SSAO was expressed as an active form in rat and human cartilage. The results suggest the involvement of SSAO in rat chondrocyte terminal differentiation via a modulation of the glucose transport. In man, the increased SSAO activity detected in osteoarthritic patients may trigger hypertrophy and cartilage degeneration.

OBJECTIVES: Chondrocytes hypertrophy is a physiological process observed in endochondral ossification during development until adolescence in human. It can also be observed during pathophysiological conditions such as osteoarthritis. Hypertrophic chondrocytes synthesise collagen X and express matrix metalloproteinase 13 and alkaline phosphatase. The cellular models available to study this process are either not convenient, they might lead to a rapid dedifferentiation of chondrocytes, or they are far from the physiological conditions. The objective of this study was to design an user-friendly 2D-primary cell culture of young articular chondrocytes of rat able to follow the terminal differentiation process. EXPERIMENTAL DESIGN: After confluence, chondrocytes were cultured according to 4 differentiation protocols. Protocol 1 contained DMEM/F12 supplemented with 10% foetal bovine serum (FBS) and 2 µg/ml insulin. Protocol 2 contained alpha-MEM supplemented with 5% FBS and 2 µg/ml insulin. Protocol 3 contained 2% FBS and 2 µg/ml insulin. Protocol 4 contained DMEM/F12 supplemented with 2% FBS in absence or in presence of 2 µg/ml insulin and 37.5 µg/ml ascorbate. The cell morphology was observed by phase-contrast microscopy and the expression of markers specific of mature and hypertrophic chondrocytes were assessed by RT-qPCR. RESULTS: The effect of a decrease in nutrient quality of the culture medium after confluence was tested using protocols 1, 2 and 3. Protocol 1 did not allow the maintenance of chondrocyte phenotype more than one week, because cells became fibroblastic. A decrease in Sox9 mRNA expression, in collagen II/collagen I and in aggrecan/versican mRNA ratios was also found with protocol 1. Protocol 3 was the best when compared with protocols 1 and 2. It allowed chondrocytes to adopt a hypertrophic morphology. Cells also expressed the collagen X specific hypertrophic marker, and presented an increase in collagen II/I and aggrecan/versican ratios after 15 days of culture post-confluence. The effect of the insulin/ascorbate supplementation was studied using protocol 4. The insulin/ascorbate supplementation allowed an earlier chondrocytes conversion to terminal differentiation with a prolonged effect till 3 weeks post-confluence, compared to control without insulin/ascorbate. Finally, the profile of chondrocyte differentiation was checked during 5 successive sub-cultures. Only the first passage could be used to study hypertrophy. CONCLUSION: A convenient protocol to study chondrocyte hypertrophy is proposed. Protocol 4 offers the possibility to study this differentiation phenotype which is crucial for the development of articular diseases such as osteoarthritis. Our model could also be used in tissue engineering for cartilage repair strategies in which hypertrophic differentiation of chondrocyte should be avoided.

Purpose: To date, there is no tool for assessing early pragmatic development of Polish-speaking children. This study aimed to adapt to Polish a standardized parent report measure, the Language Use Inventory (LUI; O'Neill, 2009, in order to enable cross-cultural comparisons and to use the LUI-Polish to screen for pragmatic development in children 18-47 months of age. We concentrated on the sociocultural and functional adaptation of LUI and aimed to demonstrate its reliability, developmental sensitivity, and concurrent validity. Method: Parents completed an online version of LUI-Polish, longitudinally at 3 time points (when the child was 20, 32, and 44 months old). In addition, parents completed the Polish adaptations of the Questionnaire for Communication and Early Language at 22 months and the Language Development Survey at 24 months. Children's spontaneous speech was assessed at 24 months, and their expressive and receptive vocabulary was assessed at 36 months. Results: All 3 parts of the LUI-Polish (Gestures, Words, and Sentences) showed very good levels of internal consistency at each time point. Significant correlations were observed between all parts of the LUI-Polish at all 3 measurement time points. The expected developmental trajectory was observed for boys and girls providing evidence of its developmental sensitivity for children between the ages of 2 and 4 years: an increase with age in the total score (due to an increase in Words and Sentences) and a decrease in Gestures. Supporting concurrent validity, significant correlations were found between children's performance on (a) the LUI-Polish at 20 months and the Questionnaire for Communication and Early Language at 22 months as well as the Language Development Survey and spontaneous speech measures at 24 months and (b) the LUI-Polish at 32 months and the 2 measures of vocabulary comprehension and production at 36 months. Conclusion: The Polish adaptation of the LUI demonstrated good psychometric properties that provide a sound basis for cross-cultural comparisons and further research toward norming of the LUI-Polish. Moreover, the expected developmental trajectory in the pragmatic development of Polish children was observed.

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The significance of pointing gestures in the development of linguistic communication is linked to their referential character and formation of common ground in use of gestures and speech. Our longitudinal study aimed to define the nature of this relationship more precisely and to explore whether the relevance vs lack of relevance of a child's pointing gestures is related to development of language abilities. We developed a special protocol to measure relevant and irrelevant pointing gestures in 18-month-olds, sampled production of spontaneous speech and measured their language comprehension at two years of age. A group of 343 children was tested, and using structural equation modelling we showed that relevant gestures predict the level of development of language production and comprehension. As predicted, this association was not applied to irrelevant gestures. It is likely that a child's more frequent use of relevant pointing gestures helps the caregiver to recognize the child's communicative intentions and to comment on his/her behaviour appropriately. The identified developmental/predictive relationship is valid in both mentalistic and teleological interpretation of early communicative development.

The appearance of PTFE-like nanochains in the structure of fluorinated N–graphyne strongly influences both electrochemical and biological properties.

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