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1.
Soft Matter ; 20(26): 5134-5152, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38895755

RESUMO

This study presents a rigorous mechanical characterisation investigation on milk chocolate with varying porosities, at different temperatures and strain rate levels. Uniaxial compression tests at temperatures varying from 20 °C to 30 °C were performed to measure the bulk properties of chocolate as a function of porosity and temperature. Fracture experiments were also conducted to compute the fracture energy at temperature levels between 20 °C and 30 °C for all tested samples. Additionally, rheological experiments are conducted to compute the viscosity of the different chocolates at 37 °C. This combined experimental analysis of solid mechanics, fracture mechanics, and rheology aims to define the impact of temperature and chocolate's phase change from solid to liquid on its mechanical properties. Moreover, the impact of micro-aeration on the relationship between material properties and temperature is discussed. The results demonstrate a significant impact of both temperature and micro-aeration on the chocolate's material properties; fracture stresses decrease with micro-aeration due to the presence of micro-pores creating weak links in the chocolate matrix, the critical strain energy release rate decreases with micro-aeration at temperatures up to 25 °C and increases at temperatures above 30 °C. Finally, the viscosity at 37 °C increases with increasing porosity due to the obstruction of the flow by micro-pores acting as "solid" particles. The results highlight how the impact of micro-aeration on the material properties of chocolate alters as the testing temperature rises and the material changes phase. The relationships between the micro-aeration and material properties and the dependence of temperature on the different mechanical properties are used to explain the difference in textural attributes as obtained from temporal dominance sensation tests. This study seeks to contribute valuable insights into the field of chocolate technology, emphasizing the need for a combined engineering approach to understand the structural breakdown of chocolate during oral processing as mechanisms such as chewing, melting, mixing and shearing occur.


Assuntos
Chocolate , Reologia , Temperatura , Viscosidade , Porosidade
2.
Nervenarzt ; 94(10): 934-943, 2023 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-37140605

RESUMO

BACKGROUND: Malignant middle cerebral artery infarction is a potentially life-threatening disease. Decompressive hemicraniectomy constitutes an evidence-based treatment practice, especially in patients under 60 years of age; however, recommendations with respect to postoperative management and particularly duration of postoperative sedation lack standardization. OBJECTIVE: This survey study aimed to analyze the current situation of patients with malignant middle cerebral artery infarction following hemicraniectomy in the neurointensive care setting. MATERIAL AND METHODS: From 20 September 2021 to 31 October 2021, 43 members of the initiative of German neurointensive trial engagement (IGNITE) network were invited to participate in a standardized anonymous online survey. Descriptive data analysis was performed. RESULTS: Out of 43 centers 29 (67.4%) participated in the survey, including 24 university hospitals. Of the hospitals 21 have their own neurological intensive care unit. While 23.1% favored a standardized approach regarding postoperative sedation, the majority utilized individual criteria (e.g., intracranial pressure increase, weaning parameters, complications) to assess the need and duration. The timing of targeted extubation varied widely between hospitals (≤ 24 h 19.2%, ≤ 3 days in 30.8%, ≤ 5 days in 19.2%, > 5 days in 15.4%). Early tracheotomy (≤ 7 days) is performed in 19.2% and 80.8% of the centers aim for tracheotomy within 14 days. Hyperosmolar treatment is used on a regular basis in 53.9% and 22 centers (84.6%) agreed to participate in a clinical trial addressing the duration of postoperative sedation and ventilation. CONCLUSION: The results of this nationwide survey among neurointensive care units in Germany reflect a remarkable heterogeneity in the treatment practices of patients with malignant middle cerebral artery infarction undergoing hemicraniectomy, especially with respect to the duration of postoperative sedation and ventilation. A randomized trial in this matter seems warranted.


Assuntos
Craniectomia Descompressiva , Infarto da Artéria Cerebral Média , Humanos , Infarto da Artéria Cerebral Média/cirurgia , Craniectomia Descompressiva/métodos , Inquéritos e Questionários , Hospitais Universitários , Traqueotomia , Resultado do Tratamento
3.
Faraday Discuss ; 239(0): 130-145, 2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-35843221

RESUMO

The interface formation and chemical and electronic structure of the (Cd,Zn)S:Ga/CuSbS2 thin-film solar cell heterojunction were studied using hard X-ray photoelectron spectroscopy (HAXPES) of the bare absorber and a buffer/absorber sample set for which the buffer thickness was varied between 1 and 50 nm. We find a heavily intermixed interface, involving Cu, Zn, and Cd as well as significant Ga and Cu profiles in the buffer. The valence band (VB) offset at the buffer/absorber interface was derived as (-1.3 ± 0.1) eV, which must be considered an upper bound as the Cu diffused into the buffer might form a Cu-derived VB maximum located closer to the Fermi level. The estimated conduction band minimum was 'cliff'-like; a situation made more severe considering the Cu-deficiency found for the CuSbS2 surface. The complex interface structure's effect on the performance of (Cd,Zn)S:Ga/CuSbS2-based solar cells and its limitation is discussed together with possible mitigation strategies.

