In Vitro and Ectopic In Vivo Studies toward the Utilization of Rapidly Isolated Human Nasal Chondrocytes for Single-Stage Arthroscopic Cartilage Regeneration Therapy

Nasal chondrocytes (NCs) have a higher and more reproducible chondrogenic capacity than articular chondrocytes, and the engineered cartilage tissue they generate in vitro has been demonstrated to be safe in clinical applications. Here, we aimed at determining the feasibility for a single-stage application of NCs for cartilage regeneration under minimally invasive settings. In particular, we assessed whether NCs isolated using a short collagenase digestion protocol retain their potential to proliferate and chondro-differentiate within an injectable, swiftly cross-linked and matrix-metalloproteinase (MMP)-degradable polyethylene glycol (PEG) gel enriched with human platelet lysate (hPL). NC-hPL-PEG gels were additionally tested for their capacity to generate cartilage tissue in vivo and to integrate into cartilage/bone compartments of human osteochondral plugs upon ectopic subcutaneous implantation into nude mice. NCs isolated with a rapid protocol and embedded in PEG gels with hPL at low cell density were capable of efficiently proliferating and of generating tissue rich in glycosaminoglycans and collagen II. NC-hPL-PEG gels developed into hyaline-like cartilage tissues upon ectopic in vivo implantation and integrated with surrounding native cartilage and bone tissues. The delivery of NCs in PEG gels containing hPL is a feasible strategy for cartilage repair and now requires further validation in orthotopic in vivo models. Keywords: cartilage regeneration; autologous chondrocyte implantation; nasal chondrocytes; single-stage; arthroscopy; tissue engineering; polyethylene glycol; hydrogel; platelet lysat

Технологические решения для строительства разведочной вертикальной скважины глубиной 3130 метров на газовом месторождении (Томская область)

Объектом исследования работы является месторождение Томской области. Целью работы является – спроектировать технологическое решения для бурения вертикальной разведочной скважины, геолого-технический наряд, компоновки низа бурильной колонны, интервалы бурении и спуск обсадных колонн, интервалы цементирования. Все технологические решения для строительства скважины приняты с учетом современных достижений в области технологии и техники строительства скважины.The object of research is a Deposit in the Tomsk region. The aim of the work is to design technological solutions for drilling vertical exploration wells, geological engineering outfits, bottom hole assembly, drilling intervals and casing descent, cementing intervals. All technological solutions for the well are given taking into account modern achievements in the field of engineering and technology of well construction

Alite calcium sulfoaluminate cement: chemistry and thermodynamics

Calcium sulfoaluminate (C$A) cement is a binder of increasing interest to the cement industry and is undergoing rapid development. Current formulations do not contain alite; however, alite calcium sulfoaluminate (a-C$A) cements can combine the favourable characteristics of Portland cement (PC) with those of C$A cement while also having a lower carbon dioxide footprint than the current generation of PC clinkers. This paper presents two results on the formation of a-C$A clinkers. The first is a thermodynamic study demonstrating that the production of a-C$A clinker is possible without the use of mineralisers, doping with foreign elements, or using multiple stages of heating. It is established that a-C$A clinker can be readily produced in a standard process by controlling the oxygen and sulfur dioxide fugacity in the atmosphere. This allows for the stabilisation of ye’elimite to the higher temperatures required for alite stability. The second result establishes that when using fluorine to mineralise a-C$A clinker production, the iron content in the clinker is also an important variable. Although the exact mechanism of alite stabilisation is not known, it is shown that alite formation increases with the combination of calcium fluoride and iron (III) oxide in the mix

Discordant findings in color-coded duplex-sonography and magnetic resonance angiography in symptomatic internal carotid artery stenosis: implications for diagnostic work-up and early intervention

Background: Magnetic resonance angiography (MRA) is supposed to be the new ’gold standard’ in the diagnosis of atherosclerotic disease of the extracranial arteries. Methods: A case report is presented on a patient in whom discordant findings of the status of the left internal carotid artery (ICA) were identified in color-coded duplex-sonography and MRA. Results: Left ICA stenosis was suspected in duplex-sonography, yet not confirmed in contrast-enhanced (CE) MRA reconstruction. Diagnosis was confirmed after surgery and in subsequent analysis of the original CE-MRI data. Conclusions: The analysis of source images must not be missed in MRA examinations. Conventional duplex-sonography may be superior in the estimation of the embolic potential of vascular lesions. Advanced CE techniques may therefore be adequate tools in differentiating patients eligible for carotid endarterectomy (CEA) or carotid stenting, avoiding the risk of peri-interventional iatrogenic complications. It should urgently be further improved and validated

Does patella alta lead to worse clinical outcome in patients who undergo isolated medial patellofemoral ligament reconstruction? A systematic review

Introduction: The aim of this systematic review is to determine the effect of patella height on clinical outcomes after isolated MPFL reconstruction for patella instability. Our primary hypothesis is that patients with patella alta report similar outcomes after isolated MPFL reconstruction compared to patients with normal patella height. Methods: A review of the literature was performed according to the PRISMA guidelines. PubMed, EMBASE, and the Cochrane Library were searched from inception to January 10th 2018. Studies were identified using synonyms for “medial patellofemoral ligament”, “reconstruction” and “patella alta”. Results: The search resulted in 467 reports on PubMed, 175 on EMBASE and 3 on the Cochrane Library. We included and analyzed in detail six studies describing outcomes after isolated medial patellofemoral ligament reconstruction with regard to patellar height. We found that both patients with patella alta and normal patella height reported satisfactory outcomes after isolated medial patellofemoral ligament reconstruction. However, because of applied exclusion criteria in the included studies the total number of patients with severe patella alta was small (13/74 patients with patella alta, 18%). Conclusions: Based on the current literature we suggest that additional tibial tubercle distalisation is not mandatory in patients with mild patella alta (Caton–Deschamps Index 1.2–1.4). To assess the best indications for different surgical procedures for patients with patella instability future research is needed to develop a clear and uniform definition of relevant patella alta. Level of evidence: III

Arthroscopic Treatment of Cartilage Lesions With Microfracture and BST-CarGel

Bone marrow stimulation techniques for the treatment of articular cartilage defects such as microfracture so far have solely reproduced mechanically inferior fibrous cartilage tissue, which might result in unsatisfactory clinical results at midterm follow-up. A recent study has shown an improvement in repair tissue quality by enhancing microfracture with a chitosan-based biomaterial (BST-CarGel; Piramal, Laval, Quebec, Canada). BST-CarGel so far has only been applied by arthrotomy, which might lead to increased scar tissue formation and thus compromise recovery time and clinical outcome. We describe a surgical technique for an arthroscopic treatment of cartilage defects of the knee with microfracture in combination with BST-CarGel to benefit from improved repair tissue quality and to reduce arthrotomy-related morbidity