Application of Nondegradable Synthetic Materials for Tendon and Ligament Injury

Tendon and ligament injuries, prevalent requiring surgical intervention, significantly impact joint stability and function. Owing to excellent mechanical properties and biochemical stability, Nondegradable synthetic materials, including polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE), have demonstrated significant potential in the treatment of tendon and ligament injuries. These above materials offer substantial mechanical support, joint mobility, and tissue healing promotion of the shoulder, knee, and ankle joint. This review conclude the latest development and application of nondegradable materials such as artificial patches and ligaments in tendon and ligament injuries including rotator cuff tears (RCTs), anterior cruciate ligament (ACL) injuries, and Achilles tendon ruptures.     

Thermal analysis of the osteoarthritic human hyaline cartilage

Summary Arthritis of major joints, especially osteoarthritis of the knee is a very frequent disease of human beings mainly in the developed countries. The pathology of osteoarthritis has been subject of many publications before, using a wide spectrum of different methods to evaluate degenerative changes of hyaline cartilage. The authors examined osteoarthritic human knee joint hyaline cartilage with differential scanning calorimetry. The different stages of cartilage degeneration have been verified by histological examinations. The research group demonstrated thermal differences between various stages of osteoarthritis. Besides explaining possible causes for experienced thermodynamic effects, the authors reflect upon future research ways and the possibilities of applying the method in practice.     

Comparison of thermal characteristics of degenerated and inflamed human collagen structures with differential scanning calorimetry

Collagen is the primary structural protein of the human body and the main component of connective tissue. In the form of elongated fibrils, collagen is mostly found in fibrous tissues such as tendon, ligament, and skin. We have already demonstrated that pathologic changes of human collagen structures could be monitored by differential scanning calorimetry (DSC), besides the classical histological methods. The aim of the study was to find whether there is a consistent increase or decrease of the thermal parameters, if we compare the changes of calorimetric enthalpy and denaturation temperature of (1) group: degenerative with (2) group: inflamed collagen structures. The degenerative samples were collected from ruptured Quadriceps, Achilles, patellar and anterior cruciate ligament, and degenerated joint capsule of the shoulder. The inflamed tissue samples were collected from palmar aponeurosis in Dupuytren disease, transverse carpal ligament in carpal tunnel syndrome (CTS), and transverse ligament of the first dorsal compartment in De Quervain disease. The thermal denaturation of human samples was monitored by a SETARAM Micro DSC-II calorimeter. All the experiments were performed between 0 and 100 °C. The heating rate was 0.3 K min^?1. DSC scans clearly demonstrated significant differences between the two groups, proving that the thermal stability of the degenerative and inflamed pathologic collagens is significantly different. In cases of degenerative samples, the enthalpy decreased, while the melting temperature showed an increase. On the contrary, inflamed samples demonstrated a significant increase in the enthalpy and the melting temperature decreased. Our results indicate that DSC may be a clinically relevant method in the diagnosis of different collagen diseases.     

DSC examination of the rotator cuff muscles in rabbits

Rotator cuff tear is a common musculoskeletal disorder with pathological changes occurring in the structure of the rotator cuff musculature (fatty infiltration). Severe fatty infiltration, observed on MRI or CT scan, negatively influences the result of rotator cuff reconstruction in human beings. The basic histological and biochemical alterations in fatty infiltration of the rotator cuff muscle with torn tendon are still not clear. Differential scanning calorimetric (DSC) examination is a well-established method for the demonstration of thermal consequences of local and global conformational changes in biological systems. With foregoing studies, authors have demonstrated the feasibility of DSC in the investigation of the musculoskeletal system. The aim of this study was to establish the thermograms of the rotator cuff muscles with normal and torn tendons, experimentally induced in rabbits. The DSC results clearly proved that definitive differences are present between the muscles with normal and torn tendons, which have also been demonstrated by MRI and CT scans.     

