bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative anatomy, homologies and evolution of the pectoral and forelimb musculature of tetrapods with special attention to extant limbed amphibians and reptiles
Authors: Abdala Virginia , Diogo Rui
Published: August 2010

The main aim of the present work is to synthesize the information obtained from our dissections of the pectoral and forelimb muscles of representative members of the major extant taxa of limbed amphibians and reptiles and from our review of the literature, in order to provide an account of the comparative anatomy, homologies and evolution of these muscles in the Tetrapoda. The pectoral and forelimb musculature of all these major taxa conform to a general pattern that seems to have been acquired very early in the evolutionary history of tetrapods. Although some muscles are missing in certain taxa, and a clear departure from this general pattern is obviously present in derived groups such as birds, the same overall configuration is easily distinguishable in these taxa. Among the most notable anatomical differences between the groups, one that seems to have relevant evolutionary and functional implications, concerns the distal insertion points of the forearm musculature. In tetrapods, the muscles of the radial and ulnar complexes of the forearm are pleisomorphically mainly inserted onto the radius/ulna or onto the more proximal carpal bones, but in mammals some of these muscles insert more distally onto bones such as the metacarpals. Interestingly, a similar trend towards a more distal insertion of these muscles is also found in some non‐mammalian tetrapod taxa, such as some anurans (e.g. Phyllomedusa). This may be correlated with the acquisition of more subtle digital movement abilities in these latter taxa.
NK‐3 receptor antagonism prevents behavioral sensitization to cocaine: a role of glycogen synthase kinase‐3 in the nucleus accumbens
Authors: Nwaneshiudu Chinwe A. , Unterwald Ellen M.
Published: August 2010

J. Neurochem.(2010)115, 635–642.

Repeated administration of cocaine induces heightened behavioral hyperactivity termed sensitization. Although NK‐3 receptors have been shown to modulate acute cocaine‐induced behaviors, their role in behavioral sensitization is unknown. The present study investigated whether NK‐3 receptor blockade altered behavioral sensitization to cocaine. Additionally, glycogen synthase kinase‐3 (GSK3) has been shown to be involved in dopamine receptor signaling and in development of sensitization; therefore regulation of GSK3 activity in the nucleus accumbens was also investigated. Administration of the NK‐3 receptor antagonist SB 222200 (5 mg/kg, s.c.) prior to repeated cocaine (20 mg/kg, i.p.) prevented the development of sensitized responses after a cocaine challenge. Pre‐treatment with SB 222200 before a cocaine challenge also blocked expression of sensitization. Decrease in GSK3 activity demonstrated by increased phosphorylation of GSK3α and GSK3β was detected 20 mins after an acute cocaine injection. In contrast, a cocaine challenge failed to alter phosphorylation of GSK3α and GSK3β in sensitized mice. SB 222200 prior to repeated cocaine resulted in increased phosphorylation of GSK3α and GSK3β akin to changes following acute cocaine. Collectively, these findings demonstrate the involvement of NK‐3 receptors in development and expression of behavioral sensitization and in regulation of GSK3 activity in the nucleus accumbens after repeated cocaine.
Effect of Sowing Season, Plant Cover, and Climatic Variability on Seedling Emergence and Survival in Burned Austrocedrus chilensis Forests
Authors: Urretavizcaya María F. , Defossé Guillermo E. , Gonda Héctor E.
Published: August 2010

Fire is the most important disturbance factor in Cypress (Austrocedrus chilensis) forests in Patagonia, Argentina. This ecosystem recovers poorly after fire, and direct sowing could be a potentially useful restoration practice. To evaluate the effect of season of sowing, post‐fire plant cover (PC), and climatic variability on seedling emergence and survival, three direct sowing studies were established in two burned cypress stands: Trevelin (xeric conditions) and El Bolsón (mesic conditions). Two studies were conducted in winter (2000 and 2001) and one in spring (2001). Precipitation was higher than the mean during the 2000–2001 growing season and lower during 2001–2002. At both sites, emergence and survival were much higher for winter‐ than for spring‐sown seedlings. In the xeric stand, emergence and survival of winter‐sown seedlings increased with medium and high PC values, after the humid and dry summers, respectively. However, most spring‐sown seedlings did not emerge, and those that did were short‐lived. Because of the more favorable growing conditions in the mesic stand, PC had no effect on emergence and only favored first year survival of winter‐sown seedlings after the dry summer. Spring‐sown seedlings showed no association with PC in the mesic site, probably because the first summer was exceptionally humid. We speculate that shading plants exert a positive effect on cypress seedling establishment, likely by reducing the stress from high temperatures and low water availability. Sowing of small patches under the protection of understory vegetation could be useful in restoring burned cypress stands.
Molecular insight into human platelet antigens: structural and evolutionary conservation analyses offer new perspective to immunogenic disorders
Authors: Landau Meytal , Rosenberg Nurit
Published: August 2010

BACKGROUND: Human platelet antigens (HPAs) are polymorphisms in platelet membrane glycoproteins (GPs) that can stimulate production of alloantibodies once exposed to foreign platelets (PLTs) with different HPAs. These antibodies can cause neonatal alloimmune thrombocytopenia, posttransfusion purpura, and PLT transfusion refractoriness. Most HPAs are localized on the main PLT receptors: 1) integrin αIIbβ3, known as the fibrinogen receptor; 2) the GPIb‐IX‐V complex that functions as the receptor for von Willebrand factor; and 3) integrin α2β1, which functions as the collagen receptor.

