90 research outputs found

    Radiation Impairs Perineural Invasion by Modulating the Nerve Microenvironment

    Get PDF
    Perineural invasion (PNI) by cancer cells is an ominous clinical event that is associated with increased local recurrence and poor prognosis. Although radiation therapy (RT) may be delivered along the course of an invaded nerve, the mechanisms through which radiation may potentially control PNI remain undefined. murine sciatic nerve model was used to study how RT to nerve or cancer affects nerve invasion by cancer.Cancer cell invasion of the DRG was partially dependent on DRG secretion of glial-derived neurotrophic factor (GDNF). A single 4 Gy dose of radiation to the DRG alone, cultured with non-radiated cancer cells, significantly inhibited PNI and was associated with decreased GDNF secretion but intact DRG viability. Radiation of cancer cells alone, co-cultured with non-radiated nerves, inhibited PNI through predominantly compromised cancer cell viability. In a murine model of PNI, a single 8 Gy dose of radiation to the sciatic nerve prior to implantation of non-radiated cancer cells resulted in decreased GDNF expression, decreased PNI by imaging and histology, and preservation of sciatic nerve motor function.Radiation may impair PNI through not only direct effects on cancer cell viability, but also an independent interruption of paracrine mechanisms underlying PNI. RT modulation of the nerve microenvironment may decrease PNI, and hold significant therapeutic implications for RT dosing and field design for patients with cancers exhibiting PNI

    Changes in Parasite Virulence Induced by the Disruption of a Single Member of the 235 kDa Rhoptry Protein Multigene Family of Plasmodium yoelii

    Get PDF
    Invasion of the erythrocyte by the merozoites of the malaria parasite is a complex process involving a range of receptor-ligand interactions. Two protein families termed Erythrocyte Binding Like (EBL) proteins and Reticulocyte Binding Protein Homologues (RH) play an important role in host cell recognition by the merozoite. In the rodent malaria parasite, Plasmodium yoelii, the 235 kDa rhoptry proteins (Py235) are coded for by a multigene family and are members of the RH. In P. yoelii Py235 as well as a single member of EBL have been shown to be key mediators of virulence enabling the parasite to invade a wider range of host erythrocytes. One member of Py235, PY01365 is most abundantly transcribed in parasite populations and the protein specifically binds to erythrocytes and is recognized by the protective monoclonal antibody 25.77, suggesting a key role of this particular member in virulence. Recent studies have indicated that overall levels of Py235 expression are essential for parasite virulence. Here we show that disruption of PY01365 in the virulent YM line directly impacts parasite virulence. Furthermore the disruption of PY01365 leads to a reduction in the number of schizonts that express members of Py235 that react specifically with the mcAb 25.77. Erythrocyte binding assays show reduced binding of Py235 to red blood cells in the PY01365 knockout parasite as compared to YM. While our results identify PY01365 as a mediator of parasite virulence, they also confirm that other members of Py235 are able to substitute for PY01365

    Human Rights Shaming Through INGOs and Foreign Aid Delivery

    Get PDF
    Does the ``shaming" of human rights violations influence foreign aid delivery decisions across OECD donor countries? We examine the effect of shaming, defined as targeted negative attention by human rights international nongovernmental organizations (INGOs), on donor decisions about how to deliver bilateral aid. We argue that INGO shaming of recipient countries leads donor governments, on average, to ``bypass" the recipient government in favor of non-state aid delivery channels, including international and local NGOs and international organizations (IOs). However, we expect this relationship to be conditional on a donor country's position in the international system. Minor power countries have limited influence in global affairs and are therefore more able to centrally promote human rights in their foreign policy. Major power countries, on the other hand, shape world politics and often confront ``realpolitik" concerns that may require government-to-government aid relations in the presence of INGO shaming. We expect aid officials of minor donor countries to be more likely to condition aid delivery decisions on human rights shaming than their counterparts of major donor countries. Using compositional data analysis, we test our argument using originally collected data on human rights shaming events in a time-series cross-sectional framework from 2004 to 2010. We find support for our hypotheses: On average, OECD donor governments increase the proportion of bypass when INGOs shame the recipient government. When differentiating between donor types we find that this finding holds for minor but not for major powers. These results add to both our understanding of the influences of aid allocation decision-making and our understanding of the role of INGOs on foreign-policy

