The effects of combined low level laser therapy and mesenchymal stem cells on bone regeneration in rabbit calvarial defects

Abstract: This study evaluated the effect of Low Level Laser Therapy (LLLT) and Mesenchymal Stem Cells (MSCs) on bone regeneration. Background data: Although several studies evaluated the effects of MSCs and LLLT, there is little information available regarding in vivo application of LLLT in conjunction with MSCs. Methods: Forty-eight circular bone defects (6 mm in diameter) were prepared in the calvaria of 12 New- Zealand white rabbits. The defects of each animal were randomly assigned to 4 groups: (C) no treatment; (L) applying LLLT; (SC) filled with MSCs; (SCL) application of both MSCs and LLLT. LLL was applied on alternate days at wavelength of 810 nm, power density of 0.2 W/cm2 and a fluency of 4 J/cm2 using a Gallium–Aluminum–Arsenide (GaAlAs) diode laser. The animals were sacrificed after 3 weeks and then histological samples were evaluated to determine the amount of new bone formation and the remaining scaffold and inflammation. Results: The histological evaluation showed a statistically significant increase in new bone formation of LLLT group relative to the control and the other two experimental groups (p < 0.05). There was no significant difference in bone formation of the control group compared to experimental groups filled with MSCs. Laser irradiation had no significant effect on resorption of the scaffold material. In addition, inflammation was significantly reduced in LLLT group compared to the control defects and the other two experimental groups. Conclusion: Low level laser therapy could be effective in bone regeneration but there is no evidence of a synergistic effect when applied in conjunction with MSCs

Preclinical studies of166Ho-chitosan for treatment of hepatocellular carcinoma

Introduction: Recently, due to the special characteristics of166Ho and chitosan,166Ho-chitosan complex was developed for treatment of tumors such as hepatocellular carcinoma. This complex has been lately prepared with high radiochemical purity in our lab. The preclinical studies of the complex however should be performed to evaluate the tracer concentration in target and normal tissues before human use. Methods: In this study,166Ho-chitosan was prepared and its preclinical studies for treatment of hepatocellular carcinoma was carried out by injection of the radiopharmaceutical into the rabbit's liver via two different methods, surgery and venography. Leakage of the injected activity from the injection site in the rabbit organs was investigated using SPECT and SPECT-CT imaging up to 24 hours. Results: Both SPECT and SPECT-CT imaging of the rabbits showed that there was no significant leakage of the injected activity. Almost all the activity would remain in the injection site at least 24 h post injection. Conclusion: Considering all of the excellent features of the complex, this radiopharmaceutical is suggestive for treatment of hepatocellular carcinoma by radioembolization method

Amniotic membrane seeded with mesenchymal adipose-derived stem cell for coverage of wound in third degree burn: An experimental study

Methods: This study was experimental and has been done in Burn Research Center of Iran University of Medical Sciences during January 2012 to April 2013. Thirty rats randomly divided to three equal groups. Inguinal fat of 10 rats (one group) were used for preparation of autologous adipose-derived mesenchymal stem cells. Acellular amnion was used as a scaffold for stem cell transfer. Each of the thirty rats had been exposed to a cm deep 3rd degree burn on back area. 24 hours after surgery, the wound was excised and it had been covered by three methods: conventional dressing in the first group, acellular amnion in the second group and acellular amnion seeded with adipose-derived stem cell in the third group. The rate of wound healing and pathologic characteristics was compared in all three groups. Results: Healing rate and decrease in wounds size was significantly better in acellular amnion seeded with adipose- derived stem cells compared with other two groups at 3rd and 15th days after surgery P&lt;0.01. Also in histopathology examination, fibroplasia and neovascularization of wounds were significantly better in stem cells group than the other two groups P&lt;0.001. Conclusion: Acellular amnion seeded with adipose-derived stem cell can result in faster wound healing and better histopathology characteristic. The amnion as a scaffold and the fat derived stem cells as healing accelerator are recommended for coverage of the 3rd degree burn wounds after excision and it may reduce the need for skin graft. Background: Stem cells are applied in the treatment of wide range of diseases and can be separated from different tissues of the body. These cells can treat diseases by cytokine and growth factor secretion and also cell differentiation. Burn wound is a challenging problem of reconstructive surgery and stem cells may help wound healing process. We designed this study to evaluate the beneficial effect of fat derived stem cells for coverage of 3rd degree burn wound. © 2014, Tehran University of Medical Sciences (TUMS). All rights reserved

Effects of Photobiomodulation and Mesenchymal Stem Cells on Articular Cartilage Defects in a Rabbit Model