STUDY DESIGN AND METHODS: We analyzed the structural location and the evolutionary conservation of the residues associated with the HPAs to characterize the features that induce immunologic responses but do not cause inherited diseases.

RESULTS: We found that all HPAs reside in positions located on the protein surface, apart from the ligand‐binding site, and are evolutionary variable.

CONCLUSION: Disease‐causing mutations often reside in highly conserved and buried positions. In contrast, the HPAs affect residues on the protein surface that were not conserved throughout evolution; this explains their naive effect on the protein function. Nonetheless, the HPAs involve substitutions of solvent‐exposed positions that lead to altered interfaces on the surface of the protein and might present epitopes foreign to the immune system.
Iron deficiency in blood donors: analysis of enrollment data from the REDS‐II Donor Iron Status Evaluation (RISE) study
Authors: Cable Ritchard G. , Glynn Simone A. , Kiss Joseph E. , Mast Alan E. , Steele Whitney R. , Murphy Edward L. , Wright David J. , Sacher Ronald A. , Gottschall Jerry L. , Vij Vibha , Simon Toby L. ,   for the NHLBI Retrovirus Epidemiology Donor Study‐II (REDS‐II)
Published: August 2010

BACKGROUND: Regular blood donors are at risk of iron deficiency, but characteristics that predispose to this condition are poorly defined.

STUDY DESIGN AND METHODS: A total of 2425 red blood cell donors, either first‐time (FT) or reactivated donors (no donations for 2 years) or frequent donors, were recruited for follow‐up. At enrollment, ferritin, soluble transferrin receptor (sTfR), and hemoglobin were determined. Donor variables included demographics, smoking, dietary intake, use of iron supplements, and menstrual and/or pregnancy history. Models to predict two measures of iron deficiency were developed: Absent iron stores (AIS) were indicated by a ferritin level of less than 12 ng/mL and iron‐deficient erythropoiesis (IDE) by a log(sTfR/ferritin) value of 2.07 or greater.

RESULTS: A total of 15.0% of donors had AIS and 41.7% IDE. In frequent donors, 16.4 and 48.7% of males had AIS and IDE, respectively, with corresponding proportions of 27.1 and 66.1% for females. Donation intensity was most closely associated with AIS and/or IDE (odds ratios from 5.3 to 52.2 for different donation intensity compared to FT donors). Being female, younger, and/or menstruating also increased the likelihood of having AIS and/or IDE, as did having a lower weight. Marginally significant variables for AIS and/or IDE were being a nonsmoker, previous pregnancy, and not taking iron supplements. Dietary variables were in general unrelated to AIS and/or IDE, as was race and/or ethnicity.

CONCLUSION: A large proportion of both female and male frequent blood donors have iron depletion. Donation intensity, sex and/or menstrual status, weight, and age are important independent predictors of AIS and/or IDE. Reducing the frequency of blood donation is likely to reduce the prevalence of iron deficiency among blood donors, as might implementing routine iron supplementation.
Risk Uncertainty and Supply Chain Decisions: A Real Options Perspective
Authors: Hult G. Tomas M. , Craighead Christopher W. , Ketchen, Jr. David J.
Published: August 2010

Supply chain risk uncertainty can create severe repercussions, thus it is not surprising that research interest in supply chain risk has been growing. While extant inquiry is informative, there is a lack of investigations that center on supply chain investment decisions when facing high levels of risk uncertainty. Given the potential dollar value involved in these decisions, an understanding of how these supply chain decisions are made is of significant theoretical and practical importance. Real options theory, with its focus on decision making under conditions of uncertainty, is an appealing theoretical lens for this endeavor. In essence, real options theory asserts that managerial decisions center on creating and then exercising or not exercising certain opportunities. To date, theorizing about and investigations of real options have used firms as their focus. Not yet examined are real options within supply chains that cross firm boundaries and drive much of the competitive activity in the modern economy. Accordingly, we extend real options theory to the supply chain context by examining how different types of options are approached relative to supply chain project investments. Specifically, we theorize how the options will be related to perceived value under conditions of high supply chain risk uncertainty. Overall, our investigation builds knowledge by extending real options theory to the supply chain context and by providing evidence suggesting some options operate differently in supply chains than they do in firms.
Multilevel Social Dynamics Considerations for Project Management Decision Makers: Antecedents and Implications of Group Member Tie Development
Authors: Bendoly Elliot , Thomas Dominic , Capra Monica
Published: August 2010

Successful projects represent the effective culmination of management skills, planning, and individual project member strengths. In operations management, such strengths are often viewed predominantly from the perspective of skill base. However, it has become increasingly evident that behavioral traits associated with individuals play a very significant, if not ultimately dominating, role in the effectiveness of certain group projects. Our aim in this study is to look into how certain individual attributes viewed as relevant to these project contexts may lead to social networking decisions that have impacts spanning multiple levels of analysis. Such insights are likely to prove valuable to decision makers managing project teams as well. We employ a controlled 4‐month investigation of multiple projects, for which we are able to consider both objective, and subjective pre‐, in situ, and postproject data. Our results demonstrate that the issues of perceived control, confidence, and conscientiousness are relevant not only in driving individual perceptions of the value of within‐group interactions, and hence the development of associated ties, but are also ultimately relevant in helping to drive higher levels of group performance.
Flexibility or Cost Saving? Sourcing Decisions with Two Suppliers
Authors: Chung Wenming , Talluri Srinivas , Narasimhan Ram
Published: August 2010

