Chemical Properties of Human Dentin Blocks and Vertical Augmentation by Ultrasonically Demineralized Dentin Matrix Blocks on Scratched Skull without Periosteum of Adult-Aged Rats

Vertical augmentation is one of the most challenging techniques in bone engineering. Several parameters, such mechano-chemical characteristics, are important to optimize vertical bone regeneration using biomaterials. The aims of this study were to chemically characterize human dentin blocks (calcified demineralized dentin matrix: CDM, partially demineralized dentin matrix: PDDM and completely demineralized dentin matrix: CDDM) (2 × 2 × 1 mm3) chemically and evaluate the behavior of PDDM blocks on non-scratched or scratched skulls without periosteum of adult rats (10–12 months old, female) as a vertical augmentation model. The dissolved efficiency of CDM showed 32.3% after ultrasonic demineralization in 1.0 L of 2% HNO3 for 30 min. The 30 min-demineralized dentin was named PDDM. The SEM images of PDDM showed the opening of dentinal tubes, nano-microcracks and the smooth surface. In the collagenase digestion test, the weight-decreasing rates of CDM, PDDM and CDDM were 9.2%, 25.5% and 78.3% at 12 weeks, respectively. CDM inhibited the collagenase digestion, compared with PDDM and CDDM. In the PDDM onlay graft on an ultrasonically scratched skull, the bone marrow-space opening from original bone was found in the bony bridge formation between the human PDDM block and dense skull of adult senior rats at 4 and 8 weeks. On the other hand, in the cases of the marrow-space closing in both non-scratched skulls and scratched skulls, the bony bridge was not formed. The results indicated that the ultrasonic scratching into the compact parietal bone might contribute greatly to the marrow-space opening from skull and the supply of marrow cells, and then bony bridge formation could occur in the vertical augmentation model without a periosteum.

Myeloproliferative neoplasm related nephropathy

Primary Myelofibrosis associated Nephropathy is a recently described entity. Primary Myelofibrosis (PMF) is a Myeloproliferative Neoplasm (MPN) where the marrow space shows fibrosis with megakaryocyte dysplasia. We present a case of a 32 year old patient who was detected to have proteinuria, renal dysfunction and anemia ,on a routine health check up. Primary Myelofibrosis was confirmed by positive Jak 2 expression. Kidney biopsy showed focal segmental glomerulosclerosis along with thickened glomerular basement membrane. The histomorphological features of renal and bonemarrow biopsies are analysed and a detailed review of the literature is done.

Direct Intravital Imaging of the Bone Marrow and Splenic Hematopoietic Niches in Individual Mice to Define the Early Engraftment Kinetics Following HSC-Transplant

Hematopoietic stem cells (HSCs) give rise to and maintain the entire hematopoietic system for the life of an organism. This remarkable feat has established HSC transplant as an indispensable tool for treating a variety of hematological disorders. Yet the initial steps of homing, engraftment, and clonal expansion, which lead to eventual long-term hematopoietic recovery after HSC transplant, remain incompletely characterized. Given the determinative effect that early HSC activity has on transplant outcomes, a more complete understanding of initial engraftment dynamics is imperative for bettering HSC therapies. Preliminary studies aimed at functional characterization of classic HSC and hematopoietic stem and progenitor cell (HSPC) populations-namely the CD150 +CD48 -Sca-1 +c-Kit +Lin - (SLAM SKL) and Sca-1 +c-Kit +Lin - (SKL) populations, respectively-revealed that these populations exhibit disparate early engraftment dynamics. Using previously developed intravital imaging techniques, we were able to partially characterize early HSC and HSPC engraftment dynamics in mice competitively transplanted with GFP + SLAM SKL and DsRed + SKL cells. The SKL population was found to primarily engraft in the bone marrow, completely recapitulating engraftment behavior of transplanted whole bone marrow. In contrast, the more purified SLAM SKL population engrafted poorly in the marrow space and instead preferentially engrafted in the spleen, where it produced the majority of donor-derived blood at early stages (7 days) after competitive transplant into lethally irradiated mice. However, by 14 days post-transplant, SLAM SKL-derived cells migrated from the spleen to repopulate the majority of bone marrow space. These results reflect the dynamic nature of hematopoietic recovery in a myeloablative model and highlight the need for in vivo imaging techniques to fully understand hematopoietic reconstitution by the SLAM SKL population. In order to further dissect the interactive processes of bone marrow hematopoiesis and splenic extramedullary hematopoiesis, we have developed a novel, multi-organ intravital imaging technique that allows for simultaneous analysis of defined hematopoietic compartments in a single animal. Our multimodal imaging approach combines direct visualization of fluorescently labeled hematopoietic cells in the spleen via our recently developed spleen window, with concomitant observation of hematopoietic cells in tibia marrow environment. Our spleen window is a specially engineered biocompatible ring with an affixed coverslip to allow for direct, non-invasive microscopic visualization of labeled hematopoietic cells in the spleen. The spleen window can be installed with the tibia window in an individual mouse. Multimodal mice can be visualized repeatedly over a minimum of 7 days post-HSC transplant to follow individual cell behaviors within the living recipient. Preliminary results from competitive repopulation assays utilizing our multimodal imaging approach suggest that the SLAM SKL population is an active one that confers rapid hematopoietic recovery in lethally irradiated recipients primarily from extramedullary hematopoiesis in the spleen (CFU-S). The results of ongoing work characterizing the active use of the splenic and marrow niches will be presented. Disclosures Cogle: Celgene: Membership on an entity's Board of Directors or advisory committees; Aptevo therapeutics: Research Funding.