4.
Neuropathol Appl Neurobiol ; 46(5): 422-430, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-31867747

RESUMO

AIMS: DNA methylation-based central nervous system (CNS) tumour classification has identified numerous molecularly distinct tumour types, and clinically relevant subgroups among known CNS tumour entities that were previously thought to represent homogeneous diseases. Our study aimed at characterizing a novel, molecularly defined variant of glioneuronal CNS tumour. PATIENTS AND METHODS: DNA methylation profiling was performed using the Infinium MethylationEPIC or 450 k BeadChip arrays (Illumina) and analysed using the 'conumee' package in R computing environment. Additional gene panel sequencing was also performed. Tumour samples were collected at the German Cancer Research Centre (DKFZ) and provided by multinational collaborators. Histological sections were also collected and independently reviewed. RESULTS: Genome-wide DNA methylation data from >25 000 CNS tumours were screened for clusters separated from established DNA methylation classes, revealing a novel group comprising 31 tumours, mainly found in paediatric patients. This DNA methylation-defined variant of low-grade CNS tumours with glioneuronal differentiation displays recurrent monosomy 14, nuclear clusters within a morphology that is otherwise reminiscent of oligodendroglioma and other established entities with clear cell histology, and a lack of genetic alterations commonly observed in other (paediatric) glioneuronal entities. CONCLUSIONS: DNA methylation-based tumour classification is an objective method of assessing tumour origins, which may aid in diagnosis, especially for atypical cases. With increasing sample size, methylation analysis allows for the identification of rare, putative new tumour entities, which are currently not recognized by the WHO classification. Our study revealed the existence of a DNA methylation-defined class of low-grade glioneuronal tumours with recurrent monosomy 14, oligodendroglioma-like features and nuclear clusters.


Assuntos
Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/patologia , Cromossomos Humanos Par 14/genética , Glioma/genética , Glioma/patologia , Metilação de DNA , Feminino , Humanos , Masculino , Monossomia , Neurocitoma/genética , Neurocitoma/patologia , Oligodendroglioma/genética , Oligodendroglioma/patologia
5.
Clin Genet ; 94(1): 185-186, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29498415

RESUMO

Ataxia-oculomotor apraxia type 4 (AOA4) is a rare autosomal recessive neurologic disorder. The phenotype is characterized by ataxia, oculomotor apraxia, peripheral neuropathy and dystonia. AOA4 is caused by biallelic pathogenic variants in the PNKP gene encoding a polynucleotide kinase 3'-phosphatase with an important function in DNA-damage repair. By whole exome sequencing, we identified 2 variants within the PNKP gene in a 27-year-old German woman with a clinical AOA phenotype combined with a cerebellar pilocytic astrocytoma diagnosed at 23 years of age. One variant, a duplication in exon 14 resulting in the frameshift c.1253_1269dup p.(Thr424fs*49), has previously been described as pathogenic, for example, in cases of AOA4. The second variant, representing a nonsense mutation in exon 17, c.1545C>G p.(Tyr515*), has not yet been described and is predicted to cause a loss of the 7 C-terminal amino acids. This is the first description of AOA4 in a patient with central European descent. Furthermore, the occurrence of a pilocytic astrocytoma has not been described before in an AOA4 patient. Our data demonstrate compound heterozygous PNKP germline variants in a German patient with AOA4 and provide evidence for a possible link with tumor predisposition. Localization of the 2 variants in human PNKP NP_009185.2. NM_007254.3:c.1253_1269dup p.(Thr424fs*49) is predicted to cause a frameshift within the kinase domain, NM_007254.3:c.1545C>G p.(Tyr515*) is predicted to cause loss of 2 C-terminal amino acids of the kinase domain and 5 additional C-terminal amino acids.


