Zur Synthese von 6[18F]Fluor-L-DOPA durch nukleophile 18F-Fluorierung Carbonyl-aktivierter aromatischer Aminosäurederivate

6-[$^{18}$F]Fluoro-L-3,4-dihydroxyphenylalanine (6-[$^{18}$F]fluoro-L-DOPA), an analogue of L-DOPA, is an established radiotracer for diagnostic PET-studies of the integrity and function of the nigrostriatal dopaminergic system. The use of this important compound in clinical centers is mainly limited by the lack of a nucleophilic radiofluorination method of preparation using the advantage of large scale production of [$^{18}$F]fluoride. In this work a new convenient nucleophilic labelling method using [$^{18}$F]fluoride has been developed. With regard to the synthesis of 6-[$^{18}$F]fluoro-L-DOPA via nucleophilic $^{18}$F-fluorination of carbonylactivated aromatic amino acid derivatives, several O-protected 4-fluoro-2-hydroxy-5-methylbenzaldehydes were prepared as model compounds in order to evaluate the concept of synthesis. The 2-benzyloxy-4-[$^{18}$F]fluoro-5-methyl-benzaldehyde was prepared via $^{18}$F-for-$^{19}$F substitution with a radiochemical yield of 85 ± 5 % and via $^{18}$F-for-N(CH$_{3}$)$_{3}$ substitution on (5-benzyloxy-4-formyl-2-methyl-phenyl)-trimethylammoniumtriflate with a radiochemical yield of 92 ± 5 %. Thereof the synthesis of n.c.a. 2-benzyloxy-4-[$^{18}$]fluoro-5-methyl-phenol was achieved by Baeyer-Villiger oxidation with m-chloroperbenzoic acid with an overall radiochemical yield of 54 ± 5 %within 40 minutes. An appropriate precursor for the synthesis of 6-[$^{18}$F]fluoro-L-DOPA was synthesized by electrophilic alkylation of the lithiated bis-lactim ether (R)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine with 4-benzyloxy-2-fluoro-benzylbromide. The corresponding 5-(4-benzyloxy-2-fluorobenzyl)-(2R,5S)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine, obtained with a diastereomeric excess of 84 %, was formylated in the aromatic 5-position with dichloromethyl methyl ether in the presence of a sixfold excess of tin(IV)chloride. The nucleophilic $^{18}$F-fluorination of 5-(4-benzyloxy-2-fluoro-5-formyl-benzyl)-(2R,5S)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine was performed in DMF at 130 °C in the presence of the common Kryptofix 222/potassium carbonate system for 3 minutes. The radiochemical yield of the isotopic exchange was about 30 ± 5 %. Baeyer-Villiger oxidation of 5-(4-benzyloxy-2-[$^{18}$F]fluoro-5-formyl-benzyl)-(2R,5S)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine to the corresponding formiate with m-chloroperbenzoic acid and subsequent hydrolysis and deprotection under strong acidic conditions led to the formation of c.a. 6-[$^{18}$F]fiuoro-DOPA with an enantiomeric excess of the L-isomer of about 70 %. The overail radiochemical yield of 6-[$^{18}$F]fluoro-L-DOPA was 14 to 18 % within 70 minutes. According to the amount of 11 $\mu$mol precursor the carrier content is lower by a factor of about 10 in comparison to the electrophilic $^{18}$F-fluorination methods commonly used. Furthermore, use can be made of the fivefold higher production of [$^{18}$F]fluoride compared to [$^{18}$F]F$_{2}$. However, the racemic mixture of 6-[$^{18}$F]fluoro-L-DOPA still requires a chiral HPLC separation

Na rzece czasu. O wspomnieniach Zofii Kozarynowej „Sto lat. Gawęda o kulturze środowiska”

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CpG Island Methylation in Human Lymphocytes Is Highly Correlated with DNA Sequence, Repeats, and Predicted DNA Structure

