bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain MRI: Tumor evaluation
Authors: Young Robert J. , Knopp Edmond A. 
Published: September 2006

AbstractThe designation “brain tumors” is commonly applied to a wide variety of intracranial mass lesions that are distinct in their location, biology, treatment, and prognosis. Since many of these lesions do not arise from brain parenchyma, the more appropriate term would be “intracranial tumors.” The term “tumor” is used to include both neoplastic and non‐neoplastic mass lesions, and should be considered in its broadest sense to simply indicate a space‐occupying mass. This review describes an imaging‐based approach for evaluating intracranial tumors. Conventional MRI is discussed in the setting of a regional classification system. This system provides a framework for analysis, and imaging clues can then be applied to narrow the differential possibilities. Emphasis is placed on advanced MRI techniques and their utility for deciphering common diagnostic problems. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Evaluation of different cerebral mass lesions by perfusion‐weighted MR imaging
Authors: Hakyemez Bahattin , Erdogan Cuneyt , Bolca Naile , Yildirim Nalan , Gokalp Gokhan , Parlak Mufit 
Published: September 2006

AbstractPurposeTo investigate the contribution of perfusion‐weighted MR imaging (PWI) by using the relative cerebral blood volume (rCBV) ratio in the differential diagnosis of various intracranial space‐occupying lesions.Materials and MethodsThis study involved 105 patients with lesions (high‐grade glioma (N = 26), low‐grade glioma (N= 11), meningioma (N = 23), metastasis (N = 25), hemangioblastoma (N = 6), pyogenic abscess (N = 4), schwannoma (N = 5), and lymphoma (N = 5)). The patients were examined with a T2*‐weighted (T2*W) gradient‐echo single‐shot EPI sequence. The rCBV ratios of the lesions were obtained by dividing the values obtained from the normal white matter. Statistical analysis was performed with the Mann‐Whitney U‐test. A P‐value less than 0.05 was considered statistically significant.ResultsThe rCBV ratio was 5.76 ± 3.35 in high‐grade gliomas, 1.69 ± 0.51 in low‐grade gliomas, 8.02 ± 3.89 in meningiomas, 5.27 ± 3.22 in metastases, 11.36 ± 4.41 in hemangioblastomas, 0.76 ± 0.12 in abscesses, 1.10 ± 0.32 in lymphomas, and 3.23 ± 0.81 in schwannomas. The rCBV ratios were used to discriminate between 1) high‐ and low‐grade gliomas (P < 0.001), 2) hemangioblastomas and metastases (P< 0.05), 3) abscesses from high‐grade gliomas and metastases (P < 0.001), 4) schwannomas and meningiomas (P < 0.001), 5) lymphomas from high‐grade gliomas and metastases (P < 0.001), and 6) typical meningiomas and atypical meningiomas (P < 0.01).ConclusionrCBV ratios can help discriminate intracranial space‐occupying lesions by demonstrating lesion vascularity. It is possible to discriminate between 1) high‐ and low‐grade gliomas, 2) hemangioblastomas and other intracranial posterior fossa masses, 3) abscesses from high‐grade gliomas and metastases, 4) schwannomas and meningiomas, 5) lymphomas and high‐grade gliomas and metastases, and 6) typical and atypical meningiomas. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Magnetic resonance angiography of the human middle meningeal artery: Implications for migraine
Authors: Schoonman Guus G. , Bakker Dick , Schmitz Nicole , van der Geest Rob J. , van der Grond Jeroen , Ferrari Michael D. , van Buchem Mark A. 
Published: September 2006

AbstractPurposeTo describe a novel noninvasive method for studying middle meningeal artery (MMA) diameter changes in vivo in humans. Dilatation of the MMA has been implicated in the pathophysiology of migraine headache, but no direct evidence has been obtained in humans.Materials and MethodsThe diameter of the MMA (the extracranial part) was measured in 19 healthy volunteers before and after administration of a vasodilator (nitroglycerin (NTG), 1.2 mg sublingually) known to provoke headache. We used magnetic resonance angiography (MRA) in combination with a 47‐mm microscopy coil and a semiautomatic contour detection program.ResultsThe diameter of the MMA was 1.5 ± 0.26 mm (mean ± SD) before and 1.79 ± 0.30 mm after NTG administration. This increase was 20.1% (95% CI = 12.9–27.3; P < 0.001). The mean increase in subjects who developed headache (N = 11) was 0.34 ± 0.19 mm as compared to 0.22 mm ± 0.20 mm in the eight subjects who did not (95% CI for difference = −0.07 to 0.31; P = 0.188).ConclusionMRA in combination with a 47‐mm microscopy coil is a novel, noninvasive method to measure changes in the diameter of human meningeal vessels, with potential applications for migraine and other fields of neurovascular research. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
1H NMR spectroscopic imaging of the mouse brain at 9.4 T
Authors: Miyasaka Naoyuki , Takahashi Kan , Hetherington Hoby P. 
Published: September 2006

