scholarly journals Neovascularization in Meniscus and Tendon Pathology as a Potential Mechanism in Regenerative Therapies: Special Reference to Platelet-Rich Plasma Treatment

2021 ◽  
Vol 11 (18) ◽  
pp. 8310
Author(s):  
Dawid Szwedowski ◽  
Łukasz Jaworski ◽  
Wioleta Szwedowska ◽  
Przemysław Pękala ◽  
Maciej Gagat

Neovascularization is a complex, multistep process that includes the activation of endothelial cells, degradation of the basement membrane surrounding the blood vessel, formation of tip cells, the sprouting, migration and proliferation of endothelial cells into the interstitial space, and then the generation of space in the matrix to allow for the formation of a new, proper lumen of a newly formed blood vessel. Abundant neovascularization can be found in tendinous tissue obtained from asymptomatic athletes or the meniscus early after the injury. The concept of neovascularization in musculoskeletal system disorders seems to be mainly associated with pain and poor clinical outcomes. On the one hand, this phenomenon allows for tissue regeneration, but on the other, it is present during the degeneration process in connective tissue. Establishing the current concept on neovascularization is also needed. A narrative review of the current literature was conducted using databases including Embase, PubMed and Cochrane. This review aims to investigate the exact role of the neovascularization process in tendon and meniscus lesions and its role as a potential target in clinics, specifically in platelet-rich plasma (PRP) therapy. The stabilization of the neovessels required to achieve the healed tissue, together with the standardization of the PRP injections, can offer an alternative future therapeutic approach for the treatment of tendinopathy and meniscal injuries.

Author(s):  
M. R. Pinnel ◽  
A. Lawley

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.


1984 ◽  
Vol 51 (03) ◽  
pp. 385-387 ◽  
Author(s):  
Clive J Dix ◽  
David G Hassall ◽  
K Richard Bruckdorfer

SummaryPlatelet-rich plasma was obtained 24 hr after the race ended from athletes who ran in the London marathon. The platelets were only marginally less sensitive to adrenaline than were those of non-runners using conventional aggregation tests. However, the runners’ platelets were much more sensitive to inhibition by prostacyclin, a prostaglandin synthesized by endothelial cells. It appeared that this effect was due to a greater activity in the platelets of the membrane-bound adenylate cyclase enzyme which generates intracellular cyclic AMP. Cyclic AMP production is known to be stimulated by prostacyclin and to cause the inhibition of platelet aggregation. The results indicate another possible protective effect of exercise against cardiovascular disease which is independent of the known changes in lipoprotein concentrations previously observed in athletes.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Ashoke Sen

Abstract In a recent paper, Balthazar, Rodriguez and Yin found remarkable agreement between the one instanton contribution to the scattering amplitudes of two dimensional string theory and those in the matrix model to the first subleading order. The comparison was carried out numerically by analytically continuing the external energies to imaginary values, since for real energies the string theory result diverges. We use insights from string field theory to give finite expressions for the string theory amplitudes for real energies. We also show analytically that the imaginary parts of the string theory amplitudes computed this way reproduce the full matrix model results for general scattering amplitudes involving multiple closed strings.


2021 ◽  
Vol 22 (6) ◽  
pp. 2804
Author(s):  
Yasuo Yoshitomi ◽  
Takayuki Ikeda ◽  
Hidehito Saito-Takatsuji ◽  
Hideto Yonekura

Blood vessels are essential for the formation and maintenance of almost all functional tissues. They play fundamental roles in the supply of oxygen and nutrition, as well as development and morphogenesis. Vascular endothelial cells are the main factor in blood vessel formation. Recently, research findings showed heterogeneity in vascular endothelial cells in different tissue/organs. Endothelial cells alter their gene expressions depending on their cell fate or angiogenic states of vascular development in normal and pathological processes. Studies on gene regulation in endothelial cells demonstrated that the activator protein 1 (AP-1) transcription factors are implicated in angiogenesis and vascular development. In particular, it has been revealed that JunB (a member of the AP-1 transcription factor family) is transiently induced in endothelial cells at the angiogenic frontier and controls them on tip cells specification during vascular development. Moreover, JunB plays a role in tissue-specific vascular maturation processes during neurovascular interaction in mouse embryonic skin and retina vasculatures. Thus, JunB appears to be a new angiogenic factor that induces endothelial cell migration and sprouting particularly in neurovascular interaction during vascular development. In this review, we discuss the recently identified role of JunB in endothelial cells and blood vessel formation.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 816
Author(s):  
Yuxuan Ge ◽  
Zhenhua Hu ◽  
Jili Chen ◽  
Yujie Qin ◽  
Fei Wu ◽  
...  

