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1.
ACS Omega ; 9(39): 40378-40393, 2024 Oct 01.
Article in English | MEDLINE | ID: mdl-39372015

ABSTRACT

5-Hydroxymethylfurfural (HMF) is an attractive building block for biobased chemicals. Typically, ketoses like d-fructose (FRC) are suitable starting materials and give good yields of HMF in a simple aqueous phase process with a BroÌ·nsted acid catalyst. With aldoses, such as d-glucose (GLU), much lower yields were reported in the literature. Here, we report an experimental and modeling study on the use of d-galactose (GAL) for HMF synthesis, using a liquid-liquid system (water/MIBK) in combination with an HCl/AlCl3 catalyst. Experiments were conducted in a batch system with temperatures between 112 and 153 °C, HCl and AlCl3 concentrations ranging from 0.02 to 0.04 M, and initial GAL concentrations between 0.1 and 1.0 M. The highest HMF yield was 49 mol % obtained for a batch time of 90 min at 135 °C. This value is much higher than in experiments with GAL in a monophasic aqueous system with HCl as the catalyst (2 mol % HMF yield) under similar reaction conditions. Based on detailed product analyses, a reaction scheme is proposed in which the isomerization of GAL to tagatose (TAG), catalyzed by the Lewis acid AlCl3, is the first and key step. TAG is then converted to HMF by BroÌ·nsted acid HCl. The experimental data were modeled using a statistical approach as well as a kinetic approach. The kinetic model demonstrates a good agreement between the experimental and modeled data. Our findings reveal that temperature is the reaction variable with the most significant influence on the HMF yield. The use of a biphasic system appears to be a promising method for HMF production from GAL.

2.
JAMA Netw Open ; 7(2): e240054, 2024 Feb 05.
Article in English | MEDLINE | ID: mdl-38376841

ABSTRACT

Importance: Cause of ischemic stroke in young people is highly variable; however, the risk of recurrence is often presented with all subtypes of stroke grouped together in classification systems such as the Trial of ORG (danaparoid sodium [Orgaran]) 10172 in Acute Stroke Treatment (TOAST) criteria, which limits the ability to individually inform young patients with stroke about their risk of recurrence. Objective: To determine the short-term and long-term risk of recurrent vascular events after ischemic stroke at a young age by stroke cause and to identify factors associated with recurrence. Design, Setting, and Participants: This cohort study used data from the Observational Dutch Young Symptomatic Stroke Study, a prospective, multicenter, hospital-based cohort study, conducted at 17 hospitals in the Netherlands between 2013 and 2021. Eligible participants included 30-day survivors of an initial, neuroimaging-proven ischemic stroke (aged 18-49 years). Data analysis was conducted from June to July 2023. Exposure: Diagnosis of a first-ever, ischemic stroke via neuroimaging. Main Outcome and Measures: The primary outcome was short-term (within 6 months) and long-term (within 5 years) recurrence risk of any vascular event, defined as fatal or nonfatal recurrent ischemic stroke, transient ischemic attack, myocardial infarction, and revascularization procedure. Predefined characteristics were chosen to identify factors associated with risk of recurrence (cause of stroke, age, sex, stroke severity, and cardiovascular health factors). Results: A total of 1216 patients (median [IQR] age, 44.2 [38.4-47.7] years; 632 male [52.0%]; 584 female [48.0%]) were included, with a median (IQR) follow-up of 4.3 (2.6-6.0) years. The 6-month risk of any recurrent ischemic event was 6.7% (95% CI, 5.3%-8.1%), and the 5-year risk was 12.2% (95% CI, 10.2%-14.2%)The short-term risk was highest for patients with cervical artery dissections (13.2%; 95% CI, 7.6%-18.7%). Other factors associated with a recurrent short-term event were atherothrombotic stroke, rare causes of stroke, and hypertension. The long-term cumulative risk was highest for patients with atherothrombotic stroke (22.7%; 95% CI, 10.6%-34.7%) and lowest for patients with cryptogenic stroke (5.8%; 95% CI, 3.0%-8.5%). Cardioembolic stroke was associated with a recurrent long-term event, as were diabetes and alcohol abuse. Conclusions and Relevance: The findings of this cohort study of 1216 patients with an ischemic stroke at a young age suggest that the risk of recurrent vascular events was high and varied by cause of stroke both for short-term and long-term follow-up, including causes that remained concealed when combined into 1 category in the routinely used TOAST criteria. This knowledge will allow for more personalized counseling of young patients with stroke.


