bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential subcellular distribution of glucose transporters GLUT1–6 and GLUT9 in human cancer: Ultrastructural localization of GLUT1 and GLUT5 in breast tumor tissues
Authors: Godoy Alejandro , Ulloa Viviana , Rodríguez Federico , Reinicke Karin , Yañez Alejandro J. , García María de los Angeles , Medina Rodolfo A. , Carrasco Mónica , Barberis Sofía , Castro Tamara , Martínez Fernando , Koch Ximena , Vera Juan Carlos , Poblete María Teresa , Figueroa Carlos D. , Peruzzo Bruno , Pérez Fernando , Nualart Francisco
Published: March 2006

It has been proposed that the enhanced metabolic activity of tumor cells is accompanied by an increased expression of facilitative hexose transporters (GLUTs). However, a previous immunohistochemical analysis of GLUT1 expression in 154 malignant human neoplasms failed to detect the GLUT1 isoform in 87 tumors. We used 146 normal human tissues and 215 tumor samples to reassess GLUT1 expression. A similar number of samples were used to compare the expression of GLUT2–6 and 9. The classical expression of GLUT1–5 in different normal human tissues was confirmed, however, we were unable to detect GLUT2 in human pancreatic islet cells. GLUT6 was principally detected in testis germinal cells and GLUT9 was localized in kidney, liver, heart, and adrenal. In tumor samples, GLUT1, 2, and 5 were the main transporters detected. GLUT1 was the most widely expressed transporter, however, 42% of the samples had very low‐to‐negative expression levels. GLUT2 was detected in 31% of the samples, being mainly expressed in breast, colon, and liver carcinoma. GLUT5 was detected in 27% of breast and colon adenocarcinoma, liver carcinoma, lymphomas, and testis seminoma samples. In situ RT‐PCR and ultrastructural immunohistochemistry confirmed GLUT5 expression in breast cancer. GLUT6 and 9 are not clearly over‐expressed in human cancer. The extensive expression of GLUT2 and 5 (glucose/fructose and fructose transporters, respectively) in malignant human tissues indicates that fructose may be a good energy substrate in tumor cells. Our functional data obtained in vitro in different tumor cells support this hypothesis. Additionally, these results suggest that fructose uptake could be used for positron emission tomography imaging and, may possibly represent a novel target for the development of therapeutic agents in different human cancers. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
A facile synthesis of [14C]pyrithiobac‐sodium
Authors: Ravi S. , Mathew K. M. , Padmanabhan D. , Unny V. K. P. , Sivaprasad N.
Published: March 2006

Condensation of thiourea 1 with diethyl malonate 2 in the presence of sodium methoxide furnished 4,6‐dihydroxy‐2‐mercaptopyrimidine 3. Compound 3 on methylation with diazomethane followed by oxidation with H5IO6/CrO3 in ethyl acetate gave 4,6‐dimethoxy‐2‐methylsulphonylpyrimidine 5. Compound 5 on condensation with 2‐mercapto‐6‐chlorobenzoic acid in the presence of a phase transfer catalyst, tetrabutylammonium bromide and sodium carbonate gave the title compound – pyrithiobac‐sodium 6 with an overall yield of > 35% starting from thiourea. Following the above standardized procedure, using [14C]‐thiourea in lieu of thiourea, 14C labelled product 6, was synthesized with an overall radiochemical yield > 30% (with respect to [14C]‐thiourea) for further evaluations of environmental fate of 6, in soils and plants. Copyright © 2006 John Wiley & Sons, Ltd.
Calculation of cerebral perfusion parameters using regional arterial input functions identified by factor analysis
Authors: Knutsson Linda , Larsson Elna‐Marie , Thilmann Oliver , Ståhlberg Freddy , Wirestam Ronnie
Published: March 2006

Purpose

To calculate regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and regional mean transit time (rMTT) accurately, an arterial input function (AIF) is required. In this study we identified a number of AIFs using factor analysis of dynamic studies (FADS), and performed the cerebral perfusion calculation pixel by pixel using the AIF that was located geometrically closest to a certain voxel.

Materials and Methods

To verify the robustness of the method, simulated images were generated in which dispersion or delay was added in some arteries and in the corresponding cerebral gray matter (GM), white matter (WM), and ischemic tissue. Thereafter, AIFs were determined using the FADS method and simulations were performed using different signal‐to‐noise ratios (SNRs). Simulations were also carried out using an AIF from a single pixel that was manually selected. In vivo results were obtained from normal volunteers and patients.

Results

The FADS method reduced the underestimation of rCBF due to dispersion or delay that often occurs when only one AIF represents the entire brain.

Conclusion

This study indicates that the use of FADS and the nearest‐AIF method is preferable to manual selection of one single AIF. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
A pulse sequence for rapid in vivo spin‐locked MRI
Authors: Borthakur Arijitt , Hulvershorn Justin , Gualtieri Eugene , Wheaton Andrew J. , Charagundla Sridhar , Elliott Mark A. , Reddy Ravinder
Published: March 2006

Purpose

To develop a novel pulse sequence called spin‐locked echo planar imaging (EPI), or (SLEPI), to perform rapid T1ρ‐weighted MRI.

Materials and Methods

SLEPI images were used to calculate T1ρ maps in two healthy volunteers imaged on a 1.5‐T Sonata Siemens MRI scanner. The head and extremity coils were used for imaging the brain and blood in the popliteal artery, respectively.

Results

SLEPI‐measured T1ρ was 83 msec and 103 msec in white (WM) and gray matter (GM), respectively, 584 msec in cerebrospinal fluid (CSF), and was similar to values obtained with the less time‐efficient sequence based on a turbo spin‐echo readout. T1ρ was 183 msec in arterial blood at a spin‐lock (SL) amplitude of 500 Hz.

