38 research outputs found

    Zeniplatin in patients with advanced ovarian cancer, a phase II study with a third generation platinum complex

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    25 patients with residual or recurrent ovarian cancer were treated with the new platinum complex zeniplatin (CL 286,558) and 23 patients were evaluable for response. Responses were achieved in 4 patients, 1 complete and 3 partial remissions (16%). 7 patients had stable disease and 12 patients had tumour progression. At a median follow-up of 12 months, the median progression-free survival in responding patients was 11 months and overall survival 81%. The median overall survival of progressive patients amounted to 9 months, indicating the advanced stage of disease in most patients. Renal function was monitored by isotope clearance studies. There was no significant change in effective renal plasma flow (ERPF) or glomerular filtration rate (GFR) in 10 patients who completed six cycles of treatment. 1 patient with a marginal creatinine clearance at baseline suffered from sudden and severe renal failure during the first cycle. Zeniplatin may be active in relapsing, platinum-pretreated patients, and has no direct effects on renal function as measured by isotope clearance. Despite these findings, occasional nephrotoxicity may occur in patients with compromised kidney function, even with prophylactic hydration, and thus limit the application of this new analogue

    The effect of propofol on effective brain networks

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    Objective: We compared the effective networks derived from Single Pulse Electrical Stimulation (SPES) in intracranial electrocorticography (ECoG) of awake epilepsy patients and while under general propofol-anesthesia to investigate the effect of propofol on these brain networks. Methods: We included nine patients who underwent ECoG for epilepsy surgery evaluation. We performed SPES when the patient was awake (SPES-clinical) and repeated this under propofol-anesthesia during the surgery in which the ECoG grids were removed (SPES-propofol). We detected the cortico-cortical evoked potentials (CCEPs) with an automatic detector. We constructed two effective networks derived from SPES-clinical and SPES-propofol. We compared three network measures (indegree, outdegree and betweenness centrality), the N1-peak-latency and amplitude of CCEPs between the two effective networks. Results: Fewer CCEPs were observed during SPES-propofol (median: 6.0, range: 0–29) compared to SPES-clinical (median: 10.0, range: 0–36). We found a significant correlation for the indegree, outdegree and betweenness centrality between SPES-clinical and SPES-propofol (respectively rs = 0.77, rs = 0.70, rs = 0.55, p < 0.001). The median N1-peak-latency increased from 22.0 ms during SPES-clinical to 26.4 ms during SPES-propofol. Conclusions: Our findings suggest that the number of effective network connections decreases, but network measures are only marginally affected. Significance: The primary network topology is preserved under propofol

    Total 18F-dopa PET tumour uptake reflects metabolic endocrine tumour activity in patients with a carcinoid tumour

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    Positron emission tomography (PET) using 6-[(18)F]fluoro-L-dihydroxyphenylalanine ((18)F-dopa) has an excellent sensitivity to detect carcinoid tumour lesions. (18)F-dopa tumour uptake and the levels of biochemical tumour markers are mediated by tumour endocrine metabolic activity. We evaluated whether total (18)F-dopa tumour uptake on PET, defined as whole-body metabolic tumour burden (WBMTB), reflects tumour load per patient, as measured with tumour markers. Seventy-seven consecutive carcinoid patients who underwent an (18)F-dopa PET scan in two previously published studies were analysed. For all tumour lesions mean standardised uptake values (SUVs) at 40% of the maximal SUV and tumour volume on (18)F-dopa PET were determined and multiplied to calculate a metabolic burden per lesion. WBMTB was the sum of the metabolic burden of all individual lesions per patient. The 24-h urinary serotonin, urine and plasma 5-hydroxindoleacetic acid (5-HIAA), catecholamines (nor)epinephrine, dopamine and their metabolites, measured in urine and plasma, and serum chromogranin A served as tumour markers. All but 1 were evaluable for WBMTB; 74 patients had metastatic disease. (18)F-dopa PET detected 979 lesions. SUV(max) on (18)F-dopa PET varied up to 29-fold between individual lesions within the same patients. WBMTB correlated with urinary serotonin (r = 0.51) and urinary and plasma 5-HIAA (r = 0.78 and 0.66). WBMTB also correlated with urinary norepinephrine, epinephrine, dopamine and plasma dopamine, but not with serum chromogranin A. Tumour load per patient measured with (18)F-dopa PET correlates with tumour markers of the serotonin and catecholamine pathway in urine and plasma in carcinoid patients, reflecting metabolic tumour activity

    Re-emergence of enterovirus D68 in Europe after easing the COVID-19 lockdown, September 2021

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    We report a rapid increase in enterovirus D68 (EV-D68) infections, with 139 cases reported from eight European countries between 31 July and 14 October 2021. This upsurge is in line with the seasonality of EV-D68 and was presumably stimulated by the widespread reopening after COVID-19 lockdown. Most cases were identified in September, but more are to be expected in the coming months. Reinforcement of clinical awareness, diagnostic capacities and surveillance of EV-D68 is urgently needed in Europe.Peer Reviewe

    Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

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    We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