AbstractPurposeTo assess the feasibility of 1H spectroscopic imaging (SI) in the mouse brain at 9.4 T, and investigate regional variations in brain metabolites.Materials and MethodsA total of 21 SI studies were performed in CD‐1 mice to evaluate the basal ganglia (N = 5), hippocampus and thalamus (N = 11), and cerebellum (N = 5). We adjusted the B0 homogeneity for each slice using a fully automated shim calculation method based on the B0 map, which we measured using a multislice gradient‐echo sequence with multiple phase evolution delays. The SI employed a modified localization by adiabatic selective refocusing (LASER) sequence with TE/TR of 50/2000 msec, 24 × 24 encodes over a field of view (FOV) of 24 mm × 24 mm, 1 μL voxel resolution, and two averages, for a total acquisition time of 38 minutes.ResultsSufficient shimming was achieved and high‐quality spectra were consistently obtained in each slice. N‐acetyl aspartate (NAA)/creatine (Cr) ratios in the basal ganglia and thalamus (0.86 ± 0.07, and 0.87 ± 0.07, respectively) were significantly higher than those in the hippocampus and cerebellum (0.76 ± 0.03 and 0.67 ± 0.07), which were also significantly different from each other.Conclusion1H SI of the mouse brain is highly reproducible and allows differences in regional metabolite ratios to be easily visualized. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Contrast enhancement of manganese‐hydroxypropyl‐tetraacetic acid, an MR contrast agent with potential for detecting differences in myocardial blood flow
Authors: Eriksson Rolf , Johansson Lars , Bjerner Tomas , Karlsson Jan Olof G. , Ahlström Håkan 
Published: September 2006

AbstractPurposeTo determine whether the contrast agent MnHPTA has potential for detecting differences in myocardial blood flow.Materials and MethodsR1 in the myocardium was calculated from MR signal intensity measurements in 18 pigs after intravenous injection of 5, 15, or 25 μmol MnHPTA/kg body weight. Measurements were made in each animal after administration at rest and during dobutamine‐induced stress.ResultsA difference of approximately 0.1 sec−1 in the R1 increase between rest and stress still remained 31 minutes after administration of 25 μmol MnHPTA/kg body weight. When two consecutive MnHPTA injections were performed, the second injection induced a lower R1 increase than the corresponding first injection.ConclusionMnHPTA at a dose of 25 μmol/kg body weight (b.w.) has the potential to detect perfusion differences in myocardium. When two consecutive injections of MnHPTA were administered, the R1 change after the second injection was affected by the earlier administration. Therefore, a protocol including more than one administration is not ideal for this contrast agent. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Ethyl pyruvate attenuates kainic acid‐induced neuronal cell death in the mouse hippocampus
Authors: Cho Ik‐Hyun , Kim Seung‐Woo , Kim Jung‐Bin , Kim Tae‐Kyung , Lee Kang‐Woo , Han Pyung‐Lim , Lee Ja‐Kyeong 
Published: September 2006

AbstractRecent studies have shown that ethyl pyruvate (EP) acts as an anti‐inflammatory molecule in several cell lines including RAW264.7 macrophages. However, the potential therapeutic value of EP for the treatment of the pathologic brain has not been investigated fully. In the present study, we examined whether EP has a beneficial effect on KA‐induced neuronal cell death. Intracerebroventricular (i.c.v.) injection of 0.94 nmol (0.2 μg) of KA produced typical neuronal cell death in the CA1 and CA3 pyramidal layers of the hippocampus, and the systemic administration of EP significantly attenuated KA‐induced neuronal cell death in these regions. Ethyl pyruvate was found to exert a protective effect when it was injected as late as 12 hr after KA‐injection. Moreover, this EP‐induced neuroprotection was accompanied by reduced levels of reactive gliosis and COX‐2, IL‐1β, and TNF‐α in the hippocampus. In addition, in passive avoidance tests, KA‐induced memory impairment was improved markedly by EP. These results suggest that EP has a therapeutic potential for suppressing KA‐induced pathogenesis in the brain. © 2006 Wiley‐Liss, Inc.
Relative proportion of inorganic and total nitrogen in broiler litter as determined by various methods
Authors: Kpomblekou‐A Kokoasse 
Published: September 2006