This article studies a decentralized supply chain in which there are two suppliers and a single buyer. One supplier offers the quantity flexibility (QF) contract to the buyer, while the other offers the cheaper price. Under the QF contract, the buyer does not assume full responsibility for the forecast, yet the supplier guarantees the availability of the forecasted quantity with additional buffer inventory. On the other hand, the price‐only contract places full inventory burden on the buyer, but with a cheaper price. We study this problem from the buyer's perspective and solve for the buyer's optimal procurement and forecasting decisions. We identify areas where flexibility and cheaper price have an advantage, one over the other. Our results indicate that the buyer significantly benefits from having multiple sources of supply. We also find that, from the system's standpoint, a multisupplier system may outperform a single‐supplier supply chain under certain conditions. Interestingly, we observe that providing too much flexibility may benefit the low‐price supplier rather than benefiting the QF supplier. We discuss the managerial implications and provide directions for future research opportunities.
Remifentanil–Midazolam Sedation Provides Hemodynamic Stability and Comfort During Epicardial Ablation of Ventricular Tachycardia
Authors: MANDEL JEFF E. , HUTCHINSON MATHEW D. , MARCHLINSKI FRANCIS E.
Published: August 2010

Remifentanil for Epicardial VT Ablation. Epicardial ablation of ventricular tachycardia (VT) presents multiple challenges for anesthetic management. General anesthesia lowers blood pressure, may interfere with arrhythmia mapping, and use of muscle relaxants precludes identification of the phrenic nerve. We describe a case in which remifentanil with minimal doses of midazolam was employed in a series of epicardial VT ablations and noninvasive programmed stimulations (NIPS), including 5 external cardioversions and discuss the advantages of this approach. (J Cardiovasc Electrophysiol, Vol. 22, pp. 464‐466)
Protective effects of platinum nanoparticles against UV‐light‐induced epidermal inflammation
Authors: Yoshihisa Yoko , Honda Ayumi , Zhao Qing‐Li , Makino Teruhiko , Abe Riichiro , Matsui Kotaro , Shimizu Hiroshi , Miyamoto Yusei , Kondo Takashi , Shimizu Tadamichi
Published: August 2010

Please cite this paper as: Protective effects of platinum nanoparticles against UV‐light‐induced epidermal inflammation. Experimental Dermatology 2010; 19: 1000–1006.

Abstract:  Intracellular reactive oxygen species (ROS) and apoptosis play important roles in the ultraviolet (UV)‐induced inflammatory responses in the skin. Metal nanoparticles have been developed to increase the catalytic activity of metals, which is because of the large surface area of smaller particles. Platinum nanoparticles (nano‐Pt) protected by poly acrylic acid were manufactured by reduction with ethanol. A marked increase in ROS production was observed in UV‐treated HaCaT keratinocytes cell lines, while a decrease in ROS production was observed in nano‐Pt‐treated cells. Pretreatment of the cells with nano‐Pt also caused a significant inhibition of UVB‐ and UVC‐induced apoptosis. Furthermore, we found that mice treated with nano‐Pt gel prior to UV irradiation showed significant inhibition of UVB‐induced inflammation and UVA‐induced photoallergy compared to UV‐irradiated control mice. These results suggest that nano‐Pt effectively protects against UV‐induced inflammation by decreasing ROS production and inhibiting apoptosis in keratinocytes.
Successful immunoapheresis of bullous autoimmune diseases: pemphigus vulgaris and pemphigoid gestationis
Authors: Marker Michael , Derfler Kurt , Monshi Babak , Rappersberger Klemens
Published: August 2010

Background: Immunoapheresis/immunoadsorption is a specific tool to remove immunoglobulins and immune complexes from the circulation. Immunoapheresis is successfully used in various autoantibody‐mediated diseases (such as autoimmune renal disease and others). In dermatology immunoapheresis is increasingly applied as an adjuvant treatment for severe autoimmune bullous diseases.

Case report: We successfully employed adjuvant immunoapheresis to treat a 57‐year‐old man with life‐threatening pemphigus vulgaris and a 30‐year‐old pregnant woman with severe pemphigoid gestationis. Immunoapheresis induced a rapid improvement and almost complete clearance of clinical symptoms without notable side effects. The clinical improvement was paralleled by a decline of the pathologic circulating autoantibodies. Following stabilization of his disease with immunoapheresis, the pemphigus vulgaris patient was continued on rituximab and remained almost free of symptoms for the next 12 months. The patient with pemphigoid gestationis was subsequently treated with systemic corticosteroids until the symptoms of her self‐limited disease ceased.

