bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of hydrophobically associated polyacrylamide‐containing aqueous fluids and their potential use in petroleum recovery
Authors: Chagas Beatriz S. , Machado Dilon L. P. , Haag Roberto B. , De Souza Celso R. , Lucas Elizabete F.
Published: January 2004

Acrylamide and tridecyl acrylate copolymers were synthesized by micellar copolymerization to obtain water‐soluble, hydrophobically modified polymers. Rheological properties of the obtained polymer solutions were evaluated and compared to those of solutions of a commercial polyacrylamide currently used in the petroleum industry. The behavior of the copolymer solutions was studied as a function of the variation of hydrophobic monomer content incorporated in the copolymer as well as the salt content of the aqueous medium, for diluted and semi‐diluted regimens. Comparative studies of such effects on the intrinsic viscosity and the critical concentration of those polymers were conducted. The increase in hydrophobic monomer content produced a sudden increase in the bulk and absolute viscosity of the polymeric solutions, a trend that was more intense from a certain concentration typical for each polymer. Salt addition led to lower bulk viscosity caused by a stronger interaction among hydrophobic groups, resulting from minimized exposure of such groups and water. The same effect was observed for the critical concentration. A comparison of the synthesized polymers with industrial polyacrylamide showed that the synthesized polymers were characterized by advantageously high shear strength and high salt resistance. However, in the absence of salts, higher copolymer amounts were needed to prepare solutions whose viscosity was the same as that of commercial polyacrylamide. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3686–3692, 2004
Pervaporation study of water and tert‐butanol mixtures
Authors: Guo Wei Fen , Chung Tai‐Shung , Matsuura Takeshi , Wang Rong , Liu Ye
Published: January 2004

The permeation behavior of water/tert‐butanol mixture through Sulzer Pervap2510 hydrophilic poly(vinyl alcohol) membranes was investigated and the effects of feed composition and temperature on separation efficiency of the membranes were studied. The pervaporation experiments were carried out with feed water content varying from 0 to 20 wt % according to the existing industrial needs and with the feed temperature from 60 to 100°C. Over this range, both water flux and separation factor increased with increasing water content and feed temperature. These phenomena may be attributed to (1) the strong interaction between water and the membrane, (2) the decoupling effect of the permeants and the membrane at elevated temperatures, and (3) the steric hindrance effect of branch chain alcohol. The permeability ratio (the ideal separation factor) of water to tert‐butanol across the membrane was calculated and found to follow the same relationship with increasing temperature and water content. Both flux and separation factor obtained from the Pervap2510 membrane in this study were much higher than previous reported values, possible causes for which were analyzed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4082–4090, 2004
Oxygen microwave plasma treatment of silicone elastomer: Kinetic behavior and surface composition
Authors: Olander Björn , Wirsén Anders , Albertsson Ann‐Christine
Published: January 2004

Silicone elastomers were surface modified by oxygen microwave plasma under different conditions and the elemental composition was followed by X‐ray photoelectron spectroscopy (XPS). The changes in elemental composition were mapped by a method based on ternary XPS diagrams that we have recently developed. Already at the shortest treatment times, 5 s, the change in surface composition is more than one‐half the maximum change obtained on prolonged exposure. After this initial change, the surface gradually oxidizes toward the final composition. Curve resolutions of C1s and Si2p XPS data showed that the initial jump in surface composition is caused by an oxidation of silicon where one of the two methyl groups are replaced by an oxygen. The second methyl group appears to be more difficult to remove, but as the treatment progresses, the number of oxygen bonded to silicon gradually increases. The dominating form of carbon acts as unoxidized methyl groups throughout the process, but the total carbon percentage decreases as the treatment progresses. This indicates either that the methyl groups are removed without prior oxidation or that the methyl groups are removed shortly after oxidation. A silica‐like surface layer was formed on prolonged plasma treatment under all the investigated conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4098–4104, 2004
The effect of mutations altering biogenic amine metabolism in Drosophila on viability and the response to environmental stresses
Authors: Gruntenko N. , Chentsova N.A. , Bogomolova E.V. , Karpova E.K. , Glazko G.V. , Faddeeva N.V. , Monastirioti M. , Rauschenbach I. Yu.
Published: January 2004

Dopamine (DA) content, tyrosine decarboxylase (TDC) activity and survival were studied under normal and environmental stress conditions in the ste and e strains carrying ebony mutation increasing DA level and the octopamineless strain TβhnM18 of Drosophila melanogaster. Wild‐type strains Canton S and Oregon R, and strain p845 from which TβhnM18 strain was derived were used as controls. Sexual dimorphism of TDC activity, DA content, and survival in flies of all D. melanogaster strains under study was found. TβhnM18 mutation sharply reduced TDC activity in females, while ebony had no such effect. DA content and survival under heat stress in TβhnM18 flies did not differ from those in the wild type. ste and e flies had drastically increased DA content under normal conditions, dramatically decreased survival under heat stress, but increased survival under starvation. DA content and survival under heat stress were also studied in the reciprocal hybrids (males) F1 of the cross D. virilis strains 101 (wild type) and 147 with X‐linked mutation, which significantly increases DA content. 147×101 males had a considerably higher DA content and lower survival than 101×147 ones. Individuals of all D. melanogaster strains under study developed the stress reaction, as judged by changes in TDC activity and DA levels. The role of biogenic amines in the stress reaction development and adaptation to environmental stresses in Drosophila is discussed. Arch. Insect Biochem. Physiol. 55:55–67, 2004. © 2004 Wiley‐Liss, Inc.
Morphological and molecular effects of 20‐hydroxyecdysone and its agonist tebufenozide on CF‐203, a midgut‐derived cell line from the spruce budworm, Choristoneura fumiferana
Authors: Hu Wenqi , Cook Barbara J. , Ampasala Dinakara R. , Zheng Sichun , Caputo Guido , Krell Peter J. , Retnakaran Arthur , Arif Basil M. , Feng Qili
Published: January 2004

