Yukihiro Kato

Lobular capillary hemangioma of the oral mucosa: clinicopathological study of 43 cases with a special reference to immunohistochemical characterization of the vascular elements.

Clinical and histopathological features were investigated in 43 cases of oral lobular capillary hemangiomas (LCH) with a special reference to characteristics of the vascular elements. The lesions affected females more than males by a ratio of 1:1.5. Average age of the patients was 52.7 years. The lesions involved the gingiva (n = 15), the tongue (n = 13), the labial mucosa (n = 10) and other sites. The lesions appeared usually as a pedunculated mass with ulceration; size of the lesions was up to 15 mm. Histologically, a lobular area and an ulcerative area were distinguished. The density of vessels was about 1045/mm2 and 160/mm2 in the lobular and ulcerative areas, respectively. The average diameter of the vascular lumen was 9.1   5.6 mm (range: 2.8–42.0 mm) and 18.8  20.9 mm (range: 5.6–139.7 mm) in the lobular and ulcerative areas, respectively. In the lobular area, most of the vessels had an inner layer of endothelial cells showing positive reaction for von Willebrand factor (vWF) and CD34, as well as an outer layer of mesenchymal cells showing positive reaction for alpha‐smooth muscle actin (ASMA). However, in the ulcerative area, there was a variety of types of vessels consisting of various proportions of both endothelial and ASMA‐positive perivascular mesenchymal cells. These results indicate that most of the vascular elements in the lobular area resemble more pericapillary microvascular segments than they do capillaries. Thus, the authors propose the term ‘lobular pericapillary hemangioma’ to represent this type of lesion.

Involvement of phosphatidylcholine hydrolysis by phospholipase C in prostaglandin F2Α-induced 1,2-diacylglycerol formation in osteoblast-like MC3T3-E1 cells

We previously demonstrated that a prostaglandin F2Α (PGF2Α)-induced, sustained increase in 1,2-diacylglycerol (DAG) production was important for proliferation in osteoblast-like MC3T3-E1 cells. The 1,2-DAG formation is mediated by various enzymes, such as phos-phoinositide (PI)-specific phospholipase C (PLC), phospholipase D (PLD), and phosphatidylcholine (PC)-specific phospholipase C (PC-PLC). In the present study, to elucidate the mechanism of the 1,2-DAG formation, we have examined the PGF2Α-induced production of [3H]phosphorylcholine, a product of PC-PLC activity, in [3H]choline-labeled MC3T3-E1 cells. The PGF2Α-induced [3H]phosphorylcholine production was inhibited by genistein, a potent protein tyrosine kinase inhibitor, and increased by vanadate, a potent protein tyrosine phosphatase inhibitor. However, there were no effects after treatment with protein kinase C (PKC) inhibitors, the guanosine triphosphate (GTP) binding protein activator, NaF/AlCl3, a Ca2+-ionophore, or the potent activator of PKC, phorbol 12-myristate 13-acetate (PMA), suggesting that a tyrosine kinase(s) was involved in the PGF2Α-induced [3H]phosphorylcholine formation. Furthermore, a PGF2Α analogue, 16-(3-trifluoromethylphenoxy)-Ω-tetranor-trans-Δ2 PGF2Α methyl ester (ONO-995), stimulated the proliferation of MC3T3-E1 cells to a level similar to that seen with PGF2Α, and also caused phosphorylcholine and 1,2-DAG generation. However, neither an increase in intracellular free calcium ion ([Ca2+]i) levels by PI-PLC, nor phosphatidylethanol formation (and choline production) by PC-PLD were observed. From these results, we conclude that PGF2Α-induced 1,2-DAG accumulation was mediated mainly via tyrosine kinase(s)-dependent PC hydrolysis by PLC activity in osteoblast-like MC3T3-E1 cells.

Parapharyngeal and Retropharyngeal Space Infection of Odontogenic Origin

Abstract This report is of a 64-year-old woman with insulin-dependent diabetes and hypertension with a parapharyngeal and retropharyngeal space infection of odontogenic origin. The patient presented with submandibular swelling. After treatment with antimicrobial agents and diabetes control measures, she had initial improvement. Progressive dysphagia, increasing neck pain, and mild dyspnoea occurred on day 8, and imaging revealed abscess formation in the parapharyngeal and retropharyngeal spaces requiring transcervical drainage. On day 15, the associated teeth were extracted. She recovered uneventfully and was discharged from hospital after 30 days.