Spinal extradural arachnoid cyst causing cord compression in a 15-year-old girl: a case report.

The authors describe the case of a fifteen-year-old girl with progressive paraparesis of the lower limbs that was caused by an intraspinal extradural dorsal arachnoid cyst at the level of Th 3-6. Diagnosis was established with MRI and MRI myelography. The latter revealed the CSF-like content of the cyst. The patient underwent laminotomy and en bloc resection of the cyst. Ligation of the pedicle of the cyst was done with laminoplasty. Quick and complete recovery was observed after surgery.

The combination of pamidronate and calcitriol reverses particle- and TNF-alpha-induced altered functions of bone-marrow-derived stromal cells with osteoblastic phenotype.

Periprosthetic bone loss after total joint arthroplasty is a major clinical problem resulting in aseptic loosening of the implant. Among many cell types, osteoblasts play a crucial role in the development of peri-implant osteolysis. In this study, we tested the effects of calcitriol (1alpha,25-dihydroxy-vitamin-D3) and the bisphosphonate pamidronate on titanium-particle- and TNF-alpha-induced release of interleukin-6 and suppression of osteoblast-specific gene expressions in bone-marrow-derived stromal cells with an osteoblastic phenotype. We monitored the expression of procollagen alpha1[1], osteocalcin, osteonectin and alkaline phosphatase mRNAs by Northern blots and real-time reverse transcription and polymerase chain reaction analyses. The release of various cytokines was also analysed by ELISA. We found that calcitriol or pamidronate could only partially recover the altered functions of osteoblasts when added alone. Only a combination of these compounds restored all the tested functions of osteoblasts. The local delivery of these drugs may have therapeutic potential to prevent or to treat periprosthetic osteolysis and aseptic loosening of implants.

Particulate wear debris activates protein tyrosine kinases and nuclear factor kappaB, which down-regulates type I collagen synthesis in human osteoblasts.

Particulate wear debris generated mechanically from prosthetic materials is phagocytosed by a variety of cell types within the periprosthetic space including osteoblasts, which cells with an altered function may contribute to periprosthetic osteolysis. Exposure of osteoblast-like osteosarcoma cells or bone marrow-derived primary osteoblasts to either metallic or polymeric particles of phagocytosable sizes resulted in a marked decrease in the steady-state messenger RNA (mRNA) levels of procollagen alpha1[I] and procollagen alpha1[III]. In contrast, no significant effect was observed for the osteoblast-specific genes, such as osteonectin and osteocalcin (OC). In kinetic studies, particles once phagocytosed, maintained a significant suppressive effect on collagen gene expression and type I collagen synthesis for up to five passages. Large particles of a size that cannot be phagocytosed also down-regulated collagen gene expression suggesting that an initial contact between cells and particles can generate gene responsive signals independently of the phagocytosis process. Concerning such signaling, titanium particles rapidly increased protein tyrosine phosphorylation and nuclear transcription factor kappaB (NF-kappaB) binding activity before the phagocytosis of particles. Protein tyrosine kinase (PTK) inhibitors such as genistein and the NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC) significantly reduced the suppressive effect of titanium on collagen gene expression suggesting particles suppress collagen gene expression through the NF-kappaB signaling pathway. These results provide a mechanism by which particulate wear debris can antagonize the transcription of the procollagen alpha1[I] gene in osteoblasts, which may contribute to reduced bone formation and progressive periprosthetic osteolysis.

[Changes in the frequency of childhood brain tumors in North-East Hungary]. / A gyermekkori agydaganatok gyakoriságának változása Eszakkelet-Magyarországon.

Authors report about a seemingly increase of the number of pediatric brain tumors in Borsod county region North-East Hungary. In a retrospective study they conclude, that this phenomenon may to a great extent be artificial, that is, it may reflect the improvement of diagnostic possibilities, above all the new imaging modalities. At their Institution the pattern of brain tumors is similar to that reported in the literature. In addition a racial difference has been detected, since the gipsy population of this region seems to have lower incidence of pediatric brain tumor than the Hungarian majority.