Yoshitada Harada

The characteristics of dorsal-root ganglia and sensory innervation of the hip in rats

Using a rat model the characteristics of the sensory neurones of the dorsal-root ganglia (DRG) innervating the hip were investigated by retrograde neurotransport and immunohistochemistry. Fluoro-Gold solution (FG) was injected into the left hip of ten rats. Seven days later the DRG from both sides between T12 and L6 were harvested. The number of FG-labelled calcitonin gene-related peptide-immunoreactive or isolectin B4-binding neurones were counted. The FG-labelled neurones were distributed throughout the left DRGs between T13 and L5, primarily at L2, L3, and L4. Few FG-labelled isolectin B4-binding neurones were present in the DRGs of either side between T13 and L5, but calcitonin gene-related peptide-immunoreactive neurones made up 30% of all FG-labelled neurones. Our findings may explain the referral of pain from the hip to the thigh or lower leg corresponding to the L2, L3 and L4 levels. Since most neurones are calcitonin gene-related peptide-immunoreactive peptide-containing neurones, they may have a more significant role in the perception of pain in the hip as peptidergic DRG neurones.

Differential effects of oxidised and non-oxidised polyethylene particles on human monocyte/macrophages in vitro

Sterilisation by gamma irradiation in the presence of air causes free radicals generated in polyethylene (PE) to react with oxygen, which could lead to loss of physical properties and reduction in fatigue strength. Tissue retrieved from failed total hip replacements often has large quantities of particulate PE and most particles associated with peri-implant osteolysis are oxidised. Consequently, an understanding of the cellular responses of oxidised PE particles may lead to clarification of the pathogenesis of osteolysis and aseptic loosening. We have used the agarose system to demonstrate the differential effects of oxidised and non-oxidised PE particles on the release of proinflammatory products such as interleukin-1beta (IL-1beta), IL-6, and tumour necrosis factor-alpha (TNF-alpha) from monocytes/macrophages (M/M). Oxidised PE particles were shown to stimulate human M/M to phagocytose and to release cytokines. Oxidation may alter the surface chemistry of the particles and enhance the response to specific membrane receptors on macrophages, such as scavenger-type receptors.

Differences in Innervation and Innervated Neurons between Hip and Inguinal Skin

Pain originating from the hip may be referred to the groin and anterior thigh. We investigated sensory dorsal root ganglion neurons innervating the hip and the inguinal skin in rats using retrograde neurotransport and immunohistochemistry. A retrograde neurotracer Fluoro-Gold™ was injected into the left hip or inguinal skin of rats. Seven days later, we harvested bilateral dorsal root ganglions and counted the number of Fluoro-Gold™-labeled neurons positive for calcitonin gene-related peptide, a marker of nerve growth factor-dependent neurons, or isolectin B4, a marker of glial cell line-derived neurotrophic factor-dependent neurons. In the hip group, Fluoro-Gold™-labeled neurons were distributed throughout the left dorsal root ganglions from T13 to L5, primarily at L1, L2, L3, and L4, and the percentage of calcitonin gene-related peptide-positive neurons was higher than that of isolectin B4-binding neurons. In the inguinal skin group, Fluoro-Gold™-labeled neurons were distributed throughout the left dorsal root ganglions from T13 to L3, primarily at L1, L2, and L3, and the percentage of isolectin B4-binding neurons was higher than that of calcitonin gene-related peptide-positive neurons. These data suggest the sensory innervation pattern and characteristics of the sensory nerve of the rat hip are different from those of inguinal skin.

