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1.
Intell Based Med ; 6: 100071, 2022.
Article in English | MEDLINE | ID: mdl-35958674

ABSTRACT

Background: The COVID-19 pandemic continues to overwhelm intensive care units (ICUs) worldwide, and improved prediction of mortality among COVID-19 patients could assist decision making in the ICU setting. In this work, we report on the development and validation of a dynamic mortality model specifically for critically ill COVID-19 patients and discuss its potential utility in the ICU. Methods: We collected electronic medical record (EMR) data from 3222 ICU admissions with a COVID-19 infection from 25 different ICUs in the Netherlands. We extracted daily observations of each patient and fitted both a linear (logistic regression) and non-linear (random forest) model to predict mortality within 24 h from the moment of prediction. Isotonic regression was used to re-calibrate the predictions of the fitted models. We evaluated the models in a leave-one-ICU-out (LOIO) cross-validation procedure. Results: The logistic regression and random forest model yielded an area under the receiver operating characteristic curve of 0.87 [0.85; 0.88] and 0.86 [0.84; 0.88], respectively. The recalibrated model predictions showed a calibration intercept of -0.04 [-0.12; 0.04] and slope of 0.90 [0.85; 0.95] for logistic regression model and a calibration intercept of -0.19 [-0.27; -0.10] and slope of 0.89 [0.84; 0.94] for the random forest model. Discussion: We presented a model for dynamic mortality prediction, specifically for critically ill COVID-19 patients, which predicts near-term mortality rather than in-ICU mortality. The potential clinical utility of dynamic mortality models such as benchmarking, improving resource allocation and informing family members, as well as the development of models with more causal structure, should be topics for future research.

2.
Sci Rep ; 12(1): 5986, 2022 04 08.
Article in English | MEDLINE | ID: mdl-35396521

ABSTRACT

Rhythmic flickering visual stimulation produces steady-state visually evoked potentials (SSVEPs) in electroencephalogram (EEG) recordings. Based on electrode-level analyses, two dichotomous models of the underpinning mechanisms leading to SSVEP generation have been proposed: entrainment or superposition, i.e., phase-alignment or independence of endogenous brain oscillations from flicker-induced oscillations, respectively. Electrode-level analyses, however, represent an averaged view of underlying 'source-level' activity, at which variability in SSVEPs may lie, possibly suggesting the co-existence of multiple mechanisms. To probe this idea, we investigated the variability of SSVEPs derived from the sources underpinning scalp EEG responses during presentation of a flickering radial checkerboard. Flicker was presented between 6 and 12 Hz in 1 Hz steps, and at individual alpha frequency (IAF i.e., the dominant frequency of endogenous alpha oscillatory activity). We tested whether sources of endogenous alpha activity could be dissociated according to evoked responses to different flicker frequencies relative to IAF. Occipitoparietal sources were identified by temporal independent component analysis, maximal resting-state alpha power at IAF and source localisation. The pattern of SSVEPs to rhythmic flicker relative to IAF was estimated by correlation coefficients, describing the correlation between the peak-to-peak amplitude of the SSVEP and the absolute distance of the flicker frequency from IAF across flicker conditions. We observed extreme variability in correlation coefficients across sources, ranging from -0.84 to 0.93, with sources showing largely different coefficients co-existing within subjects. This result demonstrates variation in evoked responses to flicker across sources of endogenous alpha oscillatory activity. Data support the idea of multiple SSVEP mechanisms.


Subject(s)
Electroencephalography , Evoked Potentials, Visual , Brain , Electrodes , Humans , Photic Stimulation
3.
J Nutr Health Aging ; 25(3): 287-294, 2021.
Article in English | MEDLINE | ID: mdl-33575718

