Shoichi Kokubun

Spinal dumbbell tumors: an analysis of a series of 118 cases

OBJECT The authors analyzed a series of 118 cases of spinal dumbbell tumors to elucidate the feature of the tumors. METHODS Of 674 cases of spinal cord tumors, the incidence of dumbbell tumors was studied. The tumors were analyzed, and the authors focus on the distribution of age and sex, the pathological diagnoses, their locations, Eden classification, and the surgical methods used. RESULTS The incidence of dumbbell tumors was 18%. The mean patient age was 43 years, which was younger than that for all spinal cord tumors (mean 50 years). There were 11 patients younger than 10 years of age. The rate of dumbbell tumors in the cervical spine was significantly higher than that of all spinal cord tumors. Fifteen (18%) of the 81 schwannomas were observed in the C-2 nerve root, thus having a higher incidence than those in the other nerve roots. In 99 cases (84%), the tumors were removed through a hemilaminectomy with or without a facetectomy and posterior fusion. Of 118 cases, 69% of the tumors were schwannomas, and malignant tumors were found in 10 cases (8.5%). Seven (64%) of 11 patients younger than 10 years of age had malignant tumors. Three patients older than 10 years of age had malignant tumors, thus accounting for 2.8% of the 107 older patients. CONCLUSIONS The incidence of dumbbell tumors was 18%, and they are not uncommon. Malignant dumbbell tumors were more common in children younger than 10 years of age than in older patients.

APOPTOSIS AND PROLIFERATION OF GROWTH PLATE CHONDROCYTES IN RABBITS

The growth plates of the femoral head of Japanese white rabbits aged 5, 10, 15 and 20 weeks were stained for apoptotic and proliferating chondrocytes using the TUNEL and PCNA antibody staining techniques. Both TUNEL- and PCNA-positive chondrocytes were detected in all of the specimens. The positive ratios of both stainings were calculated for the whole plate and for the resting, proliferating and hypertrophic zones. The highest ratios in both stainings occurred in the hypertrophic zone in all age groups. With growth, the TUNEL-positive ratio increased whereas the proliferating ratio decreased. We suggest that the increase in chondrocytic death by apoptosis and the decrease in cell proliferation potential led to closure of the growth plate.

Myofibers Express IL-6 After Eccentric Exercise

Background Interleukin (IL)-6 is locally produced in skeletal muscles and shows a remarkable increase in plasma after eccentric exercises. Objective To elucidate the cell types in the muscles responsible for IL-6 production after eccentric exercises. Study Design Controlled laboratory study. Methods An eccentric contraction model was made using electrical stimulation. The authors investigated the muscle damage and regeneration processes after eccentric exercises histologically, and the cell types expressing IL-6 and its subcellular compartimentalization with time immunohistochemically after eccentric exercises. Results Swollen myofibers were detected from 8 hours to 3 days after exercises. Disrupted myofibers were detected from 24 hours to 7 days, with a peak of 3 days. IL-6 was detected only in the cytoplasm of myofibers until 12 hours; thereafter, it was found in the inflammatory cells and proliferating satellite cells as well. The swollen myofibers were negatively stained for IL-6. The positive ratios of IL-6 in myofibers immediately increased after exercises, peaked in 12 hours, and then decreased. Conclusions After eccentric exercises, IL-6 expression increased in myofibers preceding the disruption of myofibers. IL-6 might be closely related to muscle damage caused by strenuous exercises.

Changes with age in proteoglycan synthesis in cells cultured in vitro from the inner and outer rabbit annulus fibrosus. Responses to interleukin-1 and interleukin-1 receptor antagonist protein.

Study Design. Proteoglycan synthesis was examined in cells isolated from the inner and outer annulus fibrosus of young and old rabbits. Their responses to interleukin-1&agr; and interleukin-1 receptor antagonist protein were investigated. Objectives. To evaluate the age-related changes and the anatomically related differences in the function of intervertebral disc cells. Summary of Background Data. Proteoglycan content in the human intervertebral disc decreases with age. Age-related changes in intervertebral disc cell function, however, have not been fully investigated. Methods. Japanese white rabbits aged 2 months (young group) and 3 years (old group) were used. The inner and outer layer of the annulus fibrosus were separated. The proteoglycan synthesis and release were measured in cells cultured with or without human recombinant interleukin-1&agr; and interleukin-1 receptor antagonist protein. Results. The proteoglycan synthesis significantly decreased and the release rate significantly increased in the old rabbits, compared with the young ones. In the inner annulus, the inhibition of proteoglycan synthesis due to interleukin-1&agr; was greater in the old rabbits than in the young ones. In the old rabbits, interleukin-1–induced inhibition was more pronounced in the inner annulus than in the outer annulus. Interleukin-1 receptor antagonist protein suppressed inhibition of proteoglycan synthesis by interleukin-1&agr; in the two layers in both age groups. Conclusions. Both the decline in proteoglycan synthesis and the increased cell sensitivity to interleukin-1&agr; with age may contribute to the degradation of discs. The increase in cell response to interleukin-1&agr; in the inner annulus of rabbits may explain why the inner annulus and nucleus pulposus degrade earlier than the outer annulus in human discs. Interleukin-1 receptor antagonist protein could be useful in inhibiting the degradation of the disc.