The morphological and molecular responses of a midgut‐derived cell line of the spruce budworm, Choristoneura fumiferana, to 20‐hydroxyecdysone (20E) and the nonsteroidal ecdysone agonist, tebufenozide (RH‐5992), were investigated. The cells responded to these compounds by clumping, generating filamentous extensions, increased mortality and expression of the transcription factor, Choristoneura hormone receptor 3 (CHR3). This cell line can be used as a model system to study the mode of action of ecdysone and its agonists. With subsequent passaging in ecdysteroid‐containing medium, the degree of clumping increased and the clumping could not be reversed by subculturing in ecdysteroid‐free medium. Cell numbers of the adapted cell lines in 20E and RH‐5992 containing media were not significantly decreased, compared to the control, but both cell lines accumulated less 14C‐labeled RH‐5992 and lost the capability of expressing CHR3 in response to these compounds. Taken together, the cell lines appeared to develop a mechanism to adapt to the toxic effects of these compounds. Arch. Insect Biochem. Physiol. 55:68–78, 2004. © 2004 Wiley‐Liss, Inc.
Role of antioxidant defense during different stages of preadult life cycle in European corn borer (Ostrinia nubilalis, Hubn.): Diapause and metamorphosis
Authors: Jovanović‐Galović A. , Blagojević D.P. , Grubor‐Lajšić G. , Worland R. , Spasić M.B.
Published: January 2004

Antioxidant enzymes, total glutathione (GSH), and ascorbic acid (ASA) were determined in whole body homogenates of nondiapausing larvae, diapausing larvae during the diapausing period (October, December, and February), and in pupae emerged from both diapausing and nondiapausing larvae of the European corn borer (Ostrinia nubilalis, Hubn., Lepidoptera: Pyralidae). The activities of catalase, selenium nondependent glutathione peroxidase (GPx), and glutathione‐S‐transferase (GST), as well as the content of GSH and ASA, were found to vary throughout the larval diapause. Compared to diapausing larvae, nondiapausing larvae were higher in levels of catalase, GPx, GST, and dehydroascorbate reductase (DHAR) activity. GSH content was also increased. However, nondiapausing larvae contained less ASA than diapausing ones. Pupae had higher GPx and GST activity and an increased ASA content compared to larvae. The pupae emerged from nondiapausing larvae had higher GST, glutathione reductase (GR), and DHAR activities, but lower GPx activity and ASA content than those emerged from diapausing larvae. Correlation analysis revealed differences in the way the antioxidant level is equilibrated for a particular stage and developmental pattern. The results suggest that cellular antioxidants are involved in both the protection of cells and the regulation of redox levels during the pre‐adult stages of Ostrinia nubilalis. Arch. Insect Biochem. Physiol. 55:79–89, 2004. © 2004 Wiley‐Liss, Inc.
Changes in leucine transport activity in Chironomus riparius larvae after short‐term exposure to potassium dichromate and fenitrothion
Authors: Forcella Matilde , Berra Elisa , Giacchini Roberto , Hanozet Giorgio M. , Parenti Paolo
Published: January 2004

The effect of sublethal concentrations of potassium dichromate and fenitrothion on sodium‐leucine cotransport in brush border membrane vesicles from Chironomus riparius larvae has been investigated. Exposure to potassium dichromate and fenitrothion caused a dose‐ and time‐dependent inhibition of leucine uptake. Transport inhibition is easily detectable at doses 100‐fold lower than LD50. Kinetic experiments showed that inhibition was mainly caused by a decrease of the Vmax (680 ± 53 vs. 382 ± 23 and 555 ± 27 nmol/15s/mg protein in control and exposed larvae to K2Cr2O7 and fenitrothion, respectively). Inhibition is possibly related to a variation of sodium ions permeability as evidenced by increased membrane lipid peroxidation. Appropriate control experiments ruled out that the observed differences could be due to changes in general features of membrane preparations. Transport inhibition observed in larvae exposed to potassium dichromate was accompanied by changes in ascorbate peroxidase and dehydroascorbate reductase activities, whereas those exposed to fenitrothion displayed an increase in transaminase activity. The possible value of leucine uptake as biochemical biomarker is briefly discussed. Arch. Insect Biochem. Physiol. 55:90–101, 2004. © 2004 Wiley‐Liss, Inc.
Developmental toxicity of arecoline, the major alkaloid in betel nuts, in zebrafish embryos
Authors: Chang Bei‐En , Liao Mei‐Hui , Kuo M. Yen‐Ping , Chen Chi‐Hsiang
Published: January 2004

Background

The major alkaloid in the betel nut, arecoline, has been reported to be potent in inducing developmentally toxic effects by generally lowering the embryo weight and retarding development of the embryo. This study examined the adverse effects of arecoline and tried to unravel the mechanism through the tools of molecular biology.

METHODS

Arecoline was administered to zebrafish embryos by incubation at concentrations ranging from 0.01–0.04% (wt/vol) and lethality and morphological changes were recorded. The expression of genes was analyzed by reverse transcription‐polymerase chain reaction (RT‐PCR) and whole‐mount in situ hybridization. In addition, the protective effects of several antioxidants were tested.

