Repairing and regenerating damaged tissues or organs, and restoring their functioning has been the ultimate aim of medical innovations. 'Reviving healthcare' blends tissue engineering with alternative techniques such as hydrogels, which have emerged as vital tools in modern medicine. Additive manufacturing (AM) is a practical manufacturing revolution that uses building strategies like molding as a viable solution for precise hydrogel manufacturing. Recent advances in this technology have led to the successful manufacturing of hydrogels with enhanced reproducibility, accuracy, precision, and ease of fabrication. Hydrogels continue to metamorphose as the vital compatible bio-ink matrix for AM. AM hydrogels have paved the way for complex 3D/4D hydrogels that can be loaded with drugs or cells. Bio-mimicking 3D cell cultures designed via hydrogel-based AM is a groundbreaking in-vivo assessment tool in biomedical trials. This brief review focuses on preparations and applications of additively manufactured hydrogels in the biomedical spectrum, such as targeted drug delivery, 3D-cell culture, numerous regenerative strategies, biosensing, bioprinting, and cancer therapies. Prevalent AM techniques like extrusion, inkjet, digital light processing, and stereo-lithography have been explored with their setup and methodology to yield functional hydrogels. The perspectives, limitations, and the possible prospects of AM hydrogels have been critically examined in this study.
- MeSH
- Printing, Three-Dimensional MeSH
- Bioprinting methods MeSH
- Cell Culture Techniques MeSH
- Hydrogels * chemistry MeSH
- Drug Delivery Systems MeSH
- Humans MeSH
- Cell Culture Techniques, Three Dimensional methods MeSH
- Tissue Engineering * methods MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
OBJECTIVE: The perineal body connects muscles from the pelvic floor and is critical for support of the lower part of the vagina and proper function of the anal canal. We determined mechanical parameters and volume fractions of main components of the human female postmenopausal perineal body. METHODS: The specimens were taken from 15 fresh female cadavers (age 74 ± 10, mean ± standard deviation). Seventy-five specimens from five regions of the perineal body were processed histologically to assess volume fractions of tissue components using stereological point testing grid. Fifteen specimens taken from the midline region were loaded uniaxially with 6 mm/min velocity until tissue rupture to determine Young's modulus of elasticity, ultimate stresses, and strains. RESULTS: The perineal body was composed of collagen (29%), adipose cells (27%), elastin (7%), smooth muscle (11%), and skeletal muscle (3%). The residual tissue (19%) constituted mostly peripheral nerves, lumina of blood vessels, fibroblasts, and fibrocytes. Young's modulus of elasticity at midline region was 18 kPa (median) at small and 232 kPa at large deformations, respectively. The ultimate stress was 172 kPa and the ultimate strain was 1.4. CONCLUSIONS: We determined the structural and mechanical parameters of the perineal body. The resultant data could be used as input for models simulating pelvic floor prolapse or dysfunction.
- MeSH
- Anal Canal MeSH
- Biomechanical Phenomena physiology MeSH
- Elastin analysis MeSH
- Muscle, Smooth anatomy & histology MeSH
- Collagen analysis MeSH
- Muscle, Skeletal anatomy & histology MeSH
- Middle Aged MeSH
- Humans MeSH
- Cadaver MeSH
- Pelvic Floor anatomy & histology physiology surgery MeSH
- Perineum anatomy & histology physiology surgery MeSH
- Postmenopause physiology MeSH
- Pelvic Organ Prolapse physiopathology MeSH
- Elasticity physiology MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Adipose Tissue anatomy & histology MeSH
- Vagina MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
In this study, nanoparticle-incorporated nanofiber-covered yarns were prepared using a custom-made needle-free electrospinning system. The ultimate goal of this work was to prepare functional nanofibrous surfaces with antibacterial properties and realize high-speed production. As antibacterial agents, we used various amounts of copper oxide (CuO) and vanadium (V) oxide (V2O5) nanoparticles (NPs). Three yarn preparation speeds (100 m/min, 150 m/min, and 200 m/min) were used for the nanofiber-covered yarn. The results indicate a relationship between the yarn speed, quantity of NPs, and antibacterial efficiency of the material. We found a higher yarn speed to be associated with a lower reduction in bacteria. NP-loaded nanofiber yarns were proven to have excellent antibacterial properties against Gram-negative Escherichia coli (E. coli). CuO exhibited a greater inhibition and bactericidal effect against E. coli than V2O5. In brief, the studied samples are good candidates for use in antibacterial textile surface applications, such as wastewater filtration. As greater attention is being drawn to this field, this work provides new insights regarding the antibacterial textile surfaces of nanofiber-covered yarns.