The incidence of alcohol-associated osteonecrosis of the knee is lower than the incidence of steroid-associated osteonecrosis of the knee: an MRI study

OBJECTIVE The purpose of the study was to clarify the incidence of alcohol-associated osteonecrosis of the knee using MRI. METHODS A total of 131 patients (56 women and 75 men) with osteonecrosis of the femoral head were enrolled; 60 patients had a history of alcohol abuse and 71 had previously received steroids. All patients underwent MRI of the knee. The incidence of alcohol-associated osteonecrosis of the knee was compared with that of steroid-associated osteonecrosis of the knee. Predictive factors of alcohol- and steroid-associated osteonecrosis of the knee were also evaluated. RESULTS The incidence of alcohol-associated osteonecrosis of the knee was lower than that of steroid-associated osteonecrosis of the knee (18.3 vs 54.9%; P < 0.001, Fishers exact probability test). No significant difference in weekly alcohol consumption was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee. No significant difference in daily maximum steroid doses was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee. CONCLUSION The present study revealed that the incidence of alcohol-associated osteonecrosis of the knee is lower than that of steroid-associated osteonecrosis of the knee.

Density of GM3 with Normal Primary Structure Determines Mouse Melanoma Antigenicity; a New Concept of Tumor Antigen

We attempted to induce anti‐melanoma cytotoxic T cells (CTL) and suppressor T cells (Ts) inhibiting CTL generation by using liposomes carrying various densities of GM3 as tumor antigens. We found that liposomes carrying 6–16 mol% of GM3 with normal primary structure successfully generated anti‐melanoma CTL and suppressor T cells, while liposomes with GM3 outside this range had little or no such activity. Anti‐melanoma CTL induced by GM3(NeuGc)‐liposomes belonged to CD4‐/CD8‐double‐negative CD3+ CTL while GM3(NeuAc)‐liposomes induced two types of T cells, CD4+ T cells and double‐negative I‐J positive T cells which mediated inhibition of the induction of anti‐melanoma CTL responses. These cell types were tbe same as those induced by mitomycin C‐treated melanoma cells for CTL induction and soluble melanoma antigen for Ts generation. The results clearly demonstrate that even GM3 with normal primary structure can, at a certain density, generate melanoma antlgenicity.

Dorsal root ganglion neurons with dichotomizing axons projecting to the hip joint and the knee skin in rats: possible mechanism of referred knee pain in hip joint disease

BackgroundPatients who have hip joint diseases sometimes complain of knee pain as well as hip joint area pain. However, the precise sensory innervation pattern and correlation of the sensory nerves of the hip joint and knee are unknown. The purpose of this study was to investigate dorsal root ganglion (DRG) neurons with dichotomizing axons projecting to both the hip joint and the knee skin in rats using double fluorescent labeling techniques, and to examine characteristics of the DRG neurons with dichotomizing axons using immunohistochemical staining for inflammatory neuropeptides such as calcitonin gene-related peptide (CGRP).MethodsFor 20 rats, two kinds of neurotracers, Fluoro-Gold (FG) and 1,1′-dioctadecyl-3,3,3′,3′-tetramethyl-indocarbocyanine perchlorate (DiI), were used in the double-labeling study. FG was injected into the left hip joint, and DiI was applied to the left medial portion of knee skin. Ten days after application, bilateral DRGs were harvested and immunohistochemically stained for CGRP.ResultsDRG neurons double labeled with FG and DiI were observed only from L2 to L4 on the left side. Approximately 1.6% of all DRG neurons innervating the hip joints had other axons that extended to the medial portion of knee skin, and 35% of double-labeled neurons were CGRP positive.ConclusionsOur results showed that the double-labeled neurons had peripheral axons that dichotomized into both the hip joint and the knee skin. CGRP-positive neurons of these dichotomizing fibers may play some role in the manifestation of referred knee pain with hip joint pain.

Quantitative T2 mapping of femoral head cartilage in systemic lupus erythematosus patients with noncollapsed osteonecrosis of the femoral head associated with corticosteroid therapy

To evaluate articular cartilage degeneration with transverse relaxation time (T2) mapping in systemic lupus erythematosus (SLE) patients with noncollapsed and asymptomatic osteonecrosis of the femoral head associated with corticosteroids.

The pattern of distribution of PGP 9.5 and TNF-alpha immunoreactive sensory nerve fibers in the labrum and synovium of the human hip joint.