Calorimetric investigation of normal and pathological human meniscus

In this study, human meniscus tissue of normal origin in young adults and in patients with early and late stages of osteoarthritic degeneration were analyzed for their thermoanalytical properties with differential scanning calorimetry. Degenerative changes of knee menisci frequently result from trauma to the joint or are associated with joint diseases. Meniscus damage may play an important role in osteoarthritis pathophysiology. The purpose was to further characterize the altered metabolism in matrix composition during different stages of meniscus degeneration that promotes disease progression. The human knee joint menisectomy specimens were received after surgical removal. The calorimetric properties of samples were determined by DSC method, samples were heated from 0 to 80 °C. The heating rate was 0.3 °C min^?1. Conventional Hastelloy batch vessels were used with 40 μL sample volume. Change in the enthalpy was observed in normal cartilage as 1632.48 J g^?1 (SD = 50.55). In case of early degeneration a greater change at 1707.83 J g^?1 (SD = 112.46), while in the severely degenerated samples at 1677.30 J g^?1 (SD = 182.48) was measured. This method proved to be suitable for compositional thermoanalytical study of normal and degenerative human meniscus samples. All samples that were extracted for this study were obtained during live surgeries. With the rise of temperature an endothermic reaction was observed in all cases. The enthalpy change of the process initiated by the temperature change showed difference between the normal and pathological groups.     

Differential scanning calorimetric and histological examinations of the long head of the biceps in cadavers

Shoulder pain is a common presentation of the dysfunction of the glenohumeral joint. The long head of the biceps tendon has been proposed as a source of pain in rotator cuff pathologies. The rotator cuff is a dynamic stabilizer of the glenohumeral joint, and its tear can create different shoulder dysfunctions. The long head of the biceps has a special intraarticular localisation, so the arthricular destruction affects its tendon too. In the process of the rotator cuff degeneration and tear the structure of the biceps tendon pathological transforms. With foregoing studies authors have demonstrated the feasibility of DSC in the investigation of the musculoskeletal system. The aim of this study was to establish the curves and the histological properties of the tendon of the long head of the biceps in different magnitudes of the rotator cuff tear on cadavers. The DSC results clearly proved that definitive differences are present between the structural state of the tendons in different magnitudes of the rotator cuff tears, which have also been demonstrated by the histological examination.     

循证护理模式对关节镜下前交叉韧带重建术患者康复锻炼遵从性的影响

目的探讨了循证护理模式对关节镜下前交叉韧带重建术患者康复锻炼遵从性的影响。方法选取在武汉科技大学附属孝感医院接受治疗的63例关节镜下前交叉韧带重建术患者,随机分为观察组32例,对照组31例,对照组行常规护理,观察组实施循证护理,比较两组护理前后康复锻炼总遵从率。结果护理后对照组总遵从率为77.42%,观察组为100%,组间比较差异具有统计学意义(P0.05)。结论对关节镜下前交叉韧带重建术患者行循证护理,可有效提高患者康复锻炼遵从性。     

A new approach for assessing early osteoarthritis in the rat

Several animal models have been developed to investigate osteoarthritis and potential disease-modifying therapeutics. However, early disease data from these models are limited by the resolution of current imaging modalities. In this in-vitro study, an optical coherence tomography (OCT) system with an axial resolution of 15 µm was used to track sequential changes in osteoarthritic rat knees. Osteoarthritis was induced via transection of the medial collateral ligament and an artificial full thickness meniscal tear. Imaging occurred at one, two, and three weeks after surgery. OCT successfully detected early signs of osteoarthritic change, including alteration of the cartilage surface and disruption of the bone–cartilage interface. This study demonstrates that OCT, along with the induction of mechanical injury, provides an excellent model for monitoring the sequential changes of osteoarthritis.     

Tailored nanoporous gold for ultrahigh fluorescence enhancement

We report molecular fluorescence enhancement of free-standing nanoporous gold in which the nanoporosity can be arbitrarily tailored by the combination of dealloying and electroless gold plating. The nanoporous gold fabricated by this facile method possesses unique porous structures with large gold ligaments and very small pores, and exhibits significant improvements in surface enhanced fluorescence as well as structure rigidity. It demonstrates that the confluence effect of improved quantum yield and excitation of fluorophores is responsible for the large fluorescence enhancement due to the near-field enhancement of nanoporous gold, which arises from the strong electromagnetic coupling between neighboring ligaments and the weakening of plasmon damping of the large ligaments because of the small pore size and large ligament size, respectively.     

