Takahito Okuda

Molecular cloning and characterization of a novel human gene (HERNA) which encodes a putative RNA-helicase

A full-length cDNA encoding a novel protein was isolated and sequenced from a human hepatocellular cDNA library. This cDNA consists of 7037 base pairs and has a predicted open reading frame encoding 1924 amino acids. It possesses an RNA-helicase motif containing a DEXH-box in its amino-terminus and an RNase motif in the carboxy-terminus. From a striking homology to Caenorhabditis elegans K12H4.8, it might be a human homolog of the K12H4.8. PCR-based mapping with both a monochromosomal hybrid panel and radiation hybrid cell panels placed the gene to human chromosome 14q31 near the marker D14S605.

v-Src suppresses SHPS-1 expression via the Ras-MAP kinase pathway to promote the oncogenic growth of cells.

We investigated the effect of cell transformation by v-src on the expression and tyrosine phosphorylation of SHPS-1, a putative docking protein for SHP-1 and SHP-2. We found that transformation by v-src virtually inhibited the SHPS-1 expression at mRNA level. While nontransforming Src kinases including c-Src, nonmyristoylated forms of v-Src had no inhibitory effect on SHPS-1 expression, transforming Src kinases including wild-type v-Src and chimeric mutant of c-Src bearing v-Src SH3 substantially suppressed the SHPS-1 expression. In cells expressing temperature sensitive mutant of v-Src, suppression of the SHPS-1 expression was temperature-dependent. In contrast, tyrosine phosphorylation of SHPS-1 was rather activated in cells expressing c-Src or nonmyristoylated forms of v-Src. SHPS-1 expression in SR3Y1 was restored by treatment with herbimycin A, a potent inhibitor of tyrosine kinase, or by the expression of dominant negative form of Ras. Contrary, active form of Mek1 markedly suppressed SHPS-1 expression. Finally, overexpression of SHPS-1 in SR3Y1 led to the drastic reduction of anchorage independent growth of the cells. Taken together, our results suggest that the suppression of SHPS-1 expression is a pivotal event for cell transformation by v-src, and the Ras-MAP kinase cascade plays a critical role in the suppression.

Inhibitory effect of ND2001 on spontaneous multiple metastasis of NC 65 tumors derived from human renal cancer cells intradermally transplanted into nude mice.

The NC 65 tumor cell line derived from human renal cell carcinoma was selected from among nine human cell lines by determining the inhibition of invasion by ND2001 (sodium D-glucaro-delta-lactam) in vitro. The efficacy of this agent against these tumor cells was investigated in an experimental metastatic model of human tumors in vivo. Although ND2001 did not inhibit growth of NC 65 cells intradermally transplanted into male KSN mice (nu/nu), this agent inhibited multiple spontaneous metastasis.

Clinical usefulness of MLCs in robotic radiosurgery systems for prostate SBRT

Abstract Stereotactic body radiation therapy (SBRT) using recently introduced multileaf collimators (MLC) is preferred over circular collimators in the treatment of localized prostate cancer. The objective of this study was to assess the clinical usefulness of MLCs in prostate SBRT by comparing the effectiveness of treatment plans using fixed collimators, variable collimators, and MLCs and by ensuring delivery quality assurance (DQA) for each. For each patient who underwent conventional radiation therapy for localized prostate cancer, mock SBRT plans were created using a fixed collimator, a variable collimator, and an MLC. The total MUs, treatment times, and dose–volume histograms of the planning target volumes and organs at risk for each treatment plan were compared. For DQA, a phantom with a radiochromic film or an ionization chamber was irradiated in each plan. We performed gamma‐index analysis to evaluate the consistency between the measured and calculated doses. The MLC‐based plans had an ~27% lower average total MU than the plans involving other collimators. Moreover, the average estimated treatment time for the MLC plan was 31% and 20% shorter than that for the fixed and variable collimator plans respectively. The gamma‐index passing rate in the DQA using film measurements was slightly lower for the MLC than for the other collimators. The DQA results acquired using the ionization chamber showed that the discrepancies between the measured and calculated doses were within 3% in all cases. The results reinforce the usefulness of MLCs in robotic radiosurgery for prostrate SBRT treatment planning; most notably, the total MU and treatment time were both reduced compared to the cases using other types of collimators. Moreover, although the DQA results based on film dosimetry yielded a slightly lower gamma‐index passing rate for the MLC than for the other collimators, the MLC accuracy was determined to be sufficient for clinical use.

