The isolation of glycoproteins from bovine achilles tendon and their interaction with collagen.
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ABSTRACT:
SUBMITTER: Anderson JC
PROVIDER: S-EPMC1178572 | biostudies-other | 1972 Mar
REPOSITORIES: biostudies-other
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Project description:This paper presents a more systematic study of steady-state and time-resolved autofluorescence spectroscopy of collagen isolated from bovine Achilles tendon. In steady-state fluorescence measurements, the excitation and emission spectra of collagen powder, recorded at different fluorescence excitation and detection wavelengths, were compared with the fluorescence excitation and emission spectra of the amino acids phenylalanine, tyrosine, and tryptophan, as well as with similar spectra for 13 autofluorescent collagen cross-links, which have been identified and described in the literature so far. In time-resolved studies, fluorescence was excited by the pulsed light of different wavelengths, and for each excitation wavelength, fluorescence decay was recorded for several detection wavelengths. Data analysis allowed recovery of the fluorescence decay times for each experimental excitation detection event. The obtained information on the decay times of the measured fluorescent signals was discussed, taking into account the available literature data from similar studies of isolated collagen and collagen-rich tissues. Based on the obtained results, it was found that the shape and position of the measured fluorescence excitation and emission spectra of collagen strongly depend on the emission and excitation wavelengths selected in the measurements. From the recorded excitation and emission bands of collagen, it can be concluded with high probability that there are additional, so far unidentified, collagen cross-links, which can be excited at longer excitation wavelengths. In addition, the collagen excitation spectra were measured at longer emission wavelengths at which the collagen cross-links emit fluorescent light. In addition to the emission spectra obtained for excitation in the deep-UV region, the results of time-resolved fluorescence studies with excitation in the deep-UV region and detection at longer wavelengths suggest that fluorescence excitation energy transfer processes occur from the amino acids to the collagen cross-links, and also between the cross-links themselves.
| S-EPMC10145534 | biostudies-literature
Project description:The Achilles tendon exhibits anatomical variations in subtendon twist among individuals, and its compliance can change due to conditions like Achilles tendinopathy. However, current musculoskeletal models overlook these material and morphological variations. This study aimed to investigate the impact of altering Achilles subtendon insertion points and compliance on the triceps surae muscle forces, and therefore tendon loading, during dynamic exercises in one Achilles tendinopathy patient. First, subtendon insertion points were altered in the musculoskeletal model based on a subject-specific 3D freehand ultrasound model and for three types of subtendon twists: low, medium, and high. Second, tendon compliance was modeled based on experimental values, creating three musculoskeletal models: compliant, mean, and stiff. Results indicated that tendon compliance had a larger effect than tendon twist on triceps surae muscle forces. Altering subtendon insertion points to the three types of twist showed a maximal change of 2.3% in muscle force contribution compared to the no-twist model. During the eccentric rehabilitation exercise-a common exercise choice during rehabilitation-the compliant tendon model showed substantial differences compared to the generic (control) musculoskeletal model, resulting in decreased gastrocnemius medialis (-3.5%) and gastrocnemius lateralis (-3.2%) contributions and increased soleus contribution (+ 6.6%). Our study results highlight the necessity of incorporating tendon compliance in musculoskeletal models to accurately predict triceps surae muscle forces, especially in individuals with increased tendon compliance, such as patients with Achilles tendinopathy. Such findings contribute to more accurate predictions of muscle forces and hence, personalized rehabilitation strategies.
| S-EPMC11291231 | biostudies-literature
Project description:In the treatment of acute Achilles tendon rupture, recent studies demonstrate that conservative treatment with functional rehabilitation provides good results, with nearly identical postoperative rerupture rates when compared with surgical treatment. Surgical treatment is indicated in patients with particular conditions, such as patients who are young active athletes who require early return to play or those who wish to avoid the muscle atrophy associated with conservative methods. If surgery is the selected option for treatment, the postoperative complications of each type of surgery must be considered. In conventional open repair, the most common complication is soft-tissue infection due to the high tension of soft tissue affected from the bowstring of the repaired tendon being kept in the equinus position of the ankle. For percutaneous methods, sural nerve entrapment and injury are the most commonly reported complications. Other methods, including endoscopy, require technical expertise as well as special equipment. Several types of combination approaches have been explored in the literature. We describe a combined open and percutaneous technique to repair the Achilles tendon, called the hybrid Achilles tendon repair. This technique has been developed to provide a simplified and reproducible method of hybrid repair in which the complications of previous methods are avoided and which can be done without special equipment.
