Ligament Fibers Research Articles

Raloxifene administration enhances retention in an orthodontic relapse model.

Orthodontic relapse is a physiologic process that involves remodelling of the alveolar bone and principle periodontal ligament fibres. Raloxifene is an Food and Drug Administration (FDA)-approved selective oestrogen receptor modulator that inhibits systemic bone loss. In our study, we examined the effects of Raloxifene on alveolar bone modelling and orthodontic relapse in a rodent model. The efficacy of raloxifene was evaluated in 15-week-old male Wistar rats, 8 in each group (Control, Raloxifene, Raloxifene + 7-day relapse, Raloxifene + 14-day relapse) for a total of 42 days. All animals had 14 days of orthodontic tooth movement with a closed nickel-titanium coil spring tied from incisors to right first molar applying 5-8 gm of force. On the day of appliance removal, impression was taken with silicon material and the distance between first molar and second molar was filled with light-cured adhesive resin cement for retention phase. Raloxifene Retention, Raloxifene Retention + 7D, Raloxifene Retention + 14D groups received 14 daily doses of raloxifene (2.0 mg/kg/day) subcutaneously after orthodontic tooth movement during retention. After 14 days of retention, the retainer was removed and right first molar was allowed to relapse for a period of 14 days. Raloxifene injection continued for the Raloxifene + 14-day relapse group during relapse phase too. Control group received saline injections during retention. Animals were euthanized by CO2 inhalation. The outcome measure included percentage of relapse, bone volume fraction, tissue density, and histology analysis using tartrate-resistant acid phosphatase staining and determining receptor activator of nuclear factor-кB-ligand (RANKL) and osteoprotegerin expression. Raloxifene Retention + 14D group had significantly less (P < 0.05) orthodontic relapse when compared with other groups. There was a significant increase (P < 0.05) in bone volume fraction and tissue density in the Raloxifene Retention + 14D group when compared with other groups. Similarly, there was significant decrease in number of osteoclasts and RANKL expression in Raloxifene Retention + 14D group when compared with Raloxifene Retention + 7D group (P < 0.05). Raloxifene could decrease post-orthodontic treatment relapse by decreasing bone resorption and indirectly enhancing bone formation.

A biomechanical study after combined reconstruction of the anterior cruciate and anterolateral ligaments: Comparison between anatomic anterolateral ligament reconstruction and lateral tenodesis using the modified Lemaire technique

Objectives:To determine the stabilizing role of the anterolateral ligament reconstruction (ALLR) and the modified Lemaire lateral extraarticular tenodesis (LET) performed in combination with anterior cruciate ligament reconstruction (ACLR) and to determine if one of these two procedures was superior to the other.Methods:Six non paired cadaveric knees were tested with a 6 degrees of freedom robotic system (KUKA Robotics). Internal rotation and anterior tibial translation were measured between 0 and 90° knee flexion after applying 5 N-m Torque and a 134-N anterior load, respectively. A full kinematics assessment was performed in each following conditions: intact knee, after section of the anterior cruciate ligament (ACL), after section of the ACL and anterolateral ligament (ALL) and Kaplan fibers, after isolated ACLR, after combined ACLR+LET and ACLR+ALLR. ALLR was performed using Gracilis tendon while central strip of the ilio-tibial band was used for the modified Lemaire procedure.These different states were compared using a Tukey paired comparison test.Results:In combined ACL and anterolateral deficient knee, anterior translation and internal rotation remained significantly increased after isolated ACLR compared to intact knee (+2.33 ± 1.44 mm and +1.98 ± 1.06°; p > 0.01). On the other hand, the addition of an ALLR or a modified Lemaire LET to the ACLR allowed to restore anterior translation and internal rotation to values similar to the intact knee. Finally, the two anterolateral procedures had not significantly different values in both tests. This difference was 0.67 ± 1.46 mm for anterior translation (p=0.79) and 0.11 ± 1.11° for internal rotation (p=0.99).Conclusion:In ACL and anterolateral deficient knee, combined ACLR and anterolateral reconstruction allowed restoration of native stability of the knee in anterior translation and internal rotation contrary to isolated ACLR.Additionally, both types of extra-articular reconstruction, ALLR or modified Lemaire procedure, were similar in terms of restoring knee kinematics and neither overconstrained the knee.