Conclusion

We demonstrate the feasibility of the SLEPI pulse sequence to perform rapid T1ρ MRI. The sequence produced images of higher quality than a gradient‐echo EPI sequence for the same contrast evolution times. We also discuss applications and limitations of the pulse sequence. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Effect of contrast enhancement on the measurement of carotid arterial lumen and wall volume using MRI
Authors: Phan Binh An P. , Chu Baocheng , Kerwin William S. , Xu Dongxiang , Yuan Chun , Hatsukami Thomas , Zhao Xue‐Qiao
Published: March 2006

Purpose

To investigate whether gadolinium (Gd)‐based contrast enhancement (CE) affects high‐resolution magnetic resonance imaging (MRI) measurements of carotid arterial wall volume.

Materials and Methods

The common carotid artery (CCA), bifurcation, and internal carotid artery (ICA) of 50 consecutive patients were imaged using 1.5T MRI. T1‐weighted (T1W) images were obtained before and after Gd administration. Pre‐ and post‐CE measurements were compared among different arterial locations of the CCA, bifurcation, and ICA, and among different atherosclerotic lesion types.

Results

In comparison to pre‐CE T1W images, post‐CE images showed an increase in the apparent wall volume measurement of 28.2% (108.7 mm3 vs. 84.7 mm3, P < 0.001). The post‐CE measurement increases in wall volume for the CCA, bifurcation, and ICA were 26.7%, 29.2%, and 28.0%, respectively.

Conclusion

Gd CE causes a significant increase in the apparent volume of the carotid wall throughout multiple carotid artery locations, which may be associated with improved visibility or neovascularization. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Breast lesion analysis of shape technique: Semiautomated vs. manual morphological description
Authors: Liney Gary P. , Sreenivas Muthyala , Gibbs Peter , Garcia‐Alvarez Roberto , Turnbull Lindsay W.
Published: March 2006

Purpose

To investigate the efficacy of an automated method of shape measurement for improving the discrimination of benign and malignant breast lesions.

Materials and Methods

A total of 47 breast lesions (32 malignant and 15 benign) were examined using a 1.5 Tesla system. Regions of interest (ROIs) were manually drawn and extracted from high‐resolution, fat‐suppressed, postcontrast images, or were extracted with the use of a semiautomated computer algorithm. Shape parameters (i.e., complexity, convexity, circularity, and degree of elongation) were determined to assess whether they could be used to discriminate breast lesions.

Results

Convexity differed significantly between the benign and malignant groups for both ROI methods. In addition, the semiautomated method demonstrated significantly different values of complexity.

Conclusion

This work demonstrates the usefulness of several shape descriptors for characterizing breast lesions, and shows that the automated method of analysis improves the discrimination and standardization of data. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Focal liver lesions: Breathhold gradient‐ and spin‐echo T2‐weighted imaging for detection and characterization
Authors: Yoshikawa Takeshi , Mitchell Donald G. , Hirota Shozo , Ohno Yoshiharu , Yoshigi Jun , Maeda Takaki , Fujii Masahiko , Sugimura Kazuro
Published: March 2006

Purpose

To evaluate breathhold gradient‐ and spin‐echo (GRASE) T2‐weighted imaging for the detection and characterization of focal liver lesions.

Materials and Methods

Two GRASE sequences with different echo times (75 and 90 msec, GRASE75 and GRASE90) were compared with respiratory‐triggered fast spin‐echo (SE) and breathhold fast SE in 64 patients with 103 malignant and 51 benign lesions. Compared with respiratory‐triggered and breathhold fast SE, GRASE reduced scan time by 77% to 82% and 21% to 27%, respectively. Two independent readers evaluated image quality and reviewed 504 liver segments on a segment‐by‐segment basis. Observer performance was evaluated with receiver operating characteristic (ROC) curve analysis. The signal‐to‐noise ratio (SNR) of liver and spleen, and lesion‐to‐liver contrast‐to‐noise ratio (CNR) were also measured.

Results

The overall quality of the GRASE images was higher than that of the respiratory‐triggered and breathhold fast SE images, although signal inhomogeneities were more frequently observed with GRASE. No significant difference in the values of the area under the ROC curve (Az) for malignant lesion detection was found. The mean SNR and CNR were highest for respiratory‐triggered fast SE.

Conclusion

T2‐weighted breathhold GRASE has the potential to provide faster liver imaging. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Chronic vitamin D3treatment protects against neurotoxicity by glutamate in association with upregulation of vitamin D receptor mRNA expression in cultured rat cortical neurons
Authors: Taniura Hideo , Ito Minoru , Sanada Noriko , Kuramoto Nobuyuki , Ohno Yu , Nakamichi Noritaka , Yoneda Yukio
Published: March 2006

The vitamin D receptor (VDR) is believed to mediate different biologic actions of vitamin D3, an active metabolite of vitamin D, through regulation of gene expression after binding to specific DNA‐response element (VDRE) on target genes. To further understand roles of both vitamin D3and VDR in the central nervous system, we examined VDRE binding in nuclear extracts prepared from discrete rat brain regions and cultured rat cortical neurons by electrophoretic mobility shift assay. The highest activity of VDRE binding was found in the cerebellum among other brain regions examined, but sequence specific by taking into consideration the efficient competition with excess unlabeled VDRE but not with mutated VDRE. On in situ hybridization analysis, cells stained for VDR mRNA were abundant in neuron‐enriched areas of cerebral cortex, hippocampus and cerebellar cortex in the mouse brain. Chronic treatment of vitamin D3increased the expression of microtubule‐associated protein‐2, growth‐associated protein‐43 and synapsin‐1 in cultured rat cortical neurons, suggesting a trophic role of vitamin D3in differentiation and maturation of neurons. Neuronal cell death by brief glutamate exposure was significantly protected in cultured cortical neurons chronically treated with vitamin D3. Parallel studies showed that VDR mRNA was significantly upregulated 12–24 hr after brief glutamate exposure in cultured neurons chronically treated with vitamin D3, but not in those with vehicle alone. Our results suggest that vitamin D3may play a role in mechanisms relevant to protective properties against the neurotoxicity of glutamate through upregulation of VDR expression in cultured rat cortical neurons. © 2006 Wiley‐Liss, Inc.
A BAD link to mitochondrial cell death in the cochlea of mice with noise‐induced hearing loss
Authors: Vicente‐Torres M. Angeles , Schacht Jochen
Published: March 2006