Results of surgical treatment for thoracic myelopathy: minimum 2-year follow-up study in 132 patients

OBJECT Thoracic myelopathy is uncommon compared with cervical myelopathy. In this study, data obtained in patients with thoracic myelopathy caused by degenerative processes of the spine were retrospectively analyzed to clarify the surgical outcomes and to examine the various factors affecting the postoperative improvement. METHODS Between 1988 and 2002, 132 patients with thoracic myelopathy underwent surgery and a minimum 2-year observation period. Clinical data were collected from medical and operative records, and sagittal alignment of the spine was measured on radiographs. The patients were evaluated pre- and postoperatively using the modified Japanese Orthopaedic Association (JOA) scale (maximum score 11). The relationships among various factors affecting the preoperative severity of myelopathy and postoperative improvement were also examined. RESULTS The population consisted of 97 men (mean age at surgery was 58 years) and 35 women (mean age at surgery 62 years). Myelopathy was caused by ossification of the ligamentum flavum (OLF) in 73 patients, ossification of the posterior longitudinal ligament (OPLL) in 21, combined OLF-OPLL in 10, intervertebral disc herniation (IDH) in 15, posterior bone spur in 11, and OLF with IDH or posterior bone spur in one patient each. The surgical outcome was relatively good: a mean preoperative JOA score of 5.3 improved to a mean score of 7.8 at the last follow-up, 50 months on average after surgery. Thoracic myelopathy caused by OPLL, however, was associated with lower postoperative scores and recovery rates. In more than half of the patients the authors documented an increase of kyphosis of less than 2 degrees. CONCLUSIONS Patients with a shorter preoperative duration of symptoms and milder myelopathy experienced significantly better postoperative neurological conditions, which indicated that those who present earlier with fewer disabilities should be recommended to undergo surgery in time, although the surgical treatment for OPLL still involves many problems.

Crowned Dens Syndrome

BACKGROUND Patients with crowned dens syndrome typically present with severe neck pain and have calcium deposits around the odontoid process of the axis on radiographs. To our knowledge, the cases of only thirty-five patients have been reported in the English-language literature and the clinical features remain unclear. The purposes of this study were to examine the clinical features of crowned dens syndrome, determine treatment outcomes, and propose diagnostic criteria. METHODS Forty patients with severe neck pain had calcium deposition around the odontoid process on computed tomography scans, and they were thus diagnosed as having crowned dens syndrome. Data were collected in relation to these patients, including the date of onset of neck pain, the presence of inflammatory indicators (increased body temperature, C-reactive protein levels, and white blood-cell count), and treatment outcomes. RESULTS The male-to-female ratio was 0.6, and two-thirds of the patients were more than seventy years of age. All patients had markedly restricted neck motion, particularly in rotation, and all had one or more positive inflammatory indicators. Calcium deposition was detected in all areas around the odontoid process, but chiefly behind the process. Pain was typically relieved by nonsteroidal anti-inflammatory drugs, prednisolone, or both. A combination of both appeared to be the most effective. CONCLUSIONS We believe that crowned dens syndrome is more common than previously recognized, especially in elderly patients. It is diagnosed on the basis of acute and severe neck pain; marked restriction of neck motion, particularly in rotation; the presence of inflammatory indicators, such as an elevated C-reactive protein level; calcium deposition around the odontoid process detected by computed tomography; no history of trauma; and the exclusion of other inflammatory diseases and tumors. Prednisolone and nonsteroidal anti-inflammatory drugs in combination are the recommended treatment for symptom relief.

Cervical myelopathy in the Japanese.

Surgeries (1155 cases) for cervical myelopathy in a northeastern prefecture (population, 2.26 million) and surrounding areas were reviewed. The annual operation rate per 100,000 residents in the prefecture was 5.7. Most of the patients were in their sixth or seventh decade of life (27% each), but the annual operation rate per 100,000 people of each decade of age was the highest in the eighth decade (16.5 per 100,000 people). At the largest spine center, 41% of 306 patients had a preoperative disease period of more than 1 year, and 65% had severe disabilities. Anterior and posterior decompression were about equally chosen. The former, mainly indicated for younger adults and single- or 2-level spinal cord compression, led to better functional improvement. Laminoplasty (93%) was predominant over laminectomy. Forty percent of the patients had developmental stenosis; 48%, dynamic stenosis; 27%, disc herniation; 11%, segmental ossification of the posterior longitudinal ligament; 9%, continuous ossification of the posterior longitudinal ligament; 8%, posterior spur; and 4%, calcification of the ligamentum flavum. Fifty-two percent had more than 1 of these spinal diseases.