A biomechanical comparison of the main anterolateral procedures used in combination with anterior cruciate ligament reconstruction

Background:None of the anterolateral procedures used in combination with ACL reconstruction (ACLR) to control rotational laxity have demonstrated superiority. The objective was to compare the capacity of the main anterolateral procedures associated with ACLR to restore intact knee kinematics in case of combined ACL and anterolateral structure injury.Methods:The complete kinematics of 10 cadaveric knees, previously modelled by TDM, were recorded using a 3D Motion Analysis® system. Intact knee kinematics, including internal rotation (IR) of the tibial and anterior-posterior (AP) laxity at 30 and 90° flexion were initially assessed, followed by a sequential section of the ACL and anterolateral complex (ALC) (anterolateral ligament (ALL), ALL capsule and Kaplan fibers). After the ACLR, 5 anterolateral procedures were performed consecutively on the same knee: ALLR; Ellison; Deep Lemaire; Superficial Lemaire; and MacIntosh. The last three procedures were randomized. For each procedure, the graft was fixed in neutral rotation at 30° flexion with a tension of 20 N.Results:ACLR alone did not restore overall knee kinematics when there was an ACL+ALC injury, and resulted in residual rotational laxity of the tibia (p > 0.001). Only the ALLR (p=0.262) and modified Ellison (p=0.081) procedures restored normal global IR kinematics. Superficial/deep Lemaire and MacIntosh procedures resulted in over-constrained kinematic profiles (respectively: p=0.013, p=0.018 and p=0.030). In terms of ACLR, the addition of an anterolateral procedure did not provide additional control over AP translation at 30 and 90° (p > 0.05), exception for the surficial Lemaire procedure at 90° (p = 0.032).Discussion:ACLR alone was not sufficient to restore normal kinematics in ACL and ALC-deficient knees. ALLR and Ellison procedures restored physiological kinematics, unlike the MacIntosh procedure which caused additional control of IR and thereby induced over-constraint.Conclusion:The addition of ALLR or the modified Ellison procedure, which restore intrinsic kinematics, might be useful during primary ACL reconstruction to avoid repeated injury without a risk of over-constraint. The superficial/deep Lemaire and MacIntosh procedures resulted in over-constrained kinetics but provided additional rotation control that could be useful in revision surgery.

The strain distribution in the lumbar anterior longitudinal ligament is affected by the loading condition and bony features: An in vitro full-field analysis.

The role of the ligaments is fundamental in determining the spine biomechanics in physiological and pathological conditions. The anterior longitudinal ligament (ALL) is fundamental in constraining motions especially in the sagittal plane. The ALL also confines the intervertebral discs, preventing herniation. The specific contribution of the ALL has indirectly been investigated in the past as a part of whole spine segments where the structural flexibility was measured. The mechanical properties of isolated ALL have been measured as well. The strain distribution in the ALL has never been measured under pseudo-physiological conditions, as part of multi-vertebra spine segments. This would help elucidate the biomechanical function of the ALL. The aim of this study was to investigate in depth the biomechanical function of the ALL in front of the lumbar vertebrae and of the intervertebral disc. Five lumbar cadaveric spine specimens were subjected to different loading scenarios (flexion-extension, lateral bending, axial torsion) using a state-of-the-art spine tester. The full-field strain distribution on the anterior surface was measured using digital image correlation (DIC) adapted and validated for application to spine segments. The measured strain maps were highly inhomogeneous: the ALL was generally more strained in front of the discs than in front of the vertebrae, with some locally higher strains both imputable to ligament fibers and related to local bony defects. The strain distributions were significantly different among the loading configurations, but also between opposite directions of loading (flexion vs. extension, right vs. left lateral bending, clockwise vs. counterclockwise torsion). This study allowed for the first time to assess the biomechanical behaviour of the anterior longitudinal ligament for the different loading of the spine. We were able to identify both the average trends, and the local effects related to osteophytes, a key feature indicative of spine degeneration.