Objective: The aim of this study was to evaluate the effectiveness of the application of cultured autologous bone marrow mesenchymal stem cells (BMSCs) with scaffold and low-level laser therapy (LLLT) on the repair of articular cartilage defects in rabbits. Background data: For healing of the articular cartilage defects, although positive effects of BMSCs and LLLT have been demonstrated, their combination effect is still unknown; therefore, we investigated combining these two techniques has a synergistic effect. Materials and methods: After bone marrow aspiration from 10 rabbits, BMSCs were isolated, cultured in monolayer, suspended on a type I collagen scaffold and then implanted onto a full-thickness osteochondral defect (4 mm in diameter), artificially made on the patellar groove of both knees in the same rabbits. Then a knee was selected randomly in each rabbit as the experimental group, and subjected to Ga-Al-As (810 nm) laser irradiation with energy density of 4 J/cm2 every other day for 3 weeks. As the control group, the other knee did not receive LLLT. After this period, animals were euthanized and osteochondral defects were evaluated by histomorphometric methods. Results: No significant difference in new cartilage formation and inflammation was found between the groups (p > 0.05). However, there was significantly more new bone formation in the experimental group (p < 0.05). Conclusions: In terms of our research, although better healing in osteochondral defects was seen when combining BMSCs and LLLT compared with the use of BMSCs alone, this improvement was predominantly caused by new bone formation rather than new cartilage formation. © 2016, Mary Ann Liebert, Inc

Modelling duality between bound and resonant meson spectra by means of free quantum motions on the de Sitter space-time dS4

The real parts of the complex squared energies defined by the resonance poles of the transfer matrix of the Pöschl-Teller barrier, are shown to equal the squared energies of the levels bound within the trigonometric Scarf well potential. By transforming these potentials into parts of the Laplacians describing free quantum motions on the mutually orthogonal open-time-like hyperbolic-, and closed-space-like spherical geodesics on the conformally invariant de Sitter space-time, dS4, the conformal symmetries of these interactions are revealed. On dS4 the potentials under consideration naturally relate to interactions within colorless two-body systems and to cusped Wilson loops. In effect, with the aid of the dS4 space-time as unifying geometry, a conformal symmetry based bijective correspondence (duality) between bound and resonant meson spectra is established at the quantum mechanics level and related to confinement understood as color charge neutrality. The correspondence allows to link the interpretation of mesons as resonance poles of a scattering matrix with their complementary description as states bound by an instantaneous quark interaction and to introduce a conformal symmetry based classification scheme of mesons. As examples representative of such a duality we organize in good agreement with data 71 of the reported light flavor mesons with masses below ∼ 2350 MeV into four conformal families of particles placed on linear f0, $\pi$ , $\eta$ , and a0 resonance trajectories, plotted on the ℓ/M plane. Upon extending the sec2 $\chi$ by a properly constructed conformal color dipole potential, shaped after a tangent function, we predict the masses of 12 “missing” mesons. We furthermore notice that the f0 and $\pi$ trajectories can be viewed as chiral partners, same as the $\eta$ and a0 trajectories, an indication that chiral symmetry for mesons is likely to be realized in terms of parity doubled conformal multiplets rather than, as usually assumed, only in terms of parity doubled single SO(3) states. We attribute the striking measured meson degeneracies to conformal symmetry dynamics within color neutral two-body systems, and conclude on the usefulness of the de Sitter space-time, dS4, as a tool for modelling strong interactions, on the one side, and on the relevance of hyperbolic and trigonometric potentials in constituent quark models of hadrons, on the other

Addendum to: Modelling duality between bound and resonant meson spectra by means of free quantum motions on the de Sitter space-time dS

In the article under discussion the analysis of the spectra of the unflavored mesons lead us to some intriguing insights into the possible geometry of space-time outside the causal Minkowski light cone and into the nature of strong interactions. In applying the potential theory concept of geometrization of interactions, we showed that the meson masses are best described by a confining potential composed by the centrifugal barrier on the three-dimensional spherical space, $S^{3}$, and of a charge-dipole potential constructed from the Green function to the $S^{3}$ Laplacian. The dipole potential emerged in view of the fact that $S^{3}$ does not support single-charges without violation of the Gauss theorem and the superposition principle, thus providing a natural stage for the description of the general phenomenon of confined charge-neutral systems. However, in the original article we did not relate the charge-dipoles on $S^{3}$ to the color neutral mesons, and did not express the magnitude of the confining dipole potential in terms of the strong coupling $\alpha_{S}$ and the number of colors, $N_{c}$, the subject of the addendum. To the amount $S^{3}$ can be thought of as the unique closed space-like geodesic of a four-dimensional de Sitter space-time, $dS_{4}$, we hypothesized the space-like region outside the causal Einsteinian light cone (it describes virtual processes, among them interactions) as the $(1+4)$-dimensional subspace of the conformal $(2+4)$ space-time, foliated with $dS_{4}$ hyperboloids, and in this way assumed relevance of $dS_{4}$ special relativity for strong interaction processes. The potential designed in this way predicted meson spectra of conformal degeneracy patterns, and in accord with the experimental observations. We now extract the $\alpha_{s}$ values in the infrared from data on meson masses. The results obtained are compatible with the $\alpha_{s}$ estimates provided by other approaches