336 research outputs found
Chaos en orde in de wereldlandbouw
Gebrek aan elasticiteit, solidariteit en autoriteit / door P.C. van den Noort ; Internationale arbeidsverdeling en marktorde / door J. de Hoogh ; Redes 6-12-1979 Wageninge
Comparative Genomics of Peroxisome Biogenesis Proteins:Making Sense of the PEX Proteins
PEX genes encode proteins involved in peroxisome biogenesis and proliferation. Using a comparative genomics approach, we clarify the evolutionary relationships between the 37 known PEX proteins in a representative set of eukaryotes, including all common model organisms, pathogenic unicellular eukaryotes and human. A large number of previously unknown PEX orthologs were identified. We analyzed all PEX proteins, their conservation and domain architecture and defined the core set of PEX proteins that is required to make a peroxisome. The molecular processes in peroxisome biogenesis in different organisms were put into context, showing that peroxisomes are not static organelles in eukaryotic evolution. Organisms that lack peroxisomes still contain a few PEX proteins, which probably play a role in alternative processes. Finally, the relationships between PEX proteins of two large families, the Pex11 and Pex23 families, were analyzed, thereby contributing to the understanding of their complicated and sometimes incorrect nomenclature. We provide an exhaustive overview of this important eukaryotic organelle
Skin marker-based versus bone morphology-based coordinate systems of the hindfoot and forefoot
Segment coordinate systems (CSs) of marker-based multi-segment foot models are used to measure foot kinematics, however their relationship to the underlying bony anatomy is barely studied. The aim of this study was to compare marker-based CSs (MCSs) with bone morphology-based CSs (BCSs) for the hindfoot and forefoot. Markers were placed on the right foot of fifteen healthy adults according to the Oxford, Rizzoli and Amsterdam Foot Model (OFM, RFM and AFM, respectively). A CT scan was made while the foot was loaded in a simulated weight-bearing device. BCSs were based on axes of inertia. The orientation difference between BCSs and MCSs was quantified in helical and 3D Euler angles. To determine whether the marker models were able to capture inter-subject variability in bone poses, linear regressions were performed. Compared to the hindfoot BCS, all MCSs were more toward plantar flexion and internal rotation, and RFM was also oriented toward more inversion. Compared to the forefoot BCS, OFM and RFM were oriented more toward dorsal and plantar flexion, respectively, and internal rotation, while AFM was not statistically different in the sagittal and transverse plane. In the frontal plane, OFM was more toward eversion and RFM and AFM more toward inversion compared to BCS. Inter-subject bone pose variability was captured with RFM and AFM in most planes of the hindfoot and forefoot, while this variability was not captured by OFM. When interpreting multi-segment foot model data it is important to realize that MCSs and BCSs do not always align.</p
Stereoselective Protection-Free Modification of 3-Keto-saccharides
Unprotected 3-keto-saccharides have become readily accessible via site-selective oxidation, but their protection-free functionalization is relatively unexplored. Here we show that protecting groups are obsolete in a variety of stereoselective modifications of our model substrate methyl α-glucopyranoside. This allows the preparation of rare sugars and the installation of click handles and reactive groups. To showcase the applicability of the methodology, maltoheptaose has been converted into a chemical probe, and the rare sugar evalose has been synthesized
New mechanisms to explain the effects of added lactose fines on the dispersion performance of adhesive mixtures for inhalation
Fine excipient particles or 'fines' have been shown to improve the dispersion performance of carrier-based formulations for dry powder inhalation. Mechanistic formulation studies have focussed mainly on explaining this positive effect. Previous studies have shown that higher drug contents may cause a decrease in dispersion performance, and there is no reason why this should not be true for fines with a similar shape, size and cohesiveness as drug particles. Therefore, the effects on drug detachment of 'fine lactose fines' (FLF, X50 = 1.95 µm) with a similar size and shape as micronised budesonide were studied and compared to those of 'coarse lactose fines' (CLF, X50 = 3.94 µm). Furthermore, interactions with the inhalation flow rate, the drug content and the mixing order were taken into account. The observed effects of FLF are comparable to drug content effects in that the detached drug fraction was decreased at low drug content and low flow rates but increased at higher flow rates. At high drug content the effects