Multidisciplinary approach to diagnosis and management of osteosarcoma – a review of the St Vincent's Hospital experience

Background

Osteosarcoma is the most common primary malignant bone tumour in children and young adults. Despite advances in the diagnosis and management of osteosarcoma, there have been few recent studies describing the experiences of tertiary referral centres. This paper aims to describe and discuss the clinical features, pre-operative work-up, management and outcomes of these patients at St Vincent's Hospital (Melbourne, Australia).

Methods

Retrospective study of fifty-nine consecutive patients managed for osteosarcoma at St Vincent's Hospital between 1995 and 2005.

Results

Median age at diagnosis was 21 (range, 11–84) years. Gender distribution was similar, with thirty-one male and twenty-eight female patients.Twenty-five patients had osteosarcoma in the femur, eleven each were located in the humerus and tibia, six were identified in the pelvis, and one each in the clavicle, maxilla, fibula, sacrum, ulna and radius.Pre-operative tissue diagnosis of osteosarcoma was obtained through computed tomography-guided percutaneous biopsy in over ninety percent of patients.Following initial therapy, over fifty percent of patients remained relapse-free during the follow-up period, with twelve percent and twenty-seven percent of patients documented as having local and distant disease recurrence, respectively. Of patients with recurrent disease, sixty-two percent remained disease-free following subsequent surgical intervention (most commonly, pulmonary metastatectomy).

Conclusion

Patient outcomes can be optimised through a multidisciplinary approach in a tertiary referral centre. At St Vincent's Hospital, survival and relapse rates of patients managed for osteosarcoma compare favourably with the published literature.

     

A robust heart sounds segmentation module based on S-transform

This paper presents a new module for heart sounds segmentation based on S-transform. The heart sounds segmentation process segments the PhonoCardioGram (PCG) signal into four parts: S1 (first heart sound), systole, S2 (second heart sound) and diastole. It can be considered one of the most important phases in the auto-analysis of PCG signals. The proposed segmentation module can be divided into three main blocks: localization of heart sounds, boundaries detection of the localized heart sounds and classification block to distinguish between S1 and S2. An original localization method of heart sounds are proposed in this study. The method named SSE calculates the Shannon energy of the local spectrum calculated by the S-transform for each sample of the heart sound signal. The second block contains a novel approach for the boundaries detection of S1 and S2. The energy concentrations of the S-transform of localized sounds are optimized by using a window width optimization algorithm. Then the SSE envelope is recalculated and a local adaptive threshold is applied to refine the estimated boundaries. To distinguish between S1 and S2, a feature extraction method based on the singular value decomposition (SVD) of the S-matrix is applied in this study. The proposed segmentation module is evaluated at each block according to a database of 80 sounds, including 40 sounds with cardiac pathologies.     

An Evolution-Guided Analysis Reveals a Multi-Signaling Regulation of Fas by Tyrosine Phosphorylation and its Implication in Human Cancers

Demonstrations of both pro-apoptotic and pro-survival abilities of Fas (TNFRSF6/CD95/APO-1) have led to a shift from the exclusive “Fas apoptosis” to “Fas multisignals” paradigm and the acceptance that Fas-related therapies face a major challenge, as it remains unclear what determines the mode of Fas signaling. Through protein evolution analysis, which reveals unconventional substitutions of Fas tyrosine during divergent evolution, evolution-guided tyrosine-phosphorylated Fas proxy, and site-specific phosphorylation detection, we show that the Fas signaling outcome is determined by the tyrosine phosphorylation status of its death domain. The phosphorylation dominantly turns off the Fas-mediated apoptotic signal, while turning on the pro-survival signal. We show that while phosphorylations at Y232 and Y291 share some common functions, their contributions to Fas signaling differ at several levels. The findings that Fas tyrosine phosphorylation is regulated by Src family kinases (SFKs) and the phosphatase SHP-1 and that Y291 phosphorylation primes clathrin-dependent Fas endocytosis, which contributes to Fas pro-survival signaling, reveals for the first time the mechanistic link between SFK/SHP-1-dependent Fas tyrosine phosphorylation, internalization route, and signaling choice. We also demonstrate that levels of phosphorylated Y232 and Y291 differ among human cancer types and differentially respond to anticancer therapy, suggesting context-dependent involvement of Fas phosphorylation in cancer. This report provides a new insight into the control of TNF receptor multisignaling by receptor phosphorylation and its implication in cancer biology, which brings us a step closer to overcoming the challenge in handling Fas signaling in treatments of cancer as well as other pathologies such as autoimmune and degenerative diseases.     

