A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy

Son, Jaeman,Baek, Taesung,Lee, Boram,Shin, Dongho,Park, Sung Yong,Park, Jeonghoon,Lim, Young Kyung,Lee, Se Byeong,Kim, Jooyoung,Yoon, Myonggeun Versita, Warsaw 2015 Radiology and oncology Vol.49 No.3

<P><B>Background</B></P><P>This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used.</P><P><B>Materials and methods.</B></P><P>Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm.</P><P><B>Results</B></P><P>The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.88%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools.</P><P><B>Conclusions</B></P><P>QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA.</P>

Cannabinoid receptor activation inhibits cell cycle progression by modulating 14-3-3β

Jung, Hye-Won,Park, Inae,Ghil, Sungho Versita 2014 Cellular & molecular biology letters Vol.19 No.3

<P>Cannabinoids display various pharmacological activities, including tumor regression, anti-inflammatory and neuroprotective effects. To investigate the molecular mechanisms underlying the pharmacological effects of cannabinoids, we used a yeast two-hybrid system to screen a mouse brain cDNA library for proteins interacting with type 1 cannabinoid receptor (CB1R). Using the intracellular loop 3 of CB1R as bait, we identified 14-3-3β as an interacting partner of CB1R and confirmed their interaction using affinity-binding assays. 14-3-3β has been reported to induce a cell cycle delay at the G<SUB>2</SUB>/M phase. We tested the effects of cannabinoids on cell cycle progression in HeLa cells synchronized using a double-thymidine block-and-release protocol and found an increase in the population of G<SUB>2</SUB>/M phase cells. We further found that CB1R activation augmented the interaction of 14-3-3β with Wee1 and Cdc25B, and promoted phosphorylation of Cdc2 at Tyr-15. These results suggest that cannabinoids induce cell cycle delay at the G2/M phase by activating 14-3-3β.</P>

The usefulness of F-18 FDG PET/CT-mammography for preoperative staging of breast cancer: comparison with conventional PET/CT and MR-mammography

Moon, Eun-Ha,Lim, Seok Tae,Han, Yeon-Hee,Jeong, Young Jin,Kang, Yun-Hee,Jeong, Hwan-Jeong,Sohn, Myung-Hee Versita, Warsaw 2013 Radiology and oncology Vol.47 No.4

<P><B>Background</B></P><P>The objective of the study was to compare the diagnostic efficacy of an integrated Fluorine-18 fluorodeoxyglucose (F-18 FDG) PET/CT-mammography (mammo-PET/CT) with conventional torso PET/CT (supine-PET/CT) and MR-mammography for initial assessment of breast cancer patients.</P><P><B>Patients and methods</B></P><P>Forty women (52.0 ± 12.0 years) with breast cancer who underwent supine-PET/CT, mammo-PET/CT, and MR-mammography from April 2009 to August 2009 were enrolled in the study. We compared the size of the tumour, tumour to chest wall distance, tumour to skin distance, volume of axillary fossa, and number of meta-static axillary lymph nodes between supine-PET/CT and mammo-PET/CT. Next, we assessed the difference of focality of primary breast tumour and tumour size in mammo-PET/CT and MR-mammography. Histopathologic findings served as the standard of reference.</P><P><B>Results</B></P><P>In the comparison between supine-PET/CT and mammo-PET/CT, significant differences were found in the tumour size (supine-PET/CT: 1.3 ± 0.6 cm, mammo-PET/CT: 1.5 ± 0.6 cm, p < 0.001), tumour to thoracic wall distance (1.8 ± 0.9 cm, 2.2 ± 2.1 cm, p < 0.001), and tumour to skin distance (1.5 ± 0.8 cm, 2.1 ± 1.4 cm, p < 0.001). The volume of axillary fossa was significantly wider in mammo-PET/CT than supine-PET/CT (21.7 ± 8.7 cm<SUP>3</SUP><I>vs.</I> 23.4 ± 10.4 cm<SUP>3</SUP>, p = 0.03). Mammo-PET/CT provided more correct definition of the T-stage of the primary tumour than did supine-PET/CT (72.5% <I>vs</I>. 67.5%). No significant difference was found in the number of metastatic axillary lymph nodes. Compared with MR-mammography, mammo-PET/CT provided more correct classification of the focality of lesion than did MR-mammography (95% <I>vs</I>. 90%). In the T-stage, 72.5% of cases with mammo-PET/CT and 70% of cases with MR-mammography showed correspondence with pathologic results.</P><P><B>Conclusions</B></P><P>Mammo-PET/CT provided more correct definition of the T-stage and evaluation of axillary fossa may also be delineated more clearly than with supine-PET/CT. The initial assessment of mammo-PET/CT would be more useful than MR-mammography because the mammo-PET/CT indicates similar accuracy with MR-mammography for decision of T-stage of primary breast tumour and more correct than MR-mammography for defining focality of lesion.</P>

