A Mosaic Approach in the study of the normative contexts of childhood

Wśród wielu perspektyw badania przestrzeni dzieciństwa na uwagę zasługuje interesujące poznawczo zagadnienie eksploracji tego fragmentu rzeczywistości społecznej, który nazywamy "dzieciństwem dzieciństwa". Interesujące studia na ten temat zaprezentowała Alison Clark, nazywając je podejściem mozaikowym (the Mosaic Approach). Owo oryginalne podejście badawcze opiera się na dowartościowaniu kompetencji dzieci przeżywających swoje dzieciństwo, będących głównymi podmiotami, dzięki którym "dorosły" badacz pozyskuje wiarygodne źródło informacji. Dzieci postrzegane są jako eksperci ich własnego życia. To dzięki nim otrzymujemy wiedzę o tym, jakie znaczenia, wartości oraz doświadczenia życia codziennego budują przestrzeń ich dzieciństwa. W tej strategii badawczej szczególnego znaczenia nabiera aktywne słuchanie i proces rozumienia dzieci poprzez wszystkie dostępne ich wytwory. Poniższy artykuł przedstawia ujęcie teoretyczne proponowane przez A. Clark, które wykorzystała ona w procesie poszukiwań znaczeń, jakie dzieci w wieku przedszkolnym nadają prawu pozytywnemu współtworzącemu przestrzeń ich dzieciństwa.Among the many research perspectives in the exploration of childhood space, the attention of the researcher should be drawn to a cognitively interesting approach to the question of studying this fragment of social reality, which is called "the childhood of the childhood", namely the one which was presented by Alison Clark and defined as the Mosaic Approach. This original research strategy is based on the appreciation of the competences of children who experience their childhood as the main subjects through which an "adult" researcher acquires a reliable source of information. Children are experts in their own lives. It is thanks to them that we obtain knowledge about what meanings, values and experiences of everyday life build the space of their childhood. In this research strategy, active listening and the process of understanding children through the analysis of many available children’s products become particularly important. The following article presents the theoretical approach proposed by A. Clark used in the search for meanings that preschool children give to a positive law co-creating the space of their childhood

The miR396–GRF Regulatory Module Controls the Embryogenic Response in Arabidopsis via an Auxin-Related Pathway

In plants, microRNAs have been indicated to control various developmental processes, including somatic embryogenesis (SE), which is triggered in the in vitro cultured somatic cells of plants. Although a transcriptomic analysis has indicated that numerous MIRNAs are di erentially expressed in the SE of di erent plants, the role of specific miRNAs in the embryogenic reprogramming of the somatic cell transcriptome is still poorly understood. In this study, we focused on performing a functional analysis of miR396 in SE given that the transcripts of MIR396 genes and the mature molecules of miR396 were found to be increased during an SE culture of Arabidopsis. In terms of miR396 in embryogenic induction, we observed the SE-associated expression pattern of MIR396b in explants of the -glucuronidase (GUS) reporter line. In order to gain insight into the miR396-controlled mechanism that is involved in SE induction, the embryogenic response of mir396 mutants and the 35S:MIR396b overexpressor line to media with di erent 2,4-Dichlorophenoxyacetic acid (2,4-D) concentrations was evaluated. The results suggested that miR396 might contribute to SE induction by controlling the sensitivity of tissues to auxin treatment. Within the targets of miR396 that are associated with SE induction, we identified genes encoding the GROWTH-REGULATING FACTOR (GRF) transcription factors, including GRF1, GRF4, GRF7, GRF8, and GRF9. Moreover, the study suggested a regulatory relationship between miR396, GRF, and the PLETHORA (PLT1 and PLT2) genes during SE induction. A complex regulatory relationship within the miR396–GRF1/4/8/9–PLT1/2 module that involves the negative and positive control of GRFs and PLT (respectively) by miR396 might be assumed

Optimization of Western blotting analysis for the isolation and detection of membrane xenobiotic transporter ABCG2