Assuntos
Apraxias/congênito , Astrocitoma/genética , Síndrome de Cogan/genética , Enzimas Reparadoras do DNA/genética , Sequenciamento do Exoma , Heterozigoto , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Alelos , Sequência de Aminoácidos , Apraxias/diagnóstico , Apraxias/genética , Astrocitoma/diagnóstico , Síndrome de Cogan/diagnóstico , Dano ao DNA , Enzimas Reparadoras do DNA/química , Éxons , Feminino , Humanos , Mutação , Linhagem , Fosfotransferases (Aceptor do Grupo Álcool)/química
6.
Am J Transplant ; 17(8): 2200-2206, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28452107

RESUMO

In summer 2015, three unrelated solid organ transplant recipients in Phoenix, Arizona, had meningoencephalitis suggestive of West Nile virus (WNV) infection. Testing was inconclusive but was later confirmed as St. Louis encephalitis (SLE). We retrospectively reviewed clinical manifestations, treatment, and outcomes of these transplant recipients. Common symptoms were fever, rigors, diarrhea, headache, and confusion. One patient died 3 days after hospitalization. Therapy for the other two patients was initiated with interferon α-2b (IFN) and intravenous IgG (IVIG; IFN plus IVIG in combination). Both patients tested positive for WNV by serologic assay, but SLE virus (SLEV) infection was later confirmed by plaque reduction neutralization test at a reference laboratory. Clinical improvement was observed within 72 h after initiation of IFN plus IVIG. SLEV has been an uncommon cause of neuroinvasive disease in the United States. Accurate, timely diagnosis is hindered because of clinical presentation similar to neuroinvasive WNV and SLE, serologic cross-reactivity, and lack of a commercially available serologic assay for SLEV. There is currently no approved therapy for flaviviral neuroinvasive disease. Anecdotal reports indicate varying success with IFN, IVIG, or IFN plus IVIG in WNV neuroinvasive disease. The same regimen might be of value for immunocompromised persons with neuroinvasive SLEV infection.


Assuntos
Antivirais/uso terapêutico , Surtos de Doenças , Vírus da Encefalite de St. Louis/efeitos dos fármacos , Encefalite de St. Louis/epidemiologia , Sobrevivência de Enxerto/efeitos dos fármacos , Transplante de Órgãos , Idoso , Anticorpos Antivirais/sangue , Encefalite de St. Louis/tratamento farmacológico , Encefalite de St. Louis/virologia , Seguimentos , Humanos , Imunoglobulinas Intravenosas/administração & dosagem , Interferon-alfa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Prevalência , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Transplantados , Estados Unidos/epidemiologia
7.
J Chem Phys ; 146(24): 244112, 2017 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-28668056

RESUMO

The sensitivity of molecular dynamics on changes in the potential energy function plays an important role in understanding the dynamics and function of complex molecules. We present a method to obtain path ensemble averages of a perturbed dynamics from a set of paths generated by a reference dynamics. It is based on the concept of path probability measure and the Girsanov theorem, a result from stochastic analysis to estimate a change of measure of a path ensemble. Since Markov state models (MSMs) of the molecular dynamics can be formulated as a combined phase-space and path ensemble average, the method can be extended to reweight MSMs by combining it with a reweighting of the Boltzmann distribution. We demonstrate how to efficiently implement the Girsanov reweighting in a molecular dynamics simulation program by calculating parts of the reweighting factor "on the fly" during the simulation, and we benchmark the method on test systems ranging from a two-dimensional diffusion process and an artificial many-body system to alanine dipeptide and valine dipeptide in implicit and explicit water. The method can be used to study the sensitivity of molecular dynamics on external perturbations as well as to reweight trajectories generated by enhanced sampling schemes to the original dynamics.

8.
Eur J Clin Microbiol Infect Dis ; 35(8): 1309-13, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27177753

RESUMO

In this prospective and monocentric study, we investigated the performance of a commercialized real-time polymerase chain reaction (RT-PCR) test system for the specific detection of DNA from Candida albicans, C. dubliniensis, C. glabrata, C. krusei, C. lusitaniae, C. parapsilosis, and C. tropicalis in human milk samples of patients suspicious of mammary candidiasis. For this purpose, 43 breast-feeding women with characteristic symptoms of mammary candidiasis and 40 asymptomatic controls were enrolled. By culture, Candida spp. were detected in 8.8 % (4/46) and 9.3 % (4/43) of patient and control samples, respectively. Candida albicans (2/46), C. parapsilosis (1/46), and C. guilliermondii (1/46) were present in patient samples, and C. lusitaniae (3/43) and C. guilliermondii (1/43) were present in the controls. After RT-PCR was applied, Candida spp. were found to be present in 67.4 % (31/46) and 79.1 % (34/43) of patient and control samples investigated, respectively. PCR detection of C. albicans and C. parapsilosis revealed only a low sensitivity and specificity of 67.4 % and 41.9 %, respectively. Our data do not support the use of Candida RT-PCR for sensitive and specific diagnosis of mammary candidiasis.