Subject(s)
Ischemic Attack, Transient , Ischemic Stroke , Stroke , Humans , Female , Male , Young Adult , Adolescent , Adult , Ischemic Stroke/epidemiology , Ischemic Stroke/etiology , Cohort Studies , Prospective Studies , Stroke/epidemiology , Stroke/etiology , Ischemic Attack, Transient/epidemiology , Ischemic Attack, Transient/etiology
3.
J Neurol Neurosurg Psychiatry ; 95(6): 571-579, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38160045

ABSTRACT

BACKGROUND: Limited data exists on cognitive recovery in young stroke patients. We aimed to investigate the longitudinal course of cognitive performance during the first year after stroke at young age and identify predictors for cognitive recovery. METHODS: We conducted a multicentre prospective cohort study between 2013 and 2021, enrolling patients aged 18-49 years with first-ever ischaemic stroke. Cognitive assessments were performed within 6 months and after 1 year following the index event, covering seven cognitive domains. Composite Z-scores using normative data determined cognitive impairment (Z-score<-1.5). A Reliable Change Index (RCI) assessed cognitive recovery (RCI>1.96) or decline (RCI<-1.96). RESULTS: 393 patients (median age 44.3 years, IQR 38.4-47.2) completed cognitive assessments with a median time interval of 403 days (IQR 364-474) between assessments. Based on RCI, a similar proportion of patients showed improvement and decline in each cognitive domain, while the majority exhibited no cognitive change. Among cognitively impaired patients at baseline, improvements were observed in processing speed (23.1%), visuoconstruction (40.1%) and executive functioning (20.0%). Younger age was associated with better cognitive recovery in visuoconstruction, and larger lesion volume was related to cognitive recovery in processing speed. No other predictors for cognitive recovery were identified. CONCLUSIONS: Cognitive impairment remains prevalent in young stroke even 1 year after the event. Most patients showed no cognitive change, however, recovery may have occurred in the early weeks after stroke, which was not assessed in our study. Among initially cognitively impaired patients, cognitive recovery is observed in processing speed, visuoconstruction and executive functioning. It is still not possible to predict cognitive recovery in individual patients.


Subject(s)
Cognitive Dysfunction , Ischemic Stroke , Humans , Adult , Male , Female , Ischemic Stroke/complications , Ischemic Stroke/psychology , Middle Aged , Prospective Studies , Young Adult , Neuropsychological Tests , Cognition/physiology , Adolescent , Recovery of Function , Executive Function/physiology , Age Factors
4.
Neurology ; 100(1): e49-e61, 2023 01 03.
Article in English | MEDLINE | ID: mdl-36127143

ABSTRACT

BACKGROUND AND OBJECTIVES: Causes of stroke in young adults differ from those in the elderly individuals, and in a larger percentage, no cause can be determined. To gain more insight into the etiology of (cryptogenic) stroke in the young population, we investigated whether trigger factors, such as short-lasting exposure to toxins or infection, may play a role. METHODS: Patients aged 18-49 years with a first-ever ischemic stroke or intracerebral hemorrhage (ICH) in 17 participating centers in the Netherlands completed a questionnaire about exposure to 9 potential trigger factors in hazard periods and on a regular yearly basis. A case-crossover design was used to assess relative risks (RRs) with 95% confidence intervals (95% CIs) by the Mantel-Haenszel case-crossover method, for any stroke (ischemic stroke and ICH combined) and for different etiologic subgroups of ischemic stroke. RESULTS: One thousand one hundred forty-six patients completed the questionnaire (1,043 patients with an ischemic stroke and 103 with an ICH, median age 44.0 years, 52.6% men). For any stroke, an increased risk emerged within 1 hour of cola consumption (RR 2.0, 95% CI 1.5-2.8) and vigorous physical exercise (RR 2.6, 95% CI 2.2-3.0), within 2 hours after sexual activity (RR 2.4, 95% CI 1.6-3.5), within 4 hours after illicit drug use (RR 2.8, 95% CI 1.7-4.9), and within 24 hours after fever or flu-like disease (RR 14.1, 95% CI 10.5-31.2; RR 13.9, 95% CI 8.9-21.9). Four trigger factors increased the risk of other determined and cryptogenic ischemic stroke, 3 that of cardioembolic stroke, 2 that of large vessel atherosclerosis and likely atherothrombotic stroke combined and stroke with multiple causes, and none that of stroke due to small vessel disease. DISCUSSION: We identified cola consumption, vigorous physical exercise, sexual activity, illicit drug use, fever, and flu-like disease as potential trigger factors for stroke in the young population and found differences in the type and number of trigger factors associated with different etiologic subgroups of ischemic stroke. These findings might help in better understanding the pathophysiologic mechanisms of (cryptogenic) stroke in the young population.