- MeSH
- Anti-Bacterial Agents chemistry MeSH
- Copper chemistry MeSH
- Nanofibers chemistry MeSH
- Polyvinyls chemistry MeSH
- Vanadium chemistry MeSH
- Publication type
- Journal Article MeSH
Dental implant dimensions, and bone quality and quantity play a key role in early osseointegration and long-term prognosis in posterior edentulous maxilla. Treatment with short implants, preferably in a bicortical manner, is an accepted modality; however, short implants have limitations leading to increased stress concentrations in alveolar bone, potential overload and implant failure. Implant models of 3.3, 4.1, 4.8 and 5.4 mm diameter and 4.5, 5.5, 6.5, 7.5 and 8.5 mm length were placed in posterior maxilla 3-D models with corresponding residual bone heights. Bone-implant assemblies were analyzed in finite element software ANSYS 15. All materials were assumed to be linearly elastic and isotropic. 118.2 N oblique loading was applied to investigate stress distributions in bone tissues. The concept of ultimate functional load (UFL) was selected as a criterion to compare load-carrying capacity of implants and to evaluate the influence of available bone height and implant dimensions on load-carrying capacity. For all implants, UFL was calculated by limiting von Mises stresses in cortical or cancellous bone with bone strength (100 MPa for cortical and 2 MPa for cancellous bone). Implant load-carrying capacity depends on diameter and available bone height. Wide implants have higher load-carrying capacity than narrow implants. Short implants with proper diameter and length avoid bone overstress, even in Type IV bone.
- MeSH
- Finite Element Analysis * MeSH
- Humans MeSH
- Maxilla * physiology MeSH
- Osseointegration MeSH
- Materials Testing * MeSH
- Weight-Bearing MeSH
- Dental Implants * MeSH
- Dental Prosthesis Design MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
PURPOSE OF THE STUDY The aim of the study was to present the surgical technique combining the interposition and suspension arthroplasty using the TIE-IN implant as a treatment option for advanced symptomatic to final stage rhizarthrosis. MATERIAL AND METHODS Since 2015 we have performed the interposition arthroplasty combined with suspension arthroplasty using the TIE-IN implant in 12 patients, mostly indicated for stage IV rhizarthrosis. In two cases stage III rhizarthrosis with concomitant trapezium destruction was present. In two other cases the patients suffered from secondary osteoarthrosis associated with rheumatoid arthritis. Pain under loads was present in all the patients, of whom in 10 patients also the pain at rest occurred. Preoperatively, a total of 10 patients showed subluxation of the first carpometacarpal joint of 50% of the articular surface width. The ratio between the dominant and non-dominant extremity was 1:1. As a part of the evaluation, correlation was established between the preoperative findings and the postoperative results at 3 months follow-up. The examination included the assessment of pain intensity by VAS scale, the range of motion measurement - by Kapandji thumb opposition test, handgrip strength test and functional evaluation using the scoring systems - DASH score, modified DASH score for thumb, and modified Wrightington score. RESULTS No intraoperative or postoperative complications such as infection, complex regional pain syndrome, implant failure or failed surgical procedure were reported in the given group of patients. The pain at rest ceased in all 12 patients. The VAS pain intensity score improved from the preoperative average of 5.8 to 0.8 postoperatively. The range of motion in all the patients with stage IV rhizarthrosis substantially improved. The average Kapandji thumb opposition score increased from 6.9 preoperatively to 9.5 postoperatively. DISCUSSION There are multiple surgical treatment options for advanced rhizarthrosis. Apart from the combination of interposition and suspension arthroplasty referred to above, it is trapeziometacarpal (TMC) arthrodesis on the one hand and carpometacarpal joint total arthroplasty on the other hand. The arthrodesis continues to be a fairly frequently used procedure, despite the final limitation of thumb movement. It is because of this loss of fine motor function why it is not the preferred technique for treating advanced rhizarthrosis at our department. On the very contrary, the total replacement of the TMC joint is at our department as well as at many other departments the treatment of choice for advanced symptomatic rhizarthrosis since in conservative resection of the articular surfaces the biomechanics of the carpometacarpal joint of the thumb is preserved. As an outcome, this technique combines the advantages of other surgical methods by ensuring full painless range of motion and strength of the joint as opposed to other techniques, which mostly result either in a limited movement, or in a loss of grip strength. There is a whole range of resection arthroplasty techniques available. From simple trapeziectomy, which leads to the radial column collapse and ultimately to a major functional deficit, up to various interposition or suspension arthroplasty techniques with the resulting range of motion, stability and thus grip strength depending on the technique applied. CONCLUSIONS By applying the combination of the interposition and suspension arthroplasty of the carpometacarpal joint of the thumb using the TIE-IN implant we preserve the length of the thumb, its stability, and thus achieve the recovery of adequate thumb range of motion and grip strength. Our conclusions are in correlation with the results obtained at reference centres. Key words:rhizarthrosis, trapeziometacarpal prosthesis, arthroplasty, trapezium implant.