Conclusion: Immunoapheresis might represent an excellent therapy for certain patients with severe pemphigus vulgaris or pemphigoid gestationis, unresponsive to conventional treatment regimens. We observed rapid improvement of clinical symptoms and no notable side effects.
Photochemical Formation of Hydroxyl Radicals in Tissue Extracts of the Coral Galaxea fascicularis
Authors: Higuchi Tomihiko , Fujimura Hiroyuki , Hitomi Yuya , Arakaki Takemitsu , Oomori Tamotsu , Suzuki Yoshimi
Published: August 2010

Various stresses induce the formation of reactive oxygen species (ROS) in biological cells. In addition to stress‐induced ROS, we studied the photochemical formation of hydroxyl radicals (˙OH), the most potent ROS, in coral tissues using phosphate buffer‐extracted solutions and a simulated sunlight irradiation system. ˙OH formation was seen in extracts of both coral host and endosymbiont zooxanthellae. This study is the first to report quantitative measurements of ˙OH photoformation in coral tissue extracts. Our results indicated that whether or not coral bleaching occurred, coral tissues and symbiotic zooxanthellae have the potential to photochemically produce ˙OH under sunlight. However, no significant difference was found in the protein content‐normalized formation rates of ˙OH between corals incubated under different temperatures and irradiance conditions. ˙OH formation rates were reduced by 40% by reducing the UV radiation in the illumination. It was indicated that UV radiation strongly affected ˙OH formation in coral tissue and zooxanthellae, in addition to its formation through photoinhibition processes.
Intracellular Antimicrobial Photodynamic Therapy: A Novel Technique for Efficient Eradication of Pathogenic Bacteria
Authors: Nakonechny Faina , Firer Michael A. , Nitzan Yeshayahu , Nisnevitch Marina
Published: August 2010

The increasing resistance of bacteria to antibiotics is a serious problem, caused in part by excessive and improper use of these drugs. One alternative to traditional antibiotic therapy is photodynamic antimicrobial chemotherapy (PACT) which is based on the use of a photosensitizer (PS), activated by illumination with visible light. The poor penetration of visible light through the skin limits the application of PACT to the treatment of skin infections or the use of invasive procedures. To overcome this problem we report the exploitation of light emitted as a result of the chemiluminescent reaction of luminol to excite the PS and we call this process chemiluminescent photodynamic antimicrobial therapy (CPAT). We studied the effect of free and liposome‐encapsulated PS (methylene blue or toluidine blue) on bacteria under excitation by either white external light or chemiluminescence emitted by free or liposome‐enclosed luminol. PACT showed slightly better performance that CPAT for free and encapsulated PS for both types of bacteria. CPAT resulted in a three log suppression of Staphylococcus aureus and two log suppression of Escherichia coli growth. The use of CPAT may prove to be a novel and more effective form of antimicrobial therapy, particularly for internal infections not easily accessible to traditional PACT.
Commercial product exploitation from marine microbial biodiversity: some legal and IP issues
Authors: Tichet Camille , Nguyen Hong Khanh , Yaakoubi Sefia El , Bloch Jean‐François
Published: August 2010

The biodiversity found in the marine environment is remarkable and yet largely unknown compared with the terrestrial one. The associated genetic resource, also wide and unrevealed, has raised a strong interest from the scientific and industrial community. However, despite this growing interest, the discovery of new compounds extracted from marine organisms, more precisely from microorganisms, is ruled by a complex legislation. The access and transfer of genetic resource are ruled by the Convention on Biological Diversity. One of the three core objectives of this convention is to ensure the fair and equitable sharing of benefits generated by the use of genetic resources and to split these benefits between the different stakeholders. From the discovery of a microorganism to the commercialization of a product, three main stakeholders are involved: providers of microorganisms, e.g. academic institutes, the scientists who will perform R&D on biodiversity, and the industrial companies which will commercialize the final product arising from the R&D results. This article describes how difficult and complex it might be to ensure a fair distribution of benefits of this research between the parties.
Downregulation of SIK2 expression promotes the melanogenic program in mice
Authors: Horike Nanao , Kumagai Ayako , Shimono Yuko , Onishi Tomoko , Itoh Yumi , Sasaki Tsutomu , Kitagawa Kazuo , Hatano Osamu , Takagi Hiroaki , Susumu Teruo , Teraoka Hiroshi , Kusano Ken‐ichi , Nagaoka Yasuo , Kawahara Hidehisa , Takemori Hiroshi
Published: August 2010

cAMP response element–binding protein (CREB) promotes melanogenesis by inducing microphthalmia‐associated transcription factor (Mitf ) gene expression. We report here that the CREB‐specific coactivator TORC and its repressor, salt‐inducible kinase 2 (SIK2), are fundamental determinants of the melanogenic program in mice. Exposure of B16 melanoma cells to ultraviolet (UV) light results in the immediate nuclear translocation of TORC1, which is inhibited by SIK2. Overexpression of dominant‐negative TORC1 also inhibits UV‐induced Mitf gene expression and melanogenesis. α‐MSH signaling regulates hair pigmentation, and the decrease in α‐MSH activity in hair follicle melanocytes switches the melanin synthesis from eumelanin (black) to pheomelanin (yellow). Mice with the lethal yellow allele of agouti (Ay) have yellow hair because of impaired activation of the α‐MSH receptor. To examine the involvement of SIK2 in the regulation of the melanogenesis switch in vivo, we prepared SIK2‐knockout mice, and the Sik2−/− genotype was introduced into Ay/a mice. The resultant Sik2−/−; Ay/a mice had brown hair, indicating that SIK2 represses eumelanogenesis in mice.
The identity of Ligularia yui (Asteraceae: Senecioneae) from China
Authors: Ren Chen , Yang Qin‐Er
Published: August 2010