To date, there has been no report clarifying the existence of sensory nerve fibers as the origin of the hip joint pain of osteoarthritis. We examined the existence of sensory nerve fibers in osteoarthritis (OA), osteonecrosis of the femoral head (ONFH), and femoral neck fracture of the human hip joint. Ten labra of 10 human hip joints were harvested during a total hip arthroplasty. Each labrum was separated into 12 sections and we used three sections for analysis, which included 2 weight-bearing and 1 non-weight-bearing portion. Protein gene product 9.5 (PGP 9.5) immunoreactive sensory nerve fibers were found in the labrum and synovium harvested from the weight-bearing portion in the OA group. Some of these sensory nerve fibers were also positive for tumour necrosis factor alpha (TNF). The PGP 9.5 immunoreactive sensory nerve fibers existed in the labrum tissue and inflammatory TNF positive cells were observed in the hyperplastic synovium. On the other hand, we could not demonstrate PGP 9.5 or TNF immunoreactive sensory nerve fibers and cells in any of the ONFH group or the non-weight-bearing portion in the OA group. These data suggest that the pain of ONFH and OA of the hip joint have different pathogenetic mechanisms and that the invasion of sensory nerve fibers containing TNF may be involved in the pathogenesis of pain in the human hip joint affected by OA.

Hip arthrography under general anesthesia to refine the definition of hinge abduction in Legg-Calvé-Perthes disease.

Background: Hinge abduction is widely accepted as a poor prognostic factor in Legg-Calvé-Perthes disease (LCPD), whereas the exact definition of hinge abduction remains ill defined. The purpose of this diagnostic study was to refine the definition of hinge abduction in LCPD using conventional hip arthrography under general anesthesia. Methods: Among 350 hips in 332 LCPD patients, we reviewed 92 hips in 90 patients (75 boys and 15 girls) who consecutively underwent arthrography under general anesthesia because of an expected poor prognosis. The mean age at LCPD onset was 8.2 years (range, 4-13 years). With respect to lateral pillar classification, 25 hips were classified as group B, 27 as B/C border, and 40 as C. Subluxation (≥3-mm difference from unaffected side) was present in 81 (88%) of the 92 hips. The modified Waldenström classification was used for evaluating the radiographic stage of disease at the time of arthrography: 80 hips were classified as fragmentation stage and 12 as reossification stage. Hinge abduction was defined as an increased subluxation index in maximum abduction and/or a positive impingement sign. Results: Under this definition, 11% (10 hips) of the study group had hinge abduction. The range of abduction under general anesthesia (40 degrees) was significantly greater than in the awake condition (24 degrees, P < 0.0001). Conclusions: The subluxation index and the impingement sign proved to be reliable indicators for diagnosing hinge abduction. Conventional arthrography remains useful. General anesthesia provided an analgesic effect and muscle relaxation. Level of Evidence: Level II (diagnostic study, development of diagnostic criteria on the basis of consecutive patients).

Induction of Mouse Anti‐melanoma Cytotoxic and Suppressor T Cells in vitro by an Artificial Antigen, GM3‐lactone

We investigated the ability of GM3‐lactone liposomes to induce anti‐melanoma T cell responses in mice. GM3‐lactone liposomes, like murine B16 melanoma cells, induced anti‐melanoma cytotoxic T cells (CTL) and also suppressor T cells (Ts). A small dose of GM3‐lactone (0.0003 μg/ml) was enough to generate CTL in the in vitro primary response, whereas relatively large amounts of the antigen (0.03–0.3 μg/ml) were required for anti‐melanoma Ts induction. As the epitope for anti‐melanoma Ts is NeuAc but not NeuGc residue on GM3, and anti‐melanoma CTL are effectively induced by either GM3(NeuAc) or GM3(NeuGc)‐lactone liposomes, GM3(NeuGc)‐lactone or GM3(NeuGc) liposomes have potent activity as an artificial melanoma antigen to induce anti‐melanoma CTL in vitro.