665 research outputs found
CD133+ Anaplastic Thyroid Cancer Cells Initiate Tumors in Immunodeficient Mice and Are Regulated by Thyrotropin
Anaplastic thyroid cancer (ATC) is one of the most lethal human malignancies. Its rapid onset and resistance to conventional therapeutics contribute to a mean survival of six months after diagnosis and make the identification of thyroid-cancer-initiating cells increasingly important.In prior studies of ATC cell lines, CD133(+) cells exhibited stem-cell-like features such as high proliferation, self-renewal and colony-forming ability in vitro. Here we show that transplantation of CD133(+) cells, but not CD133(-) cells, into immunodeficient NOD/SCID mice is sufficient to induce growth of tumors in vivo. We also describe how the proportion of ATC cells that are CD133(+) increases dramatically over three months of culture, from 7% to more than 80% of the total. This CD133(+) cell pool can be further separated by flow cytometry into two distinct populations: CD133(+/high) and CD133(+/low). Although both subsets are capable of long-term tumorigenesis, the rapidly proliferating CD133(+/high) cells are by far the most efficient. They also express high levels of the stem cell antigen Oct4 and the receptor for thyroid stimulating hormone, TSHR. Treating ATC cells with TSH causes a three-fold increase in the numbers of CD133(+) cells and elicits a dose-dependent up-regulation of the expression of TSHR and Oct4 in these cells. More importantly, immunohistochemical analysis of tissue specimens from ATC patients indicates that CD133 is highly expressed on tumor cells but not on neighboring normal thyroid cells.To our knowledge, this is the first report indicating that CD133(+) ATC cells are solely responsible for tumor growth in immunodeficient mice. Our data also give a unique insight into the regulation of CD133 by TSH. These highly tumorigenic CD133(+) cells and the activated TSH signaling pathway may be useful targets for future ATC therapies
Genome-wide copy number variation study in anorectal malformations
Anorectal malformations (ARMs, congenital obstruction of the anal opening) are among the most common birth defects requiring surgical treatment (2-5/10 000 live-births) and carry significant chronic morbidity. ARMs present either as isolated or as part of the phenotypic spectrum of some chromosomal abnormalities or monogenic syndromes. The etiology is unknown. To assess the genetic contribution to ARMs, we investigated single-nucleotide polymorphisms and copy number variations (CNVs) at genome-wide scale. A total of 363 Han Chinese sporadic ARM patients and 4006 Han Chinese controls were included. Overall, we detected a 1.3-fold significant excess of rare CNVs in patients. Stratification of patients by presence/absence of other congenital anomalies showed that while syndromic ARM patients carried significantly longer rare duplications than controls (P = 0.049), non-syndromic patients were enriched with both rare deletions and duplications when compared with controls (P = 0.00031). Twelve chromosomal aberrations and 114 rare CNVs were observed in patients but not in 868 controls nor 11 943 healthy individuals from the Database of Genomic Variants. Importantly, these aberrations were observed in isolated ARM patients. Gene-based analysis revealed 79 genes interfered by CNVs in patients only. In particular, we identified a de novo DKK4 duplication. DKK4 is a member of the WNT signaling pathway which is involved in the development of the anorectal region. In mice, Wnt disruption results in ARMs. Our data suggest a role for rare CNVs not only in syndromic but also in isolated ARM patients and provide a list of plausible candidate genes for the disorder.postprin
Smart garment for trunk posture monitoring: A preliminary study
© 2008 Wong and Wong; licensee BioMed Central Ltd
Protein Disulfide Isomerase Regulates Endoplasmic Reticulum Stress and the Apoptotic Process during Prion Infection and PrP Mutant-Induced Cytotoxicity
<div><h3>Background</h3><p>Protein disulfide isomerase (PDI), is sorted to be enzymatic chaperone for reconstructing misfolded protein in endoplasmic reticulum lumen. Recently, PDI has been identified as a link between misfolded protein and neuron apoptosis. However, the potential for PDI to be involved in the pathogenesis of prion disease remains unknown. In this study, we propose that PDI may function as a pleiotropic regulator in the cytotoxicity induced by mutated prion proteins and in the pathogenesis of prion diseases.</p> <h3>Methodology/Principal Findings</h3><p>To elucidate potential alterations of PDI in prion diseases, the levels of PDI and relevant apoptotic executors in 263K infected hamsters brain tissues were evaluated with the use of Western blots. Abnormal upregulation of PDI, Grp78 and Grp58 was detected. Dynamic assays of PDI alteration identified that the upregulation of PDI started at the early stage and persistently increased till later stage. Obvious increases of PDI and Grp78 levels were also observed in cultured cells transiently expressing PrP mutants, PrP-KDEL or PrP-PG15, accompanied by significant cytotoxicities. Excessive expression of PDI partially eased ER stress and cell apoptosis caused by accumulation of PrP-KDEL, but had less effect on cytotoxicity induced by PrP-PG15. Knockdown of endogenous PDI significantly amended cytotoxicity of PrP-PG15, but had little influence on that of PrP-KDEL. A series of membrane potential assays found that apoptosis induced by misfolded PrP proteins could be regulated by PDI via mitochondrial dysfunction. Moreover, biotin-switch assays demonstrated active <em>S</em>-nitrosylted modifications of PDI (SNO-PDI) both in the brains of scrapie-infected rodents and in the cells with misfolded PrP proteins.</p> <h3>Conclusion/Significance</h3><p>Current data in this study highlight that PDI and its relevant executors may function as a pleiotropic regulator in the processes of different misfolded PrP proteins and at different stages during prion infection. SNO-PDI may feed as an accomplice for PDI apoptosis.</p> </div
Waist circumference and waist-to-height ratio of Hong Kong Chinese children