Examination of both macro‐ and micro‐morphological characters have shown that Ligularia yui S. W. Liu is conspecific with Senecio spathiphyllus Franch., and is here reduced to a synonym of the latter species.
Tophaceous gout of the odontoid process causing glossopharyngeal, vagus, and hypoglossal nerve palsies
Authors: TRAN Ai , PRENTICE David , CHAN Madelynn
Published: August 2010

Gout affecting the axial joints is uncommon; however, its involvement may be complicated by neurological symptoms associated with spinal compression at the affected level. Specific involvement of the odontoid process is even rarer. We report the first case of gout involving the odontoid process with resultant glossopharyngeal (CN IX), vagus (CN X) and hypoglossal (CN XII) nerve palsies.
Patient Reported Goal Achievement Following the Midurethral Sling Procedure for Female Stress Urinary Incontinence
Authors: HAN Ji‐Yeon , LEE Young‐Suk , LEE Kyu‐Sung , CHOO Myung‐Soo
Published: August 2010

Objectives: Patient perspective is very important for evaluating surgical outcomes. We investigated patient reported goal achievement, overall satisfaction and objective outcome following the midurethral sling (MUS) procedure for female stress urinary incontinence (SUI).

Methods: The study prospectively enrolled 88 SUI patients who underwent the MUS procedure between August 2006 and December 2006. Patient examination included medical history, physical examination and an urodynamic study prior to surgery. Before surgery, patients were shown a list and asked to nominate one goal which they most wanted to achieve with surgery (i.e., the target goal). The goals were classified as: symptom‐related, daily life‐related, personal relationship‐ and emotion‐related, and others. Before and after the surgery, patients completed a Bristol Female Lower Urinary Tract Symptom‐Short Form questionnaire. At 1 year postoperatively, patients were assessed in terms of achievement of the target goal, overall satisfaction and cure rate.

Results: At the 1‐year follow‐up, overall target goals were achieved in 90.1% of patients, 82 (93.2%) patients were satisfied with the treatment, and 82 (93.2%) patients were cured. For most patients, the target goals were symptom‐related (47 patients, 53.4%). The patients whose goal achievement was less than overall goal achievement were significantly less satisfied than those who fully achieved their goal, and goal achievement was also related to objective cure.

Conclusion: Achievement of patient goals was high and could be a good measure of surgical success following MUS for female SUI.
Direct-write electron beam lithography in silicon dioxide at low energy
Authors: Beaumont Arnaud , Dubuc Christian , Beauvais Jacques , Drouin Dominique
Published: August 2010

Electron beam lithography in silicon dioxide has been investigated with energies ranging from 0.5 up to 6 keV. The etch ratio of SiO2 has been studied and interpreted with regard to the limited penetration of electrons at such low energies. Monte Carlo simulations have been carried out to investigate the depth of penetration and the density of energy absorbed by SiO2. The etch ratio is also shown to depend on the dilution of the developer (a buffered hydrofluoric acid diluted in water). Finally, a possible application of low energy direct writing in silicon dioxide is described for the control of damascene processes, enabling the fabrication of nanodevices embedded in an insulator.
Modeling of precursor coverage in ion-beam induced etching and verification with experiments using XeF2 on SiO2
Authors: Ebm Christoph , Hobler Gerhard , Waid Simon , Wanzenboeck Heinz D.
Published: August 2010

Focused ion beams are an established but inherently slow technique for many nanopatterning applications. One way to increase its processing speed is by gas-assisted ion-beam induced etching. However, to understand and improve this process, the ability to accurately simulate the precursor coverage is very important, because it strongly affects the efficiency of the process. In this paper, the authors present a recoils-based simulation model that considers precursor adsorption, decomposition, and diffusion. The authors provide a non-steady-state solution for translational symmetry, which they use to investigate the influence of the precursor diffusion coefficient on the etching process. They find that the diffusion coefficient influences the shape of the bottom of the irradiated structure. Furthermore, they compare the simulation results to experiments of SiO2 etched by XeF2 using a focused Ga ion beam, and extract model parameters such that the etching rate of numerous experiments with different current densities can be predicted accurately.
Deformable image registration of heterogeneous human lung incorporating the bronchial tree
Authors: Al‐Mayah Adil , Moseley Joanne , Velec Mike , Hunter Shannon , Brock Kristy
Published: August 2010

Purpose:

To investigate the effect of the bronchial tree on the accuracy of biomechanical‐based deformable image registration of human lungs.

Methods:

Three dimensional finite element models have been developed using four dimensional computed tomography image data of ten lung cancer patients. Each model is built of a body, left and right lungs, tumor, and bronchial trees. Triangular shell elements are used for the bronchial trees while tetrahedral elements are used for other components. Hyperelastic material properties based on experimental investigation on human lungs are used for the lung parenchyma. Different material properties are assigned for the bronchial tree using five values for the modulus of elasticity of 0.01, 0.12, 0.5, 10, and 18 MPa. Lungs are modeled to slide inside chest cavities by applying frictionless contact surfaces between each lung and corresponding chest cavity. The accuracy of the models is examined using an average of 40 bronchial bifurcation points identified on inhale and exhale images. Relative accuracy is evaluated by comparing the displacement of all nodes within the lungs as well as the dosimetric difference at the exhale position predicted by the model.