Assuntos
Doenças Mamárias/microbiologia , Candida/genética , Candidíase/microbiologia , Leite Humano/microbiologia , Tipagem Molecular/métodos , Adolescente , Adulto , Bactérias/genética , DNA Bacteriano/análise , DNA Bacteriano/genética , DNA Fúngico/análise , DNA Fúngico/genética , Feminino , Humanos , Reação em Cadeia da Polimerase , Estudos Prospectivos , Adulto Jovem
9.
J Neurooncol ; 117(1): 25-32, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24395351

RESUMO

There is a lack of relevant prognostic and predictive factors in neurooncology besides mutation of isocitrate dehydrogenase 1, codeletion of 1p/19q and promoter hypermethylation of O (6) -methylguanine-DNA-methyltransferase. More importantly, there is limited translation of these factors into clinical practice. The cancer genome atlas data and also clinical correlative analyses suggest a pivotal role for the epidermal growth factor receptor /protein kinase B/mammalian target of rapamycin (mTOR) pathway in both biology and the clinical course of gliomas. However, attempts to stratify gliomas by activating alterations in this pathway have failed thus far. The tumors of 40 patients with WHO grade II gliomas without immediate postoperative genotoxic treatment and known progression and survival status at a median follow-up of 12.2 years were analyzed for expression of the mTOR complex 2 downstream target N-myc downstream regulated gene (NDRG)1 using immunohistochemistry. Baseline characteristics for NDRG1 absent/low versus moderate/high patients were similar. Time to reintervention was significantly longer in the NDRG1 group (P = 0.026). NDRG1 may become a novel biomarker to guide the decision which WHO°II glioma patients may be followed without postsurgical intervention and which patients should receive genotoxic treatment early on. Validation of this hypothesis will be possible with the observational arm of the RTOG 9802 and the pretreatment step of the EORTC 22033/26032 trials.


Assuntos
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Glioma/diagnóstico , Glioma/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Adulto , Idoso , Astrocitoma/diagnóstico , Astrocitoma/metabolismo , Astrocitoma/patologia , Astrocitoma/terapia , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/terapia , Seguimentos , Glioma/patologia , Glioma/terapia , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Gradação de Tumores , Oligodendroglioma/diagnóstico , Oligodendroglioma/metabolismo , Oligodendroglioma/patologia , Oligodendroglioma/terapia , Prognóstico , Estudos Prospectivos , Retratamento , Análise de Sobrevida , Fatores de Tempo
10.
Methods ; 59(1): 20-31, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23110812

RESUMO

The diagnostic use of in vitro molecular assays can be limited by the lack of guidelines for collection, handling, stabilization and storage of patient specimens. One of the major goals of the EC funded project SPIDIA (www.spidia.eu) is to develop evidence-based quality guidelines for the pre-analytical phase of blood samples used for molecular testing which requires intracellular RNA analytes. To this end, a survey and a pan-European external quality assessment (EQA) were implemented. This report is the summary of the results of that trial. With the European Federation of Laboratory Medicine (EFLM) support, 124 applications for participation in the trial were received from 27 different European countries, and 102 laboratories actually participated in the trial. Each participating laboratory described their respective laboratory policies and practices as well as blood collection tubes typically used in performing this type of testing. The participating laboratories received two identical blood specimens: in an EDTA tubes (unstabilized blood; n=67) or in tubes designed specifically for the stabilization of intracellular RNA in blood (PAXgene® Blood RNA tubes; n=35). Laboratories were requested to perform RNA extraction according to the laboratory's own procedure as soon as possible upon receipt of the tubes for one tube and 24h after the first extraction for the second tube. Participants (n=93) returned the two extracted RNAs to SPIDIA facility for analysis, and provided details about the reagents and protocols they used for the extraction. At the SPIDIA facility responsible for coordinating the study, the survey data were classified, and the extracted RNA samples were evaluated for purity, yield, integrity, stability, and the presence of interfering substances affecting RT-qPCR assays. All participants received a report comparing the performance of the RNA they submitted to that of the other participants. All the results obtained by participants for each RNA quality parameter were classified as "in control", "warning", "out of control" and "missing" by consensus mean analysis. From the survey data, the most variable parameters were the volume of blood collected and the time and storage temperature between blood collection and RNA extraction. Analyzing the results of quality testing of submitted RNA samples we observed a data distribution of purity, yield, and presence of assay interference in agreement with expected values. The RNA Integrity Number (RIN) values distribution was, on the other hand, much wider than the optimal expected value, which led to an "in control" classification, even for partly degraded RNA samples. On the other hand, RIN values below 5 significantly correlated with a reduction of GAPDH expression levels. Furthermore, the distribution of the values of the four transcripts investigated (c-fos, IL-1ß, IL-8, and GAPDH) was wide and the RNA instability between samples separated by 24h were similar. Assuming the presence of at least two quality parameters "out of control" as an indication of a critical performance of the laboratory, 33% of the laboratories were included in this group. The results of this study will be the basis for implementing a second pan-European EQA and the results of both EQAs will be pooled and will provide the basis for the implementation of evidence-based guidelines for the pre-analytical phase of RNA analysis of blood samples.