ABSTRACT

OBJECTIVES: To determine prevalence of vitamin B12 and folate deficiency and associations with cognitive performance in participants recruited for the Cognitive Health in Ageing Register: Investigational, Observational, and Trial Studies in Dementia Research: Prospective Readiness cOhort Study (CHARIOTPRO) SubStudy (CPRO-SS). DESIGN: Cross-sectional analysis of data collected in the screening phase for the CPRO-SS. SETTING: Participants were recruited from the Chariot Register at Imperial College London comprising approximately 39,000 community dwelling volunteers. PARTICIPANTS: Community dwelling individuals aged 60-85 years with B vitamin biomarker measures available were included (n=1946). After medical history and other exclusions, 1347 cognitively healthy participants were included for analysis of cognitive data. MEASUREMENTS: Cognitive status was assessed with the Repeatable Battery for Neuropsychological Status (RBANS). Assays included vitamin B12 and folate, followed by serum methylmalonic acid and homocysteine levels for those with low vitamin B12. Gender-specific linear regression analysis was performed for associations between cognition and biomarkers. Non-gender specific regression for groups graded by B vitamin deficiency severity were also performed. RESULTS: Vitamin B12 deficiency (<148pmol/L) was found in 17.2% of individuals and folate deficiency (<10nmol/L) in 1% of our participants. Low vitamin B12 was associated with poorer memory (p<0.03) in men. A high BMI predicted poorer attention and visuospatial indices (p<0.05). A regression analysis by B12 level revealed associations with poorer attention (ß -6.46; p=0.004) for the deficient group and with immediate memory (ß -2.99; p=0.019) for those categorised as severely deficient. CONCLUSION: Older men and women are prone to vitamin B12 deficiency with associated subtle and different domain-specific disruptive effects in measures of memory and attention. Elevated homocysteine and methylmalonic acid contributed to poorer cognitive performance. Novel groups at particular risk of cognitive deficit were identified for future interventional studies in this field.


Subject(s)
Cognition/physiology , Folic Acid/blood , Vitamin B 12/blood , Aged , Aged, 80 and over , Cohort Studies , Cross-Sectional Studies , Female , Healthy Volunteers , Humans , Male , Middle Aged , Prospective Studies
4.
J Crit Care ; 60: 111-115, 2020 12.
Article in English | MEDLINE | ID: mdl-32799179

ABSTRACT

PURPOSE: Since the SARS-CoV-2 pandemic, countries are overwhelmed by critically ill Coronavirus disease 2019 (COVID-19) patients. As ICU capacity becomes limited we characterized critically ill COVID-19 patients in the Netherlands. METHODS: In this case series, COVID-19 patients admitted to the ICU of the Jeroen Bosch Hospital were included from March 9 to April 7, 2020. COVID-19 was confirmed by a positive result by a RT-PCR of a specimen collected by nasopharyngeal swab. Clinical data were extracted from medical records. RESULTS: The mean age of the 50 consecutively included critically ill COVID-19 patients was 65 ± 10 years, the mean BMI was 29 ± 4.7 and 66% were men. Seventy-eight percent of patients had ≥1 comorbidity, 34% had hypertension. Ninety-six percent of patients required mechanical ventilation and 80% were ventilated in prone position. Venous thromboembolism was recognized in 36% of patients. Seventy-four percent of patients survived and were successfully discharged from the ICU, the remaining 26% died (median follow up 86 days). The length of invasive ventilation in survivors was 15 days (IQR 12-31). CONCLUSIONS: The survival rate of COVID-19 critically ill patients in our population is considerably better than previously reported. Thrombotic complications are commonly found and merit clinical attention. TRIAL REGISTRATION NUMBER: NL2020.07.04.01.


Subject(s)
COVID-19 Drug Treatment , Respiration, Artificial , Adult , Aged , Aged, 80 and over , Body Mass Index , COVID-19 Nucleic Acid Testing , Critical Care , Critical Illness/epidemiology , Female , Hospitalization , Humans , Intensive Care Units , Lung , Male , Middle Aged , Netherlands/epidemiology , Pandemics , Patient Discharge , Real-Time Polymerase Chain Reaction
5.
Am Heart J ; 226: 60-68, 2020 08.
Article in English | MEDLINE | ID: mdl-32512291

ABSTRACT

There is much debate on the use of angiotensin receptor blockers (ARBs) in severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-infected patients. Although it has been suggested that ARBs might lead to a higher susceptibility and severity of SARS-CoV-2 infection, experimental data suggest that ARBs may reduce acute lung injury via blocking angiotensin-II-mediated pulmonary permeability, inflammation, and fibrosis. However, despite these hypotheses, specific studies on ARBs in SARS-CoV-2 patients are lacking. METHODS: The PRAETORIAN-COVID trial is a multicenter, double-blind, placebo-controlled 1:1 randomized clinical trial in adult hospitalized SARS-CoV-2-infected patients (n = 651). The primary aim is to investigate the effect of the ARB valsartan compared to placebo on the composite end point of admission to an intensive care unit, mechanical ventilation, or death within 14 days of randomization. The active-treatment arm will receive valsartan in a dosage titrated to blood pressure up to a maximum of 160 mg bid, and the placebo arm will receive matching placebo. Treatment duration will be 14 days, or until the occurrence of the primary end point or until hospital discharge, if either of these occurs within 14 days. The trial is registered at clinicaltrials.gov (NCT04335786, 2020). SUMMARY: The PRAETORIAN-COVID trial is a double-blind, placebo-controlled 1:1 randomized trial to assess the effect of valsartan compared to placebo on the occurrence of ICU admission, mechanical ventilation, and death in hospitalized SARS-CoV-2-infected patients. The results of this study might impact the treatment of SARS-CoV-2 patients globally.