CpG island methylation plays an important role in epigenetic gene control during mammalian development and is frequently altered in disease situations such as cancer. The majority of CpG islands is normally unmethylated, but a sizeable fraction is prone to become methylated in various cell types and pathological situations. The goal of this study is to show that a computational epigenetics approach can discriminate between CpG islands that are prone to methylation from those that remain unmethylated. We develop a bioinformatics scoring and prediction method on the basis of a set of 1,184 DNA attributes, which refer to sequence, repeats, predicted structure, CpG islands, genes, predicted binding sites, conservation, and single nucleotide polymorphisms. These attributes are scored on 132 CpG islands across the entire human Chromosome 21, whose methylation status was previously established for normal human lymphocytes. Our results show that three groups of DNA attributes, namely certain sequence patterns, specific DNA repeats, and a particular DNA structure, are each highly correlated with CpG island methylation (correlation coefficients of 0.64, 0.66, and 0.49, respectively). We predicted, and subsequently experimentally examined 12 CpG islands from human Chromosome 21 with unknown methylation patterns and found more than 90% of our predictions to be correct. In addition, we applied our prediction method to analyzing Human Epigenome Project methylation data on human Chromosome 6 and again observed high prediction accuracy. In summary, our results suggest that DNA composition of CpG islands (sequence, repeats, and structure) plays a significant role in predisposing CpG islands for DNA methylation. This finding may have a strong impact on our understanding of changes in CpG island methylation in development and disease

The nudibranch Berghia stephanieae (Valdés, 2005) is not able to initiate a functional symbiosome-like environment to maintain Breviolum minutum (J.E.Parkinson & LaJeunesse 2018)

Photosymbiosis is found in different animal lineages and is best understood in cnidarians. A successful initiation and maintenance of the symbiosis between the animal hosts and the photosymbiotic partners is based on a recognition by specific host receptors. This triggers signaling cascades that promote the photobiont tolerance by the host, including an interpartner nutrient exchange and the ability of the host to cope with increased levels of reactive oxygen species (ROS) generated by the photobiont. Key to the successful symbiosis is the inhibition of the phagosomal maturation resulting in the formation of the symbiosome. In animals other than cnidarians, little is known about the photosymbiosis initiation and maintenance, for instance in sea slugs belonging to the Nudibranchia. Here, we investigated the gene expression profile of Berghia stephanieae, which is able to incorporate Breviolum minutum from its cnidarian prey Exaiptasia diaphana (Rapp, 1829) but is not able to maintain the algae for more than a couple of days during starvation. We show that the recognition of the algae is based on similar mechanisms present in cnidarians, and we identified some additional candidate genes that might be molluscan specific for photobiont recognition. Downstream, B. stephanieae responds to increased levels of ROS but is not able to stop the phagosomal maturation or decrease the immune response against B. minutum, which seem to be the key factors missing in B. stephanieae that accounts for the unstable symbiosis in this slug. Hence, B. stephanieae can be considered a transitional state toward a stable photosymbiosis and can help to elucidate general aspects of the evolutionary processes involved in establishing photosymbioses in animals

Promiscuous gene expression in thymic epithelial cells is regulated at multiple levels

The role of central tolerance induction has recently been revised after the discovery of promiscuous expression of tissue-restricted self-antigens in the thymus. The extent of tissue representation afforded by this mechanism and its cellular and molecular regulation are barely defined. Here we show that medullary thymic epithelial cells (mTECs) are specialized to express a highly diverse set of genes representing essentially all tissues of the body. Most, but not all, of these genes are induced in functionally mature CD80hi mTECs. Although the autoimmune regulator (Aire) is responsible for inducing a large portion of this gene pool, numerous tissue-restricted genes are also up-regulated in mature mTECs in the absence of Aire. Promiscuously expressed genes tend to colocalize in clusters in the genome. Analysis of a particular gene locus revealed expression of clustered genes to be contiguous within such a cluster and to encompass both Aire-dependent and –independent genes. A role for epigenetic regulation is furthermore implied by the selective loss of imprinting of the insulin-like growth factor 2 gene in mTECs. Our data document a remarkable cellular and molecular specialization of the thymic stroma in order to mimic the transcriptome of multiple peripheral tissues and, thus, maximize the scope of central self-tolerance

Custos versus Benefícios resultantes da Ação Coletiva na Agricultura Familiar: Um Olhar Além das Informações Financeiras