Immunohistochemical localization of irisin in skin,eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata)

Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity.     

Selective expansion of the newly evolved genomic variants of retrotransposon 1731 in the Drosophila genomes

The structural variants of the regulatory and coding regions of the LTR-retrotransposon 1731 are described. Two classes of genomic copies of retrotransposon 1731, with and without frameshifting strategy to express Gag and Pol proteins, were earlier revealed in the D. melanogaster genome. Copies without frameshifting are shown to be evolved from an ancient variant with frameshifting and are widespread in the genomes of the melanogaster complex species. Position of a rare codon responsible for ribosome pausing and efficient frameshifting is identified. Two structural variants of 1731 LTRs were detected in the melanogaster complex species: the predominant structural variant A1A2 of 1731 LTR in the D. melanogaster, D. simulans, and D. sechellia genomes contains duplicated and diverged copies of 28 bp in the U3 region, whereas A1 variant lacking this duplication is expanded in the D. mauritiana genome. Selective expansion of the A1A2 variant was detected in the independently established D. melanogaster cell cultures. A1A2 variant is expressed in embryos, cell culture, and testes, whereas A1 is expressed only in testes of D. melanogaster. Relief of expression of the A1A2 but not A1 variant in the ovaries as a result of mutation in the RNA interference (RNAi) spn-E gene is shown. Thus, expansion of the recently evolved genomic variants of the LTR retrotransposon 1731 possessing a new translation strategy, duplication in the U3 region, and extended profile of expression is revealed.     

Assessing the role of the T cell receptor beta gene enhancer in regulating coding joint formation during V(D)J recombination

To assess the role of the T cell receptor (TCR) beta gene enhancer (Ebeta) in regulating the processing of VDJ recombinase-generated coding ends, we assayed TCRbeta rearrangement of Ebeta-deleted (DeltaEbeta) thymocytes in which cell death is inhibited via expression of a Bcl-2 transgene. Compared with DeltaEbeta, DeltaEbeta Bcl-2 thymocytes show a small accumulation of TCRbeta standard recombination products, including coding ends, that involves the proximal Dbeta-Jbeta and Vbeta14 loci but not the distal 5' Vbeta genes. These effects are detectable in double negative pro-T cells, predominate in double positive pre-T cells, and correlate with regional changes in chromosomal structure during double negative-to-double positive differentiation. We propose that Ebeta, by driving long range nucleoprotein interactions and the control of locus expression and chromatin structure, indirectly contributes to the stabilization of coding ends within the recombination processing complexes. The results also illustrate Ebeta-dependent and -independent changes in chromosomal structure, suggesting distinct modes of regulation of TCRbeta allelic exclusion depending on the position within the locus.     

Screening library evolution through automation of solution preparation

The quality of the compound library is a critical success factor in every high-throughput screening campaign. Screening solutions have to be prepared with a high level of process control to ensure the correct identity and initial concentration of each compound. However, even under optimized storage conditions, a certain level of degradation in solution cannot be avoided. Therefore, regular quality control and eventual removal of solutions from the screening deck is necessary. Because solution preparation, especially the weighing of compounds, is a tedious and often manual task, a regular resolubilization of compounds is difficult to achieve. By complete automation of the solution preparation, the authors have laid the foundation for a life cycle management of screening solutions. They demonstrate how a combination of quality and process control leads to a continuous improvement of the screening library. In presenting an automation concept, they show how a series of innovative process optimizations led to a high-performance system that achieves full industrialization of solution preparation.