Role of PET/CT screening in detecting a second primary carcinoma in patients with malignant lymphoma

Dear Editor, Positron emission tomography/computed tomography (PET/CT) using F fluorodeoxyglucose (FDG) has come to be accepted for the diagnosis, staging, and treatment evaluation of malignant lymphoma [1, 2]. The uptake of F FDG is increased in most types of cancers as compared with normal organs [3]. Therefore, we sometimes come across cases with unsuspected findings in staging or in the follow-up of patients with malignant lymphoma [4]. We observed three cases of malignant lymphoma in which another carcinoma was detected in the initial staging. The effectiveness of detecting another carcinoma using FDG– PET in the initial tumor staging has been reported in the literature [5]. However, there is no report on the detection of a second primary carcinoma among a cohort of patients with malignant lymphoma. We retrospectively evaluated whether PET/CT is useful for detecting another carcinoma in initial staging of malignant lymphoma. From April 2006 to March 2010 at Toyota Memorial Hospital, all 113 patients in this analysis were initially diagnosed with malignant lymphoma, and all underwent PET/CT for the initial staging. The median age of the patients was 61 years (range, 16–88 years) at the time of diagnosis. The cases of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) made up threefourths of all patients (DLBCL, 50.4%; FL, 26.5%; peripheral T-cell lymphoma, 8.9%; extranodal NK/T-cell lymphoma, nasal type, 2.7%; extranodal marginal zone lymphoma of mucosa-associated lymphoma tissue, 2.7%; Hodgkin lymphoma, 8.8%). Seventy-one patients were at an advanced stage (61.9%). Thirty-nine patients showed an abnormal FDG uptake in extranodal sites except the bone marrow (34.5%). Fourteen patients underwent biopsy of extranodal sites except the bone marrow (12.4%). A second primary carcinoma was identified in three patients (2.7%). Table 1 shows the three cases of lymphoma with concurrent carcinoma. Three years have passed since cases 1 and 2 were diagnosed with lymphoma and a second primary carcinoma. They both underwent chemotherapy for lymphoma and surgical resection for carcinoma, and maintained remission. Case 3 was transferred to a local hospital after the diagnosis was confirmed because the patient desired to receive treatment locally. We were informed that she has remained in remission. Our study suggested that it was not rare to diagnose another carcinoma in patients with malignant lymphoma. We were able to detect a second primary carcinoma in the early stage. Early detection of a second primary carcinoma might contribute to a favorable prognosis and survival. Therefore, if abnormal FDG uptake in an extranodal site is detected at the time of initial staging, a biopsy should be performed to rule out a second primary carcinoma. The initial staging for lymphoma patients by FDG PET/CT may R. Sakemura (*) : J. Hiraga : S. Mizuno Division of Hematology, Toyota Memorial Hospital, Toyota, Japan e-mail: reona_sakemura@mail.toyota.co.jp

Inter-individual Comparison of Gadobutrol and Gadoteridol Tissue Time-intensity Profiles for Dynamic Susceptibility Contrast Perfusion MR Imaging

Purpose: Gadobutrol is a gadolinium-based contrast material (GBCM) with a high concentration of gadolinium and high relaxivity. Our purpose was to evaluate the signal intensity profiles in brain tissue for the bolus width and degree of signal change after bolus injection using an echo planar dynamic susceptibility contrast (DSC) sequence. We compared gadobutrol to gadoteridol using various injection speeds and saline flush volumes. Methods: We studied 97 patients who underwent brain MRI. Datasets for perfusion studies were acquired using a 3T scanner with an echo planar imaging (EPI) sequence. The injection protocols were set up with combinations of injection speed and saline flush volume for both gadobutrol and gadoteridol. The full width at half maximum (FWHM) and the maximum signal change ratio (SCRmax ) of the time intensity curves were measured. Results: The FWHM did not show a statistically significant difference according to injection speed, flush volume, or type of GBCM. The SCRmax showed a greater change with a faster injection speed, larger saline flush, and gadobutrol administration. The difference between gadobutrol and gadoteridol became smaller with a faster injection speed and a larger saline flush. Conclusion: The maximum signal drop was larger with gadobutrol when the injection speed was slow and the saline flush was small. Thus, gadobutrol may be useful to obtain a better profile for DSC perfusion MRI in conditions requiring a slower injection speed and/or a smaller volume of saline flush.

Intercept-PCR, an improvement for elevating performance to find a new member of a certain gene family.

We have established a method by which the performance of reverse transcriptase coupled polymerase chain reaction (RT-PCR) for seeking a new gene is improved. The actual procedure is quite easy: it is only to add several specific oligonucleotides into the reaction mixture of the usual RT-PCR. To verify the effectiveness of this method is also easy: it is only to detect the PCR products in the preliminary experiment. The finding in the present study provides valuable information for gene cloning tactics.