respiratory (SMR = 16.8, 95% CI, 4.6–43.0) diseases.

Conclusions

In this population‐based cohort with long follow‐up, there continues to be excess late mortality among childhood and adolescent cancer survivors due to both cancer and non‐cancer causes, even among more recently diagnosed survivors. Pediatr Blood Cancer © 2006 Wiley‐Liss, Inc.
Outcome of fetal cerebral posterior fossa anomalies
Authors: Long Audrey , Moran Paul , Robson Stephen
Published: June 2006

Introduction

Limited data exist on the outcome of Dandy–Walker malformation (DWM), Dandy–Walker variant (DWV) and mega‐cisterna magna (MCM). We report the first population‐based study of posterior fossa anomalies from the northern region of England.

Methods

Cases were identified from the Northern Congenital Abnormality Survey (NorCAS) and regional Fetal Medicine Unit databases for the period 1986–2004 for DWM/V and 1995–2005 for MCM (defined as a cisterna magna ≥10 mm). Outcome data was obtained from pediatric records and/or general practitioner/health visitor questionnaires for all survivors.

Results

A prenatal diagnosis of a posterior fossa abnormality was made in 91 cases, with a further 12 cases of DWM/V diagnosed postnatally, giving incidences of DWM/V and MCM of 1/11574 and 1/8268 births respectively. In five cases where DWM/V was suspected prenatally, the diagnosis was not confirmed. Of the 47 with DWM/V, 41 (87%) had additional anomalies. There were three survivors, all with neurodevelopmental disability. Of the 39 cases of MCM, 24 (62%) had additional anomalies. There were 30 survivors; one child died at 3 months and the outcome was normal in 25 children including 12/13 (92%) with isolated MCM.

Posterior fossa anomalies are relatively common. The outcome is very poor in DWM/V owing to the high rate of associated anomalies. The outcome appears better with MCM, especially if this is an isolated finding. Copyright © 2006 John Wiley & Sons, Ltd.
Highly fluorinated compounds induce phase separation in, and nanostructuration of liquid media. Possible impact on, and use in chemical reactivity control
Authors: Krafft Marie Pierre
Published: June 2006

Liquid perfluorocarbons‐like supercritical CO2‐provide valuable reaction media that can facilitate the separation of reaction products and the recovery of catalysts. Chemistry in fluorous media requires that some of the protagonist molecules, and in particular the catalysts, be grafted with one or more perfluoroalkylated chains. These chains, due to powerful hydrophobic and lipophobic effects, tend to self‐assemble and induce the formation of a variety of nanocompartmented supramolecular architectures and colloids, such as micelles, vesicles, tubules, monolayers, and emulsions, thus generating microheterogenicity in the reaction medium. Fluorinated amphiphiles are, for example, known to generate fibrous gels in fluorous, organic, and aqueous media. Phase separation, nanocompartmentation, and interface‐driven parameters can thus complicate otherwise simple chemistry. Conversely, they can provide useful micro‐ and nanoreactors and templates. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4251–4258, 2006
Laser composite surfacing of stainless steel with SiC
Authors: Majumdar J. Dutta , Chandra B. Ramesh , Nath A. K. , Manna I.
Published: June 2006

In the present study, an attempt has been made to improve wear resistance of AISI 304 stainless steel by laser composite surfacing with SiC. Laser processing has been carried out by pre‐deposition of Fe + SiC powders (in the ratio of 85:15 and thickness of 100 μm) on AISI 304 stainless steel substrate and subsequently, melting it using a 2 kW continuous wave CO2 laser. Following laser processing, a detailed characterization and evaluation of mechanical/electrochemical properties of the composite layer were undertaken to study the influence of laser processing on the characteristics and properties of the composite layer. Microstructure of the composite layer consisted of uniformly dispersed SiC particles in grain refined α‐Fe dendrites. Laser composite surfacing led to a significant improvement in microhardness and wear resistance as compared to as‐received substrate. However, pitting corrosion property was marginally deteriorated due to laser composite surfacing. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improved analysis of ladderane lipids in biomass and sediments using high‐performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Hopmans Ellen C. , Kienhuis Michiel V. M. , Rattray Jayne E. , Jaeschke Andrea , Schouten Stefan , Damsté Jaap S. Sinninghe
Published: June 2006