Natural gradient composite made of aragonite nanofibers: the ligament of bivalve Acesta marissinica.

Here we investigate the nanostructure of the fibrous ligament (FL) in bivalve Acesta marissinica, using scanning electron microscopy (SEM) and an image processing method. We find this FL is mirror symmetrical in its transverse section and consists of aragonite nanofibers and organic materials, the former of which are generally arranged in a featherlike pattern along the mirror plane. Further, we find this FL has a unique graded architecture. From its inner (near the mirror plane) to lateral part (near the ligament–shell junction), the nanofiber angle gradually increases from about 20° to 45°, the nanofiber volume fraction remarkably decreases from 70% to 14%, and the nanofiber diameter also changes from about 137 nm to 85 nm. This novel design allows this FL to be both resilient and strong to meet the biofunctional requirements. We expect the present findings may help us to develop new functionally graded materials (FGMs) and further understand bivalve life processes.

Laparoscopic liver resection of the spiegel lobe by a lef-sidad approach preserving an accessory left hepatic artery

Presenter: Víctor Molina | Hospital de la Santa Creu i Sant Pau Background: Caudate lobe of the liver can be divided in three portions: Spiegel lobe, para-caval portion and caudate process . The anatomy of the caudate lobe and its proximity to major vascular structures makes this operation a difficult resection, especially for laparoscopic liver surgery. For that reason the Iwate criteria proposed to classify this surgery at the “2nd International Consensus Conference on Laparoscopic Liver Resection” as intermediate or advanced difficulty depending on the type of resection, and the size of the tumor . For tumors located in the Spiegel lobe, the left side approach is preferred Methods: We present a 69-year-old woman with liver metastasis from previously resected sternal condrosarcoma. A Spiegel lobe resection with left side approach preserving an accessory left hepatic artery was performed. Results: The patient was positioned in supine position. Six ports were used, 4 of 12mm and 2 of 5mm. We started the surgery with the left lateral segment mobilization. The gastrohepatic ligament was opened to expose the caudate lobe. In this case we only opened part of the ligament to preserve the accessory left hepatic artery. We continued retracting to the right the hepatic hilium with tissue band used as the external Pringle tourniquet to expose de caudate process and the right side of the Spiegel lobe. The transection of the liver was started with Thunderbeat and ultrasonic dissector. The portal branches to the Spiegel lobe were dissected and controlled with clips. We continued with the blunt dissection of the Spiegel lobe from the inferior vena cava. The fibrous ligament of the Spigel lobe to the crus of the diaphragm was cut and the retrocaudate vessels to the inferior vena cava were individualized and ligated with clips. Finally, we opened the gastrohepatic ligament behind the artery, pulled up the caudate lobe, and finished the liver transection. A closed aspirative drainage was left in place. The specimen was removed from an enlargement of the left subcostal 12mm port. The operative time was 180 min and the total Pringle time was 30 min. Patient was discharged at the 4 postoperative day and there were no postoperative complications. Conclusion: Laparoscopic liver resection of the caudate lobe for condrosarcoma liver metastasis is feasible and safe. Left approach seems the best option for Spiegel lobe resections even in patients with accessory left hepatic artery.

Dissection in the Pyramidal Space for Effective Relief of Tension in Cleft Palate Repair.