GLP-1 receptor agonists are a class of diabetes medicines offering self-regulating glycemic efficacy and may best be administrated in long-acting forms. Among GLP-1 receptor agonists, exenatide is the one requiring the least dose so that controlled-release poly(d, l-lactic-co-glycolic acid) (PLGA) microspheres may best achieve this purpose. Based on this consideration, the present study extended the injection interval of exenatide microspheres from one week of the current dosage form to four weeks by simply blending Mg(OH)2 powder within the matrix of PLGA microspheres. Mg(OH)2 served as the diffusion channel creator in the earlier stage of the controlled-release period and the decelerator of the self-catalyzed degradation of PLGA (by the formed lactic and glycolic acids) in the later stage due to its pH-responsive solubility. As a result, exenatide gradually diffused from the microspheres through Mg(OH)2-created diffusion channels before degradation of the PLGA matrix, followed by a mild release due to Mg(OH)2-buffered degradation of the polymer skeleton. In addition, an extruding–settling process comprising squeezing the PLGA solution through a porous glass membrane and sedimentation-aided solidification of the PLGA droplets was used to prepare the microspheres to ensure narrow size distribution and 95% encapsulation efficiency in an aqueous continuous phase. A pharmacokinetic study using rhesus monkey model confirmed the above formulation design by showing a steady blood concentration profile of exenatide with reduced CMAX and dosage form index. Mg·(OH)2


Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1531-1534 ◽  
Author(s):  
LA Sporn ◽  
VJ Marder ◽  
DD Wagner

Abstract Large multimers of von Willebrand factor (vWf) are released from the Weibel-Palade bodies of cultured endothelial cells following treatment with a secretagogue (Sporn et al, Cell 46:185, 1986). These multimers were shown by immunofluorescent staining to bind more extensively to the extracellular matrix of human foreskin fibroblasts than constitutively secreted vWf, which is composed predominantly of dimeric molecules. Increased binding of A23187-released vWf was not due to another component present in the releasate, since releasate from which vWf was adsorbed, when added together with constitutively secreted vWf, did not promote binding. When iodinated plasma vWf was overlaid onto the fibroblasts, the large forms bound preferentially to the matrix. These results indicated that the enhanced binding of the vWf released from the Weibel-Palade bodies was likely due to its large multimeric size. It appears that multivalency is an important component of vWf interaction with the extracellular matrix, just as has been shown for vWf interaction with platelets. The pool of vWf contained within the Weibel-Palade bodies, therefore, is not only especially suited for platelet binding, but also for interaction with the extracellular matrix.


1993 ◽  
Vol 6 (1) ◽  
pp. 61-80 ◽  
Author(s):  
John D'Arcy May

Do human rights in their conventional, Western understanding really meet the needs of Pacific peoples? This article argues that land rights are a better clue to those needs. In Aboriginal Australia, Fiji, West Papua and Papua New Guinea, case studies show that people's relationship to land is religious and implicitly theological. The article therefore suggests that rights to land need to be supplemented by rights of the land extending to the earth as the home of the one human community and nature as the matrix of all life.


2016 ◽  
Vol 43 ◽  
pp. 303-313 ◽  
Author(s):  
Fang Zhou ◽  
Xiaoling Jia ◽  
Yang Yang ◽  
Qingmao Yang ◽  
Chao Gao ◽  
...  

2017 ◽  
Vol 65 (4) ◽  
pp. 359-367 ◽  
Author(s):  
Giulia Tarquinio DEMARCO ◽  
Laura Borges KIRSCHNICK ◽  
Luis Bayardo WATSON ◽  
Marcus Cristian MUNIZ CONDE ◽  
Flávio Fernando DEMARCO ◽  
...  