Acoustic overstimulation induces calcium overload and activation of mitochondria‐mediated cell death pathways in outer hair cells (OHC) of the cochlea. However, it is not known whether these events are interrelated or independent. We have recently reported that the calcium‐dependent phosphatase calcineurin is activated in OHC following noise exposure and now postulate that calcium overload triggers mitochondria‐mediated death pathways through activation of Bcl‐2‐associated death promoter (BAD) by calcineurin. CBA/J mice were exposed to broadband noise (2–20 kHz), causing a permanent threshold shift of about 40 dB at 12 and 20 kHz, corresponding to damage in the middle and basal turns of the cochlea. Loss of OHC in the basal region was evident in surface preparations. BAD immunostaining in control animals had a cytoplasmic distribution in the cells of the organ of Corti. Five hours after acoustic overstimulation, mitochondria and BAD redistributed to the perinuclear region of OHC in the basal and middle turns but not in the apical turn. The nonapoptotic phospho‐BAD (Ser 112) was up‐regulated in cells undamaged by noise (supporting cells and inner hair cells) but not in OHC. These data establish a connection between calcium overload and mitochondria‐mediated death pathways in OHC and also suggest a dual role for BAD. The translocation of BAD to the mitochondria in degenerating cells is indicative of the activation of its proapoptotic capacity, whereas up‐regulation of phospho‐BAD is consistent with a nonapoptotic role of BAD in less vulnerable cells. © 2006 Wiley‐Liss, Inc.
Mechanistic Differences in Degradation of Polystyrene and Polystyrene‐Clay Nanocomposite: Thermal and Thermo‐Oxidative Degradation
Authors: Chen Kai , Vyazovkin Sergey
Published: March 2006

Summary: A conceptual model for degradation of polymer‐clay brushes is discussed. The model predicts enhancement of inter‐molecular reactions and slowing down of molecular mobility. A polystyrene (PS)‐clay brush system is experimentally compared with virgin PS under the conditions of thermal and thermo‐oxidative degradation. GC‐MS and TGA‐FTIR analysis of the gas phase degradation products of PS‐clay composite confirm a dramatic increase in the yield of inter‐molecular reaction product, such as α‐methylstyrene. Combining DSC measurements with FTIR analysis of condensed phase thermo‐oxidative degradation of PS‐clay suggests that PS‐clay nanocomposite is more stable to oxidation, however, oxidation products tend to accumulate in it because of slowing down diffusion of oxidation products.

Gas phase IR spectra from the TGA‐FTIR study of virgin PS and PS‐clay for different stages of degradation.

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Gas phase IR spectra from the TGA‐FTIR study of virgin PS and PS‐clay for different stages of degradation.
pH‐Responsive PEG‐Poly(β‐amino ester) Block Copolymer Micelles with a Sharp Transition
Authors: Kim Min Sang , Hwang Su Jong , Han Jong Kwon , Choi Eun Kyung , Park Heon Joo , Kim Jin Seok , Lee Doo Sung
Published: March 2006

Summary: A pH‐sensitive block copolymer is synthesized by step polymerization and its pH‐sensitive micellization‐demicellization behavior is studied. This polymer has a hydrophilic MPEG (shell) and hydrophobic but pH‐sensitive poly(β‐amino ester) (core), which can form a self‐assembled micelle. As confirmed by fluorescence spectroscopy and dynamic light scattering (DLS), this polymer shows a sharp pH‐sensitive micellization‐demicellization behavior. It is confirmed that the pH sensitivity is affected by the molecular weight ratio between the MPEG and poly(β‐amino ester).

Plots of the intensity ratio I337/I334 (from pyrene excitation spectra): a) vs. pH for copolymer samples and b) vs. log (concentration) for M1.

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Plots of the intensity ratio I337/I334 (from pyrene excitation spectra): a) vs. pH for copolymer samples and b) vs. log (concentration) for M1.
Severe acute respiratory syndrome coronavirus entry into host cells: Opportunities for therapeutic intervention
Authors: Yeung Kap‐Sun , Yamanaka Gregory A. , Meanwell Nicholas A.
Published: March 2006

