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The football player and the infinite series  [PDF]
Harold P. Boas
Mathematics , 1997,
Abstract: This is the text of an expository talk given at the May 1997 Detroit meeting of the American Mathematical Society. It is a tale of a famous football player and a subtle problem he posed about the uniform convergence of Dirichlet series. Hiding in the background is the theory of analytic functions of an infinite number of variables.
Study on human chondrocyte culture viability for autologous transplantation in clinical application  [PDF]
Christiane Lombello,Geraldo Marins dos Reis Jr,Moisés Cohen
Einstein (S?o Paulo) , 2003,
Abstract: Objective: The limited regenerative capacity of the cartilage tissuemakes the treatment of chondral lesions difficult. The techniquescurrently available to treat cartilage lesions may relieve symptoms,but do not regenerate the injured tissue. Autologous chondrocytetransplantation uses cell biology and cell culture techniques toregenerate the hyaline cartilage. Methods: In this study, we analyzechondrocyte biopsy collection and culture for autologoustransplantation. Ultrastructural analyses of hyaline cartilage biopsieswere performed 0, 6, 24 and 48 hours after collection. The tissue evenafter 48 hours. Eleven cell culture assays were performed to evaluateisolation, viability, morphology, proliferation and absence ofcontaminants. Results: The cell culture techniques used allowedchondrocyte proliferation. Rates on cell viability were maintained abovethe acceptable patterns (above 90). Control of cell culture laboratoryconditions showed absence of contaminants, assuring safety of theprocess. The chondrocytes obtained presented the morphology typicalof cultured cell monolayers. Conclusion: The results indicate viabilityof chondrocyte culture technique for clinical application in autologoustransplantation.
Evaluation of microfracture of traumatic chondral injuries to the knee in professional football and rugby players
Masoud Riyami, Christer Rolf
Journal of Orthopaedic Surgery and Research , 2009, DOI: 10.1186/1749-799x-4-13
Abstract: To evaluate the short-term outcome of microfractured lesions in professional football ad rugby players in terms of healing and ability to return to play.Twenty-four consecutive professional male players with isolated full-thickness articular cartilage defects on weight-bearing surface of femoral condyles were treated with microfracture. Clinical assessment of healing was done at three, six, 12 and at 18 months by using modified Cincinnati subjective and objective functional scoring. All 24 subjects were periodically scanned by 3-Tesla MRI on the day of the clinical evaluations and scored by the Henderson MRI classification for cartilage healing. A second look arthroscopy was carried out in 10 players five to seven months after surgery to evaluate lesion healing by using ICRS scoring system. This was done due to presence of discrepancy between a "normal" MRI and persistent clinical symptoms.This study showed that 83.3% of players' resume full training between five to seven months (mean: 6.2) after microfracture of full-thickness chondral lesions of weight-bearing surface of the knee. Function and MRI knee scores of the 24 subjects gradually improved over 18 months, and showed good correlation in assessing healing after microfracture at six, 12 and 18 months (r2 = 0.993, 0.986 and 0.993, respectively) however, the second look arthroscopy score proved to have stronger strength of association with function score than MRI score.We confirmed that microfracture is a safe and effective procedure in treating isolated traumatic chondral lesions of the load-bearing areas of the knee. Healing as defined by subjective symptoms and evaluated by MRI and a modified knee function score occurred between 5 to 7 months in most cases, which is a reasonable absence period for the majority of players to resume their normal sports activity without risking contracts and careers. MRI correlated well with the functional knee score, but neither of these methods were totally reliable in confirm
Gel-type autologous chondrocyte (Chondron?) implantation for treatment of articular cartilage defects of the knee
Nam-Yong Choi, Byoung-Woo Kim, Woo-Jin Yeo, Haeng-Boo Kim, Dong-Sam Suh, Jin-Soo Kim, Yoon-Sik Kim, Yong-Ho Seo, Jea-Yeong Cho, Chung-Woo Chun, Hyun-Shin Park, Asode Shetty, Seok-Jung Kim
BMC Musculoskeletal Disorders , 2010, DOI: 10.1186/1471-2474-11-103