of added FLF were negligible. In contrast, CLF resulted in higher detached drug fractions at all flow rates and drug contents. The results from this study suggest that the effects of fines may be explained by two new mechanisms in addition to those previously proposed. Firstly, fines below a certain size may increase the effectiveness of press-on forces or cause the formation of strongly coherent fine particle networks on the carrier surface containing the drug particles. Secondly, when coarse enough, fines may prevent the formation of, or disrupt such fine particle networks, possibly through a lowering of their tensile strength. It is recommended that future mechanistic studies are based on the recognition that added fines may have any effect on dispersion performance, which is determined by the formulation and dispersion conditions
Randomised controlled trial of first-line tyrosine-kinase inhibitor (TKI) versus intercalated TKI with chemotherapy for EGFR-mutated nonsmall cell lung cancer
Introduction Previous studies have shown interference between epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors and chemotherapy in the cell cycle, thus reducing efficacy. In this randomised controlled trial we investigated whether intercalated erlotinib with chemotherapy was superior compared to erlotinib alone in untreated advanced EGFR-mutated nonsmall cell lung cancer (NSCLC). Materials and methods Treatment-naïve patients with an activating EGFR mutation, ECOG performance score of 0–3 and adequate organ function were randomly assigned 1:1 to either four cycles of cisplatin-pemetrexed with intercalated erlotinib (day 2–16 out of 21 days per cycle) followed by pemetrexed and erlotinib maintenance (CPE) or erlotinib monotherapy. The primary end-point was progression-free survival (PFS). Secondary end-points were overall survival, objective response rate (ORR) and toxicity. Results Between April 2014 and September 2016, 22 patients were randomised equally into both arms; the study was stopped due to slow accrual. Median follow-up was 64 months. Median PFS was 13.7 months (95% CI 5.2–18.8) for CPE and 10.3 months (95% CI 7.1–15.5; hazard ratio (HR) 0.62, 95% CI 0.25–1.57) for erlotinib monotherapy; when compensating for number of days receiving erlotinib, PFS of the CPE arm was superior (HR 0.24, 95% CI 0.07–0.83; p=0.02). ORR was 64% for CPE versus 55% for erlotinib monotherapy. Median overall survival was 31.7 months (95% CI 21.8–61.9 months) for CPE compared to 17.2 months (95% CI 11.5–45.5 months) for erlotinib monotherapy (HR 0.58, 95% CI 0.22–1.41 months). Patients treated with CPE had higher rates of treatment-related fatigue, anorexia, weight loss and renal toxicity. Conclusion Intercalating erlotinib with cisplatin-pemetrexed provides a longer PFS compared to erlotinib alone in EGFR-mutated NSCLC at the expense of more toxicity
Switch-maintenance gemcitabine after first-line chemotherapy in patients with malignant mesothelioma (NVALT19):an investigator-initiated, randomised, open-label, phase 2 trial
Background Almost all patients with malignant mesothelioma eventually have disease progression after first-line therapy. Previous studies have investigated maintenance therapy, but none has shown a great effect. We aimed to assess the efficacy and safety of switch-maintenance gemcitabine in patients with malignant mesothelioma without disease progression after first-line chemotherapy. Methods We did a randomised, open-label, phase 2 trial in 18 hospitals in the Netherlands (NVALT19). We recruited patients aged older than 18 years with unresectable malignant mesothelioma with no evidence of disease progression after at least four cycles of first-line chemotherapy (with platinum and pemetrexed), who had a WHO performance status of 0-2, adequate organ function, and measurable or evaluable disease. Exclusion criteria were active uncontrolled infection or severe cardiac dysfunction, serious disabling conditions, symptomatic CNS metastases, radiotherapy within 2 weeks before enrolment, and concomitant use of any other drugs under investigation. Patients were randomly assigned (1:1), using the minimisation method, to maintenance intravenous gemcitabine (1250 mg/m(2) on days 1 and 8, in cycles of 21 days) plus supportive care, or to best supportive care alone, until disease progression, unacceptable toxicity, serious intercurrent illness, patient request for discontinuation, or need for any other anticancer agent, except for palliative radiotherapy. A CT scan of the thorax or abdomen (or both) and pulmonary function tests were done at baseline and repeated every 6 weeks. The primary outcome was progression-free survival in the intention-to-treat population. Safety was analysed in all participants who received one or more doses of the study drug or had at least one visit for supportive care. Recruitment