A case of tumoural calcinosis in the temporomandibular joint associated with systemic sclerosis.

Systemic sclerosis (SSc) is a relatively rare condition characterized by the excessive production and deposition of collagen within tissue. This condition is thought to be immunologically mediated and, in addition to its notorious cutaneous manifestations, often involves multiple organs. A case is presented of systemic sclerosis associated with extensive tumoural calcinosis in the temporomandibular joint. There has been no evidence of recurrence or complications during approximately 2 years of follow up, but long-term follow up is essential.

Experimental study of reconstruction of the temporomandibular joint using a bone transport technique.

PURPOSE: This study investigated the applicability of transport distraction osteogenesis with an internal appliance for reconstruction of the temporomandibular joint (TMJ). MATERIALS AND METHODS: Fifteen millimeters of the ascending ramus, including the condyle and intra-articular disc, was extirpated in 42 white rabbits (3.0 kg weight). After an L-osteotomy was performed from the anterior border of the coronoid process to the posterior border of the mandible, an internal distraction appliance was applied. The transport segment was advanced 0.9 mm/day for 14 days after a 14-day healing period. During a 24-week period after the completion of the lengthening, the rabbits were killed at various intervals. RESULTS: Eight weeks after the completion of the lengthening, the distraction gap between the transport segment and the preexisting mandible was indistinguishable in the radiographs. New bone and a large amount of cartilage were observed microscopically in the distraction gap. New bone was also observed at the leading edge of the transport segment. This bone seemed to form from the surrounding periosteum. At 8 weeks after the completion of lengthening, the mature cortical bone was reconstructed. A collagenous-like structure formed a cap over the leading edge of the transport segment. This cap may substitute for an articular disc. The new bone remodeled and resembled the condyle. CONCLUSION: The bone transport technique is promising for the reconstruction of TMJ.

Correction of cleft lip nasal deformity in Orientals with a cantilevered iliac bone graft.

We describe our technique for correcting a nasal deformity associated with cleft lip in oriental people. Cantilevered iliac bone grafts are used to provide additional structural support and to achieve the desired nasal projection and profile. Augmentation of the nasal bridge creates the illusion of a narrower nose. This technique was used in 20 patients with severe nasal deformities. Clinically and radiographically it consistently produced good, long-lasting results.

Autocrine action and its underlying mechanism of nitric oxide on intracellular Ca2+ homeostasis in vascular endothelial cells.

The rise in cytosolic Ca(2+) concentration (Ca(2+)(i)) in vascular endothelial cells (ECs) activates the production and release of nitric oxide (NO). NO modifies Ca(2+)(i) homeostasis in many types of nonendothelial cells. However, its effect on endothelial Ca(2+)(i) homeostasis at basal and excited states remains unclear. In the present study, to elucidate the effect of NO on basal Ca(2+)(i), inositol 1,4,5-trisphosphate-induced Ca(2+)(i) release (IICR) was blocked by expressing an antisense against type-1 inositol 1,4,5-trisphosphate receptors or by microinjecting heparin to individual ECs, and the effects of NO that was released by and diffused from adjacent IICR-intact ECs were recorded. After ATP or bradykinin stimulation, IICR-inhibited ECs showed a marked reduction of basal Ca(2+)(i), which was abolished by N(G)-monomethyl-l-arginine monoacetate pretreatment. The reduction disappeared in sparsely seeded ECs. Exogenous NO gas mimicked the effect of ATP or bradykinin to reduce basal Ca(2+)(i). Blocking plasma membrane Ca(2+)-ATPase (PMCA), but not Na(+)-Ca(2+) exchange or sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase, suppressed the reduction, indicating that the reduction resulted from a NO-dependent potentiation of PMCA. To elucidate the effect of NO on elevated Ca(2+)(i), ATP-, bradykinin-, or thapsigargin-evoked Ca(2+)(i) response in the presence and absence of NO production was compared in adjacent IICR-intact ECs. NO was found to potentiate PMCA, which, in turn, greatly attenuated agonist-evoked Ca(2+)(i) elevation. NO also potentiated Ca(2+) influx, which markedly increased the sustained phase of Ca(2+)(i) elevation and possibly NO production. NO did not affect other Ca(2+)(i)-elevating and Ca(2+)(i)-sequestrating components. Thus, NO-dependent potentiation of PMCA is crucial for Ca(2+)(i) homeostasis over a wide Ca(2+)(i) range.

Peroxynitrite production by TNF-alpha and IL-1beta: implication for suppression of osteoblastic differentiation.

To determine the roles of nitric oxide (NO) and its metabolite, peroxynitrite (ONOO(-)), on osteoblastic activation, we investigated the effects of a NO donor [ethanamine, 2, 2'-(hydroxynitrosohydrazono)bis- (dNO)], an O(-2) donor (pyrogallol), and an ONOO(-) scavenger (urate) on alkaline phosphatase (ALPase) activity and osteocalcin gene expression, which are indexes of osteoblastic differentiation. dNO elevated ALPase activity in the osteogenic MC3T3-E1 cell line. The combination of dNO and pyrogallol reduced both ALPase activity and osteocalcin gene expression. Because both indexes were recovered by urate, ONOO(-), unlike NO itself, inhibited the osteoblastic differentiation. Furthermore, treatment with a combination of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) was found to yield ONOO(-) as well as NO and O(-2). The reductions in ALPase activity and osteocalcin gene expression were also restored by urate. We conclude that ONOO(-) produced by TNF-alpha and IL-1beta, but not NO per se, would overcome the stimulatory effect of NO on osteoblastic activity and inhibit osteoblastic differentiation.

Secondary lengthening of the reconstructed mandible using a gradual distraction technique--two case reports.

We have performed mandibular lengthening to restore oral function in 2 cases after tumour resection. Both cases had already undergone a vascularised fibular graft for mandibular reconstruction and had severe contracture and absence of an alveolar ridge for dentures. Gradual distraction was applied after corticotomy of the fibular bone at 0.9 mm per day. After completion of bone lengthening of 20-30 mm, both patients underwent a split thickness skin graft to obtain a good alveolar ridge for dentures and implants. Osteointegrated implants have since been applied in one of these cases, and the other patient has been able to eat a normal diet using dentures. Gradual distraction is applicable for vascularised bone grafts and useful for restoration of the alveolar ridge to accommodate dentures in cases with severe contracture of the oral space after tumour ablation.

Direct action of nitric oxide on osteoblastic differentiation.

The effect of nitric oxide (NO) on osteoblastic differentiation was examined in cultured mouse osteoblasts. Interleukin-1beta and tumor necrosis factor-alpha expressed inducible NO synthase gene with little effect on constitutive NO synthase gene. These cytokines increased NO production, which was inhibited by L-NMMA pretreatment, and decreased alkaline phosphatase (AIPase) activity, which was not restored by L-NMMA. Furthermore, NO donors, sodium nitroprusside and NONOate dose-dependently elevated AIPase activity and expression of osteocalcin gene. These results suggest that NO directly facilitates osteoblastic differentiation and the cytokine-induced inhibition of AIPase activity is mediated via mechanism other than NO.