Subject(s)
Illicit Drugs , Ischemic Stroke , Stroke , Aged , Male , Humans , Young Adult , Adult , Female , Cross-Over Studies , Risk Factors , Stroke/epidemiology , Stroke/etiology , Cerebral Hemorrhage/etiology , Cerebral Hemorrhage/complications , Ischemic Stroke/complications
5.
Stroke ; 54(2): 439-447, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36511150

ABSTRACT

BACKGROUND: Identification of risk factors and causes of stroke is key to optimize treatment and prevent recurrence. Up to one-third of young patients with stroke have a cryptogenic stroke according to current classification systems (Trial of ORG 10172 in Acute Stroke Treatment [TOAST] and atherosclerosis, small vessel disease, cardiac pathology, other causes, dissection [ASCOD]). The aim was to identify risk factors and leads for (new) causes of cryptogenic ischemic stroke in young adults, using the pediatric classification system from the IPSS study (International Pediatric Stroke Study). METHODS: This is a multicenter prospective cohort study conducted in 17 hospitals in the Netherlands, consisting of 1322 patients aged 18 to 49 years with first-ever, imaging confirmed, ischemic stroke between 2013 and 2021. The main outcome was distribution of risk factors according to IPSS classification in patients with cryptogenic and noncryptogenic stroke according to the TOAST and ASCOD classification. RESULTS: The median age was 44.2 years, and 697 (52.7%) were men. Of these 1322 patients, 333 (25.2%) had a cryptogenic stroke according to the TOAST classification. Additional classification using the ASCOD criteria reduced the number patients with cryptogenic stroke from 333 to 260 (19.7%). When risk factors according to the IPSS were taken into account, the number of patients with no potential cause or risk factor for stroke reduced to 10 (0.8%). CONCLUSIONS: Among young adults aged 18 to 49 years with a cryptogenic ischemic stroke according to the TOAST classification, risk factors for stroke are highly prevalent. Using a pediatric classification system provides new leads for the possible causes in cryptogenic stroke, and could potentially lead to more tailored treatment for young individuals with stroke.


Subject(s)
Atherosclerosis , Ischemic Stroke , Stroke , Male , Humans , Young Adult , Child , Adult , Female , Ischemic Stroke/complications , Prospective Studies , Stroke/therapy , Risk Factors , Atherosclerosis/complications
7.
Sci Rep ; 7(1): 5110, 2017 07 11.
Article in English | MEDLINE | ID: mdl-28698556

ABSTRACT

The anatomical location of imaging features is of crucial importance for accurate diagnosis in many medical tasks. Convolutional neural networks (CNN) have had huge successes in computer vision, but they lack the natural ability to incorporate the anatomical location in their decision making process, hindering success in some medical image analysis tasks. In this paper, to integrate the anatomical location information into the network, we propose several deep CNN architectures that consider multi-scale patches or take explicit location features while training. We apply and compare the proposed architectures for segmentation of white matter hyperintensities in brain MR images on a large dataset. As a result, we observe that the CNNs that incorporate location information substantially outperform a conventional segmentation method with handcrafted features as well as CNNs that do not integrate location information. On a test set of 50 scans, the best configuration of our networks obtained a Dice score of 0.792, compared to 0.805 for an independent human observer. Performance levels of the machine and the independent human observer were not statistically significantly different (p-value = 0.06).


Subject(s)
Neuroimaging , White Matter/diagnostic imaging , Aged , Aged, 80 and over , Decision Making , Female , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Middle Aged , Neural Networks, Computer
8.
Med Phys ; 43(12): 6246, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27908171

ABSTRACT

PURPOSE: White matter hyperintensities (WMH) are seen on FLAIR-MRI in several neurological disorders, including multiple sclerosis, dementia, Parkinsonism, stroke and cerebral small vessel disease (SVD). WMHs are often used as biomarkers for prognosis or disease progression in these diseases, and additionally longitudinal quantification of WMHs is used to evaluate therapeutic strategies. Human readers show considerable disagreement and inconsistency on detection of small lesions. A multitude of automated detection algorithms for WMHs exists, but since most of the current automated approaches are tuned to optimize segmentation performance according to Jaccard or Dice scores, smaller WMHs often go undetected in these approaches. In this paper, the authors propose a method to accurately detect all WMHs, large as well as small. METHODS: A two-stage learning approach was used to discriminate WMHs from normal brain tissue. Since small and larger WMHs have quite a different appearance, the authors have trained two probabilistic classifiers: one for the small WMHs (⩽3 mm effective diameter) and one for the larger WMHs (>3 mm in-plane effective diameter). For each size-specific classifier, an Adaboost is trained for five iterations, with random forests as the basic classifier. The feature sets consist of 22 features including intensities, location information, blob detectors, and second order derivatives. The outcomes of the two first-stage classifiers were combined into a single WMH likelihood by a second-stage classifier. Their method was trained and evaluated on a dataset with MRI scans of 362 SVD patients (312 subjects for training and validation annotated by one and 50 for testing annotated by two trained raters). To analyze performance on the separate test set, the authors performed a free-response receiving operating characteristic (FROC) analysis, instead of using segmentation based methods that tend to ignore the contribution of small WMHs. RESULTS: Experimental results based on FROC analysis demonstrated a close performance of the proposed computer aided detection (CAD) system to human readers. While an independent reader had 0.78 sensitivity with 28 false positives per volume on average, their proposed CAD system reaches a sensitivity of 0.73 with the same number of false positives. CONCLUSIONS: The authors have developed a CAD system with all its ingredients being optimized for a better detection of WMHs of all size, which shows performance close to an independent reader.