RESULTS

The survival rate of treated embryos during a three‐day incubation significantly declined as the arecoline concentration increased. Treated embryos showed general growth retardation and lower rate of heartbeat. When examined at the 24‐hr stage, the relative amounts of transcripts of p53, p21, and cyclin D1, and the spatial expression patterns of these genes in treated groups, were comparable to those of the untreated early stages of embryos. Finally, the addition of glutathione (GSH) or its precursor, N‐acetyl‐L‐cysteine (NAC), ameliorated the developmental retardation of embryos by arecoline.

CONCLUSIONS

Arecoline‐treated embryos exhibited general developmental retardation in a dose‐dependent manner. Our results from RT‐PCR, in situ hybridization, and antioxidant‐protection experiments indicate that the mechanism underlying growth retardation by arecoline in embryos is predominately due to a general cytotoxic effect induced by depletion of intracellular thiols. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Analyzing protein–protein interactions in cell membranes
Authors: Nohe Anja , Petersen Nils O.
Published: January 2004

Interactions among membrane proteins regulate numerous cellular processes, including cell growth, cell differentiation and apoptosis. We need to understand which proteins interact, where they interact and to which extent they interact. This article describes a set of novel approaches to measure, on the surface of living cells, the number of clusters of proteins, the number of proteins per cluster, the number of clusters or membrane domains that contain pairs of interacting proteins and the fraction of one protein species that interacts with another protein within these domains. These data can then be interpreted in terms of the function of the protein‐protein interactions. BioEssays 26:196–203, 2004. © 2004 Wiley Periodicals, Inc.
A cluster translocation model may explain the collinearity of Hox gene expressions
Authors: Papageorgiou Spyros
Published: January 2004

A model is proposed that deals with the observed collinearities (spatial, temporal and quantitative) of Hox gene expression during pattern formation along the primary and secondary axes of vertebrates. In particular, in the proximodistal axis of the developing limb, it is assumed that a morphogen gradient is laid down with its source at the distal tip of the bud. The extracellular signals in every cell of the morphogenetic field are transduced and uniformly amplified so that molecules are produced in the nucleus with appropriate physicochemical properties. These molecules can exert a concentration‐dependent force on the Hox cluster. It is assumed that, before activation, the Hox cluster is packaged as an elongated rigid body inside the chromatin and is covered by a coat that prevents the transcription factors reaching the genes of the cluster. The transcription factors are confined to the interchromatin domain and their density decreases with their distance from the chromatin surface. A gradual increase in the extracellular morphogen concentration causes a corresponding increase in the number of the nuclear molecules and the resulting bigger force pushes the Hox cluster toward the interchromatin domain. The step‐by‐step translocations of the Hox cluster initiate the consecutive exposure of genes to their transcription factors. The model explains how gene activation is triggered and it describes spatial, temporal and quantitative collinearities at the initial stages of gene expression. Some recent experiments of Hox deletions and duplications are accounted for by the model. BioEssays 26:189–195, 2004. © 2004 Wiley Periodicals, Inc.
The many colours of chromodomains
Authors: Brehm Alexander , Tufteland Katharina R. , Aasland Rein , Becker Peter B.
Published: January 2004

Local differences in chromatin organisation may profoundly affect the activity of eukaryotic genomes. Regulation at the level of DNA packaging requires the targeting of structural proteins and histone‐modifying enzymes to specific sites and their stable or dynamic interaction with the nucleosomal fiber. The “chromodomain”, a domain shared by many regulators of chromatin structure, has long been suspected to serve as a module mediating chromatin interactions in a variety of different protein contexts. However, recent functional analyses of a number of different chromodomains revealed an unexpected diversity of interaction targets, including histones, DNA and even RNA. The chromodomains of today seem to have evolved from a common ancestral fold to fulfill various functions in different molecular contexts. Combining information gained from recent functional and structural studies of chromodomains with a bioinformatic classification of their structure could lead to the definition of sequence motifs with predictive quality for chromodomain function. BioEssays 26:133–140, 2004. © 2004 Wiley Periodicals, Inc.
Sex determination: insights from the chicken
Authors: Smith Craig A. , Sinclair Andrew H.
Published: January 2004

Not all vertebrates share the familiar system of XX:XY sex determination seen in mammals. In the chicken and other birds, sex is determined by a ZZ:ZW sex chromosome system. Gonadal development in the chicken has provided insights into the molecular genetics of vertebrate sex determination and how it has evolved. Such comparative studies show that vertebrate sex‐determining pathways comprise both conserved and divergent elements. The chicken embryo resembles lower vertebrates in that estrogens play a central role in gonadal sex differentiation. However, several genes shown to be critical for mammalian sex determination are also expressed in the chicken, but their expression patterns differ, indicating functional plasticity. While the genetic trigger for sex determination in birds remains unknown, some promising candidate genes have recently emerged. The Z‐linked gene, DMRT1, supports the Z‐dosage model of avian sex determination. Two novel W‐linked genes, ASW and FET1, represent candidate female determinants. BioEssays 26:120–132, 2004. © 2004 Wiley Periodicals, Inc.
The use of animal models in the study of complex disease: all else is never equal or why do so many human studies fail to replicate animal findings?
Authors: Williams Scott M. , Haines Jonathan L. , Moore Jason H.
Published: January 2004

The study of the genetics of complex human disease has met with limited success. Many findings with candidate genes fail to replicate despite seemingly overwhelming physiological data implicating the genes. In contrast, animal model studies of the same genes and disease models usually have more consistent results. We propose that one important reason for this is the ability to control genetic background in animal studies. The fact that controlling genetic background can produce more consistent results suggests that the failure to replicate human findings in the same diseases is due to variation in interacting genes. Hence, the contrasting nature of the findings from the different study designs indicates the importance of non‐additive genetic effects on human disease. We discuss these issues and some methodological approaches that can detect multilocus effects, using hypertension as a model disease. This article contains supplementary material, which may be viewed at the BioEssays website at http://www.interscience.wiley.com/jpages/0265‐9247/suppmat/index.html. BioEssays 26:170–179, 2004. © 2004 Wiley Periodicals, Inc.
The life and death of sponge cells
Authors: Sipkema Detmer , Snijders Ambrosius P. L. , Schroën Carin G. P. H. , Osinga Ronald , Wijffels René H.
Published: January 2004