    Generalized Hénon map and bifurcations of homoclinic tangencies

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    We study two-parameter bifurcation diagrams of a generalized Hénon map (GHM) that is known to describe dynamics of iterated maps near homoclinic and heteroclinic tangencies. We prove the nondegeneracy of codimension (codim) 2 bifurcations of fixed points of the GHM analytically and compute its various global and local bifurcation curves numerically. Special attention is given to the interpretation of the results and their application to the analysis of bifurcations of the homoclinic tangency of a neutral saddle in two-parameter families of planar diffeomorphisms. In particular, an infinite cascade of homoclinic tangencies of neutral saddle cycles is shown to exist near the homoclinic tangency of the primary neutral saddle

    Modal interaction in a levitation force MEMS based resonator

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    This work aims to examine the possibility of internal resonances (modal interactions) among the vibration modes of a levitation force Micro-electro-mechanical Systems (MEMS) based resonator. The actuating levitation force is generated through a special arrangement consisting of two stationary side electrodes (both electrically charged) and a middle grounded unit consisting of the stationary electrode located beneath a moving electrode (micro-beam). Both “cantilever” (CL) and “clamped-clamped” (CC) microbeams are analysed as the moving element of this especial design in which the applied voltage pushes away the micro beam from the underneath substrate. All possible commensurable relations between the frequencies are inspected. We use the numerical bifurcation toolbox MatCont to capture the computed frequency response branches and examine their stability. A period-doubling bifurcation for the possible onset of chaotic attractors is inspected as well. A preliminary eigenvalue problem analysis suggests the internal resonance may exist in both (CC and CL) cases. However, an extended dynamical analysis shows that just a 3-to-1 modal interaction (between the first and third modes) in the CC arrangement is possible. The effects of dominant force-related terms are plotted through associated plots. These diagrams demonstrated that this design exhibits a rich internal resonance behavior that can be controlled with different geometrical and actuating parameters. Overall, this effort provides a systematic methodology and simple guidelines for in-depth exploration of internal resonances in levitation force-based microbeams. The outcomes of this work could also assist in the development of MEMS sensors based on the internal resonance phenomenon

    Factor VIII C1 domain residues Lys 2092 and Phe 2093 contribute to membrane binding and cofactor activity

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    Binding of factor VIII to membranes containing phosphatidyl-L-serine (Ptd-L-Ser) is mediated, in part, by a motif localized to the C2 domain. We evaluated a putative membrane-binding role of the C1 domain using an anti-C1 antibody fragment, KM33(scFv), and factor VIII mutants with an altered KM33 epitope. We prepared a dual mutant Lys2092/Phe2093 -> Ala/Ala (fVIII(YFP) (2092/93)) and 2 single mutants Lys2092 -> Ala and Phe2093 -> Ala. KM33(scFv) inhibited binding of fluorescein-labeled factor VIII to synthetic membranes and inhibited at least 95% of factor Xase activity. fVIII(YFP 2092/93) had 3-fold lower affinity for membranes containing 15% Ptd-L-Ser but more than 10-fold reduction in affinity for membranes with 4% Ptd-L-Ser. In a microtiter plate, KM33(scFv) was additive with an anti-C2 antibody for blocking binding to vesicles of 15% Ptd-L-Ser, whereas either antibody blocked binding to vesicles of 4% Ptd-L-Ser. KM33(scFv) inhibited binding to platelets and fVIII(YFP 2092/93) had reduced binding to A23187-stimulated platelets. fVIII(YFP 2092) exhibited normal activity at various Ptd-L-Ser concentrations, whereas fVIII(YFP 2093) showed a reduction of activity with Ptd-L-Ser less than 12%. fVIII(YFP 2092/93) had a greater reduction of activity than either single mutant. These results indicate that Lys 2092 and Phe 2093 are elements of a membrane-binding motif on the factor VIII C1 domain. (Blood. 2009;114:3938-3946

    Tracking of nociceptive thresholds using adaptive psychophysical methods

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    Psychophysical thresholds reflect the state of the underlying nociceptive mechanisms. For example, noxious events can activate endogenous analgesic mechanisms that increase the nociceptive threshold. Therefore, tracking thresholds over time facilitates the investigation of the dynamics of these underlying mechanisms. Threshold tracking techniques should use efficient methods for stimulus selection and threshold estimation. This study compares, in simulation and in human psychophysical experiments, the performance of different combinations of adaptive stimulus selection procedures and threshold estimation methods. Monte Carlo simulations were first performed to compare the bias and precision of threshold estimates produced by three different stimulus selection procedures (simple staircase, random staircase, and minimum entropy procedure) and two estimation methods (logistic regression and Bayesian estimation). Logistic regression and Bayesian estimations resulted in similar precision only when the prior probability distributions (PDs) were chosen appropriately. The minimum entropy and simple staircase procedures achieved the highest precision, while the random staircase procedure was the least sensitive to different procedure-specific settings. Next, the simple staircase and random staircase procedures, in combination with logistic regression, were compared in a human subject study (n = 30). Electrocutaneous stimulation was used to track the nociceptive perception threshold before, during, and after a cold pressor task, which served as the conditioning stimulus. With both procedures, habituation was detected, as well as changes induced by the conditioning stimulus. However, the random staircase procedure achieved a higher precision. We recommend using the random staircase over the simple staircase procedure, in combination with logistic regression, for nonstationary threshold tracking experiments
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