Results:

There is no significant effect of bronchial tree on the model accuracy based on the bifurcation points analysis. However, on the local level, using an average of 38 000 nodes, there is a maximum difference of 8.5 mm in the deformation of the bronchial trees, as the modulus of elasticity of the bronchial trees increases from 0.01 to 18 MPa; however, more than 96% of nodes are within a 2.5 mm difference in each direction. The average dose difference at the predicted exhale position is less than 35 cGy between the models.

Conclusions:

The bronchial tree has little effect on the global deformation and the accuracy of deformable image registration of lungs. Hence, the homogenous model is a reasonable assumption. Since there are some local deformation differences between nodes as the material properties of the bronchial tree change that may affect the accuracy of dosimetric results, heterogeneity may be required for a smaller scale modeling of lungs.
Semiautomatic technique for defining the internal gross tumor volume of lung tumors close to liver/spleen cupola by 4D‐CTa)
Authors: Mancosu Pietro , Sghedoni Roberto , Bettinardi Valentino , Aquilina Mark Anthony , Navarria Piera , Cattaneo Giovanni Mauro , Di Muzio Nadia , Cozzi Luca , Scorsetti Marta
Published: August 2010

Purpose:

It has been shown that in cases of lung tumors close to the liver cupola, the four dimensional (4D)‐CT postprocessing maximum intensity projection (MIP) algorithm does not fully recover the radiotherapy internal gross tumor volume (IGTV). In this work, a semiautomatic technique was evaluated by which the residual IGTV that was not included into the IGTV by MIP algorithm was actually added.

Methods:

A moving phantom and five selected patients were considered. The various IGTVs produced by the semiautomatic approach were compared to those generated by 4D‐CT manual contouring.

Results:

In all cases, the radiation oncologist qualitatively concurred with the semiautomatic IGTV. A quantitative difference in volume of 2.6% was found in the phantom study, whereas a mean difference of was obtained in the patient studies.

Conclusions:

A semiautomatic technique to include the residual part of IGTV covered by liver/spleen cupola when using MIP algorithm was validated on phantom and on selected patients, revealing the possibility of defining the IGTV for patients with lesions located near liver/spleen cupola by performing only the contours on the MIP series.
Response of lithium formate EPR dosimeters at photon energies relevant to the dosimetry of brachytherapy
Authors: Adolfsson Emelie , Alm Carlsson Gudrun , Grindborg Jan‐Erik , Gustafsson Håkan , Lund Eva , Carlsson Tedgren Åsa
Published: August 2010

Purpose:

To investigate experimentally the energy dependence of the detector response of lithium formate EPR dosimeters for photon energies below 1 MeV relative to that at energies. High energy photon beams are used in calibrating dosimeters for use in brachytherapy since the absorbed dose to water can be determined with high accuracy in such beams using calibrated ion chambers and standard dosimetry protocols. In addition to any differences in mass‐energy absorption properties between water and detector, variations in radiation yield (detector response) with radiation quality, caused by differences in the density of ionization in the energy imparted (LET), may exist. Knowledge of an eventual deviation in detector response with photon energy is important for attaining high accuracy in measured brachytherapy dose distributions.

Methods:

Lithium formate EPR dosimeters were irradiated to known levels of air kerma in 25–250 kV x‐ray beams and in and beams at the Swedish Secondary Standards Dosimetry Laboratory. Conversions from air kerma free in air into values of mean absorbed dose to the detectors were made using EGSnrc MC simulations and x‐ray energy spectra measured or calculated for the actual beams. The signals from the detectors were measured using EPR spectrometry. Detector response (the EPR signal per mean absorbed dose to the detector) relative to that for was determined for each beam quality.

Results:

Significant decreases in the relative response ranging from 5% to 6% were seen for x‐ray beams at tube voltages. No significant reduction in the relative response was seen for and 250 kV x rays.

Conclusions:

When calibrated in or MV photon beams, corrections for the photon energy dependence of detector response are needed to achieve the highest accuracy when using lithium formate EPR dosimeters for measuring absorbed doses around brachytherapy sources emitting photons in the energy range of 20–150 keV such as and electronic sources.
Estimation of organ doses from kilovoltage cone‐beam CT imaging used during radiotherapy patient position verification
Authors: Hyer Daniel E. , Hintenlang David E.
Published: August 2010

Purpose:

The purpose of this study was to develop a practical method for estimating organ doses from kilovoltage cone‐beam CT (CBCT) that can be performed with readily available phantoms and dosimeters. The accuracy of organ dose estimates made using the ImPACT patient dose calculator was also evaluated.

Methods:

A 100 mm pencil chamber and standard CT dose index (CTDI) phantoms were used to measure the cone‐beam dose index (CBDI). A weighted CBDIwas then calculated from these measurements to represent the average volumetric dose in the CTDI phantom. By comparingto the previously published organ doses, organ dose conversion coefficients were developed. The measured CBDI values were also used as inputs for the ImPACT calculator to estimate organ doses. All CBDI dose measurements were performed on both the Elekta XVI and Varian OBI at three clinically relevant locations: Head, chest, and pelvis.

Results:

The head, chest, and pelvis protocols yieldedvalues of 0.98, 16.62, and 24.13 mGy for the XVI system and 5.17, 6.14, and 21.57 mGy for the OBI system, respectively. Organ doses estimated with the ImPACT CT dose calculator showed a large range of variation from the previously measured organ doses, demonstrating its limitations for use with CBCT.

