The Effect of Surface Pretreatment and Water Storage on the Bonding Strength of a Resin Composite Cement to Modified PEEK

The bonding quality of bonding to polyether ether ketone (PEEK) after different surface treatments and adhesive regimens was assessed through shear bond strength.

MATERIALS AND METHODS

Sixty modified PEEK disks were cut out of BioHPP round blanks using CAD-CAM procedures. Disks were subjected to the following surface pretreatments: (A) Sandblasting with alumina (Rocatec) and application of adhesive bonding agent visiolink (control group) (B) Sandblasting with silica-modified alumina (Cojet), application of silane agent Espe Sil, followed by application of adhesive bonding agent Visio-Bond (C) Sandblasting with silica-modified alumina (Cojet), application of silane containing primer-adhesive Clearfil Ceramic Primer, followed by application of adhesive bonding agent visiolink. A dual-curing resin composite cement (combolign) was luted to all treated surfaces. Each group was further divided to subgroups of 10 specimens which were stored in distilled water at 37°C for 150 days without further thermocycling. Specimens were then submitted to shear bond strength testing.

RESULTS

Group (B) was statistically significant different from group (A) (control group). Water storage condition had no significant influence on final bond strength.

CONCLUSIONS

Use of different conditioning protocols had a significant effect on the final bond strength of composite resin cement to PEEK surface. Water storage did not significantly influence bonding.

Assays for Qualification and Quality Stratification of Clinical Biospecimens Used in Research: A Technical Report from the ISBER Biospecimen Science Working Group

This technical report presents quality control (QC) assays that can be performed in order to qualify clinical biospecimens that have been biobanked for use in research. Some QC assays are specific to a disease area. Some QC assays are specific to a particular downstream analytical platform. When such a qualification is not possible, QC assays are presented that can be performed to stratify clinical biospecimens according to their biomolecular quality.

Reconstruction of 3-dimensional histology volume and its application to study mouse mammary glands

Histology volume reconstruction facilitates the study of 3D shape and volume change of an organ at the level of macrostructures made up of cells. It can also be used to investigate and validate novel techniques and algorithms in volumetric medical imaging and therapies. Creating 3D high-resolution atlases of different organs(1,2,3) is another application of histology volume reconstruction. This provides a resource for investigating tissue structures and the spatial relationship between various cellular features. We present an image registration approach for histology volume reconstruction, which uses a set of optical blockface images. The reconstructed histology volume represents a reliable shape of the processed specimen with no propagated post-processing registration error. The Hematoxylin and Eosin (H&E) stained sections of two mouse mammary glands were registered to their corresponding blockface images using boundary points extracted from the edges of the specimen in histology and blockface images. The accuracy of the registration was visually evaluated. The alignment of the macrostructures of the mammary glands was also visually assessed at high resolution. This study delineates the different steps of this image registration pipeline, ranging from excision of the mammary gland through to 3D histology volume reconstruction. While 2D histology images reveal the structural differences between pairs of sections, 3D histology volume provides the ability to visualize the differences in shape and volume of the mammary glands.

Abstract 5013: Loss of Igfbp7 leads to the expansion of luminal progenitors by altering the stromal fibroblasts’ ability to support luminal cell differentiation

Insulin-like growth factor binding protein 7, IGFBP7, is a secreted glycoprotein that unlike other IGFBPs, binds insulin with higher affinity than IGFs. Interestingly, high-grade invasive breast cancers lack IGFBP7 expression, and its low expression levels is associated with reduced patient survival. Interestingly, in some cancers expression of IGFBP7 is lost due to promoter methylation or loss of hetrozygosity. Also, in vivo xenograft assays have shown that IGFBP7 can suppress breast cancer cell proliferation. These data together imply that IGFBP7 may act as a potential tumor suppressor. Recent evidence suggests that tumor suppressors and oncogenes play essential roles in regulating the normal development of mammary gland and that alterations to their expression or functions may transform the undifferentiated breast stem cells and progenitors into cancer initiating cells. To examine if IGFBP7 plays essential roles in regulating the normal development of the mammary gland, we developed Igfbp7-null mice and examine the development of the mammary glands. Notably, the pre- and post-pubertal Igfbp7-null glands featured decreased overall size and diminished terminal end bud and alveolar densities. However, the Igfbp7-null glands showed the most startling defects during pregnancy and lactation where lobular sacs were severely deformed and decreased in numbers. To ascertain the molecular mechanism underlying this defective lobular development, we compared the transcriptome profiles of the Igfbp7-null glands and the Wild-Type (WT) glands using RNA-Seq technology. Our transcriptome analysis revealed the decreased expression of a number of key signaling molecules involved in the Notch and IGF/Insulin and other signaling pathways. Interestingly our analysis also revealed the decreased expression of luminal cell differentiation-associated genes such as Gata3 and Pml. Through quantifying, for the first time, the number of luminal progenitors during the different phases of pregnancy and lactation, we determined that loss of Igfbp7 lead to the increased frequency (up to 5±0.3 folds) and thusly, yield (up to 3±0.25 folds) of the luminal progenitors and yet these Igfbp7-null progenitors are unable to differentiate in vivo. We further show that the Igfbp7-null stromal fibroblasts are unable to support the differentiation of the luminal progenitors. For the first time we demonstrate that loss of a tumor suppressor gene, Igfbp7, can suppress the ability of luminal progenitors to differentiate by altering the properties of stromal fibroblasts. It is interesting that the loss of a tumor suppressor gene would result in the expansion of the luminal progenitors since these progenitors and other undifferentiated cells have been envisaged to be prime cellular targets to accumulate transforming mutations that can cause them to act as cancer initiating cells.

Citation Format: Sumanta Chatterjee, Stephanie Bacopulos, WenYi Yang, Yutaka Amemiya, Demetri Spyropoulos, Arun Seth, Afshin Raouf. Loss of Igfbp7 leads to the expansion of luminal progenitors by altering the stromal fibroblasts’ ability to support luminal cell differentiation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5013. doi:10.1158/1538-7445.AM2013-5013