AbstractWe report relative proportion of inorganic N in broiler litter and compare the regular Kjeldahl method with three of its modifications (the salicylic acid–thiosulfate modification, the Devarda's alloy modification, and the potassium permanganate–reduced iron modification), and with a Leco‐combustion (CHN‐600) method for the degree to which they include NO3−‐N and NO2−‐N in broiler litter analysis. Inorganic N in the litter (<500 µm) was determined after extraction with 2 mol L−1KCl. NH4+‐N and (NO3−+ NO2−)‐N in the filtrate were analysed by steam distillation while NO2−‐N was determined by a modified Griess–Ilosvay colorimetric method. For the determination of total N, 25 mg broiler litter (<1000 µm) was digested according to four semi‐micro‐Kjeldahl methods in a 100‐mL Pyrex Kjeldahl flask using an electrically heated six‐flask micro‐Kjeldahl digestion rack. Ammonium‐N in the digest was determined by steam distillation. The results showed that inorganic N represents a small portion of total N in the samples. Ammonium is the most dominant inorganic N (1.61–5.39 g kg−1) in the samples; it represents between 42 and 94% of the inorganic N. The (NO3−+ NO2−)‐N contents varied between 0.19 and 5.56 g kg−1while NO2−‐N contents in the samples were negligible (<0.6 g kg−1). The regular Kjeldahl method and its modifications recovered all the NH4+‐N added but recovery of added NO2−‐N and NO3−‐N varied considerably with the methods. The Devarda's alloy and the potassium permanganate methods showed the highest N measurements while the Leco‐combustion showed the lowest N measurements. Copyright © 2006 Society of Chemical Industry
Modelling the effect of superatmospheric oxygen concentrations on in vitro mushroom PPO activity
Authors: Gómez Perla A , Geysen Sabine , Verlinden Bert E , Artés Francisco , Nicolaï Bart M 
Published: September 2006

AbstractThe kinetics of polyphenol oxidase (PPO, EC 1.14.18.1) with respect to oxygen concentrations from 5 to 100% using chlorogenic acid (CGA) as substrate was examined. In vitro mushroom PPO activity was determined by measuring the consumption of oxygen during the oxidation reaction. A differential Michaelis–Menten model was fitted to the obtained total depletion curves. The product concentration as well as the concentration of oxygen had a clear inhibitory effect on the reaction rate. However, the inhibitory effect of oxygen was more evident at low product concentration. A linear mixed inhibition model that considered both the product (oxidised CGA) and oxygen as inhibitors was developed. A model with the product as a competitive inhibitor and oxygen as an uncompetitive inhibitor was the most appropriate to explain the reaction kinetics. The values of the inhibition constants calculated from the model were 0.0032 mmol L−1 for Km (Michaelis–Menten constant related to oxygen), 0.023 mmol L−1 for Kmc (constant for competitive inhibition due to the product), 1.630 mmol L−1 for Kmu (constant for uncompetitive inhibition due to oxygen) and 1.77 × 10−4 mmol L−1 s−1 for Vmax (maximum reaction rate). The results indicate that superatmospheric oxygen concentrations could be effective in preventing enzymatic browning by PPO. Copyright © 2006 Society of Chemical Industry
Distribution of 127 edible plant species for antioxidant activities by two assays
Authors: Yang Ray‐Yu , Tsou Samson CS , Lee Tung‐Ching , Wu Wan‐Jan , Hanson Peter M , Kuo George , Engle Liwayway M , Lai Po‐Yung 
Published: September 2006

AbstractEpidemiological studies have demonstrated the protective effects of fruit and vegetable consumption on human health. A total of 150 edible plants representing 127 species were evaluated for Trolox equivalent antioxidant capacity (TEAC) and superoxide scavenging (SOS) activity. Distributions of vegetables for TEAC and SOS were not continuous but highly skewed. TEAC values on a dry weight basis ranged from 0 to 2105 µmol TE g−1 and SOS values ranged from 0 to 6206 µmol ascorbate equivalent (AE) g−1. The majority of vegetables clustered within 200 µmol TE g−1 and 400 µmol AE g−1. Vegetable species were grouped into six classes after natural logarithm transformation of TEAC and SOS values. Most highly consumed vegetables fell in the very low to medium classes. Species in the very high class for both TEAC and SOS included leaves of Cedrela sinensis (Chinese cedar), Oroxylum indicum (Damocles tree), Cassia siamea (cassod tree) and Cassia tora (sickle senna). Edible plants high in antioxidant activity (AOA) were mostly perennial and underutilised crops, while commonly consumed vegetables were generally low in AOA. There is great potential to increase dietary antioxidants and improve human health through consumption of diverse vegetable species, especially those high in AOA. Copyright © 2006 Society of Chemical Industry
Determination of amphetamines in human urine by liquid chromatography with fluorimetric detection using a solid‐phase extraction procedure
Authors: Bugamelli Francesca , Mandrioli Roberto , Cavallini Annalisa , Baccini Cesare , Conti Matteo , Raggi Maria Augusta 
Published: September 2006

