57 research outputs found

    Predictive factors for severe toxicity of sunitinib in unselected patients with advanced renal cell cancer

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    Sunitinib has been registered for the treatment of advanced renal cell cancer (RCC). As patient inclusion was highly selective in previous studies, experience with sunitinib in general oncological practice remains to be reported. We determined the efficacy and safety of sunitinib in patients with advanced RCC included in an expanded access programme. ECOG performance status >1, histology other than clear cell and presence of brain metastases were no exclusion criteria. Eighty-two patients were treated: 23% reached a partial response, 50% had stable disease, 20% progressed and six patients were not evaluable. Median progression-free survival (PFS) was 9 months and median overall survival (OS) was 15 months. Importantly, 47 patients (57%) needed a dose reduction, 35 (43%) because of treatment-related adverse events, 10 (12%) because of continuous dosing, and two because of both. Stomatitis, fatigue, hand–foot syndrome and a combination of grade 1–2 adverse events were the most frequent reasons for dose reduction. In 40 patients (49%), there was severe toxicity, defined as dose reduction or permanent discontinuation, which was highly correlated with low body surface area, high age and female gender. On the basis of age and gender, a model was developed that could predict the probability of severe toxicity

    Paclitaxel in self-micro emulsifying formulations: oral bioavailability study in mice

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    The anticancer drug paclitaxel is formulated for i.v. administration in a mixture of Cremophor EL and ethanol. Its oral bioavailability is very low due to the action of P-glycoprotein in the gut wall and CYP450 in gut wall and liver. However, proof-of-concept studies using the i.v. formulation diluted in drinking water have demonstrated the feasibility of the oral route as an alternative when given in combination with inhibitors of P-glycoprotein and CYP450. Because of the unacceptable pharmaceutical properties of the drinking solution, a better formulation for oral application is needed. We have evaluated the suitability of various self-micro emulsifying oily formulations (SMEOF’s) of paclitaxel for oral application using wild-type and P-glycoprotein knockout mice and cyclosporin A (CsA) as P-glycoprotein and CYP450 inhibitor. The oral bioavailability of paclitaxel in all SMEOF’s without concomitant CsA was low in wild-type mice, showing that this vehicle does not enhance intestinal uptake by itself. Paclitaxel (10 mg/kg) in SMEOF#3 given with CsA resulted in plasma levels that were comparable to the Cremophor EL-ethanol containing drinking solution plus CsA. Whereas the AUC increased linearly with the oral paclitaxel dose in P-glycoprotein knockout mice, it increased less than proportional in wild-type mice given with CsA. In both strains more unchanged paclitaxel was recovered in the feces at higher doses. This observation most likely reflects more profound precipitation of paclitaxel within the gastro-intestinal tract at higher doses. The resulting absolute reduction in absorption of paclitaxel from the gut was possibly concealed by partial saturation of first-pass metabolism when P-glycoprotein was absent. In conclusion, SMEOF’s maybe a useful vehicle for oral delivery of paclitaxel in combination with CsA, although the physical stability within the gastro-intestinal tract remains a critical issue, especially when applied at higher dose levels

    Extracerebral metastases determine the outcome of patients with brain metastases from renal cell carcinoma