Ladderane lipids, containing three or five linearly concatenated cyclobutane moieties, are considered to be unique biomarkers for the process of anaerobic ammonium oxidation, an important link in the oceanic nitrogen cycle. Due to the thermal lability of the strained cyclobutane moieties, the ladderane lipids are difficult to analyze by gas chromatography. A method combining high‐performance liquid chromatography coupled to positive ion atmospheric pressure chemical ionization tandem mass spectrometry (HPLC/APCI‐MS/MS) was developed for the analysis of the most abundant ladderane lipids, occurring as fatty acids and ether‐bound to glycerol. Detection was achieved by selective reaction monitoring of four specific fragmentations per ladderane lipid. Detection limits of 30–35 pg injected on‐column and a linear response (r2 > 0.99) over nearly 3 orders of magnitude were achieved for all compounds. Using this method, these unique ladderane lipids were for the first time identified in a surface sediment from the Gullmarsfjorden, in concentrations ranging from 1.1–5.5 ng/g for the ladderane fatty acids and of 0.7 ng/g for the monoether. It is foreseen that this method will allow the investigation of the occurrence of anaerobic ammonium oxidation in natural settings in much greater detail than before. Copyright © 2006 John Wiley & Sons, Ltd.
The robotic approach for mediastinal lesions
Authors: Augustin Florian , Schmid Thomas , Bodner Johannes
Published: June 2006

Background

We report here our institutional experience and reflect the relevant literature concerning the robotic approach in diagnostic and therapeutic interventions for mediastinal lesions.

Methods

During August 2001–December 2005, 33 patients (15 males and 18 females aged 18–77 years) with mediastinal masses were operated on minimally invasively using the da Vinci™ robotic system. There were 22 thymectomies (nine thymomas), four resections of paravertebral neurinomas, one ectopic mediastinal parathyroidectomy, one resection of a lymphangioma, one resection of ectopic goitre, one resection of lymph node metastasis of thyroid carcinoma and three oesophageal procedures (one leiomyoma, one traction diverticulum and one foregut cyst).

Results

There were three (9%) open conversions due to surgical problems, 30 procedures (91%) were completed successfully using the da Vinci™ robot. There was no surgical mortality, no relevant intraoperative blood loss and no major surgical complication in any of the patients. As a minor complication (3%), an incomplete and transient palsy of the left laryngeal recurrent nerve was observed after resection of a tumour from the aortopulmonary window. The median overall operation time was 134 (range 54–314) min, including 103 (range 39–272) min for the robotic act.

Conclusions

Various different mediastinal procedures have been shown to be feasible and safe when performed with the robot. As the technical benefits of the da Vinci™ system are most advantageous in tiny and difficult‐to‐reach anatomical regions, the mediastinum should remain an area of special interest for robotic surgeons. Randomized trials and follow‐up studies have been initiated in order to evaluate the clinical impact of the robotic approach. Copyright © 2006 John Wiley & Sons, Ltd.
B6‐responsive disorders: A model of vitamin dependency
Authors: Clayton Peter T.
Published: June 2006

Pyridoxal phosphate is the cofactor for over 100 enzyme‐catalysed reactions in the body, including many involved in the synthesis or catabolism of neurotransmitters. Inadequate levels of pyridoxal phosphate in the brain cause neurological dysfunction, particularly epilepsy. There are several different mechanisms that lead to an increased requirement for pyridoxine and/or pyridoxal phosphate. These include: (i) inborn errors affecting the pathways of B6 vitamer metabolism; (ii) inborn errors that lead to accumulation of small molecules that react with pyridoxal phosphate and inactivate it; (iii) drugs that react with pyridoxal phosphate; (iv) coeliac disease, which is thought to lead to malabsorption of B6 vitamers; (v) renal dialysis, which leads to increased losses of B6 vitamers from the circulation; (vi) drugs that affect the metabolism of B6 vitamers; and (vii) inborn errors affecting specific pyridoxal phosphate‐dependent enzymes. The last show a very variable degree of pyridoxine responsiveness, from 90% in X‐linked sideroblastic anaemia (δ‐aminolevulinate synthase deficiency) through 50% in homocystinuria (cystathionine β‐synthase deficiency) to 5% in ornithinaemia with gyrate atrophy (ornithine δ‐aminotransferase deficiency). The possible role of pyridoxal phosphate as a chaperone during folding of nascent enzymes is discussed. High‐dose pyridoxine or pyridoxal phosphate may have deleterious side‐effects (particularly peripheral neuropathy with pyridoxine) and this must be considered in treatment regimes. None the less, in some patients, particularly infants with intractable epilepsy, treatment with pyridoxine or pyridoxal phosphate can be life‐saving, and in other infants with inborn errors of metabolism B6 treatment can be extremely beneficial.
Trends in haematopoietic cell transplantation for inborn errors of metabolism
Authors: Boelens Jaap Jan
Published: June 2006