The Bone Cartilage Interface and Osteoarthritis

This review describes results obtained with tissue from prior studies of equine and human osteoarthritis (OA). The main methods considered are scanning electron microscopy, novel methods in light microscopy and X-ray Micro-tomography. The same samples have been re-utilised in several ways. The tissues described are hyaline articular cartilage (HAC; or substitutes), with its deep layer, articular calcified cartilage (ACC), whose deep surface is resorbed in cutting cone events to allow the deposition of subchondral bone (SCB). Multiple tidemarks are normal. Turnover at the osteochondral (ACC-HAC-SCB) junction is downregulated by overload exercise, conversely, during rest periods. Consequent lack of support predisposes to microfracture of the ACC-SCB plate, in the resorption-related repair phase of which the plate is further undermined to form sink holes. The following characteristics contribute to the OA scenario: penetrating resorption canals and local loss of ACC; cracking of ACC and SCB; sealing of cracks with High-Density Mineral Infill (HDMI); extrusion of HDMI into HAC to form High-Density Mineral Protrusions (HDMP) in HAC which may fragment and contribute to its destruction; SCB marrow space infilling and densification with (at first) woven bone; disruption, fibrillation and loss of HAC; eburnation; repair with abnormal tissues including fibrocartilage and woven bone; attachment of Sharpey fibres to SCB trabeculae and adipocyte-moulded extensions to trabeculae (excrescences).

Evaluation of quasi-static and dynamic nanomechanical properties of bone-metastatic breast cancer cells using a nanoclay cancer testbed

In recent years, there has been increasing interest in investigating the mechanical properties of individual cells to delineate disease mechanisms. Reorganization of cytoskeleton facilitates the colonization of metastatic breast cancer at bone marrow space, leading to bone metastasis. Here, we report evaluation of mechanical properties of two breast cancer cells with different metastatic ability at the site of bone metastases, using quasi-static and dynamic nanoindentation methods. Our results showed that the significant reduction in elastic modulus along with increased liquid-like behavior of bone metastasized MCF-7 cells was induced by depolymerization and reorganization of F-actin to the adherens junctions, whereas bone metastasized MDA-MB-231 cells showed insignificant changes in elastic modulus and F-actin reorganization over time, compared to their respective as-received counterparts. Taken together, our data demonstrate evolution of breast cancer cell mechanics at bone metastases.

Histomorphometric evaluation of the effects of local application of red cloveroil (trifolium pratense) on bone healing in rats

Background: Red clover oil (Trifolium pratense) has isoflavones bunches which have estrogen-like exercises and may establish an option in contrast to hormone substitution treatment. The present study investigated the impact of Red clover oil on bone healing in rats by histomorphometric study. Materials and Methods: Intra bony defect was performed in right femur of thirty six healthy male albino rats. Then these rats were randomly divided into three groups (12 rats each): one control and 2 experimental groups. For control, the bony defect was left for normal healing; for the experimental (S) group, the defect was treated with hemostatic absorbable gelatin sponge; and for experimental (RS) group, the bony defect was treated with 0.2 ml red clover oil and covered by haemostatic absorbable gelatin sponge. Six rats from each group were sacrificed at 2 and 4 weeks intervals. Histomorphometric analysis was performed on H&E bone section of all the studied groups which includes counting of bone cells (osteoblasts, osteocytes and osteoclasts), trabecular number, trabecular area and bone marrow space area. Results: Histomorphometric results of bone cells revealed that the combination group stimulated larger numbers of osteoblasts and osteocytes than in sponge and control group. Number of new bone trabeculae, trabecular area and bone marrow space area showed higher mean values in combination groups than others. Highly significant differences between groups were observed in all histomorphometric parameters throughout all durations. Conclusion: Red clover oil stimulated larger numbers of osteoblasts and osteoclasts, indicating increased bone remodeling especially at 2 weeks interval as compared with sponge and control groups. Key words: Bone defect, Red clover, Rats.