Assuntos
Análise Química do Sangue/normas , Coleta de Amostras Sanguíneas/normas , RNA/sangue , RNA/isolamento & purificação , Europa (Continente) , Perfilação da Expressão Gênica/normas , Guias como Assunto , Humanos , Ensaio de Proficiência Laboratorial
11.
Z Gastroenterol ; 52(10): 1153-6, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25313626

RESUMO

Colonoscopy is the standard technique in the diagnosis and treatment of colorectal neoplasia, but small adenomas and even advanced lesions can be missed during the procedure. With large scale screening colonoscopy programs installed, information on quality of colonoscopy in primary care is essential, but scarcely available. Over a period of 45 months, we prospectively included all those patients in our study, who underwent major colonic surgery at our institution and who had undergone a colonoscopy within 42 days prior to the operation. 89 men and 100 women, median age 71 years, were included. The majority of these operations were performed for colorectal carcinoma (125), other malignant tumors (4), suspected malignancies (6) or large adenomas (14). The pathologist inspected the resected colonic segment, and we compared his findings with the colonoscopy report. Colonoscopies had been performed by 22 doctors in 13 institutions. Median length of the resected colonic segments was 20 cm (range 3 to 135 cm), total length was 41,21 metres. In 14 segments the pathologist identified 28 neoplastic lesions not described in the endoscopy report. Colonoscopy had missed 2 carcinomas, both in the right colon, and a 12 mm tubulo-villous adenoma with high-grade dysplasia. Another 25 tubular adenomas had been missed, 2 measuring 10 mm, 7 between 5 and 9 mm and 16 smaller than 5 mm. We conclude that primary care colonoscopy misses neoplastic lesions in a significant number of procedures. Most of the missed lesions in our high risk group of patients would have been of little clinical consequence. In a small, but clinically important number of cases, however, advanced adenomas and even colorectal carcinomas were missed by endoscopy.


Assuntos
Adenoma/patologia , Carcinoma/patologia , Colonoscopia/estatística & dados numéricos , Neoplasias Colorretais/patologia , Testes Diagnósticos de Rotina/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/cirurgia , Diagnóstico Diferencial , Reações Falso-Negativas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
12.
Neuroimage ; 68: 203-13, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23247184

RESUMO

Previous research suggests that oscillatory coupling between cortex, basal ganglia and muscles plays an important role in motor behavior. Furthermore, there is evidence that oscillatory coupling is altered in patients with movement disorders such as Parkinson's disease (PD). In this study, we performed simultaneous magnetoencephalography (MEG), local field potential (LFP) and electromyogram (EMG) recordings in PD patients selected for therapeutic subthalamic nucleus (STN) stimulation. Patients were recorded (i) after withdrawal of anti-parkinsonian medication (OFF) and (ii) after levodopa administration (ON). We analyzed STN-cortical and cortico-muscular coherence during static forearm contraction and repetitive hand movement in order to evaluate modulations of coherence by movement and medication. Based on previous results from studies investigating resting state coherence in PD patients, we selected primary motor cortex (M1) and superior temporal gyrus (STG) as regions of interest. We found beta coherence between M1 and STN to be suppressed by administration of levodopa. M1-muscular coherence was strongly reduced in the alpha and beta band during repetitive movement compared to static contraction, but was unaffected by administration of levodopa. Strong STG-STN but not STG-muscular coherence could be observed in the alpha band. Coherence with STG was modulated neither by movement nor by medication. Finally, we found both M1-STN and M1-muscular beta coherence to be negatively correlated with UPDRS akinesia and rigidity sub-scores in the OFF state. The present study provides new insights into the functional roles of STN-cortical and cortico-muscular coherence and their relationship to PD symptoms. The results indicate that STN-cortical and cortico-muscular coupling are correlated, but can be modulated independently. Moreover, they show differences in their frequency-specific topography. We conclude that they represent partly independent sub-loops within the motor system. Given their negative correlation with akinesia, neither can be considered "antikinetic".