Although several methods of note have been reported for the repair of cleft palate, wound separation and oronasal fistula can still occur. This study reports a useful technique of dissection in the pyramidal space for adequate release of tension and the prevention of palatal fistula. A total of 404 consecutive patients with cleft palate with or without cleft lip who had received standard surgical repair were evaluated. The mucoperiosteal flaps were raised from the hard palate. Dissection was performed in the pyramidal space to expose the greater palatine foramen, neurovascular pedicle, pyramidal process of the palatine bone, opening to the space of Ernst, and hamulus with tensor veli palatini aponeurosis. The restricting ligamentous fibers lateral and posterior to the pedicle were released. The hamulus process was divided at its root and pushed medially for further relief and medial mobilization of the flap. Closure of the flaps was achieved with minimal tension in the midline. The patients received regular postoperative follow-ups. Only 1 case was found to have postoperative palatal fistula, resulting in a fistula rate of 0.25% during the 11-year study period. Adequate dissection in the pyramidal space helped to close the palatal flaps with minimal tension and prevent the formation of palatal fistula.

EFFECT OF DEXAMETHASONE INFILTRATION ON PERIODONTAL LIGAMENT AFTER EXPERIMENTAL MOLAR LUXATION IN RATS

Aim of the study: Dexamethasone is a popular corticosteroid in dental practice. Submucosal infiltration of dexamethasone proved to be effective to relief post-operative symptoms in different clinical and research application. This study was conducted to evaluate the effect of submucosal dexamethasone single injection on the healing of injured periodontal ligament fibers after molar luxation in rats via histological and gene expression studies. Materials and methods:24 Wistar rats were selected for the study. Luxation injuries were performed for all first mandibular molars of both mandibular sides, right & left. Immediately after luxation, the right sides of the mandibles received submucosal injections of dexamethasone sodium phosphate (0.4mg/ml), while left sides were not dexamethasone injected. Follow up periods were 1, 3 & 7 days. Mandibular specimens were studied by routine histology, and quantitative gene expression analysis was done for fibroblast growth factor (FGF2), caspase-3 & alkaline phosphatase (ALP).Results: Histological features revealed superior results of the dexamethasone group with better regeneration and organization of fibers. Gene expression results revealed significant increase in the expression of both FGF2 and alkaline phosphatase (ALP) and a significant decrease in the expression of caspase-3 in the study side when compared to the control side.Conclusion: histologically dexamethasone enhanced the regeneration of torn periodontal ligament fibers with noticeable reduction in inflammation and rise in cellular proliferation. Gene expression reflected the possible benefit of dexamethasone single local injection in the management of periodontal ligament injuries.

Reconstruction of the deep fibers of the distal radioulnar ligaments facilitating atendon graft-Adams' procedure

Anatomical reconstruction of the deep fibers of the distal radioulnar ligaments to stabilise the distal radioulnar joint. Multidirectional instability of the distal radioulnar joint without the possibility for anatomic refixation of the distal radioulnar ligaments. General operative contraindications, infection, insufficient soft tissue coverage, osteoarthritis of the distal radioulnar joint, excessive ulna impaction syndrome, osseous deformation. Dorsal approach to the distal radioulnar joint, preparation of the ulna head, transosseous transfer of tendon graft through the distal ulnar corner of the radius at the sigmoid notch, transfer through the ulnar fovea and transosseous fixation within the ulna head using aninterference screw. Long arm cast for 4-6weeks, then Bowers splint for further 4weeks; optional long arm orthosis without limiting elbow flexion and extension for 4-6weeks, then Bowers splint for further 4weeks; starting exercises after 12weeks. Reconstruction of the distal radioulnar ligaments using tendon grafts stabilises the distal radioulnar joint with restoration of joint kinematics.

Double-Row Fixation for Avulsion of Anterior Cruciate Ligament

Avulsion fractures of the tibial spine (also called “tibial eminence fractures” or “ACL avulsion fractures”), leading to discontinuity of anterior cruciate ligament (ACL) fibers, have been well described in the literature in both the pediatric and adult populations. To ensure the stability of the knee joint and good range of motion with minimal to no laxity, surgical reduction of the fracture and fixation are necessary to restore ACL length. Several arthroscopic techniques have been described to reduce and fix these fractures. We describe a technique using 2 anchors to fix the fractured tibial spine with no need to make any tibial tunnels or any extra leg wounds for the sutures.

Laparoscopic treatment of median arcuate ligament syndrome: a systematic review.

