Culture expansion in low-glucose conditions preserves chondrocyte differentiation and enhances their subsequent capacity to form cartilage tissue in three-dimensional culture.

Culture conditions that preserve a stable chondrocyte phenotype are desirable in cell-based cartilage repair to maximize efficacy and clinical outcome. This study investigates whether low-glucose conditions will preserve the chondrocyte phenotype during culture expansion. Articular chondrocytes were culture-expanded in media supplemented with either low (1 mM) or high (10 mM) glucose. The metabolic phenotype, reactive oxygen species generation, and mRNA expression of markers of differentiation or catabolism were assessed by reverse-transcription quantitative polymerase chain reaction after four population doublings (PDs) and subsequent tissue formation capacity determined using pellet cultures. Continuous monolayer culture was used to determine the population doubling limit. After expansion in monolayer for four PDs, chondrocytes expanded in low-glucose conditions exhibited higher expression of the differentiation markers SOX9 and COL2A1 and reduced expression of the catabolic metalloproteinase matrix metallopeptidase 13. When chondrocytes expanded in low glucose were cultured in micropellets, they consistently generated more cartilaginous extracellular matrix than those expanded in high glucose, as evaluated by wet weight, sulfated glycosaminoglycan content, and hydroxyproline assay for collagen content. The same pattern was observed whether high or low glucose was used during the pellet culture. During expansion, chondrocytes in high-glucose generated 50% more reactive oxygen species than low-glucose conditions, despite a lower dependence on oxidative phosphorylation for energy. Furthermore low-glucose cells exhibited >30% increased population doubling limit. These data suggests that low-glucose expansion conditions better preserve the expression of differentiation markers by chondrocytes and enhance their subsequent capacity to form cartilage in vitro. Therefore, low glucose levels should be considered for the expansion of chondrocytes intended for tissue engineering applications.This study was funded by the Medical Research Council/Engineering and Physical Sciences Research Council (EPSRC) discipline bridging initiative grant PPA026, EPSRC Platform Grant EP/E046975/1; Human Frontier Science Program Grant RGP0025/2009-C and Arthritis Research U.K. grants 19654 and 19344

Guiding properties of a non-isothermal atmosphere for acoustic-gravity waves

The propagation of pressure waves in a stratified, non-isothermal atmosphere is studied in the linear approximation. It is found that acoustic and acoustic-gravity waves can be horizontally guided by the effect of the Earth’s thermocline alone, under very mild conditions on the temperature gradient steepness. The effect of the Earth’s surface is also studied. Lamb’s modes associated with the rigid surface are, then, identified and their behaviour, as a function of the Earth’s position, is discussed. Finally, dissipation is included, and its effect is derived using a perturbation technique

Oyster spat recruitment in Espírito Santo State, Brazil, using recycled materials

Este trabalho avaliou a eficiência de quatro tipos de coletores de sementes no recrutamento de ostras Crassostrea sp., em cinco pontos do estuário do Rio Benevente, município de Anchieta, e em duas ilhas no município de Piúma, estado do Espírito Santo. Foram utilizados quatro tipos de coletores: 1-conchas de ostras, 2- garrafas PET, 3-tiras de pneu e 4- telhas, todos suspensos por cordas e amarrados em rizóforos de Rhizophora mangle ou em "long-lines" de mexilhões. Bimensalmente, as sementes recrutadas foram contadas e medidas quanto à altura, determinando-se os parâmetros físico-químicos-tróficos da água: salinidade, temperatura, oxigênio dissolvido, matéria orgânica particulada e clorofila-a, que foram correlacionados com o número de sementes nos coletores (através de correlações de Spearman). O recrutamento de sementes foi significativamente maior nos coletores de conchas de ostras, telhas e pneus, principalmente nos pontos de salinidade mais alta (Praia do Coqueiro em Anchieta e Ilhas do Meio e do Cabrito em Piúma) (Kruskal-Wallis: H= 10,01; 3 g.l.; P ;0,05). O número de sementes de ostras foi positivamente correlacionado com a salinidade (&#961;s= 0,331; P ; 0.05). The number of oyster spat was positively correlated with the salinity (&#961;s= 0.331; p < 0.05) and water temperature (&#961;s= 0.48; p < 0.05), revealing that areas with higher salinities and summer months were better for spat collection

A homeostatic function of CXCR2 signalling in articular cartilage

Funding This work was funded by Arthritis Research UK (grants 17859, 17971, 19654), INNOCHEM EU FP6 (grant LSHB-CT-2005-51867), MRC (MR/K013076/1) and the William Harvey Research FoundationPeer reviewedPublisher PD

Sonocrystallisation of ZIF-8 in water with high excess of ligand: Effects of frequency, power and sonication time

A systematic study on the sonocrystallisation of ZIF-8 (zeolitic imidazolate framework-8) in a water-based system was investigated under different mixing speeds, ultrasound frequencies, calorimetric powers and sonication time. Regardless of the synthesis technique, pure crystals of ZIF-8 with high BET (Brunauer, Emmett and Teller) specific surface area (SSA) can be obtained in water after only 5 s. Furthermore, 5 s sonication produced even smaller crystals (~0.08 µm). The type of technique applied for producing the ZIF-8 crystals did not have any significant impact on crystallinity, purity and yield. Crystal morphology and size were affected by the use of ultrasound and mixing, obtaining nanoparticles with a more spherical shape than in silent condition (no ultrasound and mixing). However, no specific trends were observed with varying frequency, calorimetric power and mixing speed. Ultrasound and mixing may have an effect on the nucleation step, causing the fast production of nucleation centres. Furthermore, the BET SSA increased with increasing mixing speed. With ultrasound, the BET SSA is between the values obtained under silent condition and with mixing. A competition between micromixing and shockwaves has been proposed when sonication is used for ZIF-8 production. The former increases the BET SSA, while the latter could be responsible for porosity damage, causing a decrease of the surface area. © 2021 The Author(s

