Role of Matrix Metalloproteinase 13 in Both Endochondral and Intramembranous Ossification during Skeletal Regeneration

Extracellular matrix (ECM) remodeling is important during bone development and repair. Because matrix metalloproteinase 13 (MMP13, collagenase-3) plays a role in long bone development, we have examined its role during adult skeletal repair. In this study we find that MMP13 is expressed by hypertrophic chondrocytes and osteoblasts in the fracture callus. We demonstrate that MMP13 is required for proper resorption of hypertrophic cartilage and for normal bone remodeling during non-stabilized fracture healing, which occurs via endochondral ossification. However, no difference in callus strength was detected in the absence of MMP13. Transplant of wild-type bone marrow, which reconstitutes cells only of the hematopoietic lineage, did not rescue the endochondral repair defect, indicating that impaired healing in Mmp13−/− mice is intrinsic to cartilage and bone. Mmp13−/− mice also exhibited altered bone remodeling during healing of stabilized fractures and cortical defects via intramembranous ossification. This indicates that the bone phenotype occurs independently from the cartilage phenotype. Taken together, our findings demonstrate that MMP13 is involved in normal remodeling of bone and cartilage during adult skeletal repair, and that MMP13 may act directly in the initial stages of ECM degradation in these tissues prior to invasion of blood vessels and osteoclasts

User Experiences of Development of Dependence on the Synthetic Cannabinoids, 5f-AKB48 and 5F-PB-22, and Subsequent Withdrawal Syndromes

Emergence of synthetic cannabinoids (SCBs) in herbal smoking mixtures is a public health concern. New SCB’s such as 5f-AKB48 and 5F-PB-22 have been detected in French seizures and in sudden death post mortems in the US. The aim was to describe development of dependence on herbal smoking mixtures containing the SCB’s, 5f-AKB48 and 5F-PB-22 and subsequent withdrawal syndromes. Dependent users of herbal smoking mixtures known to contain the SCB’s 5f-AKB48 and 5F-PB-22 with an average Severity of Dependence Score (SDS) of 13 were interviewed using a structured guide (three males/three females). Narratives were analysed using the Empirical Phenomenological Psychological (EPP) five step method. Six themes with 68 categories emerged from the analysis. Themes are illustrated as 1) Networks and Product Availability; 2) Drivers and Motives for Use; 3) Effect and Pathways toward Dependence; 4) Poly Substance Use and Comparisons to Natural Cannabis; 5) Dependence and Withdrawal and 6) Self-detoxification Attempts. Two higher levels of abstraction above these theme-levels emerged from the data, with sole use of herbal smoking mixtures containing 5f-AKB48 and 5F-PB-22 centering on the interplay between intense cravings, compulsive all-consuming seeking, use and re-dose behaviours, and fear of the psychiatric and self-harms caused when in withdrawal. This is the first study describing dependence and withdrawal experiences in users dependent on 5f-AKB48 and 5F-PB-22. Given the potential for adverse psychiatric and physical consequences of dependent use, further development of specific clinical responses and clinical research around toxicity and withdrawal severity are warranted

Principles of cartilage tissue engineering in TMJ reconstruction

Diseases and defects of the temporomandibular joint (TMJ), compromising the cartilaginous layer of the condyle, impose a significant treatment challenge. Different regeneration approaches, especially surgical interventions at the TMJ's cartilage surface, are established treatment methods in maxillofacial surgery but fail to induce a regeneration ad integrum. Cartilage tissue engineering, in contrast, is a newly introduced treatment option in cartilage reconstruction strategies aimed to heal cartilaginous defects. Because cartilage has a limited capacity for intrinsic repair, and even minor lesions or injuries may lead to progressive damage, biological oriented approaches have gained special interest in cartilage therapy. Cell based cartilage regeneration is suggested to improve cartilage repair or reconstruction therapies. Autologous cell implantation, for example, is the first step as a clinically used cell based regeneration option. More advanced or complex therapeutical options (extracorporeal cartilage engineering, genetic engineering, both under evaluation in pre-clinical investigations) have not reached the level of clinical trials but may be approached in the near future. In order to understand cartilage tissue engineering as a new treatment option, an overview of the biological, engineering, and clinical challenges as well as the inherent constraints of the different treatment modalities are given in this paper

Four postmortem case reports with quantitative detection of the synthetic cannabinoid, 5F-PB-22.

In January 2014, the US government temporarily designated 5F-PB-22, along with three other synthetic cannabinoids (AB-FUBINACA, ADB-PINACA and PB-22), into Schedule I. Over the course of a 4-month time period (July-October 2013), our laboratory quantitatively identified 5F-PB-22 in specimens obtained from four postmortem cases. We describe the four cases, to include pertinent autopsy findings and decedent histories, together with quantitative results for 5F-PB-22 determined in postmortem blood and antemortem serum. Samples were prepared via a liquid-liquid extraction at pH 10.2 into hexane : ethyl acetate. Instrumental analysis was achieved with liquid chromatography coupled with electrospray ionization tandem mass spectrometry operating in multiple reaction monitoring mode. Two ion transitions were monitored for the analyte of interest, and one ion transition was monitored for the internal standard. The observed concentration range of 5F-PB-22 is 1.1-1.5 ng/mL for three postmortem blood specimens and one antemortem serum specimen. Three of the decedents experienced abrupt, sudden death; however, one decedent expired after a rapidly deteriorating hospital course

Four Postmortem Case Reports with Quantitative Detection of the Synthetic Cannabinoid, 5F-PB-22

In January 2014, the US government temporarily designated 5F-PB-22, along with three other synthetic cannabinoids (AB-FUBINACA, ADB-PINACA and PB-22), into Schedule I. Over the course of a 4-month time period (July–October 2013), our laboratory quantitatively identified 5F-PB-22 in specimens obtained from four postmortem cases. We describe the four cases, to include pertinent autopsy findings and decedent histories, together with quantitative results for 5F-PB-22 determined in postmortem blood and antemortem serum. Samples were prepared via a liquid–liquid extraction at pH 10.2 into hexane : ethyl acetate. Instrumental analysis was achieved with liquid chromatography coupled with electrospray ionization tandem mass spectrometry operating in multiple reaction monitoring mode. Two ion transitions were monitored for the analyte of interest, and one ion transition was monitored for the internal standard. The observed concentration range of 5F-PB-22 is 1.1–1.5 ng/mL for three postmortem blood specimens and one antemortem serum specimen. Three of the decedents experienced abrupt, sudden death; however, one decedent expired after a rapidly deteriorating hospital course