Molecular and Cellular Mechanisms of Delayed Fracture Healing in Mmp10 (Stromelysin 2) Knockout Mice

The remodeling of the extracellular matrix is a central function in endochondral ossification and bone homeostasis. During secondary fracture healing, vascular invasion and bone growth requires the removal of the cartilage intermediate and the coordinate action of the collagenase matrix metalloproteinase (MMP)-13, produced by hypertrophic chondrocytes, and the gelatinase MMP-9, produced by cells of hematopoietic lineage. Interfering with these MMP activities results in impaired fracture healing characterized by cartilage accumulation and delayed vascularization. MMP-10, Stromelysin 2, a matrix metalloproteinase with high homology to MMP-3 (Stromelysin 1), presents a wide range of putative substrates identified in vitro, but its targets and functions in vivo and especially during fracture healing and bone homeostasis are not well defined. Here, we investigated the role of MMP-10 through bone regeneration in C57BL/6 mice. During secondary fracture healing, MMP-10 is expressed by hematopoietic cells and its maximum expression peak is associated with cartilage resorption at 14 days post fracture (dpf). In accordance with this expression pattern, when Mmp10 is globally silenced, we observed an impaired fracture-healing phenotype at 14 dpf, characterized by delayed cartilage resorption and TRAP-positive cell accumulation. This phenotype can be rescued by a non-competitive transplant of wild-type bone marrow, indicating that MMP-10 functions are required only in cells of hematopoietic linage. In addition, we found that this phenotype is a consequence of reduced gelatinase activity and the lack of proMMP-9 processing in macrophages. Our data provide evidence of the in vivo function of MMP-10 during endochondral ossification and defines the macrophages as the lead cell population in cartilage removal and vascular invasion. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).     

Characteristics and Motivation of Solid Organ Transplant Recipients Attending the Canadian Transplant Games

BackgroundThe Canadian Transplant games (“Games”) were created to increase awareness of organ donation and highlight the importance of staying active and healthy post-transplant. It is unclear what motivates solid organ transplant (SOT) recipients to participate and whether the games serve as an incentive for SOT recipients to increase their physical activity (PA) levels.Objectives1. To describe the characteristics of participants from past games and their motivation for attending and 2. to determine whether there was an interest in participating in goal-based, pre-games exercise training programs.MethodsA web-based questionnaire was sent to adult SOT recipients who were members of the Canadian Transplant Association. The survey included questions about why participants attended, their PA levels, and their interest in a pre-games training program.ResultsOf the 157 participants, more were male than female; the 35-54-year-old age group was the most common; and 62% of respondents received a liver or kidney transplant. The most common reasons for participating in the games were to showcase health post-transplant, promote awareness of organ donation, sports competition, and social reasons. Sixty-five percent of respondents reported that they would be interested in an exercise program to be more physically prepared for the competition.ConclusionPre-games training programs could be developed to motivate participation and help participants achieve higher training intensities and foster social interaction. Directing resources to individuals who do not attend the games and to those who are not physically active should be considered.     

Overview and update on molecular testing in non-small cell lung carcinoma utilizing endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples

Lung carcinoma remains one of the most frequent and aggressive human neoplasms. Fortunately, in the last decades, the increasing knowledge of the molecular mechanisms leading to cancer development has allowed the use of targeted therapies with improvement of prognosis in many patients. Clinical management has also changed after the introduction of endobronchialultrasonographic bronchoscopy that allows a conservative staging of lung tumors, avoiding the need of mediastinoscopy for lymph node staging. Lung pathologists and cytopathologists are facing the challenge of giving the more comprehensive prognostic and predictive information with ever smaller tissue or cytological samples. The aim of this review is to summarize the molecular testing for non-small cell lung carcinoma and how pathologists can contribute to the patient's outcome with a conscious management of biological samples.     

The anatomy of the anterior inferior tibiofibular ligament and its relationship with the Wagstaffe fracture

BackgroundOur aim in this study was to identify the fibular footprint of the Anterior Inferior Tibiofibular Ligament (AITFL) and its relation to Wagstaffe fracture fragment size.MethodsWe examined 25 cadaveric lower limbs which were carefully dissected to identify the lateral ankle ligaments. The AITFL anatomy was compared to 40 Wagstaffe fractures identified from our ankle fracture database.ResultsThe AITFL origin was from the anterior fibular tubercle with an average length of 21.61 mm (95% CI 20.22, 22.99). The average distance of the distal aspect of the AITFL footprint to the distal fibula margin was 11.60 mm (95% CI 10.49, 12.71). In the ankle fractures analyzed, the average length of the Wagstaffe fragment was 17.88 mm (95% CI 16.21, 19.54). The average distance from the distal tip of the fibula to the Wagstaffe fracture fragment was 21.40 mm (95% CI 19.78, 23.01).In total there were 22 syndesmosis injuries. There was no statistical difference in Wagstaffe fragment size between stable and unstable groups.ConclusionThe AITFL fibular origin was both larger and more distal than the Wagstaffe fracture fragments seen in our institution. Therefore, this suggests that a ligamentous failure will also have to occur to result in syndesmotic instability. The size of fracture fragment also did not confer to syndesmotic instability on testing.Level of Evidence - 3     

A narrative review of individualized treatments of genitourinary tumors: is the future brighter with molecular evaluations?

