Ryoichi Kawabe

Different frequencies of Streptococcus anginosus infection in oral cancer and esophageal cancer

Multiple cancers frequently occur in the upper aerodigestive tract. The high incidence rate of multiple carcinomas in this region is often explained in terms of involvement of the same underlying risk factors. It has been reported that the oral bacterium Streptococcus anginosus (S. anginosus) is associated with esophageal, gastric, and pharyngeal cancer tissues. In this study, a highly specific quantification method for S. anginosus DNA using real‐time PCR was established. We employed this assay to determine whether S. anginosus is also associated with oral cancer tissues. This precise quantification method revealed different degrees of infection with S. anginosus in esophageal cancer and oral cancer. We assayed 10 ng of genomic DNA from cancer tissues, and found that eight of 18 samples (44%) from the esophagus contained a detectable level (>10 fg) of S. anginosus DNA, whereas this was the case for only five of 38 samples (13%) of oral cancer. The quantity of S. anginosus DNA in the esophageal cancer tissues was significantly higher than in oral cancer. The maximum amount of S. anginosus DNA was approximately ten times higher in esophageal than in oral cancer tissues. In addition, none of the five different oral cancer sites (floor of the mouth, mandibular gingival, maxillary gingival, buccal mucosal, and tongue) showed significant signs of S. anginosus infection. On the other hand, most non‐cancerous tissues of the esophagus and tongue showed an undetectable level of S. anginosus. These results suggest that S. anginosus is associated with esophageal cancer, but is not closely related with oral cancer.

Gene mutation analysis and immunohistochemical study of β-catenin in odontogenic tumors

In the present study the significance of nuclear/cytoplasmic expression of β‐catenin (CTNNB1) and mutation of the CTNNB1 gene (CTNNB1) in odontogenic tumors was examined. Six ameloblastomas (five follicular ameloblastomas and one plexiform ameloblastoma) and three malignant odontogenic tumors (one metastasizing ameloblastoma, one ameloblastic carcinoma, and one primary intraosseous odontogenic carcinoma) were investigated for CTNNB1 expression and CTNNB1 mutation. Immunohistochemically, all follicular ameloblastomas and one primary intraosseous odontogenic carcinoma exhibited focal and moderate nuclear/cytoplasmic expression of CTNNB1, whereas the plexiform ameloblastoma and the remaining two malignant odontogenic tumors had entirely membranous expression. CTNNB1 mutation at codon 40 of exon 3 was found in one of the six follicular ameloblastomas. The other five follicular ameloblastomas, the plexiform ameloblastoma, and the three malignant odontogenic tumors did not show mutation in exon 3 of CTNNB1. These findings further confirmed that CTNNB1 mutation is not frequent in ameloblastoma and malignant odontogenic tumors, although the abnormality of Wnt signaling may be associated with some of these tumors.

A carrier for clinical use of recombinant human BMP-2: dehydrothermally cross-linked composite of fibrillar and denatured atelocollagen sponge

The clinical applicability of a dehydrothermally cross-linked composite of fibrillar and denatured atelocollagen sponge (DCFD-AS), as a carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2) was evaluated in the rat subcutaneous pouch. After four weeks, DCFD-AS with rhBMP-2 formed compact bone, without undergoing significant changes in shape and size, by means of intramembranous ossification. The ultimate size, shape and location of induced new bone was accurately controlled by the carrier. Low antigenicity of soluble atelocollagen, cross-linking without chemicals, the combination of gelatin with fibrillar collagen, and the spongy structure probably all contributed to new bone formation through intramembranous ossification without inducing an inflammatory response. Atelocollagen sponge is easily sterilized, can be stored at room temperature, and can act as a rhBMP-2 carrier without the need for complex procedures.

Benign and Malignant Oncocytoma of the Salivary Glands with an Immunohistochemical Evaluation of Ki-67

We present two cases of benign oncocytoma derived from the parotid gland and minor salivary gland and one case of malignant oncocytoma from the parotid gland. The proliferative activity of the tumor cells was evaluated immunohistochemically for Ki-67. The average frequency of Ki-67-positive cells was 3.3% in the benign oncocytomas and 6.5% in the malignant oncocytoma. The higher frequency of Ki-67-positive cells in the malignant oncocytoma might reflect active cell proliferation. Ki-67 immunostaining may be useful in distinguishing a benign oncocytoma from a malignant oncocytoma.

Differential diagnosis of cervical lymphadenopathy with intranodal color Doppler flow signals in patients with oral squamous cell carcinoma.

OBJECTIVE The purpose of this study was to differentiate reactively enlarged cervical nodes from metastatic nodes by means of color Doppler flow imaging in patients with oral squamous cell carcinoma. STUDY DESIGN Enlarged lymph nodes with long-axis diameters greater than 10 mm in 30 patients were classified into 4 groups according to color Doppler flow imaging findings. After the patients underwent neck dissection, the findings were correlated with the pathologic features. RESULTS Color Doppler flow imaging detected 58 enlarged nodes with long-axis diameters greater than 10 mm. Thirty-five lymph nodes showed no color flow signals; of these, 32 (91%) were metastatic and 3 were reactive. Of the 12 lymph nodes with central color flow signals, 11 (92%) were reactively enlarged and 1 was metastatic. CONCLUSIONS The presence of central signals on color Doppler flow imaging appeared to be a significant parameter associated with reactively enlarged benign nodes in patients with oral squamous cell carcinoma.