Abstract: Data from 98 patients with articular cartilage injury of the knee joint and who underwent Chondron? implantation at ten Korean hospitals between January 2005 and November 2008, were included and were divided into two groups based on the patient follow-up period, i.e. 13~24-month follow-up and greater than 25-month follow-up. The telephone Knee Society Score obtained during telephone interviews with patients, was used as the evaluation tool.On the tKSS-A (telephone Knee Society Score-A), the score improved from 43.52 ± 20.20 to 89.71 ± 13.69 (P < 0.05), and on the tKSS-B (telephone Knee Society Score-B), the score improved from 50.66 ± 20.05 to 89.38 ± 15.76 (P < 0.05). The total improvement was from 94.18 ± 31.43 to 179.10 ± 24.69 (P < 0.05).Gel-type autologous chondrocyte implantation for chondral knee defects appears to be a safe and effective method for both decreasing pain and improving knee function.As articular cartilage has only limited ability to regenerate, many treatment modalities have been developed during the past several decades to treat symptomatic articular cartilage injuries [1]. Among these treatment modalities, autologous chondrocyte implantation (ACI) has become a standard technique used to repair symptomatic, full-thickness, chondral injuries [2-4].The traditional ACI technique involves injection of cultured autologous cartilage cells into the prepared cartilage defect which is covered by a periosteal flap. The technique requires extensive surgical exposure in order for the sutures to be watertight as well as an additional incision for harvesting the periosteum. In addition, cell leakage, graft detachment, and graft hypertrophy are recognized as potential problems [5].To solve the periosteum-associated problems, many biomaterials have also been used for a new generation of ACI techniques in which cells are combined with bioactive, resorbable biomaterials such as collagen membrance [6], hyaluronan polymer [7], and copolymers of polylactin and pol
Treatment of posttraumatic and focal osteoarthritic cartilage defects of the knee with autologous polymer-based three-dimensional chondrocyte grafts: 2-year clinical results
Christian Ossendorf, Christian Kaps, Peter C Kreuz, Gerd R Burmester, Michael Sittinger, Christoph Erggelet
Arthritis Research & Therapy , 2007, DOI: 10.1186/ar2180
Abstract: Cartilage has a low intrinsic regenerative and reparative capacity. Cartilage defects may be accompanied by pain, immobility, stiffness, and loss of quality of life, and can potentially lead to severe osteoarthritis in the long term. Because chondral lesions of the knee occur frequently and are a great health problem, several efforts were made to develop techniques for restoration of the cartilage surface and regeneration of the cartilage [1]. These common repair techniques comprise debridement, bone marrow-stimulating techniques, osteochondral grafting, and autologous chondrocyte implantation (ACI) [2-5]. Some of these techniques may be useful only for small defects [6], whereas others merely provide limited durability of the repair tissue [7,8]. Using the cell-based approach of ACI, such disadvantages were not reported [9,10].Since the clinical introduction of ACI by Brittberg and colleagues [2], more than 15,000 patients worldwide have been treated with ACI [11] and a variety of clinical studies have documented the clinical effectiveness of implanting autologous culture-expanded chondrocytes for the regeneration of cartilage [9,12-14]. ACI involves the use of a periosteal flap or a collagen sheet [15], which is fixed to the surrounding cartilage and creates a reservoir for the injection of the autologous chondrocyte cell suspension. The use of ACI may therefore be delicate or even impossible in some regions of the knee. In ACI, the fixation of the periosteal flap or collagen sheets covering the chondrocyte suspension may be insecure, especially in degenerative defects lacking an intact cartilage rim. In addition, periosteal hypertrophy, ablation, uneven cell distribution, and loss of cells into the joint cavity may be potential sources of complications [16,17] resulting in repetition of surgery in up to 25 to 36% of the patients [15,18].Recently, to overcome the intrinsic technical disadvantages of ACI, cartilage tissue engineering grafts were developed that use
Autologous chondrocyte implantation to treat femoral condyle and talar lesions
Moises Cohen,Caio Nery,Maria Stella Peccin,Cibele Ramos Réssio
Einstein (S?o Paulo) , 2008,
Abstract: Objective: To show the first Brazilian autologous chondrocyteimplantation. Methods: Young patients with localized lesions infemoral condyle and talus were selected. The clinical evaluationwas complemented with the imaginologic resources. Results: Theneoformed cartilage tissue occupies the defect. The patients showedimprove in the quality life, returning to the daily and sport activities. Conclusions: It was possible to concluded that the autologous chondrocyte implantation is a promising technique for the treatment of femoral condyle and talar condral lesions.