All organisms are exposed to numerous stress factors, which include harmful xenobiotics. The diversity of these compounds is enormous, thus in the course of evolution diverse biological defense mechanisms at various levels of organization have developed. One of them engages an evolutionarily conserved family of transporters from the ABC superfamily, found in most species - from bacteria to humans. An important example of such a transporter is the breast cancer resistance protein (BCRP/ABCG2), a typical integral membrane protein. It plays a key role in the absorption, distribution and elimination of a wide variety of xenobiotics, including drugs used in chemotherapy, and is involved in multidrug resistance. It also protects against phototoxic chlorophyll derivatives of dietary origin. BCRP is a hemitransporter which consists of one transmembrane domain, made of six alpha-helices forming a characteristic pore structure, and one ATP-binding domain, which provides the energy from ATP hydrolysis, required for active transport of the substrates. The isolation of BCRP is still not an easy task, because its insolubility in water and the presence of membrane rafts pose serious methodological and technical challenges during the purification. The aim of this study was to optimize the methods for detection and isolation of BCRP-enriched fractions obtained from animal tissue samples. In this report we describe an optimization of isolation of a BCRP-enriched membrane fraction, which is suitable for further protein quantitative and qualitative analysis using the molecular biology tools

Rola wybranych składników odżywczych we wspomaganiu leczenia farmakologicznego choroby Alzheimera

Choroba Alzheimera (AD, Alzheimer’s disease) jest najczęstszą, postępującą chorobą neurodegeneracyjną, charakteryzującą się utratą pamięci i utratą zdolności do samodzielnego życia u osób w podeszłym wieku. W mechanizmie choroby podstawową rolę odgrywa niedobór acetylocholiny oraz upośledzenie przekaźnictwa cholinergicznego. Na podstawie badań przedklinicznych, w których wykazano, że niektóre składniki odżywcze, takie jak nukleotydurydyny, cholina i wielonienasycone kwasy tłuszczowe omega 3, działając synergistycznie, zwiększają stężenie fosfolipidów w błonach komórkowych synaps, prowadzą do tworzenia nowych synaps i poprawy ich funkcji, opracowano i poddano badaniom klinicznym wieloskładnikowy preparat Souvenaid® (Nutricia N.V., Zoetermer, Netherlands). W przeprowadzonych badaniach klinicznych, którym poddano 438 chorych z wczesną postacią AD, dowiedziono, że Souvenaid® jest bezpieczny, dobrze tolerowany przez pacjentów i powoduje statystycznie znamienną poprawę pamięci odroczonej i natychmiastowej. Konieczne są jednak dalsze badania kliniczne w celu potwierdzenia skuteczności tej koncepcji terapeutycznej

Metastasis inhibition after proton beam, β- and γ-irradiation of melanoma growing in the hamster eye

Standard ocular tumor treatment includes brachytherapy, as well as proton therapy, particularly for large melanoma tumors. However, the effects of different radiation types on the metastatic spread is not clear. We aimed at comparing ruthenium (106 Ru, emitting β electrons) and iodine (125I, γ-radiation) brachytherapy and proton beam therapy of melanoma implanted into the hamster eye on development of spontaneous lung metastases. Tumors of Bomirski Hamster Melanoma (BHM) implanted into the anterior chamber of the hamster eye grew aggressively and completely filled the anterior chamber within 8–10 days. Metastases, mainly in the lung, were found in 100% of untreated animals 30 days after enucleation. Tumors were irradiated at a dose of 3–10 Gy with a 106Ru plaque and at a dose of 6–14 Gy using a 125I plaque. The protons were accelerated using the AIC-144 isochronous cyclotron operating at 60 MeV. BHM tumors located in the anterior chamber of the eye were irradiated with 10 Gy, for the depth of 3.88 mm. All radiation types caused inhibition of tumor growth by about 10 days. An increase in the number of metastases was observed for 3 Gy of β-irradiation, whereas at 10 Gy an inhibition of metastasis was found. γ-radiation reduced the metastatic mass at all applied doses, and proton beam therapy at 10 Gy also inhibited the metastastic spread. These results are discussed in the context of recent clinical and molecular data on radiation effects on metastasis

Silver nanoparticles induced changes in DNA methylation and histone H3 methylation in a mouse model of breast cancer