Median arcuate ligament syndrome (MALS) is an uncommon condition caused by the extrinsic compression of the celiac trunk (CT) and celiac ganglion, secondary to an anatomical abnormality of the median arcuate ligament fibers. It is characterized by postprandial epigastric pain, chronic abdominal pain, weight loss, nausea and vomiting. MALS is typically diagnosed after the exclusion of other, more common conditions; however, a variety of imaging and diagnostic modalities, including Duplex ultrasonography, computed tomography angiography, magnetic resonance angiography, gastric tonometry and angiography can suggest findings consistent with MALS. Laparoscopic approach has been proposed as the option of choice for the treatment of these patients. A systematic review of the international literature regarding this modality of treatment is presented here. The review included 504 cases, and several principles are suggested to improve the management. The advantages of this minimally invasive technique include short operative time (136.0 minutes, range 70-242), shorter hospital stay (3.8 days, range 0.5-7) and low rate of conversion to open surgery (4.2%). Various treatment modalities are available to decompress the celiac trunk. Although open surgery has been traditionally accepted as the gold standard, laparoscopic division of the MALS has proven equal results. Others have described different treatment modalities, including bypass surgery and endovascular procedures (angioplasty or stent placement). Laparoscopic approaches to correct MALS are feasible and safe. It may be the preferred modality of treatment in view of its lack of morbidity, shorter hospital stay and good results.

APPLYING POLYGENIC RISK SCORING FOR PSYCHIATRIC AND METABOLIC TRAITS FOR THE PREDICTION OF MAJOR DEPRESSIVE DISORDER AND ITS SUBTYPES IN THE COLAUS|PSYCOLAUS POPULATION-BASED COHORT STUDY

To evaluate mid- and long-term outcomes after arthroscopically-assisted transosseous reattachment of the triangular fibrocartilage complex (TFCC) and to analyze the association of distal radioulnar joint (DRUJ) stability with the clinical outcome.Patients treated with an arthroscopically-assisted transosseous reattachment of the deep layer of the TFCC between 2000 and 2009 and a minimum follow-up of 12 months at mid-term and 4 years at long-term follow-up were retrospectively reviewed. Mayo Modified Wrist Score (MMWS); Disabilities of the Arm, Shoulder and Hand (DASH) score; pain visual analogue scale (VAS); grip strength and stability of the DRUJ were assessed at 2 follow-up clinical examinations. At the last follow-up, the Patient-Rated Wrist Evaluation score was additionally recorded.Thirty patients with a mean age of 29 (±13) years were included. Most of the patients were female (70%, n = 21). The mid-term evaluation took place at a median of 30 months (range, 12-83 months). The assessed scores showed statistically significant clinical improvement (MMWS, P < .001; DASH score P < .001; VAS P < .001). Stability assessment showed a stable DRUJ in 23 (76.7%) patients. At a median of 106 months (range 52-215 months), the long-term clinical assessment was performed. The evaluated scores demonstrated persisting significant improvement (MMWS P < .001; DASH score P < .001; VAS P < .001). Stability assessment showed a stable DRUJ in 19 patients (63.3%). DRUJ instability did not correlate with clinical outcome. No permanent surgery-related complications occurred.Arthroscopically-assisted transosseous reattachment of the deep fibers of radioulnar ligaments leads to excellent and good clinical results in mid- and long-term follow-up. In 95.5% of the analyzed patients, the measured improvement in the DASH score exceeded the in literature reported minimal clinically important difference of 13.5. Loss of DRUJ stability during follow-up was not associated with deterioration of clinical parameters and patient satisfaction.Level IV, retrospective case series.

Periodontal regenerative medicine using mesenchymal stem cells and biomaterials: A systematic review of pre-clinical studies.

