Metastatic Maxillary Gingival Angiosarcoma with Aggressive Growth: A Case Report.

Angiosarcoma is a rare malignant tumor of endothelial origin. It is an aggressive neoplasm with early metastasis and poor prognosis and accounts for approximately 2% of all soft tissue sarcomas. Primary tumors arising in the oral cavity account for only 1% of all angiosarcomas. Here, we report a rare case of metastatic angiosarcoma of the gingiva originating from a primary mediastinal lesion. The patient was an 83-year-old man who presented with a maxillary interincisor tumor; it was a painless mass with rounded superficial necrosis measuring 23 mm× 17 mm on the labial side and 20 mm× 17 mm on the palatal side. The histopathological diagnosis was of an epithelioid angiosarcoma. Imaging revealed lesions in the mediastinum, lungs, liver, and skin. The primary lesion was considered a mediastinal lesion. As the tumor had spread throughout the body, palliative therapy was administered. However, the patient's general condition deteriorated rapidly, and he died 3 weeks after the first visit. Identifying oral metastatic malignancies may result in detection of malignant tumors at other sites; thus, oral and maxillofacial surgeons must maintain a heightened awareness of angiosarcoma.

Inhibition of mast cell degranulation by melanin.

Melanin is a dark naturally occurring pigment produced in nature and in many organisms. Although several reports have demonstrated applications for melanins in various therapeutic treatments, to date, no research has examined the anti-allergic effect of melanin. In this study, we for the first time found that solubilized or synthesized soluble melanin acts as a potent inhibitor of the degranulation of mast cells. We found that squid-ink-derived melanin significantly inhibited antigen-IgE-FcεRI-mediated degranulation of the mucosal mast cell line RBL-2H3. A homogenized melanin nanoparticle prepared by laser ablation also clearly suppressed antigen-induced mast cell degranulation. We also successfully solubilized synthetic melanin in a neutral biochemical buffer and found that it also significantly inhibited IgE-sensitized mast cells. The anti-degranulation activity of synthesized melanin was abolished in the melanin fraction below 50-kD molecular weight. All melanins used in this study did not exert significant cell death. Signal transduction analysis revealed that melanin suppressed antigen-triggered phosphorylation of signaling molecules as well as calcium influx. Transmission electron microscopy revealed that homogenized melanin nanoparticles partially attached to the cell surface and some nanoparticles were internalized to the cell. Flow cytometry revealed that the number of FcεRI-bound IgE molecules was decreased by melanin. Fluorescence recovery after photobleaching analysis indicated that melanin attenuated both plasma membrane and cytoplasmic fluidity, implying that melanin increased their viscosities. In vivo experiments using passive systemic anaphylaxis (PSA) and passive cutaneous anaphylaxis (PCA) mouse models demonstrated that oral administration of melanin accelerated the recovery of decreased body temperature after antigen infection in PSA, and combination sensitization of IgE with melanin attenuated antigen-induced extravasation in PCA. These findings indicated that melanin exhibits preventative effects against IgE-mast cell-mediated anaphylaxis. This study provides the first evidence that homogenized melanin may be a potential therapeutic agent for diseases involving mast cells.

Improvement of human cell line activation test (h-CLAT) using short-time exposure methods for prevention of false-negative results.

Recently, animal testing has been affected by increasing ethical, social, and political concerns regarding animal welfare. Several in vitro safety tests for evaluating skin sensitization, such as the human cell line activation test (h-CLAT), have been proposed. However, similar to other tests, the h-CLAT has produced false-negative results, including in tests for acid anhydride and water-insoluble chemicals. In a previous study, we demonstrated that the cause of false-negative results from phthalic anhydride was hydrolysis by an aqueous vehicle, with IL-8 release from THP-1 cells, and that short-time exposure to liquid paraffin (LP) dispersion medium could reduce false-negative results from acid anhydrides. In the present study, we modified the h-CLAT by applying this exposure method. We found that the modified h-CLAT is a promising method for reducing false-negative results obtained from acid anhydrides and chemicals with octanol-water partition coefficients (LogKow) greater than 3.5. Based on the outcomes from the present study, a combination of the original and the modified h-CLAT is suggested for reducing false-negative results. Notably, the combination method provided a sensitivity of 95% (overall chemicals) or 93% (chemicals with LogKow > 2.0), and an accuracy of 88% (overall chemicals) or 81% (chemicals with LogKow > 2.0). We found that the combined method is a promising evaluation scheme for reducing false-negative results seen in existing in vitro skin-sensitization tests. In the future, we expect a combination of original and modified h-CLAT to be applied in a newly developed in vitro test for evaluating skin sensitization.

Synthesis and dimerization of chloro[10]cycloparaphenylene: a directly connected cycloparaphenylene dimer.

The first synthesis and dimerization of monochlorinated [10]cycloparaphenylene (chloro[10]CPP) are described. By assembling a chlorinated 1,4-diborylbenzene unit with brominated and borylated cis-1,4-diphenylcyclohexane units by Suzuki-Miyaura coupling, a triangle-shaped chloro-containing macrocycle was synthesized. The acid-mediated "cyclohexane-to-benzene" aromatization afforded chloro[10]CPP without losing the chloro group. By the action of Ni(0) complex, chloro[10]CPP was converted to a directly connected [10]CPP dimer, which would be an ideal precursor for the "carbon nanobelt".