A novel human coronavirus (CoV) has been identified as the etiological agent that caused the severe acute respiratory syndrome (SARS) outbreak in 2003. The spike (S) protein of this virus is a type I surface glycoprotein that mediates binding of the virus to the host receptor and the subsequent fusion between the viral and host membranes. Because of its critical role in viral entry, the S protein is an important target for the development of anti‐SARS CoV therapeutics and prophylactics. This article reviews the structure and function of the SARS CoV S protein in the context of its role in virus entry. Topics that are discussed include: the interaction between the S1 domain of the SARS spike protein and the cellular receptor, angiotensin converting enzyme 2 (ACE2), and the structural features of the ectodomain of ACE2; the antigenic determinants presented by the S protein and the nature of neutralizing monoclonal antibodies that are elicited in vivo; the structure of the 4,3‐hydrophobic heptad repeats HR1 and HR2 of the S2 domain and their interaction to form a six‐helical bundle during the final stages of fusion. Opportunities for the design and development of anti‐SARS agents based on the inhibition of receptor binding, the therapeutic uses of S‐directed monoclonal antibodies and inhibitors of HR1–HR2 complex formation are presented. © 2006 Wiley Periodicals, Inc. Med Res Rev, 26, No. 4, 414–433, 2006
Characterization of bacteriocins from two Lactococcus lactis subsp. lactis isolates
Authors: Akçelik Oya , Tükel Çaǧla , Özcengiz Gülay , Akçelik Mustafa
Published: March 2006

In this study, bacteriocins from two Lactococcus lactis subsp. lactis isolates from raw milk samples in Turkey designated OC1 and OC2, respectively, were characterized and identified. The activity spectra of the bacteriocins were determined by using different indicator bacteria including Listeria, Bacillus and Staphylococcus spp. Bacteriocins were tested for their sensitivity to different enzymes, heat treatments and pH values. Loss of bacteriocin activities after α‐amylase treatment suggested that they form aggregates with carbohydrates. Molecular masses of the purified bacteriocins were determined by SDS‐PAGE. PCR amplification was carried out with specific primers for the detection of their structural genes. As a result of these studies, the two bacteriocins were characterized as nisin and lacticin 481, respectively. Examination of plasmid contents of the isolates and the results of plasmid curing and conjugation experiments showed that in L. lactis subsp. lactis OC1 strain the 39.7‐kb plasmid is responsible for nisin production, lactose fermentation and proteolytic activity, whereas the 16.0‐kb plasmid is responsible for lacticin 481 production and lactose fermentation in L. lactis subsp. lactis OC2 strain.
Expanded bed adsorption as a fast technique for the large‐scale purification of the complete isoform pool of Ber e 1, the major allergen from Brazil nuts
Authors: van Boxtel Evelien L. , van Koningsveld Gerrit A. , Koppelman Stef J. , van den Broek Lambertus A. M. , Voragen Alfons G. J. , Gruppen Harry
Published: March 2006

A new, fast, large‐scale purification method for Ber e 1, the major allergen from Brazil nuts, using expanded bed adsorption (EBA) chromatography, is presented. Using EBA, crude extracts can be applied to a fluidized column, which allows the unhindered passage of particulate impurities, thereby avoiding time‐consuming centrifugation or filtration steps. With this new purification method, 2.8 g of Ber e 1 was obtained from 85 g defatted Brazil nut meal, essentially within 1 day. Various structural as well as immunochemical characteristics of the purified protein were determined, and compared to those of Ber e 1 purified using conventional chromatographic techniques. The complete pool of Ber e 1 isoforms was collected using EBA. The most abundant isoforms were observed to have pI around 8 and heterogeneity was observed in both the large and the small subunit of the heterodimeric protein. Ber e 1 has a highly ordered secondary structure. No apparent differences in immune reactivity were observed between EBA purified Ber e 1 and conventionally purified Ber e 1, using IgE‐binding experiments. Thus, using EBA, Ber e 1 can be purified fast and on gram‐scale, while having purity equal to that of conventionally purified Ber e 1.
Identification of nobiletin metabolites in mouse urine
Authors: Li Shiming , Wang Zhenyu , Sang Shengmin , Huang Mou‐Tuan , Ho Chi‐Tang
Published: March 2006

Nobiletin, a major component of citrus polymethoxyflavones, has many potential significant health benefits. While the biological activities of nobiletin have been widely reported, its in vitro and in vivo metabolic fate has been rarely studied. To explore the biotransformation mechanism of nobiletin we conducted an investigation into its metabolic profile in mouse urine, by various analytical techniques. Due to sample amount limitations for isolating and characterizing an individual metabolite, two possible nobiletin metabolites were prepared in a similar multi‐step organic synthetic route: 3′‐hydroxy‐5,6,7,8,4′‐pentamethoxyflavone (3′‐demethylnobiletin) and 4′‐hydroxy‐5,6,7,8,3′‐pentamethoxyflavone (4′‐demethylnobiletin). Normal phase (silica gel) and C18 reverse phase chromatography, as well as liquid chromatography‐mass spectrometry‐mass spectrometry, were employed in the separation of 3′‐demethylnobiletin and 4′‐demethylnobiletin, however, without success due to the structural similarities of these mono‐demethylated nobiletins. Using a chiral packed column eluted under supercritical fluid chromatography (SFC) conditions, a clear separation was achieved. Thus, by comparing the SFC profiles of metabolite mixtures with the synthesized standard compounds, the major nobiletin metabolite of mouse urine is identified as 4′‐demethylnobiletin, whereas 3′‐demethylnobiletin is a minor metabolite. In this study, the concentration of 4′‐demethylnobiletin in mouse urine is 28.9 μg/mL.
Survey of the occurrence of Aflatoxin M1 in ovine milk by HPLC and its confirmation by MS
Authors: Bognanno Matteo , La Fauci Luca , Ritieni Alberto , Tafuri Alessio , De Lorenzo Antonino , Micari Pietro , Di Renzo Laura , Ciappellano Salvatore , Sarullo Virginia , Galvano Fabio
Published: March 2006