<p>Abstract</p> <p>Background</p> <p>Central body fat is a better predictor than overall body fat for cardiovascular (CV) risk factors in both adults and children. Waist circumference (WC) has been used as a proxy measure of central body fat. Children at high CV risk may be identified by WC measurements. Waist-to-height ratio (WHTR) has been proposed as an alternative, conveniently age-independent measure of CV risk although WHTR percentiles have not been reported. We aim to provide age- and sex-specific reference values for WC and WHTR in Hong Kong Chinese children.</p> <p>Methods</p> <p>Cross sectional study in a large representative sample of 14,842 children aged 6 to 18 years in 2005/6. Sex-specific descriptive statistics for whole-year age groups and smoothed percentile curves of WC and WHTR were derived and presented.</p> <p>Results</p> <p>WC increased with age, although less after age 14 years in girls. WHTR decreased with age (particularly up to age 14). WHTR correlated less closely than WC with BMI (r = 0.65, 0.59 cf. 0.93, 0.91, for boys and girls respectively).</p> <p>Conclusion</p> <p>Reference values and percentile curves for WC and WHRT of Chinese children and adolescents are provided. Both WC and WHTR are age dependent. Since the use of WHRT does not obviate the need for age-related reference standards, simple WC measurement is a more convenient method for central fat estimation than WHRT.</p
Business process management and supply chain collaboration: a critical comparison
The link between a firm and supply chain (SC) members has been recognised as one of the key issues for ensuring business success and achieving competitive advantage. Indeed, working across organisational boundaries is required to accomplish effective responses to customers’ needs. Our preliminary research confirmed that there are positive relationships between business process management (BPM), supply chain collaboration (SCC), collaborative advantage and organisational performance. This study is a step further and uses a multiple case design to illuminate the results and gain a greater understanding from extensive discussions about these relationships. By means of semi-structured interviews, the three main issues were identified as: (1) the link between BPM and organisational performance; (2) the link between BPM and SCC; and (3) the contextual factors and benefits achieved from working collaboratively with SC partners. The different scenarios of the link between BPM and SCC were developed in a taxonomy, and the case studies were used to illustrate the experience of intra- and inter-organisational practices in the developing economy of Thailand. The case studies’ results explain in depth that both BPM and SCC are important for improving organisational performance and competitiveness. BPM not only improves organisational performance directly, but also assists with collaborative activities that in turn help to improve internal capabilities. Additionally, the comparisons in issues relating to firm size, industry type, relationship closeness and relationship length were also included in this study
In Vitro Identification and Characterization of CD133pos Cancer Stem-Like Cells in Anaplastic Thyroid Carcinoma Cell Lines
Background: Recent publications suggest that neoplastic initiation and growth are dependent on a small subset of cells,
termed cancer stem cells (CSCs). Anaplastic Thyroid Carcinoma (ATC) is a very aggressive solid tumor with poor prognosis,
characterized by high dedifferentiation. The existence of CSCs might account for the heterogeneity of ATC lesions. CD133
has been identified as a stem cell marker for normal and cancerous tissues, although its biological function remains
unknown.
Methodology/Principal Findings: ATC cell lines ARO, KAT-4, KAT-18 and FRO were analyzed for CD133 expression. Flow
cytometry showed CD133pos cells only in ARO and KAT-4 (6469% and 57612%, respectively). These data were confirmed by
qRT-PCR and immunocytochemistry. ARO and KAT-4 were also positive for fetal marker oncofetal fibronectin and negative
for thyrocyte-specific differentiating markers thyroglobulin, thyroperoxidase and sodium/iodide symporter. Sorted ARO/
CD133pos cells exhibited higher proliferation, self-renewal, colony-forming ability in comparison with ARO/CD133neg.
Furthermore, ARO/CD133pos showed levels of thyroid transcription factor TTF-1 similar to the fetal thyroid cell line TAD-2,
while the expression in ARO/CD133neg was negligible. The expression of the stem cell marker OCT-4 detected by RT-PCR
and flow cytometry was markedly higher in ARO/CD133pos in comparison to ARO/CD133neg cells. The stem cell markers c-
KIT and THY-1 were negative. Sensitivity to chemotherapy agents was investigated, showing remarkable resistance to
chemotherapy-induced apoptosis in ARO/CD133pos when compared with ARO/CD133neg cells.
Conclusions/Significance: We describe CD133pos cells in ATC cell lines. ARO/CD133pos cells exhibit stem cell-like features -
such as high proliferation, self-renewal ability, expression of OCT-4 - and are characterized by higher resistance to
chemotherapy. The simultaneous positivity for thyroid specific factor TTF-1 and onfFN suggest they might represent
putative thyroid cancer stem-like cells. Our in vitro findings might provide new insights for novel therapeutic approaches
Using system dynamics for collaborative design: a case study
<p>Abstract</p> <p>Background</p> <p>In order to facilitate the collaborative design, system dynamics (SD) with a group modelling approach was used in the early stages of planning a new stroke unit. During six workshops a SD model was created in a multiprofessional group.</p> <p>Aim</p> <p>To explore to which extent and how the use of system dynamics contributed to the collaborative design process.</p> <p>Method</p> <p>A case study was conducted using several data sources.</p> <p>Results</p> <p>SD supported a collaborative design, by facilitating an explicit description of stroke care process, a dialogue and a joint understanding. The construction of the model obliged the group to conceptualise the stroke care and experimentation with the model gave the opportunity to reflect on care.</p> <p>Conclusion</p> <p>SD facilitated the collaborative design process and should be integrated in the early stages of the design process as a quality improvement tool.</p
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