Linear, weakly nonlinear and fully nonlinear models for soft tissues: which ones provide the most reliable estimations of the stiffness?

Benign and malignant lesions in tissues or organs can be detected by elastographic investigations in which pathological regions are spotted from local alterations of the stiffness. As is known, the shear modulus provides a measure of the stiffness of an elastic material. Based on the classical theory of linear elasticity, an elastogram yields estimations of the linear shear modulus from measurements of the speed of small-amplitude transverse waves propagating in the medium tested. In this paper, we show that the estimation of the shear modulus can be improved significantly by employing the fourth-order weakly nonlinear theory of elasticity (FOE), and indicate how the stiffness can be assessed more precisely with the use of FOE. We discuss also why FOE provides more reliable results than the fully nonlinear theory of elasticity. This article is part of the theme issue 'The Ogden model of rubber mechanics: Fifty years of impact on nonlinear elasticity'.

Severe acute colitis related to levodopa treatment.

The first case of severe drug-induced gastrointestinal injury related to levodopa is described. The 86-year-old patient experienced acute colitis temporally related to the intake of the drug with complete resolution of symptoms on levodopa withdrawal. Awareness of the possibility of a levodopa-related damage on colon biopsies performed for acute colitis is of paramount importance for pathologists. However, in order to exclude or confirm a drug-related damage an effective communications between clinicians and pathologists is always required.

Insulin production and resistance in cystic fibrosis: effect of age, disease activity, and genotype.

AIM: To assess the major determinants of glucose tolerance between age, genotype, and clinical status in cystic fibrosis (CF) patients, and study if defects of insulin secretion and insulin sensitivity were associated with the onset of CF-related diabetes (CFRD). SUBJECTS AND METHODS: One hundred and nineteen patients, in stable clinical condition were studied. They were subdivided into 3 groups based on age, and 2 groups based on Schwachman-Kulczycki clinical score. All patients were genotyped, and subsequently divided into 3 groups. Ninety-four healthy normal-weight controls, comparable for sex and age were also studied. All subjects had baseline blood samples taken for glucose and insulin, C-peptide, and glycated hemoglobin. Homeostasis model assessment of insulin resistance (HOMA-IR), fasting glucose/insulin ratio (FGIR) were calculated as indices of IR and insulinogenic index as a marker of pancreatic ß-cell function. All patients underwent an oral glucose tolerance test, and 57 underwent an IVGTT for the calculation of first-phase (FPIR) and acute insulin responses (AIR). RESULTS: The F508del homozygous patients had an increased chance of developing impaired glucose tolerance (IGT) and significantly lower FPIR, decreased HOMA-IR, and insulinogenic index. Heterozygote F508del patients had an increased chance of having normal glucose tolerance. HOMA-IR, FGIR, and insulinogenic index did not change with age or clinical score. HOMAIR correlated with FPIR. FPIR correlated positively with insulinogenic index. AIR correlated negatively with FGIR, and positively with C-reactive protein. In multiple linear regression analyses, glucose tolerance was related to the agegroup, and to the HOMA-IR and insulinogenic indexes. CONCLUSIONS: IGT and CFRD were related mainly to genotype, although, as expected, the prevalence increased with age. The data suggested a possible combined contribution of insulin deficiency, ß-cell function, and reduced insulin sensitivity to the onset of CFRD; however, further studies are warranted to better elucidate this aspect.

ß-HHVs and HHV-8 in Lymphoproliferative Disorders.

Similarly to Epstein-Barr virus (EBV), the human herpesvirus-8 (HHV-8) is a γ-herpesvirus, recently recognized to be associated with the occurrence of rare B cell lymphomas and atypical lymphoproliferations, especially in the human immunodeficiency virus (HIV) infected subjects. Moreover, the human herpesvirus-6 (HHV-6), a ß-herpesvirus, has been shown to be implicated in some non-malignant lymph node proliferations, such as the Rosai Dorfman disease, and in a proportion of Hodgkin's lymphoma cases. HHV-6 has a wide cellular tropism and it might play a role in the pathogenesis of a wide variety of human diseases, but given its ubiquity, disease associations are difficult to prove and its role in hematological malignancies is still controversial. The involvement of another ß-herpesvirus, the human cytomegalovirus (HCMV), has not yet been proven in human cancer, even though recent findings have suggested its potential role in the development of CD4(+) large granular lymphocyte (LGL) lymphocytosis. Here, we review the current knowledge on the pathogenetic role of HHV-8 and human ß-herpesviruses in human lymphoproliferative disorders.