Subject(s)
Angiotensin II Type 1 Receptor Blockers/therapeutic use , Betacoronavirus , Coronary Care Units , Coronavirus Infections/complications , Pneumonia, Viral/complications , Randomized Controlled Trials as Topic , Respiratory Distress Syndrome/prevention & control , Valsartan/therapeutic use , Adult , Angiotensin II Type 1 Receptor Blockers/administration & dosage , COVID-19 , Coronavirus Infections/mortality , Double-Blind Method , Drug Administration Schedule , Humans , Inpatients , Multicenter Studies as Topic , Netherlands , Pandemics , Placebos/therapeutic use , Pneumonia, Viral/mortality , Respiration, Artificial , Respiratory Distress Syndrome/mortality , SARS-CoV-2 , Time Factors , Valsartan/administration & dosage
6.
BJS Open ; 4(3): 432-437, 2020 06.
Article in English | MEDLINE | ID: mdl-32297478

ABSTRACT

BACKGROUND: Pancreatic fistula (PF) is a common complication after pancreatic surgery. It is unclear how microbes in PF fluid affect outcomes and which microbes are present after pancreatoduodenectomy (PD) and distal pancreatectomy (DP). The aim of this study was to compare the microbiological spectrum of PF fluid after PD versus DP, and its association with postoperative complications. METHODS: Bacterial strains and antibiotic resistance rates of bacterial swabs obtained from the PF fluid of patients who underwent DP or PD were analysed. Cultured bacteria were classified as Enterobacterales and as 'other intestinal and non-intestinal microorganisms' based on whether they are typically part of the normal human intestinal flora. RESULTS: A total of 847 patients had a pancreatic resection (PD 600; DP 247) between July 2007 and December 2016. Clinically relevant PF was detected in 131 patients (15·5 per cent). Bacterial swabs were obtained from 108 patients (DP 47; PD 61), of which 19 (17·6 per cent) were sterile. Enterobacterales were detected in 74 per cent of PF fluid swabs after PD, and in 34 per cent after DP. Infected, polymicrobial or multidrug-resistant PF fluid was more common after PD (rates of 95, 50 and 48 per cent respectively) than after DP (66, 26 and 6 per cent respectively). Patients with higher grade complications (Clavien-Dindo grade IV-V) or grade C PF had more Enterobacterales and multidrug-resistant Enterobacterales in the PF fluid after DP. CONCLUSION: Enterobacterales and multidrug-resistant bacteria are detected frequently after PD and DP, and are associated with more severe complications and PF in patients undergoing DP.


ANTECEDENTES: La fístula pancreática (pancreatic fistula, PF) es una complicación frecuente de la cirugía pancreática. No está claro cómo los microorganismos que se encuentran en el líquido de la PF (pancreatic fistula fluid, PFF) afectan los resultados y qué microbios están presentes después de la duodenopancreatectomía (pancreaticoduodenectomy, PD) y de la pancreatectomía distal (distal pancreatectomy, DP). El objetivo de este estudio fue comparar el espectro microbiológico del PFF después de PD versus DP y su asociación con las complicaciones postoperatorias. MÉTODOS: Se analizaron las cepas bacterianas y las tasas de resistencia a los antibióticos de las muestras bacterianas obtenidas del PFF de pacientes de nuestra institución que se sometieron a DP o PD. Las bacterias identificadas en los cultivos se clasificaron en "enterobacterias" y "otros microorganismos intestinales y no intestinales" en función de si típicamente forman parte de la flora intestinal humana normal o no. RESULTADOS: Un total de 847 pacientes se sometieron a resección pancreática (PD: 600, DP: 247) entre julio de 2007 y diciembre de 2016, y se detectó FP clínicamente relevante en 131 pacientes (15,5%). Se obtuvieron muestras bacterianas de 108 pacientes (DP n = 47, PD N = 61), de los cuales 19 (18%) eran estériles. Se detectaron enterobacterias en el 74% del PFF después de PD y en el 34% después de DP. El PFF infectado, con flora polimicrobiana o flora multirresistente fue más frecuente después de la PD (95,1%, 50%, 47,5%, respectivamente) que después de la DP (66,0%, 25,8%, 6,4%, respectivamente). Los pacientes con complicaciones de grado superior (Clavien-Dindo 4/5) o PF grado C presentaron más enterobacterias y enterobacterias multirresistentes en el PFF después de DP. CONCLUSIÓN: Las enterobacterias y las bacterias multirresistentes se detectaron con frecuencia después de la PD y la DP, y se asociaron a complicaciones más graves y PF en pacientes sometidos a DP.


