Application of dynamic contrast-enhanced MRI to differentiate malignant lymphoma from squamous cell carcinoma in the head and neck

Because malignant lymphoma, the second most common malignant tumor of the head and neck, and squamous cell carcinoma (SCC), the most common malignant tumor of the head and neck, require different treatments, it is important to be able to differentiate them. In the present study, we attempted to differentiate malignant lymphomas from SCCs using dynamic contrast-enhanced MRI (DCE-MRI). Seventeen lesions (in 8 cases) of malignant lymphoma and 30 cases of SCC were compared by DCE-MRI. Thirteen of 17 malignant lymphomas (76.5%) showed the maximum contrast index (CI) at 90–180 s, while 26 of 30 SCCs (86.7%) showed the maximum CI at a much faster 60–105 s. There was a statistically significant difference between SCC and malignant lymphoma in the time needed reach the maximum CI (p=0.0177). There was also significant difference between SCC and malignant lymphoma in their maximum CIs (p&#60;0.001), with the maximum CIs of 29/30 SCCs (96.7%) above 2.0, while 12/17 malignant lymphomas (70.6%) showed CIs of less than 2.0. We consider these findings to be useful for distinguishing lymphomas from SCCs.</p

RESOLUTION PROPERTIES OF CRT MONITORS

We have developed a new technique for measuring the modulation transfer function (MTF) of a cathode ray tube (CRT) monitor. The "nominal" MTF was measured by displaying a line image of a width of one pixel on the CRT monitor using the pattern generator. We also measured the effective pixel width. In order to obtain the "actual" MTF, the nominal MTF was divided by the sinc function which is the Fourier transform of the effective pixel width. The results indicate that the corrected MTF　converges to the constant value as the effective pixel width is narrower. Thus, the actual MTFs were determined and compared in the horizontal direction for two CRT monitors

21セイキ ノ カンドウミャク インターベンション

Coronary intervention has come to achieve good results with the use of new devices, such as Rotablator (ROTA), new directional coronary atherectomy (DCA), and a special guide wire, even for lesions in which good results were not obtained with plain old balloon angioplasty. In the present study, we evaluated the initial results in patients who underwent ROTA procedures, coronary intervention for chronic total occlusion (CTO), and new DCA procedures in our hospital between January and December 2001. (1) There were 99 patients who underwent ROTA, with an average age of 68±12 years, a lesion length of 15.9±9.9 mm, a reference vessel diameter of 2.7±0.6 mm, and a success rate of 98%. Among these 99 patients, there were 82 patients (83%) with B2 or C type lesion, which is difficult to treat. (2) There were 61 patients with CTO who underwent coronary intervention, with an average age of 63±9 years, an occlusion length of 22.8±13.3 mm, a reference vessel diameter of 2.6±0.7 mm, and a success rate of 82%. (3) There were 5 patients who underwent DCA for ostial lesion of left anterior desending artery and the target lesion was successfully dilated in all these patients. These results indicated that new devices for coronary intervention have made it possible to treat a wider range of lesions, but restenosis still remains to be solved. In Europe and the U.S.A., restenosis is reported to have been drastically reduced by drug eluting stents, which are expected to be introduced in Japan in the future

Effects of demethylating agent 5-aza-2 '-deoxycytidine and histone deacetylase inhibitor FR901228 on maspin gene expression in oral cancer cell lines

Maspin, which belongs to the serine protease inhibitor (serpin) superfamily, has been proposed as a potent tumor suppressor that inhibits cell motility, invasion, angiogenesis, and metastasis. In the present study, we examined the effects of 5-aza-2'-deoxycytidine (5-aza-dC), a demethylating agent, and FR901228, a histone deacetylase (HDAC) inhibitor, on maspin expression in oral cancer cell tines. The expression levels of maspin mRNA were divided into two groups, which was the maspin tow-expressed and high-expressed cell lines in the 12 oral cancer cell lines. The maspin promoter contained only a few methylated CpG sites in the maspin low-expressed cell lines. Moreover, the methylation status was not altered after 5-aza-dC treatment. However, the transcription of the maspin gene was clearly increased following 5-aza-dC treatment in a number of oral cancer cell tines. These results imply that an action of 5-aza-dC is separate from induction of promoter demethylation. Treatment with FR901228 resulted in a time-dependent stimulation of the re-expression of maspin mRNA as early as 4 h after treatment in the maspin downregulated cells. The re-expression of the maspin gene may contribute to the recuperation of biological functions linked to FR901228 such as an inhibitory effect on tumor angiogenesis and cell invasion. These results indicate that maspin and its target genes may be excellent leads for future studies on the potential benefits of FR901228, a HDAC inhibitor, in cancer therapy.</p

Assessment of MRI and dynamic contrast-enhanced MRI in the differential diagnosis of adenomatoid odontogenic tumor

The radiographical differentiation of adenomatoid odontogenic tumor (AOT) from dentigerous cysts, calcifying odontogenic cysts, calcifying epithelial odontogenic tumors, odontogenic keratocysts, and amelobastomas is sometimes difficult. We attempted to differentiate AOT from other lesions similar to AOT in radiographic findings using MRI. The MRI features of AOT in our 3 cases included homogeneous low SI in the cystic portion and homogeneous intermediate SI in the solid portion on T1WI, homogeneous high SI in the cystic portion and intermediate to slightly high SI in the solid portion on T2WI, and enhancement of only the solid portion on CE-T1WI although non of the sequences included SI of calcifications. The contrast index curves in the 3 cases of AOT showed a gradual increase to 300 s, which signified a benign tumor. These MRI features were characteristic features of AOT and might be a basis for differentiating AOT from the above possible lesions in radiographic examinations.</p

Role of O-6-methylguanine-DNA methyltransferase and effect of O-6-benzylguanine on the anti-tumor activity of cis-diaminedichloroplatinum(II) in oral cancer cell lines

The DNA repair enzyme, O-6-methylguanine-DNA methyltransferase (MGMT) modulates the effectiveness of alkylating agents. However, the relationship between MGMT and the sensitivities to other agents has not been explored. In the present study, the association between MGMT expression and the cellular sensitivity to the platinum agent, CDDP was examined in four human oral cancer cell tines. CDDP depleted MGMT protein and mRNA levels in all four cell tines. Two cell lines with low MGMT expression were sensitive to an alkylating agent, N-methyl-N'-nitro-N-nitrosoguanidine and CDDP, whereas two other cell tines with high MGMT expression were resistant to both agents. Furthermore, the addition of the MGMT inhibitor, O-6-benzylguanine (O-6-BG), invariably enhanced CDDP sensitivity. CDDP depleted MGMT expression, and CDDP sensitivity was enhanced by O-6-BG. These results provide valuable information about the relationship between MGMT expression and CDDP sensitivity in oral cancer chemotherapy. (c) 2005 Elsevier Ltd. All rights reserved. </p