Assuntos
Movimento/fisiologia , Músculo Esquelético/fisiologia , Doença de Parkinson/fisiopatologia , Núcleo Subtalâmico/fisiopatologia , Idoso , Antiparkinsonianos/uso terapêutico , Estimulação Encefálica Profunda , Eletromiografia , Feminino , Humanos , Levodopa/uso terapêutico , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/terapia
13.
Neuropathol Appl Neurobiol ; 39(7): 831-6, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23521081

RESUMO

AIMS: Combined deletion of the whole chromosomal arms 1p and 19q is a frequent event in oligodendroglial tumours. Recent identification of recurrent mutations in CIC on 19q and FUBP1 on 1p and their mutational patterns suggest a loss of function of the respective proteins. Surprisingly, oligoastrocytomas harbouring identical genetic characteristics regarding 1p/19q codeletion and frequent IDH1/2 mutations have been shown to carry CIC mutations in a significantly lower number of cases. The present study investigates whether epigenetic modification may result in silencing of CIC. METHODS: As IDH1/2 mutation-mediated DNA hypermethylation is a prominent feature of these tumours, we analysed a set of CIC wild-type oligoastrocytomas and other diffuse gliomas with regard to 1p/19q status for presence of CIC-associated CpG island methylation by methylation-specific PCR. RESULTS: Both methylation-specific PCR and subsequent bisulphite-sequencing of selected cases revealed an unmethylated status in all samples. CONCLUSION: Despite the hypermethylator phenotype in IDH1/2 mutant tumours and recent detection of gene silencing particularly on retained alleles in oligodendroglial tumours, hypermethylation of CIC-associated CpG islands does not provide an alternative mechanism of functional CIC protein abrogation.


Assuntos
Neoplasias Encefálicas/genética , Cromossomos Humanos Par 19 , Cromossomos Humanos Par 1 , Ilhas de CpG/genética , Metilação de DNA , Oligodendroglioma/genética , Neoplasias Encefálicas/patologia , Metilação de DNA/genética , Predisposição Genética para Doença , Humanos , Perda de Heterozigosidade/genética , Mutação/genética
14.
J Neurooncol ; 112(2): 173-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23358936

RESUMO

Isocitrate dehydrogenase (IDH) mutational testing is becoming increasingly important. For this, robust and reliable assays are needed. We tested the variation of results between six laboratories of testing for IDH mutations. Each laboratory received five unstained slides from 31 formalin-fixed paraffin-embedded (FFPE) glioma samples, and followed its own standard IDH diagnostic routine. All laboratories used immunohistochemistry (IHC) with an antibody against the most frequent IDH1 mutation (R132H) as a first step. Three laboratories then sequenced only IHC negative cases while the others sequenced all cases. Based on the overall analysis, 13 samples from 11 tumors had an R132H mutation and one tumor showed an R132G mutation. Results of IHC for IDH1 R132H mutations in all six laboratories were completely in agreement, and identified all R132H mutations. Upon sequencing the results of two laboratories deviated from those of the others. After a review of the entire diagnostic process, on repeat (blinded) testing one laboratory was completely in agreement with the overall result. A change in technique did only partially improve the results in the other laboratory. IHC for the IDH1 R132H mutation is very reliable and consistent across laboratories. IDH sequencing procedures yielded inconsistent results in 2 out of 6 laboratories. Quality assurance is pivotal before IDH testing is made part of clinical management of patients.


