A cellular implantation system using an injectable ultra-purified alginate gel for repair of osteochondral defects in a rabbit model

We developed a novel cellular implantation system using an in situ forming ultra-purified alginate gel with quite low endotoxity. The aims of this study were to determine the superiority of chondrogenic potential of bone marrow stromal cells (BMSCs) cultured in the purified alginate gel compared with a commercial grade gel, and to assess reparative tissues treated with BMSCs implanted using the developed system into cartilage defects in rabbit knees. The effects of each alginate gel on cellular proliferation and chondrogenesis of rabbit BMSCs were determined by in vitro assessments. Using our purified alginate gel, a novel vehicle system for injecting BMSCs into osteochondral defects without periosteal patch was successfully established in this animal models. The in vitro analyses demonstrated that the purification of alginate significantly enhanced the cellular proliferation and chondrogenic differentiation of BMSCs. The in vivo assessments suggested that the implantation of BMSCs with the developed system using the purified alginate gel histologically and mechanically improved the reparative tissue of osteochondral defects. This system using the purified alginate gel shows the clinical potential for arthroscopically injectable implantation of BMSCs for the treatment of cartilaginous lesions.

Tunnel location in transparent 3-dimensional CT in anatomic double-bundle anterior cruciate ligament reconstruction with the trans-tibial tunnel technique

It is difficult to precisely identify the locations of tunnels after double-bundle anterior cruciate ligament (ACL) reconstruction postoperatively. Using our novel transparent 3-dimensional computed tomography (T-3DCT), we evaluated intra-articular outlet locations and the angles of the anteromedial (AM) and posterolateral (PL) tunnels after anatomic double-bundle ACL reconstruction using the trans-tibial technique. A prospective study was performed with 123 consecutive patients. Tunnel outlet locations were identified on T-3DCT images showing the true lateral view of the femur and indicated by our originally defined X, Y coordinates. We also determined the angles between the tunnel axis and a joint surface line in the coronal plane, the long axis of the femur in the sagittal plane, and the posterior condyle line in the axial plane of both the femur and the tibia. The mean X, Y coordinates of the AM and PL tunnel outlets were 21, 43% and 0, 33%, respectively. In the coronal, sagittal, and axial planes, the mean AM femoral tunnel angles were 63 degrees, 48 degrees, and 55 degrees, respectively; the mean AM tibial tunnel angles in the tibia were 63 degrees, 49 degrees, and 71 degrees, respectively; the mean PL femoral tunnel angles were 38 degrees, 58 degrees, and 43 degrees, respectively; and the mean PL tibial tunnel angles were 46 degrees, 53 degrees, and 45 degrees, respectively. The AM and PL tunnel outlets and angles could be detailed precisely in three dimensions by using T-3DCT. This imaging technique may be useful to confirm surgical techniques and to improve clinical outcomes.

Liquid-gated interface superconductivity on an atomically flat film

Liquid/solid interfaces are attracting growing interest not only for applications in catalytic activities and energy storage, but also for their new electronic functions in electric double-layer transistors (EDLTs) exemplified by high-performance organic electronics, field-induced electronic phase transitions, as well as superconductivity in SrTiO(3) (ref. 12). Broadening EDLTs to induce superconductivity within other materials is highly demanded for enriching the materials science of superconductors. However, it is severely hampered by inadequate choice of materials and processing techniques. Here we introduce an easy method using ionic liquids as gate dielectrics, mechanical micro-cleavage techniques for surface preparation, and report the observation of field-induced superconductivity showing a transition temperature T(c)=15.2 K on an atomically flat film of layered nitride compound, ZrNCl. The present result reveals that the EDLT is an extremely versatile tool to induce electronic phase transitions by electrostatic charge accumulation and provides new routes in the search for superconductors beyond those synthesized by traditional chemical methods.

Induction of primary systemic therapy by weekly paclitaxel: Predictive value of hormone receptors, HER-2, topoisomerase II- alpha, and other biological markers in relation to pathological complete response