During the period of October–July 2000, 240 samples of dairy ewes milk, obtained from farms of Enna (Sicily, Italy), were checked for Aflatoxin M1 (AFM1) by HPLC using a fluorimetric detector. The limit of detection and the limit of quantification were 250 ng/L for AFM1. All the positive milk samples for AFM1 were confirmed by LC‐MS. AFM1 was detected in 81% of milk samples, ranging from 2 to 108 ng/L. Three samples were over the legal limits (50 ng/L). Mean contamination of samples obtained from stabulated ewes was higher than that from grazing ewes (35.27 vs. 12.47 ng/L). Furthermore, samples collected in the period September–October showed higher contamination than samples collected during the other months (42.68 vs. 10.55 ng/L). Both differences are related to the administration of compound feed. Based on current toxicological knowledge we concluded that the AFM1 contamination levels recorded in ewe milk did not present a serious human health hazard. However, as ewe milk is exclusively used to produce cheese due to its higher protein content, and also considering the preferential binding of AFM1 to casein during coagulation of milk, a potentially high concentration effect could occur, thus the surveillance of contamination levels should be more continuous and widespread.
New Monascus metabolites: Structure elucidation and toxicological properties studied with immortalized human kidney epithelial cells
Authors: Knecht Anja , Cramer Benedict , Humpf Hans‐Ulrich
Published: March 2006

Monascus sp. are used for the production of red yeast rice, which has been applied in Asian food and medicine for centuries. The fungi form several secondary metabolites, among others the monascopyridines A and B. We have now detected two new monascopyridines (named C and D) with similar UV absorption spectra and maxima at 306–307 nm in red rice fermented with M. purpureus. The new monascopyridines have the same chromophores as the already known and differ in a missing γ‐lactone ring only. Monascopyridine C has a hexanoyl side chain, whereas monascopyridine D is the higher homologue with an octanoyl side chain. The toxicological properties of monascopyridines were studied using immortalized human kidney epithelial cells, displaying cytotoxic effects in micromolar concentrations with median effective concentration values between 20.7 and 43.2 μmol/L, depending on the compound and method used. The monascopyridines C and D did not induce apoptosis. However, they caused a rise of the mitotic index from 3.21 ± 0.27% (control) to maximum 8.14 ± 0.89% (monascopyridine D) by an accumulation of cells in the metaphase with a simultaneous decrease of cells in the ana‐ and telophase. Monascopyridine‐induced metaphase arrest is caused by a partial or complete loss of the spindle apparatus as indicated by the occurrence of abnormal metaphases and immunological staining of α‐tubulin. These effects are indicating an aneuploidic potential and therefore the monascopyridines C and D might contribute to tumor formations.
Stable isotope dilution analysis of the Fusarium mycotoxins deoxynivalenol and 3‐acetyldeoxynivalenol
Authors: Bretz Michael , Beyer Marita , Cramer Benedikt , Humpf Hans‐Ulrich
Published: March 2006

Trichothecenes are secondary metabolites produced by several fungi of the Fusarium genus during their growth period. They inhibit protein biosynthesis in eukaryotic cells resulting in numerous toxic effects such as diarrhea, vomiting, and gastro‐intestinal inflammation. Considering its occurrence in food and feedstuff, deoxynivalenol (DON) is one of the most important trichothecenes. We report the synthesis of stable isotope labeled 15‐d1‐deoxynivalenol (15‐d1‐DON) from its natural precursor 3‐acetyldeoxynivalenol (3‐AcDON) as starting material. Furthermore, a method for the analysis of DON and 3‐AcDON using HPLC‐MS/MS with stable isotope labeled 15‐d1‐DON and 3‐d3‐AcDON as internal standards has been developed. In total, 18 cereal product samples were analyzed with contamination levels ranging from 10–301 μg/kg for DON and 5–14 μg/kg for 3‐AcDON. This is the first report of an isotope dilution MS method for the analysis of type B‐trichothecenes.
A new solid phase extraction clean‐up method for the determination of 12 type A and B trichothecenes in cereals and cereal‐based food by LC‐MS/MS
Authors: Klötzel Marianna , Lauber Uwe , Humpf Hans‐Ulrich
Published: March 2006

A new reliable and cost‐efficient solid phase extraction‐based clean‐up method for the determination of 12 type A and B trichothecenes [deoxynivalenol (DON), nivalenol, 3‐acetyldeoxynivalenol, 15‐acetyldeoxynivalenol, fusarenon‐X, T‐2 toxin, HT‐2 toxin, neosolaniol, monoacetoxy‐scirpenol, diacetoxyscirpenol, T‐2 triol and T‐2 tetraol] in cereals and cereal‐based food is presented. Furthermore, the suitability for the simultaneous determination of zearalenone is examined. Toxins were extracted from cereal samples using ACN/water (80/20, v/v), purified by means of a new Bond Elut Mycotoxin® column and analyzed via liquid chromatography‐electrospray ionization tandem mass spectrometry. Limits of detection were calculated for the matrix wheat and ranged from 0.3 to 5 ng/g, depending on the toxin. Average recovery rates for the tested compounds in seven cereal‐based matrices have been determined ranging from 65 to 104%. The relative standard deviations of the complete method ranged from 2.67 (DON, wheat) to 20.0% (T‐2 toxin, oats).
The L513S polymorphism in medium‐chain acyl‐CoA synthetase 2 (MACS2) is associated with risk factors of the metabolic syndrome in a Caucasian study population
Authors: Lindner Inka , Rubin Diana , Helwig Ulf , Nitz Inke , Hampe Jochen , Schreiber Stefan , Schrezenmeir Jürgen , Döring Frank
Published: March 2006