Subject(s)
Cerebral Small Vessel Diseases/diagnostic imaging , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging , White Matter/diagnostic imaging , Automation , Humans
9.
Neurology ; 87(12): 1212-9, 2016 Sep 20.
Article in English | MEDLINE | ID: mdl-27521431

ABSTRACT

OBJECTIVE: To study the long-term prevalence of small vessel disease after young stroke and to compare this to healthy controls. METHODS: This prospective cohort study comprises 337 patients with an ischemic stroke or TIA, aged 18-50 years, without a history of TIA or stroke. In addition, 90 age- and sex-matched controls were included. At follow-up, lacunes, microbleeds, and white matter hyperintensity (WMH) volume were assessed using MRI. To investigate the relation between risk factors and small vessel disease, logistic and linear regression were used. RESULTS: After mean follow-up of 9.9 (SD 8.1) years, 337 patients were included (227 with an ischemic stroke and 110 with a TIA). Mean age of patients was 49.8 years (SD 10.3) and 45.4% were men; for controls, mean age was 49.4 years (SD 11.9) and 45.6% were men. Compared with controls, patients more often had at least 1 lacune (24.0% vs 4.5%, p < 0.0001). In addition, they had a higher WMH volume (median 1.5 mL [interquartile range (IQR) 0.5-3.7] vs 0.4 mL [IQR 0.0-1.0], p < 0.001). Compared with controls, patients had the same volume WMHs on average 10-20 years earlier. In the patient group, age at stroke (ß = 0.03, 95% confidence interval [CI] 0.02-0.04) hypertension (ß = 0.22, 95% CI 0.04-0.39), and smoking (ß = 0.18, 95% CI 0.01-0.34) at baseline were associated with WMH volume. CONCLUSIONS: Patients with a young stroke have a higher burden of small vessel disease than controls adjusted for confounders. Cerebral aging seems accelerated by 10-20 years in these patients, which may suggest an increased vulnerability to vascular risk factors.


Subject(s)
Brain/diagnostic imaging , Cerebral Small Vessel Diseases/complications , Cerebral Small Vessel Diseases/diagnostic imaging , Stroke/complications , Stroke/diagnostic imaging , Adolescent , Adult , Brain Ischemia/complications , Brain Ischemia/diagnostic imaging , Brain Ischemia/epidemiology , Brain Ischemia/physiopathology , Cerebral Small Vessel Diseases/epidemiology , Cerebral Small Vessel Diseases/physiopathology , Disease Progression , Female , Follow-Up Studies , Humans , Male , Middle Aged , Prevalence , Prospective Studies , Risk Factors , Stroke/epidemiology , Stroke/physiopathology , White Matter/diagnostic imaging , Young Adult
10.
Sci Rep ; 6: 28318, 2016 06 21.
Article in English | MEDLINE | ID: mdl-27324690

ABSTRACT

Previous analyses of the Atlantic cod genome showed unique combinations of lacking and expanded number of genes for the immune system. The present study examined lysozyme activity, lysozyme gene distribution and expression in cod. Enzymatic assays employing specific bacterial lysozyme inhibitors provided evidence for presence of g-type, but unexpectedly not for c-type lysozyme activity. Database homology searches failed to identify any c-type lysozyme gene in the cod genome or in expressed sequence tags from cod. In contrast, we identified four g-type lysozyme genes (LygF1a-d) constitutively expressed, although differentially, in all cod organs examined. The active site glutamate residue is replaced by alanine in LygF1a, thus making it enzymatic inactive, while LygF1d was found in two active site variants carrying alanine or glutamate, respectively. In vitro and in vivo infection by the intracellular bacterium Francisella noatunensis gave a significantly reduced LygF1a and b expression but increased expression of the LygF1c and d genes as did also the interferon gamma (IFNγ) cytokine. These results demonstrate a lack of c-type lysozyme that is unprecedented among vertebrates. Our results further indicate that serial gene duplications have produced multiple differentially regulated cod g-type lysozymes with specialised functions potentially compensating for the lack of c-type lysozymes.