Determinazione di residui di sparo in ferite d\u2019arma da fuoco putrefatte mediante Micro-TC

Introduzione: La Micro-TC \ue8 un mezzo rapido e preciso per la determinazione del gunshot-residue (GSR) su ferite d\u2019arma da fuoco ai fini della determinazione della distanza di sparo. \uc8 noto come la disepitelizzazione e la colliquazione della cute e del sottocute indotte dai fenomeni autolitici-putrefattivi rendano difficoltosa l\u2019analisi ispettiva delle ferite cutanee. Il presente studio si propone di testare l\u2019efficienza diagnostica della Micro-TC nell\u2019identificazione e quantificazione del GSR su ferite d\u2019arma da fuoco sottoposte a putrefazione standardizzata. Materiali e metodi: Previa autorizzazione del Comitato Etico, 10 gambe umane amputate chirurgicamente sono state sezionate in 3 segmenti di circa 6 cm (totale 30 segmenti) e sottoposte a prove di sparo da tre differenti distanze (5, 15 e 30 cm) mediante l\u2019utilizzo di una pistola semi-automatica calibro 7.65 mm fissata su un supporto rigido. I pezzi anatomici sono stati posti in cassette di legno, conservati all\u2019aria aperta per 10 giorni e successivamente fissati in formalina al 4%. Sono stati quindi ottenuti campioni cutanei di forma cubica (lato di cm 1) comprendenti il foro di ingresso o di uscita, il tramite e i tessuti molli circostanti. Ogni campione \ue8 stato sottoposto a esame con Micro-TC e ricostruito in 3D. La percentuale di GSR nella regione di interesse \ue8 stata calcolata mediante un software densitometrico analizzando solo particelle con densit\ue0 superiore a 1000 HU. La stima statistica del modello sulla base del campione rilevato \ue8 stata effettuata mediante la procedura PROC NLIN di SAS\uae. Risultati: L\u2019analisi ispettiva delle ferite immediatamente dopo le prove balistiche ha evidenziato una progressiva riduzione dell\u2019alone di affumicatura e del tatuaggio all\u2019aumentare della distanza di sparo. A distanza di 10 giorni le caratteristiche accessorie apparivano pi\uf9 sfumate a causa delle modificazioni post-mortali della cute associate alla presenza di larve e muffe. L\u2019analisi con micro-CT ha consentito di individuare residui di sparo sulla superficie cutanea, nel sottocute e lungo il tramite di tutte le ferite di ingresso. Tali residui erano invece sempre assenti a livello dei fori d\u2019uscita. La percentuale di GSR ha mostrato un decremento non lineare al crescere della distanza di sparo; nonostante ci\uf2, la variabilit\ue0 del fenomeno non ha permesso di evidenziare differenze statisticamente significative nella media e deviazione standard dei valori relativi alle diverse distanze testate. Conclusioni: L\u2019analisi con micro-TC di ferite d\u2019arma da fuoco prodotte da colpi esplosi a distanza medio-bassa (fino a 30 cm) consente di porre diagnosi differenziale tra foro di ingresso e di uscita. Le modificazioni cutanee indotte dai fenomeni autolitici e putrefattivi post-mortali inducono una tale variabilit\ue0 nei risultati tale da non permettere l\u2019utilizzo di tale tecnica nella determinazione della distanza di sparo

In vitro concurrent endothelial and osteogenic commitment of adipose-derived stem cells and their genomical analyses through CGH array: novel strategies to increase the succesfull engraftement of a tissue engineered bone grafts

In the field of tissue engineering, adult stem cells are increasingly recognized as an important tool for in vitro reconstructed tissue-engineered grafts. In the world of cell therapies, mesenchymal stem cells from bone marrow or adipose tissue are undoubtedly the most promising progenitors for tissue engineering applications. In this setting, adipose-derived stem cells (ASC) are generally similar to those derived from bone marrow and are most conveniently extracted from tissue removed in elective cosmetic liposuction procedures; they also show a great potential for endothelization. The aim of the present work was to investigate how the co-commitment into a vascular and bone phenotype of ASC could be a usefull tools for improving the in vitro and in vivo reconstruction of a vascularized bone graft. Human ASC obtained from abdominoplasty procedures were loaded in a hydroxyapatite clinical-grade scaffold, co-differentiated and tested for proliferation, cell distribution, and osteogenic and vasculogenic gene expression. The chromosomal stability of the cultures was investigated using the CGH array for 3D cultures. ASC adhesion, distribution, proliferation and gene expression not only demonstrated a full osteogenic and vasculogenic commitment in vitro and in vivo, but also showed that endothelization strongly improves their osteogenic commitment. In the end, genetic analyses confirmed that no genomical alteration in long-term in vitro culture of ASC in 3D scaffolds occurs