Enzymes of the medium‐chain acyl‐CoA synthetase (MACS) family catalyze the ligation of medium chain fatty acids with CoA to produce medium‐chain‐acyl‐CoA. At least four members of the MACS gene family are clustered on human chromosome 16p12. Association studies in the Japanese Suita cohort of MACS polymorphisms and various phenotypes revealed the contribution of the Leu513Ser polymorphism in MACS2 to multiple risk factors of the metabolic syndrome. Here, we investigated the association between this polymorphism and different risk factors in the Caucasian Metabolic Intervention Cohort Kiel. Seven hundred and sixteen male subjects aged 45–65 years were recruited for a standard oral glucose tolerance test and the postprandial assessment of metabolic parameters after an oral metabolic tolerance test (oMTT; 1017 kcal, 51.6% fat, 29.6% carbohydrates, 11.9% protein). The MACS2 Leu513Ser polymorphism was determined by TaqMan‐Assay in 705 subjects. Postprandial triglyceride levels following oMTT [area under the curve (AUC)] were significantly higher in subjects carrying the Ser allele compared to subjects homozygous for the Leu allele (1690 ± 100 mg×h/dL ersus 1514 ± 39 mg×h/dL, p = 0.04). Significant differences between genotype groups were also found for fasting (108 ± 1.9 mg/dL versus 104 ± 0.66 mg/dL, p = 0.04) and postprandial (AUC 535 ± 11 versus 512 ± 4.0, p = 0.02) glucose levels as well as for high‐density‐lipoprotein, body mass index, waist circumference, systolic and diastolic blood pressure. Carriers of the Ser allele also show an increased risk of impaired glucose metabolism (OR: 1.48, 95% confidence interval: 0.98–2.27, p = 0.07), adiposity (1.8, 1.16–2.81, p = 0.01) and hypertension (1.5, 0.99–2.17, p = 0.06). In conclusion, our results suggest an involvement of the MACS2 Leu513Ser polymorphism in the development of the metabolic syndrome in Caucasian population. Additionally, the higher triglyceride and glucose levels after an oMTT support a possible functional impact of the polymorphism in vivo.
1H and 13C NMR spectral assignments of four dammarane triterpenoids from carnauba wax
Authors: de Brito Cysne Juliana , Braz‐Filho Raimundo , Assunção Marcus Vinícius , de Andrade Uchoa Daniel E. , Silveira Edilberto R. , Pessoa Otília Deusdênia L.
Published: March 2006

The phytochemical investigation of carnauba wax led to the isolation of three new dammarane triterpenoids 1, 2 and 4, together with the known triterpene 3. The structures of the new compounds were determined by 1D and 2D NMR spectroscopy and by comparison with published data for closely related compounds. Copyright © 2006 John Wiley & Sons, Ltd.
Determinants of epidermal nerve fiber density in normal individuals
Authors: Umapathi T. , Tan Wan Loo , Tan Nigel C. K. , Chan Yiong Huak
Published: March 2006

We studied the relationship between epidermal innervation and age, gender, height, and weight. Intraepidermal nerve fiber density (IENFD) of skin biopsies obtained from the proximal thigh and ankle of 84 normal individuals was quantified. A linear regression model was performed using IENFD at the thigh, IENFD at the ankle, and the thigh IENFD/ankle IENFD ratio, with age, gender, and height–weight interaction as predictors. An independent, negative correlation was found between age and IENFD at the ankle. No correlation was found between age and IENFD at the thigh. With increasing age the thigh IENFD/ankle IENFD ratio, a measure of the length‐dependent distal‐to‐proximal gradient of epidermal nerve density, increased significantly. Gender, height, and body weight did not independently influence IENFD at either site. In normal individuals, distal epidermal innervation decreases in a length‐dependent manner with advancing age. This must be considered when interpreting IENFD in disease states. Muscle Nerve, 2006
Influence of time of day on tendon compliance and estimations of voluntary activation levels
Authors: Pearson Stephen J. , Onambele Gladys N. L.
Published: March 2006

We investigated the importance of tendon stiffness on estimations of central activation capacity (CAC). Patella tendon–force elongation relationship, quadriceps torque, and response to 50‐μs, 100‐HZ electrical twitch doublets were studied at ∼8:00 A.M. and ∼6:00 P.M. in 8 healthy young men. Results show that in the evening, as compared with the morning, tendon stiffness decreased by 20.2 ± 9.5% (P = 0.03) and time to twitch peak (Ttp) increased by 55% (P = 0.04). Tendon stiffness and Ttp correlated significantly (r = 0.28, P < 0.05). Whereas the CAC, calculated as the ratio of force preceding the interpolated twitch (IT) to the total force at the peak of the IT, showed no change with time of day, calculations that used twitch ratios suggested CAC decrements (−10.3%, P = 0.03, unpotentiated; −10%, P = 0.02, potentiated ratio) in the evening. This study shows that CAC estimations are invalid when tendon properties are not taken into account, an error that would have important implications in a clinical setting. Muscle Nerve, 2006
Maximizing project cash availability
Authors: Szmerekovsky Joseph G. , Vairaktarakis George L.
Published: March 2006

Consider a project during the life cycle of which there are cash payouts and in‐flows. To better meet his financial commitments, the project owner would like to meet all deadlines without running out of cash. We show that the cash availability objective is similar to the total weighted flowtime used to measure work‐in‐progress performance in the scheduling and inventory control literatures. In this article we provide several specialized solution methods for the problem of minimizing total weighted flowtime in an arbitrary acyclic project network, subject to activity release times and due dates, where the activity weights may be positive or negative and represent cash in‐ and out‐flows. We describe the structure of an optimal solution and provide several efficient algorithms and their complexity based on mincost and maxflow formulations. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Interference temperature: a metric for dynamic spectrum utilization
Authors: Kolodzy Paul J.
Published: March 2006