Subject(s)
Fish Proteins/genetics , Gadus morhua/genetics , Muramidase/genetics , Amino Acid Sequence , Animals , Cells, Cultured , Chickens/genetics , Fish Diseases/enzymology , Fish Diseases/immunology , Fish Diseases/microbiology , Fish Proteins/chemistry , Fish Proteins/metabolism , Francisella/immunology , Gadus morhua/immunology , Gadus morhua/metabolism , Geese/genetics , Gene Expression , Interferon-gamma/genetics , Interferon-gamma/metabolism , Lipopolysaccharides/pharmacology , Macrophages/immunology , Macrophages/metabolism , Models, Molecular , Muramidase/chemistry , Muramidase/metabolism , Organ Specificity/immunology , Phylogeny
12.
Neurology ; 85(18): 1569-77, 2015 Nov 03.
Article in English | MEDLINE | ID: mdl-26446068

ABSTRACT

OBJECTIVE: To investigate the relation between baseline cerebral small vessel disease (SVD) and the risk of incident parkinsonism using different MRI and diffusion tensor imaging (DTI) measures. METHODS: In the Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort (RUN DMC) study, a prospective cohort study, 503 elderly participants with SVD and without parkinsonism were included in 2006. During follow-up (2011-2012), parkinsonism was diagnosed according to UK Brain Bank criteria. Cox regression analysis was used to investigate the association between baseline imaging measures and incident all-cause parkinsonism and vascular parkinsonism (VP). Tract-based spatial statistics analysis was used to identify differences in baseline DTI measures of white matter (WM) tracts between participants with VP and without parkinsonism. RESULTS: Follow-up was available from 501 participants (mean age 65.6 years; mean follow-up duration 5.2 years). Parkinsonism developed in 20 participants; 15 were diagnosed with VP. The 5-year risk of (any) parkinsonism was increased for those with a high white matter hyperintensity (WMH) volume (hazard ratio [HR] 1.8 per SD increase, 95% confidence interval [CI] 1.3-2.4) and a high number of lacunes (HR 1.4 per number increase, 95% CI 1.1-1.8) at baseline. For VP, this risk was also increased by the presence of microbleeds (HR 5.7, 95% CI 1.9-16.8) and a low gray matter volume (HR 0.4 per SD increase, 95% CI 0.2-0.8). Lower fractional anisotropy values in bifrontal WM tracts involved in movement control were observed in participants with VP compared to participants without parkinsonism. CONCLUSIONS: SVD at baseline, especially a high WMH volume and a high number of lacunes, is associated with incident parkinsonism. Our findings favor a role of SVD in the etiology of parkinsonism.


Subject(s)
Brain/pathology , Cerebral Small Vessel Diseases/epidemiology , Leukoencephalopathies/epidemiology , Parkinsonian Disorders/epidemiology , Aged , Aged, 80 and over , Cerebral Small Vessel Diseases/pathology , Cohort Studies , Diffusion Tensor Imaging , Female , Humans , Image Processing, Computer-Assisted , Incidence , Leukoencephalopathies/pathology , Magnetic Resonance Imaging , Male , Middle Aged , Parkinsonian Disorders/pathology , Proportional Hazards Models , Prospective Studies
13.
Hum Brain Mapp ; 36(7): 2432-42, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25757914

ABSTRACT

Memory impairment after stroke in young adults is poorly understood. In elderly stroke survivors memory impairments and the concomitant loss of hippocampal volume are usually explained by coexisting neurodegenerative disease (e.g., amyloid pathology) in interaction with stroke. However, neurodegenerative disease, such as amyloid pathology, is generally absent at young age. Accumulating evidence suggests that infarction itself may cause secondary neurodegeneration in remote areas. Therefore, we investigated the relation between long-term memory performance and hippocampal volume in young patients with first-ever ischemic stroke. We studied all consecutive first-ever ischemic stroke patients, aged 18-50 years, admitted to our academic hospital center between 1980 and 2010. Episodic memory of 173 patients was assessed using the Rey Auditory Verbal Learning Test and the Rey Complex Figure and compared with 87 stroke-free controls. Hippocampal volume was determined using FSL-FIRST, with manual correction. On average 10 years after stroke, patients had smaller ipsilateral hippocampal volumes compared with controls after left-hemispheric stroke (5.4%) and right-hemispheric stroke (7.7%), with most apparent memory dysfunctioning after left-hemispheric stroke. A larger hemispheric stroke was associated with a smaller ipsilateral hippocampal volume (b=-0.003, P<0.0001). Longer follow-up duration was associated with smaller ipsilateral hippocampal volume after left-hemispheric stroke (b=-0.028 ml, P=0.002) and right-hemispheric stroke (b=-0.015 ml, P=0.03). Our results suggest that infarction is associated with remote injury to the hippocampus, which may lower or expedite the threshold for cognitive impairment or even dementia later in life.


