We have previously shown that administration of platelet-rich plasma-impregnated gelatin hydrogel microspheres (PRP-GHMs) into a degenerated intervertebral disc (IVD) markedly suppresses progression of IVD degeneration. In the current study, we characterized the in vivo effects of PRP-GHM treatment in a degenerated IVD model in rabbit. On magnetic resonance images, the IVD height was significantly greater after treatment with PRP-GHMs compared with phosphate-buffered saline-impregnated GHMs, PRP without GHMs, and needle puncture only. Water content was also preserved in PRP-GHM-treated IVDs. Consistent with this observation, the mRNA expression of proteoglycan core protein and type II collagen was significantly higher after PRP-GHM treatment compared with other treatment groups. No proliferating cells were found in the nucleus pulposus and inner annulus fibrosus in any groups, but the number of apoptotic cells in the nucleus pulposus after PRP-GHM treatment was significantly lower than that after other treatments. These results provide an improved understanding of the therapeutic effects of PRP-GHM treatment of degenerated IVDs.

The method used in this study might be applied to clinical analysis of foot diseases such as the staging of flatfoot and to biomechanical analysis to evaluate the effects of foot surgery in the future.

PurposeIt has previously been found that valgus hindfoot alignment (HFA) improves 3 weeks following total knee arthroplasty (TKA) for varus knee osteoarthritis (OA). In the present study, HFA was evaluated prior to TKA, as well as 3 weeks and 1 year following TKA. Using these multiple evaluations, the chronological effects of TKA on HFA were investigated.MethodsThe study included 71 patients (73 legs) who underwent TKA for varus knee OA. Radiograph examinations of the entire limb and hindfoot were performed in the standing position prior to TKA, as well as 3 weeks and 1 year following TKA. The varus–valgus angle was used as an indicator of HFA in the coronal plane. Patients were divided into two groups according to the preoperative varus–valgus angle: a hindfoot varus group (varus–valgus angle <76°) and a hindfoot valgus group (varus–valgus angle ≥76°). The changes in the varus–valgus angle were evaluated and compared in both groups.ResultsIn the hindfoot valgus group, the mean ± standard deviation varus–valgus angle significantly declined from 80.5 ± 3.1° prior to TKA to 78.6 ± 3.7° 3 weeks following TKA and 77.1 ± 2.7° 1 year following TKA. However, in the hindfoot varus group, the mean varus–valgus angle prior to TKA (72.7 ± 2.6°) did not differ significantly from the mean varus–valgus angles 3 weeks (72.3 ± 3.3°) or 1 year (73.5 ± 3.0°) following TKA.ConclusionsHFA improved chronologically in legs with hindfoot valgus as a result of the alignment compensation ability of the hindfoot following TKA. However, no improvement was noted in legs with hindfoot varus because the alignment compensation ability of the hindfoot had been lost. The patients with hindfoot varus should be attended for ankle pain in the outpatient clinic after TKA.Level of evidenceIII.