Conclusions:

The organ dose conversion coefficients developed in this work relatevalues to organ doses previously measured using the same clinical protocols. Ultimately, these coefficients will allow for the quick estimation of organ doses from routine measurements performed using standard CTDI phantoms and pencil chambers.
Detailed analysis of latencies in image‐based dynamic MLC trackinga)
Authors: Poulsen Per Rugaard , Cho Byungchul , Sawant Amit , Ruan Dan , Keall Paul J.
Published: August 2010

Purpose:

Previous measurements of the accuracy of image‐based real‐time dynamic multileaf collimator (DMLC) tracking show that the major contributor to errors is latency, i.e., the delay between target motion and MLC response. Therefore the purpose of this work was to develop a method for detailed analysis of latency contributions during image‐based DMLC tracking.

Methods:

A prototype DMLC tracking system integrated with a linear accelerator was used for tracking a phantom with an embedded fiducial marker during treatment delivery. The phantom performed a sinusoidal motion. Real‐time target localization was based on x‐ray images acquired either with a portal imager or a kV imager mounted orthogonal to the treatment beam. Each image was stored in a file on the imaging workstation. A marker segmentation program opened the image file, determined the marker position in the image, and transferred it to the DMLC tracking program. This program estimated the three‐dimensional target position by a single‐imager method and adjusted the MLC aperture to the target position. Imaging intervals from 150 to 1000 ms were investigated for both kV and MV imaging. After the experiments, the recorded images were synchronized with MLC log files generated by the MLC controller and tracking log files generated by the tracking program. This synchronization allowed temporal analysis of the information flow for each individual image from acquisition to completed MLC adjustment. The synchronization also allowed investigation of the MLC adjustment dynamics on a considerably finer time scale than the 50 ms time resolution of the MLC log files.

Results:

For, the total time from image acquisition to completed MLC adjustment was for MV and for kV images. The main part of this time was from image acquisition to completed image file writing (272 ms for MV and 309 ms for kV). Image file opening (38 ms), marker segmentation (4 ms), MLC position calculation (16 ms), and MLC adjustment (52 ms) were considerably faster. For , the total time from image acquisition to completed MLC adjustment increased to and mainly because of delayed image file writing. The MLC adjustment duration was constant 52 ms (±3 ms) for MLC adjustments below 1.1 mm and increased linearly for larger MLC adjustments.

Conclusions:

A method for detailed time analysis of each individual real‐time position signal for DMLC tracking has been developed and applied to image‐based tracking. The method allows identification of the major contributors to latency and therefore a focus for reducing this latency. The method could be an important tool for the reconstruction of the delivered target dose during DMLC tracking as it provides synchronization between target motion and MLC motion.
Radiation dose estimation using preclinical imaging with ‐metaiodobenzylguanidine (MIBG) PET
Authors: Lee Chang‐Lae , Wahnishe Hilla , Sayre George A. , Cho Hyo‐Min , Kim Hee‐Joung , Hernandez‐Pampaloni Miguel , Hawkins Randall A. , Dannoon Shorouk F. , VanBrocklin Henry F. , Itsara Melissa , Weiss William A. , Yang Xiaodong , Haas‐Kogan Daphne A. , Matthay Katherine K. , Seo Youngho
Published: August 2010

Purpose:

A pretherapy‐metaiodobenzylguanidine (MIBG) positron emission tomography (PET)/computed tomography (CT) provides a potential method to estimate radiation dose to normal organs, as well as tumors prior to ‐MIBG treatment of neuroblastoma or pheochromocytoma. The aim of this work was to estimate human‐equivalent internal radiation dose of ‐MIBG using PET/CT data in a murine xenograft model.

Methods:

Athymic mice subcutaneously implanted with NB1691 cells that express high levels of human norepinephrine transporter were imaged using small animal microPET/CT over 96 h (approximate imaging time points: 0.5, 2, 24, 52, and 96 h) after intravenous administration of 3.07–4.84 MBq of ‐MIBG via tail vein. The tumors did not accumulate ‐MIBG to a detectable level. All four animals were considered as control and organ radiation dosimetry was performed. Volumes of interest were drawn on the coregistered CT images for thyroid, heart, lung, liver, kidney, and bladder, and transferred to PET images to obtain pharmacokinetic data. Based on tabulated organ mass distributions for both mice and adult male human, preclinical pharmacokinetic data were extrapolated to their human‐equivalent values. Radiation dose estimations for different age groups were performed using the OLINDA|EXM software with modified tissue weighting factors in the recent International Commission on Radiological Protection (ICRP) Publication 103.

Results:

The mean effective dose from‐MIBG using weighting factors from ICRP 103 to the adult male was estimated at 0.25 mSv/MBq. In different age groups, effective doses using values from ICRP 103 were estimated as follows: Adult female: 0.34, 15‐yr‐old: 0.39 mSv/MBq, 10‐yr‐old: 0.58 mSv/MBq, 5‐yr‐old: 1.03 mSv/MBq, 1‐yr‐old: 1.92 mSv/MBq, and newborn: 3.75 mSv/MBq. For comparison, the reported effective dose equivalent of ‐NaI for adult male (25% thyroid uptake, MIRD Dose Estimate Report No. 5) was 6.5 mSv/MBq.