Interference temperature has been proposed by the FCC as a metric for interference analysis. The purpose of the metric is to demystify and remove the subjective context that has been the basis of interference analysis within the regulatory agencies. The development of an interference metric is critical if more intensive, dynamic use of the spectrum is desired. There has been very little specified as to the origins, use, and challenges of an interference metric. This paper provides an introductory analysis of the interference temperature metric. Copyright © 2006 John Wiley & Sons, Ltd.
Outage performance of a hybrid DS/FH spread‐spectrum signal in an ISM band
Authors: Li Hanyu , Syed Mubashir , Yao Yu‐Dong
Published: March 2006

This paper develops an analytical model for characterizing the coexistence interference in the unlicensed industrial, scientific and medical (ISM) bands, based on radio frequency measurement results in the 2.4 GHz ISM band. The modeling approach presented here offers a simple methodology for profiling the interference from devices occupying a common spectrum. Outage performance using the interference model is exemplified through the analysis for a hybrid direct‐sequence frequency‐hopping spread‐spectrum signal. The work presented in this paper looks to provide insight by means of quantitative evaluation of signal outage in a coexistence environment that can be used for engineering design of applications for unlicensed bands as well as function as a tool in the development process for future spectrum management policy models. Copyright © 2006 John Wiley & Sons, Ltd.
Opportunities and challenges in software radio design for interference management
Authors: Bose Vanu
Published: March 2006

Interference management is a critical aspect of the design and deployment of any wireless network. Interference can reduce quality, deny service or significantly reduce the efficiency of spectrum use. Software radio holds the potential to increase the pace of innovation, flexibility and spectrum efficiency of wireless communications. Interference management is a critical aspect for devices and system design for any wireless system, and involves unique performance flexibility trade‐offs for software radio design. This paper provides a review of interference management techniques by looking at two representative communications systems: cellular networks and unlicensed wireless local area networks. These two systems are chosen since they are representative of two very different types of communications networks. Cellular systems typically operate in a licensed band and have separate frequencies for transmission and reception, while 802.11b operates in an unlicensed spectrum and utilizes the same band for transmission and reception. The paper starts with a review of the fundamental interference issues and an overview of software radio systems. Following that, for each interference issue, the approaches and constraints for each standard are reviewed and the opportunities and challenges for software radio design are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Detectable minimal residual disease before allogeneic hematopoietic stem cell transplantation predicts extremely poor prognosis in children with acute lymphoblastic leukemia
Authors: Sramkova Lucie , Muzikova Katerina , Fronkova Eva , Krejci Ondrej , Sedlacek Petr , Formankova Renata , Mejstrikova Ester , Stary Jan , Trka Jan
Published: March 2006

Background

The level of minimal residual disease (MRD) prior to allogeneic hematopoietic stem cell transplantation (HSCT) has been shown to be an independent prognostic factor for outcome of pediatric patients with high‐risk acute lymphoblastic leukemia (ALL). Retrospective studies which used (semi‐) quantitation of clone‐specific immunoglobulin/T‐cell receptor (Ig/TCR) rearrangements have documented the feasibility and practicality of this technique. This approach has also been disputed due to the occurrence of clonal evolution and generally high MRD levels prior to HSCT.

Procedure

In our prospective study, MRD before and after HSCT was monitored using quantitative real‐time PCR in a cohort of 36 children with ALL consecutively transplanted in our center between VIII/2000 and VII/2004.

Results

In 25 of 36 patients, MRD level prior HSCT was assessed. Seventeen patients were classified as MRD‐negative and eight were MRD‐positive up to 9 × 10−2. In MRD‐positive subgroup, seven events (six relapses) occurred post‐transplant in striking contrast to only one relapse in MRD‐negative subgroup (event‐free survival (EFS) log‐rank P < 0.0001). MRD proved to be the only significant prognostic factor in a multivariate analysis (P < 0.0001). Adoptive immunotherapy including donor lymphocyte infusions in patients with adverse dynamics of MRD after HSCT had only limited and/or temporary effect. Clonal evolution did not present a problem precluding MRD monitoring in any of patients suffering a post‐transplant relapse.

Conclusions

We show that MRD quantitation using clonal Ig/TCR rearrangements successfully assesses the risk in pediatric ALL patients undergoing allogeneic HSCT. As our ability to treat detectable MRD levels after HSCT is very limited, alternative strategies for MRD‐positive patients prior HSCT are necessary. Pediatr Blood Cancer 2007;48:93–100. © 2006 Wiley‐Liss, Inc.
Morphology and mechanical properties of polymer nanocomposites with a poly(hydroxy ether of bisphenol A) matrix
Authors: Gurmendi Urko , Eguiazabal Jose Ignacio , Nazabal Jon
Published: March 2006

The poly(hydroxy ether of bisphenol A) (phenoxy (Ph)) has been revealed as a polymeric matrix able to intercalate in, and partially exfoliate a commercial organically modified montmorillonite. Dispersion was attributed to chemical interactions between the Ph and the inorganic clay. A significant increase in the modulus of elasticity (33% with 3.8% montmorillonite (MMT) addition) was observed, together with an unusual increase in ductility attributed to surfactant migration, that should allow tailoring of the processing conditions to widen exfoliation. Ph‐based nanocomposites could be used as a nanostructured masterbatch for producing new polymer nanocomposites by mixing the masterbatch with the polymeric matrices that either miscibilize or are compatible with Ph. Copyright © 2006 Society of Chemical Industry
Preparation and characterization of unsaturated poly(ester‐imide) based on 1,4‐bis[2′‐trifluoromethyl‐4′‐(4″‐glycolformate)‐trimellitimidophenoxy]benzene
Authors: Li Haiyan , Wang Desheng , Fan Lin , Yang Shiyong
Published: March 2006