Subject(s)
Bacteria/isolation & purification , Pancreatectomy/adverse effects , Pancreatic Fistula/microbiology , Pancreatic Juice/microbiology , Pancreaticoduodenectomy/adverse effects , Postoperative Complications/microbiology , Adult , Aged , Aged, 80 and over , Bacteria/classification , Female , Germany , Humans , Logistic Models , Male , Middle Aged , Multivariate Analysis , Pancreatic Fistula/etiology , Pancreatic Neoplasms/surgery , Postoperative Complications/etiology , Risk Factors , Treatment Outcome
8.
Anaesthesist ; 67(10): 738-744, 2018 10.
Article in German | MEDLINE | ID: mdl-30171286

ABSTRACT

In 1985 Mallampati et al. published a non-invasive score for the evaluation of airways (Mallampati grading scale, MGS), which originally consisted of only three different classes and has been modified several times. At present it is mostly used in the version of Samsoon and Young consisting of four different classes. Class I: soft palate, fauces, uvula, palatopharyngeal arch visible, class II: soft palate, fauces, uvula visible, class III: soft palate, base of the uvula visible and class IV: soft palate not visible. Nevertheless, other versions of MGS still exist, each having different values for sensitivity and specification. The current opinion is therefore that MGS is no longer useful as a stand-alone predictor but in combination with others it is still part of today's most relevant guidelines, such as those of the American Society of Anesthesiologists (ASA), the UK's Difficult Airway Society (DAS), the European Society of Anaesthesiology (ESA) and the German Society for Anesthesiology and Intensive Care Medicine (DGAI) and must therefore be known by anesthetists. Even in times of sophisticated tools for airway management, the procedure remains a high risk, so every anesthetist has to be prepared for and well trained in management of known and unexpected difficult airways. Evaluation of the patient's airway is a part of modern airway management to prevent problems and reduce risk of hypoxia during the procedure. The theoretical knowledge and practical skills of European anesthetists were evaluated at two international congresses, the German Anesthesia Congress (DAC) and Euroanaesthesia 2014. The DAC is an annual meeting of German speaking anesthetists, hosted by the DGAI. The Euroanaesthesia is the annual European pendant hosted by the ESA. Participation was voluntary and only physicians were allowed to take part. Theory was evaluated by a questionnaire containing open and closed questions for MGS that had to be answered by every participant alone. Apart from theory, a practical evaluation was performed. Every participant had to classify the MGS of a human airway model. The model was identical on both congresses. According to the original publication a checklist containing the factors essential for the correct performance was filled out by a supervising experienced anesthetist. During DAC 2014 n = 267 physicians participated in the study, 22 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part. A total of 245 data sets were evaluated. During Euroanaesthesia 2014 n = 298 physicians participated in the study, 68 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part and 230 data sets were evaluated. At the DAC the mean age (± SD) was 44.5 ± 9.5 years, 157 (64.1%) were male and 88 (35.9%) were female. Working experience was trainee anesthetist in 16.7% and other participants were experienced anesthetists. At the ESA the mean age (± SD) was 42.4 ± 9.5 years, 133 (57.8%) were male and 97 (42.2%) female. Trainee anesthetists were 15.2%, the rest were experienced anesthetists. The DAC participants knew Mallampati classes 1 (65%) and 4 (45%) better than 2 and 3 and there was no relevant differences to the ESA (close to 30% knew the classes 1-4 here). Classification of the airway model was correct in 62% and 67% at DAC and ESA, respectively. Most participants performed the practical evaluation correctly except the sitting position of the model. In agreement with earlier studies, these results show the lack of knowledge in evaluation of airways according to current guidelines of all relevant societies. This is likely to increase preventable risks for patients as unexpected difficult airway management increases the risk for hypoxia and intubation damage.


Subject(s)
Airway Management , Anesthesiology/education , Anesthesia/methods , Critical Care , Education, Medical , Humans , Physicians , Surveys and Questionnaires
9.
Neth J Med ; 76(6): 304, 2018 Aug.
Article in English | MEDLINE | ID: mdl-30152399
11.
Clin Exp Allergy ; 48(9): 1206-1213, 2018 09.
Article in English | MEDLINE | ID: mdl-29904971