The GTPase domain of Galphao contributes to the functional interaction of Galphao with the promyelocytic leukemia zinc finger protein

Won, Jung Hee,Ghil, Sung Ho SP Versita 2009 Cellular & molecular biology letters Vol.14 No.1

<P>Go, one of the most abundant heterotrimeric G proteins in the brain, is classified as a member of the Gi/Go family based on its homology to Gi proteins. Recently, we identified promyelocytic leukemia zinc finger protein (PLZF) as a candidate downstream effector for the alpha subunit of Go (Gαo). Activated Gαo interacts with PLZF and augments its function as a repressor of transcription and cell growth. G protein-coupled receptor-mediated Gαo activation also enhanced PLZF function. In this study, we determined that the GTPase domain of Gαo contributes to Gαo:PLZF interaction. We also showed that the Gαo GTPase domain is important in modulating the function of PLZF. This data indicates that the GTPase domain of Gαo may be necessary for the functional interaction of Gαo with PLZF.</P>

The age-dependent induction of apoptosis-inducing factor (AIF) in the human semitendinosus skeletal muscle

Park, Soo Yeon,Kim, Ha Young,Lee, Jung Hwan,Yoon, Kyoung Ho,Chang, Mun Seog,Park, Seong Kyu SP Versita 2010 Cellular & molecular biology letters Vol.15 No.1

<P>To assess the dependence on age of the expression of apoptosis regulatory proteins in the human semitendinosus muscle, we measured the expression levels of several apoptosis-related genes, including apoptosis-inducing factor (AIF), Bax, Bcl-2, caspase-3 and heat shock protein 70 (HSP70), using RT-PCR, immunohistochemistry and TUNEL assays. We found that the DNA fragmentation was proportional to the age of the tissues sample donors. The expression levels of AIF were significantly elevated (by 10 to 25%) in semitendinosus tissue samples from older individuals, but the Bax, Bcl-2, caspase-3 and HSP 70 levels remained almost constant. This data suggests that the morphological and functional changes observed in aged human semitendinosus muscle correlates with the apoptosis of muscle cells through the induction of AIF.</P>

Capsaicin induces apoptosis by generating reactive oxygen species and disrupting mitochondrial transmembrane potential in human colon cancer cell lines

Yang, Kyung Min,Pyo, Jong Ok,Kim, Gyu-Yeol,Yu, Rina,Han, In Seob,Ju, Seong A.,Kim, Won Ho,Kim, Byung-Sam SP Versita 2009 Cellular & molecular biology letters Vol.14 No.3

<P>Although genetic factors are a well-known cause of colorectal cancer, environmental factors contribute more to its development. Despite advances in the fields of surgery, radiotherapy and chemotherapy, the cure rates for colon cancer have not substantially improved over the past few decades. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), the principal pungent ingredient of hot chili pepper, has exhibited an anti-tumor effect in many cell types. However, the mechanisms responsible for the anti-tumor effect of capsaicin are not yet completely understood. In this study, we investigated whether capsaicin induces apoptosis in colon cancer cell lines. Capsaicin decreased cell viability in a dose-dependent manner in Colo320DM and LoVo cells. In addition, capsaicin produced cell morphology changes and DNA fragmentation, decreased the DNA contents, and induced phosphatidylserine translocation, which is a hallmark of apoptotic cell death. We showed that capsaicin-induced apoptosis is associated with an increase in ROS generation and a disruption of the mitochondrial transmenbrane potential. A possible mechanism of capsaicin-induced apoptosis is the activation of caspase 3, a major apoptosis-executing enzyme. Treatment with capsaicin induced a dramatic increase in caspase 3 activity, as assessed by the cleavage of Ac-DEVD-AMC, a fluorogenic substrate. In conclusion, our results clearly showed that capsaicin induced apoptosis in colon cancer cells. Although the actual mechanisms of capsaicin-induced apoptosis remain uncertain, it may be a beneficial agent for colon cancer treatment and chemoprevention.</P>