- MeSH
- Arthroplasty, Replacement adverse effects instrumentation methods MeSH
- Carpometacarpal Joints physiopathology surgery MeSH
- Middle Aged MeSH
- Humans MeSH
- Pain Measurement MeSH
- Osteoarthritis physiopathology surgery MeSH
- Thumb surgery MeSH
- Postoperative Complications MeSH
- Joint Prosthesis * MeSH
- Range of Motion, Articular MeSH
- Aged MeSH
- Hand Strength MeSH
- Trapezium Bone surgery MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Aged MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: For dental implant success, experimentally established thresholds should limit bone stresses and strains. From these metrics, the ultimate functional load, which determines the implant load-carrying capacity, can be calculated. Obviously, its decrease due to bone loss shortens implant service life. A comparison of how bone loss affects the ultimate functional loads of various implants can provide the clinician with meaningful feedback concerning the suitability and longevity of implants. The aim of this study is to evaluate the lifetime of different dental implants placed in I-IV bone types on the basis of a comparison of their ultimate functional loads with consideration of the bone loss factor. METHOD: Von Mises stress and first principal strain distributions in bone-implant interface were studied and ultimate functional loads were calculated. Models of I-IV bone types were designed. 3.3 × 8.0 mm (A), 4.1 × 12.0 mm (B) and 4.8 × 14.0 mm (C) implants were analyzed at 10 levels of bone loss. Ultimate functional loads, which generated the ultimate von Mises stress and first principal strain in bone, were computed. RESULTS: For the implants A, B, and C placed in type I bone, ultimate functional load values were above 120.92 N experimental functional load, which corresponded to 10+, 10+, and 10 + years of service with 0.2 mm annual bone loss. For type II bone, the lifetime was 4, 10+, and 10 + years. For type III bone, the lifetime was 4, 5, and 5 years. For type IV bone, first principal strains were initially deleterious for all implants. CONCLUSIONS: In oral implantology, bone loss is an essential factor for implant longevity prognosis. While evaluating implant load-carrying capacity, clinicians should take into account the factor of implant longevity decrease.
- MeSH
- Finite Element Analysis MeSH
- Models, Biological MeSH
- Biomechanical Phenomena physiology MeSH
- Humans MeSH
- Stress, Mechanical MeSH
- Alveolar Bone Loss epidemiology MeSH
- Treatment Outcome MeSH
- Dental Implants statistics & numerical data MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Dental implant failure is mainly the consequence of bone loss at peri-implant area. It usually begins in crestal bone. Due to this gradual loss, implants cannot withstand functional force without bone overload, which promotes complementary loss. As a result, implant lifetime is significantly decreased. To estimate implant success prognosis, taking into account 0.2 mm annual bone loss for successful implantation, ultimate occlusal forces for the range of commercial cylindrical implants were determined and changes of the force value for each implant due to gradual bone loss were studied. For this purpose, finite element method was applied and von Mises stresses in implant-bone interface under 118.2 N functional occlusal load were calculated. Geometrical models of mandible segment, which corresponded to Type II bone (Lekholm & Zarb classification), were generated from computed tomography images. The models were analyzed both for completely and partially osseointegrated implants (bone loss simulation). The ultimate value of occlusal load, which generated 100 MPa von Mises stresses in the critical point of adjacent bone, was calculated for each implant. To estimate longevity of implants, ultimate occlusal loads were correlated with an experimentally measured 275 N occlusal load (Mericske-Stern & Zarb). These findings generally provide prediction of dental implants success.
- MeSH
- Finite Element Analysis * MeSH
- Dental Stress Analysis MeSH
- Time Factors MeSH
- Humans MeSH
- Mandible pathology MeSH
- Stress, Mechanical MeSH
- Osseointegration MeSH
- Bite Force MeSH
- Weight-Bearing MeSH
- Imaging, Three-Dimensional MeSH
- Dental Implants * MeSH
- Dental Prosthesis Design MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Myocardial remodeling driven by excess pressure and volume load is believed to be responsible for the vicious cycle of progressive myocardial dysfunction in chronic heart failure. Left ventricular assist devices (LVADs), by providing significant volume and pressure unloading, allow a reversal of stress-related compensatory responses of the overloaded myocardium. Herein, we summarize and integrate insights from studies which investigated how LVAD unloading influences the structure and function of the failing human heart. RECENT FINDINGS: Recent investigations have described the impact of LVAD unloading on key structural features of cardiac remodeling - cardiomyocyte hypertrophy, fibrosis, microvasculature changes, adrenergic pathways and sympathetic innervation. The effects of LVAD unloading on myocardial function, electrophysiologic properties and arrhythmias have also been generating significant interest. We also review information describing the extent and sustainability of the LVAD-induced myocardial recovery, the important advances in understanding of the pathophysiology of heart failure derived from such studies, and the implications of these findings for the development of new therapeutic strategies. Special emphasis is given to the great variety of fundamental questions at the basic, translational and clinical levels that remain unanswered and to specific investigational strategies aimed at advancing the field. SUMMARY: Structural and functional reverse remodeling associated with LVADs continues to inspire innovative research. The ultimate goal of these investigations is to achieve sustained recovery of the failing human heart.