Cell viability is an essential touchstone in the study of the effect of medium components on cell physiology. We developed a flow‐cytometric assay to determine sponge‐cell viability, based on the combined use of fluorescein diacetate (FDA) and propidium iodide (PI). Cell fluorescence measurements based on incubation of cells with FDA or PI resulted in a useful and reproducible estimate of the viability of primary sponge‐cell cultures. We studied the effects of temperature, ammonium, and the fungicide amphotericin B on the viability of a primary‐cell culture from the marine sponge Suberites domuncula using the aforementioned flow‐cytometric assay. S. domuncula cells die rapidly at a temperature of ≥22°C, but they are insensitive to ammonium concentrations of up to 25 mM. Amphotericin B, which is frequently used in sponge‐cell culture media, was found to be toxic to S. domuncula cells. © 2004 Wiley Periodicals, Inc.
Laboratory evolution of cytochrome P450 BM‐3 monooxygenase for organic cosolvents
Authors: Seng Wong Tuck , Arnold Frances H. , Schwaneberg Ulrich
Published: January 2004

Cytochrome P450 BM‐3 (EC 1.14.14.1) catalyzes the hydroxylation and/or epoxidation of a broad range of substrates, including alkanes, alkenes, alcohols, fatty acids, amides, polyaromatic hydrocarbons, and heterocycles. For many of these notoriously water‐insoluble compounds, P450 BM‐3's Km values are in the millimolar range. Polar organic cosolvents are therefore added to increase substrate solubility and achieve high catalytic efficiency. Using P450 BM‐3 as a catalyst for these important transformations requires that we improve its ability to tolerate the cosolvents. By directed evolution, we improved the activity of P450 BM‐3 in the presence of dimethylsulfoxide (DMSO) and tetrahydrofuran (THF), achieving increases in specific activity up to 10‐fold in 2% (v/v) THF and 6‐fold in 25% (v/v) DMSO. The engineered P450 BM‐3's are also significantly more resistant to acetone, acetonitrile, dimethylformamide, and ethanol as cosolvents in the reaction. © 2004 Wiley Periodicals, Inc.
New tools for mass isotopomer data evaluation in 13C flux analysis: Mass isotope correction, data consistency checking, and precursor relationships
Authors: Wahl S.Aljoscha , Dauner Michael , Wiechert Wolfgang
Published: January 2004

13C metabolic flux analysis (MFA) is based on carbon‐labeling experiments where a specifically 13C labeled substrate is fed. The labeled carbon atoms distribute over the metabolic network and the label enrichment of certain metabolic pools is measured by using different methods. Recently, MS methods have been dramatically improved—large and precise datasets are now available. MS data has to be preprocessed and corrected for natural stable mass isotopes. In this article we present (1) a new elegant method to correct MS measurement data for natural stable mass isotopes by infinite dimensional matrix calculus and (2) we statistically analyze and discuss a reconstruction of labeling pattern in metabolic precursors from biosynthesis molecules. Moreover, we establish a new method for consistency checking of MS spectra that can be applied for automatic error recognition in high‐throughput flux analysis procedures. Preprocessing the measurement data changes their statistical properties which have to be considered in the subsequent parameter fitting process for 13C MFA. We show that correcting for stable mass isotopes leads to rather small correlations. On the other hand, a direct reconstruction of a precursor labeling pattern from an aromatic amino acid measurement turns out to be critical. Reasonable results are only obtained if additional, independent information about the labeling of at least one precursor is available. A versatile MatLab tool for the rapid correction and consistency checking of MS spectra is presented. Practical examples for the described methods are also given.©2004 Wiley Periodicals, Inc.
Acrylamid — und seine Folgen für die Ernährung und den Chemieunterricht
Authors: Zimmermann Heidi , Kreher Richard P. , Schmidkunz Heinz
Published: January 2004

MIT DEM SCHLAGWORT Acrylamid lässt sich der Kontext zur produktgeprägten Lebenswelt einfach herstellen.
Schwieriger ist es, durch Reflektieren und Systematisieren das Verständnis für das strukturelle Konzept und die Reaktivität organischer Verbindungen zu finden und das Ziel zu erreichen, fachliche Kompetenz zu vermitteln sowie Erfahrungs‐ und Handlungsfähigkeit zu entwickeln. Die Anregung zu dieser Übersicht geht auf einen aktuellen Beitrag von W. Hardam [1] zurück.

In elementarisierter Form werden zunächst fachliche Probleme und gesundheitliche Gefährdungen beschrieben sowie konkrete Bezüge zu den fachlichen Grundlagen (Namen‐ und Redox‐Reaktionen) aufgezeigt. Im letzten Abschnitt werden didaktische Zusammenhänge mit elementaren Lernstandards aufgezeigt und in einem Internet‐Anhang (Anlagen I‐V) die Perspektiven mit dem aktuellen Stand der Forschung vermittelt.

http://www.uni‐dortmund.de
Chemie der Wunderkerze — ein Thema nicht nur in der Weihnachtszeit
Authors: Martin Christina , de Vries Tönjes
Published: January 2004

DAS VERSTÄNDNIS von Redox‐Reaktionen gehört zu den wesentlichen Inhalten des Chemieunterrichts. Dabei wird in der Regel zunächst die Reaktion von Metallen mit verschiedenen Metalloxiden betrachtet, um daraus als strukturierendes Prinzip die Redox‐Reihe der Metalle zu entwickeln. Im weiteren Verlauf werden dann auch Nichtmetalle bzw. Nichtmetalloxide wie z.B. Wasser oder Kohlenstoffdioxid in diese Reihe integriert.