The importance of epigenetic changes as a measurable endpoint in nanotoxicological studies is getting more and more appreciated. In the present work, we analyzed the epigenetic effects induced by citrate- and PEG-coated 20 nm silver nanoparticles (AgNPs) in a model consisting of 4T1 breast cancer tumors in mice. Animals were administered with AgNPs intragastrically (1 mg/kg b.w. daily—total dose 14 mg/kg b.w.) or intravenously (administration twice with 1 mg/kg b.w.—total dose 2 mg/kg b.w.). We observed a significant decrease in 5-methylcytosine (5-mC) level in tumors from mice treated with citrate-coated AgNPs regardless of the route of administration. For PEG-coated AgNPs, a significant decrease in DNA methylation was observed only after intravenous administration. Moreover, treatment of 4T1 tumor-bearing mice with AgNPs decreased histone H3 methylation in tumor tissue. This effect was the most pronounced for PEG-coated AgNPs administered intravenously. No changes in histone H3 Lys9 acetylation were observed. The decrease in methylation of DNA and histone H3 was accompanied by changes in expression of genes encoding chromatin-modifying enzymes (Setd4, Setdb1, Smyd3, Suv39h1, Suv420h1, Whsc1, Kdm1a, Kdm5b, Esco2, Hat1, Myst3, Hdac5, Dnmt1, Ube2b, and Usp22) and genes related to carcinogenesis (Akt1, Brca1, Brca2, Mlh1, Myb, Ccnd1, and Src). The significance of the observed changes and the mechanisms responsible for their development are unclear, and more research in this area is warranted. Nevertheless, the present work points to the epigenetic effects as an important level of interaction between nanomaterials and biological systems, which should always be taken into consideration during analysis of the biological activity of nanomaterials and development of nanopharmaceuticals

MicroRNAs are intensively regulated during induction of somatic embryogenesis in Arabidopsis

Several genes encoding transcription factors (TFs) were indicated to have a key role in the induction of somatic embryogenesis (SE), which is triggered in the somatic cells of plants. In order to further explore the genetic regulatory network that is involved in the embryogenic transition induced in plant somatic cells, micro-RNA (miRNAs) molecules, the products of MIRNA (MIR) genes and the common regulators of TF transcripts, were analyzed in an embryogenic culture of Arabidopsis thaliana. In total, the expression of 190 genes of the 114 MIRNA families was monitored during SE induction and the levels of the primary (pri-miRNAs) transcripts vs. the mature miRNAs were investigated. The results revealed that the majority (98%) of the MIR genes were active and that most of them (64%) were differentially expressed during SE. A distinct attribute of the MIR expression in SE was the strong repression of MIR transcripts at the early stage of SE followed by their significant up-regulation in the advanced stage of SE. Comparison of the mature miRNAs vs. pri-miRNAs suggested that the extensive post-transcriptional regulation of miRNA is associated with SE induction. Candidate miRNA molecules of the assumed function in the embryogenic response were identified among the mature miRNAs that had a differential expression in SE, including miR156, miR157, miR159, miR160, miR164, miR166, miR169, miR319, miR390, miR393, miR396, and miR398. Consistent with the central role of phytohormones and stress factors in SE induction, the functions of the candidate miRNAs were annotated to phytohormone and stress responses. To confirm the functions of the candidate miRNAs in SE, the expression patterns of the mature miRNAs and their presumed targets were compared and regulatory relation during SE was indicated for most of the analyzed miRNA-target pairs. The results of the study contribute to the refinement of the miRNA-controlled regulatory pathways that operate during embryogenic induction in plants and provide a valuable platform for the identification of the genes that are targeted by the candidate miRNAs in SE induction

Visualization and quantitative 3D analysis of intraocular melanoma and its vascularization in a hamster eye

A tumor vasculature network undergoes intense growth and rebuilding during tumor growth. Traditionally, vascular networks are histologically examined using parameters such as vessel density determined from two-dimensional slices of the tumor. Two-dimensional probing of a complicated three-dimensional (3D) structure only provides partial information. Therefore, we propose the use of microcomputed tomography (micro-CT) imaging to analyze the evolution of a tumor vasculature in an experimental ocular tumor model. A Bomirski Hamster Melanoma was implanted in the anterior chamber of a hamster eye. Ultrasound (US) imaging of the same tumor was performed in vivo, and the vascular results obtained using the two methods were compared. Normal ocular tissues, a tumor, and a tumor vascular structure were revealed with high accuracy using micro-CT. The vessels that grew within the tumor were chaotic, leaky, and contained many convoluted micro-vessels and embolizations. They comprised 20–38% of the tumor mass. The blood flow in the larger functional vessels was in the range from 10 to 25 mm/s, as determined by in vivo Doppler US. The micro-CT imaging of the hamster eyeball enabled both qualitative and quantitative 3D analyses of the globe at a histological level. Although the presented images were obtained ex vivo, micro-CT noninvasive imaging is being developed intensively, and high-resolution in vivo imaging is feasible