An in vitro Study to Assess the Potential of a Unique Micro porous Algal Derived Cap Bone Void Filler in Comparison with Clinically-Used Bone Void Fillers

Macroporosity(>100µm) in bone void fillers is a known prerequisite for tissue regeneration, but recent literature has highlighted the added benefit of microporosity(0.5 - 10µm). The aim of this study was to compare the in vitro performances of a novel interconnective microporous hydroxyapatite (HA) derived from red algae to four clinically available macroporous calcium phosphate (CaP) bone void fillers. The use of algae as a starting material for this novel void filler overcomes the issue of sustainability, which overshadows continued use of scleractinian coral in the production of some commercially available materials, namely Pro-OsteonTM and Bio-Coral®. This study investigated the physicochemical properties of each bone voidfiller material using x-ray diffraction, fourier transform infrared spectroscopy, inductive coupled plasma, and nitrogen gas absorption and mercury porosimetry. Biochemical analysis, XTT, picogreen and alkaline phosphatase assays were used to evaluate the biological performances of the five materials. Results showed that algal HA is non-toxic to human foetal osteoblast (hFOB) cells and supports cell proliferation and differentiation. The preliminary in vitro testing of microporous algal-HA suggests that it is comparable to the four clinically approved macroporous bone void fillers tested. The results demonstrate that microporous algal HA has good potential for use in vivo and in new tissue engineered strategies for hard tissue repair.

Expression of complement components and regulators by different subtypes of bone marrow-derived macrophages

Under inflammatory conditions, macrophages can differentiate into different functional subtypes. We show that bone marrow-derived macrophages constitutively express different levels of various complement-related genes. The relative expression levels are C1qb > Crry > CFH > C3 > C1r > CFB > DAF1 > CD59a > C2 > C1INH > C1s > C4. Upon activation, the expression of C1r, C1s, C3, C2, CFB, and C1INH was up-regulated, and CFH, CD59a, and DAF1, down-regulated in M1 (induced by interferon-? + lipopolysaccharides (LPS)) and M2b (induced by immune complex + LPS) macrophages. The expression of C4 and CFH was slightly up-regulated in interleukin (IL)-10-induced M2c macrophages. Complement gene expression in IL-4-induced M2a macrophages was weakly down-regulated as compared to resting M0 macrophages. Higher levels of C3, C1INH, and CFB but lower levels of CFH expression in M1 and M2b macrophage suggests that they may be involved in the alternative pathway of complement activation during inflammation.

Dietary patterns and bone mineral status in young adults: the Northern Ireland Young Hearts Project

Studies of individual nutrients or foods have revealed much about dietary influences on bone. Multiple food or nutrient approaches, such as dietary pattern analysis, could offer further insight but research is limited and largely confined to older adults. We examined the relationship between dietary patterns, obtained by a posteriori and a priori methods, and bone mineral status (BMS; collective term for bone mineral content (BMC) and bone mineral density (BMD)) in young adults (20-25 years; n 489). Diet was assessed by 7 d diet history and BMD and BMC were determined at the lumbar spine and femoral neck (FN). A posteriori dietary patterns were derived using principal component analysis (PCA) and three a priori dietary quality scores were applied (dietary diversity score (DDS), nutritional risk score and Mediterranean diet score). For the PCA-derived dietary patterns, women in the top compared to the bottom fifth of the 'Nuts and Meat' pattern had greater FN BMD by 0.074 g/cm(2) (P=0.049) and FN BMC by 0.40 g (P=0.034) after adjustment for confounders. Similarly, men in the top compared to the bottom fifth of the 'Refined' pattern had lower FN BMC by 0.41 g (P-0.049). For the a priori DDS, women in the top compared to the bottom third had lower FN BMD by 0.05 g/cm(2) after adjustments (P=0.052), but no other relationships with BMS were identified. In conclusion, adherence to a 'Nuts and Meat' dietary pattern may be associated with greater BMS in young women and a 'Refined' dietary pattern may be detrimental for bone health in young men.

Long-term bone marrow culture profiles in patients with myelodysplastic syndromes are not explicable by defective apoptosis

It has been suggested that increased intramedullary apoptosis may explain the paradox between peripheral blood cytopenias and the hyper- or normo-cellular bone marrow observed in the myelodysplastic syndromes (MDS). We wished to see if culture performance could be related to the presence of apoptotic cells in a group of patients with MDS (12 patients) and other patients with peripheral blood cytopenias (six patients) which caused diagnostic difficulty. There was no correlation between LTBMC or adherent cell growth and the presence of apoptotic cells in the original marrow sample. A variable degree of apoptosis was observed in both groups of patients. LTBMC profiles correlated well with diagnosis but were unrelated to the extent of intramedullary apoptosis. This suggests that apoptosis is a much more ubiquitous process in disease than previously thought. (C) 1998 Elsevier Science Ltd. All rights reserved.

A practical miniature long-term bone marrow culture system for investigating early myelodysplasia

A method was devised to grow haemopoietic cells in long-term bone marrow culture (LTBMC) which requires only 1 x 10(6) cells/culture. Such miniature cultures were used to study growth patterns of marrow from patients with myelodysplastic syndromes (MDS). Consistent differences in LTBMC cellularity and cellular composition were noted between MDS and normal marrow. These differences were accentuated by rGM-CSF. The criteria which distinguished between and MDS marrows were: cell count at weeks 1 and 4, % neutrophils and % blasts. In 10 patients with unexplained macrocytosis or pancytopenia miniature LTBMC results clearly segregated into either 'normal' or 'MDS' growth patterns. Miniature LTBMC with rGM-CSF may therefore be a useful diagnostic test for early MDS.