bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractAlthough 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

AbstractWe 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

AbstractWe 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

AbstractComprehensive 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

AbstractTo 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

AbstractBackgroundOngoing 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.ProcedureLate 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.ResultsAfter 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.ConclusionsIn 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

AbstractIntroductionLimited 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.MethodsCases 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.ResultsA 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.SummaryPosterior 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

AbstractLiquid 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

AbstractIn 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

AbstractLadderane 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

AbstractBackgroundWe report here our institutional experience and reflect the relevant literature concerning the robotic approach in diagnostic and therapeutic interventions for mediastinal lesions.MethodsDuring 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).ResultsThere 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.ConclusionsVarious 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

SummaryPyridoxal 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

SummaryFor 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

SummaryThe 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

SummaryThis 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.