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    <p>Abstract</p> <p>Background</p> <p>In the era of cytokines, patients with brain metastases (BM) from renal cell carcinoma had a significantly shorter survival than patients without. Targeted agents (TA) have improved the outcome of patients with metastatic renal cell carcinoma (mRCC) however, their impact on patients with BM is less clear. The aim of this analysis was to compare the outcome of patients with and without BM in the era of targeted agents.</p> <p>Methods</p> <p>Data from 114 consecutive patients who had access to targeted agent were analyzed for response rates (ORR), progression free survival (PFS) and overall survival (OS). All patients diagnosed with BM underwent local, BM-specific treatment before initiation of medical treatment.</p> <p>Results</p> <p>Data of 114 consecutive patients who had access to at least one type of targeted agents were analyzed. Twelve out of 114 renal cell carcinoma (RCC) patients (10.5%) were diagnosed with BM. Systemic treatment consisted of sunitinib, sorafenib, temsirolimus or bevacizumab. The median PFS was 8.7 months (95% CI 5.1 - 12.3) and 11.4 months (95% CI 8.7 - 14.1) for BM-patients and non-BM-patients, respectively (p = 0.232). The median overall survival for patients with and without BM was 13.4 (95% CI 1- 43.9) and 33.3 months (95% CI 18.6 - 47.0) (p = 0.358), respectively. No patient died from cerebral disease progression. ECOG Performance status and the time from primary tumor to metastases (TDM) were independent risk factors for short survival (HR 2.74, p = 0.001; HR: 0.552, p = 0.034).</p> <p>Conclusions</p> <p>Although extracerebral metastases determine the outcome of patients with BM, the benefit from targeted agents still appears to be limited when compared to patients without BM.</p

    Specific bottom–up effects of arbuscular mycorrhizal fungi across a plant–herbivore–parasitoid system

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    The majority of plants are involved in symbioses with arbuscular mycorrhizal fungi (AMF), and these associations are known to have a strong influence on the performance of both plants and insect herbivores. Little is known about the impact of AMF on complex trophic chains, although such effects are conceivable. In a greenhouse study we examined the effects of two AMF species, Glomus intraradices and G. mosseae on trophic interactions between the grass Phleum pratense, the aphid Rhopalosiphum padi, and the parasitic wasp Aphidius rhopalosiphi. Inoculation with AMF in our study system generally enhanced plant biomass (+5.2%) and decreased aphid population growth (−47%), but there were no fungal species-specific effects. When plants were infested with G. intraradices, the rate of parasitism in aphids increased by 140% relative to the G. mosseae and control treatment. When plants were associated with AMF, the developmental time of the parasitoids decreased by 4.3% and weight at eclosion increased by 23.8%. There were no clear effects of AMF on the concentration of nitrogen and phosphorus in plant foliage. Our study demonstrates that the effects of AMF go beyond a simple amelioration of the plants’ nutritional status and involve rather more complex species-specific cascading effects of AMF in the food chain that have a strong impact not only on the performance of plants but also on higher trophic levels, such as herbivores and parasitoids

    Putting prevention into practice: qualitative study of factors that inhibit and promote preventive care by general practitioners, with a focus on elderly patients

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    <p>Abstract</p> <p>Background</p> <p>General practitioners (GPs) have a key role in providing preventive care, particularly for elderly patients. However, various factors can inhibit or promote the implementation of preventive care. In the present study, we identified and examined factors that inhibit and promote preventive care by German GPs, particularly for elderly patients, and assessed changes in physicians' attitudes toward preventive care throughout their careers.</p> <p>Methods</p> <p>A qualitative, explorative design was used to identify inhibitors and promoters of preventive care in German general medical practice. A total of 32 GPs in Berlin and Hannover were surveyed. Questions about factors that promote or inhibit implementation of preventive care and changes in physicians' perceptions of promoting and inhibiting factors throughout their careers were identified. Episodic interviews, which encouraged the reporting of anecdotes regarding daily knowledge and experiences, were analyzed using ATLAS/ti. Socio-demographic data of GPs and structural information about their offices were collected using short questionnaires. The factors identified as inhibitory or promoting were classified as being related to patients, physicians, or the healthcare system. The changes in GP attitudes toward preventive care throughout their careers were classified as personal transitions or as social and health policy transitions.</p> <p>Results</p> <p>Most of the identified barriers to preventive care were related to patients, such as a lack of motivation for making lifestyle changes and a lack of willingness to pay for preventive interventions. In addition, the healthcare system seemed to inadequately promote preventive care, mainly due to poor reimbursement for preventive care and fragmentation of care. GPs own attitudes and health habits seemed to influence the implementation of preventive care. GPs recognized their own lack of awareness of effective preventive interventions, particularly for elderly patients. GPs were motivated by positive preventive experiences, but often lacked the necessary training to counsel and support their patients.</p> <p>Conclusions</p> <p>German GPs had positive attitudes towards prevention, but the implementation of preventive care was neither systematic nor continuous. Identification and elimination of barriers to preventive care is crucial. Further research is needed to identify effective practice-based approaches to overcome these barriers.</p