Comparison between hockey stick and reversed hockey stick incision: gently curved single linear neck incisions for oral cancer

Hockey stick incision (HSI) and reversed-HSI are known to be useful incisions for lymph node dissections of the neck. Both are gently curved single linear incisions without three-point suture line junctions, but are different at the base of the skin flap. The HSI allows the elevation of a superiorly-based single cervical skin flap and the reversed-HSI allows for an inferiorly-based flap. We compared the viability of the skin flaps, exposure of the operation field and cosmetic results to evaluate the characteristics of each incision. HSI appeared to be the suitable incision for radical neck dissection due to adequate exposure of the operation field while rendering excellent cosmetic results. Reversed-HSI was applied in combination with block resection of parts of the oral cavity because it provided much better exposure of the operation field than HSI, while still achieving acceptable cosmetic results. Using this technique, a small area of marginal necrosis was occasionally seen at the apex of the skin flap due to poor blood supply.

Modulation of the incidence of hamster pulmonary endocrine cell hyperplasia by unilateral collapse of the lung

We evaluated the effects of the unilateral collapse of the left lung on the formation of pulmonary endocrine cell hyperplasia (PECH) induced by 4-nitroquinoline 1-oxide (4NQO) in Syrian golden hamsters. Ten hamsters were injected subcutaneously with 20 mg/kg body weight of 4NQO, once a week for 4 weeks and treated with injection of silicone rubber into the left thorax at the 8th experimental week. Another 30 animals were divided into three groups: treated with 4NQO only, left lung collapse only, and vehicle only. All animals were sacrificed at the 30th week. The lung tissues were embedded in paraffin; 50 serial sections were made from the tissues of each animal and were studied histologically and immunohistochemically. PECH showed a positive immunostain for calcitonin and/or serotonin. In the uncollapsed right lungs of the animals treated with both 4NQO and unilateral collapse, the mean incidence of PECH was 12.2 x 10(-2)/mm3 lung volume; the incidences of PECH in the animals treated with 4NQO only, collapse only, and vehicle only were 4.1, 3.8, and 1.4 x 10(-2)/mm3, respectively. In the collapsed left lungs, PECH did not form, regardless of 4NQO treatment. This study demonstrates that unilateral collapse of the lung modulates the incidence of PECH induced by 4NQO in hamsters.

Utilization of therapeutic embolization in haemorrhage caused by carcinoma of the tongue

Selective transcatheter arterial embolization, using Gelfoam, was performed in 2 patients with bleeding from tongue arteries due to carcinoma. Though the patients were in poor general condition, being in the terminal stage of cancer, there were no complications and the bleeding was successfully controlled. This method was effective in controlling haemorrhage from the tongue due to carcinoma of the tongue.

Antiphospholipid antibody syndrome. A patient with serious thrombocytopenia who underwent oral surgery.

Antiphospholipid antibody syndrome (APS) is characterized by thrombocytopenia, habitual abortion, and arteriovenous thrombosis.We report the case of a 32-year-old man with APS in whom an erupted maxillary third molar had to be extracted. The tooth was extracted while carefully monitoring hemostasis because of the presence of thrombocytopenia (2.4×104/μl). The wound healed without any local or systemic complications.When patients with APS are referred to oral and maxillofacial surgeons, it is important to be aware of APS, especially with regard to the perioperative care of general arteriovenous thrombosis and oral hemostasis.

Clinical study on treatment of oral cancer in extreme elderly patients.

1982年から1992年までの11年間に横浜市立大学医学部口腟外科で治療した80歳以上の頭頸部悪性腫瘍患者は29名であった。内訳は男性12名, 女性17名で26例が一次症例で3例が二次症例であった。病理学的診断では26例 (90%) が扁平上皮癌であった。部位別では舌が7例, 頬粘膜と上顎歯肉が各6例と多かった。病期分類では, Stage Iが2例, Stage IIが8例, Stage IIIが5例, Stage IVが12例であった。治療態度から手術群, 根治的放射線治療群, 姑息的治療群の3群に分類し, Kaplan-Meier法で生存率を検討した。手術群は3年, 5年とも15%, 放射線治療群は3年, 5年とも30%であり姑息群は1年で0%になった。根治治療群の治療成績は, Stage IとStage IIが5年で50%でStage IIIとStage IVは3年で0%になった.残念にも7例 (50%) が非担癌で他病死した。これは非常に高率であり, 超高齢者における悪性腫瘍治療の特徴を示していた。これらの結果から, 超高齢者の治療で最も大切な事は, 全身状態ならびに精神状態を十分検討の上適切な治療法を選択することである。実際にそれを評価する上でParformance Statusが最も有効な情報であった。なぜならば超高齢者ではQOLを維持しながら治療しなければならないからである。