    A Practical Approach to the Secure Computation of the Moore-Penrose Pseudoinverse over the Rationals

    Get PDF
    Solving linear systems of equations is a universal problem. In the context of secure multiparty computation (MPC), a method to solve such systems, especially for the case in which the rank of the system is unknown and should remain private, is an important building block. We devise an efficient and data-oblivious algorithm (meaning that the algorithm\u27s execution time and branching behavior are independent of all secrets) for solving a bounded integral linear system of unknown rank over the rational numbers via the Moore-Penrose pseudoinverse, using finite-field arithmetic. I.e., we compute the Moore-Penrose inverse over a finite field of sufficiently large order, so that we can recover the rational solution from the solution over the finite field. While we have designed the algorithm with an MPC context in mind, it could be valuable also in other contexts where data-obliviousness is required, like secure enclaves in CPUs. Previous work by Cramer, Kiltz and Padró (CRYPTO 2007) proposes a constant-rounds protocol for computing the Moore-Penrose pseudoinverse over a finite field. The asymptotic complexity (counted as the number of secure multiplications) of their solution is O(m4+n2m)O(m^4 + n^2 m), where mm and nn, m≤nm\leq n, are the dimensions of the linear system. To reduce the number of secure multiplications, we sacrifice the constant-rounds property and propose a protocol for computing the Moore-Penrose pseudoinverse over the rational numbers in a linear number of rounds, requiring only O(m2n)O(m^2n) secure multiplications. To obtain the common denominator of the pseudoinverse, required for constructing an integer-representation of the pseudoinverse, we generalize a result by Ben-Israel for computing the squared volume of a matrix. Also, we show how to precondition a symmetric matrix to achieve generic rank profile while preserving symmetry and being able to remove the preconditioner after it has served its purpose. These results may be of independent interest

    Removal of migrated metallic prostatic stent by holmium laser

    No full text
    A 90-year-old male with prostatic hyperplasia with a history of ischemic heart disease and right-sided hemiplegia had undergone a Urolume stent placement because of acute urinary retention 9 months earliar. The stent had migrated into the bladder causing dysuria and a poor stream of urine. We fragmented the prostatic stent by Holmium (HO: YAG) laser followed by a laser prostatectomy. After the procedure, the patient voided satisfactorily

    Prognostic value of molecular markers, sub-stage and European Organisation for the Research and Treatment of Cancer risk scores in primary T1 bladder cancer

    No full text
    OBJECTIVE To evaluate the prognostic significance of four molecular markers, sub-stage and European Organisation for the Research and Treatment of Cancer (EORTC) risk scores in primary T1 bladder cancer (BC) treated with adjuvant bacille Calmette-Guerin. PATIENTS AND METHODS The slides of 129 carcinomas of the bladder from two university hospitals were reviewed and the T1 diagnosis was confirmed. T1 sub-staging was done in two separate rounds, using a new system that identifies micro-invasive (T1m) and extensive-invasive (T1e) T1BC, and then according to invasion of the muscularis mucosae (T1a/T1b/T1c). The EORTC risk scores for recurrence and progression were calculated. Uni- and multivariable analyses for recurrence and progression were performed using clinicopathological variables, T1 sub-stage, EORTC risk scores and molecular markers (fibroblast growth factor receptor 3 gene mutation and Ki-67, P53, P27 expression). RESULTS The median follow-up was 6.5 years. Forty-two patients remained recurrence-free (33%). Progression to T2 or metastasis was observed in 38 (30%) patients. In multivariable analysis for recurrence, multiplicity was significant. In multivariable analysis for progression, female gender, sub-stage (T1m/T1e) and carcinoma in situ (CIS) were significant. Molecular markers were significant in univariable and in multivariable analyses for recurrence. EORTC risk scores were not significant. CONCLUSIONS CIS, female gender and sub-stage (T1m/T1e) were the most important variables for progression. The additional value of molecular markers was modest. Sub-stage (T1m/T1e) could potentially be incorporated in future tumour-node-metastasis classifications
    • …
    corecore