ABSTRACT

BACKGROUND: The role of sensitization to commercially available allergens of English walnut (Juglans regia) Jug r 1, 2 and 3 in walnut allergy has been previously investigated in walnut allergic adults and was unable to explain all cases of walnut allergy. OBJECTIVES: Identify recognized walnut allergens, other than the ones previously investigated (Jug r 1-3), in walnut allergic adults and determine the sensitization frequency and diagnostic value. METHODS: Three different in-house walnut extracts were prepared and analysed on SDS-PAGE blots to identify allergenic walnut proteins. Immunoblots and immunoprecipitation, followed by LC-MS analysis, were performed to screen for, and confirm, IgE binding to walnut allergens in selected walnut allergic adults. In a cohort of 55 walnut challenged adults, including 33 allergic and 22 tolerant, sensitization to native and recombinant walnut allergen Jug r 4 was assessed using immunoblotting and immuno-line blot (EUROLINE), respectively. RESULTS: Screening of sera of 8 walnut allergic adults identified Jug r 4 as an allergen in our population. In the total cohort of 55 subjects, 5 were positive for Jug r 4 on immunoblot and 10 on EUROLINE. All but one EUROLINE positive subject had a positive food challenge (sensitivity 27%, specificity 95%, PPV 90%, NPV 47%). All 5 subjects positive on immunoblot were also positive on EUROLINE. LC-MS analysis showed a lack of Jug r 4 in the ImmunoCAP extract. Co-sensitization to other 11S albumins (eg hazelnut Cor a 9) was common in Jug r 4 sensitized subjects, potentially due to cross-reactivity. CONCLUSIONS: Walnut 11S globulin Jug r 4 is a relevant minor allergen, recognized by 27% of walnut allergic adults. It has a high positive predictive value of 90% for walnut allergy. Specific IgE against Jug r 4 occurred mostly with concomitant sensitization to other walnut components, mainly Jug r 1.


Subject(s)
Antigens, Plant/immunology , Juglans/adverse effects , Nut Hypersensitivity/immunology , Plant Proteins/immunology , Adult , Antigens, Plant/chemistry , Antigens, Plant/isolation & purification , Chromatography, Liquid , Cross Reactions/immunology , Female , Humans , Immunoassay , Immunoglobulin E/immunology , Juglans/chemistry , Male , Mass Spectrometry , Nut Hypersensitivity/diagnosis , Plant Extracts/chemistry , Plant Extracts/immunology , Plant Proteins/chemistry , Plant Proteins/isolation & purification , Sensitivity and Specificity , Skin Tests , Young Adult
12.
Clin Exp Allergy ; 48(7): 890-897, 2018 07.
Article in English | MEDLINE | ID: mdl-29542223

ABSTRACT

BACKGROUND: Screening for specific IgE against 2S albumin proteins Ara h 2 and 6 has good positive predictive value in diagnosing peanut allergy. From the third 2S member Ara h 7, 3 isoforms have been identified. Their allergenicity has not been elucidated. OBJECTIVE: This study investigated the allergenicity of Ara h 7 isoforms compared to Ara h 2 and 6. METHODS: Sensitization of 15 DBPCFC-confirmed peanut-allergic patients to recombinant Ara h 2.0201, Ara h 6.01 and isoforms of recombinant Ara h 7 was determined by IgE immunoblotting strips. A basophil activation test (BAT) was performed in 9 patients to determine IgE-cross-linking capacities of the allergens. Sensitivity to the allergens was tested in 5 patients who were sensitized to at least 1 Ara h 7 isoform, by a concentration range in the BAT. 3D prediction models and sequence alignments were used to visualize differences between isoforms and to predict allergenic epitope regions. RESULTS: Sensitization to Ara h 7.0201 was most frequent (80%) and showed to be equally potent as Ara h 2.0201 and 6.01 in inducing basophil degranulation. Sensitization to Ara h 7.0201 together with Ara h 2.0201 and/or 6.01 was observed, indicating the presence of unique epitopes compared to the other 2 isoforms. Differences between the 3 Ara h 7 isoforms were observed in C-terminal cysteine residues, pepsin and trypsin cleavage sites and 3 single amino acid substitutions. CONCLUSION & CLINICAL RELEVANCE: The majority of peanut-allergic patients are sensitized to isoform Ara h 7.0201, which is functionally as active as Ara h 2.0201 and 6.01. Unique epitopes are most likely located in the C-terminus or an allergenic loop region which is a known allergenic epitope region for Ara h 2.0201 and 6.01. Due to its unique epitopes and allergenicity, it is an interesting candidate to improve the diagnostic accuracy for peanut allergy.