Assuntos
Neoplasias Encefálicas/diagnóstico , Glioma/diagnóstico , Isocitrato Desidrogenase/genética , Laboratórios/normas , Mutação/genética , Neoplasias Encefálicas/genética , DNA de Neoplasias/genética , Glioma/genética , Humanos , Técnicas Imunoenzimáticas , Isocitrato Desidrogenase/metabolismo , Inclusão em Parafina , Reação em Cadeia da Polimerase
15.
Food Funct ; 13(9): 4993-5010, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35393999

RESUMO

Thermal properties, such as thermal conductivity, specific heat capacity and latent heat, influence the melting and solidification of chocolate. The accurate prediction of these properties for micro-aerated chocolate products with varying levels of porosity ranging from 0% to 15% is beneficial for understanding and control of heat transfer mechanisms during chocolate manufacturing and food oral processing. The former process is important for the final quality of chocolate and the latter is associated with sensorial attributes, such as grittiness, melting time and flavour. This study proposes a novel multiscale finite element model to accurately predict the temporal and spatial evolution of temperature across chocolate samples. The model is evaluated via heat transfer experiments at temperatures varying from 16 °C to 45 °C. Both experimental and numerical results suggest that the rate of heat transfer within the micro-aerated chocolate is reduced by 7% when the 15% micro-aerated chocolate is compared to its solid counterpart. More specifically, on average, the thermal conductivity decreased by 20% and specific heat capacity increased by 10% for 15% micro-aeration, suggesting that micro-pores act as thermal barriers to heat flow. The latter trend is unexpected for porous materials and thus the presence of a third phase at the pore's interface is proposed which might store thermal energy leading to a delayed release to the chocolate system. The developed multiscale numerical model provides a design tool to create pore structures in chocolate with optimum melting or solidifying response.


Assuntos
Cacau , Chocolate , Chocolate/análise , Temperatura Alta , Temperatura , Condutividade Térmica
16.
Plant Biol (Stuttg) ; 24(5): 721-733, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35357064

RESUMO

Volatile isoprenoids regulate plant performance and atmospheric processes, and Amazon forests comprise the dominant source to the global atmosphere. Still, there is a poor understanding of how isoprenoid emission capacities vary in response to ecophysiological and environmental controls in Amazonian ecosystems. We measured isoprenoid emission capacities of three Amazonian hyperdominant tree species - Protium hebetatum, Eschweilera grandiflora, Eschweilera coriacea - across seasons and along a topographic and edaphic environmental gradient in the central Amazon. From wet to dry season, both photosynthesis and isoprene emission capacities strongly declined, while emissions increased among the heavier isoprenoids: monoterpenes and sesquiterpenes. Plasticity across habitats was most evident in P. hebetatum, which emitted sesquiterpenes only in the dry season, at rates that significantly increased along the hydro-topographic gradient from white sands (shallow root water access) to uplands (deep water table). We suggest that emission composition shifts are part of a plastic response to increasing abiotic stress (e.g. heat and drought) and reduced photosynthetic supply of substrates for isoprenoid synthesis. Our comprehensive measurements suggest that more emphasis should be placed on other isoprenoids, besides isoprene, in the context of abiotic stress responses. Shifting emission compositions have implications for atmospheric responses because of the strong variation in reactivity among isoprenoid compounds.


Assuntos
Terpenos , Árvores , Ecossistema , Florestas , Estações do Ano
17.
Neuroimage ; 55(3): 1159-68, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21122819

RESUMO

Neuronal oscillations are assumed to play a pivotal role in the pathophysiology of Parkinson's disease (PD). Neurons in the subthalamic nucleus (STN) generate oscillations which are coupled to rhythmic population activity both in other basal ganglia nuclei and cortical areas. In order to localize these cortical areas, we recorded local field potentials (LFPs) and magnetoencephalography (MEG) simultaneously in PD patients undergoing surgery for deep brain stimulation (DBS). Patients were withdrawn from antiparkinsonian medication and recorded at rest. We scanned the entire brain for oscillations coherent with LFPs recorded from the STN with a frequency domain beamformer. Coherent activity in the low (12-20 Hz) and high (20-35 Hz) beta range was found in the ipsilateral sensorimotor and the premotor cortex. Coherence in the alpha range (7-12 Hz) was observed at various locations in the ipsilateral temporal lobe. In a subset of subjects, the superior temporal gyrus consistently showed coherent alpha oscillations. Our findings provide new insights into patterns of frequency-specific functional connectivity between basal ganglia and cortex and suggest that simultaneous inter-regional interactions may be segregated in the frequency domain. Furthermore, they demonstrate that simultaneous MEG-LFP recordings are a powerful tool to study interactions between brain areas in PD patients undergoing surgery for DBS.