Vascular supply to slipped capital femoral epiphysis.

The etiology of avascular necrosis associated with slipped capital femoral epiphysis has not been well understood. The aims of this study were to clarify the blood supply to the slipped epiphysis and to examine whether this vascular supply is damaged before the reduction. Twelve patients (12 hips) underwent selective angiography of the medial circumflex femoral artery. There were seven stable slips and five unstable slips. All patients with slips underwent angiography before reduction, and one patient with an unstable slip underwent angiography both before and after reduction. The superior retinacular artery (SRA) was filled in all stable slips. This result was in accordance with the previous report that stable slips result in low rates of avascular necrosis. Of five unstable slips, the SRA was stained in two and was not filled in three. In one slip examined both before and after the manipulative reduction, the SRA was not seen before it but was well stained after it. These results have suggested that in some unstable slips the vascular injury occurs at the time of injury, before reduction, and that the reduction dose not necessarily contribute to the risk of avascular necrosis after slipped capital femoral epiphysis.

Sex steroid receptors in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a disease characterized primarily by chronic inflammatory synovitis and is well-known to be associated with significant sex differences in its prevalence and clinical features. Sex steroids have been proposed to be involved in the pathogenesis of RA, but details pertaining to the expression of sex steroid receptors in RA synovial tissue have yet to be fully characterized. In the present study, we examined oestrogen receptor (ER) alpha, ERbeta, progesterone receptor (PR) and androgen receptor (AR) mRNA expression using real-time reverse transcriptase-PCR (RT-PCR) in eight female RA synovial tissues and six female synovial tissues without inflammation, and determined immunolocalization of ERalpha, ERbeta, PR-A, PR-B and AR using immunohistochemistry in synovial tissues obtained from 22 RA patients. Real-time RT-PCR analysis demonstrated the expression of ER, PR and AR mRNAs in both RA and non-inflamed synovial tissues. Relative abundance of ER mRNAs was significantly higher in RA synovial tissue than non-inflamed synovial tissue (P<0.05). In addition, the relative ERalpha/ERbeta mRNA expression ratio was significantly lower in RA than non-inflamed synovial tissue (RA, 2.34 +/- 1.60; and non-inflamed, 20.7 +/- 19.1; P<0.05). There were no significant differences in relative abundance of PR mRNA. Relative abundance of AR mRNA was significantly lower in RA (P<0.05). Immunoreactivity for ERalpha, ERbeta, PR-B and AR was detected in the lining cells, inflammatory cells and fibroblasts in all the patients examined. The labelling indices for ERbeta and PR-B were more abundant in both lining cells (ERbeta, 54.2 +/- 12.2%; PR-B, 73.6 +/- 18.9%) and inflammatory cells (ERbeta, 74.6 +/- 16.2%; PR-B, 75.9 +/- 16.1%) than in fibroblasts (ERbeta, 36.5 +/- 15.6%; PR-B, 49.4 +/- 18.0%). Labelling indices for ERalpha and AR were significantly higher in lining cells (ERalpha, 14.4 +/- 8.6%; AR, 31.2 +/- 11.3%) and fibroblasts (ERalpha, 12.1 +/- 7.5%; AR, 20.1 +/- 9.6%) than those in inflammatory cells (ERalpha, 5.7 +/- 3.3%; AR, 9.2 +/- 4.4%). There were significant differences (P<0.05) in the labelling indices for ERalpha, ERbeta and PR-B between men and women under 50 years of age in fibroblasts of RA synovial tissues. These results indicate that sex steroid receptors are present in RA and non-inflamed synovial tissues, including inflammatory cells in RA, and suggest that sex steroids may play important roles in the regulation of inflammation of RA synovial tissue.

Improved Quantification of DNA Methylation Using Methylation-Sensitive Restriction Enzymes and Real-Time PCR

Heterogeneity of cells with respect to the DNA methylation status at a specific CpG site is a problem when assessing methylation status. We have developed a simple two-step method for the quantification of the percent of cells that display methylation at a specific CpG site in the promoter of a specific gene. The first step is overnight digestion of genomic DNA (optimal conc. 20ng/5μl) with a relevant methylation-sensitive restriction enzyme (optimal 2 units). This is followed by real time PCR, using the SYBR® Green method, with primers that bracket the site cleaved by the enzyme. By including fully methylated and fully non-methylated DNA in each PCR plate, the errors caused by non-specific digestion or incomplete digestion can be measured and used to adjust the raw results and thus increase specificity. The method can detect differences in methylation status if these are more than 10%. No specialized equipment is required beyond the real-time PCR system and the method can be adapted for any of the 53 commercially available methylation-sensitive restriction enzymes.