The aim of the systematic review was to analyze the use of mesenchymal stem cells (MSC) and biomaterial for periodontal regeneration from preclinical animal models and human. Electronic databases were searched and additional hand-search in leading journals was performed. The research strategy was achieved according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The including criteria were as follows: MSC, biomaterial, in vivo studies, with histologic and radiologic analysis and written in English. The risk of bias was assessed for individual studies. A total of 50 articles were selected and investigated in the systematic review. These results indicate that MSC and scaffold provide beneficial effects on periodontal regeneration, with no adverse effects of such interventions. Future studies need to identify the suitable association of MSC and biomaterial and to characterize the type of new cementum and the organization of the periodontal ligament fiber regeneration.

AVALIAÇÃO CLÍNICA E RADIOGRÁFICA DE INTRUSÃO DENTÁRIA NA DENTIÇÃO DECÍDUA: RELATO DE CASO

Introdução: Os traumatismos dentários são mais comuns na dentição decídua, resultando no deslocamento dentário, os dentes mais afetados, são os incisivos centrais superiores, sendo a luxação intrusiva a mais comum. Objetivo: abordar a ocorrência de um traumatismo dentário do tipo intrusivo, na dentição decídua, descrevendo aspectos relacionados ao diagnóstico, tratamento e proservação da unidade dentária. Relato de caso: Paciente, quatro anos de idade, gênero feminino, apresentou traumatismo dentário condizente com o diagnóstico de luxação intrusiva, foi estabelecido um tratamento conservador, preservando o elemento dentário no arco até que ocorresse a esfoliação do mesmo. No presente caso, obteve-se um bom prognóstico, visto que foi percebida a reerupção do elemento dentário no período de dois meses. Conclusões: O conhecimento das técnicas de manipulação dos traumatismos dento-alveolares e dos tecidos moles é imprescindível para a realização de um tratamento adequado dessas condições. Desta maneira, é importante o cirurgião-dentista ter habilidades no manejo da criança para um correto diagnóstico, estabelecendo um adequado tratamento, para melhor prognostico da unidade dentária.

Periodontal healing by periodontal ligament fiber with or without cells: A preclinical study of the decellularized periodontal ligament in a tooth replantation model.

The periodontal ligament (PDL) comprises cells embedded in the extracellular matrix (ECM) and is required for periodontal healing upon tooth transplantation. However, the extent to which the ECM contributes to periodontal regeneration remains unknown. This study aimed to evaluate effects of separate PDL matrix without cells on periodontal healing. Mandibular premolars extracted from six beagle dogs, were 1) left untreated, 2) decellularized, or 3) surface planed. Cytologic, histologic, scanning electron microscopy, and transmission electron microscopy analyses confirmed that detergents could be used to decellularize the PDL. An additional circumferential osteotomy was performed to replant dental roots into extraction sockets. Radiography and histology were used to evaluate periodontal regeneration 8weeks later, with the data adjusted for multiple testing. In pristine extraction sites, total root resorption (P=0.034), recovered PDL space (P=0.012), and new cementum (P=0.004) were greater in untreated teeth than in roots that underwent surface planing. There were no significant changes when comparing untreated teeth with teeth having a decellularized PDL (P=0.081, P=0.170, and P=1.000, respectively), and decellularized teeth showed significant increase of new cementum compared to surface planed teeth (P=0.048). In the defect area, only the recovered PDL space (P=0.034) was greater in untreated teeth when comparing with denuded roots. These results suggest that in addition to untreated PDL, decellularized PDL also partially supports reattachment (particularly cementogenesis) in pristine extraction sites but not in defect areas.

Injectable Tissue Replacement and Regeneration: Anatomic Fat Grafting to Restore Decayed Facial Tissues.