- MeSH
- Endothelium, Vascular MeSH
- Extracellular Matrix MeSH
- Fibrosis MeSH
- Financing, Organized MeSH
- Cardiomegaly MeSH
- Myocytes, Cardiac MeSH
- Humans MeSH
- Microvessels pathology MeSH
- Myocardium pathology MeSH
- Heart-Assist Devices MeSH
- Ventricular Remodeling MeSH
- Heart Ventricles MeSH
- Heart Failure pathology MeSH
- Sympathetic Nervous System MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
Summary: Dental implants have been considered to be a successful treatment modality. Recently, achieving a good osseointegration is not the ultimate goal for the restorative dentist. Successful implant treatment demands the best gingival esthetic success along with stability and function of the implant. This study was performed to obtain answers to some controversial points pertaining to esthetics and function of implants in maxilla. Immediate flapless implantation into the extraction sockets in maxillary anterior zone is an emerging treatment option in dentistry- the esthetic success of which was in debate for long. The proposed study compared the esthetic success of immediate flapless implants (ILA), to immediate implants with the need for flap (ILB) and, delayed implants (DSL) in single tooth restorations, in the anterior region of the maxilla. The other aim of the study was to find out if any relation exists between the interproximal crestal bone height and papilla height. Analysis was done irrespective of treatment procedure in the same study group using periodontal sounding and radiographs to find out the relation. From the study involving 106 participants, including 21 ILA, 22 ILB and 63 DSL cases, we received highest papillary index score of 2.6 average from group ILA, followed by ILB and DSL, after 3 months of prosthetic loading. From the periodontal sounding and radiographic study it was evident that, when the distance between the base of the contact point of crowns and height of interproximal bone was less than 5, the papilla was present 100 % of the time, but when the distance increased to 6 and more than 7 mm, the papilla was present only 46.5 and 24 percentage of the time respectively.
Předložená práce ověřuje hypotézu, podle níž existují V haverské kostní tkáni dva typy osteonů, „tahové" a „tlakové". „Tahové" osteony mají vznikat pod vlivem tahu a mají mít vyšší pevnost v tahu. Opak má platit pro osteony „tlakové". V předložených experimentech byla porovnávána pevnost kostní tkáně v tahu i tlaku na vzorcích z mediální stěny diafýzy femuru, vystavené in vivo tlaku, s pevností vzorků z laterální stěny, vystavené tahu. Vzorky byly připraveny tak, aby se jejich dlouhá osa, ve které byly vzorky zatěžovány, kryla se směrem osteonů.Ty totiž nejsou u femuru orientovány v podélněm směru, ale vytvářejí dva šroubovicové antirotační systémy, umístěné v protilehlých stěnách diafýzy. Orientace osteonů byla určena po náplni haverských kanálů tuší podle vlastní metody autorů.
The underlying study tests the hypothesis on the existence of two types of osteons, the "tension" and the "pressure" ones. Osteons of the first type should be built under the influence of tension and should manifest greater strength in tension. The contrary applies to the "pressure" osteons. The ultimate strength of the bone tissue in tension and compression was studied on samples from the medial wall of the femoral diaphysis, subjected in Vivo to compression, and on samples from the lateral wall, subjected to tension. All samples were manufactured with the long axis corresponding to the orientation of osteons, arranged in two helical antirotary systems situated in the contralateral walls of the diaphysis. The osteon orientation was ascertained after filling vascular canals with India-ink. The bone samples were tested using the Schenk Trebel RM10-K machine. Tension tests found no difference in bone strength between samples from the lateral and from the medial walls. In compression tests, three cases manitested greater strength in samples from the medial wall, two cases in samples from the lateral wall. Such results speak against the hypothesis of the existence of two functional types of osteons. A complementary series of experiments showed that the tension strength is greatest in samples hading a longitudinal orientation of osteons and that it decreases rapidly with growing inclination of osteons from the axis of loading. The dominant factor, responsible for the bone strength, is therefore the osteon orientation and not the mode of mechanical loading in vivo or the orientation of collagen fibres.
- MeSH
- Biomechanical Phenomena MeSH
- Femur MeSH
- Bone and Bones analysis physiology blood supply MeSH
- Humans MeSH
- Tensile Strength MeSH
- Pressure MeSH
- Check Tag
- Humans MeSH
- Publication type
- Comparative Study MeSH