Combined autologous chondrocyte implantation (ACI) with supra-condylar femoral varus osteotomy, following lateral growth-plate damage in an adolescent knee: 8-year follow-up
Sridhar Vijayan, George Bentley
Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology , 2011, DOI: 10.1186/1758-2555-3-5
Abstract: Injury to long bones in the lower extremities with involvement of the pyseal growth-plate is common in children and adolescents [1]. It is estimated that 15% of all long bone injuries during childhood involve the physeal growth-plate [2]. Chondral damage to the knee is common and retrospective reviews of large numbers of arthroscopic procedures have shown a prevalence of between 63% to 67% of focal chondral or osteochondral lesions [3,4]. Breakdown of articular cartilage secondary to trauma or disease results in severe pain and disability, ultimately progressing to early onset osteoarthritis [5,6]. The use of corrective high tibial osteotomy [7-9] and chondrocyte transplantation [10-12] for the treatment of isolated unicompartmental osteochondral defects of the knee are both well-described separately, as are the benefits of restoration of the mechanical axis of the knee prior to or in conjunction with chondrocyte transplantation to protect the graft site in a fully mobile knee [7,13]. The use of combined techniques for cartilage repair is becoming commoner, especially in younger patients [Parratt MTR et al: Chondrocyte transplantation combined with high tibial osteotomy in the treatment of osteochondral defects in the adolescent knee. 2011 Submitted].In this case distal femoral supracondylar osteotomy, to correct a valgus deformity at the knee caused by presumed trauma-related physeal arrest and subsequent dysplasia of the lateral femoral condyle was performed following ACI for a large 4 cm × 5 cm osteochondral defect.A 15 year-old male presented to his local Orthopaedic outpatient department complaining of a swollen painful right knee. A keen rugby player, he had also sustained an injury three months previously whilst skiing, and at the time of presentation complained of persistent pain, which had prevented him engaging in any further sporting activity. Plain radiographs confirmed the diagnosis of a stable osteochondral defect in the lateral femoral condyle. Eight
Autologous chondrocyte implantation for cartilage repair: monitoring its success by magnetic resonance imaging and histology
Sally Roberts, Iain W McCall, Alan J Darby, Janis Menage, Helena Evans, Paul E Harrison, James B Richardson
Arthritis Research & Therapy , 2002, DOI: 10.1186/ar613
Abstract: There is a burgeoning interest in cartilage repair worldwide, with particular focus on tissue engineering and cell-based therapies. While much effort goes into developing novel culture conditions and support mechanisms or scaffolds, autologous chondrocyte implantation (ACI) [1] remains the most commonly used cell-based therapy for the treatment of cartilage defects in young humans [2-4], although no randomised trials have been completed as yet [5]. Objective measures of the properties of the grafted regions are necessary for long-term follow-up of this procedure and to evaluate how closely the treated region resembles normal articular cartilage. Useful outcome measures that assess the overall function, structure, and composition of chondral tissue [6] include mechanical properties or its appearance in arthroscopy, histology, and magnetic resonance imaging (MRI), in addition to clinical assessment of the patient. However, there has been little standardisation of such outcome measures [7]. We have therefore developed histological and MRI scoring schemes and used them to assess the quality of repair tissue at varying time points up to 34 months after the grafting procedure. In addition, immunohistochemistry has been used to assess whether the tissue in the grafted site resembled normal articular cartilage, not only in its matrix organisation but also in its chemical composition.Cartilage function reflects its biochemical composition [8]. A small biopsy specimen such as is used for histochemical assessment can provide only limited information, as it is from a discrete location. MRI, in contrast, can provide information on the whole area. In addition, it is noninvasive and successive scans can be carried out, so allowing longitudinal monitoring at different time points. MR images have been shown to correlate with biochemical composition in other tissues, in cartilage in vivo, and even in engineered cartilage generated in a bioreactor [9-11]. Thus in this study we have us
Autologous chondrocyte implantation for rheumatoid arthritis of the knee: a case report
Seok-Jung Kim, Cheong-Ho Chang, Dong-Sam Suh, Hyun-Kwon Ha, Kyung-Hwan Suhl
Journal of Medical Case Reports , 2009, DOI: 10.1186/1752-1947-3-6619
Abstract: We treated rheumatoid arthritis of the right knee in a 35-year-old female Korean patient using autologous chondrocyte implantation. Twelve months after surgery, the patient could walk without pain.Autologous chondrocyte implantation appears to be effective for treating rheumatoid arthritis of the knee.Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints. To date, pharmacologic treatment remains the primary form of treatment, however, if pain and limitation of joint function become severe and debilitating, surgical treatment should be considered [1]. Over the last few decades, artificial joint replacement techniques have developed very rapidly and many arthritic conditions have thus been successfully treated [2]. However, as total joint arthroplasty is not permanent, in some cases, revisional surgery is inevitable, especially for young patients [3]. Therefore, there is an ever-increasing need for a method that biologically regenerates the arthritic lesion of the knee as patient longevity continually increases. This report presents the case of a 35-year-old woman with a painful, arthritic knee and her treatment using autologous chondrocyte implantation (ACI).A 35-year-old Korean woman with RA was admitted for right knee joint pain. Plain radiographs (Figure 1a) revealed progression of arthritis with lateral joint space narrowing when compared with radiographs obtained 4 years previously. The patient refused total joint replacement arthroplasty which our medical staff recommended and requested ACI. Knee arthroscopy was then performed to harvest 200g of autologous cartilage from the intercondylar notch (Figure 1b,c). The cartilage fragment was sent to a commercial cell culturing facility (SewonCellontech, Seoul) for processing.Autologous chondrocyte implantation was performed 6 weeks after her initial surgery when 48 × 106 chondrocytes had been cultured. Autologous chondrocytes were aseptically processed, suspended in sterile
Knee chondral lesions treated with autologous chondrocyte transplantation in a tridimensional matrix: clinical evaluation at 1-year follow-up
Félix Vilchez,Jorge Lara,Eduardo álvarez-Lozano,Carlos E. Cuervo,Oscar F. Mendoza,Carlos A. Acosta-Olivo
Journal of Orthopaedics and Traumatology , 2009, DOI: 10.1007/s10195-009-0069-z
Abstract: These results indicate that our tridimensional matrix technique effectively improved patients’ quality of life, at least in the short term, and delayed any subsequent procedure. Long-term assessment is necessary to determine the true value of this technique.
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