11 research outputs found

    Birational geometry of hypersurfaces in products of projective spaces

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    We study the birational properties of hypersurfaces in products of projective spaces. In the case of hypersurfaces in Pm x Pn, we describe their nef, movable and e ective cones and determine when they are Mori dream spaces. Using this, we give new simple examples of non-Mori dream spaces and analogues of Mumford's example of a strictly nef line bundle which is not ample.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00209-015-1415-

    Osteosarcoma microenvironment: whole-slide imaging and optimized antigen detection overcome major limitations in immunohistochemical quantification.

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    BACKGROUND: In osteosarcoma survival rates could not be improved over the last 30 years. Novel biomarkers are warranted to allow risk stratification of patients for more individual treatment following initial diagnosis. Although previous studies of the tumor microenvironment have identified promising candidates, novel biomarkers have not been translated into routine histopathology. Substantial difficulties regarding immunohistochemical detection and quantification of antigens in decalcified and heterogeneous osteosarcoma might largely explain this translational short-coming. Furthermore, we hypothesized that conventional hot spot analysis is often not representative for the whole section when applied to heterogeneous tissues like osteosarcoma. We aimed to overcome these difficulties for major biomarkers of the immunovascular microenvironment. METHODS: Immunohistochemistry was systematically optimized for cell surface (CD31, CD8) and intracellular antigens (FOXP3) including evaluation of 200 different antigen retrieval conditions. Distribution patterns of these antigens were analyzed in formalin-fixed and paraffin-embedded samples from 120 high-grade central osteosarcoma biopsies and computer-assisted whole-slide analysis was compared with conventional quantification methods including hot spot analysis. RESULTS: More than 96% of osteosarcoma samples were positive for all antigens after optimization of immunohistochemistry. In contrast, standard immunohistochemistry retrieved false negative results in 35-65% of decalcified osteosarcoma specimens. Standard hot spot analysis was applicable for homogeneous distributed FOXP3+ and CD8+ cells. However, heterogeneous distribution of vascular CD31 did not allow reliable quantification with hot spot analysis in 85% of all samples. Computer-assisted whole-slide analysis of total CD31- immunoreactive area proved as the most appropriate quantification method. CONCLUSION: Standard staining and quantification procedures are not applicable in decalcified formalin-fixed and paraffin-embedded samples for major parameters of the immunovascular microenvironment in osteosarcoma. Whole-slide imaging and optimized antigen retrieval overcome these limitations

    Upstream waves and field line resonances: simultaneous presence and alternation in Pc3 pulsation events

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    Based on a detailed study of Pc3 events at an array between L = 1.5 and 3 in Central Europe, the authors found quick changes between upstream waves (UW, i.e. pulsation directly driven by UW) and field line resonance (FLR, i.e. azimuthal oscillations of geomagnetic field lines). The alternation of the two types is especially characteristic (and the UW part stronger) if the interplanetary magnetic field (IMF) is highly variable. Events due to field line resonance may have a structure consisting of multiple lines with frequencies differing by about 10%, corresponding to neighbouring shells of field lines separated by about 100 km at the surface. This coincides with previous findings (about 10% at a meridional distance of 80 km). The frequency of the UW type is well correlated with the frequency of waves in the interplanetary medium. Additionally, there are signals of unidentified origin which also seem to be influenced by IMF.>Key words. Magnetosphere Physics · MHD waves and instabilities · Plasmasphere · Solar wind/magnetosphere interaction

    Efeito da mitomicina C tópica na cicatrização de prega vocal em modelo suíno Topical mitomycin C effect on swine vocal folds healing