Summary:Aging is a dynamic process that can be modeled and understood tissue by tissue and cell by cell. Numerous authors have helped us understand the anatomy of facial fat compartments and the effects of aging on our facial tissues such as skin, fat, bone and fibrous ligaments. Injectable tissue replacement and regeneration (ITR2) is a method to replace decayed tissues of the face using “like tissues” in an effort to delay or slow the rate of tissue decay seen in facial aging. Facial topography and proportion analysis are performed to diagnose individual-specific losses of facial fat. The degree of sun damage and skin thinning is noted as is the degree of loss in the superficial fat compartment. Deep compartment fat loss is evaluated as is pyriform aperture, orbital, mandibular ramus, mandibular body, and chin resorption. From this analysis, a detailed treatment plan is formulated. Using a mechanical device, 3 different fat grafts are created: 2 mm (millifat), 1 mm (microfat), and 500 microns (cell optimized, matrix rich nanofat); anatomic replacement of all areas of tissue loss is carried out. Millifat is used for deep compartment and bone losses, microfat for superficial fat losses above the facial musculature and nanofat is used intradermally and as a biological cream for topical application. The rationale behind this standardized approach is explained and the scientific foundations for the idea are presented. Reduction in tissue decay appears to be a valid observation, but awaits others confirmation.

Contributions of elastic fibers, collagen, and extracellular matrix to the multiaxial mechanics of ligament

Elastin is a biopolymer known to provide resilience to extensible biologic tissues through elastic recoil of its highly crosslinked molecular network. Recent studies have demonstrated that elastic fibers in ligament provide significant resistance to tensile and especially shear stress. We hypothesized that the biomechanics of elastic fibers in ligament could be described as transversely isotropic with both fiber and matrix components in a multi-material mixture. Similarly, we hypothesized that material coefficients derived using the experimental tensile response could be used to predict the experimental shear response. Experimental data for uniaxial and transverse tensile testing of control tissues, and those enzymatically digested to disrupt elastin, were used as inputs to a material coefficient optimization algorithm. An additive decomposition of the strain energy was used to model the total stress as the sum of contributions from collagen fibers, elastic fibers, elastic matrix, and ground substance matrix. Matrices were modeled as isotropic Veronda-Westmann hyperelastic materials, whereas fiber families were modeled as piecewise exponential-linear hyperelastic materials. Optimizations provided excellent fits to the tensile experimental data for each treatment case and material model. Given the disparity in magnitude of stresses between longitudinal and transverse/shear tests and agreement between models and experiments, the hypothesized transversely isotropic material of elastin symmetry was supported. In addition, the coefficients derived from uniaxial and transverse tensile experiments provided reasonable predictions of the experimental behavior during shear deformation. The magnitudes of coefficients representing stress, nonlinearity, and stiffness supported the experimental evidence that elastic fibers dominate the low strain tensile and shear response of ligament. These findings demonstrate that the additive decomposition modeling strategy can represent each discrete fiber and matrix constituent and their relative contribution to the material response of the tissue. These experimental data and the validated constitutive model provide essential inputs and a framework to refine existing computational models of ligament and tendon mechanics by explicitly representing the mechanical contributions of elastic fibers.

Modulatory effect of curcumin analogs on the activation of metalloproteinases in human periodontal stem cells.

Periodontitis progresses due to increased levels of active metalloproteinases (MMPs) and the imbalance between MMPs and their tissue inhibitors (TIMPs). Natural curcumin limits the lytic activity of MMPs but has low cellular uptake. Use of synthetic curcumin analogs could be a means of overcoming this limitation of treatment efficiency. Human periodontal stem cells were isolated from gingival tissue, gingival ligament fibers, periodontal ligament, and alveolar bone. The effect of five synthetic curcumin analogs was compared with that of natural curcumin by assessing cytotoxicity [by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay], the cellular uptake (by fluorometry), the proteolytic activities of MMP-2 and -9 (by zymography), and the levels of TIMP-1 (by ELISA). Our results indicated increased cytotoxicity of synthetic curcumins for doses between 100 and 250μM. At a concentration of 10μM, cellular uptake of synthetic curcumins varied depending on their chemical structure. The curcumin compounds modulated pro-MMP-2 levels and increased TIMP-1 production. There was no detectable synthesis of pro-MMP-9 and no activation of MMPs 2 and 9. Gingival tissue and gingival ligament fiber stem cells were most responsive to treatment, showing inverse correlations between pro-MMP-2 and TIMP-1 levels. In conclusion, synthetic curcumins influenced the balance between pro-MMP-2 and TIMP-1 in human periodontal stem cells in vitro, and this could open perspectives for their application as adjuvants in periodontal therapy.