Differential scanning calorimetric examination of ruptured lower limb tendons in human

The tendon ruptures are serious injuries of the lover limb in middle age and physically active population. While the Achilles tendon rupture is common, the patellar ligament and quadriceps ligament ruptures are an absolutely rare injury. Usually there is no correlation between the velocity of the trauma and the supervening of the rupture. The aetiology of the degenerative changes in the collagen structures of the tendons and ligaments which could be disposed for the rupture are still not clear. Our hypothesis was that before the injury there are clear pathological abnormalities in the tissues of the tendons, which are predisposed for the rupture, and could be monitored besides the classical histological methods by differential scanning calorimetry. The thermal denaturation of human samples was monitored by a SETARAM Micro DSC-II calorimeter. All the experiments were performed between 0 and 100 °C. The heating rate was 0.3 K/min. DSC scans clearly demonstrated significant differences between the control and ruptured samples (control: T _m = 59.7 °C, T _1/2 = 1.4 °C and ΔH _cal = 8.54 J/g; ruptured Achilles tendon: T _m = 62.75 °C, T _1/2 = 2.6 °C and ΔH _cal = 1.54 J/g, ruptured Quadriceps tendon: T _m = 64.8 °C, T _1/2 = 1.6 °C and ΔH _cal = 1.53 J/g, ruptured Patellar tendon: T _m = 63.9 °C, T _1/2 = 1.41 °C and ΔH _cal = 0.97 J/g). These observations could be explained with the structural alterations caused by the biochemical processes. With our investigations we could demonstrate that DSC is a useful and well applicable method for the investigation of collagen tissue of the degenerated human tendons and ligaments. We can prove with this method that the degenerative changes of the tissue elements increase the thermal stability of collagen tissues of the tendons which could be disposed for the rupture.     

Platinum‐Coated Porous Gold Nanorods in Methanol Electrooxidation: Dependence of Catalytic Activity on Ligament Size

Here we demonstrate that, in the dealloying process of Au–Ag nanorods, temperature is the key parameter for producing porous Au nanorods with tunable ligament sizes. The vertically aligned Au–Ag alloy nanorods were first synthesized by the electrochemical co‐deposition of Au and Ag onto anodic aluminum oxide (AAO) membrane templates. Porous Au nanorods were then obtained by selectively etching Ag away from the precursor Au–Ag alloy nanorods. Control of the ligament size was achieved by controlling the dealloying temperature. Pt deposited on the porous Au nanorods with smaller ligaments exhibited a higher catalytic activity during methanol electrooxidation than those deposited on nanorods with larger ligaments produced by dealloying at higher temperatures. The strong dependence of the catalytic activity on the ligament size of porous Au is principally due to different amounts of carbon monoxide (CO) generated during methanol electrooxidation. Less CO was generated as the ligament size decreased. This finding is of importance for developing highly efficient cathode materials for carrying out methanol electrooxidation in practical applications in which porous Au with a large surface area is used as a supporting substrate.     

DSC analysis of human synovial fluid samples in the diagnostics of non-septic and septic arthritis

The synovial fluid analysis is an important method in diagnosing and managing septic arthritis. To reach a quick diagnosis, preferably faster than the microbiological cultures, could be a great advantage in the therapy. The differential scanning calorimetry (DSC) has recently been found useful in the differential diagnosis of septic and non-septic periprosthetic conditions. The aim of this study was to evaluate whether there is a specific pattern in the different grades of arthritis, and the effect of three different bacterial strains inoculated in synovial fluid. The sensitivity of our method was also determined by using synovial fluid samples with the different bacterial concentrations. Authors developed a standardized, experimental model to assess the denaturation characteristics of non-septic and inoculated synovial fluid, infected by different bacterial strains. The thermal characteristics [maximal denaturation temperature (T _m) and calorimetric enthalpy change (ΔH _cal)] were monitored by SETARAM Micro DSC-II calorimeter. The denaturation scans clearly demonstrated specific, representative curves in the case of different grades of arthritis, as well as with each individual bacterial strain. Therefore, thermoanalyses of human synovial fluid samples by DSC could be a useful tool in the staging of osteoarthritis and the diagnostics of septic arthritis.     