ABSTRACT Regenerative therapies have been widely developed in dentistry and it is important to incorporate dentists’ knowledge of these new therapies into the dental clinic routine. This study reviewed the literature on regenerative therapies and clinical applications. Tissue engineering has contributed to changes in the paradigm of restorative health sciences. Its pillars underpin the techniques of tissue and organ regeneration. Despite the majority of studies in this field being in vitro, a range of preclinical studies and methodologies has been formed using these principles and they are already being used on humans. The use of platelet-rich plasma and platelet-rich fibrin in surgery as natural scaffolds for the reestablishment of bone and periodontal tissue are often reported in the literature and clinical trials using this approach have shown promising results. Stem cells from autologous dental pulp have been successfully applied in bone tissue regeneration using natural collagen scaffold in humans. In addition, revascularization of the root canal already appears in the literature as a promising alternative to apexification. The principle behind this therapy is the use of the blood clot as a scaffold and the migration of stem cells of the apical papilla to regenerate the dental pulp organ. Final considerations: Although still in the early stages, regenerative therapies can now be used in dental practice. Knowledge of the principles governing these therapies should be understood by the dentist for use in clinical practice.


Author(s):  
Ori Soltes

Religious and cultural syncretism, particularly in visual art in the Jewish and Christian traditions since the 19th century, has expressed itself in diverse ways and reflects a broad and layered series of contexts. These are at once chronological—arising out of developments that may be charted over several centuries before arriving into the 19th and 20th centuries—and political, spiritual, and cultural, as well as often extending beyond the Jewish–Christian matrix. The specific directions taken by syncretism in art is also varied: it may be limited to the interweave of two religious traditions—most often Jewish and Christian—in which most often it is the minority artist seeking ways to create along lines consistent with what is created by the majority. It may also interweave three or more traditions. It may be a matter of religion alone, or it may be a matter of other issues, such as culture or gender, which may or may not be obviously intertwined with religion. The term “syncretism” has, in certain specifically anthropological and theological circles, acquired a negative connotation. This has grown out of the increasing consciousness, since the 1960s, of the political implications of that term in the course of Western history, in which hegemonic European Christianity has addressed non-Christian religious perspectives. This process intensified in the Colonial era when the West expanded its dominance over much of the globe. An obvious and particularly negative instance of this is the history of the Inquisition as it first affected Jews in late-15th-century Spain and later encompassed indigenous peoples in the Americas, Asia, and Africa. While this issue is noted—after all, art has always been interwoven with politics—it is not the focus of this article. Instead “syncretism” will not be treated as a concept that needs to be distinguished from “hybridization” or “hybridity,” although different modes of syncretism will be distinguished. Syncretistic preludes to visual artists in the 19th and 20th centuries, suggesting some of the breadth of possibility, include Pico della Mirandola, Kabir, and Baruch/Benedict Spinoza. Specific religious developments and crises in Europe from the 16th century to the 18th century brought on the emancipation of the Jews in some places on the one hand, and a contradictory continuation of anti-Jewish prejudice on the other, the latter shifting from a religious to a racial basis. This, together with evident paradoxes regarding secular and spiritual perspectives in the work of key figures in the visual arts, led to a particularly rich array of efforts from Jewish artists who revision Jesus as a subject, applying a new, Jewishly humanistic perspective to transform this most traditional of Christian subjects. Such a direction continued to spread more broadly across the 20th century. The Holocaust not only raised new visual questions and possibilities for Jewish artists, but also did so from the opposite direction for the occasional Christian—particularly German—artist. Cultural syncretism sometimes interweaves religious syncretism—which can connect and has connected Christianity or Judaism to Eastern religions—and a profusion of women artists in the last quarter of the century has added gender issues to the matrix. The discussion culminates with Siona Benjamin: a Jewish female artist who grew up in Hindu and Muslim India, attended Catholic and Zoroastrian schools, and has lived in America for many decades—all these aspects of her life resonate in her often very syncretistic paintings.


Sign in / Sign up

Export Citation Format

Share Document