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Background: Randomized phase II study of epirubicin(E) plus cyclophosphamide (C) vs. weekly paclitaxel (P) as primary systemic therapy (PST) in stage II and III breast cancer(BC) have shown that there was no significant difference in the pathological complete response (pCR) rate between the EC and P groups (#568 ASCO 2008). The aim of this study is to evaluate the predictive value of hormone receptors, HER2, topoisomerase IIα(TOP II) and other biological markers in the EC and P groups as PST. Methods: Tissue samples were obtained before PST from pts who were randomized to either Arm A (EC: E 75 mg/m2 and C 600 mg/m2 every 3 W for 4 cycles) or Arm B (weekly P: P 80 mg/m2 weekly for 12 w). Pts received PST for 12 w, then underwent surgery. All pts received a crossover regimen as adjuvant chemotherapy.The pretreatment expression of estrogen receptor (ER), progesterone receptor(PgR), HER2, P53, Ki67, P21 and CD31 were analized by immunohistochemical staining. The status of TOP II gene was evaluated by FISH. Results: One-hundred- sixty pts (Arm A: n=82, Arm B: n=78 ) were estimable. The pCR rates were 13.4% in Arm A and 17.9% in Arm B(p=0.43). In both arms, pCR rate was significantly higher for pts whose tumors did not express ER nor PgR(ER/PgR-) compared with the receptor positive(ER/PgR+) pts. Pts with HER2 positive tumors tend to have higher pCR rate in Arm B compared with Arm A (32.2% vs. 12.5%;p=0.11). The pCR rate for pts with HER2 negative BC were not different in both Arms(A:14.0% vs. B:8.5%). Pts with triple negative (TN) (ER/PgR, HER2-) BC achieved almost same pCR in both Arms (A:25.0% vs. B:23.1%). However, the pCR rate for pts with nonTN BC was significantly higher in ArmB compared to Arm A (16.9% vs. 8.6%, p<0.001). The deletion and amplification of TOP II gene were not predictive of higher pCR rate to ArmA than to Arm B. The pretreatment expression of P53, Ki67, P21 and CD31 was unlikely to predict the higher response of any Arm. Conclusions: Althogh valuable predictive factor of pCR were not detected between EC and weekly P group, the efficacy of weekly P therapy as PST were equal to EC therapy regardless of HR,HER2 and TOP II gene status. Therefore, induction of PST by weekly P therapy seems to be promising.

No significant financial relationships to disclose.

Development of mature cartilage constructs using novel three-dimensional porous scaffolds for enhanced repair of osteochondral defects

In this study, we successfully developed two types of volume-reduced three-dimensional scaffolds, including cushion- and cylinder-shape scaffolds, fabricated from chitosan-based hyaluronic acid hybrid polymer fibers. Using these scaffolds combined with a bioreactor system, we regenerated histologically and mechanically mature cartilage constructs. The final goal of this study was to clarify the ability of this engineered cartilage construct to induce cartilage repair in osteochondral defects. The mature cartilage constructs regenerated with two types of scaffolds were implanted into 5-mm diameter osteochondral defects in the patellar groove of rabbits. At 12 weeks after implantation, the reparative tissues consisted of hyaline-like cartilage with evidence of stable fusion to adjacent native cartilage and normal reconstitution of subchondral bone. The histological score of these tissues significantly outranked the value of untreated tissue. Biomechanically, compression modulus of reparative tissue at 12 weeks postoperatively was comparative to that of normal articular cartilage. Our results indicate that the implantation of constructs with mature cartilage have potential as a better approach for joint resurfacing.

Thermal conductivity evidence for a dx2-y2 pairing symmetry in the heavy-fermion CeIrIn5 superconductor

The phase diagram of the quasi-2D Ce(Ir,Rh)In5 system contains two distinct superconducting domes. By the thermal transport measurements in rotating magnetic fields H, we pinned down the superconducting gap structure of CeIrIn5 in the second dome, located distant from the first dome in proximity to an antiferromagnetic quantum critical point. Clear fourfold oscillation was observed when H is rotated within the ab plane, while no oscillation was observed within the bc plane. In sharp contrast to previous reports, our results are most consistent with dx2-y2 symmetry, implying that the superconductivity in the second phase is also mediated by antiferromagnetic spin fluctuations.

Flux line lattice melting and the formation of a coherent quasiparticle Bloch state in the ultraclean URu2Si2 superconductor

We find that in the ultraclean heavy-fermion superconductor URu(2)Si(2) (T_{c0}=1.45 K) a distinct flux line lattice melting transition with outstanding characters occurs well below the mean-field upper critical fields. We show that a very small number of carriers with heavy mass in this system results in exceptionally large thermal fluctuations even at sub-Kelvin temperatures, which are witnessed by a sizable region of the flux line liquid phase. The uniqueness is further highlighted by an enhancement of the quasiparticle mean free path below the melting transition, implying a possible formation of a quasiparticle Bloch state in the periodic flux line lattice.