| S-EPMC6019910 | biostudies-literature
Project description:PURPOSE AND HYPOTHESIS:Adjuvant intermittent pneumatic compression (IPC) during leg immobilization following Achilles tendon rupture (ATR) has been shown to reduce the risk of deep venous thrombosis. The purpose of this study was to investigate whether IPC can also promote tendon healing. METHODS:One hundred and fifty patients with surgical repair of acute ATR were post-operatively leg immobilized and prospectively randomized. Patients were allocated for 2 weeks of either adjuvant IPC treatment (n = 74) or treatment-as-usual (n = 74) in a plaster cast without IPC. The IPC group received 6 h daily bilateral calf IPC applied under an orthosis on the injured side. At 2 weeks post-operatively, tendon healing was assessed using microdialysis followed by enzymatic quantification of tendon callus production, procollagen type I (PINP) and type III (PIIINP) N-terminal propeptide, and total protein content. 14 IPC and 19 cast patients (control group) consented to undergo microdialysis. During weeks 3-6, all subjects were leg-immobilized in an orthosis without IPC. At 3 and 12 months, patient-reported outcome was assessed using reliable questionnaires (ATRS and EQ-5D). At 12 months, functional outcome was measured using the validated heel-rise test. RESULTS:At 2 weeks post-rupture, the IPC-treated patients exhibited 69% higher levels of PINP in the ruptured Achilles tendon (AT) compared to the control group (p = 0.001). Interestingly, the IPC-treated contralateral, intact AT also demonstrated 49% higher concentrations of PINP compared to the non-treated intact AT of the plaster cast group (p = 0.002). There were no adverse events observed associated with IPC. At 3 and 12 months, no significant (n.s.) differences between the two treatments were observed using patient-reported and functional outcome measures. CONCLUSIONS:Adjuvant IPC during limb immobilization in patients with ATR seems to effectively enhance the early healing response by upregulation of collagen type I synthesis, without any adverse effects. Whether prolonged IPC application during the whole immobilization period can also lead to improved long-term clinical healing response should be further investigated. The healing process during leg immobilization in patients with Achilles tendon rupture can be improved through adjuvant IPC therapy, which additionally prevents deep venous thrombosis. LEVEL OF EVIDENCE:Randomized controlled trial, Level I.
| S-EPMC6061441 | biostudies-literature
Project description:PurposeTo evaluate differences of Achilles tendon (AT) hardness and morphology between asymptomatic tendons in patients with acute AT ruptures on the contralateral side and asymptomatic tendons in healthy people by using computer-assisted quantification on axial-strain sonoelastography (ASE).MethodsThe study consisted of 33 asymptomatic tendons in 33 patients (study group) and 34 tendons in 19 healthy volunteers (control group). All the tendons were examined by both ASE and conventional ultrasound. Computer-assisted quantification on ASE was applied to extract hardness variables, including the mean (Hmean), 20th percentile (H20), median (H50) and skewness (Hsk) of the hardness within tendon, and the ratio of the mean hardness within tendon to that outside tendon (Hratio) and three morphological variables: the thickness (THK), cross-sectional area, and eccentricity (ECC) of tendons.ResultsThe Hmean, Hsk, H20, H50, and Hratio in the proximal third of the tendon body in study group were significantly smaller than those in control group (Hmean: 0.43±0.09 vs 0.50±0.07, p=0.001; Hsk: -0.53±0.51 vs -1.09±0.51, p<0.001; H20: 0.31±0.10 vs 0.40±0.10, p=0.001; H50: 0.45±0.10 vs 0.53±0.08, p<0.001; Hratio: 1.01±0.25 vs 1.20±0.23, p=0.003). The THK and cross-sectional area of tendons in the study group were larger than those in the control group (p<0.05).ConclusionsAs a quantitative objective method, the computer-assisted ASE reveals that the asymptomatic ATs contralateral to acute rupture are softer than those of healthy control group at the proximal third and the asymptomatic tendons in people with rupture history are thicker, larger, and rounder than those of normal volunteers especially at the middle and distal thirds of AT body.
| S-EPMC6304598 | biostudies-literature
Project description:BACKGROUND:Spontaneous Achilles tendon rupture associated with long-term dexamethasone (Dex) use has been reported. However, few studies have investigated the potential mechanism. The aim of this study was to evaluate the effects of oral Dex on type I collagen in humans and rats and its association with tendon rupture. METHODS:First, six Achilles tendons from patients who received long-term Dex treatment, and another six normal tendons were harvested for histological evaluation. Secondly, 8-week-old rats (n?=?72) were randomly assigned to a Dex group or a control group. Type I collagen was studied at the mechanical, histological, and molecular levels after 3 and 5?weeks. Tenocytes isolated from normal human and rat tendon were used to investigate the effect of Dex on cellular scale. RESULTS:Histological analysis of human and rat tendon tissue revealed an irregular, disordered arrangement of type I collagen in the Dex group compared with the control group. In addition, In the Dex+ group, type I collagen expression decreased in comparison with the Dex- group in both human and rat tenocytes. The mechanical strength of tendons was significantly reduced in the Dex group (68.87?±?11.07?N) in comparison with the control group (81.46?±?7.62?N, P?=?0.013) after 5?weeks. Tendons in the Dex group were shorter with smaller cross-sectional areas (10.71?±?0.34?mm2, 1.44?±?0.22?mm2, respectively) after 5?weeks than those in the control group (11.13?±?0.50?mm2, P?=?0.050, 2.74?±?0.34?mm2, P?<?0.001, respectively). CONCLUSIONS:This finding suggests long-term use of Dex that decreases the expression of type I collagen at molecular and tissue levels both in human and rat Achilles tendons. Furthermore, Dex decreases the mechanical strength of the tendon, thereby increasing the risk of Achilles tendon rupture.