Im folgenden Beitrag möchten wir eine Unterrichtskonzeption vorstellen, in der Wunderkerzen als motivierender Ausgangspunkt für die vertiefende Betrachtung von Redox‐Reaktionen dienen. Es wird gezeigt, dass Wunderkerzen, vielfach entgegen den Erwartungen der Schüler, auch in sauerstofffreier Atmosphäre brennen. Man kann aus ihnen sogar eine „Fackel”︁ bauen, die unter Wasser weiter brennt. Darüber hinaus lassen sich beim herkömmlichen Abbrennen von Wunderkerzen an der Luft im Schülerexperiment zahlreiche Reaktionsprodukte nachweisen, u.a. auch emittierte nitrose Gase. In diesem Zusammenhang wird über potenzielle Gesundheitsgefahren aufgeklärt und auch experimentell gezeigt, dass das Abbrennen von Wunderkerzen auf Kuchen nicht unbedingt ein „Leckerbissen”︁ ist. In einigen Klassen der Oberstufe ist diese Konzeption bereits praktisch erprobt worden, so dass Schüleräußerungen in diesem Beitrag aufgegriffen werden.
Alkaloide — ein Unterrichtsthema mit historischen, chemischen und präventiven Bezügen
Authors: Yilmaz Ayhan , Uludağ Nesimi , Morgil Fatma Inci
Published: January 2004

DAS ZIEL DER VORLIEGENDEN ARBEIT ist es, die chemischen Eigenschaften von Alkaloiden wie Nikotin, Morphin, Kokain sowie Koffein und die Beeinträchtigung der Gesundheit durch den Konsum dieser Stoffe darzustellen. Es ist bekannt, dass diese Alkaloide eine große Bedeutung in der Gesellschaft haben, da sie legal oder auch illegal konsumiert und dass sie meist als Substanzen verstanden werden, die den Menschen in eine heitere Stimmung bzw. in einen Rausch versetzen. Es ist daher von enormer Bedeutung, dass die Schüler und die Erwachsenen unterschiedlichen Bildungsgrades in dieser Hinsicht aufgeklärt bzw. unterrichtet werden. Wir haben diskutiert, wie dieses Thema im Unterricht der Sekundarstufe in unserem Heimatland behandelt werden kann. Ferner haben wir diesbezüglich Unterrichtsbücher untersucht und Schulexperimente für die Schüler vorgeschlagen. Weiterhin wurden Zahlen von Abhängigen aus der Türkei, Europa und Amerika verglichen, die der Alkaloide konsumieren. Daraus geht hervor, dass die Zahlen in den letzten Jahren gefährlich angestiegen sind.
Radiofrequency ablation
Authors: Tanabe Kenneth K. , Curley Steven A. , Dodd Gerald D. , Siperstein Allan E. , Goldberg S. Nahum
Published: January 2004

Dr. Kenneth K. Tanabe solicited opinions from two interventional radiologists and two surgeons who have made groundbreaking innovations in the field of radiofrequency ablation. He asked each to address four questions, and the responses succinctly describe the current state and the future of radiofrequency ablation.
Breast magnetic resonance image screening and ductal lavage in women at high genetic risk for breast carcinoma
Authors: Hartman Anne‐Renee , Daniel Bruce L. , Kurian Allison W. , Mills Meredith A. , Nowels Kent W. , Dirbas Frederick M. , Kingham Kerry E. , Chun Nicki M. , Herfkens Robert J. , Ford James M. , Plevritis Sylvia K.
Published: January 2004

BACKGROUND

Intensive screening is an alternative to prophylactic mastectomy in women at high risk for developing breast carcinoma. The current article reports preliminary results from a screening protocol using high‐quality magnetic resonance imaging (MRI), ductal lavage (DL), clinical breast examination, and mammography to identify early malignancy and high‐risk lesions in women at increased genetic risk of breast carcinoma.

METHODS

Women with inherited BRCA1 or BRCA2 mutations or women with a > 10% risk of developing breast carcinoma at 10 years, as estimated by the Claus model, were eligible. Patients were accrued from September 2001 to May 2003. Enrolled patients underwent biannual clinical breast examinations and annual mammography, breast MRI, and DL.

RESULTS

Forty‐one women underwent an initial screen. Fifteen of 41 enrolled women (36.6%) either had undergone previous bilateral oophorectomy and/or were on tamoxifen at the time of the initial screen. One patient who was a BRCA1 carrier had high‐grade ductal carcinoma in situ (DCIS) that was screen detected by MRI but that was missed on mammography. High‐risk lesions that were screen detected by MRI in three women included radial scars and atypical lobular hyperplasia. DL detected seven women with cellular atypia, including one woman who had a normal MRI and mammogram.

CONCLUSIONS

Breast MRI identified high‐grade DCIS and high‐risk lesions that were missed by mammography. DL detected cytologic atypia in a high‐risk cohort. A larger screening trial is needed to determine which subgroups of high‐risk women will benefit and whether the identification of malignant and high‐risk lesions at an early stage will impact breast carcinoma incidence and mortality. Cancer 2004. © 2004 American Cancer Society.
The relationship of increasing radiotherapy dose to reduced distant metastases and mortality in men with prostate cancer
Authors: Jacob Rojymon , Hanlon Alexandra L. , Horwitz Eric M. , Movsas Benjamin , Uzzo Robert G. , Pollack Alan
Published: January 2004

BACKGROUND

The association of increasing radiotherapy (RT) dose with reduced biochemical failure (BF) is accepted widely. However, there is little direct evidence that dose escalation has an impact on distant metastasis (DM) or overall mortality (OM). These associations were examined in the current study.