Angiotensin converting enzyme gene polymorphism in Korean patients with primary knee osteoarthritis

Angiotensin converting enzyme (ACE) plays an important role in the physiology of vasculature, blood pressure and inflammation. ACE gene, known to have insertion/deletion (I/D) polymorphism, has been widely investigated in its relation with cardiovascular and neurodegenerative diseases and longevity. ACE gene polymorphism in an inflammation associated osteoarthritis (OA) patients is not known. Here we have investigated ACE gene polymorphism in 142 Korean primary knee OA patients and 135 healthy volunteers to establish any clinical correlates between ACE polymorphism and knee osteoarthritis. Clinical parameters such as disease onset age, Kellgren-Lawrence grade and Lequesne's functional index provided additional analysis of the relationship of ACE polymorphism and clinical features of OA. Early onset OA showed significantly higher allele frequency and carriage rate of I than late onset OA. Radiographically severe and functionally poor OA showed higher carriage rate of I allele than radiographically mild and functionally good OA, respectively. This study first reports ACE gene polymorphism to be a risk factor for early onset, severe form primary knee OA.     

DSC analysis of human fat tissue in alcohol-induced avascular necrosis of the femoral head

Avascular necrosis of human femoral head (ANFH) causes incongruity in the joint that leads to disability in patients requires total hip arthroplasty (THA). Several etiological factors of ANFH have been proposed in the literature but there are cases of idiopathic origin. We observed macroscopic variation in quality of the subcutaneous fat tissue in patients with ANFH compared to patients with osteoarthritis or hip fracture during THA procedures. The samples were analysed by histology, gas chromatography (GC) and differential scanning calorimetry (DSC). Conclusion: the alteration in the fatty acid profile did not cause histological changes, however we could detect biochemical changes using DSC and GC.     

DSC analysis of human fat tissue in idiopathic avascular necrosis of the femoral head

Avascular necrosis of human femoral head (ANFH) causes incongruity in the joint that leads to disability in patients requires total hip arthroplasty (THA). Several etiological factors of ANFH have been proposed in the literature but there are cases of idiopathic origin. We observed macroscopic variation in quality of the subcutaneous fat tissue in patients with ANFH compared to patients with osteoarthritis or hip fracture during THA procedures.The samples were analysed by histology, gas chromatography (GC) and differential scanning calorimetry (DSC).Conclusion: the alteration in the fatty acid profile did not cause histological changes, however we could detect biochemical changes using DSC and GC.     

Determination of the heatsetting temperature of polyester by TMA

The determination of the effective temperature of the thermal treatment applied to polyester substrates in the textile process has been broadly studied by differential scanning calorimetry (DSC). In this investigation, the authors have studied the possibilities of the thermomechanical analysis (TMA) as a method for the determination of this temperature. For this purpose, fabrics of polyester heatset in an industrial plant between 160 and 210°C, have been analyzed by DSC and TMA. The good results obtained show the possibilities of this technique for the determination of the effective temperature of a thermal treatment. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of adenovirus-mediated bFGF, IL-1Ra and IGF-1 gene transfer on human osteoarthritic chondrocytes and osteoarthritis in rabbits