AbstractA precise and feasible HPLC method has been developed for the analysis of amphetamine (AMPH), methamphetamine (MAMPH) and methylenedioxymethamphetamine (MDMA, ecstasy) in human urine. A chromatographic run on a C8 Genesis (150 mm×4.6 mm, 5 μm) column maintained at 30°C lasts about 17 min, using a mobile phase composed of ACN (12%) and a pH 2.5 phosphate buffer (88%) containing 0.3% triethylamine. Mirtazapine was used as the internal standard. Good linearity was found in the 100–2000 ng/mL concentration range for AMPH and MAMPH and in the 12–2000 ng/mL concentration range for MDMA. The pretreatment of urine samples was carried out by means of a careful SPE procedure on C2 cartridges. The extraction yields were very satisfactory for all analytes, with average values greater than 97%. The leading conditions allowed the determination of AMPH, MAMPH and MDMA with satisfactory precision and accuracy. The method has been successfully applied to the determination of the analytes in urine of AMPH users.
Continuous dopaminergic stimulation: Is it the answer to the motor complications of Levodopa?
Authors: Nutt John G. 
Published: September 2006

AbstractContinuous dopaminergic stimulation (CDS) is a treatment strategy hypothesized to avoid or reduce the motor complications of long‐term levodopa therapy, motor fluctuations, and dyskinesia, by preventing or reversing sensitization induced by pulsatile dopaminergic stimulation. The CDS hypothesis is itself based on several hypotheses. First, tonic dopaminergic stimulation is physiological. Second, sensitization is undesirable and should be reversed. Third, reduction of off time and dyskinesia can be induced simultaneously. Finally, clinical studies substantiate the CDS hypothesis. The evidence for these hypotheses is reviewed, and the need for randomized clinical trials that rigorously test the CDS hypothesis is emphasized. © 2006 Movement Disorder Society
Metric attributes of the unified Parkinson's disease rating scale 3.0 battery: Part II, construct and content validity
Authors: Forjaz Maria João , Martinez‐Martin Pablo 
Published: September 2006

AbstractThis article is the second of a two‐part series concerning the metric properties of the following three Parkinson's disease (PD) scales: modified Hoehn and Yahr staging (H&Y), Schwab and England (S&E), and Unified Parkinson's Disease Rating Scale (UPDRS) 3.0. Part II focuses on construct and content validity. To assess construct validity, a sample of 1,136 PD patients completed the above‐mentioned PD scales. Correlation coefficients between measures of disability and dysfunction [S&E, UPDRS Activities of Daily Living (ADL), and UPDRS Motor Examination] were |r| = 0.69–0.77, indicating good convergent validity. Results showed that the S&E (F(5,945) = 193.47; P < 0.0001) and UPDRS subscales discriminated between modified H&Y stages (F(20,2784) = 25.28; P < 0.001). A panel of 12 to 13 international experts rated the relevance of the scales and items. This enabled the scales' content validity index to be calculated, which ranged from 41.7% (UPDRS Mentation) to 83.3% (UPDRS Motor Examination). In conclusion, while the modified H&Y, S&E, and UPDRS displayed satisfactory construct validity, the content validity of all scales except UPDRS Motor Examination failed to attain adequate standards. © 2006 Movement Disorder Society
Developments in neuroacanthocytosis: Expanding the spectrum of choreatic syndromes
Authors: Walker Ruth H. , Danek Adrian , Dobson‐Stone Carol , Guerrini Renzo , Jung Hans H. , Lafontaine Anne‐Louise , Rampoldi Luca , Tison François , Andermann Eva 
Published: September 2006