Conclusions:

The authors estimated human‐equivalent internal radiation dose of‐MIBG using preclinical imaging data. As a reference, the effective dose estimation showed that ‐MIBG would deliver less radiation dose than ‐NaI, a radiotracer already being used in patients with thyroid cancer.
Moving target irradiation with fast rescanning and gating in particle therapy
Authors: Furukawa Takuji , Inaniwa Taku , Sato Shinji , Shirai Toshiyuki , Mori Shinichiro , Takeshita Eri , Mizushima Kota , Himukai Takeshi , Noda Koji
Published: August 2010

Purpose:

In moving target irradiation with pencil beam scanning, the interplay effect between the target motion and the scanned beam is a problem because this effect causes over or under dosage in the target volume. To overcome this, we have studied rescanning using a gating technique.

Methods:

A simulation and experimental study was carried out. In the experiment, we used the fast scanning system developed at the HIMAC to verify the validity of phase controlled rescanning method, in which the time for rescanning irradiation of each slice is matched to the gating duration.

Results:

Simulation and experimental results showed that controlling the scan speed to match the respiration cycle with rescans can deliver the blurred dose distribution. In the comparison between the static measurements and the moving measurements with the phase controlled rescanning method, the dose difference was less than 2% for pinpoint chambers in the target volume.

Conclusions:

The simulation and experimental results demonstrated that the phase controlled rescanning method makes it possible to deliver the dose distribution close to the expected one. As an experimental result for 3D irradiation, it was estimated that blurring by the probability density function was not only for a lateral distribution, but also for a distal distribution, even in the lateral rescanning.
Assessment of normal tissue complications following prostate cancer irradiation: Comparison of radiation treatment modalities using NTCP models
Authors: Takam Rungdham , Bezak Eva , Yeoh Eric E. , Marcu Loredana
Published: August 2010

Purpose:

Normal tissue complication probability (NTCP) of the rectum, bladder, urethra, and femoral heads following several techniques for radiation treatment of prostate cancer were evaluated applying the relative seriality and Lyman models.

Methods:

Model parameters from literature were used in this evaluation. The treatment techniques included external (standard fractionated, hypofractionated, and dose‐escalated) three‐dimensional conformal radiotherapy (3D‐CRT), low‐dose‐rate (LDR) brachytherapy (I‐125 seeds), and high‐dose‐rate (HDR) brachytherapy (Ir‐192 source). Dose‐volume histograms (DVHs) of the rectum, bladder, and urethra retrieved from corresponding treatment planning systems were converted to biological effective dose‐based and equivalent dose‐based DVHs, respectively, in order to account for differences in radiation treatment modality and fractionation schedule.

Results:

Results indicated that with hypofractionated 3D‐CRT (20 fractions of 2.75 Gy/fraction delivered five times/week to total dose of 55 Gy), NTCP of the rectum, bladder, and urethra were less than those for standard fractionated 3D‐CRT using a four‐field technique (32 fractions of 2 Gy/fraction delivered five times/week to total dose of 64 Gy) and dose‐escalated 3D‐CRT. Rectal and bladder NTCPs (5.2% and 6.6%, respectively) following the dose‐escalated four‐field 3D‐CRT (2 Gy/fraction to total dose of 74 Gy) were the highest among analyzed treatment techniques. The average NTCP for the rectum and urethra were 0.6% and 24.7% for LDR‐BT and 0.5% and 11.2% for HDR‐BT.

Conclusions:

Although brachytherapy techniques resulted in delivering larger equivalent doses to normal tissues, the corresponding NTCPs were lower than those of external beam techniques other than the urethra because of much smaller volumes irradiated to higher doses. Among analyzed normal tissues, the femoral heads were found to have the lowest probability of complications as most of their volume was irradiated to lower equivalent doses compared to other tissues.
Phantom‐based experimental validation of computational fluid dynamics simulations on cerebral aneurysms
Authors: Sun Qi , Groth Alexandra , Bertram Matthias , Waechter Irina , Bruijns Tom , Hermans Roel , Aach Til
Published: August 2010

Purpose:

Recently, image‐based computational fluid dynamics (CFD) simulation has been applied to investigate the hemodynamics inside human cerebral aneurysms. The knowledge of the computed three‐dimensional flow fields is used for clinical risk assessment and treatment decision making. However, the reliability of the application specific CFD results has not been thoroughly validated yet.

Methods:

In this work, by exploiting a phantom aneurysm model, the authors therefore aim to prove the reliability of the CFD results obtained from simulations with sufficiently accurate input boundary conditions. To confirm the correlation between the CFD results and the reality, virtual angiograms are generated by the simulation pipeline and are quantitatively compared to the experimentally acquired angiograms. In addition, a parametric study has been carried out to systematically investigate the influence of the input parameters associated with the current measuring techniques on the flow patterns.

Results:

Qualitative and quantitative evaluations demonstrate good agreement between the simulated and the real flow dynamics. Discrepancies of less than 15% are found for the relative root mean square errors of time intensity curve comparisons from each selected characteristic position. The investigated input parameters show different influences on the simulation results, indicating the desired accuracy in the measurements.

Conclusions:

This study provides a comprehensive validation method of CFD simulation for reproducing the real flow field in the cerebral aneurysm phantom under well controlled conditions. The reliability of the CFD is well confirmed. Through the parametric study, it is possible to assess the degree of validity of the associated CFD model based on the parameter values and their estimated accuracy range.