Tsunehiro Shimosato

Mandibular adenomatoid odontogenic tumor with unusual clinicopathologic features

Abstract Adenomatoid odontogenic tumor (AOT) is a relatively uncommon odontogenic tumor characterized by the formation of ductlike structures by the epithelial component of the lesion. 1 According to the reports of Giansanti et al, 2 Toida et al, 3 and Philipsen et al, 4 cases occur predominantly in the second and third decades of life, with few cases occurring in people over 50 years old. The usual site is the anterior maxillary region. The most common radiographic appearance of AOT is a sharply circumscribed, unilocular radiolucency, often associated with the crown of an unerupted anterior maxillary tooth (especially canine), resembling a dentigerous cyst. Detectable radiopacities were reported in two thirds of the cases. 4 The AOT reported here showed unusual clinicopathologic features.

Molecular cloning and sequence analysis of cDNA encoding δ4‐3‐ketosteroid 5β‐reductase of rat liver

A cDNA clone encoding δ4‐3‐ketosteroid 5β‐reductase was isolated from rat liver cDNA libraries using antibodies specific for the enzyme and oligonucleotides as probes. The cDNA contained 981‐base pair open reading frame encoding 327 amino acid residues (M, 37 376) and an unusually long 3′‐untranslated region rich in AT sequence in the total length of 3189 base pairs. The predicted amino acid sequence contains th sequences similar to the putative NADPH‐ and steroid‐binding regions.

Osteoma of the lateral pterygoid plate of the sphenoid bone

A rare case is reported of an osteoma protruding into the pterygomandibular space from the lateral pterygoid plate of the sphenoid bone. The procedure of the diagnosis and treatment is described. In this case, computed tomography (CT) was the most useful in making a differential diagnosis. That the pulling force of the medial pterygoid muscle might be a causative agent in the growth of this osteoma is considered.

A new method of conserving the inferior alveolar nerve during resection of the mandible

A method is presented of conserving the inferior alveolar nerve where resection of the mandible is necessary. The technique features the delivery of the nerve through the mandibular foramen and the end-to-end anastomosis of the previously sectioned nerve. The technique is particularly indicated in the treatment of carefully chosen cases of benign and locally invasive neoplasms and cysts with complex cavities.

A multifocal schwannoma of the masseteric nerve causing hemicrania

A case is reported of schwannoma of the right masseteric nerve, invading the pterygopalatine fossa and the parapharyngeal space through the mandibular notch in a 61-year-old woman. The tumor in this case was composed of four various-sized interconnected nodules, simulating a string of beads. The tumor was the cause of the patients chronic hemicrania, as confirmed by the relief from and disappearance of head pain after surgical removal of the tumor. The most important aspects of this case are the anatomic site of the schwannoma and its uncommon clinicopathologic manifestations; this tumor originated from the masseteric nerve and is the first case reported to straddle the mandibular notch.

delta 4-3-Oxosteroid 5 beta-reductase. Structure and function.

delta 4-3-Oxosteroid 5 beta-reductase catalysing reduction of delta 4-3-oxosteroids to give A/B cis-conformation was intraperitoneally injected into BALB/c strain mice with Ribi adjuvant. Monoclonal antibody specific for this enzyme was prepared from their spleen cells. Using this monoclonal antibody as a probe the enzyme was further purified using reversed phase liquid chromatography to determine amino-acid sequence protein-chemically. Attempts to determine the N-terminal amino acid failed, indicating that the N-terminal amino acid is blocked. The protein was therefore subjected to digestion with lysyl endopeptidase after alkylating with iodoacetate. The peptides thus formed were isolated and purified by reversed-phase high-performance liquid chromatography and their amino-acid sequences were determined. Using antibodies and oligonucleotides as probes a cDNA which contained a 978 bp long open reading frame encoding 326 amino-acid residues (Mr 37376) was isolated from rat liver cDNA libraries and the entire sequence of the protein was deciphered from its nucleotide sequence. The COS cells transfected with this cDNA revealed a versatile activity to reduce varied kinds of delta 4-3-oxosteroids, i.e. 7 alpha-hydroxy-4-cholesten-3-one, androstenedione and cortisone as postulated by Okuda and Okuda (1984, J. Biol. Chem. 259, 7519-7524) and Furuebisu et al. (1987, Biochim. Biophys. Acta 912, 110-114. With a newly established immunoblotting assay method several tissues and organs were surveyed and it was found that the enzyme exists only in the liver and there is an apparent difference between sexes as to the content of this enzyme. However, there was little if any difference in the amount of mRNAs between both sexes, which may indicates that the sexual difference of rat liver cytosol 5 beta-reductase is due to a posttranslational modification and/or degradation.

Phenotypic expression of human epidermal growth factor in foetal submandibular gland and pleomorphic adenoma of salivary gland

The phenotypic expression of the human epidermal growth factor (EGF) was investigated immunohistochemically in human foetal submandibular glands from the 5th to 10th month of gestation, adult normal submandibular glands and 48 cases of pleomorphic adenomas. In foetal submandibular glands, both the terminal buds and primary ducts at the intermediate stage of gestation were positive for EGF, and in particular, the outer layer cells of primary ducts showed strong EGF-immunoreactivity. EGF-positive cells decreased as the gestational stage advanced and only ductal cells were weakly positive for EGF at the terminal stage of gestation. In the adult normal submandibular gland, weak immunoreactivity for EGF was restricted to ductal cells. However, 41 (86%) of the 48 pleomorphic adenomas had EGF-positive cells which were distributed among the ductal, chondroid and myxoid portion. No EGF-immunoreactivity was detected in the solid portion of pleomorphic adenomas. These results suggest that EGF may play an important role in the growth and differentiation of foetal cells as well as the proliferation of tumour cells in pleomorphic adenomas.