Avaliação da dosagem de própolis pulverizada nas folhas de amoreira (morus sp.) sobre o desenvolvimento biológico e produtivo do bicho-da-seda (bombyx mori L. ) / Evaluación de la dosis de propóleos esparcidas en las hojas de morera (morus sp.) en el desarrollo biológico y productivo del gusano de seda (bombyx mori L.) / Evaluation of the doses of propolis pulverization in mulberry leaves (morus sp.) on the biological and productive development of silkworm (bombyx mori L.)

Este experimento foi realizado no Laboratório de Sericicultura, no Campus Sede da Universidade Paranaense (UNIPAR) de Umuarama, no período de 17/09/2009 a 17/10/2009, com o objetivo de verificar o efeito da própolis em diferentes dosagens na alimentação durante o desenvolvimento biológico do bicho-da-seda (Bombxy mori L). O método empregado na parte experimental foi a pulverização do extrato alcoólico de própolis, diluído em 500 mL de água destilada nas folhas de amoreira, nas seguintes dosagens, água-controle, 5mL, 10mL, 15mL e 20mL compondo os tratamentos T1, T2, T3, T4, T5, respectivamente. As folhas de amoreira foram fornecidas cinco vezes ao dia, durante o manejo alimentar. Verificou-se pelos resultados obtidos, que as diferentes dosagens de própolis utilizadas interferem no ganho de peso das lagartas, no peso dos casulos verdes e crisálidas quando comparado ao tratamento controle, influenciando também no número de casulos formados e, para os teores de seda bruto e líquido não apresentaram resultados significativos, quando comparados com o tratamento controle. Portanto, verificou-se que a própolis, nas dosagens utilizadas, não trouxe efeitos depressivos à biologia e produção do bicho-da-seda.

This experiment was conducted at the Sericulture Laboratory, in the Campus Sede of the Universidade Paranaense (UNIPAR) in Umuarama, from 17/09/2009 to 17/10/2009, in order to verify the effects of propolis in different dosages during the development of silkworm (Bombyx mori L). The method used during the experiment was the dillution of an alcohoolic solution of propolis, in 500 mL of destilled water with its further pulverization on mullberry leaves, with the following doses: water control; 5 mL; 10 mL; 15 mL; 20 mL, composing the following treatments: T1, T2, T3, T4, T5, respectively. The mullberry leaves were sprinkled five times a day, during the feed management. It was verified by the results that the different doses of propolis used interfere with gain-weight of the larvae, weight of cocoons and chrysalis, when compared to control. The treatment also influenced the number of cocoons formed. The contento fraw and liquid silk were not significant when compared with the control. Therefore, it was concluded that the propolis, used in those dosages, brought no depressive effects to the development and the production of silkworm.

Este experimento se realizó en el Laboratorio de Sericicultura del Campus Sede de la Universidad Paranaense (UNIPAR) de Umuarama, en el período de 17/09/2009 a 17/10/2009, con el objetivo de verificar el efecto de propóleos en diferentes dosis en la alimentación durante el desarrollo biológico del gusano de seda (Bombyx mori L.). El método usado en la parte experimental fue la pulverización del extracto alcohólico de propóleos, diluido en 500 ml de agua destilada en las hojas de morera, en las siguientes dosis: agua control, 5 ml, 10 ml, 15 ml y 20 ml componiendo los tratamientos T1, T2, T3, T4, T5, respectivamente. Las hojas de morera fueron suministradas cinco veces al día, durante el manejo alimentar. Por los resultados obtenidos se verificó que las dosis diferentes de propóleos utilizadas interfieren en el gano de peso de los gusanos, en el peso de los capullos verdes y crisálidas cuando comparado al tratamiento control, influenciando también en el número de capullos formados y, para contenidos de seda bruta y líquida no presentan resultados significativos, mientras comparado con el tratamiento control. Sin embargo, se puede verificar que propóleos, en dosis utilizadas, no trajo efectos depresivos a la biología y producción del gusano.

Radiograph-based femur morphing method.

Many applications in orthopaedic surgery require the creation of personalised design models that can serve as the basis for navigation in computer aided surgery systems or be used to create a personalised model to perform structural analysis during pre-operative planning or post-operative follow-up. The paper introduces a method for developing a three-dimensional (3D) patient-specific model of a femur bone from an antero-posterior radiograph. A generic femur was employed and was altered on the basis of bone boundaries visible on radiographs. Morphological errors were evaluated against 3D models obtained from computed tomography (CT) scans. When only the antero-posterior radiograph was used, the average radius estimation error was 4.8 mm, the average percentage area estimation error was 14%, and the average percentage estimation error for inertial moments was 15%. If both the medial-lateral and the anterior-posterior radiographs were used, these errors were 2.0 mm, 5% and 7%, respectively. The procedure described can be profitably employed whenever CT scans are not available, such as during a retrospective analysis, or when CT scans cannot be justified because of X-ray exposure and cost considerations.