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

Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel

<p>Abstract</p> <p>Background</p> <p>Functional repair of articular osteochondral defects remains a major challenge not only in the field of knee surgery but also in tissue regeneration medicine. The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN) gel at the bottom of the defect.</p> <p>Methods</p> <p>Twenty-five mature rabbits were used in this study. In the bilateral knees of each animal, we created an osteochondral defect having a diameter of 2.4-mm in the medial condyle. Then, in 21 rabbits, we implanted a DN gel plug into a right knee defect so that a vacant space of 1.5-mm depth (in Group I), 2.5-mm depth (in Group II), or 3.5-mm depth (in Group III) was left. In the left knee, we did not apply any treatment to the defect to obtain the control data. All the rabbits were sacrificed at 4 weeks, and the gross and histological evaluations were performed. The remaining 4 rabbits underwent the same treatment as used in Group II, and real-time PCR analysis was performed at 4 weeks.</p> <p>Results</p> <p>The defect in Group II was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen. The Wayne's gross appearance and histology scores showed that Group II was significantly greater than Group I, III, and Control (p < 0.012). The relative expression level of type-2 collagen, aggrecan, and SOX9 mRNAs was significantly greater in Group II than in the control group (p < 0.023).</p> <p>Conclusions</p> <p>This study demonstrated that spontaneous hyaline cartilage regeneration can be induced <it>in vivo </it>in an osteochondral defect created in the femoral condyle by means of implanting the DN gel plug at the bottom of the defect so that an approximately 2-mm deep vacant space was intentionally left in the defect. This fact has prompted us to propose an innovative strategy without cell culture to repair osteochondral lesions in the femoral condyle.</p

Management of work-relevant upper limb disorders: a review

Background Upper limb disorders (ULDs) are clinically challenging and responsible for considerable work loss. There is a need to determine effective approaches for their management. Aim To determine evidence-based management strategies for work-relevant ULDs and explore whether a biopsychosocial approach is appropriate. Methods Literature review using a best evidence synthesis. Data from articles identified through systematic searching of electronic databases and citation tracking were extracted into evidence tables. The information was synthesized into high-level evidence statements, which were ordered into themes covering classification/diagnosis, epidemiology, associations/risks and management/treatment, focusing on return to work or work retention and taking account of distinctions between non-specific complaints and specific diagnoses. Results Neither biomedical treatment nor ergonomic workplace interventions alone offer an optimal solution; rather, multimodal interventions show considerable promise, particularly for occupational outcomes. Early return to work, or work retention, is an important goal for most cases and may be facilitated, where necessary, by transitional work arrangements. The emergent evidence indicates that successful management strategies require all the players to be onside and acting in a coordinated fashion; this requires engaging employers and workers to participate. Conclusions The biopsychosocial model applies: biological considerations should not be ignored, but psychosocial factors are more influential for occupational outcomes. Implementation of interventions that address the full range of psychosocial issues will require a cultural shift in the way the relationship between upper limb complaints and work is conceived and handled. Dissemination of evidence-based messages can contribute to the needed cultural shift

Trauma induces apoptosis in human thoracolumbar intervertebral discs

BACKGROUND: Vertebral fractures resulting from high energy trauma often comprise the risk of posttraumatic degenerative changes in the affected intervertebral discs (IVD). Particularly in conservatively treated patients, or in cases after implant removal of an exclusively posterior stabilization, consecutive disc degeneration and the associated functional losing of the spinal segment clearly represent detrimental treatment results. In this regard, apoptosis of IVD cells has been suggested to be involved in the critical changes of the extracellular matrix. METHODS: To investigate whether fractures of the vertebrae induce apoptosis in the affected IVD, disc tissue from patients (n = 17) undergoing open reduction and internal fixation of thoracolumbar spine fractures were analysed in regards to caspase activity, apoptosis-receptor expression levels and gene expression of apoptosis-regulating proteins such as Bax and Bcl-2. Healthy IVD tissue (n = 3) obtained from patients undergoing surgical resection of adjacent vertebrae were used as control samples. RESULTS: In contrast to healthy control IVD tissues, samples from traumatic thoracolumbar IVD showed positive TUNEL staining and a significant increase of caspase-3/7 activity. Interestingly, analyses of the initiator caspase-8 and -9 revealed significantly increased activation levels compared to control values, suggesting the coexistent activation of both the extrinsic (receptor-mediated) and intrinsic (mitochondria-mediated) apoptosis pathway. Accordingly, expression levels of the Fas receptor (FasR) mRNA were significantly increased. Although the TNF receptor I (TNFR I) was only slightly upregulated, corresponding TNFα from trauma IVD presented significantly increased mRNA expression values. Furthermore, traumatic IVD cells demonstrated significantly reduced expression of the mitochondria-bound anti-apoptotic Bcl-2, thereby maintaining baseline transcriptional levels of the pro-apoptotic Bax protein when compared to control IVD cells. CONCLUSION: Our data suggest that thoracolumbar fractures induce early caspase-dependent apoptosis in IVD cells of the affected intervertebral disc, in part, by downregulation of the anti-apoptotic protein Bcl-2 (intrinsic apoptosis pathway), as well as signalling via the death receptor complex (TNFR I and FasR)