Subject(s)
Brain Ischemia/complications , Hippocampus/pathology , Memory Disorders/pathology , Memory, Episodic , Memory, Long-Term/physiology , Stroke/complications , Adolescent , Adult , Atrophy/pathology , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Male , Memory Disorders/etiology , Middle Aged , Young Adult
14.
Fish Shellfish Immunol ; 44(1): 66-78, 2015 May.
Article in English | MEDLINE | ID: mdl-25655332

ABSTRACT

Phagocyte recognition of lipopolysaccharide (LPS) is an early key event for triggering the host innate immune response necessary for clearance of invading bacteria. The ability of fishes to recognise LPS has been questioned as contradictory results have been presented. We show here that monocyte/macrophage cultures from Atlantic cod (Gadus morhua) and Atlantic salmon (Salmo salar) respond with an increased expression of inflammatory and antibacterial genes to both crude and ultrapure Escherichia coli LPS. Crude LPS produces higher induction than the ultrapure LPS type in both species in vitro as well as in vivo in cod injected with LPS. Crude LPS gave, in contrast to ultrapure LPS, an additional weak up-regulation of antiviral genes in salmon macrophages, most likely because of contaminants in the LPS preparation. Increased levels of chicken (c)-type lysozyme transcripts and enzyme activity were measured in salmon macrophages following ultrapure LPS stimulation demonstrating not only increased transcription but also translation. Simultaneous use and even pre-treatment with bovine sera suppressed the LPS-induced expression thereby reflecting the presence of transcription inhibitory components in sera. Together, these findings show that both cod and salmon recognise LPS per se and that the observed induction is highly dependent on the absence of sera.


Subject(s)
Anti-Bacterial Agents/metabolism , Fish Proteins/genetics , Gadus morhua/immunology , Gene Expression Regulation , Immunity, Innate , Lipopolysaccharides/immunology , Salmo salar/immunology , Animals , Escherichia coli/physiology , Fish Proteins/metabolism , Gadus morhua/genetics , Macrophages/immunology , Muramidase/metabolism , Salmo salar/genetics
15.
Clin Anat ; 27(3): 296-303, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24357119

ABSTRACT

Eight factors are claimed to have a negative influence on anatomical knowledge of medical students: (1) teaching by nonmedically qualified teachers, (2) the absence of a core anatomy curriculum, (3) decreased use of dissection as a teaching tool, (4) lack of teaching anatomy in context, (5) integrated curricula (problem-based learning or systems-based curricula), (6) inadequate assessment of anatomical knowledge, (7) decreased anatomy teaching time, and (8) neglect of vertical integration of anatomy teaching. A recent review revealed a lack of evidence underpinning any of the claims owing to the poor quality of papers, and recommendations were made for education and research on teaching in context and the implementation of vertical integration and of assessment strategies. In this article, we will describe the alleged factors fully, revealing additional recommendations for improving anatomy education by promoting recognition for teaching in institutions, by enhancing the professional recognition of anatomists through the implementation of a national postgraduate training program, and by encouraging anatomists to participate in educational research.


Subject(s)
Anatomy/education , Education, Medical, Undergraduate/methods , Problem-Based Learning/methods , Quality Improvement , Cadaver , Curriculum/standards , Dissection/education , Dissection/methods , Education, Medical, Undergraduate/standards , Educational Measurement/standards , Humans , Problem-Based Learning/standards
16.
BMC Med Educ ; 13: 152, 2013 Nov 19.
Article in English | MEDLINE | ID: mdl-24252155