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    VĂĄrias terapias adjuvantes Ă  cirurgia vĂȘm sendo usadas para modular o processo cicatricial nas pregas vocais, entre elas a Mitomicina tĂłpica (MTC). OBJETIVOS: Avaliar os efeitos da MTC no processo de cicatrização de pregas vocais de suĂ­nos 30 dias apĂłs exĂ©rese de fragmento de mucosa com laser de CO2 mediante a mensuração da deposição de colĂĄgeno. FORMA DE ESTUDO: Experimental em suĂ­nos. MATERIAIS E MÉTODOS: Dois grupos de 6 suĂ­nos cada foram avaliados apĂłs exĂ©rese de fragmento de mucosa de prega vocal a laser de CO2 (grupo controle sem uso e grupo experimento com uso de MTC tĂłpica). ApĂłs 30 dias os animais foram submetidos Ă  eutanĂĄsia, sendo coletadas amostras das pregas vocais para anĂĄlise histolĂłgica, a fim de quantificar a deposição de colĂĄgeno mediante coloração de Picrosirius Red. RESULTADOS: A mĂ©dia da ĂĄrea do colĂĄgeno total das pregas vocais do grupo controle foi de 2648,03 ”m2, enquanto a mĂ©dia do colĂĄgeno total das pregas vocais do grupo experimento foi de 2200,30 ”m2 (p = 0,0043). CONCLUSÃO: A MTC usada topicamente apĂłs a exĂ©rese de fragmento de mucosa da prega vocal a laser de CO2 em suĂ­nos, diminui, significativamente, a deposição do colĂĄgeno total.<br>several adjuvant therapies to surgery have been used to modulate the healing process of vocal folds, including topic mitomycin (MTC). AIM: to evaluate the effect of topical MTC in the healing process of vocal folds 30 days after the exeresis of a mucosal fragment with CO2 laser in a swine model (control group without mitomycin and study group with topical MTC), with collagen deposition measurement. STUDY TYPE: prospective experimental in swine. METHODS: two groups of 6 swine each were subjected to exeresis of a mucosal fragment of the vocal fold with CO2 laser. Immediately after the procedure MTC was applied topically for three minutes on the study group. Thirty days later the animals were slaughtered and samples of the vocal folds were collected for histological analysis, with the purpose of quantifying collagen deposition by Picrosirius Red stain. RESULTS: the average area of total collagen in the vocal folds in the control group was 2.648,03 ”m2, whereas in the study group it was 2.200,30 ”m2 (p = 0.0043). CONCLUSION: topical application of MTC after the exeresis of a mucous fragment of vocal fold with CO2 laser in swine significantly decreased total collagen deposition

    Improved Survival in Osteosarcoma Patients with Atypical Low Vascularization.

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    BACKGROUND: Osteosarcoma is considered a highly vascularized bone tumor with early metastatic dissemination through intratumoral blood vessels mostly into the lung. Novel targets for therapy such as tumor vascularization are highly warranted since little progress has been achieved in the last 30 years. However, proof of relevance for vascularization as a major prognostic parameter has been hampered by tumor heterogeneity, difficulty in detecting microvessels by immunohistochemistry, and small study cohorts. Most recently, we demonstrated that highly standardized whole-slide imaging could overcome these limitations (Kunz et al., PloS One 9(3):e90727, 2014). In this study, we applied this method to a multicenter cohort of 131 osteosarcoma patients to test osteosarcoma vascularization as a prognostic determinant. METHODS: Computer-assisted whole-slide analysis, together with enzymatic epitope retrieval, was used for CD31-based microvessel quantification in 131 pretreatment formalin-fixed and paraffin-embedded biopsies from three bone tumor centers. Kaplan-Meier-estimated survival and chemoresponse were determined and multivariate analysis was performed. Conventional hot-spot-based microvessel density (MVD) determination was compared with whole-slide imaging. RESULTS: We detected high estimated overall (p </= 0.008) and relapse-free (p </= 0.004) survival in 25 % of osteosarcoma patients with low osteosarcoma vascularization in contrast to other patient groups. Furthermore, all patients with low osteosarcoma vascularization showed a good response to neoadjuvant chemotherapy. Comparison of conventional MVD determination with whole-slide imaging suggests false high quantification or even exclusion of samples with low osteosarcoma vascularization due to difficult CD31 detection in previous studies. CONCLUSION: Low intratumoral vascularization at the time of diagnosis is a strong predictor for prolonged survival and good response to neoadjuvant chemotherapy in osteosarcoma

    Minimally invasive versus conventional exposure for total hip arthroplasty: a systematic review and meta-analysis of clinical and radiological outcomes

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    Over the past decade, minimally invasive surgery has gained popularity as a means of optimising early postoperative rehabilitation and increasing patient satisfaction and cosmesis following total hip arthroplasty (THA). However, this surgical exposure has also been associated with increased risk of iatrogenic nerve injury and implant mal-positioning due to limited visibility compared to conventionally larger surgical incisions. The purpose of this meta-analysis was to compare the outcomes of these two surgical exposures. A systematic review of the published and unpublished literature was conducted to include all randomised and non-randomised controlled trials comparing the clinical and radiological outcomes of minimally invasive and conventional THA procedures. In total, 28 studies met the eligibility criteria and included 2,849 hips, i.e. 1,428 minimally invasive compared to 1,421 conventional THAs. The meta-analysis of the current evidence base showed that minimally invasive THA is associated with a significantly increased risk of transient lateral femoral cutaneous nerve palsy (p = 0.006) with no significantly better outcome
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