Human growth plate contains aggrecan fragments that can be generated by m-calpain.

Growth plate is a cartilaginous structure responsible for longitudinal growth and calcification of long bones. Aggrecan is initially expressed within the growth plate but is lost during the course of calcification. Calcium-activated proteinases are believed to play a primary role in aggrecanolysis. In this study, m-calpain was shown to be expressed in a limited area of the growth cartilage at the lower hypertrophic zone. Confocal immunostaining demonstrated colocalization of m-calpain and the aggrecan product within the lower hypertrophic chondrocytes and in limited region of the pericellular matrix. Immunoblotting analysis identified anti-VPGVA-positive aggrecan product within the dissociative fractions of A1D1-A1D6 (densities 1.65, 1.56, 1.52, 1.47, 1.41, and 1.37 g/cm(3), respectively). These findings indicated that limited expression of m-calpain is colocalized with the appearance of calpain-related aggrecan products at the sites of aggrecanolysis and calcification, and suggested an important role of m-calpain in regulation of the growth plate process. The G1-G2-containing fragment of aggrecan remaining within the extracellular matrix (ECM) of the growth plate may contribute to the mechanical properties of the growth plate between the chondrocyte cell layers until bony replacement takes place.

G1-G2 aggrecan product that can be generated by M-calpain on truncation at Ala709-Ala710 is present abundantly in human articular cartilage.

To elucidate the specific function of m-calpain in the metabolism of aggrecan in human articular cartilage, the prevalence and localization of a large glycosaminoglycan-bearing aggrecan product generated by m-calpain in human osteoarthritis (OA) cartilage were investigated. Extracts of human OA articular cartilage were analysed by immunostaining using new polyclonal anti-VPGVA antiserum that detects the COOH terminal neoepitope IVTQVVPGVA(709) generated by m-calpain-related cleavage within the keratan sulphate rich region of human aggrecan. Immunoblotting analyses of aggrecan populations in guanidine hydrochloride-extracts showed that OA cartilages contained anti-VPGVA positive aggrecan products with the COOH terminal neoepitope ... VPGVA(709), resulting from truncation between the Ala(709)-Ala(710) m-calpain-related cleavage site. This aggrecan product consisted of two NH(2) terminal globular domain (G1 and G2) and KS side chains. Immunohistochemical staining showed that anti-VPGVA positive staining was localized within chondrocytes and spread to the surrounding interterritorial matrix. Confocal microscopic analysis showed subcellular colocalization of anti-VPGVA and anti m-calpain. These results indicate that the aggrecan product with the COOH terminal neoepitope VPGVA(709) is synthesized regularly by intracellular processing in chondrocytes, and is present abundantly as a limited form of aggrecan. M-calpain is the major candidate of the proteinase to generate this aggrecan product during the intracellular aggrecan processing.

Total spondylectomy of a symptomatic hemangioma of the lumbar spine.

A vertebral hemangioma with dural compression and neurological deficit is rare. We report a symptomatic lumbar vertebral hemangioma which was successfully managed with total spondylectomy. The patient was a 31-year-old man whose chief complaint was low back pain. He had a slight sensory disturbance in the right thigh. Plain radiography and magnetic resonance imaging (MRI) revealed a tumor in the second lumbar vertebra, which extended into the spinal canal, compressing the dura. A percutaneous needle biopsy did not provide a pathological diagnosis. Before surgery, the arteries feeding the tumor were embolized using coils. We performed a total spondylectomy of the second lumbar vertebra with anterior reconstruction with a glass ceramic spacer and posterior instrumentation. The intraoperative pathological examination revealed a hemangioma of the lumbar spine. At the 4-year follow-up examination, the patient is completely asymptomatic without evidence of tumor recurrence.

Cervical clear cell meningioma mimicking a vertebral metastasis.

Cervical vertebral involvement of clear cell meningioma is very rare. We report a case of clear cell meningioma in the cervical vertebral body in a 72-year old male. Seven years prior to this presentation, the patient underwent palliative surgery and posterior instrumentation for a cervical vertebral tumor at C5, which had been diagnosed as a metastatic renal cell carcinoma. On this admission, the patient presented with severe neck pain. Examination revealed hypesthesia on the left in a C6 nerve root distribution. Plain X-rays and MRI revealed an enlarging tumor in the C5 and C6 vertebral bodies. The tumor was resected via an anterior approach followed by fusion using a strut bone graft. Histological examination of the surgical specimen diagnosed a clear cell meningioma. Postoperatively, the patient achieved pain relief and resolution of the neurological deficit. At follow-up two years postoperatively, he remains asymptomatic. We emphasize that cervical clear cell meningioma with involvement of the vertebral bodies may mimic metastatic renal cell carcinoma.

Keratinocytes can differentiate into eccrine sweat ducts in vitro: involvement of epidermal growth factor and fetal bovine serum.

BACKGROUND: in addition to formation of an epidermal sheet and dermal substitution, reconstruction of skin that possesses functionality is an important goal for dermatologists. OBJECTIVE: we attempted to regenerate eccrine sweat glands in vitro. METHODS: we constructed skin equivalent models with various combination of normal human keratinocytes and fibroblasts and also examined the effect of various growth factors. RESULTS: we found that keratinocytes invaded the collagen gels and formed eccrine duct-like structures, only when (i) the culture media contained at least 15 ng/ml of epidermal growth factor (EGF) and fetal bovine serum (FBS), (ii) the keratinocytes were derived from young donors, and (iii) fibroblasts were present in the gel. Interestingly, when cultured under the same conditions eccrine gland duct cells were unable to invade the gel. Immunohistochemical analyses revealed induction of carcinoembryonic antigen by EGF at the inner part of the eccrine duct-like structures. Proliferating cell nuclear antigen was expressed mainly in basal layers of the epithelia but was not observed in the deeply invaded part. Cytokeratin profiles of the reconstructed epithelia were consistent with those of the regenerating epidermis and partly with the eccrine sweat duct. CONCLUSIONS: although not perfect model, these results indicate that 'young' keratinocytes could differentiate into/toward eccrine sweat ducts in vitro in the presence of EGF and FBS in cooperation with dermal fibroblasts.

Successful antibiotic treatment for subdural empyema and seizure due to methicillin-resistant Staphylococcus aureus as a complication of halo orthosis usage: a case report.

Halo orthosis is used for cervical spine fixation after spinal surgery or injury. Although superficial infection at pin sites occurs frequently, intracranial development of infection, including brain abscesses, is very rare. We experienced subdural empyema due to methicillin-resistant Staphylococcus aureus (MRSA) caused by intracranial penetration of halo pins. A 38-year-old woman with a 4-year history of rheumatoid arthritis experienced severe myelopathy due to atlanto-axial dislocation and vertical subluxation. Reduction and immobilization using a halo vest resulted in neurologic improvement; she later underwent occipital bone to C2 fusion using posterior instrumentation. Three months after halo orthosis fixation, she complained of a headache, experienced a generalized tonic-clonic seizure, and became unconscious for 10 min. Computed tomography revealed pneumoencephalus, and Gd-enhanced magnetic resonance imaging revealed edema, enhancement of the overlying dura in the left partial lobe, and subdural and subarachnoidal empyema. Following removal of the halo vest, there was a purulent discharge from the left-posterior pin site. Culture of the discharge was positive for MRSA. The patient was treated with intravenous vancomycin for 2 weeks, followed by cefozopran hydrochloride for 4 weeks. Her symptoms improved, and additional surgery was not required. At latest follow-up, 10 years after the seizure, she is neurologically stable without any recurrence of the infection.