Association of alpha1a-adrenergic receptor polymorphism and blood pressure phenotypes in the Brazilian population

Background: The alpha1A-adrenergic receptor (alpha(1A)-AR) regulates the cardiac and peripheral vascular system through sympathetic activation. Due to its important role in the regulation of vascular tone and blood pressure, we aimed to investigate the association between the Arg347Cys polymorphism in the alpha(1A)-AR gene and blood pressure phenotypes, in a large sample of Brazilians from an urban population. Methods: A total of 1568 individuals were randomly selected from the general population of the Vitoria City metropolitan area. Genetic analysis of the Arg347Cys polymorphism was conducted by polymerase chain reaction/restriction fragment length polymorphism. We have compared cardiovascular risk variables and genotypes using ANOVA, and Chi-square test for univariate comparisons and logistic regression for multivariate comparisons. Results: Association analysis indicated a significant difference between genotype groups with respect to diastolic blood pressure (p = 0.04), but not systolic blood pressure (p = 0.12). In addition, presence of the Cys/Cys genotype was marginally associated with hypertension in our population (p = 0.06). Significant interaction effects were observed between the studied genetic variant, age and physical activity. Presence of the Cys/Cys genotype was associated with hypertension only in individuals with regular physical activity (odds ratio = 1.86; p = 0.03) or younger than 45 years (odds ratio = 1.27; p = 0.04). Conclusion: Physical activity and age may potentially play a role by disclosing the effects of the Cys allele on blood pressure. According to our data it is possible that the Arg347Cys polymorphism can be used as a biomarker to disease risk in a selected group of individuals.FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[2001/03454-5

An empirical approach towards the efficient and optimal production of influenza-neutralizing ovine polyclonal antibodies demonstrates that the novel adjuvant CoVaccine HT(TM) is functionally superior to Freund's adjuvant

Passive immunotherapies utilising polyclonal antibodies could have a valuable role in preventing and treating infectious diseases such as influenza, particularly in pandemic situations but also in immunocompromised populations such as the elderly, the chronically immunosuppressed, pregnant women, infants and those with chronic diseases. The aim of this study was to optimise current methods used to generate ovine polyclonal antibodies. Polyclonal antibodies to baculovirus-expressed recombinant influenza haemagglutinin from A/Puerto Rico/8/1934 H1N1 (PR8) were elicited in sheep using various immunisation regimens designed to investigate the priming immunisation route, adjuvant formulation, sheep age, and antigen dose, and to empirically ascertain which combination maximised antibody output. The novel adjuvant CoVaccine HT™ was compared to Freund’s adjuvant which is currently the adjuvant of choice for commercial production of ovine polyclonal Fab therapies. CoVaccine HT™ induced significantly higher titres of functional ovine anti-haemagglutinin IgG than Freund’s adjuvant but with fewer side effects, including reduced site reactions. Polyclonal hyperimmune sheep sera effectively neutralised influenza virus in vitro and, when given before or after influenza virus challenge, prevented the death of infected mice. Neither the age of the sheep nor the route of antigen administration appeared to influence antibody titre. Moreover, reducing the administrated dose of haemagglutinin antigen minimally affected antibody titre. Together, these results suggest a cost effective way of producing high and sustained yields of functional ovine polyclonal antibodies specifically for the prevention and treatment of globally significant diseases.Natalie E. Stevens, Cara K. Fraser, Mohammed Alsharifi, Michael P. Brown, Kerrilyn R. Diener, John D. Haybal

The influence of the representation of collagen fibre organisation on the cartilage contact mechanics of the hip joint

The aim of this study was to develop a finite element (FE) hip model with subject-specific geometry and biphasic cartilage properties. Different levels of detail in the representation of fibre reinforcement were considered to evaluate the feasibility to simplify the complex depth-dependent fibre pattern in the native hip joint. A FE model of a cadaveric hip with subject-specific geometry was constructed through micro-computed-tomography (µCT) imaging. The cartilage was assumed to be biphasic and fibre-reinforced with different levels of detail in the fibre representation. Simulations were performed for heel-strike, mid-stance and toe-off during walking and one-leg-stance over 1500s. It was found that the required level of detail in fibre representation depends on the parameter of interest. The contact stress of the native hip joint could be realistically predicted by simplifying the fibre representation to being orthogonally reinforced across the whole thickness. To predict the fluid pressure, depth-dependent fibre organisation is needed but specific split-line pattern on the surface of cartilage is not necessary. Both depth-dependent and specific surface fibre orientations are required to simulate the strains