ABSTRACT

BACKGROUND: To get insight in how theoretical knowledge is transformed into clinical skills, important information may arise from mapping the development of anatomical knowledge during the undergraduate medical curriculum. If we want to gain a better understanding of teaching and learning in anatomy, it may be pertinent to move beyond the question of how and consider also the what, why and when of anatomy education. METHODS: A purposive sample of 78 medical students from the 2nd, 3rd, 4th and 6th year of a PBL curriculum participated in 4 focus groups. Each group came together twice, and all meetings were recorded and transcribed verbatim. Data were analysed with template analysis using a phenomenographical approach. RESULTS: Five major topics emerged and are described covering the students' perceptions on their anatomy education and anatomical knowledge: 1) motivation to study anatomy, 2) the relevance of anatomical knowledge, 3) assessment of anatomical knowledge, 4) students' (in)security about their anatomical knowledge and 5) the use of anatomical knowledge in clinical practice. CONCLUSIONS: Results indicated that a PBL approach in itself was not enough to ensure adequate learning of anatomy, and support the hypothesis that educational principles like time-on-task and repetition, have a stronger impact on students' perceived and actual anatomical knowledge than the educational approach underpinning a curriculum. For example, students state that repetitive studying of the subject increases retention of knowledge to a greater extent than stricter assessment, and teaching in context enhances motivation and transfer. Innovations in teaching and assessment, like spiral curriculum, teaching in context, teaching for transfer and assessment for learning (rewarding understanding and higher order cognitive skills), are required to improve anatomy education.


Subject(s)
Anatomy/education , Education, Medical, Undergraduate/methods , Problem-Based Learning , Students, Medical/psychology , Adult , Curriculum , Education, Medical, Undergraduate/organization & administration , Educational Measurement , Female , Humans , Male , Motivation , Young Adult
17.
Mar Drugs ; 11(11): 4279-93, 2013 Oct 30.
Article in English | MEDLINE | ID: mdl-24177674

ABSTRACT

The screening of extracts from marine organisms is a widely used strategy to discover new drug leads. A common problem in the screening process is the generation of false positive hits through unspecific effects from the complex chemical composition of the crude extracts. In this study, we explored a combination of a fluorescence resonance energy transfer (FRET) based activity assay and a surface plasmon resonance (SPR) based binding assay to avoid this problem. An aqueous extract was prepared from rest raw material of the Norwegian spring spawning herring, and further fractionated by methanol solubility and solid phase extraction. FRET based activity assays were used to determine the influence of each extract on the activity of different proteases. Several extracts showed more than 50% inhibition. The inhibition mechanisms were elucidated by SPR based competition experiments with known inhibitors. For the secreted aspartic proteases 1, 2, 3 and HIV-1 protease, the results indicated that some extracts contain inhibitors interacting specifically with the active site of the enzymes. The study shows that a combination of an activity assay and an SPR based binding assay is a powerful tool to identify potent inhibitors in marine extracts. Furthermore, the study shows that marine vertebrates offer an interesting source for new bioactive compounds, although they have rarely been explored for this purpose.


Subject(s)
Aquatic Organisms/chemistry , Peptide Hydrolases/metabolism , Protease Inhibitors/chemistry , Biological Assay/methods , Protease Inhibitors/pharmacology , Spectrum Analysis/methods , Surface Plasmon Resonance/methods
18.
Neurobiol Aging ; 34(9): 2225-30, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23623602

ABSTRACT

Cerebral small vessel disease (SVD), including white matter lesions (WML) and lacunar infarcts, is related to objective cognitive impairment but also to subjective cognitive failures (SCF). SCF have reported to be an early predictor of dementia. Cerebral microbleeds (MB) are another manifestation of SVD and have been related to cognitive impairment, but the role of MB in SCF has never been studied. We therefore investigated whether MB are related to SCF among non-demented elderly individuals with SVD, independent of coexisting WML and lacunar infarcts. The RUN DMC study is a prospective cohort study among 503 older persons with cerebral SVD between 50 and 85 years of age. All participants underwent FLAIR and T2* scanning. SCF, subjective memory failures (SMF), and subjective executive failures (SEF) were assessed. The relation between SCF and the presence, number and location of MB was assessed by linear regression analyses adjusted for age, sex, education, depressive symptoms, cognitive function, total brain volume, normalized hippocampal volume, territorial infarcts, WML, and lacunar infarcts. MB were present in 11%. We found a relation between the presence, total number and lobar located MB, and SCF, SMF, and SEF and the reported progression of these failures, especially in participants with good objective cognitive function. In conclusion, MB are related to SCF independent of co-existing WML and lacunar infarcts, especially in those with good objective cognitive performance. These results suggest that MB are associated with the earliest manifestations of cognitive impairment. MB may help us to understand the role of the ever-expanding spectrum of SVD in cognitive impairment.