The one-dimensional 2 H double quantum filtered (DQF) spectroscopic imaging technique was used to study the orientation of collagen fibers in articular cartilage. The method detects only water molecules in anisotropic environments, which in cartilage is caused by their interaction with the collagen fibers. A large quadrupolar splitting was observed in the calcified zone and a smaller splitting in the radial zone. In the transitional zone the splitting was not resolved and a small splitting was again detected in the superficial zone. From measurements performed at two orientations of the plug relative to the magnetic field it was deduced that in the calcified and radial zones the fibers are oriented perpendicular to the bone, bending at the transitional zone and flattening at the superficial zone. The effect of load applied to the cartilage-bone plug was monitored by the same technique. At low loads there is a small decrease in the quadrupolar splitting in the calcified zone, a marked decrease in the radial zone, and an increase of the splitting accompanied by a thickening of the superficial zone. Under high loads, while the thickening and the splitting of the superficial zone further increase, the splitting in the radial and calcified zones completely Key words: DQF MRI; articular cartilage; compression; collagen orientationArticular cartilage is a dense connective tissue that coats the ends of bones in their joints. It is mainly composed of water (ϳ75%) and of a solid matrix of collagen fibrils (ϳ15%) and proteoglycans (PG) (ϳ10%). The fibrous, triple helix collagen molecules define the tissue's shape and provide its tensile strength. The PG are composed of a central protein core with many glycosaminoglycan (GAG) sulfated sidechains. These are highly negatively charged and thus attract high concentrations of positive ions and water molecules. Scanning electron microscopy (SEM) has shown that the collagen fibers rise vertically from the bone through the radial zone, then bend and flatten, forming the superficial tangential zone (1-3). This structure, together with the large osmotic pressure in the tissue, is responsible for the remarkable compressive strength of the tissue.In conventional MR images, articular cartilage has a laminated appearance (4 -14). The number of laminae, their relative thickness and intensity, vary from study to study and from sample to sample and are strongly dependent on the orientation of the tissue in the magnetic field. In collagen-containing tissues, it has been shown that the transverse relaxation rate is dominated by the residual dipolar interaction (6,8,15), which is a result of the anisotropic motion of the water molecules. Thus, T 2 depends on the orientation of the collagen fibers with respect to the magnetic field.The main function of cartilage is to withstand pressure. Direct visualization of the orientation of the collagen fibers in articular cartilage at rest and under applied load is obtained by SEM (2,3). MRI investigations of articular cartilage under various degrees of...

Background The acquisition of flatfoot by an adult is thought to primarily be caused by posterior tibial tendon dysfunction, although some other causes, such as congenital flexible flatfoot or an accessory navicular, may also be responsible. The objective of this study was to evaluate the bone rotation of each joint in the medial longitudinal arch (MLA) and compare the response in healthy feet with that in flat feet by analyzing the reconstructive three-dimensional (3D) CT image data during weightbearing. Methods CT scans of 20 healthy feet and 24 feet with flatfoot deformity were taken in non-load condition followed by full-body weightbearing condition. Images of the tibia and MLA bones (first metatarsal bone, cuneiforms, navicular, talus, and calcaneus) were reconstructed into 3D models. The volume merge method in three planes was used to calculate the bone-to-bone relative rotations. Findings Under loading conditions, the flatfoot dorsiflexed more in the first tarsometatarsal joint, and everted more in the talonavicular and talocalcaneal joints compared with the healthy foot. The total relative rotation was larger in the flatfoot compared with the healthy foot only in the first tarsometatarsal joint. Interpretation Supporting the MLA in the sagittal direction and the subtalar joint in the coronal direction may be useful for treating flatfoot deformity. The first tarsometatarsal joint may play an important role in diagnosing or treating flatfoot deformity.

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The circadian clock regulates behavioural and physiological processes in a 24-h cycle. The nuclear receptors REV-ERBα and REV-ERBβ are involved in the cell-autonomous circadian transcriptional/translational feedback loops as transcriptional repressors. A number of studies have also demonstrated a pivotal role of REV-ERBs in regulation of metabolic, neuronal, and inflammatory functions including bile acid metabolism, lipid metabolism, and production of inflammatory cytokines. Given the multifunctional role of REV-ERBs, it is important to elucidate the mechanism through which REV-ERBs exert their functions. To this end, we established a Rev-erbα / Rev-erbβ double-knockout mouse embryonic stem (ES) cell model and analyzed the circadian clock and clock-controlled output gene expressions. A comprehensive mRNA-seq analysis revealed that the double knockout of both Rev-erbα and Rev-erbβ does not abrogate expression rhythms of E-box-regulated core clock genes but drastically changes a diverse set of other rhythmically-expressed output genes. Of note, REV-ERBα/ β deficiency does not compromise circadian expression rhythms of PER2, while REV-ERB target genes, Bmal1 and Npas2 , are significantly upregulated. This study highlight the relevance of REV-ERBs as pivotal output mediators of the mammalian circadian clock.

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