is now closed; treatment and follow-up are ongoing. This study is registered with the Netherlands Trial Registry, NTR4132/NL3847. Findings Between March 20, 2014, and Feb 27, 2019, 130 patients were enrolled and randomly assigned to gemcitabine plus supportive care (65 patients [50%]) or supportive care alone (65 patients [50%]). No patients were lost to follow-up; median follow-up was 36.5 months (95% CI 34.2 to not reached), and one patient in the supportive care group withdrew consent. Progression-free survival was significantly longer in the gemcitabine group (median 6.2 months [95% CI 4.6-8.7]) than in the supportive care group (3.2 months [2.8-4.1]; hazard ratio [HR] 0.48 [95% CI 0.33-0.71]; p=0.0002). The benefit was confirmed by masked independent central review (HR 0.49 [0.33-0.72]; p=0.0002). Grade 3-4 adverse events occurred in 33 ( 52%) of 64 patients in the gemcitabine group and in ten (16%) of 62 patients in the supportive care group. The most frequent adverse events were anaemia, neutropenia, fatigue or asthenia, pain, and infection in the gemcitabine group, and pain, infection, and cough or dyspnoea in the supportive care group. One patient (2%) in the gemcitabine group died, due to a treatment-related infection. Interpretation Switch-maintenance gemcitabine, after first-line chemotherapy, significantly prolonged progression-free survival compared with best supportive care alone, among patients with malignant mesothelioma. This study confirms the activity of gemcitabine in treating malignant mesothelioma
Ninety-day complication rate based on 532 Latarjet procedures in Dutch hospitals with different operation volumes
Background: In this study, we aimed to provide insight into the 90-day complication rates following the Latarjet procedure. Data from 2015 were collected from multiple hospitals in the Netherlands, with different volumes of Latarjet procedures. Our second aim was to examine which patient and surgical factors were associated with complications.Methods: We conducted a retrospective chart review of 13 hospitals between 2015 and 2022. Data regarding complications within 90 days of Latarjet procedures were extracted. The effect of sex, age, body mass index (BMI), smoking, previous shoulder operations, fixation material, hospital volume, screw size, and operation time on the complication rate was assessed by multivariable logistic regression analysis.Results: Of the 532 included patients, 58 (10.9%) had complications. The most common complications were material failure (n = 19, 3.6%) and nerve injury (n = 13, 2.4%). The risk of complications was lower for male patients than for female patients (odds ratio, 0.40; 95% confidence interval, 0.21-0.77; P = .006). Age, BMI, smoking, previous shoulder operations, type of fixation material, hospital volume, screw size, and operation time were not associated with complications.Conclusion: The 90-day complication rate after the Latarjet procedure was 10.9% and was higher in female patients than in male patients. Age, BMI, smoking, previous shoulder operations, type of fixation material, hospital volume, screw size, and operation time did not affect complication rates. We advise setting up a national registry to prevent under-reporting of complications.</p
Lateral Trunk Motion and Knee Pain in Osteoarthritis of the Knee: a cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Patients with osteoarthritis of the knee may change their gait in an attempt to reduce loading of the affected knee, thereby reducing pain. Especially changes in lateral trunk motion may be potentially effective, since these will affect the position of the centre of mass relative to the knee, enabling minimization of the load on the knee and thereby knee pain. The aim of the study was to test the hypothesis that a higher level of knee pain is associated with higher lateral trunk motion in patients with knee OA.</p> <p>Methods</p> <p>Fifty-two patients with OA of the knee were tested. Lateral trunk motion was measured during the stance phase of walking with an optoelectronic motion analysis system and a force plate. Knee pain was measured with the VAS and the WOMAC pain questionnaire. Regression analyses were performed to assess the relationship between lateral trunk motion and knee pain.</p> <p>Results</p> <p>It was shown that in bivariate analyses knee pain was not associated with lateral trunk motion. In regression analyses, pain was associated with more lateral trunk motion. In addition, more lateral trunk motion was associated with younger age, being female, higher self-reported knee stiffness and higher maximum walking speed.</p> <p>Conclusion</p> <p>Pain is associated with lateral trunk motion. This association is weak and is influenced by age, gender, self-reported stiffness and maximum walking speed.</p
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