Subject(s)
2S Albumins, Plant/immunology , Antigens, Plant/immunology , Basophils/immunology , Cell Degranulation/immunology , Epitopes/immunology , Peanut Hypersensitivity/immunology , 2S Albumins, Plant/chemistry , Adult , Amino Acid Sequence , Antigens, Plant/chemistry , Basophils/metabolism , Epitopes/chemistry , Female , Humans , Immunoglobulin E/immunology , Male , Middle Aged , Models, Molecular , Peanut Hypersensitivity/diagnosis , Protein Conformation , Protein Isoforms , Structure-Activity Relationship
13.
Anaesthesist ; 67(3): 198-203, 2018 03.
Article in English | MEDLINE | ID: mdl-29392357

ABSTRACT

Predicting and managing the difficult airway is a lifesaving and vital basic task for the anesthetist. Current guidelines of all important societies include thyromental distance (TMD, "Patil") as a possible predictor for a difficult airway and includes two important aspects for airway management: the mandibular space and the flexibility of the cervical spine. We evaluated knowledge and execution regarding TMD for predicting a difficult airway on participants at the Euroanaesthesia (ESA) congress and German Anaesthesia Congress (DAC) in 2014. Our evaluation consisted of a theoretical part with questions regarding general knowledge and a practical evaluation with anesthetists performing on a human airway model. Practical evaluations were performed separately from other participants. During the DAC 245 (ESA 230) physicians participated, of which 64% were male (ESA 58%). At the DAC 182 (74.3%) and ESA 82 (35.6%) participants knew about Patil/TMD. Its use as a predictive score for a difficult airway was known by 122 (49.8%; DAC) and 79 (34.4%; ESA) participants. The correct definition for intubation was given by 45 (25.7%) at the DAC and 56 (24.3%) at ESA. Only 40-41% of the participants measured the correct distance for TMD. Only 6.1-6.5% completed both the theoretical and practical parts correctly. As non-invasive TMD includes two different aspects of patient airways and is part of current guidelines, education and training must be extended to assure adequate evaluation in the future.


Subject(s)
Airway Management/methods , Anesthesiologists , Health Knowledge, Attitudes, Practice , Mandible/anatomy & histology , Thyroid Gland/anatomy & histology , Adult , Clinical Competence , Europe , Female , Humans , Intubation, Intratracheal/methods , Male , Middle Aged , Prospective Studies
14.
Nat Commun ; 8(1): 1408, 2017 11 10.
Article in English | MEDLINE | ID: mdl-29123117

ABSTRACT

The internal structure of nucleons (protons and neutrons) remains one of the greatest outstanding problems in modern nuclear physics. By scattering high-energy electrons off a proton we are able to resolve its fundamental constituents and probe their momenta and positions. Here we investigate the dynamics of quarks and gluons inside nucleons using deeply virtual Compton scattering (DVCS)-a highly virtual photon scatters off the proton, which subsequently radiates a photon. DVCS interferes with the Bethe-Heitler (BH) process, where the photon is emitted by the electron rather than the proton. We report herein the full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the regime where the scattering is expected to occur off a single quark, measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction.

15.
Phys Rev Lett ; 118(22): 222002, 2017 Jun 02.
Article in English | MEDLINE | ID: mdl-28621966

ABSTRACT

We report the first longitudinal-transverse separation of the deeply virtual exclusive π^{0} electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dσ_{L}/dt, dσ_{T}/dt, dσ_{LT}/dt, and dσ_{TT}/dt are extracted as a function of the momentum transfer to the recoil system at Q^{2}=1.75 GeV^{2} and x_{B}=0.36. The ed→edπ^{0} cross sections are found compatible with the small values expected from theoretical models. The en→enπ^{0} cross sections show a dominance from the response to transversely polarized photons, and are in good agreement with calculations based on the transversity generalized parton distributions of the nucleon. By combining these results with previous measurements of π^{0} electroproduction off the proton, we present a flavor decomposition of the u and d quark contributions to the cross section.