The study investigated the effects of adenovirus-mediated gene transfection of basic fibroblast growth factor (bFGF), bFGF combined with interleukin-1 receptor antagonist protein (IL-Ra) and/or insulin-like growth factor-1 (IGF-1) both in human osteoarthritis (OA) chondrocytes and rabbits OA model. Human OA chondrocytes were delivered by adenovirus-mediated bFGF, IL-Ra and IGF-1 vectors, respectively. Chondrocyte proliferation, glycosaminoglycan (GAG) content, expression of type II collagen, ADAMTS-5, MMP-13, MMP-3 and TIMP-1 were determined. Rabbit OA model was induced by anterior cruciate ligament transaction (ACLT) in knees. Adenoviral vectors encoding human bFGF, IL-Ra and IGF-1 were injected intraarticularly into the knee joints after ACLT. The effects of adenovirus- mediated gene transfection on rabbit OA were evaluated. In vitro, the transfected genes were expressed in cell supernatant of human OA chondrocytes. AdbFGF group significantly promoted chondrocyte proliferation, and increased GAG and type II collagen synthesis than in the OA group. As two or three genes were transfected in different combinations, there was significant enhancement on the GAG content, type II collagen synthesis, and TIMP-1 levels, while ADAMTS-5, MMP-13, and MMP-3 levels were reduced. In vivo, the transfected genes were expressed in synovial fluid of rabbits. Intraarticular delivery of bFGF enhanced the expression of type II collagen in cartilage and decreased cartilage Mankin score compared with the OA control group (P = 0.047; P < 0.01, respectively). Multiple-gene transfection in different combinations showed better results than bFGF transfection alone. This study suggests that bFGF gene transfection is effective in treating experimental OA. Multiple gene transfection has better biologic effects on OA.     

Characterization of Ethylene methyl methacrylate and Ethylene butylacrylate Copolymers with Interactive Liquid Chromatography

Summary: Copolymers of ethylene with methyl methacrylate (EMMA) and butyl acrylate (EBA), which are of different average chemical composition and block lengths according to NMR analysis, were analyzed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC), Crystallization Analysis Fractionation (CRYSTAF), and high performance liquid chromatography at high temperature (HT-HPLC). With CRYSTAF and DSC crystallizing fractions were detected only in some samples. HT-HPLC fractionated all the samples irrespective of their crystallinity. Homopolymers, PMMA and PE were also found in the copolymer samples of EMMA. EMMA and EBA were separated in HPLC according to the content of polar comonomer. A linear correlation between the MMA content and elution volume could not be established due to the presence of homopolymers as admixtures. In such a case the average chemical composition obtained by NMR does not correspond to the real chemical composition of the copolymers. Unlike EMMA the EBA samples eluted in single peaks, which was used for evaluation of their chemical composition distribution. The comparison of results obtained by fractionation via CRYSTAF and HT-HPLC clearly demonstrates the advantages of the chromatographic approach to study the chemical heterogeneity of olefin based copolymers.     

Thermal analysis of the polymerization process on the surface of inorganic fillers

The thermal polymerization of pentabromobenzyl (mono)acrylate (PBB-MA) on the surface of the inorganic fillers Mg(OH)₂ and CaCO₃ was studied. FTIR spectroscopy and extraction of the polymer in bromobenzene show that polypentabromobenzyl acrylate (PBB-PA) was mostly grafted on the surface of Mg(OH)₂. Thermal analysis (TG, DSC, isothermal DSC (IDSC)) demonstrated an increase in polymerization starting temperature, and differences in polymerization enthalpy and apparent activation energy when an inorganic filler is added. These differences depend on the chemical composition of the filler used.The authors acknowledge valuable discussions with Prof. S. Yariv. The authors are also grateful to Berecha Foundation (Geneva) for the financial support of this work.     

On the interaction of the morphological structure and the LC behaviour of LC side group block copolymers

The interaction between morphological structure and phase behaviour of a group of LC side group block copolymers have been investigated using DSC, TEM and small angle X-ray diffraction. Generally, phase separation between the two blocks was observed. It was found that in the case of those samples, where the liquid crystalline sub-phase is not continuous (spheres), only a nematic phase is seen, whereas in all samples in which there is a continuous liquid crystalline sub-phase, the smectic A phase of the homopolymer is formed. On the other hand, the block copolymer seems to stabilise the LC-phase and the polymer properties in general, no dependency of the clearing temperatures and of the glass transition temperatures from the molecular weight of the LC blocks has been detected.