AbstractAs with other neurodegenerative disorders, research into the group of diseases known under the umbrella term of “neuroacanthocytosis” has greatly benefited from the identification of causative genes. The distinct and unifying aspect of these disorders is the presence of thorny deformations of circulating erythrocytes. This may be due to abnormal properties of red cell membranes, which could lead to insights into mech‐ anisms of neurodegeneration. Research approaches in this field, in addition to examining functions and protein interactions of the affected proteins with particular respect to neurons, have also drawn upon the expertise of hematologists and red cell membrane biologists. In this article, recent developments in the field are presented. © 2006 Movement Disorder Society
Exploring the limits of RF shimming for high‐field MRI of the human head
Authors: Mao Weihua , Smith Michael B. , Collins Christopher M. 
Published: September 2006

AbstractSeveral methods have been proposed for overcoming the effects of radiofrequency (RF) magnetic field inhomogeneity in high‐field MRI. Some of these methods rely at least in part on the ability to independently control magnitude and phase of different drives in either one multielement RF coil or in different RF coils in a transmit array. The adjustment of these drive magnitudes and phases alone to create uniform RF magnetic (B1) fields has been called RF shimming, and has certain limits at every frequency as dictated by possible solutions to Maxwell's equations. Here we use numerical calculations to explore the limits of RF shimming in the human head. We found that a 16‐element array can effectively shim a single slice at frequencies up to 600 MHz and the whole brain at up to 300 MHz, while an 80‐element array can shim the whole brain at up to 600 MHz. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Quantification of intravoxel velocity standard deviation and turbulence intensity by generalizing phase‐contrast MRI
Authors: Dyverfeldt Petter , Sigfridsson Andreas , Kvitting John‐Peder Escobar , Ebbers Tino 
Published: September 2006

AbstractTurbulent flow, characterized by velocity fluctuations, is a contributing factor to the pathogenesis of several cardiovascular diseases. A clinical noninvasive tool for assessing turbulence is lacking, however. It is well known that the occurrence of multiple spin velocities within a voxel during the influence of a magnetic gradient moment causes signal loss in phase‐contrast magnetic resonance imaging (PC‐MRI). In this paper a mathematical derivation of an expression for computing the standard deviation (SD) of the blood flow velocity distribution within a voxel is presented. The SD is obtained from the magnitude of PC‐MRI signals acquired with different first gradient moments. By exploiting the relation between the SD and turbulence intensity (TI), this method allows for quantitative studies of turbulence. For validation, the TI in an in vitro flow phantom was quantified, and the results compared favorably with previously published laser Doppler anemometry (LDA) results. This method has the potential to become an important tool for the noninvasive assessment of turbulence in the arterial tree. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Diffusional kurtosis imaging in the lung using hyperpolarized 3He
Authors: Trampel Robert , Jensen Jens H. , Lee Ray F. , Kamenetskiy Igor , McGuinness Georgeann , Johnson Glyn 
Published: September 2006

AbstractDiseases of the small airspaces represent an increasingly important health problem. Asthma is primarily a disease of airway dysfunction, while chronic obstructive pulmonary disease (COPD) is associated with abnormalities in both the small airways and the alveoli. Conventional diffusion magnetic resonance imaging (MRI) of hyperpolarized noble gases, because of the short T2* of the gas, is only capable of monitoring diffusion over short times and hence only short distances. Diffusion imaging is therefore only sensitive to changes in small structures of the lung (primarily the alveoli), and will not adequately interrogate diffusion along the longitudinal axes of bronchi and bronchioles. In this communication we present a new method, termed diffusional kurtosis imaging (DKI), that is particularly sensitive to diffusion over longer distances. DKI may therefore be more sensitive to abnormalities in the bronchioles and bronchi than conventional diffusion imaging. Preliminary DKI measurements on healthy human subjects and one patient with symptoms suggestive of small airway disease are presented. Although the apparent diffusion coefficient (ADC) in the patient was similar to that in the normal controls, diffusional kurtosis was markedly reduced. This suggests that DKI measurements may be useful for assessing diseases of the small airways. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Stabilized updated Lagrangian corrected SPH for explicit dynamic problems
Authors: Vidal Y. , Bonet J. , Huerta A. 
Published: September 2006

Abstract
Smooth particle hydrodynamics with a total Lagrangian formulation are, in general, more robust than finite elements for large distortion problems. Nevertheless, updating the reference configuration may still be necessary in some problems involving extremely large distortions. However, as discussed here, a standard updated formulation suffers the presence of zero‐energy modes that are activated and may completely spoil the solution. It is important to note that, unlike an Eulerian formulation, the updated Lagrangian does not present tension instability but only zero‐energy modes. Here a stabilization technique is incorporated to the updated formulation to obtain an improved method without any mechanisms and which is capable to solve problems with extremely large distortions. Copyright © 2006 John Wiley & Sons, Ltd.