Differentiated thyroid carcinoma in children and adolescents

From 1936 to 1990, 89 children and adolescents (72 girls and 17 boys) were treated for differentiated thyroid carcinoma at the University of Michigan Medical Center; 58 of these patients were first reported in 1971. Thirty (34%) patients had previously received external irradiation to the head and neck, although only 1 (3%) patient of the last 33 patients seen had this history. Patients first presenting from 1971 to 1990 had less advanced disease than those seen earlier. Also, during this time period, the rate of initial palpable cervical adenopathy fell from 63% to 36%, local infiltration of primary cancer from 31% to 6%, and initial pulmonary metastases from 19% to 6%. The incidence of cervical nodal metastases has remained 88% for 54 years. Papillary or the follicular variant of papillary carcinoma was found in 93% of all patients. Seventy-nine (89%) patients had total or completion total thyroidectomy. Surgical management of lymphatic metastases varied from regional excision of nodes to radical neck dissection. The overall rate of permanent accidental recurrent laryngeal nerve palsy and hypoparathyroidism was 4.5%, although neither has occurred in a child or adolescent undergoing surgery at the center in the past 25 years. The most recent 33 patients had a low rate of local/regional persistence or recurrence. Cervical nodal persistence occurred in 21%; there were no thyroid recurrences. Eighty-two percent of patients received 131 I. The long-term mortality rate was 2.2%. We continue to advocate total thyroidectomy, cervical lymph node dissection, and postoperative 131 I therapy as the most conservative treatment regimen for children with differentiated thyroid carcinoma. Entre 1936 et 1990, 89 enfants et adolescents (72 filles et 17 garons) ont été traités pour cancer différencie de la thyroïde au Centre Médical de l'Université de Michigan. Cinquante huit d'entre eux ont fait l'objet d'une publication en 1971. Trente de ces patients (34%) avaient eu une radiothérapie externe au niveau de la tête et/ou du cou, mais ce facteur n'a été retrouvé que chez un des 33 derniers patients (3%). Les patients vus entre 1971 et 1990 avaient une maladie moins avancée. Pendant cette période, le taux d'adénopathies cervicales palpables est passée de 63 à 36%; le pourcentage de patients ayant une infiltration locale, de 31 à 6%, et celui de métastases pulmonaires de 19 à 6%. L'incidence des métastases ganglionnaires cervicales, par contre, est restée de 88% depuis 54 ans. Le cancer était papillaire ou folliculaire dans 93% des cas. Soixante-neuf patients (89%) ont eu une thyroïdectomie totale, soit d'embl%ee soit secondairement. La thérapeutique des métastases ganglionnaires a varié depuis l'exérèse régionale et le curage ganglionnaire cervical. Le taux global de paralysie récurrentielle et de l'hypoparathyroïde était de 4.5%, mais aucune de ces deux complications n'a été observée pour les enfants opérés dans notre centre au cours des 25 dernières années. Parmi les 33 derniers patients, le taux de tissu résiduel ou de récidive était bas. Dans 21% des cas, il persistait du tissu néoplasique après chirurgie, sans récidive. Quatre-vingt pour cent de ces patients ont eu un traitement par l'iode 131. La mortalité à distance était de 2.2%. Nous continuous de recommander une thyroïdectomie totale, une lymphadénectomie cervicale et une iodothérapie post-opératoire par l'iode 131 comme le traitement les plus conservateurs du cancer différencié de la thyroïde chez l'enfant. Ochenta y nueve niños y adolescentes (72 de sexo femenino y 17 de sexo masculino) fuiron tratados por carcinoma tiroideo diferenciado en el Centro Médico de la Universidad de Michigan; 58 de estos pacientes fueron reportados por primera vez en 1971. Treinta pacientes (34%) tenían historia de irradiación a la cabeza y el cuello; sin embargo, solamente uno de los últimos 33 (3%) presentó tal historia. Los pacientes vistos entre 1971 y 1990 exhibían enfermedad menos avanzada que aquellos vistos previamente. Así mismo, la incidencia de adenopatías cervicales palpables descendió de 63% a 36%, la de infiltración local por cáncer primario de 31% a 6% y la de metástasis pulmonares iniciales de 19% a 6%. La incidencia de metástasis ganglionares cervicales se ha mantenido en 88% por 54 años. La variante papilar o folicular del carcinoma papilar se encontró en 93% de los pacientes de la serie. Setenta y nueve pacientes (89%) fueron sometidos a toroidectomía total o a reoperación para completar la tiroidectomía total. El manejo quirúrgico de las metástasis linfáticas varió desde la resección regional de los ganglios hasta la disección radical del cuello. La tasa global de lesión accidental, permanente o temporal, del nervio recurrente laríngeo y de hopoparatiroidismo fue 4.5%, aunque ninguna de estas complicaciones ha ocurrido en un niño o en un adolescente sometido a cirugía en nuestro centro médico en los últimos 25 años. Los últimos 33 pacientes exhibieron una tasa reducida de persistencia o de recurrencia local/regional. La persistencia ganglionar cervical se presentó en 21% de los casos; no hubo recurrencias tiroideas. Ochenta y dos por ciento de los pacientes recibió 131 I. La tassa de mortalidad a largo plazo fui 2.2%. Nuestro grupo continúa preconizando tiroidectomía total, disección ganglionar cervical y terapia postoperatoria con 131 I como la modalidad terapéutica más conservadora en carcinoma diferenciado de la glándula tiroidea en la niñez.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41290/1/268_2005_Article_BF02067317.pd