Few molecular prognostic and predictive biomarkers have been identified so far in genitourinary tumors. We started from a literature search to explore the status of the art of molecular pathology tests as diagnostic, prognostic, predictive biomarkers in genitourinary cancers. Next generation sequencing approaches now provide mind-changing information in the fields of kidney cancer diagnosis, predictive oncology of urothelial cancer, understanding the causes of testicular and penile cancer, and the comprehension of the drivers of prostate cancer progression beyond androgen regulation. The classification of kidney cancer will be based soon on molecular changes. The causes of non-HPV related penile cancer are largely unknown. The emerging high incidence of testicular cancer could be explained only on the basis of molecular changes. The response to novel therapeutic agents in prostatic and urothelial cancer will require thorough molecular tumor characterization. The hereditary risk of patients with early onset prostate cancer and their potential treatment with targeted therapy requires germline and somatic genetic assays. The implementation of effective biomarkers for the response to immune check-point inhibitors in genitourinary cancer is based on the assessment of inflammatory expression profiles and the tumor mutational burden. This review deals with the current tests and provides a tentative foresee of the future molecular biomarkers of genitourinary cancer.     

Characterization of the binding of [3H]-SB-204269, a radiolabelled form of the new anticonvulsant SB-204269, to a novel binding site in rat brain membranes

1. SB-204269 (trans-(+)-6-acetyl-4S-(4-fluorobenzoylamino)-3,4-dihydro-2,2-dimethyl-2H-benzol[b]pyran-3R-ol, hemihydrate) shows potent anticonvulsant activity in a range of animal seizure models, with a lack of neurological or cardiovascular side-effects. The profile of the compound suggests that it may have a novel mechanism of action. This study describes the characteristics of a binding site for [³H]-SB-204269 in rat forebrain membranes.
2. Specific [³H]-SB-204269 binding was saturable and analysis indicated binding to a homogenoeous population of non-interacting binding sites with a dissociation constant (K_D) of 32±1 nM and a maximum binding capacity (B_max) of 253±18 fmol mg⁻¹ protein. Kinetic studies indicated monophasic association and dissociation. Binding was similar in HEPES or Tris-HCl buffers and was unaffected by Na⁺, K⁺, Ca²⁺ or Mg²⁺ ions. Specific binding was widely distributed in brain, but was minimal in a range of peripheral tissues.
3. Specific [³H]-SB-204269 binding was highly stereoselective, with a 1000 fold difference between the affinities of SB-204269 and its enantiomer SB-204268 for the binding site. The affinities of analogues of SB-204269 for binding can be related to their activities in the mouse maximal electroshock seizure threshold (MEST) test of anticonvulsant action.
4. None of the standard anticonvulsant drugs, phenobarbitone, phenytoin, sodium valproate, carbamazepine, diazepam and ethosuximide, or the newer anticonvulsants, lamotrigine, vigabatrin, gabapentin and levetiracetam, showed any affinity for the [³H]-SB-204269 binding site. A wide range of drugs active at amino acid receptors, Na⁺ or K⁺ channels or various other receptors did not demonstrate any affinity for the binding site.
5. These studies indicate that SB-204269 possesses a specific CNS binding site which may mediate its anticonvulsant activity. This binding site does not appear to be directly related to the sites of action of other known anticonvulsant agents, but may have an important role in regulating neuronal excitability.

     

Use of the humanized anti-epidermal growth factor receptor monoclonal antibody h-R3 in combination with radiotherapy in the treatment of locally advanced head and neck cancer patients.

PURPOSE: To evaluate safety and preliminary efficacy of the humanized anti-epidermal growth factor receptor monoclonal antibody h-R3 in combination with radiotherapy (RT) in unresectable head and neck cancer patients. Secondary end points were the measurement of h-R3 serum levels and the assessment of the potential mechanisms of antitumor effect on patient biopsies. Anti-idiotypic response to h-R3 was assessed. To predict pharmacologic effect, a mathematical model for antibodies recognizing antigens expressed in tumors and normal tissues was built. PATIENTS AND METHODS: Twenty-four patients with advanced carcinomas of the head and neck received six once-weekly infusions of h-R3 at four dose levels in combination with RT. Pretreatment tumor biopsies were obtained to evaluate epidermal growth factor receptor expression as an enrollment criterion. Second biopsies were taken to evaluate the proliferative activity and angiogenesis in comparison with the pretreatment samples. Patient serum samples were collected to measure h-R3 levels and anti-idiotypic response. RESULTS: The combination of h-R3 and RT was well tolerated. Antibody-related adverse events consisted in infusion reactions. No skin or allergic toxicity appeared. Overall survival significantly increased after the use of the higher antibody doses. Immunohistochemistry studies of tumor specimens before and after treatment revealed that antitumor response correlated with antiproliferative and antiangiogenic effect. One patient developed antibodies to h-R3. The mathematical model predicted that the maximum difference between the area under the curve in tumors and normal tissues is reached when the antibody has intermediate affinity. CONCLUSION: h-R3 is a well-tolerated drug that may enhance radiocurability of unresectable head and neck neoplasms.