METHODS

The outcome of 835 patients who were treated at the Fox Chase Cancer Center (Philadelphia, PA) between 1989 and 1997 using 3‐dimensional, conformal RT alone (median dose, 74 Gray [Gy]) was analyzed. Stepwise multivariate Cox proportional hazards regression analyses (MVAs) were performed with RT dose included as a covariate along with log‐transformed initial pretreatment PSA level, Gleason score, palpation T status, age, and year of treatment (YOT), where indicated. To minimize the effect of YOT, an analysis was performed on a subgroup of 363 patients who were treated prior to 1994.

RESULTS

With a median follow‐up of 64 months, there were 220 PSA failures, 44 distant metastases, and 162 deaths. In MVA, RT dose (as a continuous variable) was a significant predictor for BF, DM, and OM. When YOT was included as a covariate, it was related strongly to all endpoints, and the correlations of RT dose with DM and OM were lost. When the effect of YOT was minimized by limiting the MVA to patients who were treated prior to 1994, RT dose again emerged as a significant predictor of DM.

CONCLUSIONS

Escalation of RT dose reduced the rates of BF, DM, and OM significantly in patients with prostate cancer. The inclusion of YOT had a pronounced effect on these correlations that may confound interpretation. Cancer 2004. © 2003 American Cancer Society.
Effects of pregnancy after treatment for breast carcinoma on survival and risk of recurrence
Authors: Blakely L. Johnetta , Buzdar Aman U. , Lozada Jose A. , Shullaih Samer A. , Hoy Emma , Smith Terry L. , Hortobagyi Gabriel N.
Published: January 2004

BACKGROUND

The goal of the current study was to assess the effect of pregnancy on the subsequent risk of recurrence after treatment for breast carcinoma, adjusting for established prognostic factors.

METHODS

Between 1974 and 1998, 383 patients age ≤ 35 years were treated for breast carcinoma with adjuvant chemotherapy at The University of Texas M. D. Anderson Cancer Center (Houston, TX). The median follow‐up period was 13 years. Of these, 13 patients were excluded from analysis, as no history was available regarding pregnancy; 240 (65%) were > 30 years old; 47 (13%) had at least 1 pregnancy after therapy; 32 had full‐ term pregnancies; 10 had spontaneous or elective abortions; 4 had miscarriages; and 1 had a premature delivery. Estrogen receptor (ER) status, lymph node involvement, and disease stage were evaluated as potential risk factors for recurrence. Information on ER status was unavailable for 123 (33%) patients.

RESULTS

Patients who experienced a pregnancy tended to have earlier‐stage disease (Stage I/II: 80% vs. 73%), fewer positive lymph nodes (< 4: 87% vs. 52%), more ER negativity (68% vs. 58%), and younger age (< 30 years: 57% vs. 32%) than patients who did not. The incidence of disease recurrence was 23% for women who experienced a pregnancy and 54% for women who did not. The hazard ratio (using the multivariate Cox proportional hazards model) for disease recurrence in patients with posttreatment pregnancy was 0.71 (P = 0.4).

CONCLUSIONS

In the current study population, pregnancy was not associated with an increased risk of disease recurrence or poorer survival in patients previously treated for breast carcinoma. Cancer 2004. © 2003 American Cancer Society.
Prognostic significance of intratumoral lymphangiogenesis in squamous cell carcinoma of the oral cavity
Authors: Muñoz‐Guerra Mario Fernando , Marazuela Eva G. , Martín‐Villar Esther , Quintanilla Miguel , Gamallo Carlos
Published: January 2004

BACKGROUND

Clinicopathologic data demonstrated that the lymphatic system is the main route for solid tumor metastasis. However, the effect of intratumoral lymphangiogenesis (IL) on prognosis in oral carcinoma is still unknown because, until recently, no reliable markers for lymphatic endothelium were available. The current study analyzed the lymphatic vessels in tumor tissue specimens of patients with primary oral carcinoma using the new marker, PA2.26.

METHODS

The authors investigated IL in surgical tissue samples of 61 patients with early‐stage (Stages I–II) oral carcinoma. The tissue specimens were stained for PA2.26 and the correlation between IL and relevant parameters was analyzed by the Pearson chi‐square test. In a univariate analysis using the Kaplan–Meier method, IL was analyzed against survival and disease‐free period. Statistical significance of differences between distributions was studied by the log‐rank test. Clinicopathologic parameters, including IL, were entered in a multivariate analysis to determine independent prognostic significance.

RESULTS

Thirty‐three patients had IL. In the follow‐up, a strong association was found between IL and locoregional recurrence (30.3 % of the patients with IL and 7.1% of the patients without IL). The presence of IL did not correlate significantly with the pT classification, primary location, or tumor differentiation. IL was found to have no influence on overall survival in univariate analysis, but there was significant association between IL and disease‐free survival (P = 0.03). Multivariate analysis revealed IL to be the sole independent factor influencing disease‐free interval (P = 0.02).