For the last 25 years, haematopoietic cell transplantation (HCT) has been used as effective therapy for selected inborn errors of metabolism (IEMs), mainly lysosomal storage diseases and peroxisomal disorders. The main rational for HCT in IEMs is based on the provision of correcting enzymes by donor cells within and outside the blood compartment. The ultimate goal of HCT is to achieve a normal or near‐normal life and normal neurodevelopment. HCT has been performed for more than 20 diseases. Only for Hurler syndrome, X‐ALD and infantile Krabbe disease, are detailed studies available suggesting that HCT is indicated for carefully selected cases. Improvement of transplantation techniques and alternative therapies may change the recommended (contra‐)indications for IEM. A recent example of emerging transplantation techniques is the fast availability of unrelated cord blood (UCB). UCB makes HCT feasible in patients with rapidly progressive neurological diseases. Because of the fast availability of UCB and therefore the ability to transplant shortly after diagnosis, there is no indication for patients in a moderate/good clinical condition to receive enzyme replacement therapy (ERT; in Hurler syndrome) prior to or during HCT and can ERT only be considered in patients with poor clinical condition. Mesenchymal stem cell infusions with HCT is an emerging technique, and might be interesting in halting the remaining defects after successful HCT. Improvement in HCT techniques and novel stem cell sources will significantly impact the safety and efficacy of this therapy as well as expand the list of candidate disorders. A good functioning worldwide registry would be necessary to measure the effects of the procedures performed in more detail.
Screening for lysosomal storage disorders—A clinical perspective
Authors: Fletcher Janice M.
Published: June 2006

The availability of therapies for lysosomal storage diseases (LSDs) and clear documentation from animal studies that optimal therapy depends on early diagnosis have set the scene for newborn screening for LSDs. The combined incidence of this group of conditions is approximately 1 in 7000, well within the feasible range for newborn screening programmes. The availability of multiplex technology has facilitated the technical aspects of initial screening. The scientific challenge is to predict disease severity early enough to influence choice of therapy. LSD screening is discussed from the point of view of the scientists, the families affected by these conditions, the community and clinicians.
Anaplerotic molecules: Current and future
Authors: Brunengraber Henri , Roe Charles R.
Published: June 2006

This review presents the concepts of anaplerosis and cataplerosis in relation to the regulation of citric acid cycle operation. Anaplerosis is the re‐filling of the catalytic intermediates of the cycle that carry acetyl‐CoA as it is oxidized. The main anaplerotic substrates are pyruvate, glutamine/glutamate and precursors of propionyl‐CoA (odd‐chain fatty acids, specific amino acids, C5‐ketone bodies). Cataplerosis balances anaplerosis by removing excess intermediates from the citric acid cycle. The properties of the main anaplerotic substrates are reviewed from the point of view of potential clinical applications to the treatment of some inherited and acquired conditions.
Some Results on Mean Square Error for Factor Score Prediction
Authors: Krijnen Wim P.
Published: June 2006

For the confirmatory factor model a series of inequalities is given with respect to the mean square error (MSE) of three main factor score predictors. The eigenvalues of these MSE matrices are a monotonic function of the eigenvalues of the matrix Γp = Φ1/2Λ′pΨp−1ΛpΦ1/2. This matrix increases with the number of observable variables p. A necessary and sufficient condition for mean square convergence of predictors is divergence of the smallest eigenvalue of Γp or, equivalently, divergence of signal-to-noise (Schneeweiss & Mathes, 1995). The same condition is necessary and sufficient for convergence to zero of the positive definite MSE differences of factor predictors, convergence to zero of the distance between factor predictors, and convergence to the unit value of the relative efficiencies of predictors. Various illustrations and examples of the convergence are given as well as explicit recommendations on the problem of choosing between the three main factor score predictors.
Laser arytenoidectomy in children with bilateral vocal fold immobility
Authors: Worley G , Bajaj Y , Cavalli L , Hartley B
Published: June 2006

Bilateral vocal fold immobility in children is a challenging problem because a balance between good airway and voice quality has to be achieved. Surgery to improve the airway is often postponed or avoided because of fear of losing the voice. In this study our results of laser arytenoidectomy in children are described. This was a retrospective case notes review at a tertiary level paediatric ENT department. The six patients in this case series ranged from nine to 16 years old at the time of laser arytenoidectomy. Post-operative airway and voice quality were assessed. All children in the series had an adequate post-operative airway. Four of these patients had tracheostomies pre-operatively and achieved decannulation. All six patients rated their post-operative voice as better than pre-operatively. This is principally due to increased loudness associated with increased airflow through the larynx, particularly after tracheostomy decannulation. It is recommended that special care should be taken not to disturb the anterior two thirds of the vocal fold during the surgery in order to achieve a good post-operative voice outcome.
A safer way to aspirate a quinsy
Authors: Flook E , SriKumar S , Johnston M
Published: June 2006

Quinsies (peritonsillar abscesses) are routinely treated in all ENT departments. This paper outlines a technique for safe aspiration of a quinsy, which minimizes the risk to adjacent structures.
Cerebellopontine angle meningioma resulting in middle-ear polyp
Authors: Hanna S J , Derham C , Hille P Van , Fenwick J D
Published: June 2006

Extracranial spread of meningiomas to involve the middle ear is very rare. We present the case of a 43-year-old woman with a known cerebellopontine angle meningioma who subsequently presented with left-sided otalgia and a middle-ear mass extruding through the tympanic membrane due to local invasion of the meningioma. The tumour was excised surgically. A discussion of the relevant literature is also presented.