    Patient-specific finite element estimated femur strength as a predictor of the risk of hip fracture: the effect of methodological determinants

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    Summary: A finite element modelling pipeline was adopted to predict femur strength in a retrospective cohort of 100 women. The effects of the imaging protocol and the meshing technique on the ability of the femur strength to classify the fracture and the control groups were analysed. Introduction: The clinical standard to estimate the risk of osteoporotic hip fracture is based on the areal bone mineral density (aBMD). A few retrospective studies have concluded that finite element (FE)-based femoral strength is a better classifier of fracture and control groups than the aBMD, while others could not find significant differences. We investigated the effect of the imaging protocol and of the FE modelling techniques on the discriminatory power of femoral strength. Methods: A retrospective cohort of 100 post-menopausal women (50 with hip fracture, 50 controls) was examined. Each subject received a dual-energy absorptiometry (DXA) exam and a computed tomography (CT) scan of the proximal femur region. Each case was modelled a number of times, using different modelling pipelines, and the results were compared in terms of accuracy in discriminating the fracture and the control cases. The baseline pipeline involved local anatomical orientation and mesh morphing. Revised pipelines involved global anatomical orientation using a full-femur atlas registration and an optimised meshing algorithm. Minimum physiological (MPhyS) and pathological (MPatS) strengths were estimated for each subject. Area under the receiver operating characteristic (ROC) curve (AUC) was calculated to compare the ability of MPhyS, MPatS and aBMD to classify the control and the cases. Results: Differences in the modelling protocol were found to considerably affect the accuracy of the FE predictors. For the most optimised protocol, logistic regression showed aBMD Neck , MPhyS and MPatS to be significantly associated with the facture status, with AUC of 0.75, 0.75 and 0.79, respectively. Conclusion: The study emphasized the necessity of modelling the whole femur anatomy to develop a robust FE-based tool for hip fracture risk assessment. FE-strength performed only slightly better than the aBMD in discriminating the fracture and control cases. Differences between the published studies can be explained in terms of differences in the modelling protocol and cohort design

    Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

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    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

    A multiscale model to predict current absolute risk of femoral fracture in a postmenopausal population

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    Osteoporotic hip fractures are a major healthcare problem. Fall severity and bone strength are important risk factors of hip fracture. This study aims to obtain a mechanistic explanation for fracture risk in dependence of these risk factors. A novel modelling approach is developed that combines models at different scales to overcome the challenge of a large space–time domain of interest and considers the variability of impact forces between potential falls in a subject. The multiscale model and its component models are verified with respect to numerical approximations made therein, the propagation of measurement uncertainties of model inputs is quantified, and model predictions are validated against experimental and clinical data. The main results are model predicted absolute risk of current fracture (ARF0) that ranged from 1.93 to 81.6% (median 36.1%) for subjects in a retrospective cohort of 98 postmenopausal British women (49 fracture cases and 49 controls); ARF0 was computed up to a precision of 1.92 percentage points (pp) due to numerical approximations made in the model; ARF0 possessed an uncertainty of 4.00 pp due to uncertainties in measuring model inputs; ARF0 classified observed fracture status in the above cohort with AUC = 0.852 (95% CI 0.753–0.918), 77.6% specificity (95% CI 63.4–86.5%) and 81.6% sensitivity (95% CI 68.3–91.1%). These results demonstrate that ARF0 can be computed using the model with sufficient precision to distinguish between subjects and that the novel mechanism of fracture risk determination based on fall dynamics, hip impact and bone strength can be considered validated
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