CONCLUSIONS

These results suggested that IL is associated with locoregional disease recurrence in early‐stage oral carcinoma. The presence of IL was a useful discriminator in predicting the outcome of patients with absence of lymph node metastasis. Cancer 2004. © 2003 American Cancer Society.
High‐dose tamoxifen and sulindac as first‐line treatment for desmoid tumors
Authors: Hansmann Anika , Adolph Claudia , Vogel Tilmann , Unger Andreas , Moeslein Gabriela
Published: January 2004

BACKGROUND

Desmoid tumors are mesenchymal nonmetastasizing neoplasms. Although rare in the general population, they are a common extracolonic manifestation of familial adenomatous polyposis (FAP). Because of high tumor recurrence rates, surgery has been less than satisfactory in the treatment of desmoid tumors. In the current study, high doses of tamoxifen in combination with sulindac were used to treat severe desmoid tumors to avoid surgery.

METHODS

Since 1992, 25 patients at Heinrich Heine University (Dusseldorf, Germany) were treated with a combination of tamoxifen and sulindac. In the current study, 17 patients with FAP‐associated and 8 patients with sporadic desmoid tumors received 120 mg of tamoxifen and 300 mg of sulindac daily. Every 6 months, the protracted course of desmoid growth was measured by computed tomography and/or magnetic resonance imaging scans. Tumor responses were characterized as progressive disease, stable disease (SD), partial regression (PR), and complete regression (CR).

RESULTS

Of the group of patients who received tamoxifen and sulindac as a primary treatment, all three patients with sporadic desmoid tumors demonstrated cessation of growth, and 10 of the 13 patients with FAP‐associated tumors achieved either a PR or CR. In the sporadic desmoid tumor group, eight of nine patients developed tumor recurrences after undergoingsurgery at other institutions. Of these, two patients had SD and two patients had a PR to CR.

CONCLUSIONS

The patients with desmoid tumors who were managed conservatively with high‐dose tamoxifen and sulindac had the best outcome. Desmoid tumor recurrence after surgery was high and in the FAP‐associated tumor group, therapy with tamoxifen and sulindac was found to be less successful. Based on this experience, the authors recommended high‐dose tamoxifen and sulindac as the primary treatment for patients with FAP‐associated desmoid tumors. However, to our knowledge, the best approach after surgical intervention for patients with sporadic desmoid tumors remains to be determined. Cancer 2004. © 2003 American Cancer Society.
Potential applicability of balloon catheter–based accelerated partial breast irradiation after conservative surgery for breast carcinoma
Authors: Pawlik Timothy M. , Perry Allison , Strom Eric A. , Babiera Gildy V. , Buchholz Thomas A. , Singletary Eva , Perkins George H. , Ross Merrick I. , Schecter Naomi R. , Meric‐Bernstam Funda , Ames Frederick C. , Hunt Kelly K. , Kuerer Henry M.
Published: January 2004

BACKGROUND

Balloon catheter–based accelerated partial breast irradiation (APBI) is an alternative to whole‐breast external‐beam irradiation during breast‐conserving therapy (BCT) for breast carcinoma, but it is limited by the size of the segmental mastectomy cavity. There are scant data on the average or optimal volume of resection (VR) in BCT. The objective of the current study was to evaluate the percentage of patients who would be eligible for balloon catheter–based APBI based on the selection criteria of the American Society of Breast Surgeons and the surgical VR.

METHODS

The authors reviewed the medical records of 443 patients with ductal carcinoma in situ (DCIS) or invasive carcinoma treated with BCT. Patient treatment and pathologic data were analyzed to assess VR and eligibility for APBI.

RESULTS

BCT was performed for 178 patients with DCIS and 267 patients with invasive breast carcinoma. The majority of invasive carcinomas (63.3%) were infiltrating ductal carcinomas. The median overall lumpectomy volume was 67.61 cm3, with no significant difference between DCIS and invasive carcinoma (P > 0.05). Although the majority (62.9–82.0%) of patients met the individual selection criteria for APBI, only 27.4% of the cohort was found to be eligible for any type of APBI when the selection criteria were considered together. Based on VR, only approximately one‐half of the patients initially eligible for APBI would be candidates for immediate balloon catheter–based APBI using the 70 cm3 balloon device (13.3%). However, with the new, larger 125 cm3 balloon device, approximately three‐fourths of patients initially eligible for APBI would be eligible for balloon catheter–based APBI at the time of the initial surgical procedure (20.7%). Although not evaluated in the current study, shrinkage of the lumpectomy cavity with time may increase the number of patients eligible based strictly on VR criteria. Patients with a very large VR (≥ 125 cm3) were more likely to have invasive carcinoma (P = 0.02; hazard ratio [HR], 7.4) and tumors ≥ 5 cm on final pathology (P < 0.01; HR, 22.0).

CONCLUSIONS

Approximately one‐fifth to one‐fourth of patients presenting for BCT may be eligible for balloon catheter–based APBI according to accepted national guidelines and VR. VR must be considered when selecting patients for balloon catheter–based APBI, because a minority of patients will have a lumpectomy cavity that exceeds the size limit of the current balloon device. Cancer 2004. © 2003 American Cancer Society.
Prophylactic hepatic arterial infusion chemotherapy for the prevention of liver metastasis in patients with colon carcinoma
Authors: Sadahiro Sotaro , Suzuki Toshiyuki , Ishikawa Kenji , Yasuda Seiei , Tajima Tomoo , Makuuchi Hiroyasu , Saitoh Takuro , Murayama Chieko
Published: January 2004

BACKGROUND

The liver is the most frequent site of recurrence after curative resection in patients with colon carcinoma. For liver metastasis, a high response rate can be achieved with hepatic arterial infusion (HAI) chemotherapy. In the current study, the authors administered 5‐fluorouracil (5‐FU) as adjuvant chemotherapy by HAI to patients with colon carcinoma without liver metastases and studied its effects on recurrence in the liver and survival.