16.
Br J Surg ; 104(2): e182-e188, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28121036

ABSTRACT

BACKGROUND: Patients with obstructive jaundice due to periampullary tumours may undergo preoperative biliary drainage (PBD). The effect of PBD on the microbiome of the biliary system and on postoperative outcome remains unclear. METHODS: A single-centre retrospective study of patients with obstructive jaundice due to periampullary cancer, treated between July 2007 and July 2015, was undertaken. Intraoperative bile samples were obtained for microbiological analysis after transection of the common bile duct. Postoperative complications were registered. RESULTS: Of 290 patients treated, intraoperative bile samples were present for 172 patients (59·3 per cent) who had PBD and 118 (40·7 per cent) who did not. Contamination of bile was increased significantly in patients who underwent stenting (97·1 per cent versus 18·6 per cent in those without stenting; P < 0·001). PBD resulted in a shift in the biliary microbiome from Escherichia coli in non-stented patients (45 per cent versus 19·2 per cent in stented patients; P = 0·009) towards increased contamination with Enterococcus faecalis (9 versus 37·7 per cent respectively; P = 0·008) and Enterobacter cloacae (0 versus 20·4 per cent; P = 0·033). This shift was associated with a high incidence of bacterial resistance against ampicillin-sulbactam (63·6 per cent versus 18 per cent in patients with no PBD; P < 0·001), piperacillin-tazobactam (30·1 versus 0 per cent respectively; P = 0·003), ciprofloxacin (28·5 versus 5 per cent; P = 0·047) and imipenem (26·6 versus 0 per cent; P = 0·011). The rate of wound infection was higher in patients with a positive bile culture (21·0 per cent versus 6 per cent in patients with sterile bile; P = 0·002). Regression analysis revealed the presence of Enterococcus faecium (odds ratio 2·83, 95 per cent c.i. 1·17 to 6·84; P = 0·021) and Citrobacter species (odds ratio 5·09, 1·65 to 15·71; P = 0·005) as independent risk factors for postoperative wound infection. CONCLUSION: There are fundamental differences in the biliary microbiome of patients with periampullary cancer who undergo PBD and those who do not. PBD induces a shift of the biliary microbiome towards a more aggressive and resistant spectrum, which requires a differentiated perioperative antibiotic treatment strategy.


Subject(s)
Bile/microbiology , Common Bile Duct Neoplasms/complications , Drainage , Jaundice, Obstructive/therapy , Microbiota , Preoperative Care , Aged , Ampulla of Vater/surgery , Anti-Bacterial Agents/therapeutic use , Cholangitis/epidemiology , Citrobacter/isolation & purification , Common Bile Duct Neoplasms/surgery , Drug Resistance, Multiple, Bacterial , Enterobacteriaceae Infections/epidemiology , Enterococcus faecalis/isolation & purification , Female , Germany/epidemiology , Gram-Positive Bacterial Infections/epidemiology , Humans , Jaundice, Obstructive/etiology , Male , Regression Analysis , Retrospective Studies , Risk Factors , Stents , Surgical Wound Infection/epidemiology
17.
Neuropathol Appl Neurobiol ; 43(4): 299-314, 2017 Jun.
Article in English | MEDLINE | ID: mdl-26918424

ABSTRACT

AIMS: Mesenchymal stem cells (MSC) have recently attracted interest as a potential basis for a cell-based therapy of AD. We investigated the putative immune-modulatory effects in neuroinflammation of systemic transplantation of MSC into APP/PS1 transgenic mice. METHODS: 106 MSC were injected into APP/PS1 mice via the tail vein and histological analysis was performed for microglia and amyloid (pE3-Aß) plaque numbers, glial distribution and pE3-Aß plaque size. In addition, a biochemical analysis by qPCR for pro-inflammatory, chemoattractant and neurotrophic factors was performed. RESULTS: MSC are associated with pE3-Aß plaques. The effects of transplantation on microglia-associated pathology could be observed after 28 days. Animals showed a reduction in microglial numbers in the cortex and in microglia size. Gene expression was reduced for TNF-α, IL-6, MCP-1, and for NGF, in MSC recipients. Also, we investigated for the first time and found no changes in expression of IL-10, CCR5, BDNF, VEGF and IFNγ. PTGER2 expression levels were increased in the hippocampus but were reduced in the cortex of MSC recipients. While there were no transplant-related changes in pE3-Aß plaque numbers, a reduction in the size of pE3-Aß plaques was observed in the hippocampus of transplant recipients. CONCLUSION: This is the first study to show reduction in pE3-Aß plaque size. pE3-Aß plaques have gained attention as potential key participants in AD due to their increased aggregation propensity, the possibility for the initial seeding event, resistance against degradation and neurotoxicity. These findings support the hypothesis that MSC-transplants may affect AD pathology via an immune-modulatory function that includes an effect on microglial cells.


Subject(s)
Alzheimer Disease/pathology , Brain/pathology , Mesenchymal Stem Cell Transplantation/methods , Plaque, Amyloid/pathology , Animals , Mice , Mice, Transgenic
18.
Solid State Nucl Magn Reson ; 79: 6-10, 2016 10.
Article in English | MEDLINE | ID: mdl-27750080

ABSTRACT

29Si{27Al} TRAPDOR MAS NMR was applied to two faujasite-type zeolites with Si/Al ratios of 1.3 (Na-X) and 2.7 (Na-Y). The aim of this test study is to show that different Q4(mAl) sites (m =4, 3, 2, 1) can be distinguished by differently strong TRAPDOR effects (ΔS/S0). Indeed, it was found that the TRAPDOR effect depends on the number m of AlO4 units connected to the Q4 silicon tetrahedrons. For Na-X, the measured ΔS/S0 values are 1 : 0.81 : 0.56 for Q4(4Al), Q4(3Al) and Q4(2Al), respectively (normalized to Q4(4Al)). The corresponding ΔS/S0 values are the same for Na-Y within the error bars, although the silicon sites are different: Q4(3Al), Q4(2Al) and Q4(1Al) and now normalized to Q4(3Al) as no Q4(4Al) is present. Nevertheless, the proposed method opens up the possibility to distinguish overlapping 29Si NMR signals of the Qn(mAl) sites in amorphous materials as the main goal of these investigations.