A literatura e as teorias que permeiam o desenvolvimento regional têm demonstrado que, além das percepções financeiras positivas e/ou negativas resultantes das ações coletivas, há custos e benefícios não financeiros, falhas e desafios a serem enfrentados pelos grupos. Diante disso, este estudo teve como objetivo central analisar de que forma a estrutura de governança coletiva apresenta influência (social, econômica, informacional, cultural e política) sobre os agricultores familiares associados à Associação de Produtores de Corumbataí do Sul – APROCOR. Para isso, foram utilizados os métodos qualitativo e explicativo, através da pesquisa documental e entrevistas. Os resultados demonstraram que, dentre os inúmeros benefícios gerados aos produtores familiares, destaca-se o papel da APROCOR em proporcionar ganhos econômicos e financeiros, informacionais, sociais, ambientais e de saúde ao trabalhador rural. Além dos benefícios gerados ao produtor, o estudo demonstrou ainda que a ação coletiva gera externalidades positivas, resultando em ganhos para a família do produtor rural, para o meio ambiente e comunidade local. As principais falhas existentes entre os indivíduos analisados incluem dificuldades de natureza cognitiva, estrutural, comportamental, institucional e política, além de desafios, dentre os quais, a capacitação dos agentes e promoção da racionalidade coletiva. Conclui-se que, apesar das falhas, há viabilidade da ação coletiva, uma vez que há possibilidade de minimização das dificuldades e cumprimento dos desafios coletivos

Evidências de validade de duas escalas relacionadas à Pedagogia do Esporte: desenvolvimento socioeducativo e de autonomia no esporte infantojuvenil

Competition is the essence of sports and, when conceived having participants as references, it can contributes to the development of different pedagogical contents, among them, socio-educative aspects and autonomy. The purpose of this research was to demonstrate the first validity evidences of two scales for supporting socio-educational and autonomy development in youth sports; both are part of the Battery of Tests Gonçalves-Balbinotti of Pedagogical Contents’ Development Support in Youth Sports. We aim to estimate their internal structures, test their stabilities and estimate their internal consistency. A sample of 210 coaches answered the scales related to socio-educational and autonomy development, which presented second order two-factor structures with significant factor loadings (> 0.40) and explaining 80.6% and 73.2% of the constructs’ total variance, respectively. The results related to the model fit were satisfactory (X2/df 0.95; RMSEA 0.95; TLI > 0.95). The results regarding the internal consistency (0.786 0,40) e explicando 80,6% e 73,2% da variância total dos construtos, respectivamente. Os resultados relacionados ao ajuste do modelo foram satisfatórios (X2 /df 0,95; RMSEA 0,95; TLI > 0,95). Os resultados relativos à consistência interna (0,786 < α < 0,913 para os fatores; αSE = 0,889; αAu = 0,870) asseguram a precisão das medidas e a fidedignidade dos seus usos de acordo com o proposto. Os resultados respondem aos objetivos geral e específicos da pesquisa e indicam o uso seguro destas duas escalas

DNA methylation biomarkers in colorectal cancer: Clinical applications for precision medicine

Colorectal cancer (CRC) is the second leading cause of cancer death worldwide that is attributed to gradual long-term accumulation of both genetic and epigenetic changes. To reduce the mortality rate of CRC and to improve treatment efficacy, it will be important to develop accurate noninvasive diagnostic tests for screening, acute and personalized diagnosis. Epigenetic changes such as DNA methylation play an important role in the development and progression of CRC. Over the last decade, a panel of DNA methylation markers has been reported showing a high accuracy and reproducibility in various semi-invasive or noninvasive biosamples. Research to obtain comprehensive panels of markers allowing a highly sensitive and differentiating diagnosis of CRC is ongoing. Moreover, the epigenetic alterations for cancer therapy, as a precision medicine strategy will increase their therapeutic potential over time. Here, we discuss the current state of DNA methylation-based biomarkers and their impact on CRC diagnosis. We emphasize the need to further identify and stratify methylation-biomarkers and to develop robust and effective detection methods that are applicable for a routine clinical setting of CRC diagnostics particularly at the early stage of the disease

Psychopathology and cognition in children with 22q11.2 deletion syndrome

BACKGROUND: Children with 22q11.2 deletion syndrome (22q11.2DS) have been reported to have high rates of cognitive and psychiatric problems. AIMS: To establish the nature and prevalence of psychiatric disorder and neurocognitive impairment in children with 22q11.2DS and test whether risk of psychopathology is mediated by the children's intellectual impairment. METHOD: Neurocognition and psychopathology were assessed in 80 children with 22q11.2DS (mean age 10.2 years, s.d. = 2.1) and 39 sibling controls (mean age 10.9 years, s.d. = 2.0). RESULTS: More than half (54 of children with 22q11.2DS met diagnostic criteria for one or more DSM-IV-TR psychiatric disorder. These children had lower IQ (mean 76.8, s.d. = 13.0) than controls (mean 108.6, s.d. = 15.2) (