Local application of nucleus pulposus induces expression OF P2X3 in rat dorsal root ganglion cells.

The P2X(3) receptor is a ligand-gated cation channel that is activated by extra cellular adenosine triphosphate (ATP) found in the dorsal root, trigeminal and nodose ganglia. It is one of the receptors transmitting nociceptive information of injuries and inflammation of the periphery by endogenous ATP released from damaged cells. The present study was performed in order to evaluate if there was an increased expression of P2X(3)-immunoreactivity in dorsal root ganglion (DRG) neurons after experimental disc herniation. There were four groups: exposure of the left L4 dorsal root ganglion and incision of the L4-L5 disc, exposure and slight displacement of the left L4 dorsal ganglion, sham exposure of the L4 dorsal root ganglion, and normal. Seven days after surgery, the DRG's were collected, sectioned and stained immunohistochemically for the P2X(3) receptor. The expression of P2X(3) increased significantly following incision of the L4-5 disc compared to the normal group. Sham surgery induced a minor, although statistically significant increase. Mechanical displacement did not induce any increased expression of the receptors. The study demonstrates that expression of the P2X(3)receptors in the DRG may be induced by local application of nucleus pulposus. This may increase our understanding of the pathophysiologic mechanisms related to disc herniation and sciatica.

Effect of methotrexate on fracture healing.

Low doses of methotrexate (MTX) are safe and effective for treating adult and juvenile rheumatoid arthritis. However, because this powerful anti-inflammatory drug might negatively influence the healing of wounds and fractures, MTX administration is often stopped during surgical procedures. The present study assesses the effects of low- and high-dose MTX on early inflammatory processes and bone healing in an experimental model of fracture. Thirty male Sprague-Dawley rats were assigned to low- and high-dose MTX and control groups. A femur was cut using a reciprocating saw and a 2-mm fracture gap was made using a fixator. One or four weeks thereafter, macrophages were immunostained and new bone formation was histomorphometrically measured. Significantly less new bone was formed in the high-dose MTX, than in the control group (p< 0.01), whereas bone formation did not significantly differ between the low-dose MTX and control groups. These results suggested that a low dose of MTX does not affect the early process of endochondral bone formation during fracture healing, whereas a high dose might delay the progress of new periosteal bone formation. Although more macrophages were found in the groups treated with MTX, their impact on surrounding inflammatory processes remains unclear.

Keishikajutsubuto (Guizhi-shu-fu-tang) treatment for refractory accumulation of synovial fluid in a patient with pustulotic arthro-osteitis.

We present a patient, a sixty-seven-year-old woman, who had refractory accumulation of synovial fluid in the knee joints with pustulotic arthro-osteitis for more than 10 years. Fifty ml of synovial fluid from her right knee contained 6,480 pg/ml of interleukin-8 (IL-8) and 15,000/mm3 of neutorophils. At first, she was treated with 400 mg/day of indomethacin farnesil (a prodrug that is converted to indomethacin after intestinal absorption) for 24 weeks. Although, the volume of synovial fluid in her right knee had decreased to 35 ml at the 16th week, it increased to 50 ml at the 24th week again. She was treated with Kampo medicine, Keishikajutsubuto (Guizhi-shu-fu-tang). In the present case, Keishikajutsubuto showed more therapeutic effect to pustulotic arthro-osteitis to reduce volume of synovial fluid to almost 0 ml, IL-8 concentration to 673 pg/ml and number of neutrophils to 660/mm3. Our data showed that Keishikajutsubuto might be suitable for this patient to regulate synovial fluid volume, reduce IL-8 concentration in synovial fluid, and block neutrophils migration to synovial fluid compared to indomethacin therapy.

Serotonin syndrome caused by minimum doses of SSRIS in a patient with spinal cord injury.

There have been only a few reports of serotonin syndrome developing after mono-therapy with a selective serotonin reuptake inhibitor (SSRI). We report a case of serotonin syndrome caused by long-term therapy with fluvoxamine prior to treatment with paroxetine. An 18-year-old man with spinal cord injury (SCI) at thoracic level 2-3 presented with onset of serotonin syndrome after taking fluvoxamine (50 mg per day) for 8 weeks prior to treatment with paroxetine (10 mg per day) for 6 days. He had confusion, agitation, severe headache, tachycardia (124 beats/minute), hypertension (165/118 mmHg), high fever (39.1 degrees C), and myoclonus. All of the symptoms disappeared within 24 hours after discontinuation of administration of paroxetine. This is an interesting case of serotonin syndrome that developed after minimum doses of single therapy with an SSRI in a patient with SCI.

An anatomic study of the sacral hiatus: a basis for successful caudal epidural block.

STUDY DESIGN: An anatomic study of the sacral hiatus using isolated sacra. OBJECTIVES: To clarify the anatomic variations of the sacral hiatus using the bony landmarks of the sacrum for improving the reliability of caudal epidural block (CEB). BACKGROUND DATA: The CEB has been widely used for the diagnosis and treatment of lumbar spinal disorders. The reliability of CEB is 70%-80% in the literatures. The cause of failure of CEB may depend on anatomic basis. METHODS: A total of 92 isolated sacra were used in this study. The bony landmarks were sacral hiatus and sacral cornua. Morphologic types of the sacral hiatus were classified using these landmarks. Also, location of the apex of sacral hiatus, diameter of the sacral canal at the apex of sacral hiatus, and the distance between bilateral cornua were measured. Two orthopedic surgeons performed measurements independently. RESULTS: Forty-two percent of the cases have both hiatus and cornu. Four percent of the cases showed the absent hiatus. The apex of sacral hiatus existed at the level of S4 vertebrae in 64% of the cases. The average diameter of the sacral canal was 6.0 +/- 1.9 mm. The average distance of bilateral sacral cornua was 10.2 +/- 0.35 mm. There were closed hiatus in 3% of cases. CONCLUSIONS: The sacral hiatus has anatomic variations. Understanding of these variations may improve the reliability of CEB.