Exotic superconducting properties in the electron-hole-compensated heavy-fermion "Semimetal" URu2Si2

We show that the charge and thermal transport measurements on ultraclean crystals of URu2Si2 reveal a number of unprecedented superconducting properties. The uniqueness is best highlighted by the peculiar field dependence of thermal conductivity including the first-order transition at Hc2 with a reduction of entropy flow. This is a consequence of multiband superconductivity with compensated electronic structure in the hidden order state of this system. We provide strong evidence for a new type of unconventional superconductivity with two distinct gaps having different nodal topology.

Effect of pore size on in vitro cartilage formation using chitosan-based hyaluronic acid hybrid polymer fibers

In this study, we successfully developed three-dimensional scaffolds fabricated from the chitosan-based hyaluronic acid hybrid polymer fibers, which can control the porous structure. To determine the adequate pore size for enhancing the chondrogenesis of cultured cells, we compared the behaviors of rabbit chondrocytes in scaffolds comprising different pore sizes (100, 200, and 400 microm pore size). Regarding the cell proliferation, there was no significant difference among the three groups. On the other hand, glycosaminoglycan contents in the 400 microm group significantly increased during the culture period, compared with those in the other groups. The ratio of type II to type I collagen mRNA level was also significantly higher in the 400 microm group than in the other groups. These results indicate that our scaffold with 400 microm pore size significantly enhances the extracellular matrix synthesis by chondrocytes. Additionally, the current scaffolds showed high mechanical properties, compared with liquid and gel materials. The data derived from this study suggest great promise for the future of a novel fabricated material with relatively large pore size as a scaffold for cartilage regeneration. The biological and mechanical advantages presented here will make it possible to apply our scaffold to relatively wide cartilaginous lesions.

effects of rattling phonons on the dynamics of quasiparticle excitation in the beta-pyrochlore KOs(2)O(6) Superconductor

Microwave penetration depth lambda and surface resistance at 27 GHz are measured in high quality crystals of KOs(2)O(6). Firm evidence for fully gapped superconductivity is provided from lambda(T). Below the second transition at T(p) approximately 8 K, the superfluid density shows a steplike change with a suppression of effective critical temperature T(c). Concurrently, the extracted quasiparticle scattering time shows a steep enhancement, indicating a strong coupling between the anomalous rattling motion of K ions and quasiparticles. The results imply that the rattling phonons help to enhance superconductivity, and that K sites freeze to an ordered state with long quasiparticle mean free path below T(p).

Clonotypic analysis of T cell reconstitution after haematopoietic stem cell transplantation (HSCT) in patients with severe combined immunodeficiency

Haematopoietic stem cell transplantation (HSCT) is performed for treatment of a broad spectrum of illnesses. Reconstitution of an intact immune system is crucial after transplantation to avoid infectious complications, and above all, the establishment of T cell receptor (TCR) diversity is the most important goal in the procedure. Until recently, little has been known of the mechanism of T cell reconstitution in the very early period after HSCT. In this study, we analysed TCR repertoires sequentially in four patients with severe combined immunodeficiency (SCID) before and after HSCT. In all patients, the TCR repertoires were extremely abnormal before HSCT, whereas after transplantation there was progressive improvement in TCR diversity, based on analysis of the TCR Vbeta repertoire and CDR3 size distributions. Somewhat unexpectedly, there was a significant but transient expansion of TCR diversity 1 month after transplantation in all cases. Clonotypic analysis of TCRs performed in one case showed that many T cell clones shared identical CDR3 sequences at 1 month and that the shared fraction decreased progressively. These results indicate that early expansion of TCR diversity may reflect transient expansion of pre-existing mature T cells from the donor blood, independent of de novo T cell maturation through the thymus.

Thermal conductivity of the pyrochlore superconductor KOs2O6: strong electron correlations and fully gapped superconductivity

To elucidate the nature of the superconducting ground state of the geometrically frustrated pyrochlore KOs2O6 (Tc=9.6 K), the thermal conductivity was measured down to low temperatures (approximately Tc/100). We found that the quasiparticle mean free path is strikingly enhanced below a transition at Tp=7.8 K, indicating enormous electron inelastic scattering in the normal state. In magnetic fields, the conduction at T-->0 K is nearly constant up to approximately 0.4Hc2, in contrast with the rapid growth expected for superconductors with an anisotropic gap. This unambiguously indicates a fully gapped superconductivity, in contrast with previous studies. These results highlight that KOs2O6 is unique among superconductors with strong electron correlations.