Assuntos
Córtex Cerebral/patologia , Doença de Parkinson/patologia , Núcleo Subtalâmico/patologia , Idoso , Ritmo alfa/fisiologia , Ritmo beta/fisiologia , Interpretação Estatística de Dados , Estimulação Encefálica Profunda , Eletrodos Implantados , Eletroencefalografia , Eletromiografia , Eletroculografia , Fenômenos Eletrofisiológicos , Potenciais Evocados/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Imageamento por Ressonância Magnética , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Procedimentos Neurocirúrgicos , Doença de Parkinson/terapia , Tomografia de Coerência Óptica , Tomografia Computadorizada por Raios X
18.
Br J Cancer ; 104(11): 1747-54, 2011 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-21559010

RESUMO

BACKGROUND: The clinical course of World Health Organisation grade II gliomas remains variable and their time point of transformation into a more malignant phenotype is unpredictable. Identification of biological markers that can predict prognosis in individual patients is of great clinical value. PROX1 is a transcription factor that has a critical role in the development of various organs. PROX1 has been ascribed both oncogenic and tumour suppressive functions in human cancers. We have recently shown that PROX1 may act as a diagnostic marker for high-grade gliomas. The aim of this study was to address the prognostic value of PROX1 in grade II gliomas. METHODS: A total of 116 samples were evaluated for the presence of PROX1 protein. The number of immunopositive cells was used as a variable in survival analysis, together with established prognostic factors for this patient group. RESULTS: Higher PROX1 protein was associated with poor outcome. In the multivariate analysis, PROX1 was identified as an independent factor for survival (P=0.024), together with the presence of mutated isocitrate dehydrogenase 1 R132H protein, and with combined losses of chromosomal arms 1p/19q in oligodendrocytic tumours. CONCLUSION: PROX1 is a novel predictor of survival for grade II gliomas.


Assuntos
Neoplasias Encefálicas/diagnóstico , Glioma/diagnóstico , Proteínas de Homeodomínio/metabolismo , Isocitrato Desidrogenase/análise , Isocitrato Desidrogenase/genética , Proteínas Supressoras de Tumor/metabolismo , Adulto , Biomarcadores Tumorais/análise , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Feminino , Glioma/mortalidade , Glioma/patologia , Humanos , Perda de Heterozigosidade , Masculino , Pessoa de Meia-Idade , Mutação , Prognóstico , Análise de Sobrevida
19.
J Nanosci Nanotechnol ; 11(10): 8775-81, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22400258

RESUMO

Molding of nano structures by injection molding leads to special requirements for the tools e.g., wear resistance and as low as possible release forces of the molded components. On the other hand it is not allowed to affect the replication precision. Physical vapor deposition is one of the promising technologies for applying coatings with adapted properties like high hardness, low roughness, low Young's modulus and less adhesion to the plastics melt. Although physical vapor deposition technology allows the deposition of films on micro structures without changing the structure significantly, film deposition on nano structures and small micro structures leads to a relevant change in surface topography. For this reason direct structuring of physical vapor deposition coatings might be beneficial. In this paper structuring was done using a picoseconds ultraviolet laser, Lumera Laser "Rapid," with a master oscillator power amplifier system at 355 nm. Two different coatings were deposited by magnetron sputter ion plating physical vapor deposition technology for laser structuring tests ((Cr, Al)N, (Cr, Al,Si)N). After deposition, the coatings were analyzed by common techniques regarding hardness, Young's modulus and morphology. The structures were analyzed by scanning electron microscopy. The results show a high potential for laser structuring of coatings deposited via physical vapor deposition. Linear structures with sizes between 400 nm and 10microm were realized.

20.
Clin Neuropathol ; 30(5): 217-30, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21955925

RESUMO

Isocitrate dehydrogenase 1 (IDH1) gene mutations, primarily of the R132H type, occur in approximately 60 - 90% of diffuse and anaplastic gliomas and secondary glioblastomas. IDH mutations in gliomas are associated with several clinically relevant parameters including patient age, histopathological diagnosis, combined 1p/19q deletion, TP53 mutation, MGMT promoter hypermethylation and patient survival. Therefore, testing of the IDH status is relevant for diagnostic and prognostic considerations in primary brain tumors. IDH status can be assessed by immunohistochemistry or DNA-based methods including gene sequencing in the routine setting. Here, we review the relevance of IDH testing in diffuse gliomas and present practical instructions including detailed descriptions of procedures and protocols for diagnostic IDH testing using immunohistochemistry (for both automated and manual staining) and gene sequencing. Our article may provide guidance for laboratories aiming at establishing IDH testing for diagnostic evaluation of primary brain tumors.


Assuntos
Neoplasias Encefálicas/diagnóstico , Glioma/diagnóstico , Isocitrato Desidrogenase , Neoplasias Encefálicas/genética , Testes Genéticos , Glioma/genética , Humanos , Isocitrato Desidrogenase/genética , Mutação
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