| S-EPMC7038574 | biostudies-literature
Project description:Achilles tendon injuries have been on the rise secondary to our increased participation in sports, increase in societal obesity rates, and the growing elderly population. There has been disagreement in recent years about whether to treat injuries such as Achilles tendon ruptures operatively or nonoperatively with aggressive functional rehabilitation. For those opting to surgically manage Achilles tendon ruptures, insertional Achilles tendonitis, or augment the described SpeedBridge Achilles tendon repair, we propose a modified rip-stop technique. The goal of this technique is to provide a biomechanical advantage to our current operative interventions for these injuries, a greater load-to-failure and a speedier, more reliable return to sport in our athletic populations.
| S-EPMC8417224 | biostudies-literature
Project description:Superior capsular reconstruction (SCR) has become an increasingly popular choice in the treatment of massive, irreparable rotator cuff tears, pseudoparalysis, and in cases in which revision of previous rotator cuff repair is indicated. The SCR procedure is intended to restore the superior stabilizing forces of a deficient rotator cuff. This technique is accomplished by substituting an autograft or allograft between the superior glenoid and the greater tuberosity of the humerus, thus keeping the humeral head centered in the glenoid during shoulder forward flexion and abduction. Since its advent, numerous techniques have been described for this procedure. A fascia lata autograft was initially described; however, many surgeons in the United States have advocated for the use of a humeral dermal allograft. Yet, biomechanical studies have demonstrated elongation and thinning of this material. Thus, the Achilles tendon allograft may be an attractive choice for SCR, given its previous success with ligamentous and tendinous reconstructions. In this article, we present our technique of SCR using an Achilles tendon allograft.
| S-EPMC7189387 | biostudies-literature
Project description:Revision quadriceps tendon repair presents a challenging problem for the treating surgeon because of associated anatomic defects such as large tendon-gap deficits and preexistent poor tissue quality. Current methods for revision quadriceps tendon repair use tendon autograft, which may predispose to additional morbidity because the repair relies only on soft tissue fixation. In this Technical Note, we describe a technique for revision of a failed quadriceps tendon repair with a large tendon gap using a trapezoidal plug Achilles tendon allograft. This technique constitutes a safe and effective approach to revising failed primary quadriceps tendon repairs, is suitable for large-gap defects, and has the ability to withstand large force transmissions.
| S-EPMC6848963 | biostudies-literature
Project description:BackgroundInfection following Achilles tendon surgery is a devastating complication and can be difficult to treat and often leads to poor outcomes. A number of treatments have been described, but there is little information concerning outcomes of these treatments. Our purpose was to evaluate the clinical and functional outcomes of patients who have undergone treatment for an infected Achilles tendon after acute and chronic midsubstance repair.MethodsWe retrospectively reviewed the medical records of 20 patients who had undergone surgical treatment for an infected Achilles tendon between 2000 and 2016. The mean follow-up time was 21 months (range, 2-68 months). All patients underwent extensive debridement of the tendon with removal of all infected tissue and foreign material. Soft tissue wound coverage was utilized for large wounds that were not amenable to primary or secondary closure. All patients received culture-specific intravenous (IV) antibiotics for 3 to 6 weeks. Postoperatively, the extremity was immobilized in a splint followed by a cast until the wound was healed. The cast was then replaced with a walking boot and the patients were provided a physical therapy program. Functional outcomes were measured using the Foot and Ankle Ability Measure (FAAM) Activity of Daily Living (ADL) scale.ResultsAll wounds had healed at the time of last follow-up. Three patients (15%) required an unplanned return to the operating room for repeat debridement. All patients were able to walk without the use of a gait aid. Five patients (25%) required continued use of a boot or brace during ambulation. Fourteen patients participated in the FAAM ADL survey. There were 6 patients lost to follow-up. The average FAAM score was 87 (range, 71.4-100). At last follow-up, most patients reported their overall function as "normal" or "nearly normal." Eradication of infection and satisfactory functional results can be attained after radical debridement, wound closure, and administration of culture-specific IV antibiotics.Level of evidenceLevel IV, retrospective case series.
| S-EPMC8696926 | biostudies-literature