Influence of surgical technique,implant shape and diameter on the primary stability in cancellous bone

Summary Achievement of primary stability during surgical placement of dental implants is one of the most important factors for successful osseointegration depending on various anatomical, surgical and implant‐related factors. Resonance frequency analysis (RFA) has been shown as a non‐invasive and objective technique for measuring the stability of implants. The aim of this study was to evaluate the effect of some surgical and implant‐related factors in enhancing primary stability and to estimate a correlation between RFA and insertion torque (IT) in proximal regions of cow ribs representing cancellous bone. Fifteen implant beds were prepared in the most proximal region of six fresh cow ribs. Ninety implants with three different shapes and two different diameters were placed with two different surgical techniques, and the primary stability was compared using RFA and IT. Significantly higher RFA and IT values were achieved when under‐dimensioned drilling was used as the surgical method (P < 0·01); significantly higher IT values were obtained with the use of wider implants (P < 0·01) and partially conical Astra Tech implants showed the highest IT values (P < 0·01). When all the implants were considered, significant correlations between the IT and RFA values were noted (%40·6, P < 0·05). Partially conical implants with a wide diameter to be placed with the modified surgical technique proposed appear to be useful in enhancing the primary stability in cancellous bone.     

Prophylactic vaccine approach for colon and pancreatic cancers: present and future

Vaccines against cancers have not been as effective as vaccines against infectious diseases. However, recent studies have advanced our understanding of the stages of tumor cell development and of mechanisms of immune surveillance, immune suppression, and of tumor escape from the immune system. The development of animal models that mimic development of human cancers has helped advance the understanding of these processes and is aiding the development of greatly improved vaccines. Here we review the recent progress in developing vaccines and prophylactic approaches for pancreatic and colon cancers. Improved understanding of the expression of various oncogenes and tumor-associated antigens helps in selecting antigenic targets for stage-specific immune prevention. Identification of the earliest alterations in precancerous lesions and selection of epitopes unique to the aberrant cells and capable of triggering strong cytotoxic and helper T cell responses may aid the development of safe and effective vaccines for use in those at high risk of progressing to invasive cancers. The responses can be enhanced with carefully selected adjuvants to boost immunity and by selecting epitopes that are expressed on dendritic cells, thereby promoting T cell responses. Tumor resistance via loss of the targeted antigen can be mitigated by inclusion of multiple tumor epitopes in vaccine constructs. Tumor immune escape can be diminished by targeting various immunosuppressive mechanisms used by different tumors, such as tumor production of immunosuppressive cytokines (e.g., interleukin 10, and Transforming Growth Factor-beta, which can promote activity of immunosuppressive regulatory T cells), or by inhibiting production of inflammatory prostanoids with combined cyclooxygenase/lipoxygenase inhibitors. Finally, prevention of many cancers may be enhanced by carefully selecting and scheduling of vaccine administration in combination with other chemotherapeutic or chemopreventive agents. Preclinical and early clinical trials incorporating these principles are discussed.     

Role of lipoxins, resolvins, and other bioactive lipids in colon and pancreatic cancer

Unresolved inflammation, due to insufficient production of proresolving anti-inflammatory lipid mediators, can lead to an increased risk of tumorigenesis and tumor cell invasiveness. Various bioactive lipids, particularly those formed by cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, have been well established as therapeutic targets for many epithelial cancers. Emerging studies suggest that there is a role for anti-inflammatory bioactive lipids and their mediators during the resolution phase of inflammation. These proresolving bioactive lipids, including lipoxins (LXs) and resolvins (RVs), have potent anti-inflammatory and anti-carcinogenic properties. The molecular signaling pathways controlling generation and degradation of the proresolving mediators LXs and RVs are now being elucidated, and the component molecules may serve as new targets for regulation of inflammation and inflammation-associated cancers like colon and pancreatic cancers. This review will highlight the recent advances in our understanding of how these bioactive lipids and proresolving mediators may function with various immune cells and cytokines in inhibiting tumor cell proliferation and progression and invasiveness of colon and pancreatic cancers.     

Emerging Therapeutic Targets in Diffuse Large B-Cell Lymphoma

The standard front-line treatment of Diffuse Large B-Cell Lymphoma (DLBCL) remains Rituximab combined with multi-agent cytotoxic chemotherapy. In spite of high response rates to this therapy, relapsed/refractory disease is observed in up to 40% of patients. It is our opinion that additional chemoimmunotherapy, followed by high-dose therapy with autologous stem cell transplant (HDT-ASCT) for responsive disease, is the optimal therapy for these patients. However, many patients cannot tolerate HDT-ASCT, or have relapsed/refractory disease in spite of it. These patients have a poor overall prognosis, and there is no clear consensus as to how these patients should be treated. Over the past decade, significant advances have been made in the understanding of the molecular genesis and subtyping of DLBCL, leading to the identification of multiple pathways and molecules that can be targeted for clinical benefit. Examples include Bcl-2, Bcl-6, cell surface markers, and myriad molecules in both the B-Cell receptor and PI3K/Akt/mTOR pathways. As agents targeting these molecules and pathways progress from preclinical models to early clinical trials, more is learned about what might predict for response to these agents, such as cell of origin classification, and/or expression of relevant molecular markers, as measured by immunohistochemistry or gene expression profiling. Both the successes and failures of these novel targeted agents promise to dramatically refine, improve, and individualize the classification and treatment of DLBCL. Therefore, it is our opinion that patients with relapsed/refractory DLBCL are an ideal population for clinical trials due to both the lack of standardized treatment, and the recent advancements in pathobiology and early-phase treatment options.     

Cyberknife Radiosurgery for Basal Skull Plasmacytoma

The Cyberknife delivers frameless image-guided stereotactic radiosurgery to intracranial and extracranial tumors. We report our use of Cyberknife radiosurgery on a medullary plasmacytoma in the clivus extending into the foramen magnum. No acute toxicity was seen during or within 24 hours of treatment, and the subject had a complete and durable radiographic response on MRI 12+ months after treatment. To our knowledge, this is a first case of successful Cyberknife radiosurgery of a medullary plasmacytoma.