The medial wall of the cavernous sinus. Part 1: Surgical anatomy, ligaments, and surgical technique for its mobilization and/or resection.

The medial wall of the cavernous sinus (CS) is often invaded by pituitary adenomas. Surgical mobilization and/or removal of the medial wall remains a challenge. Endoscopic endonasal dissection was performed in 20 human cadaver heads. The configuration of the medial wall, its relationship to the internal carotid artery (ICA), and the ligamentous connections in between them were investigated in 40 CSs. The medial wall of the CS was confirmed to be an intact single layer of dura that is distinct from the capsule of the pituitary gland and the periosteal layer that forms the anterior wall of the CS. In 32.5% of hemispheres, the medial wall was indented by and/or well adhered to the cavernous ICA. The authors identified multiple ligamentous fibers that anchored the medial wall to other walls of the CS and/or to specific ICA segments. These parasellar ligaments were classified into 4 groups: 1) caroticoclinoid ligament, spanning from the medial wall and the middle clinoid toward the clinoid ICA segment and anterior clinoid process; 2) superior parasellar ligament, connecting the medial wall to the horizontal cavernous ICA and/or lateral wall of the CS; 3) inferior parasellar ligament, bridging the medial wall to the anterior wall of the CS or anterior surface of the short vertical segment of the cavernous ICA; and 4) posterior parasellar ligament, which anchors the medial wall to the short vertical segment of the cavernous ICA and/or the posterior carotid sulcus. The caroticoclinoid ligament and inferior parasellar ligament were present in most CSs (97.7% and 95%, respectively), while the superior and posterior parasellar ligaments were identified in approximately half of the CSs (57.5% and 45%, respectively). The caroticoclinoid ligament was the strongest and largest ligament, and it was typically assembled as a group of ligaments with a fan-like arrangement. The inferior parasellar ligament was the first to be encountered after opening the anterior wall of the CS during an interdural transcavernous approach. The authors introduce a classification of the parasellar ligaments and their role in anchoring the medial wall of the CS. These ligaments should be identified and transected to safely mobilize the medial wall away from the cavernous ICA during a transcavernous approach and for safe and complete resection of adenomas that selectively invade the medial wall.

Morphological changes of annular ligament at stenosing ligamentitis of the fingers of the hand.

Background. According to the data of the world literature among the diseases of the tendon-ligament apparatus of the hand, the processes of stenosis of the fibrous channels amount to 43.8%, and the stenosing ligamentitis of the fingers of the hand - up to 22.3% of cases. The pathogenesis of the disease is not fully established. Objective . To complete knowledge of the pathogenesis of stenosingligamentitis of the fingers of the hand through histological and morphometric studies. The study material was biopsy specimens of the altered ring-shaped ligament in 57 adult patients received during surgery. For a comparative assessment of morphological changes, 11 ring-shaped ligaments in corpses without a common pathology and local manifestations of the hand were examined. Results. In untreated patients (group I), with an increase in the duration of the disease, signs of lymphocyte-cell infiltration, edema of the ring-shaped ligament and distrofic-degenerative changes accompanied by a decrease in the fibrillar component and the appearance of chondrogenic foci increased. In patients of the second group, the pathological process was characterized by the lymphocyte-fibroblastic phase of independence from the duration of the disease. At the same time, changes in the cellular composition of fibrous connective tissue prevailed. Conclusion . In patients of group I, an increase in the specific area of the main amorphous substance was determined 7.92 times and 2.57 times the macrophage-lymphocytic infiltrates of endothendinia and perithendinium, and in endothendia they were accompanied by collagenolysis and foci of ectopic chondrogenesis. In patients of group II, the proportion of the area of endothendia increased by 42.46% due to early violations of the architecture of the ligament fibers and lymphocytic infiltration; in the epithendia, the hypercellular regions were determined with dense hyperchromicfibrocytes. After 12 months The specific area of the endothendia increased by 4.76 times.