A novel diimidodialcohol monomer, 1,4‐bis[2′‐trifluoromethyl‐4′‐(4″‐glycolformate)‐ trimellitimidophenoxy]benzene (BGTB), was synthesized and characterized. It was reacted with isophthalic acid, maleic anhydride and propylene glycol to produce a novel unsaturated poly(ester‐imide) (BGTB‐UPEI) with imide and trifluoromethyl groups in the polymer backbone. The BGTB‐UPEI resin was diluted with reactive monomer (styrene) to give a low‐viscous poly(ester‐imide)/styrene (BGTB‐UPEI/St) mixed solution, which was then thermally cured to yield thermosetting BGTB‐UPEI/St composite. The effect of processing parameters such as the curing temperature and curing time, reactive monomer concentration and initiator amount on the curing reaction was systematically investigated. Experimental results indicated that the thermally cured BGTB‐UPEI/St composite exhibited much better thermal, mechanical, electrical insulating properties and chemical resistance than the standard unsaturated polyester/polystyrene composite. Copyright © 2006 Society of Chemical Industry
Gas‐phase olefin polymerization over supported metallocene/MAO catalysts: influence of support on activity and polydispersity
Authors: Hammawa Hassan , Wanke Sieghard E
Published: March 2006

Three catalysts obtained by supporting bis(n‐butylcyclopentadienyl)zirconium dichloride/methylaluminoxane on: (1) porous crosslinked poly(2‐hydroxyethylmethacrylate‐co‐styrene‐co‐divinylbenzene) particles (CAT1); (2) swellable crosslinked poly(styrene‐co‐divinylbenzene) particles (CAT2); and (3) by evaporating the catalyst precursors solution to dry powder, CAT3 were used in gas‐phase polymerization of ethylene, and ethylene/1‐hexene in a 2 L semi‐batch reactor at 80 °C and 1.4 MPa. The average polymerization activities of the three catalysts were 12.3–15.5, 4.2–10.1, and 14.3–62.9 ton PE (mol Zr h)−1 respectively. CAT1 and CAT3 produced polyethylenes with a polydispersity range of 2.3–2.7, while that of CAT2 was 3.5–6.4. The supported catalysts produced polyolefin particles with bulk density of 0.36–0.43 g ml−1, and essentially no fines. Ethylene/1‐hexene co‐polymerization (7 mol m−3 initial 1‐hexene concentration in the reactor) increased polymerization activities and produced lower‐molar‐mass co‐polymers. At 21 mol m−3 1‐hexene the polymerization activities decreased, but the relative amount of the low‐molar‐mass co‐polymer for CAT2 increased, leading to higher polydispersity. Copyright © 2006 Society of Chemical Industry
Crystal morphology and transcrystallization mechanism of isotactic polypropylene induced by fibres: interface nucleation versus bulk nucleation
Authors: Na Bing , Guo Min , Yang Jinghui , Tan Hong , Zhang Qin , Fu Qiang
Published: March 2006

Using polarized optical microscopy (POM) equipped with a hot stage, morphological investigations of an isotactic polypropylene (iPP) matrix, induced by a homogeneous iPP fibre and heterogeneous pure/modified nylon 6 fibres, were carried out. With respect to transcrystallization related to heterogeneous nucleation on the surface of the fibre, the nucleation mode was found to be different for iPP fibres and nylon 6 fibres. An iPP fibre can serve as a macroscopic linear nucleus, similarly to the shish‐type structure formed in stress‐induced crystallization, to induce kebab‐like growth of lamellae, whereas numerous closely packed spherulites along nylon 6 fibres resulted in macroscopic transverse growth to form a transcrystallite owing to the limitation along the fibre axis. The difference in nature between these two transcrystallites can be further demonstrated by their optical characters related to the lamellar arrangement inside the transcrystallite. As for homogeneous iPP composites, the formation of transcrystallites results from lattice matching, in consideration of the same chemical structure and lattice parameters between fibre and matrix. The incorporation of calcium chloride into a nylon 6 fibre—to destroy its crystal structure—confirmed the role of lattice matching between nylon 6 fibre and iPP matrix. The addition of atactic polypropylene (aPP) in order to enhance the nucleation ability of the iPP matrix also greatly weakened transcrystallization. Our work demonstrates that transcrystallization is just a matter of competition between interface nucleation and bulk nucleation, namely, if interface nucleation is faster than bulk nucleation, transcrystallization will develop. If not, it will be suppressed. Copyright © 2006 Society of Chemical Industry
Synthesis, structure and properties of carbon nanotube/poly(p‐phenylene benzobisoxazole) composite fibres
Authors: Li Jinhuan , Chen Xiangqun , Li Xia , Cao Hailin , Yu Hongyan , Huang Yudong
Published: March 2006

Carbon nanotube/poly(p‐phenylene benzobisoxazole) (CNT/PBO) composite fibres were prepared by in situ polymerization and dry‐jet wet spinning. The structure and properties of the CNT/PBO fibres were investigated. FTIR and viscosity measurements showed that the functional groups on the CNT surface took part in the polymerization and affected the chemical structure and molecular weight of the composite. CNT/PBO composites with high molecular weight could be obtained by controlling the amount and addition time of CNTs. Compared with PBO fibres containing no CNTs prepared under the same conditions, the thermal resistance of the CNT (2 wt%)/PBO fibres was higher and the tensile strength was also improved by 20–50%. WAXD and SEM measurements indicated that the orientation degree of the CNT (2 wt%)/PBO fibres was smaller than that of PBO fibres. The fracture surfaces of these two fibres were also different. CNT dispersion in the CNT (2 wt%)/PBO fibres was examined by TEM. A model of the interactions between CNTs and PBO is proposed, based on these results. Copyright © 2006 Society of Chemical Industry