19.
Implement Sci ; 11(1): 123, 2016 09 13.
Article in English | MEDLINE | ID: mdl-27624776

ABSTRACT

BACKGROUND: Although there is evidence that tailored implementation strategies can be effective, there is little evidence on which methods of tailoring improve the effect. We designed and evaluated five tailored programs (TPs) each consisting of various strategies. The aim of this study was to examine (a) how determinants of practice prioritized in the design phase of the TPs were perceived by health care professionals who had been exposed to the TPs and whether they suggested other important determinants of practice and (b) how professionals used the offered strategies and whether they suggested other strategies that might have been more effective. METHODS: We conducted a mixed-method process evaluation linked to five cluster-randomized trials carried out in five European countries to implement recommendations for five chronic conditions in primary care settings. The five TPs used a total of 28 strategies which aimed to address 38 determinants of practice. Interviews of professionals in the intervention groups and a survey of professionals in the intervention and control groups were performed. Data collection was conducted by each research team in the respective national language. The interview data were first analyzed inductively by each research team, and subsequently, a meta-synthesis was conducted. The survey was analyzed descriptively. RESULTS: We conducted 71 interviews; 125 professionals completed the survey. The survey showed that 76 % (n = 29) of targeted determinants of practice were perceived as relevant and 95 % (n = 36) as being modified by the implementation interventions by 66 to 100 % of professionals. On average, 47 % of professionals reported using the strategies and 51 % considered them helpful, albeit with substantial variance between countries and strategies. In the interviews, 89 determinants of practice were identified, of which 70 % (n = 62) had been identified and 45 % (n = 40) had been prioritized in the design phase. The interviewees suggested 65 additional strategies, of which 54 % (n = 35) had been identified and 20 % (n = 13) had been prioritized, but not selected in the final programs. CONCLUSIONS: This study largely confirmed the perceived relevance of the targeted determinants of practice. This contrasts with the fact that no impact of the trials on the implementation of the recommendations could be observed. The findings suggest that better methods for prioritization of determinants and strategies are needed. TRIAL REGISTRATION: Each of the five trials was registered separately in recognized trial registries. Details are given in the respective trial outcome papers.


Subject(s)
Chronic Disease/therapy , Evidence-Based Medicine/methods , Outcome and Process Assessment, Health Care/methods , Primary Health Care/methods , Program Evaluation/methods , Adult , Aged , Cluster Analysis , Europe , Female , Humans , Male , Middle Aged , Socioeconomic Factors , Young Adult
20.
Neurobiol Dis ; 89: 112-25, 2016 May.
Article in English | MEDLINE | ID: mdl-26836693

ABSTRACT

The oncogene DJ-1 has been originally identified as a suppressor of PTEN. Further on, loss-of-function mutations have been described as a causative factor in Parkinson's disease (PD). DJ-1 has an important function in cellular antioxidant responses, but its role in central metabolism of neurons is still elusive. We applied stable isotope assisted metabolic profiling to investigate the effect of a functional loss of DJ-1 and show that DJ-1 deficient neuronal cells exhibit decreased glutamine influx and reduced serine biosynthesis. By providing precursors for GSH synthesis, these two metabolic pathways are important contributors to cellular antioxidant response. Down-regulation of these pathways, as a result of loss of DJ-1 leads to an impaired antioxidant response. Furthermore, DJ-1 deficient mouse microglia showed a weak but constitutive pro-inflammatory activation. The combined effects of altered central metabolism and constitutive activation of glia cells raise the susceptibility of dopaminergic neurons towards degeneration in patients harboring mutated DJ-1. Our work reveals metabolic alterations leading to increased cellular instability and identifies potential new intervention points that can further be studied in the light of novel translational medicine approaches.


Subject(s)
Antioxidants/metabolism , Glutamine/metabolism , Neurons/metabolism , Protein Deglycase DJ-1/metabolism , Serine/metabolism , Animals , Cells, Cultured , Humans , Metabolome , Mice , Microglia/metabolism , Mitochondria/metabolism , Oxidative Stress , Protein Deglycase DJ-1/genetics
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