Subject(s)
Aging/pathology , Brain/pathology , Cerebral Hemorrhage/complications , Cerebral Hemorrhage/pathology , Cerebral Small Vessel Diseases/complications , Cerebral Small Vessel Diseases/pathology , Cognition Disorders/etiology , Cognition Disorders/pathology , Diffusion Magnetic Resonance Imaging , Aged , Aged, 80 and over , Cerebral Hemorrhage/diagnosis , Cerebral Small Vessel Diseases/diagnosis , Cognition Disorders/diagnosis , Cohort Studies , Humans , Middle Aged , Prospective Studies , Risk Factors
19.
Dev Comp Immunol ; 40(1): 11-9, 2013 May.
Article in English | MEDLINE | ID: mdl-23396098

ABSTRACT

Lysozymes represent important innate immune components against bacteria. In this study, Atlantic salmon (Salmo salar) goose (g-) and chicken (c-) types of lysozyme were subjected to protein characterisations and tissue expression analyses. Specific bacterial protein inhibitors of g- and c-type lysozymes were employed to discriminate between respective enzyme activities. Blood, gills and liver contained activities exclusive for the g-type lysozyme. Only haematopoietic organs (head kidney and spleen) contained enzyme activities of both g- and c-lysozyme enzymes and c-type activity was not found outside these organs. Gene transcript levels proportional to enzyme activity levels were detected for the g-type lysozyme but not for the c-type. In vitro studies revealed significant induction of c-type gene expression and enzyme activity in macrophages after incubation with lipopolysaccharide (LPS) while expression of the g-type lysozyme gene was unaffected. The activity of purified native c-type enzyme was profoundly reduced by divalent cations and displayed low tolerance to monovalent cations, while the native g-type lysozyme was stimulated by monovalent cations and tolerated low concentrations of divalent cations. Activities of both enzymes increased with temperature elevations up to 60°C. The native g-type lysozyme responses to temperature in particular are in apparent conflict to the ones for the recombinant salmon g-lysozyme. Our results imply separate expression regulations and different functions of c- and g-type lysozymes in salmon. LPS-induced expression of c-type lysozyme and broad constitutive tissue distribution of g-type lysozyme in salmon is different from findings in other studied fish species.


Subject(s)
Fish Proteins/metabolism , Macrophages/metabolism , Muramidase/metabolism , Salmo salar/immunology , Animals , Blood Cells/metabolism , Cations, Divalent/metabolism , Cations, Monovalent/metabolism , Cells, Cultured , Enzyme Activation , Fish Proteins/genetics , Fish Proteins/isolation & purification , Gene Expression Profiling , Gene Expression Regulation , Gills/metabolism , Head Kidney/metabolism , Hot Temperature , Immunity, Innate , Lipopolysaccharides/immunology , Liver/metabolism , Macrophages/immunology , Muramidase/genetics , Muramidase/isolation & purification , Organ Specificity , Salmo salar/genetics , Spleen/metabolism
20.
Fertil Steril ; 99(5): 1419-27, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23357454

ABSTRACT

OBJECTIVE: To determine the effect of audits and feedback on the level of patient-centeredness in fertility care, and to obtain a more in-depth understanding of professionals' views on patient-centered care and achieving improvements. DESIGN: Mixed-method design, using semistructured in-depth interviews and patient questionnaires. SETTING: Fifteen Dutch fertility clinics. PATIENT(S): Women in infertility treatment (quantitative section) and fertility care professionals (qualitative section). INTERVENTION(S): Audit of the level of patient-centeredness of care, and feedback provided to clinics by a personalized paper-based feedback report. MAIN OUTCOME MEASURE(S): Quantitative section: the patient-reported differences in the level of patient-centered fertility care between 2009 and 2011 measured by the Patient-Centeredness Questionnaire-Infertility. Qualitative section: professionals views on improving patient-centered fertility care arranged into a Hibbard framework for behavioral change. RESULT(S): Multilevel regression analysis showed no statistically significant differences between the overall levels of patient-centeredness in 2009 and 2011. Qualitative research showed that professionals' urge to change and their ability to translate feedback were suboptimal to achieve behavioral change. CONCLUSION(S): Audits and feedback alone are not enough to improve the level of patient-centeredness in fertility care. Increasing professionals' desire to change and their ability to translate feedback about their performance into an optimal quality improvement strategy appear to be the key issues.


Subject(s)
Feedback, Psychological , Infertility, Female/psychology , Infertility, Female/therapy , Patient-Centered Care/methods , Professional-Patient Relations , Reproductive Medicine/methods , Adult , Ambulatory Care Facilities/standards , Female , Humans , Medical Audit , Middle Aged , Netherlands , Patient Satisfaction , Patient-Centered Care/standards , Psychological Theory , Qualitative Research , Quality of Health Care , Reproductive Medicine/standards , Surveys and Questionnaires , Young Adult
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