METHODS

A total of 316 patients with preoperative Stage II or Stage III colon carcinoma (according to the 1997 revision of the International Union Against Cancer TNM staging system) were randomly assigned to receive surgery plus 3‐week continuous HAI of 5‐FU or surgery alone. There were 305 eligible patients, of whom the 119 patients assigned to the HAI arm actually received 5‐FU. The primary endpoint was disease‐free survival, whereas the secondary endpoints were overall survival and liver metastasis‐free survival. Analysis was by intent to treat.

RESULTS

There were no significant differences noted in morbidity between the two treatment arms. During the follow‐up period (median, 59.0 months), the incidence of liver metastasis was significantly decreased in the HAI arm whereas there were no significant differences reported between the 2 arms with regard to the frequency of metastasis at other sites. In the HAI arm, the risk ratio for recurrence was 0.40 (95% confidence interval [95% CI], 0.24–0.64; P = 0.0002), the risk ratio for death was 0.37 (95% CI, 0.21–0.67; P = 0.0009), and the risk ratio for liver metastasis was 0.38 (95% CI, 0.22–0.66; P = 0.0005). These differences were found to be significant only for patients with Stage III disease. Toxicities were mild.

CONCLUSIONS

A schedule of 3‐week HAI of 5‐FU given as adjuvant chemotherapy to patients with Stage III colon carcinoma appeared to contribute to a significant decrease in the frequency of liver metastases and was associated with an improved survival rate. Cancer 2004. © 2003 American Cancer Society.
Desmoplastic and neurotropic melanoma
Authors: Su Lyndon D. , Fullen Douglas R. , Lowe Lori , Wang Timothy S. , Schwartz Jennifer L. , Cimmino Vincent M. , Sondak Vernon K. , Johnson Timothy M.
Published: January 2004

BACKGROUND

Desmoplastic and neurotropic melanoma (DNMM) occasionally metastasizes to regional lymph nodes and extranodal sites. The value of sentinel lymph node biopsy (SLNB) has not been demonstrated clearly for patients with DNMM. The authors report on the utility of SLNB in the management of patients with DNMM.

METHODS

The authors identified 33 patients with DNMM who were seen during a 5‐year period in their institution who underwent lymphatic mapping and SLNB. Clinical and histopathologic data were reviewed.

RESULTS

Thirty‐three patients with DNMM underwent SLNB (mean Breslow depth, 4.0 mm; median, 2.8 mm). There were 25 male patients and 8 female patients with a median age of 61 years (range, 31–86 years). Fifty‐two percent of tumors presented in the head and neck region, and 24% were associated with lentigo maligna. Four of 33 patients (12%) without clinical evidence of metastatic disease who underwent SLNB had at least 1 positive sentinel lymph node. No additional positive lymph nodes were found in subsequent therapeutic regional lymphadenectomy in any of these four patients.

CONCLUSIONS

SLNB detected subclinical metastases of DNMM to regional lymph nodes. SLNB at the time of resection can provide useful information to guide early treatment and, coupled with lymphadenectomy in positive patients, may limit tumor spread and prevent recurrence at the draining lymph node basin. Cancer 2004. © 2003 American Cancer Society.
The cancer screening practices of adult survivors of childhood cancer
Authors: Yeazel Mark W. , Oeffinger Kevin C. , Gurney James G. , Mertens Ann C. , Hudson Melissa M. , Emmons Karen M. , Chen Hegang , Robison Leslie L.
Published: January 2004

BACKGROUND

The current study characterized the self‐reported cancer screening practices of adult survivors of childhood cancer.

METHODS

A cohort of 9434 long‐term survivors of childhood cancer and a comparison group of 2667 siblings completed a 289‐item survey that included items regarding cancer‐screening practices.

RESULTS

Overall, 27.3% of female respondents reported performing breast self‐examination (BSE) regularly, 78.2% reported undergoing a Papanicolaou smear within the previous 3 years, 62.4% underwent a clinical breast examination (CBE) within the last year, and 20.9% had gotten a mammogram at least once in their lifetime. Approximately 17.4% of male respondents reported performing regular testicular self‐examination (TSE). Women age ≥ 30 years who had been exposed to chest or mantle radiation therapy were more likely to report undergoing CBE (odds ratio [OR], 1.59; 95% confidence interval [95% CI], 1.32–1.92) and mammography (OR, 1.92; 95% CI, 1.47–2.56). Compared with the sibling comparison group, survivors demonstrated an increased likelihood of performing TSE (OR, 1.52; 95% CI, 1.22–1.85) or BSE (OR, 1.30; 95% CI, 1.10–1.52), of having undergone a CBE within the last year (OR, 1.18; 95% CI, 1.02–1.35), and of ever having undergone a mammogram (OR, 1.82; 95% CI, 1.52–2.17).

CONCLUSIONS

The results of the current study demonstrate that the cancer screening practices among survivors of childhood cancer are below optimal levels. Primary care physicians who include childhood cancer survivors among their patients could benefit these individuals by informing them about future cancer risks and recommending appropriate evidence‐based screening. Cancer 2004. © 2003 American Cancer Society.
Inverse estimation of material properties for sheet metals
Authors: Zhao K. M. , Lee J. K.
Published: January 2004

The main objective of this paper is to estimate the material properties for sheet metals subjected to loading and reverse loading by using an inverse method. Cyclic three‐point bending tests are conducted. Bending moments are computed from the measured data, namely, punch stroke, punch load, bending strain and bending angle. Bending moments are also calculated based on the selected constitutive model. Normal anisotropy and non‐linear isotropic/kinematic hardening are considered. Material parameters are estimated by minimizing the difference between these two bending moments. Modified Levenberg–Marquardt method is used in the optimization procedure. Stress–strain curves are generated with the material parameters found in this way. Copyright © 2004 John Wiley & Sons, Ltd.